#!/usr/bin/env python3
#
# Copyright 2023-2025 VyOS maintainers and contributors <maintainers@vyos.io>
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library 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
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library.  If not, see <http://www.gnu.org/licenses/>.

import sys

from time import sleep

from vyos.config import Config
from vyos.ifconfig import Section
from vyos.utils.boot import boot_configuration_complete
from vyos.utils.process import cmd
from vyos.utils.process import is_systemd_service_active
from vyos.utils.commit import commit_in_progress
from vyos import airbag

airbag.enable()

if len(sys.argv) < 3:
    airbag.noteworthy('Must specify both interface and link status!')
    sys.exit(1)

if not boot_configuration_complete():
    airbag.noteworthy('System bootup not yet finished...')
    sys.exit(1)

interface = sys.argv[1]

while commit_in_progress():
    sleep(0.250)

in_out = sys.argv[2]
config = Config()

interface_path = ['interfaces'] + Section.get_config_path(interface).split()

systemdV4_service = f'dhclient@{interface}.service'
systemdV6_service = f'dhcp6c@{interface}.service'
if in_out == 'out':
    # Interface moved state to down
    if is_systemd_service_active(systemdV4_service):
        cmd(f'systemctl stop {systemdV4_service}')
    if is_systemd_service_active(systemdV6_service):
        cmd(f'systemctl stop {systemdV6_service}')
elif in_out == 'in':
    if config.exists_effective(interface_path + ['address']):
        tmp = config.return_effective_values(interface_path + ['address'])
        # Always (re-)start the DHCP(v6) client service. If the DHCP(v6) client
        # is already running - which could happen if the interface is re-
        # configured in operational down state, it will have a backoff
        # time increasing while not receiving a DHCP(v6) reply.
        #
        # To make the interface instantly available, and as for a DHCP(v6) lease
        # we will re-start the service and thus cancel the backoff time.
        if 'dhcp' in tmp:
            cmd(f'systemctl restart {systemdV4_service}')
        if 'dhcpv6' in tmp:
            cmd(f'systemctl restart {systemdV6_service}')