On Mon, 22 Aug 2011 15:23:48 -0400
"J. Bruce Fields" <bfields@xxxxxxxxxxxx> wrote:
> On Sat, Aug 20, 2011 at 06:24:29PM +0800, Mi Jinlong wrote:
> > For IPv6 local address, lockd can not callback to client for
> > missing scope id when binding address at inet6_bind:
> >
> > 324 if (addr_type & IPV6_ADDR_LINKLOCAL) {
> > 325 if (addr_len >= sizeof(struct sockaddr_in6) &&
> > 326 addr->sin6_scope_id) {
> > 327 /* Override any existing binding, if another one
> > 328 * is supplied by user.
> > 329 */
> > 330 sk->sk_bound_dev_if = addr->sin6_scope_id;
> > 331 }
> > 332
> > 333 /* Binding to link-local address requires an interface */
> > 334 if (!sk->sk_bound_dev_if) {
> > 335 err = -EINVAL;
> > 336 goto out_unlock;
> > 337 }
> >
> > This patch adds scope id to svc_addr_u for IPv6 address, and copy scope from
> > xprt->xpt_local to rqstp->rq_daddr for use.
> >
> > With this patch, lockd can callback to client success.
>
> I guess this makes sense to me, but someone who understands IPv6 better
> should comment... Chuck? Jeff?
>
Sounds like a reasonable explanation. Link-local addresses all have the
same prefix, so we need a scopeid (aka interface ID# for linux) to know
which interface we should send a call on.
When I did the patches to allow NFSv4 callbacks to go over IPv6, I
did something similar, but used the rq_addr. From gen_callback:
struct sockaddr *sa = svc_addr(rqstp);
u32 scopeid = rpc_get_scope_id(sa);
...and the scopeid was used to populate the scopeid of the callback
address. The rq_daddr should be equivalent though. The _addr and _daddr
must have the same scopeid or something is very wrong...
That said, on a semi-related note...
I have to wonder about statd in conjunction with link-local addresses.
I have a hard time understanding how you'd ever get reboot
notifications in such a setup.
You might be able to make it work if /etc/hosts allowed you to put in a
scopeid for an address, but even then it sounds sketchy...
--
Jeff Layton <jlayton@xxxxxxxxxx>
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