Hi Marcus, On 1/14/25 17:47, Marcus Wichelmann wrote: > Am 12.02.24 um 15:35 schrieb Florian Kauer: >> On 12.02.24 14:41, Toke Høiland-Jørgensen wrote: >>> Florian Kauer <florian.kauer@xxxxxxxxxxxxx> writes: >>> >>>> 2. For the RX side, the metadata is documented as "XDP RX Metadata" >>>> (https://docs.kernel.org/networking/xdp-rx-metadata.html), while for >>>> TX it is "AF_XDP TX Metadata" >>>> (https://www.kernel.org/doc/html/next/networking/xsk-tx-metadata.html). >>>> That seems to imply that TX metadata only works for AF_XDP, but not >>>> for direct redirection. Is there a reason for that? >>> >>> Well, IIRC, AF_XDP was the most pressing use case, and no one has gotten >>> around to extending this to the regular XDP forwarding path yet. >> >> Ok, that is fine. I had the fear that there is some fundamental problem >> that prevents to implement this. > > Hi, > are there any updates on this? I'm currently looking into this as well. I am still interested, but have no implementation planned short- or mid-term. So, looking forward to your implementation :-) Greetings, Florian > > I'd like to have a way to enable the TX checksum offload when redirecting from > one device to another. > Stanislav Fomichev already implemented [1] the TX offload support for the AF_XDP > use case (thanks for that), but for now, this cannot be used for "regular" > redirects. > > I'm currently in a position where I can invest some work into this, but figured > it would make sense to ask you first: > > Do you already have concrete plans or ideas in mind, how the API to trigger the > TX offloads should look like? > I have seen the talk [2] from Jesper about this, but I'm not sure if the > proposals in there are still up to date. > > I think it could be possible to introduce a program flag, just like > `BPF_F_XDP_HAS_FRAGS`, and if this flag is set, interpret a part of the > metadata area as a `struct xsk_tx_metadata`. Then, the code to apply the > offloads from that struct when xmit-ing the frame could be reused, as it > is already implemented in `mlx5e_xmit_xdp_frame` for example. > But the "xsk" in the struct name may be a bit confusing. :/ > > Do you think this could work or could you guide me into a direction that may > have a chance to be upstreamable? Also, is there any recent work on this that > I should know off? > > Thanks! > > Marcus Wichelmann > Hetzner Cloud GmbH > > [1] https://lore.kernel.org/bpf/20231127190319.1190813-3-sdf@xxxxxxxxxx/ > [2] https://lpc.events/event/16/contributions/1362/attachments/1056/2017/xdp-hints-lpc2022.pdf >
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