send implied_port in dht announce messages when uTP is enabled

include/libtorrent/kademlia/dht_tracker.hpp

@@ -89,7 +89,8 @@ namespace libtorrent { namespace dht
 
 		entry state() const;
 
-		void announce(sha1_hash const& ih, int listen_port, bool seed
+		enum flags_t { flag_seed = 1, flag_implied_port = 2 };
+		void announce(sha1_hash const& ih, int listen_port, int flags
 			, boost::function<void(std::vector<tcp::endpoint> const&)> f);
 
 		void dht_status(session_status& s);

include/libtorrent/kademlia/node.hpp

@@ -232,7 +232,8 @@ public:
 	{ m_table.print_state(os); }
 #endif
 
-	void announce(sha1_hash const& info_hash, int listen_port, bool seed
+	enum flags_t { flag_seed = 1, flag_implied_port = 2 };
+	void announce(sha1_hash const& info_hash, int listen_port, int flags
 		, boost::function<void(std::vector<tcp::endpoint> const&)> f);
 
 	void get_item(sha1_hash const& target, boost::function<bool(item&)> f);

src/kademlia/dht_tracker.cpp

@@ -416,10 +416,10 @@ namespace libtorrent { namespace dht
 #endif
 	}
 
-	void dht_tracker::announce(sha1_hash const& ih, int listen_port, bool seed
+	void dht_tracker::announce(sha1_hash const& ih, int listen_port, int flags
 		, boost::function<void(std::vector<tcp::endpoint> const&)> f)
 	{
-		m_dht.announce(ih, listen_port, seed, f);
+		m_dht.announce(ih, listen_port, flags, f);
 	}
 
 

src/kademlia/node.cpp

@@ -294,7 +294,7 @@ void node_impl::incoming(msg const& m)
 namespace
 {
 	void announce_fun(std::vector<std::pair<node_entry, std::string> > const& v
-		, node_impl& node, int listen_port, sha1_hash const& ih, bool seed)
+		, node_impl& node, int listen_port, sha1_hash const& ih, int flags)
 	{
 #ifdef TORRENT_DHT_VERBOSE_LOGGING
 		TORRENT_LOG(node) << "sending announce_peer [ ih: " << ih
@@ -327,8 +327,8 @@ namespace
 			a["info_hash"] = ih.to_string();
 			a["port"] = listen_port;
 			a["token"] = i->second;
-			a["seed"] = int(seed);
+			a["seed"] = (flags & node_impl::flag_seed) ? 1 : 0;
-			// TODO: 3 if uTP is enabled, we should say "implied_port": 1
+			if (flags & node_impl::flag_implied_port) a["implied_port"] = 1;
 			node.m_rpc.invoke(e, i->first.ep(), o);
 		}
 	}
@@ -364,7 +364,7 @@ void node_impl::add_node(udp::endpoint node)
 	m_rpc.invoke(e, node, o);
 }
 
-void node_impl::announce(sha1_hash const& info_hash, int listen_port, bool seed
+void node_impl::announce(sha1_hash const& info_hash, int listen_port, int flags
 	, boost::function<void(std::vector<tcp::endpoint> const&)> f)
 {
 #ifdef TORRENT_DHT_VERBOSE_LOGGING
@@ -378,13 +378,13 @@ void node_impl::announce(sha1_hash const& info_hash, int listen_port, bool seed
 	{
 		ta.reset(new obfuscated_get_peers(*this, info_hash, f
 			, boost::bind(&announce_fun, _1, boost::ref(*this)
-			, listen_port, info_hash, seed), seed));
+			, listen_port, info_hash, flags), flags & node_impl::flag_seed));
 	}
 	else
 	{
 		ta.reset(new get_peers(*this, info_hash, f
 			, boost::bind(&announce_fun, _1, boost::ref(*this)
-			, listen_port, info_hash, seed), seed));
+			, listen_port, info_hash, flags), flags & node_impl::flag_seed));
 	}
 
 	ta->start();

src/torrent.cpp

@@ -2139,8 +2139,17 @@ namespace libtorrent
 #endif
 
 		boost::weak_ptr<torrent> self(shared_from_this());
+
+		// if we're a seed, we tell the DHT for better scrape stats
+		int flags = is_seed() ? dht::dht_tracker::flag_seed : 0;
+		// if we allow incoming uTP connections, set the implied_port
+		// argument in the announce, this will make the DHT node use
+		// our source port in the packet as our listen port, which is
+		// likely more accurate when behind a NAT
+		if (settings().enable_incoming_utp) flags |= dht::dht_tracker::flag_implied_port;
+
 		m_ses.m_dht->announce(m_torrent_file->info_hash()
-			, port, is_seed()
+			, port, flags
 			, boost::bind(&torrent::on_dht_announce_response_disp, self, _1));
 	}