bypass slow transport sessions

daemon/HTTPServer.cpp

@@ -838,6 +838,7 @@ namespace http {
 					tmp_s << " [itag:" << it->GetRelayTag () << "]";
 				if (it->GetSendQueueSize () > 0)
 					tmp_s << " [queue:" << it->GetSendQueueSize () << "]";
+				if (it->IsSlow ()) tmp_s << " [slow]";
 				tmp_s << "</div>\r\n" << std::endl;
 				cnt++;
 			}

libi2pd/NTCP2.cpp

@@ -452,6 +452,7 @@ namespace transport
 	{
 		m_Establisher->CreateSessionRequestMessage ();
 		// send message
+		m_HandshakeInterval = i2p::util::GetMillisecondsSinceEpoch ();
 		boost::asio::async_write (m_Socket, boost::asio::buffer (m_Establisher->m_SessionRequestBuffer, m_Establisher->m_SessionRequestBufferLen), boost::asio::transfer_all (),
 			std::bind(&NTCP2Session::HandleSessionRequestSent, shared_from_this (), std::placeholders::_1, std::placeholders::_2));
 	}
@@ -529,6 +530,7 @@ namespace transport
 	{
 		m_Establisher->CreateSessionCreatedMessage ();
 		// send message
+		m_HandshakeInterval = i2p::util::GetMillisecondsSinceEpoch ();
 		boost::asio::async_write (m_Socket, boost::asio::buffer (m_Establisher->m_SessionCreatedBuffer, m_Establisher->m_SessionCreatedBufferLen), boost::asio::transfer_all (),
 			std::bind(&NTCP2Session::HandleSessionCreatedSent, shared_from_this (), std::placeholders::_1, std::placeholders::_2));
 	}
@@ -542,6 +544,7 @@ namespace transport
 		}
 		else
 		{
+			m_HandshakeInterval = i2p::util::GetMillisecondsSinceEpoch () - m_HandshakeInterval;
 			LogPrint (eLogDebug, "NTCP2: SessionCreated received ", bytes_transferred);
 			uint16_t paddingLen = 0;
 			if (m_Establisher->ProcessSessionCreatedMessage (paddingLen))
@@ -646,6 +649,7 @@ namespace transport
 		}
 		else
 		{
+			m_HandshakeInterval = i2p::util::GetMillisecondsSinceEpoch () - m_HandshakeInterval;
 			LogPrint (eLogDebug, "NTCP2: SessionConfirmed received");
 			// part 1
 			uint8_t nonce[12];

libi2pd/SSU2Session.cpp

@@ -648,6 +648,7 @@ namespace transport
 		if (m_State == eSSU2SessionStateTokenReceived || m_Server.AddPendingOutgoingSession (shared_from_this ()))
 		{
 			m_State = eSSU2SessionStateSessionRequestSent;
+			m_HandshakeInterval = ts;
 			m_Server.Send (header.buf, 16, headerX, 48, payload, payloadSize, m_RemoteEndpoint);
 		}
 		else
@@ -770,6 +771,7 @@ namespace transport
 		m_State = eSSU2SessionStateSessionCreatedSent;
 		m_SentHandshakePacket->payloadSize = payloadSize;
 		// send
+		m_HandshakeInterval = ts;
 		m_Server.Send (header.buf, 16, headerX, 48, payload, payloadSize, m_RemoteEndpoint);
 	}
 
@@ -790,6 +792,7 @@ namespace transport
 			LogPrint (eLogWarning, "SSU2: SessionCreated message too short ", len);
 			return false;
 		}
+		m_HandshakeInterval = i2p::util::GetMillisecondsSinceEpoch () - m_HandshakeInterval;
 		const uint8_t nonce[12] = {0};
 		uint8_t headerX[48];
 		i2p::crypto::ChaCha20 (buf + 16, 48, kh2, nonce, headerX);
@@ -995,6 +998,7 @@ namespace transport
 			if (m_SessionConfirmedFragment) m_SessionConfirmedFragment.reset (nullptr);
 			return false;
 		}
+		m_HandshakeInterval = i2p::util::GetMillisecondsSinceEpoch () - m_HandshakeInterval;
 		// KDF for Session Confirmed part 1
 		m_NoiseState->MixHash (header.buf, 16); // h = SHA256(h || header)
 		// decrypt part1

libi2pd/TransportSession.h

@@ -69,6 +69,8 @@ namespace transport
 			std::stringstream m_Stream;
 	};
 
+	const int64_t TRANSPORT_SESSION_SLOWNESS_THRESHOLD = 500; // in milliseconds
+	const int64_t TRANSPORT_SESSION_MAX_HANDSHAKE_INTERVAL = 10000; // in milliseconds
 	class TransportSession
 	{
 		public:
@@ -76,7 +78,8 @@ namespace transport
 			TransportSession (std::shared_ptr<const i2p::data::RouterInfo> router, int terminationTimeout):
 				m_NumSentBytes (0), m_NumReceivedBytes (0), m_SendQueueSize (0),
 				m_IsOutgoing (router), m_TerminationTimeout (terminationTimeout),
-				m_LastActivityTimestamp (i2p::util::GetSecondsSinceEpoch ())
+				m_LastActivityTimestamp (i2p::util::GetSecondsSinceEpoch ()),
+				m_HandshakeInterval (0)
 			{
 				if (router)
 					m_RemoteIdentity = router->GetRouterIdentity ();
@@ -103,7 +106,9 @@ namespace transport
 			size_t GetNumReceivedBytes () const { return m_NumReceivedBytes; };
 			size_t GetSendQueueSize () const { return m_SendQueueSize; };
 			bool IsOutgoing () const { return m_IsOutgoing; };
-
+			bool IsSlow () const { return m_HandshakeInterval > TRANSPORT_SESSION_SLOWNESS_THRESHOLD &&
+				m_HandshakeInterval < TRANSPORT_SESSION_MAX_HANDSHAKE_INTERVAL; };
+			
 			int GetTerminationTimeout () const { return m_TerminationTimeout; };
 			void SetTerminationTimeout (int terminationTimeout) { m_TerminationTimeout = terminationTimeout; };
 			bool IsTerminationTimeoutExpired (uint64_t ts) const
@@ -129,6 +134,7 @@ namespace transport
 			int m_TerminationTimeout;
 			uint64_t m_LastActivityTimestamp;
 			uint32_t m_CreationTime; // seconds since epoch
+			int64_t m_HandshakeInterval; // in milliseconds between SessionRequest->SessionCreated or SessionCreated->SessionConfirmed
 	};
 
 	// SOCKS5 proxy

libi2pd/Transports.cpp

@@ -906,9 +906,10 @@ namespace transport
 		return GetRandomPeer (
 			[isHighBandwidth](const Peer& peer)->bool
 			{
-				// connected and not overloaded
+				// connected, not overloaded and not slow
-				return !peer.router && !peer.sessions.empty () &&
+				return !peer.router && !peer.sessions.empty () && peer.isReachable &&
 					peer.sessions.front ()->GetSendQueueSize () <= PEER_ROUTER_INFO_OVERLOAD_QUEUE_SIZE &&
+					!peer.sessions.front ()->IsSlow () &&
 					(!isHighBandwidth || peer.isHighBandwidth);
 			});
 	}

libi2pd/Transports.h

@@ -72,15 +72,18 @@ namespace transport
 		uint64_t creationTime, nextRouterInfoUpdateTime;
 		std::vector<std::shared_ptr<i2p::I2NPMessage> > delayedMessages;
 		std::vector<i2p::data::RouterInfo::SupportedTransports> priority;
-		bool isHighBandwidth;
+		bool isHighBandwidth, isReachable;
 
 		Peer (std::shared_ptr<const i2p::data::RouterInfo> r, uint64_t ts):
 			numAttempts (0), router (r), creationTime (ts),
 			nextRouterInfoUpdateTime (ts + PEER_ROUTER_INFO_UPDATE_INTERVAL),
-			isHighBandwidth (false)
+			isHighBandwidth (false), isReachable (false)
 		{
 			if (router)
+			{		
 				isHighBandwidth = router->IsHighBandwidth ();
+				isReachable = (bool)router->GetCompatibleTransports (true);
+			}	
 		}
 
 		void Done ()
@@ -93,7 +96,10 @@ namespace transport
 		{
 			router = r;
 			if (router)
+			{	
 				isHighBandwidth = router->IsHighBandwidth ();
+				isReachable = (bool)router->GetCompatibleTransports (true);
+			}	
 		}
 	};