#!/usr/bin/perl -w

# addrand.pl - a simple utility to return a range of ip addresses, sequentially
# or randomized, without any duplication.
#
# George Bakos alpinista@bigfoot.com
# - Sept 2002
#
# license terms - Use it, sell it, beat yourself over the head with it. I don't
# care. My Perl is ugly; feel free to take credit for it.
#
# On a linux 2.4.18 K6-1.4G box w/512MB RAM & 256M swap, this script was able to
# generate and randomize 98% of a /8 net block. I wouldn't recommend trying
# a range as large as that if you expect to run any fat X apps at the same time.

use Getopt::Std;
use Socket;

our ($opt_r, $opt_t) = (0,0);
getopts('rt:');

$randomize = $opt_r;
$addrspec = "$opt_t";

# expand any wildcards

$addrspec =~ s/\*/0-255/g;

# After converting asterisks, target spec can have address octets or octet 
# ranges, none greater than 255.

if ($addrspec !~ /\b[0-9]{1,3}(-[0-9]{1,3})?\.[0-9]{1,3}(-[0-9]{1,3})?\.[0-9]{1,3}(-[0-9]{1,3})?\.[0-9]{1,3}(-[0-9]{1,3})?\b/) { usage() };
@pieces = split /[\.-]/, $addrspec;
for $piece (@pieces) {
    if ($piece > 255) { usage() };
}

# Do we have any ranges specified? Look for a hyphen.

if ($addrspec =~ /-/) {
    @octets = split(/\./, $addrspec);
    my $num;

# Examine each octet specified for a hyphen. When we find one, it's time to 
# build a list from the range specified for that octet.

    foreach $octet (@octets) {
        $num++;
        my $octnum = "octet$num";
        if ($octet =~ /[0-9]{1,3}-[0-9{1,3}]/) {
            my (@range, $cnt);
            @range = split(/-/, $octet);
            for ($cnt = $range[0]; $cnt <= $range[1]; $cnt++) {
                push @$octnum, $cnt;
            }
        } else {
            push @$octnum, $octet;
        }
    }

# Build new array of addresses from the lists of individual octet values. We use
# inet_aton() to conserve precious RAM.

    @targets = ();
    foreach $octet1 (@octet1) {
        foreach $octet2 (@octet2) {
            foreach $octet3 (@octet3) {
                foreach $octet4 (@octet4) {
                    #print join(".", $octet1, $octet2, $octet3, $octet4), "\n";
                    push @targets, inet_aton(join(".", $octet1, $octet2, $octet3, $octet4));
                }
            }
        }
    }

# If there is only one address specified, that is the entire array

} else { 
    @targets = ($addrspec);
}

# don't try to randomize unless there is more than one element

if ($randomize && @targets > 1 ) {
    pullrand( \@targets );

} elsif (@targets > 1 ) {
        while ( $targets[0] ) {
                print STDOUT inet_ntoa(shift @targets), "\n";
    }

} else { 
    print STDOUT "$addrspec\n";
}

sub pullrand {
    my $array = shift;
    while ( @$array[0] ) {
        my $j = int rand ( @$array );
        @$array[0,$j] = @$array[$j,0];
        print STDOUT inet_ntoa(shift @$array), "\n";
    }
}

sub usage {
    print STDERR     "Usage: $0 [-r] -t <address w/ranges>\n";
    print STDERR    "\t example: $0 -r -t 10.0.4-5.1-254\n\n";
    exit
}