Re: make XDP program aware of multi buffer
Henning Fehrmann <[email protected]> Wed, 30 Nov 2022 09:54:35 +0100
| Newsgroups | org.kernel.vger.xdp-newbies |
|---|---|
| Message-ID | <[email protected]> |
> You just replace:
>
> SEC("xdp")
>
> with
>
> SEC("xdp.frags")
>
> in your source file and, assuming your libbpf version is up-to-date,
> that should be it as far as the kernel is concerned.
Nice. It loads now. I appreciate the work done for multi buffer packets.
>
> However, you obviously also need to make sure there are no semantic
> issues in your program before doing this. I.e., data_end is no longer
> the end of your packet, so if you are using data_end-data to calculate
> the packet len, that will no longer be accurate. If you need to access
> data beyond the first frag you'll need to use the
> xdp_{load,store}_bytes() helpers.
I guess, this is not the case or does bpf_redirect needs it if I have
multi frame packets?
I realized that redirection actually doesn't happen if the packets
exceed the page size.
Thank you,
Henning