Re: [PATCH net-next v3 0/7] Allow offloading of UDP NEW connections via act_ct

On Fri, Jan 20, 2023 at 08:57:16AM +0200, Vlad Buslov wrote:

On Fri 20 Jan 2023 at 08:38, Vlad Buslov [off-list ref] wrote:

quoted

On Thu 19 Jan 2023 at 18:37, Marcelo Ricardo Leitner [off-list ref] wrote:

quoted

On Thu, Jan 19, 2023 at 08:50:57PM +0100, Vlad Buslov wrote:

quoted

Currently only bidirectional established connections can be offloaded
via act_ct. Such approach allows to hardcode a lot of assumptions into
act_ct, flow_table and flow_offload intermediate layer codes. In order
to enabled offloading of unidirectional UDP NEW connections start with
incrementally changing the following assumptions:

- Drivers assume that only established connections are offloaded and
  don't support updating existing connections. Extract ctinfo from meta
  action cookie and refuse offloading of new connections in the drivers.

Hi Vlad,

Regarding ct_seq_show(). When dumping the CT entries today, it will do
things like:

        if (!test_bit(IPS_OFFLOAD_BIT, &ct->status))
                seq_printf(s, "%ld ", nf_ct_expires(ct)  / HZ);

omit the timeout, which is okay with this new patchset, but then:

        if (test_bit(IPS_HW_OFFLOAD_BIT, &ct->status))
                seq_puts(s, "[HW_OFFLOAD] ");
        else if (test_bit(IPS_OFFLOAD_BIT, &ct->status))
                seq_puts(s, "[OFFLOAD] ");
        else if (test_bit(IPS_ASSURED_BIT, &ct->status))
                seq_puts(s, "[ASSURED] ");

Previously, in order to be offloaded, it had to be Assured. But not
anymore after this patchset. Thoughts?

Hi Marcelo,

I know that for some reason offloaded entries no longer display
'assured' flag in the dump. This could be changed, but I don't have a
preference either way and this patch set doesn't modify the behavior.
Up to you and maintainers I guess.

BTW after checking the log I don't think the assumption that all
offloaded connections are always assured is true. As far as I understand
act_ct originally offloaded established connections and change to
offload assured was made relatively recently in 43332cf97425
("net/sched: act_ct: Offload only ASSURED connections") without
modifying the prints you mentioned.

Oh. Somehow this behavior glued to my mind as it was always there. Not
sure which glue was used, please don't ask :D
Thanks!

Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>