Reference client for Bitmessage: a P2P encrypted decentralised communication protocol:
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"""
src/network/socks5.py
=====================
"""
# pylint: disable=attribute-defined-outside-init
import socket
import struct
from proxy import GeneralProxyError, Proxy, ProxyError
class Socks5AuthError(ProxyError):
"""Rised when the socks5 protocol encounters an authentication error"""
errorCodes = (
"Succeeded",
"Authentication is required",
"All offered authentication methods were rejected",
"Unknown username or invalid password",
"Unknown error"
)
class Socks5Error(ProxyError):
"""Rised when socks5 protocol encounters an error"""
errorCodes = (
"Succeeded",
"General SOCKS server failure",
"Connection not allowed by ruleset",
"Network unreachable",
"Host unreachable",
"Connection refused",
"TTL expired",
"Command not supported",
"Address type not supported",
"Unknown error"
)
class Socks5(Proxy):
"""A socks5 proxy base class"""
def __init__(self, address=None):
Proxy.__init__(self, address)
self.ipaddr = None
self.destport = address[1]
def state_init(self):
"""Protocol initialization (before connection is established)"""
if self._auth:
self.append_write_buf(struct.pack('BBBB', 0x05, 0x02, 0x00, 0x02))
else:
self.append_write_buf(struct.pack('BBB', 0x05, 0x01, 0x00))
self.set_state("auth_1", length=0, expectBytes=2)
return True
def state_auth_1(self):
"""Perform authentication if peer is requesting it."""
ret = struct.unpack('BB', self.read_buf[:2])
if ret[0] != 5:
# general error
raise GeneralProxyError(1)
elif ret[1] == 0:
# no auth required
self.set_state("auth_done", length=2)
elif ret[1] == 2:
# username/password
self.append_write_buf(
struct.pack(
'BB', 1, len(self._auth[0])) + self._auth[0] + struct.pack(
'B', len(self._auth[1])) + self._auth[1])
self.set_state("auth_needed", length=2, expectBytes=2)
else:
if ret[1] == 0xff:
# auth error
raise Socks5AuthError(2)
else:
# other error
raise GeneralProxyError(1)
return True
def state_auth_needed(self):
"""Handle response to authentication attempt"""
ret = struct.unpack('BB', self.read_buf[0:2])
if ret[0] != 1:
# general error
raise GeneralProxyError(1)
if ret[1] != 0:
# auth error
raise Socks5AuthError(3)
# all ok
self.set_state("auth_done", length=2)
return True
def state_pre_connect(self):
"""Handle feedback from socks5 while it is connecting on our behalf."""
# Get the response
if self.read_buf[0:1] != chr(0x05).encode():
self.close()
raise GeneralProxyError(1)
elif self.read_buf[1:2] != chr(0x00).encode():
# Connection failed
self.close()
if ord(self.read_buf[1:2]) <= 8:
raise Socks5Error(ord(self.read_buf[1:2]))
else:
raise Socks5Error(9)
# Get the bound address/port
elif self.read_buf[3:4] == chr(0x01).encode():
self.set_state("proxy_addr_1", length=4, expectBytes=4)
elif self.read_buf[3:4] == chr(0x03).encode():
self.set_state("proxy_addr_2_1", length=4, expectBytes=1)
else:
self.close()
raise GeneralProxyError(1)
return True
def state_proxy_addr_1(self):
"""Handle IPv4 address returned for peer"""
self.boundaddr = self.read_buf[0:4]
self.set_state("proxy_port", length=4, expectBytes=2)
return True
def state_proxy_addr_2_1(self):
"""
Handle other addresses than IPv4 returned for peer
(e.g. IPv6, onion, ...). This is part 1 which retrieves the
length of the data.
"""
self.address_length = ord(self.read_buf[0:1])
self.set_state(
"proxy_addr_2_2", length=1, expectBytes=self.address_length)
return True
def state_proxy_addr_2_2(self):
"""
Handle other addresses than IPv4 returned for peer
(e.g. IPv6, onion, ...). This is part 2 which retrieves the data.
"""
self.boundaddr = self.read_buf[0:self.address_length]
self.set_state("proxy_port", length=self.address_length, expectBytes=2)
return True
def state_proxy_port(self):
"""Handle peer's port being returned."""
self.boundport = struct.unpack(">H", self.read_buf[0:2])[0]
self.__proxysockname = (self.boundaddr, self.boundport)
if self.ipaddr is not None:
self.__proxypeername = (
socket.inet_ntoa(self.ipaddr), self.destination[1])
else:
self.__proxypeername = (self.destination[0], self.destport)
self.set_state("proxy_handshake_done", length=2)
return True
def proxy_sock_name(self):
"""Handle return value when using SOCKS5 for DNS resolving instead of connecting."""
return socket.inet_ntoa(self.__proxysockname[0])
class Socks5Connection(Socks5):
"""Child socks5 class used for making outbound connections."""
def __init__(self, address):
Socks5.__init__(self, address=address)
def state_auth_done(self):
"""Request connection to be made"""
# Now we can request the actual connection
self.append_write_buf(struct.pack('BBB', 0x05, 0x01, 0x00))
# If the given destination address is an IP address, we'll
# use the IPv4 address request even if remote resolving was specified.
try:
self.ipaddr = socket.inet_aton(self.destination[0])
self.append_write_buf(chr(0x01).encode() + self.ipaddr)
except socket.error:
# Well it's not an IP number, so it's probably a DNS name.
if Proxy._remote_dns: # pylint: disable=protected-access
# Resolve remotely
self.ipaddr = None
self.append_write_buf(chr(0x03).encode() + chr(
len(self.destination[0])).encode() + self.destination[0])
else:
# Resolve locally
self.ipaddr = socket.inet_aton(
socket.gethostbyname(self.destination[0]))
self.append_write_buf(chr(0x01).encode() + self.ipaddr)
self.append_write_buf(struct.pack(">H", self.destination[1]))
self.set_state("pre_connect", length=0, expectBytes=4)
return True
def state_pre_connect(self):
"""Tell socks5 to initiate a connection"""
try:
return Socks5.state_pre_connect(self)
except Socks5Error as e:
self.close_reason = e.message
self.set_state("close")
class Socks5Resolver(Socks5):
"""DNS resolver class using socks5"""
def __init__(self, host):
self.host = host
self.port = 8444
Socks5.__init__(self, address=(self.host, self.port))
def state_auth_done(self):
"""Perform resolving"""
# Now we can request the actual connection
self.append_write_buf(struct.pack('BBB', 0x05, 0xF0, 0x00))
self.append_write_buf(chr(0x03).encode() + chr(
len(self.host)).encode() + str(self.host))
self.append_write_buf(struct.pack(">H", self.port))
self.set_state("pre_connect", length=0, expectBytes=4)
return True
def resolved(self):
"""
Resolving is done, process the return value.
To use this within PyBitmessage, a callback needs to be
implemented which hasn't been done yet.
"""
print "Resolved %s as %s" % (self.host, self.proxy_sock_name())