OpenWRT 3G connection checker & logger

A 3G connection is normally not very stable - so we need something to periodically check it & reconnect when needed. I also wanted a summary email at the end of each day with the total traffic per client. I'm using the following settings/scripts:

Edit /etc/crontabs/root (create if not existing):

# send stats & disconnect 3G at 23:00 everyday.
# check the connection every 5 minutes between 5:00 and 23:00 and reconnect if needed
# reboot at 5:00 if /tmp/stats.msg doesn't exist - will be sent in checkconnect
*/5 5-22 * * * /usr/bin/checkconnection
0 5 * * * if [ ! -s /tmp/stats.msg ]; then reboot ; fi
0 23 * * * /usr/bin/sendstats && ifdown wan

The first line will run /usr/bin/checkconnection every 5 minutes between 5:00 and 22:59. Then at 23:00 the  day's statistics will be emailed and the 3G connection disconnected. The next morning at 5:00 it first checks if the email was sucessfully sent at 23:00, if so it will reboot the router (seems to be more stable if you reboot it every day), and part of the reboot will be to enable the 3G connection. If the email was not sent, checkconnection will reopen the connection and try to re-send. On success it will reboot the router.

The router automatically updates the date & time with a NTP server. Make sure you have the correct  timezone defined in /etc/config/system.

The scripts:
/usr/bin/checkconnection: It first updates the 3g stats. Then if we have an email to be sent, we first send it (replace from@addres.com with your from address, to@address.com with your to address and smtp.com with your smtp server):

# write 3g stats to logfile
/usr/bin/wrtbwmon setup 3g-wan
/usr/bin/wrtbwmon update /tmp/log/wrtbwmon
# try to send out email if it's still pending
if [ -s /tmp/stats.msg ];
then
  cat /tmp/stats.msg | mini_sendmail -ffrom@address.com -ssmtp.com to@address.com
  if [ $? -eq 0 ] ; then reboot ; fi
fi
# if 3g is connected, we have nothing to do
if
  ifconfig 3g-wan
  then
  # sometimes ifconfig 3g-wan shows information, but 3g-wan is not running
  if
    ifconfig | grep 3g-wan
    then
      exit 0
  fi
  # if we reach this, it means we need to restart 3g-wan
  ifdown wan
fi
# if we get to this point, it means 3g is not connected
# check if we can access /dev/ttyUSB2 - if not reset the USB device
# and reconnect
if [ -e /dev/ttyUSB2 ];
then
  ifup wan
else
  /usr/bin/usb_modeswitch -c /etc/usb_modeswitch.d/custom
  sleep 10
  ifup wan
fi

/etc/usb_modeswitch.d/custom: It seems usb_modeswitch does not always recognise the USB modem, so we need sometimes need to no manually do a modeswitch. This is for a Huawei E1752 - search the web for other modems:

DefaultVendor=0x12d1
DefaultProduct=0x1446
TargetVendor=0x12d1
TargetProdct=0x1001
MessageEndpoint=0x01
MessageContent="55534243000000000000000000000011060000000000000000000000000000"

/usr/bin/wrtbwmon: This was originally taken from http://code.google.com/p/wrtbwmon/ and modified to suit my needs.

#!/bin/sh
#
# Traffic logging tool for OpenWRT-based routers
#
# Created by Emmanuel Brucy (e.brucy AT qut.edu.au)
#
# Based on work from Fredrik Erlandsson (erlis AT linux.nu)
# Based on traff_graph script by twist - http://wiki.openwrt.org/RrdTrafficWatch
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
LAN_IFACE=${2} || $(nvram get lan_ifname)
lock()
{
        while [ -f /tmp/wrtbwmon.lock ]; do
                if [ ! -d /proc/$(cat /tmp/wrtbwmon.lock) ]; then
                        echo "WARNING : Lockfile detected but process $(cat /tmp/wrtbwmon.lock) does not exist !"
                        rm -f /tmp/wrtbwmon.lock
                fi
                sleep 1
        done
        echo $$ > /tmp/wrtbwmon.lock
}
unlock()
{
        rm -f /tmp/wrtbwmon.lock
}
case ${1} in
"setup" )
        #Create the RRDIPT CHAIN (it doesn't matter if it already exists).
        iptables -N RRDIPT 2> /dev/null
        #Add the RRDIPT CHAIN to the FORWARD chain (if non existing).
        iptables -L FORWARD --line-numbers -n | grep "RRDIPT" | grep "1" > /dev/null
        if [ $? -ne 0 ]; then
                iptables -L FORWARD -n | grep "RRDIPT" > /dev/null
                if [ $? -eq 0 ]; then
                        echo "DEBUG : iptables chain misplaced, recreating it..."
                        iptables -D FORWARD -j RRDIPT
                fi
                iptables -I FORWARD -j RRDIPT
        fi
        #For each host in the ARP table
        grep 192.168.1 /proc/net/arp | while read IP TYPE FLAGS MAC MASK IFACE ;
        do
                #Add iptable rules (if non existing).
                iptables -nL RRDIPT | grep "${IP} " > /dev/null
                if [ $? -ne 0 ]; then
                        echo "DEBUG : adding rule for IP ${IP}"
                        iptables -I RRDIPT -d ${IP} -j RETURN -i ${2}
                        iptables -I RRDIPT -s ${IP} -j RETURN -o ${2}
                fi
        done
        ;;
"update" )
        [ -z "${2}" ] && echo "ERROR : Missing argument 2" && exit 1
        # Uncomment this line if you want to abort if database not found
        # [ -f "${2}" ] || exit 1
        # Create an empty file if not existing
        [ -f "${2}" ] || touch ${2}
        lock
        #Read and reset counters
        iptables -L RRDIPT -vnxZ -t filter > /tmp/traffic_$$.tmp
        grep -v "0x0" /proc/net/arp | grep -v 'IP address' | grep -v eth0.1 | while read IP TYPE FLAGS MAC MASK IFACE
        do
                #Add new data to the graph. Count in Kbs to deal with 16 bits signed values (up to 2G only)
                #Have to use temporary files because of crappy busybox shell
                grep ${IP} /tmp/traffic_$$.tmp | while read PKTS BYTES TARGET PROT OPT IFIN IFOUT SRC DST
                do
                        [ "${DST}" = "${IP}" ] && echo $((${BYTES}/1000)) > /tmp/in_$$.tmp
                        [ "${SRC}" = "${IP}" ] && echo $((${BYTES}/1000)) > /tmp/out_$$.tmp
                done
                IN=$(cat /tmp/in_$$.tmp)
                OUT=$(cat /tmp/out_$$.tmp)
                rm -f /tmp/in_$$.tmp
                rm -f /tmp/out_$$.tmp
                if [ ${IN} -gt 0 -o ${OUT} -gt 0 ];  then
                        echo "DEBUG : New traffic for ${MAC} since last update : ${IN}k:${OUT}k"
                        LINE=$(grep ${MAC} ${2})
                        if [ -z "${LINE}" ]; then
                                echo "DEBUG : ${MAC} is a new host !"
                                PEAKUSAGE_IN=0
                                PEAKUSAGE_OUT=0
                                OFFPEAKUSAGE_IN=0
                                OFFPEAKUSAGE_OUT=0
                        else
                                PEAKUSAGE_IN=$(echo ${LINE} | cut -f2 -s -d, )
                                PEAKUSAGE_OUT=$(echo ${LINE} | cut -f3 -s -d, )
                                OFFPEAKUSAGE_IN=$(echo ${LINE} | cut -f4 -s -d, )
                                OFFPEAKUSAGE_OUT=$(echo ${LINE} | cut -f5 -s -d, )
                        fi
                        if [ "${3}" = "offpeak" ]; then
                                OFFPEAKUSAGE_IN=$((${OFFPEAKUSAGE_IN}+${IN}))
                                OFFPEAKUSAGE_OUT=$((${OFFPEAKUSAGE_OUT}+${OUT}))
                        else
                                PEAKUSAGE_IN=$((${PEAKUSAGE_IN}+${IN}))
                                PEAKUSAGE_OUT=$((${PEAKUSAGE_OUT}+${OUT}))
                        fi
                        grep -v "${MAC}" ${2} > /tmp/db_$$.tmp
                        mv /tmp/db_$$.tmp ${2}
                        echo ${MAC},${PEAKUSAGE_IN},${PEAKUSAGE_OUT},${OFFPEAKUSAGE_IN},${OFFPEAKUSAGE_OUT},$(date "+%d-%m-%Y %H:%M") >> ${2}
                fi
        done
        #Free some memory
        rm -f /tmp/*_$$.tmp
        unlock
        ;;
"publish" )
        [ -z "${2}" ] && echo "ERROR : Missing argument 2" && exit 1
        [ -z "${3}" ] && echo "ERROR : Missing argument 3" && exit 1
        USERSFILE="/etc/dnsmasq.conf"
        [ -f "${USERSFILE}" ] || USERSFILE="/tmp/dnsmasq.conf"
        [ -z "${4}" ] || USERSFILE=${4}
        [ -f "${USERSFILE}" ] || USERSFILE="/dev/null"
        # first do some number crunching - rewrite the database so that it is sorted
        lock
        mkdir -p /tmp/www
        touch /tmp/sorted_$$.tmp
        cat ${2} | while IFS=, read MAC PEAKUSAGE_IN PEAKUSAGE_OUT OFFPEAKUSAGE_IN OFFPEAKUSAGE_OUT LASTSEEN
        do
                echo ${PEAKUSAGE_IN},${PEAKUSAGE_OUT},${OFFPEAKUSAGE_IN},${OFFPEAKUSAGE_OUT},${MAC},${LASTSEEN} >> /tmp/sorted_$$.tmp
        done
        unlock
        # create HTML page
        echo "

Total Usage :

" >> ${3}
        echo "" >> ${3}
        echo "

User	Peak download	Peak upload	Offpeak download	Offpeak upload	Last seen

" >> ${3}
        echo "
This page was generated on `date`" 2>&1 >> ${3}
        echo "" >> ${3}
        #Free some memory
        rm -f /tmp/*_$$.tmp
        ;;
*)
        echo "Usage : $0 {setup|update|publish} [options...]"
        echo "Options : "
        echo "   $0 setup"
        echo "   $0 update database_file [offpeak]"
        echo "   $0 publish database_file path_of_html_report [user_file]"
        echo "Examples : "
        echo "   $0 setup"
        echo "   $0 update /tmp/usage.db offpeak"
        echo "   $0 publish /tmp/usage.db /www/user/usage.htm /jffs/users.txt"
        echo "Note : [user_file] is an optional file to match users with their MAC address"
        echo "       Its format is : 00:MA:CA:DD:RE:SS,username , with one entry per line"
        exit
        ;;
esac

/usr/bin/sendstats: Replace from@address.com with your from address, to@addres.com with your to address, and smtp.com with your smtp server.

echo "From: OpenWRT router " > /tmp/stats.msg
echo "To: to@address.com" >> /tmp/stats.msg
echo "Subject: Router statistics" >> /tmp/stats.msg
echo "" >> /tmp/stats.msg
echo "Uptime:" >> /tmp/stats.msg
uptime >> /tmp/stats.msg
echo "" >> /tmp/stats.msg
echo "wrtbwmon:" >> /tmp/stats.msg
cat /tmp/log/wrtbwmon >> /tmp/stats.msg
echo "" >> /tmp/stats.msg
echo "PPP log:" >> /tmp/stats.msg
cat /var/log/ppp >> /tmp/stats.msg
echo "" >> /tmp/stats.msg
#echo "/proc/net/arp:" >> /tmp/stats.msg
#cat /proc/net/arp >> /tmp/stats.msg
#echo "" >> /tmp/stats.msg
echo "ifconfig:" >> /tmp/stats.msg
ifconfig >> /tmp/stats.msg
echo "" >> /tmp/stats.msg
#echo "logread:" >> /tmp/stats.msg
#logread >> /tmp/stats.msg
rm /tmp/log/wrtbwmonrm /var/log/ppp
cat /tmp/stats.msg | mini_sendmail -ffrom@address.com -ssmtp.com to@address.com
if [ $? -eq 0 ] ; then rm /tmp/stats.msg ; fi

/etc/ppp/ip-up.d/3glog: (everytime the 3g connects, write the date & time to a log file)

#!/bin/sh
logfile=/var/log/ppp
echo "`date` Connected $0 $1 $2 $3 $4 $5 $6" >> $logfile
# setup bandwidth monitoring
/usr/bin/wrtbwmon setup 3g-wan

/etc/ppp/ip-down.d/3glog: (everytime the 3g disconnects, write the date & time & total bytes sent to a log file)

#!/bin/sh
logfile=/var/log/ppp
echo "`date` Disconnected $0 $1 $2 $3 $4 $5 $6" >> $logfile
logread | tail | grep Sent >> $logfile