Re: [PATCH] rtnetlink: return the newly created link in response to newlink

From: Tom Gundersen
Date: Thu Jan 30 2014 - 19:57:53 EST


Hi Thomas,

Thanks for your reply.

On Thu, Jan 30, 2014 at 3:27 PM, Thomas Graf <tgraf@xxxxxxx> wrote:
> On 01/30/14 at 02:05pm, Tom Gundersen wrote:
>> Userspace needs to reliably know the ifindex of the netdevs it creates,
>> as we cannot rely on the ifname staying unchanged.
>>
>> Earlier, a simlpe NLMSG_ERROR would be returned, but this returns the
>> corresponding RTM_NEWLINK on success instead.
>
> This breaks existing Netlink applications in user space. User space
> apps are not prepared to receive both a RTM_NEWLINK reply _and_
> the ACK unless they have set NLM_F_ECHO in the original request.
>
> You can already reliably retrieve the ifindex by listening to
> RTNLGRP_LINK messages and be notified about the link created
> including all follow-up renames.

Ok, we'll keep doing this instead.

Cheers,

Tom
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