don't send expired I2NP messages

libi2pd/I2NPProtocol.cpp

@@ -1,5 +1,5 @@
 /*
-* Copyright (c) 2013-2023, The PurpleI2P Project
+* Copyright (c) 2013-2024, The PurpleI2P Project
 *
 * This file is part of Purple i2pd project and licensed under BSD3
 *
@@ -72,13 +72,17 @@ namespace i2p
 		SetExpiration (i2p::util::GetMillisecondsSinceEpoch () + I2NP_MESSAGE_EXPIRATION_TIMEOUT);
 	}
 
-	bool I2NPMessage::IsExpired () const
+	bool I2NPMessage::IsExpired (uint64_t ts) const
 	{
-		auto ts = i2p::util::GetMillisecondsSinceEpoch ();
 		auto exp = GetExpiration ();
 		return (ts > exp + I2NP_MESSAGE_CLOCK_SKEW) || (ts < exp - 3*I2NP_MESSAGE_CLOCK_SKEW); // check if expired or too far in future
 	}	
 	
+	bool I2NPMessage::IsExpired () const
+	{
+		return IsExpired (i2p::util::GetMillisecondsSinceEpoch ());
+	}
+
 	std::shared_ptr<I2NPMessage> CreateI2NPMessage (I2NPMessageType msgType, const uint8_t * buf, size_t len, uint32_t replyMsgID)
 	{
 		auto msg = NewI2NPMessage (len);

libi2pd/I2NPProtocol.h

@@ -1,5 +1,5 @@
 /*
-* Copyright (c) 2013-2023, The PurpleI2P Project
+* Copyright (c) 2013-2024, The PurpleI2P Project
 *
 * This file is part of Purple i2pd project and licensed under BSD3
 *
@@ -252,6 +252,7 @@ namespace tunnel
 		void FillI2NPMessageHeader (I2NPMessageType msgType, uint32_t replyMsgID = 0, bool checksum = true);
 		void RenewI2NPMessageHeader ();
 		bool IsExpired () const;
+		bool IsExpired (uint64_t ts) const; // in milliseconds
 	};
 
 	template<int sz>

libi2pd/NTCP2.cpp

@@ -1132,10 +1132,17 @@ namespace transport
 		if (!m_SendQueue.empty ())
 		{
 			std::vector<std::shared_ptr<I2NPMessage> > msgs;
+			auto ts = i2p::util::GetMillisecondsSinceEpoch ();
 			size_t s = 0;
 			while (!m_SendQueue.empty ())
 			{
 				auto msg = m_SendQueue.front ();
+				if (!msg || msg->IsExpired (ts))
+				{
+					// drop null or expired message
+					m_SendQueue.pop_front ();
+					continue;
+				}	
 				size_t len = msg->GetNTCP2Length ();
 				if (s + len + 3 <= NTCP2_UNENCRYPTED_FRAME_MAX_SIZE) // 3 bytes block header
 				{

libi2pd/SSU2Session.cpp

@@ -379,8 +379,9 @@ namespace transport
 			while (!m_SendQueue.empty () && m_SentPackets.size () <= m_WindowSize)
 			{
 				auto msg = m_SendQueue.front ();
-				if (!msg)
+				if (!msg || msg->IsExpired (ts))
 				{
+					// drop null or expired message
 					m_SendQueue.pop_front ();
 					continue;
 				}