获取用户ip地址

//获取用户ip地址
function get_ip()
{
    static $ip;
    if (isset($_SERVER)) {
        if (isset($_SERVER["HTTP_X_FORWARDED_FOR"])) {
            $ip = $_SERVER["HTTP_X_FORWARDED_FOR"];
        } else if (isset($_SERVER["HTTP_CLIENT_IP"])) {
            $ip = $_SERVER["HTTP_CLIENT_IP"];
        } else {
            $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 {
            $ip = getenv("REMOTE_ADDR");
        }
    }

    if (preg_match('/^(([1-9]?[0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5]).){3}([1-9]?[0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])$/', $ip)) {
        return $ip;
    } else {
        return '127.0.0.1';
    }
}