#!/usr/bin/perl -Twl
use strict;
use Net::IP ();
use Net::Netmask ();
use Data::Dumper;
use constant DEBUG => 0;
delete $ENV{$_} for qw(PATH CDPATH ENV);

my $B = {};

*OVERLAP = sub {
	my ($b1, $b2) = @_;
	@ARGV
	?
		_taz_overlap(
				$B->{$b1}{net},
				$B->{$b1}{mask},
				$B->{$b2}{net},
				$B->{$b2}{mask}
			)
	:
		_mituc_overlap(
				$B->{$b1}{inet},
				$B->{$b1}{ibcast},
				$B->{$b2}{inet},
				$B->{$b2}{ibcast}
			);
};

sub _taz_overlap {
	qx{./taz-overlap @_} =~ /overlap/
}

sub _mituc_overlap {
	my  ($netaddr1, $broadcast1, $netaddr2, $broadcast2) = @_;
	($netaddr1>$netaddr2 || $broadcast1>=$netaddr2)
	&&
    ($netaddr2<=$broadcast1 || $broadcast1<=$broadcast2);
};
                                        

# populate network blocks
while (<DATA>) {
	chomp;
	if (exists $B->{$_}) {
		warn "Duplicate block '$_'\n";
		next;
	}
	my $ip = Net::IP->new($_);
	unless ($ip) {
		warn "Invalid block '$_'\n";
		next;
	}
	$B->{$_} = {
			len => $ip->prefixlen,
			net => $ip->ip,
			bcast => $ip->last_ip,
			mask => $ip->mask,
			inet => $ip->intip->bstr,
			ibcast => Net::IP->new($ip->last_ip)->intip->bstr,
	};
}
print Dumper $B if DEBUG;

# store a sorted blocks list
my @blocks = sort { $B->{$a}{inet} <=> $B->{$b}{inet}
					or $B->{$a}{len} <=> $B->{$b}{len}
				} keys %$B;

# overlapping check up
foreach (0 .. $#blocks-1) {
	my $b1 = $blocks[$_];
	foreach my $b2 ((@blocks)[$_+1 .. $#blocks]) {
		if (OVERLAP($b1, $b2)) {
			warn "OVERLAP: $b1 vs. $b2\n";
			warn "  $B->{$b1}{net}-$B->{$b1}{bcast} vs. $B->{$b2}{net}-$B->{$b2}{bcast})\n" if DEBUG;
		} elsif (OVERLAP($b2, $b1)) {
			warn "OOPS! $b2 vs. $b1 seems to OVERLAP but $b1 vs. $b2 does NOT!\n";
			warn "  $B->{$b1}{net}-$B->{$b1}{bcast} vs. $B->{$b2}{net}-$B->{$b2}{bcast})\n" if DEBUG;
		}
	}
}

__DATA__
10.0.0.5/22
10.0.0.0/8
10.0.0.0/14
10.0.0.0/14
10.1.0.0/16
10.128.0.0/22
255.255.255.255
10.11.11.11
10.11.11.0/24