From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1751977AbeCOQgT (ORCPT <rfc822;w@1wt.eu>);
        Thu, 15 Mar 2018 12:36:19 -0400
Received: from userp2130.oracle.com ([156.151.31.86]:44016 "EHLO
        userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1751458AbeCOQgS (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Thu, 15 Mar 2018 12:36:18 -0400
MIME-Version: 1.0
Message-ID: <e653a52e-6a7d-49c9-aec6-6bc6437819c6@default>
Date: Thu, 15 Mar 2018 09:35:51 -0700 (PDT)
From: Liran Alon <liran.alon@oracle.com>
To: <shmulik.ladkani@gmail.com>
Cc: <netdev@vger.kernel.org>, <daniel@iogearbox.net>, <mrv@mojatatu.com>,
        <davem@davemloft.net>, <linux-kernel@vger.kernel.org>,
        <yuval.shaia@oracle.com>, <idan.brown@oracle.com>
Subject: Re: [PATCH] net: dev_forward_skb(): Scrub packet's per-netns info
 only when crossing netns
X-Mailer: Zimbra on Oracle Beehive
Content-Type: text/plain; charset=UTF-8
Content-Disposition: inline
X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=8832 signatures=668690
X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=1 malwarescore=0
 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=605
 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1
 engine=8.0.1-1711220000 definitions=main-1803150169
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org
Content-Transfer-Encoding: 8bit
X-MIME-Autoconverted: from quoted-printable to 8bit by mail.home.local id w2FGaPub021222


----- shmulik.ladkani@gmail.com wrote:

> On Thu, 15 Mar 2018 08:01:03 -0700 (PDT) Liran Alon
> <liran.alon@oracle.com> wrote:
> > 
> > I still think that default behavior should be to zero skb->mark only
> when skb
> > cross netdevs in different netns.
> 
> But the previous default was scrub the mark in *both* xnet and
> non-xnet
> situations.
> 
> Therefore, there might be users which RELY on this (strange) default
> behavior in their same-netns-veth-pair setups.
> Meaning, changing the default behavior might break their apps relying
> on
> the former default behavior.
> 
> This is why the "disable mark scrubbing in non-xnet case" should be
> opt-in.

We think the same.
The only difference is that I think this for now should be controllable
by a global /proc/sys/net/core file instead of giving a flexible per-netdev control.
Because that is a larger change that could be done later.

> 
> Regards,
> Shmulik