create different I2NP tunnel messages for endpoint and non-endpoint

libi2pd/I2NPProtocol.cpp

@@ -36,11 +36,21 @@ namespace i2p
 		return std::make_shared<I2NPMessageBuffer<I2NP_MAX_SHORT_MESSAGE_SIZE> >();
 	}
 
-	std::shared_ptr<I2NPMessage> NewI2NPTunnelMessage ()
+	std::shared_ptr<I2NPMessage> NewI2NPTunnelMessage (bool endpoint)
 	{
-		// should fit two tunnel message, enough for one garlic encrypted streaming packet
-		auto msg = new I2NPMessageBuffer<2*i2p::tunnel::TUNNEL_DATA_MSG_SIZE + I2NP_HEADER_SIZE + 34>(); // reserved for alignment and NTCP 16 + 6 + 12
+		I2NPMessage * msg = nullptr;
+		if (endpoint)
+		{	
+			// should fit two tunnel message + tunnel gateway header, enough for one garlic encrypted streaming packet
+			msg = new I2NPMessageBuffer<2*i2p::tunnel::TUNNEL_DATA_MSG_SIZE + I2NP_HEADER_SIZE + TUNNEL_GATEWAY_HEADER_SIZE + 28>(); // reserved for alignment and NTCP 16 + 6 + 6
+			msg->Align (6);
+			msg->offset += TUNNEL_GATEWAY_HEADER_SIZE; // reserve room for TunnelGateway header
+		}
+		else
+		{
+			msg = new I2NPMessageBuffer<i2p::tunnel::TUNNEL_DATA_MSG_SIZE + I2NP_HEADER_SIZE + 34>(); // reserved for alignment and NTCP 16 + 6 + 12
 			msg->Align (12);
+		}	
 		return std::shared_ptr<I2NPMessage>(msg);
 	}
 
@@ -692,7 +702,7 @@ namespace i2p
 	
 	std::shared_ptr<I2NPMessage> CreateTunnelDataMsg (const uint8_t * buf)
 	{
-		auto msg = NewI2NPTunnelMessage ();
+		auto msg = NewI2NPTunnelMessage (false);
 		msg->Concat (buf, i2p::tunnel::TUNNEL_DATA_MSG_SIZE);
 		msg->FillI2NPMessageHeader (eI2NPTunnelData);
 		return msg;
@@ -700,7 +710,7 @@ namespace i2p
 
 	std::shared_ptr<I2NPMessage> CreateTunnelDataMsg (uint32_t tunnelID, const uint8_t * payload)
 	{
-		auto msg = NewI2NPTunnelMessage ();
+		auto msg = NewI2NPTunnelMessage (false);
 		htobe32buf (msg->GetPayload (), tunnelID);
 		msg->len += 4; // tunnelID
 		msg->Concat (payload, i2p::tunnel::TUNNEL_DATA_MSG_SIZE - 4);
@@ -708,9 +718,9 @@ namespace i2p
 		return msg;
 	}
 
-	std::shared_ptr<I2NPMessage> CreateEmptyTunnelDataMsg ()
+	std::shared_ptr<I2NPMessage> CreateEmptyTunnelDataMsg (bool endpoint)
 	{
-		auto msg = NewI2NPTunnelMessage ();
+		auto msg = NewI2NPTunnelMessage (endpoint);
 		msg->len += i2p::tunnel::TUNNEL_DATA_MSG_SIZE;
 		return msg;
 	}

libi2pd/I2NPProtocol.h

@@ -278,7 +278,7 @@ namespace tunnel
 
 	std::shared_ptr<I2NPMessage> NewI2NPMessage ();
 	std::shared_ptr<I2NPMessage> NewI2NPShortMessage ();
-	std::shared_ptr<I2NPMessage> NewI2NPTunnelMessage ();
+	std::shared_ptr<I2NPMessage> NewI2NPTunnelMessage (bool endpoint);
 	std::shared_ptr<I2NPMessage> NewI2NPMessage (size_t len);
 
 	std::shared_ptr<I2NPMessage> CreateI2NPMessage (I2NPMessageType msgType, const uint8_t * buf, size_t len, uint32_t replyMsgID = 0);
@@ -307,7 +307,7 @@ namespace tunnel
 
 	std::shared_ptr<I2NPMessage> CreateTunnelDataMsg (const uint8_t * buf);
 	std::shared_ptr<I2NPMessage> CreateTunnelDataMsg (uint32_t tunnelID, const uint8_t * payload);
-	std::shared_ptr<I2NPMessage> CreateEmptyTunnelDataMsg ();
+	std::shared_ptr<I2NPMessage> CreateEmptyTunnelDataMsg (bool endpoint);
 
 	std::shared_ptr<I2NPMessage> CreateTunnelGatewayMsg (uint32_t tunnelID, const uint8_t * buf, size_t len);
 	std::shared_ptr<I2NPMessage> CreateTunnelGatewayMsg (uint32_t tunnelID, I2NPMessageType msgType,

libi2pd/TransitTunnel.cpp

@@ -39,7 +39,7 @@ namespace tunnel
 
 	void TransitTunnelParticipant::HandleTunnelDataMsg (std::shared_ptr<const i2p::I2NPMessage> tunnelMsg)
 	{
-		auto newMsg = CreateEmptyTunnelDataMsg ();
+		auto newMsg = CreateEmptyTunnelDataMsg (false);
 		EncryptTunnelMsg (tunnelMsg, newMsg);
 
 		m_NumTransmittedBytes += tunnelMsg->GetLength ();
@@ -87,7 +87,7 @@ namespace tunnel
 
 	void TransitTunnelEndpoint::HandleTunnelDataMsg (std::shared_ptr<const i2p::I2NPMessage> tunnelMsg)
 	{
-		auto newMsg = CreateEmptyTunnelDataMsg ();
+		auto newMsg = CreateEmptyTunnelDataMsg (true);
 		EncryptTunnelMsg (tunnelMsg, newMsg);
 
 		LogPrint (eLogDebug, "TransitTunnel: handle msg for endpoint ", GetTunnelID ());

libi2pd/Tunnel.cpp

@@ -234,7 +234,7 @@ namespace tunnel
 	void InboundTunnel::HandleTunnelDataMsg (std::shared_ptr<const I2NPMessage> msg)
 	{
 		if (IsFailed ()) SetState (eTunnelStateEstablished); // incoming messages means a tunnel is alive
-		auto newMsg = CreateEmptyTunnelDataMsg ();
+		auto newMsg = CreateEmptyTunnelDataMsg (true);
 		EncryptTunnelMsg (msg, newMsg);
 		newMsg->from = shared_from_this ();
 		m_Endpoint.HandleDecryptedTunnelDataMsg (newMsg);

libi2pd/TunnelEndpoint.cpp

@@ -126,9 +126,7 @@ namespace tunnel
 					if (fragment + size < decrypted + TUNNEL_DATA_ENCRYPTED_SIZE)
 					{
 						// this is not last message. we have to copy it
-						m_CurrentMessage.data = NewI2NPTunnelMessage ();
-						m_CurrentMessage.data->offset += TUNNEL_GATEWAY_HEADER_SIZE; // reserve room for TunnelGateway header
-						m_CurrentMessage.data->len += TUNNEL_GATEWAY_HEADER_SIZE;
+						m_CurrentMessage.data = NewI2NPTunnelMessage (true);
 						*(m_CurrentMessage.data) = *msg;
 					}
 					else

libi2pd/TunnelGateway.cpp

@@ -215,7 +215,7 @@ namespace tunnel
 		const auto& tunnelDataMsgs = m_Buffer.GetTunnelDataMsgs ();
 		for (auto& tunnelMsg : tunnelDataMsgs)
 		{
-			auto newMsg = CreateEmptyTunnelDataMsg ();
+			auto newMsg = CreateEmptyTunnelDataMsg (false);
 			m_Tunnel->EncryptTunnelMsg (tunnelMsg, newMsg);
 			htobe32buf (newMsg->GetPayload (), m_Tunnel->GetNextTunnelID ());
 			newMsg->FillI2NPMessageHeader (eI2NPTunnelData);