cleanup received messages list by timestamp

libi2pd/SSUData.cpp

@@ -246,8 +246,8 @@ namespace transport
 				{
 					if (!m_ReceivedMessages.count (msgID))
 					{
-						m_ReceivedMessages.insert (msgID);
 						m_LastMessageReceivedTime = i2p::util::GetSecondsSinceEpoch ();
+						m_ReceivedMessages.emplace (msgID, m_LastMessageReceivedTime);
 						if (!msg->IsExpired ())
 						{
 							m_Handler.PutNextMessage (msg);
@@ -511,10 +511,21 @@ namespace transport
 				else
 					++it;
 			}
-			// decay
+		
-			if (m_ReceivedMessages.size () > MAX_NUM_RECEIVED_MESSAGES ||
+			if (m_ReceivedMessages.size () > MAX_NUM_RECEIVED_MESSAGES || ts > m_LastMessageReceivedTime + DECAY_INTERVAL)
-				i2p::util::GetSecondsSinceEpoch () > m_LastMessageReceivedTime + DECAY_INTERVAL)
+				// decay
 				m_ReceivedMessages.clear ();
+			else
+			{
+				// delete old received messages	
+				for (auto it = m_ReceivedMessages.begin (); it != m_ReceivedMessages.end ();)
+				{
+					if (ts > it->second + RECEIVED_MESSAGES_CLEANUP_TIMEOUT)
+						it = m_ReceivedMessages.erase (it);
+					else
+						++it;
+				}		
+			}		
 
 			ScheduleIncompleteMessagesCleanup ();
 		}

libi2pd/SSUData.h

@@ -40,6 +40,7 @@ namespace transport
 	const int MAX_NUM_RESENDS = 5;
 	const int DECAY_INTERVAL = 20; // in seconds
 	const int INCOMPLETE_MESSAGES_CLEANUP_TIMEOUT = 30; // in seconds
+	const int RECEIVED_MESSAGES_CLEANUP_TIMEOUT = 40; // in seconds
 	const unsigned int MAX_NUM_RECEIVED_MESSAGES = 1000; // how many msgID we store for duplicates check
 	const int MAX_OUTGOING_WINDOW_SIZE = 200; // how many unacked message we can store
 	// data flags
@@ -128,7 +129,7 @@ namespace transport
 			SSUSession& m_Session;
 			std::unordered_map<uint32_t, std::shared_ptr<IncompleteMessage> > m_IncompleteMessages;
 			std::unordered_map<uint32_t, std::shared_ptr<SentMessage> > m_SentMessages;
-			std::unordered_set<uint32_t> m_ReceivedMessages;
+			std::unordered_map<uint32_t, uint64_t> m_ReceivedMessages; // msgID -> timestamp in seconds
 			boost::asio::deadline_timer m_ResendTimer, m_IncompleteMessagesCleanupTimer;
 			int m_MaxPacketSize, m_PacketSize;
 			i2p::I2NPMessagesHandler m_Handler;