TLA Line data Source code
1 : //
2 : // Copyright (c) 2026 Michael Vandeberg
3 : //
4 : // Distributed under the Boost Software License, Version 1.0. (See accompanying
5 : // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
6 : //
7 : // Official repository: https://github.com/cppalliance/corosio
8 : //
9 :
10 : #ifndef BOOST_COROSIO_LOCAL_DATAGRAM_SOCKET_HPP
11 : #define BOOST_COROSIO_LOCAL_DATAGRAM_SOCKET_HPP
12 :
13 : #include <boost/corosio/family.hpp>
14 : #include <boost/corosio/detail/config.hpp>
15 : #include <boost/corosio/detail/platform.hpp>
16 :
17 : #if BOOST_COROSIO_POSIX
18 :
19 : #include <boost/corosio/detail/except.hpp>
20 : #include <boost/corosio/detail/native_handle.hpp>
21 : #include <boost/corosio/detail/op_base.hpp>
22 : #include <boost/corosio/io/io_object.hpp>
23 : #include <boost/capy/results.hpp>
24 : #include <boost/corosio/detail/buffer_param.hpp>
25 : #include <boost/corosio/error.hpp>
26 : #include <boost/corosio/local_endpoint.hpp>
27 : #include <boost/corosio/message_flags.hpp>
28 : #include <boost/corosio/shutdown_type.hpp>
29 : #include <boost/corosio/wait_type.hpp>
30 : #include <boost/capy/ex/executor_ref.hpp>
31 : #include <boost/capy/ex/execution_context.hpp>
32 : #include <boost/capy/ex/await_context.hpp>
33 : #include <boost/capy/concept/executor.hpp>
34 :
35 : #include <system_error>
36 :
37 : #include <concepts>
38 : #include <boost/capy/continuation.hpp>
39 :
40 : #include <coroutine>
41 : #include <cstddef>
42 : #include <stop_token>
43 : #include <type_traits>
44 :
45 : namespace boost::corosio {
46 :
47 : /** Sends and receives datagrams over a Unix domain socket, from a coroutine.
48 :
49 : This class provides asynchronous Unix domain datagram socket
50 : operations that return awaitable types. Each operation
51 : participates in the affine awaitable protocol, ensuring
52 : coroutines resume on the correct executor.
53 :
54 : Supports two modes of operation:
55 :
56 : @li **Connectionless:** each send_to() specifies a destination
57 : endpoint, and each recv_from() captures the source. The
58 : socket must be opened (and optionally bound) before I/O.
59 :
60 : @li **Connected:** call connect() to set a default peer,
61 : then use send()/recv() without endpoint arguments. The
62 : kernel filters incoming datagrams to those from the
63 : connected peer.
64 :
65 : @note Not available on Windows. Windows does not support
66 : AF_UNIX datagram sockets (SOCK_DGRAM). Attempting to
67 : open this socket on Windows fails.
68 :
69 : @par Cancellation
70 : All asynchronous operations support cancellation through
71 : `std::stop_token` via the affine protocol, or explicitly
72 : through cancel(). Cancelled operations complete with
73 : `capy::cond::canceled`. Datagram sends and receives are
74 : atomic — there is no partial progress on cancellation.
75 :
76 : @par Thread Safety
77 : Distinct objects: Safe.@n
78 : Shared objects: Unsafe. A socket must not have concurrent
79 : operations of the same type (e.g., two simultaneous
80 : `recv_from`). One send and one `recv` may be in flight
81 : simultaneously. Both `recv` and `recv_from` share the
82 : same internal read slot, so they must not overlap. Likewise,
83 : send and `send_to` share the write slot.
84 :
85 : @par Example
86 : @par !example connectionless_and_connected
87 : */
88 : class BOOST_COROSIO_DECL local_datagram_socket : public io_object
89 : {
90 : public:
91 : /// The shutdown direction type used by shutdown().
92 : using shutdown_type = corosio::shutdown_type;
93 : using enum corosio::shutdown_type;
94 :
95 : /** Define backend hooks for local datagram socket operations.
96 :
97 : Platform backends (epoll, kqueue, select) derive from this
98 : to implement datagram I/O, connection, and option management.
99 : */
100 : struct implementation : io_object::implementation
101 : {
102 : /** Initiate an asynchronous `send_to` operation.
103 :
104 : @param cont Continuation to resume on completion; it lives in
105 : the awaiting frame until then.
106 : @param ex Executor for dispatching the completion.
107 : @param buf The buffer data to send.
108 : @param dest The destination endpoint.
109 : @param flags Message flags (e.g. `message_flags::do_not_route`).
110 : @param token Stop token for cancellation.
111 : @param ec Output error code.
112 : @param bytes_out Output bytes transferred.
113 :
114 : @return Coroutine handle to resume immediately.
115 : */
116 : virtual std::coroutine_handle<> send_to(
117 : capy::continuation& cont,
118 : capy::executor_ref ex,
119 : buffer_param buf,
120 : corosio::local_endpoint dest,
121 : int flags,
122 : std::stop_token token,
123 : std::error_code* ec,
124 : std::size_t* bytes_out) = 0;
125 :
126 : /** Initiate an asynchronous `recv_from` operation.
127 :
128 : @param cont Continuation to resume on completion; it lives in
129 : the awaiting frame until then.
130 : @param ex Executor for dispatching the completion.
131 : @param buf The buffer to receive into.
132 : @param source Output endpoint for the sender's address.
133 : @param flags Message flags (e.g. `message_flags::peek`).
134 : @param token Stop token for cancellation.
135 : @param ec Output error code.
136 : @param bytes_out Output bytes transferred.
137 :
138 : @return Coroutine handle to resume immediately.
139 : */
140 : virtual std::coroutine_handle<> recv_from(
141 : capy::continuation& cont,
142 : capy::executor_ref ex,
143 : buffer_param buf,
144 : corosio::local_endpoint* source,
145 : int flags,
146 : std::stop_token token,
147 : std::error_code* ec,
148 : std::size_t* bytes_out) = 0;
149 :
150 : /** Initiate an asynchronous connect to set the default peer.
151 :
152 : @param cont Continuation to resume on completion; it lives in
153 : the awaiting frame until then.
154 : @param ex Executor for dispatching the completion.
155 : @param ep The remote endpoint to connect to.
156 : @param token Stop token for cancellation.
157 : @param ec Output error code.
158 :
159 : @return Coroutine handle to resume immediately.
160 : */
161 : virtual std::coroutine_handle<> connect(
162 : capy::continuation& cont,
163 : capy::executor_ref ex,
164 : corosio::local_endpoint ep,
165 : std::stop_token token,
166 : std::error_code* ec) = 0;
167 :
168 : /** Initiate an asynchronous connected send operation.
169 :
170 : @param cont Continuation to resume on completion; it lives in
171 : the awaiting frame until then.
172 : @param ex Executor for dispatching the completion.
173 : @param buf The buffer data to send.
174 : @param flags Message flags (e.g. `message_flags::do_not_route`).
175 : @param token Stop token for cancellation.
176 : @param ec Output error code.
177 : @param bytes_out Output bytes transferred.
178 :
179 : @return Coroutine handle to resume immediately.
180 : */
181 : virtual std::coroutine_handle<> send(
182 : capy::continuation& cont,
183 : capy::executor_ref ex,
184 : buffer_param buf,
185 : int flags,
186 : std::stop_token token,
187 : std::error_code* ec,
188 : std::size_t* bytes_out) = 0;
189 :
190 : /** Initiate an asynchronous connected `recv` operation.
191 :
192 : @param cont Continuation to resume on completion; it lives in
193 : the awaiting frame until then.
194 : @param ex Executor for dispatching the completion.
195 : @param buf The buffer to receive into.
196 : @param flags Message flags (e.g. `message_flags::peek`).
197 : @param token Stop token for cancellation.
198 : @param ec Output error code.
199 : @param bytes_out Output bytes transferred.
200 :
201 : @return Coroutine handle to resume immediately.
202 : */
203 : virtual std::coroutine_handle<> recv(
204 : capy::continuation& cont,
205 : capy::executor_ref ex,
206 : buffer_param buf,
207 : int flags,
208 : std::stop_token token,
209 : std::error_code* ec,
210 : std::size_t* bytes_out) = 0;
211 :
212 : /** Initiate an asynchronous wait for socket readiness.
213 :
214 : Completes when the socket becomes ready for the
215 : specified direction, or an error condition is
216 : reported. No bytes are transferred.
217 :
218 : @param cont Continuation to resume on completion; it lives in
219 : the awaiting frame until then.
220 : @param ex Executor for dispatching the completion.
221 : @param w The direction to wait on.
222 : @param token Stop token for cancellation.
223 : @param ec Output error code.
224 :
225 : @return Coroutine handle to resume immediately.
226 : */
227 : virtual std::coroutine_handle<> wait(
228 : capy::continuation& cont,
229 : capy::executor_ref ex,
230 : wait_type w,
231 : std::stop_token token,
232 : std::error_code* ec) = 0;
233 :
234 : /** Shut down part or all of the socket.
235 :
236 : @param what Which directions to disable.
237 :
238 : @return The error code, empty on success.
239 : */
240 : virtual std::error_code shutdown(shutdown_type what) noexcept = 0;
241 :
242 : /// Return the platform socket descriptor.
243 : virtual native_handle_type native_handle() const noexcept = 0;
244 :
245 : /** Return the socket's address family.
246 :
247 : Local sockets have no IP family; implementations return
248 : `v4`, which the family-neutral options applicable to them
249 : ignore.
250 :
251 : @return The address family for option rendering.
252 : */
253 : virtual corosio::family family() const noexcept = 0;
254 :
255 : /** Release ownership of the socket descriptor.
256 :
257 : The implementation deregisters from the reactor and cancels
258 : pending operations. The caller takes ownership of the
259 : returned descriptor.
260 :
261 : @return The native handle, or an invalid sentinel if
262 : not open.
263 : */
264 : virtual native_handle_type release_socket() noexcept = 0;
265 :
266 : /** Request cancellation of pending asynchronous operations.
267 :
268 : Operations still in flight complete with `operation_canceled`;
269 : an operation whose result is already decided reports that
270 : result. Check `ec == cond::canceled` for portable comparison.
271 : */
272 : virtual void cancel() noexcept = 0;
273 :
274 : /** Set a socket option.
275 :
276 : @param level The protocol level (e.g. SOL_SOCKET).
277 : @param optname The option name.
278 : @param data Pointer to the option value.
279 : @param size Size of the option value in bytes.
280 : @return Error code on failure, empty on success.
281 : */
282 : virtual std::error_code set_option(
283 : int level,
284 : int optname,
285 : void const* data,
286 : std::size_t size) noexcept = 0;
287 :
288 : /** Get a socket option.
289 :
290 : @param level The protocol level (e.g. SOL_SOCKET).
291 : @param optname The option name.
292 : @param data Pointer to receive the option value.
293 : @param size On entry, the size of the buffer. On exit,
294 : the size of the option value.
295 : @return Error code on failure, empty on success.
296 : */
297 : virtual std::error_code
298 : get_option(int level, int optname, void* data, std::size_t* size)
299 : const noexcept = 0;
300 :
301 : /// Return the cached local endpoint.
302 : virtual corosio::local_endpoint local_endpoint() const noexcept = 0;
303 :
304 : /// Return the cached remote endpoint (connected mode).
305 : virtual corosio::local_endpoint remote_endpoint() const noexcept = 0;
306 :
307 : /** Bind the socket to a local endpoint.
308 :
309 : @param ep The local endpoint to bind to.
310 : @return Error code on failure, empty on success.
311 : */
312 : virtual std::error_code bind(corosio::local_endpoint ep) noexcept = 0;
313 : };
314 :
315 : /** Represent the awaitable returned by @ref send_to.
316 :
317 : Captures the destination endpoint and buffer, then dispatches
318 : to the backend implementation on suspension.
319 : */
320 : struct send_to_awaitable : detail::bytes_op_base<send_to_awaitable>
321 : {
322 : private:
323 : friend local_datagram_socket;
324 :
325 HIT 88 : send_to_awaitable(
326 : local_datagram_socket& s,
327 : buffer_param buf,
328 : corosio::local_endpoint dest,
329 : int flags = 0) noexcept
330 176 : : s_(s)
331 88 : , buf_(buf)
332 88 : , dest_(dest)
333 88 : , flags_(flags)
334 : {
335 88 : }
336 :
337 : friend detail::bytes_op_base<send_to_awaitable>;
338 :
339 : local_datagram_socket& s_;
340 : buffer_param buf_;
341 : corosio::local_endpoint dest_;
342 : int flags_;
343 :
344 : std::coroutine_handle<>
345 84 : dispatch(capy::continuation& cont, capy::executor_ref ex) const
346 : {
347 168 : return s_.get().send_to(
348 168 : cont, ex, buf_, dest_, flags_, token_, &ec_, &bytes_);
349 : }
350 : };
351 :
352 : /** Represent the awaitable returned by @ref recv_from.
353 :
354 : Captures the source endpoint reference and buffer, then
355 : dispatches to the backend implementation on suspension.
356 : */
357 : struct recv_from_awaitable : detail::bytes_op_base<recv_from_awaitable>
358 : {
359 : private:
360 : friend local_datagram_socket;
361 :
362 88 : recv_from_awaitable(
363 : local_datagram_socket& s,
364 : buffer_param buf,
365 : corosio::local_endpoint& source,
366 : int flags = 0) noexcept
367 176 : : s_(s)
368 88 : , buf_(buf)
369 88 : , source_(source)
370 88 : , flags_(flags)
371 : {
372 88 : }
373 :
374 : friend detail::bytes_op_base<recv_from_awaitable>;
375 :
376 : local_datagram_socket& s_;
377 : buffer_param buf_;
378 : corosio::local_endpoint& source_;
379 : int flags_;
380 :
381 : std::coroutine_handle<>
382 84 : dispatch(capy::continuation& cont, capy::executor_ref ex) const
383 : {
384 168 : return s_.get().recv_from(
385 168 : cont, ex, buf_, &source_, flags_, token_, &ec_, &bytes_);
386 : }
387 : };
388 :
389 : /** Represent the awaitable returned by @ref connect.
390 :
391 : Captures the target endpoint, then dispatches to the
392 : backend implementation on suspension.
393 : */
394 : struct connect_awaitable : detail::void_op_base<connect_awaitable>
395 : {
396 : private:
397 : friend local_datagram_socket;
398 :
399 2 : connect_awaitable(
400 : local_datagram_socket& s, corosio::local_endpoint ep) noexcept
401 4 : : s_(s)
402 2 : , endpoint_(ep)
403 : {
404 2 : }
405 :
406 : friend detail::void_op_base<connect_awaitable>;
407 :
408 : local_datagram_socket& s_;
409 : corosio::local_endpoint endpoint_;
410 :
411 : std::coroutine_handle<>
412 2 : dispatch(capy::continuation& cont, capy::executor_ref ex) const
413 : {
414 2 : return s_.get().connect(cont, ex, endpoint_, token_, &ec_);
415 : }
416 : };
417 :
418 : /// Represent the awaitable returned by @ref wait.
419 : struct wait_awaitable : detail::void_op_base<wait_awaitable>
420 : {
421 : private:
422 : friend local_datagram_socket;
423 :
424 14 : wait_awaitable(local_datagram_socket& s, wait_type w) noexcept
425 28 : : s_(s)
426 14 : , w_(w)
427 : {
428 14 : }
429 :
430 : friend detail::void_op_base<wait_awaitable>;
431 :
432 : local_datagram_socket& s_;
433 : wait_type w_;
434 :
435 : std::coroutine_handle<>
436 12 : dispatch(capy::continuation& cont, capy::executor_ref ex) const
437 : {
438 12 : return s_.get().wait(cont, ex, w_, token_, &ec_);
439 : }
440 : };
441 :
442 : /** Represent the awaitable returned by @ref send.
443 :
444 : Captures the buffer, then dispatches to the backend
445 : implementation on suspension. Requires a prior connect().
446 : */
447 : struct send_awaitable : detail::bytes_op_base<send_awaitable>
448 : {
449 : private:
450 : friend local_datagram_socket;
451 :
452 97 : send_awaitable(
453 : local_datagram_socket& s, buffer_param buf, int flags = 0) noexcept
454 194 : : s_(s)
455 97 : , buf_(buf)
456 97 : , flags_(flags)
457 : {
458 97 : }
459 :
460 : friend detail::bytes_op_base<send_awaitable>;
461 :
462 : local_datagram_socket& s_;
463 : buffer_param buf_;
464 : int flags_;
465 :
466 : std::coroutine_handle<>
467 93 : dispatch(capy::continuation& cont, capy::executor_ref ex) const
468 : {
469 93 : return s_.get().send(cont, ex, buf_, flags_, token_, &ec_, &bytes_);
470 : }
471 : };
472 :
473 : /** Represent the awaitable returned by @ref recv.
474 :
475 : Captures the buffer, then dispatches to the backend
476 : implementation on suspension. Requires a prior connect().
477 : */
478 : struct recv_awaitable : detail::bytes_op_base<recv_awaitable>
479 : {
480 : private:
481 : friend local_datagram_socket;
482 :
483 97 : recv_awaitable(
484 : local_datagram_socket& s, buffer_param buf, int flags = 0) noexcept
485 194 : : s_(s)
486 97 : , buf_(buf)
487 97 : , flags_(flags)
488 : {
489 97 : }
490 :
491 : friend detail::bytes_op_base<recv_awaitable>;
492 :
493 : local_datagram_socket& s_;
494 : buffer_param buf_;
495 : int flags_;
496 :
497 : std::coroutine_handle<>
498 93 : dispatch(capy::continuation& cont, capy::executor_ref ex) const
499 : {
500 93 : return s_.get().recv(cont, ex, buf_, flags_, token_, &ec_, &bytes_);
501 : }
502 : };
503 :
504 : public:
505 : /** Destructor.
506 :
507 : Closes the socket if open, cancelling any pending operations.
508 : */
509 : ~local_datagram_socket() override;
510 :
511 : /** Construct a socket from an execution context.
512 :
513 : @param ctx The execution context that owns this socket.
514 : */
515 : explicit local_datagram_socket(capy::execution_context& ctx);
516 :
517 : /** Construct a socket from an executor.
518 :
519 : The socket is associated with the executor's context.
520 :
521 : @tparam Ex A type satisfying capy::Executor.
522 :
523 : @param ex The executor whose context owns the socket.
524 : */
525 : template<class Ex>
526 : requires(!std::
527 : same_as<std::remove_cvref_t<Ex>, local_datagram_socket>) &&
528 : capy::Executor<Ex>
529 : explicit local_datagram_socket(Ex const& ex)
530 : : local_datagram_socket(ex.context())
531 : {
532 : }
533 :
534 : /** Move constructor.
535 :
536 : Transfers ownership of the socket resources.
537 :
538 : @param other The socket to move from.
539 : */
540 2 : local_datagram_socket(local_datagram_socket&& other) noexcept
541 2 : : io_object(std::move(other))
542 : {
543 2 : }
544 :
545 : /** Move assignment operator.
546 :
547 : Closes any existing socket and transfers ownership.
548 :
549 : @param other The socket to move from.
550 : @return Reference to this socket.
551 : */
552 2 : local_datagram_socket& operator=(local_datagram_socket&& other) noexcept
553 : {
554 2 : if (this != &other)
555 : {
556 2 : close();
557 2 : io_object::operator=(std::move(other));
558 : }
559 2 : return *this;
560 : }
561 :
562 : /// Copy construction is disabled; the handle is uniquely owned.
563 : local_datagram_socket(local_datagram_socket const&) = delete;
564 : /// Copy assignment is disabled; the handle is uniquely owned.
565 : local_datagram_socket& operator=(local_datagram_socket const&) = delete;
566 :
567 : /** Open the socket.
568 :
569 : Creates a Unix datagram socket and associates it with
570 : the platform reactor.
571 :
572 : Failures such as descriptor exhaustion are normal runtime
573 : conditions and are reported through the returned error code.
574 : Opening an already-open socket is a no-op that reports
575 : success.
576 :
577 :
578 : @return The error code, empty on success.
579 : */
580 : [[nodiscard]] std::error_code open() noexcept;
581 :
582 : /** Close the socket.
583 :
584 : Cancels any pending asynchronous operations and releases
585 : the underlying file descriptor. Has no effect if the
586 : socket is not open.
587 :
588 : @post is_open() == false
589 : */
590 : void close() noexcept;
591 :
592 : /** Check if the socket is open.
593 :
594 : @return `true` if the socket holds a valid file descriptor,
595 : `false` otherwise.
596 : */
597 1401 : bool is_open() const noexcept
598 : {
599 : #if BOOST_COROSIO_HAS_IOCP && !defined(BOOST_COROSIO_MRDOCS)
600 : return h_ && get().native_handle() != ~native_handle_type(0);
601 : #else
602 1401 : return h_ && get().native_handle() >= 0;
603 : #endif
604 : }
605 :
606 : /** Bind the socket to a local endpoint.
607 :
608 : Associates the socket with a local address (filesystem path).
609 : Required before calling `recv_from` in connectionless mode.
610 :
611 : @param ep The local endpoint to bind to.
612 :
613 : @return Error code on failure, empty on success.
614 :
615 : A closed socket reports `errc::bad_file_descriptor`.
616 : */
617 : [[nodiscard]] std::error_code bind(corosio::local_endpoint ep) noexcept;
618 :
619 : /** Initiate an asynchronous connect to set the default peer.
620 :
621 : If the socket is not already open, it is opened automatically.
622 : After successful completion, send()/recv() may be used
623 : without specifying an endpoint.
624 :
625 : @param ep The remote endpoint to connect to.
626 :
627 : @par Cancellation
628 : Supports cancellation via the awaitable's stop_token or by
629 : calling cancel(). On cancellation, yields
630 : `capy::cond::canceled`.
631 :
632 : @return An awaitable that completes with `results<>`.
633 :
634 : If the socket needs to be opened and the open fails, the
635 : awaitable completes immediately with that error.
636 : */
637 2 : [[nodiscard]] auto connect(corosio::local_endpoint ep)
638 : {
639 2 : connect_awaitable aw(*this, ep);
640 2 : if (!is_open())
641 2 : aw.ec_ = open();
642 2 : return aw;
643 : }
644 :
645 : /** Wait for the socket to become ready in a given direction.
646 :
647 : Suspends until the socket is ready for the requested
648 : direction, or an error condition is reported. No bytes
649 : are transferred.
650 :
651 : @param w The wait direction (read, write, or error).
652 :
653 : @return An awaitable that completes with `results<>`.
654 :
655 : A closed socket completes with `errc::bad_file_descriptor`.
656 :
657 : @pre This socket must outlive the returned awaitable.
658 : */
659 14 : [[nodiscard]] auto wait(wait_type w)
660 : {
661 14 : return wait_awaitable(*this, w);
662 : }
663 :
664 : /** Send a datagram to the specified destination.
665 :
666 : Completes when the transport accepts the entire datagram
667 : by the kernel. The `bytes_transferred` value equals the
668 : datagram size on success.
669 :
670 : @param buf The buffer containing data to send.
671 : @param dest The destination endpoint.
672 : @param flags Message flags (e.g. message_flags::do_not_route).
673 :
674 : @par Cancellation
675 : Supports cancellation via stop_token or cancel().
676 :
677 : @return An awaitable that completes with
678 : results<std::size_t>.
679 :
680 : A closed socket reports `errc::bad_file_descriptor`.
681 : */
682 : template<capy::ConstBufferSequence Buffers>
683 88 : [[nodiscard]] auto send_to(
684 : Buffers const& buf,
685 : corosio::local_endpoint dest,
686 : corosio::message_flags flags)
687 : {
688 88 : send_to_awaitable aw(*this, buf, dest, static_cast<int>(flags));
689 88 : if (!is_open())
690 2 : aw.ec_ = make_error_code(std::errc::bad_file_descriptor);
691 88 : return aw;
692 : }
693 :
694 : /// @overload
695 : template<capy::ConstBufferSequence Buffers>
696 88 : [[nodiscard]] auto send_to(Buffers const& buf, corosio::local_endpoint dest)
697 : {
698 88 : return send_to(buf, dest, corosio::message_flags::none);
699 : }
700 :
701 : /** Receive a datagram and capture the sender's endpoint.
702 :
703 : Completes when one datagram arrives. The
704 : `bytes_transferred` value is the number of bytes copied
705 : into the buffer. If the buffer is smaller than the
706 : datagram, excess bytes are discarded (datagram
707 : semantics).
708 :
709 : @param buf The buffer to receive data into.
710 : @param source Reference to an endpoint that receives
711 : the sender's address on successful completion.
712 : @param flags Message flags (e.g. message_flags::peek).
713 :
714 : @par Cancellation
715 : Supports cancellation via stop_token or cancel().
716 :
717 : @return An awaitable that completes with
718 : results<std::size_t>.
719 :
720 : A closed socket reports `errc::bad_file_descriptor`.
721 : */
722 : template<capy::MutableBufferSequence Buffers>
723 88 : [[nodiscard]] auto recv_from(
724 : Buffers const& buf,
725 : corosio::local_endpoint& source,
726 : corosio::message_flags flags)
727 : {
728 88 : recv_from_awaitable aw(*this, buf, source, static_cast<int>(flags));
729 88 : if (!is_open())
730 2 : aw.ec_ = make_error_code(std::errc::bad_file_descriptor);
731 88 : return aw;
732 : }
733 :
734 : /// @overload
735 : template<capy::MutableBufferSequence Buffers>
736 : [[nodiscard]] auto
737 86 : recv_from(Buffers const& buf, corosio::local_endpoint& source)
738 : {
739 86 : return recv_from(buf, source, corosio::message_flags::none);
740 : }
741 :
742 : /** Send a datagram to the connected peer.
743 :
744 : @pre connect() succeeded.
745 :
746 : @param buf The buffer containing data to send.
747 : @param flags Message flags.
748 :
749 : @par Cancellation
750 : Supports cancellation via stop_token or cancel().
751 :
752 : @return An awaitable that completes with
753 : results<std::size_t>.
754 :
755 : A closed socket reports `errc::bad_file_descriptor`.
756 : */
757 : template<capy::ConstBufferSequence Buffers>
758 97 : [[nodiscard]] auto send(Buffers const& buf, corosio::message_flags flags)
759 : {
760 97 : send_awaitable aw(*this, buf, static_cast<int>(flags));
761 97 : if (!is_open())
762 2 : aw.ec_ = make_error_code(std::errc::bad_file_descriptor);
763 97 : return aw;
764 : }
765 :
766 : /// @overload
767 : template<capy::ConstBufferSequence Buffers>
768 97 : [[nodiscard]] auto send(Buffers const& buf)
769 : {
770 97 : return send(buf, corosio::message_flags::none);
771 : }
772 :
773 : /** Receive a datagram from the connected peer.
774 :
775 : @pre connect() succeeded.
776 :
777 : @param buf The buffer to receive data into.
778 : @param flags Message flags (e.g. message_flags::peek).
779 :
780 : @par Cancellation
781 : Supports cancellation via stop_token or cancel().
782 :
783 : @return An awaitable that completes with
784 : results<std::size_t>.
785 :
786 : A closed socket reports `errc::bad_file_descriptor`.
787 : */
788 : template<capy::MutableBufferSequence Buffers>
789 97 : [[nodiscard]] auto recv(Buffers const& buf, corosio::message_flags flags)
790 : {
791 97 : recv_awaitable aw(*this, buf, static_cast<int>(flags));
792 97 : if (!is_open())
793 2 : aw.ec_ = make_error_code(std::errc::bad_file_descriptor);
794 97 : return aw;
795 : }
796 :
797 : /// @overload
798 : template<capy::MutableBufferSequence Buffers>
799 95 : [[nodiscard]] auto recv(Buffers const& buf)
800 : {
801 95 : return recv(buf, corosio::message_flags::none);
802 : }
803 :
804 : /** Cancel any pending asynchronous operations.
805 :
806 : Operations still in flight complete with
807 : `errc::operation_canceled`; an operation whose result is
808 : already decided reports that result. Check
809 : `ec == cond::canceled` for portable comparison.
810 : */
811 : void cancel() noexcept;
812 :
813 : /** Get the native socket handle.
814 :
815 : @return The native socket handle, or -1 if not open.
816 : */
817 : native_handle_type native_handle() const noexcept;
818 :
819 : /** Release ownership of the native socket handle.
820 :
821 : Deregisters the socket from the reactor and cancels pending
822 : operations without closing the fd. The caller takes ownership
823 : of the returned descriptor.
824 :
825 : @return The native handle.
826 :
827 : @throws std::system_error `errc::bad_file_descriptor` if the
828 : socket is not open.
829 : */
830 : native_handle_type release();
831 :
832 : /** Query the number of bytes available for reading.
833 :
834 : @return The number of bytes that can be read without blocking.
835 :
836 : @throws std::system_error `errc::bad_file_descriptor` if the
837 : socket is not open; otherwise thrown on ioctl failure.
838 : */
839 : std::size_t available() const;
840 :
841 : /** Shut down part or all of the socket.
842 :
843 : Failures such as an unconnected socket are normal runtime
844 : conditions and are reported through the returned error
845 : code. A closed socket reports `errc::bad_file_descriptor`.
846 :
847 : @param what Which direction to shut down.
848 :
849 : @return The error code, empty on success.
850 : */
851 : [[nodiscard]] std::error_code shutdown(shutdown_type what) noexcept;
852 :
853 : /** Set a socket option.
854 :
855 : @tparam Option A socket option type that provides static
856 : `level()` and `name()` members, and `data()` / `size()`
857 : accessors for the option value.
858 :
859 : @param opt The option to set.
860 :
861 : @throws std::system_error `errc::bad_file_descriptor` if the
862 : socket is not open; otherwise thrown on failure.
863 : */
864 : template<class Option>
865 24 : void set_option(Option const& opt)
866 : {
867 24 : if (!is_open())
868 2 : detail::throw_system_error(
869 4 : make_error_code(std::errc::bad_file_descriptor),
870 : "local_datagram_socket::set_option");
871 22 : auto const fam = get().family();
872 22 : std::error_code ec = get().set_option(
873 : opt.level(fam), opt.name(fam), opt.data(fam), opt.size(fam));
874 22 : if (ec)
875 2 : detail::throw_system_error(ec, "local_datagram_socket::set_option");
876 20 : }
877 :
878 : /** Get a socket option.
879 :
880 : @tparam Option A socket option type that provides static
881 : `level()` and `name()` members, `data()` / `size()`
882 : accessors, and a `resize()` member.
883 :
884 : @return The current option value.
885 :
886 : @throws std::system_error `errc::bad_file_descriptor` if the
887 : socket is not open; otherwise thrown on failure.
888 : */
889 : template<class Option>
890 8 : Option get_option() const
891 : {
892 8 : if (!is_open())
893 2 : detail::throw_system_error(
894 4 : make_error_code(std::errc::bad_file_descriptor),
895 : "local_datagram_socket::get_option");
896 6 : Option opt{};
897 6 : auto const fam = get().family();
898 6 : std::size_t sz = opt.size(fam);
899 : std::error_code ec =
900 6 : get().get_option(opt.level(fam), opt.name(fam), opt.data(fam), &sz);
901 6 : if (ec)
902 2 : detail::throw_system_error(ec, "local_datagram_socket::get_option");
903 4 : opt.resize(fam, sz);
904 4 : return opt;
905 : }
906 :
907 : /** Assign an existing native socket to this object.
908 :
909 : Adopts a Unix domain datagram socket created outside the
910 : library — from `socketpair()`, received over `SCM_RIGHTS`,
911 : or made natively — and registers it with the backend. The
912 : socket must be a datagram socket in the `AF_UNIX` family.
913 : Adoption never alters the descriptor's flags or options.
914 : The fd must already be non-blocking.
915 :
916 : The object must be closed. To replace a held socket, `close()`
917 : or `release()` it first.
918 :
919 : @par Exception Safety
920 : Throws nothing. On failure the object is unchanged and the
921 : caller retains ownership of `fd`.
922 :
923 : @param fd The native socket to adopt. On success the object
924 : owns it and closes it.
925 :
926 : @return `error::already_open` if this object is open.
927 : Otherwise the error code, empty on success. Validation and
928 : registration failures are normal runtime conditions when
929 : adopting foreign descriptors.
930 : */
931 : [[nodiscard]] std::error_code assign(native_handle_type fd) noexcept;
932 :
933 : /** Get the local endpoint of the socket.
934 :
935 : @return The local endpoint, or a default endpoint if not bound.
936 : */
937 : corosio::local_endpoint local_endpoint() const noexcept;
938 :
939 : /** Get the remote endpoint of the socket.
940 :
941 : Returns the address of the connected peer.
942 :
943 : @return The remote endpoint, or a default endpoint if
944 : not connected.
945 : */
946 : corosio::local_endpoint remote_endpoint() const noexcept;
947 :
948 : protected:
949 : /// Default-construct (for derived types).
950 : local_datagram_socket() noexcept = default;
951 :
952 : /// Construct from a pre-built handle.
953 30 : explicit local_datagram_socket(handle h) noexcept : io_object(std::move(h))
954 : {
955 30 : }
956 :
957 : private:
958 : [[nodiscard]] std::error_code
959 : open_for_family(int family, int type, int protocol) noexcept;
960 :
961 1858 : inline implementation& get() const noexcept
962 : {
963 1858 : return *static_cast<implementation*>(h_.get());
964 : }
965 : };
966 :
967 : } // namespace boost::corosio
968 :
969 : #endif // BOOST_COROSIO_POSIX
970 :
971 : #endif // BOOST_COROSIO_LOCAL_DATAGRAM_SOCKET_HPP
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