On 03/05/2012 11:14 AM, Eric Blake wrote:
On 03/05/2012 09:05 AM, Laine Stump wrote:
This patch is in response to:
https://bugzilla.redhat.com/show_bug.cgi?id=798467
If a guest's tap device is created using the same MAC address the guest uses for its own network card (which connects to the tap device), the Linux kernel will log the following message and traffic will not pass:
kernel: vnet9: received packet with own address as source address
This patch disallows MAC addresses with a first byte of 0xFE, but only in the case that the MAC address is used for a guest interface that's connected by way of a standard tap device. (In other words, the validation is done at runtime at the same place the MAC address is modified for the tap device, rather than when mac address is parsed, the idea being that it is then we know for sure the address will be problematic.) --- src/util/virnetdevtap.c | 22 ++++++++++++++++++++-- 1 files changed, 20 insertions(+), 2 deletions(-) ACK.
Thanks. I recieved the additional info that this was discovered not by someone manually setting the mac address to fe:xx:xx:xx:xx:xx in some ill-informed attempt to match what they saw in the tap device's ifconfig output, but because a management application automatically chose an address that started with 0xFE. I'm waiting to push until I hear back whether or not that management application can be configured to *not* do that.