use min hole punch interval for connection attempts

libi2pd/SSU2.cpp

@@ -216,16 +216,16 @@ namespace transport
 		return ep.port ();
 	}
 
-	bool SSU2Server::IsConnectedRecently (const boost::asio::ip::udp::endpoint& ep)
+	bool SSU2Server::IsConnectedRecently (const boost::asio::ip::udp::endpoint& ep, bool max)
 	{
 		if (!ep.port () || ep.address ().is_unspecified ()) return false;
 		std::lock_guard<std::mutex> l(m_ConnectedRecentlyMutex);
 		auto it = m_ConnectedRecently.find (ep);
 		if (it != m_ConnectedRecently.end ())
 		{	
-			if (i2p::util::GetSecondsSinceEpoch () <= it->second + SSU2_HOLE_PUNCH_EXPIRATION)
+			if (i2p::util::GetSecondsSinceEpoch () <= it->second + (max ? SSU2_MAX_HOLE_PUNCH_EXPIRATION : SSU2_MIN_HOLE_PUNCH_EXPIRATION))
 				return true;
-			else
+			else if (max)
 				m_ConnectedRecently.erase (it);
 		}	
 		return false;
@@ -234,7 +234,7 @@ namespace transport
 	void SSU2Server::AddConnectedRecently (const boost::asio::ip::udp::endpoint& ep, uint64_t ts)
 	{
 		if (!ep.port () || ep.address ().is_unspecified () || 
-		    i2p::util::GetSecondsSinceEpoch () > ts + SSU2_HOLE_PUNCH_EXPIRATION) return;
+		    i2p::util::GetSecondsSinceEpoch () > ts + SSU2_MAX_HOLE_PUNCH_EXPIRATION) return;
 		std::lock_guard<std::mutex> l(m_ConnectedRecentlyMutex);
 		auto [it, added] = m_ConnectedRecently.try_emplace (ep, ts);
 		if (!added && ts > it->second)
@@ -885,7 +885,7 @@ namespace transport
 			{
 				// router doesn't publish endpoint, but we connected before and hole punch might be alive
 				auto ep = router->GetProfile ()->GetLastEndpoint ();
-				if (IsConnectedRecently (ep))
+				if (IsConnectedRecently (ep, false))
 				{
 					if (CheckPendingOutgoingSession (ep, peerTest)) return false;
 					session->SetRemoteEndpoint (ep);
@@ -1148,7 +1148,7 @@ namespace transport
 
 			for (auto it = m_ConnectedRecently.begin (); it != m_ConnectedRecently.end (); )
 			{
-				if (ts > it->second + SSU2_HOLE_PUNCH_EXPIRATION)
+				if (ts > it->second + SSU2_MAX_HOLE_PUNCH_EXPIRATION)
 					it = m_ConnectedRecently.erase (it);
 				else
 					it++;

libi2pd/SSU2.h

@@ -42,7 +42,8 @@ namespace transport
 	const int SSU2_KEEP_ALIVE_INTERVAL = 15; // in seconds
 	const int SSU2_KEEP_ALIVE_INTERVAL_VARIANCE = 4; // in seconds
 	const int SSU2_PROXY_CONNECT_RETRY_TIMEOUT = 30; // in seconds
-	const int SSU2_HOLE_PUNCH_EXPIRATION = 150; // in seconds
+	const int SSU2_MIN_HOLE_PUNCH_EXPIRATION = 45; // in seconds
+	const int SSU2_MAX_HOLE_PUNCH_EXPIRATION = 181; // in seconds
 	const size_t SSU2_MAX_NUM_PACKETS_PER_BATCH = 64;
 
 	class SSU2Server: private i2p::util::RunnableServiceWithWork
@@ -77,7 +78,7 @@ namespace transport
 			bool UsesProxy () const { return m_IsThroughProxy; };
 			bool IsSupported (const boost::asio::ip::address& addr) const;
 			uint16_t GetPort (bool v4) const;
-			bool IsConnectedRecently (const boost::asio::ip::udp::endpoint& ep);
+			bool IsConnectedRecently (const boost::asio::ip::udp::endpoint& ep, bool max = true);
 			void AddConnectedRecently (const boost::asio::ip::udp::endpoint& ep, uint64_t ts);
 			std::mt19937& GetRng () { return m_Rng; }
 			bool IsMaxNumIntroducers (bool v4) const { return (v4 ? m_Introducers.size () : m_IntroducersV6.size ()) >= SSU2_MAX_NUM_INTRODUCERS; }

libi2pd/Transports.cpp

@@ -685,7 +685,7 @@ namespace transport
 					if (ep.address ().is_v4 ())
 					{	
 						if ((supportedTransports & i2p::data::RouterInfo::eSSU2V4) &&
-							m_SSU2Server->IsConnectedRecently (ep))
+							m_SSU2Server->IsConnectedRecently (ep, false))
 							peer->priority.push_back (i2p::data::RouterInfo::eSSU2V4);
 					}	
 					else if (ep.address ().is_v6 ())