from signal import SIGTERM, signal
from subprocess import CalledProcessError, check_output
from sys import exit
from time import sleep

PING_INTERVAL_IN_SECONDS = 80

signal(SIGTERM, lambda signum, frame: exit(0))


def getDefaultRoute():
    routes = check_output(['route', '-n']).decode('utf-8').splitlines()
    defaults = [r.split()[1] for r in routes if r.startswith('0.0.0.0')]

    return defaults[0] if defaults else None


def keepalive(defaultRoute):
    while True:
        sleep(PING_INTERVAL_IN_SECONDS)
        ping(defaultRoute)


def ping(address):
    try:
        check_output(['ping', '-c', '1', address])
    except CalledProcessError as e:
        pass


defaultRoute = getDefaultRoute()
keepalive(defaultRoute) if defaultRoute else print('No default route')