Merge pull request #95 from arvidn/postpone_dht_start

DHT router name lookups

include/libtorrent/aux_/session_impl.hpp

@@ -328,6 +328,8 @@ namespace libtorrent
 			entry dht_state() const;
 #endif
 			void on_dht_announce(error_code const& e);
+			void on_dht_name_lookup(error_code const& e
+				, std::vector<address> const& addresses, int port);
 			void on_dht_router_name_lookup(error_code const& e
 				, std::vector<address> const& addresses, int port);
 #endif
@@ -996,7 +998,11 @@ namespace libtorrent
 
 			// these are used when starting the DHT
 			// (and bootstrapping it), and then erased
-			std::list<udp::endpoint> m_dht_router_nodes;
+			std::vector<udp::endpoint> m_dht_router_nodes;
+
+			// if a DHT node is added when there's no DHT instance, they're stored
+			// here until we start the DHT
+			std::vector<udp::endpoint> m_dht_nodes;
 
 			// this announce timer is used
 			// by the DHT.
@@ -1009,6 +1015,10 @@ namespace libtorrent
 			// is updated again. This especially matters for
 			// small numbers.
 			int m_dht_interval_update_torrents;
+
+			// the number of DHT router lookups there are currently outstanding. As
+			// long as this is > 0, we'll postpone starting the DHT
+			int m_outstanding_router_lookups;
 #endif
 
 			bool incoming_packet(error_code const& ec

include/libtorrent/kademlia/dht_tracker.hpp

@@ -80,7 +80,6 @@ namespace libtorrent { namespace dht
 		void stop();
 
 		void add_node(udp::endpoint node);
-		void add_node(std::pair<std::string, int> const& node);
 		void add_router_node(udp::endpoint const& node);
 
 		entry state() const;
@@ -126,10 +125,6 @@ namespace libtorrent { namespace dht
 		boost::shared_ptr<dht_tracker> self()
 		{ return shared_from_this(); }
 
-		void on_name_lookup(error_code const& e
-			, udp::resolver::iterator host);
-		void on_router_name_lookup(error_code const& e
-			, udp::resolver::iterator host);
 		void connection_timeout(error_code const& e);
 		void refresh_timeout(error_code const& e);
 		void tick(error_code const& e);

src/kademlia/dht_tracker.cpp

@@ -442,22 +442,6 @@ namespace libtorrent { namespace dht
 		m_dht.add_node(node);
 	}
 
-	void dht_tracker::add_node(std::pair<std::string, int> const& node)
-	{
-		char port[7];
-		snprintf(port, sizeof(port), "%d", node.second);
-		udp::resolver::query q(node.first, port);
-		m_host_resolver.async_resolve(q,
-			boost::bind(&dht_tracker::on_name_lookup, self(), _1, _2));
-	}
-
-	void dht_tracker::on_name_lookup(error_code const& e
-		, udp::resolver::iterator host)
-	{
-		if (e || host == udp::resolver::iterator()) return;
-		add_node(host->endpoint());
-	}
-
 	void dht_tracker::add_router_node(udp::endpoint const& node)
 	{
 		m_dht.add_router_node(node);

src/session_impl.cpp

@@ -416,6 +416,7 @@ namespace aux {
 #ifndef TORRENT_DISABLE_DHT
 		, m_dht_announce_timer(m_io_service)
 		, m_dht_interval_update_torrents(0)
+		, m_outstanding_router_lookups(0)
 #endif
 		, m_external_udp_port(0)
 		, m_udp_socket(m_io_service)
@@ -3353,6 +3354,7 @@ retry:
 		TORRENT_ASSERT(is_single_thread());
 
 		if (m_dht) m_dht->add_node(n);
+		else m_dht_nodes.push_back(n);
 	}
 
 	bool session_impl::has_dht() const
@@ -4509,11 +4511,13 @@ retry:
 
 #ifndef TORRENT_DISABLE_DHT
 		// add p.dht_nodes to the DHT, if enabled
-		if (m_dht && !p.dht_nodes.empty())
+		if (!p.dht_nodes.empty())
 		{
 			for (std::vector<std::pair<std::string, int> >::const_iterator i = p.dht_nodes.begin()
 				, end(p.dht_nodes.end()); i != end; ++i)
-				m_dht->add_node(*i);
+			{
+				add_dht_node_name(*i);
+			}
 		}
 #endif
 
@@ -4665,13 +4669,14 @@ retry:
 #endif
 
 #ifndef TORRENT_DISABLE_DHT
-		if (m_dht && params.ti)
+		if (params.ti)
 		{
 			torrent_info::nodes_t const& nodes = params.ti->nodes();
-			std::for_each(nodes.begin(), nodes.end(), boost::bind(
-				static_cast<void(dht::dht_tracker::*)(std::pair<std::string, int> const&)>(
-					&dht::dht_tracker::add_node)
-				, boost::ref(m_dht), _1));
+			for (std::vector<std::pair<std::string, int> >::const_iterator i = nodes.begin()
+				, end(nodes.end()); i != end; ++i)
+			{
+				add_dht_node_name(*i);
+			}
 		}
 #endif
 
@@ -5413,16 +5418,27 @@ retry:
 		INVARIANT_CHECK;
 
 		stop_dht();
+
+		// postpone starting the DHT if we're still resolving the DHT router
+		if (m_outstanding_router_lookups > 0) return;
+
 		m_dht = boost::make_shared<dht::dht_tracker>(static_cast<dht_observer*>(this)
 			, boost::ref(m_udp_socket), boost::cref(m_dht_settings)
 			, boost::ref(m_stats_counters), &startup_state);
 
-		for (std::list<udp::endpoint>::iterator i = m_dht_router_nodes.begin()
+		for (std::vector<udp::endpoint>::iterator i = m_dht_router_nodes.begin()
 			, end(m_dht_router_nodes.end()); i != end; ++i)
 		{
 			m_dht->add_router_node(*i);
 		}
 
+		for (std::vector<udp::endpoint>::iterator i = m_dht_nodes.begin()
+			, end(m_dht_nodes.end()); i != end; ++i)
+		{
+			m_dht->add_node(*i);
+		}
+		m_dht_nodes.clear();
+
 		m_dht->start(startup_state, boost::bind(&on_bootstrap, boost::ref(m_alerts)));
 
 		m_udp_socket.subscribe(m_dht.get());
@@ -5451,7 +5467,35 @@ retry:
 
 	void session_impl::add_dht_node_name(std::pair<std::string, int> const& node)
 	{
-		if (m_dht) m_dht->add_node(node);
+#if defined TORRENT_ASIO_DEBUGGING
+		add_outstanding_async("session_impl::on_dht_name_lookup");
+#endif
+		m_host_resolver.async_resolve(node.first, resolver_interface::abort_on_shutdown
+			, boost::bind(&session_impl::on_dht_name_lookup
+				, this, _1, _2, node.second));
+	}
+
+	void session_impl::on_dht_name_lookup(error_code const& e
+		, std::vector<address> const& addresses, int port)
+	{
+#if defined TORRENT_ASIO_DEBUGGING
+		complete_async("session_impl::on_dht_name_lookup");
+#endif
+
+		if (e)
+		{
+			if (m_alerts.should_post<dht_error_alert>())
+				m_alerts.emplace_alert<dht_error_alert>(
+					dht_error_alert::hostname_lookup, e);
+			return;
+		}
+
+		for (std::vector<address>::const_iterator i = addresses.begin()
+			, end(addresses.end()); i != end; ++i)
+		{
+			udp::endpoint ep(*i, port);
+			add_dht_node(ep);
+		}
 	}
 
 	void session_impl::add_dht_router(std::pair<std::string, int> const& node)
@@ -5459,6 +5503,7 @@ retry:
 #if defined TORRENT_ASIO_DEBUGGING
 		add_outstanding_async("session_impl::on_dht_router_name_lookup");
 #endif
+		++m_outstanding_router_lookups;
 		m_host_resolver.async_resolve(node.first, resolver_interface::abort_on_shutdown
 			, boost::bind(&session_impl::on_dht_router_name_lookup
 				, this, _1, _2, node.second));
@@ -5470,11 +5515,15 @@ retry:
 #if defined TORRENT_ASIO_DEBUGGING
 		complete_async("session_impl::on_dht_router_name_lookup");
 #endif
+		--m_outstanding_router_lookups;
+
 		if (e)
 		{
 			if (m_alerts.should_post<dht_error_alert>())
 				m_alerts.emplace_alert<dht_error_alert>(
 					dht_error_alert::hostname_lookup, e);
+
+			if (m_outstanding_router_lookups == 0) update_dht();
 			return;
 		}
 
@@ -5487,6 +5536,8 @@ retry:
 			if (m_dht) m_dht->add_router_node(ep);
 			m_dht_router_nodes.push_back(ep);
 		}
+
+		if (m_outstanding_router_lookups == 0) update_dht();
 	}
 
 	// callback for dht_immutable_get