php获取用户IPv4或IPv6地址的代码

<?php
function getIP() /*获取客户端IP*/
{
if (@$_SERVER["HTTP_X_FORWARDED_FOR"])
$ip = $_SERVER["HTTP_X_FORWARDED_FOR"];
else if (@$_SERVER["HTTP_CLIENT_IP"])
$ip = $_SERVER["HTTP_CLIENT_IP"];
else if (@$_SERVER["REMOTE_ADDR"])
$ip = $_SERVER["REMOTE_ADDR"];
else if (@getenv("HTTP_X_FORWARDED_FOR"))
$ip = getenv("HTTP_X_FORWARDED_FOR");
else if (@getenv("HTTP_CLIENT_IP"))
$ip = getenv("HTTP_CLIENT_IP");
else if (@getenv("REMOTE_ADDR"))
$ip = getenv("REMOTE_ADDR");
else
$ip = "0.0.0.0";
return $ip;
}
?>