#!/bin/sh

INTERVAL=5
PACKETS=1
HOST="8.8.4.4"
WAN1=wan
WAN2=3G
USINGWAN=1;
LOG="/root/failover.log"

echo "`date`: Failover script started." >> $LOG
while sleep $INTERVAL
do
	RET=`ping -w 2 -c $PACKETS $HOST 2>/dev/null | awk '/packets received/ {print $4}'`
	if [ "$RET" -ne "$PACKETS" ]; then		# Do we get a ping return? No? Go ahead....
		if [ "$USINGWAN" = "1" ]; then			# Switch from WAN to 3G
			if expr $VNS '<' $MAXMB 1>/dev/null; then
				ifup $WAN2
				USINGWAN=2
				echo "`date`: Changed active WAN port to 3G modem!" >> $LOG	# Log it
			fi
		fi
	else
		if [ "$USINGWAN" = "2" ]; then			# Switch from 3G to WAM
			ifdown $WAN2				# Shutdown WAN2
			ifup $WAN1				# Enable WAN1
			echo "nameserver 8.8.8.8" > /etc/resolv.conf
			USINGWAN=1
			echo "`date`: Changed active WAN port to DSL connection!" >> $LOG	# Log it
		fi
	fi
done;