Text for IPv6 Scope

[JINMEI Tatuya / 神明達哉]

At Sat, 5 Jan 2008 12:52:53 +0100,
Michael Tuexen <Michael.Tuexen at lurchi.franken.de> wrote:

> aren't site-local IPv6 addresses depreceated (RFC 3879)? So shouldn't
> the site-local stuff be removed?

RFC3879 only deprecates site-local *unicast* addresses; the notion of
"site-local" is still valid for multicast addresses (this is a very
common misunderstanding about the "deprecation of site-local").  So we
should not remove IPV6_ADDR_SCOPE_SITELOCAL from in6.h.

Going back to the original question of this thread, I don't have a
strong opinion on whether it's a good idea to show scope types in
alphabets.  But I'd point out that it might break convention (further)
that an output of ifconfig can often be used as an input, too.  For
example, if we have:

ed0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        inet6 fe80::2c4:77ff:fea1:55ed%ed0 prefixlen 64 scopeid 0x1 
        inet 10.211.55.11 netmask 0xffffff00 broadcast 10.211.55.255
        inet6 2001:db8::1234 prefixlen 64 
        ether 00:c4:77:a1:55:ed
        media: Ethernet autoselect (10baseT/UTP)

then we could do
# ifconfig ed0 `ifconfig ed0 | grep 'inet6 2001'`

Adding the scope type text would break this convention (at least if
implemented naively).  I don't know whether people care about this
much, though.  Also, we've actually already broken this convention by
showing 'scoped 0xXX' for link-locals, so it may not be a big deal any
more.

BTW, the patch in its current form is not correct in that "scopeid" is
the scope index of a specific type of scope, not the "scope type"
(link-local, site-local, etc).

---
JINMEI, Tatuya
Internet Systems Consortium, Inc.