PHPでIPアドレス範囲を制限する方法

function get_real_ipaddress() {
 if (!empty($_SERVER['HTTP_CLIENT_IP'])) {
  return $_SERVER['HTTP_CLIENT_IP'];
 } elseif (!empty($_SERVER['HTTP_X_FORWARDED_FOR'])) {
  return $_SERVER['HTTP_X_FORWARDED_FOR'];
 }
 return $_SERVER['REMOTE_ADDR'];
}
function in_ip_range($ip, $ip_one, $ip_two = false) {
 if(!$ip_two) {
  return $ip_one === $ip;
 }
 return ip2long($ip_one) * -1 >= ip2long($ip) * -1 && ip2long($ip_two) * -1 <= ip2long($ip) * -1;
}
function validate_ip() {
 $ip = explode(&#39;:&#39;, get_real_ipaddress());
 $ip = $ip[0];
 if(in_ip_range($ip, &#39;212.76.229.115&#39;, &#39;212.76.229.120&#39;)) {
  return true;
 } else if(in_ip_range($ip, &#39;194.78.4.66&#39;, &#39;194.78.4.79&#39;)) {
  return true;
 } else if(in_ip_range($ip, &#39;194.8.4.78&#39;, &#39;194.8.4.78&#39;)) {
  return true;
 } else if(in_ip_range($ip, &#39;0&#39;, &#39;1&#39;)) { // local
  return true;
 }
 header(&#39;Location: http://www.jb51.net&#39;);
}