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youtube-dl/youtube_dl/socks.py
Yen Chi Hsuan 4bd7d9d4ae
[socks] Refine exception model for better error handling
1. ProxyError now inherits from socket.error instead of IOError

The only functions socks.py overrides are connect and connect_ex. In
Python 2.x and Python <= 3.2, socket functions raises socket.error. In
newer Python versions, those functions raises OSError instead. The name
socket.error is preserved as an alias of OSError for backward
compability. To keep socks.py compatible with Python's standard library,
it should raise the same exception as raw sockets.

See PEP 3151 (https://www.python.org/dev/peps/pep-3151/) for more
information about the change in Python 3.3.

2. Raise EOFError instead of IOError when the socket receives less data
than it expects

There's no common convention, but both ftplib and telnetlib raises
EOFError for similar situations. socks.py follows them.

Closes #11355

In #11355, only Python 2 is affected. In Python 3, both socket.error and
IOError are alias of OSError, so AbstractHTTPHandler.do_open correctly
catches the error and thus InfoExtractor._is_valid_url works fine.
2016-12-05 00:43:37 +08:00

272 lines
8.5 KiB
Python

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