Use connect for quic/dns udp connections

outbound/default.go

@@ -68,6 +68,10 @@ func NewEarlyConnection(ctx context.Context, this N.Dialer, conn net.Conn, metad
 }
 
 func NewPacketConnection(ctx context.Context, this N.Dialer, conn N.PacketConn, metadata adapter.InboundContext) error {
+	switch metadata.Protocol {
+	case C.ProtocolQUIC, C.ProtocolDNS:
+		return connectPacketConnection(ctx, this, conn, metadata)
+	}
 	ctx = adapter.WithContext(ctx, &metadata)
 	var outConn net.PacketConn
 	var err error
@@ -92,6 +96,31 @@ func NewPacketConnection(ctx context.Context, this N.Dialer, conn N.PacketConn,
 	return bufio.CopyPacketConn(ctx, conn, bufio.NewPacketConn(outConn))
 }
 
+func connectPacketConnection(ctx context.Context, this N.Dialer, conn N.PacketConn, metadata adapter.InboundContext) error {
+	ctx = adapter.WithContext(ctx, &metadata)
+	var outConn net.Conn
+	var err error
+	if len(metadata.DestinationAddresses) > 0 {
+		outConn, err = N.DialSerial(ctx, this, N.NetworkTCP, metadata.Destination, metadata.DestinationAddresses)
+	} else {
+		outConn, err = this.DialContext(ctx, N.NetworkTCP, metadata.Destination)
+	}
+	if err != nil {
+		return N.HandshakeFailure(conn, err)
+	}
+	if metadata.Protocol != "" {
+		switch metadata.Protocol {
+		case C.ProtocolQUIC:
+			ctx, conn = canceler.NewPacketConn(ctx, conn, C.QUICTimeout)
+		case C.ProtocolDNS:
+			ctx, conn = canceler.NewPacketConn(ctx, conn, C.DNSTimeout)
+		case C.ProtocolSTUN:
+			ctx, conn = canceler.NewPacketConn(ctx, conn, C.STUNTimeout)
+		}
+	}
+	return bufio.CopyPacketConn(ctx, conn, bufio.NewUnbindPacketConn(outConn))
+}
+
 func CopyEarlyConn(ctx context.Context, conn net.Conn, serverConn net.Conn) error {
 	if cachedReader, isCached := serverConn.(N.CachedReader); isCached {
 		payload := cachedReader.ReadCached()