<?php
  /**
   * Original code from svn://hostip.info/hostip/api/trunk. Optimized & enhanced by Quang Pham @ Saoma, 06.01.07.
   */   
  function isPrivateIP($ip) {
    list($a, $b, $c, $d) = sscanf($ip, "%d.%d.%d.%d");
    return  $a === null || $b === null || $c === null || $d === null ||
            $a == 10    ||
            $a == 239   ||
            $a == 0     ||
            $a == 127   ||
           ($a == 172 && $b >= 16 && $b <= 31) ||
           ($a == 192 && $b == 168);
  }   
   
  function getIP() {
    $default = false;
   
    if (isset($_SERVER)) {
      $default_ip = $_SERVER["REMOTE_ADDR"];     
      $xforwarded_ip = $_SERVER["HTTP_X_FORWARDED_FOR"];
      $client_ip = $_SERVER["HTTP_CLIENT_IP"];   
    } else {
      $default_ip = getenv('REMOTE_ADDR');
      $xforwarded_ip = getenv('HTTP_X_FORWARDED_FOR');
      $client_ip = getenv('HTTP_CLIENT_IP');
    }
   
    if ($xforwarded_ip != "") {
      $result = $xforwarded_ip;
    } else if ($client_ip != "") {
      $result = $client_ip;
    } else {
      $default = true;
    }
   
    if (!$default) { // additional check for private ip numbers
      $default = isPrivateIP($result);
    }
   
    if ($default) {
      $result = $default_ip;
    }
   
    return $result;
  }
 
  function showUSContent() {
    // show US content here, for ex. Yahoo! ads 
  }
 
  function showInternationalContent() {
    // show international content here, for ex. Google ads
  }
 
  function showGeoTargetContent() {
    // make a valid request to the hostip.info API 
    $url = "http://api.hostip.info/country.php?ip=".getIP();
 
    // fetch with curl
    $ch = curl_init();
 
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_HEADER, 0);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    $country = curl_exec($ch);
 
    curl_close ($ch);
 
    // display according geotarget
    if ($country == "US") {
      showUSContent();
    } else {   
      showInternationalContent();
    }
  } 

  showGeoTargetContent();
?>