RE: [Xen-devel] Stimulating domains to send gratuitous ARPs

["Ian Pratt" <Ian.Pratt@xxxxxxxxxxxx>]

> There are existing tools for sending arps -- the problem is knowing what
> IP address to use in the ARP -- it's actually pretty hard to know this
> in Dom0 (which is where you know that the ARP needs to be sent) and if
> you install it in DomU you need a way to kick the domain to actually
> call the utility... (plus you have to install a service in DomU which is
> something I think is a bad idea to require).
> 
> Whilst I might agree that from a purist point of view having netfront do
> this is a violation of layering, it's already accepted in some other
> upstream drivers 

It's pretty clear it's not going to be accepted in the netfront that goes into 
upstream Linux, at least not without sedating various LKML folk first :)

For bond case you described, you don't need to send ARPs, you just need to send 
any packet with the right src MAC to cause the switches to reconfigure. Since 
the bond driver likely already maintains a list of MAC addrs its operating on 
behalf of this is easy.

Ian


> Simon
> 
> > -----Original Message-----
> > From: Ian Campbell [mailto:Ian.Campbell@xxxxxxxxxxxxx]
> > Sent: Thursday, July 05, 2007 3:46 PM
> > To: Graham, Simon
> > Cc: xen-devel@xxxxxxxxxxxxxxxxxxx
> > Subject: Re: [Xen-devel] Stimulating domains to send gratuitous ARPs
> >
> > On Thu, 2007-07-05 at 14:41 -0400, Graham, Simon wrote:
> > > I accept that this is not very nice and we should probably have a
> > more
> > > organized/documented way to do this but Iâm not sure what would be
> > > appropriate; any suggestions?
> >
> > A usespace tool to send such an ARP would be a very useful thing to
> > have, if it doesn't already exist.
> >
> > The gratuitous arping in netfront is not very popular with the
> upstream
> > Linux folks so this functionality is not in the paravirt_ops patches
> > which are going upstream, so we'd need such a tool in the end anyway.
> >
> > Ian.
> >
> >
> >
> >

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel