don't use expired introducer even if we a session with it

libi2pd/SSU2.cpp

@@ -775,8 +775,12 @@ namespace transport
 		auto address = session->GetAddress ();
 		if (!address) return;
 		session->WaitForIntroduction ();
+		auto ts = i2p::util::GetSecondsSinceEpoch ();
+		std::vector<int> indices; int i = 0;
 		// try to find existing session first
 		for (auto& it: address->ssu->introducers)
+		{
+			if (it.iTag && ts < it.iExp)
 			{
 				auto it1 = m_SessionsByRouterHash.find (it.iH);
 				if (it1 != m_SessionsByRouterHash.end ())
@@ -784,23 +788,23 @@ namespace transport
 					it1->second->Introduce (session, it.iTag);
 					return;
 				}
+				else
+					indices.push_back(i);
+			}	
+			i++;
 		}
 		// we have to start a new session to an introducer
-		auto ts = i2p::util::GetSecondsSinceEpoch ();
 		std::shared_ptr<i2p::data::RouterInfo> r;
 		uint32_t relayTag = 0;
-		if (!address->ssu->introducers.empty ())
+		if (!indices.empty ())
 		{
-			std::vector<int> indices;
-			for (int i = 0; i < (int)address->ssu->introducers.size (); i++) indices.push_back(i);
 			if (indices.size () > 1)
-				std::shuffle (indices.begin(), indices.end(), std::mt19937(std::random_device()()));
+				std::shuffle (indices.begin(), indices.end(), std::mt19937(ts));
 
 			for (auto i: indices)
 			{
 				const auto& introducer = address->ssu->introducers[indices[i]];
-				if (introducer.iTag && ts < introducer.iExp)
-				{
+				// introducer is not expired, because in indices
 				r = i2p::data::netdb.FindRouter (introducer.iH);
 				if (r && r->IsReachableFrom (i2p::context.GetRouterInfo ()))
 				{
@@ -809,7 +813,6 @@ namespace transport
 				}
 			}
 		}
-		}
 		if (r)
 		{
 			if (relayTag)