A TCP hole puncher

tcphole.py

#!/usr/bin/python3
# tcphole.py
# By George Hilliard ("thirtythreeforty")

# A simple TCP hole puncher for a firewall accepting only ESTABLISHED,RELATED packets
# This currently binds to the localhost address, although that's easy to fix by changing
# the bind() calls.
# This is based on the theory found at http://www.bford.info/pub/net/p2pnat/index.html#sec-tcp.

# You may use this software under the terms of the Creative Commons CC-0 license.
# That is, it is public domain.  However, I'd appreciate it if you'd mention my name.

import sys
import socket
import _thread as thread

def client():
    c = socket.socket()

    c.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    c.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT, 1)

    c.bind(('', int(sys.argv[3])))
    while(c.connect_ex((sys.argv[1], int(sys.argv[2])))):
        pass
    print("client connected!")
    while True:
        pass

def server():
    c = socket.socket()

    c.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    c.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT, 1)

    c.bind(('', int(sys.argv[3])))
    c.listen(5)
    c.accept()
    print("server connected!")
    while True:
        pass

def main():
    thread.start_new_thread(client, ())
    thread.start_new_thread(server, ())

    while True:
        pass

if __name__ == '__main__':
    main()