fix tcp fastopen

shadowsocks/tcprelay.py

@@ -200,10 +200,12 @@ class TCPRelayHandler(object):
                 self._config['fast_open']:
             try:
                 self._fastopen_connected = True
+                remote_sock = self._create_remote_socket(self._chosen_server[0],
+                                                         self._chosen_server[1])
+                self._loop.add(remote_sock, eventloop.POLL_ERR)
                 data = ''.join(self._data_to_write_to_local)
                 l = len(data)
-                s = self._remote_sock.sendto(data, MSG_FASTOPEN,
-                                             self._chosen_server)
+                s = remote_sock.sendto(data, MSG_FASTOPEN, self._chosen_server)
                 if s < l:
                     data = data[s:]
                     self._data_to_write_to_local = [data]
@@ -282,6 +284,19 @@ class TCPRelayHandler(object):
             # TODO use logging when debug completed
             self.destroy()
 
+    def _create_remote_socket(self, ip, port):
+        addrs = socket.getaddrinfo(ip, port, 0, socket.SOCK_STREAM,
+                                   socket.SOL_TCP)
+        if len(addrs) == 0:
+            raise Exception("getaddrinfo failed for %s:%d" % (ip,  port))
+        af, socktype, proto, canonname, sa = addrs[0]
+        remote_sock = socket.socket(af, socktype, proto)
+        self._remote_sock = remote_sock
+        self._fd_to_handlers[remote_sock.fileno()] = self
+        remote_sock.setblocking(False)
+        remote_sock.setsockopt(socket.SOL_TCP, socket.TCP_NODELAY, 1)
+        return remote_sock
+
     def _handle_dns_resolved(self, result, error):
         if error:
             logging.error(error)
@@ -292,33 +307,22 @@ class TCPRelayHandler(object):
             if ip:
                 try:
                     self._stage = STAGE_REPLY
-                    remote_addr = self._remote_address[0]
-                    remote_port = self._remote_address[1]
+                    remote_addr = ip
                     if self._is_local:
-                        remote_addr, remote_port = self._chosen_server
-                    addrs = socket.getaddrinfo(ip, remote_port, 0,
-                                               socket.SOCK_STREAM,
-                                               socket.SOL_TCP)
-                    if len(addrs) == 0:
-                        raise Exception("getaddrinfo failed for %s:%d" %
-                                        (remote_addr, remote_port))
-                    af, socktype, proto, canonname, sa = addrs[0]
-                    remote_sock = socket.socket(af, socktype, proto)
-                    self._remote_sock = remote_sock
-                    self._fd_to_handlers[remote_sock.fileno()] = self
-                    remote_sock.setblocking(False)
-                    remote_sock.setsockopt(socket.SOL_TCP, socket.TCP_NODELAY,
-                                           1)
+                        remote_port = self._chosen_server[1]
+                    else:
+                        remote_port = self._remote_address[1]
 
                     if self._is_local and self._config['fast_open']:
                         # wait for more data to arrive and send them in one SYN
                         self._stage = STAGE_REPLY
-                        self._loop.add(remote_sock, eventloop.POLL_ERR)
                         self._update_stream(STREAM_UP, WAIT_STATUS_READING)
                         # TODO when there is already data in this packet
                     else:
+                        remote_sock = self._create_remote_socket(remote_addr,
+                                                                 remote_port)
                         try:
-                            remote_sock.connect(sa)
+                            remote_sock.connect((remote_addr, remote_port))
                         except (OSError, IOError) as e:
                             if eventloop.errno_from_exception(e) == \
                                     errno.EINPROGRESS: