Missing a private address range | 100.64.0.0/10

[gregorst3]

Hello, there is a private address range missing from the Ipv4Addr filter:

As per here https://doc.rust-lang.org/beta/src/std/net/ip.rs.html#557-564

 /// The private address ranges are defined in [IETF RFC 1918] and include:
    ///
    ///  - `10.0.0.0/8`
    ///  - `172.16.0.0/12`
    ///  - `192.168.0.0/16`

There is also another private range defined in rfc6598 , the 100.64.0.0/10 range https://datatracker.ietf.org/doc/html/rfc6598 , today some providers are banning the use of it because it's used to deploy carrier-grade NAT (CGN) services.

I run my applications by filtering the use of Ipv4Addr ranges (substrate p2p nodes)... however, because the applications reads Ipv4Addr to filter the ip that doesn't need to be scanned, I receive abuse due to the 100.64.0.0 missing from the filter.

time protocol src_ip src_port dest_ip dest_port
Sun Oct 3 07:59:57 2021 TCP My_IP 42188 => 100.98.83.192 30336
Sun Oct 3 08:00:00 2021 TCP My_IP 42188 => 100.98.83.192 30336
Sun Oct 3 07:59:17 2021 TCP My_IP 46722 => 100.103.178.192 30336
Sun Oct 3 07:59:18 2021 TCP My_IP 46722 => 100.103.178.192 30336
Sun Oct 3 07:59:20 2021 TCP My_IP 46722 => 100.103.178.192 30336
Sun Oct 3 08:08:29 2021 TCP My_IP 52080 => 100.103.178.192 30336
Sun Oct 3 08:08:30 2021 TCP My_IP 52080 => 100.103.178.192 30336

[hkratz]

Quoting RFC 6598: "Shared Address Space is distinct from RFC 1918 private address space because it is intended for use on Service Provider networks." So is_private() should not return true for those addresses.

There already is Ipv4Addr::is_shared() which returns trueif the IP address is in 100.64.0.0/10. Unfortunately this is currently nightly-only.

CC tracking issues: #27709, #85612

[joshtriplett]

Closing based on the response from @hkratz.