Return-path: Received: from nbd.name ([46.4.11.11]:50377 "EHLO nbd.name" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752570AbaFIIAn (ORCPT ); Mon, 9 Jun 2014 04:00:43 -0400 Message-ID: <53956986.8070603@openwrt.org> (sfid-20140609_100046_999688_EFF6E023) Date: Mon, 09 Jun 2014 10:00:06 +0200 From: Felix Fietkau MIME-Version: 1.0 To: Johannes Berg , "Luis R. Rodriguez" CC: "John W. Linville" , Janusz Dziedzic , "wireless-regdb@lists.infradead.org" , linux-wireless Subject: Re: [PATCH] wireless-regdb: add DFS CAC time parameter References: <1399624824-9204-1-git-send-email-janusz.dziedzic@tieto.com> <20140520142453.GB13981@tuxdriver.com> <20140520180832.GD13981@tuxdriver.com> <1400610273.4474.6.camel@jlt4.sipsolutions.net> (sfid-20140520_204832_656990_FF6AC676) <1400688233.4136.8.camel@jlt4.sipsolutions.net> In-Reply-To: <1400688233.4136.8.camel@jlt4.sipsolutions.net> Content-Type: text/plain; charset=UTF-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: On 2014-05-21 18:03, Johannes Berg wrote: > On Tue, 2014-05-20 at 11:48 -0700, Luis R. Rodriguez wrote: > >> > I think we should, but if we can't then at least can we cut to an >> > extensible format? > > I don't see any way to extend the format right now. > > There's a wrinkle with making it more extensible too though - if we do > that then we must be extremely careful that future older crda versions > (i.e. the next version that we're about to write) will not parse a newer > extended file more permissively, so our extensions are limited anyway. > > Looks like the format update really is needed, which probably means we > should change the scripts to generate two databases and change the > filename, or so? How about making the format properly extensible by reusing what we're already doing to keep the kernel ABI stable? For example, we could store the database in a netlink-like attribute format, with some changes to make it fixed endian. I'm already doing just that for a few things in OpenWrt, so I have working C code for writing and parsing such a format. Another nice feature would be to indicate in the attributes if crda is required to understand them, or if it can just continue with a warning. If done right, I think we can probably make this the last time we change the format version. - Felix