Script to connect to a wifi AP, if we got a key in our database, use it

We got many keys for some wifi APs around, so we put them in a delimited text file like:

ap8599:5537801570
sd6980:5202140314
wq0858:5953230520

now, when we are around, we want a script that we can tell: "connect to ap6980 if you see it around, if you need a key, take it from the text file". Called without arguments, it scans all available networks, and tries to connect to all of the ones that we have a key or that are open.

This is our connection script:

#!/bin/bash

ap=$@
i=wlan0
en=0

#------------------------------------------------------------------------------------------------------------------
#  Scan for wireless networks, and pretty print the quality, the essid, and if we require encryption
#-----------------------------------------------------------------------------------------------------------------
scanw () {
i=$1
(       ifconfig $i up
        iwlist $i scan | egrep -i 'essid|freq|qual|encr' |nawk 'ORS=NR%4?" ":"\n"'| tr -s ' '| while read l;do
                AP=`echo "$l "|awk '{s=substr($0,index($0,"ESSID:")+7);print substr(s,1,index(s,"\"")-1)}'`
                EN=`echo "$l "|awk '{s=substr($0,index($0,"Encryption key:")+15);print substr(s,1,index(s," ")-1)}'`
                QU=`echo "$l "|awk '{s=substr($0,index($0,"Quality=")+8);print substr(s,1,index(s,"/")-1)}'`
                K=`grep "^$AP" keys.txt| awk -F':' '{ print $2 }'`
                echo "$QU:$EN:$AP:$i:$K"
        done
) | sort -n
}

#-----------------------------------------------------------------------------------------------------------------
# Connect to the accespoint determined by the "$ap" variable
#-----------------------------------------------------------------------------------------------------------------
conn(){
L=`grep -i "$ap" ~/keys.txt| head -1`
C=`echo -n $L | wc -c`
indb=1
if [ $C -lt 1 ];then
#       echo "------------- WARNING: AP $ap not found in database"
        indb=0
fi
S=`grep "$ap" /tmp/scan.$$|wc -c`
if [ $S -lt 1 ];then
        echo "------------- ERROR: AP $ap is not in range, cannot connect"
        exit 1
fi
if [ $indb -eq 1 ];then
        #---if we found an accesspoint in our database work with it
        AP=`echo $L | awk -F':' '{ print $1 }'`
        K=`echo $L | awk -F':' '{ print $2 }'`
        echo "------------- Connecting to $AP with key $K"
        iwconfig $i mode managed key $K essid "$AP" rate auto
else
        AP=`grep "$ap" /tmp/scan.$$|awk -F':' '{ print $3 }'`
        en=`grep "$AP" /tmp/scan.$$|awk -F':' '{ print $2 }'`
        if [ $en == "off" ];then
                echo "------------- Connecting to $AP without key"
                iwconfig $i mode managed key off essid "$AP" rate auto
        else
                echo "------------ ERROR: Encryption needed for $AP but i don't have the key"
                return 1
        fi
fi
x=0
echo -n "------------- Associating with $AP"
while [ $x -lt 10 ];do
        A=`iwconfig $i | grep -i 'Not-Associated'|wc -c`
        if [ ${A} -eq 0 ];then
                echo "";echo "------------- Associated to $AP !!!"
                dhclient -q -r $i
                dhclient $i
                exit 0
        else
                echo -n "."
        fi
        sleep 1
        x=`echo "$x + 1" | bc`

done
echo "";echo "------------- ERROR: Could not associate"
}

#-------------------------------------------------------------------------------------------------------------------
# Connect to any accesspoint we can sniff
#-------------------------------------------------------------------------------------------------------------------
auto () {
        cat /tmp/scan.$$ | awk -F':' '{ print $3 }' |while read ap;do
                echo "---------- trying to connect to $ap"
                conn $ap
        done
}


#-------------------------------------------------------------------------------------------------------------------
# Main
#-------------------------------------------------------------------------------------------------------------------
ifconfig -a | egrep -i 'mon|wlan' | awk '{ print $1 }' |while read i;do airmon-ng stop $i; done > /dev/null 2>&1
ifconfig $i down
ifconfig $i up
scanw $i > /tmp/scan.$$
cat /tmp/scan.$$
if [ $# -lt 1 ];then
        echo "-------- WARNING: no Accesspoint specified, will try to connect to the ones i see alive"
        auto
else
        conn
fi
rm /tmp/scan.$$

Posted by rdircio