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290 lines
10 KiB
290 lines
10 KiB
#!/usr/bin/python
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# -*- coding: utf-8 -*-
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#
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# Copyright 2015 clowwindy
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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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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from __future__ import absolute_import, division, print_function, \
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with_statement
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import time
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import socket
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import logging
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import struct
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import errno
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import random
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from shadowsocks import encrypt, eventloop, lru_cache, common, shell
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from shadowsocks.common import parse_header, pack_addr
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BUF_SIZE = 65536
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def client_key(source_addr, server_af):
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# notice this is server af, not dest af
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return '%s:%s:%d' % (source_addr[0], source_addr[1], server_af)
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class UDPRelay(object):
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def __init__(self, config, dns_resolver, is_local):
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self._config = config
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if is_local:
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self._listen_addr = config['local_address']
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self._listen_port = config['local_port']
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self._remote_addr = config['server']
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self._remote_port = config['server_port']
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else:
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self._listen_addr = config['server']
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self._listen_port = config['server_port']
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self._remote_addr = None
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self._remote_port = None
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self._dns_resolver = dns_resolver
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self._password = config['password']
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self._method = config['method']
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self._timeout = config['timeout']
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self._is_local = is_local
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self._cache = lru_cache.LRUCache(timeout=config['timeout'],
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close_callback=self._close_client)
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self._client_fd_to_server_addr = \
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lru_cache.LRUCache(timeout=config['timeout'])
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self._dns_cache = lru_cache.LRUCache(timeout=300)
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self._eventloop = None
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self._closed = False
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self._last_time = time.time()
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self._sockets = set()
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if 'forbidden_ip' in config:
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self._forbidden_iplist = config['forbidden_ip']
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else:
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self._forbidden_iplist = None
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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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def _get_a_server(self):
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server = self._config['server']
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server_port = self._config['server_port']
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if type(server_port) == list:
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server_port = random.choice(server_port)
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if type(server) == list:
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server = random.choice(server)
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logging.debug('chosen server: %s:%d', server, server_port)
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return server, server_port
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def _close_client(self, client):
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if hasattr(client, 'close'):
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self._sockets.remove(client.fileno())
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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 not data:
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logging.debug('UDP handle_server: data is empty')
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if self._is_local:
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frag = common.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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data = encrypt.encrypt_all(self._password, self._method, 0, data)
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# decrypt data
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if not data:
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logging.debug('UDP handle_server: data is empty after decrypt')
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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._get_a_server()
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else:
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server_addr, server_port = dest_addr, dest_port
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addrs = self._dns_cache.get(server_addr, None)
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if addrs is None:
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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 not addrs:
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# drop
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return
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else:
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self._dns_cache[server_addr] = addrs
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af, socktype, proto, canonname, sa = addrs[0]
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key = client_key(r_addr, af)
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logging.debug(key)
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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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if self._forbidden_iplist:
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if common.to_str(sa[0]) in self._forbidden_iplist:
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logging.debug('IP %s is in forbidden list, drop' %
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common.to_str(sa[0]))
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# drop
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return
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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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self._sockets.add(client.fileno())
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self._eventloop.add(client, eventloop.POLL_IN)
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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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else:
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data = data[header_length:]
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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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shell.print_exception(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 data:
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logging.debug('UDP handle_client: data is empty')
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return
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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 = pack_addr(r_addr[0]) + 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 = b'\x00\x00\x00' + data
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client_addr = self._client_fd_to_server_addr.get(sock.fileno())
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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 add_to_loop(self, loop):
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if self._eventloop:
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raise Exception('already add to loop')
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if self._closed:
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raise Exception('already closed')
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self._eventloop = loop
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loop.add_handler(self._handle_events)
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server_socket = self._server_socket
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self._eventloop.add(server_socket,
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eventloop.POLL_IN | eventloop.POLL_ERR)
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def _handle_events(self, events):
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for sock, fd, event in events:
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if sock == self._server_socket:
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if event & eventloop.POLL_ERR:
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logging.error('UDP server_socket err')
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self._handle_server()
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elif sock and (fd in self._sockets):
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if event & eventloop.POLL_ERR:
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logging.error('UDP client_socket err')
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self._handle_client(sock)
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now = time.time()
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if now - self._last_time > 3:
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self._cache.sweep()
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self._client_fd_to_server_addr.sweep()
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self._last_time = now
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if self._closed:
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self._server_socket.close()
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for sock in self._sockets:
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sock.close()
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self._eventloop.remove_handler(self._handle_events)
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def close(self, next_tick=False):
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self._closed = True
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if not next_tick:
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self._server_socket.close()
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