fix(panel): flush the log before serving it

Splitting the log sink made its writes asynchronous, so a download could miss
the last lines still in the queue — silently, with a successful response. Those
are the lines the operator came for: a log is downloaded to find out what just
happened.

The panel is handed a barrier, not the sink: a func() set once at startup, the
same shape as the reconfigure hook and the stats setter already in the tree. It
cannot write, reconfigure or close, so it stays a consumer, and nothing about
the sink's type reaches it.

The wait is bounded at the sink's own control budget and enforced on the panel
side, so a wedged writer cannot turn the download into the new place the daemon
gets stuck — the very thing the async split was for. Past the bound the handler
serves what is on disk. With no barrier installed the path behaves as before.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

.gitea/workflows/release.yml

@@ -118,6 +118,79 @@ concurrency:
   cancel-in-progress: true
 
 jobs:
+  # ---------------------------------------------------------------------------
+  # THE TEST GATE (2026-07-26). Everything below `needs:` this job, so a red test
+  # stops the release instead of shipping with it.
+  #
+  # WHY IT IS A JOB HERE AND NOT JUST .gitea/workflows/test.yml: a separate
+  # workflow cannot block another one — they run side by side and a red `test`
+  # workflow would have published anyway. Only a `needs:` edge inside THIS
+  # workflow is a gate. test.yml exists too, for fast feedback on `main`; both
+  # call the same scripts/run-tests.sh so they cannot drift.
+  #
+  # WHAT WAS BROKEN: the release tract ran two `go test` invocations in total —
+  # build-shaterd.sh's one-package buildtags check and check-router-tags.sh's
+  # three named tests. 115 of the 116 test files under shater/** had never run in
+  # CI (upstream's .github/workflows/test.yml triggers on branches this fork does
+  # not have, and Gitea ignores .github/workflows entirely once .gitea/workflows
+  # exists). TestDNSFilterRemoteBlocklistHTTPClient shipped red twice.
+  #
+  # WHAT IT COVERS: the whole suite under the SHIPPED build tags
+  # (scripts/router-tags.sh) on linux — the two dimensions that were missing.
+  # transport/wireguard compiles 1 test file without the tag set and 7 with it
+  # (the AmneziaWG ones); shater/generate has 44 test files on linux against 32
+  # elsewhere. Plus a -race pass and the panel's TypeScript tests. Details and
+  # the named, reasoned exclusions are in scripts/run-tests.sh.
+  test:
+    name: test gate
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      # go.mod `replace`s wireguard-go to ./submodules/wireguard-go, so without
+      # this even `go list` fails. Same step/reason as in build-apk below.
+      - name: Init wireguard-go submodule (awg)
+        run: git submodule update --init --depth 1 submodules/wireguard-go
+
+      - name: Set up Go
+        uses: actions/setup-go@v5
+        with:
+          go-version-file: go.mod
+          cache: false              # explicit actions/cache@v3.3.2 below
+
+      # Same cache key as build-apk: this job runs first, so it warms the module
+      # + build cache the SDK-lane build then restores. (v3.3.2 pin: see header.)
+      - name: Cache Go modules + build cache
+        uses: actions/cache@v3.3.2
+        with:
+          path: |
+            ~/go/pkg/mod
+            ~/.cache/go-build
+          key: go-${{ hashFiles('go.sum') }}
+          restore-keys: |
+            go-
+
+      # Node 24, NOT the 20 build-apk uses for the SPA: panel's tests are
+      # TypeScript run directly by `node --test`, and type stripping only exists
+      # from 22.6 — on node 20 `npm test` dies before running a single case.
+      - name: Set up Node
+        uses: actions/setup-node@v4
+        with:
+          node-version: '24'
+
+      - name: Cache panel node_modules
+        uses: actions/cache@v3.3.2
+        with:
+          path: panel/node_modules
+          key: npm-${{ hashFiles('panel/package-lock.json') }}
+
+      - name: Panel tests
+        run: bash scripts/run-panel-tests.sh
+
+      - name: Go tests (shipped tags, linux, + race)
+        run: bash scripts/run-tests.sh
+
   # ---------------------------------------------------------------------------
   # Build the 4 packages through the ImmortalWrt 25.12 apk-SDK for the 25.12/apk
   # fleet (BPI-R3 mini on BananaWRT 25.12-mtk-vendor, BPI-R4 on OpenWrt 25.12,
@@ -125,6 +198,9 @@ jobs:
   # packages.adb + shater-apk.pem, uploaded as the artifact `apkfeed-<arch>`.
   build-apk:
     name: apk ${{ matrix.arch }}
+    # THE GATE EDGE. A red test skips this job, which leaves no artifact, which
+    # (with the guards in release-apk) leaves nothing published.
+    needs: test
     runs-on: ubuntu-latest
     strategy:
       fail-fast: false
@@ -302,11 +378,17 @@ jobs:
   # of that URL, so it is now written unconditionally and asserted afterwards.
   release-apk:
     name: release apk
-    needs: build-apk
+    needs: [test, build-apk]
     # Publish whatever arch feeds succeeded — do NOT block the aarch64 release
     # when an unrelated arch (e.g. x86_64) fails. download-artifact only fetches
     # artifacts that exist, and the publish loop skips missing apkfeed-* dirs.
-    if: ${{ !cancelled() }}
+    #
+    # `needs.test.result == 'success'` is the second half of the gate. Without
+    # it, `!cancelled()` is true when the test job FAILS (build-apk is then
+    # skipped), this job runs with no artifacts at all, and — see the guard at
+    # the end of the publish step — used to exit 0 having published nothing. Red
+    # tests must SKIP this job, not "succeed" through it.
+    if: ${{ !cancelled() && needs.test.result == 'success' }}
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
@@ -342,6 +424,14 @@ jobs:
           ROLLING: ${{ steps.rel.outputs.rolling }}
         run: |
           set -euo pipefail
+          # Counted, and asserted non-zero at the end. Until 2026-07-26 this loop
+          # was the step's whole body: with no artifacts the glob stayed
+          # unexpanded, `[ -d ... ]` was false, `continue` ran once, the loop
+          # ended and the step exited 0 — "release apk" went GREEN having
+          # published absolutely nothing. Any upstream failure (all arches
+          # failing to build, an artifact-name change, a download-artifact
+          # hiccup) therefore looked like a successful release.
+          published=0
           for d in artifacts/apkfeed-*; do
             [ -d "$d" ] || continue
             arch="${d#artifacts/apkfeed-}"
@@ -432,4 +522,15 @@ jobs:
               echo "        own rules, not by our intent."
               exit 14; }
             echo "[release-apk] OK — $ROLL serves $want"
+            published=$((published + 1))
           done
+
+          # The assert the loop above never had. Zero feeds published is a failed
+          # release, not a quiet success — say so with a non-zero exit.
+          if [ "$published" -eq 0 ]; then
+            echo "[release-apk] ERROR: no apkfeed-* artifact reached this job, so"
+            echo "        NOTHING was published. Downloaded tree:"
+            ls -la artifacts 2>&1 | sed 's/^/          /' || echo "          (no artifacts/ dir at all)"
+            exit 10
+          fi
+          echo "[release-apk] published $published arch feed(s)"

.gitea/workflows/test.yml

@@ -0,0 +1,85 @@
+# Shater — the test gate, on every push to `main`.
+#
+# WHY THIS FILE EXISTS (2026-07-26)
+#   The fork had a full suite and no CI that ran it. Upstream's
+#   .github/workflows/test.yml triggers on `stable`/`testing`/`unstable`; this
+#   repo only has `main`. And Gitea does not read .github/workflows AT ALL once
+#   .gitea/workflows exists — so those files are decoration here. Result: 115 of
+#   the 116 test files under shater/** had never once executed in CI, and
+#   TestDNSFilterRemoteBlocklistHTTPClient stayed red across two published
+#   releases.
+#
+# RELATIONSHIP TO release.yml
+#   This workflow is the FAST FEEDBACK loop on `main`. It is NOT the release
+#   gate: a separate workflow cannot block another one. The gate is the `test`
+#   JOB inside .gitea/workflows/release.yml, which build-apk `needs:` — see the
+#   comment there. Both run the very same scripts/run-tests.sh, so they cannot
+#   drift apart.
+name: test
+
+on:
+  push:
+    branches: [main]
+    paths-ignore:
+      - '**.md'
+      - 'docs-shater/**'
+  pull_request:
+    branches: [main]
+  workflow_dispatch:
+
+concurrency:
+  group: test-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  test:
+    name: go + panel tests
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      # go.mod has `replace github.com/sagernet/wireguard-go => ./submodules/
+      # wireguard-go`, so WITHOUT this every `go list`/`go test` fails before it
+      # starts. Same step, same reason, as in release.yml's build job.
+      - name: Init wireguard-go submodule (awg)
+        run: git submodule update --init --depth 1 submodules/wireguard-go
+
+      - name: Set up Go
+        uses: actions/setup-go@v5
+        with:
+          go-version-file: go.mod
+          cache: false              # explicit actions/cache@v3.3.2 below
+
+      # v3.3.2 is the last release speaking the cache API act_runner implements
+      # (see the header of release.yml). Same key as the release build job, so
+      # whichever runs first warms the other.
+      - name: Cache Go modules + build cache
+        uses: actions/cache@v3.3.2
+        with:
+          path: |
+            ~/go/pkg/mod
+            ~/.cache/go-build
+          key: go-${{ hashFiles('go.sum') }}
+          restore-keys: |
+            go-
+
+      # Node 24, NOT the 20 the SPA build uses: panel's tests are TypeScript run
+      # through `node --test`, and type stripping only exists from 22.6. On
+      # node 20 `npm test` dies with a syntax error before running anything.
+      - name: Set up Node
+        uses: actions/setup-node@v4
+        with:
+          node-version: '24'
+
+      - name: Cache panel node_modules
+        uses: actions/cache@v3.3.2
+        with:
+          path: panel/node_modules
+          key: npm-${{ hashFiles('panel/package-lock.json') }}
+
+      - name: Panel tests
+        run: bash scripts/run-panel-tests.sh
+
+      - name: Go tests (shipped tags, linux, + race)
+        run: bash scripts/run-tests.sh

.gitmodules

@@ -7,4 +7,10 @@
 [submodule "submodules/wireguard-go"]
 	path = submodules/wireguard-go
 	url = https://github.com/Leadaxe/wireguard-go-awg2-lx
-	branch = lx
+	# The pin lives on lx-awg2-v005, NOT on lx: the two are separate lines (42
+	# commits apart one way, 131 the other). `lx` has no hasReserved() gate in
+	# conn/bind_std.go at all, so a `git submodule update --remote` against it
+	# would silently restore the bug where ClientBind/StdNetBind shred the
+	# AmneziaWG magic header and no chain carries traffic. Keep this pointing at
+	# the line the pin is actually on.
+	branch = lx-awg2-v005

README.en.md

@@ -32,7 +32,9 @@ single-use token into the standalone SPA the daemon serves on its own port
 
 ## Highlights
 
-- Transparent **TPROXY** data plane (TCP + UDP), SNI/Host/QUIC sniffing, no DNS leaks.
+- Transparent **TPROXY** data plane (TCP + UDP), SNI/Host/QUIC sniffing, no DNS leaks
+  — `:53` interception is on by default and covers the queries a client sends to the
+  router itself, not just the ones aimed around it (`globals.dns_intercept`, D24).
 - First-match routing by source / destination / list / geo / client → outbound /
   selector / chain / direct / block; node groups with balancer/observatory;
   multi-hop chains; per-rule egress.

SPECS/007-AWG_OVER_WIREGUARD_DETOUR_GUARD/SPEC.md

@@ -3,7 +3,33 @@
 | Поле | Значение |
 |------|----------|
 | Тип | B (bug) |
-| Статус | C (complete) |
+| Статус | C (complete) — guard **снят** (см. баннер ниже) |
+
+> ## ⛔️ Guard снят (2026-07-26) — первопричина к shater не относится
+> **Оба guard'а (Start-guard в `protocol/wireguard/endpoint.go` и
+> selector-guard в `protocol/group/awg_selector_guard.go`) удалены**, вместе с
+> их adapter-хуками (`OutboundManager.ConsumersOf`, `AmneziaWGSuspendable`).
+> Апстрим снял их коммитом `5fa3a0a17`; сюда снятие приехало отдельно.
+>
+> **Почему.** Зависание было **Android-специфичным** (`Libbox.newService` не
+> возвращал управление). Android для shater не платформа и ей не станет —
+> мы собираем роутерный бинарь под OpenWrt/aarch64. При этом лекарство для
+> самой AWG-за-detour связки у нас уже есть: reserved-clear gate в
+> `ClientBind` (`d971eb85e` + пин сабмодуля `7d15f33`), без которого AWG не
+> поднимался вообще ни за каким detour'ом. Мы носили и лекарство, и запрет
+> на его применение.
+>
+> **Чем это было плохо на практике.** Guard отказывал **молча**: не ошибкой,
+> а `started=false`, после чего каждый дозвон падал с «WireGuard is not ready
+> yet». Конфигурация «AmneziaWG за WireGuard-хопом» выглядела не как
+> отклонённая, а как «нода почему-то не работает».
+>
+> **Регрессия:** `protocol/wireguard/awg_over_wireguard_start_lx_test.go`
+> (`with_gvisor && with_awg`) — AWG-эндпоинт с `detour` на outbound типа
+> `wireguard` доходит до PostStart и поднимает `started`. До снятия guard'а
+> тест краснел.
+>
+> **Осталось:** сквозной прогон на железе (AWG поверх реального WG-хопа).
 
 Отклонять (по образцу ядрового запрета «empty direct detour») конфигурацию, где
 AmneziaWG-endpoint (источник с AWG-полями) имеет `detour` на **любой

adapter/outbound.go

@@ -45,30 +45,8 @@ type OutboundManager interface {
 	Default() Outbound
 	Remove(tag string) error
 	Create(ctx context.Context, router Router, logger log.ContextLogger, tag string, outboundType string, options any) error
-	// lx:begin awg
-	// ConsumersOf returns the tags of outbounds that depend on (detour through)
-	// the given tag — the reverse of Dependencies(). Used by the selector guard to
-	// walk up to AmneziaWG consumers when a group switches to a WireGuard member.
-	ConsumersOf(tag string) []string
-	// lx:end awg
 }
 
-// lx:begin awg
-// AmneziaWGSuspendable is implemented by an AmneziaWG endpoint so the selector
-// guard can suspend it (bring its device down) when a group it detours through
-// switches to a WireGuard member — AmneziaWG inside a WireGuard tunnel hangs the
-// kernel on Android. The marker lives in adapter so protocol/group can act on it
-// without importing protocol/wireguard.
-type AmneziaWGSuspendable interface {
-	// IsAmneziaWG reports whether this endpoint runs AmneziaWG (has AWG params).
-	IsAmneziaWG() bool
-	// SuspendAmneziaWG brings the device down so no junk handshake is sent. It is
-	// idempotent and safe to call on a not-yet-started or already-suspended endpoint.
-	SuspendAmneziaWG()
-}
-
-// lx:end awg
-
 // lx:begin idle-suspend
 // IdleSuspendable is implemented by a WG/AWG endpoint so the router's idle tick
 // (SPEC 020) can suspend it when it is idle and unreachable, without importing

adapter/outbound/manager.go

@@ -208,21 +208,6 @@ func (m *Manager) Outbound(tag string) (adapter.Outbound, bool) {
 	return m.endpoint.Get(tag)
 }
 
-// lx:begin awg
-// ConsumersOf returns a copy of the tags that detour through tag (reverse of
-// Dependencies()), built from the dependByTag ledger populated at Create time.
-func (m *Manager) ConsumersOf(tag string) []string {
-	m.access.RLock()
-	defer m.access.RUnlock()
-	consumers := m.dependByTag[tag]
-	if len(consumers) == 0 {
-		return nil
-	}
-	return append([]string(nil), consumers...)
-}
-
-// lx:end awg
-
 func (m *Manager) Default() adapter.Outbound {
 	m.access.RLock()
 	defer m.access.RUnlock()

common/dialer/udp_fragment_df_darwin_lx_test.go

@@ -0,0 +1,35 @@
+//go:build darwin
+
+package dialer
+
+import (
+	"syscall"
+	"testing"
+
+	"golang.org/x/sys/unix"
+)
+
+// udpSocketDFSet reports whether the socket has "don't fragment" forced on
+// (control.DisableUDPFragment sets IP_DONTFRAG=1 on darwin).
+func udpSocketDFSet(t *testing.T, sysConn syscall.Conn) bool {
+	t.Helper()
+	rawConn, err := sysConn.SyscallConn()
+	if err != nil {
+		t.Fatal(err)
+	}
+	var (
+		value   int
+		sockErr error
+		ctrlErr error
+	)
+	ctrlErr = rawConn.Control(func(fd uintptr) {
+		value, sockErr = unix.GetsockoptInt(int(fd), unix.IPPROTO_IP, unix.IP_DONTFRAG)
+	})
+	if ctrlErr != nil {
+		t.Fatal(ctrlErr)
+	}
+	if sockErr != nil {
+		t.Fatal(sockErr)
+	}
+	return value != 0
+}

common/dialer/udp_fragment_df_linux_lx_test.go

@@ -0,0 +1,36 @@
+//go:build linux
+
+package dialer
+
+import (
+	"syscall"
+	"testing"
+
+	"golang.org/x/sys/unix"
+)
+
+// udpSocketDFSet reports whether the socket has "don't fragment" forced on
+// (control.DisableUDPFragment sets IP_MTU_DISCOVER=IP_PMTUDISC_DO on linux,
+// the same flag the user-visible failure was traced to on android).
+func udpSocketDFSet(t *testing.T, sysConn syscall.Conn) bool {
+	t.Helper()
+	rawConn, err := sysConn.SyscallConn()
+	if err != nil {
+		t.Fatal(err)
+	}
+	var (
+		value   int
+		sockErr error
+		ctrlErr error
+	)
+	ctrlErr = rawConn.Control(func(fd uintptr) {
+		value, sockErr = unix.GetsockoptInt(int(fd), unix.IPPROTO_IP, unix.IP_MTU_DISCOVER)
+	})
+	if ctrlErr != nil {
+		t.Fatal(ctrlErr)
+	}
+	if sockErr != nil {
+		t.Fatal(sockErr)
+	}
+	return value == unix.IP_PMTUDISC_DO
+}

common/dialer/udp_fragment_df_other_lx_test.go

@@ -0,0 +1,14 @@
+//go:build !darwin && !linux && !windows
+
+package dialer
+
+import (
+	"syscall"
+	"testing"
+)
+
+func udpSocketDFSet(t *testing.T, _ syscall.Conn) bool {
+	t.Helper()
+	t.Skip("DF socket-flag introspection implemented for darwin, linux and windows only")
+	return false
+}

common/dialer/udp_fragment_df_windows_lx_test.go

@@ -0,0 +1,43 @@
+//go:build windows
+
+package dialer
+
+import (
+	"syscall"
+	"testing"
+
+	"golang.org/x/sys/windows"
+)
+
+// IP_MTU_DISCOVER on windows (ws2ipdef.h); control.DisableUDPFragment sets it to
+// IP_PMTUDISC_DO, the same "don't fragment" state the linux helper checks.
+const (
+	windowsIPMTUDiscover = 71
+	windowsPMTUDiscDo    = 1
+)
+
+// udpSocketDFSet reports whether the socket has "don't fragment" forced on.
+// shater addition: upstream ships linux + darwin only, so the whole suite
+// skipped on the dev host — where it is the one platform we can actually run it
+// on before the router build.
+func udpSocketDFSet(t *testing.T, sysConn syscall.Conn) bool {
+	t.Helper()
+	rawConn, err := sysConn.SyscallConn()
+	if err != nil {
+		t.Fatal(err)
+	}
+	var (
+		value   int
+		sockErr error
+	)
+	ctrlErr := rawConn.Control(func(fd uintptr) {
+		value, sockErr = windows.GetsockoptInt(windows.Handle(fd), windows.IPPROTO_IP, windowsIPMTUDiscover)
+	})
+	if ctrlErr != nil {
+		t.Fatal(ctrlErr)
+	}
+	if sockErr != nil {
+		t.Skip("IP_MTU_DISCOVER is not readable on this host: ", sockErr)
+	}
+	return value == windowsPMTUDiscDo
+}

common/dialer/udp_fragment_lx_test.go

@@ -0,0 +1,99 @@
+// lx: regression tests for the udp_fragment / UDPFragmentDefault
+// plumbing. The WireGuard endpoint (and MASQUE outbound) rely on
+// UDPFragmentDefault=true reaching the real UDP socket as "DF clear": with DF
+// set, an outer datagram larger than the path MTU is silently dropped instead
+// of fragmented, which blackholes nested tunnels (AWG-over-AWG, MASQUE-over-AWG)
+// and AWG s4 transport junk. These tests assert the socket flag itself, on both
+// paths a WireGuard bind can take: the dialer (ClientBind, detour case) and the
+// listener control (StdNetBind via WireGuardControl, no-detour case).
+package dialer
+
+import (
+	"context"
+	"net"
+	"syscall"
+	"testing"
+
+	"github.com/sagernet/sing-box/option"
+	M "github.com/sagernet/sing/common/metadata"
+	N "github.com/sagernet/sing/common/network"
+)
+
+func dialUDPForDF(t *testing.T, options option.DialerOptions) syscall.Conn {
+	t.Helper()
+	d, err := NewDefault(context.Background(), options)
+	if err != nil {
+		t.Fatal(err)
+	}
+	conn, err := d.DialContext(context.Background(), N.NetworkUDP, M.ParseSocksaddr("127.0.0.1:9"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { _ = conn.Close() })
+	sysConn, isSysConn := conn.(syscall.Conn)
+	if !isSysConn {
+		t.Fatalf("dialed UDP conn %T does not expose SyscallConn", conn)
+	}
+	return sysConn
+}
+
+func listenUDPForDF(t *testing.T, options option.DialerOptions) syscall.Conn {
+	t.Helper()
+	d, err := NewDefault(context.Background(), options)
+	if err != nil {
+		t.Fatal(err)
+	}
+	// WireGuardControl() is the listener control conn.StdNetBind installs on the
+	// socket a no-detour WireGuard endpoint sends its outer datagrams from — the
+	// exact socket the DF default decides the fate of.
+	listenConfig := net.ListenConfig{Control: d.WireGuardControl()}
+	packetConn, err := listenConfig.ListenPacket(context.Background(), "udp4", "127.0.0.1:0")
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { _ = packetConn.Close() })
+	sysConn, isSysConn := packetConn.(syscall.Conn)
+	if !isSysConn {
+		t.Fatalf("listened UDP conn %T does not expose SyscallConn", packetConn)
+	}
+	return sysConn
+}
+
+// Upstream default: no UDPFragmentDefault, no udp_fragment → DF is set on both
+// the dial and listener paths. Pins the baseline the endpoint fix opts out of.
+func TestUDPFragmentDFByDefault_LX(t *testing.T) {
+	if !udpSocketDFSet(t, dialUDPForDF(t, option.DialerOptions{})) {
+		t.Fatal("default dialer must set DF on dialed UDP sockets")
+	}
+	if !udpSocketDFSet(t, listenUDPForDF(t, option.DialerOptions{})) {
+		t.Fatal("default dialer must set DF on listener-control UDP sockets")
+	}
+}
+
+// UDPFragmentDefault=true (what the WireGuard endpoint and MASQUE outbound now
+// set) → DF clear on both paths, so oversize outer datagrams fragment instead
+// of vanishing.
+func TestUDPFragmentDefaultClearsDF_LX(t *testing.T) {
+	options := option.DialerOptions{UDPFragmentDefault: true}
+	if udpSocketDFSet(t, dialUDPForDF(t, options)) {
+		t.Fatal("UDPFragmentDefault=true must leave DF clear on dialed UDP sockets")
+	}
+	if udpSocketDFSet(t, listenUDPForDF(t, options)) {
+		t.Fatal("UDPFragmentDefault=true must leave DF clear on listener-control UDP sockets")
+	}
+}
+
+// Explicit user config always wins over the protocol default, in both
+// directions.
+func TestUDPFragmentExplicitOverride_LX(t *testing.T) {
+	fragmentOff := false
+	options := option.DialerOptions{UDPFragment: &fragmentOff, UDPFragmentDefault: true}
+	if !udpSocketDFSet(t, dialUDPForDF(t, options)) {
+		t.Fatal("udp_fragment=false must set DF even when the protocol default allows fragmentation")
+	}
+	fragmentOn := true
+	options = option.DialerOptions{UDPFragment: &fragmentOn}
+	if udpSocketDFSet(t, dialUDPForDF(t, options)) {
+		t.Fatal("udp_fragment=true must leave DF clear even without a protocol default")
+	}
+}

common/tlsspoof/integration_test.go

@@ -25,6 +25,21 @@ func requireRoot(t *testing.T) {
 	}
 }
 
+// requireTCPDump skips when tcpdump is not installed.
+//
+// The same honesty this package's callers demand of a health reading: a missing
+// INSTRUMENT is "not checked", never "broken". Without it every test in this
+// file fails on `cmd.Start()` — sixteen red results that say nothing about the
+// code and hide any real failure among them — on a machine where the only thing
+// wrong is that a capture tool is absent. requireRoot has always drawn that line
+// for privileges; this draws it for the tool.
+func requireTCPDump(t *testing.T) {
+	t.Helper()
+	if _, err := exec.LookPath("tcpdump"); err != nil {
+		t.Skip("integration test requires tcpdump on PATH; install it to run this suite")
+	}
+}
+
 func tcpdumpObserver(t *testing.T, iface string, port uint16, needle string, do func(), wait time.Duration) bool {
 	t.Helper()
 	return tcpdumpObserverMulti(t, iface, port, []string{needle}, do, wait)[needle]
@@ -36,6 +51,9 @@ func tcpdumpObserver(t *testing.T, iface string, port uint16, needle string, do
 // the wire.
 func tcpdumpObserverMulti(t *testing.T, iface string, port uint16, needles []string, do func(), wait time.Duration) map[string]bool {
 	t.Helper()
+	// Every capture in this file funnels through here, so one guard covers the
+	// whole suite and no future test can forget it.
+	requireTCPDump(t)
 	ctx, cancel := context.WithTimeout(context.Background(), wait)
 	defer cancel()
 	cmd := exec.CommandContext(ctx, "tcpdump", "-i", iface, "-n", "-A", "-l",

common/urltest/probegate_lx.go

@@ -0,0 +1,61 @@
+package urltest
+
+// lx: health board §5.C — the reachability half of "should this be probed".
+//
+// # Two different reasons not to probe, and why they cannot be one flag
+//
+// A group's OWN probing schedule is stood down for two unrelated reasons, and
+// conflating them breaks one of the two:
+//
+//   - NOT USED — no enabled routing rule reaches this group, so probing it
+//     measures a path nothing travels. That is a property of the CONFIG, it is
+//     decided once when the config is generated, and it travels in the config
+//     itself (option.URLTestOutboundOptions.SelfCheck). It cannot change while
+//     the box runs, because the rules cannot change while the box runs.
+//
+//   - NOT REACHABLE RIGHT NOW — the group is a hop of a chain and a hop in
+//     FRONT of it is currently dead. Every member of this group dials through
+//     that hop, so every probe would fail inside it: the measurement would be
+//     about the broken hop, and would be recorded against this one. That is a
+//     property of the WORLD, it changes minute by minute, and it must be
+//     re-asked every time rather than baked into the config — a hop that comes
+//     back must resume probing on its own, with no reapply and nobody pressing
+//     anything.
+//
+// ProbeGate is the second one. It is deliberately a QUESTION asked at the
+// moment of probing and never a stored answer: there is no flag to set, so
+// there is no flag to forget to clear.
+//
+// The gate governs the group's own SCHEDULE only — the warm-up sweep and the
+// ticker. An explicit check (a human, an API call) is a deliberate request and
+// is never refused, exactly as with SelfCheck.
+type ProbeGate interface {
+	// ProbeAllowed reports whether the outbound tagged tag may run its own
+	// scheduled probe right now.
+	//
+	// Implementations MUST answer true when they do not know: a gate that
+	// refuses on missing information would silence probing precisely when the
+	// system has the least idea what is going on, and nothing would ever
+	// measure its way out of that. A nil ProbeGate means "no gate" and every
+	// probe proceeds.
+	ProbeAllowed(tag string) bool
+
+	// ProbeWhenIdle reports whether the outbound tagged tag must keep measuring
+	// even when no traffic is passing through it.
+	//
+	// A urltest group normally probes only while it is in use: Touch arms the
+	// ticker on a dial, and the idle timeout stops it again. That is right for a
+	// group whose readings matter only while somebody is dialling it, and wrong
+	// for one the routing config REACHES: a rule that matches rarely — a narrow
+	// domain list, say — is in force the whole time, so the health of its target
+	// is a live question the whole time. Letting it go quiet means the panel
+	// reports "untested" about a rule that is armed, and the first real request
+	// pays a cold probe instead of picking an already-known-good member.
+	//
+	// Unlike ProbeAllowed, the safe answer here is FALSE when nothing is known.
+	// This one ADDS work, and a gate that claimed it on missing information would
+	// keep every group in the process probing forever — not a default anybody
+	// asked for. Absent gate, unknown tag, nothing configured yet: false, and the
+	// idle timeout behaves exactly as it always has.
+	ProbeWhenIdle(tag string) bool
+}

docs-shater/DECISIONS.md

@@ -666,3 +666,109 @@ Neither is a substitute for the other. A new protocol in `shater/parse` +
   stays only so the router set remains a subset of the lx desktop set. Noted
   because "a tag that buys nothing" is the mirror image of this bug and should be
   removed deliberately, not silently.
+
+## D24 — DNS interception is the DEFAULT (`dns_intercept=1`), not an opt-in
+Decided 2026-07-26. `Globals.DNSIntercept` shipped as opt-in (`default false`, and
+absent from both `DefaultGlobals` and the shipped `/etc/config/shater`). The result
+was an **inverted** posture, which is the reason this is a decision and not a
+preference:
+
+- a client with **standard** settings — DNS = the router's address, exactly what
+  DHCP hands out — sent its queries to the router. The nft `:53` divert was behind
+  the flag (`netplane/nft.go`), and the rule right after it is an unconditional
+  `fib daddr type local accept`, so the query was delivered locally to dnsmasq and
+  forwarded to the ISP **in the clear**: no blocklists, no per-device DNS rules,
+  no Block-DoH, no resolver detour, nothing;
+- a client that hard-coded `8.8.8.8` "to bypass the router" was addressing a
+  non-local IP and **was** caught by the ordinary tproxy catch-all.
+
+The obedient client leaked; the evader did not. Meanwhile `FEATURES.md`, `README.md`
+and D14 all promised "no DNS leaks" and "dnsmasq never sees LAN queries" — true only
+for the traffic pattern the default did not cover. `dns_intercept` appeared nowhere
+in `docs-shater/` at all.
+
+**Decision: `DNSIntercept` is seeded ON in `model.DefaultGlobals`, and the shipped
+`/etc/config/shater` carries an explicit `option dns_intercept '1'`.** Nothing about
+the interception MECHANISM changed — only which side of the switch is the default.
+
+**`.lan` and the private PTR zones keep working, and that is a pre-existing part of
+the mechanism, not something bolted on for this flip.** `generate/dns.go` adds a
+synthetic DNS server (`shater-local-dns`, plain UDP to `127.0.0.1:53`, detour
+`direct`, so the daemon's own loop-mark keeps it out of the divert) and PREPENDS a
+`domain_suffix` rule for `lan` + the RFC6303 private reverse zones, ahead of every
+device/filter rule. Two honest limitations: it hardcodes `lan` (a router whose
+dnsmasq domain was changed needs a `config dns_rule` for the new suffix), and it
+only exists when the model has at least one `config resolver` — with none, buildDNS
+emits no DNS plane at all and the engine falls back to its built-in `local`
+transport, which reads `/etc/resolv.conf` (127.0.0.1 → dnsmasq), so local names
+still resolve but nothing is filtered.
+
+**A dead engine does NOT black out the LAN's DNS.** This was the first thing checked,
+because "intercept everything" invites the reading "engine down = no DNS anywhere",
+and that is not what happens:
+- the fail-closed **holding plane** (D17, `RenderHoldNft`) hooks `forward` ONLY.
+  A query addressed to the router is INPUT-hook traffic, so dnsmasq answers it as
+  it always did — unfiltered and plaintext to the ISP. Deliberate: blocking it
+  would also cut the daemon's own name resolution and with it any chance of
+  self-recovery;
+- with the FULL plane loaded and the engine's tproxy socket gone, the `tproxy`
+  statement returns `NFT_BREAK`, which aborts its own rule; the packet continues
+  down the chain into the same `fib daddr type local accept` and reaches dnsmasq.
+
+So the failure mode is a DNS **fail-open** (working, unfiltered) while client
+TRAFFIC stays fail-closed — and a query aimed at an EXTERNAL resolver is dropped
+with the rest of the forwarded traffic. Operators must know this: "the tunnel is
+down" does not mean "DNS is private".
+
+**Existing installs.** `/etc/config/shater` is a conffile
+(`openwrt/shater-core/Makefile`), so an upgrade never replaces it:
+- a config that never mentioned the option (all of them, before this change) now
+  parses over the ON seed and **starts intercepting on the next apply**. That is the
+  intended behaviour change, and the only one this decision makes;
+- an explicit `option dns_intercept '0'` keeps winning. It survives the
+  `WriteUCI→ReadUCI` round-trip because `render.go` emits booleans ALWAYS —
+  the trap a default-true bool has and a default-false one does not: a value
+  omitted at false would come back as the seed and silently re-enable itself.
+  `shater/model/dnsintercept_test.go` pins both directions, plus the shipped file.
+
+**Not done: silencing the "no resolvers configured" warning by shipping a resolver.**
+With interception on and no `config resolver`, generate warns — and it is right to:
+every client query now lands in an engine that has no resolver plane, so it is
+answered by the system resolver (dnsmasq → the ISP, in the clear) with filtering and
+anti-leak inert. Shipping a `type local` resolver would make the warning disappear
+while changing nothing about where the queries go: the panel would show a configured
+resolver and the operator would believe DNS was handled. That is the inverted lie
+this project keeps deleting. The warning stays; what it needs is the accurate
+wording (it currently claims `.lan` breaks, which the fallback above disproves), not
+a workaround. Note also that a fresh install ships INERT (`enabled '0'`) and
+`Reconcile` tears down instead of generating, so the warning cannot appear before the
+operator has enabled the stack — at which point it describes their live config.
+
+**OPEN, and it gates shipping this default: the synthetic local server changes how
+proxy-endpoint DOMAINS are resolved.** Found while landing D24, reproduced on Linux
+with one resolver and a node addressed by a hostname:
+
+- `common/dialer/dialer.go` resolves a domain server address through
+  `route.default_domain_resolver`; when that is unset it uses
+  `dnsTransport.Default()` — the engine's built-in `local` transport, i.e. a
+  bootstrap-DIRECT lookup — but **only while fewer than two DNS transports exist**.
+  With two or more and no default, it reports the `missing-domain-resolver`
+  deprecation and leaves the query transport nil, so `dns.Router.Lookup` falls back
+  to `lookupWithRules`: the CLIENT DNS plane.
+- `dns_intercept` adds `shater-local-dns`, which takes a single-resolver config from
+  one transport to two. So a config whose only resolver is DoH-through-the-tunnel —
+  the recommended anti-leak setup — would start resolving its own node's hostname
+  through that same tunnel: a bootstrap loop where there was none.
+- Evidence: the same model emits no deprecation notice with `dns_intercept=0` and
+  two `missing-domain-resolver` notices with `dns_intercept=1`;
+  `generate.TestDNSFilterRemoteBlocklistHTTPClient` (Linux-only) fails on exactly
+  that notice and is deliberately left failing rather than relaxed.
+
+The fix belongs in `generate` (`route.go:160` already sets
+`route.default_domain_resolver` from `endpointResolver()`, which is opt-in and unset
+by default): when buildDNS emits the synthetic local server and no endpoint resolver
+is configured, `default_domain_resolver` must be pointed at a bootstrap-direct
+server, which restores exactly the pre-D24 behaviour and clears the notice. Until
+that lands, an operator can get the same result by setting `endpoint_resolver` to a
+direct resolver. Note the hazard is **not** created by D24 — any config with two
+resolvers has it today; the default merely makes it universal.

docs-shater/FEATURES.md

@@ -40,6 +40,16 @@ usable release, **[T1]** next, **[T2]** later. Phases refer to `ROADMAP.md`.
   type=fakeip + pool — there is no global "FakeIP mode"); no DNS leaks. Routing
   is decided by in-engine rule-sets — the v0.1 dnsmasq→nftset population
   mechanism does not exist in v0.2 (see generate/dns.go).
+  The hijack covers the queries a client sends **to the router itself** — the
+  address DHCP hands out — because `globals.dns_intercept` is **ON by default**
+  (D24). With it off, those queries go to dnsmasq and out to the ISP in the clear,
+  so the well-behaved client leaks while the one that hard-codes 8.8.8.8 does not.
+  `.lan` and the private PTR zones are preserved through dnsmasq either way. Two
+  things the promise does NOT cover, both by design: while the engine is DOWN the
+  holding plane hooks `forward` only, so dnsmasq still answers router-addressed
+  :53 unfiltered (client traffic and DNS to external resolvers stay blocked); and
+  with no `config resolver` at all there is no DNS plane to filter with — queries
+  fall through to the system resolver and generate says so.
 - **[MVP]** Client DoT/DoH blocking (stop devices bypassing the filter).
 - **[MVP]** **Blocklists** with **flexible sources**: `inline` (type your own) /
   `file` / `url` (auto-update) / `geosite` category (only when geodata present).

docs-shater/INSTALL.md

@@ -186,6 +186,38 @@ daemon (`shaterd run`), which owns the engine, the `inet shater` data plane, pol
 routing, in-process DNS, and the admin panel (default `:8088`). The LuCI app's
 "Open panel" button mints a single-use token and hands the browser off to the panel.
 
+### What enabling does to DNS
+
+From the first apply, **every** LAN plaintext `:53` goes into the engine — including
+the queries a client sends to the router's own address, which is what DHCP hands out.
+That is `globals.dns_intercept`, and it is **on by default** (D24); without it those
+queries reach dnsmasq and the ISP unfiltered, i.e. the client with default settings
+leaks while the one that hard-coded `8.8.8.8` does not. What follows from it:
+
+- `.lan` and private reverse (PTR) lookups still go to dnsmasq — the engine gets a
+  rule for those suffixes. If you renamed dnsmasq's domain away from `lan`, add a
+  `config dns_rule` for the new suffix.
+- Configure at least one `config resolver`. With none, the engine has no resolver
+  plane: intercepted queries fall through to the system resolver (dnsmasq → your
+  ISP, in the clear), blocklists and per-device DNS rules are inert, and the apply
+  says so in its warnings.
+- While the engine is DOWN, DNS is **not** blacked out: the fail-closed holding
+  plane hooks `forward` only, so dnsmasq keeps answering router-addressed `:53`
+  (unfiltered, plaintext) while client traffic and DNS to external resolvers stay
+  blocked. "The tunnel is down" is not "DNS is private".
+
+To opt out, on the router:
+
+```sh
+uci set shater.globals.dns_intercept=0
+uci commit shater
+shaterd apply
+```
+
+Your `0` is kept: `/etc/config/shater` is a conffile (upgrades never replace it) and
+the daemon always writes the option back explicitly, so it is never re-enabled by a
+default.
+
 ## 5. The signed apk repo (the normal install path)
 
 OpenWrt/ImmortalWrt **25.12** packages with Alpine's **apk**: `.apk` files, a

docs-shater/PORTING.md

@@ -251,7 +251,40 @@ Apply/rollback: `apSnapshot` (run→last-good, nft→last-good.nft, route marks)
 > v0.2: "restart engine only on change" → config-hash gate + Close+New box (no reload).
 
 ### uci.go — `/etc/config/shater` schema
-- `config globals`: enabled, loglevel, kill_switch, dns_mode, ipv6, fwmark_base, table_base, confirm_timeout, resolver_default, resolver_fallback, probe_url, probe_interval, schema_version, active_profile.
+- `config globals` — the full option set, with the value used when the option is
+  ABSENT (the `model.DefaultGlobals` seed). Booleans are always written back as
+  `'1'`/`'0'` by `render.go`, so an explicit value never decays into the seed:
+
+  | option | default | meaning |
+  |---|---|---|
+  | `enabled` | `0` as shipped | master switch; `0` ⇒ `Reconcile` tears the stack down instead of applying |
+  | `loglevel` (alias `log_level`) | `warning` | engine + daemon level; `none/off/silent/disabled` ⇒ log disabled, unknown ⇒ `warn` + a validation warning |
+  | `log_syslog` / `log_file` / `log_persist` | `1` / `1` / `0` | operational log (`shater/logsink`): syslog, rotated file, and whether that file lives on flash instead of tmpfs |
+  | `log_max_kb` | `2048` | size cap of the log file, clamped to 128…8192; `0` = "use the default", not "off" |
+  | `kill_switch` | `closed` | `closed` = fail-closed (block on engine loss, incl. a holding plane when the engine never started); `open` = plain routing |
+  | `ipv6` | `1` | `0` drops LAN IPv6 in the forward chain instead of leaving it unproxied |
+  | `fwmark_base` / `table_base` | `0x2000` | reserved fwmark / routing-table bases (must not collide with fw4 or other apps) |
+  | `confirm_timeout` | `0` | seconds before an unconfirmed apply auto-rolls back; `0` = commit-confirm off |
+  | `resolver_default` / `resolver_fallback` / `endpoint_resolver` | unset | `config resolver` names: the DNS catch-all, its failover chain, and the bootstrap-direct server that resolves proxy endpoint DOMAINS |
+  | `probe_url` / `probe_interval` | engine defaults | the ONE instrument all health probing uses (D20 — there are no per-group overrides) |
+  | `panel_port` | `0` ⇒ `8088` | admin-panel HTTP port |
+  | `dns_filter` | `0` | master enable of the blocklist/allowlist filter (D15); needs at least one `config resolver` |
+  | `dns_intercept` | **`1`** | force ALL LAN plaintext `:53` into the engine, INCLUDING queries addressed to the router itself. See D24 for why this is the default, what preserves `.lan`, and what happens while the engine is down |
+  | `block_doh` | `0` | NXDOMAIN the known public DoH hostnames + the Firefox canary and reject `:443` to their IPs, so clients fall back to `:53` (which the engine catches) |
+  | `group_health` | `1` | OUR background group probing (the observatory). Does not touch sing-box's own urltest inside a group |
+  | `untunnelable` | `block` | policy for what TPROXY cannot carry (ICMP/IGMP/ESP/AH/GRE/SCTP): `block` \| `icmp` (echo out, rest dropped) \| `direct` (all out, bypassing the tunnel) |
+  | `geo_provider` | unset = auto | `sagernet` \| `loyalsoldier` \| `metacubex` \| `custom`; auto = country codes from SagerNet, everything else from Loyalsoldier |
+  | `geosite_url` / `geoip_url` | unset | `{category}` templates, honoured only when `geo_provider=custom` |
+  | `geosite_index_url` / `geoip_index_url` | unset | git-trees URLs used to SUGGEST categories in the panel; empty = no suggestions |
+  | `stats_backend` | `memory` | `off` (no aggregation at all) \| `memory` (RAM, lost on restart) \| `sqlite` (aggregates in RAM + query/connection log on disk) |
+  | `stats_ring_size` / `stats_timeline_minutes` / `stats_max_domains` | `200` / `60` / `5000` | live-log length, sparkline minutes, domain-map cap. **`0` = UNLIMITED** (grows with traffic), which is why these three are always emitted |
+  | `stats_disk_limit_mb` | `64` | on-disk cap of `stats.db`; only meaningful for `stats_backend=sqlite`; `0` = unlimited |
+  | `stats_retention_disabled` | `0` | master switch that turns OFF all trimming/pruning — every aggregate then grows unbounded |
+  | `schema_version` | `0` = pre-versioned | UCI schema revision; `shaterd migrate` writes `2` |
+  | `active_profile` | unset | display bookkeeping: the last profile switched to |
+
+  Deleted options still parse (unknown keys are ignored) and drain out on the next
+  render: `dns_mode` (D17 — fake-IP is a resolver TYPE), `sweep_interval` (D19).
 - `config inbound`: name, enabled, type, network, tproxy_port(12345), listen, port, auth, user, pass, target_addr, target_port, target_network, tcp, udp, sniff.
 - `config subscription`: name, enabled, url, update_interval, fetch_via(direct|proxy), ua, hwid, device_os, ver_os, device_model, list header, format, list include/exclude/filter_proto/filter_country, dedup, expire_alert_days.
 - `config node`: name, enabled, uri, mux, mux_concurrency, xudp_concurrency, xudp_udp443, sockopt_mark, tcp_fast_open, tcp_keepalive_idle.

openwrt/shater-core/files/etc/config/shater

@@ -23,6 +23,32 @@ config globals 'globals'
 	option kill_switch 'closed'
 	# There is no dns_mode option: routing is decided by in-engine rule-sets and
 	# fake-IP is a resolver type (`config resolver` with type=fakeip + pool).
+	#
+	# Force ALL LAN plaintext DNS (:53) into the engine, INCLUDING queries the
+	# client sends to the router itself (the address DHCP hands out). ON by
+	# default: with it off, a client using the router as its resolver is answered
+	# by dnsmasq and forwarded to the ISP in the clear — no blocklists, no
+	# per-device DNS rules, no resolver detour — while a client that hard-codes
+	# 8.8.8.8 IS intercepted. The obedient client leaked; the evader did not.
+	#
+	# Set to '0' to opt out (dnsmasq answers router-addressed :53 again). Your
+	# explicit value is never overwritten: this file is a conffile, and the daemon
+	# always writes the option back as '1'/'0'.
+	#
+	# .lan and the private reverse (PTR) zones keep working: with at least one
+	# `config resolver` present the engine gets a synthetic server pointed at
+	# dnsmasq on 127.0.0.1:53 plus a rule that sends those suffixes to it; with no
+	# resolver at all the engine falls back to the system resolver, which is
+	# dnsmasq too. If you changed dnsmasq's domain away from `lan`, add a
+	# `config dns_rule` for it (only `lan` + RFC6303 reverse zones are built in).
+	#
+	# While the engine is DOWN the LAN is NOT left without DNS: the fail-closed
+	# holding plane hooks `forward` only, so dnsmasq still answers router-addressed
+	# :53 — unfiltered and in the clear, the documented trade-off (blocking it
+	# would also cut the daemon's own name resolution and its chance to recover).
+	# Queries aimed at an EXTERNAL resolver are dropped with the rest of the LAN's
+	# forwarded traffic.
+	option dns_intercept '1'
 	option ipv6 '1'
 	# Reserved fwmark base and routing-table base (do not overlap fw4/other apps).
 	option fwmark_base '0x2000'

panel/src/App.css

@@ -262,6 +262,91 @@
   }
 }
 
+/* ---- commit-confirm band (every page except Apply, which has the full panel) ----
+   Same plate as the protection banner so the two read as one family; the seconds
+   are the loud element because they are the only thing that is running out. */
+.cfm-band {
+  display: flex;
+  align-items: center;
+  gap: calc(var(--u, 8px) * 1.5);
+  margin-top: calc(var(--u, 8px) * 2);
+  padding: 10px 14px;
+  border: 1px solid color-mix(in srgb, var(--amber) 50%, var(--groove));
+  border-radius: 9px;
+  background: linear-gradient(180deg, color-mix(in srgb, var(--amber) 10%, var(--raised)), var(--raised));
+  box-shadow: 0 1px 0 var(--edge) inset;
+}
+.cfm-band-count {
+  display: flex;
+  align-items: baseline;
+  gap: 2px;
+  flex-shrink: 0;
+  font-family: var(--font-mono);
+  color: var(--amber);
+}
+.cfm-band-num {
+  font-size: 22px;
+  font-weight: 700;
+  font-variant-numeric: tabular-nums;
+  line-height: 1;
+}
+.cfm-band-unit {
+  font-size: 11px;
+  letter-spacing: 0.06em;
+}
+.cfm-band-copy {
+  flex: 1;
+  min-width: 0;
+  display: flex;
+  flex-direction: column;
+  gap: 3px;
+}
+.cfm-band-headline {
+  font-family: var(--font-mono);
+  font-size: 12.5px;
+  font-weight: 700;
+  letter-spacing: 0.02em;
+  color: var(--ink);
+}
+.cfm-band-detail {
+  font-size: 12.5px;
+  line-height: 1.5;
+  color: var(--dim);
+  max-width: 76ch;
+}
+.cfm-band-actions {
+  display: flex;
+  align-items: center;
+  gap: calc(var(--u, 8px) * 1);
+  flex-shrink: 0;
+}
+.cfm-band-link {
+  padding: 6px 11px;
+  border: 1px solid var(--groove);
+  border-radius: 6px;
+  font-family: var(--font-mono);
+  font-size: 11px;
+  letter-spacing: 0.06em;
+  text-transform: uppercase;
+  text-decoration: none;
+  color: var(--ink);
+  background: var(--raised);
+}
+.cfm-band-link:hover {
+  border-color: var(--accent);
+  color: var(--accent);
+}
+
+@media (max-width: 720px) {
+  .cfm-band {
+    flex-wrap: wrap;
+  }
+  .cfm-band-actions {
+    width: 100%;
+    justify-content: flex-end;
+  }
+}
+
 /* ---- last-apply findings (Overview) ----
    Severity carries the colour; the accent is reserved for interactive controls. */
 .findings {

panel/src/App.tsx

@@ -1,12 +1,13 @@
 import './App.css'
 import { useCallback, useEffect, useState } from 'react'
-import { Faceplate, FaceplateHeader, Led, Module } from './components'
+import { Button, Faceplate, FaceplateHeader, Led, Module } from './components'
 import type { LedVariant } from './components'
-import { ApiError, MOCK, getStatus } from './api'
+import { ApiError, MOCK, confirm as apiConfirm, getStatus } from './api'
 import type { Status } from './api'
+import { usePendingConfirm } from './pendingConfirm'
 import { bootstrapSession } from './session'
 import { ROUTES, navigate, useRoute } from './router'
-import { protectionState } from './planeState'
+import { engineState, protectionState } from './planeState'
 import type { Route } from './router'
 import { Overview, Placeholder, Nodes, Routing, Apply, DNS, Devices, Targets, Settings, Profiles, Insights, Networks } from './pages'
 
@@ -100,11 +101,75 @@ export function App() {
     >
       <Nav route={route} />
       <PlaneBanner status={status} route={route} />
+      <ConfirmBand route={route} onChanged={() => void refreshStatus()} />
       <Page route={route} status={status} onStatusChange={() => void refreshStatus()} />
     </Faceplate>
   )
 }
 
+/**
+ * The commit-confirm countdown, on every page.
+ *
+ * The daemon arms an auto-rollback on EVERY apply, but only the Apply page ever
+ * said so: press Apply on Routing, read "Applied", walk away, and the router
+ * reverts a minute later with nothing on screen having mentioned it. This band
+ * carries that deadline — and the button that stops it — to wherever the operator
+ * actually is.
+ *
+ * Suppressed on Apply, which renders the full control room for the same window
+ * (and reads the same record, so a reload no longer loses the countdown there
+ * either).
+ */
+function ConfirmBand({ route, onChanged }: { route: Route; onChanged: () => void }) {
+  const armed = usePendingConfirm()
+  const [busy, setBusy] = useState(false)
+  const [error, setError] = useState<string | null>(null)
+
+  // Keeping the config is the only action offered here; rolling back early is a
+  // deliberate act with its own before/after readout, and that lives on Apply.
+  const keep = useCallback(async () => {
+    setBusy(true)
+    setError(null)
+    try {
+      const r = await apiConfirm()
+      if (r.error) setError(r.error)
+    } catch (e) {
+      setError(e instanceof Error ? e.message : 'request failed')
+    } finally {
+      setBusy(false)
+      onChanged()
+    }
+  }, [onChanged])
+
+  if (!armed || route === 'apply') return null
+
+  return (
+    <div className="cfm-band" role="alert">
+      <Led variant="amber" pulse />
+      <div className="cfm-band-count" role="timer" aria-label={`${armed.remaining} seconds until auto-rollback`}>
+        <span className="cfm-band-num">{armed.remaining}</span>
+        <span className="cfm-band-unit">s</span>
+      </div>
+      <div className="cfm-band-copy">
+        <span className="cfm-band-headline">This config is live but not kept</span>
+        <span className="cfm-band-detail">
+          {error
+            ? `Couldn’t keep it — ${error}. Try again, or open Apply.`
+            : 'Every apply arms an auto-rollback. Keep this config before the timer runs out, or the router reverts to the last-good one.'}
+        </span>
+      </div>
+      <div className="cfm-band-actions">
+        <Button variant="primary" onClick={() => void keep()} disabled={busy}>
+          {busy ? 'Keeping…' : 'Keep this config'}
+        </Button>
+        <a className="cfm-band-link" href="#/apply" onClick={() => navigate('apply')}>
+          Apply page
+        </a>
+      </div>
+    </div>
+  )
+}
+
 /**
  * The protection state, pinned under the nav on every page EXCEPT Overview
  * (which shows the same state as its own headline readout — see planeState.ts).
@@ -225,14 +290,30 @@ function StatusBar({ status }: { status: Status | null }) {
   )
 }
 
+/**
+ * The one lamp that is on screen no matter which page you are on.
+ *
+ * It used to read `status.running`, which the daemon hardcoded to `true` — so the
+ * "Offline" branch could never be reached and the plate said "Online" through an
+ * engine that had failed to start. It now asks {@link engineState}, whose whole
+ * job is to be able to answer "down", and refuses to guess when nothing has been
+ * reported: an unlit socket, not a green light.
+ */
 function masterIndicator(
   phase: Phase,
   status: Status | null,
 ): { label: string; variant: LedVariant; pulse?: boolean } {
   if (phase === 'loading' || !status) return { label: 'Linking', variant: 'off' }
-  if (status.running && status.active) return { label: 'Online', variant: 'on', pulse: true }
-  if (status.running) return { label: 'Standby', variant: 'amber' }
-  return { label: 'Offline', variant: 'crit' }
+  switch (engineState(status)) {
+    case 'down':
+      return { label: 'Engine down', variant: 'crit' }
+    case 'up':
+      return status.active
+        ? { label: 'Online', variant: 'on', pulse: true }
+        : { label: 'Standby', variant: 'amber' }
+    default:
+      return { label: 'Unknown', variant: 'off' }
+  }
 }
 
 function UnauthPlate() {

panel/src/api.ts

@@ -15,6 +15,7 @@
 // reachable instead via the Vite proxy in vite.config.ts (no flag ⇒ real fetch).
 
 import * as mock from './mock'
+import { armPendingConfirm, clearPendingConfirm, noteConfirmTimeout } from './pendingConfirm'
 
 // --- error type -------------------------------------------------------------
 
@@ -413,6 +414,16 @@ export interface GroupHealth {
  * `tag` is the engine-side outbound (`chain-<name>-h2`). Debugging and tooltips
  * only; it is never a label to put in front of a person.
  *
+ * ORDERED WALK — THE READING STOPS AT THE FIRST DEAD HOP. Hops are NOT measured
+ * independently, and never were measurable that way: hop 3 is dialled THROUGH
+ * hop 2, so probing hop 3 while hop 2 is down measures hop 2 a second time and
+ * learns nothing about hop 3. The daemon therefore walks the path in wire order
+ * and stops at the first hop that does not answer. Every hop below that one is
+ * left undialled and reported `state: "untested"` — no measurement exists —
+ * carrying {@link ChainHopBlock} in `blocked_by` to name the hop that stopped the
+ * walk. So a chain never reports a dead hop with a live hop below it; that shape
+ * is not a rare case, it is unreachable.
+ *
  * NODE HOP vs GROUP HOP. For `kind: "node"` the hop IS the measurement: `total`
  * is 1, the counters follow its own state, and `selected` is ''. For
  * `kind: "group"` the counters roll up that hop's per-hop member COPIES — the
@@ -425,9 +436,12 @@ export interface GroupHealth {
  * Invariants the daemon guarantees — never re-derive them, just read them:
  * `tested === alive + dead` and `alive + dead + untested === total`.
  *
- * `state` is a closed set. `untested` is NEVER "dead" and never "healthy": it
- * means nothing fresh enough is known, which for a used chain is seconds away
- * from resolving on its own. `age_seconds: -1` means the age is unknown.
+ * `state` is a closed set of THREE. `untested` is NEVER "dead" and never
+ * "healthy": it means nothing fresh enough is known. Without `blocked_by` that is
+ * a matter of timing — for a used chain it resolves on its own within seconds.
+ * With `blocked_by` it will not resolve until the named hop is fixed. There is no
+ * fourth state for that; the state stays `untested` because that is what it is.
+ * `age_seconds: -1` means the age is unknown.
  */
 export interface ChainHopHealth {
   /** 1-based WIRE order. Hop 1 is dialled first; see the note above. */
@@ -451,6 +465,43 @@ export interface ChainHopHealth {
   alive: number
   dead: number
   untested: number
+  /**
+   * PRESENT ONLY on a hop the ordered walk never reached — i.e. a hop sitting
+   * below one the prober found `dead`. The key is omitted otherwise; absent is
+   * the normal case and means "this hop was actually dialled".
+   *
+   * Its presence is the daemon's own statement that this hop has NO measurement,
+   * and it comes with the rest of that statement already filled in: `state` is
+   * `untested`, `delay_ms` is 0, `age_seconds` is -1, and the counters are
+   * `alive: 0, dead: 0, tested: 0, untested: total`. Read those; do not re-derive
+   * a verdict from them, and do not infer a block from zeroed counters either —
+   * an unprobed-yet hop has the same numbers and a very different meaning.
+   * `selected` MAY still be non-empty: the wrapper does have a pick, it simply
+   * was not measured, so it says which node the hop would use, not which node is
+   * carrying traffic.
+   */
+  blocked_by?: ChainHopBlock
+}
+
+/**
+ * The hop that stopped the ordered walk, as reported on every hop below it.
+ *
+ * This exists because "no reading" and "no reading, and here is whose fault that
+ * is" are different answers to the operator's actual question. Without it a
+ * blocked hop is indistinguishable from one the observatory has not come round to
+ * yet, and the interface can only shrug.
+ *
+ * `index` is the 1-based WIRE index of the blocking hop and is ALWAYS smaller
+ * than the index of the hop carrying it, so it points at a hop already on screen.
+ * `tag` is that hop's engine outbound (`chain-<name>-h3`) — debugging and
+ * tooltips only, never a label to put in front of a person, exactly as on
+ * {@link ChainHopHealth}.tag.
+ */
+export interface ChainHopBlock {
+  /** 1-based wire index of the hop that did not answer. Always < this hop's index. */
+  index: number
+  /** That hop's engine outbound tag — tooltips/debugging, never a label. */
+  tag: string
 }
 
 /** Per-chain reachability, the chain analogue of {@link GroupHealth}.used (plan
@@ -1126,8 +1177,13 @@ export function getStatus(): Promise<Status> {
   return MOCK ? mock.getStatus() : req<Status>('api/status')
 }
 
-export function getConfig(): Promise<Model> {
-  return MOCK ? mock.getConfig() : req<Model>('api/config')
+export async function getConfig(): Promise<Model> {
+  const m = await (MOCK ? mock.getConfig() : req<Model>('api/config'))
+  // Every page reads the config, and the commit-confirm window's length is the
+  // only thing needed to arm a countdown — so it is captured here once instead of
+  // being threaded through eight pages. See pendingConfirm.ts.
+  noteConfirmTimeout(m.Globals?.ConfirmTimeout)
+  return m
 }
 
 export function putConfig(m: Model): Promise<{ ok: boolean; applied: boolean }> {
@@ -1136,16 +1192,32 @@ export function putConfig(m: Model): Promise<{ ok: boolean; applied: boolean }>
     : req('api/config', { method: 'PUT', body: JSON.stringify(m) })
 }
 
-export function apply(): Promise<ApplyResult> {
-  return MOCK ? mock.apply() : req<ApplyResult>('api/apply', { method: 'POST' })
+/**
+ * POST /api/apply.
+ *
+ * The daemon arms an auto-rollback on EVERY successful apply that changed
+ * something (panel/api.go handleApply → ArmRollback), whichever page's button was
+ * pressed. Recording it here — the one place every one of those buttons goes
+ * through — is what lets the countdown and the "Keep this config" control follow
+ * the operator around the panel instead of living in the Apply page's local
+ * state. See pendingConfirm.ts.
+ */
+export async function apply(): Promise<ApplyResult> {
+  const r = await (MOCK ? mock.apply() : req<ApplyResult>('api/apply', { method: 'POST' }))
+  if (!r.error && r.changed) armPendingConfirm()
+  return r
 }
 
-export function confirm(): Promise<ApplyResult> {
-  return MOCK ? mock.confirm() : req<ApplyResult>('api/confirm', { method: 'POST' })
+export async function confirm(): Promise<ApplyResult> {
+  const r = await (MOCK ? mock.confirm() : req<ApplyResult>('api/confirm', { method: 'POST' }))
+  if (!r.error) clearPendingConfirm()
+  return r
 }
 
-export function rollback(): Promise<ApplyResult> {
-  return MOCK ? mock.rollback() : req<ApplyResult>('api/rollback', { method: 'POST' })
+export async function rollback(): Promise<ApplyResult> {
+  const r = await (MOCK ? mock.rollback() : req<ApplyResult>('api/rollback', { method: 'POST' }))
+  if (!r.error) clearPendingConfirm()
+  return r
 }
 
 export function getStats(): Promise<Stats> {

panel/src/components/Clock.tsx

@@ -1,11 +1,49 @@
 import { useEffect, useState } from 'react'
 
+/**
+ * The panel's wall clock, in the SAME timezone as every timestamp under it.
+ *
+ * It used to read `getUTCHours()` and print "UTC", while `format.ts` renders every
+ * log line, connection event and date through `toLocaleTimeString` — i.e. the
+ * browser's zone. In Moscow that put two clocks three hours apart on one plate,
+ * and the header was the one nobody could reconcile: the router's "started" time
+ * read later than the current time while the uptime said it had been up for hours.
+ *
+ * So the clock follows the rest of the panel — local, and it SAYS which offset
+ * that is, because a bare "12:41:07" beside a router in another zone is the
+ * ambiguity that started this. The zone label is the browser's UTC offset, not an
+ * abbreviation: "MSK"/"CEST" are not derivable everywhere, an offset always is.
+ *
+ * This is the BROWSER's clock, not the router's — the appliance has no RTC. Every
+ * router-sourced instant in the panel is converted to this clock before it is
+ * shown, which is what makes one label at the top honest for the whole page.
+ */
+function zoneLabel(d: Date): string {
+  // getTimezoneOffset() is minutes WEST of UTC, so the sign is inverted.
+  const min = -d.getTimezoneOffset()
+  if (min === 0) return 'UTC'
+  const sign = min < 0 ? '−' : '+'
+  const a = Math.abs(min)
+  const h = Math.floor(a / 60)
+  const m = a % 60
+  return `UTC${sign}${h}${m ? `:${String(m).padStart(2, '0')}` : ''}`
+}
+
 function format(d: Date): string {
   const p = (n: number) => String(n).padStart(2, '0')
-  return `${p(d.getUTCHours())}:${p(d.getUTCMinutes())}:${p(d.getUTCSeconds())} UTC`
+  return `${p(d.getHours())}:${p(d.getMinutes())}:${p(d.getSeconds())} ${zoneLabel(d)}`
 }
 
-/** Live UTC readout, tabular digits, ticking once a second. */
+/** The full zone name, for the title — "Europe/Moscow" says more than "+3" does. */
+function zoneName(): string {
+  try {
+    return Intl.DateTimeFormat().resolvedOptions().timeZone || ''
+  } catch {
+    return ''
+  }
+}
+
+/** Live local readout, tabular digits, ticking once a second. */
 export function Clock({ className }: { className?: string }) {
   const [now, setNow] = useState(() => format(new Date()))
 
@@ -14,5 +52,13 @@ export function Clock({ className }: { className?: string }) {
     return () => window.clearInterval(id)
   }, [])
 
-  return <span className={['clock', className].filter(Boolean).join(' ')}>{now}</span>
+  const zone = zoneName()
+  return (
+    <span
+      className={['clock', className].filter(Boolean).join(' ')}
+      title={zone ? `Your device's clock — ${zone}. Every time in the panel is shown in this zone.` : undefined}
+    >
+      {now}
+    </span>
+  )
 }

panel/src/format.ts

@@ -77,6 +77,39 @@ export function fmtDateTime(unix: number): string {
   return d && t ? `${d}, ${t}` : d || t
 }
 
+// --- remote-list freshness ---------------------------------------------------
+// A url/geo-sourced list re-fetches on a cadence and the engine reports when it
+// last pulled (GET /api/ruleset/status). Routing shows this for rule-sets and DNS
+// shows it for blocklists, so the two readings live here and cannot drift apart.
+
+/** "updated 3h ago" / "never updated" for a remote list's last fetch (RFC3339). */
+export function relFetch(iso: string): string {
+  if (!iso) return 'never updated'
+  const t = Date.parse(iso)
+  if (Number.isNaN(t)) return 'never updated'
+  const s = Math.max(0, Math.floor((Date.now() - t) / 1000))
+  if (s < 45) return 'updated just now'
+  const m = Math.floor(s / 60)
+  if (m < 60) return `updated ${m}m ago`
+  const h = Math.floor(m / 60)
+  if (h < 24) return `updated ${h}h ago`
+  const d = Math.floor(h / 24)
+  return `updated ${d}d ago`
+}
+
+/** "every 24h" for an auto-update cadence in seconds ("" when there is none). */
+export function everyLabel(sec: number): string {
+  if (!sec || sec <= 0) return ''
+  if (sec % 3600 === 0) {
+    const h = sec / 3600
+    if (h < 48) return `every ${h}h`
+    if (sec % 86400 === 0) return `every ${sec / 86400}d`
+    return `every ${h}h`
+  }
+  if (sec % 60 === 0) return `every ${sec / 60}m`
+  return `every ${sec}s`
+}
+
 /**
  * A coarse "how long until / since" reading for a unix deadline, relative to now.
  *

panel/src/mock.ts

@@ -194,6 +194,7 @@ const CONFIG: Model = {
   // to an official remote list; the others are the usual url / inline lists.
   Blocklists: [
     { Name: 'StevenBlack', Enabled: true, Source: 'url', URL: 'https://raw.githubusercontent.com/StevenBlack/hosts/master/hosts', Response: 'nxdomain', UpdateInterval: '24h' },
+    { Name: 'oisd-basic', Enabled: true, Source: 'url', URL: 'https://big.oisd.nl/domainswild', Response: 'nxdomain', UpdateInterval: '24h' },
     { Name: 'telegram-block', Enabled: false, Source: 'geosite', Categories: ['telegram'], Response: 'nxdomain', UpdateInterval: '24h' },
   ],
   Resolvers: [
@@ -323,6 +324,24 @@ const RULESET_STATUS: RulesetStatus[] = [
     rule_count: 903,
   },
   { tag: 'rs-ru-geoip-ru', name: 'ru-geoip', category: 'ru', kind: 'ruleset', remote: true, last_updated: '', interval_seconds: 86_400, rule_count: 0 },
+  // Blocklists report through the same endpoint under `bl-<name>`, which the DNS
+  // page never asked for — so a list that has NEVER been fetched still read
+  // "filtering". StevenBlack is that case here; oisd-basic is the healthy one, so
+  // both readings are exercisable offline.
+  { tag: 'bl-StevenBlack', name: 'StevenBlack', category: '', kind: 'blocklist', remote: true, last_updated: '', interval_seconds: 86_400, rule_count: 0 },
+  {
+    tag: 'bl-oisd-basic',
+    name: 'oisd-basic',
+    category: '',
+    kind: 'blocklist',
+    remote: true,
+    last_updated: new Date(Date.now() - 6 * 3600_000).toISOString(),
+    interval_seconds: 86_400,
+    rule_count: 218_431,
+  },
+  // Disabled in CONFIG, so the row reads "off" whatever this says — it exists to
+  // prove the row does not start claiming things the moment a status appears.
+  { tag: 'bl-telegram-block-telegram', name: 'telegram-block', category: 'telegram', kind: 'blocklist', remote: true, last_updated: '', interval_seconds: 86_400, rule_count: 0 },
 ]
 
 /** GET /api/rules/reachability. Mirrors the daemon's analysis over CONFIG.Rules:
@@ -1199,14 +1218,19 @@ function healthList(): GroupHealth[] {
  * Per-hop health, keyed by chain name — what the observatory measured at each
  * position of the path, in WIRE order.
  *
- * `ewan-wg-subs` is the fixture that matters. Its hop 1 is the AmneziaWG node and
- * answers; hops 2 and 4 are subscription groups that answer THROUGH it; hop 3 is
- * a group whose members all time out at that position. Note that hop 4 rolls up
- * `via-tunnel`, the same group whose standalone card reads 0 of 6 alive — alive
- * as a hop, dead on its own, both true, because they measure different dial
- * paths. That contradiction is the whole point of measuring per hop.
+ * `ewan-wg-subs` is the fixture that matters, and it encodes the ORDERED WALK.
+ * Hop 1 is the WireGuard node and answers; hop 2 is a subscription group whose
+ * copies answer THROUGH it — 119 of 122 tested alive, which is the reading only a
+ * per-hop probe can produce, since the same members are dialled differently on
+ * their own card. Hop 3 is a group whose members all time out at that position,
+ * and the walk STOPS there: hop 4 is dialled through hop 3, so it was never
+ * dialled at all. It comes back `untested` with `blocked_by` naming hop 3, its
+ * counters zeroed, and `selected` still set — the wrapper has a pick, nothing
+ * crossed it to measure. A dead hop with a live hop under it is not in this
+ * fixture because the daemon can no longer produce one.
  *
- * `sub-fresh` is used but never yet reached: every hop untested, nothing dead.
+ * `sub-fresh` is used but never yet reached: every hop untested, nothing dead,
+ * no block — the other reason a lamp is unlit, and the one that fixes itself.
  * `relay` is absent from this map on purpose — an unused chain is never
  * materialised, so the daemon sends no `hops` key at all, which is "nothing
  * measured", not "no hops".
@@ -1215,8 +1239,8 @@ const CHAIN_HOPS: Record<string, ChainHopHealth[]> = {
   'ewan-wg-subs': [
     { index: 1, tag: 'chain-ewan-wg-subs-h1', kind: 'node', exit: false, state: 'alive', delay_ms: 41, age_seconds: 22, selected: '', total: 1, tested: 1, alive: 1, dead: 0, untested: 0 },
     { index: 2, tag: 'chain-ewan-wg-subs-h2', kind: 'group', exit: false, state: 'alive', delay_ms: 96, age_seconds: 18, selected: '🇳🇱 Amsterdam-01', total: 298, tested: 122, alive: 119, dead: 3, untested: 176 },
-    { index: 3, tag: 'chain-ewan-wg-subs-h3', kind: 'group', exit: false, state: 'dead', delay_ms: 0, age_seconds: 15, selected: '', total: 24, tested: 24, alive: 0, dead: 24, untested: 0 },
-    { index: 4, tag: 'chain-ewan-wg-subs-h4', kind: 'group', exit: true, state: 'alive', delay_ms: 148, age_seconds: 19, selected: '🇸🇬 Singapore-09', total: 6, tested: 6, alive: 6, dead: 0, untested: 0 },
+    { index: 3, tag: 'chain-ewan-wg-subs-h3', kind: 'group', exit: false, state: 'dead', delay_ms: 0, age_seconds: 15, selected: '', total: 2, tested: 2, alive: 0, dead: 2, untested: 0 },
+    { index: 4, tag: 'chain-ewan-wg-subs-h4', kind: 'group', exit: true, state: 'untested', delay_ms: 0, age_seconds: -1, selected: '🇸🇬 Singapore-09', total: 6, tested: 0, alive: 0, dead: 0, untested: 6, blocked_by: { index: 3, tag: 'chain-ewan-wg-subs-h3' } },
   ],
   'sub-fresh': [
     { index: 1, tag: 'chain-sub-fresh-h1', kind: 'node', exit: false, state: 'untested', delay_ms: 0, age_seconds: -1, selected: '', total: 1, tested: 0, alive: 0, dead: 0, untested: 1 },
@@ -1240,8 +1264,9 @@ function chainHealthList(): ChainHealth[] {
 
 /** A chain is "used" when some enabled routing rule (or Final, or a DNS detour)
  *  targets `chain:<name>` — the same reachability the daemon's observatory derives.
- *  The mock's rules never target a chain, so every chain reads used=false; a real
- *  config would mark the ones rules point at used=true. */
+ *  Two of the mock's rules do (`media-via-chain` → ewan-wg-subs, `spare-via-chain`
+ *  → sub-fresh), so those two chains read used=true and get a hop rail; `relay`
+ *  is targeted by nothing and reads used=false, which is the unused note. */
 function chainUsed(name: string): boolean {
   const target = `chain:${name}`
   return (CONFIG.Rules ?? []).some(
@@ -1328,17 +1353,20 @@ const GROUP_TEST_SHAPE: Record<string, Omit<GroupTestResult, 'group' | 'tested_u
     error: '',
   },
   // The chain, and the pairing that makes the whole feature worth building. A
-  // chain is one series path, so with hop 3 dead the end-to-end probe CANNOT
-  // succeed — this row and the hop rail have to tell one story, not two. The
-  // row says the path is down; the rail says which of the four hops did it,
-  // which is the part nobody could see before.
+  // chain is one series path, so with hop 3 dead the end-to-end probe is never
+  // even attempted — the daemon stops walking there. This row and the hop rail
+  // therefore have to tell one story, not two: both name hop 3, and neither
+  // offers hop 4 as a second suspect. Note the row does NOT say "the probe
+  // failed" — no probe of this chain's exit ran at all — which is why the daemon
+  // has a separate message for it.
   'ewan-wg-subs': {
     selected: '',
     delay_ms: 0,
     exit_ip: '',
     exit_country: '',
     ok: false,
-    error: 'the observatory’s probe through this path failed',
+    error:
+      'hop 3 of this chain was probed and did not answer, so nothing reaches the exit through it — fix that hop first',
   },
   // The one real health failure in the fixture: the observatory's probe ran along
   // this path and did not come back.

panel/src/pages/Apply.tsx

@@ -11,6 +11,8 @@ import {
   ApiError,
 } from '../api'
 import type { Globals, Status } from '../api'
+import { engineReadout } from '../planeState'
+import { onPendingConfirmExpire, usePendingConfirm } from '../pendingConfirm'
 
 // Short, readable config hash — drops the "sha256:" prefix like the footer does.
 function short(hash: string): string {
@@ -25,13 +27,6 @@ function msg(e: unknown): string {
 
 type Busy = 'apply' | 'confirm' | 'rollback' | null
 
-/** A pending commit-confirm window: the daemon has armed an auto-rollback. */
-interface Armed {
-  total: number // the ConfirmTimeout the window started with
-  remaining: number // seconds left before the daemon reverts
-  appliedHash: string // the hash that went live on apply (the "after" of apply)
-}
-
 type ActionKind = 'apply' | 'confirm' | 'rollback' | 'expire'
 interface ActionResult {
   kind: ActionKind
@@ -57,7 +52,11 @@ export default function Apply() {
   const [configError, setConfigError] = useState<string | null>(null)
 
   const [busy, setBusy] = useState<Busy>(null)
-  const [armed, setArmed] = useState<Armed | null>(null)
+  // The armed window is app-wide state, not this page's: it is recorded by the
+  // api layer on every apply and survives a reload. Keeping it local is what made
+  // refreshing this tab lose both the countdown and the only button that could
+  // stop it. See pendingConfirm.ts.
+  const armed = usePendingConfirm()
   const [result, setResult] = useState<ActionResult | null>(null)
   const [confirmingRollback, setConfirmingRollback] = useState(false)
 
@@ -104,14 +103,16 @@ export default function Apply() {
     void loadConfig()
   }, [loadConfig])
 
-  // ---- commit-confirm countdown: a calm 1s numeric tick, effect-scoped so the
-  // timer is always cleared on unmount / confirm / rollback (no leaked intervals) ----
-  useEffect(() => {
-    if (!armed) return
-    if (armed.remaining <= 0) {
-      // Window elapsed — the daemon reverts to last-good on its own. Observe it.
-      const before = armed.appliedHash
-      setArmed(null)
+  // The window running out is the daemon reverting on its own — observe it and
+  // say so. The countdown itself ticks inside usePendingConfirm; this only reacts
+  // to the end of it, and the store makes sure that fires exactly once even with
+  // the app-wide band mounted alongside.
+  const liveHashRef = useRef('')
+  liveHashRef.current = status?.hash ?? ''
+  useEffect(
+    () =>
+      onPendingConfirmExpire(() => {
+        const before = liveHashRef.current
         flash('Auto-rolled back')
         void (async () => {
           const after = (await refreshStatus())?.hash ?? ''
@@ -123,13 +124,9 @@ export default function Apply() {
             after,
           })
         })()
-      return
-    }
-    const id = window.setTimeout(() => {
-      setArmed((a) => (a ? { ...a, remaining: a.remaining - 1 } : a))
-    }, 1000)
-    return () => window.clearTimeout(id)
-  }, [armed, flash, refreshStatus])
+      }),
+    [flash, refreshStatus],
+  )
 
   const confirmWindow = globals?.ConfirmTimeout ?? 0
 
@@ -146,8 +143,9 @@ export default function Apply() {
         return
       }
       const after = (await refreshStatus())?.hash ?? before
+      // The window itself was recorded by api.apply(); this branch only writes the
+      // readout for it.
       if (r.changed && confirmWindow > 0) {
-        setArmed({ total: confirmWindow, remaining: confirmWindow, appliedHash: after })
         setResult({
           kind: 'apply',
           tone: 'good',
@@ -179,7 +177,8 @@ export default function Apply() {
   const doConfirm = useCallback(async () => {
     const before = status?.hash ?? ''
     setBusy('confirm')
-    setArmed(null) // stop the countdown immediately; confirm cancels the auto-rollback
+    // api.confirm() clears the shared window on success — the countdown stops the
+    // moment the daemon agrees, not the moment we asked.
     try {
       const r = await apiConfirm()
       if (r.error) {
@@ -208,7 +207,7 @@ export default function Apply() {
     const before = status?.hash ?? ''
     setConfirmingRollback(false)
     setBusy('rollback')
-    setArmed(null) // rolling back also cancels any pending confirm window
+    // api.rollback() clears the shared window on success (rolling back ends it).
     try {
       const r = await apiRollback()
       if (r.error) {
@@ -237,19 +236,26 @@ export default function Apply() {
   }, [status, flash, refreshStatus])
 
   // ---- derived display state (mirrors Overview's LED semantics) ----
-  const killArmed = globals ? globals.KillSwitch === 'closed' : false
-  const engineVariant: LedVariant = !status
-    ? 'off'
-    : status.running && status.active
-      ? 'on'
-      : status.running
-        ? 'amber'
-        : 'crit'
-  const dataVariant: LedVariant = status?.table ? 'on' : status?.running ? 'amber' : 'off'
+  //
+  // The LIVE kill-switch wins over the saved one, exactly as on Overview: this row
+  // is a status readout, and the config on disk can already differ from what is
+  // installed. Falls back to the config only while /api/status is unread.
+  const killArmed = (status?.kill_switch ?? globals?.KillSwitch ?? 'closed') === 'closed'
+  // Every engine mark on this page comes from ONE reading, and that reading is
+  // able to say "stopped" — see planeState.engineState for why `status.running`
+  // could not. This page is where someone lands when the network is down; three
+  // green lamps here were the difference between "I broke it" and "nothing broke".
+  const engine = engineReadout(status)
+  const engineVariant: LedVariant = engine.variant
+  // No nft table means there is no data plane at all. Under a fail-closed switch
+  // that is a leak (crit); under an open one it is the documented choice (amber).
+  // It used to go amber whenever `running` was true — i.e. always — and unlit
+  // otherwise, so the one state worth shouting about had no colour of its own.
+  const dataVariant: LedVariant = status?.table ? 'on' : !status ? 'off' : killArmed ? 'crit' : 'amber'
   const configVariant: LedVariant = status?.enabled ? 'on' : 'amber'
 
   const liveHash = short(status?.hash ?? '')
-  const pct = armed ? Math.max(0, Math.round((armed.remaining / armed.total) * 100)) : 0
+  const pct = armed ? Math.max(0, Math.round((armed.remaining / armed.pending.total) * 100)) : 0
 
   // Only offer rollback when the daemon says one would revert something: an armed
   // commit-confirm snapshot, or an engine last-good predecessor. When false there
@@ -264,9 +270,7 @@ export default function Apply() {
           label="Engine"
           variant={engineVariant}
           pulse={engineVariant === 'on'}
-          value={
-            !status ? 'checking…' : status.running ? (status.active ? 'active' : 'idle') : 'stopped'
-          }
+          value={engine.word}
         />
         <StatusPip
           label="Config"
@@ -310,8 +314,12 @@ export default function Apply() {
           unit="· sha256"
           led={{ variant: configVariant }}
           rows={[
-            { k: 'engine', v: status?.running ? 'running' : 'stopped', hot: !status?.running },
-            { k: 'data plane', v: status?.table ? 'nft installed' : 'no table' },
+            { k: 'engine', v: engine.word, hot: engineVariant === 'crit' },
+            {
+              k: 'data plane',
+              v: status?.table ? 'nft installed' : 'no table',
+              hot: dataVariant === 'crit',
+            },
             { k: 'kill-switch', v: killArmed ? 'fail-closed' : 'open', hot: !killArmed },
           ]}
         />
@@ -325,7 +333,7 @@ export default function Apply() {
           }
           led={{ variant: engineVariant }}
           rows={[
-            { k: 'state', v: !status ? 'checking…' : status.active ? 'active' : 'idle' },
+            { k: 'state', v: engine.word, hot: engineVariant === 'crit' },
             { k: 'config', v: status?.enabled ? 'enabled' : 'disabled' },
             { k: 'schema', v: globals ? `v${globals.SchemaVersion}` : '—' },
           ]}
@@ -362,9 +370,12 @@ export default function Apply() {
             </div>
             <div className="cc-info">
               <p className="cc-copy">
-                Applied config <span className="mono">{short(armed.appliedHash)}</span> is live but
-                not yet kept. Confirm to keep it — otherwise the daemon rolls back to the last-good
-                config when the timer hits zero.
+                {/* The live hash IS the applied one while a window is open — that
+                    is what "live but not kept" means — so the readout survives a
+                    reload instead of depending on what this tab remembers. */}
+                Applied config <span className="mono">{liveHash}</span> is live but not yet kept.
+                Confirm to keep it — otherwise the daemon rolls back to the last-good config when
+                the timer hits zero.
               </p>
               <div className="cc-bar" aria-hidden="true">
                 <span className="cc-bar-fill" style={{ width: `${pct}%` }} />

panel/src/pages/DNS.css

@@ -387,6 +387,79 @@
 .dns-row-state[data-active='on'] {
   color: var(--led-on);
 }
+/* A list that is switched on but has nothing loaded is not "off" and is certainly
+   not "filtering" — warn semantics, the same amber the badges use. */
+.dns-row-state[data-active='warn'] {
+  color: var(--amber);
+}
+
+/* ---- remote-list freshness (mirrors the rule-set rows on Routing) ---- */
+.dns-row-sync {
+  display: flex;
+  align-items: center;
+  flex-wrap: wrap;
+  gap: 10px;
+  margin-top: 3px;
+}
+.dns-sync-fresh {
+  font-family: var(--font-mono);
+  font-size: 11px;
+  color: var(--dim);
+}
+.dns-sync-fresh[data-never='y'] {
+  color: var(--amber);
+}
+.dns-sync-every,
+.dns-sync-rules {
+  font-family: var(--font-mono);
+  font-size: 10.5px;
+  letter-spacing: 0.02em;
+  color: var(--faint);
+}
+.dns-sync-every::before {
+  content: '↻ ';
+}
+.dns-sync-update {
+  display: inline-flex;
+  align-items: center;
+  gap: 6px;
+  padding: 3px 10px;
+  border: 1px solid var(--accent-soft);
+  border-radius: 5px;
+  background: var(--raised);
+  color: var(--accent);
+  font-family: var(--font-mono);
+  font-size: 10px;
+  letter-spacing: var(--track-label);
+  text-transform: uppercase;
+  cursor: pointer;
+  transition: color 0.12s, border-color 0.12s, background 0.12s;
+}
+.dns-sync-update:hover:not(:disabled) {
+  border-color: var(--accent);
+  background: color-mix(in srgb, var(--accent) 12%, transparent);
+}
+.dns-sync-update:focus-visible {
+  outline: 2px solid var(--accent);
+  outline-offset: 2px;
+}
+.dns-sync-update:disabled {
+  opacity: 0.6;
+  cursor: not-allowed;
+}
+.dns-sync-spin {
+  width: 10px;
+  height: 10px;
+  border: 2px solid color-mix(in srgb, var(--accent) 35%, transparent);
+  border-top-color: var(--accent);
+  border-radius: 50%;
+  animation: dns-sync-spin 0.7s linear infinite;
+}
+@keyframes dns-sync-spin {
+  to {
+    transform: rotate(360deg);
+  }
+}
 
 /* badge — groove-bordered, not orange (accent stays reserved) */
 .dns-badge {
@@ -646,9 +719,15 @@
   .dns-skel {
     animation: none;
   }
+  /* No spin under reduced motion — the static ring + "Updating…" label carry it. */
+  .dns-sync-spin {
+    animation: none;
+    border-top-color: color-mix(in srgb, var(--accent) 35%, transparent);
+  }
   .dns-chip,
   .dns-input,
-  .dns-seg-btn {
+  .dns-seg-btn,
+  .dns-sync-update {
     transition: none;
   }
 }

panel/src/pages/DNS.tsx

@@ -1,8 +1,16 @@
 import './DNS.css'
 import { useCallback, useEffect, useMemo, useRef, useState } from 'react'
 import { Button, CatSuggest, Led, SrcPicker, Toggle, useConfirm } from '../components'
-import { apply as apiApply, getConfig, putConfig, ApiError } from '../api'
-import type { Alert, DNSRule, Model, Resolver } from '../api'
+import {
+  apply as apiApply,
+  getConfig,
+  getRulesetStatus,
+  putConfig,
+  updateRuleset as apiUpdateRuleset,
+  ApiError,
+} from '../api'
+import type { Alert, DNSRule, Model, Resolver, RulesetStatus } from '../api'
+import { everyLabel, relFetch } from '../format'
 
 // The DNS / Blocklists page is a thin editor over the desired-state Model —
 // exactly like Nodes.tsx. Every edit rewrites the relevant slice in-place, PUTs
@@ -310,6 +318,68 @@ export default function DNS() {
     [config],
   )
 
+  // ---- did the lists actually LOAD? -----------------------------------------
+  //
+  // A blocklist row said "filtering" whenever the list and the master switch were
+  // both on. Neither of those is evidence that anything is being blocked: a
+  // url/geosite list is fetched by the engine, the daemon treats a failed fetch as
+  // a CRITICAL apply finding, and the row went on saying "filtering" through it.
+  // The Routing page had already been given this reading for rule-sets — the same
+  // endpoint, the same tags (`bl-<name>` / `al-<name>`) — and the DNS page never
+  // asked. Slow poll: lists refresh on a ~24h cadence, so 15s only has to catch a
+  // manual Update-now. Grouped by NAME because a geosite list with N categories
+  // reports N records.
+  const [listStatus, setListStatus] = useState<Map<string, RulesetStatus[]>>(new Map())
+  const [updatingLists, setUpdatingLists] = useState<Set<string>>(new Set())
+  const loadListStatus = useCallback(async () => {
+    try {
+      const all = await getRulesetStatus()
+      const m = new Map<string, RulesetStatus[]>()
+      for (const s of all) {
+        if (s.kind !== 'blocklist' && s.kind !== 'allowlist') continue
+        const key = `${s.kind}:${s.name}`
+        const arr = m.get(key)
+        if (arr) arr.push(s)
+        else m.set(key, [s])
+      }
+      setListStatus(m)
+    } catch {
+      // Engine stopped or an older daemon — keep the last reading. The row falls
+      // back to "load not reported", which claims nothing either way.
+    }
+  }, [])
+  useEffect(() => {
+    void loadListStatus()
+    const id = window.setInterval(() => void loadListStatus(), 15000)
+    return () => window.clearInterval(id)
+  }, [loadListStatus])
+
+  const updateList = useCallback(
+    async (kind: 'blocklist' | 'allowlist', name: string) => {
+      const key = `${kind}:${name}`
+      setUpdatingLists((prev) => new Set(prev).add(key))
+      try {
+        // One geo list can hold several categories, each its own engine tag.
+        const recs = listStatus.get(key) ?? []
+        const tags = recs.length
+          ? recs.map((r) => r.tag)
+          : [`${kind === 'blocklist' ? 'bl' : 'al'}-${name}`]
+        for (const tag of tags) await apiUpdateRuleset(tag)
+        await loadListStatus()
+        flash(`${name} refreshed`)
+      } catch (e) {
+        flash(`Refresh failed — ${errText(e)}`)
+      } finally {
+        setUpdatingLists((prev) => {
+          const next = new Set(prev)
+          next.delete(key)
+          return next
+        })
+      }
+    },
+    [listStatus, loadListStatus, flash],
+  )
+
   const blOn = blocklists.filter((b) => b.Enabled).length
   const alOn = allowlists.filter((a) => a.Enabled).length
   const blNames = useMemo(() => new Set(blocklists.map((b) => b.Name)), [blocklists])
@@ -500,19 +570,58 @@ export default function DNS() {
     [config, resolvers, save],
   )
 
+  /**
+   * Delete a resolver, saying what it was still wired into.
+   *
+   * The three GLOBAL slots (default, fallback, endpoint) are cleared here, because
+   * a global pointing at nothing is never what anyone meant. The DNS RULES are a
+   * different matter: each one is a decision about which queries go where, and
+   * silently deleting or repointing them would change where a device's DNS goes
+   * without saying so. So they are named instead and left alone — the dialog is
+   * where the operator finds out they exist, which is precisely what this page
+   * used to skip: it cleared the two globals without a word and never mentioned
+   * the rules at all.
+   */
   const removeResolver = useCallback(
     async (idx: number) => {
       if (!config) return
       const target = resolvers[idx]
+      const g = { ...config.Globals }
+      const slots: string[] = []
+      if (g.ResolverDefault === target.Name) slots.push('the default resolver')
+      if (g.ResolverFallback === target.Name) slots.push('the fallback resolver')
+      if (g.EndpointResolver === target.Name) slots.push('the endpoint resolver')
+      const usedBy = dnsRules.filter((r) => r.Resolver === target.Name)
+
+      const parts: string[] = []
+      if (slots.length > 0) {
+        parts.push(
+          `It is ${slots.join(' and ')} — ${
+            slots.length === 1 ? 'that slot is' : 'those slots are'
+          } cleared, so DNS falls back to the engine's built-in resolution.`,
+        )
+      }
+      if (usedBy.length === 1) {
+        parts.push(
+          `One DNS rule still sends queries to it (order ${usedBy[0].Order}). It is left as it is and will have nowhere to resolve — repoint it before you apply.`,
+        )
+      } else if (usedBy.length > 1) {
+        parts.push(
+          `${usedBy.length} DNS rules still send queries to it (orders ${usedBy
+            .map((r) => r.Order)
+            .join(', ')}). They are left as they are and will have nowhere to resolve — repoint them before you apply.`,
+        )
+      }
+      if (parts.length === 0) parts.push('Nothing else in the config points at it.')
+
       const ok = await confirm({
         label: 'Delete resolver',
         title: `Delete resolver “${target.Name}”?`,
-        body: 'This removes it from the config.',
+        body: parts.join(' '),
       })
       if (!ok) return
       const next = resolvers.filter((_, i) => i !== idx)
-      // Don't leave default/fallback pointing at a resolver that no longer exists.
-      const g = { ...config.Globals }
+      // Don't leave default/fallback/endpoint pointing at a resolver that's gone.
       const cleared: string[] = []
       if (g.ResolverDefault === target.Name) {
         g.ResolverDefault = ''
@@ -522,12 +631,16 @@ export default function DNS() {
         g.ResolverFallback = ''
         cleared.push('fallback')
       }
+      if (g.EndpointResolver === target.Name) {
+        g.EndpointResolver = ''
+        cleared.push('endpoint')
+      }
       const msg = cleared.length
         ? `Deleted ${target.Name} — cleared ${cleared.join(' & ')}`
         : `Deleted ${target.Name}`
       void save({ ...config, Globals: g, Resolvers: next }, msg)
     },
-    [config, resolvers, save],
+    [config, resolvers, dnsRules, save, confirm],
   )
 
   const setResolverDefault = useCallback(
@@ -905,8 +1018,11 @@ export default function DNS() {
                 categories={b.Categories}
                 response={b.Response}
                 filterOn={dnsFilterOn}
+                statuses={listStatus.get(`blocklist:${b.Name}`) ?? null}
+                updating={updatingLists.has(`blocklist:${b.Name}`)}
                 busy={busy}
                 onToggle={(on) => toggleBlocklist(i, on)}
+                onUpdateNow={() => void updateList('blocklist', b.Name)}
                 onDelete={() => removeBlocklist(i)}
               />
             ))}
@@ -964,9 +1080,13 @@ export default function DNS() {
                 url={a.URL}
                 path={a.Path}
                 entries={a.Entries}
+                categories={a.Categories}
                 filterOn={dnsFilterOn}
+                statuses={listStatus.get(`allowlist:${a.Name}`) ?? null}
+                updating={updatingLists.has(`allowlist:${a.Name}`)}
                 busy={busy}
                 onToggle={(on) => toggleAllowlist(i, on)}
+                onUpdateNow={() => void updateList('allowlist', a.Name)}
                 onDelete={() => removeAllowlist(i)}
               />
             ))}
@@ -1717,8 +1837,11 @@ function ListRow({
   categories,
   response,
   filterOn,
+  statuses,
+  updating,
   busy,
   onToggle,
+  onUpdateNow,
   onDelete,
 }: {
   name: string
@@ -1730,8 +1853,14 @@ function ListRow({
   categories?: string[] | null
   response?: BlockResponse
   filterOn: boolean
+  /** What the running engine reports about this list, one record per geo category.
+   *  null/[] ⇒ nothing reported: an older daemon, a stopped engine, or a list that
+   *  has not been applied yet. The row then says so instead of guessing. */
+  statuses: RulesetStatus[] | null
+  updating: boolean
   busy: boolean
   onToggle: (on: boolean) => void
+  onUpdateNow: () => void
   onDelete: () => void
 }) {
   const detail = useMemo<{ text: string; masked: boolean; title?: string }>(() => {
@@ -1755,8 +1884,45 @@ function ListRow({
     }
   }, [source, url, path, entries, categories])
 
-  // A list only actually filters when both it and the master switch are on.
-  const active = enabled && filterOn
+  // url and geosite lists are FETCHED by the engine; inline and file ones are read
+  // straight from the config and are loaded the moment they are applied.
+  const remote = source === 'url' || source === 'geosite'
+  const recs = statuses ?? []
+  const hasStatus = recs.length > 0
+  // A geo list with several categories: the OLDEST fetch (so a category that never
+  // arrived is never hidden behind a fresh sibling) and the SUM of the counts.
+  let ruleCount = 0
+  let neverAny = false
+  let oldestIso = ''
+  for (const s of recs) {
+    ruleCount += s.rule_count
+    if (!s.last_updated) neverAny = true
+    else if (!oldestIso || Date.parse(s.last_updated) < Date.parse(oldestIso)) oldestIso = s.last_updated
+  }
+  const interval = everyLabel(recs[0]?.interval_seconds ?? 0)
+
+  /**
+   * Whether this list is BLOCKING ANYTHING, which is a different question from
+   * whether it is switched on — and the one the row used to answer wrongly.
+   *
+   * "filtering" is now only said when the engine reports rules loaded for it. A
+   * remote list that has never been fetched (the daemon raises this as a critical
+   * apply finding) reads "not loaded", and one that fetched an empty list reads
+   * "empty". Nothing reported at all is "load not reported": unknown, not green.
+   */
+  const state: { text: string; tone: 'on' | 'off' | 'warn' } = !enabled
+    ? { text: 'off', tone: 'off' }
+    : !filterOn
+      ? { text: 'inactive', tone: 'off' }
+      : !remote
+        ? { text: 'filtering', tone: 'on' }
+        : !hasStatus
+          ? { text: 'load not reported', tone: 'off' }
+          : neverAny
+            ? { text: 'not loaded — nothing blocked', tone: 'warn' }
+            : ruleCount === 0
+              ? { text: 'loaded empty — nothing blocked', tone: 'warn' }
+              : { text: 'filtering', tone: 'on' }
 
   return (
     <li className="dns-row">
@@ -1786,10 +1952,39 @@ function ListRow({
               token hidden
             </span>
           )}
-          <span className="dns-row-state" data-active={active ? 'on' : 'off'}>
-            {active ? 'filtering' : 'inactive'}
+          <span className="dns-row-state" data-active={state.tone}>
+            {state.text}
           </span>
         </div>
+        {remote && (
+          <div className="dns-row-sync">
+            <span className="dns-sync-fresh" data-never={hasStatus && neverAny ? 'y' : undefined}>
+              {hasStatus ? relFetch(oldestIso) : 'status pending'}
+            </span>
+            {interval && <span className="dns-sync-every">{interval}</span>}
+            {ruleCount > 0 && (
+              <span className="dns-sync-rules">
+                {ruleCount.toLocaleString('en-US')} rule{ruleCount === 1 ? '' : 's'}
+              </span>
+            )}
+            <button
+              type="button"
+              className="dns-sync-update"
+              onClick={onUpdateNow}
+              disabled={busy || updating}
+              aria-label={`Update ${name} now`}
+            >
+              {updating ? (
+                <>
+                  <span className="dns-sync-spin" aria-hidden="true" />
+                  <span>Updating…</span>
+                </>
+              ) : (
+                'Update now'
+              )}
+            </button>
+          </div>
+        )}
       </div>
       <Button
         className="dns-del"

panel/src/pages/Networks.tsx

@@ -85,6 +85,19 @@ const DEFAULT_TPROXY_PORT = 12345
  * Collapsing those into one switch would make "I want ping to work" silently mean
  * "I permit a parallel VPN bypass", so the middle option exists to remove that
  * false choice — and the labels push anyone who wants diagnostics to `icmp`.
+ *
+ * WHY THIS COPY WAS REWRITTEN. `block` used to say "Nothing leaves except through
+ * the tunnel", and it was not true. The daemon let untunnelable traffic out toward
+ * every destination the ROUTING RULES send direct, on the argument that such a host
+ * already has your address from ordinary TCP. Under the commonest setup here —
+ * "tunnel what's blocked, send the rest direct" — the routing default IS direct, so
+ * that covered everything: `block` behaved exactly like `direct`, including ESP/GRE,
+ * i.e. the parallel-VPN case the middle rung exists to exclude. The daemon now drops
+ * unconditionally under `block`, and this copy states the price instead of hiding it
+ * (the owner's call: this router does not do ping and does not do IPTV).
+ *
+ * `icmp` still carries that destination-dependence for its NON-ping half, so its
+ * cost line says so rather than claiming "nothing else gets out".
  */
 type Untunnelable = 'block' | 'icmp' | 'direct'
 
@@ -98,7 +111,10 @@ function normUntunnelable(raw: string | undefined): Untunnelable {
 
 const UNTUNNELABLE_OPTIONS: ReadonlyArray<{ value: string; label: string }> = [
   { value: 'block', label: 'Block everything — most private' },
-  { value: 'icmp', label: 'Allow ping only — for diagnostics' },
+  // Not "Allow ping only": the rung also lets the other untunnelable protocols
+  // out toward directly-routed addresses, and the cost line below says so. A
+  // label that promised "only" would be contradicted two lines under itself.
+  { value: 'icmp', label: 'Allow ping — for diagnostics' },
   { value: 'direct', label: 'Allow everything — most compatible' },
 ]
 
@@ -110,13 +126,18 @@ interface PolicyCopy {
 
 const UNTUNNELABLE_COPY: Record<Untunnelable, PolicyCopy> = {
   block: {
-    works: 'Nothing leaves except through the tunnel.',
-    cost: 'Ping and traceroute won’t work from your devices, and neither will multicast IPTV or connecting to a VPN from a device on your network.',
+    // Scoped to "this traffic" on purpose. The old line — "Nothing leaves except
+    // through the tunnel" — was doubly loose: it was false (see the note above),
+    // and even read charitably it collides with directly-routed TCP, which does
+    // leave outside the tunnel by design.
+    works:
+      'None of this traffic leaves the router — it’s dropped, whatever your routing rules say. It’s the only setting whose promise doesn’t depend on how the rules are written.',
+    cost: 'Ping and traceroute stop working from your devices. So do IPsec and PPTP VPN connections made from a device on your network, multicast IPTV, and SCTP. VPNs that run over UDP — WireGuard, OpenVPN-UDP, and IPsec through NAT (IKEv2/NAT-T) — are unaffected: they go through the tunnel like everything else.',
     tone: 'good',
   },
   icmp: {
-    works: 'Ping and traceroute work, so you can check whether something is reachable.',
-    cost: 'Whatever you ping sees your real IP address instead of the tunnel’s. Only for hosts you deliberately ping, and nothing else gets out — IPTV and VPN connections stay blocked.',
+    works: 'Ping and traceroute work everywhere, so you can check whether something is reachable.',
+    cost: 'Whatever you ping sees your real IP address instead of the tunnel’s. IPsec, PPTP and IPTV also get out — but only toward addresses your routing rules already send direct, so a VPN app on a device can still open its own connection beside this one if its server is one of those.',
     tone: 'warn',
   },
   direct: {
@@ -551,7 +572,7 @@ export default function Networks({ status }: { status?: Status | null }) {
 
         {untunnelable === 'block' && (
           <p className="nw-sec-note nw-policy-hint">
-            If you just want to check whether a site is reachable, choose <strong>Allow ping only</strong>{' '}
+            If you just want to check whether a site is reachable, choose <strong>Allow ping</strong>{' '}
             rather than allowing everything — it’s the narrower of the two.
           </p>
         )}

panel/src/pages/Nodes.tsx

@@ -741,14 +741,35 @@ export default function Nodes() {
     [config, nodes, save],
   )
 
+  /**
+   * Delete a node, naming everything that still points at it.
+   *
+   * `findNodeReferences` was already here and already right — it just wasn't asked
+   * on the one path where the answer matters. A RENAME carried its references and
+   * said so; a DELETE said "This removes it from the config", which is true of the
+   * node and silent about the rule, group member, chain hop or resolver detour
+   * left spelling a name nothing answers to. That is not a cosmetic dangle: an
+   * unresolved target does not fall through to the default route, so the traffic
+   * aimed at it is blocked.
+   */
   const removeNode = useCallback(
     async (idx: number) => {
       if (!config) return
       const target = nodes[idx]
+      const refs = findNodeReferences(config, target.Name)
+      const shown = refs.slice(0, 4).map((r) => r.label)
+      const more = refs.length - shown.length
       const ok = await confirm({
         label: 'Delete node',
         title: `Delete node “${target.Name}”?`,
-        body: 'This removes it from the config.',
+        body:
+          refs.length === 0
+            ? 'Nothing else in the config points at it.'
+            : `${refSummary(refs)} still ${refs.length === 1 ? 'points' : 'point'} at it — ${shown.join(
+                ', ',
+              )}${
+                more > 0 ? `, and ${more} more` : ''
+              }. Nothing rewrites them, and a target that no longer resolves does not fall through to the default route: the traffic aimed at it is blocked.`,
       })
       if (!ok) return
       const next = nodes.filter((_, i) => i !== idx)

panel/src/pages/Overview.tsx

@@ -4,17 +4,18 @@ import type { LedVariant } from '../components'
 import { fmtDateTime, fmtDuration } from '../format'
 import {
   apply as apiApply,
-  confirm as apiConfirm,
   rollback as apiRollback,
   getConfig,
+  getRulesReachability,
   getStats,
   ApiError,
 } from '../api'
 import type { Model, Stats, Status, StatusWarning } from '../api'
+import { confirmTimeout } from '../pendingConfirm'
 import { navigate } from '../router'
 import type { Route } from '../router'
 import { attentionFindings } from '../findings'
-import { protectionState } from '../planeState'
+import { engineReadout, protectionState } from '../planeState'
 
 // null-safe length for a Go slice that may arrive as null.
 const len = (a: unknown[] | null | undefined): number => (a ? a.length : 0)
@@ -27,7 +28,8 @@ function short(hash: string): string {
   return h.length > 12 ? h.slice(0, 12) : h
 }
 
-type ControlKind = 'apply' | 'confirm' | 'rollback'
+// Confirm is no longer one of them — see the note beside the controls row.
+type ControlKind = 'apply' | 'rollback'
 
 /**
  * Live service uptime in seconds, ticking between status polls.
@@ -42,17 +44,32 @@ type ControlKind = 'apply' | 'confirm' | 'rollback'
  * Returns null when the daemon doesn't report uptime (older builds) — the caller
  * then renders nothing rather than inventing a number.
  */
-function useUptime(status: Status | null): number | null {
+function useUptime(status: Status | null): { seconds: number; startedUnix: number } | null {
   const base = useRef<{ uptime: number; at: number } | null>(null)
+  // The instant the daemon came up, ON THE BROWSER'S CLOCK.
+  //
+  // `status.started_unix` is the router's own clock, and the router has no RTC —
+  // it runs on UTC with no tzdata. Rendering it through the browser's timezone
+  // printed a start time three hours in the FUTURE for a Moscow operator, beside
+  // an uptime of "2 h 41 min". Deriving it instead as now-minus-uptime is a
+  // difference of two client timestamps, so it is skew-proof and can never land
+  // ahead of the clock in the header.
+  const started = useRef<number | null>(null)
   const [, forceTick] = useState(0)
 
   const reported = status?.uptime_seconds
   useEffect(() => {
     if (typeof reported !== 'number' || !Number.isFinite(reported)) {
       base.current = null
+      started.current = null
       return
     }
-    base.current = { uptime: reported, at: Date.now() }
+    const now = Date.now()
+    base.current = { uptime: reported, at: now }
+    // Re-baselining every poll would jitter the displayed second back and forth;
+    // only move it when the estimate has genuinely drifted (a daemon restart).
+    const est = Math.round(now / 1000 - reported)
+    if (started.current === null || Math.abs(started.current - est) > 5) started.current = est
     forceTick((n) => n + 1)
   }, [reported])
 
@@ -64,8 +81,11 @@ function useUptime(status: Status | null): number | null {
     return () => window.clearInterval(id)
   }, [])
 
-  if (!base.current) return null
-  return base.current.uptime + Math.max(0, (Date.now() - base.current.at) / 1000)
+  if (!base.current || started.current === null) return null
+  return {
+    seconds: base.current.uptime + Math.max(0, (Date.now() - base.current.at) / 1000),
+    startedUnix: started.current,
+  }
 }
 
 export function Overview({
@@ -93,6 +113,29 @@ export function Overview({
     void loadConfig()
   }, [loadConfig])
 
+  // ---- how many rules are actually IN FORCE ----------------------------------
+  //
+  // `Rule.Enabled` from /api/config is the DESIRED state; the active WAN profile
+  // overrides it in either direction, and the daemon reports the result as
+  // `effective_enabled`. Counting the saved switches told a router running one
+  // chain that it had "2 / 2" — the Routing page had already been fixed to read
+  // the verdicts, and the home page kept summing the config beside it.
+  //
+  // null ⇒ no verdicts (older daemon, engine stopped, endpoint unreachable). The
+  // module then says so rather than passing the saved count off as the live one.
+  const [inForce, setInForce] = useState<number | null>(null)
+  const loadReach = useCallback(async () => {
+    try {
+      const { rules } = await getRulesReachability()
+      setInForce(rules.filter((r) => r.effective_enabled).length)
+    } catch {
+      setInForce(null)
+    }
+  }, [])
+  useEffect(() => {
+    void loadReach()
+  }, [loadReach])
+
   // ---- live filter stats: poll the aggregate snapshot, degrade to honest empty states ----
   const [stats, setStats] = useState<Stats | null>(null)
   useEffect(() => {
@@ -121,7 +164,7 @@ export function Overview({
     }
   }, [])
 
-  // ---- apply / confirm / rollback ----
+  // ---- apply / rollback ----
   const [busy, setBusy] = useState<ControlKind | null>(null)
   const [result, setResult] = useState<{ ok: boolean; msg: string } | null>(null)
   const [toast, setToast] = useState<string | null>(null)
@@ -139,22 +182,25 @@ export function Overview({
       setBusy(kind)
       setResult(null)
       try {
-        const fn = kind === 'apply' ? apiApply : kind === 'confirm' ? apiConfirm : apiRollback
-        const r = await fn()
+        const r = kind === 'apply' ? await apiApply() : await apiRollback()
         if (r.error) {
           setResult({ ok: false, msg: r.error })
           flash(`${kind} failed`)
         } else {
+          // An apply that changed something armed an auto-rollback, and saying
+          // "data plane reconciled" while a timer runs is how someone walks away
+          // from a config that then reverts. Name the window when there is one.
+          const window = confirmTimeout()
           const msg =
             kind === 'apply'
               ? r.changed
-                ? 'Applied — data plane reconciled'
+                ? window > 0
+                  ? `Applied — keep this config within ${window}s or it rolls back`
+                  : 'Applied — data plane reconciled'
                 : 'Applied — already up to date'
-              : kind === 'confirm'
-                ? 'Confirmed — auto-rollback cancelled'
               : 'Rolled back to last-good config'
           setResult({ ok: true, msg })
-          flash(kind === 'apply' ? 'Applied' : kind === 'confirm' ? 'Confirmed' : 'Rolled back')
+          flash(kind === 'apply' ? 'Applied' : 'Rolled back')
         }
       } catch (e) {
         const msg = e instanceof Error ? e.message : 'request failed'
@@ -163,16 +209,20 @@ export function Overview({
       } finally {
         setBusy(null)
         onStatusChange()
-        if (kind !== 'confirm') void loadConfig()
+        void loadConfig()
+        // An apply or a rollback is exactly what changes which rules are in force.
+        void loadReach()
       }
     },
-    [flash, loadConfig, onStatusChange],
+    [flash, loadConfig, loadReach, onStatusChange],
   )
 
   // ---- service uptime (PROCESS uptime, not "time since the last apply") ----
   const uptime = useUptime(status)
-  const uptimeText = uptime === null ? '' : fmtDuration(uptime)
-  const startedAt = status?.started_unix ? fmtDateTime(status.started_unix) : ''
+  const uptimeText = uptime === null ? '' : fmtDuration(uptime.seconds)
+  // On YOUR clock, derived from the uptime — never `status.started_unix`, which is
+  // the router's clock and has no timezone to convert from. See useUptime.
+  const startedAt = uptime === null ? '' : fmtDateTime(uptime.startedUnix)
 
   // ---- derived display state ----
   const g = config?.Globals
@@ -251,13 +301,12 @@ export function Overview({
       ? `${worstGroup.group} — no answer`
       : `${worstGroup.group} — ${worstGroup.dead} down`
 
-  const engineVariant: LedVariant = !status
-    ? 'off'
-    : status.running && status.active
-      ? 'on'
-      : status.running
-        ? 'amber'
-        : 'crit'
+  // One reading for the engine, and it is able to say "stopped": `status.running`
+  // was a constant `true` on the daemon, so this LED could never go crit and the
+  // Engine module was green through a process that had failed to start. See
+  // planeState.engineState.
+  const engine = engineReadout(status)
+  const engineVariant: LedVariant = engine.variant
 
   const protection = protectionState(status)
   // Configured fail-closed AND actually enforcing it. `none` means nothing is
@@ -334,11 +383,28 @@ export function Overview({
           />
         )}
 
+        {/* "N / M in force", the same reading the Routing page shows — never the
+            count of saved switches. The lamp follows the same rule: a table of
+            rules none of which are in force routes exactly nothing, and it used
+            to sit under a green light saying "0 / 7". */}
         <Module
           name="Routing"
-          value={String(enabledCount(config?.Rules))}
-          unit={`/ ${len(config?.Rules)} rules`}
-          led={{ variant: len(config?.Rules) ? 'on' : 'amber' }}
+          value={inForce === null ? String(enabledCount(config?.Rules)) : String(inForce)}
+          unit={
+            inForce === null
+              ? `/ ${len(config?.Rules)} rules saved`
+              : `/ ${len(config?.Rules)} in force`
+          }
+          led={{
+            variant:
+              len(config?.Rules) === 0
+                ? 'amber'
+                : inForce === null
+                  ? 'off'
+                  : inForce === 0
+                    ? 'amber'
+                    : 'on',
+          }}
           rows={[
             { k: 'egresses', v: String(len(config?.Egresses)) },
             { k: 'default', v: defaultTarget(status, config), hot: true },
@@ -414,6 +480,7 @@ export function Overview({
           unit={status?.version?.includes('-') ? '· ' + status.version.split('-').slice(1).join('-') : ''}
           led={{ variant: engineVariant }}
           rows={[
+            { k: 'process', v: engine.word, hot: engineVariant === 'crit' },
             { k: 'config hash', v: <span className="mono">{short(status?.hash ?? '')}</span> },
             // Uptime of the daemon PROCESS. "started" is the moment it came up,
             // by the router's clock — not the moment a config was applied.
@@ -431,9 +498,14 @@ export function Overview({
           <Button variant="primary" onClick={() => void run('apply')} disabled={busy !== null}>
             {busy === 'apply' ? 'Applying…' : 'Apply config'}
           </Button>
-          <Button onClick={() => void run('confirm')} disabled={busy !== null}>
-            {busy === 'confirm' ? 'Confirming…' : 'Confirm'}
-          </Button>
+          {/* A "Confirm" button used to sit here permanently, and pressing it
+              always printed "Confirmed — auto-rollback cancelled": `apply.Confirm()`
+              returns nil whether or not a window was ever armed, so the message was
+              a success report for an event that usually had not happened.
+              Keeping a config is now offered only while a window is actually open,
+              and that is announced by the app-wide band directly above this page —
+              which is where the button lives, beside the countdown it belongs to,
+              rather than duplicated here. */}
           {canRollback && (
             <Button onClick={() => void run('rollback')} disabled={busy !== null}>
               {busy === 'rollback' ? 'Rolling back…' : 'Rollback'}

panel/src/pages/Routing.tsx

@@ -12,6 +12,7 @@ import {
   ApiError,
 } from '../api'
 import type { Model, Rule, RuleReach, Ruleset, RulesetStatus } from '../api'
+import { everyLabel, relFetch } from '../format'
 
 // ---------------------------------------------------------------------------
 // The api.ts `Rule` is a deliberately thin subset (Name/Enabled/Order/Target/
@@ -203,35 +204,8 @@ function errMsg(e: unknown): string {
 // --- remote-list freshness (feedback #9) ------------------------------------
 // A url-source ruleset re-fetches on a cadence; the engine reports when it last
 // pulled and how many rules the list holds. Match a ruleset to its status by the
-// engine tag `rs-<name>`.
-
-/** "updated 3h ago" / "never updated" for a remote list's last fetch. */
-function relFetch(iso: string): string {
-  if (!iso) return 'never updated'
-  const t = Date.parse(iso)
-  if (Number.isNaN(t)) return 'never updated'
-  const s = Math.max(0, Math.floor((Date.now() - t) / 1000))
-  if (s < 45) return 'updated just now'
-  const m = Math.floor(s / 60)
-  if (m < 60) return `updated ${m}m ago`
-  const h = Math.floor(m / 60)
-  if (h < 24) return `updated ${h}h ago`
-  const d = Math.floor(h / 24)
-  return `updated ${d}d ago`
-}
-
-/** "every 24h" for an auto-update cadence in seconds ("" when there is none). */
-function everyLabel(sec: number): string {
-  if (!sec || sec <= 0) return ''
-  if (sec % 3600 === 0) {
-    const h = sec / 3600
-    if (h < 48) return `every ${h}h`
-    if (sec % 86400 === 0) return `every ${sec / 86400}d`
-    return `every ${h}h`
-  }
-  if (sec % 60 === 0) return `every ${sec / 60}m`
-  return `every ${sec}s`
-}
+// engine tag `rs-<name>`. The two readings (relFetch / everyLabel) live in
+// format.ts because the DNS page shows the same ones for blocklists.
 
 /** A rule with no matcher of any kind is the effective catch-all (route Final).
  *  Mirrors model.IsCatchAll on the daemon side — the two must agree or the
@@ -286,6 +260,57 @@ function formHasNoMatchers(f: {
   )
 }
 
+/**
+ * What happens to the network when the default route stops being emitted —
+ * whether it is deleted or merely switched off (the engine emits neither).
+ *
+ * The old text was one sentence for every rule: "Traffic it matched will fall
+ * through to the next rule." For an ordinary rule that is true. For the catch-all
+ * there IS no next rule, and what happens instead is decided by the kill-switch:
+ * generate/route.go sets `final := tagBlock` and only `kill_switch=open` swaps
+ * that for `direct`. So removing the default either takes the whole network
+ * offline or puts the whole network on the naked WAN — and the page said "falls
+ * through to the next rule" for both, on a row it had already badged
+ * "DEFAULT ROUTE · FINAL".
+ *
+ * `successor` is the rule that would inherit route.Final instead (a config can
+ * carry more than one conditionless rule; the last one wins). When there is one,
+ * nothing is lost — the honest warning is that the destination changes.
+ */
+function defaultRouteConsequence(
+  killSwitch: string,
+  successor: { name: string; order: number; target: string } | null,
+): ReactNode {
+  if (successor) {
+    return (
+      <>
+        This is the router’s <strong>default route</strong> — everything no other rule matches
+        follows it. Remove it and “{successor.name}” (order {successor.order}) has no conditions
+        either, so it takes over: unmatched traffic goes to{' '}
+        <strong className="mono">{successor.target}</strong> instead.
+      </>
+    )
+  }
+  if (killSwitch === 'open') {
+    return (
+      <>
+        This is the router’s <strong>default route</strong> — everything no other rule matches
+        follows it, and no other rule matches everything. With the kill-switch set to{' '}
+        <strong>fail-open</strong>, unmatched traffic then leaves through your normal internet
+        connection with your real address — unproxied and unfiltered.
+      </>
+    )
+  }
+  return (
+    <>
+      This is the router’s <strong>default route</strong> — everything no other rule matches
+      follows it, and no other rule matches everything. With the kill-switch set to{' '}
+      <strong>fail-closed</strong>, unmatched traffic is then <strong>blocked</strong>: devices on
+      your network lose the internet until you add a default back.
+    </>
+  )
+}
+
 /** Effective routing target for a rule (Target wins; a bare Egress is a target too). */
 function effectiveTarget(r: RRule): string {
   if (r.Target && r.Target.trim()) return r.Target.trim()
@@ -678,17 +703,61 @@ export default function Routing() {
     [config, rules, rulesets, rulesetUsage, persist, confirm],
   )
 
+  /**
+   * Is this rule the one the ENGINE uses as route.Final right now, and in force?
+   *
+   * Both halves matter. A conditionless rule the daemon reports as shadowed owns
+   * nothing (the row already says "never applies"), and one that is switched off
+   * is not being emitted either — removing either changes no traffic, so neither
+   * earns a warning.
+   */
+  const isLiveDefault = useCallback(
+    (r: RRule): boolean => isCatchAll(r) && shadowOf(r) === null && forceOf(r).on,
+    [shadowOf, forceOf],
+  )
+
+  /** Which rule would inherit route.Final if `name` stopped being emitted: the
+   *  LAST remaining conditionless, switched-on rule. null when there is none. */
+  const successorDefault = useCallback(
+    (name: string): { name: string; order: number; target: string } | null => {
+      for (let i = rules.length - 1; i >= 0; i--) {
+        const r = rules[i]
+        if (r.Name === name) continue
+        if (r.Enabled && isCatchAll(r)) {
+          return { name: r.Name, order: r.Order, target: effectiveTarget(r) }
+        }
+      }
+      return null
+    },
+    [rules],
+  )
+
+  const killSwitch = (config?.Globals?.KillSwitch ?? 'closed') === 'open' ? 'open' : 'closed'
+
   const onToggle = useCallback(
-    (name: string) => {
+    async (name: string) => {
       const target = rules.find((r) => r.Name === name)
       if (!target) return
       const nextState = !target.Enabled
+      // Switching the default route OFF is the same event as deleting it — the
+      // generator emits only enabled rules — so it asks the same question. It used
+      // to ask nothing at all, which made the least reversible control on the page
+      // the only one with no confirmation.
+      if (!nextState && isLiveDefault(target)) {
+        const ok = await confirm({
+          label: 'Turn off default route',
+          title: `Turn off the default route “${name}”?`,
+          body: defaultRouteConsequence(killSwitch, successorDefault(name)),
+          confirmLabel: 'Turn it off',
+        })
+        if (!ok) return
+      }
       commitRules(
         rules.map((r) => (r.Name === name ? { ...r, Enabled: nextState } : r)),
         `${name} ${nextState ? 'enabled' : 'disabled'}`,
       )
     },
-    [rules, commitRules],
+    [rules, commitRules, confirm, isLiveDefault, killSwitch, successorDefault],
   )
 
   const onMove = useCallback(
@@ -716,10 +785,17 @@ export default function Routing() {
 
   const onDelete = useCallback(
     async (name: string) => {
+      const target = rules.find((r) => r.Name === name)
+      if (!target) return
+      // The catch-all has no "next rule" to fall through to — see
+      // defaultRouteConsequence. Every other rule keeps the plain sentence.
+      const isDefault = isLiveDefault(target)
       const ok = await confirm({
-        label: 'Delete rule',
-        title: `Delete rule "${name}"?`,
-        body: 'Traffic it matched will fall through to the next rule.',
+        label: isDefault ? 'Delete default route' : 'Delete rule',
+        title: isDefault ? `Delete the default route “${name}”?` : `Delete rule “${name}”?`,
+        body: isDefault
+          ? defaultRouteConsequence(killSwitch, successorDefault(name))
+          : 'Traffic it matched will fall through to the next rule.',
       })
       if (!ok) return
       commitRules(
@@ -727,7 +803,7 @@ export default function Routing() {
         `${name} deleted`,
       )
     },
-    [rules, commitRules, confirm],
+    [rules, commitRules, confirm, isLiveDefault, killSwitch, successorDefault],
   )
 
   // Insert a new rule just above the catch-all (so a specific rule can actually match).

panel/src/pages/Settings.tsx

@@ -1,7 +1,7 @@
 import './Settings.css'
 import { useCallback, useEffect, useRef, useState } from 'react'
 import type { ReactNode } from 'react'
-import { Button, Led, Select, Toggle } from '../components'
+import { Button, Led, Select, Toggle, useConfirm } from '../components'
 import { apply as apiApply, downloadLog, getConfig, putConfig, ApiError } from '../api'
 import type { Globals, LogRange, Model } from '../api'
 
@@ -125,6 +125,7 @@ const STATS_BACKENDS: ReadonlyArray<{ value: string; label: string }> = [
 // ---- page ------------------------------------------------------------------
 
 export default function Settings() {
+  const confirm = useConfirm()
   const [config, setConfig] = useState<Model | null>(null)
   const [loadError, setLoadError] = useState<string | null>(null)
 
@@ -257,6 +258,48 @@ export default function Settings() {
   const groupHealthOn = globals?.GroupHealth !== false
 
   const killSwitch = globals?.KillSwitch === 'open' ? 'open' : 'closed'
+
+  /**
+   * The master switch, which is the most destructive control in the panel and was
+   * the only one that asked nothing.
+   *
+   * Turning it off is not "pausing the proxy": apply.go runs Teardown() — the nft
+   * table goes, the policy routing goes, `plane` becomes `none`. The kill-switch
+   * does not save you, because a kill-switch is a rule in a table that no longer
+   * exists. Everything on the LAN then leaves through the plain WAN, unproxied and
+   * unfiltered. Deleting a rule-set asked for confirmation; this did not.
+   *
+   * Turning it back ON is not destructive and is not gated.
+   */
+  const toggleService = useCallback(
+    async (on: boolean) => {
+      if (!on) {
+        const ok = await confirm({
+          label: 'Turn off the service',
+          title: 'Turn the proxy engine off?',
+          body: (
+            <>
+              This tears the whole data plane down — the firewall table, the policy routing and the
+              DNS interception are removed, not paused. Nothing is proxied, filtered or blocked, and
+              every device leaves through your normal internet connection with its real address.{' '}
+              {killSwitch === 'closed' ? (
+                <>
+                  The kill-switch does not hold here: with nothing installed there is nothing left
+                  to block with.
+                </>
+              ) : (
+                <>The kill-switch is already open, so nothing changes about that.</>
+              )}
+            </>
+          ),
+          confirmLabel: 'Turn it off',
+        })
+        if (!ok) return
+      }
+      setGlobal('Enabled', on, on ? 'Engine enabled' : 'Engine disabled')
+    },
+    [confirm, killSwitch, setGlobal],
+  )
   const killNote =
     killSwitch === 'open'
       ? 'Fail-open — if the engine stops, traffic falls back to the direct WAN. Stays online, but unprotected.'
@@ -296,10 +339,13 @@ export default function Settings() {
         <div className="set-groups">
           {/* ---- SERVICE ---- */}
           <Group title="Service" count={globals?.Enabled ? 'enabled' : 'disabled'}>
-            <Field label="Proxy engine" note="Master on/off for the whole appliance.">
+            <Field
+              label="Proxy engine"
+              note="Master on/off for the whole appliance. Off removes the firewall table and the policy routing — every device goes out directly, with no kill-switch to catch it."
+            >
               <Toggle
                 pressed={globals?.Enabled ?? false}
-                onChange={(on) => setGlobal('Enabled', on, on ? 'Engine enabled' : 'Engine disabled')}
+                onChange={(on) => void toggleService(on)}
                 label={globals?.Enabled ? 'Disable proxy engine' : 'Enable proxy engine'}
                 size="md"
                 disabled={busy || !ready}

panel/src/pages/Targets.css

@@ -1054,8 +1054,11 @@
  * that before a word has been read.
  *
  * The two marks carry two different facts and must not be conflated:
- *   - the LAMP is that hop's own measurement (good / warn / crit / unlit), and a
- *     hop below the break that answered keeps its green, because it did answer;
+ *   - the LAMP is that hop's own measurement (good / warn / crit / unlit). Below
+ *     the break there is no measurement to draw: the daemon stops walking at the
+ *     first dead hop, so those lamps are UNLIT and the row says which hop stopped
+ *     the walk. Unlit is never a shade of red — it claims nothing, which is the
+ *     truth about a hop nobody dialled;
  *   - the CONDUCTOR is reachability through the path, which really does stop.
  *
  * Orange is untouched here. Semantics carry every colour, and everything that is
@@ -1199,6 +1202,12 @@
   font-size: 12px;
   color: var(--faint);
 }
+/* A blocked hop's phrase carries a tooltip with the blocking hop's engine
+   outbound, so it takes the same help cursor as .ch-dead. No colour of its own:
+   the finding is red once, on the hop that actually failed. */
+.ch-blocked {
+  cursor: help;
+}
 .ch-age {
   margin-left: auto;
   font-size: 10.5px;
@@ -1251,6 +1260,11 @@
   font-size: 10.5px;
   color: var(--faint);
 }
+/* On a blocked hop this chip says "set to", not "now": a pick nothing crossed.
+   It steps back to faint so it can't be mistaken for a live reading. */
+.ch-hop--blocked .ch-now {
+  color: var(--faint);
+}
 .ch-now {
   max-width: 28ch;
   overflow: hidden;

panel/src/pages/Targets.tsx

@@ -2242,12 +2242,22 @@ function ChainRow({
   onDelete: () => void
 }) {
   const hops = asArray(chain.Hops)
+  // A LEADING `egress:` is not a hop and the rail below already knows it: the
+  // daemon lifts it into hop 1's entry detour (see hopLabels), so it is tagged
+  // "entry" and never numbered. The badge counted it anyway, which is how a chain
+  // drawn with four hops came to be labelled "5 hops" directly above them.
+  const entryEgress = hops.length > 0 && hops[0].startsWith('egress:')
+  const numbered = entryEgress ? hops.length - 1 : hops.length
   return (
     <li className="tg-row">
       <div className="tg-row-main">
         <div className="tg-row-l1">
           <span className="tg-row-name">{chain.Name}</span>
-          <span className="tg-badge">{hops.length} hop{hops.length === 1 ? '' : 's'}</span>
+          <span className="tg-badge">
+            {numbered === 0 && entryEgress
+              ? 'entry only · no exit'
+              : `${numbered} hop${numbered === 1 ? '' : 's'}`}
+          </span>
         </div>
         <div className="tg-row-l2">
           {hops.length === 0 ? (
@@ -2337,6 +2347,8 @@ function hopLabels(defs: string[], hops: ChainHopHealth[]): (string | undefined)
  *
  * `dead` is crit and `untested` is an UNLIT socket — never red, because nothing
  * has been measured and an unlit lamp is this panel's way of saying "no verdict".
+ * That covers a hop the walk never reached (`blocked_by`) too: it is neither
+ * healthy nor broken, and unlit is the only mark that claims neither.
  * The fourth case is the page's existing house reading, applied here for
  * consistency rather than invented: a group hop that is carrying traffic but has
  * confirmed failures on its board is amber. `state` stays the daemon's word for
@@ -2360,12 +2372,20 @@ function hopLed(h: ChainHopHealth): LedVariant {
  * conductor answers the second one before you have read a single word, which is
  * the whole reason this feature exists.
  *
- * It stays honest by keeping the two facts on two different marks. Each LAMP is
- * that hop's own measurement and never changes because of a hop in front of it —
- * a hop after the break that answers still shows green, because it really did
- * answer. The CONDUCTOR is reachability through the path, and that genuinely does
- * stop at the break. Nothing here is re-derived from the daemon's counters; the
- * only thing the panel adds is what a chain structurally is.
+ * It stays honest by keeping two different facts on two different marks. The
+ * CONDUCTOR is reachability through the path, and that genuinely does stop at the
+ * break. The LAMPS are measurements — and there are none below the break to show:
+ * the daemon walks the path in order and stops at the first hop that does not
+ * answer, because every later hop is dialled THROUGH that one. Those hops arrive
+ * `untested` with `blocked_by` naming the hop that stopped the walk, so their
+ * lamps stay UNLIT: not a soft red, not a pale green, just this panel's way of
+ * saying no verdict exists about a hop nobody reached. The row says so in words
+ * too, naming that hop, because "why is this row empty" is the question the shape
+ * alone cannot answer.
+ *
+ * Nothing here is re-derived from the daemon's counters — the block, the zeroed
+ * numbers and the state all come off the wire. The only thing the panel adds is
+ * what a chain structurally is.
  *
  * Everything around the rail is deliberately quiet: no colour but the semantic
  * lamps, no motion at all, the orange accent untouched.
@@ -2412,9 +2432,14 @@ function ChainHopRail({
         {ordered.map((h, i) => {
           const label = labels[i]
           const severed = breakAt >= 0 && i > breakAt
+          // Straight off the wire: present ⇒ the walk never reached this hop, so
+          // there is nothing measured here and the daemon has already named the
+          // hop that stopped it. Never inferred from the counters.
+          const blocked = h.blocked_by
           const cls = [
             'ch-hop',
             `ch-hop--${h.state}`,
+            blocked ? 'ch-hop--blocked' : '',
             severed ? 'ch-hop--severed' : '',
             h.exit ? 'ch-hop--exit' : '',
             i === 0 ? 'ch-hop--first' : '',
@@ -2439,7 +2464,20 @@ function ChainHopRail({
                   {h.state === 'alive' && h.delay_ms > 0 && (
                     <span className="ch-delay mono">{h.delay_ms} ms</span>
                   )}
-                  {h.state === 'untested' && <span className="ch-quiet">not measured yet</span>}
+                  {/* Two different silences. A plain untested hop is a timing
+                      gap that fills in by itself; a BLOCKED one never will,
+                      because the walk stopped above it — so it says which hop
+                      stopped it instead of implying someone should wait. */}
+                  {blocked ? (
+                    <span
+                      className="ch-quiet ch-blocked"
+                      title={`hop ${blocked.index} did not answer, so nothing was dialled through it (engine outbound ${blocked.tag})`}
+                    >
+                      no reading — the probe stopped at hop {blocked.index}
+                    </span>
+                  ) : (
+                    h.state === 'untested' && <span className="ch-quiet">not measured yet</span>
+                  )}
                   {age && <span className="ch-age mono">{age}</span>}
                 </div>
 
@@ -2447,12 +2485,16 @@ function ChainHopRail({
                     only restate the lamp. A group hop rolls up its per-hop member
                     copies, and those read exactly as they do everywhere else in
                     this app: alive out of TESTED, with the untested remainder as a
-                    quiet aside only when there is one. */}
+                    quiet aside only when there is one. A blocked hop has those
+                    counters zeroed by the daemon, so it lands in the tested === 0
+                    branch — and there it must say the members were never REACHED,
+                    not that they are still waiting their turn. */}
                 {h.kind === 'group' && h.total > 0 && (
                   <div className="ch-l2">
                     {h.tested === 0 ? (
                       <span className="ch-rest mono">
-                        {h.total} member{h.total === 1 ? '' : 's'}, none measured
+                        {h.total} member{h.total === 1 ? '' : 's'},{' '}
+                        {blocked ? 'none of them reached' : 'none measured'}
                       </span>
                     ) : (
                       <>
@@ -2475,12 +2517,19 @@ function ChainHopRail({
                         )}
                       </>
                     )}
+                    {/* The wrapper keeps its pick even when nothing crossed it,
+                        so on a blocked hop this is the node it WOULD use — say
+                        that, rather than "now", which claims live traffic. */}
                     {h.selected && (
                       <span
                         className="ch-now mono"
-                        title={`Traffic crossing hop ${h.index} of “${chain}” is on ${h.selected}`}
+                        title={
+                          blocked
+                            ? `Hop ${h.index} of “${chain}” is set to ${h.selected}; nothing crossed it to measure`
+                            : `Traffic crossing hop ${h.index} of “${chain}” is on ${h.selected}`
+                        }
                       >
-                        now → {h.selected}
+                        {blocked ? 'set to' : 'now'} → {h.selected}
                       </span>
                     )}
                   </div>
@@ -2493,14 +2542,15 @@ function ChainHopRail({
 
       {/* The sentence the rail's shape implies, written out — because the break is
           the answer someone came here for, and a graphic alone should never be the
-          only place a finding exists. */}
+          only place a finding exists. It names the dead hop, since that is the one
+          thing here anybody can act on. */}
       {breakAt >= 0 && (
         <p className="gh-say gh-say--bad">
           Hop {ordered[breakAt].index}
-          {labels[breakAt] ? ` (${labels[breakAt]})` : ''} was probed and did not answer. A chain is
-          one path, so traffic stops there
+          {labels[breakAt] ? ` (${labels[breakAt]})` : ''} was probed and did not answer, so traffic
+          stops there
           {breakAt < ordered.length - 1
-            ? ' — the hops after it answer on their own, but nothing reaches them through this chain.'
+            ? ' — and the hops below it are dialled through it, so nothing reached them and nothing is known about them.'
             : '.'}
         </p>
       )}

panel/src/pendingConfirm.test.ts

@@ -0,0 +1,91 @@
+// pendingConfirm — the record of an armed auto-rollback, shared by the whole panel.
+//
+// Run with `npm test`. The module imports React only for its hook; the plain
+// functions exercised here touch neither React nor the DOM, and `localStorage` is
+// absent under node, which is itself one of the cases worth pinning (the panel
+// must still work, it just forgets on reload).
+//
+// What these protect:
+//   - arming when commit-confirm is OFF must record nothing. The daemon does not
+//     arm a window then, and a countdown for a rollback that will never happen is
+//     the same class of lie as the "Confirmed" message this module replaced.
+//   - a window that has elapsed reads as gone, so nothing renders "0 s left".
+//   - expiry notifies exactly once even though several components watch it.
+
+import { test } from 'node:test'
+import assert from 'node:assert/strict'
+
+import {
+  armPendingConfirm,
+  clearPendingConfirm,
+  confirmTimeout,
+  noteConfirmTimeout,
+  onPendingConfirmExpire,
+  readPendingConfirm,
+} from './pendingConfirm.ts'
+
+test('commit-confirm off ⇒ arming records nothing', () => {
+  noteConfirmTimeout(0)
+  assert.equal(confirmTimeout(), 0)
+  armPendingConfirm()
+  assert.equal(readPendingConfirm(), null)
+})
+
+test('a window is recorded with the timeout the config reported', () => {
+  noteConfirmTimeout(90)
+  armPendingConfirm()
+  const p = readPendingConfirm()
+  assert.notEqual(p, null)
+  assert.equal(p!.total, 90)
+  // Deadline is in the future and within a second of now + the window.
+  const left = (p!.until - Date.now()) / 1000
+  assert.ok(left > 89 && left <= 90, `expected ~90s left, got ${left}`)
+  clearPendingConfirm()
+  assert.equal(readPendingConfirm(), null)
+})
+
+test('switching commit-confirm off drops a window that was already armed', () => {
+  noteConfirmTimeout(60)
+  armPendingConfirm()
+  assert.notEqual(readPendingConfirm(), null)
+  noteConfirmTimeout(0)
+  assert.equal(readPendingConfirm(), null)
+})
+
+test('an elapsed window reads as gone, never as a countdown at zero', () => {
+  noteConfirmTimeout(1)
+  armPendingConfirm()
+  const p = readPendingConfirm()
+  assert.notEqual(p, null)
+  // Wind the clock forward rather than sleeping through the window.
+  const realNow = Date.now
+  Date.now = () => realNow() + 5000
+  try {
+    assert.equal(readPendingConfirm(), null)
+  } finally {
+    Date.now = realNow
+  }
+  clearPendingConfirm()
+})
+
+test('confirming does NOT fire the expiry listeners', () => {
+  noteConfirmTimeout(30)
+  let fired = 0
+  const off = onPendingConfirmExpire(() => {
+    fired++
+  })
+  armPendingConfirm()
+  clearPendingConfirm()
+  off()
+  assert.equal(fired, 0)
+})
+
+test('a nonsense timeout is ignored rather than taken as "off"', () => {
+  noteConfirmTimeout(45)
+  noteConfirmTimeout(Number.NaN)
+  noteConfirmTimeout(-1)
+  noteConfirmTimeout(undefined)
+  assert.equal(confirmTimeout(), 45)
+  clearPendingConfirm()
+  noteConfirmTimeout(0)
+})

panel/src/pendingConfirm.ts

@@ -0,0 +1,186 @@
+// The commit-confirm window, as ONE fact the whole panel can see.
+//
+// WHY THIS EXISTS. `POST /api/apply` always arms an auto-rollback for
+// `Globals.ConfirmTimeout` seconds (shater/panel/api.go handleApply →
+// ArmRollback) — EVERY Apply button does that, not just the one on the Apply
+// page. But the countdown, and the button that stops it, lived in one component's
+// local state. So:
+//
+//   - pressing Apply on Routing/DNS/Nodes/Settings/Devices/Profiles/Targets said
+//     "Applied" and nothing else; the operator walked away and the router quietly
+//     reverted a minute later;
+//   - reloading the tab wiped the countdown AND the "Keep this config" button, so
+//     there was no way left to confirm from the panel at all.
+//
+// The daemon does not report a deadline, so this module records the one the panel
+// itself armed, in `localStorage`. That is a deliberately modest claim — it knows
+// about windows THIS BROWSER opened and says nothing about one opened elsewhere —
+// but it survives a reload, a new tab and a navigation, which is what the two
+// failures above needed.
+//
+// It is also the answer to "is there anything to confirm?". `apply.Confirm()`
+// returns nil unconditionally, so a Confirm button that is always live can only
+// ever report success. Gating it on a record here means the panel offers the
+// action when it knows a window is open, and then reports an outcome it knows.
+
+import { useEffect, useState } from 'react'
+
+/** A live commit-confirm window the panel armed. */
+export interface PendingConfirm {
+  /** Epoch ms at which the daemon auto-rolls back if nobody confirms. */
+  until: number
+  /** The window it started with, in seconds — the progress bar's denominator. */
+  total: number
+}
+
+const KEY = 'shater.pendingConfirm'
+
+type Listener = () => void
+const listeners = new Set<Listener>()
+const expiryListeners = new Set<Listener>()
+
+/** localStorage is absent under SSR/tests and throws in some privacy modes. A
+ *  panel that cannot remember a window must still work — it just forgets on
+ *  reload, which is exactly the old behaviour and no worse. */
+function store(): Storage | null {
+  try {
+    return typeof localStorage === 'undefined' ? null : localStorage
+  } catch {
+    return null
+  }
+}
+
+function load(): PendingConfirm | null {
+  const s = store()
+  if (!s) return null
+  try {
+    const raw = s.getItem(KEY)
+    if (!raw) return null
+    const v = JSON.parse(raw) as Partial<PendingConfirm>
+    if (typeof v.until !== 'number' || typeof v.total !== 'number') return null
+    if (!Number.isFinite(v.until)) return null
+    return { until: v.until, total: v.total }
+  } catch {
+    return null
+  }
+}
+
+// The single in-process copy. Storage is the durable mirror, not the source of
+// truth for a running tab: a `storage` event re-hydrates it when another tab
+// writes.
+let armed: PendingConfirm | null = load()
+
+function emit() {
+  for (const l of [...listeners]) l()
+}
+
+function write(v: PendingConfirm | null) {
+  armed = v
+  const s = store()
+  if (s) {
+    try {
+      if (v) s.setItem(KEY, JSON.stringify(v))
+      else s.removeItem(KEY)
+    } catch {
+      // Storage full or blocked — the in-process copy still drives this tab.
+    }
+  }
+  emit()
+}
+
+/** The armed window, or null when there is none or it has already elapsed. */
+export function readPendingConfirm(): PendingConfirm | null {
+  if (!armed) return null
+  return armed.until > Date.now() ? armed : null
+}
+
+// ---- the window's length ----------------------------------------------------
+
+// `Globals.ConfirmTimeout` is all that is needed to arm a window, and every page
+// reads the config anyway — so api.getConfig() feeds it here rather than each
+// caller threading it through. 0 (or never seen) means commit-confirm is off, and
+// arming then does nothing: an apply on such a router really is immediate.
+let timeout = 0
+
+export function noteConfirmTimeout(seconds: number | undefined) {
+  if (typeof seconds !== 'number' || !Number.isFinite(seconds) || seconds < 0) return
+  timeout = Math.floor(seconds)
+  // A window armed before commit-confirm was switched off is no longer real —
+  // drop it rather than count down to an event that will not happen.
+  if (timeout === 0 && armed) write(null)
+}
+
+export function confirmTimeout(): number {
+  return timeout
+}
+
+/** Record the window an apply just opened. Call only when the apply CHANGED
+ *  something: an unchanged apply reconciles nothing and arms nothing. */
+export function armPendingConfirm() {
+  if (timeout <= 0) return
+  write({ until: Date.now() + timeout * 1000, total: timeout })
+}
+
+/** Confirm and rollback both end the window. */
+export function clearPendingConfirm() {
+  if (armed) write(null)
+}
+
+/** Fires when a window ran out on its own — i.e. the daemon has reverted — and
+ *  NOT when it was confirmed or rolled back. Returns an unsubscribe. */
+export function onPendingConfirmExpire(fn: Listener): () => void {
+  expiryListeners.add(fn)
+  return () => {
+    expiryListeners.delete(fn)
+  }
+}
+
+/** Idempotent: several mounted countdowns race to notice the same deadline, and
+ *  only the first one gets to announce it. */
+function expire() {
+  if (!armed) return
+  write(null)
+  for (const l of [...expiryListeners]) l()
+}
+
+// Another tab confirming, rolling back or applying is the same event as this one
+// doing it.
+if (typeof window !== 'undefined') {
+  window.addEventListener('storage', (e) => {
+    if (e.key !== KEY && e.key !== null) return
+    armed = load()
+    emit()
+  })
+}
+
+/**
+ * The armed window and its remaining seconds, ticking once a second.
+ *
+ * Returns null when nothing is armed. While non-null `remaining` is at least 1:
+ * reaching zero clears the record and notifies {@link onPendingConfirmExpire}, so
+ * no component ever renders "0 s left" for a window that is already over.
+ */
+export function usePendingConfirm(): { pending: PendingConfirm; remaining: number } | null {
+  const [, tick] = useState(0)
+
+  useEffect(() => {
+    const sync = () => tick((n) => n + 1)
+    listeners.add(sync)
+    sync()
+    return () => {
+      listeners.delete(sync)
+    }
+  }, [])
+
+  useEffect(() => {
+    const id = window.setInterval(() => {
+      if (armed && armed.until <= Date.now()) expire()
+      else if (armed) tick((n) => n + 1)
+    }, 1000)
+    return () => window.clearInterval(id)
+  }, [])
+
+  const pending = readPendingConfirm()
+  if (!pending) return null
+  return { pending, remaining: Math.max(1, Math.ceil((pending.until - Date.now()) / 1000)) }
+}

panel/src/planeState.test.ts

@@ -15,7 +15,7 @@
 import { test } from 'node:test'
 import assert from 'node:assert/strict'
 
-import { protectionState } from './planeState.ts'
+import { engineReadout, engineState, protectionState } from './planeState.ts'
 import type { Status, Traffic } from './api.ts'
 
 /** A healthy, fully-installed router; `traffic` is what each case varies. */
@@ -148,3 +148,44 @@ test('daemon too old to send `plane` keeps its own fallback', () => {
     'Starting up',
   )
 })
+
+// --- engineState: the reading that could not say "down" ----------------------
+//
+// `apply.Status.running` was a hardcoded `true` on the daemon, so every panel LED
+// derived from it was lit before it was read: App's master indicator could not
+// reach its "Offline" branch, and Apply's "engine: running / stopped" row had one
+// reachable value. These pin the three answers, and that "up" needs agreement.
+
+test('engine_running:false is down even while the daemon claims it is running', () => {
+  assert.equal(engineState(status({ running: true, engine_running: false })), 'down')
+  assert.equal(engineReadout(status({ running: true, engine_running: false })).variant, 'crit')
+  assert.equal(engineReadout(status({ running: true, engine_running: false })).word, 'stopped')
+})
+
+test('a daemon that reports itself stopped is down whatever engine_running says', () => {
+  assert.equal(engineState(status({ running: false, engine_running: true })), 'down')
+})
+
+test('up needs both, and then active/idle splits the lamp', () => {
+  assert.equal(engineState(status({ running: true, engine_running: true })), 'up')
+  assert.equal(engineReadout(status({ active: true })).variant, 'on')
+  assert.equal(engineReadout(status({ active: true })).word, 'active')
+  assert.equal(engineReadout(status({ active: false })).variant, 'amber')
+  assert.equal(engineReadout(status({ active: false })).word, 'idle')
+})
+
+test('an older daemon with no engine_running is unknown — an unlit lamp, never green', () => {
+  const { engine_running, ...old } = status()
+  void engine_running
+  assert.equal(engineState(old as Status), 'unknown')
+  const r = engineReadout(old as Status)
+  assert.equal(r.variant, 'off')
+  assert.notEqual(r.variant, 'on')
+  assert.equal(r.word, 'not reported')
+})
+
+test('no status at all is unknown, not down', () => {
+  assert.equal(engineState(null), 'unknown')
+  assert.equal(engineReadout(null).variant, 'off')
+  assert.equal(engineReadout(null).word, 'checking…')
+})

panel/src/planeState.ts

@@ -21,6 +21,56 @@ export interface ProtectionState {
   alarm: boolean
 }
 
+// ---------------------------------------------------------------------------
+// Is the engine actually up?
+// ---------------------------------------------------------------------------
+
+/**
+ * Three answers, and "unknown" is one of them.
+ *
+ *   up      — the sing-box process is running.
+ *   down    — it is not. Nothing is being proxied or filtered.
+ *   unknown — nobody has told us. Never paint this green.
+ *
+ * THIS EXISTS BECAUSE `status.running` COULD NOT SAY "down". It is the DAEMON's
+ * own liveness, and on the daemons this panel shipped against it was a hardcoded
+ * `true` (apply.go) — so `running ? 'running' : 'stopped'` had exactly one
+ * reachable branch, and every LED derived from it was lit before it was read. A
+ * router whose engine failed to start, with a fail-closed holding plan installed
+ * and no internet on the LAN, showed three green lamps on the page people go to
+ * when they are trying to fix it.
+ *
+ * `engine_running` is the field that answers the question honestly, so it decides
+ * `up`. Either field may still prove a NEGATIVE — a daemon that reports itself
+ * stopped cannot be running an engine — and a negative always wins, so "up" needs
+ * both to agree. Neither field asserting anything leaves `unknown`.
+ */
+export type EngineState = 'up' | 'down' | 'unknown'
+
+export function engineState(status: Status | null): EngineState {
+  if (!status) return 'unknown'
+  if (!status.running) return 'down'
+  if (typeof status.engine_running === 'boolean') return status.engine_running ? 'up' : 'down'
+  return 'unknown'
+}
+
+/** How the engine's lamp is painted and what the readout beside it says.
+ *
+ *  `unknown` is an UNLIT socket, never amber and never green: amber is this
+ *  panel's "degraded", and there is nothing to be degraded about when no reading
+ *  has arrived. `down` is crit even when the kill-switch caught it — the engine
+ *  being dead is the fault; whether traffic leaks is a separate lamp. */
+export function engineReadout(status: Status | null): { variant: LedVariant; word: string } {
+  switch (engineState(status)) {
+    case 'down':
+      return { variant: 'crit', word: 'stopped' }
+    case 'up':
+      return status?.active ? { variant: 'on', word: 'active' } : { variant: 'amber', word: 'idle' }
+    default:
+      return { variant: 'off', word: status ? 'not reported' : 'checking…' }
+  }
+}
+
 /**
  * `plane` + `engine_running` express the state more precisely than the three
  * booleans the old status strip exposed (engine active / config enabled / nft
@@ -101,8 +151,18 @@ export function protectionState(status: Status | null): ProtectionState {
           }
   }
 
-  // Older daemon with no `plane` field: fall back to what we can observe.
-  if (status.running && status.active && status.table) {
+  // Older daemon with no `plane` field: fall back to what we can observe. The
+  // engine's own state is asked FIRST — "stopped" is the answer that matters, and
+  // reading it off `running` is what used to make it unreachable (see engineState).
+  if (engineState(status) === 'down') {
+    return {
+      variant: 'crit',
+      headline: 'Service stopped',
+      detail: 'The engine isn’t running, so traffic isn’t being proxied or filtered.',
+      alarm: true,
+    }
+  }
+  if (status.active && status.table) {
     return {
       variant: 'on',
       headline: 'Protected',
@@ -110,14 +170,6 @@ export function protectionState(status: Status | null): ProtectionState {
       alarm: false,
     }
   }
-  if (!status.running) {
-    return {
-      variant: 'crit',
-      headline: 'Service stopped',
-      detail: 'The service isn’t running, so traffic isn’t being handled.',
-      alarm: true,
-    }
-  }
   return {
     variant: 'amber',
     headline: 'Starting up',

protocol/group/awg_selector_guard.go

@@ -1,93 +0,0 @@
-// lx:begin awg
-
-package group
-
-import (
-	"github.com/sagernet/sing-box/adapter"
-	C "github.com/sagernet/sing-box/constant"
-)
-
-// suspendAmneziaWGConsumersOnWireGuardSwitch is called from Selector.SelectOutbound
-// BEFORE the switch is committed. If the member about to be selected is — or chains
-// down via detour to — a WireGuard-based endpoint (type "wireguard", covering plain
-// WG and AmneziaWG), it walks UP from this group to every AmneziaWG endpoint that
-// detours through it and suspends each one (brings its device down). Rationale:
-// AmneziaWG traffic encapsulated inside a WireGuard tunnel hangs the kernel on
-// Android; the static Start-guard cannot cover this because a selector's chosen
-// member is only known at runtime.
-//
-// Called before s.selected is updated, so the race is closed: once the group
-// points at the WireGuard member, the AmneziaWG consumers are already suspended
-// (started=false) and a concurrent reconnect fails with "not ready" instead of
-// sending a junk handshake into WireGuard.
-func suspendAmneziaWGConsumersOnWireGuardSwitch(outboundManager adapter.OutboundManager, groupTag string, selected adapter.Outbound) {
-	if outboundManager == nil || groupTag == "" {
-		return
-	}
-	if !chainReachesWireGuard(outboundManager, selected, make(map[string]bool)) {
-		return
-	}
-	suspendAmneziaWGConsumers(outboundManager, groupTag, make(map[string]bool))
-}
-
-// chainReachesWireGuard reports whether outbound is — or transitively detours
-// down to, or (being a group) contains a member that is — a WireGuard-based
-// endpoint. visited guards against cycles.
-func chainReachesWireGuard(outboundManager adapter.OutboundManager, outbound adapter.Outbound, visited map[string]bool) bool {
-	if outbound == nil {
-		return false
-	}
-	tag := outbound.Tag()
-	if tag != "" {
-		if visited[tag] {
-			return false
-		}
-		visited[tag] = true
-	}
-	if outbound.Type() == C.TypeWireGuard {
-		return true
-	}
-	// Down the detour chain (vless -> ... -> wireguard).
-	for _, dependency := range outbound.Dependencies() {
-		if member, loaded := outboundManager.Outbound(dependency); loaded {
-			if chainReachesWireGuard(outboundManager, member, visited) {
-				return true
-			}
-		}
-	}
-	// A nested group: any member reaching WireGuard counts.
-	if group, isGroup := outbound.(adapter.OutboundGroup); isGroup {
-		for _, memberTag := range group.All() {
-			if member, loaded := outboundManager.Outbound(memberTag); loaded {
-				if chainReachesWireGuard(outboundManager, member, visited) {
-					return true
-				}
-			}
-		}
-	}
-	return false
-}
-
-// suspendAmneziaWGConsumers walks UP from tag via the reverse-dependency ledger
-// (ConsumersOf) and suspends every AmneziaWG endpoint that detours through it,
-// directly or transitively (e.g. AWG -> vless -> group). visited guards cycles.
-func suspendAmneziaWGConsumers(outboundManager adapter.OutboundManager, tag string, visited map[string]bool) {
-	for _, consumerTag := range outboundManager.ConsumersOf(tag) {
-		if visited[consumerTag] {
-			continue
-		}
-		visited[consumerTag] = true
-		consumer, loaded := outboundManager.Outbound(consumerTag)
-		if !loaded {
-			continue
-		}
-		if awg, isAWG := consumer.(adapter.AmneziaWGSuspendable); isAWG && awg.IsAmneziaWG() {
-			awg.SuspendAmneziaWG()
-		}
-		// Keep walking up: a non-AWG hop (vless) or a parent group may itself have
-		// an AmneziaWG consumer above it.
-		suspendAmneziaWGConsumers(outboundManager, consumerTag, visited)
-	}
-}
-
-// lx:end awg

protocol/group/awg_selector_guard_test.go

@@ -1,120 +0,0 @@
-// lx:begin awg
-
-package group
-
-import (
-	"testing"
-
-	"github.com/sagernet/sing-box/adapter"
-	C "github.com/sagernet/sing-box/constant"
-)
-
-// fakeOutbound is a minimal adapter.Outbound; only Type/Tag/Dependencies are read.
-type fakeOutbound struct {
-	adapter.Outbound
-	tag         string
-	outboundTyp string
-	detour      string
-}
-
-func (o *fakeOutbound) Type() string { return o.outboundTyp }
-func (o *fakeOutbound) Tag() string  { return o.tag }
-func (o *fakeOutbound) Dependencies() []string {
-	if o.detour == "" {
-		return nil
-	}
-	return []string{o.detour}
-}
-
-// fakeAWG implements adapter.AmneziaWGSuspendable and records suspension.
-type fakeAWG struct {
-	fakeOutbound
-	awg       bool
-	suspended bool
-}
-
-func (a *fakeAWG) IsAmneziaWG() bool { return a.awg }
-func (a *fakeAWG) SuspendAmneziaWG() { a.suspended = true }
-
-// fakeManager resolves tags and reverse-deps (ConsumersOf) from fixed maps.
-type fakeManager struct {
-	adapter.OutboundManager
-	byTag     map[string]adapter.Outbound
-	consumers map[string][]string
-}
-
-func (m *fakeManager) Outbound(tag string) (adapter.Outbound, bool) {
-	ob, ok := m.byTag[tag]
-	return ob, ok
-}
-func (m *fakeManager) ConsumersOf(tag string) []string { return m.consumers[tag] }
-
-func TestChainReachesWireGuard(t *testing.T) {
-	wg := &fakeOutbound{tag: "wg", outboundTyp: C.TypeWireGuard}
-	vlessToWG := &fakeOutbound{tag: "v2wg", outboundTyp: C.TypeVLESS, detour: "wg"}
-	vlessLeaf := &fakeOutbound{tag: "vleaf", outboundTyp: C.TypeVLESS}
-	mgr := &fakeManager{byTag: map[string]adapter.Outbound{
-		"wg": wg, "v2wg": vlessToWG, "vleaf": vlessLeaf,
-	}}
-
-	if !chainReachesWireGuard(mgr, wg, map[string]bool{}) {
-		t.Fatal("direct wireguard member must reach wireguard")
-	}
-	if !chainReachesWireGuard(mgr, vlessToWG, map[string]bool{}) {
-		t.Fatal("vless detouring to wireguard must reach wireguard")
-	}
-	if chainReachesWireGuard(mgr, vlessLeaf, map[string]bool{}) {
-		t.Fatal("plain vless must not reach wireguard")
-	}
-}
-
-func TestSuspendAmneziaWGConsumers(t *testing.T) {
-	// awg-direct detours through the group "sel"
-	awgDirect := &fakeAWG{fakeOutbound: fakeOutbound{tag: "awg-direct", outboundTyp: C.TypeWireGuard, detour: "sel"}, awg: true}
-	// awg-via-hop -> vless-hop -> sel
-	awgViaHop := &fakeAWG{fakeOutbound: fakeOutbound{tag: "awg-hop", outboundTyp: C.TypeWireGuard, detour: "vless-hop"}, awg: true}
-	vlessHop := &fakeOutbound{tag: "vless-hop", outboundTyp: C.TypeVLESS, detour: "sel"}
-	// plain-wg detours through sel but is NOT amneziawg — must stay untouched
-	plainWG := &fakeAWG{fakeOutbound: fakeOutbound{tag: "plain-wg", outboundTyp: C.TypeWireGuard, detour: "sel"}, awg: false}
-
-	mgr := &fakeManager{
-		byTag: map[string]adapter.Outbound{
-			"awg-direct": awgDirect, "awg-hop": awgViaHop,
-			"vless-hop": vlessHop, "plain-wg": plainWG,
-		},
-		consumers: map[string][]string{
-			"sel":       {"awg-direct", "vless-hop", "plain-wg"},
-			"vless-hop": {"awg-hop"},
-		},
-	}
-
-	suspendAmneziaWGConsumers(mgr, "sel", map[string]bool{})
-
-	if !awgDirect.suspended {
-		t.Error("direct AmneziaWG consumer must be suspended")
-	}
-	if !awgViaHop.suspended {
-		t.Error("transitive AmneziaWG consumer (via vless hop) must be suspended")
-	}
-	if plainWG.suspended {
-		t.Error("plain (non-AmneziaWG) wireguard consumer must NOT be suspended")
-	}
-}
-
-// A switch to a non-wireguard member must suspend nothing.
-func TestSuspendSkippedForNonWireGuardSwitch(t *testing.T) {
-	awg := &fakeAWG{fakeOutbound: fakeOutbound{tag: "awg", outboundTyp: C.TypeWireGuard, detour: "sel"}, awg: true}
-	vlessLeaf := &fakeOutbound{tag: "vleaf", outboundTyp: C.TypeVLESS}
-	mgr := &fakeManager{
-		byTag:     map[string]adapter.Outbound{"awg": awg, "vleaf": vlessLeaf},
-		consumers: map[string][]string{"sel": {"awg"}},
-	}
-
-	// selected member is plain vless (does not reach wireguard) → no suspension
-	suspendAmneziaWGConsumersOnWireGuardSwitch(mgr, "sel", vlessLeaf)
-	if awg.suspended {
-		t.Error("must not suspend when the selected member does not reach wireguard")
-	}
-}
-
-// lx:end awg

protocol/group/selector.go

@@ -128,16 +128,6 @@ func (s *Selector) SelectOutbound(tag string) bool {
 	if s.selected.Load() == detour {
 		return true
 	}
-	// lx:begin awg
-	// Suspend AmneziaWG consumers BEFORE switching: if the new member is (or chains
-	// to) a WireGuard endpoint, any AmneziaWG endpoint that detours through this
-	// group would tunnel AWG inside WireGuard and hang the kernel on Android. Doing
-	// this before s.selected.Swap closes the race — by the time the group points at
-	// the WireGuard member, those consumers are already down (started=false), so a
-	// concurrent reconnect fails with "not ready" instead of sending a junk
-	// handshake into WireGuard.
-	suspendAmneziaWGConsumersOnWireGuardSwitch(s.outbound, s.Tag(), detour)
-	// lx:end awg
 	s.selected.Store(detour)
 	invalidateReachability(s.ctx) // lx: SPEC 020 — active selection changed
 	if s.Tag() != "" {

protocol/group/urltest.go

@@ -51,6 +51,13 @@ type URLTest struct {
 	// path that does not go through NewURLTest (hand-built groups in tests).
 	// See option.URLTestOutboundOptions.SelfCheck for the full reasoning.
 	selfCheckDisabled bool
+	// lx: health board §5.C — the RUNTIME half of the same question, read from
+	// the context registry at construction. selfCheckDisabled above says "this
+	// group is not used by the config"; this says "this group cannot be reached
+	// right now", which changes while the box runs and is therefore asked
+	// afresh at every scheduled check rather than stored. nil = no gate.
+	// See urltest.ProbeGate for why the two must stay separate.
+	probeGate urltest.ProbeGate
 }
 
 func NewURLTest(ctx context.Context, router adapter.Router, logger log.ContextLogger, tag string, options option.URLTestOutboundOptions) (adapter.Outbound, error) {
@@ -81,6 +88,9 @@ func NewURLTest(ctx context.Context, router adapter.Router, logger log.ContextLo
 		// nil/absent means true (self-check on) — the documented default, so a
 		// config written before the flag existed behaves exactly as it always has.
 		selfCheckDisabled: options.SelfCheck != nil && !*options.SelfCheck,
+		// Absent from the registry (plain sing-box, tests) yields nil, which
+		// means "no gate" — every scheduled probe proceeds, as before.
+		probeGate: service.FromContext[urltest.ProbeGate](ctx),
 	}
 	if len(outbound.tags) == 0 {
 		return nil, E.New("missing tags")
@@ -105,6 +115,10 @@ func (s *URLTest) Start() error {
 	// lx: health board §5.C — carry the stand-down flag onto the group the same
 	// way the balancer travels: set after construction, immutable from then on.
 	group.selfCheckDisabled = s.selfCheckDisabled
+	// The gate and the tag to ask it about travel together: the gate answers
+	// per-outbound, and the group is the thing whose schedule is being gated.
+	group.probeGate = s.probeGate
+	group.tag = s.Tag()
 	if s.balancer != nil {
 		// lx: health board §5.B — slot liveness reads through the board verdict, so a
 		// death recorded by any prober or a failed dial takes effect on the next pick,
@@ -135,12 +149,14 @@ func (s *URLTest) Now() string {
 	if s.balancer != nil {
 		return s.group.lastSelected.Load()
 	}
-	if s.group.selectedOutboundTCP != nil {
-		return s.group.selectedOutboundTCP.Tag()
-	} else if s.group.selectedOutboundUDP != nil {
-		return s.group.selectedOutboundUDP.Tag()
+	// One load, so the two halves reported here are the SAME decision.
+	selected := s.group.selected.Load()
+	if selected.tcp != nil {
+		return selected.tcp.Tag()
+	} else if selected.udp != nil {
+		return selected.udp.Tag()
 	}
-	// lx: SPEC 019 — cold start: before the first URL-test, selectedOutbound* is nil but
+	// lx: SPEC 019 — cold start: before the first URL-test the pair is empty but
 	// traffic already flows via the Select() fallback (outbounds[0] when no history yet).
 	// Mirror exactly what the next DialContext would pick, so the UI shows the real node
 	// instead of blank. Select() is the same source of truth DialContext uses.
@@ -321,14 +337,39 @@ type URLTestGroup struct {
 	idleTimeout   time.Duration
 	history       *urltest.HistoryStorage
 	checking      atomic.Bool
-	selectedOutboundTCP          adapter.Outbound
-	selectedOutboundUDP          adapter.Outbound
+	// selected is the least_test cache: the member this group currently prefers, per
+	// network. It is written by the probing goroutine and read on EVERY dial through
+	// the group (selectExcluding / dialSelect) and by the panel (Now), so it is an
+	// atomic value rather than two plain fields — the same thing Selector does one file
+	// over (selector.go, common.TypedValue[adapter.Outbound]). An interface field is two
+	// words; a torn read of one hands a dial a type descriptor with the wrong data
+	// pointer, which is not a wrong node but a corrupt one.
+	//
+	// The TCP and UDP halves live in ONE value on purpose. They are decided together, by
+	// one pass over one board reading, and publishing them separately let a reader pick
+	// up the new TCP choice against the previous UDP choice — the group's hysteresis
+	// silently applied to a decision that was never made.
+	selected                     common.TypedValue[selectedPair]
 	interruptGroup               *interrupt.Group
 	interruptExternalConnections bool
 	access                       sync.Mutex
 	ticker                       *time.Ticker
 	close                        chan struct{}
-	started                      bool
+	// started is read by Touch on every dial, outside g.access, and written by
+	// PostStart under it — an atomic because that is what it always was in effect.
+	started atomic.Bool
+	// closed latches in Close and is what makes Close FINAL. Guarded by access.
+	//
+	// It exists because "has a ticker" is not the same question as "is shut down", and
+	// Close used to ask the first one: with no ticker armed it returned before closing
+	// g.close, leaving the group indistinguishable from a running one. A Touch arriving
+	// afterwards — an outbound snapshot taken before an Apply is still dialable for up
+	// to two minutes, see shater/engine/grouptest.go — then armed a fresh ticker whose
+	// loopCheck waits on a channel nobody will ever close, in a box whose context is
+	// already cancelled. Every tick of it fails instantly and files a "dead" verdict on
+	// the SHARED health board that the live generation selects nodes from. One retired
+	// group can go on declaring the whole node set dead for the uptime of the daemon.
+	closed       bool
 	lastActive   common.TypedValue[time.Time]
 	lastSelected common.TypedValue[string] // lx: SPEC 019 — Now() in balanced modes
 	balancer     *balancer                 // lx: SPEC 019 v2 — round_robin pool; nil for least_test
@@ -338,6 +379,101 @@ type URLTestGroup struct {
 	// explicit CheckOutbounds/URLTest call is untouched — the flag stands down
 	// the schedule, not the capability.
 	selfCheckDisabled bool
+	// lx: health board §5.C — the runtime gate and the tag it is asked about.
+	// Both mirror URLTest's fields (set by Start, immutable afterwards); nil
+	// gate or empty tag means every scheduled check proceeds. Consulted only
+	// through selfCheckAllowed, and only on the SCHEDULE.
+	probeGate urltest.ProbeGate
+	tag       string
+}
+
+// selectedPair is one published least_test decision: the member chosen for TCP and the
+// member chosen for UDP, as of the same probing round. Either half may be nil (nothing
+// picked yet for that network).
+type selectedPair struct {
+	tcp adapter.Outbound
+	udp adapter.Outbound
+}
+
+// selectedFor returns the cached choice for one network (nil when there is none, or when
+// network is neither TCP nor UDP — the caller then falls through to a fresh selection).
+func (g *URLTestGroup) selectedFor(network string) adapter.Outbound {
+	pair := g.selected.Load()
+	switch network {
+	case N.NetworkTCP:
+		return pair.tcp
+	case N.NetworkUDP:
+		return pair.udp
+	}
+	return nil
+}
+
+// setSelected publishes a decision. It is the ONLY writer of g.selected, and it writes
+// the pair whole — see the field comment for why the two halves may not be split.
+func (g *URLTestGroup) setSelected(tcp, udp adapter.Outbound) {
+	g.selected.Store(selectedPair{tcp: tcp, udp: udp})
+}
+
+// selfCheckAllowed reports whether the group's OWN probing schedule may dial
+// right now. lx: health board §5.C.
+//
+// Two independent refusals, in the order they can be answered cheapest first:
+//
+//	selfCheckDisabled — the config says no rule reaches this group. Fixed for
+//	                    the life of the box; see standDownUnusedSelfCheck.
+//	probeGate         — the world says this group cannot be reached right now,
+//	                    typically a chain hop sitting behind a dead hop. Asked
+//	                    fresh EVERY time, which is the entire mechanism by which
+//	                    a recovered hop resumes probing: there is no state here
+//	                    to reset, so there is none to get stuck.
+//
+// Neither refusal touches an explicit CheckOutbounds/URLTest — a deliberate
+// request is never a scheduled one.
+func (g *URLTestGroup) selfCheckAllowed() bool {
+	if g.selfCheckDisabled {
+		return false
+	}
+	if g.probeGate == nil || g.tag == "" {
+		return true
+	}
+	return g.probeGate.ProbeAllowed(g.tag)
+}
+
+// scheduledCheck is one firing of the group's own schedule — the warm-up sweep
+// and every ticker tick go through here, and nothing else does. Having exactly
+// one gated entry point is what keeps the two callers from drifting apart, and
+// it is the seam the tests drive to assert that a gated group makes no dial
+// attempt at all.
+func (g *URLTestGroup) scheduledCheck() {
+	if !g.selfCheckAllowed() {
+		return
+	}
+	g.CheckOutbounds(false)
+}
+
+// keepWarm reports whether this group must keep measuring with no traffic
+// flowing through it. lx: health board §5.C — see urltest.ProbeGate.ProbeWhenIdle.
+//
+// The default is NO, in every direction: no gate, no tag, or a group whose
+// self-check is stood down anyway. Only a gate that positively says "the routing
+// config reaches this group" turns the idle timeout off, so plain sing-box and
+// every hand-built group keep the lifecycle they have always had.
+func (g *URLTestGroup) keepWarm() bool {
+	if g.selfCheckDisabled || g.probeGate == nil || g.tag == "" {
+		return false
+	}
+	return g.probeGate.ProbeWhenIdle(g.tag)
+}
+
+// startTickerLocked arms the group's own probing ticker. g.access MUST be held
+// and g.ticker MUST be nil. Extracted so PostStart and Touch arm it identically
+// — two ways in, one construction, no chance of one of them forgetting the pause
+// registration.
+func (g *URLTestGroup) startTickerLocked() {
+	ticker := time.NewTicker(g.interval)
+	g.ticker = ticker
+	g.pauseCallback = pause.RegisterTicker(g.pause, ticker, g.interval, nil)
+	go g.loopCheck(ticker, g.close)
 }
 
 func NewURLTestGroup(ctx context.Context, outboundManager adapter.OutboundManager, logger log.Logger, outbounds []adapter.Outbound, link string, interval time.Duration, tolerance uint16, idleTimeout time.Duration, interruptExternalConnections bool) (*URLTestGroup, error) {
@@ -377,7 +513,10 @@ func NewURLTestGroup(ctx context.Context, outboundManager adapter.OutboundManage
 func (g *URLTestGroup) PostStart() {
 	g.access.Lock()
 	defer g.access.Unlock()
-	g.started = true
+	if g.closed {
+		return
+	}
+	g.started.Store(true)
 	g.lastActive.Store(time.Now())
 	// lx: SPEC 019 v2 — seed the pool so round_robin can route from the first connection,
 	// before the first health-check completes (history-warm nodes first, else config order).
@@ -391,13 +530,31 @@ func (g *URLTestGroup) PostStart() {
 	// exists to keep honest. A stood-down group therefore skips it entirely; the
 	// observatory (or nothing, for a truly unused group) is what measures its
 	// members.
-	if !g.selfCheckDisabled {
-		go g.CheckOutbounds(false)
+	//
+	// The same call is now also where a chain hop behind a DEAD hop declines to
+	// sweep: every member of such a group dials through the broken hop, so the
+	// sweep would measure that hop once per member and file the result against
+	// this one. selfCheckAllowed keeps both refusals in one place.
+	go g.scheduledCheck()
+	// A group the routing config REACHES keeps measuring whether or not anybody
+	// dials it, so its ticker is armed here instead of waiting for a Touch that
+	// may never come. Without this, a used group with no traffic gets this one
+	// warm-up sweep and then nothing: its members age past the verdict TTL and
+	// the panel reports "untested" about a rule that is in force, while the first
+	// real request pays a cold probe. Nothing else would fill the gap — the
+	// observatory stands off a urltest group's members entirely (probeplan.go
+	// SelfChecked), which is the whole point of one dialler per target.
+	//
+	// lastActive was stored a moment ago, so loopCheck's opening "idle longer
+	// than the interval" check does not fire and this cannot double up with the
+	// sweep above.
+	if g.keepWarm() && g.ticker == nil {
+		g.startTickerLocked()
 	}
 }
 
 func (g *URLTestGroup) Touch() {
-	if !g.started {
+	if !g.started.Load() {
 		return
 	}
 	// lx: health board §5.C — Touch's only job is to keep the group's OWN
@@ -407,32 +564,61 @@ func (g *URLTestGroup) Touch() {
 	// manual pin) must not arm 30 minutes of direct probing under the members'
 	// base tags. Checked before the lock because the flag is immutable after
 	// Start, exactly like the started fast-path above.
+	//
+	// The runtime gate is deliberately NOT consulted here. Touch only arms the
+	// ticker; refusing to arm it would mean a hop that recovers has no ticker
+	// left to notice — the block would outlive the failure, which is the one
+	// outcome this must never have. The ticker runs and each tick re-asks the
+	// gate (loopCheck -> scheduledCheck), so a blocked hop costs a predicate
+	// call per interval and resumes the moment the hop in front answers.
 	if g.selfCheckDisabled {
 		return
 	}
 	g.access.Lock()
 	defer g.access.Unlock()
+	// A closed group arms nothing. Touch is reachable long after Close — a caller
+	// holding an outbound from a snapshot taken before an Apply keeps dialling it (up
+	// to the 120s budget of shater/engine/grouptest.go) — and the ticker it would arm
+	// has no way left to stop: see the `closed` field for what that costs.
+	if g.closed {
+		return
+	}
 	if g.ticker != nil {
 		g.lastActive.Store(time.Now())
 		return
 	}
-	ticker := time.NewTicker(g.interval)
-	g.ticker = ticker
-	g.pauseCallback = pause.RegisterTicker(g.pause, ticker, g.interval, nil)
-	go g.loopCheck(ticker, g.close)
+	g.startTickerLocked()
 }
 
+// Close shuts the group down for good. It is idempotent, and it is FINAL: no later Touch
+// can bring the probing schedule back.
+//
+// It used to return early when no ticker happened to be armed, without ever closing
+// g.close — so a group that was closed while idle stayed, from the point of view of every
+// other method, a perfectly live group. That is the whole defect: the close channel is the
+// only way a loopCheck goroutine ever exits (its idle-timeout escape does not fire for a
+// group the routing config reaches, keepWarm), so a ticker armed after such a Close is
+// immortal, and every one of its ticks writes a failure to the shared health board on
+// behalf of a box that no longer exists.
 func (g *URLTestGroup) Close() error {
 	g.access.Lock()
 	defer g.access.Unlock()
-	if g.ticker == nil {
+	if g.closed {
 		return nil
 	}
+	g.closed = true
+	// Unconditionally, BEFORE looking at the ticker: this is the signal every loopCheck
+	// waits on, including any that a Touch armed after the last one was retired by the
+	// idle timeout.
+	if g.close != nil {
+		close(g.close)
+	}
+	if g.ticker != nil {
 		g.ticker.Stop()
 		g.ticker = nil
 		g.pause.UnregisterCallback(g.pauseCallback)
 		g.pauseCallback = nil
-	close(g.close)
+	}
 	return nil
 }
 
@@ -445,10 +631,15 @@ func (g *URLTestGroup) Select(network string) (adapter.Outbound, bool) {
 	return g.selectExcluding(network, nil)
 }
 
+// loopCheck is the group's own schedule. lx: health board §5.C — every probe it
+// fires goes through scheduledCheck, so a stood-down or currently-unreachable
+// group ticks without dialling. The ticker's LIFECYCLE (the idle timeout below)
+// is deliberately left alone: a gated group keeps its ticker exactly as long as
+// an ungated one would, because the ticker is what will notice the recovery.
 func (g *URLTestGroup) loopCheck(ticker *time.Ticker, closeChan <-chan struct{}) {
 	if time.Since(g.lastActive.Load()) > g.interval {
 		g.lastActive.Store(time.Now())
-		g.CheckOutbounds(false)
+		g.scheduledCheck()
 	}
 	for {
 		select {
@@ -456,7 +647,13 @@ func (g *URLTestGroup) loopCheck(ticker *time.Ticker, closeChan <-chan struct{})
 			return
 		case <-ticker.C:
 		}
-		if time.Since(g.lastActive.Load()) > g.idleTimeout {
+		// The idle timeout retires the ticker of a group nobody is dialling —
+		// unless the routing config reaches it, in which case its health is a
+		// live question whether or not traffic is flowing and the ticker must
+		// outlive the silence. Asked here rather than remembered from PostStart
+		// so it tracks the running config, and asked OUTSIDE g.access because the
+		// answer comes from the engine, which has locks of its own.
+		if !g.keepWarm() && time.Since(g.lastActive.Load()) > g.idleTimeout {
 			g.access.Lock()
 			if g.ticker == ticker {
 				g.ticker.Stop()
@@ -467,7 +664,7 @@ func (g *URLTestGroup) loopCheck(ticker *time.Ticker, closeChan <-chan struct{})
 			g.access.Unlock()
 			return
 		}
-		g.CheckOutbounds(false)
+		g.scheduledCheck()
 	}
 }
 
@@ -565,19 +762,29 @@ func (g *URLTestGroup) testNodes(ctx context.Context, outbounds []adapter.Outbou
 	return result
 }
 
+// performUpdateCheck re-ranks the members after a probing round and publishes the result.
+// It is the only writer of g.selected: it reads the current pair ONCE, decides both
+// networks against that one snapshot, and stores the outcome as a single value, so no
+// reader can ever observe a half-applied decision. Callers are serialised by g.checking
+// (urlTest), which is what makes the read-decide-store sequence safe without a lock.
 func (g *URLTestGroup) performUpdateCheck() {
+	current := g.selected.Load()
+	next := current
 	var updated bool
-	if outbound, exists := g.Select(N.NetworkTCP); outbound != nil && (g.selectedOutboundTCP == nil || (exists && outbound != g.selectedOutboundTCP)) {
-		if g.selectedOutboundTCP != nil {
+	if outbound, exists := g.Select(N.NetworkTCP); outbound != nil && (current.tcp == nil || (exists && outbound != current.tcp)) {
+		if current.tcp != nil {
 			updated = true
 		}
-		g.selectedOutboundTCP = outbound
+		next.tcp = outbound
 	}
-	if outbound, exists := g.Select(N.NetworkUDP); outbound != nil && (g.selectedOutboundUDP == nil || (exists && outbound != g.selectedOutboundUDP)) {
-		if g.selectedOutboundUDP != nil {
+	if outbound, exists := g.Select(N.NetworkUDP); outbound != nil && (current.udp == nil || (exists && outbound != current.udp)) {
+		if current.udp != nil {
 			updated = true
 		}
-		g.selectedOutboundUDP = outbound
+		next.udp = outbound
+	}
+	if next != current {
+		g.setSelected(next.tcp, next.udp)
 	}
 	if updated {
 		g.interruptGroup.Interrupt(g.interruptExternalConnections)

protocol/group/urltest_health_lx.go

@@ -74,13 +74,7 @@ func (g *URLTestGroup) selectExcluding(network string, exclude map[string]bool)
 	var minOutbound adapter.Outbound
 	// Keep the upstream hysteresis: the currently selected outbound only yields to a
 	// member faster by more than tolerance — but only while it is still alive itself.
-	var current adapter.Outbound
-	switch network {
-	case N.NetworkTCP:
-		current = g.selectedOutboundTCP
-	case N.NetworkUDP:
-		current = g.selectedOutboundUDP
-	}
+	current := g.selectedFor(network)
 	if current != nil {
 		currentTag := RealTag(current)
 		if !exclude[currentTag] && g.history.Verdict(currentTag, ttl) == urltest.VerdictAlive {
@@ -144,13 +138,7 @@ func (s *URLTest) dialSelect(ctx context.Context, network string, destination M.
 	if s.balancer != nil {
 		return s.selectBalanced(ctx, network, destination, tried)
 	}
-	var outbound adapter.Outbound
-	switch N.NetworkName(network) {
-	case N.NetworkTCP:
-		outbound = s.group.selectedOutboundTCP
-	case N.NetworkUDP:
-		outbound = s.group.selectedOutboundUDP
-	}
+	outbound := s.group.selectedFor(N.NetworkName(network))
 	if outbound != nil {
 		realTag := RealTag(outbound)
 		if !tried[realTag] && s.group.history.Verdict(realTag, s.group.healthTTL()) != urltest.VerdictDead {

protocol/group/urltest_health_lx_test.go

@@ -7,6 +7,7 @@ import (
 	"context"
 	"errors"
 	"net"
+	"sync"
 	"testing"
 	"time"
 
@@ -32,10 +33,31 @@ type healthNode struct {
 func (n *healthNode) Tag() string       { return n.tag }
 func (n *healthNode) Network() []string { return []string{N.NetworkTCP, N.NetworkUDP} }
 
-func (n *healthNode) DialContext(ctx context.Context, network string, destination M.Socksaddr) (net.Conn, error) {
-	if n.dialed != nil {
-		*n.dialed = append(*n.dialed, n.tag)
+// healthDialMu guards the shared dialed slice. testNodes probes a group's
+// members CONCURRENTLY (a batch of 10), so two nodes pointing at one slice
+// append from two goroutines; the append is what the -race build trips on, not
+// the code under test.
+var healthDialMu sync.Mutex
+
+func (n *healthNode) record() {
+	if n.dialed == nil {
+		return
 	}
+	healthDialMu.Lock()
+	*n.dialed = append(*n.dialed, n.tag)
+	healthDialMu.Unlock()
+}
+
+// dialsOf reads a dial log under the same lock. Every assertion on a log a
+// concurrent sweep may still be writing must go through it.
+func dialsOf(dialed *[]string) []string {
+	healthDialMu.Lock()
+	defer healthDialMu.Unlock()
+	return append([]string(nil), *dialed...)
+}
+
+func (n *healthNode) DialContext(ctx context.Context, network string, destination M.Socksaddr) (net.Conn, error) {
+	n.record()
 	if n.fail {
 		return nil, errors.New("dial refused")
 	}
@@ -45,9 +67,7 @@ func (n *healthNode) DialContext(ctx context.Context, network string, destinatio
 }
 
 func (n *healthNode) ListenPacket(ctx context.Context, destination M.Socksaddr) (net.PacketConn, error) {
-	if n.dialed != nil {
-		*n.dialed = append(*n.dialed, n.tag)
-	}
+	n.record()
 	if n.fail {
 		return nil, errors.New("listen refused")
 	}
@@ -85,6 +105,9 @@ func healthTestGroup(hist *urltest.HistoryStorage, manager adapter.OutboundManag
 		tolerance:      50,
 		logger:         log.NewNOPFactory().Logger(),
 		interruptGroup: interrupt.NewGroup(),
+		// Real groups always have this channel (NewURLTestGroup); it is what Close
+		// signals every loopCheck through, so a hand-built group needs it too.
+		close: make(chan struct{}),
 	}
 }
 
@@ -161,7 +184,7 @@ func TestSelectHysteresisKeepsAliveCurrent(t *testing.T) {
 	hist := urltest.NewHistoryStorage()
 	a, b := &balNode{tag: "a"}, &balNode{tag: "b"}
 	g := healthTestGroup(hist, nil, a, b)
-	g.selectedOutboundTCP = a
+	g.setSelected(a, nil)
 	storeAlive(hist, "a", 100)
 	storeAlive(hist, "b", 60) // within tolerance (100 ≤ 60+50) → keep a
 	if selected, _ := g.Select(N.NetworkTCP); selected != adapter.Outbound(a) {
@@ -178,7 +201,7 @@ func TestSelectDeadCurrentLosesToAlive(t *testing.T) {
 	hist := urltest.NewHistoryStorage()
 	a, b := &balNode{tag: "a"}, &balNode{tag: "b"}
 	g := healthTestGroup(hist, nil, a, b)
-	g.selectedOutboundTCP = a
+	g.setSelected(a, nil)
 	storeAlive(hist, "a", 10)
 	hist.MarkFailed("a")
 	storeAlive(hist, "b", 500)
@@ -331,7 +354,7 @@ func TestDialContextRetriesThroughNextAlive(t *testing.T) {
 	s := healthURLTest(g, nil, nil)
 	storeAlive(hist, "a", 10)
 	storeAlive(hist, "b", 100)
-	g.selectedOutboundTCP = a // the checker had picked a; it dies between ticks
+	g.setSelected(a, nil) // the checker had picked a; it dies between ticks
 	conn, err := s.DialContext(context.Background(), N.NetworkTCP, destDomain("example.com"))
 	if err != nil {
 		t.Fatalf("DialContext failed despite live member b: %v", err)
@@ -427,7 +450,7 @@ func TestListenPacketRetriesBeforeFirstSend(t *testing.T) {
 	s := healthURLTest(g, nil, nil)
 	storeAlive(hist, "a", 10)
 	storeAlive(hist, "b", 100)
-	g.selectedOutboundUDP = a
+	g.setSelected(nil, a)
 	conn, err := s.ListenPacket(context.Background(), destDomain("example.com"))
 	if err != nil {
 		t.Fatalf("ListenPacket failed despite live member b: %v", err)

protocol/group/urltest_race_lx_test.go

@@ -0,0 +1,330 @@
+package group
+
+// Concurrency tests for the urltest group: the group's own probing schedule running at
+// the same time as traffic going through it.
+//
+// This combination had no coverage at all. Every existing test either probes OR dials,
+// never both at once, so the race detector had nothing to detect: the cached least_test
+// choice was written by the prober goroutine and read on every single dial, with no
+// synchronisation whatsoever, and the suite stayed green for as long as those two things
+// never happened in the same test.
+//
+// An unsynchronised interface field is not a "usually fine" race. It is two words — type
+// descriptor and data pointer — and a reader that catches the store half way holds a
+// descriptor addressing the wrong value. What comes out is not a suboptimal node, it is a
+// corrupt one, on the path of every connection the group carries.
+
+import (
+	"context"
+	"sync"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"github.com/sagernet/sing-box/adapter"
+	"github.com/sagernet/sing-box/common/urltest"
+	M "github.com/sagernet/sing/common/metadata"
+	N "github.com/sagernet/sing/common/network"
+	"github.com/sagernet/sing/service/pause"
+)
+
+// TestURLTestDialRacesProbeTicker drives real dials through a least_test group while the
+// group's own probing schedule keeps re-deciding which member to use — the situation on
+// every router where a urltest group carries traffic, since the ticker fires on its own
+// interval regardless of what the connections are doing.
+//
+// It is a -race test first and an assertion test second: the failure it was written for
+// is reported by the detector, not by a wrong value. Run it under -race or it proves
+// almost nothing (the gate's [4/4] pass does).
+func TestURLTestDialRacesProbeTicker(t *testing.T) {
+	hist := urltest.NewHistoryStorage()
+	a, b := &healthNode{tag: "a"}, &healthNode{tag: "b"}
+	manager := managerOf(a, b)
+	g := healthTestGroup(hist, manager, a, b)
+	s := healthURLTest(g, nil, manager)
+	storeAlive(hist, "a", 20)
+	storeAlive(hist, "b", 500)
+
+	var proberWG, dialWG sync.WaitGroup
+	stop := make(chan struct{})
+
+	// The prober: one full turn of the group's own schedule per iteration. CheckOutbounds
+	// is the real tick (probe every member, then publish); the probes cannot reach
+	// anything from a unit test, so the board is then re-armed with a winner that MOVES
+	// and the publish step is run again — otherwise the cached choice is written once and
+	// the window in which a reader can catch a torn write is a few nanoseconds wide.
+	proberWG.Add(1)
+	go func() {
+		defer proberWG.Done()
+		for i := 0; ; i++ {
+			select {
+			case <-stop:
+				return
+			default:
+			}
+			g.CheckOutbounds(true)
+			fast, slow := "a", "b"
+			if i%2 == 1 {
+				fast, slow = "b", "a"
+			}
+			storeAlive(hist, fast, 20)
+			storeAlive(hist, slow, 500)
+			g.performUpdateCheck()
+		}
+	}()
+
+	// The traffic: every dial reads the cached choice (dialSelect), and so does the panel
+	// (Now). Both are the read side of the race.
+	var dials, nows atomic.Int64
+	for range 4 {
+		dialWG.Add(1)
+		go func() {
+			defer dialWG.Done()
+			for range 300 {
+				if conn, err := s.DialContext(context.Background(), N.NetworkTCP, M.Socksaddr{}); err == nil {
+					_ = conn.Close()
+					dials.Add(1)
+				}
+				if pc, err := s.ListenPacket(context.Background(), M.Socksaddr{}); err == nil {
+					_ = pc.Close()
+				}
+				// The panel polls this while everything above is happening.
+				if tag := s.Now(); tag != "" && tag != "a" && tag != "b" {
+					t.Errorf("Now() = %q, which is not a member of the group — a torn read of the cached choice", tag)
+				}
+				nows.Add(1)
+			}
+		}()
+	}
+
+	// The dialers are the bounded side; the prober runs until they are done.
+	dialersDone := make(chan struct{})
+	go func() { dialWG.Wait(); close(dialersDone) }()
+	select {
+	case <-dialersDone:
+	case <-time.After(60 * time.Second):
+		close(stop)
+		proberWG.Wait()
+		t.Fatal("dialers did not finish — the group deadlocked against its own prober")
+	}
+	close(stop)
+	proberWG.Wait()
+
+	if dials.Load() == 0 {
+		t.Fatal("no dial succeeded — the test never exercised the read side it exists to race")
+	}
+	if nows.Load() == 0 {
+		t.Fatal("Now() was never polled")
+	}
+}
+
+// TestSelectedPairPublishedTogether pins the pairing half of the same defect: the TCP and
+// UDP choices are one decision, taken from one board reading, and they become visible
+// together. They used to be two separate field writes, so a reader could take the new TCP
+// choice against the previous UDP one — a combination no probing round ever decided, and
+// the group's hysteresis silently applied to it.
+func TestSelectedPairPublishedTogether(t *testing.T) {
+	hist := urltest.NewHistoryStorage()
+	a, b := &healthNode{tag: "a"}, &healthNode{tag: "b"}
+	g := healthTestGroup(hist, managerOf(a, b), a, b)
+
+	// Round 1: a wins both networks.
+	storeAlive(hist, "a", 20)
+	storeAlive(hist, "b", 500)
+	g.performUpdateCheck()
+	if got := g.selected.Load(); got.tcp != adapter.Outbound(a) || got.udp != adapter.Outbound(a) {
+		t.Fatalf("after round 1 the pair is (%v, %v), want (a, a)", tagOrNil(got.tcp), tagOrNil(got.udp))
+	}
+
+	// Round 2: b wins both, by more than the tolerance.
+	storeAlive(hist, "a", 500)
+	storeAlive(hist, "b", 20)
+	g.performUpdateCheck()
+	got := g.selected.Load()
+	if got.tcp != adapter.Outbound(b) || got.udp != adapter.Outbound(b) {
+		t.Fatalf("after round 2 the pair is (%v, %v), want (b, b) — both halves move together",
+			tagOrNil(got.tcp), tagOrNil(got.udp))
+	}
+
+	// And what the dial path reads per network agrees with the published pair.
+	if g.selectedFor(N.NetworkTCP) != got.tcp || g.selectedFor(N.NetworkUDP) != got.udp {
+		t.Fatal("selectedFor disagrees with the published pair")
+	}
+	if g.selectedFor("icmp") != nil {
+		t.Fatal("selectedFor on an unknown network must yield nothing, not a TCP choice")
+	}
+}
+
+// TestURLTestGroupProbeRacesPanelRead is the narrower of the pair: the panel's Now() poll
+// against the prober, with no dialling at all. shater/engine/grouphealth.go,
+// shater/stats/stats.go and shater/engine/grouptest.go all call Now() from their own
+// goroutines while the group's ticker runs.
+func TestURLTestGroupProbeRacesPanelRead(t *testing.T) {
+	hist := urltest.NewHistoryStorage()
+	a, b := &healthNode{tag: "a"}, &healthNode{tag: "b"}
+	manager := managerOf(a, b)
+	g := healthTestGroup(hist, manager, a, b)
+	s := healthURLTest(g, nil, manager)
+
+	var wg sync.WaitGroup
+	stop := make(chan struct{})
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		for i := 0; ; i++ {
+			select {
+			case <-stop:
+				return
+			default:
+			}
+			fast, slow := "a", "b"
+			if i%2 == 1 {
+				fast, slow = "b", "a"
+			}
+			storeAlive(hist, fast, 20)
+			storeAlive(hist, slow, 500)
+			g.performUpdateCheck()
+		}
+	}()
+	for range 3 {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			for range 2000 {
+				_ = s.Now()
+			}
+		}()
+	}
+	time.Sleep(50 * time.Millisecond)
+	close(stop)
+	wg.Wait()
+}
+
+// tagOrNil renders a possibly-nil outbound for a failure message.
+func tagOrNil(o adapter.Outbound) string {
+	if o == nil {
+		return "<nil>"
+	}
+	return o.Tag()
+}
+
+// --- Close is final ---------------------------------------------------------
+
+// TestGroupCloseIsFinalForALaterTouch is the immortal-ticker regression.
+//
+// Close used to return early whenever no ticker happened to be armed — which is the
+// normal state of a group nobody is dialling — WITHOUT closing g.close. Nothing else
+// records that a group was shut down (started is never cleared), so a Touch arriving
+// afterwards armed a fresh ticker and a fresh loopCheck goroutine waiting on a channel
+// that would never be closed. Its only other exit, the idle timeout, does not fire for a
+// group the routing config reaches.
+//
+// A later Touch is not hypothetical: shater/engine/grouptest.go dials through outbounds
+// taken from a snapshot at the start of a run and keeps doing so for up to 120s, so
+// "press Test in the panel, then apply a config within two minutes" is enough. The
+// retired group then probes forever through a cancelled context — every probe fails
+// instantly — and files "dead" for its members on the SHARED health board that the LIVE
+// generation picks nodes from.
+func TestGroupCloseIsFinalForALaterTouch(t *testing.T) {
+	hist := urltest.NewHistoryStorage()
+	defer hist.Close()
+	var dialed []string
+	a := &healthNode{tag: "a", fail: true, dialed: &dialed}
+	g := healthTestGroup(hist, managerOf(a), a)
+	g.pause = pause.ManagerFromContext(pause.WithDefaultManager(context.Background()))
+	// Fast enough that a surviving ticker proves itself within the test's patience.
+	g.interval = 10 * time.Millisecond
+	g.idleTimeout = time.Hour
+	// Started, but idle: no ticker armed. This is the state Close mishandled.
+	g.started.Store(true)
+
+	if err := g.Close(); err != nil {
+		t.Fatalf("Close: %v", err)
+	}
+	g.Touch()
+
+	g.access.Lock()
+	ticker := g.ticker
+	g.access.Unlock()
+	if ticker != nil {
+		t.Fatal("Touch armed a probing ticker on a CLOSED group — nothing can stop it: " +
+			"its loopCheck waits on a channel that will never be closed")
+	}
+
+	// The consequence, stated in the terms that actually hurt: no probe, so no forged
+	// verdict on the shared board.
+	time.Sleep(150 * time.Millisecond)
+	if got := dialsOf(&dialed); len(got) != 0 {
+		t.Fatalf("a closed group dialled %v — a retired generation is writing to the live health board", got)
+	}
+	if v := hist.Verdict("a", 10*time.Minute); v != urltest.VerdictUntested {
+		t.Fatalf("verdict(a) = %v after closing the group, want untested — the dead marks are forged", v)
+	}
+}
+
+// TestGroupCloseStopsAnArmedTicker keeps the original behaviour honest: when a ticker IS
+// armed, Close still stops it, unregisters the pause callback and signals loopCheck.
+func TestGroupCloseStopsAnArmedTicker(t *testing.T) {
+	hist := urltest.NewHistoryStorage()
+	defer hist.Close()
+	a := &healthNode{tag: "a", fail: true}
+	g := healthTestGroup(hist, managerOf(a), a)
+	g.pause = pause.ManagerFromContext(pause.WithDefaultManager(context.Background()))
+	g.interval = 10 * time.Millisecond
+	g.idleTimeout = time.Hour
+	g.started.Store(true)
+	g.lastActive.Store(time.Now())
+
+	g.Touch()
+	g.access.Lock()
+	armed := g.ticker != nil
+	g.access.Unlock()
+	if !armed {
+		t.Fatal("Touch did not arm the ticker on a live group")
+	}
+
+	if err := g.Close(); err != nil {
+		t.Fatalf("Close: %v", err)
+	}
+	g.access.Lock()
+	stillArmed := g.ticker != nil
+	g.access.Unlock()
+	if stillArmed {
+		t.Fatal("Close left the ticker armed")
+	}
+	select {
+	case <-g.close:
+	default:
+		t.Fatal("Close did not signal loopCheck")
+	}
+	// Idempotent: a second Close must not close an already-closed channel (panic) or
+	// undo anything.
+	if err := g.Close(); err != nil {
+		t.Fatalf("second Close: %v", err)
+	}
+}
+
+// TestGroupPostStartAfterCloseDoesNothing: the other way a retired group can be woken.
+// PostStart is called on every member of a box at start-up; a group closed by a racing
+// shutdown must not be brought back by it.
+func TestGroupPostStartAfterCloseDoesNothing(t *testing.T) {
+	hist := urltest.NewHistoryStorage()
+	defer hist.Close()
+	var dialed []string
+	a := &healthNode{tag: "a", fail: true, dialed: &dialed}
+	g := healthTestGroup(hist, managerOf(a), a)
+	g.pause = pause.ManagerFromContext(pause.WithDefaultManager(context.Background()))
+	g.interval = 10 * time.Millisecond
+	g.idleTimeout = time.Hour
+
+	_ = g.Close()
+	g.PostStart()
+	time.Sleep(150 * time.Millisecond)
+
+	if g.started.Load() {
+		t.Fatal("PostStart marked a closed group as started")
+	}
+	if got := dialsOf(&dialed); len(got) != 0 {
+		t.Fatalf("PostStart on a closed group ran the warm-up sweep: dialled %v", got)
+	}
+}

protocol/group/urltest_selfcheck_lx_test.go

@@ -6,12 +6,14 @@ package group
 
 import (
 	"context"
+	"sync"
 	"testing"
 	"time"
 
 	"github.com/sagernet/sing-box/common/urltest"
 	"github.com/sagernet/sing-box/log"
 	"github.com/sagernet/sing-box/option"
+	"github.com/sagernet/sing/service/pause"
 )
 
 // waitForHistory polls until the store holds an entry for tag or the deadline
@@ -114,3 +116,157 @@ func TestSelfCheckOptionPlumbing(t *testing.T) {
 		t.Fatal("SelfCheck=false must stand the self-check down")
 	}
 }
+
+// lx: health board §5.C — the RUNTIME gate (urltest.ProbeGate). The self-check
+// flag above says "the config reaches nothing here"; the gate says "the path in
+// front of this group is down right now". Both stand the SCHEDULE down; neither
+// touches an explicit check; and only the gate is allowed to change its mind
+// while the box runs.
+
+// fakeGate answers from a mutable set of blocked tags, so one test can watch a
+// group stop dialling and start again without rebuilding anything.
+type fakeGate struct {
+	mu      sync.Mutex
+	blocked map[string]bool
+	warm    map[string]bool
+	asked   int
+}
+
+func (g *fakeGate) ProbeAllowed(tag string) bool {
+	g.mu.Lock()
+	defer g.mu.Unlock()
+	g.asked++
+	return !g.blocked[tag]
+}
+
+func (g *fakeGate) ProbeWhenIdle(tag string) bool {
+	g.mu.Lock()
+	defer g.mu.Unlock()
+	return g.warm[tag]
+}
+
+func (g *fakeGate) set(tag string, blocked bool) {
+	g.mu.Lock()
+	defer g.mu.Unlock()
+	g.blocked[tag] = blocked
+}
+
+func (g *fakeGate) asks() int {
+	g.mu.Lock()
+	defer g.mu.Unlock()
+	return g.asked
+}
+
+// A gated group makes NO DIAL ATTEMPT on its own schedule — the assertion is on
+// the attempt log, not on the board, because a probe that ran and failed leaves
+// the same "nothing useful known" as one that never ran, and only the attempt
+// log tells them apart. This is the waste half of the chain-hop fix: a hop
+// sitting behind a dead hop would otherwise spend one probe timeout per member
+// rediscovering the same broken hop.
+func TestProbeGateBlocksScheduledDials(t *testing.T) {
+	hist := urltest.NewHistoryStorage()
+	defer hist.Close()
+	var dialed []string
+	a := &healthNode{tag: "chain-c-h3-a", fail: true, dialed: &dialed}
+	b := &healthNode{tag: "chain-c-h3-b", fail: true, dialed: &dialed}
+	gate := &fakeGate{blocked: map[string]bool{"chain-c-h3": true}}
+
+	g := healthTestGroup(hist, managerOf(a, b), a, b)
+	g.tag = "chain-c-h3"
+	g.probeGate = gate
+	// Touch arms a real ticker, so this group needs the two things
+	// healthTestGroup leaves out because nothing else in that suite starts one:
+	// a pause manager to register the ticker with, and the close channel Close
+	// shuts the loop down through.
+	g.pause = pause.ManagerFromContext(pause.WithDefaultManager(context.Background()))
+	g.close = make(chan struct{})
+
+	// The warm-up sweep: gated, so nothing is dialled. Give the (non-existent)
+	// sweep real time to have happened — the absence is the assertion.
+	g.PostStart()
+	if waitForHistory(hist, "chain-c-h3-a", 150*time.Millisecond) {
+		t.Fatal("a gated group's PostStart wrote to the board")
+	}
+	// A ticker tick, driven directly: this is the exact call loopCheck makes.
+	g.scheduledCheck()
+	if got := dialsOf(&dialed); len(got) != 0 {
+		t.Fatalf("gated group dialled %v; a hop behind a dead hop must not dial at all", got)
+	}
+
+	// Touch still arms the ticker. Refusing to arm it would leave a recovered
+	// hop with nothing to notice — the block would outlive the failure.
+	g.Touch()
+	g.access.Lock()
+	ticker := g.ticker
+	g.access.Unlock()
+	if ticker == nil {
+		t.Fatal("Touch did not arm the ticker on a gated group; nothing would be left to spot the recovery")
+	}
+	_ = g.Close()
+
+	// The hop in front comes back. Nothing is reset, nothing is reapplied — the
+	// next scheduled check simply asks again and gets a different answer.
+	gate.set("chain-c-h3", false)
+	before := gate.asks()
+	g.scheduledCheck()
+	if gate.asks() <= before {
+		t.Error("scheduledCheck did not re-ask the gate; a cached answer is a block that outlives its cause")
+	}
+	if len(dialsOf(&dialed)) == 0 {
+		t.Fatal("the group did not resume dialling after the hop in front recovered")
+	}
+}
+
+// An EXPLICIT check is a deliberate request and is never gated — the same rule
+// SelfCheck already follows. The gate stands down the schedule, not the
+// capability.
+func TestProbeGateDoesNotBlockExplicitCheck(t *testing.T) {
+	hist := urltest.NewHistoryStorage()
+	defer hist.Close()
+	var dialed []string
+	a := &healthNode{tag: "chain-c-h3-a", fail: true, dialed: &dialed}
+	g := healthTestGroup(hist, managerOf(a), a)
+	g.tag = "chain-c-h3"
+	g.probeGate = &fakeGate{blocked: map[string]bool{"chain-c-h3": true}}
+
+	g.CheckOutbounds(true)
+	if len(dialsOf(&dialed)) == 0 {
+		t.Fatal("an explicit CheckOutbounds was refused by the gate")
+	}
+}
+
+// The two refusals are independent and compose the obvious way; and the absent
+// cases (no gate at all, an ungated tag) leave today's behaviour untouched,
+// which is what every plain sing-box config and every hand-built group relies
+// on.
+func TestSelfCheckAllowedCombinations(t *testing.T) {
+	hist := urltest.NewHistoryStorage()
+	defer hist.Close()
+	a := &healthNode{tag: "a"}
+	base := func() *URLTestGroup { return healthTestGroup(hist, managerOf(a), a) }
+
+	if g := base(); !g.selfCheckAllowed() {
+		t.Error("a plain group with no gate must probe (the zero value is the compatibility default)")
+	}
+	g := base()
+	g.selfCheckDisabled = true
+	g.tag, g.probeGate = "chain-c-h3", &fakeGate{blocked: map[string]bool{}}
+	if g.selfCheckAllowed() {
+		t.Error("an UNUSED group must stay down even when the path in front is fine")
+	}
+	g = base()
+	g.tag, g.probeGate = "chain-c-h3", &fakeGate{blocked: map[string]bool{"chain-c-h3": true}}
+	if g.selfCheckAllowed() {
+		t.Error("a group behind a dead hop must not run its schedule")
+	}
+	g = base()
+	g.tag, g.probeGate = "auto", &fakeGate{blocked: map[string]bool{"chain-c-h3": true}}
+	if !g.selfCheckAllowed() {
+		t.Error("an unrelated group was gated by another tag's block")
+	}
+	g = base()
+	g.probeGate = &fakeGate{blocked: map[string]bool{"": true}}
+	if !g.selfCheckAllowed() {
+		t.Error("a group with no tag must not be gated; there is nothing to ask about")
+	}
+}

protocol/wireguard/awg_over_wireguard_start_lx_test.go

@@ -0,0 +1,129 @@
+//go:build with_gvisor && with_awg
+
+// lx: regression for the removal of the AmneziaWG-over-WireGuard start guard.
+//
+// The guard refused to bring up an AmneziaWG endpoint whose detour chain reached
+// a WireGuard-based endpoint — and refused *silently*: Start returned nil with
+// started=false, so the endpoint looked configured but every dial through it
+// failed with "WireGuard is not ready yet". The root cause it protected against
+// (a kernel hang on Android) is gone on this graft (ClientBind reserved-gate),
+// and Android is not a supported platform here at all.
+//
+// This test builds a real AmneziaWG endpoint (junk + ranged magic headers) whose
+// detour points at an outbound of type "wireguard", drives both start stages,
+// and asserts the endpoint reports itself started. With the guard in place the
+// first stage short-circuits and started stays false — this test fails.
+package wireguard
+
+import (
+	"context"
+	"crypto/rand"
+	"encoding/base64"
+	"net"
+	"net/netip"
+	"os"
+	"testing"
+
+	"github.com/sagernet/sing-box/adapter"
+	C "github.com/sagernet/sing-box/constant"
+	"github.com/sagernet/sing-box/log"
+	"github.com/sagernet/sing-box/option"
+	"github.com/sagernet/sing/common/json/badoption"
+	M "github.com/sagernet/sing/common/metadata"
+	"github.com/sagernet/sing/service"
+	"github.com/sagernet/sing/service/pause"
+)
+
+// wgTypedOutbound is an adapter.Outbound that reports type "wireguard" — the hop
+// the guard used to refuse to start behind. Dialling through it always fails:
+// the point of the test is that the upper endpoint comes UP, not that it carries
+// traffic (that is the job of the transport-level e2e stand).
+type wgTypedOutbound struct {
+	adapter.Outbound
+	tag string
+}
+
+func (o *wgTypedOutbound) Type() string           { return C.TypeWireGuard }
+func (o *wgTypedOutbound) Tag() string            { return o.tag }
+func (o *wgTypedOutbound) Dependencies() []string { return nil }
+
+func (o *wgTypedOutbound) DialContext(ctx context.Context, network string, destination M.Socksaddr) (net.Conn, error) {
+	return nil, os.ErrClosed
+}
+
+func (o *wgTypedOutbound) ListenPacket(ctx context.Context, destination M.Socksaddr) (net.PacketConn, error) {
+	return nil, os.ErrClosed
+}
+
+// startChainManager resolves tags from a fixed map. adapter.OutboundManager is
+// embedded so this compiles against either shape of the interface.
+type startChainManager struct {
+	adapter.OutboundManager
+	byTag map[string]adapter.Outbound
+}
+
+func (m *startChainManager) Outbound(tag string) (adapter.Outbound, bool) {
+	ob, loaded := m.byTag[tag]
+	return ob, loaded
+}
+
+func randomKey(t *testing.T) string {
+	t.Helper()
+	var key [32]byte
+	if _, err := rand.Read(key[:]); err != nil {
+		t.Fatal(err)
+	}
+	// Clamp so wireguard-go accepts it as a curve25519 private key.
+	key[0] &= 248
+	key[31] = (key[31] & 127) | 64
+	return base64.StdEncoding.EncodeToString(key[:])
+}
+
+// TestAmneziaWGOverWireGuardDetourStarts pins the invariant: an AmneziaWG
+// endpoint detouring through a WireGuard hop must come up like any other.
+func TestAmneziaWGOverWireGuardDetourStarts(t *testing.T) {
+	ctx := pause.WithDefaultManager(context.Background())
+	ctx = service.ContextWith[adapter.OutboundManager](ctx, &startChainManager{
+		byTag: map[string]adapter.Outbound{
+			"wg-hop": &wgTypedOutbound{tag: "wg-hop"},
+		},
+	})
+	options := option.WireGuardEndpointOptions{
+		MTU:        1280,
+		Address:    badoption.Listable[netip.Prefix]{netip.MustParsePrefix("10.7.0.2/32")},
+		PrivateKey: randomKey(t),
+		Peers: []option.WireGuardPeer{{
+			Address:    "10.9.9.9",
+			Port:       51820,
+			PublicKey:  randomKey(t),
+			AllowedIPs: badoption.Listable[netip.Prefix]{netip.MustParsePrefix("0.0.0.0/0")},
+		}},
+		AmneziaWGOptions: option.AmneziaWGOptions{
+			Jc:   3,
+			Jmin: 8,
+			Jmax: 80,
+			S4:   16,
+			H1:   "10-20",
+			H2:   "30-40",
+			H3:   "50-60",
+			H4:   "70-80",
+		},
+	}
+	options.Detour = "wg-hop"
+
+	ep, err := NewEndpoint(ctx, nil, log.NewNOPFactory().NewLogger("wg-awg"), "wg-awg", options)
+	if err != nil {
+		t.Fatal("create amneziawg endpoint over a wireguard detour: ", err)
+	}
+	defer ep.Close()
+
+	if err = ep.Start(adapter.StartStateStart); err != nil {
+		t.Fatal("start stage: ", err)
+	}
+	if err = ep.Start(adapter.StartStatePostStart); err != nil {
+		t.Fatal("post-start stage: ", err)
+	}
+	if !ep.(*Endpoint).started.Load() {
+		t.Fatal("an amneziawg endpoint behind a wireguard hop must start; it is silently held down")
+	}
+}

protocol/wireguard/awg_start_guard_test.go

@@ -1,100 +0,0 @@
-// lx:begin awg
-
-package wireguard
-
-import (
-	"testing"
-
-	"github.com/sagernet/sing-box/adapter"
-	C "github.com/sagernet/sing-box/constant"
-)
-
-// fakeOutbound is a minimal adapter.Outbound for the start-guard chain walk:
-// only Type() and Dependencies() (the detour) are consulted. The embedded
-// interface is nil — any other method would panic, which never happens here.
-type fakeOutbound struct {
-	adapter.Outbound
-	tag         string
-	outboundTyp string
-	detour      string
-}
-
-func (o *fakeOutbound) Type() string { return o.outboundTyp }
-func (o *fakeOutbound) Tag() string  { return o.tag }
-func (o *fakeOutbound) Dependencies() []string {
-	if o.detour == "" {
-		return nil
-	}
-	return []string{o.detour}
-}
-
-// fakeGroup is an adapter.OutboundGroup (selector/urltest stand-in); the chain
-// walk must stop at it without expanding All().
-type fakeGroup struct {
-	fakeOutbound
-	members []string
-}
-
-func (g *fakeGroup) Now() string   { return "" }
-func (g *fakeGroup) All() []string { return g.members }
-
-type fakeOutboundManager struct {
-	adapter.OutboundManager
-	byTag map[string]adapter.Outbound
-}
-
-func (m *fakeOutboundManager) Outbound(tag string) (adapter.Outbound, bool) {
-	ob, loaded := m.byTag[tag]
-	return ob, loaded
-}
-
-func TestAwgDetourChainReachesWireGuard(t *testing.T) {
-	mgr := &fakeOutboundManager{byTag: map[string]adapter.Outbound{
-		// AWG -> wg-out (direct)
-		"wg-out": &fakeOutbound{tag: "wg-out", outboundTyp: C.TypeWireGuard},
-		// AWG -> vless-hop -> wg-deep (transitive)
-		"vless-hop": &fakeOutbound{tag: "vless-hop", outboundTyp: C.TypeVLESS, detour: "wg-deep"},
-		"wg-deep":   &fakeOutbound{tag: "wg-deep", outboundTyp: C.TypeWireGuard},
-		// AWG -> vless-leaf -> direct-leaf (no wireguard anywhere)
-		"vless-leaf":  &fakeOutbound{tag: "vless-leaf", outboundTyp: C.TypeVLESS, detour: "direct-leaf"},
-		"direct-leaf": &fakeOutbound{tag: "direct-leaf", outboundTyp: C.TypeDirect},
-		// AWG -> sel (selector hiding a wireguard member) — walk must stop, return ""
-		"sel": &fakeGroup{
-			fakeOutbound: fakeOutbound{tag: "sel", outboundTyp: C.TypeSelector},
-			members:      []string{"wg-out"},
-		},
-		// cyclic detour: a -> b -> a, no wireguard
-		"cyc-a": &fakeOutbound{tag: "cyc-a", outboundTyp: C.TypeVLESS, detour: "cyc-b"},
-		"cyc-b": &fakeOutbound{tag: "cyc-b", outboundTyp: C.TypeVLESS, detour: "cyc-a"},
-	}}
-
-	cases := []struct {
-		name      string
-		start     string
-		wantEmpty bool
-		wantTag   string
-	}{
-		{"direct wireguard", "wg-out", false, "wg-out"},
-		{"transitive via vless", "vless-hop", false, "wg-deep"},
-		{"no wireguard in chain", "vless-leaf", true, ""},
-		{"selector in the middle is skipped", "sel", true, ""},
-		{"cyclic chain terminates", "cyc-a", true, ""},
-		{"unknown tag", "nope", true, ""},
-	}
-	for _, tc := range cases {
-		t.Run(tc.name, func(t *testing.T) {
-			got := awgDetourChainReachesWireGuard(mgr, tc.start, make(map[string]bool))
-			if tc.wantEmpty {
-				if got != "" {
-					t.Fatalf("expected no wireguard in chain, got %q", got)
-				}
-				return
-			}
-			if got != tc.wantTag {
-				t.Fatalf("expected blocked-by %q, got %q", tc.wantTag, got)
-			}
-		})
-	}
-}
-
-// lx:end awg

protocol/wireguard/endpoint.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"net"
 	"net/netip"
-	"strconv"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -45,28 +44,14 @@ type Endpoint struct {
 	localAddresses []netip.Prefix
 	endpoint       *wireguard.Endpoint
 	started        atomic.Bool
-	// lx:begin awg
-	// awgActive marks this endpoint as running AmneziaWG (AmneziaWGOptions.IsSet());
-	// detour is its configured upstream tag. Start uses them to refuse to bring up
-	// an AmneziaWG-over-WireGuard chain, which hangs the kernel on Android — see
-	// awgDetourChainReachesWireGuard. The ledger lives here (not just in the dialer
-	// guard) because the hang happens synchronously in Start, before any dial.
-	awgActive bool
-	detour    string
-	// awgChainBlocked is set by Start when the AmneziaWG-over-WireGuard guard
-	// fires: the device is left unstarted (started stays false) so no junk
-	// handshake runs and the kernel cannot hang, while the rest of the instance
-	// comes up. PostStart then skips this endpoint too.
-	awgChainBlocked bool
-	// lx:end awg
 	// lx:begin idle-suspend
 	// SPEC 020 idle-suspend state. lastActivity is the unix-nano timestamp of the
 	// last dial through this endpoint, stamped at PostStart and on every dial entry.
 	// idleAsleep is true while the endpoint is Down due to idle-suspend (distinct
-	// from a guard-suspend, which sets started=false and clears idleAsleep, so a
-	// guard-suspended endpoint fast-paths out of resumeOnDial and is never
-	// idle-woken). resumeMu serialises the idle tick's suspend decision, a dial's
-	// wake, and the AmneziaWG guard-suspend against one another.
+	// from a deliberately-stopped endpoint, which has started=false and
+	// idleAsleep=false, so it fast-paths out of resumeOnDial and is never
+	// idle-woken). resumeMu serialises the idle tick's suspend decision against a
+	// dial's wake.
 	lastActivity atomic.Int64
 	idleAsleep   atomic.Bool
 	resumeMu     sync.Mutex
@@ -74,6 +59,16 @@ type Endpoint struct {
 }
 
 func NewEndpoint(ctx context.Context, router adapter.Router, logger log.ContextLogger, tag string, options option.WireGuardEndpointOptions) (adapter.Endpoint, error) {
+	// lx: allow OS-level fragmentation of the OUTER UDP socket by default, the
+	// same opt-out direct/hysteria/hysteria2/tuic already take. Without it the
+	// dialer sets DF (IP_MTU_DISCOVER=IP_PMTUDISC_DO on linux), and an outer
+	// datagram over the path MTU — routine once anything is encapsulated: WG's
+	// own ~32 B header, AmneziaWG s4 transport junk, or this endpoint carrying a
+	// nested tunnel — is dropped by the kernel ("message too long") instead of
+	// fragmented, so the tunnel comes up and then carries nothing. An explicit
+	// `udp_fragment: false` on the node still restores DF (UDPFragment wins over
+	// UDPFragmentDefault in common/dialer).
+	options.UDPFragmentDefault = true
 	ep := &Endpoint{
 		Adapter:        endpoint.NewAdapterWithDialerOptions(C.TypeWireGuard, tag, []string{N.NetworkTCP, N.NetworkUDP, N.NetworkICMP}, options.DialerOptions),
 		ctx:            ctx,
@@ -81,10 +76,6 @@ func NewEndpoint(ctx context.Context, router adapter.Router, logger log.ContextL
 		dnsRouter:      service.FromContext[adapter.DNSRouter](ctx),
 		logger:         logger,
 		localAddresses: options.Address,
-		// lx:begin awg
-		awgActive: options.AmneziaWGOptions.IsSet(),
-		detour:    options.Detour,
-		// lx:end awg
 	}
 	if options.Detour != "" && options.ListenPort != 0 {
 		return nil, E.New("`listen_port` is conflict with `detour`")
@@ -117,6 +108,7 @@ func NewEndpoint(ctx context.Context, router adapter.Router, logger log.ContextL
 		CreateDialer: func(interfaceName string) N.Dialer {
 			return common.Must1(dialer.NewDefault(ctx, option.DialerOptions{
 				BindInterface:      interfaceName,
+				UDPFragmentDefault: true, // lx: same reason as above — this is the bind-to-interface twin of the outer socket
 			}))
 		},
 		Name:       options.Name,
@@ -157,33 +149,6 @@ func NewEndpoint(ctx context.Context, router adapter.Router, logger log.ContextL
 }
 
 func (w *Endpoint) Start(stage adapter.StartStage) error {
-	// lx:begin awg
-	// Refuse to bring up an AmneziaWG endpoint whose detour chain reaches a
-	// WireGuard-based endpoint: encapsulating AWG (junk handshake) inside a
-	// WireGuard tunnel hangs the kernel on Android. The hang happens here, in the
-	// synchronous Start path (peer-domain resolution over the detour, then the
-	// device's junk handshake) — before any dial — so the lazy DetourDialer guard
-	// never gets a chance to fire. We must catch it at Start instead.
-	//
-	// Behaviour is "variant B": do NOT return an error (that would abort the whole
-	// instance start). Instead log, skip device startup, and leave started=false
-	// so the rest of the config comes up and every dial through this endpoint
-	// fails cleanly with "WireGuard is not ready yet". A selector/urltest in the
-	// middle hides the real target at start time, so the chain walk stops at a
-	// group and that case is left to the lazy DetourDialer guard at dial time.
-	if stage == adapter.StartStateStart && w.awgActive && w.detour != "" {
-		if outboundManager := service.FromContext[adapter.OutboundManager](w.ctx); outboundManager != nil {
-			if blockedBy := awgDetourChainReachesWireGuard(outboundManager, w.detour, make(map[string]bool)); blockedBy != "" {
-				w.awgChainBlocked = true
-				w.logger.Error("amneziawg endpoint will not start: its detour chain reaches wireguard-based endpoint ", strconv.Quote(blockedBy), " — amneziawg over wireguard is not supported. Use a non-wireguard detour (e.g. vless).")
-				return nil
-			}
-		}
-	}
-	if w.awgChainBlocked {
-		return nil
-	}
-	// lx:end awg
 	switch stage {
 	case adapter.StartStateStart:
 		return w.endpoint.Start(false)
@@ -200,69 +165,6 @@ func (w *Endpoint) Start(stage adapter.StartStage) error {
 	return nil
 }
 
-// lx:begin awg
-// awgDetourChainReachesWireGuard walks the transitive detour chain starting at
-// tag and returns the tag of the first WireGuard-based outbound it reaches
-// (type "wireguard", covering plain WireGuard and AmneziaWG), or "" if none. It
-// follows each outbound's detour dependency; it deliberately does NOT expand
-// selector/urltest groups, whose chosen member is only known at runtime — that
-// case is handled lazily by the DetourDialer guard. visited guards against cyclic
-// detour configs. All outbounds are registered before any Start, so every tag in
-// the chain is resolvable here even though some may not have started yet.
-func awgDetourChainReachesWireGuard(outboundManager adapter.OutboundManager, tag string, visited map[string]bool) string {
-	if tag == "" || visited[tag] {
-		return ""
-	}
-	visited[tag] = true
-	outbound, loaded := outboundManager.Outbound(tag)
-	if !loaded {
-		return ""
-	}
-	if outbound.Type() == C.TypeWireGuard {
-		return tag
-	}
-	if _, isGroup := outbound.(adapter.OutboundGroup); isGroup {
-		// Runtime-resolved target — leave it to the lazy DetourDialer guard.
-		return ""
-	}
-	for _, dependency := range outbound.Dependencies() {
-		if blockedBy := awgDetourChainReachesWireGuard(outboundManager, dependency, visited); blockedBy != "" {
-			return blockedBy
-		}
-	}
-	return ""
-}
-
-// IsAmneziaWG reports whether this endpoint runs AmneziaWG. Implements
-// adapter.AmneziaWGSuspendable.
-func (w *Endpoint) IsAmneziaWG() bool {
-	return w.awgActive
-}
-
-// SuspendAmneziaWG brings the device down and marks the endpoint not-ready, so a
-// junk handshake is never sent and every dial fails with "WireGuard is not ready
-// yet". Called by the selector guard when a group this endpoint detours through
-// switches to a WireGuard member (AmneziaWG over WireGuard hangs the kernel on
-// Android). Idempotent. Implements adapter.AmneziaWGSuspendable.
-func (w *Endpoint) SuspendAmneziaWG() {
-	// Take resumeMu so this is ordered against resumeOnDial/SuspendIfIdle: without
-	// it, a dial that already passed resumeOnDial's idleAsleep checks could wake
-	// the endpoint back up right after we clear the flag, defeating the guard.
-	w.resumeMu.Lock()
-	defer w.resumeMu.Unlock()
-	if w.started.CompareAndSwap(true, false) {
-		w.logger.Error("amneziawg endpoint suspended: a selector in its detour chain switched to a wireguard-based member — amneziawg over wireguard is not supported")
-	}
-	// Clear any idle-suspend state so resumeOnDial does not resurrect a
-	// guard-suspended endpoint: if it was idle-asleep first, idleAsleep would still
-	// be true and the next dial would wake it (SPEC 022 #2). With idleAsleep=false
-	// resumeOnDial's fast path returns started (now false) and the endpoint stays down.
-	w.idleAsleep.Store(false)
-	w.endpoint.Suspend()
-}
-
-// lx:end awg
-
 // lx:begin idle-suspend
 
 // stampActivity records the current time as the last dial through this endpoint.
@@ -286,8 +188,8 @@ func (w *Endpoint) IdleSince() time.Duration {
 // holder — when it is unreachable from the active routing tree AND has been idle
 // past the threshold. Silent on every non-transition (edge-triggered logging).
 //
-// It never touches a guard-suspended endpoint: that one already has
-// started==false but idleAsleep==false, and the `!started` guard below short-
+// It never touches a deliberately-stopped endpoint: that one already has
+// started==false but idleAsleep==false, and the `!started` check below short-
 // circuits before the CAS. resumeMu mutually excludes this against resumeOnDial.
 func (w *Endpoint) SuspendIfIdle(reachable bool, threshold time.Duration) {
 	w.resumeMu.Lock()
@@ -296,7 +198,7 @@ func (w *Endpoint) SuspendIfIdle(reachable bool, threshold time.Duration) {
 		return
 	}
 	if !w.started.Load() {
-		// Already down some other way (guard-suspend, awg-chain-blocked, closed).
+		// Already down some other way (deliberately stopped, closed).
 		return
 	}
 	if w.idleAsleep.CompareAndSwap(false, true) {
@@ -313,7 +215,7 @@ func (w *Endpoint) SuspendIfIdle(reachable bool, threshold time.Duration) {
 // session); that cost is on the first packet, as for any cold WG dial.
 //
 // Returns true if the endpoint is dialable (awake), false if it must stay down
-// (guard-suspend / chain-blocked — not an idle-suspend, so we do not resurrect it).
+// (deliberately stopped / closed — not an idle-suspend, so we do not resurrect it).
 func (w *Endpoint) resumeOnDial() bool {
 	w.stampActivity()
 	if !w.idleAsleep.Load() {

protocol/wireguard/endpoint_idle_lx_test.go

@@ -103,21 +103,21 @@ func TestSuspendIfIdle_idempotentCAS(t *testing.T) {
 	}
 }
 
-// TestSuspendIfIdle_guardSuspendedNotTouched is the §8 invariant verified live on
-// an AWG-over-WG endpoint (wg-3 in the prod run): a guard-suspended endpoint has
-// started=false WITHOUT idleAsleep. The idle tick must early-return on !started and
-// NOT flip idleAsleep — otherwise a later resumeOnDial would idle-wake it and
-// re-trigger the AWG-over-WG kernel hang the guard exists to prevent.
-func TestSuspendIfIdle_guardSuspendedNotTouched(t *testing.T) {
+// TestSuspendIfIdle_stoppedNotTouched is the §8 invariant: a deliberately-stopped
+// endpoint (Close, or a start that never completed) has started=false WITHOUT
+// idleAsleep. The idle tick must early-return on !started and NOT flip idleAsleep
+// — otherwise a later resumeOnDial would idle-wake a device that was
+// intentionally down.
+func TestSuspendIfIdle_stoppedNotTouched(t *testing.T) {
 	w := newIdleTestEndpoint()
-	w.started.Store(false) // guard-suspend (device.Down at Start), idleAsleep stays false
+	w.started.Store(false) // stopped, idleAsleep stays false
 	w.lastActivity.Store(time.Now().Add(-time.Hour).UnixNano())
 	w.SuspendIfIdle(false, 30*time.Second)
 	if w.idleAsleep.Load() {
-		t.Fatal("a guard-suspended endpoint must NOT be flagged idleAsleep by the tick")
+		t.Fatal("a stopped endpoint must NOT be flagged idleAsleep by the tick")
 	}
 	if w.started.Load() {
-		t.Fatal("the tick must not change started for a guard-suspended endpoint")
+		t.Fatal("the tick must not change started for a stopped endpoint")
 	}
 }
 
@@ -152,17 +152,17 @@ func TestResumeOnDial_dialBeforeTickRace(t *testing.T) {
 	}
 }
 
-func TestResumeOnDial_guardSuspendedNotWoken(t *testing.T) {
-	// A guard-suspended endpoint has started=false but idleAsleep=false.
-	// resumeOnDial must NOT wake it (returns started, i.e. false).
+func TestResumeOnDial_stoppedNotWoken(t *testing.T) {
+	// A deliberately-stopped endpoint (Close / failed start) has started=false but
+	// idleAsleep=false. resumeOnDial must NOT wake it (returns started, i.e. false).
 	w := newIdleTestEndpoint()
-	w.started.Store(false) // simulate guard/awg-chain suspend (not idle)
+	w.started.Store(false) // stopped, not idle-suspended
 	ok := w.resumeOnDial()
 	if ok {
-		t.Fatal("resumeOnDial must not resurrect a guard-suspended (non-idle) endpoint")
+		t.Fatal("resumeOnDial must not resurrect a stopped (non-idle) endpoint")
 	}
 	if w.idleAsleep.Load() {
-		t.Fatal("guard-suspended endpoint must not be flagged idleAsleep")
+		t.Fatal("stopped endpoint must not be flagged idleAsleep")
 	}
 }
 

scripts/run-panel-tests.sh

@@ -0,0 +1,88 @@
+#!/usr/bin/env bash
+#
+# run-panel-tests.sh — the admin-panel half of the release test gate.
+#
+# panel/package.json has declared a `test` script since the SPA was scaffolded
+# and nothing had ever called it: not release.yml, not build-shaterd.sh (which
+# only runs `npm ci` + `npm run build`). This script is what CI calls, and it
+# does the one thing `npm test` alone cannot: prove that tests actually RAN.
+#
+#   `node --test src/*.test.ts` with no matching file leaves the glob unexpanded;
+#   node then reports `pass 0` and exits 0 — a green CI step that ran nothing,
+#   which is the exact failure class this whole change is about. So: the test
+#   files are counted BEFORE the run (a rename to *.spec.ts is named as such
+#   rather than showing up as a mystery), and the pass count is asserted > 0 and
+#   the fail count 0 after it.
+#
+#   KNOWN LIMIT: node --test counts a *.test.ts file that declares no cases at
+#   all as one passing "test" (the module loaded). So an emptied-out file still
+#   reads as pass 1 here. Deleting, renaming or breaking the file is caught;
+#   gutting its contents while keeping the name is not.
+#
+# NODE VERSION: >= 22.6. The tests are TypeScript executed directly by
+# `node --test`; type stripping does not exist before then, so on node 20 the
+# run dies with a syntax error. CI pins node 24 for this step (the SPA *build*
+# still uses node 20 — that one goes through vite/tsc and does not care).
+#
+# Usage: scripts/run-panel-tests.sh
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+REPO="$(cd "$SCRIPT_DIR/.." && pwd)"
+cd "$REPO/panel"
+
+node_major="$(node -p 'process.versions.node.split(".")[0]')"
+node_minor="$(node -p 'process.versions.node.split(".")[1]')"
+if [ "$node_major" -lt 22 ] || { [ "$node_major" -eq 22 ] && [ "$node_minor" -lt 6 ]; }; then
+	echo "  ERROR: panel tests are TypeScript under \`node --test\` and need node >= 22.6" >&2
+	echo "         (got $(node --version)). Type stripping does not exist before that." >&2
+	exit 1
+fi
+
+# The glob `npm test` itself uses. Counted here so "somebody renamed the tests"
+# is reported as that, instead of as a suspiciously fast green step.
+shopt -s nullglob
+files=(src/*.test.ts)
+shopt -u nullglob
+if [ "${#files[@]}" -eq 0 ]; then
+	echo "  ERROR: no panel/src/*.test.ts — panel/package.json's \`test\` script" >&2
+	echo "         would match nothing and still exit 0. Fix the glob or the files." >&2
+	exit 1
+fi
+
+echo "== panel tests (node $(node --version)), ${#files[@]} file(s) =="
+if [ ! -d node_modules ]; then
+	npm ci
+fi
+
+out=""
+rc=0
+set +e
+out="$(npm test --silent 2>&1)"
+rc=$?
+set -e
+sed 's/^/    /' <<<"$out"
+
+if [ "$rc" -ne 0 ]; then
+	echo "  FAILED: npm test exited $rc" >&2
+	exit 1
+fi
+
+# node --test's summary is `ℹ pass N` (spec reporter) or `# pass N` (tap).
+passed="$(sed -n 's/.*[[:space:]]pass[[:space:]]\{1,\}\([0-9]\{1,\}\).*/\1/p' <<<"$out" | tail -1)"
+failed="$(sed -n 's/.*[[:space:]]fail[[:space:]]\{1,\}\([0-9]\{1,\}\).*/\1/p' <<<"$out" | tail -1)"
+if [ -z "$passed" ]; then
+	echo "  FAILED: could not find a pass count in node --test output — the gate" >&2
+	echo "          cannot tell a green run from an empty one." >&2
+	exit 1
+fi
+if [ "$passed" -lt 1 ]; then
+	echo "  FAILED: 0 panel tests ran. \`npm test\` returned success having done nothing." >&2
+	exit 1
+fi
+if [ -n "$failed" ] && [ "$failed" -gt 0 ]; then
+	echo "  FAILED: $failed panel test(s) failed." >&2
+	exit 1
+fi
+
+echo "  OK: $passed panel test(s) passed."

scripts/run-tests.sh

@@ -0,0 +1,249 @@
+#!/usr/bin/env bash
+#
+# run-tests.sh — THE test gate of the release tract.
+#
+# WHY THIS EXISTS (2026-07-26)
+#   Until now the release tract ran almost no tests. The only `go test` calls in
+#   the whole publishing path were scripts/build-shaterd.sh's one-package
+#   buildtags check and the three named tests scripts/check-router-tags.sh runs.
+#   The upstream .github/workflows/test.yml triggers on `stable`/`testing`/
+#   `unstable` — branches this fork does not have — and Gitea does not read
+#   .github/workflows at all once .gitea/workflows exists. Net effect: 115 of the
+#   116 test files under shater/** had never executed in CI, and
+#   TestDNSFilterRemoteBlocklistHTTPClient shipped red through two releases
+#   before anyone ran it by hand.
+#
+# WHAT IT GUARANTEES
+#   1. The suite runs under the SHIPPED build tags (scripts/router-tags.sh), not
+#      under some CI-local tag set. This is not cosmetic: the AmneziaWG tests in
+#      transport/wireguard are `//go:build with_awg` — 1 test file compiles
+#      without the tag set, 7 with it. The 2026-07-25 WireGuard outage was
+#      exactly a "built with X, verified with Y" gap.
+#   2. It runs on linux. shater/generate has 44 test files on linux against 32 on
+#      windows/darwin; the linux-only half is where the routing, ruleset, DNS and
+#      health tests live.
+#   3. Nothing is skipped SILENTLY. Two machine checks:
+#        - the tag set may only ADD test files, never hide them (a test behind
+#          `//go:build !with_awg` would vanish from the gate — this fails first);
+#        - every package that has tests must report `ok` by name; a suite that
+#          compiles down to "no test files" fails the gate instead of passing it.
+#      A guard that silently runs nothing is worse than no guard (same rule as
+#      scripts/check-router-tags.sh).
+#
+# Usage:
+#   scripts/run-tests.sh            # full gate (~3 min warm on the runner)
+#   scripts/run-tests.sh --no-race  # skip the -race pass (faster; local loop)
+#
+# Env:
+#   SHATER_GO_IMAGE      docker image used to reach linux from a non-linux host
+#                        (default golang:1.26 — keep it >= go.mod's toolchain).
+#   SHATER_NO_DOCKER=1   fail instead of falling back to docker.
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+REPO="$(cd "$SCRIPT_DIR/.." && pwd)"
+cd "$REPO"
+
+RACE=1
+for a in "$@"; do
+	case "$a" in
+		--no-race) RACE=0 ;;
+		-h|--help) sed -n '2,41p' "$0" | sed 's/^# \{0,1\}//'; exit 0 ;;
+		*) echo "run-tests: unknown flag: $a" >&2; exit 2 ;;
+	esac
+done
+
+# shellcheck source=router-tags.sh
+. "$SCRIPT_DIR/router-tags.sh"
+
+# The fork's own trees plus the upstream trees the fork edits (adapter/, route/,
+# option/, dns/ all carry shater changes). ROOTS, not a hand-kept package list: a
+# new package with tests joins the gate the moment it is created, which is the
+# whole point.
+ROOTS=(./shater/... ./protocol/... ./transport/... ./adapter/... ./route/... ./option/... ./dns/...)
+
+# common/ is mostly upstream, but common/tls, common/tlsfragment, common/sniff
+# and common/urltest carry fork behaviour (D13 DPI-bypass, urltest health), so it
+# is in — minus the privileged integration tests below.
+ROOTS_COMMON=(./common/...)
+#   SKIP, WITH REASON: common/tlsspoof's TestIntegration* enter TCP_REPAIR and
+#   need CAP_NET_ADMIN. The act_runner job container runs as root but WITHOUT
+#   that capability, so they do not skip — they FAIL. Excluded by name so the
+#   rest of common/ can be a real gate instead of a permanently red one. (On
+#   linux every tlsspoof test is a TestIntegration*, so that package is
+#   effectively uncovered here; it is covered by the VM runs.)
+SKIP_COMMON='^TestIntegration'
+
+#   SKIP, WITH REASON: the first -race run over this tree (2026-07-26 — nobody
+#   had ever run one) turned up two failures. One was a REAL product race:
+#   ClientBind.connect() touched its fields from both the Send() path and
+#   RoutineReceiveIncoming() with no lock, caught by
+#   transport/wireguard.TestAwgDetourClientBindDelivers; that one has since been
+#   fixed in client_bind.go and is NOT skipped — it is exactly what this pass is
+#   for. What is left:
+#     - shater/alert.TestExpiryDedupWithinDay — the test's own closure
+#       (expiry_test.go:78) reads a variable the test body writes at :85 while
+#       Notifier.dispatch's goroutine is still delivering. A test-side bug, ~one
+#       mutex to fix, but it lives in shater/ and is nobody's blocker to ship.
+#   Naming it here keeps the gate a gate from day one. It is skipped ONLY in the
+#   -race pass — it still runs, and still has to pass, in the main pass below.
+#   DELETE THE ENTRY THE MOMENT THE RACE IS FIXED.
+RACE_SKIP='^TestExpiryDedupWithinDay$'
+
+echo "== shater test gate =="
+echo "  tags   : $SHATER_ROUTER_TAGS"
+echo "  ldflags: $SHATER_ROUTER_LDFLAGS"
+echo "  race   : $([ "$RACE" -eq 1 ] && echo yes || echo no)"
+echo
+
+# --- linux, or re-exec on linux ---------------------------------------------
+# The linux-only half of the suite is the half worth running (see header). From a
+# non-linux host, re-exec inside a golang container rather than quietly testing
+# 32 of shater/generate's 44 files — a partial gate reads exactly like a passing
+# one.
+if [ "$(go env GOOS)" != "linux" ] && [ "${SHATER_TESTS_IN_DOCKER:-0}" != "1" ]; then
+	if [ "${SHATER_NO_DOCKER:-0}" = "1" ] || ! command -v docker >/dev/null 2>&1; then
+		echo "  ERROR: the gate needs linux (GOOS=$(go env GOOS)) and docker is unavailable/disabled." >&2
+		echo "         Run it on the linux CI runner or the OpenWrt VM." >&2
+		exit 1
+	fi
+	image="${SHATER_GO_IMAGE:-golang:1.26}"
+	echo "== re-exec on linux via docker ($image) =="
+	host_repo="$REPO"
+	command -v cygpath >/dev/null 2>&1 && host_repo="$(cygpath -w "$REPO")"
+	MSYS2_ARG_CONV_EXCL='*' MSYS_NO_PATHCONV=1 docker run --rm \
+		-v "$host_repo":/src \
+		-v shater-tagcheck-gomod:/go/pkg/mod \
+		-v shater-tagcheck-gocache:/root/.cache/go-build \
+		-w /src \
+		-e SHATER_TESTS_IN_DOCKER=1 \
+		"$image" bash scripts/run-tests.sh "$@"
+	exit $?
+fi
+
+ALL_ROOTS=("${ROOTS[@]}" "${ROOTS_COMMON[@]}")
+
+# --- [1/4] the tag set may only ADD test files, never hide them --------------
+# `go list` counts the test files the compiler would actually take. If adding the
+# shipped tags REMOVES a test file from any package, that test exists but the
+# gate would never see it — which is the failure mode this whole script is about,
+# just pointed the other way.
+echo "== [1/4] no test file is hidden by the shipped tag set =="
+LISTFMT='{{.ImportPath}} {{len .TestGoFiles}} {{len .XTestGoFiles}}'
+plain="$(go list -f "$LISTFMT" "${ALL_ROOTS[@]}")"
+tagged="$(go list -tags "$SHATER_ROUTER_TAGS" -f "$LISTFMT" "${ALL_ROOTS[@]}")"
+hidden=0
+while read -r pkg t x; do
+	[ -n "${pkg:-}" ] || continue
+	n_plain=$((t + x))
+	[ "$n_plain" -gt 0 ] || continue
+	line="$(awk -v p="$pkg" '$1 == p { print; exit }' <<<"$tagged")"
+	if [ -z "$line" ]; then
+		echo "  HIDDEN: $pkg has $n_plain test file(s) untagged but no package at all under the shipped tags" >&2
+		hidden=1
+		continue
+	fi
+	read -r _ tt tx <<<"$line"
+	n_tagged=$((tt + tx))
+	if [ "$n_tagged" -lt "$n_plain" ]; then
+		echo "  HIDDEN: $pkg — $n_plain test file(s) untagged, only $n_tagged under the shipped tags" >&2
+		hidden=1
+	elif [ "$n_tagged" -gt "$n_plain" ]; then
+		echo "  +$((n_tagged - n_plain)) tag-gated test file(s): $pkg ($n_plain -> $n_tagged)"
+	fi
+done <<<"$plain"
+if [ "$hidden" -ne 0 ]; then
+	echo >&2
+	echo "  FAILED: a test file is invisible to the tag set we ship. Either the" >&2
+	echo "          constraint is wrong or the tag set is — do not paper over it" >&2
+	echo "          by testing with different tags than we build with." >&2
+	exit 1
+fi
+echo
+
+# --- the runner --------------------------------------------------------------
+# Runs one suite and then PROVES it ran: every package `go list` says has tests
+# must appear as `ok <pkg>` in the output. `go test` over a package whose tests
+# all vanished behind a build constraint prints "[no test files]" and exits 0 —
+# a green run that verified nothing.
+LOG="$(mktemp)"
+trap 'rm -f "$LOG"' EXIT
+FAILED=0
+
+run_suite() { # $1=label  $2=extra go-test flags (may be empty)  $3..=packages
+	local label="$1" extra="$2"
+	shift 2
+	local pkgs=("$@") rc=0 expect missing=0 pkg
+
+	expect="$(go list -tags "$SHATER_ROUTER_TAGS" \
+		-f '{{if or .TestGoFiles .XTestGoFiles}}{{.ImportPath}}{{end}}' \
+		"${pkgs[@]}" | grep -v '^$' || true)"
+	if [ -z "$expect" ]; then
+		echo "  FAILED [$label]: go list reports no package with tests here — the gate" >&2
+		echo "          would have run nothing and passed." >&2
+		FAILED=1
+		return
+	fi
+	echo "  packages with tests: $(wc -l <<<"$expect" | tr -d ' ')"
+
+	set +e
+	# shellcheck disable=SC2086  # $extra is a deliberate word-split flag list
+	go test -count=1 $extra \
+		-tags "$SHATER_ROUTER_TAGS" -ldflags "$SHATER_ROUTER_LDFLAGS" \
+		"${pkgs[@]}" >"$LOG" 2>&1
+	rc=$?
+	set -e
+	sed 's/^/    /' "$LOG"
+
+	if [ "$rc" -ne 0 ]; then
+		echo "  FAILED [$label]: go test exited $rc" >&2
+		FAILED=1
+		return
+	fi
+
+	while read -r pkg; do
+		[ -n "$pkg" ] || continue
+		grep -qE "^ok[[:space:]]+$pkg([[:space:]]|\$)" "$LOG" || {
+			echo "  DID NOT RUN [$label]: $pkg" >&2
+			missing=1
+		}
+	done <<<"$expect"
+	if [ "$missing" -ne 0 ]; then
+		echo "  FAILED [$label]: package(s) above have test files but produced no 'ok'" >&2
+		echo "          line. Build-constraint or file-name drift emptied them." >&2
+		FAILED=1
+		return
+	fi
+	echo "  OK [$label]"
+}
+
+# --- [2/4] the fork's trees, shipped tags, linux -----------------------------
+echo "== [2/4] go test — the fork's trees (shipped tags, linux) =="
+run_suite main "" "${ROOTS[@]}"
+echo
+
+# --- [3/4] common/, minus the tests that need CAP_NET_ADMIN ------------------
+echo "== [3/4] go test — common/ (minus the CAP_NET_ADMIN integration tests) =="
+run_suite common "-skip $SKIP_COMMON" "${ROOTS_COMMON[@]}"
+echo
+
+# --- [4/4] -race over the same trees -----------------------------------------
+# Everything, not a subset: shater/netplane alone is ~110 s under -race and it is
+# the single most concurrency-critical package we own (the nft data plane), so
+# once it is in, adding the rest costs ~40 s more. common/ is left out — it is
+# upstream code exercised by upstream CI.
+if [ "$RACE" -eq 1 ]; then
+	echo "== [4/4] go test -race — the fork's trees =="
+	echo "  known-red under -race, skipped BY NAME (fix it and delete from RACE_SKIP):"
+	echo "    TestExpiryDedupWithinDay   shater/alert   (test-side race, expiry_test.go:78/85)"
+	run_suite race "-race -skip $RACE_SKIP" "${ROOTS[@]}"
+else
+	echo "== [4/4] -race pass skipped (--no-race) =="
+fi
+echo
+
+if [ "$FAILED" -ne 0 ]; then
+	echo "== TEST GATE FAILED — nothing may be published from this run. ==" >&2
+	exit 1
+fi
+echo "== OK: the shipped tag set, on linux, passes every test we own. =="

shater/apply/apply.go

@@ -418,7 +418,7 @@ func (a *Applier) applyLocked(m *model.Model) (bool, error) {
 
 	// (2) engine swap. On error the old engine keeps running and we do NOT touch
 	// netplane — abort and surface the error.
-	changed, err := a.eng.Apply(opts)
+	changed, err := engineApply(a, opts)
 	if err != nil {
 		// ...unless the engine is not running AT ALL. A failed apply that left the
 		// PREVIOUS engine running still has a valid, loaded data plane — replacing
@@ -434,99 +434,19 @@ func (a *Applier) applyLocked(m *model.Model) (bool, error) {
 
 	// (3) netplane, fail-closed: on any failure return the error WITHOUT tearing
 	// the engine/table down (kill-switch/table stay up; the watchdog decides).
-	//
-	// Render FIRST, then decide whether anything needs re-asserting. Gating the
-	// whole data plane on the engine's `changed` flag alone was wrong: the engine
-	// hash covers option.Options only, so a purely netplane-visible change (the
-	// kill-switch flipping open->closed, DNS force-intercept, a rule gaining an
-	// iface:/zone: source, an inbound device rename) hashed identical, took the
-	// fast-path, and left the OLD ruleset loaded while the panel reported success.
-	// A stale-but-loaded fail-open table is exactly the leak this audit is about.
-	// Resolve WHERE the untunnelable-protocol drop applies before rendering. The
-	// engine is already running by this point (step 2), so its loaded rule-sets can
-	// supply the addresses a geoip list contributes; a stopped engine or a list that
-	// has not downloaded yet yields no plan and the conservative blanket drop.
-	//
-	// The resolved addresses are rendered INTO the ruleset text, so the idempotence
-	// check below sees them: a refreshed geoip list changes the text and triggers a
-	// real reload, rather than leaving a stale plan loaded (the D3 trap).
-	untunPlan := a.untunnelablePlanFor(m, opts)
-	ruleset, nftWarnings, err := netplane.RenderNftPlanAt(m, untunPlan, now)
-	if err != nil {
-		// Includes the refusal on an unusable interface name with a closed
-		// kill-switch: the previous ruleset stays loaded and keeps protecting the
-		// LAN while the operator fixes the name.
-		return changed, err
-	}
-	nftCurrent := ruleset == a.lastNft && netplane.TableExists()
-	if !nftCurrent {
-		if err := netplane.ApplyNft(ruleset); err != nil {
-			// The engine may be up, but with no table loaded nothing is diverted into
-			// it — LAN traffic goes straight out the WAN. That is the same silent
-			// fail-open as a dead engine, so it gets the same answer: if there is no
-			// table at all, hold the line rather than leave the LAN exposed.
-			if !netplane.TableExists() {
-				a.holdLocked(m, err)
-			}
-			return changed, err
-		}
-		a.lastNft = ruleset
-	}
-	// ApplyRouting is idempotent by del-then-add, which means it opens a brief
-	// window with NO fwmark rule installed — during it, diverted packets miss the
-	// `local default dev lo` table. Harmless on a real change (the plane is being
-	// rebuilt anyway), but pointless churn on a no-op reconcile, so skip it when
-	// the ruleset is unchanged AND the rule is verifiably still installed.
-	// routeWarnings carries an egress that was BUILT but cannot route (no nexthop on a
-	// non-point-to-point device). It is deliberately part of the status warning set:
-	// such an egress looks applied everywhere in the UI while being unable to reach
-	// anything off its own subnet. On the fast path nothing was rebuilt, so there is
-	// nothing new to report and the previous set stands.
-	var routeWarnings []string
-	if !nftCurrent || !netplane.RoutingPresent(m.Globals) {
-		var rerr error
-		routeWarnings, rerr = netplane.ApplyRoutingWithWarnings(m)
-		if rerr != nil {
-			return changed, rerr
-		}
-	}
-	if err := netplane.ApplySysctl(); err != nil {
-		return changed, err
-	}
-	// Per-diverted-ingress-iface knobs (accept_local/rp_filter): the static
-	// ApplySysctl above cannot know the LAN device names, and without
-	// accept_local=1 on the ingress iface the tproxied packet never reaches the
-	// engine socket — it escapes to the fail-closed forward drop and the LAN goes
-	// dark. Re-asserted on EVERY apply, never fast-pathed: netifd recreating a
-	// bridge (`ifup lan`, a VLAN change) hands back a device with the kernel
-	// defaults, silently un-setting accept_local behind our back. Fail-closed like
-	// the other netplane steps: return without teardown.
-	if err := netplane.ApplyIfaceSysctlsAt(m, now); err != nil {
-		return changed, err
-	}
-
-	// The plane is COMPLETE only here: table + policy routing + sysctls. ApplyNft
-	// already flushed the DNS conntrack when it loaded the ruleset, but that is
-	// one step too early — ApplyRouting is idempotent BY del-then-add, so it opens
-	// a window in which the fwmark rule is momentarily absent, and any DNS flow
-	// that crosses that window is tracked against a plane that is still being
-	// assembled. Flushing once more now that every piece is in place is what makes
-	// "no entry survives the transition" actually true. Only on a real change (the
-	// fast path assembled nothing), best-effort, and cheap: the :53 entry count is
-	// bounded by the number of clients.
-	if !nftCurrent {
-		if n, ferr := netplane.FlushDNSConntrack(); ferr != nil {
-			a.log.Debug("flush DNS conntrack after plane change: ", ferr)
-		} else if n > 0 {
-			a.log.Debug("plane changed: dropped ", n, " stale DNS conntrack entries")
-		}
+	plane, perr := applyDataPlane(a, m, opts, now)
+	if perr != nil {
+		// The engine is ALREADY running the new config at this point, and the data
+		// plane is not — so nothing the previous apply published is true any more.
+		// Publishing is what this branch used to skip entirely; see abortAfterSwap.
+		return changed, a.abortAfterSwap(m, plane, warnings, configWarnings, perr)
 	}
 
 	// (4) success. Bump the effective-state generation ONLY when something really
 	// moved: a no-op reconcile must not invalidate an armed commit-confirm window
 	// (cron reconciles every minute — counting those would cancel every rollback
 	// that commit-confirm exists to guarantee).
-	if changed || !nftCurrent {
+	if changed || plane.changed {
 		a.stateGen.Add(1)
 	}
 	a.setHolding(false)
@@ -544,7 +464,8 @@ func (a *Applier) applyLocked(m *model.Model) (bool, error) {
 	// correctly so here: an egress that cannot reach off its own subnet is a configured
 	// path that silently carries nothing, exactly the class of fault that channel exists
 	// for.
-	ws := collectWarnings(m.Globals, warnings, append(nftWarnings, routeWarnings...), configWarnings, untunPlan.Notes()...)
+	ws := collectWarnings(m.Globals, warnings,
+		append(plane.nftWarnings, plane.routeWarnings...), configWarnings, plane.planNotes...)
 	a.setWarnings(ws)
 	// The log only hears about a CHANGE. Status above always carries the full set;
 	// reprinting it on every no-op reconcile (cron, once a minute, plus every
@@ -559,6 +480,187 @@ func (a *Applier) applyLocked(m *model.Model) (bool, error) {
 	return changed, nil
 }
 
+// planeOutcome is what the netplane half of an apply did, carried back to
+// applyLocked so the SAME facts can be published whether it succeeded or failed.
+// Before it existed, everything the netplane stage learned — the warnings it
+// rendered, the notes the untunnelable plan produced — was thrown away on any
+// error, which is why a failed apply left the previous config's verdict standing.
+type planeOutcome struct {
+	// changed is true when the nft ruleset was actually (re)loaded, i.e. the data
+	// plane moved. Distinct from the engine's own `changed`: the engine hash covers
+	// option.Options only, so a purely netplane-visible change hashes identical.
+	changed bool
+	// stage names the netplane step that failed, in operator words, or "" on
+	// success. It is what the failure warning is addressed to.
+	stage         string
+	planNotes     []string
+	nftWarnings   []string
+	routeWarnings []string
+}
+
+// engineApply and applyDataPlane are the two heavy halves of applyLocked, behind
+// package-level seams for exactly one reason: the PUBLISHING behaviour around
+// them (what Status says after a stage fails) is the thing this file gets wrong
+// most easily and can otherwise only be tested on a router, with root, a real
+// sing-box instance and a real nft binary — i.e. never, in the gate. Production
+// always runs the real methods; a test substitutes a stage that fails and asserts
+// what the operator is then told. Same seam pattern as applyHoldNft.
+var (
+	engineApply    = func(a *Applier, opts option.Options) (bool, error) { return a.eng.Apply(opts) }
+	applyDataPlane = (*Applier).applyDataPlaneLocked
+)
+
+// applyDataPlaneLocked is step (3) of the pipeline: nft ruleset, policy routing
+// and sysctls, in that order, fail-closed. Caller holds a.mu and has ALREADY
+// swapped the engine, so every failure here leaves the router in a mixed state —
+// which is why the outcome is returned even on error.
+func (a *Applier) applyDataPlaneLocked(m *model.Model, opts option.Options, now time.Time) (planeOutcome, error) {
+	// Render FIRST, then decide whether anything needs re-asserting. Gating the
+	// whole data plane on the engine's `changed` flag alone was wrong: the engine
+	// hash covers option.Options only, so a purely netplane-visible change (the
+	// kill-switch flipping open->closed, DNS force-intercept, a rule gaining an
+	// iface:/zone: source, an inbound device rename) hashed identical, took the
+	// fast-path, and left the OLD ruleset loaded while the panel reported success.
+	// A stale-but-loaded fail-open table is exactly the leak this audit is about.
+	// Resolve WHERE the untunnelable-protocol drop applies before rendering. The
+	// engine is already running by this point (step 2), so its loaded rule-sets can
+	// supply the addresses a geoip list contributes; a stopped engine or a list that
+	// has not downloaded yet yields no plan and the conservative blanket drop.
+	//
+	// The resolved addresses are rendered INTO the ruleset text, so the idempotence
+	// check below sees them: a refreshed geoip list changes the text and triggers a
+	// real reload, rather than leaving a stale plan loaded (the D3 trap).
+	untunPlan := a.untunnelablePlanFor(m, opts)
+	out := planeOutcome{planNotes: untunPlan.Notes()}
+
+	ruleset, nftWarnings, err := netplane.RenderNftPlanAt(m, untunPlan, now)
+	out.nftWarnings = nftWarnings
+	if err != nil {
+		// Includes the refusal on an unusable interface name with a closed
+		// kill-switch: the previous ruleset stays loaded and keeps protecting the
+		// LAN while the operator fixes the name.
+		out.stage = "rendering the nft ruleset"
+		return out, err
+	}
+	nftCurrent := ruleset == a.lastNft && netplane.TableExists()
+	if !nftCurrent {
+		if err := netplane.ApplyNft(ruleset); err != nil {
+			// The engine may be up, but with no table loaded nothing is diverted into
+			// it — LAN traffic goes straight out the WAN. That is the same silent
+			// fail-open as a dead engine, so it gets the same answer: if there is no
+			// table at all, hold the line rather than leave the LAN exposed.
+			if !netplane.TableExists() {
+				a.holdLocked(m, err)
+			}
+			out.stage = "loading the nft ruleset"
+			return out, err
+		}
+		a.lastNft = ruleset
+		out.changed = true
+	}
+	// ApplyRouting is idempotent by del-then-add, which means it opens a brief
+	// window with NO fwmark rule installed — during it, diverted packets miss the
+	// `local default dev lo` table. Harmless on a real change (the plane is being
+	// rebuilt anyway), but pointless churn on a no-op reconcile, so skip it when
+	// the ruleset is unchanged AND the rule is verifiably still installed.
+	// routeWarnings carries an egress that was BUILT but cannot route (no nexthop on a
+	// non-point-to-point device). It is deliberately part of the status warning set:
+	// such an egress looks applied everywhere in the UI while being unable to reach
+	// anything off its own subnet. On the fast path nothing was rebuilt, so there is
+	// nothing new to report and the previous set stands.
+	if !nftCurrent || !netplane.RoutingPresent(m.Globals) {
+		routeWarnings, rerr := netplane.ApplyRoutingWithWarnings(m)
+		out.routeWarnings = routeWarnings
+		if rerr != nil {
+			out.stage = "installing the policy routing"
+			return out, rerr
+		}
+	}
+	if err := netplane.ApplySysctl(); err != nil {
+		out.stage = "setting the kernel sysctls"
+		return out, err
+	}
+	// Per-diverted-ingress-iface knobs (accept_local/rp_filter): the static
+	// ApplySysctl above cannot know the LAN device names, and without
+	// accept_local=1 on the ingress iface the tproxied packet never reaches the
+	// engine socket — it escapes to the fail-closed forward drop and the LAN goes
+	// dark. Re-asserted on EVERY apply, never fast-pathed: netifd recreating a
+	// bridge (`ifup lan`, a VLAN change) hands back a device with the kernel
+	// defaults, silently un-setting accept_local behind our back. Fail-closed like
+	// the other netplane steps: return without teardown.
+	if err := netplane.ApplyIfaceSysctlsAt(m, now); err != nil {
+		out.stage = "setting the per-interface sysctls"
+		return out, err
+	}
+
+	// The plane is COMPLETE only here: table + policy routing + sysctls. ApplyNft
+	// already flushed the DNS conntrack when it loaded the ruleset, but that is
+	// one step too early — ApplyRouting is idempotent BY del-then-add, so it opens
+	// a window in which the fwmark rule is momentarily absent, and any DNS flow
+	// that crosses that window is tracked against a plane that is still being
+	// assembled. Flushing once more now that every piece is in place is what makes
+	// "no entry survives the transition" actually true. Only on a real change (the
+	// fast path assembled nothing), best-effort, and cheap: the :53 entry count is
+	// bounded by the number of clients.
+	if out.changed {
+		if n, ferr := netplane.FlushDNSConntrack(); ferr != nil {
+			a.log.Debug("flush DNS conntrack after plane change: ", ferr)
+		} else if n > 0 {
+			a.log.Debug("plane changed: dropped ", n, " stale DNS conntrack entries")
+		}
+	}
+	return out, nil
+}
+
+// abortAfterSwap publishes an honest status for an apply that got PAST the engine
+// swap and then failed in the data plane, and returns the cause unchanged.
+//
+// The defect it exists for: every netplane failure used to `return changed, err`
+// before setTraffic/setWarnings, so Status kept serving the verdict and the
+// findings of the PREVIOUS config while the engine was already running the new
+// one. Worse, it did not self-heal — the next cron reconcile hashes identical,
+// fails at the same stage, and returns at the same place, so the stale verdict
+// stood for as long as the fault did. A green "Protected" over a half-installed
+// plane is the exact inversion this audit is about: not an error shown when
+// things are fine, but calm shown when they are not.
+//
+// What it publishes:
+//
+//   - Traffic goes back to UNKNOWN (the zero value). It is tempting to publish
+//     TrafficOf(opts) here, since the ENGINE really is running those options — but
+//     the verdict describes where the LAN's traffic ends up, and that is decided by
+//     the engine and the data plane together. With one of them from this config and
+//     the other from the last one, the honest answer is that we do not know; the
+//     panel renders unknown, and is required never to render it as protected.
+//   - The warning set is replaced by THIS config's warnings, with a critical entry
+//     naming the stage that failed at the front. The operator gets the news about
+//     the config that is actually loaded, plus the fact that it is only half loaded.
+//
+// Caller holds a.mu.
+func (a *Applier) abortAfterSwap(m *model.Model, plane planeOutcome, generateWarnings []string, configWarnings []model.Warning, cause error) error {
+	a.setTraffic(generate.Traffic{})
+
+	stage := plane.stage
+	if stage == "" {
+		stage = "installing the data plane"
+	}
+	ws := gatherWarnings(m.Globals, generateWarnings,
+		append(plane.nftWarnings, plane.routeWarnings...), configWarnings, plane.planNotes...)
+	ws = finalizeWarnings(append([]Warning{{
+		Severity: SeverityCritical,
+		Section:  "netplane",
+		Name:     stage,
+		Message: fmt.Sprintf("the engine was switched to this configuration but the data plane could NOT be "+
+			"completed — %s failed: %v. What the kernel holds is part of this configuration and part of the "+
+			"previous one, so where your traffic goes is UNKNOWN: treat this router as unprotected until a "+
+			"reconcile succeeds. It is retried every minute; if it keeps failing, fix the cause or roll back.",
+			stage, cause),
+	}}, ws...))
+	a.setWarnings(ws)
+	a.logWarningsIfChanged(ws)
+	return cause
+}
+
 // holdLocked installs the fail-closed HOLDING PLANE when the engine is not
 // running and the kill-switch is closed. Caller holds a.mu.
 //
@@ -940,12 +1042,28 @@ func (a *Applier) Rollback() error {
 	defer release()
 	a.mu.Lock()
 	defer a.mu.Unlock()
-	if err := a.eng.Rollback(); err != nil {
+	m, err := rollbackEngineAndPlane(a)
+	if err != nil {
 		return err
 	}
+	a.publishEngineRollback(m)
+	return nil
+}
+
+// rollbackEngineAndPlane is the ACTION half of the no-snapshot rollback: drive the
+// engine back to its predecessor config and re-assert the data plane from current
+// UCI. It returns the model the plane was rebuilt from. Caller holds a.mu.
+//
+// It is a variable for the same reason as engineApply/applyDataPlane: what this
+// rollback PUBLISHES afterwards is the part that was wrong, and it cannot be
+// exercised at all without two real engine generations and a real nft binary.
+var rollbackEngineAndPlane = func(a *Applier) (*model.Model, error) {
+	if err := a.eng.Rollback(); err != nil {
+		return nil, err
+	}
 	m, err := model.ReadUCI()
 	if err != nil {
-		return err
+		return nil, err
 	}
 	// One clock for the whole re-assert, same as applyLocked: the ruleset's
 	// divert set and the iface sysctls below must agree on the profile-effective
@@ -957,14 +1075,14 @@ func (a *Applier) Rollback() error {
 		a.log.Warn("netplane: ", w)
 	}
 	if err != nil {
-		return err
+		return nil, err
 	}
 	if err := netplane.ApplyNft(ruleset); err != nil {
-		return err
+		return nil, err
 	}
 	a.lastNft = ruleset
 	if err := netplane.ApplyRouting(m); err != nil {
-		return err
+		return nil, err
 	}
 	// The sysctl half must be re-asserted here too. It used to be missing: a
 	// rollback that changes the set of diverted ingress devices (a different
@@ -973,9 +1091,60 @@ func (a *Applier) Rollback() error {
 	// then never reaches the engine socket and that network goes dark after a
 	// rollback, which is precisely when the operator can least afford it.
 	if err := netplane.ApplySysctl(); err != nil {
-		return err
+		return nil, err
 	}
-	return netplane.ApplyIfaceSysctlsAt(m, now)
+	if err := netplane.ApplyIfaceSysctlsAt(m, now); err != nil {
+		return nil, err
+	}
+	return m, nil
+}
+
+// publishEngineRollback makes Status describe the router the no-snapshot rollback
+// just produced, instead of the one it rolled away FROM. Caller holds a.mu.
+//
+// The defect: this path touched none of the publishers. Apply a tunnel config,
+// Confirm it (which consumes the snapshot), then roll back later — the engine goes
+// to its predecessor, which may well be the `default -> direct` config, and the
+// panel keeps showing the tunnel verdict and the tunnel config's warnings, in
+// green, indefinitely. The whole LAN is on the plain WAN with its real address and
+// the UI says Protected. Nothing else corrects it: the verdict is only ever
+// rewritten by a successful apply, and a rollback is not one.
+//
+// The verdict published is UNKNOWN, not a computed one, and that is the honest
+// answer rather than a lazy one: engine.Rollback re-applies option.Options that
+// this process no longer holds (the engine keeps them, apply does not), so there
+// is nothing here to run generate.TrafficOf over. Guessing from current UCI would
+// be worse than saying nothing — UCI is the config we rolled AWAY from. Unknown is
+// rendered as unknown by the panel and never as protected, and the next reconcile
+// (cron, within a minute) replaces it with the truth.
+func (a *Applier) publishEngineRollback(m *model.Model) {
+	a.setTraffic(generate.Traffic{})
+	a.setHolding(false) // a full plane was just loaded; whatever hold there was is over
+	// lastGood is the teardown/rollback target, and the data plane was just built
+	// from m — so m is what a later Teardown must know about to remove the right
+	// marks and routing tables.
+	a.lastGood = m
+	// The observatory's reachability plan was built from the config we rolled away
+	// from: left running it probes outbounds that may no longer exist and files the
+	// results against tags the running box does not have. There is no plan to
+	// replace it with (see above), so stop probing until the next apply installs one.
+	if a.eng != nil {
+		a.eng.StopObservatory()
+	}
+	ws := finalizeWarnings([]Warning{{
+		Severity: SeverityCritical,
+		Section:  "engine",
+		Name:     "rollback",
+		Message: "the engine was rolled back to the configuration that ran before the current one. " +
+			"That configuration is not the one on disk, so where your traffic goes and what was left " +
+			"un-applied are both UNKNOWN until the next reconcile (within a minute) re-applies the " +
+			"saved config and reports on it. Do not read this router as protected in the meantime.",
+	}})
+	a.setWarnings(ws)
+	a.logWarningsIfChanged(ws)
+	// The plane moved, so an armed commit-confirm watcher must see a changed
+	// generation and stand down rather than clobber what we just restored.
+	a.stateGen.Add(1)
 }
 
 // canRollback reports whether Rollback would actually revert something: an armed
@@ -1019,11 +1188,30 @@ func ActiveFlagPresent() bool {
 
 // Status is the read-side snapshot printed by `shaterd status` as JSON.
 //
-//	running  the daemon process is up (a live socket reply => true; the offline
-//	         stub reports false). Whether the ENGINE is intercepting is carried by
-//	         active/table/hash, not by running — a daemon can be up but inert.
+//	running  SHATER IS RUNNING: the daemon answered AND its engine has a started
+//	         sing-box instance carrying a config. false therefore covers every way
+//	         of not proxying — daemon down, daemon up with a dead engine, disabled,
+//	         torn down — and the fields below say which.
+//
+//	         It used to be the literal `true`, on the reasoning that Status() is
+//	         only ever called from inside the live daemon. That was true and it was
+//	         useless: a constant cannot report anything, and the panel built its
+//	         headline on `running && active`, so the "not running" branch was
+//	         physically unreachable and an engine that never started showed green.
+//	         A field whose only possible value is the reassuring one is worse than
+//	         no field: it is a promise the code cannot break.
+//
+//	         "Is the daemon process alive?" is a different question and is answered
+//	         by whether the status call returned at all (plus uptime_seconds, which
+//	         only a live daemon can produce).
 //	enabled  globals.enabled in UCI.
-//	active   ACTIVE_FLAG present (a successful enabled apply raised it).
+//	active   ACTIVE_FLAG present. This is the "the service is meant to be running"
+//	         latch that gates hotplug and cron, NOT a health signal: it is raised by
+//	         a successful enabled apply and cleared only by teardown, so it stays up
+//	         while the engine is down and the fail-closed holding plane is blocking
+//	         the LAN — deliberately, because clearing it would switch off the very
+//	         cron reconcile that brings the engine back. Never render it as "we are
+//	         proxying"; that is what running/plane/traffic are for.
 //	table    the `inet shater` nft table is loaded.
 //	hash     the running engine's config hash ("" when the engine is not started).
 //	kill_switch globals.kill_switch in UCI (closed = fail-closed, open = leaky).
@@ -1044,9 +1232,14 @@ type Status struct {
 	PanelPort   int    `json:"panel_port"`
 	CanRollback bool   `json:"can_rollback"`
 
-	// EngineRunning is whether a sing-box instance is actually started. It is the
-	// honest answer to "are we proxying?", which running/active/table each only
-	// approximate.
+	// EngineRunning is whether a sing-box instance is actually started.
+	//
+	// It was added as the honest field to stand beside a `running` that was hard-wired
+	// true, and no consumer ever read it. Now that running carries the same fact it is
+	// kept as its explicit, unambiguous name — the two are equal by construction from
+	// the daemon — because it is already in the published API and reading
+	// `engine_running` in a client is self-documenting where `running` needs this
+	// comment.
 	EngineRunning bool `json:"engine_running"`
 
 	// Plane describes what is loaded in the kernel RIGHT NOW:
@@ -1141,18 +1334,23 @@ func processUptime(now time.Time) (startedUnix, uptimeSeconds int64) {
 	return now.Unix() - uptimeSeconds, uptimeSeconds
 }
 
-// Status returns the live status from this daemon's engine + kernel state. It is
-// only ever called from within the running daemon, so running=true; engine state
-// is reflected by Active/Table/Hash (an inert daemon reports running=true but
-// active=false/table=false/hash="").
+// Status returns the live status from this daemon's engine + kernel state.
+//
+// It is only ever called from within the running daemon, which is exactly why
+// `running` is read off the engine rather than set to true: from in here the
+// daemon's own liveness is a tautology, and the only thing left worth reporting
+// under that name is whether shater is carrying any traffic. A daemon that is up
+// with a dead engine reports running=false, plane="hold"/"none" and an unknown
+// traffic verdict — which is the state this field exists to make expressible.
 func (a *Applier) Status() Status {
+	engineUp := a.eng != nil && a.eng.Running()
 	s := Status{
-		Running:       true,
+		Running:       engineUp,
 		Active:        ActiveFlagPresent(),
 		Table:         netplane.TableExists(),
 		Hash:          a.eng.Hash(),
 		CanRollback:   a.canRollback(),
-		EngineRunning: a.eng.Running(),
+		EngineRunning: engineUp,
 		Traffic:       a.Traffic(),
 		Warnings:      a.Warnings(),
 	}

shater/apply/honesty_test.go

@@ -0,0 +1,178 @@
+package apply
+
+// Regression tests for the three ways this package used to report calm over a
+// router that was not doing what its config said. Each of them is the INVERTED
+// failure — not an error shown when things are fine, but green shown when they
+// are not — which is the only kind that gets someone hurt.
+
+import (
+	"errors"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/sagernet/sing-box/option"
+	"github.com/sagernet/sing-box/shater/engine"
+	"github.com/sagernet/sing-box/shater/generate"
+	"github.com/sagernet/sing-box/shater/model"
+)
+
+// TestStatusRunningReportsTheEngine pins the contract the panel headline is built
+// on.
+//
+// `running` used to be the literal `true` in the only code path that produces it,
+// so `running && active` — what the panel reads — could not go false however dead
+// the engine was, and the "not running" branch was unreachable code. A status
+// field that can only ever hold the reassuring value is not a weak signal, it is
+// an unfalsifiable claim.
+func TestStatusRunningReportsTheEngine(t *testing.T) {
+	a := New(engine.New(), nil)
+
+	// A fresh applier's engine has never started: nothing is being proxied, and
+	// the status must be able to say so.
+	s := a.Status()
+	if s.Running {
+		t.Errorf("Status().Running = true with a stopped engine — the field is a constant again")
+	}
+	if s.Running != s.EngineRunning {
+		t.Errorf("running (%v) and engine_running (%v) must agree: they are the same fact",
+			s.Running, s.EngineRunning)
+	}
+
+	// And the hold state — engine down, LAN blocked — must not read as running
+	// either. This is the three-green-lamps case: holding does not clear the
+	// ACTIVE flag (cron needs it to keep retrying), so `active` alone cannot say it.
+	g := model.DefaultGlobals()
+	g.KillSwitch = "open" // the early-return branch of holdLocked
+	a.mu.Lock()
+	a.holdLocked(&model.Model{Globals: g}, errors.New("engine start failed"))
+	a.mu.Unlock()
+	if a.Status().Running {
+		t.Errorf("Status().Running = true while the engine is down and the plane is held")
+	}
+}
+
+// TestApplyFailingAfterEngineSwapDropsTheOldVerdict is the defect-3 regression.
+//
+// Everything after the engine swap used to `return changed, err` before
+// setTraffic/setWarnings, so a netplane failure left Status serving the VERDICT
+// and the FINDINGS of the configuration that no longer runs. It did not self-heal
+// either: the next cron reconcile hashes identical, fails at the same stage and
+// returns at the same place, so the stale green stood for as long as the fault.
+func TestApplyFailingAfterEngineSwapDropsTheOldVerdict(t *testing.T) {
+	a := New(engine.New(), nil)
+
+	// What the previous, fully successful apply published.
+	a.setTraffic(generate.Traffic{Verdict: generate.VerdictTunnel, Default: "auto", TunnelRules: 3})
+	a.setWarnings([]Warning{{
+		Severity: SeverityCritical, Section: "ruleset", Name: "stale",
+		Message: "a finding of the configuration that is no longer running",
+	}})
+
+	// The engine swap succeeds; the data plane does not.
+	restore := stubApplyStages(t,
+		func(a *Applier, opts option.Options) (bool, error) { return true, nil },
+		func(a *Applier, m *model.Model, opts option.Options, now time.Time) (planeOutcome, error) {
+			return planeOutcome{stage: "loading the nft ruleset"}, errors.New("nft: permission denied")
+		})
+	defer restore()
+
+	a.mu.Lock()
+	_, err := a.applyLocked(holdModel("closed"))
+	a.mu.Unlock()
+	if err == nil {
+		t.Fatalf("applyLocked must surface the netplane failure")
+	}
+
+	s := a.Status()
+	if s.Traffic.Verdict != "" {
+		t.Errorf("Traffic.Verdict = %q after a half-installed plane, want \"\" (unknown): "+
+			"the engine runs the new config and the kernel does not, so nobody knows where traffic goes",
+			s.Traffic.Verdict)
+	}
+	var sawAbort bool
+	for _, w := range s.Warnings {
+		if strings.Contains(w.Message, "a finding of the configuration that is no longer running") {
+			t.Errorf("the previous config's findings are still published: %+v", w)
+		}
+		if w.Section == "netplane" && strings.Contains(w.Message, "could NOT be completed") {
+			sawAbort = true
+			if w.Severity != SeverityCritical {
+				t.Errorf("an incomplete data plane is critical, got %q", w.Severity)
+			}
+			if !strings.Contains(w.Message, "loading the nft ruleset") {
+				t.Errorf("the warning must name the stage that failed: %q", w.Message)
+			}
+		}
+	}
+	if !sawAbort {
+		t.Errorf("no warning says the data plane is incomplete; warnings = %+v", s.Warnings)
+	}
+}
+
+// TestRollbackWithoutSnapshotRepublishes is the defect-2 regression.
+//
+// Apply a tunnel config, Confirm it (which consumes the commit-confirm snapshot),
+// then roll back later. The no-snapshot branch drives engine.Rollback and rebuilds
+// the plane — and used to touch none of the publishers, so the panel kept showing
+// the tunnel verdict and the tunnel config's warnings in green while the engine
+// had gone back to a predecessor that may route `default -> direct`. The entire
+// LAN on the plain WAN, under a green "Protected", indefinitely.
+func TestRollbackWithoutSnapshotRepublishes(t *testing.T) {
+	a := New(engine.New(), nil)
+	a.setTraffic(generate.Traffic{Verdict: generate.VerdictTunnel, Default: "auto", TunnelRules: 2})
+	a.setWarnings([]Warning{{
+		Severity: SeverityWarning, Section: "chain", Name: "hop",
+		Message: "a finding of the configuration we are rolling away from",
+	}})
+
+	m := holdModel("closed")
+	orig := rollbackEngineAndPlane
+	rollbackEngineAndPlane = func(*Applier) (*model.Model, error) { return m, nil }
+	defer func() { rollbackEngineAndPlane = orig }()
+
+	before := a.stateGen.Load()
+	if err := a.Rollback(); err != nil {
+		t.Fatalf("Rollback: %v", err)
+	}
+
+	s := a.Status()
+	if s.Traffic.Verdict != "" {
+		t.Errorf("Traffic.Verdict = %q after an engine rollback, want \"\" (unknown): the running "+
+			"config is one this process cannot describe", s.Traffic.Verdict)
+	}
+	var sawRollback bool
+	for _, w := range s.Warnings {
+		if strings.Contains(w.Message, "rolling away from") {
+			t.Errorf("the pre-rollback findings are still published: %+v", w)
+		}
+		if w.Section == "engine" && w.Name == "rollback" {
+			sawRollback = true
+			if w.Severity != SeverityCritical {
+				t.Errorf("an undescribable running config is critical, got %q", w.Severity)
+			}
+		}
+	}
+	if !sawRollback {
+		t.Errorf("nothing says the router is running a rolled-back config; warnings = %+v", s.Warnings)
+	}
+	if a.LastGood() != m {
+		t.Errorf("last-good must become the model the data plane was rebuilt from")
+	}
+	if a.stateGen.Load() == before {
+		t.Errorf("the plane moved but stateGen did not: an armed commit-confirm watcher " +
+			"would clobber the config we just restored")
+	}
+}
+
+// stubApplyStages replaces the two heavy halves of applyLocked for the duration of
+// a test and returns the restore func.
+func stubApplyStages(t *testing.T,
+	eng func(*Applier, option.Options) (bool, error),
+	plane func(*Applier, *model.Model, option.Options, time.Time) (planeOutcome, error),
+) func() {
+	t.Helper()
+	origEngine, origPlane := engineApply, applyDataPlane
+	engineApply, applyDataPlane = eng, plane
+	return func() { engineApply, applyDataPlane = origEngine, origPlane }
+}

shater/apply/untunnelable.go

@@ -1,13 +1,19 @@
 package apply
 
-// Deciding WHERE the untunnelable-protocol drop applies.
+// Deciding WHERE the untunnelable-protocol drop applies, for the ONE policy that
+// asks: `icmp`.
 //
 // The data plane cannot tunnel anything that is not TCP or UDP (kernel TPROXY
-// needs a socket; the proxy protocols carry TCP streams and UDP datagrams). The
-// drop that follows from that is only justified for destinations the routing
-// rules actually send THROUGH the tunnel: where a rule routes direct, the
-// client's real address already reaches that destination over TCP, so dropping
-// its ICMP hides nothing and merely breaks diagnostics.
+// needs a socket; the proxy protocols carry TCP streams and UDP datagrams). Where
+// a rule routes direct, the client's real address already reaches that
+// destination over TCP, so dropping its ICMP hides nothing and merely breaks
+// diagnostics.
+//
+// That reasoning used to govern `block` as well, which made `block` identical to
+// `direct` under the ordinary "tunnel the blocked list, send the rest direct"
+// configuration — see the essay in netplane/untunnelable.go. `block` now drops
+// unconditionally and `direct` allows unconditionally; neither reads this file,
+// and untunnelablePlanFor no longer builds a plan for them at all.
 //
 // This file computes the difference, by walking the FULLY RESOLVED routing rules
 // that generate produced. Using generate's output rather than the raw model is
@@ -239,9 +245,31 @@ func buildUntunnelablePlan(opts option.Options, lookup ruleSetCIDRs) *netplane.U
 		}
 		mt.AnyDst = !hasDstMatcher
 		mt.Dst4, mt.Dst6 = netplane.PrefixStrings(dst)
+		if !mt.AnyDst && len(mt.Dst4) == 0 && len(mt.Dst6) == 0 {
+			// The rule names addresses and not one of them survived into a form the
+			// data plane can express — unparseable, or IPv4-mapped IPv6, which
+			// PrefixStrings drops because nftables has no set type for it. The step
+			// would render no line at all, so the walk would silently step OVER a
+			// rule that CAN claim this traffic and let a later rule decide in its
+			// place. That is the over-permissive mistake this file exists to avoid,
+			// so it is undecidable rather than skippable.
+			plan.Warnings = append(plan.Warnings,
+				"a routing rule's addresses cannot be expressed by the firewall, so ping/IPTV/"+
+					"VPN-passthrough traffic is blocked from that rule onwards")
+			return plan
+		}
 
-		// Source predicate, when the rule is scoped to particular clients.
+		// Source predicate, when the rule is scoped to particular clients. Same
+		// reasoning as above, and here the consequence is worse than a skipped step:
+		// an empty source pair reads as "any source", so an ALLOW scoped to three lab
+		// machines would render as an allow for the whole LAN.
 		mt.Src4, mt.Src6 = netplane.PrefixStrings(parsePrefixes(d.SourceIPCIDR))
+		if len(d.SourceIPCIDR) > 0 && len(mt.Src4) == 0 && len(mt.Src6) == 0 {
+			plan.Warnings = append(plan.Warnings,
+				"a routing rule's source addresses cannot be expressed by the firewall, so ping/IPTV/"+
+					"VPN-passthrough traffic is blocked from that rule onwards")
+			return plan
+		}
 
 		plan.Matches = append(plan.Matches, mt)
 
@@ -419,10 +447,17 @@ func parsePrefixes(in []string) []netip.Prefix {
 // rule-set addresses against the RUNNING engine. A nil engine (or a stopped one)
 // yields lookups that always report "not loaded", so the plan degrades to the
 // conservative blanket drop on its own.
+//
+// ONLY `icmp` has a use for it. The other two rungs are unconditional — `direct`
+// allows every untunnelable protocol wherever it was going, `block` allows none —
+// and netplane.untunnelableRules refuses to consult the plan for either. Building
+// one anyway would push the routing rules' whole address space into kernel memory
+// (geoip-us alone is ~159 000 prefixes, ~20 MB) to answer a question nothing asks;
+// worse, it would render the sets into the ruleset text, so a geoip refresh would
+// churn the data plane for a policy that cannot use it. Since `block` is the
+// DEFAULT, this is the stock install's path.
 func (a *Applier) untunnelablePlanFor(m *model.Model, opts option.Options) *netplane.UntunnelablePlan {
-	if netplane.EffectiveUntunnelable(m.Globals) == netplane.UntunnelableDirect {
-		// Everything untunnelable is allowed regardless of destination; computing
-		// (and loading into the kernel) thousands of prefixes would change nothing.
+	if netplane.EffectiveUntunnelable(m.Globals) != netplane.UntunnelableICMP {
 		return nil
 	}
 	lookup := func(tag string) ([]netip.Prefix, bool) { return nil, false }

shater/apply/untunnelable_test.go

@@ -63,11 +63,31 @@ func renderPlan(t *testing.T, m *model.Model, plan *netplane.UntunnelablePlan) s
 	return rs
 }
 
+// icmpPolicy puts the model on the ONE policy that consults the destination plan.
+//
+// Every assertion about the WALK's rendered form has to be made under it, and
+// that is a change of contract rather than test bookkeeping: `block` now drops
+// every untunnelable protocol unconditionally and `direct` accepts every one of
+// them unconditionally, so netplane.untunnelableRules refuses to read the plan for
+// either. A render-level test left on the default policy would be asserting
+// against a section the renderer no longer writes — which is exactly how the
+// defect survived: it was `block` rendering `direct`, under a test that read the
+// resulting accept as the feature working.
+func icmpPolicy(m *model.Model) *model.Model {
+	m.Globals.Untunnelable = netplane.UntunnelableICMP
+	return m
+}
+
 // TestOnlyPinnedAddressIsTunnelled is the first scenario from the brief: a rule
 // sends ONLY 8.8.8.8/32 through the tunnel and everything else goes direct, so
 // only 8.8.8.8 may be un-pingable and the rest of the internet must answer.
+//
+// The PLAN half is unchanged — the walk still resolves the pinned address to a
+// deny and everything else to the routing default. Only the rendering moved to
+// `icmp` (see icmpPolicy). What `block` renders for this same configuration is
+// TestBlockDropsEvenWhenEverythingRoutesDirect, and it is nothing at all.
 func TestOnlyPinnedAddressIsTunnelled(t *testing.T) {
-	m := tunnelModel()
+	m := icmpPolicy(tunnelModel())
 	m.Rulesets = []model.Ruleset{pinnedIPSet("pin", "8.8.8.8/32")}
 	m.Rules = []model.Rule{
 		{Name: "pin", Enabled: true, Order: 10, DstRuleset: []string{"pin"}, Target: "group:auto"},
@@ -106,10 +126,128 @@ func TestOnlyPinnedAddressIsTunnelled(t *testing.T) {
 	}
 }
 
+// TestBlockDropsEvenWhenEverythingRoutesDirect is the defect, in the exact
+// configuration that makes it bite.
+//
+// "Tunnel the pinned address, send the rest direct" leaves the ROUTING DEFAULT
+// direct, so the plan's DefaultAllow is true — and `block` used to walk the plan
+// like `icmp` and inherit that default as a blanket
+// `meta l4proto != { tcp, udp } accept`. ICMP, ESP, AH, GRE, IGMP and SCTP all
+// left with the client's real address. That includes a client-run IPsec or PPTP
+// tunnel: a standing second tunnel beside ours, carrying arbitrary traffic under a
+// peer we neither route nor filter, for as long as it stays up — which is the very
+// thing the middle rung exists to keep out of "I just want ping". Meanwhile the
+// panel promised "Nothing leaves except through the tunnel."
+//
+// `block` is the DEFAULT policy, so this was the stock install.
+//
+// RED BEFORE THE FIX: with the old untunnelableRules the rendered forward chain
+// carries `... meta l4proto != { tcp, udp } accept`, emitted from plan.DefaultAllow.
+func TestBlockDropsEvenWhenEverythingRoutesDirect(t *testing.T) {
+	m := tunnelModel()
+	m.Globals.IPv6 = true
+	m.Globals.Untunnelable = netplane.UntunnelableBlock // the default, spelled out: it is the subject
+	m.Rulesets = []model.Ruleset{pinnedIPSet("pin", "8.8.8.8/32")}
+	m.Rules = []model.Rule{
+		{Name: "pin", Enabled: true, Order: 10, DstRuleset: []string{"pin"}, Target: "group:auto"},
+		{Name: "rest", Enabled: true, Order: 99, Target: "direct"},
+	}
+	plan := planFor(t, m, map[string][]string{"rs-pin": {"8.8.8.8/32"}})
+	if !plan.DefaultAllow {
+		t.Fatalf("precondition: this config must yield a plan whose default is ALLOW, or the "+
+			"test is not exercising the defect at all; plan=%+v", plan)
+	}
+
+	fwd := renderPlan(t, m, plan)
+	for _, line := range strings.Split(fwd, "\n") {
+		if !strings.Contains(line, netplane.UntunnelableFilterExpr()) &&
+			!strings.Contains(line, "echo-request") {
+			continue
+		}
+		t.Errorf("block emitted an untunnelable exception although its whole promise is that "+
+			"there are none: %q", strings.TrimSpace(line))
+	}
+	// The drops now carry the entire policy, so losing one would be silent.
+	if !strings.Contains(fwd, "meta nfproto ipv4 drop") ||
+		!strings.Contains(fwd, "meta nfproto ipv6 drop") {
+		t.Fatalf("block lost a fail-closed drop, so nothing enforces it:\n%s", fwd)
+	}
+
+	// And the applier must not even BUILD a plan for block: nothing reads it, and
+	// building one pushes the routing rules' whole address space into kernel memory
+	// and into the ruleset text (a geoip refresh would then churn the data plane
+	// for a policy that cannot use it).
+	opts, _, err := generate.GenerateWithWarnings(m)
+	if err != nil {
+		t.Fatalf("generate: %v", err)
+	}
+	var a Applier
+	if got := a.untunnelablePlanFor(m, opts); got != nil {
+		t.Errorf("block must build no destination plan at all, got %d step(s) / defaultAllow=%v",
+			len(got.Matches), got.DefaultAllow)
+	}
+	m.Globals.Untunnelable = netplane.UntunnelableDirect
+	if got := a.untunnelablePlanFor(m, opts); got != nil {
+		t.Errorf("direct must build no destination plan either, got %+v", got)
+	}
+	if got := a.untunnelablePlanFor(icmpPolicy(m), opts); got == nil {
+		t.Errorf("icmp is the policy that needs the plan; it must still get one")
+	}
+}
+
+// TestSourceScopedRuleDoesNotWidenTheOtherFamily: a step scoped to IPv6 clients
+// must emit no IPv4 line at all.
+//
+// emit() only wrote `ip saddr @set` when THAT family had prefixes, so a rule whose
+// source_ip_cidr held only IPv6 prefixes rendered an IPv4 line with no source
+// clause whatsoever — an accept for every IPv4 host on the LAN, out of a rule the
+// operator scoped to a handful of v6 addresses. The destination half had always
+// skipped in that situation (`!AnyDst && len(dst) == 0`); the source half was the
+// asymmetry, and the catch-all collapse in buildUntunnelablePlan reads "scoped"
+// as the union of both families, so the two disagreed.
+//
+// RED BEFORE THE FIX: `... ip daddr @unt_d4_0 accept`, with no `ip saddr`.
+func TestSourceScopedRuleDoesNotWidenTheOtherFamily(t *testing.T) {
+	m := icmpPolicy(tunnelModel())
+	m.Globals.IPv6 = true
+	m.Rulesets = []model.Ruleset{pinnedIPSet("lab", "198.51.100.0/24", "2001:db8:70::/48")}
+	m.Rules = []model.Rule{
+		{Name: "lab", Enabled: true, Order: 10, Src: []string{"2001:db8:9::/48"},
+			DstRuleset: []string{"lab"}, Target: "direct"},
+		{Name: "dflt", Enabled: true, Order: 99, Target: "group:auto"},
+	}
+	plan := planFor(t, m, map[string][]string{"rs-lab": {"198.51.100.0/24", "2001:db8:70::/48"}})
+	if len(plan.Matches) != 1 {
+		t.Fatalf("expected one step, got %+v", plan.Matches)
+	}
+	step := plan.Matches[0]
+	if len(step.Src4) != 0 || len(step.Src6) != 1 {
+		t.Fatalf("the step must carry v6 sources only: src4=%v src6=%v", step.Src4, step.Src6)
+	}
+	if len(step.Dst4) != 1 || len(step.Dst6) != 1 {
+		t.Fatalf("the destination list is dual-family: dst4=%v dst6=%v", step.Dst4, step.Dst6)
+	}
+
+	fwd := renderPlan(t, m, plan)
+	for _, line := range strings.Split(fwd, "\n") {
+		if !strings.Contains(line, "@unt_d4_0") {
+			continue
+		}
+		t.Errorf("a rule scoped to IPv6 sources emitted an IPv4 line; with no source clause on "+
+			"it that is an accept for the whole LAN: %q", strings.TrimSpace(line))
+	}
+	// ...and the family the rule really does scope must survive, or the guard
+	// over-corrected into dropping the step entirely.
+	if !strings.Contains(fwd, "ip6 saddr @unt_s6_0") ||
+		!strings.Contains(fwd, "ip6 daddr @unt_d6_0 accept") {
+		t.Errorf("the v6 half of the step was lost:\n%s", fwd)
+	}
+}
+
 // TestCatchAllTunnelDropsEverything is the mirror case: a catch-all rule into the
 // tunnel means nothing is provably direct, so everything untunnelable is dropped.
 func TestCatchAllTunnelDropsEverything(t *testing.T) {
-	m := tunnelModel()
+	m := icmpPolicy(tunnelModel())
 	m.Rules = []model.Rule{{Name: "all", Enabled: true, Order: 99, Target: "group:auto"}}
 	plan := planFor(t, m, nil)
 
@@ -132,7 +270,7 @@ func TestCatchAllTunnelDropsEverything(t *testing.T) {
 // `ru-direct` routes a geoip list direct while everything else is tunnelled, so
 // exactly those addresses become pingable.
 func TestGeoIPRulesetResolvesToPingableAddresses(t *testing.T) {
-	m := tunnelModel()
+	m := icmpPolicy(tunnelModel())
 	m.Globals.IPv6 = true
 	m.Rulesets = []model.Ruleset{{
 		Name: "ru", Type: "ipcidr", Source: "geoip", Categories: []string{"ru"},
@@ -173,7 +311,7 @@ func TestGeoIPRulesetResolvesToPingableAddresses(t *testing.T) {
 // NOT read as "contains no addresses". That would let later rules decide and
 // could allow traffic the plan cannot actually account for.
 func TestUnloadedRuleSetStaysConservative(t *testing.T) {
-	m := tunnelModel()
+	m := icmpPolicy(tunnelModel())
 	m.Rulesets = []model.Ruleset{{
 		Name: "ru", Type: "ipcidr", Source: "geoip", Categories: []string{"ru"},
 	}}
@@ -268,7 +406,7 @@ func TestMigratedDomainAndIPRuleStaysOutOfTheUntunnelablePlan(t *testing.T) {
 	for _, target := range []string{"direct", "block", "group:auto"} {
 		for _, engine := range []string{"up", "down"} {
 			t.Run(target+"/engine-"+engine, func(t *testing.T) {
-				m := migratedRule(target)
+				m := icmpPolicy(migratedRule(target))
 				var loaded map[string][]string
 				if engine == "up" {
 					loaded = map[string][]string{"rs-rule-x": {}, "rs-rule-x-ip": {"203.0.113.0/24"}}
@@ -395,7 +533,7 @@ func TestHugePlanLoadsInFullAndReportsItsSize(t *testing.T) {
 		addr := netip.AddrFrom4([4]byte{10, byte(i >> 16), byte(i >> 8), byte(i)})
 		huge = append(huge, netip.PrefixFrom(addr, 32).String())
 	}
-	m := tunnelModel()
+	m := icmpPolicy(tunnelModel())
 	m.Rulesets = []model.Ruleset{{
 		Name: "big", Type: "ipcidr", Source: "geoip", Categories: []string{"us"},
 	}}
@@ -532,7 +670,14 @@ func TestPlanNeverAcceptsTCPOrUDP(t *testing.T) {
 						strings.TrimSpace(line))
 				}
 			}
-			if policyLines == 0 {
+			// `block` is the exception, and now it is the point: it emits NO
+			// exception line whatsoever. That silence IS the policy — everything
+			// untunnelable falls through to the fail-closed drops below.
+			if policy == netplane.UntunnelableBlock {
+				if policyLines != 0 {
+					t.Errorf("block must emit no untunnelable exception at all:\n%s", fwd)
+				}
+			} else if policyLines == 0 {
 				t.Errorf("policy %q emitted no lines at all:\n%s", policy, fwd)
 			}
 			if !strings.Contains(fwd, "meta nfproto ipv4 drop") ||
@@ -569,7 +714,7 @@ func TestLocalPlaneSurvivesEveryPlan(t *testing.T) {
 // TestSourceScopedRuleNarrowsTheAllow: a rule scoped to particular clients must
 // only grant those clients, not everyone.
 func TestSourceScopedRuleNarrowsTheAllow(t *testing.T) {
-	m := tunnelModel()
+	m := icmpPolicy(tunnelModel())
 	m.Rulesets = []model.Ruleset{pinnedIPSet("lab", "198.51.100.0/24")}
 	m.Rules = []model.Rule{
 		{Name: "lab", Enabled: true, Order: 10, Src: []string{"192.168.9.0/24"},

shater/apply/warnings.go

@@ -74,25 +74,76 @@ type Warning struct {
 	Message string `json:"message"`
 }
 
+// notAppliedTags are the SCREAMING-KEBAB prefixes generate stamps on the one
+// class of warning that means "you configured this protection and it is NOT in
+// force right now". They exist precisely so the condition is greppable and
+// machine-recognisable (generate/ruleset.go, generate/dnsfilter.go say so where
+// they emit them), which makes them a STRUCTURAL signal rather than a guess at
+// wording — so they decide severity outright, before anything else is consulted.
+//
+// This is the fix for the defect that made this whole classifier untrustworthy:
+// the tagged texts say "NOT ACTIVE"/"unreachable right now" in words that matched
+// none of the old markers ("UNREACHABLE" upper-case against "unreachable"
+// lower-case, "is NOT applied" against "is configured but NOT ACTIVE"), and the
+// tag also breaks entityRe below, so a blocklist that failed to download — the
+// single most common real-world fault on this router, and the one the panel has
+// no other way to show — was published as a plain `warning` under section
+// "generate" with no name. Meanwhile `ruleset "x": url source with empty url`
+// parsed cleanly and was graded critical. Severity was, in effect, inverted:
+// a typo shouted, a network outage whispered.
+var notAppliedTags = []string{
+	"RULESET-NOT-APPLIED",    // generate/ruleset.go:821,997,1242
+	"DNS-FILTER-NOT-APPLIED", // generate/dnsfilter.go:132
+}
+
 // criticalMarkers are substrings that identify a warning as "protection you
-// configured is not in effect".
+// configured is not in effect", for the texts that carry neither a tag above nor
+// a protection section below.
 //
 // This is a heuristic over free text, and it is one on purpose: generate emits
 // plain strings today, and inventing a parallel structured warning API across a
 // package boundary owned by another agent would be a far larger change than the
-// problem warrants. The markers below are taken verbatim from the actual warning
-// texts, so they are exact rather than speculative. If generate ever emits its
-// own severity, this list becomes dead code and the conversion simplifies.
+// problem warrants. Every entry below is quoted from a warning that a producer
+// ACTUALLY emits, with the file it comes from — because the previous list had
+// drifted into fiction: five of its nine entries matched no living text at all.
+// Three of those five ("not covered", "fail-closed", "REJECTED") described ONE
+// netplane message (netplane/nft.go:606), which reaches us on the netplane
+// channel and is graded critical wholesale before classify() ever runs; one
+// ("left un-blocked") named a message generate/doh.go:178 records as deleted;
+// one ("UNREACHABLE") was upper-case against a lower-case text. A marker with no
+// producer is not harmless: it reads as coverage, and it is what let the real
+// texts go ungraded for as long as they did.
+//
+// If generate ever emits its own severity, this list becomes dead code and the
+// conversion simplifies.
 var criticalMarkers = []string{
-	"UNREACHABLE",     // remote rule-set/blocklist not applied
-	"is NOT applied",  //  ''
-	"NOT emitted",     // block_doh NXDOMAIN rules missing
-	"left un-blocked", // block_doh: upstream resolver excluded
-	"inert",           // dns_filter / per-device DNS configured but not working
-	"has NO effect",   // dns_mode=fakeip with no fakeip resolver
-	"not covered",     // an interface outside the fail-closed guard
-	"fail-closed",     //  ''
-	"REJECTED",        // an unusable interface name
+	// The DoH NXDOMAIN rules were not built (generate/dns.go:41,67), and a routing
+	// rule whose sources the engine cannot see is not built either
+	// (generate/route.go:113) — in both cases the operator's block simply is not there.
+	"NOT emitted",
+	// dns_filter / per-device DNS / dns_intercept configured but not working
+	// (generate/dns.go:32,35,38,58,61,64) — the filter is on in the UI and filtering nothing.
+	"inert",
+	// A dns_rule that survived parsing but matches nothing (generate/dns.go:987).
+	"has NO effect",
+	// A routing rule that was emitted but whose target is never reached
+	// (generate/route.go:113,115): the traffic the operator sent through a tunnel
+	// follows the rules below it and the default instead. Present tense on purpose —
+	// "never applied" (past) is warnUnreachableRules' wording, which is graded by
+	// consequence a few lines below, not swept in here.
+	"never applies",
+	// A rule scoped to one source that now matches the WHOLE network
+	// (generate/route.go:407, generate/dns.go:992). Whatever the rule does — send a
+	// device direct, point it at another resolver — it now does it to every client,
+	// and nothing else in the UI shows that the scope collapsed.
+	"applies to EVERY client on the router",
+	"apply to ALL clients",
+	// DNS that leaves the router in plaintext to the provider while the UI shows a
+	// configured resolver (generate/dns.go:38,64,410) and node hostnames resolved
+	// direct from the real address (generate/dns.go:469). These are leaks of exactly
+	// the kind the tunnel exists to prevent.
+	"in the clear",
+	"your provider sees",
 	// A condition-less rule retired by a later condition-less rule whose target is
 	// `direct` (generate/route.go warnUnreachableRules): the operator's default
 	// policy — a tunnel, or a block — is not the one the router uses, so everything
@@ -117,6 +168,22 @@ var protectionSections = map[string]bool{
 	"allowlist": true,
 }
 
+// degradedProtectionMarkers are the exceptions to the section rule above: texts
+// about a protection list that is STILL IN EFFECT.
+//
+// Grading these critical is the same defect pointed the other way. The panel's
+// alarm banner lights on critical and on nothing else, so every critical that
+// turns out to be cosmetic teaches the operator that the banner means nothing —
+// and the next one, the one about the blocklist that really did not load, is the
+// one they will not read. In particular the refresh failure is the NORMAL state
+// of a Russian router for minutes at a time: the list is served from the copy
+// compiled earlier and keeps blocking, which is a degradation, not a gap.
+var degradedProtectionMarkers = []string{
+	"continuing with the copy compiled earlier", // generate/ruleset.go:819 — stale but blocking
+	"is IGNORED",                                // generate/ruleset.go:445,472 — a redundant field, the list loads
+	"bad update_interval",                       // generate/ruleset.go:862,1010 — falls back to the default interval
+}
+
 // infoMarkers identify operational notes that are not protection gaps.
 var infoMarkers = []string{"cache:"}
 
@@ -124,26 +191,67 @@ var infoMarkers = []string{"cache:"}
 // consistently, so Section/Name can be recovered from a plain string.
 var entityRe = regexp.MustCompile(`^([a-z_]+) "([^"]*)": (.*)$`)
 
+// tagRe matches the SCREAMING-KEBAB prefix of a tagged warning (see notAppliedTags).
+var tagRe = regexp.MustCompile(`^([A-Z][A-Z0-9-]*): `)
+
+// taggedEntityRe recovers the entity from a TAGGED warning, whose shape is
+//
+//	RULESET-NOT-APPLIED: ruleset "ads" is configured but NOT ACTIVE: ...
+//
+// i.e. the tag sits where entityRe expects the kind, and the entity is followed by
+// prose rather than by ": ". Without this the single most important warning on the
+// router arrived with Section "generate" and no Name, so the panel could neither
+// group it nor link to the list it is about.
+var taggedEntityRe = regexp.MustCompile(`^[A-Z][A-Z0-9-]*: ([a-z_]+) "([^"]*)"`)
+
 // warningFromText normalises one free-text warning. defaultSection is used when
 // the text carries no `kind "name":` prefix.
 func warningFromText(text, defaultSection, severity string) Warning {
 	w := Warning{Severity: severity, Section: defaultSection, Message: strings.TrimSpace(text)}
 	if m := entityRe.FindStringSubmatch(w.Message); m != nil {
 		w.Section, w.Name, w.Message = m[1], m[2], m[3]
+		return w
+	}
+	if m := taggedEntityRe.FindStringSubmatch(w.Message); m != nil {
+		// Attribution only — the message is deliberately left WHOLE. The tag is the
+		// operator's grep handle into `logread` (it is documented as such where it is
+		// emitted), so stripping it to save one repetition of the list's name would
+		// cost the one thing the tag exists for.
+		w.Section, w.Name = m[1], m[2]
 	}
 	return w
 }
 
 // classify picks a severity from the parsed section plus the message text.
-// Section wins where it is decisive (see protectionSections); the markers then
-// catch the global warnings that carry no entity prefix at all.
+//
+// Order is the whole design:
+//
+//  1. a not-applied TAG is structural and decides outright — it is the producer
+//     saying "this protection is off", not us guessing from prose;
+//  2. info markers, so a cache relocation never reads as a fault;
+//  3. the section, for the entity kinds whose entire purpose is to block
+//     something — minus the handful of texts that say the list still works;
+//  4. the free-text markers, which catch the global warnings that carry no entity
+//     prefix at all.
 func classify(section, text string) string {
+	if m := tagRe.FindStringSubmatch(text); m != nil {
+		for _, tag := range notAppliedTags {
+			if m[1] == tag {
+				return SeverityCritical
+			}
+		}
+	}
 	for _, m := range infoMarkers {
 		if strings.Contains(text, m) {
 			return SeverityInfo
 		}
 	}
 	if protectionSections[section] {
+		for _, m := range degradedProtectionMarkers {
+			if strings.Contains(text, m) {
+				return SeverityWarning
+			}
+		}
 		return SeverityCritical
 	}
 	for _, m := range criticalMarkers {
@@ -163,6 +271,15 @@ func classify(section, text string) string {
 //     fail-closed guard does not cover that interface — always critical.
 //   - configWarnings come from model.Validate (already structured).
 func collectWarnings(g model.Globals, generateWarnings, netplaneWarnings []string, configWarnings []model.Warning, planWarnings ...string) []Warning {
+	return finalizeWarnings(gatherWarnings(g, generateWarnings, netplaneWarnings, configWarnings, planWarnings...))
+}
+
+// gatherWarnings is collectWarnings without the sort and the cap, so a caller
+// that must FOLD IN a warning of its own (applyLocked's post-swap failure, which
+// has to say that the data plane is incomplete) can do so and then finalize once.
+// Sorting and capping a list twice is not equivalent: the second pass would drop
+// the "N further warning(s) suppressed" disclosure the first pass appended.
+func gatherWarnings(g model.Globals, generateWarnings, netplaneWarnings []string, configWarnings []model.Warning, planWarnings ...string) []Warning {
 	out := make([]Warning, 0, len(generateWarnings)+len(netplaneWarnings)+len(configWarnings)+1)
 	// The untunnelable-protocol policy always reports what it costs the user; it is
 	// the only one of these that describes correct behaviour rather than a fault.
@@ -186,7 +303,12 @@ func collectWarnings(g model.Globals, generateWarnings, netplaneWarnings []strin
 			Message:  cw.Message,
 		})
 	}
+	return out
+}
 
+// finalizeWarnings sorts critical-first and applies the cap. Call it exactly once
+// per published set.
+func finalizeWarnings(out []Warning) []Warning {
 	// Stable sort by descending severity so the cap can only drop the least
 	// important entries, and the panel gets the worst news first.
 	sort.SliceStable(out, func(i, j int) bool {
@@ -241,33 +363,61 @@ func untunnelablePolicyWarnings(g model.Globals, planNotes []string) []Warning {
 	// With the kill switch open the forward chain has no drops at all, so nothing
 	// is restricted whatever the policy says. Saying that is more useful than
 	// repeating a promise which is not being kept.
+	//
+	// Neither this note nor the `direct` one below may claim IPTV, for the same
+	// reason the `block` note disclaims it: multicast does not cross this router
+	// under ANY of the three settings. The stream itself is WAN-side inbound and
+	// these rules never match it, and a client's outbound multicast UDP is dropped
+	// by the fail-closed guard regardless of the policy. Promising it here would be
+	// the identical lie to the one just removed from `block`, only in the branch
+	// where the operator is least likely to go looking for the cause.
 	if !killSwitchClosed(g) {
 		if policy == netplane.UntunnelableDirect {
 			return out
 		}
 		return note(policy,
-			"This setting has no effect while the kill switch is open: with the kill switch open "+
-				"nothing is blocked, so ping, IPTV and VPN passthrough all work — and all of them "+
-				"reach the internet with your real IP address.")
+			"This setting has no effect while the kill switch is open: with the kill switch open the "+
+				"forward chain has no drops at all, so ping, traceroute and raw VPN passthrough "+
+				"(IPsec ESP/AH, PPTP/GRE) all work — and every one of them reaches the internet with "+
+				"your real IP address. IPTV is not part of that: multicast does not pass this router "+
+				"on any setting, which is a separate matter from this one.")
 	}
 
 	switch policy {
 	case netplane.UntunnelableDirect:
 		return note(policy,
-			"Ping, IPTV and VPN passthrough (IPsec/PPTP) work everywhere, but they go straight out "+
-				"with your real IP address instead of through the tunnel — they are the kinds of "+
-				"traffic a tunnel cannot carry.")
+			"Ping and traceroute work everywhere, and so does raw VPN passthrough (IPsec ESP/AH, "+
+				"PPTP/GRE) — but all of it goes straight out with your real IP address instead of "+
+				"through the tunnel, because a tunnel cannot carry this kind of traffic. VPNs that "+
+				"run over UDP (WireGuard, OpenVPN-UDP, IPsec through NAT) are ordinary tunnelled "+
+				"traffic and are unaffected either way. IPTV is not covered by this setting at all: "+
+				"multicast does not pass this router on any of the three, so switching to `direct` "+
+				"will not bring it back.")
 	case netplane.UntunnelableICMP:
 		return note(policy,
 			"Ping and traceroute work everywhere, including addresses you send through the tunnel; "+
 				"the host you ping sees your real IP address. IPTV and VPN passthrough (IPsec/PPTP) "+
 				"work only toward addresses your rules route directly.")
 	default:
+		// This text used to say these things "work only toward addresses your rules
+		// route directly". That was written when a `direct` route final made the
+		// untunnelable drop degenerate into a blanket accept — i.e. when the note was
+		// describing the bug rather than the policy. netplane now blocks what it says
+		// it blocks, so the honest sentence is that none of it works at all, and the
+		// note has to name what is and is NOT affected: "ping does not work" sends an
+		// operator hunting a fault, and the difference between raw ESP and IPsec
+		// through NAT is the difference between "my VPN broke" and "my VPN is fine".
 		return note(netplane.UntunnelableBlock,
-			"Ping, traceroute, IPTV and VPN passthrough work only toward addresses your rules route "+
-				"directly — those already see your real IP address anyway. Toward addresses you send "+
-				"through the tunnel they will not work, because a tunnel cannot carry them and they "+
-				"would otherwise leak your real IP address.")
+			"Ping, traceroute, IPsec/PPTP VPN passthrough and IPTV do not work from your devices at "+
+				"all — not even toward addresses your rules route directly. None of this traffic can "+
+				"travel through a tunnel, so rather than let it out with your real IP address it is "+
+				"dropped. Concretely: ping and Windows tracert fail (on Linux and macOS traceroute "+
+				"sends UDP probes instead, which ARE tunnelled — the hops it prints are the tunnel's "+
+				"path, not your own), and so do raw IPsec (ESP/AH) and PPTP/GRE — a PPTP session will "+
+				"even look connected, because its control channel is TCP and only the payload is "+
+				"dropped. VPNs that run over UDP are NOT affected: WireGuard, OpenVPN-UDP and IPsec "+
+				"through NAT (IKE on UDP 500, NAT-T on UDP 4500) keep working normally. Multicast "+
+				"IPTV does not cross this router under any setting; that one is not this policy.")
 	}
 }
 

shater/apply/warnings_test.go

@@ -17,7 +17,7 @@ import (
 func TestCollectWarningsAttributesEntities(t *testing.T) {
 	got := collectWarnings(blockGlobals(),
 		[]string{
-			`ruleset "ads": remote list "https://x/y.srs" is UNREACHABLE right now, so it is NOT applied`,
+			ruleSetNotApplied,
 			`device "kids-tablet": no current IP (ip unset and MAC "aa:bb" not leased), skipped`,
 			`chain "hop": has no hops, target skipped`,
 			`dns_filter enabled but no resolvers configured; filter inert`,
@@ -38,15 +38,24 @@ func TestCollectWarningsAttributesEntities(t *testing.T) {
 		if w.Severity != SeverityCritical {
 			t.Errorf("an unapplied blocklist is a protection gap; severity = %q, want critical", w.Severity)
 		}
-		if strings.Contains(w.Message, `ruleset "ads":`) {
-			t.Errorf("the entity prefix must move into Section/Name, not stay in Message: %q", w.Message)
+		// The RULESET-NOT-APPLIED tag stays in the message on purpose: generate
+		// documents it as the operator's grep handle into logread.
+		if !strings.HasPrefix(w.Message, "RULESET-NOT-APPLIED:") {
+			t.Errorf("a tagged warning must keep its greppable tag in the message: %q", w.Message)
 		}
 	}
 	if w, ok := byName["device/kids-tablet"]; !ok {
 		t.Errorf("device warning not attributed; got %+v", got)
-	} else if w.Severity != SeverityWarning {
+	} else {
+		if w.Severity != SeverityWarning {
 			t.Errorf("a skipped device is not a protection gap; severity = %q, want warning", w.Severity)
 		}
+		// The plain `kind "name": message` prefix, by contrast, MOVES into
+		// Section/Name — it carries no information the fields do not.
+		if strings.Contains(w.Message, `device "kids-tablet":`) {
+			t.Errorf("the entity prefix must move into Section/Name, not stay in Message: %q", w.Message)
+		}
+	}
 	if w, ok := byName["chain/hop"]; !ok || w.Severity != SeverityWarning {
 		t.Errorf("chain warning: got %+v", w)
 	}
@@ -115,7 +124,7 @@ func TestCollectWarningsCapKeepsCriticals(t *testing.T) {
 	for i := 0; i < 200; i++ {
 		noisy = append(noisy, `chain "c": has no hops, target skipped`)
 	}
-	noisy = append(noisy, `ruleset "ads": remote list is UNREACHABLE right now, so it is NOT applied`)
+	noisy = append(noisy, ruleSetNotApplied)
 
 	got := collectWarnings(blockGlobals(), noisy, nil, nil)
 	if len(got) != maxStatusWarnings {
@@ -232,6 +241,170 @@ func TestWarningsAgainstRealGenerateOutput(t *testing.T) {
 	}
 }
 
+// ruleSetNotApplied is the message generate/ruleset.go:997 actually produces when
+// a remote blocklist cannot be fetched — the single most common real fault on a
+// router in Russia, and the one the panel has no other way to show (an omitted
+// rule-set produces no row in GET /api/ruleset/status, so the UI is
+// indistinguishable from "not configured").
+//
+// Quoted verbatim, tag and all, because the classifier is a heuristic over free
+// text and a test written against invented text proves nothing about it. The
+// version this replaced asserted on `... is UNREACHABLE ... is NOT applied`, a
+// sentence no producer has ever emitted; it passed for as long as the real
+// sentence was being graded a plain `warning` under section "generate" with no
+// name at all.
+const ruleSetNotApplied = `RULESET-NOT-APPLIED: ruleset "ads" is configured but NOT ACTIVE: ` +
+	`its source "https://big.oisd.nl/domainswild" is unreachable right now, so rule-set "ads" was ` +
+	`omitted and matches NOTHING until it loads (a blocklist blocks nothing; a routing rule is skipped). ` +
+	`Handing an unusable list to the engine would abort engine start and take the LAN down instead. ` +
+	`Retried automatically on the next reconcile (~1 min) — no action needed unless this persists.`
+
+// TestClassifyRealGenerateTexts grades the sentences generate REALLY emits, by
+// consequence.
+//
+// The defect this pins: severity was inverted. A blocklist that could not be
+// downloaded — protection the operator configured, not in force — came out
+// `warning`, because its tag broke the entity regexp and its wording matched no
+// marker. A typo in the same list's URL came out `critical`, because that one
+// parsed cleanly into section "ruleset". The panel's alarm banner lights on
+// critical and on nothing else, so the router shouted about the typo and stayed
+// quiet about the outage.
+func TestClassifyRealGenerateTexts(t *testing.T) {
+	cases := []struct {
+		name string
+		text string
+		want string
+		// section/entity attribution, when the panel must be able to deep-link.
+		section, entity string
+	}{{
+		name:    "remote blocklist could not be fetched",
+		text:    ruleSetNotApplied,
+		want:    SeverityCritical,
+		section: "ruleset", entity: "ads",
+	}, {
+		name: "not one DNS filter list could be built",
+		text: "DNS-FILTER-NOT-APPLIED: dns_filter is ON and lists are enabled, but NOT ONE of them " +
+			"could be built right now — nothing is being filtered or allowed. See the per-list " +
+			"warnings above for why. Rebuilt on the next reconcile (~1 min).",
+		want:    SeverityCritical,
+		section: "generate",
+	}, {
+		// generate/ruleset.go:1214 — the counterpart the outage used to be graded
+		// BELOW. It stays critical: the consequence is identical (the list is not
+		// loaded and matches nothing), which is the whole point — the inversion is
+		// fixed by lifting the outage, not by lowering the typo.
+		name:    "url blocklist with an empty url",
+		text:    `ruleset "ads": url source with empty url, skipped`,
+		want:    SeverityCritical,
+		section: "ruleset", entity: "ads",
+	}, {
+		// generate/ruleset.go:819 — the list IS still in force, from the copy
+		// compiled earlier. Grading this critical would light the alarm banner on
+		// most reconciles of a healthy router behind a flaky link, and a banner that
+		// is always on is a banner nobody reads when it finally matters.
+		name: "blocklist refresh failed but the compiled copy still blocks",
+		text: `ruleset "ads": could not refresh the list from "https://big.oisd.nl/domainswild" ` +
+			`(dial tcp: i/o timeout); continuing with the copy compiled earlier. Retried on the next reconcile.`,
+		want:    SeverityWarning,
+		section: "ruleset", entity: "ads",
+	}, {
+		// generate/route.go:407 — a rule the operator scoped to one device now
+		// applies to the entire network. Whatever it does, it now does to everyone.
+		name: "a rule's source scope collapsed to the whole LAN",
+		text: `rule "kids": none of its source entries can be matched by the engine (interface/zone/MAC ` +
+			`selectors and invalid addresses are dropped), so the rule now applies to EVERY client on ` +
+			`the router instead of that source — check it is still what you want, and use IP ` +
+			`addresses/subnets as the source`,
+		want:    SeverityCritical,
+		section: "rule", entity: "kids",
+	}, {
+		// generate/route.go:115 — the rule exists in the UI and routes nothing.
+		name: "a rule whose target is never reached",
+		text: `rule "work": no matcher the engine can evaluate, skipped — its target "group:auto" ` +
+			`never applies and the traffic follows the rules below it and the default`,
+		want:    SeverityCritical,
+		section: "rule", entity: "work",
+	}, {
+		// generate/ruleset.go:445 — a redundant field on a list that loads fine.
+		name:    "a redundant field on a working blocklist",
+		text:    `ruleset "ads": format "binary" is IGNORED for source=geosite — the category decides. Remove it to avoid confusion.`,
+		want:    SeverityWarning,
+		section: "ruleset", entity: "ads",
+	}, {
+		// generate/chain.go:108 — a configured path that does not resolve. Its
+		// traffic is blocked fail-closed, so no protection claim is broken.
+		name:    "a chain with no hops",
+		text:    `chain "hop": has no hops, target skipped`,
+		want:    SeverityWarning,
+		section: "chain", entity: "hop",
+	}, {
+		// generate/cache.go:92 — operational, the lists still compile.
+		name: "the compiled lists moved to tmpfs",
+		text: "cache: only 3 MiB free on /overlay (need 8 MiB), using tmpfs /tmp/shater instead — " +
+			"remote rule-sets will be re-downloaded after every reboot, so free some space",
+		want:    SeverityInfo,
+		section: "generate",
+	}}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			var got *Warning
+			for _, w := range collectWarnings(blockGlobals(), []string{tc.text}, nil, nil) {
+				if w.Section == "untunnelable" {
+					continue // the always-present policy notice
+				}
+				w := w
+				got = &w
+			}
+			if got == nil {
+				t.Fatalf("the warning was dropped entirely")
+			}
+			if got.Severity != tc.want {
+				t.Errorf("severity = %q, want %q\n  text: %s", got.Severity, tc.want, tc.text)
+			}
+			if got.Section != tc.section || got.Name != tc.entity {
+				t.Errorf("attribution = %q/%q, want %q/%q — the panel deep-links on these",
+					got.Section, got.Name, tc.section, tc.entity)
+			}
+		})
+	}
+}
+
+// TestUnreachableRuleSetFromRealGenerate drives the ACTUAL producer, so this stays
+// correct if generate rewords or re-tags the message. A url rule-set pointing at a
+// closed local port fails the reachability probe exactly the way an unreachable
+// public blocklist does, with no network needed.
+func TestUnreachableRuleSetFromRealGenerate(t *testing.T) {
+	m := holdModel("closed")
+	m.Rulesets = []model.Ruleset{
+		{Name: "ads", Type: "domain", Source: "url", URL: "http://127.0.0.1:1/blocklist.srs", Format: "binary"},
+	}
+	m.Rules = []model.Rule{
+		{Name: "blockads", Enabled: true, Order: 10, DstRuleset: []string{"ads"}, Target: "block"},
+	}
+
+	_, genWarnings, err := generate.GenerateWithWarnings(m)
+	if err != nil {
+		t.Fatalf("GenerateWithWarnings: %v", err)
+	}
+	t.Logf("real generate warnings: %q", genWarnings)
+
+	var found *Warning
+	for _, w := range collectWarnings(blockGlobals(), genWarnings, nil, nil) {
+		if w.Section == "ruleset" && w.Name == "ads" {
+			w := w
+			found = &w
+		}
+	}
+	if found == nil {
+		t.Fatalf("an unfetchable blocklist produced no warning attributed to it: %q", genWarnings)
+	}
+	if found.Severity != SeverityCritical {
+		t.Errorf("a blocklist that did not load is a protection gap the operator cannot otherwise "+
+			"see; severity = %q, want critical (message: %q)", found.Severity, found.Message)
+	}
+}
+
 // blockGlobals is the default policy fixture: kill-switch closed, untunnelable
 // traffic blocked — i.e. what a stock install runs.
 func blockGlobals() model.Globals {

shater/cmd/shaterd/main.go

@@ -329,6 +329,13 @@ func cmdRun() int {
 	if addr, ok := panelAddr(globals); ok {
 		panelSrv = panel.NewServer(applier, panel.Options{Addr: addr, Logger: logger})
 		panelSrv.SetStats(statsAgg)
+		// The log download reads the sink's FILE, and the sink writes to it from
+		// its own goroutine — so without a barrier a download can miss the last
+		// milliseconds of lines, which are the ones the operator came for. Hand
+		// the panel the barrier only (not the sink): it is a consumer of the log,
+		// not its owner. Bounded on the panel side, so a stuck writer cannot turn
+		// /api/log into the hang the async sink was built to prevent.
+		panelSrv.SetLogSync(sink.Sync)
 		go func() {
 			if err := panelSrv.Start(); err != nil && err != http.ErrServerClosed {
 				logger.Warn("panel server unavailable (daemon continues): ", err)

shater/cmd/shaterd/statsholder.go

@@ -33,8 +33,47 @@ var newStatsStore = stats.NewStore
 var _ stats.StatsStore = (*statsHolder)(nil)
 
 // statsHolder delegates every StatsStore call to the store currently installed.
-// Reads take a read lock so a swap never blocks concurrent panel queries for
-// longer than the pointer exchange.
+//
+// The read lock is held for the WHOLE delegated call, not just long enough to
+// pick the pointer up. That distinction is the entire safety property of this
+// type, and getting it wrong is invisible in every test that does not race a
+// reader against a swap:
+//
+//	// WRONG — this is what it used to do.
+//	func (h *statsHolder) get() stats.StatsStore {
+//	    h.mu.RLock(); defer h.mu.RUnlock(); return h.inner
+//	}
+//	func (h *statsHolder) Snapshot() stats.Snapshot { return h.get().Snapshot() }
+//
+// The lock is gone by the time Snapshot runs. A reader that has just taken the
+// pointer is holding nothing: the swap acquires the write lock unopposed, closes
+// that very store, and the reader then queries a closed one. For the persistent
+// backend that is not an error the panel can see — a closed bolt ring answers
+// every read with errRingUnavailable, i.e. an EMPTY PAGE, which the panel renders
+// as "you have no traffic". A lie, presented as data, from the one component
+// whose whole job is to report what is happening.
+//
+// Ordering the close correctly (see Reconfigure) protects the FILE. It cannot
+// protect a caller that already holds the pointer; only the lock can.
+//
+// The cost is bounded and lands where it should. Readers do not block each other
+// — RWMutex admits them all concurrently — so the panel's own load is unchanged.
+// What now waits is the SWAP: it must let the in-flight reads finish, which is
+// one page query (at most stats.MaxLogLimit rows) plus the old store's close. A
+// swap happens when a human changes a setting.
+//
+// The two alternatives were weighed and rejected:
+//
+//   - Reference-count the store and close it when the last reader leaves. It
+//     lets the swap return sooner, but it moves the close — flush, final bbolt
+//     commit, and any error it reports — onto whichever panel goroutine happens
+//     to drop the last reference. That is real lifecycle machinery, and error
+//     reporting from an arbitrary place, bought to avoid a wait measured in
+//     milliseconds on a once-per-Apply operation.
+//   - Make a closed store safe to read (serve its last snapshot). It cannot be
+//     done for the part that matters: the query and connection logs live in the
+//     bolt file, and a closed ring has nothing to serve but emptiness. That is
+//     the lie itself, not a defence against it.
 type statsHolder struct {
 	mu      sync.RWMutex
 	inner   stats.StatsStore
@@ -56,23 +95,60 @@ func newStatsHolder(eng *engine.Engine, logger log.ContextLogger, backend string
 	}
 }
 
-func (h *statsHolder) get() stats.StatsStore {
+// --- stats.StatsStore -------------------------------------------------------
+//
+// Every one of these runs the inner call INSIDE the read lock. There is
+// deliberately no `get()` accessor any more: a helper that hands the pointer out
+// is a helper that hands out an unguarded reference, and the whole defect above
+// was one such call site.
+
+func (h *statsHolder) Start() {
 	h.mu.RLock()
 	defer h.mu.RUnlock()
-	return h.inner
+	h.inner.Start()
 }
 
-// --- stats.StatsStore -------------------------------------------------------
+func (h *statsHolder) Close() error {
+	h.mu.RLock()
+	defer h.mu.RUnlock()
+	return h.inner.Close()
+}
 
-func (h *statsHolder) Start()       { h.get().Start() }
-func (h *statsHolder) Close() error { return h.get().Close() }
-func (h *statsHolder) Resubscribe() { h.get().Resubscribe() }
+func (h *statsHolder) Resubscribe() {
+	h.mu.RLock()
+	defer h.mu.RUnlock()
+	h.inner.Resubscribe()
+}
 
-func (h *statsHolder) Queries(q stats.LogQuery) []stats.LogEntry   { return h.get().Queries(q) }
-func (h *statsHolder) Conns(q stats.LogQuery) []stats.ConnLogEntry { return h.get().Conns(q) }
-func (h *statsHolder) QueriesPage(q stats.LogQuery) stats.LogPage  { return h.get().QueriesPage(q) }
-func (h *statsHolder) ConnsPage(q stats.LogQuery) stats.ConnPage   { return h.get().ConnsPage(q) }
-func (h *statsHolder) Snapshot() stats.Snapshot                    { return h.get().Snapshot() }
+func (h *statsHolder) Queries(q stats.LogQuery) []stats.LogEntry {
+	h.mu.RLock()
+	defer h.mu.RUnlock()
+	return h.inner.Queries(q)
+}
+
+func (h *statsHolder) Conns(q stats.LogQuery) []stats.ConnLogEntry {
+	h.mu.RLock()
+	defer h.mu.RUnlock()
+	return h.inner.Conns(q)
+}
+
+func (h *statsHolder) QueriesPage(q stats.LogQuery) stats.LogPage {
+	h.mu.RLock()
+	defer h.mu.RUnlock()
+	return h.inner.QueriesPage(q)
+}
+
+func (h *statsHolder) ConnsPage(q stats.LogQuery) stats.ConnPage {
+	h.mu.RLock()
+	defer h.mu.RUnlock()
+	return h.inner.ConnsPage(q)
+}
+
+func (h *statsHolder) Snapshot() stats.Snapshot {
+	h.mu.RLock()
+	defer h.mu.RUnlock()
+	return h.inner.Snapshot()
+}
 
 // --- swapping ---------------------------------------------------------------
 
@@ -90,17 +166,35 @@ func statsSpecFrom(g model.Globals) (string, stats.Config) {
 // Reconfigure swaps in a new store when backend/cfg differ from what is running.
 // It reports whether a swap happened.
 //
-// Ordering is deliberate: the NEW store is built and started BEFORE the old one
-// is closed, so a failure to construct it leaves the running store untouched and
-// stats keep working. The old store is then closed, which for the persistent
-// backend flushes the pending write buffer into its final bbolt commit — dropping
-// it without Close would lose the not-yet-committed tail of the log.
+// Ordering is deliberate, and it is the OPPOSITE of what it was: the old store is
+// CLOSED FIRST, and only then is the new one built.
+//
+// Building first looked safer — a construction failure would leave the running
+// store untouched — but the two stores of a persistent-backend swap resolve the
+// SAME on-disk path, and the second bbolt.Open there cannot win a file the first
+// one still holds. It sat on the flock for a second, timed out, and the old ring's
+// "an unopenable file must be a corrupt file" recovery deleted the live database
+// out from under its own writer (unlink of an open file succeeds on Linux, so
+// nothing complained): months of query log gone, replaced by an empty DB whose
+// Snapshot still reported the same backend. Changing ANY of the five stats knobs
+// was enough. The overlap was the whole defect, so the overlap is what had to go —
+// the classification bug is fixed alongside it in stats.newBoltRing, but a swap
+// that hands the file over cleanly does not depend on that fix being right.
+//
+// Closing first also flushes the old store's pending write buffer into its final
+// bbolt commit; dropping it without Close would lose the not-yet-committed tail.
+//
+// The whole exchange runs under the write lock, so a concurrent /api/stats poll
+// sees either the OLD OPEN store or the new one — never the closed one in between,
+// which would answer an honest-looking empty page. Readers pay one flush+commit of
+// blocking on a knob change; a torn read costs the panel its trust.
 //
 // stats.NewStore itself never returns nil and never panics: an unopenable stats
 // DB degrades to the in-memory ring internally and reports Backend "memory" from
 // Snapshot, so the panel shows what is actually running rather than what was
 // asked for. That is the "degrade, don't die" requirement, and it means
-// Reconfigure has no error path of its own.
+// Reconfigure has no error path of its own — and it is why closing first cannot
+// strand the daemon without a store.
 //
 // Log cursor continuity is DELIBERATELY not preserved across a swap. Each store
 // owns its own seq counter (memRing counts from zero; boltRing seeds from its own
@@ -112,12 +206,19 @@ func statsSpecFrom(g model.Globals) (string, stats.Config) {
 // honest Backend in the snapshot — which it gets for free by delegating.
 func (h *statsHolder) Reconfigure(backend string, cfg stats.Config) bool {
 	h.mu.Lock()
+	defer h.mu.Unlock()
 	if backend == h.backend && cfg == h.cfg {
-		h.mu.Unlock()
 		return false
 	}
 	old, oldBackend := h.inner, h.backend
 
+	// Hand the resources over BEFORE asking for them again: the old store releases
+	// its DB file (and its subscriptions) here, so the new one opens a path nobody
+	// holds. See the ordering note above — this line is the fix.
+	if err := old.Close(); err != nil {
+		h.log.Warn("stats: closing the previous ", oldBackend, " store: ", err)
+	}
+
 	next := newStatsStore(backend, h.eng, h.log, cfg)
 	next.Start()
 	// Point the fresh store at the running box's event managers. Start() subscribes,
@@ -130,13 +231,7 @@ func (h *statsHolder) Reconfigure(backend string, cfg stats.Config) bool {
 	h.inner = next
 	h.backend = backend
 	h.cfg = cfg
-	h.mu.Unlock()
 
-	// Close the old store OUTSIDE the lock: a persistent-store Close flushes and
-	// commits, which can take a moment, and no panel read should block behind it.
-	if err := old.Close(); err != nil {
-		h.log.Warn("stats: closing the previous ", oldBackend, " store: ", err)
-	}
 	h.log.Info("stats: backend ", oldBackend, " -> ", backend,
 		" (log cursors restart; reload the panel to resume live tailing)")
 	return true

shater/cmd/shaterd/statsholder_test.go

@@ -1,8 +1,10 @@
 package main
 
 import (
+	"sync"
 	"sync/atomic"
 	"testing"
+	"time"
 
 	"github.com/sagernet/sing-box/log"
 	"github.com/sagernet/sing-box/shater/engine"
@@ -150,3 +152,234 @@ func TestStatsHolderDelegatesAfterSwap(t *testing.T) {
 		t.Errorf("Close: %v", err)
 	}
 }
+
+// orderedStore is a fakeStore that timestamps its construction and its Close against a
+// shared step counter, so a test can assert the ORDER of the swap choreography rather
+// than only its outcome.
+type orderedStore struct {
+	fakeStore
+	step     *atomic.Int32
+	builtAt  int32
+	closedAt int32
+}
+
+func (o *orderedStore) Close() error {
+	o.closedAt = o.step.Add(1)
+	return nil
+}
+
+// TestStatsHolderClosesOldBeforeOpeningNew is the data-loss regression: changing ANY of
+// the five stats knobs used to destroy the persistent log.
+//
+// The swap built the replacement store BEFORE closing the one it replaced, and both
+// halves resolve the SAME on-disk DB path (stats.statsFilePath). The second bbolt.Open
+// therefore lost the flock race against a database that was still open, timed out after a
+// second, and the ring's "an unopenable file must be a corrupt file" recovery deleted it —
+// on Linux, unlinking an open file succeeds, so the old store went on writing into a
+// nameless inode while the panel was told nothing had changed. Months of query log, gone,
+// for a ring-size edit.
+//
+// The store the holder builds in production owns an exclusive resource, so the ONLY safe
+// order is release-then-acquire. That is what is pinned here; the constructor seam makes
+// it assertable without standing up a real DB.
+func TestStatsHolderClosesOldBeforeOpeningNew(t *testing.T) {
+	var step atomic.Int32
+	var built []*orderedStore
+	orig := newStatsStore
+	newStatsStore = func(backend string, _ *engine.Engine, _ log.ContextLogger, cfg ...stats.Config) stats.StatsStore {
+		s := &orderedStore{step: &step}
+		s.backend = backend
+		if len(cfg) > 0 {
+			s.cfg = cfg[0]
+		}
+		s.builtAt = step.Add(1)
+		built = append(built, s)
+		return s
+	}
+	t.Cleanup(func() { newStatsStore = orig })
+
+	h := newStatsHolderFrom(nil, log.StdLogger(), globalsWith("sqlite", 200))
+	h.Start()
+	if !h.ReconfigureFrom(globalsWith("sqlite", 5000)) {
+		t.Fatalf("changing the ring size must swap the store")
+	}
+	if len(built) != 2 {
+		t.Fatalf("built %d stores, want 2", len(built))
+	}
+	old, next := built[0], built[1]
+
+	if old.closedAt == 0 {
+		t.Fatal("the replaced store was never closed — its buffered rows are lost and its DB file stays locked")
+	}
+	if old.closedAt > next.builtAt {
+		t.Fatalf("the new store was constructed at step %d while the old one was still open (closed at step %d): "+
+			"both resolve the same stats DB path, so the second open loses the flock race and the loser's "+
+			"recovery path deletes the live database", next.builtAt, old.closedAt)
+	}
+}
+
+// TestStatsHolderReadsNeverSeeTheClosedStore is the second half of the swap defect,
+// and it is about the READER rather than the file.
+//
+// Closing the outgoing store before opening its replacement is what stops the DB file
+// from being deleted, but it does nothing for a caller that is already inside a call on
+// that store. The holder used to take the read lock only long enough to copy the pointer
+// out (`get()`), so the sequence below was ordinary, not exotic:
+//
+//  1. a panel poll takes the pointer to the running store and drops the lock;
+//  2. Reconfigure takes the write lock — unopposed, nobody is holding the read side —
+//     and closes that store;
+//  3. the poll now runs its query against a store that is shut.
+//
+// For the persistent backend step 3 is not a visible error: a closed bolt ring answers
+// every read with errRingUnavailable, which reaches the panel as an empty page and is
+// drawn as "no traffic". That is the same class of lie as everything else in this pass,
+// arriving from the other direction — the component whose entire job is to report what
+// happened, reporting that nothing did.
+//
+// The test drives the three steps EXPLICITLY rather than hoping a hammering loop lands in
+// the window (it did, about one run in five, which is exactly the kind of failure that
+// gets dismissed as a flake). The reader is parked inside the outgoing store's Snapshot;
+// the swap is then given every chance to close it underneath.
+func TestStatsHolderReadsNeverSeeTheClosedStore(t *testing.T) {
+	var stores []*gatedStore
+	orig := newStatsStore
+	newStatsStore = func(backend string, _ *engine.Engine, _ log.ContextLogger, cfg ...stats.Config) stats.StatsStore {
+		g := &gatedStore{entered: make(chan struct{}), release: make(chan struct{})}
+		g.backend = backend
+		if len(stores) > 0 {
+			close(g.release) // only the OUTGOING store parks its reader
+		}
+		stores = append(stores, g)
+		return g
+	}
+	t.Cleanup(func() { newStatsStore = orig })
+
+	h := newStatsHolderFrom(nil, log.StdLogger(), globalsWith("sqlite", 200))
+	h.Start()
+	outgoing := stores[0]
+
+	// 1. A panel poll is inside the outgoing store and cannot be hurried.
+	read := make(chan string, 1)
+	go func() { read <- h.Snapshot().Backend }()
+	select {
+	case <-outgoing.entered:
+	case <-time.After(10 * time.Second):
+		close(outgoing.release)
+		t.Fatal("the reader never reached the store")
+	}
+
+	// 2. The swap runs while that reader is still inside.
+	swapped := make(chan struct{})
+	go func() {
+		defer close(swapped)
+		h.ReconfigureFrom(globalsWith("sqlite", 5000))
+	}()
+
+	// Give it every opportunity to close the store out from under the parked reader.
+	// A correct holder cannot: the reader holds the read lock, so the swap is still
+	// waiting for the write lock when this deadline expires. A holder that only guards
+	// the pointer gets there in microseconds, and this loop ends the moment it does.
+	deadline := time.Now().Add(300 * time.Millisecond)
+	for !outgoing.shut.Load() && time.Now().Before(deadline) {
+		time.Sleep(time.Millisecond)
+	}
+
+	// 3. Let the poll finish and see what it was served.
+	close(outgoing.release)
+	got := <-read
+	select {
+	case <-swapped:
+	case <-time.After(10 * time.Second):
+		t.Fatal("the swap never completed after the reader left")
+	}
+
+	if got == closedStoreBackend {
+		t.Fatal("a panel read was served by the store that was being closed — an empty page presented as data")
+	}
+	if got != "sqlite" {
+		t.Fatalf("the read returned %q, want the running backend", got)
+	}
+	if len(stores) != 2 {
+		t.Fatalf("built %d stores, want 2", len(stores))
+	}
+	if !outgoing.shut.Load() {
+		t.Fatal("the outgoing store was never closed")
+	}
+	if got := h.Snapshot().Backend; got != "sqlite" {
+		t.Fatalf("after the swap Snapshot reports %q, want sqlite", got)
+	}
+}
+
+// closedStoreBackend is what gatedStore reports once it has been closed. No real store
+// says this; it exists so that a read served by a shut store is unmistakable instead of
+// merely empty — which is precisely what makes the real defect hard to see.
+const closedStoreBackend = "closed"
+
+// gatedStore parks the first caller of Snapshot until the test releases it, and reports
+// closedStoreBackend from the moment Close has run.
+type gatedStore struct {
+	fakeStore
+	entered   chan struct{}
+	release   chan struct{}
+	enterOnce sync.Once
+	shut      atomic.Bool
+}
+
+func (s *gatedStore) Close() error {
+	s.shut.Store(true)
+	return nil
+}
+
+func (s *gatedStore) Snapshot() stats.Snapshot {
+	s.enterOnce.Do(func() { close(s.entered) })
+	<-s.release
+	if s.shut.Load() {
+		return stats.Snapshot{Backend: closedStoreBackend}
+	}
+	return stats.Snapshot{Backend: s.backend}
+}
+
+// TestStatsHolderSwapWaitsForInFlightReads states the cost of the above out loud, so a
+// later reader of this file knows the wait is intended and not an oversight: a swap does
+// not begin while a read is in progress.
+func TestStatsHolderSwapWaitsForInFlightReads(t *testing.T) {
+	var stores []*gatedStore
+	orig := newStatsStore
+	newStatsStore = func(backend string, _ *engine.Engine, _ log.ContextLogger, cfg ...stats.Config) stats.StatsStore {
+		g := &gatedStore{entered: make(chan struct{}), release: make(chan struct{})}
+		g.backend = backend
+		if len(stores) > 0 {
+			close(g.release)
+		}
+		stores = append(stores, g)
+		return g
+	}
+	t.Cleanup(func() { newStatsStore = orig })
+
+	h := newStatsHolderFrom(nil, log.StdLogger(), globalsWith("sqlite", 200))
+	h.Start()
+	outgoing := stores[0]
+
+	go func() { _ = h.Snapshot() }()
+	<-outgoing.entered
+
+	swapped := make(chan struct{})
+	go func() {
+		defer close(swapped)
+		h.ReconfigureFrom(globalsWith("sqlite", 5000))
+	}()
+
+	select {
+	case <-swapped:
+		close(outgoing.release)
+		t.Fatal("the swap completed while a read was still inside the store it retired")
+	case <-time.After(200 * time.Millisecond):
+	}
+	close(outgoing.release)
+	select {
+	case <-swapped:
+	case <-time.After(10 * time.Second):
+		t.Fatal("the swap never completed after the read finished")
+	}
+}

shater/engine/engine.go

@@ -159,7 +159,21 @@ func New(logger ...log.ContextLogger) *Engine {
 	// URLTestHistory() below. The pointer is stable across Apply swaps, so health
 	// history survives config changes instead of being reset on every apply.
 	ctx = service.ContextWithPtr(ctx, urltest.NewHistoryStorage())
-	return &Engine{ctx: ctx, log: l}
+	// Pre-register the engine itself as the probe GATE, into the same shared
+	// registry and for the same reason as the two above: every urltest group
+	// built by every box.New reads it out of ctx (protocol/group/urltest.go), and
+	// the registration must survive Apply swaps because the question it answers
+	// outlives any single box.
+	//
+	// The gate answers "may this outbound run its own scheduled probe right
+	// now" — see Engine.ProbeAllowed. It is a live call, not a stored flag, so
+	// a chain hop that comes back resumes probing with no reapply. Registering
+	// the Engine here (rather than a snapshot) is what makes that possible;
+	// the struct is built first purely so ctx can point at it.
+	e := &Engine{log: l}
+	ctx = service.ContextWith[urltest.ProbeGate](ctx, e)
+	e.ctx = ctx
+	return e
 }
 
 // Apply installs opts as the running configuration.
@@ -200,9 +214,16 @@ func (e *Engine) applyLocked(opts option.Options) (bool, error) {
 	// change that flips a group used<->unused is then a real change that
 	// triggers a swap, and an unchanged config hashes identically on every
 	// reconcile because the stand-down is deterministic.
-	if stood := standDownUnusedSelfCheck(opts); stood > 0 && e.log != nil {
+	stood, used := standDownUnusedSelfCheck(opts)
+	if stood > 0 && e.log != nil {
 		e.log.Info("apply: stood down self-check on ", stood, " unused urltest group(s); the observatory is their only prober")
 	}
+	// Publish the same walk's used-set for ProbeWhenIdle BEFORE the new box is
+	// built, because the question is asked during that box's PostStart: a used
+	// group arms its probing ticker there rather than waiting for traffic. The
+	// observatory's own copy is published later, after a SUCCESSFUL swap, which
+	// is too late to be the answer.
+	e.publishKeepWarm(used)
 
 	newHash, err := e.hashOptions(opts)
 	if err != nil {

shater/engine/grouphealth.go

@@ -372,6 +372,17 @@ type ChainHealth struct {
 // SELECTED member's observation, or the freshest ALIVE member's when the
 // selection has no measurement of its own — the number shown must always be a
 // measurement somebody took, never an average nobody did.
+//
+// # The hop nobody reached: BlockedBy
+//
+// The prober walks a chain in wire order and stops at the first dead hop
+// (observatory.go probeChainOrdered), because a probe of hop 3 dials THROUGH
+// hop 2 and a hop 2 with no live member makes that probe a measurement of hop 2.
+// Everything behind the break is therefore not dialled at all, and this struct
+// says so: State is untested — no fresh knowledge, which is the truth — the
+// counters collapse into Untested, and BlockedBy names the hop that stopped the
+// walk. A row like that must never be read as a fault of its own; the fault is
+// at BlockedBy.Index, and that is the hop to go and fix.
 type ChainHopHealth struct {
 	Index      int    `json:"index"`       // 1-based position on the wire, L1..Ln
 	Tag        string `json:"tag"`         // "chain-<name>-h<i>" — the wrapper actually dialled
@@ -386,6 +397,24 @@ type ChainHopHealth struct {
 	Alive      int    `json:"alive"`
 	Dead       int    `json:"dead"`
 	Untested   int    `json:"untested"`
+	// BlockedBy is set ONLY on a hop the ordered walk never reached, and names the
+	// dead hop in front of it. Absent (omitted, never null) on every hop that was
+	// itself measured. When it is present State is always "untested" and the
+	// counters are always 0/0/0/Total — see the type comment.
+	BlockedBy *ChainHopBlock `json:"blocked_by,omitempty"`
+}
+
+// ChainHopBlock identifies the hop whose failure stopped a chain's ordered probe
+// walk: its 1-based wire index and the engine outbound tag that was dialled.
+//
+// The index is the field that matters — it is what the operator acts on, and it
+// lines up with ChainHopHealth.Index on the same chain, so a reader can point
+// straight at the offending row. The tag is diagnostic detail (logs, tooltips)
+// and is not a label to put in front of a person: "chain-ewan-wg-subs-h2" is not
+// a name anybody chose.
+type ChainHopBlock struct {
+	Index int    `json:"index"`
+	Tag   string `json:"tag"`
 }
 
 // ChainHealth reports the reachability (used/unused) of every named chain plus
@@ -481,9 +510,46 @@ func chainHopHealthOf(pool []adapter.Outbound, name string, view HealthView) []C
 		// internet. Marked after sorting so the flag cannot depend on pool order.
 		hops[len(hops)-1].Exit = true
 	}
+	markBlockedHops(hops)
 	return hops
 }
 
+// markBlockedHops applies the ordered walk's outcome to the projection: from the
+// first hop that reads DEAD, every later hop is rewritten as not-reached.
+//
+// This is a rewrite and not an annotation on purpose. The prober stops at the
+// first dead hop, so a hop behind the break has not been dialled since the break
+// appeared — but its board records do not vanish, they age out on the TTL. For
+// as long as that takes, the raw projection would keep publishing a verdict about
+// a hop nothing has attempted, and the most damaging version of that is a stale
+// "dead" pointing the operator at a hop that may be perfectly fine. Untested is
+// the honest reading of "nothing current is known", and BlockedBy is why.
+//
+// The counters collapse the same way, into Untested, so the invariants the whole
+// health surface promises still hold verbatim: Tested == Alive+Dead and
+// Alive+Dead+Untested == Total.
+//
+// Selected SURVIVES. It is not a measurement — it is the member the wrapper would
+// route through — and it stays true (and useful) whether or not anything reached
+// this hop.
+func markBlockedHops(hops []ChainHopHealth) {
+	for i := range hops {
+		if hops[i].State != HealthDead {
+			continue
+		}
+		blocker := &ChainHopBlock{Index: hops[i].Index, Tag: hops[i].Tag}
+		for j := i + 1; j < len(hops); j++ {
+			h := &hops[j]
+			h.State = HealthUntested
+			h.DelayMs, h.AgeSeconds = 0, -1
+			h.Alive, h.Dead, h.Tested = 0, 0, 0
+			h.Untested = h.Total
+			h.BlockedBy = blocker
+		}
+		return // the first break is the only one that can be observed
+	}
+}
+
 // chainNodeHop is the one-measurement hop: the wrapper itself was dialled by
 // the observatory, so its own board state IS the hop's health and the counters
 // degenerate to whichever bucket that state fills.

shater/engine/grouphealth_test.go

@@ -326,6 +326,10 @@ func TestChainHealthNilUsedSet(t *testing.T) {
 // the counters must obey the GroupHealth invariants on every hop, and the exit
 // flag must sit on the largest index. This is the "which hop died" question the
 // whole hop surface exists to answer.
+//
+// L3 additionally pins the ordered walk's half of the contract: it sits BEHIND
+// the dead L2, so whatever its stale board records say, it is reported untested
+// with L2 named — never as a hop of its own with a verdict nobody took.
 func TestChainHopHealthProjection(t *testing.T) {
 	hist := urltest.NewHistoryStorage()
 	now := time.Now()
@@ -396,16 +400,34 @@ func TestChainHopHealthProjection(t *testing.T) {
 		t.Errorf("h2 delay/age = %d/%d, want 0/3 (the selected member's failure observation)", h2.DelayMs, h2.AgeSeconds)
 	}
 
-	// L3: alive (one member answers), one member honestly untested — never
-	// folded into dead. The selected member is the alive one, so its numbers show.
-	if h3.Kind != "group" || h3.State != HealthAlive {
-		t.Fatalf("h3 = %+v, want an alive exit hop", h3)
+	// L3: BEHIND the break. Its board still holds an alive record for member "a"
+	// (probed before L2 died), but the prober has not dialled this hop since, so
+	// publishing that record would be a verdict nobody currently holds — and the
+	// symmetric case, a stale FAILURE, would send the operator to fix a hop that
+	// is fine. It reads untested, counters collapsed into Untested, with L2 named.
+	if h3.Kind != "group" || h3.State != HealthUntested {
+		t.Fatalf("h3 = %+v, want an UNTESTED hop: the walk stopped at L2 and never dialled it", h3)
 	}
-	if h3.Total != 2 || h3.Tested != 1 || h3.Alive != 1 || h3.Dead != 0 || h3.Untested != 1 {
-		t.Errorf("h3 counters = %+v, want 1 alive / 1 untested", h3)
+	if h3.BlockedBy == nil {
+		t.Fatalf("h3 = %+v, want BlockedBy naming L2 — 'why is this empty' must be answered on the row", h3)
 	}
-	if h3.Selected != "a" || h3.DelayMs != 200 || h3.AgeSeconds != 7 {
-		t.Errorf("h3 = %+v, want selection a with its 200ms/7s", h3)
+	if h3.BlockedBy.Index != 2 || h3.BlockedBy.Tag != "chain-c-h2" {
+		t.Errorf("h3.BlockedBy = %+v, want the dead hop 2 / chain-c-h2", *h3.BlockedBy)
+	}
+	if h3.Total != 2 || h3.Tested != 0 || h3.Alive != 0 || h3.Dead != 0 || h3.Untested != 2 {
+		t.Errorf("h3 counters = %+v, want every member untested (nothing was measured at this hop)", h3)
+	}
+	if h3.DelayMs != 0 || h3.AgeSeconds != -1 {
+		t.Errorf("h3 delay/age = %d/%d, want 0/-1 — there is no observation to age", h3.DelayMs, h3.AgeSeconds)
+	}
+	// The selection is not a measurement: the wrapper really would route through
+	// "a", and that stays true whether or not anything reached this hop.
+	if h3.Selected != "a" {
+		t.Errorf("h3 Selected = %q, want a — a block hides measurements, not configuration", h3.Selected)
+	}
+	// Nothing in FRONT of the break may be touched by it.
+	if h1.BlockedBy != nil || h2.BlockedBy != nil {
+		t.Errorf("BlockedBy leaked onto a measured hop: h1=%+v h2=%+v", h1.BlockedBy, h2.BlockedBy)
 	}
 
 	// The invariants, on every hop, exactly as GroupHealth promises.

shater/engine/grouptest.go

@@ -109,6 +109,14 @@ const (
 	// the observatory probed the target's path after the button press and the
 	// path did not answer. An honest negative, not a missing measurement.
 	groupTestErrPathDead = "the observatory's probe through this path failed"
+	// groupTestErrChainBlockedFmt: a CHAIN whose exit was never dialled because
+	// an earlier hop was probed and did not answer. The prober walks a chain in
+	// order and stops at the first dead hop, so there is no end-to-end
+	// measurement to wait for and there never will be while that hop is down.
+	// Reported at once, naming the hop, instead of spending the full deadline to
+	// answer "not reached yet" about a path that is known to be broken — and
+	// naming it is the whole value: the operator's next action is at that hop.
+	groupTestErrChainBlockedFmt = "hop %d of this chain was probed and did not answer, so nothing reaches the exit through it — fix that hop first"
 )
 
 // GroupTestResult is one target's test outcome — a group's or a chain's (Group
@@ -168,6 +176,13 @@ type groupTestTarget struct {
 	name string
 	ob   adapter.Outbound
 	sel  func() string
+	// isChain marks a CHAIN target. A chain is the one target whose measurement
+	// can be legitimately absent while the target is known to be broken: the
+	// prober walks a chain in order and stops at the first dead hop, so a chain
+	// whose hop 2 died never has its exit dialled at all. Without this flag a run
+	// would sit out its whole deadline and then report "not reached yet" about a
+	// path it knows is down — see testOneTarget.
+	isChain bool
 }
 
 // chainTargetsFrom discovers each materialised chain in the running
@@ -212,7 +227,7 @@ func chainTargetsFrom(pool []adapter.Outbound) []groupTestTarget {
 		if !ok {
 			continue
 		}
-		t := groupTestTarget{name: name, ob: ob}
+		t := groupTestTarget{name: name, ob: ob, isChain: true}
 		if hop := chainLastGroupHop(byTag, name); hop != nil {
 			t.sel = func() string { return chainMemberName(hop.Now(), name) }
 		}
@@ -226,18 +241,38 @@ func chainTargetsFrom(pool []adapter.Outbound) []groupTestTarget {
 // "chain-<name>-h<digits>". Member copies ("…-h<i>-<member>") and non-chain tags
 // parse false.
 func parseChainExitTag(tag string) (string, bool) {
+	name, _, ok := parseChainHopTag(tag)
+	return name, ok
+}
+
+// parseChainHopTag is parseChainExitTag plus the number: it recovers the chain
+// NAME and the 1-based HOP INDEX from a hop wrapper tag "chain-<name>-h<digits>"
+// (generate/chain.go buildHopWrapper). Member copies ("…-h<i>-<member>") and
+// non-chain tags parse false.
+//
+// The index is what lets the probe plan ORDER a chain's measurements. A chain is
+// a series path — hop i is dialled through hops 1..i-1 — so the difference
+// between "this hop failed" and "the hop in front of it failed" is the whole
+// diagnosis, and it cannot be recovered from an unordered set of tags.
+//
+// The split takes the LAST "-h<digits>", so a chain literally named "a-h2" is
+// read as chain "a-h2" hop 1 rather than chain "a" hop 2 — the same documented
+// reserved-namespace edge case parseGroupCopyTag accepts, pinned by
+// TestParseChainExitTag.
+func parseChainHopTag(tag string) (name string, hop int, ok bool) {
 	rest, ok := strings.CutPrefix(tag, "chain-")
 	if !ok {
-		return "", false
+		return "", 0, false
 	}
 	i := strings.LastIndex(rest, "-h")
 	if i <= 0 {
-		return "", false
+		return "", 0, false
 	}
-	if _, ok := parseAllDigits(rest[i+2:]); !ok {
-		return "", false
+	hop, ok = parseAllDigits(rest[i+2:])
+	if !ok {
+		return "", 0, false
 	}
-	return rest[:i], true
+	return rest[:i], hop, true
 }
 
 // chainLastGroupHop finds the chain's LAST group hop — the wrapper selector
@@ -507,6 +542,18 @@ func (e *Engine) testOneTarget(t groupTestTarget, used map[string]bool, obsEnabl
 
 	deadline := time.Now().Add(groupTestWaitDeadline)
 	for {
+		// Asked BEFORE the board read, and only for a chain. The exit of a blocked
+		// chain does carry a fresh dead verdict now — the observatory derives it
+		// from the broken hop (markChainExitDead) so selection cannot be tempted
+		// down a path that provably does not work — but "the probe through this
+		// path failed" would be the wrong sentence to show a person: no probe of
+		// the exit ran, and the actionable fact is WHICH hop stopped it. Same
+		// verdict, better answer.
+		if idx, ok := e.blockedChainHop(t, since); ok {
+			res.OK = false
+			res.Error = fmt.Sprintf(groupTestErrChainBlockedFmt, idx)
+			return res
+		}
 		if e.readFreshObservation(&res, t, since) {
 			if res.OK {
 				// The exit address is best-effort by design: see GroupTestResult.
@@ -524,6 +571,57 @@ func (e *Engine) testOneTarget(t groupTestTarget, used map[string]bool, obsEnabl
 	}
 }
 
+// blockedChainHop reports the hop that stopped this CHAIN target's ordered walk
+// before its exit, and only when the finding is FRESH enough to answer this run.
+//
+// Both halves matter. The projection (chainHopHealthOf) already computes the
+// break exactly once, and reading it here rather than re-deriving it keeps the
+// run and the Targets card from ever naming different hops. And the freshness
+// check is the same watermark readFreshObservation uses: a run rewinds the
+// observatory and then reports what it measures AFTERWARDS, so a break left over
+// from before the button press must not short-circuit the wait — the forced pass
+// may be about to find that hop alive again.
+//
+// Non-chain targets, unmaterialised chains and chains with no break all report
+// false, and the caller goes on waiting exactly as before.
+func (e *Engine) blockedChainHop(t groupTestTarget, since time.Time) (int, bool) {
+	if !t.isChain {
+		return 0, false
+	}
+	return blockingHopOf(chainHopHealthOf(e.runningPool(), t.name, e.HealthView()), time.Now(), since)
+}
+
+// blockingHopOf is the decision itself, split out so it is testable without a
+// box: given one chain's hop readout, the hop whose failure kept the EXIT from
+// being dialled, and only when that failure was observed at or after since.
+//
+// The exit's own BlockedBy is what is consulted, not "any dead hop": a chain
+// whose exit was itself probed and failed has a real end-to-end measurement, and
+// that measurement is the honest answer (groupTestErrPathDead). Only when the
+// exit was never reached is there nothing to wait for.
+func blockingHopOf(hops []ChainHopHealth, now, since time.Time) (int, bool) {
+	if len(hops) == 0 {
+		return 0, false
+	}
+	blocker := hops[len(hops)-1].BlockedBy
+	if blocker == nil {
+		return 0, false
+	}
+	for _, h := range hops {
+		if h.Index != blocker.Index {
+			continue
+		}
+		if h.AgeSeconds < 0 {
+			return 0, false
+		}
+		if now.Add(-time.Duration(h.AgeSeconds) * time.Second).Before(since) {
+			return 0, false // a break observed before this run started; keep waiting
+		}
+		return h.Index, true
+	}
+	return 0, false
+}
+
 // measuredTagOf is the tag the observatory actually probes for this target's
 // dial path — the tag whose board entry answers "how is this target doing":
 //

shater/engine/grouptest_test.go

@@ -587,3 +587,57 @@ func TestGroupTestScopeDedupedAndSorted(t *testing.T) {
 		t.Fatalf("scope = %v, want [alpha zeta]", scope)
 	}
 }
+
+// A manual run against a chain whose walk is blocked must say so, at once and by
+// hop number. The prober stops at the first dead hop, so such a chain's exit is
+// never dialled and no end-to-end observation is ever coming: waiting for one
+// would burn the full 120s deadline and then answer "the observatory has not
+// reached this target yet" — which reads like a timing artefact about a chain
+// that is, in fact, down and whose broken hop is already known.
+//
+// The freshness rule is the same one readFreshObservation uses: a run rewinds
+// the observatory and reports what it measures AFTERWARDS, so a break left over
+// from before the button press must not short-circuit the wait — the forced pass
+// may be about to find that hop alive again.
+func TestBlockingHopOfChainWalk(t *testing.T) {
+	since := time.Now()
+	// A 3-hop readout as the projection builds it: hop 2 dead, hop 3 not reached.
+	blocked := func(ageOfBreak int64) []ChainHopHealth {
+		blocker := &ChainHopBlock{Index: 2, Tag: "chain-c-h2"}
+		return []ChainHopHealth{
+			{Index: 1, Tag: "chain-c-h1", State: HealthAlive, AgeSeconds: 1},
+			{Index: 2, Tag: "chain-c-h2", State: HealthDead, AgeSeconds: ageOfBreak},
+			{Index: 3, Tag: "chain-c-h3", State: HealthUntested, AgeSeconds: -1, Exit: true, BlockedBy: blocker},
+		}
+	}
+
+	// Measured after the run started: answer now, naming hop 2.
+	if idx, ok := blockingHopOf(blocked(0), since.Add(time.Second), since); !ok || idx != 2 {
+		t.Errorf("fresh break = (%d,%v), want (2,true) — the run must name the hop instead of timing out", idx, ok)
+	}
+
+	// Measured BEFORE the run started: keep waiting. The forced pass has not
+	// re-probed that hop yet, and it may be about to answer.
+	if idx, ok := blockingHopOf(blocked(30), since.Add(time.Second), since); ok {
+		t.Errorf("stale break reported as this run's finding (hop %d); a run answers with what IT measured", idx)
+	}
+
+	// A chain whose exit WAS reached has a real end-to-end reading; the ordinary
+	// path reports it (alive, or groupTestErrPathDead). Nothing to short-circuit.
+	reached := []ChainHopHealth{
+		{Index: 1, Tag: "chain-c-h1", State: HealthAlive, AgeSeconds: 1},
+		{Index: 2, Tag: "chain-c-h2", State: HealthDead, AgeSeconds: 0, Exit: true},
+	}
+	if _, ok := blockingHopOf(reached, since.Add(time.Second), since); ok {
+		t.Error("a dead EXIT was reported as a block; its own probe is the answer")
+	}
+	if _, ok := blockingHopOf(nil, since, since); ok {
+		t.Error("an unmaterialised chain reported a block")
+	}
+
+	// A non-chain target never consults any of this.
+	e := New()
+	if _, ok := e.blockedChainHop(groupTestTarget{name: "auto"}, since); ok {
+		t.Error("a GROUP target was treated as a blocked chain")
+	}
+}

shater/engine/observatory.go

@@ -2,6 +2,7 @@ package engine
 
 import (
 	"context"
+	"sort"
 	"sync"
 	"time"
 
@@ -23,12 +24,40 @@ import (
 // MarkFailed. The strategies read the same board, so a death found here makes the
 // node unselectable immediately — no private overlay, no panel-only truth.
 //
-// It never replaces a group's own probing. An ACTIVE urltest group is its own
-// fast failure detector (failover switches on its 30s probe tick), and the
-// freshness gate below skips any tag whose newest observation is younger than the
-// global probe interval — which is precisely the set of tags an active group is
-// already keeping current. The observatory's budget lands on what nobody else
-// probes: idle groups' members, selector candidates, chain exits.
+// # ONE DIALLER PER TARGET
+//
+// It does not probe what a urltest group already probes — not "less often",
+// not at all. A urltest group dials its own members on its own ticker
+// (protocol/group/urltest.go testNodes), and for a chain's group hop that
+// checker is strictly the better instrument: each member copy carries the
+// previous hop as its Detour, so the group's probe travels the chain prefix by
+// construction, which is the path the traffic takes. Two probers on one target
+// is one measurement too many however carefully they take turns, so the plan
+// marks those measurements SelfChecked (probeplan.go) and this loop skips them.
+//
+// What is left is what no group covers, and it is the observatory's whole job:
+//
+//   - targets with no group behind them — a chain's NODE hop wrapper, the
+//     AmneziaWG endpoint at L1, a chain exit that is a plain outbound. Nothing
+//     else in the process will ever dial these;
+//   - members of a SELECTOR group, which has no checker at all
+//     (protocol/group/selector.go), and of a urltest group whose self-check was
+//     stood down;
+//   - egress-bound group copies, whose measurement carries the base-tag alias
+//     that feeds the per-node stats and that no group checker writes;
+//   - the GATE — who is allowed to dial at all (the used-set drives SelfCheck,
+//     the ordered walk drives ProbeAllowed) — and the reading of the board back
+//     out for the panel.
+//
+// The freshness gate below still skips any tag whose newest observation is
+// younger than the global probe interval, which now matters for the remaining
+// population rather than as the mechanism that kept two probers apart.
+//
+// The cost of the split: a used urltest group that carries no traffic runs its
+// warm-up sweep at box start and then, once its idle timeout expires, stops —
+// and the observatory no longer fills in behind it, so its members age out to
+// "untested". That is honest (nothing measured them) rather than wrong, and it
+// is the price of one dialler per target.
 //
 // # Schedule and cost
 //
@@ -41,6 +70,21 @@ import (
 // first pass starts IMMEDIATELY after an apply (cold boot: used paths validated
 // in seconds).
 //
+// # A chain is walked in order, and the walk stops at the first dead hop
+//
+// Most of the plan is independent measurements and is fired concurrently. A
+// CHAIN is not: hop i is dialled through hops 1..i-1, so a probe of hop 3 across
+// a hop 2 with no live member measures hop 2's failure and learns nothing about
+// hop 3. Each chain's jobs therefore run hop by hop (probeChainOrdered), and the
+// walk returns at the first hop the board reads dead — every hop behind it is
+// left undialled for that pass and reported untested with the blocker named,
+// which is both the honest answer and the cheap one.
+//
+// Nothing about a block is remembered. The gate is a fresh read of the health
+// board at every hop of every batch, and each cycle restarts at the top of the
+// plan, so the blocking hop is always re-probed and a recovery opens the rest of
+// the chain in the same pass.
+//
 // # Reconfiguration must not restart the walk
 //
 // ConfigureObservatory runs on every successful apply, and cron reconciles every
@@ -98,6 +142,36 @@ type observatoryState struct {
 	used   map[string]bool
 	cursor int
 	cycles uint64
+	// keepWarm is the set of tags the routing config REACHES, and it answers
+	// ProbeWhenIdle: a group in it keeps its own probing ticker running with no
+	// traffic flowing.
+	//
+	// It is deliberately NOT the same field as used above, even though both hold
+	// a used-set. used is published only after a SUCCESSFUL apply, because the
+	// panel's "unused" badge must describe the config that is actually running;
+	// this one is published BEFORE the new box is built, because a group asks the
+	// question during its own PostStart. A failed apply can therefore leave this
+	// describing a config that never started — worst case a group keeps a ticker
+	// it did not need until the next apply, which nobody can see and which costs
+	// one probe interval. Merging the two would force one of those two timings on
+	// the other, and each is right for its own reader.
+	keepWarm map[string]bool
+	// hops indexes the plan's chain measurements — chain name -> hops in wire
+	// order -> the dial tags measuring each hop. Rebuilt from the plan whenever
+	// the plan is, and read (never mutated) by a tick to decide whether a hop's
+	// jobs may run at all. Derived state, kept rather than recomputed per tick
+	// only because it is derived from something that changes once per apply.
+	hops chainPlanIndex
+	// probeFn overrides how ONE planned measurement is executed. nil — the
+	// production value — means probeJob: resolve the dial tag against the running
+	// box and dial it.
+	//
+	// It exists for one assertion that cannot be made any other way. The ordered
+	// walk's contract is that hops below a dead one are never DIALLED; the
+	// resulting health readout cannot prove that, because "not probed" and
+	// "probed, failed, then overridden" are the same untested row. Only counting
+	// attempts distinguishes them, so the tests substitute a counter here.
+	probeFn func(ProbeJob)
 	// busy guards against a slow tick overlapping the next one.
 	busy bool
 	// force is the ONE-SHOT "check now" flag raised by RefreshObservatory: while
@@ -127,7 +201,10 @@ func (e *Engine) ConfigureObservatory(cfg ObservatoryConfig) {
 	e.obs.interval = interval
 
 	if !cfg.Enabled {
-		e.obs.plan, e.obs.used, e.obs.cursor = nil, nil, 0
+		e.obs.plan, e.obs.used, e.obs.cursor, e.obs.hops = nil, nil, 0, nil
+		// The master switch is off: nothing probes in the background, so no group
+		// keeps a ticker alive on the background prober's behalf either.
+		e.obs.keepWarm = nil
 		e.obs.force = false
 		if e.obs.stop != nil {
 			close(e.obs.stop)
@@ -143,6 +220,10 @@ func (e *Engine) ConfigureObservatory(cfg ObservatoryConfig) {
 		e.obs.plan = jobs
 		e.obs.cursor = 0
 	}
+	// Derived from whichever plan is now installed — the kept one when the
+	// reconcile was a no-op, so the index can never describe a plan the cursor is
+	// not walking.
+	e.obs.hops = indexChainHops(e.obs.plan)
 
 	if e.obs.stop == nil {
 		stop, done := make(chan struct{}), make(chan struct{})
@@ -171,7 +252,8 @@ func (e *Engine) StopObservatory() {
 	stop, done := e.obs.stop, e.obs.done
 	e.obs.stop, e.obs.done, e.obs.nudge = nil, nil, nil
 	e.obs.enabled = false
-	e.obs.plan, e.obs.used, e.obs.cursor = nil, nil, 0
+	e.obs.plan, e.obs.used, e.obs.cursor, e.obs.hops = nil, nil, 0, nil
+	e.obs.keepWarm = nil
 	e.obs.force = false
 	if stop != nil {
 		close(stop)
@@ -214,6 +296,17 @@ func (e *Engine) RefreshObservatory() {
 	}
 }
 
+// setProbeFn installs a stand-in for the per-job dial (observatoryState.probeFn).
+// It exists for the tests: the ordered walk promises that hops behind a dead one
+// are never DIALLED, and only an attempt counter can show that — the health
+// readout afterwards looks the same whether a job was skipped or run and
+// discarded. Passing nil restores the production path.
+func (e *Engine) setProbeFn(f func(ProbeJob)) {
+	e.obsMu.Lock()
+	defer e.obsMu.Unlock()
+	e.obs.probeFn = f
+}
+
 // ObservatoryStatus reports whether the observatory is on, how many measurements
 // the current plan holds, and how many full passes have completed. Cheap; used by
 // tests and available for diagnostics.
@@ -314,6 +407,11 @@ func (e *Engine) observatoryTickOnce() {
 	batch := append([]ProbeJob(nil), e.obs.plan[start:end]...)
 	e.obs.cursor = end
 	interval := e.obs.interval
+	hops := e.obs.hops
+	probe := e.obs.probeFn
+	if probe == nil {
+		probe = e.probeJob
+	}
 	// A forced pass (RefreshObservatory) bypasses the freshness gate for its one
 	// walk of the plan. The flag is captured for THIS batch and cleared the
 	// moment the walk's last batch is scheduled: the remaining jobs of this very
@@ -350,8 +448,13 @@ func (e *Engine) observatoryTickOnce() {
 	now := time.Now()
 	sem := make(chan struct{}, observatoryConcurrency)
 	var wg sync.WaitGroup
-	for _, j := range batch {
-		if !force && !observatoryShouldProbe(hist, j, interval, now) {
+
+	// Two populations, two disciplines. A job that measures nothing on a chain is
+	// independent of every other job and runs as it always did: fire the lot,
+	// bounded by the semaphore. A chain's jobs are a SERIES and run hop by hop.
+	free, chains := splitChainBatch(batch)
+	for _, j := range free {
+		if j.SelfChecked || (!force && !observatoryShouldProbe(hist, j, interval, now)) {
 			continue
 		}
 		wg.Add(1)
@@ -359,12 +462,393 @@ func (e *Engine) observatoryTickOnce() {
 		go func(j ProbeJob) {
 			defer wg.Done()
 			defer func() { <-sem }()
-			e.probeJob(j)
+			probe(j)
 		}(j)
 	}
+	for _, walk := range chains {
+		wg.Add(1)
+		go func(walk chainBatch) {
+			defer wg.Done()
+			e.probeChainOrdered(walk, hops, hist, interval, now, force, sem, probe)
+		}(walk)
+	}
 	wg.Wait()
 }
 
+// probeChainOrdered runs one chain's share of a batch hop by hop, in wire order,
+// and RETURNS the moment a hop below a dead one comes up — leaving every
+// remaining job of that chain undialled for this pass.
+//
+// # Why the walk stops rather than filtering
+//
+// A chain is a series path: the plan's job for hop i dials through hops 1..i-1.
+// If hop 2 has no live member, the hop-3 probe fails INSIDE hop 2, learns nothing
+// about hop 3, and costs a full probe timeout to learn it. Recording that as
+// "hop 3 is dead" is the exact class of lie this codebase keeps removing: dead is
+// a positive finding about the thing that was probed, and hop 3 was never
+// reached. So the walk stops, the skipped hops keep no fresh observation, and
+// they surface as untested WITH the blocking hop named (grouphealth.go
+// ChainHopHealth.BlockedBy) rather than as faults of their own.
+//
+// # Why it cannot get stuck
+//
+// Nothing is remembered between passes. The gate is re-read from the health board
+// at every hop of every batch (blockedBefore), and the cursor rewinds to the top
+// of the plan each cycle, so the FIRST dead hop is always re-probed — it is never
+// itself below a break. The moment it answers again the gate opens and the rest
+// of the chain is probed in the same pass. There is no "blocked" flag anywhere to
+// clear, which is the point: a cached block would outlive the failure that caused
+// it.
+//
+// # Cost
+//
+// Hops within one batch are serialised, so a batch holding several hops of one
+// chain can take hops x probeTimeout instead of one probeTimeout. The busy guard
+// in observatoryTickOnce absorbs that (a slow tick makes the next a no-op), and
+// the case it exists for — a dead hop — now costs LESS than before, because
+// everything behind it is skipped entirely.
+func (e *Engine) probeChainOrdered(
+	walk chainBatch,
+	idx chainPlanIndex,
+	hist *urltest.HistoryStorage,
+	interval time.Duration,
+	now time.Time,
+	force bool,
+	sem chan struct{},
+	probe func(ProbeJob),
+) {
+	for _, hop := range walk.hops {
+		// Re-read the board here, not once up front: the hop before this one may
+		// have been probed moments ago by the loop's previous iteration, and its
+		// verdict is exactly what decides this one.
+		if blocker, blocked := idx.blockedBefore(walk.chain, hop.index, e.HealthView()); blocked {
+			e.markChainExitDead(walk.chain, idx, blocker)
+			return // hops are ascending, so everything left is behind the same break
+		}
+		var wg sync.WaitGroup
+		for _, j := range hop.jobs {
+			// A self-checked job is measured by its own group's checker, which is
+			// gated by ProbeAllowed on the same rule this loop applies. It is
+			// present here only so the hop shows up in the map the gate reads;
+			// dialling it would be the duplicate the flag exists to remove.
+			if j.SelfChecked || (!force && !observatoryShouldProbe(hist, j, interval, now)) {
+				continue
+			}
+			wg.Add(1)
+			sem <- struct{}{}
+			go func(j ProbeJob) {
+				defer wg.Done()
+				defer func() { <-sem }()
+				probe(j)
+			}(j)
+		}
+		// The hop's verdict is only complete when every member copy has answered,
+		// so the next hop's gate must not be read until they have.
+		wg.Wait()
+	}
+}
+
+// markChainExitDead records a DEAD verdict for a chain's EXIT on the shared
+// health board when the ordered walk stopped short of it.
+//
+// # Two questions, two answers, and why they differ
+//
+// "Is this hop's own node alive?" and "can this chain carry traffic?" are not the
+// same question, and behind a break they have different answers:
+//
+//   - the HOP's own health is genuinely UNKNOWN. Nothing dialled it, so its card
+//     reads untested with BlockedBy naming the blocker (markBlockedHops), and
+//     that stays exactly as it is;
+//   - the CHAIN's health is KNOWN, and the answer is no. A chain is a series
+//     path; hop k was probed and did not answer — a positive finding — and every
+//     dial through the chain crosses hop k. The exit cannot carry traffic. That
+//     is not absence of knowledge, it is a conclusion drawn from a measurement
+//     somebody took.
+//
+// # Why the board must say so
+//
+// The board is not only the panel's data source; the strategies select on it, and
+// they rank UNTESTED ABOVE DEAD on purpose (protocol/group/urltest_health_lx.go
+// selectExcluding: "an untested one is a better bet than a known-dead one"). So
+// leaving a provably-broken path untested is not a neutral silence — it is an
+// invitation to route traffic down it, which is worse than the mislabelling this
+// whole change set exists to remove. Marking it keeps
+// TestChainDeadExitMarkedByObservatory's older invariant intact too: a dead chain
+// is marked dead, and a dead entry stays distinguishable from a never-measured
+// one.
+//
+// # Why this is not a fabricated verdict
+//
+// Nothing here claims a probe happened. It records the CONSEQUENCE of a probe
+// that did happen, one hop earlier, and it is re-derived from the board every
+// pass — the instant the blocking hop answers again, the walk proceeds and the
+// exit's next verdict is a real measurement of its own. The flip is logged with
+// its cause so the trail never reads as an unexplained death.
+//
+// The exit's tags are the LAST hop's measurement tags: the wrapper itself for a
+// node exit, the member copies for a group exit — in both cases exactly what a
+// reader consults to ask whether the chain works.
+func (e *Engine) markChainExitDead(chain string, idx chainPlanIndex, blocker chainPlanHop) {
+	hops := idx[chain]
+	if len(hops) == 0 {
+		return
+	}
+	exit := hops[len(hops)-1]
+	if exit.index <= blocker.index {
+		return // the blocker IS the exit: its own probe already said so
+	}
+	hist := e.URLTestHistory()
+	if hist == nil {
+		return
+	}
+	ttl := e.healthTTL()
+	for _, tag := range exit.tags {
+		if e.log != nil && hist.Verdict(tag, ttl) != urltest.VerdictDead {
+			e.log.Info("observatory: ", tag, ": -> dead (chain hop ", blocker.index,
+				" was probed and did not answer, so nothing reaches the exit through it)")
+		}
+		hist.MarkFailed(tag)
+	}
+}
+
+// chainBatch is one chain's share of one batch, grouped into hops in wire order.
+type chainBatch struct {
+	chain string
+	hops  []chainBatchHop
+}
+
+// chainBatchHop is the jobs of ONE hop that fell inside the current batch. It is
+// a subset: a hop with more member copies than a batch holds is split across
+// consecutive batches, which is harmless — the gate is computed from the whole
+// plan (chainPlanIndex), never from what happens to be in hand.
+type chainBatchHop struct {
+	index int
+	jobs  []ProbeJob
+}
+
+// splitChainBatch separates a batch into the chain-less jobs and the per-chain
+// series. The plan is already sorted so a chain's jobs are contiguous and
+// ascending, but this does not rely on that: it groups explicitly and sorts each
+// chain's hops, so a batch that arrived out of order still runs in path order.
+func splitChainBatch(batch []ProbeJob) (free []ProbeJob, chains []chainBatch) {
+	at := map[string]int{}
+	for _, j := range batch {
+		if j.Chain == "" {
+			free = append(free, j)
+			continue
+		}
+		i, ok := at[j.Chain]
+		if !ok {
+			i = len(chains)
+			at[j.Chain] = i
+			chains = append(chains, chainBatch{chain: j.Chain})
+		}
+		c := &chains[i]
+		h := -1
+		for k := range c.hops {
+			if c.hops[k].index == j.Hop {
+				h = k
+				break
+			}
+		}
+		if h < 0 {
+			c.hops = append(c.hops, chainBatchHop{index: j.Hop})
+			h = len(c.hops) - 1
+		}
+		c.hops[h].jobs = append(c.hops[h].jobs, j)
+	}
+	for i := range chains {
+		hops := chains[i].hops
+		sort.Slice(hops, func(a, b int) bool { return hops[a].index < hops[b].index })
+	}
+	return free, chains
+}
+
+// chainPlanIndex is the whole plan's chain measurements: chain name -> hops in
+// wire order, each carrying every DIAL TAG that measures it.
+//
+// It is the gate's source of truth, and it must come from the PLAN rather than
+// from the running box, for the same reason probeJob resolves its dial tag at
+// dial time: the plan is what this pass is walking. A hop's verdict rolled up
+// from a set of tags the pass does not probe would gate the pass on somebody
+// else's measurements.
+type chainPlanIndex map[string][]chainPlanHop
+
+type chainPlanHop struct {
+	index int
+	tags  []string
+}
+
+// indexChainHops builds the index from a plan. nil for a plan with no chain in it
+// — the overwhelmingly common case, and a nil map answers every lookup with "no
+// hops, nothing blocks" at no cost.
+func indexChainHops(plan []ProbeJob) chainPlanIndex {
+	var out chainPlanIndex
+	for _, j := range plan {
+		if j.Chain == "" {
+			continue
+		}
+		if out == nil {
+			out = chainPlanIndex{}
+		}
+		hops := out[j.Chain]
+		at := -1
+		for k := range hops {
+			if hops[k].index == j.Hop {
+				at = k
+				break
+			}
+		}
+		if at < 0 {
+			hops = append(hops, chainPlanHop{index: j.Hop})
+			at = len(hops) - 1
+		}
+		hops[at].tags = append(hops[at].tags, j.Dial)
+		out[j.Chain] = hops
+	}
+	for name, hops := range out {
+		sort.Slice(hops, func(a, b int) bool { return hops[a].index < hops[b].index })
+		out[name] = hops
+	}
+	return out
+}
+
+// blockedBefore reports the LOWEST hop of chain, strictly before hop, that the
+// health board currently reads dead — the hop that stops the walk. Only a
+// positive dead finding blocks: an untested hop in front means nothing is known
+// yet, and refusing to probe on "nothing is known" would make a cold start
+// permanent.
+func (idx chainPlanIndex) blockedBefore(chain string, hop int, view HealthView) (chainPlanHop, bool) {
+	for _, h := range idx[chain] {
+		if h.index >= hop {
+			break
+		}
+		if hopBoardState(h.tags, view) == HealthDead {
+			return h, true
+		}
+	}
+	return chainPlanHop{}, false
+}
+
+// ProbeAllowed implements urltest.ProbeGate: it answers, for one outbound tag,
+// whether that outbound's OWN probing schedule may dial right now.
+//
+// # What it is for
+//
+// The observatory is not the only prober. A urltest group probes its own
+// members — a warm-up sweep at box start and a ticker while traffic touches it
+// — and a chain's GROUP HOP is materialised as exactly such a group
+// ("chain-<n>-h<i>", generate/chain.go). Every member of that group dials
+// through the hop in front of it, so when THAT hop is dead the group's sweep
+// spends one probe timeout per member to rediscover the same broken hop, and
+// files each result against a hop nothing reached. The projection already
+// refuses to publish those readings (markBlockedHops); this stops them being
+// taken.
+//
+// # Why this is not the SelfCheck flag
+//
+// standDownUnusedSelfCheck answers a different question — "does any enabled
+// rule reach this group at all" — decided once, written into the config that
+// reaches box.New, and true for the whole life of that box. A chain hop wrapper
+// IS reached by the rules and must keep its flag (TestStandDownNeverTouchesChainHopWrappers
+// pins that). This answers "is the path in front of it working AT THIS MOMENT",
+// which changes on its own and must therefore be asked, never stored. Merging
+// the two would either put a live question in a static flag or take a used
+// chain permanently off the board.
+//
+// # Why it cannot get stuck
+//
+// It holds nothing. Every call recomputes the block from the same plan index
+// and the same health board the observatory's own walk uses, so the moment the
+// blocking hop answers a probe this returns true again and the wrapper's next
+// tick dials normally. The blocking hop is itself never behind a break, so the
+// observatory re-probes it every cycle: there is always something re-asking the
+// question that produced the block.
+//
+// It answers TRUE whenever it does not know — no plan, observatory disabled,
+// not a chain hop tag, chain absent from the plan. Refusing on missing
+// information would silence probing exactly when least is known, and nothing
+// would ever measure its way back out.
+func (e *Engine) ProbeAllowed(tag string) bool {
+	chain, hop, ok := parseChainHopTag(tag)
+	if !ok {
+		return true // not a chain hop wrapper: nothing sits in front of it
+	}
+	e.obsMu.Lock()
+	enabled, idx := e.obs.enabled, e.obs.hops
+	e.obsMu.Unlock()
+	if !enabled || idx == nil {
+		return true
+	}
+	// HealthView takes obsMu itself (healthTTL), so it must be called with the
+	// lock released.
+	_, blocked := idx.blockedBefore(chain, hop, e.HealthView())
+	return !blocked
+}
+
+// ProbeWhenIdle implements urltest.ProbeGate: it reports whether an outbound
+// must keep measuring itself with no traffic flowing through it.
+//
+// TRUE for anything the routing configuration reaches. Such a group's health is
+// a live question at all times — a rule matching a narrow domain list is in
+// force whether or not it fired in the last half hour — and without this its own
+// ticker would retire on the idle timeout and NOTHING would replace it: the
+// observatory stands off a urltest group's members by design (ProbeJob.SelfChecked).
+// The panel would then report "untested" about an armed rule, and the first
+// request through it would pay a cold probe instead of picking a member already
+// known to work. Keeping the group's own ticker running restores exactly what
+// the observatory used to spend on those same targets, at the same interval, and
+// keeps it to ONE dialler.
+//
+// FALSE whenever nothing is known — no config applied yet, unknown tag, master
+// switch off. This method adds work rather than withholding it, so the direction
+// of "don't know" is the opposite of ProbeAllowed's: claiming keep-warm on
+// missing information would leave groups probing forever for no stated reason.
+//
+// It does NOT bypass any other refusal. A stood-down group never asks (the
+// group's own keepWarm short-circuits on selfCheckDisabled), and a kept-warm
+// group behind a dead hop still ticks WITHOUT dialling, because every tick goes
+// through scheduledCheck -> ProbeAllowed. Warm means measured on schedule, never
+// "hammering through a broken path".
+func (e *Engine) ProbeWhenIdle(tag string) bool {
+	e.obsMu.Lock()
+	defer e.obsMu.Unlock()
+	return e.obs.keepWarm[tag]
+}
+
+// publishKeepWarm installs the set ProbeWhenIdle answers from. Called from
+// applyLocked with the used-set of the config being applied, and cleared when
+// background probing is switched off — see the keepWarm field for why this is
+// published on a different schedule from the observatory's own used-set.
+func (e *Engine) publishKeepWarm(used map[string]bool) {
+	e.obsMu.Lock()
+	e.obs.keepWarm = used
+	e.obsMu.Unlock()
+}
+
+// hopBoardState rolls a hop's measurement tags into one verdict, by exactly the
+// rule chainGroupHop (grouphealth.go) uses for the same question — "can this hop
+// carry the chain": alive as soon as anything answers, dead only when something
+// was tested and nothing answers, untested when nothing was tested at all. The
+// prober and the panel must agree about which hop broke a chain, so this is that
+// rule written once more against tags instead of against a materialised group;
+// TestChainHopGateMatchesProjection pins the two together.
+func hopBoardState(tags []string, view HealthView) string {
+	tested := 0
+	for _, tag := range tags {
+		switch state, _, _ := view.State(tag); state {
+		case HealthAlive:
+			return HealthAlive
+		case HealthDead:
+			tested++
+		}
+	}
+	if tested > 0 {
+		return HealthDead
+	}
+	return HealthUntested
+}
+
 // observatoryShouldProbe is the freshness gate: a job runs when ANY tag it
 // covers has no observation at all, or its newest observation — success OR
 // failure — is older than the global probe interval.

shater/engine/probeplan.go

@@ -51,6 +51,28 @@ import (
 // ever being dialled by the observatory. Chain copies are recorded only under
 // themselves: a chain prefix is nobody else's path.
 //
+// # Who dials
+//
+// Reaching a target does not make it OURS to dial. A member of a urltest group
+// already has a prober — that group's own checker — and for a chain hop that
+// checker measures the better path: the member copy carries the previous hop as
+// its Detour, so its probe travels the chain prefix without anything having to
+// be arranged. Those measurements are emitted with SelfChecked set and the
+// observatory never dials them. What stays ours is what no group probes: node
+// hop wrappers, endpoints, selector members, stood-down groups' members, and
+// egress copies (whose base-tag alias no checker writes).
+//
+// # Order
+//
+// The plan is a LIST, not a set, and for a chain the order is load-bearing. Each
+// job that measures a chain carries the chain name and its 1-based hop index
+// (ProbeJob.Chain/Hop, threaded through the walk as planPos), and the emitted
+// plan is sorted so a chain's jobs come out grouped and ascending by hop. The
+// observatory walks them in that order and stops at the first dead hop —
+// probing hop 3 through a hop 2 with no live member measures hop 2's failure and
+// nothing else, so recording it against hop 3 names the wrong suspect and burns a
+// probe timeout doing it.
+//
 // # Dedup
 //
 // The probe URL is global (plan §5.D), so the dedup key is the dial path alone:
@@ -69,6 +91,42 @@ type ProbeJob struct {
 	Dial  string
 	URL   string
 	Store []string
+	// Chain and Hop place this measurement ON a chain's path: the chain NAME and
+	// the 1-based hop index it measures. Both zero ("" / 0) for every job that is
+	// not part of a chain, which is most of them.
+	//
+	// This is what makes the walk ORDERED (observatory.go). A chain is a series
+	// path, so the probe of hop 3 dials THROUGH hops 1 and 2; if hop 2 has no live
+	// member, that probe fails at hop 2 and says nothing whatsoever about hop 3.
+	// Recording it as a verdict about hop 3 was the defect: it pointed the
+	// operator at the wrong hop and spent a full probe timeout to do it. The
+	// prober therefore walks a chain h1 -> hN and stops at the first dead hop, and
+	// these two fields are the only thing that tells it which jobs form which hop
+	// of which path.
+	//
+	// A hop is usually SEVERAL jobs — a group hop's member copies are one
+	// measurement each — so Hop is a grouping key, never a job's identity.
+	Chain string
+	Hop   int
+	// SelfChecked marks a measurement whose target already has a dialler: it is a
+	// member of a URLTEST group, and that group's own checker probes exactly this
+	// outbound, on exactly this dial path, on the same global interval
+	// (protocol/group/urltest.go testNodes). The observatory therefore does NOT
+	// dial it. One target, one dialler.
+	//
+	// The group's checker is the RIGHT dialler for these, not merely an equal
+	// one: a chain hop member carries the Detour of the hop in front of it, so
+	// the checker's probe travels the chain prefix by construction, which is the
+	// path the traffic takes. Nothing had to be arranged for that to be true.
+	//
+	// The job STAYS in the plan rather than being dropped, because the plan is
+	// two things at once: the observatory's dial list AND the map of which tags
+	// measure which hop of which chain. The ordered walk's gate reads the second
+	// (indexChainHops -> blockedBefore), and it must see every measurement of a
+	// hop, not only the ones this prober performs — a hop whose members are all
+	// self-checked would otherwise vanish from the map and stop being able to
+	// block anything.
+	SelfChecked bool
 }
 
 // BuildObservatoryPlan derives the observatory's probe plan from the applied
@@ -81,7 +139,7 @@ type ProbeJob struct {
 // probeURL is the global probe URL; "" lets urltest fall back to its gstatic
 // default, exactly as the generator does.
 //
-// The result is deterministic (sorted by Dial) so a cursor walking it across
+// The result is deterministic (see probeJobLess) so a cursor walking it across
 // ticks is stable, and plansEqual can tell a no-op reconcile from real change.
 func BuildObservatoryPlan(opts option.Options, probeURL string) ([]ProbeJob, map[string]bool) {
 	w := &planWalk{
@@ -92,7 +150,9 @@ func BuildObservatoryPlan(opts option.Options, probeURL string) ([]ProbeJob, map
 		targets: map[string]*planTarget{},
 	}
 	for _, root := range planRoots(opts) {
-		w.visit(root)
+		// A root comes from a routing rule, not from a group, so nothing is
+		// checking it on our behalf.
+		w.visit(root, planPos{}, false)
 	}
 
 	jobs := make([]ProbeJob, 0, len(w.targets))
@@ -102,18 +162,49 @@ func BuildObservatoryPlan(opts option.Options, probeURL string) ([]ProbeJob, map
 			store = append(store, tag)
 		}
 		sort.Strings(store)
-		jobs = append(jobs, ProbeJob{Dial: t.dial, URL: probeURL, Store: store})
+		jobs = append(jobs, ProbeJob{
+			Dial: t.dial, URL: probeURL, Store: store,
+			Chain: t.pos.chain, Hop: t.pos.hop, SelfChecked: t.selfChecked,
+		})
 	}
-	sort.Slice(jobs, func(i, j int) bool { return jobs[i].Dial < jobs[j].Dial })
+	sort.Slice(jobs, func(i, j int) bool { return probeJobLess(jobs[i], jobs[j]) })
 	return jobs, w.used
 }
 
+// probeJobLess is the plan's order, and it is a CONTRACT rather than a
+// presentation detail: a chain's jobs come out grouped by chain and ascending by
+// hop, so a cursor walking the plan meets h1 before h2 before h3. The observatory
+// relies on that to stop at the first dead hop (see probeChainOrdered); a plan
+// sorted by dial tag alone would interleave the hops of one path and there would
+// be no "first" to stop at.
+//
+// Chain-less jobs (Chain "") sort first, among themselves by dial tag, exactly as
+// the whole plan used to. Ties inside one hop break on the dial tag, so the order
+// is total and two builds of one config are byte-identical — the property
+// ConfigureObservatory's cursor keeping depends on.
+func probeJobLess(a, b ProbeJob) bool {
+	if a.Chain != b.Chain {
+		return a.Chain < b.Chain
+	}
+	if a.Hop != b.Hop {
+		return a.Hop < b.Hop
+	}
+	return a.Dial < b.Dial
+}
+
 // planEntry is the slice of one configured outbound/endpoint the planner needs.
 type planEntry struct {
 	typ     string
 	group   bool     // selector/urltest — expanded, never dialled
 	members []string // group members, in config order
 	detour  string   // DialerOptions.Detour ("" when none)
+	// selfChecks is true for a group that PROBES ITS OWN MEMBERS: a urltest
+	// group whose self-check has not been stood down. A selector never does (it
+	// has no checker at all — protocol/group/selector.go), and a urltest group
+	// with SelfCheck=false has had its schedule taken away deliberately
+	// (standDownUnusedSelfCheck), so in both of those cases the observatory is
+	// the only possible dialler and must remain one.
+	selfChecks bool
 }
 
 // planIndex flattens opts into tag -> planEntry. Endpoints (wireguard/AmneziaWG)
@@ -127,6 +218,7 @@ func planIndex(opts option.Options) map[string]planEntry {
 			group:      ob.Type == C.TypeSelector || ob.Type == C.TypeURLTest,
 			members:    groupMembersOf(ob.Options),
 			detour:     detourOf(ob.Options),
+			selfChecks: ob.Type == C.TypeURLTest && urltestSelfChecks(ob.Options),
 		}
 	}
 	for _, ep := range opts.Endpoints {
@@ -192,6 +284,23 @@ func groupMembersOf(options any) []string {
 	return nil
 }
 
+// urltestSelfChecks reports whether a urltest group still runs its OWN probing
+// schedule. nil/absent SelfCheck means on — the documented compatibility default
+// (option.URLTestOutboundOptions.SelfCheck) — and only an explicit false stands
+// it down. An options struct of an unexpected shape is read as "on", the same
+// direction standDownUnusedSelfCheck refuses to guess in: assuming a checker
+// exists when it does not would leave a target with NO dialler, which is worse
+// than one dialled twice.
+func urltestSelfChecks(options any) bool {
+	switch o := options.(type) {
+	case *option.URLTestOutboundOptions:
+		return o.SelfCheck == nil || *o.SelfCheck
+	case option.URLTestOutboundOptions:
+		return o.SelfCheck == nil || *o.SelfCheck
+	}
+	return true
+}
+
 // detourOf reads DialerOptions.Detour out of any outbound/endpoint/dns-server
 // option struct that carries dialer options (they all embed option.DialerOptions
 // and therefore satisfy DialerOptionsWrapper); "" for everything else.
@@ -215,11 +324,40 @@ func probeablePlanTag(typ, tag string) bool {
 	return !strings.HasPrefix(tag, "egress-")
 }
 
+// planPos is where a measurement sits on a chain: the chain name and the 1-based
+// hop index. The zero value means "not on any chain", which is what every job
+// outside a chain carries.
+//
+// It is threaded through the walk rather than parsed back out of each tag,
+// because only the walk knows the STRUCTURE. A hop wrapper's tag names its own
+// position ("chain-<n>-h<i>"), but a group hop's member copies
+// ("chain-<n>-h<i>-<member>") end in free-form operator text: a node named
+// "h2-eu" would make the tag ambiguous to any parser. Inheriting the position
+// from the wrapper the walk arrived through has no such failure mode.
+type planPos struct {
+	chain string
+	hop   int
+}
+
+// chainPosOf reads a hop WRAPPER tag's own position, or the zero position for
+// anything else.
+func chainPosOf(tag string) planPos {
+	if name, hop, ok := parseChainHopTag(tag); ok {
+		return planPos{chain: name, hop: hop}
+	}
+	return planPos{}
+}
+
 // planTarget accumulates one dial path's job: the tag to dial (the smallest
-// dialable tag, for determinism) and every tag the measurement is recorded under.
+// dialable tag, for determinism), every tag the measurement is recorded under,
+// and where on a chain it sits (planPos).
 type planTarget struct {
 	dial  string
 	store map[string]bool
+	pos   planPos
+	// selfChecked: some group's own checker already dials this path, so the
+	// observatory must not. See ProbeJob.SelfChecked.
+	selfChecked bool
 }
 
 // planWalk is the reachability expansion state.
@@ -234,14 +372,31 @@ type planWalk struct {
 // addTarget registers tag as a measurement under the dial-path key, recording it
 // under itself plus aliases. When several dialable tags share one path (copies of
 // one node through one egress across groups) the smallest dials, deterministically.
-func (w *planWalk) addTarget(key, tag string, aliases ...string) {
+//
+// pos is the chain position and is taken from the FIRST arrival only. Two
+// arrivals at one dial-path key are copies of the same node through the same
+// egress (see the file header), which live outside every chain and therefore
+// carry the zero position anyway; a chain tag's dial key is its own tag, so it is
+// reached once by construction. Never overwriting means a shared key cannot have
+// its position depend on walk order.
+//
+// selfChecked, by contrast, is ANDed across arrivals, and the asymmetry is
+// deliberate: it claims "somebody else already dials this", and one path that
+// reaches the target WITHOUT a checker in front of it (a selector member, a
+// stood-down group) falsifies the claim outright. Merging the pessimistic way
+// can only cost a duplicate probe; merging the optimistic way would leave a
+// target with no dialler at all.
+func (w *planWalk) addTarget(key string, pos planPos, selfChecked bool, tag string, aliases ...string) {
 	t := w.targets[key]
 	if t == nil {
-		t = &planTarget{dial: tag, store: map[string]bool{}}
+		t = &planTarget{dial: tag, store: map[string]bool{}, pos: pos, selfChecked: selfChecked}
 		w.targets[key] = t
-	} else if tag < t.dial {
+	} else {
+		if tag < t.dial {
 			t.dial = tag
 		}
+		t.selfChecked = t.selfChecked && selfChecked
+	}
 	t.store[tag] = true
 	for _, a := range aliases {
 		t.store[a] = true
@@ -251,7 +406,15 @@ func (w *planWalk) addTarget(key, tag string, aliases ...string) {
 // visit expands one root/member reference. Groups recurse into their members;
 // leaves become measurements; a leaf's Detour link is then walked to surface the
 // group hops of a chain (walkDetour).
-func (w *planWalk) visit(tag string) {
+//
+// pos is the chain position INHERITED from the group this reference was expanded
+// out of; a tag that names its own hop position (a chain hop wrapper, typically
+// the exit reached straight from a rule) overrides it.
+//
+// selfChecked says the group this reference came out of probes its own members,
+// so the leaf reached here already has a dialler. A ROOT is reached from a
+// routing rule, which has no checker behind it, so roots start false.
+func (w *planWalk) visit(tag string, pos planPos, selfChecked bool) {
 	if tag == "" || w.visited[tag] {
 		return
 	}
@@ -261,14 +424,17 @@ func (w *planWalk) visit(tag string) {
 		return // dangling reference; box.New would have refused it anyway
 	}
 	w.used[tag] = true
+	if own := chainPosOf(tag); own.chain != "" {
+		pos = own
+	}
 	if ent.group {
 		for _, m := range ent.members {
-			w.visitMember(tag, m)
+			w.visitMember(tag, m, pos, ent.selfChecks)
 		}
 		return
 	}
 	if probeablePlanTag(ent.typ, tag) {
-		w.addTarget(dialKeyTag(tag), tag)
+		w.addTarget(dialKeyTag(tag), pos, selfChecked, tag)
 	}
 	w.walkDetour(ent.detour)
 }
@@ -277,19 +443,30 @@ func (w *planWalk) visit(tag string) {
 // ("group-<group>-m<i>-<member>") is keyed by its (node, egress) dial path — so
 // two groups bound to one egress share the measurement — and recorded under the
 // copy AND the base node tag (the store alias). Every other member is expanded
-// exactly like a root.
-func (w *planWalk) visitMember(group, member string) {
+// exactly like a root, carrying the owning group's chain position down with it:
+// the members of a chain's exit group hop are measurements OF that hop.
+//
+// The EGRESS COPY branch is deliberately never marked self-checked, even when
+// the owning group runs its own checker. Such a job carries a second store tag —
+// the base node tag, the alias that keeps the per-node stats surface filled in
+// without the base outbound (a different dial path) ever being dialled. The
+// group's checker records under the copy tag ALONE (protocol/group/urltest.go
+// stores under RealTag), so handing this measurement over would silently drop
+// the alias and empty /api/stats node_health for every egress-bound node. That
+// is a real duplicate probe knowingly kept, and the alternative is losing data
+// no other writer produces.
+func (w *planWalk) visitMember(group, member string, pos planPos, ownerSelfChecks bool) {
 	ent, ok := w.byTag[member]
 	if !ok {
 		return
 	}
 	if node, isCopy := parseGroupCopyTag(group, member); isCopy && !ent.group {
 		w.used[member] = true
-		w.addTarget(dialKeyCopy(node, ent.detour), member, node)
+		w.addTarget(dialKeyCopy(node, ent.detour), pos, false, member, node)
 		w.walkDetour(ent.detour)
 		return
 	}
-	w.visit(member)
+	w.visit(member, pos, ownerSelfChecks)
 }
 
 // walkDetour follows a probed tag's Detour links toward the router. A group met
@@ -319,9 +496,15 @@ func (w *planWalk) walkDetour(tag string) {
 		return
 	}
 	w.used[tag] = true
+	// A tag met on a detour path names its own position or has none: the walk
+	// arrived here from BELOW (a later hop detouring back), so there is nothing
+	// sensible to inherit.
+	pos := chainPosOf(tag)
 	if !ent.group {
-		if _, isHopWrapper := parseChainExitTag(tag); isHopWrapper && probeablePlanTag(ent.typ, tag) {
-			w.addTarget(dialKeyTag(tag), tag)
+		// A NODE hop wrapper is nobody's member, so no checker exists for it and
+		// the observatory is its only possible dialler.
+		if pos.chain != "" && probeablePlanTag(ent.typ, tag) {
+			w.addTarget(dialKeyTag(tag), pos, false, tag)
 		}
 		w.walkDetour(ent.detour)
 		return
@@ -334,7 +517,11 @@ func (w *planWalk) walkDetour(tag string) {
 		}
 		w.used[m] = true
 		if !ment.group && probeablePlanTag(ment.typ, m) {
-			w.addTarget(dialKeyTag(m), m)
+			// A GROUP hop's members are that wrapper's members: when the wrapper
+			// is a urltest group it probes them itself, and it probes them along
+			// the chain prefix, because each copy carries the previous hop as its
+			// Detour. A selector wrapper has no checker, so those stay ours.
+			w.addTarget(dialKeyTag(m), pos, ent.selfChecks, m)
 		}
 		if next == "" {
 			next = ment.detour // every member detours into the same previous hop
@@ -361,8 +548,14 @@ func dialKeyCopy(node, egress string) string {
 func lenPrefixed(s string) string { return fmt.Sprintf("%d:%s", len(s), s) }
 
 // plansEqual reports whether two plans describe exactly the same measurements —
-// same jobs, same order, same dial tag, same URL, same store set. This is what
-// lets a no-op reconcile keep the observatory's cursor (see ConfigureObservatory).
+// same jobs, same order, same dial tag, same URL, same store set, same chain
+// position. This is what lets a no-op reconcile keep the observatory's cursor
+// (see ConfigureObservatory).
+//
+// The chain position is part of the comparison because it is part of the PLAN,
+// not an annotation on it: it decides the order jobs run in and which of them the
+// ordered walk may skip. A config that moves a node from hop 2 to hop 3 without
+// changing any dial tag is a different plan and must restart the cursor.
 func plansEqual(a, b []ProbeJob) bool {
 	if len(a) != len(b) {
 		return false
@@ -371,6 +564,9 @@ func plansEqual(a, b []ProbeJob) bool {
 		if a[i].Dial != b[i].Dial || a[i].URL != b[i].URL || len(a[i].Store) != len(b[i].Store) {
 			return false
 		}
+		if a[i].Chain != b[i].Chain || a[i].Hop != b[i].Hop || a[i].SelfChecked != b[i].SelfChecked {
+			return false
+		}
 		for j := range a[i].Store {
 			if a[i].Store[j] != b[i].Store[j] {
 				return false

shater/engine/selfcheck.go

@@ -26,6 +26,29 @@ import (
 // EMITTED rules and DNS detours as a whole, and BuildObservatoryPlan is the one
 // place that reachability is computed. Recomputing it in the generator would be
 // a second copy of the same walk, and second copies drift.
+//
+// # NOT the same thing as Engine.ProbeAllowed — do not merge them
+//
+// There are two reasons a group's own schedule stands down, and they are
+// answered in two different places on purpose:
+//
+//	THIS FILE — "no enabled rule reaches this group AT ALL". A property of the
+//	  CONFIG. Decided once per apply, written into the option struct that
+//	  reaches box.New, and unchangeable for the life of that box, because the
+//	  rules cannot change while the box runs.
+//
+//	Engine.ProbeAllowed — "the path in front of this group is dead RIGHT NOW".
+//	  A property of the WORLD. It changes on its own, so it is asked at every
+//	  scheduled check and never stored; that is the only reason a chain hop
+//	  resumes probing by itself when the hop in front of it recovers.
+//
+// A CHAIN HOP WRAPPER is precisely where the difference bites. It is reached by
+// the rules, so it is in the used-set and this function must leave its flag
+// alone — TestStandDownNeverTouchesChainHopWrappers pins that, and it is not a
+// technicality: standing a hop wrapper down here would take a working chain off
+// its own board permanently, with nothing to turn it back on. If a hop wrapper
+// should not probe because the hop in front of it is down, that is the gate's
+// answer, not this one's, and it lasts exactly as long as the failure does.
 
 // standDownUnusedSelfCheck flips SelfCheck to false on every urltest group in
 // opts that the observatory's used-set does not cover, and returns how many it
@@ -48,7 +71,13 @@ import (
 // or something foreign) is skipped rather than guessed at: it did not come from
 // our generator, and silently rebuilding somebody else's option struct is worse
 // than leaving one group's self-check up.
-func standDownUnusedSelfCheck(opts option.Options) int {
+// It also RETURNS the used-set it computed. That set is needed before the new
+// box starts — a group's PostStart asks whether it must keep measuring with no
+// traffic (Engine.ProbeWhenIdle), and the observatory does not publish its own
+// copy until after the swap has succeeded. Handing back the walk that has
+// already run here is cheaper than a second one and, more to the point, cannot
+// disagree with the flags just written from it.
+func standDownUnusedSelfCheck(opts option.Options) (int, map[string]bool) {
 	_, used := BuildObservatoryPlan(opts, "")
 	stood := 0
 	for i := range opts.Outbounds {
@@ -66,5 +95,5 @@ func standDownUnusedSelfCheck(opts option.Options) int {
 		utOpts.SelfCheck = &off
 		stood++
 	}
-	return stood
+	return stood, used
 }

shater/engine/selfcheck_test.go

@@ -29,10 +29,17 @@ func TestStandDownUnusedSelfCheck(t *testing.T) {
 		Route: fixRoute("auto"),
 	}
 
-	stood := standDownUnusedSelfCheck(opts)
+	stood, used := standDownUnusedSelfCheck(opts)
 	if stood != 1 {
 		t.Fatalf("stood down %d group(s), want exactly 1 (idle)", stood)
 	}
+	// The returned used-set is the SAME walk the flags were written from — the
+	// engine publishes it for ProbeWhenIdle before the new box is built, so the
+	// two statements about one group ("keeps its self-check", "keeps it warm")
+	// can never be computed from two different reachability answers.
+	if !used["auto"] || used["idle"] {
+		t.Errorf("used-set = %v, want the reached group in and the unreached one out", used)
+	}
 
 	find := func(tag string) option.Outbound {
 		t.Helper()
@@ -70,7 +77,7 @@ func TestStandDownUnusedSelfCheck(t *testing.T) {
 	// still counted — the function reports plan membership, not novelty) and
 	// changes nothing further. This is what keeps the apply hash stable across
 	// the every-minute reconcile.
-	if again := standDownUnusedSelfCheck(opts); again != 1 {
+	if again, _ := standDownUnusedSelfCheck(opts); again != 1 {
 		t.Fatalf("second pass stood down %d, want 1 (deterministic on identical opts)", again)
 	}
 	if idle.SelfCheck == nil || *idle.SelfCheck {
@@ -144,10 +151,23 @@ func TestStandDownNeverTouchesChainHopWrappers(t *testing.T) {
 		Route: fixRoute("", "chain-p-h4"),
 	}
 
-	stood := standDownUnusedSelfCheck(opts)
+	stood, used := standDownUnusedSelfCheck(opts)
 	if stood != 3 {
 		t.Fatalf("stood down %d group(s), want exactly the 3 base groups sub0/sub1/sub2", stood)
 	}
+	// The hop wrappers are also what ProbeWhenIdle must say yes to: the chain is
+	// reached by a rule, so its hops keep measuring whether or not traffic is
+	// crossing them. The base groups behind them are not, and must not.
+	for _, tag := range []string{"chain-p-h2", "chain-p-h3", "chain-p-h4"} {
+		if !used[tag] {
+			t.Errorf("used-set is missing hop wrapper %q; it would idle out with nothing to replace it", tag)
+		}
+	}
+	for _, tag := range []string{"sub0", "sub1", "sub2"} {
+		if used[tag] {
+			t.Errorf("used-set claims base group %q, which no rule reaches", tag)
+		}
+	}
 
 	utOptions := func(tag string) *option.URLTestOutboundOptions {
 		t.Helper()

shater/generate/byedpi_test.go

@@ -27,7 +27,7 @@ func outboundByTag(opts option.Options, tag string) *option.Outbound {
 
 func byedpiModel(port int) *model.Model {
 	return &model.Model{
-		Globals:  model.DefaultGlobals(),
+		Globals:  nonDNSGlobals(),
 		Egresses: []model.Egress{{Name: "bd", Type: "byedpi", Port: port}},
 		Rules: []model.Rule{
 			{Name: "desync", Enabled: true, Order: 10, Src: []string{"192.168.1.0/24"}, Target: "egress:bd"},

shater/generate/chain_test.go

@@ -47,7 +47,7 @@ func generalRouteOutbound(rt *option.RouteOptions) (string, bool) {
 
 func threeNodeChainModel() *model.Model {
 	return &model.Model{
-		Globals: model.DefaultGlobals(),
+		Globals: nonDNSGlobals(),
 		Nodes: []model.Node{
 			{Name: "a", Enabled: true, URI: "ss://aes-256-gcm:secret@203.0.113.1:8388#a"},
 			{Name: "b", Enabled: true, URI: "ss://aes-256-gcm:secret@203.0.113.2:8388#b"},
@@ -122,7 +122,7 @@ func TestChainMultiHopDetourWiring(t *testing.T) {
 // (no wrapper, no detour outbound).
 func TestChainSingleHopResolvesToHop(t *testing.T) {
 	m := &model.Model{
-		Globals: model.DefaultGlobals(),
+		Globals: nonDNSGlobals(),
 		Nodes: []model.Node{
 			{Name: "a", Enabled: true, URI: "ss://aes-256-gcm:secret@203.0.113.1:8388#a"},
 		},
@@ -210,7 +210,7 @@ func TestChainEmptyHopsWarnsBlocks(t *testing.T) {
 // through the previous hop; the next hop detours into the group wrapper.
 func TestChainGroupHop(t *testing.T) {
 	m := &model.Model{
-		Globals: model.DefaultGlobals(),
+		Globals: nonDNSGlobals(),
 		Nodes: []model.Node{
 			{Name: "a", Enabled: true, URI: "ss://aes-256-gcm:secret@203.0.113.1:8388#a"},
 			{Name: "b", Enabled: true, URI: "ss://aes-256-gcm:secret@203.0.113.2:8388#b"},

shater/generate/devices_test.go

@@ -129,6 +129,13 @@ func TestDevicePerDeviceDNS(t *testing.T) {
 
 // TestDeviceAllowOverridesBlock proves the ordering guarantee: a device's Allow
 // rule is emitted BEFORE its Block rule (allow wins, terminal DNS route action).
+//
+// Since D24 (dns_intercept on by default) the device rules are no longer the
+// FIRST rules in the plane: buildDNS prepends the .lan / private-PTR preservation
+// rule ahead of everything, so that local names keep resolving through dnsmasq
+// even for a device that carries a block list. That is the contract this test now
+// states — rule 0 is the local-zone rule, and allow-before-block holds among the
+// device rules that follow it.
 func TestDeviceAllowOverridesBlock(t *testing.T) {
 	m := baseDeviceModel(model.Device{
 		Name: "kid", Enabled: true, IP: "192.168.1.70",
@@ -139,15 +146,23 @@ func TestDeviceAllowOverridesBlock(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Generate: %v", err)
 	}
-	if opts.DNS == nil || len(opts.DNS.Rules) < 2 {
-		t.Fatalf("expected >=2 device DNS rules (allow+block), got %+v", opts.DNS)
+	if opts.DNS == nil || len(opts.DNS.Rules) == 0 {
+		t.Fatalf("expected a DNS plane, got %+v", opts.DNS)
 	}
-	allow := opts.DNS.Rules[0].DefaultOptions
+	if !isLocalZoneRule(opts.DNS.Rules[0]) {
+		t.Fatalf("rule 0 must be the .lan/PTR preservation rule (it has to outrank per-device policy), got %+v",
+			opts.DNS.Rules[0].DefaultOptions)
+	}
+	rules := nonLocalDNSRules(opts)
+	if len(rules) < 2 {
+		t.Fatalf("expected >=2 device DNS rules (allow+block), got %+v", rules)
+	}
+	allow := rules[0].DefaultOptions
 	if allow.DNSRuleAction.Action != C.RuleActionTypeRoute ||
 		len(allow.DomainSuffix) != 1 || allow.DomainSuffix[0] != "good.example" {
 		t.Fatalf("first device DNS rule must be the allow(good.example)->route, got %+v", allow)
 	}
-	block := opts.DNS.Rules[1].DefaultOptions
+	block := rules[1].DefaultOptions
 	if block.DNSRuleAction.Action != C.RuleActionTypePredefined ||
 		len(block.DomainSuffix) != 1 || block.DomainSuffix[0] != "ads.example" {
 		t.Fatalf("second device DNS rule must be the block(ads.example)->NXDOMAIN, got %+v", block)
@@ -155,21 +170,35 @@ func TestDeviceAllowOverridesBlock(t *testing.T) {
 }
 
 // TestDeviceNoneEmitsNothing proves the guard: no devices (or none enabled) adds
-// no device route rules and no device DNS rules — identical to a pre-Phase-6 build.
+// no device route rules and no DEVICE DNS rules.
+//
+// "No DNS rules at all" is no longer the right statement of that guard, and
+// weakening it to "some rules" would test nothing. Since D24 every intercepting
+// plane carries exactly one rule that is not ours to suppress — the .lan / PTR
+// preservation rule — so the guard is now: the device codegen contributes NOTHING,
+// and what remains is that single local-zone rule, unchanged by a device list that
+// is empty or entirely disabled.
 func TestDeviceNoneEmitsNothing(t *testing.T) {
+	assertOnlyLocalZoneRule := func(t *testing.T, what string, opts option.Options) {
+		t.Helper()
+		if opts.Route == nil || len(opts.Route.Rules) != 2 {
+			t.Fatalf("%s must emit only sniff+hijackdns route rules, got %+v", what, opts.Route)
+		}
+		if devRules := nonLocalDNSRules(opts); len(devRules) != 0 {
+			t.Fatalf("%s must emit no device DNS rules, got %+v", what, devRules)
+		}
+		if opts.DNS == nil || len(opts.DNS.Rules) != 1 || !isLocalZoneRule(opts.DNS.Rules[0]) {
+			t.Fatalf("%s must keep exactly the .lan/PTR preservation rule, got %+v", what, opts.DNS)
+		}
+	}
+
 	// No devices at all.
 	m := baseDeviceModel()
 	opts, _, err := GenerateWithWarnings(m)
 	if err != nil {
 		t.Fatalf("Generate: %v", err)
 	}
-	// Only sniff + hijack-dns route rules remain (no device/general rules).
-	if opts.Route == nil || len(opts.Route.Rules) != 2 {
-		t.Fatalf("no-devices model must emit only sniff+hijackdns route rules, got %+v", opts.Route)
-	}
-	if opts.DNS != nil && len(opts.DNS.Rules) != 0 {
-		t.Fatalf("no-devices model must emit no DNS rules, got %+v", opts.DNS.Rules)
-	}
+	assertOnlyLocalZoneRule(t, "no-devices model", opts)
 
 	// A single DISABLED device: same result.
 	m2 := baseDeviceModel(model.Device{Name: "off", Enabled: false, IP: "192.168.1.80", Block: []string{"x.example"}})
@@ -177,10 +206,5 @@ func TestDeviceNoneEmitsNothing(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Generate: %v", err)
 	}
-	if len(opts2.Route.Rules) != 2 {
-		t.Fatalf("disabled-only model must emit only sniff+hijackdns route rules, got %+v", opts2.Route.Rules)
-	}
-	if opts2.DNS != nil && len(opts2.DNS.Rules) != 0 {
-		t.Fatalf("disabled-only model must emit no DNS rules, got %+v", opts2.DNS.Rules)
-	}
+	assertOnlyLocalZoneRule(t, "disabled-only model", opts2)
 }

shater/generate/dns.go

@@ -18,8 +18,9 @@ import (
 // buildDNS assembles the typed option.DNSOptions from the model resolvers +
 // dns_rules (v1.14 removed the flat servers list and top-level fakeip). Each
 // server carries its own Detour (anti-leak: DNS through the proxy/direct as
-// configured); a server whose detour cannot be resolved falls back to the
-// default outbound with a warning.
+// configured); a server whose detour cannot be resolved is FAIL-CLOSED to `block`
+// with a warning, so it stops answering rather than falling out to the plain WAN
+// (see dnsDetour).
 //
 // Returns nil when the model declares no resolvers (engine uses its built-ins).
 func (b *builder) buildDNS() *option.DNSOptions {
@@ -34,7 +35,7 @@ func (b *builder) buildDNS() *option.DNSOptions {
 			b.warnf("per-device DNS block/allow configured but no resolvers; inert (needs a resolver for the in-engine DNS plane)")
 		}
 		if b.m.Globals.DNSIntercept {
-			b.warnf("dns_intercept enabled but no resolvers configured; .lan/local DNS won't be preserved (engine falls back to built-in DNS)")
+			b.warnf("dns_intercept is ON but there is no `config resolver`: every intercepted query is answered by the router's own system resolver (the engine's built-in `local` transport reads /etc/resolv.conf, which on OpenWrt is dnsmasq -> your provider, in the clear). .lan and the private PTR zones keep working, but DNS filtering, per-device DNS rules and the DNS anti-leak detour are inert until you add a resolver.")
 		}
 		if b.m.Globals.BlockDoH {
 			b.warnf("block_doh enabled but no resolvers configured; the DoH NXDOMAIN rules (incl. the Firefox use-application-dns.net canary) are NOT emitted — only the :443 route rejects apply")
@@ -60,7 +61,7 @@ func (b *builder) buildDNS() *option.DNSOptions {
 			b.warnf("per-device DNS block/allow configured but no valid resolvers built; inert")
 		}
 		if b.m.Globals.DNSIntercept {
-			b.warnf("dns_intercept enabled but no valid resolvers built; .lan/local DNS won't be preserved (engine falls back to built-in DNS)")
+			b.warnf("dns_intercept is ON but no `config resolver` could be built (check the warnings above): every intercepted query is answered by the router's own system resolver (the engine's built-in `local` transport reads /etc/resolv.conf, which on OpenWrt is dnsmasq -> your provider, in the clear). .lan and the private PTR zones keep working, but DNS filtering, per-device DNS rules and the DNS anti-leak detour are inert until a resolver builds.")
 		}
 		if b.m.Globals.BlockDoH {
 			b.warnf("block_doh enabled but no valid resolvers built; the DoH NXDOMAIN rules (incl. the Firefox use-application-dns.net canary) are NOT emitted — only the :443 route rejects apply")
@@ -116,6 +117,14 @@ func (b *builder) buildDNS() *option.DNSOptions {
 		servers = append(servers, *b.endpointResolverServer)
 	}
 
+	// IMPLICIT default_domain_resolver. The DNS plane is complete at this point, so
+	// this is the first place that can count its transports — which is the only thing
+	// the engine's dialer branches on (see implicitBootstrapResolver). Skipped when the
+	// operator named an endpoint_resolver: that one already set the field and MUST win.
+	if b.endpointResolver() == "" && len(servers) >= 2 {
+		b.bootstrapResolverTag = b.implicitBootstrapResolver(final, localDNSTag, serverTags, &servers)
+	}
+
 	// DoH-block NXDOMAIN rules sit FIRST (BlockDoH): they answer known public DoH
 	// hostnames + the Firefox canary with NXDOMAIN so clients fall back to plaintext
 	// :53. Empty when BlockDoH is off. The synthetic local-dns rule prepended at the
@@ -137,16 +146,29 @@ func (b *builder) buildDNS() *option.DNSOptions {
 	// slice in arbitrary order, and the panel promises "lower Order runs earlier /
 	// first match wins". Mirrors sortedRuleIndices (generate.go) for route rules:
 	// stable sort by (Order, original index).
+	//
+	// A rule naming a resolver that does not exist is NOT dropped — see
+	// dnsRuleUnresolvedAction for why a dropped rule is a leak and what replaces it.
 	for _, i := range sortedDNSRuleIndices(b.m.DNSRules) {
 		dr := b.m.DNSRules[i]
-		if !serverTags[dr.Resolver] {
-			b.warnf("dns_rule -> resolver %q: unknown resolver, skipped", dr.Resolver)
-			continue
+		known := serverTags[dr.Resolver]
+		if !known {
+			b.warnf("dns_rule -> resolver %q: no such resolver — wrong name, or it was removed, or it was skipped for "+
+				"a bad address/type. This rule is FAIL-CLOSED: the names (and clients) it singles out now get NXDOMAIN "+
+				"instead of quietly falling through to the default resolver %q. Falling through is what this used to do, "+
+				"and it sent exactly the lookups you had singled out to a resolver you did not choose for them — over "+
+				"whatever path that one uses. Restore the resolver, or point the rule at one that exists.",
+				dr.Resolver, final)
 		}
 		b.warnUnrecognisedPrefixes(fmt.Sprintf("dns_rule %q", dr.Resolver), dr.MatchDomain)
-		if rule, ok := b.dnsRule(dr); ok {
-			rules = append(rules, rule)
+		rule, ok := b.dnsRule(dr)
+		if !ok {
+			continue
 		}
+		if !known {
+			rule.DefaultOptions.DNSRuleAction = dnsRuleUnresolvedAction()
+		}
+		rules = append(rules, rule)
 	}
 
 	// Globals.ResolverFallback — the real failover chain, APPENDED last so it only
@@ -272,19 +294,11 @@ func (b *builder) endpointResolver() string {
 
 	// Clone under a dedicated tag with Detour forced direct (bootstrap-direct; see the
 	// doc comment). Guard the tag against colliding with any real resolver server tag.
-	clone := *res
-	clone.Detour = "direct"
-	tag := endpointResolverTagPrefix + res.Name
 	taken := make(map[string]bool, len(b.m.Resolvers))
 	for i := range b.m.Resolvers {
 		taken[b.m.Resolvers[i].Name] = true
 	}
-	for taken[tag] {
-		tag += "-x"
-	}
-	clone.Name = tag
-
-	srv, ok := b.dnsServer(clone)
+	srv, tag, ok := b.bootstrapDirectServer(*res, endpointResolverTagPrefix, taken)
 	if !ok {
 		// dnsServer already warned (bad address/type); leave the resolver unset.
 		b.warnf("endpoint_resolver %q (%s): could not be built as a bootstrap-direct server; route.default_domain_resolver is left unset", name, src)
@@ -295,6 +309,167 @@ func (b *builder) endpointResolver() string {
 	return tag
 }
 
+// bootstrapDirectServer clones res into a DNS server whose detour is FORCED to
+// "direct", under a tag built from prefix+res.Name and guarded against every name in
+// taken. ok=false when the resolver cannot be built as a server at all (bad address,
+// unknown type) — the caller then decides what to say and never emits a reference.
+//
+// Every warning dnsServer raises while building the clone is DISCARDED, deliberately.
+// The clone differs from what the operator wrote in exactly one field — Detour, forced
+// to a target that always resolves — so each diagnostic it can produce (an ignored
+// pool, a missing address, a type that does not exist) was already produced verbatim
+// for the client-facing copy of the same resolver. Emitting them twice would make one
+// typo look like two faults, and would attribute one of them to a server tag the
+// operator never wrote and cannot find in their config.
+func (b *builder) bootstrapDirectServer(res model.Resolver, prefix string, taken map[string]bool) (option.DNSServerOptions, string, bool) {
+	clone := res
+	clone.Detour = tagDirect
+	tag := prefix + res.Name
+	for taken[tag] {
+		tag += "-x"
+	}
+	clone.Name = tag
+
+	mark := len(b.warnings)
+	srv, ok := b.dnsServer(clone)
+	b.warnings = b.warnings[:mark]
+	if !ok {
+		return option.DNSServerOptions{}, "", false
+	}
+	return srv, tag, true
+}
+
+// bootstrapResolverTagPrefix names the synthetic DNS server the IMPLICIT
+// default_domain_resolver is cloned into. Deliberately distinct from
+// endpointResolverTagPrefix: one of those tags is a server the operator asked for by
+// name, the other is one the generator chose for them, and a log line or a panel row
+// naming either has to be able to say which.
+const bootstrapResolverTagPrefix = "shater-bootstrap-dns-"
+
+// implicitBootstrapResolver emits the DNS server that route.default_domain_resolver
+// points at when the operator named NO endpoint_resolver, and returns its tag. It
+// returns "" when nothing usable could be built, in which case the field stays unset —
+// a dangling default_domain_resolver aborts box.New, so it is never emitted on spec.
+//
+// # Why the field has to be set at all
+//
+// The engine's dialer resolves a domain SERVER ADDRESS — a proxy node written as a
+// hostname, and any domain destination handed to the `direct` outbound — through
+// whatever DNS it is told to use. common/dialer/dialer.go picks that at construction
+// time, and switches behaviour on the NUMBER OF DNS TRANSPORTS:
+//
+//	1 transport,   no default_domain_resolver -> dnsTransport.Default(), i.e. the
+//	                                             `final` server, DNS rules bypassed
+//	2+ transports, no default_domain_resolver -> the transport stays nil and
+//	                                             dns/router.go drops into
+//	                                             lookupWithRules — the full CLIENT
+//	                                             DNS rule chain
+//
+// The second is not a milder version of the first, it is a different plane. Sending a
+// node's own hostname down the client rule chain means a blocklist, a block_doh
+// NXDOMAIN rule or any dns_rule can now answer it: one sloppy entry in an ad list, or
+// a fake-IP default resolver, stops being an ad that got through and becomes a tunnel
+// that never comes up. It is also what raises the engine's `missing-domain-resolver`
+// deprecation.
+//
+// None of that is specific to dns_intercept — two `config resolver`s were always
+// enough to reach it. dns_intercept only made it UNIVERSAL, because the synthetic
+// `shater-local-dns` server it adds is a second transport by itself. So the trigger
+// here is the condition the engine actually branches on (two or more transports), not
+// the toggle that happened to expose it.
+//
+// # Why THIS server
+//
+// A clone of the effective default resolver with its detour forced to "direct" —
+// exactly the shape endpointResolver builds for the explicit case, for the reason
+// spelled out there: a proxy server's own domain CANNOT be resolved through the proxy
+// that domain is needed to open. That is a bootstrap loop, and its symptom (tunnel
+// never comes up, nothing resolves, no log line names either as the cause) is the
+// worst outcome on offer here.
+//
+// `final` rather than something fabricated, because it is the upstream the operator
+// already trusts with every query no rule claimed — and cloning preserves its TYPE, so
+// a DoH default stays DoH: the bootstrap lookups remain encrypted and still go to the
+// chosen provider. The single thing dropped is the tunnel hop, which is the one hop
+// that cannot exist yet.
+//
+// Fall-back order, because a fake-IP server invents addresses and would hand the dialer
+// a synthetic IP no tunnel can ever connect to:
+//
+//	final -> first non-fakeip resolver that built -> the synthetic local server
+//	(dnsmasq, already direct) -> "" (field left unset)
+func (b *builder) implicitBootstrapResolver(final, localDNSTag string, serverTags map[string]bool, servers *[]option.DNSServerOptions) string {
+	res, substituted := b.bootstrapSource(final, serverTags)
+	if res == nil {
+		// Every resolver that built is fake-IP. dnsmasq (the synthetic local server) is
+		// the only real, already-direct transport left; with dns_intercept off there is
+		// not even that, and the field stays unset. warnFakeIPDefault has already said
+		// what a fake-IP default costs for CLIENT queries — this says what it costs the
+		// router's own bootstrap, which is a different (and invisible) bill.
+		if localDNSTag != "" {
+			b.warnf("every configured resolver is fake-IP, and a fake-IP server invents addresses instead of asking anyone, so it cannot resolve a real proxy server's domain. Proxy server domains are therefore resolved by the router's own system resolver (dnsmasq -> your provider, in the clear) — add a normal resolver, or name one with globals.endpoint_resolver.")
+		}
+		return localDNSTag
+	}
+	srv, tag, ok := b.bootstrapDirectServer(*res, bootstrapResolverTagPrefix, serverTags)
+	if !ok {
+		return localDNSTag
+	}
+	*servers = append(*servers, srv)
+	if substituted {
+		b.warnf("resolver_default %q is a fake-IP resolver, which invents addresses and cannot resolve a real proxy server's domain, so proxy server domains are resolved through %q instead (forced direct). Name the one you want with globals.endpoint_resolver if that is not it.", final, res.Name)
+	}
+	b.warnBootstrapInTheClear(*res)
+	return tag
+}
+
+// bootstrapSource picks the resolver to clone for the implicit bootstrap server:
+// `final` when it is usable, otherwise the first non-fakeip resolver that actually
+// built. substituted reports that the pick is NOT the default resolver, so the caller
+// can say so rather than quietly resolving node domains somewhere else.
+func (b *builder) bootstrapSource(final string, serverTags map[string]bool) (res *model.Resolver, substituted bool) {
+	if !b.resolverIsFakeIP(final) {
+		for i := range b.m.Resolvers {
+			if b.m.Resolvers[i].Name == final {
+				return &b.m.Resolvers[i], false
+			}
+		}
+	}
+	for i := range b.m.Resolvers {
+		r := &b.m.Resolvers[i]
+		if serverTags[r.Name] && !b.resolverIsFakeIP(r.Name) {
+			return r, true
+		}
+	}
+	return nil, false
+}
+
+// warnBootstrapInTheClear names the one cost the implicit bootstrap server has that
+// the operator did not choose and cannot see.
+//
+// It fires only for a PLAINTEXT resolver (plain/udp/tcp) that the operator had
+// deliberately routed through a proxy. For that config, and only that one, forcing the
+// bootstrap copy direct means the hostnames of the operator's OWN nodes go to their
+// provider in clear text from their real address — while every other lookup on the box
+// is still tunnelled, which is exactly the sort of gap that looks like it isn't there.
+//
+// Silent for doh/dot (the clone is still encrypted to the same upstream, so nothing
+// leaks but the fact that a DoH connection exists) and silent for a resolver that was
+// never detoured through a tunnel in the first place: nothing changed for it.
+func (b *builder) warnBootstrapInTheClear(res model.Resolver) {
+	switch strings.ToLower(strings.TrimSpace(res.Type)) {
+	case "plain", "udp", "", "tcp":
+	default:
+		return
+	}
+	detour := strings.TrimSpace(res.Detour)
+	if detour == "" || strings.EqualFold(detour, tagDirect) || strings.EqualFold(detour, tagBlock) {
+		return
+	}
+	b.warnf("resolver %q: its queries are routed through %q, but the ADDRESS of the proxy %q opens has to be resolved before that proxy exists — so those lookups are made directly, over the plain WAN. %q is a plaintext resolver, so your provider sees the hostnames of your own nodes, coming from your real address, while everything else stays tunnelled. Use a doh/dot resolver, or point globals.endpoint_resolver at one you are content to expose.",
+		res.Name, detour, detour, res.Name)
+}
+
 // resolverFallbackRules implements Globals.ResolverFallback: when the primary
 // resolver produces NO response, the query is retried against the fallback.
 //
@@ -394,6 +569,35 @@ func (b *builder) resolverFallbackRules(final string, serverTags map[string]bool
 	}
 }
 
+// dnsRuleUnresolvedAction is what a dns_rule does when the resolver it names does
+// not exist. It is the DNS-plane twin of ruleKillFallback (route.go), and it
+// exists for the identical reason.
+//
+// A dns_rule used to be DROPPED whole in that case, which reads as harmless and is
+// not: the domains it named then fell through to whatever the default resolver is.
+// The operator singled those names out to be resolved somewhere specific — through
+// the tunnel, by the corporate resolver, by the one server that answers them
+// correctly — and dropping the rule silently converted that policy into the
+// default policy. route.go says it best about routing rules: it is "a silent leak
+// of exactly the traffic the operator singled out", and a DNS lookup leaks the
+// name itself, which is the part a provider actually collects.
+//
+// So the rule stays, with its matchers intact, and answers NXDOMAIN. That is
+// visible (the name stops resolving, the warning says why), scoped (only the
+// rule's own matchers are affected, everything else resolves normally) and safe
+// (nothing is sent anywhere the operator did not ask for).
+//
+// A predefined NXDOMAIN rather than action=reject on two counts: it is the answer
+// this codebase already uses to refuse a name (dnsfilter.go), and a reject action
+// built in Go with an unset Method PANICS the engine at match time
+// (route/rule/rule_action.go RuleActionReject.Error) — the normalisation that
+// would fill it in only runs on the JSON unmarshal path.
+//
+// The rule is still skipped entirely when it has NO usable matcher (dnsRule
+// returns ok=false): an unmatched-but-emitted rule would NXDOMAIN every query in
+// the network, which is a far larger blast radius than the fault deserves.
+func dnsRuleUnresolvedAction() option.DNSRuleAction { return predefinedNXDOMAIN() }
+
 // resolverIsFakeIP reports whether the named model resolver is a fakeip server.
 func (b *builder) resolverIsFakeIP(name string) bool {
 	for _, r := range b.m.Resolvers {
@@ -452,8 +656,8 @@ func (b *builder) resolverIsFakeIP(name string) bool {
 // hosts, dhcp, mdns, tailscale, legacy. Those are missing capabilities, not
 // defects; adding one is a model+panel change, not a generator change.
 func (b *builder) dnsServer(r model.Resolver) (option.DNSServerOptions, bool) {
-	detour := b.dnsDetour(r)
 	kind := strings.ToLower(strings.TrimSpace(r.Type))
+	detour := b.dnsDetour(r, kind)
 	b.warnIgnoredResolverFields(r, kind)
 
 	// A remote transport with no address aborts box.New ("invalid server address")
@@ -643,16 +847,65 @@ func (b *builder) warnFakeIPDefault(final string) {
 		"Make a normal resolver the default and point a dns_rule at %q for just the domains you want fake-IP to handle.", final, final)
 }
 
-// dnsDetour resolves the resolver's Detour target to an outbound tag; an empty
-// or unresolved detour means "use the default outbound" (returns "").
-func (b *builder) dnsDetour(r model.Resolver) string {
-	if strings.TrimSpace(r.Detour) == "" {
+// dnsDetour resolves the resolver's Detour target to the outbound tag its queries
+// must be dialed through.
+//
+//	""        — no detour is configured. The server dials over the default route,
+//	            which is what "no detour" has always meant and is not a fault.
+//	<tag>     — the detour resolved; queries go through that outbound.
+//	tagBlock  — the detour is DANGLING; this resolver's queries are BLOCKED.
+//
+// # Why a dangling detour blocks (FAIL-CLOSED)
+//
+// This used to return "" for an unresolvable detour and say it was "using default
+// outbound". It was not: "" is not a default outbound, it is
+// dialer.NewWithOptions' NewDefault branch — an ordinary system socket on the
+// router's own WAN. So a resolver written as `detour node:vps` — written that way
+// precisely so the ISP never sees which names this network looks up — silently
+// became a plaintext UDP :53 query to 1.1.1.1 over the provider's link, from the
+// router's real address, the moment the node it named went away. Switching a node
+// off from the panel is enough to trigger it, and it happens WHILE the kill-switch
+// is closed and the traffic itself is blocked: the connections stop, the list of
+// domains keeps flowing to the ISP, and nothing in the UI says so.
+//
+// It was also the last place in this generator where a dangling reference degraded
+// into a direct path. Every neighbour already fails closed and says why —
+// egressDetourOrBlock ("there is deliberately no fail-open opt-out here"),
+// ruleKillFallback, chain.go's L1 hop — and wgdedup's retargetDroppedTags rewrites
+// THIS VERY FIELD (opts.DNS.Servers[i]'s detour) to `block` when it drops an
+// endpoint. One field with two opposite policies, the outcome depending on which
+// piece of code noticed the breakage first, is not a policy at all.
+//
+// # What the operator gets instead
+//
+// `block` is a real outbound (always emitted, outbound.go) whose dial returns
+// EPERM, so the DNS transport fails on every exchange. Concretely: queries routed
+// to this resolver get a transport error instead of an answer; if it is also
+// globals.resolver_default, that is EVERY query no earlier rule claimed, i.e. name
+// resolution stops network-wide until the detour is fixed. That is the correct
+// fail-closed outcome — a router that resolves nothing is recoverable, a router
+// that quietly hands the ISP its whole DNS history is not — and it is exactly why
+// the warning below names the consequence instead of the mechanism. When
+// globals.resolver_fallback is configured it still applies: the failover chain
+// fires on "no response", which a blocked transport produces.
+//
+// fakeip is excluded because its detour is genuinely inert (a fake-IP server mints
+// answers locally and dials nothing at all); blocking it would be a lie in the
+// other direction, and warnIgnoredResolverFields already reports the ignored field.
+func (b *builder) dnsDetour(r model.Resolver, kind string) string {
+	if kind == "fakeip" || strings.TrimSpace(r.Detour) == "" {
 		return ""
 	}
 	tag, ok := b.resolveTarget(r.Detour)
 	if !ok {
-		b.warnf("resolver %q: unresolved detour %q, using default outbound", r.Name, r.Detour)
-		return ""
+		b.warnf("resolver %q: its detour %q does not exist — wrong name, or the node/group/chain/egress it named was "+
+			"removed or could not be built. The detour is FAIL-CLOSED, so this resolver now answers NOTHING: its "+
+			"queries are blocked instead of being sent out over the plain WAN in clear text, which is the exact leak "+
+			"the detour exists to prevent (your provider would get the full list of names your network looks up, from "+
+			"your real address, while the kill switch blocks the traffic itself). If this is the default resolver, "+
+			"name resolution stops for the whole network until you restore %q or point the resolver somewhere else.",
+			r.Name, r.Detour, strings.TrimSpace(r.Detour))
+		return tagBlock
 	}
 	return tag
 }

shater/generate/dns_faildetour_test.go

@@ -0,0 +1,195 @@
+package generate
+
+// The DNS plane's two dangling-reference paths, both of which used to degrade into
+// "resolve it anyway, somewhere else".
+//
+// A DNS leak is not a smaller version of a traffic leak. The traffic can be
+// blocked by the kill switch and still leave the provider holding the complete
+// list of names this network looks up, which is the part that identifies the
+// household. So a broken DNS reference has to fail CLOSED for exactly the same
+// reason a broken egress binding does.
+
+import (
+	"strings"
+	"testing"
+
+	C "github.com/sagernet/sing-box/constant"
+
+	"github.com/sagernet/sing-box/shater/model"
+)
+
+// warnContaining returns the first warning containing all of the fragments.
+func warnContaining(warns []string, fragments ...string) (string, bool) {
+	for _, w := range warns {
+		all := true
+		for _, f := range fragments {
+			if !strings.Contains(w, f) {
+				all = false
+				break
+			}
+		}
+		if all {
+			return w, true
+		}
+	}
+	return "", false
+}
+
+// DEFECT 1. A resolver whose detour cannot be resolved used to get Detour="" and a
+// warning saying it was "using default outbound". "" is not a default outbound: it
+// is an ordinary system socket on the router's own WAN. So switching off the node
+// a resolver detoured through turned every lookup in the network into a plaintext
+// :53 query to 1.1.1.1 across the provider's link, from the real address, while
+// the kill switch was closed and the traffic itself was being blocked.
+//
+// The detour must fail closed to `block`, like every other dangling reference in
+// this generator (egressDetourOrBlock, ruleKillFallback, chain L1, and
+// wgdedup.retargetDroppedTags — which rewrites this same field to `block`).
+func TestResolverDanglingDetourFailsClosed(t *testing.T) {
+	m := &model.Model{
+		Globals: model.Globals{ResolverDefault: "cf"},
+		Resolvers: []model.Resolver{
+			// node:vps existed until the operator switched the node off.
+			{Name: "cf", Type: "udp", Address: "1.1.1.1", Detour: "node:vps"},
+		},
+	}
+	opts, warns, err := GenerateWithWarnings(m)
+	if err != nil {
+		t.Fatalf("GenerateWithWarnings: %v", err)
+	}
+	srv, ok := dnsServerByTag(opts.DNS, "cf")
+	if !ok {
+		t.Fatalf("resolver %q must still be emitted; servers=%+v", "cf", opts.DNS)
+	}
+	if got := udpServerDetour(t, srv); got != tagBlock {
+		t.Fatalf("LEAK: resolver with a dangling detour has detour %q, want %q — "+
+			"an empty detour sends every query out over the plain WAN in clear text, "+
+			"handing the provider the full list of names this network resolves.", got, tagBlock)
+	}
+	// The warning has to name the CONSEQUENCE, not the mechanism: "fail-closed" is
+	// also what makes apply/warnings.go grade it critical.
+	w, ok := warnContaining(warns, `resolver "cf"`, "FAIL-CLOSED")
+	if !ok {
+		t.Fatalf("expected a fail-closed warning naming the resolver; warnings=%v", warns)
+	}
+	for _, want := range []string{"answers NOTHING", "plain WAN", "name resolution stops"} {
+		if !strings.Contains(w, want) {
+			t.Errorf("warning must state the consequence, missing %q:\n%s", want, w)
+		}
+	}
+}
+
+// A detour that RESOLVES must be untouched — the fix may only change the broken
+// case.
+func TestResolverLiveDetourUnchanged(t *testing.T) {
+	m := &model.Model{
+		Globals:   model.Globals{ResolverDefault: "cf"},
+		Resolvers: []model.Resolver{{Name: "cf", Type: "udp", Address: "1.1.1.1", Detour: "direct"}},
+	}
+	opts, _, err := GenerateWithWarnings(m)
+	if err != nil {
+		t.Fatalf("GenerateWithWarnings: %v", err)
+	}
+	srv, ok := dnsServerByTag(opts.DNS, "cf")
+	if !ok {
+		t.Fatalf("resolver must be emitted; dns=%+v", opts.DNS)
+	}
+	if got := udpServerDetour(t, srv); got != tagDirect {
+		t.Fatalf("a live detour must survive: detour = %q, want %q", got, tagDirect)
+	}
+}
+
+// A fakeip resolver dials nothing at all, so its detour is genuinely inert. Failing
+// it closed would be a lie in the other direction — and would contradict
+// warnIgnoredResolverFields, which reports the same field as ignored.
+func TestFakeIPResolverDanglingDetourIsNotFailedClosed(t *testing.T) {
+	m := &model.Model{
+		Globals: model.Globals{ResolverDefault: "real"},
+		Resolvers: []model.Resolver{
+			{Name: "real", Type: "udp", Address: "1.1.1.1"},
+			{Name: "fake", Type: "fakeip", Detour: "node:gone"},
+		},
+	}
+	_, warns, err := GenerateWithWarnings(m)
+	if err != nil {
+		t.Fatalf("GenerateWithWarnings: %v", err)
+	}
+	if _, bad := warnContaining(warns, `resolver "fake"`, "FAIL-CLOSED"); bad {
+		t.Errorf("a fakeip resolver's detour is inert; it must not be reported as fail-closed:\n%v", warns)
+	}
+	if _, ok := warnContaining(warns, `resolver "fake"`, "IGNORED"); !ok {
+		t.Errorf("a fakeip resolver's detour must still be reported as ignored:\n%v", warns)
+	}
+}
+
+// DEFECT 1, adjacent (dns.go's dns_rule loop). A rule naming a resolver that no
+// longer exists used to be DROPPED, which sounds harmless and is not: the names it
+// singled out then fell through to the default resolver — the silent leak of
+// exactly the lookups the operator had singled out, which route.go already refuses
+// for routing rules. The rule now stays and answers NXDOMAIN.
+func TestDNSRuleUnknownResolverFailsClosed(t *testing.T) {
+	m := &model.Model{
+		Globals:   model.Globals{ResolverDefault: "cf"},
+		Resolvers: []model.Resolver{{Name: "cf", Type: "udp", Address: "1.1.1.1"}},
+		DNSRules: []model.DNSRule{
+			{Resolver: "work-dns", MatchDomain: []string{"intranet.example"}},
+		},
+	}
+	opts, warns, err := GenerateWithWarnings(m)
+	if err != nil {
+		t.Fatalf("GenerateWithWarnings: %v", err)
+	}
+	if opts.DNS == nil {
+		t.Fatal("expected a DNS plane")
+	}
+	var found bool
+	for _, r := range opts.DNS.Rules {
+		d := r.DefaultOptions
+		if len(d.Domain) != 1 || d.Domain[0] != "intranet.example" {
+			continue
+		}
+		found = true
+		if d.DNSRuleAction.Action != C.RuleActionTypePredefined {
+			t.Fatalf("a dns_rule whose resolver is gone must answer with a predefined action, got %+v",
+				d.DNSRuleAction)
+		}
+		if d.DNSRuleAction.PredefinedOptions.Rcode == nil {
+			t.Fatalf("expected an NXDOMAIN rcode, got %+v", d.DNSRuleAction.PredefinedOptions)
+		}
+		if d.DNSRuleAction.RouteOptions.Server != "" {
+			t.Fatalf("the rule must not route to any server, got %q", d.DNSRuleAction.RouteOptions.Server)
+		}
+	}
+	if !found {
+		t.Fatalf("LEAK: the dns_rule was dropped, so %q now resolves through the default resolver — "+
+			"exactly the lookup the operator singled out, sent somewhere they did not choose. rules=%+v",
+			"intranet.example", opts.DNS.Rules)
+	}
+	if _, ok := warnContaining(warns, `resolver "work-dns"`, "FAIL-CLOSED", "NXDOMAIN"); !ok {
+		t.Fatalf("expected a fail-closed warning for the dangling dns_rule; warnings=%v", warns)
+	}
+}
+
+// The guard that must survive: a dns_rule with NO usable matcher is still skipped
+// entirely. Emitting it with an NXDOMAIN action would answer EVERY query in the
+// network with "no such name".
+func TestDNSRuleUnknownResolverWithNoMatcherIsSkipped(t *testing.T) {
+	m := &model.Model{
+		Globals:   model.Globals{ResolverDefault: "cf"},
+		Resolvers: []model.Resolver{{Name: "cf", Type: "udp", Address: "1.1.1.1"}},
+		DNSRules:  []model.DNSRule{{Resolver: "gone"}},
+	}
+	opts, _, err := GenerateWithWarnings(m)
+	if err != nil {
+		t.Fatalf("GenerateWithWarnings: %v", err)
+	}
+	for _, r := range opts.DNS.Rules {
+		d := r.DefaultOptions
+		if d.DNSRuleAction.Action != C.RuleActionTypePredefined {
+			continue
+		}
+		if len(d.Domain)+len(d.DomainSuffix)+len(d.DomainKeyword)+len(d.SourceIPCIDR)+len(d.RuleSet) == 0 {
+			t.Fatalf("a matcher-less NXDOMAIN rule would blackhole the whole network: %+v", d)
+		}
+	}
+}

shater/generate/dnsfilter_test.go

@@ -80,19 +80,26 @@ func TestDNSFilterInlineBlockAllowValidates(t *testing.T) {
 		t.Fatalf("expected rule-sets bl-ads, bl-zeros and al-safe, got %+v", opts.Route.RuleSet)
 	}
 
-	// DNS rules: allow FIRST (route->cf), then nxdomain block, then zero block.
-	if opts.DNS == nil || len(opts.DNS.Rules) < 3 {
-		t.Fatalf("expected >=3 DNS rules (allow+nxdomain+zero), got %+v", opts.DNS)
+	// DNS rules: the .lan/PTR preservation rule dns_intercept prepends comes first
+	// (D24 — local names outrank the filter), then allow (route->cf), then the
+	// nxdomain block, then the zero block. The FILTER's own ordering is what this
+	// test is about, so it is asserted over the rules that are the filter's.
+	if opts.DNS == nil || len(opts.DNS.Rules) == 0 || !isLocalZoneRule(opts.DNS.Rules[0]) {
+		t.Fatalf("rule 0 must be the .lan/PTR preservation rule, got %+v", opts.DNS)
+	}
+	filterRules := nonLocalDNSRules(opts)
+	if len(filterRules) < 3 {
+		t.Fatalf("expected >=3 filter DNS rules (allow+nxdomain+zero), got %+v", filterRules)
 	}
 
-	allow := opts.DNS.Rules[0].DefaultOptions
+	allow := filterRules[0].DefaultOptions
 	if allow.RuleSet[0] != "al-safe" || allow.DNSRuleAction.Action != C.RuleActionTypeRoute ||
 		allow.DNSRuleAction.RouteOptions.Server != "cf" {
 		t.Fatalf("first DNS rule must be allow(al-safe)->route:cf, got %+v", allow)
 	}
 
 	// nxdomain block: predefined action, Rcode NXDOMAIN, no answer records.
-	nx := opts.DNS.Rules[1].DefaultOptions
+	nx := filterRules[1].DefaultOptions
 	if nx.RuleSet[0] != "bl-ads" || nx.DNSRuleAction.Action != C.RuleActionTypePredefined {
 		t.Fatalf("second DNS rule must be block(bl-ads)->predefined, got %+v", nx)
 	}
@@ -105,7 +112,7 @@ func TestDNSFilterInlineBlockAllowValidates(t *testing.T) {
 	}
 
 	// zero block: predefined action, A 0.0.0.0 + AAAA :: (IPv6 on), no Rcode.
-	zero := opts.DNS.Rules[2].DefaultOptions
+	zero := filterRules[2].DefaultOptions
 	if zero.RuleSet[0] != "bl-zeros" || zero.DNSRuleAction.Action != C.RuleActionTypePredefined {
 		t.Fatalf("third DNS rule must be block(bl-zeros)->predefined, got %+v", zero)
 	}
@@ -149,10 +156,13 @@ func TestDNSFilterZeroNoIPv6(t *testing.T) {
 	if !changed {
 		t.Fatalf("expected changed==true (warnings: %v)", warns)
 	}
-	if opts.DNS == nil || len(opts.DNS.Rules) < 1 {
+	// Index past the .lan/PTR preservation rule dns_intercept prepends (D24): the
+	// subject here is the zero-block ANSWER, not where it sits in the plane.
+	filterRules := nonLocalDNSRules(opts)
+	if len(filterRules) < 1 {
 		t.Fatalf("expected a block DNS rule, got %+v", opts.DNS)
 	}
-	ans := opts.DNS.Rules[0].DefaultOptions.DNSRuleAction.PredefinedOptions.Answer
+	ans := filterRules[0].DefaultOptions.DNSRuleAction.PredefinedOptions.Answer
 	if len(ans) != 1 {
 		t.Fatalf("zero block (IPv6 off) must carry ONLY the A record, got %+v", ans)
 	}
@@ -338,8 +348,12 @@ func TestDNSFilterOffEmitsNothing(t *testing.T) {
 	if len(opts.Route.RuleSet) != 0 {
 		t.Fatalf("filter off must emit no rule-sets, got %+v", opts.Route.RuleSet)
 	}
-	if opts.DNS != nil && len(opts.DNS.Rules) != 0 {
-		t.Fatalf("filter off must emit no DNS rules, got %+v", opts.DNS.Rules)
+	// "No DNS rules at all" stopped being the right statement of this guard when
+	// dns_intercept became the default (D24): an intercepting plane always carries
+	// the .lan/PTR preservation rule, which is not the filter's. The guard is that
+	// the FILTER contributes nothing.
+	if fr := nonLocalDNSRules(opts); len(fr) != 0 {
+		t.Fatalf("filter off must emit no filter DNS rules, got %+v", fr)
 	}
 }
 

shater/generate/dpi_test.go

@@ -35,7 +35,7 @@ func routeActionFor(opts option.Options, tag string) *option.RouteActionOptions
 
 func dpiModel(dpi string) *model.Model {
 	return &model.Model{
-		Globals:  model.DefaultGlobals(),
+		Globals:  nonDNSGlobals(),
 		Egresses: []model.Egress{{Name: "frag", Type: "direct", DPI: dpi}},
 		Rules: []model.Rule{
 			{Name: "desync", Enabled: true, Order: 10, Src: []string{"192.168.1.0/24"}, Target: "egress:frag"},

shater/generate/egress_test.go

@@ -13,7 +13,7 @@ import (
 // the egress tag (multi-WAN). No copies: the binding lands on the node itself.
 func TestNodeEgressBindsOutbound(t *testing.T) {
 	m := &model.Model{
-		Globals:  model.DefaultGlobals(),
+		Globals:  nonDNSGlobals(),
 		Egresses: []model.Egress{{Name: "wan2", Type: "direct"}},
 		Nodes: []model.Node{
 			{Name: "a", Enabled: true, URI: "ss://aes-256-gcm:secret@203.0.113.1:8388#a", Egress: "wan2"},
@@ -80,7 +80,7 @@ func TestNodeEgressMissingIsFailClosed(t *testing.T) {
 // outbound (instead of dialing directly from the router).
 func TestChainEgressEntryHop(t *testing.T) {
 	m := &model.Model{
-		Globals:  model.DefaultGlobals(),
+		Globals:  nonDNSGlobals(),
 		Egresses: []model.Egress{{Name: "wan2", Type: "direct"}},
 		Nodes: []model.Node{
 			{Name: "x", Enabled: true, URI: "ss://aes-256-gcm:secret@203.0.113.1:8388#x"},

shater/generate/endpoint_resolver_test.go

@@ -4,6 +4,7 @@ import (
 	"strings"
 	"testing"
 
+	C "github.com/sagernet/sing-box/constant"
 	"github.com/sagernet/sing-box/option"
 
 	"github.com/sagernet/sing-box/shater/model"
@@ -210,11 +211,16 @@ func TestEndpointResolverIsAlwaysDirect(t *testing.T) {
 	}
 }
 
-// TestEndpointResolverAbsentUnset: with no endpoint_resolver configured the field
-// stays unset (prior behaviour preserved, engine uses its built-in resolver).
+// TestEndpointResolverAbsentUnset: one transport and no endpoint_resolver leaves the
+// field unset. That is not merely "the feature is off": with a single DNS transport
+// the engine's dialer already resolves a domain server address through
+// dnsTransport.Default() (common/dialer/dialer.go), so there is nothing to fix and
+// nothing to say. dns_intercept is explicitly OFF here — it would add the synthetic
+// local server and make this a TWO-transport plane, which is the other case entirely
+// (TestBootstrapResolverSetWhenPlaneHasTwoTransports).
 func TestEndpointResolverAbsentUnset(t *testing.T) {
 	m := &model.Model{
-		Globals: model.Globals{ResolverDefault: "cf"},
+		Globals: model.Globals{ResolverDefault: "cf"}, // zero value => DNSIntercept off
 		Resolvers: []model.Resolver{
 			{Name: "cf", Type: "udp", Address: "1.1.1.1", Detour: "direct"},
 		},
@@ -227,3 +233,160 @@ func TestEndpointResolverAbsentUnset(t *testing.T) {
 		t.Fatalf("default_domain_resolver must be unset when the feature is off, got %+v", opts.Route.DefaultDomainResolver)
 	}
 }
+
+// bootstrapServerTag mirrors dns.go's bootstrapResolverTagPrefix + resolver name.
+func bootstrapServerTag(resolver string) string {
+	return bootstrapResolverTagPrefix + resolver
+}
+
+// TestBootstrapResolverNotThroughTheTunnel is the regression this file exists for
+// since dns_intercept became the default.
+//
+// The config is the one we RECOMMEND against leaks: a single resolver, deliberately
+// detoured through the proxy node. The node itself is written as a DOMAIN, so its
+// address has to be resolved before the tunnel it provides can exist.
+//
+// With dns_intercept on, the DNS plane carries two transports (the resolver plus the
+// synthetic `shater-local-dns`), and at two transports common/dialer/dialer.go stops
+// using dnsTransport.Default() and leaves the transport nil — dns/router.go then
+// resolves the node's own hostname through lookupWithRules, i.e. the CLIENT DNS plane,
+// whose default server is the very resolver that dials through this node. A bootstrap
+// loop, in the one configuration written specifically to be safe.
+//
+// So: default_domain_resolver must be set, and the server it names must be DIRECT.
+func TestBootstrapResolverNotThroughTheTunnel(t *testing.T) {
+	g := model.DefaultGlobals() // dns_intercept ON (D24) => two DNS transports
+	g.ResolverDefault = "cf"
+	m := &model.Model{
+		Globals: g,
+		Nodes: []model.Node{
+			// A DOMAIN server address — the whole point: it must be resolved to dial.
+			{Name: "vps", Enabled: true, URI: "ss://aes-256-gcm:secret@vps.example.com:8388#vps"},
+		},
+		Resolvers: []model.Resolver{
+			{Name: "cf", Type: "udp", Address: "1.1.1.1", Detour: "node:vps"},
+		},
+	}
+	opts, warns, err := GenerateWithWarnings(m)
+	if err != nil {
+		t.Fatalf("GenerateWithWarnings: %v", err)
+	}
+	if opts.Route == nil || opts.Route.DefaultDomainResolver == nil {
+		t.Fatalf("default_domain_resolver must be set: without it the node's own hostname is "+
+			"resolved through the client DNS plane, whose default server dials through that node; warns=%v", warns)
+	}
+	want := bootstrapServerTag("cf")
+	if got := opts.Route.DefaultDomainResolver.Server; got != want {
+		t.Fatalf("default_domain_resolver.server = %q, want the bootstrap clone %q", got, want)
+	}
+	srv, ok := dnsServerByTag(opts.DNS, want)
+	if !ok {
+		t.Fatalf("bootstrap server %q must exist among the DNS servers (a dangling reference aborts box.New); servers=%+v", want, opts.DNS.Servers)
+	}
+	if d := udpServerDetour(t, srv); d != "direct" {
+		t.Fatalf("the server that resolves node addresses MUST NOT go through the tunnel those nodes open: detour = %q, want %q", d, "direct")
+	}
+	// The client-facing resolver keeps its anti-leak detour: the bootstrap copy is an
+	// addition, not a downgrade of the client DNS plane.
+	client, ok := dnsServerByTag(opts.DNS, "cf")
+	if !ok {
+		t.Fatalf("client resolver %q must still be emitted", "cf")
+	}
+	if d := udpServerDetour(t, client); d != "vps" {
+		t.Fatalf("client resolver detour = %q, want the proxy node %q", d, "vps")
+	}
+	// A plaintext resolver forced direct for bootstrap hands the node's hostname to the
+	// provider in the clear. That is the one cost the operator did not choose, so it is
+	// never silent.
+	if !warnsHaveSub(warns, "hostnames of your own nodes") {
+		t.Fatalf("a plaintext bootstrap lookup must be warned about, got %v", warns)
+	}
+}
+
+// TestBootstrapResolverDoesNotOverrideExplicit: an operator-configured
+// endpoint_resolver keeps ownership of route.default_domain_resolver. The implicit
+// bootstrap server must not be built at all — a second synthetic server would be a
+// third transport nobody asked for and a tag nobody can find in their config.
+func TestBootstrapResolverDoesNotOverrideExplicit(t *testing.T) {
+	g := model.DefaultGlobals() // dns_intercept ON => the implicit path is live
+	g.ResolverDefault = "cf"
+	g.EndpointResolver = "q9"
+	m := &model.Model{
+		Globals: g,
+		Resolvers: []model.Resolver{
+			{Name: "cf", Type: "udp", Address: "1.1.1.1", Detour: "direct"},
+			{Name: "q9", Type: "udp", Address: "9.9.9.9", Detour: "direct"},
+		},
+	}
+	opts, _, err := GenerateWithWarnings(m)
+	if err != nil {
+		t.Fatalf("GenerateWithWarnings: %v", err)
+	}
+	if opts.Route == nil || opts.Route.DefaultDomainResolver == nil {
+		t.Fatalf("default_domain_resolver must be set; route=%+v", opts.Route)
+	}
+	want := endpointServerTag("q9")
+	if got := opts.Route.DefaultDomainResolver.Server; got != want {
+		t.Fatalf("the explicit endpoint_resolver must win: default_domain_resolver.server = %q, want %q", got, want)
+	}
+	for _, tag := range []string{bootstrapServerTag("cf"), bootstrapServerTag("q9")} {
+		if _, ok := dnsServerByTag(opts.DNS, tag); ok {
+			t.Fatalf("no implicit bootstrap server may be emitted when endpoint_resolver is set, found %q", tag)
+		}
+	}
+}
+
+// TestBootstrapResolverSetWhenPlaneHasTwoTransports pins the TRIGGER: two or more DNS
+// transports, which is the condition common/dialer/dialer.go actually branches on —
+// not the dns_intercept toggle that happened to expose it. Two plain resolvers with
+// intercept OFF reach it just as well, and did so long before D24.
+//
+// It also pins the shipped default's shape: a single DoH resolver plus intercept is a
+// two-transport plane, so the field is set, the clone stays DoH (encrypted to the same
+// upstream — only the tunnel hop is dropped) and nothing is warned about.
+func TestBootstrapResolverSetWhenPlaneHasTwoTransports(t *testing.T) {
+	m := &model.Model{
+		Globals: model.Globals{ResolverDefault: "cf"}, // intercept OFF
+		Resolvers: []model.Resolver{
+			{Name: "cf", Type: "udp", Address: "1.1.1.1", Detour: "direct"},
+			{Name: "q9", Type: "udp", Address: "9.9.9.9", Detour: "direct"},
+		},
+	}
+	opts, warns, err := GenerateWithWarnings(m)
+	if err != nil {
+		t.Fatalf("GenerateWithWarnings: %v", err)
+	}
+	if opts.Route == nil || opts.Route.DefaultDomainResolver == nil {
+		t.Fatalf("two transports without dns_intercept must still set default_domain_resolver; warns=%v", warns)
+	}
+	if got, want := opts.Route.DefaultDomainResolver.Server, bootstrapServerTag("cf"); got != want {
+		t.Fatalf("default_domain_resolver.server = %q, want a direct clone of the default resolver %q", got, want)
+	}
+
+	// The shipped default: one DoH resolver + intercept. The clone must still be DoH.
+	g := model.DefaultGlobals()
+	g.ResolverDefault = "cf"
+	m2 := &model.Model{
+		Globals: g,
+		Resolvers: []model.Resolver{
+			{Name: "cf", Type: "doh", Address: "https://1.1.1.1/dns-query", Detour: "direct"},
+		},
+	}
+	opts2, warns2, err := GenerateWithWarnings(m2)
+	if err != nil {
+		t.Fatalf("GenerateWithWarnings: %v", err)
+	}
+	if opts2.Route == nil || opts2.Route.DefaultDomainResolver == nil {
+		t.Fatalf("dns_intercept adds a second transport, so the field must be set; warns=%v", warns2)
+	}
+	srv, ok := dnsServerByTag(opts2.DNS, bootstrapServerTag("cf"))
+	if !ok {
+		t.Fatalf("bootstrap clone missing; servers=%+v", opts2.DNS.Servers)
+	}
+	if srv.Type != C.DNSTypeHTTPS {
+		t.Fatalf("the clone must keep the resolver's TYPE (DoH stays DoH), got %q", srv.Type)
+	}
+	if len(warns2) != 0 {
+		t.Fatalf("the shipped default shape must generate no warnings, got %v", warns2)
+	}
+}

shater/generate/enum_verdict_test.go

@@ -43,7 +43,7 @@ func warnMatching(warns []string, subs ...string) []string {
 // carrying the given strategy.
 func twoNodeGroupModel(strategy string) *model.Model {
 	return &model.Model{
-		Globals: model.DefaultGlobals(),
+		Globals: nonDNSGlobals(),
 		Nodes: []model.Node{
 			{Name: "n1", Enabled: true, URI: ss("203.0.113.1")},
 			{Name: "n2", Enabled: true, URI: ss("203.0.113.2")},
@@ -313,7 +313,7 @@ func TestFailoverWarnsOnceAcrossChainCopy(t *testing.T) {
 
 func egressModel(egType string) *model.Model {
 	return &model.Model{
-		Globals:  model.DefaultGlobals(),
+		Globals:  nonDNSGlobals(),
 		Egresses: []model.Egress{{Name: "e1", Type: egType, Interface: "eth1"}},
 	}
 }
@@ -375,7 +375,7 @@ func TestEgressTypeUnknownWarns(t *testing.T) {
 // egress, but the native tls_* flags are never applied to one.
 func TestByedpiEgressDPIWarnsIgnored(t *testing.T) {
 	m := &model.Model{
-		Globals:  model.DefaultGlobals(),
+		Globals:  nonDNSGlobals(),
 		Egresses: []model.Egress{{Name: "bd", Type: "byedpi", Port: 1080, DPI: "fragment"}},
 	}
 	_, warns, err := GenerateWithWarnings(m)
@@ -387,7 +387,7 @@ func TestByedpiEgressDPIWarnsIgnored(t *testing.T) {
 	}
 	for _, d := range []string{"", "off"} {
 		m2 := &model.Model{
-			Globals:  model.DefaultGlobals(),
+			Globals:  nonDNSGlobals(),
 			Egresses: []model.Egress{{Name: "bd", Type: "byedpi", DPI: d}},
 		}
 		if _, w, _ := GenerateWithWarnings(m2); len(w) != 0 {
@@ -413,7 +413,7 @@ func TestEgressPortIgnoredOnNonByedpi(t *testing.T) {
 	}
 	// byedpi uses it, so no warning.
 	m := &model.Model{
-		Globals:  model.DefaultGlobals(),
+		Globals:  nonDNSGlobals(),
 		Egresses: []model.Egress{{Name: "e1", Type: "byedpi", Port: 9050}},
 	}
 	if _, warns, _ := GenerateWithWarnings(m); len(warns) != 0 {
@@ -564,7 +564,7 @@ func findChainOutbound(b *builder, tag string) *option.Outbound {
 // resolves must still produce a plain detour to the egress, with no warning.
 func TestEgressBindingValidIsUnaffected(t *testing.T) {
 	m := &model.Model{
-		Globals:  model.DefaultGlobals(),
+		Globals:  nonDNSGlobals(),
 		Egresses: []model.Egress{{Name: "wan2", Type: "direct"}},
 		Nodes: []model.Node{
 			{Name: "n1", Enabled: true, URI: ss("203.0.113.1"), Egress: "wan2"},

shater/generate/fixture_globals_test.go

@@ -0,0 +1,79 @@
+package generate
+
+import (
+	"strings"
+
+	C "github.com/sagernet/sing-box/constant"
+	"github.com/sagernet/sing-box/option"
+
+	"github.com/sagernet/sing-box/shater/model"
+)
+
+// nonDNSGlobals is model.DefaultGlobals for a fixture whose subject is NOT the
+// DNS plane: egress binding, chain flattening, rule-set compilation, byedpi
+// wiring.
+//
+// D24 made `dns_intercept` ON by default, so a model built straight from
+// DefaultGlobals now declares "force every LAN :53 into the engine, including the
+// queries addressed to the router". buildDNS answers that declaration honestly on
+// both sides: a model that intercepts DNS while configuring no `config resolver`
+// earns a warning (there is no resolver plane to intercept INTO — the queries end
+// up at the system resolver), and a model that does have one gets the .lan / PTR
+// preservation rule prepended ahead of everything else.
+//
+// Both are correct, and both are noise in a test about SOCKS outbounds. So the
+// fixtures that use this helper state plainly that they do not intercept DNS,
+// rather than keeping an "unexpected warnings" assertion that would silently
+// become a DNS assertion. The tests that ARE about the DNS plane —
+// dns_intercept_test.go, dnsfilter_test.go, doh_test.go, devices_test.go — keep
+// the real default: that is where the intercept contract belongs and is pinned.
+func nonDNSGlobals() model.Globals {
+	g := model.DefaultGlobals()
+	g.DNSIntercept = false
+	return g
+}
+
+// isLocalZoneRule reports whether a DNS rule is the .lan / private-PTR
+// preservation rule that dns_intercept prepends (buildDNS): a domain_suffix rule
+// routing those zones to the synthetic `shater-local-dns` server, which points at
+// dnsmasq on 127.0.0.1:53.
+//
+// Since D24 that rule is at index 0 of EVERY generated DNS plane that has a
+// resolver, which is why the assertions below stopped being able to say
+// "opts.DNS.Rules[0] is my rule". Matching on the server tag (a PREFIX — buildDNS
+// appends "-x" if the operator already used that name) keeps those tests about
+// their own subject instead of about an offset.
+func isLocalZoneRule(r option.DNSRule) bool {
+	a := r.DefaultOptions.DNSRuleAction
+	return a.Action == C.RuleActionTypeRoute && strings.HasPrefix(a.RouteOptions.Server, "shater-local-dns")
+}
+
+// nonLocalDNSRules is opts.DNS.Rules without the local-zone preservation rule —
+// in order, so index-based "allow first, then block" assertions keep working and
+// keep meaning what they say.
+func nonLocalDNSRules(opts option.Options) []option.DNSRule {
+	if opts.DNS == nil {
+		return nil
+	}
+	var out []option.DNSRule
+	for _, r := range opts.DNS.Rules {
+		if isLocalZoneRule(r) {
+			continue
+		}
+		out = append(out, r)
+	}
+	return out
+}
+
+// hasDNSServer reports whether the emitted DNS plane carries a server with tag.
+func hasDNSServer(opts option.Options, tag string) bool {
+	if opts.DNS == nil {
+		return false
+	}
+	for _, s := range opts.DNS.Servers {
+		if s.Tag == tag {
+			return true
+		}
+	}
+	return false
+}

shater/generate/generate.go

@@ -199,6 +199,14 @@ type builder struct {
 	endpointResolverServer   *option.DNSServerOptions
 	endpointResolverComputed bool
 
+	// bootstrapResolverTag is the IMPLICIT default_domain_resolver: the tag buildDNS
+	// emits when the operator configured no endpoint_resolver but the DNS plane ends
+	// up carrying two or more transports (see implicitBootstrapResolver). "" when the
+	// explicit endpoint resolver is in play, when a single transport makes the field
+	// unnecessary, or when nothing usable could be built. Consumed once, after
+	// buildRoute AND buildDNS have both run, by GenerateWithWarningsAt.
+	bootstrapResolverTag string
+
 	warnings []string
 }
 
@@ -276,6 +284,18 @@ func GenerateWithWarningsAt(m *model.Model, now time.Time) (option.Options, []st
 	route := b.buildRoute()
 	dns := b.buildDNS()
 
+	// route.default_domain_resolver, second half. buildRoute already set it from an
+	// operator-configured endpoint_resolver (route.go), which always wins. What it
+	// could NOT decide is the implicit case: that depends on how many DNS transports
+	// the plane ends up with, and only buildDNS knows, because it runs second and
+	// because dns_intercept's synthetic local server is counted too. So the implicit
+	// tag is wired here, where both halves have run, and only into a field the
+	// explicit path left empty. See implicitBootstrapResolver for why the field must
+	// be set at all and why it points where it does.
+	if route != nil && route.DefaultDomainResolver == nil && b.bootstrapResolverTag != "" {
+		route.DefaultDomainResolver = &option.DomainResolveOptions{Server: b.bootstrapResolverTag}
+	}
+
 	// Fold in the multi-hop chain outbounds/endpoints materialised by resolveChain
 	// during buildRoute/buildDNS (a `chain:<name>` target reached from a rule,
 	// device or dns detour). Done AFTER every resolveTarget call so all referenced

shater/generate/generate_test.go

@@ -93,8 +93,11 @@ func TestShadowsocksTproxyKillSwitchClosed(t *testing.T) {
 	if !hasRouteToOutbound(opts, "ss1") {
 		t.Fatalf("expected a route rule with action route->ss1")
 	}
-	// DoH resolver present and default.
-	if opts.DNS == nil || len(opts.DNS.Servers) != 1 || opts.DNS.Final != "cf-doh" {
+	// DoH resolver present and default. The server COUNT is no longer 1: since D24
+	// dns_intercept is on by default, so buildDNS also emits the synthetic
+	// `shater-local-dns` that keeps .lan resolving through dnsmasq. What this test
+	// is about is that the operator's DoH server is there and is the catch-all.
+	if opts.DNS == nil || opts.DNS.Final != "cf-doh" || !hasDNSServer(opts, "cf-doh") {
 		t.Fatalf("expected doh resolver 'cf-doh' as DNS final, got %+v", opts.DNS)
 	}
 }
@@ -219,7 +222,12 @@ func TestAllReachableProtocols(t *testing.T) {
 	const vmessLink = "vmess://eyJ2IjoiMiIsInBzIjoidm1lc3MtdyIsImFkZCI6ImV4YW1wbGUubmV0IiwicG9ydCI6IjQ0MyIsImlkIjoiMzMzMzMzMzMtMzMzMy0zMzMzLTMzMzMtMzMzMzMzMzMzMzMzIiwiYWlkIjoiMCIsInNjeSI6ImF1dG8iLCJuZXQiOiJ3cyIsImhvc3QiOiJleGFtcGxlLm5ldCIsInBhdGgiOiIvd3MiLCJ0bHMiOiJ0bHMifQ=="
 
 	m := &model.Model{
-		Globals:  model.DefaultGlobals(),
+		// nonDNSGlobals, not DefaultGlobals: the subject here is "every share-link
+		// protocol reaches box.New", and this model configures no `config resolver`,
+		// so the D24 default (dns_intercept ON) would earn its own honest warning
+		// about an intercept with nothing to intercept into — turning the
+		// no-warnings assertion below into a DNS assertion by accident.
+		Globals:  nonDNSGlobals(),
 		Inbounds: []model.Inbound{{Name: "lan", Enabled: true, Type: "tproxy", TproxyPort: 12363}},
 		Nodes: []model.Node{
 			{Name: "vless-ws", Enabled: true, URI: "vless://11111111-1111-1111-1111-111111111111@example.com:443?type=ws&security=tls&path=/vl&host=cdn.example.com&sni=cdn.example.com#vless-ws"},

shater/generate/group_egress_test.go

@@ -56,7 +56,7 @@ func anyDetour(t *testing.T, opts option.Options, tag string) string {
 // and one deliberately not.
 func twoGroupsOneSubModel() *model.Model {
 	return &model.Model{
-		Globals:  model.DefaultGlobals(),
+		Globals:  nonDNSGlobals(),
 		Egresses: []model.Egress{{Name: "awg", Type: "direct"}},
 		Nodes: []model.Node{
 			{Name: "n1", Enabled: true, URI: ss("203.0.113.1"), FromSub: "qomar"},

shater/generate/route_matchers_test.go

@@ -737,7 +737,7 @@ func TestChainCyclesTerminateFailClosed(t *testing.T) {
 // chainFlattenModel is a model with three usable nodes and a closed kill-switch,
 // ready for the chain-flatten cases below to attach chains + one targeting rule.
 func chainFlattenModel() *model.Model {
-	g := model.DefaultGlobals()
+	g := nonDNSGlobals()
 	g.KillSwitch = "closed"
 	return &model.Model{
 		Globals: g,

shater/generate/ruleset_test.go

@@ -85,7 +85,7 @@ func contains(list []string, want string) bool {
 // so it runs on every platform.
 func TestRoutingRuleSetInlineDomain(t *testing.T) {
 	m := &model.Model{
-		Globals: model.DefaultGlobals(),
+		Globals: nonDNSGlobals(),
 		Rulesets: []model.Ruleset{
 			{Name: "ads", Type: "domain", Source: "inline", Entries: []string{"ads.example", "doubleclick.net"}},
 		},
@@ -134,7 +134,7 @@ func TestRoutingRuleSetInlineDomain(t *testing.T) {
 // looks configured and matches nothing.
 func TestRoutingRuleSetInlineDomainRegex(t *testing.T) {
 	m := &model.Model{
-		Globals: model.DefaultGlobals(),
+		Globals: nonDNSGlobals(),
 		Rulesets: []model.Ruleset{
 			{Name: "ads", Type: "domain", Source: "inline", Entries: []string{`regexp:^ads\.`}},
 		},
@@ -173,7 +173,7 @@ func TestRoutingRuleSetInlineDomainRegex(t *testing.T) {
 // and the route rule references it.
 func TestRoutingRuleSetInlineIPCIDR(t *testing.T) {
 	m := &model.Model{
-		Globals: model.DefaultGlobals(),
+		Globals: nonDNSGlobals(),
 		Rulesets: []model.Ruleset{
 			{Name: "cn", Type: "ipcidr", Source: "inline", Entries: []string{"10.0.0.0/8", "192.168.0.0/16"}},
 		},
@@ -259,7 +259,7 @@ func TestRoutingRuleSetUnusedNotEmitted(t *testing.T) {
 // The single-category tag now carries the category suffix (rs-<name>-<category>).
 func TestRoutingRuleSetGeositeCategory(t *testing.T) {
 	m := &model.Model{
-		Globals: model.DefaultGlobals(),
+		Globals: nonDNSGlobals(),
 		Rulesets: []model.Ruleset{
 			{Name: "yt", Source: "geosite", Categories: []string{"youtube"}},
 		},
@@ -302,7 +302,7 @@ func TestRoutingRuleSetGeositeCategory(t *testing.T) {
 // references the ruleset matches BOTH tags.
 func TestRoutingRuleSetGeositeMultiCategory(t *testing.T) {
 	m := &model.Model{
-		Globals: model.DefaultGlobals(),
+		Globals: nonDNSGlobals(),
 		Rulesets: []model.Ruleset{
 			{Name: "social", Source: "geosite", Categories: []string{"youtube", "telegram"}},
 		},
@@ -346,7 +346,7 @@ func TestRoutingRuleSetGeositeMultiCategory(t *testing.T) {
 // lower-cased (rs-ru-ru).
 func TestRoutingRuleSetGeoipCountryLowercased(t *testing.T) {
 	m := &model.Model{
-		Globals: model.DefaultGlobals(),
+		Globals: nonDNSGlobals(),
 		Rulesets: []model.Ruleset{
 			{Name: "ru", Source: "geoip", Categories: []string{"RU"}},
 		},
@@ -1185,7 +1185,7 @@ func TestFileSourceExistingPathEmitted(t *testing.T) {
 		t.Fatalf("write: %v", err)
 	}
 	m := &model.Model{
-		Globals: model.DefaultGlobals(),
+		Globals: nonDNSGlobals(),
 		Rulesets: []model.Ruleset{
 			{Name: "j", Source: "file", Path: jsonPath},
 			{Name: "s", Source: "file", Path: srsPath},

shater/generate/shipped_tags_linux_test.go

@@ -165,7 +165,11 @@ func TestShippedTagSetConstructsDeclaredProtocols(t *testing.T) {
 	// No inbound on purpose: this test is about protocol construction, and a
 	// tproxy listener would demand CAP_NET_ADMIN from every runner. The tproxy
 	// path is covered by the rest of the suite.
-	m := &model.Model{Globals: model.DefaultGlobals(), Nodes: nodes}
+	// nonDNSGlobals, not DefaultGlobals: this test is about PROTOCOL construction
+	// under the shipped tag set, and it asserts zero generator warnings. With the
+	// default dns_intercept (D24) a model with no `config resolver` earns a DNS
+	// warning that has nothing to say about whether vless or hysteria2 compiled in.
+	m := &model.Model{Globals: nonDNSGlobals(), Nodes: nodes}
 
 	opts, warns, changed := applyAndClose(t, m)
 	if !changed {

shater/logsink/logsink.go

@@ -57,6 +57,7 @@ import (
 	"os"
 	"path/filepath"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	"github.com/sagernet/sing-box/shater/model"
@@ -123,6 +124,29 @@ const (
 	// an evicted entry that had swallowed copies prints its summary on the way
 	// out (marked "repeat table full"), so a counter is never simply dropped.
 	maxRepeatKeys = 256
+
+	// outQueueCap bounds the hand-off between the goroutines that LOG and the one
+	// goroutine that WRITES. See the Sink type comment for why the hand-off exists
+	// at all. The queue is the entire budget for "the destination has stopped
+	// accepting bytes": past it, lines are dropped and counted, never waited on.
+	//
+	// Why 4096: one line is ~150 B, so a full queue is well under a megabyte on a
+	// 512 MB router, and at the observed flood rate (~7 lines/s) it is ten minutes
+	// of backlog — far longer than any transient stall worth buffering, and short
+	// enough that a permanently wedged reader costs a bounded amount of memory
+	// instead of the daemon.
+	outQueueCap = 4096
+
+	// outControlTimeout bounds how long a CONTROL op (a Reconfigure, a Sync) waits
+	// for the writer. Control ops may not be dropped — a dropped Reconfigure would
+	// leave the writer on the old destination for good — so they block, but never
+	// indefinitely: a wedged writer must cost the caller a bounded delay, which is
+	// the whole point of this file's change.
+	outControlTimeout = 2 * time.Second
+
+	// closeDrainTimeout bounds Close's wait for the queue to drain. Shutdown must
+	// complete even when the log destination is the thing that is stuck.
+	closeDrainTimeout = 3 * time.Second
 )
 
 // FilePath returns the log-file location for the given persistence choice.
@@ -185,22 +209,52 @@ func ConfigFromGlobals(g model.Globals) Config {
 
 // Sink is the shared line sink. Create with New; write producers' raw log bytes
 // via Write (io.Writer); flip settings with Reconfigure; Close on shutdown.
+//
+// # Two halves, and why
+//
+// The sink is split down the middle: a FRONT that every logging goroutine runs
+// (line assembly and repeat suppression, under mu) and a BACK that exactly one
+// goroutine runs — the actual writes to stderr and to the file. They are joined
+// by a bounded queue, and the front NEVER blocks on it: a full queue drops the
+// line and counts it.
+//
+// That split is not tidiness, it is the difference between a degraded log and an
+// unreachable router. Under procd the daemon's stderr is a PIPE, read by
+// logd/logread. A pipe holds 64 KiB; once it is full and the reader has stopped
+// draining it — logd restarting, a `logread -f` that went away, a stopped
+// consumer — a write to it blocks forever. The sink used to perform that write
+// while holding mu, and mu is taken by Write, i.e. by every line the process
+// logs. One stuck pipe therefore froze the engine, every panel handler, the apply
+// path and the signal loop at once: a daemon alive to `kill -0` and answering
+// nothing, which is precisely the unresponsiveness cmd/shaterd/ctlclient.go's
+// timeouts were written around.
+//
+// With the split, the only thing a wedged destination can stop is the single
+// drain goroutine. Everything else keeps running and loses log lines — the
+// correct thing to sacrifice, and the same principle Write already stated: a
+// logging destination that fails must degrade, never propagate its failure back
+// into the code that was merely trying to log.
+//
+// ORDER is preserved end to end. Lines and control operations travel in one
+// stream, so a Reconfigure takes effect exactly at its place in it and the lines
+// written before it still reach the destination they were written for. Sync and
+// Close are the barriers that turn "queued" back into "written".
 type Sink struct {
+	// outDropped counts lines discarded because the output queue was full. First
+	// field, and an atomic type, so it needs no lock and stays 64-bit aligned on
+	// the 32-bit router targets.
+	outDropped atomic.Uint64
+
 	mu  sync.Mutex
 	cfg Config
 
-	// stderr is the syslog half's destination — the REAL os.Stderr in the
-	// daemon (procd relays it to logread). Injected so tests can observe it.
-	stderr io.Writer
-
 	buf []byte // un-terminated tail awaiting its '\n'
 
-	file     *os.File // active segment; nil until first file write (lazy open)
-	fileSize int64    // bytes in the active segment
-	fileErr  bool     // a standing open/write failure was already warned about
-
-	suspended bool      // persistent-path disk guard tripped
-	lastProbe time.Time // last disk-free probe
+	// outCh carries lines and control ops to the drain goroutine. Close nils it
+	// under mu, which is what makes the subsequent close(ch) safe: no sender can
+	// still be holding it.
+	outCh     chan outOp
+	drainDone chan struct{} // closed when the drain goroutine has finished
 
 	// repeat suppression (emitLocked and the repeatSeries helpers below).
 	// series is the table of messages seen inside their window, keyed by
@@ -211,12 +265,46 @@ type Sink struct {
 	repeatTimer *time.Timer // armed at the earliest series deadline, if any
 	closed      bool        // Close ran: the timer must not write any more
 
-	// test seams
+	// --- the back half: owned by the drain goroutine, and touched by nothing
+	// else once New has returned ---
+
+	// stderr is the syslog half's destination — the REAL os.Stderr in the
+	// daemon (procd relays it to logread). Injected so tests can observe it.
+	stderr io.Writer
+
+	outCfg      Config // the configuration the WRITER is currently applying
+	outReported uint64 // outDropped as of the last drop notice printed
+
+	file     *os.File // active segment; nil until first file write (lazy open)
+	fileSize int64    // bytes in the active segment
+	fileErr  bool     // a standing open/write failure was already warned about
+
+	suspended bool      // persistent-path disk guard tripped
+	lastProbe time.Time // last disk-free probe
+
+	closeErr error // the file-close result; published by closing drainDone
+
+	// test seams. Written only before the first Write (by New, or by a test on a
+	// fresh sink); read by both halves from then on.
 	now    func() time.Time
 	free   func(string) (uint64, bool)
 	window time.Duration // repeatWindow, overridable in tests
 }
 
+// outOp is one item on the queue between the halves. Exactly one role is
+// populated per op, and they share one stream so their ORDER is the order they
+// were produced in:
+//
+//	line != nil   a complete line to fan out, with the timestamp it was written at
+//	cfg  != nil   install this destination configuration (from Reconfigure)
+//	ack  != nil   close this channel once everything queued before it is written
+type outOp struct {
+	ts   time.Time
+	line []byte
+	cfg  *Config
+	ack  chan struct{}
+}
+
 // New returns a Sink fanning to stderr (the daemon passes os.Stderr) under cfg.
 // The file is opened lazily on the first line that needs it. A cfg with the
 // file OFF erases leftover segments right away — a daemon booting with the
@@ -226,15 +314,23 @@ func New(stderr io.Writer, cfg Config) *Sink {
 	if !cfg.ToFile {
 		purgeLogFiles(cfg.path(), PersistPath, TmpfsPath)
 	}
-	return &Sink{
+	s := &Sink{
 		cfg:       cfg,
+		outCfg:    cfg,
 		stderr:    stderr,
 		series:    make(map[string]*repeatSeries),
 		seriesLRU: list.New(),
+		outCh:     make(chan outOp, outQueueCap),
+		drainDone: make(chan struct{}),
 		now:       time.Now,
 		free:      freeBytes,
 		window:    repeatWindow,
 	}
+	// The channel is passed in rather than read from the field: Close NILS the
+	// field, and a goroutine that read it at its own leisure would race that write
+	// (and, if it lost, range over nil forever).
+	go s.drainLoop(s.outCh)
+	return s
 }
 
 // Write implements io.Writer for the log producers. It never returns an error
@@ -268,23 +364,27 @@ func (s *Sink) Write(p []byte) (int, error) {
 func (s *Sink) Reconfigure(cfg Config) {
 	cfg = cfg.normalized()
 	s.mu.Lock()
-	defer s.mu.Unlock()
 	if cfg == s.cfg {
+		s.mu.Unlock()
 		return
 	}
 	// Settle every series in progress under the OLD configuration: their
 	// summaries belong to the destination the swallowed lines were headed for.
 	s.flushAllSeriesLocked()
-	if cfg.path() != s.cfg.path() || !cfg.ToFile {
-		s.closeFileLocked()
-	}
-	if !cfg.ToFile {
-		purgeLogFiles(s.cfg.path(), cfg.path(), PersistPath, TmpfsPath)
-	}
-	s.suspended = false
-	s.lastProbe = time.Time{}
-	s.fileErr = false
 	s.cfg = cfg
+	// The file side of the swap — closing the old segment, erasing what a
+	// switched-off file must not leave behind, resetting the disk verdict — happens
+	// in the writer, IN ORDER, after every line queued under the old configuration.
+	// Otherwise a line written a microsecond ago would land in the new file, or in
+	// one that is about to be deleted.
+	queued := s.enqueueControlLocked(outOp{cfg: &cfg})
+	s.mu.Unlock()
+	// Wait for it to take effect, so a caller that reconfigures and then looks at
+	// the files sees the swap done. Bounded: a wedged writer costs the caller a
+	// delay, never the caller itself.
+	if queued {
+		s.Sync()
+	}
 }
 
 // Close flushes a pending partial line, emits the summaries of every still-open
@@ -293,21 +393,52 @@ func (s *Sink) Reconfigure(cfg Config) {
 // fires after Close is a no-op.
 func (s *Sink) Close() error {
 	s.mu.Lock()
-	defer s.mu.Unlock()
+	if s.closed {
+		s.mu.Unlock()
+		return nil
+	}
 	if len(s.buf) > 0 {
 		s.emitLocked(s.buf)
 		s.buf = nil
 	}
 	s.flushAllSeriesLocked()
 	s.closed = true
-	if s.file != nil {
-		err := s.file.Close()
-		s.file = nil
-		s.fileSize = 0
-		return err
-	}
+	s.stopRepeatTimerLocked()
+	ch := s.outCh
+	s.outCh = nil // no sender can hold it any more, so closing it below is safe
+	s.mu.Unlock()
+
+	if ch == nil {
 		return nil
 	}
+	close(ch)
+	select {
+	case <-s.drainDone:
+	case <-time.After(closeDrainTimeout):
+		// Shutdown must complete even when the log destination is the thing that
+		// is stuck. The queued tail is lost; saying so is the honest ending.
+		return fmt.Errorf("logsink: output blocked at shutdown; %d queued line(s) were not written", len(ch))
+	}
+	return s.closeErr
+}
+
+// Sync blocks until every line written so far has reached its destinations. It is
+// the barrier that makes the asynchronous writer observable — for a caller about
+// to read the log file, and for the tests. Bounded by outControlTimeout: a wedged
+// destination delays the caller, it does not capture it.
+func (s *Sink) Sync() {
+	s.mu.Lock()
+	ack := make(chan struct{})
+	queued := s.enqueueControlLocked(outOp{ack: ack})
+	s.mu.Unlock()
+	if !queued {
+		return
+	}
+	select {
+	case <-ack:
+	case <-time.After(outControlTimeout):
+	}
+}
 
 // --- internals (caller holds s.mu) -------------------------------------------
 
@@ -557,13 +688,128 @@ func repeatKey(line []byte) (string, bool) {
 	return string(b), false
 }
 
-// writeLineLocked stamps one line with the UTC wall clock and fans it out.
+// writeLineLocked hands one finished line to the writer. It stamps the line with
+// the wall clock HERE, not in the writer, so the timestamp is the moment the line
+// was produced rather than the moment the queue happened to reach it — a backlog
+// must not rewrite history.
+//
+// The line is COPIED: the caller's slice usually points into s.buf, which the very
+// next Write reuses.
 func (s *Sink) writeLineLocked(line []byte) {
 	if !s.cfg.ToSyslog && !s.cfg.ToFile {
 		return // fully off: the line is dropped, nowhere else to go
 	}
-	ts := s.now().UTC().Format(time.RFC3339)
-	if s.cfg.ToSyslog && s.stderr != nil {
+	s.enqueueLocked(outOp{ts: s.now(), line: append([]byte(nil), line...)})
+}
+
+// enqueueLocked offers one op to the writer WITHOUT ever blocking. A full queue
+// means the destination has stopped accepting bytes; the line is dropped and
+// counted, and the writer reports the count as soon as it moves again. Dropping
+// log lines is the price of a daemon that keeps answering — see the type comment.
+func (s *Sink) enqueueLocked(op outOp) {
+	if s.outCh == nil {
+		return // closed
+	}
+	select {
+	case s.outCh <- op:
+	default:
+		s.outDropped.Add(1)
+	}
+}
+
+// enqueueControlLocked posts a control op (a configuration swap, a barrier). These
+// may NOT be dropped — a lost Reconfigure would leave the writer on the old
+// destination for good — so it blocks, but only up to outControlTimeout. It
+// reports whether the op made it onto the queue.
+func (s *Sink) enqueueControlLocked(op outOp) bool {
+	if s.outCh == nil {
+		return false
+	}
+	select {
+	case s.outCh <- op:
+		return true
+	default:
+	}
+	timer := time.NewTimer(outControlTimeout)
+	defer timer.Stop()
+	select {
+	case s.outCh <- op:
+		return true
+	case <-timer.C:
+		return false
+	}
+}
+
+// --- the writer (the drain goroutine owns everything below) ------------------
+
+// drainLoop is the single goroutine that touches the destinations. It is the only
+// place in the package allowed to block on a write, and blocking here costs
+// nothing but log lines.
+func (s *Sink) drainLoop(ch chan outOp) {
+	defer close(s.drainDone)
+	for op := range ch {
+		s.handleOut(op)
+	}
+	if s.file != nil {
+		s.closeErr = s.file.Close()
+		s.file = nil
+		s.fileSize = 0
+	}
+}
+
+// handleOut performs one op. The three roles are handled in this order so that a
+// single op could carry more than one of them if a future caller needs it.
+func (s *Sink) handleOut(op outOp) {
+	if op.cfg != nil {
+		s.applyOutConfig(*op.cfg)
+	}
+	if op.line != nil {
+		s.reportDropsOut(op.ts)
+		s.fanOut(op.ts, op.line)
+	}
+	if op.ack != nil {
+		close(op.ack)
+	}
+}
+
+// applyOutConfig installs a new destination configuration at its place in the
+// stream: the old segment is closed, a switched-off file is erased at both
+// standard locations and the old one, and the disk verdict starts fresh (a
+// re-enabled or re-pointed file must not inherit a stale "suspended").
+func (s *Sink) applyOutConfig(cfg Config) {
+	if cfg.path() != s.outCfg.path() || !cfg.ToFile {
+		s.closeFileOut()
+	}
+	if !cfg.ToFile {
+		purgeLogFiles(s.outCfg.path(), cfg.path(), PersistPath, TmpfsPath)
+	}
+	s.suspended = false
+	s.lastProbe = time.Time{}
+	s.fileErr = false
+	s.outCfg = cfg
+}
+
+// reportDropsOut prints one notice per drop episode, the moment the writer is able
+// to write again. Silently losing lines is exactly the sort of dishonesty the
+// repeat-summary machinery above exists to avoid, so the gap is named.
+func (s *Sink) reportDropsOut(ts time.Time) {
+	dropped := s.outDropped.Load()
+	if dropped <= s.outReported {
+		return
+	}
+	lost := dropped - s.outReported
+	s.outReported = dropped
+	s.fanOut(ts, []byte(fmt.Sprintf("WARN logsink: dropped %d log line(s) — the log destination stopped accepting writes (total %d)", lost, dropped)))
+}
+
+// fanOut stamps one line with the UTC wall clock and writes it to the enabled
+// destinations. This is where the process may block; nothing else waits on it.
+func (s *Sink) fanOut(at time.Time, line []byte) {
+	if !s.outCfg.ToSyslog && !s.outCfg.ToFile {
+		return // fully off: the line is dropped, nowhere else to go
+	}
+	ts := at.UTC().Format(time.RFC3339)
+	if s.outCfg.ToSyslog && s.stderr != nil {
 		out := make([]byte, 0, len(ts)+1+len(line)+1)
 		out = append(out, ts...)
 		out = append(out, ' ')
@@ -571,7 +817,7 @@ func (s *Sink) writeLineLocked(line []byte) {
 		out = append(out, '\n')
 		_, _ = s.stderr.Write(out)
 	}
-	if s.cfg.ToFile {
+	if s.outCfg.ToFile {
 		// The file gets the line with ANSI colour codes stripped: the producers
 		// colour for a terminal, and a downloaded .log full of escape bytes is
 		// broken UX. The syslog copy is passed through untouched (unchanged
@@ -582,22 +828,22 @@ func (s *Sink) writeLineLocked(line []byte) {
 		out = append(out, ' ')
 		out = append(out, clean...)
 		out = append(out, '\n')
-		s.fileWriteLocked(out)
+		s.fileWriteOut(out)
 	}
 }
 
-// fileWriteLocked appends one stamped line to the active segment, rotating
-// when the segment budget (MaxKB/2) would be exceeded.
-func (s *Sink) fileWriteLocked(out []byte) {
-	if s.cfg.Persist && !s.diskOKLocked() {
+// fileWriteOut appends one stamped line to the active segment, rotating when the
+// segment budget (MaxKB/2) would be exceeded.
+func (s *Sink) fileWriteOut(out []byte) {
+	if s.outCfg.Persist && !s.diskOKOut() {
 		return
 	}
-	if s.file == nil && !s.openLocked() {
+	if s.file == nil && !s.openOut() {
 		return
 	}
-	segCap := int64(s.cfg.MaxKB) * 1024 / 2
+	segCap := int64(s.outCfg.MaxKB) * 1024 / 2
 	if s.fileSize > 0 && s.fileSize+int64(len(out)) > segCap {
-		s.rotateLocked()
+		s.rotateOut()
 		if s.file == nil {
 			return
 		}
@@ -607,24 +853,24 @@ func (s *Sink) fileWriteLocked(out []byte) {
 	if err != nil {
 		if !s.fileErr {
 			s.fileErr = true
-			s.warnLocked("write " + s.cfg.path() + ": " + err.Error() + " — file logging degraded")
+			s.warnOut("write " + s.outCfg.path() + ": " + err.Error() + " — file logging degraded")
 		}
 		return
 	}
 	s.fileErr = false
 }
 
-// openLocked opens (creating if needed) the active segment for append and
-// learns its current size so the rotation budget survives a daemon restart.
-func (s *Sink) openLocked() bool {
-	path := s.cfg.path()
+// openOut opens (creating if needed) the active segment for append and learns its
+// current size so the rotation budget survives a daemon restart.
+func (s *Sink) openOut() bool {
+	path := s.outCfg.path()
 	if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
-		s.warnOpenFailLocked(err)
+		s.warnOpenFailOut(err)
 		return false
 	}
 	f, err := os.OpenFile(path, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0o644)
 	if err != nil {
-		s.warnOpenFailLocked(err)
+		s.warnOpenFailOut(err)
 		return false
 	}
 	var size int64
@@ -637,20 +883,20 @@ func (s *Sink) openLocked() bool {
 	return true
 }
 
-func (s *Sink) warnOpenFailLocked(err error) {
+func (s *Sink) warnOpenFailOut(err error) {
 	if s.fileErr {
 		return
 	}
 	s.fileErr = true
-	s.warnLocked("open " + s.cfg.path() + ": " + err.Error() + " — file logging unavailable")
+	s.warnOut("open " + s.outCfg.path() + ": " + err.Error() + " — file logging unavailable")
 }
 
-// rotateLocked replaces "<path>.1" with the full active segment and starts a
-// fresh one. If the rename is impossible the active segment is truncated in
-// place — losing the older half is strictly better than growing past the cap.
-func (s *Sink) rotateLocked() {
-	path := s.cfg.path()
-	s.closeFileLocked()
+// rotateOut replaces "<path>.1" with the full active segment and starts a fresh
+// one. If the rename is impossible the active segment is truncated in place —
+// losing the older half is strictly better than growing past the cap.
+func (s *Sink) rotateOut() {
+	path := s.outCfg.path()
+	s.closeFileOut()
 	// os.Rename replaces an existing target on POSIX but not on Windows (dev
 	// host / tests), so drop the old .1 explicitly first.
 	_ = os.Remove(path + ".1")
@@ -658,16 +904,16 @@ func (s *Sink) rotateLocked() {
 		if f, terr := os.OpenFile(path, os.O_TRUNC|os.O_CREATE|os.O_WRONLY, 0o644); terr == nil {
 			s.file = f
 			s.fileSize = 0
-			s.warnLocked("rotate " + path + ": " + err.Error() + " — truncated the active segment instead")
+			s.warnOut("rotate " + path + ": " + err.Error() + " — truncated the active segment instead")
 			return
 		}
-		s.warnLocked("rotate " + path + ": " + err.Error() + " — file logging unavailable")
+		s.warnOut("rotate " + path + ": " + err.Error() + " — file logging unavailable")
 		return
 	}
-	s.openLocked()
+	s.openOut()
 }
 
-func (s *Sink) closeFileLocked() {
+func (s *Sink) closeFileOut() {
 	if s.file != nil {
 		_ = s.file.Close()
 		s.file = nil
@@ -691,7 +937,7 @@ func purgeLogFiles(paths ...string) {
 	}
 }
 
-// diskOKLocked is the persistent-path guard: require the full log cap PLUS a
+// diskOKOut is the persistent-path guard: require the full log cap PLUS a
 // fixed floor to be free before writing flash, re-probing at most once a
 // minute. An undeterminable free count fails OPEN for logging (the file is the
 // thing being asked for; refusing it on a stat error helps nobody) — the cap
@@ -699,40 +945,40 @@ func purgeLogFiles(paths ...string) {
 // stats/diskfree_unix.go: on a ~33 MB-free rootfs, filling the disk takes down
 // far more than logging, so under pressure the log yields, warns once, and the
 // daemon lives.
-func (s *Sink) diskOKLocked() bool {
+func (s *Sink) diskOKOut() bool {
 	nowT := s.now()
 	if !s.lastProbe.IsZero() && nowT.Sub(s.lastProbe) < diskProbeEvery {
 		return !s.suspended
 	}
 	s.lastProbe = nowT
-	freeB, ok := s.free(filepath.Dir(s.cfg.path()))
+	freeB, ok := s.free(filepath.Dir(s.outCfg.path()))
 	if !ok {
 		s.suspended = false
 		return true
 	}
-	need := uint64(s.cfg.MaxKB)*1024 + diskFloorBytes
+	need := uint64(s.outCfg.MaxKB)*1024 + diskFloorBytes
 	if freeB < need {
 		if !s.suspended {
 			s.suspended = true
-			s.closeFileLocked()
-			s.warnLocked(fmt.Sprintf("only %d KiB free at %s (need %d KiB) — suspending persistent file logging",
-				freeB/1024, filepath.Dir(s.cfg.path()), need/1024))
+			s.closeFileOut()
+			s.warnOut(fmt.Sprintf("only %d KiB free at %s (need %d KiB) — suspending persistent file logging",
+				freeB/1024, filepath.Dir(s.outCfg.path()), need/1024))
 		}
 		return false
 	}
 	if s.suspended {
 		s.suspended = false
-		s.warnLocked("disk space recovered — resuming persistent file logging")
+		s.warnOut("disk space recovered — resuming persistent file logging")
 	}
 	return true
 }
 
-// warnLocked reports a sink-internal problem on the syslog half only (the file
+// warnOut reports a sink-internal problem on the syslog half only (the file
 // half is, in every caller, the thing that is failing). With ToSyslog off there
 // is nowhere left the operator allowed us to speak — the warning is dropped,
 // which is exactly what "fully silent" means.
-func (s *Sink) warnLocked(msg string) {
-	if !s.cfg.ToSyslog || s.stderr == nil {
+func (s *Sink) warnOut(msg string) {
+	if !s.outCfg.ToSyslog || s.stderr == nil {
 		return
 	}
 	ts := s.now().UTC().Format(time.RFC3339)

shater/logsink/logsink_test.go

@@ -3,6 +3,7 @@ package logsink
 import (
 	"bytes"
 	"fmt"
+	"io"
 	"os"
 	"path/filepath"
 	"regexp"
@@ -214,6 +215,8 @@ func TestReconfigureSwitchesPathAndToggles(t *testing.T) {
 	_, _ = s.Write([]byte("goes to a\n"))
 	s.Reconfigure(cfgB)
 	_, _ = s.Write([]byte("goes to b\n"))
+	// The writer is asynchronous; Sync is the barrier that makes it observable.
+	s.Sync()
 	if got := readFile(t, cfgB.Path); !strings.Contains(got, "goes to b") || strings.Contains(got, "goes nowhere") {
 		t.Fatalf("b.log content wrong: %q", got)
 	}
@@ -252,6 +255,7 @@ func TestDiskGuardSuspendsAndResumes(t *testing.T) {
 	}
 
 	_, _ = s.Write([]byte("while low 1\nwhile low 2\n"))
+	s.Sync()
 	if _, err := os.Stat(cfg.Path); !os.IsNotExist(err) {
 		t.Fatalf("file written despite low disk (err=%v)", err)
 	}
@@ -637,6 +641,7 @@ func TestRepeatTableOverflowReportsEviction(t *testing.T) {
 	_, _ = s.Write([]byte(engLine(999, "ERROR", "one key too many")))
 
 	want := "repeated 1 time (repeat table full): ERROR chain-000 is down"
+	s.Sync()
 	got := payloads(t, stderr.String())
 	found := false
 	for _, l := range got {
@@ -784,6 +789,7 @@ func TestRepeatFatalNeverSuppressed(t *testing.T) {
 		_, _ = s2.Write([]byte(engLine(sec, "ERROR", "about to die")))
 	}
 	_, _ = s2.Write([]byte(engLine(4, "FATAL", "engine is gone")))
+	s2.Sync()
 	got := payloads(t, stderr2.String())
 	want := []string{
 		strings.TrimSuffix(engLine(1, "ERROR", "about to die"), "\n"),
@@ -916,3 +922,189 @@ func TestNewFileOffPurgesLeftovers(t *testing.T) {
 		}
 	}
 }
+
+// --- a wedged destination must not freeze the process ------------------------
+
+// blockingWriter is the procd stderr pipe once logd stopped reading it: the first
+// write enters and never returns until the test lets it. Nothing about this is
+// exotic — a pipe holds 64 KiB and then blocks its writer, forever, with no error
+// and no deadline.
+type blockingWriter struct {
+	entered   chan struct{}
+	release   chan struct{}
+	enterOnce sync.Once
+	relOnce   sync.Once
+}
+
+func newBlockingWriter() *blockingWriter {
+	return &blockingWriter{entered: make(chan struct{}), release: make(chan struct{})}
+}
+
+func (w *blockingWriter) Write(p []byte) (int, error) {
+	w.enterOnce.Do(func() { close(w.entered) })
+	<-w.release
+	return len(p), nil
+}
+
+func (w *blockingWriter) unblock() { w.relOnce.Do(func() { close(w.release) }) }
+
+// TestWedgedDestinationNeverBlocksLogging is the freeze regression.
+//
+// The sink used to take s.mu on entry to Write and still hold it while writing to
+// stderr. Under procd that write is a write to a pipe, so a reader that stops
+// draining it stops the writer — permanently, since the daemon has no deadline on
+// fd 2. Every goroutine that logged then queued on s.mu: the engine, every panel
+// handler, the apply path and the signal loop. The daemon stayed alive to
+// `kill -0` and answered nothing, which is exactly what
+// cmd/shaterd/ctlclient.go's timeouts describe running into.
+//
+// The contract this pins: with the destination wedged, logging still RETURNS.
+// Lines are lost and counted — that is the intended sacrifice — but nothing that
+// merely wanted to log is captured by the log.
+func TestWedgedDestinationNeverBlocksLogging(t *testing.T) {
+	w := newBlockingWriter()
+	cfg := fileCfg(t, true, true, 0)
+	s := New(w, cfg)
+	// Releasing the destination is not enough: the writer then drains its backlog,
+	// which RE-CREATES the log file. Registered as a cleanup — and therefore run
+	// BEFORE t.TempDir's own, which was registered first and so runs last — so the
+	// writer is finished before the directory is removed, on the failing paths too.
+	t.Cleanup(func() {
+		w.unblock()
+		select {
+		case <-s.drainDone:
+		case <-time.After(10 * time.Second):
+			t.Error("the writer never finished after the destination recovered")
+		}
+	})
+
+	// Wedge it. The write goes through a goroutine of its own because the whole
+	// point of the defect is that this call did not come back: in the broken sink
+	// it parks inside stderr.Write while holding the mutex every other logger
+	// needs, so a test that made this call from the main flow would simply hang
+	// here instead of reporting what it found.
+	go func() { _, _ = s.Write([]byte("the line that wedges the pipe\n")) }()
+	select {
+	case <-w.entered:
+	case <-time.After(10 * time.Second):
+		t.Fatal("the sink never wrote to stderr at all")
+	}
+
+	// Everything else in the process keeps logging. Enough lines to overrun the
+	// queue several times over, from several goroutines, exactly as the daemon
+	// does it.
+	const writers = 4
+	done := make(chan struct{})
+	go func() {
+		defer close(done)
+		var wg sync.WaitGroup
+		for g := 0; g < writers; g++ {
+			wg.Add(1)
+			go func(g int) {
+				defer wg.Done()
+				for i := 0; i < outQueueCap; i++ {
+					_, _ = s.Write([]byte(engLine(g*outQueueCap+i, "ERROR", fmt.Sprintf("worker %d line %d", g, i))))
+				}
+			}(g)
+		}
+		wg.Wait()
+	}()
+	select {
+	case <-done:
+	case <-time.After(20 * time.Second):
+		t.Fatal("a logging goroutine blocked on a wedged log destination — under procd this is the whole daemon freezing")
+	}
+
+	// The overrun was real, and it is accounted for rather than silent.
+	if dropped := s.outDropped.Load(); dropped == 0 {
+		t.Fatal("nothing was dropped although the queue was overrun many times — the front must be bounded")
+	}
+
+	// Shutdown completes even while the destination is still wedged: Close is
+	// bounded, and it says what it could not write.
+	closed := make(chan error, 1)
+	go func() { closed <- s.Close() }()
+	select {
+	case err := <-closed:
+		if err == nil {
+			t.Fatal("Close reported success although the queued tail was never written")
+		}
+		if !strings.Contains(err.Error(), "output blocked") {
+			t.Fatalf("Close error = %v, want it to name the blocked output", err)
+		}
+	case <-time.After(closeDrainTimeout + 10*time.Second):
+		t.Fatal("Close hung on a wedged log destination — shutdown must not depend on the log being drainable")
+	}
+}
+
+// TestWedgedDestinationRecoveryReportsTheGap: when the destination starts
+// accepting again, the writer says how many lines the gap swallowed. A silent
+// hole in the log is the same dishonesty the repeat summaries exist to avoid.
+func TestWedgedDestinationRecoveryReportsTheGap(t *testing.T) {
+	w := newBlockingWriter()
+	var recorded syncBuffer
+	cfg := fileCfg(t, true, false, 0)
+	s := New(&chainWriter{first: w, then: &recorded}, cfg)
+	// Releasing the destination is not enough: the writer then drains its backlog,
+	// which RE-CREATES the log file. Registered as a cleanup — and therefore run
+	// BEFORE t.TempDir's own, which was registered first and so runs last — so the
+	// writer is finished before the directory is removed, on the failing paths too.
+	t.Cleanup(func() {
+		w.unblock()
+		select {
+		case <-s.drainDone:
+		case <-time.After(10 * time.Second):
+			t.Error("the writer never finished after the destination recovered")
+		}
+	})
+
+	go func() { _, _ = s.Write([]byte(engLine(0, "ERROR", "wedge"))) }()
+	select {
+	case <-w.entered:
+	case <-time.After(10 * time.Second):
+		t.Fatal("the sink never wrote to stderr at all")
+	}
+	for i := 1; i <= 2*outQueueCap; i++ {
+		_, _ = s.Write([]byte(engLine(i, "ERROR", fmt.Sprintf("line %d", i))))
+	}
+	if s.outDropped.Load() == 0 {
+		t.Fatal("the queue was not overrun; the test proves nothing")
+	}
+
+	w.unblock()
+	s.Sync()
+	if got := recorded.String(); !strings.Contains(got, "dropped") {
+		t.Fatalf("recovery did not report the gap; stderr tail: %q", lastLines(got, 3))
+	}
+	_ = s.Close()
+}
+
+// chainWriter sends the first write to one writer and everything after it to
+// another, so a test can wedge the destination and still observe what comes out
+// once it recovers.
+type chainWriter struct {
+	first io.Writer
+	then  io.Writer
+	once  sync.Once
+	used  bool
+	mu    sync.Mutex
+}
+
+func (c *chainWriter) Write(p []byte) (int, error) {
+	c.mu.Lock()
+	first := !c.used
+	c.used = true
+	c.mu.Unlock()
+	if first {
+		return c.first.Write(p)
+	}
+	return c.then.Write(p)
+}
+
+func lastLines(s string, n int) string {
+	lines := strings.Split(strings.TrimSuffix(s, "\n"), "\n")
+	if len(lines) > n {
+		lines = lines[len(lines)-n:]
+	}
+	return strings.Join(lines, "\n")
+}

shater/model/dnsintercept_test.go

@@ -0,0 +1,105 @@
+package model
+
+// Tests for the `dns_intercept` default flip (D24): forcing ALL LAN plaintext
+// :53 — including the queries a client sends to the ROUTER, which is what DHCP
+// hands out — into the engine is now the DEFAULT, not an opt-in.
+//
+// Two properties are pinned here, and they pull in opposite directions:
+//
+//	1. a config that never mentions the option (every install written before it
+//	   existed, and the state a hand-edited file is usually in) must come back ON;
+//	2. an EXPLICIT `option dns_intercept '0'` must stay OFF — including across a
+//	   WriteUCI->ReadUCI round-trip, where a bool omitted at false would be re-read
+//	   as the seed and silently flip the operator's decision back on.
+//
+// (2) is the reason render.go emits booleans always. It is the exact trap that
+// makes a default-true bool different from a default-false one, so it gets a test
+// of its own rather than riding on the generic round-trip fixture.
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+// TestDNSInterceptDefaultOn: the seed and an option-less config both say ON.
+func TestDNSInterceptDefaultOn(t *testing.T) {
+	if !DefaultGlobals().DNSIntercept {
+		t.Fatal("DefaultGlobals().DNSIntercept = false, want true (D24: intercept is opt-out)")
+	}
+	m, err := ParseUCIExport("package shater\n\nconfig globals 'globals'\n\toption enabled '1'\n")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !m.Globals.DNSIntercept {
+		t.Fatal("a config with no dns_intercept option parsed as OFF; an absent option must fall back to the ON seed")
+	}
+}
+
+// TestDNSInterceptExplicitOffPreserved: the operator's opt-out survives both the
+// parse (over an ON seed) and the render->parse round-trip.
+func TestDNSInterceptExplicitOffPreserved(t *testing.T) {
+	m, err := ParseUCIExport("package shater\n\nconfig globals 'globals'\n" +
+		"\toption enabled '1'\n\toption dns_intercept '0'\n")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if m.Globals.DNSIntercept {
+		t.Fatal("explicit dns_intercept '0' was overwritten by the ON seed")
+	}
+
+	rendered := RenderUCIExport(m)
+	if !strings.Contains(rendered, "option dns_intercept '0'") {
+		t.Fatalf("render must emit the explicit '0' (an omitted bool would be re-read as ON):\n%s", rendered)
+	}
+	back, err := ParseUCIExport(rendered)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if back.Globals.DNSIntercept {
+		t.Fatal("dns_intercept '0' did not survive the WriteUCI->ReadUCI round-trip — the opt-out would be silently re-enabled on the next save")
+	}
+}
+
+// TestDNSInterceptExplicitOnParses: the ON spelling is read as ON too (a seed
+// that happens to agree must not be the only reason the value is true).
+func TestDNSInterceptExplicitOnParses(t *testing.T) {
+	m, err := ParseUCIExport("package shater\n\nconfig globals 'globals'\n\toption dns_intercept '1'\n")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !m.Globals.DNSIntercept {
+		t.Fatal("explicit dns_intercept '1' parsed as OFF")
+	}
+}
+
+// TestShippedConfigEnablesDNSIntercept reads the file the package actually
+// installs. /etc/config/shater is a CONFFILE: it is written once, on first
+// install, and never replaced on upgrade — so a fresh install's DNS posture is
+// decided by this file's literal text, not by DefaultGlobals. The two must agree,
+// and only a test that reads the shipped bytes can say that they do.
+//
+// It also pins the inert shipping posture (enabled '0') the file's own header
+// promises, since both facts live in the same section.
+func TestShippedConfigEnablesDNSIntercept(t *testing.T) {
+	path := filepath.Join("..", "..", "openwrt", "shater-core", "files", "etc", "config", "shater")
+	raw, err := os.ReadFile(path)
+	if err != nil {
+		t.Skipf("shipped config not readable from this checkout (%v)", err)
+	}
+	text := string(raw)
+	if !strings.Contains(text, "option dns_intercept '1'") {
+		t.Error("the shipped /etc/config/shater must set dns_intercept '1' explicitly: a fresh install reads this file, and an operator who later opts out must see the option they are flipping")
+	}
+	m, err := ParseUCIExport(text)
+	if err != nil {
+		t.Fatalf("shipped config does not parse: %v", err)
+	}
+	if !m.Globals.DNSIntercept {
+		t.Error("shipped config parses with DNSIntercept off")
+	}
+	if m.Globals.Enabled {
+		t.Error("shipped config must stay inert (enabled '0'): a fresh install may not touch connectivity")
+	}
+}

shater/model/model.go

@@ -212,7 +212,33 @@ type Globals struct {
 	GeositeIndexURL string // GitHub git-trees URL used to suggest categories; "" = no suggestions
 	GeoipIndexURL   string
 	DNSFilter       bool // master enable for the DNS bl/allow-list filter (D15); default false (opt-in)
-	DNSIntercept    bool // force ALL LAN plaintext DNS (:53) through the engine, incl. router-addressed queries; default false (opt-in)
+	// DNSIntercept forces ALL LAN plaintext DNS (:53) through the engine, INCLUDING
+	// queries addressed to the router itself. Default TRUE (opt-out) — see D24.
+	//
+	// It has to be the default, because the alternative is inverted: without it the
+	// nft prerouting :53 divert is gated (netplane/nft.go) and a router-addressed
+	// query falls through `fib daddr type local accept` into dnsmasq and out to the
+	// ISP in the clear — so the client with STANDARD settings (DNS = the router, as
+	// DHCP hands it out) leaked past the filter, the blocklists, the per-device
+	// rules and the resolver detour, while the client that hard-coded 8.8.8.8 "to
+	// bypass the router" was caught by the ordinary tproxy catch-all. Obedient
+	// clients leaked; evaders did not.
+	//
+	// Consequences of ON, all of them intended:
+	//   - .lan and the RFC6303 private reverse zones are preserved by a synthetic
+	//     server pointed at dnsmasq on 127.0.0.1:53 plus a prepended domain_suffix
+	//     rule (generate/dns.go). That preservation needs at least one `config
+	//     resolver`; with none, buildDNS emits no DNS plane at all and the engine
+	//     falls back to its built-in `local` transport, which reads /etc/resolv.conf
+	//     (127.0.0.1 = dnsmasq) — local names still resolve, but nothing is filtered.
+	//   - while the engine is DOWN, router-addressed :53 is NOT blacked out: the
+	//     holding plane hooks `forward` only and dnsmasq keeps answering (unfiltered,
+	//     plaintext to the ISP). Queries aimed at an EXTERNAL resolver are dropped
+	//     with the rest of the LAN's forwarded traffic. See netplane/nft.go.
+	//   - an EXPLICIT `option dns_intercept '0'` still wins: render.go always emits
+	//     the bool, so an operator's opt-out survives the WriteUCI->ReadUCI round-trip
+	//     and is never silently re-enabled by this seed.
+	DNSIntercept bool
 	BlockDoH     bool // block known public DoH resolvers (:443) so clients fall back to plaintext :53 (which the engine catches); default false (opt-in)
 	// GroupHealth is the master-switch of OUR background group health-probing (the
 	// scheduled probing that keeps a group's member delays fresh, see
@@ -294,6 +320,13 @@ const (
 // The operational-log knobs are seeded to syslog ON + file ON + tmpfs + 2048 KiB: a
 // config written before they existed keeps today's behaviour (lines reach logread) and
 // additionally gains the bounded tmpfs file the /api/log download reads.
+//
+// DNSIntercept is seeded ON (opt-out, D24): a config that never mentions
+// `dns_intercept` — every install predating the option — starts routing
+// router-addressed :53 into the engine, because the opt-in default protected only
+// the clients that were trying to evade the router (see the field comment). An
+// EXPLICIT `option dns_intercept '0'` parses over this seed and is preserved:
+// render.go always emits the bool, so opting out is a decision the config keeps.
 func DefaultGlobals() Globals {
 	return Globals{
 		Enabled:              true,
@@ -307,6 +340,7 @@ func DefaultGlobals() Globals {
 		FwmarkBase:           0x2000,
 		TableBase:            0x2000,
 		GroupHealth:          true,
+		DNSIntercept:         true,
 		StatsBackend:         "memory",
 		StatsRingSize:        200,
 		StatsTimelineMinutes: 60,

shater/netplane/apply.go

@@ -12,6 +12,7 @@ import (
 	"net/netip"
 	"os/exec"
 	"strings"
+	"sync"
 	"time"
 
 	"github.com/sagernet/sing-box/shater/model"
@@ -134,6 +135,23 @@ func addRouting(mark, table uint32, ipv6 bool) error {
 		fams = append(fams, "-6")
 	}
 	for _, fam := range fams {
+		// Already intact? Then do NOTHING for this family.
+		//
+		// The reconciliation below is idempotent BY del-then-add, which means it
+		// opens a window with no fwmark rule installed, and any packet diverted
+		// during it misses the `local default dev lo` table and is eaten by the
+		// fail-closed forward drop. That is an acceptable cost when something
+		// actually has to be rebuilt — and pure damage when nothing does.
+		//
+		// It matters more now that RoutingPresent also fails on a broken per-egress
+		// binding (see below): an egress that cannot be installed at all — a wg
+		// interface that is down and stays down — makes every one-minute reconcile
+		// call back into here. Without this guard each of those would tear the MAIN
+		// tproxy rule down and put it back, once a minute, forever, for a fault that
+		// has nothing to do with it.
+		if mainRoutingPresentFam(fam, mark, table) {
+			continue
+		}
 		run(fam, "rule", "del", "fwmark", fmt.Sprintf("0x%x", mark), "lookup", fmt.Sprintf("%d", table))
 		if out, err := execCommand("ip", fam, "rule", "add", "fwmark",
 			fmt.Sprintf("0x%x", mark), "lookup", fmt.Sprintf("%d", table)).CombinedOutput(); err != nil {
@@ -156,12 +174,100 @@ func removeRouting(mark, table uint32) {
 	}
 }
 
+// egressBinding is one (family, mark, table) policy-routing binding that
+// addEgressRouting INTENDED to install for a named egress. See
+// rememberEgressBindings for why the intent, and not the outcome, is what gets
+// recorded.
+type egressBinding struct {
+	fam   string // "-4" / "-6"
+	mark  uint32
+	table uint32
+}
+
+// egressBindings is what the last addEgressRouting run set out to install, and it
+// is the ONLY thing that tells RoutingPresent which per-egress rules and tables
+// have to exist right now.
+//
+// It has to be remembered rather than derived: RoutingPresent is handed a
+// model.Globals, and the number of egresses — the one input that decides which
+// marks and tables exist — lives on model.Model, not on Globals. Recomputing it
+// from the live system is not possible either: an egress whose rule has been
+// deleted leaves nothing behind to count.
+//
+// The record is always populated by the time its answer can matter: applyLocked
+// evaluates `!nftCurrent || !RoutingPresent(...)`, and nftCurrent can only be true
+// after an apply in THIS process has already run ApplyRoutingWithWarnings.
+var (
+	egressBindingsMu sync.Mutex
+	egressBindings   []egressBinding
+)
+
+// rememberEgressBindings records what a run of addEgressRouting was supposed to
+// install, whether or not each individual `ip` call succeeded.
+//
+// INTENT, not outcome, on purpose. A binding that failed to install (the egress
+// device does not exist yet — `ifdown wg0`, a tunnel that comes up late) is
+// exactly the one that must keep RoutingPresent false, so the next reconcile
+// tries again and the egress repairs itself the moment its interface returns.
+// Recording only the successes would make a failed egress permanently invisible
+// to the presence check, which is the shape of the defect this fixes.
+func rememberEgressBindings(b []egressBinding) {
+	egressBindingsMu.Lock()
+	egressBindings = b
+	egressBindingsMu.Unlock()
+}
+
+// snapshotEgressBindings returns a copy of the recorded bindings.
+func snapshotEgressBindings() []egressBinding {
+	egressBindingsMu.Lock()
+	defer egressBindingsMu.Unlock()
+	return append([]egressBinding(nil), egressBindings...)
+}
+
+// runIP performs one `ip` mutation and returns a reason (command + stderr) when it
+// fails. Used for the mutations whose failure is a routing hole; the del/flush
+// half of the del-then-add idiom keeps using the ignore-errors form, because
+// "there was nothing to delete" is the normal case there and not a fault.
+func runIP(args ...string) error {
+	out, err := execCommand("ip", args...).CombinedOutput()
+	if err != nil {
+		if txt := strings.TrimSpace(string(out)); txt != "" {
+			return fmt.Errorf("`ip %s` failed: %v: %s", strings.Join(args, " "), err, txt)
+		}
+		return fmt.Errorf("`ip %s` failed: %v", strings.Join(args, " "), err)
+	}
+	return nil
+}
+
 // addEgressRouting realises the policy-routing half of an interface/tunnel egress
 // (the generator emits the SO_BINDTODEVICE+SO_MARK outbound; this binds the mark
 // to a table whose default route leaves via the egress device). Idempotent.
+//
+// # Every failing `ip` call is reported
+//
+// This used to run ALL of its mutations through a `_ = ...Run()` helper, so an
+// egress bound to an interface that did not exist at apply time — `ifdown wg0`, a
+// tunnel that has not come up yet, a renamed device — produced a completely
+// successful apply: no error, no warning, a green egress in the panel, and every
+// node, group and rule bound to it marked for a routing table that was never
+// created. The mark then finds no table of its own, falls through to the main
+// table and leaves over the ordinary WAN with the router's real address. That is
+// the leak the egress exists to prevent, delivered silently.
+//
+// The rule/route ADDs are therefore checked and warned about individually, with
+// the egress name and the reason `ip` gave. The del/flush calls stay
+// ignore-errors: they are the "make this idempotent" half and they legitimately
+// fail when there is nothing there yet.
+//
+// A failure is a WARNING and not a returned error deliberately. Returning would
+// abort the whole apply (the caller propagates it), leaving the sysctl and
+// conntrack steps that follow un-run over one broken uplink — the household-wide
+// punishment for a scoped fault that this codebase refuses everywhere else. The
+// warning is worded so apply/warnings.go grades it critical, which is what it is.
 func addEgressRouting(m *model.Model) ([]string, error) {
 	run := func(args ...string) { _ = execCommand("ip", args...).Run() }
 	var warnings []string
+	var bindings []egressBinding
 	for i, eg := range m.Egresses {
 		t := strings.ToLower(eg.Type)
 		if (t != "interface" && t != "tunnel") || eg.Interface == "" {
@@ -175,24 +281,50 @@ func addEgressRouting(m *model.Model) ([]string, error) {
 			fams = append(fams, "-6")
 		}
 		for _, fam := range fams {
-			run(fam, "rule", "del", "fwmark", fmt.Sprintf("0x%x", mark), "lookup", fmt.Sprintf("%d", table))
-			run(fam, "rule", "add", "fwmark", fmt.Sprintf("0x%x", mark), "lookup", fmt.Sprintf("%d", table))
-			run(fam, "route", "flush", "table", fmt.Sprintf("%d", table))
+			bindings = append(bindings, egressBinding{fam: fam, mark: mark, table: table})
+			markArg, tableArg := fmt.Sprintf("0x%x", mark), fmt.Sprintf("%d", table)
+
+			run(fam, "rule", "del", "fwmark", markArg, "lookup", tableArg)
+			if err := runIP(fam, "rule", "add", "fwmark", markArg, "lookup", tableArg); err != nil {
+				// The `kind "name": message` prefix is the shape apply's warning
+				// normaliser parses (entityRe), so this lands as an egress-scoped,
+				// named warning in the panel rather than an anonymous line.
+				warnings = append(warnings, fmt.Sprintf(
+					"egress %q: its %s policy rule (fwmark %s -> table %d) could not be installed, so this egress "+
+						"is NOT applied: every node, group and rule bound to it is still marked, finds no routing "+
+						"table of its own, falls through to the main table and leaves over the plain WAN with your "+
+						"real IP address. Reason: %v",
+					eg.Name, famLabel(fam), markArg, table, err))
+				continue
+			}
+			run(fam, "route", "flush", "table", tableArg)
+
 			// A gateway'd interface (WAN) needs `via <gw>`; a point-to-point tunnel
 			// (wg/awg) has no gateway and routes straight out the device.
-			if gw := egressGateway(fam, eg.Interface, dev); gw != "" {
-				run(fam, "route", "add", "default", "via", gw, "dev", dev, "table", fmt.Sprintf("%d", table))
+			gw := egressGateway(fam, eg.Interface, dev)
+			var rerr error
+			if gw != "" {
+				rerr = runIP(fam, "route", "add", "default", "via", gw, "dev", dev, "table", tableArg)
+			} else {
+				rerr = runIP(fam, "route", "add", "default", "dev", dev, "table", tableArg)
+			}
+			if rerr != nil {
+				warnings = append(warnings, fmt.Sprintf(
+					"egress %q: its %s default route could not be installed into table %d, so that table is EMPTY "+
+						"and this egress is NOT applied: every node, group and rule bound to it is marked for an "+
+						"empty table, falls through to the main table and leaves over the plain WAN with your real "+
+						"IP address. Check that interface %q (device %s) exists and is up. Reason: %v",
+					eg.Name, famLabel(fam), table, eg.Interface, dev, rerr))
+				continue
+			}
+			if gw != "" {
 				continue
 			}
-			run(fam, "route", "add", "default", "dev", dev, "table", fmt.Sprintf("%d", table))
 			// No nexthop AND not a point-to-point device: the route just installed says
 			// "everything is on the local segment", which for any address outside this
 			// subnet is a guaranteed failure. The egress is configured, reports as
 			// applied, and cannot carry a single packet off-link — say so.
 			if !isPointToPoint(dev) {
-				// The `kind "name": message` prefix is the shape apply's warning
-				// normaliser parses (entityRe), so this lands as an egress-scoped,
-				// named warning in the panel rather than an anonymous line.
 				warnings = append(warnings, fmt.Sprintf(
 					"egress %q: no %s gateway could be found for interface %q (device %s) "+
 						"by any means, so its routing table sends traffic straight onto the "+
@@ -204,6 +336,7 @@ func addEgressRouting(m *model.Model) ([]string, error) {
 			}
 		}
 	}
+	rememberEgressBindings(bindings)
 	return warnings, nil
 }
 
@@ -227,6 +360,10 @@ func uciGatewayOption(fam string) string {
 // block (safe when nothing is set up).
 func removeEgressRouting(m *model.Model) {
 	run := func(args ...string) { _ = execCommand("ip", args...).Run() }
+	// Nothing is installed any more, so nothing may be claimed as installed: a
+	// stale record would make RoutingPresent report a torn-down plane as broken
+	// rather than as absent, and the main-pair check answers that question already.
+	rememberEgressBindings(nil)
 	for i := range m.Egresses {
 		mark := EgressMark(m.Globals, i)
 		table := EgressTable(m.Globals, i)
@@ -403,30 +540,123 @@ func isPointToPoint(dev string) bool {
 // reconcile cannot repair, because a reconcile is exactly what consults this
 // function. A presence check must cover everything its Apply counterpart
 // installs, or the idempotent fast-path becomes a trap.
+//
+// # The per-egress bindings are checked too
+//
+// The same sentence applies to the OTHER half of ApplyRouting, which this check
+// used to be completely blind to: addEgressRouting installs a `fwmark -> table`
+// rule plus a default route in that table for EVERY interface/tunnel egress, and
+// neither EgressMark nor EgressTable was mentioned here at all.
+//
+// That blindness was a permanent leak, not a cosmetic gap. An egress rides an
+// interface (a second WAN, a wg/awg tunnel), and `ifdown wg0` or a `network
+// restart` makes the kernel delete every route through that device — including
+// the default route in the egress's own table. The ip RULE survives, so the marked
+// traffic still gets sent to that table, finds it empty, falls through to the main
+// table and leaves over the ordinary WAN with the router's real address. The
+// one-minute reconcile then asked this function whether routing was present, was
+// told yes on the strength of the main tproxy pair alone, and skipped
+// ApplyRouting — so nothing ever restored the route. The box reported plane=full
+// with zero warnings while the tunnel it was built for was bypassed, and only a
+// config edit or a daemon restart could clear it.
+//
+// Which bindings must exist comes from the record addEgressRouting keeps (see
+// egressBindings): Globals alone cannot say how many egresses there are, and a
+// deleted rule leaves nothing on the system to count.
 func RoutingPresent(g model.Globals) bool {
-	wantRule := fmt.Sprintf("fwmark 0x%x", effFwmark(g))
-	table := fmt.Sprintf("%d", effTable(g))
+	mark, table := effFwmark(g), effTable(g)
 	fams := []string{"-4"}
 	if g.IPv6 {
 		fams = append(fams, "-6")
 	}
 	for _, fam := range fams {
+		if !mainRoutingPresentFam(fam, mark, table) {
+			return false
+		}
+	}
+	return egressRoutingPresent()
+}
+
+// mainRoutingPresentFam reports whether BOTH halves of the main tproxy plane are
+// installed for one family: the fwmark rule and the `local default dev lo` route
+// inside the table it points at.
+func mainRoutingPresentFam(fam string, mark, table uint32) bool {
 	out, err := execCommand("ip", fam, "rule", "show").Output()
-		if err != nil || !strings.Contains(string(out), wantRule) {
+	if err != nil || !fwmarkRulePresent(string(out), mark) {
 		return false
 	}
 	// `ip -4 route show table N` prints "local default dev lo scope host";
 	// the v6 form is "local default dev lo metric 1024 pref medium". Matching
 	// the route TYPE + destination covers both without pinning the trailing
 	// attributes, which differ by family and iproute2 version.
-		rout, rerr := execCommand("ip", fam, "route", "show", "table", table).Output()
-		if rerr != nil || !strings.Contains(string(rout), "local default") {
+	rout, rerr := execCommand("ip", fam, "route", "show", "table", fmt.Sprintf("%d", table)).Output()
+	return rerr == nil && strings.Contains(string(rout), "local default")
+}
+
+// egressRoutingPresent reports whether every per-egress binding the last apply set
+// out to install is still there: the rule AND a default route in its table.
+//
+// The route half is the one that matters most — see RoutingPresent's essay — but
+// both are checked, for the same reason the main pair checks both: they are
+// removed by independent commands and either can go missing on its own.
+func egressRoutingPresent() bool {
+	bindings := snapshotEgressBindings()
+	if len(bindings) == 0 {
+		return true // no interface/tunnel egress configured: nothing else to install
+	}
+	rules := map[string]string{} // family -> `ip -N rule show` output, read once
+	for _, b := range bindings {
+		out, cached := rules[b.fam]
+		if !cached {
+			raw, err := execCommand("ip", b.fam, "rule", "show").Output()
+			if err != nil {
+				return false
+			}
+			out = string(raw)
+			rules[b.fam] = out
+		}
+		if !fwmarkRulePresent(out, b.mark) {
+			return false
+		}
+		// Any default route will do: `default via <gw> dev X` for a gateway'd
+		// uplink, `default dev X` for a point-to-point tunnel. What must never pass
+		// is an EMPTY table, which is what an ifdown leaves behind.
+		rout, err := execCommand("ip", b.fam, "route", "show", "table", fmt.Sprintf("%d", b.table)).Output()
+		if err != nil || !strings.Contains(string(rout), "default") {
 			return false
 		}
 	}
 	return true
 }
 
+// fwmarkRulePresent reports whether `ip rule show` output carries a rule for
+// EXACTLY this mark.
+//
+// The match is anchored on the right because a plain substring test confuses
+// marks that share a prefix: with a small fwmark_base the main divert mark (say
+// 0x1) is a prefix of the first egress mark (0x101), so "the main rule is
+// installed" could be answered by an egress rule that has nothing to do with it.
+// `ip` always prints the mark as a whole token — "fwmark 0x101 lookup 8210", or
+// "fwmark 0x101/0xff" when a mask is in play (never ours) — so requiring a
+// separator (or end of line) after it is sufficient and version-independent.
+func fwmarkRulePresent(out string, mark uint32) bool {
+	want := fmt.Sprintf("fwmark 0x%x", mark)
+	for _, line := range strings.Split(out, "\n") {
+		for i := 0; ; {
+			j := strings.Index(line[i:], want)
+			if j < 0 {
+				break
+			}
+			rest := line[i+j+len(want):]
+			if rest == "" || rest[0] == ' ' || rest[0] == '\t' || rest[0] == '\r' {
+				return true
+			}
+			i += j + len(want)
+		}
+	}
+	return false
+}
+
 // IfaceDevice resolves a UCI interface name (e.g. "lan") to its actual L3 device
 // (e.g. "br-lan") for nft iifname matching / SO_BINDTODEVICE — bridges/VLANs have
 // device != name, so matching the raw UCI name would silently intercept nothing.

shater/netplane/egressgw_test.go

@@ -24,6 +24,10 @@ func (f *fakeNet) install(t *testing.T) {
 	t.Helper()
 	orig := execCommand
 	t.Cleanup(func() { execCommand = orig })
+	// addEgressRouting records what it installed for RoutingPresent (see
+	// egressBindings in apply.go). That record is package state, so it must not
+	// leak out of a test into the RoutingPresent cases in the other files.
+	t.Cleanup(func() { rememberEgressBindings(nil) })
 	execCommand = func(name string, arg ...string) *exec.Cmd {
 		out := ""
 		switch {

shater/netplane/egressplane_test.go

@@ -0,0 +1,287 @@
+package netplane
+
+// Per-egress policy routing: it must be VERIFIED by the presence check, and its
+// installation must be REPORTED when it fails.
+//
+// Both defects here produce the same end state and it is the worst one this
+// project has: an egress that the panel shows as configured and applied, while
+// the traffic bound to it is marked for a routing table that is empty or absent,
+// falls through to the main table, and leaves over the ordinary WAN with the
+// router's real address. Neither state raised anything — no error, no warning —
+// and neither could be repaired by a reconcile.
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"strings"
+	"testing"
+
+	"github.com/sagernet/sing-box/shater/model"
+)
+
+// egressPlaneNet is a canned view of the box's routing state plus a switch for
+// making chosen `ip` mutations fail, so a test can drive both the presence check
+// and the failure reporting without touching the real system.
+type egressPlaneNet struct {
+	rules  map[string]string // family ("-4"/"-6") -> `ip -N rule show` output
+	routes map[string]string // "<family> <table>"  -> `ip -N route show table N` output
+	link   map[string]string // device             -> `ip link show dev D` output
+	ubus   map[string]string // interface          -> `ubus call ... status` JSON
+	failIf func(name string, arg []string) bool
+	calls  []string // every intercepted invocation, joined
+}
+
+func (f *egressPlaneNet) install(t *testing.T) {
+	t.Helper()
+	orig := execCommand
+	t.Cleanup(func() { execCommand = orig })
+	// addEgressRouting records what it installed in package state; never let that
+	// leak into another test's RoutingPresent.
+	rememberEgressBindings(nil)
+	t.Cleanup(func() { rememberEgressBindings(nil) })
+
+	execCommand = func(name string, arg ...string) *exec.Cmd {
+		f.calls = append(f.calls, name+" "+strings.Join(arg, " "))
+		out := ""
+		switch {
+		case name == "ubus" && len(arg) >= 2 && arg[0] == "call":
+			out = f.ubus[strings.TrimPrefix(arg[1], "network.interface.")]
+		case name == "ip" && len(arg) >= 3 && arg[0] == "link" && arg[1] == "show":
+			out = f.link[arg[len(arg)-1]]
+		case name == "ip" && len(arg) >= 2 && arg[1] == "rule" && arg[2] == "show":
+			out = f.rules[arg[0]]
+		case name == "ip" && len(arg) >= 5 && arg[1] == "route" && arg[2] == "show" && arg[3] == "table":
+			out = f.routes[arg[0]+" "+arg[4]]
+		}
+		fail := f.failIf != nil && f.failIf(name, arg)
+		cs := append([]string{"-test.run=TestEgressPlaneHelperProcess", "--", name}, arg...)
+		cmd := exec.Command(os.Args[0], cs...)
+		env := append(os.Environ(), "GO_WANT_HELPER_PROCESS=1", "GO_HELPER_STDOUT="+out)
+		if fail {
+			env = append(env, "GO_HELPER_FAIL=1")
+		}
+		cmd.Env = env
+		return cmd
+	}
+}
+
+// TestEgressPlaneHelperProcess is the canned-output / canned-failure child.
+func TestEgressPlaneHelperProcess(t *testing.T) {
+	if os.Getenv("GO_WANT_HELPER_PROCESS") != "1" {
+		return
+	}
+	if os.Getenv("GO_HELPER_FAIL") == "1" {
+		os.Stderr.WriteString("Cannot find device \"wg0\"\n")
+		os.Exit(2)
+	}
+	os.Stdout.WriteString(os.Getenv("GO_HELPER_STDOUT"))
+	os.Exit(0)
+}
+
+// egressPlaneGlobals pins the marks/tables the cases below hard-code.
+func egressPlaneGlobals() model.Globals {
+	return model.Globals{FwmarkBase: 0x2000, TableBase: 0x2000}
+}
+
+// wgEgressModel is one point-to-point tunnel egress on wg0 — the shape that
+// produces no gateway warning of its own, so anything a test sees is the fault it
+// is testing.
+func wgEgressModel() *model.Model {
+	return &model.Model{
+		Globals:  egressPlaneGlobals(),
+		Egresses: []model.Egress{{Name: "vpn", Type: "tunnel", Interface: "wgvpn"}},
+	}
+}
+
+func wgEgressNet() *egressPlaneNet {
+	return &egressPlaneNet{
+		ubus: map[string]string{"wgvpn": `{"up":true,"l3_device":"wg0","route":[]}`},
+		link: map[string]string{"wg0": "5: wg0: <POINTOPOINT,NOARP,UP,LOWER_UP> mtu 1420"},
+	}
+}
+
+// DEFECT 2. RoutingPresent decided the whole policy-routing plane was intact from
+// the MAIN tproxy pair alone: EgressMark and EgressTable were not mentioned in it
+// even once. So `ifdown wg0` (or a `network restart`), which makes the kernel drop
+// every route through that device — including the default route inside the
+// egress's own table — left a state where:
+//
+//   - the ip rule still sends the egress mark to table 8208,
+//   - table 8208 is empty,
+//   - so the marked traffic falls through to the main table and leaves over the
+//     plain WAN with the router's real address,
+//   - and the one-minute reconcile asked this function, was told "present", and
+//     never re-ran ApplyRouting. Permanent, at plane=full, with zero warnings.
+//
+// The main pair is deliberately healthy in every case below, so only the per-egress
+// half can decide the answer.
+func TestRoutingPresentSeesEgressTables(t *testing.T) {
+	const (
+		mainRule   = "32765:\tfrom all fwmark 0x2000 lookup 8192"
+		egressRule = "32764:\tfrom all fwmark 0x2100 lookup 8208"
+		mainRoute  = "local default dev lo scope host"
+		egressRte  = "default dev wg0 scope link"
+	)
+	cases := []struct {
+		name       string
+		rules      string // `ip -4 rule show`
+		egressTbl  string // `ip -4 route show table 8208`
+		wantPresen bool
+	}{
+		{"complete", mainRule + "\n" + egressRule, egressRte, true},
+		// THE REGRESSION: ifdown wg0 emptied the egress table, the rule survived.
+		{"egress table emptied by ifdown", mainRule + "\n" + egressRule, "", false},
+		// The other half: the rule itself went away.
+		{"egress rule gone", mainRule, egressRte, false},
+	}
+
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			f := wgEgressNet()
+			f.install(t)
+
+			// Record the bindings the way production does: through a real apply.
+			if _, err := addEgressRouting(wgEgressModel()); err != nil {
+				t.Fatalf("addEgressRouting: %v", err)
+			}
+
+			f.rules = map[string]string{"-4": c.rules}
+			f.routes = map[string]string{
+				"-4 8192": mainRoute,
+				"-4 8208": c.egressTbl,
+			}
+			if got := RoutingPresent(egressPlaneGlobals()); got != c.wantPresen {
+				t.Fatalf("RoutingPresent = %v, want %v.\n"+
+					"A presence check blind to the per-egress table lets a reconcile skip ApplyRouting "+
+					"forever while the egress-marked traffic leaves over the plain WAN.",
+					got, c.wantPresen)
+			}
+		})
+	}
+}
+
+// A model with no interface/tunnel egress must still report present on a healthy
+// main pair — the egress half may only ever ADD a reason to re-apply.
+func TestRoutingPresentUnaffectedWithoutEgresses(t *testing.T) {
+	f := &egressPlaneNet{
+		rules:  map[string]string{"-4": "32765:\tfrom all fwmark 0x2000 lookup 8192"},
+		routes: map[string]string{"-4 8192": "local default dev lo scope host"},
+	}
+	f.install(t)
+	if _, err := addEgressRouting(&model.Model{Globals: egressPlaneGlobals()}); err != nil {
+		t.Fatalf("addEgressRouting: %v", err)
+	}
+	if !RoutingPresent(egressPlaneGlobals()) {
+		t.Fatal("a healthy main pair with no egresses must report present")
+	}
+}
+
+// fwmarkRulePresent must not confuse marks that share a prefix. With a small
+// fwmark_base the main divert mark is a literal prefix of the first egress mark,
+// and a plain strings.Contains would answer "the main rule is installed" with an
+// egress rule that has nothing to do with it.
+func TestFwmarkRulePresentIsExact(t *testing.T) {
+	const out = "32764:\tfrom all fwmark 0x101 lookup 273"
+	if fwmarkRulePresent(out, 0x1) {
+		t.Error("fwmark 0x1 must NOT be matched by a rule for fwmark 0x101")
+	}
+	if !fwmarkRulePresent(out, 0x101) {
+		t.Error("fwmark 0x101 must be matched by its own rule")
+	}
+	if fwmarkRulePresent("32764:\tfrom all fwmark 0x101/0xff lookup 273", 0x101) {
+		t.Error("a masked rule is a different rule and must not match")
+	}
+}
+
+// DEFECT 3. addEgressRouting ran every mutation through `_ = exec...Run()`, so an
+// egress bound to a device that does not exist at apply time — `ifdown wg0`, a
+// tunnel that has not come up yet, a renamed interface — reported a completely
+// successful apply: no error, no warning, a green egress in the panel, and an
+// empty routing table underneath it. Everything bound to that egress then leaves
+// over the ordinary WAN with the router's real address.
+func TestEgressRouteAddFailureIsReported(t *testing.T) {
+	f := wgEgressNet()
+	f.failIf = func(name string, arg []string) bool {
+		return name == "ip" && len(arg) >= 3 && arg[1] == "route" && arg[2] == "add"
+	}
+	f.install(t)
+
+	warns, err := addEgressRouting(wgEgressModel())
+	if err != nil {
+		t.Fatalf("a broken egress must not abort the whole apply: %v", err)
+	}
+	if len(warns) != 1 {
+		t.Fatalf("a failing `ip route add` must produce exactly one operator warning, got %d: %v",
+			len(warns), warns)
+	}
+	w := warns[0]
+	// The `kind "name":` prefix is what apply/warnings.go parses into Section/Name,
+	// and the consequence clauses are what grade it critical there.
+	for _, want := range []string{
+		`egress "vpn":`,
+		"is NOT applied",
+		"leaves over the plain WAN with your real IP address",
+		"wgvpn",
+		"wg0",
+		"Cannot find device", // the reason `ip` itself gave
+	} {
+		if !strings.Contains(w, want) {
+			t.Errorf("warning is missing %q:\n%s", want, w)
+		}
+	}
+}
+
+// The same contract for the OTHER mutation: without its ip rule the egress mark is
+// not bound to any table at all.
+func TestEgressRuleAddFailureIsReported(t *testing.T) {
+	f := wgEgressNet()
+	f.failIf = func(name string, arg []string) bool {
+		return name == "ip" && len(arg) >= 3 && arg[1] == "rule" && arg[2] == "add"
+	}
+	f.install(t)
+
+	warns, err := addEgressRouting(wgEgressModel())
+	if err != nil {
+		t.Fatalf("a broken egress must not abort the whole apply: %v", err)
+	}
+	if len(warns) != 1 {
+		t.Fatalf("a failing `ip rule add` must produce exactly one operator warning, got %d: %v",
+			len(warns), warns)
+	}
+	for _, want := range []string{`egress "vpn":`, "is NOT applied", "leaves over the plain WAN with your real IP address"} {
+		if !strings.Contains(warns[0], want) {
+			t.Errorf("warning is missing %q:\n%s", want, warns[0])
+		}
+	}
+	// A rule that could not be installed means the table binding does not exist;
+	// pushing a default route into an unreachable table would only hide that.
+	for _, c := range f.calls {
+		if strings.Contains(c, "route add default") {
+			t.Errorf("no default route may be installed once the rule add failed: %q", c)
+		}
+	}
+}
+
+// A failed install must keep RoutingPresent FALSE, so the next reconcile tries
+// again and the egress repairs itself the moment its interface comes back. This is
+// why the binding record holds INTENT and not outcome.
+func TestFailedEgressKeepsRoutingAbsent(t *testing.T) {
+	f := wgEgressNet()
+	f.failIf = func(name string, arg []string) bool {
+		return name == "ip" && len(arg) >= 3 && arg[1] == "route" && arg[2] == "add"
+	}
+	f.install(t)
+	if _, err := addEgressRouting(wgEgressModel()); err != nil {
+		t.Fatalf("addEgressRouting: %v", err)
+	}
+
+	f.failIf = nil
+	f.rules = map[string]string{"-4": "32765:\tfrom all fwmark 0x2000 lookup 8192\n" +
+		fmt.Sprintf("32764:\tfrom all fwmark 0x%x lookup 8208", EgressMark(egressPlaneGlobals(), 0))}
+	f.routes = map[string]string{"-4 8192": "local default dev lo scope host", "-4 8208": ""}
+	if RoutingPresent(egressPlaneGlobals()) {
+		t.Fatal("an egress whose route could not be installed must keep the plane reported ABSENT, " +
+			"so the next reconcile retries it")
+	}
+}

shater/netplane/untunnelable.go

@@ -11,18 +11,36 @@ package netplane
 // the tunnel at all. The forward chain therefore has to decide what happens to
 // them, and until now the answer was a blanket drop.
 //
-// # Why the blanket drop was wrong
+// # `block` blocks. It did not, and that was the bug.
 //
-// The drop is justified by "we cannot tunnel this packet and we will not let it
-// out with the client's real address". That justification only holds for
-// destinations the routing rules actually send THROUGH the tunnel. When a rule
-// routes a destination DIRECT, the client's real address already reaches it over
-// TCP — so dropping ICMP to that same destination hides nothing and only breaks
-// diagnostics. The old behaviour over-blocked: with a `ru-direct` rule sending
-// Russian addresses direct, those addresses still could not be pinged.
+// There is an argument that the drop is only justified for destinations the
+// routing rules actually send THROUGH the tunnel: when a rule routes a
+// destination DIRECT, the client's real address already reaches it over TCP, so
+// dropping ICMP to that same destination hides nothing and only breaks
+// diagnostics. That argument is sound about ICMP echo. It was applied to `block`
+// as a whole, and there it was wrong twice over:
 //
-// So: drop untunnelable traffic exactly where an equivalent TCP flow would have
-// been tunnelled, and let it out where that flow would have gone direct.
+//   - IT DEGENERATED. The commonest configuration on this router is "tunnel what
+//     is blocked, send the rest direct", which makes the routing DEFAULT direct —
+//     so EVERY destination is direct, so `block` allowed everything, everywhere.
+//     The most private of the three rungs was bit-for-bit identical to the most
+//     permissive one, and only the daemon log said so.
+//   - IT IS NOT THE SAME DISCLOSURE. "That host already sees your address over
+//     TCP" holds for a ping and does not hold for ESP, AH or GRE. A client-run
+//     IPsec or PPTP tunnel to a directly-routed server is a STANDING second
+//     tunnel, carrying arbitrary traffic past ours for as long as it stays up,
+//     under a peer we neither route nor filter. Letting that out is the exact
+//     exposure the middle rung was created to separate from "answering a ping",
+//     and `block` was granting it silently.
+//
+// So `block` now drops every untunnelable protocol, wherever it was going, with
+// no reference to the routing rules at all. Its promise no longer depends on a
+// configuration the operator can change without noticing. The price is real and
+// is listed on the constants below; it is a price the owner chose knowingly, on
+// the grounds that this router does not do ping and does not do IPTV.
+//
+// The destination walk below survives and serves `icmp`, where the ICMP half of
+// the argument does hold.
 //
 // # What "exactly" can and cannot mean
 //
@@ -48,17 +66,49 @@ import (
 // The three form a ladder, and each rung is a distinct, explicable amount of
 // disclosure rather than an arbitrary midpoint:
 //
-//	block  — untunnelable traffic is allowed ONLY to destinations the routing
-//	         rules send direct anyway. No destination learns your address that
-//	         would not have learned it from ordinary TCP. The default.
-//	icmp   — additionally allows ICMP echo to TUNNELLED destinations, so ping and
-//	         traceroute work everywhere. The host you ping learns your real
-//	         address; nothing else does, and nothing persistent is established.
+//	block  — EVERY untunnelable protocol is dropped, wherever it was going. The
+//	         default, and the only rung whose promise does not depend on how the
+//	         routing rules happen to be written.
+//	icmp   — block, plus ICMP echo to every destination, so ping and traceroute
+//	         work. The host pinged learns the real address; nothing else does, and
+//	         nothing persistent is established. The remaining protocols are also
+//	         let out toward destinations the routing rules send DIRECT — see the
+//	         plan walk below — because that host already has the address from
+//	         ordinary TCP.
 //	direct — allows every untunnelable protocol everywhere, including ESP/AH/GRE
 //	         to tunnelled destinations. That is a client-run VPN operating in
 //	         parallel to ours with the real address, carrying arbitrary traffic
 //	         for as long as it stays up — a different kind of exposure from
 //	         answering a ping, which is why it is not folded into `icmp`.
+//
+// # What `block` costs the LAN, exactly
+//
+// Everything below is LAN-ingress traffic bound for a PUBLIC address; the local
+// plane (LAN-to-LAN, link-local, ICMPv6 ND/RA, multicast to the router) is
+// accepted earlier in the forward chain and is untouched by any of this.
+//
+//   - ICMPv4 and ICMPv6 ECHO: `ping` and Windows `tracert` from a LAN device stop
+//     answering for every public address. Linux/macOS `traceroute` defaults to UDP
+//     probes, which are tunnelled — so it still prints hops, but they are the
+//     tunnel's path, not the client's.
+//   - ICMP ERRORS raised BY a LAN host toward a public peer, including
+//     fragmentation-needed. Path-MTU discovery for tunnelled flows is unaffected
+//     (those terminate on the router, which raises its own errors from the output
+//     hook); only a LAN host's errors on a directly-routed flow are lost.
+//   - ESP (50) and AH (51): a device's own IPsec VPN, when it runs RAW ESP. IKE
+//     (UDP 500) and NAT-T ESP (UDP 4500) are UDP and go through the tunnel like
+//     anything else, so an IPsec client behind NAT — the usual case — is not
+//     affected by this at all. WireGuard and OpenVPN-UDP are UDP likewise.
+//   - GRE (47): PPTP's data plane, and plain GRE tunnels. PPTP's control channel
+//     is TCP 1723 and is tunnelled, so the connection appears to establish and
+//     then carries nothing.
+//   - SCTP (132): rare from a home LAN. WebRTC data channels are SCTP over
+//     DTLS/UDP and are therefore unaffected.
+//   - IGMP (2): a LAN client's multicast group joins, where they are routed
+//     rather than answered by the router itself. Note the multicast STREAM is
+//     WAN-ingress and never matched by these rules, and multicast UDP from the LAN
+//     is already dropped by the fail-closed guard whatever this policy says — so
+//     IPTV was not working through this router before the change either.
 const (
 	UntunnelableBlock  = "block"
 	UntunnelableICMP   = "icmp"
@@ -247,9 +297,13 @@ func untunnelableSets(plan *UntunnelablePlan) string {
 // They must sit AFTER the local-plane accepts (LAN-to-LAN, link-local, ICMPv6 ND)
 // and BEFORE the fail-closed drops.
 //
-// plan may be nil, which means "no destination knowledge" — every destination is
-// then treated as tunnelled, which is the conservative reading and reproduces the
-// behaviour from before destinations were taken into account.
+// plan is read by `icmp` and by nothing else — the other two rungs are
+// unconditional, and reading it there is exactly the bug this function used to
+// have. A nil plan means "no destination knowledge" (the holding plane, or an
+// engine that has not resolved its lists yet): every destination is then treated
+// as tunnelled, which is the conservative reading, so `icmp` degrades to plain
+// echo-only. apply.untunnelablePlanFor therefore builds no plan at all except for
+// `icmp`, and this function must stay correct if one is handed to it anyway.
 func untunnelableRules(g model.Globals, iif string, plan *UntunnelablePlan) string {
 	if iif == "" {
 		return ""
@@ -257,19 +311,31 @@ func untunnelableRules(g model.Globals, iif string, plan *UntunnelablePlan) stri
 	policy := EffectiveUntunnelable(g)
 	var sb strings.Builder
 
-	// `direct` short-circuits the whole plan: everything untunnelable leaves,
-	// wherever it was going.
-	if policy == UntunnelableDirect {
+	// Both ends of the ladder short-circuit the plan, in opposite directions, and
+	// neither may consult it.
+	switch policy {
+	case UntunnelableDirect:
+		// Everything untunnelable leaves, wherever it was going.
 		sb.WriteString("\t\t" + iif + " " + untunnelableFilter + " accept\n")
 		return sb.String()
+	case UntunnelableBlock:
+		// Nothing leaves. Emitting NO line is how that is said: every untunnelable
+		// packet falls through to the fail-closed drops the caller writes next.
+		//
+		// This is the whole fix. `block` used to walk the plan like `icmp` does and
+		// therefore inherited its default — which, for the ordinary "tunnel the
+		// blocked list, send the rest direct" configuration, is ALLOW. The most
+		// private rung was rendering the same `l4proto != { tcp, udp } accept` as
+		// the most permissive one. There is deliberately no `plan` in scope for
+		// this branch: the promise is unconditional, so no routing knowledge may
+		// enter it.
+		return ""
 	}
 
 	// `icmp` lets echo out ahead of the destination walk, so ping and traceroute
 	// work even toward tunnelled destinations.
-	if policy == UntunnelableICMP {
 	sb.WriteString("\t\t" + iif + " ip protocol icmp icmp type { echo-request, echo-reply } accept\n")
 	sb.WriteString("\t\t" + iif + " icmpv6 type { echo-request, echo-reply } accept\n")
-	}
 
 	if plan == nil {
 		// No knowledge of where anything routes: nothing is provably direct, so
@@ -284,12 +350,25 @@ func untunnelableRules(g model.Globals, iif string, plan *UntunnelablePlan) stri
 		if mt.Allow {
 			verb = "accept"
 		}
+		// A step is emitted PER FAMILY, and a step that named addresses only in the
+		// other family is not applicable to this one. Both halves of the predicate
+		// have to obey that, or the missing clause silently widens the line:
+		//
+		//	dst — skip; without `ip daddr @set` the line would match every destination.
+		//	src — skip; without `ip saddr @set` the line would match every SOURCE. A
+		//	      rule whose source_ip_cidr held only IPv6 prefixes used to render an
+		//	      IPv4 line with no saddr clause at all, i.e. an accept for the whole
+		//	      LAN from a rule scoped to a handful of v6 clients. "Scoped at all"
+		//	      is the union of the two families, exactly as the catch-all collapse
+		//	      in apply/untunnelable.go reads it.
+		srcScoped := len(mt.Src4) > 0 || len(mt.Src6) > 0
 		emit := func(fam int, dstSet, srcSet string, dst, src []string) {
-			// A step that named destinations for this family but has none is not
-			// applicable to it; skip rather than widening to "any".
 			if !mt.AnyDst && len(dst) == 0 {
 				return
 			}
+			if srcScoped && len(src) == 0 {
+				return
+			}
 			var b strings.Builder
 			b.WriteString("\t\t" + iif + " " + untunnelableFilter + " ")
 			if len(src) > 0 {

shater/panel/api.go

@@ -384,8 +384,50 @@ var (
 		cmd.Stdout = w
 		return cmd.Run()
 	}
+	// logSyncTimeout bounds how long a download waits for the log sink's barrier
+	// (Server.SetLogSync). See syncLogSink for why the wait is bounded at all.
+	//
+	// Why 2s: it is the sink's OWN control budget (logsink.outControlTimeout) —
+	// past one such budget the barrier has given up internally anyway, so waiting
+	// longer buys nothing. A healthy writer drains the queue in microseconds, so
+	// this is a ceiling nobody pays, not a delay added to every download.
+	logSyncTimeout = 2 * time.Second
 )
 
+// syncLogSink waits for the daemon's log sink to have WRITTEN everything it has
+// accepted so far, so the download below sees the lines the operator just caused.
+// A no-op when no sink is wired (SetLogSync unset).
+//
+// The wait is bounded, and that bound is the point. The sink was made
+// asynchronous precisely so a wedged log destination (a full stderr pipe whose
+// reader stopped draining) can no longer freeze everything that logs. A barrier
+// that waited indefinitely would hand that same power back to it, one HTTP
+// handler further along: /api/log would become the new place the daemon hangs.
+// So a stuck writer costs the download a bounded delay and it then streams what
+// IS on disk — degraded, like every other honest fallback in this handler.
+//
+// The barrier runs in its own goroutine so that giving up is really giving up:
+// abandoning a call we cannot cancel. logsink.Sink.Sync is itself bounded, so the
+// goroutine ends on its own; a seam that never returns would leak one goroutine
+// per request, which is a contract for test seams to respect, not a lock to take.
+func (s *Server) syncLogSink() {
+	fn := s.logSync
+	if fn == nil {
+		return
+	}
+	done := make(chan struct{})
+	go func() {
+		defer close(done)
+		fn()
+	}()
+	timer := time.NewTimer(logSyncTimeout)
+	defer timer.Stop()
+	select {
+	case <-done:
+	case <-timer.C:
+	}
+}
+
 // handleLog → GET /api/log?range=1d|3d|all: download shaterd's OPERATIONAL log
 // (the daemon's own lines + the embedded engine's, as written by shater/logsink)
 // as a text/plain attachment. CONTRACT (the panel is built against this):
@@ -398,6 +440,11 @@ var (
 //     Content-Disposition: attachment; filename="shaterd-<range>-<YYYYMMDD>.log"
 //     (date in UTC). The body is STREAMED line by line — never buffered whole —
 //     from the sink's segments, oldest first (<path>.1 then <path>).
+//   - the answer contains every line the daemon had ACCEPTED into the log when
+//     the request arrived: the sink writes asynchronously, so the handler first
+//     runs its barrier (Server.SetLogSync) to flush what is still queued. The
+//     barrier is bounded — a wedged log destination costs a short delay, never
+//     the request.
 //   - honesty fallbacks: turning file logging OFF made the sink DELETE the
 //     saved segments (see shater/logsink), so with the toggle off and syslog on
 //     the best effort is a `logread -e shater` scrape prefixed with an
@@ -434,6 +481,14 @@ func (s *Server) handleLog(w http.ResponseWriter, r *http.Request) {
 		g = m.Globals
 	}
 
+	// The sink writes asynchronously, so the newest lines — the ones this
+	// download exists for — may still be queued. Flush them to their destination
+	// before reading it. Bounded; see syncLogSink. Skipped when logging is fully
+	// off: there is then nothing queued and nothing to read.
+	if g.LogToFile || g.LogToSyslog {
+		s.syncLogSink()
+	}
+
 	w.Header().Set("Content-Type", "text/plain; charset=utf-8")
 	w.Header().Set("Cache-Control", "no-store")
 	w.Header().Set("Content-Disposition",
@@ -1491,13 +1546,22 @@ type groupHealthResponse struct {
 // box materialised:
 //
 //	chains[].hops = [{index,tag,kind,exit,state,delay_ms,age_seconds,selected,
-//	                  total,tested,alive,dead,untested}...]
+//	                  total,tested,alive,dead,untested,blocked_by?}...]
 //
 //   - hops is L1..Ln in wire order (index is 1-based); the entry with exit=true
 //     is the last hop, where traffic leaves to the internet. Each hop's numbers
 //     measure the chain PREFIX up to and including that hop — the observatory
 //     dials the hop wrappers — so a dead hop N with alive hops 1..N-1 localises
 //     the failure to hop N's own leg.
+//   - the walk is ORDERED and stops at the first dead hop. Hop N is dialled
+//     THROUGH hops 1..N-1, so probing it across a dead hop 2 would measure hop 2
+//     again and say nothing about hop N. Everything behind the first dead hop is
+//     therefore left undialled and reported state="untested" with
+//     blocked_by={index,tag} naming the hop that stopped the walk; its counters
+//     are 0/0/0/total and its delay_ms/age_seconds are 0/-1. blocked_by is
+//     OMITTED on every hop that was actually measured, and a hop carrying it is
+//     never a fault of its own — the fault is at blocked_by.index. It follows
+//     that a dead hop with a LIVE hop behind it can no longer be reported.
 //   - kind is "node" (one measurement: total=1, selected empty) or "group" (a
 //     roll-up of the hop's member copies, with the same counter invariants as a
 //     group: tested == alive+dead, alive+dead+untested == total; selected is

shater/panel/log_test.go

@@ -14,6 +14,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/sagernet/sing-box/shater/logsink"
 	"github.com/sagernet/sing-box/shater/model"
 )
 
@@ -211,3 +212,115 @@ func TestLogFileOffIgnoresLeftoverSegments(t *testing.T) {
 		t.Fatalf("scrape output missing:\n%s", body)
 	}
 }
+
+// --- the sink barrier (Server.SetLogSync) ------------------------------------
+
+// slowWriter stands in for the destination the sink's writer goroutine owns
+// (under procd: the stderr pipe procd relays to logread). Every write takes
+// `d`, which is what puts the just-written line demonstrably IN FLIGHT while the
+// download runs — the sink hands lines to that goroutine and returns at once.
+type slowWriter struct{ d time.Duration }
+
+func (w slowWriter) Write(p []byte) (int, error) {
+	time.Sleep(w.d)
+	return len(p), nil
+}
+
+// A line logged immediately before the request must be IN the download. The sink
+// writes asynchronously, so without the barrier the download opens the file
+// while the line is still queued and serves a truncated log — silently, with a
+// 200 — losing exactly the last moments the operator downloaded the log to read.
+func TestLogDownloadIncludesJustQueuedLines(t *testing.T) {
+	g := model.DefaultGlobals() // file on, syslog on
+	path := withLogSeams(t, g, "")
+
+	// A sink whose writer goroutine is busy for 300ms on the syslog half — long
+	// enough that the file half provably has not happened yet when the request
+	// arrives, short enough to stay well inside logSyncTimeout.
+	sink := logsink.New(slowWriter{d: 300 * time.Millisecond}, logsink.Config{
+		ToSyslog: true, ToFile: true, Path: path,
+	})
+	t.Cleanup(func() { _ = sink.Close() })
+
+	s := newTestServer(t)
+	s.SetLogSync(sink.Sync)
+	srv := httptest.NewServer(s.Handler())
+	defer srv.Close()
+	cookie := login(t, srv, s) // before the write: the handshake must not absorb the delay
+
+	if _, err := io.WriteString(sink, "INFO[0001] the line the operator came for\n"); err != nil {
+		t.Fatal(err)
+	}
+	resp := getDaemonLog(t, srv, cookie, "?range=all")
+	body, _ := io.ReadAll(resp.Body)
+	resp.Body.Close()
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("got %d, want 200 (%s)", resp.StatusCode, body)
+	}
+	if !strings.Contains(string(body), "the line the operator came for") {
+		t.Fatalf("the download lost the line queued just before it:\n%s", body)
+	}
+}
+
+// A wedged log destination must cost the download a bounded delay, not the
+// download. The whole point of the asynchronous sink is that a stuck writer
+// stops nothing but its own goroutine; a barrier that waited forever would just
+// move the hang into /api/log.
+func TestLogDownloadSurvivesWedgedSink(t *testing.T) {
+	g := model.DefaultGlobals()
+	withLogSeams(t, g, "2026-07-23T08:00:00Z INFO already on disk\n")
+
+	orig := logSyncTimeout
+	logSyncTimeout = 150 * time.Millisecond
+	t.Cleanup(func() { logSyncTimeout = orig })
+
+	// A barrier that never returns on its own, exactly like a Sync behind a
+	// writer blocked in write(2) on a full pipe nobody drains.
+	release := make(chan struct{})
+	t.Cleanup(func() { close(release) })
+
+	s := newTestServer(t)
+	s.SetLogSync(func() { <-release })
+	srv := httptest.NewServer(s.Handler())
+	defer srv.Close()
+	cookie := login(t, srv, s)
+
+	start := time.Now()
+	resp := getDaemonLog(t, srv, cookie, "?range=all")
+	body, _ := io.ReadAll(resp.Body)
+	resp.Body.Close()
+	elapsed := time.Since(start)
+
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("got %d, want 200 (%s)", resp.StatusCode, body)
+	}
+	if elapsed > 2*time.Second {
+		t.Fatalf("download waited %v on a wedged sink; the barrier must give up after %v", elapsed, logSyncTimeout)
+	}
+	// Giving up means serving what IS on disk, not serving nothing.
+	if !strings.Contains(string(body), "already on disk") {
+		t.Fatalf("after giving up the barrier must still stream the file:\n%s", body)
+	}
+}
+
+// No sink wired (tests, an embedder, a panel brought up on its own): the
+// download must behave exactly as it did before the barrier existed.
+func TestLogDownloadWithoutSyncSeam(t *testing.T) {
+	g := model.DefaultGlobals()
+	withLogSeams(t, g, "2026-07-23T08:00:00Z INFO line without a sink\n")
+
+	s := newTestServer(t) // SetLogSync deliberately never called
+	srv := httptest.NewServer(s.Handler())
+	defer srv.Close()
+	cookie := login(t, srv, s)
+
+	resp := getDaemonLog(t, srv, cookie, "?range=all")
+	body, _ := io.ReadAll(resp.Body)
+	resp.Body.Close()
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("got %d, want 200 (%s)", resp.StatusCode, body)
+	}
+	if !strings.Contains(string(body), "line without a sink") {
+		t.Fatalf("body missing the file content:\n%s", body)
+	}
+}

shater/panel/server.go

@@ -85,6 +85,10 @@ type Server struct {
 	opts  Options
 	log   log.ContextLogger
 
+	// logSync is the daemon's log-sink barrier (logsink.Sink.Sync), installed by
+	// SetLogSync. nil => the panel runs without a sink and reads the file as-is.
+	logSync func()
+
 	srv     *http.Server
 	handler http.Handler
 
@@ -125,6 +129,22 @@ func NewServer(a *apply.Applier, opts Options) *Server {
 // Safe to leave unset — the endpoints then report empty aggregates.
 func (s *Server) SetStats(agg stats.StatsStore) { s.stats = agg }
 
+// SetLogSync installs the operational-log barrier — in the daemon,
+// logsink.Sink.Sync — that turns "queued" into "written" for GET /api/log.
+//
+// The sink writes ASYNCHRONOUSLY (a bounded queue between the goroutines that log
+// and the one goroutine that owns stderr and the file; see shater/logsink), so
+// the newest lines can still be in flight when a download opens the file by path.
+// Those are exactly the lines an operator downloads the log FOR — they are
+// debugging what just happened — and losing them would be silent: the file is
+// served fine, just short of its tail.
+//
+// The panel is the sink's CONSUMER, not its owner: it gets a barrier function,
+// never the *Sink. Wired once at startup, like SetStats. Leaving it unset is
+// valid — /api/log then reads whatever is on disk, which is the pre-async
+// behaviour and all a panel without a sink (tests, an embedder) can promise.
+func (s *Server) SetLogSync(fn func()) { s.logSync = fn }
+
 // Handler exposes the fully-wired http.Handler (auth middleware + API + SPA) so
 // tests can drive it via httptest without opening a socket.
 func (s *Server) Handler() http.Handler { return s.handler }