From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Frederic Sowa Subject: Re: [RFC PATCH] net: ipv6: Make address flushing on ifdown optional Date: Mon, 19 Jan 2015 20:11:52 +0100 Message-ID: <1421694712.13047.5.camel@redhat.com> References: <1421263039-96198-1-git-send-email-dsahern@gmail.com> <1421679769.32277.15.camel@redhat.com> <00c901d03402$b5cb6890$216239b0$@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: "'David Ahern'" , netdev@vger.kernel.org To: Harout Hedeshian Return-path: Received: from mx1.redhat.com ([209.132.183.28]:47724 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751423AbbASTMD (ORCPT ); Mon, 19 Jan 2015 14:12:03 -0500 In-Reply-To: <00c901d03402$b5cb6890$216239b0$@codeaurora.org> Sender: netdev-owner@vger.kernel.org List-ID: On Mo, 2015-01-19 at 09:12 -0700, Harout Hedeshian wrote: > > I would still prefer that we flush automatically generated addresses and only > > keep the static and permanent ones. > > > > What do you think? > > > > Bye, > > Hannes > > If I may offer an opinion, I do feel that there are use cases where flushing the auto-generated addresses in ifdown would not be desirable. > > We have one such use case where information regarding the state of the network beyond the interface is managed through sideband signaling. We know that the auto-generated address would still be valid on ifup because the router information is unchanged. In this case, ifup/down is solely being used as a way for user space to enable/disable all traffic on a particular netdevice for temporary periods. > > That said, I'm not sure how useful this would be for the average user; I see no harm if it is configurable and the default behavior is unchanged. Do you think it makes sense to combine the logic with the accept_ra sysctl? accept_ra && !flush_addr_on_down -> flush addresses generated by accept_ra logic !accept_ra && !flush_addr_on_down -> don't flush any addresses I am not sure about that, feels complicated. Would that suite your usecase? Bye, Hannes