This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
Home Products Support Community News


Re: [Xen-users] xen network interfaces: How do I retrieve from an execu

To: Kay Schubert <kayegypt@xxxxxx>
Subject: Re: [Xen-users] xen network interfaces: How do I retrieve from an executable running within domain0 the MAC of an frontend-(domainU)-network-interface ?
From: "Fajar A. Nugraha" <fajar@xxxxxxxxx>
Date: Sun, 23 Aug 2009 21:37:25 +0700
Cc: xen-users@xxxxxxxxxxxxxxxxxxx
Delivery-date: Sun, 23 Aug 2009 07:38:06 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <200908231322.48688.kayegypt@xxxxxx>
List-help: <mailto:xen-users-request@lists.xensource.com?subject=help>
List-id: Xen user discussion <xen-users.lists.xensource.com>
List-post: <mailto:xen-users@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=unsubscribe>
References: <200908231322.48688.kayegypt@xxxxxx>
Sender: xen-users-bounces@xxxxxxxxxxxxxxxxxxx
On Sun, Aug 23, 2009 at 6:22 PM, Kay Schubert<kayegypt@xxxxxx> wrote:
> Now each of those backend-interfaces gets assigned the
> infamous FE:FF:FF:FF:FF:FF MAC. That turns out to be a problem if I try to
> send packets from domain0 through the bridge-interface to any of the domainU
> instances: the log tells me something along "ethernet source and target are
> equal, can't send packets to myself".

I had that problem on some dom0s as well :)
Interestingly it doesn't occur when I split dom0 and domUs traffic on
separate physical interfaces. For example :
- eth0 for dom0's IP address
- eth1 setup as trunk, created vlans and bridge on top of vlans, no IP
address on those bridges, with domU using the bridges.

> However, I had some success when I
> manually assigned (by calling at domain0, for instance, "ip link set vif13.1
> address 00:16:3E:7D:D0:98") the MAC assigned to the
> frontend-(domainU)-interface to the backend-(domain0)-interface as well.

Actually, it doesn't matter what MAC you assign to the vif, as long as
it's unique. At least that was the case on my setup. So I simply
modify /etc/xen/scripts/vif-bridge, and generate a random MAC for
every vif. It's not the same as domU's MAC.

> Now my question is: Supposed an executable is running within domain0, and this
> executable has been handed the name of a Xen backend interface, is there a
> way to obtain the MAC of the associated frontend-(domainU)-interface ?

If you still need domU's mac (for any reason), you could try this
- xm network-list 13
- xenstore-ls /local/domain/13/device/vif

where "13" in that example is domU's ID. You could usually find out
domU id from vif name (in your case vif13.1). I haven't tried running
it from vif-bridge script though.


Xen-users mailing list

<Prev in Thread] Current Thread [Next in Thread>