[project @ robey@lag.net-20080220060035-yi82h5kc7jod5hlu]

add a demo for reverse port forwarding.

demos/rforward.py

@@ -0,0 +1,167 @@
+#!/usr/bin/env python
+
+# Copyright (C) 2008  Robey Pointer <robey@lag.net>
+#
+# 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 remote port forwarding over paramiko.
+
+This script connects to the requested SSH server and sets up remote port
+forwarding (the openssh -R option) from a remote port through a tunneled
+connection to a destination reachable from the local machine.
+"""
+
+import getpass
+import os
+import socket
+import select
+import sys
+import threading
+from optparse import OptionParser
+
+import paramiko
+
+SSH_PORT = 22
+DEFAULT_PORT = 4000
+
+g_verbose = True
+
+
+def handler(chan, host, port):
+    sock = socket.socket()
+    try:
+        sock.connect((host, port))
+    except Exception, e:
+        verbose('Forwarding request to %s:%d failed: %r' % (host, port, e))
+        return
+    
+    verbose('Connected!  Tunnel open %r -> %r -> %r' % (chan.origin_addr,
+                                                        chan.getpeername(), (host, port)))
+    while True:
+        r, w, x = select.select([sock, chan], [], [])
+        if sock in r:
+            data = sock.recv(1024)
+            if len(data) == 0:
+                break
+            chan.send(data)
+        if chan in r:
+            data = chan.recv(1024)
+            if len(data) == 0:
+                break
+            sock.send(data)
+    chan.close()
+    sock.close()
+    verbose('Tunnel closed from %r' % (chan.origin_addr,))
+
+
+def reverse_forward_tunnel(server_port, remote_host, remote_port, transport):
+    transport.request_port_forward('', server_port)
+    while True:
+        chan = transport.accept(1000)
+        if chan is None:
+            continue
+        thr = threading.Thread(target=handler, args=(chan, remote_host, remote_port))
+        thr.setDaemon(True)
+        thr.start()
+
+
+def verbose(s):
+    if g_verbose:
+        print s
+
+
+HELP = """\
+Set up a reverse forwarding tunnel across an SSH server, using paramiko. A
+port on the SSH server (given with -p) is forwarded across an SSH session
+back to the local machine, and out to a remote site reachable from this
+network. This is similar to the openssh -R 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', '--remote-port', action='store', type='int', dest='port',
+                      default=DEFAULT_PORT,
+                      help='port on server 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, e:
+        print '*** Failed to connect to %s:%d: %r' % (server[0], server[1], e)
+        sys.exit(1)
+
+    verbose('Now forwarding remote port %d to %s:%d ...' % (options.port, remote[0], remote[1]))
+
+    try:
+        reverse_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()