We missed a function exit point. This was exacerbated by e3134bf
("device: defer state machine transitions until configuration is
complete"), but the bug existed prior. Minus provided the following
useful reproducer script:
#!/usr/bin/env bash
set -eux
make wireguard-go || exit 125
ip netns del test-ns || true
ip netns add test-ns
ip link add test-kernel type wireguard
wg set test-kernel listen-port 0 private-key <(echo "QMCfZcp1KU27kEkpcMCgASEjDnDZDYsfMLHPed7+538=") peer "eDPZJMdfnb8ZcA/VSUnLZvLB2k8HVH12ufCGa7Z7rHI=" allowed-ips 10.51.234.10/32
ip link set test-kernel netns test-ns up
ip -n test-ns addr add 10.51.234.1/24 dev test-kernel
port=$(ip netns exec test-ns wg show test-kernel listen-port)
ip link del test-go || true
./wireguard-go test-go
wg set test-go private-key <(echo "WBM7qimR3vFk1QtWNfH+F4ggy/hmO+5hfIHKxxI4nF4=") peer "+nj9Dkqpl4phsHo2dQliGm5aEiWJJgBtYKbh7XjeNjg=" allowed-ips 0.0.0.0/0 endpoint 127.0.0.1:$port
ip addr add 10.51.234.10/24 dev test-go
ip link set test-go up
ping -c2 -W1 10.51.234.1
Reported-by: minus <minus@mnus.de>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
The deferred RUnlock calls weren't executing until all peers
had been processed. Add an anonymous function so that each
peer may be unlocked as soon as it is completed.
Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
There are more places where we'll need to add it later, when Go 1.18
comes out with support for it in the "net" package. Also, allowedips
still uses slices internally, which might be suboptimal.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
A peer.endpoint never becomes nil after being not-nil, so creation is
the only time we actually need to set this. This prevents a race from
when the variable is actually used elsewhere, and allows us to avoid an
expensive atomic.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
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>
benchmark old ns/op new ns/op delta
BenchmarkUAPIGet-16 2872 2157 -24.90%
benchmark old allocs new allocs delta
BenchmarkUAPIGet-16 30 18 -40.00%
benchmark old bytes new bytes delta
BenchmarkUAPIGet-16 737 256 -65.26%
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
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>
This makes the IpcGet method much faster.
We also refactor the traversal API to use a callback so that we don't
need to allocate at all. Avoiding allocations we do self-masking on
insertion, which in turn means that split intermediate nodes require a
copy of the bits.
benchmark old ns/op new ns/op delta
BenchmarkUAPIGet-16 3243 2659 -18.01%
benchmark old allocs new allocs delta
BenchmarkUAPIGet-16 35 30 -14.29%
benchmark old bytes new bytes delta
BenchmarkUAPIGet-16 1218 737 -39.49%
This benchmark is good, though it's only for a pair of peers, each with
only one allowedips. As this grows, the delta expands considerably.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
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>
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>
The declaration of err in
nextByte, err := buffered.ReadByte
shadows the declaration of err in
op, err := buffered.ReadString('\n')
above. As a result, the assignments to err in
err = ipcErrorf(ipc.IpcErrorInvalid, "trailing character in UAPI get: %c", nextByte)
and in
err = device.IpcGetOperation(buffered.Writer)
do not modify the correct err variable.
Found by staticcheck.
Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
Plenty more to go, but a start:
name old time/op new time/op delta
UAPIGet-4 6.37µs ± 2% 5.56µs ± 1% -12.70% (p=0.000 n=8+8)
name old alloc/op new alloc/op delta
UAPIGet-4 1.98kB ± 0% 1.22kB ± 0% -38.71% (p=0.000 n=10+10)
name old allocs/op new allocs/op delta
UAPIGet-4 42.0 ± 0% 35.0 ± 0% -16.67% (p=0.000 n=10+10)
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Unify the handling of unexpected UAPI errors.
The comment that says "should never happen" is incorrect;
this could happen due to I/O errors. Correct it.
Change error message capitalization for consistency.
Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
The goal of this change is to make the structure
of IpcSetOperation easier to follow.
IpcSetOperation contains a small state machine:
It starts by configuring the device,
then shifts to configuring one peer at a time.
Having the code all in one giant method obscured that structure.
Split out the parts into helper functions and encapsulate the peer state.
This makes the overall structure more apparent.
Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
Expand IPCError to contain a wrapped error,
and add a helper to make constructing such errors easier.
Add a defer-based "log on returned error" to IpcSetOperation.
This lets us simplify all of the error return paths.
Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
bufio is not required.
strings.Builder is cheaper than bytes.Buffer for constructing strings.
io.Writer is more flexible than io.StringWriter,
and just as cheap (when used with io.WriteString).
Run gofmt.
Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
Any io.Reader will do, and there are no performance concerns here.
This is technically backwards incompatible,
but it is very unlikely to break any existing code.
It is compatible with the existing uses in wireguard-{windows,android,apple}
and also will allow us to slightly simplify it if desired.
Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
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>
