Subject: Re: [PATCH net-next v5] rtnetlink: add new RTM_GETSTATS message to dump link stats

From: Johannes Berg <[email-masked]>
Date: Wed, 20 Apr 2016 22:13:50 +0200

On Wed, 2016-04-20 at 15:34 +0200, Jiri Benc wrote:
> On Wed, 20 Apr 2016 15:17:08 +0200, Johannes Berg wrote:
> > 
> > Looks like you have this on a per-message basis. I thought it was
> > better on an attribute basis because that's really where the issue
> > is.
> No problem. I'm not that happy with my patchset myself. Just wanted
> to point it out in case it's useful.

Yeah, I looked at it, but I think it ended up a bit too complicated
really.

It does have slightly more validation in some sense, but I don't really
think that justifies the complexity?

No matter what, we'll always have to deal with the problem of not
having this capability on older kernels. One way to work around it
would be to add a new NLM_F_REQUEST2 flag, since the kernel currently
requires having NLM_F_REQUEST set, NLM_F_REQUEST2 messages would be
rejected by existing kernels. Dunno if it's really worth it though, I
suspect that family/command-specific detection will work in practically
all cases.

johannes