From 910733f29e93b60e45aea98f175c3ff3e2659ecf Mon Sep 17 00:00:00 2001
From: Arvid Norberg <arvid@libtorrent.org>
Date: Wed, 27 Sep 2006 17:20:18 +0000
Subject: [PATCH] added proper support for dht router nodes (which are
 automatically used to bootstrap from, and won't get added to the routing
 table)

---
 docs/manual.html                              | 222 ++++++++++--------
 docs/manual.rst                               |  24 +-
 examples/client_test.cpp                      |  15 +-
 include/libtorrent/kademlia/dht_tracker.hpp   |   5 +-
 include/libtorrent/kademlia/node.hpp          |   1 +
 include/libtorrent/kademlia/routing_table.hpp |  15 ++
 .../kademlia/traversal_algorithm.hpp          |  11 +
 include/libtorrent/peer_connection.hpp        |   2 +-
 include/libtorrent/session.hpp                |   1 +
 src/kademlia/dht_tracker.cpp                  |  24 +-
 src/kademlia/node.cpp                         |   5 +
 src/kademlia/routing_table.cpp                |  11 +-
 src/session.cpp                               |  13 +-
 13 files changed, 228 insertions(+), 121 deletions(-)

diff --git a/docs/manual.html b/docs/manual.html
index d0ad9794e..46180610b 100755
--- a/docs/manual.html
+++ b/docs/manual.html
@@ -40,125 +40,126 @@
 <li><a class="reference" href="#is-listening-listen-port-listen-on" id="id28" name="id28">is_listening() listen_port() listen_on()</a></li>
 <li><a class="reference" href="#pop-alert-set-severity-level" id="id29" name="id29">pop_alert() set_severity_level()</a></li>
 <li><a class="reference" href="#start-dht-stop-dht-set-dht-settings-dht-state" id="id30" name="id30">start_dht() stop_dht() set_dht_settings() dht_state()</a></li>
+<li><a class="reference" href="#add-dht-node-add-dht-router" id="id31" name="id31">add_dht_node() add_dht_router()</a></li>
 </ul>
 </li>
-<li><a class="reference" href="#entry" id="id31" name="id31">entry</a><ul>
-<li><a class="reference" href="#integer-string-list-dict-type" id="id32" name="id32">integer() string() list() dict() type()</a></li>
-<li><a class="reference" href="#operator" id="id33" name="id33">operator[]</a></li>
-<li><a class="reference" href="#find-key" id="id34" name="id34">find_key()</a></li>
+<li><a class="reference" href="#entry" id="id32" name="id32">entry</a><ul>
+<li><a class="reference" href="#integer-string-list-dict-type" id="id33" name="id33">integer() string() list() dict() type()</a></li>
+<li><a class="reference" href="#operator" id="id34" name="id34">operator[]</a></li>
+<li><a class="reference" href="#find-key" id="id35" name="id35">find_key()</a></li>
 </ul>
 </li>
-<li><a class="reference" href="#torrent-info" id="id35" name="id35">torrent_info</a><ul>
-<li><a class="reference" href="#id3" id="id36" name="id36">torrent_info()</a></li>
-<li><a class="reference" href="#set-comment-set-piece-size-set-creator-set-hash-add-tracker-add-file" id="id37" name="id37">set_comment() set_piece_size() set_creator() set_hash() add_tracker() add_file()</a></li>
-<li><a class="reference" href="#create-torrent" id="id38" name="id38">create_torrent()</a></li>
-<li><a class="reference" href="#begin-files-end-files-rbegin-files-rend-files" id="id39" name="id39">begin_files() end_files() rbegin_files() rend_files()</a></li>
-<li><a class="reference" href="#num-files-file-at" id="id40" name="id40">num_files() file_at()</a></li>
-<li><a class="reference" href="#map-block" id="id41" name="id41">map_block()</a></li>
-<li><a class="reference" href="#map-file" id="id42" name="id42">map_file()</a></li>
-<li><a class="reference" href="#url-seeds" id="id43" name="id43">url_seeds()</a></li>
-<li><a class="reference" href="#print" id="id44" name="id44">print()</a></li>
-<li><a class="reference" href="#trackers" id="id45" name="id45">trackers()</a></li>
-<li><a class="reference" href="#total-size-piece-length-piece-size-num-pieces" id="id46" name="id46">total_size() piece_length() piece_size() num_pieces()</a></li>
-<li><a class="reference" href="#hash-for-piece-info-hash" id="id47" name="id47">hash_for_piece() info_hash()</a></li>
-<li><a class="reference" href="#name-comment-creation-date-creator" id="id48" name="id48">name() comment() creation_date() creator()</a></li>
-<li><a class="reference" href="#priv-set-priv" id="id49" name="id49">priv() set_priv()</a></li>
-<li><a class="reference" href="#nodes" id="id50" name="id50">nodes()</a></li>
-<li><a class="reference" href="#add-node" id="id51" name="id51">add_node()</a></li>
+<li><a class="reference" href="#torrent-info" id="id36" name="id36">torrent_info</a><ul>
+<li><a class="reference" href="#id3" id="id37" name="id37">torrent_info()</a></li>
+<li><a class="reference" href="#set-comment-set-piece-size-set-creator-set-hash-add-tracker-add-file" id="id38" name="id38">set_comment() set_piece_size() set_creator() set_hash() add_tracker() add_file()</a></li>
+<li><a class="reference" href="#create-torrent" id="id39" name="id39">create_torrent()</a></li>
+<li><a class="reference" href="#begin-files-end-files-rbegin-files-rend-files" id="id40" name="id40">begin_files() end_files() rbegin_files() rend_files()</a></li>
+<li><a class="reference" href="#num-files-file-at" id="id41" name="id41">num_files() file_at()</a></li>
+<li><a class="reference" href="#map-block" id="id42" name="id42">map_block()</a></li>
+<li><a class="reference" href="#map-file" id="id43" name="id43">map_file()</a></li>
+<li><a class="reference" href="#url-seeds" id="id44" name="id44">url_seeds()</a></li>
+<li><a class="reference" href="#print" id="id45" name="id45">print()</a></li>
+<li><a class="reference" href="#trackers" id="id46" name="id46">trackers()</a></li>
+<li><a class="reference" href="#total-size-piece-length-piece-size-num-pieces" id="id47" name="id47">total_size() piece_length() piece_size() num_pieces()</a></li>
+<li><a class="reference" href="#hash-for-piece-info-hash" id="id48" name="id48">hash_for_piece() info_hash()</a></li>
+<li><a class="reference" href="#name-comment-creation-date-creator" id="id49" name="id49">name() comment() creation_date() creator()</a></li>
+<li><a class="reference" href="#priv-set-priv" id="id50" name="id50">priv() set_priv()</a></li>
+<li><a class="reference" href="#nodes" id="id51" name="id51">nodes()</a></li>
+<li><a class="reference" href="#add-node" id="id52" name="id52">add_node()</a></li>
 </ul>
 </li>
-<li><a class="reference" href="#torrent-handle" id="id52" name="id52">torrent_handle</a><ul>
-<li><a class="reference" href="#file-progress" id="id53" name="id53">file_progress()</a></li>
-<li><a class="reference" href="#save-path" id="id54" name="id54">save_path()</a></li>
-<li><a class="reference" href="#move-storage" id="id55" name="id55">move_storage()</a></li>
-<li><a class="reference" href="#force-reannounce" id="id56" name="id56">force_reannounce()</a></li>
-<li><a class="reference" href="#connect-peer" id="id57" name="id57">connect_peer()</a></li>
-<li><a class="reference" href="#set-ratio" id="id58" name="id58">set_ratio()</a></li>
-<li><a class="reference" href="#set-upload-limit-set-download-limit" id="id59" name="id59">set_upload_limit() set_download_limit()</a></li>
-<li><a class="reference" href="#set-sequenced-download-threshold" id="id60" name="id60">set_sequenced_download_threshold()</a></li>
-<li><a class="reference" href="#set-peer-upload-limit-set-peer-download-limit" id="id61" name="id61">set_peer_upload_limit() set_peer_download_limit()</a></li>
-<li><a class="reference" href="#pause-resume-is-paused" id="id62" name="id62">pause() resume() is_paused()</a></li>
-<li><a class="reference" href="#is-seed" id="id63" name="id63">is_seed()</a></li>
-<li><a class="reference" href="#has-metadata" id="id64" name="id64">has_metadata()</a></li>
-<li><a class="reference" href="#set-tracker-login" id="id65" name="id65">set_tracker_login()</a></li>
-<li><a class="reference" href="#trackers-replace-trackers" id="id66" name="id66">trackers() replace_trackers()</a></li>
-<li><a class="reference" href="#add-url-seed" id="id67" name="id67">add_url_seed()</a></li>
-<li><a class="reference" href="#use-interface" id="id68" name="id68">use_interface()</a></li>
-<li><a class="reference" href="#info-hash" id="id69" name="id69">info_hash()</a></li>
-<li><a class="reference" href="#id5" id="id70" name="id70">set_max_uploads() set_max_connections()</a></li>
-<li><a class="reference" href="#write-resume-data" id="id71" name="id71">write_resume_data()</a></li>
-<li><a class="reference" href="#metadata" id="id72" name="id72">metadata()</a></li>
-<li><a class="reference" href="#id6" id="id73" name="id73">status()</a></li>
-<li><a class="reference" href="#get-download-queue" id="id74" name="id74">get_download_queue()</a></li>
-<li><a class="reference" href="#get-peer-info" id="id75" name="id75">get_peer_info()</a></li>
-<li><a class="reference" href="#get-torrent-info" id="id76" name="id76">get_torrent_info()</a></li>
-<li><a class="reference" href="#is-valid" id="id77" name="id77">is_valid()</a></li>
+<li><a class="reference" href="#torrent-handle" id="id53" name="id53">torrent_handle</a><ul>
+<li><a class="reference" href="#file-progress" id="id54" name="id54">file_progress()</a></li>
+<li><a class="reference" href="#save-path" id="id55" name="id55">save_path()</a></li>
+<li><a class="reference" href="#move-storage" id="id56" name="id56">move_storage()</a></li>
+<li><a class="reference" href="#force-reannounce" id="id57" name="id57">force_reannounce()</a></li>
+<li><a class="reference" href="#connect-peer" id="id58" name="id58">connect_peer()</a></li>
+<li><a class="reference" href="#set-ratio" id="id59" name="id59">set_ratio()</a></li>
+<li><a class="reference" href="#set-upload-limit-set-download-limit" id="id60" name="id60">set_upload_limit() set_download_limit()</a></li>
+<li><a class="reference" href="#set-sequenced-download-threshold" id="id61" name="id61">set_sequenced_download_threshold()</a></li>
+<li><a class="reference" href="#set-peer-upload-limit-set-peer-download-limit" id="id62" name="id62">set_peer_upload_limit() set_peer_download_limit()</a></li>
+<li><a class="reference" href="#pause-resume-is-paused" id="id63" name="id63">pause() resume() is_paused()</a></li>
+<li><a class="reference" href="#is-seed" id="id64" name="id64">is_seed()</a></li>
+<li><a class="reference" href="#has-metadata" id="id65" name="id65">has_metadata()</a></li>
+<li><a class="reference" href="#set-tracker-login" id="id66" name="id66">set_tracker_login()</a></li>
+<li><a class="reference" href="#trackers-replace-trackers" id="id67" name="id67">trackers() replace_trackers()</a></li>
+<li><a class="reference" href="#add-url-seed" id="id68" name="id68">add_url_seed()</a></li>
+<li><a class="reference" href="#use-interface" id="id69" name="id69">use_interface()</a></li>
+<li><a class="reference" href="#info-hash" id="id70" name="id70">info_hash()</a></li>
+<li><a class="reference" href="#id5" id="id71" name="id71">set_max_uploads() set_max_connections()</a></li>
+<li><a class="reference" href="#write-resume-data" id="id72" name="id72">write_resume_data()</a></li>
+<li><a class="reference" href="#metadata" id="id73" name="id73">metadata()</a></li>
+<li><a class="reference" href="#id6" id="id74" name="id74">status()</a></li>
+<li><a class="reference" href="#get-download-queue" id="id75" name="id75">get_download_queue()</a></li>
+<li><a class="reference" href="#get-peer-info" id="id76" name="id76">get_peer_info()</a></li>
+<li><a class="reference" href="#get-torrent-info" id="id77" name="id77">get_torrent_info()</a></li>
+<li><a class="reference" href="#is-valid" id="id78" name="id78">is_valid()</a></li>
 </ul>
 </li>
-<li><a class="reference" href="#torrent-status" id="id78" name="id78">torrent_status</a></li>
-<li><a class="reference" href="#peer-info" id="id79" name="id79">peer_info</a></li>
-<li><a class="reference" href="#session-settings" id="id80" name="id80">session_settings</a></li>
-<li><a class="reference" href="#ip-filter" id="id81" name="id81">ip_filter</a><ul>
-<li><a class="reference" href="#id8" id="id82" name="id82">ip_filter()</a></li>
-<li><a class="reference" href="#add-rule" id="id83" name="id83">add_rule()</a></li>
-<li><a class="reference" href="#access" id="id84" name="id84">access()</a></li>
-<li><a class="reference" href="#export-filter" id="id85" name="id85">export_filter()</a></li>
+<li><a class="reference" href="#torrent-status" id="id79" name="id79">torrent_status</a></li>
+<li><a class="reference" href="#peer-info" id="id80" name="id80">peer_info</a></li>
+<li><a class="reference" href="#session-settings" id="id81" name="id81">session_settings</a></li>
+<li><a class="reference" href="#ip-filter" id="id82" name="id82">ip_filter</a><ul>
+<li><a class="reference" href="#id8" id="id83" name="id83">ip_filter()</a></li>
+<li><a class="reference" href="#add-rule" id="id84" name="id84">add_rule()</a></li>
+<li><a class="reference" href="#access" id="id85" name="id85">access()</a></li>
+<li><a class="reference" href="#export-filter" id="id86" name="id86">export_filter()</a></li>
 </ul>
 </li>
-<li><a class="reference" href="#big-number" id="id86" name="id86">big_number</a></li>
-<li><a class="reference" href="#hasher" id="id87" name="id87">hasher</a></li>
-<li><a class="reference" href="#fingerprint" id="id88" name="id88">fingerprint</a></li>
-<li><a class="reference" href="#free-functions" id="id89" name="id89">free functions</a><ul>
-<li><a class="reference" href="#identify-client" id="id90" name="id90">identify_client()</a></li>
-<li><a class="reference" href="#client-fingerprint" id="id91" name="id91">client_fingerprint()</a></li>
-<li><a class="reference" href="#bdecode-bencode" id="id92" name="id92">bdecode() bencode()</a></li>
+<li><a class="reference" href="#big-number" id="id87" name="id87">big_number</a></li>
+<li><a class="reference" href="#hasher" id="id88" name="id88">hasher</a></li>
+<li><a class="reference" href="#fingerprint" id="id89" name="id89">fingerprint</a></li>
+<li><a class="reference" href="#free-functions" id="id90" name="id90">free functions</a><ul>
+<li><a class="reference" href="#identify-client" id="id91" name="id91">identify_client()</a></li>
+<li><a class="reference" href="#client-fingerprint" id="id92" name="id92">client_fingerprint()</a></li>
+<li><a class="reference" href="#bdecode-bencode" id="id93" name="id93">bdecode() bencode()</a></li>
 </ul>
 </li>
-<li><a class="reference" href="#alerts" id="id93" name="id93">alerts</a><ul>
-<li><a class="reference" href="#listen-failed-alert" id="id94" name="id94">listen_failed_alert</a></li>
-<li><a class="reference" href="#file-error-alert" id="id95" name="id95">file_error_alert</a></li>
-<li><a class="reference" href="#tracker-announce-alert" id="id96" name="id96">tracker_announce_alert</a></li>
-<li><a class="reference" href="#tracker-alert" id="id97" name="id97">tracker_alert</a></li>
-<li><a class="reference" href="#tracker-reply-alert" id="id98" name="id98">tracker_reply_alert</a></li>
-<li><a class="reference" href="#tracker-warning-alert" id="id99" name="id99">tracker_warning_alert</a></li>
-<li><a class="reference" href="#url-seed-alert" id="id100" name="id100">url_seed_alert</a></li>
-<li><a class="reference" href="#hash-failed-alert" id="id101" name="id101">hash_failed_alert</a></li>
-<li><a class="reference" href="#peer-ban-alert" id="id102" name="id102">peer_ban_alert</a></li>
-<li><a class="reference" href="#peer-error-alert" id="id103" name="id103">peer_error_alert</a></li>
-<li><a class="reference" href="#invalid-request-alert" id="id104" name="id104">invalid_request_alert</a></li>
-<li><a class="reference" href="#torrent-finished-alert" id="id105" name="id105">torrent_finished_alert</a></li>
-<li><a class="reference" href="#metadata-failed-alert" id="id106" name="id106">metadata_failed_alert</a></li>
-<li><a class="reference" href="#metadata-received-alert" id="id107" name="id107">metadata_received_alert</a></li>
-<li><a class="reference" href="#fastresume-rejected-alert" id="id108" name="id108">fastresume_rejected_alert</a></li>
-<li><a class="reference" href="#dispatcher" id="id109" name="id109">dispatcher</a></li>
+<li><a class="reference" href="#alerts" id="id94" name="id94">alerts</a><ul>
+<li><a class="reference" href="#listen-failed-alert" id="id95" name="id95">listen_failed_alert</a></li>
+<li><a class="reference" href="#file-error-alert" id="id96" name="id96">file_error_alert</a></li>
+<li><a class="reference" href="#tracker-announce-alert" id="id97" name="id97">tracker_announce_alert</a></li>
+<li><a class="reference" href="#tracker-alert" id="id98" name="id98">tracker_alert</a></li>
+<li><a class="reference" href="#tracker-reply-alert" id="id99" name="id99">tracker_reply_alert</a></li>
+<li><a class="reference" href="#tracker-warning-alert" id="id100" name="id100">tracker_warning_alert</a></li>
+<li><a class="reference" href="#url-seed-alert" id="id101" name="id101">url_seed_alert</a></li>
+<li><a class="reference" href="#hash-failed-alert" id="id102" name="id102">hash_failed_alert</a></li>
+<li><a class="reference" href="#peer-ban-alert" id="id103" name="id103">peer_ban_alert</a></li>
+<li><a class="reference" href="#peer-error-alert" id="id104" name="id104">peer_error_alert</a></li>
+<li><a class="reference" href="#invalid-request-alert" id="id105" name="id105">invalid_request_alert</a></li>
+<li><a class="reference" href="#torrent-finished-alert" id="id106" name="id106">torrent_finished_alert</a></li>
+<li><a class="reference" href="#metadata-failed-alert" id="id107" name="id107">metadata_failed_alert</a></li>
+<li><a class="reference" href="#metadata-received-alert" id="id108" name="id108">metadata_received_alert</a></li>
+<li><a class="reference" href="#fastresume-rejected-alert" id="id109" name="id109">fastresume_rejected_alert</a></li>
+<li><a class="reference" href="#dispatcher" id="id110" name="id110">dispatcher</a></li>
 </ul>
 </li>
-<li><a class="reference" href="#exceptions" id="id110" name="id110">exceptions</a><ul>
-<li><a class="reference" href="#invalid-handle" id="id111" name="id111">invalid_handle</a></li>
-<li><a class="reference" href="#duplicate-torrent" id="id112" name="id112">duplicate_torrent</a></li>
-<li><a class="reference" href="#invalid-encoding" id="id113" name="id113">invalid_encoding</a></li>
-<li><a class="reference" href="#type-error" id="id114" name="id114">type_error</a></li>
-<li><a class="reference" href="#invalid-torrent-file" id="id115" name="id115">invalid_torrent_file</a></li>
+<li><a class="reference" href="#exceptions" id="id111" name="id111">exceptions</a><ul>
+<li><a class="reference" href="#invalid-handle" id="id112" name="id112">invalid_handle</a></li>
+<li><a class="reference" href="#duplicate-torrent" id="id113" name="id113">duplicate_torrent</a></li>
+<li><a class="reference" href="#invalid-encoding" id="id114" name="id114">invalid_encoding</a></li>
+<li><a class="reference" href="#type-error" id="id115" name="id115">type_error</a></li>
+<li><a class="reference" href="#invalid-torrent-file" id="id116" name="id116">invalid_torrent_file</a></li>
 </ul>
 </li>
-<li><a class="reference" href="#fast-resume" id="id116" name="id116">fast resume</a><ul>
-<li><a class="reference" href="#file-format" id="id117" name="id117">file format</a></li>
+<li><a class="reference" href="#fast-resume" id="id117" name="id117">fast resume</a><ul>
+<li><a class="reference" href="#file-format" id="id118" name="id118">file format</a></li>
 </ul>
 </li>
-<li><a class="reference" href="#threads" id="id118" name="id118">threads</a></li>
-<li><a class="reference" href="#storage-allocation" id="id119" name="id119">storage allocation</a><ul>
-<li><a class="reference" href="#full-allocation" id="id120" name="id120">full allocation</a></li>
-<li><a class="reference" href="#compact-allocation" id="id121" name="id121">compact allocation</a></li>
+<li><a class="reference" href="#threads" id="id119" name="id119">threads</a></li>
+<li><a class="reference" href="#storage-allocation" id="id120" name="id120">storage allocation</a><ul>
+<li><a class="reference" href="#full-allocation" id="id121" name="id121">full allocation</a></li>
+<li><a class="reference" href="#compact-allocation" id="id122" name="id122">compact allocation</a></li>
 </ul>
 </li>
-<li><a class="reference" href="#extensions" id="id122" name="id122">extensions</a><ul>
-<li><a class="reference" href="#chat-messages" id="id123" name="id123">chat messages</a></li>
-<li><a class="reference" href="#metadata-from-peers" id="id124" name="id124">metadata from peers</a></li>
-<li><a class="reference" href="#http-seeding" id="id125" name="id125">HTTP seeding</a></li>
+<li><a class="reference" href="#extensions" id="id123" name="id123">extensions</a><ul>
+<li><a class="reference" href="#chat-messages" id="id124" name="id124">chat messages</a></li>
+<li><a class="reference" href="#metadata-from-peers" id="id125" name="id125">metadata from peers</a></li>
+<li><a class="reference" href="#http-seeding" id="id126" name="id126">HTTP seeding</a></li>
 </ul>
 </li>
-<li><a class="reference" href="#filename-checks" id="id126" name="id126">filename checks</a></li>
-<li><a class="reference" href="#acknowledgments" id="id127" name="id127">acknowledgments</a></li>
+<li><a class="reference" href="#filename-checks" id="id127" name="id127">filename checks</a></li>
+<li><a class="reference" href="#acknowledgments" id="id128" name="id128">acknowledgments</a></li>
 </ul>
 </div>
 <div class="section" id="overview">
@@ -274,7 +275,8 @@ class session: public boost::noncopyable
         entry dht_state() const;
         void add_dht_node(std::pair&lt;std::string
                 , int&gt; const&amp; node);
-
+        void add_dht_router(std::pair&lt;std::string
+                , int&gt; const&amp; node);
 };
 </pre>
 <p>Once it's created, the session object will spawn the main thread that will do all the work.
@@ -547,7 +549,6 @@ void start_dht(entry const&amp; startup_state);
 void stop_dht();
 void set_dht_settings(dht_settings const&amp; settings);
 entry dht_state() const;
-void add_dht_node(std::pair&lt;std::string, int&gt; const&amp; node);
 </pre>
 </blockquote>
 <p>These functions are not available in case <tt class="docutils literal"><span class="pre">TORRENT_DISABLE_DHT</span></tt> is
@@ -595,6 +596,25 @@ that are ready to replace a failing node, it will be replaced immediately,
 this limit is only used to clear out nodes that don't have any node that can
 replace them.</p>
 </div>
+<div class="section" id="add-dht-node-add-dht-router">
+<h2><a name="add-dht-node-add-dht-router">add_dht_node() add_dht_router()</a></h2>
+<blockquote>
+<pre class="literal-block">
+void add_dht_node(std::pair&lt;std::string, int&gt; const&amp; node);
+void add_dht_router(std::pair&lt;std::string, int&gt; const&amp; node);
+</pre>
+</blockquote>
+<p><tt class="docutils literal"><span class="pre">add_dht_node</span></tt> takes a host name and port pair. That endpoint will be
+pinged, and if a valid DHT reply is received, the node will be added to
+the routing table.</p>
+<p><tt class="docutils literal"><span class="pre">add_dht_router</span></tt> adds the given endpoint to a list of DHT router nodes.
+If a search is ever made while the routing table is empty, those nodes will
+be used as backups. Nodes in the router node list will also never be added
+to the regular routing table, which effectively means they are only used
+for bootstrapping, to keep the load off them.</p>
+<p>An example routing node that you could typically add is
+<tt class="docutils literal"><span class="pre">router.bittorrent.com</span></tt>.</p>
+</div>
 </div>
 <div class="section" id="entry">
 <h1><a name="entry">entry</a></h1>
@@ -2458,7 +2478,7 @@ struct peer_error_alert: alert
 <div class="section" id="invalid-request-alert">
 <h2><a name="invalid-request-alert">invalid_request_alert</a></h2>
 <p>This is a debug alert that is generated by an incoming invalid piece request. The <tt class="docutils literal"><span class="pre">handle</span></tt>
-is a handle to the torrent the peer is a member of. <tt class="docutils literal"><span class="pre">ìp</span></tt> is the address of the peer and the
+is a handle to the torrent the peer is a member of. <tt class="docutils literal"><span class="pre">Ïp</span></tt> is the address of the peer and the
 <tt class="docutils literal"><span class="pre">request</span></tt> is the actual incoming request from the peer. The alert is generated as severity level
 <tt class="docutils literal"><span class="pre">debug</span></tt>.</p>
 <pre class="literal-block">
@@ -3051,7 +3071,7 @@ boost::filesystem::path::default_name_check(boost::filesystem::native);
 <p>Big thanks to Michael Wojciechowski and Peter Koeleman for making the autotools
 scripts.</p>
 <p>Thanks to Reimond Retz for bugfixes, suggestions and testing</p>
-<p>Thanks to <a class="reference" href="http://www.cs.umu.se">University of Umeå</a> for providing development and test hardware.</p>
+<p>Thanks to <a class="reference" href="http://www.cs.umu.se">University of UmeÂ</a> for providing development and test hardware.</p>
 <p>Project is hosted by sourceforge.</p>
 <p><a class="reference" href="http://sourceforge.net"><img alt="sf_logo" src="http://sourceforge.net/sflogo.php?group_id=7994" /></a></p>
 </div>
diff --git a/docs/manual.rst b/docs/manual.rst
index 971053a31..0347d0cdb 100755
--- a/docs/manual.rst
+++ b/docs/manual.rst
@@ -120,7 +120,8 @@ The ``session`` class has the following synopsis::
 		entry dht_state() const;
 		void add_dht_node(std::pair<std::string
 			, int> const& node);
-
+		void add_dht_router(std::pair<std::string
+			, int> const& node);
 	};
 
 Once it's created, the session object will spawn the main thread that will do all the work.
@@ -420,7 +421,6 @@ start_dht() stop_dht() set_dht_settings() dht_state()
 		void stop_dht();
 		void set_dht_settings(dht_settings const& settings);
 		entry dht_state() const;
-		void add_dht_node(std::pair<std::string, int> const& node);
 
 These functions are not available in case ``TORRENT_DISABLE_DHT`` is
 defined. ``start_dht`` starts the dht node and makes the trackerless service
@@ -474,6 +474,26 @@ that are ready to replace a failing node, it will be replaced immediately,
 this limit is only used to clear out nodes that don't have any node that can
 replace them.
 
+add_dht_node() add_dht_router()
+-------------------------------
+
+	::
+
+		void add_dht_node(std::pair<std::string, int> const& node);
+		void add_dht_router(std::pair<std::string, int> const& node);
+
+``add_dht_node`` takes a host name and port pair. That endpoint will be
+pinged, and if a valid DHT reply is received, the node will be added to
+the routing table.
+
+``add_dht_router`` adds the given endpoint to a list of DHT router nodes.
+If a search is ever made while the routing table is empty, those nodes will
+be used as backups. Nodes in the router node list will also never be added
+to the regular routing table, which effectively means they are only used
+for bootstrapping, to keep the load off them.
+
+An example routing node that you could typically add is
+``router.bittorrent.com``.
 
 
 entry
diff --git a/examples/client_test.cpp b/examples/client_test.cpp
index e5ab6543f..7ea5e7b35 100755
--- a/examples/client_test.cpp
+++ b/examples/client_test.cpp
@@ -575,14 +575,15 @@ int main(int ac, char* av[])
 			entry dht_state = bdecode(
 				std::istream_iterator<char>(dht_state_file)
 				, std::istream_iterator<char>());
-			ses.start_dht(dht_state);
-		}
-		catch (std::exception&)
-		{
-			ses.start_dht();
-			ses.add_dht_node(std::make_pair(std::string("router.bittorrent.com")
-				, 6881));
 		}
+		catch (std::exception&) {}
+		ses.start_dht();
+		ses.add_dht_router(std::make_pair(std::string("router.bittorrent.com")
+			, 6881));
+		ses.add_dht_router(std::make_pair(std::string("router.utorrent.com")
+			, 6881));
+		ses.add_dht_router(std::make_pair(std::string("router.bitcomet.com")
+			, 6881));
 #endif
 
 		ses.set_max_half_open_connections(half_open_limit);
diff --git a/include/libtorrent/kademlia/dht_tracker.hpp b/include/libtorrent/kademlia/dht_tracker.hpp
index 2c35a5105..d447d4b23 100644
--- a/include/libtorrent/kademlia/dht_tracker.hpp
+++ b/include/libtorrent/kademlia/dht_tracker.hpp
@@ -67,7 +67,8 @@ namespace libtorrent { namespace dht
 
 		void add_node(udp::endpoint node);
 		void add_node(std::pair<std::string, int> const& node);
-		
+		void add_router_node(std::pair<std::string, int> const& node);
+
 		void rebind(asio::ip::address listen_interface, int listen_port);
 
 		entry state() const;
@@ -82,6 +83,8 @@ namespace libtorrent { namespace dht
 
 		void on_name_lookup(asio::error const& e
 			, udp::resolver::iterator host);
+		void on_router_name_lookup(asio::error const& e
+			, udp::resolver::iterator host);
 		void connection_timeout(asio::error const& e);
 		void refresh_timeout(asio::error const& e);
 		void tick(asio::error const& e);
diff --git a/include/libtorrent/kademlia/node.hpp b/include/libtorrent/kademlia/node.hpp
index e5660c03d..c44a21f33 100644
--- a/include/libtorrent/kademlia/node.hpp
+++ b/include/libtorrent/kademlia/node.hpp
@@ -99,6 +99,7 @@ public:
 		, boost::function0<void> f);
 	void find_node(node_id const& id, boost::function<
 	void(std::vector<node_entry> const&)> f);
+	void add_router_node(udp::endpoint router);
 		
 	void incoming(msg const& m);
 
diff --git a/include/libtorrent/kademlia/routing_table.hpp b/include/libtorrent/kademlia/routing_table.hpp
index 96449bda1..1b4abbf37 100644
--- a/include/libtorrent/kademlia/routing_table.hpp
+++ b/include/libtorrent/kademlia/routing_table.hpp
@@ -156,6 +156,15 @@ public:
 		, dht_settings const& settings);
 
 	void node_failed(node_id const& id);
+	
+	// adds an endpoint that will never be added to
+	// the routing table
+	void add_router_node(udp::endpoint router);
+
+	// iterates over the router nodes added
+	typedef std::set<udp::endpoint>::const_iterator router_iterator;
+	router_iterator router_begin() const { return m_router_nodes.begin(); }
+	router_iterator router_end() const { return m_router_nodes.end(); }
 
 	// this function is called every time the node sees
 	// a sign of a node being alive. This node will either
@@ -220,6 +229,12 @@ private:
 	table_activity_t m_bucket_activity;
 	node_id m_id; // our own node id
 	
+	// this is a set of all the endpoints that have
+	// been identified as router nodes. They will
+	// be used in searches, but they will never
+	// be added to the routing table.
+	std::set<udp::endpoint> m_router_nodes;
+	
 	// this is the lowest bucket index with nodes in it
 	int m_lowest_active_bucket;
 };
diff --git a/include/libtorrent/kademlia/traversal_algorithm.hpp b/include/libtorrent/kademlia/traversal_algorithm.hpp
index ce6176f56..a99a9c6ea 100644
--- a/include/libtorrent/kademlia/traversal_algorithm.hpp
+++ b/include/libtorrent/kademlia/traversal_algorithm.hpp
@@ -141,6 +141,17 @@ traversal_algorithm::traversal_algorithm(
 	{
 		add_entry(i->id, i->addr, result::initial);
 	}
+	
+	// in case the routing table is empty, use the
+	// router nodes in the table
+	if (start == end)
+	{
+		for (routing_table::router_iterator i = table.router_begin()
+			, end(table.router_end()); i != end; ++i)
+		{
+			add_entry(node_id(0), *i, result::initial);
+		}
+	}
 
 }
 
diff --git a/include/libtorrent/peer_connection.hpp b/include/libtorrent/peer_connection.hpp
index 77fed37ff..9201551d3 100755
--- a/include/libtorrent/peer_connection.hpp
+++ b/include/libtorrent/peer_connection.hpp
@@ -413,7 +413,7 @@ namespace libtorrent
 
 		boost::shared_ptr<stream_socket> m_socket;
 		tcp::endpoint m_remote;
-		
+
 		// this is the torrent this connection is
 		// associated with. If the connection is an
 		// incoming conncetion, this is set to zero
diff --git a/include/libtorrent/session.hpp b/include/libtorrent/session.hpp
index 27a0da2f8..5f13f6d21 100755
--- a/include/libtorrent/session.hpp
+++ b/include/libtorrent/session.hpp
@@ -382,6 +382,7 @@ namespace libtorrent
 		void set_dht_settings(dht_settings const& settings);
 		entry dht_state() const;
 		void add_dht_node(std::pair<std::string, int> const& node);
+		void add_dht_router(std::pair<std::string, int> const& node);
 #endif
 
 		void enable_extension(extension_index i);
diff --git a/src/kademlia/dht_tracker.cpp b/src/kademlia/dht_tracker.cpp
index 57d2f6212..131d1cdfc 100644
--- a/src/kademlia/dht_tracker.cpp
+++ b/src/kademlia/dht_tracker.cpp
@@ -649,9 +649,9 @@ namespace libtorrent { namespace dht
 		m_host_resolver.async_resolve(q, bind(&dht_tracker::on_name_lookup
 			, this, _1, _2));
 	}
-	
-	void dht_tracker::on_name_lookup(asio::error const& e, udp::resolver::iterator host)
-		try
+
+	void dht_tracker::on_name_lookup(asio::error const& e
+		, udp::resolver::iterator host) try
 	{
 		if (e || host == udp::resolver::iterator()) return;
 		add_node(host->endpoint());
@@ -661,6 +661,24 @@ namespace libtorrent { namespace dht
 		assert(false);
 	};
 
+	void dht_tracker::add_router_node(std::pair<std::string, int> const& node)
+	{
+		udp::resolver::query q(node.first, lexical_cast<std::string>(node.second));
+		m_host_resolver.async_resolve(q, bind(&dht_tracker::on_router_name_lookup
+			, this, _1, _2));
+	}
+
+	void dht_tracker::on_router_name_lookup(asio::error const& e
+		, udp::resolver::iterator host) try
+	{
+		if (e || host == udp::resolver::iterator()) return;
+		m_dht.add_router_node(host->endpoint());
+	}
+	catch (std::exception&)
+	{
+		assert(false);
+	};
+
 	void dht_tracker::on_bootstrap()
 	{}
 
diff --git a/src/kademlia/node.cpp b/src/kademlia/node.cpp
index 46e5708ec..8a9d17818 100644
--- a/src/kademlia/node.cpp
+++ b/src/kademlia/node.cpp
@@ -347,6 +347,11 @@ namespace
 	};
 }
 
+void node_impl::add_router_node(udp::endpoint router)
+{
+	m_table.add_router_node(router);
+}
+
 void node_impl::add_node(udp::endpoint node)
 {
 	// ping the node, and if we get a reply, it
diff --git a/src/kademlia/routing_table.cpp b/src/kademlia/routing_table.cpp
index 2d85849d3..66900cc42 100644
--- a/src/kademlia/routing_table.cpp
+++ b/src/kademlia/routing_table.cpp
@@ -221,6 +221,11 @@ void routing_table::node_failed(node_id const& id)
 	rb.erase(rb.end() - 1);
 }
 
+void routing_table::add_router_node(udp::endpoint router)
+{
+	m_router_nodes.insert(router);
+}
+
 // this function is called every time the node sees
 // a sign of a node being alive. This node will either
 // be inserted in the k-buckets or be moved to the top
@@ -230,6 +235,7 @@ void routing_table::node_failed(node_id const& id)
 // on its own id)
 bool routing_table::node_seen(node_id const& id, udp::endpoint addr)
 {
+	if (m_router_nodes.find(addr) != m_router_nodes.end()) return false;
 	int bucket_index = distance_exp(m_id, id);
 	assert(bucket_index < (int)m_buckets.size());
 	assert(bucket_index >= 0);
@@ -266,7 +272,10 @@ bool routing_table::node_seen(node_id const& id, udp::endpoint addr)
 	if ((int)b.size() < m_bucket_size)
 	{
 		b.push_back(node_entry(id, addr));
-		if (bucket_index < m_lowest_active_bucket)
+		// if bucket index is 0, the node is ourselves
+		// don't updated m_lowest_active_bucket
+		if (bucket_index < m_lowest_active_bucket
+			&& bucket_index > 0)
 			m_lowest_active_bucket = bucket_index;
 //		TORRENT_LOG(table) << "inserting node: " << id << " " << addr;
 		return ret;
diff --git a/src/session.cpp b/src/session.cpp
index 942947959..56e2218f7 100755
--- a/src/session.cpp
+++ b/src/session.cpp
@@ -672,8 +672,7 @@ namespace libtorrent { namespace detail
 #if defined(TORRENT_VERBOSE_LOGGING) || defined(TORRENT_LOGGING)
 		(*m_logger) << endp << " <== INCOMING CONNECTION\n";
 #endif
-		if (endp.address().is_v4()
-			&& (m_ip_filter.access(endp.address().to_v4()) & ip_filter::blocked))
+		if (m_ip_filter.access(endp.address().to_v4()) & ip_filter::blocked)
 		{
 #if defined(TORRENT_VERBOSE_LOGGING) || defined(TORRENT_LOGGING)
 			(*m_logger) << "filtered blocked ip\n";
@@ -1175,9 +1174,7 @@ namespace libtorrent
 			= m_impl.m_connections.begin(); i != m_impl.m_connections.end();)
 		{
 			tcp::endpoint sender = i->first->remote_endpoint();
-			if (sender.address().is_v4()
-				&& (m_impl.m_ip_filter.access(sender.address().to_v4())
-				& ip_filter::blocked))
+			if (m_impl.m_ip_filter.access(sender.address()) & ip_filter::blocked)
 			{
 #if defined(TORRENT_VERBOSE_LOGGING)
 				(*i->second->m_logger) << "*** CONNECTION FILTERED'\n";
@@ -1541,6 +1538,12 @@ namespace libtorrent
 		m_impl.m_dht->add_node(node);
 	}
 
+	void session::add_dht_router(std::pair<std::string, int> const& node)
+	{
+		assert(m_impl.m_dht);
+		m_impl.m_dht->add_router_node(node);
+	}
+
 #endif
 
 	bool session::is_listening() const