TCP reverse proxy with epoll (not working)

gistfile1.py

#!/usr/bin/env python
# TCP Proxy

# Each socket has a read buffers
# if we proxy s1 <-> s2 then
# s1 writes to s2 read buffer
# s2 writes to s1 read buffer

# Using epool (kqueue?)
# When new event on server socket:
#   - Accept
#   - Create new socket to backend
#   - Register read/write on both sockets

# Based on http://scotdoyle.com/python-epoll-howto.html

import select
import socket



def new_socket():
    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    sock.setblocking(0)
    sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)

    return sock


def match_maker(poll, conn, connections, buffers, mapping):
    conn.setblocking(0)

    backend = new_socket()
    backend.connect(('localhost', 8080))

    buffers[backend.fileno()] = ''
    connections[backend.fileno()] = backend
    poll.register(backend.fileno(),
                  select.EPOLLIN | select.EPOLLOUT)

    buffers[conn.fileno()] = ''
    connections[conn.fileno()] = conn
    poll.register(conn.fileno(), select.EPOLLIN | select.EPOLLOUT)


    mapping[conn.fileno()] = backend.fileno()
    mapping[backend.fileno()] = conn.fileno()


def main(argv=None):
    import sys
    from argparse import ArgumentParser

    argv = argv or sys.argv

    parser = ArgumentParser(description='')
    parser.add_argument('port', help='port to listen on', type=int)
    args = parser.parse_args(argv[1:])

    server = new_socket()
    server.bind(('localhost', args.port))
    server.listen(1)


    connections, buffers, mapping = {}, {}, {}
    poll = select.epoll()
    poll.register(server.fileno(), select.EPOLLIN)
    try:
        while True:
            for fileno, event in poll.poll(1):
                if fileno == server.fileno():
                    # New connection
                    conn, address = server.accept()
                    match_maker(poll, conn, connections, buffers, mapping)
                elif event & select.EPOLLIN:
                    other = mapping[fileno]
                    buffers[other] += connections[fileno].recv(1024)
                elif event & select.EPOLLOUT:
                    size = connections[fileno].send(buffers[fileno])
                    if size == 0:
                        connections[fileno].shutdown(socket.SHUT_RDWR)
                        poll.modify(fileno, 0)
                        other = connections[mapping[fileno]]
                        other.shutdown(socket.SHUT_RDWR)
                        poll.modify(other.fileno(), 0)
                elif event & select.EPOLLHUP:
                    poll.unregister(fileno)
                    connections.pop(fileno)
                    buffers.pop(fileno)

                    other = connections[mapping[fileno]]
                    other.shutdown(socket.SHUT_RDWR)
                    poll.modify(other.fileno(), 0)
    finally:
        poll.unregister(server.fileno())
        poll.close()
        server.close()


if __name__ == '__main__':
    main()