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 #![stable(feature = "rust1", since = "1.0.0")]
  19
  20 use crate::io::{self, Error, ErrorKind};
  21
  22 #[stable(feature = "rust1", since = "1.0.0")]
  23 pub use self::addr::{SocketAddr, SocketAddrV4, SocketAddrV6, ToSocketAddrs};
  24 #[stable(feature = "rust1", since = "1.0.0")]
  25 pub use self::ip::{IpAddr, Ipv4Addr, Ipv6Addr, Ipv6MulticastScope};
  26 #[stable(feature = "rust1", since = "1.0.0")]
  27 pub use self::parser::AddrParseError;
  28 #[stable(feature = "rust1", since = "1.0.0")]
  29 pub use self::tcp::{Incoming, TcpListener, TcpStream};
  30 #[stable(feature = "rust1", since = "1.0.0")]
  31 pub use self::udp::UdpSocket;
  32
  33 mod addr;
  34 mod ip;
  35 mod parser;
  36 mod tcp;
  37 #[cfg(test)]
  38 mod test;
  39 mod udp;
  40
  41 /// Possible values which can be passed to the [`TcpStream::shutdown`] method.
  42 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
  43 #[stable(feature = "rust1", since = "1.0.0")]
  44 pub enum Shutdown {
  45     /// The reading portion of the [`TcpStream`] should be shut down.
  46     ///
  47     /// All currently blocked and future [reads] will return [`Ok`]`(0)`.
  48     ///
  49     /// [reads]: crate::io::Read
  50     #[stable(feature = "rust1", since = "1.0.0")]
  51     Read,
  52     /// The writing portion of the [`TcpStream`] should be shut down.
  53     ///
  54     /// All currently blocked and future [writes] will return an error.
  55     ///
  56     /// [writes]: crate::io::Write
  57     #[stable(feature = "rust1", since = "1.0.0")]
  58     Write,
  59     /// Both the reading and the writing portions of the [`TcpStream`] should be shut down.
  60     ///
  61     /// See [`Shutdown::Read`] and [`Shutdown::Write`] for more information.
  62     #[stable(feature = "rust1", since = "1.0.0")]
  63     Both,
  64 }
  65
  66 #[inline]
  67 const fn htons(i: u16) -> u16 {
  68     i.to_be()
  69 }
  70 #[inline]
  71 const fn ntohs(i: u16) -> u16 {
  72     u16::from_be(i)
  73 }
  74
  75 fn each_addr<A: ToSocketAddrs, F, T>(addr: A, mut f: F) -> io::Result<T>
  76 where
  77     F: FnMut(io::Result<&SocketAddr>) -> io::Result<T>,
  78 {
  79     let addrs = match addr.to_socket_addrs() {
  80         Ok(addrs) => addrs,
  81         Err(e) => return f(Err(e)),
  82     };
  83     let mut last_err = None;
  84     for addr in addrs {
  85         match f(Ok(&addr)) {
  86             Ok(l) => return Ok(l),
  87             Err(e) => last_err = Some(e),
  88         }
  89     }
  90     Err(last_err.unwrap_or_else(|| {
  91         Error::new(ErrorKind::InvalidInput, "could not resolve to any addresses")
  92     }))
  93 }