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client test now always uses dht. fixed problem with the dht logging and updated dht extension docs.

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Arvid Norberg
2007-03-08 21:42:37 +00:00
parent 6f0a0beadb
commit 2dbfa156d3
4 changed files with 28 additions and 17 deletions
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docs/dht_extensions.html
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@@ -19,11 +19,11 @@
<td>Arvid Norberg, <a class="last reference" href="mailto:arvid&#64;rasterbar.com">arvid&#64;rasterbar.com</a></td></tr>
</tbody>
</table>
<div class="section">
<h1><a id="mainline-dht-extensions" name="mainline-dht-extensions">Mainline DHT extensions</a></h1>
<div class="section" id="mainline-dht-extensions">
<h1>Mainline DHT extensions</h1>
<p>libtorrent implements a few extensions to the Mainline DHT protocol.</p>
<div class="section">
<h2><a id="client-identification" name="client-identification">client identification</a></h2>
<div class="section" id="client-identification">
<h2>client identification</h2>
<p>In each DHT packet, an extra key is inserted named &quot;v&quot;. This is a string
describing the client and version used. This can help alot when debugging
and finding errors in client implementations. The string is encoded as four
@@ -51,15 +51,19 @@ as a binary number describing the client version.</p>
</tbody>
</table>
</div>
<div class="section">
<h2><a id="ipv6-support" name="ipv6-support">IPv6 support</a></h2>
<p>The only DHT messages that don't support IPv6 is the <tt class="docutils literal"><span class="pre">nodes</span></tt> reply. It
encodes all the contacts as 6 bytes sequences packed together in sequence in
<div class="section" id="ipv6-support">
<h2>IPv6 support</h2>
<p>The DHT messages that don't support IPv6 are the <tt class="docutils literal"><span class="pre">nodes</span></tt> replies.
They encode all the contacts as 6 bytes packed together in sequence in a
string. The problem is that IPv6 endpoints cannot be encoded as 6 bytes, but
needs 18 bytes. The extension libtorrent applies is to add another key, called
<tt class="docutils literal"><span class="pre">nodes2</span></tt> which is encoded as a list of strings. Each string represents one
contact and is encoded as 20 bytes node-id and then a variable length encoded
IP address (6 bytes in IPv4 case and 18 bytes in IPv6 case).</p>
<tt class="docutils literal"><span class="pre">nodes2</span></tt>.</p>
<p><tt class="docutils literal"><span class="pre">nodes2</span></tt> may be present in replies that contains a <tt class="docutils literal"><span class="pre">nodes</span></tt> key. It is encoded
as a list of strings. Each string represents one contact and is encoded as 20
bytes node-id and then a variable length encoded IP address (6 bytes in IPv4 case
and 18 bytes in IPv6 case).</p>
<p>As an optimization, libtorrent does not include the extra key in case there are
only IPv4 nodes present.</p>
</div>
</div>
</div>