function enable_code($mac,$access_code,$code)
{

$host = 'localhost';
$database = 'xxxxx';
$user = 'xxxx';
$pass = 'xxxx';

$link = mysqli_connect($host,$user,$pass,$database);
if(!$link){die("Database connection failde: ".mysqli_error());}
$dbselect = mysqli_select_db($link,$database);
if(!$dbselect){die("Database selection failed: ".mysqli_error($link));};

if ($access_code == $code)
{

    shell_exec("iptables -t mangle -I internet 1 -m mac --mac-source ".$mac." -j ACCEPT");


    mysqli_query($link,"UPDATE dataconnection SET enable = 1 WHERE mac = '$mac'");
    sleep(1);
    header("location:http://".$_GET['add']);
    exit;

}