C Class IP Check

function get_bits($domain)
{
$domain = split('\.', gethostbyname($domain));
$domain = $domain[0]*256*256*256 + $domain[1]*256*256 + $domain[2]*256 + $domain[3];
return $domain;
}

function get_ip_class($ip)
{
if (($ip>>31) == 0) return ‘A’;
if (($ip>>30) == 2) return ‘B’;
if (($ip>>29) == -2) return ‘C’;
if (($ip>>28) == -2) return ‘D’;
if (($ip>>28) == -1) return ‘E’;
}
$domain1 = $_GET['domain1'];
$domain2 = $_GET['domain2'];
if($domain1 and $domain2) {
$d1 = parse_url($domain1, PHP_URL_HOST);
$d2 = parse_url($domain2, PHP_URL_HOST);
$d1 = $d1 ? $d1 : $domain1;
$d2 = $d2 ? $d2 : $domain2;

$ip1 = get_bits($d1);
$ip2 = get_bits($d2);
$c1 = get_ip_class($ip1);
$c2 = get_ip_class($ip2);
$last8 = 0×000000ff;
if (($c1 == ‘C’) && ($c2 == ‘C’) && (($last8 & $ip1) == ($last8 & $ip2))) {
$r = ‘ ‘;
$r2 = ‘ (‘.join(’.', array_slice(split(’\.’, gethostbyname($d1)), 0, -1)).’.*)’;
} else {
$r = ‘ NOT ‘;
$r2 = ”;
}
echo ‘Class C information
‘;
echo ‘The 2 domains are ‘.$r.’ hosted on the same Class C IP range.’.$r2.’
‘;
echo $d1.’ is hosted on Class ‘.$c1.’ IP ‘.gethostbyname($d1).’
‘;
echo $d2.’ is hosted on Class ‘.$c2.’ IP ‘.gethostbyname($d2).’
‘;
}
?>