# [−] [src] Struct mio::net::UdpSocket

    pub struct UdpSocket { /* fields omitted */ }

A User Datagram Protocol socket.

This is an implementation of a bound UDP socket. This supports both IPv4 and IPv6 addresses, and there is no corresponding notion of a server because UDP is a datagram protocol.

# Examples

    // An Echo program:
    // SENDER -> sends a message.
    // ECHOER -> listens and prints the message received.

    use mio::net::UdpSocket;
    use mio::{Events, Interest, Poll, Token};
    use std::time::Duration;

    const SENDER: Token = Token(0);
    const ECHOER: Token = Token(1);

    // This operation will fail if the address is in use, so we select different ports for each
    // socket.
    let mut sender_socket = UdpSocket::bind("127.0.0.1:0".parse()?)?;
    let mut echoer_socket = UdpSocket::bind("127.0.0.1:0".parse()?)?;

    // If we do not use connect here, SENDER and ECHOER would need to call send_to and recv_from
    // respectively.
    sender_socket.connect(echoer_socket.local_addr()?)?;

    // We need a Poll to check if SENDER is ready to be written into, and if ECHOER is ready to be
    // read from.
    let mut poll = Poll::new()?;

    // We register our sockets here so that we can check if they are ready to be written/read.
    poll.registry().register(&mut sender_socket, SENDER, Interest::WRITABLE)?;
    poll.registry().register(&mut echoer_socket, ECHOER, Interest::READABLE)?;

    let msg_to_send = [9; 9];
    let mut buffer = [0; 9];

    let mut events = Events::with_capacity(128);
    loop {
        poll.poll(&mut events, Some(Duration::from_millis(100)))?;
        for event in events.iter() {
            match event.token() {
                // Our SENDER is ready to be written into.
                SENDER => {
                    let bytes_sent = sender_socket.send(&msg_to_send)?;
                    assert_eq!(bytes_sent, 9);
                    println!("sent {:?} -> {:?} bytes", msg_to_send, bytes_sent);
                },
                // Our ECHOER is ready to be read from.
                ECHOER => {
                    let num_recv = echoer_socket.recv(&mut buffer)?;
                    println!("echo {:?} -> {:?}", buffer, num_recv);
                    buffer = [0; 9];
                }
                _ => unreachable!()
            }
        }
    }

## Implementations

### `impl UdpSocket` [src]

#### `pub fn bind(addr: SocketAddr) -> Result<UdpSocket>` [src]

Creates a UDP socket from the given address.

# Examples

    use mio::net::UdpSocket;

    // We must bind it to an open address.
    let socket = match UdpSocket::bind("127.0.0.1:0".parse()?) {
        Ok(new_socket) => new_socket,
        Err(fail) => {
            // We panic! here, but you could try to bind it again on another address.
            panic!("Failed to bind socket. {:?}", fail);
        }
    };

    // Our socket was created, but we should not use it before checking it's readiness.

#### `pub fn from_std(socket: UdpSocket) -> UdpSocket` [src]

Creates a new `UdpSocket` from a standard `net::UdpSocket`.

This function is intended to be used to wrap a UDP socket from the standard library in the Mio equivalent. The conversion assumes nothing about the underlying socket; it is left up to the user to set it in non-blocking mode.

#### `pub fn local_addr(&self) -> Result<SocketAddr>` [src]

Returns the socket address that this socket was created from.

# Examples

    use mio::net::UdpSocket;

    let addr = "127.0.0.1:0".parse()?;
    let socket = UdpSocket::bind(addr)?;
    assert_eq!(socket.local_addr()?.ip(), addr.ip());

#### `pub fn send_to(&self, buf: &[u8], target: SocketAddr) -> Result<usize>` [src]

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.

# Examples

    use mio::net::UdpSocket;

    let socket = UdpSocket::bind("127.0.0.1:0".parse()?)?;

    // We must check if the socket is writable before calling send_to,
    // or we could run into a WouldBlock error.

    let bytes_sent = socket.send_to(&[9; 9], "127.0.0.1:11100".parse()?)?;
    assert_eq!(bytes_sent, 9);

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

Receives data from the socket. On success, returns the number of bytes read and the address from whence the data came.

# Notes

On Windows, if the data is larger than the buffer specified, the buffer is filled with the first part of the data, and recv_from returns the error WSAEMSGSIZE(10040). The excess data is lost. Make sure to always use a sufficiently large buffer to hold the maximum UDP packet size, which can be up to 65536 bytes in size.

# Examples

    use mio::net::UdpSocket;

    let socket = UdpSocket::bind("127.0.0.1:0".parse()?)?;

    // We must check if the socket is readable before calling recv_from,
    // or we could run into a WouldBlock error.

    let mut buf = [0; 9];
    let (num_recv, from_addr) = socket.recv_from(&mut buf)?;
    println!("Received {:?} -> {:?} bytes from {:?}", buf, num_recv, from_addr);

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

Receives data from the socket, without removing it from the input queue. On success, returns the number of bytes read and the address from whence the data came.

# Notes

On Windows, if the data is larger than the buffer specified, the buffer is filled with the first part of the data, and peek_from returns the error WSAEMSGSIZE(10040). The excess data is lost. Make sure to always use a sufficiently large buffer to hold the maximum UDP packet size, which can be up to 65536 bytes in size.

# Examples

    use mio::net::UdpSocket;

    let socket = UdpSocket::bind("127.0.0.1:0".parse()?)?;

    // We must check if the socket is readable before calling recv_from,
    // or we could run into a WouldBlock error.

    let mut buf = [0; 9];
    let (num_recv, from_addr) = socket.peek_from(&mut buf)?;
    println!("Received {:?} -> {:?} bytes from {:?}", buf, num_recv, from_addr);

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

Sends data on the socket to the address previously bound via connect(). On success, returns the number of bytes written.

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

Receives data from the socket previously bound with connect(). On success, returns the number of bytes read.

# Notes

On Windows, if the data is larger than the buffer specified, the buffer is filled with the first part of the data, and recv returns the error WSAEMSGSIZE(10040). The excess data is lost. Make sure to always use a sufficiently large buffer to hold the maximum UDP packet size, which can be up to 65536 bytes in size.

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

Receives data from the socket, without removing it from the input queue. On success, returns the number of bytes read.

# Notes

On Windows, if the data is larger than the buffer specified, the buffer is filled with the first part of the data, and peek returns the error WSAEMSGSIZE(10040). The excess data is lost. Make sure to always use a sufficiently large buffer to hold the maximum UDP packet size, which can be up to 65536 bytes in size.

#### `pub fn connect(&self, addr: SocketAddr) -> Result<()>` [src]

Connects the UDP socket setting the default destination for `send()` and limiting packets that are read via `recv` from the address specified in `addr`.

#### `pub fn set_broadcast(&self, on: bool) -> Result<()>` [src]

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 mio::net::UdpSocket;

    let broadcast_socket = UdpSocket::bind("127.0.0.1:0".parse()?)?;
    if broadcast_socket.broadcast()? == false {
        broadcast_socket.set_broadcast(true)?;
    }

    assert_eq!(broadcast_socket.broadcast()?, true);

#### `pub fn broadcast(&self) -> Result<bool>` [src]

Gets the value of the `SO_BROADCAST` option for this socket.

For more information about this option, see `set_broadcast`.

# Examples

    use mio::net::UdpSocket;

    let broadcast_socket = UdpSocket::bind("127.0.0.1:0".parse()?)?;
    assert_eq!(broadcast_socket.broadcast()?, false);

#### `pub fn set_multicast_loop_v4(&self, on: bool) -> Result<()>` [src]

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 affect on IPv6 sockets.

#### `pub fn multicast_loop_v4(&self) -> Result<bool>` [src]

Gets the value of the `IP_MULTICAST_LOOP` option for this socket.

For more information about this option, see `set_multicast_loop_v4`.

#### `pub fn set_multicast_ttl_v4(&self, ttl: u32) -> Result<()>` [src]

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 affect on IPv6 sockets.

#### `pub fn multicast_ttl_v4(&self) -> Result<u32>` [src]

Gets the value of the `IP_MULTICAST_TTL` option for this socket.

For more information about this option, see `set_multicast_ttl_v4`.

#### `pub fn set_multicast_loop_v6(&self, on: bool) -> Result<()>` [src]

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.

#### `pub fn multicast_loop_v6(&self) -> Result<bool>` [src]

Gets the value of the `IPV6_MULTICAST_LOOP` option for this socket.

For more information about this option, see `set_multicast_loop_v6`.

#### `pub fn set_ttl(&self, ttl: u32) -> Result<()>` [src]

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 mio::net::UdpSocket;

    let socket = UdpSocket::bind("127.0.0.1:0".parse()?)?;
    if socket.ttl()? < 255 {
        socket.set_ttl(255)?;
    }

    assert_eq!(socket.ttl()?, 255);

#### `pub fn ttl(&self) -> Result<u32>` [src]

Gets the value of the `IP_TTL` option for this socket.

For more information about this option, see `set_ttl`.

# Examples

    use mio::net::UdpSocket;

    let socket = UdpSocket::bind("127.0.0.1:0".parse()?)?;
    socket.set_ttl(255)?;

    assert_eq!(socket.ttl()?, 255);

#### `pub fn join_multicast_v4(
&self,
multiaddr: &Ipv4Addr,
interface: &Ipv4Addr
) -> Result<()>` [src]

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<()>` [src]

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<()>` [src]

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<()>` [src]

Executes an operation of the `IPV6_DROP_MEMBERSHIP` type.

For more information about this option, see `join_multicast_v6`.

#### `pub fn only_v6(&self) -> Result<bool>` [src]

Get the value of the `IPV6_V6ONLY` option on this socket.

#### `pub fn take_error(&self) -> Result<Option<Error>>` [src]

Get 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.

## Trait Implementations

### `impl AsRawFd for UdpSocket` [src]

#### `fn as_raw_fd(&self) -> RawFd` [src]

Extracts the raw file descriptor. Read more

### `impl Debug for UdpSocket` [src]

#### `fn fmt(&self, f: &mut Formatter<'_>) -> Result` [src]

Formats the value using the given formatter. Read more

### `impl FromRawFd for UdpSocket` [src]

#### `unsafe fn from_raw_fd(fd: RawFd) -> UdpSocket` [src]

Converts a `RawFd` to a `UdpSocket`.

# Notes

The caller is responsible for ensuring that the socket is in non-blocking mode.

### `impl IntoRawFd for UdpSocket` [src]

#### `fn into_raw_fd(self) -> RawFd` [src]

Consumes this object, returning the raw underlying file descriptor. Read more

### `impl Source for UdpSocket` [src]

#### `fn register(
&mut self,
registry: &Registry,
token: Token,
interests: Interest
) -> Result<()>` [src]

Register `self` with the given `Registry` instance. Read more

#### `fn reregister(
&mut self,
registry: &Registry,
token: Token,
interests: Interest
) -> Result<()>` [src]

Re-register `self` with the given `Registry` instance. Read more

#### `fn deregister(&mut self, registry: &Registry) -> Result<()>` [src]

Deregister `self` from the given `Registry` instance. Read more

## Auto Trait Implementations

### `impl RefUnwindSafe for UdpSocket`

### `impl Send for UdpSocket`

### `impl Sync for UdpSocket`

### `impl Unpin for UdpSocket`

### `impl UnwindSafe for UdpSocket`

## Blanket Implementations

### `impl<T> Any for T where
T: 'static + ?Sized,` [src]

#### `pub fn type_id(&self) -> TypeId` [src]

Gets the `TypeId` of `self`. Read more

### `impl<T> Borrow<T> for T where
T: ?Sized,` [src]

#### `pub fn borrow(&self) -> &T` [src]

Immutably borrows from an owned value. Read more

### `impl<T> BorrowMut<T> for T where
T: ?Sized,` [src]

#### `pub fn borrow_mut(&mut self) -> &mut T` [src]

Mutably borrows from an owned value. Read more

### `impl<T> From<T> for T` [src]

#### `pub fn from(t: T) -> T` [src]

Performs the conversion.

### `impl<T, U> Into<U> for T where
U: From<T>,` [src]

#### `pub fn into(self) -> U` [src]

Performs the conversion.

### `impl<T, U> TryFrom<U> for T where
U: Into<T>,` [src]

#### `type Error = Infallible`

The type returned in the event of a conversion error.

#### `pub fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>` [src]

Performs the conversion.

### `impl<T, U> TryInto<U> for T where
U: TryFrom<T>,` [src]

#### `type Error = <U as TryFrom<T>>::Error`

The type returned in the event of a conversion error.

#### `pub fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>` [src]

Performs the conversion.