<?php

if (isset ($_SESSION['started']) && isset ($_SESSION['logged_in']) && $_SESSION['logged_in'] == true) {
    $idle = time() - $_SESSION['LAST_ACTIVITY'];
    if ($idle > 6 * 60) {
        $_SESSION['logged_in'] = false;
        header(sprintf("Location: %s", $redirectback));
    }
}
else
    $_SESSION['started'] = time ();
$_SESSION['LAST_ACTIVITY'] = time ();