chore: shadowsocks listener support old cipher

constant/listener.go

@@ -1,7 +1,15 @@
 package constant
 
+import "net"
+
 type Listener interface {
 	RawAddress() string
 	Address() string
 	Close() error
 }
+
+type AdvanceListener interface {
+	Close()
+	Config() string
+	HandleConn(conn net.Conn, in chan<- ConnContext)
+}