# Re: \[PATCH net-next v2 0/8\] Introduce conntrack offloading to the nfp driver

- From: Marcelo Ricardo Leitner \<hidden\>
- Date: 2021-05-31 18:20:54 
- List: netdev
- Page: https://ratatoskr.run/netdev/2021/05/11204231
- Thread: https://ratatoskr.run/netdev/2021/05/11204216/t.md

```text
On Mon, May 31, 2021 at 02:45:59PM +0200, Simon Horman wrote:
> Louis Peens says:
>
> This is the first in a series of patches to offload conntrack
> to the nfp. The approach followed is to flatten out three
> different flow rules into a single offloaded flow. The three
> different flows are:
>
> 1) The rule sending the packet to conntrack (pre_ct)
> 2) The rule matching on +trk+est after a packet has been through
>    conntrack. (post_ct)

I think this part (matching on +trk+est) was left to another series,
but anyway, supporting only +trk+est is not very effective, btw.
+rpl/-rpl is also welcomed.

> 3) The rule received via callback from the netfilter (nft)
>
> In order to offload a flow we need a combination of all three flows, but
> they could be added/deleted at different times and in different order.
>
> To solve this we save potential offloadable CT flows in the driver,
> and every time we receive a callback we check against these saved flows
> for valid merges. Once we have a valid combination of all three flows
> this will be offloaded to the NFP. This is demonstrated in the diagram
> below.
>
> 	+-------------+                      +----------+
> 	| pre_ct flow +--------+             | nft flow |
> 	+-------------+        v             +------+---+
> 	                  +----------+              |
> 	                  | tc_merge +--------+     |
> 	                  +----------+        v     v
> 	+--------------+       ^           +-------------+
> 	| post_ct flow +-------+       +---+nft_tc merge |
> 	+--------------+               |   +-------------+
> 	                               |
> 	                               |
> 	                               |
> 	                               v
> 	                        Offload to nfp

Sounds like the offloading of new conntrack entries is quite heavy
this way. Hopefully not.

>
> This series is only up to the point of the pre_ct and post_ct
> merges into the tc_merge. Follow up series will continue
> to add the nft flows and merging of these flows with the result
> of the pre_ct and post_ct merged flows.
>
> Changes since v1:
> - nfp: flower-ct: add ct zone table
>     Fixed unused variable compile warning
>     Fixed missing colon in struct description
>
> Louis Peens (8):
>   nfp: flower: move non-zero chain check
>   nfp: flower-ct: add pre and post ct checks
>   nfp: flower-ct: add ct zone table
>   nfp: flower-ct: add zone table entry when handling pre/post_ct flows
>   nfp: flower-ct: add nfp_fl_ct_flow_entries
>   nfp: flower-ct: add a table to map flow cookies to ct flows
>   nfp: flower-ct: add tc_merge_tb
>   nfp: flower-ct: add tc merge functionality
>
>  drivers/net/ethernet/netronome/nfp/Makefile   |   3 +-
>  .../ethernet/netronome/nfp/flower/conntrack.c | 486 ++++++++++++++++++
>  .../ethernet/netronome/nfp/flower/conntrack.h | 155 ++++++
>  .../net/ethernet/netronome/nfp/flower/main.h  |   6 +
>  .../ethernet/netronome/nfp/flower/metadata.c  | 101 +++-
>  .../ethernet/netronome/nfp/flower/offload.c   |  31 +-
>  6 files changed, 775 insertions(+), 7 deletions(-)
>  create mode 100644 drivers/net/ethernet/netronome/nfp/flower/conntrack.c
>  create mode 100644 drivers/net/ethernet/netronome/nfp/flower/conntrack.h
>
> --
> 2.20.1
>

```