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From: Johannes Berg <johannes-cdvu00un1VgdHxzADdlk8Q@public.gmane.org>
To: Richard Sharpe
	<realrichardsharpe-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: Guy Harris <guy-FrUbXkNCsVf2fBVCVOL8/A@public.gmane.org>,
	radiotap-S783fYmB3Ccdnm+yROfE0A@public.gmane.org
Subject: Re: Correct radiotap header for 802.11ad
Date: Mon, 24 Aug 2015 18:28:35 +0200
Message-ID: <1440433715.3735.23.camel@sipsolutions.net> (raw)
In-Reply-To: <CACyXjPwSZPV+U_=zQpDBpeBnhMntzEFhyJnBOw3-N8qPfyHc1A-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> (sfid-20150824_182119_074806_8384E579)

On Mon, 2015-08-24 at 09:21 -0700, Richard Sharpe wrote:
> On Mon, Aug 24, 2015 at 12:40 AM, Johannes Berg
> <johannes-cdvu00un1VgdHxzADdlk8Q@public.gmane.org> wrote:
> > On Sat, 2015-08-22 at 16:34 -0700, Guy Harris wrote:
> > > 
> > > For what it's worth, it appears that the wil6210 driver:
> > > 
> > >       https://wireless.wiki.kernel.org/en/users/drivers/wil6210
> > > 
> > > uses the MCS field and its mcs value for 11ad.  It can also be
> > > configured to supply raw "PHY data" with a vendor-namespace field.
> > > 
> > > So code that processes radiotap headers, such as Wireshark's radiotap
> > > -header dissector, will have to interpret packets with an MCS field
> > > and a channel frequence in the 11ad range as being 11ad packets, and
> > > treat the mcs value in the MCS field as an 11ad MCS, not an 11n MCS.
> > 
> > That just seems really lazy though - I think we should rather fix that
> > driver and define a proper 60G radiotap field.
> 
> Can I suggest something like the following, although we have defined
> the presence flags as a UINT32 for the moment in Wireshark:
> 
> --- ../linux-3.11-rc6/include/net/ieee80211_radiotap.h 2013-10-20
> 13:34:23.633866699 -0700
> +++ ./include/net/ieee80211_radiotap.h 2015-08-24 09:12:12.416137951 -0700
> @@ -190,6 +190,11 @@
>   * IEEE80211_RADIOTAP_VHT u16, u8, u8, u8[4], u8, u8, u16
>   *
>   * Contains VHT information about this frame.
> + *
> + * IEEE80211_RADIOTAP_DMG       u8, u8
> + *
> + *      Contains DMG information about the frame. Currently presence flags
> + *      and the MCS index, if present.
> 

I'm not sure that'll work - the format can't really be variable, so
having presence flags and just the MCS isn't useful (since if you don't
know the MCS, then you might as well not include the DMG field at all)

We need to define the full set of information we might want, but I'm
not nearly familiar enough with DMG to suggest what might be needed.

johannes

  parent reply index

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-08-22 19:41 Richard Sharpe
     [not found] ` <CACyXjPzq-ePB1ux6wi_Rv3onPKXomcJcm15XJwA51u0E4W2txw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-08-22 20:59   ` Guy Harris
     [not found]     ` <38F46E1D-1C4A-48DC-A906-9522006E8474-FrUbXkNCsVf2fBVCVOL8/A@public.gmane.org>
2015-08-22 22:06       ` Richard Sharpe
     [not found]         ` <CACyXjPx81fh_jeQSUjE-_w8NQ_Jr-ajmnVWSopfzcLPOWoGmGg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-08-22 22:24           ` Guy Harris
2015-08-22 23:34       ` Guy Harris
     [not found]         ` <1606812C-649C-4C06-ABE0-AE2F4474BCD0-FrUbXkNCsVf2fBVCVOL8/A@public.gmane.org>
2015-08-24  7:40           ` Johannes Berg
     [not found]             ` <1440402013.3735.1.camel-cdvu00un1VgdHxzADdlk8Q@public.gmane.org>
2015-08-24 16:21               ` Richard Sharpe
     [not found]                 ` <CACyXjPwSZPV+U_=zQpDBpeBnhMntzEFhyJnBOw3-N8qPfyHc1A-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-08-24 16:28                   ` Johannes Berg [this message]
2015-08-26 22:59                   ` Simon Barber
     [not found]                     ` <55DE44EB.6080603-vp0mx6+5gkqFX2APIN6yfw@public.gmane.org>
2015-08-27  1:17                       ` Guy Harris
     [not found]                         ` <126B842D-05EA-4510-BC9B-DB1A4AABEC12-FrUbXkNCsVf2fBVCVOL8/A@public.gmane.org>
2015-09-10 18:25                           ` Guy Harris
     [not found]                             ` <1135A126-6A5A-4C84-A52D-13C0387609CC-FrUbXkNCsVf2fBVCVOL8/A@public.gmane.org>
2015-09-17 16:37                               ` Johannes Berg
2019-12-10 23:51                                 ` Guy Harris
2019-12-11  8:32                                   ` Johannes Berg
2019-12-11  9:39                                     ` Krishna Chaitanya
2019-12-11 12:57                                       ` Johannes Berg
2019-12-11 13:20                                         ` Krishna Chaitanya
2019-12-20 21:56                                     ` Guy Harris
2015-09-17 16:32                       ` Johannes Berg
2015-08-26 22:56       ` Simon Barber

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