Re: [Xen-devel] [RFC v2 4/4] xen-netback: skip IPv4 and IPv6 interfaces

From: Zoltan Kiss
Date: Mon Feb 17 2014 - 09:37:30 EST


There is a valid scenario to put IP addresses on the backend VIFs:

http://wiki.xen.org/wiki/Xen_Networking#Routing

Also, the backend is not necessarily Dom0, you can connect twou guests with backend/frontend pairs.

Zoli

On 15/02/14 02:59, Luis R. Rodriguez wrote:
From: "Luis R. Rodriguez" <mcgrof@xxxxxxxx>

The xen-netback driver is used only to provide a backend
interface for the frontend. The link is the only thing we
use, and that is used internally for letting us know when the
xen-netfront is ready, when it switches to XenbusStateConnected.

Note that only when the both the xen-netfront and xen-netback
are both in state XenbusStateConnected will xen-netback allow
userspace on the host (backend) to bring up the interface. Enabling
and disabling the interface will simply enable or disable NAPI
respectively, and that's used for IRQ communication set up with
the xen event channels.

Cc: Paul Durrant <Paul.Durrant@xxxxxxxxxx>
Cc: Ian Campbell <ian.campbell@xxxxxxxxxx>
Cc: Wei Liu <wei.liu2@xxxxxxxxxx>
Cc: xen-devel@xxxxxxxxxxxxxxxxxxxx
Cc: netdev@xxxxxxxxxxxxxxx
Signed-off-by: Luis R. Rodriguez <mcgrof@xxxxxxxx>
---
drivers/net/xen-netback/interface.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index d380e3f..07e6fd2 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -351,7 +351,7 @@ struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,

eth_hw_addr_random(dev);
memcpy(dev->dev_addr, xen_oui, 3);
- dev->priv_flags |= IFF_BRIDGE_NON_ROOT;
+ dev->priv_flags |= IFF_BRIDGE_NON_ROOT | IFF_SKIP_IP;
netif_napi_add(dev, &vif->napi, xenvif_poll, XENVIF_NAPI_WEIGHT);

netif_carrier_off(dev);


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