Date: Sun, 25 Mar 2007 22:38:39 -0500 From: David Young To: Pavel Roskin Cc: linux-wireless-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Scott Raynel , radiotap-eZodSLrBbDpBDgjK7y7TUQ@public.gmane.org Subject: Re: RFC: radiotap discrepancy in Linux vs OpenBSD Message-ID: <20070326033839.GA24097-eZ+MEZF6i8Dc+919tysfdA@public.gmane.org> References: <20070325232416.64xwkc0kw04oosg0-2RFepEojUI3Rd1RZctBqVdHuzzzSOjJt@public.gmane.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070325232416.64xwkc0kw04oosg0-2RFepEojUI3Rd1RZctBqVdHuzzzSOjJt@public.gmane.org> User-Agent: Mutt/1.4.1i On Sun, Mar 25, 2007 at 11:24:16PM -0400, Pavel Roskin wrote: > Hello! (Oops, this time cc'd radiotap.) The place to discuss this is the mailing list radiotap-eZodSLrBbDpBDgjK7y7TUQ@public.gmane.org, which I have cc'd. Subscribe at . Please feel free to circulate the URL. > I have noticed two different incompatible changes to enum > ieee80211_radiotap_type in ieee80211_radiotap.h. > > One is found in the current wireless-2.6.git: > > IEEE80211_RADIOTAP_RX_FLAGS = 14, > IEEE80211_RADIOTAP_TX_FLAGS = 15, > IEEE80211_RADIOTAP_RTS_RETRIES = 16, > IEEE80211_RADIOTAP_DATA_RETRIES = 17, These fields are slated to become part of the standard, I just haven't got around to updating the manual page, yet. I have time to do that tonight. > It was added together with Marvell Libertas USB driver. > Another set of the flags can be found in CVS OpenBSD: > > IEEE80211_RADIOTAP_FCS = 14, > IEEE80211_RADIOTAP_HWQUEUE = 15, > IEEE80211_RADIOTAP_RSSI = 16, These fields are not part of the standard, and they will not become part of the standard with these numbers. This is the first time I have ever heard of HWQUEUE and RSSI, actually. What are they for? > I think Marvell developers could act gracefully and push the flags it introduces > to higher numbers. Doing something like that on the OpenBSD side would be > harder. I would also like to see joining Rx and Tx flags into one 32-bit > value. > But we need some coordination when new fields are added to the protocol. Right. People must coordinate on the radiotap list. > Uncalibrated RSSI may also be a candidate for > the driver-specific data if OpenBSD can be persuaded to abandon its present > number. OpenBSD will need to abandon its present numbers in order to stay compatible with tcpdump and wireshark. > It's important that presence of driver specific fields doesn't break parsing of > the standard fields, even if new fields are made standard. I think driver > specific flags don't belong to the it_present bitmap, but should go to the > beginning of the driver specific area. You are right that the driver-specific fields cannot go in the bitmap. Dave -- David Young OJC Technologies dyoung-eZodSLrBbDpBDgjK7y7TUQ@public.gmane.org Urbana, IL * (217) 278-3933