fix: let quic-go works on outbound's packetConn

adapter/outbound/base.go

@@ -210,6 +210,8 @@ func NewConn(c net.Conn, a C.ProxyAdapter) C.Conn {
 type packetConn struct {
 	net.PacketConn
 	chain                   C.Chain
+	adapterName             string
+	connID                  string
 	actualRemoteDestination string
 }
 
@@ -227,8 +229,14 @@ func (c *packetConn) AppendToChains(a C.ProxyAdapter) {
 	c.chain = append(c.chain, a.Name())
 }
 
+func (c *packetConn) LocalAddr() net.Addr {
+	lAddr := c.PacketConn.LocalAddr()
+	return N.NewCustomAddr(c.adapterName, c.connID, lAddr) // make quic-go's connMultiplexer happy
+}
+
 func newPacketConn(pc net.PacketConn, a C.ProxyAdapter) C.PacketConn {
-	return &packetConn{pc, []string{a.Name()}, parseRemoteDestination(a.Addr())}
+	id, _ := utils.UnsafeUUIDGenerator.NewV4()
+	return &packetConn{pc, []string{a.Name()}, a.Name(), id.String(), parseRemoteDestination(a.Addr())}
 }
 
 func parseRemoteDestination(addr string) string {

common/net/addr.go

@@ -0,0 +1,36 @@
+package net
+
+import (
+	"net"
+)
+
+type CustomAddr interface {
+	net.Addr
+	RawAddr() net.Addr
+}
+
+type customAddr struct {
+	networkStr string
+	addrStr    string
+	rawAddr    net.Addr
+}
+
+func (a customAddr) Network() string {
+	return a.networkStr
+}
+
+func (a customAddr) String() string {
+	return a.addrStr
+}
+
+func (a customAddr) RawAddr() net.Addr {
+	return a.rawAddr
+}
+
+func NewCustomAddr(networkStr string, addrStr string, rawAddr net.Addr) CustomAddr {
+	return customAddr{
+		networkStr: networkStr,
+		addrStr:    addrStr,
+		rawAddr:    rawAddr,
+	}
+}

transport/tuic/conn.go

@@ -250,29 +250,7 @@ func (q *quicStreamPacketConn) WriteTo(p []byte, addr net.Addr) (n int, err erro
 }
 
 func (q *quicStreamPacketConn) LocalAddr() net.Addr {
-	addr := q.quicConn.LocalAddr()
+	return q.quicConn.LocalAddr()
-	if q.inputConn != nil { // client
-		return &packetAddr{addrStr: q.quicConn.LocalAddr().String(), connId: q.connId, rawAddr: addr}
-	}
-	return addr // server
 }
 
 var _ net.PacketConn = &quicStreamPacketConn{}
-
-type packetAddr struct {
-	addrStr string
-	connId  uint32
-	rawAddr net.Addr
-}
-
-func (a packetAddr) Network() string {
-	return "tuic"
-}
-
-func (a packetAddr) String() string {
-	return fmt.Sprintf("%s-%d", a.addrStr, a.connId)
-}
-
-func (a packetAddr) RawAddr() net.Addr {
-	return a.rawAddr
-}

transport/tuic/server.go

@@ -5,6 +5,7 @@ import (
 	"bytes"
 	"context"
 	"crypto/tls"
+	"fmt"
 	"net"
 	"sync"
 	"sync/atomic"
@@ -153,7 +154,7 @@ func (s *serverHandler) parsePacket(packet Packet, udpRelayMode string) (err err
 	return s.HandleUdpFn(packet.ADDR.SocksAddr(), &serverUDPPacket{
 		pc:     pc,
 		packet: &packet,
-		rAddr:  &packetAddr{addrStr: "tuic-" + s.uuid.String(), connId: assocId, rawAddr: s.quicConn.RemoteAddr()},
+		rAddr:  N.NewCustomAddr("tuic", fmt.Sprintf("tuic-%s-%d", s.uuid, assocId), s.quicConn.RemoteAddr()), // for tunnel's handleUDPConn
 	})
 }