Fix gvisor icmp write

Author: nekohasekai

ping/destination.go

@@ -69,10 +69,15 @@ func (d *Destination) loopRead() {
 	}
 }
 
-func (d *Destination) WritePacket(packet *buf.Buffer) error {
+func (d *Destination) WriteIP(packet *buf.Buffer) error {
 	return d.conn.WriteIP(packet)
 }
 
+func (d *Destination) WriteICMP(packet *buf.Buffer, sourceAddress netip.Addr) error {
+	d.conn.SetSourceAddress(sourceAddress)
+	return d.conn.WriteICMP(packet)
+}
+
 func (d *Destination) Close() error {
 	return d.conn.Close()
 }

ping/ping.go

@@ -194,8 +194,8 @@ func (c *Conn) WriteICMP(buffer *buf.Buffer) error {
 	return common.Error(c.conn.Write(buffer.Bytes()))
 }
 
-func (c *Conn) SetLocalAddr(addr netip.Addr) {
-	c.source.Store(addr)
+func (c *Conn) SetSourceAddress(address netip.Addr) {
+	c.source.Store(address)
 }
 
 func (c *Conn) SetReadDeadline(t time.Time) error {

ping/ping_test.go

@@ -85,7 +85,7 @@ func testPingIPv4ReadIP(t *testing.T, privileged bool, addr string) {
 	err = conn.WriteICMP(buf.As(request))
 	require.NoError(t, err)
 
-	conn.SetLocalAddr(netip.MustParseAddr("127.0.0.1"))
+	conn.SetSourceAddress(netip.MustParseAddr("127.0.0.1"))
 	require.NoError(t, conn.SetReadDeadline(time.Now().Add(3*time.Second)))
 
 	response := buf.NewPacket()
@@ -147,7 +147,7 @@ func testPingIPv6ReadIP(t *testing.T, privileged bool, addr string) {
 	err = conn.WriteICMP(buf.As(request))
 	require.NoError(t, err)
 
-	conn.SetLocalAddr(netip.MustParseAddr("::1"))
+	conn.SetSourceAddress(netip.MustParseAddr("::1"))
 	require.NoError(t, conn.SetReadDeadline(time.Now().Add(3*time.Second)))
 
 	response := buf.NewPacket()

route_nat.go

@@ -10,7 +10,8 @@ import (
 )
 
 type DirectRouteDestination interface {
-	WritePacket(packet *buf.Buffer) error
+	WriteIP(packet *buf.Buffer) error
+	WriteICMP(packet *buf.Buffer, source netip.Addr) error
 	Close() error
 }
 

stack_gvisor_icmp.go

@@ -16,6 +16,7 @@ import (
 	"github.com/sagernet/gvisor/pkg/tcpip/network/ipv4"
 	"github.com/sagernet/gvisor/pkg/tcpip/network/ipv6"
 	"github.com/sagernet/gvisor/pkg/tcpip/stack"
+	"github.com/sagernet/sing/common"
 	"github.com/sagernet/sing/common/buf"
 	M "github.com/sagernet/sing/common/metadata"
 	N "github.com/sagernet/sing/common/network"
@@ -227,5 +228,5 @@ func (w *ICMPBackWriter) WritePacket(p []byte) error {
 func icmpWritePacketBuffer(action DirectRouteDestination, packetBuffer *stack.PacketBuffer) error {
 	packetSlice := packetBuffer.TransportHeader().Slice()
 	packetSlice = append(packetSlice, packetBuffer.Data().AsRange().ToSlice()...)
-	return action.WritePacket(buf.As(packetSlice).ToOwned())
+	return action.WriteICMP(buf.As(packetSlice).ToOwned(), M.AddrFromIP(common.Ptr(packetBuffer.Network().SourceAddress()).AsSlice()))
 }

stack_system.go

@@ -670,7 +670,7 @@ func (s *System) processIPv4ICMP(ipHdr header.IPv4, icmpHdr header.ICMPv4) (bool
 			return false, nil
 		}
 		if action != nil {
-			return false, action.WritePacket(buf.As(ipHdr).ToOwned())
+			return false, action.WriteIP(buf.As(ipHdr).ToOwned())
 		}
 	}
 	icmpHdr.SetType(header.ICMPv4EchoReply)
@@ -741,7 +741,7 @@ func (s *System) processIPv6ICMP(ipHdr header.IPv6, icmpHdr header.ICMPv6) (bool
 			return false, nil
 		}
 		if action != nil {
-			return false, action.WritePacket(buf.As(ipHdr).ToOwned())
+			return false, action.WriteIP(buf.As(ipHdr).ToOwned())
 		}
 	}
 	icmpHdr.SetType(header.ICMPv6EchoReply)