Re: [PATCH bpf-next v5 3/3] devmap: Allow map lookups from eBPF

[Jonathan Lemon]

On 22 Jun 2019, at 19:17, Toke Høiland-Jørgensen wrote:

> From: Toke Høiland-Jørgensen <t...@redhat.com>
>
> We don't currently allow lookups into a devmap from eBPF, because the map
> lookup returns a pointer directly to the dev->ifindex, which shouldn't be
> modifiable from eBPF.
>
> However, being able to do lookups in devmaps is useful to know (e.g.)
> whether forwarding to a specific interface is enabled. Currently, programs
> work around this by keeping a shadow map of another type which indicates
> whether a map index is valid.
>
> Since we now have a flag to make maps read-only from the eBPF side, we can
> simply lift the lookup restriction if we make sure this flag is always set.
>
> Signed-off-by: Toke Høiland-Jørgensen <t...@redhat.com>
Acked-by: Jonathan Lemon <jonathan.le...@gmail.com>