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From: Richard Sharpe <realrichardsharpe-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
To: Johannes Berg <johannes-cdvu00un1VgdHxzADdlk8Q@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 09:21:17 -0700
Message-ID: <CACyXjPwSZPV+U_=zQpDBpeBnhMntzEFhyJnBOw3-N8qPfyHc1A@mail.gmail.com> (raw)
In-Reply-To: <1440402013.3735.1.camel-cdvu00un1VgdHxzADdlk8Q@public.gmane.org>

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.
  */
 enum ieee80211_radiotap_type {
  IEEE80211_RADIOTAP_TSFT = 0,
@@ -214,6 +219,7 @@
  IEEE80211_RADIOTAP_MCS = 19,
  IEEE80211_RADIOTAP_AMPDU_STATUS = 20,
  IEEE80211_RADIOTAP_VHT = 21,
+ IEEE80211_RADIOTAP_DMG = 22,

  /* valid in every it_present bitmap, even vendor namespaces */
  IEEE80211_RADIOTAP_RADIOTAP_NAMESPACE = 29,

Also, there is the matter of whether or not we need to indicate Static
Tone Pairing and Dynamic Tone Pairing as that is a bit in the PHY
header and is needed to make sense of MCS values 13-17, maybe.

-- 
Regards,
Richard Sharpe
(何以解憂?唯有杜康。--曹操)

  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 [this message]
     [not found]                 ` <CACyXjPwSZPV+U_=zQpDBpeBnhMntzEFhyJnBOw3-N8qPfyHc1A-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-08-24 16:28                   ` Johannes Berg
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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