Re: [PATCH iproute2 -next] tc, bpf: finalize eBPF support for cls and act front-end

[Daniel Borkmann <daniel@iogearbox.net>]

On 04/01/2015 02:36 PM, Jamal Hadi Salim wrote:
> On 03/30/15 18:35, Daniel Borkmann wrote:
>> This work finalizes both eBPF front-ends for the classifier and action
>> part in tc, it allows for custom ELF section selection, a simplified tc
>> command frontend (while keeping compat), reusing of common maps between
>> classifier and actions residing in the same object file, and exporting
>> of all map fds to an eBPF agent for handing off further control in user
>> space.
>>
>> It also adds an extensive example of how eBPF can be used, and a minimal
>> self-contained example agent that dumps map data. The example is well
>> documented and hopefully provides a good starting point into programming
>> cls_bpf and act_bpf.
>
> This is excellent work Daniel.

Thanks, Jamal! ;)

[...]
> I realize you are doing this to illustrate the power of ebpf. And it
> is impressive. Do you see this as a way to replace pieces of the
> kernel stack or to aid and abate what the kernel already does?

I see it as a way to offer a generic, fast and 'safe' option for
classifier and action developers to have a programmable data path
in the traffic control subsystem in the kernel, which I think is
very powerful and important in various use-cases. I regard it as
a similar way and elegant solution as tcpdump or nftables resolve
their problems internally, in other words, to provide a _generic_
solution to address _specific, customized_ issues. Perhaps an anti
feature-bloat, if you will. ;) My viewpoint is that this ties well
together into the kernel landscape, and also makes us improve
various other subsystems that it makes use of, successively.

Thanks,
Daniel