On Wed, 22 Jul 2026 11:00:07 -0700 Stanislav Fomichev wrote:
quoted
quoted
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