[Cake] Possible conntrack lookup improvements

[Toke Høiland-Jørgensen]

Kevin Darbyshire-Bryant <kevin at darbyshire-bryant.me.uk> writes:

>> On 3 May 2019, at 15:16, Jonathan Morton <chromatix99 at gmail.com> wrote:
>> 
>>> On 3 May, 2019, at 4:55 pm, Kevin Darbyshire-Bryant <kevin at darbyshire-bryant.me.uk> wrote:
>>> 
>>> Two patches attached - one is a simple variable elimination with no functional change.  The second changes/simplifies the conntrack tuple lookup & usage.  I’ve had a play and I don’t think I’ve broken any of the host fairness BUT it could do with some more testing, that’s where you come in… 
>> 
>> Looks like sound logic, as long as it does actually work.  It could be a useful speedup for those small CPE devices which need NAT and host-fairness working.
>
> It’s interesting you bring that up - are we sure that ingress host NAT
> fairness works in the upstream kernel version of CAKE anyway?  I’m
> looking at cake_update_flowkeys(…) and thinking half of it is missing?

No, it's just moved into nf_conntrack_get_tuple_skb(); this was part of
the work we did to ensure sch_cake could load without a dependency on
the conntrack module...

It does carry over the 'nf_ct_tuple(ct, !hash->tuple.dst.dir);' and the
subsequent reversion, though, but I think the logic fits what's in the
out-of-tree version?

-Toke