On Thu, Oct 23, 2025 at 09:29:28PM -0400, Jon Maloy wrote:
ARP announcements and unsolicited NAs should be handled with caution because of the risk of malignant users emitting them to disturb network communication.
There is however one case we where we know it is legitimate and safe for us to send out such messages: The one time we switch from using ctx->own_tap_mac to a MAC address received via the recently added neigbour subscription function. Later changes to the MAC address of a host in an existing entry cannot be fully trusted, so we abstain from doing it in such cases.
When sending this type of messages, we notice that the guest accepts the update, but shortly later asks for a confirmation in the form of a regular ARP/NS request. This is responded to with the new value, and we have exactly the effect we wanted.
This commit adds this functionality.
Signed-off-by: Jon Maloy
Reviewed-by: David Gibson