Commit Graph

269 Commits (d837e0252f0ce9bd0a153c0911688e7e13a08a32)

Author SHA1 Message Date
Brad Fitzpatrick e1bbe1bf45 derp: document the RunWatchConnectionLoop callback gotchas
Updates #13566

Change-Id: I497b5adc57f8b1b97dbc3f74c0dc67140caad436
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 months ago
Brad Fitzpatrick 8012bb4216 derp: refactor DERP server's peer-gone watch mechanism
In prep for upcoming flow tracking & mutex contention optimization
changes, this change refactors (subjectively simplifying) how the DERP
Server accounts for which peers have written to which other peers, to
be able to send PeerGoneReasonDisconnected messages to writes to
uncache their DRPO (DERP Return Path Optimization) routes.

Notably, this removes the Server.sentTo field which was guarded by
Server.mu and checked on all packet sends. Instead, the accounting is
moved to each sclient's sendLoop goroutine and now only needs to
acquire Server.mu for newly seen senders, the first time a peer sends
a packet to that sclient.

This change reduces the number of reasons to acquire Server.mu
per-packet from two to one. Removing the last one is the subject of an
upcoming change.

Updates #3560
Updates #150

Change-Id: Id226216d6629d61254b6bfd532887534ac38586c
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 months ago
Brad Fitzpatrick aa15a63651 derp: add new concurrent server benchmark
In prep for reducing mutex contention on Server.mu.

Updates #3560

Change-Id: Ie95e7c6dc9f4b64b6f79b3b2338f8cd86c688d98
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 months ago
Brad Fitzpatrick cec779e771 util/slicesx: add FirstElementEqual and LastElementEqual
And update a few callers as examples of motivation. (there are a
couple others, but these are the ones where it's prettier)

Updates #cleanup

Change-Id: Ic8c5cb7af0a59c6e790a599136b591ebe16d38eb
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 months ago
Brad Fitzpatrick 910462a8e0 derp: unify server's clientSet interface into concrete type
73280595a8 for #2751 added a "clientSet" interface to
distinguish the two cases of a client being singly connected (the
common case) vs tolerating multiple connections from the client at
once. At the time (three years ago) it was kinda an experiment
and we didn't know whether it'd stop the reconnect floods we saw
from certain clients. It did.

So this promotes it to a be first-class thing a bit, removing the
interface. The old tests from 73280595a were invaluable in ensuring
correctness while writing this change (they failed a bunch).

But the real motivation for this change is that it'll permit a future
optimization to add flow tracking for stats & performance where we
don't contend on Server.mu for each packet sent via DERP. Instead,
each client can track its active flows and hold on to a *clientSet and
ask the clientSet per packet what the active client is via one atomic
load rather than a mutex. And if the atomic load returns nil, we'll
know we need to ask the server to see if they died and reconnected and
got a new clientSet. But that's all coming later.

Updates #3560

Change-Id: I9ccda3e5381226563b5ec171ceeacf5c210e1faf
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 months ago
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>
4 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 c6af5bbfe8 all: add test for package comments, fix, add comments as needed
Updates #cleanup

Change-Id: Ic4304e909d2131a95a38b26911f49e7b1729aaef
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
5 months ago
James Tucker 114d1caf55 derp/xdp: retain the link so that the fd is not closed
BPF links require that the owning FD remains open, this FD is embedded
into the RawLink returned by the attach function and must live for the
duration of the server.

Updates ENG-4274

Signed-off-by: James Tucker <james@tailscale.com>
5 months ago
Brad Fitzpatrick 210264f942 cmd/derper: clarify that derper and tailscaled need to be in sync
Fixes #12617

Change-Id: Ifc87b7d9cf699635087afb57febd01fb9a6d11b7
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
5 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 d91e5c25ce derp: redo, simplify how mesh update writes are queued/written
I couldn't convince myself the old way was safe and couldn't lose
writes.

And it seemed too complicated.

Updates tailscale/corp#21104

Change-Id: I17ba7c7d6fd83458a311ac671146a1f6a458a5c1
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
5 months ago
Brad Fitzpatrick ded7734c36 derp: account for increased size of peerPresent messages in mesh updates
sendMeshUpdates tries to write as much as possible without blocking,
being careful to check the bufio.Writer.Available size before writes.

Except that regressed in 6c791f7d60 which made those messages larger, which
meants we were doing network I/O with the Server mutex held.

Updates tailscale/corp#13945

Change-Id: Ic327071d2e37de262931b9b390cae32084811919
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
5 months ago
Brad Fitzpatrick 5ffb2668ef derp: add PeerPresentFlags bitmask to Watch messages
Updates tailscale/corp#17816

Change-Id: Ib5baf6c981a6a4c279f8bbfef02048cfbfb3323b
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
5 months ago
Brad Fitzpatrick 25eeafde23 derp: don't verify mesh peers when --verify-clients is set
Updates tailscale/corp#20654

Change-Id: I33c7ca3c7a3c4e492797b73c66eefb699376402c
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
5 months ago
Brad Fitzpatrick 4b39b6f7ce derp: fix fmt verb for nodekeys
It was hex-ifying the String() form of key.NodePublic, which was already hex.
I noticed in some logs:

    "client 6e6f64656b65793a353537353..."

And thought that 6x6x6x6x looked strange. It's "nodekey:" in hex.

Updates tailscale/corp#20844

Change-Id: Ib9f2d63b37e324420b86efaa680668a9b807e465
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
5 months ago
Jordan Whited a93173b56a
cmd/xdpderper,derp/xdp: implement mode that drops STUN packets (#12527)
This is useful during maintenance as a method for shedding home client
load.

Updates tailscale/corp#20689

Signed-off-by: Jordan Whited <jordan@tailscale.com>
5 months ago
James Tucker 87c5ad4c2c derp: add a verifyClients check to the consistency check
Only implemented for the local tailscaled variant for now.

Updates tailscale/corp#20844

Signed-off-by: James Tucker <james@tailscale.com>
5 months ago
Jordan Whited 315f3d5df1
derp/xdp: fix handling of zero value UDP checksums (#12510)
validate_udp_checksum was previously indeterminate (not zero) at
declaration, and IPv4 zero value UDP checksum packets were being passed
to the kernel.

Updates tailscale/corp#20689

Signed-off-by: Jordan Whited <jordan@tailscale.com>
5 months ago
Jordan Whited 65888d95c9
derp/xdp,cmd/xdpderper: initial skeleton (#12390)
This commit introduces a userspace program for managing an experimental
eBPF XDP STUN server program. derp/xdp contains the eBPF pseudo-C along
with a Go pkg for loading it and exporting its metrics.
cmd/xdpderper is a package main user of derp/xdp.

Updates tailscale/corp#20689

Signed-off-by: Jordan Whited <jordan@tailscale.com>
5 months ago
Brad Fitzpatrick 6908fb0de3 ipn/localapi,client/tailscale,cmd/derper: add WhoIs lookup by nodekey, use in derper
Fixes #12465

Change-Id: I9b7c87315a3d2b2ecae2b8db9e94b4f5a1eef74a
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
5 months ago
Maisem Ali 4a8cb1d9f3 all: use math/rand/v2 more
Updates #11058

Signed-off-by: Maisem Ali <maisem@tailscale.com>
6 months ago
Brad Fitzpatrick f227083539 derp: add some guardrails for derpReason metrics getting out of sync
The derp metrics got out of sync in 74eb99aed1 (2023-03).

They were fixed in 0380cbc90d (2024-05).

This adds some further guardrails (atop the previous fix) to make sure
they don't get out of sync again.

Updates #12288

Change-Id: I809061a81f8ff92f45054d0253bc13871fc71634
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
6 months ago
Spike Curtis 0380cbc90d
derp: fix dropReason metrics labels (#12288)
Updates #2745
Updates #7552

Signed-off-by: Spike Curtis <spike@coder.com>
6 months ago
Andrew Dunham c6d42b1093 derp: remove stats goroutine, use a timer
Without changing behaviour, don't create a goroutine per connection that
sits and sleeps, but rather use a timer that wakes up and gathers
statistics on a regular basis.

Fixes #12127

Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
Change-Id: Ibc486447e403070bdc3c2cd8ae340e7d02854f21
6 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
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
Maisem Ali a49ed2e145 derp,ipn/ipnlocal: stop calling rand.Seed
It's deprecated and using it gets us the old slow behavior
according to https://go.dev/blog/randv2.

> Having eliminated repeatability of the global output stream, Go 1.20
> was also able to make the global generator scale better in programs
> that don’t call rand.Seed, replacing the Go 1 generator with a very
> cheap per-thread wyrand generator already used inside the Go
> runtime. This removed the global mutex and made the top-level
> functions scale much better. Programs that do call rand.Seed fall
> back to the mutex-protected Go 1 generator.

Updates #7123

Change-Id: Ia5452e66bd16b5457d4b1c290a59294545e13291
Signed-off-by: Maisem Ali <maisem@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 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>
8 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 10d130b845 cmd/derper, derp, tailcfg: add admission controller URL option
So derpers can check an external URL for whether to permit access
to a certain public key.

Updates tailscale/corp#17693

Change-Id: I8594de58f54a08be3e2dbef8bcd1ff9b728ab297
Co-authored-by: Maisem Ali <maisem@tailscale.com>
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
9 months ago
Brad Fitzpatrick 2988c1ec52 derp: plumb context to Server.verifyClient
Updates tailscale/corp#17693

Change-Id: If17e02c77d5ad86b820e639176da2d3e61296bae
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
9 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>
10 months ago
James Tucker 7100b6e721 derp: optimize another per client field alignment
Updates #self

Signed-off-by: James Tucker <james@tailscale.com>
11 months ago
James Tucker ee20327496 derp: remove unused per-client struct field
Updates #self

Signed-off-by: James Tucker <james@tailscale.com>
11 months ago
James Tucker a7f65b40c5 derp: optimize field order to reduce GC cost
See the field alignment lints for more information.
Reductions are 64->24 and 64->32 respectively.

Updates #self

Signed-off-by: James Tucker <james@tailscale.com>
11 months ago
James Tucker ff9c1ebb4a derp: reduce excess goroutines blocking on broadcasts
Observed on one busy derp node, there were 600 goroutines blocked
writing to this channel, which represents not only more blocked routines
than we need, but also excess wake-ups downstream as the latent
goroutines writes represent no new work.

Updates #self

Signed-off-by: James Tucker <james@tailscale.com>
11 months ago
Andrew Lytvynov 2716250ee8
all: cleanup unused code, part 2 (#10670)
And enable U1000 check in staticcheck.

Updates #cleanup

Signed-off-by: Andrew Lytvynov <awly@tailscale.com>
11 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