Changes in memory layout of the std net types will result in UB

[ghost]

Context: rust-lang/rust#78802 and https://www.reddit.com/r/rust/comments/wcw93o/a_major_refactor_of_rusts_ip_address/

These lines caught my eye while I was reading the code:

netif/src/lib.rs

Lines 189 to 190 in 550ec42

	// Leans on the fact that SocketAddrV4 and SocketAddrV6 are
	// transparent wrappers around SOCKADDR.

netif/src/lib.rs

Lines 331 to 332 in 550ec42

	// Leans on the fact that SocketAddrV4 and SocketAddrV6 are
	// transparent wrappers around sockaddr_in and sockaddr_in6.

A lot of crates were recently patched to remove the assumption of the memory layout of network primitives. Any code continuing to do so will result in UB, so I wanted to raise this issue.

[bnoordhuis]

It should be fairly easy to fix. Do you want to send a PR or should I?

[ghost]

I never used libc/winapi or unsafe stuff, so I probably wouldn't know what to do. I'll leave it to you =)