rewriting protocol

auth.py

@@ -0,0 +1,8 @@
+
+acceptable_auth_methods = [NoAuthRequired]
+acceptable_auth_method_codes = [method.method_code for method in acceptable_auth_methods]
+
+class NoAuthRequired:
+ method_code = b'\x00'
+
+

exceptions.py

@@ -11,3 +11,9 @@ class ConnectionError(Exception):
 
 class RequestNotSucceed(Exception):
  pass
+
+class InvalidRequest(Exception):
+ pass
+
+class WrongProtocol(InvalidRequest):
+ pass

protocol.py

@@ -0,0 +1,99 @@
+import auth
+from exceptions import InvalidRequest, WrongProtocol
+
+import asyncio
+
+class Socks5ProtocolState:
+
+ INIT = 0
+ NEGOTIATED = 1
+ AUTHORIZED = 2
+ CONNECTED = 3
+
+
+class Socks5Protocol(asyncio.Protocol)
+
+ def __init__(self):
+ self.transport = None
+ self.state = Socks5Protocol.INIT
+
+ def _next_state(self, skips=0):
+ """ Move protocol state forward by one plus skips"""
+ self.state += 1 + skips
+
+ def connection_made(self, transport):
+ peername = transport.get_extra_info('peername')
+ print('Receive connection from {}.'.format(peername))
+ self.transport = transport
+
+ def data_received(self, data):
+ if self.state == Socks5ProtocolState.INIT:
+ self._negotiate_auth_method(data)
+ elif self.state == Socks5ProtocolState.NEGOTIATED:
+ raise NotImplemented 
+ elif self.state == Socks5ProtocolState.AUTHORIZED:
+ self._connect(data) 
+
+
+
+ def _negotiate_auth_method(self, data):
+ if len(data) <= 2:
+ raise InvalidRequest
+ if data[0] != b'\x05':
+ raise WrongProtocol
+
+ auth_method_count = int(data[1], 16)
+ auth_method_codes = list(data[2:])
+ if len(auth_method_codes) < auth_method_count:
+ raise InvalidRequest
+
+ # no auth emthod proposed by client is accept
+ accepted_code = '\xff' 
+
+ for auth_method_code in auth_method_codes:
+ if auth_method_code in auth.acceptable_auth_method_codes:
+ accepted_code = auth_method_code 
+ break
+
+ respone = '\x05' + accepted_code
+ self.transport.write(response)
+ self.state = self.state
+
+ # skip the auth phase when not required
+ self._next_state(self.accepted_code == auth.NoAuthRequired.method_code)
+
+ def _connect(self, data):
+ version = data[:1] 
+ assert version == '\x05'
+ cmd = data[1:2]
+ assert int(cmd, 16) == 1
+ addr_type = int(data[3:4], 16)
+ assert addr_type in (1, 3, 4) 
+ if addr_type == 1:
+ addr = data[4:8]
+ addr = ':'.join([for byte in addr])
+ elif addr_type == 3:
+ addr_octets_count = int(data[4], 16)
+ addr = data[5:5+addr_octets_count]
+ else:
+ addr = data[4:20]
+
+
+ def _channeling(self, data):
+
+
+
+
+loop = asyncio.get_event_loop()
+coro = loop.create_server(Socks5Protocol, '127.0.0.1', 1080)
+server = loop.run_until_complete(coro)
+
+try:
+ loop.run_forever()
+except KeyboardInterrupt:
+ pass
+
+server.close()
+loop.run_until_complete(server.wait_closed())
+loop.close()
+