查询IP地址的PHP代码

function getip () {
  static $ip = '';
  $ip = $_SERVER ['REMOTE_ADDR'];
  if (isset ($_SERVER ['HTTP_CDN_SRC_IP'])) {
    $ip = $_SERVER ['HTTP_CDN_SRC_IP'];
  } elseif (isset ($_SERVER ['HTTP_CLIENT_IP']) && preg_match ('/^ ( [0-9] {1,3}\\.) {3} [0-9] {1,3}$/', $_SERVER ['HTTP_CLIENT_IP'])) {
    $ip = $_SERVER ['HTTP_CLIENT_IP'];
  } elseif (isset ($_SERVER ['HTTP_X_FORWARDED_FOR']) AND preg_match_all ('#\\d {1,3}\\.\\d {1,3}\\.\\d {1,3}\\.\\d {1,3}#s', $_SERVER ['HTTP_X_FORWARDED_FOR'], $matches)) {
    foreach ($matches [0] AS $xip) {
      if (!preg_match ('#^ (10|172\\.16|192\\.168)\\.#', $xip)) {
        $ip = $xip;
        break;
      }
    }
  }
  return $ip;
}