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Date:   Tue, 17 Aug 2021 18:05:25 +0200
From:   Guillaume Nault <gnault@redhat.com>
To:     Pali =?iso-8859-1?Q?Roh=E1r?= <pali@kernel.org>
Cc:     James Carlson <carlsonj@workingcode.com>,
        Chris Fowler <cfowler@outpostsentinel.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paul Mackerras <paulus@samba.org>,
        "David S. Miller" <davem@davemloft.net>,
        "linux-ppp@vger.kernel.org" <linux-ppp@vger.kernel.org>,
        "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] ppp: Add rtnl attribute IFLA_PPP_UNIT_ID for specifying
 ppp unit id
Message-ID: <20210817160525.GA20616@pc-32.home>
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On Mon, Aug 16, 2021 at 06:23:55PM +0200, Pali Roh?r 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?

> 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.