Struct async_coap::datagram::AllowStdUdpSocket

pub struct AllowStdUdpSocket(_, _, _);

A wrapper around std::net::UdpSocket that implements AsyncDatagramSocket.

This can be used to allow the standard rust UdpSocket (which doesn't provide an asynchronous API) to be used in an asynchronous fashion, similar to [futures-preview::io::AllowStdio].

Note that by default this wrapper will block execution whenever one of the poll methods is called (An exception is any instance created with AllowStdUdpSocket::bind). You can fake true asynchronous behavior by calling set_nonblocking(true) or set_read_timeout(). In the case where a UDP message is not received when polled (or it times out waiting for a response), a futures_timer::Delay is used to schedule an appropriate duration (set via set_async_poll_interval()) after which it can try again. This is obviously sub-optimal, but that's the best that can be offered without becoming intrusive.

As such, it is really intended to be a convenience stop-gap to get things up and running quickly. For production code, you would want to use a AsyncDatagramSocket wrapper around something truly asynchronous, like [tokio-udp::UdpSocket].

Methods

impl AllowStdUdpSocket

pub fn from_std(udp_socket: UdpSocket) -> AllowStdUdpSocket

Upgrades the given std::net::UdpSocket to an instance of AllowStdUdpSocket.

Note that no operations are performed on udp_socket by this method. It is recommended that you call std::net::UdpSocket::set_nonblocking on the socket before using this method. See the documentation for AllowStdUdpSocket for more information.

pub fn bind<A>(addr: A) -> Result<AllowStdUdpSocket> where
    A: ToSocketAddrs, 

Analog to std::net::UdpSocket::bind to an instance of AllowStdUdpSocket.

If addr is successfully resolved, the underlying UdpSocket will already be configured in a non-blocking operation mode.

pub fn set_async_poll_interval(
    &mut self,
    dur: Option<Duration>
) -> Option<Duration>

Changes the async poll interval for this socket, returning the previous value.

A value of None indicates that no timed polling should be performed.

The default value is Some(DEFAULT_ASYNC_POLL_INTERVAL), or 30ms.

Methods from Deref<Target = UdpSocket>

pub fn recv_from(&self, buf: &mut [u8]) -> Result<(usize, SocketAddr), Error>

Receives a single datagram message on the socket. On success, returns the number of bytes read and the origin.

The function must be called with valid byte array buf of sufficient size to hold the message bytes. If a message is too long to fit in the supplied buffer, excess bytes may be discarded.

Examples

use std::net::UdpSocket;

let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
let mut buf = [0; 10];
let (number_of_bytes, src_addr) = socket.recv_from(&mut buf)
                                        .expect("Didn't receive data");
let filled_buf = &mut buf[..number_of_bytes];

pub fn peek_from(&self, buf: &mut [u8]) -> Result<(usize, SocketAddr), Error>

Receives a single datagram message on the socket, without removing it from the queue. On success, returns the number of bytes read and the origin.

The function must be called with valid byte array buf of sufficient size to hold the message bytes. If a message is too long to fit in the supplied buffer, excess bytes may be discarded.

Successive calls return the same data. This is accomplished by passing MSG_PEEK as a flag to the underlying recvfrom system call.

Do not use this function to implement busy waiting, instead use libc::poll to synchronize IO events on one or more sockets.

Examples

use std::net::UdpSocket;

let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
let mut buf = [0; 10];
let (number_of_bytes, src_addr) = socket.peek_from(&mut buf)
                                        .expect("Didn't receive data");
let filled_buf = &mut buf[..number_of_bytes];

pub fn send_to<A>(&self, buf: &[u8], addr: A) -> Result<usize, Error> where
    A: ToSocketAddrs, 

Sends data on the socket to the given address. On success, returns the number of bytes written.

Address type can be any implementor of ToSocketAddrs trait. See its documentation for concrete examples.

It is possible for addr to yield multiple addresses, but send_to will only send data to the first address yielded by addr.

This will return an error when the IP version of the local socket does not match that returned from ToSocketAddrs.

See issue #34202 for more details.

Examples

use std::net::UdpSocket;

let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
socket.send_to(&[0; 10], "127.0.0.1:4242").expect("couldn't send data");

pub fn peer_addr(&self) -> Result<SocketAddr, Error>

🔬 This is a nightly-only experimental API. (udp_peer_addr)

Returns the socket address of the remote peer this socket was connected to.

Examples

#![feature(udp_peer_addr)]
use std::net::{Ipv4Addr, SocketAddr, SocketAddrV4, UdpSocket};

let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
socket.connect("192.168.0.1:41203").expect("couldn't connect to address");
assert_eq!(socket.peer_addr().unwrap(),
           SocketAddr::V4(SocketAddrV4::new(Ipv4Addr::new(192, 168, 0, 1), 41203)));

If the socket isn't connected, it will return a NotConnected error.

#![feature(udp_peer_addr)]
use std::net::UdpSocket;

let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
assert_eq!(socket.peer_addr().unwrap_err().kind(),
           ::std::io::ErrorKind::NotConnected);

pub fn local_addr(&self) -> Result<SocketAddr, Error>

Returns the socket address that this socket was created from.

Examples

use std::net::{Ipv4Addr, SocketAddr, SocketAddrV4, UdpSocket};

let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
assert_eq!(socket.local_addr().unwrap(),
           SocketAddr::V4(SocketAddrV4::new(Ipv4Addr::new(127, 0, 0, 1), 34254)));

pub fn try_clone(&self) -> Result<UdpSocket, Error>

Creates a new independently owned handle to the underlying socket.

The returned UdpSocket is a reference to the same socket that this object references. Both handles will read and write the same port, and options set on one socket will be propagated to the other.

Examples

use std::net::UdpSocket;

let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
let socket_clone = socket.try_clone().expect("couldn't clone the socket");

pub fn set_read_timeout(&self, dur: Option<Duration>) -> Result<(), Error>

Sets the read timeout to the timeout specified.

If the value specified is None, then read calls will block indefinitely. An Err is returned if the zero Duration is passed to this method.

Platform-specific behavior

Platforms may return a different error code whenever a read times out as a result of setting this option. For example Unix typically returns an error of the kind WouldBlock, but Windows may return TimedOut.

Examples

use std::net::UdpSocket;

let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
socket.set_read_timeout(None).expect("set_read_timeout call failed");

An Err is returned if the zero Duration is passed to this method:

use std::io;
use std::net::UdpSocket;
use std::time::Duration;

let socket = UdpSocket::bind("127.0.0.1:34254").unwrap();
let result = socket.set_read_timeout(Some(Duration::new(0, 0)));
let err = result.unwrap_err();
assert_eq!(err.kind(), io::ErrorKind::InvalidInput)

pub fn set_write_timeout(&self, dur: Option<Duration>) -> Result<(), Error>

Sets the write timeout to the timeout specified.

If the value specified is None, then write calls will block indefinitely. An Err is returned if the zero Duration is passed to this method.

Platform-specific behavior

Platforms may return a different error code whenever a write times out as a result of setting this option. For example Unix typically returns an error of the kind WouldBlock, but Windows may return TimedOut.

Examples

use std::net::UdpSocket;

let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
socket.set_write_timeout(None).expect("set_write_timeout call failed");

An Err is returned if the zero Duration is passed to this method:

use std::io;
use std::net::UdpSocket;
use std::time::Duration;

let socket = UdpSocket::bind("127.0.0.1:34254").unwrap();
let result = socket.set_write_timeout(Some(Duration::new(0, 0)));
let err = result.unwrap_err();
assert_eq!(err.kind(), io::ErrorKind::InvalidInput)

pub fn read_timeout(&self) -> Result<Option<Duration>, Error>

Returns the read timeout of this socket.

If the timeout is None, then read calls will block indefinitely.

Examples

use std::net::UdpSocket;

let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
socket.set_read_timeout(None).expect("set_read_timeout call failed");
assert_eq!(socket.read_timeout().unwrap(), None);

pub fn write_timeout(&self) -> Result<Option<Duration>, Error>

Returns the write timeout of this socket.

If the timeout is None, then write calls will block indefinitely.

Examples

use std::net::UdpSocket;

let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
socket.set_write_timeout(None).expect("set_write_timeout call failed");
assert_eq!(socket.write_timeout().unwrap(), None);

pub fn set_broadcast(&self, broadcast: bool) -> Result<(), Error>

Sets the value of the SO_BROADCAST option for this socket.

When enabled, this socket is allowed to send packets to a broadcast address.

Examples

use std::net::UdpSocket;

let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
socket.set_broadcast(false).expect("set_broadcast call failed");

pub fn broadcast(&self) -> Result<bool, Error>

Gets the value of the SO_BROADCAST option for this socket.

For more information about this option, see set_broadcast.

Examples

use std::net::UdpSocket;

let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
socket.set_broadcast(false).expect("set_broadcast call failed");
assert_eq!(socket.broadcast().unwrap(), false);

pub fn set_multicast_loop_v4(
    &self,
    multicast_loop_v4: bool
) -> Result<(), Error>

Sets the value of the IP_MULTICAST_LOOP option for this socket.

If enabled, multicast packets will be looped back to the local socket. Note that this may not have any effect on IPv6 sockets.

Examples

use std::net::UdpSocket;

let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
socket.set_multicast_loop_v4(false).expect("set_multicast_loop_v4 call failed");

pub fn multicast_loop_v4(&self) -> Result<bool, Error>

Gets the value of the IP_MULTICAST_LOOP option for this socket.

For more information about this option, see set_multicast_loop_v4.

Examples

use std::net::UdpSocket;

let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
socket.set_multicast_loop_v4(false).expect("set_multicast_loop_v4 call failed");
assert_eq!(socket.multicast_loop_v4().unwrap(), false);

pub fn set_multicast_ttl_v4(&self, multicast_ttl_v4: u32) -> Result<(), Error>

Sets the value of the IP_MULTICAST_TTL option for this socket.

Indicates the time-to-live value of outgoing multicast packets for this socket. The default value is 1 which means that multicast packets don't leave the local network unless explicitly requested.

Note that this may not have any effect on IPv6 sockets.

Examples

use std::net::UdpSocket;

let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
socket.set_multicast_ttl_v4(42).expect("set_multicast_ttl_v4 call failed");

pub fn multicast_ttl_v4(&self) -> Result<u32, Error>

Gets the value of the IP_MULTICAST_TTL option for this socket.

For more information about this option, see set_multicast_ttl_v4.

Examples

use std::net::UdpSocket;

let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
socket.set_multicast_ttl_v4(42).expect("set_multicast_ttl_v4 call failed");
assert_eq!(socket.multicast_ttl_v4().unwrap(), 42);

pub fn set_multicast_loop_v6(
    &self,
    multicast_loop_v6: bool
) -> Result<(), Error>

Sets the value of the IPV6_MULTICAST_LOOP option for this socket.

Controls whether this socket sees the multicast packets it sends itself. Note that this may not have any affect on IPv4 sockets.

Examples

use std::net::UdpSocket;

let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
socket.set_multicast_loop_v6(false).expect("set_multicast_loop_v6 call failed");

pub fn multicast_loop_v6(&self) -> Result<bool, Error>

Gets the value of the IPV6_MULTICAST_LOOP option for this socket.

For more information about this option, see set_multicast_loop_v6.

Examples

use std::net::UdpSocket;

let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
socket.set_multicast_loop_v6(false).expect("set_multicast_loop_v6 call failed");
assert_eq!(socket.multicast_loop_v6().unwrap(), false);

pub fn set_ttl(&self, ttl: u32) -> Result<(), Error>

Sets the value for the IP_TTL option on this socket.

This value sets the time-to-live field that is used in every packet sent from this socket.

Examples

use std::net::UdpSocket;

let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
socket.set_ttl(42).expect("set_ttl call failed");

pub fn ttl(&self) -> Result<u32, Error>

Gets the value of the IP_TTL option for this socket.

For more information about this option, see set_ttl.

Examples

use std::net::UdpSocket;

let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
socket.set_ttl(42).expect("set_ttl call failed");
assert_eq!(socket.ttl().unwrap(), 42);

pub fn join_multicast_v4(
    &self,
    multiaddr: &Ipv4Addr,
    interface: &Ipv4Addr
) -> Result<(), Error>

Executes an operation of the IP_ADD_MEMBERSHIP type.

This function specifies a new multicast group for this socket to join. The address must be a valid multicast address, and interface is the address of the local interface with which the system should join the multicast group. If it's equal to INADDR_ANY then an appropriate interface is chosen by the system.

pub fn join_multicast_v6(
    &self,
    multiaddr: &Ipv6Addr,
    interface: u32
) -> Result<(), Error>

Executes an operation of the IPV6_ADD_MEMBERSHIP type.

This function specifies a new multicast group for this socket to join. The address must be a valid multicast address, and interface is the index of the interface to join/leave (or 0 to indicate any interface).

pub fn leave_multicast_v4(
    &self,
    multiaddr: &Ipv4Addr,
    interface: &Ipv4Addr
) -> Result<(), Error>

Executes an operation of the IP_DROP_MEMBERSHIP type.

For more information about this option, see join_multicast_v4.

pub fn leave_multicast_v6(
    &self,
    multiaddr: &Ipv6Addr,
    interface: u32
) -> Result<(), Error>

Executes an operation of the IPV6_DROP_MEMBERSHIP type.

For more information about this option, see join_multicast_v6.

pub fn take_error(&self) -> Result<Option<Error>, Error>

Gets the value of the SO_ERROR option on this socket.

This will retrieve the stored error in the underlying socket, clearing the field in the process. This can be useful for checking errors between calls.

Examples

use std::net::UdpSocket;

let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
match socket.take_error() {
    Ok(Some(error)) => println!("UdpSocket error: {:?}", error),
    Ok(None) => println!("No error"),
    Err(error) => println!("UdpSocket.take_error failed: {:?}", error),
}

pub fn connect<A>(&self, addr: A) -> Result<(), Error> where
    A: ToSocketAddrs, 

Connects this UDP socket to a remote address, allowing the send and recv syscalls to be used to send data and also applies filters to only receive data from the specified address.

If addr yields multiple addresses, connect will be attempted with each of the addresses until the underlying OS function returns no error. Note that usually, a successful connect call does not specify that there is a remote server listening on the port, rather, such an error would only be detected after the first send. If the OS returns an error for each of the specified addresses, the error returned from the last connection attempt (the last address) is returned.

Examples

Creates a UDP socket bound to 127.0.0.1:3400 and connect the socket to 127.0.0.1:8080:

use std::net::UdpSocket;

let socket = UdpSocket::bind("127.0.0.1:3400").expect("couldn't bind to address");
socket.connect("127.0.0.1:8080").expect("connect function failed");

Unlike in the TCP case, passing an array of addresses to the connect function of a UDP socket is not a useful thing to do: The OS will be unable to determine whether something is listening on the remote address without the application sending data.

pub fn send(&self, buf: &[u8]) -> Result<usize, Error>

Sends data on the socket to the remote address to which it is connected.

The connect method will connect this socket to a remote address. This method will fail if the socket is not connected.

Examples

use std::net::UdpSocket;

let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
socket.connect("127.0.0.1:8080").expect("connect function failed");
socket.send(&[0, 1, 2]).expect("couldn't send message");

pub fn recv(&self, buf: &mut [u8]) -> Result<usize, Error>

Receives a single datagram message on the socket from the remote address to which it is connected. On success, returns the number of bytes read.

The function must be called with valid byte array buf of sufficient size to hold the message bytes. If a message is too long to fit in the supplied buffer, excess bytes may be discarded.

The connect method will connect this socket to a remote address. This method will fail if the socket is not connected.

Examples

use std::net::UdpSocket;

let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
socket.connect("127.0.0.1:8080").expect("connect function failed");
let mut buf = [0; 10];
match socket.recv(&mut buf) {
    Ok(received) => println!("received {} bytes {:?}", received, &buf[..received]),
    Err(e) => println!("recv function failed: {:?}", e),
}

pub fn peek(&self, buf: &mut [u8]) -> Result<usize, Error>

Receives single datagram on the socket from the remote address to which it is connected, without removing the message from input queue. On success, returns the number of bytes peeked.

The function must be called with valid byte array buf of sufficient size to hold the message bytes. If a message is too long to fit in the supplied buffer, excess bytes may be discarded.

Successive calls return the same data. This is accomplished by passing MSG_PEEK as a flag to the underlying recv system call.

Do not use this function to implement busy waiting, instead use libc::poll to synchronize IO events on one or more sockets.

The connect method will connect this socket to a remote address. This method will fail if the socket is not connected.

Errors

This method will fail if the socket is not connected. The connect method will connect this socket to a remote address.

Examples

use std::net::UdpSocket;

let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
socket.connect("127.0.0.1:8080").expect("connect function failed");
let mut buf = [0; 10];
match socket.peek(&mut buf) {
    Ok(received) => println!("received {} bytes", received),
    Err(e) => println!("peek function failed: {:?}", e),
}

pub fn set_nonblocking(&self, nonblocking: bool) -> Result<(), Error>

Moves this UDP socket into or out of nonblocking mode.

This will result in recv, recv_from, send, and send_to operations becoming nonblocking, i.e., immediately returning from their calls. If the IO operation is successful, Ok is returned and no further action is required. If the IO operation could not be completed and needs to be retried, an error with kind io::ErrorKind::WouldBlock is returned.

On Unix platforms, calling this method corresponds to calling fcntl FIONBIO. On Windows calling this method corresponds to calling ioctlsocket FIONBIO.

Examples

Creates a UDP socket bound to 127.0.0.1:7878 and read bytes in nonblocking mode:

use std::io;
use std::net::UdpSocket;

let socket = UdpSocket::bind("127.0.0.1:7878").unwrap();
socket.set_nonblocking(true).unwrap();

let mut buf = [0; 10];
let (num_bytes_read, _) = loop {
    match socket.recv_from(&mut buf) {
        Ok(n) => break n,
        Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
            // wait until network socket is ready, typically implemented
            // via platform-specific APIs such as epoll or IOCP
            wait_for_fd();
        }
        Err(e) => panic!("encountered IO error: {}", e),
    }
};
println!("bytes: {:?}", &buf[..num_bytes_read]);

Trait Implementations

impl AsyncDatagramSocket for AllowStdUdpSocket

impl DatagramSocketTypes for AllowStdUdpSocket

type SocketAddr = SocketAddr

The "SocketAddr" type used by this "socket". Typically std::net::SocketAddr.

type Error = Error

The error type for errors emitted from this socket. Typically std::io::Error.

fn local_addr(&self) -> Result<Self::SocketAddr, Self::Error>

Returns the local SocketAddr of this "socket".

fn lookup_host(
    host: &str,
    port: u16
) -> Result<IntoIter<Self::SocketAddr>, Self::Error> where
    Self: Sized, 

Performs a blocking hostname lookup.

impl AsyncSendTo for AllowStdUdpSocket

fn poll_send_to<B>(
    self: Pin<&Self>,
    cx: &mut Context,
    buf: &[u8],
    addr: B
) -> Poll<Result<usize, Self::Error>> where
    B: ToSocketAddrs<SocketAddr = Self::SocketAddr, Error = Self::Error>, 

A non-blocking, poll_* version of std::net::UdpSocket::send_to.

fn send_to<B>(&self, buf: &[u8], addr: B) -> Result<usize, Self::Error> where
    B: ToSocketAddrs<SocketAddr = Self::SocketAddr, Error = Self::Error>, 

A synchronous version of AsyncSendTo::poll_send_to. If this isn't overridden by the trait's implementation, the default version will call poll_send_to() and panics if it returns Poll::Pending.

Important traits for NextSendToFuture<'a, 'b, T>

impl<'a, 'b, T: ?Sized> Future for NextSendToFuture<'a, 'b, T> where
    T: DatagramSocketTypes + AsyncSendTo,  type Output = Result<usize, T::Error>;

fn next_send_to<'a, 'b, B>(
    &'a self,
    buf: &'b [u8],
    addr: B
) -> NextSendToFuture<'a, 'b, Self> where
    B: ToSocketAddrs<SocketAddr = Self::SocketAddr, Error = Self::Error>, 

Returns a future that uses AsyncSendTo::poll_send_to.

impl AsyncRecvFrom for AllowStdUdpSocket

fn poll_recv_from(
    self: Pin<&Self>,
    cx: &mut Context,
    buf: &mut [u8]
) -> Poll<Result<(usize, Self::SocketAddr, Option<Self::SocketAddr>), Self::Error>>

A non-blocking, poll_* version of std::net::UdpSocket::recv_from that can optionally provide the destination (local) SocketAddr.

Important traits for NextRecvFromFuture<'a, 'b, T>

impl<'a, 'b, T: AsyncRecvFrom + ?Sized> Future for NextRecvFromFuture<'a, 'b, T> type Output = Result<(usize, T::SocketAddr, Option<T::SocketAddr>), T::Error>;

fn next_recv_from<'a, 'b>(
    &'a self,
    buf: &'b mut [u8]
) -> NextRecvFromFuture<'a, 'b, Self>

Returns a future that uses poll_recv_from.

impl MulticastSocket for AllowStdUdpSocket

type IpAddr = IpAddr

The "address" type for this socket.

fn join_multicast<A>(&self, addr: A) -> Result<(), Self::Error> where
    A: Into<Self::IpAddr>, 

Attempts to join the given multicast group.

fn leave_multicast<A>(&self, addr: A) -> Result<(), Self::Error> where
    A: Into<Self::IpAddr>, 

Attempts to leave the given multicast group.

impl Unpin for AllowStdUdpSocket

impl Deref for AllowStdUdpSocket

type Target = UdpSocket

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl Debug for AllowStdUdpSocket

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.