#!/bin/bash
#
# Parses DHCP options from openvpn to update resolv.conf
# To use set as 'up' and 'down' script in your openvpn *.conf:
# up /etc/openvpn/update-resolv-conf
# down /etc/openvpn/update-resolv-conf
#
# Used snippets of resolvconf script by Thomas Hood and Chris Hanson.
# Licensed under the GNU GPL.  See /usr/share/common-licenses/GPL.
#
# Example envs set from openvpn:
#
#     foreign_option_1='dhcp-option DNS 193.43.27.132'
#     foreign_option_2='dhcp-option DNS 193.43.27.133'
#     foreign_option_3='dhcp-option DOMAIN be.bnc.ch'
#

if [ ! -x /sbin/resolvconf ] ; then
    logger "[OpenVPN:update-resolve-conf] missing binary /sbin/resolvconf";
    exit 0;
fi

[ "$script_type" ] || exit 0
[ "$dev" ] || exit 0

split_into_parts()
{
    part1="$1"
    part2="$2"
    part3="$3"
}

case "$script_type" in
  up)
    NMSRVRS=""
    SRCHS=""
    foreign_options=$(printf '%s\n' ${!foreign_option_*} | sort -t _ -k 3 -g)
    for optionvarname in ${foreign_options} ; do
        option="${!optionvarname}"
        echo "$option"
        split_into_parts $option
        if [ "$part1" = "dhcp-option" ] ; then
            if [ "$part2" = "DNS" ] ; then
                NMSRVRS="${NMSRVRS:+$NMSRVRS }$part3"
            elif [ "$part2" = "DOMAIN" ] ; then
                SRCHS="${SRCHS:+$SRCHS }$part3"
            fi
        fi
    done
    R=""
    [ "$SRCHS" ] && R="search $SRCHS
"
    for NS in $NMSRVRS ; do
            R="${R}nameserver $NS
"
    done
    echo -n "$R" | /sbin/resolvconf -a "${dev}.openvpn"
    ;;
  down)
    /sbin/resolvconf -d "${dev}.openvpn"
    ;;
esac