Thanks！
Ilya Maximets <i.maxim...@ovn.org>于2023年8月15日 周二02:02写道：
> On 8/14/23 04:37, Peng He wrote:
> > OVS allows overlapping megaflows, as long as the actions of these
> > megaflows are equal. However, the current implementation of action
> > modification relies on flow_lookup instead of ufid, this could result
> > in looking up a wrong megaflow and make the ukeys and megaflows
> inconsistent
> >
> > Just like the test case in the patch, at first we have a rule with the
> > prefix:
> >
> > 10.1.2.0/24
> >
> > and we will get a megaflow with prefixes 10.1.2.2/24 when a packet with
> IP
> > 10.1.2.2 is received.
> >
> > Then suppose we change the rule into 10.1.0.0/16. OVS prefers to keep
> the
> > 10.1.2.2/24 megaflow and just changes its action instead of extending
> > the prefix into 10.1.2.2/16.
> >
> > then suppose we have a 10.1.0.2 packet, since it misses the megaflow,
> > this time, we will have an overlapping megaflow with the right prefix:
> > 10.1.0.2/16
> >
> > now we have two megaflows:
> > 10.1.2.2/24
> > 10.1.0.2/16
> >
> > last, suppose we have changed the ruleset again. The revalidator this
> > time still decides to change the actions of both megaflows instead of
> > deleting them.
> >
> > The dpif_netdev_flow_put will search the megaflow to modify with unmasked
> > keys, however it might lookup the wrong megaflow as the key 10.1.2.2
> matches
> > both 10.1.2.2/24 and 10.1.0.2/16!
> >
> > This patch changes the megaflow lookup code in modification path into
> > relying the ufid to find the correct megaflow instead of key lookup.
> >
> > Fixes: beb75a40fdc2 ("userspace: Switching of L3 packets in L2 pipeline")
> > Signed-off-by: Peng He <hepeng.0...@bytedance.com>
> > ---
> > lib/dpif-netdev.c | 45 ++++++++++++++++++++++++++++++---------------
> > tests/pmd.at | 47 +++++++++++++++++++++++++++++++++++++++++++++++
> > 2 files changed, 77 insertions(+), 15 deletions(-)
>
> Thanks! Applied and backported down to 2.17.
>
> Best regards, Ilya Maximets.
>
--
hepeng
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