xref: /illumos-gate/usr/src/uts/common/inet/sctp/sctp_bind.c (revision 89b2a9fbeabf42fa54594df0e5927bcc50a07cc9)
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/systm.h>
29 #include <sys/stream.h>
30 #include <sys/cmn_err.h>
31 #include <sys/kmem.h>
32 #define	_SUN_TPI_VERSION 2
33 #include <sys/tihdr.h>
34 #include <sys/stropts.h>
35 #include <sys/socket.h>
36 #include <sys/random.h>
37 #include <sys/policy.h>
38 #include <sys/tsol/tndb.h>
39 #include <sys/tsol/tnet.h>
40 
41 #include <netinet/in.h>
42 #include <netinet/ip6.h>
43 
44 #include <inet/common.h>
45 #include <inet/ip.h>
46 #include <inet/ip6.h>
47 #include <inet/ipclassifier.h>
48 #include "sctp_impl.h"
49 #include "sctp_asconf.h"
50 #include "sctp_addr.h"
51 
52 /*
53  * Returns 0 on success, EACCES on permission failure.
54  */
55 static int
56 sctp_select_port(sctp_t *sctp, in_port_t *requested_port, int *user_specified)
57 {
58 	sctp_stack_t	*sctps = sctp->sctp_sctps;
59 	conn_t		*connp = sctp->sctp_connp;
60 
61 	/*
62 	 * Get a valid port (within the anonymous range and should not
63 	 * be a privileged one) to use if the user has not given a port.
64 	 * If multiple threads are here, they may all start with
65 	 * with the same initial port. But, it should be fine as long as
66 	 * sctp_bindi will ensure that no two threads will be assigned
67 	 * the same port.
68 	 */
69 	if (*requested_port == 0) {
70 		*requested_port = sctp_update_next_port(
71 		    sctps->sctps_next_port_to_try,
72 		    crgetzone(connp->conn_cred), sctps);
73 		if (*requested_port == 0)
74 			return (EACCES);
75 		*user_specified = 0;
76 	} else {
77 		int i;
78 		boolean_t priv = B_FALSE;
79 
80 		/*
81 		 * If the requested_port is in the well-known privileged range,
82 		 * verify that the stream was opened by a privileged user.
83 		 * Note: No locks are held when inspecting sctp_g_*epriv_ports
84 		 * but instead the code relies on:
85 		 * - the fact that the address of the array and its size never
86 		 *   changes
87 		 * - the atomic assignment of the elements of the array
88 		 */
89 		if (*requested_port < sctps->sctps_smallest_nonpriv_port) {
90 			priv = B_TRUE;
91 		} else {
92 			for (i = 0; i < sctps->sctps_g_num_epriv_ports; i++) {
93 				if (*requested_port ==
94 				    sctps->sctps_g_epriv_ports[i]) {
95 					priv = B_TRUE;
96 					break;
97 				}
98 			}
99 		}
100 		if (priv) {
101 			/*
102 			 * sctp_bind() should take a cred_t argument so that
103 			 * we can use it here.
104 			 */
105 			if (secpolicy_net_privaddr(connp->conn_cred,
106 			    *requested_port, IPPROTO_SCTP) != 0) {
107 				dprint(1,
108 				    ("sctp_bind(x): no prive for port %d",
109 				    *requested_port));
110 				return (EACCES);
111 			}
112 		}
113 		*user_specified = 1;
114 	}
115 
116 	return (0);
117 }
118 
119 int
120 sctp_listen(sctp_t *sctp)
121 {
122 	sctp_tf_t	*tf;
123 	sctp_stack_t	*sctps = sctp->sctp_sctps;
124 	conn_t		*connp = sctp->sctp_connp;
125 
126 	RUN_SCTP(sctp);
127 	/*
128 	 * TCP handles listen() increasing the backlog, need to check
129 	 * if it should be handled here too
130 	 */
131 	if (sctp->sctp_state > SCTPS_BOUND ||
132 	    (sctp->sctp_connp->conn_state_flags & CONN_CLOSING)) {
133 		WAKE_SCTP(sctp);
134 		return (EINVAL);
135 	}
136 
137 	/* Do an anonymous bind for unbound socket doing listen(). */
138 	if (sctp->sctp_nsaddrs == 0) {
139 		struct sockaddr_storage ss;
140 		int ret;
141 
142 		bzero(&ss, sizeof (ss));
143 		ss.ss_family = connp->conn_family;
144 
145 		WAKE_SCTP(sctp);
146 		if ((ret = sctp_bind(sctp, (struct sockaddr *)&ss,
147 		    sizeof (ss))) != 0)
148 			return (ret);
149 		RUN_SCTP(sctp)
150 	}
151 
152 	/* Cache things in the ixa without any refhold */
153 	connp->conn_ixa->ixa_cred = connp->conn_cred;
154 	connp->conn_ixa->ixa_cpid = connp->conn_cpid;
155 	if (is_system_labeled())
156 		connp->conn_ixa->ixa_tsl = crgetlabel(connp->conn_cred);
157 
158 	sctp->sctp_state = SCTPS_LISTEN;
159 	(void) random_get_pseudo_bytes(sctp->sctp_secret, SCTP_SECRET_LEN);
160 	sctp->sctp_last_secret_update = ddi_get_lbolt64();
161 	bzero(sctp->sctp_old_secret, SCTP_SECRET_LEN);
162 	tf = &sctps->sctps_listen_fanout[SCTP_LISTEN_HASH(
163 	    ntohs(connp->conn_lport))];
164 	sctp_listen_hash_insert(tf, sctp);
165 	WAKE_SCTP(sctp);
166 	return (0);
167 }
168 
169 /*
170  * Bind the sctp_t to a sockaddr, which includes an address and other
171  * information, such as port or flowinfo.
172  */
173 int
174 sctp_bind(sctp_t *sctp, struct sockaddr *sa, socklen_t len)
175 {
176 	int		user_specified;
177 	boolean_t	bind_to_req_port_only;
178 	in_port_t	requested_port;
179 	in_port_t	allocated_port;
180 	int		err = 0;
181 	conn_t		*connp = sctp->sctp_connp;
182 	uint_t		scope_id;
183 	sin_t		*sin;
184 	sin6_t		*sin6;
185 
186 	ASSERT(sctp != NULL);
187 
188 	RUN_SCTP(sctp);
189 
190 	if ((sctp->sctp_state >= SCTPS_BOUND) ||
191 	    (sctp->sctp_connp->conn_state_flags & CONN_CLOSING) ||
192 	    (sa == NULL || len == 0)) {
193 		/*
194 		 * Multiple binds not allowed for any SCTP socket
195 		 * Also binding with null address is not supported.
196 		 */
197 		err = EINVAL;
198 		goto done;
199 	}
200 
201 	switch (sa->sa_family) {
202 	case AF_INET:
203 		sin = (sin_t *)sa;
204 		if (len < sizeof (struct sockaddr_in) ||
205 		    connp->conn_family == AF_INET6) {
206 			err = EINVAL;
207 			goto done;
208 		}
209 		requested_port = ntohs(sin->sin_port);
210 		break;
211 	case AF_INET6:
212 		sin6 = (sin6_t *)sa;
213 		if (len < sizeof (struct sockaddr_in6) ||
214 		    connp->conn_family == AF_INET) {
215 			err = EINVAL;
216 			goto done;
217 		}
218 		requested_port = ntohs(sin6->sin6_port);
219 		/* Set the flowinfo. */
220 		connp->conn_flowinfo =
221 		    sin6->sin6_flowinfo & ~IPV6_VERS_AND_FLOW_MASK;
222 
223 		scope_id = sin6->sin6_scope_id;
224 		if (scope_id != 0 && IN6_IS_ADDR_LINKSCOPE(&sin6->sin6_addr)) {
225 			connp->conn_ixa->ixa_flags |= IXAF_SCOPEID_SET;
226 			connp->conn_ixa->ixa_scopeid = scope_id;
227 			connp->conn_incoming_ifindex = scope_id;
228 		} else {
229 			connp->conn_ixa->ixa_flags &= ~IXAF_SCOPEID_SET;
230 			connp->conn_incoming_ifindex = connp->conn_bound_if;
231 		}
232 		break;
233 	default:
234 		err = EAFNOSUPPORT;
235 		goto done;
236 	}
237 	bind_to_req_port_only = requested_port == 0 ? B_FALSE : B_TRUE;
238 
239 	err = sctp_select_port(sctp, &requested_port, &user_specified);
240 	if (err != 0)
241 		goto done;
242 
243 	if ((err = sctp_bind_add(sctp, sa, 1, B_TRUE,
244 	    user_specified == 1 ? htons(requested_port) : 0)) != 0) {
245 		goto done;
246 	}
247 	err = sctp_bindi(sctp, requested_port, bind_to_req_port_only,
248 	    user_specified, &allocated_port);
249 	if (err != 0) {
250 		sctp_free_saddrs(sctp);
251 	} else {
252 		ASSERT(sctp->sctp_state == SCTPS_BOUND);
253 	}
254 done:
255 	WAKE_SCTP(sctp);
256 	return (err);
257 }
258 
259 /*
260  * Perform bind/unbind operation of a list of addresses on a sctp_t
261  */
262 int
263 sctp_bindx(sctp_t *sctp, const void *addrs, int addrcnt, int bindop)
264 {
265 	ASSERT(sctp != NULL);
266 	ASSERT(addrs != NULL);
267 	ASSERT(addrcnt > 0);
268 
269 	switch (bindop) {
270 	case SCTP_BINDX_ADD_ADDR:
271 		return (sctp_bind_add(sctp, addrs, addrcnt, B_FALSE,
272 		    sctp->sctp_connp->conn_lport));
273 	case SCTP_BINDX_REM_ADDR:
274 		return (sctp_bind_del(sctp, addrs, addrcnt, B_FALSE));
275 	default:
276 		return (EINVAL);
277 	}
278 }
279 
280 /*
281  * Add a list of addresses to a sctp_t.
282  */
283 int
284 sctp_bind_add(sctp_t *sctp, const void *addrs, uint32_t addrcnt,
285     boolean_t caller_hold_lock, in_port_t port)
286 {
287 	int		err = 0;
288 	boolean_t	do_asconf = B_FALSE;
289 	sctp_stack_t	*sctps = sctp->sctp_sctps;
290 	conn_t		*connp = sctp->sctp_connp;
291 
292 	if (!caller_hold_lock)
293 		RUN_SCTP(sctp);
294 
295 	if (sctp->sctp_state > SCTPS_ESTABLISHED ||
296 	    (sctp->sctp_connp->conn_state_flags & CONN_CLOSING)) {
297 		if (!caller_hold_lock)
298 			WAKE_SCTP(sctp);
299 		return (EINVAL);
300 	}
301 
302 	if (sctp->sctp_state > SCTPS_LISTEN) {
303 		/*
304 		 * Let's do some checking here rather than undoing the
305 		 * add later (for these reasons).
306 		 */
307 		if (!sctps->sctps_addip_enabled ||
308 		    !sctp->sctp_understands_asconf ||
309 		    !sctp->sctp_understands_addip) {
310 			if (!caller_hold_lock)
311 				WAKE_SCTP(sctp);
312 			return (EINVAL);
313 		}
314 		do_asconf = B_TRUE;
315 	}
316 	/*
317 	 * On a clustered node, for an inaddr_any bind, we will pass the list
318 	 * of all the addresses in the global list, minus any address on the
319 	 * loopback interface, and expect the clustering susbsystem to give us
320 	 * the correct list for the 'port'. For explicit binds we give the
321 	 * list of addresses  and the clustering module validates it for the
322 	 * 'port'.
323 	 *
324 	 * On a non-clustered node, cl_sctp_check_addrs will be NULL and
325 	 * we proceed as usual.
326 	 */
327 	if (cl_sctp_check_addrs != NULL) {
328 		uchar_t		*addrlist = NULL;
329 		size_t		size = 0;
330 		int		unspec = 0;
331 		boolean_t	do_listen;
332 		uchar_t		*llist = NULL;
333 		size_t		lsize = 0;
334 
335 		/*
336 		 * If we are adding addresses after listening, but before
337 		 * an association is established, we need to update the
338 		 * clustering module with this info.
339 		 */
340 		do_listen = !do_asconf && sctp->sctp_state > SCTPS_BOUND &&
341 		    cl_sctp_listen != NULL;
342 
343 		err = sctp_get_addrlist(sctp, addrs, &addrcnt, &addrlist,
344 		    &unspec, &size);
345 		if (err != 0) {
346 			ASSERT(addrlist == NULL);
347 			ASSERT(addrcnt == 0);
348 			ASSERT(size == 0);
349 			if (!caller_hold_lock)
350 				WAKE_SCTP(sctp);
351 			SCTP_KSTAT(sctps, sctp_cl_check_addrs);
352 			return (err);
353 		}
354 		ASSERT(addrlist != NULL);
355 		(*cl_sctp_check_addrs)(connp->conn_family, port, &addrlist,
356 		    size, &addrcnt, unspec == 1);
357 		if (addrcnt == 0) {
358 			/* We free the list */
359 			kmem_free(addrlist, size);
360 			if (!caller_hold_lock)
361 				WAKE_SCTP(sctp);
362 			return (EINVAL);
363 		}
364 		if (do_listen) {
365 			lsize = sizeof (in6_addr_t) * addrcnt;
366 			llist = kmem_alloc(lsize, KM_SLEEP);
367 		}
368 		err = sctp_valid_addr_list(sctp, addrlist, addrcnt, llist,
369 		    lsize);
370 		if (err == 0 && do_listen) {
371 			(*cl_sctp_listen)(connp->conn_family, llist,
372 			    addrcnt, connp->conn_lport);
373 			/* list will be freed by the clustering module */
374 		} else if (err != 0 && llist != NULL) {
375 			kmem_free(llist, lsize);
376 		}
377 		/* free the list we allocated */
378 		kmem_free(addrlist, size);
379 	} else {
380 		err = sctp_valid_addr_list(sctp, addrs, addrcnt, NULL, 0);
381 	}
382 	if (err != 0) {
383 		if (!caller_hold_lock)
384 			WAKE_SCTP(sctp);
385 		return (err);
386 	}
387 	/* Need to send  ASCONF messages */
388 	if (do_asconf) {
389 		err = sctp_add_ip(sctp, addrs, addrcnt);
390 		if (err != 0) {
391 			sctp_del_saddr_list(sctp, addrs, addrcnt, B_FALSE);
392 			if (!caller_hold_lock)
393 				WAKE_SCTP(sctp);
394 			return (err);
395 		}
396 	}
397 	if (!caller_hold_lock)
398 		WAKE_SCTP(sctp);
399 	return (0);
400 }
401 
402 /*
403  * Remove one or more addresses bound to the sctp_t.
404  */
405 int
406 sctp_bind_del(sctp_t *sctp, const void *addrs, uint32_t addrcnt,
407     boolean_t caller_hold_lock)
408 {
409 	int		error = 0;
410 	boolean_t	do_asconf = B_FALSE;
411 	uchar_t		*ulist = NULL;
412 	size_t		usize = 0;
413 	sctp_stack_t	*sctps = sctp->sctp_sctps;
414 	conn_t		*connp = sctp->sctp_connp;
415 
416 	if (!caller_hold_lock)
417 		RUN_SCTP(sctp);
418 
419 	if (sctp->sctp_state > SCTPS_ESTABLISHED ||
420 	    (sctp->sctp_connp->conn_state_flags & CONN_CLOSING)) {
421 		if (!caller_hold_lock)
422 			WAKE_SCTP(sctp);
423 		return (EINVAL);
424 	}
425 	/*
426 	 * Fail the remove if we are beyond listen, but can't send this
427 	 * to the peer.
428 	 */
429 	if (sctp->sctp_state > SCTPS_LISTEN) {
430 		if (!sctps->sctps_addip_enabled ||
431 		    !sctp->sctp_understands_asconf ||
432 		    !sctp->sctp_understands_addip) {
433 			if (!caller_hold_lock)
434 				WAKE_SCTP(sctp);
435 			return (EINVAL);
436 		}
437 		do_asconf = B_TRUE;
438 	}
439 
440 	/* Can't delete the last address nor all of the addresses */
441 	if (sctp->sctp_nsaddrs == 1 || addrcnt >= sctp->sctp_nsaddrs) {
442 		if (!caller_hold_lock)
443 			WAKE_SCTP(sctp);
444 		return (EINVAL);
445 	}
446 
447 	if (cl_sctp_unlisten != NULL && !do_asconf &&
448 	    sctp->sctp_state > SCTPS_BOUND) {
449 		usize = sizeof (in6_addr_t) * addrcnt;
450 		ulist = kmem_alloc(usize, KM_SLEEP);
451 	}
452 
453 	error = sctp_del_ip(sctp, addrs, addrcnt, ulist, usize);
454 	if (error != 0) {
455 		if (ulist != NULL)
456 			kmem_free(ulist, usize);
457 		if (!caller_hold_lock)
458 			WAKE_SCTP(sctp);
459 		return (error);
460 	}
461 	/* ulist will be non-NULL only if cl_sctp_unlisten is non-NULL */
462 	if (ulist != NULL) {
463 		ASSERT(cl_sctp_unlisten != NULL);
464 		(*cl_sctp_unlisten)(connp->conn_family, ulist, addrcnt,
465 		    connp->conn_lport);
466 		/* ulist will be freed by the clustering module */
467 	}
468 	if (!caller_hold_lock)
469 		WAKE_SCTP(sctp);
470 	return (error);
471 }
472 
473 /*
474  * Returns 0 for success, errno value otherwise.
475  *
476  * If the "bind_to_req_port_only" parameter is set and the requested port
477  * number is available, then set allocated_port to it.  If not available,
478  * return an error.
479  *
480  * If the "bind_to_req_port_only" parameter is not set and the requested port
481  * number is available, then set allocated_port to it.  If not available,
482  * find the first anonymous port we can and set allocated_port to that.  If no
483  * anonymous ports are available, return an error.
484  *
485  * In either case, when succeeding, update the sctp_t to record the port number
486  * and insert it in the bind hash table.
487  */
488 int
489 sctp_bindi(sctp_t *sctp, in_port_t port, boolean_t bind_to_req_port_only,
490     int user_specified, in_port_t *allocated_port)
491 {
492 	/* number of times we have run around the loop */
493 	int count = 0;
494 	/* maximum number of times to run around the loop */
495 	int loopmax;
496 	sctp_stack_t	*sctps = sctp->sctp_sctps;
497 	conn_t		*connp = sctp->sctp_connp;
498 	zone_t *zone = crgetzone(connp->conn_cred);
499 	zoneid_t zoneid = connp->conn_zoneid;
500 
501 	/*
502 	 * Lookup for free addresses is done in a loop and "loopmax"
503 	 * influences how long we spin in the loop
504 	 */
505 	if (bind_to_req_port_only) {
506 		/*
507 		 * If the requested port is busy, don't bother to look
508 		 * for a new one. Setting loop maximum count to 1 has
509 		 * that effect.
510 		 */
511 		loopmax = 1;
512 	} else {
513 		/*
514 		 * If the requested port is busy, look for a free one
515 		 * in the anonymous port range.
516 		 * Set loopmax appropriately so that one does not look
517 		 * forever in the case all of the anonymous ports are in use.
518 		 */
519 		loopmax = (sctps->sctps_largest_anon_port -
520 		    sctps->sctps_smallest_anon_port + 1);
521 	}
522 	do {
523 		uint16_t	lport;
524 		sctp_tf_t	*tbf;
525 		sctp_t		*lsctp;
526 		int		addrcmp;
527 
528 		lport = htons(port);
529 
530 		/*
531 		 * Ensure that the sctp_t is not currently in the bind hash.
532 		 * Hold the lock on the hash bucket to ensure that
533 		 * the duplicate check plus the insertion is an atomic
534 		 * operation.
535 		 *
536 		 * This function does an inline lookup on the bind hash list
537 		 * Make sure that we access only members of sctp_t
538 		 * and that we don't look at sctp_sctp, since we are not
539 		 * doing a SCTPB_REFHOLD. For more details please see the notes
540 		 * in sctp_compress()
541 		 */
542 		sctp_bind_hash_remove(sctp);
543 		tbf = &sctps->sctps_bind_fanout[SCTP_BIND_HASH(port)];
544 		mutex_enter(&tbf->tf_lock);
545 		for (lsctp = tbf->tf_sctp; lsctp != NULL;
546 		    lsctp = lsctp->sctp_bind_hash) {
547 			conn_t *lconnp = lsctp->sctp_connp;
548 
549 			if (lport != lconnp->conn_lport ||
550 			    lsctp->sctp_state < SCTPS_BOUND)
551 				continue;
552 
553 			/*
554 			 * On a labeled system, we must treat bindings to ports
555 			 * on shared IP addresses by sockets with MAC exemption
556 			 * privilege as being in all zones, as there's
557 			 * otherwise no way to identify the right receiver.
558 			 */
559 			if (lconnp->conn_zoneid != zoneid &&
560 			    lconnp->conn_mac_mode == CONN_MAC_DEFAULT &&
561 			    connp->conn_mac_mode == CONN_MAC_DEFAULT)
562 				continue;
563 
564 			addrcmp = sctp_compare_saddrs(sctp, lsctp);
565 			if (addrcmp != SCTP_ADDR_DISJOINT) {
566 				if (!connp->conn_reuseaddr) {
567 					/* in use */
568 					break;
569 				} else if (lsctp->sctp_state == SCTPS_BOUND ||
570 				    lsctp->sctp_state == SCTPS_LISTEN) {
571 					/*
572 					 * socket option SO_REUSEADDR is set
573 					 * on the binding sctp_t.
574 					 *
575 					 * We have found a match of IP source
576 					 * address and source port, which is
577 					 * refused regardless of the
578 					 * SO_REUSEADDR setting, so we break.
579 					 */
580 					break;
581 				}
582 			}
583 		}
584 		if (lsctp != NULL) {
585 			/* The port number is busy */
586 			mutex_exit(&tbf->tf_lock);
587 		} else {
588 			if (is_system_labeled()) {
589 				mlp_type_t addrtype, mlptype;
590 				uint_t ipversion;
591 
592 				/*
593 				 * On a labeled system we must check the type
594 				 * of the binding requested by the user (either
595 				 * MLP or SLP on shared and private addresses),
596 				 * and that the user's requested binding
597 				 * is permitted.
598 				 */
599 				if (connp->conn_family == AF_INET)
600 					ipversion = IPV4_VERSION;
601 				else
602 					ipversion = IPV6_VERSION;
603 
604 				addrtype = tsol_mlp_addr_type(
605 				    connp->conn_allzones ? ALL_ZONES :
606 				    zone->zone_id,
607 				    ipversion,
608 				    connp->conn_family == AF_INET ?
609 				    (void *)&sctp->sctp_ipha->ipha_src :
610 				    (void *)&sctp->sctp_ip6h->ip6_src,
611 				    sctps->sctps_netstack->netstack_ip);
612 
613 				/*
614 				 * tsol_mlp_addr_type returns the possibilities
615 				 * for the selected address.  Since all local
616 				 * addresses are either private or shared, the
617 				 * return value mlptSingle means "local address
618 				 * not valid (interface not present)."
619 				 */
620 				if (addrtype == mlptSingle) {
621 					mutex_exit(&tbf->tf_lock);
622 					return (EADDRNOTAVAIL);
623 				}
624 				mlptype = tsol_mlp_port_type(zone, IPPROTO_SCTP,
625 				    port, addrtype);
626 				if (mlptype != mlptSingle) {
627 					if (secpolicy_net_bindmlp(connp->
628 					    conn_cred) != 0) {
629 						mutex_exit(&tbf->tf_lock);
630 						return (EACCES);
631 					}
632 					/*
633 					 * If we're binding a shared MLP, then
634 					 * make sure that this zone is the one
635 					 * that owns that MLP.  Shared MLPs can
636 					 * be owned by at most one zone.
637 					 *
638 					 * No need to handle exclusive-stack
639 					 * zones since ALL_ZONES only applies
640 					 * to the shared stack.
641 					 */
642 
643 					if (mlptype == mlptShared &&
644 					    addrtype == mlptShared &&
645 					    connp->conn_zoneid !=
646 					    tsol_mlp_findzone(IPPROTO_SCTP,
647 					    lport)) {
648 						mutex_exit(&tbf->tf_lock);
649 						return (EACCES);
650 					}
651 					connp->conn_mlp_type = mlptype;
652 				}
653 			}
654 			/*
655 			 * This port is ours. Insert in fanout and mark as
656 			 * bound to prevent others from getting the port
657 			 * number.
658 			 */
659 			sctp->sctp_state = SCTPS_BOUND;
660 			connp->conn_lport = lport;
661 
662 			ASSERT(&sctps->sctps_bind_fanout[
663 			    SCTP_BIND_HASH(port)] == tbf);
664 			sctp_bind_hash_insert(tbf, sctp, 1);
665 
666 			mutex_exit(&tbf->tf_lock);
667 
668 			/*
669 			 * We don't want sctp_next_port_to_try to "inherit"
670 			 * a port number supplied by the user in a bind.
671 			 *
672 			 * This is the only place where sctp_next_port_to_try
673 			 * is updated. After the update, it may or may not
674 			 * be in the valid range.
675 			 */
676 			if (user_specified == 0)
677 				sctps->sctps_next_port_to_try = port + 1;
678 
679 			*allocated_port = port;
680 
681 			return (0);
682 		}
683 
684 		if ((count == 0) && (user_specified)) {
685 			/*
686 			 * We may have to return an anonymous port. So
687 			 * get one to start with.
688 			 */
689 			port = sctp_update_next_port(
690 			    sctps->sctps_next_port_to_try,
691 			    zone, sctps);
692 			user_specified = 0;
693 		} else {
694 			port = sctp_update_next_port(port + 1, zone, sctps);
695 		}
696 		if (port == 0)
697 			break;
698 
699 		/*
700 		 * Don't let this loop run forever in the case where
701 		 * all of the anonymous ports are in use.
702 		 */
703 	} while (++count < loopmax);
704 
705 	return (bind_to_req_port_only ? EADDRINUSE : EADDRNOTAVAIL);
706 }
707 
708 /*
709  * Don't let port fall into the privileged range.
710  * Since the extra privileged ports can be arbitrary we also
711  * ensure that we exclude those from consideration.
712  * sctp_g_epriv_ports is not sorted thus we loop over it until
713  * there are no changes.
714  *
715  * Note: No locks are held when inspecting sctp_g_*epriv_ports
716  * but instead the code relies on:
717  * - the fact that the address of the array and its size never changes
718  * - the atomic assignment of the elements of the array
719  */
720 in_port_t
721 sctp_update_next_port(in_port_t port, zone_t *zone, sctp_stack_t *sctps)
722 {
723 	int i;
724 	boolean_t restart = B_FALSE;
725 
726 retry:
727 	if (port < sctps->sctps_smallest_anon_port)
728 		port = sctps->sctps_smallest_anon_port;
729 
730 	if (port > sctps->sctps_largest_anon_port) {
731 		if (restart)
732 			return (0);
733 		restart = B_TRUE;
734 		port = sctps->sctps_smallest_anon_port;
735 	}
736 
737 	if (port < sctps->sctps_smallest_nonpriv_port)
738 		port = sctps->sctps_smallest_nonpriv_port;
739 
740 	for (i = 0; i < sctps->sctps_g_num_epriv_ports; i++) {
741 		if (port == sctps->sctps_g_epriv_ports[i]) {
742 			port++;
743 			/*
744 			 * Make sure whether the port is in the
745 			 * valid range.
746 			 *
747 			 * XXX Note that if sctp_g_epriv_ports contains
748 			 * all the anonymous ports this will be an
749 			 * infinite loop.
750 			 */
751 			goto retry;
752 		}
753 	}
754 
755 	if (is_system_labeled() &&
756 	    (i = tsol_next_port(zone, port, IPPROTO_SCTP, B_TRUE)) != 0) {
757 		port = i;
758 		goto retry;
759 	}
760 
761 	return (port);
762 }
763