Re: [v6ops] prefix length ban for RFC4861 (Re: A proposal for draft-ietf-6man-rfc4291bis-07)

The USGv6 and IPv6 Ready Logo have the same test for the PIO option with a
prefix length larger then 64.

It's test 2.2.19 in the IPv6 Core Test Specification
<https://www.ipv6ready.org/docs/Core_Conformance_Latest.pdf>.

It checks that a device is capable of determining the on-link prefix with a
length set to 96.   All IPv6 Ready Logo/USGv6 Basic devices support this
properly.

~Tim

On Mon, Mar 6, 2017 at 5:26 PM, james woodyatt <jhw@google.com> wrote:

> On Mar 6, 2017, at 14:15, 神明達哉 <jinmei@wide.ad.jp> wrote:
>
>
> BSD variants did NOT ignore PIO for on-link determination simply due
> to its prefix length value at least at the time of the publication of
> RFC4862 (actually since way before that RFC).  For example, this is
> FreeBSD's implementation as of Oct 21, 2005, about two years before
> RFC4862 was published:
> https://github.com/freebsd/freebsd/blob/c2b19f24a4ba01108e047a35a4a060
> cbfdf28a17/sys/netinet6/nd6_rtr.c
> see nd6_prelist_add() starting at line 993, and find that it only
> checks the prefix length for SLAAC (lines from 1258).  At this point
> the on-link determination has been completed without any check on the
> prefix length (lines 1043-1056).
>
>
> Indeed, I am unable to find source code history in FreeBSD, NetBSD or
> Darwin consistent with my memory. Perhaps I am mistaken that it was ever
> there.
>
> order to pass a certification test. I believe these implementations
> will not any longer pass that test. (One imagines either their
> owners don’t care, or the test has been revised to be more lenient.)
>
>
> This is quite surprising to me.  Do you have any reference to such a
> certification test that requires the host to ignore PIO with a non-64
> prefix length for the purpose of on-link determination (i.e., for
> RFC4861)?
>
>
> My admittedly questionable memory is that it was a USGv6 Test Program for
> SLAAC [Host] Conformance that checked for this behavior in a host
> implementation I maintained at the time. As I said, I wouldn’t be surprised
> if that test has been revised to be more lenient, but I remember having to
> modify the KAME source code to pass the test.
>
> Nevertheless, the LwIP stack does what I’m talking about, and it’s used in
> a plethora of constrained resource host operating systems these days.
>
>
> --james woodyatt <jhw@google.com>
>
>
>
>
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