autovpn.py

#!/usr/bin/python
from dbus.mainloop.glib import DBusGMainLoop
import dbus
import gobject
import sys
##
##
# This should keep alive a VPN connection.
##
##
class AutoVPN:

	def __init__(self, vpn_name, max_attempts, delay):
		self.vpn_name = vpn_name
		self.max_attempts = max_attempts
		self.delay = delay

		print "Maintaining connection for %s, reattempting up to %d times with %d ms between retries" % (vpn_name, max_attempts, delay)
		self.failed_attempts = 0
		self.bus = dbus.SystemBus()
		self.get_network_manager().connect_to_signal("StateChanged", self.onNetworkStateChanged)

	def onNetworkStateChanged(self, state):
		'Handles network status changes and activates the VPN on established connection.'
		print "Network state changed: %d" % state
		if state == 3:
			self.activate_vpn()

	def onVpnStateChanged(self, state, reason):
		'Handles vpn status changes and eventually reconnects the VPN.'
		# vpn connected or user disconnected manually?
		if state == 5 or (state == 7 and reason == 2):
			print "VPN connected, or user disconnected manually"
			self.failed_attempts = 0
			return
		# connection failed or unknown?
		elif state in [6, 7]:
			if self.failed_attempts < self.max_attempts:
				print "Connection failed, attempting to reconnect"
				self.failed_attempts += 1
				gobject.timeout_add(self.delay, self.activate_vpn)
			else:
				print "Connection failed, exceeded %d max attempts." % self.max_attempts
				self.failed_attempts = 0

	def get_network_manager(self):
		'Gets the network manager interface.'
		print "Getting NetworkManager DBUS interface"
		proxy = self.bus.get_object('org.freedesktop.NetworkManager', '/org/freedesktop/NetworkManager')
		return dbus.Interface(proxy, 'org.freedesktop.NetworkManager')

	def get_vpn_connection(self, name):
		'Gets the VPN connection interface with the specified name.'
		print "Getting %s VPN connection DBUS interface" % name
		proxy = self.bus.get_object('org.freedesktop.NetworkManagerUserSettings', '/org/freedesktop/NetworkManagerSettings')
		iface = dbus.Interface(proxy, 'org.freedesktop.NetworkManagerSettings')
		connections = iface.ListConnections()
		for connection in connections:
			proxy = self.bus.get_object('org.freedesktop.NetworkManagerUserSettings', connection)
			iface = dbus.Interface(proxy, 'org.freedesktop.NetworkManagerSettings.Connection')
			con_settings = iface.GetSettings()['connection']
			if con_settings['type'] == 'vpn' and con_settings['id'] == name:
				print "Got %s interface" % name
				return connection
		print "Unable to acquire %s VPN interface. Does it exist?" % name
		return None

	def get_active_connection(self):
		'Gets the interface of the active network connection.'
		print "Getting active network connection"
		proxy = self.bus.get_object('org.freedesktop.NetworkManager', '/org/freedesktop/NetworkManager')
		iface = dbus.Interface(proxy, 'org.freedesktop.DBus.Properties')
		active_connections = iface.Get('org.freedesktop.NetworkManager', 'ActiveConnections')
		if len(active_connections) == 0:
			print "No active connections found"
			return None
		print "Found %d active connection(s)" % active_connections.len
		return active_connections[0]

	def activate_vpn(self):
		'Activates the vpn connection.'
		print "Activating %s VPN connection" % self.vpn_name
		vpn_con = self.get_vpn_connection(self.vpn_name)
		active_con = self.get_active_connection()
		if vpn_con and active_con:
			new_con = self.get_network_manager().ActivateConnection('org.freedesktop.NetworkManagerUserSettings',
				vpn_con,
				dbus.ObjectPath("/"),
				active_con)
			proxy = self.bus.get_object('org.freedesktop.NetworkManager', new_con)
			iface = dbus.Interface(proxy, 'org.freedesktop.NetworkManager.VPN.Connection')
			iface.connect_to_signal('VpnStateChanged', self.onVpnStateChanged)
			print "Connection should be active"

if __name__ == '__main__':

	# check arguments
	if len(sys.argv) != 2:
		print 'usage: autovpn <VPN_CONNECTION_NAME>'
		sys.exit(0)

	# set up the main loop
	DBusGMainLoop(set_as_default = True)
	loop = gobject.MainLoop()

	max_attempts = 5
	delay = 5000
	# intialize the autovpn object
	AutoVPN(sys.argv[1], max_attempts, delay)
	
	# execute the main loop
	loop.run()