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1 | # Public Domain SOCKS proxy protocol implementation |
2 | # Adapted from https://gist.github.com/bluec0re/cafd3764412967417fd3 | |
3 | ||
4 | from __future__ import unicode_literals | |
5 | ||
6 | # References: | |
7 | # SOCKS4 protocol http://www.openssh.com/txt/socks4.protocol | |
8 | # SOCKS4A protocol http://www.openssh.com/txt/socks4a.protocol | |
9 | # SOCKS5 protocol https://tools.ietf.org/html/rfc1928 | |
10 | # SOCKS5 username/password authentication https://tools.ietf.org/html/rfc1929 | |
11 | ||
12 | import collections | |
13 | import socket | |
14 | ||
15 | from .compat import ( | |
16 | compat_ord, | |
17 | compat_struct_pack, | |
18 | compat_struct_unpack, | |
19 | ) | |
20 | ||
21 | __author__ = 'Timo Schmid <coding@timoschmid.de>' | |
22 | ||
23 | SOCKS4_VERSION = 4 | |
24 | SOCKS4_REPLY_VERSION = 0x00 | |
25 | # Excerpt from SOCKS4A protocol: | |
26 | # if the client cannot resolve the destination host's domain name to find its | |
27 | # IP address, it should set the first three bytes of DSTIP to NULL and the last | |
28 | # byte to a non-zero value. | |
29 | SOCKS4_DEFAULT_DSTIP = compat_struct_pack('!BBBB', 0, 0, 0, 0xFF) | |
30 | ||
31 | SOCKS5_VERSION = 5 | |
32 | SOCKS5_USER_AUTH_VERSION = 0x01 | |
33 | SOCKS5_USER_AUTH_SUCCESS = 0x00 | |
34 | ||
35 | ||
36 | class Socks4Command(object): | |
37 | CMD_CONNECT = 0x01 | |
38 | CMD_BIND = 0x02 | |
39 | ||
40 | ||
41 | class Socks5Command(Socks4Command): | |
42 | CMD_UDP_ASSOCIATE = 0x03 | |
43 | ||
44 | ||
45 | class Socks5Auth(object): | |
46 | AUTH_NONE = 0x00 | |
47 | AUTH_GSSAPI = 0x01 | |
48 | AUTH_USER_PASS = 0x02 | |
49 | AUTH_NO_ACCEPTABLE = 0xFF # For server response | |
50 | ||
51 | ||
52 | class Socks5AddressType(object): | |
53 | ATYP_IPV4 = 0x01 | |
54 | ATYP_DOMAINNAME = 0x03 | |
55 | ATYP_IPV6 = 0x04 | |
56 | ||
57 | ||
58 | class ProxyError(socket.error): | |
59 | ERR_SUCCESS = 0x00 | |
60 | ||
61 | def __init__(self, code=None, msg=None): | |
62 | if code is not None and msg is None: | |
63 | msg = self.CODES.get(code) or 'unknown error' | |
64 | super(ProxyError, self).__init__(code, msg) | |
65 | ||
66 | ||
67 | class InvalidVersionError(ProxyError): | |
68 | def __init__(self, expected_version, got_version): | |
69 | msg = ('Invalid response version from server. Expected {0:02x} got ' | |
70 | '{1:02x}'.format(expected_version, got_version)) | |
71 | super(InvalidVersionError, self).__init__(0, msg) | |
72 | ||
73 | ||
74 | class Socks4Error(ProxyError): | |
75 | ERR_SUCCESS = 90 | |
76 | ||
77 | CODES = { | |
78 | 91: 'request rejected or failed', | |
79 | 92: 'request rejected because SOCKS server cannot connect to identd on the client', | |
80 | 93: 'request rejected because the client program and identd report different user-ids' | |
81 | } | |
82 | ||
83 | ||
84 | class Socks5Error(ProxyError): | |
85 | ERR_GENERAL_FAILURE = 0x01 | |
86 | ||
87 | CODES = { | |
88 | 0x01: 'general SOCKS server failure', | |
89 | 0x02: 'connection not allowed by ruleset', | |
90 | 0x03: 'Network unreachable', | |
91 | 0x04: 'Host unreachable', | |
92 | 0x05: 'Connection refused', | |
93 | 0x06: 'TTL expired', | |
94 | 0x07: 'Command not supported', | |
95 | 0x08: 'Address type not supported', | |
96 | 0xFE: 'unknown username or invalid password', | |
97 | 0xFF: 'all offered authentication methods were rejected' | |
98 | } | |
99 | ||
100 | ||
101 | class ProxyType(object): | |
102 | SOCKS4 = 0 | |
103 | SOCKS4A = 1 | |
104 | SOCKS5 = 2 | |
105 | ||
106 | ||
107 | Proxy = collections.namedtuple('Proxy', ( | |
108 | 'type', 'host', 'port', 'username', 'password', 'remote_dns')) | |
109 | ||
110 | ||
111 | class sockssocket(socket.socket): | |
112 | def __init__(self, *args, **kwargs): | |
113 | self._proxy = None | |
114 | super(sockssocket, self).__init__(*args, **kwargs) | |
115 | ||
116 | def setproxy(self, proxytype, addr, port, rdns=True, username=None, password=None): | |
117 | assert proxytype in (ProxyType.SOCKS4, ProxyType.SOCKS4A, ProxyType.SOCKS5) | |
118 | ||
119 | self._proxy = Proxy(proxytype, addr, port, username, password, rdns) | |
120 | ||
121 | def recvall(self, cnt): | |
122 | data = b'' | |
123 | while len(data) < cnt: | |
124 | cur = self.recv(cnt - len(data)) | |
125 | if not cur: | |
126 | raise EOFError('{0} bytes missing'.format(cnt - len(data))) | |
127 | data += cur | |
128 | return data | |
129 | ||
130 | def _recv_bytes(self, cnt): | |
131 | data = self.recvall(cnt) | |
132 | return compat_struct_unpack('!{0}B'.format(cnt), data) | |
133 | ||
134 | @staticmethod | |
135 | def _len_and_data(data): | |
136 | return compat_struct_pack('!B', len(data)) + data | |
137 | ||
138 | def _check_response_version(self, expected_version, got_version): | |
139 | if got_version != expected_version: | |
140 | self.close() | |
141 | raise InvalidVersionError(expected_version, got_version) | |
142 | ||
143 | def _resolve_address(self, destaddr, default, use_remote_dns): | |
144 | try: | |
145 | return socket.inet_aton(destaddr) | |
146 | except socket.error: | |
147 | if use_remote_dns and self._proxy.remote_dns: | |
148 | return default | |
149 | else: | |
150 | return socket.inet_aton(socket.gethostbyname(destaddr)) | |
151 | ||
152 | def _setup_socks4(self, address, is_4a=False): | |
153 | destaddr, port = address | |
154 | ||
155 | ipaddr = self._resolve_address(destaddr, SOCKS4_DEFAULT_DSTIP, use_remote_dns=is_4a) | |
156 | ||
157 | packet = compat_struct_pack('!BBH', SOCKS4_VERSION, Socks4Command.CMD_CONNECT, port) + ipaddr | |
158 | ||
159 | username = (self._proxy.username or '').encode('utf-8') | |
160 | packet += username + b'\x00' | |
161 | ||
162 | if is_4a and self._proxy.remote_dns: | |
163 | packet += destaddr.encode('utf-8') + b'\x00' | |
164 | ||
165 | self.sendall(packet) | |
166 | ||
167 | version, resp_code, dstport, dsthost = compat_struct_unpack('!BBHI', self.recvall(8)) | |
168 | ||
169 | self._check_response_version(SOCKS4_REPLY_VERSION, version) | |
170 | ||
171 | if resp_code != Socks4Error.ERR_SUCCESS: | |
172 | self.close() | |
173 | raise Socks4Error(resp_code) | |
174 | ||
175 | return (dsthost, dstport) | |
176 | ||
177 | def _setup_socks4a(self, address): | |
178 | self._setup_socks4(address, is_4a=True) | |
179 | ||
180 | def _socks5_auth(self): | |
181 | packet = compat_struct_pack('!B', SOCKS5_VERSION) | |
182 | ||
183 | auth_methods = [Socks5Auth.AUTH_NONE] | |
184 | if self._proxy.username and self._proxy.password: | |
185 | auth_methods.append(Socks5Auth.AUTH_USER_PASS) | |
186 | ||
187 | packet += compat_struct_pack('!B', len(auth_methods)) | |
188 | packet += compat_struct_pack('!{0}B'.format(len(auth_methods)), *auth_methods) | |
189 | ||
190 | self.sendall(packet) | |
191 | ||
192 | version, method = self._recv_bytes(2) | |
193 | ||
194 | self._check_response_version(SOCKS5_VERSION, version) | |
195 | ||
196 | if method == Socks5Auth.AUTH_NO_ACCEPTABLE or ( | |
197 | method == Socks5Auth.AUTH_USER_PASS and (not self._proxy.username or not self._proxy.password)): | |
198 | self.close() | |
199 | raise Socks5Error(Socks5Auth.AUTH_NO_ACCEPTABLE) | |
200 | ||
201 | if method == Socks5Auth.AUTH_USER_PASS: | |
202 | username = self._proxy.username.encode('utf-8') | |
203 | password = self._proxy.password.encode('utf-8') | |
204 | packet = compat_struct_pack('!B', SOCKS5_USER_AUTH_VERSION) | |
205 | packet += self._len_and_data(username) + self._len_and_data(password) | |
206 | self.sendall(packet) | |
207 | ||
208 | version, status = self._recv_bytes(2) | |
209 | ||
210 | self._check_response_version(SOCKS5_USER_AUTH_VERSION, version) | |
211 | ||
212 | if status != SOCKS5_USER_AUTH_SUCCESS: | |
213 | self.close() | |
214 | raise Socks5Error(Socks5Error.ERR_GENERAL_FAILURE) | |
215 | ||
216 | def _setup_socks5(self, address): | |
217 | destaddr, port = address | |
218 | ||
219 | ipaddr = self._resolve_address(destaddr, None, use_remote_dns=True) | |
220 | ||
221 | self._socks5_auth() | |
222 | ||
223 | reserved = 0 | |
224 | packet = compat_struct_pack('!BBB', SOCKS5_VERSION, Socks5Command.CMD_CONNECT, reserved) | |
225 | if ipaddr is None: | |
226 | destaddr = destaddr.encode('utf-8') | |
227 | packet += compat_struct_pack('!B', Socks5AddressType.ATYP_DOMAINNAME) | |
228 | packet += self._len_and_data(destaddr) | |
229 | else: | |
230 | packet += compat_struct_pack('!B', Socks5AddressType.ATYP_IPV4) + ipaddr | |
231 | packet += compat_struct_pack('!H', port) | |
232 | ||
233 | self.sendall(packet) | |
234 | ||
235 | version, status, reserved, atype = self._recv_bytes(4) | |
236 | ||
237 | self._check_response_version(SOCKS5_VERSION, version) | |
238 | ||
239 | if status != Socks5Error.ERR_SUCCESS: | |
240 | self.close() | |
241 | raise Socks5Error(status) | |
242 | ||
243 | if atype == Socks5AddressType.ATYP_IPV4: | |
244 | destaddr = self.recvall(4) | |
245 | elif atype == Socks5AddressType.ATYP_DOMAINNAME: | |
246 | alen = compat_ord(self.recv(1)) | |
247 | destaddr = self.recvall(alen) | |
248 | elif atype == Socks5AddressType.ATYP_IPV6: | |
249 | destaddr = self.recvall(16) | |
250 | destport = compat_struct_unpack('!H', self.recvall(2))[0] | |
251 | ||
252 | return (destaddr, destport) | |
253 | ||
254 | def _make_proxy(self, connect_func, address): | |
255 | if not self._proxy: | |
256 | return connect_func(self, address) | |
257 | ||
258 | result = connect_func(self, (self._proxy.host, self._proxy.port)) | |
259 | if result != 0 and result is not None: | |
260 | return result | |
261 | setup_funcs = { | |
262 | ProxyType.SOCKS4: self._setup_socks4, | |
263 | ProxyType.SOCKS4A: self._setup_socks4a, | |
264 | ProxyType.SOCKS5: self._setup_socks5, | |
265 | } | |
266 | setup_funcs[self._proxy.type](address) | |
267 | return result | |
268 | ||
269 | def connect(self, address): | |
270 | self._make_proxy(socket.socket.connect, address) | |
271 | ||
272 | def connect_ex(self, address): | |
273 | return self._make_proxy(socket.socket.connect_ex, address) |