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From: Stephen Hemminger <stephen@networkplumber•org>
To: David Ahern <dsahern@gmail•com>
Cc: David Miller <davem@davemloft•net>,
	andrew@lunn•ch, vkuznets@redhat•com, eric.dumazet@gmail•com,
	netdev@vger•kernel.org, edumazet@google•com
Subject: Re: [PATCH RFC net-next] net: Allow name change of IFF_UP interfaces
Date: Thu, 10 Aug 2017 10:16:19 -0700	[thread overview]
Message-ID: <20170810101619.15142772@xeon-e3> (raw)
In-Reply-To: <88b507b7-1b60-5100-3e31-b68263f0f631@gmail.com>

On Thu, 10 Aug 2017 10:55:01 -0600
David Ahern <dsahern@gmail•com> wrote:

> On 8/10/17 10:48 AM, David Miller wrote:
> > From: Andrew Lunn <andrew@lunn•ch>
> > Date: Thu, 10 Aug 2017 18:27:22 +0200
> >   
> >> On Thu, Aug 10, 2017 at 05:24:55PM +0200, Vitaly Kuznetsov wrote:  
> >>> Andrew Lunn <andrew@lunn•ch> writes:
> >>>  
> >>>>> We are - rtnetlink_event() does the job. We, however, don't have a
> >>>>> special IFLA_EVENT_* for name change and end up with IFLA_EVENT_NONE.  
> >>>>
> >>>> What is in this event? Old and new name? Just the new name?  
> >>>
> >>> Basically, it's everything we know about the interface - type, index,
> >>> name, mtu, qdisc, ... - see rtnl_fill_ifinfo(). Back to your question -
> >>> it's only the new name.  
> >>
> >> So the program needs to keep track of ifindex to know which interface
> >> has changed name. Doable.
> >>
> >> I still expect this has the potential to break something. You probably
> >> should be asking on linux-api for the API experts opinion.  
> > 
> > But a greater point is that nobody is monitoring device renames
> > explicitly right now.  
> 
> Just to throw in an example:
>   https://github.com/kobolabs/dhcpcd/blob/kobo/if-linux.c#L761
> 
> Learned of its use from a recent regression:
> https://bugzilla.kernel.org/show_bug.cgi?id=196355

Quagga is another example of what might break. Especially with all the new
forks..

  reply	other threads:[~2017-08-10 17:16 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-09 10:42 [PATCH RFC net-next] net: Allow name change of IFF_UP interfaces Vitaly Kuznetsov
2017-08-09 12:29 ` 吉藤英明
2017-08-09 15:05   ` Vitaly Kuznetsov
2017-08-09 16:10     ` Andrew Lunn
2017-08-10  8:41       ` Vitaly Kuznetsov
2017-08-10  9:03         ` Eric Dumazet
2017-08-10 10:01           ` Vitaly Kuznetsov
2017-08-10 14:13             ` Andrew Lunn
2017-08-10 15:24               ` Vitaly Kuznetsov
2017-08-10 16:27                 ` Andrew Lunn
2017-08-10 16:33                   ` Vitaly Kuznetsov
2017-08-10 16:48                   ` David Miller
2017-08-10 16:55                     ` David Ahern
2017-08-10 17:16                       ` Stephen Hemminger [this message]
2017-08-11  9:01                         ` Vitaly Kuznetsov
2017-08-10 14:10         ` Andrew Lunn

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