Re: [PATCH] RFC: Universal scan proposal

[Johannes Berg <johannes@sipsolutions.net>]

> If we go with approach to use parameters and let FW or MAC80211
> layer to decide what type of scan to do, 

At that point though, is it even meaningful to ask "what type of scan
is this"? Or put another way - what does "scan type" even mean?

> then in general the only
> difference between different types of scan is what to do with result:
> - Normal scan: ssid list, channel list, dwell params, etc...
> - Sched scan: ssid list, channel list, interval
> - BSSID scan: bssid list, channel list, interval
> Action: Report when suitable results are found (in case of Normal
> scan it will be at the end of scan)
> 
> - Roaming / Autojoin: ssid list, channel list, interval
> Action: Connect when suitable results are found
> 
> - History scan: bssid list, channel list, interval
> Action: Report when buffer is full / almost full

Exactly. But the type of action is something set by the entity that
triggered the scan, right? normal and roam would be equivalent anyway,
no? wpa_supplicant would make a decision to connect - after the results
are coming in.

Oh, then again, maybe you're thinking of full-MAC devices - does a
roam/autojoin scan really already *imply* a new connection? And if so,
do we have to do it that way, or can we remove that type of action and
make a connection decision in higher layers, so it's really the same as
"report when suitable results are found"?

> So we can literally distinguish scan types by final action.

Actually I think I'm just misinterpreting your wording - you mean that
we can use the different final actions for the different scan types,
not that we should actually say - in driver/firmware/... - "this is a
history scan because the action is to report buffer full", right?

> And for History scan we need new get_scan_results() command.
> 
> Does it sound reasonable?

I think it does.

There's a bit more complication wrt. the level of detail in results
though - sometimes the result may include all IEs (normal/sched scan),
sometimes it may not ("history scan") - are we sure we really only need
one new get_scan_results()?

johannes