[libvirt] [PATCH libvirt master] interface type: add udp socket support

[Jonathan Toppins]

On 8/10/15 1:28 AM, Laine Stump wrote:
> On 08/07/2015 06:14 PM, Jonathan Toppins wrote:
>> Adds a new interface type using UDP sockets, this seems only applicable
>> to QEMU but have edited tree-wide to support the new interface type.
>>
>> The interface type required the addition of a "destaddr" (destination
>> address), this then maps into the following xml and qemu call.
>>
>> <interface type='udp'>
>> 	<mac address='52:54:00:5c:67:56'/>
>> 	<source address='127.0.0.1' port='11112'/>
>> 	<model type='virtio'/>
>> 	<dest address="127.0.0.1' port='22222'/>
>
> I think I don't like the "dest" element. Historically, <source> has been
> used to describe the resources used in the real world to backup the
> emulated device, or maybe "the real world source of the data that's
> going into the emulated device". What you're doing is kind of redefining
> it to be "the local end of real world resources". Aside from that, for
> mcast, client, and server interface types, <source address....> is where
> the remote address for the socket is set.
>
> I'd say that to make it fit in better with the existing types, the
> remote address should be in <source address='blah'>, and the local
> address should be a subelement of that, something like:
>
>       <source address='remoteaddr' port='remoteport'>
>         <local address='localaddr' port='localport'/>
>       </source>
>
> That makes source address exactly fit the same purpose as source address
> for the existing mcast, server, and client interface types. (It may seem
> a little odd until you start thinking of "source" as "the thing farthest
> away from the virtual machine").

I am not partial to "dest", would be happy to change the tag to 
something that makes more sense.

Would need to think about (or be given some pointers to) how one would 
process a nested entry like this. Am sure it is "simple" but didn't 
really look much into it and followed what the surrounding code had done.

 From a, I need to generate this by hand or edit it by hand, it would 
make sense to me to keep the nesting in the <interface> entry as simple 
as possible, it seems right now it is only one tag level deep (limited 
knowledge though). On the other hand nesting it like this would make 
writing a DTD/XSD easier, not sure if libvirt does this for its xml 
configurations.

Thanks for the comments so far.