[+] Check if the request is from CloudFlare

<?php
/**
+ Info: This script should help you out to check if the request is from CloudFlare and not directly though a ip address.
**/

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

# [+] IP Ranges - 01.11.2016 / Url: https://www.cloudflare.com/ips-v4
function _cloudflare_CheckIP($ip) {
    $cf_ips = array(
        '103.21.244.0/22',
        '103.22.200.0/22',
        '103.31.4.0/22',
        '104.16.0.0/12',
        '108.162.192.0/18',
        '131.0.72.0/22',
        '141.101.64.0/18',
        '162.158.0.0/15',
        '172.64.0.0/13',
        '173.245.48.0/20',
        '188.114.96.0/20',
        '190.93.240.0/20',
        '197.234.240.0/22',
        '198.41.128.0/17',
        '199.27.128.0/21'
      );

    $is_cf_ip = false;
    foreach ($cf_ips as $cf_ip) {
        if (ip_in_range($ip, $cf_ip)) {
            $is_cf_ip = true;
            break;
        }
    } return $is_cf_ip;
}

function _cloudflare_Requests_Check() {
    $flag = true;
    if(!isset($_SERVER['HTTP_CF_CONNECTING_IP']))   $flag = false;
    if(!isset($_SERVER['HTTP_CF_IPCOUNTRY']))       $flag = false;
    if(!isset($_SERVER['HTTP_CF_RAY']))             $flag = false;
    if(!isset($_SERVER['HTTP_CF_VISITOR']))         $flag = false;
    return $flag;
}

function isCloudflare() {
    $ipCheck        = _cloudflare_CheckIP($_SERVER['REMOTE_ADDR']);
    $requestCheck   = _cloudflare_Requests_Check();
    return ($ipCheck && $requestCheck);
}

# [+] Use when handling ip's
function getRequestIP() {
    $check = isCloudflare();
    if($check) {
        return $_SERVER['HTTP_CF_CONNECTING_IP'];
    } else {
        return $_SERVER['REMOTE_ADDR'];
    }
}

# [+] To use the script it's quite simple
$ip = getRequestIP();
$cf = isCloudflare();

if($cf) echo "CloudFlare Detected<br/>";
else    echo "Not CloudFlare";

echo "Your actual ip address is: ".$ip;
?>