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#!/usr/bin/env python
# Copyright (C) 2008 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.,
# 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 as 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 as 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()
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