#! /bin/bash
DEV=$1

if [ ! -d /tmp/openvpn ]; then
  mkdir /tmp/openvpn
fi
CACHE_NAMESERVER="/tmp/$DEV.nameserver"
echo -n "" > $CACHE_NAMESERVER

TEMP_LOG="/tmp/openvpn_dns.log"
echo "DNS openvpn" > "$TEMP_LOG"
echo -e "${foreign_option_1}\n${foreign_option_2}\n$foreign_option_3" >> "$TEMP_LOG"

rm -rf /tmp/resolv.conf
touch /tmp/resolv.conf
dns=dns
for opt in ${!foreign_option_*}
do
  eval "echo \$$opt" >> "$TEMP_LOG"
  eval "dns=\${$opt#dhcp-option DNS }"
  if [[ $dns =~ [0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3} ]]; then
    if [ ! -f /etc/resolv.conf.default ]; then
      cp /etc/resolv.conf /etc/resolv.conf.default
    fi

    # don't add "local" dns server
    #cat /etc/resolv.conf | grep -v ^# | grep -v ^nameserver > /tmp/resolv.conf

    echo "nameserver $dns" >> /tmp/resolv.conf
    echo $dns >> $CACHE_NAMESERVER
    #cat /etc/resolv.conf | grep -v ^# | grep -v "nameserver $dns" | grep nameserver >> /tmp/resolv.conf

  fi
done

if [ -e "/tmp/resolv.conf" ]; then
  mv /tmp/resolv.conf /etc/resolv.conf
fi