Le 31/05/2017 à 14:28, Flavio Leitner a écrit :

On Wed, May 31, 2017 at 10:38:21AM +0200, Nicolas Dichtel wrote:

quoted

Le 30/05/2017 à 23:33, Flavio Leitner a écrit :

quoted

Don't include netns id for notifications broadcasts when the
socket and the skb are in the same netns because it will be
an error which can't be distinguished from a peer netns failing
to allocate an id.

I don't understand the problem. peernet2id() doesn't allocate ids, it only do a
lookup. If you need an id for the current netns, you have to allocate one.

The issue is that if you query an interface on the same netns, the
error is returned, then we cannot tell if the iface is on the same
netns or if there was an error while allocating the ID and the
iface is on another netns.

If the returned id is NETNSA_NSID_NOT_ASSIGNED, then the netns is the same.

Some lines before your patch, we call peernet_has_id() when the netns differ,
thus we ensure that the id is available.

The principle was that netlink messages of other netns can be sent only if an id
is assigned.

quoted

This patch changes the metadata exported to the userland and will break existing
tools.

It should not break because it changes only for interfaces on
the same netns where there is no ID and that value wasn't
exported until recently.

It was exported since the initial patch (59324cf35aba ("netlink: allow to listen
"all" netns"). Am I wrong?


Regards,
Nicolas