On 01.12.2016 00:39, Erik Nordmark wrote:
> Implemented RFC7527 Enhanced DAD.
> IPv6 duplicate address detection can fail if there is some temporary
> loopback of Ethernet frames. RFC7527 solves this by including a random
> nonce in the NS messages used for DAD, and if an NS is received with the
> same nonce it is assumed to be a looped back DAD probe and is ignored.
> RFC7527 is enabled by default. Can be disabled by setting both of
> conf/{all,interface}/enhanced_dad to zero.
>
> Signed-off-by: Erik Nordmark <nordm...@arista.com>
> Signed-off-by: Bob Gilligan <gilli...@arista.com>
> ---
Reviewed-by: Hannes Frederic Sowa <han...@stressinduktion.org>
Thanks!
> @@ -794,6 +808,17 @@ static void ndisc_recv_ns(struct sk_buff *skb)
> have_ifp:
> if (ifp->flags & (IFA_F_TENTATIVE|IFA_F_OPTIMISTIC)) {
> if (dad) {
> + if (nonce != 0 && ifp->dad_nonce == nonce) {
> + u8 *np = (u8 *)&nonce;
> + /* Matching nonce if looped back */
> + ND_PRINTK(2, notice,
> + "%s: IPv6 DAD loopback for
> address %pI6c nonce %02x:%02x:%02x:%02x:%02x:%02x ignored\n",
> + ifp->idev->dev->name,
> + &ifp->addr,
> + np[0], np[1], np[2], np[3],
> + np[4], np[5]);
> + goto out;
> + }
> /*
> * We are colliding with another node
> * who is doing DAD
>
I think it could be a "%pM" because it looks like a MAC address, but
better leave it like that. :)
Bye,
Hannes
