Document UDP tracker in manual

README.rst

@@ -54,7 +54,8 @@ Here is a list of features:
 * Persistent Connections support
 * FTP through HTTP Proxy
 * Download/Upload speed throttling
-* BitTorrent extensions: Fast extension, DHT, PEX, MSE/PSE, Multi-Tracker
+* BitTorrent extensions: Fast extension, DHT, PEX, MSE/PSE,
+  Multi-Tracker, UDP tracker
 * BitTorrent `WEB-Seeding <http://getright.com/seedtorrent.html>`_. aria2
   requests chunks more than piece size to reduce the request
   overhead. It also supports pipelined requests with piece size.
@@ -365,6 +366,13 @@ for IPv4 DHT is saved to ``$HOME/.aria2/dht.dat`` and the routing
 table for IPv6 DHT is saved to ``$HOME/.aria2/dht6.dat``. aria2 uses
 same port number to listen on for both IPv4 and IPv6 DHT.
 
+UDP tracker
+~~~~~~~~~~~
+
+UDP tracker support is enabled when IPv4 DHT is enabled.  The port
+number of UDP tracker is shared with DHT. Use ``--dht-listen-port``
+option to change the port number.
+
 Other things should be noted
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 

doc/manual-src/en/aria2c.rst

@@ -727,10 +727,10 @@ BitTorrent Specific Options
 
 .. option:: --dht-listen-port=<PORT>...
 
-  Set UDP listening port for both IPv4 and IPv6 DHT.
-  Multiple ports can be specified by using ``,``, for example: ``6881,6885``.
-  You can also use ``-`` to specify a range: ``6881-6999``. ``,`` and ``-`` can be used
-  together.
+  Set UDP listening port used by DHT(IPv4, IPv6) and UDP tracker.
+  Multiple ports can be specified by using ``,``, for example:
+  ``6881,6885``.  You can also use ``-`` to specify a range:
+  ``6881-6999``. ``,`` and ``-`` can be used together.
   Default: ``6881-6999``
 
   .. note::
@@ -743,9 +743,9 @@ BitTorrent Specific Options
 
 .. option:: --enable-dht[=true|false]
 
-  Enable IPv4 DHT functionality. If a private flag is set in a
-  torrent, aria2 doesn't use DHT for that download even if ``true`` is
-  given.  Default: ``true``
+  Enable IPv4 DHT functionality. It also enables UDP tracker
+  support. If a private flag is set in a torrent, aria2 doesn't use
+  DHT for that download even if ``true`` is given.  Default: ``true``
 
 .. option:: --enable-dht6[=true|false]
 

src/usage_text.h

@@ -309,13 +309,16 @@
 #define TEXT_ENABLE_PEER_EXCHANGE                                       \
   _(" --enable-peer-exchange[=true|false] Enable Peer Exchange extension.")
 #define TEXT_ENABLE_DHT                                         \
-  _(" --enable-dht[=true|false]    Enable IPv4 DHT functionality.")
+  _(" --enable-dht[=true|false]    Enable IPv4 DHT functionality. It also enables\n" \
+    "                              UDP tracker support. If a private flag is set\n" \
+    "                              in a torrent, aria2 doesn't use DHT for that\n" \
+    "                              download even if ``true`` is given.")
 #define TEXT_DHT_LISTEN_PORT                                            \
-  _(" --dht-listen-port=PORT...    Set UDP listening port for both IPv4 and IPv6\n"   \
-    "                              DHT. Multiple ports can be specified by using\n" \
-    "                              ',', for example: \"6881,6885\". You can also\n" \
-    "                              use '-' to specify a range: \"6881-6999\". ','\n" \
-    "                              and '-' can be used together.")
+  _(" --dht-listen-port=PORT...    Set UDP listening port used by DHT(IPv4, IPv6)\n"   \
+    "                              and UDP tracker. Multiple ports can be specified\n" \
+    "                              by using ',', for example: \"6881,6885\". You can\n" \
+    "                              also use '-' to specify a range: \"6881-6999\".\n" \
+    "                              ',' and '-' can be used together.")
 #define TEXT_DHT_ENTRY_POINT                                            \
   _(" --dht-entry-point=HOST:PORT  Set host and port as an entry point to IPv4 DHT\n" \
     "                              network.")