enhancing nfnetlink stats [was Re: [PATCH net-next] change nfqueue failopen to apply also to receive message buffer in addition to queue size]

[Pablo Neira Ayuso <pablo@netfilter.org>]

On Wed, Mar 23, 2016 at 12:04:28PM +0000, Yigal Reiss (yreiss) wrote:
> >>  -	seq_printf(s, "%5u %6u %5u %1u %5u %5u %5u %8u %2d\n", +
> >>  seq_printf(s, "%5u %6u %5u %1u %5u %5u %5u %8u %5u %5u %2d\n",
> > Problematic since it changes layout of a file we unfortunately
> > have to view as uapi.  I would prefer if we could leave the proc
> > file alone and not add any new stats counters for this, unless
> > there is a good argument for doing so.
>
> So my arguments are that there in order to fine tune a system it is
> required to know about the existence and number of packets that went
> under the radar. As I wrote ENOBUF does not answer all these needs.
> I understand it is problematic to change uapi. Tried to minimize
> incompatibility by keeping the order of arguments. I'll probably use
> a patch to proc any way. Please let me know if you think there is a
> point in proposing this patch or is it a "no-no" from kernel's
> perspective.

I'd suggest you extend the existing nfnetlink_queue infrastructure so
we retrieve these statistics through netlink, ie. add the
NFQNL_MSG_STATS message. Then, extend nft so we can list them via:

# nft list queues
... [ stats here ] ...