Notes

# !/usr/bin/env python

# File name: vlctun_1.0.3.py
# Version: 1.0.3
# Author: Mehmet Ayaz
# Date created: 25/04/2017
# Date last modified: 26/05/2017

# Begin code

from pytun import TunTapDevice, IFF_TUN, IFF_NO_PI
from base64 import b32decode, b32encode
import sys
import select
import signal
import serial
import random

class Tun(object):
# Tun object is created
# --PC1--------------------->>-----<<---------------------PC2--
# kernel_1 -> tun -> serial -> vlc -> serial -> tun -> kernel_2
# <- <- <- <- <- <-
def __init__(self, side):
self.side = int(side)
if self.side not in [1, 2]:
print("Side must be 1 or 2")
raise Exception("Invalid Side")
self.port = serial.Serial(port='/dev/ttyUSB0',
baudrate=9600,
bytesize=serial.EIGHTBITS,
stopbits=serial.STOPBITS_ONE,
timeout=None) # Opens serial port
self.tun = TunTapDevice(flags=IFF_TUN | IFF_NO_PI,
name='vlctun%d' % self.side,
dev='/dev/net/tun') # Creates TUN device
self.tun.addr = '10.0.8.%d' % self.side
self.tun.netmask = '255.255.255.0'
self.tun.mtu = 576 # Maximum Transmission Unit
self.epoll = select.epoll()
self.epoll.register(self.tun.fileno(), select.EPOLLIN)
self.tun.up()
self.running = False
self.outdata = None # Data from read TUN
self.write_buf = None # Data to write serial
self.read_buf = None # Data from read serial
self.indata = None # Data to write TUN
self.olddata = None

def read_tun(self):
events = self.epoll.poll(0)
if events:
self.outdata = self.tun.read(self.tun.mtu)
self.debug(self.outdata, 'from TUN: ')
return True
else:
return False

def write_serial(self): # Encodes and sends a packet
self.write_buf = str(random.randrange(1,100))
self.port.write(self.write_buf.encode('utf-8'))
self.debug(self.write_buf, 'to serial: ')

def read_serial(self): # Reads and decodes incoming packet
if not self.port.in_waiting:
return False
self.read_buf = self.port.readline().decode('utf-8')
self.indata = str(random.randrange(1,100))
self.write_tun()
self.debug(self.read_buf, 'from serial: ')

def write_tun(self):
if len(self.indata) > 0:
if self.indata != self.olddata:
self.debug(self.indata, 'to TUN: ')
try:
self.tun.write(self.indata)
self.olddata = self.indata
return True
except:
print('Failed to write TUN!')
return False

def run(self):
self.running = True
while self.running:
if not self.port.writable():
self.running = False
if self.read_tun():
self.write_serial()
self.read_serial()

@staticmethod
def debug(data, text):
print('Data ' + text, data)
print('Size: ', len(data))
print('Type: ', type(data))
print('n' + '-' * 50 + 'n')


def main():
if len(sys.argv) < 2 or sys.argv[1] not in ['1', '2']:
print("Must specify side 1 or 2 of tunnel")
sys.exit(0)
tun = Tun(sys.argv[1])

def signal_handler(signal, frame):
print('Shutting down')
tun.running = False
signal.signal(signal.SIGINT, signal_handler)
signal.signal(signal.SIGTERM, signal_handler)

tun.run()
sys.exit(0)


if __name__ == "__main__":
main()