<?

ob_start("ob_gzhandler");

require_once("include/bittorrent.php");
require_once("include/benc.php");

hit_start();

function hex2bin($hexdata) {

   for ($i=0;$i<strlen($hexdata);$i+=2) {
     $bindata.=chr(hexdec(substr($hexdata,$i,2)));
   }

   return $bindata;
}

function err($msg)
{
    benc_resp(array("failure reason" => array(type => "string", value => $msg)));
    hit_end();
    exit();
}

function benc_resp($d)
{
    benc_resp_raw(benc(array(type => "dictionary", value => $d)));
}

function benc_resp_raw($x)
{
    header("Content-Type: text/plain");
    header("Pragma: no-cache");
    print($x);
}

function check_ip_limit() {
    global $userid;

    // Check IP limit
    $res = mysql_query("SELECT DISTINCT(ip) AS ip FROM peers WHERE userid=$userid");
    $count = 0;
    $found = FALSE;
    while ($row = mysql_fetch_assoc($res)) {
        $count++;
        if ($row["ip"] == $ip) {
            $found = TRUE;
            break;
        }
    }

    if (!$found && $count >= $GLOBALS["MAX_PASSKEY_IPS"])
        err("Zu viele unterschiedliche IPs fuer diesen Benutzer (max ".$GLOBALS["MAX_PASSKEY_IPS"].")");
}

if (in_array($_SERVER["HTTP_USER_AGENT"], $GLOBALS["BAN_USERAGENTS"]))
    err("Du benutzt einen gebannten Client. Bitte lies die FAQ!");

$req = "info_hash:peer_id:!ip:port:uploaded:downloaded:left:!event";
if ($GLOBALS["CLIENT_AUTH"] == CLIENT_AUTH_PASSKEY) {
    if ($GLOBALS["PASSKEY_SOURCE"] == PASSKEY_USE_PARAM) {
        $req .= ":passkey";
        // Using announce.php?passkey={KEY} will lead to an incorrect parameter list,
        // so the first parameter appended by the client gets appended to the passkey parameter.
        // This match will extract the parameter to $_GET
        if (preg_match("/^([a-f0-9]{16})\\?(.*?)\\=(.*)$/is", $_GET["passkey"], $m)) {
            $_GET["passkey"] = $m[1];
            $_GET[$m[2]] = $m[3];
        }
    }
    if ($GLOBALS["PASSKEY_SOURCE"] == PASSKEY_USE_SUBDOMAIN) {
        preg_match("/^([a-f0-9]{16})\\./i", $_SERVER["HTTP_HOST"], $m);
        if (strlen($m[1])==16)
            $passkey = $m[1];
        else
            err("Fehlender Parameter fuer Announce: passkey");
    }
}

foreach (explode(":", $req) as $x)
{
    if ($x[0] == "!")
    {
        $x = substr($x, 1);
        $opt = 1;
    }
    else
        $opt = 0;
    if (!isset($_GET[$x]))
    {
        if (!$opt)
            err("Fehlender Parameter fuer Announce: $x");
        continue;
    }
    $GLOBALS[$x] = unesc($_GET[$x]);
}

foreach (array("info_hash","peer_id") as $x)
{
    if (strlen($GLOBALS[$x]) != 20)
        err("Ungueltiger Wert fuer $x (" . strlen($GLOBALS[$x]) . " - " . urlencode($GLOBALS[$x]) . ")");
}

foreach ($GLOBALS["BAN_PEERIDS"] as $banned_id)
{
    if (substr($GLOBALS["peer_id"],0,strlen($banned_id)) == $banned_id)
        err("Du benutzt einen gebannten Client. Bitte lies das FAQ!");
}

$ip = getip();
$origip = $ip;
$port = 0 + $port;
$origport = $port;
$downloaded = 0 + $downloaded;
$uploaded = 0 + $uploaded;
$left = 0 + $left;

$rsize = 50;
foreach(array("num want", "numwant", "num_want") as $k)
{
    if (isset($_GET[$k]))
    {
        $rsize = 0 + $_GET[$k];
        break;
    }
}

$agent = $_SERVER["HTTP_USER_AGENT"];

// Deny access made with a browser...
if (ereg("^Mozilla\\/", $agent) || ereg("^Opera\\/", $agent) || ereg("^Links ", $agent) || ereg("^Lynx\\/", $agent))
    err("Dieser Torrent ist dem Tracker nicht bekannt");

if (!$port || $port > 0xffff)
    err("Ungueltiges TCP-Port");

if (!isset($event))
    $event = "";

$seeder = ($left == 0) ? "yes" : "no";

dbconn(false);

hit_count();

$res = mysql_query("SELECT id, name, category, banned, activated, seeders + leechers AS numpeers, UNIX_TIMESTAMP(added) AS ts FROM torrents WHERE " . hash_where("info_hash", $info_hash));

$torrent = mysql_fetch_assoc($res);
if (!$torrent)
    err("Dieser Torrent ist dem Tracker nicht bekannt");

if ($torrent["activated"] != "yes")
    err("Dieser Torrent ist dem Tracker nicht bekannt");

$torrentid = $torrent["id"];

$fields = "seeder, peer_id, ip, port, uploaded, downloaded, userid";

$numpeers = $torrent["numpeers"];
$limit = "";
if ($numpeers > $rsize)
    $limit = "ORDER BY RAND() LIMIT $rsize";
$res = mysql_query("SELECT $fields FROM peers WHERE torrent = $torrentid AND connectable = 'yes' $limit");

$resp = "d" . benc_str("interval") . "i" . $GLOBALS["ANNOUNCE_INTERVAL"] . "e" . benc_str("peers") . "l";
unset($self);
while ($row = mysql_fetch_assoc($res))
{
    $row["peer_id"] = hash_pad($row["peer_id"]);

    if ($row["peer_id"] === $peer_id)
    {
        $userid = $row["userid"];
        $self = $row;
        continue;
    }

    $resp .= "d" .
        benc_str("ip") . benc_str($row["ip"]) .
        benc_str("peer id") . benc_str($row["peer_id"]) .
        benc_str("port") . "i" . $row["port"] . "e" .
        "e";
}

$resp .= "ee";

$selfwhere = "torrent = $torrentid AND " . hash_where("peer_id", $peer_id);

if (!isset($self))
{
    $res = mysql_query("SELECT $fields FROM peers WHERE $selfwhere");
    $row = mysql_fetch_assoc($res);
    if ($row)
    {
        $userid = $row["userid"];

        $self = $row;
    }
}


//// Up/down stats ////////////////////////////////////////////////////////////

if (!isset($self))
{
    if ($GLOBALS["CLIENT_AUTH"] == CLIENT_AUTH_PASSKEY) {
        $rz = mysql_query("SELECT id, uploaded, downloaded, class, tlimitseeds, tlimitleeches, tlimitall FROM users WHERE passkey=".sqlesc(hex2bin($passkey))." AND enabled = 'yes' ORDER BY last_access DESC LIMIT 1") or err("Tracker error 2");
        if ($MEMBERSONLY && mysql_num_rows($rz) == 0)
            err("Ungueltiger PassKey. Lies das FAQ!");
    } else {
        $rz = mysql_query("SELECT id, uploaded, downloaded, class, tlimitseeds, tlimitleeches, tlimitall FROM users WHERE ip=".sqlesc($ip)." AND enabled = 'yes' ORDER BY last_access DESC LIMIT 1") or err("Tracker error 2");
        if ($MEMBERSONLY && mysql_num_rows($rz) == 0)
            err("Unbekannte IP. Lies das FAQ!");
    }

    $az = mysql_fetch_assoc($rz);
    $userid = $az["id"];

    // Wartezeit prüfen
    $wait = get_wait_time($az["id"], $torrentid, FALSE, $left);
    if (($left > 0 || !$GLOBALS["ONLY_LEECHERS_WAIT"]) && $wait)
        err("Wartezeit (noch " . ($wait) . "h) - Bitte lies das FAQ!");

    // Torrent-Limit prüfen
    // $az["tlimitall"] < 0 entspricht unlimitiert!
    if ($az["tlimitall"] >= 0) {
        $arr = mysql_fetch_assoc(mysql_query("SELECT COUNT(*) AS cnt FROM peers WHERE userid=$userid"));
        $numtorrents = $arr["cnt"];
        $arr = mysql_fetch_assoc(mysql_query("SELECT COUNT(*) AS cnt FROM peers WHERE userid=$userid AND seeder='yes'"));
        $seeds = $arr["cnt"];
        $leeches = $numtorrents - $seeds;
        $limit = get_torrent_limits($az);

        if (   ($limit["total"] > 0)
            &&(($numtorrents >= $limit["total"])
            || ($left == 0 && $seeds >= $limit["seeds"])
            || ($left > 0 && $leeches >= $limit["leeches"])))
                err("Maximales Torrent-Limit erreicht ($limit[seeds] Seeds, $limit[leeches] Leeches, $limit[total] Gesamt)");

    }

    check_ip_limit();

    // Create traffic log entry if not existent
    $res = mysql_query("SELECT * FROM `traffic` WHERE `userid`=$userid AND `torrentid`=$torrentid");
    if (@mysql_num_rows($res) == 0)
        mysql_query("INSERT INTO `traffic` (`userid`,`torrentid`) VALUES ($userid, $torrentid)");
}
else
{
    // We won't check the IP again, since this would disrupt a user's download if he
    // uses another IP to continue browsing on the tracker.
    if ($GLOBALS["CLIENT_AUTH"] == CLIENT_AUTH_PASSKEY) {
        $res = mysql_query("SELECT passkey,id FROM users WHERE id=$userid AND enabled = 'yes'");
        $pkrow = mysql_fetch_assoc($res);
        $passkey = hex2bin($passkey);
        if ($passkey != $pkrow["passkey"])
            err("Ungueltiger PassKey. Lies das FAQ!");

        check_ip_limit();
    }

    $upthis = max(0, $uploaded - $self["uploaded"]);
    $downthis = max(0, $downloaded - $self["downloaded"]);

    $arr = mysql_fetch_assoc(mysql_query("SELECT UNIX_TIMESTAMP(last_action) AS lastaction FROM peers WHERE $selfwhere"));
    $interval = time() - $arr["lastaction"];

    if ($interval == 0) $interval = 1;

    // If speed is higher than 4 MB/sec, the user is apparently cheating.
    // Frustrate him by adding his desired upload to his download ^^
    if (($upthis / $interval) > $GLOBALS["RATIOFAKER_THRESH"]) {
        // Write mod comment
        write_modcomment($userid, 0, "announce.php: Ratiofaker-Tool verwendet: ".mksize($upthis)." Upload, Fake Rate: ".mksize($upthis / $interval)."/sek");

        // Add upload as download and zero out upload.
        $downthis += $upthis;
        $upthis = 0;
    }

    if ($upthis > 0 || $downthis > 0) {
        // Update traffic for current torrent
        if ($self["seeder"] == "yes")
            mysql_query("UPDATE `traffic` SET `downloaded`=`downloaded`+$downthis, `uploaded`=`uploaded`+$upthis, `uploadtime`=`uploadtime`+$interval WHERE `userid`=$userid AND `torrentid`=$torrentid");
        else
            mysql_query("UPDATE `traffic` SET `downloaded`=`downloaded`+$downthis, `uploaded`=`uploaded`+$upthis, `downloadtime`=`downloadtime`+$interval,`uploadtime`=`uploadtime`+$interval WHERE `userid`=$userid AND `torrentid`=$torrentid");
        mysql_query("UPDATE users SET uploaded = uploaded + $upthis, downloaded = downloaded + $downthis WHERE id=$userid") or err("Tracker error 3");
    }
}

// Bad user? If yes, we'll provide him with an invalid peer list :)
$acctdata = mysql_fetch_assoc(mysql_query("SELECT baduser FROM accounts WHERE userid=$userid"));
if ($acctdata["baduser"]==1) {
    $resarr = bdec($resp);
    for ($I=0; $I<count($resarr["value"]["peers"]["value"]); $I++) {
        $tmpip = $resarr["value"]["peers"]["value"][$I]["value"]["ip"]["value"];
        $resarr["value"]["peers"]["value"][$I]["value"]["port"]["value"] += mt_rand(100,250);

        $rndnum = mt_rand(1,254);
        $resarr["value"]["peers"]["value"][$I]["value"]["ip"]["value"] =
            preg_replace("/\\.(\\d{1,3})$/", ".$rndnum", $tmpip);

    }
    $resp = benc($resarr);

    $rndnum = mt_rand(1,254);
    $ip = preg_replace("/\\.(\\d{1,3})$/", ".$rndnum", $ip);
    $port += mt_rand(100,250);

}


///////////////////////////////////////////////////////////////////////////////

function portblacklisted($port)
{
    // direct connect
    if ($port >= 411 && $port <= 413) return true;

    // bittorrent
    if ($port >= 6881 && $port <= 6889) return true;

    // kazaa
    if ($port == 1214) return true;

    // gnutella
    if ($port >= 6346 && $port <= 6347) return true;

    // emule
    if ($port == 4662) return true;

    // winmx
    if ($port == 6699) return true;

    return false;
}

$updateset = array();

if ($event == "stopped")
{
    if (isset($self))
    {
        mysql_query("DELETE FROM peers WHERE $selfwhere");
        if (mysql_affected_rows())
        {
            if ($self["seeder"] == "yes")
                $updateset[] = "seeders = seeders - 1";
            else
                $updateset[] = "leechers = leechers - 1";
        }
    }
    mysql_query("INSERT INTO startstoplog (userid,event,`datetime`,torrent,ip,peerid,useragent) VALUES ($userid,'stop',NOW(),$torrentid,".sqlesc($_SERVER["REMOTE_ADDR"]).",".sqlesc($peer_id).",".sqlesc($agent).")");

    $announcedelay = @mysql_fetch_assoc(@mysql_query("SELECT * FROM `announcedelay` WHERE `peer_id`=".sqlesc($peer_id)));
    if (is_array($announcedelay)) {
        if ($announcedelay["first"] && $announcedelay["second"] && $announcedelay["quantity"]) {
            $duration1 = $announcedelay["second"]-$announcedelay["first"];
            $duration2 = time() - $announcedelay["second"];
            if ($duration1 < 310 && $duration2 < 10 && $uploaded - $announcedelay["quantity"] == 0) {
                write_modcomment($userid, 0, "announce.php: Evtl. Ratiomaker 0.5+ benutzt: ".mksize($uploaded)." Upload / ".mksize($downloaded)." Download, Fake Rate: ".mksize($uploaded / $duration1)."/sek, Delays: {$duration1}s / {$duration2}s");
            }
        }
    }

    $resp = benc_resp(array("failure reason" => array(type => "string", value => "Kein Fehler - Torrent gestoppt.")));
}
else
{
    if ($event == "completed") {
        $updateset[] = "times_completed = times_completed + 1";
        mysql_query("INSERT INTO completed (user_id, torrent_id, torrent_name, torrent_category, complete_time) VALUES ($userid, $torrentid, ".sqlesc($torrent["name"]).", ".$torrent["category"].", NOW())");
    }

    if (isset($self))
    {
        $announcedelay = @mysql_fetch_assoc(@mysql_query("SELECT * FROM `announcedelay` WHERE `peer_id`=".sqlesc($peer_id)));
        if (is_array($announcedelay)) {
            if ($announcedelay["second"] == 0)
                mysql_query("UPDATE `announcedelay` SET `second`=UNIX_TIMESTAMP(),`quantity`=$uploaded WHERE `peer_id`=".sqlesc($peer_id));
        }

        mysql_query("UPDATE peers SET uploaded = $uploaded, downloaded = $downloaded, to_go = $left, last_action = NOW(), seeder = '$seeder'"
            . ($seeder == "yes" && $self["seeder"] != $seeder ? ", finishedat = " . time() : "") . " WHERE $selfwhere");
        if (mysql_affected_rows() && $self["seeder"] != $seeder)
        {
            if ($seeder == "yes")
            {
                $updateset[] = "seeders = seeders + 1";
                $updateset[] = "leechers = leechers - 1";
            }
            else
            {
                $updateset[] = "seeders = seeders - 1";
                $updateset[] = "leechers = leechers + 1";
            }
        }
    }
    else
    {
        if (portblacklisted($origport))
            err("Der TCP-Port $origport ist nicht erlaubt.");
        else
        {
            $sockres = @fsockopen($origip, $origport, $errno, $errstr, 5);
            if (!$sockres)
                $connectable = "no";
            else
            {
                $connectable = "yes";
                @fclose($sockres);
            }
        }

        $ret = mysql_query("INSERT INTO peers (connectable, torrent, peer_id, ip, port, uploaded, downloaded, to_go, started, last_action, seeder, userid, agent, uploadoffset, downloadoffset) VALUES ('$connectable', $torrentid, " . sqlesc($peer_id) . ", " . sqlesc($ip) . ", $port, $uploaded, $downloaded, $left, NOW(), NOW(), '$seeder', $userid, " . sqlesc($agent) . ", $uploaded, $downloaded)");
        if ($ret)
        {
            if ($seeder == "yes")
                $updateset[] = "seeders = seeders + 1";
            else
                $updateset[] = "leechers = leechers + 1";
        }
        mysql_query("INSERT INTO startstoplog (userid,event,`datetime`,torrent,ip,peerid,useragent) VALUES ($userid,'start',NOW(),$torrentid,".sqlesc($_SERVER["REMOTE_ADDR"]).",".sqlesc($peer_id).",".sqlesc($agent).")");
        mysql_query("INSERT INTO announcedelay (peer_id, first) VALUES (".sqlesc($peer_id).", UNIX_TIMESTAMP())");
        mysql_query("DELETE FROM announcedelay WHERE `first`<UNIX_TIMESTAMP()-900");
    }
}

if ($seeder == "yes")
{
    if ($torrent["banned"] != "yes")
        $updateset[] = "visible = 'yes'";
    $updateset[] = "last_action = NOW()";
}

if (count($updateset))
    mysql_query("UPDATE torrents SET " . join(",", $updateset) . " WHERE id = $torrentid");

benc_resp_raw($resp);

hit_end();

?>