[ovs-discuss] Set metadata field

[Liran Schour]

Ben Pfaff <blp at nicira.com> wrote on 21/03/2013 09:52:24 PM:

> On Thu, Mar 21, 2013 at 09:07:08AM +0200, Liran Schour wrote:
> >
> > I try to pass metadata to the controller through the following flow:
> >    ovs-ofctl add-flow br-int "in_port=5 priority=2
actions=set_field:123->
> >    metadata,controller(reason=no_match)"
> >
> > I do see the following flow when I do dump-flows:
> >    cookie=0x0, duration=310.921s, table=0, n_packets=0, n_bytes=0,
> >    idle_age=310, priority=2,in_port=5 actions=load:0x7b->
OXM_OF_METADATA
> >    [],controller(reason=no_match)
> >
> > But when I check in the controller side I see metadata=0.
> > I check the metadata value with 2 different methods:
> >    1. By snooping the communication between switch to controller and
see
> >    metadata=0.
> >    2. By using the extract_flow function inside the controller to
retrieve
> >    the flow
> >     corresponding to the packet_in message.
> >
> > What am I doing wrong here?
>
> I don't know.
>
> I set up a test of my own with Open vSwitch from current "master".  I
> added a single flow to the switch, with:
>     ovs-ofctl add-flow br0 'actions=load:123->OXM_OF_METADATA
> [],controller,normal'
> Then I set up a simple "controller" to watch for packet-ins:
>     ovs-ofctl monitor -P nxm br0 128
> When I run packets through the switch, I see the metadata fields set
> as I would expect in the packet-ins, e.g.
>     NXT_PACKET_IN (xid=0x0): total_len=42 in_port=1 metadata=0x7b
> (via action) data_len=42 (unbuffered)
>

When I try to monitor the messages between switch to controller through
ovs-ofctl monitor
I do see NXT_PACKET_IN packets with metadata=0x7b but when I try to monitor
the messages through
ovs-ofctl snoop I do see OFPT_PACKET_IN packets with metadata=0.
How can I know which is the real type of the message that goes on the wire?
( OFPT_PACKET_IN or NXT_PACKET_IN )
When I try to verify it inside the code of ovs-controller it seems that it
gets OFPT_PACKET_IN packet with metadata equals to zero.
Is it possible to pass metadata value with OFPT_PACKET_IN packet?
Why I can not see that?

Thanks,
- Liran