#!/bin/bash #Copyright Angsuman Chakraborty, Taragana. Permission is granted for personal, non-commercial use. #The script may not be re-distributed in any form without written permission from Angsuman Chakraborty ( angsuman@taragana.com ). #The script may be modified for personal use. #THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE AUTHOR ACCEPTS NO RESPONSIBILITY IN ANY CONCEIVABLE MANNER. # Conventionally 0 indicates success in this script. # Time between checks in seconds SLEEPTIME=10 #IP Address or domain name to ping. The script relies on the domain being #pingable and always available TESTIP=www.yahoo.com #Ping timeout in seconds TIMEOUT=2 # External interfaces EXTIF1=eth0 EXTIF2=ra0 #IP address of external interfaces. This is not the gateway address. IP1=192.168.1.104 IP2=192.168.0.103 #Gateway IP addresses. This is the first (hop) gateway, could be your router IP #address if it has been configured as the gateway GW1=192.168.1.1 GW2=192.168.0.1 # Relative weights of routes. Keep this to a low integer value. I am using 4 # for TATA connection because it is 4 times faster W1=1 W2=1 # Broadband providers name; use your own names here. NAME1=linksys NAME2=newbies #No of repeats of success or failure before changing status of connection SUCCESSREPEATCOUNT=4 FAILUREREPEATCOUNT=1 # Do not change anything below this line # Last link status indicates the macro status of the link we determined. This is down initially to force routing change upfront. Don't change these values. LLS1=1 LLS2=1 # Last ping status. Don't change these values. LPS1=1 LPS2=1 # Current ping status. Don't change these values. CPS1=1 CPS2=1 # Change link status indicates that the link needs to be changed. Don't change these values. CLS1=1 CLS2=1 # Count of repeated up status or down status. Don't change these values. COUNT1=0 COUNT2=0 while : ; do sudo ping -W $TIMEOUT -I $IP1 -c 1 $TESTIP > /dev/null 2>&1 RETVAL=$? if [ $RETVAL -ne 0 ]; then echo $NAME1 Down CPS1=1 else CPS1=0 fi if [ $LPS1 -ne $CPS1 ]; then echo Ping status changed for $NAME1 from $LPS1 to $CPS1 COUNT1=1 else if [ $LPS1 -ne $LLS1 ]; then COUNT1=`expr $COUNT1 + 1` fi fi if [[ $COUNT1 -ge $SUCCESSREPEATCOUNT || ($LLS1 -eq 0 && $COUNT1 -ge $FAILUREREPEATCOUNT) ]]; then echo Uptime status will be changed for $NAME1 from $LLS1 CLS1=0 COUNT1=0 if [ $LLS1 -eq 1 ]; then LLS1=0 else LLS1=1 fi else CLS1=1 fi LPS1=$CPS1 sudo ping -W $TIMEOUT -I $IP2 -c 1 $TESTIP > /dev/null 2>&1 RETVAL=$? if [ $RETVAL -ne 0 ]; then echo $NAME2 Down CPS2=1 else CPS2=0 fi if [ $LPS2 -ne $CPS2 ]; then echo Ping status changed for $NAME2 from $LPS2 to $CPS2 COUNT2=1 else if [ $LPS2 -ne $LLS2 ]; then COUNT2=`expr $COUNT2 + 1` fi fi if [[ $COUNT2 -ge $SUCCESSREPEATCOUNT || ($LLS2 -eq 0 && $COUNT2 -ge $FAILUREREPEATCOUNT) ]]; then echo Uptime status will be changed for $NAME2 from $LLS2 CLS2=0 COUNT2=0 if [ $LLS2 -eq 1 ]; then LLS2=0 else LLS2=1 fi else CLS2=1 fi LPS2=$CPS2 if [[ $CLS1 -eq 0 || $CLS2 -eq 0 ]]; then if [[ $LLS1 -eq 1 && $LLS2 -eq 0 ]]; then echo Switching to $NAME2 ip route replace default scope global via $GW2 dev $EXTIF2 elif [[ $LLS1 -eq 0 && $LLS2 -eq 1 ]]; then echo Switching to $NAME1 ip route replace default scope global via $GW1 dev $EXTIF1 elif [[ $LLS1 -eq 0 && $LLS2 -eq 0 ]]; then echo Restoring default load balancing ip route replace default scope global nexthop via $GW1 dev $EXTIF1 weight $W1 nexthop via $GW2 dev $EXTIF2 weight $W2 fi fi sleep $SLEEPTIME done