[PATCH] bird: treat former classe addresses as valid addresses

[Ondrej Zajicek]

On Tue, Dec 11, 2018 at 03:26:08PM -0800, Dave Taht wrote:
> There is no reason to disallow the former class e address
> space, except in a bogon file.

Hi

>  static inline int ip4_is_unicast(ip4_addr a)
> -{ return _I(a) < 0xe0000000; }
> +{ return _I(a) < 0xe0000000 || (_I(a) >= 0xf0000000 && _I(a) != 0xffffffff); }

Well, this summarises the reason why to disallow former class E address
space. If these addresses are not defined / reserved for future use, how
can we say that they are unicast and not multicast or for some complete
different but not yet defined purpose?

IMHO first should IETF redefine it as a regular unicast range, then
routing software should change its behavior. Please correct me if
that already happened.

OTOH, perhaps we could allow all possible routes regardless of address
classification (even for prefixes from multicast range) in routing table.
OSes allow that and sometimes even uses that (e.g. route for multicast
range in regular unicast table is used for selection of default multcast
interface on clients).

-- 
Elen sila lumenn' omentielvo

Ondrej 'Santiago' Zajicek (email: santiago at crfreenet.org)
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"To err is human -- to blame it on a computer is even more so."