pick compatible outbound tunnel for datagrams

libi2pd/Datagram.cpp

@@ -371,8 +371,6 @@ namespace datagram
 		{
 			// no current path, make one
 			path = std::make_shared<i2p::garlic::GarlicRoutingPath>();
-			path->outboundTunnel = m_LocalDestination->GetTunnelPool()->GetNextOutboundTunnel();
-			if (!path->outboundTunnel) return nullptr;
 
 			if (m_RemoteLeaseSet)
 			{
@@ -386,6 +384,11 @@ namespace datagram
 				}
 				else
 					return nullptr;
+				
+				auto leaseRouter = i2p::data::netdb.FindRouter (path->remoteLease->tunnelGateway);
+				path->outboundTunnel = m_LocalDestination->GetTunnelPool()->GetNextOutboundTunnel(nullptr,
+					leaseRouter ? leaseRouter->GetCompatibleTransports (false) : (i2p::data::RouterInfo::CompatibleTransports)i2p::data::RouterInfo::eAllTransports);
+				if (!path->outboundTunnel) return nullptr;
 			}
 			else
 			{