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@jwhited jwhited commented May 29, 2025

5 commits in total. The first 2 are opportunistic, the latter 3 relating to handshake message allocs are also opportunistic, but also make certain aspects of the upcoming VXLAN/Geneve transport accounting simpler to land.

Only bother updating the rxBytes counter once we've processed a whole
vector, since additions are atomic.

cherry picked from commit WireGuard/wireguard-go@542e565

Updates tailscale/corp#28879

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
@jwhited jwhited requested a review from danderson May 29, 2025 17:25
basovnik and others added 4 commits May 29, 2025 10:35
There is a possible deadlock in `device.Close()` when you try to close
the device very soon after its start. The problem is that two different
methods acquire the same locks in different order:

1. device.Close()
 - device.ipcMutex.Lock()
 - device.state.Lock()

2. device.changeState(deviceState)
 - device.state.Lock()
 - device.ipcMutex.Lock()

Reproducer:

    func TestDevice_deadlock(t *testing.T) {
    	d := randDevice(t)
    	d.Close()
    }

Problem:

    $ go clean -testcache && go test -race -timeout 3s -run TestDevice_deadlock ./device | grep -A 10 sync.runtime_SemacquireMutex
    sync.runtime_SemacquireMutex(0xc000117d20?, 0x94?, 0x0?)
            /usr/local/opt/go/libexec/src/runtime/sema.go:77 +0x25
    sync.(*Mutex).lockSlow(0xc000130518)
            /usr/local/opt/go/libexec/src/sync/mutex.go:171 +0x213
    sync.(*Mutex).Lock(0xc000130518)
            /usr/local/opt/go/libexec/src/sync/mutex.go:90 +0x55
    golang.zx2c4.com/wireguard/device.(*Device).Close(0xc000130500)
            /Users/martin.basovnik/git/basovnik/wireguard-go/device/device.go:373 +0xb6
    golang.zx2c4.com/wireguard/device.TestDevice_deadlock(0x0?)
            /Users/martin.basovnik/git/basovnik/wireguard-go/device/device_test.go:480 +0x2c
    testing.tRunner(0xc00014c000, 0x131d7b0)
    --
    sync.runtime_SemacquireMutex(0xc000130564?, 0x60?, 0xc000130548?)
            /usr/local/opt/go/libexec/src/runtime/sema.go:77 +0x25
    sync.(*Mutex).lockSlow(0xc000130750)
            /usr/local/opt/go/libexec/src/sync/mutex.go:171 +0x213
    sync.(*Mutex).Lock(0xc000130750)
            /usr/local/opt/go/libexec/src/sync/mutex.go:90 +0x55
    sync.(*RWMutex).Lock(0xc000130750)
            /usr/local/opt/go/libexec/src/sync/rwmutex.go:147 +0x45
    golang.zx2c4.com/wireguard/device.(*Device).upLocked(0xc000130500)
            /Users/martin.basovnik/git/basovnik/wireguard-go/device/device.go:179 +0x72
    golang.zx2c4.com/wireguard/device.(*Device).changeState(0xc000130500, 0x1)

cherry picked from commit WireGuard/wireguard-go@12269c2

Updates tailscale/corp#28879

Signed-off-by: Martin Basovnik <martin.basovnik@gmail.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reduce allocations by eliminating byte reader, hand-rolled decoding and
reusing message structs.

Synthetic benchmark:

    var msgSink MessageInitiation
    func BenchmarkMessageInitiationUnmarshal(b *testing.B) {
        packet := make([]byte, MessageInitiationSize)
        reader := bytes.NewReader(packet)
        err := binary.Read(reader, binary.LittleEndian, &msgSink)
        if err != nil {
            b.Fatal(err)
        }
        b.Run("binary.Read", func(b *testing.B) {
            b.ReportAllocs()
            for range b.N {
                reader := bytes.NewReader(packet)
                _ = binary.Read(reader, binary.LittleEndian, &msgSink)
            }
        })
        b.Run("unmarshal", func(b *testing.B) {
            b.ReportAllocs()
            for range b.N {
                _ = msgSink.unmarshal(packet)
            }
        })
    }

Results:
                                         │      -      │
                                         │   sec/op    │
MessageInitiationUnmarshal/binary.Read-8   1.508µ ± 2%
MessageInitiationUnmarshal/unmarshal-8     12.66n ± 2%

                                         │      -       │
                                         │     B/op     │
MessageInitiationUnmarshal/binary.Read-8   208.0 ± 0%
MessageInitiationUnmarshal/unmarshal-8     0.000 ± 0%

                                         │      -       │
                                         │  allocs/op   │
MessageInitiationUnmarshal/binary.Read-8   2.000 ± 0%
MessageInitiationUnmarshal/unmarshal-8     0.000 ± 0%

cherry picked from commit WireGuard/wireguard-go@9e7529c

Updates tailscale/corp#28879

Signed-off-by: Alexander Yastrebov <yastrebov.alex@gmail.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This is already enforced in receive.go, but if these unmarshallers are
to have error return values anyway, make them as explicit as possible.

cherry picked from commit WireGuard/wireguard-go@842888a

Updates tailscale/corp#28879

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Optimize message encoding by eliminating binary.Write (which internally
uses reflection) in favour of hand-rolled encoding.

This is companion to 9e7529c.

Synthetic benchmark:

    var packetSink []byte
    func BenchmarkMessageInitiationMarshal(b *testing.B) {
        var msg MessageInitiation
        b.Run("binary.Write", func(b *testing.B) {
            b.ReportAllocs()
            for range b.N {
                var buf [MessageInitiationSize]byte
                writer := bytes.NewBuffer(buf[:0])
                _ = binary.Write(writer, binary.LittleEndian, msg)
                packetSink = writer.Bytes()
            }
        })
        b.Run("binary.Encode", func(b *testing.B) {
            b.ReportAllocs()
            for range b.N {
                packet := make([]byte, MessageInitiationSize)
                _, _ = binary.Encode(packet, binary.LittleEndian, msg)
                packetSink = packet
            }
        })
        b.Run("marshal", func(b *testing.B) {
            b.ReportAllocs()
            for range b.N {
                packet := make([]byte, MessageInitiationSize)
                _ = msg.marshal(packet)
                packetSink = packet
            }
        })
    }

Results:
                                             │      -      │
                                             │   sec/op    │
    MessageInitiationMarshal/binary.Write-8    1.337µ ± 0%
    MessageInitiationMarshal/binary.Encode-8   1.242µ ± 0%
    MessageInitiationMarshal/marshal-8         53.05n ± 1%

                                             │     -      │
                                             │    B/op    │
    MessageInitiationMarshal/binary.Write-8    368.0 ± 0%
    MessageInitiationMarshal/binary.Encode-8   160.0 ± 0%
    MessageInitiationMarshal/marshal-8         160.0 ± 0%

                                             │     -      │
                                             │ allocs/op  │
    MessageInitiationMarshal/binary.Write-8    3.000 ± 0%
    MessageInitiationMarshal/binary.Encode-8   1.000 ± 0%
    MessageInitiationMarshal/marshal-8         1.000 ± 0%

cherry picked from commit WireGuard/wireguard-go@264889f

Updates tailscale/corp#28879

Signed-off-by: Alexander Yastrebov <yastrebov.alex@gmail.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
@jwhited jwhited force-pushed the jwhited/upstream-cherry-picks branch from 83f6099 to c7e640d Compare May 29, 2025 17:36
@jwhited jwhited merged commit 0225465 into tailscale May 29, 2025
13 checks passed
@jwhited jwhited deleted the jwhited/upstream-cherry-picks branch May 29, 2025 17:43
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5 participants