Tracking Issue for `ip_as_octets`

[npry]

Feature gate: #![feature(ip_as_octets)]

This is a tracking issue for enabling reference access to IpAddr, Ipv4Addr, and Ipv6Addr contents. Previously, only an array copy was exposed via .octets().

Public API

impl core::net::IpAddr {
    pub const fn as_octets(&self) -> &[u8];
}

impl core::net::Ipv4Addr {
    pub const fn as_octets(&self) -> &[u8; 4];
}

impl core::net::Ipv6Addr {
    pub const fn as_octets(&self) -> &[u8; 16];
}

Steps / History

• ACP: ref access to core::net::Ip*Addr octet bytes, impl AsRef<[u8]> for core::net::Ip*Addr libs-team#535
• Implementation: libcore/net: IpAddr::as_octets() #136609
• Final comment period (FCP)
• Stabilization PR

Unresolved Questions

• @tgross35 offered a potential alternative in the ACP: that we instead provide #[repr(transparent)] for these types and document layout stability, leaving transmutation to a byte slice to third-party libraries.

[bjoernager]

+1 for defining the representation. I'd also push for aligning Ipv4Addr (to 4 bytes) and Ipv6Addr (to 16 bytes) so that to-integer transmutations could be done in-place.

But are there currently any blockers to this? I don't see why we couldn't have both suggestions.

[tgross35]

I don't think there are any blockers. You may as well put up a PR for each if you're interested, to kick off discussion.