codice:
//Enable debugging?
//This allows anyone to see the entire peer database by appending ?debug to the announce URL
define('__DEBUGGING_ON', false);
//What version are we at?
define('__VERSION', 1.3);
//How often should clients pull server for new clients? (Seconds)
define('__INTERVAL', 1800);
//What's the minimum interval a client may pull the server? (Seconds)
//Some bittorrent clients does not obey this
define('__INTERVAL_MIN', 300);
//How long should we wait for a client to re-announce after the last
//announce expires? (Seconds)
define('__CLIENT_TIMEOUT', 60);
//Skip sending the peer id if client does not want it?
//Hint: Should be set to true
define('__NO_PEER_ID', true);
//Should seeders not see each others?
//Hint: Should be set to true
define('__NO_SEED_P2P', true);
//Where should we save the peer database
//On Linux, you should use /dev/shm as it is very fast.
//On Windows, you will need to change this value to some
//other valid path such as C:/Peers.txt
define('__LOCATION_PEERS', 'C:/');
//Should we enable short announces?
//This allows NATed clients to get updates much faster, but it also
//takes more load on the server.
//(This is just an experimental feature which may be turned off)
define('__ENABLE_SHORT_ANNOUNCE', true);
//In case someone tries to access the tracker using a browser,
//redirect to this URL or file
define('__REDIR_BROWSER', './ui.php');
/***********************
** Configuration end **
***********************/
//Send response as text
header('Content-type: Text/Plain');
header('X-Tracker-Version: Bitstorm '.__VERSION.' by ck3r.org'); //Please give me some credit
//If you *really* dont want to, comment this line out
//Bencoding function, returns a bencoded dictionary
//You may go ahead and enter custom keys in the dictionary in
//this function if you'd like.
function track($list, $interval=60, $min_ival=0) {
if (is_string($list)) { //Did we get a string? Return an error to the client
return 'd14:failure reason'.strlen($list).':'.$list.'e';
}
$p = ''; //Peer directory
$c = $i = 0; //Complete and Incomplete clients
foreach($list as $d) { //Runs for each client
if ($d[7]) { //Are we seeding?
$c++; //Seeding, add to complete list
if (__NO_SEED_P2P && is_seed()) { //Seeds should not see each others
continue;
}
} else {
$i++; //Not seeding, add to incomplete list
}
//Do some bencoding
$pid = '';
if (!isset($_GET['no_peer_id']) && __NO_PEER_ID) { //Shall we include the peer id
$pid = '7:peer id'.strlen($d[1]).':'.$d[1];
}
$p .= 'd2:ip'.strlen($d[0]).':'.$d[0].$pid.'4:porti'.$d[2].'ee';
}
//Add some other paramters in the dictionary and merge with peer list
$r = 'd8:intervali'.$interval.'e12:min intervali'.$min_ival.'e8:completei'.$c.'e10:incompletei'.$i.'e5:peersl'.$p.'ee';
return $r;
}
//Find out if we are seeding or not. Assume not if unknown.
function is_seed() {
if (!isset($_GET['left'])) {
return false;
}
if ($_GET['left'] == 0) {
return true;
}
return false;
}
/*
* Yeah, this is the database engine. It's pretty bad, uses files to store peers.
* Should be easy to rewrite to use SQL instead.
*
* Yes, sometimes collisions may occur and screw the DB over. It might or might not
* recover by itself.
*/
//Save database to file
function db_save($data) {
$b = serialize($data);
$h = @fopen(__LOCATION_PEERS, 'w');
if (!$h) { return false; }
if (!@flock($h, LOCK_EX)) { return false; }
@fwrite($h, $b);
@fclose($h);
return true;
}
//Load database from file
function db_open() {
$p = '';
$m = '';
$h = @fopen(__LOCATION_PEERS, 'r');
if (!$h) { return false; }
if (!@flock($h, LOCK_EX)) { return false; }
while (!@feof($h)) {
$p .= @fread($h, 512);
}
@fclose($h);
return unserialize($p);
}
//Check if DB file exists, otherwise create it
function db_exists($create_empty=false) {
if (file_exists(__LOCATION_PEERS)) {
return true;
}
if ($create_empty) {
if (!db_save(array())) {
return false;
}
return true;
}
return false;
}
//Default announce time
$interval = __INTERVAL;
//Minimal announce time (does not apply to short announces)
$interval_min = __INTERVAL_MIN;
/*
* This is a pretty smart feature not present in other tracker software.
* If you expect to have many NATed clients, add short as a GET parameter,
* and clients will pull much more often.
*
* This can be done automatically, simply try to open a TCP connection to
* the client and assume it is NATed if not successful.
*/
if (isset($_GET['short']) && __ENABLE_SHORT_ANNOUNCE) {
$interval = 120;
$interval_min = 30;
}
//Did we get any parameters at all?
//Client is probably a web browser, do a redirect
if (empty($_GET)) {
header('Location: '.__REDIR_BROWSER);
die();
}
//Create database if it does not exist
db_exists(true) or die(track('Unable to create database'));
$d = db_open();
//Do we want to debug? (Should not be used by default)
if (isset($_GET['debug']) && __DEBUGGING_ON) {
echo 'Connected peers:'.count($d)."\n\n";
print_r($d);
die();
}
//Did we get a failure from the database?
if ($d === false) {
die(track('Database failure'));
}
//Do some input validation
function valdata($g, $must_be_20_chars=false) {
if (!isset($_GET[$g])) {
die(track('Missing one or more arguments'));
}
if (!is_string($_GET[$g])) {
die(track('Invalid types on one or more arguments'));
}
if ($must_be_20_chars && strlen($_GET[$g]) != 20) {
die(track('Invalid length on '.$g.' argument'));
}
if (strlen($_GET[$g]) > 128) { //128 chars should really be enough
die(track('Argument '.$g.' is too large to handle'));
}
}
//Inputs that are needed, do not continue without these
valdata('peer_id', true);
valdata('port');
valdata('info_hash', true);
//Use the tracker key extension. Makes it much harder to steal a session.
if (!isset($_GET['key'])) {
$_GET['key'] = '';
}
valdata('key');
//Do we have a valid client port?
if (!ctype_digit($_GET['port']) || $_GET['port'] < 1 || $_GET['port'] > 65535) {
die(track('Invalid client port'));
}
//Array key, unique for each client and torrent
$sum = sha1($_GET['peer_id'].$_GET['info_hash']);
//Make sure we've got a user agent to avoid errors
//Used for debugging
if (!isset($_SERVER['HTTP_USER_AGENT'])) {
$_SERVER['HTTP_USER_AGENT'] = ''; //Must always be set
}
//When should we remove the client?
$expire = time()+$interval;
//Have this client registered itself before? Check that it uses the same key
if (isset($d[$sum])) {
if ($d[$sum][6] !== $_GET['key']) {
sleep(3); //Anti brute force
die(track('Access denied, authentication failed'));
}
}
//Add/update the client in our global list of clients, with some information
$d[$sum] = array($_SERVER['REMOTE_ADDR'], $_GET['peer_id'], $_GET['port'], $expire, $_GET['info_hash'], $_SERVER['HTTP_USER_AGENT'], $_GET['key'], is_seed());
//No point in saving the user agent, unless we are debugging
if (!__DEBUGGING_ON) {
unset($d[$sum][5]);
} elseif (!empty($_GET)) { //We are debugging, add GET parameters to database
$d[$sum]['get_parm'] = $_GET;
}
//Did the client stop the torrent?
//We dont care about other events
if (isset($_GET['event']) && $_GET['event'] === 'stopped') {
unset($d[$sum]);
db_save($d);
die(track(array())); //The RFC says its OK to return whatever we want when the client stops downloading,
//however, some clients will complain about the tracker not working, hence we return
//an empty bencoded peer list
}
//Check if any client timed out
foreach($d as $k => $data) {
if (time() > $data[3]+__CLIENT_TIMEOUT) { //Give the client some extra time before timeout
unset($d[$k]); //Client has gone away, remove it
}
}
//Save the client list
db_save($d);
//Compare info_hash to the rest of our clients and remove anyone who does not have the correct torrent
foreach($d as $id => $info) {
if ($info[4] !== $_GET['info_hash']) {
unset($d[$id]);
}
}
//Remove self from list, no point in having ourselfes in the client dictionary
unset($d[$sum]);
//Add a few more seconds on the timeout to balance the load
$interval += rand(0, 10);
//Bencode the dictionary and send it back
die(track($d, $interval, $interval_min));
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