Re: [PATCH] net-sysfs: Add entry for nl80211 interface type

2013-04-18 Thread Paul Stewart
The original reason to request this change was simple: to figure out
what type of interface we are looking at, since now some wireless
drivers can simultaneously create managed, p2p and ap interfaces.
Knowing that, from a simple front-end (let's even say a shell script)
we can decide what arguments to use with wpa_supplicant (or indeed if
we want to start it on this interface).  wpa_supplicant, of course,
knows how to manipulate the device further using nl80211.  I thought
it was a bit onerous to force userspace all the way through nl80211
just to get this trivial piece of information, but apparently this
doesn't seem to be the common point of view.

--
Paul

On Wed, Apr 17, 2013 at 11:43 PM, Marcel Holtmann  wrote:
> Hi Nicolas,
>
 Add a "wireless/nl80211_iftype" entry in the net device sysfs
 file structure to indicate the mode of the wireless device so
 it can be discovered easily from userspace.
>>>
>>> What's wrong with "iw dev", i.e. netlink/nl80211?
>>
>> "Do NOT screenscrape this tool, we don't consider its output stable."
>>
>> So if you are in a shell script, you're basically screwed.
>
> if you are in a shell script, you are screwed no matter what. So what is your 
> point?
>
> Regards
>
> Marcel
>
>
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Re: [PATCH] net-sysfs: Add entry for nl80211 interface type

2013-04-22 Thread Paul Stewart
On Mon, Apr 22, 2013 at 6:29 AM, Johannes Berg
 wrote:
>
> On Wed, 2013-04-17 at 15:14 -0700, Paul Stewart wrote:
> > I believe the documents for "iw" state explicitly that we shouldn't
> > screen-scrape it?
>
> Well, you specifically control your system. I'd also be happy to add
> some (maybe a bit hidden) commands to print out _just_ the (numeric)
> type, to aid scripting?


No need.  I already made the necessary changes in userspace to switch
to nl80211 to retrieve the iftype.  Both Bing and I are done
proselytizing at this point. :-)

>
> All I'm trying to say with that though is that
> you shouldn't rely on specific output formatting, particularly not with
> scan results and "iw list" etc.
>
> johannes
>
>
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