Re: [PATCH bpf-next] net-bpf: bpf_skb_change_proto() - add support for ipv6 fragments

[Song Liu]

On Tue, Nov 23, 2021 at 3:06 PM Maciej Żenczykowski
<zenczykowski@xxxxxxxxx> wrote:
>
> From: Maciej Żenczykowski <maze@xxxxxxxxxx>
>
> IPv4 fragments (20 byte IPv4 header) need to be translated to/from
> IPv6 fragments (40 byte IPv6 header with additional 8 byte IPv6
> fragmentation header).
>
> This allows this to be done by adding an extra flag BPF_F_IPV6_FRAGMENT
> to bpf_skb_change_proto().
>
> I think this is already technically achievable via the use of
> bpf_skb_adjust_room() which was added in v4.12 commit 2be7e212d541,
> but this is far easier to use and eliminates the need to call two
> helper functions, so it's also faster.
>
> Cc: Lorenzo Colitti <lorenzo@xxxxxxxxxx>
> Signed-off-by: Maciej Żenczykowski <maze@xxxxxxxxxx>

Please add a selftest to exercise the new flag.

Thanks,
Song