fix IPv6 tracker support by performing the second announce in more cases

ChangeLog

@@ -1,3 +1,4 @@
+	* fix IPv6 tracker support by performing the second announce in more cases
 	* fix utf-8 encoding check in torrent parser
 	* fix infinite loop when parsing maliciously crafted torrents
 	* fix invalid read in parse_int in bdecoder

include/libtorrent/tracker_manager.hpp

@@ -101,6 +101,7 @@ namespace libtorrent
 			, send_stats(true)
 			, private_torrent(false)
 			, triggered_manually(false)
+			, second_announce(false)
 #ifdef TORRENT_USE_OPENSSL
 			, ssl_ctx(0)
 #endif
@@ -168,6 +169,11 @@ namespace libtorrent
 		// scrape_tracker() or force_reannounce()
 		bool triggered_manually;
 
+		// this is set when announcing to the next address family. There are only
+		// two address families now, so when this is set, we won't trigger another
+		// automatic announce
+		bool second_announce;
+
 #ifdef TORRENT_USE_OPENSSL
 		boost::asio::ssl::context* ssl_ctx;
 #endif

simulation/test_tracker.cpp

@@ -287,9 +287,8 @@ void on_alert_notify(lt::session* ses)
 	});
 }
 
-// this test makes sure that a tracker whose host name resolves to both IPv6 and
-// IPv4 addresses will be announced to twice, once for each address family
-TORRENT_TEST(ipv6_support)
+void test_ipv6_support(char const* listen_interfaces
+	, int const expect_v4, int const expect_v6)
 {
 	using sim::asio::ip::address_v4;
 	sim_config network_cfg;
@@ -335,6 +334,7 @@ TORRENT_TEST(ipv6_support)
 		asio::io_service ios(sim, { address_v4::from_string("10.0.0.3")
 			, address_v6::from_string("ffff::1337") });
 		lt::settings_pack sett = settings();
+		sett.set_str(settings_pack::listen_interfaces, listen_interfaces);
 		std::unique_ptr<lt::session> ses(new lt::session(sett, ios));
 
 		ses->set_alert_notify(std::bind(&on_alert_notify, ses.get()));
@@ -370,9 +370,46 @@ TORRENT_TEST(ipv6_support)
 		sim.run();
 	}
 
+	TEST_EQUAL(v4_announces, expect_v4);
+	TEST_EQUAL(v6_announces, expect_v6);
+}
+
+// this test makes sure that a tracker whose host name resolves to both IPv6 and
+// IPv4 addresses will be announced to twice, once for each address family
+TORRENT_TEST(ipv6_support)
+{
 	// 2 because there's one announce on startup and one when shutting down
-	TEST_EQUAL(v4_announces, 2);
-	TEST_EQUAL(v6_announces, 2);
+	test_ipv6_support("0.0.0.0:6881", 2, 2);
+}
+
+TORRENT_TEST(ipv6_support_bind_v4_v6_any)
+{
+	test_ipv6_support("0.0.0.0:6881,[::0]:6881", 2, 2);
+}
+
+TORRENT_TEST(ipv6_support_bind_v6_any)
+{
+	test_ipv6_support("[::0]:6881", 0, 2);
+}
+
+TORRENT_TEST(ipv6_support_bind_v4)
+{
+	test_ipv6_support("10.0.0.3:6881", 2, 0);
+}
+
+TORRENT_TEST(ipv6_support_bind_v6)
+{
+	test_ipv6_support("[ffff::1337]:6881", 0, 2);
+}
+
+TORRENT_TEST(ipv6_support_bind_v4_v6)
+{
+	test_ipv6_support("10.0.0.3:6881,[ffff::1337]:6881", 2, 2);
+}
+
+TORRENT_TEST(ipv6_support_bind_v6_v4)
+{
+	test_ipv6_support("[ffff::1337]:6881,10.0.0.3:6881", 2, 2);
 }
 
 // this runs a simulation of a torrent with tracker(s), making sure the request

src/torrent.cpp

@@ -3641,15 +3641,12 @@ namespace {
 		// when talking to the tracker. If there is a matching interface
 		// type in the tracker IP list, make another tracker request
 		// using that interface
-		// in order to avoid triggering this case over and over, don't
-		// do it if the bind IP for the tracker request that just completed
-		// matches one of the listen interfaces, since that means this
-		// announce was the second one
+		// in order to avoid triggering this case over and over, check whether
+		// this announce was itself triggered by this logic (second_announce)
 
 		if (((!is_any(m_ses.get_ipv6_interface().address()) && tracker_ip.is_v4())
 			|| (!is_any(m_ses.get_ipv4_interface().address()) && tracker_ip.is_v6()))
-			&& r.bind_ip != m_ses.get_ipv4_interface().address()
-			&& r.bind_ip != m_ses.get_ipv6_interface().address())
+			&& !r.second_announce)
 		{
 			std::list<address>::const_iterator i = std::find_if(tracker_ips.begin()
 				, tracker_ips.end(), boost::bind(&address::is_v4, _1) != tracker_ip.is_v4());
@@ -3667,6 +3664,7 @@ namespace {
 				tracker_request req = r;
 
 				req.private_torrent = m_torrent_file->priv();
+				req.second_announce = true;
 
 				// tell the tracker to bind to the opposite protocol type
 				req.bind_ip = tracker_ip.is_v4()