From: Nicolas Dichtel <nicolas.dichtel@6wind•com>
To: "Bjørn Mork" <bjorn@mork•no>
Cc: David Miller <davem@davemloft•net>,
netdev@vger•kernel.org, yoshfuji@linux-ipv6•org
Subject: Re: [PATCH net-next] ip6_tunnel: ensure to always have a link local address
Date: Wed, 21 Aug 2013 12:25:19 +0200 [thread overview]
Message-ID: <5214958F.1080907@6wind.com> (raw)
In-Reply-To: <87haej76wz.fsf@nemi.mork.no>
Le 21/08/2013 11:02, Bjørn Mork a écrit :
> Nicolas Dichtel <nicolas.dichtel@6wind•com> writes:
>> Le 21/08/2013 08:48, David Miller a écrit :
>>
>>> Applied, but this brings up an issue I keep noticing.
>>>
>>> We talk about eth_random_addr() and "uniqueness" together all the
>>> time, but the former never implies the latter.
>>>
>>> And we're going to run into situations where any conflicts generated
>>> by this random address generater will cause reall failures.
>>>
>>> Therefore we'll have to create a system to prevent them. Probably
>>> using some simple table that keeps track of the addresses we've
>>> generated.
>>>
>> Ok, I will look at this.
>
> Are eth_random_addr() collisions really any different than interfaces
> having the same address for other reasons?
I would tend to say yes, it's different.
It's easy for an administrator to fix a configuration for a physical interface,
because it's statically configured and there is a limited number of interfaces.
For virtual interfaces, they can be dynamically created and destroyed by daemons
and we can have a lot of interfaces. Hence it could be hard to fix them. Trying
to avoid these errors at kernel level could be useful.
I've start to write a patch, and to test it I've just run a simple test which
generate 1 000 000 of random addresses. I've run it several times (maybe not
enough ;-)) and I never get a duplicated address...
next prev parent reply other threads:[~2013-08-21 10:25 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-20 10:16 [PATCH net-next] ip6_tunnel: ensure to always have a link local address Nicolas Dichtel
2013-08-21 6:48 ` David Miller
2013-08-21 7:40 ` Nicolas Dichtel
2013-08-21 9:02 ` Bjørn Mork
2013-08-21 10:25 ` Nicolas Dichtel [this message]
2013-08-21 11:37 ` Bjørn Mork
2013-08-21 12:11 ` Nicolas Dichtel
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5214958F.1080907@6wind.com \
--to=nicolas.dichtel@6wind$(echo .)com \
--cc=bjorn@mork$(echo .)no \
--cc=davem@davemloft$(echo .)net \
--cc=netdev@vger$(echo .)kernel.org \
--cc=yoshfuji@linux-ipv6$(echo .)org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox