Merge branch 'main' into dylan/derp-hosting-provider

.github/workflows/codeql-analysis.yml

@@ -55,7 +55,7 @@ jobs:
 
     # Initializes the CodeQL tools for scanning.
     - name: Initialize CodeQL
-      uses: github/codeql-action/init@fca7ace96b7d713c7035871441bd52efbe39e27e # v3.28.19
+      uses: github/codeql-action/init@ce28f5bb42b7a9f2c824e633a3f6ee835bab6858 # v3.29.0
       with:
         languages: ${{ matrix.language }}
         # If you wish to specify custom queries, you can do so here or in a config file.
@@ -66,7 +66,7 @@ jobs:
     # Autobuild attempts to build any compiled languages  (C/C++, C#, or Java).
     # If this step fails, then you should remove it and run the build manually (see below)
     - name: Autobuild
-      uses: github/codeql-action/autobuild@fca7ace96b7d713c7035871441bd52efbe39e27e # v3.28.19
+      uses: github/codeql-action/autobuild@ce28f5bb42b7a9f2c824e633a3f6ee835bab6858 # v3.29.0
 
     # ℹ️ Command-line programs to run using the OS shell.
     # 📚 https://git.io/JvXDl
@@ -80,4 +80,4 @@ jobs:
     #   make release
 
     - name: Perform CodeQL Analysis
-      uses: github/codeql-action/analyze@fca7ace96b7d713c7035871441bd52efbe39e27e # v3.28.19
+      uses: github/codeql-action/analyze@ce28f5bb42b7a9f2c824e633a3f6ee835bab6858 # v3.29.0

.github/workflows/test.yml

@@ -15,6 +15,10 @@ env:
   #  - false: we expect fuzzing to be happy, and should report failure if it's not.
   #  - true: we expect fuzzing is broken, and should report failure if it start working.
   TS_FUZZ_CURRENTLY_BROKEN: false
+  # GOMODCACHE is the same definition on all OSes. Within the workspace, we use
+  # toplevel directories "src" (for the checked out source code), and "gomodcache"
+  # and other caches as siblings to follow.
+  GOMODCACHE: ${{ github.workspace }}/gomodcache
 
 on:
   push:
@@ -38,8 +42,42 @@ concurrency:
   cancel-in-progress: true
 
 jobs:
+  gomod-cache:
+    runs-on: ubuntu-24.04
+    outputs:
+      cache-key: ${{ steps.hash.outputs.key }}
+    steps:
+      - name: Checkout
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        with:
+          path: src
+      - name: Compute cache key from go.{mod,sum}
+        id: hash
+        run: echo "key=gomod-cross3-${{ hashFiles('src/go.mod', 'src/go.sum') }}" >> $GITHUB_OUTPUT
+      # See if the cache entry already exists to avoid downloading it
+      # and doing the cache write again.
+      - id: check-cache
+        uses: actions/cache/restore@v4
+        with:
+          path: gomodcache # relative to workspace; see env note at top of file
+          key: ${{ steps.hash.outputs.key }}
+          lookup-only: true
+          enableCrossOsArchive: true
+      - name: Download modules
+        if: steps.check-cache.outputs.cache-hit != 'true'
+        working-directory: src
+        run: go mod download
+      - name: Cache Go modules
+        if: steps.check-cache.outputs.cache-hit != 'true'
+        uses: actions/cache@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
+        with:
+          path: gomodcache # relative to workspace; see env note at top of file
+          key: ${{ steps.hash.outputs.key }}
+          enableCrossOsArchive: true
+
   race-root-integration:
     runs-on: ubuntu-24.04
+    needs: gomod-cache
     strategy:
       fail-fast: false # don't abort the entire matrix if one element fails
       matrix:
@@ -51,9 +89,19 @@ jobs:
     steps:
     - name: checkout
       uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      with:
+        path: src
+    - name: Restore Go module cache
+      uses: actions/cache/restore@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
+      with:
+        path: gomodcache
+        key: ${{ needs.gomod-cache.outputs.cache-key }}
+        enableCrossOsArchive: true
     - name: build test wrapper
+      working-directory: src
       run: ./tool/go build -o /tmp/testwrapper ./cmd/testwrapper
     - name: integration tests as root
+      working-directory: src
       run: PATH=$PWD/tool:$PATH /tmp/testwrapper -exec "sudo -E" -race ./tstest/integration/
       env:
         TS_TEST_SHARD: ${{ matrix.shard }}
@@ -75,9 +123,18 @@ jobs:
             shard: '3/3'
           - goarch: "386" # thanks yaml
     runs-on: ubuntu-24.04
+    needs: gomod-cache
     steps:
     - name: checkout
       uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      with:
+        path: src
+    - name: Restore Go module cache
+      uses: actions/cache/restore@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
+      with:
+        path: gomodcache
+        key: ${{ needs.gomod-cache.outputs.cache-key }}
+        enableCrossOsArchive: true
     - name: Restore Cache
       uses: actions/cache@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
       with:
@@ -87,7 +144,6 @@ jobs:
         # fetched and extracted by tar
         path: |
           ~/.cache/go-build
-          ~/go/pkg/mod/cache
           ~\AppData\Local\go-build
         # The -2- here should be incremented when the scheme of data to be
         # cached changes (e.g. path above changes).
@@ -97,11 +153,13 @@ jobs:
           ${{ github.job }}-${{ runner.os }}-${{ matrix.goarch }}-${{ matrix.buildflags }}-go-2-
     - name: build all
       if: matrix.buildflags == '' # skip on race builder
+      working-directory: src
       run: ./tool/go build ${{matrix.buildflags}} ./...
       env:
         GOARCH: ${{ matrix.goarch }}
     - name: build variant CLIs
       if: matrix.buildflags == '' # skip on race builder
+      working-directory: src
       run: |
         export TS_USE_TOOLCHAIN=1
         ./build_dist.sh --extra-small ./cmd/tailscaled
@@ -116,19 +174,24 @@ jobs:
         sudo apt-get -y update
         sudo apt-get -y install qemu-user
     - name: build test wrapper
+      working-directory: src
       run: ./tool/go build -o /tmp/testwrapper ./cmd/testwrapper
     - name: test all
+      working-directory: src
       run: NOBASHDEBUG=true PATH=$PWD/tool:$PATH /tmp/testwrapper ./... ${{matrix.buildflags}}
       env:
         GOARCH: ${{ matrix.goarch }}
         TS_TEST_SHARD: ${{ matrix.shard }}
     - name: bench all
+      working-directory: src
       run: ./tool/go test ${{matrix.buildflags}} -bench=. -benchtime=1x -run=^$ $(for x in $(git grep -l "^func Benchmark" | xargs dirname | sort | uniq); do echo "./$x"; done)
       env:
         GOARCH: ${{ matrix.goarch }}
     - name: check that no tracked files changed
+      working-directory: src
       run: git diff --no-ext-diff --name-only --exit-code || (echo "Build/test modified the files above."; exit 1)
     - name: check that no new files were added
+      working-directory: src
       run: |
         # Note: The "error: pathspec..." you see below is normal!
         # In the success case in which there are no new untracked files,
@@ -140,22 +203,33 @@ jobs:
           exit 1
         fi
     - name: Tidy cache
+      working-directory: src
       shell: bash
       run: |
         find $(go env GOCACHE) -type f -mmin +90 -delete
-        find $(go env GOMODCACHE)/cache -type f -mmin +90 -delete
+
   windows:
     runs-on: windows-2022
+    needs: gomod-cache
     steps:
     - name: checkout
       uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      with:
+        path: src
 
     - name: Install Go
       uses: actions/setup-go@d35c59abb061a4a6fb18e82ac0862c26744d6ab5 # v5.5.0
       with:
-        go-version-file: go.mod
+        go-version-file: src/go.mod
         cache: false
 
+    - name: Restore Go module cache
+      uses: actions/cache/restore@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
+      with:
+        path: gomodcache
+        key: ${{ needs.gomod-cache.outputs.cache-key }}
+        enableCrossOsArchive: true
+
     - name: Restore Cache
       uses: actions/cache@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
       with:
@@ -165,7 +239,6 @@ jobs:
         # fetched and extracted by tar
         path: |
           ~/.cache/go-build
-          ~/go/pkg/mod/cache
           ~\AppData\Local\go-build
         # The -2- here should be incremented when the scheme of data to be
         # cached changes (e.g. path above changes).
@@ -174,19 +247,22 @@ jobs:
           ${{ github.job }}-${{ runner.os }}-go-2-${{ hashFiles('**/go.sum') }}
           ${{ github.job }}-${{ runner.os }}-go-2-
     - name: test
+      working-directory: src
       run: go run ./cmd/testwrapper ./...
     - name: bench all
+      working-directory: src
       # Don't use -bench=. -benchtime=1x.
       # Somewhere in the layers (powershell?)
       # the equals signs cause great confusion.
       run: go test ./... -bench . -benchtime 1x -run "^$"
     - name: Tidy cache
+      working-directory: src
       shell: bash
       run: |
         find $(go env GOCACHE) -type f -mmin +90 -delete
-        find $(go env GOMODCACHE)/cache -type f -mmin +90 -delete
 
   privileged:
+    needs: gomod-cache
     runs-on: ubuntu-24.04
     container:
       image: golang:latest
@@ -194,36 +270,47 @@ jobs:
     steps:
     - name: checkout
       uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      with:
+        path: src
+    - name: Restore Go module cache
+      uses: actions/cache/restore@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
+      with:
+        path: gomodcache
+        key: ${{ needs.gomod-cache.outputs.cache-key }}
+        enableCrossOsArchive: true
     - name: chown
+      working-directory: src
       run: chown -R $(id -u):$(id -g) $PWD
     - name: privileged tests
+      working-directory: src
       run: ./tool/go test ./util/linuxfw ./derp/xdp
 
   vm:
+    needs: gomod-cache
     runs-on: ["self-hosted", "linux", "vm"]
     # VM tests run with some privileges, don't let them run on 3p PRs.
     if: github.repository == 'tailscale/tailscale'
     steps:
     - name: checkout
       uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      with:
+        path: src
+    - name: Restore Go module cache
+      uses: actions/cache/restore@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
+      with:
+        path: gomodcache
+        key: ${{ needs.gomod-cache.outputs.cache-key }}
+        enableCrossOsArchive: true
     - name: Run VM tests
+      working-directory: src
       run: ./tool/go test ./tstest/integration/vms -v -no-s3 -run-vm-tests -run=TestRunUbuntu2004
       env:
         HOME: "/var/lib/ghrunner/home"
         TMPDIR: "/tmp"
         XDG_CACHE_HOME: "/var/lib/ghrunner/cache"
 
-  race-build:
-    runs-on: ubuntu-24.04
-    steps:
-    - name: checkout
-      uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-    - name: build all
-      run: ./tool/go install -race ./cmd/...
-    - name: build tests
-      run: ./tool/go test -race -exec=true ./...
-
   cross: # cross-compile checks, build only.
+    needs: gomod-cache
     strategy:
       fail-fast: false # don't abort the entire matrix if one element fails
       matrix:
@@ -262,6 +349,8 @@ jobs:
     steps:
     - name: checkout
       uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      with:
+        path: src
     - name: Restore Cache
       uses: actions/cache@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
       with:
@@ -271,7 +360,6 @@ jobs:
         # fetched and extracted by tar
         path: |
           ~/.cache/go-build
-          ~/go/pkg/mod/cache
           ~\AppData\Local\go-build
         # The -2- here should be incremented when the scheme of data to be
         # cached changes (e.g. path above changes).
@@ -279,7 +367,14 @@ jobs:
         restore-keys: |
           ${{ github.job }}-${{ runner.os }}-${{ matrix.goos }}-${{ matrix.goarch }}-go-2-${{ hashFiles('**/go.sum') }}
           ${{ github.job }}-${{ runner.os }}-${{ matrix.goos }}-${{ matrix.goarch }}-go-2-
+    - name: Restore Go module cache
+      uses: actions/cache/restore@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
+      with:
+        path: gomodcache
+        key: ${{ needs.gomod-cache.outputs.cache-key }}
+        enableCrossOsArchive: true
     - name: build all
+      working-directory: src
       run: ./tool/go build ./cmd/...
       env:
         GOOS: ${{ matrix.goos }}
@@ -287,30 +382,42 @@ jobs:
         GOARM: ${{ matrix.goarm }}
         CGO_ENABLED: "0"
     - name: build tests
+      working-directory: src
       run: ./tool/go test -exec=true ./...
       env:
         GOOS: ${{ matrix.goos }}
         GOARCH: ${{ matrix.goarch }}
         CGO_ENABLED: "0"
     - name: Tidy cache
+      working-directory: src
       shell: bash
       run: |
         find $(go env GOCACHE) -type f -mmin +90 -delete
-        find $(go env GOMODCACHE)/cache -type f -mmin +90 -delete
 
   ios: # similar to cross above, but iOS can't build most of the repo. So, just
-       #make it build a few smoke packages.
+       # make it build a few smoke packages.
     runs-on: ubuntu-24.04
+    needs: gomod-cache
     steps:
     - name: checkout
       uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      with:
+        path: src
+    - name: Restore Go module cache
+      uses: actions/cache/restore@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
+      with:
+        path: gomodcache
+        key: ${{ needs.gomod-cache.outputs.cache-key }}
+        enableCrossOsArchive: true
     - name: build some
+      working-directory: src
       run: ./tool/go build ./ipn/... ./ssh/tailssh ./wgengine/ ./types/... ./control/controlclient
       env:
         GOOS: ios
         GOARCH: arm64
 
   crossmin: # cross-compile for platforms where we only check cmd/tailscale{,d}
+    needs: gomod-cache
     strategy:
       fail-fast: false # don't abort the entire matrix if one element fails
       matrix:
@@ -332,6 +439,8 @@ jobs:
     steps:
     - name: checkout
       uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      with:
+        path: src
     - name: Restore Cache
       uses: actions/cache@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
       with:
@@ -341,7 +450,6 @@ jobs:
         # fetched and extracted by tar
         path: |
           ~/.cache/go-build
-          ~/go/pkg/mod/cache
           ~\AppData\Local\go-build
         # The -2- here should be incremented when the scheme of data to be
         # cached changes (e.g. path above changes).
@@ -349,7 +457,14 @@ jobs:
         restore-keys: |
           ${{ github.job }}-${{ runner.os }}-${{ matrix.goos }}-${{ matrix.goarch }}-go-2-${{ hashFiles('**/go.sum') }}
           ${{ github.job }}-${{ runner.os }}-${{ matrix.goos }}-${{ matrix.goarch }}-go-2-
+    - name: Restore Go module cache
+      uses: actions/cache/restore@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
+      with:
+        path: gomodcache
+        key: ${{ needs.gomod-cache.outputs.cache-key }}
+        enableCrossOsArchive: true
     - name: build core
+      working-directory: src
       run: ./tool/go build ./cmd/tailscale ./cmd/tailscaled
       env:
         GOOS: ${{ matrix.goos }}
@@ -357,24 +472,34 @@ jobs:
         GOARM: ${{ matrix.goarm }}
         CGO_ENABLED: "0"
     - name: Tidy cache
+      working-directory: src
       shell: bash
       run: |
         find $(go env GOCACHE) -type f -mmin +90 -delete
-        find $(go env GOMODCACHE)/cache -type f -mmin +90 -delete
 
   android:
     # similar to cross above, but android fails to build a few pieces of the
     # repo. We should fix those pieces, they're small, but as a stepping stone,
     # only test the subset of android that our past smoke test checked.
     runs-on: ubuntu-24.04
+    needs: gomod-cache
     steps:
     - name: checkout
       uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      with:
+        path: src
       # Super minimal Android build that doesn't even use CGO and doesn't build everything that's needed
       # and is only arm64. But it's a smoke build: it's not meant to catch everything. But it'll catch
       # some Android breakages early.
       # TODO(bradfitz): better; see https://github.com/tailscale/tailscale/issues/4482
+    - name: Restore Go module cache
+      uses: actions/cache/restore@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
+      with:
+        path: gomodcache
+        key: ${{ needs.gomod-cache.outputs.cache-key }}
+        enableCrossOsArchive: true
     - name: build some
+      working-directory: src
       run: ./tool/go install ./net/netns ./ipn/ipnlocal ./wgengine/magicsock/ ./wgengine/ ./wgengine/router/ ./wgengine/netstack ./util/dnsname/ ./ipn/ ./net/netmon ./wgengine/router/ ./tailcfg/ ./types/logger/ ./net/dns ./hostinfo ./version ./ssh/tailssh
       env:
         GOOS: android
@@ -382,9 +507,12 @@ jobs:
 
   wasm: # builds tsconnect, which is the only wasm build we support
     runs-on: ubuntu-24.04
+    needs: gomod-cache
     steps:
     - name: checkout
       uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      with:
+        path: src
     - name: Restore Cache
       uses: actions/cache@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
       with:
@@ -394,7 +522,6 @@ jobs:
         # fetched and extracted by tar
         path: |
           ~/.cache/go-build
-          ~/go/pkg/mod/cache
           ~\AppData\Local\go-build
         # The -2- here should be incremented when the scheme of data to be
         # cached changes (e.g. path above changes).
@@ -402,28 +529,45 @@ jobs:
         restore-keys: |
           ${{ github.job }}-${{ runner.os }}-go-2-${{ hashFiles('**/go.sum') }}
           ${{ github.job }}-${{ runner.os }}-go-2-
+    - name: Restore Go module cache
+      uses: actions/cache/restore@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
+      with:
+        path: gomodcache
+        key: ${{ needs.gomod-cache.outputs.cache-key }}
+        enableCrossOsArchive: true
     - name: build tsconnect client
+      working-directory: src
       run: ./tool/go build ./cmd/tsconnect/wasm ./cmd/tailscale/cli
       env:
         GOOS: js
         GOARCH: wasm
     - name: build tsconnect server
+      working-directory: src
       # Note, no GOOS/GOARCH in env on this build step, we're running a build
       # tool that handles the build itself.
       run: |
         ./tool/go run ./cmd/tsconnect --fast-compression build
         ./tool/go run ./cmd/tsconnect --fast-compression build-pkg
     - name: Tidy cache
+      working-directory: src
       shell: bash
       run: |
         find $(go env GOCACHE) -type f -mmin +90 -delete
-        find $(go env GOMODCACHE)/cache -type f -mmin +90 -delete
 
   tailscale_go: # Subset of tests that depend on our custom Go toolchain.
     runs-on: ubuntu-24.04
+    needs: gomod-cache
     steps:
     - name: checkout
       uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+    - name: Set GOMODCACHE env
+      run: echo "GOMODCACHE=$HOME/.cache/go-mod" >> $GITHUB_ENV
+    - name: Restore Go module cache
+      uses: actions/cache/restore@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
+      with:
+        path: gomodcache
+        key: ${{ needs.gomod-cache.outputs.cache-key }}
+        enableCrossOsArchive: true
     - name: test tailscale_go
       run: ./tool/go test -tags=tailscale_go,ts_enable_sockstats ./net/sockstats/...
 
@@ -477,7 +621,7 @@ jobs:
       uses: google/oss-fuzz/infra/cifuzz/actions/run_fuzzers@master
       with:
         oss-fuzz-project-name: 'tailscale'
-        fuzz-seconds: 300
+        fuzz-seconds: 150
         dry-run: false
         language: go
     - name: Set artifacts_path in env (workaround for actions/upload-artifact#176)
@@ -493,19 +637,40 @@ jobs:
 
   depaware:
     runs-on: ubuntu-24.04
+    needs: gomod-cache
     steps:
     - name: checkout
       uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      with:
+        path: src
+    - name: Set GOMODCACHE env
+      run: echo "GOMODCACHE=$HOME/.cache/go-mod" >> $GITHUB_ENV
+    - name: Restore Go module cache
+      uses: actions/cache/restore@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
+      with:
+        path: gomodcache
+        key: ${{ needs.gomod-cache.outputs.cache-key }}
+        enableCrossOsArchive: true
     - name: check depaware
-      run: |
+      working-directory: src
-        make depaware
+      run: make depaware
 
   go_generate:
     runs-on: ubuntu-24.04
+    needs: gomod-cache
     steps:
     - name: checkout
       uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      with:
+        path: src
+    - name: Restore Go module cache
+      uses: actions/cache/restore@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
+      with:
+        path: gomodcache
+        key: ${{ needs.gomod-cache.outputs.cache-key }}
+        enableCrossOsArchive: true
     - name: check that 'go generate' is clean
+      working-directory: src
       run: |
         pkgs=$(./tool/go list ./... | grep -Ev 'dnsfallback|k8s-operator|xdp')
         ./tool/go generate $pkgs
@@ -515,10 +680,20 @@ jobs:
 
   go_mod_tidy:
     runs-on: ubuntu-24.04
+    needs: gomod-cache
     steps:
     - name: checkout
       uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      with:
+        path: src
+    - name: Restore Go module cache
+      uses: actions/cache/restore@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
+      with:
+        path: gomodcache
+        key: ${{ needs.gomod-cache.outputs.cache-key }}
+        enableCrossOsArchive: true
     - name: check that 'go mod tidy' is clean
+      working-directory: src
       run: |
         ./tool/go mod tidy
         echo
@@ -527,14 +702,27 @@ jobs:
 
   licenses:
     runs-on: ubuntu-24.04
+    needs: gomod-cache
     steps:
     - name: checkout
       uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      with:
+        path: src
+    - name: Restore Go module cache
+      uses: actions/cache/restore@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
+      with:
+        path: gomodcache
+        key: ${{ needs.gomod-cache.outputs.cache-key }}
+        enableCrossOsArchive: true
     - name: check licenses
-      run: ./scripts/check_license_headers.sh .
+      working-directory: src
+      run: |
+        grep -q TestLicenseHeaders *.go || (echo "Expected a test named TestLicenseHeaders"; exit 1)
+        ./tool/go test -v -run=TestLicenseHeaders
 
   staticcheck:
     runs-on: ubuntu-24.04
+    needs: gomod-cache
     strategy:
       fail-fast: false # don't abort the entire matrix if one element fails
       matrix:
@@ -546,16 +734,22 @@ jobs:
     steps:
     - name: checkout
       uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-    - name: install staticcheck
+      with:
-      run: GOBIN=~/.local/bin ./tool/go install honnef.co/go/tools/cmd/staticcheck
+        path: src
+    - name: Restore Go module cache
+      uses: actions/cache/restore@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
+      with:
+        path: gomodcache
+        key: ${{ needs.gomod-cache.outputs.cache-key }}
+        enableCrossOsArchive: true
     - name: run staticcheck
+      working-directory: src
       run: |
         export GOROOT=$(./tool/go env GOROOT)
-        export PATH=$GOROOT/bin:$PATH
+        ./tool/go run -exec \
-        staticcheck -- $(./tool/go list ./... | grep -v tempfork)
+          "env GOOS=${{ matrix.goos }} GOARCH=${{ matrix.goarch }}" \
-      env:
+           honnef.co/go/tools/cmd/staticcheck -- \
-        GOOS: ${{ matrix.goos }}
+           $(env GOOS=${{ matrix.goos }} GOARCH=${{ matrix.goarch }} ./tool/go list ./... | grep -v tempfork)
-        GOARCH: ${{ matrix.goarch }}
 
   notify_slack:
     if: always()

chirp/chirp_test.go

@@ -1,5 +1,6 @@
 // Copyright (c) Tailscale Inc & AUTHORS
 // SPDX-License-Identifier: BSD-3-Clause
+
 package chirp
 
 import (

client/local/local.go

@@ -1,12 +1,11 @@
 // Copyright (c) Tailscale Inc & AUTHORS
 // SPDX-License-Identifier: BSD-3-Clause
 
-//go:build go1.22
-
 // Package local contains a Go client for the Tailscale LocalAPI.
 package local
 
 import (
+	"bufio"
 	"bytes"
 	"cmp"
 	"context"
@@ -16,6 +15,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"iter"
 	"net"
 	"net/http"
 	"net/http/httptrace"
@@ -42,6 +42,7 @@ import (
 	"tailscale.com/types/dnstype"
 	"tailscale.com/types/key"
 	"tailscale.com/types/tkatype"
+	"tailscale.com/util/eventbus"
 	"tailscale.com/util/syspolicy/setting"
 )
 
@@ -414,24 +415,42 @@ func (lc *Client) TailDaemonLogs(ctx context.Context) (io.Reader, error) {
 	return res.Body, nil
 }
 
-// StreamBusEvents returns a stream of the Tailscale bus events as they arrive.
+// StreamBusEvents returns an iterator of Tailscale bus events as they arrive.
-// Close the context to stop the stream.
+// Each pair is a valid event and a nil error, or a zero event a non-nil error.
-// Expected response from the server is newline-delimited JSON.
+// In case of error, the iterator ends after the pair reporting the error.
-// The caller must close the reader when it is finished reading.
+// Iteration stops if ctx ends.
-func (lc *Client) StreamBusEvents(ctx context.Context) (io.ReadCloser, error) {
+func (lc *Client) StreamBusEvents(ctx context.Context) iter.Seq2[eventbus.DebugEvent, error] {
-	req, err := http.NewRequestWithContext(ctx, "GET",
+	return func(yield func(eventbus.DebugEvent, error) bool) {
-		"http://"+apitype.LocalAPIHost+"/localapi/v0/debug-bus-events", nil)
+		req, err := http.NewRequestWithContext(ctx, "GET",
-	if err != nil {
+			"http://"+apitype.LocalAPIHost+"/localapi/v0/debug-bus-events", nil)
-		return nil, err
+		if err != nil {
+			yield(eventbus.DebugEvent{}, err)
+			return
+		}
+		res, err := lc.doLocalRequestNiceError(req)
+		if err != nil {
+			yield(eventbus.DebugEvent{}, err)
+			return
+		}
+		if res.StatusCode != http.StatusOK {
+			yield(eventbus.DebugEvent{}, errors.New(res.Status))
+			return
+		}
+		defer res.Body.Close()
+		dec := json.NewDecoder(bufio.NewReader(res.Body))
+		for {
+			var evt eventbus.DebugEvent
+			if err := dec.Decode(&evt); err == io.EOF {
+				return
+			} else if err != nil {
+				yield(eventbus.DebugEvent{}, err)
+				return
+			}
+			if !yield(evt, nil) {
+				return
+			}
+		}
 	}
-	res, err := lc.doLocalRequestNiceError(req)
-	if err != nil {
-		return nil, err
-	}
-	if res.StatusCode != http.StatusOK {
-		return nil, errors.New(res.Status)
-	}
-	return res.Body, nil
 }
 
 // Pprof returns a pprof profile of the Tailscale daemon.

cmd/cloner/cloner_test.go

@@ -1,5 +1,6 @@
 // Copyright (c) Tailscale Inc & AUTHORS
 // SPDX-License-Identifier: BSD-3-Clause
+
 package main
 
 import (

cmd/derper/depaware.txt

@@ -157,7 +157,7 @@ tailscale.com/cmd/derper dependencies: (generated by github.com/tailscale/depawa
      💣 tailscale.com/util/deephash                                  from tailscale.com/util/syspolicy/setting
    L 💣 tailscale.com/util/dirwalk                                   from tailscale.com/metrics
         tailscale.com/util/dnsname                                   from tailscale.com/hostinfo+
-        tailscale.com/util/eventbus                                  from tailscale.com/net/netmon
+        tailscale.com/util/eventbus                                  from tailscale.com/net/netmon+
      💣 tailscale.com/util/hashx                                     from tailscale.com/util/deephash
         tailscale.com/util/httpm                                     from tailscale.com/client/tailscale
         tailscale.com/util/lineiter                                  from tailscale.com/hostinfo+

cmd/gitops-pusher/gitops-pusher_test.go

@@ -1,5 +1,6 @@
 // Copyright (c) Tailscale Inc & AUTHORS
 // SPDX-License-Identifier: BSD-3-Clause
+
 package main
 
 import (

cmd/k8s-operator/ingress-for-pg.go

@@ -252,7 +252,7 @@ func (r *HAIngressReconciler) maybeProvision(ctx context.Context, hostname strin
 		return false, fmt.Errorf("error determining DNS name base: %w", err)
 	}
 	dnsName := hostname + "." + tcd
-	if err := r.ensureCertResources(ctx, pgName, dnsName, ing); err != nil {
+	if err := r.ensureCertResources(ctx, pg, dnsName, ing); err != nil {
 		return false, fmt.Errorf("error ensuring cert resources: %w", err)
 	}
 
@@ -931,18 +931,31 @@ func ownersAreSetAndEqual(a, b *tailscale.VIPService) bool {
 // (domain) is a valid Kubernetes resource name.
 // https://github.com/tailscale/tailscale/blob/8b1e7f646ee4730ad06c9b70c13e7861b964949b/util/dnsname/dnsname.go#L99
 // https://kubernetes.io/docs/concepts/overview/working-with-objects/names/#dns-subdomain-names
-func (r *HAIngressReconciler) ensureCertResources(ctx context.Context, pgName, domain string, ing *networkingv1.Ingress) error {
+func (r *HAIngressReconciler) ensureCertResources(ctx context.Context, pg *tsapi.ProxyGroup, domain string, ing *networkingv1.Ingress) error {
-	secret := certSecret(pgName, r.tsNamespace, domain, ing)
+	secret := certSecret(pg.Name, r.tsNamespace, domain, ing)
-	if _, err := createOrUpdate(ctx, r.Client, r.tsNamespace, secret, nil); err != nil {
+	if _, err := createOrUpdate(ctx, r.Client, r.tsNamespace, secret, func(s *corev1.Secret) {
+		// Labels might have changed if the Ingress has been updated to use a
+		// different ProxyGroup.
+		s.Labels = secret.Labels
+	}); err != nil {
 		return fmt.Errorf("failed to create or update Secret %s: %w", secret.Name, err)
 	}
-	role := certSecretRole(pgName, r.tsNamespace, domain)
+	role := certSecretRole(pg.Name, r.tsNamespace, domain)
-	if _, err := createOrUpdate(ctx, r.Client, r.tsNamespace, role, nil); err != nil {
+	if _, err := createOrUpdate(ctx, r.Client, r.tsNamespace, role, func(r *rbacv1.Role) {
+		// Labels might have changed if the Ingress has been updated to use a
+		// different ProxyGroup.
+		r.Labels = role.Labels
+	}); err != nil {
 		return fmt.Errorf("failed to create or update Role %s: %w", role.Name, err)
 	}
-	rb := certSecretRoleBinding(pgName, r.tsNamespace, domain)
+	rolebinding := certSecretRoleBinding(pg.Name, r.tsNamespace, domain)
-	if _, err := createOrUpdate(ctx, r.Client, r.tsNamespace, rb, nil); err != nil {
+	if _, err := createOrUpdate(ctx, r.Client, r.tsNamespace, rolebinding, func(rb *rbacv1.RoleBinding) {
-		return fmt.Errorf("failed to create or update RoleBinding %s: %w", rb.Name, err)
+		// Labels and subjects might have changed if the Ingress has been updated to use a
+		// different ProxyGroup.
+		rb.Labels = rolebinding.Labels
+		rb.Subjects = rolebinding.Subjects
+	}); err != nil {
+		return fmt.Errorf("failed to create or update RoleBinding %s: %w", rolebinding.Name, err)
 	}
 	return nil
 }

cmd/k8s-operator/ingress-for-pg_test.go

@@ -69,7 +69,7 @@ func TestIngressPGReconciler(t *testing.T) {
 	expectReconciled(t, ingPGR, "default", "test-ingress")
 	verifyServeConfig(t, fc, "svc:my-svc", false)
 	verifyTailscaleService(t, ft, "svc:my-svc", []string{"tcp:443"})
-	verifyTailscaledConfig(t, fc, []string{"svc:my-svc"})
+	verifyTailscaledConfig(t, fc, "test-pg", []string{"svc:my-svc"})
 
 	// Verify that Role and RoleBinding have been created for the first Ingress.
 	// Do not verify the cert Secret as that was already verified implicitly above.
@@ -132,7 +132,7 @@ func TestIngressPGReconciler(t *testing.T) {
 	verifyServeConfig(t, fc, "svc:my-other-svc", false)
 	verifyTailscaleService(t, ft, "svc:my-other-svc", []string{"tcp:443"})
 
-	// Verify that Role and RoleBinding have been created for the first Ingress.
+	// Verify that Role and RoleBinding have been created for the second Ingress.
 	// Do not verify the cert Secret as that was already verified implicitly above.
 	expectEqual(t, fc, certSecretRole("test-pg", "operator-ns", "my-other-svc.ts.net"))
 	expectEqual(t, fc, certSecretRoleBinding("test-pg", "operator-ns", "my-other-svc.ts.net"))
@@ -141,7 +141,7 @@ func TestIngressPGReconciler(t *testing.T) {
 	verifyServeConfig(t, fc, "svc:my-svc", false)
 	verifyTailscaleService(t, ft, "svc:my-svc", []string{"tcp:443"})
 
-	verifyTailscaledConfig(t, fc, []string{"svc:my-svc", "svc:my-other-svc"})
+	verifyTailscaledConfig(t, fc, "test-pg", []string{"svc:my-svc", "svc:my-other-svc"})
 
 	// Delete second Ingress
 	if err := fc.Delete(context.Background(), ing2); err != nil {
@@ -172,11 +172,20 @@ func TestIngressPGReconciler(t *testing.T) {
 		t.Error("second Ingress service config was not cleaned up")
 	}
 
-	verifyTailscaledConfig(t, fc, []string{"svc:my-svc"})
+	verifyTailscaledConfig(t, fc, "test-pg", []string{"svc:my-svc"})
 	expectMissing[corev1.Secret](t, fc, "operator-ns", "my-other-svc.ts.net")
 	expectMissing[rbacv1.Role](t, fc, "operator-ns", "my-other-svc.ts.net")
 	expectMissing[rbacv1.RoleBinding](t, fc, "operator-ns", "my-other-svc.ts.net")
 
+	// Test Ingress ProxyGroup change
+	createPGResources(t, fc, "test-pg-second")
+	mustUpdate(t, fc, "default", "test-ingress", func(ing *networkingv1.Ingress) {
+		ing.Annotations["tailscale.com/proxy-group"] = "test-pg-second"
+	})
+	expectReconciled(t, ingPGR, "default", "test-ingress")
+	expectEqual(t, fc, certSecretRole("test-pg-second", "operator-ns", "my-svc.ts.net"))
+	expectEqual(t, fc, certSecretRoleBinding("test-pg-second", "operator-ns", "my-svc.ts.net"))
+
 	// Delete the first Ingress and verify cleanup
 	if err := fc.Delete(context.Background(), ing); err != nil {
 		t.Fatalf("deleting Ingress: %v", err)
@@ -187,7 +196,7 @@ func TestIngressPGReconciler(t *testing.T) {
 	// Verify the ConfigMap was cleaned up
 	cm = &corev1.ConfigMap{}
 	if err := fc.Get(context.Background(), types.NamespacedName{
-		Name:      "test-pg-ingress-config",
+		Name:      "test-pg-second-ingress-config",
 		Namespace: "operator-ns",
 	}, cm); err != nil {
 		t.Fatalf("getting ConfigMap: %v", err)
@@ -201,7 +210,7 @@ func TestIngressPGReconciler(t *testing.T) {
 	if len(cfg.Services) > 0 {
 		t.Error("serve config not cleaned up")
 	}
-	verifyTailscaledConfig(t, fc, nil)
+	verifyTailscaledConfig(t, fc, "test-pg-second", nil)
 
 	// Add verification that cert resources were cleaned up
 	expectMissing[corev1.Secret](t, fc, "operator-ns", "my-svc.ts.net")
@@ -245,7 +254,7 @@ func TestIngressPGReconciler_UpdateIngressHostname(t *testing.T) {
 	expectReconciled(t, ingPGR, "default", "test-ingress")
 	verifyServeConfig(t, fc, "svc:my-svc", false)
 	verifyTailscaleService(t, ft, "svc:my-svc", []string{"tcp:443"})
-	verifyTailscaledConfig(t, fc, []string{"svc:my-svc"})
+	verifyTailscaledConfig(t, fc, "test-pg", []string{"svc:my-svc"})
 
 	// Update the Ingress hostname and make sure the original Tailscale Service is deleted.
 	mustUpdate(t, fc, "default", "test-ingress", func(ing *networkingv1.Ingress) {
@@ -256,7 +265,7 @@ func TestIngressPGReconciler_UpdateIngressHostname(t *testing.T) {
 	expectReconciled(t, ingPGR, "default", "test-ingress")
 	verifyServeConfig(t, fc, "svc:updated-svc", false)
 	verifyTailscaleService(t, ft, "svc:updated-svc", []string{"tcp:443"})
-	verifyTailscaledConfig(t, fc, []string{"svc:updated-svc"})
+	verifyTailscaledConfig(t, fc, "test-pg", []string{"svc:updated-svc"})
 
 	_, err := ft.GetVIPService(context.Background(), tailcfg.ServiceName("svc:my-svc"))
 	if err == nil {
@@ -550,183 +559,6 @@ func TestIngressPGReconciler_HTTPEndpoint(t *testing.T) {
 	}
 }
 
-func verifyTailscaleService(t *testing.T, ft *fakeTSClient, serviceName string, wantPorts []string) {
-	t.Helper()
-	tsSvc, err := ft.GetVIPService(context.Background(), tailcfg.ServiceName(serviceName))
-	if err != nil {
-		t.Fatalf("getting Tailscale Service %q: %v", serviceName, err)
-	}
-	if tsSvc == nil {
-		t.Fatalf("Tailscale Service %q not created", serviceName)
-	}
-	gotPorts := slices.Clone(tsSvc.Ports)
-	slices.Sort(gotPorts)
-	slices.Sort(wantPorts)
-	if !slices.Equal(gotPorts, wantPorts) {
-		t.Errorf("incorrect ports for Tailscale Service %q: got %v, want %v", serviceName, gotPorts, wantPorts)
-	}
-}
-
-func verifyServeConfig(t *testing.T, fc client.Client, serviceName string, wantHTTP bool) {
-	t.Helper()
-
-	cm := &corev1.ConfigMap{}
-	if err := fc.Get(context.Background(), types.NamespacedName{
-		Name:      "test-pg-ingress-config",
-		Namespace: "operator-ns",
-	}, cm); err != nil {
-		t.Fatalf("getting ConfigMap: %v", err)
-	}
-
-	cfg := &ipn.ServeConfig{}
-	if err := json.Unmarshal(cm.BinaryData["serve-config.json"], cfg); err != nil {
-		t.Fatalf("unmarshaling serve config: %v", err)
-	}
-
-	t.Logf("Looking for service %q in config: %+v", serviceName, cfg)
-
-	svc := cfg.Services[tailcfg.ServiceName(serviceName)]
-	if svc == nil {
-		t.Fatalf("service %q not found in serve config, services: %+v", serviceName, maps.Keys(cfg.Services))
-	}
-
-	wantHandlers := 1
-	if wantHTTP {
-		wantHandlers = 2
-	}
-
-	// Check TCP handlers
-	if len(svc.TCP) != wantHandlers {
-		t.Errorf("incorrect number of TCP handlers for service %q: got %d, want %d", serviceName, len(svc.TCP), wantHandlers)
-	}
-	if wantHTTP {
-		if h, ok := svc.TCP[uint16(80)]; !ok {
-			t.Errorf("HTTP (port 80) handler not found for service %q", serviceName)
-		} else if !h.HTTP {
-			t.Errorf("HTTP not enabled for port 80 handler for service %q", serviceName)
-		}
-	}
-	if h, ok := svc.TCP[uint16(443)]; !ok {
-		t.Errorf("HTTPS (port 443) handler not found for service %q", serviceName)
-	} else if !h.HTTPS {
-		t.Errorf("HTTPS not enabled for port 443 handler for service %q", serviceName)
-	}
-
-	// Check Web handlers
-	if len(svc.Web) != wantHandlers {
-		t.Errorf("incorrect number of Web handlers for service %q: got %d, want %d", serviceName, len(svc.Web), wantHandlers)
-	}
-}
-
-func verifyTailscaledConfig(t *testing.T, fc client.Client, expectedServices []string) {
-	t.Helper()
-	var expected string
-	if expectedServices != nil && len(expectedServices) > 0 {
-		expectedServicesJSON, err := json.Marshal(expectedServices)
-		if err != nil {
-			t.Fatalf("marshaling expected services: %v", err)
-		}
-		expected = fmt.Sprintf(`,"AdvertiseServices":%s`, expectedServicesJSON)
-	}
-	expectEqual(t, fc, &corev1.Secret{
-		ObjectMeta: metav1.ObjectMeta{
-			Name:      pgConfigSecretName("test-pg", 0),
-			Namespace: "operator-ns",
-			Labels:    pgSecretLabels("test-pg", "config"),
-		},
-		Data: map[string][]byte{
-			tsoperator.TailscaledConfigFileName(106): []byte(fmt.Sprintf(`{"Version":""%s}`, expected)),
-		},
-	})
-}
-
-func setupIngressTest(t *testing.T) (*HAIngressReconciler, client.Client, *fakeTSClient) {
-	tsIngressClass := &networkingv1.IngressClass{
-		ObjectMeta: metav1.ObjectMeta{Name: "tailscale"},
-		Spec:       networkingv1.IngressClassSpec{Controller: "tailscale.com/ts-ingress"},
-	}
-
-	// Pre-create the ProxyGroup
-	pg := &tsapi.ProxyGroup{
-		ObjectMeta: metav1.ObjectMeta{
-			Name:       "test-pg",
-			Generation: 1,
-		},
-		Spec: tsapi.ProxyGroupSpec{
-			Type: tsapi.ProxyGroupTypeIngress,
-		},
-	}
-
-	// Pre-create the ConfigMap for the ProxyGroup
-	pgConfigMap := &corev1.ConfigMap{
-		ObjectMeta: metav1.ObjectMeta{
-			Name:      "test-pg-ingress-config",
-			Namespace: "operator-ns",
-		},
-		BinaryData: map[string][]byte{
-			"serve-config.json": []byte(`{"Services":{}}`),
-		},
-	}
-
-	// Pre-create a config Secret for the ProxyGroup
-	pgCfgSecret := &corev1.Secret{
-		ObjectMeta: metav1.ObjectMeta{
-			Name:      pgConfigSecretName("test-pg", 0),
-			Namespace: "operator-ns",
-			Labels:    pgSecretLabels("test-pg", "config"),
-		},
-		Data: map[string][]byte{
-			tsoperator.TailscaledConfigFileName(106): []byte("{}"),
-		},
-	}
-
-	fc := fake.NewClientBuilder().
-		WithScheme(tsapi.GlobalScheme).
-		WithObjects(pg, pgCfgSecret, pgConfigMap, tsIngressClass).
-		WithStatusSubresource(pg).
-		Build()
-
-	// Set ProxyGroup status to ready
-	pg.Status.Conditions = []metav1.Condition{
-		{
-			Type:               string(tsapi.ProxyGroupReady),
-			Status:             metav1.ConditionTrue,
-			ObservedGeneration: 1,
-		},
-	}
-	if err := fc.Status().Update(context.Background(), pg); err != nil {
-		t.Fatal(err)
-	}
-	fakeTsnetServer := &fakeTSNetServer{certDomains: []string{"foo.com"}}
-
-	ft := &fakeTSClient{}
-	zl, err := zap.NewDevelopment()
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	lc := &fakeLocalClient{
-		status: &ipnstate.Status{
-			CurrentTailnet: &ipnstate.TailnetStatus{
-				MagicDNSSuffix: "ts.net",
-			},
-		},
-	}
-
-	ingPGR := &HAIngressReconciler{
-		Client:      fc,
-		tsClient:    ft,
-		defaultTags: []string{"tag:k8s"},
-		tsNamespace: "operator-ns",
-		tsnetServer: fakeTsnetServer,
-		logger:      zl.Sugar(),
-		recorder:    record.NewFakeRecorder(10),
-		lc:          lc,
-	}
-
-	return ingPGR, fc, ft
-}
-
 func TestIngressPGReconciler_MultiCluster(t *testing.T) {
 	ingPGR, fc, ft := setupIngressTest(t)
 	ingPGR.operatorID = "operator-1"
@@ -837,3 +669,187 @@ func populateTLSSecret(ctx context.Context, c client.Client, pgName, domain stri
 	})
 	return err
 }
+
+func verifyTailscaleService(t *testing.T, ft *fakeTSClient, serviceName string, wantPorts []string) {
+	t.Helper()
+	tsSvc, err := ft.GetVIPService(context.Background(), tailcfg.ServiceName(serviceName))
+	if err != nil {
+		t.Fatalf("getting Tailscale Service %q: %v", serviceName, err)
+	}
+	if tsSvc == nil {
+		t.Fatalf("Tailscale Service %q not created", serviceName)
+	}
+	gotPorts := slices.Clone(tsSvc.Ports)
+	slices.Sort(gotPorts)
+	slices.Sort(wantPorts)
+	if !slices.Equal(gotPorts, wantPorts) {
+		t.Errorf("incorrect ports for Tailscale Service %q: got %v, want %v", serviceName, gotPorts, wantPorts)
+	}
+}
+
+func verifyServeConfig(t *testing.T, fc client.Client, serviceName string, wantHTTP bool) {
+	t.Helper()
+
+	cm := &corev1.ConfigMap{}
+	if err := fc.Get(context.Background(), types.NamespacedName{
+		Name:      "test-pg-ingress-config",
+		Namespace: "operator-ns",
+	}, cm); err != nil {
+		t.Fatalf("getting ConfigMap: %v", err)
+	}
+
+	cfg := &ipn.ServeConfig{}
+	if err := json.Unmarshal(cm.BinaryData["serve-config.json"], cfg); err != nil {
+		t.Fatalf("unmarshaling serve config: %v", err)
+	}
+
+	t.Logf("Looking for service %q in config: %+v", serviceName, cfg)
+
+	svc := cfg.Services[tailcfg.ServiceName(serviceName)]
+	if svc == nil {
+		t.Fatalf("service %q not found in serve config, services: %+v", serviceName, maps.Keys(cfg.Services))
+	}
+
+	wantHandlers := 1
+	if wantHTTP {
+		wantHandlers = 2
+	}
+
+	// Check TCP handlers
+	if len(svc.TCP) != wantHandlers {
+		t.Errorf("incorrect number of TCP handlers for service %q: got %d, want %d", serviceName, len(svc.TCP), wantHandlers)
+	}
+	if wantHTTP {
+		if h, ok := svc.TCP[uint16(80)]; !ok {
+			t.Errorf("HTTP (port 80) handler not found for service %q", serviceName)
+		} else if !h.HTTP {
+			t.Errorf("HTTP not enabled for port 80 handler for service %q", serviceName)
+		}
+	}
+	if h, ok := svc.TCP[uint16(443)]; !ok {
+		t.Errorf("HTTPS (port 443) handler not found for service %q", serviceName)
+	} else if !h.HTTPS {
+		t.Errorf("HTTPS not enabled for port 443 handler for service %q", serviceName)
+	}
+
+	// Check Web handlers
+	if len(svc.Web) != wantHandlers {
+		t.Errorf("incorrect number of Web handlers for service %q: got %d, want %d", serviceName, len(svc.Web), wantHandlers)
+	}
+}
+
+func verifyTailscaledConfig(t *testing.T, fc client.Client, pgName string, expectedServices []string) {
+	t.Helper()
+	var expected string
+	if expectedServices != nil && len(expectedServices) > 0 {
+		expectedServicesJSON, err := json.Marshal(expectedServices)
+		if err != nil {
+			t.Fatalf("marshaling expected services: %v", err)
+		}
+		expected = fmt.Sprintf(`,"AdvertiseServices":%s`, expectedServicesJSON)
+	}
+	expectEqual(t, fc, &corev1.Secret{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      pgConfigSecretName(pgName, 0),
+			Namespace: "operator-ns",
+			Labels:    pgSecretLabels(pgName, "config"),
+		},
+		Data: map[string][]byte{
+			tsoperator.TailscaledConfigFileName(106): []byte(fmt.Sprintf(`{"Version":""%s}`, expected)),
+		},
+	})
+}
+
+func createPGResources(t *testing.T, fc client.Client, pgName string) {
+	t.Helper()
+	// Pre-create the ProxyGroup
+	pg := &tsapi.ProxyGroup{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:       pgName,
+			Generation: 1,
+		},
+		Spec: tsapi.ProxyGroupSpec{
+			Type: tsapi.ProxyGroupTypeIngress,
+		},
+	}
+	mustCreate(t, fc, pg)
+
+	// Pre-create the ConfigMap for the ProxyGroup
+	pgConfigMap := &corev1.ConfigMap{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      fmt.Sprintf("%s-ingress-config", pgName),
+			Namespace: "operator-ns",
+		},
+		BinaryData: map[string][]byte{
+			"serve-config.json": []byte(`{"Services":{}}`),
+		},
+	}
+	mustCreate(t, fc, pgConfigMap)
+
+	// Pre-create a config Secret for the ProxyGroup
+	pgCfgSecret := &corev1.Secret{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      pgConfigSecretName(pgName, 0),
+			Namespace: "operator-ns",
+			Labels:    pgSecretLabels(pgName, "config"),
+		},
+		Data: map[string][]byte{
+			tsoperator.TailscaledConfigFileName(106): []byte("{}"),
+		},
+	}
+	mustCreate(t, fc, pgCfgSecret)
+	pg.Status.Conditions = []metav1.Condition{
+		{
+			Type:               string(tsapi.ProxyGroupReady),
+			Status:             metav1.ConditionTrue,
+			ObservedGeneration: 1,
+		},
+	}
+	if err := fc.Status().Update(context.Background(), pg); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func setupIngressTest(t *testing.T) (*HAIngressReconciler, client.Client, *fakeTSClient) {
+	tsIngressClass := &networkingv1.IngressClass{
+		ObjectMeta: metav1.ObjectMeta{Name: "tailscale"},
+		Spec:       networkingv1.IngressClassSpec{Controller: "tailscale.com/ts-ingress"},
+	}
+
+	fc := fake.NewClientBuilder().
+		WithScheme(tsapi.GlobalScheme).
+		WithObjects(tsIngressClass).
+		WithStatusSubresource(&tsapi.ProxyGroup{}).
+		Build()
+
+	createPGResources(t, fc, "test-pg")
+
+	fakeTsnetServer := &fakeTSNetServer{certDomains: []string{"foo.com"}}
+
+	ft := &fakeTSClient{}
+	zl, err := zap.NewDevelopment()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	lc := &fakeLocalClient{
+		status: &ipnstate.Status{
+			CurrentTailnet: &ipnstate.TailnetStatus{
+				MagicDNSSuffix: "ts.net",
+			},
+		},
+	}
+
+	ingPGR := &HAIngressReconciler{
+		Client:      fc,
+		tsClient:    ft,
+		defaultTags: []string{"tag:k8s"},
+		tsNamespace: "operator-ns",
+		tsnetServer: fakeTsnetServer,
+		logger:      zl.Sugar(),
+		recorder:    record.NewFakeRecorder(10),
+		lc:          lc,
+	}
+
+	return ingPGR, fc, ft
+}

cmd/k8s-operator/svc-for-pg_test.go

@@ -46,7 +46,7 @@ func TestServicePGReconciler(t *testing.T) {
 
 		config = append(config, fmt.Sprintf("svc:default-%s", svc.Name))
 		verifyTailscaleService(t, ft, fmt.Sprintf("svc:default-%s", svc.Name), []string{"do-not-validate"})
-		verifyTailscaledConfig(t, fc, config)
+		verifyTailscaledConfig(t, fc, "test-pg", config)
 	}
 
 	for i, svc := range svcs {
@@ -75,7 +75,7 @@ func TestServicePGReconciler(t *testing.T) {
 		}
 
 		config = removeEl(config, fmt.Sprintf("svc:default-%s", svc.Name))
-		verifyTailscaledConfig(t, fc, config)
+		verifyTailscaledConfig(t, fc, "test-pg", config)
 	}
 }
 
@@ -88,7 +88,7 @@ func TestServicePGReconciler_UpdateHostname(t *testing.T) {
 	expectReconciled(t, svcPGR, "default", svc.Name)
 
 	verifyTailscaleService(t, ft, fmt.Sprintf("svc:default-%s", svc.Name), []string{"do-not-validate"})
-	verifyTailscaledConfig(t, fc, []string{fmt.Sprintf("svc:default-%s", svc.Name)})
+	verifyTailscaledConfig(t, fc, "test-pg", []string{fmt.Sprintf("svc:default-%s", svc.Name)})
 
 	hostname := "foobarbaz"
 	mustUpdate(t, fc, svc.Namespace, svc.Name, func(s *corev1.Service) {
@@ -100,7 +100,7 @@ func TestServicePGReconciler_UpdateHostname(t *testing.T) {
 	expectReconciled(t, svcPGR, "default", svc.Name)
 
 	verifyTailscaleService(t, ft, fmt.Sprintf("svc:%s", hostname), []string{"do-not-validate"})
-	verifyTailscaledConfig(t, fc, []string{fmt.Sprintf("svc:%s", hostname)})
+	verifyTailscaledConfig(t, fc, "test-pg", []string{fmt.Sprintf("svc:%s", hostname)})
 
 	_, err := ft.GetVIPService(context.Background(), tailcfg.ServiceName(fmt.Sprintf("svc:default-%s", svc.Name)))
 	if err == nil {
@@ -334,7 +334,7 @@ func TestIgnoreRegularService(t *testing.T) {
 	mustCreate(t, fc, svc)
 	expectReconciled(t, pgr, "default", "test")
 
-	verifyTailscaledConfig(t, fc, nil)
+	verifyTailscaledConfig(t, fc, "test-pg", nil)
 
 	tsSvcs, err := ft.ListVIPServices(context.Background())
 	if err == nil {

cmd/natc/natc.go

@@ -54,6 +54,7 @@ func main() {
 		hostname        = fs.String("hostname", "", "Hostname to register the service under")
 		siteID          = fs.Uint("site-id", 1, "an integer site ID to use for the ULA prefix which allows for multiple proxies to act in a HA configuration")
 		v4PfxStr        = fs.String("v4-pfx", "100.64.1.0/24", "comma-separated list of IPv4 prefixes to advertise")
+		dnsServers      = fs.String("dns-servers", "", "comma separated list of upstream DNS to use, including host and port (use system if empty)")
 		verboseTSNet    = fs.Bool("verbose-tsnet", false, "enable verbose logging in tsnet")
 		printULA        = fs.Bool("print-ula", false, "print the ULA prefix and exit")
 		ignoreDstPfxStr = fs.String("ignore-destinations", "", "comma-separated list of prefixes to ignore")
@@ -78,7 +79,7 @@ func main() {
 	}
 
 	var ignoreDstTable *bart.Table[bool]
-	for _, s := range strings.Split(*ignoreDstPfxStr, ",") {
+	for s := range strings.SplitSeq(*ignoreDstPfxStr, ",") {
 		s := strings.TrimSpace(s)
 		if s == "" {
 			continue
@@ -185,11 +186,37 @@ func main() {
 		ipPool:     ipp,
 		routes:     routes,
 		dnsAddr:    dnsAddr,
-		resolver:   net.DefaultResolver,
+		resolver:   getResolver(*dnsServers),
 	}
 	c.run(ctx, lc)
 }
 
+// getResolver parses serverFlag and returns either the default resolver, or a
+// resolver that uses the provided comma-separated DNS server AddrPort's, or
+// panics.
+func getResolver(serverFlag string) lookupNetIPer {
+	if serverFlag == "" {
+		return net.DefaultResolver
+	}
+	var addrs []string
+	for s := range strings.SplitSeq(serverFlag, ",") {
+		s = strings.TrimSpace(s)
+		addr, err := netip.ParseAddrPort(s)
+		if err != nil {
+			log.Fatalf("dns server provided: %q does not parse: %v", s, err)
+		}
+		addrs = append(addrs, addr.String())
+	}
+	return &net.Resolver{
+		PreferGo: true,
+		Dial: func(ctx context.Context, network string, address string) (net.Conn, error) {
+			var dialer net.Dialer
+			// TODO(raggi): perhaps something other than random?
+			return dialer.DialContext(ctx, network, addrs[rand.N(len(addrs))])
+		},
+	}
+}
+
 func calculateAddresses(prefixes []netip.Prefix) (*netipx.IPSet, netip.Addr, *netipx.IPSet) {
 	var ipsb netipx.IPSetBuilder
 	for _, p := range prefixes {

cmd/natc/natc_test.go

@@ -9,6 +9,7 @@ import (
 	"io"
 	"net"
 	"net/netip"
+	"sync"
 	"testing"
 	"time"
 
@@ -480,3 +481,198 @@ func TestV6V4(t *testing.T) {
 		}
 	}
 }
+
+// echoServer is a simple server that just echos back data set to it.
+type echoServer struct {
+	listener net.Listener
+	addr     string
+	wg       sync.WaitGroup
+	done     chan struct{}
+}
+
+// newEchoServer creates a new test DNS server on the specified network and address
+func newEchoServer(t *testing.T, network, addr string) *echoServer {
+	listener, err := net.Listen(network, addr)
+	if err != nil {
+		t.Fatalf("Failed to create test DNS server: %v", err)
+	}
+
+	server := &echoServer{
+		listener: listener,
+		addr:     listener.Addr().String(),
+		done:     make(chan struct{}),
+	}
+
+	server.wg.Add(1)
+	go server.serve()
+
+	return server
+}
+
+func (s *echoServer) serve() {
+	defer s.wg.Done()
+
+	for {
+		select {
+		case <-s.done:
+			return
+		default:
+			conn, err := s.listener.Accept()
+			if err != nil {
+				select {
+				case <-s.done:
+					return
+				default:
+					continue
+				}
+			}
+			go s.handleConnection(conn)
+		}
+	}
+}
+
+func (s *echoServer) handleConnection(conn net.Conn) {
+	defer conn.Close()
+	// Simple response - just echo back some data to confirm connectivity
+	buf := make([]byte, 1024)
+	n, err := conn.Read(buf)
+	if err != nil {
+		return
+	}
+	conn.Write(buf[:n])
+}
+
+func (s *echoServer) close() {
+	close(s.done)
+	s.listener.Close()
+	s.wg.Wait()
+}
+
+func TestGetResolver(t *testing.T) {
+	tests := []struct {
+		name    string
+		network string
+		addr    string
+	}{
+		{
+			name:    "ipv4_loopback",
+			network: "tcp4",
+			addr:    "127.0.0.1:0",
+		},
+		{
+			name:    "ipv6_loopback",
+			network: "tcp6",
+			addr:    "[::1]:0",
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			server := newEchoServer(t, tc.network, tc.addr)
+			defer server.close()
+			serverAddr := server.addr
+			resolver := getResolver(serverAddr)
+			if resolver == nil {
+				t.Fatal("getResolver returned nil")
+			}
+
+			netResolver, ok := resolver.(*net.Resolver)
+			if !ok {
+				t.Fatal("getResolver did not return a *net.Resolver")
+			}
+			if netResolver.Dial == nil {
+				t.Fatal("resolver.Dial is nil")
+			}
+
+			ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+			defer cancel()
+			conn, err := netResolver.Dial(ctx, "tcp", "dummy.address:53")
+			if err != nil {
+				t.Fatalf("Failed to dial test DNS server: %v", err)
+			}
+			defer conn.Close()
+
+			testData := []byte("test")
+			_, err = conn.Write(testData)
+			if err != nil {
+				t.Fatalf("Failed to write to connection: %v", err)
+			}
+
+			response := make([]byte, len(testData))
+			_, err = conn.Read(response)
+			if err != nil {
+				t.Fatalf("Failed to read from connection: %v", err)
+			}
+
+			if string(response) != string(testData) {
+				t.Fatalf("Expected echo response %q, got %q", testData, response)
+			}
+		})
+	}
+}
+
+func TestGetResolverMultipleServers(t *testing.T) {
+	server1 := newEchoServer(t, "tcp4", "127.0.0.1:0")
+	defer server1.close()
+	server2 := newEchoServer(t, "tcp4", "127.0.0.1:0")
+	defer server2.close()
+	serverFlag := server1.addr + ", " + server2.addr
+
+	resolver := getResolver(serverFlag)
+	netResolver, ok := resolver.(*net.Resolver)
+	if !ok {
+		t.Fatal("getResolver did not return a *net.Resolver")
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	servers := map[string]bool{
+		server1.addr: false,
+		server2.addr: false,
+	}
+
+	// Try up to 1000 times to hit all servers, this should be very quick, and
+	// if this fails randomness has regressed beyond reason.
+	for range 1000 {
+		conn, err := netResolver.Dial(ctx, "tcp", "dummy.address:53")
+		if err != nil {
+			t.Fatalf("Failed to dial test DNS server: %v", err)
+		}
+
+		remoteAddr := conn.RemoteAddr().String()
+
+		conn.Close()
+
+		servers[remoteAddr] = true
+
+		var allDone = true
+		for _, done := range servers {
+			if !done {
+				allDone = false
+				break
+			}
+		}
+		if allDone {
+			break
+		}
+	}
+
+	var allDone = true
+	for _, done := range servers {
+		if !done {
+			allDone = false
+			break
+		}
+	}
+	if !allDone {
+		t.Errorf("after 1000 queries, not all servers were hit, significant lack of randomness: %#v", servers)
+	}
+}
+
+func TestGetResolverEmpty(t *testing.T) {
+	resolver := getResolver("")
+	if resolver != net.DefaultResolver {
+		t.Fatal(`getResolver("") should return net.DefaultResolver`)
+	}
+}

cmd/proxy-to-grafana/proxy-to-grafana_test.go

@@ -1,5 +1,6 @@
 // Copyright (c) Tailscale Inc & AUTHORS
 // SPDX-License-Identifier: BSD-3-Clause
+
 package main
 
 import (

cmd/tailscale/cli/debug.go

@@ -791,21 +791,14 @@ func runDaemonLogs(ctx context.Context, args []string) error {
 }
 
 func runDaemonBusEvents(ctx context.Context, args []string) error {
-	logs, err := localClient.StreamBusEvents(ctx)
+	for line, err := range localClient.StreamBusEvents(ctx) {
-	if err != nil {
-		return err
-	}
-	defer logs.Close()
-	d := json.NewDecoder(bufio.NewReader(logs))
-	for {
-		var line eventbus.DebugEvent
-		err := d.Decode(&line)
 		if err != nil {
 			return err
 		}
 		fmt.Printf("[%d][%q][from: %q][to: %q] %s\n", line.Count, line.Type,
 			line.From, line.To, line.Event)
 	}
+	return nil
 }
 
 var metricsArgs struct {

cmd/tailscale/cli/network-lock.go

@@ -326,6 +326,9 @@ func runNetworkLockRemove(ctx context.Context, args []string) error {
 	if !st.Enabled {
 		return errors.New("tailnet lock is not enabled")
 	}
+	if len(st.TrustedKeys) == 1 {
+		return errors.New("cannot remove the last trusted signing key; use 'tailscale lock disable' to disable tailnet lock instead, or add another signing key before removing one")
+	}
 
 	if nlRemoveArgs.resign {
 		// Validate we are not removing trust in ourselves while resigning. This is because

cmd/tsidp/tsidp_test.go

@@ -1,5 +1,6 @@
 // Copyright (c) Tailscale Inc & AUTHORS
 // SPDX-License-Identifier: BSD-3-Clause
+
 package main
 
 import (

go.mod

@@ -1,6 +1,6 @@
 module tailscale.com
 
-go 1.24.0
+go 1.24.4
 
 require (
 	filippo.io/mkcert v1.4.4

ipn/ipnlocal/local.go

@@ -98,6 +98,7 @@ import (
 	"tailscale.com/util/clientmetric"
 	"tailscale.com/util/deephash"
 	"tailscale.com/util/dnsname"
+	"tailscale.com/util/eventbus"
 	"tailscale.com/util/goroutines"
 	"tailscale.com/util/httpm"
 	"tailscale.com/util/mak"
@@ -168,6 +169,17 @@ type watchSession struct {
 
 var metricCaptivePortalDetected = clientmetric.NewCounter("captiveportal_detected")
 
+var (
+	// errShutdown indicates that the [LocalBackend.Shutdown] was called.
+	errShutdown = errors.New("shutting down")
+
+	// errNodeContextChanged indicates that [LocalBackend] has switched
+	// to a different [localNodeContext], usually due to a profile change.
+	// It is used as a context cancellation cause for the old context
+	// and can be returned when an operation is performed on it.
+	errNodeContextChanged = errors.New("profile changed")
+)
+
 // LocalBackend is the glue between the major pieces of the Tailscale
 // network software: the cloud control plane (via controlclient), the
 // network data plane (via wgengine), and the user-facing UIs and CLIs
@@ -180,11 +192,11 @@ var metricCaptivePortalDetected = clientmetric.NewCounter("captiveportal_detecte
 // state machine generates events back out to zero or more components.
 type LocalBackend struct {
 	// Elements that are thread-safe or constant after construction.
-	ctx                      context.Context    // canceled by [LocalBackend.Shutdown]
+	ctx                      context.Context         // canceled by [LocalBackend.Shutdown]
-	ctxCancel                context.CancelFunc // cancels ctx
+	ctxCancel                context.CancelCauseFunc // cancels ctx
-	logf                     logger.Logf        // general logging
+	logf                     logger.Logf             // general logging
-	keyLogf                  logger.Logf        // for printing list of peers on change
+	keyLogf                  logger.Logf             // for printing list of peers on change
-	statsLogf                logger.Logf        // for printing peers stats on change
+	statsLogf                logger.Logf             // for printing peers stats on change
 	sys                      *tsd.System
 	health                   *health.Tracker // always non-nil
 	metrics                  metrics
@@ -463,7 +475,7 @@ func NewLocalBackend(logf logger.Logf, logID logid.PublicID, sys *tsd.System, lo
 
 	envknob.LogCurrent(logf)
 
-	ctx, cancel := context.WithCancel(context.Background())
+	ctx, cancel := context.WithCancelCause(context.Background())
 	clock := tstime.StdClock{}
 
 	// Until we transition to a Running state, use a canceled context for
@@ -503,7 +515,10 @@ func NewLocalBackend(logf logger.Logf, logID logid.PublicID, sys *tsd.System, lo
 		captiveCancel:         nil, // so that we start checkCaptivePortalLoop when Running
 		needsCaptiveDetection: make(chan bool),
 	}
-	b.currentNodeAtomic.Store(newNodeBackend())
+	nb := newNodeBackend(ctx, b.sys.Bus.Get())
+	b.currentNodeAtomic.Store(nb)
+	nb.ready()
+
 	mConn.SetNetInfoCallback(b.setNetInfo)
 
 	if sys.InitialConfig != nil {
@@ -585,9 +600,18 @@ func (b *LocalBackend) currentNode() *nodeBackend {
 	if v := b.currentNodeAtomic.Load(); v != nil || !testenv.InTest() {
 		return v
 	}
-	// Auto-init one in tests for LocalBackend created without the NewLocalBackend constructor...
+	// Auto-init [nodeBackend] in tests for LocalBackend created without the
-	v := newNodeBackend()
+	// NewLocalBackend() constructor. Same reasoning for checking b.sys.
-	b.currentNodeAtomic.CompareAndSwap(nil, v)
+	var bus *eventbus.Bus
+	if b.sys == nil {
+		bus = eventbus.New()
+	} else {
+		bus = b.sys.Bus.Get()
+	}
+	v := newNodeBackend(cmp.Or(b.ctx, context.Background()), bus)
+	if b.currentNodeAtomic.CompareAndSwap(nil, v) {
+		v.ready()
+	}
 	return b.currentNodeAtomic.Load()
 }
 
@@ -1089,8 +1113,9 @@ func (b *LocalBackend) Shutdown() {
 	if cc != nil {
 		cc.Shutdown()
 	}
+	b.ctxCancel(errShutdown)
+	b.currentNode().shutdown(errShutdown)
 	extHost.Shutdown()
-	b.ctxCancel()
 	b.e.Close()
 	<-b.e.Done()
 	b.awaitNoGoroutinesInTest()
@@ -6992,7 +7017,11 @@ func (b *LocalBackend) resetForProfileChangeLockedOnEntry(unlock unlockOnce) err
 		// down, so no need to do any work.
 		return nil
 	}
-	b.currentNodeAtomic.Store(newNodeBackend())
+	newNode := newNodeBackend(b.ctx, b.sys.Bus.Get())
+	if oldNode := b.currentNodeAtomic.Swap(newNode); oldNode != nil {
+		oldNode.shutdown(errNodeContextChanged)
+	}
+	defer newNode.ready()
 	b.setNetMapLocked(nil) // Reset netmap.
 	b.updateFilterLocked(ipn.PrefsView{})
 	// Reset the NetworkMap in the engine

ipn/ipnlocal/node_backend.go

@@ -5,6 +5,7 @@ package ipnlocal
 
 import (
 	"cmp"
+	"context"
 	"net/netip"
 	"slices"
 	"sync"
@@ -22,9 +23,11 @@ import (
 	"tailscale.com/types/ptr"
 	"tailscale.com/types/views"
 	"tailscale.com/util/dnsname"
+	"tailscale.com/util/eventbus"
 	"tailscale.com/util/mak"
 	"tailscale.com/util/slicesx"
 	"tailscale.com/wgengine/filter"
+	"tailscale.com/wgengine/magicsock"
 )
 
 // nodeBackend is node-specific [LocalBackend] state. It is usually the current node.
@@ -39,7 +42,7 @@ import (
 // Two pointers to different [nodeBackend] instances represent different local nodes.
 // However, there's currently a bug where a new [nodeBackend] might not be created
 // during an implicit node switch (see tailscale/corp#28014).
-
+//
 // In the future, we might want to include at least the following in this struct (in addition to the current fields).
 // However, not everything should be exported or otherwise made available to the outside world (e.g. [ipnext] extensions,
 // peer API handlers, etc.).
@@ -61,13 +64,24 @@ import (
 // Even if they're tied to the local node, instead of moving them here, we should extract the entire feature
 // into a separate package and have it install proper hooks.
 type nodeBackend struct {
+	ctx       context.Context         // canceled by [nodeBackend.shutdown]
+	ctxCancel context.CancelCauseFunc // cancels ctx
+
 	// filterAtomic is a stateful packet filter. Immutable once created, but can be
 	// replaced with a new one.
 	filterAtomic atomic.Pointer[filter.Filter]
 
+	// initialized once and immutable
+	eventClient   *eventbus.Client
+	filterUpdates *eventbus.Publisher[magicsock.FilterUpdate]
+	nodeUpdates   *eventbus.Publisher[magicsock.NodeAddrsHostInfoUpdate]
+
 	// TODO(nickkhyl): maybe use sync.RWMutex?
 	mu sync.Mutex // protects the following fields
 
+	shutdownOnce sync.Once     // guards calling [nodeBackend.shutdown]
+	readyCh      chan struct{} // closed by [nodeBackend.ready]; nil after shutdown
+
 	// NetMap is the most recently set full netmap from the controlclient.
 	// It can't be mutated in place once set. Because it can't be mutated in place,
 	// delta updates from the control server don't apply to it. Instead, use
@@ -88,12 +102,28 @@ type nodeBackend struct {
 	nodeByAddr map[netip.Addr]tailcfg.NodeID
 }
 
-func newNodeBackend() *nodeBackend {
+func newNodeBackend(ctx context.Context, bus *eventbus.Bus) *nodeBackend {
-	cn := &nodeBackend{}
+	ctx, ctxCancel := context.WithCancelCause(ctx)
+	nb := &nodeBackend{
+		ctx:         ctx,
+		ctxCancel:   ctxCancel,
+		eventClient: bus.Client("ipnlocal.nodeBackend"),
+		readyCh:     make(chan struct{}),
+	}
 	// Default filter blocks everything and logs nothing.
 	noneFilter := filter.NewAllowNone(logger.Discard, &netipx.IPSet{})
-	cn.filterAtomic.Store(noneFilter)
+	nb.filterAtomic.Store(noneFilter)
-	return cn
+	nb.filterUpdates = eventbus.Publish[magicsock.FilterUpdate](nb.eventClient)
+	nb.nodeUpdates = eventbus.Publish[magicsock.NodeAddrsHostInfoUpdate](nb.eventClient)
+	nb.filterUpdates.Publish(magicsock.FilterUpdate{Filter: nb.filterAtomic.Load()})
+	return nb
+}
+
+// Context returns a context that is canceled when the [nodeBackend] shuts down,
+// either because [LocalBackend] is switching to a different [nodeBackend]
+// or is shutting down itself.
+func (nb *nodeBackend) Context() context.Context {
+	return nb.ctx
 }
 
 func (nb *nodeBackend) Self() tailcfg.NodeView {
@@ -399,9 +429,16 @@ func (nb *nodeBackend) updatePeersLocked() {
 		nb.peers[k] = tailcfg.NodeView{}
 	}
 
+	changed := magicsock.NodeAddrsHostInfoUpdate{
+		Complete: true,
+	}
 	// Second pass, add everything wanted.
 	for _, p := range nm.Peers {
 		mak.Set(&nb.peers, p.ID(), p)
+		mak.Set(&changed.NodesByID, p.ID(), magicsock.NodeAddrsHostInfo{
+			Addresses: p.Addresses(),
+			Hostinfo:  p.Hostinfo(),
+		})
 	}
 
 	// Third pass, remove deleted things.
@@ -410,6 +447,7 @@ func (nb *nodeBackend) updatePeersLocked() {
 			delete(nb.peers, k)
 		}
 	}
+	nb.nodeUpdates.Publish(changed)
 }
 
 func (nb *nodeBackend) UpdateNetmapDelta(muts []netmap.NodeMutation) (handled bool) {
@@ -424,6 +462,9 @@ func (nb *nodeBackend) UpdateNetmapDelta(muts []netmap.NodeMutation) (handled bo
 	// call (e.g. its endpoints + online status both change)
 	var mutableNodes map[tailcfg.NodeID]*tailcfg.Node
 
+	changed := magicsock.NodeAddrsHostInfoUpdate{
+		Complete: false,
+	}
 	for _, m := range muts {
 		n, ok := mutableNodes[m.NodeIDBeingMutated()]
 		if !ok {
@@ -438,8 +479,14 @@ func (nb *nodeBackend) UpdateNetmapDelta(muts []netmap.NodeMutation) (handled bo
 		m.Apply(n)
 	}
 	for nid, n := range mutableNodes {
-		nb.peers[nid] = n.View()
+		nv := n.View()
+		nb.peers[nid] = nv
+		mak.Set(&changed.NodesByID, nid, magicsock.NodeAddrsHostInfo{
+			Addresses: nv.Addresses(),
+			Hostinfo:  nv.Hostinfo(),
+		})
 	}
+	nb.nodeUpdates.Publish(changed)
 	return true
 }
 
@@ -461,6 +508,7 @@ func (nb *nodeBackend) filter() *filter.Filter {
 
 func (nb *nodeBackend) setFilter(f *filter.Filter) {
 	nb.filterAtomic.Store(f)
+	nb.filterUpdates.Publish(magicsock.FilterUpdate{Filter: f})
 }
 
 func (nb *nodeBackend) dnsConfigForNetmap(prefs ipn.PrefsView, selfExpired bool, logf logger.Logf, versionOS string) *dns.Config {
@@ -475,6 +523,60 @@ func (nb *nodeBackend) exitNodeCanProxyDNS(exitNodeID tailcfg.StableNodeID) (doh
 	return exitNodeCanProxyDNS(nb.netMap, nb.peers, exitNodeID)
 }
 
+// ready signals that [LocalBackend] has completed the switch to this [nodeBackend]
+// and any pending calls to [nodeBackend.Wait] must be unblocked.
+func (nb *nodeBackend) ready() {
+	nb.mu.Lock()
+	defer nb.mu.Unlock()
+	if nb.readyCh != nil {
+		close(nb.readyCh)
+	}
+}
+
+// Wait blocks until [LocalBackend] completes the switch to this [nodeBackend]
+// and calls [nodeBackend.ready]. It returns an error if the provided context
+// is canceled or if the [nodeBackend] shuts down or is already shut down.
+//
+// It must not be called with the [LocalBackend]'s internal mutex held as [LocalBackend]
+// may need to acquire it to complete the switch.
+//
+// TODO(nickkhyl): Relax this restriction once [LocalBackend]'s state machine
+// runs in its own goroutine, or if we decide that waiting for the state machine
+// restart to finish isn't necessary for [LocalBackend] to consider the switch complete.
+// We mostly need this because of [LocalBackend.Start] acquiring b.mu and the fact that
+// methods like [LocalBackend.SwitchProfile] must report any errors returned by it.
+// Perhaps we could report those errors asynchronously as [health.Warnable]s?
+func (nb *nodeBackend) Wait(ctx context.Context) error {
+	nb.mu.Lock()
+	readyCh := nb.readyCh
+	nb.mu.Unlock()
+
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	case <-nb.ctx.Done():
+		return context.Cause(nb.ctx)
+	case <-readyCh:
+		return nil
+	}
+}
+
+// shutdown shuts down the [nodeBackend] and cancels its context
+// with the provided cause.
+func (nb *nodeBackend) shutdown(cause error) {
+	nb.shutdownOnce.Do(func() {
+		nb.doShutdown(cause)
+	})
+}
+
+func (nb *nodeBackend) doShutdown(cause error) {
+	nb.mu.Lock()
+	defer nb.mu.Unlock()
+	nb.ctxCancel(cause)
+	nb.readyCh = nil
+	nb.eventClient.Close()
+}
+
 // dnsConfigForNetmap returns a *dns.Config for the given netmap,
 // prefs, client OS version, and cloud hosting environment.
 //

ipn/ipnlocal/node_backend_test.go

@@ -0,0 +1,123 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+package ipnlocal
+
+import (
+	"context"
+	"errors"
+	"testing"
+	"time"
+
+	"tailscale.com/util/eventbus"
+)
+
+func TestNodeBackendReadiness(t *testing.T) {
+	nb := newNodeBackend(t.Context(), eventbus.New())
+
+	// The node backend is not ready until [nodeBackend.ready] is called,
+	// and [nodeBackend.Wait] should fail with [context.DeadlineExceeded].
+	ctx, cancelCtx := context.WithTimeout(context.Background(), 100*time.Millisecond)
+	defer cancelCtx()
+	if err := nb.Wait(ctx); err != ctx.Err() {
+		t.Fatalf("Wait: got %v; want %v", err, ctx.Err())
+	}
+
+	// Start a goroutine to wait for the node backend to become ready.
+	waitDone := make(chan struct{})
+	go func() {
+		if err := nb.Wait(context.Background()); err != nil {
+			t.Errorf("Wait: got %v; want nil", err)
+		}
+		close(waitDone)
+	}()
+
+	// Call [nodeBackend.ready] to indicate that the node backend is now ready.
+	go nb.ready()
+
+	// Once the backend is called, [nodeBackend.Wait] should return immediately without error.
+	if err := nb.Wait(context.Background()); err != nil {
+		t.Fatalf("Wait: got %v; want nil", err)
+	}
+	// And any pending waiters should also be unblocked.
+	<-waitDone
+}
+
+func TestNodeBackendShutdown(t *testing.T) {
+	nb := newNodeBackend(t.Context(), eventbus.New())
+
+	shutdownCause := errors.New("test shutdown")
+
+	// Start a goroutine to wait for the node backend to become ready.
+	// This test expects it to block until the node backend shuts down
+	// and then return the specified shutdown cause.
+	waitDone := make(chan struct{})
+	go func() {
+		if err := nb.Wait(context.Background()); err != shutdownCause {
+			t.Errorf("Wait: got %v; want %v", err, shutdownCause)
+		}
+		close(waitDone)
+	}()
+
+	// Call [nodeBackend.shutdown] to indicate that the node backend is shutting down.
+	nb.shutdown(shutdownCause)
+
+	// Calling it again is fine, but should not change the shutdown cause.
+	nb.shutdown(errors.New("test shutdown again"))
+
+	// After shutdown, [nodeBackend.Wait] should return with the specified shutdown cause.
+	if err := nb.Wait(context.Background()); err != shutdownCause {
+		t.Fatalf("Wait: got %v; want %v", err, shutdownCause)
+	}
+	// The context associated with the node backend should also be cancelled
+	// and its cancellation cause should match the shutdown cause.
+	if err := nb.Context().Err(); !errors.Is(err, context.Canceled) {
+		t.Fatalf("Context.Err: got %v; want %v", err, context.Canceled)
+	}
+	if cause := context.Cause(nb.Context()); cause != shutdownCause {
+		t.Fatalf("Cause: got %v; want %v", cause, shutdownCause)
+	}
+	// And any pending waiters should also be unblocked.
+	<-waitDone
+}
+
+func TestNodeBackendReadyAfterShutdown(t *testing.T) {
+	nb := newNodeBackend(t.Context(), eventbus.New())
+
+	shutdownCause := errors.New("test shutdown")
+	nb.shutdown(shutdownCause)
+	nb.ready() // Calling ready after shutdown is a no-op, but should not panic, etc.
+	if err := nb.Wait(context.Background()); err != shutdownCause {
+		t.Fatalf("Wait: got %v; want %v", err, shutdownCause)
+	}
+}
+
+func TestNodeBackendParentContextCancellation(t *testing.T) {
+	ctx, cancelCtx := context.WithCancel(context.Background())
+	nb := newNodeBackend(ctx, eventbus.New())
+
+	cancelCtx()
+
+	// Cancelling the parent context should cause [nodeBackend.Wait]
+	// to return with [context.Canceled].
+	if err := nb.Wait(context.Background()); !errors.Is(err, context.Canceled) {
+		t.Fatalf("Wait: got %v; want %v", err, context.Canceled)
+	}
+
+	// And the node backend's context should also be cancelled.
+	if err := nb.Context().Err(); !errors.Is(err, context.Canceled) {
+		t.Fatalf("Context.Err: got %v; want %v", err, context.Canceled)
+	}
+}
+
+func TestNodeBackendConcurrentReadyAndShutdown(t *testing.T) {
+	nb := newNodeBackend(t.Context(), eventbus.New())
+
+	// Calling [nodeBackend.ready] and [nodeBackend.shutdown] concurrently
+	// should not cause issues, and [nodeBackend.Wait] should unblock,
+	// but the result of [nodeBackend.Wait] is intentionally undefined.
+	go nb.ready()
+	go nb.shutdown(errors.New("test shutdown"))
+
+	nb.Wait(context.Background())
+}

ipn/serve_test.go

@@ -1,5 +1,6 @@
 // Copyright (c) Tailscale Inc & AUTHORS
 // SPDX-License-Identifier: BSD-3-Clause
+
 package ipn
 
 import (

license_test.go

@@ -0,0 +1,117 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+package tailscaleroot
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"tailscale.com/util/set"
+)
+
+func normalizeLineEndings(b []byte) []byte {
+	return bytes.ReplaceAll(b, []byte("\r\n"), []byte("\n"))
+}
+
+// TestLicenseHeaders checks that all Go files in the tree
+// directory tree have a correct-looking Tailscale license header.
+func TestLicenseHeaders(t *testing.T) {
+	want := normalizeLineEndings([]byte(strings.TrimLeft(`
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+`, "\n")))
+
+	exceptions := set.Of(
+		// Subprocess test harness code
+		"util/winutil/testdata/testrestartableprocesses/main.go",
+		"util/winutil/subprocess_windows_test.go",
+
+		// WireGuard copyright
+		"cmd/tailscale/cli/authenticode_windows.go",
+		"wgengine/router/ifconfig_windows.go",
+
+		// noiseexplorer.com copyright
+		"control/controlbase/noiseexplorer_test.go",
+
+		// Generated eBPF management code
+		"derp/xdp/bpf_bpfeb.go",
+		"derp/xdp/bpf_bpfel.go",
+
+		// Generated kube deepcopy funcs file starts with a Go build tag + an empty line
+		"k8s-operator/apis/v1alpha1/zz_generated.deepcopy.go",
+	)
+
+	err := filepath.Walk(".", func(path string, fi os.FileInfo, err error) error {
+		if err != nil {
+			return fmt.Errorf("path %s: %v", path, err)
+		}
+		if exceptions.Contains(filepath.ToSlash(path)) {
+			return nil
+		}
+		base := filepath.Base(path)
+		switch base {
+		case ".git", "node_modules", "tempfork":
+			return filepath.SkipDir
+		}
+		switch base {
+		case "zsyscall_windows.go":
+			// Generated code.
+			return nil
+		}
+
+		if strings.HasSuffix(base, ".config.ts") {
+			return nil
+		}
+		if strings.HasSuffix(base, "_string.go") {
+			// Generated file from go:generate stringer
+			return nil
+		}
+
+		ext := filepath.Ext(base)
+		switch ext {
+		default:
+			return nil
+		case ".go", ".ts", ".tsx":
+		}
+
+		buf := make([]byte, 512)
+		f, err := os.Open(path)
+		if err != nil {
+			return err
+		}
+		defer f.Close()
+		if n, err := io.ReadAtLeast(f, buf, 512); err != nil && err != io.ErrUnexpectedEOF {
+			return err
+		} else {
+			buf = buf[:n]
+		}
+
+		buf = normalizeLineEndings(buf)
+
+		bufNoTrunc := buf
+		if i := bytes.Index(buf, []byte("\npackage ")); i != -1 {
+			buf = buf[:i]
+		}
+
+		if bytes.Contains(buf, want) {
+			return nil
+		}
+
+		if bytes.Contains(bufNoTrunc, []byte("BSD-3-Clause\npackage ")) {
+			t.Errorf("file %s has license header as a package doc; add a blank line before the package line", path)
+			return nil
+		}
+
+		t.Errorf("file %s is missing Tailscale copyright header:\n\n%s", path, want)
+		return nil
+	})
+	if err != nil {
+		t.Fatalf("Walk: %v", err)
+	}
+}

net/tstun/mtu_test.go

@@ -1,5 +1,6 @@
 // Copyright (c) Tailscale Inc & AUTHORS
 // SPDX-License-Identifier: BSD-3-Clause
+
 package tstun
 
 import (

scripts/check_license_headers.sh

@@ -1,77 +0,0 @@
-#!/bin/sh
-#
-# Copyright (c) Tailscale Inc & AUTHORS
-# SPDX-License-Identifier: BSD-3-Clause
-#
-# check_license_headers.sh checks that all Go files in the given
-# directory tree have a correct-looking Tailscale license header.
-
-check_file() {
-    got=$1
-
-    want=$(cat <<EOF
-// Copyright (c) Tailscale Inc & AUTHORS
-// SPDX-License-Identifier: BSD-3-Clause
-EOF
-    )
-    if [ "$got" = "$want" ]; then
-        return 0
-    fi
-    return 1
-}
-
-if [ $# != 1 ]; then
-    echo "Usage: $0 rootdir" >&2
-    exit 1
-fi
-
-fail=0
-for file in $(find $1 \( -name '*.go' -or -name '*.tsx' -or -name '*.ts' -not -name '*.config.ts' \) -not -path '*/.git/*' -not -path '*/node_modules/*'); do
-    case $file in
-        $1/tempfork/*)
-            # Skip, tempfork of third-party code
-        ;;
-        $1/wgengine/router/ifconfig_windows.go)
-            # WireGuard copyright.
-        ;;
-        $1/cmd/tailscale/cli/authenticode_windows.go)
-            # WireGuard copyright.
-        ;;
-        *_string.go)
-          # Generated file from go:generate stringer
-        ;;
-        $1/control/controlbase/noiseexplorer_test.go)
-          # Noiseexplorer.com copyright.
-        ;;
-        */zsyscall_windows.go)
-            # Generated syscall wrappers
-        ;;
-        $1/util/winutil/subprocess_windows_test.go)
-            # Subprocess test harness code
-        ;;
-        $1/util/winutil/testdata/testrestartableprocesses/main.go)
-            # Subprocess test harness code
-        ;;
-        *$1/k8s-operator/apis/v1alpha1/zz_generated.deepcopy.go)
-            # Generated kube deepcopy funcs file starts with a Go build tag + an empty line
-            header="$(head -5 $file | tail -n+3 )"
-        ;;
-        $1/derp/xdp/bpf_bpfe*.go)
-            # Generated eBPF management code
-        ;;
-        *)
-           header="$(head -2 $file)"
-        ;;
-    esac
-    if [ ! -z "$header" ]; then
-            if ! check_file "$header"; then
-                fail=1
-                echo "${file#$1/} doesn't have the right copyright header:"
-                echo "$header" | sed -e 's/^/    /g'
-            fi
-    fi
-done
-
-if [ $fail -ne 0 ]; then
-    exit 1
-fi

tka/builder_test.go

@@ -5,6 +5,7 @@ package tka
 
 import (
 	"crypto/ed25519"
+	"strings"
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
@@ -90,6 +91,20 @@ func TestAuthorityBuilderRemoveKey(t *testing.T) {
 	if _, err := a.state.GetKey(key2.MustID()); err != ErrNoSuchKey {
 		t.Errorf("GetKey(key2).err = %v, want %v", err, ErrNoSuchKey)
 	}
+
+	// Check that removing the remaining key errors out.
+	b = a.NewUpdater(signer25519(priv))
+	if err := b.RemoveKey(key.MustID()); err != nil {
+		t.Fatalf("RemoveKey(%v) failed: %v", key, err)
+	}
+	updates, err = b.Finalize(storage)
+	if err != nil {
+		t.Fatalf("Finalize() failed: %v", err)
+	}
+	wantErr := "cannot remove the last key"
+	if err := a.Inform(storage, updates); err == nil || !strings.Contains(err.Error(), wantErr) {
+		t.Fatalf("expected Inform() to return error %q, got: %v", wantErr, err)
+	}
 }
 
 func TestAuthorityBuilderSetKeyVote(t *testing.T) {

tka/tka.go

@@ -440,6 +440,13 @@ func aumVerify(aum AUM, state State, isGenesisAUM bool) error {
 			return fmt.Errorf("signature %d: %v", i, err)
 		}
 	}
+
+	if aum.MessageKind == AUMRemoveKey && len(state.Keys) == 1 {
+		if kid, err := state.Keys[0].ID(); err == nil && bytes.Equal(aum.KeyID, kid) {
+			return errors.New("cannot remove the last key in the state")
+		}
+	}
+
 	return nil
 }
 

tsconsensus/authorization.go

@@ -87,29 +87,29 @@ func (a *authorization) Refresh(ctx context.Context) error {
 }
 
 func (a *authorization) AllowsHost(addr netip.Addr) bool {
+	a.mu.Lock()
+	defer a.mu.Unlock()
 	if a.peers == nil {
 		return false
 	}
-	a.mu.Lock()
-	defer a.mu.Unlock()
 	return a.peers.addrs.Contains(addr)
 }
 
 func (a *authorization) SelfAllowed() bool {
+	a.mu.Lock()
+	defer a.mu.Unlock()
 	if a.peers == nil {
 		return false
 	}
-	a.mu.Lock()
-	defer a.mu.Unlock()
 	return a.peers.status.Self.Tags != nil && views.SliceContains(*a.peers.status.Self.Tags, a.tag)
 }
 
 func (a *authorization) AllowedPeers() views.Slice[*ipnstate.PeerStatus] {
+	a.mu.Lock()
+	defer a.mu.Unlock()
 	if a.peers == nil {
 		return views.Slice[*ipnstate.PeerStatus]{}
 	}
-	a.mu.Lock()
-	defer a.mu.Unlock()
 	return views.SliceOf(a.peers.statuses)
 }
 

tsweb/promvarz/promvarz_test.go

@@ -1,5 +1,6 @@
 // Copyright (c) Tailscale Inc & AUTHORS
 // SPDX-License-Identifier: BSD-3-Clause
+
 package promvarz
 
 import (

util/eventbus/client.go

@@ -113,15 +113,16 @@ func (c *Client) shouldPublish(t reflect.Type) bool {
 // Subscribe requests delivery of events of type T through the given
 // Queue. Panics if the queue already has a subscriber for T.
 func Subscribe[T any](c *Client) *Subscriber[T] {
-	return newSubscriber[T](c.subscribeState())
+	r := c.subscribeState()
+	s := newSubscriber[T](r)
+	r.addSubscriber(s)
+	return s
 }
 
 // Publisher returns a publisher for event type T using the given
 // client.
 func Publish[T any](c *Client) *Publisher[T] {
-	ret := newPublisher[T](c)
+	p := newPublisher[T](c)
-	c.mu.Lock()
+	c.addPublisher(p)
-	defer c.mu.Unlock()
+	return p
-	c.pub.Add(ret)
-	return ret
 }

util/eventbus/publish.go

@@ -21,11 +21,7 @@ type Publisher[T any] struct {
 }
 
 func newPublisher[T any](c *Client) *Publisher[T] {
-	ret := &Publisher[T]{
+	return &Publisher[T]{client: c}
-		client: c,
-	}
-	c.addPublisher(ret)
-	return ret
 }
 
 // Close closes the publisher.

util/eventbus/subscribe.go

@@ -91,7 +91,7 @@ func (q *subscribeState) pump(ctx context.Context) {
 			}
 		} else {
 			// Keep the cases in this select in sync with
-			// Subscriber.dispatch below. The only different should be
+			// Subscriber.dispatch below. The only difference should be
 			// that this select doesn't deliver queued values to
 			// anyone, and unconditionally accepts new values.
 			select {
@@ -134,9 +134,10 @@ func (s *subscribeState) subscribeTypes() []reflect.Type {
 	return ret
 }
 
-func (s *subscribeState) addSubscriber(t reflect.Type, sub subscriber) {
+func (s *subscribeState) addSubscriber(sub subscriber) {
 	s.outputsMu.Lock()
 	defer s.outputsMu.Unlock()
+	t := sub.subscribeType()
 	if s.outputs[t] != nil {
 		panic(fmt.Errorf("double subscription for event %s", t))
 	}
@@ -183,15 +184,10 @@ type Subscriber[T any] struct {
 }
 
 func newSubscriber[T any](r *subscribeState) *Subscriber[T] {
-	t := reflect.TypeFor[T]()
+	return &Subscriber[T]{
-
-	ret := &Subscriber[T]{
 		read:       make(chan T),
-		unregister: func() { r.deleteSubscriber(t) },
+		unregister: func() { r.deleteSubscriber(reflect.TypeFor[T]()) },
 	}
-	r.addSubscriber(t, ret)
-
-	return ret
 }
 
 func newMonitor[T any](attach func(fn func(T)) (cancel func())) *Subscriber[T] {

util/must/must.go

@@ -23,3 +23,11 @@ func Get[T any](v T, err error) T {
 	}
 	return v
 }
+
+// Get2 returns v1 and v2 as is. It panics if err is non-nil.
+func Get2[T any, U any](v1 T, v2 U, err error) (T, U) {
+	if err != nil {
+		panic(err)
+	}
+	return v1, v2
+}

wgengine/magicsock/magicsock.go

@@ -63,6 +63,7 @@ import (
 	"tailscale.com/util/set"
 	"tailscale.com/util/testenv"
 	"tailscale.com/util/usermetric"
+	"tailscale.com/wgengine/filter"
 	"tailscale.com/wgengine/wgint"
 )
 
@@ -502,6 +503,30 @@ func (o *Options) derpActiveFunc() func() {
 	return o.DERPActiveFunc
 }
 
+// NodeAddrsHostInfoUpdate represents an update event of the addresses and
+// [tailcfg.HostInfoView] for a node set. This event is published over an
+// [eventbus.Bus]. [magicsock.Conn] is the sole subscriber as of 2025-06. If
+// you are adding more subscribers consider moving this type out of magicsock.
+type NodeAddrsHostInfoUpdate struct {
+	NodesByID map[tailcfg.NodeID]NodeAddrsHostInfo
+	Complete  bool // true if NodesByID contains all known nodes, false if it may be a subset
+}
+
+// NodeAddrsHostInfo represents the addresses and [tailcfg.HostinfoView] for a
+// Tailscale node.
+type NodeAddrsHostInfo struct {
+	Addresses views.Slice[netip.Prefix]
+	Hostinfo  tailcfg.HostinfoView
+}
+
+// FilterUpdate represents an update event for a [*filter.Filter]. This event is
+// signaled over an [eventbus.Bus]. [magicsock.Conn] is the sole subscriber as
+// of 2025-06. If you are adding more subscribers consider moving this type out
+// of magicsock.
+type FilterUpdate struct {
+	*filter.Filter
+}
+
 // newConn is the error-free, network-listening-side-effect-free based
 // of NewConn. Mostly for tests.
 func newConn(logf logger.Logf) *Conn {
@@ -535,6 +560,20 @@ func newConn(logf logger.Logf) *Conn {
 	return c
 }
 
+// consumeEventbusTopic consumes events from sub and passes them to
+// handlerFn until sub.Done() is closed.
+func consumeEventbusTopic[T any](sub *eventbus.Subscriber[T], handlerFn func(t T)) {
+	defer sub.Close()
+	for {
+		select {
+		case evt := <-sub.Events():
+			handlerFn(evt)
+		case <-sub.Done():
+			return
+		}
+	}
+}
+
 // NewConn creates a magic Conn listening on opts.Port.
 // As the set of possible endpoints for a Conn changes, the
 // callback opts.EndpointsFunc is called.
@@ -562,17 +601,17 @@ func NewConn(opts Options) (*Conn, error) {
 		c.eventClient = c.eventBus.Client("magicsock.Conn")
 
 		pmSub := eventbus.Subscribe[portmapper.Mapping](c.eventClient)
-		go func() {
+		go consumeEventbusTopic(pmSub, func(_ portmapper.Mapping) {
-			defer pmSub.Close()
+			c.onPortMapChanged()
-			for {
+		})
-				select {
+		filterSub := eventbus.Subscribe[FilterUpdate](c.eventClient)
-				case <-pmSub.Events():
+		go consumeEventbusTopic(filterSub, func(t FilterUpdate) {
-					c.onPortMapChanged()
+			// TODO(jwhited): implement
-				case <-pmSub.Done():
+		})
-					return
+		nodeSub := eventbus.Subscribe[NodeAddrsHostInfoUpdate](c.eventClient)
-				}
+		go consumeEventbusTopic(nodeSub, func(t NodeAddrsHostInfoUpdate) {
-			}
+			// TODO(jwhited): implement
-		}()
+		})
 
 		// Disable the explicit callback from the portmapper, the subscriber handles it.
 		onPortMapChanged = nil
@@ -2798,6 +2837,10 @@ func (c *connBind) Close() error {
 		return nil
 	}
 	c.closed = true
+	// Close the [eventbus.Client].
+	if c.eventClient != nil {
+		c.eventClient.Close()
+	}
 	// Unblock all outstanding receives.
 	c.pconn4.Close()
 	c.pconn6.Close()