Openwrt watchdog script

dog.sh

#!/bin/sh

# save dog.sh in /root/dog.sh. 
# You can use winscp with scp protocol to do this.
# Using ssh set executation permission and replace the crontab:
# chmod +x /root/dog.sh
# echo "* * * * * /root/dog.sh" | crontab -

# fix wpad / wpad-mini / hostapd stop working bug
logread -l 100 | grep -n "IEEE 802.11: did not acknowledge authentication response"
if [ $? -eq 0 ]; then
   /etc/init.d/network restart
fi

# fix kernel bug
n=0
while [ 1 ]; do
  #ping with timeout 10 seconds
  ping -c 1 -W 10 -w 10 8.8.8.8
  ret=$?

  echo ping result $ret
  if [ $ret -eq 0 ]; then
    echo ping ok
    exit 0
  else 
    echo ping fail
    n=$((n+1))
    # when wan-dhcp fail, 
    # net is unreachable and ping return without any delay
    # using sleep 1 avoid fail count overflow too fast
    sleep 1
  fi

  echo fail counter $n
  if [ $n -gt 60 ]; then
    #Trying to restart WAN interface
	ifdown wan && ifup wan
	#waiting for 10sec to reconnect
	sleep 10
	#checking internet now
	ping -c 1 -W 10 -w 10 8.8.8.8
	ret=$?
	if [ $ret -eq 0 ]; then
		echo ping ok
		exit 0
	else
		echo all failed rebooting now
	    reboot
    fi
  fi
done