> On Mar 22, 2017, at 2:54 PM, Michael Ben-Ami via discuss > <[email protected]> wrote: > > We have a flow that looks like this: > > priority=1030,icmp6,in_port=4,icmp_type=135,nd_target=xxxx:xxxx:1:d0::1105:3000/124 > actions=resubmit(,25) > > When neighbor solicitations come in on port 4 (ethernet interface), we can > see them in tcpdump as having the correct nd_target, yet the flow's n_byte, > and n_packet counters don't increase, and we confirm the packet falls to a > lower priority matching flow (that drops). However, if we remove the > nd_target field from the match, the solicitation hits the flow as expected, > every time. > > As another wrinkle, while receiving continuous neighbor solicitations, we > simply re-add the above flow in a loop, like "while true; do ovs-ofctl > add-flow...; done". And without fail, the flow will suddenly instantly be hit > (n_byte and n_packet counters increase, VM actually receives solicitation), > with no change at all on what's been coming in on the data plane, and no > change to the content of the flow set as a whole.
Strange. You might try running "ovs-dpctl dump-flows" in a loop and see if an appropriate flow is being pushed to the kernel datapath and getting hit. The behavior you've described makes me wonder if re-adding the flow is causing the packet to execute in userspace, which is properly handling the packet, and then a kernel flow is pushed down that no longer works. > For a similar wrinkle, we can also make the flow hit by simply repeatedly > running tcpdump on the interface multiple times. Like if port 4 is eth1, > we'll just do "tcpdump -enni eth1" multiple times, and the solicitation will > be successfully received by VM, counters increase, etc. That just sounds odd. I can't imagine why that would matter. > Any ideas on why this may be? It's seems like a race condition somewhere that > is relevant to matching on nd_target. > > Other info: > > # ovs-ofctl --version > ovs-ofctl (Open vSwitch) 2.5.0 I haven't looked to see if this kind of issue has been addressed, but is there a reason you're not running something more recent? The 2.5 series is now at 2.5.2. --Justin _______________________________________________ discuss mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-discuss
