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