xref: /freebsd/sys/netinet6/ip6_input.c (revision 848ee2a3a8b47c9905fc51fefcf60eb371edbb98)
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 
74 #include <sys/param.h>
75 #include <sys/systm.h>
76 #include <sys/hhook.h>
77 #include <sys/malloc.h>
78 #include <sys/mbuf.h>
79 #include <sys/proc.h>
80 #include <sys/domain.h>
81 #include <sys/protosw.h>
82 #include <sys/sdt.h>
83 #include <sys/socket.h>
84 #include <sys/socketvar.h>
85 #include <sys/errno.h>
86 #include <sys/time.h>
87 #include <sys/kernel.h>
88 #include <sys/lock.h>
89 #include <sys/rmlock.h>
90 #include <sys/syslog.h>
91 #include <sys/sysctl.h>
92 
93 #include <net/if.h>
94 #include <net/if_var.h>
95 #include <net/if_types.h>
96 #include <net/if_dl.h>
97 #include <net/route.h>
98 #include <net/netisr.h>
99 #include <net/rss_config.h>
100 #include <net/pfil.h>
101 #include <net/vnet.h>
102 
103 #include <netinet/in.h>
104 #include <netinet/in_kdtrace.h>
105 #include <netinet/ip_var.h>
106 #include <netinet/in_systm.h>
107 #include <net/if_llatbl.h>
108 #ifdef INET
109 #include <netinet/ip.h>
110 #include <netinet/ip_icmp.h>
111 #endif /* INET */
112 #include <netinet/ip6.h>
113 #include <netinet6/in6_var.h>
114 #include <netinet6/ip6_var.h>
115 #include <netinet/in_pcb.h>
116 #include <netinet/icmp6.h>
117 #include <netinet6/scope6_var.h>
118 #include <netinet6/in6_ifattach.h>
119 #include <netinet6/mld6_var.h>
120 #include <netinet6/nd6.h>
121 #include <netinet6/in6_rss.h>
122 
123 #include <netipsec/ipsec_support.h>
124 
125 #include <netinet6/ip6protosw.h>
126 
127 extern struct domain inet6domain;
128 
129 u_char ip6_protox[IPPROTO_MAX];
130 VNET_DEFINE(struct in6_ifaddrhead, in6_ifaddrhead);
131 VNET_DEFINE(struct in6_ifaddrlisthead *, in6_ifaddrhashtbl);
132 VNET_DEFINE(u_long, in6_ifaddrhmask);
133 
134 static struct netisr_handler ip6_nh = {
135 	.nh_name = "ip6",
136 	.nh_handler = ip6_input,
137 	.nh_proto = NETISR_IPV6,
138 #ifdef RSS
139 	.nh_m2cpuid = rss_soft_m2cpuid_v6,
140 	.nh_policy = NETISR_POLICY_CPU,
141 	.nh_dispatch = NETISR_DISPATCH_HYBRID,
142 #else
143 	.nh_policy = NETISR_POLICY_FLOW,
144 #endif
145 };
146 
147 static int
148 sysctl_netinet6_intr_queue_maxlen(SYSCTL_HANDLER_ARGS)
149 {
150 	int error, qlimit;
151 
152 	netisr_getqlimit(&ip6_nh, &qlimit);
153 	error = sysctl_handle_int(oidp, &qlimit, 0, req);
154 	if (error || !req->newptr)
155 		return (error);
156 	if (qlimit < 1)
157 		return (EINVAL);
158 	return (netisr_setqlimit(&ip6_nh, qlimit));
159 }
160 SYSCTL_DECL(_net_inet6_ip6);
161 SYSCTL_PROC(_net_inet6_ip6, IPV6CTL_INTRQMAXLEN, intr_queue_maxlen,
162     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
163     0, 0, sysctl_netinet6_intr_queue_maxlen, "I",
164     "Maximum size of the IPv6 input queue");
165 
166 VNET_DEFINE_STATIC(bool, ip6_sav) = true;
167 #define	V_ip6_sav	VNET(ip6_sav)
168 SYSCTL_BOOL(_net_inet6_ip6, OID_AUTO, source_address_validation,
169     CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ip6_sav), true,
170     "Drop incoming packets with source address that is a local address");
171 
172 #ifdef RSS
173 static struct netisr_handler ip6_direct_nh = {
174 	.nh_name = "ip6_direct",
175 	.nh_handler = ip6_direct_input,
176 	.nh_proto = NETISR_IPV6_DIRECT,
177 	.nh_m2cpuid = rss_soft_m2cpuid_v6,
178 	.nh_policy = NETISR_POLICY_CPU,
179 	.nh_dispatch = NETISR_DISPATCH_HYBRID,
180 };
181 
182 static int
183 sysctl_netinet6_intr_direct_queue_maxlen(SYSCTL_HANDLER_ARGS)
184 {
185 	int error, qlimit;
186 
187 	netisr_getqlimit(&ip6_direct_nh, &qlimit);
188 	error = sysctl_handle_int(oidp, &qlimit, 0, req);
189 	if (error || !req->newptr)
190 		return (error);
191 	if (qlimit < 1)
192 		return (EINVAL);
193 	return (netisr_setqlimit(&ip6_direct_nh, qlimit));
194 }
195 SYSCTL_PROC(_net_inet6_ip6, IPV6CTL_INTRDQMAXLEN, intr_direct_queue_maxlen,
196     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
197     0, 0, sysctl_netinet6_intr_direct_queue_maxlen, "I",
198     "Maximum size of the IPv6 direct input queue");
199 
200 #endif
201 
202 VNET_DEFINE(pfil_head_t, inet6_pfil_head);
203 
204 VNET_PCPUSTAT_DEFINE(struct ip6stat, ip6stat);
205 VNET_PCPUSTAT_SYSINIT(ip6stat);
206 #ifdef VIMAGE
207 VNET_PCPUSTAT_SYSUNINIT(ip6stat);
208 #endif /* VIMAGE */
209 
210 struct rmlock in6_ifaddr_lock;
211 RM_SYSINIT(in6_ifaddr_lock, &in6_ifaddr_lock, "in6_ifaddr_lock");
212 
213 static int ip6_hopopts_input(u_int32_t *, u_int32_t *, struct mbuf **, int *);
214 
215 /*
216  * IP6 initialization: fill in IP6 protocol switch table.
217  * All protocols not implemented in kernel go to raw IP6 protocol handler.
218  */
219 void
220 ip6_init(void)
221 {
222 	struct pfil_head_args args;
223 	struct protosw *pr;
224 	int i;
225 
226 	TUNABLE_INT_FETCH("net.inet6.ip6.auto_linklocal",
227 	    &V_ip6_auto_linklocal);
228 	TUNABLE_INT_FETCH("net.inet6.ip6.accept_rtadv", &V_ip6_accept_rtadv);
229 	TUNABLE_INT_FETCH("net.inet6.ip6.no_radr", &V_ip6_no_radr);
230 
231 	CK_STAILQ_INIT(&V_in6_ifaddrhead);
232 	V_in6_ifaddrhashtbl = hashinit(IN6ADDR_NHASH, M_IFADDR,
233 	    &V_in6_ifaddrhmask);
234 
235 	/* Initialize packet filter hooks. */
236 	args.pa_version = PFIL_VERSION;
237 	args.pa_flags = PFIL_IN | PFIL_OUT;
238 	args.pa_type = PFIL_TYPE_IP6;
239 	args.pa_headname = PFIL_INET6_NAME;
240 	V_inet6_pfil_head = pfil_head_register(&args);
241 
242 	if (hhook_head_register(HHOOK_TYPE_IPSEC_IN, AF_INET6,
243 	    &V_ipsec_hhh_in[HHOOK_IPSEC_INET6],
244 	    HHOOK_WAITOK | HHOOK_HEADISINVNET) != 0)
245 		printf("%s: WARNING: unable to register input helper hook\n",
246 		    __func__);
247 	if (hhook_head_register(HHOOK_TYPE_IPSEC_OUT, AF_INET6,
248 	    &V_ipsec_hhh_out[HHOOK_IPSEC_INET6],
249 	    HHOOK_WAITOK | HHOOK_HEADISINVNET) != 0)
250 		printf("%s: WARNING: unable to register output helper hook\n",
251 		    __func__);
252 
253 	scope6_init();
254 	addrsel_policy_init();
255 	nd6_init();
256 	frag6_init();
257 
258 	V_ip6_desync_factor = arc4random() % MAX_TEMP_DESYNC_FACTOR;
259 
260 	/* Skip global initialization stuff for non-default instances. */
261 #ifdef VIMAGE
262 	if (!IS_DEFAULT_VNET(curvnet)) {
263 		netisr_register_vnet(&ip6_nh);
264 #ifdef RSS
265 		netisr_register_vnet(&ip6_direct_nh);
266 #endif
267 		return;
268 	}
269 #endif
270 
271 	pr = pffindproto(PF_INET6, IPPROTO_RAW, SOCK_RAW);
272 	if (pr == NULL)
273 		panic("ip6_init");
274 
275 	/* Initialize the entire ip6_protox[] array to IPPROTO_RAW. */
276 	for (i = 0; i < IPPROTO_MAX; i++)
277 		ip6_protox[i] = pr - inet6sw;
278 	/*
279 	 * Cycle through IP protocols and put them into the appropriate place
280 	 * in ip6_protox[].
281 	 */
282 	for (pr = inet6domain.dom_protosw;
283 	    pr < inet6domain.dom_protoswNPROTOSW; pr++)
284 		if (pr->pr_domain->dom_family == PF_INET6 &&
285 		    pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) {
286 			/* Be careful to only index valid IP protocols. */
287 			if (pr->pr_protocol < IPPROTO_MAX)
288 				ip6_protox[pr->pr_protocol] = pr - inet6sw;
289 		}
290 
291 	netisr_register(&ip6_nh);
292 #ifdef RSS
293 	netisr_register(&ip6_direct_nh);
294 #endif
295 }
296 
297 /*
298  * The protocol to be inserted into ip6_protox[] must be already registered
299  * in inet6sw[], either statically or through pf_proto_register().
300  */
301 int
302 ip6proto_register(short ip6proto)
303 {
304 	struct protosw *pr;
305 
306 	/* Sanity checks. */
307 	if (ip6proto <= 0 || ip6proto >= IPPROTO_MAX)
308 		return (EPROTONOSUPPORT);
309 
310 	/*
311 	 * The protocol slot must not be occupied by another protocol
312 	 * already.  An index pointing to IPPROTO_RAW is unused.
313 	 */
314 	pr = pffindproto(PF_INET6, IPPROTO_RAW, SOCK_RAW);
315 	if (pr == NULL)
316 		return (EPFNOSUPPORT);
317 	if (ip6_protox[ip6proto] != pr - inet6sw)	/* IPPROTO_RAW */
318 		return (EEXIST);
319 
320 	/*
321 	 * Find the protocol position in inet6sw[] and set the index.
322 	 */
323 	for (pr = inet6domain.dom_protosw;
324 	    pr < inet6domain.dom_protoswNPROTOSW; pr++) {
325 		if (pr->pr_domain->dom_family == PF_INET6 &&
326 		    pr->pr_protocol && pr->pr_protocol == ip6proto) {
327 			ip6_protox[pr->pr_protocol] = pr - inet6sw;
328 			return (0);
329 		}
330 	}
331 	return (EPROTONOSUPPORT);
332 }
333 
334 int
335 ip6proto_unregister(short ip6proto)
336 {
337 	struct protosw *pr;
338 
339 	/* Sanity checks. */
340 	if (ip6proto <= 0 || ip6proto >= IPPROTO_MAX)
341 		return (EPROTONOSUPPORT);
342 
343 	/* Check if the protocol was indeed registered. */
344 	pr = pffindproto(PF_INET6, IPPROTO_RAW, SOCK_RAW);
345 	if (pr == NULL)
346 		return (EPFNOSUPPORT);
347 	if (ip6_protox[ip6proto] == pr - inet6sw)	/* IPPROTO_RAW */
348 		return (ENOENT);
349 
350 	/* Reset the protocol slot to IPPROTO_RAW. */
351 	ip6_protox[ip6proto] = pr - inet6sw;
352 	return (0);
353 }
354 
355 #ifdef VIMAGE
356 static void
357 ip6_destroy(void *unused __unused)
358 {
359 	struct ifaddr *ifa, *nifa;
360 	struct ifnet *ifp;
361 	int error;
362 
363 #ifdef RSS
364 	netisr_unregister_vnet(&ip6_direct_nh);
365 #endif
366 	netisr_unregister_vnet(&ip6_nh);
367 
368 	pfil_head_unregister(V_inet6_pfil_head);
369 	error = hhook_head_deregister(V_ipsec_hhh_in[HHOOK_IPSEC_INET6]);
370 	if (error != 0) {
371 		printf("%s: WARNING: unable to deregister input helper hook "
372 		    "type HHOOK_TYPE_IPSEC_IN, id HHOOK_IPSEC_INET6: "
373 		    "error %d returned\n", __func__, error);
374 	}
375 	error = hhook_head_deregister(V_ipsec_hhh_out[HHOOK_IPSEC_INET6]);
376 	if (error != 0) {
377 		printf("%s: WARNING: unable to deregister output helper hook "
378 		    "type HHOOK_TYPE_IPSEC_OUT, id HHOOK_IPSEC_INET6: "
379 		    "error %d returned\n", __func__, error);
380 	}
381 
382 	/* Cleanup addresses. */
383 	IFNET_RLOCK();
384 	CK_STAILQ_FOREACH(ifp, &V_ifnet, if_link) {
385 		/* Cannot lock here - lock recursion. */
386 		/* IF_ADDR_LOCK(ifp); */
387 		CK_STAILQ_FOREACH_SAFE(ifa, &ifp->if_addrhead, ifa_link, nifa) {
388 			if (ifa->ifa_addr->sa_family != AF_INET6)
389 				continue;
390 			in6_purgeaddr(ifa);
391 		}
392 		/* IF_ADDR_UNLOCK(ifp); */
393 		in6_ifdetach_destroy(ifp);
394 		mld_domifdetach(ifp);
395 	}
396 	IFNET_RUNLOCK();
397 
398 	/* Make sure any routes are gone as well. */
399 	rib_flush_routes_family(AF_INET6);
400 
401 	frag6_destroy();
402 	nd6_destroy();
403 	in6_ifattach_destroy();
404 
405 	hashdestroy(V_in6_ifaddrhashtbl, M_IFADDR, V_in6_ifaddrhmask);
406 }
407 
408 VNET_SYSUNINIT(inet6, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD, ip6_destroy, NULL);
409 #endif
410 
411 static int
412 ip6_input_hbh(struct mbuf **mp, uint32_t *plen, uint32_t *rtalert, int *off,
413     int *nxt, int *ours)
414 {
415 	struct mbuf *m;
416 	struct ip6_hdr *ip6;
417 	struct ip6_hbh *hbh;
418 
419 	if (ip6_hopopts_input(plen, rtalert, mp, off)) {
420 #if 0	/*touches NULL pointer*/
421 		in6_ifstat_inc((*mp)->m_pkthdr.rcvif, ifs6_in_discard);
422 #endif
423 		goto out;	/* m have already been freed */
424 	}
425 
426 	/* adjust pointer */
427 	m = *mp;
428 	ip6 = mtod(m, struct ip6_hdr *);
429 
430 	/*
431 	 * if the payload length field is 0 and the next header field
432 	 * indicates Hop-by-Hop Options header, then a Jumbo Payload
433 	 * option MUST be included.
434 	 */
435 	if (ip6->ip6_plen == 0 && *plen == 0) {
436 		/*
437 		 * Note that if a valid jumbo payload option is
438 		 * contained, ip6_hopopts_input() must set a valid
439 		 * (non-zero) payload length to the variable plen.
440 		 */
441 		IP6STAT_INC(ip6s_badoptions);
442 		in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
443 		in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_hdrerr);
444 		icmp6_error(m, ICMP6_PARAM_PROB,
445 			    ICMP6_PARAMPROB_HEADER,
446 			    (caddr_t)&ip6->ip6_plen - (caddr_t)ip6);
447 		goto out;
448 	}
449 	/* ip6_hopopts_input() ensures that mbuf is contiguous */
450 	hbh = (struct ip6_hbh *)(ip6 + 1);
451 	*nxt = hbh->ip6h_nxt;
452 
453 	/*
454 	 * If we are acting as a router and the packet contains a
455 	 * router alert option, see if we know the option value.
456 	 * Currently, we only support the option value for MLD, in which
457 	 * case we should pass the packet to the multicast routing
458 	 * daemon.
459 	 */
460 	if (*rtalert != ~0) {
461 		switch (*rtalert) {
462 		case IP6OPT_RTALERT_MLD:
463 			if (V_ip6_forwarding)
464 				*ours = 1;
465 			break;
466 		default:
467 			/*
468 			 * RFC2711 requires unrecognized values must be
469 			 * silently ignored.
470 			 */
471 			break;
472 		}
473 	}
474 
475 	return (0);
476 
477 out:
478 	return (1);
479 }
480 
481 #ifdef RSS
482 /*
483  * IPv6 direct input routine.
484  *
485  * This is called when reinjecting completed fragments where
486  * all of the previous checking and book-keeping has been done.
487  */
488 void
489 ip6_direct_input(struct mbuf *m)
490 {
491 	int off, nxt;
492 	int nest;
493 	struct m_tag *mtag;
494 	struct ip6_direct_ctx *ip6dc;
495 
496 	mtag = m_tag_locate(m, MTAG_ABI_IPV6, IPV6_TAG_DIRECT, NULL);
497 	KASSERT(mtag != NULL, ("Reinjected packet w/o direct ctx tag!"));
498 
499 	ip6dc = (struct ip6_direct_ctx *)(mtag + 1);
500 	nxt = ip6dc->ip6dc_nxt;
501 	off = ip6dc->ip6dc_off;
502 
503 	nest = 0;
504 
505 	m_tag_delete(m, mtag);
506 
507 	while (nxt != IPPROTO_DONE) {
508 		if (V_ip6_hdrnestlimit && (++nest > V_ip6_hdrnestlimit)) {
509 			IP6STAT_INC(ip6s_toomanyhdr);
510 			goto bad;
511 		}
512 
513 		/*
514 		 * protection against faulty packet - there should be
515 		 * more sanity checks in header chain processing.
516 		 */
517 		if (m->m_pkthdr.len < off) {
518 			IP6STAT_INC(ip6s_tooshort);
519 			in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_truncated);
520 			goto bad;
521 		}
522 
523 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
524 		if (IPSEC_ENABLED(ipv6)) {
525 			if (IPSEC_INPUT(ipv6, m, off, nxt) != 0)
526 				return;
527 		}
528 #endif /* IPSEC */
529 
530 		nxt = (*inet6sw[ip6_protox[nxt]].pr_input)(&m, &off, nxt);
531 	}
532 	return;
533 bad:
534 	m_freem(m);
535 }
536 #endif
537 
538 void
539 ip6_input(struct mbuf *m)
540 {
541 	struct in6_addr odst;
542 	struct ip6_hdr *ip6;
543 	struct in6_ifaddr *ia;
544 	struct ifnet *rcvif;
545 	u_int32_t plen;
546 	u_int32_t rtalert = ~0;
547 	int off = sizeof(struct ip6_hdr), nest;
548 	int nxt, ours = 0;
549 	int srcrt = 0;
550 
551 	/*
552 	 * Drop the packet if IPv6 operation is disabled on the interface.
553 	 */
554 	rcvif = m->m_pkthdr.rcvif;
555 	if ((ND_IFINFO(rcvif)->flags & ND6_IFF_IFDISABLED))
556 		goto bad;
557 
558 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
559 	/*
560 	 * should the inner packet be considered authentic?
561 	 * see comment in ah4_input().
562 	 * NB: m cannot be NULL when passed to the input routine
563 	 */
564 
565 	m->m_flags &= ~M_AUTHIPHDR;
566 	m->m_flags &= ~M_AUTHIPDGM;
567 
568 #endif /* IPSEC */
569 
570 	if (m->m_flags & M_FASTFWD_OURS) {
571 		/*
572 		 * Firewall changed destination to local.
573 		 */
574 		ip6 = mtod(m, struct ip6_hdr *);
575 		goto passin;
576 	}
577 
578 	/*
579 	 * mbuf statistics
580 	 */
581 	if (m->m_flags & M_EXT) {
582 		if (m->m_next)
583 			IP6STAT_INC(ip6s_mext2m);
584 		else
585 			IP6STAT_INC(ip6s_mext1);
586 	} else {
587 		if (m->m_next) {
588 			if (m->m_flags & M_LOOP) {
589 				IP6STAT_INC(ip6s_m2m[V_loif->if_index]);
590 			} else if (rcvif->if_index < IP6S_M2MMAX)
591 				IP6STAT_INC(ip6s_m2m[rcvif->if_index]);
592 			else
593 				IP6STAT_INC(ip6s_m2m[0]);
594 		} else
595 			IP6STAT_INC(ip6s_m1);
596 	}
597 
598 	in6_ifstat_inc(rcvif, ifs6_in_receive);
599 	IP6STAT_INC(ip6s_total);
600 
601 	/*
602 	 * L2 bridge code and some other code can return mbuf chain
603 	 * that does not conform to KAME requirement.  too bad.
604 	 * XXX: fails to join if interface MTU > MCLBYTES.  jumbogram?
605 	 */
606 	if (m && m->m_next != NULL && m->m_pkthdr.len < MCLBYTES) {
607 		struct mbuf *n;
608 
609 		if (m->m_pkthdr.len > MHLEN)
610 			n = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
611 		else
612 			n = m_gethdr(M_NOWAIT, MT_DATA);
613 		if (n == NULL)
614 			goto bad;
615 
616 		m_move_pkthdr(n, m);
617 		m_copydata(m, 0, n->m_pkthdr.len, mtod(n, caddr_t));
618 		n->m_len = n->m_pkthdr.len;
619 		m_freem(m);
620 		m = n;
621 	}
622 	if (m->m_len < sizeof(struct ip6_hdr)) {
623 		if ((m = m_pullup(m, sizeof(struct ip6_hdr))) == NULL) {
624 			IP6STAT_INC(ip6s_toosmall);
625 			in6_ifstat_inc(rcvif, ifs6_in_hdrerr);
626 			goto bad;
627 		}
628 	}
629 
630 	ip6 = mtod(m, struct ip6_hdr *);
631 	if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) {
632 		IP6STAT_INC(ip6s_badvers);
633 		in6_ifstat_inc(rcvif, ifs6_in_hdrerr);
634 		goto bad;
635 	}
636 
637 	IP6STAT_INC(ip6s_nxthist[ip6->ip6_nxt]);
638 	IP_PROBE(receive, NULL, NULL, ip6, rcvif, NULL, ip6);
639 
640 	/*
641 	 * Check against address spoofing/corruption.
642 	 */
643 	if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_src) ||
644 	    IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_dst)) {
645 		/*
646 		 * XXX: "badscope" is not very suitable for a multicast source.
647 		 */
648 		IP6STAT_INC(ip6s_badscope);
649 		in6_ifstat_inc(rcvif, ifs6_in_addrerr);
650 		goto bad;
651 	}
652 	if (IN6_IS_ADDR_MC_INTFACELOCAL(&ip6->ip6_dst) &&
653 	    !(m->m_flags & M_LOOP)) {
654 		/*
655 		 * In this case, the packet should come from the loopback
656 		 * interface.  However, we cannot just check the if_flags,
657 		 * because ip6_mloopback() passes the "actual" interface
658 		 * as the outgoing/incoming interface.
659 		 */
660 		IP6STAT_INC(ip6s_badscope);
661 		in6_ifstat_inc(rcvif, ifs6_in_addrerr);
662 		goto bad;
663 	}
664 	if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) &&
665 	    IPV6_ADDR_MC_SCOPE(&ip6->ip6_dst) == 0) {
666 		/*
667 		 * RFC4291 2.7:
668 		 * Nodes must not originate a packet to a multicast address
669 		 * whose scop field contains the reserved value 0; if such
670 		 * a packet is received, it must be silently dropped.
671 		 */
672 		IP6STAT_INC(ip6s_badscope);
673 		in6_ifstat_inc(rcvif, ifs6_in_addrerr);
674 		goto bad;
675 	}
676 #ifdef ALTQ
677 	if (altq_input != NULL && (*altq_input)(m, AF_INET6) == 0) {
678 		/* packet is dropped by traffic conditioner */
679 		return;
680 	}
681 #endif
682 	/*
683 	 * The following check is not documented in specs.  A malicious
684 	 * party may be able to use IPv4 mapped addr to confuse tcp/udp stack
685 	 * and bypass security checks (act as if it was from 127.0.0.1 by using
686 	 * IPv6 src ::ffff:127.0.0.1).  Be cautious.
687 	 *
688 	 * We have supported IPv6-only kernels for a few years and this issue
689 	 * has not come up.  The world seems to move mostly towards not using
690 	 * v4mapped on the wire, so it makes sense for us to keep rejecting
691 	 * any such packets.
692 	 */
693 	if (IN6_IS_ADDR_V4MAPPED(&ip6->ip6_src) ||
694 	    IN6_IS_ADDR_V4MAPPED(&ip6->ip6_dst)) {
695 		IP6STAT_INC(ip6s_badscope);
696 		in6_ifstat_inc(rcvif, ifs6_in_addrerr);
697 		goto bad;
698 	}
699 #if 0
700 	/*
701 	 * Reject packets with IPv4 compatible addresses (auto tunnel).
702 	 *
703 	 * The code forbids auto tunnel relay case in RFC1933 (the check is
704 	 * stronger than RFC1933).  We may want to re-enable it if mech-xx
705 	 * is revised to forbid relaying case.
706 	 */
707 	if (IN6_IS_ADDR_V4COMPAT(&ip6->ip6_src) ||
708 	    IN6_IS_ADDR_V4COMPAT(&ip6->ip6_dst)) {
709 		IP6STAT_INC(ip6s_badscope);
710 		in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
711 		goto bad;
712 	}
713 #endif
714 	/*
715 	 * Try to forward the packet, but if we fail continue.
716 	 * ip6_tryforward() does not generate redirects, so fall
717 	 * through to normal processing if redirects are required.
718 	 * ip6_tryforward() does inbound and outbound packet firewall
719 	 * processing. If firewall has decided that destination becomes
720 	 * our local address, it sets M_FASTFWD_OURS flag. In this
721 	 * case skip another inbound firewall processing and update
722 	 * ip6 pointer.
723 	 */
724 	if (V_ip6_forwarding != 0 && V_ip6_sendredirects == 0
725 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
726 	    && (!IPSEC_ENABLED(ipv6) ||
727 	    IPSEC_CAPS(ipv6, m, IPSEC_CAP_OPERABLE) == 0)
728 #endif
729 	    ) {
730 		if ((m = ip6_tryforward(m)) == NULL)
731 			return;
732 		if (m->m_flags & M_FASTFWD_OURS) {
733 			ip6 = mtod(m, struct ip6_hdr *);
734 			goto passin;
735 		}
736 	}
737 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
738 	/*
739 	 * Bypass packet filtering for packets previously handled by IPsec.
740 	 */
741 	if (IPSEC_ENABLED(ipv6) &&
742 	    IPSEC_CAPS(ipv6, m, IPSEC_CAP_BYPASS_FILTER) != 0)
743 			goto passin;
744 #endif
745 	/*
746 	 * Run through list of hooks for input packets.
747 	 *
748 	 * NB: Beware of the destination address changing
749 	 *     (e.g. by NAT rewriting).  When this happens,
750 	 *     tell ip6_forward to do the right thing.
751 	 */
752 
753 	/* Jump over all PFIL processing if hooks are not active. */
754 	if (!PFIL_HOOKED_IN(V_inet6_pfil_head))
755 		goto passin;
756 
757 	odst = ip6->ip6_dst;
758 	if (pfil_run_hooks(V_inet6_pfil_head, &m, m->m_pkthdr.rcvif, PFIL_IN,
759 	    NULL) != PFIL_PASS)
760 		return;
761 	ip6 = mtod(m, struct ip6_hdr *);
762 	srcrt = !IN6_ARE_ADDR_EQUAL(&odst, &ip6->ip6_dst);
763 	if ((m->m_flags & (M_IP6_NEXTHOP | M_FASTFWD_OURS)) == M_IP6_NEXTHOP &&
764 	    m_tag_find(m, PACKET_TAG_IPFORWARD, NULL) != NULL) {
765 		/*
766 		 * Directly ship the packet on.  This allows forwarding
767 		 * packets originally destined to us to some other directly
768 		 * connected host.
769 		 */
770 		ip6_forward(m, 1);
771 		return;
772 	}
773 
774 passin:
775 	/*
776 	 * Disambiguate address scope zones (if there is ambiguity).
777 	 * We first make sure that the original source or destination address
778 	 * is not in our internal form for scoped addresses.  Such addresses
779 	 * are not necessarily invalid spec-wise, but we cannot accept them due
780 	 * to the usage conflict.
781 	 * in6_setscope() then also checks and rejects the cases where src or
782 	 * dst are the loopback address and the receiving interface
783 	 * is not loopback.
784 	 */
785 	if (in6_clearscope(&ip6->ip6_src) || in6_clearscope(&ip6->ip6_dst)) {
786 		IP6STAT_INC(ip6s_badscope); /* XXX */
787 		goto bad;
788 	}
789 	if (in6_setscope(&ip6->ip6_src, rcvif, NULL) ||
790 	    in6_setscope(&ip6->ip6_dst, rcvif, NULL)) {
791 		IP6STAT_INC(ip6s_badscope);
792 		goto bad;
793 	}
794 	if (m->m_flags & M_FASTFWD_OURS) {
795 		m->m_flags &= ~M_FASTFWD_OURS;
796 		ours = 1;
797 		goto hbhcheck;
798 	}
799 	/*
800 	 * Multicast check. Assume packet is for us to avoid
801 	 * prematurely taking locks.
802 	 */
803 	if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
804 		ours = 1;
805 		in6_ifstat_inc(rcvif, ifs6_in_mcast);
806 		goto hbhcheck;
807 	}
808 	/*
809 	 * Unicast check
810 	 * XXX: For now we keep link-local IPv6 addresses with embedded
811 	 *      scope zone id, therefore we use zero zoneid here.
812 	 */
813 	ia = in6ifa_ifwithaddr(&ip6->ip6_dst, 0 /* XXX */, false);
814 	if (ia != NULL) {
815 		if (ia->ia6_flags & IN6_IFF_NOTREADY) {
816 			char ip6bufs[INET6_ADDRSTRLEN];
817 			char ip6bufd[INET6_ADDRSTRLEN];
818 			/* address is not ready, so discard the packet. */
819 			nd6log((LOG_INFO,
820 			    "ip6_input: packet to an unready address %s->%s\n",
821 			    ip6_sprintf(ip6bufs, &ip6->ip6_src),
822 			    ip6_sprintf(ip6bufd, &ip6->ip6_dst)));
823 			goto bad;
824 		}
825 		if (V_ip6_sav && !(rcvif->if_flags & IFF_LOOPBACK) &&
826 		    __predict_false(in6_localip_fib(&ip6->ip6_src,
827 			    rcvif->if_fib))) {
828 			IP6STAT_INC(ip6s_badscope); /* XXX */
829 			goto bad;
830 		}
831 		/* Count the packet in the ip address stats */
832 		counter_u64_add(ia->ia_ifa.ifa_ipackets, 1);
833 		counter_u64_add(ia->ia_ifa.ifa_ibytes, m->m_pkthdr.len);
834 		ours = 1;
835 		goto hbhcheck;
836 	}
837 
838 	/*
839 	 * Now there is no reason to process the packet if it's not our own
840 	 * and we're not a router.
841 	 */
842 	if (!V_ip6_forwarding) {
843 		IP6STAT_INC(ip6s_cantforward);
844 		goto bad;
845 	}
846 
847   hbhcheck:
848 	/*
849 	 * Process Hop-by-Hop options header if it's contained.
850 	 * m may be modified in ip6_hopopts_input().
851 	 * If a JumboPayload option is included, plen will also be modified.
852 	 */
853 	plen = (u_int32_t)ntohs(ip6->ip6_plen);
854 	if (ip6->ip6_nxt == IPPROTO_HOPOPTS) {
855 		if (ip6_input_hbh(&m, &plen, &rtalert, &off, &nxt, &ours) != 0)
856 			return;
857 	} else
858 		nxt = ip6->ip6_nxt;
859 
860 	/*
861 	 * Use mbuf flags to propagate Router Alert option to
862 	 * ICMPv6 layer, as hop-by-hop options have been stripped.
863 	 */
864 	if (rtalert != ~0)
865 		m->m_flags |= M_RTALERT_MLD;
866 
867 	/*
868 	 * Check that the amount of data in the buffers
869 	 * is as at least much as the IPv6 header would have us expect.
870 	 * Trim mbufs if longer than we expect.
871 	 * Drop packet if shorter than we expect.
872 	 */
873 	if (m->m_pkthdr.len - sizeof(struct ip6_hdr) < plen) {
874 		IP6STAT_INC(ip6s_tooshort);
875 		in6_ifstat_inc(rcvif, ifs6_in_truncated);
876 		goto bad;
877 	}
878 	if (m->m_pkthdr.len > sizeof(struct ip6_hdr) + plen) {
879 		if (m->m_len == m->m_pkthdr.len) {
880 			m->m_len = sizeof(struct ip6_hdr) + plen;
881 			m->m_pkthdr.len = sizeof(struct ip6_hdr) + plen;
882 		} else
883 			m_adj(m, sizeof(struct ip6_hdr) + plen - m->m_pkthdr.len);
884 	}
885 
886 	/*
887 	 * Forward if desirable.
888 	 */
889 	if (V_ip6_mrouter &&
890 	    IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
891 		/*
892 		 * If we are acting as a multicast router, all
893 		 * incoming multicast packets are passed to the
894 		 * kernel-level multicast forwarding function.
895 		 * The packet is returned (relatively) intact; if
896 		 * ip6_mforward() returns a non-zero value, the packet
897 		 * must be discarded, else it may be accepted below.
898 		 *
899 		 * XXX TODO: Check hlim and multicast scope here to avoid
900 		 * unnecessarily calling into ip6_mforward().
901 		 */
902 		if (ip6_mforward && ip6_mforward(ip6, rcvif, m)) {
903 			IP6STAT_INC(ip6s_cantforward);
904 			goto bad;
905 		}
906 	} else if (!ours) {
907 		ip6_forward(m, srcrt);
908 		return;
909 	}
910 
911 	/*
912 	 * Tell launch routine the next header
913 	 */
914 	IP6STAT_INC(ip6s_delivered);
915 	in6_ifstat_inc(rcvif, ifs6_in_deliver);
916 	nest = 0;
917 
918 	while (nxt != IPPROTO_DONE) {
919 		if (V_ip6_hdrnestlimit && (++nest > V_ip6_hdrnestlimit)) {
920 			IP6STAT_INC(ip6s_toomanyhdr);
921 			goto bad;
922 		}
923 
924 		/*
925 		 * protection against faulty packet - there should be
926 		 * more sanity checks in header chain processing.
927 		 */
928 		if (m->m_pkthdr.len < off) {
929 			IP6STAT_INC(ip6s_tooshort);
930 			in6_ifstat_inc(rcvif, ifs6_in_truncated);
931 			goto bad;
932 		}
933 
934 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
935 		if (IPSEC_ENABLED(ipv6)) {
936 			if (IPSEC_INPUT(ipv6, m, off, nxt) != 0)
937 				return;
938 		}
939 #endif /* IPSEC */
940 
941 		nxt = (*inet6sw[ip6_protox[nxt]].pr_input)(&m, &off, nxt);
942 	}
943 	return;
944 bad:
945 	in6_ifstat_inc(rcvif, ifs6_in_discard);
946 	if (m != NULL)
947 		m_freem(m);
948 }
949 
950 /*
951  * Hop-by-Hop options header processing. If a valid jumbo payload option is
952  * included, the real payload length will be stored in plenp.
953  *
954  * rtalertp - XXX: should be stored more smart way
955  */
956 static int
957 ip6_hopopts_input(u_int32_t *plenp, u_int32_t *rtalertp,
958     struct mbuf **mp, int *offp)
959 {
960 	struct mbuf *m = *mp;
961 	int off = *offp, hbhlen;
962 	struct ip6_hbh *hbh;
963 
964 	/* validation of the length of the header */
965 	if (m->m_len < off + sizeof(*hbh)) {
966 		m = m_pullup(m, off + sizeof(*hbh));
967 		if (m == NULL) {
968 			IP6STAT_INC(ip6s_exthdrtoolong);
969 			*mp = NULL;
970 			return (-1);
971 		}
972 	}
973 	hbh = (struct ip6_hbh *)(mtod(m, caddr_t) + off);
974 	hbhlen = (hbh->ip6h_len + 1) << 3;
975 
976 	if (m->m_len < off + hbhlen) {
977 		m = m_pullup(m, off + hbhlen);
978 		if (m == NULL) {
979 			IP6STAT_INC(ip6s_exthdrtoolong);
980 			*mp = NULL;
981 			return (-1);
982 		}
983 	}
984 	hbh = (struct ip6_hbh *)(mtod(m, caddr_t) + off);
985 	off += hbhlen;
986 	hbhlen -= sizeof(struct ip6_hbh);
987 	if (ip6_process_hopopts(m, (u_int8_t *)hbh + sizeof(struct ip6_hbh),
988 				hbhlen, rtalertp, plenp) < 0) {
989 		*mp = NULL;
990 		return (-1);
991 	}
992 
993 	*offp = off;
994 	*mp = m;
995 	return (0);
996 }
997 
998 /*
999  * Search header for all Hop-by-hop options and process each option.
1000  * This function is separate from ip6_hopopts_input() in order to
1001  * handle a case where the sending node itself process its hop-by-hop
1002  * options header. In such a case, the function is called from ip6_output().
1003  *
1004  * The function assumes that hbh header is located right after the IPv6 header
1005  * (RFC2460 p7), opthead is pointer into data content in m, and opthead to
1006  * opthead + hbhlen is located in contiguous memory region.
1007  */
1008 int
1009 ip6_process_hopopts(struct mbuf *m, u_int8_t *opthead, int hbhlen,
1010     u_int32_t *rtalertp, u_int32_t *plenp)
1011 {
1012 	struct ip6_hdr *ip6;
1013 	int optlen = 0;
1014 	u_int8_t *opt = opthead;
1015 	u_int16_t rtalert_val;
1016 	u_int32_t jumboplen;
1017 	const int erroff = sizeof(struct ip6_hdr) + sizeof(struct ip6_hbh);
1018 
1019 	for (; hbhlen > 0; hbhlen -= optlen, opt += optlen) {
1020 		switch (*opt) {
1021 		case IP6OPT_PAD1:
1022 			optlen = 1;
1023 			break;
1024 		case IP6OPT_PADN:
1025 			if (hbhlen < IP6OPT_MINLEN) {
1026 				IP6STAT_INC(ip6s_toosmall);
1027 				goto bad;
1028 			}
1029 			optlen = *(opt + 1) + 2;
1030 			break;
1031 		case IP6OPT_ROUTER_ALERT:
1032 			/* XXX may need check for alignment */
1033 			if (hbhlen < IP6OPT_RTALERT_LEN) {
1034 				IP6STAT_INC(ip6s_toosmall);
1035 				goto bad;
1036 			}
1037 			if (*(opt + 1) != IP6OPT_RTALERT_LEN - 2) {
1038 				/* XXX stat */
1039 				icmp6_error(m, ICMP6_PARAM_PROB,
1040 				    ICMP6_PARAMPROB_HEADER,
1041 				    erroff + opt + 1 - opthead);
1042 				return (-1);
1043 			}
1044 			optlen = IP6OPT_RTALERT_LEN;
1045 			bcopy((caddr_t)(opt + 2), (caddr_t)&rtalert_val, 2);
1046 			*rtalertp = ntohs(rtalert_val);
1047 			break;
1048 		case IP6OPT_JUMBO:
1049 			/* XXX may need check for alignment */
1050 			if (hbhlen < IP6OPT_JUMBO_LEN) {
1051 				IP6STAT_INC(ip6s_toosmall);
1052 				goto bad;
1053 			}
1054 			if (*(opt + 1) != IP6OPT_JUMBO_LEN - 2) {
1055 				/* XXX stat */
1056 				icmp6_error(m, ICMP6_PARAM_PROB,
1057 				    ICMP6_PARAMPROB_HEADER,
1058 				    erroff + opt + 1 - opthead);
1059 				return (-1);
1060 			}
1061 			optlen = IP6OPT_JUMBO_LEN;
1062 
1063 			/*
1064 			 * IPv6 packets that have non 0 payload length
1065 			 * must not contain a jumbo payload option.
1066 			 */
1067 			ip6 = mtod(m, struct ip6_hdr *);
1068 			if (ip6->ip6_plen) {
1069 				IP6STAT_INC(ip6s_badoptions);
1070 				icmp6_error(m, ICMP6_PARAM_PROB,
1071 				    ICMP6_PARAMPROB_HEADER,
1072 				    erroff + opt - opthead);
1073 				return (-1);
1074 			}
1075 
1076 			/*
1077 			 * We may see jumbolen in unaligned location, so
1078 			 * we'd need to perform bcopy().
1079 			 */
1080 			bcopy(opt + 2, &jumboplen, sizeof(jumboplen));
1081 			jumboplen = (u_int32_t)htonl(jumboplen);
1082 
1083 #if 1
1084 			/*
1085 			 * if there are multiple jumbo payload options,
1086 			 * *plenp will be non-zero and the packet will be
1087 			 * rejected.
1088 			 * the behavior may need some debate in ipngwg -
1089 			 * multiple options does not make sense, however,
1090 			 * there's no explicit mention in specification.
1091 			 */
1092 			if (*plenp != 0) {
1093 				IP6STAT_INC(ip6s_badoptions);
1094 				icmp6_error(m, ICMP6_PARAM_PROB,
1095 				    ICMP6_PARAMPROB_HEADER,
1096 				    erroff + opt + 2 - opthead);
1097 				return (-1);
1098 			}
1099 #endif
1100 
1101 			/*
1102 			 * jumbo payload length must be larger than 65535.
1103 			 */
1104 			if (jumboplen <= IPV6_MAXPACKET) {
1105 				IP6STAT_INC(ip6s_badoptions);
1106 				icmp6_error(m, ICMP6_PARAM_PROB,
1107 				    ICMP6_PARAMPROB_HEADER,
1108 				    erroff + opt + 2 - opthead);
1109 				return (-1);
1110 			}
1111 			*plenp = jumboplen;
1112 
1113 			break;
1114 		default:		/* unknown option */
1115 			if (hbhlen < IP6OPT_MINLEN) {
1116 				IP6STAT_INC(ip6s_toosmall);
1117 				goto bad;
1118 			}
1119 			optlen = ip6_unknown_opt(opt, m,
1120 			    erroff + opt - opthead);
1121 			if (optlen == -1)
1122 				return (-1);
1123 			optlen += 2;
1124 			break;
1125 		}
1126 	}
1127 
1128 	return (0);
1129 
1130   bad:
1131 	m_freem(m);
1132 	return (-1);
1133 }
1134 
1135 /*
1136  * Unknown option processing.
1137  * The third argument `off' is the offset from the IPv6 header to the option,
1138  * which is necessary if the IPv6 header the and option header and IPv6 header
1139  * is not contiguous in order to return an ICMPv6 error.
1140  */
1141 int
1142 ip6_unknown_opt(u_int8_t *optp, struct mbuf *m, int off)
1143 {
1144 	struct ip6_hdr *ip6;
1145 
1146 	switch (IP6OPT_TYPE(*optp)) {
1147 	case IP6OPT_TYPE_SKIP: /* ignore the option */
1148 		return ((int)*(optp + 1));
1149 	case IP6OPT_TYPE_DISCARD:	/* silently discard */
1150 		m_freem(m);
1151 		return (-1);
1152 	case IP6OPT_TYPE_FORCEICMP: /* send ICMP even if multicasted */
1153 		IP6STAT_INC(ip6s_badoptions);
1154 		icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_OPTION, off);
1155 		return (-1);
1156 	case IP6OPT_TYPE_ICMP: /* send ICMP if not multicasted */
1157 		IP6STAT_INC(ip6s_badoptions);
1158 		ip6 = mtod(m, struct ip6_hdr *);
1159 		if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) ||
1160 		    (m->m_flags & (M_BCAST|M_MCAST)))
1161 			m_freem(m);
1162 		else
1163 			icmp6_error(m, ICMP6_PARAM_PROB,
1164 				    ICMP6_PARAMPROB_OPTION, off);
1165 		return (-1);
1166 	}
1167 
1168 	m_freem(m);		/* XXX: NOTREACHED */
1169 	return (-1);
1170 }
1171 
1172 /*
1173  * Create the "control" list for this pcb.
1174  * These functions will not modify mbuf chain at all.
1175  *
1176  * The routine will be called from upper layer handlers like tcp6_input().
1177  * Thus the routine assumes that the caller (tcp6_input) have already
1178  * called m_pullup() and all the extension headers are located in the
1179  * very first mbuf on the mbuf chain.
1180  *
1181  * ip6_savecontrol_v4 will handle those options that are possible to be
1182  * set on a v4-mapped socket.
1183  * ip6_savecontrol will directly call ip6_savecontrol_v4 to handle those
1184  * options and handle the v6-only ones itself.
1185  */
1186 struct mbuf **
1187 ip6_savecontrol_v4(struct inpcb *inp, struct mbuf *m, struct mbuf **mp,
1188     int *v4only)
1189 {
1190 	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
1191 
1192 #ifdef SO_TIMESTAMP
1193 	if ((inp->inp_socket->so_options & SO_TIMESTAMP) != 0) {
1194 		union {
1195 			struct timeval tv;
1196 			struct bintime bt;
1197 			struct timespec ts;
1198 		} t;
1199 		struct bintime boottimebin, bt1;
1200 		struct timespec ts1;
1201 		bool stamped;
1202 
1203 		stamped = false;
1204 		switch (inp->inp_socket->so_ts_clock) {
1205 		case SO_TS_REALTIME_MICRO:
1206 			if ((m->m_flags & (M_PKTHDR | M_TSTMP)) == (M_PKTHDR |
1207 			    M_TSTMP)) {
1208 				mbuf_tstmp2timespec(m, &ts1);
1209 				timespec2bintime(&ts1, &bt1);
1210 				getboottimebin(&boottimebin);
1211 				bintime_add(&bt1, &boottimebin);
1212 				bintime2timeval(&bt1, &t.tv);
1213 			} else {
1214 				microtime(&t.tv);
1215 			}
1216 			*mp = sbcreatecontrol((caddr_t) &t.tv, sizeof(t.tv),
1217 			    SCM_TIMESTAMP, SOL_SOCKET);
1218 			if (*mp != NULL) {
1219 				mp = &(*mp)->m_next;
1220 				stamped = true;
1221 			}
1222 			break;
1223 
1224 		case SO_TS_BINTIME:
1225 			if ((m->m_flags & (M_PKTHDR | M_TSTMP)) == (M_PKTHDR |
1226 			    M_TSTMP)) {
1227 				mbuf_tstmp2timespec(m, &ts1);
1228 				timespec2bintime(&ts1, &t.bt);
1229 				getboottimebin(&boottimebin);
1230 				bintime_add(&t.bt, &boottimebin);
1231 			} else {
1232 				bintime(&t.bt);
1233 			}
1234 			*mp = sbcreatecontrol((caddr_t)&t.bt, sizeof(t.bt),
1235 			    SCM_BINTIME, SOL_SOCKET);
1236 			if (*mp != NULL) {
1237 				mp = &(*mp)->m_next;
1238 				stamped = true;
1239 			}
1240 			break;
1241 
1242 		case SO_TS_REALTIME:
1243 			if ((m->m_flags & (M_PKTHDR | M_TSTMP)) == (M_PKTHDR |
1244 			    M_TSTMP)) {
1245 				mbuf_tstmp2timespec(m, &t.ts);
1246 				getboottimebin(&boottimebin);
1247 				bintime2timespec(&boottimebin, &ts1);
1248 				timespecadd(&t.ts, &ts1, &t.ts);
1249 			} else {
1250 				nanotime(&t.ts);
1251 			}
1252 			*mp = sbcreatecontrol((caddr_t)&t.ts, sizeof(t.ts),
1253 			    SCM_REALTIME, SOL_SOCKET);
1254 			if (*mp != NULL) {
1255 				mp = &(*mp)->m_next;
1256 				stamped = true;
1257 			}
1258 			break;
1259 
1260 		case SO_TS_MONOTONIC:
1261 			if ((m->m_flags & (M_PKTHDR | M_TSTMP)) == (M_PKTHDR |
1262 			    M_TSTMP))
1263 				mbuf_tstmp2timespec(m, &t.ts);
1264 			else
1265 				nanouptime(&t.ts);
1266 			*mp = sbcreatecontrol((caddr_t)&t.ts, sizeof(t.ts),
1267 			    SCM_MONOTONIC, SOL_SOCKET);
1268 			if (*mp != NULL) {
1269 				mp = &(*mp)->m_next;
1270 				stamped = true;
1271 			}
1272 			break;
1273 
1274 		default:
1275 			panic("unknown (corrupted) so_ts_clock");
1276 		}
1277 		if (stamped && (m->m_flags & (M_PKTHDR | M_TSTMP)) ==
1278 		    (M_PKTHDR | M_TSTMP)) {
1279 			struct sock_timestamp_info sti;
1280 
1281 			bzero(&sti, sizeof(sti));
1282 			sti.st_info_flags = ST_INFO_HW;
1283 			if ((m->m_flags & M_TSTMP_HPREC) != 0)
1284 				sti.st_info_flags |= ST_INFO_HW_HPREC;
1285 			*mp = sbcreatecontrol((caddr_t)&sti, sizeof(sti),
1286 			    SCM_TIME_INFO, SOL_SOCKET);
1287 			if (*mp != NULL)
1288 				mp = &(*mp)->m_next;
1289 		}
1290 	}
1291 #endif
1292 
1293 #define IS2292(inp, x, y)	(((inp)->inp_flags & IN6P_RFC2292) ? (x) : (y))
1294 	/* RFC 2292 sec. 5 */
1295 	if ((inp->inp_flags & IN6P_PKTINFO) != 0) {
1296 		struct in6_pktinfo pi6;
1297 
1298 		if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) {
1299 #ifdef INET
1300 			struct ip *ip;
1301 
1302 			ip = mtod(m, struct ip *);
1303 			pi6.ipi6_addr.s6_addr32[0] = 0;
1304 			pi6.ipi6_addr.s6_addr32[1] = 0;
1305 			pi6.ipi6_addr.s6_addr32[2] = IPV6_ADDR_INT32_SMP;
1306 			pi6.ipi6_addr.s6_addr32[3] = ip->ip_dst.s_addr;
1307 #else
1308 			/* We won't hit this code */
1309 			bzero(&pi6.ipi6_addr, sizeof(struct in6_addr));
1310 #endif
1311 		} else {
1312 			bcopy(&ip6->ip6_dst, &pi6.ipi6_addr, sizeof(struct in6_addr));
1313 			in6_clearscope(&pi6.ipi6_addr);	/* XXX */
1314 		}
1315 		pi6.ipi6_ifindex =
1316 		    (m && m->m_pkthdr.rcvif) ? m->m_pkthdr.rcvif->if_index : 0;
1317 
1318 		*mp = sbcreatecontrol((caddr_t) &pi6,
1319 		    sizeof(struct in6_pktinfo),
1320 		    IS2292(inp, IPV6_2292PKTINFO, IPV6_PKTINFO), IPPROTO_IPV6);
1321 		if (*mp)
1322 			mp = &(*mp)->m_next;
1323 	}
1324 
1325 	if ((inp->inp_flags & IN6P_HOPLIMIT) != 0) {
1326 		int hlim;
1327 
1328 		if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) {
1329 #ifdef INET
1330 			struct ip *ip;
1331 
1332 			ip = mtod(m, struct ip *);
1333 			hlim = ip->ip_ttl;
1334 #else
1335 			/* We won't hit this code */
1336 			hlim = 0;
1337 #endif
1338 		} else {
1339 			hlim = ip6->ip6_hlim & 0xff;
1340 		}
1341 		*mp = sbcreatecontrol((caddr_t) &hlim, sizeof(int),
1342 		    IS2292(inp, IPV6_2292HOPLIMIT, IPV6_HOPLIMIT),
1343 		    IPPROTO_IPV6);
1344 		if (*mp)
1345 			mp = &(*mp)->m_next;
1346 	}
1347 
1348 	if ((inp->inp_flags & IN6P_TCLASS) != 0) {
1349 		int tclass;
1350 
1351 		if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) {
1352 #ifdef INET
1353 			struct ip *ip;
1354 
1355 			ip = mtod(m, struct ip *);
1356 			tclass = ip->ip_tos;
1357 #else
1358 			/* We won't hit this code */
1359 			tclass = 0;
1360 #endif
1361 		} else {
1362 			u_int32_t flowinfo;
1363 
1364 			flowinfo = (u_int32_t)ntohl(ip6->ip6_flow & IPV6_FLOWINFO_MASK);
1365 			flowinfo >>= 20;
1366 			tclass = flowinfo & 0xff;
1367 		}
1368 		*mp = sbcreatecontrol((caddr_t) &tclass, sizeof(int),
1369 		    IPV6_TCLASS, IPPROTO_IPV6);
1370 		if (*mp)
1371 			mp = &(*mp)->m_next;
1372 	}
1373 
1374 	if (v4only != NULL) {
1375 		if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) {
1376 			*v4only = 1;
1377 		} else {
1378 			*v4only = 0;
1379 		}
1380 	}
1381 
1382 	return (mp);
1383 }
1384 
1385 void
1386 ip6_savecontrol(struct inpcb *inp, struct mbuf *m, struct mbuf **mp)
1387 {
1388 	struct ip6_hdr *ip6;
1389 	int v4only = 0;
1390 
1391 	mp = ip6_savecontrol_v4(inp, m, mp, &v4only);
1392 	if (v4only)
1393 		return;
1394 
1395 	ip6 = mtod(m, struct ip6_hdr *);
1396 	/*
1397 	 * IPV6_HOPOPTS socket option.  Recall that we required super-user
1398 	 * privilege for the option (see ip6_ctloutput), but it might be too
1399 	 * strict, since there might be some hop-by-hop options which can be
1400 	 * returned to normal user.
1401 	 * See also RFC 2292 section 6 (or RFC 3542 section 8).
1402 	 */
1403 	if ((inp->inp_flags & IN6P_HOPOPTS) != 0) {
1404 		/*
1405 		 * Check if a hop-by-hop options header is contatined in the
1406 		 * received packet, and if so, store the options as ancillary
1407 		 * data. Note that a hop-by-hop options header must be
1408 		 * just after the IPv6 header, which is assured through the
1409 		 * IPv6 input processing.
1410 		 */
1411 		if (ip6->ip6_nxt == IPPROTO_HOPOPTS) {
1412 			struct ip6_hbh *hbh;
1413 			int hbhlen;
1414 
1415 			hbh = (struct ip6_hbh *)(ip6 + 1);
1416 			hbhlen = (hbh->ip6h_len + 1) << 3;
1417 
1418 			/*
1419 			 * XXX: We copy the whole header even if a
1420 			 * jumbo payload option is included, the option which
1421 			 * is to be removed before returning according to
1422 			 * RFC2292.
1423 			 * Note: this constraint is removed in RFC3542
1424 			 */
1425 			*mp = sbcreatecontrol((caddr_t)hbh, hbhlen,
1426 			    IS2292(inp, IPV6_2292HOPOPTS, IPV6_HOPOPTS),
1427 			    IPPROTO_IPV6);
1428 			if (*mp)
1429 				mp = &(*mp)->m_next;
1430 		}
1431 	}
1432 
1433 	if ((inp->inp_flags & (IN6P_RTHDR | IN6P_DSTOPTS)) != 0) {
1434 		int nxt = ip6->ip6_nxt, off = sizeof(struct ip6_hdr);
1435 
1436 		/*
1437 		 * Search for destination options headers or routing
1438 		 * header(s) through the header chain, and stores each
1439 		 * header as ancillary data.
1440 		 * Note that the order of the headers remains in
1441 		 * the chain of ancillary data.
1442 		 */
1443 		while (1) {	/* is explicit loop prevention necessary? */
1444 			struct ip6_ext *ip6e = NULL;
1445 			int elen;
1446 
1447 			/*
1448 			 * if it is not an extension header, don't try to
1449 			 * pull it from the chain.
1450 			 */
1451 			switch (nxt) {
1452 			case IPPROTO_DSTOPTS:
1453 			case IPPROTO_ROUTING:
1454 			case IPPROTO_HOPOPTS:
1455 			case IPPROTO_AH: /* is it possible? */
1456 				break;
1457 			default:
1458 				goto loopend;
1459 			}
1460 
1461 			if (off + sizeof(*ip6e) > m->m_len)
1462 				goto loopend;
1463 			ip6e = (struct ip6_ext *)(mtod(m, caddr_t) + off);
1464 			if (nxt == IPPROTO_AH)
1465 				elen = (ip6e->ip6e_len + 2) << 2;
1466 			else
1467 				elen = (ip6e->ip6e_len + 1) << 3;
1468 			if (off + elen > m->m_len)
1469 				goto loopend;
1470 
1471 			switch (nxt) {
1472 			case IPPROTO_DSTOPTS:
1473 				if (!(inp->inp_flags & IN6P_DSTOPTS))
1474 					break;
1475 
1476 				*mp = sbcreatecontrol((caddr_t)ip6e, elen,
1477 				    IS2292(inp,
1478 					IPV6_2292DSTOPTS, IPV6_DSTOPTS),
1479 				    IPPROTO_IPV6);
1480 				if (*mp)
1481 					mp = &(*mp)->m_next;
1482 				break;
1483 			case IPPROTO_ROUTING:
1484 				if (!(inp->inp_flags & IN6P_RTHDR))
1485 					break;
1486 
1487 				*mp = sbcreatecontrol((caddr_t)ip6e, elen,
1488 				    IS2292(inp, IPV6_2292RTHDR, IPV6_RTHDR),
1489 				    IPPROTO_IPV6);
1490 				if (*mp)
1491 					mp = &(*mp)->m_next;
1492 				break;
1493 			case IPPROTO_HOPOPTS:
1494 			case IPPROTO_AH: /* is it possible? */
1495 				break;
1496 
1497 			default:
1498 				/*
1499 				 * other cases have been filtered in the above.
1500 				 * none will visit this case.  here we supply
1501 				 * the code just in case (nxt overwritten or
1502 				 * other cases).
1503 				 */
1504 				goto loopend;
1505 			}
1506 
1507 			/* proceed with the next header. */
1508 			off += elen;
1509 			nxt = ip6e->ip6e_nxt;
1510 			ip6e = NULL;
1511 		}
1512 	  loopend:
1513 		;
1514 	}
1515 
1516 	if (inp->inp_flags2 & INP_RECVFLOWID) {
1517 		uint32_t flowid, flow_type;
1518 
1519 		flowid = m->m_pkthdr.flowid;
1520 		flow_type = M_HASHTYPE_GET(m);
1521 
1522 		/*
1523 		 * XXX should handle the failure of one or the
1524 		 * other - don't populate both?
1525 		 */
1526 		*mp = sbcreatecontrol((caddr_t) &flowid,
1527 		    sizeof(uint32_t), IPV6_FLOWID, IPPROTO_IPV6);
1528 		if (*mp)
1529 			mp = &(*mp)->m_next;
1530 		*mp = sbcreatecontrol((caddr_t) &flow_type,
1531 		    sizeof(uint32_t), IPV6_FLOWTYPE, IPPROTO_IPV6);
1532 		if (*mp)
1533 			mp = &(*mp)->m_next;
1534 	}
1535 
1536 #ifdef	RSS
1537 	if (inp->inp_flags2 & INP_RECVRSSBUCKETID) {
1538 		uint32_t flowid, flow_type;
1539 		uint32_t rss_bucketid;
1540 
1541 		flowid = m->m_pkthdr.flowid;
1542 		flow_type = M_HASHTYPE_GET(m);
1543 
1544 		if (rss_hash2bucket(flowid, flow_type, &rss_bucketid) == 0) {
1545 			*mp = sbcreatecontrol((caddr_t) &rss_bucketid,
1546 			   sizeof(uint32_t), IPV6_RSSBUCKETID, IPPROTO_IPV6);
1547 			if (*mp)
1548 				mp = &(*mp)->m_next;
1549 		}
1550 	}
1551 #endif
1552 
1553 }
1554 #undef IS2292
1555 
1556 void
1557 ip6_notify_pmtu(struct inpcb *inp, struct sockaddr_in6 *dst, u_int32_t mtu)
1558 {
1559 	struct socket *so;
1560 	struct mbuf *m_mtu;
1561 	struct ip6_mtuinfo mtuctl;
1562 
1563 	KASSERT(inp != NULL, ("%s: inp == NULL", __func__));
1564 	/*
1565 	 * Notify the error by sending IPV6_PATHMTU ancillary data if
1566 	 * application wanted to know the MTU value.
1567 	 * NOTE: we notify disconnected sockets, because some udp
1568 	 * applications keep sending sockets disconnected.
1569 	 * NOTE: our implementation doesn't notify connected sockets that has
1570 	 * foreign address that is different than given destination addresses
1571 	 * (this is permitted by RFC 3542).
1572 	 */
1573 	if ((inp->inp_flags & IN6P_MTU) == 0 || (
1574 	    !IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr) &&
1575 	    !IN6_ARE_ADDR_EQUAL(&inp->in6p_faddr, &dst->sin6_addr)))
1576 		return;
1577 
1578 	mtuctl.ip6m_mtu = mtu;
1579 	mtuctl.ip6m_addr = *dst;
1580 	if (sa6_recoverscope(&mtuctl.ip6m_addr))
1581 		return;
1582 
1583 	if ((m_mtu = sbcreatecontrol((caddr_t)&mtuctl, sizeof(mtuctl),
1584 	    IPV6_PATHMTU, IPPROTO_IPV6)) == NULL)
1585 		return;
1586 
1587 	so =  inp->inp_socket;
1588 	if (sbappendaddr(&so->so_rcv, (struct sockaddr *)dst, NULL, m_mtu)
1589 	    == 0) {
1590 		soroverflow(so);
1591 		m_freem(m_mtu);
1592 		/* XXX: should count statistics */
1593 	} else
1594 		sorwakeup(so);
1595 }
1596 
1597 /*
1598  * Get pointer to the previous header followed by the header
1599  * currently processed.
1600  */
1601 int
1602 ip6_get_prevhdr(const struct mbuf *m, int off)
1603 {
1604 	struct ip6_ext ip6e;
1605 	struct ip6_hdr *ip6;
1606 	int len, nlen, nxt;
1607 
1608 	if (off == sizeof(struct ip6_hdr))
1609 		return (offsetof(struct ip6_hdr, ip6_nxt));
1610 	if (off < sizeof(struct ip6_hdr))
1611 		panic("%s: off < sizeof(struct ip6_hdr)", __func__);
1612 
1613 	ip6 = mtod(m, struct ip6_hdr *);
1614 	nxt = ip6->ip6_nxt;
1615 	len = sizeof(struct ip6_hdr);
1616 	nlen = 0;
1617 	while (len < off) {
1618 		m_copydata(m, len, sizeof(ip6e), (caddr_t)&ip6e);
1619 		switch (nxt) {
1620 		case IPPROTO_FRAGMENT:
1621 			nlen = sizeof(struct ip6_frag);
1622 			break;
1623 		case IPPROTO_AH:
1624 			nlen = (ip6e.ip6e_len + 2) << 2;
1625 			break;
1626 		default:
1627 			nlen = (ip6e.ip6e_len + 1) << 3;
1628 		}
1629 		len += nlen;
1630 		nxt = ip6e.ip6e_nxt;
1631 	}
1632 	return (len - nlen);
1633 }
1634 
1635 /*
1636  * get next header offset.  m will be retained.
1637  */
1638 int
1639 ip6_nexthdr(const struct mbuf *m, int off, int proto, int *nxtp)
1640 {
1641 	struct ip6_hdr ip6;
1642 	struct ip6_ext ip6e;
1643 	struct ip6_frag fh;
1644 
1645 	/* just in case */
1646 	if (m == NULL)
1647 		panic("ip6_nexthdr: m == NULL");
1648 	if ((m->m_flags & M_PKTHDR) == 0 || m->m_pkthdr.len < off)
1649 		return -1;
1650 
1651 	switch (proto) {
1652 	case IPPROTO_IPV6:
1653 		if (m->m_pkthdr.len < off + sizeof(ip6))
1654 			return -1;
1655 		m_copydata(m, off, sizeof(ip6), (caddr_t)&ip6);
1656 		if (nxtp)
1657 			*nxtp = ip6.ip6_nxt;
1658 		off += sizeof(ip6);
1659 		return off;
1660 
1661 	case IPPROTO_FRAGMENT:
1662 		/*
1663 		 * terminate parsing if it is not the first fragment,
1664 		 * it does not make sense to parse through it.
1665 		 */
1666 		if (m->m_pkthdr.len < off + sizeof(fh))
1667 			return -1;
1668 		m_copydata(m, off, sizeof(fh), (caddr_t)&fh);
1669 		/* IP6F_OFF_MASK = 0xfff8(BigEndian), 0xf8ff(LittleEndian) */
1670 		if (fh.ip6f_offlg & IP6F_OFF_MASK)
1671 			return -1;
1672 		if (nxtp)
1673 			*nxtp = fh.ip6f_nxt;
1674 		off += sizeof(struct ip6_frag);
1675 		return off;
1676 
1677 	case IPPROTO_AH:
1678 		if (m->m_pkthdr.len < off + sizeof(ip6e))
1679 			return -1;
1680 		m_copydata(m, off, sizeof(ip6e), (caddr_t)&ip6e);
1681 		if (nxtp)
1682 			*nxtp = ip6e.ip6e_nxt;
1683 		off += (ip6e.ip6e_len + 2) << 2;
1684 		return off;
1685 
1686 	case IPPROTO_HOPOPTS:
1687 	case IPPROTO_ROUTING:
1688 	case IPPROTO_DSTOPTS:
1689 		if (m->m_pkthdr.len < off + sizeof(ip6e))
1690 			return -1;
1691 		m_copydata(m, off, sizeof(ip6e), (caddr_t)&ip6e);
1692 		if (nxtp)
1693 			*nxtp = ip6e.ip6e_nxt;
1694 		off += (ip6e.ip6e_len + 1) << 3;
1695 		return off;
1696 
1697 	case IPPROTO_NONE:
1698 	case IPPROTO_ESP:
1699 	case IPPROTO_IPCOMP:
1700 		/* give up */
1701 		return -1;
1702 
1703 	default:
1704 		return -1;
1705 	}
1706 
1707 	/* NOTREACHED */
1708 }
1709 
1710 /*
1711  * get offset for the last header in the chain.  m will be kept untainted.
1712  */
1713 int
1714 ip6_lasthdr(const struct mbuf *m, int off, int proto, int *nxtp)
1715 {
1716 	int newoff;
1717 	int nxt;
1718 
1719 	if (!nxtp) {
1720 		nxt = -1;
1721 		nxtp = &nxt;
1722 	}
1723 	while (1) {
1724 		newoff = ip6_nexthdr(m, off, proto, nxtp);
1725 		if (newoff < 0)
1726 			return off;
1727 		else if (newoff < off)
1728 			return -1;	/* invalid */
1729 		else if (newoff == off)
1730 			return newoff;
1731 
1732 		off = newoff;
1733 		proto = *nxtp;
1734 	}
1735 }
1736 
1737 /*
1738  * System control for IP6
1739  */
1740 
1741 u_char	inet6ctlerrmap[PRC_NCMDS] = {
1742 	0,		0,		0,		0,
1743 	0,		EMSGSIZE,	EHOSTDOWN,	EHOSTUNREACH,
1744 	EHOSTUNREACH,	EHOSTUNREACH,	ECONNREFUSED,	ECONNREFUSED,
1745 	EMSGSIZE,	EHOSTUNREACH,	0,		0,
1746 	0,		0,		EHOSTUNREACH,	0,
1747 	ENOPROTOOPT,	ECONNREFUSED
1748 };
1749