Re: [PATCH net-next 3/3] net/sched: Introduce act_iptunnel

On Tue, Aug 23, 2016 at 05:33:49PM +0200, Jiri Benc wrote:

On Tue, 23 Aug 2016 18:28:05 +0300, Amir Vadai wrote:

quoted

On Mon, Aug 22, 2016 at 08:51:37PM +0200, Jiri Benc wrote:

quoted

2. We may run into problems like tx path seeing the metadata_dst that
   it should not see. This means either this situation or such
   configuration must be prevented somehow.

[...]

quoted

Anyway, this issue is orthogonal to this patchset...

Not really. If it's indeed (2) then such configuration needs to be
rejected. 

The configuration that needs to be rejected is when act_iptunnel is not
used. So, I guess the fix won't be part of it...

Or metadata_dst freed at an appropriate place. Thus it's
something that needs to be handled by this patchset before the uAPI is
set in stone.

It is already there - user can use act_mirred and redirect skb's with
metadata since shared tunnel devices introduced.
The only thing that was added here, is to enable the user to drop the
metadata, which I think we agree is the ok.

But I agree with you, that I must understand the life cycle of the metadata and dst
better. I will try to understand it better and explain/fix accordingly.

Again, would be happy if someone will chime in and give some hints if it
was a bug, that a user could redirect skb's with metadata, or something
harmless.

Thanks,
Amir

 Jiri