tailscale/util/linuxfw/iptables_runner.go, branch awly/deadcode-linuxfwtest

util/linuxfw,wgengine/router: allow incoming CGNAT range traffic with nodeattr

2026-04-14T20:45:06Z

Clients with the newly added node attribute `"disable-linux-cgnat-drop-rule"` will not automatically drop inbound traffic on non-Tailscale network interfaces with the source IP in the CGNAT IP range. This is an initial proof-of-concept for enabling connectivity with off-Tailnet CGNAT endpoints. Fixes tailscale/corp#36270. Signed-off-by: Naman Sood

util/linuxfw: fix nil pointer panic in connmark rules without IPv6 (#18946)

2026-03-10T19:19:15Z

When IPv6 is unavailable on a system, AddConnmarkSaveRule() and DelConnmarkSaveRule() would panic with a nil pointer dereference. Both methods directly iterated over []iptablesInterface{i.ipt4, i.ipt6} without checking if ipt6 was nil. Use `getTables()` instead to properly retrieve the available tables on a given system Fixes #3310 Signed-off-by: Mike O'Driscoll

util/linuxfw,wgengine/router: add connmark rules for rp_filter workaround (#18860)

2026-03-04T19:09:11Z

When a Linux system acts as an exit node or subnet router with strict reverse path filtering (rp_filter=1), reply packets may be dropped because they fail the RPF check. Reply packets arrive on the WAN interface but the routing table indicates they should have arrived on the Tailscale interface, causing the kernel to drop them. This adds firewall rules in the mangle table to save outbound packet marks to conntrack and restore them on reply packets before the routing decision. When reply packets have their marks restored, the kernel uses the correct routing table (based on the mark) and the packets pass the rp_filter check. Implementation adds two rules per address family (IPv4/IPv6): - mangle/OUTPUT: Save packet marks to conntrack for NEW connections with non-zero marks in the Tailscale fwmark range (0xff0000) - mangle/PREROUTING: Restore marks from conntrack to packets for ESTABLISHED,RELATED connections before routing decision and rp_filter check The workaround is automatically enabled when UseConnmarkForRPFilter is set in the router configuration, which happens when subnet routes are advertised on Linux systems. Both iptables and nftables implementations are provided, with automatic backend detection. Fixes #3310 Fixes #14409 Fixes #12022 Fixes #15815 Fixes #9612 Signed-off-by: Mike O'Driscoll

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

tsconst, util/linuxfw, wgengine/router: move Linux fw consts to tsconst

2025-09-28T15:02:50Z

Now cmd/derper doesn't depend on iptables, nftables, and netlink code :) But this is really just a cleanup step I noticed on the way to making tsnet applications able to not link all the OS router code which they don't use. Updates #17313 Change-Id: Ic7b4e04e3a9639fd198e9dbeb0f7bae22a4a47a9 Signed-off-by: Brad Fitzpatrick

util/linuxfw, feature/buildfeatures: add ts_omit_iptables to make IPTables optional

2025-09-27T18:39:15Z

Updates #12614 Change-Id: Ic0eba982aa8468a55c63e1b763345f032a55b4e2 Signed-off-by: Brad Fitzpatrick

all: detect JetKVM and specialize a handful of things for it

2025-07-10T22:07:19Z

Updates #16524 Change-Id: I183428de8c65d7155d82979d2d33f031c22e3331 Signed-off-by: Brad Fitzpatrick

cmd/containerboot,util/linuxfw: create a SNAT rule for dst/src only once, clean up if needed (#13658)

2024-10-03T19:15:00Z

The AddSNATRuleForDst rule was adding a new rule each time it was called including: - if a rule already existed - if a rule matching the destination, but with different desired source already existed This was causing issues especially for the in-progress egress HA proxies work, where the rules are now refreshed more frequently, so more redundant rules were being created. This change: - only creates the rule if it doesn't already exist - if a rule for the same dst, but different source is found, delete it - also ensures that egress proxies refresh firewall rules if the node's tailnet IP changes Updates tailscale/tailscale#13406 Signed-off-by: Irbe Krumina

cmd/containerboot,kube,util/linuxfw: configure kube egress proxies to route to 1+ tailnet targets (#13531)

2024-09-29T15:30:53Z

* cmd/containerboot,kube,util/linuxfw: configure kube egress proxies to route to 1+ tailnet targets This commit is first part of the work to allow running multiple replicas of the Kubernetes operator egress proxies per tailnet service + to allow exposing multiple tailnet services via each proxy replica. This expands the existing iptables/nftables-based proxy configuration mechanism. A proxy can now be configured to route to one or more tailnet targets via a (mounted) config file that, for each tailnet target, specifies: - the target's tailnet IP or FQDN - mappings of container ports to which cluster workloads will send traffic to tailnet target ports where the traffic should be forwarded. Example configfile contents: { "some-svc": {"tailnetTarget":{"fqdn":"foo.tailnetxyz.ts.net","ports"{"tcp:4006:80":{"protocol":"tcp","matchPort":4006,"targetPort":80},"tcp:4007:443":{"protocol":"tcp","matchPort":4007,"targetPort":443}}}} } A proxy that is configured with this config file will configure firewall rules to route cluster traffic to the tailnet targets. It will then watch the config file for updates as well as monitor relevant netmap updates and reconfigure firewall as needed. This adds a bunch of new iptables/nftables functionality to make it easier to dynamically update the firewall rules without needing to restart the proxy Pod as well as to make it easier to debug/understand the rules: - for iptables, each portmapping is a DNAT rule with a comment pointing at the 'service',i.e: -A PREROUTING ! -i tailscale0 -p tcp -m tcp --dport 4006 -m comment --comment "some-svc:tcp:4006 -> tcp:80" -j DNAT --to-destination 100.64.1.18:80 Additionally there is a SNAT rule for each tailnet target, to mask the source address. - for nftables, a separate prerouting chain is created for each tailnet target and all the portmapping rules are placed in that chain. This makes it easier to look up rules and delete services when no longer needed. (nftables allows hooking a custom chain to a prerouting hook, so no extra work is needed to ensure that the rules in the service chains are evaluated). The next steps will be to get the Kubernetes Operator to generate the configfile and ensure it is mounted to the relevant proxy nodes. Updates tailscale/tailscale#13406 Signed-off-by: Irbe Krumina

util/linuxfw: don't try cleaning iptables on gokrazy

2024-05-30T04:02:45Z

It just generates log spam. Updates #12277 Change-Id: I5f65c0859e86de0a5349f9d26c9805e7c26b9371 Signed-off-by: Brad Fitzpatrick