From mboxrd@z Thu Jan  1 00:00:00 1970
From: Stephen Hemminger <stephen@networkplumber.org>
Subject: Re: [PATCH v2 10/10] kni: add API to set link status on
 kernel interface
Date: Wed, 29 Aug 2018 15:00:14 -0700
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Cc: Ferruh Yigit <ferruh.yigit@intel.com>, dev@dpdk.org
To: Dan Gora <dg@adax.com>
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On Wed, 29 Aug 2018 18:02:06 -0300
Dan Gora <dg@adax.com> wrote:

> On Wed, Aug 29, 2018 at 12:54 PM, Stephen Hemminger
> <stephen@networkplumber.org> wrote:
> > On Thu, 28 Jun 2018 18:55:08 -0700
> > Dan Gora <dg@adax.com> wrote:
> >  
> >> Add a new API function to KNI, rte_kni_update_link() to allow DPDK
> >> applications to update the link state for the KNI network interfaces
> >> in the linux kernel.
> >>
> >> Note that the default carrier state is set to off when the interface
> >> is opened.
> >>
> >> Signed-off-by: Dan Gora <dg@adax.com>  
> >
> > Do you really need a special ioctl for this?
> > There is already ability to set link state via sysfs or netlink.  
> 
> I think yes.. AFAIK sysfs does not constitute a stable API; 

It is a stable API on Linux.

> it's only
> available for Linux (yes, I know KNI is linux-only currently, but
> there's not really any technical reason why it can't work on BSD) and
> there are already callbacks to change the MTU and MAC addresses which
> could also be done via netlink.  IMHO having the kernel have an
> accurate view of the link state is more important than the ability to
> change the MAC address of the interface...

The device model on BSD is significantly different than Linux.
Doing KNI on BSD is going to be a full rewrite of the driver anyway;
I won't worry about sysfs, dependency.

The important part is that if KNI is ever going to be supportable
it needs to be upstream in Linux, not a bolt on out of tree driver.
Most Enterprise distributions will not support out of tree drivers
for good reasons.