xref: /freebsd/sys/netinet6/ip6_input.c (revision b197d4b893974c9eb4d7b38704c6d5c486235d6f)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the project nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  *
31  *	$KAME: ip6_input.c,v 1.259 2002/01/21 04:58:09 jinmei Exp $
32  */
33 
34 /*-
35  * Copyright (c) 1982, 1986, 1988, 1993
36  *	The Regents of the University of California.  All rights reserved.
37  *
38  * Redistribution and use in source and binary forms, with or without
39  * modification, are permitted provided that the following conditions
40  * are met:
41  * 1. Redistributions of source code must retain the above copyright
42  *    notice, this list of conditions and the following disclaimer.
43  * 2. Redistributions in binary form must reproduce the above copyright
44  *    notice, this list of conditions and the following disclaimer in the
45  *    documentation and/or other materials provided with the distribution.
46  * 3. Neither the name of the University nor the names of its contributors
47  *    may be used to endorse or promote products derived from this software
48  *    without specific prior written permission.
49  *
50  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
51  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
52  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
53  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
54  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
55  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
56  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
57  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
58  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
59  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
60  * SUCH DAMAGE.
61  *
62  *	@(#)ip_input.c	8.2 (Berkeley) 1/4/94
63  */
64 
65 #include <sys/cdefs.h>
66 __FBSDID("$FreeBSD$");
67 
68 #include "opt_inet.h"
69 #include "opt_inet6.h"
70 #include "opt_ipsec.h"
71 #include "opt_route.h"
72 #include "opt_rss.h"
73 #include "opt_sctp.h"
74 
75 #include <sys/param.h>
76 #include <sys/systm.h>
77 #include <sys/hhook.h>
78 #include <sys/malloc.h>
79 #include <sys/mbuf.h>
80 #include <sys/proc.h>
81 #include <sys/domain.h>
82 #include <sys/protosw.h>
83 #include <sys/sdt.h>
84 #include <sys/socket.h>
85 #include <sys/socketvar.h>
86 #include <sys/errno.h>
87 #include <sys/time.h>
88 #include <sys/kernel.h>
89 #include <sys/lock.h>
90 #include <sys/rmlock.h>
91 #include <sys/syslog.h>
92 #include <sys/sysctl.h>
93 #include <sys/eventhandler.h>
94 
95 #include <net/if.h>
96 #include <net/if_var.h>
97 #include <net/if_types.h>
98 #include <net/if_dl.h>
99 #include <net/route.h>
100 #include <net/netisr.h>
101 #include <net/rss_config.h>
102 #include <net/pfil.h>
103 #include <net/vnet.h>
104 
105 #include <netinet/in.h>
106 #include <netinet/in_kdtrace.h>
107 #include <netinet/ip_var.h>
108 #include <netinet/in_systm.h>
109 #include <net/if_llatbl.h>
110 #ifdef INET
111 #include <netinet/ip.h>
112 #include <netinet/ip_icmp.h>
113 #endif /* INET */
114 #include <netinet/ip6.h>
115 #include <netinet6/in6_var.h>
116 #include <netinet6/ip6_var.h>
117 #include <netinet/ip_encap.h>
118 #include <netinet/in_pcb.h>
119 #include <netinet/icmp6.h>
120 #include <netinet6/scope6_var.h>
121 #include <netinet6/in6_ifattach.h>
122 #include <netinet6/mld6_var.h>
123 #include <netinet6/nd6.h>
124 #include <netinet6/in6_rss.h>
125 #ifdef SCTP
126 #include <netinet/sctp_pcb.h>
127 #include <netinet6/sctp6_var.h>
128 #endif
129 
130 #include <netipsec/ipsec_support.h>
131 
132 #include <netinet6/ip6protosw.h>
133 
134 ipproto_input_t		*ip6_protox[IPPROTO_MAX] = {
135 			    [0 ... IPPROTO_MAX - 1] = rip6_input };
136 ipproto_ctlinput_t	*ip6_ctlprotox[IPPROTO_MAX] = {
137 			    [0 ... IPPROTO_MAX - 1] = rip6_ctlinput };
138 
139 VNET_DEFINE(struct in6_ifaddrhead, in6_ifaddrhead);
140 VNET_DEFINE(struct in6_ifaddrlisthead *, in6_ifaddrhashtbl);
141 VNET_DEFINE(u_long, in6_ifaddrhmask);
142 
143 static struct netisr_handler ip6_nh = {
144 	.nh_name = "ip6",
145 	.nh_handler = ip6_input,
146 	.nh_proto = NETISR_IPV6,
147 #ifdef RSS
148 	.nh_m2cpuid = rss_soft_m2cpuid_v6,
149 	.nh_policy = NETISR_POLICY_CPU,
150 	.nh_dispatch = NETISR_DISPATCH_HYBRID,
151 #else
152 	.nh_policy = NETISR_POLICY_FLOW,
153 #endif
154 };
155 
156 static int
157 sysctl_netinet6_intr_queue_maxlen(SYSCTL_HANDLER_ARGS)
158 {
159 	int error, qlimit;
160 
161 	netisr_getqlimit(&ip6_nh, &qlimit);
162 	error = sysctl_handle_int(oidp, &qlimit, 0, req);
163 	if (error || !req->newptr)
164 		return (error);
165 	if (qlimit < 1)
166 		return (EINVAL);
167 	return (netisr_setqlimit(&ip6_nh, qlimit));
168 }
169 SYSCTL_DECL(_net_inet6_ip6);
170 SYSCTL_PROC(_net_inet6_ip6, IPV6CTL_INTRQMAXLEN, intr_queue_maxlen,
171     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
172     0, 0, sysctl_netinet6_intr_queue_maxlen, "I",
173     "Maximum size of the IPv6 input queue");
174 
175 VNET_DEFINE_STATIC(bool, ip6_sav) = true;
176 #define	V_ip6_sav	VNET(ip6_sav)
177 SYSCTL_BOOL(_net_inet6_ip6, OID_AUTO, source_address_validation,
178     CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ip6_sav), true,
179     "Drop incoming packets with source address that is a local address");
180 
181 #ifdef RSS
182 static struct netisr_handler ip6_direct_nh = {
183 	.nh_name = "ip6_direct",
184 	.nh_handler = ip6_direct_input,
185 	.nh_proto = NETISR_IPV6_DIRECT,
186 	.nh_m2cpuid = rss_soft_m2cpuid_v6,
187 	.nh_policy = NETISR_POLICY_CPU,
188 	.nh_dispatch = NETISR_DISPATCH_HYBRID,
189 };
190 
191 static int
192 sysctl_netinet6_intr_direct_queue_maxlen(SYSCTL_HANDLER_ARGS)
193 {
194 	int error, qlimit;
195 
196 	netisr_getqlimit(&ip6_direct_nh, &qlimit);
197 	error = sysctl_handle_int(oidp, &qlimit, 0, req);
198 	if (error || !req->newptr)
199 		return (error);
200 	if (qlimit < 1)
201 		return (EINVAL);
202 	return (netisr_setqlimit(&ip6_direct_nh, qlimit));
203 }
204 SYSCTL_PROC(_net_inet6_ip6, IPV6CTL_INTRDQMAXLEN, intr_direct_queue_maxlen,
205     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
206     0, 0, sysctl_netinet6_intr_direct_queue_maxlen, "I",
207     "Maximum size of the IPv6 direct input queue");
208 
209 #endif
210 
211 VNET_DEFINE(pfil_head_t, inet6_pfil_head);
212 
213 VNET_PCPUSTAT_DEFINE(struct ip6stat, ip6stat);
214 VNET_PCPUSTAT_SYSINIT(ip6stat);
215 #ifdef VIMAGE
216 VNET_PCPUSTAT_SYSUNINIT(ip6stat);
217 #endif /* VIMAGE */
218 
219 struct rmlock in6_ifaddr_lock;
220 RM_SYSINIT(in6_ifaddr_lock, &in6_ifaddr_lock, "in6_ifaddr_lock");
221 
222 static int ip6_hopopts_input(u_int32_t *, u_int32_t *, struct mbuf **, int *);
223 
224 /*
225  * IP6 initialization: fill in IP6 protocol switch table.
226  * All protocols not implemented in kernel go to raw IP6 protocol handler.
227  */
228 static void
229 ip6_vnet_init(void *arg __unused)
230 {
231 	struct pfil_head_args args;
232 
233 	TUNABLE_INT_FETCH("net.inet6.ip6.auto_linklocal",
234 	    &V_ip6_auto_linklocal);
235 	TUNABLE_INT_FETCH("net.inet6.ip6.accept_rtadv", &V_ip6_accept_rtadv);
236 	TUNABLE_INT_FETCH("net.inet6.ip6.no_radr", &V_ip6_no_radr);
237 
238 	CK_STAILQ_INIT(&V_in6_ifaddrhead);
239 	V_in6_ifaddrhashtbl = hashinit(IN6ADDR_NHASH, M_IFADDR,
240 	    &V_in6_ifaddrhmask);
241 
242 	/* Initialize packet filter hooks. */
243 	args.pa_version = PFIL_VERSION;
244 	args.pa_flags = PFIL_IN | PFIL_OUT;
245 	args.pa_type = PFIL_TYPE_IP6;
246 	args.pa_headname = PFIL_INET6_NAME;
247 	V_inet6_pfil_head = pfil_head_register(&args);
248 
249 	if (hhook_head_register(HHOOK_TYPE_IPSEC_IN, AF_INET6,
250 	    &V_ipsec_hhh_in[HHOOK_IPSEC_INET6],
251 	    HHOOK_WAITOK | HHOOK_HEADISINVNET) != 0)
252 		printf("%s: WARNING: unable to register input helper hook\n",
253 		    __func__);
254 	if (hhook_head_register(HHOOK_TYPE_IPSEC_OUT, AF_INET6,
255 	    &V_ipsec_hhh_out[HHOOK_IPSEC_INET6],
256 	    HHOOK_WAITOK | HHOOK_HEADISINVNET) != 0)
257 		printf("%s: WARNING: unable to register output helper hook\n",
258 		    __func__);
259 
260 	scope6_init();
261 	addrsel_policy_init();
262 	nd6_init();
263 	frag6_init();
264 
265 	V_ip6_desync_factor = arc4random() % MAX_TEMP_DESYNC_FACTOR;
266 
267 	/* Skip global initialization stuff for non-default instances. */
268 #ifdef VIMAGE
269 	netisr_register_vnet(&ip6_nh);
270 #ifdef RSS
271 	netisr_register_vnet(&ip6_direct_nh);
272 #endif
273 #endif
274 }
275 VNET_SYSINIT(ip6_vnet_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_FOURTH,
276     ip6_vnet_init, NULL);
277 
278 static void
279 ip6_init(void *arg __unused)
280 {
281 
282 	/*
283 	 * Register statically those protocols that are unlikely to ever go
284 	 * dynamic.
285 	 */
286 	IP6PROTO_REGISTER(IPPROTO_ICMPV6, icmp6_input, rip6_ctlinput);
287 	IP6PROTO_REGISTER(IPPROTO_DSTOPTS, dest6_input, NULL);
288 	IP6PROTO_REGISTER(IPPROTO_ROUTING, route6_input, NULL);
289 	IP6PROTO_REGISTER(IPPROTO_FRAGMENT, frag6_input, NULL);
290 	IP6PROTO_REGISTER(IPPROTO_IPV4, encap6_input, NULL);
291 	IP6PROTO_REGISTER(IPPROTO_IPV6, encap6_input, NULL);
292 	IP6PROTO_REGISTER(IPPROTO_ETHERIP, encap6_input, NULL);
293 	IP6PROTO_REGISTER(IPPROTO_GRE, encap6_input, NULL);
294 	IP6PROTO_REGISTER(IPPROTO_PIM, encap6_input, NULL);
295 #ifdef SCTP	/* XXX: has a loadable & static version */
296 	IP6PROTO_REGISTER(IPPROTO_SCTP, sctp6_input, sctp6_ctlinput);
297 #endif
298 
299 	EVENTHANDLER_REGISTER(vm_lowmem, frag6_drain, NULL, LOWMEM_PRI_DEFAULT);
300 	EVENTHANDLER_REGISTER(mbuf_lowmem, frag6_drain, NULL,
301 	    LOWMEM_PRI_DEFAULT);
302 
303 	netisr_register(&ip6_nh);
304 #ifdef RSS
305 	netisr_register(&ip6_direct_nh);
306 #endif
307 }
308 SYSINIT(ip6_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD, ip6_init, NULL);
309 
310 int
311 ip6proto_register(uint8_t proto, ipproto_input_t input, ipproto_ctlinput_t ctl)
312 {
313 
314 	MPASS(proto > 0);
315 
316 	if (ip6_protox[proto] == rip6_input) {
317 		ip6_protox[proto] = input;
318 		ip6_ctlprotox[proto] = ctl;
319 		return (0);
320 	} else
321 		return (EEXIST);
322 }
323 
324 int
325 ip6proto_unregister(uint8_t proto)
326 {
327 
328 	MPASS(proto > 0);
329 
330 	if (ip6_protox[proto] != rip6_input) {
331 		ip6_protox[proto] = rip6_input;
332 		ip6_ctlprotox[proto] = rip6_ctlinput;
333 		return (0);
334 	} else
335 		return (ENOENT);
336 }
337 
338 #ifdef VIMAGE
339 static void
340 ip6_destroy(void *unused __unused)
341 {
342 	struct ifaddr *ifa, *nifa;
343 	struct ifnet *ifp;
344 	int error;
345 
346 #ifdef RSS
347 	netisr_unregister_vnet(&ip6_direct_nh);
348 #endif
349 	netisr_unregister_vnet(&ip6_nh);
350 
351 	pfil_head_unregister(V_inet6_pfil_head);
352 	error = hhook_head_deregister(V_ipsec_hhh_in[HHOOK_IPSEC_INET6]);
353 	if (error != 0) {
354 		printf("%s: WARNING: unable to deregister input helper hook "
355 		    "type HHOOK_TYPE_IPSEC_IN, id HHOOK_IPSEC_INET6: "
356 		    "error %d returned\n", __func__, error);
357 	}
358 	error = hhook_head_deregister(V_ipsec_hhh_out[HHOOK_IPSEC_INET6]);
359 	if (error != 0) {
360 		printf("%s: WARNING: unable to deregister output helper hook "
361 		    "type HHOOK_TYPE_IPSEC_OUT, id HHOOK_IPSEC_INET6: "
362 		    "error %d returned\n", __func__, error);
363 	}
364 
365 	/* Cleanup addresses. */
366 	IFNET_RLOCK();
367 	CK_STAILQ_FOREACH(ifp, &V_ifnet, if_link) {
368 		/* Cannot lock here - lock recursion. */
369 		/* IF_ADDR_LOCK(ifp); */
370 		CK_STAILQ_FOREACH_SAFE(ifa, &ifp->if_addrhead, ifa_link, nifa) {
371 			if (ifa->ifa_addr->sa_family != AF_INET6)
372 				continue;
373 			in6_purgeaddr(ifa);
374 		}
375 		/* IF_ADDR_UNLOCK(ifp); */
376 		in6_ifdetach_destroy(ifp);
377 		mld_domifdetach(ifp);
378 	}
379 	IFNET_RUNLOCK();
380 
381 	/* Make sure any routes are gone as well. */
382 	rib_flush_routes_family(AF_INET6);
383 
384 	frag6_destroy();
385 	nd6_destroy();
386 	in6_ifattach_destroy();
387 
388 	hashdestroy(V_in6_ifaddrhashtbl, M_IFADDR, V_in6_ifaddrhmask);
389 }
390 
391 VNET_SYSUNINIT(inet6, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD, ip6_destroy, NULL);
392 #endif
393 
394 static int
395 ip6_input_hbh(struct mbuf **mp, uint32_t *plen, uint32_t *rtalert, int *off,
396     int *nxt, int *ours)
397 {
398 	struct mbuf *m;
399 	struct ip6_hdr *ip6;
400 	struct ip6_hbh *hbh;
401 
402 	if (ip6_hopopts_input(plen, rtalert, mp, off)) {
403 #if 0	/*touches NULL pointer*/
404 		in6_ifstat_inc((*mp)->m_pkthdr.rcvif, ifs6_in_discard);
405 #endif
406 		goto out;	/* m have already been freed */
407 	}
408 
409 	/* adjust pointer */
410 	m = *mp;
411 	ip6 = mtod(m, struct ip6_hdr *);
412 
413 	/*
414 	 * if the payload length field is 0 and the next header field
415 	 * indicates Hop-by-Hop Options header, then a Jumbo Payload
416 	 * option MUST be included.
417 	 */
418 	if (ip6->ip6_plen == 0 && *plen == 0) {
419 		/*
420 		 * Note that if a valid jumbo payload option is
421 		 * contained, ip6_hopopts_input() must set a valid
422 		 * (non-zero) payload length to the variable plen.
423 		 */
424 		IP6STAT_INC(ip6s_badoptions);
425 		in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
426 		in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_hdrerr);
427 		icmp6_error(m, ICMP6_PARAM_PROB,
428 			    ICMP6_PARAMPROB_HEADER,
429 			    (caddr_t)&ip6->ip6_plen - (caddr_t)ip6);
430 		goto out;
431 	}
432 	/* ip6_hopopts_input() ensures that mbuf is contiguous */
433 	hbh = (struct ip6_hbh *)(ip6 + 1);
434 	*nxt = hbh->ip6h_nxt;
435 
436 	/*
437 	 * If we are acting as a router and the packet contains a
438 	 * router alert option, see if we know the option value.
439 	 * Currently, we only support the option value for MLD, in which
440 	 * case we should pass the packet to the multicast routing
441 	 * daemon.
442 	 */
443 	if (*rtalert != ~0) {
444 		switch (*rtalert) {
445 		case IP6OPT_RTALERT_MLD:
446 			if (V_ip6_forwarding)
447 				*ours = 1;
448 			break;
449 		default:
450 			/*
451 			 * RFC2711 requires unrecognized values must be
452 			 * silently ignored.
453 			 */
454 			break;
455 		}
456 	}
457 
458 	return (0);
459 
460 out:
461 	return (1);
462 }
463 
464 #ifdef RSS
465 /*
466  * IPv6 direct input routine.
467  *
468  * This is called when reinjecting completed fragments where
469  * all of the previous checking and book-keeping has been done.
470  */
471 void
472 ip6_direct_input(struct mbuf *m)
473 {
474 	int off, nxt;
475 	int nest;
476 	struct m_tag *mtag;
477 	struct ip6_direct_ctx *ip6dc;
478 
479 	mtag = m_tag_locate(m, MTAG_ABI_IPV6, IPV6_TAG_DIRECT, NULL);
480 	KASSERT(mtag != NULL, ("Reinjected packet w/o direct ctx tag!"));
481 
482 	ip6dc = (struct ip6_direct_ctx *)(mtag + 1);
483 	nxt = ip6dc->ip6dc_nxt;
484 	off = ip6dc->ip6dc_off;
485 
486 	nest = 0;
487 
488 	m_tag_delete(m, mtag);
489 
490 	while (nxt != IPPROTO_DONE) {
491 		if (V_ip6_hdrnestlimit && (++nest > V_ip6_hdrnestlimit)) {
492 			IP6STAT_INC(ip6s_toomanyhdr);
493 			goto bad;
494 		}
495 
496 		/*
497 		 * protection against faulty packet - there should be
498 		 * more sanity checks in header chain processing.
499 		 */
500 		if (m->m_pkthdr.len < off) {
501 			IP6STAT_INC(ip6s_tooshort);
502 			in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_truncated);
503 			goto bad;
504 		}
505 
506 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
507 		if (IPSEC_ENABLED(ipv6)) {
508 			if (IPSEC_INPUT(ipv6, m, off, nxt) != 0)
509 				return;
510 		}
511 #endif /* IPSEC */
512 
513 		nxt = ip6_protox[nxt](&m, &off, nxt);
514 	}
515 	return;
516 bad:
517 	m_freem(m);
518 }
519 #endif
520 
521 void
522 ip6_input(struct mbuf *m)
523 {
524 	struct in6_addr odst;
525 	struct ip6_hdr *ip6;
526 	struct in6_ifaddr *ia;
527 	struct ifnet *rcvif;
528 	u_int32_t plen;
529 	u_int32_t rtalert = ~0;
530 	int off = sizeof(struct ip6_hdr), nest;
531 	int nxt, ours = 0;
532 	int srcrt = 0;
533 
534 	/*
535 	 * Drop the packet if IPv6 operation is disabled on the interface.
536 	 */
537 	rcvif = m->m_pkthdr.rcvif;
538 	if ((ND_IFINFO(rcvif)->flags & ND6_IFF_IFDISABLED))
539 		goto bad;
540 
541 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
542 	/*
543 	 * should the inner packet be considered authentic?
544 	 * see comment in ah4_input().
545 	 * NB: m cannot be NULL when passed to the input routine
546 	 */
547 
548 	m->m_flags &= ~M_AUTHIPHDR;
549 	m->m_flags &= ~M_AUTHIPDGM;
550 
551 #endif /* IPSEC */
552 
553 	if (m->m_flags & M_FASTFWD_OURS) {
554 		/*
555 		 * Firewall changed destination to local.
556 		 */
557 		ip6 = mtod(m, struct ip6_hdr *);
558 		goto passin;
559 	}
560 
561 	/*
562 	 * mbuf statistics
563 	 */
564 	if (m->m_flags & M_EXT) {
565 		if (m->m_next)
566 			IP6STAT_INC(ip6s_mext2m);
567 		else
568 			IP6STAT_INC(ip6s_mext1);
569 	} else {
570 		if (m->m_next) {
571 			struct ifnet *ifp = (m->m_flags & M_LOOP) ? V_loif : rcvif;
572 			int ifindex = ifp->if_index;
573 			if (ifindex >= IP6S_M2MMAX)
574 				ifindex = 0;
575 			IP6STAT_INC(ip6s_m2m[ifindex]);
576 		} else
577 			IP6STAT_INC(ip6s_m1);
578 	}
579 
580 	in6_ifstat_inc(rcvif, ifs6_in_receive);
581 	IP6STAT_INC(ip6s_total);
582 
583 	/*
584 	 * L2 bridge code and some other code can return mbuf chain
585 	 * that does not conform to KAME requirement.  too bad.
586 	 * XXX: fails to join if interface MTU > MCLBYTES.  jumbogram?
587 	 */
588 	if (m && m->m_next != NULL && m->m_pkthdr.len < MCLBYTES) {
589 		struct mbuf *n;
590 
591 		if (m->m_pkthdr.len > MHLEN)
592 			n = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
593 		else
594 			n = m_gethdr(M_NOWAIT, MT_DATA);
595 		if (n == NULL)
596 			goto bad;
597 
598 		m_move_pkthdr(n, m);
599 		m_copydata(m, 0, n->m_pkthdr.len, mtod(n, caddr_t));
600 		n->m_len = n->m_pkthdr.len;
601 		m_freem(m);
602 		m = n;
603 	}
604 	if (m->m_len < sizeof(struct ip6_hdr)) {
605 		if ((m = m_pullup(m, sizeof(struct ip6_hdr))) == NULL) {
606 			IP6STAT_INC(ip6s_toosmall);
607 			in6_ifstat_inc(rcvif, ifs6_in_hdrerr);
608 			goto bad;
609 		}
610 	}
611 
612 	ip6 = mtod(m, struct ip6_hdr *);
613 	if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) {
614 		IP6STAT_INC(ip6s_badvers);
615 		in6_ifstat_inc(rcvif, ifs6_in_hdrerr);
616 		goto bad;
617 	}
618 
619 	IP6STAT_INC(ip6s_nxthist[ip6->ip6_nxt]);
620 	IP_PROBE(receive, NULL, NULL, ip6, rcvif, NULL, ip6);
621 
622 	/*
623 	 * Check against address spoofing/corruption.
624 	 */
625 	if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_src) ||
626 	    IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_dst)) {
627 		/*
628 		 * XXX: "badscope" is not very suitable for a multicast source.
629 		 */
630 		IP6STAT_INC(ip6s_badscope);
631 		in6_ifstat_inc(rcvif, ifs6_in_addrerr);
632 		goto bad;
633 	}
634 	if (IN6_IS_ADDR_MC_INTFACELOCAL(&ip6->ip6_dst) &&
635 	    !(m->m_flags & M_LOOP)) {
636 		/*
637 		 * In this case, the packet should come from the loopback
638 		 * interface.  However, we cannot just check the if_flags,
639 		 * because ip6_mloopback() passes the "actual" interface
640 		 * as the outgoing/incoming interface.
641 		 */
642 		IP6STAT_INC(ip6s_badscope);
643 		in6_ifstat_inc(rcvif, ifs6_in_addrerr);
644 		goto bad;
645 	}
646 	if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) &&
647 	    IPV6_ADDR_MC_SCOPE(&ip6->ip6_dst) == 0) {
648 		/*
649 		 * RFC4291 2.7:
650 		 * Nodes must not originate a packet to a multicast address
651 		 * whose scop field contains the reserved value 0; if such
652 		 * a packet is received, it must be silently dropped.
653 		 */
654 		IP6STAT_INC(ip6s_badscope);
655 		in6_ifstat_inc(rcvif, ifs6_in_addrerr);
656 		goto bad;
657 	}
658 #ifdef ALTQ
659 	if (altq_input != NULL && (*altq_input)(m, AF_INET6) == 0) {
660 		/* packet is dropped by traffic conditioner */
661 		return;
662 	}
663 #endif
664 	/*
665 	 * The following check is not documented in specs.  A malicious
666 	 * party may be able to use IPv4 mapped addr to confuse tcp/udp stack
667 	 * and bypass security checks (act as if it was from 127.0.0.1 by using
668 	 * IPv6 src ::ffff:127.0.0.1).  Be cautious.
669 	 *
670 	 * We have supported IPv6-only kernels for a few years and this issue
671 	 * has not come up.  The world seems to move mostly towards not using
672 	 * v4mapped on the wire, so it makes sense for us to keep rejecting
673 	 * any such packets.
674 	 */
675 	if (IN6_IS_ADDR_V4MAPPED(&ip6->ip6_src) ||
676 	    IN6_IS_ADDR_V4MAPPED(&ip6->ip6_dst)) {
677 		IP6STAT_INC(ip6s_badscope);
678 		in6_ifstat_inc(rcvif, ifs6_in_addrerr);
679 		goto bad;
680 	}
681 #if 0
682 	/*
683 	 * Reject packets with IPv4 compatible addresses (auto tunnel).
684 	 *
685 	 * The code forbids auto tunnel relay case in RFC1933 (the check is
686 	 * stronger than RFC1933).  We may want to re-enable it if mech-xx
687 	 * is revised to forbid relaying case.
688 	 */
689 	if (IN6_IS_ADDR_V4COMPAT(&ip6->ip6_src) ||
690 	    IN6_IS_ADDR_V4COMPAT(&ip6->ip6_dst)) {
691 		IP6STAT_INC(ip6s_badscope);
692 		in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
693 		goto bad;
694 	}
695 #endif
696 	/*
697 	 * Try to forward the packet, but if we fail continue.
698 	 * ip6_tryforward() does not generate redirects, so fall
699 	 * through to normal processing if redirects are required.
700 	 * ip6_tryforward() does inbound and outbound packet firewall
701 	 * processing. If firewall has decided that destination becomes
702 	 * our local address, it sets M_FASTFWD_OURS flag. In this
703 	 * case skip another inbound firewall processing and update
704 	 * ip6 pointer.
705 	 */
706 	if (V_ip6_forwarding != 0 && V_ip6_sendredirects == 0
707 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
708 	    && (!IPSEC_ENABLED(ipv6) ||
709 	    IPSEC_CAPS(ipv6, m, IPSEC_CAP_OPERABLE) == 0)
710 #endif
711 	    ) {
712 		if ((m = ip6_tryforward(m)) == NULL)
713 			return;
714 		if (m->m_flags & M_FASTFWD_OURS) {
715 			ip6 = mtod(m, struct ip6_hdr *);
716 			goto passin;
717 		}
718 	}
719 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
720 	/*
721 	 * Bypass packet filtering for packets previously handled by IPsec.
722 	 */
723 	if (IPSEC_ENABLED(ipv6) &&
724 	    IPSEC_CAPS(ipv6, m, IPSEC_CAP_BYPASS_FILTER) != 0)
725 			goto passin;
726 #endif
727 	/*
728 	 * Run through list of hooks for input packets.
729 	 *
730 	 * NB: Beware of the destination address changing
731 	 *     (e.g. by NAT rewriting).  When this happens,
732 	 *     tell ip6_forward to do the right thing.
733 	 */
734 
735 	/* Jump over all PFIL processing if hooks are not active. */
736 	if (!PFIL_HOOKED_IN(V_inet6_pfil_head))
737 		goto passin;
738 
739 	odst = ip6->ip6_dst;
740 	if (pfil_run_hooks(V_inet6_pfil_head, &m, m->m_pkthdr.rcvif, PFIL_IN,
741 	    NULL) != PFIL_PASS)
742 		return;
743 	ip6 = mtod(m, struct ip6_hdr *);
744 	srcrt = !IN6_ARE_ADDR_EQUAL(&odst, &ip6->ip6_dst);
745 	if ((m->m_flags & (M_IP6_NEXTHOP | M_FASTFWD_OURS)) == M_IP6_NEXTHOP &&
746 	    m_tag_find(m, PACKET_TAG_IPFORWARD, NULL) != NULL) {
747 		/*
748 		 * Directly ship the packet on.  This allows forwarding
749 		 * packets originally destined to us to some other directly
750 		 * connected host.
751 		 */
752 		ip6_forward(m, 1);
753 		return;
754 	}
755 
756 passin:
757 	/*
758 	 * Disambiguate address scope zones (if there is ambiguity).
759 	 * We first make sure that the original source or destination address
760 	 * is not in our internal form for scoped addresses.  Such addresses
761 	 * are not necessarily invalid spec-wise, but we cannot accept them due
762 	 * to the usage conflict.
763 	 * in6_setscope() then also checks and rejects the cases where src or
764 	 * dst are the loopback address and the receiving interface
765 	 * is not loopback.
766 	 */
767 	if (in6_clearscope(&ip6->ip6_src) || in6_clearscope(&ip6->ip6_dst)) {
768 		IP6STAT_INC(ip6s_badscope); /* XXX */
769 		goto bad;
770 	}
771 	if (in6_setscope(&ip6->ip6_src, rcvif, NULL) ||
772 	    in6_setscope(&ip6->ip6_dst, rcvif, NULL)) {
773 		IP6STAT_INC(ip6s_badscope);
774 		goto bad;
775 	}
776 	if (m->m_flags & M_FASTFWD_OURS) {
777 		m->m_flags &= ~M_FASTFWD_OURS;
778 		ours = 1;
779 		goto hbhcheck;
780 	}
781 	/*
782 	 * Multicast check. Assume packet is for us to avoid
783 	 * prematurely taking locks.
784 	 */
785 	if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
786 		ours = 1;
787 		in6_ifstat_inc(rcvif, ifs6_in_mcast);
788 		goto hbhcheck;
789 	}
790 	/*
791 	 * Unicast check
792 	 * XXX: For now we keep link-local IPv6 addresses with embedded
793 	 *      scope zone id, therefore we use zero zoneid here.
794 	 */
795 	ia = in6ifa_ifwithaddr(&ip6->ip6_dst, 0 /* XXX */, false);
796 	if (ia != NULL) {
797 		if (ia->ia6_flags & IN6_IFF_NOTREADY) {
798 			char ip6bufs[INET6_ADDRSTRLEN];
799 			char ip6bufd[INET6_ADDRSTRLEN];
800 			/* address is not ready, so discard the packet. */
801 			nd6log((LOG_INFO,
802 			    "ip6_input: packet to an unready address %s->%s\n",
803 			    ip6_sprintf(ip6bufs, &ip6->ip6_src),
804 			    ip6_sprintf(ip6bufd, &ip6->ip6_dst)));
805 			goto bad;
806 		}
807 		if (V_ip6_sav && !(m->m_flags & M_LOOP) &&
808 		    __predict_false(in6_localip_fib(&ip6->ip6_src,
809 			    rcvif->if_fib))) {
810 			IP6STAT_INC(ip6s_badscope); /* XXX */
811 			goto bad;
812 		}
813 		/* Count the packet in the ip address stats */
814 		counter_u64_add(ia->ia_ifa.ifa_ipackets, 1);
815 		counter_u64_add(ia->ia_ifa.ifa_ibytes, m->m_pkthdr.len);
816 		ours = 1;
817 		goto hbhcheck;
818 	}
819 
820 	/*
821 	 * Now there is no reason to process the packet if it's not our own
822 	 * and we're not a router.
823 	 */
824 	if (!V_ip6_forwarding) {
825 		IP6STAT_INC(ip6s_cantforward);
826 		goto bad;
827 	}
828 
829   hbhcheck:
830 	/*
831 	 * Process Hop-by-Hop options header if it's contained.
832 	 * m may be modified in ip6_hopopts_input().
833 	 * If a JumboPayload option is included, plen will also be modified.
834 	 */
835 	plen = (u_int32_t)ntohs(ip6->ip6_plen);
836 	if (ip6->ip6_nxt == IPPROTO_HOPOPTS) {
837 		if (ip6_input_hbh(&m, &plen, &rtalert, &off, &nxt, &ours) != 0)
838 			return;
839 	} else
840 		nxt = ip6->ip6_nxt;
841 
842 	/*
843 	 * Use mbuf flags to propagate Router Alert option to
844 	 * ICMPv6 layer, as hop-by-hop options have been stripped.
845 	 */
846 	if (rtalert != ~0)
847 		m->m_flags |= M_RTALERT_MLD;
848 
849 	/*
850 	 * Check that the amount of data in the buffers
851 	 * is as at least much as the IPv6 header would have us expect.
852 	 * Trim mbufs if longer than we expect.
853 	 * Drop packet if shorter than we expect.
854 	 */
855 	if (m->m_pkthdr.len - sizeof(struct ip6_hdr) < plen) {
856 		IP6STAT_INC(ip6s_tooshort);
857 		in6_ifstat_inc(rcvif, ifs6_in_truncated);
858 		goto bad;
859 	}
860 	if (m->m_pkthdr.len > sizeof(struct ip6_hdr) + plen) {
861 		if (m->m_len == m->m_pkthdr.len) {
862 			m->m_len = sizeof(struct ip6_hdr) + plen;
863 			m->m_pkthdr.len = sizeof(struct ip6_hdr) + plen;
864 		} else
865 			m_adj(m, sizeof(struct ip6_hdr) + plen - m->m_pkthdr.len);
866 	}
867 
868 	/*
869 	 * Forward if desirable.
870 	 */
871 	if (V_ip6_mrouter &&
872 	    IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
873 		/*
874 		 * If we are acting as a multicast router, all
875 		 * incoming multicast packets are passed to the
876 		 * kernel-level multicast forwarding function.
877 		 * The packet is returned (relatively) intact; if
878 		 * ip6_mforward() returns a non-zero value, the packet
879 		 * must be discarded, else it may be accepted below.
880 		 *
881 		 * XXX TODO: Check hlim and multicast scope here to avoid
882 		 * unnecessarily calling into ip6_mforward().
883 		 */
884 		if (ip6_mforward && ip6_mforward(ip6, rcvif, m)) {
885 			IP6STAT_INC(ip6s_cantforward);
886 			goto bad;
887 		}
888 	} else if (!ours) {
889 		ip6_forward(m, srcrt);
890 		return;
891 	}
892 
893 	/*
894 	 * Tell launch routine the next header
895 	 */
896 	IP6STAT_INC(ip6s_delivered);
897 	in6_ifstat_inc(rcvif, ifs6_in_deliver);
898 	nest = 0;
899 
900 	while (nxt != IPPROTO_DONE) {
901 		if (V_ip6_hdrnestlimit && (++nest > V_ip6_hdrnestlimit)) {
902 			IP6STAT_INC(ip6s_toomanyhdr);
903 			goto bad;
904 		}
905 
906 		/*
907 		 * protection against faulty packet - there should be
908 		 * more sanity checks in header chain processing.
909 		 */
910 		if (m->m_pkthdr.len < off) {
911 			IP6STAT_INC(ip6s_tooshort);
912 			in6_ifstat_inc(rcvif, ifs6_in_truncated);
913 			goto bad;
914 		}
915 
916 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
917 		if (IPSEC_ENABLED(ipv6)) {
918 			if (IPSEC_INPUT(ipv6, m, off, nxt) != 0)
919 				return;
920 		}
921 #endif /* IPSEC */
922 
923 		nxt = ip6_protox[nxt](&m, &off, nxt);
924 	}
925 	return;
926 bad:
927 	in6_ifstat_inc(rcvif, ifs6_in_discard);
928 	if (m != NULL)
929 		m_freem(m);
930 }
931 
932 /*
933  * Hop-by-Hop options header processing. If a valid jumbo payload option is
934  * included, the real payload length will be stored in plenp.
935  *
936  * rtalertp - XXX: should be stored more smart way
937  */
938 static int
939 ip6_hopopts_input(u_int32_t *plenp, u_int32_t *rtalertp,
940     struct mbuf **mp, int *offp)
941 {
942 	struct mbuf *m = *mp;
943 	int off = *offp, hbhlen;
944 	struct ip6_hbh *hbh;
945 
946 	/* validation of the length of the header */
947 	if (m->m_len < off + sizeof(*hbh)) {
948 		m = m_pullup(m, off + sizeof(*hbh));
949 		if (m == NULL) {
950 			IP6STAT_INC(ip6s_exthdrtoolong);
951 			*mp = NULL;
952 			return (-1);
953 		}
954 	}
955 	hbh = (struct ip6_hbh *)(mtod(m, caddr_t) + off);
956 	hbhlen = (hbh->ip6h_len + 1) << 3;
957 
958 	if (m->m_len < off + hbhlen) {
959 		m = m_pullup(m, off + hbhlen);
960 		if (m == NULL) {
961 			IP6STAT_INC(ip6s_exthdrtoolong);
962 			*mp = NULL;
963 			return (-1);
964 		}
965 	}
966 	hbh = (struct ip6_hbh *)(mtod(m, caddr_t) + off);
967 	off += hbhlen;
968 	hbhlen -= sizeof(struct ip6_hbh);
969 	if (ip6_process_hopopts(m, (u_int8_t *)hbh + sizeof(struct ip6_hbh),
970 				hbhlen, rtalertp, plenp) < 0) {
971 		*mp = NULL;
972 		return (-1);
973 	}
974 
975 	*offp = off;
976 	*mp = m;
977 	return (0);
978 }
979 
980 /*
981  * Search header for all Hop-by-hop options and process each option.
982  * This function is separate from ip6_hopopts_input() in order to
983  * handle a case where the sending node itself process its hop-by-hop
984  * options header. In such a case, the function is called from ip6_output().
985  *
986  * The function assumes that hbh header is located right after the IPv6 header
987  * (RFC2460 p7), opthead is pointer into data content in m, and opthead to
988  * opthead + hbhlen is located in contiguous memory region.
989  */
990 int
991 ip6_process_hopopts(struct mbuf *m, u_int8_t *opthead, int hbhlen,
992     u_int32_t *rtalertp, u_int32_t *plenp)
993 {
994 	struct ip6_hdr *ip6;
995 	int optlen = 0;
996 	u_int8_t *opt = opthead;
997 	u_int16_t rtalert_val;
998 	u_int32_t jumboplen;
999 	const int erroff = sizeof(struct ip6_hdr) + sizeof(struct ip6_hbh);
1000 
1001 	for (; hbhlen > 0; hbhlen -= optlen, opt += optlen) {
1002 		switch (*opt) {
1003 		case IP6OPT_PAD1:
1004 			optlen = 1;
1005 			break;
1006 		case IP6OPT_PADN:
1007 			if (hbhlen < IP6OPT_MINLEN) {
1008 				IP6STAT_INC(ip6s_toosmall);
1009 				goto bad;
1010 			}
1011 			optlen = *(opt + 1) + 2;
1012 			break;
1013 		case IP6OPT_ROUTER_ALERT:
1014 			/* XXX may need check for alignment */
1015 			if (hbhlen < IP6OPT_RTALERT_LEN) {
1016 				IP6STAT_INC(ip6s_toosmall);
1017 				goto bad;
1018 			}
1019 			if (*(opt + 1) != IP6OPT_RTALERT_LEN - 2) {
1020 				/* XXX stat */
1021 				icmp6_error(m, ICMP6_PARAM_PROB,
1022 				    ICMP6_PARAMPROB_HEADER,
1023 				    erroff + opt + 1 - opthead);
1024 				return (-1);
1025 			}
1026 			optlen = IP6OPT_RTALERT_LEN;
1027 			bcopy((caddr_t)(opt + 2), (caddr_t)&rtalert_val, 2);
1028 			*rtalertp = ntohs(rtalert_val);
1029 			break;
1030 		case IP6OPT_JUMBO:
1031 			/* XXX may need check for alignment */
1032 			if (hbhlen < IP6OPT_JUMBO_LEN) {
1033 				IP6STAT_INC(ip6s_toosmall);
1034 				goto bad;
1035 			}
1036 			if (*(opt + 1) != IP6OPT_JUMBO_LEN - 2) {
1037 				/* XXX stat */
1038 				icmp6_error(m, ICMP6_PARAM_PROB,
1039 				    ICMP6_PARAMPROB_HEADER,
1040 				    erroff + opt + 1 - opthead);
1041 				return (-1);
1042 			}
1043 			optlen = IP6OPT_JUMBO_LEN;
1044 
1045 			/*
1046 			 * IPv6 packets that have non 0 payload length
1047 			 * must not contain a jumbo payload option.
1048 			 */
1049 			ip6 = mtod(m, struct ip6_hdr *);
1050 			if (ip6->ip6_plen) {
1051 				IP6STAT_INC(ip6s_badoptions);
1052 				icmp6_error(m, ICMP6_PARAM_PROB,
1053 				    ICMP6_PARAMPROB_HEADER,
1054 				    erroff + opt - opthead);
1055 				return (-1);
1056 			}
1057 
1058 			/*
1059 			 * We may see jumbolen in unaligned location, so
1060 			 * we'd need to perform bcopy().
1061 			 */
1062 			bcopy(opt + 2, &jumboplen, sizeof(jumboplen));
1063 			jumboplen = (u_int32_t)htonl(jumboplen);
1064 
1065 #if 1
1066 			/*
1067 			 * if there are multiple jumbo payload options,
1068 			 * *plenp will be non-zero and the packet will be
1069 			 * rejected.
1070 			 * the behavior may need some debate in ipngwg -
1071 			 * multiple options does not make sense, however,
1072 			 * there's no explicit mention in specification.
1073 			 */
1074 			if (*plenp != 0) {
1075 				IP6STAT_INC(ip6s_badoptions);
1076 				icmp6_error(m, ICMP6_PARAM_PROB,
1077 				    ICMP6_PARAMPROB_HEADER,
1078 				    erroff + opt + 2 - opthead);
1079 				return (-1);
1080 			}
1081 #endif
1082 
1083 			/*
1084 			 * jumbo payload length must be larger than 65535.
1085 			 */
1086 			if (jumboplen <= IPV6_MAXPACKET) {
1087 				IP6STAT_INC(ip6s_badoptions);
1088 				icmp6_error(m, ICMP6_PARAM_PROB,
1089 				    ICMP6_PARAMPROB_HEADER,
1090 				    erroff + opt + 2 - opthead);
1091 				return (-1);
1092 			}
1093 			*plenp = jumboplen;
1094 
1095 			break;
1096 		default:		/* unknown option */
1097 			if (hbhlen < IP6OPT_MINLEN) {
1098 				IP6STAT_INC(ip6s_toosmall);
1099 				goto bad;
1100 			}
1101 			optlen = ip6_unknown_opt(opt, m,
1102 			    erroff + opt - opthead);
1103 			if (optlen == -1)
1104 				return (-1);
1105 			optlen += 2;
1106 			break;
1107 		}
1108 	}
1109 
1110 	return (0);
1111 
1112   bad:
1113 	m_freem(m);
1114 	return (-1);
1115 }
1116 
1117 /*
1118  * Unknown option processing.
1119  * The third argument `off' is the offset from the IPv6 header to the option,
1120  * which is necessary if the IPv6 header the and option header and IPv6 header
1121  * is not contiguous in order to return an ICMPv6 error.
1122  */
1123 int
1124 ip6_unknown_opt(u_int8_t *optp, struct mbuf *m, int off)
1125 {
1126 	struct ip6_hdr *ip6;
1127 
1128 	switch (IP6OPT_TYPE(*optp)) {
1129 	case IP6OPT_TYPE_SKIP: /* ignore the option */
1130 		return ((int)*(optp + 1));
1131 	case IP6OPT_TYPE_DISCARD:	/* silently discard */
1132 		m_freem(m);
1133 		return (-1);
1134 	case IP6OPT_TYPE_FORCEICMP: /* send ICMP even if multicasted */
1135 		IP6STAT_INC(ip6s_badoptions);
1136 		icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_OPTION, off);
1137 		return (-1);
1138 	case IP6OPT_TYPE_ICMP: /* send ICMP if not multicasted */
1139 		IP6STAT_INC(ip6s_badoptions);
1140 		ip6 = mtod(m, struct ip6_hdr *);
1141 		if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) ||
1142 		    (m->m_flags & (M_BCAST|M_MCAST)))
1143 			m_freem(m);
1144 		else
1145 			icmp6_error(m, ICMP6_PARAM_PROB,
1146 				    ICMP6_PARAMPROB_OPTION, off);
1147 		return (-1);
1148 	}
1149 
1150 	m_freem(m);		/* XXX: NOTREACHED */
1151 	return (-1);
1152 }
1153 
1154 /*
1155  * Create the "control" list for this pcb.
1156  * These functions will not modify mbuf chain at all.
1157  *
1158  * The routine will be called from upper layer handlers like tcp6_input().
1159  * Thus the routine assumes that the caller (tcp6_input) have already
1160  * called m_pullup() and all the extension headers are located in the
1161  * very first mbuf on the mbuf chain.
1162  *
1163  * ip6_savecontrol_v4 will handle those options that are possible to be
1164  * set on a v4-mapped socket.
1165  * ip6_savecontrol will directly call ip6_savecontrol_v4 to handle those
1166  * options and handle the v6-only ones itself.
1167  */
1168 struct mbuf **
1169 ip6_savecontrol_v4(struct inpcb *inp, struct mbuf *m, struct mbuf **mp,
1170     int *v4only)
1171 {
1172 	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
1173 
1174 #ifdef SO_TIMESTAMP
1175 	if ((inp->inp_socket->so_options & SO_TIMESTAMP) != 0) {
1176 		union {
1177 			struct timeval tv;
1178 			struct bintime bt;
1179 			struct timespec ts;
1180 		} t;
1181 		struct bintime boottimebin, bt1;
1182 		struct timespec ts1;
1183 		bool stamped;
1184 
1185 		stamped = false;
1186 		switch (inp->inp_socket->so_ts_clock) {
1187 		case SO_TS_REALTIME_MICRO:
1188 			if ((m->m_flags & (M_PKTHDR | M_TSTMP)) == (M_PKTHDR |
1189 			    M_TSTMP)) {
1190 				mbuf_tstmp2timespec(m, &ts1);
1191 				timespec2bintime(&ts1, &bt1);
1192 				getboottimebin(&boottimebin);
1193 				bintime_add(&bt1, &boottimebin);
1194 				bintime2timeval(&bt1, &t.tv);
1195 			} else {
1196 				microtime(&t.tv);
1197 			}
1198 			*mp = sbcreatecontrol(&t.tv, sizeof(t.tv),
1199 			    SCM_TIMESTAMP, SOL_SOCKET, M_NOWAIT);
1200 			if (*mp != NULL) {
1201 				mp = &(*mp)->m_next;
1202 				stamped = true;
1203 			}
1204 			break;
1205 
1206 		case SO_TS_BINTIME:
1207 			if ((m->m_flags & (M_PKTHDR | M_TSTMP)) == (M_PKTHDR |
1208 			    M_TSTMP)) {
1209 				mbuf_tstmp2timespec(m, &ts1);
1210 				timespec2bintime(&ts1, &t.bt);
1211 				getboottimebin(&boottimebin);
1212 				bintime_add(&t.bt, &boottimebin);
1213 			} else {
1214 				bintime(&t.bt);
1215 			}
1216 			*mp = sbcreatecontrol(&t.bt, sizeof(t.bt), SCM_BINTIME,
1217 			    SOL_SOCKET, M_NOWAIT);
1218 			if (*mp != NULL) {
1219 				mp = &(*mp)->m_next;
1220 				stamped = true;
1221 			}
1222 			break;
1223 
1224 		case SO_TS_REALTIME:
1225 			if ((m->m_flags & (M_PKTHDR | M_TSTMP)) == (M_PKTHDR |
1226 			    M_TSTMP)) {
1227 				mbuf_tstmp2timespec(m, &t.ts);
1228 				getboottimebin(&boottimebin);
1229 				bintime2timespec(&boottimebin, &ts1);
1230 				timespecadd(&t.ts, &ts1, &t.ts);
1231 			} else {
1232 				nanotime(&t.ts);
1233 			}
1234 			*mp = sbcreatecontrol(&t.ts, sizeof(t.ts),
1235 			    SCM_REALTIME, SOL_SOCKET, M_NOWAIT);
1236 			if (*mp != NULL) {
1237 				mp = &(*mp)->m_next;
1238 				stamped = true;
1239 			}
1240 			break;
1241 
1242 		case SO_TS_MONOTONIC:
1243 			if ((m->m_flags & (M_PKTHDR | M_TSTMP)) == (M_PKTHDR |
1244 			    M_TSTMP))
1245 				mbuf_tstmp2timespec(m, &t.ts);
1246 			else
1247 				nanouptime(&t.ts);
1248 			*mp = sbcreatecontrol(&t.ts, sizeof(t.ts),
1249 			    SCM_MONOTONIC, SOL_SOCKET, M_NOWAIT);
1250 			if (*mp != NULL) {
1251 				mp = &(*mp)->m_next;
1252 				stamped = true;
1253 			}
1254 			break;
1255 
1256 		default:
1257 			panic("unknown (corrupted) so_ts_clock");
1258 		}
1259 		if (stamped && (m->m_flags & (M_PKTHDR | M_TSTMP)) ==
1260 		    (M_PKTHDR | M_TSTMP)) {
1261 			struct sock_timestamp_info sti;
1262 
1263 			bzero(&sti, sizeof(sti));
1264 			sti.st_info_flags = ST_INFO_HW;
1265 			if ((m->m_flags & M_TSTMP_HPREC) != 0)
1266 				sti.st_info_flags |= ST_INFO_HW_HPREC;
1267 			*mp = sbcreatecontrol(&sti, sizeof(sti), SCM_TIME_INFO,
1268 			    SOL_SOCKET, M_NOWAIT);
1269 			if (*mp != NULL)
1270 				mp = &(*mp)->m_next;
1271 		}
1272 	}
1273 #endif
1274 
1275 #define IS2292(inp, x, y)	(((inp)->inp_flags & IN6P_RFC2292) ? (x) : (y))
1276 	/* RFC 2292 sec. 5 */
1277 	if ((inp->inp_flags & IN6P_PKTINFO) != 0) {
1278 		struct in6_pktinfo pi6;
1279 
1280 		if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) {
1281 #ifdef INET
1282 			struct ip *ip;
1283 
1284 			ip = mtod(m, struct ip *);
1285 			pi6.ipi6_addr.s6_addr32[0] = 0;
1286 			pi6.ipi6_addr.s6_addr32[1] = 0;
1287 			pi6.ipi6_addr.s6_addr32[2] = IPV6_ADDR_INT32_SMP;
1288 			pi6.ipi6_addr.s6_addr32[3] = ip->ip_dst.s_addr;
1289 #else
1290 			/* We won't hit this code */
1291 			bzero(&pi6.ipi6_addr, sizeof(struct in6_addr));
1292 #endif
1293 		} else {
1294 			bcopy(&ip6->ip6_dst, &pi6.ipi6_addr, sizeof(struct in6_addr));
1295 			in6_clearscope(&pi6.ipi6_addr);	/* XXX */
1296 		}
1297 		pi6.ipi6_ifindex =
1298 		    (m && m->m_pkthdr.rcvif) ? m->m_pkthdr.rcvif->if_index : 0;
1299 
1300 		*mp = sbcreatecontrol(&pi6, sizeof(struct in6_pktinfo),
1301 		    IS2292(inp, IPV6_2292PKTINFO, IPV6_PKTINFO), IPPROTO_IPV6,
1302 		    M_NOWAIT);
1303 		if (*mp)
1304 			mp = &(*mp)->m_next;
1305 	}
1306 
1307 	if ((inp->inp_flags & IN6P_HOPLIMIT) != 0) {
1308 		int hlim;
1309 
1310 		if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) {
1311 #ifdef INET
1312 			struct ip *ip;
1313 
1314 			ip = mtod(m, struct ip *);
1315 			hlim = ip->ip_ttl;
1316 #else
1317 			/* We won't hit this code */
1318 			hlim = 0;
1319 #endif
1320 		} else {
1321 			hlim = ip6->ip6_hlim & 0xff;
1322 		}
1323 		*mp = sbcreatecontrol(&hlim, sizeof(int),
1324 		    IS2292(inp, IPV6_2292HOPLIMIT, IPV6_HOPLIMIT),
1325 		    IPPROTO_IPV6, M_NOWAIT);
1326 		if (*mp)
1327 			mp = &(*mp)->m_next;
1328 	}
1329 
1330 	if ((inp->inp_flags & IN6P_TCLASS) != 0) {
1331 		int tclass;
1332 
1333 		if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) {
1334 #ifdef INET
1335 			struct ip *ip;
1336 
1337 			ip = mtod(m, struct ip *);
1338 			tclass = ip->ip_tos;
1339 #else
1340 			/* We won't hit this code */
1341 			tclass = 0;
1342 #endif
1343 		} else {
1344 			u_int32_t flowinfo;
1345 
1346 			flowinfo = (u_int32_t)ntohl(ip6->ip6_flow & IPV6_FLOWINFO_MASK);
1347 			flowinfo >>= 20;
1348 			tclass = flowinfo & 0xff;
1349 		}
1350 		*mp = sbcreatecontrol(&tclass, sizeof(int), IPV6_TCLASS,
1351 		    IPPROTO_IPV6, M_NOWAIT);
1352 		if (*mp)
1353 			mp = &(*mp)->m_next;
1354 	}
1355 
1356 	if (v4only != NULL) {
1357 		if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) {
1358 			*v4only = 1;
1359 		} else {
1360 			*v4only = 0;
1361 		}
1362 	}
1363 
1364 	return (mp);
1365 }
1366 
1367 void
1368 ip6_savecontrol(struct inpcb *inp, struct mbuf *m, struct mbuf **mp)
1369 {
1370 	struct ip6_hdr *ip6;
1371 	int v4only = 0;
1372 
1373 	mp = ip6_savecontrol_v4(inp, m, mp, &v4only);
1374 	if (v4only)
1375 		return;
1376 
1377 	ip6 = mtod(m, struct ip6_hdr *);
1378 	/*
1379 	 * IPV6_HOPOPTS socket option.  Recall that we required super-user
1380 	 * privilege for the option (see ip6_ctloutput), but it might be too
1381 	 * strict, since there might be some hop-by-hop options which can be
1382 	 * returned to normal user.
1383 	 * See also RFC 2292 section 6 (or RFC 3542 section 8).
1384 	 */
1385 	if ((inp->inp_flags & IN6P_HOPOPTS) != 0) {
1386 		/*
1387 		 * Check if a hop-by-hop options header is contatined in the
1388 		 * received packet, and if so, store the options as ancillary
1389 		 * data. Note that a hop-by-hop options header must be
1390 		 * just after the IPv6 header, which is assured through the
1391 		 * IPv6 input processing.
1392 		 */
1393 		if (ip6->ip6_nxt == IPPROTO_HOPOPTS) {
1394 			struct ip6_hbh *hbh;
1395 			u_int hbhlen;
1396 
1397 			hbh = (struct ip6_hbh *)(ip6 + 1);
1398 			hbhlen = (hbh->ip6h_len + 1) << 3;
1399 
1400 			/*
1401 			 * XXX: We copy the whole header even if a
1402 			 * jumbo payload option is included, the option which
1403 			 * is to be removed before returning according to
1404 			 * RFC2292.
1405 			 * Note: this constraint is removed in RFC3542
1406 			 */
1407 			*mp = sbcreatecontrol(hbh, hbhlen,
1408 			    IS2292(inp, IPV6_2292HOPOPTS, IPV6_HOPOPTS),
1409 			    IPPROTO_IPV6, M_NOWAIT);
1410 			if (*mp)
1411 				mp = &(*mp)->m_next;
1412 		}
1413 	}
1414 
1415 	if ((inp->inp_flags & (IN6P_RTHDR | IN6P_DSTOPTS)) != 0) {
1416 		int nxt = ip6->ip6_nxt, off = sizeof(struct ip6_hdr);
1417 
1418 		/*
1419 		 * Search for destination options headers or routing
1420 		 * header(s) through the header chain, and stores each
1421 		 * header as ancillary data.
1422 		 * Note that the order of the headers remains in
1423 		 * the chain of ancillary data.
1424 		 */
1425 		while (1) {	/* is explicit loop prevention necessary? */
1426 			struct ip6_ext *ip6e = NULL;
1427 			u_int elen;
1428 
1429 			/*
1430 			 * if it is not an extension header, don't try to
1431 			 * pull it from the chain.
1432 			 */
1433 			switch (nxt) {
1434 			case IPPROTO_DSTOPTS:
1435 			case IPPROTO_ROUTING:
1436 			case IPPROTO_HOPOPTS:
1437 			case IPPROTO_AH: /* is it possible? */
1438 				break;
1439 			default:
1440 				goto loopend;
1441 			}
1442 
1443 			if (off + sizeof(*ip6e) > m->m_len)
1444 				goto loopend;
1445 			ip6e = (struct ip6_ext *)(mtod(m, caddr_t) + off);
1446 			if (nxt == IPPROTO_AH)
1447 				elen = (ip6e->ip6e_len + 2) << 2;
1448 			else
1449 				elen = (ip6e->ip6e_len + 1) << 3;
1450 			if (off + elen > m->m_len)
1451 				goto loopend;
1452 
1453 			switch (nxt) {
1454 			case IPPROTO_DSTOPTS:
1455 				if (!(inp->inp_flags & IN6P_DSTOPTS))
1456 					break;
1457 
1458 				*mp = sbcreatecontrol(ip6e, elen,
1459 				    IS2292(inp, IPV6_2292DSTOPTS, IPV6_DSTOPTS),
1460 				    IPPROTO_IPV6, M_NOWAIT);
1461 				if (*mp)
1462 					mp = &(*mp)->m_next;
1463 				break;
1464 			case IPPROTO_ROUTING:
1465 				if (!(inp->inp_flags & IN6P_RTHDR))
1466 					break;
1467 
1468 				*mp = sbcreatecontrol(ip6e, elen,
1469 				    IS2292(inp, IPV6_2292RTHDR, IPV6_RTHDR),
1470 				    IPPROTO_IPV6, M_NOWAIT);
1471 				if (*mp)
1472 					mp = &(*mp)->m_next;
1473 				break;
1474 			case IPPROTO_HOPOPTS:
1475 			case IPPROTO_AH: /* is it possible? */
1476 				break;
1477 
1478 			default:
1479 				/*
1480 				 * other cases have been filtered in the above.
1481 				 * none will visit this case.  here we supply
1482 				 * the code just in case (nxt overwritten or
1483 				 * other cases).
1484 				 */
1485 				goto loopend;
1486 			}
1487 
1488 			/* proceed with the next header. */
1489 			off += elen;
1490 			nxt = ip6e->ip6e_nxt;
1491 			ip6e = NULL;
1492 		}
1493 	  loopend:
1494 		;
1495 	}
1496 
1497 	if (inp->inp_flags2 & INP_RECVFLOWID) {
1498 		uint32_t flowid, flow_type;
1499 
1500 		flowid = m->m_pkthdr.flowid;
1501 		flow_type = M_HASHTYPE_GET(m);
1502 
1503 		/*
1504 		 * XXX should handle the failure of one or the
1505 		 * other - don't populate both?
1506 		 */
1507 		*mp = sbcreatecontrol(&flowid, sizeof(uint32_t), IPV6_FLOWID,
1508 		    IPPROTO_IPV6, M_NOWAIT);
1509 		if (*mp)
1510 			mp = &(*mp)->m_next;
1511 		*mp = sbcreatecontrol(&flow_type, sizeof(uint32_t),
1512 		    IPV6_FLOWTYPE, IPPROTO_IPV6, M_NOWAIT);
1513 		if (*mp)
1514 			mp = &(*mp)->m_next;
1515 	}
1516 
1517 #ifdef	RSS
1518 	if (inp->inp_flags2 & INP_RECVRSSBUCKETID) {
1519 		uint32_t flowid, flow_type;
1520 		uint32_t rss_bucketid;
1521 
1522 		flowid = m->m_pkthdr.flowid;
1523 		flow_type = M_HASHTYPE_GET(m);
1524 
1525 		if (rss_hash2bucket(flowid, flow_type, &rss_bucketid) == 0) {
1526 			*mp = sbcreatecontrol(&rss_bucketid, sizeof(uint32_t),
1527 			    IPV6_RSSBUCKETID, IPPROTO_IPV6, M_NOWAIT);
1528 			if (*mp)
1529 				mp = &(*mp)->m_next;
1530 		}
1531 	}
1532 #endif
1533 
1534 }
1535 #undef IS2292
1536 
1537 void
1538 ip6_notify_pmtu(struct inpcb *inp, struct sockaddr_in6 *dst, u_int32_t mtu)
1539 {
1540 	struct socket *so;
1541 	struct mbuf *m_mtu;
1542 	struct ip6_mtuinfo mtuctl;
1543 
1544 	KASSERT(inp != NULL, ("%s: inp == NULL", __func__));
1545 	/*
1546 	 * Notify the error by sending IPV6_PATHMTU ancillary data if
1547 	 * application wanted to know the MTU value.
1548 	 * NOTE: we notify disconnected sockets, because some udp
1549 	 * applications keep sending sockets disconnected.
1550 	 * NOTE: our implementation doesn't notify connected sockets that has
1551 	 * foreign address that is different than given destination addresses
1552 	 * (this is permitted by RFC 3542).
1553 	 */
1554 	if ((inp->inp_flags & IN6P_MTU) == 0 || (
1555 	    !IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr) &&
1556 	    !IN6_ARE_ADDR_EQUAL(&inp->in6p_faddr, &dst->sin6_addr)))
1557 		return;
1558 
1559 	mtuctl.ip6m_mtu = mtu;
1560 	mtuctl.ip6m_addr = *dst;
1561 	if (sa6_recoverscope(&mtuctl.ip6m_addr))
1562 		return;
1563 
1564 	if ((m_mtu = sbcreatecontrol(&mtuctl, sizeof(mtuctl), IPV6_PATHMTU,
1565 	    IPPROTO_IPV6, M_NOWAIT)) == NULL)
1566 		return;
1567 
1568 	so =  inp->inp_socket;
1569 	if (sbappendaddr(&so->so_rcv, (struct sockaddr *)dst, NULL, m_mtu)
1570 	    == 0) {
1571 		soroverflow(so);
1572 		m_freem(m_mtu);
1573 		/* XXX: should count statistics */
1574 	} else
1575 		sorwakeup(so);
1576 }
1577 
1578 /*
1579  * Get pointer to the previous header followed by the header
1580  * currently processed.
1581  */
1582 int
1583 ip6_get_prevhdr(const struct mbuf *m, int off)
1584 {
1585 	struct ip6_ext ip6e;
1586 	struct ip6_hdr *ip6;
1587 	int len, nlen, nxt;
1588 
1589 	if (off == sizeof(struct ip6_hdr))
1590 		return (offsetof(struct ip6_hdr, ip6_nxt));
1591 	if (off < sizeof(struct ip6_hdr))
1592 		panic("%s: off < sizeof(struct ip6_hdr)", __func__);
1593 
1594 	ip6 = mtod(m, struct ip6_hdr *);
1595 	nxt = ip6->ip6_nxt;
1596 	len = sizeof(struct ip6_hdr);
1597 	nlen = 0;
1598 	while (len < off) {
1599 		m_copydata(m, len, sizeof(ip6e), (caddr_t)&ip6e);
1600 		switch (nxt) {
1601 		case IPPROTO_FRAGMENT:
1602 			nlen = sizeof(struct ip6_frag);
1603 			break;
1604 		case IPPROTO_AH:
1605 			nlen = (ip6e.ip6e_len + 2) << 2;
1606 			break;
1607 		default:
1608 			nlen = (ip6e.ip6e_len + 1) << 3;
1609 		}
1610 		len += nlen;
1611 		nxt = ip6e.ip6e_nxt;
1612 	}
1613 	return (len - nlen);
1614 }
1615 
1616 /*
1617  * get next header offset.  m will be retained.
1618  */
1619 int
1620 ip6_nexthdr(const struct mbuf *m, int off, int proto, int *nxtp)
1621 {
1622 	struct ip6_hdr ip6;
1623 	struct ip6_ext ip6e;
1624 	struct ip6_frag fh;
1625 
1626 	/* just in case */
1627 	if (m == NULL)
1628 		panic("ip6_nexthdr: m == NULL");
1629 	if ((m->m_flags & M_PKTHDR) == 0 || m->m_pkthdr.len < off)
1630 		return -1;
1631 
1632 	switch (proto) {
1633 	case IPPROTO_IPV6:
1634 		if (m->m_pkthdr.len < off + sizeof(ip6))
1635 			return -1;
1636 		m_copydata(m, off, sizeof(ip6), (caddr_t)&ip6);
1637 		if (nxtp)
1638 			*nxtp = ip6.ip6_nxt;
1639 		off += sizeof(ip6);
1640 		return off;
1641 
1642 	case IPPROTO_FRAGMENT:
1643 		/*
1644 		 * terminate parsing if it is not the first fragment,
1645 		 * it does not make sense to parse through it.
1646 		 */
1647 		if (m->m_pkthdr.len < off + sizeof(fh))
1648 			return -1;
1649 		m_copydata(m, off, sizeof(fh), (caddr_t)&fh);
1650 		/* IP6F_OFF_MASK = 0xfff8(BigEndian), 0xf8ff(LittleEndian) */
1651 		if (fh.ip6f_offlg & IP6F_OFF_MASK)
1652 			return -1;
1653 		if (nxtp)
1654 			*nxtp = fh.ip6f_nxt;
1655 		off += sizeof(struct ip6_frag);
1656 		return off;
1657 
1658 	case IPPROTO_AH:
1659 		if (m->m_pkthdr.len < off + sizeof(ip6e))
1660 			return -1;
1661 		m_copydata(m, off, sizeof(ip6e), (caddr_t)&ip6e);
1662 		if (nxtp)
1663 			*nxtp = ip6e.ip6e_nxt;
1664 		off += (ip6e.ip6e_len + 2) << 2;
1665 		return off;
1666 
1667 	case IPPROTO_HOPOPTS:
1668 	case IPPROTO_ROUTING:
1669 	case IPPROTO_DSTOPTS:
1670 		if (m->m_pkthdr.len < off + sizeof(ip6e))
1671 			return -1;
1672 		m_copydata(m, off, sizeof(ip6e), (caddr_t)&ip6e);
1673 		if (nxtp)
1674 			*nxtp = ip6e.ip6e_nxt;
1675 		off += (ip6e.ip6e_len + 1) << 3;
1676 		return off;
1677 
1678 	case IPPROTO_NONE:
1679 	case IPPROTO_ESP:
1680 	case IPPROTO_IPCOMP:
1681 		/* give up */
1682 		return -1;
1683 
1684 	default:
1685 		return -1;
1686 	}
1687 
1688 	/* NOTREACHED */
1689 }
1690 
1691 /*
1692  * get offset for the last header in the chain.  m will be kept untainted.
1693  */
1694 int
1695 ip6_lasthdr(const struct mbuf *m, int off, int proto, int *nxtp)
1696 {
1697 	int newoff;
1698 	int nxt;
1699 
1700 	if (!nxtp) {
1701 		nxt = -1;
1702 		nxtp = &nxt;
1703 	}
1704 	while (1) {
1705 		newoff = ip6_nexthdr(m, off, proto, nxtp);
1706 		if (newoff < 0)
1707 			return off;
1708 		else if (newoff < off)
1709 			return -1;	/* invalid */
1710 		else if (newoff == off)
1711 			return newoff;
1712 
1713 		off = newoff;
1714 		proto = *nxtp;
1715 	}
1716 }
1717 
1718 /*
1719  * System control for IP6
1720  */
1721 
1722 u_char	inet6ctlerrmap[PRC_NCMDS] = {
1723 	0,		0,		0,		0,
1724 	0,		EMSGSIZE,	EHOSTDOWN,	EHOSTUNREACH,
1725 	EHOSTUNREACH,	EHOSTUNREACH,	ECONNREFUSED,	ECONNREFUSED,
1726 	EMSGSIZE,	EHOSTUNREACH,	0,		0,
1727 	0,		0,		EHOSTUNREACH,	0,
1728 	ENOPROTOOPT,	ECONNREFUSED
1729 };
1730