#!/usr/bin/env python # Copyright (C) 2003-2007 Robey Pointer # # This file is part of paramiko. # # Paramiko is free software; you can redistribute it and/or modify it under the # terms of the GNU Lesser General Public License as published by the Free # Software Foundation; either version 2.1 of the License, or (at your option) # any later version. # # Paramiko is distrubuted in the hope that it will be useful, but WITHOUT ANY # WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR # A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more # details. # # You should have received a copy of the GNU Lesser General Public License # along with Paramiko; if not, write to the Free Software Foundation, Inc., # 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. """ Sample script showing how to do local port forwarding over paramiko. This script connects to the requested SSH server and sets up local port forwarding (the openssh -L option) from a local port through a tunneled connection to a destination reachable from the SSH server machine. """ from __future__ import print_function import getpass import os import socket import select import SocketServer import sys from optparse import OptionParser import paramiko SSH_PORT = 22 DEFAULT_PORT = 4000 g_verbose = True class ForwardServer (SocketServer.ThreadingTCPServer): daemon_threads = True allow_reuse_address = True class Handler (SocketServer.BaseRequestHandler): def handle(self): try: chan = self.ssh_transport.open_channel('direct-tcpip', (self.chain_host, self.chain_port), self.request.getpeername()) except Exception as e: verbose('Incoming request to %s:%d failed: %s' % (self.chain_host, self.chain_port, repr(e))) return if chan is None: verbose('Incoming request to %s:%d was rejected by the SSH server.' % (self.chain_host, self.chain_port)) return verbose('Connected! Tunnel open %r -> %r -> %r' % (self.request.getpeername(), chan.getpeername(), (self.chain_host, self.chain_port))) while True: r, w, x = select.select([self.request, chan], [], []) if self.request in r: data = self.request.recv(1024) if len(data) == 0: break chan.send(data) if chan in r: data = chan.recv(1024) if len(data) == 0: break self.request.send(data) chan.close() self.request.close() verbose('Tunnel closed from %r' % (self.request.getpeername(),)) def forward_tunnel(local_port, remote_host, remote_port, transport): # this is a little convoluted, but lets me configure things for the Handler # object. (SocketServer doesn't give Handlers any way to access the outer # server normally.) class SubHander (Handler): chain_host = remote_host chain_port = remote_port ssh_transport = transport ForwardServer(('', local_port), SubHander).serve_forever() def verbose(s): if g_verbose: print(s) HELP = """\ Set up a forward tunnel across an SSH server, using paramiko. A local port (given with -p) is forwarded across an SSH session to an address:port from the SSH server. This is similar to the openssh -L option. """ def get_host_port(spec, default_port): "parse 'hostname:22' into a host and port, with the port optional" args = (spec.split(':', 1) + [default_port])[:2] args[1] = int(args[1]) return args[0], args[1] def parse_options(): global g_verbose parser = OptionParser(usage='usage: %prog [options] [:]', version='%prog 1.0', description=HELP) parser.add_option('-q', '--quiet', action='store_false', dest='verbose', default=True, help='squelch all informational output') parser.add_option('-p', '--local-port', action='store', type='int', dest='port', default=DEFAULT_PORT, help='local port to forward (default: %d)' % DEFAULT_PORT) parser.add_option('-u', '--user', action='store', type='string', dest='user', default=getpass.getuser(), help='username for SSH authentication (default: %s)' % getpass.getuser()) parser.add_option('-K', '--key', action='store', type='string', dest='keyfile', default=None, help='private key file to use for SSH authentication') parser.add_option('', '--no-key', action='store_false', dest='look_for_keys', default=True, help='don\'t look for or use a private key file') parser.add_option('-P', '--password', action='store_true', dest='readpass', default=False, help='read password (for key or password auth) from stdin') parser.add_option('-r', '--remote', action='store', type='string', dest='remote', default=None, metavar='host:port', help='remote host and port to forward to') options, args = parser.parse_args() if len(args) != 1: parser.error('Incorrect number of arguments.') if options.remote is None: parser.error('Remote address required (-r).') g_verbose = options.verbose server_host, server_port = get_host_port(args[0], SSH_PORT) remote_host, remote_port = get_host_port(options.remote, SSH_PORT) return options, (server_host, server_port), (remote_host, remote_port) def main(): options, server, remote = parse_options() password = None if options.readpass: password = getpass.getpass('Enter SSH password: ') client = paramiko.SSHClient() client.load_system_host_keys() client.set_missing_host_key_policy(paramiko.WarningPolicy()) verbose('Connecting to ssh host %s:%d ...' % (server[0], server[1])) try: client.connect(server[0], server[1], username=options.user, key_filename=options.keyfile, look_for_keys=options.look_for_keys, password=password) except Exception as e: print('*** Failed to connect to %s:%d: %r' % (server[0], server[1], e)) sys.exit(1) verbose('Now forwarding port %d to %s:%d ...' % (options.port, remote[0], remote[1])) try: forward_tunnel(options.port, remote[0], remote[1], client.get_transport()) except KeyboardInterrupt: print('C-c: Port forwarding stopped.') sys.exit(0) if __name__ == '__main__': main()