[libvirt] [PATCH v2 1/4] virInterface: Expose link state & speed

[Daniel P. Berrange]

On Wed, Jun 11, 2014 at 11:19:14AM +0200, Michal Privoznik wrote:
> On 11.06.2014 03:13, John Ferlan wrote:
> >
> >
> >On 06/05/2014 11:39 AM, Michal Privoznik wrote:
> >>Currently it is not possible to determine the speed of an interface
> >>and whether a link is actually detected from the API. Orchestrating
> >>platforms want to be able to determine when the link has failed and
> >>where multiple speeds may be available which one the interface is
> >>actually connected at. This commit introduces an extension to our
> >>interface XML (without implementation to interface driver backends):
> >>
> >>   <interface type='ethernet' name='eth0'>
> >>     <start mode='none'/>
> >>     <mac address='aa:bb:cc:dd:ee:ff'/>
> >>     <link speed='1000' state='up'/>
> >>     <mtu size='1492'/>
> >>     ...
> >>   </interface>
> >>
> >>Where @speed is negotiated link speed in Mbits per second, and state
> >>is the current NIC state (can be one of the following:  "unknown",
> >>"notpresent", "down", "lowerlayerdown","testing", "dormant", "up").
> >>
> >>Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
> >>---
> >>  docs/schemas/basictypes.rng                     | 25 ++++++++++
> >>  docs/schemas/interface.rng                      |  1 +
> >>  src/conf/device_conf.c                          | 62 +++++++++++++++++++++++++
> >>  src/conf/device_conf.h                          | 27 ++++++++++-
> >>  src/conf/interface_conf.c                       | 11 ++++-
> >>  src/conf/interface_conf.h                       |  2 +
> >>  src/libvirt_private.syms                        |  4 ++
> >>  tests/interfaceschemadata/bridge-no-address.xml |  1 +
> >>  tests/interfaceschemadata/bridge.xml            |  1 +
> >>  tests/interfaceschemadata/ethernet-dhcp.xml     |  1 +
> >>  10 files changed, 133 insertions(+), 2 deletions(-)
> >>
> >
> >Already been ACK'd, but I will point out the interface.html.in hasn't
> >been updated - later you update the nodedev.html.in file - so probably
> >reasonable to do so again. While at it the consistency of using "Mbits"
> >vs. "Mb" in the comment in device_conf.h
> 
> The first issue has simple explanation - there's no interface.html.in yet.
> Yes we lack the virInterface XML documentation. The second one I'm fixing
> prior to push.
> 
> >
> >Just so I understand - the reality is regardless of what the XML is on
> >input - the code will still check/get/set the link state/speed - so this
> >is mostly an output thing.
> 
> Yes. So far this is only for getting the link speed & state. Which brings up
> an interesting question. With recent issue with QoS on bridgeless networks
> on mind - should we make virInterface XML parsing actually reject any
> <link/> since it's output element only? One could argue that we usually
> ignore unknown elements, but then <link/> is not unknown element anymore.
> One way or another, it can be done in a separate patch.

Apps must always be able to round-trip XML. ie they should be able to
do DumpXML and then feed that back into DefineXML and have no functional
change. Thus we must not reject <link/> with an error when parsing, we
must ignore it or honour it as appropriate for the desired semantics.


Regards,
Daniel
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