#!/bin/sh

device=$1
keys=$3
activekey=2
intervall=`echo $2 | sed 's/[rR]//'`

if [ "$intervall" = "$2" ]
then
  random=
else
  random=1
fi
  

: ${intervall:=15}
[ $intervall -lt 1 ] && intervall=1

delay=$intervall

if [ -z "`iwconfig \"$device\" 2>/dev/null`" ]
then
  exit
fi

while [ 1 ]
do
  if [ "$random" ]
  then
    rand=`b2d </dev/urandom`
    delay=`expr $intervall / 2 + $rand % $intervall`
    
    rand=`b2d </dev/urandom`
    activekey=`expr $rand % $keys + 1`
  else
    activekey=`expr $activekey + 1`
    if [ $activekey -gt $keys ]
    then
      activekey=1
    fi
  fi

  iwconfig $device key [$activekey] >/dev/null

  sleep $delay
done