From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: [PATCH RFC v2 net-next 00/25] rtnetlink: Add support for rigid checking of data in dump request Date: Wed, 3 Oct 2018 07:59:09 -0700 Message-ID: <20181003075909.4d977567@xeon-e3> References: <20181002002851.5002-1-dsahern@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, davem@davemloft.net, christian@brauner.io, jbenc@redhat.com, David Ahern To: David Ahern Return-path: Received: from mail-pf1-f195.google.com ([209.85.210.195]:46305 "EHLO mail-pf1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726748AbeJCVr7 (ORCPT ); Wed, 3 Oct 2018 17:47:59 -0400 Received: by mail-pf1-f195.google.com with SMTP id r64-v6so1799279pfb.13 for ; Wed, 03 Oct 2018 07:59:14 -0700 (PDT) In-Reply-To: <20181002002851.5002-1-dsahern@kernel.org> Sender: netdev-owner@vger.kernel.org List-ID: On Mon, 1 Oct 2018 17:28:26 -0700 David Ahern wrote: > How to resolve the problem of not breaking old userspace yet be able to > move forward with new features such as kernel side filtering which are > crucial for efficient operation at high scale? What about forward compatibility? How would this work when running new iproute2 command on older kernels? I expect the new command would set the "I am smart flag" and the older kernel would ignore it. The if the header for the message type had changed, the dump would be broken.