"""This module contains the implementation of the TCP forwarding, which allows
clients and servers to forward arbitrary TCP data across the connection.
This module is unstable.
Maintainer: U{Paul Swartz<mailto:z3p@twistedmatrix.com>}
"""
import struct
from twisted.internet import protocol, reactor
from twisted.python import log
import common, channel
class SSHListenForwardingFactory(protocol.Factory):
def __init__(self, connection, hostport, klass):
self.conn = connection
self.hostport = hostport self.klass = klass
def buildProtocol(self, addr):
channel = self.klass(conn = self.conn)
client = SSHForwardingClient(channel)
channel.client = client
addrTuple = (addr.host, addr.port)
channelOpenData = packOpen_direct_tcpip(self.hostport, addrTuple)
self.conn.openChannel(channel, channelOpenData)
return client
class SSHListenForwardingChannel(channel.SSHChannel):
def channelOpen(self, specificData):
log.msg('opened forwarding channel %s' % self.id)
if len(self.client.buf)>1:
b = self.client.buf[1:]
self.write(b)
self.client.buf = ''
def openFailed(self, reason):
self.closed()
def dataReceived(self, data):
self.client.transport.write(data)
def eofReceived(self):
self.client.transport.loseConnection()
def closed(self):
if hasattr(self, 'client'):
log.msg('closing local forwarding channel %s' % self.id)
self.client.transport.loseConnection()
del self.client
class SSHListenClientForwardingChannel(SSHListenForwardingChannel):
name = 'direct-tcpip'
class SSHListenServerForwardingChannel(SSHListenForwardingChannel):
name = 'forwarded-tcpip'
class SSHConnectForwardingChannel(channel.SSHChannel):
def __init__(self, hostport, *args, **kw):
channel.SSHChannel.__init__(self, *args, **kw)
self.hostport = hostport
self.client = None
self.clientBuf = ''
def channelOpen(self, specificData):
cc = protocol.ClientCreator(reactor, SSHForwardingClient, self)
log.msg("connecting to %s:%i" % self.hostport)
cc.connectTCP(*self.hostport).addCallbacks(self._setClient, self._close)
def _setClient(self, client):
self.client = client
log.msg("connected to %s:%i" % self.hostport)
if self.clientBuf:
self.client.transport.write(self.clientBuf)
self.clientBuf = None
if self.client.buf[1:]:
self.write(self.client.buf[1:])
self.client.buf = ''
def _close(self, reason):
log.msg("failed to connect: %s" % reason)
self.loseConnection()
def dataReceived(self, data):
if self.client:
self.client.transport.write(data)
else:
self.clientBuf += data
def closed(self):
if self.client:
log.msg('closed remote forwarding channel %s' % self.id)
if self.client.channel:
self.loseConnection()
self.client.transport.loseConnection()
del self.client
def openConnectForwardingClient(remoteWindow, remoteMaxPacket, data, avatar):
remoteHP, origHP = unpackOpen_direct_tcpip(data)
return SSHConnectForwardingChannel(remoteHP,
remoteWindow=remoteWindow,
remoteMaxPacket=remoteMaxPacket,
avatar=avatar)
class SSHForwardingClient(protocol.Protocol):
def __init__(self, channel):
self.channel = channel
self.buf = '\000'
def dataReceived(self, data):
if self.buf:
self.buf += data
else:
self.channel.write(data)
def connectionLost(self, reason):
if self.channel:
self.channel.loseConnection()
self.channel = None
def packOpen_direct_tcpip((connHost, connPort), (origHost, origPort)):
"""Pack the data suitable for sending in a CHANNEL_OPEN packet.
"""
conn = common.NS(connHost) + struct.pack('>L', connPort)
orig = common.NS(origHost) + struct.pack('>L', origPort)
return conn + orig
packOpen_forwarded_tcpip = packOpen_direct_tcpip
def unpackOpen_direct_tcpip(data):
"""Unpack the data to a usable format.
"""
connHost, rest = common.getNS(data)
connPort = int(struct.unpack('>L', rest[:4])[0])
origHost, rest = common.getNS(rest[4:])
origPort = int(struct.unpack('>L', rest[:4])[0])
return (connHost, connPort), (origHost, origPort)
unpackOpen_forwarded_tcpip = unpackOpen_direct_tcpip
def packGlobal_tcpip_forward((host, port)):
return common.NS(host) + struct.pack('>L', port)
def unpackGlobal_tcpip_forward(data):
host, rest = common.getNS(data)
port = int(struct.unpack('>L', rest[:4])[0])
return host, port
"""This is how the data -> eof -> close stuff /should/ work.
debug3: channel 1: waiting for connection
debug1: channel 1: connected
debug1: channel 1: read<=0 rfd 7 len 0
debug1: channel 1: read failed
debug1: channel 1: close_read
debug1: channel 1: input open -> drain
debug1: channel 1: ibuf empty
debug1: channel 1: send eof
debug1: channel 1: input drain -> closed
debug1: channel 1: rcvd eof
debug1: channel 1: output open -> drain
debug1: channel 1: obuf empty
debug1: channel 1: close_write
debug1: channel 1: output drain -> closed
debug1: channel 1: rcvd close
debug3: channel 1: will not send data after close
debug1: channel 1: send close
debug1: channel 1: is dead
"""