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//! Extension traits for `TcpListener`, `UdpSocket`, and `Pool`.
//!
//! cap-std's [`TcpListener`], following the Rust standard library
//! `TcpListener`, combines the `socket`, `bind`, `listen`, and `connect`
//! operations of the POSIX socket API into a single `bind` or `connect`
//! operation. In some use cases, it's desirable to perform the steps
//! separately.
//!
//! This API adds extension traits to cap-std's `TcpListener`, `UdpSocket`,
//! and `Pool` which support the following sequence for accepting incoming
//! connections:
//!
//! - [`TcpListenerExt::new`] performs a `socket` and returns a new
//! `TcpListener` that is not yet bound.
//! - [`Pool::bind_existing_tcp_listener`] performs a `bind`, checking that
//! the address is in the `Pool`.
//! - [`TcpListenerExt::listen`] performs a `listen`.
//! - Then, the regular [`TcpListener::accept`] may be used to accept new
//! connections. Alternatively, [`TcpListener::accept_with`] may be used.
//!
//! and the following sequence for initiating outgoing connections:
//!
//! - [`TcpListenerExt::new`] performs a `socket` and returns a new
//! `TcpListener` that is not yet connected.
//! - [`Pool::connect_into_tcp_stream`] performs a `connect`, checking that
//! the address is in the `Pool`.
//!
//! [`TcpListenerExt::new`] and [`TcpListener::accept_with`] additionally
//! have [`Blocking`] arguments for requesting non-blocking operation.
//!
//! Similar API adaptations are available for UDP sockets as well.
#![deny(missing_docs)]
#![forbid(unsafe_code)]
#![doc(
html_logo_url = "https://raw.githubusercontent.com/bytecodealliance/cap-std/main/media/cap-std.svg"
)]
#![doc(
html_favicon_url = "https://raw.githubusercontent.com/bytecodealliance/cap-std/main/media/cap-std.ico"
)]
use cap_primitives::net::no_socket_addrs;
use cap_std::net::{IpAddr, Pool, SocketAddr, TcpListener, TcpStream, ToSocketAddrs, UdpSocket};
use rustix::fd::OwnedFd;
use std::io;
/// Address families supported by [`TcpListenerExt::new`] and
/// [`UdpSocketExt::new`].
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
pub enum AddressFamily {
/// IPv4
Ipv4,
/// IPv6
Ipv6,
}
impl AddressFamily {
/// Return the `AddressFamily` of an IP address.
pub fn of_ip_addr(ip_addr: IpAddr) -> Self {
match ip_addr {
IpAddr::V4(_) => AddressFamily::Ipv4,
IpAddr::V6(_) => AddressFamily::Ipv6,
}
}
/// Return the `AddressFamily` of a socket address.
pub fn of_socket_addr(socket_addr: SocketAddr) -> Self {
match socket_addr {
SocketAddr::V4(_) => AddressFamily::Ipv4,
SocketAddr::V6(_) => AddressFamily::Ipv6,
}
}
}
impl From<AddressFamily> for rustix::net::AddressFamily {
fn from(address_family: AddressFamily) -> Self {
match address_family {
AddressFamily::Ipv4 => rustix::net::AddressFamily::INET,
AddressFamily::Ipv6 => rustix::net::AddressFamily::INET6,
}
}
}
/// Select blocking or non-blocking mode.
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
pub enum Blocking {
/// Non-blocking
No,
/// Blocking
Yes,
}
/// A trait for extending `TcpListener` types.
pub trait TcpListenerExt: private::Sealed + Sized {
/// Creates a new TCP socket with the given address family.
///
/// The created socket is not bound or connected to any address and may be
/// used for either listening or connecting. Use
/// [`PoolExt::bind_existing_tcp_listener`] to bind it in preparation for
/// listening, or [`PoolExt::connect_into_tcp_stream`] to initiate a
/// connection.
///
/// This is similar to [`Pool::bind_tcp_listener`] in that it creates a TCP
/// socket, however it does not perform the `bind` or `listen` steps. And,
/// it has a `blocking` argument to select blocking or non-blocking mode
/// for the created socket.
///
/// And it's similar to [`Pool::connect_tcp_stream`] in that it creates a
/// TCP socket, however it does not perform the `connect` step. And, it has
/// a `blocking` argument to select blocking or non-blocking mode for the
/// created socket.
fn new(address_family: AddressFamily, blocking: Blocking) -> io::Result<Self>;
/// Enble listening in a `TcpListener`.
///
/// A newly-created [`TcpListener`] created with [`TcpListenerExt::new`]
/// and bound with [`PoolExt::bind_existing_tcp_listener`] is not yet
/// listening; this function enables listening. After this, the listener
/// may accept new connections with [`accept`] or [`accept_with`].
///
/// This is similar to [`Pool::bind_tcp_listener`] in that it performs the
/// `listen` step, however it does not create the socket itself, or bind
/// it.
///
/// The `backlog` argument specifies an optional hint to the implementation
/// about how many connections can be waiting before new connections are
/// refused or ignored.
///
/// [`accept`]: TcpListener::accept
/// [`accept_with`]: TcpListenerExt::accept_with
fn listen(&self, backlog: Option<i32>) -> io::Result<()>;
/// Similar to [`accept`], but the resulting TCP connection are optionally
/// set to non-blocking mode.
///
/// The `accept` call itself may still block, if the socket is in blocking
/// mode.
///
/// [`accept`]: TcpListener::accept
fn accept_with(&self, blocking: Blocking) -> io::Result<(TcpStream, SocketAddr)>;
}
impl TcpListenerExt for TcpListener {
fn new(address_family: AddressFamily, blocking: Blocking) -> io::Result<Self> {
socket(address_family, blocking, rustix::net::SocketType::STREAM).map(Self::from)
}
fn listen(&self, backlog: Option<i32>) -> io::Result<()> {
let backlog = backlog.unwrap_or_else(default_backlog);
Ok(rustix::net::listen(self, backlog)?)
}
fn accept_with(&self, blocking: Blocking) -> io::Result<(TcpStream, SocketAddr)> {
let (stream, addr) = rustix::net::acceptfrom_with(self, socket_flags(blocking))?;
set_socket_flags(&stream, blocking)?;
// We know have a TCP socket, so we know we'll get an IP address.
let addr = match addr {
Some(rustix::net::SocketAddrAny::V4(v4)) => SocketAddr::V4(v4),
Some(rustix::net::SocketAddrAny::V6(v6)) => SocketAddr::V6(v6),
_ => unreachable!(),
};
Ok((TcpStream::from(stream), addr))
}
}
/// A trait for extending `UdpSocket` types.
pub trait UdpSocketExt: private::Sealed + Sized {
/// Creates a new `UdpSocket` with the given address family.
///
/// The created socket is initially not bound or connected to any address.
/// Use [`PoolExt::bind_existing_udp_socket`] to bind it, or
/// [`PoolExt::connect_existing_udp_socket`] to initiate a connection.
///
/// This is similar to [`Pool::bind_udp_socket`] in that it creates a UDP
/// socket, however it does not perform the `bind`. And, it has a
/// `blocking` argument to select blocking or non-blocking mode for the
/// created socket.
///
/// And it's similar to [`Pool::connect_udp_socket`] in that it creates a
/// UDP socket, however it does not perform the `connect` step. And, it has
/// a `blocking` argument to select blocking or non-blocking mode for the
/// created socket.
fn new(address_family: AddressFamily, blocking: Blocking) -> io::Result<Self>;
}
impl UdpSocketExt for UdpSocket {
fn new(address_family: AddressFamily, blocking: Blocking) -> io::Result<Self> {
socket(address_family, blocking, rustix::net::SocketType::DGRAM).map(Self::from)
}
}
/// A trait for extending `Pool` types.
///
/// These functions have a `ToSocketAddrs` argument, which can return either
/// IPv4 or IPv6 addresses, however they also require the socket to be created
/// with a specific address family up front. Consequently, it's recommended to
/// do address resolution outside of this API and just pass resolved
/// `SocketAddr`s in.
pub trait PoolExt: private::Sealed {
/// Bind a [`TcpListener`] to the specified address.
///
/// A newly-created `TcpListener` created with [`TcpListenerExt::new`]
/// has not been bound yet; this function binds it. Before it can accept
/// connections, it must be marked for listening with
/// [`TcpListenerExt::listen`].
///
/// This is similar to [`Pool::bind_tcp_listener`] in that it binds a TCP
/// socket, however it does not create the socket itself, or perform the
/// `listen` step.
///
/// This function ensures that the address to be bound is permitted by the
/// pool, and performs the bind. To perform these steps separately, create
/// a [`TcpBinder`] with [`Self::tcp_binder`] and use
/// [`TcpBinder::bind_existing_tcp_listener`].
fn bind_existing_tcp_listener<A: ToSocketAddrs>(
&self,
listener: &TcpListener,
addrs: A,
) -> io::Result<()>;
/// Bind a [`UdpSocket`] to the specified address.
///
/// A newly-created `UdpSocket` created with [`UdpSocketExt::new`] has not
/// been bound yet; this function binds it.
///
/// This is similar to [`Pool::bind_udp_socket`] in that it binds a UDP
/// socket, however it does not create the socket itself.
///
/// This function ensures that the address to be bound is permitted by the
/// pool, and performs the bind. To perform these steps separately, create
/// a [`UdpBinder`] with [`Self::udp_binder`] and use
/// [`UdpBinder::bind_existing_udp_socket`].
fn bind_existing_udp_socket<A: ToSocketAddrs>(
&self,
socket: &UdpSocket,
addrs: A,
) -> io::Result<()>;
/// Initiate a TCP connection, converting a [`TcpListener`] to a
/// [`TcpStream`].
///
/// This is simlar to [`Pool::connect_tcp_stream`] in that it performs a
/// TCP connection, but instead of creating a new socket itself it takes a
/// [`TcpListener`], such as one created with [`TcpListenerExt::new`].
///
/// Despite the name, this function uses the `TcpListener` type as a
/// generic socket container.
///
/// This function ensures that the address to connect to is permitted by
/// the pool, and performs the connect. To perform these steps separately,
/// create a [`TcpConnecter`] with [`Self::tcp_connecter`] and use
/// [`TcpConnecter::connect_into_tcp_stream`].
fn connect_into_tcp_stream<A: ToSocketAddrs>(
&self,
socket: TcpListener,
addrs: A,
) -> io::Result<TcpStream>;
/// Initiate a TCP connection on a socket.
///
/// This is simlar to [`Self::connect_into_tcp_stream`], however instead of
/// converting a `TcpListener` to a `TcpStream`, it leaves fd in the
/// existing `TcpListener`.
///
/// This function ensures that the address to connect to is permitted by
/// the pool, and performs the connect. To perform these steps separately,
/// create a [`TcpConnecter`] with [`Self::tcp_connecter`] and use
/// [`TcpConnecter::connect_existing_tcp_listener`].
fn connect_existing_tcp_listener<A: ToSocketAddrs>(
&self,
socket: &TcpListener,
addrs: A,
) -> io::Result<()>;
/// Initiate a UDP connection.
///
/// This is simlar to [`Pool::connect_udp_socket`] in that it performs a
/// UDP connection, but instead of creating a new socket itself it takes a
/// [`UdpSocket`], such as one created with [`UdpSocketExt::new`].
///
/// This function ensures that the address to connect to is permitted by
/// the pool, and performs the connect. To perform these steps separately,
/// create a [`UdpConnecter`] with [`Self::udp_connecter`] and use
/// [`UdpConnecter::connect_existing_udp_socket`].
fn connect_existing_udp_socket<A: ToSocketAddrs>(
&self,
socket: &UdpSocket,
addrs: A,
) -> io::Result<()>;
/// Create a TCP binder.
///
/// This is an alternative to [`Self::bind_existing_tcp_listener`]. It
/// checks that all the addresses in `addrs` are permitted for TCP binding
/// up front, and then records them in a [`TcpBinder`] which can then be
/// used to make repeated [`TcpBinder::bind_existing_tcp_listener`] calls.
fn tcp_binder<A: ToSocketAddrs>(&self, addrs: A) -> io::Result<TcpBinder>;
/// Create a UDP binder.
///
/// This is an alternative to [`Self::bind_existing_udp_socket`]. It checks
/// that all the addresses in `addrs` are permitted for UDP binding up
/// front, and then records them in a [`UdpBinder`] which can then be used
/// to make repeated [`UdpBinder::bind_existing_udp_socket`] calls.
fn udp_binder<A: ToSocketAddrs>(&self, addrs: A) -> io::Result<UdpBinder>;
/// Create a TCP connecter.
///
/// This is an alternative to [`Self::connect_into_tcp_stream`] and
/// [`Self::connect_existing_tcp_listener`]. It checks that all the
/// addresses in `addrs` are permitted for TCP connecting up front, and
/// then records them in a [`TcpConnecter`] which can then be used to make
/// repeated [`TcpConnecter::connect_into_tcp_stream`] and
/// [`TcpConnecter::connect_existing_tcp_listener`] calls.
fn tcp_connecter<A: ToSocketAddrs>(&self, addrs: A) -> io::Result<TcpConnecter>;
/// Create a UDP connecter.
///
/// This is an alternative to [`Self::connect_existing_udp_socket`]. It
/// checks that all the addresses in `addrs` are permitted for UDP
/// connecting up front, and then records them in a [`UdpConnecter`] which
/// can then be used to make repeated
/// [`UdpConnecter::connect_existing_udp_socket`] calls.
fn udp_connecter<A: ToSocketAddrs>(&self, addrs: A) -> io::Result<UdpConnecter>;
}
impl PoolExt for Pool {
fn bind_existing_tcp_listener<A: ToSocketAddrs>(
&self,
listener: &TcpListener,
addrs: A,
) -> io::Result<()> {
let addrs = addrs.to_socket_addrs()?;
let mut last_err = None;
for addr in addrs {
self._pool().check_addr(&addr)?;
set_reuseaddr(listener)?;
match rustix::net::bind(listener, &addr) {
Ok(()) => return Ok(()),
Err(err) => last_err = Some(err.into()),
}
}
match last_err {
Some(err) => Err(err),
None => Err(no_socket_addrs()),
}
}
fn bind_existing_udp_socket<A: ToSocketAddrs>(
&self,
socket: &UdpSocket,
addrs: A,
) -> io::Result<()> {
let addrs = addrs.to_socket_addrs()?;
let mut last_err = None;
for addr in addrs {
self._pool().check_addr(&addr)?;
match rustix::net::bind(socket, &addr) {
Ok(()) => return Ok(()),
Err(err) => last_err = Some(err),
}
}
match last_err {
Some(err) => Err(err.into()),
None => Err(no_socket_addrs()),
}
}
fn connect_into_tcp_stream<A: ToSocketAddrs>(
&self,
socket: TcpListener,
addrs: A,
) -> io::Result<TcpStream> {
self.connect_existing_tcp_listener(&socket, addrs)?;
Ok(TcpStream::from(OwnedFd::from(socket)))
}
fn connect_existing_tcp_listener<A: ToSocketAddrs>(
&self,
socket: &TcpListener,
addrs: A,
) -> io::Result<()> {
let addrs = addrs.to_socket_addrs()?;
let mut last_err = None;
for addr in addrs {
self._pool().check_addr(&addr)?;
match rustix::net::connect(socket, &addr) {
Ok(()) => return Ok(()),
Err(err) => last_err = Some(err),
}
}
match last_err {
Some(err) => Err(err.into()),
None => Err(no_socket_addrs()),
}
}
fn connect_existing_udp_socket<A: ToSocketAddrs>(
&self,
socket: &UdpSocket,
addrs: A,
) -> io::Result<()> {
let addrs = addrs.to_socket_addrs()?;
let mut last_err = None;
for addr in addrs {
self._pool().check_addr(&addr)?;
match rustix::net::connect(socket, &addr) {
Ok(()) => return Ok(()),
Err(err) => last_err = Some(err),
}
}
match last_err {
Some(err) => Err(err.into()),
None => Err(no_socket_addrs()),
}
}
fn tcp_binder<A: ToSocketAddrs>(&self, addrs: A) -> io::Result<TcpBinder> {
Ok(TcpBinder(check_addrs(self._pool(), addrs)?))
}
fn udp_binder<A: ToSocketAddrs>(&self, addrs: A) -> io::Result<UdpBinder> {
Ok(UdpBinder(check_addrs(self._pool(), addrs)?))
}
fn tcp_connecter<A: ToSocketAddrs>(&self, addrs: A) -> io::Result<TcpConnecter> {
Ok(TcpConnecter(check_addrs(self._pool(), addrs)?))
}
fn udp_connecter<A: ToSocketAddrs>(&self, addrs: A) -> io::Result<UdpConnecter> {
Ok(UdpConnecter(check_addrs(self._pool(), addrs)?))
}
}
/// Check all the addresses in `addrs` and return a new list of them.
fn check_addrs<A: ToSocketAddrs>(
pool: &cap_primitives::net::Pool,
addrs: A,
) -> io::Result<smallvec::SmallVec<[SocketAddr; 1]>> {
let mut checked = smallvec::SmallVec::new();
for addr in addrs.to_socket_addrs()? {
pool.check_addr(&addr)?;
checked.push(addr);
}
Ok(checked)
}
/// A utility for binding TCP listeners.
///
/// See [`PoolExt::tcp_binder`] for details.
pub struct TcpBinder(smallvec::SmallVec<[SocketAddr; 1]>);
impl TcpBinder {
/// Bind a [`TcpListener`].
///
/// A newly-created `TcpListener` created with [`TcpListenerExt::new`]
/// has not been bound yet; this function binds it. Before it can accept
/// connections, it must be marked for listening with
/// [`TcpListenerExt::listen`].
///
/// This is similar to [`Pool::bind_tcp_listener`] in that it binds a TCP
/// socket, however it does not create the socket itself, or perform the
/// `listen` step.
///
/// This is similar to [`PoolExt::bind_existing_tcp_listener`] except that
/// it uses a `TcpBinder` which contains addresses that have already been
/// checked against a `Pool`.
pub fn bind_existing_tcp_listener(&self, listener: &TcpListener) -> io::Result<()> {
let mut last_err = None;
for addr in &self.0 {
set_reuseaddr(listener)?;
match rustix::net::bind(listener, addr) {
Ok(()) => return Ok(()),
Err(err) => last_err = Some(err.into()),
}
}
match last_err {
Some(err) => Err(err),
None => Err(no_socket_addrs()),
}
}
}
/// A utility for binding UDP sockets.
///
/// See [`PoolExt::udp_binder`] for details.
pub struct UdpBinder(smallvec::SmallVec<[SocketAddr; 1]>);
impl UdpBinder {
/// Bind a [`UdpSocket`] to the specified address.
///
/// A newly-created `UdpSocket` created with [`UdpSocketExt::new`] has not
/// been bound yet; this function binds it.
///
/// This is similar to [`Pool::bind_udp_socket`] in that it binds a UDP
/// socket, however it does not create the socket itself.
///
/// This is similar to [`PoolExt::bind_existing_udp_socket`] except that
/// it uses a `UdpBinder` which contains addresses that have already been
/// checked against a `Pool`.
pub fn bind_existing_udp_socket(&self, socket: &UdpSocket) -> io::Result<()> {
let mut last_err = None;
for addr in &self.0 {
match rustix::net::bind(socket, addr) {
Ok(()) => return Ok(()),
Err(err) => last_err = Some(err.into()),
}
}
match last_err {
Some(err) => Err(err),
None => Err(no_socket_addrs()),
}
}
}
/// A utility for making TCP connections.
///
/// See [`PoolExt::tcp_connecter`] for details.
pub struct TcpConnecter(smallvec::SmallVec<[SocketAddr; 1]>);
impl TcpConnecter {
/// Initiate a TCP connection, converting a [`TcpListener`] to a
/// [`TcpStream`].
///
/// This is simlar to [`Pool::connect_tcp_stream`] in that it performs a
/// TCP connection, but instead of creating a new socket itself it takes a
/// [`TcpListener`], such as one created with [`TcpListenerExt::new`].
///
/// Despite the name, this function uses the `TcpListener` type as a
/// generic socket container.
///
/// This is similar to [`PoolExt::connect_into_tcp_stream`] except that
/// it uses a `TcpConnecter` which contains addresses that have already
/// been checked against a `Pool`.
pub fn connect_into_tcp_stream(&self, socket: TcpListener) -> io::Result<TcpStream> {
self.connect_existing_tcp_listener(&socket)?;
Ok(TcpStream::from(OwnedFd::from(socket)))
}
/// Initiate a TCP connection on a socket.
///
/// This is simlar to [`Pool::connect_into_tcp_stream`], however instead of
/// converting a `TcpListener` to a `TcpStream`, it leaves fd in the
/// existing `TcpListener`.
///
/// This is similar to [`PoolExt::connect_existing_tcp_listener`] except
/// that it uses a `TcpConnecter` which contains addresses that have
/// already been checked against a `Pool`.
pub fn connect_existing_tcp_listener(&self, socket: &TcpListener) -> io::Result<()> {
let mut last_err = None;
for addr in &self.0 {
match rustix::net::connect(socket, addr) {
Ok(()) => return Ok(()),
Err(err) => last_err = Some(err),
}
}
match last_err {
Some(err) => Err(err.into()),
None => Err(no_socket_addrs()),
}
}
}
/// A utility for making UDP connections.
///
/// See [`PoolExt::udp_connecter`] for details.
pub struct UdpConnecter(smallvec::SmallVec<[SocketAddr; 1]>);
impl UdpConnecter {
/// Initiate a UDP connection.
///
/// This is simlar to [`Pool::connect_udp_socket`] in that it performs a
/// UDP connection, but instead of creating a new socket itself it takes a
/// [`UdpSocket`], such as one created with [`UdpSocketExt::new`].
///
/// This is similar to [`PoolExt::connect_existing_udp_socket`] except that
/// it uses a `UdpConnecter` which contains addresses that have already
/// been checked against a `Pool`.
pub fn connect_existing_udp_socket(&self, socket: &UdpSocket) -> io::Result<()> {
let mut last_err = None;
for addr in &self.0 {
match rustix::net::connect(socket, addr) {
Ok(()) => return Ok(()),
Err(err) => last_err = Some(err),
}
}
match last_err {
Some(err) => Err(err.into()),
None => Err(no_socket_addrs()),
}
}
}
fn socket(
address_family: AddressFamily,
blocking: Blocking,
socket_type: rustix::net::SocketType,
) -> io::Result<OwnedFd> {
// The Rust standard library has code to call `WSAStartup`, which is needed
// on Windows before we do any other Winsock2 calls, so just make a useless
// API call once.
#[cfg(windows)]
{
use std::sync::Once;
static START: Once = Once::new();
START.call_once(|| {
std::net::TcpStream::connect(std::net::SocketAddrV4::new(
std::net::Ipv4Addr::UNSPECIFIED,
0,
))
.unwrap_err();
});
}
// Create the socket, using the desired flags if we can.
let socket = rustix::net::socket_with(
address_family.into(),
socket_type,
socket_flags(blocking),
None,
)?;
// Set the desired flags if we couldn't set them at creation.
set_socket_flags(&socket, blocking)?;
Ok(socket)
}
/// Compute flags to pass to socket calls.
fn socket_flags(blocking: Blocking) -> rustix::net::SocketFlags {
let _ = blocking;
#[allow(unused_mut)]
let mut socket_flags = rustix::net::SocketFlags::empty();
// On platforms which do support `SOCK_CLOEXEC`, use it.
#[cfg(not(any(
windows,
target_os = "macos",
target_os = "ios",
target_os = "tvos",
target_os = "watchos",
target_os = "haiku"
)))]
{
socket_flags |= rustix::net::SocketFlags::CLOEXEC;
}
// On platforms which do support `SOCK_NONBLOCK`, use it.
#[cfg(not(any(
windows,
target_os = "macos",
target_os = "ios",
target_os = "tvos",
target_os = "watchos",
target_os = "haiku"
)))]
match blocking {
Blocking::Yes => (),
Blocking::No => socket_flags |= rustix::net::SocketFlags::NONBLOCK,
}
socket_flags
}
/// On platforms which don't support `SOCK_CLOEXEC` or `SOCK_NONBLOCK, set them
/// after creating the socket.
fn set_socket_flags(fd: &OwnedFd, blocking: Blocking) -> io::Result<()> {
let _ = fd;
let _ = blocking;
#[cfg(any(
target_os = "macos",
target_os = "ios",
target_os = "tvos",
target_os = "watchos"
))]
{
rustix::io::ioctl_fioclex(fd)?;
}
#[cfg(any(
windows,
target_os = "macos",
target_os = "ios",
target_os = "tvos",
target_os = "watchos"
))]
match blocking {
Blocking::Yes => (),
Blocking::No => rustix::io::ioctl_fionbio(fd, true)?,
}
#[cfg(target_os = "haiku")]
{
let mut flags = rustix::fs::fcntl_getfd(fd)?;
flags |= rustix::fs::OFlags::CLOEXEC;
match blocking {
Blocking::Yes => (),
Blocking::No => flags |= rustix::fs::OFlags::NONBLOCK,
}
rustix::fs::fcntl_setfd(fd, flags)?;
}
Ok(())
}
/// On platforms where it's desirable, set the `SO_REUSEADDR` option.
fn set_reuseaddr(listener: &TcpListener) -> io::Result<()> {
let _ = listener;
// The following logic is from
// <https://github.com/rust-lang/rust/blob/master/library/std/src/sys_common/net.rs>
// at revision defa2456246a8272ceace9c1cdccdf2e4c36175e.
// On platforms with Berkeley-derived sockets, this allows to quickly
// rebind a socket, without needing to wait for the OS to clean up the
// previous one.
//
// On Windows, this allows rebinding sockets which are actively in use,
// which allows “socket hijacking”, so we explicitly don't set it here.
// https://docs.microsoft.com/en-us/windows/win32/winsock/using-so-reuseaddr-and-so-exclusiveaddruse
#[cfg(not(windows))]
rustix::net::sockopt::set_socket_reuseaddr(listener, true)?;
Ok(())
}
/// Determine the platform-specific default backlog value.
fn default_backlog() -> i32 {
// The following logic is from
// <https://github.com/rust-lang/rust/blob/master/library/std/src/sys_common/net.rs>
// at revision defa2456246a8272ceace9c1cdccdf2e4c36175e.
// The 3DS doesn't support a big connection backlog. Sometimes
// it allows up to about 37, but other times it doesn't even
// accept 32. There may be a global limitation causing this.
#[cfg(target_os = "horizon")]
let backlog = 20;
// The default for all other platforms
#[cfg(not(target_os = "horizon"))]
let backlog = 128;
backlog
}
/// Seal the public traits for [future-proofing].
///
/// [future-proofing]: https://rust-lang.github.io/api-guidelines/future-proofing.html
mod private {
pub trait Sealed {}
impl Sealed for super::TcpListener {}
impl Sealed for super::UdpSocket {}
impl Sealed for super::Pool {}
}