chore(deps): update renovate/renovate docker tag to v43.212.4

.woodpecker/pr-build.yaml

@@ -9,31 +9,18 @@
 # Reports pass/fail status back to Gitea, so it shows up as a required check on
 # the PR.
 
-# Changes that can't affect the image don't trigger the build: docs and the
-# RouterOS-side script (routeros/**: lives on the router, not in the image).
-# NOTE: if Gitea is ever configured to REQUIRE this check for merging, a
-# PR touching only excluded files will have no check at all — exempt such PRs
-# or merge manually. Renovate PRs always touch the Dockerfile or pipeline
-# files, so the automerge gate is unaffected by these exclusions.
 when:
   - event: pull_request
-    path:
-      exclude: &non_image_paths
-        - '**/*.md'
-        - 'docs/**'
-        - 'routeros/**'
-        - 'renovate.json'
   - event: push
     branch: main
-    path:
-      exclude: *non_image_paths
 
 steps:
   - name: Build all arches (no push)
     image: woodpeckerci/plugin-docker-buildx:6.1.0
     privileged: true
     settings:
+      repo: mikrotik-tailscale
       platforms: linux/amd64,linux/arm64,linux/arm/v7
-      dry_run: true
+      dry-run: true
       build_args:
         - OCI_VERSION=ci-${CI_COMMIT_SHA}

.woodpecker/release-tag.yaml

@@ -13,19 +13,9 @@
 # unchanged, so no tag is created and nothing is released — they ride along
 # with the next Tailscale bump or manual tag.
 
-# Skipped for pushes that can't introduce a new Tailscale version:
-# TAILSCALE_VERSION lives in the Dockerfile, so a push touching only docs or
-# the RouterOS-side script can never produce a new version to tag (the job
-# would just no-op after spinning up OpenBao + git containers).
 when:
   - event: push
     branch: main
-    path:
-      exclude:
-        - '**/*.md'
-        - 'docs/**'
-        - 'routeros/**'
-        - 'renovate.json'
 
 steps:
   - name: Get git token from OpenBao
@@ -44,7 +34,7 @@ steps:
       - bao kv get -mount secret -field RENOVATE_TOKEN renovate > /woodpecker/git_token
 
   - name: Auto-tag mt.1 on Tailscale bump
-    image: alpine/git:v2.54.0
+    image: alpine/git:v2.52.0
     environment:
       CI_REPO_URL: https://gitea.lumpiasty.xyz/lumpiasty/mikrotik-tailscale.git
     commands:

.woodpecker/renovate.yaml

@@ -46,7 +46,7 @@ steps:
       - bao kv get -mount secret -field GITHUB_COM_TOKEN renovate > /woodpecker/github_com_token
   - name: renovate
     # Renovate's built-in "woodpecker" manager tracks this image automatically.
-    image: renovate/renovate:43.227.0
+    image: renovate/renovate:43.212.4
     environment:
       # --- platform / target ---
       RENOVATE_PLATFORM: gitea
@@ -58,12 +58,8 @@ steps:
       # Use the committed renovate.json; don't open an onboarding PR.
       RENOVATE_ONBOARDING: "false"
       RENOVATE_REQUIRE_CONFIG: "optional"
-      # Git identity for the branches/commits Renovate creates. MUST match the
-      # bot's Gitea account email: platform actions (automerge merge commits,
-      # "update branch") are attributed to the account email, and Renovate
-      # flags branches containing commits from unrecognized emails as
-      # "edited by someone else" and stops rebasing them.
-      RENOVATE_GIT_AUTHOR: "Renovate Bot <renovate@lumpiasty.xyz>"
+      # Git identity for the branches/commits Renovate creates.
+      RENOVATE_GIT_AUTHOR: "Renovate Bot <renovate@localhost>"
       # GitHub token (read-only, no repo access) lets Renovate fetch release
       # notes / changelogs and avoids GitHub API rate limits for the
       # github-releases datasource (tailscale). Optional but recommended.

Dockerfile

@@ -1,4 +1,4 @@
-# syntax=docker/dockerfile:1.25.0@sha256:0adf442eae370b6087e08edc7c50b552d80ddf261576f4ebd6421006b2461f12
+# syntax=docker/dockerfile:1.24.0@sha256:87999aa3d42bdc6bea60565083ee17e86d1f3339802f543c0d03998580f9cb89
 # =============================================================================
 # Multi-architecture build
 # =============================================================================
@@ -12,27 +12,14 @@
 # it would need a glibc (Debian) base and produces a much larger image. See
 # README for details if you need it.
 #
-# Both the Go (Tailscale) stage and the C (busybox) stage cross-compile: they
-# always run NATIVELY on the build host ($BUILDPLATFORM) and produce binaries
-# for $TARGETPLATFORM. This eliminates QEMU emulation entirely from the build,
-# which is the main source of slowness in multi-arch builds. Only the final
-# scratch stage pulls in the target-arch-specific layers (CA certs, busybox
-# rootfs) which are just file copies with no emulated execution.
-#
-# Cross-compilation for C (busybox) is provided by tonistiigi/xx, which
-# configures clang+lld as a cross-compiler and installs musl headers for the
-# target arch via xx-apk.
-
-# =============================================================================
-# xx: Dockerfile cross-compilation helpers (provides xx-clang, xx-apk, etc.)
-# =============================================================================
-# renovate: datasource=docker depName=tonistiigi/xx versioning=docker
-FROM --platform=$BUILDPLATFORM tonistiigi/xx:1.9.0@sha256:c64defb9ed5a91eacb37f96ccc3d4cd72521c4bd18d5442905b95e2226b0e707 AS xx
+# The Go builder cross-compiles, so it always runs NATIVELY on the build host
+# ($BUILDPLATFORM) for speed; only the busybox stage and the final image run on
+# the target platform.
 
 # =============================================================================
 # Stage 1: Build Tailscale combined binary (cross-compiled, runs natively)
 # =============================================================================
-FROM --platform=$BUILDPLATFORM golang:1.26.4-alpine@sha256:f1ddd9fe14fffc091dd98cb4bfa999f32c5fc77d2f2305ea9f0e2595c5437c14 AS builder
+FROM --platform=$BUILDPLATFORM golang:1.26.4-alpine@sha256:f23e8b227fb4493eabe03bede4d5a32d04092da71962f1fb79b5f7d1e6c2a17f AS builder
 
 # renovate: datasource=github-releases depName=tailscale packageName=tailscale/tailscale versioning=semver
 ARG TAILSCALE_VERSION=v1.98.5
@@ -53,23 +40,6 @@ RUN git clone --depth 1 --branch ${TAILSCALE_VERSION} \
 
 WORKDIR /src/tailscale
 
-# Inject a stderr verbosity filter into the tailscaled package.
-#
-# With logtail compiled out (ts_omit_logtail), tailscaled never installs
-# logpolicy (see `if buildfeatures.HasLogTail` in cmd/tailscaled/tailscaled.go),
-# so log output goes raw to stderr: the [v1]/[v2] verbosity tags embedded in
-# messages are neither parsed nor filtered, and --verbose has NO effect. The
-# result is constant log spam in the RouterOS container log (filter
-# "Accept: TCP" verdicts, "netcheck: [v1] report", "wg: [v2]" handshakes and
-# keepalives) — see tailscale/tailscale#12158 and #1548.
-#
-# The injected file (build-tagged ts_omit_logtail, so it's a no-op if logtail
-# is ever re-enabled) registers a log writer in init() that drops lines
-# carrying a [v1]+ tag, restoring the equivalent of logtail's StderrLevel=0
-# default. Setting TS_LOG_VERBOSITY=1 (or higher) in the container environment
-# disables the filter at runtime for debugging — no rebuild needed.
-COPY patches/stderr_verbosity_filter.go cmd/tailscaled/
-
 # Build a minimal combined binary (tailscale CLI + tailscaled daemon in one file).
 #
 # Tag strategy — ALLOWLIST, not blocklist:
@@ -105,59 +75,6 @@ COPY patches/stderr_verbosity_filter.go cmd/tailscaled/
 #                         waiting for completion") WITHOUT printing the auth URL
 #                         or confirming success. Including it makes interactive
 #                         'up' behave normally (blocks, prints login URL).
-#   netstack            — gVisor userspace network stack. Counter-intuitively
-#                         REQUIRED even though the router uses a real kernel TUN
-#                         (NOT --tun=userspace-networking). In v1.98.5 the
-#                         100.100.100.100:53 MagicDNS listener is served ONLY by
-#                         netstack's handleLocalPackets, installed via
-#                         PreFilterPacketOutboundToWireGuardNetstackIntercept.
-#                         The non-netstack "engine" interceptor that the wrap.go
-#                         comments claim handles quad-100 "if netstack is not
-#                         installed" does NOT actually do so on Linux (its body
-#                         only reflects loopback on darwin/ios/plan9, else
-#                         Accept). So with ts_omit_netstack, NOTHING absorbs
-#                         packets to 100.100.100.100: queries fall through to
-#                         WireGuard, no peer owns that IP, and even tailnet-name
-#                         resolution (and 'ping host.tailnet.ts.net') times out.
-#                         The 'dns' tag links the resolver but nothing routes
-#                         packets to it without netstack — the two tags are
-#                         independent (dns has no Dep on netstack). Omitting
-#                         netstack ALSO triggered a panic("unreachable") in
-#                         net/tstun.invertGSOChecksum on the exit-node inject
-#                         path (HasNetstack=const false made the guard always
-#                         panic); enabling netstack makes that guard dead code,
-#                         fixing the crash as a side effect. Cost (arm64, vs a
-#                         netstack-omitted build): ~+0.5 MB extracted on flash
-#                         and ~+2.3 MB resident RAM after UPX decompression —
-#                         measured, acceptable for a 16 MB-flash router.
-#   gro                 — Generic Receive Offload (perf). Depends on netstack;
-#                         pulled in with it. Small, and improves throughput on
-#                         the netstack DNS/inject path.
-#   peerapiserver       — REQUIRED to be a functional exit node. In v1.98.5
-#                         'advertiseexitnode' DECLARES a dependency on
-#                         peerapiserver (featuretags.go Deps, "to run the ExitDNS
-#                         server"), but this build's allowlist works by stripping
-#                         individual ts_omit_ tags and does NOT re-resolve Deps —
-#                         so featuretags --min still emitted ts_omit_peerapiserver
-#                         and our advertiseexitnode opt-in alone left it omitted.
-#                         peerapiserver gates the entire PeerAPI HTTP server,
-#                         including the /dns-query DoH endpoint (peerapi.go,
-#                         guarded by buildfeatures.HasPeerAPIServer). Without it
-#                         initPeerAPIListenerLocked() returns early: the node
-#                         never advertises the PeerAPIDNS service, so exit-node
-#                         CLIENTS' exitNodeCanProxyDNS(thisNode) returns false.
-#                         With no tailnet global nameserver configured, the
-#                         client's resolver then has an empty Routes["."] and
-#                         returns an INSTANT authoritative SERVFAIL locally
-#                         (forwarder.go servfailResponse, aa=1, 0 ms, no I/O) —
-#                         i.e. devices using this router as their exit node could
-#                         not resolve PUBLIC names. Including peerapiserver makes
-#                         the node serve the exit-node DoH DNS proxy, so clients
-#                         get public DNS automatically (the normal exit-node
-#                         behavior) with no tailnet DNS config required.
-#                         peerapiserver has NO Deps and pulls in no large
-#                         subsystems — a small addition. (outboundproxy is NOT
-#                         needed for this and stays omitted.)
 #
 # Everything else remains omitted, including (rationale):
 #   clientupdate  — DELIBERATELY removed. The built-in updater would download
@@ -182,11 +99,9 @@ COPY patches/stderr_verbosity_filter.go cmd/tailscaled/
 #                   which is exactly the flash wear we want to avoid.
 #   logtail       — no persistent log writes to flash; also pass
 #                   --no-logs-no-support at runtime
+#   netstack+gro  — userspace networking; router uses kernel TUN
 #   ssh           — not needed; access via MikroTik SSH + tailscale CLI
 #   all GUI/desktop/cloud/k8s features — irrelevant for a headless router
-#
-# NOTE: netstack/gro are NOT in this omit list — see the opted-in section above
-# for why MagicDNS quad-100 serving structurally requires them in v1.98.5.
 
 RUN mkdir -p /out && \
     ALL_OMIT=$(GOOS= GOARCH= go run ./cmd/featuretags --min --add=osrouter) && \
@@ -203,9 +118,6 @@ RUN mkdir -p /out && \
           -e 's/ts_omit_iptables,\{0,1\}//g' \
           -e 's/ts_omit_unixsocketidentity,\{0,1\}//g' \
           -e 's/ts_omit_ipnbus,\{0,1\}//g' \
-          -e 's/ts_omit_netstack,\{0,1\}//g' \
-          -e 's/ts_omit_gro,\{0,1\}//g' \
-          -e 's/ts_omit_peerapiserver,\{0,1\}//g' \
           -e 's/,$//' \
     ) && \
     echo "Build tags: ${TAGS}" && \
@@ -264,7 +176,7 @@ RUN printf '%s\n' \
     chmod +x /out/usrlocalbin/entrypoint.sh
 
 # =============================================================================
-# Stage 2: Custom minimal busybox (cross-compiled, runs natively on build host)
+# Stage 2: Custom minimal busybox
 # =============================================================================
 # The official busybox:musl image ships all ~404 applets at ~1.24 MB. For a
 # debug shell on a flash-constrained router we only need ~100 applets, so we
@@ -281,56 +193,15 @@ RUN printf '%s\n' \
 # acceptable for an occasional debug shell. RouterOS stores the EXTRACTED
 # rootfs on disk (overlayfs), so the ~190 kB UPX saving is real on-disk space.
 #
-# This stage runs NATIVELY on the build host (--platform=$BUILDPLATFORM) and
-# cross-compiles busybox for the target architecture using clang+lld via the
-# tonistiigi/xx helpers. This eliminates QEMU emulation from the busybox build,
-# which was the main source of slowness for arm64/arm/v7 targets.
-#
-# Cross-compilation setup:
-#   - xx-apk installs musl-dev and linux-headers for the TARGET arch under
-#     /<triple> (a secondary sysroot), while clang/lld/upx/make stay native.
-#   - xx-clang --setup-target-triple creates <triple>-clang / <triple>-cc
-#     aliases in PATH that busybox's Makefile picks up via CROSS_COMPILE.
-#   - Busybox make receives:
-#       CROSS_COMPILE=<triple>-   → picks up <triple>-clang (from xx aliases)
-#       CC=clang                  → use clang (aliased target via CROSS_COMPILE)
-#       HOSTCC=gcc                → compile host helper tools with native gcc
-#   - upx (native x86_64 binary) can compress target-arch binaries since UPX
-#     operates on the ELF file format regardless of the target ISA.
-#
-# Applet symlink probing: for native-arch builds the probe runs directly;
-# for cross-compiled binaries we use QEMU user-mode emulation (from binfmt)
-# only for this one lightweight probe step (busybox --help per applet), not
-# for the compile itself. The probe can alternatively be skipped by using
-# a pre-enumerated applet list, but the current approach is simpler.
-FROM --platform=$BUILDPLATFORM alpine:3.24.1@sha256:28bd5fe8b56d1bd048e5babf5b10710ebe0bae67db86916198a6eec434943f8b AS busybox
-
-# Copy xx cross-compilation helpers (xx-clang, xx-apk, xx-info, etc.)
-COPY --from=xx / /
+# This stage runs on the TARGET platform (no --platform override): gcc then
+# produces native target-arch binaries directly. Under buildx this is
+# transparently emulated via binfmt/QEMU for non-native targets.
+FROM alpine:3.23.4@sha256:5b10f432ef3da1b8d4c7eb6c487f2f5a8f096bc91145e68878dd4a5019afde11 AS busybox
 
 # renovate: datasource=docker depName=busybox versioning=docker
-ARG BUSYBOX_VERSION=1.38.0
+ARG BUSYBOX_VERSION=1.37.0
 
-# Target platform ARGs (provided automatically by buildx).
-ARG TARGETPLATFORM
-ARG TARGETARCH
-ARG TARGETVARIANT
-
-# Native build tools (clang/lld for cross-compiling; gcc/make/upx run natively).
-# xx-apk installs the target-arch sysroot: musl-dev (C library headers + CRT),
-# gcc (provides crtbeginS.o/crtendS.o and libgcc needed by clang on Alpine),
-# and linux-headers (required by busybox for <linux/*.h> / <net/*.h>).
-RUN apk add --no-cache \
-        clang \
-        lld \
-        llvm \
-        gcc \
-        make \
-        wget \
-        bzip2 \
-        perl \
-        upx && \
-    xx-apk add --no-cache musl-dev gcc linux-headers
+RUN apk add --no-cache build-base linux-headers wget bzip2 perl upx
 
 RUN wget -q https://busybox.net/downloads/busybox-${BUSYBOX_VERSION}.tar.bz2 \
  && tar xf busybox-${BUSYBOX_VERSION}.tar.bz2
@@ -338,34 +209,7 @@ WORKDIR /busybox-${BUSYBOX_VERSION}
 
 # allnoconfig = every feature OFF; then enable only the curated applet set.
 COPY busybox-applets.config /tmp/applets.config
-# Set up xx cross-compiler aliases (<triple>-clang, <triple>-cc, etc.) and
-# build busybox.
-#
-# Key make variables:
-#   ARCH           — busybox ARCH; must match the cross-target, not the build
-#                    host. busybox's Makefile would otherwise read SUBARCH from
-#                    `uname -m` (the BUILD host's arch) which is wrong when
-#                    cross-compiling. We map TARGETARCH to busybox's arch name.
-#                    busybox uses -include arch/$(ARCH)/Makefile; missing arch
-#                    dirs are silently ignored, so any value is safe.
-#   CC             — busybox defaults to $(CROSS_COMPILE)gcc. We override CC to
-#                    the full <triple>-clang path so it resolves to the xx alias
-#                    (which sets --target and --sysroot for the cross-compiler).
-#                    Setting CC= avoids needing a <triple>-gcc symlink.
-#   HOSTCC         — native compiler for host-side build tools (scripts/kconfig,
-#                    gen_build_files, etc.); must NOT be the cross-compiler.
-#   SKIP_STRIP     — defer stripping to after symlink probing (we strip below
-#                    with llvm-strip, which handles any target ELF arch).
-RUN xx-clang --setup-target-triple && \
-    CROSS=$(xx-info triple) && \
-    # Map TARGETARCH to the busybox ARCH value.
-    case "${TARGETARCH}" in \
-      amd64)  BUSYBOX_ARCH=x86_64 ;; \
-      arm64)  BUSYBOX_ARCH=aarch64 ;; \
-      arm)    BUSYBOX_ARCH=arm ;; \
-      *)      BUSYBOX_ARCH=${TARGETARCH} ;; \
-    esac && \
-    make allnoconfig ARCH="${BUSYBOX_ARCH}" && \
+RUN make allnoconfig && \
     while read -r sym; do \
       case "$sym" in ''|\#*) continue ;; esac; \
       if grep -q "^# CONFIG_${sym} is not set" .config; then \
@@ -374,15 +218,9 @@ RUN xx-clang --setup-target-triple && \
         echo "CONFIG_${sym}=y" >> .config; \
       fi; \
     done < /tmp/applets.config && \
-    yes "" | make oldconfig ARCH="${BUSYBOX_ARCH}" >/dev/null 2>&1 && \
-    make -j"$(nproc)" \
-        ARCH="${BUSYBOX_ARCH}" \
-        CROSS_COMPILE="${CROSS}-" \
-        CC="${CROSS}-clang" \
-        HOSTCC=gcc \
-        SKIP_STRIP=y \
-        >/dev/null 2>&1 && \
-    llvm-strip busybox
+    yes "" | make oldconfig >/dev/null 2>&1 && \
+    make -j"$(nproc)" >/dev/null 2>&1 && \
+    strip busybox
 
 # Lay out a minimal rootfs with busybox + an applet symlink per applet.
 # Symlinks (argv[0] dispatch) are how busybox selects an applet and make the
@@ -392,10 +230,6 @@ RUN xx-clang --setup-target-triple && \
 # for non-applet symbols like FEATURE_* / STATIC, which we filter out).
 # We generate symlinks from the UNCOMPRESSED binary (so the probe is reliable),
 # then UPX-compress the binary in place afterwards.
-#
-# Note: probing cross-compiled binaries requires binfmt/QEMU user-mode. This
-# is only a lightweight per-applet help-flag check, not a full emulated build.
-# If QEMU is unavailable in CI, replace the probe with a static applet list.
 RUN mkdir -p /rootfs/bin && \
     grep '^CONFIG_.*=y' .config \
       | sed -e 's/^CONFIG_//' -e 's/=y$//' \

README.md

@@ -70,7 +70,6 @@ ARMv5 (hEX Refresh / hAP ax S) is **not** supported — see
 |---|---|
 | `Dockerfile` | Multi-stage, multi-arch build (cross-compiled Go + custom busybox) |
 | `busybox-applets.config` | Curated busybox applet set |
-| `patches/` | Source files injected into the Tailscale tree at build time (stderr verbosity filter) |
 | `build.sh` | Build all/one arch, optionally export per-arch tarballs |
 | `routeros/update-tailscale.rsc` | RouterOS auto-update script (digest compare + recreate) |
 | `.woodpecker/` | CI: Renovate cron, release tagging, multi-arch publish |

build.sh

@@ -12,8 +12,7 @@
 #
 # Requirements:
 #   - docker with buildx
-#   - For non-native targets: binfmt/QEMU emulators registered for the applet
-#     symlink probe step (a minor step; the full C/Go compile is native):
+#   - For non-native targets: binfmt/QEMU emulators registered, e.g.:
 #       docker run --privileged --rm tonistiigi/binfmt --install arm64,arm
 set -eu
 

docs/DESIGN.md

@@ -15,26 +15,22 @@ Measured flattened rootfs for the arm64 image:
 
 | Component | On-disk size |
 |---|---|
-| `tailscale.combined` (UPX-compressed) | ~3.47 MB |
+| `tailscale.combined` (UPX-compressed) | ~2.98 MB |
 | custom static busybox (UPX, ~100 applets) | ~218 kB |
 | CA certificates | ~213 kB |
-| **Total extracted rootfs** | **~3.9 MB** |
+| **Total extracted rootfs** | **~3.4 MB** |
 
-The `tailscale.combined` figure includes `netstack` (gVisor), which adds
-~0.5 MB on disk over a netstack-omitted build — a deliberate inclusion, see
-[Why netstack is required (even with a kernel TUN)](#why-netstack-is-required-even-with-a-kernel-tun).
-
-(The compressed image / transfer tarball is ~3.8–4.3 MB depending on arch.)
+(The compressed image / transfer tarball is ~3.3–4.3 MB depending on arch.)
 
 | Arch | Image (compressed) |
 |---|---|
-| amd64  | ~4.3 MB |
-| arm64  | ~4.0 MB |
-| arm/v7 | ~4.0 MB |
+| amd64  | ~4.2 MB |
+| arm64  | ~3.5 MB |
+| arm/v7 | ~3.5 MB |
 
-On a deployed RouterOS device the container consumes **~4.2 MiB of flash**
+On a deployed RouterOS device the container consumes **~3.7 MiB of flash**
 (measured by `free-hdd-space` delta). Note that `du` *inside* the container
-reports roughly double that (~8 MB) — that is RouterOS block-allocation
+reports roughly double that (~7 MB) — that is RouterOS block-allocation
 rounding, **not** real usage or duplication; see
 [Avoiding overlayfs layer duplication](#avoiding-overlayfs-layer-duplication)
 for how to measure correctly.
@@ -122,13 +118,13 @@ delta**, not `du`:
 /system/resource/print     # note free-hdd-space before and after adding the container
 ```
 
-The container should consume **~4.2 MiB** of flash (e.g. 94.6 → 90.4 MiB free).
+The container should consume **~3.7 MiB** of flash (e.g. 94.6 → 90.9 MiB free).
 
 Do **not** trust `du` inside the container for this. Busybox `du` reports
-*allocated blocks*, and RouterOS's container store rounds the ~3.5 MB binary up
-to ~7 MB of blocks — so `du -sx /` reports ~8 MB even though real flash use is
-~4.2 MB. `ls -la /usr/local/bin` confirms the binary's true content size
-(~3.5 MB) and that it is a single file with two symlinks (no duplication).
+*allocated blocks*, and RouterOS's container store rounds a ~3 MB file up to
+~6 MB of blocks — so `du -sx /` reports ~7 MB even though real flash use is
+~3.7 MB. `ls -la /usr/local/bin` confirms the binary's true content size
+(~3.1 MB) and that it is a single file with two symlinks (no duplication).
 The image itself carries the binary in exactly one layer (verified at the blob
 level); the inflation is purely the filesystem's block accounting.
 
@@ -153,9 +149,7 @@ that's a separate build, not just a `--platform` change.
 | `advertise-routes` | Expose LAN subnets to the tailnet |
 | `use-exit-node` | Route the router's own traffic via a remote exit node |
 | `accept-routes` | Receive subnet routes from other tailnet nodes |
-| DNS / MagicDNS | Resolve `*.ts.net` names (resolver + resolv.conf manager). **Note:** serving `100.100.100.100` also requires `netstack` — see [Why netstack is required (even with a kernel TUN)](#why-netstack-is-required-even-with-a-kernel-tun) |
-| `netstack` + `gro` | gVisor userspace stack. Counter-intuitively **required** to serve MagicDNS on `100.100.100.100`, even though the router uses a real kernel TUN — see [Why netstack is required (even with a kernel TUN)](#why-netstack-is-required-even-with-a-kernel-tun) |
-| `peerapiserver` | Serves the PeerAPI, including the `/dns-query` DoH endpoint that lets **exit-node clients resolve public DNS automatically**. A declared dependency of `advertise-exit-node` that the allowlist didn't pull in — see [Why peerapiserver is required for exit-node DNS](#why-peerapiserver-is-required-for-exit-node-dns) |
+| DNS / MagicDNS | Resolve `*.ts.net` names |
 | portmapper (NAT-PMP/PCP/UPnP) | Punch through upstream NAT |
 | listenrawdisco | Raw socket disco for better NAT traversal |
 | health | Powers `tailscale status` output |
@@ -170,8 +164,9 @@ that's a separate build, not just a `--platform` change.
 |---|---|
 | `clientupdate` | **Deliberately removed** — see [Why the built-in updater is removed](#why-the-built-in-updater-is-removed) |
 | `cachenetmap` | **Deliberately removed** — see [Why netmap disk-caching is removed](#why-netmap-disk-caching-is-removed) |
-| `logtail` | Would attempt persistent log writes; wear flash. Removing it also removes stderr verbosity filtering — restored by an injected filter, see [Log verbosity filtering](#log-verbosity-filtering) |
+| `logtail` | Would attempt persistent log writes; wear flash |
 | `netlog` | Network flow logging; separate concern |
+| `netstack` + `gro` | Userspace/gVisor networking; router uses kernel TUN |
 | `ssh` | Access via MikroTik SSH + `tailscale` CLI instead |
 | `linuxdnsfight` | inotify on `/etc/resolv.conf`; no systemd in container |
 | `networkmanager` / `resolved` / `dbus` / `sdnotify` | No systemd stack in container |
@@ -231,206 +226,6 @@ the in-memory resilience (the common case) while eliminating per-netmap flash
 writes. Only `tailscaled.state` (written on auth / key rotation) ever touches
 flash.
 
-### Why netstack is required (even with a kernel TUN)
-
-This is the least obvious inclusion in the build, so it is documented in full.
-
-`netstack` is Tailscale's embedded **gVisor userspace TCP/IP stack**. The
-natural assumption — and what earlier versions of this build acted on — is that
-a router which owns a **real kernel TUN device** (it is *not* run with
-`--tun=userspace-networking`) has no use for a userspace stack, so `netstack`
-(and its dependent `gro`) can be omitted to save space. That assumption is
-**wrong for one specific, important path: MagicDNS.**
-
-**MagicDNS on `100.100.100.100` is served only by netstack.** In Tailscale
-v1.98.5 the in-process listener for the Tailscale service IP
-(`100.100.100.100:53`, UDP) is installed exclusively by netstack's
-`handleLocalPackets`, wired into the TUN wrapper as
-`PreFilterPacketOutboundToWireGuardNetstackIntercept`
-(`wgengine/netstack/netstack.go`). When a packet leaves the host toward
-`100.100.100.100`, this hook absorbs it into the gVisor stack, whose UDP-53
-acceptor runs the MagicDNS resolver.
-
-**The "engine fallback" does not actually exist.** The TUN wrapper consults a
-second hook, `PreFilterPacketOutboundToWireGuardEngineIntercept`, and a comment
-in `net/tstun/wrap.go` claims it "primarily handles quad-100 if netstack is not
-installed." In v1.98.5 that comment is **false on Linux**: the engine
-`handleLocalPackets` (`wgengine/userspace.go`) only reflects loopback on
-darwin/ios/plan9 and otherwise returns `Accept` — it never touches
-`100.100.100.100`. So with `ts_omit_netstack` there is **no** code that absorbs
-quad-100 packets at all.
-
-**`dns` and `netstack` are independent tags.** The `dns` feature (which this
-build opts in) links the resolver and the `/etc/resolv.conf` manager, but it has
-no dependency on `netstack` and does **not** install any quad-100 transport.
-The net result of `dns` on + `netstack` off is a resolver that is correctly
-wired up but that **never receives any packets** — the worst kind of silent
-breakage. Symptoms observed on the device:
-
-- `/etc/resolv.conf` correctly points at `100.100.100.100` (the manager works),
-- but `dig anything @100.100.100.100` from inside the container **times out**
-  ("no servers could be reached"),
-- and even tailnet-internal names fail: `ping host.<tailnet>.ts.net` →
-  `bad address` (a name that needs **no** upstream forwarding still can't
-  resolve, proving the listener itself is dead, not an upstream-resolver issue),
-- while `ping 1.1.1.1` (a raw IP needing no DNS) works fine over the kernel data
-  path — confirming forwarding/exit-node connectivity is unaffected and isolating
-  the fault to DNS serving.
-
-**It also fixed a crash.** Omitting `netstack` set `buildfeatures.HasNetstack`
-to a compile-time `false`, which turned the guard in
-`net/tstun.invertGSOChecksum` (`if !HasNetstack { panic("unreachable") }`) into
-an always-panic. That function is called on the packet-injection path used when
-enabling exit-node mode, producing `panic: unreachable` and a daemon restart
-loop. Enabling `netstack` makes `HasNetstack` a const `true`, so the guard
-becomes dead code and the crash disappears as a side effect — fixed at the root
-cause rather than patched around.
-
-**Cost.** Measured on arm64, a netstack-enabled build versus a netstack-omitted
-one:
-
-| Metric | netstack omitted | netstack enabled | Delta |
-|---|---|---|---|
-| Extracted rootfs (flash) | ~3.42 MB | ~3.91 MB | **+0.49 MB** |
-| `tailscale.combined` on disk (UPX) | ~2.99 MB | ~3.47 MB | +0.48 MB |
-| Resident RAM after UPX decompress | ~12.25 MB | ~14.56 MB | **+2.31 MB** |
-
-The flash cost (~0.5 MB) is negligible on a 16 MB-class device. The RAM cost
-(~2.3 MB resident) is the real consideration on low-memory models, but is
-acceptable given that without it MagicDNS is entirely non-functional. The
-trade is: **half a megabyte of flash to make MagicDNS work at all.** `gro`
-(Generic Receive Offload) depends on `netstack` and is pulled in alongside it;
-it is small and improves throughput on the netstack path.
-
-**Caveat for future Tailscale bumps.** This coupling (quad-100 serving living
-only in netstack) is an upstream implementation detail, not a stable contract.
-If a future release adds a genuine non-netstack quad-100 path — or the daemon
-itself is refactored — re-test whether `netstack` can be dropped again. The
-canary is simple: from inside the container, `dig google.com @100.100.100.100`
-must return answers and `ping <host>.<tailnet>.ts.net` must resolve.
-
-### Why peerapiserver is required for exit-node DNS
-
-This is a second non-obvious DNS inclusion, and it exposes a limitation of the
-allowlist build strategy.
-
-**Symptom.** With `netstack` enabled, MagicDNS worked from the router and from
-LAN hosts, including public names. But a device using this router **as its exit
-node** could not resolve public names: `dig google.com @100.100.100.100` on the
-*client* returned an instant authoritative `SERVFAIL` (`flags: qr aa rd ad`,
-`Query time: 0 msec`, "recursion not available"). Tailnet names and raw-IP
-connectivity (e.g. `ping 1.1.1.1`) through the exit node worked.
-
-**Root cause.** The `SERVFAIL` is generated **on the client**, locally, with no
-network I/O — which is why it is instant and authoritative. The path
-(traced through v1.98.5 source):
-
-1. The client's query for `google.com` reaches its in-process resolver, which
-   determines the name is not a tailnet name and marks it for forwarding
-   (`net/dns/resolver/tsdns.go`).
-2. The forwarder looks up which upstream resolver to use for the catch-all
-   `"."` route (`net/dns/resolver/forwarder.go` → `resolvers()`).
-3. That route set is **empty**, so `forwardWithDestChan` short-circuits and
-   synthesises an authoritative `SERVFAIL` (`servfailResponse`, `aa=1`) without
-   opening any socket. The query never reaches this router at all.
-
-Why the route set is empty: when a client selects an exit node,
-`dnsConfigForNetmap` (`ipn/ipnlocal/node_backend.go`) deliberately routes **all**
-default DNS through the exit node and drops the client's own LAN/system
-resolver — the whole premise of an exit node is "send everything, including
-DNS, through me." It does this by setting the client's default resolver to the
-exit node's **DoH proxy** URL (`http://<peer>/dns-query`). But that only happens
-if `exitNodeCanProxyDNS(thisRouter)` returns true — i.e. if **this router
-advertises a working PeerAPI DoH endpoint**. If it does not, and there is no
-tailnet global nameserver to fall back to, the client ends up with an empty
-default route and returns `SERVFAIL`.
-
-**Why this router didn't advertise the DoH proxy.** The `/dns-query` DoH
-endpoint is part of the **PeerAPI server**, gated by
-`buildfeatures.HasPeerAPIServer` (`ipn/ipnlocal/peerapi.go`). With
-`ts_omit_peerapiserver`, `initPeerAPIListenerLocked()` returns early: no PeerAPI
-listener is created, the `PeerAPIDNS` service is never advertised, and
-`peerCanProxyDNS()` is false for this node on every client.
-
-**The allowlist gap that caused it.** In `feature/featuretags/featuretags.go`,
-`advertiseexitnode` **declares a dependency on `peerapiserver`** ("to run the
-ExitDNS server"). Upstream's own `--add` resolution would have pulled it in.
-But this build's allowlist works differently: it runs `featuretags --min` to get
-the full omit set, then strips the specific `ts_omit_<feature>` tags it wants —
-it does **not** re-resolve transitive `Deps`. So opting in `advertiseexitnode`
-did not pull in `peerapiserver`, and `featuretags --min` had emitted
-`ts_omit_peerapiserver`, leaving the node an exit node *without* its declared
-ExitDNS dependency — a feature combination upstream's graph says shouldn't
-occur. Including `peerapiserver` explicitly closes the gap.
-
-> **Known limitation:** the allowlist (strip-individual-`ts_omit_`-tags) does
-> not resolve feature dependencies. When opting a feature in, check its `Deps`
-> in `featuretags.go` and add them explicitly. `peerapiserver` is the only such
-> gap found and fixed so far; a full dependency audit has not been done.
-
-**Cost.** Negligible. `peerapiserver` has **no** `Deps` and pulls in no large
-subsystems; measured at ~+10 kB on the UPX'd binary (arm64), rootfs unchanged
-within measurement noise.
-
-**Result.** The router now serves the exit-node DoH DNS proxy, so devices using
-it as their exit node resolve public names automatically — the normal exit-node
-behavior — with **no** tailnet DNS configuration required. (Setting a tailnet
-global nameserver in the admin console is an alternative runtime fix that also
-works, by populating the client's default resolver directly; it is not required
-once the router serves the proxy.)
-
-**Canary for future bumps:** from a client using this router as exit node,
-`dig google.com @100.100.100.100` must return real answers with `flags: ... ra`
-(recursion available) and a non-zero query time.
-
-### Log verbosity filtering
-
-Upstream `tailscaled` embeds verbosity tags (`[v1]`, `[v2]`, …) inside its log
-messages and relies on the **logtail** subsystem to act on them: in a stock
-build, logtail's log policy intercepts everything written via the standard
-`log` package, parses the tag, and only writes a line to stderr when its level
-is within `--verbose` (default 0 — non-verbose messages only). The `--verbose`
-flag is literally wired into logtail (`pol.SetVerbosityLevel(args.verbose)` in
-`cmd/tailscaled/tailscaled.go`).
-
-This build omits logtail (`ts_omit_logtail`) to avoid log-upload code and
-flash writes — but that removed the stderr filtering along with it, as
-collateral damage. The result: every verbose line went **unfiltered** to
-stderr and into the RouterOS container log, with the literal `[v1]` tag still
-in the text. On an active node that means constant spam, several lines per
-minute:
-
-```
-tailscale: ... [v1] Accept: TCP{...:53256 > ...:50000} 391 tcp non-syn
-tailscale: ... netcheck: [v1] report: udp=true v6=true ... derp=22 ...
-tailscale: ... wg: [v2] [0GwzF] - Receiving keepalive packet
-```
-
-This is a [known](https://github.com/tailscale/tailscale/issues/12158)
-[long-standing](https://github.com/tailscale/tailscale/issues/1548) complaint
-even in full builds, and RouterOS logging offers no way to discard matching
-messages (no drop action, rules are all-match — a regex rule duplicates rather
-than diverts).
-
-The fix here: the build injects a ~20-line Go file
-(`patches/stderr_verbosity_filter.go`, copied into `cmd/tailscaled/` before
-`go build`) whose `init()` wraps the standard log output and silently drops
-any line carrying a `[v1]`/`[v2]`/`[v3]` tag. This restores the exact
-equivalent of logtail's default `StderrLevel=0` behavior without pulling in
-the upload machinery. Properties:
-
-- **No upstream sources modified** — it's a new file in the package, so it
-  survives Tailscale version bumps without rebasing (only relies on the
-  daemon using the stdlib `log` package, which is core behavior).
-- **Build-tagged `//go:build ts_omit_logtail`** — if logtail is ever
-  re-enabled, the file compiles out automatically and logtail's own filtering
-  takes over; the two can never conflict.
-- **Runtime escape hatch** — setting the `TS_LOG_VERBOSITY=1` environment
-  variable disables the filter (and, conveniently, the same knob is read by
-  upstream as the default `--verbose` level). Verbose logs are one
-  `/container/envs/add` away; no rebuild needed. See
-  [USAGE.md → Logging](USAGE.md#logging).
-
 ## Volume layout
 
 Two mount points, with different persistence requirements:
@@ -451,22 +246,6 @@ Only the small, rarely-written state file touches flash; the socket dir is
 tmpfs. The netmap is held in memory only — see
 [Why netmap disk-caching is removed](#why-netmap-disk-caching-is-removed).
 
-### What lives in the state dir
-
-| File | Purpose | Write frequency |
-|---|---|---|
-| `tailscaled.state` | Node identity, auth keys, prefs | On auth / key rotation / prefs change |
-| `derpmap.cached.json` | Cached DERP relay server list for **bootstrap DNS**: at cold start with broken/unavailable DNS, tailscaled asks DERP servers to resolve the control plane. The binary ships a static DERP list, but it goes stale; this cache keeps the current one. | Once at first auth, then **only when Tailscale's relay infrastructure changes** (a few times a year). `dnsfallback.UpdateCache` has a deep-equal guard and skips the write when the DERP map is unchanged — netmap churn never touches it. |
-
-`derpmap.cached.json` is intentionally **kept** despite the flash-wear policy:
-the policy targets *frequent* writes (netmap deltas, logs), not one-shot
-caches. On a router this cache is genuinely useful — after a power outage the
-device may boot with WAN up but upstream DNS broken, exactly the case where a
-fresh DERP list lets the node reach the control plane anyway. With
-`cachenetmap` omitted, this file and `tailscaled.state` are the only cold-start
-resilience the node has. (There is no `ts_omit_*` tag for it; it is written
-only because `--statedir` is set.)
-
 ## Flash wear protection
 
 Several measures are in place to avoid wearing out internal flash:

docs/USAGE.md

@@ -9,7 +9,7 @@ reasoning behind these choices, see [DESIGN.md](DESIGN.md).
 
 ## Deploy on MikroTik (RouterOS)
 
-Verified on RouterOS 7.23 (arm64, CRS418). Commands are grouped into
+Verified on RouterOS 7.21.2 (arm64, CRS418). Commands are grouped into
 copy-paste blocks, defaults should fit most configurations.
 
 > Because the image has no built-in updater (the `clientupdate` feature is
@@ -19,9 +19,7 @@ copy-paste blocks, defaults should fit most configurations.
 
 ### 0. Prerequisites
 
-- RouterOS >= 7.23 with the **container** package installed
-  (7.23 is needed for container `restart-policy`; the deploy itself works on
-  >= 7.13 if you drop the restart options).
+- RouterOS >7.13 with the **container** package installed.
 - Container mode enabled ([documentation](https://manual.mikrotik.com/docs/System%20Information%20and%20Utilities/device-mode/#changing-mode-of-device-mode)):
 
   ```
@@ -82,8 +80,6 @@ just that directory:
     mountlists=tailscale_state \
     logging=yes \
     start-on-boot=yes \
-    restart-policy=on-failure \
-    restart-interval=10s \
     name=tailscale
 ```
 
@@ -181,40 +177,6 @@ When this is configured, you can connect to other tailscale machines using
 `[device name].[tailnet name].ts.net`. You can see and change assigned
 Tailnet DNS name in Tailscale admin panel under DNS tab.
 
-## Logging
-
-The container logs to the RouterOS log (topic `container`) via `logging=yes`.
-
-Upstream `tailscaled` is notoriously chatty: by default it would emit a line
-for every accepted connection (`Accept: TCP{...}`), every netcheck report, and
-every WireGuard handshake/keepalive — several lines per minute on an active
-node ([tailscale#12158](https://github.com/tailscale/tailscale/issues/12158)).
-This image filters those verbose (`[v1]`/`[v2]`-tagged) messages out at the
-source, so only meaningful messages (startup, auth, route changes, warnings,
-errors) reach the RouterOS log. See
-[DESIGN.md → Log verbosity filtering](DESIGN.md#log-verbosity-filtering) for
-how and why.
-
-To temporarily get the verbose logs back for debugging (e.g. NAT-traversal
-issues), set the `TS_LOG_VERBOSITY` environment variable and recreate the
-container with the envlist attached:
-
-```
-/container/envs/add list=tailscale_envs name=TS_LOG_VERBOSITY value=1
-/container/set [find where name=tailscale] envlist=tailscale_envs
-/container/stop [find where name=tailscale]
-/container/start [find where name=tailscale]
-```
-
-Any value ≥ 1 disables the filter (and raises the daemon's own verbosity by
-the same amount). Remove the variable and restart to silence it again:
-
-```
-/container/envs/remove [find where name=TS_LOG_VERBOSITY]
-/container/stop [find where name=tailscale]
-/container/start [find where name=tailscale]
-```
-
 ## Updating
 
 You don't normally do anything: when a new release is published, the

patches/stderr_verbosity_filter.go

@@ -1,45 +0,0 @@
-// Copyright (c) mikrotik-tailscale build. Injected at image build time.
-// SPDX-License-Identifier: BSD-3-Clause
-
-//go:build ts_omit_logtail
-
-package main
-
-// When logtail is compiled out (ts_omit_logtail), logpolicy is never
-// installed (see run() in tailscaled.go: `if buildfeatures.HasLogTail`),
-// so log.Printf output goes raw to stderr. Nothing parses the [v1]/[v2]
-// verbosity tags Tailscale embeds in log messages, which means every
-// verbose line (filter "Accept: TCP", "netcheck: [v1] report",
-// "wg: [v2]" handshakes/keepalives) is printed regardless of --verbose.
-//
-// This restores the equivalent of logtail's StderrLevel=0 behavior:
-// drop lines carrying a [v1]+ tag, unless TS_LOG_VERBOSITY is set to
-// 1 or higher (runtime escape hatch for debugging — no rebuild needed).
-
-import (
-	"bytes"
-	"log"
-	"os"
-)
-
-var verboseLogTags = [][]byte{[]byte("[v1] "), []byte("[v2] "), []byte("[v3] ")}
-
-type stderrVerbosityFilter struct{ w *os.File }
-
-func (f stderrVerbosityFilter) Write(p []byte) (int, error) {
-	for _, tag := range verboseLogTags {
-		if bytes.Contains(p, tag) {
-			// Claim success so the log package doesn't complain;
-			// the line is intentionally discarded.
-			return len(p), nil
-		}
-	}
-	return f.w.Write(p)
-}
-
-func init() {
-	if v := os.Getenv("TS_LOG_VERBOSITY"); v != "" && v != "0" {
-		return
-	}
-	log.SetOutput(stderrVerbosityFilter{os.Stderr})
-}

routeros/update-tailscale.rsc

@@ -3,9 +3,8 @@
 # =============================================================================
 # Checks the Gitea registry for a new :stable image and, only if the published
 # image actually changed, recreates the container. Designed for RouterOS 7.x
-# (tested target: 7.23, arm64). Requires RouterOS >= 7.23 for the container
-# restart-policy properties (and >= 7.13 for the :deserialize command used to
-# parse the registry token JSON).
+# (tested target: 7.21.2, arm64). Requires RouterOS >= 7.13 for the :deserialize
+# command used to parse the registry token JSON.
 #
 # HOW IT DECIDES "something changed":
 #   It fetches the manifest digest of the :stable tag from the registry and
@@ -60,12 +59,6 @@
 :local cInterface "veth-tailscale"
 :local cLogging   yes
 :local cStartOnBoot yes
-# Restart the container automatically if tailscaled crashes (tailscaled is
-# PID 1; if it dies the container stops). on-failure restarts only on abnormal
-# exit (a manual /container/stop stays stopped); 10s is a gentle backoff.
-# Requires RouterOS >= 7.23.
-:local cRestartPolicy "on-failure"
-:local cRestartInterval "10s"
 # ----------------------------------------------------------------------------
 
 :log info "$scriptName: checking for image updates"
@@ -181,8 +174,6 @@
     mountlists=$cMountList \
     logging=$cLogging \
     start-on-boot=$cStartOnBoot \
-    restart-policy=$cRestartPolicy \
-    restart-interval=$cRestartInterval \
     name=$cName
 } do={
   :log error "$scriptName: container add failed: $e"