Emlog加cdn获取不到真实IP的解决办法

/**
 * 获取用户ip地址
 */
function getIp() {
	$ip = isset($_SERVER['REMOTE_ADDR']) ? $_SERVER['REMOTE_ADDR'] : '';
	if(isset($_SERVER['HTTP_X_FORWARDED_FOR'])){
		$list = explode(',', $_SERVER['HTTP_X_FORWARDED_FOR']);
		$ip = $list[0];
	}
	if (!ip2long($ip)) {
		$ip = '';
	}
	return $ip;
}