[prev in list] [next in list] [prev in thread] [next in thread] 

List:       netbsd-tech-net
Subject:    Re: IPv6 socket behaviour different to IPv4?
From:       Darren Reed <darrenr () netbsd ! org>
Date:       2014-06-05 10:38:07
Message-ID: 5390488F.1000603 () netbsd ! org
[Download RAW message or body]

On 5/06/2014 7:39 AM, 神明達哉 wrote:
>>>   Disabling DAD on that interface certainly looks too
>>> much if the purpose is to allow node-local communication using a
>>> "detached" address.  One possibility would be to introduce a tweakable
>>> switch that disables the DNA operation at the risk of allowing the
>>> small window on link up.  Another, probably more substantial but
>>> probably cleaner change would be to allow using a detached address for
>>> (node) local communication (e.g., allow bind() but filter out packets
>>> using a detached address if they are sent to the wire rather than
>>> loopback).

All of these suggestions have merit as I'm also of a mind to not
disable (or need to disable) DAD just to support node-local
communication whilst the link is down.

>> I've not tested this, but wouldn't a host route to the interface address
>> via the loopback address work?
> Is this a question of whether local communication using a detached
> address is currently possible?  I don't fully remember either, but the
> host route itself should work (unless it's removed as a result of the
> status change to detached).  But there may be other issues, like
> whether bind(2) is allowed for that address.

Yes - part of the problem here is that bind(2) currently fails and I cannot
see how creating a host route would fix that.

Darren
[prev in list] [next in list] [prev in thread] [next in thread]