findBox

#!/bin/bash
#
# findBox
#
# (c) Miguel Leitao, 2016
# Part of meoRemote: https://github.com/miguelleitao/meoRemote
#
# Scans network for available meoBoxes.
#
# Usage: ./findBox [-q] [-c] [NetMaskLenLimit [NetAddr]]
#     NetAddr defaults to addresses from all available net interfaces.
#     NetMaskLenLimit defaults to 24. Use 28 for a norrow (faster) search.
#     -q: quiet mode (no header)
#     -d: debug mode
#     -s: single mode. Only show first found box.
#     -c: config file mode. Use ./findBox -c >appname.conf
#
debug=0
nmap_exe="nmap"
nmap_cmd="$nmap_exe -n -Pn -p T:8082 --max-hostgroup 64 --open -oG -"
if ! command -v $nmap_exe &> /dev/null
then
   echo "Error: $nmap_exe could not be found."
   exit
fi
mask2cdr ()
{
   local x=${1##*255.}
   set -- 0^^^128^192^224^240^248^252^254^ $(( (${#1} - ${#x})*2 )) ${x%%.*}
   x=${1%%$3*}
   echo $(( $2 + (${#x}/4) ))
}

cdr2mask ()
{
   set -- $(( 5 - ($1 / 8) )) 255 255 255 255 $(( (255 << (8 - ($1 % 8))) & 255 )) 0 0 0
   [ $1 -gt 1 ] && shift $1 || shift
   echo ${1-0}.${2-0}.${3-0}.${4-0}
}

network_addr()
{
  # Calculate network address from address and prefix len
  # Usage: naddr = `network_mask ip_addr mask_len` 
  local nmask=`cdr2mask $2`
  local ia1; local ia2; local ia3; local ia4 
  IFS=. read -r ia1 ia2 ia3 ia4 <<< "$1"
  IFS=. read -r im1 im2 im3 im4 <<< "$nmask"
  local naddr="$((ia1 & im1)).$((ia2 & im2)).$((ia3 & im3)).$((ia4 & im4))"
  echo $naddr
}

masklen=24
if [ "$1" == "-q" ]; then
    quiet=1
    shift
fi
if [ "$1" == "-c" ]; then
    quiet=1
    conf=1
	#" |awk -c '{print \"box \" $5}"
    shift
fi
if [ "$1" == "-d" ]; then
    debug=1
    shift
fi
if [ "$1" == "-s" ]; then
    single=1
    shift
fi
[ "$1" != "" ] && masklen=$1
[ "$quiet" != "1" ] && echo "# meoBoxes found:"
addrs=`ifconfig | grep  -e 'inet .*' |grep -v 127.0.0.1 |cut -f2 -dt |cut -d' ' -f2`
[ "$2" != "" ] && addrs=$2
#echo "addrs: " $addrs
for i in $addrs; do
    [ "$i" = "192.168.122.1" ] && continue
    [ "$debug" = 1 ] && echo "local address: "$i
    nmask=`ifconfig |grep inet |grep $i |cut -f3 -dt |cut -f2 -dk |cut -d' ' -f2`
    [ "$debug" = 1 ] && echo "netmask: "$nmask
    min_cidr=`mask2cdr $nmask`
    [ "$debug" = 1 ] && echo "min_cidr: "$min_cidr
    cidr=$(( $masklen > $min_cidr ? $masklen : $min_cidr ))
    [ "$debug" = 1 ] && echo "cidr: "$cidr 
    if [ "$single" = 1 ]; then
	excludes=$i
        for scidr in `seq 31 -1 $cidr`; do
	    naddr=`network_addr $i $scidr`
            [ $debug = 1 ] && echo "netaddr: "$naddr
            cmd="$nmap_cmd --exclude $excludes $naddr/$scidr"
            [ "$debug" = 1 ] && echo "cmd: "$cmd
            if [ "$conf" != "1" ]; then
	        result=`$cmd |grep open/tcp | cut -f2 -d' '`
            else
	        result=`$cmd |grep open/tcp | awk -c '{print "box " $2}'`
            fi
	    size=${#result}
	    if [ "$size" -gt 10 ]; then
	 	echo $result
		exit;
	    fi
	    excludes="$naddr/$scidr"
	done
    else
        naddr=`network_addr $i $cidr`
        [ $debug = 1 ] && echo "netaddr: "$naddr
        cmd="$nmap_cmd --exclude $i $naddr/$cidr"
        [ "$debug" = 1 ] && echo "cmd: "$cmd
        if [ "$conf" != "1" ]; then
	    $cmd |grep open/tcp | cut -f2 -d' '
        else
	    $cmd |grep open/tcp | awk -c '{print "box " $2}'
        fi
    fi
done