[Nut-upsdev] Re: [nut-commits] svn commit r714 - in trunk: . server

[Henning Brauer]

* Arjen de Korte <arjen at de-korte.org> [2007-01-08 15:45]:
> > but keep in mind that there are systems that (purposefully) do not
> > support v4 mapped addresses.
> That shouldn't be too much of a problem, would it?

This is only a problem if you open exactly one listening socket with 
AF_INET6 and expect to handle both v4 and v6 connections there, seeing 
v4 traffic mapped.

> I may not fully
> understand the problem here, but if you only use either IPv4 or IPv6
> addresses, the code for IPv4 mapped addresses will not be used anyway.

see above - as long as you don't expect to see AF_INET traffic on 
AF_INET6 sockets, all is good.

> Or
> do you mean that we should check for the case that IPv4 access controls
> are specified on an IPv6 only system that is not supporting IPv4 mapping?

the access controls problem is one of the fundamental issues with the 
v4 mapped adresses indeed :)
but that is not really nut's problem.
you might want to either drop v4-mapped traffic on AF_INET6 sockets 
entirely (and use AF_INET sockets exlucisvely for v4 traffic, that is 
what I'd recommend), or at least check v4 access controls on AF_INET6 
traffic for v4-mapped addresses.

> Looking at the code, the latter would probably mean that no connections
> are allowed at all, so no harm is done.

as said, I'd play safe and silently drop all v4mapped stuff on the 
AF_INET6 socket.

-- 
Henning Brauer, hb at bsws.de, henning at openbsd.org
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