From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <netdev-owner@vger.kernel.org>
Received: from mx3-rdu2.redhat.com ([66.187.233.73]:51538 "EHLO mx1.redhat.com"
        rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP
        id S1751663AbeCCLXB (ORCPT <rfc822;netdev@vger.kernel.org>);
        Sat, 3 Mar 2018 06:23:01 -0500
Date: Sat, 3 Mar 2018 12:22:36 +0100
From: Stefano Brivio <sbrivio@redhat.com>
To: David Ahern <dsahern@gmail.com>
Cc: "David S . Miller" <davem@davemloft.net>,
        Wei Wang <weiwan@google.com>,
        Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
        Maciej =?UTF-8?B?xbtlbmN6?= =?UTF-8?B?eWtvd3NraQ==?=
        <maze@google.com>, netdev@vger.kernel.org
Subject: Re: [PATCH net] ipv6: Reflect MTU changes on PMTU of exceptions for
 MTU-less routes
Message-ID: <20180303122236.6dde3a9b@epycfail>
In-Reply-To: <84593e49-357b-818c-79c5-d265d8c32b03@gmail.com>
References: <81bfe26bed31319d765a4ebfe86705a49c0a39d5.1520003901.git.sbrivio@redhat.com>
        <84593e49-357b-818c-79c5-d265d8c32b03@gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: netdev-owner@vger.kernel.org
List-ID: <netdev.vger.kernel.org>

On Fri, 2 Mar 2018 15:39:03 -0700
David Ahern <dsahern@gmail.com> wrote:

> On 3/2/18 8:36 AM, Stefano Brivio wrote:
> > Currently, administrative MTU changes on a given netdevice are
> > not reflected on route exceptions for MTU-less routes, with a
> > set PMTU value, for that device:
> > 
> >  # ip -6 route get 3000::b
> >  3000::b from :: dev vti_a proto kernel src 3000::a metric 256 pref medium
> >  # ping6 -c 1 -q -s10000 3000::b > /dev/null
> >  # ip netns exec a ip -6 route get 3000::b
> >  3000::b from :: dev vti_a src 3000::a metric 0
> >      cache expires 571sec mtu 4926 pref medium
> >  # ip link set dev vti_a mtu 3000
> >  # ip -6 route get 3000::b
> >  3000::b from :: dev vti_a src 3000::a metric 0
> >      cache expires 571sec mtu 4926 pref medium
> >  # ip link set dev vti_a mtu 9000
> >  # ip -6 route get 3000::b
> >  3000::b from :: dev vti_a src 3000::a metric 0
> >      cache expires 571sec mtu 4926 pref medium  
> 
> Addresses in the 2001:db8: range should be used for commit messages.

Thanks for pointing this out. I never related the "documentation
purposes" from RFC3849 to commit messages so far, but in the end this
is nothing else than documentation. I will post a v2 with updated
commit message.

> And please codify the above expectation as a test under
> tools/testing/selftests/net

And this, along with v2.

-- 
Stefano