php whitelist that supports cidr notation

cidr_whitelist.php

<?php
////判断IP是不是在白名单内的算法-PHP
////$_SERVER['REMOTE_ADDR'] = $_SERVER['argv'][1];
$ip="10.1.1.1";

$client = sprintf('%u', ip2long($ip));
$whitelist = array('127.0.0.0/10', '10.0.0.0/8', '192.168.1.0/24','60.207.94.32/27');
$whitelisted = false;

foreach ($whitelist as $range) {
    $ip = $range;
    $cidr = 32;
    if (strpos($range, '/')) 
        list($ip, $cidr) = explode('/', $range);
    $start = sprintf('%u', ip2long($ip));
    $hosts = pow(2, 32 - $cidr) -1;
    $end = $start + $hosts;
    if ($client >= $start && $client <= $end) {
        $whitelisted = true;
        break;
    }
}

echo ($whitelisted ? 'is' : "isn't") . " allowed\n";