Arduino TCP/IP programming tunnel by SISTEMAS O.R.P.

#!/usr/bin/env python

# Copyright (C) 2014 SISTEMAS O.R.P.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

import select
import socket
import errno

port = 50000
client1 = None
client2 = None
loop = 1

print "Arduino TCP/IP programming tunnel"
server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server.bind(('',port))
server.listen(2)
inputs = [server]

print "Waiting for both connections..."

while loop:
    rlist, wlist, xlist = select.select(inputs,[],[])

    for s in rlist:

        if s == server:
            if client1 is None:
                client1, address1 = s.accept()
                inputs.append(client1)
                print address1[0], " (1) connected"
            elif client2 is None:
                client2, address2 = s.accept()
                inputs.append(client2)
                print address2[0], " (2) connected"
            else:
                client3, address3 = s.accept()
                client3.send("Get out of here!!!")
                client3.close()
                print "An unexpected connection from", address3[0], "has been closed."

        else:
            disconnection = 0
            try:
                data = s.recv(1024)
            except socket.error as error:
                if error.errno == errno.WSAECONNRESET:
                    disconnection = 1
                else:
                    raise

            if disconnection == 0 and data:
                if s == client1:
                    if client2 is not None:
                        client2.send(data)
                else:
                    if client1 is not None:
                        client1.send(data)
            else:
                if s == client1:
                    print address1[0]," (1) disconnected"
                    inputs.remove(client1)
                    if client2 is not None:
                        inputs.remove(client2)
                        client2.close()
                else:
                    print address2[0]," (2) disconnected"
                    inputs.remove(client2)
                    if client1 is not None:
                        inputs.remove(client1)
                        client1.close()


                client1 = None
                client2 = None
                loop = 0
server.close()
print "Programming tunnel finished"