Re: [v6ops] The need for local-ipv4 socket transition solutions -- NAT64/DNS64 remains insufficient

[Lorenzo Colitti <[e-mail]>]

On Thu, Apr 23, 2015 at 7:36 AM, James Woodyatt <[e-mail]> wrote:

> In particular, I think it's critical to have a clear understanding of
> precisely what features of the PF_INET interfaces are expected to be
> handled by the CLAT function. If the IP_PKTINFO socket option, for example,
> is expected to be unsupported, then it's important to know that. What
> does the CLAT do with IPv4 link-local scope addresses? What about the
> SO_REUSEADDR option? A good place to start would probably be to go through
> the entire POSIX.1 standard, and for all the IPv4 networking interfaces,
> describe what is and isn't supported by the CLAT function recommended by
> IETF.
>

I don't think such a fine-toothed-comb endeavour makes sense. 464xlat is
just an unnumbered point-to-point link. That directly implies that the
answers to your questions are "there's no reason not to support IP_PKTINFO,
and no extra work required to do so", "link-local scope addresses are not
supported because it's an unnumbered point-to-point link", and
"SO_REUSEADDR means exactly what it means on any other IP address on the
system".

I suppose we can always write a document saying the above, plus
recommending that there be a different local clat IP address for every
interface on the system. Such a document wouldn't be very long, but I
suppose it might be helpful.

I don't think there is a need to go through POSIX.1. looking for corner
cases.