netdev - Re: [RFC PATCH bpf-next 0/3] Add a new bpf helper for FDB lookup

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Date:   Fri, 7 Aug 2020 17:30:16 +0900
From:   Yoshiki Komachi <komachi.yoshiki@...il.com>
To:     David Ahern <dsahern@...il.com>,
        John Fastabend <john.fastabend@...il.com>
Cc:     "David S. Miller" <davem@...emloft.net>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Jesper Dangaard Brouer <hawk@...nel.org>,
        Jakub Kicinski <kuba@...nel.org>,
        Martin KaFai Lau <kafai@...com>,
        Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>,
        Andrii Nakryiko <andriin@...com>,
        KP Singh <kpsingh@...omium.org>,
        Roopa Prabhu <roopa@...ulusnetworks.com>,
        Nikolay Aleksandrov <nikolay@...ulusnetworks.com>,
        David Ahern <dsahern@...nel.org>,
        Networking <netdev@...r.kernel.org>,
        bridge@...ts.linux-foundation.org, bpf <bpf@...r.kernel.org>
Subject: Re: [RFC PATCH bpf-next 0/3] Add a new bpf helper for FDB lookup


> 2020/08/06 1:36、David Ahern <dsahern@...il.com>のメール:
> 
> On 8/5/20 4:26 AM, Yoshiki Komachi wrote:
>>> 
>>> Just to clarify for myself. I expect that with just the helpers here
>>> we should only expect static configurations to work, e.g. any learning
>>> and/or aging is not likely to work if we do redirects in the XDP path.
>> 
>> As you described above, learning and aging don’t work at this point. 
>> 
>> IMO, another helper for learning will be required to fill the requirements.
>> I guess that the helper will enable us to use the aging feature as well
>> because the aging is the functionality of bridge fdb.
> 
> One option is to have a flag that bumps the ageing on successful lookup
> and do that in 1 call. You will already have access to the fdb entry.

It seems like a good idea to me! I guess that the flags in my suggested bpf
helper for the FDB lookup will be useful for such a case.

Thanks & Best regards,

—
Yoshiki Komachi
komachi.yoshiki@...il.com