tcp2udp.py

from __future__ import print_function

import eventlet

eventlet.monkey_patch()

import argparse

from nclib import TCPServer, Netcat, NetcatError, NetcatTimeout


def binds_arg(arg):
    """
    :param str arg:
    :return:
    """
    parts = arg.split(':')
    lparts = len(parts)
    if lparts < 2 or lparts > 4:
        raise argparse.ArgumentError(arg, 'Invalid ports argument')
    dest_port = int(parts[-1])

    if lparts in [2, 3]:
        src_ip = '0.0.0.0'
        src_port = int(parts[0])
    else:  # lparts == 4
        src_ip = parts[0]
        src_port = int(parts[1])

    if lparts > 2:
        dest_ip = parts[-2]
    else:  # lparts == 2
        dest_ip = '127.0.0.1'

    return (src_ip, src_port), (dest_ip, dest_port)


def nc2nc(client1, client2):
    """
    :param Netcat client1:
    :param Netcat client2:
    """
    while True:
        try:
            client1.send(client2.recv())
        except (NetcatError, NetcatTimeout) as e:
            print(str(e) + ' %s:%d' % client1.peer)
            client1.close()
            client2.close()
            return


def main():
    parser = argparse.ArgumentParser(description="Multi-client forwarding of TCP connections to a UDP port")
    parser.add_argument(
        'binds',
        type=binds_arg,
        help='from:to => TCP-PORT:UDP-PORT or [IP:]TCP-PORT:IP:UDP-PORT; default IPs: src 0.0.0.0, dest 127.0.0.1'
    )
    args = parser.parse_args()
    src, dest = args.binds
    print('%s => %s' % (src, dest))

    pool = eventlet.GreenPool()
    tcp_server = TCPServer(src)

    try:
        for tcp_client in tcp_server:
            print('Accepted client %s:%d' % tcp_client.peer)
            udp_client = Netcat(dest, udp=True)
            pool.spawn_n(nc2nc, tcp_client, udp_client)
            pool.spawn_n(nc2nc, udp_client, tcp_client)
    except KeyboardInterrupt:
        tcp_server.close()
        exit(0)


if __name__ == '__main__':
    main()