port forward to access ncl experiments via rdp

ncl-port-forward.py

#!/usr/bin/python3

import subprocess
import socket
import argparse
import os

# You may change this to your own ncl account
ncl_username = "username"

def is_port_in_use(port):
    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
        return (s.connect_ex(('localhost', port)) == 0)

def main():
    parser = argparse.ArgumentParser(description='Set up port forwarding for NCL testbed.')
    parser.add_argument('--username', type=str, help='ssh username for your NCL testbed.', default=ncl_username)

    args = parser.parse_args()

    # Find a free local port 
    local_port = 10000
    while (is_port_in_use(local_port)):
        local_port += 1

    remote_port = 12344 

    # Print hint
    print("If this script freezes after you enter your password, then it is working! Keep it running here.")
    print("Use the this command to make a rdesktop connection in another terminal:")
    print("\trdesktop -a 16 localhost:" + str(local_port))

    # Make comand
    cmd = ["/usr/bin/ssh", 
           "-N", 
           "-L", 
           str(local_port)+":node.experiment.team.ncl.sg:"+str(remote_port),
           args.username+"@users.ncl.sg"]

    # Run~!
    while (True):
        try:
            print(subprocess.check_output(cmd))
        except (KeyboardInterrupt):
            # Capture ctrl+c
            exit()
        print("An error occurred. Try again?")
        

if __name__ == '__main__':
    main()