uefi-raw: move types to net module

[phip1611]

Split-out from #1699.

We have enough network-related types to justify
a dedicated module:

• IpAddress
• Ipv4Address
• Ipv6Address
• MacAddress

Checklist

• Sensible git history (for example, squash "typo" or "fix" commits). See the Rewriting History guide for help.
• Update the changelog (if necessary)

[nicholasbishop]

There are a few unexpected changes:

diff --git a/uefi-raw/src/net.rs b/uefi-raw/src/net.rs
index 3b4f3e5f..71662aef 100644
--- a/uefi-raw/src/net.rs
+++ b/uefi-raw/src/net.rs
@@ -43,7 +43,7 @@ impl From<Ipv6Address> for core::net::Ipv6Addr {
 ///
 /// Corresponds to the `EFI_IP_ADDRESS` type in the UEFI specification. This
 /// type is defined in the same way as edk2 for compatibility with C code. Note
-/// that this is an **untagged union**, so there's no way to tell which type of
+/// that this is an untagged union, so there's no way to tell which type of
 /// address an `IpAddress` value contains without additional context.
 #[derive(Clone, Copy)]
 #[repr(C)]
@@ -106,15 +106,7 @@ impl From<core::net::IpAddr> for IpAddress {
     }
 }
 
-/// UEFI Media Access Control (MAC) address.
-///
-/// UEFI supports multiple network protocols and hardware types, not just
-/// Ethernet. Some of them may use MAC addresses longer than 6 bytes. To be
-/// protocol-agnostic and future-proof, the UEFI spec chooses a maximum size
-/// that can hold any supported media access control address.
-///
-/// In most cases, this is just a typical `[u8; 6]` Ethernet style MAC
-/// address with the rest of the bytes being zero.
+/// A Media Access Control (MAC) address.
 #[derive(Clone, Copy, Debug, Default, Eq, PartialEq, Ord, PartialOrd, Hash)]
 #[repr(transparent)]
 pub struct MacAddress(pub [u8; 32]);
@@ -122,7 +114,12 @@ pub struct MacAddress(pub [u8; 32]);
 impl From<[u8; 6]> for MacAddress {
     fn from(octets: [u8; 6]) -> Self {
         let mut buffer = [0; 32];
-        buffer.copy_from_slice(&octets);
+        buffer[0] = octets[0];
+        buffer[1] = octets[1];
+        buffer[2] = octets[2];
+        buffer[3] = octets[3];
+        buffer[4] = octets[4];
+        buffer[5] = octets[5];
         Self(buffer)
     }
 }

In particular, was dropping part of the MacAddress docstring intentional? The copy_from_slice change looks like a bugfix, since the slice lengths are different. Might be better to do that as buffer[..6].copy_from_slice(&octets);, but either way it ideally wouldn't be mixed into the same commit that splits out the module, or at least call it out in the commit message.

[phip1611]

Yikes. I was certain I fixed this already 🤔 I work from two different laptops - perhaps I fixed it on one without pushing and continued work on another - anyway, thanks for pointing that out! I'll fix it.

[phip1611]

Okay, I think it should be fixed now. Thanks for the close attention on this one, good catch