Add handshake interface support for gVisor UDP

stack_gvisor.go

@@ -6,6 +6,7 @@ import (
 	"context"
 	"net/netip"
 	"time"
+	"unsafe"
 
 	"github.com/sagernet/gvisor/pkg/tcpip"
 	"github.com/sagernet/gvisor/pkg/tcpip/adapters/gonet"
@@ -70,44 +71,10 @@ func (t *GVisor) Start() error {
 	if err != nil {
 		return err
 	}
-	ipStack := stack.New(stack.Options{
-		NetworkProtocols: []stack.NetworkProtocolFactory{
-			ipv4.NewProtocol,
-			ipv6.NewProtocol,
-		},
-		TransportProtocols: []stack.TransportProtocolFactory{
-			tcp.NewProtocol,
-			udp.NewProtocol,
-			icmp.NewProtocol4,
-			icmp.NewProtocol6,
-		},
-	})
-	tErr := ipStack.CreateNIC(defaultNIC, linkEndpoint)
-	if tErr != nil {
-		return E.New("create nic: ", wrapStackError(tErr))
+	ipStack, err := newGVisorStack(linkEndpoint)
+	if err != nil {
+		return err
 	}
-	ipStack.SetRouteTable([]tcpip.Route{
-		{Destination: header.IPv4EmptySubnet, NIC: defaultNIC},
-		{Destination: header.IPv6EmptySubnet, NIC: defaultNIC},
-	})
-	ipStack.SetSpoofing(defaultNIC, true)
-	ipStack.SetPromiscuousMode(defaultNIC, true)
-	bufSize := 20 * 1024
-	ipStack.SetTransportProtocolOption(tcp.ProtocolNumber, &tcpip.TCPReceiveBufferSizeRangeOption{
-		Min:     1,
-		Default: bufSize,
-		Max:     bufSize,
-	})
-	ipStack.SetTransportProtocolOption(tcp.ProtocolNumber, &tcpip.TCPSendBufferSizeRangeOption{
-		Min:     1,
-		Default: bufSize,
-		Max:     bufSize,
-	})
-	sOpt := tcpip.TCPSACKEnabled(true)
-	ipStack.SetTransportProtocolOption(tcp.ProtocolNumber, &sOpt)
-	mOpt := tcpip.TCPModerateReceiveBufferOption(true)
-	ipStack.SetTransportProtocolOption(tcp.ProtocolNumber, &mOpt)
-
 	tcpForwarder := tcp.NewForwarder(ipStack, 0, 1024, func(r *tcp.ForwarderRequest) {
 		var wq waiter.Queue
 		handshakeCtx, cancel := context.WithCancel(context.Background())
@@ -162,11 +129,12 @@ func (t *GVisor) Start() error {
 				endpoint.Abort()
 				return
 			}
+			gConn := &gUDPConn{udpConn, ipStack, (*gRequest)(unsafe.Pointer(request)).pkt.IncRef()}
 			go func() {
 				var metadata M.Metadata
 				metadata.Source = M.SocksaddrFromNet(lAddr)
 				metadata.Destination = M.SocksaddrFromNet(rAddr)
-				ctx, conn := canceler.NewPacketConn(t.ctx, bufio.NewPacketConn(&bufio.UnbindPacketConn{ExtendedConn: bufio.NewExtendedConn(&gUDPConn{udpConn}), Addr: M.SocksaddrFromNet(rAddr)}), time.Duration(t.udpTimeout)*time.Second)
+				ctx, conn := canceler.NewPacketConn(t.ctx, bufio.NewPacketConn(&bufio.UnbindPacketConn{ExtendedConn: bufio.NewExtendedConn(gConn), Addr: M.SocksaddrFromNet(rAddr)}), time.Duration(t.udpTimeout)*time.Second)
 				hErr := t.handler.NewPacketConnection(ctx, conn, metadata)
 				if hErr != nil {
 					endpoint.Abort()
@@ -207,3 +175,44 @@ func AddrFromAddress(address tcpip.Address) netip.Addr {
 		return netip.AddrFrom4(address.As4())
 	}
 }
+
+func newGVisorStack(ep stack.LinkEndpoint) (*stack.Stack, error) {
+	ipStack := stack.New(stack.Options{
+		NetworkProtocols: []stack.NetworkProtocolFactory{
+			ipv4.NewProtocol,
+			ipv6.NewProtocol,
+		},
+		TransportProtocols: []stack.TransportProtocolFactory{
+			tcp.NewProtocol,
+			udp.NewProtocol,
+			icmp.NewProtocol4,
+			icmp.NewProtocol6,
+		},
+	})
+	tErr := ipStack.CreateNIC(defaultNIC, ep)
+	if tErr != nil {
+		return nil, E.New("create nic: ", wrapStackError(tErr))
+	}
+	ipStack.SetRouteTable([]tcpip.Route{
+		{Destination: header.IPv4EmptySubnet, NIC: defaultNIC},
+		{Destination: header.IPv6EmptySubnet, NIC: defaultNIC},
+	})
+	ipStack.SetSpoofing(defaultNIC, true)
+	ipStack.SetPromiscuousMode(defaultNIC, true)
+	bufSize := 20 * 1024
+	ipStack.SetTransportProtocolOption(tcp.ProtocolNumber, &tcpip.TCPReceiveBufferSizeRangeOption{
+		Min:     1,
+		Default: bufSize,
+		Max:     bufSize,
+	})
+	ipStack.SetTransportProtocolOption(tcp.ProtocolNumber, &tcpip.TCPSendBufferSizeRangeOption{
+		Min:     1,
+		Default: bufSize,
+		Max:     bufSize,
+	})
+	sOpt := tcpip.TCPSACKEnabled(true)
+	ipStack.SetTransportProtocolOption(tcp.ProtocolNumber, &sOpt)
+	mOpt := tcpip.TCPModerateReceiveBufferOption(true)
+	ipStack.SetTransportProtocolOption(tcp.ProtocolNumber, &mOpt)
+	return ipStack, nil
+}

stack_gvisor_err.go

@@ -27,28 +27,6 @@ func (c *gTCPConn) Write(b []byte) (n int, err error) {
 	return
 }
 
-type gUDPConn struct {
-	*gonet.UDPConn
-}
-
-func (c *gUDPConn) Read(b []byte) (n int, err error) {
-	n, err = c.UDPConn.Read(b)
-	if err == nil {
-		return
-	}
-	err = wrapError(err)
-	return
-}
-
-func (c *gUDPConn) Write(b []byte) (n int, err error) {
-	n, err = c.UDPConn.Write(b)
-	if err == nil {
-		return
-	}
-	err = wrapError(err)
-	return
-}
-
 func wrapStackError(err tcpip.Error) error {
 	switch err.(type) {
 	case *tcpip.ErrClosedForSend,

stack_gvisor_udp.go

@@ -4,11 +4,15 @@ package tun
 
 import (
 	"context"
+	"errors"
 	"math"
 	"net/netip"
+	"os"
+	"syscall"
 
 	"github.com/sagernet/gvisor/pkg/buffer"
 	"github.com/sagernet/gvisor/pkg/tcpip"
+	"github.com/sagernet/gvisor/pkg/tcpip/adapters/gonet"
 	"github.com/sagernet/gvisor/pkg/tcpip/checksum"
 	"github.com/sagernet/gvisor/pkg/tcpip/header"
 	"github.com/sagernet/gvisor/pkg/tcpip/stack"
@@ -78,6 +82,7 @@ type UDPBackWriter struct {
 	source        tcpip.Address
 	sourcePort    uint16
 	sourceNetwork tcpip.NetworkProtocolNumber
+	packet        stack.PacketBufferPtr
 }
 
 func (w *UDPBackWriter) WritePacket(packetBuffer *buf.Buffer, destination M.Socksaddr) error {
@@ -141,3 +146,98 @@ func (w *UDPBackWriter) WritePacket(packetBuffer *buf.Buffer, destination M.Sock
 	route.Stats().UDP.PacketsSent.Increment()
 	return nil
 }
+
+func (w *UDPBackWriter) HandshakeFailure(err error) error {
+	if w.packet == nil {
+		return os.ErrClosed
+	}
+	err = gWriteUnreachable(w.stack, w.packet, err)
+	w.packet.DecRef()
+	w.packet = nil
+	return err
+}
+
+type gRequest struct {
+	stack *stack.Stack
+	id    stack.TransportEndpointID
+	pkt   stack.PacketBufferPtr
+}
+
+type gUDPConn struct {
+	*gonet.UDPConn
+	stack  *stack.Stack
+	packet stack.PacketBufferPtr
+}
+
+func (c *gUDPConn) Read(b []byte) (n int, err error) {
+	n, err = c.UDPConn.Read(b)
+	if err == nil {
+		return
+	}
+	err = wrapError(err)
+	return
+}
+
+func (c *gUDPConn) Write(b []byte) (n int, err error) {
+	n, err = c.UDPConn.Write(b)
+	if err == nil {
+		return
+	}
+	err = wrapError(err)
+	return
+}
+
+func (c *gUDPConn) Close() error {
+	c.packet.DecRef()
+	c.packet = nil
+	return c.UDPConn.Close()
+}
+
+func (c *gUDPConn) HandshakeFailure(err error) error {
+	if c.packet == nil {
+		return os.ErrClosed
+	}
+	err = gWriteUnreachable(c.stack, c.packet, err)
+	c.packet.DecRef()
+	c.packet = nil
+	return err
+}
+
+func gWriteUnreachable(gStack *stack.Stack, packet stack.PacketBufferPtr, err error) error {
+	if errors.Is(err, syscall.ENETUNREACH) {
+		if packet.NetworkProtocolNumber == header.IPv4ProtocolNumber {
+			return gWriteUnreachable4(gStack, packet, stack.RejectIPv4WithICMPNetUnreachable)
+		} else {
+			return gWriteUnreachable6(gStack, packet, stack.RejectIPv6WithICMPNoRoute)
+		}
+	} else if errors.Is(err, syscall.EHOSTUNREACH) {
+		if packet.NetworkProtocolNumber == header.IPv4ProtocolNumber {
+			return gWriteUnreachable4(gStack, packet, stack.RejectIPv4WithICMPHostUnreachable)
+		} else {
+			return gWriteUnreachable6(gStack, packet, stack.RejectIPv6WithICMPNoRoute)
+		}
+	} else if errors.Is(err, syscall.ECONNREFUSED) {
+		if packet.NetworkProtocolNumber == header.IPv4ProtocolNumber {
+			return gWriteUnreachable4(gStack, packet, stack.RejectIPv4WithICMPPortUnreachable)
+		} else {
+			return gWriteUnreachable6(gStack, packet, stack.RejectIPv6WithICMPPortUnreachable)
+		}
+	}
+	return nil
+}
+
+func gWriteUnreachable4(gStack *stack.Stack, packet stack.PacketBufferPtr, icmpCode stack.RejectIPv4WithICMPType) error {
+	err := gStack.NetworkProtocolInstance(header.IPv4ProtocolNumber).(stack.RejectIPv4WithHandler).SendRejectionError(packet, icmpCode, true)
+	if err != nil {
+		return wrapStackError(err)
+	}
+	return nil
+}
+
+func gWriteUnreachable6(gStack *stack.Stack, packet stack.PacketBufferPtr, icmpCode stack.RejectIPv6WithICMPType) error {
+	err := gStack.NetworkProtocolInstance(header.IPv6ProtocolNumber).(stack.RejectIPv6WithHandler).SendRejectionError(packet, icmpCode, true)
+	if err != nil {
+		return wrapStackError(err)
+	}
+	return nil
+}

stack_system.go

@@ -91,6 +91,15 @@ func (s *System) Close() error {
 }
 
 func (s *System) Start() error {
+	err := s.start()
+	if err != nil {
+		return err
+	}
+	go s.tunLoop()
+	return nil
+}
+
+func (s *System) start() error {
 	err := fixWindowsFirewall()
 	if err != nil {
 		return E.Cause(err, "fix windows firewall for system stack")
@@ -125,7 +134,6 @@ func (s *System) Start() error {
 	}
 	s.tcpNat = NewNat(s.ctx, time.Second*time.Duration(s.udpTimeout))
 	s.udpNat = udpnat.New[netip.AddrPort](s.udpTimeout, s.handler)
-	go s.tunLoop()
 	return nil
 }