libtailscale #

A headless Tailscale / Headscale node for Dart and Flutter, embedded in your process through dart:ffi bindings to the official libtailscale C library.

The host application supplies a control-server URL and a credential; the library joins the tailnet and exposes just enough to control the node and operate over it. It renders nothing, opens no browser and has no platform channels.

import 'package:libtailscale/libtailscale.dart';

final node = TailscaleNode(TailscaleConfig(
  controlUrl: Uri.parse('https://headscale.example.com'), // omit for Tailscale
  credential: const TailscaleCredential.authKey('tskey-auth-…'),
  hostname: 'inventory-agent',
  stateDir: '/path/to/writable/state',
  ephemeral: true,
));

await node.start();
await node.waitUntilRunning(timeout: const Duration(seconds: 60));
print(node.addresses.ipv4);                    // 100.x.y.z

final server = await node.listen(port: 8080);  // Stream<TailscaleSocket>
server.listen((c) => c.addStream(c));          // echo service on the tailnet

final socket = await node.connect('files', 443);      // dart:io Socket via SOCKS5
final http = node.httpClient();                        // HttpClient over the tailnet
final peers = (await node.status()).peers;             // name, IPs, online, tags, OS

node.stateChanges.listen((s) => print('tailscale: $s'));
await node.close();

Scope #

Anything else in tailscaled's LocalAPI stays reachable through node.localApi.raw(...), without compatibility guarantees.

Credentials #

Headscale #

Point controlUrl at the Headscale base URL; nothing else changes. Headscale has no OAuth client API (use pre-auth keys), issues no TLS certificates (status.certDomains is empty) and does not support Funnel or Serve. enableFunnelToLocalhost refuses to run without a certificate domain because the underlying C call would crash the process.

An unreachable or wrong control URL produces no error from tsnet; the node just stays in Starting/NeedsLogin. waitUntilRunning therefore always takes a timeout and reports the last state and health messages in the exception.

Sockets and TLS #

• connect() returns a Socks5Socket, a real dart:io Socket tunnelled through the node's loopback SOCKS5 proxy. Because the SOCKS handshake consumes the raw stream, use socket.secure(...) (or node.connectSecure) for TLS instead of SecureSocket.secure.
• httpClient() sets connectionFactory so package:http's IOClient, dio, gRPC and WebSocket.connect(customClient:) work unchanged. Pass a SecurityContext / bad-certificate callback to httpClient() itself.
• listen() and dial() use libtailscale's file-descriptor path and yield TailscaleSocket (a Stream<Uint8List> + IOSink). Dart cannot wrap a foreign fd in a Socket, so TLS is not available on that path.

Everything that can block runs on helper isolates (Isolate.run); a dedicated isolate drives all fds with a single poll(2) loop.

Build configuration #

The package ships no binaries in the pub archive. hook/build.dart provides the native library at build time, in this order:

1. prebuilt_dir: a directory containing libtailscale.{dylib,so} (or the architecture-specific libtailscale-<os>-<arch>[-<sdk>].<ext>).
2. build_from_source: go build -buildmode=c-shared from a pinned upstream checkout (any installed Go; the NDK/Xcode toolchains for mobile). The hook sets GOTOOLCHAIN=go1.25.5+auto so go downloads and uses the exact version upstream builds with, because newer Go releases break tailscale's pinned dependencies; set go_toolchain: local to use the installed one. iOS is built as a c-archive and linked into a dylib because Go has no c-shared mode for GOOS=ios.
3. Download of the prebuilt library from this repository's native release, verified against the SHA-256 pinned in lib/src/hook/native_manifest.dart.

With no configuration the hook takes option 3 and downloads the library for the pinned release. To build from source or use a local copy instead, configure it in the application's pubspec.yaml:

hooks:
  user_defines:
    libtailscale:
      build_from_source: true
      # prebuilt_dir: native/libs
      # source_dir: ../libtailscale
      # go: /usr/local/go/bin/go

Hooks run with a filtered environment, so environment variables cannot configure the build. While developing this package itself, a git-ignored hook/local_config.json takes the same keys and overrides the pubspec values:

{"build_from_source": true, "build_test_control": true}

The file is only read when the root package names it with the local_config user-define, which this package's own pubspec.yaml does. Applications, including the examples in this repository, never inherit it and configure the hook in their own pubspec as shown above.

Android #

Minimum API 35. The library is linked with 16 KB page alignment and a soname. Add the INTERNET permission to your manifest.

Two Android-only accommodations are built in. Apps may not use netlink RTM_GETLINK since Android 11, which breaks Go's net.Interfaces() inside tsnet; the hook therefore compiles lib/src/hook/android_interfaces.go into the library (through go build -overlay, the upstream tree stays untouched), registering a getifaddrs(3)-based interface getter with tailscale's netmon. And because an app process has no $HOME or $TMPDIR, which makes tsnet's log policy panic, start() sets both to the state directory when missing, in the C environment and, through a helper exported by that same Go file, in the Go runtime's copy of it.

iOS #

Minimum iOS 15. Flutter wraps the dylib in tailscale.framework (it drops the lib prefix). Userspace WireGuard stops while the app is suspended; upstream reports the loopback listener can become stale afterwards, in which case the node falls back to tailscale_status_json for status and dial() keeps working. Set NSLocalNetworkUsageDescription (peers on the same LAN are reached directly) and ship a privacy manifest; the one in examples/node_console/ios/Runner declares the file-timestamp and system-boot-time API categories the Go runtime and tsnet use.

Flutter versions #

The hook depends on package:hooks and package:code_assets with ranges that include the versions pinned by the current Flutter stable (hooks 1.0.x, code_assets 1.0.x) as well as the 2.x releases used with a plain Dart SDK.

Linux #

Built on Ubuntu 24.04; requires glibc ≥ 2.39.

Examples #

• example/example.dart: the whole API in one short program: join with an auth key, print node and peers, echo service, dial a peer.
• examples/tsnode/: tsnode, a headless command-line node built on the public API: join, info, peers, echo, send and fetch. Its README shows how to try it against Tailscale, Headscale, or the in-process test control server without any account.
• examples/node_console/: a Flutter app for macOS, iOS, Android and Linux with three screens (Connect, Node, Communicate) on top of one controller; chat and HTTP fetch interoperate with tsnode. See its README for the device checklist and the platform settings (entitlements, permissions, privacy manifest) an embedding app needs. Both directories under examples/ are repository-only; the pub archive ships example/example.dart.

Development #

git submodule update --init                 # upstream sources (header, Go code)
dart test                                   # unit + libc/reactor tests, no Go needed
dart test -x native                         # pure Dart only
echo '{"build_from_source": true, "build_test_control": true}' > hook/local_config.json
LIBTAILSCALE_INTEGRATION=1 dart test -t integration          # hermetic e2e (Go)
(cd tool/ffigen && dart run bin/generate.dart)               # regenerate bindings
dart run tool/build_native.dart --os macos --arch arm64 --out build/native

The package's own pubspec.yaml sets allow_missing_native: true so the pure-Dart tests run on machines without Go or network access. That setting only applies when the package is the root package.

Cutting a native release #

1. Bump the submodule if upstream moved and update upstreamCommit, upstreamTailscaleVersion and minimumGoVersion in lib/src/hook/native_manifest.dart; run the hermetic tests.

2. Start the Native release workflow (Actions tab, input native-vX.Y.Z, or push that tag). It builds the ten libraries in NativeTarget.releaseTargets on macOS, Linux x64/arm64 and Android runners, publishes them with SHA256SUMS as a GitHub release, downloads every asset back to verify it, and opens a pull request that pins the digests in lib/src/hook/native_manifest.dart (tool/update_manifest.dart). Opening the pull request needs "Allow GitHub Actions to create and approve pull requests" in the repository's Actions settings (and, for an organization, in the organization's). Without it the step fails softly and the native-manifest/native-vX.Y.Z branch is still pushed: open the pull request by hand, or pin the checksums locally:

   gh release download native-vX.Y.Z --pattern SHA256SUMS
   dart run tool/update_manifest.dart --sums SHA256SUMS --tag native-vX.Y.Z
   

3. Merge that pull request, bump version: in pubspec.yaml, update the changelog and push a vX.Y.Z tag; publish.yml publishes to pub.flutter-io.cn.

dart run tool/update_manifest.dart --sums SHA256SUMS --tag native-vX.Y.Z --check verifies a checkout against a release's checksum file.

Repository layout #

Known limitations #

• tailscale_up is never used: it blocks and cannot be cancelled. waitUntilRunning implements the same condition in Dart.
• tailscale_close does not close listeners or connections; the node tracks and closes every fd itself before calling it.
• UDP is not exposed in this version (the fd path loses datagram boundaries; SOCKS5 UDP ASSOCIATE is planned).
• One pipe write end is intentionally leaked per node started with captureLogs: true, because Go owns that fd number.

License #

BSD-3-Clause, like libtailscale itself.