From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andy Gospodarek Subject: Re: [PATCH net-next 3/3] net: Add table id from route lookup to route response Date: Wed, 2 Sep 2015 15:43:27 -0400 Message-ID: <20150902194326.GZ504@gospo.home.greyhouse.net> References: <1441212034-37464-1-git-send-email-dsa@cumulusnetworks.com> <1441212034-37464-3-git-send-email-dsa@cumulusnetworks.com> <20150902184346.GB20527@pox.localdomain> <20150902.114914.1705777375118723461.davem@davemloft.net> <55E74546.4070501@cumulusnetworks.com> <20150902190836.GD20527@pox.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: David Ahern , David Miller , netdev@vger.kernel.org To: Thomas Graf Return-path: Received: from mail-qk0-f176.google.com ([209.85.220.176]:33308 "EHLO mail-qk0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755870AbbIBTnb (ORCPT ); Wed, 2 Sep 2015 15:43:31 -0400 Received: by qkdv1 with SMTP id v1so12104559qkd.0 for ; Wed, 02 Sep 2015 12:43:30 -0700 (PDT) Content-Disposition: inline In-Reply-To: <20150902190836.GD20527@pox.localdomain> Sender: netdev-owner@vger.kernel.org List-ID: On Wed, Sep 02, 2015 at 09:08:36PM +0200, Thomas Graf wrote: > On 09/02/15 at 12:51pm, David Ahern wrote: > > On 9/2/15 12:49 PM, David Miller wrote: > > >From: Thomas Graf > > >Date: Wed, 2 Sep 2015 20:43:46 +0200 > > > > > >>On 09/02/15 at 09:40am, David Ahern wrote: > > >>>rt_fill_info which is called for 'route get' requests hardcodes the > > >>>table id as RT_TABLE_MAIN which is not correct when multiple tables > > >>>are used. Use the newly added table id in the rtable to send back > > >>>the correct table. > > >>> > > >>>Signed-off-by: David Ahern > > >> > > >>What RTM_GETROUTE returns is not the actual route but a description > > >>of the routing decision which is why table id, scope, protocol, and > > >>prefix length are hardcoded. This is indicated by the RTM_F_CLONED > > >>flag. What you propose would break userspace ABI. > > > > > >Agreed, I don't think we can do this. > > > > > > > Doesn't the table used to come up with the decision matter for IPv4? ie., > > hardcoding to MAIN is misleading when there is absolutely no way the > > decision comes from that table. IPv6 already returns the table id. > > > > Or is your response that it breaks ABI and hence not going to fix. > > This behaviour comes back from when we still had the IPv4 routing cache > which was flat. So before the routing cache was removed, was the response always RTA_TABLE_MAIN since there was no way to indicate which table may have route if it came from the cache?