add more information to the invalid_request_alert and be more forgiving about requests from peers that have not sent an interested-message first

include/libtorrent/alert_types.hpp

@@ -737,13 +737,26 @@ namespace libtorrent
 		// internal
 		invalid_request_alert(aux::stack_allocator& alloc
 			, torrent_handle const& h, tcp::endpoint const& ep
-			, peer_id const& peer_id, peer_request const& r);
+			, peer_id const& peer_id, peer_request const& r
+			, bool we_have, bool peer_interested, bool withheld);
 
 		TORRENT_DEFINE_ALERT(invalid_request_alert, 25);
 
 		virtual std::string message() const;
 
+		// the request we received from the peer
 		peer_request request;
+
+		// true if we have this piece
+		bool we_have;
+
+		// true if the peer indicated that it was interested to download before
+		// sending the request
+		bool peer_interested;
+
+		// if this is true, the peer is not allowed to download this piece because
+		// of superseeding rules.
+		bool withheld;
 	};
 
 	// This alert is generated when a torrent switches from being a downloader to a seed.

src/alert.cpp

@@ -484,16 +484,26 @@ namespace libtorrent {
 
 	invalid_request_alert::invalid_request_alert(aux::stack_allocator& alloc
 		, torrent_handle const& h, tcp::endpoint const& ep
-		, peer_id const& peer_id, peer_request const& r)
+		, peer_id const& peer_id, peer_request const& r
+		, bool we_have, bool peer_interested, bool withheld)
 		: peer_alert(alloc, h, ep, peer_id)
 		, request(r)
+		, we_have(we_have)
+		, peer_interested(peer_interested)
+		, withheld(withheld)
 	{}
 
 	std::string invalid_request_alert::message() const
 	{
 		char ret[200];
-		snprintf(ret, sizeof(ret), "%s peer sent an invalid piece request (piece: %u start: %u len: %u)"
-			, peer_alert::message().c_str(), request.piece, request.start, request.length);
+		snprintf(ret, sizeof(ret), "%s peer sent an invalid piece request "
+			"(piece: %u start: %u len: %u)%s"
+			, peer_alert::message().c_str(), request.piece, request.start
+			, request.length
+			, withheld ? ": super seeding withheld piece"
+			: !we_have ? ": we don't have piece"
+			: !peer_interested ? ": peer is not interested"
+			: "");
 		return ret;
 	}
 

src/peer_connection.cpp

@@ -2193,7 +2193,8 @@ namespace libtorrent
 			if (t->alerts().should_post<invalid_request_alert>())
 			{
 				t->alerts().emplace_alert<invalid_request_alert>(
-					t->get_handle(), m_remote, m_peer_id, r);
+					t->get_handle(), m_remote, m_peer_id, r
+					, t->has_piece_passed(r.piece), bool(m_peer_interested), true);
 			}
 			return;
 		}
@@ -2248,6 +2249,28 @@ namespace libtorrent
 			, m_accept_fast.end(), r.piece);
 		if (fast_iter != m_accept_fast.end()) fast_idx = fast_iter - m_accept_fast.begin();
 
+		if (!m_peer_interested)
+		{
+#if defined TORRENT_LOGGING
+			peer_log("*** INVALID_REQUEST [ peer is not interested "
+				" t: %d n: %d h: %d block_limit: %d ]"
+				, int(t->torrent_file().piece_size(r.piece))
+				, t->torrent_file().num_pieces()
+				, t->has_piece_passed(r.piece)
+				, t->block_size());
+			peer_log("*** artificial INTERESTED message");
+#endif
+			if (t->alerts().should_post<invalid_request_alert>())
+			{
+				t->alerts().emplace_alert<invalid_request_alert>(
+					t->get_handle(), m_remote, m_peer_id, r
+					, t->has_piece_passed(r.piece), bool(m_peer_interested), false);
+			}
+
+			// be lenient and pretend that the peer said it was interested
+			incoming_interested();
+		}
+
 		// make sure this request
 		// is legal and that the peer
 		// is not choked
@@ -2260,7 +2283,6 @@ namespace libtorrent
 			|| r.start >= t->torrent_file().piece_size(r.piece)
 			|| r.length <= 0
 			|| r.length + r.start > t->torrent_file().piece_size(r.piece)
-			|| !m_peer_interested
 			|| r.length > t->block_size())
 		{
 			m_counters.inc_stats_counter(counters::invalid_piece_requests);
@@ -2284,7 +2306,8 @@ namespace libtorrent
 			if (t->alerts().should_post<invalid_request_alert>())
 			{
 				t->alerts().emplace_alert<invalid_request_alert>(
-					t->get_handle(), m_remote, m_peer_id, r);
+					t->get_handle(), m_remote, m_peer_id, r
+					, t->has_piece_passed(r.piece), bool(m_peer_interested), false);
 			}
 
 			// every ten invalid request, remind the peer that it's choked