netdev - Re: New xdpsock sample

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Message-ID: <CAJ8uoz1uZoNYYJd3hXy3pXC2HTG3XWXSVDTO_0BBkMBotxi11Q@mail.gmail.com>
Date:   Tue, 26 Mar 2019 17:24:16 +0100
From:   Magnus Karlsson <magnus.karlsson@...il.com>
To:     Jonathan Lemon <bsd@...com>
Cc:     Maxim Mikityanskiy <maximmi@...lanox.com>,
        Magnus Karlsson <magnus.karlsson@...el.com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        Björn Töpel <bjorn.topel@...el.com>,
        Daniel Borkmann <daniel@...earbox.net>,
        Eran Ben Elisha <eranbe@...lanox.com>,
        Tariq Toukan <tariqt@...lanox.com>,
        Saeed Mahameed <saeedm@...lanox.com>
Subject: Re: New xdpsock sample

On Tue, Mar 26, 2019 at 5:13 PM Jonathan Lemon <bsd@...com> wrote:
>
> The rationale (IIRC) was that it would be easier for new users to
> get started using AF_XDP by providing everything that was needed
> by default.
>
> Passing in XSK_LIBBPF_FLAGS__INHIBIT_PROG to the library will
> bypass loading the sample program, so a user application may still
> use the library with their own bpf program.
>
> I'll admit that the change likely makes it harder to simply modify
> the sample program for other uses, but that's not really the point
> of the samples.
> --
> Jonathan
>
> On 26 Mar 2019, at 8:46, Maxim Mikityanskiy wrote:
>
> > Hi Magnus and all,
> >
> > https://patchwork.ozlabs.org/cover/1045921/
> >
> > This series removes xdpsock_kern.c and replaces it by the bytecode
> > hardcoded in libbpf. I am wondering whether there is some real issue
> > with having the XDP program in a separate C file, just like before,
> > because this change made it far less convenient to modify the XDP
> > program. Could you give any comments?
> >
> > Thanks,
> > Max

How about we reintroduce a sample C XDP program once we have a reason
to use one in the xdpsock program, i.e. for something not covered by
libbpf? I do not have such a use case at the moment, but do you Max?
If so, as you say, it would be good to have an example on how to
accomplish this using the XSK_LIBBPF_FLAGS__INHIBIT_PROG that Jonathan
mentioned.

/Magnus