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path: root/device/send.go
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2021-01-20device: remove QueueOutboundElement.droppedJosh Bleecher Snyder
If we block when enqueuing encryption elements to the queue, then we never drop them. Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
2021-01-20device: remove selects from encrypt/decrypt/inbound/outbound enqueuingJosh Bleecher Snyder
Block instead. Backpressure here is fine, probably preferable. This reduces code complexity. Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
2021-01-07device: call wg.Add outside the goroutineJosh Bleecher Snyder
One of the first rules of WaitGroups is that you call wg.Add outside of a goroutine, not inside it. Fix this embarrassing mistake. This prevents an extremely rare race condition (2 per 100,000 runs) which could occur when attempting to start a new peer concurrently with shutting down a device. Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
2021-01-07device: add missing colon to error lineJason A. Donenfeld
People are actually hitting this condition, so make it uniform. Also, change a printf into a println, to match the other conventions. Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2021-01-07device: fix races from changing private_keyJosh Bleecher Snyder
Access keypair.sendNonce atomically. Eliminate one unnecessary initialization to zero. Mutate handshake.lastSentHandshake with the mutex held. Co-authored-by: David Anderson <danderson@tailscale.com> Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
2021-01-07device: always name *Queue*Element variables elemJosh Bleecher Snyder
They're called elem in most places. Rename a few local variables to make it consistent. This makes it easier to grep the code for things like elem.Drop. Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
2021-01-07device: use channel close to shut down and drain outbound channelJosh Bleecher Snyder
This is a similar treatment to the handling of the encryption channel found a few commits ago: Use the closing of the channel to manage goroutine lifetime and shutdown. It is considerably simpler because there is only a single writer. Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
2021-01-07device: use channel close to shut down and drain encryption channelJosh Bleecher Snyder
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>
2021-01-07device: remove starting waitgroupsJosh Bleecher Snyder
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>
2020-12-08device: clear pointers when returning elems to poolsJosh Bleecher Snyder
Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
2020-12-08device: use labeled for loop instead of gotoJosh Bleecher Snyder
Minor code cleanup; no functional changes. Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
2020-11-18device: add write queue mutex for peerHaichao Liu
fix panic: send on closed channel when remove peer Signed-off-by: Haichao Liu <liuhaichao@bytedance.com> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2020-05-18device: rework padding calculation and don't shadow paddedSizeJason A. Donenfeld
Reported-by: Jayakumar S <jayakumar82.s@gmail.com> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2020-05-02global: update header comments and modulesJason A. Donenfeld
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2020-02-14send: account for zero mtuJason A. Donenfeld
Don't divide by zero.
2019-10-21device: remove dead error reporting codeJason A. Donenfeld
2019-06-11device: update transfer counters correctlyJason A. Donenfeld
The rule is to always update them to the full packet size minus UDP/IP encapsulation for all authenticated packet types.
2019-06-03device, ratelimiter: replace uses of time.Now().Sub() with time.Since()Matt Layher
Simplification found by staticcheck: $ staticcheck ./... | grep S1012 device/cookie.go:90:5: should use time.Since instead of time.Now().Sub (S1012) device/cookie.go:127:5: should use time.Since instead of time.Now().Sub (S1012) device/cookie.go:242:5: should use time.Since instead of time.Now().Sub (S1012) device/noise-protocol.go:304:13: should use time.Since instead of time.Now().Sub (S1012) device/receive.go:82:46: should use time.Since instead of time.Now().Sub (S1012) device/send.go:132:5: should use time.Since instead of time.Now().Sub (S1012) device/send.go:139:5: should use time.Since instead of time.Now().Sub (S1012) device/send.go:235:59: should use time.Since instead of time.Now().Sub (S1012) device/send.go:393:9: should use time.Since instead of time.Now().Sub (S1012) ratelimiter/ratelimiter.go:79:10: should use time.Since instead of time.Now().Sub (S1012) ratelimiter/ratelimiter.go:87:10: should use time.Since instead of time.Now().Sub (S1012) Change applied using: $ find . -type f -name "*.go" -exec sed -i "s/Now().Sub(/Since(/g" {} \; Signed-off-by: Matt Layher <mdlayher@gmail.com>
2019-05-14global: regroup all importsJason A. Donenfeld
2019-04-18device: send: check packet length before freeing elementJason A. Donenfeld
2019-03-03global: begin modularizationJason A. Donenfeld