#!/usr/bin/awk -f
# Enumerate all usable addresses in an IPv4 subnet
#
# By Stefan Tomanek <stefan.tomanek@wertarbyte.de>
#
# Call like this: ipcalc 192.168.0.0/24 | ip-enumerate.awk

function addr(a) {
    return a[1]"."a[2]"."a[3]"."a[4];
}

function successor(a, n) {
    if (n>1 && (a[n] = (a[n]+1) % 255) == 0) {
        successor(a, n-1);
    }
}

$1 == "HostMin:" {MIN=$2}
$1 == "HostMax:" {MAX=$2}
END {
    split(MIN, a, ".");
    
    print addr(a);
    do {
        successor(a,4);
        print addr(a);
    } while (addr(a) != MAX);
}