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Diffstat (limited to 'demos/forward.py')
| -rw-r--r-- | demos/forward.py | 257 |
1 files changed, 257 insertions, 0 deletions
diff --git a/demos/forward.py b/demos/forward.py new file mode 100644 index 0000000..869e390 --- /dev/null +++ b/demos/forward.py @@ -0,0 +1,257 @@ +#!/usr/bin/env python + +# Copyright (C) 2003-2007 Robey Pointer <robeypointer@gmail.com> +# +# 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 distributed 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., +# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 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. +""" + +import getpass +import os +import socket +import select + +try: + import SocketServer +except ImportError: + import socketserver as 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) + + peername = self.request.getpeername() + chan.close() + self.request.close() + verbose("Tunnel closed from %r" % (peername,)) + + +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] <ssh-server>[:<server-port>]", + 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() |