xref: /dragonfly/lib/libdmsg/msg.c (revision 655933d6)
1 /*
2  * Copyright (c) 2011-2015 The DragonFly Project.  All rights reserved.
3  *
4  * This code is derived from software contributed to The DragonFly Project
5  * by Matthew Dillon <dillon@dragonflybsd.org>
6  * by Venkatesh Srinivas <vsrinivas@dragonflybsd.org>
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  *
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in
16  *    the documentation and/or other materials provided with the
17  *    distribution.
18  * 3. Neither the name of The DragonFly Project nor the names of its
19  *    contributors may be used to endorse or promote products derived
20  *    from this software without specific, prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
23  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
24  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
25  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
26  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
27  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
28  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
29  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
30  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
31  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
32  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 #include "dmsg_local.h"
37 
38 #define DMSG_BLOCK_DEBUG
39 
40 int DMsgDebugOpt;
41 static unsigned int dmsg_state_count;
42 #ifdef DMSG_BLOCK_DEBUG
43 static unsigned int biocount;
44 #endif
45 
46 static int dmsg_state_msgrx(dmsg_msg_t *msg, int mstate);
47 static void dmsg_state_cleanuptx(dmsg_iocom_t *iocom, dmsg_msg_t *msg);
48 static void dmsg_msg_free_locked(dmsg_msg_t *msg);
49 static void dmsg_state_free(dmsg_state_t *state);
50 static void dmsg_subq_delete(dmsg_state_t *state);
51 static void dmsg_simulate_failure(dmsg_state_t *state, int meto, int error);
52 static void dmsg_state_abort(dmsg_state_t *state);
53 static void dmsg_state_dying(dmsg_state_t *state);
54 
55 RB_GENERATE(dmsg_state_tree, dmsg_state, rbnode, dmsg_state_cmp);
56 
57 /*
58  * STATE TREE - Represents open transactions which are indexed by their
59  *		{ msgid } relative to the governing iocom.
60  */
61 int
62 dmsg_state_cmp(dmsg_state_t *state1, dmsg_state_t *state2)
63 {
64 	if (state1->msgid < state2->msgid)
65 		return(-1);
66 	if (state1->msgid > state2->msgid)
67 		return(1);
68 	return(0);
69 }
70 
71 /*
72  * Initialize a low-level ioq
73  */
74 void
75 dmsg_ioq_init(dmsg_iocom_t *iocom __unused, dmsg_ioq_t *ioq)
76 {
77 	bzero(ioq, sizeof(*ioq));
78 	ioq->state = DMSG_MSGQ_STATE_HEADER1;
79 	TAILQ_INIT(&ioq->msgq);
80 }
81 
82 /*
83  * Cleanup queue.
84  *
85  * caller holds iocom->mtx.
86  */
87 void
88 dmsg_ioq_done(dmsg_iocom_t *iocom __unused, dmsg_ioq_t *ioq)
89 {
90 	dmsg_msg_t *msg;
91 
92 	while ((msg = TAILQ_FIRST(&ioq->msgq)) != NULL) {
93 		assert(0);	/* shouldn't happen */
94 		TAILQ_REMOVE(&ioq->msgq, msg, qentry);
95 		dmsg_msg_free(msg);
96 	}
97 	if ((msg = ioq->msg) != NULL) {
98 		ioq->msg = NULL;
99 		dmsg_msg_free(msg);
100 	}
101 }
102 
103 /*
104  * Initialize a low-level communications channel.
105  *
106  * NOTE: The signal_func() is called at least once from the loop and can be
107  *	 re-armed via dmsg_iocom_restate().
108  */
109 void
110 dmsg_iocom_init(dmsg_iocom_t *iocom, int sock_fd, int alt_fd,
111 		   void (*signal_func)(dmsg_iocom_t *iocom),
112 		   void (*rcvmsg_func)(dmsg_msg_t *msg),
113 		   void (*usrmsg_func)(dmsg_msg_t *msg, int unmanaged),
114 		   void (*altmsg_func)(dmsg_iocom_t *iocom))
115 {
116 	struct stat st;
117 
118 	bzero(iocom, sizeof(*iocom));
119 
120 	asprintf(&iocom->label, "iocom-%p", iocom);
121 	iocom->signal_callback = signal_func;
122 	iocom->rcvmsg_callback = rcvmsg_func;
123 	iocom->altmsg_callback = altmsg_func;
124 	iocom->usrmsg_callback = usrmsg_func;
125 
126 	pthread_mutex_init(&iocom->mtx, NULL);
127 	RB_INIT(&iocom->staterd_tree);
128 	RB_INIT(&iocom->statewr_tree);
129 	TAILQ_INIT(&iocom->txmsgq);
130 	iocom->sock_fd = sock_fd;
131 	iocom->alt_fd = alt_fd;
132 	iocom->flags = DMSG_IOCOMF_RREQ | DMSG_IOCOMF_CLOSEALT;
133 	if (signal_func)
134 		iocom->flags |= DMSG_IOCOMF_SWORK;
135 	dmsg_ioq_init(iocom, &iocom->ioq_rx);
136 	dmsg_ioq_init(iocom, &iocom->ioq_tx);
137 	iocom->state0.refs = 1;		/* should never trigger a free */
138 	iocom->state0.iocom = iocom;
139 	iocom->state0.parent = &iocom->state0;
140 	iocom->state0.flags = DMSG_STATE_ROOT;
141 	TAILQ_INIT(&iocom->state0.subq);
142 
143 	if (pipe(iocom->wakeupfds) < 0)
144 		assert(0);
145 	fcntl(iocom->wakeupfds[0], F_SETFL, O_NONBLOCK);
146 	fcntl(iocom->wakeupfds[1], F_SETFL, O_NONBLOCK);
147 
148 	/*
149 	 * Negotiate session crypto synchronously.  This will mark the
150 	 * connection as error'd if it fails.  If this is a pipe it's
151 	 * a linkage that we set up ourselves to the filesystem and there
152 	 * is no crypto.
153 	 */
154 	if (fstat(sock_fd, &st) < 0)
155 		assert(0);
156 	if (S_ISSOCK(st.st_mode))
157 		dmsg_crypto_negotiate(iocom);
158 
159 	/*
160 	 * Make sure our fds are set to non-blocking for the iocom core.
161 	 */
162 	if (sock_fd >= 0)
163 		fcntl(sock_fd, F_SETFL, O_NONBLOCK);
164 #if 0
165 	/* if line buffered our single fgets() should be fine */
166 	if (alt_fd >= 0)
167 		fcntl(alt_fd, F_SETFL, O_NONBLOCK);
168 #endif
169 }
170 
171 void
172 dmsg_iocom_label(dmsg_iocom_t *iocom, const char *ctl, ...)
173 {
174 	va_list va;
175 	char *optr;
176 
177 	va_start(va, ctl);
178 	optr = iocom->label;
179 	vasprintf(&iocom->label, ctl, va);
180 	va_end(va);
181 	if (optr)
182 		free(optr);
183 }
184 
185 /*
186  * May only be called from a callback from iocom_core.
187  *
188  * Adjust state machine functions, set flags to guarantee that both
189  * the recevmsg_func and the sendmsg_func is called at least once.
190  */
191 void
192 dmsg_iocom_restate(dmsg_iocom_t *iocom,
193 		   void (*signal_func)(dmsg_iocom_t *),
194 		   void (*rcvmsg_func)(dmsg_msg_t *msg))
195 {
196 	pthread_mutex_lock(&iocom->mtx);
197 	iocom->signal_callback = signal_func;
198 	iocom->rcvmsg_callback = rcvmsg_func;
199 	if (signal_func)
200 		atomic_set_int(&iocom->flags, DMSG_IOCOMF_SWORK);
201 	else
202 		atomic_clear_int(&iocom->flags, DMSG_IOCOMF_SWORK);
203 	pthread_mutex_unlock(&iocom->mtx);
204 }
205 
206 void
207 dmsg_iocom_signal(dmsg_iocom_t *iocom)
208 {
209 	pthread_mutex_lock(&iocom->mtx);
210 	if (iocom->signal_callback)
211 		atomic_set_int(&iocom->flags, DMSG_IOCOMF_SWORK);
212 	pthread_mutex_unlock(&iocom->mtx);
213 }
214 
215 /*
216  * Cleanup a terminating iocom.
217  *
218  * Caller should not hold iocom->mtx.  The iocom has already been disconnected
219  * from all possible references to it.
220  */
221 void
222 dmsg_iocom_done(dmsg_iocom_t *iocom)
223 {
224 	dmsg_crypto_terminate(iocom);
225 	if (iocom->sock_fd >= 0) {
226 		close(iocom->sock_fd);
227 		iocom->sock_fd = -1;
228 	}
229 	if (iocom->alt_fd >= 0 && (iocom->flags & DMSG_IOCOMF_CLOSEALT)) {
230 		close(iocom->alt_fd);
231 		iocom->alt_fd = -1;
232 	}
233 	dmsg_ioq_done(iocom, &iocom->ioq_rx);
234 	dmsg_ioq_done(iocom, &iocom->ioq_tx);
235 	if (iocom->wakeupfds[0] >= 0) {
236 		close(iocom->wakeupfds[0]);
237 		iocom->wakeupfds[0] = -1;
238 	}
239 	if (iocom->wakeupfds[1] >= 0) {
240 		close(iocom->wakeupfds[1]);
241 		iocom->wakeupfds[1] = -1;
242 	}
243 	pthread_mutex_destroy(&iocom->mtx);
244 }
245 
246 /*
247  * Allocate a new message using the specified transaction state.
248  *
249  * If CREATE is set a new transaction is allocated relative to the passed-in
250  * transaction (the 'state' argument becomes pstate).
251  *
252  * If CREATE is not set the message is associated with the passed-in
253  * transaction.
254  */
255 dmsg_msg_t *
256 dmsg_msg_alloc(dmsg_state_t *state,
257 	       size_t aux_size, uint32_t cmd,
258 	       void (*func)(dmsg_msg_t *), void *data)
259 {
260 	dmsg_iocom_t *iocom = state->iocom;
261 	dmsg_msg_t *msg;
262 
263 	pthread_mutex_lock(&iocom->mtx);
264 	msg = dmsg_msg_alloc_locked(state, aux_size, cmd, func, data);
265 	pthread_mutex_unlock(&iocom->mtx);
266 
267 	return msg;
268 }
269 
270 dmsg_msg_t *
271 dmsg_msg_alloc_locked(dmsg_state_t *state,
272 	       size_t aux_size, uint32_t cmd,
273 	       void (*func)(dmsg_msg_t *), void *data)
274 {
275 	dmsg_iocom_t *iocom = state->iocom;
276 	dmsg_state_t *pstate;
277 	dmsg_msg_t *msg;
278 	int hbytes;
279 	size_t aligned_size;
280 
281 	aligned_size = DMSG_DOALIGN(aux_size);
282 	if ((cmd & (DMSGF_CREATE | DMSGF_REPLY)) == DMSGF_CREATE) {
283 		/*
284 		 * When CREATE is set without REPLY the caller is
285 		 * initiating a new transaction stacked under the specified
286 		 * circuit.
287 		 *
288 		 * It is possible to race a circuit failure, inherit the
289 		 * parent's STATE_DYING flag to trigger an abort sequence
290 		 * in the transmit path.  By not inheriting ABORTING the
291 		 * abort sequence can recurse.
292 		 *
293 		 * NOTE: CREATE in txcmd handled by dmsg_msg_write()
294 		 * NOTE: DELETE in txcmd handled by dmsg_state_cleanuptx()
295 		 */
296 		pstate = state;
297 		state = malloc(sizeof(*state));
298 		bzero(state, sizeof(*state));
299 		atomic_add_int(&dmsg_state_count, 1);
300 
301 		TAILQ_INIT(&state->subq);
302 		state->parent = pstate;
303 		state->iocom = iocom;
304 		state->flags = DMSG_STATE_DYNAMIC;
305 		state->msgid = (uint64_t)(uintptr_t)state;
306 		state->txcmd = cmd & ~(DMSGF_CREATE | DMSGF_DELETE);
307 		state->rxcmd = DMSGF_REPLY;
308 		state->icmd = state->txcmd & DMSGF_BASECMDMASK;
309 		state->func = func;
310 		state->any.any = data;
311 
312 		state->flags |= DMSG_STATE_SUBINSERTED |
313 				DMSG_STATE_RBINSERTED;
314 		state->flags |= pstate->flags & DMSG_STATE_DYING;
315 		if (TAILQ_EMPTY(&pstate->subq))
316 			dmsg_state_hold(pstate);
317 		RB_INSERT(dmsg_state_tree, &iocom->statewr_tree, state);
318 		TAILQ_INSERT_TAIL(&pstate->subq, state, entry);
319 		dmsg_state_hold(state);		/* state on pstate->subq */
320 		dmsg_state_hold(state);		/* state on rbtree */
321 		dmsg_state_hold(state);		/* msg->state */
322 	} else {
323 		/*
324 		 * Otherwise the message is transmitted over the existing
325 		 * open transaction.
326 		 */
327 		pstate = state->parent;
328 		dmsg_state_hold(state);		/* msg->state */
329 	}
330 
331 	/* XXX SMP race for state */
332 	hbytes = (cmd & DMSGF_SIZE) * DMSG_ALIGN;
333 	assert((size_t)hbytes >= sizeof(struct dmsg_hdr));
334 	msg = malloc(offsetof(struct dmsg_msg, any.head) + hbytes);
335 	bzero(msg, offsetof(struct dmsg_msg, any.head));
336 
337 	/*
338 	 * [re]allocate the auxillary data buffer.  The caller knows that
339 	 * a size-aligned buffer will be allocated but we do not want to
340 	 * force the caller to zero any tail piece, so we do that ourself.
341 	 */
342 	if (msg->aux_size != aux_size) {
343 		if (msg->aux_data) {
344 			free(msg->aux_data);
345 			msg->aux_data = NULL;
346 			msg->aux_size = 0;
347 		}
348 		if (aux_size) {
349 			msg->aux_data = malloc(aligned_size);
350 			msg->aux_size = aux_size;
351 			if (aux_size != aligned_size) {
352 				bzero(msg->aux_data + aux_size,
353 				      aligned_size - aux_size);
354 			}
355 		}
356 	}
357 
358 	/*
359 	 * Set REVTRANS if the transaction was remotely initiated
360 	 * Set REVCIRC if the circuit was remotely initiated
361 	 */
362 	if (state->flags & DMSG_STATE_OPPOSITE)
363 		cmd |= DMSGF_REVTRANS;
364 	if (pstate->flags & DMSG_STATE_OPPOSITE)
365 		cmd |= DMSGF_REVCIRC;
366 
367 	/*
368 	 * Finish filling out the header.
369 	 */
370 	bzero(&msg->any.head, hbytes);
371 	msg->hdr_size = hbytes;
372 	msg->any.head.magic = DMSG_HDR_MAGIC;
373 	msg->any.head.cmd = cmd;
374 	msg->any.head.aux_descr = 0;
375 	msg->any.head.aux_crc = 0;
376 	msg->any.head.msgid = state->msgid;
377 	msg->any.head.circuit = pstate->msgid;
378 	msg->state = state;
379 
380 	return (msg);
381 }
382 
383 /*
384  * Free a message so it can be reused afresh.
385  *
386  * NOTE: aux_size can be 0 with a non-NULL aux_data.
387  */
388 static
389 void
390 dmsg_msg_free_locked(dmsg_msg_t *msg)
391 {
392 	dmsg_state_t *state;
393 
394 	if ((state = msg->state) != NULL) {
395 		dmsg_state_drop(state);
396 		msg->state = NULL;	/* safety */
397 	}
398 	if (msg->aux_data) {
399 		free(msg->aux_data);
400 		msg->aux_data = NULL;	/* safety */
401 	}
402 	msg->aux_size = 0;
403 	free (msg);
404 }
405 
406 void
407 dmsg_msg_free(dmsg_msg_t *msg)
408 {
409 	dmsg_iocom_t *iocom = msg->state->iocom;
410 
411 	pthread_mutex_lock(&iocom->mtx);
412 	dmsg_msg_free_locked(msg);
413 	pthread_mutex_unlock(&iocom->mtx);
414 }
415 
416 /*
417  * I/O core loop for an iocom.
418  *
419  * Thread localized, iocom->mtx not held.
420  */
421 void
422 dmsg_iocom_core(dmsg_iocom_t *iocom)
423 {
424 	struct pollfd fds[3];
425 	char dummybuf[256];
426 	dmsg_msg_t *msg;
427 	int timeout;
428 	int count;
429 	int wi;	/* wakeup pipe */
430 	int si;	/* socket */
431 	int ai;	/* alt bulk path socket */
432 
433 	while ((iocom->flags & DMSG_IOCOMF_EOF) == 0) {
434 		/*
435 		 * These iocom->flags are only manipulated within the
436 		 * context of the current thread.  However, modifications
437 		 * still require atomic ops.
438 		 */
439 		dmio_printf(iocom, 5, "iocom %p %08x\n",
440 			    iocom, iocom->flags);
441 		if ((iocom->flags & (DMSG_IOCOMF_RWORK |
442 				     DMSG_IOCOMF_WWORK |
443 				     DMSG_IOCOMF_PWORK |
444 				     DMSG_IOCOMF_SWORK |
445 				     DMSG_IOCOMF_ARWORK |
446 				     DMSG_IOCOMF_AWWORK)) == 0) {
447 			/*
448 			 * Only poll if no immediate work is pending.
449 			 * Otherwise we are just wasting our time calling
450 			 * poll.
451 			 */
452 			timeout = 5000;
453 
454 			count = 0;
455 			wi = -1;
456 			si = -1;
457 			ai = -1;
458 
459 			/*
460 			 * Always check the inter-thread pipe, e.g.
461 			 * for iocom->txmsgq work.
462 			 */
463 			wi = count++;
464 			fds[wi].fd = iocom->wakeupfds[0];
465 			fds[wi].events = POLLIN;
466 			fds[wi].revents = 0;
467 
468 			/*
469 			 * Check the socket input/output direction as
470 			 * requested
471 			 */
472 			if (iocom->flags & (DMSG_IOCOMF_RREQ |
473 					    DMSG_IOCOMF_WREQ)) {
474 				si = count++;
475 				fds[si].fd = iocom->sock_fd;
476 				fds[si].events = 0;
477 				fds[si].revents = 0;
478 
479 				if (iocom->flags & DMSG_IOCOMF_RREQ)
480 					fds[si].events |= POLLIN;
481 				if (iocom->flags & DMSG_IOCOMF_WREQ)
482 					fds[si].events |= POLLOUT;
483 			}
484 
485 			/*
486 			 * Check the alternative fd for work.
487 			 */
488 			if (iocom->alt_fd >= 0) {
489 				ai = count++;
490 				fds[ai].fd = iocom->alt_fd;
491 				fds[ai].events = POLLIN;
492 				fds[ai].revents = 0;
493 			}
494 			poll(fds, count, timeout);
495 
496 			if (wi >= 0 && (fds[wi].revents & POLLIN))
497 				atomic_set_int(&iocom->flags,
498 					       DMSG_IOCOMF_PWORK);
499 			if (si >= 0 && (fds[si].revents & POLLIN))
500 				atomic_set_int(&iocom->flags,
501 					       DMSG_IOCOMF_RWORK);
502 			if (si >= 0 && (fds[si].revents & POLLOUT))
503 				atomic_set_int(&iocom->flags,
504 					       DMSG_IOCOMF_WWORK);
505 			if (wi >= 0 && (fds[wi].revents & POLLOUT))
506 				atomic_set_int(&iocom->flags,
507 					       DMSG_IOCOMF_WWORK);
508 			if (ai >= 0 && (fds[ai].revents & POLLIN))
509 				atomic_set_int(&iocom->flags,
510 					       DMSG_IOCOMF_ARWORK);
511 		} else {
512 			/*
513 			 * Always check the pipe
514 			 */
515 			atomic_set_int(&iocom->flags, DMSG_IOCOMF_PWORK);
516 		}
517 
518 		if (iocom->flags & DMSG_IOCOMF_SWORK) {
519 			atomic_clear_int(&iocom->flags, DMSG_IOCOMF_SWORK);
520 			iocom->signal_callback(iocom);
521 		}
522 
523 		/*
524 		 * Pending message queues from other threads wake us up
525 		 * with a write to the wakeupfds[] pipe.  We have to clear
526 		 * the pipe with a dummy read.
527 		 */
528 		if (iocom->flags & DMSG_IOCOMF_PWORK) {
529 			atomic_clear_int(&iocom->flags, DMSG_IOCOMF_PWORK);
530 			read(iocom->wakeupfds[0], dummybuf, sizeof(dummybuf));
531 			atomic_set_int(&iocom->flags, DMSG_IOCOMF_RWORK);
532 			atomic_set_int(&iocom->flags, DMSG_IOCOMF_WWORK);
533 		}
534 
535 		/*
536 		 * Message write sequencing
537 		 */
538 		if (iocom->flags & DMSG_IOCOMF_WWORK)
539 			dmsg_iocom_flush1(iocom);
540 
541 		/*
542 		 * Message read sequencing.  Run this after the write
543 		 * sequencing in case the write sequencing allowed another
544 		 * auto-DELETE to occur on the read side.
545 		 */
546 		if (iocom->flags & DMSG_IOCOMF_RWORK) {
547 			while ((iocom->flags & DMSG_IOCOMF_EOF) == 0 &&
548 			       (msg = dmsg_ioq_read(iocom)) != NULL) {
549 				dmio_printf(iocom, 4, "receive %s\n",
550 					    dmsg_msg_str(msg));
551 				iocom->rcvmsg_callback(msg);
552 				pthread_mutex_lock(&iocom->mtx);
553 				dmsg_state_cleanuprx(iocom, msg);
554 				pthread_mutex_unlock(&iocom->mtx);
555 			}
556 		}
557 
558 		if (iocom->flags & DMSG_IOCOMF_ARWORK) {
559 			atomic_clear_int(&iocom->flags, DMSG_IOCOMF_ARWORK);
560 			iocom->altmsg_callback(iocom);
561 		}
562 	}
563 }
564 
565 /*
566  * Make sure there's enough room in the FIFO to hold the
567  * needed data.
568  *
569  * Assume worst case encrypted form is 2x the size of the
570  * plaintext equivalent.
571  */
572 static
573 size_t
574 dmsg_ioq_makeroom(dmsg_ioq_t *ioq, size_t needed)
575 {
576 	size_t bytes;
577 	size_t nmax;
578 
579 	bytes = ioq->fifo_cdx - ioq->fifo_beg;
580 	nmax = sizeof(ioq->buf) - ioq->fifo_end;
581 	if (bytes + nmax / 2 < needed) {
582 		if (bytes) {
583 			bcopy(ioq->buf + ioq->fifo_beg,
584 			      ioq->buf,
585 			      bytes);
586 		}
587 		ioq->fifo_cdx -= ioq->fifo_beg;
588 		ioq->fifo_beg = 0;
589 		if (ioq->fifo_cdn < ioq->fifo_end) {
590 			bcopy(ioq->buf + ioq->fifo_cdn,
591 			      ioq->buf + ioq->fifo_cdx,
592 			      ioq->fifo_end - ioq->fifo_cdn);
593 		}
594 		ioq->fifo_end -= ioq->fifo_cdn - ioq->fifo_cdx;
595 		ioq->fifo_cdn = ioq->fifo_cdx;
596 		nmax = sizeof(ioq->buf) - ioq->fifo_end;
597 	}
598 	return(nmax);
599 }
600 
601 /*
602  * Read the next ready message from the ioq, issuing I/O if needed.
603  * Caller should retry on a read-event when NULL is returned.
604  *
605  * If an error occurs during reception a DMSG_LNK_ERROR msg will
606  * be returned for each open transaction, then the ioq and iocom
607  * will be errored out and a non-transactional DMSG_LNK_ERROR
608  * msg will be returned as the final message.  The caller should not call
609  * us again after the final message is returned.
610  *
611  * Thread localized, iocom->mtx not held.
612  */
613 dmsg_msg_t *
614 dmsg_ioq_read(dmsg_iocom_t *iocom)
615 {
616 	dmsg_ioq_t *ioq = &iocom->ioq_rx;
617 	dmsg_msg_t *msg;
618 	dmsg_hdr_t *head;
619 	ssize_t n;
620 	size_t bytes;
621 	size_t nmax;
622 	uint32_t aux_size;
623 	uint32_t xcrc32;
624 	int error;
625 
626 again:
627 	/*
628 	 * If a message is already pending we can just remove and
629 	 * return it.  Message state has already been processed.
630 	 * (currently not implemented)
631 	 */
632 	if ((msg = TAILQ_FIRST(&ioq->msgq)) != NULL) {
633 		TAILQ_REMOVE(&ioq->msgq, msg, qentry);
634 
635 		if (msg->state == &iocom->state0) {
636 			atomic_set_int(&iocom->flags, DMSG_IOCOMF_EOF);
637 			dmio_printf(iocom, 1,
638 				    "EOF ON SOCKET %d\n",
639 				    iocom->sock_fd);
640 		}
641 		return (msg);
642 	}
643 	atomic_clear_int(&iocom->flags, DMSG_IOCOMF_RREQ | DMSG_IOCOMF_RWORK);
644 
645 	/*
646 	 * If the stream is errored out we stop processing it.
647 	 */
648 	if (ioq->error)
649 		goto skip;
650 
651 	/*
652 	 * Message read in-progress (msg is NULL at the moment).  We don't
653 	 * allocate a msg until we have its core header.
654 	 */
655 	nmax = sizeof(ioq->buf) - ioq->fifo_end;
656 	bytes = ioq->fifo_cdx - ioq->fifo_beg;		/* already decrypted */
657 	msg = ioq->msg;
658 
659 	switch(ioq->state) {
660 	case DMSG_MSGQ_STATE_HEADER1:
661 		/*
662 		 * Load the primary header, fail on any non-trivial read
663 		 * error or on EOF.  Since the primary header is the same
664 		 * size is the message alignment it will never straddle
665 		 * the end of the buffer.
666 		 */
667 		nmax = dmsg_ioq_makeroom(ioq, sizeof(msg->any.head));
668 		if (bytes < sizeof(msg->any.head)) {
669 			n = read(iocom->sock_fd,
670 				 ioq->buf + ioq->fifo_end,
671 				 nmax);
672 			if (n <= 0) {
673 				if (n == 0) {
674 					ioq->error = DMSG_IOQ_ERROR_EOF;
675 					break;
676 				}
677 				if (errno != EINTR &&
678 				    errno != EINPROGRESS &&
679 				    errno != EAGAIN) {
680 					ioq->error = DMSG_IOQ_ERROR_SOCK;
681 					break;
682 				}
683 				n = 0;
684 				/* fall through */
685 			}
686 			ioq->fifo_end += (size_t)n;
687 			nmax -= (size_t)n;
688 		}
689 
690 		/*
691 		 * Decrypt data received so far.  Data will be decrypted
692 		 * in-place but might create gaps in the FIFO.  Partial
693 		 * blocks are not immediately decrypted.
694 		 *
695 		 * WARNING!  The header might be in the wrong endian, we
696 		 *	     do not fix it up until we get the entire
697 		 *	     extended header.
698 		 */
699 		if (iocom->flags & DMSG_IOCOMF_CRYPTED) {
700 			dmsg_crypto_decrypt(iocom, ioq);
701 		} else {
702 			ioq->fifo_cdx = ioq->fifo_end;
703 			ioq->fifo_cdn = ioq->fifo_end;
704 		}
705 		bytes = ioq->fifo_cdx - ioq->fifo_beg;
706 
707 		/*
708 		 * Insufficient data accumulated (msg is NULL, caller will
709 		 * retry on event).
710 		 */
711 		assert(msg == NULL);
712 		if (bytes < sizeof(msg->any.head))
713 			break;
714 
715 		/*
716 		 * Check and fixup the core header.  Note that the icrc
717 		 * has to be calculated before any fixups, but the crc
718 		 * fields in the msg may have to be swapped like everything
719 		 * else.
720 		 */
721 		head = (void *)(ioq->buf + ioq->fifo_beg);
722 		if (head->magic != DMSG_HDR_MAGIC &&
723 		    head->magic != DMSG_HDR_MAGIC_REV) {
724 			dmio_printf(iocom, 1,
725 				    "%s: head->magic is bad %02x\n",
726 				    iocom->label, head->magic);
727 			if (iocom->flags & DMSG_IOCOMF_CRYPTED)
728 				dmio_printf(iocom, 1, "%s\n",
729 					    "(on encrypted link)");
730 			ioq->error = DMSG_IOQ_ERROR_SYNC;
731 			break;
732 		}
733 
734 		/*
735 		 * Calculate the full header size and aux data size
736 		 */
737 		if (head->magic == DMSG_HDR_MAGIC_REV) {
738 			ioq->hbytes = (bswap32(head->cmd) & DMSGF_SIZE) *
739 				      DMSG_ALIGN;
740 			aux_size = bswap32(head->aux_bytes);
741 		} else {
742 			ioq->hbytes = (head->cmd & DMSGF_SIZE) *
743 				      DMSG_ALIGN;
744 			aux_size = head->aux_bytes;
745 		}
746 		ioq->abytes = DMSG_DOALIGN(aux_size);
747 		ioq->unaligned_aux_size = aux_size;
748 		if (ioq->hbytes < sizeof(msg->any.head) ||
749 		    ioq->hbytes > sizeof(msg->any) ||
750 		    ioq->abytes > DMSG_AUX_MAX) {
751 			ioq->error = DMSG_IOQ_ERROR_FIELD;
752 			break;
753 		}
754 
755 		/*
756 		 * Allocate the message, the next state will fill it in.
757 		 *
758 		 * NOTE: The aux_data buffer will be sized to an aligned
759 		 *	 value and the aligned remainder zero'd for
760 		 *	 convenience.
761 		 *
762 		 * NOTE: Supply dummy state and a degenerate cmd without
763 		 *	 CREATE set.  The message will temporarily be
764 		 *	 associated with state0 until later post-processing.
765 		 */
766 		msg = dmsg_msg_alloc(&iocom->state0, aux_size,
767 				     ioq->hbytes / DMSG_ALIGN,
768 				     NULL, NULL);
769 		ioq->msg = msg;
770 
771 		/*
772 		 * Fall through to the next state.  Make sure that the
773 		 * extended header does not straddle the end of the buffer.
774 		 * We still want to issue larger reads into our buffer,
775 		 * book-keeping is easier if we don't bcopy() yet.
776 		 *
777 		 * Make sure there is enough room for bloated encrypt data.
778 		 */
779 		nmax = dmsg_ioq_makeroom(ioq, ioq->hbytes);
780 		ioq->state = DMSG_MSGQ_STATE_HEADER2;
781 		/* fall through */
782 	case DMSG_MSGQ_STATE_HEADER2:
783 		/*
784 		 * Fill out the extended header.
785 		 */
786 		assert(msg != NULL);
787 		if (bytes < ioq->hbytes) {
788 			assert(nmax > 0);
789 			n = read(iocom->sock_fd,
790 				 ioq->buf + ioq->fifo_end,
791 				 nmax);
792 			if (n <= 0) {
793 				if (n == 0) {
794 					ioq->error = DMSG_IOQ_ERROR_EOF;
795 					break;
796 				}
797 				if (errno != EINTR &&
798 				    errno != EINPROGRESS &&
799 				    errno != EAGAIN) {
800 					ioq->error = DMSG_IOQ_ERROR_SOCK;
801 					break;
802 				}
803 				n = 0;
804 				/* fall through */
805 			}
806 			ioq->fifo_end += (size_t)n;
807 			nmax -= (size_t)n;
808 		}
809 
810 		if (iocom->flags & DMSG_IOCOMF_CRYPTED) {
811 			dmsg_crypto_decrypt(iocom, ioq);
812 		} else {
813 			ioq->fifo_cdx = ioq->fifo_end;
814 			ioq->fifo_cdn = ioq->fifo_end;
815 		}
816 		bytes = ioq->fifo_cdx - ioq->fifo_beg;
817 
818 		/*
819 		 * Insufficient data accumulated (set msg NULL so caller will
820 		 * retry on event).
821 		 */
822 		if (bytes < ioq->hbytes) {
823 			msg = NULL;
824 			break;
825 		}
826 
827 		/*
828 		 * Calculate the extended header, decrypt data received
829 		 * so far.  Handle endian-conversion for the entire extended
830 		 * header.
831 		 */
832 		head = (void *)(ioq->buf + ioq->fifo_beg);
833 
834 		/*
835 		 * Check the CRC.
836 		 */
837 		if (head->magic == DMSG_HDR_MAGIC_REV)
838 			xcrc32 = bswap32(head->hdr_crc);
839 		else
840 			xcrc32 = head->hdr_crc;
841 		head->hdr_crc = 0;
842 		if (dmsg_icrc32(head, ioq->hbytes) != xcrc32) {
843 			ioq->error = DMSG_IOQ_ERROR_XCRC;
844 			dmio_printf(iocom, 1, "BAD-XCRC(%08x,%08x) %s\n",
845 				    xcrc32, dmsg_icrc32(head, ioq->hbytes),
846 				    dmsg_msg_str(msg));
847 			assert(0);
848 			break;
849 		}
850 		head->hdr_crc = xcrc32;
851 
852 		if (head->magic == DMSG_HDR_MAGIC_REV) {
853 			dmsg_bswap_head(head);
854 		}
855 
856 		/*
857 		 * Copy the extended header into the msg and adjust the
858 		 * FIFO.
859 		 */
860 		bcopy(head, &msg->any, ioq->hbytes);
861 
862 		/*
863 		 * We are either done or we fall-through.
864 		 */
865 		if (ioq->abytes == 0) {
866 			ioq->fifo_beg += ioq->hbytes;
867 			break;
868 		}
869 
870 		/*
871 		 * Must adjust bytes (and the state) when falling through.
872 		 * nmax doesn't change.
873 		 */
874 		ioq->fifo_beg += ioq->hbytes;
875 		bytes -= ioq->hbytes;
876 		ioq->state = DMSG_MSGQ_STATE_AUXDATA1;
877 		/* fall through */
878 	case DMSG_MSGQ_STATE_AUXDATA1:
879 		/*
880 		 * Copy the partial or complete [decrypted] payload from
881 		 * remaining bytes in the FIFO in order to optimize the
882 		 * makeroom call in the AUXDATA2 state.  We have to
883 		 * fall-through either way so we can check the crc.
884 		 *
885 		 * msg->aux_size tracks our aux data.
886 		 *
887 		 * (Lets not complicate matters if the data is encrypted,
888 		 *  since the data in-stream is not the same size as the
889 		 *  data decrypted).
890 		 */
891 		if (bytes >= ioq->abytes) {
892 			bcopy(ioq->buf + ioq->fifo_beg, msg->aux_data,
893 			      ioq->abytes);
894 			msg->aux_size = ioq->abytes;
895 			ioq->fifo_beg += ioq->abytes;
896 			assert(ioq->fifo_beg <= ioq->fifo_cdx);
897 			assert(ioq->fifo_cdx <= ioq->fifo_cdn);
898 			bytes -= ioq->abytes;
899 		} else if (bytes) {
900 			bcopy(ioq->buf + ioq->fifo_beg, msg->aux_data,
901 			      bytes);
902 			msg->aux_size = bytes;
903 			ioq->fifo_beg += bytes;
904 			if (ioq->fifo_cdx < ioq->fifo_beg)
905 				ioq->fifo_cdx = ioq->fifo_beg;
906 			assert(ioq->fifo_beg <= ioq->fifo_cdx);
907 			assert(ioq->fifo_cdx <= ioq->fifo_cdn);
908 			bytes = 0;
909 		} else {
910 			msg->aux_size = 0;
911 		}
912 		ioq->state = DMSG_MSGQ_STATE_AUXDATA2;
913 		/* fall through */
914 	case DMSG_MSGQ_STATE_AUXDATA2:
915 		/*
916 		 * Make sure there is enough room for more data.
917 		 */
918 		assert(msg);
919 		nmax = dmsg_ioq_makeroom(ioq, ioq->abytes - msg->aux_size);
920 
921 		/*
922 		 * Read and decrypt more of the payload.
923 		 */
924 		if (msg->aux_size < ioq->abytes) {
925 			assert(nmax > 0);
926 			assert(bytes == 0);
927 			n = read(iocom->sock_fd,
928 				 ioq->buf + ioq->fifo_end,
929 				 nmax);
930 			if (n <= 0) {
931 				if (n == 0) {
932 					ioq->error = DMSG_IOQ_ERROR_EOF;
933 					break;
934 				}
935 				if (errno != EINTR &&
936 				    errno != EINPROGRESS &&
937 				    errno != EAGAIN) {
938 					ioq->error = DMSG_IOQ_ERROR_SOCK;
939 					break;
940 				}
941 				n = 0;
942 				/* fall through */
943 			}
944 			ioq->fifo_end += (size_t)n;
945 			nmax -= (size_t)n;
946 		}
947 
948 		if (iocom->flags & DMSG_IOCOMF_CRYPTED) {
949 			dmsg_crypto_decrypt(iocom, ioq);
950 		} else {
951 			ioq->fifo_cdx = ioq->fifo_end;
952 			ioq->fifo_cdn = ioq->fifo_end;
953 		}
954 		bytes = ioq->fifo_cdx - ioq->fifo_beg;
955 
956 		if (bytes > ioq->abytes - msg->aux_size)
957 			bytes = ioq->abytes - msg->aux_size;
958 
959 		if (bytes) {
960 			bcopy(ioq->buf + ioq->fifo_beg,
961 			      msg->aux_data + msg->aux_size,
962 			      bytes);
963 			msg->aux_size += bytes;
964 			ioq->fifo_beg += bytes;
965 		}
966 
967 		/*
968 		 * Insufficient data accumulated (set msg NULL so caller will
969 		 * retry on event).
970 		 *
971 		 * Assert the auxillary data size is correct, then record the
972 		 * original unaligned size from the message header.
973 		 */
974 		if (msg->aux_size < ioq->abytes) {
975 			msg = NULL;
976 			break;
977 		}
978 		assert(msg->aux_size == ioq->abytes);
979 		msg->aux_size = ioq->unaligned_aux_size;
980 
981 		/*
982 		 * Check aux_crc, then we are done.  Note that the crc
983 		 * is calculated over the aligned size, not the actual
984 		 * size.
985 		 */
986 		xcrc32 = dmsg_icrc32(msg->aux_data, ioq->abytes);
987 		if (xcrc32 != msg->any.head.aux_crc) {
988 			ioq->error = DMSG_IOQ_ERROR_ACRC;
989 			dmio_printf(iocom, 1,
990 				    "iocom: ACRC error %08x vs %08x "
991 				    "msgid %016jx msgcmd %08x auxsize %d\n",
992 				    xcrc32,
993 				    msg->any.head.aux_crc,
994 				    (intmax_t)msg->any.head.msgid,
995 				    msg->any.head.cmd,
996 				    msg->any.head.aux_bytes);
997 			break;
998 		}
999 		break;
1000 	case DMSG_MSGQ_STATE_ERROR:
1001 		/*
1002 		 * Continued calls to drain recorded transactions (returning
1003 		 * a LNK_ERROR for each one), before we return the final
1004 		 * LNK_ERROR.
1005 		 */
1006 		assert(msg == NULL);
1007 		break;
1008 	default:
1009 		/*
1010 		 * We don't double-return errors, the caller should not
1011 		 * have called us again after getting an error msg.
1012 		 */
1013 		assert(0);
1014 		break;
1015 	}
1016 
1017 	/*
1018 	 * Check the message sequence.  The iv[] should prevent any
1019 	 * possibility of a replay but we add this check anyway.
1020 	 */
1021 	if (msg && ioq->error == 0) {
1022 		if ((msg->any.head.salt & 255) != (ioq->seq & 255)) {
1023 			ioq->error = DMSG_IOQ_ERROR_MSGSEQ;
1024 		} else {
1025 			++ioq->seq;
1026 		}
1027 	}
1028 
1029 	/*
1030 	 * Handle error, RREQ, or completion
1031 	 *
1032 	 * NOTE: nmax and bytes are invalid at this point, we don't bother
1033 	 *	 to update them when breaking out.
1034 	 */
1035 	if (ioq->error) {
1036 skip:
1037 		/*
1038 		 * An unrecoverable error causes all active receive
1039 		 * transactions to be terminated with a LNK_ERROR message.
1040 		 *
1041 		 * Once all active transactions are exhausted we set the
1042 		 * iocom ERROR flag and return a non-transactional LNK_ERROR
1043 		 * message, which should cause master processing loops to
1044 		 * terminate.
1045 		 */
1046 		dmio_printf(iocom, 1, "IOQ ERROR %d\n", ioq->error);
1047 		assert(ioq->msg == msg);
1048 		if (msg) {
1049 			dmsg_msg_free(msg);
1050 			ioq->msg = NULL;
1051 			msg = NULL;
1052 		}
1053 
1054 		/*
1055 		 * No more I/O read processing
1056 		 */
1057 		ioq->state = DMSG_MSGQ_STATE_ERROR;
1058 
1059 		/*
1060 		 * Simulate a remote LNK_ERROR DELETE msg for any open
1061 		 * transactions, ending with a final non-transactional
1062 		 * LNK_ERROR (that the session can detect) when no
1063 		 * transactions remain.
1064 		 *
1065 		 * NOTE: Temporarily supply state0 and a degenerate cmd
1066 		 *	 without CREATE set.  The real state will be
1067 		 *	 assigned in the loop.
1068 		 *
1069 		 * NOTE: We are simulating a received message using our
1070 		 *	 side of the state, so the DMSGF_REV* bits have
1071 		 *	 to be reversed.
1072 		 */
1073 		pthread_mutex_lock(&iocom->mtx);
1074 		dmsg_iocom_drain(iocom);
1075 		dmsg_simulate_failure(&iocom->state0, 0, ioq->error);
1076 		pthread_mutex_unlock(&iocom->mtx);
1077 		if (TAILQ_FIRST(&ioq->msgq))
1078 			goto again;
1079 
1080 #if 0
1081 		/*
1082 		 * For the iocom error case we want to set RWORK to indicate
1083 		 * that more messages might be pending.
1084 		 *
1085 		 * It is possible to return NULL when there is more work to
1086 		 * do because each message has to be DELETEd in both
1087 		 * directions before we continue on with the next (though
1088 		 * this could be optimized).  The transmit direction will
1089 		 * re-set RWORK.
1090 		 */
1091 		if (msg)
1092 			atomic_set_int(&iocom->flags, DMSG_IOCOMF_RWORK);
1093 #endif
1094 	} else if (msg == NULL) {
1095 		/*
1096 		 * Insufficient data received to finish building the message,
1097 		 * set RREQ and return NULL.
1098 		 *
1099 		 * Leave ioq->msg intact.
1100 		 * Leave the FIFO intact.
1101 		 */
1102 		atomic_set_int(&iocom->flags, DMSG_IOCOMF_RREQ);
1103 	} else {
1104 		/*
1105 		 * Continue processing msg.
1106 		 *
1107 		 * The fifo has already been advanced past the message.
1108 		 * Trivially reset the FIFO indices if possible.
1109 		 *
1110 		 * clear the FIFO if it is now empty and set RREQ to wait
1111 		 * for more from the socket.  If the FIFO is not empty set
1112 		 * TWORK to bypass the poll so we loop immediately.
1113 		 */
1114 		if (ioq->fifo_beg == ioq->fifo_cdx &&
1115 		    ioq->fifo_cdn == ioq->fifo_end) {
1116 			atomic_set_int(&iocom->flags, DMSG_IOCOMF_RREQ);
1117 			ioq->fifo_cdx = 0;
1118 			ioq->fifo_cdn = 0;
1119 			ioq->fifo_beg = 0;
1120 			ioq->fifo_end = 0;
1121 		} else {
1122 			atomic_set_int(&iocom->flags, DMSG_IOCOMF_RWORK);
1123 		}
1124 		ioq->state = DMSG_MSGQ_STATE_HEADER1;
1125 		ioq->msg = NULL;
1126 
1127 		/*
1128 		 * Handle message routing.  Validates non-zero sources
1129 		 * and routes message.  Error will be 0 if the message is
1130 		 * destined for us.
1131 		 *
1132 		 * State processing only occurs for messages destined for us.
1133 		 */
1134 		dmio_printf(iocom, 5,
1135 			    "rxmsg cmd=%08x circ=%016jx\n",
1136 			    msg->any.head.cmd,
1137 			    (intmax_t)msg->any.head.circuit);
1138 
1139 		error = dmsg_state_msgrx(msg, 0);
1140 
1141 		if (error) {
1142 			/*
1143 			 * Abort-after-closure, throw message away and
1144 			 * start reading another.
1145 			 */
1146 			if (error == DMSG_IOQ_ERROR_EALREADY) {
1147 				dmsg_msg_free(msg);
1148 				goto again;
1149 			}
1150 
1151 			/*
1152 			 * Process real error and throw away message.
1153 			 */
1154 			ioq->error = error;
1155 			goto skip;
1156 		}
1157 
1158 		/*
1159 		 * No error and not routed
1160 		 */
1161 		/* no error, not routed.  Fall through and return msg */
1162 	}
1163 	return (msg);
1164 }
1165 
1166 /*
1167  * Calculate the header and data crc's and write a low-level message to
1168  * the connection.  If aux_crc is non-zero the aux_data crc is already
1169  * assumed to have been set.
1170  *
1171  * A non-NULL msg is added to the queue but not necessarily flushed.
1172  * Calling this function with msg == NULL will get a flush going.
1173  *
1174  * (called from iocom_core only)
1175  */
1176 void
1177 dmsg_iocom_flush1(dmsg_iocom_t *iocom)
1178 {
1179 	dmsg_ioq_t *ioq = &iocom->ioq_tx;
1180 	dmsg_msg_t *msg;
1181 	uint32_t xcrc32;
1182 	size_t hbytes;
1183 	size_t abytes;
1184 	dmsg_msg_queue_t tmpq;
1185 
1186 	atomic_clear_int(&iocom->flags, DMSG_IOCOMF_WREQ | DMSG_IOCOMF_WWORK);
1187 	TAILQ_INIT(&tmpq);
1188 	pthread_mutex_lock(&iocom->mtx);
1189 	while ((msg = TAILQ_FIRST(&iocom->txmsgq)) != NULL) {
1190 		TAILQ_REMOVE(&iocom->txmsgq, msg, qentry);
1191 		TAILQ_INSERT_TAIL(&tmpq, msg, qentry);
1192 	}
1193 	pthread_mutex_unlock(&iocom->mtx);
1194 
1195 	/*
1196 	 * Flush queue, doing all required encryption and CRC generation,
1197 	 * with the mutex unlocked.
1198 	 */
1199 	while ((msg = TAILQ_FIRST(&tmpq)) != NULL) {
1200 		/*
1201 		 * Process terminal connection errors.
1202 		 */
1203 		TAILQ_REMOVE(&tmpq, msg, qentry);
1204 		if (ioq->error) {
1205 			TAILQ_INSERT_TAIL(&ioq->msgq, msg, qentry);
1206 			++ioq->msgcount;
1207 			continue;
1208 		}
1209 
1210 		/*
1211 		 * Finish populating the msg fields.  The salt ensures that
1212 		 * the iv[] array is ridiculously randomized and we also
1213 		 * re-seed our PRNG every 32768 messages just to be sure.
1214 		 */
1215 		msg->any.head.magic = DMSG_HDR_MAGIC;
1216 		msg->any.head.salt = (random() << 8) | (ioq->seq & 255);
1217 		++ioq->seq;
1218 		if ((ioq->seq & 32767) == 0) {
1219 			pthread_mutex_lock(&iocom->mtx);
1220 			srandomdev();
1221 			pthread_mutex_unlock(&iocom->mtx);
1222 		}
1223 
1224 		/*
1225 		 * Calculate aux_crc if 0, then calculate hdr_crc.
1226 		 */
1227 		if (msg->aux_size && msg->any.head.aux_crc == 0) {
1228 			abytes = DMSG_DOALIGN(msg->aux_size);
1229 			xcrc32 = dmsg_icrc32(msg->aux_data, abytes);
1230 			msg->any.head.aux_crc = xcrc32;
1231 		}
1232 		msg->any.head.aux_bytes = msg->aux_size;
1233 
1234 		hbytes = (msg->any.head.cmd & DMSGF_SIZE) *
1235 			 DMSG_ALIGN;
1236 		msg->any.head.hdr_crc = 0;
1237 		msg->any.head.hdr_crc = dmsg_icrc32(&msg->any.head, hbytes);
1238 
1239 		/*
1240 		 * Enqueue the message (the flush codes handles stream
1241 		 * encryption).
1242 		 */
1243 		TAILQ_INSERT_TAIL(&ioq->msgq, msg, qentry);
1244 		++ioq->msgcount;
1245 	}
1246 	dmsg_iocom_flush2(iocom);
1247 }
1248 
1249 /*
1250  * Thread localized, iocom->mtx not held by caller.
1251  *
1252  * (called from iocom_core via iocom_flush1 only)
1253  */
1254 void
1255 dmsg_iocom_flush2(dmsg_iocom_t *iocom)
1256 {
1257 	dmsg_ioq_t *ioq = &iocom->ioq_tx;
1258 	dmsg_msg_t *msg;
1259 	ssize_t n;
1260 	struct iovec iov[DMSG_IOQ_MAXIOVEC];
1261 	size_t nact;
1262 	size_t hbytes;
1263 	size_t abytes;
1264 	size_t hoff;
1265 	size_t aoff;
1266 	int iovcnt;
1267 	int save_errno;
1268 
1269 	if (ioq->error) {
1270 		dmsg_iocom_drain(iocom);
1271 		return;
1272 	}
1273 
1274 	/*
1275 	 * Pump messages out the connection by building an iovec.
1276 	 *
1277 	 * ioq->hbytes/ioq->abytes tracks how much of the first message
1278 	 * in the queue has been successfully written out, so we can
1279 	 * resume writing.
1280 	 */
1281 	iovcnt = 0;
1282 	nact = 0;
1283 	hoff = ioq->hbytes;
1284 	aoff = ioq->abytes;
1285 
1286 	TAILQ_FOREACH(msg, &ioq->msgq, qentry) {
1287 		hbytes = (msg->any.head.cmd & DMSGF_SIZE) *
1288 			 DMSG_ALIGN;
1289 		abytes = DMSG_DOALIGN(msg->aux_size);
1290 		assert(hoff <= hbytes && aoff <= abytes);
1291 
1292 		if (hoff < hbytes) {
1293 			size_t maxlen = hbytes - hoff;
1294 			if (maxlen > sizeof(ioq->buf) / 2)
1295 				maxlen = sizeof(ioq->buf) / 2;
1296 			iov[iovcnt].iov_base = (char *)&msg->any.head + hoff;
1297 			iov[iovcnt].iov_len = maxlen;
1298 			nact += maxlen;
1299 			++iovcnt;
1300 			if (iovcnt == DMSG_IOQ_MAXIOVEC ||
1301 			    maxlen != hbytes - hoff) {
1302 				break;
1303 			}
1304 		}
1305 		if (aoff < abytes) {
1306 			size_t maxlen = abytes - aoff;
1307 			if (maxlen > sizeof(ioq->buf) / 2)
1308 				maxlen = sizeof(ioq->buf) / 2;
1309 
1310 			assert(msg->aux_data != NULL);
1311 			iov[iovcnt].iov_base = (char *)msg->aux_data + aoff;
1312 			iov[iovcnt].iov_len = maxlen;
1313 			nact += maxlen;
1314 			++iovcnt;
1315 			if (iovcnt == DMSG_IOQ_MAXIOVEC ||
1316 			    maxlen != abytes - aoff) {
1317 				break;
1318 			}
1319 		}
1320 		hoff = 0;
1321 		aoff = 0;
1322 	}
1323 
1324 	/*
1325 	 * Shortcut if no work to do.  Be sure to check for old work still
1326 	 * pending in the FIFO.
1327 	 */
1328 	if (iovcnt == 0 && ioq->fifo_beg == ioq->fifo_cdx)
1329 		return;
1330 
1331 	/*
1332 	 * Encrypt and write the data.  The crypto code will move the
1333 	 * data into the fifo and adjust the iov as necessary.  If
1334 	 * encryption is disabled the iov is left alone.
1335 	 *
1336 	 * May return a smaller iov (thus a smaller n), with aggregated
1337 	 * chunks.  May reduce nmax to what fits in the FIFO.
1338 	 *
1339 	 * This function sets nact to the number of original bytes now
1340 	 * encrypted, adding to the FIFO some number of bytes that might
1341 	 * be greater depending on the crypto mechanic.  iov[] is adjusted
1342 	 * to point at the FIFO if necessary.
1343 	 *
1344 	 * NOTE: nact is the number of bytes eaten from the message.  For
1345 	 *	 encrypted data this is the number of bytes processed for
1346 	 *	 encryption and not necessarily the number of bytes writable.
1347 	 *	 The return value from the writev() is the post-encrypted
1348 	 *	 byte count which might be larger.
1349 	 *
1350 	 * NOTE: For direct writes, nact is the return value from the writev().
1351 	 */
1352 	if (iocom->flags & DMSG_IOCOMF_CRYPTED) {
1353 		/*
1354 		 * Make sure the FIFO has a reasonable amount of space
1355 		 * left (if not completely full).
1356 		 *
1357 		 * In this situation we are staging the encrypted message
1358 		 * data in the FIFO.  (nact) represents how much plaintext
1359 		 * has been staged, (n) represents how much encrypted data
1360 		 * has been flushed.  The two are independent of each other.
1361 		 */
1362 		if (ioq->fifo_beg > sizeof(ioq->buf) / 2 &&
1363 		    sizeof(ioq->buf) - ioq->fifo_end < DMSG_ALIGN * 2) {
1364 			bcopy(ioq->buf + ioq->fifo_beg, ioq->buf,
1365 			      ioq->fifo_end - ioq->fifo_beg);
1366 			ioq->fifo_cdx -= ioq->fifo_beg;
1367 			ioq->fifo_cdn -= ioq->fifo_beg;
1368 			ioq->fifo_end -= ioq->fifo_beg;
1369 			ioq->fifo_beg = 0;
1370 		}
1371 
1372 		/*
1373 		 * beg .... cdx ............ cdn ............. end
1374 		 * [WRITABLE] [PARTIALENCRYPT] [NOTYETENCRYPTED]
1375 		 *
1376 		 * Advance fifo_beg on a successful write.
1377 		 */
1378 		iovcnt = dmsg_crypto_encrypt(iocom, ioq, iov, iovcnt, &nact);
1379 		n = writev(iocom->sock_fd, iov, iovcnt);
1380 		save_errno = errno;
1381 		if (n > 0) {
1382 			ioq->fifo_beg += n;
1383 			if (ioq->fifo_beg == ioq->fifo_end) {
1384 				ioq->fifo_beg = 0;
1385 				ioq->fifo_cdn = 0;
1386 				ioq->fifo_cdx = 0;
1387 				ioq->fifo_end = 0;
1388 			}
1389 		}
1390 
1391 		/*
1392 		 * We don't mess with the nact returned by the crypto_encrypt
1393 		 * call, which represents the filling of the FIFO.  (n) tells
1394 		 * us how much we were able to write from the FIFO.  The two
1395 		 * are different beasts when encrypting.
1396 		 */
1397 	} else {
1398 		/*
1399 		 * In this situation we are not staging the messages to the
1400 		 * FIFO but instead writing them directly from the msg
1401 		 * structure(s) unencrypted, so (nact) is basically (n).
1402 		 */
1403 		n = writev(iocom->sock_fd, iov, iovcnt);
1404 		save_errno = errno;
1405 		if (n > 0)
1406 			nact = n;
1407 		else
1408 			nact = 0;
1409 	}
1410 
1411 	/*
1412 	 * Clean out the transmit queue based on what we successfully
1413 	 * encrypted (nact is the plaintext count) and is now in the FIFO.
1414 	 * ioq->hbytes/abytes represents the portion of the first message
1415 	 * previously sent.
1416 	 */
1417 	while ((msg = TAILQ_FIRST(&ioq->msgq)) != NULL) {
1418 		hbytes = (msg->any.head.cmd & DMSGF_SIZE) *
1419 			 DMSG_ALIGN;
1420 		abytes = DMSG_DOALIGN(msg->aux_size);
1421 
1422 		if ((size_t)nact < hbytes - ioq->hbytes) {
1423 			ioq->hbytes += nact;
1424 			nact = 0;
1425 			break;
1426 		}
1427 		nact -= hbytes - ioq->hbytes;
1428 		ioq->hbytes = hbytes;
1429 		if ((size_t)nact < abytes - ioq->abytes) {
1430 			ioq->abytes += nact;
1431 			nact = 0;
1432 			break;
1433 		}
1434 		nact -= abytes - ioq->abytes;
1435 		/* ioq->abytes = abytes; optimized out */
1436 
1437 		dmio_printf(iocom, 5,
1438 			    "txmsg cmd=%08x circ=%016jx\n",
1439 			    msg->any.head.cmd,
1440 			    (intmax_t)msg->any.head.circuit);
1441 
1442 #ifdef DMSG_BLOCK_DEBUG
1443 		uint32_t tcmd;
1444 
1445 		if (msg->any.head.cmd & (DMSGF_CREATE | DMSGF_DELETE)) {
1446 			if ((msg->state->flags & DMSG_STATE_ROOT) == 0) {
1447 				tcmd = (msg->state->icmd & DMSGF_BASECMDMASK) |
1448 					    (msg->any.head.cmd & (DMSGF_CREATE |
1449 								  DMSGF_DELETE |
1450 								  DMSGF_REPLY));
1451 			} else {
1452 				tcmd = 0;
1453 			}
1454 		} else {
1455 			tcmd = msg->any.head.cmd & DMSGF_CMDSWMASK;
1456 		}
1457 
1458 		switch (tcmd) {
1459 		case DMSG_BLK_READ | DMSGF_CREATE | DMSGF_DELETE:
1460 		case DMSG_BLK_WRITE | DMSGF_CREATE | DMSGF_DELETE:
1461 			dmio_printf(iocom, 4,
1462 				    "write BIO %-3d %016jx %d@%016jx\n",
1463 				    biocount, msg->any.head.msgid,
1464 				    msg->any.blk_read.bytes,
1465 				    msg->any.blk_read.offset);
1466 			break;
1467 		case DMSG_BLK_READ | DMSGF_CREATE | DMSGF_DELETE | DMSGF_REPLY:
1468 		case DMSG_BLK_WRITE | DMSGF_CREATE | DMSGF_DELETE | DMSGF_REPLY:
1469 			dmio_printf(iocom, 4,
1470 				    "wretr BIO %-3d %016jx %d@%016jx\n",
1471 				    biocount, msg->any.head.msgid,
1472 				    msg->any.blk_read.bytes,
1473 				    msg->any.blk_read.offset);
1474 			break;
1475 		default:
1476 			break;
1477 		}
1478 #endif
1479 
1480 		TAILQ_REMOVE(&ioq->msgq, msg, qentry);
1481 		--ioq->msgcount;
1482 		ioq->hbytes = 0;
1483 		ioq->abytes = 0;
1484 		dmsg_msg_free(msg);
1485 	}
1486 	assert(nact == 0);
1487 
1488 	/*
1489 	 * Process the return value from the write w/regards to blocking.
1490 	 */
1491 	if (n < 0) {
1492 		if (save_errno != EINTR &&
1493 		    save_errno != EINPROGRESS &&
1494 		    save_errno != EAGAIN) {
1495 			/*
1496 			 * Fatal write error
1497 			 */
1498 			ioq->error = DMSG_IOQ_ERROR_SOCK;
1499 			dmsg_iocom_drain(iocom);
1500 		} else {
1501 			/*
1502 			 * Wait for socket buffer space, do not try to
1503 			 * process more packets for transmit until space
1504 			 * is available.
1505 			 */
1506 			atomic_set_int(&iocom->flags, DMSG_IOCOMF_WREQ);
1507 		}
1508 	} else if (TAILQ_FIRST(&ioq->msgq) ||
1509 		   TAILQ_FIRST(&iocom->txmsgq) ||
1510 		   ioq->fifo_beg != ioq->fifo_cdx) {
1511 		/*
1512 		 * If the write succeeded and more messages are pending
1513 		 * in either msgq, or the FIFO WWORK must remain set.
1514 		 */
1515 		atomic_set_int(&iocom->flags, DMSG_IOCOMF_WWORK);
1516 	}
1517 	/* else no transmit-side work remains */
1518 
1519 	if (ioq->error) {
1520 		dmsg_iocom_drain(iocom);
1521 	}
1522 }
1523 
1524 /*
1525  * Kill pending msgs on ioq_tx and adjust the flags such that no more
1526  * write events will occur.  We don't kill read msgs because we want
1527  * the caller to pull off our contrived terminal error msg to detect
1528  * the connection failure.
1529  *
1530  * Localized to iocom_core thread, iocom->mtx not held by caller.
1531  */
1532 void
1533 dmsg_iocom_drain(dmsg_iocom_t *iocom)
1534 {
1535 	dmsg_ioq_t *ioq = &iocom->ioq_tx;
1536 	dmsg_msg_t *msg;
1537 
1538 	atomic_clear_int(&iocom->flags, DMSG_IOCOMF_WREQ | DMSG_IOCOMF_WWORK);
1539 	ioq->hbytes = 0;
1540 	ioq->abytes = 0;
1541 
1542 	while ((msg = TAILQ_FIRST(&ioq->msgq)) != NULL) {
1543 		TAILQ_REMOVE(&ioq->msgq, msg, qentry);
1544 		--ioq->msgcount;
1545 		dmsg_msg_free(msg);
1546 	}
1547 }
1548 
1549 /*
1550  * Write a message to an iocom, with additional state processing.
1551  */
1552 void
1553 dmsg_msg_write(dmsg_msg_t *msg)
1554 {
1555 	dmsg_iocom_t *iocom = msg->state->iocom;
1556 	dmsg_state_t *state;
1557 	char dummy;
1558 
1559 	pthread_mutex_lock(&iocom->mtx);
1560 	state = msg->state;
1561 
1562 	dmio_printf(iocom, 5,
1563 		    "msgtx: cmd=%08x msgid=%016jx "
1564 		    "state %p(%08x) error=%d\n",
1565 		    msg->any.head.cmd, msg->any.head.msgid,
1566 		    state, (state ? state->icmd : 0),
1567 		    msg->any.head.error);
1568 
1569 
1570 #if 0
1571 	/*
1572 	 * Make sure the parent transaction is still open in the transmit
1573 	 * direction.  If it isn't the message is dead and we have to
1574 	 * potentially simulate a rxmsg terminating the transaction.
1575 	 */
1576 	if ((state->parent->txcmd & DMSGF_DELETE) ||
1577 	    (state->parent->rxcmd & DMSGF_DELETE)) {
1578 		dmio_printf(iocom, 4, "dmsg_msg_write: EARLY TERMINATION\n");
1579 		dmsg_simulate_failure(state, DMSG_ERR_LOSTLINK);
1580 		dmsg_state_cleanuptx(iocom, msg);
1581 		dmsg_msg_free(msg);
1582 		pthread_mutex_unlock(&iocom->mtx);
1583 		return;
1584 	}
1585 #endif
1586 	/*
1587 	 * Process state data into the message as needed, then update the
1588 	 * state based on the message.
1589 	 */
1590 	if ((state->flags & DMSG_STATE_ROOT) == 0) {
1591 		/*
1592 		 * Existing transaction (could be reply).  It is also
1593 		 * possible for this to be the first reply (CREATE is set),
1594 		 * in which case we populate state->txcmd.
1595 		 *
1596 		 * state->txcmd is adjusted to hold the final message cmd,
1597 		 * and we also be sure to set the CREATE bit here.  We did
1598 		 * not set it in dmsg_msg_alloc() because that would have
1599 		 * not been serialized (state could have gotten ripped out
1600 		 * from under the message prior to it being transmitted).
1601 		 */
1602 		if ((msg->any.head.cmd & (DMSGF_CREATE | DMSGF_REPLY)) ==
1603 		    DMSGF_CREATE) {
1604 			state->txcmd = msg->any.head.cmd & ~DMSGF_DELETE;
1605 			state->icmd = state->txcmd & DMSGF_BASECMDMASK;
1606 			state->flags &= ~DMSG_STATE_NEW;
1607 		}
1608 		msg->any.head.msgid = state->msgid;
1609 
1610 		if (msg->any.head.cmd & DMSGF_CREATE) {
1611 			state->txcmd = msg->any.head.cmd & ~DMSGF_DELETE;
1612 		}
1613 	}
1614 
1615 	/*
1616 	 * Discard messages sent to transactions which are already dead.
1617 	 */
1618 	if (state && (state->txcmd & DMSGF_DELETE)) {
1619 		dmio_printf(iocom, 4,
1620 			    "dmsg_msg_write: drop msg %08x to dead "
1621 			    "circuit state=%p\n",
1622 			    msg->any.head.cmd, state);
1623 		dmsg_msg_free(msg);
1624 		return;
1625 	}
1626 
1627 	/*
1628 	 * Normally we queue the msg for output.  However, if the circuit is
1629 	 * dead or dying we must simulate a failure in the return direction
1630 	 * and throw the message away.  The other end is not expecting any
1631 	 * further messages from us on this state.
1632 	 *
1633 	 * Note that the I/O thread is responsible for generating the CRCs
1634 	 * and encryption.
1635 	 */
1636 	if (state->flags & DMSG_STATE_DYING) {
1637 #if 0
1638 	if ((state->parent->txcmd & DMSGF_DELETE) ||
1639 	    (state->parent->flags & DMSG_STATE_DYING) ||
1640 	    (state->flags & DMSG_STATE_DYING)) {
1641 #endif
1642 		/*
1643 		 * Illegal message, kill state and related sub-state.
1644 		 * Cannot transmit if state is already dying.
1645 		 */
1646 		dmio_printf(iocom, 4,
1647 			    "dmsg_msg_write: Write to dying circuit "
1648 			    "ptxcmd=%08x prxcmd=%08x flags=%08x\n",
1649 			    state->parent->rxcmd,
1650 			    state->parent->txcmd,
1651 			    state->parent->flags);
1652 		dmsg_state_hold(state);
1653 		dmsg_state_cleanuptx(iocom, msg);
1654 		if ((state->flags & DMSG_STATE_ABORTING) == 0) {
1655 			dmsg_simulate_failure(state, 1, DMSG_ERR_LOSTLINK);
1656 		}
1657 		dmsg_state_drop(state);
1658 		dmsg_msg_free(msg);
1659 	} else {
1660 		/*
1661 		 * Queue the message, clean up transmit state prior to queueing
1662 		 * to avoid SMP races.
1663 		 */
1664 		dmio_printf(iocom, 5,
1665 			    "dmsg_msg_write: commit msg state=%p to txkmsgq\n",
1666 			    state);
1667 		dmsg_state_cleanuptx(iocom, msg);
1668 		TAILQ_INSERT_TAIL(&iocom->txmsgq, msg, qentry);
1669 		dummy = 0;
1670 		write(iocom->wakeupfds[1], &dummy, 1);	/* XXX optimize me */
1671 	}
1672 	pthread_mutex_unlock(&iocom->mtx);
1673 }
1674 
1675 /*
1676  * Remove state from its parent's subq.  This can wind up recursively
1677  * dropping the parent upward.
1678  *
1679  * NOTE: iocom must be locked.
1680  *
1681  * NOTE: Once we drop the parent, our pstate pointer may become invalid.
1682  */
1683 static
1684 void
1685 dmsg_subq_delete(dmsg_state_t *state)
1686 {
1687 	dmsg_state_t *pstate;
1688 
1689 	if (state->flags & DMSG_STATE_SUBINSERTED) {
1690 		pstate = state->parent;
1691 		assert(pstate);
1692 		if (pstate->scan == state)
1693 			pstate->scan = NULL;
1694 		TAILQ_REMOVE(&pstate->subq, state, entry);
1695 		state->flags &= ~DMSG_STATE_SUBINSERTED;
1696 		state->parent = NULL;
1697 		if (TAILQ_EMPTY(&pstate->subq))
1698 			dmsg_state_drop(pstate);/* pstate->subq */
1699 		pstate = NULL;			/* safety */
1700 		dmsg_state_drop(state);         /* pstate->subq */
1701 	} else {
1702 		assert(state->parent == NULL);
1703 	}
1704 }
1705 
1706 /*
1707  * Simulate reception of a transaction DELETE message when the link goes
1708  * bad.  This routine must recurse through state->subq and generate messages
1709  * and callbacks bottom-up.
1710  *
1711  * iocom->mtx must be held by caller.
1712  */
1713 static
1714 void
1715 dmsg_simulate_failure(dmsg_state_t *state, int meto, int error)
1716 {
1717 	dmsg_state_t *substate;
1718 
1719 	dmsg_state_hold(state);
1720 	if (meto)
1721 		dmsg_state_abort(state);
1722 
1723 	/*
1724 	 * Recurse through sub-states.
1725 	 */
1726 again:
1727 	TAILQ_FOREACH(substate, &state->subq, entry) {
1728 		if (substate->flags & DMSG_STATE_ABORTING)
1729 			continue;
1730 		state->scan = substate;
1731 		dmsg_simulate_failure(substate, 1, error);
1732 		if (state->scan != substate)
1733 			goto again;
1734 	}
1735 
1736 	dmsg_state_drop(state);
1737 }
1738 
1739 static
1740 void
1741 dmsg_state_abort(dmsg_state_t *state)
1742 {
1743 	dmsg_iocom_t *iocom;
1744 	dmsg_msg_t *msg;
1745 
1746 	/*
1747 	 * Set ABORTING and DYING, return if already set.  If the state was
1748 	 * just allocated we defer the abort operation until the related
1749 	 * message is processed.
1750 	 */
1751 	if (state->flags & DMSG_STATE_ABORTING)
1752 		return;
1753 	state->flags |= DMSG_STATE_ABORTING;
1754 	dmsg_state_dying(state);
1755 	if (state->flags & DMSG_STATE_NEW) {
1756 		dmio_printf(iocom, 4,
1757 			    "dmsg_state_abort(0): state %p rxcmd %08x "
1758 			    "txcmd %08x flags %08x - in NEW state\n",
1759 			    state, state->rxcmd,
1760 			    state->txcmd, state->flags);
1761 		return;
1762 	}
1763 
1764 	/*
1765 	 * Simulate parent state failure before child states.  Device
1766 	 * drivers need to understand this and flag the situation but might
1767 	 * have asynchronous operations in progress that they cannot stop.
1768 	 * To make things easier, parent states will not actually disappear
1769 	 * until the children are all gone.
1770 	 */
1771 	if ((state->rxcmd & DMSGF_DELETE) == 0) {
1772 		dmio_printf(iocom, 5,
1773 			    "dmsg_state_abort() on state %p\n",
1774 			    state);
1775 		msg = dmsg_msg_alloc_locked(state, 0, DMSG_LNK_ERROR,
1776 					    NULL, NULL);
1777 		if ((state->rxcmd & DMSGF_CREATE) == 0)
1778 			msg->any.head.cmd |= DMSGF_CREATE;
1779 		msg->any.head.cmd |= DMSGF_DELETE |
1780 				     (state->rxcmd & DMSGF_REPLY);
1781 		msg->any.head.cmd ^= (DMSGF_REVTRANS | DMSGF_REVCIRC);
1782 		msg->any.head.error = DMSG_ERR_LOSTLINK;
1783 		msg->any.head.cmd |= DMSGF_ABORT;
1784 
1785 		/*
1786 		 * Issue callback synchronously even though this isn't
1787 		 * the receiver thread.  We need to issue the callback
1788 		 * before removing state from the subq in order to allow
1789 		 * the callback to reply.
1790 		 */
1791 		iocom = state->iocom;
1792 		dmsg_state_msgrx(msg, 1);
1793 		pthread_mutex_unlock(&iocom->mtx);
1794 		iocom->rcvmsg_callback(msg);
1795 		pthread_mutex_lock(&iocom->mtx);
1796 		dmsg_state_cleanuprx(iocom, msg);
1797 #if 0
1798 		TAILQ_INSERT_TAIL(&iocom->ioq_rx.msgq, msg, qentry);
1799 		atomic_set_int(&iocom->flags, DMSG_IOCOMF_RWORK);
1800 #endif
1801 	}
1802 }
1803 
1804 
1805 /*
1806  * Recursively sets DMSG_STATE_DYING on state and all sub-states, preventing
1807  * the transmission of any new messages on these states.  This is done
1808  * atomically when parent state is terminating, whereas setting ABORTING is
1809  * not atomic and can leak races.
1810  */
1811 static
1812 void
1813 dmsg_state_dying(dmsg_state_t *state)
1814 {
1815 	dmsg_state_t *scan;
1816 
1817 	if ((state->flags & DMSG_STATE_DYING) == 0) {
1818 		state->flags |= DMSG_STATE_DYING;
1819 		TAILQ_FOREACH(scan, &state->subq, entry)
1820 			dmsg_state_dying(scan);
1821 	}
1822 }
1823 
1824 /*
1825  * This is a shortcut to formulate a reply to msg with a simple error code,
1826  * It can reply to and terminate a transaction, or it can reply to a one-way
1827  * messages.  A DMSG_LNK_ERROR command code is utilized to encode
1828  * the error code (which can be 0).  Not all transactions are terminated
1829  * with DMSG_LNK_ERROR status (the low level only cares about the
1830  * MSGF_DELETE flag), but most are.
1831  *
1832  * Replies to one-way messages are a bit of an oxymoron but the feature
1833  * is used by the debug (DBG) protocol.
1834  *
1835  * The reply contains no extended data.
1836  */
1837 void
1838 dmsg_msg_reply(dmsg_msg_t *msg, uint32_t error)
1839 {
1840 	dmsg_state_t *state = msg->state;
1841 	dmsg_msg_t *nmsg;
1842 	uint32_t cmd;
1843 
1844 	/*
1845 	 * Reply with a simple error code and terminate the transaction.
1846 	 */
1847 	cmd = DMSG_LNK_ERROR;
1848 
1849 	/*
1850 	 * Check if our direction has even been initiated yet, set CREATE.
1851 	 *
1852 	 * Check what direction this is (command or reply direction).  Note
1853 	 * that txcmd might not have been initiated yet.
1854 	 *
1855 	 * If our direction has already been closed we just return without
1856 	 * doing anything.
1857 	 */
1858 	if ((state->flags & DMSG_STATE_ROOT) == 0) {
1859 		if (state->txcmd & DMSGF_DELETE)
1860 			return;
1861 		if (state->txcmd & DMSGF_REPLY)
1862 			cmd |= DMSGF_REPLY;
1863 		cmd |= DMSGF_DELETE;
1864 	} else {
1865 		if ((msg->any.head.cmd & DMSGF_REPLY) == 0)
1866 			cmd |= DMSGF_REPLY;
1867 	}
1868 
1869 	/*
1870 	 * Allocate the message and associate it with the existing state.
1871 	 * We cannot pass DMSGF_CREATE to msg_alloc() because that may
1872 	 * allocate new state.  We have our state already.
1873 	 */
1874 	nmsg = dmsg_msg_alloc(state, 0, cmd, NULL, NULL);
1875 	if ((state->flags & DMSG_STATE_ROOT) == 0) {
1876 		if ((state->txcmd & DMSGF_CREATE) == 0)
1877 			nmsg->any.head.cmd |= DMSGF_CREATE;
1878 	}
1879 	nmsg->any.head.error = error;
1880 
1881 	dmsg_msg_write(nmsg);
1882 }
1883 
1884 /*
1885  * Similar to dmsg_msg_reply() but leave the transaction open.  That is,
1886  * we are generating a streaming reply or an intermediate acknowledgement
1887  * of some sort as part of the higher level protocol, with more to come
1888  * later.
1889  */
1890 void
1891 dmsg_msg_result(dmsg_msg_t *msg, uint32_t error)
1892 {
1893 	dmsg_state_t *state = msg->state;
1894 	dmsg_msg_t *nmsg;
1895 	uint32_t cmd;
1896 
1897 
1898 	/*
1899 	 * Reply with a simple error code and terminate the transaction.
1900 	 */
1901 	cmd = DMSG_LNK_ERROR;
1902 
1903 	/*
1904 	 * Check if our direction has even been initiated yet, set CREATE.
1905 	 *
1906 	 * Check what direction this is (command or reply direction).  Note
1907 	 * that txcmd might not have been initiated yet.
1908 	 *
1909 	 * If our direction has already been closed we just return without
1910 	 * doing anything.
1911 	 */
1912 	if ((state->flags & DMSG_STATE_ROOT) == 0) {
1913 		if (state->txcmd & DMSGF_DELETE)
1914 			return;
1915 		if (state->txcmd & DMSGF_REPLY)
1916 			cmd |= DMSGF_REPLY;
1917 		/* continuing transaction, do not set MSGF_DELETE */
1918 	} else {
1919 		if ((msg->any.head.cmd & DMSGF_REPLY) == 0)
1920 			cmd |= DMSGF_REPLY;
1921 	}
1922 	nmsg = dmsg_msg_alloc(state, 0, cmd, NULL, NULL);
1923 	if ((state->flags & DMSG_STATE_ROOT) == 0) {
1924 		if ((state->txcmd & DMSGF_CREATE) == 0)
1925 			nmsg->any.head.cmd |= DMSGF_CREATE;
1926 	}
1927 	nmsg->any.head.error = error;
1928 
1929 	dmsg_msg_write(nmsg);
1930 }
1931 
1932 /*
1933  * Terminate a transaction given a state structure by issuing a DELETE.
1934  * (the state structure must not be &iocom->state0)
1935  */
1936 void
1937 dmsg_state_reply(dmsg_state_t *state, uint32_t error)
1938 {
1939 	dmsg_msg_t *nmsg;
1940 	uint32_t cmd = DMSG_LNK_ERROR | DMSGF_DELETE;
1941 
1942 	/*
1943 	 * Nothing to do if we already transmitted a delete
1944 	 */
1945 	if (state->txcmd & DMSGF_DELETE)
1946 		return;
1947 
1948 	/*
1949 	 * Set REPLY if the other end initiated the command.  Otherwise
1950 	 * we are the command direction.
1951 	 */
1952 	if (state->txcmd & DMSGF_REPLY)
1953 		cmd |= DMSGF_REPLY;
1954 
1955 	nmsg = dmsg_msg_alloc(state, 0, cmd, NULL, NULL);
1956 	if ((state->flags & DMSG_STATE_ROOT) == 0) {
1957 		if ((state->txcmd & DMSGF_CREATE) == 0)
1958 			nmsg->any.head.cmd |= DMSGF_CREATE;
1959 	}
1960 	nmsg->any.head.error = error;
1961 	dmsg_msg_write(nmsg);
1962 }
1963 
1964 /*
1965  * Terminate a transaction given a state structure by issuing a DELETE.
1966  * (the state structure must not be &iocom->state0)
1967  */
1968 void
1969 dmsg_state_result(dmsg_state_t *state, uint32_t error)
1970 {
1971 	dmsg_msg_t *nmsg;
1972 	uint32_t cmd = DMSG_LNK_ERROR;
1973 
1974 	/*
1975 	 * Nothing to do if we already transmitted a delete
1976 	 */
1977 	if (state->txcmd & DMSGF_DELETE)
1978 		return;
1979 
1980 	/*
1981 	 * Set REPLY if the other end initiated the command.  Otherwise
1982 	 * we are the command direction.
1983 	 */
1984 	if (state->txcmd & DMSGF_REPLY)
1985 		cmd |= DMSGF_REPLY;
1986 
1987 	nmsg = dmsg_msg_alloc(state, 0, cmd, NULL, NULL);
1988 	if ((state->flags & DMSG_STATE_ROOT) == 0) {
1989 		if ((state->txcmd & DMSGF_CREATE) == 0)
1990 			nmsg->any.head.cmd |= DMSGF_CREATE;
1991 	}
1992 	nmsg->any.head.error = error;
1993 	dmsg_msg_write(nmsg);
1994 }
1995 
1996 /************************************************************************
1997  *			TRANSACTION STATE HANDLING			*
1998  ************************************************************************
1999  *
2000  */
2001 
2002 /*
2003  * Process state tracking for a message after reception, prior to execution.
2004  * Possibly route the message (consuming it).
2005  *
2006  * Called with msglk held and the msg dequeued.
2007  *
2008  * All messages are called with dummy state and return actual state.
2009  * (One-off messages often just return the same dummy state).
2010  *
2011  * May request that caller discard the message by setting *discardp to 1.
2012  * The returned state is not used in this case and is allowed to be NULL.
2013  *
2014  * --
2015  *
2016  * These routines handle persistent and command/reply message state via the
2017  * CREATE and DELETE flags.  The first message in a command or reply sequence
2018  * sets CREATE, the last message in a command or reply sequence sets DELETE.
2019  *
2020  * There can be any number of intermediate messages belonging to the same
2021  * sequence sent inbetween the CREATE message and the DELETE message,
2022  * which set neither flag.  This represents a streaming command or reply.
2023  *
2024  * Any command message received with CREATE set expects a reply sequence to
2025  * be returned.  Reply sequences work the same as command sequences except the
2026  * REPLY bit is also sent.  Both the command side and reply side can
2027  * degenerate into a single message with both CREATE and DELETE set.  Note
2028  * that one side can be streaming and the other side not, or neither, or both.
2029  *
2030  * The msgid is unique for the initiator.  That is, two sides sending a new
2031  * message can use the same msgid without colliding.
2032  *
2033  * --
2034  *
2035  * The message may be running over a circuit.  If the circuit is half-deleted
2036  * The message is typically racing against a link failure and must be thrown
2037  * out.  As the circuit deletion propagates the library will automatically
2038  * generate terminations for sub states.
2039  *
2040  * --
2041  *
2042  * ABORT sequences work by setting the ABORT flag along with normal message
2043  * state.  However, ABORTs can also be sent on half-closed messages, that is
2044  * even if the command or reply side has already sent a DELETE, as long as
2045  * the message has not been fully closed it can still send an ABORT+DELETE
2046  * to terminate the half-closed message state.
2047  *
2048  * Since ABORT+DELETEs can race we silently discard ABORT's for message
2049  * state which has already been fully closed.  REPLY+ABORT+DELETEs can
2050  * also race, and in this situation the other side might have already
2051  * initiated a new unrelated command with the same message id.  Since
2052  * the abort has not set the CREATE flag the situation can be detected
2053  * and the message will also be discarded.
2054  *
2055  * Non-blocking requests can be initiated with ABORT+CREATE[+DELETE].
2056  * The ABORT request is essentially integrated into the command instead
2057  * of being sent later on.  In this situation the command implementation
2058  * detects that CREATE and ABORT are both set (vs ABORT alone) and can
2059  * special-case non-blocking operation for the command.
2060  *
2061  * NOTE!  Messages with ABORT set without CREATE or DELETE are considered
2062  *	  to be mid-stream aborts for command/reply sequences.  ABORTs on
2063  *	  one-way messages are not supported.
2064  *
2065  * NOTE!  If a command sequence does not support aborts the ABORT flag is
2066  *	  simply ignored.
2067  *
2068  * --
2069  *
2070  * One-off messages (no reply expected) are sent without an established
2071  * transaction.  CREATE and DELETE are left clear and the msgid is usually 0.
2072  * For one-off messages sent over circuits msgid generally MUST be 0.
2073  *
2074  * One-off messages cannot be aborted and typically aren't processed
2075  * by these routines.  Order is still guaranteed for messages sent over
2076  * the same circuit.  The REPLY bit can be used to distinguish whether
2077  * a one-off message is a command or reply.  For example, one-off replies
2078  * will typically just contain status updates.
2079  */
2080 static int
2081 dmsg_state_msgrx(dmsg_msg_t *msg, int mstate)
2082 {
2083 	dmsg_iocom_t *iocom = msg->state->iocom;
2084 	dmsg_state_t *state;
2085 	dmsg_state_t *pstate;
2086 	dmsg_state_t sdummy;
2087 	int error;
2088 
2089 	pthread_mutex_lock(&iocom->mtx);
2090 
2091 	if (DMsgDebugOpt) {
2092 		dmio_printf(iocom, 5,
2093 			    "msgrx: cmd=%08x msgid=%016jx "
2094 			    "circuit=%016jx error=%d\n",
2095 			    msg->any.head.cmd,
2096 			    msg->any.head.msgid,
2097 			    msg->any.head.circuit,
2098 			    msg->any.head.error);
2099 	}
2100 
2101 	/*
2102 	 * Lookup the circuit (pstate).  The circuit will be an open
2103 	 * transaction.  The REVCIRC bit in the message tells us which side
2104 	 * initiated it.
2105 	 *
2106 	 * If mstate is non-zero the state has already been incorporated
2107 	 * into the message as part of a simulated abort.  Note that in this
2108 	 * situation the parent state may have already been removed from
2109 	 * the RBTREE.
2110 	 */
2111 	if (mstate) {
2112 		pstate = msg->state->parent;
2113 	} else if (msg->any.head.circuit) {
2114 		sdummy.msgid = msg->any.head.circuit;
2115 
2116 		if (msg->any.head.cmd & DMSGF_REVCIRC) {
2117 			pstate = RB_FIND(dmsg_state_tree,
2118 					 &iocom->statewr_tree,
2119 					 &sdummy);
2120 		} else {
2121 			pstate = RB_FIND(dmsg_state_tree,
2122 					 &iocom->staterd_tree,
2123 					 &sdummy);
2124 		}
2125 
2126 		/*
2127 		 * If we cannot find the circuit throw the message away.
2128 		 * The state will have already been taken care of by
2129 		 * the simulated failure code.  This case can occur due
2130 		 * to a failure propagating in one direction crossing a
2131 		 * request on the failed circuit propagating in the other
2132 		 * direction.
2133 		 */
2134 		if (pstate == NULL) {
2135 			dmio_printf(iocom, 4,
2136 				    "missing parent in stacked trans %s\n",
2137 				    dmsg_msg_str(msg));
2138 			pthread_mutex_unlock(&iocom->mtx);
2139 			error = DMSG_IOQ_ERROR_EALREADY;
2140 
2141 			return error;
2142 		}
2143 	} else {
2144 		pstate = &iocom->state0;
2145 	}
2146 	/* WARNING: pstate not (yet) refd */
2147 
2148 	/*
2149 	 * Lookup the msgid.
2150 	 *
2151 	 * If mstate is non-zero the state has already been incorporated
2152 	 * into the message as part of a simulated abort.  Note that in this
2153 	 * situation the state may have already been removed from the RBTREE.
2154 	 *
2155 	 * If received msg is a command state is on staterd_tree.
2156 	 * If received msg is a reply state is on statewr_tree.
2157 	 * Otherwise there is no state (retain &iocom->state0)
2158 	 */
2159 	if (mstate) {
2160 		state = msg->state;
2161 	} else {
2162 		sdummy.msgid = msg->any.head.msgid;
2163 		if (msg->any.head.cmd & DMSGF_REVTRANS) {
2164 			state = RB_FIND(dmsg_state_tree,
2165 					&iocom->statewr_tree, &sdummy);
2166 		} else {
2167 			state = RB_FIND(dmsg_state_tree,
2168 					&iocom->staterd_tree, &sdummy);
2169 		}
2170 	}
2171 
2172 	if (DMsgDebugOpt) {
2173 		dmio_printf(iocom, 5, "msgrx:\tstate %p(%08x)",
2174 			    state, (state ? state->icmd : 0));
2175 		if (pstate != &iocom->state0) {
2176 			dmio_printf(iocom, 5,
2177 				    " pstate %p(%08x)",
2178 				    pstate, pstate->icmd);
2179 		}
2180 		dmio_printf(iocom, 5, "%s\n", "");
2181 	}
2182 
2183 	if (mstate) {
2184 		/* state already assigned to msg */
2185 	} else if (state) {
2186 		/*
2187 		 * Message over an existing transaction (CREATE should not
2188 		 * be set).
2189 		 */
2190 		dmsg_state_drop(msg->state);
2191 		dmsg_state_hold(state);
2192 		msg->state = state;
2193 		assert(pstate == state->parent);
2194 	} else {
2195 		/*
2196 		 * Either a new transaction (if CREATE set) or a one-off.
2197 		 */
2198 		state = pstate;
2199 	}
2200 
2201 	/*
2202 	 * Switch on CREATE, DELETE, REPLY, and also handle ABORT from
2203 	 * inside the case statements.
2204 	 *
2205 	 * Construct new state as necessary.
2206 	 */
2207 	switch(msg->any.head.cmd & (DMSGF_CREATE | DMSGF_DELETE |
2208 				    DMSGF_REPLY)) {
2209 	case DMSGF_CREATE:
2210 	case DMSGF_CREATE | DMSGF_DELETE:
2211 		/*
2212 		 * Create new sub-transaction under pstate.
2213 		 * (any DELETE is handled in post-processing of msg).
2214 		 *
2215 		 * (During routing the msgid was made unique for this
2216 		 * direction over the comlink, so our RB trees can be
2217 		 * iocom-based instead of state-based).
2218 		 */
2219 		if (state != pstate) {
2220 			dmio_printf(iocom, 2,
2221 				    "duplicate transaction %s\n",
2222 				    dmsg_msg_str(msg));
2223 			error = DMSG_IOQ_ERROR_TRANS;
2224 			assert(0);
2225 			break;
2226 		}
2227 
2228 		/*
2229 		 * Allocate the new state.
2230 		 */
2231 		state = malloc(sizeof(*state));
2232 		bzero(state, sizeof(*state));
2233 		atomic_add_int(&dmsg_state_count, 1);
2234 
2235 		TAILQ_INIT(&state->subq);
2236 		dmsg_state_hold(pstate);
2237 		state->parent = pstate;
2238 		state->iocom = iocom;
2239 		state->flags = DMSG_STATE_DYNAMIC |
2240 			       DMSG_STATE_OPPOSITE;
2241 		state->msgid = msg->any.head.msgid;
2242 		state->txcmd = DMSGF_REPLY;
2243 		state->rxcmd = msg->any.head.cmd & ~DMSGF_DELETE;
2244 		state->icmd = state->rxcmd & DMSGF_BASECMDMASK;
2245 		state->flags &= ~DMSG_STATE_NEW;
2246 		msg->state = state;
2247 
2248 		RB_INSERT(dmsg_state_tree, &iocom->staterd_tree, state);
2249 		if (TAILQ_EMPTY(&pstate->subq))
2250 			dmsg_state_hold(pstate);/* pstate->subq */
2251 		TAILQ_INSERT_TAIL(&pstate->subq, state, entry);
2252 		state->flags |= DMSG_STATE_SUBINSERTED |
2253 				DMSG_STATE_RBINSERTED;
2254 		dmsg_state_hold(state);		/* pstate->subq */
2255 		dmsg_state_hold(state);		/* state on rbtree */
2256 		dmsg_state_hold(state);		/* msg->state */
2257 
2258 		/*
2259 		 * If the parent is a relay set up the state handler to
2260 		 * automatically route the message.  Local processing will
2261 		 * not occur if set.
2262 		 *
2263 		 * (state relays are seeded by SPAN processing)
2264 		 */
2265 		if (pstate->relay)
2266 			state->func = dmsg_state_relay;
2267 		error = 0;
2268 		break;
2269 	case DMSGF_DELETE:
2270 		/*
2271 		 * Persistent state is expected but might not exist if an
2272 		 * ABORT+DELETE races the close.
2273 		 *
2274 		 * (any DELETE is handled in post-processing of msg).
2275 		 */
2276 		if (state == pstate) {
2277 			if (msg->any.head.cmd & DMSGF_ABORT) {
2278 				error = DMSG_IOQ_ERROR_EALREADY;
2279 			} else {
2280 				dmio_printf(iocom, 2,
2281 					    "missing-state %s\n",
2282 					    dmsg_msg_str(msg));
2283 				error = DMSG_IOQ_ERROR_TRANS;
2284 				assert(0);
2285 			}
2286 			break;
2287 		}
2288 
2289 		/*
2290 		 * Handle another ABORT+DELETE case if the msgid has already
2291 		 * been reused.
2292 		 */
2293 		if ((state->rxcmd & DMSGF_CREATE) == 0) {
2294 			if (msg->any.head.cmd & DMSGF_ABORT) {
2295 				error = DMSG_IOQ_ERROR_EALREADY;
2296 			} else {
2297 				dmio_printf(iocom, 2,
2298 					    "reused-state %s\n",
2299 					    dmsg_msg_str(msg));
2300 				error = DMSG_IOQ_ERROR_TRANS;
2301 				assert(0);
2302 			}
2303 			break;
2304 		}
2305 		error = 0;
2306 		break;
2307 	default:
2308 		/*
2309 		 * Check for mid-stream ABORT command received, otherwise
2310 		 * allow.
2311 		 */
2312 		if (msg->any.head.cmd & DMSGF_ABORT) {
2313 			if ((state == pstate) ||
2314 			    (state->rxcmd & DMSGF_CREATE) == 0) {
2315 				error = DMSG_IOQ_ERROR_EALREADY;
2316 				break;
2317 			}
2318 		}
2319 		error = 0;
2320 		break;
2321 	case DMSGF_REPLY | DMSGF_CREATE:
2322 	case DMSGF_REPLY | DMSGF_CREATE | DMSGF_DELETE:
2323 		/*
2324 		 * When receiving a reply with CREATE set the original
2325 		 * persistent state message should already exist.
2326 		 */
2327 		if (state == pstate) {
2328 			dmio_printf(iocom, 2, "no-state(r) %s\n",
2329 				    dmsg_msg_str(msg));
2330 			error = DMSG_IOQ_ERROR_TRANS;
2331 			assert(0);
2332 			break;
2333 		}
2334 		assert(((state->rxcmd ^ msg->any.head.cmd) & DMSGF_REPLY) == 0);
2335 		state->rxcmd = msg->any.head.cmd & ~DMSGF_DELETE;
2336 		error = 0;
2337 		break;
2338 	case DMSGF_REPLY | DMSGF_DELETE:
2339 		/*
2340 		 * Received REPLY+ABORT+DELETE in case where msgid has
2341 		 * already been fully closed, ignore the message.
2342 		 */
2343 		if (state == pstate) {
2344 			if (msg->any.head.cmd & DMSGF_ABORT) {
2345 				error = DMSG_IOQ_ERROR_EALREADY;
2346 			} else {
2347 				dmio_printf(iocom, 2,
2348 					    "no-state(r,d) %s\n",
2349 					    dmsg_msg_str(msg));
2350 				error = DMSG_IOQ_ERROR_TRANS;
2351 				assert(0);
2352 			}
2353 			break;
2354 		}
2355 
2356 		/*
2357 		 * Received REPLY+ABORT+DELETE in case where msgid has
2358 		 * already been reused for an unrelated message,
2359 		 * ignore the message.
2360 		 */
2361 		if ((state->rxcmd & DMSGF_CREATE) == 0) {
2362 			if (msg->any.head.cmd & DMSGF_ABORT) {
2363 				error = DMSG_IOQ_ERROR_EALREADY;
2364 			} else {
2365 				dmio_printf(iocom, 2,
2366 					    "reused-state(r,d) %s\n",
2367 					    dmsg_msg_str(msg));
2368 				error = DMSG_IOQ_ERROR_TRANS;
2369 				assert(0);
2370 			}
2371 			break;
2372 		}
2373 		error = 0;
2374 		break;
2375 	case DMSGF_REPLY:
2376 		/*
2377 		 * Check for mid-stream ABORT reply received to sent command.
2378 		 */
2379 		if (msg->any.head.cmd & DMSGF_ABORT) {
2380 			if (state == pstate ||
2381 			    (state->rxcmd & DMSGF_CREATE) == 0) {
2382 				error = DMSG_IOQ_ERROR_EALREADY;
2383 				break;
2384 			}
2385 		}
2386 		error = 0;
2387 		break;
2388 	}
2389 
2390 	/*
2391 	 * Calculate the easy-switch() transactional command.  Represents
2392 	 * the outer-transaction command for any transaction-create or
2393 	 * transaction-delete, and the inner message command for any
2394 	 * non-transaction or inside-transaction command.  tcmd will be
2395 	 * set to 0 for any messaging error condition.
2396 	 *
2397 	 * The two can be told apart because outer-transaction commands
2398 	 * always have a DMSGF_CREATE and/or DMSGF_DELETE flag.
2399 	 */
2400 	if (msg->any.head.cmd & (DMSGF_CREATE | DMSGF_DELETE)) {
2401 		if ((msg->state->flags & DMSG_STATE_ROOT) == 0) {
2402 			msg->tcmd = (state->icmd & DMSGF_BASECMDMASK) |
2403 				    (msg->any.head.cmd & (DMSGF_CREATE |
2404 							  DMSGF_DELETE |
2405 							  DMSGF_REPLY));
2406 		} else {
2407 			msg->tcmd = 0;
2408 		}
2409 	} else {
2410 		msg->tcmd = msg->any.head.cmd & DMSGF_CMDSWMASK;
2411 	}
2412 
2413 #ifdef DMSG_BLOCK_DEBUG
2414 	switch (msg->tcmd) {
2415 	case DMSG_BLK_READ | DMSGF_CREATE | DMSGF_DELETE:
2416 	case DMSG_BLK_WRITE | DMSGF_CREATE | DMSGF_DELETE:
2417 		dmio_printf(iocom, 4,
2418 			    "read  BIO %-3d %016jx %d@%016jx\n",
2419 			    biocount, msg->any.head.msgid,
2420 			    msg->any.blk_read.bytes,
2421 			    msg->any.blk_read.offset);
2422 		break;
2423 	case DMSG_BLK_READ | DMSGF_CREATE | DMSGF_DELETE | DMSGF_REPLY:
2424 	case DMSG_BLK_WRITE | DMSGF_CREATE | DMSGF_DELETE | DMSGF_REPLY:
2425 		dmio_printf(iocom, 4,
2426 			    "rread BIO %-3d %016jx %d@%016jx\n",
2427 			    biocount, msg->any.head.msgid,
2428 			    msg->any.blk_read.bytes,
2429 			    msg->any.blk_read.offset);
2430 		break;
2431 	default:
2432 		break;
2433 	}
2434 #endif
2435 
2436 	/*
2437 	 * Adjust state, mark receive side as DELETED if appropriate and
2438 	 * adjust RB tree if both sides are DELETED.  cleanuprx handles
2439 	 * the rest after the state callback returns.
2440 	 */
2441 	assert(msg->state->iocom == iocom);
2442 	assert(msg->state == state);
2443 
2444 	if (state->flags & DMSG_STATE_ROOT) {
2445 		/*
2446 		 * Nothing to do for non-transactional messages.
2447 		 */
2448 	} else if (msg->any.head.cmd & DMSGF_DELETE) {
2449 		/*
2450 		 * Message terminating transaction, remove the state from
2451 		 * the RB tree if the full transaction is now complete.
2452 		 * The related state, subq, and parent link is retained
2453 		 * until after the state callback is complete.
2454 		 */
2455 		assert((state->rxcmd & DMSGF_DELETE) == 0);
2456 		state->rxcmd |= DMSGF_DELETE;
2457 		if (state->txcmd & DMSGF_DELETE) {
2458 			assert(state->flags & DMSG_STATE_RBINSERTED);
2459 			if (state->rxcmd & DMSGF_REPLY) {
2460 				assert(msg->any.head.cmd & DMSGF_REPLY);
2461 				RB_REMOVE(dmsg_state_tree,
2462 					  &iocom->statewr_tree, state);
2463 			} else {
2464 				assert((msg->any.head.cmd & DMSGF_REPLY) == 0);
2465 				RB_REMOVE(dmsg_state_tree,
2466 					  &iocom->staterd_tree, state);
2467 			}
2468 			state->flags &= ~DMSG_STATE_RBINSERTED;
2469 			dmsg_state_drop(state);
2470 		}
2471 	}
2472 
2473 	pthread_mutex_unlock(&iocom->mtx);
2474 
2475 	if (DMsgDebugOpt && error)
2476 		dmio_printf(iocom, 1, "msgrx: error %d\n", error);
2477 
2478 	return (error);
2479 }
2480 
2481 /*
2482  * Route the message and handle pair-state processing.
2483  */
2484 void
2485 dmsg_state_relay(dmsg_msg_t *lmsg)
2486 {
2487 	dmsg_state_t *lpstate;
2488 	dmsg_state_t *rpstate;
2489 	dmsg_state_t *lstate;
2490 	dmsg_state_t *rstate;
2491 	dmsg_msg_t *rmsg;
2492 
2493 #ifdef DMSG_BLOCK_DEBUG
2494 	switch (lmsg->tcmd) {
2495 	case DMSG_BLK_OPEN | DMSGF_CREATE:
2496 		dmio_printf(iocom, 4, "%s\n",
2497 			    "relay BIO_OPEN (CREATE)");
2498 		break;
2499 	case DMSG_BLK_OPEN | DMSGF_DELETE:
2500 		dmio_printf(iocom, 4, "%s\n",
2501 			    "relay BIO_OPEN (DELETE)");
2502 		break;
2503 	case DMSG_BLK_READ | DMSGF_CREATE | DMSGF_DELETE:
2504 	case DMSG_BLK_WRITE | DMSGF_CREATE | DMSGF_DELETE:
2505 		atomic_add_int(&biocount, 1);
2506 		dmio_printf(iocom, 4,
2507 			    "relay BIO %-3d %016jx %d@%016jx\n",
2508 			    biocount, lmsg->any.head.msgid,
2509 			    lmsg->any.blk_read.bytes,
2510 			    lmsg->any.blk_read.offset);
2511 		break;
2512 	case DMSG_BLK_READ | DMSGF_CREATE | DMSGF_DELETE | DMSGF_REPLY:
2513 	case DMSG_BLK_WRITE | DMSGF_CREATE | DMSGF_DELETE | DMSGF_REPLY:
2514 		dmio_printf(iocom, 4,
2515 			    "retrn BIO %-3d %016jx %d@%016jx\n",
2516 			    biocount, lmsg->any.head.msgid,
2517 			    lmsg->any.blk_read.bytes,
2518 			    lmsg->any.blk_read.offset);
2519 		atomic_add_int(&biocount, -1);
2520 		break;
2521 	default:
2522 		break;
2523 	}
2524 #endif
2525 
2526 	if ((lmsg->any.head.cmd & (DMSGF_CREATE | DMSGF_REPLY)) ==
2527 	    DMSGF_CREATE) {
2528 		/*
2529 		 * New sub-transaction, establish new state and relay.
2530 		 */
2531 		lstate = lmsg->state;
2532 		lpstate = lstate->parent;
2533 		rpstate = lpstate->relay;
2534 		assert(lstate->relay == NULL);
2535 		assert(rpstate != NULL);
2536 
2537 		rmsg = dmsg_msg_alloc(rpstate, 0,
2538 				      lmsg->any.head.cmd,
2539 				      dmsg_state_relay, NULL);
2540 		rstate = rmsg->state;
2541 		rstate->relay = lstate;
2542 		lstate->relay = rstate;
2543 		dmsg_state_hold(lstate);
2544 		dmsg_state_hold(rstate);
2545 	} else {
2546 		/*
2547 		 * State & relay already established
2548 		 */
2549 		lstate = lmsg->state;
2550 		rstate = lstate->relay;
2551 		assert(rstate != NULL);
2552 
2553 		assert((rstate->txcmd & DMSGF_DELETE) == 0);
2554 
2555 #if 0
2556 		if (lstate->flags & DMSG_STATE_ABORTING) {
2557 			dmio_printf(iocom, 4,
2558 				    "relay: relay lost link l=%p r=%p\n",
2559 				    lstate, rstate);
2560 			dmsg_simulate_failure(rstate, 0, DMSG_ERR_LOSTLINK);
2561 		}
2562 #endif
2563 
2564 		rmsg = dmsg_msg_alloc(rstate, 0,
2565 				      lmsg->any.head.cmd,
2566 				      dmsg_state_relay, NULL);
2567 	}
2568 	if (lmsg->hdr_size > sizeof(lmsg->any.head)) {
2569 		bcopy(&lmsg->any.head + 1, &rmsg->any.head + 1,
2570 		      lmsg->hdr_size - sizeof(lmsg->any.head));
2571 	}
2572 	rmsg->any.head.error = lmsg->any.head.error;
2573 	rmsg->any.head.reserved02 = lmsg->any.head.reserved02;
2574 	rmsg->any.head.link_verifier = lmsg->any.head.link_verifier;
2575 	rmsg->aux_size = lmsg->aux_size;
2576 	rmsg->aux_data = lmsg->aux_data;
2577 	lmsg->aux_data = NULL;
2578 
2579 	dmsg_msg_write(rmsg);
2580 }
2581 
2582 /*
2583  * Cleanup and retire msg after issuing the state callback.  The state
2584  * has already been removed from the RB tree.  The subq and msg must be
2585  * cleaned up.
2586  *
2587  * Called with the iocom mutex held (to handle subq disconnection).
2588  */
2589 void
2590 dmsg_state_cleanuprx(dmsg_iocom_t *iocom, dmsg_msg_t *msg)
2591 {
2592 	dmsg_state_t *state;
2593 
2594 	assert(msg->state->iocom == iocom);
2595 	state = msg->state;
2596 	if (state->flags & DMSG_STATE_ROOT) {
2597 		/*
2598 		 * Free a non-transactional message, there is no state
2599 		 * to worry about.
2600 		 */
2601 		dmsg_msg_free(msg);
2602 	} else if ((state->flags & DMSG_STATE_SUBINSERTED) &&
2603 		   (state->rxcmd & DMSGF_DELETE) &&
2604 		   (state->txcmd & DMSGF_DELETE)) {
2605 		/*
2606 		 * Must disconnect from parent and drop relay.
2607 		 */
2608 		dmsg_subq_delete(state);
2609 		if (state->relay) {
2610 			dmsg_state_drop(state->relay);
2611 			state->relay = NULL;
2612 		}
2613 		dmsg_msg_free(msg);
2614 	} else {
2615 		/*
2616 		 * Message not terminating transaction, leave state intact
2617 		 * and free message if it isn't the CREATE message.
2618 		 */
2619 		dmsg_msg_free(msg);
2620 	}
2621 }
2622 
2623 /*
2624  * Clean up the state after pulling out needed fields and queueing the
2625  * message for transmission.   This occurs in dmsg_msg_write().
2626  *
2627  * Called with the mutex locked.
2628  */
2629 static void
2630 dmsg_state_cleanuptx(dmsg_iocom_t *iocom, dmsg_msg_t *msg)
2631 {
2632 	dmsg_state_t *state;
2633 
2634 	assert(iocom == msg->state->iocom);
2635 	state = msg->state;
2636 
2637 	dmsg_state_hold(state);
2638 
2639 	if (state->flags & DMSG_STATE_ROOT) {
2640 		;
2641 	} else if (msg->any.head.cmd & DMSGF_DELETE) {
2642 		/*
2643 		 * Message terminating transaction, destroy the related
2644 		 * state, the original message, and this message (if it
2645 		 * isn't the original message due to a CREATE|DELETE).
2646 		 *
2647 		 * It's possible for governing state to terminate while
2648 		 * sub-transactions still exist.  This is allowed but
2649 		 * will cause sub-transactions to recursively fail.
2650 		 * Further reception of sub-transaction messages will be
2651 		 * impossible because the circuit will no longer exist.
2652 		 * (XXX need code to make sure that happens properly).
2653 		 *
2654 		 * NOTE: It is possible for a fafilure to terminate the
2655 		 *	 state after we have written the message but before
2656 		 *	 we are able to call cleanuptx, so txcmd might already
2657 		 *	 have DMSGF_DELETE set.
2658 		 */
2659 		if ((state->txcmd & DMSGF_DELETE) == 0 &&
2660 		    (state->rxcmd & DMSGF_DELETE)) {
2661 			state->txcmd |= DMSGF_DELETE;
2662 			assert(state->flags & DMSG_STATE_RBINSERTED);
2663 			if (state->txcmd & DMSGF_REPLY) {
2664 				assert(msg->any.head.cmd & DMSGF_REPLY);
2665 				RB_REMOVE(dmsg_state_tree,
2666 					  &iocom->staterd_tree, state);
2667 			} else {
2668 				assert((msg->any.head.cmd & DMSGF_REPLY) == 0);
2669 				RB_REMOVE(dmsg_state_tree,
2670 					  &iocom->statewr_tree, state);
2671 			}
2672 			state->flags &= ~DMSG_STATE_RBINSERTED;
2673 			dmsg_subq_delete(state);
2674 
2675 			if (state->relay) {
2676 				dmsg_state_drop(state->relay);
2677 				state->relay = NULL;
2678 			}
2679 			dmsg_state_drop(state);	/* state->rbtree */
2680 		} else if ((state->txcmd & DMSGF_DELETE) == 0) {
2681 			state->txcmd |= DMSGF_DELETE;
2682 		}
2683 	}
2684 
2685 	/*
2686 	 * Deferred abort after transmission.
2687 	 */
2688 	if ((state->flags & (DMSG_STATE_ABORTING | DMSG_STATE_DYING)) &&
2689 	    (state->rxcmd & DMSGF_DELETE) == 0) {
2690 		dmio_printf(iocom, 4,
2691 			    "cleanuptx: state=%p "
2692 			    "executing deferred abort\n",
2693 			    state);
2694 		state->flags &= ~DMSG_STATE_ABORTING;
2695 		dmsg_simulate_failure(state, 1, DMSG_ERR_LOSTLINK);
2696 	}
2697 
2698 	dmsg_state_drop(state);
2699 }
2700 
2701 /*
2702  * Called with or without locks
2703  */
2704 void
2705 dmsg_state_hold(dmsg_state_t *state)
2706 {
2707 	atomic_add_int(&state->refs, 1);
2708 }
2709 
2710 void
2711 dmsg_state_drop(dmsg_state_t *state)
2712 {
2713 	assert(state->refs > 0);
2714 	if (atomic_fetchadd_int(&state->refs, -1) == 1)
2715 		dmsg_state_free(state);
2716 }
2717 
2718 /*
2719  * Called with iocom locked
2720  */
2721 static void
2722 dmsg_state_free(dmsg_state_t *state)
2723 {
2724 	atomic_add_int(&dmsg_state_count, -1);
2725 	dmio_printf(state->iocom, 5, "terminate state %p\n", state);
2726 	assert((state->flags & (DMSG_STATE_ROOT |
2727 				DMSG_STATE_SUBINSERTED |
2728 				DMSG_STATE_RBINSERTED)) == 0);
2729 	assert(TAILQ_EMPTY(&state->subq));
2730 	assert(state->refs == 0);
2731 	if (state->any.any != NULL)   /* XXX avoid deadlock w/exit & kernel */
2732 		closefrom(3);
2733 	assert(state->any.any == NULL);
2734 	free(state);
2735 }
2736 
2737 /*
2738  * This swaps endian for a hammer2_msg_hdr.  Note that the extended
2739  * header is not adjusted, just the core header.
2740  */
2741 void
2742 dmsg_bswap_head(dmsg_hdr_t *head)
2743 {
2744 	head->magic	= bswap16(head->magic);
2745 	head->reserved02 = bswap16(head->reserved02);
2746 	head->salt	= bswap32(head->salt);
2747 
2748 	head->msgid	= bswap64(head->msgid);
2749 	head->circuit	= bswap64(head->circuit);
2750 	head->link_verifier= bswap64(head->link_verifier);
2751 
2752 	head->cmd	= bswap32(head->cmd);
2753 	head->aux_crc	= bswap32(head->aux_crc);
2754 	head->aux_bytes	= bswap32(head->aux_bytes);
2755 	head->error	= bswap32(head->error);
2756 	head->aux_descr = bswap64(head->aux_descr);
2757 	head->reserved38= bswap32(head->reserved38);
2758 	head->hdr_crc	= bswap32(head->hdr_crc);
2759 }
2760