From: Stephen Hemminger <shemminger@vyatta.com>
To: Jan Engelhardt <jengelh@medozas.de>
Cc: Stephen Hemminger <stephen.hemminger@vyatta.com>, netdev@vger.kernel.org
Subject: Re: iproute2: adding /128 address to sit interface borks
Date: Sat, 27 Feb 2010 08:23:56 -0800 [thread overview]
Message-ID: <20100227082356.67b7c0a3@nehalam> (raw)
In-Reply-To: <alpine.LSU.2.01.1002271601210.29398@obet.zrqbmnf.qr>
On Sat, 27 Feb 2010 16:03:36 +0100 (CET)
Jan Engelhardt <jengelh@medozas.de> wrote:
>
> On Friday 2009-07-10 17:27, Stephen Hemminger wrote:
> >On Fri, 10 Jul 2009 14:05:01 +0200 (CEST)
> >Jan Engelhardt <jengelh@medozas.de> wrote:
> >
> >> it's impossible to do this, and the error message does not say why
> >> that is so. No word in dmesg either.
> >>
> >> # ip a a fc00::49/128 peer fc00::7 dev sit7
> >> RTNETLINK answers: Invalid argument
> >
> >You will need to walk through the path in the kernel.
> >In worst case, it means adding kernel printk's.
> >
> >Then if you want to be nice, make a patch to ipaddr.c in iproute
> >utilities so command line can find the error before passing to
> >kernel and give a nice error :-)
>
> The issue here was that the peer is encoded using the broadcast
> field, and since IPv6 has no broadcast, it was rejected by
> the kernel. The error messages really need to be improved.
>
> This year also came an article about that,
> http://lwn.net/Articles/374794/
The article overlooks the fact that netlink is a message based interface.
There is no reason that the response message can't be extended to add
additional sections to give more detailed answer. The issues are:
* no infrastructure for this (message format, helpers, etc)
* tedious effort to annotate all the existing error returns
* update to command and library
The extended error reports could even be a kernel config option so the
embedded and those worried about space would not have to have it.
--
prev parent reply other threads:[~2010-02-27 16:24 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-07-10 12:05 iproute2: adding /128 address to sit interface borks Jan Engelhardt
2009-07-10 15:27 ` Stephen Hemminger
2010-02-27 15:03 ` Jan Engelhardt
2010-02-27 16:23 ` Stephen Hemminger [this message]
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