add latency requirement option

ClientContext.cpp

@@ -372,6 +372,8 @@ namespace client
 		options[I2CP_PARAM_INBOUND_TUNNELS_QUANTITY] = GetI2CPOption (section, I2CP_PARAM_INBOUND_TUNNELS_QUANTITY, DEFAULT_INBOUND_TUNNELS_QUANTITY);
 		options[I2CP_PARAM_OUTBOUND_TUNNELS_QUANTITY] = GetI2CPOption (section, I2CP_PARAM_OUTBOUND_TUNNELS_QUANTITY, DEFAULT_OUTBOUND_TUNNELS_QUANTITY);
 		options[I2CP_PARAM_TAGS_TO_SEND] = GetI2CPOption (section, I2CP_PARAM_TAGS_TO_SEND, DEFAULT_TAGS_TO_SEND);
+		options[I2CP_PARAM_MIN_TUNNEL_LATENCY] = GetI2CPOption(section, I2CP_PARAM_MIN_TUNNEL_LATENCY, DEFAULT_MIN_TUNNEL_LATENCY);
+		options[I2CP_PARAM_MAX_TUNNEL_LATENCY] = GetI2CPOption(section, I2CP_PARAM_MAX_TUNNEL_LATENCY, DEFAULT_MAX_TUNNEL_LATENCY);
 	}	
 
 	void ClientContext::ReadI2CPOptionsFromConfig (const std::string& prefix, std::map<std::string, std::string>& options) const
@@ -384,7 +386,11 @@ namespace client
 		if (i2p::config::GetOption(prefix + I2CP_PARAM_OUTBOUND_TUNNEL_LENGTH, value)) 
 			options[I2CP_PARAM_OUTBOUND_TUNNEL_LENGTH] = value;
 		if (i2p::config::GetOption(prefix + I2CP_PARAM_OUTBOUND_TUNNELS_QUANTITY, value)) 
-			options[I2CP_PARAM_OUTBOUND_TUNNELS_QUANTITY] = value;	
+			options[I2CP_PARAM_OUTBOUND_TUNNELS_QUANTITY] = value;
+		if (i2p::config::GetOption(prefix + I2CP_PARAM_MIN_TUNNEL_LATENCY, value))
+			options[I2CP_PARAM_MIN_TUNNEL_LATENCY] = value;
+		if (i2p::config::GetOption(prefix + I2CP_PARAM_MAX_TUNNEL_LATENCY, value))
+			options[I2CP_PARAM_MAX_TUNNEL_LATENCY] = value;
 	}	
 
 	void ClientContext::ReadTunnels ()

Config.cpp

@@ -86,7 +86,9 @@ namespace config {
 	  ("httpproxy.inbound.length",      value<std::string>()->default_value("3"),  "HTTP proxy inbound tunnel length")	
 	  ("httpproxy.outbound.length",     value<std::string>()->default_value("3"),  "HTTP proxy outbound tunnel length")
 	  ("httpproxy.inbound.quantity",    value<std::string>()->default_value("5"),  "HTTP proxy inbound tunnels quantity")	
-	  ("httpproxy.outbound.quantity",   value<std::string>()->default_value("5"),  "HTTP proxy outbound tunnels quantity")	
+	  ("httpproxy.outbound.quantity",   value<std::string>()->default_value("5"),  "HTTP proxy outbound tunnels quantity")
+			("httpproxy.latency.min",    value<int>()->default_value(0),  "HTTP proxy min latency for tunnels")	
+			("httpproxy.latency.max",   value<int>()->default_value(0),  "HTTP proxy max latency for tunnels")	
       ;
 
     options_description socksproxy("SOCKS Proxy options");
@@ -98,7 +100,9 @@ namespace config {
       ("socksproxy.inbound.length",      value<std::string>()->default_value("3"),  "SOCKS proxy inbound tunnel length")	
 	  ("socksproxy.outbound.length",     value<std::string>()->default_value("3"),  "SOCKS proxy outbound tunnel length")
 	  ("socksproxy.inbound.quantity",    value<std::string>()->default_value("5"),  "SOCKS proxy inbound tunnels quantity")	
-	  ("socksproxy.outbound.quantity",   value<std::string>()->default_value("5"),  "SOCKS proxy outbound tunnels quantity")	
+	  ("socksproxy.outbound.quantity",   value<std::string>()->default_value("5"),  "SOCKS proxy outbound tunnels quantity")
+			("socksproxy.latency.min",    value<int>()->default_value(0),  "SOCKS proxy min latency for tunnels")	
+			("socksproxy.latency.max",   value<int>()->default_value(0),  "SOCKS proxy max latency for tunnels")	
 	  ("socksproxy.outproxy", value<std::string>()->default_value("127.0.0.1"), "Upstream outproxy address for SOCKS Proxy")
       ("socksproxy.outproxyport", value<uint16_t>()->default_value(9050), "Upstream outproxy port for SOCKS Proxy")
       ;

Destination.cpp

@@ -63,6 +63,22 @@ namespace client
 		m_Pool = i2p::tunnel::tunnels.CreateTunnelPool (inLen, outLen, inQty, outQty);
 		if (explicitPeers)
 			m_Pool->SetExplicitPeers (explicitPeers);
+		if(params)
+		{
+			auto itr = params->find(I2CP_PARAM_MAX_TUNNEL_LATENCY);
+			if (itr != params->end()) {
+				auto maxlatency = std::stoi(itr->second);
+				itr = params->find(I2CP_PARAM_MIN_TUNNEL_LATENCY);
+				if (itr != params->end()) {
+					auto minlatency = std::stoi(itr->second);
+					if ( minlatency > 0 && maxlatency > 0 ) {
+						// set tunnel pool latency
+						LogPrint(eLogInfo, "Destination: requiring tunnel latency [", minlatency, "ms, ", maxlatency, "ms]");
+						m_Pool->RequireLatency(minlatency, maxlatency);
+					}
+				}
+			}
+		}
 	}
 
 	LeaseSetDestination::~LeaseSetDestination ()

Destination.h

@@ -50,6 +50,12 @@ namespace client
 	const char I2CP_PARAM_TAGS_TO_SEND[] = "crypto.tagsToSend";
 	const int DEFAULT_TAGS_TO_SEND = 40;
 
+	// latency
+	const char I2CP_PARAM_MIN_TUNNEL_LATENCY[] = "latency.min";
+	const int DEFAULT_MIN_TUNNEL_LATENCY = 0;
+	const char I2CP_PARAM_MAX_TUNNEL_LATENCY[] = "latency.max";
+	const int DEFAULT_MAX_TUNNEL_LATENCY = 0;
+	
 	typedef std::function<void (std::shared_ptr<i2p::stream::Stream> stream)> StreamRequestComplete;
 
 	class LeaseSetDestination: public i2p::garlic::GarlicDestination,

Tunnel.cpp

@@ -21,6 +21,23 @@ namespace i2p
 namespace tunnel
 {
 
+	void TunnelLatency::AddSample(Sample s)
+	{
+		m_samples ++;
+		m_latency += s / m_samples;
+	}
+
+	bool TunnelLatency::HasSamples() const
+	{
+		return m_samples > 0;
+	}
+
+	TunnelLatency::Latency TunnelLatency::GetMeanLatency() const
+	{
+		return m_latency;
+	}
+	
+	
 	Tunnel::Tunnel (std::shared_ptr<const TunnelConfig> config): 
 		TunnelBase (config->GetTunnelID (), config->GetNextTunnelID (), config->GetNextIdentHash ()),
 		m_Config (config), m_Pool (nullptr), m_State (eTunnelStatePending), m_IsRecreated (false)
@@ -162,6 +179,12 @@ namespace tunnel
 		return established;
 	}
 
+	bool Tunnel::LatencyFitsRange(uint64_t lower, uint64_t upper) const
+	{
+		auto latency = GetMeanLatency();
+		return latency >= lower && latency <= upper;
+	}
+	
 	void Tunnel::EncryptTunnelMsg (std::shared_ptr<const I2NPMessage> in, std::shared_ptr<I2NPMessage> out)
 	{
 		const uint8_t * inPayload = in->GetPayload () + 4;

Tunnel.h

@@ -79,6 +79,22 @@ namespace tunnel
 		eTunnelStateExpiring
 	};	
 
+	/** @brief for storing latency history */
+	struct TunnelLatency
+	{
+		typedef uint64_t Sample;
+		typedef uint64_t Latency;
+
+		
+		void AddSample(Sample s);
+		bool HasSamples() const;
+		Latency GetMeanLatency() const;
+
+		Latency m_latency = 0;
+		std::size_t m_samples = 0;
+		
+	};
+	
 	class OutboundTunnel;
 	class InboundTunnel;
 	class Tunnel: public TunnelBase
@@ -118,6 +134,14 @@ namespace tunnel
 			void SendTunnelDataMsg (std::shared_ptr<i2p::I2NPMessage> msg);
 			void EncryptTunnelMsg (std::shared_ptr<const I2NPMessage> in, std::shared_ptr<I2NPMessage> out); 
 
+		/** @brief add latency sample */
+		void AddLatencySample(const uint64_t ms) { m_Latency.AddSample(ms); }
+		/** @brief get this tunnel's estimated latency */
+		uint64_t GetMeanLatency() const { return m_Latency.GetMeanLatency(); }
+		/** @breif return true if this tunnel's latency fits in range [lowerbound, upperbound] */
+		bool LatencyFitsRange(uint64_t lowerbound, uint64_t upperbound) const;
+		
+		bool LatencyIsKnown() const { return m_Latency.HasSamples(); }
 		protected:
 
 			void PrintHops (std::stringstream& s) const;
@@ -129,6 +153,7 @@ namespace tunnel
 			std::shared_ptr<TunnelPool> m_Pool; // pool, tunnel belongs to, or null
 			TunnelState m_State;
 			bool m_IsRecreated;
+		TunnelLatency m_Latency;
 	};	
 
 	class OutboundTunnel: public Tunnel 

TunnelPool.cpp

@@ -147,12 +147,16 @@ namespace tunnel
 
 	std::shared_ptr<OutboundTunnel> TunnelPool::GetNextOutboundTunnel (std::shared_ptr<OutboundTunnel> excluded) const
 	{
-		std::unique_lock<std::mutex> l(m_OutboundTunnelsMutex);	
+		if (HasLatencyRequriement())
+			return GetLowestLatencyOutboundTunnel(excluded);
+		std::unique_lock<std::mutex> l(m_OutboundTunnelsMutex);
 		return GetNextTunnel (m_OutboundTunnels, excluded);
 	}	
 
 	std::shared_ptr<InboundTunnel> TunnelPool::GetNextInboundTunnel (std::shared_ptr<InboundTunnel> excluded) const
 	{
+		if (HasLatencyRequriement())
+			return GetLowestLatencyInboundTunnel(excluded);
 		std::unique_lock<std::mutex> l(m_InboundTunnelsMutex);	
 		return GetNextTunnel (m_InboundTunnels, excluded);
 	}
@@ -322,7 +326,12 @@ namespace tunnel
 				test.first->SetState (eTunnelStateEstablished);
 			if (test.second->GetState () == eTunnelStateTestFailed)
 				test.second->SetState (eTunnelStateEstablished);
-			LogPrint (eLogDebug, "Tunnels: test of ", msgID, " successful. ", i2p::util::GetMillisecondsSinceEpoch () - timestamp, " milliseconds");
+			uint64_t dlt = i2p::util::GetMillisecondsSinceEpoch () - timestamp;
+			LogPrint (eLogDebug, "Tunnels: test of ", msgID, " successful. ", dlt, " milliseconds");
+			// update latency
+			uint64_t latency = dlt / 2;
+			test.first->AddLatencySample(latency);
+			test.second->AddLatencySample(latency);
 		}
 		else
 		{
@@ -523,5 +532,37 @@ namespace tunnel
 		std::lock_guard<std::mutex> lock(m_CustomPeerSelectorMutex);
 		return m_CustomPeerSelector != nullptr;
 	}
+
+	std::shared_ptr<InboundTunnel> TunnelPool::GetLowestLatencyInboundTunnel(std::shared_ptr<InboundTunnel> exclude) const
+	{
+		std::shared_ptr<InboundTunnel> tun = nullptr;
+		std::unique_lock<std::mutex> lock(m_InboundTunnelsMutex);
+		uint64_t min = 1000000;
+		for (const auto & itr : m_InboundTunnels) {
+			if(!itr->LatencyIsKnown()) continue;
+			auto l = itr->GetMeanLatency();
+			if (l >= min) continue;
+			tun = itr;
+			if(tun == exclude) continue;
+			min = l;
+		}
+		return tun;
+	}
+	
+	std::shared_ptr<OutboundTunnel> TunnelPool::GetLowestLatencyOutboundTunnel(std::shared_ptr<OutboundTunnel> exclude) const
+	{
+		std::shared_ptr<OutboundTunnel> tun = nullptr;
+		std::unique_lock<std::mutex> lock(m_OutboundTunnelsMutex);
+		uint64_t min = 1000000;
+		for (const auto & itr : m_OutboundTunnels) {
+			if(!itr->LatencyIsKnown()) continue;
+			auto l = itr->GetMeanLatency();
+			if (l >= min) continue;
+			tun = itr;
+			if(tun == exclude) continue;
+			min = l;
+		}
+		return tun;
+	}
 }
 }

TunnelPool.h

@@ -69,6 +69,17 @@ namespace tunnel
 			void SetCustomPeerSelector(TunnelPeerSelector selector);
 			void UnsetCustomPeerSelector();
 			bool HasCustomPeerSelector();
+
+		/** @brief make this tunnel pool yield tunnels that fit latency range [min, max] */
+		void RequireLatency(uint64_t min, uint64_t max) { m_MinLatency = min; m_MaxLatency = max; }
+
+		/** @brief return true if this tunnel pool has a latency requirement */
+		bool HasLatencyRequriement() const { return m_MinLatency > 0 && m_MaxLatency > 0; }
+
+		/** @brief get the lowest latency tunnel in this tunnel pool regardless of latency requirements */
+		std::shared_ptr<InboundTunnel> GetLowestLatencyInboundTunnel(std::shared_ptr<InboundTunnel> exclude=nullptr) const;
+		std::shared_ptr<OutboundTunnel> GetLowestLatencyOutboundTunnel(std::shared_ptr<OutboundTunnel> exclude=nullptr) const;
+		
 		private:
 			
 			void CreateInboundTunnel ();	
@@ -94,6 +105,10 @@ namespace tunnel
 			bool m_IsActive;
 			std::mutex m_CustomPeerSelectorMutex;
 			TunnelPeerSelector m_CustomPeerSelector;
+
+		uint64_t m_MinLatency=0; // if > 0 this tunnel pool will try building tunnels with minimum latency by ms
+		uint64_t m_MaxLatency=0; // if > 0 this tunnel pool will try building tunnels with maximum latency by ms
+		
 		public:
 
 			// for HTTP only