Rollup merge of rust-lang#86439 - CDirkx:ip-protocol-assignment, r=m-ou-se

Remove `Ipv4Addr::is_ietf_protocol_assignment`

This PR removes the unstable method `Ipv4Addr::is_ietf_protocol_assignment`, as I suggested in rust-lang#85612 (comment). The method was added in rust-lang#60145, as far as I can tell primarily for the implementation of `Ipv4Addr::is_global` (addresses reserved for IETF protocol assignment are not globally reachable unless otherwise specified).

The method was added in 2019, but I haven't been able to find any open-source code using this method so far. I'm also having a hard time coming up with a usecase for specifically this method; knowing that an address is reserved for future protocols doesn't allow you to do much with it, especially since now some of those addresses are indeed assigned to a protocol and have their own behaviour (and might even be defined to be globally reachable, so if that is what you care about it is always more accurate to call `!is_global()`, instead of `is_ietf_protocol_assignment()`).

Because of these reasons, I propose removing the method (or alternatively make it a private helper for `is_global`) and also not introduce `Ipv6Addr::is_ietf_protocol_assignment` and `IpAddr::is_ietf_protocol_assignment` in the future.

Author: JohnTitor

library/std/src/net/ip.rs

@@ -486,8 +486,7 @@ impl Ipv4Addr {
     /// - addresses used for documentation (see [`Ipv4Addr::is_documentation()`])
     /// - the unspecified address (see [`Ipv4Addr::is_unspecified()`]), and the whole
     ///   `0.0.0.0/8` block
-    /// - addresses reserved for future protocols (see
-    /// [`Ipv4Addr::is_ietf_protocol_assignment()`], except
+    /// - addresses reserved for future protocols, except
     /// `192.0.0.9/32` and `192.0.0.10/32` which are globally routable
     /// - addresses reserved for future use (see [`Ipv4Addr::is_reserved()`]
     /// - addresses reserved for networking devices benchmarking (see
@@ -560,7 +559,8 @@ impl Ipv4Addr {
             && !self.is_broadcast()
             && !self.is_documentation()
             && !self.is_shared()
-            && !self.is_ietf_protocol_assignment()
+            // addresses reserved for future protocols (`192.0.0.0/24`)
+            && !(self.octets()[0] == 192 && self.octets()[1] == 0 && self.octets()[2] == 0)
             && !self.is_reserved()
             && !self.is_benchmarking()
             // Make sure the address is not in 0.0.0.0/8
@@ -589,40 +589,6 @@ impl Ipv4Addr {
         self.octets()[0] == 100 && (self.octets()[1] & 0b1100_0000 == 0b0100_0000)
     }
 
-    /// Returns [`true`] if this address is part of `192.0.0.0/24`, which is reserved to
-    /// IANA for IETF protocol assignments, as documented in [IETF RFC 6890].
-    ///
-    /// Note that parts of this block are in use:
-    ///
-    /// - `192.0.0.8/32` is the "IPv4 dummy address" (see [IETF RFC 7600])
-    /// - `192.0.0.9/32` is the "Port Control Protocol Anycast" (see [IETF RFC 7723])
-    /// - `192.0.0.10/32` is used for NAT traversal (see [IETF RFC 8155])
-    ///
-    /// [IETF RFC 6890]: https://tools.ietf.org/html/rfc6890
-    /// [IETF RFC 7600]: https://tools.ietf.org/html/rfc7600
-    /// [IETF RFC 7723]: https://tools.ietf.org/html/rfc7723
-    /// [IETF RFC 8155]: https://tools.ietf.org/html/rfc8155
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// #![feature(ip)]
-    /// use std::net::Ipv4Addr;
-    ///
-    /// assert_eq!(Ipv4Addr::new(192, 0, 0, 0).is_ietf_protocol_assignment(), true);
-    /// assert_eq!(Ipv4Addr::new(192, 0, 0, 8).is_ietf_protocol_assignment(), true);
-    /// assert_eq!(Ipv4Addr::new(192, 0, 0, 9).is_ietf_protocol_assignment(), true);
-    /// assert_eq!(Ipv4Addr::new(192, 0, 0, 255).is_ietf_protocol_assignment(), true);
-    /// assert_eq!(Ipv4Addr::new(192, 0, 1, 0).is_ietf_protocol_assignment(), false);
-    /// assert_eq!(Ipv4Addr::new(191, 255, 255, 255).is_ietf_protocol_assignment(), false);
-    /// ```
-    #[rustc_const_unstable(feature = "const_ipv4", issue = "76205")]
-    #[unstable(feature = "ip", issue = "27709")]
-    #[inline]
-    pub const fn is_ietf_protocol_assignment(&self) -> bool {
-        self.octets()[0] == 192 && self.octets()[1] == 0 && self.octets()[2] == 0
-    }
-
     /// Returns [`true`] if this address part of the `198.18.0.0/15` range, which is reserved for
     /// network devices benchmarking. This range is defined in [IETF RFC 2544] as `192.18.0.0`
     /// through `198.19.255.255` but [errata 423] corrects it to `198.18.0.0/15`.

library/std/src/net/ip/tests.rs

@@ -339,7 +339,6 @@ fn ipv4_properties() {
             let broadcast: u16 = 1 << 6;
             let documentation: u16 = 1 << 7;
             let benchmarking: u16 = 1 << 8;
-            let ietf_protocol_assignment: u16 = 1 << 9;
             let reserved: u16 = 1 << 10;
             let shared: u16 = 1 << 11;
 
@@ -397,12 +396,6 @@ fn ipv4_properties() {
                 assert!(!ip!($s).is_benchmarking());
             }
 
-            if ($mask & ietf_protocol_assignment) == ietf_protocol_assignment {
-                assert!(ip!($s).is_ietf_protocol_assignment());
-            } else {
-                assert!(!ip!($s).is_ietf_protocol_assignment());
-            }
-
             if ($mask & reserved) == reserved {
                 assert!(ip!($s).is_reserved());
             } else {
@@ -426,7 +419,6 @@ fn ipv4_properties() {
     let broadcast: u16 = 1 << 6;
     let documentation: u16 = 1 << 7;
     let benchmarking: u16 = 1 << 8;
-    let ietf_protocol_assignment: u16 = 1 << 9;
     let reserved: u16 = 1 << 10;
     let shared: u16 = 1 << 11;
 
@@ -449,9 +441,9 @@ fn ipv4_properties() {
     check!("198.18.0.0", benchmarking);
     check!("198.18.54.2", benchmarking);
     check!("198.19.255.255", benchmarking);
-    check!("192.0.0.0", ietf_protocol_assignment);
-    check!("192.0.0.255", ietf_protocol_assignment);
-    check!("192.0.0.100", ietf_protocol_assignment);
+    check!("192.0.0.0");
+    check!("192.0.0.255");
+    check!("192.0.0.100");
     check!("240.0.0.0", reserved);
     check!("251.54.1.76", reserved);
     check!("254.255.255.255", reserved);
@@ -823,9 +815,6 @@ fn ipv4_const() {
     const IS_SHARED: bool = IP_ADDRESS.is_shared();
     assert!(!IS_SHARED);
 
-    const IS_IETF_PROTOCOL_ASSIGNMENT: bool = IP_ADDRESS.is_ietf_protocol_assignment();
-    assert!(!IS_IETF_PROTOCOL_ASSIGNMENT);
-
     const IS_BENCHMARKING: bool = IP_ADDRESS.is_benchmarking();
     assert!(!IS_BENCHMARKING);