#!/bin/bash

# lan_ip_tester.sh
# Meryll Larkin September 13, 2014
# corrected December 21, 2018
# Put your local network designation in the LAN variable in this format:
# LAN='192.168.1.0/24-LAN1 10.0.0.0/28-LAN2'
# Each LAN written in slash subnet notation, followed by a dash and a label
# A space separated list.  
# The entire list enclosed by single quotes.

LAN='192.168.1.0/24-LAN1 10.0.0.0/28-LAN2'

ostype=`uname -o`
# Cygwin
# GNU/Linux   (ubuntu)

now=`date +%Y%m%d%H%M | tr -d '\r|\n'`

end='.txt'
ofile="ping_output_$now"
outfile="$ofile$end"

if [[ $ostype = Cygwin* ]]; then
    myping="ping -n 1"
else
    myping="ping -B -W 3 -t 1 -c 1"
fi

function error()  {
   echo $1
   echo "Exiting."
   exit 1
}

function get_avail_ips()  {
    case $subnet in
    8)
      num_ips="16777216"
      ;;
    9)
      num_ips="8388608"
      ;;
    10)
      num_ips="4194304"
      ;;
    11)
      num_ips="2097152"
      ;;
    12)
      num_ips="1048576"
      ;;
    13)
      num_ips="524288"
      ;;
    14)
      num_ips="262144"
      ;;
    15)
      num_ips="131072"
      ;;
    16)
      num_ips="65536"
      ;;
    17)
      num_ips="32768"
      ;;
    18)
      num_ips="16384"
      ;;
    19)
      num_ips="8192"
      ;;
    20)
      num_ips="4096"
      ;;
    21)
      num_ips="2048"
      ;;
    22)
      num_ips="1024"
      ;;
    23)
      num_ips="512"
      ;;
    24)
      num_ips="256"
      ;;
    25)
      num_ips="128"
      ;;
    26)
      num_ips="64"
      ;;
    27)
      num_ips="32"
      ;;
    28)
      num_ips="16"
      ;;
    29)
      num_ips="8"
      ;;
    30)
      num_ips="4"
      ;;
    31)
      num_ips="2"
      ;;
    32)
      num_ips="1"
      ;;
    esac
}

for lan in $LAN ;
  do
   subnote=`echo $lan | cut -d'.' -f4`
   # echo "LAN with subnotation = $lan"
   # echo "last octet and subnotation = $subnote"
   lastoct=`echo $subnote | cut -d'/' -f1`
   # test that starting ip address is a valid one
   if [ $lastoct -gt 256 ] ; then
       error "Invalid ip address $LAN $lastoct"
   fi
   firstoct=`echo $lan | cut -d'.' -f1`
   if [ $firstoct -gt 256 ] ; then
       error "Invalid ip address $LAN $firstoct"
   fi
   secondoct=`echo $lan | cut -d'.' -f2`
   if [ $secondoct -gt 256 ] ; then
       error "Invalid ip address $LAN $secondoct"
   fi
   thirdoct=`echo $lan | cut -d'.' -f3`
   if [ $thirdoct -gt 256 ] ; then
       error "Invalid ip address $LAN $thirdoct"
   fi
   subnetv=`echo $subnote | cut -d'/' -f2`
   # subnetv and subnet will be different if multiple LANs are supplied
   subnet=`echo $subnetv | cut -d'-' -f1`
   vnet=`echo $subnetv | cut -d'-' -f2`
   # echo "lastoct = $lastoct"
   # echo -n "subnet = $subnet "
   # echo -n "vnet = $vnet "
   # call subroutine to get the number of available IP addresses in each LAN
   get_avail_ips
   netoct1=`echo $lan | cut -d'.' -f4 --complement`
   echo "netoct1 = $netoct1"
   netoct=`echo "$netoct1" | sed 's/$/./'`
   # echo "netoct = $netoct"
   # echo "num_ips = $num_ips"
   # echo "netoct lastoct = $netoct$lastoct"


   for i in $(eval echo "{0..$num_ips}");
     do
      # echo "num_ips = $num_ips  i = $i"
      echo "pinging $netoct$lastoct"
      echo -n "$vnet $netoct$lastoct ">>$outfile
      # $myping $netoct$lastoct > /dev/null && echo "UP" >>$outfile || : & echo "DOWN" >>$outfile
      $myping $netoct$lastoct > /dev/null
      if [ $? -eq 0 ] ; then
          echo "UP" >>$outfile
      else
          echo "DOWN" >>$outfile
      fi
      ((lastoct = lastoct + 1))
      if [ $lastoct -eq 256 ] ; then
          ((lastoct = 0))
          ((thirdoct = thirdoct +1))
      fi
      if [ $thirdoct -eq 256 ] ; then
          ((thirdoct = 0))
          ((secondoct = secondoct +1))
      fi
      if [ $secondoct -eq 256 ] ; then
          ((secondoct = 0))
          ((firstoct = firstoct +1))
      fi
      if [ $firstoct -eq 256 ] ; then
          error "$netoct$lastoct plus one is not a valid ip address"
      fi
      netoct=${firstoct}.${secondoct}.${thirdoct}.
   done
done