don't send stats to trackers received through tracker exchange

include/libtorrent/torrent_info.hpp

@@ -87,6 +87,7 @@ namespace libtorrent
 			, updating(false)
 			, start_sent(false)
 			, complete_sent(false)
+			, send_stats(true)
 		{}
 
 		std::string url;
@@ -126,6 +127,9 @@ namespace libtorrent
 		// this is true if event completed has been sent to the tracker
 		bool complete_sent:1;
 
+		// this is false the stats sent to this tracker will be 0
+		bool send_stats:1;
+
 		void reset()
 		{
 			start_sent = false;

include/libtorrent/tracker_manager.hpp

@@ -82,6 +82,7 @@ namespace libtorrent
 			, event(none)
 			, key(0)
 			, num_want(0)
+			, send_stats(true)
 		{}
 
 		enum
@@ -111,6 +112,7 @@ namespace libtorrent
 		std::string ipv6;
 		std::string ipv4;
 		address bind_ip;
+		bool send_stats;
 	};
 
 	struct TORRENT_EXPORT request_callback

src/http_tracker_connection.cpp

@@ -137,15 +137,16 @@ namespace libtorrent
 		if (tracker_req().kind == tracker_request::announce_request)
 		{
 			char str[1024];
+			const bool stats = tracker_req().send_stats;
 			snprintf(str, sizeof(str), "&peer_id=%s&port=%d&uploaded=%"PRId64
 				"&downloaded=%"PRId64"&left=%"PRId64"&compact=1&numwant=%d&key=%x&no_peer_id=1"
 				, escape_string((const char*)&tracker_req().pid[0], 20).c_str()
 				// the i2p tracker seems to verify that the port is not 0,
 				// even though it ignores it otherwise
 				, i2p ? 1 : tracker_req().listen_port
-				, tracker_req().uploaded
-				, tracker_req().downloaded
-				, tracker_req().left
+				, stats ? tracker_req().uploaded : 0
+				, stats ? tracker_req().downloaded : 0
+				, stats ? tracker_req().left : 0
 				, tracker_req().num_want
 				, tracker_req().key);
 			url += str;

src/lt_trackers.cpp

@@ -220,6 +220,7 @@ namespace libtorrent { namespace
 				announce_entry e(added->list_string_value_at(i));
 				if (e.url.empty()) continue;
 				e.fail_limit = 3;
+				e.send_stats = false;
 				e.source = announce_entry::source_tex;
 				m_torrent.add_tracker(e);
 #ifdef TORRENT_VERBOSE_LOGGING

src/torrent.cpp

@@ -3606,6 +3606,9 @@ namespace libtorrent
 			for (std::vector<announce_entry>::const_iterator i = m_trackers.begin()
 				, end(m_trackers.end()); i != end; ++i)
 			{
+				// don't save trackers we can't trust
+				// TODO: save the send_stats state instead
+				if (i->send_stats == false) continue;
 				if (i->tier == tier)
 				{
 					tr_list.back().list().push_back(i->url);

src/udp_tracker_connection.cpp

@@ -513,6 +513,7 @@ namespace libtorrent
 		char* out = buf;
 
 		tracker_request const& req = tracker_req();
+		const bool stats = req.send_stats;
 		session_settings const& settings = m_ses.settings();
 
 		detail::write_int64(m_connection_id, out); // connection_id
@@ -522,9 +523,9 @@ namespace libtorrent
 		out += 20;
 		std::copy(req.pid.begin(), req.pid.end(), out); // peer_id
 		out += 20;
-		detail::write_int64(req.downloaded, out); // downloaded
-		detail::write_int64(req.left, out); // left
-		detail::write_int64(req.uploaded, out); // uploaded
+		detail::write_int64(stats ? req.downloaded : 0, out); // downloaded
+		detail::write_int64(stats ? req.left : 0, out); // left
+		detail::write_int64(stats ? req.uploaded : 0, out); // uploaded
 		detail::write_int32(req.event, out); // event
 		// ip address
 		if (settings.announce_ip != address() && settings.announce_ip.is_v4())