Update Indentation and don't spam route changes in datagram sessions

ClientContext.cpp

@@ -222,7 +222,8 @@ namespace client
 		m_Destinations.clear ();
 		m_SharedLocalDestination = nullptr;
 		// stop io service thread
-    if(m_ServiceThread) {
+		if(m_ServiceThread)
+		{
 			m_Service.stop();
 			m_ServiceThread->join();
 			delete m_ServiceThread;

ClientContext.h

@@ -92,7 +92,6 @@ namespace client
 			std::map<std::pair<i2p::data::IdentHash, int>, std::unique_ptr<I2PServerTunnel> > m_ServerTunnels; // <destination,port>->tunnel
 
 			std::mutex m_ForwardsMutex;			 
-      
 			std::map<boost::asio::ip::udp::endpoint, std::unique_ptr<I2PUDPClientTunnel> > m_ClientForwards; // local endpoint -> udp tunnel
 			std::map<std::pair<i2p::data::IdentHash, int>, std::unique_ptr<I2PUDPServerTunnel> > m_ServerForwards; // <destination,port> -> udp tunnel
 			
@@ -110,6 +109,8 @@ namespace client
 			const decltype(m_Destinations)& GetDestinations () const { return m_Destinations; };
 			const decltype(m_ClientTunnels)& GetClientTunnels () const { return m_ClientTunnels; };
 			const decltype(m_ServerTunnels)& GetServerTunnels () const { return m_ServerTunnels; };
+			const decltype(m_ClientForwards)& GetClientForwards () const { return m_ClientForwards; }
+			const decltype(m_ServerForwards)& GetServerForwards () const { return m_ServerForwards; }
 	};
 	
 	extern ClientContext context;	

Datagram.cpp

@@ -169,7 +169,9 @@ namespace datagram
 		const i2p::data::IdentHash & remoteIdent) :
 		m_LocalDestination(localDestination),
 		m_RemoteIdentity(remoteIdent),
-    m_LastUse(i2p::util::GetMillisecondsSinceEpoch())
+		m_LastUse(i2p::util::GetMillisecondsSinceEpoch ()),
+		m_LastPathChange(0),
+		m_LastSuccess(0)
 	{
 	}
 
@@ -186,16 +188,14 @@ namespace datagram
 		// do we have a routing session?
 		if(m_RoutingSession)
 		{
-      // do we have a routing path ?
-      auto routingPath = m_RoutingSession->GetSharedRoutingPath();
-      if(!routingPath)
+			// should we switch paths?
+			if(ShouldUpdateRoutingPath ())
 			{
 				LogPrint(eLogDebug, "DatagramSession: try getting new routing path");
-        // no routing path, try getting one
-        routingPath = GetNextRoutingPath();
-        if(routingPath) // remember the routing path if we got one
-          m_RoutingSession->SetSharedRoutingPath(routingPath);
+				// try switching paths
+				UpdateRoutingPath (GetNextRoutingPath ());
 			}
+			auto routingPath = m_RoutingSession->GetSharedRoutingPath ();
 			// make sure we have a routing path
 			if (routingPath)
 			{
@@ -204,6 +204,7 @@ namespace datagram
 				{
 					if(outboundTunnel->IsEstablished())
 					{
+						m_LastSuccess = i2p::util::GetMillisecondsSinceEpoch ();
 						// we have a routing path and routing session and the outbound tunnel we are using is good
 						// wrap message with routing session and send down routing path's outbound tunnel wrapped for the IBGW
 						auto m = m_RoutingSession->WrapSingleMessage(msg);
@@ -217,12 +218,49 @@ namespace datagram
 				}
 			}
 		}
-    // we couldn't send so let's try resetting the routing path and updating lease set
-    ResetRoutingPath();
+		auto now = i2p::util::GetMillisecondsSinceEpoch ();
+		// if this path looks dead reset the routing path since we didn't seem to be able to get a path in time
+		if (now - m_LastPathChange >= DATAGRAM_SESSION_PATH_TIMEOUT ) ResetRoutingPath();
 		UpdateLeaseSet(msg);
 		
 	}
 
+	void DatagramSession::UpdateRoutingPath(const std::shared_ptr<i2p::garlic::GarlicRoutingPath> & path)
+	{
+		// we can't update routing path because we have no routing session
+		if(!m_RoutingSession) return;
+		// set routing path and update time we last updated the routing path
+		m_RoutingSession->SetSharedRoutingPath (path);
+		m_LastPathChange = i2p::util::GetMillisecondsSinceEpoch ();
+	}
+
+	bool DatagramSession::ShouldUpdateRoutingPath() const
+	{
+		auto now = i2p::util::GetMillisecondsSinceEpoch ();
+		// we need to rotate paths becuase the routing path is too old
+		if (now - m_LastPathChange >= DATAGRAM_SESSION_PATH_SWITCH_INTERVAL) return true;
+		// our path looks dead so we need to rotate paths
+		if (now - m_LastSuccess >= DATAGRAM_SESSION_PATH_TIMEOUT) return true;
+		// if we have a routing session and routing path we don't need to switch paths
+		return m_RoutingSession != nullptr && m_RoutingSession->GetSharedRoutingPath () != nullptr;
+	}
+
+
+	bool DatagramSession::ShouldSwitchLease() const
+	{
+		auto now = i2p::util::GetMillisecondsSinceEpoch ();
+		std::shared_ptr<i2p::garlic::GarlicRoutingPath> routingPath = nullptr;
+		std::shared_ptr<const i2p::data::Lease> currentLease = nullptr;
+		if(m_RoutingSession)
+			routingPath = m_RoutingSession->GetSharedRoutingPath ();
+		if(routingPath)
+			currentLease = routingPath->remoteLease;
+		if(currentLease) // if we have a lease return true if it's about to expire otherwise return false
+			return now - currentLease->ExpiresWithin( DATAGRAM_SESSION_LEASE_HANDOVER_WINDOW, DATAGRAM_SESSION_LEASE_HANDOVER_FUDGE );
+		// we have no current lease, we should switch
+		return true;
+	}
+	
 	std::shared_ptr<i2p::garlic::GarlicRoutingPath> DatagramSession::GetNextRoutingPath()
 	{
 		std::shared_ptr<i2p::tunnel::OutboundTunnel> outboundTunnel = nullptr;
@@ -241,8 +279,6 @@ namespace datagram
 			}
 			else
 				outboundTunnel = m_LocalDestination->GetTunnelPool()->GetNextOutboundTunnel(routingPath->outboundTunnel); // no so we'll switch outbound tunnels
-      // don't reuse the old path as we are making a new one
-      routingPath = nullptr;
 		}
 		// do we have an outbound tunnel that works already ?
 		if(!outboundTunnel)
@@ -250,8 +286,18 @@ namespace datagram
 
 		if(outboundTunnel)
 		{
-      // get next available lease
-      auto lease = GetNextLease();
+			std::shared_ptr<const i2p::data::Lease> lease = nullptr;
+			// should we switch leases ?
+			if (ShouldSwitchLease ())
+			{
+				// yes, get next available lease
+				lease = GetNextLease();
+			}
+			else if (routingPath)
+			{
+				// stick with the lease we have if we have one
+				lease = routingPath->remoteLease;
+			}
 			if(lease)
 			{
 				// we have a valid lease to use and an outbound tunnel
@@ -265,6 +311,8 @@ namespace datagram
 					0
 				});
 			}
+			else // we don't have a new routing path to give
+				routingPath = nullptr;
 		}
 		return routingPath;
 	}
@@ -283,29 +331,30 @@ namespace datagram
 					m_InvalidIBGW.push_back(routingPath->remoteLease->tunnelGateway); // yes, let's mark remote lease as dead because the outbound tunnel seems fine
 			}
 			// reset the routing path
-      m_RoutingSession->SetSharedRoutingPath(nullptr);
+			UpdateRoutingPath(nullptr);
 		}
 	}
 
 	std::shared_ptr<const i2p::data::Lease> DatagramSession::GetNextLease()
 	{
+		auto now = i2p::util::GetMillisecondsSinceEpoch ();
 		std::shared_ptr<const i2p::data::Lease> next = nullptr;
 		if(m_RemoteLeaseSet)
 		{
 			std::vector<i2p::data::IdentHash> exclude;
 			for(const auto & ident : m_InvalidIBGW)
 				exclude.push_back(ident);
-      // find get all leases that are not in our ban list
-      auto leases = m_RemoteLeaseSet->GetNonExpiredLeasesExcluding( [&exclude] (const i2p::data::Lease & l) -> bool {
+			// find get all leases that are not in our ban list and are not going to expire within our lease set handover window + fudge
+			auto leases = m_RemoteLeaseSet->GetNonExpiredLeasesExcluding( [&exclude, now] (const i2p::data::Lease & l) -> bool {
 				if(exclude.size())
 				{
 					auto end = std::end(exclude);
-          return std::find_if(exclude.begin(), end, [l] ( const i2p::data::IdentHash & ident) -> bool {
-            return ident == l.tunnelGateway;
+					return std::find_if(exclude.begin(), end, [l, now] ( const i2p::data::IdentHash & ident) -> bool {
+							return ident == l.tunnelGateway || l.ExpiresWithin (DATAGRAM_SESSION_LEASE_HANDOVER_WINDOW, DATAGRAM_SESSION_LEASE_HANDOVER_FUDGE);
 					}) != end;
 				}
 				else
-          return false;
+					return l.ExpiresWithin (DATAGRAM_SESSION_LEASE_HANDOVER_WINDOW, DATAGRAM_SESSION_LEASE_HANDOVER_FUDGE);
 			});
 			if(leases.size())
 			{
@@ -325,7 +374,8 @@ namespace datagram
 
 	void DatagramSession::HandleGotLeaseSet(std::shared_ptr<const i2p::data::LeaseSet> remoteIdent, std::shared_ptr<I2NPMessage> msg)
 	{
-    if(remoteIdent) {
+		if(remoteIdent)
+		{
 			// update routing session
 			if(m_RoutingSession)
 				m_RoutingSession = nullptr;

Datagram.h

@@ -22,8 +22,16 @@ namespace datagram
 
 	// seconds interval for cleanup timer
 	const int DATAGRAM_SESSION_CLEANUP_INTERVAL = 3;
-  // milliseconds for max session idle time (10 minutes)
-  const uint64_t DATAGRAM_SESSION_MAX_IDLE = 3600 * 1000;
+	// milliseconds for max session idle time 
+	const uint64_t DATAGRAM_SESSION_MAX_IDLE = 10 * 60 * 1000;
+	// milliseconds for how long we try sticking to a dead routing path before trying to switch
+	const uint64_t DATAGRAM_SESSION_PATH_TIMEOUT = 5000;
+	// milliseconds interval a routing path is used before switching
+	const uint64_t DATAGRAM_SESSION_PATH_SWITCH_INTERVAL = 60 * 1000;
+	// milliseconds before lease expire should we try switching leases
+	const uint64_t DATAGRAM_SESSION_LEASE_HANDOVER_WINDOW = 10 * 1000;
+	// milliseconds fudge factor for leases handover
+	const uint64_t DATAGRAM_SESSION_LEASE_HANDOVER_FUDGE = 1000;
 
 	
 	class DatagramSession
@@ -38,6 +46,15 @@ namespace datagram
 		uint64_t LastActivity() const { return m_LastUse; }
 	private:
 
+		/** update our routing path we are using, mark that we have changed paths */
+		void UpdateRoutingPath(const std::shared_ptr<i2p::garlic::GarlicRoutingPath> & path);
+
+		/** return true if we should switch routing paths because of path lifetime or timeout otherwise false */
+		bool ShouldUpdateRoutingPath() const;
+
+		/** return true if we should switch the lease for out routing path otherwise return false */
+		bool ShouldSwitchLease() const;
+		
 		/** get next usable routing path, try reusing outbound tunnels	*/
 		std::shared_ptr<i2p::garlic::GarlicRoutingPath> GetNextRoutingPath();
 		/** 
@@ -62,6 +79,8 @@ namespace datagram
 		std::vector<i2p::data::IdentHash> m_InvalidIBGW;
 		std::shared_ptr<const i2p::data::LeaseSet> m_RemoteLeaseSet;
 		uint64_t m_LastUse;
+		uint64_t m_LastPathChange;
+		uint64_t m_LastSuccess;
 	};
 	
 	const size_t MAX_DATAGRAM_SIZE = 32768;	 

LeaseSet.cpp

@@ -163,9 +163,10 @@ namespace data
 		return ExtractTimestamp (buf, len) > ExtractTimestamp (m_Buffer, m_BufferLen);
 	}	
 
-	bool LeaseSet::ExpiresSoon(const uint64_t dlt) const
+	bool LeaseSet::ExpiresSoon(const uint64_t dlt, const uint64_t fudge) const
 	{
 		auto now = i2p::util::GetMillisecondsSinceEpoch ();
+		if (fudge) now += rand() % fudge;
 		if (now >= m_ExpirationTime) return true;
 		return	m_ExpirationTime - now <= dlt;
 	}

LeaseSet.h

@@ -7,6 +7,7 @@
 #include <set>
 #include <memory>
 #include "Identity.h"
+#include "Timestamp.h"
 
 namespace i2p
 {
@@ -25,6 +26,12 @@ namespace data
 		uint32_t tunnelID;
 		uint64_t endDate; // 0 means invalid
 		bool isUpdated; // trasient
+		/* return true if this lease expires within t millisecond + fudge factor */
+		bool ExpiresWithin( const uint64_t t, const uint64_t fudge = 1000 ) const {
+			auto expire = i2p::util::GetMillisecondsSinceEpoch ();
+			if(fudge) expire += rand() % fudge;
+			return expire - endDate >= t;
+		}
 	};	
 
 	struct LeaseCmp
@@ -63,7 +70,7 @@ namespace data
 			bool IsExpired () const;
 			bool IsEmpty () const { return m_Leases.empty (); };
 			uint64_t GetExpirationTime () const { return m_ExpirationTime; };
-			bool ExpiresSoon(const uint64_t dlt=1000 * 5) const ;
+			bool ExpiresSoon(const uint64_t dlt=1000 * 5, const uint64_t fudge = 0) const ;
 			bool operator== (const LeaseSet& other) const 
 			{ return m_BufferLen == other.m_BufferLen && !memcmp (m_Buffer, other.m_Buffer, m_BufferLen); };