Relay WFCnt periodic retrieval

[adriansmares]

Summary

The Network Server can retrieve the WFCnt from the relay periodically in order to persist it between relay join requests.

Current Situation

We always send WFCnt of 0 while setting uplink forwarding rules, and do not retrieve the WFCnt periodically. This has the moderate effect of not allowing us to track the relay-end device interactions and also leaves the relay open to potential attacks in some very specific cases.

Why do we need this? Who uses it, and when?

In order to keep the WFCnt tracking on the Network Server side too, for reasons mentioned above.

Proposed Implementation

Similar to how we have a time triggered and frame counter triggered way of sending DevStatusReq, we should have a double trigger for these refreshes.

Contributing

• I can help by doing more research.
• I can help by implementing the feature after the proposal above is approved.
• I can help by testing the feature before it's released.

Code of Conduct

• I agree to follow TTN's Community Code of Conduct.