Merge remote-tracking branch 'origin/master' into mpk/add-long-error-message-for-E0311

1 files changed, 974 insertions, 0 deletions

diff --git a/library/std/src/net/socket_addr.rs b/library/std/src/net/socket_addr.rs
new file mode 100644
index 00000000000..33b0dfa03e0
--- /dev/null
+++ b/library/std/src/net/socket_addr.rs
@@ -0,0 +1,974 @@
+#[cfg(all(test, not(target_os = "emscripten")))]
+mod tests;
+
+use crate::cmp::Ordering;
+use crate::fmt::{self, Write};
+use crate::hash;
+use crate::io;
+use crate::iter;
+use crate::mem;
+use crate::net::{IpAddr, Ipv4Addr, Ipv6Addr};
+use crate::option;
+use crate::slice;
+use crate::sys::net::netc as c;
+use crate::sys_common::net::LookupHost;
+use crate::sys_common::{FromInner, IntoInner};
+use crate::vec;
+
+use super::display_buffer::DisplayBuffer;
+
+/// An internet socket address, either IPv4 or IPv6.
+///
+/// Internet socket addresses consist of an [IP address], a 16-bit port number, as well
+/// as possibly some version-dependent additional information. See [`SocketAddrV4`]'s and
+/// [`SocketAddrV6`]'s respective documentation for more details.
+///
+/// The size of a `SocketAddr` instance may vary depending on the target operating
+/// system.
+///
+/// [IP address]: IpAddr
+///
+/// # Examples
+///
+/// ```
+/// use std::net::{IpAddr, Ipv4Addr, SocketAddr};
+///
+/// let socket = SocketAddr::new(IpAddr::V4(Ipv4Addr::new(127, 0, 0, 1)), 8080);
+///
+/// assert_eq!("127.0.0.1:8080".parse(), Ok(socket));
+/// assert_eq!(socket.port(), 8080);
+/// assert_eq!(socket.is_ipv4(), true);
+/// ```
+#[derive(Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub enum SocketAddr {
+    /// An IPv4 socket address.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    V4(#[stable(feature = "rust1", since = "1.0.0")] SocketAddrV4),
+    /// An IPv6 socket address.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    V6(#[stable(feature = "rust1", since = "1.0.0")] SocketAddrV6),
+}
+
+/// An IPv4 socket address.
+///
+/// IPv4 socket addresses consist of an [`IPv4` address] and a 16-bit port number, as
+/// stated in [IETF RFC 793].
+///
+/// See [`SocketAddr`] for a type encompassing both IPv4 and IPv6 socket addresses.
+///
+/// The size of a `SocketAddrV4` struct may vary depending on the target operating
+/// system. Do not assume that this type has the same memory layout as the underlying
+/// system representation.
+///
+/// [IETF RFC 793]: https://tools.ietf.org/html/rfc793
+/// [`IPv4` address]: Ipv4Addr
+///
+/// # Examples
+///
+/// ```
+/// use std::net::{Ipv4Addr, SocketAddrV4};
+///
+/// let socket = SocketAddrV4::new(Ipv4Addr::new(127, 0, 0, 1), 8080);
+///
+/// assert_eq!("127.0.0.1:8080".parse(), Ok(socket));
+/// assert_eq!(socket.ip(), &Ipv4Addr::new(127, 0, 0, 1));
+/// assert_eq!(socket.port(), 8080);
+/// ```
+#[derive(Copy, Clone, Eq, PartialEq)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct SocketAddrV4 {
+    ip: Ipv4Addr,
+    port: u16,
+}
+
+/// An IPv6 socket address.
+///
+/// IPv6 socket addresses consist of an [`IPv6` address], a 16-bit port number, as well
+/// as fields containing the traffic class, the flow label, and a scope identifier
+/// (see [IETF RFC 2553, Section 3.3] for more details).
+///
+/// See [`SocketAddr`] for a type encompassing both IPv4 and IPv6 socket addresses.
+///
+/// The size of a `SocketAddrV6` struct may vary depending on the target operating
+/// system. Do not assume that this type has the same memory layout as the underlying
+/// system representation.
+///
+/// [IETF RFC 2553, Section 3.3]: https://tools.ietf.org/html/rfc2553#section-3.3
+/// [`IPv6` address]: Ipv6Addr
+///
+/// # Examples
+///
+/// ```
+/// use std::net::{Ipv6Addr, SocketAddrV6};
+///
+/// let socket = SocketAddrV6::new(Ipv6Addr::new(0x2001, 0xdb8, 0, 0, 0, 0, 0, 1), 8080, 0, 0);
+///
+/// assert_eq!("[2001:db8::1]:8080".parse(), Ok(socket));
+/// assert_eq!(socket.ip(), &Ipv6Addr::new(0x2001, 0xdb8, 0, 0, 0, 0, 0, 1));
+/// assert_eq!(socket.port(), 8080);
+/// ```
+#[derive(Copy, Clone, Eq, PartialEq)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct SocketAddrV6 {
+    ip: Ipv6Addr,
+    port: u16,
+    flowinfo: u32,
+    scope_id: u32,
+}
+
+impl SocketAddr {
+    /// Creates a new socket address from an [IP address] and a port number.
+    ///
+    /// [IP address]: IpAddr
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::net::{IpAddr, Ipv4Addr, SocketAddr};
+    ///
+    /// let socket = SocketAddr::new(IpAddr::V4(Ipv4Addr::new(127, 0, 0, 1)), 8080);
+    /// assert_eq!(socket.ip(), IpAddr::V4(Ipv4Addr::new(127, 0, 0, 1)));
+    /// assert_eq!(socket.port(), 8080);
+    /// ```
+    #[stable(feature = "ip_addr", since = "1.7.0")]
+    #[must_use]
+    #[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)),
+            IpAddr::V6(a) => SocketAddr::V6(SocketAddrV6::new(a, port, 0, 0)),
+        }
+    }
+
+    /// Returns the IP address associated with this socket address.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::net::{IpAddr, Ipv4Addr, SocketAddr};
+    ///
+    /// let socket = SocketAddr::new(IpAddr::V4(Ipv4Addr::new(127, 0, 0, 1)), 8080);
+    /// assert_eq!(socket.ip(), IpAddr::V4(Ipv4Addr::new(127, 0, 0, 1)));
+    /// ```
+    #[must_use]
+    #[stable(feature = "ip_addr", since = "1.7.0")]
+    #[rustc_const_unstable(feature = "const_socketaddr", issue = "82485")]
+    pub const fn ip(&self) -> IpAddr {
+        match *self {
+            SocketAddr::V4(ref a) => IpAddr::V4(*a.ip()),
+            SocketAddr::V6(ref a) => IpAddr::V6(*a.ip()),
+        }
+    }
+
+    /// Changes the IP address associated with this socket address.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::net::{IpAddr, Ipv4Addr, SocketAddr};
+    ///
+    /// let mut socket = SocketAddr::new(IpAddr::V4(Ipv4Addr::new(127, 0, 0, 1)), 8080);
+    /// socket.set_ip(IpAddr::V4(Ipv4Addr::new(10, 10, 0, 1)));
+    /// assert_eq!(socket.ip(), IpAddr::V4(Ipv4Addr::new(10, 10, 0, 1)));
+    /// ```
+    #[stable(feature = "sockaddr_setters", since = "1.9.0")]
+    pub fn set_ip(&mut self, new_ip: IpAddr) {
+        // `match (*self, new_ip)` would have us mutate a copy of self only to throw it away.
+        match (self, new_ip) {
+            (&mut SocketAddr::V4(ref mut a), IpAddr::V4(new_ip)) => a.set_ip(new_ip),
+            (&mut SocketAddr::V6(ref mut a), IpAddr::V6(new_ip)) => a.set_ip(new_ip),
+            (self_, new_ip) => *self_ = Self::new(new_ip, self_.port()),
+        }
+    }
+
+    /// Returns the port number associated with this socket address.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::net::{IpAddr, Ipv4Addr, SocketAddr};
+    ///
+    /// let socket = SocketAddr::new(IpAddr::V4(Ipv4Addr::new(127, 0, 0, 1)), 8080);
+    /// assert_eq!(socket.port(), 8080);
+    /// ```
+    #[must_use]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_const_unstable(feature = "const_socketaddr", issue = "82485")]
+    pub const fn port(&self) -> u16 {
+        match *self {
+            SocketAddr::V4(ref a) => a.port(),
+            SocketAddr::V6(ref a) => a.port(),
+        }
+    }
+
+    /// Changes the port number associated with this socket address.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::net::{IpAddr, Ipv4Addr, SocketAddr};
+    ///
+    /// let mut socket = SocketAddr::new(IpAddr::V4(Ipv4Addr::new(127, 0, 0, 1)), 8080);
+    /// socket.set_port(1025);
+    /// assert_eq!(socket.port(), 1025);
+    /// ```
+    #[stable(feature = "sockaddr_setters", since = "1.9.0")]
+    pub fn set_port(&mut self, new_port: u16) {
+        match *self {
+            SocketAddr::V4(ref mut a) => a.set_port(new_port),
+            SocketAddr::V6(ref mut a) => a.set_port(new_port),
+        }
+    }
+
+    /// Returns [`true`] if the [IP address] in this `SocketAddr` is an
+    /// [`IPv4` address], and [`false`] otherwise.
+    ///
+    /// [IP address]: IpAddr
+    /// [`IPv4` address]: IpAddr::V4
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::net::{IpAddr, Ipv4Addr, SocketAddr};
+    ///
+    /// let socket = SocketAddr::new(IpAddr::V4(Ipv4Addr::new(127, 0, 0, 1)), 8080);
+    /// assert_eq!(socket.is_ipv4(), true);
+    /// assert_eq!(socket.is_ipv6(), false);
+    /// ```
+    #[must_use]
+    #[stable(feature = "sockaddr_checker", since = "1.16.0")]
+    #[rustc_const_unstable(feature = "const_socketaddr", issue = "82485")]
+    pub const fn is_ipv4(&self) -> bool {
+        matches!(*self, SocketAddr::V4(_))
+    }
+
+    /// Returns [`true`] if the [IP address] in this `SocketAddr` is an
+    /// [`IPv6` address], and [`false`] otherwise.
+    ///
+    /// [IP address]: IpAddr
+    /// [`IPv6` address]: IpAddr::V6
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::net::{IpAddr, Ipv6Addr, SocketAddr};
+    ///
+    /// let socket = SocketAddr::new(IpAddr::V6(Ipv6Addr::new(0, 0, 0, 0, 0, 65535, 0, 1)), 8080);
+    /// assert_eq!(socket.is_ipv4(), false);
+    /// assert_eq!(socket.is_ipv6(), true);
+    /// ```
+    #[must_use]
+    #[stable(feature = "sockaddr_checker", since = "1.16.0")]
+    #[rustc_const_unstable(feature = "const_socketaddr", issue = "82485")]
+    pub const fn is_ipv6(&self) -> bool {
+        matches!(*self, SocketAddr::V6(_))
+    }
+}
+
+impl SocketAddrV4 {
+    /// Creates a new socket address from an [`IPv4` address] and a port number.
+    ///
+    /// [`IPv4` address]: Ipv4Addr
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::net::{SocketAddrV4, Ipv4Addr};
+    ///
+    /// let socket = SocketAddrV4::new(Ipv4Addr::new(127, 0, 0, 1), 8080);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[must_use]
+    #[rustc_const_unstable(feature = "const_socketaddr", issue = "82485")]
+    pub const fn new(ip: Ipv4Addr, port: u16) -> SocketAddrV4 {
+        SocketAddrV4 { ip, port }
+    }
+
+    /// Returns the IP address associated with this socket address.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::net::{SocketAddrV4, Ipv4Addr};
+    ///
+    /// let socket = SocketAddrV4::new(Ipv4Addr::new(127, 0, 0, 1), 8080);
+    /// assert_eq!(socket.ip(), &Ipv4Addr::new(127, 0, 0, 1));
+    /// ```
+    #[must_use]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_const_unstable(feature = "const_socketaddr", issue = "82485")]
+    pub const fn ip(&self) -> &Ipv4Addr {
+        &self.ip
+    }
+
+    /// Changes the IP address associated with this socket address.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::net::{SocketAddrV4, Ipv4Addr};
+    ///
+    /// let mut socket = SocketAddrV4::new(Ipv4Addr::new(127, 0, 0, 1), 8080);
+    /// socket.set_ip(Ipv4Addr::new(192, 168, 0, 1));
+    /// assert_eq!(socket.ip(), &Ipv4Addr::new(192, 168, 0, 1));
+    /// ```
+    #[stable(feature = "sockaddr_setters", since = "1.9.0")]
+    pub fn set_ip(&mut self, new_ip: Ipv4Addr) {
+        self.ip = new_ip;
+    }
+
+    /// Returns the port number associated with this socket address.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::net::{SocketAddrV4, Ipv4Addr};
+    ///
+    /// let socket = SocketAddrV4::new(Ipv4Addr::new(127, 0, 0, 1), 8080);
+    /// assert_eq!(socket.port(), 8080);
+    /// ```
+    #[must_use]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_const_unstable(feature = "const_socketaddr", issue = "82485")]
+    pub const fn port(&self) -> u16 {
+        self.port
+    }
+
+    /// Changes the port number associated with this socket address.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::net::{SocketAddrV4, Ipv4Addr};
+    ///
+    /// let mut socket = SocketAddrV4::new(Ipv4Addr::new(127, 0, 0, 1), 8080);
+    /// socket.set_port(4242);
+    /// assert_eq!(socket.port(), 4242);
+    /// ```
+    #[stable(feature = "sockaddr_setters", since = "1.9.0")]
+    pub fn set_port(&mut self, new_port: u16) {
+        self.port = new_port;
+    }
+}
+
+impl SocketAddrV6 {
+    /// Creates a new socket address from an [`IPv6` address], a 16-bit port number,
+    /// and the `flowinfo` and `scope_id` fields.
+    ///
+    /// For more information on the meaning and layout of the `flowinfo` and `scope_id`
+    /// parameters, see [IETF RFC 2553, Section 3.3].
+    ///
+    /// [IETF RFC 2553, Section 3.3]: https://tools.ietf.org/html/rfc2553#section-3.3
+    /// [`IPv6` address]: Ipv6Addr
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::net::{SocketAddrV6, Ipv6Addr};
+    ///
+    /// let socket = SocketAddrV6::new(Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 1), 8080, 0, 0);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[must_use]
+    #[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 }
+    }
+
+    /// Returns the IP address associated with this socket address.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::net::{SocketAddrV6, Ipv6Addr};
+    ///
+    /// let socket = SocketAddrV6::new(Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 1), 8080, 0, 0);
+    /// assert_eq!(socket.ip(), &Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 1));
+    /// ```
+    #[must_use]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_const_unstable(feature = "const_socketaddr", issue = "82485")]
+    pub const fn ip(&self) -> &Ipv6Addr {
+        &self.ip
+    }
+
+    /// Changes the IP address associated with this socket address.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::net::{SocketAddrV6, Ipv6Addr};
+    ///
+    /// let mut socket = SocketAddrV6::new(Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 1), 8080, 0, 0);
+    /// socket.set_ip(Ipv6Addr::new(76, 45, 0, 0, 0, 0, 0, 0));
+    /// assert_eq!(socket.ip(), &Ipv6Addr::new(76, 45, 0, 0, 0, 0, 0, 0));
+    /// ```
+    #[stable(feature = "sockaddr_setters", since = "1.9.0")]
+    pub fn set_ip(&mut self, new_ip: Ipv6Addr) {
+        self.ip = new_ip;
+    }
+
+    /// Returns the port number associated with this socket address.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::net::{SocketAddrV6, Ipv6Addr};
+    ///
+    /// let socket = SocketAddrV6::new(Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 1), 8080, 0, 0);
+    /// assert_eq!(socket.port(), 8080);
+    /// ```
+    #[must_use]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_const_unstable(feature = "const_socketaddr", issue = "82485")]
+    pub const fn port(&self) -> u16 {
+        self.port
+    }
+
+    /// Changes the port number associated with this socket address.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::net::{SocketAddrV6, Ipv6Addr};
+    ///
+    /// let mut socket = SocketAddrV6::new(Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 1), 8080, 0, 0);
+    /// socket.set_port(4242);
+    /// assert_eq!(socket.port(), 4242);
+    /// ```
+    #[stable(feature = "sockaddr_setters", since = "1.9.0")]
+    pub fn set_port(&mut self, new_port: u16) {
+        self.port = new_port;
+    }
+
+    /// Returns the flow information associated with this address.
+    ///
+    /// This information corresponds to the `sin6_flowinfo` field in C's `netinet/in.h`,
+    /// as specified in [IETF RFC 2553, Section 3.3].
+    /// It combines information about the flow label and the traffic class as specified
+    /// in [IETF RFC 2460], respectively [Section 6] and [Section 7].
+    ///
+    /// [IETF RFC 2553, Section 3.3]: https://tools.ietf.org/html/rfc2553#section-3.3
+    /// [IETF RFC 2460]: https://tools.ietf.org/html/rfc2460
+    /// [Section 6]: https://tools.ietf.org/html/rfc2460#section-6
+    /// [Section 7]: https://tools.ietf.org/html/rfc2460#section-7
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::net::{SocketAddrV6, Ipv6Addr};
+    ///
+    /// let socket = SocketAddrV6::new(Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 1), 8080, 10, 0);
+    /// assert_eq!(socket.flowinfo(), 10);
+    /// ```
+    #[must_use]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_const_unstable(feature = "const_socketaddr", issue = "82485")]
+    pub const fn flowinfo(&self) -> u32 {
+        self.flowinfo
+    }
+
+    /// Changes the flow information associated with this socket address.
+    ///
+    /// See [`SocketAddrV6::flowinfo`]'s documentation for more details.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::net::{SocketAddrV6, Ipv6Addr};
+    ///
+    /// let mut socket = SocketAddrV6::new(Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 1), 8080, 10, 0);
+    /// socket.set_flowinfo(56);
+    /// assert_eq!(socket.flowinfo(), 56);
+    /// ```
+    #[stable(feature = "sockaddr_setters", since = "1.9.0")]
+    pub fn set_flowinfo(&mut self, new_flowinfo: u32) {
+        self.flowinfo = new_flowinfo;
+    }
+
+    /// Returns the scope ID associated with this address.
+    ///
+    /// This information corresponds to the `sin6_scope_id` field in C's `netinet/in.h`,
+    /// as specified in [IETF RFC 2553, Section 3.3].
+    ///
+    /// [IETF RFC 2553, Section 3.3]: https://tools.ietf.org/html/rfc2553#section-3.3
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::net::{SocketAddrV6, Ipv6Addr};
+    ///
+    /// let socket = SocketAddrV6::new(Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 1), 8080, 0, 78);
+    /// assert_eq!(socket.scope_id(), 78);
+    /// ```
+    #[must_use]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_const_unstable(feature = "const_socketaddr", issue = "82485")]
+    pub const fn scope_id(&self) -> u32 {
+        self.scope_id
+    }
+
+    /// Changes the scope ID associated with this socket address.
+    ///
+    /// See [`SocketAddrV6::scope_id`]'s documentation for more details.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::net::{SocketAddrV6, Ipv6Addr};
+    ///
+    /// let mut socket = SocketAddrV6::new(Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 1), 8080, 0, 78);
+    /// socket.set_scope_id(42);
+    /// assert_eq!(socket.scope_id(), 42);
+    /// ```
+    #[stable(feature = "sockaddr_setters", since = "1.9.0")]
+    pub fn set_scope_id(&mut self, new_scope_id: u32) {
+        self.scope_id = new_scope_id;
+    }
+}
+
+impl FromInner<c::sockaddr_in> for SocketAddrV4 {
+    fn from_inner(addr: c::sockaddr_in) -> SocketAddrV4 {
+        SocketAddrV4 { ip: Ipv4Addr::from_inner(addr.sin_addr), port: u16::from_be(addr.sin_port) }
+    }
+}
+
+impl FromInner<c::sockaddr_in6> for SocketAddrV6 {
+    fn from_inner(addr: c::sockaddr_in6) -> SocketAddrV6 {
+        SocketAddrV6 {
+            ip: Ipv6Addr::from_inner(addr.sin6_addr),
+            port: u16::from_be(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: self.port.to_be(),
+            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: self.port.to_be(),
+            sin6_addr: self.ip.into_inner(),
+            sin6_flowinfo: self.flowinfo,
+            sin6_scope_id: self.scope_id,
+            ..unsafe { mem::zeroed() }
+        }
+    }
+}
+
+#[stable(feature = "ip_from_ip", since = "1.16.0")]
+impl From<SocketAddrV4> for SocketAddr {
+    /// Converts a [`SocketAddrV4`] into a [`SocketAddr::V4`].
+    fn from(sock4: SocketAddrV4) -> SocketAddr {
+        SocketAddr::V4(sock4)
+    }
+}
+
+#[stable(feature = "ip_from_ip", since = "1.16.0")]
+impl From<SocketAddrV6> for SocketAddr {
+    /// Converts a [`SocketAddrV6`] into a [`SocketAddr::V6`].
+    fn from(sock6: SocketAddrV6) -> SocketAddr {
+        SocketAddr::V6(sock6)
+    }
+}
+
+#[stable(feature = "addr_from_into_ip", since = "1.17.0")]
+impl<I: Into<IpAddr>> From<(I, u16)> for SocketAddr {
+    /// Converts a tuple struct (Into<[`IpAddr`]>, `u16`) into a [`SocketAddr`].
+    ///
+    /// This conversion creates a [`SocketAddr::V4`] for an [`IpAddr::V4`]
+    /// and creates a [`SocketAddr::V6`] for an [`IpAddr::V6`].
+    ///
+    /// `u16` is treated as port of the newly created [`SocketAddr`].
+    fn from(pieces: (I, u16)) -> SocketAddr {
+        SocketAddr::new(pieces.0.into(), pieces.1)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl fmt::Display for SocketAddr {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match *self {
+            SocketAddr::V4(ref a) => a.fmt(f),
+            SocketAddr::V6(ref a) => a.fmt(f),
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl fmt::Debug for SocketAddr {
+    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fmt::Display::fmt(self, fmt)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl fmt::Display for SocketAddrV4 {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        // If there are no alignment requirements, write the socket address directly to `f`.
+        // Otherwise, write it to a local buffer and then use `f.pad`.
+        if f.precision().is_none() && f.width().is_none() {
+            write!(f, "{}:{}", self.ip(), self.port())
+        } else {
+            const LONGEST_IPV4_SOCKET_ADDR: &str = "255.255.255.255:65536";
+
+            let mut buf = DisplayBuffer::<{ LONGEST_IPV4_SOCKET_ADDR.len() }>::new();
+            // Buffer is long enough for the longest possible IPv4 socket address, so this should never fail.
+            write!(buf, "{}:{}", self.ip(), self.port()).unwrap();
+
+            f.pad(buf.as_str())
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl fmt::Debug for SocketAddrV4 {
+    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fmt::Display::fmt(self, fmt)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl fmt::Display for SocketAddrV6 {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        // If there are no alignment requirements, write the socket address directly to `f`.
+        // Otherwise, write it to a local buffer and then use `f.pad`.
+        if f.precision().is_none() && f.width().is_none() {
+            match self.scope_id() {
+                0 => write!(f, "[{}]:{}", self.ip(), self.port()),
+                scope_id => write!(f, "[{}%{}]:{}", self.ip(), scope_id, self.port()),
+            }
+        } else {
+            const LONGEST_IPV6_SOCKET_ADDR: &str =
+                "[ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff%4294967296]:65536";
+
+            let mut buf = DisplayBuffer::<{ LONGEST_IPV6_SOCKET_ADDR.len() }>::new();
+            match self.scope_id() {
+                0 => write!(buf, "[{}]:{}", self.ip(), self.port()),
+                scope_id => write!(buf, "[{}%{}]:{}", self.ip(), scope_id, self.port()),
+            }
+            // Buffer is long enough for the longest possible IPv6 socket address, so this should never fail.
+            .unwrap();
+
+            f.pad(buf.as_str())
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl fmt::Debug for SocketAddrV6 {
+    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fmt::Display::fmt(self, fmt)
+    }
+}
+
+#[stable(feature = "socketaddr_ordering", since = "1.45.0")]
+impl PartialOrd for SocketAddrV4 {
+    fn partial_cmp(&self, other: &SocketAddrV4) -> Option<Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
+#[stable(feature = "socketaddr_ordering", since = "1.45.0")]
+impl PartialOrd for SocketAddrV6 {
+    fn partial_cmp(&self, other: &SocketAddrV6) -> Option<Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
+#[stable(feature = "socketaddr_ordering", since = "1.45.0")]
+impl Ord for SocketAddrV4 {
+    fn cmp(&self, other: &SocketAddrV4) -> Ordering {
+        self.ip().cmp(other.ip()).then(self.port().cmp(&other.port()))
+    }
+}
+
+#[stable(feature = "socketaddr_ordering", since = "1.45.0")]
+impl Ord for SocketAddrV6 {
+    fn cmp(&self, other: &SocketAddrV6) -> Ordering {
+        self.ip().cmp(other.ip()).then(self.port().cmp(&other.port()))
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl hash::Hash for SocketAddrV4 {
+    fn hash<H: hash::Hasher>(&self, s: &mut H) {
+        (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.port, &self.ip, self.flowinfo, self.scope_id).hash(s)
+    }
+}
+
+/// A trait for objects which can be converted or resolved to one or more
+/// [`SocketAddr`] values.
+///
+/// This trait is used for generic address resolution when constructing network
+/// objects. By default it is implemented for the following types:
+///
+///  * [`SocketAddr`]: [`to_socket_addrs`] is the identity function.
+///
+///  * [`SocketAddrV4`], [`SocketAddrV6`], <code>([IpAddr], [u16])</code>,
+///    <code>([Ipv4Addr], [u16])</code>, <code>([Ipv6Addr], [u16])</code>:
+///    [`to_socket_addrs`] constructs a [`SocketAddr`] trivially.
+///
+///  * <code>(&[str], [u16])</code>: <code>&[str]</code> should be either a string representation
+///    of an [`IpAddr`] address as expected by [`FromStr`] implementation or a host
+///    name. [`u16`] is the port number.
+///
+///  * <code>&[str]</code>: the string should be either a string representation of a
+///    [`SocketAddr`] as expected by its [`FromStr`] implementation or a string like
+///    `<host_name>:<port>` pair where `<port>` is a [`u16`] value.
+///
+/// This trait allows constructing network objects like [`TcpStream`] or
+/// [`UdpSocket`] easily with values of various types for the bind/connection
+/// address. It is needed because sometimes one type is more appropriate than
+/// the other: for simple uses a string like `"localhost:12345"` is much nicer
+/// than manual construction of the corresponding [`SocketAddr`], but sometimes
+/// [`SocketAddr`] value is *the* main source of the address, and converting it to
+/// some other type (e.g., a string) just for it to be converted back to
+/// [`SocketAddr`] in constructor methods is pointless.
+///
+/// Addresses returned by the operating system that are not IP addresses are
+/// silently ignored.
+///
+/// [`FromStr`]: crate::str::FromStr "std::str::FromStr"
+/// [`TcpStream`]: crate::net::TcpStream "net::TcpStream"
+/// [`to_socket_addrs`]: ToSocketAddrs::to_socket_addrs
+/// [`UdpSocket`]: crate::net::UdpSocket "net::UdpSocket"
+///
+/// # Examples
+///
+/// Creating a [`SocketAddr`] iterator that yields one item:
+///
+/// ```
+/// use std::net::{ToSocketAddrs, SocketAddr};
+///
+/// let addr = SocketAddr::from(([127, 0, 0, 1], 443));
+/// let mut addrs_iter = addr.to_socket_addrs().unwrap();
+///
+/// assert_eq!(Some(addr), addrs_iter.next());
+/// assert!(addrs_iter.next().is_none());
+/// ```
+///
+/// Creating a [`SocketAddr`] iterator from a hostname:
+///
+/// ```no_run
+/// use std::net::{SocketAddr, ToSocketAddrs};
+///
+/// // assuming 'localhost' resolves to 127.0.0.1
+/// let mut addrs_iter = "localhost:443".to_socket_addrs().unwrap();
+/// assert_eq!(addrs_iter.next(), Some(SocketAddr::from(([127, 0, 0, 1], 443))));
+/// assert!(addrs_iter.next().is_none());
+///
+/// // assuming 'foo' does not resolve
+/// assert!("foo:443".to_socket_addrs().is_err());
+/// ```
+///
+/// Creating a [`SocketAddr`] iterator that yields multiple items:
+///
+/// ```
+/// use std::net::{SocketAddr, ToSocketAddrs};
+///
+/// let addr1 = SocketAddr::from(([0, 0, 0, 0], 80));
+/// let addr2 = SocketAddr::from(([127, 0, 0, 1], 443));
+/// let addrs = vec![addr1, addr2];
+///
+/// let mut addrs_iter = (&addrs[..]).to_socket_addrs().unwrap();
+///
+/// assert_eq!(Some(addr1), addrs_iter.next());
+/// assert_eq!(Some(addr2), addrs_iter.next());
+/// assert!(addrs_iter.next().is_none());
+/// ```
+///
+/// Attempting to create a [`SocketAddr`] iterator from an improperly formatted
+/// socket address `&str` (missing the port):
+///
+/// ```
+/// use std::io;
+/// use std::net::ToSocketAddrs;
+///
+/// let err = "127.0.0.1".to_socket_addrs().unwrap_err();
+/// assert_eq!(err.kind(), io::ErrorKind::InvalidInput);
+/// ```
+///
+/// [`TcpStream::connect`] is an example of an function that utilizes
+/// `ToSocketAddrs` as a trait bound on its parameter in order to accept
+/// different types:
+///
+/// ```no_run
+/// use std::net::{TcpStream, Ipv4Addr};
+///
+/// let stream = TcpStream::connect(("127.0.0.1", 443));
+/// // or
+/// let stream = TcpStream::connect("127.0.0.1:443");
+/// // or
+/// let stream = TcpStream::connect((Ipv4Addr::new(127, 0, 0, 1), 443));
+/// ```
+///
+/// [`TcpStream::connect`]: crate::net::TcpStream::connect
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait ToSocketAddrs {
+    /// Returned iterator over socket addresses which this type may correspond
+    /// to.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    type Iter: Iterator<Item = SocketAddr>;
+
+    /// Converts this object to an iterator of resolved [`SocketAddr`]s.
+    ///
+    /// The returned iterator might not actually yield any values depending on the
+    /// outcome of any resolution performed.
+    ///
+    /// Note that this function may block the current thread while resolution is
+    /// performed.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn to_socket_addrs(&self) -> io::Result<Self::Iter>;
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl ToSocketAddrs for SocketAddr {
+    type Iter = option::IntoIter<SocketAddr>;
+    fn to_socket_addrs(&self) -> io::Result<option::IntoIter<SocketAddr>> {
+        Ok(Some(*self).into_iter())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl ToSocketAddrs for SocketAddrV4 {
+    type Iter = option::IntoIter<SocketAddr>;
+    fn to_socket_addrs(&self) -> io::Result<option::IntoIter<SocketAddr>> {
+        SocketAddr::V4(*self).to_socket_addrs()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl ToSocketAddrs for SocketAddrV6 {
+    type Iter = option::IntoIter<SocketAddr>;
+    fn to_socket_addrs(&self) -> io::Result<option::IntoIter<SocketAddr>> {
+        SocketAddr::V6(*self).to_socket_addrs()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl ToSocketAddrs for (IpAddr, u16) {
+    type Iter = option::IntoIter<SocketAddr>;
+    fn to_socket_addrs(&self) -> io::Result<option::IntoIter<SocketAddr>> {
+        let (ip, port) = *self;
+        match ip {
+            IpAddr::V4(ref a) => (*a, port).to_socket_addrs(),
+            IpAddr::V6(ref a) => (*a, port).to_socket_addrs(),
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl ToSocketAddrs for (Ipv4Addr, u16) {
+    type Iter = option::IntoIter<SocketAddr>;
+    fn to_socket_addrs(&self) -> io::Result<option::IntoIter<SocketAddr>> {
+        let (ip, port) = *self;
+        SocketAddrV4::new(ip, port).to_socket_addrs()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl ToSocketAddrs for (Ipv6Addr, u16) {
+    type Iter = option::IntoIter<SocketAddr>;
+    fn to_socket_addrs(&self) -> io::Result<option::IntoIter<SocketAddr>> {
+        let (ip, port) = *self;
+        SocketAddrV6::new(ip, port, 0, 0).to_socket_addrs()
+    }
+}
+
+fn resolve_socket_addr(lh: LookupHost) -> io::Result<vec::IntoIter<SocketAddr>> {
+    let p = lh.port();
+    let v: Vec<_> = lh
+        .map(|mut a| {
+            a.set_port(p);
+            a
+        })
+        .collect();
+    Ok(v.into_iter())
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl ToSocketAddrs for (&str, u16) {
+    type Iter = vec::IntoIter<SocketAddr>;
+    fn to_socket_addrs(&self) -> io::Result<vec::IntoIter<SocketAddr>> {
+        let (host, port) = *self;
+
+        // try to parse the host as a regular IP address first
+        if let Ok(addr) = host.parse::<Ipv4Addr>() {
+            let addr = SocketAddrV4::new(addr, port);
+            return Ok(vec![SocketAddr::V4(addr)].into_iter());
+        }
+        if let Ok(addr) = host.parse::<Ipv6Addr>() {
+            let addr = SocketAddrV6::new(addr, port, 0, 0);
+            return Ok(vec![SocketAddr::V6(addr)].into_iter());
+        }
+
+        resolve_socket_addr((host, port).try_into()?)
+    }
+}
+
+#[stable(feature = "string_u16_to_socket_addrs", since = "1.46.0")]
+impl ToSocketAddrs for (String, u16) {
+    type Iter = vec::IntoIter<SocketAddr>;
+    fn to_socket_addrs(&self) -> io::Result<vec::IntoIter<SocketAddr>> {
+        (&*self.0, self.1).to_socket_addrs()
+    }
+}
+
+// accepts strings like 'localhost:12345'
+#[stable(feature = "rust1", since = "1.0.0")]
+impl ToSocketAddrs for str {
+    type Iter = vec::IntoIter<SocketAddr>;
+    fn to_socket_addrs(&self) -> io::Result<vec::IntoIter<SocketAddr>> {
+        // try to parse as a regular SocketAddr first
+        if let Ok(addr) = self.parse() {
+            return Ok(vec![addr].into_iter());
+        }
+
+        resolve_socket_addr(self.try_into()?)
+    }
+}
+
+#[stable(feature = "slice_to_socket_addrs", since = "1.8.0")]
+impl<'a> ToSocketAddrs for &'a [SocketAddr] {
+    type Iter = iter::Cloned<slice::Iter<'a, SocketAddr>>;
+
+    fn to_socket_addrs(&self) -> io::Result<Self::Iter> {
+        Ok(self.iter().cloned())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: ToSocketAddrs + ?Sized> ToSocketAddrs for &T {
+    type Iter = T::Iter;
+    fn to_socket_addrs(&self) -> io::Result<T::Iter> {
+        (**self).to_socket_addrs()
+    }
+}
+
+#[stable(feature = "string_to_socket_addrs", since = "1.16.0")]
+impl ToSocketAddrs for String {
+    type Iter = vec::IntoIter<SocketAddr>;
+    fn to_socket_addrs(&self) -> io::Result<vec::IntoIter<SocketAddr>> {
+        (&**self).to_socket_addrs()
+    }
+}