[ovs-dev] [PATCH v4] Add configurable OpenFlow port name.

[Ben Pfaff]

On Tue, May 24, 2016 at 03:07:23PM +0800, Xiao Liang wrote:
> Add new column "ofname" in Interface table to configure port name reported
> to controllers with OpenFlow protocol, thus decouple OpenFlow port name from
> device name.
> 
> For example:
>     # ovs-vsctl set Interface eth0 ofname=wan
>     # ovs-vsctl set Interface eth1 ofname=lan0
> then controllers can recognize ports by their names.
> 
> Signed-off-by: Xiao Liang <shaw.leon at gmail.com>
> ---
> v2: Added test for ofname
>     Increased db schema version
>     Updated NEWS
> v3: Rebase
> v4: Rebase
>     Move prototypes in ofproto/ofproto.h to correct section

Thanks for the patch!  I think that this is a reasonable approach.

I'd like ovs-ofctl to report an error if a user attempts to refer to a
port by name but there is more than one port with the name.  That could
be in a separate patch.

The logic in ofproto_port_set_ofpname() does not make sense to me in the
third case here:

    if (!devname ||
        (ofp_name && !strncmp(ofp_name, ofport->pp.name, name_size - 1)) ||
        (!ofp_name && !strncmp(devname, ofport->pp.name, name_size - 1))) {
        /* No need to change port name. */
        return;
    }

I believe that in the
        (!ofp_name && !strncmp(devname, ofport->pp.name, name_size - 1))) {
case, we should remove any current ofp_name and change the name of the
OpenFlow port back to the device name, but instead the code appears to
do nothing.

It is too bad that the ofp_names smap exists at all.  It seems that it
should be possible to simply represent the ofp_name inside the ofport,
without the need for a separate map.

It would be a good idea to mention the possibility of duplicate names in
the documentation in vswitch.xml.

Thanks,

Ben.