premiere-libtorrent/docs/udp_tracker_protocol.rst

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=========================================
Bittorrent udp-tracker protocol extension
=========================================
A tracker with the protocol "udp://" in its URI
is supposed to be contacted using this protocol.
This protocol is supported by
xbt-tracker_.
.. _xbt-tracker: http://xbtt.sourceforge.net
For additional information and descritptions of
the terminology used in this document, see
the `protocol specification`__
__ http://wiki.theory.org/index.php/BitTorrentSpecification
All values are sent in network byte order (big endian). The sizes
are specified with ANSI-C standard types.
If no response to a request is received within 15 seconds, resend
the request. If no reply has been received after 60 seconds, stop
retrying.
connecting
----------
Client sends packet:
+-------------+---------------------+----------------------------------------+
| size | name | description |
+=============+=====================+========================================+
| int64_t | connection_id | Not used, ignored by tracker. |
+-------------+---------------------+----------------------------------------+
| int32_t | action | 0 for a connection request |
+-------------+---------------------+----------------------------------------+
| int32_t | transaction_id | Randomized by client. |
+-------------+---------------------+----------------------------------------+
Server replies with packet:
+-------------+---------------------+----------------------------------------+
| size | name | description |
+=============+=====================+========================================+
| int32_t | action | Describes the type of packet, in this |
| | | case it should be 0, for connect. |
| | | If 3 (for error) see errors_. |
+-------------+---------------------+----------------------------------------+
| int32_t | transaction_id | Must match the transaction_id sent |
| | | from the client. |
+-------------+---------------------+----------------------------------------+
| int64_t | connection_id | A connection id, this is used when |
| | | further information is exchanged with |
| | | the tracker, to identify you. |
| | | This connection id can be reused for |
| | | multiple requests, but if it's cached |
| | | for too long, it will not be valid |
| | | anymore. |
+-------------+---------------------+----------------------------------------+
announcing
----------
Client sends packet:
+-------------+---------------------+----------------------------------------+
| size | name | description |
+=============+=====================+========================================+
| int64_t | connection_id | The connection id acquired from |
| | | establishing the connection. |
+-------------+---------------------+----------------------------------------+
| int32_t | action | Action. in this case, 1 for announce. |
+-------------+---------------------+----------------------------------------+
| int32_t | transaction_id | Randomized by client. |
+-------------+---------------------+----------------------------------------+
| int8_t[20] | info_hash | The info-hash of the torrent you want |
| | | announce yourself in. |
+-------------+---------------------+----------------------------------------+
| int8_t[20] | peer_id | Your peer id. |
+-------------+---------------------+----------------------------------------+
| int64_t | downloaded | The number of byte you've downloaded |
| | | in this session. |
+-------------+---------------------+----------------------------------------+
| int64_t | left | The number of bytes you have left to |
| | | download until you're finished. |
+-------------+---------------------+----------------------------------------+
| int64_t | uploaded | The number of bytes you have uploaded |
| | | in this session. |
+-------------+---------------------+----------------------------------------+
| int32_t | event | The event, one of |
| | | |
| | | * none = 0 |
| | | * completed = 1 |
| | | * started = 2 |
| | | * stopped = 3 |
+-------------+---------------------+----------------------------------------+
| uint32_t | ip | Your ip address. Set to 0 if you want |
| | | the tracker to use the ``sender`` of |
| | | this udp packet. |
+-------------+---------------------+----------------------------------------+
| int32_t | num_want | The maximum number of peers you want |
| | | in the reply. Use -1 for default. |
+-------------+---------------------+----------------------------------------+
| uint16_t | port | The port you're listening on. |
+-------------+---------------------+----------------------------------------+
Server replies with packet:
+-------------+---------------------+----------------------------------------+
| size | name | description |
+=============+=====================+========================================+
| int32_t | action | The action this is a reply to. Should |
| | | in this case be 1 for announce. |
| | | If 3 (for error) see errors_. |
+-------------+---------------------+----------------------------------------+
| int32_t | transaction_id | Must match the transaction_id sent |
| | | in the announce request. |
+-------------+---------------------+----------------------------------------+
| int32_t | interval | the number of seconds you should wait |
| | | until reannouncing yourself. |
+-------------+---------------------+----------------------------------------+
The rest of the server reply is a variable number of the following structure:
+-------------+---------------------+----------------------------------------+
| size | name | description |
+=============+=====================+========================================+
| int32_t | ip | The ip of a peer in the swarm. |
+-------------+---------------------+----------------------------------------+
| uint16_t | port | The peer's listen port. |
+-------------+---------------------+----------------------------------------+
scraping
--------
Client sends packet:
+-------------+---------------------+----------------------------------------+
| size | name | description |
+=============+=====================+========================================+
| int64_t | connection_id | The connection id retreived from the |
| | | establishing of the connection. |
+-------------+---------------------+----------------------------------------+
| int32_t | action | The action, in this case, 2 for |
| | | scrape. |
+-------------+---------------------+----------------------------------------+
| int32_t | transaction_id | Randomized by client. |
+-------------+---------------------+----------------------------------------+
| int8_t[20] | info_hash | The info hash that is to be scraped. |
+-------------+---------------------+----------------------------------------+
Server replies with packet:
+-------------+---------------------+----------------------------------------+
| size | name | description |
+=============+=====================+========================================+
| int32_t | action | The action, should in this case be |
| | | 2 for scrape. |
| | | If 3 (for error) see errors_. |
+-------------+---------------------+----------------------------------------+
| int32_t | transaction_id | Must match the sent transaction id. |
+-------------+---------------------+----------------------------------------+
The rest of the packet contains a variable number of the following structures:
+-------------+---------------------+----------------------------------------+
| size | name | description |
+=============+=====================+========================================+
| int8_t[20] | info_hash | The info hash of this info. |
+-------------+---------------------+----------------------------------------+
| int32_t | complete | The total number of completed |
| | | downloads. |
+-------------+---------------------+----------------------------------------+
| int32_t | downloaded | The current number of connected seeds. |
+-------------+---------------------+----------------------------------------+
| int32_t | incomplete | The current number of connected |
| | | leechers. |
+-------------+---------------------+----------------------------------------+
errors
------
In case of a tracker error, the server replies with this packet:
+-------------+---------------------+----------------------------------------+
| size | name | description |
+=============+=====================+========================================+
| int32_t | action | The action, in this case 3, for error. |
+-------------+---------------------+----------------------------------------+
| int32_t | transaction_id | Must match the transaction_id sent |
| | | from the client. |
+-------------+---------------------+----------------------------------------+
| int8_t[] | error_string | The rest of the packet is a string |
| | | describing the error. |
+-------------+---------------------+----------------------------------------+
actions
-------
The action fields has the following encoding:
* connect = 0
* announce = 1
* scrape = 2
* error = 3 (only in server replies)
credits
-------
Protocol designed by Olaf van der Spek