Function is_non_global_v6 

pub fn is_non_global_v6(v6: Ipv6Addr) -> bool

True when an IPv6 address is not globally routable (loopback, ULA, link-local, site-local, documentation, multicast, unallocated/reserved, or an IPv4-embedded non-global v4).

IANA currently allocates global IPv6 unicast addresses from 2000::/3. This classifier additionally handles the globally reachable NAT64 well-known prefix and the more-specific exceptions in the IANA IPv6 Special-Purpose Address Registry. Everything else defaults closed.