#!/bin/sh
#
# Copyright (C) VyOS Inc.
#
# 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/>.

# Passes only if $1 is a net device that exists on the system and is not a
# VRF. Used as a fallback alongside a naming-pattern regex, so a currently
# existing device is accepted as a physical/logical interface only if it is
# not a VRF (VRFs are real net devices but must never be accepted where an
# interface is expected).

case "$1" in
    ""|.|..|*/*)
        echo "Error: $1 does not exist"
        exit 1
        ;;
esac

if [ ! -d "/sys/class/net/$1" ]; then
    echo "Error: $1 does not exist"
    exit 1
fi

if ip vrf show "$1" >/dev/null 2>&1; then
    echo "Error: $1 is a VRF, not a network interface"
    exit 1
fi

exit 0