xref: /titanic_44/usr/src/uts/common/inet/iptun/iptun.c (revision 160124a620427e5bf36392463283ed0a830a4f47)
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  * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 /*
27  * iptun - IP Tunneling Driver
28  *
29  * This module is a GLDv3 driver that implements virtual datalinks over IP
30  * (a.k.a, IP tunneling).  The datalinks are managed through a dld ioctl
31  * interface (see iptun_ctl.c), and registered with GLDv3 using
32  * mac_register().  It implements the logic for various forms of IP (IPv4 or
33  * IPv6) encapsulation within IP (IPv4 or IPv6) by interacting with the ip
34  * module below it.  Each virtual IP tunnel datalink has a conn_t associated
35  * with it representing the "outer" IP connection.
36  *
37  * The module implements the following locking semantics:
38  *
39  * Lookups and deletions in iptun_hash are synchronized using iptun_hash_lock.
40  * See comments above iptun_hash_lock for details.
41  *
42  * No locks are ever held while calling up to GLDv3.  The general architecture
43  * of GLDv3 requires this, as the mac perimeter (essentially a lock) for a
44  * given link will be held while making downcalls (iptun_m_*() callbacks).
45  * Because we need to hold locks while handling downcalls, holding these locks
46  * while issuing upcalls results in deadlock scenarios.  See the block comment
47  * above iptun_task_cb() for details on how we safely issue upcalls without
48  * holding any locks.
49  *
50  * The contents of each iptun_t is protected by an iptun_mutex which is held
51  * in iptun_enter() (called by iptun_enter_by_linkid()), and exited in
52  * iptun_exit().
53  *
54  * See comments in iptun_delete() and iptun_free() for details on how the
55  * iptun_t is deleted safely.
56  */
57 
58 #include <sys/types.h>
59 #include <sys/kmem.h>
60 #include <sys/errno.h>
61 #include <sys/modhash.h>
62 #include <sys/list.h>
63 #include <sys/strsun.h>
64 #include <sys/file.h>
65 #include <sys/systm.h>
66 #include <sys/tihdr.h>
67 #include <sys/param.h>
68 #include <sys/mac_provider.h>
69 #include <sys/mac_ipv4.h>
70 #include <sys/mac_ipv6.h>
71 #include <sys/mac_6to4.h>
72 #include <sys/tsol/tnet.h>
73 #include <sys/sunldi.h>
74 #include <netinet/in.h>
75 #include <netinet/ip6.h>
76 #include <inet/ip.h>
77 #include <inet/ip_ire.h>
78 #include <inet/ipsec_impl.h>
79 #include <sys/tsol/label.h>
80 #include <sys/tsol/tnet.h>
81 #include <inet/iptun.h>
82 #include "iptun_impl.h"
83 
84 /* Do the tunnel type and address family match? */
85 #define	IPTUN_ADDR_MATCH(iptun_type, family)				\
86 	((iptun_type == IPTUN_TYPE_IPV4 && family == AF_INET) ||	\
87 	(iptun_type == IPTUN_TYPE_IPV6 && family == AF_INET6) ||	\
88 	(iptun_type == IPTUN_TYPE_6TO4 && family == AF_INET))
89 
90 #define	IPTUN_HASH_KEY(key)	((mod_hash_key_t)(uintptr_t)(key))
91 
92 #define	IPTUN_MIN_IPV4_MTU	576		/* ip.h still uses 68 (!) */
93 #define	IPTUN_MIN_IPV6_MTU	IPV6_MIN_MTU
94 #define	IPTUN_MAX_IPV4_MTU	(IP_MAXPACKET - sizeof (ipha_t))
95 #define	IPTUN_MAX_IPV6_MTU	(IP_MAXPACKET - sizeof (ip6_t) -	\
96 				    sizeof (iptun_encaplim_t))
97 
98 #define	IPTUN_MIN_HOPLIMIT	1
99 #define	IPTUN_MAX_HOPLIMIT	UINT8_MAX
100 
101 #define	IPTUN_MIN_ENCAPLIMIT	0
102 #define	IPTUN_MAX_ENCAPLIMIT	UINT8_MAX
103 
104 #define	IPTUN_IPSEC_REQ_MASK	(IPSEC_PREF_REQUIRED | IPSEC_PREF_NEVER)
105 
106 static iptun_encaplim_t	iptun_encaplim_init = {
107 	{ IPPROTO_NONE, 0 },
108 	IP6OPT_TUNNEL_LIMIT,
109 	1,
110 	IPTUN_DEFAULT_ENCAPLIMIT,	/* filled in with actual value later */
111 	IP6OPT_PADN,
112 	1,
113 	0
114 };
115 
116 /*
117  * Table containing per-iptun-type information.
118  * Since IPv6 can run over all of these we have the IPv6 min as the min MTU.
119  */
120 static iptun_typeinfo_t	iptun_type_table[] = {
121 	{ IPTUN_TYPE_IPV4, MAC_PLUGIN_IDENT_IPV4, IPV4_VERSION,
122 	    IPTUN_MIN_IPV6_MTU,	IPTUN_MAX_IPV4_MTU,	B_TRUE },
123 	{ IPTUN_TYPE_IPV6, MAC_PLUGIN_IDENT_IPV6, IPV6_VERSION,
124 	    IPTUN_MIN_IPV6_MTU,	IPTUN_MAX_IPV6_MTU,	B_TRUE },
125 	{ IPTUN_TYPE_6TO4, MAC_PLUGIN_IDENT_6TO4, IPV4_VERSION,
126 	    IPTUN_MIN_IPV6_MTU,	IPTUN_MAX_IPV4_MTU,	B_FALSE },
127 	{ IPTUN_TYPE_UNKNOWN, NULL, 0, 0, 0, B_FALSE }
128 };
129 
130 /*
131  * iptun_hash is an iptun_t lookup table by link ID protected by
132  * iptun_hash_lock.  While the hash table's integrity is maintained via
133  * internal locking in the mod_hash_*() functions, we need additional locking
134  * so that an iptun_t cannot be deleted after a hash lookup has returned an
135  * iptun_t and before iptun_lock has been entered.  As such, we use
136  * iptun_hash_lock when doing lookups and removals from iptun_hash.
137  */
138 mod_hash_t	*iptun_hash;
139 static kmutex_t	iptun_hash_lock;
140 
141 static uint_t	iptun_tunnelcount;	/* total for all stacks */
142 kmem_cache_t	*iptun_cache;
143 ddi_taskq_t 	*iptun_taskq;
144 
145 typedef enum {
146 	IPTUN_TASK_MTU_UPDATE,	/* tell mac about new tunnel link MTU */
147 	IPTUN_TASK_LADDR_UPDATE, /* tell mac about new local address */
148 	IPTUN_TASK_RADDR_UPDATE, /* tell mac about new remote address */
149 	IPTUN_TASK_LINK_UPDATE,	/* tell mac about new link state */
150 	IPTUN_TASK_PDATA_UPDATE	/* tell mac about updated plugin data */
151 } iptun_task_t;
152 
153 typedef struct iptun_task_data_s {
154 	iptun_task_t	itd_task;
155 	datalink_id_t	itd_linkid;
156 } iptun_task_data_t;
157 
158 static void iptun_task_dispatch(iptun_t *, iptun_task_t);
159 static int iptun_enter(iptun_t *);
160 static void iptun_exit(iptun_t *);
161 static void iptun_headergen(iptun_t *, boolean_t);
162 static void iptun_drop_pkt(mblk_t *, uint64_t *);
163 static void iptun_input(void *, mblk_t *, void *, ip_recv_attr_t *);
164 static void iptun_input_icmp(void *, mblk_t *, void *, ip_recv_attr_t *);
165 static void iptun_output(iptun_t *, mblk_t *);
166 static uint32_t iptun_get_maxmtu(iptun_t *, ip_xmit_attr_t *, uint32_t);
167 static uint32_t iptun_update_mtu(iptun_t *, ip_xmit_attr_t *, uint32_t);
168 static uint32_t iptun_get_dst_pmtu(iptun_t *, ip_xmit_attr_t *);
169 static void iptun_update_dst_pmtu(iptun_t *, ip_xmit_attr_t *);
170 static int iptun_setladdr(iptun_t *, const struct sockaddr_storage *);
171 
172 static void iptun_output_6to4(iptun_t *, mblk_t *);
173 static void iptun_output_common(iptun_t *, ip_xmit_attr_t *, mblk_t *);
174 static boolean_t iptun_verifyicmp(conn_t *, void *, icmph_t *, icmp6_t *,
175     ip_recv_attr_t *);
176 
177 static void iptun_notify(void *, ip_xmit_attr_t *, ixa_notify_type_t,
178     ixa_notify_arg_t);
179 
180 static mac_callbacks_t iptun_m_callbacks;
181 
182 static int
183 iptun_m_getstat(void *arg, uint_t stat, uint64_t *val)
184 {
185 	iptun_t	*iptun = arg;
186 	int	err = 0;
187 
188 	switch (stat) {
189 	case MAC_STAT_IERRORS:
190 		*val = iptun->iptun_ierrors;
191 		break;
192 	case MAC_STAT_OERRORS:
193 		*val = iptun->iptun_oerrors;
194 		break;
195 	case MAC_STAT_RBYTES:
196 		*val = iptun->iptun_rbytes;
197 		break;
198 	case MAC_STAT_IPACKETS:
199 		*val = iptun->iptun_ipackets;
200 		break;
201 	case MAC_STAT_OBYTES:
202 		*val = iptun->iptun_obytes;
203 		break;
204 	case MAC_STAT_OPACKETS:
205 		*val = iptun->iptun_opackets;
206 		break;
207 	case MAC_STAT_NORCVBUF:
208 		*val = iptun->iptun_norcvbuf;
209 		break;
210 	case MAC_STAT_NOXMTBUF:
211 		*val = iptun->iptun_noxmtbuf;
212 		break;
213 	default:
214 		err = ENOTSUP;
215 	}
216 
217 	return (err);
218 }
219 
220 static int
221 iptun_m_start(void *arg)
222 {
223 	iptun_t	*iptun = arg;
224 	int	err;
225 
226 	if ((err = iptun_enter(iptun)) == 0) {
227 		iptun->iptun_flags |= IPTUN_MAC_STARTED;
228 		iptun_task_dispatch(iptun, IPTUN_TASK_LINK_UPDATE);
229 		iptun_exit(iptun);
230 	}
231 	return (err);
232 }
233 
234 static void
235 iptun_m_stop(void *arg)
236 {
237 	iptun_t *iptun = arg;
238 
239 	if (iptun_enter(iptun) == 0) {
240 		iptun->iptun_flags &= ~IPTUN_MAC_STARTED;
241 		iptun_task_dispatch(iptun, IPTUN_TASK_LINK_UPDATE);
242 		iptun_exit(iptun);
243 	}
244 }
245 
246 /*
247  * iptun_m_setpromisc() does nothing and always succeeds.  This is because a
248  * tunnel data-link only ever receives packets that are destined exclusively
249  * for the local address of the tunnel.
250  */
251 /* ARGSUSED */
252 static int
253 iptun_m_setpromisc(void *arg, boolean_t on)
254 {
255 	return (0);
256 }
257 
258 /* ARGSUSED */
259 static int
260 iptun_m_multicst(void *arg, boolean_t add, const uint8_t *addrp)
261 {
262 	return (ENOTSUP);
263 }
264 
265 /*
266  * iptun_m_unicst() sets the local address.
267  */
268 /* ARGSUSED */
269 static int
270 iptun_m_unicst(void *arg, const uint8_t *addrp)
271 {
272 	iptun_t			*iptun = arg;
273 	int			err;
274 	struct sockaddr_storage	ss;
275 	struct sockaddr_in	*sin;
276 	struct sockaddr_in6	*sin6;
277 
278 	if ((err = iptun_enter(iptun)) == 0) {
279 		switch (iptun->iptun_typeinfo->iti_ipvers) {
280 		case IPV4_VERSION:
281 			sin = (struct sockaddr_in *)&ss;
282 			sin->sin_family = AF_INET;
283 			bcopy(addrp, &sin->sin_addr, sizeof (in_addr_t));
284 			break;
285 		case IPV6_VERSION:
286 			sin6 = (struct sockaddr_in6 *)&ss;
287 			sin6->sin6_family = AF_INET6;
288 			bcopy(addrp, &sin6->sin6_addr, sizeof (in6_addr_t));
289 			break;
290 		default:
291 			ASSERT(0);
292 		}
293 		err = iptun_setladdr(iptun, &ss);
294 		iptun_exit(iptun);
295 	}
296 	return (err);
297 }
298 
299 static mblk_t *
300 iptun_m_tx(void *arg, mblk_t *mpchain)
301 {
302 	mblk_t	*mp, *nmp;
303 	iptun_t	*iptun = arg;
304 
305 	if (!IS_IPTUN_RUNNING(iptun)) {
306 		iptun_drop_pkt(mpchain, &iptun->iptun_noxmtbuf);
307 		return (NULL);
308 	}
309 
310 	for (mp = mpchain; mp != NULL; mp = nmp) {
311 		nmp = mp->b_next;
312 		mp->b_next = NULL;
313 		iptun_output(iptun, mp);
314 	}
315 
316 	return (NULL);
317 }
318 
319 /* ARGSUSED */
320 static int
321 iptun_m_setprop(void *barg, const char *pr_name, mac_prop_id_t pr_num,
322     uint_t pr_valsize, const void *pr_val)
323 {
324 	iptun_t		*iptun = barg;
325 	uint32_t	value = *(uint32_t *)pr_val;
326 	int		err;
327 
328 	/*
329 	 * We need to enter this iptun_t since we'll be modifying the outer
330 	 * header.
331 	 */
332 	if ((err = iptun_enter(iptun)) != 0)
333 		return (err);
334 
335 	switch (pr_num) {
336 	case MAC_PROP_IPTUN_HOPLIMIT:
337 		if (value < IPTUN_MIN_HOPLIMIT || value > IPTUN_MAX_HOPLIMIT) {
338 			err = EINVAL;
339 			break;
340 		}
341 		if (value != iptun->iptun_hoplimit) {
342 			iptun->iptun_hoplimit = (uint8_t)value;
343 			iptun_headergen(iptun, B_TRUE);
344 		}
345 		break;
346 	case MAC_PROP_IPTUN_ENCAPLIMIT:
347 		if (iptun->iptun_typeinfo->iti_type != IPTUN_TYPE_IPV6 ||
348 		    value > IPTUN_MAX_ENCAPLIMIT) {
349 			err = EINVAL;
350 			break;
351 		}
352 		if (value != iptun->iptun_encaplimit) {
353 			iptun->iptun_encaplimit = (uint8_t)value;
354 			iptun_headergen(iptun, B_TRUE);
355 		}
356 		break;
357 	case MAC_PROP_MTU: {
358 		uint32_t maxmtu = iptun_get_maxmtu(iptun, NULL, 0);
359 
360 		if (value < iptun->iptun_typeinfo->iti_minmtu ||
361 		    value > maxmtu) {
362 			err = EINVAL;
363 			break;
364 		}
365 		iptun->iptun_flags |= IPTUN_FIXED_MTU;
366 		if (value != iptun->iptun_mtu) {
367 			iptun->iptun_mtu = value;
368 			iptun_task_dispatch(iptun, IPTUN_TASK_MTU_UPDATE);
369 		}
370 		break;
371 	}
372 	default:
373 		err = EINVAL;
374 	}
375 	iptun_exit(iptun);
376 	return (err);
377 }
378 
379 /* ARGSUSED */
380 static int
381 iptun_m_getprop(void *barg, const char *pr_name, mac_prop_id_t pr_num,
382     uint_t pr_valsize, void *pr_val)
383 {
384 	iptun_t			*iptun = barg;
385 	int			err;
386 
387 	if ((err = iptun_enter(iptun)) != 0)
388 		return (err);
389 
390 	switch (pr_num) {
391 	case MAC_PROP_IPTUN_HOPLIMIT:
392 		ASSERT(pr_valsize >= sizeof (uint32_t));
393 		*(uint32_t *)pr_val = iptun->iptun_hoplimit;
394 		break;
395 
396 	case MAC_PROP_IPTUN_ENCAPLIMIT:
397 		*(uint32_t *)pr_val = iptun->iptun_encaplimit;
398 		break;
399 	default:
400 		err = ENOTSUP;
401 	}
402 done:
403 	iptun_exit(iptun);
404 	return (err);
405 }
406 
407 /* ARGSUSED */
408 static void
409 iptun_m_propinfo(void *barg, const char *pr_name, mac_prop_id_t pr_num,
410     mac_prop_info_handle_t prh)
411 {
412 	iptun_t			*iptun = barg;
413 
414 	switch (pr_num) {
415 	case MAC_PROP_IPTUN_HOPLIMIT:
416 		mac_prop_info_set_range_uint32(prh,
417 		    IPTUN_MIN_HOPLIMIT, IPTUN_MAX_HOPLIMIT);
418 		mac_prop_info_set_default_uint32(prh, IPTUN_DEFAULT_HOPLIMIT);
419 		break;
420 
421 	case MAC_PROP_IPTUN_ENCAPLIMIT:
422 		if (iptun->iptun_typeinfo->iti_type != IPTUN_TYPE_IPV6)
423 			break;
424 		mac_prop_info_set_range_uint32(prh,
425 		    IPTUN_MIN_ENCAPLIMIT, IPTUN_MAX_ENCAPLIMIT);
426 		mac_prop_info_set_default_uint32(prh, IPTUN_DEFAULT_ENCAPLIMIT);
427 		break;
428 	case MAC_PROP_MTU:
429 		mac_prop_info_set_range_uint32(prh,
430 		    iptun->iptun_typeinfo->iti_minmtu,
431 		    iptun_get_maxmtu(iptun, NULL, 0));
432 		break;
433 	}
434 }
435 
436 uint_t
437 iptun_count(void)
438 {
439 	return (iptun_tunnelcount);
440 }
441 
442 /*
443  * Enter an iptun_t exclusively.  This is essentially just a mutex, but we
444  * don't allow iptun_enter() to succeed on a tunnel if it's in the process of
445  * being deleted.
446  */
447 static int
448 iptun_enter(iptun_t *iptun)
449 {
450 	mutex_enter(&iptun->iptun_lock);
451 	while (iptun->iptun_flags & IPTUN_DELETE_PENDING)
452 		cv_wait(&iptun->iptun_enter_cv, &iptun->iptun_lock);
453 	if (iptun->iptun_flags & IPTUN_CONDEMNED) {
454 		mutex_exit(&iptun->iptun_lock);
455 		return (ENOENT);
456 	}
457 	return (0);
458 }
459 
460 /*
461  * Exit the tunnel entered in iptun_enter().
462  */
463 static void
464 iptun_exit(iptun_t *iptun)
465 {
466 	mutex_exit(&iptun->iptun_lock);
467 }
468 
469 /*
470  * Enter the IP tunnel instance by datalink ID.
471  */
472 static int
473 iptun_enter_by_linkid(datalink_id_t linkid, iptun_t **iptun)
474 {
475 	int err;
476 
477 	mutex_enter(&iptun_hash_lock);
478 	if (mod_hash_find(iptun_hash, IPTUN_HASH_KEY(linkid),
479 	    (mod_hash_val_t *)iptun) == 0)
480 		err = iptun_enter(*iptun);
481 	else
482 		err = ENOENT;
483 	if (err != 0)
484 		*iptun = NULL;
485 	mutex_exit(&iptun_hash_lock);
486 	return (err);
487 }
488 
489 /*
490  * Handle tasks that were deferred through the iptun_taskq because they require
491  * calling up to the mac module, and we can't call up to the mac module while
492  * holding locks.
493  *
494  * This is tricky to get right without introducing race conditions and
495  * deadlocks with the mac module, as we cannot issue an upcall while in the
496  * iptun_t.  The reason is that upcalls may try and enter the mac perimeter,
497  * while iptun callbacks (such as iptun_m_setprop()) called from the mac
498  * module will already have the perimeter held, and will then try and enter
499  * the iptun_t.  You can see the lock ordering problem with this; this will
500  * deadlock.
501  *
502  * The safe way to do this is to enter the iptun_t in question and copy the
503  * information we need out of it so that we can exit it and know that the
504  * information being passed up to the upcalls won't be subject to modification
505  * by other threads.  The problem now is that we need to exit it prior to
506  * issuing the upcall, but once we do this, a thread could come along and
507  * delete the iptun_t and thus the mac handle required to issue the upcall.
508  * To prevent this, we set the IPTUN_UPCALL_PENDING flag prior to exiting the
509  * iptun_t.  This flag is the condition associated with iptun_upcall_cv, which
510  * iptun_delete() will cv_wait() on.  When the upcall completes, we clear
511  * IPTUN_UPCALL_PENDING and cv_signal() any potentially waiting
512  * iptun_delete().  We can thus still safely use iptun->iptun_mh after having
513  * exited the iptun_t.
514  */
515 static void
516 iptun_task_cb(void *arg)
517 {
518 	iptun_task_data_t	*itd = arg;
519 	iptun_task_t		task = itd->itd_task;
520 	datalink_id_t		linkid = itd->itd_linkid;
521 	iptun_t			*iptun;
522 	uint32_t		mtu;
523 	iptun_addr_t		addr;
524 	link_state_t		linkstate;
525 	size_t			header_size;
526 	iptun_header_t		header;
527 
528 	kmem_free(itd, sizeof (*itd));
529 
530 	/*
531 	 * Note that if the lookup fails, it's because the tunnel was deleted
532 	 * between the time the task was dispatched and now.  That isn't an
533 	 * error.
534 	 */
535 	if (iptun_enter_by_linkid(linkid, &iptun) != 0)
536 		return;
537 
538 	iptun->iptun_flags |= IPTUN_UPCALL_PENDING;
539 
540 	switch (task) {
541 	case IPTUN_TASK_MTU_UPDATE:
542 		mtu = iptun->iptun_mtu;
543 		break;
544 	case IPTUN_TASK_LADDR_UPDATE:
545 		addr = iptun->iptun_laddr;
546 		break;
547 	case IPTUN_TASK_RADDR_UPDATE:
548 		addr = iptun->iptun_raddr;
549 		break;
550 	case IPTUN_TASK_LINK_UPDATE:
551 		linkstate = IS_IPTUN_RUNNING(iptun) ?
552 		    LINK_STATE_UP : LINK_STATE_DOWN;
553 		break;
554 	case IPTUN_TASK_PDATA_UPDATE:
555 		header_size = iptun->iptun_header_size;
556 		header = iptun->iptun_header;
557 		break;
558 	default:
559 		ASSERT(0);
560 	}
561 
562 	iptun_exit(iptun);
563 
564 	switch (task) {
565 	case IPTUN_TASK_MTU_UPDATE:
566 		(void) mac_maxsdu_update(iptun->iptun_mh, mtu);
567 		break;
568 	case IPTUN_TASK_LADDR_UPDATE:
569 		mac_unicst_update(iptun->iptun_mh, (uint8_t *)&addr.ia_addr);
570 		break;
571 	case IPTUN_TASK_RADDR_UPDATE:
572 		mac_dst_update(iptun->iptun_mh, (uint8_t *)&addr.ia_addr);
573 		break;
574 	case IPTUN_TASK_LINK_UPDATE:
575 		mac_link_update(iptun->iptun_mh, linkstate);
576 		break;
577 	case IPTUN_TASK_PDATA_UPDATE:
578 		if (mac_pdata_update(iptun->iptun_mh,
579 		    header_size == 0 ? NULL : &header, header_size) != 0)
580 			atomic_inc_64(&iptun->iptun_taskq_fail);
581 		break;
582 	}
583 
584 	mutex_enter(&iptun->iptun_lock);
585 	iptun->iptun_flags &= ~IPTUN_UPCALL_PENDING;
586 	cv_signal(&iptun->iptun_upcall_cv);
587 	mutex_exit(&iptun->iptun_lock);
588 }
589 
590 static void
591 iptun_task_dispatch(iptun_t *iptun, iptun_task_t iptun_task)
592 {
593 	iptun_task_data_t *itd;
594 
595 	itd = kmem_alloc(sizeof (*itd), KM_NOSLEEP);
596 	if (itd == NULL) {
597 		atomic_inc_64(&iptun->iptun_taskq_fail);
598 		return;
599 	}
600 	itd->itd_task = iptun_task;
601 	itd->itd_linkid = iptun->iptun_linkid;
602 	if (ddi_taskq_dispatch(iptun_taskq, iptun_task_cb, itd, DDI_NOSLEEP)) {
603 		atomic_inc_64(&iptun->iptun_taskq_fail);
604 		kmem_free(itd, sizeof (*itd));
605 	}
606 }
607 
608 /*
609  * Convert an iptun_addr_t to sockaddr_storage.
610  */
611 static void
612 iptun_getaddr(iptun_addr_t *iptun_addr, struct sockaddr_storage *ss)
613 {
614 	struct sockaddr_in	*sin;
615 	struct sockaddr_in6	*sin6;
616 
617 	bzero(ss, sizeof (*ss));
618 	switch (iptun_addr->ia_family) {
619 	case AF_INET:
620 		sin = (struct sockaddr_in *)ss;
621 		sin->sin_addr.s_addr = iptun_addr->ia_addr.iau_addr4;
622 		break;
623 	case AF_INET6:
624 		sin6 = (struct sockaddr_in6 *)ss;
625 		sin6->sin6_addr = iptun_addr->ia_addr.iau_addr6;
626 		break;
627 	default:
628 		ASSERT(0);
629 	}
630 	ss->ss_family = iptun_addr->ia_family;
631 }
632 
633 /*
634  * General purpose function to set an IP tunnel source or destination address.
635  */
636 static int
637 iptun_setaddr(iptun_type_t iptun_type, iptun_addr_t *iptun_addr,
638     const struct sockaddr_storage *ss)
639 {
640 	if (!IPTUN_ADDR_MATCH(iptun_type, ss->ss_family))
641 		return (EINVAL);
642 
643 	switch (ss->ss_family) {
644 	case AF_INET: {
645 		struct sockaddr_in *sin = (struct sockaddr_in *)ss;
646 
647 		if ((sin->sin_addr.s_addr == INADDR_ANY) ||
648 		    (sin->sin_addr.s_addr == INADDR_BROADCAST) ||
649 		    CLASSD(sin->sin_addr.s_addr)) {
650 			return (EADDRNOTAVAIL);
651 		}
652 		iptun_addr->ia_addr.iau_addr4 = sin->sin_addr.s_addr;
653 		break;
654 	}
655 	case AF_INET6: {
656 		struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)ss;
657 
658 		if (IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr) ||
659 		    IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr) ||
660 		    IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) {
661 			return (EADDRNOTAVAIL);
662 		}
663 		iptun_addr->ia_addr.iau_addr6 = sin6->sin6_addr;
664 		break;
665 	}
666 	default:
667 		return (EAFNOSUPPORT);
668 	}
669 	iptun_addr->ia_family = ss->ss_family;
670 	return (0);
671 }
672 
673 static int
674 iptun_setladdr(iptun_t *iptun, const struct sockaddr_storage *laddr)
675 {
676 	return (iptun_setaddr(iptun->iptun_typeinfo->iti_type,
677 	    &iptun->iptun_laddr, laddr));
678 }
679 
680 static int
681 iptun_setraddr(iptun_t *iptun, const struct sockaddr_storage *raddr)
682 {
683 	if (!(iptun->iptun_typeinfo->iti_hasraddr))
684 		return (EINVAL);
685 	return (iptun_setaddr(iptun->iptun_typeinfo->iti_type,
686 	    &iptun->iptun_raddr, raddr));
687 }
688 
689 static boolean_t
690 iptun_canbind(iptun_t *iptun)
691 {
692 	/*
693 	 * A tunnel may bind when its source address has been set, and if its
694 	 * tunnel type requires one, also its destination address.
695 	 */
696 	return ((iptun->iptun_flags & IPTUN_LADDR) &&
697 	    ((iptun->iptun_flags & IPTUN_RADDR) ||
698 	    !(iptun->iptun_typeinfo->iti_hasraddr)));
699 }
700 
701 /*
702  * Verify that the local address is valid, and insert in the fanout
703  */
704 static int
705 iptun_bind(iptun_t *iptun)
706 {
707 	conn_t			*connp = iptun->iptun_connp;
708 	int			error = 0;
709 	ip_xmit_attr_t		*ixa;
710 	iulp_t			uinfo;
711 	ip_stack_t		*ipst = connp->conn_netstack->netstack_ip;
712 
713 	/* Get an exclusive ixa for this thread, and replace conn_ixa */
714 	ixa = conn_get_ixa(connp, B_TRUE);
715 	if (ixa == NULL)
716 		return (ENOMEM);
717 	ASSERT(ixa->ixa_refcnt >= 2);
718 	ASSERT(ixa == connp->conn_ixa);
719 
720 	/* We create PMTU state including for 6to4 */
721 	ixa->ixa_flags |= IXAF_PMTU_DISCOVERY;
722 
723 	ASSERT(iptun_canbind(iptun));
724 
725 	mutex_enter(&connp->conn_lock);
726 	/*
727 	 * Note that conn_proto can't be set since the upper protocol
728 	 * can be both 41 and 4 when IPv6 and IPv4 are over the same tunnel.
729 	 * ipcl_iptun_classify doesn't use conn_proto.
730 	 */
731 	connp->conn_ipversion = iptun->iptun_typeinfo->iti_ipvers;
732 
733 	switch (iptun->iptun_typeinfo->iti_type) {
734 	case IPTUN_TYPE_IPV4:
735 		IN6_IPADDR_TO_V4MAPPED(iptun->iptun_laddr4,
736 		    &connp->conn_laddr_v6);
737 		IN6_IPADDR_TO_V4MAPPED(iptun->iptun_raddr4,
738 		    &connp->conn_faddr_v6);
739 		ixa->ixa_flags |= IXAF_IS_IPV4;
740 		if (ip_laddr_verify_v4(iptun->iptun_laddr4, IPCL_ZONEID(connp),
741 		    ipst, B_FALSE) != IPVL_UNICAST_UP) {
742 			mutex_exit(&connp->conn_lock);
743 			error = EADDRNOTAVAIL;
744 			goto done;
745 		}
746 		break;
747 	case IPTUN_TYPE_IPV6:
748 		connp->conn_laddr_v6 = iptun->iptun_laddr6;
749 		connp->conn_faddr_v6 = iptun->iptun_raddr6;
750 		ixa->ixa_flags &= ~IXAF_IS_IPV4;
751 		/* We use a zero scopeid for now */
752 		if (ip_laddr_verify_v6(&iptun->iptun_laddr6, IPCL_ZONEID(connp),
753 		    ipst, B_FALSE, 0) != IPVL_UNICAST_UP) {
754 			mutex_exit(&connp->conn_lock);
755 			error = EADDRNOTAVAIL;
756 			goto done;
757 		}
758 		break;
759 	case IPTUN_TYPE_6TO4:
760 		IN6_IPADDR_TO_V4MAPPED(iptun->iptun_laddr4,
761 		    &connp->conn_laddr_v6);
762 		IN6_IPADDR_TO_V4MAPPED(INADDR_ANY, &connp->conn_faddr_v6);
763 		ixa->ixa_flags |= IXAF_IS_IPV4;
764 		mutex_exit(&connp->conn_lock);
765 
766 		switch (ip_laddr_verify_v4(iptun->iptun_laddr4,
767 		    IPCL_ZONEID(connp), ipst, B_FALSE)) {
768 		case IPVL_UNICAST_UP:
769 		case IPVL_UNICAST_DOWN:
770 			break;
771 		default:
772 			error = EADDRNOTAVAIL;
773 			goto done;
774 		}
775 		goto insert;
776 	}
777 
778 	/* In case previous destination was multirt */
779 	ip_attr_newdst(ixa);
780 
781 	/*
782 	 * When we set a tunnel's destination address, we do not
783 	 * care if the destination is reachable.  Transient routing
784 	 * issues should not inhibit the creation of a tunnel
785 	 * interface, for example. Thus we pass B_FALSE here.
786 	 */
787 	connp->conn_saddr_v6 = connp->conn_laddr_v6;
788 	mutex_exit(&connp->conn_lock);
789 
790 	/* As long as the MTU is large we avoid fragmentation */
791 	ixa->ixa_flags |= IXAF_DONTFRAG | IXAF_PMTU_IPV4_DF;
792 
793 	/* We handle IPsec in iptun_output_common */
794 	error = ip_attr_connect(connp, ixa, &connp->conn_saddr_v6,
795 	    &connp->conn_faddr_v6, &connp->conn_faddr_v6, 0,
796 	    &connp->conn_saddr_v6, &uinfo, 0);
797 
798 	if (error != 0)
799 		goto done;
800 
801 	/* saddr shouldn't change since it was already set */
802 	ASSERT(IN6_ARE_ADDR_EQUAL(&connp->conn_laddr_v6,
803 	    &connp->conn_saddr_v6));
804 
805 	/* We set IXAF_VERIFY_PMTU to catch PMTU increases */
806 	ixa->ixa_flags |= IXAF_VERIFY_PMTU;
807 	ASSERT(uinfo.iulp_mtu != 0);
808 
809 	/*
810 	 * Allow setting new policies.
811 	 * The addresses/ports are already set, thus the IPsec policy calls
812 	 * can handle their passed-in conn's.
813 	 */
814 	connp->conn_policy_cached = B_FALSE;
815 
816 insert:
817 	error = ipcl_conn_insert(connp);
818 	if (error != 0)
819 		goto done;
820 
821 	/* Record this as the "last" send even though we haven't sent any */
822 	connp->conn_v6lastdst = connp->conn_faddr_v6;
823 
824 	iptun->iptun_flags |= IPTUN_BOUND;
825 	/*
826 	 * Now that we're bound with ip below us, this is a good
827 	 * time to initialize the destination path MTU and to
828 	 * re-calculate the tunnel's link MTU.
829 	 */
830 	(void) iptun_update_mtu(iptun, ixa, 0);
831 
832 	if (IS_IPTUN_RUNNING(iptun))
833 		iptun_task_dispatch(iptun, IPTUN_TASK_LINK_UPDATE);
834 
835 done:
836 	ixa_refrele(ixa);
837 	return (error);
838 }
839 
840 static void
841 iptun_unbind(iptun_t *iptun)
842 {
843 	ASSERT(iptun->iptun_flags & IPTUN_BOUND);
844 	ASSERT(mutex_owned(&iptun->iptun_lock) ||
845 	    (iptun->iptun_flags & IPTUN_CONDEMNED));
846 	ip_unbind(iptun->iptun_connp);
847 	iptun->iptun_flags &= ~IPTUN_BOUND;
848 	if (!(iptun->iptun_flags & IPTUN_CONDEMNED))
849 		iptun_task_dispatch(iptun, IPTUN_TASK_LINK_UPDATE);
850 }
851 
852 /*
853  * Re-generate the template data-link header for a given IP tunnel given the
854  * tunnel's current parameters.
855  */
856 static void
857 iptun_headergen(iptun_t *iptun, boolean_t update_mac)
858 {
859 	switch (iptun->iptun_typeinfo->iti_ipvers) {
860 	case IPV4_VERSION:
861 		/*
862 		 * We only need to use a custom IP header if the administrator
863 		 * has supplied a non-default hoplimit.
864 		 */
865 		if (iptun->iptun_hoplimit == IPTUN_DEFAULT_HOPLIMIT) {
866 			iptun->iptun_header_size = 0;
867 			break;
868 		}
869 		iptun->iptun_header_size = sizeof (ipha_t);
870 		iptun->iptun_header4.ipha_version_and_hdr_length =
871 		    IP_SIMPLE_HDR_VERSION;
872 		iptun->iptun_header4.ipha_fragment_offset_and_flags =
873 		    htons(IPH_DF);
874 		iptun->iptun_header4.ipha_ttl = iptun->iptun_hoplimit;
875 		break;
876 	case IPV6_VERSION: {
877 		ip6_t	*ip6hp = &iptun->iptun_header6.it6h_ip6h;
878 
879 		/*
880 		 * We only need to use a custom IPv6 header if either the
881 		 * administrator has supplied a non-default hoplimit, or we
882 		 * need to include an encapsulation limit option in the outer
883 		 * header.
884 		 */
885 		if (iptun->iptun_hoplimit == IPTUN_DEFAULT_HOPLIMIT &&
886 		    iptun->iptun_encaplimit == 0) {
887 			iptun->iptun_header_size = 0;
888 			break;
889 		}
890 
891 		(void) memset(ip6hp, 0, sizeof (*ip6hp));
892 		if (iptun->iptun_encaplimit == 0) {
893 			iptun->iptun_header_size = sizeof (ip6_t);
894 			ip6hp->ip6_nxt = IPPROTO_NONE;
895 		} else {
896 			iptun_encaplim_t	*iel;
897 
898 			iptun->iptun_header_size = sizeof (iptun_ipv6hdrs_t);
899 			/*
900 			 * The mac_ipv6 plugin requires ip6_plen to be in host
901 			 * byte order and reflect the extension headers
902 			 * present in the template.  The actual network byte
903 			 * order ip6_plen will be set on a per-packet basis on
904 			 * transmit.
905 			 */
906 			ip6hp->ip6_plen = sizeof (*iel);
907 			ip6hp->ip6_nxt = IPPROTO_DSTOPTS;
908 			iel = &iptun->iptun_header6.it6h_encaplim;
909 			*iel = iptun_encaplim_init;
910 			iel->iel_telopt.ip6ot_encap_limit =
911 			    iptun->iptun_encaplimit;
912 		}
913 
914 		ip6hp->ip6_hlim = iptun->iptun_hoplimit;
915 		break;
916 	}
917 	}
918 
919 	if (update_mac)
920 		iptun_task_dispatch(iptun, IPTUN_TASK_PDATA_UPDATE);
921 }
922 
923 /*
924  * Insert inbound and outbound IPv4 and IPv6 policy into the given policy
925  * head.
926  */
927 static boolean_t
928 iptun_insert_simple_policies(ipsec_policy_head_t *ph, ipsec_act_t *actp,
929     uint_t n, netstack_t *ns)
930 {
931 	int f = IPSEC_AF_V4;
932 
933 	if (!ipsec_polhead_insert(ph, actp, n, f, IPSEC_TYPE_INBOUND, ns) ||
934 	    !ipsec_polhead_insert(ph, actp, n, f, IPSEC_TYPE_OUTBOUND, ns))
935 		return (B_FALSE);
936 
937 	f = IPSEC_AF_V6;
938 	return (ipsec_polhead_insert(ph, actp, n, f, IPSEC_TYPE_INBOUND, ns) &&
939 	    ipsec_polhead_insert(ph, actp, n, f, IPSEC_TYPE_OUTBOUND, ns));
940 }
941 
942 /*
943  * Used to set IPsec policy when policy is set through the IPTUN_CREATE or
944  * IPTUN_MODIFY ioctls.
945  */
946 static int
947 iptun_set_sec_simple(iptun_t *iptun, const ipsec_req_t *ipsr)
948 {
949 	int		rc = 0;
950 	uint_t		nact;
951 	ipsec_act_t	*actp = NULL;
952 	boolean_t	clear_all, old_policy = B_FALSE;
953 	ipsec_tun_pol_t	*itp;
954 	char		name[MAXLINKNAMELEN];
955 	uint64_t	gen;
956 	netstack_t	*ns = iptun->iptun_ns;
957 
958 	/* Can't specify self-encap on a tunnel. */
959 	if (ipsr->ipsr_self_encap_req != 0)
960 		return (EINVAL);
961 
962 	/*
963 	 * If it's a "clear-all" entry, unset the security flags and resume
964 	 * normal cleartext (or inherit-from-global) policy.
965 	 */
966 	clear_all = ((ipsr->ipsr_ah_req & IPTUN_IPSEC_REQ_MASK) == 0 &&
967 	    (ipsr->ipsr_esp_req & IPTUN_IPSEC_REQ_MASK) == 0);
968 
969 	ASSERT(mutex_owned(&iptun->iptun_lock));
970 	itp = iptun->iptun_itp;
971 	if (itp == NULL) {
972 		if (clear_all)
973 			goto bail;
974 		if ((rc = dls_mgmt_get_linkinfo(iptun->iptun_linkid, name, NULL,
975 		    NULL, NULL)) != 0)
976 			goto bail;
977 		ASSERT(name[0] != '\0');
978 		if ((itp = create_tunnel_policy(name, &rc, &gen, ns)) == NULL)
979 			goto bail;
980 		iptun->iptun_itp = itp;
981 	}
982 
983 	/* Allocate the actvec now, before holding itp or polhead locks. */
984 	ipsec_actvec_from_req(ipsr, &actp, &nact, ns);
985 	if (actp == NULL) {
986 		rc = ENOMEM;
987 		goto bail;
988 	}
989 
990 	/*
991 	 * Just write on the active polhead.  Save the primary/secondary stuff
992 	 * for spdsock operations.
993 	 *
994 	 * Mutex because we need to write to the polhead AND flags atomically.
995 	 * Other threads will acquire the polhead lock as a reader if the
996 	 * (unprotected) flag is set.
997 	 */
998 	mutex_enter(&itp->itp_lock);
999 	if (itp->itp_flags & ITPF_P_TUNNEL) {
1000 		/* Oops, we lost a race.  Let's get out of here. */
1001 		rc = EBUSY;
1002 		goto mutex_bail;
1003 	}
1004 	old_policy = ((itp->itp_flags & ITPF_P_ACTIVE) != 0);
1005 
1006 	if (old_policy) {
1007 		ITPF_CLONE(itp->itp_flags);
1008 		rc = ipsec_copy_polhead(itp->itp_policy, itp->itp_inactive, ns);
1009 		if (rc != 0) {
1010 			/* inactive has already been cleared. */
1011 			itp->itp_flags &= ~ITPF_IFLAGS;
1012 			goto mutex_bail;
1013 		}
1014 		rw_enter(&itp->itp_policy->iph_lock, RW_WRITER);
1015 		ipsec_polhead_flush(itp->itp_policy, ns);
1016 	} else {
1017 		/* Else assume itp->itp_policy is already flushed. */
1018 		rw_enter(&itp->itp_policy->iph_lock, RW_WRITER);
1019 	}
1020 
1021 	if (clear_all) {
1022 		ASSERT(avl_numnodes(&itp->itp_policy->iph_rulebyid) == 0);
1023 		itp->itp_flags &= ~ITPF_PFLAGS;
1024 		rw_exit(&itp->itp_policy->iph_lock);
1025 		old_policy = B_FALSE;	/* Clear out the inactive one too. */
1026 		goto recover_bail;
1027 	}
1028 
1029 	if (iptun_insert_simple_policies(itp->itp_policy, actp, nact, ns)) {
1030 		rw_exit(&itp->itp_policy->iph_lock);
1031 		/*
1032 		 * Adjust MTU and make sure the DL side knows what's up.
1033 		 */
1034 		itp->itp_flags = ITPF_P_ACTIVE;
1035 		(void) iptun_update_mtu(iptun, NULL, 0);
1036 		old_policy = B_FALSE;	/* Blank out inactive - we succeeded */
1037 	} else {
1038 		rw_exit(&itp->itp_policy->iph_lock);
1039 		rc = ENOMEM;
1040 	}
1041 
1042 recover_bail:
1043 	if (old_policy) {
1044 		/* Recover policy in in active polhead. */
1045 		ipsec_swap_policy(itp->itp_policy, itp->itp_inactive, ns);
1046 		ITPF_SWAP(itp->itp_flags);
1047 	}
1048 
1049 	/* Clear policy in inactive polhead. */
1050 	itp->itp_flags &= ~ITPF_IFLAGS;
1051 	rw_enter(&itp->itp_inactive->iph_lock, RW_WRITER);
1052 	ipsec_polhead_flush(itp->itp_inactive, ns);
1053 	rw_exit(&itp->itp_inactive->iph_lock);
1054 
1055 mutex_bail:
1056 	mutex_exit(&itp->itp_lock);
1057 
1058 bail:
1059 	if (actp != NULL)
1060 		ipsec_actvec_free(actp, nact);
1061 
1062 	return (rc);
1063 }
1064 
1065 static iptun_typeinfo_t *
1066 iptun_gettypeinfo(iptun_type_t type)
1067 {
1068 	int i;
1069 
1070 	for (i = 0; iptun_type_table[i].iti_type != IPTUN_TYPE_UNKNOWN; i++) {
1071 		if (iptun_type_table[i].iti_type == type)
1072 			break;
1073 	}
1074 	return (&iptun_type_table[i]);
1075 }
1076 
1077 /*
1078  * Set the parameters included in ik on the tunnel iptun.  Parameters that can
1079  * only be set at creation time are set in iptun_create().
1080  */
1081 static int
1082 iptun_setparams(iptun_t *iptun, const iptun_kparams_t *ik)
1083 {
1084 	int		err = 0;
1085 	netstack_t	*ns = iptun->iptun_ns;
1086 	iptun_addr_t	orig_laddr, orig_raddr;
1087 	uint_t		orig_flags = iptun->iptun_flags;
1088 
1089 	if (ik->iptun_kparam_flags & IPTUN_KPARAM_LADDR) {
1090 		if (orig_flags & IPTUN_LADDR)
1091 			orig_laddr = iptun->iptun_laddr;
1092 		if ((err = iptun_setladdr(iptun, &ik->iptun_kparam_laddr)) != 0)
1093 			return (err);
1094 		iptun->iptun_flags |= IPTUN_LADDR;
1095 	}
1096 
1097 	if (ik->iptun_kparam_flags & IPTUN_KPARAM_RADDR) {
1098 		if (orig_flags & IPTUN_RADDR)
1099 			orig_raddr = iptun->iptun_raddr;
1100 		if ((err = iptun_setraddr(iptun, &ik->iptun_kparam_raddr)) != 0)
1101 			goto done;
1102 		iptun->iptun_flags |= IPTUN_RADDR;
1103 	}
1104 
1105 	if (ik->iptun_kparam_flags & IPTUN_KPARAM_SECINFO) {
1106 		/*
1107 		 * Set IPsec policy originating from the ifconfig(1M) command
1108 		 * line.  This is traditionally called "simple" policy because
1109 		 * the ipsec_req_t (iptun_kparam_secinfo) can only describe a
1110 		 * simple policy of "do ESP on everything" and/or "do AH on
1111 		 * everything" (as opposed to the rich policy that can be
1112 		 * defined with ipsecconf(1M)).
1113 		 */
1114 		if (iptun->iptun_typeinfo->iti_type == IPTUN_TYPE_6TO4) {
1115 			/*
1116 			 * Can't set security properties for automatic
1117 			 * tunnels.
1118 			 */
1119 			err = EINVAL;
1120 			goto done;
1121 		}
1122 
1123 		if (!ipsec_loaded(ns->netstack_ipsec)) {
1124 			/* If IPsec can be loaded, try and load it now. */
1125 			if (ipsec_failed(ns->netstack_ipsec)) {
1126 				err = EPROTONOSUPPORT;
1127 				goto done;
1128 			}
1129 			ipsec_loader_loadnow(ns->netstack_ipsec);
1130 			/*
1131 			 * ipsec_loader_loadnow() returns while IPsec is
1132 			 * loaded asynchronously.  While a method exists to
1133 			 * wait for IPsec to load (ipsec_loader_wait()), it
1134 			 * requires use of a STREAMS queue to do a qwait().
1135 			 * We're not in STREAMS context here, and so we can't
1136 			 * use it.  This is not a problem in practice because
1137 			 * in the vast majority of cases, key management and
1138 			 * global policy will have loaded before any tunnels
1139 			 * are plumbed, and so IPsec will already have been
1140 			 * loaded.
1141 			 */
1142 			err = EAGAIN;
1143 			goto done;
1144 		}
1145 
1146 		err = iptun_set_sec_simple(iptun, &ik->iptun_kparam_secinfo);
1147 		if (err == 0) {
1148 			iptun->iptun_flags |= IPTUN_SIMPLE_POLICY;
1149 			iptun->iptun_simple_policy = ik->iptun_kparam_secinfo;
1150 		}
1151 	}
1152 done:
1153 	if (err != 0) {
1154 		/* Restore original source and destination. */
1155 		if (ik->iptun_kparam_flags & IPTUN_KPARAM_LADDR &&
1156 		    (orig_flags & IPTUN_LADDR))
1157 			iptun->iptun_laddr = orig_laddr;
1158 		if ((ik->iptun_kparam_flags & IPTUN_KPARAM_RADDR) &&
1159 		    (orig_flags & IPTUN_RADDR))
1160 			iptun->iptun_raddr = orig_raddr;
1161 		iptun->iptun_flags = orig_flags;
1162 	}
1163 	return (err);
1164 }
1165 
1166 static int
1167 iptun_register(iptun_t *iptun)
1168 {
1169 	mac_register_t	*mac;
1170 	int		err;
1171 
1172 	ASSERT(!(iptun->iptun_flags & IPTUN_MAC_REGISTERED));
1173 
1174 	if ((mac = mac_alloc(MAC_VERSION)) == NULL)
1175 		return (EINVAL);
1176 
1177 	mac->m_type_ident = iptun->iptun_typeinfo->iti_ident;
1178 	mac->m_driver = iptun;
1179 	mac->m_dip = iptun_dip;
1180 	mac->m_instance = (uint_t)-1;
1181 	mac->m_src_addr = (uint8_t *)&iptun->iptun_laddr.ia_addr;
1182 	mac->m_dst_addr = iptun->iptun_typeinfo->iti_hasraddr ?
1183 	    (uint8_t *)&iptun->iptun_raddr.ia_addr : NULL;
1184 	mac->m_callbacks = &iptun_m_callbacks;
1185 	mac->m_min_sdu = iptun->iptun_typeinfo->iti_minmtu;
1186 	mac->m_max_sdu = iptun->iptun_mtu;
1187 	if (iptun->iptun_header_size != 0) {
1188 		mac->m_pdata = &iptun->iptun_header;
1189 		mac->m_pdata_size = iptun->iptun_header_size;
1190 	}
1191 	if ((err = mac_register(mac, &iptun->iptun_mh)) == 0)
1192 		iptun->iptun_flags |= IPTUN_MAC_REGISTERED;
1193 	mac_free(mac);
1194 	return (err);
1195 }
1196 
1197 static int
1198 iptun_unregister(iptun_t *iptun)
1199 {
1200 	int err;
1201 
1202 	ASSERT(iptun->iptun_flags & IPTUN_MAC_REGISTERED);
1203 	if ((err = mac_unregister(iptun->iptun_mh)) == 0)
1204 		iptun->iptun_flags &= ~IPTUN_MAC_REGISTERED;
1205 	return (err);
1206 }
1207 
1208 static conn_t *
1209 iptun_conn_create(iptun_t *iptun, netstack_t *ns, cred_t *credp)
1210 {
1211 	conn_t *connp;
1212 
1213 	if ((connp = ipcl_conn_create(IPCL_IPCCONN, KM_NOSLEEP, ns)) == NULL)
1214 		return (NULL);
1215 
1216 	connp->conn_flags |= IPCL_IPTUN;
1217 	connp->conn_iptun = iptun;
1218 	connp->conn_recv = iptun_input;
1219 	connp->conn_recvicmp = iptun_input_icmp;
1220 	connp->conn_verifyicmp = iptun_verifyicmp;
1221 
1222 	/*
1223 	 * Register iptun_notify to listen to capability changes detected by IP.
1224 	 * This upcall is made in the context of the call to conn_ip_output.
1225 	 */
1226 	connp->conn_ixa->ixa_notify = iptun_notify;
1227 	connp->conn_ixa->ixa_notify_cookie = iptun;
1228 
1229 	/*
1230 	 * For exclusive stacks we set conn_zoneid to GLOBAL_ZONEID as is done
1231 	 * for all other conn_t's.
1232 	 *
1233 	 * Note that there's an important distinction between iptun_zoneid and
1234 	 * conn_zoneid.  The conn_zoneid is set to GLOBAL_ZONEID in non-global
1235 	 * exclusive stack zones to make the ip module believe that the
1236 	 * non-global zone is actually a global zone.  Therefore, when
1237 	 * interacting with the ip module, we must always use conn_zoneid.
1238 	 */
1239 	connp->conn_zoneid = (ns->netstack_stackid == GLOBAL_NETSTACKID) ?
1240 	    crgetzoneid(credp) : GLOBAL_ZONEID;
1241 	connp->conn_cred = credp;
1242 	/* crfree() is done in ipcl_conn_destroy(), called by CONN_DEC_REF() */
1243 	crhold(connp->conn_cred);
1244 	connp->conn_cpid = NOPID;
1245 
1246 	/* conn_allzones can not be set this early, hence no IPCL_ZONEID */
1247 	connp->conn_ixa->ixa_zoneid = connp->conn_zoneid;
1248 	ASSERT(connp->conn_ref == 1);
1249 
1250 	/* Cache things in ixa without an extra refhold */
1251 	ASSERT(!(connp->conn_ixa->ixa_free_flags & IXA_FREE_CRED));
1252 	connp->conn_ixa->ixa_cred = connp->conn_cred;
1253 	connp->conn_ixa->ixa_cpid = connp->conn_cpid;
1254 	if (is_system_labeled())
1255 		connp->conn_ixa->ixa_tsl = crgetlabel(connp->conn_cred);
1256 
1257 	/*
1258 	 * Have conn_ip_output drop packets should our outer source
1259 	 * go invalid
1260 	 */
1261 	connp->conn_ixa->ixa_flags |= IXAF_VERIFY_SOURCE;
1262 
1263 	switch (iptun->iptun_typeinfo->iti_ipvers) {
1264 	case IPV4_VERSION:
1265 		connp->conn_family = AF_INET6;
1266 		break;
1267 	case IPV6_VERSION:
1268 		connp->conn_family = AF_INET;
1269 		break;
1270 	}
1271 	mutex_enter(&connp->conn_lock);
1272 	connp->conn_state_flags &= ~CONN_INCIPIENT;
1273 	mutex_exit(&connp->conn_lock);
1274 	return (connp);
1275 }
1276 
1277 static void
1278 iptun_conn_destroy(conn_t *connp)
1279 {
1280 	ip_quiesce_conn(connp);
1281 	connp->conn_iptun = NULL;
1282 	ASSERT(connp->conn_ref == 1);
1283 	CONN_DEC_REF(connp);
1284 }
1285 
1286 static iptun_t *
1287 iptun_alloc(void)
1288 {
1289 	iptun_t *iptun;
1290 
1291 	if ((iptun = kmem_cache_alloc(iptun_cache, KM_NOSLEEP)) != NULL) {
1292 		bzero(iptun, sizeof (*iptun));
1293 		atomic_inc_32(&iptun_tunnelcount);
1294 	}
1295 	return (iptun);
1296 }
1297 
1298 static void
1299 iptun_free(iptun_t *iptun)
1300 {
1301 	ASSERT(iptun->iptun_flags & IPTUN_CONDEMNED);
1302 
1303 	if (iptun->iptun_flags & IPTUN_HASH_INSERTED) {
1304 		iptun_stack_t	*iptuns = iptun->iptun_iptuns;
1305 
1306 		mutex_enter(&iptun_hash_lock);
1307 		VERIFY(mod_hash_remove(iptun_hash,
1308 		    IPTUN_HASH_KEY(iptun->iptun_linkid),
1309 		    (mod_hash_val_t *)&iptun) == 0);
1310 		mutex_exit(&iptun_hash_lock);
1311 		iptun->iptun_flags &= ~IPTUN_HASH_INSERTED;
1312 		mutex_enter(&iptuns->iptuns_lock);
1313 		list_remove(&iptuns->iptuns_iptunlist, iptun);
1314 		mutex_exit(&iptuns->iptuns_lock);
1315 	}
1316 
1317 	if (iptun->iptun_flags & IPTUN_BOUND)
1318 		iptun_unbind(iptun);
1319 
1320 	/*
1321 	 * After iptun_unregister(), there will be no threads executing a
1322 	 * downcall from the mac module, including in the tx datapath.
1323 	 */
1324 	if (iptun->iptun_flags & IPTUN_MAC_REGISTERED)
1325 		VERIFY(iptun_unregister(iptun) == 0);
1326 
1327 	if (iptun->iptun_itp != NULL) {
1328 		/*
1329 		 * Remove from the AVL tree, AND release the reference iptun_t
1330 		 * itself holds on the ITP.
1331 		 */
1332 		itp_unlink(iptun->iptun_itp, iptun->iptun_ns);
1333 		ITP_REFRELE(iptun->iptun_itp, iptun->iptun_ns);
1334 		iptun->iptun_itp = NULL;
1335 		iptun->iptun_flags &= ~IPTUN_SIMPLE_POLICY;
1336 	}
1337 
1338 	/*
1339 	 * After ipcl_conn_destroy(), there will be no threads executing an
1340 	 * upcall from ip (i.e., iptun_input()), and it is then safe to free
1341 	 * the iptun_t.
1342 	 */
1343 	if (iptun->iptun_connp != NULL) {
1344 		iptun_conn_destroy(iptun->iptun_connp);
1345 		iptun->iptun_connp = NULL;
1346 	}
1347 
1348 	kmem_cache_free(iptun_cache, iptun);
1349 	atomic_dec_32(&iptun_tunnelcount);
1350 }
1351 
1352 int
1353 iptun_create(iptun_kparams_t *ik, cred_t *credp)
1354 {
1355 	iptun_t		*iptun = NULL;
1356 	int		err = 0, mherr;
1357 	char		linkname[MAXLINKNAMELEN];
1358 	ipsec_tun_pol_t	*itp;
1359 	netstack_t	*ns = NULL;
1360 	iptun_stack_t	*iptuns;
1361 	datalink_id_t	tmpid;
1362 	zoneid_t	zoneid = crgetzoneid(credp);
1363 	boolean_t	link_created = B_FALSE;
1364 
1365 	/* The tunnel type is mandatory */
1366 	if (!(ik->iptun_kparam_flags & IPTUN_KPARAM_TYPE))
1367 		return (EINVAL);
1368 
1369 	/*
1370 	 * Is the linkid that the caller wishes to associate with this new
1371 	 * tunnel assigned to this zone?
1372 	 */
1373 	if (zone_check_datalink(&zoneid, ik->iptun_kparam_linkid) != 0) {
1374 		if (zoneid != GLOBAL_ZONEID)
1375 			return (EINVAL);
1376 	} else if (zoneid == GLOBAL_ZONEID) {
1377 		return (EINVAL);
1378 	}
1379 
1380 	/*
1381 	 * Make sure that we're not trying to create a tunnel that has already
1382 	 * been created.
1383 	 */
1384 	if (iptun_enter_by_linkid(ik->iptun_kparam_linkid, &iptun) == 0) {
1385 		iptun_exit(iptun);
1386 		iptun = NULL;
1387 		err = EEXIST;
1388 		goto done;
1389 	}
1390 
1391 	ns = netstack_find_by_cred(credp);
1392 	iptuns = ns->netstack_iptun;
1393 
1394 	if ((iptun = iptun_alloc()) == NULL) {
1395 		err = ENOMEM;
1396 		goto done;
1397 	}
1398 
1399 	iptun->iptun_linkid = ik->iptun_kparam_linkid;
1400 	iptun->iptun_zoneid = zoneid;
1401 	iptun->iptun_ns = ns;
1402 
1403 	iptun->iptun_typeinfo = iptun_gettypeinfo(ik->iptun_kparam_type);
1404 	if (iptun->iptun_typeinfo->iti_type == IPTUN_TYPE_UNKNOWN) {
1405 		err = EINVAL;
1406 		goto done;
1407 	}
1408 
1409 	if (ik->iptun_kparam_flags & IPTUN_KPARAM_IMPLICIT)
1410 		iptun->iptun_flags |= IPTUN_IMPLICIT;
1411 
1412 	if ((err = iptun_setparams(iptun, ik)) != 0)
1413 		goto done;
1414 
1415 	iptun->iptun_hoplimit = IPTUN_DEFAULT_HOPLIMIT;
1416 	if (iptun->iptun_typeinfo->iti_type == IPTUN_TYPE_IPV6)
1417 		iptun->iptun_encaplimit = IPTUN_DEFAULT_ENCAPLIMIT;
1418 
1419 	iptun_headergen(iptun, B_FALSE);
1420 
1421 	iptun->iptun_connp = iptun_conn_create(iptun, ns, credp);
1422 	if (iptun->iptun_connp == NULL) {
1423 		err = ENOMEM;
1424 		goto done;
1425 	}
1426 
1427 	iptun->iptun_mtu = iptun->iptun_typeinfo->iti_maxmtu;
1428 	iptun->iptun_dpmtu = iptun->iptun_mtu;
1429 
1430 	/*
1431 	 * Find an ITP based on linkname.  If we have parms already set via
1432 	 * the iptun_setparams() call above, it may have created an ITP for
1433 	 * us.  We always try get_tunnel_policy() for DEBUG correctness
1434 	 * checks, and we may wish to refactor this to only check when
1435 	 * iptun_itp is NULL.
1436 	 */
1437 	if ((err = dls_mgmt_get_linkinfo(iptun->iptun_linkid, linkname, NULL,
1438 	    NULL, NULL)) != 0)
1439 		goto done;
1440 	if ((itp = get_tunnel_policy(linkname, ns)) != NULL)
1441 		iptun->iptun_itp = itp;
1442 
1443 	/*
1444 	 * See if we have the necessary IP addresses assigned to this tunnel
1445 	 * to try and bind them with ip underneath us.  If we're not ready to
1446 	 * bind yet, then we'll defer the bind operation until the addresses
1447 	 * are modified.
1448 	 */
1449 	if (iptun_canbind(iptun) && ((err = iptun_bind(iptun)) != 0))
1450 		goto done;
1451 
1452 	if ((err = iptun_register(iptun)) != 0)
1453 		goto done;
1454 
1455 	err = dls_devnet_create(iptun->iptun_mh, iptun->iptun_linkid,
1456 	    iptun->iptun_zoneid);
1457 	if (err != 0)
1458 		goto done;
1459 	link_created = B_TRUE;
1460 
1461 	/*
1462 	 * We hash by link-id as that is the key used by all other iptun
1463 	 * interfaces (modify, delete, etc.).
1464 	 */
1465 	if ((mherr = mod_hash_insert(iptun_hash,
1466 	    IPTUN_HASH_KEY(iptun->iptun_linkid), (mod_hash_val_t)iptun)) == 0) {
1467 		mutex_enter(&iptuns->iptuns_lock);
1468 		list_insert_head(&iptuns->iptuns_iptunlist, iptun);
1469 		mutex_exit(&iptuns->iptuns_lock);
1470 		iptun->iptun_flags |= IPTUN_HASH_INSERTED;
1471 	} else if (mherr == MH_ERR_NOMEM) {
1472 		err = ENOMEM;
1473 	} else if (mherr == MH_ERR_DUPLICATE) {
1474 		err = EEXIST;
1475 	} else {
1476 		err = EINVAL;
1477 	}
1478 
1479 done:
1480 	if (iptun == NULL && ns != NULL)
1481 		netstack_rele(ns);
1482 	if (err != 0 && iptun != NULL) {
1483 		if (link_created) {
1484 			(void) dls_devnet_destroy(iptun->iptun_mh, &tmpid,
1485 			    B_TRUE);
1486 		}
1487 		iptun->iptun_flags |= IPTUN_CONDEMNED;
1488 		iptun_free(iptun);
1489 	}
1490 	return (err);
1491 }
1492 
1493 int
1494 iptun_delete(datalink_id_t linkid, cred_t *credp)
1495 {
1496 	int	err;
1497 	iptun_t	*iptun = NULL;
1498 
1499 	if ((err = iptun_enter_by_linkid(linkid, &iptun)) != 0)
1500 		return (err);
1501 
1502 	/* One cannot delete a tunnel that belongs to another zone. */
1503 	if (iptun->iptun_zoneid != crgetzoneid(credp)) {
1504 		iptun_exit(iptun);
1505 		return (EACCES);
1506 	}
1507 
1508 	/*
1509 	 * We need to exit iptun in order to issue calls up the stack such as
1510 	 * dls_devnet_destroy().  If we call up while still in iptun, deadlock
1511 	 * with calls coming down the stack is possible.  We prevent other
1512 	 * threads from entering this iptun after we've exited it by setting
1513 	 * the IPTUN_DELETE_PENDING flag.  This will cause callers of
1514 	 * iptun_enter() to block waiting on iptun_enter_cv.  The assumption
1515 	 * here is that the functions we're calling while IPTUN_DELETE_PENDING
1516 	 * is set dont resuult in an iptun_enter() call, as that would result
1517 	 * in deadlock.
1518 	 */
1519 	iptun->iptun_flags |= IPTUN_DELETE_PENDING;
1520 
1521 	/* Wait for any pending upcall to the mac module to complete. */
1522 	while (iptun->iptun_flags & IPTUN_UPCALL_PENDING)
1523 		cv_wait(&iptun->iptun_upcall_cv, &iptun->iptun_lock);
1524 
1525 	iptun_exit(iptun);
1526 
1527 	if ((err = dls_devnet_destroy(iptun->iptun_mh, &linkid, B_TRUE)) == 0) {
1528 		/*
1529 		 * mac_disable() will fail with EBUSY if there are references
1530 		 * to the iptun MAC.  If there are none, then mac_disable()
1531 		 * will assure that none can be acquired until the MAC is
1532 		 * unregistered.
1533 		 *
1534 		 * XXX CR 6791335 prevents us from calling mac_disable() prior
1535 		 * to dls_devnet_destroy(), so we unfortunately need to
1536 		 * attempt to re-create the devnet node if mac_disable()
1537 		 * fails.
1538 		 */
1539 		if ((err = mac_disable(iptun->iptun_mh)) != 0) {
1540 			(void) dls_devnet_create(iptun->iptun_mh, linkid,
1541 			    iptun->iptun_zoneid);
1542 		}
1543 	}
1544 
1545 	/*
1546 	 * Now that we know the fate of this iptun_t, we need to clear
1547 	 * IPTUN_DELETE_PENDING, and set IPTUN_CONDEMNED if the iptun_t is
1548 	 * slated to be freed.  Either way, we need to signal the threads
1549 	 * waiting in iptun_enter() so that they can either fail if
1550 	 * IPTUN_CONDEMNED is set, or continue if it's not.
1551 	 */
1552 	mutex_enter(&iptun->iptun_lock);
1553 	iptun->iptun_flags &= ~IPTUN_DELETE_PENDING;
1554 	if (err == 0)
1555 		iptun->iptun_flags |= IPTUN_CONDEMNED;
1556 	cv_broadcast(&iptun->iptun_enter_cv);
1557 	mutex_exit(&iptun->iptun_lock);
1558 
1559 	/*
1560 	 * Note that there is no danger in calling iptun_free() after having
1561 	 * dropped the iptun_lock since callers of iptun_enter() at this point
1562 	 * are doing so from iptun_enter_by_linkid() (mac_disable() got rid of
1563 	 * threads entering from mac callbacks which call iptun_enter()
1564 	 * directly) which holds iptun_hash_lock, and iptun_free() grabs this
1565 	 * lock in order to remove the iptun_t from the hash table.
1566 	 */
1567 	if (err == 0)
1568 		iptun_free(iptun);
1569 
1570 	return (err);
1571 }
1572 
1573 int
1574 iptun_modify(const iptun_kparams_t *ik, cred_t *credp)
1575 {
1576 	iptun_t		*iptun;
1577 	boolean_t	laddr_change = B_FALSE, raddr_change = B_FALSE;
1578 	int		err;
1579 
1580 	if ((err = iptun_enter_by_linkid(ik->iptun_kparam_linkid, &iptun)) != 0)
1581 		return (err);
1582 
1583 	/* One cannot modify a tunnel that belongs to another zone. */
1584 	if (iptun->iptun_zoneid != crgetzoneid(credp)) {
1585 		err = EACCES;
1586 		goto done;
1587 	}
1588 
1589 	/* The tunnel type cannot be changed */
1590 	if (ik->iptun_kparam_flags & IPTUN_KPARAM_TYPE) {
1591 		err = EINVAL;
1592 		goto done;
1593 	}
1594 
1595 	if ((err = iptun_setparams(iptun, ik)) != 0)
1596 		goto done;
1597 	iptun_headergen(iptun, B_FALSE);
1598 
1599 	/*
1600 	 * If any of the tunnel's addresses has been modified and the tunnel
1601 	 * has the necessary addresses assigned to it, we need to try to bind
1602 	 * with ip underneath us.  If we're not ready to bind yet, then we'll
1603 	 * try again when the addresses are modified later.
1604 	 */
1605 	laddr_change = (ik->iptun_kparam_flags & IPTUN_KPARAM_LADDR);
1606 	raddr_change = (ik->iptun_kparam_flags & IPTUN_KPARAM_RADDR);
1607 	if (laddr_change || raddr_change) {
1608 		if (iptun->iptun_flags & IPTUN_BOUND)
1609 			iptun_unbind(iptun);
1610 		if (iptun_canbind(iptun) && (err = iptun_bind(iptun)) != 0) {
1611 			if (laddr_change)
1612 				iptun->iptun_flags &= ~IPTUN_LADDR;
1613 			if (raddr_change)
1614 				iptun->iptun_flags &= ~IPTUN_RADDR;
1615 			goto done;
1616 		}
1617 	}
1618 
1619 	if (laddr_change)
1620 		iptun_task_dispatch(iptun, IPTUN_TASK_LADDR_UPDATE);
1621 	if (raddr_change)
1622 		iptun_task_dispatch(iptun, IPTUN_TASK_RADDR_UPDATE);
1623 
1624 done:
1625 	iptun_exit(iptun);
1626 	return (err);
1627 }
1628 
1629 /* Given an IP tunnel's datalink id, fill in its parameters. */
1630 int
1631 iptun_info(iptun_kparams_t *ik, cred_t *credp)
1632 {
1633 	iptun_t	*iptun;
1634 	int	err;
1635 
1636 	/* Is the tunnel link visible from the caller's zone? */
1637 	if (!dls_devnet_islinkvisible(ik->iptun_kparam_linkid,
1638 	    crgetzoneid(credp)))
1639 		return (ENOENT);
1640 
1641 	if ((err = iptun_enter_by_linkid(ik->iptun_kparam_linkid, &iptun)) != 0)
1642 		return (err);
1643 
1644 	bzero(ik, sizeof (iptun_kparams_t));
1645 
1646 	ik->iptun_kparam_linkid = iptun->iptun_linkid;
1647 	ik->iptun_kparam_type = iptun->iptun_typeinfo->iti_type;
1648 	ik->iptun_kparam_flags |= IPTUN_KPARAM_TYPE;
1649 
1650 	if (iptun->iptun_flags & IPTUN_LADDR) {
1651 		iptun_getaddr(&iptun->iptun_laddr, &ik->iptun_kparam_laddr);
1652 		ik->iptun_kparam_flags |= IPTUN_KPARAM_LADDR;
1653 	}
1654 	if (iptun->iptun_flags & IPTUN_RADDR) {
1655 		iptun_getaddr(&iptun->iptun_raddr, &ik->iptun_kparam_raddr);
1656 		ik->iptun_kparam_flags |= IPTUN_KPARAM_RADDR;
1657 	}
1658 
1659 	if (iptun->iptun_flags & IPTUN_IMPLICIT)
1660 		ik->iptun_kparam_flags |= IPTUN_KPARAM_IMPLICIT;
1661 
1662 	if (iptun->iptun_itp != NULL) {
1663 		mutex_enter(&iptun->iptun_itp->itp_lock);
1664 		if (iptun->iptun_itp->itp_flags & ITPF_P_ACTIVE) {
1665 			ik->iptun_kparam_flags |= IPTUN_KPARAM_IPSECPOL;
1666 			if (iptun->iptun_flags & IPTUN_SIMPLE_POLICY) {
1667 				ik->iptun_kparam_flags |= IPTUN_KPARAM_SECINFO;
1668 				ik->iptun_kparam_secinfo =
1669 				    iptun->iptun_simple_policy;
1670 			}
1671 		}
1672 		mutex_exit(&iptun->iptun_itp->itp_lock);
1673 	}
1674 
1675 done:
1676 	iptun_exit(iptun);
1677 	return (err);
1678 }
1679 
1680 int
1681 iptun_set_6to4relay(netstack_t *ns, ipaddr_t relay_addr)
1682 {
1683 	if (relay_addr == INADDR_BROADCAST || CLASSD(relay_addr))
1684 		return (EADDRNOTAVAIL);
1685 	ns->netstack_iptun->iptuns_relay_rtr_addr = relay_addr;
1686 	return (0);
1687 }
1688 
1689 void
1690 iptun_get_6to4relay(netstack_t *ns, ipaddr_t *relay_addr)
1691 {
1692 	*relay_addr = ns->netstack_iptun->iptuns_relay_rtr_addr;
1693 }
1694 
1695 void
1696 iptun_set_policy(datalink_id_t linkid, ipsec_tun_pol_t *itp)
1697 {
1698 	iptun_t	*iptun;
1699 
1700 	if (iptun_enter_by_linkid(linkid, &iptun) != 0)
1701 		return;
1702 	if (iptun->iptun_itp != itp) {
1703 		ASSERT(iptun->iptun_itp == NULL);
1704 		ITP_REFHOLD(itp);
1705 		iptun->iptun_itp = itp;
1706 	}
1707 	/*
1708 	 * IPsec policy means IPsec overhead, which means lower MTU.
1709 	 * Refresh the MTU for this tunnel.
1710 	 */
1711 	(void) iptun_update_mtu(iptun, NULL, 0);
1712 	iptun_exit(iptun);
1713 }
1714 
1715 /*
1716  * Obtain the path MTU to the tunnel destination.
1717  * Can return zero in some cases.
1718  */
1719 static uint32_t
1720 iptun_get_dst_pmtu(iptun_t *iptun, ip_xmit_attr_t *ixa)
1721 {
1722 	uint32_t	pmtu = 0;
1723 	conn_t		*connp = iptun->iptun_connp;
1724 	boolean_t	need_rele = B_FALSE;
1725 
1726 	/*
1727 	 * We only obtain the pmtu for tunnels that have a remote tunnel
1728 	 * address.
1729 	 */
1730 	if (!(iptun->iptun_flags & IPTUN_RADDR))
1731 		return (0);
1732 
1733 	if (ixa == NULL) {
1734 		ixa = conn_get_ixa(connp, B_FALSE);
1735 		if (ixa == NULL)
1736 			return (0);
1737 		need_rele = B_TRUE;
1738 	}
1739 	/*
1740 	 * Guard against ICMP errors before we have sent, as well as against
1741 	 * and a thread which held conn_ixa.
1742 	 */
1743 	if (ixa->ixa_ire != NULL) {
1744 		pmtu = ip_get_pmtu(ixa);
1745 
1746 		/*
1747 		 * For both IPv4 and IPv6 we can have indication that the outer
1748 		 * header needs fragmentation.
1749 		 */
1750 		if (ixa->ixa_flags & IXAF_PMTU_TOO_SMALL) {
1751 			/* Must allow fragmentation in ip_output */
1752 			ixa->ixa_flags &= ~IXAF_DONTFRAG;
1753 		} else if (iptun->iptun_typeinfo->iti_type != IPTUN_TYPE_6TO4) {
1754 			ixa->ixa_flags |= IXAF_DONTFRAG;
1755 		} else {
1756 			/* ip_get_pmtu might have set this - we don't want it */
1757 			ixa->ixa_flags &= ~IXAF_PMTU_IPV4_DF;
1758 		}
1759 	}
1760 
1761 	if (need_rele)
1762 		ixa_refrele(ixa);
1763 	return (pmtu);
1764 }
1765 
1766 /*
1767  * Update the ip_xmit_attr_t to capture the current lower path mtu as known
1768  * by ip.
1769  */
1770 static void
1771 iptun_update_dst_pmtu(iptun_t *iptun, ip_xmit_attr_t *ixa)
1772 {
1773 	uint32_t	pmtu;
1774 	conn_t		*connp = iptun->iptun_connp;
1775 	boolean_t	need_rele = B_FALSE;
1776 
1777 	/* IXAF_VERIFY_PMTU is not set if we don't have a fixed destination */
1778 	if (!(iptun->iptun_flags & IPTUN_RADDR))
1779 		return;
1780 
1781 	if (ixa == NULL) {
1782 		ixa = conn_get_ixa(connp, B_FALSE);
1783 		if (ixa == NULL)
1784 			return;
1785 		need_rele = B_TRUE;
1786 	}
1787 	/*
1788 	 * Guard against ICMP errors before we have sent, as well as against
1789 	 * and a thread which held conn_ixa.
1790 	 */
1791 	if (ixa->ixa_ire != NULL) {
1792 		pmtu = ip_get_pmtu(ixa);
1793 		/*
1794 		 * Update ixa_fragsize and ixa_pmtu.
1795 		 */
1796 		ixa->ixa_fragsize = ixa->ixa_pmtu = pmtu;
1797 
1798 		/*
1799 		 * For both IPv4 and IPv6 we can have indication that the outer
1800 		 * header needs fragmentation.
1801 		 */
1802 		if (ixa->ixa_flags & IXAF_PMTU_TOO_SMALL) {
1803 			/* Must allow fragmentation in ip_output */
1804 			ixa->ixa_flags &= ~IXAF_DONTFRAG;
1805 		} else if (iptun->iptun_typeinfo->iti_type != IPTUN_TYPE_6TO4) {
1806 			ixa->ixa_flags |= IXAF_DONTFRAG;
1807 		} else {
1808 			/* ip_get_pmtu might have set this - we don't want it */
1809 			ixa->ixa_flags &= ~IXAF_PMTU_IPV4_DF;
1810 		}
1811 	}
1812 
1813 	if (need_rele)
1814 		ixa_refrele(ixa);
1815 }
1816 
1817 /*
1818  * There is nothing that iptun can verify in addition to IP having
1819  * verified the IP addresses in the fanout.
1820  */
1821 /* ARGSUSED */
1822 static boolean_t
1823 iptun_verifyicmp(conn_t *connp, void *arg2, icmph_t *icmph, icmp6_t *icmp6,
1824     ip_recv_attr_t *ira)
1825 {
1826 	return (B_TRUE);
1827 }
1828 
1829 /*
1830  * Notify function registered with ip_xmit_attr_t.
1831  */
1832 static void
1833 iptun_notify(void *arg, ip_xmit_attr_t *ixa, ixa_notify_type_t ntype,
1834     ixa_notify_arg_t narg)
1835 {
1836 	iptun_t		*iptun = (iptun_t *)arg;
1837 
1838 	switch (ntype) {
1839 	case IXAN_PMTU:
1840 		(void) iptun_update_mtu(iptun, ixa, narg);
1841 		break;
1842 	}
1843 }
1844 
1845 /*
1846  * Returns the max of old_ovhd and the overhead associated with pol.
1847  */
1848 static uint32_t
1849 iptun_max_policy_overhead(ipsec_policy_t *pol, uint32_t old_ovhd)
1850 {
1851 	uint32_t new_ovhd = old_ovhd;
1852 
1853 	while (pol != NULL) {
1854 		new_ovhd = max(new_ovhd,
1855 		    ipsec_act_ovhd(&pol->ipsp_act->ipa_act));
1856 		pol = pol->ipsp_hash.hash_next;
1857 	}
1858 	return (new_ovhd);
1859 }
1860 
1861 static uint32_t
1862 iptun_get_ipsec_overhead(iptun_t *iptun)
1863 {
1864 	ipsec_policy_root_t	*ipr;
1865 	ipsec_policy_head_t	*iph;
1866 	ipsec_policy_t		*pol;
1867 	ipsec_selector_t	sel;
1868 	int			i;
1869 	uint32_t		ipsec_ovhd = 0;
1870 	ipsec_tun_pol_t		*itp = iptun->iptun_itp;
1871 	netstack_t		*ns = iptun->iptun_ns;
1872 
1873 	if (itp == NULL || !(itp->itp_flags & ITPF_P_ACTIVE)) {
1874 		/*
1875 		 * Consult global policy, just in case.  This will only work
1876 		 * if we have both source and destination addresses to work
1877 		 * with.
1878 		 */
1879 		if ((iptun->iptun_flags & (IPTUN_LADDR|IPTUN_RADDR)) !=
1880 		    (IPTUN_LADDR|IPTUN_RADDR))
1881 			return (0);
1882 
1883 		iph = ipsec_system_policy(ns);
1884 		bzero(&sel, sizeof (sel));
1885 		sel.ips_isv4 =
1886 		    (iptun->iptun_typeinfo->iti_ipvers == IPV4_VERSION);
1887 		switch (iptun->iptun_typeinfo->iti_ipvers) {
1888 		case IPV4_VERSION:
1889 			sel.ips_local_addr_v4 = iptun->iptun_laddr4;
1890 			sel.ips_remote_addr_v4 = iptun->iptun_raddr4;
1891 			break;
1892 		case IPV6_VERSION:
1893 			sel.ips_local_addr_v6 = iptun->iptun_laddr6;
1894 			sel.ips_remote_addr_v6 = iptun->iptun_raddr6;
1895 			break;
1896 		}
1897 		/* Check for both IPv4 and IPv6. */
1898 		sel.ips_protocol = IPPROTO_ENCAP;
1899 		pol = ipsec_find_policy_head(NULL, iph, IPSEC_TYPE_OUTBOUND,
1900 		    &sel);
1901 		if (pol != NULL) {
1902 			ipsec_ovhd = ipsec_act_ovhd(&pol->ipsp_act->ipa_act);
1903 			IPPOL_REFRELE(pol);
1904 		}
1905 		sel.ips_protocol = IPPROTO_IPV6;
1906 		pol = ipsec_find_policy_head(NULL, iph, IPSEC_TYPE_OUTBOUND,
1907 		    &sel);
1908 		if (pol != NULL) {
1909 			ipsec_ovhd = max(ipsec_ovhd,
1910 			    ipsec_act_ovhd(&pol->ipsp_act->ipa_act));
1911 			IPPOL_REFRELE(pol);
1912 		}
1913 		IPPH_REFRELE(iph, ns);
1914 	} else {
1915 		/*
1916 		 * Look through all of the possible IPsec actions for the
1917 		 * tunnel, and find the largest potential IPsec overhead.
1918 		 */
1919 		iph = itp->itp_policy;
1920 		rw_enter(&iph->iph_lock, RW_READER);
1921 		ipr = &(iph->iph_root[IPSEC_TYPE_OUTBOUND]);
1922 		ipsec_ovhd = iptun_max_policy_overhead(
1923 		    ipr->ipr_nonhash[IPSEC_AF_V4], 0);
1924 		ipsec_ovhd = iptun_max_policy_overhead(
1925 		    ipr->ipr_nonhash[IPSEC_AF_V6], ipsec_ovhd);
1926 		for (i = 0; i < ipr->ipr_nchains; i++) {
1927 			ipsec_ovhd = iptun_max_policy_overhead(
1928 			    ipr->ipr_hash[i].hash_head, ipsec_ovhd);
1929 		}
1930 		rw_exit(&iph->iph_lock);
1931 	}
1932 
1933 	return (ipsec_ovhd);
1934 }
1935 
1936 /*
1937  * Calculate and return the maximum possible upper MTU for the given tunnel.
1938  *
1939  * If new_pmtu is set then we also need to update the lower path MTU information
1940  * in the ip_xmit_attr_t. That is needed since we set IXAF_VERIFY_PMTU so that
1941  * we are notified by conn_ip_output() when the path MTU increases.
1942  */
1943 static uint32_t
1944 iptun_get_maxmtu(iptun_t *iptun, ip_xmit_attr_t *ixa, uint32_t new_pmtu)
1945 {
1946 	size_t		header_size, ipsec_overhead;
1947 	uint32_t	maxmtu, pmtu;
1948 
1949 	/*
1950 	 * Start with the path-MTU to the remote address, which is either
1951 	 * provided as the new_pmtu argument, or obtained using
1952 	 * iptun_get_dst_pmtu().
1953 	 */
1954 	if (new_pmtu != 0) {
1955 		if (iptun->iptun_flags & IPTUN_RADDR)
1956 			iptun->iptun_dpmtu = new_pmtu;
1957 		pmtu = new_pmtu;
1958 	} else if (iptun->iptun_flags & IPTUN_RADDR) {
1959 		if ((pmtu = iptun_get_dst_pmtu(iptun, ixa)) == 0) {
1960 			/*
1961 			 * We weren't able to obtain the path-MTU of the
1962 			 * destination.  Use the previous value.
1963 			 */
1964 			pmtu = iptun->iptun_dpmtu;
1965 		} else {
1966 			iptun->iptun_dpmtu = pmtu;
1967 		}
1968 	} else {
1969 		/*
1970 		 * We have no path-MTU information to go on, use the maximum
1971 		 * possible value.
1972 		 */
1973 		pmtu = iptun->iptun_typeinfo->iti_maxmtu;
1974 	}
1975 
1976 	/*
1977 	 * Now calculate tunneling overhead and subtract that from the
1978 	 * path-MTU information obtained above.
1979 	 */
1980 	if (iptun->iptun_header_size != 0) {
1981 		header_size = iptun->iptun_header_size;
1982 	} else {
1983 		switch (iptun->iptun_typeinfo->iti_ipvers) {
1984 		case IPV4_VERSION:
1985 			header_size = sizeof (ipha_t);
1986 			if (is_system_labeled())
1987 				header_size += IP_MAX_OPT_LENGTH;
1988 			break;
1989 		case IPV6_VERSION:
1990 			header_size = sizeof (iptun_ipv6hdrs_t);
1991 			break;
1992 		}
1993 	}
1994 
1995 	ipsec_overhead = iptun_get_ipsec_overhead(iptun);
1996 
1997 	maxmtu = pmtu - (header_size + ipsec_overhead);
1998 	return (max(maxmtu, iptun->iptun_typeinfo->iti_minmtu));
1999 }
2000 
2001 /*
2002  * Re-calculate the tunnel's MTU as seen from above and notify the MAC layer
2003  * of any change in MTU.  The new_pmtu argument is the new lower path MTU to
2004  * the tunnel destination to be used in the tunnel MTU calculation.  Passing
2005  * in 0 for new_pmtu causes the lower path MTU to be dynamically updated using
2006  * ip_get_pmtu().
2007  *
2008  * If the calculated tunnel MTU is different than its previous value, then we
2009  * notify the MAC layer above us of this change using mac_maxsdu_update().
2010  */
2011 static uint32_t
2012 iptun_update_mtu(iptun_t *iptun, ip_xmit_attr_t *ixa, uint32_t new_pmtu)
2013 {
2014 	uint32_t newmtu;
2015 
2016 	/* We always update the ixa since we might have set IXAF_VERIFY_PMTU */
2017 	iptun_update_dst_pmtu(iptun, ixa);
2018 
2019 	/*
2020 	 * We return the current MTU without updating it if it was pegged to a
2021 	 * static value using the MAC_PROP_MTU link property.
2022 	 */
2023 	if (iptun->iptun_flags & IPTUN_FIXED_MTU)
2024 		return (iptun->iptun_mtu);
2025 
2026 	/* If the MTU isn't fixed, then use the maximum possible value. */
2027 	newmtu = iptun_get_maxmtu(iptun, ixa, new_pmtu);
2028 	/*
2029 	 * We only dynamically adjust the tunnel MTU for tunnels with
2030 	 * destinations because dynamic MTU calculations are based on the
2031 	 * destination path-MTU.
2032 	 */
2033 	if ((iptun->iptun_flags & IPTUN_RADDR) && newmtu != iptun->iptun_mtu) {
2034 		iptun->iptun_mtu = newmtu;
2035 		if (iptun->iptun_flags & IPTUN_MAC_REGISTERED)
2036 			iptun_task_dispatch(iptun, IPTUN_TASK_MTU_UPDATE);
2037 	}
2038 
2039 	return (newmtu);
2040 }
2041 
2042 /*
2043  * Frees a packet or packet chain and bumps stat for each freed packet.
2044  */
2045 static void
2046 iptun_drop_pkt(mblk_t *mp, uint64_t *stat)
2047 {
2048 	mblk_t *pktmp;
2049 
2050 	for (pktmp = mp; pktmp != NULL; pktmp = mp) {
2051 		mp = mp->b_next;
2052 		pktmp->b_next = NULL;
2053 		if (stat != NULL)
2054 			atomic_inc_64(stat);
2055 		freemsg(pktmp);
2056 	}
2057 }
2058 
2059 /*
2060  * Allocate and return a new mblk to hold an IP and ICMP header, and chain the
2061  * original packet to its b_cont.  Returns NULL on failure.
2062  */
2063 static mblk_t *
2064 iptun_build_icmperr(size_t hdrs_size, mblk_t *orig_pkt)
2065 {
2066 	mblk_t *icmperr_mp;
2067 
2068 	if ((icmperr_mp = allocb(hdrs_size, BPRI_MED)) != NULL) {
2069 		icmperr_mp->b_wptr += hdrs_size;
2070 		/* tack on the offending packet */
2071 		icmperr_mp->b_cont = orig_pkt;
2072 	}
2073 	return (icmperr_mp);
2074 }
2075 
2076 /*
2077  * Transmit an ICMP error.  mp->b_rptr points at the packet to be included in
2078  * the ICMP error.
2079  */
2080 static void
2081 iptun_sendicmp_v4(iptun_t *iptun, icmph_t *icmp, ipha_t *orig_ipha, mblk_t *mp,
2082     ts_label_t *tsl)
2083 {
2084 	size_t	orig_pktsize, hdrs_size;
2085 	mblk_t	*icmperr_mp;
2086 	ipha_t	*new_ipha;
2087 	icmph_t	*new_icmp;
2088 	ip_xmit_attr_t	ixas;
2089 	conn_t	*connp = iptun->iptun_connp;
2090 
2091 	orig_pktsize = msgdsize(mp);
2092 	hdrs_size = sizeof (ipha_t) + sizeof (icmph_t);
2093 	if ((icmperr_mp = iptun_build_icmperr(hdrs_size, mp)) == NULL) {
2094 		iptun_drop_pkt(mp, &iptun->iptun_noxmtbuf);
2095 		return;
2096 	}
2097 
2098 	new_ipha = (ipha_t *)icmperr_mp->b_rptr;
2099 	new_icmp = (icmph_t *)(new_ipha + 1);
2100 
2101 	new_ipha->ipha_version_and_hdr_length = IP_SIMPLE_HDR_VERSION;
2102 	new_ipha->ipha_type_of_service = 0;
2103 	new_ipha->ipha_ident = 0;
2104 	new_ipha->ipha_fragment_offset_and_flags = 0;
2105 	new_ipha->ipha_ttl = orig_ipha->ipha_ttl;
2106 	new_ipha->ipha_protocol = IPPROTO_ICMP;
2107 	new_ipha->ipha_src = orig_ipha->ipha_dst;
2108 	new_ipha->ipha_dst = orig_ipha->ipha_src;
2109 	new_ipha->ipha_hdr_checksum = 0; /* will be computed by ip */
2110 	new_ipha->ipha_length = htons(hdrs_size + orig_pktsize);
2111 
2112 	*new_icmp = *icmp;
2113 	new_icmp->icmph_checksum = 0;
2114 	new_icmp->icmph_checksum = IP_CSUM(icmperr_mp, sizeof (ipha_t), 0);
2115 
2116 	bzero(&ixas, sizeof (ixas));
2117 	ixas.ixa_flags = IXAF_BASIC_SIMPLE_V4;
2118 	if (new_ipha->ipha_src == INADDR_ANY) {
2119 		ixas.ixa_flags &= ~IXAF_VERIFY_SOURCE;
2120 		ixas.ixa_flags |= IXAF_SET_SOURCE;
2121 	}
2122 
2123 	ixas.ixa_zoneid = IPCL_ZONEID(connp);
2124 	ixas.ixa_ipst = connp->conn_netstack->netstack_ip;
2125 	ixas.ixa_cred = connp->conn_cred;
2126 	ixas.ixa_cpid = NOPID;
2127 	if (is_system_labeled())
2128 		ixas.ixa_tsl = tsl;
2129 
2130 	ixas.ixa_ifindex = 0;
2131 	ixas.ixa_multicast_ttl = IP_DEFAULT_MULTICAST_TTL;
2132 
2133 	(void) ip_output_simple(icmperr_mp, &ixas);
2134 	ixa_cleanup(&ixas);
2135 }
2136 
2137 static void
2138 iptun_sendicmp_v6(iptun_t *iptun, icmp6_t *icmp6, ip6_t *orig_ip6h, mblk_t *mp,
2139     ts_label_t *tsl)
2140 {
2141 	size_t	orig_pktsize, hdrs_size;
2142 	mblk_t	*icmp6err_mp;
2143 	ip6_t	*new_ip6h;
2144 	icmp6_t	*new_icmp6;
2145 	ip_xmit_attr_t	ixas;
2146 	conn_t	*connp = iptun->iptun_connp;
2147 
2148 	orig_pktsize = msgdsize(mp);
2149 	hdrs_size = sizeof (ip6_t) + sizeof (icmp6_t);
2150 	if ((icmp6err_mp = iptun_build_icmperr(hdrs_size, mp)) == NULL) {
2151 		iptun_drop_pkt(mp, &iptun->iptun_noxmtbuf);
2152 		return;
2153 	}
2154 
2155 	new_ip6h = (ip6_t *)icmp6err_mp->b_rptr;
2156 	new_icmp6 = (icmp6_t *)(new_ip6h + 1);
2157 
2158 	new_ip6h->ip6_vcf = orig_ip6h->ip6_vcf;
2159 	new_ip6h->ip6_plen = htons(sizeof (icmp6_t) + orig_pktsize);
2160 	new_ip6h->ip6_hops = orig_ip6h->ip6_hops;
2161 	new_ip6h->ip6_nxt = IPPROTO_ICMPV6;
2162 	new_ip6h->ip6_src = orig_ip6h->ip6_dst;
2163 	new_ip6h->ip6_dst = orig_ip6h->ip6_src;
2164 
2165 	*new_icmp6 = *icmp6;
2166 	/* The checksum is calculated in ip_output_simple and friends. */
2167 	new_icmp6->icmp6_cksum = new_ip6h->ip6_plen;
2168 
2169 	bzero(&ixas, sizeof (ixas));
2170 	ixas.ixa_flags = IXAF_BASIC_SIMPLE_V6;
2171 	if (IN6_IS_ADDR_UNSPECIFIED(&new_ip6h->ip6_src)) {
2172 		ixas.ixa_flags &= ~IXAF_VERIFY_SOURCE;
2173 		ixas.ixa_flags |= IXAF_SET_SOURCE;
2174 	}
2175 
2176 	ixas.ixa_zoneid = IPCL_ZONEID(connp);
2177 	ixas.ixa_ipst = connp->conn_netstack->netstack_ip;
2178 	ixas.ixa_cred = connp->conn_cred;
2179 	ixas.ixa_cpid = NOPID;
2180 	if (is_system_labeled())
2181 		ixas.ixa_tsl = tsl;
2182 
2183 	ixas.ixa_ifindex = 0;
2184 	ixas.ixa_multicast_ttl = IP_DEFAULT_MULTICAST_TTL;
2185 
2186 	(void) ip_output_simple(icmp6err_mp, &ixas);
2187 	ixa_cleanup(&ixas);
2188 }
2189 
2190 static void
2191 iptun_icmp_error_v4(iptun_t *iptun, ipha_t *orig_ipha, mblk_t *mp,
2192     uint8_t type, uint8_t code, ts_label_t *tsl)
2193 {
2194 	icmph_t icmp;
2195 
2196 	bzero(&icmp, sizeof (icmp));
2197 	icmp.icmph_type = type;
2198 	icmp.icmph_code = code;
2199 
2200 	iptun_sendicmp_v4(iptun, &icmp, orig_ipha, mp, tsl);
2201 }
2202 
2203 static void
2204 iptun_icmp_fragneeded_v4(iptun_t *iptun, uint32_t newmtu, ipha_t *orig_ipha,
2205     mblk_t *mp, ts_label_t *tsl)
2206 {
2207 	icmph_t	icmp;
2208 
2209 	icmp.icmph_type = ICMP_DEST_UNREACHABLE;
2210 	icmp.icmph_code = ICMP_FRAGMENTATION_NEEDED;
2211 	icmp.icmph_du_zero = 0;
2212 	icmp.icmph_du_mtu = htons(newmtu);
2213 
2214 	iptun_sendicmp_v4(iptun, &icmp, orig_ipha, mp, tsl);
2215 }
2216 
2217 static void
2218 iptun_icmp_error_v6(iptun_t *iptun, ip6_t *orig_ip6h, mblk_t *mp,
2219     uint8_t type, uint8_t code, uint32_t offset, ts_label_t *tsl)
2220 {
2221 	icmp6_t icmp6;
2222 
2223 	bzero(&icmp6, sizeof (icmp6));
2224 	icmp6.icmp6_type = type;
2225 	icmp6.icmp6_code = code;
2226 	if (type == ICMP6_PARAM_PROB)
2227 		icmp6.icmp6_pptr = htonl(offset);
2228 
2229 	iptun_sendicmp_v6(iptun, &icmp6, orig_ip6h, mp, tsl);
2230 }
2231 
2232 static void
2233 iptun_icmp_toobig_v6(iptun_t *iptun, uint32_t newmtu, ip6_t *orig_ip6h,
2234     mblk_t *mp, ts_label_t *tsl)
2235 {
2236 	icmp6_t icmp6;
2237 
2238 	icmp6.icmp6_type = ICMP6_PACKET_TOO_BIG;
2239 	icmp6.icmp6_code = 0;
2240 	icmp6.icmp6_mtu = htonl(newmtu);
2241 
2242 	iptun_sendicmp_v6(iptun, &icmp6, orig_ip6h, mp, tsl);
2243 }
2244 
2245 /*
2246  * Determines if the packet pointed to by ipha or ip6h is an ICMP error.  The
2247  * mp argument is only used to do bounds checking.
2248  */
2249 static boolean_t
2250 is_icmp_error(mblk_t *mp, ipha_t *ipha, ip6_t *ip6h)
2251 {
2252 	uint16_t hlen;
2253 
2254 	if (ipha != NULL) {
2255 		icmph_t	*icmph;
2256 
2257 		ASSERT(ip6h == NULL);
2258 		if (ipha->ipha_protocol != IPPROTO_ICMP)
2259 			return (B_FALSE);
2260 
2261 		hlen = IPH_HDR_LENGTH(ipha);
2262 		icmph = (icmph_t *)((uint8_t *)ipha + hlen);
2263 		return (ICMP_IS_ERROR(icmph->icmph_type) ||
2264 		    icmph->icmph_type == ICMP_REDIRECT);
2265 	} else {
2266 		icmp6_t	*icmp6;
2267 		uint8_t	*nexthdrp;
2268 
2269 		ASSERT(ip6h != NULL);
2270 		if (!ip_hdr_length_nexthdr_v6(mp, ip6h, &hlen, &nexthdrp) ||
2271 		    *nexthdrp != IPPROTO_ICMPV6) {
2272 			return (B_FALSE);
2273 		}
2274 
2275 		icmp6 = (icmp6_t *)((uint8_t *)ip6h + hlen);
2276 		return (ICMP6_IS_ERROR(icmp6->icmp6_type) ||
2277 		    icmp6->icmp6_type == ND_REDIRECT);
2278 	}
2279 }
2280 
2281 /*
2282  * Find inner and outer IP headers from a tunneled packet as setup for calls
2283  * into ipsec_tun_{in,out}bound().
2284  * Note that we need to allow the outer header to be in a separate mblk from
2285  * the inner header.
2286  * If the caller knows the outer_hlen, the caller passes it in. Otherwise zero.
2287  */
2288 static size_t
2289 iptun_find_headers(mblk_t *mp, size_t outer_hlen, ipha_t **outer4,
2290     ipha_t **inner4, ip6_t **outer6, ip6_t **inner6)
2291 {
2292 	ipha_t	*ipha;
2293 	size_t	first_mblkl = MBLKL(mp);
2294 	mblk_t	*inner_mp;
2295 
2296 	/*
2297 	 * Don't bother handling packets that don't have a full IP header in
2298 	 * the fist mblk.  For the input path, the ip module ensures that this
2299 	 * won't happen, and on the output path, the IP tunneling MAC-type
2300 	 * plugins ensure that this also won't happen.
2301 	 */
2302 	if (first_mblkl < sizeof (ipha_t))
2303 		return (0);
2304 	ipha = (ipha_t *)(mp->b_rptr);
2305 	switch (IPH_HDR_VERSION(ipha)) {
2306 	case IPV4_VERSION:
2307 		*outer4 = ipha;
2308 		*outer6 = NULL;
2309 		if (outer_hlen == 0)
2310 			outer_hlen = IPH_HDR_LENGTH(ipha);
2311 		break;
2312 	case IPV6_VERSION:
2313 		*outer4 = NULL;
2314 		*outer6 = (ip6_t *)ipha;
2315 		if (outer_hlen == 0)
2316 			outer_hlen = ip_hdr_length_v6(mp, (ip6_t *)ipha);
2317 		break;
2318 	default:
2319 		return (0);
2320 	}
2321 
2322 	if (first_mblkl < outer_hlen ||
2323 	    (first_mblkl == outer_hlen && mp->b_cont == NULL))
2324 		return (0);
2325 
2326 	/*
2327 	 * We don't bother doing a pullup here since the outer header will
2328 	 * just get stripped off soon on input anyway.  We just want to ensure
2329 	 * that the inner* pointer points to a full header.
2330 	 */
2331 	if (first_mblkl == outer_hlen) {
2332 		inner_mp = mp->b_cont;
2333 		ipha = (ipha_t *)inner_mp->b_rptr;
2334 	} else {
2335 		inner_mp = mp;
2336 		ipha = (ipha_t *)(mp->b_rptr + outer_hlen);
2337 	}
2338 	switch (IPH_HDR_VERSION(ipha)) {
2339 	case IPV4_VERSION:
2340 		if (inner_mp->b_wptr - (uint8_t *)ipha < sizeof (ipha_t))
2341 			return (0);
2342 		*inner4 = ipha;
2343 		*inner6 = NULL;
2344 		break;
2345 	case IPV6_VERSION:
2346 		if (inner_mp->b_wptr - (uint8_t *)ipha < sizeof (ip6_t))
2347 			return (0);
2348 		*inner4 = NULL;
2349 		*inner6 = (ip6_t *)ipha;
2350 		break;
2351 	default:
2352 		return (0);
2353 	}
2354 
2355 	return (outer_hlen);
2356 }
2357 
2358 /*
2359  * Received ICMP error in response to an X over IPv4 packet that we
2360  * transmitted.
2361  *
2362  * NOTE: "outer" refers to what's inside the ICMP payload.  We will get one of
2363  * the following:
2364  *
2365  * [IPv4(0)][ICMPv4][IPv4(1)][IPv4(2)][ULP]
2366  *
2367  *	or
2368  *
2369  * [IPv4(0)][ICMPv4][IPv4(1)][IPv6][ULP]
2370  *
2371  * And "outer4" will get set to IPv4(1), and inner[46] will correspond to
2372  * whatever the very-inner packet is (IPv4(2) or IPv6).
2373  */
2374 static void
2375 iptun_input_icmp_v4(iptun_t *iptun, mblk_t *data_mp, icmph_t *icmph,
2376     ip_recv_attr_t *ira)
2377 {
2378 	uint8_t	*orig;
2379 	ipha_t	*outer4, *inner4;
2380 	ip6_t	*outer6, *inner6;
2381 	int	outer_hlen;
2382 	uint8_t	type, code;
2383 
2384 	ASSERT(data_mp->b_cont == NULL);
2385 	/*
2386 	 * Temporarily move b_rptr forward so that iptun_find_headers() can
2387 	 * find headers in the ICMP packet payload.
2388 	 */
2389 	orig = data_mp->b_rptr;
2390 	data_mp->b_rptr = (uint8_t *)(icmph + 1);
2391 	/*
2392 	 * The ip module ensures that ICMP errors contain at least the
2393 	 * original IP header (otherwise, the error would never have made it
2394 	 * here).
2395 	 */
2396 	ASSERT(MBLKL(data_mp) >= 0);
2397 	outer_hlen = iptun_find_headers(data_mp, 0, &outer4, &inner4, &outer6,
2398 	    &inner6);
2399 	ASSERT(outer6 == NULL);
2400 	data_mp->b_rptr = orig;
2401 	if (outer_hlen == 0) {
2402 		iptun_drop_pkt(data_mp, &iptun->iptun_ierrors);
2403 		return;
2404 	}
2405 
2406 	/* Only ICMP errors due to tunneled packets should reach here. */
2407 	ASSERT(outer4->ipha_protocol == IPPROTO_ENCAP ||
2408 	    outer4->ipha_protocol == IPPROTO_IPV6);
2409 
2410 	data_mp = ipsec_tun_inbound(ira, data_mp, iptun->iptun_itp,
2411 	    inner4, inner6, outer4, outer6, -outer_hlen, iptun->iptun_ns);
2412 	if (data_mp == NULL) {
2413 		/* Callee did all of the freeing. */
2414 		atomic_inc_64(&iptun->iptun_ierrors);
2415 		return;
2416 	}
2417 	/* We should never see reassembled fragment here. */
2418 	ASSERT(data_mp->b_next == NULL);
2419 
2420 	data_mp->b_rptr = (uint8_t *)outer4 + outer_hlen;
2421 
2422 	/*
2423 	 * If the original packet being transmitted was itself an ICMP error,
2424 	 * then drop this packet.  We don't want to generate an ICMP error in
2425 	 * response to an ICMP error.
2426 	 */
2427 	if (is_icmp_error(data_mp, inner4, inner6)) {
2428 		iptun_drop_pkt(data_mp, &iptun->iptun_norcvbuf);
2429 		return;
2430 	}
2431 
2432 	switch (icmph->icmph_type) {
2433 	case ICMP_DEST_UNREACHABLE:
2434 		type = (inner4 != NULL ? icmph->icmph_type : ICMP6_DST_UNREACH);
2435 		switch (icmph->icmph_code) {
2436 		case ICMP_FRAGMENTATION_NEEDED: {
2437 			uint32_t newmtu;
2438 
2439 			/*
2440 			 * We reconcile this with the fact that the tunnel may
2441 			 * also have IPsec policy by letting iptun_update_mtu
2442 			 * take care of it.
2443 			 */
2444 			newmtu = iptun_update_mtu(iptun, NULL,
2445 			    ntohs(icmph->icmph_du_mtu));
2446 
2447 			if (inner4 != NULL) {
2448 				iptun_icmp_fragneeded_v4(iptun, newmtu, inner4,
2449 				    data_mp, ira->ira_tsl);
2450 			} else {
2451 				iptun_icmp_toobig_v6(iptun, newmtu, inner6,
2452 				    data_mp, ira->ira_tsl);
2453 			}
2454 			return;
2455 		}
2456 		case ICMP_DEST_NET_UNREACH_ADMIN:
2457 		case ICMP_DEST_HOST_UNREACH_ADMIN:
2458 			code = (inner4 != NULL ? ICMP_DEST_NET_UNREACH_ADMIN :
2459 			    ICMP6_DST_UNREACH_ADMIN);
2460 			break;
2461 		default:
2462 			code = (inner4 != NULL ? ICMP_HOST_UNREACHABLE :
2463 			    ICMP6_DST_UNREACH_ADDR);
2464 			break;
2465 		}
2466 		break;
2467 	case ICMP_TIME_EXCEEDED:
2468 		if (inner6 != NULL) {
2469 			type = ICMP6_TIME_EXCEEDED;
2470 			code = 0;
2471 		} /* else we're already set. */
2472 		break;
2473 	case ICMP_PARAM_PROBLEM:
2474 		/*
2475 		 * This is a problem with the outer header we transmitted.
2476 		 * Treat this as an output error.
2477 		 */
2478 		iptun_drop_pkt(data_mp, &iptun->iptun_oerrors);
2479 		return;
2480 	default:
2481 		iptun_drop_pkt(data_mp, &iptun->iptun_norcvbuf);
2482 		return;
2483 	}
2484 
2485 	if (inner4 != NULL) {
2486 		iptun_icmp_error_v4(iptun, inner4, data_mp, type, code,
2487 		    ira->ira_tsl);
2488 	} else {
2489 		iptun_icmp_error_v6(iptun, inner6, data_mp, type, code, 0,
2490 		    ira->ira_tsl);
2491 	}
2492 }
2493 
2494 /*
2495  * Return B_TRUE if the IPv6 packet pointed to by ip6h contains a Tunnel
2496  * Encapsulation Limit destination option.  If there is one, set encaplim_ptr
2497  * to point to the option value.
2498  */
2499 static boolean_t
2500 iptun_find_encaplimit(mblk_t *mp, ip6_t *ip6h, uint8_t **encaplim_ptr)
2501 {
2502 	ip_pkt_t	pkt;
2503 	uint8_t		*endptr;
2504 	ip6_dest_t	*destp;
2505 	struct ip6_opt	*optp;
2506 
2507 	pkt.ipp_fields = 0; /* must be initialized */
2508 	(void) ip_find_hdr_v6(mp, ip6h, B_FALSE, &pkt, NULL);
2509 	if ((pkt.ipp_fields & IPPF_DSTOPTS) != 0) {
2510 		destp = pkt.ipp_dstopts;
2511 	} else if ((pkt.ipp_fields & IPPF_RTHDRDSTOPTS) != 0) {
2512 		destp = pkt.ipp_rthdrdstopts;
2513 	} else {
2514 		return (B_FALSE);
2515 	}
2516 
2517 	endptr = (uint8_t *)destp + 8 * (destp->ip6d_len + 1);
2518 	optp = (struct ip6_opt *)(destp + 1);
2519 	while (endptr - (uint8_t *)optp > sizeof (*optp)) {
2520 		if (optp->ip6o_type == IP6OPT_TUNNEL_LIMIT) {
2521 			if ((uint8_t *)(optp + 1) >= endptr)
2522 				return (B_FALSE);
2523 			*encaplim_ptr = (uint8_t *)&optp[1];
2524 			return (B_TRUE);
2525 		}
2526 		optp = (struct ip6_opt *)((uint8_t *)optp + optp->ip6o_len + 2);
2527 	}
2528 	return (B_FALSE);
2529 }
2530 
2531 /*
2532  * Received ICMPv6 error in response to an X over IPv6 packet that we
2533  * transmitted.
2534  *
2535  * NOTE: "outer" refers to what's inside the ICMP payload.  We will get one of
2536  * the following:
2537  *
2538  * [IPv6(0)][ICMPv6][IPv6(1)][IPv4][ULP]
2539  *
2540  *	or
2541  *
2542  * [IPv6(0)][ICMPv6][IPv6(1)][IPv6(2)][ULP]
2543  *
2544  * And "outer6" will get set to IPv6(1), and inner[46] will correspond to
2545  * whatever the very-inner packet is (IPv4 or IPv6(2)).
2546  */
2547 static void
2548 iptun_input_icmp_v6(iptun_t *iptun, mblk_t *data_mp, icmp6_t *icmp6h,
2549     ip_recv_attr_t *ira)
2550 {
2551 	uint8_t	*orig;
2552 	ipha_t	*outer4, *inner4;
2553 	ip6_t	*outer6, *inner6;
2554 	int	outer_hlen;
2555 	uint8_t	type, code;
2556 
2557 	ASSERT(data_mp->b_cont == NULL);
2558 
2559 	/*
2560 	 * Temporarily move b_rptr forward so that iptun_find_headers() can
2561 	 * find IP headers in the ICMP packet payload.
2562 	 */
2563 	orig = data_mp->b_rptr;
2564 	data_mp->b_rptr = (uint8_t *)(icmp6h + 1);
2565 	/*
2566 	 * The ip module ensures that ICMP errors contain at least the
2567 	 * original IP header (otherwise, the error would never have made it
2568 	 * here).
2569 	 */
2570 	ASSERT(MBLKL(data_mp) >= 0);
2571 	outer_hlen = iptun_find_headers(data_mp, 0, &outer4, &inner4, &outer6,
2572 	    &inner6);
2573 	ASSERT(outer4 == NULL);
2574 	data_mp->b_rptr = orig;	/* Restore r_ptr */
2575 	if (outer_hlen == 0) {
2576 		iptun_drop_pkt(data_mp, &iptun->iptun_ierrors);
2577 		return;
2578 	}
2579 
2580 	data_mp = ipsec_tun_inbound(ira, data_mp, iptun->iptun_itp,
2581 	    inner4, inner6, outer4, outer6, -outer_hlen, iptun->iptun_ns);
2582 	if (data_mp == NULL) {
2583 		/* Callee did all of the freeing. */
2584 		atomic_inc_64(&iptun->iptun_ierrors);
2585 		return;
2586 	}
2587 	/* We should never see reassembled fragment here. */
2588 	ASSERT(data_mp->b_next == NULL);
2589 
2590 	data_mp->b_rptr = (uint8_t *)outer6 + outer_hlen;
2591 
2592 	/*
2593 	 * If the original packet being transmitted was itself an ICMP error,
2594 	 * then drop this packet.  We don't want to generate an ICMP error in
2595 	 * response to an ICMP error.
2596 	 */
2597 	if (is_icmp_error(data_mp, inner4, inner6)) {
2598 		iptun_drop_pkt(data_mp, &iptun->iptun_norcvbuf);
2599 		return;
2600 	}
2601 
2602 	switch (icmp6h->icmp6_type) {
2603 	case ICMP6_PARAM_PROB: {
2604 		uint8_t *encaplim_ptr;
2605 
2606 		/*
2607 		 * If the ICMPv6 error points to a valid Tunnel Encapsulation
2608 		 * Limit option and the limit value is 0, then fall through
2609 		 * and send a host unreachable message.  Otherwise, treat the
2610 		 * error as an output error, as there must have been a problem
2611 		 * with a packet we sent.
2612 		 */
2613 		if (!iptun_find_encaplimit(data_mp, outer6, &encaplim_ptr) ||
2614 		    (icmp6h->icmp6_pptr !=
2615 		    ((ptrdiff_t)encaplim_ptr - (ptrdiff_t)outer6)) ||
2616 		    *encaplim_ptr != 0) {
2617 			iptun_drop_pkt(data_mp, &iptun->iptun_oerrors);
2618 			return;
2619 		}
2620 		/* FALLTHRU */
2621 	}
2622 	case ICMP6_TIME_EXCEEDED:
2623 	case ICMP6_DST_UNREACH:
2624 		type = (inner4 != NULL ? ICMP_DEST_UNREACHABLE :
2625 		    ICMP6_DST_UNREACH);
2626 		code = (inner4 != NULL ? ICMP_HOST_UNREACHABLE :
2627 		    ICMP6_DST_UNREACH_ADDR);
2628 		break;
2629 	case ICMP6_PACKET_TOO_BIG: {
2630 		uint32_t newmtu;
2631 
2632 		/*
2633 		 * We reconcile this with the fact that the tunnel may also
2634 		 * have IPsec policy by letting iptun_update_mtu take care of
2635 		 * it.
2636 		 */
2637 		newmtu = iptun_update_mtu(iptun, NULL,
2638 		    ntohl(icmp6h->icmp6_mtu));
2639 
2640 		if (inner4 != NULL) {
2641 			iptun_icmp_fragneeded_v4(iptun, newmtu, inner4,
2642 			    data_mp, ira->ira_tsl);
2643 		} else {
2644 			iptun_icmp_toobig_v6(iptun, newmtu, inner6, data_mp,
2645 			    ira->ira_tsl);
2646 		}
2647 		return;
2648 	}
2649 	default:
2650 		iptun_drop_pkt(data_mp, &iptun->iptun_norcvbuf);
2651 		return;
2652 	}
2653 
2654 	if (inner4 != NULL) {
2655 		iptun_icmp_error_v4(iptun, inner4, data_mp, type, code,
2656 		    ira->ira_tsl);
2657 	} else {
2658 		iptun_icmp_error_v6(iptun, inner6, data_mp, type, code, 0,
2659 		    ira->ira_tsl);
2660 	}
2661 }
2662 
2663 /*
2664  * Called as conn_recvicmp from IP for ICMP errors.
2665  */
2666 /* ARGSUSED2 */
2667 static void
2668 iptun_input_icmp(void *arg, mblk_t *mp, void *arg2, ip_recv_attr_t *ira)
2669 {
2670 	conn_t		*connp = arg;
2671 	iptun_t		*iptun = connp->conn_iptun;
2672 	mblk_t		*tmpmp;
2673 	size_t		hlen;
2674 
2675 	ASSERT(IPCL_IS_IPTUN(connp));
2676 
2677 	if (mp->b_cont != NULL) {
2678 		/*
2679 		 * Since ICMP error processing necessitates access to bits
2680 		 * that are within the ICMP error payload (the original packet
2681 		 * that caused the error), pull everything up into a single
2682 		 * block for convenience.
2683 		 */
2684 		if ((tmpmp = msgpullup(mp, -1)) == NULL) {
2685 			iptun_drop_pkt(mp, &iptun->iptun_norcvbuf);
2686 			return;
2687 		}
2688 		freemsg(mp);
2689 		mp = tmpmp;
2690 	}
2691 
2692 	hlen = ira->ira_ip_hdr_length;
2693 	switch (iptun->iptun_typeinfo->iti_ipvers) {
2694 	case IPV4_VERSION:
2695 		/*
2696 		 * The outer IP header coming up from IP is always ipha_t
2697 		 * alligned (otherwise, we would have crashed in ip).
2698 		 */
2699 		iptun_input_icmp_v4(iptun, mp, (icmph_t *)(mp->b_rptr + hlen),
2700 		    ira);
2701 		break;
2702 	case IPV6_VERSION:
2703 		iptun_input_icmp_v6(iptun, mp, (icmp6_t *)(mp->b_rptr + hlen),
2704 		    ira);
2705 		break;
2706 	}
2707 }
2708 
2709 static boolean_t
2710 iptun_in_6to4_ok(iptun_t *iptun, ipha_t *outer4, ip6_t *inner6)
2711 {
2712 	ipaddr_t v4addr;
2713 
2714 	/*
2715 	 * It's possible that someone sent us an IPv4-in-IPv4 packet with the
2716 	 * IPv4 address of a 6to4 tunnel as the destination.
2717 	 */
2718 	if (inner6 == NULL)
2719 		return (B_FALSE);
2720 
2721 	/*
2722 	 * Make sure that the IPv6 destination is within the site that this
2723 	 * 6to4 tunnel is routing for.  We don't want people bouncing random
2724 	 * tunneled IPv6 packets through this 6to4 router.
2725 	 */
2726 	IN6_6TO4_TO_V4ADDR(&inner6->ip6_dst, (struct in_addr *)&v4addr);
2727 	if (outer4->ipha_dst != v4addr)
2728 		return (B_FALSE);
2729 
2730 	if (IN6_IS_ADDR_6TO4(&inner6->ip6_src)) {
2731 		/*
2732 		 * Section 9 of RFC 3056 (security considerations) suggests
2733 		 * that when a packet is from a 6to4 site (i.e., it's not a
2734 		 * global address being forwarded froma relay router), make
2735 		 * sure that the packet was tunneled by that site's 6to4
2736 		 * router.
2737 		 */
2738 		IN6_6TO4_TO_V4ADDR(&inner6->ip6_src, (struct in_addr *)&v4addr);
2739 		if (outer4->ipha_src != v4addr)
2740 			return (B_FALSE);
2741 	} else {
2742 		/*
2743 		 * Only accept packets from a relay router if we've configured
2744 		 * outbound relay router functionality.
2745 		 */
2746 		if (iptun->iptun_iptuns->iptuns_relay_rtr_addr == INADDR_ANY)
2747 			return (B_FALSE);
2748 	}
2749 
2750 	return (B_TRUE);
2751 }
2752 
2753 /*
2754  * Input function for everything that comes up from the ip module below us.
2755  * This is called directly from the ip module via connp->conn_recv().
2756  *
2757  * We receive M_DATA messages with IP-in-IP tunneled packets.
2758  */
2759 /* ARGSUSED2 */
2760 static void
2761 iptun_input(void *arg, mblk_t *data_mp, void *arg2, ip_recv_attr_t *ira)
2762 {
2763 	conn_t	*connp = arg;
2764 	iptun_t	*iptun = connp->conn_iptun;
2765 	int	outer_hlen;
2766 	ipha_t	*outer4, *inner4;
2767 	ip6_t	*outer6, *inner6;
2768 
2769 	ASSERT(IPCL_IS_IPTUN(connp));
2770 	ASSERT(DB_TYPE(data_mp) == M_DATA);
2771 
2772 	outer_hlen = iptun_find_headers(data_mp, ira->ira_ip_hdr_length,
2773 	    &outer4, &inner4, &outer6, &inner6);
2774 	if (outer_hlen == 0)
2775 		goto drop;
2776 
2777 	/*
2778 	 * If the system is labeled, we call tsol_check_dest() on the packet
2779 	 * destination (our local tunnel address) to ensure that the packet as
2780 	 * labeled should be allowed to be sent to us.  We don't need to call
2781 	 * the more involved tsol_receive_local() since the tunnel link itself
2782 	 * cannot be assigned to shared-stack non-global zones.
2783 	 */
2784 	if (ira->ira_flags & IRAF_SYSTEM_LABELED) {
2785 		if (ira->ira_tsl == NULL)
2786 			goto drop;
2787 		if (tsol_check_dest(ira->ira_tsl, (outer4 != NULL ?
2788 		    (void *)&outer4->ipha_dst : (void *)&outer6->ip6_dst),
2789 		    (outer4 != NULL ? IPV4_VERSION : IPV6_VERSION),
2790 		    CONN_MAC_DEFAULT, B_FALSE, NULL) != 0)
2791 			goto drop;
2792 	}
2793 
2794 	data_mp = ipsec_tun_inbound(ira, data_mp, iptun->iptun_itp,
2795 	    inner4, inner6, outer4, outer6, outer_hlen, iptun->iptun_ns);
2796 	if (data_mp == NULL) {
2797 		/* Callee did all of the freeing. */
2798 		return;
2799 	}
2800 
2801 	if (iptun->iptun_typeinfo->iti_type == IPTUN_TYPE_6TO4 &&
2802 	    !iptun_in_6to4_ok(iptun, outer4, inner6))
2803 		goto drop;
2804 
2805 	/*
2806 	 * We need to statistically account for each packet individually, so
2807 	 * we might as well split up any b_next chains here.
2808 	 */
2809 	do {
2810 		mblk_t	*mp;
2811 
2812 		mp = data_mp->b_next;
2813 		data_mp->b_next = NULL;
2814 
2815 		atomic_inc_64(&iptun->iptun_ipackets);
2816 		atomic_add_64(&iptun->iptun_rbytes, msgdsize(data_mp));
2817 		mac_rx(iptun->iptun_mh, NULL, data_mp);
2818 
2819 		data_mp = mp;
2820 	} while (data_mp != NULL);
2821 	return;
2822 drop:
2823 	iptun_drop_pkt(data_mp, &iptun->iptun_ierrors);
2824 }
2825 
2826 /*
2827  * Do 6to4-specific header-processing on output.  Return B_TRUE if the packet
2828  * was processed without issue, or B_FALSE if the packet had issues and should
2829  * be dropped.
2830  */
2831 static boolean_t
2832 iptun_out_process_6to4(iptun_t *iptun, ipha_t *outer4, ip6_t *inner6)
2833 {
2834 	ipaddr_t v4addr;
2835 
2836 	/*
2837 	 * IPv6 source must be a 6to4 address.  This is because a conscious
2838 	 * decision was made to not allow a Solaris system to be used as a
2839 	 * relay router (for security reasons) when 6to4 was initially
2840 	 * integrated.  If this decision is ever reversed, the following check
2841 	 * can be removed.
2842 	 */
2843 	if (!IN6_IS_ADDR_6TO4(&inner6->ip6_src))
2844 		return (B_FALSE);
2845 
2846 	/*
2847 	 * RFC3056 mandates that the IPv4 source MUST be set to the IPv4
2848 	 * portion of the 6to4 IPv6 source address.  In other words, make sure
2849 	 * that we're tunneling packets from our own 6to4 site.
2850 	 */
2851 	IN6_6TO4_TO_V4ADDR(&inner6->ip6_src, (struct in_addr *)&v4addr);
2852 	if (outer4->ipha_src != v4addr)
2853 		return (B_FALSE);
2854 
2855 	/*
2856 	 * Automatically set the destination of the outer IPv4 header as
2857 	 * described in RFC3056.  There are two possibilities:
2858 	 *
2859 	 * a. If the IPv6 destination is a 6to4 address, set the IPv4 address
2860 	 *    to the IPv4 portion of the 6to4 address.
2861 	 * b. If the IPv6 destination is a native IPv6 address, set the IPv4
2862 	 *    destination to the address of a relay router.
2863 	 *
2864 	 * Design Note: b shouldn't be necessary here, and this is a flaw in
2865 	 * the design of the 6to4relay command.  Instead of setting a 6to4
2866 	 * relay address in this module via an ioctl, the 6to4relay command
2867 	 * could simply add a IPv6 route for native IPv6 addresses (such as a
2868 	 * default route) in the forwarding table that uses a 6to4 destination
2869 	 * as its next hop, and the IPv4 portion of that address could be a
2870 	 * 6to4 relay address.  In order for this to work, IP would have to
2871 	 * resolve the next hop address, which would necessitate a link-layer
2872 	 * address resolver for 6to4 links, which doesn't exist today.
2873 	 *
2874 	 * In fact, if a resolver existed for 6to4 links, then setting the
2875 	 * IPv4 destination in the outer header could be done as part of
2876 	 * link-layer address resolution and fast-path header generation, and
2877 	 * not here.
2878 	 */
2879 	if (IN6_IS_ADDR_6TO4(&inner6->ip6_dst)) {
2880 		/* destination is a 6to4 router */
2881 		IN6_6TO4_TO_V4ADDR(&inner6->ip6_dst,
2882 		    (struct in_addr *)&outer4->ipha_dst);
2883 
2884 		/* Reject attempts to send to INADDR_ANY */
2885 		if (outer4->ipha_dst == INADDR_ANY)
2886 			return (B_FALSE);
2887 	} else {
2888 		/*
2889 		 * The destination is a native IPv6 address.  If output to a
2890 		 * relay-router is enabled, use the relay-router's IPv4
2891 		 * address as the destination.
2892 		 */
2893 		if (iptun->iptun_iptuns->iptuns_relay_rtr_addr == INADDR_ANY)
2894 			return (B_FALSE);
2895 		outer4->ipha_dst = iptun->iptun_iptuns->iptuns_relay_rtr_addr;
2896 	}
2897 
2898 	/*
2899 	 * If the outer source and destination are equal, this means that the
2900 	 * 6to4 router somehow forwarded an IPv6 packet destined for its own
2901 	 * 6to4 site to its 6to4 tunnel interface, which will result in this
2902 	 * packet infinitely bouncing between ip and iptun.
2903 	 */
2904 	return (outer4->ipha_src != outer4->ipha_dst);
2905 }
2906 
2907 /*
2908  * Process output packets with outer IPv4 headers.  Frees mp and bumps stat on
2909  * error.
2910  */
2911 static mblk_t *
2912 iptun_out_process_ipv4(iptun_t *iptun, mblk_t *mp, ipha_t *outer4,
2913     ipha_t *inner4, ip6_t *inner6, ip_xmit_attr_t *ixa)
2914 {
2915 	uint8_t	*innerptr = (inner4 != NULL ?
2916 	    (uint8_t *)inner4 : (uint8_t *)inner6);
2917 	size_t	minmtu = iptun->iptun_typeinfo->iti_minmtu;
2918 
2919 	if (inner4 != NULL) {
2920 		ASSERT(outer4->ipha_protocol == IPPROTO_ENCAP);
2921 		/*
2922 		 * Copy the tos from the inner IPv4 header. We mask off ECN
2923 		 * bits (bits 6 and 7) because there is currently no
2924 		 * tunnel-tunnel communication to determine if both sides
2925 		 * support ECN.  We opt for the safe choice: don't copy the
2926 		 * ECN bits when doing encapsulation.
2927 		 */
2928 		outer4->ipha_type_of_service =
2929 		    inner4->ipha_type_of_service & ~0x03;
2930 	} else {
2931 		ASSERT(outer4->ipha_protocol == IPPROTO_IPV6 &&
2932 		    inner6 != NULL);
2933 	}
2934 	if (ixa->ixa_flags & IXAF_PMTU_IPV4_DF)
2935 		outer4->ipha_fragment_offset_and_flags |= IPH_DF_HTONS;
2936 	else
2937 		outer4->ipha_fragment_offset_and_flags &= ~IPH_DF_HTONS;
2938 
2939 	/*
2940 	 * As described in section 3.2.2 of RFC4213, if the packet payload is
2941 	 * less than or equal to the minimum MTU size, then we need to allow
2942 	 * IPv4 to fragment the packet.  The reason is that even if we end up
2943 	 * receiving an ICMP frag-needed, the interface above this tunnel
2944 	 * won't be allowed to drop its MTU as a result, since the packet was
2945 	 * already smaller than the smallest allowable MTU for that interface.
2946 	 */
2947 	if (mp->b_wptr - innerptr <= minmtu) {
2948 		outer4->ipha_fragment_offset_and_flags = 0;
2949 		ixa->ixa_flags &= ~IXAF_DONTFRAG;
2950 	} else if (!(ixa->ixa_flags & IXAF_PMTU_TOO_SMALL) &&
2951 	    (iptun->iptun_typeinfo->iti_type != IPTUN_TYPE_6TO4)) {
2952 		ixa->ixa_flags |= IXAF_DONTFRAG;
2953 	}
2954 
2955 	ixa->ixa_ip_hdr_length = IPH_HDR_LENGTH(outer4);
2956 	ixa->ixa_pktlen = msgdsize(mp);
2957 	ixa->ixa_protocol = outer4->ipha_protocol;
2958 
2959 	outer4->ipha_length = htons(ixa->ixa_pktlen);
2960 	return (mp);
2961 }
2962 
2963 /*
2964  * Insert an encapsulation limit destination option in the packet provided.
2965  * Always consumes the mp argument and returns a new mblk pointer.
2966  */
2967 static mblk_t *
2968 iptun_insert_encaplimit(iptun_t *iptun, mblk_t *mp, ip6_t *outer6,
2969     uint8_t limit)
2970 {
2971 	mblk_t			*newmp;
2972 	iptun_ipv6hdrs_t	*newouter6;
2973 
2974 	ASSERT(outer6->ip6_nxt == IPPROTO_IPV6);
2975 	ASSERT(mp->b_cont == NULL);
2976 
2977 	mp->b_rptr += sizeof (ip6_t);
2978 	newmp = allocb(sizeof (iptun_ipv6hdrs_t) + MBLKL(mp), BPRI_MED);
2979 	if (newmp == NULL) {
2980 		iptun_drop_pkt(mp, &iptun->iptun_noxmtbuf);
2981 		return (NULL);
2982 	}
2983 	newmp->b_wptr += sizeof (iptun_ipv6hdrs_t);
2984 	/* Copy the payload (Starting with the inner IPv6 header). */
2985 	bcopy(mp->b_rptr, newmp->b_wptr, MBLKL(mp));
2986 	newmp->b_wptr += MBLKL(mp);
2987 	newouter6 = (iptun_ipv6hdrs_t *)newmp->b_rptr;
2988 	/* Now copy the outer IPv6 header. */
2989 	bcopy(outer6, &newouter6->it6h_ip6h, sizeof (ip6_t));
2990 	newouter6->it6h_ip6h.ip6_nxt = IPPROTO_DSTOPTS;
2991 	newouter6->it6h_encaplim = iptun_encaplim_init;
2992 	newouter6->it6h_encaplim.iel_destopt.ip6d_nxt = outer6->ip6_nxt;
2993 	newouter6->it6h_encaplim.iel_telopt.ip6ot_encap_limit = limit;
2994 
2995 	/*
2996 	 * The payload length will be set at the end of
2997 	 * iptun_out_process_ipv6().
2998 	 */
2999 
3000 	freemsg(mp);
3001 	return (newmp);
3002 }
3003 
3004 /*
3005  * Process output packets with outer IPv6 headers.  Frees mp and bumps stats
3006  * on error.
3007  */
3008 static mblk_t *
3009 iptun_out_process_ipv6(iptun_t *iptun, mblk_t *mp, ip6_t *outer6,
3010     ipha_t *inner4, ip6_t *inner6, ip_xmit_attr_t *ixa)
3011 {
3012 	uint8_t		*innerptr = (inner4 != NULL ?
3013 	    (uint8_t *)inner4 : (uint8_t *)inner6);
3014 	size_t		minmtu = iptun->iptun_typeinfo->iti_minmtu;
3015 	uint8_t		*limit, *configlimit;
3016 	uint32_t	offset;
3017 	iptun_ipv6hdrs_t *v6hdrs;
3018 
3019 	if (inner6 != NULL && iptun_find_encaplimit(mp, inner6, &limit)) {
3020 		/*
3021 		 * The inner packet is an IPv6 packet which itself contains an
3022 		 * encapsulation limit option.  The limit variable points to
3023 		 * the value in the embedded option.  Process the
3024 		 * encapsulation limit option as specified in RFC 2473.
3025 		 *
3026 		 * If limit is 0, then we've exceeded the limit and we need to
3027 		 * send back an ICMPv6 parameter problem message.
3028 		 *
3029 		 * If limit is > 0, then we decrement it by 1 and make sure
3030 		 * that the encapsulation limit option in the outer header
3031 		 * reflects that (adding an option if one isn't already
3032 		 * there).
3033 		 */
3034 		ASSERT(limit > mp->b_rptr && limit < mp->b_wptr);
3035 		if (*limit == 0) {
3036 			mp->b_rptr = (uint8_t *)inner6;
3037 			offset = limit - mp->b_rptr;
3038 			iptun_icmp_error_v6(iptun, inner6, mp, ICMP6_PARAM_PROB,
3039 			    0, offset, ixa->ixa_tsl);
3040 			atomic_inc_64(&iptun->iptun_noxmtbuf);
3041 			return (NULL);
3042 		}
3043 
3044 		/*
3045 		 * The outer header requires an encapsulation limit option.
3046 		 * If there isn't one already, add one.
3047 		 */
3048 		if (iptun->iptun_encaplimit == 0) {
3049 			if ((mp = iptun_insert_encaplimit(iptun, mp, outer6,
3050 			    (*limit - 1))) == NULL)
3051 				return (NULL);
3052 			v6hdrs = (iptun_ipv6hdrs_t *)mp->b_rptr;
3053 		} else {
3054 			/*
3055 			 * There is an existing encapsulation limit option in
3056 			 * the outer header.  If the inner encapsulation limit
3057 			 * is less than the configured encapsulation limit,
3058 			 * update the outer encapsulation limit to reflect
3059 			 * this lesser value.
3060 			 */
3061 			v6hdrs = (iptun_ipv6hdrs_t *)mp->b_rptr;
3062 			configlimit =
3063 			    &v6hdrs->it6h_encaplim.iel_telopt.ip6ot_encap_limit;
3064 			if ((*limit - 1) < *configlimit)
3065 				*configlimit = (*limit - 1);
3066 		}
3067 		ixa->ixa_ip_hdr_length = sizeof (iptun_ipv6hdrs_t);
3068 		ixa->ixa_protocol = v6hdrs->it6h_encaplim.iel_destopt.ip6d_nxt;
3069 	} else {
3070 		ixa->ixa_ip_hdr_length = sizeof (ip6_t);
3071 		ixa->ixa_protocol = outer6->ip6_nxt;
3072 	}
3073 	/*
3074 	 * See iptun_output_process_ipv4() why we allow fragmentation for
3075 	 * small packets
3076 	 */
3077 	if (mp->b_wptr - innerptr <= minmtu)
3078 		ixa->ixa_flags &= ~IXAF_DONTFRAG;
3079 	else if (!(ixa->ixa_flags & IXAF_PMTU_TOO_SMALL))
3080 		ixa->ixa_flags |= IXAF_DONTFRAG;
3081 
3082 	ixa->ixa_pktlen = msgdsize(mp);
3083 	outer6->ip6_plen = htons(ixa->ixa_pktlen - sizeof (ip6_t));
3084 	return (mp);
3085 }
3086 
3087 /*
3088  * The IP tunneling MAC-type plugins have already done most of the header
3089  * processing and validity checks.  We are simply responsible for multiplexing
3090  * down to the ip module below us.
3091  */
3092 static void
3093 iptun_output(iptun_t *iptun, mblk_t *mp)
3094 {
3095 	conn_t	*connp = iptun->iptun_connp;
3096 	mblk_t	*newmp;
3097 	int	error;
3098 	ip_xmit_attr_t	*ixa;
3099 
3100 	ASSERT(mp->b_datap->db_type == M_DATA);
3101 
3102 	if (mp->b_cont != NULL) {
3103 		if ((newmp = msgpullup(mp, -1)) == NULL) {
3104 			iptun_drop_pkt(mp, &iptun->iptun_noxmtbuf);
3105 			return;
3106 		}
3107 		freemsg(mp);
3108 		mp = newmp;
3109 	}
3110 
3111 	if (iptun->iptun_typeinfo->iti_type == IPTUN_TYPE_6TO4) {
3112 		iptun_output_6to4(iptun, mp);
3113 		return;
3114 	}
3115 
3116 	if (is_system_labeled()) {
3117 		/*
3118 		 * Since the label can be different meaning a potentially
3119 		 * different IRE,we always use a unique ip_xmit_attr_t.
3120 		 */
3121 		ixa = conn_get_ixa_exclusive(connp);
3122 	} else {
3123 		/*
3124 		 * If no other thread is using conn_ixa this just gets a
3125 		 * reference to conn_ixa. Otherwise we get a safe copy of
3126 		 * conn_ixa.
3127 		 */
3128 		ixa = conn_get_ixa(connp, B_FALSE);
3129 	}
3130 	if (ixa == NULL) {
3131 		iptun_drop_pkt(mp, &iptun->iptun_oerrors);
3132 		return;
3133 	}
3134 
3135 	/*
3136 	 * In case we got a safe copy of conn_ixa, then we need
3137 	 * to fill in any pointers in it.
3138 	 */
3139 	if (ixa->ixa_ire == NULL) {
3140 		error = ip_attr_connect(connp, ixa, &connp->conn_saddr_v6,
3141 		    &connp->conn_faddr_v6, &connp->conn_faddr_v6, 0,
3142 		    NULL, NULL, 0);
3143 		if (error != 0) {
3144 			if (ixa->ixa_ire != NULL &&
3145 			    (error == EHOSTUNREACH || error == ENETUNREACH)) {
3146 				/*
3147 				 * Let conn_ip_output/ire_send_noroute return
3148 				 * the error and send any local ICMP error.
3149 				 */
3150 				error = 0;
3151 			} else {
3152 				ixa_refrele(ixa);
3153 				iptun_drop_pkt(mp, &iptun->iptun_oerrors);
3154 				return;
3155 			}
3156 		}
3157 	}
3158 
3159 	iptun_output_common(iptun, ixa, mp);
3160 	ixa_refrele(ixa);
3161 }
3162 
3163 /*
3164  * We use an ixa based on the last destination.
3165  */
3166 static void
3167 iptun_output_6to4(iptun_t *iptun, mblk_t *mp)
3168 {
3169 	conn_t		*connp = iptun->iptun_connp;
3170 	ipha_t		*outer4, *inner4;
3171 	ip6_t		*outer6, *inner6;
3172 	ip_xmit_attr_t	*ixa;
3173 	ip_xmit_attr_t	*oldixa;
3174 	int		error;
3175 	boolean_t	need_connect;
3176 	in6_addr_t	v6dst;
3177 
3178 	ASSERT(mp->b_cont == NULL);	/* Verified by iptun_output */
3179 
3180 	/* Make sure we set ipha_dst before we look at ipha_dst */
3181 
3182 	(void) iptun_find_headers(mp, 0, &outer4, &inner4, &outer6, &inner6);
3183 	ASSERT(outer4 != NULL);
3184 	if (!iptun_out_process_6to4(iptun, outer4, inner6)) {
3185 		iptun_drop_pkt(mp, &iptun->iptun_oerrors);
3186 		return;
3187 	}
3188 
3189 	if (is_system_labeled()) {
3190 		/*
3191 		 * Since the label can be different meaning a potentially
3192 		 * different IRE,we always use a unique ip_xmit_attr_t.
3193 		 */
3194 		ixa = conn_get_ixa_exclusive(connp);
3195 	} else {
3196 		/*
3197 		 * If no other thread is using conn_ixa this just gets a
3198 		 * reference to conn_ixa. Otherwise we get a safe copy of
3199 		 * conn_ixa.
3200 		 */
3201 		ixa = conn_get_ixa(connp, B_FALSE);
3202 	}
3203 	if (ixa == NULL) {
3204 		iptun_drop_pkt(mp, &iptun->iptun_oerrors);
3205 		return;
3206 	}
3207 
3208 	mutex_enter(&connp->conn_lock);
3209 	if (connp->conn_v4lastdst == outer4->ipha_dst) {
3210 		need_connect = (ixa->ixa_ire == NULL);
3211 	} else {
3212 		/* In case previous destination was multirt */
3213 		ip_attr_newdst(ixa);
3214 
3215 		/*
3216 		 * We later update conn_ixa when we update conn_v4lastdst
3217 		 * which enables subsequent packets to avoid redoing
3218 		 * ip_attr_connect
3219 		 */
3220 		need_connect = B_TRUE;
3221 	}
3222 	mutex_exit(&connp->conn_lock);
3223 
3224 	/*
3225 	 * In case we got a safe copy of conn_ixa, or otherwise we don't
3226 	 * have a current ixa_ire, then we need to fill in any pointers in
3227 	 * the ixa.
3228 	 */
3229 	if (need_connect) {
3230 		IN6_IPADDR_TO_V4MAPPED(outer4->ipha_dst, &v6dst);
3231 
3232 		/* We handle IPsec in iptun_output_common */
3233 		error = ip_attr_connect(connp, ixa, &connp->conn_saddr_v6,
3234 		    &v6dst, &v6dst, 0, NULL, NULL, 0);
3235 		if (error != 0) {
3236 			if (ixa->ixa_ire != NULL &&
3237 			    (error == EHOSTUNREACH || error == ENETUNREACH)) {
3238 				/*
3239 				 * Let conn_ip_output/ire_send_noroute return
3240 				 * the error and send any local ICMP error.
3241 				 */
3242 				error = 0;
3243 			} else {
3244 				ixa_refrele(ixa);
3245 				iptun_drop_pkt(mp, &iptun->iptun_oerrors);
3246 				return;
3247 			}
3248 		}
3249 	}
3250 
3251 	iptun_output_common(iptun, ixa, mp);
3252 
3253 	/* Atomically replace conn_ixa and conn_v4lastdst */
3254 	mutex_enter(&connp->conn_lock);
3255 	if (connp->conn_v4lastdst != outer4->ipha_dst) {
3256 		/* Remember the dst which corresponds to conn_ixa */
3257 		connp->conn_v6lastdst = v6dst;
3258 		oldixa = conn_replace_ixa(connp, ixa);
3259 	} else {
3260 		oldixa = NULL;
3261 	}
3262 	mutex_exit(&connp->conn_lock);
3263 	ixa_refrele(ixa);
3264 	if (oldixa != NULL)
3265 		ixa_refrele(oldixa);
3266 }
3267 
3268 /*
3269  * Check the destination/label. Modifies *mpp by adding/removing CIPSO.
3270  *
3271  * We get the label from the message in order to honor the
3272  * ULPs/IPs choice of label. This will be NULL for forwarded
3273  * packets, neighbor discovery packets and some others.
3274  */
3275 static int
3276 iptun_output_check_label(mblk_t **mpp, ip_xmit_attr_t *ixa)
3277 {
3278 	cred_t	*cr;
3279 	int	adjust;
3280 	int	iplen;
3281 	int	err;
3282 	ts_label_t *effective_tsl = NULL;
3283 
3284 
3285 	ASSERT(is_system_labeled());
3286 
3287 	cr = msg_getcred(*mpp, NULL);
3288 	if (cr == NULL)
3289 		return (0);
3290 
3291 	/*
3292 	 * We need to start with a label based on the IP/ULP above us
3293 	 */
3294 	ip_xmit_attr_restore_tsl(ixa, cr);
3295 
3296 	/*
3297 	 * Need to update packet with any CIPSO option since
3298 	 * conn_ip_output doesn't do that.
3299 	 */
3300 	if (ixa->ixa_flags & IXAF_IS_IPV4) {
3301 		ipha_t *ipha;
3302 
3303 		ipha = (ipha_t *)(*mpp)->b_rptr;
3304 		iplen = ntohs(ipha->ipha_length);
3305 		err = tsol_check_label_v4(ixa->ixa_tsl,
3306 		    ixa->ixa_zoneid, mpp, CONN_MAC_DEFAULT, B_FALSE,
3307 		    ixa->ixa_ipst, &effective_tsl);
3308 		if (err != 0)
3309 			return (err);
3310 
3311 		ipha = (ipha_t *)(*mpp)->b_rptr;
3312 		adjust = (int)ntohs(ipha->ipha_length) - iplen;
3313 	} else {
3314 		ip6_t *ip6h;
3315 
3316 		ip6h = (ip6_t *)(*mpp)->b_rptr;
3317 		iplen = ntohs(ip6h->ip6_plen);
3318 
3319 		err = tsol_check_label_v6(ixa->ixa_tsl,
3320 		    ixa->ixa_zoneid, mpp, CONN_MAC_DEFAULT, B_FALSE,
3321 		    ixa->ixa_ipst, &effective_tsl);
3322 		if (err != 0)
3323 			return (err);
3324 
3325 		ip6h = (ip6_t *)(*mpp)->b_rptr;
3326 		adjust = (int)ntohs(ip6h->ip6_plen) - iplen;
3327 	}
3328 
3329 	if (effective_tsl != NULL) {
3330 		/* Update the label */
3331 		ip_xmit_attr_replace_tsl(ixa, effective_tsl);
3332 	}
3333 	ixa->ixa_pktlen += adjust;
3334 	ixa->ixa_ip_hdr_length += adjust;
3335 	return (0);
3336 }
3337 
3338 
3339 static void
3340 iptun_output_common(iptun_t *iptun, ip_xmit_attr_t *ixa, mblk_t *mp)
3341 {
3342 	ipsec_tun_pol_t	*itp = iptun->iptun_itp;
3343 	int		outer_hlen;
3344 	mblk_t		*newmp;
3345 	ipha_t		*outer4, *inner4;
3346 	ip6_t		*outer6, *inner6;
3347 	int		error;
3348 	boolean_t	update_pktlen;
3349 
3350 	ASSERT(ixa->ixa_ire != NULL);
3351 
3352 	outer_hlen = iptun_find_headers(mp, 0, &outer4, &inner4, &outer6,
3353 	    &inner6);
3354 	if (outer_hlen == 0) {
3355 		iptun_drop_pkt(mp, &iptun->iptun_oerrors);
3356 		return;
3357 	}
3358 
3359 	/* Save IXAF_DONTFRAG value */
3360 	iaflags_t dontfrag = ixa->ixa_flags & IXAF_DONTFRAG;
3361 
3362 	/* Perform header processing. */
3363 	if (outer4 != NULL) {
3364 		mp = iptun_out_process_ipv4(iptun, mp, outer4, inner4, inner6,
3365 		    ixa);
3366 	} else {
3367 		mp = iptun_out_process_ipv6(iptun, mp, outer6, inner4, inner6,
3368 		    ixa);
3369 	}
3370 	if (mp == NULL)
3371 		return;
3372 
3373 	/*
3374 	 * Let's hope the compiler optimizes this with "branch taken".
3375 	 */
3376 	if (itp != NULL && (itp->itp_flags & ITPF_P_ACTIVE)) {
3377 		/* This updates the ip_xmit_attr_t */
3378 		mp = ipsec_tun_outbound(mp, iptun, inner4, inner6, outer4,
3379 		    outer6, outer_hlen, ixa);
3380 		if (mp == NULL) {
3381 			atomic_inc_64(&iptun->iptun_oerrors);
3382 			return;
3383 		}
3384 		if (is_system_labeled()) {
3385 			/*
3386 			 * Might change the packet by adding/removing CIPSO.
3387 			 * After this caller inner* and outer* and outer_hlen
3388 			 * might be invalid.
3389 			 */
3390 			error = iptun_output_check_label(&mp, ixa);
3391 			if (error != 0) {
3392 				ip2dbg(("label check failed (%d)\n", error));
3393 				iptun_drop_pkt(mp, &iptun->iptun_oerrors);
3394 				return;
3395 			}
3396 		}
3397 
3398 		/*
3399 		 * ipsec_tun_outbound() returns a chain of tunneled IP
3400 		 * fragments linked with b_next (or a single message if the
3401 		 * tunneled packet wasn't a fragment).
3402 		 * If fragcache returned a list then we need to update
3403 		 * ixa_pktlen for all packets in the list.
3404 		 */
3405 		update_pktlen = (mp->b_next != NULL);
3406 
3407 		/*
3408 		 * Otherwise, we're good to go.  The ixa has been updated with
3409 		 * instructions for outbound IPsec processing.
3410 		 */
3411 		for (newmp = mp; newmp != NULL; newmp = mp) {
3412 			size_t minmtu = iptun->iptun_typeinfo->iti_minmtu;
3413 
3414 			atomic_inc_64(&iptun->iptun_opackets);
3415 			atomic_add_64(&iptun->iptun_obytes, ixa->ixa_pktlen);
3416 			mp = mp->b_next;
3417 			newmp->b_next = NULL;
3418 
3419 			/*
3420 			 * The IXAF_DONTFRAG flag is global, but there is
3421 			 * a chain here.  Check if we're really already
3422 			 * smaller than the minimum allowed MTU and reset here
3423 			 * appropriately.  Otherwise one small packet can kill
3424 			 * the whole chain's path mtu discovery.
3425 			 * In addition, update the pktlen to the length of
3426 			 * the actual packet being processed.
3427 			 */
3428 			if (update_pktlen) {
3429 				ixa->ixa_pktlen = msgdsize(newmp);
3430 				if (ixa->ixa_pktlen <= minmtu)
3431 					ixa->ixa_flags &= ~IXAF_DONTFRAG;
3432 			}
3433 
3434 			atomic_inc_64(&iptun->iptun_opackets);
3435 			atomic_add_64(&iptun->iptun_obytes, ixa->ixa_pktlen);
3436 
3437 			error = conn_ip_output(newmp, ixa);
3438 
3439 			/* Restore IXAF_DONTFRAG value */
3440 			ixa->ixa_flags |= dontfrag;
3441 
3442 			if (error == EMSGSIZE) {
3443 				/* IPsec policy might have changed */
3444 				(void) iptun_update_mtu(iptun, ixa, 0);
3445 			}
3446 		}
3447 	} else {
3448 		/*
3449 		 * The ip module will potentially apply global policy to the
3450 		 * packet in its output path if there's no active tunnel
3451 		 * policy.
3452 		 */
3453 		ASSERT(ixa->ixa_ipsec_policy == NULL);
3454 		mp = ip_output_attach_policy(mp, outer4, outer6, NULL, ixa);
3455 		if (mp == NULL) {
3456 			atomic_inc_64(&iptun->iptun_oerrors);
3457 			return;
3458 		}
3459 		if (is_system_labeled()) {
3460 			/*
3461 			 * Might change the packet by adding/removing CIPSO.
3462 			 * After this caller inner* and outer* and outer_hlen
3463 			 * might be invalid.
3464 			 */
3465 			error = iptun_output_check_label(&mp, ixa);
3466 			if (error != 0) {
3467 				ip2dbg(("label check failed (%d)\n", error));
3468 				iptun_drop_pkt(mp, &iptun->iptun_oerrors);
3469 				return;
3470 			}
3471 		}
3472 
3473 		atomic_inc_64(&iptun->iptun_opackets);
3474 		atomic_add_64(&iptun->iptun_obytes, ixa->ixa_pktlen);
3475 
3476 		error = conn_ip_output(mp, ixa);
3477 		if (error == EMSGSIZE) {
3478 			/* IPsec policy might have changed */
3479 			(void) iptun_update_mtu(iptun, ixa, 0);
3480 		}
3481 	}
3482 	if (ixa->ixa_flags & IXAF_IPSEC_SECURE)
3483 		ipsec_out_release_refs(ixa);
3484 }
3485 
3486 static mac_callbacks_t iptun_m_callbacks = {
3487 	.mc_callbacks	= (MC_SETPROP | MC_GETPROP | MC_PROPINFO),
3488 	.mc_getstat	= iptun_m_getstat,
3489 	.mc_start	= iptun_m_start,
3490 	.mc_stop	= iptun_m_stop,
3491 	.mc_setpromisc	= iptun_m_setpromisc,
3492 	.mc_multicst	= iptun_m_multicst,
3493 	.mc_unicst	= iptun_m_unicst,
3494 	.mc_tx		= iptun_m_tx,
3495 	.mc_reserved	= NULL,
3496 	.mc_setprop	= iptun_m_setprop,
3497 	.mc_getprop	= iptun_m_getprop,
3498 	.mc_propinfo	= iptun_m_propinfo
3499 };
3500