Combined changes to allow experimentation with net 0/8 (network 0),
240/4 (Experimental/"Class E"), and part of the loopback net 127/8
(all but 127.0/16). All changes are disabled by default, and can be
enabled by the following sysctls:
net.inet.ip.allow_zeronet=1 net.inet.ip.allow_experimental=1 net.inet.ip.loopback_mask=0xffff0000
When enabled, the corresponding addresses can be used as normal
unicast IP addresses, both as endpoints and when forwarding.
The proposals motivating this experimentation can be found in
https://datatracker.ietf.org/doc/draft-schoen-intarea-unicast-0/01/ https://datatracker.ietf.org/doc/draft-schoen-intarea-unicast-240/ https://datatracker.ietf.org/doc/draft-schoen-intarea-unicast-127/
This review is not expected to be pushed as is; it is for comment
only at this time. The loopback_mask will probably be replaced
by a prefix length.