shadowsocks/shadowsocks/tcprelay.py
2014-08-27 00:17:26 +08:00

637 lines
25 KiB
Python

#!/usr/bin/python
# -*- coding: utf-8 -*-
# Copyright (c) 2014 clowwindy
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
import time
import socket
import errno
import struct
import logging
import traceback
import random
import encrypt
import eventloop
import utils
from common import parse_header
TIMEOUTS_CLEAN_SIZE = 512
TIMEOUT_PRECISION = 4
MSG_FASTOPEN = 0x20000000
CMD_CONNECT = 1
CMD_BIND = 2
CMD_UDP_ASSOCIATE = 3
# local:
# stage 0 init
# stage 1 hello received, hello sent
# stage 2 UDP assoc
# stage 3 DNS
# stage 4 addr received, reply sent
# stage 5 remote connected
# remote:
# stage 0 init
# stage 3 DNS
# stage 4 addr received, reply sent
# stage 5 remote connected
STAGE_INIT = 0
STAGE_HELLO = 1
STAGE_UDP_ASSOC = 2
STAGE_DNS = 3
STAGE_REPLY = 4
STAGE_STREAM = 5
STAGE_DESTROYED = -1
# stream direction
STREAM_UP = 0
STREAM_DOWN = 1
# stream wait status
WAIT_STATUS_INIT = 0
WAIT_STATUS_READING = 1
WAIT_STATUS_WRITING = 2
WAIT_STATUS_READWRITING = WAIT_STATUS_READING | WAIT_STATUS_WRITING
BUF_SIZE = 32 * 1024
class TCPRelayHandler(object):
def __init__(self, server, fd_to_handlers, loop, local_sock, config,
dns_resolver, is_local):
self._server = server
self._fd_to_handlers = fd_to_handlers
self._loop = loop
self._local_sock = local_sock
self._remote_sock = None
self._config = config
self._dns_resolver = dns_resolver
self._is_local = is_local
self._stage = STAGE_INIT
self._encryptor = encrypt.Encryptor(config['password'],
config['method'])
self._fastopen_connected = False
self._data_to_write_to_local = []
self._data_to_write_to_remote = []
self._upstream_status = WAIT_STATUS_READING
self._downstream_status = WAIT_STATUS_INIT
self._remote_address = None
if is_local:
self._chosen_server = self._get_a_server()
fd_to_handlers[local_sock.fileno()] = self
local_sock.setblocking(False)
local_sock.setsockopt(socket.SOL_TCP, socket.TCP_NODELAY, 1)
loop.add(local_sock, eventloop.POLL_IN | eventloop.POLL_ERR)
self.last_activity = 0
self._update_activity()
def __hash__(self):
# default __hash__ is id / 16
# we want to eliminate collisions
return id(self)
@property
def remote_address(self):
return self._remote_address
def _get_a_server(self):
server = self._config['server']
server_port = self._config['server_port']
if type(server_port) == list:
server_port = random.choice(server_port)
logging.debug('chosen server: %s:%d', server, server_port)
# TODO support multiple server IP
return server, server_port
def _update_activity(self):
self._server.update_activity(self)
def _update_stream(self, stream, status):
dirty = False
if stream == STREAM_DOWN:
if self._downstream_status != status:
self._downstream_status = status
dirty = True
elif stream == STREAM_UP:
if self._upstream_status != status:
self._upstream_status = status
dirty = True
if dirty:
if self._local_sock:
event = eventloop.POLL_ERR
if self._downstream_status & WAIT_STATUS_WRITING:
event |= eventloop.POLL_OUT
if self._upstream_status & WAIT_STATUS_READING:
event |= eventloop.POLL_IN
self._loop.modify(self._local_sock, event)
if self._remote_sock:
event = eventloop.POLL_ERR
if self._downstream_status & WAIT_STATUS_READING:
event |= eventloop.POLL_IN
if self._upstream_status & WAIT_STATUS_WRITING:
event |= eventloop.POLL_OUT
self._loop.modify(self._remote_sock, event)
def _write_to_sock(self, data, sock):
if not data or not sock:
return False
uncomplete = False
try:
l = len(data)
s = sock.send(data)
if s < l:
data = data[s:]
uncomplete = True
except (OSError, IOError) as e:
error_no = eventloop.errno_from_exception(e)
if error_no in (errno.EAGAIN, errno.EINPROGRESS,
errno.EWOULDBLOCK):
uncomplete = True
else:
logging.error(e)
if self._config['verbose']:
traceback.print_exc()
self.destroy()
return False
if uncomplete:
if sock == self._local_sock:
self._data_to_write_to_local.append(data)
self._update_stream(STREAM_DOWN, WAIT_STATUS_WRITING)
elif sock == self._remote_sock:
self._data_to_write_to_remote.append(data)
self._update_stream(STREAM_UP, WAIT_STATUS_WRITING)
else:
logging.error('write_all_to_sock:unknown socket')
else:
if sock == self._local_sock:
self._update_stream(STREAM_DOWN, WAIT_STATUS_READING)
elif sock == self._remote_sock:
self._update_stream(STREAM_UP, WAIT_STATUS_READING)
else:
logging.error('write_all_to_sock:unknown socket')
return True
def _handle_stage_reply(self, data):
if self._is_local:
data = self._encryptor.encrypt(data)
self._data_to_write_to_remote.append(data)
if self._is_local and not self._fastopen_connected and \
self._config['fast_open']:
try:
self._fastopen_connected = True
remote_sock = \
self._create_remote_socket(self._chosen_server[0],
self._chosen_server[1])
self._loop.add(remote_sock, eventloop.POLL_ERR)
data = ''.join(self._data_to_write_to_local)
l = len(data)
s = remote_sock.sendto(data, MSG_FASTOPEN, self._chosen_server)
if s < l:
data = data[s:]
self._data_to_write_to_local = [data]
self._update_stream(STREAM_UP, WAIT_STATUS_READWRITING)
else:
self._data_to_write_to_local = []
self._update_stream(STREAM_UP, WAIT_STATUS_READING)
self._stage = STAGE_STREAM
except (OSError, IOError) as e:
if eventloop.errno_from_exception(e) == errno.EINPROGRESS:
self._update_stream(STREAM_UP, WAIT_STATUS_READWRITING)
elif eventloop.errno_from_exception(e) == errno.ENOTCONN:
logging.error('fast open not supported on this OS')
self._config['fast_open'] = False
self.destroy()
else:
logging.error(e)
if self._config['verbose']:
traceback.print_exc()
self.destroy()
def _handle_stage_hello(self, data):
try:
if self._is_local:
cmd = ord(data[1])
if cmd == CMD_UDP_ASSOCIATE:
logging.debug('UDP associate')
if self._local_sock.family == socket.AF_INET6:
header = '\x05\x00\x00\x04'
else:
header = '\x05\x00\x00\x01'
addr, port = self._local_sock.getsockname()
addr_to_send = socket.inet_pton(self._local_sock.family,
addr)
port_to_send = struct.pack('>H', port)
self._write_to_sock(header + addr_to_send + port_to_send,
self._local_sock)
self._stage = STAGE_UDP_ASSOC
# just wait for the client to disconnect
return
elif cmd == CMD_CONNECT:
# just trim VER CMD RSV
data = data[3:]
else:
logging.error('unknown command %d', cmd)
self.destroy()
return
header_result = parse_header(data)
if header_result is None:
raise Exception('can not parse header')
addrtype, remote_addr, remote_port, header_length = header_result
logging.info('connecting %s:%d' % (remote_addr, remote_port))
self._remote_address = (remote_addr, remote_port)
# pause reading
self._update_stream(STREAM_UP, WAIT_STATUS_WRITING)
self._stage = STAGE_DNS
if self._is_local:
# forward address to remote
self._write_to_sock('\x05\x00\x00\x01\x00\x00\x00\x00\x10\x10',
self._local_sock)
data_to_send = self._encryptor.encrypt(data)
self._data_to_write_to_remote.append(data_to_send)
# notice here may go into _handle_dns_resolved directly
self._dns_resolver.resolve(self._chosen_server[0],
self._handle_dns_resolved)
else:
if len(data) > header_length:
self._data_to_write_to_remote.append(data[header_length:])
# notice here may go into _handle_dns_resolved directly
self._dns_resolver.resolve(remote_addr,
self._handle_dns_resolved)
except Exception as e:
logging.error(e)
if self._config['verbose']:
traceback.print_exc()
# TODO use logging when debug completed
self.destroy()
def _create_remote_socket(self, ip, port):
addrs = socket.getaddrinfo(ip, port, 0, socket.SOCK_STREAM,
socket.SOL_TCP)
if len(addrs) == 0:
raise Exception("getaddrinfo failed for %s:%d" % (ip, port))
af, socktype, proto, canonname, sa = addrs[0]
remote_sock = socket.socket(af, socktype, proto)
self._remote_sock = remote_sock
self._fd_to_handlers[remote_sock.fileno()] = self
remote_sock.setblocking(False)
remote_sock.setsockopt(socket.SOL_TCP, socket.TCP_NODELAY, 1)
return remote_sock
def _handle_dns_resolved(self, result, error):
if error:
logging.error(error)
self.destroy()
return
if result:
ip = result[1]
if ip:
try:
self._stage = STAGE_REPLY
remote_addr = ip
if self._is_local:
remote_port = self._chosen_server[1]
else:
remote_port = self._remote_address[1]
if self._is_local and self._config['fast_open']:
# wait for more data to arrive and send them in one SYN
self._stage = STAGE_REPLY
self._update_stream(STREAM_UP, WAIT_STATUS_READING)
# TODO when there is already data in this packet
else:
remote_sock = self._create_remote_socket(remote_addr,
remote_port)
try:
remote_sock.connect((remote_addr, remote_port))
except (OSError, IOError) as e:
if eventloop.errno_from_exception(e) == \
errno.EINPROGRESS:
pass
self._loop.add(remote_sock,
eventloop.POLL_ERR | eventloop.POLL_OUT)
self._stage = STAGE_REPLY
self._update_stream(STREAM_UP, WAIT_STATUS_READWRITING)
self._update_stream(STREAM_DOWN, WAIT_STATUS_READING)
return
except (OSError, IOError) as e:
logging.error(e)
if self._config['verbose']:
traceback.print_exc()
self.destroy()
def _on_local_read(self):
self._update_activity()
if not self._local_sock:
return
is_local = self._is_local
data = None
try:
data = self._local_sock.recv(BUF_SIZE)
except (OSError, IOError) as e:
if eventloop.errno_from_exception(e) in \
(errno.ETIMEDOUT, errno.EAGAIN, errno.EWOULDBLOCK):
return
if not data:
self.destroy()
return
if not is_local:
data = self._encryptor.decrypt(data)
if not data:
return
if self._stage == STAGE_STREAM:
if self._is_local:
data = self._encryptor.encrypt(data)
self._write_to_sock(data, self._remote_sock)
return
elif is_local and self._stage == STAGE_INIT:
# TODO check auth method
self._write_to_sock('\x05\00', self._local_sock)
self._stage = STAGE_HELLO
return
elif self._stage == STAGE_REPLY:
self._handle_stage_reply(data)
elif (is_local and self._stage == STAGE_HELLO) or \
(not is_local and self._stage == STAGE_INIT):
self._handle_stage_hello(data)
def _on_remote_read(self):
self._update_activity()
data = None
try:
data = self._remote_sock.recv(BUF_SIZE)
except (OSError, IOError) as e:
if eventloop.errno_from_exception(e) in \
(errno.ETIMEDOUT, errno.EAGAIN, errno.EWOULDBLOCK):
return
if not data:
self.destroy()
return
if self._is_local:
data = self._encryptor.decrypt(data)
else:
data = self._encryptor.encrypt(data)
try:
self._write_to_sock(data, self._local_sock)
except Exception as e:
logging.error(e)
if self._config['verbose']:
traceback.print_exc()
# TODO use logging when debug completed
self.destroy()
def _on_local_write(self):
if self._data_to_write_to_local:
data = ''.join(self._data_to_write_to_local)
self._data_to_write_to_local = []
self._write_to_sock(data, self._local_sock)
else:
self._update_stream(STREAM_DOWN, WAIT_STATUS_READING)
def _on_remote_write(self):
self._stage = STAGE_STREAM
if self._data_to_write_to_remote:
data = ''.join(self._data_to_write_to_remote)
self._data_to_write_to_remote = []
self._write_to_sock(data, self._remote_sock)
else:
self._update_stream(STREAM_UP, WAIT_STATUS_READING)
def _on_local_error(self):
logging.debug('got local error')
if self._local_sock:
logging.error(eventloop.get_sock_error(self._local_sock))
self.destroy()
def _on_remote_error(self):
logging.debug('got remote error')
if self._remote_sock:
logging.error(eventloop.get_sock_error(self._remote_sock))
self.destroy()
def handle_event(self, sock, event):
if self._stage == STAGE_DESTROYED:
logging.debug('ignore handle_event: destroyed')
return
# order is important
if sock == self._remote_sock:
if event & eventloop.POLL_ERR:
self._on_remote_error()
if self._stage == STAGE_DESTROYED:
return
if event & (eventloop.POLL_IN | eventloop.POLL_HUP):
self._on_remote_read()
if self._stage == STAGE_DESTROYED:
return
if event & eventloop.POLL_OUT:
self._on_remote_write()
elif sock == self._local_sock:
if event & eventloop.POLL_ERR:
self._on_local_error()
if self._stage == STAGE_DESTROYED:
return
if event & (eventloop.POLL_IN | eventloop.POLL_HUP):
self._on_local_read()
if self._stage == STAGE_DESTROYED:
return
if event & eventloop.POLL_OUT:
self._on_local_write()
else:
logging.warn('unknown socket')
def destroy(self):
if self._stage == STAGE_DESTROYED:
logging.debug('already destroyed')
return
self._stage = STAGE_DESTROYED
if self._remote_address:
logging.debug('destroy: %s:%d' %
self._remote_address)
else:
logging.debug('destroy')
if self._remote_sock:
logging.debug('destroying remote')
self._loop.remove(self._remote_sock)
del self._fd_to_handlers[self._remote_sock.fileno()]
self._remote_sock.close()
self._remote_sock = None
if self._local_sock:
logging.debug('destroying local')
self._loop.remove(self._local_sock)
del self._fd_to_handlers[self._local_sock.fileno()]
self._local_sock.close()
self._local_sock = None
self._dns_resolver.remove_callback(self._handle_dns_resolved)
self._server.remove_handler(self)
class TCPRelay(object):
def __init__(self, config, dns_resolver, is_local):
self._config = config
self._is_local = is_local
self._dns_resolver = dns_resolver
self._closed = False
self._eventloop = None
self._fd_to_handlers = {}
self._last_time = time.time()
self._timeout = config['timeout']
self._timeouts = [] # a list for all the handlers
# we trim the timeouts once a while
self._timeout_offset = 0 # last checked position for timeout
self._handler_to_timeouts = {} # key: handler value: index in timeouts
if is_local:
listen_addr = config['local_address']
listen_port = config['local_port']
else:
listen_addr = config['server']
listen_port = config['server_port']
addrs = socket.getaddrinfo(listen_addr, listen_port, 0,
socket.SOCK_STREAM, socket.SOL_TCP)
if len(addrs) == 0:
raise Exception("can't get addrinfo for %s:%d" %
(listen_addr, listen_port))
af, socktype, proto, canonname, sa = addrs[0]
server_socket = socket.socket(af, socktype, proto)
server_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
server_socket.bind(sa)
server_socket.setblocking(False)
if config['fast_open']:
try:
server_socket.setsockopt(socket.SOL_TCP, 23, 5)
except socket.error:
logging.error('warning: fast open is not available')
self._config['fast_open'] = False
server_socket.listen(1024)
self._server_socket = server_socket
def add_to_loop(self, loop):
if self._eventloop:
raise Exception('already add to loop')
if self._closed:
raise Exception('already closed')
self._eventloop = loop
loop.add_handler(self._handle_events)
self._eventloop.add(self._server_socket,
eventloop.POLL_IN | eventloop.POLL_ERR)
def remove_handler(self, handler):
index = self._handler_to_timeouts.get(hash(handler), -1)
if index >= 0:
# delete is O(n), so we just set it to None
self._timeouts[index] = None
del self._handler_to_timeouts[hash(handler)]
def update_activity(self, handler):
""" set handler to active """
now = int(time.time())
if now - handler.last_activity < TIMEOUT_PRECISION:
# thus we can lower timeout modification frequency
return
handler.last_activity = now
index = self._handler_to_timeouts.get(hash(handler), -1)
if index >= 0:
# delete is O(n), so we just set it to None
self._timeouts[index] = None
length = len(self._timeouts)
self._timeouts.append(handler)
self._handler_to_timeouts[hash(handler)] = length
def _sweep_timeout(self):
# tornado's timeout memory management is more flexible than we need
# we just need a sorted last_activity queue and it's faster than heapq
# in fact we can do O(1) insertion/remove so we invent our own
if self._timeouts:
logging.log(utils.VERBOSE_LEVEL, 'sweeping timeouts')
now = time.time()
length = len(self._timeouts)
pos = self._timeout_offset
while pos < length:
handler = self._timeouts[pos]
if handler:
if now - handler.last_activity < self._timeout:
break
else:
if handler.remote_address:
logging.warn('timed out: %s:%d' %
handler.remote_address)
else:
logging.warn('timed out')
handler.destroy()
self._timeouts[pos] = None # free memory
pos += 1
else:
pos += 1
if pos > TIMEOUTS_CLEAN_SIZE and pos > length >> 1:
# clean up the timeout queue when it gets larger than half
# of the queue
self._timeouts = self._timeouts[pos:]
for key in self._handler_to_timeouts:
self._handler_to_timeouts[key] -= pos
pos = 0
self._timeout_offset = pos
def _handle_events(self, events):
for sock, fd, event in events:
if sock:
logging.log(utils.VERBOSE_LEVEL, 'fd %d %s', fd,
eventloop.EVENT_NAMES.get(event, event))
if sock == self._server_socket:
if event & eventloop.POLL_ERR:
# TODO
raise Exception('server_socket error')
try:
logging.debug('accept')
conn = self._server_socket.accept()
TCPRelayHandler(self, self._fd_to_handlers,
self._eventloop, conn[0], self._config,
self._dns_resolver, self._is_local)
except (OSError, IOError) as e:
error_no = eventloop.errno_from_exception(e)
if error_no in (errno.EAGAIN, errno.EINPROGRESS,
errno.EWOULDBLOCK):
continue
else:
logging.error(e)
if self._config['verbose']:
traceback.print_exc()
else:
if sock:
handler = self._fd_to_handlers.get(fd, None)
if handler:
handler.handle_event(sock, event)
else:
logging.warn('poll removed fd')
now = time.time()
if now - self._last_time > TIMEOUT_PRECISION:
self._sweep_timeout()
self._last_time = now
def close(self):
self._closed = True
self._server_socket.close()