If a netdev iftype is changed, all frame registrations are removed.
Make sure to re-register for the appropriate frame notifications in case
our iftype is switched back to 'station'. In any other iftype, no frame
watches are registered and rrm_state object is effectively dormant.
Right now, RRM is created when a new netdev is detected and its iftype
is of type station. That means that any devices that start their life
as any other iftype cannot be changed to a station and have RRM function
properly. Fix that by always creating the RRM state regardless of the
initial iftype.
In the case that a netdev is powered down, or an interface type change
occurs, the station object will be removed and any watches will be
freed.
Since rrm is created when the netdev is created and persists across
iftype and power up/down changes, it should provide a destroy callback
to station_add_state_watch so that it can be notified when the watch is
removed.
The first if case should be -10950, not 10950. Without the negative
this first case would get hit every time since signal strength values
are always negative.
The RCPI value was using floating point values as per the spec. But instead
we can just use the signal strength coming from the kernel in mili mdm and
scale the hard coded values by a factor of 100.
Beacon requests can specify a scan duration, and set a flag which makes
this duration mandatory. The kernel supports both these values for scan
requests so we no longer need to reject requests which contain these.
Drivers which do not support EXT_FEATURE_SET_SCAN_DWELL will ignore the
duration value, but if duration mandatory is set we must reject the
request.
This module takes care of radio measurements which an AP can request.
There are many types of requests, and for now only beacon requests
are supported.
IWD will filter certain types of beacon requests that are NOT
supported:
- AP channel reports. Only single channel requests will be supported
- Autonomous measurements. Only direct requests will be supported.
IWD will not accept requets to trigger reports under certain
conditions (SNR/RSSI thresholds, etc.)
- Timed measurements. Only immediate measurements will be performed.
The accuracy for timed measurements cannot be reliably guaranteed
due to kernel scheduling/queues.
- Full reporting detail. The AP can request the STA return the full
set of IEs in a beacon. IWD does not currently save all IEs, plus
there is quite a bit of complexity involved as certain IEs get
truncated, and there are other length limitations.
There are other limitations not specific to beacon requests:
- IWD will support single measurement requests per report. Multiple
measurement request IEs can be included, but the reports will be
sent out separately.
- IWD will limit the number of requests it responds to in a given
amount of time. As it stands now this is hard coded to 2 requests
per second maximum. This will prevent DoS attacks.
- IWD will not accept any measurement requests from APs it is not
connected to, and will not accept any requests until connected.
