Brad FitzpatrickandBrad Fitzpatrick 9107354488 tstest/natlab/vnet: send unsolicited IPv6 Router Advertisements
vnet only ever sent IPv6 RAs in response to a Router Solicitation. In
practice this meant gokrazy VMs running with a dual-stack LAN never
installed vnet's IPv6 default route: gokrazy brings the link up via
DHCPv4 and the kernel never emits an RS on its own under that init
path. Off-link IPv6 destinations like the fake DERP servers were
therefore unreachable from any gokrazy test node that also had v4
on the same interface. (Pure-v6 nodes happened to work because the
kernel sends an RS as part of v6-only autoconf.)

Fix this in two complementary ways:

  - Send an unsolicited RA every 5s to the link-local all-nodes group
    on every v6-enabled network. This matches what real routers do
    (RFC 4861 §6.2.1, MaxRtrAdvInterval; we use a much shorter
    interval than the spec's 200s default so short-lived tests don't
    have to wait).

  - Send a unicast RA to a newly-registered MAC as soon as a client
    first transmits on the wire. Without this the first periodic RA
    can land before any VM has connected and the next one isn't
    until the next tick, which can be longer than the test runs.

Factor the RA serialization out into buildIPv6RouterAdvertisement so
the solicited, periodic, and per-client paths all share one body.

Update TestSelfSignedDERPHashPinning to use a dual-stack hard-NAT
builder and assert zero errors from DebugDERPRegion (instead of
filtering "over IPv6" errors as it had to before this change). The
new builder also sets TS_DEBUG_STRIP_ENDPOINTS=1 on tailscaled so
disco can't find a direct path: without endpoint stripping, the now-
working non-NATted IPv6 LAN gives the two hard-NAT'd nodes a direct
route, defeating the test's "must traverse DERP" assertion. (Hard
NAT alone was enough before this change because v6 routing was
broken.) Also update sendBetweenClients in the vnet unit tests to
tolerate the new on-register RA noise on its read path.

Updates #13038
Updates #19973

Change-Id: Ic281dc53702a25fa773c46313f453837814233e8
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2026-06-02 12:59:27 -07:00
2026-06-01 12:09:49 -07:00
2026-01-27 16:15:17 -08:00
2026-06-02 10:59:29 -07:00

Tailscale

https://tailscale.com

Private WireGuard® networks made easy

Overview

This repository contains the majority of Tailscale's open source code. Notably, it includes the tailscaled daemon and the tailscale CLI tool. The tailscaled daemon runs on Linux, Windows, macOS, and to varying degrees on FreeBSD and OpenBSD. The Tailscale iOS and Android apps use this repo's code, but this repo doesn't contain the mobile GUI code.

Other Tailscale repos of note:

For background on which parts of Tailscale are open source and why, see https://tailscale.com/opensource/.

Using

We serve packages for a variety of distros and platforms at https://pkgs.tailscale.com.

Other clients

The macOS, iOS, and Windows clients use the code in this repository but additionally include small GUI wrappers. The GUI wrappers on non-open source platforms are themselves not open source.

Building

We always require the latest Go release, currently Go 1.26. (While we build releases with our Go fork, its use is not required.)

go install tailscale.com/cmd/tailscale{,d}

If you're packaging Tailscale for distribution, use build_dist.sh instead, to burn commit IDs and version info into the binaries:

./build_dist.sh tailscale.com/cmd/tailscale
./build_dist.sh tailscale.com/cmd/tailscaled

If your distro has conventions that preclude the use of build_dist.sh, please do the equivalent of what it does in your distro's way, so that bug reports contain useful version information.

Bugs

Please file any issues about this code or the hosted service on the issue tracker.

Contributing

PRs welcome! But please file bugs. Commit messages should reference bugs.

We require Developer Certificate of Origin Signed-off-by lines in commits.

See commit-messages.md (or skim git log) for our commit message style.

About Us

Tailscale is primarily developed by the people at https://github.com/orgs/tailscale/people. For other contributors, see:

WireGuard is a registered trademark of Jason A. Donenfeld.

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