Re: [PATCH nf-next,RFC 1/3] netfilter: nf_conntrack: add 64-bit conntrack ID extension

[Florian Westphal <fw@strlen.de>]

Pablo Neira Ayuso <pablo@netfilter.org> wrote:
> > > index 21f887c5058c..274f9370c56a 100644
> > > --- a/include/net/netfilter/nf_conntrack_extend.h
> > > +++ b/include/net/netfilter/nf_conntrack_extend.h
> > > @@ -28,6 +28,7 @@ enum nf_ct_ext_id {
> > >  #if IS_ENABLED(CONFIG_NETFILTER_SYNPROXY)
> > >  	NF_CT_EXT_SYNPROXY,
> > >  #endif
> > > +	NF_CT_EXT_ID,
> > 
> > I think, if we decide that this new id is needed,
> > we might as well place this directly in the extension
> > struct itself rather than an id.
> > 
> > AFAIU this id is always active/set so we never have a
> > conntrack without this.
> 
> I understand your goal would be to make this run faster for the first
> packet that is part of the connection. This would fit into the 128 bytes
> that we preallocate, so you're just trying to remove one level of
> indirection, right?

Yes, and save the space in the len/data array for the new extension id.

There is nothing else to it.
We currently do not have an "always on" extension, this would be the
first.