From 238838f96b4680dfa899a65da9b2c8fadc3db2f9 Mon Sep 17 00:00:00 2001
From: nanwu <nanbytesflow@gmail.com>
Date: Mon, 1 May 2017 18:22:34 -0400
Subject: [PATCH] rewriting protocol

---
 auth.py       |  8 +++++
 exceptions.py |  6 ++++
 protocol.py   | 99 +++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 113 insertions(+)
 create mode 100644 auth.py
 create mode 100644 protocol.py

diff --git a/auth.py b/auth.py
new file mode 100644
index 0000000..e7e6875
--- /dev/null
+++ b/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'
+
+    
diff --git a/exceptions.py b/exceptions.py
index c0d55fa..d7ebc3d 100644
--- a/exceptions.py
+++ b/exceptions.py
@@ -11,3 +11,9 @@ class ConnectionError(Exception):
 
 class RequestNotSucceed(Exception):
     pass
+
+class InvalidRequest(Exception):
+    pass
+
+class WrongProtocol(InvalidRequest):
+    pass
diff --git a/protocol.py b/protocol.py
new file mode 100644
index 0000000..c58fcfd
--- /dev/null
+++ b/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()
+