scannet.sh

#!/bin/bash

# Simple network scan based on ICMP echo requests. 
# Something for when arp scanning is not working.
# @author cab404

if [[ -z $2 ]]; then
        echo "specify mask and bit length like so: '192.168.1.0 24'"
        exit 0;
fi

c1=$(echo $1 | grep -Po '([0-9]{1,3})' | head -n1 | tail -1)
c2=$(echo $1 | grep -Po '([0-9]{1,3})' | head -n2 | tail -1)
c3=$(echo $1 | grep -Po '([0-9]{1,3})' | head -n3 | tail -1)
c4=$(echo $1 | grep -Po '([0-9]{1,3})' | head -n4 | tail -1)
BC=$2

let '
bitmask=c1<<24|c2<<16|c3<<8|c4,
host_count=(1<<(32-BC))
'

host=0; running=1;
while [[ $running == 1 ]]; do
        let '
                ip_bytes=bitmask^host,
                c1=(ip_bytes&(255<<24))>>24,
                c2=(ip_bytes&(255<<16))>>16,
                c3=(ip_bytes&(255<<8))>>8,
                c4=(ip_bytes&(255<<0))>>0,
                running=++host<host_count
        '
        ip=$c1.$c2.$c3.$c4;
        echo -ne "$ip: \t";
        ping -c 1 -w 1 $ip | grep "64 bytes" &
        pid=$!; sleep 0.01s; disown $pid; kill -9 $pid > /dev/null 2>&1;
        echo -ne "\r"
done

echo ''