netdev - Re: [RFC PATCH bpf-next] bpf: add bpf_get_skb

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Message-ID: <ca36641c-8360-c2d5-7cde-f4c7d933520a@gmail.com>
Date:   Wed, 12 Aug 2020 15:13:52 -0600
From:   David Ahern <dsahern@...il.com>
To:     "Ramamurthy, Harshitha" <harshitha.ramamurthy@...el.com>,
        "bpf@...r.kernel.org" <bpf@...r.kernel.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "ast@...nel.org" <ast@...nel.org>,
        "daniel@...earbox.net" <daniel@...earbox.net>,
        "davem@...emloft.net" <davem@...emloft.net>,
        "kuba@...nel.org" <kuba@...nel.org>, "kafai@...com" <kafai@...com>,
        "songliubraving@...com" <songliubraving@...com>,
        "yhs@...com" <yhs@...com>, "andriin@...com" <andriin@...com>,
        "john.fastabend@...il.com" <john.fastabend@...il.com>,
        "kpsingh@...omium.org" <kpsingh@...omium.org>,
        "hawk@...nel.org" <hawk@...nel.org>
Cc:     "Herbert, Tom" <tom.herbert@...el.com>,
        "Keller, Jacob E" <jacob.e.keller@...el.com>,
        "Duyck, Alexander H" <alexander.h.duyck@...el.com>,
        "Wyborny, Carolyn" <carolyn.wyborny@...el.com>
Subject: Re: [RFC PATCH bpf-next] bpf: add bpf_get_skb_hash helper function

On 8/11/20 3:55 PM, Ramamurthy, Harshitha wrote:
> is a pre-cursor to potentially calling the in-kernel flow dissector from
> a helper function.
> 

That is going to be a challenge to do in a way that does not impact the
kernel's ability to change as needed, and I suspect it will be much
slower than doing in ebpf. Modular ebpf code that can be adapted to use
cases is going to be more appropriate for XDP for example.