获取客户端IP

/**
* 获取客户端IP地址
*
* @return string
*/
public static function getClientIp()
{
if (!empty($_SERVER["HTTP_CLIENT_IP"]))
return $_SERVER["HTTP_CLIENT_IP"];

if (!empty($_SERVER["HTTP_X_FORWARDED_FOR"]))
$proxy_ip = $_SERVER["HTTP_X_FORWARDED_FOR"];
elseif (($tmp_ip = getenv("HTTP_X_FORWARDED_FOR")))
$proxy_ip = $tmp_ip;
else
$proxy_ip = '';

if ('' !== $proxy_ip)
{
if (false === strpos($proxy_ip, ','))
return $proxy_ip;

foreach (explode(',', $proxy_ip) as $curr_ip)
{// 处理可能有多级代理的情况
if (false === stripos($curr_ip, 'unknown'))
$curr_ip = ltrim($curr_ip);
else
continue;

if (0 === strpos($curr_ip, '192.168.'))
continue;	// 内网IP
if (0 === strpos($curr_ip, '10.'))
continue;	// 内网IP
if (0 === strpos($curr_ip, '172.16.'))
continue;	// 内网IP

return $curr_ip;
}
}

if(!empty($_SERVER["REMOTE_ADDR"]))
return $_SERVER["REMOTE_ADDR"];
elseif(($retvl = getenv("HTTP_CLIENT_IP")))
return $retvl;
elseif(($retvl = getenv("REMOTE_ADDR")))
return $retvl;
else
return '0.0.0.0';
}