>> Isn't a symmetric hashing for af-packet something very fundamental?
>> Looks much more like a bug to me.
>
>
> I agree it would be useful resp. fundamental. I'm not quite sure whether
> PACKET_FANOUT_HASH always had this guarantee since the initial
> implementation
It is based on rxhash, which is intended to have this property. See for
instance the commit messages from commit b249dcb82d32 ("rps:
consistent rxhash")
"In case we compute a software skb->rxhash, we can generate a
consistent hash : Its value will be the same in both flow directions."
commit 6862234238e8 ("net: small bug on rxhash calculation") also
explicitly refers to this property.
> f.e. depending on whether the skb got fanout demuxed from RX or TX paths,
> you would either use a hw hash or it would have gone through the kernel's
> (predecessor) flow dissector
It's quite possible that not all hardware hash implementations do the
right thing, indeed.
