function get_client_ip() {
   static $ip = NULL; if ($ip !== NULL) return $ip; if (isset($_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     $ip = (false !== ip2long($ip)) ? $ip : '0.0.0.0'; return $ip; }