#!/usr/bin/env python3
#
# Copyright (C) 2024 VyOS maintainers and contributors
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 or later as
# published by the Free Software Foundation.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

# This is a Python hook script which is invoked whenever a PPPoE session goes
# "ip-up". It will call into our vyos.ifconfig library and will then execute
# common tasks for the PPPoE interface. The reason we have to "hook" this is
# that we can not create a pppoeX interface in advance in linux and then connect
# pppd to this already existing interface.

import os
import signal

from sys import argv
from sys import exit

from vyos.defaults import directories

# When the ppp link comes up, this script is called with the following
# parameters
#       $1      the interface name used by pppd (e.g. ppp3)
#       $2      the tty device name
#       $3      the tty device speed
#       $4      the local IP address for the interface
#       $5      the remote IP address
#       $6      the parameter specified by the 'ipparam' option to pppd

if (len(argv) < 7):
    exit(1)

wlb_pid_file = '/run/wlb_daemon.pid'

interface = argv[6]
nexthop = argv[5]

if not os.path.exists(directories['ppp_nexthop_dir']):
    os.mkdir(directories['ppp_nexthop_dir'])

nexthop_file = os.path.join(directories['ppp_nexthop_dir'], interface)

with open(nexthop_file, 'w') as f:
    f.write(nexthop)

# Trigger WLB daemon update
if os.path.exists(wlb_pid_file):
    with open(wlb_pid_file, 'r') as f:
        pid = int(f.read())

        os.kill(pid, signal.SIGUSR2)