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[socks] Eliminate magic constants and improve

This commit is contained in:
Yen Chi Hsuan 2016-05-03 15:11:05 +08:00
parent 72f3289ac4
commit 9e9cd7248d
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@ -3,37 +3,87 @@
from __future__ import unicode_literals 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 collections
import socket import socket
from .compat import ( from .compat import (
compat_ord,
struct_pack, struct_pack,
struct_unpack, struct_unpack,
) )
__author__ = 'Timo Schmid <coding@timoschmid.de>' __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 = 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(IOError): class ProxyError(IOError):
pass ERR_SUCCESS = 0x00
class Socks4Error(ProxyError):
CODES = {
0x5B: 'request rejected or failed',
0x5C: 'request rejected becasue SOCKS server cannot connect to identd on the client',
0x5D: 'request rejected because the client program and identd report different user-ids'
}
def __init__(self, code=None, msg=None): def __init__(self, code=None, msg=None):
if code is not None and msg is None: if code is not None and msg is None:
msg = self.CODES.get(code) msg = self.CODES.get(code) and 'unknown error'
if msg is None: super(ProxyError, self).__init__(code, msg)
msg = 'unknown error'
super(Socks4Error, self).__init__(code, msg)
class Socks5Error(Socks4Error): 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 becasue 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 = { CODES = {
0x01: 'general SOCKS server failure', 0x01: 'general SOCKS server failure',
0x02: 'connection not allowed by ruleset', 0x02: 'connection not allowed by ruleset',
@ -53,27 +103,19 @@ class ProxyType(object):
SOCKS4A = 1 SOCKS4A = 1
SOCKS5 = 2 SOCKS5 = 2
Proxy = collections.namedtuple('Proxy', ('type', 'host', 'port', 'username', 'password', 'remote_dns')) Proxy = collections.namedtuple('Proxy', (
'type', 'host', 'port', 'username', 'password', 'remote_dns'))
class sockssocket(socket.socket): class sockssocket(socket.socket):
@property def __init__(self, *args, **kwargs):
def _proxy(self): self._proxy = None
return self.__proxy super(sockssocket, self).__init__(*args, **kwargs)
@property def setproxy(self, proxytype, addr, port, rdns=True, username=None, password=None):
def _proxy_port(self): assert proxytype in (ProxyType.SOCKS4, ProxyType.SOCKS4A, ProxyType.SOCKS5)
if self._proxy:
if self._proxy.port:
return self._proxy.port
return 1080
return None
def setproxy(self, proxytype=None, addr=None, port=None, rdns=True, username=None, password=None): self._proxy = Proxy(proxytype, addr, port, username, password, rdns)
if proxytype is None:
self.__proxy = None
else:
self.__proxy = Proxy(proxytype, addr, port, username, password, rdns)
def recvall(self, cnt): def recvall(self, cnt):
data = b'' data = b''
@ -84,163 +126,146 @@ class sockssocket(socket.socket):
data += cur data += cur
return data return data
def _recv_bytes(self, cnt):
data = self.recvall(cnt)
return struct_unpack('!{0}B'.format(cnt), data)
@staticmethod
def _len_and_data(data):
return 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): def _setup_socks4(self, address, is_4a=False):
destaddr, port = address destaddr, port = address
try: ipaddr = self._resolve_address(destaddr, SOCKS4_DEFAULT_DSTIP, use_remote_dns=is_4a)
ipaddr = socket.inet_aton(destaddr)
except socket.error:
if is_4a and self._proxy.remote_dns:
ipaddr = struct_pack('!BBBB', 0, 0, 0, 0xFF)
else:
ipaddr = socket.inet_aton(socket.gethostbyname(destaddr))
packet = struct_pack('!BBH', 0x4, 0x1, port) + ipaddr packet = struct_pack('!BBH', SOCKS4_VERSION, Socks4Command.CMD_CONNECT, port) + ipaddr
if self._proxy.username:
username = self._proxy.username username = (self._proxy.username or '').encode('utf-8')
if hasattr(username, 'encode'): packet += username + b'\x00'
username = username.encode()
packet += struct_pack('!{0}s'.format(len(username) + 1), username)
else:
packet += b'\x00'
if is_4a and self._proxy.remote_dns: if is_4a and self._proxy.remote_dns:
if hasattr(destaddr, 'encode'): packet += destaddr.encode('utf-8') + b'\x00'
destaddr = destaddr.encode()
packet += struct_pack('!{0}s'.format(len(destaddr) + 1), destaddr)
self.sendall(packet) self.sendall(packet)
packet = self.recvall(8) version, resp_code, dstport, dsthost = struct_unpack('!BBHI', self.recvall(8))
nbyte, resp_code, dstport, dsthost = struct_unpack('!BBHI', packet)
# check valid response self._check_response_version(SOCKS4_REPLY_VERSION, version)
if nbyte != 0x00:
self.close()
raise ProxyError(
0, 'Invalid response from server. Expected {0:02x} got {1:02x}'.format(0, nbyte))
# access granted if resp_code != Socks4Error.ERR_SUCCESS:
if resp_code != 0x5a:
self.close() self.close()
raise Socks4Error(resp_code) raise Socks4Error(resp_code)
return (dsthost, dstport) return (dsthost, dstport)
def _setup_socks5(self, address): def _setup_socks4a(self, address):
destaddr, port = address self._setup_socks4(address, is_4a=True)
try: def _socks5_auth(self):
ipaddr = socket.inet_aton(destaddr) packet = struct_pack('!B', SOCKS5_VERSION)
except socket.error:
if self._proxy.remote_dns:
ipaddr = None
else:
ipaddr = socket.inet_aton(socket.gethostbyname(destaddr))
auth_methods = 1 auth_methods = [Socks5Auth.AUTH_NONE]
if self._proxy.username and self._proxy.password: if self._proxy.username and self._proxy.password:
# two auth methods available auth_methods.append(Socks5Auth.AUTH_USER_PASS)
auth_methods = 2
packet = struct_pack('!BBB', 0x5, auth_methods, 0x00) # no auth packet += struct_pack('!B', len(auth_methods))
if self._proxy.username and self._proxy.password: packet += struct_pack('!{0}B'.format(len(auth_methods)), *auth_methods)
packet += struct_pack('!B', 0x02) # user/pass auth
self.sendall(packet) self.sendall(packet)
packet = self.recvall(2) version, method = self._recv_bytes(2)
version, method = struct_unpack('!BB', packet)
# check valid response self._check_response_version(SOCKS5_VERSION, version)
if version != 0x05:
self.close()
raise ProxyError(
0, 'Invalid response from server. Expected {0:02x} got {1:02x}'.format(5, version))
# no auth methods if method == Socks5Auth.AUTH_NO_ACCEPTABLE:
if method == 0xFF:
self.close() self.close()
raise Socks5Error(method) raise Socks5Error(method)
# user/pass auth if method == Socks5Auth.AUTH_USER_PASS:
if method == 0x01: username = self._proxy.username.encode('utf-8')
username = self._proxy.username password = self._proxy.password.encode('utf-8')
if hasattr(username, 'encode'): packet = struct_pack('!B', SOCKS5_USER_AUTH_VERSION)
username = username.encode() packet += self._len_and_data(username) + self._len_and_data(password)
password = self._proxy.password
if hasattr(password, 'encode'):
password = password.encode()
packet = struct_pack('!BB', 1, len(username)) + username
packet += struct_pack('!B', len(password)) + password
self.sendall(packet) self.sendall(packet)
packet = self.recvall(2) version, status = self._recv_bytes(2)
version, status = struct_unpack('!BB', packet)
if version != 0x01: self._check_response_version(SOCKS5_USER_AUTH_VERSION, version)
self.close()
raise ProxyError(
0, 'Invalid response from server. Expected {0:02x} got {1:02x}'.format(1, version))
if status != 0x00: if status != SOCKS5_USER_AUTH_SUCCESS:
self.close() self.close()
raise Socks5Error(1) raise Socks5Error(Socks5Error.ERR_GENERAL_FAILURE)
elif method == 0x00: # no auth elif method == Socks5Auth.AUTH_NONE:
pass pass
packet = struct_pack('!BBB', 5, 1, 0) def _setup_socks5(self, address):
destaddr, port = address
ipaddr = self._resolve_address(destaddr, None, use_remote_dns=True)
self._socks5_auth()
reserved = 0
packet = struct_pack('!BBB', SOCKS5_VERSION, Socks5Command.CMD_CONNECT, reserved)
if ipaddr is None: if ipaddr is None:
if hasattr(destaddr, 'encode'): destaddr = destaddr.encode('utf-8')
destaddr = destaddr.encode() packet += struct_pack('!B', Socks5AddressType.ATYP_DOMAINNAME)
packet += struct_pack('!BB', 3, len(destaddr)) + destaddr packet += self._len_and_data(destaddr)
else: else:
packet += struct_pack('!B', 1) + ipaddr packet += struct_pack('!B', Socks5AddressType.ATYP_IPV4) + ipaddr
packet += struct_pack('!H', port) packet += struct_pack('!H', port)
self.sendall(packet) self.sendall(packet)
packet = self.recvall(4) version, status, reserved, atype = self._recv_bytes(4)
version, status, _, atype = struct_unpack('!BBBB', packet)
if version != 0x05: self._check_response_version(SOCKS5_VERSION, version)
self.close()
raise ProxyError(
0, 'Invalid response from server. Expected {0:02x} got {1:02x}'.format(5, version))
if status != 0x00: if status != Socks5Error.ERR_SUCCESS:
self.close() self.close()
raise Socks5Error(status) raise Socks5Error(status)
if atype == 0x01: if atype == Socks5AddressType.ATYP_IPV4:
destaddr = self.recvall(4) destaddr = self.recvall(4)
elif atype == 0x03: elif atype == Socks5AddressType.ATYP_DOMAINNAME:
alen = struct_unpack('!B', self.recv(1))[0] alen = compat_ord(self.recv(1))
destaddr = self.recvall(alen) destaddr = self.recvall(alen)
elif atype == 0x04: elif atype == Socks5AddressType.ATYP_IPV6:
destaddr = self.recvall(16) destaddr = self.recvall(16)
destport = struct_unpack('!H', self.recvall(2))[0] destport = struct_unpack('!H', self.recvall(2))[0]
return (destaddr, destport) return (destaddr, destport)
def _make_proxy(self, connect_func, address): def _make_proxy(self, connect_func, address):
if self._proxy.type == ProxyType.SOCKS4: if not self._proxy:
result = connect_func(self, (self._proxy.host, self._proxy_port))
if result != 0 and result is not None:
return result
self._setup_socks4(address)
elif self._proxy.type == ProxyType.SOCKS4A:
result = connect_func(self, (self._proxy.host, self._proxy_port))
if result != 0 and result is not None:
return result
self._setup_socks4(address, is_4a=True)
elif self._proxy.type == ProxyType.SOCKS5:
result = connect_func(self, (self._proxy.host, self._proxy_port))
if result != 0 and result is not None:
return result
self._setup_socks5(address)
else:
return connect_func(self, address) 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): def connect(self, address):
self._make_proxy(socket.socket.connect, address) self._make_proxy(socket.socket.connect, address)