# Update domain name server IPv4 addresses and
# restart udhcpd on reconfiguration of the interface.

RESOLV_CONF="/etc/resolv.conf"
UDHCPD_CONF="/tmp/udhcpd.conf"
UDHCPD_CONF_TEMPLATE="/etc/udhcpd.conf"

if $if_configured; then
  [ ! -f "$RESOLV_CONF" ] && return 

  # Filter resolv.conf to get the IPv4 name servers
  # only.
  dns=$(grep -F nameserver $RESOLV_CONF | cut -c 12- | grep -E "^[0-9\.]*$")

  cat $UDHCPD_CONF_TEMPLATE \
    | sed "s!%%DNS%%!$dns!" \
    > $UDHCPD_CONF
  chmod a+r "$UDHCPD_CONF"
  service udhcpd --ifstarted restart
fi