Re: [PATCH nft 2/3] meta: add short-hand mnemonic for probalistic matching

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

On Thu, Jul 14, 2016 at 02:08:40PM +0200, Florian Westphal wrote:
> Pablo Neira Ayuso <pablo@netfilter.org> wrote:
> > But if the user introduces a meta random value that can be mapped to
> > probability datatype, we would still hit this asymmetry, right? So the
> > guess game would fail and the user would get confused.
> 
> Yes, but thats not really different from what we do with dependency
> removal, e.g. with 'ip protocol tcp tcp dport 22', the 'ip protocol tcp'
> is still elided from list output since its redundant.

Dependencies are a different thing, they are dealing with redundant
information. This is about what datatype userspace should use to
intepret data.

> > > Nothing, but the meta random might be interesting to e.g. set random
> > > (ct)mark for load balancing purposes.
> > 
> > Could you have a look at the libnftnl userdata tlv infrastructure? We
> > can probably place this information the RULE_USERDATA so we provide an
> > explicit indication to userspace of how to interpret this.  Currently
> > this is only used for rule comments, but we can stash this
> > how-to-interpret-this information there.
> 
> Sure, I will have a look.  It might take a while though.

Thanks.