Update BatchTUN API for WireGuard

stack_mixed.go

@@ -145,15 +145,13 @@ func (m *Mixed) wintunLoop(winTun WinTun) {
 func (m *Mixed) batchLoop(linuxTUN BatchTUN, batchSize int) {
 	frontHeadroom := m.tun.FrontHeadroom()
 	packetBuffers := make([][]byte, batchSize)
-	readBuffers := make([][]byte, batchSize)
 	writeBuffers := make([][]byte, batchSize)
 	packetSizes := make([]int, batchSize)
 	for i := range packetBuffers {
-		packetBuffers[i] = make([]byte, m.mtu+frontHeadroom+PacketOffset)
-		readBuffers[i] = packetBuffers[i][frontHeadroom:]
+		packetBuffers[i] = make([]byte, m.mtu+frontHeadroom)
 	}
 	for {
-		n, err := linuxTUN.BatchRead(readBuffers, packetSizes)
+		n, err := linuxTUN.BatchRead(packetBuffers, frontHeadroom, packetSizes)
 		if err != nil {
 			if E.IsClosed(err) {
 				return
@@ -169,13 +167,13 @@ func (m *Mixed) batchLoop(linuxTUN BatchTUN, batchSize int) {
 				continue
 			}
 			packetBuffer := packetBuffers[i]
-			packet := packetBuffer[frontHeadroom+PacketOffset : frontHeadroom+packetSize]
+			packet := packetBuffer[frontHeadroom : frontHeadroom+packetSize]
 			if m.processPacket(packet) {
 				writeBuffers = append(writeBuffers, packetBuffer[:frontHeadroom+packetSize])
 			}
 		}
 		if len(writeBuffers) > 0 {
-			err = linuxTUN.BatchWrite(writeBuffers)
+			err = linuxTUN.BatchWrite(writeBuffers, frontHeadroom)
 			if err != nil {
 				m.logger.Trace(E.Cause(err, "batch write packet"))
 			}

stack_system.go

@@ -198,15 +198,13 @@ func (s *System) wintunLoop(winTun WinTun) {
 func (s *System) batchLoop(linuxTUN BatchTUN, batchSize int) {
 	frontHeadroom := s.tun.FrontHeadroom()
 	packetBuffers := make([][]byte, batchSize)
-	readBuffers := make([][]byte, batchSize)
 	writeBuffers := make([][]byte, batchSize)
 	packetSizes := make([]int, batchSize)
 	for i := range packetBuffers {
-		packetBuffers[i] = make([]byte, s.mtu+frontHeadroom+PacketOffset)
-		readBuffers[i] = packetBuffers[i][frontHeadroom:]
+		packetBuffers[i] = make([]byte, s.mtu+frontHeadroom)
 	}
 	for {
-		n, err := linuxTUN.BatchRead(readBuffers, packetSizes)
+		n, err := linuxTUN.BatchRead(packetBuffers, frontHeadroom, packetSizes)
 		if err != nil {
 			if E.IsClosed(err) {
 				return
@@ -222,13 +220,13 @@ func (s *System) batchLoop(linuxTUN BatchTUN, batchSize int) {
 				continue
 			}
 			packetBuffer := packetBuffers[i]
-			packet := packetBuffer[frontHeadroom+PacketOffset : frontHeadroom+packetSize]
+			packet := packetBuffer[frontHeadroom : frontHeadroom+packetSize]
 			if s.processPacket(packet) {
 				writeBuffers = append(writeBuffers, packetBuffer[:frontHeadroom+packetSize])
 			}
 		}
 		if len(writeBuffers) > 0 {
-			err = linuxTUN.BatchWrite(writeBuffers)
+			err = linuxTUN.BatchWrite(writeBuffers, frontHeadroom)
 			if err != nil {
 				s.logger.Trace(E.Cause(err, "batch write packet"))
 			}

tun.go

@@ -36,8 +36,8 @@ type WinTun interface {
 type BatchTUN interface {
 	Tun
 	BatchSize() int
-	BatchRead(buffers [][]byte, readN []int) (n int, err error)
-	BatchWrite(buffers [][]byte) error
+	BatchRead(buffers [][]byte, offset int, readN []int) (n int, err error)
+	BatchWrite(buffers [][]byte, offset int) error
 }
 
 type Options struct {

tun_linux.go

@@ -35,6 +35,8 @@ type NativeTun struct {
 	ruleIndex6        []int
 	gsoEnabled        bool
 	gsoBuffer         []byte
+	gsoToWrite        []int
+	gsoReadAccess     sync.Mutex
 	tcpGROAccess      sync.Mutex
 	tcp4GROTable      *tcpGROTable
 	tcp6GROTable      *tcpGROTable
@@ -105,7 +107,7 @@ func (t *NativeTun) Read(p []byte) (n int, err error) {
 
 func (t *NativeTun) Write(p []byte) (n int, err error) {
 	if t.gsoEnabled {
-		err = t.BatchWrite([][]byte{p})
+		err = t.BatchWrite([][]byte{p}, virtioNetHdrLen)
 		if err != nil {
 			return
 		}
@@ -140,37 +142,31 @@ func (t *NativeTun) BatchSize() int {
 	return batchSize
 }
 
-func (t *NativeTun) BatchRead(buffers [][]byte, readN []int) (n int, err error) {
-	if t.gsoEnabled {
-		n, err = t.tunFile.Read(t.gsoBuffer)
-		if err != nil {
-			return
-		}
-		n, err = handleVirtioRead(t.gsoBuffer[:n], buffers, readN, 0)
-		if err != nil {
-			return
-		}
-
+func (t *NativeTun) BatchRead(buffers [][]byte, offset int, readN []int) (n int, err error) {
+	t.gsoReadAccess.Lock()
+	defer t.gsoReadAccess.Unlock()
+	n, err = t.tunFile.Read(t.gsoBuffer)
+	if err != nil {
 		return
-	} else {
-		return 0, os.ErrInvalid
 	}
+	return handleVirtioRead(t.gsoBuffer[:n], buffers, readN, offset)
 }
 
-func (t *NativeTun) BatchWrite(buffers [][]byte) error {
+func (t *NativeTun) BatchWrite(buffers [][]byte, offset int) error {
 	t.tcpGROAccess.Lock()
 	defer func() {
 		t.tcp4GROTable.reset()
 		t.tcp6GROTable.reset()
 		t.tcpGROAccess.Unlock()
 	}()
-	var toWrite []int
-	err := handleGRO(buffers, virtioNetHdrLen, t.tcp4GROTable, t.tcp6GROTable, &toWrite)
+	t.gsoToWrite = t.gsoToWrite[:0]
+	err := handleGRO(buffers, offset, t.tcp4GROTable, t.tcp6GROTable, &t.gsoToWrite)
 	if err != nil {
 		return err
 	}
-	for _, bufferIndex := range toWrite {
-		_, err = t.tunFile.Write(buffers[bufferIndex])
+	offset -= virtioNetHdrLen
+	for _, bufferIndex := range t.gsoToWrite {
+		_, err = t.tunFile.Write(buffers[bufferIndex][offset:])
 		if err != nil {
 			return err
 		}

tun_linux_offload.go

@@ -750,8 +750,12 @@ func checksumNoFold(b []byte, initial uint64) uint64 {
 }
 
 func checksumFold(b []byte, initial uint64) uint16 {
-	r := clashtcpip.Checksum(uint32(initial), b)
-	return binary.BigEndian.Uint16(r[:])
+	ac := checksumNoFold(b, initial)
+	ac = (ac >> 16) + (ac & 0xffff)
+	ac = (ac >> 16) + (ac & 0xffff)
+	ac = (ac >> 16) + (ac & 0xffff)
+	ac = (ac >> 16) + (ac & 0xffff)
+	return uint16(ac)
 }
 
 func pseudoHeaderChecksumNoFold(protocol uint8, srcAddr, dstAddr []byte, totalLen uint16) uint64 {