Keep WAN Up with DD-WRT Routers

# Clean nvram at startup
for line in `nvram show  | grep =$ `;
do
   var=${line%*=};
   nvram unset $var;
done &

# Keep bridge connection alive
INTERVAL=10
while true; do
  while [ \! $gw ]; do
    sleep 30
    route -n > /tmp/routes
    while read dest gw foo; do
      if [ $dest = "0.0.0.0" ]; then
        break
      fi
    done < /tmp/routes
  done
  echo "[`date`] Auto-Repair: Default Gateway is $gw" >> /tmp/wan-restarts.log
  while ping -qc 2 $gw > /dev/null ; do
    sleep $INTERVAL
  done
  echo "[`date`] Auto-Repair: Gateway Down! Restarting WAN" >> /tmp/wan-restarts.log
  kill -USR1 `cat /var/run/udhcpc.pid`
  unset gw
  if [ `wc -l /tmp/wan-restarts.log | cut -d ' ' -f1` -gt 20 ];
  then
    tail -n 20 /tmp/wan-restarts.log > /tmp/wan-restarts.log
  fi
done &