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'''
Created on Jan 14, 2013
@author: steger
'''
import select
import SocketServer
import sys
import paramiko
#FIXME: let an SshTunnel instance launch a new thread;
#TODO: docs
#TODO: localport could be retrieved from a pool
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, e:
print('Incoming request to %s:%d failed: %s' % (self.chain_host,
self.chain_port,
repr(e)))
return
if chan is None:
print('Incoming request to %s:%d was rejected by the SSH server.' %
(self.chain_host, self.chain_port))
return
print('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()
print ('Tunnel closed from %r' % (self.request.getpeername(),))
class SshTunnel(object):
'''
This class establishes a connection 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.
'''
def __init__(self):
pass
def setup(self, localport = 4000, username = 'root', server = 'localhost', serverport = 22, remoteserver = 'localhost', remoteport = 22, keyfile = None, password = None,
look_for_keys = False):
'''
Constructor
'''
client = paramiko.SSHClient()
client.load_system_host_keys()
client.set_missing_host_key_policy(paramiko.WarningPolicy())
print ('Connecting to ssh host %s:%d ...' % (server, serverport))
try:
client.connect(server, serverport, username = username, key_filename = keyfile,
look_for_keys = look_for_keys, password = password)
except Exception, e:
print '*** Failed to connect to %s:%d: %r' % (server, serverport, e)
sys.exit(1)
print ('Now forwarding port %d to %s:%d ...' % (localport, remoteserver, remoteport))
try:
# 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 = remoteserver
chain_port = remoteport
ssh_transport = client.get_transport()
self.service = ForwardServer(('', localport), SubHander)
self.service.serve_forever()
except KeyboardInterrupt:
print 'C-c: Port forwarding stopped.'
sys.exit(0)
def teardown(self):
print "ENDE"
self.service.shutdown()
if __name__ == '__main__':
T = SshTunnel()
from threading import Timer
t = Timer(5.0, T.teardown)
t.start() # after 30 seconds, "hello, world" will be printed
T.setup(username = 'novi_novi', server = 'novilab.elte.hu', remoteserver = 'complex.elte.hu', keyfile = '/home/steger/Private/ssh/novi_rsa')
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