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From: Stephen Hemminger <stephen@networkplumber.org>
To: David Ahern <dsahern@gmail.com>
Cc: Jiri Benc <jbenc@redhat.com>,
	Christian Brauner <christian@brauner.io>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	David Miller <davem@davemloft.net>
Subject: Re: netlink: 16 bytes leftover after parsing attributes in process `ip'.
Date: Wed, 26 Sep 2018 16:02:42 +0100	[thread overview]
Message-ID: <20180926160242.6fe00491@shemminger-XPS-13-9360> (raw)
In-Reply-To: <7ffc4951-0d2e-5bf1-8d64-62ae5d6bc477@gmail.com>

On Wed, 26 Sep 2018 08:54:43 -0600
David Ahern <dsahern@gmail.com> wrote:

> On 9/25/18 11:51 PM, Jiri Benc wrote:
> > On Tue, 25 Sep 2018 09:37:41 -0600, David Ahern wrote:  
> >> For ifaddrmsg ifa_flags aligns with ifi_type which is set by kernel side
> >> so this should be ok.  
> > 
> > Does the existing user space set ifi_type to anything? Does it zero out
> > the field?
> > 
> > Are we able to find a flag value that is not going to be set by unaware
> > user space? I.e., a bit that is unused by the current ARPHRD values on
> > both little and big endian? (ARPHRD_NONE might be a problem, though...)  
> 
> The goal is for userpsace to pass something to the kernel to
> definitively state which header is used.
> 

You can not safely assume anything about older code.
iproute2 is not the only thing using the API, others include Quagga, and other tools.

Sorry, this API is frozen.

  reply	other threads:[~2018-09-26 21:16 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-25  3:19 netlink: 16 bytes leftover after parsing attributes in process `ip' David Ahern
2018-09-25  9:49 ` Christian Brauner
2018-09-25 12:07   ` Stephen Hemminger
     [not found]     ` <CAHrFyr55vt78akhC+WE5maDPLzmurUeB6wT-DmHcCmnAfPKrgw@mail.gmail.com>
2018-09-25 13:16       ` Stephen Hemminger
2018-09-26 10:45         ` Christian Brauner
2018-09-25 14:47   ` Jiri Benc
2018-09-25 15:37     ` David Ahern
2018-09-26  5:51       ` Jiri Benc
2018-09-26 14:54         ` David Ahern
2018-09-26 15:02           ` Stephen Hemminger [this message]
2018-09-26  9:49       ` Christian Brauner

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