240 lines
7.6 KiB
Python
240 lines
7.6 KiB
Python
# -*- test-case-name: twisted.test.test_socks -*-
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# Copyright (c) Twisted Matrix Laboratories.
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# See LICENSE for details.
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"""
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Implementation of the SOCKSv4 protocol.
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"""
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# python imports
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import struct
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import string
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import socket
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import time
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# twisted imports
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from twisted.internet import reactor, protocol, defer
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from twisted.python import log
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class SOCKSv4Outgoing(protocol.Protocol):
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def __init__(self,socks):
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self.socks=socks
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def connectionMade(self):
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peer = self.transport.getPeer()
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self.socks.makeReply(90, 0, port=peer.port, ip=peer.host)
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self.socks.otherConn=self
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def connectionLost(self, reason):
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self.socks.transport.loseConnection()
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def dataReceived(self,data):
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self.socks.write(data)
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def write(self,data):
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self.socks.log(self,data)
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self.transport.write(data)
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class SOCKSv4Incoming(protocol.Protocol):
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def __init__(self,socks):
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self.socks=socks
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self.socks.otherConn=self
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def connectionLost(self, reason):
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self.socks.transport.loseConnection()
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def dataReceived(self,data):
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self.socks.write(data)
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def write(self,data):
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self.socks.log(self,data)
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self.transport.write(data)
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class SOCKSv4(protocol.Protocol):
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"""
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An implementation of the SOCKSv4 protocol.
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@type logging: C{str} or C{None}
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@ivar logging: If not C{None}, the name of the logfile to which connection
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information will be written.
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@type reactor: object providing L{twisted.internet.interfaces.IReactorTCP}
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@ivar reactor: The reactor used to create connections.
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@type buf: C{str}
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@ivar buf: Part of a SOCKSv4 connection request.
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@type otherConn: C{SOCKSv4Incoming}, C{SOCKSv4Outgoing} or C{None}
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@ivar otherConn: Until the connection has been established, C{otherConn} is
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C{None}. After that, it is the proxy-to-destination protocol instance
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along which the client's connection is being forwarded.
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"""
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def __init__(self, logging=None, reactor=reactor):
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self.logging = logging
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self.reactor = reactor
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def connectionMade(self):
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self.buf = ""
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self.otherConn = None
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def dataReceived(self, data):
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"""
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Called whenever data is received.
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@type data: C{str}
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@param data: Part or all of a SOCKSv4 packet.
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"""
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if self.otherConn:
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self.otherConn.write(data)
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return
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self.buf = self.buf + data
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completeBuffer = self.buf
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if "\000" in self.buf[8:]:
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head, self.buf = self.buf[:8], self.buf[8:]
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version, code, port = struct.unpack("!BBH", head[:4])
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user, self.buf = self.buf.split("\000", 1)
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if head[4:7] == "\000\000\000" and head[7] != "\000":
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# An IP address of the form 0.0.0.X, where X is non-zero,
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# signifies that this is a SOCKSv4a packet.
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# If the complete packet hasn't been received, restore the
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# buffer and wait for it.
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if "\000" not in self.buf:
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self.buf = completeBuffer
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return
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server, self.buf = self.buf.split("\000", 1)
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d = self.reactor.resolve(server)
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d.addCallback(self._dataReceived2, user,
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version, code, port)
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d.addErrback(lambda result, self = self: self.makeReply(91))
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return
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else:
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server = socket.inet_ntoa(head[4:8])
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self._dataReceived2(server, user, version, code, port)
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def _dataReceived2(self, server, user, version, code, port):
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"""
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The second half of the SOCKS connection setup. For a SOCKSv4 packet this
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is after the server address has been extracted from the header. For a
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SOCKSv4a packet this is after the host name has been resolved.
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@type server: C{str}
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@param server: The IP address of the destination, represented as a
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dotted quad.
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@type user: C{str}
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@param user: The username associated with the connection.
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@type version: C{int}
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@param version: The SOCKS protocol version number.
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@type code: C{int}
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@param code: The comand code. 1 means establish a TCP/IP stream
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connection, and 2 means establish a TCP/IP port binding.
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@type port: C{int}
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@param port: The port number associated with the connection.
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"""
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assert version == 4, "Bad version code: %s" % version
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if not self.authorize(code, server, port, user):
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self.makeReply(91)
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return
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if code == 1: # CONNECT
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d = self.connectClass(server, port, SOCKSv4Outgoing, self)
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d.addErrback(lambda result, self = self: self.makeReply(91))
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elif code == 2: # BIND
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d = self.listenClass(0, SOCKSv4IncomingFactory, self, server)
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d.addCallback(lambda (h, p),
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self = self: self.makeReply(90, 0, p, h))
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else:
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raise RuntimeError, "Bad Connect Code: %s" % code
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assert self.buf == "", "hmm, still stuff in buffer... %s" % repr(
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self.buf)
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def connectionLost(self, reason):
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if self.otherConn:
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self.otherConn.transport.loseConnection()
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def authorize(self,code,server,port,user):
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log.msg("code %s connection to %s:%s (user %s) authorized" % (code,server,port,user))
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return 1
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def connectClass(self, host, port, klass, *args):
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return protocol.ClientCreator(reactor, klass, *args).connectTCP(host,port)
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def listenClass(self, port, klass, *args):
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serv = reactor.listenTCP(port, klass(*args))
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return defer.succeed(serv.getHost()[1:])
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def makeReply(self,reply,version=0,port=0,ip="0.0.0.0"):
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self.transport.write(struct.pack("!BBH",version,reply,port)+socket.inet_aton(ip))
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if reply!=90: self.transport.loseConnection()
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def write(self,data):
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self.log(self,data)
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self.transport.write(data)
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def log(self,proto,data):
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if not self.logging: return
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peer = self.transport.getPeer()
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their_peer = self.otherConn.transport.getPeer()
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f=open(self.logging,"a")
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f.write("%s\t%s:%d %s %s:%d\n"%(time.ctime(),
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peer.host,peer.port,
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((proto==self and '<') or '>'),
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their_peer.host,their_peer.port))
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while data:
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p,data=data[:16],data[16:]
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f.write(string.join(map(lambda x:'%02X'%ord(x),p),' ')+' ')
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f.write((16-len(p))*3*' ')
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for c in p:
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if len(repr(c))>3: f.write('.')
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else: f.write(c)
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f.write('\n')
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f.write('\n')
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f.close()
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class SOCKSv4Factory(protocol.Factory):
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"""
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A factory for a SOCKSv4 proxy.
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Constructor accepts one argument, a log file name.
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"""
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def __init__(self, log):
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self.logging = log
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def buildProtocol(self, addr):
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return SOCKSv4(self.logging, reactor)
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class SOCKSv4IncomingFactory(protocol.Factory):
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"""
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A utility class for building protocols for incoming connections.
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"""
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def __init__(self, socks, ip):
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self.socks = socks
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self.ip = ip
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def buildProtocol(self, addr):
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if addr[0] == self.ip:
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self.ip = ""
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self.socks.makeReply(90, 0)
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return SOCKSv4Incoming(self.socks)
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elif self.ip == "":
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return None
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else:
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self.socks.makeReply(91, 0)
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self.ip = ""
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return None
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