From 55e23db137bd659a4299abc29104eb643a5a0b1c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Linus=20F=C3=A4rnstrand?= <faern@faern.net>
Date: Sun, 1 Nov 2020 00:27:55 +0100
Subject: [PATCH 1/8] Represent SocketAddrV4 and SocketAddrV6 as Rust native
 encoding

---
 library/std/src/net/addr.rs        | 177 ++++++++++++++---------------
 library/std/src/sys/unix/net.rs    |   4 +-
 library/std/src/sys/windows/net.rs |   4 +-
 library/std/src/sys_common/net.rs  |  20 ++--
 4 files changed, 100 insertions(+), 105 deletions(-)

diff --git a/library/std/src/net/addr.rs b/library/std/src/net/addr.rs
index 81dd042425c1d..d724f7e7843b0 100644
--- a/library/std/src/net/addr.rs
+++ b/library/std/src/net/addr.rs
@@ -73,12 +73,11 @@ pub enum SocketAddr {
 /// assert_eq!(socket.ip(), &Ipv4Addr::new(127, 0, 0, 1));
 /// assert_eq!(socket.port(), 8080);
 /// ```
-#[derive(Copy)]
+#[derive(Copy, Clone, Eq, PartialEq)]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct SocketAddrV4 {
-    // Do not assume that this struct is implemented as the underlying system representation.
-    // The memory layout is not part of the stable interface that std exposes.
-    inner: c::sockaddr_in,
+    ip: Ipv4Addr,
+    port: u16,
 }
 
 /// An IPv6 socket address.
@@ -107,12 +106,13 @@ pub struct SocketAddrV4 {
 /// assert_eq!(socket.ip(), &Ipv6Addr::new(0x2001, 0xdb8, 0, 0, 0, 0, 0, 1));
 /// assert_eq!(socket.port(), 8080);
 /// ```
-#[derive(Copy)]
+#[derive(Copy, Clone, Eq, PartialEq)]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct SocketAddrV6 {
-    // Do not assume that this struct is implemented as the underlying system representation.
-    // The memory layout is not part of the stable interface that std exposes.
-    inner: c::sockaddr_in6,
+    ip: Ipv6Addr,
+    port: u16,
+    flowinfo: u32,
+    scope_id: u32,
 }
 
 impl SocketAddr {
@@ -131,7 +131,8 @@ impl SocketAddr {
     /// ```
     #[stable(feature = "ip_addr", since = "1.7.0")]
     #[must_use]
-    pub fn new(ip: IpAddr, port: u16) -> SocketAddr {
+    #[rustc_const_unstable(feature = "const_socketaddr", issue = "none")]
+    pub const fn new(ip: IpAddr, port: u16) -> SocketAddr {
         match ip {
             IpAddr::V4(a) => SocketAddr::V4(SocketAddrV4::new(a, port)),
             IpAddr::V6(a) => SocketAddr::V6(SocketAddrV6::new(a, port, 0, 0)),
@@ -277,15 +278,9 @@ impl SocketAddrV4 {
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     #[must_use]
-    pub fn new(ip: Ipv4Addr, port: u16) -> SocketAddrV4 {
-        SocketAddrV4 {
-            inner: c::sockaddr_in {
-                sin_family: c::AF_INET as c::sa_family_t,
-                sin_port: htons(port),
-                sin_addr: ip.into_inner(),
-                ..unsafe { mem::zeroed() }
-            },
-        }
+    #[rustc_const_unstable(feature = "const_socketaddr", issue = "none")]
+    pub const fn new(ip: Ipv4Addr, port: u16) -> SocketAddrV4 {
+        SocketAddrV4 { ip, port }
     }
 
     /// Returns the IP address associated with this socket address.
@@ -302,9 +297,7 @@ impl SocketAddrV4 {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_const_unstable(feature = "const_socketaddr", issue = "82485")]
     pub const fn ip(&self) -> &Ipv4Addr {
-        // SAFETY: `Ipv4Addr` is `#[repr(C)] struct { _: in_addr; }`.
-        // It is safe to cast from `&in_addr` to `&Ipv4Addr`.
-        unsafe { &*(&self.inner.sin_addr as *const c::in_addr as *const Ipv4Addr) }
+        &self.ip
     }
 
     /// Changes the IP address associated with this socket address.
@@ -320,7 +313,7 @@ impl SocketAddrV4 {
     /// ```
     #[stable(feature = "sockaddr_setters", since = "1.9.0")]
     pub fn set_ip(&mut self, new_ip: Ipv4Addr) {
-        self.inner.sin_addr = new_ip.into_inner()
+        self.ip = new_ip;
     }
 
     /// Returns the port number associated with this socket address.
@@ -337,7 +330,7 @@ impl SocketAddrV4 {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_const_unstable(feature = "const_socketaddr", issue = "82485")]
     pub const fn port(&self) -> u16 {
-        ntohs(self.inner.sin_port)
+        self.port
     }
 
     /// Changes the port number associated with this socket address.
@@ -353,7 +346,7 @@ impl SocketAddrV4 {
     /// ```
     #[stable(feature = "sockaddr_setters", since = "1.9.0")]
     pub fn set_port(&mut self, new_port: u16) {
-        self.inner.sin_port = htons(new_port);
+        self.port = new_port;
     }
 }
 
@@ -376,17 +369,9 @@ impl SocketAddrV6 {
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     #[must_use]
-    pub fn new(ip: Ipv6Addr, port: u16, flowinfo: u32, scope_id: u32) -> SocketAddrV6 {
-        SocketAddrV6 {
-            inner: c::sockaddr_in6 {
-                sin6_family: c::AF_INET6 as c::sa_family_t,
-                sin6_port: htons(port),
-                sin6_addr: *ip.as_inner(),
-                sin6_flowinfo: flowinfo,
-                sin6_scope_id: scope_id,
-                ..unsafe { mem::zeroed() }
-            },
-        }
+    #[rustc_const_unstable(feature = "const_socketaddr", issue = "none")]
+    pub const fn new(ip: Ipv6Addr, port: u16, flowinfo: u32, scope_id: u32) -> SocketAddrV6 {
+        SocketAddrV6 { ip, port, flowinfo, scope_id }
     }
 
     /// Returns the IP address associated with this socket address.
@@ -403,7 +388,7 @@ impl SocketAddrV6 {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_const_unstable(feature = "const_socketaddr", issue = "82485")]
     pub const fn ip(&self) -> &Ipv6Addr {
-        unsafe { &*(&self.inner.sin6_addr as *const c::in6_addr as *const Ipv6Addr) }
+        &self.ip
     }
 
     /// Changes the IP address associated with this socket address.
@@ -419,7 +404,7 @@ impl SocketAddrV6 {
     /// ```
     #[stable(feature = "sockaddr_setters", since = "1.9.0")]
     pub fn set_ip(&mut self, new_ip: Ipv6Addr) {
-        self.inner.sin6_addr = *new_ip.as_inner()
+        self.ip = new_ip;
     }
 
     /// Returns the port number associated with this socket address.
@@ -436,7 +421,7 @@ impl SocketAddrV6 {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_const_unstable(feature = "const_socketaddr", issue = "82485")]
     pub const fn port(&self) -> u16 {
-        ntohs(self.inner.sin6_port)
+        self.port
     }
 
     /// Changes the port number associated with this socket address.
@@ -452,7 +437,7 @@ impl SocketAddrV6 {
     /// ```
     #[stable(feature = "sockaddr_setters", since = "1.9.0")]
     pub fn set_port(&mut self, new_port: u16) {
-        self.inner.sin6_port = htons(new_port);
+        self.port = new_port;
     }
 
     /// Returns the flow information associated with this address.
@@ -479,7 +464,7 @@ impl SocketAddrV6 {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_const_unstable(feature = "const_socketaddr", issue = "82485")]
     pub const fn flowinfo(&self) -> u32 {
-        self.inner.sin6_flowinfo
+        self.flowinfo
     }
 
     /// Changes the flow information associated with this socket address.
@@ -497,7 +482,7 @@ impl SocketAddrV6 {
     /// ```
     #[stable(feature = "sockaddr_setters", since = "1.9.0")]
     pub fn set_flowinfo(&mut self, new_flowinfo: u32) {
-        self.inner.sin6_flowinfo = new_flowinfo;
+        self.flowinfo = new_flowinfo;
     }
 
     /// Returns the scope ID associated with this address.
@@ -519,7 +504,7 @@ impl SocketAddrV6 {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_const_unstable(feature = "const_socketaddr", issue = "82485")]
     pub const fn scope_id(&self) -> u32 {
-        self.inner.sin6_scope_id
+        self.scope_id
     }
 
     /// Changes the scope ID associated with this socket address.
@@ -537,19 +522,51 @@ impl SocketAddrV6 {
     /// ```
     #[stable(feature = "sockaddr_setters", since = "1.9.0")]
     pub fn set_scope_id(&mut self, new_scope_id: u32) {
-        self.inner.sin6_scope_id = new_scope_id;
+        self.scope_id = new_scope_id;
     }
 }
 
 impl FromInner<c::sockaddr_in> for SocketAddrV4 {
     fn from_inner(addr: c::sockaddr_in) -> SocketAddrV4 {
-        SocketAddrV4 { inner: addr }
+        SocketAddrV4 {
+            ip: unsafe { *(&addr.sin_addr as *const c::in_addr as *const Ipv4Addr) },
+            port: ntohs(addr.sin_port),
+        }
     }
 }
 
 impl FromInner<c::sockaddr_in6> for SocketAddrV6 {
     fn from_inner(addr: c::sockaddr_in6) -> SocketAddrV6 {
-        SocketAddrV6 { inner: addr }
+        SocketAddrV6 {
+            ip: unsafe { *(&addr.sin6_addr as *const c::in6_addr as *const Ipv6Addr) },
+            port: ntohs(addr.sin6_port),
+            flowinfo: addr.sin6_flowinfo,
+            scope_id: addr.sin6_scope_id,
+        }
+    }
+}
+
+impl IntoInner<c::sockaddr_in> for SocketAddrV4 {
+    fn into_inner(self) -> c::sockaddr_in {
+        c::sockaddr_in {
+            sin_family: c::AF_INET as c::sa_family_t,
+            sin_port: htons(self.port),
+            sin_addr: self.ip.into_inner(),
+            ..unsafe { mem::zeroed() }
+        }
+    }
+}
+
+impl IntoInner<c::sockaddr_in6> for SocketAddrV6 {
+    fn into_inner(self) -> c::sockaddr_in6 {
+        c::sockaddr_in6 {
+            sin6_family: c::AF_INET6 as c::sa_family_t,
+            sin6_port: htons(self.port),
+            sin6_addr: *self.ip.as_inner(),
+            sin6_flowinfo: self.flowinfo,
+            sin6_scope_id: self.scope_id,
+            ..unsafe { mem::zeroed() }
+        }
     }
 }
 
@@ -582,14 +599,32 @@ impl<I: Into<IpAddr>> From<(I, u16)> for SocketAddr {
     }
 }
 
-impl<'a> IntoInner<(*const c::sockaddr, c::socklen_t)> for &'a SocketAddr {
-    fn into_inner(self) -> (*const c::sockaddr, c::socklen_t) {
+/// A type with the same memory layout as `c::sockaddr`. Used in converting Rust level
+/// SocketAddr* types into their system representation. The benefit of this specific
+/// type over using `c::sockaddr_storage` is that this type is exactly as large as it
+/// needs to be and not a lot larger. And it can be initialized more cleanly from Rust.
+#[repr(C)]
+pub(crate) union SocketAddrCRepr {
+    v4: c::sockaddr_in,
+    v6: c::sockaddr_in6,
+}
+
+impl SocketAddrCRepr {
+    pub fn as_ptr(&self) -> *const c::sockaddr {
+        self as *const _ as *const c::sockaddr
+    }
+}
+
+impl<'a> IntoInner<(SocketAddrCRepr, c::socklen_t)> for &'a SocketAddr {
+    fn into_inner(self) -> (SocketAddrCRepr, c::socklen_t) {
         match *self {
             SocketAddr::V4(ref a) => {
-                (a as *const _ as *const _, mem::size_of_val(a) as c::socklen_t)
+                let sockaddr = SocketAddrCRepr { v4: a.into_inner() };
+                (sockaddr, mem::size_of::<c::sockaddr_in>() as c::socklen_t)
             }
             SocketAddr::V6(ref a) => {
-                (a as *const _ as *const _, mem::size_of_val(a) as c::socklen_t)
+                let sockaddr = SocketAddrCRepr { v6: a.into_inner() };
+                (sockaddr, mem::size_of::<c::sockaddr_in6>() as c::socklen_t)
             }
         }
     }
@@ -688,40 +723,6 @@ impl fmt::Debug for SocketAddrV6 {
     }
 }
 
-#[stable(feature = "rust1", since = "1.0.0")]
-impl Clone for SocketAddrV4 {
-    fn clone(&self) -> SocketAddrV4 {
-        *self
-    }
-}
-#[stable(feature = "rust1", since = "1.0.0")]
-impl Clone for SocketAddrV6 {
-    fn clone(&self) -> SocketAddrV6 {
-        *self
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl PartialEq for SocketAddrV4 {
-    fn eq(&self, other: &SocketAddrV4) -> bool {
-        self.inner.sin_port == other.inner.sin_port
-            && self.inner.sin_addr.s_addr == other.inner.sin_addr.s_addr
-    }
-}
-#[stable(feature = "rust1", since = "1.0.0")]
-impl PartialEq for SocketAddrV6 {
-    fn eq(&self, other: &SocketAddrV6) -> bool {
-        self.inner.sin6_port == other.inner.sin6_port
-            && self.inner.sin6_addr.s6_addr == other.inner.sin6_addr.s6_addr
-            && self.inner.sin6_flowinfo == other.inner.sin6_flowinfo
-            && self.inner.sin6_scope_id == other.inner.sin6_scope_id
-    }
-}
-#[stable(feature = "rust1", since = "1.0.0")]
-impl Eq for SocketAddrV4 {}
-#[stable(feature = "rust1", since = "1.0.0")]
-impl Eq for SocketAddrV6 {}
-
 #[stable(feature = "socketaddr_ordering", since = "1.45.0")]
 impl PartialOrd for SocketAddrV4 {
     fn partial_cmp(&self, other: &SocketAddrV4) -> Option<Ordering> {
@@ -753,19 +754,13 @@ impl Ord for SocketAddrV6 {
 #[stable(feature = "rust1", since = "1.0.0")]
 impl hash::Hash for SocketAddrV4 {
     fn hash<H: hash::Hasher>(&self, s: &mut H) {
-        (self.inner.sin_port, self.inner.sin_addr.s_addr).hash(s)
+        (self.port, self.ip).hash(s)
     }
 }
 #[stable(feature = "rust1", since = "1.0.0")]
 impl hash::Hash for SocketAddrV6 {
     fn hash<H: hash::Hasher>(&self, s: &mut H) {
-        (
-            self.inner.sin6_port,
-            &self.inner.sin6_addr.s6_addr,
-            self.inner.sin6_flowinfo,
-            self.inner.sin6_scope_id,
-        )
-            .hash(s)
+        (self.port, &self.ip, self.flowinfo, self.scope_id).hash(s)
     }
 }
 
diff --git a/library/std/src/sys/unix/net.rs b/library/std/src/sys/unix/net.rs
index a1bbc2d87b640..462a45b01ab49 100644
--- a/library/std/src/sys/unix/net.rs
+++ b/library/std/src/sys/unix/net.rs
@@ -139,8 +139,8 @@ impl Socket {
     pub fn connect_timeout(&self, addr: &SocketAddr, timeout: Duration) -> io::Result<()> {
         self.set_nonblocking(true)?;
         let r = unsafe {
-            let (addrp, len) = addr.into_inner();
-            cvt(libc::connect(self.as_raw_fd(), addrp, len))
+            let (addr, len) = addr.into_inner();
+            cvt(libc::connect(self.as_raw_fd(), addr.as_ptr(), len))
         };
         self.set_nonblocking(false)?;
 
diff --git a/library/std/src/sys/windows/net.rs b/library/std/src/sys/windows/net.rs
index d1e72cd54437c..e0701a498fad7 100644
--- a/library/std/src/sys/windows/net.rs
+++ b/library/std/src/sys/windows/net.rs
@@ -143,8 +143,8 @@ impl Socket {
     pub fn connect_timeout(&self, addr: &SocketAddr, timeout: Duration) -> io::Result<()> {
         self.set_nonblocking(true)?;
         let result = {
-            let (addrp, len) = addr.into_inner();
-            let result = unsafe { c::connect(self.as_raw_socket(), addrp, len) };
+            let (addr, len) = addr.into_inner();
+            let result = unsafe { c::connect(self.as_raw_socket(), addr.as_ptr(), len) };
             cvt(result).map(drop)
         };
         self.set_nonblocking(false)?;
diff --git a/library/std/src/sys_common/net.rs b/library/std/src/sys_common/net.rs
index f5730a2cea52b..8c4349bf7ed9e 100644
--- a/library/std/src/sys_common/net.rs
+++ b/library/std/src/sys_common/net.rs
@@ -224,8 +224,8 @@ impl TcpStream {
 
         let sock = Socket::new(addr, c::SOCK_STREAM)?;
 
-        let (addrp, len) = addr.into_inner();
-        cvt_r(|| unsafe { c::connect(sock.as_raw(), addrp, len) })?;
+        let (addr, len) = addr.into_inner();
+        cvt_r(|| unsafe { c::connect(sock.as_raw(), addr.as_ptr(), len) })?;
         Ok(TcpStream { inner: sock })
     }
 
@@ -395,8 +395,8 @@ impl TcpListener {
         setsockopt(&sock, c::SOL_SOCKET, c::SO_REUSEADDR, 1 as c_int)?;
 
         // Bind our new socket
-        let (addrp, len) = addr.into_inner();
-        cvt(unsafe { c::bind(sock.as_raw(), addrp, len as _) })?;
+        let (addr, len) = addr.into_inner();
+        cvt(unsafe { c::bind(sock.as_raw(), addr.as_ptr(), len as _) })?;
 
         cfg_if::cfg_if! {
             if #[cfg(target_os = "horizon")] {
@@ -500,8 +500,8 @@ impl UdpSocket {
         init();
 
         let sock = Socket::new(addr, c::SOCK_DGRAM)?;
-        let (addrp, len) = addr.into_inner();
-        cvt(unsafe { c::bind(sock.as_raw(), addrp, len as _) })?;
+        let (addr, len) = addr.into_inner();
+        cvt(unsafe { c::bind(sock.as_raw(), addr.as_ptr(), len as _) })?;
         Ok(UdpSocket { inner: sock })
     }
 
@@ -531,14 +531,14 @@ impl UdpSocket {
 
     pub fn send_to(&self, buf: &[u8], dst: &SocketAddr) -> io::Result<usize> {
         let len = cmp::min(buf.len(), <wrlen_t>::MAX as usize) as wrlen_t;
-        let (dstp, dstlen) = dst.into_inner();
+        let (dst, dstlen) = dst.into_inner();
         let ret = cvt(unsafe {
             c::sendto(
                 self.inner.as_raw(),
                 buf.as_ptr() as *const c_void,
                 len,
                 MSG_NOSIGNAL,
-                dstp,
+                dst.as_ptr(),
                 dstlen,
             )
         })?;
@@ -677,8 +677,8 @@ impl UdpSocket {
     }
 
     pub fn connect(&self, addr: io::Result<&SocketAddr>) -> io::Result<()> {
-        let (addrp, len) = addr?.into_inner();
-        cvt_r(|| unsafe { c::connect(self.inner.as_raw(), addrp, len) }).map(drop)
+        let (addr, len) = addr?.into_inner();
+        cvt_r(|| unsafe { c::connect(self.inner.as_raw(), addr.as_ptr(), len) }).map(drop)
     }
 }
 

From 2e6256b2431c3b3713fa33ab46f293dbd07dec93 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Linus=20F=C3=A4rnstrand?= <faern@faern.net>
Date: Tue, 3 Nov 2020 00:40:27 +0100
Subject: [PATCH 2/8] Implement IpV{4,6}Addr structs with native Rust encoding

---
 library/std/src/net/addr.rs       |  11 +--
 library/std/src/net/ip.rs         | 138 ++++++++----------------------
 library/std/src/sys_common/net.rs |   6 +-
 3 files changed, 41 insertions(+), 114 deletions(-)

diff --git a/library/std/src/net/addr.rs b/library/std/src/net/addr.rs
index d724f7e7843b0..bfda46a802b38 100644
--- a/library/std/src/net/addr.rs
+++ b/library/std/src/net/addr.rs
@@ -12,7 +12,7 @@ use crate::option;
 use crate::slice;
 use crate::sys::net::netc as c;
 use crate::sys_common::net::LookupHost;
-use crate::sys_common::{AsInner, FromInner, IntoInner};
+use crate::sys_common::{FromInner, IntoInner};
 use crate::vec;
 
 /// An internet socket address, either IPv4 or IPv6.
@@ -528,17 +528,14 @@ impl SocketAddrV6 {
 
 impl FromInner<c::sockaddr_in> for SocketAddrV4 {
     fn from_inner(addr: c::sockaddr_in) -> SocketAddrV4 {
-        SocketAddrV4 {
-            ip: unsafe { *(&addr.sin_addr as *const c::in_addr as *const Ipv4Addr) },
-            port: ntohs(addr.sin_port),
-        }
+        SocketAddrV4 { ip: Ipv4Addr::from_inner(addr.sin_addr), port: ntohs(addr.sin_port) }
     }
 }
 
 impl FromInner<c::sockaddr_in6> for SocketAddrV6 {
     fn from_inner(addr: c::sockaddr_in6) -> SocketAddrV6 {
         SocketAddrV6 {
-            ip: unsafe { *(&addr.sin6_addr as *const c::in6_addr as *const Ipv6Addr) },
+            ip: Ipv6Addr::from_inner(addr.sin6_addr),
             port: ntohs(addr.sin6_port),
             flowinfo: addr.sin6_flowinfo,
             scope_id: addr.sin6_scope_id,
@@ -562,7 +559,7 @@ impl IntoInner<c::sockaddr_in6> for SocketAddrV6 {
         c::sockaddr_in6 {
             sin6_family: c::AF_INET6 as c::sa_family_t,
             sin6_port: htons(self.port),
-            sin6_addr: *self.ip.as_inner(),
+            sin6_addr: self.ip.into_inner(),
             sin6_flowinfo: self.flowinfo,
             sin6_scope_id: self.scope_id,
             ..unsafe { mem::zeroed() }
diff --git a/library/std/src/net/ip.rs b/library/std/src/net/ip.rs
index 438bae01b60d2..1d49024f13e15 100644
--- a/library/std/src/net/ip.rs
+++ b/library/std/src/net/ip.rs
@@ -4,11 +4,10 @@ mod tests;
 
 use crate::cmp::Ordering;
 use crate::fmt::{self, Write as FmtWrite};
-use crate::hash;
 use crate::io::Write as IoWrite;
 use crate::mem::transmute;
 use crate::sys::net::netc as c;
-use crate::sys_common::{AsInner, FromInner, IntoInner};
+use crate::sys_common::{FromInner, IntoInner};
 
 /// An IP address, either IPv4 or IPv6.
 ///
@@ -77,10 +76,10 @@ pub enum IpAddr {
 /// assert!("0000000.0.0.0".parse::<Ipv4Addr>().is_err()); // first octet is a zero in octal
 /// assert!("0xcb.0x0.0x71.0x00".parse::<Ipv4Addr>().is_err()); // all octets are in hex
 /// ```
-#[derive(Copy)]
+#[derive(Copy, Clone, PartialEq, Eq, Hash)]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct Ipv4Addr {
-    inner: c::in_addr,
+    octets: [u8; 4],
 }
 
 /// An IPv6 address.
@@ -162,10 +161,10 @@ pub struct Ipv4Addr {
 /// assert_eq!("::1".parse(), Ok(localhost));
 /// assert_eq!(localhost.is_loopback(), true);
 /// ```
-#[derive(Copy)]
+#[derive(Copy, Clone, PartialEq, Eq, Hash)]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct Ipv6Addr {
-    inner: c::in6_addr,
+    octets: [u8; 16],
 }
 
 /// Scope of an [IPv6 multicast address] as defined in [IETF RFC 7346 section 2].
@@ -461,9 +460,7 @@ impl Ipv4Addr {
     #[must_use]
     #[inline]
     pub const fn new(a: u8, b: u8, c: u8, d: u8) -> Ipv4Addr {
-        // `s_addr` is stored as BE on all machine and the array is in BE order.
-        // So the native endian conversion method is used so that it's never swapped.
-        Ipv4Addr { inner: c::in_addr { s_addr: u32::from_ne_bytes([a, b, c, d]) } }
+        Ipv4Addr { octets: [a, b, c, d] }
     }
 
     /// An IPv4 address with the address pointing to localhost: `127.0.0.1`
@@ -523,8 +520,7 @@ impl Ipv4Addr {
     #[must_use]
     #[inline]
     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()
+        self.octets
     }
 
     /// Returns [`true`] for the special 'unspecified' address (`0.0.0.0`).
@@ -547,7 +543,7 @@ impl Ipv4Addr {
     #[must_use]
     #[inline]
     pub const fn is_unspecified(&self) -> bool {
-        self.inner.s_addr == 0
+        u32::from_be_bytes(self.octets) == 0
     }
 
     /// Returns [`true`] if this is a loopback address (`127.0.0.0/8`).
@@ -910,9 +906,7 @@ impl Ipv4Addr {
     #[inline]
     pub const fn to_ipv6_compatible(&self) -> Ipv6Addr {
         let [a, b, c, d] = self.octets();
-        Ipv6Addr {
-            inner: c::in6_addr { s6_addr: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, a, b, c, d] },
-        }
+        Ipv6Addr { octets: [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].
@@ -937,9 +931,7 @@ impl Ipv4Addr {
     #[inline]
     pub const fn to_ipv6_mapped(&self) -> Ipv6Addr {
         let [a, b, c, d] = self.octets();
-        Ipv6Addr {
-            inner: c::in6_addr { s6_addr: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xFF, 0xFF, a, b, c, d] },
-        }
+        Ipv6Addr { octets: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xFF, 0xFF, a, b, c, d] }
     }
 }
 
@@ -1034,22 +1026,6 @@ impl fmt::Debug for Ipv4Addr {
     }
 }
 
-#[stable(feature = "rust1", since = "1.0.0")]
-impl Clone for Ipv4Addr {
-    #[inline]
-    fn clone(&self) -> Ipv4Addr {
-        *self
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl PartialEq for Ipv4Addr {
-    #[inline]
-    fn eq(&self, other: &Ipv4Addr) -> bool {
-        self.inner.s_addr == other.inner.s_addr
-    }
-}
-
 #[stable(feature = "ip_cmp", since = "1.16.0")]
 impl PartialEq<Ipv4Addr> for IpAddr {
     #[inline]
@@ -1072,21 +1048,6 @@ impl PartialEq<IpAddr> for Ipv4Addr {
     }
 }
 
-#[stable(feature = "rust1", since = "1.0.0")]
-impl Eq for Ipv4Addr {}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl hash::Hash for Ipv4Addr {
-    #[inline]
-    fn hash<H: hash::Hasher>(&self, s: &mut H) {
-        // NOTE:
-        // * hash in big endian order
-        // * in netbsd, `in_addr` has `repr(packed)`, we need to
-        //   copy `s_addr` to avoid unsafe borrowing
-        { self.inner.s_addr }.hash(s)
-    }
-}
-
 #[stable(feature = "rust1", since = "1.0.0")]
 impl PartialOrd for Ipv4Addr {
     #[inline]
@@ -1121,15 +1082,21 @@ impl PartialOrd<IpAddr> for Ipv4Addr {
 impl Ord for Ipv4Addr {
     #[inline]
     fn cmp(&self, other: &Ipv4Addr) -> Ordering {
-        // Compare as native endian
-        u32::from_be(self.inner.s_addr).cmp(&u32::from_be(other.inner.s_addr))
+        self.octets.cmp(&other.octets)
     }
 }
 
 impl IntoInner<c::in_addr> for Ipv4Addr {
     #[inline]
     fn into_inner(self) -> c::in_addr {
-        self.inner
+        // `s_addr` is stored as BE on all machines and the array is in BE order.
+        // So the native endian conversion method is used so that it's never swapped.
+        c::in_addr { s_addr: u32::from_ne_bytes(self.octets) }
+    }
+}
+impl FromInner<c::in_addr> for Ipv4Addr {
+    fn from_inner(addr: c::in_addr) -> Ipv4Addr {
+        Ipv4Addr { octets: addr.s_addr.to_ne_bytes() }
     }
 }
 
@@ -1147,8 +1114,7 @@ impl From<Ipv4Addr> for u32 {
     /// ```
     #[inline]
     fn from(ip: Ipv4Addr) -> u32 {
-        let ip = ip.octets();
-        u32::from_be_bytes(ip)
+        u32::from_be_bytes(ip.octets)
     }
 }
 
@@ -1166,7 +1132,7 @@ impl From<u32> for Ipv4Addr {
     /// ```
     #[inline]
     fn from(ip: u32) -> Ipv4Addr {
-        Ipv4Addr::from(ip.to_be_bytes())
+        Ipv4Addr { octets: ip.to_be_bytes() }
     }
 }
 
@@ -1184,7 +1150,7 @@ impl From<[u8; 4]> for Ipv4Addr {
     /// ```
     #[inline]
     fn from(octets: [u8; 4]) -> Ipv4Addr {
-        Ipv4Addr::new(octets[0], octets[1], octets[2], octets[3])
+        Ipv4Addr { octets }
     }
 }
 
@@ -1234,13 +1200,9 @@ impl Ipv6Addr {
             h.to_be(),
         ];
         Ipv6Addr {
-            inner: c::in6_addr {
-                // All elements in `addr16` are big endian.
-                // SAFETY: `[u16; 8]` is always safe to transmute to `[u8; 16]`.
-                // rustc_allow_const_fn_unstable: the transmute could be written as stable const
-                // code, but that leads to worse code generation (#75085)
-                s6_addr: unsafe { transmute::<_, [u8; 16]>(addr16) },
-            },
+            // All elements in `addr16` are big endian.
+            // SAFETY: `[u16; 8]` is always safe to transmute to `[u8; 16]`.
+            octets: unsafe { transmute::<_, [u8; 16]>(addr16) },
         }
     }
 
@@ -1285,11 +1247,9 @@ impl Ipv6Addr {
     #[must_use]
     #[inline]
     pub const fn segments(&self) -> [u16; 8] {
-        // All elements in `s6_addr` must be big endian.
+        // All elements in `self.octets` must be big endian.
         // SAFETY: `[u8; 16]` is always safe to transmute to `[u16; 8]`.
-        // rustc_allow_const_fn_unstable: the transmute could be written as stable const code, but
-        // that leads to worse code generation (#75085)
-        let [a, b, c, d, e, f, g, h] = unsafe { transmute::<_, [u16; 8]>(self.inner.s6_addr) };
+        let [a, b, c, d, e, f, g, h] = unsafe { transmute::<_, [u16; 8]>(self.octets) };
         // We want native endian u16
         [
             u16::from_be(a),
@@ -1748,7 +1708,7 @@ impl Ipv6Addr {
     #[must_use]
     #[inline]
     pub const fn octets(&self) -> [u8; 16] {
-        self.inner.s6_addr
+        self.octets
     }
 }
 
@@ -1856,22 +1816,6 @@ impl fmt::Debug for Ipv6Addr {
     }
 }
 
-#[stable(feature = "rust1", since = "1.0.0")]
-impl Clone for Ipv6Addr {
-    #[inline]
-    fn clone(&self) -> Ipv6Addr {
-        *self
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl PartialEq for Ipv6Addr {
-    #[inline]
-    fn eq(&self, other: &Ipv6Addr) -> bool {
-        self.inner.s6_addr == other.inner.s6_addr
-    }
-}
-
 #[stable(feature = "ip_cmp", since = "1.16.0")]
 impl PartialEq<IpAddr> for Ipv6Addr {
     #[inline]
@@ -1894,17 +1838,6 @@ impl PartialEq<Ipv6Addr> for IpAddr {
     }
 }
 
-#[stable(feature = "rust1", since = "1.0.0")]
-impl Eq for Ipv6Addr {}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl hash::Hash for Ipv6Addr {
-    #[inline]
-    fn hash<H: hash::Hasher>(&self, s: &mut H) {
-        self.inner.s6_addr.hash(s)
-    }
-}
-
 #[stable(feature = "rust1", since = "1.0.0")]
 impl PartialOrd for Ipv6Addr {
     #[inline]
@@ -1943,16 +1876,15 @@ impl Ord for Ipv6Addr {
     }
 }
 
-impl AsInner<c::in6_addr> for Ipv6Addr {
-    #[inline]
-    fn as_inner(&self) -> &c::in6_addr {
-        &self.inner
+impl IntoInner<c::in6_addr> for Ipv6Addr {
+    fn into_inner(self) -> c::in6_addr {
+        c::in6_addr { s6_addr: self.octets }
     }
 }
 impl FromInner<c::in6_addr> for Ipv6Addr {
     #[inline]
     fn from_inner(addr: c::in6_addr) -> Ipv6Addr {
-        Ipv6Addr { inner: addr }
+        Ipv6Addr { octets: addr.s6_addr }
     }
 }
 
@@ -1973,8 +1905,7 @@ impl From<Ipv6Addr> for u128 {
     /// ```
     #[inline]
     fn from(ip: Ipv6Addr) -> u128 {
-        let ip = ip.octets();
-        u128::from_be_bytes(ip)
+        u128::from_be_bytes(ip.octets)
     }
 }
 #[stable(feature = "i128", since = "1.26.0")]
@@ -2025,8 +1956,7 @@ impl From<[u8; 16]> for Ipv6Addr {
     /// ```
     #[inline]
     fn from(octets: [u8; 16]) -> Ipv6Addr {
-        let inner = c::in6_addr { s6_addr: octets };
-        Ipv6Addr::from_inner(inner)
+        Ipv6Addr { octets }
     }
 }
 
diff --git a/library/std/src/sys_common/net.rs b/library/std/src/sys_common/net.rs
index 8c4349bf7ed9e..e49337999d2c5 100644
--- a/library/std/src/sys_common/net.rs
+++ b/library/std/src/sys_common/net.rs
@@ -10,7 +10,7 @@ use crate::net::{Ipv4Addr, Ipv6Addr, Shutdown, SocketAddr};
 use crate::ptr;
 use crate::sys::net::netc as c;
 use crate::sys::net::{cvt, cvt_gai, cvt_r, init, wrlen_t, Socket};
-use crate::sys_common::{AsInner, FromInner, IntoInner};
+use crate::sys_common::{FromInner, IntoInner};
 use crate::time::Duration;
 
 use libc::{c_int, c_void};
@@ -621,7 +621,7 @@ impl UdpSocket {
 
     pub fn join_multicast_v6(&self, multiaddr: &Ipv6Addr, interface: u32) -> io::Result<()> {
         let mreq = c::ipv6_mreq {
-            ipv6mr_multiaddr: *multiaddr.as_inner(),
+            ipv6mr_multiaddr: multiaddr.into_inner(),
             ipv6mr_interface: to_ipv6mr_interface(interface),
         };
         setsockopt(&self.inner, c::IPPROTO_IPV6, IPV6_ADD_MEMBERSHIP, mreq)
@@ -637,7 +637,7 @@ impl UdpSocket {
 
     pub fn leave_multicast_v6(&self, multiaddr: &Ipv6Addr, interface: u32) -> io::Result<()> {
         let mreq = c::ipv6_mreq {
-            ipv6mr_multiaddr: *multiaddr.as_inner(),
+            ipv6mr_multiaddr: multiaddr.into_inner(),
             ipv6mr_interface: to_ipv6mr_interface(interface),
         };
         setsockopt(&self.inner, c::IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP, mreq)

From 8cd73519621513fe75b915e8c37c87f128b453dd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Linus=20F=C3=A4rnstrand?= <faern@faern.net>
Date: Tue, 3 Nov 2020 01:08:31 +0100
Subject: [PATCH 3/8] Remove ntohs/htons in favor of to_be/from_be

---
 library/std/src/net/addr.rs | 10 +++++-----
 library/std/src/net/mod.rs  |  9 ---------
 2 files changed, 5 insertions(+), 14 deletions(-)

diff --git a/library/std/src/net/addr.rs b/library/std/src/net/addr.rs
index bfda46a802b38..4b5c5d03465be 100644
--- a/library/std/src/net/addr.rs
+++ b/library/std/src/net/addr.rs
@@ -7,7 +7,7 @@ use crate::hash;
 use crate::io::{self, Write};
 use crate::iter;
 use crate::mem;
-use crate::net::{htons, ntohs, IpAddr, Ipv4Addr, Ipv6Addr};
+use crate::net::{IpAddr, Ipv4Addr, Ipv6Addr};
 use crate::option;
 use crate::slice;
 use crate::sys::net::netc as c;
@@ -528,7 +528,7 @@ impl SocketAddrV6 {
 
 impl FromInner<c::sockaddr_in> for SocketAddrV4 {
     fn from_inner(addr: c::sockaddr_in) -> SocketAddrV4 {
-        SocketAddrV4 { ip: Ipv4Addr::from_inner(addr.sin_addr), port: ntohs(addr.sin_port) }
+        SocketAddrV4 { ip: Ipv4Addr::from_inner(addr.sin_addr), port: u16::from_be(addr.sin_port) }
     }
 }
 
@@ -536,7 +536,7 @@ impl FromInner<c::sockaddr_in6> for SocketAddrV6 {
     fn from_inner(addr: c::sockaddr_in6) -> SocketAddrV6 {
         SocketAddrV6 {
             ip: Ipv6Addr::from_inner(addr.sin6_addr),
-            port: ntohs(addr.sin6_port),
+            port: u16::from_be(addr.sin6_port),
             flowinfo: addr.sin6_flowinfo,
             scope_id: addr.sin6_scope_id,
         }
@@ -547,7 +547,7 @@ impl IntoInner<c::sockaddr_in> for SocketAddrV4 {
     fn into_inner(self) -> c::sockaddr_in {
         c::sockaddr_in {
             sin_family: c::AF_INET as c::sa_family_t,
-            sin_port: htons(self.port),
+            sin_port: self.port.to_be(),
             sin_addr: self.ip.into_inner(),
             ..unsafe { mem::zeroed() }
         }
@@ -558,7 +558,7 @@ impl IntoInner<c::sockaddr_in6> for SocketAddrV6 {
     fn into_inner(self) -> c::sockaddr_in6 {
         c::sockaddr_in6 {
             sin6_family: c::AF_INET6 as c::sa_family_t,
-            sin6_port: htons(self.port),
+            sin6_port: self.port.to_be(),
             sin6_addr: self.ip.into_inner(),
             sin6_flowinfo: self.flowinfo,
             sin6_scope_id: self.scope_id,
diff --git a/library/std/src/net/mod.rs b/library/std/src/net/mod.rs
index 9ed4a98f943cd..e7a40bdaf8e99 100644
--- a/library/std/src/net/mod.rs
+++ b/library/std/src/net/mod.rs
@@ -69,15 +69,6 @@ pub enum Shutdown {
     Both,
 }
 
-#[inline]
-const fn htons(i: u16) -> u16 {
-    i.to_be()
-}
-#[inline]
-const fn ntohs(i: u16) -> u16 {
-    u16::from_be(i)
-}
-
 fn each_addr<A: ToSocketAddrs, F, T>(addr: A, mut f: F) -> io::Result<T>
 where
     F: FnMut(io::Result<&SocketAddr>) -> io::Result<T>,

From 230441e8ab2fed8a03efbf1ccaabe06e922fc61a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Linus=20F=C3=A4rnstrand?= <faern@faern.net>
Date: Sun, 29 Nov 2020 21:57:14 +0100
Subject: [PATCH 4/8] Add IP structural_match tests

---
 library/std/src/net/ip/tests.rs | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/library/std/src/net/ip/tests.rs b/library/std/src/net/ip/tests.rs
index 7956c6a25e495..c29509331d7a9 100644
--- a/library/std/src/net/ip/tests.rs
+++ b/library/std/src/net/ip/tests.rs
@@ -944,3 +944,26 @@ fn ip_const() {
     const IS_IP_V6: bool = IP_ADDRESS.is_ipv6();
     assert!(!IS_IP_V6);
 }
+
+#[test]
+fn structural_match() {
+    // test that all IP types can be structurally matched upon
+
+    const IPV4: Ipv4Addr = Ipv4Addr::LOCALHOST;
+    match IPV4 {
+        Ipv4Addr::LOCALHOST => {}
+        _ => unreachable!(),
+    }
+
+    const IPV6: Ipv6Addr = Ipv6Addr::LOCALHOST;
+    match IPV6 {
+        Ipv6Addr::LOCALHOST => {}
+        _ => unreachable!(),
+    }
+
+    const IP: IpAddr = IpAddr::V4(Ipv4Addr::LOCALHOST);
+    match IP {
+        IpAddr::V4(Ipv4Addr::LOCALHOST) => {}
+        _ => unreachable!(),
+    }
+}

From a344d10810187430811b43a71ad9b742d25f9b37 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Linus=20F=C3=A4rnstrand?= <faern@faern.net>
Date: Thu, 23 Jun 2022 19:03:32 +0200
Subject: [PATCH 5/8] Assign issue number to the new const_socketaddr

---
 library/std/src/net/addr.rs | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/library/std/src/net/addr.rs b/library/std/src/net/addr.rs
index 4b5c5d03465be..13d85f2303502 100644
--- a/library/std/src/net/addr.rs
+++ b/library/std/src/net/addr.rs
@@ -131,7 +131,7 @@ impl SocketAddr {
     /// ```
     #[stable(feature = "ip_addr", since = "1.7.0")]
     #[must_use]
-    #[rustc_const_unstable(feature = "const_socketaddr", issue = "none")]
+    #[rustc_const_unstable(feature = "const_socketaddr", issue = "82485")]
     pub const fn new(ip: IpAddr, port: u16) -> SocketAddr {
         match ip {
             IpAddr::V4(a) => SocketAddr::V4(SocketAddrV4::new(a, port)),
@@ -278,7 +278,7 @@ impl SocketAddrV4 {
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     #[must_use]
-    #[rustc_const_unstable(feature = "const_socketaddr", issue = "none")]
+    #[rustc_const_unstable(feature = "const_socketaddr", issue = "82485")]
     pub const fn new(ip: Ipv4Addr, port: u16) -> SocketAddrV4 {
         SocketAddrV4 { ip, port }
     }
@@ -369,7 +369,7 @@ impl SocketAddrV6 {
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     #[must_use]
-    #[rustc_const_unstable(feature = "const_socketaddr", issue = "none")]
+    #[rustc_const_unstable(feature = "const_socketaddr", issue = "82485")]
     pub const fn new(ip: Ipv6Addr, port: u16, flowinfo: u32, scope_id: u32) -> SocketAddrV6 {
         SocketAddrV6 { ip, port, flowinfo, scope_id }
     }

From 7aabd85faa9e78e40161839b14946c5aa6750086 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Linus=20F=C3=A4rnstrand?= <faern@faern.net>
Date: Thu, 23 Jun 2022 22:45:40 +0200
Subject: [PATCH 6/8] Remove invalid doc comment on the size of an IP struct

---
 library/std/src/net/ip.rs | 9 ---------
 1 file changed, 9 deletions(-)

diff --git a/library/std/src/net/ip.rs b/library/std/src/net/ip.rs
index 1d49024f13e15..41ca9ba842588 100644
--- a/library/std/src/net/ip.rs
+++ b/library/std/src/net/ip.rs
@@ -14,9 +14,6 @@ use crate::sys_common::{FromInner, IntoInner};
 /// This enum can contain either an [`Ipv4Addr`] or an [`Ipv6Addr`], see their
 /// respective documentation for more details.
 ///
-/// The size of an `IpAddr` instance may vary depending on the target operating
-/// system.
-///
 /// # Examples
 ///
 /// ```
@@ -49,9 +46,6 @@ pub enum IpAddr {
 ///
 /// See [`IpAddr`] for a type encompassing both IPv4 and IPv6 addresses.
 ///
-/// The size of an `Ipv4Addr` struct may vary depending on the target operating
-/// system.
-///
 /// [IETF RFC 791]: https://tools.ietf.org/html/rfc791
 ///
 /// # Textual representation
@@ -87,9 +81,6 @@ pub struct Ipv4Addr {
 /// IPv6 addresses are defined as 128-bit integers in [IETF RFC 4291].
 /// They are usually represented as eight 16-bit segments.
 ///
-/// The size of an `Ipv6Addr` struct may vary depending on the target operating
-/// system.
-///
 /// [IETF RFC 4291]: https://tools.ietf.org/html/rfc4291
 ///
 /// # Embedding IPv4 Addresses

From b20b69a79b4e8bfc3574c767ec798d356d33045d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Linus=20F=C3=A4rnstrand?= <faern@faern.net>
Date: Sun, 17 Jul 2022 09:48:56 +0200
Subject: [PATCH 7/8] Move SocketAddrCRepr to sys_common

---
 library/std/src/net/addr.rs       | 31 ---------------------------
 library/std/src/sys_common/net.rs | 35 +++++++++++++++++++++++++++++++
 2 files changed, 35 insertions(+), 31 deletions(-)

diff --git a/library/std/src/net/addr.rs b/library/std/src/net/addr.rs
index 13d85f2303502..53fee952a7a7a 100644
--- a/library/std/src/net/addr.rs
+++ b/library/std/src/net/addr.rs
@@ -596,37 +596,6 @@ impl<I: Into<IpAddr>> From<(I, u16)> for SocketAddr {
     }
 }
 
-/// A type with the same memory layout as `c::sockaddr`. Used in converting Rust level
-/// SocketAddr* types into their system representation. The benefit of this specific
-/// type over using `c::sockaddr_storage` is that this type is exactly as large as it
-/// needs to be and not a lot larger. And it can be initialized more cleanly from Rust.
-#[repr(C)]
-pub(crate) union SocketAddrCRepr {
-    v4: c::sockaddr_in,
-    v6: c::sockaddr_in6,
-}
-
-impl SocketAddrCRepr {
-    pub fn as_ptr(&self) -> *const c::sockaddr {
-        self as *const _ as *const c::sockaddr
-    }
-}
-
-impl<'a> IntoInner<(SocketAddrCRepr, c::socklen_t)> for &'a SocketAddr {
-    fn into_inner(self) -> (SocketAddrCRepr, c::socklen_t) {
-        match *self {
-            SocketAddr::V4(ref a) => {
-                let sockaddr = SocketAddrCRepr { v4: a.into_inner() };
-                (sockaddr, mem::size_of::<c::sockaddr_in>() as c::socklen_t)
-            }
-            SocketAddr::V6(ref a) => {
-                let sockaddr = SocketAddrCRepr { v6: a.into_inner() };
-                (sockaddr, mem::size_of::<c::sockaddr_in6>() as c::socklen_t)
-            }
-        }
-    }
-}
-
 #[stable(feature = "rust1", since = "1.0.0")]
 impl fmt::Display for SocketAddr {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
diff --git a/library/std/src/sys_common/net.rs b/library/std/src/sys_common/net.rs
index e49337999d2c5..47c6a82f6469b 100644
--- a/library/std/src/sys_common/net.rs
+++ b/library/std/src/sys_common/net.rs
@@ -700,3 +700,38 @@ impl fmt::Debug for UdpSocket {
         res.field(name, &self.inner.as_raw()).finish()
     }
 }
+
+////////////////////////////////////////////////////////////////////////////////
+// Converting SocketAddr to libc representation
+////////////////////////////////////////////////////////////////////////////////
+
+/// A type with the same memory layout as `c::sockaddr`. Used in converting Rust level
+/// SocketAddr* types into their system representation. The benefit of this specific
+/// type over using `c::sockaddr_storage` is that this type is exactly as large as it
+/// needs to be and not a lot larger. And it can be initialized more cleanly from Rust.
+#[repr(C)]
+pub(crate) union SocketAddrCRepr {
+    v4: c::sockaddr_in,
+    v6: c::sockaddr_in6,
+}
+
+impl SocketAddrCRepr {
+    pub fn as_ptr(&self) -> *const c::sockaddr {
+        self as *const _ as *const c::sockaddr
+    }
+}
+
+impl<'a> IntoInner<(SocketAddrCRepr, c::socklen_t)> for &'a SocketAddr {
+    fn into_inner(self) -> (SocketAddrCRepr, c::socklen_t) {
+        match *self {
+            SocketAddr::V4(ref a) => {
+                let sockaddr = SocketAddrCRepr { v4: a.into_inner() };
+                (sockaddr, mem::size_of::<c::sockaddr_in>() as c::socklen_t)
+            }
+            SocketAddr::V6(ref a) => {
+                let sockaddr = SocketAddrCRepr { v6: a.into_inner() };
+                (sockaddr, mem::size_of::<c::sockaddr_in6>() as c::socklen_t)
+            }
+        }
+    }
+}

From 73bb371ad3dd401a8f6dca518ad2bbf0bad590e5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Linus=20F=C3=A4rnstrand?= <faern@faern.net>
Date: Sun, 24 Jul 2022 18:27:19 +0200
Subject: [PATCH 8/8] Remove socklen_t from platforms where it's no longer used

---
 library/std/src/sys/sgx/net.rs         | 2 --
 library/std/src/sys/unsupported/net.rs | 2 --
 library/std/src/sys/wasi/net.rs        | 2 --
 3 files changed, 6 deletions(-)

diff --git a/library/std/src/sys/sgx/net.rs b/library/std/src/sys/sgx/net.rs
index 1d899525081b9..4c4cd7d1d1d86 100644
--- a/library/std/src/sys/sgx/net.rs
+++ b/library/std/src/sys/sgx/net.rs
@@ -538,6 +538,4 @@ pub mod netc {
 
     #[derive(Copy, Clone)]
     pub struct sockaddr {}
-
-    pub type socklen_t = usize;
 }
diff --git a/library/std/src/sys/unsupported/net.rs b/library/std/src/sys/unsupported/net.rs
index 360115d503374..a5204a0845378 100644
--- a/library/std/src/sys/unsupported/net.rs
+++ b/library/std/src/sys/unsupported/net.rs
@@ -363,6 +363,4 @@ pub mod netc {
 
     #[derive(Copy, Clone)]
     pub struct sockaddr {}
-
-    pub type socklen_t = usize;
 }
diff --git a/library/std/src/sys/wasi/net.rs b/library/std/src/sys/wasi/net.rs
index 937b1b850e7ba..590d268c38087 100644
--- a/library/std/src/sys/wasi/net.rs
+++ b/library/std/src/sys/wasi/net.rs
@@ -524,6 +524,4 @@ pub mod netc {
 
     #[derive(Copy, Clone)]
     pub struct sockaddr {}
-
-    pub type socklen_t = usize;
 }