I'm trying to get logged in user id after if else statement but always return 0. When i put get_current_user_id() before it gives correct user id. How can I make it work in if statement?

<?php

function asd_endpt(){ 

//$user_id = get_current_user_id();
//echo $user_id; //<-- this returns user id


if (isset($_SERVER['HTTP_CF_CONNECTING_IP'])) { //Get Real IP
    $IP = $_SERVER['HTTP_CF_CONNECTING_IP'];
} else {
    $IP = $_SERVER['REMOTE_ADDR'];
}

if ($IP=="60.220.200.75" || $IP=="60.220.200.76") {
    $user_id = get_current_user_id();
    echo $user_id; //<-- this always return 0
}
add_shortcode('asd_endpt','asd_endpt');
?>