274 lines
8.7 KiB
Python
274 lines
8.7 KiB
Python
# Public Domain SOCKS proxy protocol implementation
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# Adapted from https://gist.github.com/bluec0re/cafd3764412967417fd3
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from __future__ import unicode_literals
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# References:
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# SOCKS4 protocol http://www.openssh.com/txt/socks4.protocol
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# SOCKS4A protocol http://www.openssh.com/txt/socks4a.protocol
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# SOCKS5 protocol https://tools.ietf.org/html/rfc1928
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# SOCKS5 username/password authentication https://tools.ietf.org/html/rfc1929
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import collections
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import socket
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from .compat import (
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compat_ord,
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compat_struct_pack,
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compat_struct_unpack,
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)
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__author__ = 'Timo Schmid <coding@timoschmid.de>'
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SOCKS4_VERSION = 4
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SOCKS4_REPLY_VERSION = 0x00
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# Excerpt from SOCKS4A protocol:
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# if the client cannot resolve the destination host's domain name to find its
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# IP address, it should set the first three bytes of DSTIP to NULL and the last
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# byte to a non-zero value.
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SOCKS4_DEFAULT_DSTIP = compat_struct_pack('!BBBB', 0, 0, 0, 0xFF)
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SOCKS5_VERSION = 5
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SOCKS5_USER_AUTH_VERSION = 0x01
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SOCKS5_USER_AUTH_SUCCESS = 0x00
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class Socks4Command(object):
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CMD_CONNECT = 0x01
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CMD_BIND = 0x02
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class Socks5Command(Socks4Command):
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CMD_UDP_ASSOCIATE = 0x03
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class Socks5Auth(object):
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AUTH_NONE = 0x00
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AUTH_GSSAPI = 0x01
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AUTH_USER_PASS = 0x02
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AUTH_NO_ACCEPTABLE = 0xFF # For server response
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class Socks5AddressType(object):
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ATYP_IPV4 = 0x01
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ATYP_DOMAINNAME = 0x03
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ATYP_IPV6 = 0x04
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class ProxyError(socket.error):
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ERR_SUCCESS = 0x00
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def __init__(self, code=None, msg=None):
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if code is not None and msg is None:
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msg = self.CODES.get(code) or 'unknown error'
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super(ProxyError, self).__init__(code, msg)
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class InvalidVersionError(ProxyError):
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def __init__(self, expected_version, got_version):
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msg = ('Invalid response version from server. Expected {0:02x} got '
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'{1:02x}'.format(expected_version, got_version))
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super(InvalidVersionError, self).__init__(0, msg)
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class Socks4Error(ProxyError):
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ERR_SUCCESS = 90
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CODES = {
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91: 'request rejected or failed',
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92: 'request rejected because SOCKS server cannot connect to identd on the client',
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93: 'request rejected because the client program and identd report different user-ids'
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}
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class Socks5Error(ProxyError):
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ERR_GENERAL_FAILURE = 0x01
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CODES = {
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0x01: 'general SOCKS server failure',
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0x02: 'connection not allowed by ruleset',
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0x03: 'Network unreachable',
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0x04: 'Host unreachable',
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0x05: 'Connection refused',
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0x06: 'TTL expired',
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0x07: 'Command not supported',
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0x08: 'Address type not supported',
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0xFE: 'unknown username or invalid password',
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0xFF: 'all offered authentication methods were rejected'
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}
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class ProxyType(object):
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SOCKS4 = 0
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SOCKS4A = 1
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SOCKS5 = 2
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Proxy = collections.namedtuple('Proxy', (
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'type', 'host', 'port', 'username', 'password', 'remote_dns'))
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class sockssocket(socket.socket):
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def __init__(self, *args, **kwargs):
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self._proxy = None
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super(sockssocket, self).__init__(*args, **kwargs)
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def setproxy(self, proxytype, addr, port, rdns=True, username=None, password=None):
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assert proxytype in (ProxyType.SOCKS4, ProxyType.SOCKS4A, ProxyType.SOCKS5)
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self._proxy = Proxy(proxytype, addr, port, username, password, rdns)
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def recvall(self, cnt):
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data = b''
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while len(data) < cnt:
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cur = self.recv(cnt - len(data))
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if not cur:
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raise EOFError('{0} bytes missing'.format(cnt - len(data)))
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data += cur
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return data
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def _recv_bytes(self, cnt):
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data = self.recvall(cnt)
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return compat_struct_unpack('!{0}B'.format(cnt), data)
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@staticmethod
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def _len_and_data(data):
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return compat_struct_pack('!B', len(data)) + data
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def _check_response_version(self, expected_version, got_version):
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if got_version != expected_version:
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self.close()
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raise InvalidVersionError(expected_version, got_version)
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def _resolve_address(self, destaddr, default, use_remote_dns):
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try:
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return socket.inet_aton(destaddr)
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except socket.error:
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if use_remote_dns and self._proxy.remote_dns:
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return default
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else:
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return socket.inet_aton(socket.gethostbyname(destaddr))
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def _setup_socks4(self, address, is_4a=False):
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destaddr, port = address
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ipaddr = self._resolve_address(destaddr, SOCKS4_DEFAULT_DSTIP, use_remote_dns=is_4a)
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packet = compat_struct_pack('!BBH', SOCKS4_VERSION, Socks4Command.CMD_CONNECT, port) + ipaddr
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username = (self._proxy.username or '').encode('utf-8')
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packet += username + b'\x00'
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if is_4a and self._proxy.remote_dns:
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packet += destaddr.encode('utf-8') + b'\x00'
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self.sendall(packet)
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version, resp_code, dstport, dsthost = compat_struct_unpack('!BBHI', self.recvall(8))
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self._check_response_version(SOCKS4_REPLY_VERSION, version)
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if resp_code != Socks4Error.ERR_SUCCESS:
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self.close()
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raise Socks4Error(resp_code)
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return (dsthost, dstport)
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def _setup_socks4a(self, address):
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self._setup_socks4(address, is_4a=True)
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def _socks5_auth(self):
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packet = compat_struct_pack('!B', SOCKS5_VERSION)
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auth_methods = [Socks5Auth.AUTH_NONE]
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if self._proxy.username and self._proxy.password:
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auth_methods.append(Socks5Auth.AUTH_USER_PASS)
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packet += compat_struct_pack('!B', len(auth_methods))
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packet += compat_struct_pack('!{0}B'.format(len(auth_methods)), *auth_methods)
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self.sendall(packet)
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version, method = self._recv_bytes(2)
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self._check_response_version(SOCKS5_VERSION, version)
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if method == Socks5Auth.AUTH_NO_ACCEPTABLE or (
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method == Socks5Auth.AUTH_USER_PASS and (not self._proxy.username or not self._proxy.password)):
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self.close()
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raise Socks5Error(Socks5Auth.AUTH_NO_ACCEPTABLE)
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if method == Socks5Auth.AUTH_USER_PASS:
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username = self._proxy.username.encode('utf-8')
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password = self._proxy.password.encode('utf-8')
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packet = compat_struct_pack('!B', SOCKS5_USER_AUTH_VERSION)
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packet += self._len_and_data(username) + self._len_and_data(password)
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self.sendall(packet)
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version, status = self._recv_bytes(2)
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self._check_response_version(SOCKS5_USER_AUTH_VERSION, version)
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if status != SOCKS5_USER_AUTH_SUCCESS:
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self.close()
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raise Socks5Error(Socks5Error.ERR_GENERAL_FAILURE)
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def _setup_socks5(self, address):
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destaddr, port = address
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ipaddr = self._resolve_address(destaddr, None, use_remote_dns=True)
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self._socks5_auth()
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reserved = 0
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packet = compat_struct_pack('!BBB', SOCKS5_VERSION, Socks5Command.CMD_CONNECT, reserved)
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if ipaddr is None:
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destaddr = destaddr.encode('utf-8')
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packet += compat_struct_pack('!B', Socks5AddressType.ATYP_DOMAINNAME)
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packet += self._len_and_data(destaddr)
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else:
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packet += compat_struct_pack('!B', Socks5AddressType.ATYP_IPV4) + ipaddr
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packet += compat_struct_pack('!H', port)
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self.sendall(packet)
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version, status, reserved, atype = self._recv_bytes(4)
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self._check_response_version(SOCKS5_VERSION, version)
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if status != Socks5Error.ERR_SUCCESS:
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self.close()
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raise Socks5Error(status)
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if atype == Socks5AddressType.ATYP_IPV4:
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destaddr = self.recvall(4)
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elif atype == Socks5AddressType.ATYP_DOMAINNAME:
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alen = compat_ord(self.recv(1))
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destaddr = self.recvall(alen)
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elif atype == Socks5AddressType.ATYP_IPV6:
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destaddr = self.recvall(16)
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destport = compat_struct_unpack('!H', self.recvall(2))[0]
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return (destaddr, destport)
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def _make_proxy(self, connect_func, address):
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if not self._proxy:
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return connect_func(self, address)
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result = connect_func(self, (self._proxy.host, self._proxy.port))
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if result != 0 and result is not None:
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return result
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setup_funcs = {
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ProxyType.SOCKS4: self._setup_socks4,
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ProxyType.SOCKS4A: self._setup_socks4a,
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ProxyType.SOCKS5: self._setup_socks5,
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}
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setup_funcs[self._proxy.type](address)
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return result
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def connect(self, address):
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self._make_proxy(socket.socket.connect, address)
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def connect_ex(self, address):
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return self._make_proxy(socket.socket.connect_ex, address)
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