library/std/src/net/mod.rs

   1 //! Networking primitives for TCP/UDP communication.
   2 //!
   3 //! This module provides networking functionality for the Transmission Control and User
   4 //! Datagram Protocols, as well as types for IP and socket addresses.
   5 //!
   6 //! # Organization
   7 //!
   8 //! * [`TcpListener`] and [`TcpStream`] provide functionality for communication over TCP
   9 //! * [`UdpSocket`] provides functionality for communication over UDP
  10 //! * [`IpAddr`] represents IP addresses of either IPv4 or IPv6; [`Ipv4Addr`] and
  11 //!   [`Ipv6Addr`] are respectively IPv4 and IPv6 addresses
  12 //! * [`SocketAddr`] represents socket addresses of either IPv4 or IPv6; [`SocketAddrV4`]
  13 //!   and [`SocketAddrV6`] are respectively IPv4 and IPv6 socket addresses
  14 //! * [`ToSocketAddrs`] is a trait that used for generic address resolution when interacting
  15 //!   with networking objects like [`TcpListener`], [`TcpStream`] or [`UdpSocket`]
  16 //! * Other types are return or parameter types for various methods in this module
  17 //!
  18 //! Rust disables inheritance of socket objects to child processes by default when possible.  For
  19 //! example, through the use of the `CLOEXEC` flag in UNIX systems or the `HANDLE_FLAG_INHERIT`
  20 //! flag on Windows.
  21
  22 #![stable(feature = "rust1", since = "1.0.0")]
  23
  24 use crate::io::{self, ErrorKind};
  25
  26 #[stable(feature = "rust1", since = "1.0.0")]
  27 pub use self::addr::{SocketAddr, SocketAddrV4, SocketAddrV6, ToSocketAddrs};
  28 #[stable(feature = "rust1", since = "1.0.0")]
  29 pub use self::ip::{IpAddr, Ipv4Addr, Ipv6Addr, Ipv6MulticastScope};
  30 #[stable(feature = "rust1", since = "1.0.0")]
  31 pub use self::parser::AddrParseError;
  32 #[unstable(feature = "tcplistener_into_incoming", issue = "88339")]
  33 pub use self::tcp::IntoIncoming;
  34 #[stable(feature = "rust1", since = "1.0.0")]
  35 pub use self::tcp::{Incoming, TcpListener, TcpStream};
  36 #[stable(feature = "rust1", since = "1.0.0")]
  37 pub use self::udp::UdpSocket;
  38
  39 mod addr;
  40 mod ip;
  41 mod parser;
  42 mod tcp;
  43 #[cfg(test)]
  44 mod test;
  45 mod udp;
  46
  47 /// Possible values which can be passed to the [`TcpStream::shutdown`] method.
  48 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
  49 #[stable(feature = "rust1", since = "1.0.0")]
  50 pub enum Shutdown {
  51     /// The reading portion of the [`TcpStream`] should be shut down.
  52     ///
  53     /// All currently blocked and future [reads] will return <code>[Ok]\(0)</code>.
  54     ///
  55     /// [reads]: crate::io::Read "io::Read"
  56     #[stable(feature = "rust1", since = "1.0.0")]
  57     Read,
  58     /// The writing portion of the [`TcpStream`] should be shut down.
  59     ///
  60     /// All currently blocked and future [writes] will return an error.
  61     ///
  62     /// [writes]: crate::io::Write "io::Write"
  63     #[stable(feature = "rust1", since = "1.0.0")]
  64     Write,
  65     /// Both the reading and the writing portions of the [`TcpStream`] should be shut down.
  66     ///
  67     /// See [`Shutdown::Read`] and [`Shutdown::Write`] for more information.
  68     #[stable(feature = "rust1", since = "1.0.0")]
  69     Both,
  70 }
  71
  72 #[inline]
  73 const fn htons(i: u16) -> u16 {
  74     i.to_be()
  75 }
  76 #[inline]
  77 const fn ntohs(i: u16) -> u16 {
  78     u16::from_be(i)
  79 }
  80
  81 fn each_addr<A: ToSocketAddrs, F, T>(addr: A, mut f: F) -> io::Result<T>
  82 where
  83     F: FnMut(io::Result<&SocketAddr>) -> io::Result<T>,
  84 {
  85     let addrs = match addr.to_socket_addrs() {
  86         Ok(addrs) => addrs,
  87         Err(e) => return f(Err(e)),
  88     };
  89     let mut last_err = None;
  90     for addr in addrs {
  91         match f(Ok(&addr)) {
  92             Ok(l) => return Ok(l),
  93             Err(e) => last_err = Some(e),
  94         }
  95     }
  96     Err(last_err.unwrap_or_else(|| {
  97         io::const_io_error!(ErrorKind::InvalidInput, "could not resolve to any addresses")
  98     }))
  99 }