send termiation with reason

libi2pd/SSU2.cpp

@@ -148,7 +148,7 @@ namespace transport
 	void SSU2Server::Receive (boost::asio::ip::udp::socket& socket)
 	{
 		Packet * packet = m_PacketsPool.AcquireMt ();
-		socket.async_receive_from (boost::asio::buffer (packet->buf, SSU2_MTU), packet->from,
+		socket.async_receive_from (boost::asio::buffer (packet->buf, SSU2_MAX_PACKET_SIZE), packet->from,
 			std::bind (&SSU2Server::HandleReceivedFrom, this, std::placeholders::_1, std::placeholders::_2, packet, std::ref (socket)));
 	}
 
@@ -388,7 +388,7 @@ namespace transport
 					m_LastSession->ProcessPeerTest (buf, len);
 				break;
 				case eSSU2SessionStateClosing:
-					m_LastSession->RequestTermination (); // send termination again
+					m_LastSession->RequestTermination (eSSU2TerminationReasonIdleTimeout); // send termination again
 				break;	
 				case eSSU2SessionStateTerminated:
 					m_LastSession = nullptr;
@@ -630,7 +630,7 @@ namespace transport
 				else if (it.second->IsTerminationTimeoutExpired (ts))
 				{
 					if (it.second->IsEstablished ())
-						it.second->RequestTermination ();
+						it.second->RequestTermination (eSSU2TerminationReasonIdleTimeout);
 					else
 						GetService ().post (std::bind (&SSU2Session::Terminate, it.second));
 				}

libi2pd/SSU2.h

@@ -25,7 +25,7 @@ namespace transport
 	{
 		struct Packet
 		{
-			uint8_t buf[SSU2_MTU];
+			uint8_t buf[SSU2_MAX_PACKET_SIZE];
 			size_t len;
 			boost::asio::ip::udp::endpoint from;
 		};

libi2pd/SSU2Session.cpp

@@ -25,7 +25,7 @@ namespace transport
 		m_DestConnID (0), m_SourceConnID (0), m_State (eSSU2SessionStateUnknown),
 		m_SendPacketNum (0), m_ReceivePacketNum (0), m_IsDataReceived (false), 
 		m_WindowSize (SSU2_MAX_WINDOW_SIZE), m_RelayTag (0), 
-		m_ConnectTimer (server.GetService ())
+		m_ConnectTimer (server.GetService ()), m_TerminationReason (eSSU2TerminationReasonNormalClose)
 	{
 		m_NoiseState.reset (new i2p::crypto::NoiseSymmetricState);
 		if (in_RemoteRouter && m_Address)
@@ -168,11 +168,12 @@ namespace transport
 		}
 	}
 
-	void SSU2Session::RequestTermination ()
+	void SSU2Session::RequestTermination (SSU2TerminationReason reason)
 	{
 		if (m_State == eSSU2SessionStateEstablished || m_State == eSSU2SessionStateClosing)
 		{
 			m_State = eSSU2SessionStateClosing;
+			m_TerminationReason = reason;
 			SendTermination ();
 		}	
 	}	
@@ -329,7 +330,7 @@ namespace transport
 					LogPrint (eLogInfo, "SSU2: Packet was not Acked after ", it->second->numResends, " attempts. Terminate session");
 					m_SentPackets.clear ();
 					m_SendQueue.clear ();
-					RequestTermination ();
+					RequestTermination (eSSU2TerminationReasonTimeout);
 					return;
 				}	
 				else
@@ -2097,6 +2098,15 @@ namespace transport
 		return CreatePeerTestBlock (buf, len, 1, eSSU2PeerTestCodeAccept, nullptr, 
 			signedData, 10 + asz + i2p::context.GetIdentity ()->GetSignatureLen ());
 	}	
+
+	size_t SSU2Session::CreateTerminationBlock (uint8_t * buf, size_t len)
+	{   
+		buf[0] = eSSU2BlkTermination;
+		htobe16buf (buf + 1, 9);
+		htobe64buf (buf + 3, m_ReceivePacketNum);
+		buf[11] = (uint8_t)m_TerminationReason;
+		return 12;
+	}
 		
 	std::shared_ptr<const i2p::data::RouterInfo> SSU2Session::ExtractRouterInfo (const uint8_t * buf, size_t size)
 	{
@@ -2157,10 +2167,7 @@ namespace transport
 	void SSU2Session::SendTermination ()
 	{
 		uint8_t payload[32];
-		size_t payloadSize = 12;
-		payload[0] = eSSU2BlkTermination;
-		htobe16buf (payload + 1, 9);
-		memset (payload + 3, 0, 9);
+		size_t payloadSize = CreateTerminationBlock (payload, 32);
 		payloadSize += CreatePaddingBlock (payload + payloadSize, 32 - payloadSize);
 		SendData (payload, payloadSize);
 	}

libi2pd/SSU2Session.h

@@ -31,6 +31,7 @@ namespace transport
 	const int SSU2_TOKEN_EXPIRATION_THRESHOLD = 2; // in seconds
 	const int SSU2_RELAY_NONCE_EXPIRATION_TIMEOUT = 10; // in seconds
 	const int SSU2_PEER_TEST_EXPIRATION_TIMEOUT = 60; // 60 seconds
+	const size_t SSU2_MAX_PACKET_SIZE = 1500;
 	const size_t SSU2_MTU = 1440; // TODO: should be 1456 for ipv4
 	const size_t SSU2_MAX_PAYLOAD_SIZE = SSU2_MTU - 32;
 	const int SSU2_HANDSHAKE_RESEND_INTERVAL = 1; // in seconds
@@ -119,6 +120,32 @@ namespace transport
 		eSSU2RelayResponseCodeCharlieSignatureFailure = 67,
 		eSSU2RelayResponseCodeCharlieAliceIsUnknown = 70
 	};	
+
+	enum SSU2TerminationReason
+	{
+		eSSU2TerminationReasonNormalClose = 0,
+		eSSU2TerminationReasonTerminationReceived = 1,
+		eSSU2TerminationReasonIdleTimeout = 2,
+		eSSU2TerminationReasonRouterShutdown = 3,
+		eSSU2TerminationReasonDataPhaseAEADFailure= 4,
+		eSSU2TerminationReasonIncompatibleOptions = 5,
+		eSSU2TerminationReasonTncompatibleSignatureType = 6,
+		eSSU2TerminationReasonClockSkew = 7,
+		eSSU2TerminationPaddingViolation = 8,
+		eSSU2TerminationReasonAEADFramingError = 9,
+		eSSU2TerminationReasonPayloadFormatError = 10,
+		eSSU2TerminationReasonSessionRequestError = 11,
+		eSSU2TerminationReasonSessionCreatedError = 12,
+		eSSU2TerminationReasonSessionConfirmedError = 13,
+		eSSU2TerminationReasonTimeout = 14,
+		eSSU2TerminationReasonRouterInfoSignatureVerificationFail = 15,
+		eSSU2TerminationReasonInvalidS = 16,
+		eSSU2TerminationReasonBanned = 17,
+		eSSU2TerminationReasonBadToken = 18,
+		eSSU2TerminationReasonConnectionLimits = 19,
+		eSSU2TerminationReasonIncompatibleVersion = 20,
+		eSSU2TerminationReasonWrongNetID = 21
+	};	
 	
 	struct SSU2IncompleteMessage
 	{
@@ -189,7 +216,7 @@ namespace transport
 			void WaitForIntroduction ();
 			void SendPeerTest (); // Alice, Data message
 			void Terminate ();
-			void RequestTermination ();
+			void RequestTermination (SSU2TerminationReason reason);
 			void CleanUp (uint64_t ts);
 			void FlushData ();
 			void Done () override;
@@ -264,6 +291,7 @@ namespace transport
 			size_t CreateRelayResponseBlock (uint8_t * buf, size_t len, SSU2RelayResponseCode code, uint32_t nonce, bool endpoint, uint64_t token); // add endpoint for Chralie and no endpoint for Bob
 			size_t CreatePeerTestBlock (uint8_t * buf, size_t len, uint8_t msg, SSU2PeerTestCode code, const uint8_t * routerHash, const uint8_t * signedData, size_t signedDataLen);
 			size_t CreatePeerTestBlock (uint8_t * buf, size_t len, uint32_t nonce); // Alice
+			size_t CreateTerminationBlock (uint8_t * buf, size_t len);
 
 		private:
 
@@ -291,6 +319,7 @@ namespace transport
 			uint32_t m_RelayTag; // between Bob and Charlie
 			OnEstablished m_OnEstablished; // callback from Established
 			boost::asio::deadline_timer m_ConnectTimer;
+			SSU2TerminationReason m_TerminationReason;
 	};
 
 	inline uint64_t CreateHeaderMask (const uint8_t * kh, const uint8_t * nonce)