Fix wechat protocol is not working if no obfs string is configured

pkg/conns/wechat/obfs.go

@@ -25,10 +25,13 @@ type ObfsWeChatUDPConn struct {
 	sn         uint32
 }
 
-func NewObfsWeChatUDPConn(orig *net.UDPConn, obfs obfs.Obfuscator) *ObfsWeChatUDPConn {
+func NewObfsWeChatUDPConn(orig *net.UDPConn, obfs_ obfs.Obfuscator) *ObfsWeChatUDPConn {
+	if obfs_ == nil {
+		obfs_ = obfs.NewDummyObfuscator()
+	}
 	return &ObfsWeChatUDPConn{
 		orig:     orig,
-		obfs:     obfs,
+		obfs:     obfs_,
 		readBuf:  make([]byte, udpBufferSize),
 		writeBuf: make([]byte, udpBufferSize),
 		sn:       rand.Uint32() & 0xFFFF,

pkg/obfs/dummy.go

@@ -0,0 +1,21 @@
+package obfs
+
+type DummyObfuscator struct{}
+
+func NewDummyObfuscator() *DummyObfuscator {
+	return &DummyObfuscator{}
+}
+
+func (x *DummyObfuscator) Deobfuscate(in []byte, out []byte) int {
+	pLen := len(in)
+	if pLen <= 0 || len(out) < pLen {
+		// Invalid
+		return 0
+	}
+	copy(out, in)
+	return pLen
+}
+
+func (x *DummyObfuscator) Obfuscate(in []byte, out []byte) int {
+	return copy(out, in)
+}

pkg/transport/client.go

@@ -42,12 +42,8 @@ func (ct *ClientTransport) quicPacketConn(proto string, server string, obfs obfs
 		if err != nil {
 			return nil, err
 		}
-		if obfs != nil {
-			oc := wechat.NewObfsWeChatUDPConn(conn, obfs)
-			return oc, nil
-		} else {
-			return conn, nil
-		}
+		oc := wechat.NewObfsWeChatUDPConn(conn, obfs)
+		return oc, nil
 	} else if proto == "faketcp" {
 		var conn *faketcp.TCPConn
 		conn, err := faketcp.Dial("tcp", server)

pkg/transport/server.go

@@ -101,12 +101,8 @@ func (st *ServerTransport) quicPacketConn(proto string, laddr string, obfs obfs.
 		if err != nil {
 			return nil, err
 		}
-		if obfs != nil {
-			oc := wechat.NewObfsWeChatUDPConn(conn, obfs)
-			return oc, nil
-		} else {
-			return conn, nil
-		}
+		oc := wechat.NewObfsWeChatUDPConn(conn, obfs)
+		return oc, nil
 	} else if proto == "faketcp" {
 		conn, err := faketcp.Listen("tcp", laddr)
 		if err != nil {