Commit Graph

113 Commits (978306565d0e9e9f1e5347969ddaeffe0f989cfe)

Author SHA1 Message Date
Kyle Carberry 6c852fa817 go.{mod,sum}: migrate from nhooyr.io/websocket to github.com/coder/websocket
Coder has just adopted nhooyr/websocket which unfortunately changes the import path.

`github.com/coder/coder` imports `tailscale.com/net/wsconn` which was still pointing
to `nhooyr.io/websocket`, but this change updates it.

See https://coder.com/blog/websocket

Updates #13154

Change-Id: I3dec6512472b14eae337ae22c5bcc1e3758888d5
Signed-off-by: Kyle Carberry <kyle@carberry.com>
3 months ago
Brad Fitzpatrick 6ca078c46e cmd/derper: move 204 handler from package main to derphttp
Updates #13038

Change-Id: I28a8284dbe49371cae0e9098205c7c5f17225b40
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 months ago
Brad Fitzpatrick f77821fd63 derp/derphttp: determine whether a region connect was to non-ideal node
... and then do approximately nothing with that information, other
than a big TODO. This is mostly me relearning this code and leaving
breadcrumbs for others in the future.

Updates #12724

Signed-off-by: Brad Fitzpatrick <brad@danga.com>
4 months ago
Brad Fitzpatrick 3485e4bf5a derp: make RunConnectionLoop funcs take Messages, support PeerPresentFlags
PeerPresentFlags was added in 5ffb2668ef but wasn't plumbed through to
the RunConnectionLoop. Rather than add yet another parameter (as
IP:port was added earlier), pass in the raw PeerPresentMessage and
PeerGoneMessage struct values, which are the same things, plus two
fields: PeerGoneReasonType for gone and the PeerPresentFlags from
5ffb2668ef.

Updates tailscale/corp#17816

Change-Id: Ib19d9f95353651ada90656071fc3656cf58b7987
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
5 months ago
Brad Fitzpatrick 15fc6cd966 derp/derphttp: fix netcheck HTTPS probes
The netcheck client, when no UDP is available, probes distance using
HTTPS.

Several problems:

* It probes using /derp/latency-check.
* But cmd/derper serves the handler at /derp/probe
* Despite the difference, it work by accident until c8f4dfc8c0
  which made netcheck's probe require a 2xx status code.
* in tests, we only use derphttp.Handler, so the cmd/derper-installed
  mux routes aren't preesnt, so there's no probe. That breaks
  tests in airplane mode. netcheck.Client then reports "unexpected
  HTTP status 426" (Upgrade Required)

This makes derp handle both /derp/probe and /derp/latency-check
equivalently, and in both cmd/derper and derphttp.Handler standalone
modes.

I notice this when wgengine/magicsock TestActiveDiscovery was failing
in airplane mode (no wifi). It still doesn't pass, but it gets
further.

Fixes #11989

Change-Id: I45213d4bd137e0f29aac8bd4a9ac92091065113f
6 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>
6 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 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 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 b27238b654 derp/derphttp: don't block in LocalAddr method
The derphttp.Client mutex is held during connects (for up to 10
seconds) so this LocalAddr method (blocking on said mutex) could also
block for up to 10 seconds, causing a pileup upstream in
magicsock/wgengine and ultimately a watchdog timeout resulting in a
crash.

Updates #11519

Change-Id: Idd1d94ee00966be1b901f6899d8b9492f18add0f
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
7 months ago
Brad Fitzpatrick 3e6306a782 derp/derphttp: make CONNECT Host match request-target's authority-form
This CONNECT client doesn't match what Go's net/http.Transport does
(making the two values match).  This makes it match.

This is all pretty unspecified but most clients & doc examples show
these matching. And some proxy implementations (such as Zscaler) care.

Updates tailscale/corp#18716

Change-Id: I135c5facbbcec9276faa772facbde1bb0feb2d26
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
8 months ago
Brad Fitzpatrick 2bd3c1474b util/cmpx: delete now that we're using Go 1.22
Updates #11058

Change-Id: I09dea8e86f03ec148b715efca339eab8b1f0f644
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
9 months ago
Anton Tolchanov ef6a6e94f1 derp/derphttp: use a getter method to read server key
To hold the mutex while accessing it.

Fixes #10122

Signed-off-by: Anton Tolchanov <anton@tailscale.com>
1 year ago
Brad Fitzpatrick b2b836214c derp/derphttp: fix derptrack fix
3d7fb6c21d dropped the explicit called to (*Client).connect when
its (*Client).WatchConnectionChanges got removed+refactored.

This puts it back, but in RunWatchConnectionLoop, before the call
to the (*Client).ServerPublicKey accessor, which is documented to
return the zero value (which is what broke us) on an unconnected
connection.

Plus some tests.

Fixes tailscale/corp#15604

Change-Id: I0f242816f5ee4ad3bb0bf0400abc961dbe9f5fc8
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
1 year ago
Anton Tolchanov c3313133b9 derp/derphttp: close DERP client to avoid data race in test
Fixes #10041

Signed-off-by: Anton Tolchanov <anton@tailscale.com>
1 year ago
Anton Tolchanov 3114a1c88d derp/derphttp: add watch reconnection tests from #9719
Co-authored-by: Val <valerie@tailscale.com>
Signed-off-by: Anton Tolchanov <anton@tailscale.com>
1 year ago
Brad Fitzpatrick 3d7fb6c21d derp/derphttp: fix race in mesh watcher
The derphttp client automatically reconnects upon failure.

RunWatchConnectionLoop called derphttp.Client.WatchConnectionChanges
once, but that wrapper method called the underlying
derp.Client.WatchConnectionChanges exactly once on derphttp.Client's
currently active connection. If there's a failure, we need to re-subscribe
upon all reconnections.

This removes the derphttp.Client.WatchConnectionChanges method, which
was basically impossible to use correctly, and changes it to be a
boolean field on derphttp.Client alongside MeshKey and IsProber. Then
it moves the call to the underlying derp.Client.WatchConnectionChanges
to derphttp's client connection code, so it's resubscribed on any
reconnect.

Some paranoia is then added to make sure people hold the API right,
not calling derphttp.Client.RunWatchConnectionLoop on an
already-started Client without having set the bool to true. (But still
auto-setting it to true if that's the first method that's been called
on that derphttp.Client, as is commonly the case, and prevents
existing code from breaking)

Fixes tailscale/corp#9916
Supercedes tailscale/tailscale#9719

Co-authored-by: Val <valerie@tailscale.com>
Co-authored-by: Irbe Krumina <irbe@tailscale.com>
Co-authored-by: Anton Tolchanov <anton@tailscale.com>
Signed-off-by: Brad Fitzpatrick <brad@danga.com>
1 year ago
Thomas Kosiewski b2ae8fdf80
derp/derphttp: strip port numbers from URL hostname
When trying to set up multiple derper instances meshing with each
other, it turned out that while one can specify an alternative
listening port using the -a flag, the TLS hostname gets incorrectly
determined and includes the set alternative listening port as part of
the hostname. Thus, the TLS hostname validation always fails when the
-mesh-with values have ports.

Updates #9949

Signed-off-by: Thomas Kosiewski <thomas.kosiewski@loft.sh>
1 year ago
David Anderson 8b492b4121 net/wsconn: accept a remote addr string and plumb it through
This makes wsconn.Conns somewhat present reasonably when they are
the client of an http.Request, rather than just put a placeholder
in that field.

Updates tailscale/corp#13777

Signed-off-by: David Anderson <danderson@tailscale.com>
1 year ago
Brad Fitzpatrick 3bce9632d9 derp/derphttp: fix data race and crash in proxy dial error path
Named result meant error paths assigned that variable to nil.
But a goroutine was concurrently using that variable.

Don't use a named result for that first parameter. Then then return
paths don't overwrite it.

Fixes #9129

Change-Id: Ie57f99d40ca8110085097780686d9bd620aaf160
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
1 year ago
Brad Fitzpatrick 6c791f7d60 derp: include src IPs in mesh watch messages
Updates tailscale/corp#13945

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
1 year ago
Brad Fitzpatrick 5ebb271322 derp/derphttp: add optional Client.BaseContext hook
Like net/http.Server.BaseContext, this lets callers specify a base
context for dials.

Updates tailscale/corp#12702

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
1 year ago
Claire Wang 90a7d3066c
derp: use tstime (#8634)
Updates #8587

Signed-off-by: Claire Wang <claire@tailscale.com>
1 year ago
Brad Fitzpatrick eefee6f149 all: use cmpx.Or where it made sense
I left a few out where writing it explicitly was better
for various reasons.

Updates #8296

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
1 year ago
Mihai Parparita 7330aa593e all: avoid repeated default interface lookups
On some platforms (notably macOS and iOS) we look up the default
interface to bind outgoing connections to. This is both duplicated
work and results in logspam when the default interface is not available
(i.e. when a phone has no connectivity, we log an error and thus cause
more things that we will try to upload and fail).

Fixed by passing around a netmon.Monitor to more places, so that we can
use its cached interface state.

Fixes #7850
Updates #7621

Signed-off-by: Mihai Parparita <mihai@tailscale.com>
2 years ago
Mihai Parparita edb02b63f8 net/sockstats: pass in logger to sockstats.WithSockStats
Using log.Printf may end up being printed out to the console, which
is not desirable. I noticed this when I was investigating some client
logs with `sockstats: trace "NetcheckClient" was overwritten by another`.
That turns to be harmless/expected (the netcheck client will fall back
to the DERP client in some cases, which does its own sockstats trace).

However, the log output could be visible to users if running the
`tailscale netcheck` CLI command, which would be needlessly confusing.

Updates tailscale/corp#9230

Signed-off-by: Mihai Parparita <mihai@tailscale.com>
2 years ago
valscale 7bfb7744b7
derp,magicsock: add debug envknobs for HTTP and derp server name (#7744)
Make developing derp easier by:

1. Creating an envknob telling clients to use HTTP to connect to derp
servers, so devs don't have to acquire a valid TLS cert.

2. Creating an envknob telling clients which derp server to connect
to, so devs don't have to edit the ACLs in the admin console to add a
custom DERP map.

3. Explaining how the -dev and -a command lines args to derper
interact.

To use this:

1. Run derper with -dev.

2. Run tailscaled with TS_DEBUG_USE_DERP_HTTP=1 and
TS_DEBUG_USE_DERP_ADDR=localhost

This will result in the client connecting to derp via HTTP on port
3340.

Fixes #7700

Signed-off-by: Val <valerie@tailscale.com>
2 years ago
valscale 74eb99aed1
derp, derphttp, magicsock: send new unknown peer frame when destination is unknown (#7552)
* wgengine/magicsock: add envknob to send CallMeMaybe to non-existent peer

For testing older client version responses to the PeerGone packet format change.

Updates #4326

Signed-off-by: Val <valerie@tailscale.com>

* derp: remove dead sclient struct member replaceLimiter

Leftover from an previous solution to the duplicate client problem.

Updates #2751

Signed-off-by: Val <valerie@tailscale.com>

* derp, derp/derphttp, wgengine/magicsock: add new PeerGone message type Not Here

Extend the PeerGone message type by adding a reason byte. Send a
PeerGone "Not Here" message when an endpoint sends a disco message to
a peer that this server has no record of.

Fixes #4326

Signed-off-by: Val <valerie@tailscale.com>

---------

Signed-off-by: Val <valerie@tailscale.com>
2 years ago
Anton Tolchanov 654b5a0616 derp: add optional debug logging for prober clients
This allows tracking packet flow via logs for prober clients. Note that
the new sclient.debug() function is called on every received packet, but
will do nothing for most clients.

I have adjusted sclient logging to print public keys in short format
rather than full. This takes effect even for existing non-debug logging
(mostly client disconnect messages).

Example logs for a packet being sent from client [SbsJn] (connected to
derper [dM2E3]) to client [10WOo] (connected to derper [AVxvv]):

```
derper [dM2E3]:
derp client 10.0.0.1:35470[SbsJn]: register single client mesh("10.0.1.1"): 4 peers
derp client 10.0.0.1:35470[SbsJn]: read frame type 4 len 40 err <nil>
derp client 10.0.0.1:35470[SbsJn]: SendPacket for [10WOo], forwarding via <derphttp_client.Client [AVxvv] url=https://10.0.1.1/derp>: <nil>
derp client 10.0.0.1:35470[SbsJn]: read frame type 0 len 0 err EOF
derp client 10.0.0.1:35470[SbsJn]: read EOF
derp client 10.0.0.1:35470[SbsJn]: sender failed: context canceled
derp client 10.0.0.1:35470[SbsJn]: removing connection

derper [AVxvv]:
derp client 10.0.1.1:50650[10WOo]: register single client
derp client 10.0.1.1:50650[10WOo]: received forwarded packet from [SbsJn] via [dM2E3]
derp client 10.0.1.1:50650[10WOo]: sendPkt attempt 0 enqueued
derp client 10.0.1.1:50650[10WOo]: sendPacket from [SbsJn]: <nil>
derp client 10.0.1.1:50650[10WOo]: read frame type 0 len 0 err EOF
derp client 10.0.1.1:50650[10WOo]: read EOF
derp client 10.0.1.1:50650[10WOo]: sender failed: context canceled
derp client 10.0.1.1:50650[10WOo]: removing connection
```

Signed-off-by: Anton Tolchanov <anton@tailscale.com>
2 years ago
Kyle Carberry 3862a1e1d5 derp/derphttp: cleanup WebSocket connection on close
This was causing a leak in our CI!

Signed-off-by: Kyle Carberry <kyle@carberry.com>
2 years ago
Mihai Parparita 6ac6ddbb47 sockstats: switch label to enum
Makes it cheaper/simpler to persist values, and encourages reuse of
labels as opposed to generating an arbitrary number.

Updates tailscale/corp#9230
Updates #3363

Signed-off-by: Mihai Parparita <mihai@tailscale.com>
2 years ago
Mihai Parparita 9cb332f0e2 sockstats: instrument networking code paths
Uses the hooks added by tailscale/go#45 to instrument the reads and
writes on the major code paths that do network I/O in the client. The
convention is to use "<package>.<type>:<label>" as the annotation for
the responsible code path.

Enabled on iOS, macOS and Android only, since mobile platforms are the
ones we're most interested in, and we are less sensitive to any
throughput degradation due to the per-I/O callback overhead (macOS is
also enabled for ease of testing during development).

For now just exposed as counters on a /v0/sockstats PeerAPI endpoint.

We also keep track of the current interface so that we can break out
the stats by interface.

Updates tailscale/corp#9230
Updates #3363

Signed-off-by: Mihai Parparita <mihai@tailscale.com>
2 years ago
Brad Fitzpatrick cf8dd7aa09 all: use Go 1.20's bytes.Clone
Updates #7123
Updates #6257 (more to do in other repos)

Change-Id: I073e2a6d81a5d7fbecc29caddb7e057ff65239d0
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Brad Fitzpatrick b1248442c3 all: update to Go 1.20, use strings.CutPrefix/Suffix instead of our fork
Updates #7123
Updates #5309

Change-Id: I90bcd87a2fb85a91834a0dd4be6e03db08438672
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Will Norris 71029cea2d all: update copyright and license headers
This updates all source files to use a new standard header for copyright
and license declaration.  Notably, copyright no longer includes a date,
and we now use the standard SPDX-License-Identifier header.

This commit was done almost entirely mechanically with perl, and then
some minimal manual fixes.

Updates #6865

Signed-off-by: Will Norris <will@tailscale.com>
2 years ago
Mihai Parparita 33520920c3 all: use strs.CutPrefix and strs.CutSuffix more
Updates places where we use HasPrefix + TrimPrefix to use the combined
function.

Updates #5309

Signed-off-by: Mihai Parparita <mihai@tailscale.com>
2 years ago
Brad Fitzpatrick da8def8e13 all: remove old +build tags
The //go:build syntax was introduced in Go 1.17:

https://go.dev/doc/go1.17#build-lines

gofmt has kept the +build and go:build lines in sync since
then, but enough time has passed. Time to remove them.

Done with:

    perl -i -npe 's,^// \+build.*\n,,' $(git grep -l -F '+build')

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Mihai Parparita 9d04ffc782 net/wsconn: add back custom wrapper for turning a websocket.Conn into a net.Conn
We removed it in #4806 in favor of the built-in functionality from the
nhooyr.io/websocket package. However, it has an issue with deadlines
that has not been fixed yet (see nhooyr/websocket#350). Temporarily
go back to using a custom wrapper (using the fix from our fork) so that
derpers will stop closing connections too aggressively.

Updates #5921

Signed-off-by: Mihai Parparita <mihai@tailscale.com>
2 years ago
Mihai Parparita b2855cfd86 derp/derphttp: fix nil pointer dereference when closing a netcheck client
NewNetcheckClient only initializes a subset of fields of derphttp.Client,
and the Close() call added by #5707 was result in a nil pointer dereference.
Make Close() safe to call when using NewNetcheckClient() too.

Fixes #5919

Signed-off-by: Mihai Parparita <mihai@tailscale.com>
2 years ago
Josh Soref d4811f11a0 all: fix spelling mistakes
Signed-off-by: Josh Soref <2119212+jsoref@users.noreply.github.com>
2 years ago
Eng Zer Jun f0347e841f refactor: move from io/ioutil to io and os packages
The io/ioutil package has been deprecated as of Go 1.16 [1]. This commit
replaces the existing io/ioutil functions with their new definitions in
io and os packages.

Reference: https://golang.org/doc/go1.16#ioutil
Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>
2 years ago
Maisem Ali a9f6cd41fd all: use syncs.AtomicValue
Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
Brad Fitzpatrick a12aad6b47 all: convert more code to use net/netip directly
perl -i -npe 's,netaddr.IPPrefixFrom,netip.PrefixFrom,' $(git grep -l -F netaddr.)
    perl -i -npe 's,netaddr.IPPortFrom,netip.AddrPortFrom,' $(git grep -l -F netaddr. )
    perl -i -npe 's,netaddr.IPPrefix,netip.Prefix,g' $(git grep -l -F netaddr. )
    perl -i -npe 's,netaddr.IPPort,netip.AddrPort,g' $(git grep -l -F netaddr. )
    perl -i -npe 's,netaddr.IP\b,netip.Addr,g' $(git grep -l -F netaddr. )
    perl -i -npe 's,netaddr.IPv6Raw\b,netip.AddrFrom16,g' $(git grep -l -F netaddr. )
    goimports -w .

Then delete some stuff from the net/netaddr shim package which is no
longer neeed.

Updates #5162

Change-Id: Ia7a86893fe21c7e3ee1ec823e8aba288d4566cd8
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Brad Fitzpatrick 6a396731eb all: use various net/netip parse funcs directly
Mechanical change with perl+goimports.

Changed {Must,}Parse{IP,IPPrefix,IPPort} to their netip variants, then
goimports -d .

Finally, removed the net/netaddr wrappers, to prevent future use.

Updates #5162

Change-Id: I59c0e38b5fbca5a935d701645789cddf3d7863ad
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Brad Fitzpatrick 7eaf5e509f net/netaddr: start migrating to net/netip via new netaddr adapter package
Updates #5162

Change-Id: Id7bdec303b25471f69d542f8ce43805328d56c12
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Charlotte Brandhorst-Satzkorn 4c0feba38e
derp: plumb '/derp' request context through (#5083)
This change is required to implement tracing for derp.

Signed-off-by: Charlotte Brandhorst-Satzkorn <charlotte@tailscale.com>
2 years ago
Mihai Parparita edc90ebc61 net/wsconn: remove homegrown wrapper for turning a websocket.Conn into a net.Conn
The one from the nhooyr/websocket package seems to work equally well.

Signed-off-by: Mihai Parparita <mihai@tailscale.com>
2 years ago
Mihai Parparita a9f32656f5 control/controlhttp: allow client and server to communicate over WebSockets
We can't do Noise-over-HTTP in Wasm/JS (because we don't have bidirectional
communication), but we should be able to do it over WebSockets. Reuses
derp WebSocket support that allows us to turn a WebSocket connection
into a net.Conn.

Updates #3157

Signed-off-by: Mihai Parparita <mihai@tailscale.com>
2 years ago
Tom DNetto c8f4dfc8c0 derp/derphttp,net/netcheck: improve netcheck behavior under MITM proxies
In cases where tailscale is operating behind a MITM proxy, we need to consider
that a lot more of the internals of our HTTP requests are visible and may be
used as part of authorization checks. As such, we need to 'behave' as closely
as possible to ideal.

 - Some proxies do authorization or consistency checks based the on Host header
   or HTTP URI, instead of just the IP/hostname/SNI. As such, we need to
   construct a `*http.Request` with a valid URI everytime HTTP is going to be
   used on the wire, even if its over TLS.
   Aside from the singular instance in net/netcheck, I couldn't find anywhere
   else a http.Request was constructed incorrectly.

 - Some proxies may deny requests, typically by returning a 403 status code. We
   should not consider these requests as a valid latency check, so netcheck
   semantics have been updated to consider >299 status codes as a failed probe.

Signed-off-by: Tom DNetto <tom@tailscale.com>
3 years ago
Brad Fitzpatrick 730aa1c89c derp/derphttp, wgengine/magicsock: prefer IPv6 to DERPs when IPv6 works
Fixes #3838

Change-Id: Ie47a2a30c7e8e431512824798d2355006d72fb6a
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago