implement fast open in local

.travis.yml

@@ -13,3 +13,4 @@ script:
   - python test.py -c tests/salsa20.json
   - python test.py -c tests/server-multi-passwd.json
   - python test.py -c tests/workers.json
+  - python test.py -c tests/fastopen.json

shadowsocks/tcprelay.py

@@ -34,6 +34,8 @@ from common import parse_header
 TIMEOUTS_CLEAN_SIZE = 512
 TIMEOUT_PRECISION = 4
 
+MSG_FASTOPEN = 0x20000000
+
 CMD_CONNECT = 1
 CMD_BIND = 2
 CMD_UDP_ASSOCIATE = 3
@@ -199,6 +201,34 @@ class TCPRelayHandler(object):
             if is_local:
                 data = self._encryptor.encrypt(data)
             self._data_to_write_to_remote.append(data)
+            if is_local and self._upstream_status == WAIT_STATUS_INIT and \
+                    self._config['fast_open']:
+                try:
+                    data = ''.join(self._data_to_write_to_local)
+                    l = len(data)
+                    s = self._remote_sock.sendto(data, MSG_FASTOPEN,
+                                                 self.remote_address)
+                    if s < l:
+                        data = data[s:]
+                        self._data_to_write_to_local = [data]
+                        self.update_stream(STREAM_UP, WAIT_STATUS_READWRITING)
+                        self.update_stream(STREAM_DOWN, WAIT_STATUS_READING)
+                    else:
+                        self._data_to_write_to_local = []
+                        self.update_stream(STREAM_UP, WAIT_STATUS_READING)
+                        self.update_stream(STREAM_DOWN, WAIT_STATUS_READING)
+                        self._stage = STAGE_STREAM
+                except (OSError, IOError) as e:
+                    if eventloop.errno_from_exception(e) == errno.EINPROGRESS:
+                        self.update_stream(STREAM_UP, WAIT_STATUS_READWRITING)
+                        self.update_stream(STREAM_DOWN, WAIT_STATUS_READING)
+                    elif eventloop.errno_from_exception(e) == errno.ENOTCONN:
+                        logging.error('fast open not supported on this OS')
+                        self._config['fast_open'] = False
+                        self.destroy()
+                    else:
+                        logging.error(e)
+                        self.destroy()
         elif (is_local and self._stage == STAGE_HELLO) or \
                 (not is_local and self._stage == STAGE_INIT):
             try:
@@ -259,15 +289,20 @@ class TCPRelayHandler(object):
                 self._fd_to_handlers[remote_sock.fileno()] = self
                 remote_sock.setblocking(False)
                 remote_sock.setsockopt(socket.SOL_TCP, socket.TCP_NODELAY, 1)
-                # TODO support TCP fast open
+
+                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
+                    # TODO when there is already data in this packet
+                else:
                     try:
                         remote_sock.connect(sa)
                     except (OSError, IOError) as e:
-                    if eventloop.errno_from_exception(e) == errno.EINPROGRESS:
+                        if eventloop.errno_from_exception(e) == \
+                                errno.EINPROGRESS:
                             pass
                     self._loop.add(remote_sock,
                                    eventloop.POLL_ERR | eventloop.POLL_OUT)
-
                     self._stage = STAGE_REPLY
                     self.update_stream(STREAM_UP, WAIT_STATUS_READWRITING)
                     self.update_stream(STREAM_DOWN, WAIT_STATUS_READING)

tests/fastopen.json

@@ -0,0 +1,10 @@
+{
+    "server":"127.0.0.1",
+    "server_port":8388,
+    "local_port":1081,
+    "password":"barfoo!",
+    "timeout":300,
+    "method":"aes-256-cfb",
+    "local_address":"127.0.0.1",
+    "fast_open":true
+}