tailscale/wgengine/netstack/netstack_test.go, branch main

wgengine/netstack: absorb all quad-100 traffic locally, never leak to peers

2026-04-24T19:42:16Z

Previously, handleLocalPackets intercepted traffic to the Tailscale service IP (100.100.100.100 / fd7a:115c:a1e0::53) only for an allow-list of ports: TCP 53/80/8080 and UDP 53. Any other port returned filter.Accept, letting the packet fall through to the ACL filter and wireguard-go, which would attempt a peer lookup. No peer owns the quad-100 AllowedIP, so after ~5s pendopen.go would log: open-conn-track: timeout opening ...; no associated peer node This is the common "conntrack error no peer found for 100.100.100.100:853" log spam seen in the wild (e.g. from systemd-resolved or another resolver speculatively trying DoT on quad-100). It also leaks quad-100 packets onto the tailnet. Remove the port allow-list so handleLocalPackets absorbs every quad-100 packet into netstack regardless of IP protocol or port. Traffic never reaches the conntrack / peer-routing layers. With the allow-list gone, acceptTCP needs a corresponding guard: on a quad-100 TCP port we don't serve, execution used to fall through to the isTailscaleIP case (quad-100 is in the tailscale IP range), which rewrote the dial target to 127.0.0.1: and forwardTCP'd the connection to whatever happened to be listening on the host's loopback at that port. Add a hittingServiceIP case that RSTs cleanly instead, placed before the isTailscaleIP fallthrough. TestQuad100UnservedTCPPortDoesNotForward is a new integration test that injects a TCP SYN to 100.100.100.100:853 via handleLocalPackets, stubs forwardDialFunc, and asserts the dialer is not invoked; it catches regressions of the acceptTCP recursion/loopback-redirection case. Fixes #15796 Fixes #19421 Updates #3261 Updates #11305 Signed-off-by: James Tucker

all: fix six tests that failed with -count=2

2026-04-14T01:52:57Z

Avery found a bunch of tests that fail with -count=2. Updates tailscale/corp#40176 (tracks making our CI detect them) Change-Id: Ie3e4398070dd92e4fe0146badddf1254749cca20 Signed-off-by: Brad Fitzpatrick Co-authored-by: Avery Pennarun

wgengine/netstack: fix data race on in-flight connection test globals

2026-04-13T22:24:35Z

The maxInFlightConnectionAttemptsForTest and maxInFlightConnectionAttemptsPerClientForTest globals were plain ints read by background gVisor TCP handler goroutines (via wrapTCPProtocolHandler) and written by tstest.Replace cleanup in TestTCPForwardLimits_PerClient. When a gVisor goroutine outlived the test cleanup window, the race detector caught the unsynchronized access. The race-prone code was introduced in c5abbcd4b4d8 (2024-02-26, "wgengine/netstack: add a per-client limit for in-flight TCP forwards") which added both the plain int globals and the TestTCPForwardLimits_PerClient test that writes them via tstest.Replace. It is not obvious why this has only recently started being detected as a data race; likely some combination of gVisor version bumps, Go toolchain scheduler changes, and additional TCP-injecting subtests (e.g. 03461ea7f, 2026-01-30) increased goroutine churn enough to hit the window. Change both globals to atomic.Int32 and replace tstest.Replace (which does non-atomic *target = old on cleanup) with explicit Store/Cleanup pairs. Fixes #19118 Change-Id: Id26ba6fbfb2e4ade319976db80af8e16c7c8778e Signed-off-by: Brad Fitzpatrick

wgengine/netstack: allow UDP listeners to receive traffic on Service VIP addresses (#18972)

2026-04-08T09:53:50Z

Fixes UDP listeners on VIP Service addresses not receiving inbound traffic. - Modified shouldProcessInbound to check for registered UDP transport endpoints when processing packets to service VIPs - Uses FindTransportEndpoint to determine if a UDP listener exists for the destination VIP/port - Supports both IPv4 and IPv6 The aim was to mirror the existing TCP logic, providing feature parity for UDP-based services on VIP Services. Fixes #18971 Signed-off-by: chaosinthecrd

wgengine/netstack: deliver self-addressed packets via loopback

2026-02-27T22:30:41Z

When a tsnet.Server dials its own Tailscale IP, TCP SYN packets are silently dropped. In inject(), outbound packets with dst=self fail the shouldSendToHost check and fall through to WireGuard, which has no peer for the node's own address. Fix this by detecting self-addressed packets in inject() using isLocalIP and delivering them back into gVisor's network stack as inbound packets via a new DeliverLoopback method on linkEndpoint. The outbound packet must be re-serialized into a new PacketBuffer because outbound packets have their headers parsed into separate views, but DeliverNetworkPacket expects raw unparsed data. Updates #18829 Signed-off-by: James Tucker

wgengine/netstack: add local tailscale service IPs to route and terminate locally (#18461)

2026-01-30T21:46:03Z

* wgengine/netstack: add local tailscale service IPs to route and terminate locally This commit adds the tailscales service IPs served locally to OS routes, and make interception to packets so that the traffic terminates locally without making affects to the HA traffics. Fixes tailscale/corp#34048 Signed-off-by: KevinLiang10 <37811973+KevinLiang10@users.noreply.github.com> * fix test Signed-off-by: KevinLiang10 <37811973+KevinLiang10@users.noreply.github.com> * add ready field to avoid accessing lb before netstack starts Signed-off-by: KevinLiang10 <37811973+KevinLiang10@users.noreply.github.com> * wgengine/netstack: store values from lb to avoid acquiring a lock Signed-off-by: KevinLiang10 <37811973+KevinLiang10@users.noreply.github.com> * add active services to netstack on starts with stored prefs. Signed-off-by: KevinLiang10 <37811973+KevinLiang10@users.noreply.github.com> * fix comments Signed-off-by: KevinLiang10 <37811973+KevinLiang10@users.noreply.github.com> * update comments Signed-off-by: KevinLiang10 <37811973+KevinLiang10@users.noreply.github.com> --------- Signed-off-by: KevinLiang10 <37811973+KevinLiang10@users.noreply.github.com>

all: remove AUTHORS file and references to it

2026-01-23T23:49:45Z

This file was never truly necessary and has never actually been used in the history of Tailscale's open source releases. A Brief History of AUTHORS files --- The AUTHORS file was a pattern developed at Google, originally for Chromium, then adopted by Go and a bunch of other projects. The problem was that Chromium originally had a copyright line only recognizing Google as the copyright holder. Because Google (and most open source projects) do not require copyright assignemnt for contributions, each contributor maintains their copyright. Some large corporate contributors then tried to add their own name to the copyright line in the LICENSE file or in file headers. This quickly becomes unwieldy, and puts a tremendous burden on anyone building on top of Chromium, since the license requires that they keep all copyright lines intact. The compromise was to create an AUTHORS file that would list all of the copyright holders. The LICENSE file and source file headers would then include that list by reference, listing the copyright holder as "The Chromium Authors". This also become cumbersome to simply keep the file up to date with a high rate of new contributors. Plus it's not always obvious who the copyright holder is. Sometimes it is the individual making the contribution, but many times it may be their employer. There is no way for the proejct maintainer to know. Eventually, Google changed their policy to no longer recommend trying to keep the AUTHORS file up to date proactively, and instead to only add to it when requested: https://opensource.google/docs/releasing/authors. They are also clear that: > Adding contributors to the AUTHORS file is entirely within the > project's discretion and has no implications for copyright ownership. It was primarily added to appease a small number of large contributors that insisted that they be recognized as copyright holders (which was entirely their right to do). But it's not truly necessary, and not even the most accurate way of identifying contributors and/or copyright holders. In practice, we've never added anyone to our AUTHORS file. It only lists Tailscale, so it's not really serving any purpose. It also causes confusion because Tailscalars put the "Tailscale Inc & AUTHORS" header in other open source repos which don't actually have an AUTHORS file, so it's ambiguous what that means. Instead, we just acknowledge that the contributors to Tailscale (whoever they are) are copyright holders for their individual contributions. We also have the benefit of using the DCO (developercertificate.org) which provides some additional certification of their right to make the contribution. The source file changes were purely mechanical with: git ls-files | xargs sed -i -e 's/\(Tailscale Inc &\) AUTHORS/\1 contributors/g' Updates #cleanup Change-Id: Ia101a4a3005adb9118051b3416f5a64a4a45987d Signed-off-by: Will Norris

health,ipn/ipnlocal: introduce eventbus in heath.Tracker (#17085)

2025-09-16T15:25:29Z

The Tracker was using direct callbacks to ipnlocal. This PR moves those to be triggered via the eventbus. Additionally, the eventbus is now closed on exit from tailscaled explicitly, and health is now a SubSystem in tsd. Updates #15160 Signed-off-by: Claus Lensbøl

net/netmon: publish events to event bus

2025-04-16T17:10:45Z

Updates #15160 Signed-off-by: David Anderson

all: update the tsd.System constructor name (#15372)

2025-04-16T17:10:45Z

Replace NewSystemWithEventBus with plain NewSystem, and update all usage. See https://github.com/tailscale/tailscale/pull/15355#discussion_r2003910766 Updates #15160 Change-Id: I64d337f09576b41d9ad78eba301a74b9a9d6ebf4 Signed-off-by: M. J. Fromberger