#!/bin/sh
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#
# Title:     check_wlan0
#
# Script checks to see if WiFi has a network IP and if not
# restart WiFi
#
# Uses a lock file which prevents the script from running more
# than one at a time.  If lockfile is old, it removes it
#
# Instructions:
#
# o Install where you want to run it from like /usr/local/bin
# o chmod 0755 /usr/local/bin/check_wlan0.sh
# o Add to crontab
#
# Run Every 5 mins - Seems like ever min is over kill unless
# this is a very common problem.  If once a min change */5 to *
# once every 2 mins */5 to */2 ...
#
# */5 * * * * /usr/local/bin/check_wlan0.sh
#
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# Settings
# Where and what you want to call the Lockfile
lockfile='/var/run/check_wlan0.pid'
#logger "logfile: $lockfile"
# Which Interface do you want to check/fix
# Example: wlan0, eth0, etc.
wlan='wlan0'
##################################################################
echo
echo "check: $wlan"
#date
echo

# Check to see if there is a lock file
if [ -e $lockfile ]; then
    # A lockfile exists... Lets check to see if it is still valid
    pid=`cat $lockfile`
    if kill -0 &>1 > /dev/null $pid; then
        # Still Valid... lets let it be...
        echo "Process still running, Lockfile valid"
        exit 1
    else
        # Old Lockfile, Remove it
        echo "Old lockfile, Removing Lockfile"
        rm $lockfile
    fi
fi
# If we get here, set a lock file using our current PID#
#echo "Setting Lockfile"
echo $$ > $lockfile

# We can perform check
echo "Performing Network check for $wlan"
#if ifconfig $wlan | grep -q "inet addr:" ; then
if /sbin/ifconfig $wlan | /bin/grep "inet addr:" ; then
    echo "Network is Okay"
    #logger "Network is Okay"
else
    echo "Network connection down! Attempting reconnection."
    /sbin/ifdown $wlan
    logger "Network connection down! Attempting reconnection."
    logger "ifdown $wlan - sleep 5"
    /bin/sleep 5
    /sbin/ifup --force $wlan
    /sbin/ifconfig $wlan | grep "inet addr"
    logger `/sbin/ifconfig $wlan | grep "inet addr"`
    /bin/sleep 5
fi

echo
echo "Current Setting:"
ifconfig $wlan | grep "inet addr:"
echo

# Check is complete, Remove Lock file and exit
echo "process is complete, removing lockfile"
rm $lockfile
exit 0

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# End of Script
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