ssid-changer.sh

#!/bin/sh

# At first some Definitions:

ONLINE_SSID='Freifunk'
OFFLINE_PREFIX='FF_OFFLINE_' # Use something short to leave space for the nodename

# Generate an Offline SSID with the first and last Part of the nodename to allow owner to recognise wich node is down
NODENAME=`uname -n`
if [ ${#NODENAME} -gt $((30 - ${#OFFLINE_PREFIX})) ] ; then #32 would be possible as well
	HALF=$(( (28 - ${#OFFLINE_PREFIX} ) / 2 ))
	SKIP=$(( ${#NODENAME} - $HALF ))
	OFFLINE_SSID=$OFFLINE_PREFIX${NODENAME:0:$HALF}...${NODENAME:$SKIP:${#NODENAME}} # use the first and last part of the nodename for nodes with long name
else
	OFFLINE_SSID="$OFFLINE_PREFIX$NODENAME"
fi

#Is there an active Gateway?
GATEWAY_TQ=`batctl gwl | grep "^=>" | awk -F'[()]' '{print $2}'| tr -d " "`
if [ $GATEWAY_TQ -gt 50 ];
then
	echo "Gateway TQ is $GATEWAY_TQ node is online"
	for HOSTAPD in $(ls /var/run/hostapd-phy*); do
		CURRENT_SSID=`grep "^ssid=$ONLINE_SSID" $HOSTAPD | cut -d"=" -f2`
		if [ $CURRENT_SSID == $ONLINE_SSID ]
		then
			echo "SSID $CURRENT_SSID is correct, noting to do"
			HUP_NEEDED=0
			break
		fi
		CURRENT_SSID=`grep "^ssid=$OFFLINE_SSID" $HOSTAPD | cut -d"=" -f2`
		if [ $CURRENT_SSID == $OFFLINE_SSID ]
		then
			logger -s -t "gluon-offline-ssid" -p 5 "TQ is $GATEWAY_TQ, SSID is $CURRENT_SSID, change to $ONLINE_SSID"
			sed -i s/^ssid=$CURRENT_SSID/ssid=$ONLINE_SSID/ $HOSTAPD
			HUP_NEEDED=1 # HUP here would be to early for dualband devices
		else
			echo "There is something wrong, did not find SSID $ONLINE_SSID or $OFFLINE_SSID"
		fi
	done
	
else
	echo "Gateway TQ is $GATEWAY_TQ node is considered offline"
	for HOSTAPD in $(ls /var/run/hostapd-phy*); do
		CURRENT_SSID=`grep "^ssid=$OFFLINE_SSID" $HOSTAPD | cut -d"=" -f2`
		if [ $CURRENT_SSID == $OFFLINE_SSID ]
		then
			echo "SSID $CURRENT_SSID is correct, noting to do"
			HUP_NEEDED=0
			break
		fi                                                                                      
		CURRENT_SSID=`grep "^ssid=$ONLINE_SSID" $HOSTAPD | cut -d"=" -f2`                       
		if [ $CURRENT_SSID == $ONLINE_SSID ]                                                    
		then                                                                                  
			logger -s -t "gluon-offline-ssid" -p 5 "TQ is $GATEWAY_TQ, SSID is $CURRENT_SSID, change to $OFFLINE_SSID"                           
			sed -i s/^ssid=$ONLINE_SSID/ssid=$OFFLINE_SSID/ $HOSTAPD                           
			HUP_NEEDED=1 # HUP here would be to early for dualband devices                  
		else                                                                                    
			echo "There is something wrong, did not find SSID $ONLINE_SSID or $OFFLINE_SSID"
		fi 
	done
fi

if [ $HUP_NEEDED == 1 ]; then
	killall -HUP hostapd # Send HUP to all hostapd um die neue SSID zu laden
	HUP_NEEDED=0
	echo "HUP!"
fi