use short tunnel build if possible

libi2pd/NetDb.hpp

@@ -45,6 +45,7 @@ namespace data
 	const int NETDB_MAX_PUBLISH_EXCLUDED_FLOODFILLS = 15; 
 	const int NETDB_MIN_HIGHBANDWIDTH_VERSION = MAKE_VERSION_NUMBER(0, 9, 36); // 0.9.36
 	const int NETDB_MIN_FLOODFILL_VERSION = MAKE_VERSION_NUMBER(0, 9, 38); // 0.9.38
+	const int NETDB_MIN_SHORT_TUNNEL_BUILD_VERSION = MAKE_VERSION_NUMBER(0, 9, 51); // 0.9.51
 
 	/** function for visiting a leaseset stored in a floodfill */
 	typedef std::function<void(const IdentHash, std::shared_ptr<LeaseSet>)> LeaseSetVisitor;

libi2pd/TunnelPool.cpp

@@ -24,6 +24,22 @@ namespace i2p
 {
 namespace tunnel
 {
+	void Path::Add (std::shared_ptr<const i2p::data::RouterInfo> r)
+	{
+		if (r)
+		{	
+			peers.push_back (r->GetRouterIdentity ());
+			if (r->GetVersion () < i2p::data::NETDB_MIN_SHORT_TUNNEL_BUILD_VERSION || 
+			    r->GetRouterIdentity ()->GetCryptoKeyType () != i2p::data::CRYPTO_KEY_TYPE_ECIES_X25519_AEAD)
+				isShort = false;
+		}	
+	}	
+	
+	void Path::Reverse ()
+	{
+		std::reverse (peers.begin (), peers.end ());
+	}	
+	
 	TunnelPool::TunnelPool (int numInboundHops, int numOutboundHops, int numInboundTunnels, int numOutboundTunnels):
 		m_NumInboundHops (numInboundHops), m_NumOutboundHops (numOutboundHops),
 		m_NumInboundTunnels (numInboundTunnels), m_NumOutboundTunnels (numOutboundTunnels),
@@ -420,7 +436,7 @@ namespace tunnel
 		return hop;
 	}
 
-	bool StandardSelectPeers(Path & peers, int numHops, bool inbound, SelectHopFunc nextHop)
+	bool StandardSelectPeers(Path & path, int numHops, bool inbound, SelectHopFunc nextHop)
 	{
 		int start = 0;
 		std::shared_ptr<const i2p::data::RouterInfo> prevHop = i2p::context.GetSharedRouterInfo ();
@@ -429,7 +445,7 @@ namespace tunnel
 			/** if routes are restricted prepend trusted first hop */
 			auto hop = i2p::transport::transports.GetRestrictedPeer();
 			if(!hop) return false;
-			peers.push_back(hop->GetRouterIdentity());
+			path.Add (hop);
 			prevHop = hop;
 			start++;
 		}
@@ -441,7 +457,7 @@ namespace tunnel
 				(numHops > 1 || (r->IsV4 () && (!inbound || r->IsReachable ())))) // first inbound must be reachable
 			{
 				prevHop = r;
-				peers.push_back (r->GetRouterIdentity ());
+				path.Add (r);
 				start++;
 			}
 		}
@@ -466,12 +482,12 @@ namespace tunnel
 				if (hop1) hop = hop1;
 			}	
 			prevHop = hop;
-			peers.push_back (hop->GetRouterIdentity ());
+			path.Add (hop);
 		}
 		return true;
 	}
 
-	bool TunnelPool::SelectPeers (std::vector<std::shared_ptr<const i2p::data::IdentityEx> >& peers, bool isInbound)
+	bool TunnelPool::SelectPeers (Path& path, bool isInbound)
 	{
 		int numHops = isInbound ? m_NumInboundHops : m_NumOutboundHops;
 		// peers is empty
@@ -480,14 +496,14 @@ namespace tunnel
 		{
 			std::lock_guard<std::mutex> lock(m_CustomPeerSelectorMutex);
 			if (m_CustomPeerSelector)
-				return m_CustomPeerSelector->SelectPeers(peers, numHops, isInbound);
+				return m_CustomPeerSelector->SelectPeers(path, numHops, isInbound);
 		}
 		// explicit peers in use
-		if (m_ExplicitPeers) return SelectExplicitPeers (peers, isInbound);
-		return StandardSelectPeers(peers, numHops, isInbound, std::bind(&TunnelPool::SelectNextHop, this, std::placeholders::_1, std::placeholders::_2));
+		if (m_ExplicitPeers) return SelectExplicitPeers (path, isInbound);
+		return StandardSelectPeers(path, numHops, isInbound, std::bind(&TunnelPool::SelectNextHop, this, std::placeholders::_1, std::placeholders::_2));
 	}
 
-	bool TunnelPool::SelectExplicitPeers (std::vector<std::shared_ptr<const i2p::data::IdentityEx> >& peers, bool isInbound)
+	bool TunnelPool::SelectExplicitPeers (Path& path, bool isInbound)
 	{
 		int size = m_ExplicitPeers->size ();
 		std::vector<int> peerIndicies;
@@ -500,7 +516,7 @@ namespace tunnel
 			auto& ident = (*m_ExplicitPeers)[peerIndicies[i]];
 			auto r = i2p::data::netdb.FindRouter (ident);
 			if (r)
-				peers.push_back (r->GetRouterIdentity ());
+				path.Add (r);
 			else
 			{
 				LogPrint (eLogInfo, "Tunnels: Can't find router for ", ident.ToBase64 ());
@@ -517,14 +533,14 @@ namespace tunnel
 		if (!outboundTunnel)
 			outboundTunnel = tunnels.GetNextOutboundTunnel ();
 		LogPrint (eLogDebug, "Tunnels: Creating destination inbound tunnel...");
-		std::vector<std::shared_ptr<const i2p::data::IdentityEx> > peers;
-		if (SelectPeers (peers, true))
+		Path path;
+		if (SelectPeers (path, true))
 		{
 			std::shared_ptr<TunnelConfig> config;
 			if (m_NumInboundHops > 0)
 			{
-				std::reverse (peers.begin (), peers.end ());
-				config = std::make_shared<TunnelConfig> (peers);
+				path.Reverse ();
+				config = std::make_shared<TunnelConfig> (path.peers, path.isShort);
 			}
 			auto tunnel = tunnels.CreateInboundTunnel (config, shared_from_this (), outboundTunnel);
 			if (tunnel->IsEstablished ()) // zero hops
@@ -566,14 +582,23 @@ namespace tunnel
 		if (inboundTunnel)
 		{
 			LogPrint (eLogDebug, "Tunnels: Creating destination outbound tunnel...");
-			std::vector<std::shared_ptr<const i2p::data::IdentityEx> > peers;
-			if (SelectPeers (peers, false))
+			Path path;
+			if (SelectPeers (path, false))
 			{
 				std::shared_ptr<TunnelConfig> config;
 				if (m_NumOutboundHops > 0)
-					config = std::make_shared<TunnelConfig>(peers, inboundTunnel->GetNextTunnelID (), inboundTunnel->GetNextIdentHash ());
-				auto tunnel = tunnels.CreateOutboundTunnel (config, shared_from_this ());
-				if (tunnel->IsEstablished ()) // zero hops
+					config = std::make_shared<TunnelConfig>(path.peers, inboundTunnel->GetNextTunnelID (), inboundTunnel->GetNextIdentHash (), path.isShort);
+
+				std::shared_ptr<OutboundTunnel> tunnel;
+				if (path.isShort)
+				{
+					// TODO: implement it better
+					tunnel = tunnels.CreateOutboundTunnel (config, inboundTunnel->GetTunnelPool ());
+					tunnel->SetTunnelPool (shared_from_this ());
+				}	
+				else	
+					tunnel = tunnels.CreateOutboundTunnel (config, shared_from_this ());
+				if (tunnel && tunnel->IsEstablished ()) // zero hops
 					TunnelCreated (tunnel);
 			}
 			else

libi2pd/TunnelPool.h

@@ -36,7 +36,14 @@ namespace tunnel
 	class OutboundTunnel;
 
 	typedef std::shared_ptr<const i2p::data::IdentityEx> Peer;
-	typedef std::vector<Peer> Path;
+	struct Path
+	{
+		std::vector<Peer> peers;
+		bool isShort = true;
+	
+		void Add (std::shared_ptr<const i2p::data::RouterInfo> r);
+		void Reverse ();
+	};
 
 	/** interface for custom tunnel peer selection algorithm */
 	struct ITunnelPeerSelector
@@ -47,9 +54,8 @@ namespace tunnel
 
 
 	typedef std::function<std::shared_ptr<const i2p::data::RouterInfo>(std::shared_ptr<const i2p::data::RouterInfo>, bool)> SelectHopFunc;
-	// standard peer selection algorithm
-	bool StandardSelectPeers(Path & path, int hops, bool inbound, SelectHopFunc nextHop);
-
+	bool StandardSelectPeers(Path & path, int numHops, bool inbound, SelectHopFunc nextHop);
+	
 	class TunnelPool: public std::enable_shared_from_this<TunnelPool> // per local destination
 	{
 		public:
@@ -114,8 +120,8 @@ namespace tunnel
 			void CreatePairedInboundTunnel (std::shared_ptr<OutboundTunnel> outboundTunnel);
 			template<class TTunnels>
 			typename TTunnels::value_type GetNextTunnel (TTunnels& tunnels, typename TTunnels::value_type excluded) const;
-			bool SelectPeers (std::vector<std::shared_ptr<const i2p::data::IdentityEx> >& hops, bool isInbound);
-			bool SelectExplicitPeers (std::vector<std::shared_ptr<const i2p::data::IdentityEx> >& hops, bool isInbound);
+			bool SelectPeers (Path& path, bool isInbound);
+			bool SelectExplicitPeers (Path& path, bool isInbound);
 
 		private:
 

libi2pd_client/MatchedDestination.cpp

@@ -79,23 +79,23 @@ namespace client
 		if(!inbound && m_RemoteLeaseSet)
 		{
 			if(m_RemoteLeaseSet->IsExpired())
-			{
 				ResolveCurrentLeaseSet();
-			}
 			if(m_RemoteLeaseSet && !m_RemoteLeaseSet->IsExpired())
 			{
 				// remote lease set is good
 				auto leases = m_RemoteLeaseSet->GetNonExpiredLeases();
 				// pick lease
 				std::shared_ptr<i2p::data::RouterInfo> obep;
-				while(!obep && leases.size() > 0) {
+				while(!obep && leases.size() > 0) 
+				{
 					auto idx = rand() % leases.size();
 					auto lease = leases[idx];
 					obep = i2p::data::netdb.FindRouter(lease->tunnelGateway);
 					leases.erase(leases.begin()+idx);
 				}
-				if(obep) {
-					path.push_back(obep->GetRouterIdentity());
+				if(obep) 
+				{
+					path.Add (obep);
 					LogPrint(eLogDebug, "Destination: found OBEP matching IBGW");
 				} else
 					LogPrint(eLogWarning, "Destination: could not find proper IBGW for matched outbound tunnel");