Commit graph

16 commits

Author SHA1 Message Date
Josh Bleecher Snyder 63066ce406 device: fix persistent_keepalive_interval data races
Co-authored-by: David Anderson <danderson@tailscale.com>
Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
2021-01-07 14:49:44 +01:00
Josh Bleecher Snyder e1fa1cc556 device: use channel close to shut down and drain encryption channel
The new test introduced in this commit used to deadlock about 1% of the time.

I believe that the deadlock occurs as follows:

* The test completes, calling device.Close.
* device.Close closes device.signals.stop.
* RoutineEncryption stops.
* The deferred function in RoutineEncryption drains device.queue.encryption.
* RoutineEncryption exits.
* A peer's RoutineNonce processes an element queued in peer.queue.nonce.
* RoutineNonce puts that element into the outbound and encryption queues.
* RoutineSequentialSender reads that elements from the outbound queue.
* It waits for that element to get Unlocked by RoutineEncryption.
* RoutineEncryption has already exited, so RoutineSequentialSender blocks forever.
* device.RemoveAllPeers calls peer.Stop on all peers.
* peer.Stop waits for peer.routines.stopping, which blocks forever.

Rather than attempt to add even more ordering to the already complex
centralized shutdown orchestration, this commit moves towards a
data-flow-oriented shutdown.

The device.queue.encryption gets closed when there will be no more writes to it.
All device.queue.encryption readers always read until the channel is closed and then exit.
We thus guarantee that any element that enters the encryption queue also exits it.
This removes the need for central control of the lifetime of RoutineEncryption,
removes the need to drain the encryption queue on shutdown, and simplifies RoutineEncryption.

This commit also fixes a data race. When RoutineSequentialSender
drains its queue on shutdown, it needs to lock the elem before operating on it,
just as the main body does.

The new test in this commit passed 50k iterations with the race detector enabled
and 150k iterations with the race detector disabled, with no failures.

Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
2021-01-07 14:49:44 +01:00
Josh Bleecher Snyder c9e4a859ae device: remove starting waitgroups
In each case, the starting waitgroup did nothing but ensure
that the goroutine has launched.

Nothing downstream depends on the order in which goroutines launch,
and if the Go runtime scheduler is so broken that goroutines
don't get launched reasonably promptly, we have much deeper problems.

Given all that, simplify the code.

Passed a race-enabled stress test 25,000 times without failure.

Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
2021-01-07 14:49:44 +01:00
Dmytro Shynkevych 4369db522b device: wait for routines to stop before removing peers
Peers are currently removed after Device's goroutines are signaled to stop,
but without waiting for them to actually do so, which is racy.

For example, RoutineHandshake may be in Peer.SendKeepalive
when the corresponding peer is removed, which closes its nonce channel.
This causes a send on a closed channel, as observed in tailscale/tailscale#487.

This patch seems to be the correct synchronizing action:
Peer's goroutines are receivers and handle channel closure gracefully,
so Device's goroutines are the ones that should be fully stopped first.

Signed-Off-By: Dmytro Shynkevych <dmytro@tailscale.com>
2020-07-04 20:29:31 +10:00
David Crawshaw b84f1d4db2 device: export Bind and remove socketfd shims for android
Signed-off-by: David Crawshaw <crawshaw@tailscale.com>
2020-06-22 10:42:28 +10:00
Jason A. Donenfeld db0aa39b76 global: update header comments and modules
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2020-05-02 02:08:26 -06:00
David Crawshaw 203554620d conn: introduce new package that splits out the Bind and Endpoint types
The sticky socket code stays in the device package for now,
as it reaches deeply into the peer list.

This is the first step in an effort to split some code out of
the very busy device package.

Signed-off-by: David Crawshaw <crawshaw@tailscale.com>
2020-05-02 01:46:42 -06:00
Jason A. Donenfeld 4739708ca4 noise: unify zero checking of ecdh 2020-03-17 23:07:14 -06:00
Jason A. Donenfeld 6ed56ff2df device: fix private key removal logic 2020-02-04 22:02:53 +01:00
Jason A. Donenfeld 4be9630ddc device: drop lock before expiring keys 2019-08-05 17:46:34 +02:00
Jason A. Donenfeld a961aacc9f device: immediately rekey all peers after changing device private key
Reported-by: Derrick Pallas <derrick@pallas.us>
2019-07-11 17:37:35 +02:00
Matt Layher 1f48971a80 tun: remove TUN prefix from types to reduce stutter elsewhere
Signed-off-by: Matt Layher <mdlayher@gmail.com>
2019-06-14 18:35:57 +02:00
Jason A. Donenfeld d9f995209c device: add SendKeepalivesToPeersWithCurrentKeypair for handover 2019-05-30 15:16:16 +02:00
Jason A. Donenfeld c718f3940d device: fail to give bind if it doesn't exist 2019-05-17 15:35:20 +02:00
Jason A. Donenfeld 3bf41b06ae global: regroup all imports 2019-05-14 09:09:52 +02:00
Jason A. Donenfeld 69f0fe67b6 global: begin modularization 2019-03-03 05:00:40 +01:00
Renamed from device.go (Browse further)