TLA Line data Source code
1 : //
2 : // Copyright (c) 2026 Steve Gerbino
3 : // Copyright (c) 2026 Michael Vandeberg
4 : //
5 : // Distributed under the Boost Software License, Version 1.0. (See accompanying
6 : // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
7 : //
8 : // Official repository: https://github.com/cppalliance/corosio
9 : //
10 :
11 : #ifndef BOOST_COROSIO_UDP_SOCKET_HPP
12 : #define BOOST_COROSIO_UDP_SOCKET_HPP
13 :
14 : #include <boost/corosio/detail/config.hpp>
15 : #include <boost/corosio/detail/platform.hpp>
16 : #include <boost/corosio/detail/except.hpp>
17 : #include <boost/corosio/detail/native_handle.hpp>
18 : #include <boost/corosio/detail/op_base.hpp>
19 : #include <boost/corosio/io/io_object.hpp>
20 : #include <boost/capy/io_result.hpp>
21 : #include <boost/corosio/detail/buffer_param.hpp>
22 : #include <boost/corosio/endpoint.hpp>
23 : #include <boost/corosio/message_flags.hpp>
24 : #include <boost/corosio/shutdown_type.hpp>
25 : #include <boost/corosio/udp.hpp>
26 : #include <boost/corosio/wait_type.hpp>
27 : #include <boost/capy/ex/executor_ref.hpp>
28 : #include <boost/capy/ex/execution_context.hpp>
29 : #include <boost/capy/ex/io_env.hpp>
30 : #include <boost/capy/concept/executor.hpp>
31 :
32 : #include <system_error>
33 :
34 : #include <concepts>
35 : #include <coroutine>
36 : #include <cstddef>
37 : #include <stop_token>
38 : #include <type_traits>
39 :
40 : namespace boost::corosio {
41 :
42 : /** An asynchronous UDP socket for coroutine I/O.
43 :
44 : This class provides asynchronous UDP datagram operations that
45 : return awaitable types. Each operation participates in the affine
46 : awaitable protocol, ensuring coroutines resume on the correct
47 : executor.
48 :
49 : Supports two modes of operation:
50 :
51 : **Connectionless mode**: each `send_to` specifies a destination
52 : endpoint, and each `recv_from` captures the source endpoint.
53 : The socket must be opened (and optionally bound) before I/O.
54 :
55 : **Connected mode**: call `connect()` to set a default peer,
56 : then use `send()`/`recv()` without endpoint arguments.
57 : The kernel filters incoming datagrams to those from the
58 : connected peer.
59 :
60 : @par Thread Safety
61 : Distinct objects: Safe.@n
62 : Shared objects: Unsafe. A socket must not have concurrent
63 : operations of the same type (e.g., two simultaneous recv_from).
64 : One send_to and one recv_from may be in flight simultaneously.
65 :
66 : @par Example
67 : @par !example udp_socket
68 : */
69 : class BOOST_COROSIO_DECL udp_socket : public io_object
70 : {
71 : public:
72 : using shutdown_type = corosio::shutdown_type;
73 : using enum corosio::shutdown_type;
74 :
75 : /** Define backend hooks for UDP socket operations.
76 :
77 : Platform backends (epoll, kqueue, select) derive from
78 : this to implement datagram I/O and option management.
79 : */
80 : struct implementation : io_object::implementation
81 : {
82 : /** Initiate an asynchronous send_to operation.
83 :
84 : @param h Coroutine handle to resume on completion.
85 : @param ex Executor for dispatching the completion.
86 : @param buf The buffer data to send.
87 : @param dest The destination endpoint.
88 : @param flags Platform message flags (e.g. `MSG_DONTWAIT`).
89 : @param token Stop token for cancellation.
90 : @param ec Output error code.
91 : @param bytes_out Output bytes transferred.
92 :
93 : @return Coroutine handle to resume immediately.
94 : */
95 : virtual std::coroutine_handle<> send_to(
96 : std::coroutine_handle<> h,
97 : capy::executor_ref ex,
98 : buffer_param buf,
99 : endpoint dest,
100 : int flags,
101 : std::stop_token token,
102 : std::error_code* ec,
103 : std::size_t* bytes_out) = 0;
104 :
105 : /** Initiate an asynchronous recv_from operation.
106 :
107 : @param h Coroutine handle to resume on completion.
108 : @param ex Executor for dispatching the completion.
109 : @param buf The buffer to receive into.
110 : @param source Output endpoint for the sender's address.
111 : @param flags Platform message flags (e.g. `MSG_PEEK`).
112 : @param token Stop token for cancellation.
113 : @param ec Output error code.
114 : @param bytes_out Output bytes transferred.
115 :
116 : @return Coroutine handle to resume immediately.
117 : */
118 : virtual std::coroutine_handle<> recv_from(
119 : std::coroutine_handle<> h,
120 : capy::executor_ref ex,
121 : buffer_param buf,
122 : endpoint* source,
123 : int flags,
124 : std::stop_token token,
125 : std::error_code* ec,
126 : std::size_t* bytes_out) = 0;
127 :
128 : /// Return the platform socket descriptor.
129 : virtual native_handle_type native_handle() const noexcept = 0;
130 :
131 : /** Release ownership of the native socket handle.
132 :
133 : Deregisters the socket from the backend and cancels
134 : pending operations without closing the descriptor. The
135 : caller takes ownership.
136 :
137 : @return The native handle.
138 : */
139 : virtual native_handle_type release_socket() noexcept = 0;
140 :
141 : /** Request cancellation of pending asynchronous operations.
142 :
143 : All outstanding operations complete with operation_canceled
144 : error. Check `ec == cond::canceled` for portable comparison.
145 : */
146 : virtual void cancel() noexcept = 0;
147 :
148 : /// Shut down the socket in one or both directions.
149 : virtual std::error_code shutdown(shutdown_type what) noexcept = 0;
150 :
151 : /** Set a socket option.
152 :
153 : @param level The protocol level (e.g. `SOL_SOCKET`).
154 : @param optname The option name.
155 : @param data Pointer to the option value.
156 : @param size Size of the option value in bytes.
157 : @return Error code on failure, empty on success.
158 : */
159 : virtual std::error_code set_option(
160 : int level,
161 : int optname,
162 : void const* data,
163 : std::size_t size) noexcept = 0;
164 :
165 : /** Get a socket option.
166 :
167 : @param level The protocol level (e.g. `SOL_SOCKET`).
168 : @param optname The option name.
169 : @param data Pointer to receive the option value.
170 : @param size On entry, the size of the buffer. On exit,
171 : the size of the option value.
172 : @return Error code on failure, empty on success.
173 : */
174 : virtual std::error_code
175 : get_option(int level, int optname, void* data, std::size_t* size)
176 : const noexcept = 0;
177 :
178 : /// Return the cached local endpoint.
179 : virtual endpoint local_endpoint() const noexcept = 0;
180 :
181 : /// Return the cached remote endpoint (connected mode).
182 : virtual endpoint remote_endpoint() const noexcept = 0;
183 :
184 : /** Initiate an asynchronous connect to set the default peer.
185 :
186 : @param h Coroutine handle to resume on completion.
187 : @param ex Executor for dispatching the completion.
188 : @param ep The remote endpoint to connect to.
189 : @param token Stop token for cancellation.
190 : @param ec Output error code.
191 :
192 : @return Coroutine handle to resume immediately.
193 : */
194 : virtual std::coroutine_handle<> connect(
195 : std::coroutine_handle<> h,
196 : capy::executor_ref ex,
197 : endpoint ep,
198 : std::stop_token token,
199 : std::error_code* ec) = 0;
200 :
201 : /** Initiate an asynchronous connected send operation.
202 :
203 : @param h Coroutine handle to resume on completion.
204 : @param ex Executor for dispatching the completion.
205 : @param buf The buffer data to send.
206 : @param flags Platform message flags (e.g. `MSG_DONTWAIT`).
207 : @param token Stop token for cancellation.
208 : @param ec Output error code.
209 : @param bytes_out Output bytes transferred.
210 :
211 : @return Coroutine handle to resume immediately.
212 : */
213 : virtual std::coroutine_handle<> send(
214 : std::coroutine_handle<> h,
215 : capy::executor_ref ex,
216 : buffer_param buf,
217 : int flags,
218 : std::stop_token token,
219 : std::error_code* ec,
220 : std::size_t* bytes_out) = 0;
221 :
222 : /** Initiate an asynchronous connected recv operation.
223 :
224 : @param h Coroutine handle to resume on completion.
225 : @param ex Executor for dispatching the completion.
226 : @param buf The buffer to receive into.
227 : @param flags Platform message flags (e.g. `MSG_PEEK`).
228 : @param token Stop token for cancellation.
229 : @param ec Output error code.
230 : @param bytes_out Output bytes transferred.
231 :
232 : @return Coroutine handle to resume immediately.
233 : */
234 : virtual std::coroutine_handle<> recv(
235 : std::coroutine_handle<> h,
236 : capy::executor_ref ex,
237 : buffer_param buf,
238 : int flags,
239 : std::stop_token token,
240 : std::error_code* ec,
241 : std::size_t* bytes_out) = 0;
242 :
243 : /** Initiate an asynchronous wait for socket readiness.
244 :
245 : Completes when the socket becomes ready for the
246 : specified direction, or an error condition is
247 : reported. No bytes are transferred.
248 :
249 : @param h Coroutine handle to resume on completion.
250 : @param ex Executor for dispatching the completion.
251 : @param w The direction to wait on.
252 : @param token Stop token for cancellation.
253 : @param ec Output error code.
254 :
255 : @return Coroutine handle to resume immediately.
256 : */
257 : virtual std::coroutine_handle<> wait(
258 : std::coroutine_handle<> h,
259 : capy::executor_ref ex,
260 : wait_type w,
261 : std::stop_token token,
262 : std::error_code* ec) = 0;
263 : };
264 :
265 : /** Represent the awaitable returned by @ref send_to.
266 :
267 : Captures the destination endpoint and buffer, then dispatches
268 : to the backend implementation on suspension.
269 : */
270 : struct send_to_awaitable
271 : : detail::bytes_op_base<send_to_awaitable>
272 : {
273 : udp_socket& s_;
274 : buffer_param buf_;
275 : endpoint dest_;
276 : int flags_;
277 :
278 HIT 71 : send_to_awaitable(
279 : udp_socket& s, buffer_param buf,
280 : endpoint dest, int flags = 0) noexcept
281 71 : : s_(s), buf_(buf), dest_(dest), flags_(flags) {}
282 :
283 69 : std::coroutine_handle<> dispatch(
284 : std::coroutine_handle<> h, capy::executor_ref ex) const
285 : {
286 138 : return s_.get().send_to(
287 138 : h, ex, buf_, dest_, flags_, token_, &ec_, &bytes_);
288 : }
289 : };
290 :
291 : /** Represent the awaitable returned by @ref recv_from.
292 :
293 : Captures the source endpoint reference and buffer, then
294 : dispatches to the backend implementation on suspension.
295 : */
296 : struct recv_from_awaitable
297 : : detail::bytes_op_base<recv_from_awaitable>
298 : {
299 : udp_socket& s_;
300 : buffer_param buf_;
301 : endpoint& source_;
302 : int flags_;
303 :
304 91 : recv_from_awaitable(
305 : udp_socket& s, buffer_param buf,
306 : endpoint& source, int flags = 0) noexcept
307 91 : : s_(s), buf_(buf), source_(source), flags_(flags) {}
308 :
309 89 : std::coroutine_handle<> dispatch(
310 : std::coroutine_handle<> h, capy::executor_ref ex) const
311 : {
312 178 : return s_.get().recv_from(
313 178 : h, ex, buf_, &source_, flags_, token_, &ec_, &bytes_);
314 : }
315 : };
316 :
317 : /// Represent the awaitable returned by @ref connect.
318 : struct connect_awaitable
319 : : detail::void_op_base<connect_awaitable>
320 : {
321 : udp_socket& s_;
322 : endpoint endpoint_;
323 :
324 40 : connect_awaitable(udp_socket& s, endpoint ep) noexcept
325 40 : : s_(s), endpoint_(ep) {}
326 :
327 40 : std::coroutine_handle<> dispatch(
328 : std::coroutine_handle<> h, capy::executor_ref ex) const
329 : {
330 40 : return s_.get().connect(h, ex, endpoint_, token_, &ec_);
331 : }
332 : };
333 :
334 : /// Represent the awaitable returned by @ref wait.
335 : struct wait_awaitable
336 : : detail::void_op_base<wait_awaitable>
337 : {
338 : udp_socket& s_;
339 : wait_type w_;
340 :
341 30 : wait_awaitable(udp_socket& s, wait_type w) noexcept
342 30 : : s_(s), w_(w) {}
343 :
344 30 : std::coroutine_handle<> dispatch(
345 : std::coroutine_handle<> h, capy::executor_ref ex) const
346 : {
347 30 : return s_.get().wait(h, ex, w_, token_, &ec_);
348 : }
349 : };
350 :
351 : /// Represent the awaitable returned by @ref send.
352 : struct send_awaitable
353 : : detail::bytes_op_base<send_awaitable>
354 : {
355 : udp_socket& s_;
356 : buffer_param buf_;
357 : int flags_;
358 :
359 26 : send_awaitable(
360 : udp_socket& s, buffer_param buf,
361 : int flags = 0) noexcept
362 26 : : s_(s), buf_(buf), flags_(flags) {}
363 :
364 24 : std::coroutine_handle<> dispatch(
365 : std::coroutine_handle<> h, capy::executor_ref ex) const
366 : {
367 48 : return s_.get().send(
368 48 : h, ex, buf_, flags_, token_, &ec_, &bytes_);
369 : }
370 : };
371 :
372 : /// Represent the awaitable returned by @ref recv.
373 : struct recv_awaitable
374 : : detail::bytes_op_base<recv_awaitable>
375 : {
376 : udp_socket& s_;
377 : buffer_param buf_;
378 : int flags_;
379 :
380 61 : recv_awaitable(
381 : udp_socket& s, buffer_param buf,
382 : int flags = 0) noexcept
383 61 : : s_(s), buf_(buf), flags_(flags) {}
384 :
385 59 : std::coroutine_handle<> dispatch(
386 : std::coroutine_handle<> h, capy::executor_ref ex) const
387 : {
388 118 : return s_.get().recv(
389 118 : h, ex, buf_, flags_, token_, &ec_, &bytes_);
390 : }
391 : };
392 :
393 : public:
394 : /** Destructor.
395 :
396 : Closes the socket if open, cancelling any pending operations.
397 : */
398 : ~udp_socket() override;
399 :
400 : /** Construct a socket from an execution context.
401 :
402 : @param ctx The execution context that will own this socket.
403 : */
404 : explicit udp_socket(capy::execution_context& ctx);
405 :
406 : /** Construct a socket from an executor.
407 :
408 : The socket is associated with the executor's context.
409 :
410 : @param ex The executor whose context will own the socket.
411 : */
412 : template<class Ex>
413 : requires(!std::same_as<std::remove_cvref_t<Ex>, udp_socket>) &&
414 : capy::Executor<Ex>
415 : explicit udp_socket(Ex const& ex) : udp_socket(ex.context())
416 : {
417 : }
418 :
419 : /** Move constructor.
420 :
421 : Transfers ownership of the socket resources.
422 :
423 : @param other The socket to move from.
424 : */
425 4 : udp_socket(udp_socket&& other) noexcept : io_object(std::move(other)) {}
426 :
427 : /** Move assignment operator.
428 :
429 : Closes any existing socket and transfers ownership.
430 :
431 : @param other The socket to move from.
432 : @return Reference to this socket.
433 : */
434 2 : udp_socket& operator=(udp_socket&& other) noexcept
435 : {
436 2 : if (this != &other)
437 : {
438 2 : close();
439 2 : h_ = std::move(other.h_);
440 : }
441 2 : return *this;
442 : }
443 :
444 : udp_socket(udp_socket const&) = delete;
445 : udp_socket& operator=(udp_socket const&) = delete;
446 :
447 : /** Open the socket.
448 :
449 : Creates a UDP socket and associates it with the platform
450 : reactor.
451 :
452 : Failures such as descriptor exhaustion are normal runtime
453 : conditions and are reported through the returned error code.
454 : Opening an already-open socket is a no-op that reports
455 : success.
456 :
457 : @param proto The protocol (IPv4 or IPv6). Defaults to
458 : `udp::v4()`.
459 :
460 : @return The error code, empty on success.
461 : */
462 : [[nodiscard]] std::error_code open(udp proto = udp::v4()) noexcept;
463 :
464 : /** Close the socket.
465 :
466 : Releases socket resources. Any pending operations complete
467 : with `errc::operation_canceled`.
468 : */
469 : void close() noexcept;
470 :
471 : /** Check if the socket is open.
472 :
473 : @return `true` if the socket is open and ready for operations.
474 : */
475 1712 : bool is_open() const noexcept
476 : {
477 : #if BOOST_COROSIO_HAS_IOCP && !defined(BOOST_COROSIO_MRDOCS)
478 : return h_ && get().native_handle() != ~native_handle_type(0);
479 : #else
480 1712 : return h_ && get().native_handle() >= 0;
481 : #endif
482 : }
483 :
484 : /** Bind the socket to a local endpoint.
485 :
486 : Associates the socket with a local address and port.
487 : Required before calling `recv_from`.
488 :
489 : @param ep The local endpoint to bind to.
490 :
491 : @return Error code on failure, empty on success.
492 :
493 : A closed socket reports `errc::bad_file_descriptor`.
494 : */
495 : [[nodiscard]] std::error_code bind(endpoint ep) noexcept;
496 :
497 : /** Disable sends or receives on the socket.
498 :
499 : Failures such as an unconnected socket are normal runtime
500 : conditions and are reported through the returned error
501 : code. A closed socket reports `errc::bad_file_descriptor`.
502 :
503 : @param what Determines what operations will no longer be
504 : allowed.
505 :
506 : @return The error code, empty on success.
507 : */
508 : [[nodiscard]] std::error_code shutdown(shutdown_type what) noexcept;
509 :
510 : /** Cancel any pending asynchronous operations.
511 :
512 : All outstanding operations complete with
513 : `errc::operation_canceled`. Check `ec == cond::canceled`
514 : for portable comparison.
515 : */
516 : void cancel() noexcept;
517 :
518 : /** Get the native socket handle.
519 :
520 : @return The native socket handle, or -1 if not open.
521 : */
522 : native_handle_type native_handle() const noexcept;
523 :
524 : /** Assign an existing native socket to this object.
525 :
526 : Adopts a UDP socket created outside the library — received
527 : from another process, inherited, or made natively — and
528 : registers it with the backend. The socket must be a datagram
529 : socket in the `AF_INET` or `AF_INET6` family. Adoption never
530 : alters the descriptor's flags or options: on POSIX the fd
531 : must already be non-blocking, and on Windows the socket must
532 : be overlapped-capable.
533 :
534 : If this object is already open, pending operations complete
535 : with `errc::operation_canceled` and the held socket is
536 : closed before the new one is adopted.
537 :
538 : @par Exception Safety
539 : Strong guarantee on validation failure: the object is
540 : unchanged. If backend registration fails, the object either
541 : retains its previous socket or is left closed, depending on
542 : the backend. In all failure cases the caller retains
543 : ownership of `fd`.
544 :
545 : @param fd The native socket to adopt. On success the object
546 : owns it and will close it.
547 :
548 : @return The error code, empty on success. Validation and
549 : registration failures are normal runtime conditions when
550 : adopting foreign descriptors.
551 : */
552 : [[nodiscard]] std::error_code assign(native_handle_type fd) noexcept;
553 :
554 : /** Release ownership of the native socket handle.
555 :
556 : Deregisters the socket from the backend and cancels pending
557 : operations without closing the descriptor. The caller takes
558 : ownership of the returned handle.
559 :
560 : @return The native handle.
561 :
562 : @throws std::system_error `errc::bad_file_descriptor` if the
563 : socket is not open.
564 :
565 : @post is_open() == false
566 : */
567 : native_handle_type release();
568 :
569 : /** Set a socket option.
570 :
571 : @param opt The option to set.
572 :
573 : @throws std::system_error `errc::bad_file_descriptor` if the
574 : socket is not open; otherwise thrown on failure.
575 : */
576 : template<class Option>
577 91 : void set_option(Option const& opt)
578 : {
579 91 : if (!is_open())
580 2 : detail::throw_system_error(
581 4 : make_error_code(std::errc::bad_file_descriptor),
582 : "udp_socket::set_option");
583 89 : std::error_code ec = get().set_option(
584 : Option::level(), Option::name(), opt.data(), opt.size());
585 89 : if (ec)
586 6 : detail::throw_system_error(ec, "udp_socket::set_option");
587 83 : }
588 :
589 : /** Get a socket option.
590 :
591 : @return The current option value.
592 :
593 : @throws std::system_error `errc::bad_file_descriptor` if the
594 : socket is not open; otherwise thrown on failure.
595 : */
596 : template<class Option>
597 57 : Option get_option() const
598 : {
599 57 : if (!is_open())
600 2 : detail::throw_system_error(
601 4 : make_error_code(std::errc::bad_file_descriptor),
602 : "udp_socket::get_option");
603 55 : Option opt{};
604 55 : std::size_t sz = opt.size();
605 : std::error_code ec =
606 55 : get().get_option(Option::level(), Option::name(), opt.data(), &sz);
607 55 : if (ec)
608 2 : detail::throw_system_error(ec, "udp_socket::get_option");
609 53 : opt.resize(sz);
610 53 : return opt;
611 : }
612 :
613 : /** Get the local endpoint of the socket.
614 :
615 : @return The local endpoint, or a default endpoint if not bound.
616 : */
617 : endpoint local_endpoint() const noexcept;
618 :
619 : /** Send a datagram to the specified destination.
620 :
621 : @param buf The buffer containing data to send.
622 : @param dest The destination endpoint.
623 : @param flags Message flags (e.g. message_flags::dont_route).
624 :
625 : @return An awaitable that completes with
626 : `io_result<std::size_t>`.
627 :
628 : A closed socket reports `errc::bad_file_descriptor`.
629 : */
630 : template<capy::ConstBufferSequence Buffers>
631 71 : [[nodiscard]] auto send_to(
632 : Buffers const& buf,
633 : endpoint dest,
634 : corosio::message_flags flags)
635 : {
636 71 : send_to_awaitable aw(*this, buf, dest, static_cast<int>(flags));
637 71 : if (!is_open())
638 2 : aw.ec_ = make_error_code(std::errc::bad_file_descriptor);
639 71 : return aw;
640 : }
641 :
642 : /// @overload
643 : template<capy::ConstBufferSequence Buffers>
644 71 : [[nodiscard]] auto send_to(Buffers const& buf, endpoint dest)
645 : {
646 71 : return send_to(buf, dest, corosio::message_flags::none);
647 : }
648 :
649 : /** Receive a datagram and capture the sender's endpoint.
650 :
651 : @param buf The buffer to receive data into.
652 : @param source Reference to an endpoint that will be set to
653 : the sender's address on successful completion.
654 : @param flags Message flags (e.g. message_flags::peek).
655 :
656 : @return An awaitable that completes with
657 : `io_result<std::size_t>`.
658 :
659 : A closed socket reports `errc::bad_file_descriptor`.
660 : */
661 : template<capy::MutableBufferSequence Buffers>
662 91 : [[nodiscard]] auto recv_from(
663 : Buffers const& buf,
664 : endpoint& source,
665 : corosio::message_flags flags)
666 : {
667 91 : recv_from_awaitable aw(*this, buf, source, static_cast<int>(flags));
668 91 : if (!is_open())
669 2 : aw.ec_ = make_error_code(std::errc::bad_file_descriptor);
670 91 : return aw;
671 : }
672 :
673 : /// @overload
674 : template<capy::MutableBufferSequence Buffers>
675 90 : [[nodiscard]] auto recv_from(Buffers const& buf, endpoint& source)
676 : {
677 90 : return recv_from(buf, source, corosio::message_flags::none);
678 : }
679 :
680 : /** Initiate an asynchronous connect to set the default peer.
681 :
682 : If the socket is not already open, it is opened automatically
683 : using the address family of @p ep.
684 :
685 : @param ep The remote endpoint to connect to.
686 :
687 : @return An awaitable that completes with `io_result<>`.
688 :
689 : If the socket needs to be opened and the open fails, the
690 : awaitable completes immediately with that error.
691 : */
692 40 : [[nodiscard]] auto connect(endpoint ep)
693 : {
694 40 : connect_awaitable aw(*this, ep);
695 40 : if (!is_open())
696 8 : aw.ec_ = open(ep.is_v6() ? udp::v6() : udp::v4());
697 40 : return aw;
698 : }
699 :
700 : /** Wait for the socket to become ready in a given direction.
701 :
702 : Suspends until the socket is ready for the requested
703 : direction, or an error condition is reported. No bytes
704 : are transferred.
705 :
706 : The operation supports cancellation via `std::stop_token`.
707 :
708 : @param w The wait direction (read, write, or error).
709 :
710 : @return An awaitable that completes with `io_result<>`.
711 :
712 : A closed socket completes with `errc::bad_file_descriptor`.
713 :
714 : @par Preconditions
715 : This socket must outlive the returned awaitable.
716 : */
717 30 : [[nodiscard]] auto wait(wait_type w)
718 : {
719 30 : return wait_awaitable(*this, w);
720 : }
721 :
722 : /** Send a datagram to the connected peer.
723 :
724 : @param buf The buffer containing data to send.
725 : @param flags Message flags.
726 :
727 : @return An awaitable that completes with
728 : `io_result<std::size_t>`.
729 :
730 : A closed socket reports `errc::bad_file_descriptor`.
731 : */
732 : template<capy::ConstBufferSequence Buffers>
733 26 : [[nodiscard]] auto send(Buffers const& buf, corosio::message_flags flags)
734 : {
735 26 : send_awaitable aw(*this, buf, static_cast<int>(flags));
736 26 : if (!is_open())
737 2 : aw.ec_ = make_error_code(std::errc::bad_file_descriptor);
738 26 : return aw;
739 : }
740 :
741 : /// @overload
742 : template<capy::ConstBufferSequence Buffers>
743 26 : [[nodiscard]] auto send(Buffers const& buf)
744 : {
745 26 : return send(buf, corosio::message_flags::none);
746 : }
747 :
748 : /** Receive a datagram from the connected peer.
749 :
750 : @param buf The buffer to receive data into.
751 : @param flags Message flags (e.g. message_flags::peek).
752 :
753 : @return An awaitable that completes with
754 : `io_result<std::size_t>`.
755 :
756 : A closed socket reports `errc::bad_file_descriptor`.
757 : */
758 : template<capy::MutableBufferSequence Buffers>
759 61 : [[nodiscard]] auto recv(Buffers const& buf, corosio::message_flags flags)
760 : {
761 61 : recv_awaitable aw(*this, buf, static_cast<int>(flags));
762 61 : if (!is_open())
763 2 : aw.ec_ = make_error_code(std::errc::bad_file_descriptor);
764 61 : return aw;
765 : }
766 :
767 : /// @overload
768 : template<capy::MutableBufferSequence Buffers>
769 61 : [[nodiscard]] auto recv(Buffers const& buf)
770 : {
771 61 : return recv(buf, corosio::message_flags::none);
772 : }
773 :
774 : /** Get the remote endpoint of the socket.
775 :
776 : Returns the address and port of the connected peer.
777 :
778 : @return The remote endpoint, or a default endpoint if
779 : not connected.
780 : */
781 : endpoint remote_endpoint() const noexcept;
782 :
783 : protected:
784 : /// Construct from a pre-built handle (for native_udp_socket).
785 42 : explicit udp_socket(io_object::handle h) noexcept : io_object(std::move(h))
786 : {
787 42 : }
788 :
789 : private:
790 : /// Open the socket for the given protocol triple.
791 : [[nodiscard]] std::error_code
792 : open_for_family(int family, int type, int protocol) noexcept;
793 :
794 2365 : inline implementation& get() const noexcept
795 : {
796 2365 : return *static_cast<implementation*>(h_.get());
797 : }
798 : };
799 :
800 : } // namespace boost::corosio
801 :
802 : #endif // BOOST_COROSIO_UDP_SOCKET_HPP
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