PHYPayload Unmarshalling -> uplink about lorawan

[brocaar]

Thanks again for your input :-)

There are a couple of things that are depending on the direction of the payload: calculation of MIC, MAC commands (uplink and downlink share the same bits in the CID field), encryption and frame counters. So without knowing if it's uplink or downlink, there is no way to decode and validate a payload correctly.

It is possible to guess the direction by looking at the MType field. This will work in most cases, except for MType=Proprietary, so this is not a solid solution.

So I think there is no way to know for sure if the payload is uplink or downlink by looking at the byte slice, unfortunately.