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Subject: Re: [PATCH 2/2] mac80211: Support LIVE_ADDRESS_CHANGE feature
To:     Johannes Berg <johannes@sipsolutions.net>,
        James Prestwood <prestwoj@gmail.com>,
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From:   Denis Kenzior <denkenz@gmail.com>
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Date:   Tue, 8 Oct 2019 13:50:55 -0500
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Hi Johannes,

>> But they shouldn't change due a mac address change?  I wonder if we can
>> further relax the requirements to allow mac change if
>> NL80211_SCAN_FLAG_RANDOM_ADDR was used?
> 
> No, at least with HW scan that would completely confuse the driver -
> since from the driver's POV we'd remove the interface it's currently
> managing the scan for.

So help me understand this better.  Just by virtue of copying the new 
mac into sdata->vif.addr we'd be confusing the driver such that it can't 
associate the ongoing scan request to the wdev it was started on?  Even 
when it has all this info?  I mean you have a single scan request on a 
phy, how hard can this be? :)

Note that some apps perform poor-man's scan address randomization by 
varying the mac (I assume prior to each nth scan).  So being able to 
change the mac while scanning might be a boon to them.  I personally 
don't think changing mac via rtnl to accomplish this is a great idea, 
but just tossing it out for you.

Regards,
-Denis