openwrt watchdog: interface auto reconnect

watchdog.sh

#!/bin/sh
ip1=8.8.8.8
ip2=208.67.222.222
tries=3

if [[ -z $1 ]]; then
  logger -t watchdog "Missing interface name"
  exit 1
fi

interface=$1
ifname="$(uci get network.$interface.ifname 2> /dev/null)"

if [[ $? -eq 1 ]]; then
  logger -t watchdog "ifname not found in '$interface' interface"
  exit 1
fi

while [ $tries -ge 0 ]; do
  if /bin/ping -c 1 $ip1 -I $ifname > /dev/null 2>&1; then
    exit 0
  fi
  if /bin/ping -c 1 $ip2 -I $ifname > /dev/null 2>&1; then
    exit 0
  fi
  sleep 3
  tries=$((tries-1))
done

logger -t watchdog "Physical network interface '$ifname' is down: restart interface '$interface'"
ifdown $interface && ifup $interface
sleep 60
exit 0