From 2dbfa156d36f3a988ab4e36209575ead56907996 Mon Sep 17 00:00:00 2001
From: Arvid Norberg <arvid@libtorrent.org>
Date: Thu, 8 Mar 2007 21:42:37 +0000
Subject: [PATCH] client test now always uses dht. fixed problem with the dht
 logging and updated dht extension docs.

---
 docs/dht_extensions.html                | 26 ++++++++++++++-----------
 docs/dht_extensions.rst                 | 15 +++++++++-----
 examples/client_test.cpp                |  2 ++
 include/libtorrent/kademlia/logging.hpp |  2 +-
 4 files changed, 28 insertions(+), 17 deletions(-)

diff --git a/docs/dht_extensions.html b/docs/dht_extensions.html
index faa1fb3a8..96c6b39ed 100644
--- a/docs/dht_extensions.html
+++ b/docs/dht_extensions.html
@@ -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>
diff --git a/docs/dht_extensions.rst b/docs/dht_extensions.rst
index 424f90978..6d64a8c18 100644
--- a/docs/dht_extensions.rst
+++ b/docs/dht_extensions.rst
@@ -29,12 +29,17 @@ Currently known clients:
 IPv6 support
 ------------
 
-The only DHT messages that don't support IPv6 is the ``nodes`` reply. It
-encodes all the contacts as 6 bytes sequences packed together in sequence in 
+The DHT messages that don't support IPv6 are the ``nodes`` 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
-``nodes2`` 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).
+``nodes2``.
 
+``nodes2`` may be present in replies that contains a ``nodes`` 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).
+
+As an optimization, libtorrent does not include the extra key in case there are
+only IPv4 nodes present.
 
diff --git a/examples/client_test.cpp b/examples/client_test.cpp
index f46ed1062..7070ec513 100755
--- a/examples/client_test.cpp
+++ b/examples/client_test.cpp
@@ -588,6 +588,8 @@ int main(int ac, char* av[])
 		ses.add_extension(&create_ut_pex_plugin);
 
 #ifndef TORRENT_DISABLE_DHT
+		settings.use_dht_as_fallback = false;
+
 		dht_settings s;
 		s.service_port = listen_port;
 		ses.set_dht_settings(s);
diff --git a/include/libtorrent/kademlia/logging.hpp b/include/libtorrent/kademlia/logging.hpp
index 8bd488f1a..c0cbb31a4 100644
--- a/include/libtorrent/kademlia/logging.hpp
+++ b/include/libtorrent/kademlia/logging.hpp
@@ -133,7 +133,7 @@ public:
 #define TORRENT_DEFINE_LOG(name) \
 	libtorrent::dht::log& name ## _log() \
 	{ \
-		static std::ofstream log_file("libtorrent_logs/dht.log", std::ios::app); \
+		static std::ofstream log_file("dht.log", std::ios::app); \
 		static libtorrent::dht::log instance(#name, log_file); \
 		return instance; \
 	}