From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from shards.monkeyblade.net ([184.105.139.130]:56780 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753397AbeB0PrK (ORCPT ); Tue, 27 Feb 2018 10:47:10 -0500 Date: Tue, 27 Feb 2018 10:47:08 -0500 (EST) Message-Id: <20180227.104708.1983037304358643327.davem@davemloft.net> To: sd@queasysnail.net Cc: dsahern@gmail.com, netdev@vger.kernel.org Subject: Re: [PATCH net-next] ipv6: allow userspace to add IFA_F_OPTIMISTIC addresses From: David Miller In-Reply-To: <20180227141328.GA15131@bistromath.localdomain> References: <20180226165619.GA10603@bistromath.localdomain> <20180226.121127.2237252602192340288.davem@davemloft.net> <20180227141328.GA15131@bistromath.localdomain> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org List-ID: From: Sabrina Dubroca Date: Tue, 27 Feb 2018 15:13:28 +0100 > 2018-02-26, 12:11:27 -0500, David Miller wrote: >> From: Sabrina Dubroca >> Date: Mon, 26 Feb 2018 17:56:19 +0100 >> >> That's completely different to this case, which is a bonfide explicit >> allowance for userspace to take over these fundamental protocol tasks >> from the kernel. > > This is not letting userspace take over. On the contrary, it allows > userspace to take advantage of the kernel's DAD, without suffering the > delay. The alternative, without optimistic DAD, would be to completely > disable DAD done by the kernel. > > This follows RFC 4429, which explicitly allows optimistic DAD for > addresses generated by (among other mechanisms) DHCPv6. Fair enough. We can resume this conversation if and when problems pop up in the future :-)