std/net/udp.rs
1#[cfg(all(
2 test,
3 not(any(
4 target_os = "emscripten",
5 all(target_os = "wasi", target_env = "p1"),
6 target_env = "sgx",
7 target_os = "xous",
8 target_os = "trusty",
9 target_os = "l4re",
10 ))
11))]
12mod tests;
13
14use crate::fmt;
15use crate::io::{self, ErrorKind};
16use crate::net::{Ipv4Addr, Ipv6Addr, SocketAddr, ToSocketAddrs};
17use crate::sys::{AsInner, FromInner, IntoInner, net as net_imp};
18use crate::time::Duration;
19
20/// A UDP socket.
21///
22/// After creating a `UdpSocket` by [`bind`]ing it to a socket address, data can be
23/// [sent to] and [received from] any other socket address.
24///
25/// Although UDP is a connectionless protocol, this implementation provides an interface
26/// to set an address where data should be sent and received from. After setting a remote
27/// address with [`connect`], data can be sent to and received from that address with
28/// [`send`] and [`recv`].
29///
30/// As stated in the User Datagram Protocol's specification in [IETF RFC 768], UDP is
31/// an unordered, unreliable protocol; refer to [`TcpListener`] and [`TcpStream`] for TCP
32/// primitives.
33///
34/// [`bind`]: UdpSocket::bind
35/// [`connect`]: UdpSocket::connect
36/// [IETF RFC 768]: https://tools.ietf.org/html/rfc768
37/// [`recv`]: UdpSocket::recv
38/// [received from]: UdpSocket::recv_from
39/// [`send`]: UdpSocket::send
40/// [sent to]: UdpSocket::send_to
41/// [`TcpListener`]: crate::net::TcpListener
42/// [`TcpStream`]: crate::net::TcpStream
43///
44/// # Examples
45///
46/// ```no_run
47/// use std::net::UdpSocket;
48///
49/// fn main() -> std::io::Result<()> {
50/// {
51/// let socket = UdpSocket::bind("127.0.0.1:34254")?;
52///
53/// // Receives a single datagram message on the socket. If `buf` is too small to hold
54/// // the message, it will be cut off.
55/// let mut buf = [0; 10];
56/// let (amt, src) = socket.recv_from(&mut buf)?;
57///
58/// // Redeclare `buf` as slice of the received data and send reverse data back to origin.
59/// let buf = &mut buf[..amt];
60/// buf.reverse();
61/// socket.send_to(buf, &src)?;
62/// } // the socket is closed here
63/// Ok(())
64/// }
65/// ```
66#[stable(feature = "rust1", since = "1.0.0")]
67pub struct UdpSocket(net_imp::UdpSocket);
68
69impl UdpSocket {
70 /// Creates a UDP socket from the given address.
71 ///
72 /// The address type can be any implementor of [`ToSocketAddrs`] trait. See
73 /// its documentation for concrete examples.
74 ///
75 /// If `addr` yields multiple addresses, `bind` will be attempted with
76 /// each of the addresses until one succeeds and returns the socket. If none
77 /// of the addresses succeed in creating a socket, the error returned from
78 /// the last attempt (the last address) is returned.
79 ///
80 /// # Examples
81 ///
82 /// Creates a UDP socket bound to `127.0.0.1:3400`:
83 ///
84 /// ```no_run
85 /// use std::net::UdpSocket;
86 ///
87 /// let socket = UdpSocket::bind("127.0.0.1:3400").expect("bind should succeed");
88 /// ```
89 ///
90 /// Creates a UDP socket bound to `127.0.0.1:3400`. If the socket cannot be
91 /// bound to that address, create a UDP socket bound to `127.0.0.1:3401`:
92 ///
93 /// ```no_run
94 /// use std::net::{SocketAddr, UdpSocket};
95 ///
96 /// let addrs = [
97 /// SocketAddr::from(([127, 0, 0, 1], 3400)),
98 /// SocketAddr::from(([127, 0, 0, 1], 3401)),
99 /// ];
100 /// let socket = UdpSocket::bind(&addrs[..]).expect("bind should succeed");
101 /// ```
102 ///
103 /// Creates a UDP socket bound to a port assigned by the operating system
104 /// at `127.0.0.1`.
105 ///
106 /// ```no_run
107 /// use std::net::UdpSocket;
108 ///
109 /// let socket = UdpSocket::bind("127.0.0.1:0").unwrap();
110 /// ```
111 ///
112 /// Note that `bind` declares the scope of your network connection.
113 /// You can only receive datagrams from and send datagrams to
114 /// participants in that view of the network.
115 /// For instance, binding to a loopback address as in the example
116 /// above will prevent you from sending datagrams to another device
117 /// in your local network.
118 ///
119 /// In order to limit your view of the network the least, `bind` to
120 /// [`Ipv4Addr::UNSPECIFIED`] or [`Ipv6Addr::UNSPECIFIED`].
121 #[stable(feature = "rust1", since = "1.0.0")]
122 pub fn bind<A: ToSocketAddrs>(addr: A) -> io::Result<UdpSocket> {
123 net_imp::UdpSocket::bind(addr).map(UdpSocket)
124 }
125
126 /// Receives a single datagram message on the socket. On success, returns the number
127 /// of bytes read and the origin.
128 ///
129 /// The function must be called with valid byte array `buf` of sufficient size to
130 /// hold the message bytes. If a message is too long to fit in the supplied buffer,
131 /// excess bytes may be discarded.
132 ///
133 /// Refer to the platform-specific documentation on this function; it is considered
134 /// correct for its behavior to differ from [`UdpSocket::recv`] if the underlying system
135 /// call does so.
136 ///
137 /// # Examples
138 ///
139 /// ```no_run
140 /// use std::net::UdpSocket;
141 ///
142 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("bind should succeed");
143 /// let mut buf = [0; 10];
144 /// let (number_of_bytes, src_addr) = socket.recv_from(&mut buf)
145 /// .expect("recv_from should succeed");
146 /// let filled_buf = &mut buf[..number_of_bytes];
147 /// ```
148 #[stable(feature = "rust1", since = "1.0.0")]
149 pub fn recv_from(&self, buf: &mut [u8]) -> io::Result<(usize, SocketAddr)> {
150 self.0.recv_from(buf)
151 }
152
153 /// Receives a single datagram message on the socket, without removing it from the
154 /// queue. On success, returns the number of bytes read and the origin.
155 ///
156 /// The function must be called with valid byte array `buf` of sufficient size to
157 /// hold the message bytes. If a message is too long to fit in the supplied buffer,
158 /// excess bytes may be discarded.
159 ///
160 /// Successive calls return the same data. This is accomplished by passing
161 /// `MSG_PEEK` as a flag to the underlying `recvfrom` system call.
162 ///
163 /// Do not use this function to implement busy waiting, instead use `libc::poll` to
164 /// synchronize IO events on one or more sockets.
165 ///
166 /// # Examples
167 ///
168 /// ```no_run
169 /// use std::net::UdpSocket;
170 ///
171 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("bind should succeed");
172 /// let mut buf = [0; 10];
173 /// let (number_of_bytes, src_addr) = socket.peek_from(&mut buf)
174 /// .expect("recv_from should succeed");
175 /// let filled_buf = &mut buf[..number_of_bytes];
176 /// ```
177 #[stable(feature = "peek", since = "1.18.0")]
178 pub fn peek_from(&self, buf: &mut [u8]) -> io::Result<(usize, SocketAddr)> {
179 self.0.peek_from(buf)
180 }
181
182 /// Sends data on the socket to the given address. On success, returns the
183 /// number of bytes written. Note that the operating system may refuse
184 /// buffers larger than 65507. However, partial writes are not possible
185 /// until buffer sizes above `i32::MAX`.
186 ///
187 /// Address type can be any implementor of [`ToSocketAddrs`] trait. See its
188 /// documentation for concrete examples.
189 ///
190 /// It is possible for `addr` to yield multiple addresses, but `send_to`
191 /// will only send data to the first address yielded by `addr`.
192 ///
193 /// This will return an error when the IP version of the local socket
194 /// does not match that returned from [`ToSocketAddrs`].
195 ///
196 /// See [Issue #34202] for more details.
197 ///
198 /// # Examples
199 ///
200 /// ```no_run
201 /// use std::net::UdpSocket;
202 ///
203 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("bind should succeed");
204 /// socket.send_to(&[0; 10], "127.0.0.1:4242").expect("send_to should succeed");
205 /// ```
206 ///
207 /// [Issue #34202]: https://github.com/rust-lang/rust/issues/34202
208 #[stable(feature = "rust1", since = "1.0.0")]
209 pub fn send_to<A: ToSocketAddrs>(&self, buf: &[u8], addr: A) -> io::Result<usize> {
210 match addr.to_socket_addrs()?.next() {
211 Some(addr) => self.0.send_to(buf, &addr),
212 None => Err(io::const_error!(ErrorKind::InvalidInput, "no addresses to send data to")),
213 }
214 }
215
216 /// Returns the socket address of the remote peer this socket was connected to.
217 ///
218 /// # Examples
219 ///
220 /// ```no_run
221 /// use std::net::{Ipv4Addr, SocketAddr, SocketAddrV4, UdpSocket};
222 ///
223 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("bind should succeed");
224 /// socket.connect("192.168.0.1:41203").expect("connect should succeed");
225 /// assert_eq!(socket.peer_addr().unwrap(),
226 /// SocketAddr::V4(SocketAddrV4::new(Ipv4Addr::new(192, 168, 0, 1), 41203)));
227 /// ```
228 ///
229 /// If the socket isn't connected, it will return a [`NotConnected`] error.
230 ///
231 /// [`NotConnected`]: io::ErrorKind::NotConnected
232 ///
233 /// ```no_run
234 /// use std::net::UdpSocket;
235 ///
236 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("bind should succeed");
237 /// assert_eq!(socket.peer_addr().unwrap_err().kind(),
238 /// std::io::ErrorKind::NotConnected);
239 /// ```
240 #[stable(feature = "udp_peer_addr", since = "1.40.0")]
241 pub fn peer_addr(&self) -> io::Result<SocketAddr> {
242 self.0.peer_addr()
243 }
244
245 /// Returns the socket address that this socket was created from.
246 ///
247 /// # Examples
248 ///
249 /// ```no_run
250 /// use std::net::{Ipv4Addr, SocketAddr, SocketAddrV4, UdpSocket};
251 ///
252 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("bind should succeed");
253 /// assert_eq!(socket.local_addr().unwrap(),
254 /// SocketAddr::V4(SocketAddrV4::new(Ipv4Addr::new(127, 0, 0, 1), 34254)));
255 /// ```
256 #[stable(feature = "rust1", since = "1.0.0")]
257 pub fn local_addr(&self) -> io::Result<SocketAddr> {
258 self.0.socket_addr()
259 }
260
261 /// Creates a new independently owned handle to the underlying socket.
262 ///
263 /// The returned `UdpSocket` is a reference to the same socket that this
264 /// object references. Both handles will read and write the same port, and
265 /// options set on one socket will be propagated to the other.
266 ///
267 /// # Examples
268 ///
269 /// ```no_run
270 /// use std::net::UdpSocket;
271 ///
272 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("bind should succeed");
273 /// let socket_clone = socket.try_clone().expect("try_clone should succeed");
274 /// ```
275 #[stable(feature = "rust1", since = "1.0.0")]
276 pub fn try_clone(&self) -> io::Result<UdpSocket> {
277 self.0.duplicate().map(UdpSocket)
278 }
279
280 /// Sets the read timeout to the timeout specified.
281 ///
282 /// If the value specified is [`None`], then [`read`] calls will block
283 /// indefinitely. An [`Err`] is returned if the zero [`Duration`] is
284 /// passed to this method.
285 ///
286 /// # Platform-specific behavior
287 ///
288 /// Platforms may return a different error code whenever a read times out as
289 /// a result of setting this option. For example Unix typically returns an
290 /// error of the kind [`WouldBlock`], but Windows may return [`TimedOut`].
291 ///
292 /// [`read`]: io::Read::read
293 /// [`WouldBlock`]: io::ErrorKind::WouldBlock
294 /// [`TimedOut`]: io::ErrorKind::TimedOut
295 ///
296 /// # Examples
297 ///
298 /// ```no_run
299 /// use std::net::UdpSocket;
300 ///
301 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("bind should succeed");
302 /// socket.set_read_timeout(None).expect("set_read_timeout should succeed");
303 /// ```
304 ///
305 /// An [`Err`] is returned if the zero [`Duration`] is passed to this
306 /// method:
307 ///
308 /// ```no_run
309 /// use std::io;
310 /// use std::net::UdpSocket;
311 /// use std::time::Duration;
312 ///
313 /// let socket = UdpSocket::bind("127.0.0.1:34254").unwrap();
314 /// let result = socket.set_read_timeout(Some(Duration::new(0, 0)));
315 /// let err = result.unwrap_err();
316 /// assert_eq!(err.kind(), io::ErrorKind::InvalidInput)
317 /// ```
318 #[stable(feature = "socket_timeout", since = "1.4.0")]
319 pub fn set_read_timeout(&self, dur: Option<Duration>) -> io::Result<()> {
320 self.0.set_read_timeout(dur)
321 }
322
323 /// Sets the write timeout to the timeout specified.
324 ///
325 /// If the value specified is [`None`], then [`write`] calls will block
326 /// indefinitely. An [`Err`] is returned if the zero [`Duration`] is
327 /// passed to this method.
328 ///
329 /// # Platform-specific behavior
330 ///
331 /// Platforms may return a different error code whenever a write times out
332 /// as a result of setting this option. For example Unix typically returns
333 /// an error of the kind [`WouldBlock`], but Windows may return [`TimedOut`].
334 ///
335 /// [`write`]: io::Write::write
336 /// [`WouldBlock`]: io::ErrorKind::WouldBlock
337 /// [`TimedOut`]: io::ErrorKind::TimedOut
338 ///
339 /// # Examples
340 ///
341 /// ```no_run
342 /// use std::net::UdpSocket;
343 ///
344 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("bind should succeed");
345 /// socket.set_write_timeout(None).expect("set_write_timeout should succeed");
346 /// ```
347 ///
348 /// An [`Err`] is returned if the zero [`Duration`] is passed to this
349 /// method:
350 ///
351 /// ```no_run
352 /// use std::io;
353 /// use std::net::UdpSocket;
354 /// use std::time::Duration;
355 ///
356 /// let socket = UdpSocket::bind("127.0.0.1:34254").unwrap();
357 /// let result = socket.set_write_timeout(Some(Duration::new(0, 0)));
358 /// let err = result.unwrap_err();
359 /// assert_eq!(err.kind(), io::ErrorKind::InvalidInput)
360 /// ```
361 #[stable(feature = "socket_timeout", since = "1.4.0")]
362 pub fn set_write_timeout(&self, dur: Option<Duration>) -> io::Result<()> {
363 self.0.set_write_timeout(dur)
364 }
365
366 /// Returns the read timeout of this socket.
367 ///
368 /// If the timeout is [`None`], then [`read`] calls will block indefinitely.
369 ///
370 /// [`read`]: io::Read::read
371 ///
372 /// # Examples
373 ///
374 /// ```no_run
375 /// use std::net::UdpSocket;
376 ///
377 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("bind should succeed");
378 /// socket.set_read_timeout(None).expect("set_read_timeout should succeed");
379 /// assert_eq!(socket.read_timeout().unwrap(), None);
380 /// ```
381 #[stable(feature = "socket_timeout", since = "1.4.0")]
382 pub fn read_timeout(&self) -> io::Result<Option<Duration>> {
383 self.0.read_timeout()
384 }
385
386 /// Returns the write timeout of this socket.
387 ///
388 /// If the timeout is [`None`], then [`write`] calls will block indefinitely.
389 ///
390 /// [`write`]: io::Write::write
391 ///
392 /// # Examples
393 ///
394 /// ```no_run
395 /// use std::net::UdpSocket;
396 ///
397 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("bind should succeed");
398 /// socket.set_write_timeout(None).expect("set_write_timeout should succeed");
399 /// assert_eq!(socket.write_timeout().unwrap(), None);
400 /// ```
401 #[stable(feature = "socket_timeout", since = "1.4.0")]
402 pub fn write_timeout(&self) -> io::Result<Option<Duration>> {
403 self.0.write_timeout()
404 }
405
406 /// Sets the value of the `SO_BROADCAST` option for this socket.
407 ///
408 /// When enabled, this socket is allowed to send packets to a broadcast
409 /// address.
410 ///
411 /// # Examples
412 ///
413 /// ```no_run
414 /// use std::net::UdpSocket;
415 ///
416 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("bind should succeed");
417 /// socket.set_broadcast(false).expect("set_broadcast should succeed");
418 /// ```
419 #[stable(feature = "net2_mutators", since = "1.9.0")]
420 pub fn set_broadcast(&self, broadcast: bool) -> io::Result<()> {
421 self.0.set_broadcast(broadcast)
422 }
423
424 /// Gets the value of the `SO_BROADCAST` option for this socket.
425 ///
426 /// For more information about this option, see [`UdpSocket::set_broadcast`].
427 ///
428 /// # Examples
429 ///
430 /// ```no_run
431 /// use std::net::UdpSocket;
432 ///
433 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("bind should succeed");
434 /// socket.set_broadcast(false).expect("set_broadcast should succeed");
435 /// assert_eq!(socket.broadcast().unwrap(), false);
436 /// ```
437 #[stable(feature = "net2_mutators", since = "1.9.0")]
438 pub fn broadcast(&self) -> io::Result<bool> {
439 self.0.broadcast()
440 }
441
442 /// Sets the value of the `IP_MULTICAST_LOOP` option for this socket.
443 ///
444 /// If enabled, multicast packets will be looped back to the local socket.
445 /// Note that this might not have any effect on IPv6 sockets.
446 ///
447 /// # Examples
448 ///
449 /// ```no_run
450 /// use std::net::UdpSocket;
451 ///
452 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("bind should succeed");
453 /// socket.set_multicast_loop_v4(false).expect("set_multicast_loop_v4 should succeed");
454 /// ```
455 #[stable(feature = "net2_mutators", since = "1.9.0")]
456 pub fn set_multicast_loop_v4(&self, multicast_loop_v4: bool) -> io::Result<()> {
457 self.0.set_multicast_loop_v4(multicast_loop_v4)
458 }
459
460 /// Gets the value of the `IP_MULTICAST_LOOP` option for this socket.
461 ///
462 /// For more information about this option, see [`UdpSocket::set_multicast_loop_v4`].
463 ///
464 /// # Examples
465 ///
466 /// ```no_run
467 /// use std::net::UdpSocket;
468 ///
469 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("bind should succeed");
470 /// socket.set_multicast_loop_v4(false).expect("set_multicast_loop_v4 should succeed");
471 /// assert_eq!(socket.multicast_loop_v4().unwrap(), false);
472 /// ```
473 #[stable(feature = "net2_mutators", since = "1.9.0")]
474 pub fn multicast_loop_v4(&self) -> io::Result<bool> {
475 self.0.multicast_loop_v4()
476 }
477
478 /// Sets the value of the `IP_MULTICAST_TTL` option for this socket.
479 ///
480 /// Indicates the time-to-live value of outgoing multicast packets for
481 /// this socket. The default value is 1 which means that multicast packets
482 /// don't leave the local network unless explicitly requested.
483 ///
484 /// Note that this might not have any effect on IPv6 sockets.
485 ///
486 /// # Examples
487 ///
488 /// ```no_run
489 /// use std::net::UdpSocket;
490 ///
491 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("bind should succeed");
492 /// socket.set_multicast_ttl_v4(42).expect("set_multicast_ttl_v4 should succeed");
493 /// ```
494 #[stable(feature = "net2_mutators", since = "1.9.0")]
495 pub fn set_multicast_ttl_v4(&self, multicast_ttl_v4: u32) -> io::Result<()> {
496 self.0.set_multicast_ttl_v4(multicast_ttl_v4)
497 }
498
499 /// Gets the value of the `IP_MULTICAST_TTL` option for this socket.
500 ///
501 /// For more information about this option, see [`UdpSocket::set_multicast_ttl_v4`].
502 ///
503 /// # Examples
504 ///
505 /// ```no_run
506 /// use std::net::UdpSocket;
507 ///
508 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("bind should succeed");
509 /// socket.set_multicast_ttl_v4(42).expect("set_multicast_ttl_v4 should succeed");
510 /// assert_eq!(socket.multicast_ttl_v4().unwrap(), 42);
511 /// ```
512 #[stable(feature = "net2_mutators", since = "1.9.0")]
513 pub fn multicast_ttl_v4(&self) -> io::Result<u32> {
514 self.0.multicast_ttl_v4()
515 }
516
517 /// Sets the value of the `IPV6_MULTICAST_LOOP` option for this socket.
518 ///
519 /// Controls whether this socket sees the multicast packets it sends itself.
520 /// Note that this might not have any affect on IPv4 sockets.
521 ///
522 /// # Examples
523 ///
524 /// ```no_run
525 /// use std::net::UdpSocket;
526 ///
527 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("bind should succeed");
528 /// socket.set_multicast_loop_v6(false).expect("set_multicast_loop_v6 should succeed");
529 /// ```
530 #[stable(feature = "net2_mutators", since = "1.9.0")]
531 pub fn set_multicast_loop_v6(&self, multicast_loop_v6: bool) -> io::Result<()> {
532 self.0.set_multicast_loop_v6(multicast_loop_v6)
533 }
534
535 /// Gets the value of the `IPV6_MULTICAST_LOOP` option for this socket.
536 ///
537 /// For more information about this option, see [`UdpSocket::set_multicast_loop_v6`].
538 ///
539 /// # Examples
540 ///
541 /// ```no_run
542 /// use std::net::UdpSocket;
543 ///
544 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("bind should succeed");
545 /// socket.set_multicast_loop_v6(false).expect("set_multicast_loop_v6 should succeed");
546 /// assert_eq!(socket.multicast_loop_v6().unwrap(), false);
547 /// ```
548 #[stable(feature = "net2_mutators", since = "1.9.0")]
549 pub fn multicast_loop_v6(&self) -> io::Result<bool> {
550 self.0.multicast_loop_v6()
551 }
552
553 /// Sets the value for the `IP_TTL` option on this socket.
554 ///
555 /// This value sets the time-to-live field that is used in every packet sent
556 /// from this socket.
557 ///
558 /// # Examples
559 ///
560 /// ```no_run
561 /// use std::net::UdpSocket;
562 ///
563 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("bind should succeed");
564 /// socket.set_ttl(42).expect("set_ttl should succeed");
565 /// ```
566 #[stable(feature = "net2_mutators", since = "1.9.0")]
567 pub fn set_ttl(&self, ttl: u32) -> io::Result<()> {
568 self.0.set_ttl(ttl)
569 }
570
571 /// Gets the value of the `IP_TTL` option for this socket.
572 ///
573 /// For more information about this option, see [`UdpSocket::set_ttl`].
574 ///
575 /// # Examples
576 ///
577 /// ```no_run
578 /// use std::net::UdpSocket;
579 ///
580 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("bind should succeed");
581 /// socket.set_ttl(42).expect("set_ttl should succeed");
582 /// assert_eq!(socket.ttl().unwrap(), 42);
583 /// ```
584 #[stable(feature = "net2_mutators", since = "1.9.0")]
585 pub fn ttl(&self) -> io::Result<u32> {
586 self.0.ttl()
587 }
588
589 /// Executes an operation of the `IP_ADD_MEMBERSHIP` type.
590 ///
591 /// This function specifies a new multicast group for this socket to join.
592 /// The address must be a valid multicast address, and `interface` is the
593 /// address of the local interface with which the system should join the
594 /// multicast group. If it's equal to [`UNSPECIFIED`](Ipv4Addr::UNSPECIFIED)
595 /// then an appropriate interface is chosen by the system.
596 #[stable(feature = "net2_mutators", since = "1.9.0")]
597 pub fn join_multicast_v4(&self, multiaddr: &Ipv4Addr, interface: &Ipv4Addr) -> io::Result<()> {
598 self.0.join_multicast_v4(multiaddr, interface)
599 }
600
601 /// Executes an operation of the `IPV6_ADD_MEMBERSHIP` type.
602 ///
603 /// This function specifies a new multicast group for this socket to join.
604 /// The address must be a valid multicast address, and `interface` is the
605 /// index of the interface to join/leave (or 0 to indicate any interface).
606 #[stable(feature = "net2_mutators", since = "1.9.0")]
607 pub fn join_multicast_v6(&self, multiaddr: &Ipv6Addr, interface: u32) -> io::Result<()> {
608 self.0.join_multicast_v6(multiaddr, interface)
609 }
610
611 /// Executes an operation of the `IP_DROP_MEMBERSHIP` type.
612 ///
613 /// For more information about this option, see [`UdpSocket::join_multicast_v4`].
614 #[stable(feature = "net2_mutators", since = "1.9.0")]
615 pub fn leave_multicast_v4(&self, multiaddr: &Ipv4Addr, interface: &Ipv4Addr) -> io::Result<()> {
616 self.0.leave_multicast_v4(multiaddr, interface)
617 }
618
619 /// Executes an operation of the `IPV6_DROP_MEMBERSHIP` type.
620 ///
621 /// For more information about this option, see [`UdpSocket::join_multicast_v6`].
622 #[stable(feature = "net2_mutators", since = "1.9.0")]
623 pub fn leave_multicast_v6(&self, multiaddr: &Ipv6Addr, interface: u32) -> io::Result<()> {
624 self.0.leave_multicast_v6(multiaddr, interface)
625 }
626
627 /// Gets the value of the `SO_ERROR` option on this socket.
628 ///
629 /// This will retrieve the stored error in the underlying socket, clearing
630 /// the field in the process. This can be useful for checking errors between
631 /// calls.
632 ///
633 /// # Examples
634 ///
635 /// ```no_run
636 /// use std::net::UdpSocket;
637 ///
638 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("bind should succeed");
639 /// match socket.take_error() {
640 /// Ok(Some(error)) => println!("UdpSocket error: {error:?}"),
641 /// Ok(None) => println!("No error"),
642 /// Err(error) => println!("UdpSocket.take_error failed: {error:?}"),
643 /// }
644 /// ```
645 #[stable(feature = "net2_mutators", since = "1.9.0")]
646 pub fn take_error(&self) -> io::Result<Option<io::Error>> {
647 self.0.take_error()
648 }
649
650 /// Connects this UDP socket to a remote address, allowing the `send` and
651 /// `recv` syscalls to be used to send data and also applies filters to only
652 /// receive data from the specified address.
653 ///
654 /// If `addr` yields multiple addresses, `connect` will be attempted with
655 /// each of the addresses until the underlying OS function returns no
656 /// error. Note that usually, a successful `connect` call does not specify
657 /// that there is a remote server listening on the port, rather, such an
658 /// error would only be detected after the first send. If the OS returns an
659 /// error for each of the specified addresses, the error returned from the
660 /// last connection attempt (the last address) is returned.
661 ///
662 /// # Examples
663 ///
664 /// Creates a UDP socket bound to `127.0.0.1:3400` and connect the socket to
665 /// `127.0.0.1:8080`:
666 ///
667 /// ```no_run
668 /// use std::net::UdpSocket;
669 ///
670 /// let socket = UdpSocket::bind("127.0.0.1:3400").expect("bind should succeed");
671 /// socket.connect("127.0.0.1:8080").expect("connect should succeed");
672 /// ```
673 ///
674 /// Unlike in the TCP case, passing an array of addresses to the `connect`
675 /// function of a UDP socket is not a useful thing to do: The OS will be
676 /// unable to determine whether something is listening on the remote
677 /// address without the application sending data.
678 ///
679 /// If your first `connect` is to a loopback address, subsequent
680 /// `connect`s to non-loopback addresses might fail, depending
681 /// on the platform.
682 #[stable(feature = "net2_mutators", since = "1.9.0")]
683 pub fn connect<A: ToSocketAddrs>(&self, addr: A) -> io::Result<()> {
684 self.0.connect(addr)
685 }
686
687 /// Sends data on the socket to the remote address to which it is connected.
688 /// On success, returns the number of bytes written. Note that the operating
689 /// system may refuse buffers larger than 65507. However, partial writes are
690 /// not possible until buffer sizes above `i32::MAX`.
691 ///
692 /// [`UdpSocket::connect`] will connect this socket to a remote address. This
693 /// method will fail if the socket is not connected.
694 ///
695 /// # Examples
696 ///
697 /// ```no_run
698 /// use std::net::UdpSocket;
699 ///
700 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("bind should succeed");
701 /// socket.connect("127.0.0.1:8080").expect("connect should succeed");
702 /// socket.send(&[0, 1, 2]).expect("send should succeed");
703 /// ```
704 #[stable(feature = "net2_mutators", since = "1.9.0")]
705 pub fn send(&self, buf: &[u8]) -> io::Result<usize> {
706 self.0.send(buf)
707 }
708
709 /// Receives a single datagram message on the socket from the remote address to
710 /// which it is connected. On success, returns the number of bytes read.
711 ///
712 /// The function must be called with valid byte array `buf` of sufficient size to
713 /// hold the message bytes. If a message is too long to fit in the supplied buffer,
714 /// excess bytes may be discarded.
715 ///
716 /// [`UdpSocket::connect`] will connect this socket to a remote address. This
717 /// method will fail if the socket is not connected.
718 ///
719 /// Refer to the platform-specific documentation on this function; it is considered
720 /// correct for its behavior to differ from [`UdpSocket::recv_from`] if the underlying
721 /// system call does so.
722 ///
723 /// # Examples
724 ///
725 /// ```no_run
726 /// use std::net::UdpSocket;
727 ///
728 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("bind should succeed");
729 /// socket.connect("127.0.0.1:8080").expect("connect should succeed");
730 /// let mut buf = [0; 10];
731 /// match socket.recv(&mut buf) {
732 /// Ok(received) => println!("received {received} bytes {:?}", &buf[..received]),
733 /// Err(e) => println!("recv function failed: {e:?}"),
734 /// }
735 /// ```
736 #[stable(feature = "net2_mutators", since = "1.9.0")]
737 pub fn recv(&self, buf: &mut [u8]) -> io::Result<usize> {
738 self.0.recv(buf)
739 }
740
741 /// Receives single datagram on the socket from the remote address to which it is
742 /// connected, without removing the message from input queue. On success, returns
743 /// the number of bytes peeked.
744 ///
745 /// The function must be called with valid byte array `buf` of sufficient size to
746 /// hold the message bytes. If a message is too long to fit in the supplied buffer,
747 /// excess bytes may be discarded.
748 ///
749 /// Successive calls return the same data. This is accomplished by passing
750 /// `MSG_PEEK` as a flag to the underlying `recv` system call.
751 ///
752 /// Do not use this function to implement busy waiting, instead use `libc::poll` to
753 /// synchronize IO events on one or more sockets.
754 ///
755 /// [`UdpSocket::connect`] will connect this socket to a remote address. This
756 /// method will fail if the socket is not connected.
757 ///
758 /// # Errors
759 ///
760 /// This method will fail if the socket is not connected. The `connect` method
761 /// will connect this socket to a remote address.
762 ///
763 /// # Examples
764 ///
765 /// ```no_run
766 /// use std::net::UdpSocket;
767 ///
768 /// let socket = UdpSocket::bind("127.0.0.1:34254").expect("bind should succeed");
769 /// socket.connect("127.0.0.1:8080").expect("connect should succeed");
770 /// let mut buf = [0; 10];
771 /// match socket.peek(&mut buf) {
772 /// Ok(received) => println!("received {received} bytes"),
773 /// Err(e) => println!("peek function failed: {e:?}"),
774 /// }
775 /// ```
776 #[stable(feature = "peek", since = "1.18.0")]
777 pub fn peek(&self, buf: &mut [u8]) -> io::Result<usize> {
778 self.0.peek(buf)
779 }
780
781 /// Moves this UDP socket into or out of nonblocking mode.
782 ///
783 /// This will result in `recv`, `recv_from`, `send`, and `send_to` system
784 /// operations becoming nonblocking, i.e., immediately returning from their
785 /// calls. If the IO operation is successful, `Ok` is returned and no
786 /// further action is required. If the IO operation could not be completed
787 /// and needs to be retried, an error with kind
788 /// [`io::ErrorKind::WouldBlock`] is returned.
789 ///
790 /// On most Unix platforms, calling this method corresponds to calling `ioctl`
791 /// `FIONBIO`. On Windows, calling this method corresponds to calling
792 /// `ioctlsocket` `FIONBIO`.
793 ///
794 /// # Examples
795 ///
796 /// Creates a UDP socket bound to `127.0.0.1:7878` and read bytes in
797 /// nonblocking mode:
798 ///
799 /// ```no_run
800 /// use std::io;
801 /// use std::net::UdpSocket;
802 ///
803 /// let socket = UdpSocket::bind("127.0.0.1:7878").unwrap();
804 /// socket.set_nonblocking(true).unwrap();
805 ///
806 /// # fn wait_for_fd() { unimplemented!() }
807 /// let mut buf = [0; 10];
808 /// let (num_bytes_read, _) = loop {
809 /// match socket.recv_from(&mut buf) {
810 /// Ok(n) => break n,
811 /// Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
812 /// // wait until network socket is ready, typically implemented
813 /// // via platform-specific APIs such as epoll or IOCP
814 /// wait_for_fd();
815 /// }
816 /// Err(e) => panic!("encountered IO error: {e}"),
817 /// }
818 /// };
819 /// println!("bytes: {:?}", &buf[..num_bytes_read]);
820 /// ```
821 #[stable(feature = "net2_mutators", since = "1.9.0")]
822 pub fn set_nonblocking(&self, nonblocking: bool) -> io::Result<()> {
823 self.0.set_nonblocking(nonblocking)
824 }
825}
826
827// In addition to the `impl`s here, `UdpSocket` also has `impl`s for
828// `AsFd`/`From<OwnedFd>`/`Into<OwnedFd>` and
829// `AsRawFd`/`IntoRawFd`/`FromRawFd`, on Unix and WASI, and
830// `AsSocket`/`From<OwnedSocket>`/`Into<OwnedSocket>` and
831// `AsRawSocket`/`IntoRawSocket`/`FromRawSocket` on Windows.
832
833impl AsInner<net_imp::UdpSocket> for UdpSocket {
834 #[inline]
835 fn as_inner(&self) -> &net_imp::UdpSocket {
836 &self.0
837 }
838}
839
840impl FromInner<net_imp::UdpSocket> for UdpSocket {
841 fn from_inner(inner: net_imp::UdpSocket) -> UdpSocket {
842 UdpSocket(inner)
843 }
844}
845
846impl IntoInner<net_imp::UdpSocket> for UdpSocket {
847 fn into_inner(self) -> net_imp::UdpSocket {
848 self.0
849 }
850}
851
852#[stable(feature = "rust1", since = "1.0.0")]
853impl fmt::Debug for UdpSocket {
854 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
855 self.0.fmt(f)
856 }
857}
