def _do_socks5_connect_response(self, data):
# response:
# +-----+-----+-------+------+----------+----------+
# | VER | REP | RSV | ATYP | BND.ADDR | BND.PORT |
# +-----+-----+-------+------+----------+----------+
# | 1 | 1 | X'00' | 1 | Variable | 2 |
# +-----+-----+-------+------+----------+----------+
#
if len(data) < 10:
settings.PROTO_LOG.error(constants.ERROR_MSG_NOT_ENOUGHT_DATA_FOR.format('socks5 method connect response'))
self.transport.close()
return False
version, reply_code, _ = STRUCT_BBB.unpack_from(data)
if reply_code == constants.SOCKS5_REPLY_SUCCEEDED:
try:
addr = Socks5AddrHeader()
length = addr.from_bytes(data[STRUCT_BBB.size:])
return True
except ValueError:
settings.PROTO_LOG.exception('Fail to parse addr')
self.transport.close()
return False
else:
# When a reply (REP value other than X'00') indicates a failure, the
# SOCKS server MUST terminate the TCP connection shortly after sending
# the reply. Here we close the client too.
settings.PROTO_LOG.error('error code for connect response:%d', reply_code)
self.transport.close()
return False
def conn_completed(future):
# socks5 states: In the reply to a CONNECT, BND.PORT contains the port number that
# the server assigned to connect to the target host, while BND.ADDR contains the associated IP address.
ret, (foward_addr, foward_port) = future.result()
if not ret:
self._write_error_socks_response_with_reply_code(
constants.SOCKS5_REPLY_NETWORK_UNREACHABLE)
return False
else:
# If the reply code (REP value of X'00') indicates a success,
# and the request was either a BIND or a CONNECT, the client may now start passing data.
self._write_succeed_socks_response_with_addr(
Socks5AddrHeader(
addr=foward_addr,
port=foward_port,
addr_type=what_type_of_the_address(
foward_addr),
))
if cmd == constants.SOCKS5_CMD_CONNECT:
self.state = STAGE_SOCKS5_TCP_RELAY
elif cmd == constants.SOCKS5_CMD_UDP_ASSOCIATE:
self.state = STAGE_SOCKS5_UDP_ASSOCIATE
# close the connection and go to the UDP relay server for data relay
self.transport.close()
def _send_socks5_connect_request(self):
#
# resquest:
# +-----+-----+-------+------+----------+----------+
# | VER | CMD | RSV | ATYP | DST.ADDR | DST.PORT |
# +-----+-----+-------+------+----------+----------+
# | 1 | 1 | X'00' | 1 | Variable | 2 |
# +-----+-----+-------+------+----------+----------+
#
addr = Socks5AddrHeader()
addr.addr = self.target_host
addr.port = self.target_port
addr.addr_type = what_type_of_the_address(self.target_host)
data = STRUCT_BBB.pack(constants.SOCKS5_VERSION,
constants.SOCKS5_CMD_CONNECT,
constants.SOCKS5_RESERVED_BYTE,
) + addr.to_bytes()
self.transport.write(data)
return True
def _parse_socks_request(self, data):
"""
return the CMD and address(extract from DST.addr DST.port),
if ERROR, close the transport and return (False, None, None)
"""
if len(data) < 10:
settings.PROTO_LOG.error('no enough data for SOCKS request')
self.transport.close()
return False
version, cmd, _ = STRUCT_BBB.unpack_from(data)
addr = Socks5AddrHeader()
try:
length = addr.from_bytes(data[STRUCT_BBB.size:])
except ValueError:
settings.PROTO_LOG.exception('Fail to get addr')
self._write_error_socks_response_with_reply_code(constants.SOCKS_REPLY_ADDRESS_TYPE_NOT_SUPPORTED)
return False, None, None
else:
return True, cmd, addr