1 #[cfg(all(test, not(any(target_os = "emscripten", target_env = "sgx"))))]
5 use crate::io::{self, Error, ErrorKind};
6 use crate::net::{Ipv4Addr, Ipv6Addr, SocketAddr, ToSocketAddrs};
7 use crate::sys_common::net as net_imp;
8 use crate::sys_common::{AsInner, FromInner, IntoInner};
9 use crate::time::Duration;
13 /// After creating a `UdpSocket` by [`bind`]ing it to a socket address, data can be
14 /// [sent to] and [received from] any other socket address.
16 /// Although UDP is a connectionless protocol, this implementation provides an interface
17 /// to set an address where data should be sent and received from. After setting a remote
18 /// address with [`connect`], data can be sent to and received from that address with
19 /// [`send`] and [`recv`].
21 /// As stated in the User Datagram Protocol's specification in [IETF RFC 768], UDP is
22 /// an unordered, unreliable protocol; refer to [`TcpListener`] and [`TcpStream`] for TCP
25 /// [`bind`]: UdpSocket::bind
26 /// [`connect`]: UdpSocket::connect
27 /// [IETF RFC 768]: https://tools.ietf.org/html/rfc768
28 /// [`recv`]: UdpSocket::recv
29 /// [received from]: UdpSocket::recv_from
30 /// [`send`]: UdpSocket::send
31 /// [sent to]: UdpSocket::send_to
32 /// [`TcpListener`]: crate::net::TcpListener
33 /// [`TcpStream`]: crate::net::TcpStream
38 /// use std::net::UdpSocket;
40 /// fn main() -> std::io::Result<()> {
42 /// let mut socket = UdpSocket::bind("127.0.0.1:34254")?;
44 /// // Receives a single datagram message on the socket. If `buf` is too small to hold
45 /// // the message, it will be cut off.
46 /// let mut buf = [0; 10];
47 /// let (amt, src) = socket.recv_from(&mut buf)?;
49 /// // Redeclare `buf` as slice of the received data and send reverse data back to origin.
50 /// let buf = &mut buf[..amt];
52 /// socket.send_to(buf, &src)?;
53 /// } // the socket is closed here
57 #[stable(feature = "rust1", since = "1.0.0")]
58 pub struct UdpSocket(net_imp::UdpSocket);
61 /// Creates a UDP socket from the given address.
63 /// The address type can be any implementor of [`ToSocketAddrs`] trait. See
64 /// its documentation for concrete examples.
66 /// If `addr` yields multiple addresses, `bind` will be attempted with
67 /// each of the addresses until one succeeds and returns the socket. If none
68 /// of the addresses succeed in creating a socket, the error returned from
69 /// the last attempt (the last address) is returned.
73 /// Creates a UDP socket bound to `127.0.0.1:3400`:
76 /// use std::net::UdpSocket;
78 /// let socket = UdpSocket::bind("127.0.0.1:3400").expect("couldn't bind to address");
81 /// Creates a UDP socket bound to `127.0.0.1:3400`. If the socket cannot be
82 /// bound to that address, create a UDP socket bound to `127.0.0.1:3401`:
85 /// use std::net::{SocketAddr, UdpSocket};
88 /// SocketAddr::from(([127, 0, 0, 1], 3400)),
89 /// SocketAddr::from(([127, 0, 0, 1], 3401)),
91 /// let socket = UdpSocket::bind(&addrs[..]).expect("couldn't bind to address");
93 #[stable(feature = "rust1", since = "1.0.0")]
94 pub fn bind<A: ToSocketAddrs>(addr: A) -> io::Result<UdpSocket> {
95 super::each_addr(addr, net_imp::UdpSocket::bind).map(UdpSocket)
98 /// Receives a single datagram message on the socket. On success, returns the number
99 /// of bytes read and the origin.
101 /// The function must be called with valid byte array `buf` of sufficient size to
102 /// hold the message bytes. If a message is too long to fit in the supplied buffer,
103 /// excess bytes may be discarded.
108 /// use std::net::UdpSocket;
110 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
111 /// let mut buf = [0; 10];
112 /// let (number_of_bytes, src_addr) = socket.recv_from(&mut buf)
113 /// .expect("Didn't receive data");
114 /// let filled_buf = &mut buf[..number_of_bytes];
116 #[stable(feature = "rust1", since = "1.0.0")]
117 pub fn recv_from(&self, buf: &mut [u8]) -> io::Result<(usize, SocketAddr)> {
118 self.0.recv_from(buf)
121 /// Receives a single datagram message on the socket, without removing it from the
122 /// queue. On success, returns the number of bytes read and the origin.
124 /// The function must be called with valid byte array `buf` of sufficient size to
125 /// hold the message bytes. If a message is too long to fit in the supplied buffer,
126 /// excess bytes may be discarded.
128 /// Successive calls return the same data. This is accomplished by passing
129 /// `MSG_PEEK` as a flag to the underlying `recvfrom` system call.
131 /// Do not use this function to implement busy waiting, instead use `libc::poll` to
132 /// synchronize IO events on one or more sockets.
137 /// use std::net::UdpSocket;
139 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
140 /// let mut buf = [0; 10];
141 /// let (number_of_bytes, src_addr) = socket.peek_from(&mut buf)
142 /// .expect("Didn't receive data");
143 /// let filled_buf = &mut buf[..number_of_bytes];
145 #[stable(feature = "peek", since = "1.18.0")]
146 pub fn peek_from(&self, buf: &mut [u8]) -> io::Result<(usize, SocketAddr)> {
147 self.0.peek_from(buf)
150 /// Sends data on the socket to the given address. On success, returns the
151 /// number of bytes written.
153 /// Address type can be any implementor of [`ToSocketAddrs`] trait. See its
154 /// documentation for concrete examples.
156 /// It is possible for `addr` to yield multiple addresses, but `send_to`
157 /// will only send data to the first address yielded by `addr`.
159 /// This will return an error when the IP version of the local socket
160 /// does not match that returned from [`ToSocketAddrs`].
162 /// See issue #34202 for more details.
167 /// use std::net::UdpSocket;
169 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
170 /// socket.send_to(&[0; 10], "127.0.0.1:4242").expect("couldn't send data");
172 #[stable(feature = "rust1", since = "1.0.0")]
173 pub fn send_to<A: ToSocketAddrs>(&self, buf: &[u8], addr: A) -> io::Result<usize> {
174 match addr.to_socket_addrs()?.next() {
175 Some(addr) => self.0.send_to(buf, &addr),
176 None => Err(Error::new_const(ErrorKind::InvalidInput, &"no addresses to send data to")),
180 /// Returns the socket address of the remote peer this socket was connected to.
185 /// use std::net::{Ipv4Addr, SocketAddr, SocketAddrV4, UdpSocket};
187 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
188 /// socket.connect("192.168.0.1:41203").expect("couldn't connect to address");
189 /// assert_eq!(socket.peer_addr().unwrap(),
190 /// SocketAddr::V4(SocketAddrV4::new(Ipv4Addr::new(192, 168, 0, 1), 41203)));
193 /// If the socket isn't connected, it will return a [`NotConnected`] error.
195 /// [`NotConnected`]: io::ErrorKind::NotConnected
198 /// use std::net::UdpSocket;
200 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
201 /// assert_eq!(socket.peer_addr().unwrap_err().kind(),
202 /// std::io::ErrorKind::NotConnected);
204 #[stable(feature = "udp_peer_addr", since = "1.40.0")]
205 pub fn peer_addr(&self) -> io::Result<SocketAddr> {
209 /// Returns the socket address that this socket was created from.
214 /// use std::net::{Ipv4Addr, SocketAddr, SocketAddrV4, UdpSocket};
216 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
217 /// assert_eq!(socket.local_addr().unwrap(),
218 /// SocketAddr::V4(SocketAddrV4::new(Ipv4Addr::new(127, 0, 0, 1), 34254)));
220 #[stable(feature = "rust1", since = "1.0.0")]
221 pub fn local_addr(&self) -> io::Result<SocketAddr> {
225 /// Creates a new independently owned handle to the underlying socket.
227 /// The returned `UdpSocket` is a reference to the same socket that this
228 /// object references. Both handles will read and write the same port, and
229 /// options set on one socket will be propagated to the other.
234 /// use std::net::UdpSocket;
236 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
237 /// let socket_clone = socket.try_clone().expect("couldn't clone the socket");
239 #[stable(feature = "rust1", since = "1.0.0")]
240 pub fn try_clone(&self) -> io::Result<UdpSocket> {
241 self.0.duplicate().map(UdpSocket)
244 /// Sets the read timeout to the timeout specified.
246 /// If the value specified is [`None`], then [`read`] calls will block
247 /// indefinitely. An [`Err`] is returned if the zero [`Duration`] is
248 /// passed to this method.
250 /// # Platform-specific behavior
252 /// Platforms may return a different error code whenever a read times out as
253 /// a result of setting this option. For example Unix typically returns an
254 /// error of the kind [`WouldBlock`], but Windows may return [`TimedOut`].
256 /// [`read`]: io::Read::read
257 /// [`WouldBlock`]: io::ErrorKind::WouldBlock
258 /// [`TimedOut`]: io::ErrorKind::TimedOut
263 /// use std::net::UdpSocket;
265 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
266 /// socket.set_read_timeout(None).expect("set_read_timeout call failed");
269 /// An [`Err`] is returned if the zero [`Duration`] is passed to this
274 /// use std::net::UdpSocket;
275 /// use std::time::Duration;
277 /// let socket = UdpSocket::bind("127.0.0.1:34254").unwrap();
278 /// let result = socket.set_read_timeout(Some(Duration::new(0, 0)));
279 /// let err = result.unwrap_err();
280 /// assert_eq!(err.kind(), io::ErrorKind::InvalidInput)
282 #[stable(feature = "socket_timeout", since = "1.4.0")]
283 pub fn set_read_timeout(&self, dur: Option<Duration>) -> io::Result<()> {
284 self.0.set_read_timeout(dur)
287 /// Sets the write timeout to the timeout specified.
289 /// If the value specified is [`None`], then [`write`] calls will block
290 /// indefinitely. An [`Err`] is returned if the zero [`Duration`] is
291 /// passed to this method.
293 /// # Platform-specific behavior
295 /// Platforms may return a different error code whenever a write times out
296 /// as a result of setting this option. For example Unix typically returns
297 /// an error of the kind [`WouldBlock`], but Windows may return [`TimedOut`].
299 /// [`write`]: io::Write::write
300 /// [`WouldBlock`]: io::ErrorKind::WouldBlock
301 /// [`TimedOut`]: io::ErrorKind::TimedOut
306 /// use std::net::UdpSocket;
308 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
309 /// socket.set_write_timeout(None).expect("set_write_timeout call failed");
312 /// An [`Err`] is returned if the zero [`Duration`] is passed to this
317 /// use std::net::UdpSocket;
318 /// use std::time::Duration;
320 /// let socket = UdpSocket::bind("127.0.0.1:34254").unwrap();
321 /// let result = socket.set_write_timeout(Some(Duration::new(0, 0)));
322 /// let err = result.unwrap_err();
323 /// assert_eq!(err.kind(), io::ErrorKind::InvalidInput)
325 #[stable(feature = "socket_timeout", since = "1.4.0")]
326 pub fn set_write_timeout(&self, dur: Option<Duration>) -> io::Result<()> {
327 self.0.set_write_timeout(dur)
330 /// Returns the read timeout of this socket.
332 /// If the timeout is [`None`], then [`read`] calls will block indefinitely.
334 /// [`read`]: io::Read::read
339 /// use std::net::UdpSocket;
341 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
342 /// socket.set_read_timeout(None).expect("set_read_timeout call failed");
343 /// assert_eq!(socket.read_timeout().unwrap(), None);
345 #[stable(feature = "socket_timeout", since = "1.4.0")]
346 pub fn read_timeout(&self) -> io::Result<Option<Duration>> {
347 self.0.read_timeout()
350 /// Returns the write timeout of this socket.
352 /// If the timeout is [`None`], then [`write`] calls will block indefinitely.
354 /// [`write`]: io::Write::write
359 /// use std::net::UdpSocket;
361 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
362 /// socket.set_write_timeout(None).expect("set_write_timeout call failed");
363 /// assert_eq!(socket.write_timeout().unwrap(), None);
365 #[stable(feature = "socket_timeout", since = "1.4.0")]
366 pub fn write_timeout(&self) -> io::Result<Option<Duration>> {
367 self.0.write_timeout()
370 /// Sets the value of the `SO_BROADCAST` option for this socket.
372 /// When enabled, this socket is allowed to send packets to a broadcast
378 /// use std::net::UdpSocket;
380 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
381 /// socket.set_broadcast(false).expect("set_broadcast call failed");
383 #[stable(feature = "net2_mutators", since = "1.9.0")]
384 pub fn set_broadcast(&self, broadcast: bool) -> io::Result<()> {
385 self.0.set_broadcast(broadcast)
388 /// Gets the value of the `SO_BROADCAST` option for this socket.
390 /// For more information about this option, see [`UdpSocket::set_broadcast`].
395 /// use std::net::UdpSocket;
397 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
398 /// socket.set_broadcast(false).expect("set_broadcast call failed");
399 /// assert_eq!(socket.broadcast().unwrap(), false);
401 #[stable(feature = "net2_mutators", since = "1.9.0")]
402 pub fn broadcast(&self) -> io::Result<bool> {
406 /// Sets the value of the `IP_MULTICAST_LOOP` option for this socket.
408 /// If enabled, multicast packets will be looped back to the local socket.
409 /// Note that this may not have any effect on IPv6 sockets.
414 /// use std::net::UdpSocket;
416 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
417 /// socket.set_multicast_loop_v4(false).expect("set_multicast_loop_v4 call failed");
419 #[stable(feature = "net2_mutators", since = "1.9.0")]
420 pub fn set_multicast_loop_v4(&self, multicast_loop_v4: bool) -> io::Result<()> {
421 self.0.set_multicast_loop_v4(multicast_loop_v4)
424 /// Gets the value of the `IP_MULTICAST_LOOP` option for this socket.
426 /// For more information about this option, see [`UdpSocket::set_multicast_loop_v4`].
431 /// use std::net::UdpSocket;
433 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
434 /// socket.set_multicast_loop_v4(false).expect("set_multicast_loop_v4 call failed");
435 /// assert_eq!(socket.multicast_loop_v4().unwrap(), false);
437 #[stable(feature = "net2_mutators", since = "1.9.0")]
438 pub fn multicast_loop_v4(&self) -> io::Result<bool> {
439 self.0.multicast_loop_v4()
442 /// Sets the value of the `IP_MULTICAST_TTL` option for this socket.
444 /// Indicates the time-to-live value of outgoing multicast packets for
445 /// this socket. The default value is 1 which means that multicast packets
446 /// don't leave the local network unless explicitly requested.
448 /// Note that this may not have any effect on IPv6 sockets.
453 /// use std::net::UdpSocket;
455 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
456 /// socket.set_multicast_ttl_v4(42).expect("set_multicast_ttl_v4 call failed");
458 #[stable(feature = "net2_mutators", since = "1.9.0")]
459 pub fn set_multicast_ttl_v4(&self, multicast_ttl_v4: u32) -> io::Result<()> {
460 self.0.set_multicast_ttl_v4(multicast_ttl_v4)
463 /// Gets the value of the `IP_MULTICAST_TTL` option for this socket.
465 /// For more information about this option, see [`UdpSocket::set_multicast_ttl_v4`].
470 /// use std::net::UdpSocket;
472 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
473 /// socket.set_multicast_ttl_v4(42).expect("set_multicast_ttl_v4 call failed");
474 /// assert_eq!(socket.multicast_ttl_v4().unwrap(), 42);
476 #[stable(feature = "net2_mutators", since = "1.9.0")]
477 pub fn multicast_ttl_v4(&self) -> io::Result<u32> {
478 self.0.multicast_ttl_v4()
481 /// Sets the value of the `IPV6_MULTICAST_LOOP` option for this socket.
483 /// Controls whether this socket sees the multicast packets it sends itself.
484 /// Note that this may not have any affect on IPv4 sockets.
489 /// use std::net::UdpSocket;
491 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
492 /// socket.set_multicast_loop_v6(false).expect("set_multicast_loop_v6 call failed");
494 #[stable(feature = "net2_mutators", since = "1.9.0")]
495 pub fn set_multicast_loop_v6(&self, multicast_loop_v6: bool) -> io::Result<()> {
496 self.0.set_multicast_loop_v6(multicast_loop_v6)
499 /// Gets the value of the `IPV6_MULTICAST_LOOP` option for this socket.
501 /// For more information about this option, see [`UdpSocket::set_multicast_loop_v6`].
506 /// use std::net::UdpSocket;
508 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
509 /// socket.set_multicast_loop_v6(false).expect("set_multicast_loop_v6 call failed");
510 /// assert_eq!(socket.multicast_loop_v6().unwrap(), false);
512 #[stable(feature = "net2_mutators", since = "1.9.0")]
513 pub fn multicast_loop_v6(&self) -> io::Result<bool> {
514 self.0.multicast_loop_v6()
517 /// Sets the value for the `IP_TTL` option on this socket.
519 /// This value sets the time-to-live field that is used in every packet sent
520 /// from this socket.
525 /// use std::net::UdpSocket;
527 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
528 /// socket.set_ttl(42).expect("set_ttl call failed");
530 #[stable(feature = "net2_mutators", since = "1.9.0")]
531 pub fn set_ttl(&self, ttl: u32) -> io::Result<()> {
535 /// Gets the value of the `IP_TTL` option for this socket.
537 /// For more information about this option, see [`UdpSocket::set_ttl`].
542 /// use std::net::UdpSocket;
544 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
545 /// socket.set_ttl(42).expect("set_ttl call failed");
546 /// assert_eq!(socket.ttl().unwrap(), 42);
548 #[stable(feature = "net2_mutators", since = "1.9.0")]
549 pub fn ttl(&self) -> io::Result<u32> {
553 /// Executes an operation of the `IP_ADD_MEMBERSHIP` type.
555 /// This function specifies a new multicast group for this socket to join.
556 /// The address must be a valid multicast address, and `interface` is the
557 /// address of the local interface with which the system should join the
558 /// multicast group. If it's equal to `INADDR_ANY` then an appropriate
559 /// interface is chosen by the system.
560 #[stable(feature = "net2_mutators", since = "1.9.0")]
561 pub fn join_multicast_v4(&self, multiaddr: &Ipv4Addr, interface: &Ipv4Addr) -> io::Result<()> {
562 self.0.join_multicast_v4(multiaddr, interface)
565 /// Executes an operation of the `IPV6_ADD_MEMBERSHIP` type.
567 /// This function specifies a new multicast group for this socket to join.
568 /// The address must be a valid multicast address, and `interface` is the
569 /// index of the interface to join/leave (or 0 to indicate any interface).
570 #[stable(feature = "net2_mutators", since = "1.9.0")]
571 pub fn join_multicast_v6(&self, multiaddr: &Ipv6Addr, interface: u32) -> io::Result<()> {
572 self.0.join_multicast_v6(multiaddr, interface)
575 /// Executes an operation of the `IP_DROP_MEMBERSHIP` type.
577 /// For more information about this option, see [`UdpSocket::join_multicast_v4`].
578 #[stable(feature = "net2_mutators", since = "1.9.0")]
579 pub fn leave_multicast_v4(&self, multiaddr: &Ipv4Addr, interface: &Ipv4Addr) -> io::Result<()> {
580 self.0.leave_multicast_v4(multiaddr, interface)
583 /// Executes an operation of the `IPV6_DROP_MEMBERSHIP` type.
585 /// For more information about this option, see [`UdpSocket::join_multicast_v6`].
586 #[stable(feature = "net2_mutators", since = "1.9.0")]
587 pub fn leave_multicast_v6(&self, multiaddr: &Ipv6Addr, interface: u32) -> io::Result<()> {
588 self.0.leave_multicast_v6(multiaddr, interface)
591 /// Gets the value of the `SO_ERROR` option on this socket.
593 /// This will retrieve the stored error in the underlying socket, clearing
594 /// the field in the process. This can be useful for checking errors between
600 /// use std::net::UdpSocket;
602 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
603 /// match socket.take_error() {
604 /// Ok(Some(error)) => println!("UdpSocket error: {:?}", error),
605 /// Ok(None) => println!("No error"),
606 /// Err(error) => println!("UdpSocket.take_error failed: {:?}", error),
609 #[stable(feature = "net2_mutators", since = "1.9.0")]
610 pub fn take_error(&self) -> io::Result<Option<io::Error>> {
614 /// Connects this UDP socket to a remote address, allowing the `send` and
615 /// `recv` syscalls to be used to send data and also applies filters to only
616 /// receive data from the specified address.
618 /// If `addr` yields multiple addresses, `connect` will be attempted with
619 /// each of the addresses until the underlying OS function returns no
620 /// error. Note that usually, a successful `connect` call does not specify
621 /// that there is a remote server listening on the port, rather, such an
622 /// error would only be detected after the first send. If the OS returns an
623 /// error for each of the specified addresses, the error returned from the
624 /// last connection attempt (the last address) is returned.
628 /// Creates a UDP socket bound to `127.0.0.1:3400` and connect the socket to
629 /// `127.0.0.1:8080`:
632 /// use std::net::UdpSocket;
634 /// let socket = UdpSocket::bind("127.0.0.1:3400").expect("couldn't bind to address");
635 /// socket.connect("127.0.0.1:8080").expect("connect function failed");
638 /// Unlike in the TCP case, passing an array of addresses to the `connect`
639 /// function of a UDP socket is not a useful thing to do: The OS will be
640 /// unable to determine whether something is listening on the remote
641 /// address without the application sending data.
642 #[stable(feature = "net2_mutators", since = "1.9.0")]
643 pub fn connect<A: ToSocketAddrs>(&self, addr: A) -> io::Result<()> {
644 super::each_addr(addr, |addr| self.0.connect(addr))
647 /// Sends data on the socket to the remote address to which it is connected.
649 /// [`UdpSocket::connect`] will connect this socket to a remote address. This
650 /// method will fail if the socket is not connected.
655 /// use std::net::UdpSocket;
657 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
658 /// socket.connect("127.0.0.1:8080").expect("connect function failed");
659 /// socket.send(&[0, 1, 2]).expect("couldn't send message");
661 #[stable(feature = "net2_mutators", since = "1.9.0")]
662 pub fn send(&self, buf: &[u8]) -> io::Result<usize> {
666 /// Receives a single datagram message on the socket from the remote address to
667 /// which it is connected. On success, returns the number of bytes read.
669 /// The function must be called with valid byte array `buf` of sufficient size to
670 /// hold the message bytes. If a message is too long to fit in the supplied buffer,
671 /// excess bytes may be discarded.
673 /// [`UdpSocket::connect`] will connect this socket to a remote address. This
674 /// method will fail if the socket is not connected.
679 /// use std::net::UdpSocket;
681 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
682 /// socket.connect("127.0.0.1:8080").expect("connect function failed");
683 /// let mut buf = [0; 10];
684 /// match socket.recv(&mut buf) {
685 /// Ok(received) => println!("received {} bytes {:?}", received, &buf[..received]),
686 /// Err(e) => println!("recv function failed: {:?}", e),
689 #[stable(feature = "net2_mutators", since = "1.9.0")]
690 pub fn recv(&self, buf: &mut [u8]) -> io::Result<usize> {
694 /// Receives single datagram on the socket from the remote address to which it is
695 /// connected, without removing the message from input queue. On success, returns
696 /// the number of bytes peeked.
698 /// The function must be called with valid byte array `buf` of sufficient size to
699 /// hold the message bytes. If a message is too long to fit in the supplied buffer,
700 /// excess bytes may be discarded.
702 /// Successive calls return the same data. This is accomplished by passing
703 /// `MSG_PEEK` as a flag to the underlying `recv` system call.
705 /// Do not use this function to implement busy waiting, instead use `libc::poll` to
706 /// synchronize IO events on one or more sockets.
708 /// [`UdpSocket::connect`] will connect this socket to a remote address. This
709 /// method will fail if the socket is not connected.
713 /// This method will fail if the socket is not connected. The `connect` method
714 /// will connect this socket to a remote address.
719 /// use std::net::UdpSocket;
721 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
722 /// socket.connect("127.0.0.1:8080").expect("connect function failed");
723 /// let mut buf = [0; 10];
724 /// match socket.peek(&mut buf) {
725 /// Ok(received) => println!("received {} bytes", received),
726 /// Err(e) => println!("peek function failed: {:?}", e),
729 #[stable(feature = "peek", since = "1.18.0")]
730 pub fn peek(&self, buf: &mut [u8]) -> io::Result<usize> {
734 /// Moves this UDP socket into or out of nonblocking mode.
736 /// This will result in `recv`, `recv_from`, `send`, and `send_to`
737 /// operations becoming nonblocking, i.e., immediately returning from their
738 /// calls. If the IO operation is successful, `Ok` is returned and no
739 /// further action is required. If the IO operation could not be completed
740 /// and needs to be retried, an error with kind
741 /// [`io::ErrorKind::WouldBlock`] is returned.
743 /// On Unix platforms, calling this method corresponds to calling `fcntl`
744 /// `FIONBIO`. On Windows calling this method corresponds to calling
745 /// `ioctlsocket` `FIONBIO`.
749 /// Creates a UDP socket bound to `127.0.0.1:7878` and read bytes in
750 /// nonblocking mode:
754 /// use std::net::UdpSocket;
756 /// let socket = UdpSocket::bind("127.0.0.1:7878").unwrap();
757 /// socket.set_nonblocking(true).unwrap();
759 /// # fn wait_for_fd() { unimplemented!() }
760 /// let mut buf = [0; 10];
761 /// let (num_bytes_read, _) = loop {
762 /// match socket.recv_from(&mut buf) {
763 /// Ok(n) => break n,
764 /// Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
765 /// // wait until network socket is ready, typically implemented
766 /// // via platform-specific APIs such as epoll or IOCP
769 /// Err(e) => panic!("encountered IO error: {}", e),
772 /// println!("bytes: {:?}", &buf[..num_bytes_read]);
774 #[stable(feature = "net2_mutators", since = "1.9.0")]
775 pub fn set_nonblocking(&self, nonblocking: bool) -> io::Result<()> {
776 self.0.set_nonblocking(nonblocking)
780 impl AsInner<net_imp::UdpSocket> for UdpSocket {
781 fn as_inner(&self) -> &net_imp::UdpSocket {
786 impl FromInner<net_imp::UdpSocket> for UdpSocket {
787 fn from_inner(inner: net_imp::UdpSocket) -> UdpSocket {
792 impl IntoInner<net_imp::UdpSocket> for UdpSocket {
793 fn into_inner(self) -> net_imp::UdpSocket {
798 #[stable(feature = "rust1", since = "1.0.0")]
799 impl fmt::Debug for UdpSocket {
800 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {