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import os
import subprocess
from twisted.internet.task import LoopingCall
from twisted.internet import reactor
from twisted.logger import Logger
from .process import VPNProcess
from .constants import IS_MAC
log = Logger()
# NOTE: We need to set a bigger poll time in OSX because it seems
# openvpn malfunctions when you ask it a lot of things in a short
# amount of time. Check this!
POLL_TIME = 2.5 if IS_MAC else 1.0
class VPNControl(object):
"""
This is the high-level object that the service knows about.
It exposes the start and terminate methods.
On start, it spawns a VPNProcess instance that will use a vpnlauncher
suited for the running platform and connect to the management interface
opened by the openvpn process, executing commands over that interface on
demand.
"""
TERMINATE_MAXTRIES = 10
TERMINATE_WAIT = 1 # secs
RESTART_WAIT = 2 # secs
OPENVPN_VERB = "openvpn_verb"
def __init__(self, remotes, vpnconfig,
providerconfig, socket_host, socket_port):
self._vpnproc = None
self._pollers = []
self._openvpn_verb = None
self._user_stopped = False
self._remotes = remotes
self._vpnconfig = vpnconfig
self._providerconfig = providerconfig
self._host = socket_host
self._port = socket_port
def start(self):
log.debug('VPN: start')
self._user_stopped = False
self._stop_pollers()
args = [self._vpnconfig, self._providerconfig, self._host,
self._port]
kwargs = {'openvpn_verb': 7, 'remotes': self._remotes,
'restartfun': self.restart}
vpnproc = VPNProcess(*args, **kwargs)
if vpnproc.get_openvpn_process():
log.info('Another vpn process is running. Will try to stop it.')
vpnproc.stop_if_already_running()
try:
cmd = vpnproc.getCommand()
except Exception as e:
log.error('Error while getting vpn command... {0!r}'.format(e))
raise
env = os.environ
reactor.spawnProcess(vpnproc, cmd[0], cmd, env)
self._vpnproc = vpnproc
# add pollers for status and state
# this could be extended to a collection of
# generic watchers
poll_list = [LoopingCall(vpnproc.pollStatus),
LoopingCall(vpnproc.pollState)]
self._pollers.extend(poll_list)
self._start_pollers()
return True
def restart(self):
self.stop(shutdown=False, restart=True)
reactor.callLater(
self.RESTART_WAIT, self.start)
def stop(self, shutdown=False, restart=False):
"""
Stops the openvpn subprocess.
Attempts to send a SIGTERM first, and after a timeout
it sends a SIGKILL.
:param shutdown: whether this is the final shutdown
:type shutdown: bool
:param restart: whether this stop is part of a hard restart.
:type restart: bool
"""
self._stop_pollers()
# First we try to be polite and send a SIGTERM...
if self._vpnproc is not None:
# We assume that the only valid stops are initiated
# by an user action, not hard restarts
self._user_stopped = not restart
self._vpnproc.restarting = restart
self._sentterm = True
self._vpnproc.terminate_openvpn(shutdown=shutdown)
# ...but we also trigger a countdown to be unpolite
# if strictly needed.
reactor.callLater(
self.TERMINATE_WAIT, self._kill_if_left_alive)
else:
log.debug('VPN is not running.')
return True
@property
def status(self):
if not self._vpnproc:
return {'status': 'off', 'error': None}
return self._vpnproc.status
@property
def traffic_status(self):
return self._vpnproc.traffic_status
def _killit(self):
"""
Sends a kill signal to the process.
"""
self._stop_pollers()
if self._vpnproc is None:
log.debug("There's no vpn process running to kill.")
else:
self._vpnproc.aborted = True
self._vpnproc.killProcess()
def _kill_if_left_alive(self, tries=0):
"""
Check if the process is still alive, and send a
SIGKILL after a timeout period.
:param tries: counter of tries, used in recursion
:type tries: int
"""
while tries < self.TERMINATE_MAXTRIES:
if self._vpnproc.transport.pid is None:
return
else:
log.debug('Process did not die, waiting...')
tries += 1
reactor.callLater(self.TERMINATE_WAIT,
self._kill_if_left_alive, tries)
return
# after running out of patience, we try a killProcess
log.debug('Process did not die. Sending a SIGKILL.')
try:
self._killit()
except OSError:
log.error('Could not kill process!')
def _start_pollers(self):
"""
Iterate through the registered observers
and start the looping call for them.
"""
for poller in self._pollers:
poller.start(POLL_TIME)
def _stop_pollers(self):
"""
Iterate through the registered observers
and stop the looping calls if they are running.
"""
for poller in self._pollers:
if poller.running:
poller.stop()
self._pollers = []
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