tailscale: Add system interface support

protocol/tailscale/tun_device_windows.go

@@ -0,0 +1,117 @@
+//go:build windows
+
+package tailscale
+
+import (
+	"errors"
+	"os"
+	"sync"
+	"sync/atomic"
+
+	singTun "github.com/sagernet/sing-tun"
+	"github.com/sagernet/sing/common/logger"
+	wgTun "github.com/sagernet/wireguard-go/tun"
+)
+
+type tunDeviceAdapter struct {
+	tun       singTun.WinTun
+	nativeTun *singTun.NativeTun
+	events    chan wgTun.Event
+	mtu       atomic.Int64
+	closeOnce sync.Once
+}
+
+func newTunDeviceAdapter(tun singTun.Tun, mtu int, _ logger.ContextLogger) (wgTun.Device, error) {
+	winTun, ok := tun.(singTun.WinTun)
+	if !ok {
+		return nil, errors.New("not a windows tun device")
+	}
+	nativeTun, ok := winTun.(*singTun.NativeTun)
+	if !ok {
+		return nil, errors.New("unsupported windows tun device")
+	}
+	if mtu == 0 {
+		mtu = 1500
+	}
+	adapter := &tunDeviceAdapter{
+		tun:       winTun,
+		nativeTun: nativeTun,
+		events:    make(chan wgTun.Event, 1),
+	}
+	adapter.mtu.Store(int64(mtu))
+	adapter.events <- wgTun.EventUp
+	return adapter, nil
+}
+
+func (a *tunDeviceAdapter) File() *os.File {
+	return nil
+}
+
+func (a *tunDeviceAdapter) Read(bufs [][]byte, sizes []int, offset int) (count int, err error) {
+	packet, release, err := a.tun.ReadPacket()
+	if err != nil {
+		return 0, err
+	}
+	defer release()
+	sizes[0] = copy(bufs[0][offset-singTun.PacketOffset:], packet)
+	return 1, nil
+}
+
+func (a *tunDeviceAdapter) Write(bufs [][]byte, offset int) (count int, err error) {
+	for _, packet := range bufs {
+		if singTun.PacketOffset > 0 {
+			singTun.PacketFillHeader(packet[offset-singTun.PacketOffset:], singTun.PacketIPVersion(packet[offset:]))
+		}
+		_, err = a.tun.Write(packet[offset-singTun.PacketOffset:])
+		if err != nil {
+			return 0, err
+		}
+	}
+	return 0, nil
+}
+
+func (a *tunDeviceAdapter) MTU() (int, error) {
+	return int(a.mtu.Load()), nil
+}
+
+func (a *tunDeviceAdapter) ForceMTU(mtu int) {
+	if mtu <= 0 {
+		return
+	}
+	update := int(a.mtu.Load()) != mtu
+	a.mtu.Store(int64(mtu))
+	if update {
+		select {
+		case a.events <- wgTun.EventMTUUpdate:
+		default:
+		}
+	}
+}
+
+func (a *tunDeviceAdapter) LUID() uint64 {
+	if a.nativeTun == nil {
+		return 0
+	}
+	return a.nativeTun.LUID()
+}
+
+func (a *tunDeviceAdapter) Name() (string, error) {
+	return a.tun.Name()
+}
+
+func (a *tunDeviceAdapter) Events() <-chan wgTun.Event {
+	return a.events
+}
+
+func (a *tunDeviceAdapter) Close() error {
+	var err error
+	a.closeOnce.Do(func() {
+		close(a.events)
+		err = a.tun.Close()
+	})
+	return err
+}
+
+func (a *tunDeviceAdapter) BatchSize() int {
+	return 1
+}