feat(network): add Ipv4Addr::LOOPBACK

Signed-off-by: Anhad Singh <[email protected]>

src/network.rs

@@ -12,7 +12,12 @@ impl Ipv4Addr {
     ///
     /// [RFC 8200 § 2]: https://www.rfc-editor.org/rfc/rfc791#section-3.2
     pub const ADDR_SIZE: usize = 4;
+    /// Broadcast address.
     pub const BROADCAST: Self = Self([0xff; Self::ADDR_SIZE]);
+    /// Loopback address.
+    pub const LOOPBACK: Self = Self([127, 0, 0, 1]);
+    // FIXME(andypython): [`Ipv4Addr::NULL`] should not really be used anywhere except for testing.
+    // Consider removing it to avoid misuse/confusion.
     pub const NULL: Self = Self([0; Self::ADDR_SIZE]);
 
     pub fn new(addr: [u8; Self::ADDR_SIZE]) -> Self {