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async-net/src/tcp.rs

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use std::fmt;
use std::io::{self, IoSlice, Read as _, Write as _};
use std::net::{Shutdown, SocketAddr};
#[cfg(unix)]
use std::os::unix::io::{AsFd, AsRawFd, BorrowedFd, OwnedFd, RawFd};
#[cfg(windows)]
use std::os::windows::io::{AsRawSocket, AsSocket, BorrowedSocket, OwnedSocket, RawSocket};
use std::panic::{RefUnwindSafe, UnwindSafe};
use std::pin::Pin;
use std::sync::Arc;
use std::task::{Context, Poll};
use async_io::Async;
use futures_lite::{prelude::*, ready};
use crate::addr::AsyncToSocketAddrs;
/// A TCP server, listening for connections.
///
/// After creating a [`TcpListener`] by [`bind`][`TcpListener::bind()`]ing it to an address, it
/// listens for incoming TCP connections. These can be accepted by calling
/// [`accept()`][`TcpListener::accept()`] or by awaiting items from the stream of
/// [`incoming`][`TcpListener::incoming()`] connections.
///
/// Cloning a [`TcpListener`] creates another handle to the same socket. The socket will be closed
/// when all handles to it are dropped.
///
/// The Transmission Control Protocol is specified in [IETF RFC 793].
///
/// [IETF RFC 793]: https://tools.ietf.org/html/rfc793
///
/// # Examples
///
/// ```no_run
/// use async_net::TcpListener;
/// use futures_lite::prelude::*;
///
/// # futures_lite::future::block_on(async {
/// let listener = TcpListener::bind("127.0.0.1:8080").await?;
/// let mut incoming = listener.incoming();
///
/// while let Some(stream) = incoming.next().await {
/// let mut stream = stream?;
/// stream.write_all(b"hello").await?;
/// }
/// # std::io::Result::Ok(()) });
/// ```
#[derive(Clone, Debug)]
pub struct TcpListener {
inner: Arc<Async<std::net::TcpListener>>,
}
impl TcpListener {
fn new(inner: Arc<Async<std::net::TcpListener>>) -> TcpListener {
TcpListener { inner }
}
/// Creates a new [`TcpListener`] bound to the given address.
///
/// Binding with a port number of 0 will request that the operating system assigns an available
/// port to this listener. The assigned port can be queried via the
/// [`local_addr()`][`TcpListener::local_addr()`] method.
///
/// If `addr` yields multiple addresses, binding will be attempted with each of the addresses
/// until one succeeds and returns the listener. If none of the addresses succeed in creating a
/// listener, the error from the last attempt is returned.
///
/// # Examples
///
/// Create a TCP listener bound to `127.0.0.1:80`:
///
/// ```no_run
/// use async_net::TcpListener;
///
/// # futures_lite::future::block_on(async {
/// let listener = TcpListener::bind("127.0.0.1:80").await?;
/// # std::io::Result::Ok(()) });
/// ```
///
/// Create a TCP listener bound to `127.0.0.1:80`. If that address is unavailable, then try
/// binding to `127.0.0.1:443`:
///
/// ```no_run
/// use async_net::{SocketAddr, TcpListener};
///
/// # futures_lite::future::block_on(async {
/// let addrs = [
/// SocketAddr::from(([127, 0, 0, 1], 80)),
/// SocketAddr::from(([127, 0, 0, 1], 443)),
/// ];
/// let listener = TcpListener::bind(&addrs[..]).await.unwrap();
/// # std::io::Result::Ok(()) });
pub async fn bind<A: AsyncToSocketAddrs>(addr: A) -> io::Result<TcpListener> {
let mut last_err = None;
for addr in addr.to_socket_addrs().await? {
match Async::<std::net::TcpListener>::bind(addr) {
Ok(listener) => return Ok(TcpListener::new(Arc::new(listener))),
Err(err) => last_err = Some(err),
}
}
Err(last_err.unwrap_or_else(|| {
io::Error::new(
io::ErrorKind::InvalidInput,
"could not resolve to any of the addresses",
)
}))
}
/// Returns the local address this listener is bound to.
///
/// # Examples
///
/// Bind to port 0 and then see which port was assigned by the operating system:
///
/// ```no_run
/// use async_net::{SocketAddr, TcpListener};
///
/// # futures_lite::future::block_on(async {
/// let listener = TcpListener::bind("127.0.0.1:0").await?;
/// println!("Listening on {}", listener.local_addr()?);
/// # std::io::Result::Ok(()) });
pub fn local_addr(&self) -> io::Result<SocketAddr> {
self.inner.get_ref().local_addr()
}
/// Accepts a new incoming connection.
///
/// Returns a TCP stream and the address it is connected to.
///
/// # Examples
///
/// ```no_run
/// use async_net::TcpListener;
///
/// # futures_lite::future::block_on(async {
/// let listener = TcpListener::bind("127.0.0.1:8080").await?;
/// let (stream, addr) = listener.accept().await?;
/// # std::io::Result::Ok(()) });
/// ```
pub async fn accept(&self) -> io::Result<(TcpStream, SocketAddr)> {
let (stream, addr) = self.inner.accept().await?;
Ok((TcpStream::new(Arc::new(stream)), addr))
}
/// Returns a stream of incoming connections.
///
/// Iterating over this stream is equivalent to calling [`accept()`][`TcpListener::accept()`]
/// in a loop. The stream of connections is infinite, i.e awaiting the next connection will
/// never result in [`None`].
///
/// # Examples
///
/// ```no_run
/// use async_net::TcpListener;
/// use futures_lite::prelude::*;
///
/// # futures_lite::future::block_on(async {
/// let listener = TcpListener::bind("127.0.0.1:0").await?;
/// let mut incoming = listener.incoming();
///
/// while let Some(stream) = incoming.next().await {
/// let mut stream = stream?;
/// stream.write_all(b"hello").await?;
/// }
/// # std::io::Result::Ok(()) });
/// ```
pub fn incoming(&self) -> Incoming<'_> {
Incoming {
incoming: Box::pin(self.inner.incoming()),
}
}
/// Gets the value of the `IP_TTL` option for this socket.
///
/// This option configures the time-to-live field that is used in every packet sent from this
/// socket.
///
/// # Examples
///
/// ```no_run
/// use async_net::TcpListener;
///
/// # futures_lite::future::block_on(async {
/// let listener = TcpListener::bind("127.0.0.1:80").await?;
/// listener.set_ttl(100)?;
/// assert_eq!(listener.ttl()?, 100);
/// # std::io::Result::Ok(()) });
/// ```
pub fn ttl(&self) -> io::Result<u32> {
self.inner.get_ref().ttl()
}
/// Sets the value of the `IP_TTL` option for this socket.
///
/// This option configures the time-to-live field that is used in every packet sent from this
/// socket.
///
/// # Examples
///
/// ```no_run
/// use async_net::TcpListener;
///
/// # futures_lite::future::block_on(async {
/// let listener = TcpListener::bind("127.0.0.1:80").await?;
/// listener.set_ttl(100)?;
/// # std::io::Result::Ok(()) });
/// ```
pub fn set_ttl(&self, ttl: u32) -> io::Result<()> {
self.inner.get_ref().set_ttl(ttl)
}
}
impl From<Async<std::net::TcpListener>> for TcpListener {
fn from(listener: Async<std::net::TcpListener>) -> TcpListener {
TcpListener::new(Arc::new(listener))
}
}
impl TryFrom<std::net::TcpListener> for TcpListener {
type Error = io::Error;
fn try_from(listener: std::net::TcpListener) -> io::Result<TcpListener> {
Ok(TcpListener::new(Arc::new(Async::new(listener)?)))
}
}
impl From<TcpListener> for Arc<Async<std::net::TcpListener>> {
fn from(val: TcpListener) -> Self {
val.inner
}
}
#[cfg(unix)]
impl AsRawFd for TcpListener {
fn as_raw_fd(&self) -> RawFd {
self.inner.as_raw_fd()
}
}
#[cfg(unix)]
impl AsFd for TcpListener {
fn as_fd(&self) -> BorrowedFd<'_> {
self.inner.get_ref().as_fd()
}
}
#[cfg(unix)]
impl TryFrom<OwnedFd> for TcpListener {
type Error = io::Error;
fn try_from(value: OwnedFd) -> Result<Self, Self::Error> {
Self::try_from(std::net::TcpListener::from(value))
}
}
#[cfg(windows)]
impl AsRawSocket for TcpListener {
fn as_raw_socket(&self) -> RawSocket {
self.inner.as_raw_socket()
}
}
#[cfg(windows)]
impl AsSocket for TcpListener {
fn as_socket(&self) -> BorrowedSocket<'_> {
self.inner.get_ref().as_socket()
}
}
#[cfg(windows)]
impl TryFrom<OwnedSocket> for TcpListener {
type Error = io::Error;
fn try_from(value: OwnedSocket) -> Result<Self, Self::Error> {
Self::try_from(std::net::TcpListener::from(value))
}
}
/// A stream of incoming TCP connections.
///
/// This stream is infinite, i.e awaiting the next connection will never result in [`None`]. It is
/// created by the [`TcpListener::incoming()`] method.
pub struct Incoming<'a> {
incoming:
Pin<Box<dyn Stream<Item = io::Result<Async<std::net::TcpStream>>> + Send + Sync + 'a>>,
}
impl Stream for Incoming<'_> {
type Item = io::Result<TcpStream>;
fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
let res = ready!(Pin::new(&mut self.incoming).poll_next(cx));
Poll::Ready(res.map(|res| res.map(|stream| TcpStream::new(Arc::new(stream)))))
}
}
impl fmt::Debug for Incoming<'_> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "Incoming {{ ... }}")
}
}
/// A TCP connection.
///
/// A [`TcpStream`] can be created by [`connect`][`TcpStream::connect()`]ing to an endpoint or by
/// [`accept`][`TcpListener::accept()`]ing an incoming connection.
///
/// [`TcpStream`] is a bidirectional stream that implements traits [`AsyncRead`] and
/// [`AsyncWrite`].
///
/// Cloning a [`TcpStream`] creates another handle to the same socket. The socket will be closed
/// when all handles to it are dropped. The reading and writing portions of the connection can also
/// be shut down individually with the [`shutdown()`][`TcpStream::shutdown()`] method.
///
/// The Transmission Control Protocol is specified in [IETF RFC 793].
///
/// [IETF RFC 793]: https://tools.ietf.org/html/rfc793
///
/// # Examples
///
/// ```no_run
/// use async_net::TcpStream;
/// use futures_lite::prelude::*;
///
/// # futures_lite::future::block_on(async {
/// let mut stream = TcpStream::connect("127.0.0.1:8080").await?;
/// stream.write_all(b"hello").await?;
///
/// let mut buf = vec![0u8; 1024];
/// let n = stream.read(&mut buf).await?;
/// # std::io::Result::Ok(()) });
/// ```
pub struct TcpStream {
inner: Arc<Async<std::net::TcpStream>>,
readable: Option<async_io::ReadableOwned<std::net::TcpStream>>,
writable: Option<async_io::WritableOwned<std::net::TcpStream>>,
}
impl UnwindSafe for TcpStream {}
impl RefUnwindSafe for TcpStream {}
impl TcpStream {
fn new(inner: Arc<Async<std::net::TcpStream>>) -> TcpStream {
TcpStream {
inner,
readable: None,
writable: None,
}
}
/// Creates a TCP connection to the specified address.
///
/// This method will create a new TCP socket and attempt to connect it to the provided `addr`,
///
/// If `addr` yields multiple addresses, connecting will be attempted with each of the
/// addresses until connecting to one succeeds. If none of the addresses result in a successful
/// connection, the error from the last connect attempt is returned.
///
/// # Examples
///
/// Connect to `example.com:80`:
///
/// ```
/// use async_net::TcpStream;
///
/// # futures_lite::future::block_on(async {
/// let stream = TcpStream::connect("example.com:80").await?;
/// # std::io::Result::Ok(()) });
/// ```
///
/// Connect to `127.0.0.1:8080`. If that fails, then try connecting to `127.0.0.1:8081`:
///
/// ```no_run
/// use async_net::{SocketAddr, TcpStream};
///
/// # futures_lite::future::block_on(async {
/// let addrs = [
/// SocketAddr::from(([127, 0, 0, 1], 8080)),
/// SocketAddr::from(([127, 0, 0, 1], 8081)),
/// ];
/// let stream = TcpStream::connect(&addrs[..]).await?;
/// # std::io::Result::Ok(()) });
/// ```
pub async fn connect<A: AsyncToSocketAddrs>(addr: A) -> io::Result<TcpStream> {
let mut last_err = None;
for addr in addr.to_socket_addrs().await? {
match Async::<std::net::TcpStream>::connect(addr).await {
Ok(stream) => return Ok(TcpStream::new(Arc::new(stream))),
Err(e) => last_err = Some(e),
}
}
Err(last_err.unwrap_or_else(|| {
io::Error::new(
io::ErrorKind::InvalidInput,
"could not connect to any of the addresses",
)
}))
}
/// Returns the local address this stream is bound to.
///
/// # Examples
///
/// ```
/// use async_net::TcpStream;
///
/// # futures_lite::future::block_on(async {
/// let stream = TcpStream::connect("example.com:80").await?;
/// println!("Local address is {}", stream.local_addr()?);
/// # std::io::Result::Ok(()) });
/// ```
pub fn local_addr(&self) -> io::Result<SocketAddr> {
self.inner.get_ref().local_addr()
}
/// Returns the remote address this stream is connected to.
///
/// # Examples
///
/// ```
/// use async_net::TcpStream;
///
/// # futures_lite::future::block_on(async {
/// let stream = TcpStream::connect("example.com:80").await?;
/// println!("Connected to {}", stream.peer_addr()?);
/// # std::io::Result::Ok(()) });
/// ```
pub fn peer_addr(&self) -> io::Result<SocketAddr> {
self.inner.get_ref().peer_addr()
}
/// Shuts down the read half, write half, or both halves of this connection.
///
/// This method will cause all pending and future I/O in the given directions to return
/// immediately with an appropriate value (see the documentation of [`Shutdown`]).
///
/// [`Shutdown`]: https://doc.rust-lang.org/std/net/enum.Shutdown.html
///
/// # Examples
///
/// ```no_run
/// use async_net::{Shutdown, TcpStream};
///
/// # futures_lite::future::block_on(async {
/// let stream = TcpStream::connect("127.0.0.1:8080").await?;
/// stream.shutdown(Shutdown::Both)?;
/// # std::io::Result::Ok(()) });
/// ```
pub fn shutdown(&self, how: std::net::Shutdown) -> std::io::Result<()> {
self.inner.get_ref().shutdown(how)
}
/// Receives data without removing it from the queue.
///
/// On success, returns the number of bytes peeked.
///
/// Successive calls return the same data. This is accomplished by passing `MSG_PEEK` as a flag
/// to the underlying `recv` system call.
///
/// # Examples
///
/// ```no_run
/// use async_net::TcpStream;
///
/// # futures_lite::future::block_on(async {
/// let stream = TcpStream::connect("127.0.0.1:8080").await?;
///
/// let mut buf = vec![0; 1024];
/// let n = stream.peek(&mut buf).await?;
/// # std::io::Result::Ok(()) });
/// ```
pub async fn peek(&self, buf: &mut [u8]) -> io::Result<usize> {
self.inner.peek(buf).await
}
/// Gets the value of the `TCP_NODELAY` option for this socket.
///
/// If set to `true`, this option disables the [Nagle algorithm][nagle-wiki]. This means that
/// written data is always sent as soon as possible, even if there is only a small amount of
/// it.
///
/// When set to `false`, written data is buffered until there is a certain amount to send out,
/// thereby avoiding the frequent sending of small packets.
///
/// [nagle-wiki]: https://en.wikipedia.org/wiki/Nagle%27s_algorithm
///
/// # Examples
///
/// ```no_run
/// use async_net::TcpStream;
///
/// # futures_lite::future::block_on(async {
/// let stream = TcpStream::connect("127.0.0.1:8080").await?;
/// println!("TCP_NODELAY is set to {}", stream.nodelay()?);
/// # std::io::Result::Ok(()) });
/// ```
pub fn nodelay(&self) -> io::Result<bool> {
self.inner.get_ref().nodelay()
}
/// Sets the value of the `TCP_NODELAY` option for this socket.
///
/// If set to `true`, this option disables the [Nagle algorithm][nagle-wiki]. This means that
/// written data is always sent as soon as possible, even if there is only a small amount of
/// it.
///
/// When set to `false`, written data is buffered until there is a certain amount to send out,
/// thereby avoiding the frequent sending of small packets.
///
/// [nagle-wiki]: https://en.wikipedia.org/wiki/Nagle%27s_algorithm
///
/// # Examples
///
/// ```no_run
/// use async_net::TcpStream;
///
/// # futures_lite::future::block_on(async {
/// let stream = TcpStream::connect("127.0.0.1:8080").await?;
/// stream.set_nodelay(false)?;
/// # std::io::Result::Ok(()) });
/// ```
pub fn set_nodelay(&self, nodelay: bool) -> io::Result<()> {
self.inner.get_ref().set_nodelay(nodelay)
}
/// Gets the value of the `IP_TTL` option for this socket.
///
/// This option configures the time-to-live field that is used in every packet sent from this
/// socket.
///
/// # Examples
///
/// ```no_run
/// use async_net::TcpStream;
///
/// # futures_lite::future::block_on(async {
/// let stream = TcpStream::connect("127.0.0.1:8080").await?;
/// println!("IP_TTL is set to {}", stream.ttl()?);
/// # std::io::Result::Ok(()) });
/// ```
pub fn ttl(&self) -> io::Result<u32> {
self.inner.get_ref().ttl()
}
/// Sets the value of the `IP_TTL` option for this socket.
///
/// This option configures the time-to-live field that is used in every packet sent from this
/// socket.
///
/// # Examples
///
/// ```no_run
/// use async_net::TcpStream;
///
/// # futures_lite::future::block_on(async {
/// let stream = TcpStream::connect("127.0.0.1:8080").await?;
/// stream.set_ttl(100)?;
/// # std::io::Result::Ok(()) });
/// ```
pub fn set_ttl(&self, ttl: u32) -> io::Result<()> {
self.inner.get_ref().set_ttl(ttl)
}
}
impl fmt::Debug for TcpStream {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
self.inner.fmt(f)
}
}
impl Clone for TcpStream {
fn clone(&self) -> TcpStream {
TcpStream::new(self.inner.clone())
}
}
impl From<Async<std::net::TcpStream>> for TcpStream {
fn from(stream: Async<std::net::TcpStream>) -> TcpStream {
TcpStream::new(Arc::new(stream))
}
}
impl From<TcpStream> for Arc<Async<std::net::TcpStream>> {
fn from(val: TcpStream) -> Self {
val.inner
}
}
impl TryFrom<std::net::TcpStream> for TcpStream {
type Error = io::Error;
fn try_from(stream: std::net::TcpStream) -> io::Result<TcpStream> {
Ok(TcpStream::new(Arc::new(Async::new(stream)?)))
}
}
#[cfg(unix)]
impl AsRawFd for TcpStream {
fn as_raw_fd(&self) -> RawFd {
self.inner.as_raw_fd()
}
}
#[cfg(unix)]
impl AsFd for TcpStream {
fn as_fd(&self) -> BorrowedFd<'_> {
self.inner.get_ref().as_fd()
}
}
#[cfg(unix)]
impl TryFrom<OwnedFd> for TcpStream {
type Error = io::Error;
fn try_from(value: OwnedFd) -> Result<Self, Self::Error> {
Self::try_from(std::net::TcpStream::from(value))
}
}
#[cfg(windows)]
impl AsRawSocket for TcpStream {
fn as_raw_socket(&self) -> RawSocket {
self.inner.as_raw_socket()
}
}
#[cfg(windows)]
impl AsSocket for TcpStream {
fn as_socket(&self) -> BorrowedSocket<'_> {
self.inner.get_ref().as_socket()
}
}
#[cfg(windows)]
impl TryFrom<OwnedSocket> for TcpStream {
type Error = io::Error;
fn try_from(value: OwnedSocket) -> Result<Self, Self::Error> {
Self::try_from(std::net::TcpStream::from(value))
}
}
impl AsyncRead for TcpStream {
fn poll_read(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &mut [u8],
) -> Poll<io::Result<usize>> {
loop {
// Attempt the non-blocking operation.
match self.inner.get_ref().read(buf) {
Err(err) if err.kind() == io::ErrorKind::WouldBlock => {}
res => {
self.readable = None;
return Poll::Ready(res);
}
}
// Initialize the future to wait for readiness.
if self.readable.is_none() {
self.readable = Some(self.inner.clone().readable_owned());
}
// Poll the future for readiness.
if let Some(f) = &mut self.readable {
let res = ready!(Pin::new(f).poll(cx));
self.readable = None;
res?;
}
}
}
}
impl AsyncWrite for TcpStream {
fn poll_write(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &[u8],
) -> Poll<io::Result<usize>> {
loop {
// Attempt the non-blocking operation.
match self.inner.get_ref().write(buf) {
Err(err) if err.kind() == io::ErrorKind::WouldBlock => {}
res => {
self.writable = None;
return Poll::Ready(res);
}
}
// Initialize the future to wait for readiness.
if self.writable.is_none() {
self.writable = Some(self.inner.clone().writable_owned());
}
// Poll the future for readiness.
if let Some(f) = &mut self.writable {
let res = ready!(Pin::new(f).poll(cx));
self.writable = None;
res?;
}
}
}
fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
loop {
// Attempt the non-blocking operation.
match self.inner.get_ref().flush() {
Err(err) if err.kind() == io::ErrorKind::WouldBlock => {}
res => {
self.writable = None;
return Poll::Ready(res);
}
}
// Initialize the future to wait for readiness.
if self.writable.is_none() {
self.writable = Some(self.inner.clone().writable_owned());
}
// Poll the future for readiness.
if let Some(f) = &mut self.writable {
let res = ready!(Pin::new(f).poll(cx));
self.writable = None;
res?;
}
}
}
fn poll_close(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<io::Result<()>> {
Poll::Ready(self.inner.get_ref().shutdown(Shutdown::Write))
}
fn poll_write_vectored(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
bufs: &[IoSlice<'_>],
) -> Poll<io::Result<usize>> {
loop {
// Attempt the non-blocking operation.
match self.inner.get_ref().write_vectored(bufs) {
Err(err) if err.kind() == io::ErrorKind::WouldBlock => {}
res => {
self.writable = None;
return Poll::Ready(res);
}
}
// Initialize the future to wait for readiness.
if self.writable.is_none() {
self.writable = Some(self.inner.clone().writable_owned());
}
// Poll the future for readiness.
if let Some(f) = &mut self.writable {
let res = ready!(Pin::new(f).poll(cx));
self.writable = None;
res?;
}
}
}
}
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