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#!/bin/bash
# $Id: alcasar-watchdog.sh 1867 2016-05-04 12:22:08Z raphael.pion $
# alcasar-watchdog.sh
# by Rexy
# This script is distributed under the Gnu General Public License (GPL)
# Ce script prévient les usagers de l'indisponibilité de l'accès Internet
# il déconnecte les usagers dont
# - les équipements réseau ne répondent plus
# - les adresses MAC sont usurpées
# This script tells users that Internet access is down
# it logs out users whose
# - PCs are quiet
# - MAC address is used by other systems (usurped)
CONF_FILE="/usr/local/etc/alcasar.conf"
EXTIF=`grep ^EXTIF= $CONF_FILE|cut -d"=" -f2` # EXTernal InterFace
INTIF=`grep ^INTIF= $CONF_FILE|cut -d"=" -f2` # INTernal InterFace
private_ip_mask=`grep PRIVATE_IP= $CONF_FILE|cut -d"=" -f2`
private_ip_mask=${private_ip_mask:=192.168.182.1/24}
PRIVATE_IP=`echo "$private_ip_mask" |cut -d"/" -f1` # @ip du portail (côté LAN)
PRIVATE_IP=${PRIVATE_IP:=192.168.182.1}
tmp_file="/tmp/watchdog.txt"
DIR_WEB="/var/www/html"
Index_Page="$DIR_WEB/index.php"
IPTABLES="/sbin/iptables"
TUNIF="tun0" # listen device for chilli daemon
OLDIFS=$IFS
IFS=$'\n'
function lan_down_alert ()
# users are redirected on ALCASAR IP address if a LAN problem is detected
{
case $LAN_DOWN in
"1")
logger "$EXTIF (WAN card) link down"
echo "$EXTIF (WAN card) link down"
/bin/sed -i "s?diagnostic =.*?diagnostic = \"$EXTIF (WAN card) link down\";?g" $Index_Page
;;
"2")
logger "can't contact the default router"
echo "can't contact the default router"
/bin/sed -i "s?diagnostic =.*?diagnostic = \"can't contact the default router\";?g" $Index_Page
;;
esac
net_pb=`grep "network_pb = True;" $Index_Page|wc -l`
if [ $net_pb = "0" ] # user alert (only the first time)
then
/bin/sed -i "s?^\$network_pb.*?\$network_pb = True;?g" $Index_Page
$IPTABLES -I PREROUTING -t nat -i $TUNIF -p udp --dport domain -j REDIRECT --to-port 56
fi
}
function lan_test ()
# LAN connectiivity testing
{
watchdog_process=`ps -C alcasar-watchdog.sh|wc -l`
if [[ $(expr $watchdog_process) -gt 3 ]]
then
echo "ALCASAR watchdog is already running"
exit 0
fi
# EXTIF testing
LAN_DOWN="0"
if [ `/sbin/ip link | grep $EXTIF|grep "NO-CARRIER" | wc -l` -eq "1" ]
then
LAN_DOWN="1"
fi
# Default GW testing
if [ $LAN_DOWN -eq "0" ]
then
IP_GW=`/sbin/ip route list|grep ^default|cut -d" " -f3`
arp_reply=`/usr/sbin/arping -I$EXTIF -c1 $IP_GW|grep response|cut -d" " -f2`
if [ $arp_reply -eq "0" ]
then
LAN_DOWN="2"
fi
fi
# if LAN pb detected, users are warned
if [ $LAN_DOWN != "0" ]
then
lan_down_alert
# else switch in normal mode
else
echo "Internet access is OK for now"
net_pb=`grep "network_pb = True;" $Index_Page|wc -l`
if [ $net_pb != "0" ]
then
/bin/sed -i "s?^\$network_pb.*?\$network_pb = False;?g" $Index_Page
$IPTABLES -D PREROUTING -t nat -i $TUNIF -p udp --dport domain -j REDIRECT --to-port 56
fi
fi
}
usage="Usage: alcasar-watchdog.sh {-lt --lan_test}"
case $1 in
-\? | -h* | --h*)
echo "$usage"
exit 0
;;
-lt | --lan_test)
lan_test
exit 0
;;
*)
lan_test
# read file that contains IP address of quiet equipments
if [ -e $tmp_file ]; then
cat $tmp_file | while read noresponse
do
noresponse_ip=`echo $noresponse | cut -d" " -f1`
noresponse_mac=`echo $noresponse | cut -d" " -f2`
noresponse_user=`echo $noresponse | cut -d" " -f3`
arp_reply=`/usr/sbin/arping -b -I$INTIF -s$PRIVATE_IP -c1 -w4 $noresponse_ip|grep "Unicast reply"|wc -l`
if [[ $(expr $arp_reply) -eq 0 ]]
then
#on vide les ip inactifs de l'ipset not_auth_yet
ipset del not_auth_yet $noresponse_ip
logger "alcasar-watchdog $noresponse_ip ($noresponse_mac) can't be contact. Alcasar disconnects the user ($noresponse_user)."
/usr/sbin/chilli_query logout $noresponse_mac
if [[ $noresponse_user == $noresponse_mac ]] # for @mac auth equipments, we must remove the arp entry
then /usr/sbin/chilli_query dhcp-release $noresponse_mac
fi
fi
done
rm $tmp_file
fi
# process each equipment known by chilli
for system in `/usr/sbin/chilli_query list |grep -v "\.0\.0\.0"`
do
active_ip=`echo $system |cut -d" " -f2`
active_session=`echo $system |cut -d" " -f5`
active_mac=`echo $system | cut -d" " -f1`
active_user=`echo $system |cut -d" " -f6`
# process only equipment with an authenticated user
if [[ $(expr $active_session) -eq 1 ]]
then
arp_reply=`/usr/sbin/arping -b -I$INTIF -s$PRIVATE_IP -c2 -w4 $active_ip|grep "Unicast reply"|wc -l`
# store @IP of quiet equipments
if [[ $(expr $arp_reply) -eq 0 ]]
then
echo "$active_ip $active_mac $active_user" >> $tmp_file
fi
# disconnect users whose equipement is usurped (@MAC)
if [[ $(expr $arp_reply) -gt 2 ]]
then
echo "$(date "+[%x-%X] : ")alcasar-watchdog : $active_ip is usurped ($active_mac). Alcasar disconnect the user ($active_user)." >> /var/Save/security/watchdog.log
logger "alcasar-watchdog : $active_ip is usurped ($active_mac). Alcasar disconnect the user ($active_user)."
/usr/sbin/chilli_query logout $active_mac
chmod 644 /var/Save/security/watchdog.log
fi
fi
done
;;
esac
IFS=$OLDIFS