fix ip filter exemption for trackers. also add a global setting to always exempt trackers

docs/manual.rst

@@ -4346,6 +4346,7 @@ session_settings
 		int max_metadata_size;
 		bool smooth_connects;
 		bool always_send_user_agent;
+		bool apply_ip_filter_to_trackers;
 	};
 
 ``version`` is automatically set to the libtorrent version you're using
@@ -5191,6 +5192,11 @@ instead of attempting to connectin in batches, and timing them out in batches.
 will include a user-agent with every request, as opposed to just the first
 request in a connection.
 
+``apply_ip_filter_to_trackers`` defaults to true. It determines whether the
+IP filter applies to trackers as well as peers. If this is set to false,
+trackers are exempt from the IP filter (if there is one). If no IP filter
+is set, this setting is irrelevant.
+
 pe_settings
 ===========
 

include/libtorrent/session_settings.hpp

@@ -265,6 +265,7 @@ namespace libtorrent
 			, max_metadata_size(1024*1024)
 			, smooth_connects(true)
 			, always_send_user_agent(false)
+			, apply_ip_filter_to_trackers(true)
 		{}
 
 		// libtorrent version. Used for forward binary compatibility
@@ -1055,6 +1056,10 @@ namespace libtorrent
 
 		// always send user-agent
 		bool always_send_user_agent;
+
+		// if true, trackers will also be filtered by the IP
+		// filter, otherwise they are exempt
+		bool apply_ip_filter_to_trackers;
 	};
 
 #ifndef TORRENT_DISABLE_DHT

include/libtorrent/tracker_manager.hpp

@@ -89,6 +89,7 @@ namespace libtorrent
 			, key(0)
 			, num_want(0)
 			, send_stats(true)
+			, apply_ip_filter(true)
 		{}
 
 		enum
@@ -123,6 +124,7 @@ namespace libtorrent
 		std::string ipv4;
 		address bind_ip;
 		bool send_stats;
+		bool apply_ip_filter;
 	};
 
 	struct TORRENT_EXPORT request_callback

src/http_tracker_connection.cpp

@@ -255,6 +255,8 @@ namespace libtorrent
 
 	void http_tracker_connection::on_filter(http_connection& c, std::list<tcp::endpoint>& endpoints)
 	{
+		if (tracker_req().apply_ip_filter == false) return;
+
 		// remove endpoints that are filtered by the IP filter
 		for (std::list<tcp::endpoint>::iterator i = endpoints.begin();
 			i != endpoints.end();)

src/torrent.cpp

@@ -1868,6 +1868,7 @@ namespace libtorrent
 			e = tracker_request::paused;
 
 		tracker_request req;
+		req.apply_ip_filter = m_apply_ip_filter && m_ses.m_settings.apply_ip_filter_to_trackers;
 		req.info_hash = m_torrent_file->info_hash();
 		req.pid = m_ses.get_peer_id();
 		req.downloaded = m_stat.total_payload_download() - m_total_failed_bytes;
@@ -2027,6 +2028,7 @@ namespace libtorrent
 		if (i == -1) i = 0;
 		
 		tracker_request req;
+		req.apply_ip_filter = m_apply_ip_filter && m_ses.m_settings.apply_ip_filter_to_trackers;
 		req.info_hash = m_torrent_file->info_hash();
 		req.kind = tracker_request::scrape_request;
 		req.url = m_trackers[i].url;

src/udp_tracker_connection.cpp

@@ -163,21 +163,25 @@ namespace libtorrent
 		std::transform(i, tcp::resolver::iterator(), std::back_inserter(m_endpoints)
 			, boost::bind(&tcp::resolver::iterator::value_type::endpoint, _1));
 
-		// remove endpoints that are filtered by the IP filter
+		if (tracker_req().apply_ip_filter)
-		for (std::list<tcp::endpoint>::iterator k = m_endpoints.begin();
-			k != m_endpoints.end();)
 		{
-			if (m_ses.m_ip_filter.access(k->address()) == ip_filter::blocked) 
+			// remove endpoints that are filtered by the IP filter
+			for (std::list<tcp::endpoint>::iterator k = m_endpoints.begin();
+				k != m_endpoints.end();)
 			{
+				if (m_ses.m_ip_filter.access(k->address()) == ip_filter::blocked) 
+				{
 #if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING
-				if (cb) cb->debug_log("*** UDP_TRACKER [ IP blocked by filter: " + print_address(k->address()) + " ]");
+					if (cb) cb->debug_log("*** UDP_TRACKER [ IP blocked by filter: " + print_address(k->address()) + " ]");
 #endif
-				k = m_endpoints.erase(k);
+					k = m_endpoints.erase(k);
+				}
+				else
+					++k;
 			}
-			else
-				++k;
 		}
 
+		// if all endpoints were filtered by the IP filter, we can't connect
 		if (m_endpoints.empty())
 		{
 			fail(error_code(errors::banned_by_ip_filter));