support requesting UPnP and NAT-PMP routers for our external IP address

docs/manual.rst

@@ -3992,6 +3992,8 @@ session_settings
 		bool rate_limit_utp;
 
 		int listen_queue_size;
+
+		bool announce_double_nat;
 	};
 
 ``version`` is automatically set to the libtorrent version you're using
@@ -4790,6 +4792,10 @@ expects to receive a lot of connections, or used in a simulator or test, it
 might make sense to raise this number. It will not take affect until listen_on()
 is called again (or for the first time).
 
+if ``announce_double_nat`` is true, the ``&ip=`` argument in tracker requests
+(unless otherwise specified) will be set to the intermediate IP address, if the
+user is double NATed. If ther user is not double NATed, this option has no affect.
+
 pe_settings
 ===========
 

include/libtorrent/aux_/session_impl.hpp

@@ -235,8 +235,8 @@ namespace libtorrent
 
 			// called when a port mapping is successful, or a router returns
 			// a failure to map a port
-			void on_port_mapping(int mapping, int port, error_code const& ec
+			void on_port_mapping(int mapping, address const& ip, int port
-				, int nat_transport);
+				, error_code const& ec, int nat_transport);
 
 			bool is_aborted() const { return m_abort; }
 			bool is_paused() const { return m_paused; }
@@ -301,6 +301,7 @@ namespace libtorrent
 			session_status status() const;
 			void set_peer_id(peer_id const& id);
 			void set_key(int key);
+			address listen_address() const;
 			unsigned short listen_port() const;
 			
 			void abort();
@@ -581,6 +582,11 @@ namespace libtorrent
 			struct listen_socket_t
 			{
 				listen_socket_t(): external_port(0) {}
+
+				// this is typically empty but can be set
+				// to the WAN IP address of NAT-PMP or UPnP router
+				address external_address;
+
 				// this is typically set to the same as the local
 				// listen port. In case a NAT port forward was
 				// successfully opened, this will be set to the

include/libtorrent/natpmp.hpp

@@ -42,7 +42,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "libtorrent/deadline_timer.hpp"
 
 #include <boost/function/function1.hpp>
-#include <boost/function/function3.hpp>
+#include <boost/function/function4.hpp>
 
 namespace libtorrent
 {
@@ -50,7 +50,7 @@ namespace libtorrent
 // int: port mapping index
 // int: external port
 // std::string: error message
-typedef boost::function<void(int, int, error_code const&)> portmap_callback_t;
+typedef boost::function<void(int, address, int, error_code const&)> portmap_callback_t;
 typedef boost::function<void(char const*)> log_callback_t;
 
 class TORRENT_EXPORT natpmp : public intrusive_ptr_base<natpmp>
@@ -75,6 +75,7 @@ private:
 	
 	void update_mapping(int i, mutex::scoped_lock& l);
 	void send_map_request(int i, mutex::scoped_lock& l);
+	void send_get_ip_address_request(mutex::scoped_lock& l);
 	void resend_request(int i, error_code const& e);
 	void on_reply(error_code const& e
 		, std::size_t bytes_transferred);
@@ -142,6 +143,9 @@ private:
 	// used to receive responses in	
 	char m_response_buffer[16];
 
+	// router external IP address
+	address m_external_ip;
+
 	// the endpoint we received the message from
 	udp::endpoint m_remote;
 	

include/libtorrent/session_settings.hpp

@@ -251,6 +251,7 @@ namespace libtorrent
 			, mixed_mode_algorithm(peer_proportional)
 			, rate_limit_utp(false)
 			, listen_queue_size(5)
+			, announce_double_nat(false)
 		{}
 
 		// libtorrent version. Used for forward binary compatibility
@@ -992,6 +993,12 @@ namespace libtorrent
 		// the number of connections to accept while we're
 		// not waiting in an accept() call.
 		int listen_queue_size;
+
+		// if this is true, the &ip= argument in tracker requests
+		// (unless otherwise specified) will be set to the intermediate
+		// IP address if the user is double NATed. If ther user is not
+		// double NATed, this option does not have an affect
+		bool announce_double_nat;
 	};
 
 #ifndef TORRENT_DISABLE_DHT

include/libtorrent/upnp.hpp

@@ -90,12 +90,13 @@ namespace libtorrent
 #endif
 
 // int: port-mapping index
+// address: external address as queried from router
 // int: external port
 // std::string: error message
 // an empty string as error means success
 // a port-mapping index of -1 means it's
 // an informational log message
-typedef boost::function<void(int, int, error_code const&)> portmap_callback_t;
+typedef boost::function<void(int, address, int, error_code const&)> portmap_callback_t;
 typedef boost::function<void(char const*)> log_callback_t;
 
 class TORRENT_EXPORT upnp : public intrusive_ptr_base<upnp>
@@ -147,6 +148,9 @@ private:
 	void on_upnp_xml(error_code const& e
 		, libtorrent::http_parser const& p, rootdevice& d
 		, http_connection& c);
+	void on_upnp_get_ip_address_response(error_code const& e
+		, libtorrent::http_parser const& p, rootdevice& d
+		, http_connection& c);
 	void on_upnp_map_response(error_code const& e
 		, libtorrent::http_parser const& p, rootdevice& d
 		, int mapping, http_connection& c);
@@ -159,6 +163,7 @@ private:
 	void return_error(int mapping, int code, mutex::scoped_lock& l);
 	void log(char const* msg, mutex::scoped_lock& l);
 
+	void get_ip_address(rootdevice& d);
 	void delete_port_mapping(rootdevice& d, int i);
 	void create_port_mapping(http_connection& c, rootdevice& d, int i);
 	void post(upnp::rootdevice const& d, char const* soap
@@ -247,6 +252,7 @@ private:
 		std::string hostname;
 		int port;
 		std::string path;
+		address external_ip;
 
 		int lease_duration;
 		// true if the device supports specifying a

src/http_tracker_connection.cpp

@@ -59,6 +59,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "libtorrent/io.hpp"
 #include "libtorrent/socket.hpp"
 #include "libtorrent/aux_/session_impl.hpp"
+#include "libtorrent/broadcast_socket.hpp" // for is_local
 
 using namespace libtorrent;
 
@@ -180,23 +181,34 @@ namespace libtorrent
 			}
 			else
 #endif
-			if (!settings.announce_ip.empty())
+			if (!m_ses.settings().anonymous_mode)
 			{
-				error_code ec;
+				if (!settings.announce_ip.empty())
-				if (!ec) url += "&ip=" + escape_string(
+				{
-					settings.announce_ip.c_str(), settings.announce_ip.size());
+					url += "&ip=" + escape_string(
-			}
+						settings.announce_ip.c_str(), settings.announce_ip.size());
-
+				}
-			if (!tracker_req().ipv6.empty() && !i2p)
+				else if (m_ses.settings().announce_double_nat
-			{
+					&& is_local(m_ses.listen_address()))
-				url += "&ipv6=";
+				{
-				url += tracker_req().ipv6;
+					// only use the global external listen address here
-			}
+					// if it turned out to be on a local network
-
+					// since otherwise the tracker should use our
-			if (!tracker_req().ipv4.empty() && !i2p)
+					// source IP to determine our origin
-			{
+					url += "&ip=" + print_address(m_ses.listen_address());
-				url += "&ipv4=";
+				}
-				url += tracker_req().ipv4;
+   
+				if (!tracker_req().ipv6.empty() && !i2p)
+				{
+					url += "&ipv6=";
+					url += tracker_req().ipv6;
+				}
+   
+				if (!tracker_req().ipv4.empty() && !i2p)
+				{
+					url += "&ipv4=";
+					url += tracker_req().ipv4;
+				}
 			}
 		}
 

src/natpmp.cpp

@@ -120,6 +120,7 @@ void natpmp::rebind(address const& listen_interface)
 #endif
 	m_socket.async_receive_from(asio::buffer(&m_response_buffer, 16)
 		, m_remote, boost::bind(&natpmp::on_reply, self(), _1, _2));
+	send_get_ip_address_request(l);
 
 	for (std::vector<mapping_t>::iterator i = m_mappings.begin()
 		, end(m_mappings.end()); i != end; ++i)
@@ -132,6 +133,20 @@ void natpmp::rebind(address const& listen_interface)
 	}
 }
 
+void natpmp::send_get_ip_address_request(mutex::scoped_lock& l)
+{
+	using namespace libtorrent::detail;
+
+	char buf[2];
+	char* out = buf;
+	write_uint8(0, out); // NAT-PMP version
+	write_uint8(0, out); // public IP address request opcode
+	log("==> get public IP address", l);
+
+	error_code ec;
+	m_socket.send_to(asio::buffer(buf, sizeof(buf)), m_nat_endpoint, 0, ec);
+}
+
 bool natpmp::get_mapping(int index, int& local_port, int& external_port, int& protocol) const
 {
 	mutex::scoped_lock l(m_mutex);
@@ -164,7 +179,7 @@ void natpmp::disable(error_code const& ec, mutex::scoped_lock& l)
 		i->protocol = none;
 		int index = i - m_mappings.begin();
 		l.unlock();
-		m_callback(index, 0, ec);
+		m_callback(index, address(), 0, ec);
 		l.lock();
 	}
 	close_impl(l);
@@ -337,7 +352,7 @@ void natpmp::send_map_request(int i, mutex::scoped_lock& l)
 	log(msg, l);
 
 	error_code ec;
-	m_socket.send_to(asio::buffer(buf, 12), m_nat_endpoint, 0, ec);
+	m_socket.send_to(asio::buffer(buf, sizeof(buf)), m_nat_endpoint, 0, ec);
 	m.map_sent = true;
 	m.outstanding_request = true;
 	if (m_abort)
@@ -428,11 +443,45 @@ void natpmp::on_reply(error_code const& e
 	error_code ec;
 	m_send_timer.cancel(ec);
 
+	if (bytes_transferred < 12)
+	{
+		char msg[200];
+		snprintf(msg, sizeof(msg), "received packet of invalid size: %d", bytes_transferred);
+		log(msg, l);
+		return;
+	}
+
 	char* in = m_response_buffer;
 	int version = read_uint8(in);
 	int cmd = read_uint8(in);
 	int result = read_uint16(in);
 	int time = read_uint32(in);
+
+	// for some reason the Airport extreme responds with
+	// a cmd of 130 for the public IP request. However, the
+	// response is still identifiable by its size
+	// this might be a bug triggered by libtorrent not serializing
+	// its port mapping requests and the external IP request
+	if (cmd == 128 || bytes_transferred == 12)
+	{
+		// public IP request response
+		m_external_ip = address_v4(read_uint32(in));
+
+		char msg[200];
+		snprintf(msg, sizeof(msg), "<== public IP address [ %s ]", print_address(m_external_ip).c_str());
+		log(msg, l);
+		return;
+
+	}
+
+	if (bytes_transferred < 16)
+	{
+		char msg[200];
+		snprintf(msg, sizeof(msg), "received packet of invalid size: %d", bytes_transferred);
+		log(msg, l);
+		return;
+	}
+
 	int private_port = read_uint16(in);
 	int public_port = read_uint16(in);
 	int lifetime = read_uint32(in);
@@ -505,13 +554,14 @@ void natpmp::on_reply(error_code const& e
 
 		m->expires = time_now() + hours(2);
 		l.unlock();
-		m_callback(index, 0, error_code(ev, get_libtorrent_category()));
+		m_callback(index, address(), 0, error_code(ev, get_libtorrent_category()));
 		l.lock();
 	}
 	else if (m->action == mapping_t::action_add)
 	{
 		l.unlock();
-		m_callback(index, m->external_port, error_code(errors::no_error, get_libtorrent_category()));
+		m_callback(index, m_external_ip, m->external_port,
+			error_code(errors::no_error, get_libtorrent_category()));
 		l.lock();
 	}
 

src/session_impl.cpp

@@ -3608,6 +3608,16 @@ namespace aux {
 		return !m_listen_sockets.empty();
 	}
 
+	address session_impl::listen_address() const
+	{
+		for (std::list<listen_socket_t>::const_iterator i = m_listen_sockets.begin()
+			, end(m_listen_sockets.end()); i != end; ++i)
+		{
+			if (i->external_address != address()) return i->external_address;
+		}
+		return address();
+	}
+
 	unsigned short session_impl::listen_port() const
 	{
 		// if peer connections are set up to be received over a socks
@@ -3667,7 +3677,7 @@ namespace aux {
 			m_alerts.post_alert(portmap_log_alert(map_transport, msg));
 	}
 
-	void session_impl::on_port_mapping(int mapping, int port
+	void session_impl::on_port_mapping(int mapping, address const& ip, int port
 		, error_code const& ec, int map_transport)
 	{
 		TORRENT_ASSERT(is_network_thread());
@@ -3685,8 +3695,12 @@ namespace aux {
 
 		if (mapping == m_tcp_mapping[map_transport] && port != 0)
 		{
-			if (!m_listen_sockets.empty())
+			if (ip != address()) set_external_address(ip);
+
+			if (!m_listen_sockets.empty()) {
+				m_listen_sockets.front().external_address = ip;
 				m_listen_sockets.front().external_port = port;
+			}
 			if (m_alerts.should_post<portmap_alert>())
 				m_alerts.post_alert(portmap_alert(mapping, port
 					, map_transport));
@@ -4248,7 +4262,7 @@ namespace aux {
 		natpmp* n = new (std::nothrow) natpmp(m_io_service
 			, m_listen_interface.address()
 			, boost::bind(&session_impl::on_port_mapping
-				, this, _1, _2, _3, 0)
+				, this, _1, _2, _3, _4, 0)
 			, boost::bind(&session_impl::on_port_map_log
 				, this, _1, 0));
 		if (n == 0) return 0;
@@ -4280,7 +4294,7 @@ namespace aux {
 			, m_listen_interface.address()
 			, m_settings.user_agent
 			, boost::bind(&session_impl::on_port_mapping
-				, this, _1, _2, _3, 1)
+				, this, _1, _2, _3, _4, 1)
 			, boost::bind(&session_impl::on_port_map_log
 				, this, _1, 1)
 			, m_settings.upnp_ignore_nonrouters);

src/upnp.cpp

@@ -960,7 +960,42 @@ void upnp::on_upnp_xml(error_code const& e
 		return;
 	}
 
-	if (num_mappings() > 0) update_map(d, 0, l);
+	d.upnp_connection.reset(new http_connection(m_io_service
+		, m_cc, boost::bind(&upnp::on_upnp_get_ip_address_response, self(), _1, _2
+		, boost::ref(d), _5), true
+		, boost::bind(&upnp::get_ip_address, self(), boost::ref(d))));
+	d.upnp_connection->start(d.hostname, to_string(d.port).elems
+		, seconds(10), 1);
+}
+
+void upnp::get_ip_address(rootdevice& d)
+{
+	mutex::scoped_lock l(m_mutex);
+
+	TORRENT_ASSERT(d.magic == 1337);
+
+	if (!d.upnp_connection)
+	{
+		TORRENT_ASSERT(d.disabled);
+		char msg[200];
+		snprintf(msg, sizeof(msg), "getting external IP address");
+		log(msg, l);
+		return;
+	}
+
+	char const* soap_action = "GetExternalIPAddress";
+
+	char soap[2048];
+	error_code ec;
+	snprintf(soap, sizeof(soap), "<?xml version=\"1.0\"?>\n"
+		"<s:Envelope xmlns:s=\"http://schemas.xmlsoap.org/soap/envelope/\" "
+		"s:encodingStyle=\"http://schemas.xmlsoap.org/soap/encoding/\">"
+		"<s:Body><u:%s xmlns:u=\"%s\">"
+		"</u:%s></s:Body></s:Envelope>"
+		, soap_action, d.service_namespace
+		, soap_action);
+
+	post(d, soap, soap_action, l);
 }
 
 void upnp::disable(error_code const& ec, mutex::scoped_lock& l)
@@ -974,7 +1009,7 @@ void upnp::disable(error_code const& ec, mutex::scoped_lock& l)
 		if (i->protocol == none) continue;
 		i->protocol = none;
 		l.unlock();
-		m_callback(i - m_mappings.begin(), 0, ec);
+		m_callback(i - m_mappings.begin(), address(), 0, ec);
 		l.lock();
 	}
 	
@@ -1012,6 +1047,29 @@ namespace
 		}
 	}
 
+	struct ip_address_parse_state: public error_code_parse_state
+	{
+		ip_address_parse_state(): in_ip_address(false) {}
+		bool in_ip_address;
+		std::string ip_address;
+	};
+
+	void find_ip_address(int type, char const* string, ip_address_parse_state& state)
+	{
+		find_error_code(type, string, state);
+		if (state.exit) return;
+
+		if (type == xml_start_tag && !std::strcmp("NewExternalIPAddress", string))
+		{
+			state.in_ip_address = true;
+		}
+		else if (type == xml_string && state.in_ip_address)
+		{
+			state.ip_address = string;
+			state.exit = true;
+		}
+	}
+
 	struct error_code_t
 	{
 		int code;
@@ -1074,6 +1132,84 @@ namespace libtorrent
 
 #endif
 
+void upnp::on_upnp_get_ip_address_response(error_code const& e
+	, libtorrent::http_parser const& p, rootdevice& d
+	, http_connection& c)
+{
+	boost::intrusive_ptr<upnp> me(self());
+
+	mutex::scoped_lock l(m_mutex);
+
+	TORRENT_ASSERT(d.magic == 1337);
+	if (d.upnp_connection && d.upnp_connection.get() == &c)
+	{
+		d.upnp_connection->close();
+		d.upnp_connection.reset();
+	}
+
+	if (m_closing) return;
+
+	if (e && e != asio::error::eof)
+	{
+		char msg[200];
+		snprintf(msg, sizeof(msg), "error while getting external IP address: %s", e.message().c_str());
+		log(msg, l);
+		if (num_mappings() > 0) update_map(d, 0, l);
+		return;
+	}
+
+	if (!p.header_finished())
+	{
+		log("error while getting external IP address: incomplete http message", l);
+		if (num_mappings() > 0) update_map(d, 0, l);
+		return;
+	}
+
+	if (p.status_code() != 200)
+	{
+		char msg[200];
+		snprintf(msg, sizeof(msg), "error while getting external IP address: %s", p.message().c_str());
+		log(msg, l);
+		if (num_mappings() > 0) update_map(d, 0, l);
+		return;
+	}
+
+	// response may look like
+	// <?xml version="1.0"?>
+	// <s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/" s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
+	// <s:Body><u:GetExternalIPAddressResponse xmlns:u="urn:schemas-upnp-org:service:WANIPConnection:1">
+	// <NewExternalIPAddress>192.168.160.19</NewExternalIPAddress>
+	// </u:GetExternalIPAddressResponse>
+	// </s:Body>
+	// </s:Envelope>
+
+	char msg[500];
+	snprintf(msg, sizeof(msg), "get external IP address response: %s"
+		, std::string(p.get_body().begin, p.get_body().end).c_str());
+	log(msg, l);
+
+	ip_address_parse_state s;
+	xml_parse((char*)p.get_body().begin, (char*)p.get_body().end
+		, boost::bind(&find_ip_address, _1, _2, boost::ref(s)));
+	if (s.error_code != -1)
+	{
+		char msg[200];
+		snprintf(msg, sizeof(msg), "error while getting external IP address, code: %u"
+			, s.error_code);
+		log(msg, l);
+	}
+
+	if (!s.ip_address.empty()) {
+		snprintf(msg, sizeof(msg), "got router external IP address %s", s.ip_address.c_str());
+		log(msg, l);
+		d.external_ip = address::from_string(s.ip_address.c_str(), ec);
+	} else {
+		log("failed to find external IP address in response", l);
+	}
+
+	if (num_mappings() > 0) update_map(d, 0, l);
+}
+
 void upnp::on_upnp_map_response(error_code const& e
 	, libtorrent::http_parser const& p, rootdevice& d, int mapping
 	, http_connection& c)
@@ -1188,7 +1324,7 @@ void upnp::on_upnp_map_response(error_code const& e
 	if (s.error_code == -1)
 	{
 		l.unlock();
-		m_callback(mapping, m.external_port, error_code());
+		m_callback(mapping, d.external_ip, m.external_port, error_code());
 		l.lock();
 		if (d.lease_duration > 0)
 		{
@@ -1231,7 +1367,7 @@ void upnp::return_error(int mapping, int code, mutex::scoped_lock& l)
 		error_string += e->msg;
 	}
 	l.unlock();
-	m_callback(mapping, 0, error_code(code, upnp_category));
+	m_callback(mapping, address(), 0, error_code(code, upnp_category));
 	l.lock();
 }
 

test/test_upnp.cpp

@@ -193,11 +193,11 @@ struct callback_info
 
 std::list<callback_info> callbacks;
 
-void callback(int mapping, int port, error_code const& err)
+void callback(int mapping, address const& ip, int port, error_code const& err)
 {
 	callback_info info = {mapping, port, err};
 	callbacks.push_back(info);
-	std::cerr << "mapping: " << mapping << ", port: " << port
+	std::cerr << "mapping: " << mapping << ", port: " << port << ", IP: " << ip
 		<< ", error: \"" << err.message() << "\"\n";
 	//TODO: store the callbacks and verify that the ports were successful
 }