I sent out a patch that should fix this:
http://openvswitch.org/pipermail/dev/2014-December/049972.html
It will take some time, probably a few days, for it to get into the
kernel and the OVS tree's kernel module. After that, I think you'll be
ready to go. (However, the buggy behavior will still be present if a
user upgrades userspace without upgrading their kernel module. I doubt
that that is really a big deal though.)
On Thu, Dec 11, 2014 at 12:36:51AM +0900, Motonori Shindo wrote:
> Ben and Jesse,
>
> Thanks for picking this issue up.
>
> Although current behavior is not consistent in VLAN and no-VLAN cases, as far
> as NetFlow concerns it doesn’t matter in fact because NetFlow only counts L3
> packet size anyway.
>
> Here’s the story. First, I wanted to fix an issue that OVS currently reports
> L2 packet size, not L3 packet size in NetFlow flow records (NetFlow should
> report L3 packet size). I thought the easiest way to fix this problem was to
> subtract the ethernet header length when reporting a NetFlow flow record.
> Then, I realized that I should also take VLAN header into account if it is
> present. I checked how NetFlow behaves in VLAN case and no-VLAN case and
> found out that OVS reports the same packet size in NetFlow regardless to the
> presence of VLAN header.
>
> Once this packet size issue related to VLAN header gets solved by someone
> else (as this is probably beyond of my understanding of the relevant code), I
> will work on fixing the L2 vs L3 packet size issue specifically in NetFlow.
>
> Regards,
>
> On 2014/12/09 3:22, "Jesse Gross" <[email protected]
> <mailto:[email protected]>> wrote:
>
> On Mon, Dec 8, 2014 at 9:58 AM, Ben Pfaff <[email protected]
> <mailto:[email protected]>> wrote:
> Motonori Shindo (CCed) reported to me recently that NetFlow does not
> include VLAN headers in the byte counts that it exports. Taking a
> look at the kernel datapath code, I see that ovs_flow_stats_update()
> accounts raw skb->len to byte counters. I suspect that it should add
> 4 if a VLAN header was present but removed by VLAN acceleration.
>
> Presumably we should also do this for port stats as well to be consistent.
>
>
>
> ---
> Motonori Shindo
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