#!/usr/bin/env python3
#
# Copyright (C) 2020 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/>.

import re
from sys import exit, argv

if len(argv) == 2:
    len = len(argv[1])
    # VRF instance name must be 16 characters or less, python range needs to be
    # extended by one
    if not len in range(1, 17):
        exit(1)

    # Treat loopback interface "lo" explicitly. Adding "lo" explicitly to the
    # following regex pattern would deny any VRF name starting with lo - thuse
    # local-vrf would be illegal - and that we do not want.
    if argv[1] == "lo":
        exit(1)

    # VRF instances should not be named after regular interface names like bond0,
    # br10 and so on - this can cause a lot of confusion/trouble
    pattern = "^(?!(bond|br|dum|eth|lan|eno|ens|enp|enx|gnv|ipoe|l2tp|l2tpeth|" \
              "vtun|ppp|pppoe|peth|tun|vti|vxlan|wg|wlan|wlm)\d+(\.\d+(v.+)?)?$).*$"
    if re.match(pattern, argv[1]):
        exit(0)

exit(1)