On Wed, 22 Jul 2026 11:00:07 -0700 Stanislav Fomichev wrote: > > > This is about current drivers that only report UNNECESSARY with xdp: the > > > xdp > > > prog has to maintain in-packet checksum if it changes the payload. I think > > > it's a fair assumption? > > > > What about decap? If we decap the header that device validated > > as UNNECESSARY there's no possibility of maintaining the checksum > > (by which IIUC you mean correcting it in along the payload changes). > > > > I think we'd need some API to "decrement the csum level" ? > > Or some heuristic in the drivers to decrement if the head moved > > by at least len(IP+UDP) into the packet ? > > True :-/ I guess one more case to document?
What would we be documenting? That it's a known bug and we have no idea how to address it? Or am I missing something? Again: .. the ask was to sketch out the plan of explicitly updating/invalidating the checksum even if we don't implement it today
