Commit graph

12 commits

Author SHA1 Message Date
Josh Bleecher Snyder 15810daa22 device: separate timersInit from timersStart
timersInit sets up the timers.
It need only be done once per peer.

timersStart does the work to prepare the timers
for a newly running peer. It needs to be done
every time a peer starts.

Separate the two and call them in the appropriate places.
This prevents data races on the peer's timers fields
when starting and stopping peers.

Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
2021-02-08 10:32:07 -08:00
Josh Bleecher Snyder 0bcb822e5b device: overhaul device state management
This commit simplifies device state management.
It creates a single unified state variable and documents its semantics.

It also makes state changes more atomic.
As an example of the sort of bug that occurred due to non-atomic state changes,
the following sequence of events used to occur approximately every 2.5 million test runs:

* RoutineTUNEventReader received an EventDown event.
* It called device.Down, which called device.setUpDown.
* That set device.state.changing, but did not yet attempt to lock device.state.Mutex.
* Test completion called device.Close.
* device.Close locked device.state.Mutex.
* device.Close blocked on a call to device.state.stopping.Wait.
* device.setUpDown then attempted to lock device.state.Mutex and blocked.

Deadlock results. setUpDown cannot progress because device.state.Mutex is locked.
Until setUpDown returns, RoutineTUNEventReader cannot call device.state.stopping.Done.
Until device.state.stopping.Done gets called, device.state.stopping.Wait is blocked.
As long as device.state.stopping.Wait is blocked, device.state.Mutex cannot be unlocked.
This commit fixes that deadlock by holding device.state.mu
when checking that the device is not closed.

Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
2021-02-08 10:32:07 -08:00
Jason A. Donenfeld d4112d9096 global: bump copyright
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2021-01-28 17:52:15 +01:00
Jason A. Donenfeld 1b092ce584 device: get rid of nonce routine
This moves to a simple queue with no routine processing it, to reduce
scheduler pressure.

This splits latency in half!

benchmark                  old ns/op     new ns/op     delta
BenchmarkThroughput-16     2394          2364          -1.25%
BenchmarkLatency-16        259652        120810        -53.47%

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2021-01-27 18:38:27 +01:00
Jason A. Donenfeld d669c78c43 device: combine debug and info log levels into 'verbose'
There are very few cases, if any, in which a user only wants one of
these levels, so combine it into a single level.

While we're at it, reduce indirection on the loggers by using an empty
function rather than a nil function pointer. It's not like we have
retpolines anyway, and we were always calling through a function with a
branch prior, so this seems like a net gain.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2021-01-26 23:05:48 +01:00
Josh Bleecher Snyder 7139279cd0 device: change logging interface to use functions
This commit overhauls wireguard-go's logging.

The primary, motivating change is to use a function instead
of a *log.Logger as the basic unit of logging.
Using functions provides a lot more flexibility for
people to bring their own logging system.

It also introduces logging helper methods on Device.
These reduce line noise at the call site.
They also allow for log functions to be nil;
when nil, instead of generating a log line and throwing it away,
we don't bother generating it at all.
This spares allocation and pointless work.

This is a breaking change, although the fix required
of clients is fairly straightforward.

Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
2021-01-26 22:40:20 +01:00
Josh Bleecher Snyder f7bbdc31a0 device: fix data race in peer.timersActive
Found by the race detector and existing tests.

To avoid introducing a lock into this hot path,
calculate and cache whether any peers exist.

Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
2021-01-07 14:49:44 +01:00
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 ea8fbb5927 device: use defer to simplify peer.NewTimer
This also makes the lifetime of modifyingLock more prominent.

Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
2021-01-07 14:49:44 +01:00
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
Jason A. Donenfeld f70546bc2e device: timers: add jitter on ack failure reinitiation 2019-05-24 13:48:25 +02:00
Jason A. Donenfeld 69f0fe67b6 global: begin modularization 2019-03-03 05:00:40 +01:00
Renamed from timers.go (Browse further)