Neil Booth
7 years ago
4 changed files with 57 additions and 256 deletions
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# Copyright (c) 2017, Neil Booth |
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# |
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# All rights reserved. |
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# |
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# The MIT License (MIT) |
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# |
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# Permission is hereby granted, free of charge, to any person obtaining |
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# a copy of this software and associated documentation files (the |
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# "Software"), to deal in the Software without restriction, including |
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# without limitation the rights to use, copy, modify, merge, publish, |
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# distribute, sublicense, and/or sell copies of the Software, and to |
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# permit persons to whom the Software is furnished to do so, subject to |
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# the following conditions: |
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# |
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# The above copyright notice and this permission notice shall be |
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# included in all copies or substantial portions of the Software. |
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# |
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, |
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# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF |
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# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND |
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# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE |
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# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION |
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# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION |
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# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. |
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# and warranty status of this software. |
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|
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'''Socks proxying.''' |
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|
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import asyncio |
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import ipaddress |
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import logging |
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import socket |
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import struct |
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from functools import partial |
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|
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import lib.util as util |
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|
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|
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class Socks(util.LoggedClass): |
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'''Socks protocol wrapper.''' |
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|
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SOCKS5_ERRORS = { |
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1: 'general SOCKS server failure', |
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2: 'connection not allowed by ruleset', |
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3: 'network unreachable', |
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4: 'host unreachable', |
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5: 'connection refused', |
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6: 'TTL expired', |
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7: 'command not supported', |
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8: 'address type not supported', |
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} |
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|
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class Error(Exception): |
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pass |
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|
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def __init__(self, loop, sock, host, port): |
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super().__init__() |
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self.loop = loop |
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self.sock = sock |
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self.host = host |
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self.port = port |
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try: |
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self.ip_address = ipaddress.ip_address(host) |
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except ValueError: |
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self.ip_address = None |
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self.debug = False |
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|
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async def _socks4_handshake(self): |
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if self.ip_address: |
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# Socks 4 |
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ip_addr = self.ip_address |
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host_bytes = b'' |
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else: |
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# Socks 4a |
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ip_addr = ipaddress.ip_address('0.0.0.1') |
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host_bytes = self.host.encode() + b'\0' |
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|
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user_id = '' |
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data = b'\4\1' + struct.pack('>H', self.port) + ip_addr.packed |
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data += user_id.encode() + b'\0' + host_bytes |
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await self.loop.sock_sendall(self.sock, data) |
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data = await self.loop.sock_recv(self.sock, 8) |
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if data[0] != 0: |
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raise self.Error('proxy sent bad initial Socks4 byte') |
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if data[1] != 0x5a: |
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raise self.Error('proxy request failed or rejected') |
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|
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async def _socks5_handshake(self): |
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await self.loop.sock_sendall(self.sock, b'\5\1\0') |
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data = await self.loop.sock_recv(self.sock, 2) |
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if data[0] != 5: |
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raise self.Error('proxy sent bad SOCKS5 initial byte') |
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if data[1] != 0: |
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raise self.Error('proxy rejected SOCKS5 authentication method') |
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|
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if self.ip_address: |
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if self.ip_address.version == 4: |
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addr = b'\1' + self.ip_address.packed |
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else: |
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addr = b'\4' + self.ip_address.packed |
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else: |
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host = self.host.encode() |
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addr = b'\3' + bytes([len(host)]) + host |
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|
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data = b'\5\1\0' + addr + struct.pack('>H', self.port) |
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await self.loop.sock_sendall(self.sock, data) |
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data = await self.loop.sock_recv(self.sock, 5) |
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if data[0] != 5: |
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raise self.Error('proxy sent bad SOSCK5 response initial byte') |
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if data[1] != 0: |
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msg = self.SOCKS5_ERRORS.get(data[1], 'unknown SOCKS5 error {:d}' |
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.format(data[1])) |
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raise self.Error(msg) |
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if data[3] == 1: |
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addr_len, data = 3, data[4:] |
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elif data[3] == 3: |
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addr_len, data = data[4], b'' |
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elif data[3] == 4: |
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addr_len, data = 15, data[4:] |
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data = await self.loop.sock_recv(self.sock, addr_len + 2) |
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addr = data[:addr_len] |
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port, = struct.unpack('>H', data[-2:]) |
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|
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async def handshake(self): |
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'''Write the proxy handshake sequence.''' |
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if self.ip_address and self.ip_address.version == 6: |
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await self._socks5_handshake() |
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else: |
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await self._socks4_handshake() |
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|
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if self.debug: |
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address = (self.host, self.port) |
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self.log_info('successful connection via proxy to {}' |
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.format(util.address_string(address))) |
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|
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|
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class SocksProxy(util.LoggedClass): |
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|
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def __init__(self, host, port, loop): |
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'''Host can be an IPv4 address, IPv6 address, or a host name. |
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Port can be None, in which case one is auto-detected.''' |
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super().__init__() |
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# Host and port of the proxy |
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self.host = host |
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self.try_ports = [port, 9050, 9150, 1080] |
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self.errors = 0 |
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self.ip_addr = None |
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self.lost_event = asyncio.Event() |
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self.tried_event = asyncio.Event() |
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self.loop = loop |
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self.set_lost() |
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|
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async def auto_detect_loop(self): |
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'''Try to detect a proxy at regular intervals until one is found. |
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If one is found, do nothing until one is lost.''' |
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while True: |
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await self.lost_event.wait() |
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self.lost_event.clear() |
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tries = 0 |
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while True: |
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tries += 1 |
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log_failure = tries % 10 == 1 |
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await self.detect_proxy(log_failure=log_failure) |
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if self.is_up(): |
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break |
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await asyncio.sleep(600) |
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def is_up(self): |
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'''Returns True if we have a good proxy.''' |
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return self.port is not None |
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|
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def set_lost(self): |
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'''Called when the proxy appears lost/down.''' |
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self.port = None |
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self.lost_event.set() |
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|
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async def connect_via_proxy(self, host, port, proxy_address=None): |
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'''Connect to a (host, port) pair via the proxy. Returns the |
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connected socket on success.''' |
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proxy_address = proxy_address or (self.host, self.port) |
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sock = socket.socket() |
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sock.setblocking(False) |
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try: |
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await self.loop.sock_connect(sock, proxy_address) |
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socks = Socks(self.loop, sock, host, port) |
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await socks.handshake() |
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return sock |
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except Exception: |
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sock.close() |
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raise |
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|
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async def detect_proxy(self, host='www.google.com', port=80, |
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log_failure=True): |
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'''Attempt to detect a proxy by establishing a connection through it |
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to the given target host / port pair. |
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''' |
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if self.is_up(): |
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return |
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|
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sock = None |
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for proxy_port in self.try_ports: |
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if proxy_port is None: |
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continue |
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paddress = (self.host, proxy_port) |
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try: |
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sock = await self.connect_via_proxy(host, port, paddress) |
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break |
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except Exception as e: |
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if log_failure: |
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self.logger.info('failed to detect proxy at {}: {}' |
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.format(util.address_string(paddress), e)) |
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self.tried_event.set() |
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# Failed all ports? |
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if sock is None: |
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return |
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peername = sock.getpeername() |
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sock.close() |
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self.ip_addr = peername[0] |
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self.port = proxy_port |
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self.errors = 0 |
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self.logger.info('detected proxy at {} ({})' |
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.format(util.address_string(paddress), self.ip_addr)) |
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|
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async def create_connection(self, protocol_factory, host, port, **kwargs): |
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'''All arguments are as to asyncio's create_connection method.''' |
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try: |
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sock = await self.connect_via_proxy(host, port) |
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self.errors = 0 |
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except Exception: |
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self.errors += 1 |
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# If we have 3 consecutive errors, consider the proxy undetected |
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if self.errors == 3: |
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self.set_lost() |
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raise |
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hostname = host if kwargs.get('ssl') else None |
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return await self.loop.create_connection( |
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protocol_factory, sock=sock, server_hostname=hostname, **kwargs) |
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