udp server works

shadowsocks/udprelay.py

@@ -175,6 +175,10 @@ class UDPRelay(object):
                 # drop
                 return
             self._eventloop.add(client, eventloop.MODE_IN)
+
+        data = data[header_length:]
+        if not data:
+            return
         if self._is_local:
             data = encrypt.encrypt_all(self._password, self._method, 1, data)
             if not data: