Accepted GATT status for write authorization reply?

[abkirchhoff]

I'm sending a write authorization reply using sd_ble_gatts_rw_authorize_reply() in response to a standard Write Request with one byte of data. When I set the gatt_status to BLE_GATT_STATUS_ATTERR_REQUEST_NOT_SUPPORTED, the reply() function returns NRF_ERROR_INVALID_PARAM. However, if I set the gatt_status to BLE_GATT_STATUS_ATTERR_WRITE_NOT_PERMITTED, the reply() function returns NRF_SUCCESS. The other parameters in the authorization reply are the same in both cases.

Is there a reason why BLE_GATT_STATUS_ATTERR_REQUEST_NOT_SUPPORTED cannot be used?

More importantly, What are the valid GATT status codes than can be used for a write authorization reply? What are the valid GATT status codes for a read authorization reply?

I'm using S132 v2.0.1 and SDK 11.0.0 on the nRF52.

Thanks, Austin

[abkirchhoff]

I'm using "request not supported" as a response when the server is in a "bad" state and does not allow the characteristic to change. But that is a good point, "request not supported" is probably more narrowly defined like you described. I should probably use an application-specific error code for this particular case.

Still, if the SoftDevice is going to return an error, it would be nice for the documentation to list which status codes will cause an error.

[abkirchhoff]

Also, I would like to send "request not supported" as a response to a Queued Write, as my server does not support them.

[Petter Myhre]

In Vol. 3, Part F, Section 3.4.5.1 in the Bluetooth Core specification v4.2 it is stated:

If the client has insufficient authorization to write the requested attribute then an Error Response shall be sent with the error code «Insufficient Authorization».

This is the error code you shall use. I'm not sure why the SoftDevice allows you to use write not permitted. I'll have to check that with the developers, and update.