Re: [libvirt] [RFC] Allowing promiscuous mode for domains network interfaces
On Monday 02 July 2012 19:14:04 Eric Blake wrote:
On 07/02/2012 09:28 AM, Jean-Baptiste Rouault wrote:
> Hi all,
>
> By default, OpenVZ and VirtualBox (> 4.0.x) filter network packets by MAC
> addresses : only broadcast, multicast and packets directly targeted to
> VMs are transmitted.
> This behaviour prevents from using promiscuous mode inside domains.
>
> I'd like to write some patches to disable these filters from libvirt.
> Would it be ok to modify OpenVZ and VirtualBox drivers so that they
> disable the filters by default ?
>
> If this is not acceptable, what about making it configurable through
> domains' XML ?
It sounds like exposing this through the domain XML would be useful to
other hypervisors, and certainly something that I would rather have
configurable per-guest instead of hard-coded to one default or another.
We might declare that if the XML element is not present then it is up
to hypervisor defaults whether the interface is promiscuous, to allow
for back-compat, while still allowing the user to explicitly select
narrow or promiscuous with new libvirt.
Ok, so what about adding a "promiscuouspolicy" attribute to the
"interface"
tag ?
There are currently 3 possible values with VirtualBox :
- Deny
- AllowNetwork : allow promiscuous mode but restrict its scope to the internal
network
- AllowAll
So we could create a virDomainNetPromiscuousPolicy enum with these 3 values
for a start.
Regards
--
Jean-Baptiste ROUAULT
Ingénieur R&D - diateam : Architectes de l'information
Phone : +33 (0)2 98 050 050 Fax : +33 (0)2 98 050 051