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281 lines
10 KiB
281 lines
10 KiB
#!/usr/bin/python
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# -*- coding: utf-8 -*-
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# Copyright (c) 2014 clowwindy
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#
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# Permission is hereby granted, free of charge, to any person obtaining a copy
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# of this software and associated documentation files (the "Software"), to deal
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# in the Software without restriction, including without limitation the rights
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# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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# copies of the Software, and to permit persons to whom the Software is
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# furnished to do so, subject to the following conditions:
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#
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# The above copyright notice and this permission notice shall be included in
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# 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, EXPRESS OR
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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# SOFTWARE.
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# SOCKS5 UDP Request
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# +----+------+------+----------+----------+----------+
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# |RSV | FRAG | ATYP | DST.ADDR | DST.PORT | DATA |
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# +----+------+------+----------+----------+----------+
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# | 2 | 1 | 1 | Variable | 2 | Variable |
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# +----+------+------+----------+----------+----------+
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# SOCKS5 UDP Response
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# +----+------+------+----------+----------+----------+
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# |RSV | FRAG | ATYP | DST.ADDR | DST.PORT | DATA |
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# +----+------+------+----------+----------+----------+
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# | 2 | 1 | 1 | Variable | 2 | Variable |
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# +----+------+------+----------+----------+----------+
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# shadowsocks UDP Request (before encrypted)
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# +------+----------+----------+----------+
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# | ATYP | DST.ADDR | DST.PORT | DATA |
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# +------+----------+----------+----------+
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# | 1 | Variable | 2 | Variable |
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# +------+----------+----------+----------+
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# shadowsocks UDP Response (before encrypted)
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# +------+----------+----------+----------+
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# | ATYP | DST.ADDR | DST.PORT | DATA |
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# +------+----------+----------+----------+
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# | 1 | Variable | 2 | Variable |
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# +------+----------+----------+----------+
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# shadowsocks UDP Request and Response (after encrypted)
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# +-------+--------------+
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# | IV | PAYLOAD |
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# +-------+--------------+
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# | Fixed | Variable |
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# +-------+--------------+
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# HOW TO NAME THINGS
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# ------------------
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# `dest` means destination server, which is from DST fields in the SOCKS5
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# request
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# `local` means local server of shadowsocks
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# `remote` means remote server of shadowsocks
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# `client` means UDP clients that connects to other servers
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# `server` means the UDP server that handles user requests
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import time
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import threading
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import socket
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import logging
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import struct
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import encrypt
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import eventloop
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import lru_cache
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import errno
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BUF_SIZE = 65536
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def parse_header(data):
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addrtype = ord(data[0])
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dest_addr = None
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dest_port = None
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header_length = 0
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if addrtype == 1:
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if len(data) >= 7:
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dest_addr = socket.inet_ntoa(data[1:5])
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dest_port = struct.unpack('>H', data[5:7])[0]
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header_length = 7
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else:
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logging.warn('[udp] header is too short')
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elif addrtype == 3:
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if len(data) > 2:
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addrlen = ord(data[1])
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if len(data) >= 2 + addrlen:
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dest_addr = data[2:2 + addrlen]
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dest_port = struct.unpack('>H', data[2 + addrlen:4 +
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addrlen])[0]
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header_length = 4 + addrlen
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else:
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logging.warn('[udp] header is too short')
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else:
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logging.warn('[udp] header is too short')
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elif addrtype == 4:
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if len(data) >= 19:
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dest_addr = socket.inet_ntop(socket.AF_INET6, data[1:17])
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dest_port = struct.unpack('>H', data[17:19])[0]
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header_length = 19
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else:
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logging.warn('[udp] header is too short')
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else:
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logging.warn('unsupported addrtype %d' % addrtype)
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if dest_addr is None:
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return None
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return (addrtype, dest_addr, dest_port, header_length)
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def client_key(a, b, c, d):
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return '%s:%s:%s:%s' % (a, b, c, d)
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class UDPRelay(object):
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def __init__(self, listen_addr='127.0.0.1', listen_port=1080,
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remote_addr='127.0.0.1', remote_port=8387, password=None,
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method='table', timeout=300, is_local=True):
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self._listen_addr = listen_addr
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self._listen_port = listen_port
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self._remote_addr = remote_addr
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self._remote_port = remote_port
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self._password = password
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self._method = method
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self._timeout = timeout
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self._is_local = is_local
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self._eventloop = eventloop.EventLoop()
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self._cache = lru_cache.LRUCache(timeout=timeout,
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close_callback=self._close_client)
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self._client_fd_to_server_addr = lru_cache.LRUCache(timeout=timeout)
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def _close_client(self, client):
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if hasattr(client, 'close'):
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self._eventloop.remove(client)
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client.close()
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else:
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# just an address
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pass
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def _handle_server(self):
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server = self._server_socket
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data, r_addr = server.recvfrom(BUF_SIZE)
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if self._is_local:
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frag = ord(data[2])
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if frag != 0:
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logging.warn('drop a message since frag is not 0')
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return
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else:
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data = data[3:]
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else:
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# decrypt data
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data = encrypt.encrypt_all(self._password, self._method, 0, data)
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if not data:
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return
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header_result = parse_header(data)
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if header_result is None:
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return
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addrtype, dest_addr, dest_port, header_length = header_result
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if self._is_local:
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server_addr, server_port = self._remote_addr, self._remote_port
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else:
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server_addr, server_port = dest_addr, dest_port
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key = client_key(r_addr[0], r_addr[1], dest_addr, dest_port)
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client = self._cache.get(key, None)
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if not client:
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# TODO async getaddrinfo
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addrs = socket.getaddrinfo(server_addr, server_port, 0,
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socket.SOCK_DGRAM, socket.SOL_UDP)
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if addrs:
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af, socktype, proto, canonname, sa = addrs[0]
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client = socket.socket(af, socktype, proto)
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client.setblocking(False)
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self._cache[key] = client
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self._client_fd_to_server_addr[client.fileno()] = r_addr
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else:
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# drop
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return
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self._eventloop.add(client, eventloop.POLL_IN)
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data = data[header_length:]
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if not data:
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return
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if self._is_local:
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data = encrypt.encrypt_all(self._password, self._method, 1, data)
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if not data:
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return
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try:
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client.sendto(data, (server_addr, server_port))
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except IOError as e:
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err = eventloop.errno_from_exception(e)
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if err in (errno.EINPROGRESS, errno.EAGAIN):
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pass
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else:
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logging.error(e)
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def _handle_client(self, sock):
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data, r_addr = sock.recvfrom(BUF_SIZE)
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if not self._is_local:
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addrlen = len(r_addr[0])
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if addrlen > 255:
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# drop
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return
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data = '\x03' + chr(addrlen) + r_addr[0] + \
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struct.pack('>H', r_addr[1]) + data
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response = encrypt.encrypt_all(self._password, self._method, 1,
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data)
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if not response:
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return
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else:
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data = encrypt.encrypt_all(self._password, self._method, 0,
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data)
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if not data:
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return
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header_result = parse_header(data)
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if header_result is None:
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return
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# addrtype, dest_addr, dest_port, header_length = header_result
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response = '\x00\x00\x00' + data
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client_addr = self._client_fd_to_server_addr.get(sock.fileno(), None)
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if client_addr:
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self._server_socket.sendto(response, client_addr)
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else:
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# this packet is from somewhere else we know
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# simply drop that packet
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pass
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def _run(self):
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server_socket = self._server_socket
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self._eventloop.add(server_socket, eventloop.POLL_IN)
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last_time = time.time()
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while True:
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try:
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events = self._eventloop.poll(10)
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except (OSError, IOError) as e:
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if eventloop.errno_from_exception(e) == errno.EPIPE:
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# Happens when the client closes the connection
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continue
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else:
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logging.error(e)
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continue
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for sock, event in events:
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if sock == self._server_socket:
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self._handle_server()
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else:
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self._handle_client(sock)
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now = time.time()
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if now - last_time > 3.5:
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self._cache.sweep()
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if now - last_time > 7:
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self._client_fd_to_server_addr.sweep()
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last_time = now
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def start(self):
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addrs = socket.getaddrinfo(self._listen_addr, self._listen_port, 0,
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socket.SOCK_DGRAM, socket.SOL_UDP)
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if len(addrs) == 0:
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raise Exception("can't get addrinfo for %s:%d" %
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(self._listen_addr, self._listen_port))
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af, socktype, proto, canonname, sa = addrs[0]
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server_socket = socket.socket(af, socktype, proto)
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server_socket.bind((self._listen_addr, self._listen_port))
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server_socket.setblocking(False)
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self._server_socket = server_socket
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t = threading.Thread(target=self._run)
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t.setName('UDPThread')
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t.setDaemon(True)
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t.start()
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self._thread = t
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