php获取客户端ip

/**  
 \* 获取客户端IP地址  
  \* @param integer $type 返回类型 0 返回IP地址 1 返回IPV4地址数字  
  \* @return mixed  
 */function get_client_ip($type = 0) {  
 $type =  $type ? 1 : 0;  
 static $ip  = NULL;  
 if ($ip !== NULL) return $ip[$type];  
 if (isset($_SERVER['HTTP_X_FORWARDED_FOR'])) {  
 $arr    = explode(',', $_SERVER['HTTP_X_FORWARDED_FOR']);  
 $pos    = array_search('unknown',$arr);  
 if(false !== $pos) unset($arr[$pos]);  
 $ip = trim($arr[0]);  
 }elseif (isset($_SERVER['HTTP_CLIENT_IP'])) {  
 $ip = $_SERVER['HTTP_CLIENT_IP'];  
 }elseif (isset($_SERVER['REMOTE_ADDR'])) {  
 $ip = $_SERVER['REMOTE_ADDR'];  
 } // IP地址合法验证  
 $long = sprintf("%u",ip2long($ip));  
 $ip = $long ? array($ip, $long) : array('0.0.0.0', 0);  
 return $ip[$type];  
}