send raw datagrams in opposite direction

libi2pd_client/I2PTunnel.cpp

@@ -611,6 +611,7 @@ namespace client
 
 	void I2PUDPServerTunnel::HandleRecvFromI2P(const i2p::data::IdentityEx& from, uint16_t fromPort, uint16_t toPort, const uint8_t * buf, size_t len)
 	{
+		if (!m_LastSession || m_LastSession->Identity.GetLL()[0] != from.GetIdentHash ().GetLL()[0])
 		{
 			std::lock_guard<std::mutex> lock(m_SessionsMutex);
 			m_LastSession = ObtainUDPSession(from, toPort, fromPort);
@@ -658,7 +659,7 @@ namespace client
 		auto ih = from.GetIdentHash();
 		for (auto & s : m_Sessions )
 		{
-			if ( s->Identity == ih)
+			if (s->Identity.GetLL()[0] == ih.GetLL()[0])
 			{
 				/** found existing session */
 				LogPrint(eLogDebug, "UDPServer: found session ", s->IPSocket.local_endpoint(), " ", ih.ToBase32());
@@ -707,11 +708,25 @@ namespace client
 		{
 			LogPrint(eLogDebug, "UDPSession: forward ", len, "B from ", FromEndpoint);
 			LastActivity = i2p::util::GetMillisecondsSinceEpoch();
-			m_Destination->SendDatagramTo(m_Buffer, len, Identity, LocalPort, RemotePort);
+			auto session = m_Destination->GetSession (Identity);
+			m_Destination->SendDatagram(session, m_Buffer, len, LocalPort, RemotePort);
+			size_t numPackets = 0;
+			while (numPackets < i2p::datagram::DATAGRAM_SEND_QUEUE_MAX_SIZE)
+			{	
+				boost::system::error_code ec;
+				size_t moreBytes = IPSocket.available(ec);
+				if (ec || !moreBytes) break;
+				len = IPSocket.receive_from (boost::asio::buffer (m_Buffer, I2P_UDP_MAX_MTU), FromEndpoint, 0, ec);
+				m_Destination->SendRawDatagram (session, m_Buffer, len, LocalPort, RemotePort);			
+				numPackets++;
+			}	
+			if (numPackets > 0)
+				LogPrint(eLogDebug, "UDPSession: forward more ", numPackets, "packets B from ", FromEndpoint);
+			m_Destination->FlushSendQueue (session);
 			Receive();
-		} else {
+		} 
+		else
 			LogPrint(eLogError, "UDPSession: ", ecode.message());
-		}
 	}
 
 	I2PUDPServerTunnel::I2PUDPServerTunnel(const std::string & name, std::shared_ptr<i2p::client::ClientDestination> localDestination,
@@ -781,6 +796,8 @@ namespace client
 			std::placeholders::_1, std::placeholders::_2,
 			std::placeholders::_3, std::placeholders::_4,
 			std::placeholders::_5));
+		dgram->SetRawReceiver(std::bind(&I2PUDPClientTunnel::HandleRecvFromI2PRaw, this,
+			std::placeholders::_1, std::placeholders::_2, std::placeholders::_3, std::placeholders::_4));	
 	}
 
 	void I2PUDPClientTunnel::Start() {
@@ -880,26 +897,30 @@ namespace client
 	void I2PUDPClientTunnel::HandleRecvFromI2P(const i2p::data::IdentityEx& from, uint16_t fromPort, uint16_t toPort, const uint8_t * buf, size_t len)
 	{
 		if(m_RemoteIdent && from.GetIdentHash() == *m_RemoteIdent)
+			HandleRecvFromI2PRaw (fromPort, toPort, buf, len);
+		else
+			LogPrint(eLogWarning, "UDP Client: unwarranted traffic from ", from.GetIdentHash().ToBase32());
+	}
+
+	void I2PUDPClientTunnel::HandleRecvFromI2PRaw(uint16_t fromPort, uint16_t toPort, const uint8_t * buf, size_t len)
+	{
+		auto itr = m_Sessions.find(toPort);
+		// found convo ?
+		if(itr != m_Sessions.end())
 		{
-			auto itr = m_Sessions.find(toPort);
-			// found convo ?
-			if(itr != m_Sessions.end())
+			// found convo
+			if (len > 0) 
 			{
-				// found convo
-				if (len > 0) {
-					LogPrint(eLogDebug, "UDP Client: got ", len, "B from ", from.GetIdentHash().ToBase32());
-					m_LocalSocket.send_to(boost::asio::buffer(buf, len), itr->second->first);
-					// mark convo as active
-					itr->second->second = i2p::util::GetMillisecondsSinceEpoch();
-				}
+				LogPrint(eLogDebug, "UDP Client: got ", len, "B from ", m_RemoteIdent ? m_RemoteIdent->ToBase32() : "");
+				m_LocalSocket.send_to(boost::asio::buffer(buf, len), itr->second->first);
+				// mark convo as active
+				itr->second->second = i2p::util::GetMillisecondsSinceEpoch();
 			}
-			else
-				LogPrint(eLogWarning, "UDP Client: not tracking udp session using port ", (int) toPort);
 		}
 		else
-			LogPrint(eLogWarning, "UDP Client: unwarranted traffic from ", from.GetIdentHash().ToBase32());
+			LogPrint(eLogWarning, "UDP Client: not tracking udp session using port ", (int) toPort);
 	}
-
+		
 	I2PUDPClientTunnel::~I2PUDPClientTunnel() {
 		auto dgram = m_LocalDest->GetDatagramDestination();
 		if (dgram) dgram->ResetReceiver();

libi2pd_client/I2PTunnel.h

@@ -275,7 +275,11 @@ namespace client
 			void RecvFromLocal();
 			void HandleRecvFromLocal(const boost::system::error_code & e, std::size_t transferred);
 			void HandleRecvFromI2P(const i2p::data::IdentityEx& from, uint16_t fromPort, uint16_t toPort, const uint8_t * buf, size_t len);
+			void HandleRecvFromI2PRaw(uint16_t fromPort, uint16_t toPort, const uint8_t * buf, size_t len);
 			void TryResolving();
+
+		private:
+			
 			const std::string m_Name;
 			std::mutex m_SessionsMutex;
 			std::unordered_map<uint16_t, std::shared_ptr<UDPConvo> > m_Sessions; // maps i2p port -> local udp convo