On Sun, 30 Jul 2023 09:13:02 -0400 Willem de Bruijn wrote: > > > This levels business is an unfortunate side effect of > > > CHECKSUM_UNNECESSARY. For a packet with multiple checksum fields, what > > > does the boolean actually mean? With these levels, at least that is > > > well defined: the first N checksum fields. > > > > If I understand this correctly this is intel specific feature that > > other NICs don't have. skb layer also doesn't have such concept. > > The driver should say CHECKSUM_UNNECESSARY when it's sure > > or don't pretend that it checks the checksum and just say NONE. > > I did not know how much this was used, but quick grep for non constant > csum_level shows devices from at least six vendors. I thought it was a legacy thing from early VxLAN days. We used to leave outer UDP csum as 0 before LCO, and therefore couldn't convert outer to COMPLETE, so inner could not be offloaded/validated. Should not be all that relevant today.
