Create copy of packate given to BPF

Create copy of packate given to BPF

[Matheus Salgueiro Castanho]

Hi,

I'd like to create a copy of a packet inside a BPF program, alter some
of its headers and redirect it and the original packet to different
interfaces, either on XDP or TC layers.

By taking a look at the helpers list, I have the impression this is
not currently supported, but as things evolve rapidly in the BPF area,
I want to make sure I'm not overlooking anything.

So, is there a way to do this today?

Thanks,
Matheus Castanho

Re: Create copy of packate given to BPF

[Toke Høiland-Jørgensen]

Matheus Salgueiro Castanho <matheus.castanho@dcc.ufmg.br> writes:

> Hi,
>
> I'd like to create a copy of a packet inside a BPF program, alter some
> of its headers and redirect it and the original packet to different
> interfaces, either on XDP or TC layers.
>
> By taking a look at the helpers list, I have the impression this is
> not currently supported, but as things evolve rapidly in the BPF area,
> I want to make sure I'm not overlooking anything.
>
> So, is there a way to do this today?

You're quite right, there isn't. There's work in progress, though, which
will eventually allow this (for XDP):

https://lore.kernel.org/bpf/20200907082724.1721685-1-liuhangbin@gmail.com/

-Toke

Re: Create copy of packate given to BPF

[Matheus Castanho]

On 10/4/20 6:20 PM, Toke Høiland-Jørgensen wrote:
> Matheus Salgueiro Castanho <matheus.castanho@dcc.ufmg.br> writes:
>
>> Hi,
>>
>> I'd like to create a copy of a packet inside a BPF program, alter some
>> of its headers and redirect it and the original packet to different
>> interfaces, either on XDP or TC layers.
>>
>> By taking a look at the helpers list, I have the impression this is
>> not currently supported, but as things evolve rapidly in the BPF area,
>> I want to make sure I'm not overlooking anything.
>>
>> So, is there a way to do this today?
> You're quite right, there isn't. There's work in progress, though, which
> will eventually allow this (for XDP):
>
> https://lore.kernel.org/bpf/20200907082724.1721685-1-liuhangbin@gmail.com/
>
> -Toke
>
Thanks for the confirmation, Toke. I'll keep an eye on that patch then.

Thanks,
Matheus Castanho