[Za-pm] FYI: IP to Integer and back

[Nico Coetzee]

I don't know if some of you work a lot with IP addresses, but it's easier to 
manipulate large amounts of addresses if you work with the Integer value of 
an IP. Here is a short script to illustrate the use:

<CODE>
#!/usr/bin/perl

$ipnumber = ip2ipn( "192.168.0.1" );
if ( $ipnumber ) {
	print "IPN : $ipnumber\n";
	$ip = ipn2ip( $ipnumber );
	if ( $ip ) {
		print "IP  : $ip\n";
	}
}

sub ip2ipn {
	# this sub will change an IP to the Integer value
	if ( $_[0] =~ /^\d+\.\d+\.\d+\.\d+/ ) {
		$_[0] =~ /^(\d+)\.(\d+)\.(\d+)\.(\d+)$/;
		my $num = (16777216*$1)+(65536*$2)+(256*$3)+$4;
		return $num;
	} else {
		return 0;
	}
}

sub ipn2ip {
	# this sub returns the IP address from an Integer
	# logical range is from 0.0.0.1 to 255.255.255.255
	if ( ( $_[0] > 0 ) && ( $_[0] < 4294967295 ) ) {
		my $ipn = $_[0];
		my $w=($ipn/16777216)%256;
		my $x=($ipn/65536)%256;
		my $y=($ipn/256)%256;
		my $z=$ipn%256;
		my $ipn = $w . "." . $x . "." . $y . "." . $z;
		return $ipn;
	} else {
		return 0;
	}
}
</CODE>

I assume there are other modules to handle this - but then, this is a learning 
experience :) BTW - let's see how we can improve this - making the subs less 
lines etc.

Let me know what you people think...

Cheers

-- 
Nico Coetzee

http://www.itfirms.co.za/
http://za.pm.org/
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