pub struct UdpSocket { /* private fields */ }
Expand description
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§
source§impl UdpSocket
impl UdpSocket
sourcepub fn bind(addr: SocketAddr) -> Result<UdpSocket>
pub fn bind(addr: SocketAddr) -> Result<UdpSocket>
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.
sourcepub fn from_std(socket: UdpSocket) -> UdpSocket
pub fn from_std(socket: UdpSocket) -> UdpSocket
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.
sourcepub fn local_addr(&self) -> Result<SocketAddr>
pub fn local_addr(&self) -> Result<SocketAddr>
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());
sourcepub fn peer_addr(&self) -> Result<SocketAddr>
pub fn peer_addr(&self) -> Result<SocketAddr>
Returns the socket address of the remote peer this socket was connected to.
Examples
use mio::net::UdpSocket;
let addr = "127.0.0.1:0".parse()?;
let peer_addr = "127.0.0.1:11100".parse()?;
let socket = UdpSocket::bind(addr)?;
socket.connect(peer_addr)?;
assert_eq!(socket.peer_addr()?.ip(), peer_addr.ip());
sourcepub fn send_to(&self, buf: &[u8], target: SocketAddr) -> Result<usize>
pub fn send_to(&self, buf: &[u8], target: SocketAddr) -> Result<usize>
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);
sourcepub fn recv_from(&self, buf: &mut [u8]) -> Result<(usize, SocketAddr)>
pub fn recv_from(&self, buf: &mut [u8]) -> Result<(usize, SocketAddr)>
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);
sourcepub fn peek_from(&self, buf: &mut [u8]) -> Result<(usize, SocketAddr)>
pub fn peek_from(&self, buf: &mut [u8]) -> Result<(usize, SocketAddr)>
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);
sourcepub fn send(&self, buf: &[u8]) -> Result<usize>
pub fn send(&self, buf: &[u8]) -> Result<usize>
Sends data on the socket to the address previously bound via connect(). On success, returns the number of bytes written.
sourcepub fn recv(&self, buf: &mut [u8]) -> Result<usize>
pub fn recv(&self, buf: &mut [u8]) -> Result<usize>
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.
sourcepub fn peek(&self, buf: &mut [u8]) -> Result<usize>
pub fn peek(&self, buf: &mut [u8]) -> Result<usize>
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.
sourcepub fn connect(&self, addr: SocketAddr) -> Result<()>
pub fn connect(&self, addr: SocketAddr) -> Result<()>
Connects the UDP socket setting the default destination for send()
and limiting packets that are read via recv
from the address specified
in addr
.
This may return a WouldBlock
in which case the socket connection
cannot be completed immediately, it usually means there are insufficient
entries in the routing cache.
sourcepub fn set_broadcast(&self, on: bool) -> Result<()>
pub fn set_broadcast(&self, on: bool) -> Result<()>
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);
sourcepub fn broadcast(&self) -> Result<bool>
pub fn broadcast(&self) -> Result<bool>
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);
sourcepub fn set_multicast_loop_v4(&self, on: bool) -> Result<()>
pub fn set_multicast_loop_v4(&self, on: bool) -> Result<()>
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.
sourcepub fn multicast_loop_v4(&self) -> Result<bool>
pub fn multicast_loop_v4(&self) -> Result<bool>
Gets the value of the IP_MULTICAST_LOOP
option for this socket.
For more information about this option, see
set_multicast_loop_v4
.
sourcepub fn set_multicast_ttl_v4(&self, ttl: u32) -> Result<()>
pub fn set_multicast_ttl_v4(&self, ttl: u32) -> Result<()>
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.
sourcepub fn multicast_ttl_v4(&self) -> Result<u32>
pub fn multicast_ttl_v4(&self) -> Result<u32>
Gets the value of the IP_MULTICAST_TTL
option for this socket.
For more information about this option, see
set_multicast_ttl_v4
.
sourcepub fn set_multicast_loop_v6(&self, on: bool) -> Result<()>
pub fn set_multicast_loop_v6(&self, on: bool) -> Result<()>
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.
sourcepub fn multicast_loop_v6(&self) -> Result<bool>
pub fn multicast_loop_v6(&self) -> Result<bool>
Gets the value of the IPV6_MULTICAST_LOOP
option for this socket.
For more information about this option, see
set_multicast_loop_v6
.
sourcepub fn set_ttl(&self, ttl: u32) -> Result<()>
pub fn set_ttl(&self, ttl: u32) -> Result<()>
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);
sourcepub fn join_multicast_v4(
&self,
multiaddr: &Ipv4Addr,
interface: &Ipv4Addr
) -> Result<()>
pub fn join_multicast_v4( &self, multiaddr: &Ipv4Addr, interface: &Ipv4Addr ) -> Result<()>
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.
sourcepub fn join_multicast_v6(
&self,
multiaddr: &Ipv6Addr,
interface: u32
) -> Result<()>
pub fn join_multicast_v6( &self, multiaddr: &Ipv6Addr, interface: u32 ) -> Result<()>
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).
sourcepub fn leave_multicast_v4(
&self,
multiaddr: &Ipv4Addr,
interface: &Ipv4Addr
) -> Result<()>
pub fn leave_multicast_v4( &self, multiaddr: &Ipv4Addr, interface: &Ipv4Addr ) -> Result<()>
Executes an operation of the IP_DROP_MEMBERSHIP
type.
For more information about this option, see
join_multicast_v4
.
sourcepub fn leave_multicast_v6(
&self,
multiaddr: &Ipv6Addr,
interface: u32
) -> Result<()>
pub fn leave_multicast_v6( &self, multiaddr: &Ipv6Addr, interface: u32 ) -> Result<()>
Executes an operation of the IPV6_DROP_MEMBERSHIP
type.
For more information about this option, see
join_multicast_v6
.
sourcepub fn take_error(&self) -> Result<Option<Error>>
pub fn take_error(&self) -> Result<Option<Error>>
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.
sourcepub fn try_io<F, T>(&self, f: F) -> Result<T>where
F: FnOnce() -> Result<T>,
pub fn try_io<F, T>(&self, f: F) -> Result<T>where F: FnOnce() -> Result<T>,
Execute an I/O operation ensuring that the socket receives more events
if it hits a WouldBlock
error.
Notes
This method is required to be called for all I/O operations to
ensure the user will receive events once the socket is ready again after
returning a WouldBlock
error.
Examples
use std::io;
#[cfg(unix)]
use std::os::unix::io::AsRawFd;
#[cfg(windows)]
use std::os::windows::io::AsRawSocket;
use mio::net::UdpSocket;
let address = "127.0.0.1:8080".parse().unwrap();
let dgram = UdpSocket::bind(address)?;
// Wait until the dgram is readable...
// Read from the dgram using a direct libc call, of course the
// `io::Read` implementation would be easier to use.
let mut buf = [0; 512];
let n = dgram.try_io(|| {
let buf_ptr = &mut buf as *mut _ as *mut _;
#[cfg(unix)]
let res = unsafe { libc::recv(dgram.as_raw_fd(), buf_ptr, buf.len(), 0) };
#[cfg(windows)]
let res = unsafe { libc::recvfrom(dgram.as_raw_socket() as usize, buf_ptr, buf.len() as i32, 0, std::ptr::null_mut(), std::ptr::null_mut()) };
if res != -1 {
Ok(res as usize)
} else {
// If EAGAIN or EWOULDBLOCK is set by libc::recv, the closure
// should return `WouldBlock` error.
Err(io::Error::last_os_error())
}
})?;
eprintln!("read {} bytes", n);