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Date:   Fri, 13 Nov 2020 11:40:36 -0800
From:   Jakub Kicinski <kuba@kernel.org>
To:     David Ahern <dsahern@gmail.com>
Cc:     Stefano Salsano <stefano.salsano@uniroma2.it>,
        Andrea Mayer <andrea.mayer@uniroma2.it>,
        "David S. Miller" <davem@davemloft.net>,
        David Ahern <dsahern@kernel.org>,
        Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
        Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
        Shuah Khan <shuah@kernel.org>,
        Shrijeet Mukherjee <shrijeet@gmail.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@chromium.org>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
        Paolo Lungaroni <paolo.lungaroni@cnit.it>,
        Ahmed Abdelsalam <ahabdels.dev@gmail.com>
Subject: Re: [net-next,v2,4/5] seg6: add support for the SRv6 End.DT4
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On Fri, 13 Nov 2020 10:04:44 -0700 David Ahern wrote:
> On 11/13/20 10:02 AM, Stefano Salsano wrote:
> > Il 2020-11-13 17:55, Jakub Kicinski ha scritto:  
> >> On Thu, 12 Nov 2020 18:49:17 -0700 David Ahern wrote:  
> >>> On 11/12/20 6:28 PM, Andrea Mayer wrote:  
> >>>> The implementation of SRv6 End.DT4 differs from the the
> >>>> implementation of SRv6
> >>>> End.DT6 due to the different *route input* lookup functions. For
> >>>> IPv6 is it
> >>>> possible to force the routing lookup specifying a routing table
> >>>> through the
> >>>> ip6_pol_route() function (as it is done in the
> >>>> seg6_lookup_any_nexthop()).  
> >>>
> >>> It is unfortunate that the IPv6 variant got in without the VRF piece.  
> >>
> >> Should we make it a requirement for this series to also extend the v6
> >> version to support the preferred VRF-based operation? Given VRF is
> >> better and we require v4 features to be implemented for v6?  
> > 
> > I think it is better to separate the two aspects... adding a missing
> > feature in IPv4 datapath should not depend on improving the quality of
> > the implementation of the IPv6 datapath :-)
> > 
> > I think that Andrea is willing to work on improving the IPv6
> > implementation, but this should be considered after this patchset...
>
> agreed. The v6 variant has existed for a while. The v4 version is
> independent.

Okay, I'm not sure what's the right call so I asked DaveM.

TBH I wasn't expecting this reaction, we're talking about a 200 LoC
patch which would probably be 90% reused for v6...