support dht nodes in magnet links

ChangeLog

@@ -55,6 +55,7 @@
 	* added more detailed instrumentation of the disk I/O thread
 
 
+	* support dht nodes in magnet links
 	* support 100 Continue HTTP responses
 	* changed default choker behavior to use 8 unchoke slots (instead of being rate based)
 	* fixed error reporting issue in disk I/O thread

src/magnet_uri.cpp

@@ -163,6 +163,26 @@ namespace libtorrent
 			return torrent_handle();
 		}
 
+#ifndef TORRENT_DISABLE_DHT
+		std::string::size_type node_pos = std::string::npos;
+		std::string node = url_has_argument(uri, "dht", &node_pos);
+		while (!node.empty())
+		{
+			std::string::size_type divider = node.find_last_of(':');
+			if (divider != std::string::npos)
+			{
+				int port = atoi(node.c_str()+divider+1);
+				if (port != 0)
+					ses.add_dht_node(std::make_pair(node.substr(0, divider), port));
+			}
+			
+			node_pos = uri.find("&dht=", node_pos);
+			if (node_pos == std::string::npos) break;
+			node_pos += 5;
+			node = uri.substr(node_pos, uri.find('&', node_pos) - node_pos);
+		}
+#endif
+
 		sha1_hash info_hash;
 		if (btih.size() == 40 + 9) from_hex(&btih[9], 40, (char*)&info_hash[0]);
 		else info_hash.assign(base32decode(btih.substr(9)));

src/session_impl.cpp

@@ -3678,8 +3678,7 @@ namespace aux {
 
 	void session_impl::add_dht_node_name(std::pair<std::string, int> const& node)
 	{
-		TORRENT_ASSERT(m_dht);
-		m_dht->add_node(node);
+		if (m_dht) m_dht->add_node(node);
 	}
 
 	void session_impl::add_dht_router(std::pair<std::string, int> const& node)
@@ -3694,11 +3693,16 @@ namespace aux {
 	void session_impl::on_dht_router_name_lookup(error_code const& e
 		, tcp::resolver::iterator host)
 	{
-		if (e || host == tcp::resolver::iterator()) return;
+		// TODO: report errors as alerts
+		if (e) return;
+		while (host != tcp::resolver::iterator())
+		{
 			// router nodes should be added before the DHT is started (and bootstrapped)
 			udp::endpoint ep(host->endpoint().address(), host->endpoint().port());
 			if (m_dht) m_dht->add_router_node(ep);
 			m_dht_router_nodes.push_back(ep);
+			++host;
+		}
 	}
 #endif
 

test/test_primitives.cpp

@@ -431,7 +431,7 @@ int test_main()
 	p.save_path = ".";
 	error_code ec;
 	const char* magnet_uri = "magnet:?xt=urn:btih:cdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcd"
-		"&tr=http://1&tr=http://2&tr=http://3&dn=foo";
+		"&tr=http://1&tr=http://2&tr=http://3&dn=foo&dht=127.0.0.1:43";
 	torrent_handle t = add_magnet_uri(*s, magnet_uri, p, ec);
 	TEST_CHECK(!ec);
 	if (ec) fprintf(stderr, "%s\n", ec.message().c_str());