Disable frame-counter validation / skipFCntCheck Bug

ChirpStack (v4)
1

Hello, I found a bug when trying to disable frame count validation when creating or updating a device via the API.

I used the routes / chirpstack version
PUT → /api/devices/{device.devEui}
POST → /api/devices
Chirpstack version 4.0.0

I’m setting skipFCntCheck to True, but when creating or updating the device and doing a GET afterwards, it returns False.

Python:

            'device': {
                'applicationId': application_id.replace('-', ''),
                'description': parsed_device_eui.replace('-', ''),
                'devEui': parsed_device_eui,
                'deviceProfileId': device_profile,
                'name': parsed_device_eui,
                'referenceAltitude': 0,
                'skipFCntCheck': True,
            }

The only way I can update is using chirpstack web, manually disabling it. However, I have 1500 devices that need to disable frame count validation and I would like to use the API to create a script for this.

  • Is there any version of chirpstack where this bug has already been fixed?

Thank you.

2

I don’t use this functionality (and recommend against it for security reasons), but I believe I read that devices need to rejoin after enabling it. Have you tried rejoining any of the devices and see if they pick as True?

3

Thanks for the feedback. Yes, the device did the rejoin, but it still didn’t work.

The bug exists when we make the creation/update request via REST API. I was using the python request library, and doing the POST/PUT

But I managed to solve the problem, when I used the chirpstack-api library via grpc it worked, I was able to create and update the device with skipFrameCount=True.

This was the Python code used that solved the problem:

    from chirpstack_api import api
    auth_token = [('authorization', f'Bearer {chirp_stack_api_key}')]
    channel = grpc.insecure_channel(chirp_stack_server)
    client = api.DeviceServiceStub(channel)

      request = api.UpdateDeviceRequest()
      request.device.dev_eui = device_eui
      request.device.name = device_eui
      request.device.description = device_eui
      request.device.application_id = application_id
      request.device.device_profile_id = profile_id
      request.device.skip_fcnt_check = True
      client.Update(request, metadata=auth_token)

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