From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefano Brivio Subject: Re: [PATCH net] ipv6: set all.accept_dad to 0 by default Date: Tue, 14 Nov 2017 03:42:09 +0100 Message-ID: <20171114034209.4fddc3f2@elisabeth> References: <20171113134536.15382-1-nicolas.dichtel@6wind.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: Nicolas Dichtel , David Miller , netdev , Matteo Croce , Maciej =?UTF-8?B?xbtlbmN6eWtvd3NraQ==?= To: Erik Kline Return-path: Received: from mx1.redhat.com ([209.132.183.28]:52962 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750806AbdKNCmS (ORCPT ); Mon, 13 Nov 2017 21:42:18 -0500 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On Mon, 13 Nov 2017 14:21:52 +0000 Erik Kline wrote: > Alternatively, if we really want to make all, default, and ifname > useful perhaps we need to investigate a tristate option (for currently > boolean values, at least). -1 could mean no preference, for example. I think this would make sense in general, but on the other hand it would be quite a big change, and Nicolas' patch has the advantages of being small, keeping the global flag functional, and restoring the previous default behaviour out of the box when 'accept_dad' is disabled by the user for a given interface. Besides, this still wouldn't solve the case where flags are >= 0 and conflicting -- there, it's still debatable whether we want a logical OR or a logical AND. In the end, I would prefer either Nicolas' patch, or to get rid of the global 'accept_dad' flag altogether. Having a flag which does absolutely nothing, which was the case before 35e015e1f577, doesn't sound correct by any means. -- Stefano