# -*- coding:utf-8 -*-

import os

class SshProxyServer():

'''

A simple ssh proxy server.

'''

def __init__(self, **kwargs):

self.local_addr = kwargs['local_addr']

self.local_port = kwargs['local_port']

self.remote_host = kwargs['host']

self.remote_port = kwargs['remote_port']

self.remote_user = kwargs['user']

self.childpid = 0

def getArgs(self):

'''

return the ssh cmd arguments as a string.

'''

return ('ssh', '-TfN', '-D %d' % self.local_port,

'-p %d' % self.remote_port,

'%s@%s' % (self.remote_user, self.remote_host))

def daemond(self):

'''

make current process to become daemond.

'''

pid = os.fork()

if pid == -1 or pid > 0:

exit(0)

else:

os.setsid()

def spawnChild(self):

'''

create a new child process when child process exit.

'''

npid = os.fork()

if npid == -1:

exit(0)

elif npid == 0:

#new child process

self.start()

else:

#parent process

self.childpid = npid

def start(self):

'''

run the real command in the child process.

'''

os.execvp('ssh', self.getArgs())

def run(self):

'''

start running ssh proxy server.

'''

self.daemond()

self.spawnChild()

while True:

wpid, status = os.waitpid(self.childpid, 0)

if wpid == self.childpid and os.WIFEXITED(status):

# child process exit

self.spawnChild()

def main():

settings = {

'local_addr': '',

'local_port': 8888,

'remote_port': 22122,

'user': 'justdoit',

'host': 'shareyou.net.cn'

}

s = SshProxyServer(**settings)

s.run()

if __name__ == '__main__':

main()