Subject: Re: [PATCH net-next 5/5] rocker: remove support for legacy VLAN ndo ops

From: Jamal Hadi Salim <[email-masked]>
Date: Tue, 02 Jun 2015 07:43:41 -0400

On 06/02/15 03:10, Scott Feldman wrote:

> Actually, we're now consistent with bridge man page which says master
> is the default.
>
> Want we want, I believe, is to adjust what the man page says (and the
> bridge vlan command itself), by making the default master and self.
> The kernel and driver are fine, it's the default in the bridge command
> that needs adjusting.  Once we do this, we'll be back to transparent
> with software-only bridge.
>

Question to ask when looking at something of this nature:
Will it work with no suprises if you used today's unmodified app?
The default behavior shouldnt change and unfortunately it does here.

It is not just iproute2 - since this is breaking ABI expectations.
Looking at some app i wrote a while back based on analyzing kernel
expectations at the time, I see the following logic:

user can set master or self on command line.
...
....
if (user DID NOT set master_on || user set self on)
    then set self to on

iow, current behavior:
  01: master is only set if user explicitly asked.
  11: master|self when user explicitly sets both
  10: self is on by default when the user doesnt specify anything
  00: and the last option is to have none set which is not
      possible since we have defaults.

cheers,
jamal

So this is very similar to iproute2 - if nothing is set
it defaults to self.

cheers,
jamal