adjust clock from SSU2

libi2pd/SSU2.cpp

@@ -24,7 +24,7 @@ namespace transport
 		m_AddressV4 (boost::asio::ip::address_v4()), m_AddressV6 (boost::asio::ip::address_v6()),
 		m_TerminationTimer (GetService ()), m_ResendTimer (GetService ()), 
 		m_IntroducersUpdateTimer (GetService ()), m_IntroducersUpdateTimerV6 (GetService ()),
-		m_IsPublished (true)
+		m_IsPublished (true), m_IsSyncClockFromPeers (true)
 	{
 	}
 
@@ -34,6 +34,7 @@ namespace transport
 		{
 			StartIOService ();
 			i2p::config::GetOption ("ssu2.published", m_IsPublished);
+			i2p::config::GetOption("nettime.frompeers", m_IsSyncClockFromPeers);
 			bool found = false;
 			auto& addresses = i2p::context.GetRouterInfo ().GetAddresses ();
 			for (const auto& address: addresses)

libi2pd/SSU2.h

@@ -56,6 +56,7 @@ namespace transport
 			void SetLocalAddress (const boost::asio::ip::address& localAddress);
 			bool IsSupported (const boost::asio::ip::address& addr) const;
 			uint16_t GetPort (bool v4) const;
+			bool IsSyncClockFromPeers () const { return m_IsSyncClockFromPeers; };
 		
 			void AddSession (std::shared_ptr<SSU2Session> session);
 			void RemoveSession (uint64_t connID);
@@ -131,6 +132,7 @@ namespace transport
 				m_IntroducersUpdateTimer, m_IntroducersUpdateTimerV6;
 			std::shared_ptr<SSU2Session> m_LastSession;
 			bool m_IsPublished; // if we maintain introducers
+			bool m_IsSyncClockFromPeers;
 			
 		public:
 

libi2pd/SSU2Session.cpp

@@ -720,6 +720,7 @@ namespace transport
 		}
 		m_NoiseState->MixHash (payload, len - 64); // h = SHA256(h || encrypted payload from SessionCreated) for SessionConfirmed
 		// payload
+		m_State = eSSU2SessionStateSessionCreatedReceived;
 		HandlePayload (decryptedPayload.data (), decryptedPayload.size ());
 
 		m_Server.AddSession (shared_from_this ());
@@ -1320,13 +1321,7 @@ namespace transport
 			{
 				case eSSU2BlkDateTime:
 					LogPrint (eLogDebug, "SSU2: Datetime");
-					if (m_State == eSSU2SessionStateSessionRequestReceived)
-					{
-						auto ts = i2p::util::GetSecondsSinceEpoch ();
-						uint32_t signedOnTime = bufbe32toh (buf + offset);
-						if (signedOnTime < ts - SSU2_CLOCK_SKEW || signedOnTime > ts + SSU2_CLOCK_SKEW)
-							m_TerminationReason = eSSU2TerminationReasonClockSkew;
-					};	
+					HandleDateTime (buf + offset, size);
 				break;
 				case eSSU2BlkOptions:
 					LogPrint (eLogDebug, "SSU2: Options");
@@ -1437,6 +1432,38 @@ namespace transport
 		}
 	}
 
+	void SSU2Session::HandleDateTime (const uint8_t * buf, size_t len)
+	{
+		int64_t offset = (int64_t)i2p::util::GetSecondsSinceEpoch () - (int64_t)bufbe32toh (buf);
+		switch (m_State)
+		{
+			case eSSU2SessionStateSessionRequestReceived:
+				if (std::abs (offset) > SSU2_CLOCK_SKEW)
+					m_TerminationReason = eSSU2TerminationReasonClockSkew;
+			break;
+			case eSSU2SessionStateSessionCreatedReceived:	
+				if ((m_RemoteEndpoint.address ().is_v4 () && i2p::context.GetStatus () == eRouterStatusTesting) ||
+				    (m_RemoteEndpoint.address ().is_v6 () && i2p::context.GetStatusV6 () == eRouterStatusTesting))
+				{
+					if (m_Server.IsSyncClockFromPeers ())
+					{
+						if (std::abs (offset) > SSU2_CLOCK_THRESHOLD)
+						{
+							LogPrint (eLogWarning, "SSU2: Clock adjusted by ", -offset, " seconds");
+							i2p::util::AdjustTimeOffset (-offset);
+						}
+					}
+					else if (std::abs (offset) > SSU2_CLOCK_SKEW)
+					{
+						LogPrint (eLogError, "SSU2: Clock skew detected ", offset, ". Check your clock");
+						i2p::context.SetError (eRouterErrorClockSkew);
+					}
+				}	
+			break;	
+			default: ;	
+		};	
+	}	
+		
 	void SSU2Session::HandleAck (const uint8_t * buf, size_t len)
 	{
 		if (m_State == eSSU2SessionStateSessionConfirmedSent)

libi2pd/SSU2Session.h

@@ -27,6 +27,7 @@ namespace transport
 	const int SSU2_CONNECT_TIMEOUT = 5; // 5 seconds
 	const int SSU2_TERMINATION_TIMEOUT = 330; // 5.5 minutes
 	const int SSU2_CLOCK_SKEW = 60; // in seconds
+	const int SSU2_CLOCK_THRESHOLD = 15; // in seconds, if more we should adjust
 	const int SSU2_TOKEN_EXPIRATION_TIMEOUT = 9; // for Retry message, in seconds
 	const int SSU2_NEXT_TOKEN_EXPIRATION_TIMEOUT = 52*60; // for next token block, in seconds
 	const int SSU2_TOKEN_EXPIRATION_THRESHOLD = 2; // in seconds
@@ -92,6 +93,7 @@ namespace transport
 		eSSU2SessionStateSessionRequestSent,
 		eSSU2SessionStateSessionRequestReceived,
 		eSSU2SessionStateSessionCreatedSent,
+		eSSU2SessionStateSessionCreatedReceived,
 		eSSU2SessionStateSessionConfirmedSent,
 		eSSU2SessionStateEstablished,
 		eSSU2SessionStateClosing,
@@ -280,6 +282,7 @@ namespace transport
 			void SendPathResponse (const uint8_t * data, size_t len);
 			
 			void HandlePayload (const uint8_t * buf, size_t len);
+			void HandleDateTime (const uint8_t * buf, size_t len);
 			void HandleAck (const uint8_t * buf, size_t len);
 			void HandleAckRange (uint32_t firstPacketNum, uint32_t lastPacketNum, uint64_t ts);
 			void HandleAddress (const uint8_t * buf, size_t len);