chore: support relay native udp when using ss and ssr protocol

adapter/outbound/base.go

@@ -62,6 +62,16 @@ func (b *Base) ListenPacketContext(ctx context.Context, metadata *C.Metadata, op
 	return nil, errors.New("no support")
 }
 
+// ListenPacketOnPacketConn implements C.ProxyAdapter
+func (b *Base) ListenPacketOnPacketConn(ctx context.Context, c C.PacketConn, metadata *C.Metadata) (C.PacketConn, error) {
+	return nil, errors.New("no support")
+}
+
+// SupportLPPC implements C.ProxyAdapter
+func (b *Base) SupportLPPC() bool {
+	return false
+}
+
 // ListenPacketOnStreamConn implements C.ProxyAdapter
 func (b *Base) ListenPacketOnStreamConn(c net.Conn, metadata *C.Metadata) (_ C.PacketConn, err error) {
 	return nil, errors.New("no support")

adapter/outbound/shadowsocks.go

@@ -120,6 +120,22 @@ func (ss *ShadowSocks) ListenPacketContext(ctx context.Context, metadata *C.Meta
 	return newPacketConn(pc, ss), nil
 }
 
+// ListenPacketOnPacketConn implements C.ProxyAdapter
+func (ss *ShadowSocks) ListenPacketOnPacketConn(ctx context.Context, c C.PacketConn, metadata *C.Metadata) (_ C.PacketConn, err error) {
+	addr, err := resolveUDPAddrWithPrefer(ctx, "udp", ss.addr, ss.prefer)
+	if err != nil {
+		return nil, err
+	}
+
+	pc := ss.method.DialPacketConn(&bufio.BindPacketConn{PacketConn: c, Addr: addr})
+	return newPacketConn(pc, ss), nil
+}
+
+// SupportLPPC implements C.ProxyAdapter
+func (ss *ShadowSocks) SupportLPPC() bool {
+	return true
+}
+
 // ListenPacketOnStreamConn implements C.ProxyAdapter
 func (ss *ShadowSocks) ListenPacketOnStreamConn(c net.Conn, metadata *C.Metadata) (_ C.PacketConn, err error) {
 	if ss.option.UDPOverTCP {

adapter/outbound/shadowsocksr.go

@@ -91,6 +91,23 @@ func (ssr *ShadowSocksR) ListenPacketContext(ctx context.Context, metadata *C.Me
 	return newPacketConn(&ssPacketConn{PacketConn: pc, rAddr: addr}, ssr), nil
 }
 
+// ListenPacketOnPacketConn implements C.ProxyAdapter
+func (ssr *ShadowSocksR) ListenPacketOnPacketConn(ctx context.Context, c C.PacketConn, metadata *C.Metadata) (_ C.PacketConn, err error) {
+	addr, err := resolveUDPAddrWithPrefer(ctx, "udp", ssr.addr, ssr.prefer)
+	if err != nil {
+		return nil, err
+	}
+
+	pc := ssr.cipher.PacketConn(c)
+	pc = ssr.protocol.PacketConn(pc)
+	return newPacketConn(&ssPacketConn{PacketConn: pc, rAddr: addr}, ssr), nil
+}
+
+// SupportLPPC implements C.ProxyAdapter
+func (ssr *ShadowSocksR) SupportLPPC() bool {
+	return true
+}
+
 func NewShadowSocksR(option ShadowSocksROption) (*ShadowSocksR, error) {
 	// SSR protocol compatibility
 	// https://github.com/Dreamacro/clash/pull/2056