xref: /illumos-gate/usr/src/uts/common/fs/sockfs/sockcommon_subr.c (revision 48f21d36693650e32c51fc8474dca1acc9b7376c)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #include <sys/types.h>
28 #include <sys/param.h>
29 #include <sys/signal.h>
30 #include <sys/cmn_err.h>
31 
32 #include <sys/stropts.h>
33 #include <sys/socket.h>
34 #include <sys/socketvar.h>
35 #include <sys/sockio.h>
36 #include <sys/strsubr.h>
37 #include <sys/strsun.h>
38 #include <sys/atomic.h>
39 #include <sys/tihdr.h>
40 
41 #include <fs/sockfs/sockcommon.h>
42 #include <fs/sockfs/socktpi.h>
43 #include <fs/sockfs/sodirect.h>
44 #include <sys/ddi.h>
45 #include <inet/ip.h>
46 #include <sys/time.h>
47 #include <sys/cmn_err.h>
48 
49 #ifdef SOCK_TEST
50 extern int do_useracc;
51 extern clock_t sock_test_timelimit;
52 #endif /* SOCK_TEST */
53 
54 #define	MBLK_PULL_LEN 64
55 uint32_t so_mblk_pull_len = MBLK_PULL_LEN;
56 
57 #ifdef DEBUG
58 boolean_t so_debug_length = B_FALSE;
59 static boolean_t so_check_length(sonode_t *so);
60 #endif
61 
62 int
63 so_acceptq_enqueue_locked(struct sonode *so, struct sonode *nso)
64 {
65 	ASSERT(MUTEX_HELD(&so->so_acceptq_lock));
66 	ASSERT(nso->so_acceptq_next == NULL);
67 
68 	*so->so_acceptq_tail = nso;
69 	so->so_acceptq_tail = &nso->so_acceptq_next;
70 	so->so_acceptq_len++;
71 
72 	/* Wakeup a single consumer */
73 	cv_signal(&so->so_acceptq_cv);
74 
75 	return (so->so_acceptq_len);
76 }
77 
78 /*
79  * int so_acceptq_enqueue(struct sonode *so, struct sonode *nso)
80  *
81  * Enqueue an incoming connection on a listening socket.
82  *
83  * Arguments:
84  *   so	  - listening socket
85  *   nso  - new connection
86  *
87  * Returns:
88  *   Number of queued connections, including the new connection
89  */
90 int
91 so_acceptq_enqueue(struct sonode *so, struct sonode *nso)
92 {
93 	int conns;
94 
95 	mutex_enter(&so->so_acceptq_lock);
96 	conns = so_acceptq_enqueue_locked(so, nso);
97 	mutex_exit(&so->so_acceptq_lock);
98 
99 	return (conns);
100 }
101 
102 static int
103 so_acceptq_dequeue_locked(struct sonode *so, boolean_t dontblock,
104     struct sonode **nsop)
105 {
106 	struct sonode *nso = NULL;
107 
108 	*nsop = NULL;
109 	ASSERT(MUTEX_HELD(&so->so_acceptq_lock));
110 	while ((nso = so->so_acceptq_head) == NULL) {
111 		/*
112 		 * No need to check so_error here, because it is not
113 		 * possible for a listening socket to be reset or otherwise
114 		 * disconnected.
115 		 *
116 		 * So now we just need check if it's ok to wait.
117 		 */
118 		if (dontblock)
119 			return (EWOULDBLOCK);
120 		if (so->so_state & (SS_CLOSING | SS_FALLBACK_PENDING))
121 			return (EINTR);
122 
123 		if (cv_wait_sig_swap(&so->so_acceptq_cv,
124 		    &so->so_acceptq_lock) == 0)
125 			return (EINTR);
126 	}
127 
128 	ASSERT(nso != NULL);
129 	so->so_acceptq_head = nso->so_acceptq_next;
130 	nso->so_acceptq_next = NULL;
131 
132 	if (so->so_acceptq_head == NULL) {
133 		ASSERT(so->so_acceptq_tail == &nso->so_acceptq_next);
134 		so->so_acceptq_tail = &so->so_acceptq_head;
135 	}
136 	ASSERT(so->so_acceptq_len > 0);
137 	--so->so_acceptq_len;
138 
139 	*nsop = nso;
140 
141 	return (0);
142 }
143 
144 /*
145  * int so_acceptq_dequeue(struct sonode *, boolean_t, struct sonode **)
146  *
147  * Pulls a connection off of the accept queue.
148  *
149  * Arguments:
150  *   so	       - listening socket
151  *   dontblock - indicate whether it's ok to sleep if there are no
152  *		 connections on the queue
153  *   nsop      - Value-return argument
154  *
155  * Return values:
156  *   0 when a connection is successfully dequeued, in which case nsop
157  *   is set to point to the new connection. Upon failure a non-zero
158  *   value is returned, and the value of nsop is set to NULL.
159  *
160  * Note:
161  *   so_acceptq_dequeue() may return prematurly if the socket is falling
162  *   back to TPI.
163  */
164 int
165 so_acceptq_dequeue(struct sonode *so, boolean_t dontblock,
166     struct sonode **nsop)
167 {
168 	int error;
169 
170 	mutex_enter(&so->so_acceptq_lock);
171 	error = so_acceptq_dequeue_locked(so, dontblock, nsop);
172 	mutex_exit(&so->so_acceptq_lock);
173 
174 	return (error);
175 }
176 
177 /*
178  * void so_acceptq_flush(struct sonode *so)
179  *
180  * Removes all pending connections from a listening socket, and
181  * frees the associated resources.
182  *
183  * Arguments
184  *   so	    - listening socket
185  *
186  * Return values:
187  *   None.
188  *
189  * Note:
190  *   The caller has to ensure that no calls to so_acceptq_enqueue() or
191  *   so_acceptq_dequeue() occur while the accept queue is being flushed.
192  *   So either the socket needs to be in a state where no operations
193  *   would come in, or so_lock needs to be obtained.
194  */
195 void
196 so_acceptq_flush(struct sonode *so)
197 {
198 	struct sonode *nso;
199 
200 	nso = so->so_acceptq_head;
201 
202 	while (nso != NULL) {
203 		struct sonode *nnso = NULL;
204 
205 		nnso = nso->so_acceptq_next;
206 		nso->so_acceptq_next = NULL;
207 		/*
208 		 * Since the socket is on the accept queue, there can
209 		 * only be one reference. We drop the reference and
210 		 * just blow off the socket.
211 		 */
212 		ASSERT(nso->so_count == 1);
213 		nso->so_count--;
214 		socket_destroy(nso);
215 		nso = nnso;
216 	}
217 
218 	so->so_acceptq_head = NULL;
219 	so->so_acceptq_tail = &so->so_acceptq_head;
220 	so->so_acceptq_len = 0;
221 }
222 
223 int
224 so_wait_connected_locked(struct sonode *so, boolean_t nonblock,
225     sock_connid_t id)
226 {
227 	ASSERT(MUTEX_HELD(&so->so_lock));
228 
229 	/*
230 	 * The protocol has notified us that a connection attempt is being
231 	 * made, so before we wait for a notification to arrive we must
232 	 * clear out any errors associated with earlier connection attempts.
233 	 */
234 	if (so->so_error != 0 && SOCK_CONNID_LT(so->so_proto_connid, id))
235 		so->so_error = 0;
236 
237 	while (SOCK_CONNID_LT(so->so_proto_connid, id)) {
238 		if (nonblock)
239 			return (EINPROGRESS);
240 
241 		if (so->so_state & (SS_CLOSING | SS_FALLBACK_PENDING))
242 			return (EINTR);
243 
244 		if (cv_wait_sig_swap(&so->so_state_cv, &so->so_lock) == 0)
245 			return (EINTR);
246 	}
247 
248 	if (so->so_error != 0)
249 		return (sogeterr(so, B_TRUE));
250 	/*
251 	 * Under normal circumstances, so_error should contain an error
252 	 * in case the connect failed. However, it is possible for another
253 	 * thread to come in a consume the error, so generate a sensible
254 	 * error in that case.
255 	 */
256 	if ((so->so_state & SS_ISCONNECTED) == 0)
257 		return (ECONNREFUSED);
258 
259 	return (0);
260 }
261 
262 /*
263  * int so_wait_connected(struct sonode *so, boolean_t nonblock,
264  *    sock_connid_t id)
265  *
266  * Wait until the socket is connected or an error has occured.
267  *
268  * Arguments:
269  *   so	      - socket
270  *   nonblock - indicate whether it's ok to sleep if the connection has
271  *		not yet been established
272  *   gen      - generation number that was returned by the protocol
273  *		when the operation was started
274  *
275  * Returns:
276  *   0 if the connection attempt was successful, or an error indicating why
277  *   the connection attempt failed.
278  */
279 int
280 so_wait_connected(struct sonode *so, boolean_t nonblock, sock_connid_t id)
281 {
282 	int error;
283 
284 	mutex_enter(&so->so_lock);
285 	error = so_wait_connected_locked(so, nonblock, id);
286 	mutex_exit(&so->so_lock);
287 
288 	return (error);
289 }
290 
291 int
292 so_snd_wait_qnotfull_locked(struct sonode *so, boolean_t dontblock)
293 {
294 	int error;
295 
296 	ASSERT(MUTEX_HELD(&so->so_lock));
297 	while (so->so_snd_qfull) {
298 		if (so->so_state & SS_CANTSENDMORE)
299 			return (EPIPE);
300 		if (dontblock)
301 			return (EWOULDBLOCK);
302 
303 		if (so->so_state & (SS_CLOSING | SS_FALLBACK_PENDING))
304 			return (EINTR);
305 
306 		if (so->so_sndtimeo == 0) {
307 			/*
308 			 * Zero means disable timeout.
309 			 */
310 			error = cv_wait_sig(&so->so_snd_cv, &so->so_lock);
311 		} else {
312 			clock_t now;
313 
314 			time_to_wait(&now, so->so_sndtimeo);
315 			error = cv_timedwait_sig(&so->so_snd_cv, &so->so_lock,
316 			    now);
317 		}
318 		if (error == 0)
319 			return (EINTR);
320 		else if (error == -1)
321 			return (EAGAIN);
322 	}
323 	return (0);
324 }
325 
326 /*
327  * int so_wait_sendbuf(struct sonode *so, boolean_t dontblock)
328  *
329  * Wait for the transport to notify us about send buffers becoming
330  * available.
331  */
332 int
333 so_snd_wait_qnotfull(struct sonode *so, boolean_t dontblock)
334 {
335 	int error = 0;
336 
337 	mutex_enter(&so->so_lock);
338 	if (so->so_snd_qfull) {
339 		so->so_snd_wakeup = B_TRUE;
340 		error = so_snd_wait_qnotfull_locked(so, dontblock);
341 		so->so_snd_wakeup = B_FALSE;
342 	}
343 	mutex_exit(&so->so_lock);
344 
345 	return (error);
346 }
347 
348 void
349 so_snd_qfull(struct sonode *so)
350 {
351 	mutex_enter(&so->so_lock);
352 	so->so_snd_qfull = B_TRUE;
353 	mutex_exit(&so->so_lock);
354 }
355 
356 void
357 so_snd_qnotfull(struct sonode *so)
358 {
359 	mutex_enter(&so->so_lock);
360 	so->so_snd_qfull = B_FALSE;
361 	/* wake up everyone waiting for buffers */
362 	cv_broadcast(&so->so_snd_cv);
363 	mutex_exit(&so->so_lock);
364 }
365 
366 /*
367  * Change the process/process group to which SIGIO is sent.
368  */
369 int
370 socket_chgpgrp(struct sonode *so, pid_t pid)
371 {
372 	int error;
373 
374 	ASSERT(MUTEX_HELD(&so->so_lock));
375 	if (pid != 0) {
376 		/*
377 		 * Permissions check by sending signal 0.
378 		 * Note that when kill fails it does a
379 		 * set_errno causing the system call to fail.
380 		 */
381 		error = kill(pid, 0);
382 		if (error != 0) {
383 			return (error);
384 		}
385 	}
386 	so->so_pgrp = pid;
387 	return (0);
388 }
389 
390 
391 /*
392  * Generate a SIGIO, for 'writable' events include siginfo structure,
393  * for read events just send the signal.
394  */
395 /*ARGSUSED*/
396 static void
397 socket_sigproc(proc_t *proc, int event)
398 {
399 	k_siginfo_t info;
400 
401 	ASSERT(event & (SOCKETSIG_WRITE | SOCKETSIG_READ | SOCKETSIG_URG));
402 
403 	if (event & SOCKETSIG_WRITE) {
404 		info.si_signo = SIGPOLL;
405 		info.si_code = POLL_OUT;
406 		info.si_errno = 0;
407 		info.si_fd = 0;
408 		info.si_band = 0;
409 		sigaddq(proc, NULL, &info, KM_NOSLEEP);
410 	}
411 	if (event & SOCKETSIG_READ) {
412 		sigtoproc(proc, NULL, SIGPOLL);
413 	}
414 	if (event & SOCKETSIG_URG) {
415 		sigtoproc(proc, NULL, SIGURG);
416 	}
417 }
418 
419 void
420 socket_sendsig(struct sonode *so, int event)
421 {
422 	proc_t *proc;
423 
424 	ASSERT(MUTEX_HELD(&so->so_lock));
425 
426 	if (so->so_pgrp == 0 || (!(so->so_state & SS_ASYNC) &&
427 	    event != SOCKETSIG_URG)) {
428 		return;
429 	}
430 
431 	dprint(3, ("sending sig %d to %d\n", event, so->so_pgrp));
432 
433 	if (so->so_pgrp > 0) {
434 		/*
435 		 * XXX This unfortunately still generates
436 		 * a signal when a fd is closed but
437 		 * the proc is active.
438 		 */
439 		mutex_enter(&pidlock);
440 		proc = prfind(so->so_pgrp);
441 		if (proc == NULL) {
442 			mutex_exit(&pidlock);
443 			return;
444 		}
445 		mutex_enter(&proc->p_lock);
446 		mutex_exit(&pidlock);
447 		socket_sigproc(proc, event);
448 		mutex_exit(&proc->p_lock);
449 	} else {
450 		/*
451 		 * Send to process group. Hold pidlock across
452 		 * calls to socket_sigproc().
453 		 */
454 		pid_t pgrp = -so->so_pgrp;
455 
456 		mutex_enter(&pidlock);
457 		proc = pgfind(pgrp);
458 		while (proc != NULL) {
459 			mutex_enter(&proc->p_lock);
460 			socket_sigproc(proc, event);
461 			mutex_exit(&proc->p_lock);
462 			proc = proc->p_pglink;
463 		}
464 		mutex_exit(&pidlock);
465 	}
466 }
467 
468 #define	MIN(a, b) ((a) < (b) ? (a) : (b))
469 /* Copy userdata into a new mblk_t */
470 mblk_t *
471 socopyinuio(uio_t *uiop, ssize_t iosize, size_t wroff, ssize_t maxblk,
472     size_t tail_len, int *errorp, cred_t *cr)
473 {
474 	mblk_t	*head = NULL, **tail = &head;
475 
476 	ASSERT(iosize == INFPSZ || iosize > 0);
477 
478 	if (iosize == INFPSZ || iosize > uiop->uio_resid)
479 		iosize = uiop->uio_resid;
480 
481 	if (maxblk == INFPSZ)
482 		maxblk = iosize;
483 
484 	/* Nothing to do in these cases, so we're done */
485 	if (iosize < 0 || maxblk < 0 || (maxblk == 0 && iosize > 0))
486 		goto done;
487 
488 	/*
489 	 * We will enter the loop below if iosize is 0; it will allocate an
490 	 * empty message block and call uiomove(9F) which will just return.
491 	 * We could avoid that with an extra check but would only slow
492 	 * down the much more likely case where iosize is larger than 0.
493 	 */
494 	do {
495 		ssize_t blocksize;
496 		mblk_t	*mp;
497 
498 		blocksize = MIN(iosize, maxblk);
499 		ASSERT(blocksize >= 0);
500 		if (is_system_labeled())
501 			mp = allocb_cred(wroff + blocksize + tail_len,
502 			    cr, curproc->p_pid);
503 		else
504 			mp = allocb(wroff + blocksize + tail_len, BPRI_MED);
505 		if (mp == NULL) {
506 			*errorp = ENOMEM;
507 			return (head);
508 		}
509 		mp->b_rptr += wroff;
510 		mp->b_wptr = mp->b_rptr + blocksize;
511 
512 		*tail = mp;
513 		tail = &mp->b_cont;
514 
515 		/* uiomove(9F) either returns 0 or EFAULT */
516 		if ((*errorp = uiomove(mp->b_rptr, (size_t)blocksize,
517 		    UIO_WRITE, uiop)) != 0) {
518 			ASSERT(*errorp != ENOMEM);
519 			freemsg(head);
520 			return (NULL);
521 		}
522 
523 		iosize -= blocksize;
524 	} while (iosize > 0);
525 
526 done:
527 	*errorp = 0;
528 	return (head);
529 }
530 
531 mblk_t *
532 socopyoutuio(mblk_t *mp, struct uio *uiop, ssize_t max_read, int *errorp)
533 {
534 	int error;
535 	ptrdiff_t n;
536 	mblk_t *nmp;
537 
538 	ASSERT(mp->b_wptr >= mp->b_rptr);
539 
540 	/*
541 	 * max_read is the offset of the oobmark and read can not go pass
542 	 * the oobmark.
543 	 */
544 	if (max_read == INFPSZ || max_read > uiop->uio_resid)
545 		max_read = uiop->uio_resid;
546 
547 	do {
548 		if ((n = MIN(max_read, MBLKL(mp))) != 0) {
549 			ASSERT(n > 0);
550 
551 			error = uiomove(mp->b_rptr, n, UIO_READ, uiop);
552 			if (error != 0) {
553 				freemsg(mp);
554 				*errorp = error;
555 				return (NULL);
556 			}
557 		}
558 
559 		mp->b_rptr += n;
560 		max_read -= n;
561 		while (mp != NULL && (mp->b_rptr >= mp->b_wptr)) {
562 			/*
563 			 * get rid of zero length mblks
564 			 */
565 			nmp = mp;
566 			mp = mp->b_cont;
567 			freeb(nmp);
568 		}
569 	} while (mp != NULL && max_read > 0);
570 
571 	*errorp = 0;
572 	return (mp);
573 }
574 
575 static void
576 so_prepend_msg(struct sonode *so, mblk_t *mp, mblk_t *last_tail)
577 {
578 	ASSERT(last_tail != NULL);
579 	mp->b_next = so->so_rcv_q_head;
580 	mp->b_prev = last_tail;
581 	ASSERT(!(DB_FLAGS(mp) & DBLK_UIOA));
582 
583 	if (so->so_rcv_q_head == NULL) {
584 		ASSERT(so->so_rcv_q_last_head == NULL);
585 		so->so_rcv_q_last_head = mp;
586 #ifdef DEBUG
587 	} else {
588 		ASSERT(!(DB_FLAGS(so->so_rcv_q_head) & DBLK_UIOA));
589 #endif
590 	}
591 	so->so_rcv_q_head = mp;
592 
593 #ifdef DEBUG
594 	if (so_debug_length) {
595 		mutex_enter(&so->so_lock);
596 		ASSERT(so_check_length(so));
597 		mutex_exit(&so->so_lock);
598 	}
599 #endif
600 }
601 
602 /*
603  * Move a mblk chain (mp_head, mp_last_head) to the sonode's rcv queue so it
604  * can be processed by so_dequeue_msg().
605  */
606 void
607 so_process_new_message(struct sonode *so, mblk_t *mp_head, mblk_t *mp_last_head)
608 {
609 	ASSERT(mp_head->b_prev != NULL);
610 	if (so->so_rcv_q_head  == NULL) {
611 		so->so_rcv_q_head = mp_head;
612 		so->so_rcv_q_last_head = mp_last_head;
613 		ASSERT(so->so_rcv_q_last_head->b_prev != NULL);
614 	} else {
615 		boolean_t flag_equal = ((DB_FLAGS(mp_head) & DBLK_UIOA) ==
616 		    (DB_FLAGS(so->so_rcv_q_last_head) & DBLK_UIOA));
617 
618 		if (mp_head->b_next == NULL &&
619 		    DB_TYPE(mp_head) == M_DATA &&
620 		    DB_TYPE(so->so_rcv_q_last_head) == M_DATA && flag_equal) {
621 			so->so_rcv_q_last_head->b_prev->b_cont = mp_head;
622 			so->so_rcv_q_last_head->b_prev = mp_head->b_prev;
623 			mp_head->b_prev = NULL;
624 		} else if (flag_equal && (DB_FLAGS(mp_head) & DBLK_UIOA)) {
625 			/*
626 			 * Append to last_head if more than one mblks, and both
627 			 * mp_head and last_head are I/OAT mblks.
628 			 */
629 			ASSERT(mp_head->b_next != NULL);
630 			so->so_rcv_q_last_head->b_prev->b_cont = mp_head;
631 			so->so_rcv_q_last_head->b_prev = mp_head->b_prev;
632 			mp_head->b_prev = NULL;
633 
634 			so->so_rcv_q_last_head->b_next = mp_head->b_next;
635 			mp_head->b_next = NULL;
636 			so->so_rcv_q_last_head = mp_last_head;
637 		} else {
638 #ifdef DEBUG
639 			{
640 				mblk_t *tmp_mblk;
641 				tmp_mblk = mp_head;
642 				while (tmp_mblk != NULL) {
643 					ASSERT(tmp_mblk->b_prev != NULL);
644 					tmp_mblk = tmp_mblk->b_next;
645 				}
646 			}
647 #endif
648 			so->so_rcv_q_last_head->b_next = mp_head;
649 			so->so_rcv_q_last_head = mp_last_head;
650 		}
651 	}
652 }
653 
654 int
655 so_dequeue_msg(struct sonode *so, mblk_t **mctlp, struct uio *uiop,
656     rval_t *rvalp, int flags)
657 {
658 	mblk_t	*mp, *nmp;
659 	mblk_t	*savemp, *savemptail;
660 	mblk_t	*new_msg_head;
661 	mblk_t	*new_msg_last_head;
662 	mblk_t	*last_tail;
663 	boolean_t partial_read;
664 	boolean_t reset_atmark = B_FALSE;
665 	int more = 0;
666 	int error;
667 	ssize_t oobmark;
668 	sodirect_t *sodp = so->so_direct;
669 
670 	partial_read = B_FALSE;
671 	*mctlp = NULL;
672 again:
673 	mutex_enter(&so->so_lock);
674 again1:
675 #ifdef DEBUG
676 	if (so_debug_length) {
677 		ASSERT(so_check_length(so));
678 	}
679 #endif
680 	/*
681 	 * First move messages from the dump area to processing area
682 	 */
683 	if (sodp != NULL) {
684 		if (sodp->sod_enabled) {
685 			if (sodp->sod_uioa.uioa_state & UIOA_ALLOC) {
686 				/* nothing to uioamove */
687 				sodp = NULL;
688 			} else if (sodp->sod_uioa.uioa_state & UIOA_INIT) {
689 				sodp->sod_uioa.uioa_state &= UIOA_CLR;
690 				sodp->sod_uioa.uioa_state |= UIOA_ENABLED;
691 				/*
692 				 * try to uioamove() the data that
693 				 * has already queued.
694 				 */
695 				sod_uioa_so_init(so, sodp, uiop);
696 			}
697 		} else {
698 			sodp = NULL;
699 		}
700 	}
701 	new_msg_head = so->so_rcv_head;
702 	new_msg_last_head = so->so_rcv_last_head;
703 	so->so_rcv_head = NULL;
704 	so->so_rcv_last_head = NULL;
705 	oobmark = so->so_oobmark;
706 	/*
707 	 * We can release the lock as there can only be one reader
708 	 */
709 	mutex_exit(&so->so_lock);
710 
711 	if (so->so_state & SS_RCVATMARK) {
712 		reset_atmark = B_TRUE;
713 	}
714 	if (new_msg_head != NULL) {
715 		so_process_new_message(so, new_msg_head, new_msg_last_head);
716 	}
717 	savemp = savemptail = NULL;
718 	rvalp->r_val1 = 0;
719 	error = 0;
720 	mp = so->so_rcv_q_head;
721 
722 	if (mp != NULL &&
723 	    (so->so_rcv_timer_tid == 0 ||
724 	    so->so_rcv_queued >= so->so_rcv_thresh)) {
725 		partial_read = B_FALSE;
726 
727 		if (flags & MSG_PEEK) {
728 			if ((nmp = dupmsg(mp)) == NULL &&
729 			    (nmp = copymsg(mp)) == NULL) {
730 				size_t size = msgsize(mp);
731 
732 				error = strwaitbuf(size, BPRI_HI);
733 				if (error) {
734 					return (error);
735 				}
736 				goto again;
737 			}
738 			mp = nmp;
739 		} else {
740 			ASSERT(mp->b_prev != NULL);
741 			last_tail = mp->b_prev;
742 			mp->b_prev = NULL;
743 			so->so_rcv_q_head = mp->b_next;
744 			if (so->so_rcv_q_head == NULL) {
745 				so->so_rcv_q_last_head = NULL;
746 			}
747 			mp->b_next = NULL;
748 		}
749 
750 		ASSERT(mctlp != NULL);
751 		/*
752 		 * First process PROTO or PCPROTO blocks, if any.
753 		 */
754 		if (DB_TYPE(mp) != M_DATA) {
755 			*mctlp = mp;
756 			savemp = mp;
757 			savemptail = mp;
758 			ASSERT(DB_TYPE(mp) == M_PROTO ||
759 			    DB_TYPE(mp) == M_PCPROTO);
760 			while (mp->b_cont != NULL &&
761 			    DB_TYPE(mp->b_cont) != M_DATA) {
762 				ASSERT(DB_TYPE(mp->b_cont) == M_PROTO ||
763 				    DB_TYPE(mp->b_cont) == M_PCPROTO);
764 				mp = mp->b_cont;
765 				savemptail = mp;
766 			}
767 			mp = savemptail->b_cont;
768 			savemptail->b_cont = NULL;
769 		}
770 
771 		ASSERT(DB_TYPE(mp) == M_DATA);
772 		/*
773 		 * Now process DATA blocks, if any. Note that for sodirect
774 		 * enabled socket, uio_resid can be 0.
775 		 */
776 		if (uiop->uio_resid >= 0) {
777 			ssize_t copied = 0;
778 
779 			if (sodp != NULL && (DB_FLAGS(mp) & DBLK_UIOA)) {
780 				mutex_enter(&so->so_lock);
781 				ASSERT(uiop == (uio_t *)&sodp->sod_uioa);
782 				copied = sod_uioa_mblk(so, mp);
783 				if (copied > 0)
784 					partial_read = B_TRUE;
785 				mutex_exit(&so->so_lock);
786 				/* mark this mblk as processed */
787 				mp = NULL;
788 			} else {
789 				ssize_t oldresid = uiop->uio_resid;
790 
791 				if (MBLKL(mp) < so_mblk_pull_len) {
792 					if (pullupmsg(mp, -1) == 1) {
793 						last_tail = mp;
794 					}
795 				}
796 				/*
797 				 * Can not read beyond the oobmark
798 				 */
799 				mp = socopyoutuio(mp, uiop,
800 				    oobmark == 0 ? INFPSZ : oobmark, &error);
801 				if (error != 0) {
802 					freemsg(*mctlp);
803 					*mctlp = NULL;
804 					more = 0;
805 					goto done;
806 				}
807 				ASSERT(oldresid >= uiop->uio_resid);
808 				copied = oldresid - uiop->uio_resid;
809 				if (oldresid > uiop->uio_resid)
810 					partial_read = B_TRUE;
811 			}
812 			ASSERT(copied >= 0);
813 			if (copied > 0 && !(flags & MSG_PEEK)) {
814 				mutex_enter(&so->so_lock);
815 				so->so_rcv_queued -= copied;
816 				ASSERT(so->so_oobmark >= 0);
817 				if (so->so_oobmark > 0) {
818 					so->so_oobmark -= copied;
819 					ASSERT(so->so_oobmark >= 0);
820 					if (so->so_oobmark == 0) {
821 						ASSERT(so->so_state &
822 						    SS_OOBPEND);
823 						so->so_oobmark = 0;
824 						so->so_state |= SS_RCVATMARK;
825 					}
826 				}
827 				if (so->so_flowctrld && so->so_rcv_queued <
828 				    so->so_rcvlowat) {
829 					so->so_flowctrld = B_FALSE;
830 					mutex_exit(&so->so_lock);
831 					/*
832 					 * Open up flow control. SCTP does
833 					 * not have any downcalls, and it will
834 					 * clr flow ctrl in sosctp_recvmsg().
835 					 */
836 					if (so->so_downcalls != NULL &&
837 					    so->so_downcalls->sd_clr_flowctrl !=
838 					    NULL) {
839 						(*so->so_downcalls->
840 						    sd_clr_flowctrl)
841 						    (so->so_proto_handle);
842 					}
843 				} else {
844 					mutex_exit(&so->so_lock);
845 				}
846 			}
847 		}
848 		if (mp != NULL) { /* more data blocks in msg */
849 			more |= MOREDATA;
850 			if ((flags & (MSG_PEEK|MSG_TRUNC))) {
851 				if (flags & MSG_TRUNC &&
852 				    ((flags & MSG_PEEK) == 0)) {
853 					mutex_enter(&so->so_lock);
854 					so->so_rcv_queued -= msgdsize(mp);
855 					mutex_exit(&so->so_lock);
856 				}
857 				freemsg(mp);
858 			} else if (partial_read && !somsghasdata(mp)) {
859 				/*
860 				 * Avoid queuing a zero-length tail part of
861 				 * a message. partial_read == 1 indicates that
862 				 * we read some of the message.
863 				 */
864 				freemsg(mp);
865 				more &= ~MOREDATA;
866 			} else {
867 				if (savemp != NULL &&
868 				    (flags & MSG_DUPCTRL)) {
869 					mblk_t *nmp;
870 					/*
871 					 * There should only be non data mblks
872 					 */
873 					ASSERT(DB_TYPE(savemp) != M_DATA &&
874 					    DB_TYPE(savemptail) != M_DATA);
875 try_again:
876 					if ((nmp = dupmsg(savemp)) == NULL &&
877 					    (nmp = copymsg(savemp)) == NULL) {
878 
879 						size_t size = msgsize(savemp);
880 
881 						error = strwaitbuf(size,
882 						    BPRI_HI);
883 						if (error != 0) {
884 							/*
885 							 * In case we
886 							 * cannot copy
887 							 * control data
888 							 * free the remaining
889 							 * data.
890 							 */
891 							freemsg(mp);
892 							goto done;
893 						}
894 						goto try_again;
895 					}
896 
897 					ASSERT(nmp != NULL);
898 					ASSERT(DB_TYPE(nmp) != M_DATA);
899 					savemptail->b_cont = mp;
900 					*mctlp = nmp;
901 					mp = savemp;
902 				}
903 				/*
904 				 * putback mp
905 				 */
906 				so_prepend_msg(so, mp, last_tail);
907 			}
908 		}
909 
910 		/* fast check so_rcv_head if there is more data */
911 		if (partial_read && !(so->so_state & SS_RCVATMARK) &&
912 		    *mctlp == NULL && uiop->uio_resid > 0 &&
913 		    !(flags & MSG_PEEK) && so->so_rcv_head != NULL) {
914 			goto again;
915 		}
916 	} else if (!partial_read) {
917 		mutex_enter(&so->so_lock);
918 		if (so->so_error != 0) {
919 			error = sogeterr(so, !(flags & MSG_PEEK));
920 			mutex_exit(&so->so_lock);
921 			return (error);
922 		}
923 		/*
924 		 * No pending data. Return right away for nonblocking
925 		 * socket, otherwise sleep waiting for data.
926 		 */
927 		if (!(so->so_state & SS_CANTRCVMORE) && uiop->uio_resid > 0) {
928 			if ((uiop->uio_fmode & (FNDELAY|FNONBLOCK)) ||
929 			    (flags & MSG_DONTWAIT)) {
930 				error = EWOULDBLOCK;
931 			} else {
932 				if (so->so_state & (SS_CLOSING |
933 				    SS_FALLBACK_PENDING)) {
934 					mutex_exit(&so->so_lock);
935 					error = EINTR;
936 					goto done;
937 				}
938 
939 				if (so->so_rcv_head != NULL) {
940 					goto again1;
941 				}
942 				so->so_rcv_wakeup = B_TRUE;
943 				so->so_rcv_wanted = uiop->uio_resid;
944 				if (so->so_rcvtimeo == 0) {
945 					/*
946 					 * Zero means disable timeout.
947 					 */
948 					error = cv_wait_sig(&so->so_rcv_cv,
949 					    &so->so_lock);
950 				} else {
951 					clock_t now;
952 					time_to_wait(&now, so->so_rcvtimeo);
953 					error = cv_timedwait_sig(&so->so_rcv_cv,
954 					    &so->so_lock, now);
955 				}
956 				so->so_rcv_wakeup = B_FALSE;
957 				so->so_rcv_wanted = 0;
958 
959 				if (error == 0) {
960 					error = EINTR;
961 				} else if (error == -1) {
962 					error = EAGAIN;
963 				} else {
964 					goto again1;
965 				}
966 			}
967 		}
968 		mutex_exit(&so->so_lock);
969 	}
970 	if (reset_atmark && partial_read && !(flags & MSG_PEEK)) {
971 		/*
972 		 * We are passed the mark, update state
973 		 * 4.3BSD and 4.4BSD clears the mark when peeking across it.
974 		 * The draft Posix socket spec states that the mark should
975 		 * not be cleared when peeking. We follow the latter.
976 		 */
977 		mutex_enter(&so->so_lock);
978 		ASSERT(so_verify_oobstate(so));
979 		so->so_state &= ~(SS_OOBPEND|SS_HAVEOOBDATA|SS_RCVATMARK);
980 		freemsg(so->so_oobmsg);
981 		so->so_oobmsg = NULL;
982 		ASSERT(so_verify_oobstate(so));
983 		mutex_exit(&so->so_lock);
984 	}
985 	ASSERT(so->so_rcv_wakeup == B_FALSE);
986 done:
987 	if (sodp != NULL) {
988 		mutex_enter(&so->so_lock);
989 		if (sodp->sod_enabled &&
990 		    (sodp->sod_uioa.uioa_state & UIOA_ENABLED)) {
991 			SOD_UIOAFINI(sodp);
992 			if (sodp->sod_uioa.uioa_mbytes > 0) {
993 				ASSERT(so->so_rcv_q_head != NULL ||
994 				    so->so_rcv_head != NULL);
995 				so->so_rcv_queued -= sod_uioa_mblk(so, NULL);
996 				if (error == EWOULDBLOCK)
997 					error = 0;
998 			}
999 		}
1000 		mutex_exit(&so->so_lock);
1001 	}
1002 #ifdef DEBUG
1003 	if (so_debug_length) {
1004 		mutex_enter(&so->so_lock);
1005 		ASSERT(so_check_length(so));
1006 		mutex_exit(&so->so_lock);
1007 	}
1008 #endif
1009 	rvalp->r_val1 = more;
1010 	return (error);
1011 }
1012 
1013 /*
1014  * Enqueue data from the protocol on the socket's rcv queue.
1015  *
1016  * We try to hook new M_DATA mblks onto an existing chain, however,
1017  * that cannot be done if the existing chain has already been
1018  * processed by I/OAT. Non-M_DATA mblks are just linked together via
1019  * b_next. In all cases the b_prev of the enqueued mblk is set to
1020  * point to the last mblk in its b_cont chain.
1021  */
1022 void
1023 so_enqueue_msg(struct sonode *so, mblk_t *mp, size_t msg_size)
1024 {
1025 	ASSERT(MUTEX_HELD(&so->so_lock));
1026 
1027 #ifdef DEBUG
1028 	if (so_debug_length) {
1029 		ASSERT(so_check_length(so));
1030 	}
1031 #endif
1032 	so->so_rcv_queued += msg_size;
1033 
1034 	if (so->so_rcv_head == NULL) {
1035 		ASSERT(so->so_rcv_last_head == NULL);
1036 		so->so_rcv_head = mp;
1037 		so->so_rcv_last_head = mp;
1038 	} else if ((DB_TYPE(mp) == M_DATA &&
1039 	    DB_TYPE(so->so_rcv_last_head) == M_DATA) &&
1040 	    ((DB_FLAGS(mp) & DBLK_UIOA) ==
1041 	    (DB_FLAGS(so->so_rcv_last_head) & DBLK_UIOA))) {
1042 		/* Added to the end */
1043 		ASSERT(so->so_rcv_last_head != NULL);
1044 		ASSERT(so->so_rcv_last_head->b_prev != NULL);
1045 		so->so_rcv_last_head->b_prev->b_cont = mp;
1046 	} else {
1047 		/* Start a new end */
1048 		so->so_rcv_last_head->b_next = mp;
1049 		so->so_rcv_last_head = mp;
1050 	}
1051 	while (mp->b_cont != NULL)
1052 		mp = mp->b_cont;
1053 
1054 	so->so_rcv_last_head->b_prev = mp;
1055 #ifdef DEBUG
1056 	if (so_debug_length) {
1057 		ASSERT(so_check_length(so));
1058 	}
1059 #endif
1060 }
1061 
1062 /*
1063  * Return B_TRUE if there is data in the message, B_FALSE otherwise.
1064  */
1065 boolean_t
1066 somsghasdata(mblk_t *mp)
1067 {
1068 	for (; mp; mp = mp->b_cont)
1069 		if (mp->b_datap->db_type == M_DATA) {
1070 			ASSERT(mp->b_wptr >= mp->b_rptr);
1071 			if (mp->b_wptr > mp->b_rptr)
1072 				return (B_TRUE);
1073 		}
1074 	return (B_FALSE);
1075 }
1076 
1077 /*
1078  * Flush the read side of sockfs.
1079  *
1080  * The caller must be sure that a reader is not already active when the
1081  * buffer is being flushed.
1082  */
1083 void
1084 so_rcv_flush(struct sonode *so)
1085 {
1086 	mblk_t  *mp;
1087 
1088 	ASSERT(MUTEX_HELD(&so->so_lock));
1089 
1090 	if (so->so_oobmsg != NULL) {
1091 		freemsg(so->so_oobmsg);
1092 		so->so_oobmsg = NULL;
1093 		so->so_oobmark = 0;
1094 		so->so_state &=
1095 		    ~(SS_OOBPEND|SS_HAVEOOBDATA|SS_HADOOBDATA|SS_RCVATMARK);
1096 	}
1097 
1098 	/*
1099 	 * Free messages sitting in the send and recv queue
1100 	 */
1101 	while (so->so_rcv_q_head != NULL) {
1102 		mp = so->so_rcv_q_head;
1103 		so->so_rcv_q_head = mp->b_next;
1104 		mp->b_next = mp->b_prev = NULL;
1105 		freemsg(mp);
1106 	}
1107 	while (so->so_rcv_head != NULL) {
1108 		mp = so->so_rcv_head;
1109 		so->so_rcv_head = mp->b_next;
1110 		mp->b_next = mp->b_prev = NULL;
1111 		freemsg(mp);
1112 	}
1113 	so->so_rcv_queued = 0;
1114 	so->so_rcv_q_head = NULL;
1115 	so->so_rcv_q_last_head = NULL;
1116 	so->so_rcv_head = NULL;
1117 	so->so_rcv_last_head = NULL;
1118 }
1119 
1120 /*
1121  * Handle recv* calls that set MSG_OOB or MSG_OOB together with MSG_PEEK.
1122  */
1123 int
1124 sorecvoob(struct sonode *so, struct nmsghdr *msg, struct uio *uiop, int flags,
1125     boolean_t oob_inline)
1126 {
1127 	mblk_t		*mp, *nmp;
1128 	int		error;
1129 
1130 	dprintso(so, 1, ("sorecvoob(%p, %p, 0x%x)\n", (void *)so, (void *)msg,
1131 	    flags));
1132 
1133 	if (msg != NULL) {
1134 		/*
1135 		 * There is never any oob data with addresses or control since
1136 		 * the T_EXDATA_IND does not carry any options.
1137 		 */
1138 		msg->msg_controllen = 0;
1139 		msg->msg_namelen = 0;
1140 		msg->msg_flags = 0;
1141 	}
1142 
1143 	mutex_enter(&so->so_lock);
1144 	ASSERT(so_verify_oobstate(so));
1145 	if (oob_inline ||
1146 	    (so->so_state & (SS_OOBPEND|SS_HADOOBDATA)) != SS_OOBPEND) {
1147 		dprintso(so, 1, ("sorecvoob: inline or data consumed\n"));
1148 		mutex_exit(&so->so_lock);
1149 		return (EINVAL);
1150 	}
1151 	if (!(so->so_state & SS_HAVEOOBDATA)) {
1152 		dprintso(so, 1, ("sorecvoob: no data yet\n"));
1153 		mutex_exit(&so->so_lock);
1154 		return (EWOULDBLOCK);
1155 	}
1156 	ASSERT(so->so_oobmsg != NULL);
1157 	mp = so->so_oobmsg;
1158 	if (flags & MSG_PEEK) {
1159 		/*
1160 		 * Since recv* can not return ENOBUFS we can not use dupmsg.
1161 		 * Instead we revert to the consolidation private
1162 		 * allocb_wait plus bcopy.
1163 		 */
1164 		mblk_t *mp1;
1165 
1166 		mp1 = allocb_wait(msgdsize(mp), BPRI_MED, STR_NOSIG, NULL);
1167 		ASSERT(mp1);
1168 
1169 		while (mp != NULL) {
1170 			ssize_t size;
1171 
1172 			size = MBLKL(mp);
1173 			bcopy(mp->b_rptr, mp1->b_wptr, size);
1174 			mp1->b_wptr += size;
1175 			ASSERT(mp1->b_wptr <= mp1->b_datap->db_lim);
1176 			mp = mp->b_cont;
1177 		}
1178 		mp = mp1;
1179 	} else {
1180 		/*
1181 		 * Update the state indicating that the data has been consumed.
1182 		 * Keep SS_OOBPEND set until data is consumed past the mark.
1183 		 */
1184 		so->so_oobmsg = NULL;
1185 		so->so_state ^= SS_HAVEOOBDATA|SS_HADOOBDATA;
1186 	}
1187 	ASSERT(so_verify_oobstate(so));
1188 	mutex_exit(&so->so_lock);
1189 
1190 	error = 0;
1191 	nmp = mp;
1192 	while (nmp != NULL && uiop->uio_resid > 0) {
1193 		ssize_t n = MBLKL(nmp);
1194 
1195 		n = MIN(n, uiop->uio_resid);
1196 		if (n > 0)
1197 			error = uiomove(nmp->b_rptr, n,
1198 			    UIO_READ, uiop);
1199 		if (error)
1200 			break;
1201 		nmp = nmp->b_cont;
1202 	}
1203 	ASSERT(mp->b_next == NULL && mp->b_prev == NULL);
1204 	freemsg(mp);
1205 	return (error);
1206 }
1207 
1208 /*
1209  * Allocate and initializ sonode
1210  */
1211 /* ARGSUSED */
1212 struct sonode *
1213 socket_sonode_create(struct sockparams *sp, int family, int type,
1214     int protocol, int version, int sflags, int *errorp, struct cred *cr)
1215 {
1216 	sonode_t *so;
1217 	int	kmflags;
1218 
1219 	/*
1220 	 * Choose the right set of sonodeops based on the upcall and
1221 	 * down call version that the protocol has provided
1222 	 */
1223 	if (SOCK_UC_VERSION != sp->sp_smod_info->smod_uc_version ||
1224 	    SOCK_DC_VERSION != sp->sp_smod_info->smod_dc_version) {
1225 		/*
1226 		 * mismatch
1227 		 */
1228 #ifdef DEBUG
1229 		cmn_err(CE_CONT, "protocol and socket module version mismatch");
1230 #endif
1231 		*errorp = EINVAL;
1232 		return (NULL);
1233 	}
1234 
1235 	kmflags = (sflags & SOCKET_NOSLEEP) ? KM_NOSLEEP : KM_SLEEP;
1236 
1237 	so = kmem_cache_alloc(socket_cache, kmflags);
1238 	if (so == NULL) {
1239 		*errorp = ENOMEM;
1240 		return (NULL);
1241 	}
1242 
1243 	sonode_init(so, sp, family, type, protocol, &so_sonodeops);
1244 
1245 	if (version == SOV_DEFAULT)
1246 		version = so_default_version;
1247 
1248 	so->so_version = (short)version;
1249 
1250 	/*
1251 	 * set the default values to be INFPSZ
1252 	 * if a protocol desires it can change the value later
1253 	 */
1254 	so->so_proto_props.sopp_rxhiwat = SOCKET_RECVHIWATER;
1255 	so->so_proto_props.sopp_rxlowat = SOCKET_RECVLOWATER;
1256 	so->so_proto_props.sopp_maxpsz = INFPSZ;
1257 	so->so_proto_props.sopp_maxblk = INFPSZ;
1258 
1259 	return (so);
1260 }
1261 
1262 int
1263 socket_init_common(struct sonode *so, struct sonode *pso, int flags, cred_t *cr)
1264 {
1265 	int error = 0;
1266 
1267 	if (pso != NULL) {
1268 		/*
1269 		 * We have a passive open, so inherit basic state from
1270 		 * the parent (listener).
1271 		 *
1272 		 * No need to grab the new sonode's lock, since there is no
1273 		 * one that can have a reference to it.
1274 		 */
1275 		mutex_enter(&pso->so_lock);
1276 
1277 		so->so_state |= SS_ISCONNECTED | (pso->so_state & SS_ASYNC);
1278 		so->so_pgrp = pso->so_pgrp;
1279 		so->so_rcvtimeo = pso->so_rcvtimeo;
1280 		so->so_sndtimeo = pso->so_sndtimeo;
1281 		so->so_xpg_rcvbuf = pso->so_xpg_rcvbuf;
1282 		/*
1283 		 * Make note of the socket level options. TCP and IP level
1284 		 * options are already inherited. We could do all this after
1285 		 * accept is successful but doing it here simplifies code and
1286 		 * no harm done for error case.
1287 		 */
1288 		so->so_options = pso->so_options & (SO_DEBUG|SO_REUSEADDR|
1289 		    SO_KEEPALIVE|SO_DONTROUTE|SO_BROADCAST|SO_USELOOPBACK|
1290 		    SO_OOBINLINE|SO_DGRAM_ERRIND|SO_LINGER);
1291 		so->so_proto_props = pso->so_proto_props;
1292 		so->so_mode = pso->so_mode;
1293 		so->so_pollev = pso->so_pollev & SO_POLLEV_ALWAYS;
1294 
1295 		mutex_exit(&pso->so_lock);
1296 	} else {
1297 		struct sockparams *sp = so->so_sockparams;
1298 		sock_upcalls_t *upcalls_to_use;
1299 
1300 		/*
1301 		 * Based on the version number select the right upcalls to
1302 		 * pass down. Currently we only have one version so choose
1303 		 * default
1304 		 */
1305 		upcalls_to_use = &so_upcalls;
1306 
1307 		/* active open, so create a lower handle */
1308 		so->so_proto_handle =
1309 		    sp->sp_smod_info->smod_proto_create_func(so->so_family,
1310 		    so->so_type, so->so_protocol, &so->so_downcalls,
1311 		    &so->so_mode, &error, flags, cr);
1312 
1313 		if (so->so_proto_handle == NULL) {
1314 			ASSERT(error != 0);
1315 			/*
1316 			 * To be safe; if a lower handle cannot be created, and
1317 			 * the proto does not give a reason why, assume there
1318 			 * was a lack of memory.
1319 			 */
1320 			return ((error == 0) ? ENOMEM : error);
1321 		}
1322 		ASSERT(so->so_downcalls != NULL);
1323 		ASSERT(so->so_downcalls->sd_send != NULL ||
1324 		    so->so_downcalls->sd_send_uio != NULL);
1325 		if (so->so_downcalls->sd_recv_uio != NULL) {
1326 			ASSERT(so->so_downcalls->sd_poll != NULL);
1327 			so->so_pollev |= SO_POLLEV_ALWAYS;
1328 		}
1329 
1330 		(*so->so_downcalls->sd_activate)(so->so_proto_handle,
1331 		    (sock_upper_handle_t)so, upcalls_to_use, 0, cr);
1332 
1333 		/* Wildcard */
1334 
1335 		/*
1336 		 * FIXME No need for this, the protocol can deal with it in
1337 		 * sd_create(). Should update ICMP.
1338 		 */
1339 		if (so->so_protocol != so->so_sockparams->sp_protocol) {
1340 			int protocol = so->so_protocol;
1341 			int error;
1342 			/*
1343 			 * Issue SO_PROTOTYPE setsockopt.
1344 			 */
1345 			error = socket_setsockopt(so, SOL_SOCKET, SO_PROTOTYPE,
1346 			    &protocol, (t_uscalar_t)sizeof (protocol), cr);
1347 			if (error) {
1348 				(void) (*so->so_downcalls->sd_close)
1349 				    (so->so_proto_handle, 0, cr);
1350 
1351 				mutex_enter(&so->so_lock);
1352 				so_rcv_flush(so);
1353 				mutex_exit(&so->so_lock);
1354 				/*
1355 				 * Setsockopt often fails with ENOPROTOOPT but
1356 				 * socket() should fail with
1357 				 * EPROTONOSUPPORT/EPROTOTYPE.
1358 				 */
1359 				return (EPROTONOSUPPORT);
1360 			}
1361 		}
1362 	}
1363 
1364 	if (uioasync.enabled)
1365 		sod_sock_init(so);
1366 
1367 	return (0);
1368 }
1369 
1370 /*
1371  * int socket_ioctl_common(struct sonode *so, int cmd, intptr_t arg, int mode,
1372  *         struct cred *cr, int32_t *rvalp)
1373  *
1374  * Handle ioctls that manipulate basic socket state; non-blocking,
1375  * async, etc.
1376  *
1377  * Returns:
1378  *   < 0  - ioctl was not handle
1379  *  >= 0  - ioctl was handled, if > 0, then it is an errno
1380  *
1381  * Notes:
1382  *   Assumes the standard receive buffer is used to obtain info for
1383  *   NREAD.
1384  */
1385 /* ARGSUSED */
1386 int
1387 socket_ioctl_common(struct sonode *so, int cmd, intptr_t arg, int mode,
1388     struct cred *cr, int32_t *rvalp)
1389 {
1390 	switch (cmd) {
1391 	case SIOCSQPTR:
1392 		/*
1393 		 * SIOCSQPTR is valid only when helper stream is created
1394 		 * by the protocol.
1395 		 */
1396 
1397 		return (EOPNOTSUPP);
1398 	case FIONBIO: {
1399 		int32_t value;
1400 
1401 		if (so_copyin((void *)arg, &value, sizeof (int32_t),
1402 		    (mode & (int)FKIOCTL)))
1403 			return (EFAULT);
1404 
1405 		mutex_enter(&so->so_lock);
1406 		if (value) {
1407 			so->so_state |= SS_NDELAY;
1408 		} else {
1409 			so->so_state &= ~SS_NDELAY;
1410 		}
1411 		mutex_exit(&so->so_lock);
1412 		return (0);
1413 	}
1414 	case FIOASYNC: {
1415 		int32_t value;
1416 
1417 		if (so_copyin((void *)arg, &value, sizeof (int32_t),
1418 		    (mode & (int)FKIOCTL)))
1419 			return (EFAULT);
1420 
1421 		mutex_enter(&so->so_lock);
1422 
1423 		if (value) {
1424 			/* Turn on SIGIO */
1425 			so->so_state |= SS_ASYNC;
1426 		} else {
1427 			/* Turn off SIGIO */
1428 			so->so_state &= ~SS_ASYNC;
1429 		}
1430 		mutex_exit(&so->so_lock);
1431 
1432 		return (0);
1433 	}
1434 
1435 	case SIOCSPGRP:
1436 	case FIOSETOWN: {
1437 		int error;
1438 		pid_t pid;
1439 
1440 		if (so_copyin((void *)arg, &pid, sizeof (pid_t),
1441 		    (mode & (int)FKIOCTL)))
1442 			return (EFAULT);
1443 
1444 		mutex_enter(&so->so_lock);
1445 		error = (pid != so->so_pgrp) ? socket_chgpgrp(so, pid) : 0;
1446 		mutex_exit(&so->so_lock);
1447 		return (error);
1448 	}
1449 	case SIOCGPGRP:
1450 	case FIOGETOWN:
1451 		if (so_copyout(&so->so_pgrp, (void *)arg,
1452 		    sizeof (pid_t), (mode & (int)FKIOCTL)))
1453 			return (EFAULT);
1454 
1455 		return (0);
1456 	case SIOCATMARK: {
1457 		int retval;
1458 
1459 		/*
1460 		 * Only protocols that support urgent data can handle ATMARK.
1461 		 */
1462 		if ((so->so_mode & SM_EXDATA) == 0)
1463 			return (EINVAL);
1464 
1465 		/*
1466 		 * If the protocol is maintaining its own buffer, then the
1467 		 * request must be passed down.
1468 		 */
1469 		if (so->so_downcalls->sd_recv_uio != NULL)
1470 			return (-1);
1471 
1472 		retval = (so->so_state & SS_RCVATMARK) != 0;
1473 
1474 		if (so_copyout(&retval, (void *)arg, sizeof (int),
1475 		    (mode & (int)FKIOCTL))) {
1476 			return (EFAULT);
1477 		}
1478 		return (0);
1479 	}
1480 
1481 	case FIONREAD: {
1482 		int retval;
1483 
1484 		/*
1485 		 * If the protocol is maintaining its own buffer, then the
1486 		 * request must be passed down.
1487 		 */
1488 		if (so->so_downcalls->sd_recv_uio != NULL)
1489 			return (-1);
1490 
1491 		retval = MIN(so->so_rcv_queued, INT_MAX);
1492 
1493 		if (so_copyout(&retval, (void *)arg,
1494 		    sizeof (retval), (mode & (int)FKIOCTL))) {
1495 			return (EFAULT);
1496 		}
1497 		return (0);
1498 	}
1499 
1500 	case _I_GETPEERCRED: {
1501 		int error = 0;
1502 
1503 		if ((mode & FKIOCTL) == 0)
1504 			return (EINVAL);
1505 
1506 		mutex_enter(&so->so_lock);
1507 		if ((so->so_mode & SM_CONNREQUIRED) == 0) {
1508 			error = ENOTSUP;
1509 		} else if ((so->so_state & SS_ISCONNECTED) == 0) {
1510 			error = ENOTCONN;
1511 		} else if (so->so_peercred != NULL) {
1512 			k_peercred_t *kp = (k_peercred_t *)arg;
1513 			kp->pc_cr = so->so_peercred;
1514 			kp->pc_cpid = so->so_cpid;
1515 			crhold(so->so_peercred);
1516 		} else {
1517 			error = EINVAL;
1518 		}
1519 		mutex_exit(&so->so_lock);
1520 		return (error);
1521 	}
1522 	default:
1523 		return (-1);
1524 	}
1525 }
1526 
1527 /*
1528  * Handle the I_NREAD STREAM ioctl.
1529  */
1530 static int
1531 so_strioc_nread(struct sonode *so, intptr_t arg, int mode, int32_t *rvalp)
1532 {
1533 	size_t size = 0;
1534 	int retval;
1535 	int count = 0;
1536 	mblk_t *mp;
1537 
1538 	if (so->so_downcalls == NULL ||
1539 	    so->so_downcalls->sd_recv_uio != NULL)
1540 		return (EINVAL);
1541 
1542 	mutex_enter(&so->so_lock);
1543 	/* Wait for reader to get out of the way. */
1544 	while (so->so_flag & SOREADLOCKED) {
1545 		/*
1546 		 * If reader is waiting for data, then there should be nothing
1547 		 * on the rcv queue.
1548 		 */
1549 		if (so->so_rcv_wakeup)
1550 			goto out;
1551 
1552 		so->so_flag |= SOWANT;
1553 		/* Do a timed sleep, in case the reader goes to sleep. */
1554 		(void) cv_timedwait(&so->so_state_cv, &so->so_lock,
1555 		    lbolt + drv_usectohz(10));
1556 	}
1557 
1558 	/*
1559 	 * Since we are holding so_lock no new reader will come in, and the
1560 	 * protocol will not be able to enqueue data. So it's safe to walk
1561 	 * both rcv queues.
1562 	 */
1563 	mp = so->so_rcv_q_head;
1564 	if (mp != NULL) {
1565 		size = msgdsize(so->so_rcv_q_head);
1566 		for (; mp != NULL; mp = mp->b_next)
1567 			count++;
1568 	} else {
1569 		/*
1570 		 * In case the processing list was empty, get the size of the
1571 		 * next msg in line.
1572 		 */
1573 		size = msgdsize(so->so_rcv_head);
1574 	}
1575 
1576 	for (mp = so->so_rcv_head; mp != NULL; mp = mp->b_next)
1577 		count++;
1578 out:
1579 	mutex_exit(&so->so_lock);
1580 
1581 	/*
1582 	 * Drop down from size_t to the "int" required by the
1583 	 * interface.  Cap at INT_MAX.
1584 	 */
1585 	retval = MIN(size, INT_MAX);
1586 	if (so_copyout(&retval, (void *)arg, sizeof (retval),
1587 	    (mode & (int)FKIOCTL))) {
1588 		return (EFAULT);
1589 	} else {
1590 		*rvalp = count;
1591 		return (0);
1592 	}
1593 }
1594 
1595 /*
1596  * Process STREAM ioctls.
1597  *
1598  * Returns:
1599  *   < 0  - ioctl was not handle
1600  *  >= 0  - ioctl was handled, if > 0, then it is an errno
1601  */
1602 int
1603 socket_strioc_common(struct sonode *so, int cmd, intptr_t arg, int mode,
1604     struct cred *cr, int32_t *rvalp)
1605 {
1606 	int retval;
1607 
1608 	/* Only STREAM iotcls are handled here */
1609 	if ((cmd & 0xffffff00U) != STR)
1610 		return (-1);
1611 
1612 	switch (cmd) {
1613 	case I_CANPUT:
1614 		/*
1615 		 * We return an error for I_CANPUT so that isastream(3C) will
1616 		 * not report the socket as being a STREAM.
1617 		 */
1618 		return (EOPNOTSUPP);
1619 	case I_NREAD:
1620 		/* Avoid doing a fallback for I_NREAD. */
1621 		return (so_strioc_nread(so, arg, mode, rvalp));
1622 	case I_LOOK:
1623 		/* Avoid doing a fallback for I_LOOK. */
1624 		if (so_copyout("sockmod", (void *)arg, strlen("sockmod") + 1,
1625 		    (mode & (int)FKIOCTL))) {
1626 			return (EFAULT);
1627 		}
1628 		return (0);
1629 	default:
1630 		break;
1631 	}
1632 
1633 	/*
1634 	 * Try to fall back to TPI, and if successful, reissue the ioctl.
1635 	 */
1636 	if ((retval = so_tpi_fallback(so, cr)) == 0) {
1637 		/* Reissue the ioctl */
1638 		ASSERT(so->so_rcv_q_head == NULL);
1639 		return (SOP_IOCTL(so, cmd, arg, mode, cr, rvalp));
1640 	} else {
1641 		return (retval);
1642 	}
1643 }
1644 
1645 int
1646 socket_getopt_common(struct sonode *so, int level, int option_name,
1647     void *optval, socklen_t *optlenp, int flags)
1648 {
1649 	if (level != SOL_SOCKET)
1650 		return (-1);
1651 
1652 	switch (option_name) {
1653 	case SO_ERROR:
1654 	case SO_DOMAIN:
1655 	case SO_TYPE:
1656 	case SO_ACCEPTCONN: {
1657 		int32_t value;
1658 		socklen_t optlen = *optlenp;
1659 
1660 		if (optlen < (t_uscalar_t)sizeof (int32_t)) {
1661 			return (EINVAL);
1662 		}
1663 
1664 		switch (option_name) {
1665 		case SO_ERROR:
1666 			mutex_enter(&so->so_lock);
1667 			value = sogeterr(so, B_TRUE);
1668 			mutex_exit(&so->so_lock);
1669 			break;
1670 		case SO_DOMAIN:
1671 			value = so->so_family;
1672 			break;
1673 		case SO_TYPE:
1674 			value = so->so_type;
1675 			break;
1676 		case SO_ACCEPTCONN:
1677 			if (so->so_state & SS_ACCEPTCONN)
1678 				value = SO_ACCEPTCONN;
1679 			else
1680 				value = 0;
1681 			break;
1682 		}
1683 
1684 		bcopy(&value, optval, sizeof (value));
1685 		*optlenp = sizeof (value);
1686 
1687 		return (0);
1688 	}
1689 	case SO_SNDTIMEO:
1690 	case SO_RCVTIMEO: {
1691 		clock_t value;
1692 		socklen_t optlen = *optlenp;
1693 
1694 		if (get_udatamodel() == DATAMODEL_NONE ||
1695 		    get_udatamodel() == DATAMODEL_NATIVE) {
1696 			if (optlen < sizeof (struct timeval))
1697 				return (EINVAL);
1698 		} else {
1699 			if (optlen < sizeof (struct timeval32))
1700 				return (EINVAL);
1701 		}
1702 		if (option_name == SO_RCVTIMEO)
1703 			value = drv_hztousec(so->so_rcvtimeo);
1704 		else
1705 			value = drv_hztousec(so->so_sndtimeo);
1706 
1707 		if (get_udatamodel() == DATAMODEL_NONE ||
1708 		    get_udatamodel() == DATAMODEL_NATIVE) {
1709 			((struct timeval *)(optval))->tv_sec =
1710 			    value / (1000 * 1000);
1711 			((struct timeval *)(optval))->tv_usec =
1712 			    value % (1000 * 1000);
1713 			*optlenp = sizeof (struct timeval);
1714 		} else {
1715 			((struct timeval32 *)(optval))->tv_sec =
1716 			    value / (1000 * 1000);
1717 			((struct timeval32 *)(optval))->tv_usec =
1718 			    value % (1000 * 1000);
1719 			*optlenp = sizeof (struct timeval32);
1720 		}
1721 		return (0);
1722 	}
1723 	case SO_DEBUG:
1724 	case SO_REUSEADDR:
1725 	case SO_KEEPALIVE:
1726 	case SO_DONTROUTE:
1727 	case SO_BROADCAST:
1728 	case SO_USELOOPBACK:
1729 	case SO_OOBINLINE:
1730 	case SO_SNDBUF:
1731 #ifdef notyet
1732 	case SO_SNDLOWAT:
1733 	case SO_RCVLOWAT:
1734 #endif /* notyet */
1735 	case SO_DGRAM_ERRIND: {
1736 		socklen_t optlen = *optlenp;
1737 
1738 		if (optlen < (t_uscalar_t)sizeof (int32_t))
1739 			return (EINVAL);
1740 		break;
1741 	}
1742 	case SO_RCVBUF: {
1743 		socklen_t optlen = *optlenp;
1744 
1745 		if (optlen < (t_uscalar_t)sizeof (int32_t))
1746 			return (EINVAL);
1747 
1748 		if ((flags & _SOGETSOCKOPT_XPG4_2) && so->so_xpg_rcvbuf != 0) {
1749 			/*
1750 			 * XXX If SO_RCVBUF has been set and this is an
1751 			 * XPG 4.2 application then do not ask the transport
1752 			 * since the transport might adjust the value and not
1753 			 * return exactly what was set by the application.
1754 			 * For non-XPG 4.2 application we return the value
1755 			 * that the transport is actually using.
1756 			 */
1757 			*(int32_t *)optval = so->so_xpg_rcvbuf;
1758 			*optlenp = sizeof (so->so_xpg_rcvbuf);
1759 			return (0);
1760 		}
1761 		/*
1762 		 * If the option has not been set then get a default
1763 		 * value from the transport.
1764 		 */
1765 		break;
1766 	}
1767 	case SO_LINGER: {
1768 		socklen_t optlen = *optlenp;
1769 
1770 		if (optlen < (t_uscalar_t)sizeof (struct linger))
1771 			return (EINVAL);
1772 		break;
1773 	}
1774 	case SO_SND_BUFINFO: {
1775 		socklen_t optlen = *optlenp;
1776 
1777 		if (optlen < (t_uscalar_t)sizeof (struct so_snd_bufinfo))
1778 			return (EINVAL);
1779 		((struct so_snd_bufinfo *)(optval))->sbi_wroff =
1780 		    (so->so_proto_props).sopp_wroff;
1781 		((struct so_snd_bufinfo *)(optval))->sbi_maxblk =
1782 		    (so->so_proto_props).sopp_maxblk;
1783 		((struct so_snd_bufinfo *)(optval))->sbi_maxpsz =
1784 		    (so->so_proto_props).sopp_maxpsz;
1785 		((struct so_snd_bufinfo *)(optval))->sbi_tail =
1786 		    (so->so_proto_props).sopp_tail;
1787 		*optlenp = sizeof (struct so_snd_bufinfo);
1788 		return (0);
1789 	}
1790 	default:
1791 		break;
1792 	}
1793 
1794 	/* Unknown Option */
1795 	return (-1);
1796 }
1797 
1798 void
1799 socket_sonode_destroy(struct sonode *so)
1800 {
1801 	sonode_fini(so);
1802 	kmem_cache_free(socket_cache, so);
1803 }
1804 
1805 int
1806 so_zcopy_wait(struct sonode *so)
1807 {
1808 	int error = 0;
1809 
1810 	mutex_enter(&so->so_lock);
1811 	while (!(so->so_copyflag & STZCNOTIFY)) {
1812 		if (so->so_state & SS_CLOSING) {
1813 			mutex_exit(&so->so_lock);
1814 			return (EINTR);
1815 		}
1816 		if (cv_wait_sig(&so->so_copy_cv, &so->so_lock) == 0) {
1817 			error = EINTR;
1818 			break;
1819 		}
1820 	}
1821 	so->so_copyflag &= ~STZCNOTIFY;
1822 	mutex_exit(&so->so_lock);
1823 	return (error);
1824 }
1825 
1826 void
1827 so_timer_callback(void *arg)
1828 {
1829 	struct sonode *so = (struct sonode *)arg;
1830 
1831 	mutex_enter(&so->so_lock);
1832 
1833 	so->so_rcv_timer_tid = 0;
1834 	if (so->so_rcv_queued > 0) {
1835 		so_notify_data(so, so->so_rcv_queued);
1836 	} else {
1837 		mutex_exit(&so->so_lock);
1838 	}
1839 }
1840 
1841 #ifdef DEBUG
1842 /*
1843  * Verify that the length stored in so_rcv_queued and the length of data blocks
1844  * queued is same.
1845  */
1846 static boolean_t
1847 so_check_length(sonode_t *so)
1848 {
1849 	mblk_t *mp = so->so_rcv_q_head;
1850 	int len = 0;
1851 
1852 	ASSERT(MUTEX_HELD(&so->so_lock));
1853 
1854 	if (mp != NULL) {
1855 		len = msgdsize(mp);
1856 		while ((mp = mp->b_next) != NULL)
1857 			len += msgdsize(mp);
1858 	}
1859 	mp = so->so_rcv_head;
1860 	if (mp != NULL) {
1861 		len += msgdsize(mp);
1862 		while ((mp = mp->b_next) != NULL)
1863 			len += msgdsize(mp);
1864 	}
1865 	return ((len == so->so_rcv_queued) ? B_TRUE : B_FALSE);
1866 }
1867 #endif
1868 
1869 int
1870 so_get_mod_version(struct sockparams *sp)
1871 {
1872 	ASSERT(sp != NULL && sp->sp_smod_info != NULL);
1873 	return (sp->sp_smod_info->smod_version);
1874 }
1875 
1876 /*
1877  * so_start_fallback()
1878  *
1879  * Block new socket operations from coming in, and wait for active operations
1880  * to complete. Threads that are sleeping will be woken up so they can get
1881  * out of the way.
1882  *
1883  * The caller must be a reader on so_fallback_rwlock.
1884  */
1885 static boolean_t
1886 so_start_fallback(struct sonode *so)
1887 {
1888 	ASSERT(RW_READ_HELD(&so->so_fallback_rwlock));
1889 
1890 	mutex_enter(&so->so_lock);
1891 	if (so->so_state & SS_FALLBACK_PENDING) {
1892 		mutex_exit(&so->so_lock);
1893 		return (B_FALSE);
1894 	}
1895 	so->so_state |= SS_FALLBACK_PENDING;
1896 	/*
1897 	 * Poke all threads that might be sleeping. Any operation that comes
1898 	 * in after the cv_broadcast will observe the fallback pending flag
1899 	 * which cause the call to return where it would normally sleep.
1900 	 */
1901 	cv_broadcast(&so->so_state_cv);		/* threads in connect() */
1902 	cv_broadcast(&so->so_rcv_cv);		/* threads in recvmsg() */
1903 	cv_broadcast(&so->so_snd_cv);		/* threads in sendmsg() */
1904 	mutex_enter(&so->so_acceptq_lock);
1905 	cv_broadcast(&so->so_acceptq_cv);	/* threads in accept() */
1906 	mutex_exit(&so->so_acceptq_lock);
1907 	mutex_exit(&so->so_lock);
1908 
1909 	/*
1910 	 * The main reason for the rw_tryupgrade call is to provide
1911 	 * observability during the fallback process. We want to
1912 	 * be able to see if there are pending operations.
1913 	 */
1914 	if (rw_tryupgrade(&so->so_fallback_rwlock) == 0) {
1915 		/*
1916 		 * It is safe to drop and reaquire the fallback lock, because
1917 		 * we are guaranteed that another fallback cannot take place.
1918 		 */
1919 		rw_exit(&so->so_fallback_rwlock);
1920 		DTRACE_PROBE1(pending__ops__wait, (struct sonode *), so);
1921 		rw_enter(&so->so_fallback_rwlock, RW_WRITER);
1922 		DTRACE_PROBE1(pending__ops__complete, (struct sonode *), so);
1923 	}
1924 
1925 	return (B_TRUE);
1926 }
1927 
1928 /*
1929  * so_end_fallback()
1930  *
1931  * Allow socket opertions back in.
1932  *
1933  * The caller must be a writer on so_fallback_rwlock.
1934  */
1935 static void
1936 so_end_fallback(struct sonode *so)
1937 {
1938 	ASSERT(RW_ISWRITER(&so->so_fallback_rwlock));
1939 
1940 	mutex_enter(&so->so_lock);
1941 	so->so_state &= ~(SS_FALLBACK_PENDING|SS_FALLBACK_DRAIN);
1942 	mutex_exit(&so->so_lock);
1943 
1944 	rw_downgrade(&so->so_fallback_rwlock);
1945 }
1946 
1947 /*
1948  * so_quiesced_cb()
1949  *
1950  * Callback passed to the protocol during fallback. It is called once
1951  * the endpoint is quiescent.
1952  *
1953  * No requests from the user, no notifications from the protocol, so it
1954  * is safe to synchronize the state. Data can also be moved without
1955  * risk for reordering.
1956  *
1957  * We do not need to hold so_lock, since there can be only one thread
1958  * operating on the sonode.
1959  */
1960 static void
1961 so_quiesced_cb(sock_upper_handle_t sock_handle, queue_t *q,
1962     struct T_capability_ack *tcap, struct sockaddr *laddr, socklen_t laddrlen,
1963     struct sockaddr *faddr, socklen_t faddrlen, short opts)
1964 {
1965 	struct sonode *so = (struct sonode *)sock_handle;
1966 	boolean_t atmark;
1967 
1968 	sotpi_update_state(so, tcap, laddr, laddrlen, faddr, faddrlen, opts);
1969 
1970 	/*
1971 	 * Some protocols do not quiece the data path during fallback. Once
1972 	 * we set the SS_FALLBACK_DRAIN flag any attempt to queue data will
1973 	 * fail and the protocol is responsible for saving the data for later
1974 	 * delivery (i.e., once the fallback has completed).
1975 	 */
1976 	mutex_enter(&so->so_lock);
1977 	so->so_state |= SS_FALLBACK_DRAIN;
1978 	SOCKET_TIMER_CANCEL(so);
1979 	mutex_exit(&so->so_lock);
1980 
1981 	if (so->so_rcv_head != NULL) {
1982 		if (so->so_rcv_q_last_head == NULL)
1983 			so->so_rcv_q_head = so->so_rcv_head;
1984 		else
1985 			so->so_rcv_q_last_head->b_next = so->so_rcv_head;
1986 		so->so_rcv_q_last_head = so->so_rcv_last_head;
1987 	}
1988 
1989 	atmark = (so->so_state & SS_RCVATMARK) != 0;
1990 	/*
1991 	 * Clear any OOB state having to do with pending data. The TPI
1992 	 * code path will set the appropriate oob state when we move the
1993 	 * oob data to the STREAM head. We leave SS_HADOOBDATA since the oob
1994 	 * data has already been consumed.
1995 	 */
1996 	so->so_state &= ~(SS_RCVATMARK|SS_OOBPEND|SS_HAVEOOBDATA);
1997 
1998 	ASSERT(so->so_oobmsg != NULL || so->so_oobmark <= so->so_rcv_queued);
1999 
2000 	/*
2001 	 * Move data to the STREAM head.
2002 	 */
2003 	while (so->so_rcv_q_head != NULL) {
2004 		mblk_t *mp = so->so_rcv_q_head;
2005 		size_t mlen = msgdsize(mp);
2006 
2007 		so->so_rcv_q_head = mp->b_next;
2008 		mp->b_next = NULL;
2009 		mp->b_prev = NULL;
2010 
2011 		/*
2012 		 * Send T_EXDATA_IND if we are at the oob mark.
2013 		 */
2014 		if (atmark) {
2015 			struct T_exdata_ind *tei;
2016 			mblk_t *mp1 = SOTOTPI(so)->sti_exdata_mp;
2017 
2018 			SOTOTPI(so)->sti_exdata_mp = NULL;
2019 			ASSERT(mp1 != NULL);
2020 			mp1->b_datap->db_type = M_PROTO;
2021 			tei = (struct T_exdata_ind *)mp1->b_rptr;
2022 			tei->PRIM_type = T_EXDATA_IND;
2023 			tei->MORE_flag = 0;
2024 			mp1->b_wptr = (uchar_t *)&tei[1];
2025 
2026 			if (IS_SO_OOB_INLINE(so)) {
2027 				mp1->b_cont = mp;
2028 			} else {
2029 				ASSERT(so->so_oobmsg != NULL);
2030 				mp1->b_cont = so->so_oobmsg;
2031 				so->so_oobmsg = NULL;
2032 
2033 				/* process current mp next time around */
2034 				mp->b_next = so->so_rcv_q_head;
2035 				so->so_rcv_q_head = mp;
2036 				mlen = 0;
2037 			}
2038 			mp = mp1;
2039 
2040 			/* we have consumed the oob mark */
2041 			atmark = B_FALSE;
2042 		} else if (so->so_oobmark > 0) {
2043 			/*
2044 			 * Check if the OOB mark is within the current
2045 			 * mblk chain. In that case we have to split it up.
2046 			 */
2047 			if (so->so_oobmark < mlen) {
2048 				mblk_t *urg_mp = mp;
2049 
2050 				atmark = B_TRUE;
2051 				mp = NULL;
2052 				mlen = so->so_oobmark;
2053 
2054 				/*
2055 				 * It is assumed that the OOB mark does
2056 				 * not land within a mblk.
2057 				 */
2058 				do {
2059 					so->so_oobmark -= MBLKL(urg_mp);
2060 					mp = urg_mp;
2061 					urg_mp = urg_mp->b_cont;
2062 				} while (so->so_oobmark > 0);
2063 				mp->b_cont = NULL;
2064 				if (urg_mp != NULL) {
2065 					urg_mp->b_next = so->so_rcv_q_head;
2066 					so->so_rcv_q_head = urg_mp;
2067 				}
2068 			} else {
2069 				so->so_oobmark -= mlen;
2070 				if (so->so_oobmark == 0)
2071 					atmark = B_TRUE;
2072 			}
2073 		}
2074 
2075 		/*
2076 		 * Queue data on the STREAM head.
2077 		 */
2078 		so->so_rcv_queued -= mlen;
2079 		putnext(q, mp);
2080 	}
2081 	so->so_rcv_head = NULL;
2082 	so->so_rcv_last_head = NULL;
2083 	so->so_rcv_q_head = NULL;
2084 	so->so_rcv_q_last_head = NULL;
2085 
2086 	/*
2087 	 * Check if the oob byte is at the end of the data stream, or if the
2088 	 * oob byte has not yet arrived. In the latter case we have to send a
2089 	 * SIGURG and a mark indicator to the STREAM head. The mark indicator
2090 	 * is needed to guarantee correct behavior for SIOCATMARK. See block
2091 	 * comment in socktpi.h for more details.
2092 	 */
2093 	if (atmark || so->so_oobmark > 0) {
2094 		mblk_t *mp;
2095 
2096 		if (atmark && so->so_oobmsg != NULL) {
2097 			struct T_exdata_ind *tei;
2098 
2099 			mp = SOTOTPI(so)->sti_exdata_mp;
2100 			SOTOTPI(so)->sti_exdata_mp = NULL;
2101 			ASSERT(mp != NULL);
2102 			mp->b_datap->db_type = M_PROTO;
2103 			tei = (struct T_exdata_ind *)mp->b_rptr;
2104 			tei->PRIM_type = T_EXDATA_IND;
2105 			tei->MORE_flag = 0;
2106 			mp->b_wptr = (uchar_t *)&tei[1];
2107 
2108 			mp->b_cont = so->so_oobmsg;
2109 			so->so_oobmsg = NULL;
2110 
2111 			putnext(q, mp);
2112 		} else {
2113 			/* Send up the signal */
2114 			mp = SOTOTPI(so)->sti_exdata_mp;
2115 			SOTOTPI(so)->sti_exdata_mp = NULL;
2116 			ASSERT(mp != NULL);
2117 			DB_TYPE(mp) = M_PCSIG;
2118 			*mp->b_wptr++ = (uchar_t)SIGURG;
2119 			putnext(q, mp);
2120 
2121 			/* Send up the mark indicator */
2122 			mp = SOTOTPI(so)->sti_urgmark_mp;
2123 			SOTOTPI(so)->sti_urgmark_mp = NULL;
2124 			mp->b_flag = atmark ? MSGMARKNEXT : MSGNOTMARKNEXT;
2125 			putnext(q, mp);
2126 
2127 			so->so_oobmark = 0;
2128 		}
2129 	}
2130 
2131 	if (SOTOTPI(so)->sti_exdata_mp != NULL) {
2132 		freeb(SOTOTPI(so)->sti_exdata_mp);
2133 		SOTOTPI(so)->sti_exdata_mp = NULL;
2134 	}
2135 
2136 	if (SOTOTPI(so)->sti_urgmark_mp != NULL) {
2137 		freeb(SOTOTPI(so)->sti_urgmark_mp);
2138 		SOTOTPI(so)->sti_urgmark_mp = NULL;
2139 	}
2140 
2141 	ASSERT(so->so_oobmark == 0);
2142 	ASSERT(so->so_rcv_queued == 0);
2143 }
2144 
2145 #ifdef DEBUG
2146 /*
2147  * Do an integrity check of the sonode. This should be done if a
2148  * fallback fails after sonode has initially been converted to use
2149  * TPI and subsequently have to be reverted.
2150  *
2151  * Failure to pass the integrity check will panic the system.
2152  */
2153 void
2154 so_integrity_check(struct sonode *cur, struct sonode *orig)
2155 {
2156 	VERIFY(cur->so_vnode == orig->so_vnode);
2157 	VERIFY(cur->so_ops == orig->so_ops);
2158 	/*
2159 	 * For so_state we can only VERIFY the state flags in CHECK_STATE.
2160 	 * The other state flags might be affected by a notification from the
2161 	 * protocol.
2162 	 */
2163 #define	CHECK_STATE	(SS_CANTRCVMORE|SS_CANTSENDMORE|SS_NDELAY|SS_NONBLOCK| \
2164 	SS_ASYNC|SS_ACCEPTCONN|SS_SAVEDEOR|SS_RCVATMARK|SS_OOBPEND| \
2165 	SS_HAVEOOBDATA|SS_HADOOBDATA|SS_SENTLASTREADSIG|SS_SENTLASTWRITESIG)
2166 	VERIFY((cur->so_state & (orig->so_state & CHECK_STATE)) ==
2167 	    (orig->so_state & CHECK_STATE));
2168 	VERIFY(cur->so_mode == orig->so_mode);
2169 	VERIFY(cur->so_flag == orig->so_flag);
2170 	VERIFY(cur->so_count == orig->so_count);
2171 	/* Cannot VERIFY so_proto_connid; proto can update it */
2172 	VERIFY(cur->so_sockparams == orig->so_sockparams);
2173 	/* an error might have been recorded, but it can not be lost */
2174 	VERIFY(cur->so_error != 0 || orig->so_error == 0);
2175 	VERIFY(cur->so_family == orig->so_family);
2176 	VERIFY(cur->so_type == orig->so_type);
2177 	VERIFY(cur->so_protocol == orig->so_protocol);
2178 	VERIFY(cur->so_version == orig->so_version);
2179 	/* New conns might have arrived, but none should have been lost */
2180 	VERIFY(cur->so_acceptq_len >= orig->so_acceptq_len);
2181 	VERIFY(cur->so_acceptq_head == orig->so_acceptq_head);
2182 	VERIFY(cur->so_backlog == orig->so_backlog);
2183 	/* New OOB migth have arrived, but mark should not have been lost */
2184 	VERIFY(cur->so_oobmark >= orig->so_oobmark);
2185 	/* Cannot VERIFY so_oobmsg; the proto might have sent up a new one */
2186 	VERIFY(cur->so_pgrp == orig->so_pgrp);
2187 	VERIFY(cur->so_peercred == orig->so_peercred);
2188 	VERIFY(cur->so_cpid == orig->so_cpid);
2189 	VERIFY(cur->so_zoneid == orig->so_zoneid);
2190 	/* New data migth have arrived, but none should have been lost */
2191 	VERIFY(cur->so_rcv_queued >= orig->so_rcv_queued);
2192 	VERIFY(cur->so_rcv_q_head == orig->so_rcv_q_head);
2193 	VERIFY(cur->so_rcv_head == orig->so_rcv_head);
2194 	VERIFY(cur->so_proto_handle == orig->so_proto_handle);
2195 	VERIFY(cur->so_downcalls == orig->so_downcalls);
2196 	/* Cannot VERIFY so_proto_props; they can be updated by proto */
2197 }
2198 #endif
2199 
2200 /*
2201  * so_tpi_fallback()
2202  *
2203  * This is the fallback initation routine; things start here.
2204  *
2205  * Basic strategy:
2206  *   o Block new socket operations from coming in
2207  *   o Allocate/initate info needed by TPI
2208  *   o Quiesce the connection, at which point we sync
2209  *     state and move data
2210  *   o Change operations (sonodeops) associated with the socket
2211  *   o Unblock threads waiting for the fallback to finish
2212  */
2213 int
2214 so_tpi_fallback(struct sonode *so, struct cred *cr)
2215 {
2216 	int error;
2217 	queue_t *q;
2218 	struct sockparams *sp;
2219 	struct sockparams *newsp = NULL;
2220 	so_proto_fallback_func_t fbfunc;
2221 	boolean_t direct;
2222 	struct sonode *nso;
2223 #ifdef DEBUG
2224 	struct sonode origso;
2225 #endif
2226 	error = 0;
2227 	sp = so->so_sockparams;
2228 	fbfunc = sp->sp_smod_info->smod_proto_fallback_func;
2229 
2230 	/*
2231 	 * Fallback can only happen if there is a device associated
2232 	 * with the sonode, and the socket module has a fallback function.
2233 	 */
2234 	if (!SOCKPARAMS_HAS_DEVICE(sp) || fbfunc == NULL)
2235 		return (EINVAL);
2236 
2237 	/*
2238 	 * Initiate fallback; upon success we know that no new requests
2239 	 * will come in from the user.
2240 	 */
2241 	if (!so_start_fallback(so))
2242 		return (EAGAIN);
2243 #ifdef DEBUG
2244 	/*
2245 	 * Make a copy of the sonode in case we need to make an integrity
2246 	 * check later on.
2247 	 */
2248 	bcopy(so, &origso, sizeof (*so));
2249 #endif
2250 
2251 	sp->sp_stats.sps_nfallback.value.ui64++;
2252 
2253 	newsp = sockparams_hold_ephemeral_bydev(so->so_family, so->so_type,
2254 	    so->so_protocol, so->so_sockparams->sp_sdev_info.sd_devpath,
2255 	    KM_SLEEP, &error);
2256 	if (error != 0)
2257 		goto out;
2258 
2259 	if (so->so_direct != NULL) {
2260 		sodirect_t *sodp = so->so_direct;
2261 		mutex_enter(&so->so_lock);
2262 
2263 		so->so_direct->sod_enabled = B_FALSE;
2264 		so->so_state &= ~SS_SODIRECT;
2265 		ASSERT(sodp->sod_uioafh == NULL);
2266 		mutex_exit(&so->so_lock);
2267 	}
2268 
2269 	/* Turn sonode into a TPI socket */
2270 	error = sotpi_convert_sonode(so, newsp, &direct, &q, cr);
2271 	if (error != 0)
2272 		goto out;
2273 
2274 
2275 	/*
2276 	 * Now tell the protocol to start using TPI. so_quiesced_cb be
2277 	 * called once it's safe to synchronize state.
2278 	 */
2279 	DTRACE_PROBE1(proto__fallback__begin, struct sonode *, so);
2280 	error = (*fbfunc)(so->so_proto_handle, q, direct, so_quiesced_cb);
2281 	DTRACE_PROBE1(proto__fallback__end, struct sonode *, so);
2282 
2283 	if (error != 0) {
2284 		/* protocol was unable to do a fallback, revert the sonode */
2285 		sotpi_revert_sonode(so, cr);
2286 		goto out;
2287 	}
2288 
2289 	/*
2290 	 * Walk the accept queue and notify the proto that they should
2291 	 * fall back to TPI. The protocol will send up the T_CONN_IND.
2292 	 */
2293 	nso = so->so_acceptq_head;
2294 	while (nso != NULL) {
2295 		int rval;
2296 
2297 		DTRACE_PROBE1(proto__fallback__begin, struct sonode *, nso);
2298 		rval = (*fbfunc)(nso->so_proto_handle, NULL, direct, NULL);
2299 		DTRACE_PROBE1(proto__fallback__end, struct sonode *, nso);
2300 		if (rval != 0) {
2301 			zcmn_err(getzoneid(), CE_WARN,
2302 			    "Failed to convert socket in accept queue to TPI. "
2303 			    "Pid = %d\n", curproc->p_pid);
2304 		}
2305 		nso = nso->so_acceptq_next;
2306 	}
2307 
2308 	/*
2309 	 * Now flush the acceptq, this will destroy all sockets. They will
2310 	 * be recreated in sotpi_accept().
2311 	 */
2312 	so_acceptq_flush(so);
2313 
2314 	mutex_enter(&so->so_lock);
2315 	so->so_state |= SS_FALLBACK_COMP;
2316 	mutex_exit(&so->so_lock);
2317 
2318 	/*
2319 	 * Swap the sonode ops. Socket opertations that come in once this
2320 	 * is done will proceed without blocking.
2321 	 */
2322 	so->so_ops = &sotpi_sonodeops;
2323 
2324 	/*
2325 	 * Wake up any threads stuck in poll. This is needed since the poll
2326 	 * head changes when the fallback happens (moves from the sonode to
2327 	 * the STREAMS head).
2328 	 */
2329 	pollwakeup(&so->so_poll_list, POLLERR);
2330 out:
2331 	so_end_fallback(so);
2332 
2333 	if (error != 0) {
2334 #ifdef DEBUG
2335 		so_integrity_check(so, &origso);
2336 #endif
2337 		zcmn_err(getzoneid(), CE_WARN,
2338 		    "Failed to convert socket to TPI (err=%d). Pid = %d\n",
2339 		    error, curproc->p_pid);
2340 		if (newsp != NULL)
2341 			SOCKPARAMS_DEC_REF(newsp);
2342 	}
2343 
2344 	return (error);
2345 }
2346