svn commit: r327559 - in head: . sys/net

[Eugene Grosbein]

05.01.2018 4:52, Steven Hartland wrote:

>> RSS by definition has meaning to received stream. What is "outbound" stream
>> in this context, why can the hash calculatiom method change and what exactly
>> does it mean "a stream being incorrectly split"?
> Yes RSS is indeed a received stream but that is used by lagg for lacp and loadbalance protocols
> to decide which port of the lagg to "send" the packet out of.
> As the flowid is not known when a new "output" stream is instigated the current code 
> falls back to manual hash calculation to determine which port to send the initial packet from.
> Once a response is received a tx then uses the flowid.
> This change of hash calculation method can result in the initial packet being sent
> from a different port than the rest of the stream; this is what I meant by "incorrectly split".
> 
> See the following:
> https://github.com/freebsd/freebsd/blob/master/sys/net/if_lagg.c#L2066
> https://github.com/freebsd/freebsd/blob/master/sys/net/ieee8023ad_lacp.c#L846

I still do not get what is "output stream" for you.

If you are talking on forwarding (routing) transit packets at IP layer,
they all have flowid from the beginning and first packet does not differ from others at all.

If you are talking on locally originated (not transit) data streem from local TCP socket
being sent in response to corresponding incoming TCP segments, then these outgoing
packets should have their own fixed flow id by default in case of LACP
and thhis flow id should not depend on (possibly ever changing) flow id of incoming TCP segments.

If you insist that flow id of outgoing packets does depend on ever changing incoming packet's flow id,
then this is the bug that should be fixed and not lagg's defaults.