Custom IP address filtering for Magento Maintenance mode

Question

I'm currently using some custom code to filter out IP addresses on a Magento store so I can access it whilst in development (maintenance mode).

My current code works fine except it's only for singular IP addresses added to an array.

How would I be best altering this to include cidr format addresses?

My current code is as follows:

    $ip = $_SERVER['REMOTE_ADDR'];
$allowed = array('81.155.118.210','86.136.148.200'); // these are the IP's that are allowed to view the site.

and then further down

    if (file_exists($maintenanceFile) && !in_array($ip, $allowed)) {
    include_once dirname(__FILE__) . '/errors/503.php';
    exit;
}

I would like to be able to use IP addresses such as 195.170.169.0/255 so that I don't have to add them all in singular format however I'm unsure on the best way to add cidr style IP addresses to the array?

Can someone please help?

Answer 1

You can use the following method I found on the PHP.net website:

  function ipCIDRCheck ($IP, $CIDR) {
    list ($net, $mask) = split ("/", $CIDR);

    $ip_net = ip2long ($net);
    $ip_mask = ~((1 << (32 - $mask)) - 1);

    $ip_ip = ip2long ($IP);

    $ip_ip_net = $ip_ip & $ip_mask;

    return ($ip_ip_net == $ip_net);
  }

And then do:

$ip = $_SERVER['REMOTE_ADDR'];
$allowed = "195.170.169.0/255";
if (file_exists($maintenanceFile) && !ipCIDRCheck($ip, $allowed)) {
    include_once dirname(__FILE__) . '/errors/503.php';
    exit;
}

Edit:

if you need this to work for both your array and your CIDR you can do:

$ip = $_SERVER['REMOTE_ADDR'];
$allowed = array('81.155.118.210','86.136.148.200');
$cidr = "195.170.169.0/255";
if (file_exists($maintenanceFile) && !in_array($ip, $allowed) && !ipCIDRCheck($ip, $cidr)) {
    include_once dirname(__FILE__) . '/errors/503.php';
    exit;
}