[ovs-dev] [ovs-discuss] [ACLv2 06/19] ofproto: Add flow expiration callback.

Ben Pfaff blp at nicira.com
Fri Sep 4 22:05:44 UTC 2009

Jesse Gross <jesse at nicira.com> writes:

> This is a very good catch as there are several tricky corner cases
> here.  In addition to the cases you mention, there were also similar
> conditions involving revalidation.  The ACL code is not very forgiving
> of incorrect flow expiration messages: both missing and overly
> aggressive expirations will lead to incorrect stats.  So if I trigger
> flow_expire_cb() in ofproto_send_packet() after it sent a packet that
> happens to match a still-active flow, then that flow will have the
> wrong stats.  What I do now is pass an additional flag saying that the
> flow will not ever be installed.  This causes the stats to be credited
> immediately for that packet and then there is no need to send a flow
> expiration message later.

This sounds much better, thank you.

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