Commit Graph

1026 Commits (3511d1f8a23938dea8ddb5183528eb78ec491d21)

Author SHA1 Message Date
Aaron Klotz 3511d1f8a2 cmd/tailscaled, net/dns, wgengine/router: start Windows child processes with DETACHED_PROCESS when I/O is being piped
When we're starting child processes on Windows that are CLI programs that
don't need to output to a console, we should pass in DETACHED_PROCESS as a
CreationFlag on SysProcAttr. This prevents the OS from even creating a console
for the child (and paying the associated time/space penalty for new conhost
processes). This is more efficient than letting the OS create the console
window and then subsequently trying to hide it, which we were doing at a few
callsites.

Fixes #12270

Signed-off-by: Aaron Klotz <aaron@tailscale.com>
6 months ago
Nick Khyl 4cdc4ed7db net/dns/resolver: return an empty successful response instead of NXDomain when resolving A records for 4via6 domains
As quad-100 is an authoritative server for 4via6 domains, it should always return responses
with a response code of 0 (indicating no error) when resolving records for these domains.
If there's no resource record of the specified type (e.g. A), it should return a response
with an empty answer section rather than NXDomain. Such a response indicates that there
is at least one RR of a different type (e.g., AAAA), suggesting the Windows stub resolver
to look for it.

Fixes tailscale/corp#20767

Signed-off-by: Nick Khyl <nickk@tailscale.com>
6 months ago
Irbe Krumina bc53ebd4a0
ipn/{ipnlocal,localapi},net/netkernelconf,client/tailscale,cmd/containerboot: optionally enable UDP GRO forwarding for containers (#12410)
Add a new TS_EXPERIMENTAL_ENABLE_FORWARDING_OPTIMIZATIONS env var
that can be set for tailscale/tailscale container running as
a subnet router or exit node to enable UDP GRO forwarding
for improved performance.
See https://tailscale.com/kb/1320/performance-best-practices#linux-optimizations-for-subnet-routers-and-exit-nodes
This is currently considered an experimental approach;
the configuration support is partially to allow further experimentation
with containerized environments to evaluate the performance
improvements.

Updates tailscale/tailscale#12295

Signed-off-by: Irbe Krumina <irbe@tailscale.com>
6 months ago
Brad Fitzpatrick 916c4db75b net/dns: fix crash in tests
Looks like #12346 as submitted with failing tests.

Updates #12346

Change-Id: I582cd0dfb117686330d935d763d972373c5ae598
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
6 months ago
Andrea Gottardo b65221999c
tailcfg,net/dns: add controlknob to disable battery split DNS on iOS (#12346)
Updates corp#15802.

Adds the ability for control to disable the recently added change that uses split DNS in more cases on iOS. This will allow us to disable the feature if it leads to regression in production. We plan to remove this knob once we've verified that the feature works properly.

Signed-off-by: Andrea Gottardo <andrea@gottardo.me>
6 months ago
Brad Fitzpatrick 1ca323ac65 net/netcheck: fix probeProto.String result for IPv6 probes
This bug was introduced in e6b84f215 (May 2020) but was only used in
tests when stringifying probeProto values on failure so it wasn't
noticed for a long time.

But then it was moved into non-test code in 8450a18aa (Jun 2024) and I
didn't notice during the code movement that it was wrong. It's still
only used in failure paths in logs, but having wrong/ambiguous
debugging information isn't the best.

Whoops.

Updates tailscale/corp#20654

Change-Id: I296c727ed1c292a04db7b46ecc05c07fc1abc774
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
6 months ago
Brad Fitzpatrick 8450a18aa9 net/netcheck: flesh out some logging in error paths
Updates tailscale/corp#20654

Change-Id: Ie190f956b864985668f79b5b986438bbe07ce905
6 months ago
Maisem Ali 4a8cb1d9f3 all: use math/rand/v2 more
Updates #11058

Signed-off-by: Maisem Ali <maisem@tailscale.com>
6 months ago
Andrea Gottardo d636407f14
net/dns: don't set MatchDomains on Apple platforms when no upstream nameservers available (#12334)
This PR addresses a DNS issue on macOS as discussed this morning.

Signed-off-by: Andrea Gottardo <andrea@gottardo.me>
6 months ago
Andrew Dunham ced9a0d413
net/dns: fix typo in OSConfig logging (#12330)
Updates tailscale/corp#20530

Change-Id: I48834a0a5944ed35509c63bdd2830aa34e1bddeb

Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
6 months ago
Maisem Ali 42cfbf427c tsnet,wgengine/netstack: add ListenPacket and tests
This adds a new ListenPacket function on tsnet.Server
which acts mostly like `net.ListenPacket`.

Unlike `Server.Listen`, this requires listening on a
specific IP and does not automatically listen on both
V4 and V6 addresses of the Server when the IP is unspecified.

To test this, it also adds UDP support to tsdial.Dialer.UserDial
and plumbs it through the localapi. Then an associated test
to make sure the UDP functionality works from both sides.

Updates #12182

Signed-off-by: Maisem Ali <maisem@tailscale.com>
6 months ago
Andrea Gottardo dd77111462
xcode/iOS: set MatchDomains when no route requires a custom DNS resolver (#10576)
Updates https://github.com/tailscale/corp/issues/15802.

On iOS exclusively, this PR adds logic to use a split DNS configuration in more cases, with the goal of improving battery life. Acting as the global DNS resolver on iOS should be avoided, as it leads to frequent wakes of IPNExtension.

We try to determine if we can have Tailscale only handle DNS queries for resources inside the tailnet, that is, all routes in the DNS configuration do not require a custom resolver (this is the case for app connectors, for instance).

If so, we set all Routes as MatchDomains. This enables a split DNS configuration which will help preserve battery life. Effectively, for the average Tailscale user who only relies on MagicDNS to resolve *.ts.net domains, this means that Tailscale DNS will only be used for those domains.

This PR doesn't affect users with Override Local DNS enabled. For these users, there should be no difference and Tailscale will continue acting as a global DNS resolver.

Signed-off-by: Andrea Gottardo <andrea@tailscale.com>
6 months ago
James Tucker 87ee559b6f net/netcheck: apply some polish suggested from #12161
Apply some post-submit code review suggestions.

Updates #12161
Updates tailscale/corp#19106

Signed-off-by: James Tucker <james@tailscale.com>
6 months ago
James Tucker 9351eec3e1 net/netcheck: remove hairpin probes
Palo Alto reported interpreting hairpin probes as LAND attacks, and the
firewalls may be responding to this by shutting down otherwise in use NAT sessions
prematurely. We don't currently make use of the outcome of the hairpin
probes, and they contribute to other user confusion with e.g. the
AirPort Extreme hairpin session workaround. We decided in response to
remove the whole probe feature as a result.

Updates #188
Updates tailscale/corp#19106
Updates tailscale/corp#19116

Signed-off-by: James Tucker <james@tailscale.com>
6 months ago
James Tucker 8d1249550a net/netcheck,wgengine/magicsock: add potential workaround for Palo Alto DIPP misbehavior
Palo Alto firewalls have a typically hard NAT, but also have a mode
called Persistent DIPP that is supposed to provide consistent port
mapping suitable for STUN resolution of public ports. Persistent DIPP
works initially on most Palo Alto firewalls, but some models/software
versions have a bug which this works around.

The bug symptom presents as follows:

- STUN sessions resolve a consistent public IP:port to start with
- Much later netchecks report the same IP:Port for a subset of
  sessions, most often the users active DERP, and/or the port related
  to sustained traffic.
- The broader set of DERPs in a full netcheck will now consistently
  observe a new IP:Port.
- After this point of observation, new inbound connections will only
  succeed to the new IP:Port observed, and existing/old sessions will
  only work to the old binding.

In this patch we now advertise the lowest latency global endpoint
discovered as we always have, but in addition any global endpoints that
are observed more than once in a single netcheck report. This should
provide viable endpoints for potential connection establishment across
a NAT with this behavior.

Updates tailscale/corp#19106

Signed-off-by: James Tucker <james@tailscale.com>
6 months ago
Kevin Liang 7f83f9fc83 Net/DNS/Publicdns: update the IPv6 range that we use to recreate route endpoint for control D
In this commit I updated the Ipv6 range we use to generate Control D DOH ip, we were using the NextDNSRanges to generate Control D DOH ip, updated to use the correct range.

Updates: #7946
Signed-off-by: Kevin Liang <kevinliang@tailscale.com>
6 months ago
Maisem Ali 1f51bb6891 net/tstun: do SNAT after filterPacketOutboundToWireGuard
In a configuration where the local node (ip1) has a different IP (ip2)
that it uses to communicate with a peer (ip3) we would do UDP flow
tracking on the `ip2->ip3` tuple. When we receive the response from
the peer `ip3->ip2` we would dnat it back to `ip3->ip1` which would
then not match the flow track state and the packet would get dropped.

To fix this, we should do flow tracking on the `ip1->ip3` tuple instead
of `ip2->ip3` which requires doing SNAT after the running filterPacketOutboundToWireGuard.

Updates tailscale/corp#19971, tailscale/corp#8020

Signed-off-by: Maisem Ali <maisem@tailscale.com>
7 months ago
Maisem Ali 85b9a6c601 net/netcheck: do not add derps if IPv4/IPv6 is set to "none"
It was documented as such but seems to have been dropped in a
refactor, restore the behavior. This brings down the time it
takes to run a single integration test by 2s which adds up
quite a bit.

Updates tailscale/corp#19786

Signed-off-by: Maisem Ali <maisem@tailscale.com>
7 months ago
Maisem Ali af97e7a793 tailcfg,all: add/plumb Node.IsJailed
This adds a new bool that can be sent down from control
to do jailing on the client side. Previously this would
only be done from control by modifying the packet filter
we sent down to clients. This would result in a lot of
additional work/CPU on control, we could instead just
do this on the client. This has always been a TODO which
we keep putting off, might as well do it now.

Updates tailscale/corp#19623

Signed-off-by: Maisem Ali <maisem@tailscale.com>
7 months ago
Maisem Ali e67069550b ipn/ipnlocal,net/tstun,wgengine: create and plumb jailed packet filter
This plumbs a packet filter for jailed nodes through to the
tstun.Wrapper; the filter for a jailed node is equivalent to a "shields
up" filter. Currently a no-op as there is no way for control to
tell the client whether a peer is jailed.

Updates tailscale/corp#19623

Co-authored-by: Andrew Dunham <andrew@du.nham.ca>
Signed-off-by: Maisem Ali <maisem@tailscale.com>
Change-Id: I5ccc5f00e197fde15dd567485b2a99d8254391ad
7 months ago
Nick Khyl f62e678df8 net/dns/resolver, control/controlknobs, tailcfg: use UserDial instead of SystemDial to dial DNS servers
Now that tsdial.Dialer.UserDial has been updated to honor the configured routes
and dial external network addresses without going through Tailscale, while also being
able to dial a node/subnet router on the tailnet, we can start using UserDial to forward
DNS requests. This is primarily needed for DNS over TCP when forwarding requests
to internal DNS servers, but we also update getKnownDoHClientForProvider to use it.

Updates tailscale/corp#18725

Signed-off-by: Nick Khyl <nickk@tailscale.com>
7 months ago
Maisem Ali 5ef178fdca net/tstun: refactor peerConfig to allow storing more details
This refactors the peerConfig struct to allow storing more
details about a peer and not just the masq addresses. To be
used in a follow up change.

As a side effect, this also makes the DNAT logic on the inbound
packet stricter. Previously it would only match against the packets
dst IP, not it also takes the src IP into consideration. The beahvior
is at parity with the SNAT case.

Updates tailscale/corp#19623

Co-authored-by: Andrew Dunham <andrew@du.nham.ca>
Signed-off-by: Maisem Ali <maisem@tailscale.com>
Change-Id: I5f40802bebbf0f055436eb8824e4511d0052772d
7 months ago
Nick Khyl caa3d7594f ipn/ipnlocal, net/tsdial: plumb routes into tsdial and use them in UserDial
We'd like to use tsdial.Dialer.UserDial instead of SystemDial for DNS over TCP.
This is primarily necessary to properly dial internal DNS servers accessible
over Tailscale and subnet routes. However, to avoid issues when switching
between Wi-Fi and cellular, we need to ensure that we don't retain connections
to any external addresses on the old interface. Therefore, we need to determine
which dialer to use internally based on the configured routes.

This plumbs routes and localRoutes from router.Config to tsdial.Dialer,
and updates UserDial to use either the peer dialer or the system dialer,
depending on the network address and the configured routes.

Updates tailscale/corp#18725
Fixes #4529

Signed-off-by: Nick Khyl <nickk@tailscale.com>
7 months ago
Brad Fitzpatrick ce8969d82b net/portmapper: add envknob to disable portmapper in localhost integration tests
Updates #11962

Change-Id: I8212cd814985b455d96986de0d4c45f119516cb3
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
7 months ago
Brad Fitzpatrick c3c18027c6 all: make more tests pass/skip in airplane mode
Updates tailscale/corp#19786

Change-Id: Iedc6730fe91c627b556bff5325bdbaf7bf79d8e6
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
7 months ago
Maisem Ali fd6ba43b97 types/views: remove duplicate SliceContainsFunc
We already have `(Slice[T]).ContainsFunc`.

Updates #cleanup

Signed-off-by: Maisem Ali <maisem@tailscale.com>
7 months ago
Brad Fitzpatrick e42c4396cf net/netcheck: don't spam on ICMP socket permission denied errors
While debugging a failing test in airplane mode on macOS, I noticed
netcheck logspam about ICMP socket creation permission denied errors.

Apparently macOS just can't do those, or at least not in airplane
mode. Not worth spamming about.

Updates #cleanup

Change-Id: I302620cfd3c8eabb25202d7eef040c01bd8a843c
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
7 months ago
Brad Fitzpatrick ee3bd4dbda derp/derphttp, net/netcheck: plumb netmon.Monitor to derp netcheck client
Fixes #11981

Change-Id: I0e15a09f93aefb3cfddbc12d463c1c08b83e09fd
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
7 months ago
Andrew Dunham f97d0ac994 net/dns/resolver: add better error wrapping
To aid in debugging exactly what's going wrong, instead of the
not-particularly-useful "dns udp query: context deadline exceeded" error
that we currently get.

Updates #3786
Updates #10768
Updates #11620
(etc.)

Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
Change-Id: I76334bf0681a8a2c72c90700f636c4174931432c
7 months ago
Andrew Dunham be663c84c1 net/tstun: rename natConfig to peerConfig
So that we can use this for additional, non-NAT configuration without it
being confusing.

Updates #cleanup

Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
Change-Id: I1658d59c9824217917a94ee76d2d08f0a682986f
7 months ago
Andrew Dunham 10497acc95 net/tstun: refactor natConfig to not be per-family
This was a holdover from the older, pre-BART days and is no longer
necessary.

Updates #cleanup

Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
Change-Id: I71b892bab1898077767b9ff51cef33d59c08faf8
7 months ago
Jonathan Nobels 45b9aa0d83
net/netmon: remove spammy log statements (#11953)
Updates tailscale/corp#18960

Tests in corp called us using the wrong logging calls.  Removed.
This is logged downstream anyway.

Signed-off-by: Jonathan Nobels <jonathan@tailscale.com>
7 months ago
Jonathan Nobels fa1303d632
net/netmon: swap to swift-derived defaultRoute on macos (#11936)
Updates tailscale/corp#18960

iOS uses Apple's NetworkMonitor to track the default interface and
there's no reason we shouldn't also use this on macOS, for the same
reasons noted in the comments for why this change was made on iOS.

This eliminates the need to load and parse the routing table when
querying the defaultRouter() in almost all cases.

A slight modification here (on both platforms) to fallback to the default
BSD logic in the unhappy-path rather than making assumptions that
may not hold.  If netmon is eventually parsing AF_ROUTE and able
to give a consistently correct answer for the  default interface index,
we can fall back to that and eliminate the Swift dependency.

Signed-off-by: Jonathan Nobels <jonathan@tailscale.com>
7 months ago
Jordan Whited a47ce618bd
net/tstun: implement env var for disabling UDP GRO on Linux (#11924)
Certain device drivers (e.g. vxlan, geneve) do not properly handle
coalesced UDP packets later in the stack, resulting in packet loss.

Updates #11026

Signed-off-by: Jordan Whited <jordan@tailscale.com>
7 months ago
Brad Fitzpatrick b9adbe2002 net/{interfaces,netmon}, all: merge net/interfaces package into net/netmon
In prep for most of the package funcs in net/interfaces to become
methods in a long-lived netmon.Monitor that can cache things.  (Many
of the funcs are very heavy to call regularly, whereas the long-lived
netmon.Monitor can subscribe to things from the OS and remember
answers to questions it's asked regularly later)

Updates tailscale/corp#10910
Updates tailscale/corp#18960
Updates #7967
Updates #3299

Change-Id: Ie4e8dedb70136af2d611b990b865a822cd1797e5
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
7 months ago
Brad Fitzpatrick 6b95219e3a net/netmon, add: add netmon.State type alias of interfaces.State
... in prep for merging the net/interfaces package into net/netmon.

This is a no-op change that updates a bunch of the API signatures ahead of
a future change to actually move things (and remove the type alias)

Updates tailscale/corp#10910
Updates tailscale/corp#18960
Updates #7967
Updates #3299

Change-Id: I477613388f09389214db0d77ccf24a65bff2199c
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
7 months ago
Brad Fitzpatrick 3672f29a4e net/netns, net/dns/resolver, etc: make netmon required in most places
The goal is to move more network state accessors to netmon.Monitor
where they can be cheaper/cached. But first (this change and others)
we need to make sure the one netmon.Monitor is plumbed everywhere.

Some notable bits:

* tsdial.NewDialer is added, taking a now-required netmon

* because a tsdial.Dialer always has a netmon, anything taking both
  a Dialer and a NetMon is now redundant; take only the Dialer and
  get the NetMon from that if/when needed.

* netmon.NewStatic is added, primarily for tests

Updates tailscale/corp#10910
Updates tailscale/corp#18960
Updates #7967
Updates #3299

Change-Id: I877f9cb87618c4eb037cee098241d18da9c01691
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
7 months ago
Brad Fitzpatrick 7a62dddeac net/netcheck, wgengine/magicsock: make netmon.Monitor required
This has been a TODO for ages. Time to do it.

The goal is to move more network state accessors to netmon.Monitor
where they can be cheaper/cached.

Updates tailscale/corp#10910
Updates tailscale/corp#18960
Updates #7967
Updates #3299

Change-Id: I60fc6508cd2d8d079260bda371fc08b6318bcaf1
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
7 months ago
Brad Fitzpatrick 4dece0c359 net/netutil: remove a use of deprecated interfaces.GetState
I'm working on moving all network state queries to be on
netmon.Monitor, removing old APIs.

Updates tailscale/corp#10910
Updates tailscale/corp#18960
Updates #7967
Updates #3299

Change-Id: If0de137e0e2e145520f69e258597fb89cf39a2a3
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
7 months ago
Brad Fitzpatrick 745931415c health, all: remove health.Global, finish plumbing health.Tracker
Updates #11874
Updates #4136

Change-Id: I414470f71d90be9889d44c3afd53956d9f26cd61
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
7 months ago
Brad Fitzpatrick 723c775dbb tsd, ipnlocal, etc: add tsd.System.HealthTracker, start some plumbing
This adds a health.Tracker to tsd.System, accessible via
a new tsd.System.HealthTracker method.

In the future, that new method will return a tsd.System-specific
HealthTracker, so multiple tsnet.Servers in the same process are
isolated. For now, though, it just always returns the temporary
health.Global value. That permits incremental plumbing over a number
of changes. When the second to last health.Global reference is gone,
then the tsd.System.HealthTracker implementation can return a private
Tracker.

The primary plumbing this does is adding it to LocalBackend and its
dozen and change health calls. A few misc other callers are also
plumbed. Subsequent changes will flesh out other parts of the tree
(magicsock, controlclient, etc).

Updates #11874
Updates #4136

Change-Id: Id51e73cfc8a39110425b6dc19d18b3975eac75ce
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
7 months ago
Brad Fitzpatrick 5b32264033 health: break Warnable into a global and per-Tracker value halves
Previously it was both metadata about the class of warnable item as
well as the value.

Now it's only metadata and the value is per-Tracker.

Updates #11874
Updates #4136

Change-Id: Ia1ed1b6c95d34bc5aae36cffdb04279e6ba77015
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
7 months ago
Brad Fitzpatrick ebc552d2e0 health: add Tracker type, in prep for removing global variables
This moves most of the health package global variables to a new
`health.Tracker` type.

But then rather than plumbing the Tracker in tsd.System everywhere,
this only goes halfway and makes one new global Tracker
(`health.Global`) that all the existing callers now use.

A future change will eliminate that global.

Updates #11874
Updates #4136

Change-Id: I6ee27e0b2e35f68cb38fecdb3b2dc4c3f2e09d68
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
7 months ago
Andrew Dunham 375617c5c8 net/tsdial: assume all connections are affected if no default route is present
If this happens, it results in us pessimistically closing more
connections than might be necessary, but is more correct since we won't
"miss" a change to the default route interface and keep trying to send
data over a nonexistent interface, or one that can't reach the internet.

Updates tailscale/corp#19124

Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
Change-Id: Ia0b8b04cb8cdcb0da0155fd08751c9dccba62c1a
7 months ago
kari-ts 048cb61dd0
interfaces: create android impl (#11784)
-Move Android impl into interfaces_android.go
-Instead of using ip route to get the interface name, use the one passed in by Android (ip route is restricted in Android 13+ per termux/termux-app#2993)

Follow-up will be to do the same for router

Fixes tailscale/corp#19215
Fixes tailscale/corp#19124

Signed-off-by: kari-ts <kari@tailscale.com>
7 months ago
Andrew Dunham b85c2b2313 net/dns/resolver: use SystemDial in DoH forwarder
This ensures that we close the underlying connection(s) when a major
link change happens. If we don't do this, on mobile platforms switching
between WiFi and cellular can result in leftover connections in the
http.Client's connection pool which are bound to the "wrong" interface.

Updates #10821
Updates tailscale/corp#19124

Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
Change-Id: Ibd51ce2efcaf4bd68e14f6fdeded61d4e99f9a01
7 months ago
Andrew Dunham 226486eb9a net/interfaces: handle removed interfaces in State.Equal
This wasn't previously handling the case where an interface in s2 was
removed and not present in s1, and would cause the Equal method to
incorrectly return that the states were equal.

Updates tailscale/corp#19124

Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
Change-Id: I3af22bc631015d1ddd0a1d01bfdf312161b9532d
7 months ago
Brad Fitzpatrick 7c1d6e35a5 all: use Go 1.22 range-over-int
Updates #11058

Change-Id: I35e7ef9b90e83cac04ca93fd964ad00ed5b48430
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
7 months ago
Brad Fitzpatrick 068db1f972 net/interfaces: delete unused unexported function
It should've been deleted in 11ece02f52.

Updates #9040

Change-Id: If8a136bdb6c82804af658c9d2b0a8c63ce02d509
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
7 months ago
Brad Fitzpatrick a1abd12f35 cmd/tailscaled, net/tstun: build for aix/ppc64
At least in userspace-networking mode.

Fixes #11361

Change-Id: I78d33f0f7e05fe9e9ee95b97c99b593f8fe498f2
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
8 months ago