improved DHT get_peers code. get_peers always returns nodes now, and announce_peer is always sent to the k closest nodes to the info-hash. This should significantly speed up retrieving peers from the DHT

docs/dht_extensions.rst

@@ -5,6 +5,16 @@ Mainline DHT extensions
 
 libtorrent implements a few extensions to the Mainline DHT protocol.
 
+get_peers response
+------------------
+
+libtorrent always responds with ``nodes`` to a get_peers request. If it has
+peers for the specified info-hash, it will return ``values`` as well. This is
+because just because some peer announced to us, doesn't mean that we are
+among the 8 closest nodes of the info hash. libtorrent also keeps traversing
+nodes using get_peers until it has found the 8 closest ones, and then announces
+to those nodes.
+
 client identification
 ---------------------
 

include/libtorrent/kademlia/dht_tracker.hpp

@@ -90,8 +90,7 @@ namespace libtorrent { namespace dht
 		entry state() const;
 
 		void announce(sha1_hash const& ih, int listen_port
-			, boost::function<void(std::vector<tcp::endpoint> const&
+			, boost::function<void(std::vector<tcp::endpoint> const&)> f);
-			, sha1_hash const&)> f);
 
 		void dht_status(session_status& s);
 		void network_stats(int& sent, int& received);

include/libtorrent/kademlia/find_data.hpp

@@ -34,6 +34,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #define FIND_DATA_050323_HPP
 
 #include <vector>
+#include <map>
 
 #include <libtorrent/kademlia/traversal_algorithm.hpp>
 #include <libtorrent/kademlia/node_id.hpp>
@@ -58,22 +59,29 @@ class node_impl;
 class find_data : public traversal_algorithm
 {
 public:
-	typedef boost::function<void(msg const*)> done_callback;
+	typedef boost::function<void(std::vector<tcp::endpoint> const&)> data_callback;
+	typedef boost::function<void(std::vector<std::pair<node_entry, std::string> > const&)> nodes_callback;
 
 	void got_data(msg const* m);
+	void got_write_token(node_id const& n, std::string const& write_token)
+	{ m_write_tokens[n] = write_token; }
 
 	find_data(node_impl& node, node_id target
-		, done_callback const& callback);
+		, data_callback const& dcallback
+		, nodes_callback const& ncallback);
 
 	virtual char const* name() const { return "get_peers"; }
+	node_id const target() const { return m_target; }
 
 private:
 
 	void done();
 	void invoke(node_id const& id, udp::endpoint addr);
 
-	done_callback m_done_callback;
+	data_callback m_data_callback;
-	boost::shared_ptr<packet_t> m_packet;
+	nodes_callback m_nodes_callback;
+	std::map<node_id, std::string> m_write_tokens;
+	node_id const m_target;
 	bool m_done;
 };
 
@@ -82,11 +90,9 @@ class find_data_observer : public observer
 public:
 	find_data_observer(
 		boost::intrusive_ptr<find_data> const& algorithm
-		, node_id self
+		, node_id self)
-		, node_id target)
 		: observer(algorithm->allocator())
 		, m_algorithm(algorithm)
-		, m_target(target) 
 		, m_self(self)
 	{}
 	~find_data_observer();
@@ -95,7 +101,7 @@ public:
 	{
 		m.reply = false;
 		m.message_id = messages::get_peers;
-		m.info_hash = m_target;
+		m.info_hash = m_algorithm->target();
 	}
 
 	void timeout();
@@ -104,7 +110,6 @@ public:
 
 private:
 	boost::intrusive_ptr<find_data> m_algorithm;
-	node_id const m_target;
 	node_id const m_self;
 };
 

include/libtorrent/kademlia/node.hpp

@@ -125,46 +125,6 @@ private:
 	std::string m_token;
 };
 
-class get_peers_observer : public observer
-{
-public:
-	get_peers_observer(sha1_hash const& info_hash
-		, int listen_port
-		, rpc_manager& rpc
-		, boost::function<void(std::vector<tcp::endpoint> const&, sha1_hash const&)> f)
-		: observer(rpc.allocator())
-		, m_info_hash(info_hash)
-		, m_listen_port(listen_port)
-		, m_rpc(rpc)
-		, m_fun(f)
-	{}
-
-	void send(msg& m)
-	{
-		m.port = m_listen_port;
-		m.info_hash = m_info_hash;
-	}
-
-	void timeout() {}
-	void reply(msg const& r)
-	{
-		observer_ptr o(new (m_rpc.allocator().malloc()) announce_observer(
-			m_rpc.allocator(), m_info_hash, m_listen_port, r.write_token));
-#ifdef TORRENT_DEBUG
-		o->m_in_constructor = false;
-#endif
-		m_rpc.invoke(messages::announce_peer, r.addr, o);
-		m_fun(r.peers, m_info_hash);
-	}
-	void abort() {}
-
-private:
-	sha1_hash m_info_hash;
-	int m_listen_port;
-	rpc_manager& m_rpc;
-	boost::function<void(std::vector<tcp::endpoint> const&, sha1_hash const&)> m_fun;
-};
-
 class node_impl : boost::noncopyable
 {
 typedef std::map<node_id, torrent_entry> table_t;
@@ -211,8 +171,7 @@ public:
 #endif
 
 	void announce(sha1_hash const& info_hash, int listen_port
-		, boost::function<void(std::vector<tcp::endpoint> const&
+		, boost::function<void(std::vector<tcp::endpoint> const&)> f);
-			, sha1_hash const&)> f);
 
 	bool verify_token(msg const& m);
 	std::string generate_token(msg const& m);

parse_dht_stats.py

@@ -42,11 +42,11 @@ replot
 	gnuplot_scripts += [name]
 
 gen_stats_gnuplot('dht_routing_table_size', 'nodes', ['active nodes','passive nodes'])
-gen_stats_gnuplot('dht_tracker_table_size', '', ['num torrents'])
+gen_stats_gnuplot('dht_tracker_table_size', '', ['num torrents', 'num peers'])
-gen_stats_gnuplot('dht_announces', 'number per minute', ['announces per min', 'failed announces per min'])
+gen_stats_gnuplot('dht_announces', 'messages per minute', ['announces per min', 'failed announces per min'])
-gen_stats_gnuplot('dht_clients', 'number per minute', ['total msgs per min', 'az msgs per min', 'ut msgs per min', 'lt msgs per min', 'mp msgs per min', 'gr msgs per min'])
+gen_stats_gnuplot('dht_clients', 'messages per minute', ['total msgs per min', 'az msgs per min', 'ut msgs per min', 'lt msgs per min', 'mp msgs per min', 'gr msgs per min'])
 gen_stats_gnuplot('dht_rate', 'bytes per second',  ['bytes in per sec', 'bytes out per sec'])
-gen_stats_gnuplot('dht_errors', '',  ['error replies sent', 'error queries recvd'])
+gen_stats_gnuplot('dht_errors', 'messages per minute',  ['error replies sent', 'error queries recvd'])
 
 for i in gnuplot_scripts:
 	os.system('gnuplot %s.gnuplot' % i);

src/kademlia/dht_tracker.cpp

@@ -207,7 +207,7 @@ namespace libtorrent { namespace dht
 		// turns on and off individual components' logging
 
 		rpc_log().enable(false);
-		node_log().enable(false);
+//		node_log().enable(false);
 		traversal_log().enable(false);
 //		dht_tracker_log.enable(false);
 
@@ -325,7 +325,7 @@ namespace libtorrent { namespace dht
 			m_last_new_key = now;
 			m_dht.new_write_key();
 #ifdef TORRENT_DHT_VERBOSE_LOGGING
-			TORRENT_LOG(dht_tracker) << time_now_string() << " new write key";
+			TORRENT_LOG(dht_tracker) << " *** new write key";
 #endif
 		}
 		
@@ -410,8 +410,7 @@ namespace libtorrent { namespace dht
 	}
 
 	void dht_tracker::announce(sha1_hash const& ih, int listen_port
-		, boost::function<void(std::vector<tcp::endpoint> const&
+		, boost::function<void(std::vector<tcp::endpoint> const&)> f)
-		, sha1_hash const&)> f)
 	{
 		mutex_t::scoped_lock l(m_mutex);
 		m_dht.announce(ih, listen_port, f);
@@ -609,6 +608,9 @@ namespace libtorrent { namespace dht
 			std::copy(id->string_ptr(), id->string_ptr()
 				+ id->string_length(), m.id.begin());
 
+#ifdef TORRENT_DHT_VERBOSE_LOGGING
+			log_line << " id: " << m.id;
+#endif
 			lazy_entry const* n = r->dict_find_list("values");
 			if (n)
 			{
@@ -804,6 +806,7 @@ namespace libtorrent { namespace dht
 				m.write_token = token->string_value();
 				m.message_id = libtorrent::dht::messages::announce_peer;
 #ifdef TORRENT_DHT_VERBOSE_LOGGING
+				log_line << " token: " << to_hex(m.write_token);
 				log_line << " ih: " << boost::lexical_cast<std::string>(m.info_hash);
 				log_line << " p: " << m.port;
 
@@ -1037,11 +1040,9 @@ namespace libtorrent { namespace dht
 				}
 				case messages::get_peers:
 				{
-					if (m.peers.empty())
+					write_nodes_entry(r, m);
-					{
+
-						write_nodes_entry(r, m);
+					if (!m.peers.empty())
-					}
-					else
 					{
 						r["values"] = entry(entry::list_t);
 						entry& p = r["values"];

src/kademlia/find_data.cpp

@@ -55,11 +55,13 @@ void find_data_observer::reply(msg const& m)
 		return;
 	}
 
+	if (!m.write_token.empty())
+		m_algorithm->got_write_token(m.id, m.write_token);
+
 	if (!m.peers.empty())
-	{
 		m_algorithm->got_data(&m);
-	}
+
-	else
+	if (!m.nodes.empty())
 	{
 		for (msg::nodes_t::const_iterator i = m.nodes.begin()
 			, end(m.nodes.end()); i != end; ++i)
@@ -82,9 +84,12 @@ void find_data_observer::timeout()
 find_data::find_data(
 	node_impl& node
 	, node_id target
-	, done_callback const& callback)
+	, data_callback const& dcallback
+	, nodes_callback const& ncallback)
 	: traversal_algorithm(node, target, node.m_table.begin(), node.m_table.end())
-	, m_done_callback(callback)
+	, m_data_callback(dcallback)
+	, m_nodes_callback(ncallback)
+	, m_target(target)
 	, m_done(false)
 {
 	boost::intrusive_ptr<find_data> self(this);
@@ -100,7 +105,7 @@ void find_data::invoke(node_id const& id, udp::endpoint addr)
 	}
 
 	TORRENT_ASSERT(m_node.m_rpc.allocation_size() >= sizeof(find_data_observer));
-	observer_ptr o(new (m_node.m_rpc.allocator().malloc()) find_data_observer(this, id, m_target));
+	observer_ptr o(new (m_node.m_rpc.allocator().malloc()) find_data_observer(this, id));
 #ifdef TORRENT_DEBUG
 	o->m_in_constructor = false;
 #endif
@@ -109,14 +114,26 @@ void find_data::invoke(node_id const& id, udp::endpoint addr)
 
 void find_data::got_data(msg const* m)
 {
-	m_done = true;
+	m_data_callback(m->peers);
-	m_done_callback(m);
 }
 
 void find_data::done()
 {
 	if (m_invoke_count != 0) return;
-	if (!m_done) m_done_callback(0);
+
+	std::vector<std::pair<node_entry, std::string> > results;
+	int num_results = m_node.m_table.bucket_size();
+	for (std::vector<result>::iterator i = m_results.begin()
+		, end(m_results.end()); i != end && num_results > 0; ++i)
+	{
+		if (i->flags & result::no_id) continue;
+		if ((i->flags & result::queried) == 0) continue;
+		std::map<node_id, std::string>::iterator j = m_write_tokens.find(i->id);
+		if (j == m_write_tokens.end()) continue;
+		results.push_back(std::make_pair(node_entry(i->id, i->addr), j->second));
+		--num_results;
+	}
+	m_nodes_callback(results);
 }
 
 } } // namespace libtorrent::dht

src/kademlia/node.cpp

@@ -172,12 +172,14 @@ void node_impl::refresh(node_id const& id
 void node_impl::bootstrap(std::vector<udp::endpoint> const& nodes
 	, boost::function0<void> f)
 {
+/*
 #ifdef TORRENT_DHT_VERBOSE_LOGGING
 	TORRENT_LOG(node) << "bootrapping: " << nodes.size();
 	for (std::vector<udp::endpoint>::const_iterator i = nodes.begin()
 		, end(nodes.end()); i != end; ++i)
 		TORRENT_LOG(node) << "  " << *i;
 #endif
+*/
 	std::vector<node_entry> start;
 	start.reserve(nodes.size());
 	std::copy(nodes.begin(), nodes.end(), std::back_inserter(start));
@@ -255,29 +257,29 @@ void node_impl::incoming(msg const& m)
 
 namespace
 {
-	void announce_fun(std::vector<node_entry> const& v, rpc_manager& rpc
+	void announce_fun(std::vector<std::pair<node_entry, std::string> > const& v
-		, int listen_port, sha1_hash const& ih
+		, rpc_manager& rpc, int listen_port, sha1_hash const& ih)
-		, boost::function<void(std::vector<tcp::endpoint> const&, sha1_hash const&)> f)
 	{
 #ifdef TORRENT_DHT_VERBOSE_LOGGING
-		TORRENT_LOG(node) << "announce response [ ih: " << ih
+		TORRENT_LOG(node) << "sending announce_peer [ ih: " << ih
 			<< " p: " << listen_port
 			<< " nodes: " << v.size() << " ]" ;
 #endif
-		bool nodes = false;
+		
-		// only store on the first k nodes
+		// store on the first k nodes
-		for (std::vector<node_entry>::const_iterator i = v.begin()
+		for (std::vector<std::pair<node_entry, std::string> >::const_iterator i = v.begin()
 			, end(v.end()); i != end; ++i)
 		{
 #ifdef TORRENT_DHT_VERBOSE_LOGGING
-			TORRENT_LOG(node) << "  distance: " << (160 - distance_exp(ih, i->id));
+			TORRENT_LOG(node) << "  distance: " << (160 - distance_exp(ih, i->first.id));
 #endif
-			observer_ptr o(new (rpc.allocator().malloc()) get_peers_observer(ih, listen_port, rpc, f));
+
+			observer_ptr o(new (rpc.allocator().malloc()) announce_observer(
+				rpc.allocator(), ih, listen_port, i->second));
 #ifdef TORRENT_DEBUG
 			o->m_in_constructor = false;
 #endif
-			rpc.invoke(messages::get_peers, udp::endpoint(i->addr, i->port), o);
+			rpc.invoke(messages::announce_peer, i->first.ep(), o);
-			nodes = true;
 		}
 	}
 }
@@ -302,15 +304,15 @@ void node_impl::add_node(udp::endpoint node)
 }
 
 void node_impl::announce(sha1_hash const& info_hash, int listen_port
-	, boost::function<void(std::vector<tcp::endpoint> const&, sha1_hash const&)> f)
+	, boost::function<void(std::vector<tcp::endpoint> const&)> f)
 {
 #ifdef TORRENT_DHT_VERBOSE_LOGGING
 	TORRENT_LOG(node) << "announcing [ ih: " << info_hash << " p: " << listen_port << " ]" ;
 #endif
-	// search for nodes with ids close to id, and then invoke the
+	// search for nodes with ids close to id or with peers
-	// get_peers and then announce_peer rpc on them.
+	// for info-hash id. then send announce_peer to them.
-	new closest_nodes(*this, info_hash, boost::bind(&announce_fun, _1, boost::ref(m_rpc)
+	new find_data(*this, info_hash, f, boost::bind(&announce_fun, _1, boost::ref(m_rpc)
-		, listen_port, info_hash, f));
+		, listen_port, info_hash));
 }
 
 time_duration node_impl::refresh_timeout()
@@ -443,7 +445,7 @@ bool node_impl::on_find(msg const& m, std::vector<tcp::endpoint>& peers) const
 	random_sample_n(boost::make_transform_iterator(v.peers.begin(), &get_endpoint)
 		, boost::make_transform_iterator(v.peers.end(), &get_endpoint)
 		, std::back_inserter(peers), num);
-
+/*
 #ifdef TORRENT_DHT_VERBOSE_LOGGING
 	for (std::vector<tcp::endpoint>::iterator i = peers.begin()
 		, end(peers.end()); i != end; ++i)
@@ -451,6 +453,7 @@ bool node_impl::on_find(msg const& m, std::vector<tcp::endpoint>& peers) const
 		TORRENT_LOG(node) << "   " << *i;
 	}
 #endif
+*/
 	return true;
 }
 
@@ -471,26 +474,10 @@ void node_impl::incoming_request(msg const& m)
 			reply.info_hash = m.info_hash;
 			reply.write_token = generate_token(m);
 			
-			if (!on_find(m, reply.peers))
+			on_find(m, reply.peers);
-			{
+			// always return nodes as well as peers
-				// we don't have any peers for this info_hash,
-				// return nodes instead
-				m_table.find_node(m.info_hash, reply.nodes, 0);
-#ifdef TORRENT_DHT_VERBOSE_LOGGING
-				for (std::vector<node_entry>::iterator i = reply.nodes.begin()
-					, end(reply.nodes.end()); i != end; ++i)
-				{
-					TORRENT_LOG(node) << "	" << i->id << " " << i->ep();
-				}
-#endif
-			}
-		}
-		break;
-	case messages::find_node:
-		{
-			reply.info_hash = m.info_hash;
-
 			m_table.find_node(m.info_hash, reply.nodes, 0);
+/*
 #ifdef TORRENT_DHT_VERBOSE_LOGGING
 			for (std::vector<node_entry>::iterator i = reply.nodes.begin()
 				, end(reply.nodes.end()); i != end; ++i)
@@ -498,6 +485,23 @@ void node_impl::incoming_request(msg const& m)
 				TORRENT_LOG(node) << "	" << i->id << " " << i->ep();
 			}
 #endif
+*/
+		}
+		break;
+	case messages::find_node:
+		{
+			reply.info_hash = m.info_hash;
+
+			m_table.find_node(m.info_hash, reply.nodes, 0);
+/*
+#ifdef TORRENT_DHT_VERBOSE_LOGGING
+			for (std::vector<node_entry>::iterator i = reply.nodes.begin()
+				, end(reply.nodes.end()); i != end; ++i)
+			{
+				TORRENT_LOG(node) << "	" << i->id << " " << i->ep();
+			}
+#endif
+*/
 		}
 		break;
 	case messages::announce_peer:

src/kademlia/rpc_manager.cpp

@@ -93,7 +93,6 @@ typedef mpl::vector<
 	closest_nodes_observer
 	, find_data_observer
 	, announce_observer
-	, get_peers_observer
 	, refresh_observer
 	, ping_observer
 	, null_observer
@@ -117,6 +116,16 @@ rpc_manager::rpc_manager(fun const& f, node_id const& our_id
 	, m_destructing(false)
 {
 	std::srand(time(0));
+
+#ifdef TORRENT_DHT_VERBOSE_LOGGING
+	TORRENT_LOG(rpc) << "Constructing";
+	TORRENT_LOG(rpc) << " closest_nodes_observer: " << sizeof(closest_nodes_observer);
+	TORRENT_LOG(rpc) << " find_data_observer: " << sizeof(find_data_observer);
+	TORRENT_LOG(rpc) << " announce_observer: " << sizeof(announce_observer);
+	TORRENT_LOG(rpc) << " refresh_observer: " << sizeof(refresh_observer);
+	TORRENT_LOG(rpc) << " ping_observer: " << sizeof(ping_observer);
+	TORRENT_LOG(rpc) << " null_observer: " << sizeof(null_observer);
+#endif
 }
 
 rpc_manager::~rpc_manager()