<?php
/**************************************************
*  Created:  2010-06-08
*
*  获取客户端IP地址
*
*  @Xweibo (C)1996-2099 SINA Inc.
*  @Author xionghui <xionghui1@staff.sina.com.cn>
*
***************************************************/

/**
 * 获取客户端IP地址
 *
 * @return string
 */
function get_client_ip(){
   if (getenv("HTTP_CLIENT_IP") && strcasecmp(getenv("HTTP_CLIENT_IP"), "unknown"))
       $ip = getenv("HTTP_CLIENT_IP");
   else if (getenv("HTTP_X_FORWARDED_FOR") && strcasecmp(getenv("HTTP_X_FORWARDED_FOR"), "unknown"))
       $ip = getenv("HTTP_X_FORWARDED_FOR");
   else if (getenv("REMOTE_ADDR") && strcasecmp(getenv("REMOTE_ADDR"), "unknown"))
       $ip = getenv("REMOTE_ADDR");
   else if (isset($_SERVER['REMOTE_ADDR']) && $_SERVER['REMOTE_ADDR'] && strcasecmp($_SERVER['REMOTE_ADDR'], "unknown"))
       $ip = $_SERVER['REMOTE_ADDR'];
   else
       $ip = '0.0.0.0';
   return preg_match('/^((25[0-5]|2[0-4]\d|(1\d|[1-9])?\d)\.){3}(25[0-5]|2[0-4]\d|(1\d|[1-9])?\d)$/', $ip) ? $ip : '0.0.0.0';
}