In f77821fd63 (released in v1.72.0), we made the client tell a DERP server
when the connection was not its ideal choice (the first node in its region).
But we didn't do anything with that information until now. This adds a
metric about how many such connections are on a given derper, and also
adds a bit to the PeerPresentFlags bitmask so watchers can identify
(and rebalance) them.
Updates tailscale/corp#372
Change-Id: Ief8af448750aa6d598e5939a57c062f4e55962be
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Write timeouts can be indicative of stalled TCP streams. Understanding
changes in the rate of such events can be helpful in an ops context.
Updates tailscale/corp#23668
Signed-off-by: Jordan Whited <jordan@tailscale.com>
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>
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>
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>
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>
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>
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>
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>
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
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>
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>
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>
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>
~97% of the log messages derper outputs are related to the normal
non-error state of a client disconnecting in some manner. Add a
verbose logging feature that only logs these messages when enabled.
Fixes#8024
Signed-off-by: Val <valerie@tailscale.com>
* 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>
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>
Update all code generation tools, and those that check for license
headers to use the new standard header.
Also update copyright statement in LICENSE file.
Fixes#6865
Signed-off-by: Will Norris <will@tailscale.com>
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>
Instead of iterating over the map to determine the preferred forwarder
on every packet (which could happen concurrently with map mutations),
store it separately in an atomic variable.
Fixes#6445
Signed-off-by: Anton Tolchanov <anton@tailscale.com>
Periodically poll the TCP RTT metric from all open TCP connections and
update a (bucketed) histogram metric.
Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
Change-Id: I6214902196b05bf7829c9d0ea501ce0e13d984cf
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>
This allows tests to verfiy that a DERP connection was actually
established.
Related to #4326
Updates tailscale/corp#2579
Signed-off-by: Maisem Ali <maisem@tailscale.com>
A new package can also later record/report which knobs are checked and
set. It also makes the code cleaner & easier to grep for env knobs.
Change-Id: Id8a123ab7539f1fadbd27e0cbeac79c2e4f09751
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
