On 15 May 2015 at 07:13, luc <mluc.2...@gmail.com> wrote: > 2015-05-12 23:20 GMT+02:00 Joe Stringer <joestrin...@nicira.com>: >> >> On 12 May 2015 at 11:59, luc <mluc.2...@gmail.com> wrote: >> > Hello team >> > >> > I am trying to work deeper into the code level of OVS. and what I would >> > like to do is the following: >> > >> > For the receiving packet, if there is no matching rule in the flow table >> > (i.e. packet is sent to user space and further sent to the sdn >> > controller), >> > I would like to print out a message; otherwise, if there is matching >> > rule, >> > print something else. >> > >> > So, in the code, I think datapath.c, ovs_dp_process_packet_with_key() >> > does >> > the trick, the refered code is as following. Then, what I did is to send >> > periodically the same kind of packet to the OVS machine (all the tested >> > machines are built in VMs). >> > >> > However, I see that whenever I send my packet in a bit slow-speed (e.g. >> > one >> > packet per 1 or 2 second), it always print out "flow entry is *NOT >> > *found", >> > but indeed, I can really confirm by command line that the respective >> > flow >> > entry (also by wireshark at sdn controller, there is no PktIn any more >> > for >> > these packets); But, when I send my packet a bit faster, e.g. one packet >> > per 0.5 second, then, I'm able to get the expected output message "flow >> > entry is found". >> > >> > Can anyone help me to explain why does that happen? and I pretty much >> > appreciate if you can point me into the right direction... >> >> ovs-vswitchd manages the kernel datapath flows based on a variety of >> factors including packet rate, so it's possible that at low packet >> rates the flow is evicted for some reason. Depending on the version of >> OVS, the logic of this differs, but you should be able to find it in >> ofproto/ofproto-dpif-upcall.c. You can also turn the 'dpif' logging up >> to debug level and observe flow adds/deletes in the ovs-vswitchd.log. > > > > Hi, > > Very appreciate your hints.. > > I searched around both in the code and also in Internet, and found one slide > as attachment.. one thing I am still confused is that: > > from the slide, it says "decision about how to process packet is made in > userspace", does it mean that whenever there is an incoming packet (no > matter it is the first one in a flow or not), it always first goes to the > user space ??? > > ps, the ovs version I am using is 2.3.1. > > Thanks a lot for some info.
The slide also says in two different places that only the first packet is required to make the decision, and that subsequent/following packets are handled in the datapath. _______________________________________________ dev mailing list dev@openvswitch.org http://openvswitch.org/mailman/listinfo/dev
