don't drop datagram right away if remote LeaseSet is being requested

libi2pd/Datagram.cpp

@@ -749,11 +749,14 @@ namespace datagram
 	void DatagramSession::HandleLeaseSetUpdated(std::shared_ptr<i2p::data::LeaseSet> ls)
 	{
 		m_RequestingLS = false;
-		if(!ls) return;
-		// only update lease set if found and newer than previous lease set
-		uint64_t oldExpire = 0;
-		if(m_RemoteLeaseSet) oldExpire = m_RemoteLeaseSet->GetExpirationTime();
-		if(ls && ls->GetExpirationTime() > oldExpire) m_RemoteLeaseSet = ls;
+		if (ls)
+		{
+			// only update lease set if found and newer than previous lease set
+			uint64_t oldExpire = 0;
+			if(m_RemoteLeaseSet) oldExpire = m_RemoteLeaseSet->GetExpirationTime();
+			if(ls && ls->GetExpirationTime() > oldExpire) m_RemoteLeaseSet = ls;
+		}
+		FlushSendQueue (false); // process deferred flush
 	}
 
 	void DatagramSession::RequestUpdatedLeaseSet ()
@@ -765,10 +768,12 @@ namespace datagram
 		}
 	}
 
-	void DatagramSession::FlushSendQueue ()
+	void DatagramSession::FlushSendQueue (bool waitForLeaseSet)
 	{
 		if (m_SendQueue.empty ()) return;
 		auto routingPath = GetSharedRoutingPath();
+		if (!routingPath && waitForLeaseSet && m_RequestingLS)
+			return; // defer to HandleLeaseSetUpdated
 		// if we don't have a routing path we will drop all queued messages
 		if(routingPath && routingPath->outboundTunnel && routingPath->remoteLease)
 		{

libi2pd/Datagram.h

@@ -73,7 +73,7 @@ namespace datagram
 
 			/** send an i2np message to remote endpoint for this session */
 			void SendMsg(std::shared_ptr<I2NPMessage> msg);
-			void FlushSendQueue();
+			void FlushSendQueue(bool waitForLeaseSet = true);
 			/** get the last time in milliseconds for when we used this datagram session */
 			uint64_t LastActivity() const { return m_LastUse; }