A silly little watchdog script to monitor my wifi connection and reset it

internet_watchdog.sh

#!/bin/sh

#Host to ping to check pingability, by default it is the default gateway
PING_HOST=$(ip route show default | awk '/default/ {print $3}')
PING_INTERVAL=10
PING_TIMEOUT=5

#Number of consecutive ping successes to note that the server is up
SUCCESS_ALERT_COUNT=1

#Number of consecutive ping failures to note that the server is down
FAILURE_ALERT_COUNT=3

function ON_PING_SUCCESS {
	echo "Network is up"
}

function ON_PING_FAILURE {
	echo "Network is down"
	rmmod iwldvm
	rmmod iwlwifi
	modprobe iwlwifi
}



#--------------------------------------------------------- Implementation

_SUCCESS_COUNT=0
_FAIL_COUNT=0

_LAST_STATE=''
_CURRENT_STATE=''

echo "Starting Internet Watchdog..."

while true; do
	ping -q -c 1 -W $PING_TIMEOUT $PING_HOST &> /dev/null

	if [ $? -eq 0 ]; then
		_SUCCESS_COUNT=`expr $_SUCCESS_COUNT + 1`
		_FAIL_COUNT=0
	else
		_SUCCESS_COUNT=0
		_FAIL_COUNT=`expr $_FAIL_COUNT + 1`
	fi

	if [ $_SUCCESS_COUNT -eq $SUCCESS_ALERT_COUNT ]; then
		_CURRENT_STATE="SUCCESS"
	fi

	if [ $_FAIL_COUNT -eq $FAILURE_ALERT_COUNT ]; then
		_CURRENT_STATE="FAILURE"
	fi

	if [[ $_CURRENT_STATE != $_LAST_STATE ]]; then
		if [[ $_CURRENT_STATE == "SUCCESS" ]]; then
			ON_PING_SUCCESS
		else
			ON_PING_FAILURE
		fi
		_LAST_STATE=$_CURRENT_STATE
	fi

	sleep $PING_INTERVAL
done;