Rollup merge of #76142 - CDirkx:const-ip, r=ecstatic-morse

Make all methods of `std::net::Ipv4Addr` const

Make the following methods of `std::net::Ipv4Addr` unstable const under the `const_ipv4` feature:
 - `octets`
 - `is_loopback`
 - `is_private`
 - `is_link_local`
 - `is_global` (unstable)
 - `is_shared` (unstable)
 - `is_ietf_protocol_assignment` (unstable)
 - `is_benchmarking` (unstable)
 - `is_reserved` (unstable)
 - `is_multicast`
 - `is_broadcast`
 - `is_documentation`
 - `to_ipv6_compatible`
 - `to_ipv6_mapped`

This would make all methods of `Ipv6Addr` const.

Of these methods, `is_global`, `is_broadcast`, `to_ipv6_compatible`, and `to_ipv6_mapped` require a change in implementation.

Part of #76205

3 files changed, 97 insertions, 18 deletions

diff --git a/library/std/src/lib.rs b/library/std/src/lib.rs
index 3141b3b9526..dc57c1c1f44 100644
--- a/library/std/src/lib.rs
+++ b/library/std/src/lib.rs
@@ -240,6 +240,7 @@
 #![feature(const_fn_transmute)]
 #![feature(const_ipv6)]
 #![feature(const_raw_ptr_deref)]
+#![feature(const_ipv4)]
 #![feature(container_error_extra)]
 #![feature(core_intrinsics)]
 #![feature(custom_test_frameworks)]
diff --git a/library/std/src/net/ip.rs b/library/std/src/net/ip.rs
index 5aff2b5bb78..3f9afae880f 100644
--- a/library/std/src/net/ip.rs
+++ b/library/std/src/net/ip.rs
@@ -365,8 +365,9 @@ impl Ipv4Addr {
     /// let addr = Ipv4Addr::new(127, 0, 0, 1);
     /// assert_eq!(addr.octets(), [127, 0, 0, 1]);
     /// ```
+    #[rustc_const_unstable(feature = "const_ipv4", issue = "76205")]
     #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn octets(&self) -> [u8; 4] {
+    pub const fn octets(&self) -> [u8; 4] {
         // This returns the order we want because s_addr is stored in big-endian.
         self.inner.s_addr.to_ne_bytes()
     }
@@ -408,8 +409,9 @@ impl Ipv4Addr {
     /// assert_eq!(Ipv4Addr::new(127, 0, 0, 1).is_loopback(), true);
     /// assert_eq!(Ipv4Addr::new(45, 22, 13, 197).is_loopback(), false);
     /// ```
+    #[rustc_const_unstable(feature = "const_ipv4", issue = "76205")]
     #[stable(since = "1.7.0", feature = "ip_17")]
-    pub fn is_loopback(&self) -> bool {
+    pub const fn is_loopback(&self) -> bool {
         self.octets()[0] == 127
     }
 
@@ -437,8 +439,9 @@ impl Ipv4Addr {
     /// assert_eq!(Ipv4Addr::new(192, 168, 0, 2).is_private(), true);
     /// assert_eq!(Ipv4Addr::new(192, 169, 0, 2).is_private(), false);
     /// ```
+    #[rustc_const_unstable(feature = "const_ipv4", issue = "76205")]
     #[stable(since = "1.7.0", feature = "ip_17")]
-    pub fn is_private(&self) -> bool {
+    pub const fn is_private(&self) -> bool {
         match self.octets() {
             [10, ..] => true,
             [172, b, ..] if b >= 16 && b <= 31 => true,
@@ -463,8 +466,9 @@ impl Ipv4Addr {
     /// assert_eq!(Ipv4Addr::new(169, 254, 10, 65).is_link_local(), true);
     /// assert_eq!(Ipv4Addr::new(16, 89, 10, 65).is_link_local(), false);
     /// ```
+    #[rustc_const_unstable(feature = "const_ipv4", issue = "76205")]
     #[stable(since = "1.7.0", feature = "ip_17")]
-    pub fn is_link_local(&self) -> bool {
+    pub const fn is_link_local(&self) -> bool {
         match self.octets() {
             [169, 254, ..] => true,
             _ => false,
@@ -542,10 +546,13 @@ impl Ipv4Addr {
     /// assert_eq!(Ipv4Addr::new(1, 1, 1, 1).is_global(), true);
     /// assert_eq!(Ipv4Addr::new(80, 9, 12, 3).is_global(), true);
     /// ```
-    pub fn is_global(&self) -> bool {
+    #[rustc_const_unstable(feature = "const_ipv4", issue = "76205")]
+    pub const fn is_global(&self) -> bool {
         // check if this address is 192.0.0.9 or 192.0.0.10. These addresses are the only two
         // globally routable addresses in the 192.0.0.0/24 range.
-        if u32::from(*self) == 0xc0000009 || u32::from(*self) == 0xc000000a {
+        if u32::from_be_bytes(self.octets()) == 0xc0000009
+            || u32::from_be_bytes(self.octets()) == 0xc000000a
+        {
             return true;
         }
         !self.is_private()
@@ -577,7 +584,8 @@ impl Ipv4Addr {
     /// assert_eq!(Ipv4Addr::new(100, 127, 255, 255).is_shared(), true);
     /// assert_eq!(Ipv4Addr::new(100, 128, 0, 0).is_shared(), false);
     /// ```
-    pub fn is_shared(&self) -> bool {
+    #[rustc_const_unstable(feature = "const_ipv4", issue = "76205")]
+    pub const fn is_shared(&self) -> bool {
         self.octets()[0] == 100 && (self.octets()[1] & 0b1100_0000 == 0b0100_0000)
     }
 
@@ -609,7 +617,8 @@ impl Ipv4Addr {
     /// 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);
     /// ```
-    pub fn is_ietf_protocol_assignment(&self) -> bool {
+    #[rustc_const_unstable(feature = "const_ipv4", issue = "76205")]
+    pub const fn is_ietf_protocol_assignment(&self) -> bool {
         self.octets()[0] == 192 && self.octets()[1] == 0 && self.octets()[2] == 0
     }
 
@@ -632,7 +641,8 @@ impl Ipv4Addr {
     /// assert_eq!(Ipv4Addr::new(198, 19, 255, 255).is_benchmarking(), true);
     /// assert_eq!(Ipv4Addr::new(198, 20, 0, 0).is_benchmarking(), false);
     /// ```
-    pub fn is_benchmarking(&self) -> bool {
+    #[rustc_const_unstable(feature = "const_ipv4", issue = "76205")]
+    pub const fn is_benchmarking(&self) -> bool {
         self.octets()[0] == 198 && (self.octets()[1] & 0xfe) == 18
     }
 
@@ -664,7 +674,8 @@ impl Ipv4Addr {
     /// // The broadcast address is not considered as reserved for future use by this implementation
     /// assert_eq!(Ipv4Addr::new(255, 255, 255, 255).is_reserved(), false);
     /// ```
-    pub fn is_reserved(&self) -> bool {
+    #[rustc_const_unstable(feature = "const_ipv4", issue = "76205")]
+    pub const fn is_reserved(&self) -> bool {
         self.octets()[0] & 240 == 240 && !self.is_broadcast()
     }
 
@@ -685,8 +696,9 @@ impl Ipv4Addr {
     /// assert_eq!(Ipv4Addr::new(236, 168, 10, 65).is_multicast(), true);
     /// assert_eq!(Ipv4Addr::new(172, 16, 10, 65).is_multicast(), false);
     /// ```
+    #[rustc_const_unstable(feature = "const_ipv4", issue = "76205")]
     #[stable(since = "1.7.0", feature = "ip_17")]
-    pub fn is_multicast(&self) -> bool {
+    pub const fn is_multicast(&self) -> bool {
         self.octets()[0] >= 224 && self.octets()[0] <= 239
     }
 
@@ -705,9 +717,10 @@ impl Ipv4Addr {
     /// assert_eq!(Ipv4Addr::new(255, 255, 255, 255).is_broadcast(), true);
     /// assert_eq!(Ipv4Addr::new(236, 168, 10, 65).is_broadcast(), false);
     /// ```
+    #[rustc_const_unstable(feature = "const_ipv4", issue = "76205")]
     #[stable(since = "1.7.0", feature = "ip_17")]
-    pub fn is_broadcast(&self) -> bool {
-        self == &Self::BROADCAST
+    pub const fn is_broadcast(&self) -> bool {
+        u32::from_be_bytes(self.octets()) == u32::from_be_bytes(Self::BROADCAST.octets())
     }
 
     /// Returns [`true`] if this address is in a range designated for documentation.
@@ -731,8 +744,9 @@ impl Ipv4Addr {
     /// assert_eq!(Ipv4Addr::new(203, 0, 113, 6).is_documentation(), true);
     /// assert_eq!(Ipv4Addr::new(193, 34, 17, 19).is_documentation(), false);
     /// ```
+    #[rustc_const_unstable(feature = "const_ipv4", issue = "76205")]
     #[stable(since = "1.7.0", feature = "ip_17")]
-    pub fn is_documentation(&self) -> bool {
+    pub const fn is_documentation(&self) -> bool {
         match self.octets() {
             [192, 0, 2, _] => true,
             [198, 51, 100, _] => true,
@@ -760,10 +774,13 @@ impl Ipv4Addr {
     ///     Ipv6Addr::new(0, 0, 0, 0, 0, 0, 49152, 767)
     /// );
     /// ```
+    #[rustc_const_unstable(feature = "const_ipv4", issue = "76205")]
     #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn to_ipv6_compatible(&self) -> Ipv6Addr {
+    pub const fn to_ipv6_compatible(&self) -> Ipv6Addr {
         let [a, b, c, d] = self.octets();
-        Ipv6Addr::from([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, a, b, c, d])
+        Ipv6Addr {
+            inner: c::in6_addr { s6_addr: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, a, b, c, d] },
+        }
     }
 
     /// Converts this address to an IPv4-mapped [`IPv6` address].
@@ -780,10 +797,13 @@ impl Ipv4Addr {
     /// assert_eq!(Ipv4Addr::new(192, 0, 2, 255).to_ipv6_mapped(),
     ///            Ipv6Addr::new(0, 0, 0, 0, 0, 65535, 49152, 767));
     /// ```
+    #[rustc_const_unstable(feature = "const_ipv4", issue = "76205")]
     #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn to_ipv6_mapped(&self) -> Ipv6Addr {
+    pub const fn to_ipv6_mapped(&self) -> Ipv6Addr {
         let [a, b, c, d] = self.octets();
-        Ipv6Addr::from([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xFF, 0xFF, a, b, c, d])
+        Ipv6Addr {
+            inner: c::in6_addr { s6_addr: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xFF, 0xFF, a, b, c, d] },
+        }
     }
 }
 
diff --git a/src/test/ui/consts/std/net/ipv4.rs b/src/test/ui/consts/std/net/ipv4.rs
new file mode 100644
index 00000000000..8c676999ae7
--- /dev/null
+++ b/src/test/ui/consts/std/net/ipv4.rs
@@ -0,0 +1,58 @@
+// run-pass
+
+#![feature(ip)]
+#![feature(const_ipv4)]
+
+use std::net::{Ipv4Addr, Ipv6Addr};
+
+fn main() {
+    const IP_ADDRESS: Ipv4Addr = Ipv4Addr::new(127, 0, 0, 1);
+    assert_eq!(IP_ADDRESS, Ipv4Addr::LOCALHOST);
+
+    const OCTETS: [u8; 4] = IP_ADDRESS.octets();
+    assert_eq!(OCTETS, [127, 0, 0, 1]);
+
+    const IS_UNSPECIFIED : bool = IP_ADDRESS.is_unspecified();
+    assert!(!IS_UNSPECIFIED);
+
+    const IS_LOOPBACK : bool = IP_ADDRESS.is_loopback();
+    assert!(IS_LOOPBACK);
+
+    const IS_PRIVATE : bool = IP_ADDRESS.is_private();
+    assert!(!IS_PRIVATE);
+
+    const IS_LINK_LOCAL : bool = IP_ADDRESS.is_link_local();
+    assert!(!IS_LINK_LOCAL);
+
+    const IS_GLOBAL : bool = IP_ADDRESS.is_global();
+    assert!(!IS_GLOBAL);
+
+    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);
+
+    const IS_RESERVED : bool = IP_ADDRESS.is_reserved();
+    assert!(!IS_RESERVED);
+
+    const IS_MULTICAST : bool = IP_ADDRESS.is_multicast();
+    assert!(!IS_MULTICAST);
+
+    const IS_BROADCAST : bool = IP_ADDRESS.is_broadcast();
+    assert!(!IS_BROADCAST);
+
+    const IS_DOCUMENTATION : bool = IP_ADDRESS.is_documentation();
+    assert!(!IS_DOCUMENTATION);
+
+    const IP_V6_COMPATIBLE : Ipv6Addr = IP_ADDRESS.to_ipv6_compatible();
+    assert_eq!(IP_V6_COMPATIBLE,
+        Ipv6Addr::from([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 127, 0, 0, 1]));
+
+    const IP_V6_MAPPED : Ipv6Addr = IP_ADDRESS.to_ipv6_mapped();
+    assert_eq!(IP_V6_MAPPED,
+        Ipv6Addr::from([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 255, 255, 127, 0, 0, 1]));
+}