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

From: Daniel Borkmann <[email-masked]>
Date: Thu, 02 Apr 2015 02:24:13 +0200

Hi Hannes,

On 04/02/2015 02:13 AM, Hannes Frederic Sowa wrote:
...
> Maybe a small utility programs like:
>
> bpf (--lookup|--update|--delete|--get-next-key) -fd
> filedescriptor-number (type conversion parameters here) key [value]
>
> So it can be easily used by shell scripts.
>
> For that the filedescriptor numbers would need to be exported (already
> opened) into a spawned shell and the numbers could be specified either
> in environment or just by printing text which can be sourced by shells
> (we already talked about the maybe exec 5</proc/pid/fd/1234 idea). Seems
> this can be just build ontop this current patch by extending the
> bpf-agent you already build, no?

I was thinking about that and trying it out, but as far as I can tell,
due to the anon inodes that are currently underlying as the fd provider,
it doesn't work w/o larger kernel changes. So, the file descriptor passing
is currently the only way to transfer control.

Cheers,
Daniel