View difference between Paste ID: 7CMNPBT2 and D2mjg9Nb

 <?php
 
 /*
 
 Version history
 
 1     - Initial release.
 2     - Added option to use the official domain name instead of IPs and retry if
         a timeout occurs.
 2.1   - Added more master servers.
 2.1.1 - Fixed a bug, program didn't terminate if all master servers time out.
 2.1.2 - Removed a now redundant variable.
 2.2   - Seeding for long server lists.
       - Removed the domain name because it's often better to try different
         servers.
 2.2.1 - Bug fix: Timeout showed wrong master server IP.
       - Bug fix: Check whether the new seed starts with a duplicate or not.
       - Bug fix: Don't close socket twice.
 2.3   - Retry queries on timeout if the first query was successful.
 2.3.1 - Reading the whole address again if it starts with a zero.
       - Increased timeout to avoid a communication issue.
       - Removed maximum number of timeouts for testing.
 2.4   - Again using hl1master.steampowered.com because IPs change often.
       - Endless retries because this server often times out.
 2.5   - Trying following ports on timeout or if the response wasn't correct.
 2.5.3 - Cosmetic changes (defines, variable name).
 2.5.4 - Code optimisation.
 2.6   - Repeat until list isn't empty.
 */
 
 // Currently uses ports 27011-27013 and 27015.
 $master_servers = array("hl2master.steampowered.com");
 
 define("MIN_PORT", 27011); // Range of port numbers which the master servers
 define("MAX_PORT", 27015); // potentially use.
 define("FILTER", '\gamedir\tfc'); // game = Team Fortress Classic
 define("REGION", "\xFF"); // region = world
 define("TIMEOUT", 2.0); // 2s timeout
 
 function query_timeout($socket, $seed)
 {
    echo "Sending query to master server.\n";
    stream_set_timeout($socket, TIMEOUT);
    if (!fwrite($socket, "1".REGION."$seed\0".FILTER."\0"))
    {
       fclose($socket);
       exit("fwrite error\n");
    }
 
    echo "Reading response header.\n";
    stream_set_timeout($socket, TIMEOUT);
    $s = bin2hex(fread($socket, 6));
    $info = stream_get_meta_data($socket);
    if ($info['timed_out'])
       echo "Master server timed out.\n";
    else
    {
       if ($s !== "ffffffff660a")
       {
          fclose($socket);
          if ($s == "")
             echo "Expected ff ff ff ff 66 0a (hex) but got nothing.\n";
          else
             echo "Expected ff ff ff ff 66 0a (hex) but got $s.\n";
          return True;
       }
    }
    return $info['timed_out'];
 }
 
 // Connect to master server, return timeout info.
 // The socket is passed as reference and thus returned as well.
 
 function master_server_timeout(&$socket, $ip)
 {
    $port = MIN_PORT;
    do {
       echo "Connecting to master server \"$ip:$port\".\n";
       $socket = fsockopen("udp://$ip", $port, $errno, $errstr, TIMEOUT);
       if (!$socket) exit("Error $errno : $errstr \n");
       $timeout = query_timeout($socket, "0.0.0.0:0");
       $port = $port + 1;
    } while ($timeout && ($port <= MAX_PORT));
    return $timeout;
 }
 
 // Read list with server addresses (IP:port).
 
 function list_not_empty($socket)
 	{
 	$count = 0;
 	$old_a1 = 0; $old_a2 = 0; $old_a3 = 0; $old_a4 = 0; $old_a5 = 0;
 	$max_timeouts = 6;
 	do
 	{
 	   stream_set_timeout($socket, TIMEOUT);
 	   $a1 = ord(fread($socket,1));
 	   $info = stream_get_meta_data($socket);
 	   if ($info['timed_out'])
 	   {
 		  $seed = "$old_a1.$old_a2.$old_a3.$old_a4:$old_a5";
 		  echo "Seed: $seed\n";
 		  while (query_timeout($socket, $seed));
 		  stream_set_timeout($socket, TIMEOUT);
 		  $a1 = ord(fread($socket,1));
 		  $info = stream_get_meta_data($socket);
 		  if ($info['timed_out'])
 		  {
 			 echo "Timeout occured.\n";
 			 break;
 		  }
 		  $check_for_duplicate = 1;
 	   }
 	   else
 		  $check_for_duplicate = 0;
 
 	   // Let's always read the rest of the address (even if it starts with 0) in
 	   // order to empty the master server's write buffer. This may avoid subsequent
 	   // problems, but I'm paranoid here.
 	   $a2 = ord(fread($socket,1));
 	   $a3 = ord(fread($socket,1));
 	   $a4 = ord(fread($socket,1));
 	   $a5 = ord(fread($socket,1))*256 + ord(fread($socket,1));
 
 	   if ($a1 != 0)
 	   {
 		  if (($check_for_duplicate==0)||($a1!=$old_a1)||($a2!=$old_a2)||
 		  ($a3!=$old_a3)||($a4!=$old_a4)||($a5!=$old_a5))
 		  {
 			 $count++;
 			 echo "$count $a1.$a2.$a3.$a4:$a5\n";
 		  }
 		  $old_a1 = $a1; $old_a2 = $a2; $old_a3 = $a3; $old_a4 = $a4; $old_a5 = $a5;
 	   }
 	} while ($a1 != 0);
 	fclose($socket);
 
 	if ($count != 0) echo "Retrieved $count server addresses.\n";
 	return ($count != 0);
 }
 
 // Try all master servers until we find one that isn't timing out.
 
 foreach ($master_servers as $ip)
 	if ($timeout=master_server_timeout($socket, $ip))
 		fclose($socket);
 	else
 		if (list_not_empty($socket)) break;
 
 ?>