gistfile1.txt

import os
import sys
import subprocess
import time
import datetime

# CONFIG #####################

# Network-Manager Name of VPN-Profile
# see <nmcli con>
# http://askubuntu.com/questions/57339/connect-disconnect-from-vpn-from-the-command-line
# http://forums.fedoraforum.org/showthread.php?t=276493
NM_VPN_ID = 'IPredator'

# how often the vpn-tunnel shall be tried to reconnect and the growing delay between retries
VPN_RECONNECT_MAX_RETRIES=10
VPN_RECONNECT_BASE_DELAY=30

# bitching NetworkManagerCLI: ** (process:2874): WARNING **: Could not deactivate connection '/org/freedesktop/NetworkManager/ActiveConnection/1': Not authorized to deactivate connections
# visudo -f /etc/sudoers.d/network-manager
# kai ALL=NOPASSWD: /usr/bin/nmcli

# Name of Torrent-Process
# see <ps axu>
TORRENT_PROC_PATH = '/usr/bin/transmission-gtk'
TORRENT_PROC_NAME='transmission-gtk'
# shorter/more fuzzy name to check if process is running using <pgrep>
TORRENT_PROC_CHECK='transmission'

# ping to see whether Internet over VPN-tunnel is alive or stalled
# https://developers.google.com/speed/public-dns/
CHECK_HOST_ALIVE = '8.8.8.8'

OUTPUT_FILE="check-vpn.log"
logFile = open(OUTPUT_FILE, "a")


# APP ########################

def main():
  if isAlive():
		log("internet-connection is alive, quitting.")
		sys.exit(0)
	else:
		isTun = isTunneled()
		isTor = isTorrenting()
		
		if not isTun:
			log("Internet-connection is stalled but there is no active VPN-tunnel present, quitting.")
		elif not isTor:
			log("Internet-connection is stalled but there is no active Torrent running, quitting.")
		else:
			stopTorrent()
			stopTunnel()
			time.sleep(10)
			reconnectTunnel()

			if isTunneled():
				log("VPN-tunnel successfully reestablished")
				startTorrent()
				sys.exit(0)
			else:
				log("failed to reestablish VPN-tunnel")
				sys.exit(1)
		
		sys.exit(0)


# LIB ########################

def isAlive():
	#return False
	log("checking for stalled connection, sending pings ...")
	rc1 = exek("ping -q -c 1 %s > /dev/null" % CHECK_HOST_ALIVE)
	time.sleep(3)
	rc2 = exek("ping -q -c 1 %s > /dev/null" % CHECK_HOST_ALIVE)
	time.sleep(3)
	rc3 = exek("ping -q -c 1 %s > /dev/null" % CHECK_HOST_ALIVE)
	return (rc1 == 0 or rc2 == 0 or rc3 == 0)

def isTunneled():
	log("checking network-manager status")
	# full vpn-state just for the log
	exek("sudo nmcli con status id %s | grep -e VPN-STATE" % NM_VPN_ID)
	rc =  exek("sudo nmcli con status id %s | grep -e VPN-STATE:.*5 > /dev/null" % NM_VPN_ID)
	return (rc == 0)

def isTorrenting():
	rc =  exek("pgrep -l %s" % TORRENT_PROC_CHECK)
	return (rc == 0)

def stopTunnel():
	log("sending network-manager tunnel down")
	rc = exek("sudo nmcli con down id %s" % NM_VPN_ID)
	return (rc == 0)

def startTunnel():
	log("sending network-manager tunnel up")
	rc = exek("sudo nmcli con up id %s" % NM_VPN_ID)
	return (rc == 0)

def reconnectTunnel(retries = 1):
	startTunnel()
	time.sleep(10)
	
	if not isTunneled():
		if retries <= VPN_RECONNECT_MAX_RETRIES:
			wait = VPN_RECONNECT_BASE_DELAY * retries
			log("could not reestablish VPN-tunnel, trying again in %d secs" % wait)
			time.sleep( wait )
			return reconnectTunnel(retries + 1)
		else:
			log("could not reestablish VPN-tunnel , aborting after %d retries." % retries)
			return False
	else:
		return True

def stopTorrent():
	log("sending QUIT to torrent-process")
	rc = exek("killall --signal QUIT %s" % TORRENT_PROC_NAME)
	log("RC:%s" % rc)

	time.sleep(10)

	log("sending safety-KILL to torrent-process")
	rc = exek("killall --signal KILL %s" % TORRENT_PROC_NAME)
	log("RC:%s" % rc)

def startTorrent():
	log("starting torrent-process ...")
	pid = subprocess.Popen([TORRENT_PROC_PATH], shell=False, stdin=None, stdout=None, stderr=None).pid
	log("successfully started with PID %s" % pid)
	return True

def log(s):
	print s
	logFile.write( s + "\n" )
	logFile.flush()

# http://docs.python.org/2/library/subprocess.html
def exek(cmd):
	rc =  subprocess.call(cmd, stdout=logFile, stderr=subprocess.STDOUT, shell=True)
	return rc

log("=== START ===")
main()