xref: /freebsd/sys/kern/sys_socket.c (revision 732a02b4e77866604a120a275c082bb6221bd2ff)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1982, 1986, 1990, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  *
31  *	@(#)sys_socket.c	8.1 (Berkeley) 6/10/93
32  */
33 
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD$");
36 
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/aio.h>
40 #include <sys/domain.h>
41 #include <sys/file.h>
42 #include <sys/filedesc.h>
43 #include <sys/kernel.h>
44 #include <sys/kthread.h>
45 #include <sys/malloc.h>
46 #include <sys/proc.h>
47 #include <sys/protosw.h>
48 #include <sys/sigio.h>
49 #include <sys/signal.h>
50 #include <sys/signalvar.h>
51 #include <sys/socket.h>
52 #include <sys/socketvar.h>
53 #include <sys/filio.h>			/* XXX */
54 #include <sys/sockio.h>
55 #include <sys/stat.h>
56 #include <sys/sysctl.h>
57 #include <sys/sysproto.h>
58 #include <sys/taskqueue.h>
59 #include <sys/uio.h>
60 #include <sys/ucred.h>
61 #include <sys/un.h>
62 #include <sys/unpcb.h>
63 #include <sys/user.h>
64 
65 #include <net/if.h>
66 #include <net/if_var.h>
67 #include <net/route.h>
68 #include <net/vnet.h>
69 
70 #include <netinet/in.h>
71 #include <netinet/in_pcb.h>
72 
73 #include <security/mac/mac_framework.h>
74 
75 #include <vm/vm.h>
76 #include <vm/pmap.h>
77 #include <vm/vm_extern.h>
78 #include <vm/vm_map.h>
79 
80 static SYSCTL_NODE(_kern_ipc, OID_AUTO, aio, CTLFLAG_RD | CTLFLAG_MPSAFE, NULL,
81     "socket AIO stats");
82 
83 static int empty_results;
84 SYSCTL_INT(_kern_ipc_aio, OID_AUTO, empty_results, CTLFLAG_RD, &empty_results,
85     0, "socket operation returned EAGAIN");
86 
87 static int empty_retries;
88 SYSCTL_INT(_kern_ipc_aio, OID_AUTO, empty_retries, CTLFLAG_RD, &empty_retries,
89     0, "socket operation retries");
90 
91 static fo_rdwr_t soo_read;
92 static fo_rdwr_t soo_write;
93 static fo_ioctl_t soo_ioctl;
94 static fo_poll_t soo_poll;
95 extern fo_kqfilter_t soo_kqfilter;
96 static fo_stat_t soo_stat;
97 static fo_close_t soo_close;
98 static fo_fill_kinfo_t soo_fill_kinfo;
99 static fo_aio_queue_t soo_aio_queue;
100 
101 static void	soo_aio_cancel(struct kaiocb *job);
102 
103 struct fileops	socketops = {
104 	.fo_read = soo_read,
105 	.fo_write = soo_write,
106 	.fo_truncate = invfo_truncate,
107 	.fo_ioctl = soo_ioctl,
108 	.fo_poll = soo_poll,
109 	.fo_kqfilter = soo_kqfilter,
110 	.fo_stat = soo_stat,
111 	.fo_close = soo_close,
112 	.fo_chmod = invfo_chmod,
113 	.fo_chown = invfo_chown,
114 	.fo_sendfile = invfo_sendfile,
115 	.fo_fill_kinfo = soo_fill_kinfo,
116 	.fo_aio_queue = soo_aio_queue,
117 	.fo_flags = DFLAG_PASSABLE
118 };
119 
120 static int
121 soo_read(struct file *fp, struct uio *uio, struct ucred *active_cred,
122     int flags, struct thread *td)
123 {
124 	struct socket *so = fp->f_data;
125 	int error;
126 
127 #ifdef MAC
128 	error = mac_socket_check_receive(active_cred, so);
129 	if (error)
130 		return (error);
131 #endif
132 	error = soreceive(so, 0, uio, 0, 0, 0);
133 	return (error);
134 }
135 
136 static int
137 soo_write(struct file *fp, struct uio *uio, struct ucred *active_cred,
138     int flags, struct thread *td)
139 {
140 	struct socket *so = fp->f_data;
141 	int error;
142 
143 #ifdef MAC
144 	error = mac_socket_check_send(active_cred, so);
145 	if (error)
146 		return (error);
147 #endif
148 	error = sosend(so, 0, uio, 0, 0, 0, uio->uio_td);
149 	if (error == EPIPE && (so->so_options & SO_NOSIGPIPE) == 0) {
150 		PROC_LOCK(uio->uio_td->td_proc);
151 		tdsignal(uio->uio_td, SIGPIPE);
152 		PROC_UNLOCK(uio->uio_td->td_proc);
153 	}
154 	return (error);
155 }
156 
157 static int
158 soo_ioctl(struct file *fp, u_long cmd, void *data, struct ucred *active_cred,
159     struct thread *td)
160 {
161 	struct socket *so = fp->f_data;
162 	int error = 0;
163 
164 	switch (cmd) {
165 	case FIONBIO:
166 		SOCK_LOCK(so);
167 		if (*(int *)data)
168 			so->so_state |= SS_NBIO;
169 		else
170 			so->so_state &= ~SS_NBIO;
171 		SOCK_UNLOCK(so);
172 		break;
173 
174 	case FIOASYNC:
175 		if (*(int *)data) {
176 			SOCK_LOCK(so);
177 			so->so_state |= SS_ASYNC;
178 			if (SOLISTENING(so)) {
179 				so->sol_sbrcv_flags |= SB_ASYNC;
180 				so->sol_sbsnd_flags |= SB_ASYNC;
181 			} else {
182 				SOCKBUF_LOCK(&so->so_rcv);
183 				so->so_rcv.sb_flags |= SB_ASYNC;
184 				SOCKBUF_UNLOCK(&so->so_rcv);
185 				SOCKBUF_LOCK(&so->so_snd);
186 				so->so_snd.sb_flags |= SB_ASYNC;
187 				SOCKBUF_UNLOCK(&so->so_snd);
188 			}
189 			SOCK_UNLOCK(so);
190 		} else {
191 			SOCK_LOCK(so);
192 			so->so_state &= ~SS_ASYNC;
193 			if (SOLISTENING(so)) {
194 				so->sol_sbrcv_flags &= ~SB_ASYNC;
195 				so->sol_sbsnd_flags &= ~SB_ASYNC;
196 			} else {
197 				SOCKBUF_LOCK(&so->so_rcv);
198 				so->so_rcv.sb_flags &= ~SB_ASYNC;
199 				SOCKBUF_UNLOCK(&so->so_rcv);
200 				SOCKBUF_LOCK(&so->so_snd);
201 				so->so_snd.sb_flags &= ~SB_ASYNC;
202 				SOCKBUF_UNLOCK(&so->so_snd);
203 			}
204 			SOCK_UNLOCK(so);
205 		}
206 		break;
207 
208 	case FIONREAD:
209 		/* Unlocked read. */
210 		*(int *)data = sbavail(&so->so_rcv);
211 		break;
212 
213 	case FIONWRITE:
214 		/* Unlocked read. */
215 		*(int *)data = sbavail(&so->so_snd);
216 		break;
217 
218 	case FIONSPACE:
219 		/* Unlocked read. */
220 		if ((so->so_snd.sb_hiwat < sbused(&so->so_snd)) ||
221 		    (so->so_snd.sb_mbmax < so->so_snd.sb_mbcnt))
222 			*(int *)data = 0;
223 		else
224 			*(int *)data = sbspace(&so->so_snd);
225 		break;
226 
227 	case FIOSETOWN:
228 		error = fsetown(*(int *)data, &so->so_sigio);
229 		break;
230 
231 	case FIOGETOWN:
232 		*(int *)data = fgetown(&so->so_sigio);
233 		break;
234 
235 	case SIOCSPGRP:
236 		error = fsetown(-(*(int *)data), &so->so_sigio);
237 		break;
238 
239 	case SIOCGPGRP:
240 		*(int *)data = -fgetown(&so->so_sigio);
241 		break;
242 
243 	case SIOCATMARK:
244 		/* Unlocked read. */
245 		*(int *)data = (so->so_rcv.sb_state & SBS_RCVATMARK) != 0;
246 		break;
247 	default:
248 		/*
249 		 * Interface/routing/protocol specific ioctls: interface and
250 		 * routing ioctls should have a different entry since a
251 		 * socket is unnecessary.
252 		 */
253 		if (IOCGROUP(cmd) == 'i')
254 			error = ifioctl(so, cmd, data, td);
255 		else if (IOCGROUP(cmd) == 'r') {
256 			CURVNET_SET(so->so_vnet);
257 			error = rtioctl_fib(cmd, data, so->so_fibnum);
258 			CURVNET_RESTORE();
259 		} else {
260 			CURVNET_SET(so->so_vnet);
261 			error = ((*so->so_proto->pr_usrreqs->pru_control)
262 			    (so, cmd, data, 0, td));
263 			CURVNET_RESTORE();
264 		}
265 		break;
266 	}
267 	return (error);
268 }
269 
270 static int
271 soo_poll(struct file *fp, int events, struct ucred *active_cred,
272     struct thread *td)
273 {
274 	struct socket *so = fp->f_data;
275 #ifdef MAC
276 	int error;
277 
278 	error = mac_socket_check_poll(active_cred, so);
279 	if (error)
280 		return (error);
281 #endif
282 	return (sopoll(so, events, fp->f_cred, td));
283 }
284 
285 static int
286 soo_stat(struct file *fp, struct stat *ub, struct ucred *active_cred,
287     struct thread *td)
288 {
289 	struct socket *so = fp->f_data;
290 	int error;
291 
292 	bzero((caddr_t)ub, sizeof (*ub));
293 	ub->st_mode = S_IFSOCK;
294 #ifdef MAC
295 	error = mac_socket_check_stat(active_cred, so);
296 	if (error)
297 		return (error);
298 #endif
299 	SOCK_LOCK(so);
300 	if (!SOLISTENING(so)) {
301 		struct sockbuf *sb;
302 
303 		/*
304 		 * If SBS_CANTRCVMORE is set, but there's still data left
305 		 * in the receive buffer, the socket is still readable.
306 		 */
307 		sb = &so->so_rcv;
308 		SOCKBUF_LOCK(sb);
309 		if ((sb->sb_state & SBS_CANTRCVMORE) == 0 || sbavail(sb))
310 			ub->st_mode |= S_IRUSR | S_IRGRP | S_IROTH;
311 		ub->st_size = sbavail(sb) - sb->sb_ctl;
312 		SOCKBUF_UNLOCK(sb);
313 
314 		sb = &so->so_snd;
315 		SOCKBUF_LOCK(sb);
316 		if ((sb->sb_state & SBS_CANTSENDMORE) == 0)
317 			ub->st_mode |= S_IWUSR | S_IWGRP | S_IWOTH;
318 		SOCKBUF_UNLOCK(sb);
319 	}
320 	ub->st_uid = so->so_cred->cr_uid;
321 	ub->st_gid = so->so_cred->cr_gid;
322 	error = so->so_proto->pr_usrreqs->pru_sense(so, ub);
323 	SOCK_UNLOCK(so);
324 	return (error);
325 }
326 
327 /*
328  * API socket close on file pointer.  We call soclose() to close the socket
329  * (including initiating closing protocols).  soclose() will sorele() the
330  * file reference but the actual socket will not go away until the socket's
331  * ref count hits 0.
332  */
333 static int
334 soo_close(struct file *fp, struct thread *td)
335 {
336 	int error = 0;
337 	struct socket *so;
338 
339 	so = fp->f_data;
340 	fp->f_ops = &badfileops;
341 	fp->f_data = NULL;
342 
343 	if (so)
344 		error = soclose(so);
345 	return (error);
346 }
347 
348 static int
349 soo_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp)
350 {
351 	struct sockaddr *sa;
352 	struct inpcb *inpcb;
353 	struct unpcb *unpcb;
354 	struct socket *so;
355 	int error;
356 
357 	kif->kf_type = KF_TYPE_SOCKET;
358 	so = fp->f_data;
359 	CURVNET_SET(so->so_vnet);
360 	kif->kf_un.kf_sock.kf_sock_domain0 =
361 	    so->so_proto->pr_domain->dom_family;
362 	kif->kf_un.kf_sock.kf_sock_type0 = so->so_type;
363 	kif->kf_un.kf_sock.kf_sock_protocol0 = so->so_proto->pr_protocol;
364 	kif->kf_un.kf_sock.kf_sock_pcb = (uintptr_t)so->so_pcb;
365 	switch (kif->kf_un.kf_sock.kf_sock_domain0) {
366 	case AF_INET:
367 	case AF_INET6:
368 		if (kif->kf_un.kf_sock.kf_sock_protocol0 == IPPROTO_TCP) {
369 			if (so->so_pcb != NULL) {
370 				inpcb = (struct inpcb *)(so->so_pcb);
371 				kif->kf_un.kf_sock.kf_sock_inpcb =
372 				    (uintptr_t)inpcb->inp_ppcb;
373 				kif->kf_un.kf_sock.kf_sock_sendq =
374 				    sbused(&so->so_snd);
375 				kif->kf_un.kf_sock.kf_sock_recvq =
376 				    sbused(&so->so_rcv);
377 			}
378 		}
379 		break;
380 	case AF_UNIX:
381 		if (so->so_pcb != NULL) {
382 			unpcb = (struct unpcb *)(so->so_pcb);
383 			if (unpcb->unp_conn) {
384 				kif->kf_un.kf_sock.kf_sock_unpconn =
385 				    (uintptr_t)unpcb->unp_conn;
386 				kif->kf_un.kf_sock.kf_sock_rcv_sb_state =
387 				    so->so_rcv.sb_state;
388 				kif->kf_un.kf_sock.kf_sock_snd_sb_state =
389 				    so->so_snd.sb_state;
390 				kif->kf_un.kf_sock.kf_sock_sendq =
391 				    sbused(&so->so_snd);
392 				kif->kf_un.kf_sock.kf_sock_recvq =
393 				    sbused(&so->so_rcv);
394 			}
395 		}
396 		break;
397 	}
398 	error = so->so_proto->pr_usrreqs->pru_sockaddr(so, &sa);
399 	if (error == 0 &&
400 	    sa->sa_len <= sizeof(kif->kf_un.kf_sock.kf_sa_local)) {
401 		bcopy(sa, &kif->kf_un.kf_sock.kf_sa_local, sa->sa_len);
402 		free(sa, M_SONAME);
403 	}
404 	error = so->so_proto->pr_usrreqs->pru_peeraddr(so, &sa);
405 	if (error == 0 &&
406 	    sa->sa_len <= sizeof(kif->kf_un.kf_sock.kf_sa_peer)) {
407 		bcopy(sa, &kif->kf_un.kf_sock.kf_sa_peer, sa->sa_len);
408 		free(sa, M_SONAME);
409 	}
410 	strncpy(kif->kf_path, so->so_proto->pr_domain->dom_name,
411 	    sizeof(kif->kf_path));
412 	CURVNET_RESTORE();
413 	return (0);
414 }
415 
416 /*
417  * Use the 'backend3' field in AIO jobs to store the amount of data
418  * completed by the AIO job so far.
419  */
420 #define	aio_done	backend3
421 
422 static STAILQ_HEAD(, task) soaio_jobs;
423 static struct mtx soaio_jobs_lock;
424 static struct task soaio_kproc_task;
425 static int soaio_starting, soaio_idle, soaio_queued;
426 static struct unrhdr *soaio_kproc_unr;
427 
428 static int soaio_max_procs = MAX_AIO_PROCS;
429 SYSCTL_INT(_kern_ipc_aio, OID_AUTO, max_procs, CTLFLAG_RW, &soaio_max_procs, 0,
430     "Maximum number of kernel processes to use for async socket IO");
431 
432 static int soaio_num_procs;
433 SYSCTL_INT(_kern_ipc_aio, OID_AUTO, num_procs, CTLFLAG_RD, &soaio_num_procs, 0,
434     "Number of active kernel processes for async socket IO");
435 
436 static int soaio_target_procs = TARGET_AIO_PROCS;
437 SYSCTL_INT(_kern_ipc_aio, OID_AUTO, target_procs, CTLFLAG_RD,
438     &soaio_target_procs, 0,
439     "Preferred number of ready kernel processes for async socket IO");
440 
441 static int soaio_lifetime;
442 SYSCTL_INT(_kern_ipc_aio, OID_AUTO, lifetime, CTLFLAG_RW, &soaio_lifetime, 0,
443     "Maximum lifetime for idle aiod");
444 
445 static void
446 soaio_kproc_loop(void *arg)
447 {
448 	struct proc *p;
449 	struct vmspace *myvm;
450 	struct task *task;
451 	int error, id, pending;
452 
453 	id = (intptr_t)arg;
454 
455 	/*
456 	 * Grab an extra reference on the daemon's vmspace so that it
457 	 * doesn't get freed by jobs that switch to a different
458 	 * vmspace.
459 	 */
460 	p = curproc;
461 	myvm = vmspace_acquire_ref(p);
462 
463 	mtx_lock(&soaio_jobs_lock);
464 	MPASS(soaio_starting > 0);
465 	soaio_starting--;
466 	for (;;) {
467 		while (!STAILQ_EMPTY(&soaio_jobs)) {
468 			task = STAILQ_FIRST(&soaio_jobs);
469 			STAILQ_REMOVE_HEAD(&soaio_jobs, ta_link);
470 			soaio_queued--;
471 			pending = task->ta_pending;
472 			task->ta_pending = 0;
473 			mtx_unlock(&soaio_jobs_lock);
474 
475 			task->ta_func(task->ta_context, pending);
476 
477 			mtx_lock(&soaio_jobs_lock);
478 		}
479 		MPASS(soaio_queued == 0);
480 
481 		if (p->p_vmspace != myvm) {
482 			mtx_unlock(&soaio_jobs_lock);
483 			vmspace_switch_aio(myvm);
484 			mtx_lock(&soaio_jobs_lock);
485 			continue;
486 		}
487 
488 		soaio_idle++;
489 		error = mtx_sleep(&soaio_idle, &soaio_jobs_lock, 0, "-",
490 		    soaio_lifetime);
491 		soaio_idle--;
492 		if (error == EWOULDBLOCK && STAILQ_EMPTY(&soaio_jobs) &&
493 		    soaio_num_procs > soaio_target_procs)
494 			break;
495 	}
496 	soaio_num_procs--;
497 	mtx_unlock(&soaio_jobs_lock);
498 	free_unr(soaio_kproc_unr, id);
499 	kproc_exit(0);
500 }
501 
502 static void
503 soaio_kproc_create(void *context, int pending)
504 {
505 	struct proc *p;
506 	int error, id;
507 
508 	mtx_lock(&soaio_jobs_lock);
509 	for (;;) {
510 		if (soaio_num_procs < soaio_target_procs) {
511 			/* Must create */
512 		} else if (soaio_num_procs >= soaio_max_procs) {
513 			/*
514 			 * Hit the limit on kernel processes, don't
515 			 * create another one.
516 			 */
517 			break;
518 		} else if (soaio_queued <= soaio_idle + soaio_starting) {
519 			/*
520 			 * No more AIO jobs waiting for a process to be
521 			 * created, so stop.
522 			 */
523 			break;
524 		}
525 		soaio_starting++;
526 		mtx_unlock(&soaio_jobs_lock);
527 
528 		id = alloc_unr(soaio_kproc_unr);
529 		error = kproc_create(soaio_kproc_loop, (void *)(intptr_t)id,
530 		    &p, 0, 0, "soaiod%d", id);
531 		if (error != 0) {
532 			free_unr(soaio_kproc_unr, id);
533 			mtx_lock(&soaio_jobs_lock);
534 			soaio_starting--;
535 			break;
536 		}
537 
538 		mtx_lock(&soaio_jobs_lock);
539 		soaio_num_procs++;
540 	}
541 	mtx_unlock(&soaio_jobs_lock);
542 }
543 
544 void
545 soaio_enqueue(struct task *task)
546 {
547 
548 	mtx_lock(&soaio_jobs_lock);
549 	MPASS(task->ta_pending == 0);
550 	task->ta_pending++;
551 	STAILQ_INSERT_TAIL(&soaio_jobs, task, ta_link);
552 	soaio_queued++;
553 	if (soaio_queued <= soaio_idle)
554 		wakeup_one(&soaio_idle);
555 	else if (soaio_num_procs < soaio_max_procs)
556 		taskqueue_enqueue(taskqueue_thread, &soaio_kproc_task);
557 	mtx_unlock(&soaio_jobs_lock);
558 }
559 
560 static void
561 soaio_init(void)
562 {
563 
564 	soaio_lifetime = AIOD_LIFETIME_DEFAULT;
565 	STAILQ_INIT(&soaio_jobs);
566 	mtx_init(&soaio_jobs_lock, "soaio jobs", NULL, MTX_DEF);
567 	soaio_kproc_unr = new_unrhdr(1, INT_MAX, NULL);
568 	TASK_INIT(&soaio_kproc_task, 0, soaio_kproc_create, NULL);
569 	if (soaio_target_procs > 0)
570 		taskqueue_enqueue(taskqueue_thread, &soaio_kproc_task);
571 }
572 SYSINIT(soaio, SI_SUB_VFS, SI_ORDER_ANY, soaio_init, NULL);
573 
574 static __inline int
575 soaio_ready(struct socket *so, struct sockbuf *sb)
576 {
577 	return (sb == &so->so_rcv ? soreadable(so) : sowriteable(so));
578 }
579 
580 static void
581 soaio_process_job(struct socket *so, struct sockbuf *sb, struct kaiocb *job)
582 {
583 	struct ucred *td_savedcred;
584 	struct thread *td;
585 	struct file *fp;
586 	struct uio uio;
587 	struct iovec iov;
588 	size_t cnt, done;
589 	long ru_before;
590 	int error, flags;
591 
592 	SOCKBUF_UNLOCK(sb);
593 	aio_switch_vmspace(job);
594 	td = curthread;
595 	fp = job->fd_file;
596 retry:
597 	td_savedcred = td->td_ucred;
598 	td->td_ucred = job->cred;
599 
600 	done = job->aio_done;
601 	cnt = job->uaiocb.aio_nbytes - done;
602 	iov.iov_base = (void *)((uintptr_t)job->uaiocb.aio_buf + done);
603 	iov.iov_len = cnt;
604 	uio.uio_iov = &iov;
605 	uio.uio_iovcnt = 1;
606 	uio.uio_offset = 0;
607 	uio.uio_resid = cnt;
608 	uio.uio_segflg = UIO_USERSPACE;
609 	uio.uio_td = td;
610 	flags = MSG_NBIO;
611 
612 	/*
613 	 * For resource usage accounting, only count a completed request
614 	 * as a single message to avoid counting multiple calls to
615 	 * sosend/soreceive on a blocking socket.
616 	 */
617 
618 	if (sb == &so->so_rcv) {
619 		uio.uio_rw = UIO_READ;
620 		ru_before = td->td_ru.ru_msgrcv;
621 #ifdef MAC
622 		error = mac_socket_check_receive(fp->f_cred, so);
623 		if (error == 0)
624 
625 #endif
626 			error = soreceive(so, NULL, &uio, NULL, NULL, &flags);
627 		if (td->td_ru.ru_msgrcv != ru_before)
628 			job->msgrcv = 1;
629 	} else {
630 		if (!TAILQ_EMPTY(&sb->sb_aiojobq))
631 			flags |= MSG_MORETOCOME;
632 		uio.uio_rw = UIO_WRITE;
633 		ru_before = td->td_ru.ru_msgsnd;
634 #ifdef MAC
635 		error = mac_socket_check_send(fp->f_cred, so);
636 		if (error == 0)
637 #endif
638 			error = sosend(so, NULL, &uio, NULL, NULL, flags, td);
639 		if (td->td_ru.ru_msgsnd != ru_before)
640 			job->msgsnd = 1;
641 		if (error == EPIPE && (so->so_options & SO_NOSIGPIPE) == 0) {
642 			PROC_LOCK(job->userproc);
643 			kern_psignal(job->userproc, SIGPIPE);
644 			PROC_UNLOCK(job->userproc);
645 		}
646 	}
647 
648 	done += cnt - uio.uio_resid;
649 	job->aio_done = done;
650 	td->td_ucred = td_savedcred;
651 
652 	if (error == EWOULDBLOCK) {
653 		/*
654 		 * The request was either partially completed or not
655 		 * completed at all due to racing with a read() or
656 		 * write() on the socket.  If the socket is
657 		 * non-blocking, return with any partial completion.
658 		 * If the socket is blocking or if no progress has
659 		 * been made, requeue this request at the head of the
660 		 * queue to try again when the socket is ready.
661 		 */
662 		MPASS(done != job->uaiocb.aio_nbytes);
663 		SOCKBUF_LOCK(sb);
664 		if (done == 0 || !(so->so_state & SS_NBIO)) {
665 			empty_results++;
666 			if (soaio_ready(so, sb)) {
667 				empty_retries++;
668 				SOCKBUF_UNLOCK(sb);
669 				goto retry;
670 			}
671 
672 			if (!aio_set_cancel_function(job, soo_aio_cancel)) {
673 				SOCKBUF_UNLOCK(sb);
674 				if (done != 0)
675 					aio_complete(job, done, 0);
676 				else
677 					aio_cancel(job);
678 				SOCKBUF_LOCK(sb);
679 			} else {
680 				TAILQ_INSERT_HEAD(&sb->sb_aiojobq, job, list);
681 			}
682 			return;
683 		}
684 		SOCKBUF_UNLOCK(sb);
685 	}
686 	if (done != 0 && (error == ERESTART || error == EINTR ||
687 	    error == EWOULDBLOCK))
688 		error = 0;
689 	if (error)
690 		aio_complete(job, -1, error);
691 	else
692 		aio_complete(job, done, 0);
693 	SOCKBUF_LOCK(sb);
694 }
695 
696 static void
697 soaio_process_sb(struct socket *so, struct sockbuf *sb)
698 {
699 	struct kaiocb *job;
700 
701 	CURVNET_SET(so->so_vnet);
702 	SOCKBUF_LOCK(sb);
703 	while (!TAILQ_EMPTY(&sb->sb_aiojobq) && soaio_ready(so, sb)) {
704 		job = TAILQ_FIRST(&sb->sb_aiojobq);
705 		TAILQ_REMOVE(&sb->sb_aiojobq, job, list);
706 		if (!aio_clear_cancel_function(job))
707 			continue;
708 
709 		soaio_process_job(so, sb, job);
710 	}
711 
712 	/*
713 	 * If there are still pending requests, the socket must not be
714 	 * ready so set SB_AIO to request a wakeup when the socket
715 	 * becomes ready.
716 	 */
717 	if (!TAILQ_EMPTY(&sb->sb_aiojobq))
718 		sb->sb_flags |= SB_AIO;
719 	sb->sb_flags &= ~SB_AIO_RUNNING;
720 	SOCKBUF_UNLOCK(sb);
721 
722 	SOCK_LOCK(so);
723 	sorele(so);
724 	CURVNET_RESTORE();
725 }
726 
727 void
728 soaio_rcv(void *context, int pending)
729 {
730 	struct socket *so;
731 
732 	so = context;
733 	soaio_process_sb(so, &so->so_rcv);
734 }
735 
736 void
737 soaio_snd(void *context, int pending)
738 {
739 	struct socket *so;
740 
741 	so = context;
742 	soaio_process_sb(so, &so->so_snd);
743 }
744 
745 void
746 sowakeup_aio(struct socket *so, struct sockbuf *sb)
747 {
748 
749 	SOCKBUF_LOCK_ASSERT(sb);
750 	sb->sb_flags &= ~SB_AIO;
751 	if (sb->sb_flags & SB_AIO_RUNNING)
752 		return;
753 	sb->sb_flags |= SB_AIO_RUNNING;
754 	soref(so);
755 	soaio_enqueue(&sb->sb_aiotask);
756 }
757 
758 static void
759 soo_aio_cancel(struct kaiocb *job)
760 {
761 	struct socket *so;
762 	struct sockbuf *sb;
763 	long done;
764 	int opcode;
765 
766 	so = job->fd_file->f_data;
767 	opcode = job->uaiocb.aio_lio_opcode;
768 	if (opcode == LIO_READ)
769 		sb = &so->so_rcv;
770 	else {
771 		MPASS(opcode == LIO_WRITE);
772 		sb = &so->so_snd;
773 	}
774 
775 	SOCKBUF_LOCK(sb);
776 	if (!aio_cancel_cleared(job))
777 		TAILQ_REMOVE(&sb->sb_aiojobq, job, list);
778 	if (TAILQ_EMPTY(&sb->sb_aiojobq))
779 		sb->sb_flags &= ~SB_AIO;
780 	SOCKBUF_UNLOCK(sb);
781 
782 	done = job->aio_done;
783 	if (done != 0)
784 		aio_complete(job, done, 0);
785 	else
786 		aio_cancel(job);
787 }
788 
789 static int
790 soo_aio_queue(struct file *fp, struct kaiocb *job)
791 {
792 	struct socket *so;
793 	struct sockbuf *sb;
794 	int error;
795 
796 	so = fp->f_data;
797 	error = (*so->so_proto->pr_usrreqs->pru_aio_queue)(so, job);
798 	if (error == 0)
799 		return (0);
800 
801 	switch (job->uaiocb.aio_lio_opcode) {
802 	case LIO_READ:
803 		sb = &so->so_rcv;
804 		break;
805 	case LIO_WRITE:
806 		sb = &so->so_snd;
807 		break;
808 	default:
809 		return (EINVAL);
810 	}
811 
812 	SOCKBUF_LOCK(sb);
813 	if (!aio_set_cancel_function(job, soo_aio_cancel))
814 		panic("new job was cancelled");
815 	TAILQ_INSERT_TAIL(&sb->sb_aiojobq, job, list);
816 	if (!(sb->sb_flags & SB_AIO_RUNNING)) {
817 		if (soaio_ready(so, sb))
818 			sowakeup_aio(so, sb);
819 		else
820 			sb->sb_flags |= SB_AIO;
821 	}
822 	SOCKBUF_UNLOCK(sb);
823 	return (0);
824 }
825