1 #[cfg(all(test, not(any(target_os = "emscripten", target_env = "sgx"))))]
5 use crate::io::{self, 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 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");
173 /// [Issue #34202]: https://github.com/rust-lang/rust/issues/34202
174 #[stable(feature = "rust1", since = "1.0.0")]
175 pub fn send_to<A: ToSocketAddrs>(&self, buf: &[u8], addr: A) -> io::Result<usize> {
176 match addr.to_socket_addrs()?.next() {
177 Some(addr) => self.0.send_to(buf, &addr),
179 Err(io::const_io_error!(ErrorKind::InvalidInput, "no addresses to send data to"))
184 /// Returns the socket address of the remote peer this socket was connected to.
189 /// use std::net::{Ipv4Addr, SocketAddr, SocketAddrV4, UdpSocket};
191 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
192 /// socket.connect("192.168.0.1:41203").expect("couldn't connect to address");
193 /// assert_eq!(socket.peer_addr().unwrap(),
194 /// SocketAddr::V4(SocketAddrV4::new(Ipv4Addr::new(192, 168, 0, 1), 41203)));
197 /// If the socket isn't connected, it will return a [`NotConnected`] error.
199 /// [`NotConnected`]: io::ErrorKind::NotConnected
202 /// use std::net::UdpSocket;
204 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
205 /// assert_eq!(socket.peer_addr().unwrap_err().kind(),
206 /// std::io::ErrorKind::NotConnected);
208 #[stable(feature = "udp_peer_addr", since = "1.40.0")]
209 pub fn peer_addr(&self) -> io::Result<SocketAddr> {
213 /// Returns the socket address that this socket was created from.
218 /// use std::net::{Ipv4Addr, SocketAddr, SocketAddrV4, UdpSocket};
220 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
221 /// assert_eq!(socket.local_addr().unwrap(),
222 /// SocketAddr::V4(SocketAddrV4::new(Ipv4Addr::new(127, 0, 0, 1), 34254)));
224 #[stable(feature = "rust1", since = "1.0.0")]
225 pub fn local_addr(&self) -> io::Result<SocketAddr> {
229 /// Creates a new independently owned handle to the underlying socket.
231 /// The returned `UdpSocket` is a reference to the same socket that this
232 /// object references. Both handles will read and write the same port, and
233 /// options set on one socket will be propagated to the other.
238 /// use std::net::UdpSocket;
240 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
241 /// let socket_clone = socket.try_clone().expect("couldn't clone the socket");
243 #[stable(feature = "rust1", since = "1.0.0")]
244 pub fn try_clone(&self) -> io::Result<UdpSocket> {
245 self.0.duplicate().map(UdpSocket)
248 /// Sets the read timeout to the timeout specified.
250 /// If the value specified is [`None`], then [`read`] calls will block
251 /// indefinitely. An [`Err`] is returned if the zero [`Duration`] is
252 /// passed to this method.
254 /// # Platform-specific behavior
256 /// Platforms may return a different error code whenever a read times out as
257 /// a result of setting this option. For example Unix typically returns an
258 /// error of the kind [`WouldBlock`], but Windows may return [`TimedOut`].
260 /// [`read`]: io::Read::read
261 /// [`WouldBlock`]: io::ErrorKind::WouldBlock
262 /// [`TimedOut`]: io::ErrorKind::TimedOut
267 /// use std::net::UdpSocket;
269 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
270 /// socket.set_read_timeout(None).expect("set_read_timeout call failed");
273 /// An [`Err`] is returned if the zero [`Duration`] is passed to this
278 /// use std::net::UdpSocket;
279 /// use std::time::Duration;
281 /// let socket = UdpSocket::bind("127.0.0.1:34254").unwrap();
282 /// let result = socket.set_read_timeout(Some(Duration::new(0, 0)));
283 /// let err = result.unwrap_err();
284 /// assert_eq!(err.kind(), io::ErrorKind::InvalidInput)
286 #[stable(feature = "socket_timeout", since = "1.4.0")]
287 pub fn set_read_timeout(&self, dur: Option<Duration>) -> io::Result<()> {
288 self.0.set_read_timeout(dur)
291 /// Sets the write timeout to the timeout specified.
293 /// If the value specified is [`None`], then [`write`] calls will block
294 /// indefinitely. An [`Err`] is returned if the zero [`Duration`] is
295 /// passed to this method.
297 /// # Platform-specific behavior
299 /// Platforms may return a different error code whenever a write times out
300 /// as a result of setting this option. For example Unix typically returns
301 /// an error of the kind [`WouldBlock`], but Windows may return [`TimedOut`].
303 /// [`write`]: io::Write::write
304 /// [`WouldBlock`]: io::ErrorKind::WouldBlock
305 /// [`TimedOut`]: io::ErrorKind::TimedOut
310 /// use std::net::UdpSocket;
312 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
313 /// socket.set_write_timeout(None).expect("set_write_timeout call failed");
316 /// An [`Err`] is returned if the zero [`Duration`] is passed to this
321 /// use std::net::UdpSocket;
322 /// use std::time::Duration;
324 /// let socket = UdpSocket::bind("127.0.0.1:34254").unwrap();
325 /// let result = socket.set_write_timeout(Some(Duration::new(0, 0)));
326 /// let err = result.unwrap_err();
327 /// assert_eq!(err.kind(), io::ErrorKind::InvalidInput)
329 #[stable(feature = "socket_timeout", since = "1.4.0")]
330 pub fn set_write_timeout(&self, dur: Option<Duration>) -> io::Result<()> {
331 self.0.set_write_timeout(dur)
334 /// Returns the read timeout of this socket.
336 /// If the timeout is [`None`], then [`read`] calls will block indefinitely.
338 /// [`read`]: io::Read::read
343 /// use std::net::UdpSocket;
345 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
346 /// socket.set_read_timeout(None).expect("set_read_timeout call failed");
347 /// assert_eq!(socket.read_timeout().unwrap(), None);
349 #[stable(feature = "socket_timeout", since = "1.4.0")]
350 pub fn read_timeout(&self) -> io::Result<Option<Duration>> {
351 self.0.read_timeout()
354 /// Returns the write timeout of this socket.
356 /// If the timeout is [`None`], then [`write`] calls will block indefinitely.
358 /// [`write`]: io::Write::write
363 /// use std::net::UdpSocket;
365 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
366 /// socket.set_write_timeout(None).expect("set_write_timeout call failed");
367 /// assert_eq!(socket.write_timeout().unwrap(), None);
369 #[stable(feature = "socket_timeout", since = "1.4.0")]
370 pub fn write_timeout(&self) -> io::Result<Option<Duration>> {
371 self.0.write_timeout()
374 /// Sets the value of the `SO_BROADCAST` option for this socket.
376 /// When enabled, this socket is allowed to send packets to a broadcast
382 /// use std::net::UdpSocket;
384 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
385 /// socket.set_broadcast(false).expect("set_broadcast call failed");
387 #[stable(feature = "net2_mutators", since = "1.9.0")]
388 pub fn set_broadcast(&self, broadcast: bool) -> io::Result<()> {
389 self.0.set_broadcast(broadcast)
392 /// Gets the value of the `SO_BROADCAST` option for this socket.
394 /// For more information about this option, see [`UdpSocket::set_broadcast`].
399 /// use std::net::UdpSocket;
401 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
402 /// socket.set_broadcast(false).expect("set_broadcast call failed");
403 /// assert_eq!(socket.broadcast().unwrap(), false);
405 #[stable(feature = "net2_mutators", since = "1.9.0")]
406 pub fn broadcast(&self) -> io::Result<bool> {
410 /// Sets the value of the `IP_MULTICAST_LOOP` option for this socket.
412 /// If enabled, multicast packets will be looped back to the local socket.
413 /// Note that this might not have any effect on IPv6 sockets.
418 /// use std::net::UdpSocket;
420 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
421 /// socket.set_multicast_loop_v4(false).expect("set_multicast_loop_v4 call failed");
423 #[stable(feature = "net2_mutators", since = "1.9.0")]
424 pub fn set_multicast_loop_v4(&self, multicast_loop_v4: bool) -> io::Result<()> {
425 self.0.set_multicast_loop_v4(multicast_loop_v4)
428 /// Gets the value of the `IP_MULTICAST_LOOP` option for this socket.
430 /// For more information about this option, see [`UdpSocket::set_multicast_loop_v4`].
435 /// use std::net::UdpSocket;
437 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
438 /// socket.set_multicast_loop_v4(false).expect("set_multicast_loop_v4 call failed");
439 /// assert_eq!(socket.multicast_loop_v4().unwrap(), false);
441 #[stable(feature = "net2_mutators", since = "1.9.0")]
442 pub fn multicast_loop_v4(&self) -> io::Result<bool> {
443 self.0.multicast_loop_v4()
446 /// Sets the value of the `IP_MULTICAST_TTL` option for this socket.
448 /// Indicates the time-to-live value of outgoing multicast packets for
449 /// this socket. The default value is 1 which means that multicast packets
450 /// don't leave the local network unless explicitly requested.
452 /// Note that this might not have any effect on IPv6 sockets.
457 /// use std::net::UdpSocket;
459 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
460 /// socket.set_multicast_ttl_v4(42).expect("set_multicast_ttl_v4 call failed");
462 #[stable(feature = "net2_mutators", since = "1.9.0")]
463 pub fn set_multicast_ttl_v4(&self, multicast_ttl_v4: u32) -> io::Result<()> {
464 self.0.set_multicast_ttl_v4(multicast_ttl_v4)
467 /// Gets the value of the `IP_MULTICAST_TTL` option for this socket.
469 /// For more information about this option, see [`UdpSocket::set_multicast_ttl_v4`].
474 /// use std::net::UdpSocket;
476 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
477 /// socket.set_multicast_ttl_v4(42).expect("set_multicast_ttl_v4 call failed");
478 /// assert_eq!(socket.multicast_ttl_v4().unwrap(), 42);
480 #[stable(feature = "net2_mutators", since = "1.9.0")]
481 pub fn multicast_ttl_v4(&self) -> io::Result<u32> {
482 self.0.multicast_ttl_v4()
485 /// Sets the value of the `IPV6_MULTICAST_LOOP` option for this socket.
487 /// Controls whether this socket sees the multicast packets it sends itself.
488 /// Note that this might not have any affect on IPv4 sockets.
493 /// use std::net::UdpSocket;
495 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
496 /// socket.set_multicast_loop_v6(false).expect("set_multicast_loop_v6 call failed");
498 #[stable(feature = "net2_mutators", since = "1.9.0")]
499 pub fn set_multicast_loop_v6(&self, multicast_loop_v6: bool) -> io::Result<()> {
500 self.0.set_multicast_loop_v6(multicast_loop_v6)
503 /// Gets the value of the `IPV6_MULTICAST_LOOP` option for this socket.
505 /// For more information about this option, see [`UdpSocket::set_multicast_loop_v6`].
510 /// use std::net::UdpSocket;
512 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
513 /// socket.set_multicast_loop_v6(false).expect("set_multicast_loop_v6 call failed");
514 /// assert_eq!(socket.multicast_loop_v6().unwrap(), false);
516 #[stable(feature = "net2_mutators", since = "1.9.0")]
517 pub fn multicast_loop_v6(&self) -> io::Result<bool> {
518 self.0.multicast_loop_v6()
521 /// Sets the value for the `IP_TTL` option on this socket.
523 /// This value sets the time-to-live field that is used in every packet sent
524 /// from this socket.
529 /// use std::net::UdpSocket;
531 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
532 /// socket.set_ttl(42).expect("set_ttl call failed");
534 #[stable(feature = "net2_mutators", since = "1.9.0")]
535 pub fn set_ttl(&self, ttl: u32) -> io::Result<()> {
539 /// Gets the value of the `IP_TTL` option for this socket.
541 /// For more information about this option, see [`UdpSocket::set_ttl`].
546 /// use std::net::UdpSocket;
548 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
549 /// socket.set_ttl(42).expect("set_ttl call failed");
550 /// assert_eq!(socket.ttl().unwrap(), 42);
552 #[stable(feature = "net2_mutators", since = "1.9.0")]
553 pub fn ttl(&self) -> io::Result<u32> {
557 /// Executes an operation of the `IP_ADD_MEMBERSHIP` type.
559 /// This function specifies a new multicast group for this socket to join.
560 /// The address must be a valid multicast address, and `interface` is the
561 /// address of the local interface with which the system should join the
562 /// multicast group. If it's equal to `INADDR_ANY` then an appropriate
563 /// interface is chosen by the system.
564 #[stable(feature = "net2_mutators", since = "1.9.0")]
565 pub fn join_multicast_v4(&self, multiaddr: &Ipv4Addr, interface: &Ipv4Addr) -> io::Result<()> {
566 self.0.join_multicast_v4(multiaddr, interface)
569 /// Executes an operation of the `IPV6_ADD_MEMBERSHIP` type.
571 /// This function specifies a new multicast group for this socket to join.
572 /// The address must be a valid multicast address, and `interface` is the
573 /// index of the interface to join/leave (or 0 to indicate any interface).
574 #[stable(feature = "net2_mutators", since = "1.9.0")]
575 pub fn join_multicast_v6(&self, multiaddr: &Ipv6Addr, interface: u32) -> io::Result<()> {
576 self.0.join_multicast_v6(multiaddr, interface)
579 /// Executes an operation of the `IP_DROP_MEMBERSHIP` type.
581 /// For more information about this option, see [`UdpSocket::join_multicast_v4`].
582 #[stable(feature = "net2_mutators", since = "1.9.0")]
583 pub fn leave_multicast_v4(&self, multiaddr: &Ipv4Addr, interface: &Ipv4Addr) -> io::Result<()> {
584 self.0.leave_multicast_v4(multiaddr, interface)
587 /// Executes an operation of the `IPV6_DROP_MEMBERSHIP` type.
589 /// For more information about this option, see [`UdpSocket::join_multicast_v6`].
590 #[stable(feature = "net2_mutators", since = "1.9.0")]
591 pub fn leave_multicast_v6(&self, multiaddr: &Ipv6Addr, interface: u32) -> io::Result<()> {
592 self.0.leave_multicast_v6(multiaddr, interface)
595 /// Gets the value of the `SO_ERROR` option on this socket.
597 /// This will retrieve the stored error in the underlying socket, clearing
598 /// the field in the process. This can be useful for checking errors between
604 /// use std::net::UdpSocket;
606 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
607 /// match socket.take_error() {
608 /// Ok(Some(error)) => println!("UdpSocket error: {error:?}"),
609 /// Ok(None) => println!("No error"),
610 /// Err(error) => println!("UdpSocket.take_error failed: {error:?}"),
613 #[stable(feature = "net2_mutators", since = "1.9.0")]
614 pub fn take_error(&self) -> io::Result<Option<io::Error>> {
618 /// Connects this UDP socket to a remote address, allowing the `send` and
619 /// `recv` syscalls to be used to send data and also applies filters to only
620 /// receive data from the specified address.
622 /// If `addr` yields multiple addresses, `connect` will be attempted with
623 /// each of the addresses until the underlying OS function returns no
624 /// error. Note that usually, a successful `connect` call does not specify
625 /// that there is a remote server listening on the port, rather, such an
626 /// error would only be detected after the first send. If the OS returns an
627 /// error for each of the specified addresses, the error returned from the
628 /// last connection attempt (the last address) is returned.
632 /// Creates a UDP socket bound to `127.0.0.1:3400` and connect the socket to
633 /// `127.0.0.1:8080`:
636 /// use std::net::UdpSocket;
638 /// let socket = UdpSocket::bind("127.0.0.1:3400").expect("couldn't bind to address");
639 /// socket.connect("127.0.0.1:8080").expect("connect function failed");
642 /// Unlike in the TCP case, passing an array of addresses to the `connect`
643 /// function of a UDP socket is not a useful thing to do: The OS will be
644 /// unable to determine whether something is listening on the remote
645 /// address without the application sending data.
646 #[stable(feature = "net2_mutators", since = "1.9.0")]
647 pub fn connect<A: ToSocketAddrs>(&self, addr: A) -> io::Result<()> {
648 super::each_addr(addr, |addr| self.0.connect(addr))
651 /// Sends data on the socket to the remote address to which it is connected.
653 /// [`UdpSocket::connect`] will connect this socket to a remote address. This
654 /// method will fail if the socket is not connected.
659 /// use std::net::UdpSocket;
661 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
662 /// socket.connect("127.0.0.1:8080").expect("connect function failed");
663 /// socket.send(&[0, 1, 2]).expect("couldn't send message");
665 #[stable(feature = "net2_mutators", since = "1.9.0")]
666 pub fn send(&self, buf: &[u8]) -> io::Result<usize> {
670 /// Receives a single datagram message on the socket from the remote address to
671 /// which it is connected. On success, returns the number of bytes read.
673 /// The function must be called with valid byte array `buf` of sufficient size to
674 /// hold the message bytes. If a message is too long to fit in the supplied buffer,
675 /// excess bytes may be discarded.
677 /// [`UdpSocket::connect`] will connect this socket to a remote address. This
678 /// method will fail if the socket is not connected.
683 /// use std::net::UdpSocket;
685 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
686 /// socket.connect("127.0.0.1:8080").expect("connect function failed");
687 /// let mut buf = [0; 10];
688 /// match socket.recv(&mut buf) {
689 /// Ok(received) => println!("received {received} bytes {:?}", &buf[..received]),
690 /// Err(e) => println!("recv function failed: {e:?}"),
693 #[stable(feature = "net2_mutators", since = "1.9.0")]
694 pub fn recv(&self, buf: &mut [u8]) -> io::Result<usize> {
698 /// Receives single datagram on the socket from the remote address to which it is
699 /// connected, without removing the message from input queue. On success, returns
700 /// the number of bytes peeked.
702 /// The function must be called with valid byte array `buf` of sufficient size to
703 /// hold the message bytes. If a message is too long to fit in the supplied buffer,
704 /// excess bytes may be discarded.
706 /// Successive calls return the same data. This is accomplished by passing
707 /// `MSG_PEEK` as a flag to the underlying `recv` system call.
709 /// Do not use this function to implement busy waiting, instead use `libc::poll` to
710 /// synchronize IO events on one or more sockets.
712 /// [`UdpSocket::connect`] will connect this socket to a remote address. This
713 /// method will fail if the socket is not connected.
717 /// This method will fail if the socket is not connected. The `connect` method
718 /// will connect this socket to a remote address.
723 /// use std::net::UdpSocket;
725 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
726 /// socket.connect("127.0.0.1:8080").expect("connect function failed");
727 /// let mut buf = [0; 10];
728 /// match socket.peek(&mut buf) {
729 /// Ok(received) => println!("received {received} bytes"),
730 /// Err(e) => println!("peek function failed: {e:?}"),
733 #[stable(feature = "peek", since = "1.18.0")]
734 pub fn peek(&self, buf: &mut [u8]) -> io::Result<usize> {
738 /// Moves this UDP socket into or out of nonblocking mode.
740 /// This will result in `recv`, `recv_from`, `send`, and `send_to`
741 /// operations becoming nonblocking, i.e., immediately returning from their
742 /// calls. If the IO operation is successful, `Ok` is returned and no
743 /// further action is required. If the IO operation could not be completed
744 /// and needs to be retried, an error with kind
745 /// [`io::ErrorKind::WouldBlock`] is returned.
747 /// On Unix platforms, calling this method corresponds to calling `fcntl`
748 /// `FIONBIO`. On Windows calling this method corresponds to calling
749 /// `ioctlsocket` `FIONBIO`.
753 /// Creates a UDP socket bound to `127.0.0.1:7878` and read bytes in
754 /// nonblocking mode:
758 /// use std::net::UdpSocket;
760 /// let socket = UdpSocket::bind("127.0.0.1:7878").unwrap();
761 /// socket.set_nonblocking(true).unwrap();
763 /// # fn wait_for_fd() { unimplemented!() }
764 /// let mut buf = [0; 10];
765 /// let (num_bytes_read, _) = loop {
766 /// match socket.recv_from(&mut buf) {
767 /// Ok(n) => break n,
768 /// Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
769 /// // wait until network socket is ready, typically implemented
770 /// // via platform-specific APIs such as epoll or IOCP
773 /// Err(e) => panic!("encountered IO error: {e}"),
776 /// println!("bytes: {:?}", &buf[..num_bytes_read]);
778 #[stable(feature = "net2_mutators", since = "1.9.0")]
779 pub fn set_nonblocking(&self, nonblocking: bool) -> io::Result<()> {
780 self.0.set_nonblocking(nonblocking)
784 // In addition to the `impl`s here, `UdpSocket` also has `impl`s for
785 // `AsFd`/`From<OwnedFd>`/`Into<OwnedFd>` and
786 // `AsRawFd`/`IntoRawFd`/`FromRawFd`, on Unix and WASI, and
787 // `AsSocket`/`From<OwnedSocket>`/`Into<OwnedSocket>` and
788 // `AsRawSocket`/`IntoRawSocket`/`FromRawSocket` on Windows.
790 impl AsInner<net_imp::UdpSocket> for UdpSocket {
791 fn as_inner(&self) -> &net_imp::UdpSocket {
796 impl FromInner<net_imp::UdpSocket> for UdpSocket {
797 fn from_inner(inner: net_imp::UdpSocket) -> UdpSocket {
802 impl IntoInner<net_imp::UdpSocket> for UdpSocket {
803 fn into_inner(self) -> net_imp::UdpSocket {
808 #[stable(feature = "rust1", since = "1.0.0")]
809 impl fmt::Debug for UdpSocket {
810 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {