php check if IP is in given network range

ip_in_range.php

<?php


/**
* Check if a given ip is in a network.
*
* @see https://gist.github.com/ryanwinchester/578c5b50647df3541794
*
* @param  string $ip     IP to check in IPV4 format eg. 127.0.0.1
* @param  string $range  IP/CIDR netmask eg. 127.0.0.0/24, also 127.0.0.1 is accepted and /32 assumed
* @return bool           true if the ip is in this range / false if not.
*/
function ip_in_range($ip, $range)
{
    if (strpos($range, '/') == false) {
    	$range .= '/32';
    }

    // $range is in IP/CIDR format eg 127.0.0.1/24
    list($range, $netmask) = explode('/', $range, 2);

    $ip_decimal = ip2long($ip);
    $range_decimal = ip2long($range);
    $wildcard_decimal = pow(2, (32 - $netmask)) - 1;
    $netmask_decimal = ~ $wildcard_decimal;

    return (($ip_decimal & $netmask_decimal) == ($range_decimal & $netmask_decimal));
}