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

On Tuesday 17 August 2021 18:21:55 Pali Rohár wrote:

On Tuesday 17 August 2021 18:05:25 Guillaume Nault wrote:

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On Mon, Aug 16, 2021 at 06:23:55PM +0200, Pali Rohár wrote:

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On Monday 16 August 2021 18:11:14 Guillaume Nault wrote:

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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.

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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).

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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.