Every netmap change, including an incremental delta of a single peer,
rebuilt the full MagicDNS state twice: dnsConfigForNetmap walked all
peers to build the dns.Config.Hosts map, and resolver.SetConfig then
walked that map again to build its reverse (PTR) index. On a tailnet
with 10k peers that is a lot of garbage per delta.
Instead, add a resolver.MagicDNSHosts hook, installed once by
LocalBackend, that the quad-100 resolver consults on demand at query
time. It is backed by nodeBackend's nodeByName, nodeByAddr, and peers
indexes, which are already maintained incrementally as netmap deltas
arrive. The subdomain-resolve capability check also moves to the hook
(checking the node's CapMap at query time), so dns.Config's
SubdomainHosts is no longer populated.
dns.Config.Hosts remains for control's DNS.ExtraRecords, which are
few and which feed the split-DNS decisions in dns.Manager's
compileConfig, and on Windows it still carries every node's records
because the hosts-file fallback path (compileHostEntries) needs the
complete enumerable set. Those compileConfig decisions also consulted
the per-node Hosts entries (hasHostsWithoutSplitDNSRoutes), so a new
Config.MagicDNSHostsUnrouted bit preserves that signal now that node
records are not listed: with MagicDNS names present but MagicDNS
domain routing off, quad-100 stays in the OS resolver path.
One small behavior change: reverse (PTR) lookups now also answer for
node addresses whose forward records are filtered out by the
IPv6-suppression rule (issue #1152), since nodeByAddr indexes all node
addresses. Previously such addresses were absent from the pushed
Hosts map and thus from the reverse index.
Updates #12542
Updates tailscale/corp#43949
Change-Id: I63b99199c2b3b124c08cb8bbaea1f63165095294
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
For dns.controld.com premium resolvers we synthesized per-resolver IPv6
addresses by encoding the resolver ID into the 2606:1a40::/48 range, but
those are legacy plaintext-DNS (port 53) endpoints that refuse TCP :443.
DoH now dials Control D's shared anycast IPs (the resolver ID stays in the
URL path), fixing SERVFAIL on IPv6-only/NAT64 networks where the v4
anycast fallback isn't reachable.
Fixes#20430
Signed-off-by: Brendan Creane <bcreane@gmail.com>
AddReportHistoryForTest temporarily swapped out Client.TimeNow without
holding any lock, racing with concurrent GetReport calls reading it
from ReSTUN goroutines during tests. Instead, pass the current time to
addReportHistoryAndSetPreferredDERP explicitly so the test helper never
needs to touch the field.
Fixes#20438
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Change-Id: I9c4f0a2f9427b5f1d3e8b06a49f0d2b71c3ee8a4
Give nodeBackend a RouteManager and keep it in sync as routing
inputs change: full netmaps resync the whole peer set (removals plus
no-op-cheap upserts), incremental netmap deltas mirror their peer
upserts and removes into the same mutation batch, and
authReconfigLocked pushes the routing-relevant prefs (exit node,
subnet route acceptance, OneCGNAT) after resolving the exit node's
stable ID to its current numeric node ID.
A selected exit node that doesn't resolve to a current peer (a
nonexistent node, or MDM's "auto:any" placeholder awaiting
resolution) is not the same as no exit node: per the long-standing
ipn.Prefs.ExitNodeID contract, it blackholes internet traffic rather
than letting it escape to the local network. RouteManager's Prefs
gains an ExitNodeSelected bit so its OS route set keeps the default
routes in that case, with no outbound peer to carry them, matching
what routerConfigLocked does today, as pinned by TestRouterConfigExitNodeBlackhole in the previous commit.
All mutations happen with nodeBackend.mu held, satisfying the
RouteManager's serialized Begin/Commit contract.
Nothing consumes its snapshots yet; the wgengine data plane and OS
router wiring come next.
Updates #12542
Change-Id: I677b6b2c9efb8e41b3d27071bd9db73e01640d3b
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Add a new RouteManager type that tracks per-peer self addresses and
advertised routes and incrementally maintains two read-only
snapshots: an IP-to-outbound-peer bart table carrying the per-peer
attributes the data plane needs (jailed state, masquerade addresses),
and a coarsened OS route set (including OneCGNAT consolidation).
Mutations are staged in a transaction (Begin/Commit) and applied to
the snapshots via bart's Persist methods, which path-copy only the
few trie nodes along the affected prefix, so a single-peer delta
costs a bounded amount of work independent of the number of peers,
instead of the O(n) full-world rebuild done today. Snapshots are
published via atomic pointer swap for lock-free reads on the hot
path, and Commit reports which peers' allowed IPs changed so callers
can sync wireguard-go incrementally. This is the same immutable value
snapshot pattern as used in the recent containerboot change,
364b952d62.
Nothing uses it yet; this is pulled out of a future change that wires
it into ipnlocal and wgengine, to make that PR smaller.
Updates #12542
Change-Id: Iccc5258024e6f90311835b79fd2d83b2adb0d09d
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Due to a customer issue, I investigated the Windows Dnscache service more
intensively. I learned that the only time it attempts to read the NRPT
from group policy is in response to a group policy change notification.
Under the hypothesis that policy refresh is not effectively delivering GP
notifications due to its dependency on reaching a DC, I replaced our use
of the RefreshPolicyEx with the quasi-documented GenerateGPNotification API.
Tests have been updated to ensure they check that they are running as
LocalSystem, which is required for GenerateGPNotification.
Fixes#20187
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
Found with the regex `\b([A-Za-z]+) \1\b`.
Updates #cleanup
Change-Id: I4cc51784d9b6437d3d0c66b531828707f87f7fd5
Signed-off-by: Alex Chan <alexc@tailscale.com>
Now that the routecheck subsystem is continuously collecting
reachability reports in the background, we can add a hook to
LocalBackend for fetching its report. That allows
suggestExitNodeUsingTrafficSteering to consult that report when
disqualifying candidates, instead of blocking on an immediate probe.
Exit node suggestions will only consult the report when the
`client-side-reachability` and `client-side-reachability-routecheck`
node attributes are both set on the current node.
Updates #17366
Updates tailscale/corp#33033
Signed-off-by: Simon Law <sfllaw@tailscale.com>
Previously, refreshing the routecheck.Client would probe to generate a
new routecheck.Report, but this method was only wired up to the
LocalAPI and the `tailscale routecheck` command. However, waiting for
a probe to finish before choosing a router would take too long, so we
must keep a regularly updated report to be consulted as necessary.
This patch adds a Start and Close method to the routecheck.Client and
starts it in the background from features/routecheck. To enable this
feature for a given node, set both of the following node attributes:
`client-side-reachability` and `client-side-reachability-routecheck`.
This patch also wires up the RouterTracker.OnRoutersChange hook, which
fires a callback whenever a new network map includes information about
a router node, This signals to the routecheck.Client that it might
need to schedule another probe, if the shape of the routing table has
changed materially.
Updates #17366
Updates tailscale/corp#33033
Signed-off-by: Simon Law <sfllaw@tailscale.com>
This patch adds a new ipnext.NotifyWatcher interface that exposes
ipn.LocalBackend.WatchNotifications so that extensions inside
tailscaled can subscribe to the IPN bus, much like how the GUI
clients subscribe to it through the Local API.
This interface is used by the new feature/routecheck.RouterTracker to
watch for changes in the peer map that affect routers. RouterTracker
uses dead reckoning to incrementally maintain the set of routers. We
do this to avoid looping over the peer map repeatedly. See #17366.
RouterTracker supports two hooks:
- OnNetMapAvailable signals that the initial netmap has been received,
so that the routecheck.Client can wake up goroutines that are
waiting for it.
- OnRoutersChange signals that the set of routers has changed, so that
the routecheck.Client can decide to probe a subset of the routers
instead of all of them. Currently, this optimization hasn’t been
implemented yet.
Updates #17366
Updates #20062
Updates tailscale/corp#33033
Co-authored-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Signed-off-by: Simon Law <sfllaw@tailscale.com>
Cache the OS split-DNS capability while compiling DNS config and return directly for split-capable platforms that do not need the Apple base-config workaround.
This removes the base-config sentinel pointer and keeps the iOS and sandboxed macOS fallback path explicit.
Updates #1338
Change-Id: I836417c8fa775b35d3be9bc80cf6841d30cec222
Signed-off-by: Maisem Ali <maisem@bold.dev>
The macOS tailscaled DNS configurator only wrote /etc/resolver files, which can express split DNS but not a primary resolver. Teach it to configure a global resolver through the SystemConfiguration dynamic store using scutil when OSConfig has nameservers and no match domains.
Let non-sandboxed macOS tailscaled follow Linux split DNS behavior when its OS configurator reports split DNS support. This avoids synthesizing an upstream default route from the machine's base DNS when the netmap did not provide one. Keep iOS and sandboxed macOS app builds on the existing Apple base-config path because those use NetworkExtension DNS settings rather than tailscaled's /etc/resolver configurator.
Add tests for switching between split and global DNS, including cleanup of stale Tailscale-managed resolver files, removal of the dynamic-store global DNS key, and preservation of the sandboxed macOS behavior.
RELNOTE: tailscaled on macOS now supports configuring global DNS resolvers.
Updates #1338
Change-Id: I9b2b61f89750a5529fc0add1cd37b1b9a355db12
Signed-off-by: Maisem Ali <maisem@bold.dev>
This adds the NotifyInitialPolicy watch option and the Policy field in
Notify so that clients can receive the effective policy snapshot via IPN
bus.
This extends policyclient.Client so ipnlocal can get and watch policy
snapshots, which is used by sysPolicyChanged to notify watchers.
User-scoped policy store registration, management, and cleanup will be
added in a follow-up
Updates tailscale/corp#42259
Signed-off-by: kari <kari@tailscale.com>
This patch adds a new `client-side-reachability-routecheck` node
attribute to allow admins to selectively enable background routecheck
probing on trial nodes. The current implementation is still
experimental.
It adds the routecheck.IsEnabled helper to check for the new
`client-side-reachability-routecheck` node attribute alongside the
existing `client-side-reachability` node attribute in this node’s self
capabilities. This allows administrators to turn on and off this
feature by editing the policy file.
It adds the `TS_DEBUG_FORCE_CLIENT_SIDE_REACHABILITY_ROUTECHECK`
environment variable which can be set to override the policy file.
When set to `true`, it forcibly enables this feature. And when set to
`false`, it forcibly disables it.
Updates #17366
Updates tailscale/corp#33033
Signed-off-by: Simon Law <sfllaw@tailscale.com>
The primary purpose is that return packets from the target app get
properly SNATed on connectors with --tun=userspace-networking, matching
the NAT behavior in the kernel tun path.
This is also necessary but not sufficient for clients of connectors in
userspace networking mode. The hook will DNAT MagicIPs, but won't
actually be sent MagicIPs until conn25 app connector DNS works with
userspace networking.
Fixestailscale/corp#43201
Signed-off-by: Michael Ben-Ami <mzb@tailscale.com>
tsdial.Dialer.SetNetMap rebuilt an O(n peers) map of MagicDNS names on
every netmap change. As we move toward per-peer incremental deltas,
this becomes quadratic. This removes it and replaces it with
SetResolveMagicDNS, a callback into LocalBackend that looks up
hostnames from nodeBackend's new nodeByName index (populated alongside
nodeByAddr/nodeByKey on both full and delta paths). The index stores
both FQDNs and short names as keys.
This is the same treatment applied to netlog (8f210454d), wglog
(988b0905b), and drive (1d6989408): stop pushing *netmap.NetworkMap
into subsystems and instead have them pull from LocalBackend's live
data via callbacks.
Updates #12542
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Change-Id: I24557ab0c8a27636e08e4779bcfd3ec633db0a78
Outbound packets produced by netstack (used by tailscaled with
--tun userspace-networking, by tsnet, and by the SOCKS5/HTTP proxies)
enter the wrapper via InjectOutbound{,PacketBuffer} and take the
injectedRead path, which bypasses Filter.RunOut.
RunOut's side effect for UDP/SCTP is to insert the reverse-flow tuple
into the connection-tracking LRU so that Filter.RunIn admits inbound
replies that no explicit ACL rule covers. Skipping it on the injected
path meant a netstack-side dial of UDP would send fine but the reply
would be dropped as "no matching rule". The kernel-TUN path was
already fine because it goes through RunOut.
Fixes#14229Fixes#20064
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Change-Id: I816ef55c493a12ff4f561cd89c095559b5c2743b
suggestExitNodeLocked now ranks exit node candidates using the per-region
latency tracked by the netcheck Client (RecentRegionLatency), which merges
the reports retained in c.prev. That history is only useful for far-away
regions if it contains a full netcheck report, since incremental reports
only re-probe the home region and a handful of the fastest ones.
The full-report cadence in GetReport and the c.prev retention window were
two independent 5-min constants - the way we schedule netchecks ensured
that the history always contaned a full report, but it was not a strong
contract and we did not have any checks around this.
Now full report interval and retention window are driven by the same
var, and a test confirms that the history contains a full report.
Updates tailscale/corp#17516
Signed-off-by: Anton Tolchanov <anton@tailscale.com>
When recommending an exit node, suggestExitNodeLocked ranks candidates by
the latency to their home DERP region, taken from the most recent netcheck
report. But netcheck alternates between full reports, which probe every
region, and incremental reports, which only re-probe the home region and a
handful of the fastest regions. When the most recent report is incremental,
the suggestion fell back to a random for exit nodes that are far away.
Now we rank candidates against the best recent latency, tracked by the
`netcheck.Client` - the same data that is used to pick the preferred
DERP. It uses a history of measurements which includes a full netcheck
report, so should cover all DERP regions.
Updates tailscale/corp#17516
Signed-off-by: Anton Tolchanov <anton@tailscale.com>
In direct mode we write resolv.conf via a temp file and rename(2), which
preserves the source's generic etc_t label instead of net_conf_t, causing
AVC denials when NetworkManager later manages the file. Run restorecon
after the rename (Linux, SELinux-enforcing, best effort) to restore the
policy-default label.
Fixes#20149
Signed-off-by: Brendan Creane <bcreane@gmail.com>
Add support for configuring egress to destinations reachable via 4via6
subnet routes, using either the synthesized 4via6 address or the MagicDNS
name (in the form <IPv4-with-hyphens>-via-<siteID>[.*]).
Also update the Connector to validate and advertise 4via6 subnet routes.
Export net/netutil.ValidateViaPrefix so it can be reused by the Connector
validation logic.
This change only affects standalone egress proxies — ProxyGroup egress
requires IPv6 support before it can use 4via6.
Updates #19334
Change-Id: I6faecd6eb61ab55fc0cd97fe417af6b6a12fe7fc
Signed-off-by: Becky Pauley <becky@tailscale.com>
Mappings from transit IPs to real IPs are stored ephemerally in the
connector, so they're lost on restart. When we send a packet to the
connector with a transit IP it does not recognize, it sends us a TSMP
message saying so (see #19883). If we (the client) know of such a
mapping, we now re-send it to the connector so that a connection can
proceed.
Fixestailscale/corp#34256.
Signed-off-by: Naman Sood <mail@nsood.in>
Follow-up cleanups to the IPv6 fragment extension header support added in
the previous commit:
- Document that minFragBlks is sized for IPv4 but intentionally reused by
decode6 for IPv6 fragments, where it is conservative (IPv6 fragments
carry no per-fragment IP header) and only ever rejects more later
fragments as Unknown, never fewer.
- Add a TestDecode case for a first fragment reachable only through a
chained extension header (base Next Header = Hop-by-Hop Options, which
chains to Fragment). decode6 only parses the Fragment header when it is
the base header's immediate Next Header, so this must classify as
Unknown. The test locks in that scoping decision.
Updates #20083
Updates #20140
Change-Id: Ibece03c6baf2385b0cc399f179819b08cbe921cc
Signed-off-by: James Tucker <james@tailscale.com>
decode6 didn't parse the IPv6 Fragment extension header (Next Header 44),
so any source-fragmented IPv6 packet was classified as an unknown protocol
and matched no ACL rule. The filter then silently dropped it and counted it
as an "acl" drop, even on allow-all tailnets, blackholing large UDP (DNS,
WebRTC, etc.) over a tailnet's IPv6 addresses. IPv4 fragments were already
handled by decode4.
Parse the fragment header the same way: read the first fragment's transport
ports so the filter matches it like an unfragmented packet, pass later
fragments through as ipproto.Fragment, and reject overlapping-fragment
offsets (RFC 1858) and first fragments too short to hold the transport
header as unknown.
Fixes#20083
Signed-off-by: Steve Avery <hello@stevenavery.com>
This removes deprecated magic-dns formats for 4via6 subnet routers.
These are superseded by the current format: Q-R-S-T-via-X.
Fixes#20053
Change-Id: I0eed1f057f856f248c4dc8ce3b751f6c7edcfbfd
Signed-off-by: Becky Pauley <becky@tailscale.com>
macOS 26.4 emits RTM_MISS on the routing socket for every failed route
lookup. skipRouteMessage never inspected the message type, so each miss
woke the monitor as a link change and triggered a netcheck. On networks
without an IPv6 default route the netcheck's IPv6 DERP probes fail and
emit more RTM_MISS messages, sustaining the loop indefinitely: netchecks
run at roughly 40x the intended rate, with sustained probe traffic and
corresponding CPU and battery cost.
RTM_MISS scales with traffic volume, not network state, and is never
the leading signal for a topology change: route withdrawals emit
RTM_DELETE synchronously before any subsequent lookup can miss, so
ignoring it loses no signal. Other routing daemons (bird, dhcpcd, frr)
ignore it as well.
Same fix as coder/tailscale@e956a95074.
Fixes#19324
Signed-off-by: Doug Bryant <dougbryant@anthropic.com>
When MagicDNS is enabled but no global upstream resolvers are configured,
the forwarder only handles specific suffixes and defers other names to the
system resolver. A query it has no resolver for is expected in that case, so
don't raise the dns-forward-failing warning unless a default "." route makes
Tailscale the default resolver.
Fixes#19931
Signed-off-by: Brendan Creane <bcreane@gmail.com>
Commit 2b338dd6a8 removed watchdogEngine because it was weird
(so many methods) and increasingly unnecessary after we'd cleaned up
and simplified so much of the locking.
This adds back a watchdog, but an easier to maintain one that's more
idiomatic.
Updates #19759
Change-Id: I86c458473e126c0809f37696446ce7acf4cc4eb9
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Several packages built their HTTP transports with
http.DefaultTransport.(*http.Transport).Clone()
The standard library only documents http.DefaultTransport as an
http.RoundTripper, so an application is free to replace it with a
RoundTripper that is not a *http.Transport (e.g. an instrumented or
tracing wrapper). When such an application embeds tsnet.Server, the
unchecked type assertion panics as soon as tsnet brings up its control
connection, DNS bootstrap, or log uploader.
Add netutil.NewDefaultTransport, which returns a clone of the global
when it is still the standard *http.Transport (preserving existing
behavior) and otherwise returns a fresh transport mirroring the stdlib
defaults. Route every clone site through it.
Updates #19937
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Signed-off-by: Achille Roussel <achille.roussel@gmail.com>
Introduce a new `tailscale routecheck` command which prints a report
of high-availability routers that are reachable.
This command rhymes with the `tailscale netcheck` command and but
instead of reporting on local network conditions, `routecheck` reports
on remote connectivity.
Updates #17366
Updates tailscale/corp#33033
Signed-off-by: Simon Law <sfllaw@tailscale.com>
When a connector receives a packet from a client on a transit IP that it
can't find a real IP mapping for, it drops the packet. This commit
starts notifying the client of this dropping over TSMP, so the client
can tell the connector to re-establish the transit IP-real IP binding.
Updates tailscale/corp#34256.
Signed-off-by: Naman Sood <mail@nsood.in>
In order to support a `tailscale routecheck` command, we introduce the
`/localapi/v0/routecheck` endpoint to the local API. This endpoint
returns the most recent report collected by the routecheck client.
If `force=true` is an argument in the query string, then this endpoint
will actively probe before returning the report.
Updates #17366
Updates tailscale/corp#33033
Signed-off-by: Simon Law <sfllaw@tailscale.com>
The routecheck package parallels the netcheck package, where the
former checks routes and routers while the latter checks networks.
Like netcheck, it compiles reports for other systems to consume.
Historically, the client has never known whether a peer is actually
reachable. Most of the time this doesn’t matter, since the client will
want to establish a WireGuard tunnel to any given destination.
However, if the client needs to choose between two or more nodes,
then it should try to choose a node that it can reach.
Suggested exit nodes are one such example, where the client filters
out any nodes that aren’t connected to the control plane. Sometimes an
exit node will get disconnected from the control plane: when the
network between the two is unreliable or when the exit node is too
busy to keep its control connection alive. In these cases, Control
disables the Node.Online flag for the exit node and broadcasts this
across the tailnet. Arguably, the client should never have relied on
this flag, since it only makes sense in the admin console.
This patch implements an initial routecheck client that can probe
every node that your client knows about. You should not ping scan your
visible tailnet, this method is for debugging only.
This patch also introduces a new OnNetMapToggle hook, which fires when
the netmap transitions from nil to non-nil, or vice versa. This
happens either when the client receives its first MapResponse after
connecting to the control plane, or when it clears the netmap while it
is disconnecting. Routecheck uses this to wait for a valid netmap
so it knows which peers to probe.
Updates #17366
Updates tailscale/corp#33033
Signed-off-by: Simon Law <sfllaw@tailscale.com>
In case we land on this branch during a goto retry. Also, protect
Geneve offset from mutation across retries.
Fixes#19927
Signed-off-by: Jordan Whited <jordan@tailscale.com>
In PR #19682, we introduced the traffic package which provides a
traffic.Scores.SortNodes method that uses rendezvous hashing to
break ties by equally distribute the “best” node for any given client.
This PR adds a fuzzer to make sure this algorithm is not wildly unfair.
Updates #17366
Updates tailscale/corp#33033
Signed-off-by: Simon Law <sfllaw@tailscale.com>
This NodeCapability works around the UDP GSO bugs introduced by
torvalds/linux@b10b446 (v7.0-rc1). These bugs were later fixed by
torvalds/linux@78effd8 and torvalds/linux@5f17ae0 (v7.1-rc5). These
Linux kernel bugs cause mangled UDP headers and UDP checksums, resulting
in high levels of packet loss.
The aforementioned bugs have already made their way downstream into
various distros, e.g. Ubuntu 26.04 LTS. Impacted users are now dealing
with poor UDP performance in tailscaled, and in any other software that
makes use of UDP GSO.
Not all users of the affected kernels are impacted as the relevant
kernel code path sits between kernel and netdev driver, and behaviors
vary by driver/device capability.
We cannot detect impact at runtime, as this would require gathering all
netdevs, and performing loopback tests. This is invasive and in many
cases impossible.
So, we are left to choose between disabling UDP GSO for all users on
affected kernels, whether they experience real impact or not, or try
and work around the bugs. Disabling UDP GSO for a user that is not
impacted can cut max throughput in half, and consume more CPU cycles.
This commit attempts to workaround the bugs by avoiding UDP GSO when
batches are small, and injecting a 1-byte sentinel tail payload when
they are large. This tail payload is smaller than "GSO size", which
sidesteps the primary trigger of all fragments in a batch being
equal in length.
The end result is slightly increased payload and packet overhead, but
functional UDP GSO for all Linux 7.0-7.1.4 users, regardless of
netdev/driver.
Updates #19777
Signed-off-by: Jordan Whited <jordan@tailscale.com>
Add four control-plane node attributes that let us disable UDP GSO/GRO
on the magicsock UDP socket and UDP/TCP GRO on the Tailscale TUN
device.
These complement the pre-existing TS_DEBUG_DISABLE_UDP_{GRO,GSO} and
TS_TUN_DISABLE_{UDP,TCP}_GRO envknobs. They exist so we can mitigate
upstream Linux kernel regressions on a deployed fleet without
requiring a client release, after two incidents (#13041, #19777) where
buggy kernel patches landed upstream and the fix took an excessively
long time to reach downstream distros.
Knob changes are reacted to in setNetworkMapInternal / SetNetworkMap via
a comparison against a cached "last applied" value and only an actual
transition triggers work: magicsock Rebind()+ReSTUN for UDP,
ApplyGROKnobs for TUN. The TUN side is gated by buildfeatures.HasGRO and
is one-way (wireguard-go GRO disablement is sticky); re-enabling
requires a client restart.
Updates #13041
Updates #19777
Change-Id: I802993070afa659cc06809bb0bfbb7f8a0cdb273
Signed-off-by: James Tucker <james@tailscale.com>
bind() on NETLINK_ROUTE sockets does not work on Android 11+ (https://developer.android.com/identity/user-data-ids#mac-11-plus) . Since system/bin/ip uses bind(), likelyHomeRouterIPHelper() always fails on Andoroid 11+, so that GatewayAndSelfIP never caches the result, causing repeated ip process spawns on every periodic ReSTUN.
This replaces the system/bin/ip fallback with a cached gateway IP pushed from Android’s ConnectivityManager via LinkProperties.getRoutes(). This is the same patterm used by UpdateLastKnownDefaultRouteInterface for the interface name (see https://github.com/tailscale/tailscale/pull/11784/). We keep the proc/net/route path as a fallback for early startup before NetworkChangeCallback has fired.
Updates tailscale/tailscale#18622
Updates tailscale/tailscale#13352
Signed-off-by: kari-ts <kari@tailscale.com>
It is sometimes useful when diagnosing subtle and specific performance
problems to rule out GRO/GSO independently and/or toggle them to
influence packet pacing.
Updates #17835
Updates tailscale/corp#31164
Signed-off-by: James Tucker <james@tailscale.com>
Add support for configuring egress to destinations reachable via 4via6
subnet routes. This change affects standalone egress proxy only- egress
ProxyGroup needs IPv6 support before being able to support 4via6. Egress may
be configured using either the synthesized 4via6 address or the MagicDNS
name (in the form
<IPv4-address-with-hyphens-instead-of-dots>-via-<siteid>[.*]).
Also update the Connector to validate and advertise 4via6 subnet routes.
Export net/netutil.ValidateViaPrefix so it can be reused by the Connector
validation logic.
Updates #19334
Signed-off-by: Becky Pauley <becky@tailscale.com>
In PR tailscale/corp#30448, we originally decided to break ties using
SHA256 for our rendezvous hashing algorithm. Now that we’ve had some
experience with it, we think that FNV-1a is a better choice. It
distributes bits evenly, it’s much faster, and it doesn’t need to be
cryptographically secure. The FNV designers recommend FNV-1a over the
deprecated FNV-1.
This PR makes the switch and updates the related tests, since changing
the algorithm changes which stable pick gets selected. As of 2026-05,
this is the best time to make this change, since there are almost no
clients in the wild with traffic steering enabled.
Updates #17366
Updates tailscale/corp#29964
Updates tailscale/corp#29966
Updates tailscale/corp#33033
Signed-off-by: Simon Law <sfllaw@tailscale.com>
The traffic package contains helpers for evaluating traffic steering
scores and picking appropriate nodes. These were extracted from
ipnlocal.suggestExitNodeUsingTrafficSteering so they can be reused by
the new routecheck package to probe exit nodes in priority order.
Updates #17366
Updates tailscale/corp#33033
Signed-off-by: Simon Law <sfllaw@tailscale.com>
When tailscaled is running in userspace-networking mode behind an
exit node (e.g. as a SOCKS5 proxy), it resolves a hostname and then
dials a single resolved IP through the tunnel. If the name has both
A and AAAA, Go's net.Resolver merges them and we pick ips[0], which
on an IPv6-native host is usually AAAA. If the exit node has no IPv6
egress (or vice versa), the dial fails silently through the tunnel
and the user sees a hang.
Resolve all candidates and race connect attempts across address
families with a 300ms happy-eyeballs delay, matching Go's net.Dialer
default and the existing pattern in net/dnscache (commit ee0a03b14).
First success wins; losers are cancelled and any conns they produce
are closed. A failBoost channel wakes the launcher when a connect
fails fast (e.g. ICMP "no route" via the tunnel) so we don't sit on
the 300ms timer when the answer is already known.
userDialResolve is refactored into userDialResolveAll (returns the
full candidate list) plus a thin single-IP wrapper for callers like
UserDialPlan that don't race. UserDial's per-IP dispatch (netstack
vs peer dialer vs SystemDial vs std) is extracted to dialOneUser so
each candidate can route correctly on its own merits.
Also fix serveDial in localapi to pass the original hostname to
UserDial rather than a pre-resolved IP, so the race can fire.
This fix is single-ended: it works against any exit node, including
old ones, with no protocol changes. The trade-off versus filtering
on the exit-node side via PeerAPI DoH is that every dial through an
unreachable-family exit node costs one failed connect attempt per
cache window, rather than zero, which is acceptable given the
simplicity.
Fixes#19792Fixes#13257
Change-Id: I9d7645d0034caf3ee22ecdd8070798353f77e94b
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
