Ok, the original function is this: 

function portal_mac_radius($clientmac,$clientip) {
	global $config, $cpzone;

	$radmac_secret = $config['captiveportal'][$cpzone]['radmac_secret'];

	/* authentication against the radius server */
	$username = mac_format($clientmac);
	$auth_list = radius($username,$radmac_secret,$clientip,$clientmac,"MACHINE LOGIN");
	
	if ($auth_list['auth_val'] == 2)
		return TRUE;
	
	if (!empty($auth_list['url_redirection'])) 
	   portal_reply_page($auth_list['url_redirection'], "redir");

	return FALSE; /* I think at this point the function will always return false, this line also is conditioned*/
	
    
}

I could condition her putting in braces, but wanted to respect the original structure slightly moved so only position

if (!empty($auth_list['url_redirection'])) {
	   portal_reply_page($auth_list['url_redirection'], "redir");
           return FALSE; }