Re: [PATCH] ppp: Add rtnl attribute IFLA_PPP_UNIT_ID for specifying ppp unit id

[Guillaume Nault]

On Sat, Jul 09, 2022 at 02:09:06PM +0200, Pali Rohár wrote:
> On Tuesday 17 August 2021 18:21:55 Pali Rohár wrote:
> > On Tuesday 17 August 2021 18:05:25 Guillaume Nault wrote:
> > > On Mon, Aug 16, 2021 at 06:23:55PM +0200, Pali Rohár wrote:
> > > > On Monday 16 August 2021 18:11:14 Guillaume Nault wrote:
> > > > > Do you have plans for adding netlink support to pppd? If so, is the
> > > > > project ready to accept such code?
> > > > 
> > > > Yes, I have already some WIP code and I'm planning to send a pull
> > > > request to pppd on github for it. I guess that it could be accepted,
> > > 
> > > I guess you can easily use the netlink api for cases where the "unit"
> > > option isn't specified and fall back to the ioctl api when it is. If
> > > all goes well, then we can extend the netlink api to accept a unit id.
> > > 
> > > But what about the lack of netlink feedback about the created
> > > interface? Are you restricted to use netlink only when the "ifname"
> > > option is provided?
> > 
> > Exactly, this is how I wrote my WIP code...
> 
> Sorry for a long delay (I forgot about it). Now I created pull request
> for pppd https://github.com/ppp-project/ppp/pull/354 which adds support
> for creating ppp interface via rtnetlink. rtnetlink is used only when
> ppp unit id was not provided and interface name was provided.

Interesting work. Thanks for working on it!

> > > > specially if there still would be backward compatibility via ioctl for
> > > > kernels which do not support rtnl API.
> > > 
> > > Indeed, I'd expect keeping compatiblitity with old kernels that only
> > > have the ioctl api to be a must (but I have no experience contributing
> > > to the pppd project).
> > > 
> > > > One of the argument which can be
> > > > used why rtnl API is better, is fixing issue: atomic creating of
> > > > interface with specific name.
> > > 
> > > Yes, that looks useful.
> > > 
>