Add GSO support

stack.go

@@ -19,10 +19,7 @@ type Stack interface {
 type StackOptions struct {
 	Context                context.Context
 	Tun                    Tun
-	Name                   string
-	MTU                    uint32
-	Inet4Address           []netip.Prefix
-	Inet6Address           []netip.Prefix
+	TunOptions             Options
 	EndpointIndependentNat bool
 	UDPTimeout             int64
 	Handler                Handler
@@ -31,13 +28,21 @@ type StackOptions struct {
 	InterfaceFinder        control.InterfaceFinder
 }
 
+func (o *StackOptions) BufferSize() uint32 {
+	if o.TunOptions.GSO {
+		return o.TunOptions.GSOMaxSize
+	} else {
+		return o.TunOptions.MTU
+	}
+}
+
 func NewStack(
 	stack string,
 	options StackOptions,
 ) (Stack, error) {
 	switch stack {
 	case "":
-		if WithGVisor {
+		if WithGVisor && !options.TunOptions.GSO {
 			return NewMixed(options)
 		} else {
 			return NewSystem(options)
@@ -48,8 +53,6 @@ func NewStack(
 		return NewMixed(options)
 	case "system":
 		return NewSystem(options)
-	case "lwip":
-		return NewLWIP(options)
 	default:
 		return nil, E.New("unknown stack: ", stack)
 	}

stack_gvisor.go

@@ -31,7 +31,6 @@ const defaultNIC tcpip.NICID = 1
 type GVisor struct {
 	ctx                    context.Context
 	tun                    GVisorTun
-	tunMtu                 uint32
 	endpointIndependentNat bool
 	udpTimeout             int64
 	broadcastAddr          netip.Addr
@@ -57,10 +56,9 @@ func NewGVisor(
 	gStack := &GVisor{
 		ctx:                    options.Context,
 		tun:                    gTun,
-		tunMtu:                 options.MTU,
 		endpointIndependentNat: options.EndpointIndependentNat,
 		udpTimeout:             options.UDPTimeout,
-		broadcastAddr:          BroadcastAddr(options.Inet4Address),
+		broadcastAddr:          BroadcastAddr(options.TunOptions.Inet4Address),
 		handler:                options.Handler,
 		logger:                 options.Logger,
 	}
@@ -72,7 +70,7 @@ func (t *GVisor) Start() error {
 	if err != nil {
 		return err
 	}
-	linkEndpoint = &LinkEndpointFilter{linkEndpoint, t.broadcastAddr, t.tun.CreateVectorisedWriter()}
+	linkEndpoint = &LinkEndpointFilter{linkEndpoint, t.broadcastAddr, bufio.NewVectorisedWriter(t.tun)}
 	ipStack, err := newGVisorStack(linkEndpoint)
 	if err != nil {
 		return err

stack_mixed.go

@@ -38,7 +38,7 @@ func NewMixed(
 	}
 	return &Mixed{
 		System:                 system.(*System),
-		writer:                 options.Tun.CreateVectorisedWriter(),
+		writer:                 bufio.NewVectorisedWriter(options.Tun),
 		endpointIndependentNat: options.EndpointIndependentNat,
 	}, nil
 }
@@ -95,7 +95,7 @@ func (m *Mixed) tunLoop() {
 		m.wintunLoop(winTun)
 		return
 	}
-	packetBuffer := make([]byte, m.mtu+PacketOffset)
+	packetBuffer := make([]byte, m.bufferSize+m.tun.FrontHeadroom())
 	for {
 		n, err := m.tun.Read(packetBuffer)
 		if err != nil {
@@ -104,12 +104,13 @@ func (m *Mixed) tunLoop() {
 		if n < clashtcpip.IPv4PacketMinLength {
 			continue
 		}
-		packet := packetBuffer[PacketOffset:n]
+		rawPacket := packetBuffer[:n]
+		packet := packetBuffer[m.tun.FrontHeadroom():n]
 		switch ipVersion := packet[0] >> 4; ipVersion {
 		case 4:
-			err = m.processIPv4(packet)
+			err = m.processIPv4(rawPacket, packet)
 		case 6:
-			err = m.processIPv6(packet)
+			err = m.processIPv6(rawPacket, packet)
 		default:
 			err = E.New("ip: unknown version: ", ipVersion)
 		}
@@ -131,9 +132,9 @@ func (m *Mixed) wintunLoop(winTun WinTun) {
 		}
 		switch ipVersion := packet[0] >> 4; ipVersion {
 		case 4:
-			err = m.processIPv4(packet)
+			err = m.processIPv4(packet, packet)
 		case 6:
-			err = m.processIPv6(packet)
+			err = m.processIPv6(packet, packet)
 		default:
 			err = E.New("ip: unknown version: ", ipVersion)
 		}
@@ -144,14 +145,14 @@ func (m *Mixed) wintunLoop(winTun WinTun) {
 	}
 }
 
-func (m *Mixed) processIPv4(packet clashtcpip.IPv4Packet) error {
+func (m *Mixed) processIPv4(rawPacket []byte, packet clashtcpip.IPv4Packet) error {
 	destination := packet.DestinationIP()
 	if destination == m.broadcastAddr || !destination.IsGlobalUnicast() {
 		return common.Error(m.tun.Write(packet))
 	}
 	switch packet.Protocol() {
 	case clashtcpip.TCP:
-		return m.processIPv4TCP(packet, packet.Payload())
+		return m.processIPv4TCP(rawPacket, packet, packet.Payload())
 	case clashtcpip.UDP:
 		pkt := stack.NewPacketBuffer(stack.PacketBufferOptions{
 			Payload: buffer.MakeWithData(packet),
@@ -160,19 +161,19 @@ func (m *Mixed) processIPv4(packet clashtcpip.IPv4Packet) error {
 		pkt.DecRef()
 		return nil
 	case clashtcpip.ICMP:
-		return m.processIPv4ICMP(packet, packet.Payload())
+		return m.processIPv4ICMP(rawPacket, packet, packet.Payload())
 	default:
 		return common.Error(m.tun.Write(packet))
 	}
 }
 
-func (m *Mixed) processIPv6(packet clashtcpip.IPv6Packet) error {
+func (m *Mixed) processIPv6(rawPacket []byte, packet clashtcpip.IPv6Packet) error {
 	if !packet.DestinationIP().IsGlobalUnicast() {
 		return common.Error(m.tun.Write(packet))
 	}
 	switch packet.Protocol() {
 	case clashtcpip.TCP:
-		return m.processIPv6TCP(packet, packet.Payload())
+		return m.processIPv6TCP(rawPacket, packet, packet.Payload())
 	case clashtcpip.UDP:
 		pkt := stack.NewPacketBuffer(stack.PacketBufferOptions{
 			Payload: buffer.MakeWithData(packet),
@@ -181,7 +182,7 @@ func (m *Mixed) processIPv6(packet clashtcpip.IPv6Packet) error {
 		pkt.DecRef()
 		return nil
 	case clashtcpip.ICMPv6:
-		return m.processIPv6ICMP(packet, packet.Payload())
+		return m.processIPv6ICMP(rawPacket, packet, packet.Payload())
 	default:
 		return common.Error(m.tun.Write(packet))
 	}