1/*-
2 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the project nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 *	$KAME: ip6_input.c,v 1.259 2002/01/21 04:58:09 jinmei Exp $
30 */
31
32/*-
33 * Copyright (c) 1982, 1986, 1988, 1993
34 *	The Regents of the University of California.  All rights reserved.
35 *
36 * Redistribution and use in source and binary forms, with or without
37 * modification, are permitted provided that the following conditions
38 * are met:
39 * 1. Redistributions of source code must retain the above copyright
40 *    notice, this list of conditions and the following disclaimer.
41 * 2. Redistributions in binary form must reproduce the above copyright
42 *    notice, this list of conditions and the following disclaimer in the
43 *    documentation and/or other materials provided with the distribution.
44 * 4. Neither the name of the University nor the names of its contributors
45 *    may be used to endorse or promote products derived from this software
46 *    without specific prior written permission.
47 *
48 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
49 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
50 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
51 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
52 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
53 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
54 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
55 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
56 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
57 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
58 * SUCH DAMAGE.
59 *
60 *	@(#)ip_input.c	8.2 (Berkeley) 1/4/94
61 */
62
63#include <sys/cdefs.h>
64__FBSDID("$FreeBSD: releng/10.3/sys/netinet6/ip6_input.c 279911 2015-03-12 09:04:19Z ae $");
65
66#include "opt_inet.h"
67#include "opt_inet6.h"
68#include "opt_ipfw.h"
69#include "opt_ipsec.h"
70#include "opt_kdtrace.h"
71#include "opt_route.h"
72
73#include <sys/param.h>
74#include <sys/systm.h>
75#include <sys/malloc.h>
76#include <sys/mbuf.h>
77#include <sys/proc.h>
78#include <sys/domain.h>
79#include <sys/protosw.h>
80#include <sys/sdt.h>
81#include <sys/socket.h>
82#include <sys/socketvar.h>
83#include <sys/errno.h>
84#include <sys/time.h>
85#include <sys/kernel.h>
86#include <sys/syslog.h>
87
88#include <net/if.h>
89#include <net/if_types.h>
90#include <net/if_dl.h>
91#include <net/route.h>
92#include <net/netisr.h>
93#include <net/pfil.h>
94#include <net/vnet.h>
95
96#include <netinet/in.h>
97#include <netinet/in_kdtrace.h>
98#include <netinet/ip_var.h>
99#include <netinet/in_systm.h>
100#include <net/if_llatbl.h>
101#ifdef INET
102#include <netinet/ip.h>
103#include <netinet/ip_icmp.h>
104#endif /* INET */
105#include <netinet/ip6.h>
106#include <netinet6/in6_var.h>
107#include <netinet6/ip6_var.h>
108#include <netinet/in_pcb.h>
109#include <netinet/icmp6.h>
110#include <netinet6/scope6_var.h>
111#include <netinet6/in6_ifattach.h>
112#include <netinet6/nd6.h>
113
114#ifdef IPSEC
115#include <netipsec/ipsec.h>
116#include <netinet6/ip6_ipsec.h>
117#include <netipsec/ipsec6.h>
118#endif /* IPSEC */
119
120#include <netinet6/ip6protosw.h>
121
122extern struct domain inet6domain;
123
124u_char ip6_protox[IPPROTO_MAX];
125VNET_DEFINE(struct in6_ifaddrhead, in6_ifaddrhead);
126VNET_DEFINE(struct in6_ifaddrlisthead *, in6_ifaddrhashtbl);
127VNET_DEFINE(u_long, in6_ifaddrhmask);
128
129static struct netisr_handler ip6_nh = {
130	.nh_name = "ip6",
131	.nh_handler = ip6_input,
132	.nh_proto = NETISR_IPV6,
133	.nh_policy = NETISR_POLICY_FLOW,
134};
135
136VNET_DECLARE(struct callout, in6_tmpaddrtimer_ch);
137#define	V_in6_tmpaddrtimer_ch		VNET(in6_tmpaddrtimer_ch)
138
139VNET_DEFINE(struct pfil_head, inet6_pfil_hook);
140
141VNET_PCPUSTAT_DEFINE(struct ip6stat, ip6stat);
142VNET_PCPUSTAT_SYSINIT(ip6stat);
143#ifdef VIMAGE
144VNET_PCPUSTAT_SYSUNINIT(ip6stat);
145#endif /* VIMAGE */
146
147struct rwlock in6_ifaddr_lock;
148RW_SYSINIT(in6_ifaddr_lock, &in6_ifaddr_lock, "in6_ifaddr_lock");
149
150static void ip6_init2(void *);
151static struct ip6aux *ip6_setdstifaddr(struct mbuf *, struct in6_ifaddr *);
152static struct ip6aux *ip6_addaux(struct mbuf *);
153static struct ip6aux *ip6_findaux(struct mbuf *m);
154static void ip6_delaux (struct mbuf *);
155static int ip6_hopopts_input(u_int32_t *, u_int32_t *, struct mbuf **, int *);
156#ifdef PULLDOWN_TEST
157static struct mbuf *ip6_pullexthdr(struct mbuf *, size_t, int);
158#endif
159
160/*
161 * IP6 initialization: fill in IP6 protocol switch table.
162 * All protocols not implemented in kernel go to raw IP6 protocol handler.
163 */
164void
165ip6_init(void)
166{
167	struct ip6protosw *pr;
168	int i;
169
170	TUNABLE_INT_FETCH("net.inet6.ip6.auto_linklocal",
171	    &V_ip6_auto_linklocal);
172	TUNABLE_INT_FETCH("net.inet6.ip6.accept_rtadv", &V_ip6_accept_rtadv);
173	TUNABLE_INT_FETCH("net.inet6.ip6.no_radr", &V_ip6_no_radr);
174
175	TAILQ_INIT(&V_in6_ifaddrhead);
176	V_in6_ifaddrhashtbl = hashinit(IN6ADDR_NHASH, M_IFADDR,
177	    &V_in6_ifaddrhmask);
178
179	/* Initialize packet filter hooks. */
180	V_inet6_pfil_hook.ph_type = PFIL_TYPE_AF;
181	V_inet6_pfil_hook.ph_af = AF_INET6;
182	if ((i = pfil_head_register(&V_inet6_pfil_hook)) != 0)
183		printf("%s: WARNING: unable to register pfil hook, "
184			"error %d\n", __func__, i);
185
186	scope6_init();
187	addrsel_policy_init();
188	nd6_init();
189	frag6_init();
190
191	V_ip6_desync_factor = arc4random() % MAX_TEMP_DESYNC_FACTOR;
192
193	/* Skip global initialization stuff for non-default instances. */
194	if (!IS_DEFAULT_VNET(curvnet))
195		return;
196
197#ifdef DIAGNOSTIC
198	if (sizeof(struct protosw) != sizeof(struct ip6protosw))
199		panic("sizeof(protosw) != sizeof(ip6protosw)");
200#endif
201	pr = (struct ip6protosw *)pffindproto(PF_INET6, IPPROTO_RAW, SOCK_RAW);
202	if (pr == NULL)
203		panic("ip6_init");
204
205	/* Initialize the entire ip6_protox[] array to IPPROTO_RAW. */
206	for (i = 0; i < IPPROTO_MAX; i++)
207		ip6_protox[i] = pr - inet6sw;
208	/*
209	 * Cycle through IP protocols and put them into the appropriate place
210	 * in ip6_protox[].
211	 */
212	for (pr = (struct ip6protosw *)inet6domain.dom_protosw;
213	    pr < (struct ip6protosw *)inet6domain.dom_protoswNPROTOSW; pr++)
214		if (pr->pr_domain->dom_family == PF_INET6 &&
215		    pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) {
216			/* Be careful to only index valid IP protocols. */
217			if (pr->pr_protocol < IPPROTO_MAX)
218				ip6_protox[pr->pr_protocol] = pr - inet6sw;
219		}
220
221	netisr_register(&ip6_nh);
222}
223
224/*
225 * The protocol to be inserted into ip6_protox[] must be already registered
226 * in inet6sw[], either statically or through pf_proto_register().
227 */
228int
229ip6proto_register(short ip6proto)
230{
231	struct ip6protosw *pr;
232
233	/* Sanity checks. */
234	if (ip6proto <= 0 || ip6proto >= IPPROTO_MAX)
235		return (EPROTONOSUPPORT);
236
237	/*
238	 * The protocol slot must not be occupied by another protocol
239	 * already.  An index pointing to IPPROTO_RAW is unused.
240	 */
241	pr = (struct ip6protosw *)pffindproto(PF_INET6, IPPROTO_RAW, SOCK_RAW);
242	if (pr == NULL)
243		return (EPFNOSUPPORT);
244	if (ip6_protox[ip6proto] != pr - inet6sw)	/* IPPROTO_RAW */
245		return (EEXIST);
246
247	/*
248	 * Find the protocol position in inet6sw[] and set the index.
249	 */
250	for (pr = (struct ip6protosw *)inet6domain.dom_protosw;
251	    pr < (struct ip6protosw *)inet6domain.dom_protoswNPROTOSW; pr++) {
252		if (pr->pr_domain->dom_family == PF_INET6 &&
253		    pr->pr_protocol && pr->pr_protocol == ip6proto) {
254			ip6_protox[pr->pr_protocol] = pr - inet6sw;
255			return (0);
256		}
257	}
258	return (EPROTONOSUPPORT);
259}
260
261int
262ip6proto_unregister(short ip6proto)
263{
264	struct ip6protosw *pr;
265
266	/* Sanity checks. */
267	if (ip6proto <= 0 || ip6proto >= IPPROTO_MAX)
268		return (EPROTONOSUPPORT);
269
270	/* Check if the protocol was indeed registered. */
271	pr = (struct ip6protosw *)pffindproto(PF_INET6, IPPROTO_RAW, SOCK_RAW);
272	if (pr == NULL)
273		return (EPFNOSUPPORT);
274	if (ip6_protox[ip6proto] == pr - inet6sw)	/* IPPROTO_RAW */
275		return (ENOENT);
276
277	/* Reset the protocol slot to IPPROTO_RAW. */
278	ip6_protox[ip6proto] = pr - inet6sw;
279	return (0);
280}
281
282#ifdef VIMAGE
283void
284ip6_destroy()
285{
286	int i;
287
288	if ((i = pfil_head_unregister(&V_inet6_pfil_hook)) != 0)
289		printf("%s: WARNING: unable to unregister pfil hook, "
290		    "error %d\n", __func__, i);
291	hashdestroy(V_in6_ifaddrhashtbl, M_IFADDR, V_in6_ifaddrhmask);
292	nd6_destroy();
293	callout_drain(&V_in6_tmpaddrtimer_ch);
294}
295#endif
296
297static int
298ip6_init2_vnet(const void *unused __unused)
299{
300
301	/* nd6_timer_init */
302	callout_init(&V_nd6_timer_ch, 0);
303	callout_reset(&V_nd6_timer_ch, hz, nd6_timer, curvnet);
304
305	/* timer for regeneranation of temporary addresses randomize ID */
306	callout_init(&V_in6_tmpaddrtimer_ch, 0);
307	callout_reset(&V_in6_tmpaddrtimer_ch,
308		      (V_ip6_temp_preferred_lifetime - V_ip6_desync_factor -
309		       V_ip6_temp_regen_advance) * hz,
310		      in6_tmpaddrtimer, curvnet);
311
312	return (0);
313}
314
315static void
316ip6_init2(void *dummy)
317{
318
319	ip6_init2_vnet(NULL);
320}
321
322/* cheat */
323/* This must be after route_init(), which is now SI_ORDER_THIRD */
324SYSINIT(netinet6init2, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, ip6_init2, NULL);
325
326static int
327ip6_input_hbh(struct mbuf *m, uint32_t *plen, uint32_t *rtalert, int *off,
328    int *nxt, int *ours)
329{
330	struct ip6_hdr *ip6;
331	struct ip6_hbh *hbh;
332
333	if (ip6_hopopts_input(plen, rtalert, &m, off)) {
334#if 0	/*touches NULL pointer*/
335		in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
336#endif
337		goto out;	/* m have already been freed */
338	}
339
340	/* adjust pointer */
341	ip6 = mtod(m, struct ip6_hdr *);
342
343	/*
344	 * if the payload length field is 0 and the next header field
345	 * indicates Hop-by-Hop Options header, then a Jumbo Payload
346	 * option MUST be included.
347	 */
348	if (ip6->ip6_plen == 0 && *plen == 0) {
349		/*
350		 * Note that if a valid jumbo payload option is
351		 * contained, ip6_hopopts_input() must set a valid
352		 * (non-zero) payload length to the variable plen.
353		 */
354		IP6STAT_INC(ip6s_badoptions);
355		in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
356		in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_hdrerr);
357		icmp6_error(m, ICMP6_PARAM_PROB,
358			    ICMP6_PARAMPROB_HEADER,
359			    (caddr_t)&ip6->ip6_plen - (caddr_t)ip6);
360		goto out;
361	}
362#ifndef PULLDOWN_TEST
363	/* ip6_hopopts_input() ensures that mbuf is contiguous */
364	hbh = (struct ip6_hbh *)(ip6 + 1);
365#else
366	IP6_EXTHDR_GET(hbh, struct ip6_hbh *, m, sizeof(struct ip6_hdr),
367		sizeof(struct ip6_hbh));
368	if (hbh == NULL) {
369		IP6STAT_INC(ip6s_tooshort);
370		goto out;
371	}
372#endif
373	*nxt = hbh->ip6h_nxt;
374
375	/*
376	 * If we are acting as a router and the packet contains a
377	 * router alert option, see if we know the option value.
378	 * Currently, we only support the option value for MLD, in which
379	 * case we should pass the packet to the multicast routing
380	 * daemon.
381	 */
382	if (*rtalert != ~0) {
383		switch (*rtalert) {
384		case IP6OPT_RTALERT_MLD:
385			if (V_ip6_forwarding)
386				*ours = 1;
387			break;
388		default:
389			/*
390			 * RFC2711 requires unrecognized values must be
391			 * silently ignored.
392			 */
393			break;
394		}
395	}
396
397	return (0);
398
399out:
400	return (1);
401}
402
403void
404ip6_input(struct mbuf *m)
405{
406	struct ip6_hdr *ip6;
407	int off = sizeof(struct ip6_hdr), nest;
408	u_int32_t plen;
409	u_int32_t rtalert = ~0;
410	int nxt, ours = 0;
411	struct ifnet *deliverifp = NULL, *ifp = NULL;
412	struct in6_addr odst;
413	struct route_in6 rin6;
414	int srcrt = 0;
415	struct llentry *lle = NULL;
416	struct sockaddr_in6 dst6, *dst;
417
418	bzero(&rin6, sizeof(struct route_in6));
419#ifdef IPSEC
420	/*
421	 * should the inner packet be considered authentic?
422	 * see comment in ah4_input().
423	 * NB: m cannot be NULL when passed to the input routine
424	 */
425
426	m->m_flags &= ~M_AUTHIPHDR;
427	m->m_flags &= ~M_AUTHIPDGM;
428
429#endif /* IPSEC */
430
431	/*
432	 * make sure we don't have onion peering information into m_tag.
433	 */
434	ip6_delaux(m);
435
436	if (m->m_flags & M_FASTFWD_OURS) {
437		/*
438		 * Firewall changed destination to local.
439		 */
440		m->m_flags &= ~M_FASTFWD_OURS;
441		ours = 1;
442		deliverifp = m->m_pkthdr.rcvif;
443		ip6 = mtod(m, struct ip6_hdr *);
444		goto hbhcheck;
445	}
446
447	/*
448	 * mbuf statistics
449	 */
450	if (m->m_flags & M_EXT) {
451		if (m->m_next)
452			IP6STAT_INC(ip6s_mext2m);
453		else
454			IP6STAT_INC(ip6s_mext1);
455	} else {
456		if (m->m_next) {
457			if (m->m_flags & M_LOOP) {
458				IP6STAT_INC(ip6s_m2m[V_loif->if_index]);
459			} else if (m->m_pkthdr.rcvif->if_index < IP6S_M2MMAX)
460				IP6STAT_INC(
461				    ip6s_m2m[m->m_pkthdr.rcvif->if_index]);
462			else
463				IP6STAT_INC(ip6s_m2m[0]);
464		} else
465			IP6STAT_INC(ip6s_m1);
466	}
467
468	/* drop the packet if IPv6 operation is disabled on the IF */
469	if ((ND_IFINFO(m->m_pkthdr.rcvif)->flags & ND6_IFF_IFDISABLED)) {
470		m_freem(m);
471		return;
472	}
473
474	in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_receive);
475	IP6STAT_INC(ip6s_total);
476
477#ifndef PULLDOWN_TEST
478	/*
479	 * L2 bridge code and some other code can return mbuf chain
480	 * that does not conform to KAME requirement.  too bad.
481	 * XXX: fails to join if interface MTU > MCLBYTES.  jumbogram?
482	 */
483	if (m && m->m_next != NULL && m->m_pkthdr.len < MCLBYTES) {
484		struct mbuf *n;
485
486		if (m->m_pkthdr.len > MHLEN)
487			n = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
488		else
489			n = m_gethdr(M_NOWAIT, MT_DATA);
490		if (n == NULL) {
491			m_freem(m);
492			return;	/* ENOBUFS */
493		}
494
495		m_move_pkthdr(n, m);
496		m_copydata(m, 0, n->m_pkthdr.len, mtod(n, caddr_t));
497		n->m_len = n->m_pkthdr.len;
498		m_freem(m);
499		m = n;
500	}
501	IP6_EXTHDR_CHECK(m, 0, sizeof(struct ip6_hdr), /* nothing */);
502#endif
503
504	if (m->m_len < sizeof(struct ip6_hdr)) {
505		struct ifnet *inifp;
506		inifp = m->m_pkthdr.rcvif;
507		if ((m = m_pullup(m, sizeof(struct ip6_hdr))) == NULL) {
508			IP6STAT_INC(ip6s_toosmall);
509			in6_ifstat_inc(inifp, ifs6_in_hdrerr);
510			return;
511		}
512	}
513
514	ip6 = mtod(m, struct ip6_hdr *);
515
516	if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) {
517		IP6STAT_INC(ip6s_badvers);
518		in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_hdrerr);
519		goto bad;
520	}
521
522	IP6STAT_INC(ip6s_nxthist[ip6->ip6_nxt]);
523
524	IP_PROBE(receive, NULL, NULL, ip6, m->m_pkthdr.rcvif, NULL, ip6);
525
526	/*
527	 * Check against address spoofing/corruption.
528	 */
529	if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_src) ||
530	    IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_dst)) {
531		/*
532		 * XXX: "badscope" is not very suitable for a multicast source.
533		 */
534		IP6STAT_INC(ip6s_badscope);
535		in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
536		goto bad;
537	}
538	if (IN6_IS_ADDR_MC_INTFACELOCAL(&ip6->ip6_dst) &&
539	    !(m->m_flags & M_LOOP)) {
540		/*
541		 * In this case, the packet should come from the loopback
542		 * interface.  However, we cannot just check the if_flags,
543		 * because ip6_mloopback() passes the "actual" interface
544		 * as the outgoing/incoming interface.
545		 */
546		IP6STAT_INC(ip6s_badscope);
547		in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
548		goto bad;
549	}
550	if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) &&
551	    IPV6_ADDR_MC_SCOPE(&ip6->ip6_dst) == 0) {
552		/*
553		 * RFC4291 2.7:
554		 * Nodes must not originate a packet to a multicast address
555		 * whose scop field contains the reserved value 0; if such
556		 * a packet is received, it must be silently dropped.
557		 */
558		IP6STAT_INC(ip6s_badscope);
559		in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
560		goto bad;
561	}
562#ifdef ALTQ
563	if (altq_input != NULL && (*altq_input)(m, AF_INET6) == 0) {
564		/* packet is dropped by traffic conditioner */
565		return;
566	}
567#endif
568	/*
569	 * The following check is not documented in specs.  A malicious
570	 * party may be able to use IPv4 mapped addr to confuse tcp/udp stack
571	 * and bypass security checks (act as if it was from 127.0.0.1 by using
572	 * IPv6 src ::ffff:127.0.0.1).  Be cautious.
573	 *
574	 * This check chokes if we are in an SIIT cloud.  As none of BSDs
575	 * support IPv4-less kernel compilation, we cannot support SIIT
576	 * environment at all.  So, it makes more sense for us to reject any
577	 * malicious packets for non-SIIT environment, than try to do a
578	 * partial support for SIIT environment.
579	 */
580	if (IN6_IS_ADDR_V4MAPPED(&ip6->ip6_src) ||
581	    IN6_IS_ADDR_V4MAPPED(&ip6->ip6_dst)) {
582		IP6STAT_INC(ip6s_badscope);
583		in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
584		goto bad;
585	}
586#if 0
587	/*
588	 * Reject packets with IPv4 compatible addresses (auto tunnel).
589	 *
590	 * The code forbids auto tunnel relay case in RFC1933 (the check is
591	 * stronger than RFC1933).  We may want to re-enable it if mech-xx
592	 * is revised to forbid relaying case.
593	 */
594	if (IN6_IS_ADDR_V4COMPAT(&ip6->ip6_src) ||
595	    IN6_IS_ADDR_V4COMPAT(&ip6->ip6_dst)) {
596		IP6STAT_INC(ip6s_badscope);
597		in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
598		goto bad;
599	}
600#endif
601#ifdef IPSEC
602	/*
603	 * Bypass packet filtering for packets previously handled by IPsec.
604	 */
605	if (ip6_ipsec_filtertunnel(m))
606		goto passin;
607#endif /* IPSEC */
608
609	/*
610	 * Run through list of hooks for input packets.
611	 *
612	 * NB: Beware of the destination address changing
613	 *     (e.g. by NAT rewriting).  When this happens,
614	 *     tell ip6_forward to do the right thing.
615	 */
616	odst = ip6->ip6_dst;
617
618	/* Jump over all PFIL processing if hooks are not active. */
619	if (!PFIL_HOOKED(&V_inet6_pfil_hook))
620		goto passin;
621
622	if (pfil_run_hooks(&V_inet6_pfil_hook, &m,
623	    m->m_pkthdr.rcvif, PFIL_IN, NULL))
624		return;
625	if (m == NULL)			/* consumed by filter */
626		return;
627	ip6 = mtod(m, struct ip6_hdr *);
628	srcrt = !IN6_ARE_ADDR_EQUAL(&odst, &ip6->ip6_dst);
629
630	if (m->m_flags & M_FASTFWD_OURS) {
631		m->m_flags &= ~M_FASTFWD_OURS;
632		ours = 1;
633		deliverifp = m->m_pkthdr.rcvif;
634		goto hbhcheck;
635	}
636	if ((m->m_flags & M_IP6_NEXTHOP) &&
637	    m_tag_find(m, PACKET_TAG_IPFORWARD, NULL) != NULL) {
638		/*
639		 * Directly ship the packet on.  This allows forwarding
640		 * packets originally destined to us to some other directly
641		 * connected host.
642		 */
643		ip6_forward(m, 1);
644		goto out;
645	}
646
647passin:
648	/*
649	 * Disambiguate address scope zones (if there is ambiguity).
650	 * We first make sure that the original source or destination address
651	 * is not in our internal form for scoped addresses.  Such addresses
652	 * are not necessarily invalid spec-wise, but we cannot accept them due
653	 * to the usage conflict.
654	 * in6_setscope() then also checks and rejects the cases where src or
655	 * dst are the loopback address and the receiving interface
656	 * is not loopback.
657	 */
658	if (in6_clearscope(&ip6->ip6_src) || in6_clearscope(&ip6->ip6_dst)) {
659		IP6STAT_INC(ip6s_badscope); /* XXX */
660		goto bad;
661	}
662	if (in6_setscope(&ip6->ip6_src, m->m_pkthdr.rcvif, NULL) ||
663	    in6_setscope(&ip6->ip6_dst, m->m_pkthdr.rcvif, NULL)) {
664		IP6STAT_INC(ip6s_badscope);
665		goto bad;
666	}
667
668	/*
669	 * Multicast check. Assume packet is for us to avoid
670	 * prematurely taking locks.
671	 */
672	if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
673		ours = 1;
674		in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_mcast);
675		deliverifp = m->m_pkthdr.rcvif;
676		goto hbhcheck;
677	}
678
679	/*
680	 *  Unicast check
681	 */
682
683	bzero(&dst6, sizeof(dst6));
684	dst6.sin6_family = AF_INET6;
685	dst6.sin6_len = sizeof(struct sockaddr_in6);
686	dst6.sin6_addr = ip6->ip6_dst;
687	ifp = m->m_pkthdr.rcvif;
688	IF_AFDATA_RLOCK(ifp);
689	lle = lla_lookup(LLTABLE6(ifp), 0,
690	     (struct sockaddr *)&dst6);
691	IF_AFDATA_RUNLOCK(ifp);
692	if ((lle != NULL) && (lle->la_flags & LLE_IFADDR)) {
693		struct ifaddr *ifa;
694		struct in6_ifaddr *ia6;
695		int bad;
696
697		bad = 1;
698#define	sa_equal(a1, a2)						\
699	(bcmp((a1), (a2), ((a1))->sin6_len) == 0)
700		IF_ADDR_RLOCK(ifp);
701		TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
702			if (ifa->ifa_addr->sa_family != dst6.sin6_family)
703				continue;
704			if (sa_equal(&dst6, ifa->ifa_addr))
705				break;
706		}
707		KASSERT(ifa != NULL, ("%s: ifa not found for lle %p",
708		    __func__, lle));
709#undef sa_equal
710
711		ia6 = (struct in6_ifaddr *)ifa;
712		if (!(ia6->ia6_flags & IN6_IFF_NOTREADY)) {
713			/* Count the packet in the ip address stats */
714			ia6->ia_ifa.if_ipackets++;
715			ia6->ia_ifa.if_ibytes += m->m_pkthdr.len;
716
717			/*
718			 * record address information into m_tag.
719			 */
720			(void)ip6_setdstifaddr(m, ia6);
721
722			bad = 0;
723		} else {
724			char ip6bufs[INET6_ADDRSTRLEN];
725			char ip6bufd[INET6_ADDRSTRLEN];
726			/* address is not ready, so discard the packet. */
727			nd6log((LOG_INFO,
728			    "ip6_input: packet to an unready address %s->%s\n",
729			    ip6_sprintf(ip6bufs, &ip6->ip6_src),
730			    ip6_sprintf(ip6bufd, &ip6->ip6_dst)));
731		}
732		IF_ADDR_RUNLOCK(ifp);
733		LLE_RUNLOCK(lle);
734		if (bad)
735			goto bad;
736		else {
737			ours = 1;
738			deliverifp = ifp;
739			goto hbhcheck;
740		}
741	}
742	if (lle != NULL)
743		LLE_RUNLOCK(lle);
744
745	dst = &rin6.ro_dst;
746	dst->sin6_len = sizeof(struct sockaddr_in6);
747	dst->sin6_family = AF_INET6;
748	dst->sin6_addr = ip6->ip6_dst;
749	rin6.ro_rt = in6_rtalloc1((struct sockaddr *)dst, 0, 0, M_GETFIB(m));
750	if (rin6.ro_rt)
751		RT_UNLOCK(rin6.ro_rt);
752
753#define rt6_key(r) ((struct sockaddr_in6 *)((r)->rt_nodes->rn_key))
754
755	/*
756	 * Accept the packet if the forwarding interface to the destination
757	 * according to the routing table is the loopback interface,
758	 * unless the associated route has a gateway.
759	 * Note that this approach causes to accept a packet if there is a
760	 * route to the loopback interface for the destination of the packet.
761	 * But we think it's even useful in some situations, e.g. when using
762	 * a special daemon which wants to intercept the packet.
763	 *
764	 * XXX: some OSes automatically make a cloned route for the destination
765	 * of an outgoing packet.  If the outgoing interface of the packet
766	 * is a loopback one, the kernel would consider the packet to be
767	 * accepted, even if we have no such address assinged on the interface.
768	 * We check the cloned flag of the route entry to reject such cases,
769	 * assuming that route entries for our own addresses are not made by
770	 * cloning (it should be true because in6_addloop explicitly installs
771	 * the host route).  However, we might have to do an explicit check
772	 * while it would be less efficient.  Or, should we rather install a
773	 * reject route for such a case?
774	 */
775	if (rin6.ro_rt &&
776	    (rin6.ro_rt->rt_flags &
777	     (RTF_HOST|RTF_GATEWAY)) == RTF_HOST &&
778#ifdef RTF_WASCLONED
779	    !(rin6.ro_rt->rt_flags & RTF_WASCLONED) &&
780#endif
781#ifdef RTF_CLONED
782	    !(rin6.ro_rt->rt_flags & RTF_CLONED) &&
783#endif
784#if 0
785	    /*
786	     * The check below is redundant since the comparison of
787	     * the destination and the key of the rtentry has
788	     * already done through looking up the routing table.
789	     */
790	    IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst,
791	    &rt6_key(rin6.ro_rt)->sin6_addr)
792#endif
793	    rin6.ro_rt->rt_ifp->if_type == IFT_LOOP) {
794		int free_ia6 = 0;
795		struct in6_ifaddr *ia6;
796
797		/*
798		 * found the loopback route to the interface address
799		 */
800		if (rin6.ro_rt->rt_gateway->sa_family == AF_LINK) {
801			struct sockaddr_in6 dest6;
802
803			bzero(&dest6, sizeof(dest6));
804			dest6.sin6_family = AF_INET6;
805			dest6.sin6_len = sizeof(dest6);
806			dest6.sin6_addr = ip6->ip6_dst;
807			ia6 = (struct in6_ifaddr *)
808			    ifa_ifwithaddr((struct sockaddr *)&dest6);
809			if (ia6 == NULL)
810				goto bad;
811			free_ia6 = 1;
812		}
813		else
814			ia6 = (struct in6_ifaddr *)rin6.ro_rt->rt_ifa;
815
816		/*
817		 * record address information into m_tag.
818		 */
819		(void)ip6_setdstifaddr(m, ia6);
820
821		/*
822		 * packets to a tentative, duplicated, or somehow invalid
823		 * address must not be accepted.
824		 */
825		if (!(ia6->ia6_flags & IN6_IFF_NOTREADY)) {
826			/* this address is ready */
827			ours = 1;
828			deliverifp = ia6->ia_ifp;	/* correct? */
829			/* Count the packet in the ip address stats */
830			ia6->ia_ifa.if_ipackets++;
831			ia6->ia_ifa.if_ibytes += m->m_pkthdr.len;
832			if (ia6 != NULL && free_ia6 != 0)
833				ifa_free(&ia6->ia_ifa);
834			goto hbhcheck;
835		} else {
836			char ip6bufs[INET6_ADDRSTRLEN];
837			char ip6bufd[INET6_ADDRSTRLEN];
838			/* address is not ready, so discard the packet. */
839			nd6log((LOG_INFO,
840			    "ip6_input: packet to an unready address %s->%s\n",
841			    ip6_sprintf(ip6bufs, &ip6->ip6_src),
842			    ip6_sprintf(ip6bufd, &ip6->ip6_dst)));
843
844			if (ia6 != NULL && free_ia6 != 0)
845				ifa_free(&ia6->ia_ifa);
846			goto bad;
847		}
848	}
849
850	/*
851	 * FAITH (Firewall Aided Internet Translator)
852	 */
853	if (V_ip6_keepfaith) {
854		if (rin6.ro_rt && rin6.ro_rt->rt_ifp &&
855		    rin6.ro_rt->rt_ifp->if_type == IFT_FAITH) {
856			/* XXX do we need more sanity checks? */
857			ours = 1;
858			deliverifp = rin6.ro_rt->rt_ifp; /* faith */
859			goto hbhcheck;
860		}
861	}
862
863	/*
864	 * Now there is no reason to process the packet if it's not our own
865	 * and we're not a router.
866	 */
867	if (!V_ip6_forwarding) {
868		IP6STAT_INC(ip6s_cantforward);
869		in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
870		goto bad;
871	}
872
873  hbhcheck:
874	/*
875	 * record address information into m_tag, if we don't have one yet.
876	 * note that we are unable to record it, if the address is not listed
877	 * as our interface address (e.g. multicast addresses, addresses
878	 * within FAITH prefixes and such).
879	 */
880	if (deliverifp) {
881		struct in6_ifaddr *ia6;
882
883 		if ((ia6 = ip6_getdstifaddr(m)) != NULL) {
884			ifa_free(&ia6->ia_ifa);
885		} else {
886			ia6 = in6_ifawithifp(deliverifp, &ip6->ip6_dst);
887			if (ia6) {
888				if (!ip6_setdstifaddr(m, ia6)) {
889					/*
890					 * XXX maybe we should drop the packet here,
891					 * as we could not provide enough information
892					 * to the upper layers.
893					 */
894				}
895				ifa_free(&ia6->ia_ifa);
896			}
897		}
898	}
899
900	/*
901	 * Process Hop-by-Hop options header if it's contained.
902	 * m may be modified in ip6_hopopts_input().
903	 * If a JumboPayload option is included, plen will also be modified.
904	 */
905	plen = (u_int32_t)ntohs(ip6->ip6_plen);
906	if (ip6->ip6_nxt == IPPROTO_HOPOPTS) {
907		int error;
908
909		error = ip6_input_hbh(m, &plen, &rtalert, &off, &nxt, &ours);
910		if (error != 0)
911			goto out;
912	} else
913		nxt = ip6->ip6_nxt;
914
915	/*
916	 * Check that the amount of data in the buffers
917	 * is as at least much as the IPv6 header would have us expect.
918	 * Trim mbufs if longer than we expect.
919	 * Drop packet if shorter than we expect.
920	 */
921	if (m->m_pkthdr.len - sizeof(struct ip6_hdr) < plen) {
922		IP6STAT_INC(ip6s_tooshort);
923		in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_truncated);
924		goto bad;
925	}
926	if (m->m_pkthdr.len > sizeof(struct ip6_hdr) + plen) {
927		if (m->m_len == m->m_pkthdr.len) {
928			m->m_len = sizeof(struct ip6_hdr) + plen;
929			m->m_pkthdr.len = sizeof(struct ip6_hdr) + plen;
930		} else
931			m_adj(m, sizeof(struct ip6_hdr) + plen - m->m_pkthdr.len);
932	}
933
934	/*
935	 * Forward if desirable.
936	 */
937	if (V_ip6_mrouter &&
938	    IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
939		/*
940		 * If we are acting as a multicast router, all
941		 * incoming multicast packets are passed to the
942		 * kernel-level multicast forwarding function.
943		 * The packet is returned (relatively) intact; if
944		 * ip6_mforward() returns a non-zero value, the packet
945		 * must be discarded, else it may be accepted below.
946		 *
947		 * XXX TODO: Check hlim and multicast scope here to avoid
948		 * unnecessarily calling into ip6_mforward().
949		 */
950		if (ip6_mforward &&
951		    ip6_mforward(ip6, m->m_pkthdr.rcvif, m)) {
952			IP6STAT_INC(ip6s_cantforward);
953			in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
954			goto bad;
955		}
956	} else if (!ours) {
957		ip6_forward(m, srcrt);
958		goto out;
959	}
960
961	ip6 = mtod(m, struct ip6_hdr *);
962
963	/*
964	 * Malicious party may be able to use IPv4 mapped addr to confuse
965	 * tcp/udp stack and bypass security checks (act as if it was from
966	 * 127.0.0.1 by using IPv6 src ::ffff:127.0.0.1).  Be cautious.
967	 *
968	 * For SIIT end node behavior, you may want to disable the check.
969	 * However, you will  become vulnerable to attacks using IPv4 mapped
970	 * source.
971	 */
972	if (IN6_IS_ADDR_V4MAPPED(&ip6->ip6_src) ||
973	    IN6_IS_ADDR_V4MAPPED(&ip6->ip6_dst)) {
974		IP6STAT_INC(ip6s_badscope);
975		in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
976		goto bad;
977	}
978
979	/*
980	 * Tell launch routine the next header
981	 */
982	IP6STAT_INC(ip6s_delivered);
983	in6_ifstat_inc(deliverifp, ifs6_in_deliver);
984	nest = 0;
985
986	while (nxt != IPPROTO_DONE) {
987		if (V_ip6_hdrnestlimit && (++nest > V_ip6_hdrnestlimit)) {
988			IP6STAT_INC(ip6s_toomanyhdr);
989			goto bad;
990		}
991
992		/*
993		 * protection against faulty packet - there should be
994		 * more sanity checks in header chain processing.
995		 */
996		if (m->m_pkthdr.len < off) {
997			IP6STAT_INC(ip6s_tooshort);
998			in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_truncated);
999			goto bad;
1000		}
1001
1002#ifdef IPSEC
1003		/*
1004		 * enforce IPsec policy checking if we are seeing last header.
1005		 * note that we do not visit this with protocols with pcb layer
1006		 * code - like udp/tcp/raw ip.
1007		 */
1008		if (ip6_ipsec_input(m, nxt))
1009			goto bad;
1010#endif /* IPSEC */
1011
1012		/*
1013		 * Use mbuf flags to propagate Router Alert option to
1014		 * ICMPv6 layer, as hop-by-hop options have been stripped.
1015		 */
1016		if (nxt == IPPROTO_ICMPV6 && rtalert != ~0)
1017			m->m_flags |= M_RTALERT_MLD;
1018
1019		nxt = (*inet6sw[ip6_protox[nxt]].pr_input)(&m, &off, nxt);
1020	}
1021	goto out;
1022bad:
1023	m_freem(m);
1024out:
1025	if (rin6.ro_rt)
1026		RTFREE(rin6.ro_rt);
1027}
1028
1029/*
1030 * set/grab in6_ifaddr correspond to IPv6 destination address.
1031 * XXX backward compatibility wrapper
1032 *
1033 * XXXRW: We should bump the refcount on ia6 before sticking it in the m_tag,
1034 * and then bump it when the tag is copied, and release it when the tag is
1035 * freed.  Unfortunately, m_tags don't support deep copies (yet), so instead
1036 * we just bump the ia refcount when we receive it.  This should be fixed.
1037 */
1038static struct ip6aux *
1039ip6_setdstifaddr(struct mbuf *m, struct in6_ifaddr *ia6)
1040{
1041	struct ip6aux *ip6a;
1042
1043	ip6a = ip6_addaux(m);
1044	if (ip6a)
1045		ip6a->ip6a_dstia6 = ia6;
1046	return ip6a;	/* NULL if failed to set */
1047}
1048
1049struct in6_ifaddr *
1050ip6_getdstifaddr(struct mbuf *m)
1051{
1052	struct ip6aux *ip6a;
1053	struct in6_ifaddr *ia;
1054
1055	ip6a = ip6_findaux(m);
1056	if (ip6a) {
1057		ia = ip6a->ip6a_dstia6;
1058		ifa_ref(&ia->ia_ifa);
1059		return ia;
1060	} else
1061		return NULL;
1062}
1063
1064/*
1065 * Hop-by-Hop options header processing. If a valid jumbo payload option is
1066 * included, the real payload length will be stored in plenp.
1067 *
1068 * rtalertp - XXX: should be stored more smart way
1069 */
1070static int
1071ip6_hopopts_input(u_int32_t *plenp, u_int32_t *rtalertp,
1072    struct mbuf **mp, int *offp)
1073{
1074	struct mbuf *m = *mp;
1075	int off = *offp, hbhlen;
1076	struct ip6_hbh *hbh;
1077
1078	/* validation of the length of the header */
1079#ifndef PULLDOWN_TEST
1080	IP6_EXTHDR_CHECK(m, off, sizeof(*hbh), -1);
1081	hbh = (struct ip6_hbh *)(mtod(m, caddr_t) + off);
1082	hbhlen = (hbh->ip6h_len + 1) << 3;
1083
1084	IP6_EXTHDR_CHECK(m, off, hbhlen, -1);
1085	hbh = (struct ip6_hbh *)(mtod(m, caddr_t) + off);
1086#else
1087	IP6_EXTHDR_GET(hbh, struct ip6_hbh *, m,
1088		sizeof(struct ip6_hdr), sizeof(struct ip6_hbh));
1089	if (hbh == NULL) {
1090		IP6STAT_INC(ip6s_tooshort);
1091		return -1;
1092	}
1093	hbhlen = (hbh->ip6h_len + 1) << 3;
1094	IP6_EXTHDR_GET(hbh, struct ip6_hbh *, m, sizeof(struct ip6_hdr),
1095		hbhlen);
1096	if (hbh == NULL) {
1097		IP6STAT_INC(ip6s_tooshort);
1098		return -1;
1099	}
1100#endif
1101	off += hbhlen;
1102	hbhlen -= sizeof(struct ip6_hbh);
1103	if (ip6_process_hopopts(m, (u_int8_t *)hbh + sizeof(struct ip6_hbh),
1104				hbhlen, rtalertp, plenp) < 0)
1105		return (-1);
1106
1107	*offp = off;
1108	*mp = m;
1109	return (0);
1110}
1111
1112/*
1113 * Search header for all Hop-by-hop options and process each option.
1114 * This function is separate from ip6_hopopts_input() in order to
1115 * handle a case where the sending node itself process its hop-by-hop
1116 * options header. In such a case, the function is called from ip6_output().
1117 *
1118 * The function assumes that hbh header is located right after the IPv6 header
1119 * (RFC2460 p7), opthead is pointer into data content in m, and opthead to
1120 * opthead + hbhlen is located in contiguous memory region.
1121 */
1122int
1123ip6_process_hopopts(struct mbuf *m, u_int8_t *opthead, int hbhlen,
1124    u_int32_t *rtalertp, u_int32_t *plenp)
1125{
1126	struct ip6_hdr *ip6;
1127	int optlen = 0;
1128	u_int8_t *opt = opthead;
1129	u_int16_t rtalert_val;
1130	u_int32_t jumboplen;
1131	const int erroff = sizeof(struct ip6_hdr) + sizeof(struct ip6_hbh);
1132
1133	for (; hbhlen > 0; hbhlen -= optlen, opt += optlen) {
1134		switch (*opt) {
1135		case IP6OPT_PAD1:
1136			optlen = 1;
1137			break;
1138		case IP6OPT_PADN:
1139			if (hbhlen < IP6OPT_MINLEN) {
1140				IP6STAT_INC(ip6s_toosmall);
1141				goto bad;
1142			}
1143			optlen = *(opt + 1) + 2;
1144			break;
1145		case IP6OPT_ROUTER_ALERT:
1146			/* XXX may need check for alignment */
1147			if (hbhlen < IP6OPT_RTALERT_LEN) {
1148				IP6STAT_INC(ip6s_toosmall);
1149				goto bad;
1150			}
1151			if (*(opt + 1) != IP6OPT_RTALERT_LEN - 2) {
1152				/* XXX stat */
1153				icmp6_error(m, ICMP6_PARAM_PROB,
1154				    ICMP6_PARAMPROB_HEADER,
1155				    erroff + opt + 1 - opthead);
1156				return (-1);
1157			}
1158			optlen = IP6OPT_RTALERT_LEN;
1159			bcopy((caddr_t)(opt + 2), (caddr_t)&rtalert_val, 2);
1160			*rtalertp = ntohs(rtalert_val);
1161			break;
1162		case IP6OPT_JUMBO:
1163			/* XXX may need check for alignment */
1164			if (hbhlen < IP6OPT_JUMBO_LEN) {
1165				IP6STAT_INC(ip6s_toosmall);
1166				goto bad;
1167			}
1168			if (*(opt + 1) != IP6OPT_JUMBO_LEN - 2) {
1169				/* XXX stat */
1170				icmp6_error(m, ICMP6_PARAM_PROB,
1171				    ICMP6_PARAMPROB_HEADER,
1172				    erroff + opt + 1 - opthead);
1173				return (-1);
1174			}
1175			optlen = IP6OPT_JUMBO_LEN;
1176
1177			/*
1178			 * IPv6 packets that have non 0 payload length
1179			 * must not contain a jumbo payload option.
1180			 */
1181			ip6 = mtod(m, struct ip6_hdr *);
1182			if (ip6->ip6_plen) {
1183				IP6STAT_INC(ip6s_badoptions);
1184				icmp6_error(m, ICMP6_PARAM_PROB,
1185				    ICMP6_PARAMPROB_HEADER,
1186				    erroff + opt - opthead);
1187				return (-1);
1188			}
1189
1190			/*
1191			 * We may see jumbolen in unaligned location, so
1192			 * we'd need to perform bcopy().
1193			 */
1194			bcopy(opt + 2, &jumboplen, sizeof(jumboplen));
1195			jumboplen = (u_int32_t)htonl(jumboplen);
1196
1197#if 1
1198			/*
1199			 * if there are multiple jumbo payload options,
1200			 * *plenp will be non-zero and the packet will be
1201			 * rejected.
1202			 * the behavior may need some debate in ipngwg -
1203			 * multiple options does not make sense, however,
1204			 * there's no explicit mention in specification.
1205			 */
1206			if (*plenp != 0) {
1207				IP6STAT_INC(ip6s_badoptions);
1208				icmp6_error(m, ICMP6_PARAM_PROB,
1209				    ICMP6_PARAMPROB_HEADER,
1210				    erroff + opt + 2 - opthead);
1211				return (-1);
1212			}
1213#endif
1214
1215			/*
1216			 * jumbo payload length must be larger than 65535.
1217			 */
1218			if (jumboplen <= IPV6_MAXPACKET) {
1219				IP6STAT_INC(ip6s_badoptions);
1220				icmp6_error(m, ICMP6_PARAM_PROB,
1221				    ICMP6_PARAMPROB_HEADER,
1222				    erroff + opt + 2 - opthead);
1223				return (-1);
1224			}
1225			*plenp = jumboplen;
1226
1227			break;
1228		default:		/* unknown option */
1229			if (hbhlen < IP6OPT_MINLEN) {
1230				IP6STAT_INC(ip6s_toosmall);
1231				goto bad;
1232			}
1233			optlen = ip6_unknown_opt(opt, m,
1234			    erroff + opt - opthead);
1235			if (optlen == -1)
1236				return (-1);
1237			optlen += 2;
1238			break;
1239		}
1240	}
1241
1242	return (0);
1243
1244  bad:
1245	m_freem(m);
1246	return (-1);
1247}
1248
1249/*
1250 * Unknown option processing.
1251 * The third argument `off' is the offset from the IPv6 header to the option,
1252 * which is necessary if the IPv6 header the and option header and IPv6 header
1253 * is not contiguous in order to return an ICMPv6 error.
1254 */
1255int
1256ip6_unknown_opt(u_int8_t *optp, struct mbuf *m, int off)
1257{
1258	struct ip6_hdr *ip6;
1259
1260	switch (IP6OPT_TYPE(*optp)) {
1261	case IP6OPT_TYPE_SKIP: /* ignore the option */
1262		return ((int)*(optp + 1));
1263	case IP6OPT_TYPE_DISCARD:	/* silently discard */
1264		m_freem(m);
1265		return (-1);
1266	case IP6OPT_TYPE_FORCEICMP: /* send ICMP even if multicasted */
1267		IP6STAT_INC(ip6s_badoptions);
1268		icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_OPTION, off);
1269		return (-1);
1270	case IP6OPT_TYPE_ICMP: /* send ICMP if not multicasted */
1271		IP6STAT_INC(ip6s_badoptions);
1272		ip6 = mtod(m, struct ip6_hdr *);
1273		if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) ||
1274		    (m->m_flags & (M_BCAST|M_MCAST)))
1275			m_freem(m);
1276		else
1277			icmp6_error(m, ICMP6_PARAM_PROB,
1278				    ICMP6_PARAMPROB_OPTION, off);
1279		return (-1);
1280	}
1281
1282	m_freem(m);		/* XXX: NOTREACHED */
1283	return (-1);
1284}
1285
1286/*
1287 * Create the "control" list for this pcb.
1288 * These functions will not modify mbuf chain at all.
1289 *
1290 * With KAME mbuf chain restriction:
1291 * The routine will be called from upper layer handlers like tcp6_input().
1292 * Thus the routine assumes that the caller (tcp6_input) have already
1293 * called IP6_EXTHDR_CHECK() and all the extension headers are located in the
1294 * very first mbuf on the mbuf chain.
1295 *
1296 * ip6_savecontrol_v4 will handle those options that are possible to be
1297 * set on a v4-mapped socket.
1298 * ip6_savecontrol will directly call ip6_savecontrol_v4 to handle those
1299 * options and handle the v6-only ones itself.
1300 */
1301struct mbuf **
1302ip6_savecontrol_v4(struct inpcb *inp, struct mbuf *m, struct mbuf **mp,
1303    int *v4only)
1304{
1305	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
1306
1307#ifdef SO_TIMESTAMP
1308	if ((inp->inp_socket->so_options & SO_TIMESTAMP) != 0) {
1309		struct timeval tv;
1310
1311		microtime(&tv);
1312		*mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv),
1313		    SCM_TIMESTAMP, SOL_SOCKET);
1314		if (*mp)
1315			mp = &(*mp)->m_next;
1316	}
1317#endif
1318
1319#define IS2292(inp, x, y)	(((inp)->inp_flags & IN6P_RFC2292) ? (x) : (y))
1320	/* RFC 2292 sec. 5 */
1321	if ((inp->inp_flags & IN6P_PKTINFO) != 0) {
1322		struct in6_pktinfo pi6;
1323
1324		if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) {
1325#ifdef INET
1326			struct ip *ip;
1327
1328			ip = mtod(m, struct ip *);
1329			pi6.ipi6_addr.s6_addr32[0] = 0;
1330			pi6.ipi6_addr.s6_addr32[1] = 0;
1331			pi6.ipi6_addr.s6_addr32[2] = IPV6_ADDR_INT32_SMP;
1332			pi6.ipi6_addr.s6_addr32[3] = ip->ip_dst.s_addr;
1333#else
1334			/* We won't hit this code */
1335			bzero(&pi6.ipi6_addr, sizeof(struct in6_addr));
1336#endif
1337		} else {
1338			bcopy(&ip6->ip6_dst, &pi6.ipi6_addr, sizeof(struct in6_addr));
1339			in6_clearscope(&pi6.ipi6_addr);	/* XXX */
1340		}
1341		pi6.ipi6_ifindex =
1342		    (m && m->m_pkthdr.rcvif) ? m->m_pkthdr.rcvif->if_index : 0;
1343
1344		*mp = sbcreatecontrol((caddr_t) &pi6,
1345		    sizeof(struct in6_pktinfo),
1346		    IS2292(inp, IPV6_2292PKTINFO, IPV6_PKTINFO), IPPROTO_IPV6);
1347		if (*mp)
1348			mp = &(*mp)->m_next;
1349	}
1350
1351	if ((inp->inp_flags & IN6P_HOPLIMIT) != 0) {
1352		int hlim;
1353
1354		if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) {
1355#ifdef INET
1356			struct ip *ip;
1357
1358			ip = mtod(m, struct ip *);
1359			hlim = ip->ip_ttl;
1360#else
1361			/* We won't hit this code */
1362			hlim = 0;
1363#endif
1364		} else {
1365			hlim = ip6->ip6_hlim & 0xff;
1366		}
1367		*mp = sbcreatecontrol((caddr_t) &hlim, sizeof(int),
1368		    IS2292(inp, IPV6_2292HOPLIMIT, IPV6_HOPLIMIT),
1369		    IPPROTO_IPV6);
1370		if (*mp)
1371			mp = &(*mp)->m_next;
1372	}
1373
1374	if ((inp->inp_flags & IN6P_TCLASS) != 0) {
1375		int tclass;
1376
1377		if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) {
1378#ifdef INET
1379			struct ip *ip;
1380
1381			ip = mtod(m, struct ip *);
1382			tclass = ip->ip_tos;
1383#else
1384			/* We won't hit this code */
1385			tclass = 0;
1386#endif
1387		} else {
1388			u_int32_t flowinfo;
1389
1390			flowinfo = (u_int32_t)ntohl(ip6->ip6_flow & IPV6_FLOWINFO_MASK);
1391			flowinfo >>= 20;
1392			tclass = flowinfo & 0xff;
1393		}
1394		*mp = sbcreatecontrol((caddr_t) &tclass, sizeof(int),
1395		    IPV6_TCLASS, IPPROTO_IPV6);
1396		if (*mp)
1397			mp = &(*mp)->m_next;
1398	}
1399
1400	if (v4only != NULL) {
1401		if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) {
1402			*v4only = 1;
1403		} else {
1404			*v4only = 0;
1405		}
1406	}
1407
1408	return (mp);
1409}
1410
1411void
1412ip6_savecontrol(struct inpcb *in6p, struct mbuf *m, struct mbuf **mp)
1413{
1414	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
1415	int v4only = 0;
1416
1417	mp = ip6_savecontrol_v4(in6p, m, mp, &v4only);
1418	if (v4only)
1419		return;
1420
1421	/*
1422	 * IPV6_HOPOPTS socket option.  Recall that we required super-user
1423	 * privilege for the option (see ip6_ctloutput), but it might be too
1424	 * strict, since there might be some hop-by-hop options which can be
1425	 * returned to normal user.
1426	 * See also RFC 2292 section 6 (or RFC 3542 section 8).
1427	 */
1428	if ((in6p->inp_flags & IN6P_HOPOPTS) != 0) {
1429		/*
1430		 * Check if a hop-by-hop options header is contatined in the
1431		 * received packet, and if so, store the options as ancillary
1432		 * data. Note that a hop-by-hop options header must be
1433		 * just after the IPv6 header, which is assured through the
1434		 * IPv6 input processing.
1435		 */
1436		if (ip6->ip6_nxt == IPPROTO_HOPOPTS) {
1437			struct ip6_hbh *hbh;
1438			int hbhlen = 0;
1439#ifdef PULLDOWN_TEST
1440			struct mbuf *ext;
1441#endif
1442
1443#ifndef PULLDOWN_TEST
1444			hbh = (struct ip6_hbh *)(ip6 + 1);
1445			hbhlen = (hbh->ip6h_len + 1) << 3;
1446#else
1447			ext = ip6_pullexthdr(m, sizeof(struct ip6_hdr),
1448			    ip6->ip6_nxt);
1449			if (ext == NULL) {
1450				IP6STAT_INC(ip6s_tooshort);
1451				return;
1452			}
1453			hbh = mtod(ext, struct ip6_hbh *);
1454			hbhlen = (hbh->ip6h_len + 1) << 3;
1455			if (hbhlen != ext->m_len) {
1456				m_freem(ext);
1457				IP6STAT_INC(ip6s_tooshort);
1458				return;
1459			}
1460#endif
1461
1462			/*
1463			 * XXX: We copy the whole header even if a
1464			 * jumbo payload option is included, the option which
1465			 * is to be removed before returning according to
1466			 * RFC2292.
1467			 * Note: this constraint is removed in RFC3542
1468			 */
1469			*mp = sbcreatecontrol((caddr_t)hbh, hbhlen,
1470			    IS2292(in6p, IPV6_2292HOPOPTS, IPV6_HOPOPTS),
1471			    IPPROTO_IPV6);
1472			if (*mp)
1473				mp = &(*mp)->m_next;
1474#ifdef PULLDOWN_TEST
1475			m_freem(ext);
1476#endif
1477		}
1478	}
1479
1480	if ((in6p->inp_flags & (IN6P_RTHDR | IN6P_DSTOPTS)) != 0) {
1481		int nxt = ip6->ip6_nxt, off = sizeof(struct ip6_hdr);
1482
1483		/*
1484		 * Search for destination options headers or routing
1485		 * header(s) through the header chain, and stores each
1486		 * header as ancillary data.
1487		 * Note that the order of the headers remains in
1488		 * the chain of ancillary data.
1489		 */
1490		while (1) {	/* is explicit loop prevention necessary? */
1491			struct ip6_ext *ip6e = NULL;
1492			int elen;
1493#ifdef PULLDOWN_TEST
1494			struct mbuf *ext = NULL;
1495#endif
1496
1497			/*
1498			 * if it is not an extension header, don't try to
1499			 * pull it from the chain.
1500			 */
1501			switch (nxt) {
1502			case IPPROTO_DSTOPTS:
1503			case IPPROTO_ROUTING:
1504			case IPPROTO_HOPOPTS:
1505			case IPPROTO_AH: /* is it possible? */
1506				break;
1507			default:
1508				goto loopend;
1509			}
1510
1511#ifndef PULLDOWN_TEST
1512			if (off + sizeof(*ip6e) > m->m_len)
1513				goto loopend;
1514			ip6e = (struct ip6_ext *)(mtod(m, caddr_t) + off);
1515			if (nxt == IPPROTO_AH)
1516				elen = (ip6e->ip6e_len + 2) << 2;
1517			else
1518				elen = (ip6e->ip6e_len + 1) << 3;
1519			if (off + elen > m->m_len)
1520				goto loopend;
1521#else
1522			ext = ip6_pullexthdr(m, off, nxt);
1523			if (ext == NULL) {
1524				IP6STAT_INC(ip6s_tooshort);
1525				return;
1526			}
1527			ip6e = mtod(ext, struct ip6_ext *);
1528			if (nxt == IPPROTO_AH)
1529				elen = (ip6e->ip6e_len + 2) << 2;
1530			else
1531				elen = (ip6e->ip6e_len + 1) << 3;
1532			if (elen != ext->m_len) {
1533				m_freem(ext);
1534				IP6STAT_INC(ip6s_tooshort);
1535				return;
1536			}
1537#endif
1538
1539			switch (nxt) {
1540			case IPPROTO_DSTOPTS:
1541				if (!(in6p->inp_flags & IN6P_DSTOPTS))
1542					break;
1543
1544				*mp = sbcreatecontrol((caddr_t)ip6e, elen,
1545				    IS2292(in6p,
1546					IPV6_2292DSTOPTS, IPV6_DSTOPTS),
1547				    IPPROTO_IPV6);
1548				if (*mp)
1549					mp = &(*mp)->m_next;
1550				break;
1551			case IPPROTO_ROUTING:
1552				if (!(in6p->inp_flags & IN6P_RTHDR))
1553					break;
1554
1555				*mp = sbcreatecontrol((caddr_t)ip6e, elen,
1556				    IS2292(in6p, IPV6_2292RTHDR, IPV6_RTHDR),
1557				    IPPROTO_IPV6);
1558				if (*mp)
1559					mp = &(*mp)->m_next;
1560				break;
1561			case IPPROTO_HOPOPTS:
1562			case IPPROTO_AH: /* is it possible? */
1563				break;
1564
1565			default:
1566				/*
1567				 * other cases have been filtered in the above.
1568				 * none will visit this case.  here we supply
1569				 * the code just in case (nxt overwritten or
1570				 * other cases).
1571				 */
1572#ifdef PULLDOWN_TEST
1573				m_freem(ext);
1574#endif
1575				goto loopend;
1576
1577			}
1578
1579			/* proceed with the next header. */
1580			off += elen;
1581			nxt = ip6e->ip6e_nxt;
1582			ip6e = NULL;
1583#ifdef PULLDOWN_TEST
1584			m_freem(ext);
1585			ext = NULL;
1586#endif
1587		}
1588	  loopend:
1589		;
1590	}
1591}
1592#undef IS2292
1593
1594void
1595ip6_notify_pmtu(struct inpcb *inp, struct sockaddr_in6 *dst, u_int32_t mtu)
1596{
1597	struct socket *so;
1598	struct mbuf *m_mtu;
1599	struct ip6_mtuinfo mtuctl;
1600
1601	KASSERT(inp != NULL, ("%s: inp == NULL", __func__));
1602	/*
1603	 * Notify the error by sending IPV6_PATHMTU ancillary data if
1604	 * application wanted to know the MTU value.
1605	 * NOTE: we notify disconnected sockets, because some udp
1606	 * applications keep sending sockets disconnected.
1607	 * NOTE: our implementation doesn't notify connected sockets that has
1608	 * foreign address that is different than given destination addresses
1609	 * (this is permitted by RFC 3542).
1610	 */
1611	if ((inp->inp_flags & IN6P_MTU) == 0 || (
1612	    !IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr) &&
1613	    !IN6_ARE_ADDR_EQUAL(&inp->in6p_faddr, &dst->sin6_addr)))
1614		return;
1615
1616	mtuctl.ip6m_mtu = mtu;
1617	mtuctl.ip6m_addr = *dst;
1618	if (sa6_recoverscope(&mtuctl.ip6m_addr))
1619		return;
1620
1621	if ((m_mtu = sbcreatecontrol((caddr_t)&mtuctl, sizeof(mtuctl),
1622	    IPV6_PATHMTU, IPPROTO_IPV6)) == NULL)
1623		return;
1624
1625	so =  inp->inp_socket;
1626	if (sbappendaddr(&so->so_rcv, (struct sockaddr *)dst, NULL, m_mtu)
1627	    == 0) {
1628		m_freem(m_mtu);
1629		/* XXX: should count statistics */
1630	} else
1631		sorwakeup(so);
1632}
1633
1634#ifdef PULLDOWN_TEST
1635/*
1636 * pull single extension header from mbuf chain.  returns single mbuf that
1637 * contains the result, or NULL on error.
1638 */
1639static struct mbuf *
1640ip6_pullexthdr(struct mbuf *m, size_t off, int nxt)
1641{
1642	struct ip6_ext ip6e;
1643	size_t elen;
1644	struct mbuf *n;
1645
1646#ifdef DIAGNOSTIC
1647	switch (nxt) {
1648	case IPPROTO_DSTOPTS:
1649	case IPPROTO_ROUTING:
1650	case IPPROTO_HOPOPTS:
1651	case IPPROTO_AH: /* is it possible? */
1652		break;
1653	default:
1654		printf("ip6_pullexthdr: invalid nxt=%d\n", nxt);
1655	}
1656#endif
1657
1658	m_copydata(m, off, sizeof(ip6e), (caddr_t)&ip6e);
1659	if (nxt == IPPROTO_AH)
1660		elen = (ip6e.ip6e_len + 2) << 2;
1661	else
1662		elen = (ip6e.ip6e_len + 1) << 3;
1663
1664	if (elen > MLEN)
1665		n = m_getcl(M_NOWAIT, MT_DATA, 0);
1666	else
1667		n = m_get(M_NOWAIT, MT_DATA);
1668	if (n == NULL)
1669		return NULL;
1670
1671	m_copydata(m, off, elen, mtod(n, caddr_t));
1672	n->m_len = elen;
1673	return n;
1674}
1675#endif
1676
1677/*
1678 * Get pointer to the previous header followed by the header
1679 * currently processed.
1680 * XXX: This function supposes that
1681 *	M includes all headers,
1682 *	the next header field and the header length field of each header
1683 *	are valid, and
1684 *	the sum of each header length equals to OFF.
1685 * Because of these assumptions, this function must be called very
1686 * carefully. Moreover, it will not be used in the near future when
1687 * we develop `neater' mechanism to process extension headers.
1688 */
1689char *
1690ip6_get_prevhdr(struct mbuf *m, int off)
1691{
1692	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
1693
1694	if (off == sizeof(struct ip6_hdr))
1695		return (&ip6->ip6_nxt);
1696	else {
1697		int len, nxt;
1698		struct ip6_ext *ip6e = NULL;
1699
1700		nxt = ip6->ip6_nxt;
1701		len = sizeof(struct ip6_hdr);
1702		while (len < off) {
1703			ip6e = (struct ip6_ext *)(mtod(m, caddr_t) + len);
1704
1705			switch (nxt) {
1706			case IPPROTO_FRAGMENT:
1707				len += sizeof(struct ip6_frag);
1708				break;
1709			case IPPROTO_AH:
1710				len += (ip6e->ip6e_len + 2) << 2;
1711				break;
1712			default:
1713				len += (ip6e->ip6e_len + 1) << 3;
1714				break;
1715			}
1716			nxt = ip6e->ip6e_nxt;
1717		}
1718		if (ip6e)
1719			return (&ip6e->ip6e_nxt);
1720		else
1721			return NULL;
1722	}
1723}
1724
1725/*
1726 * get next header offset.  m will be retained.
1727 */
1728int
1729ip6_nexthdr(struct mbuf *m, int off, int proto, int *nxtp)
1730{
1731	struct ip6_hdr ip6;
1732	struct ip6_ext ip6e;
1733	struct ip6_frag fh;
1734
1735	/* just in case */
1736	if (m == NULL)
1737		panic("ip6_nexthdr: m == NULL");
1738	if ((m->m_flags & M_PKTHDR) == 0 || m->m_pkthdr.len < off)
1739		return -1;
1740
1741	switch (proto) {
1742	case IPPROTO_IPV6:
1743		if (m->m_pkthdr.len < off + sizeof(ip6))
1744			return -1;
1745		m_copydata(m, off, sizeof(ip6), (caddr_t)&ip6);
1746		if (nxtp)
1747			*nxtp = ip6.ip6_nxt;
1748		off += sizeof(ip6);
1749		return off;
1750
1751	case IPPROTO_FRAGMENT:
1752		/*
1753		 * terminate parsing if it is not the first fragment,
1754		 * it does not make sense to parse through it.
1755		 */
1756		if (m->m_pkthdr.len < off + sizeof(fh))
1757			return -1;
1758		m_copydata(m, off, sizeof(fh), (caddr_t)&fh);
1759		/* IP6F_OFF_MASK = 0xfff8(BigEndian), 0xf8ff(LittleEndian) */
1760		if (fh.ip6f_offlg & IP6F_OFF_MASK)
1761			return -1;
1762		if (nxtp)
1763			*nxtp = fh.ip6f_nxt;
1764		off += sizeof(struct ip6_frag);
1765		return off;
1766
1767	case IPPROTO_AH:
1768		if (m->m_pkthdr.len < off + sizeof(ip6e))
1769			return -1;
1770		m_copydata(m, off, sizeof(ip6e), (caddr_t)&ip6e);
1771		if (nxtp)
1772			*nxtp = ip6e.ip6e_nxt;
1773		off += (ip6e.ip6e_len + 2) << 2;
1774		return off;
1775
1776	case IPPROTO_HOPOPTS:
1777	case IPPROTO_ROUTING:
1778	case IPPROTO_DSTOPTS:
1779		if (m->m_pkthdr.len < off + sizeof(ip6e))
1780			return -1;
1781		m_copydata(m, off, sizeof(ip6e), (caddr_t)&ip6e);
1782		if (nxtp)
1783			*nxtp = ip6e.ip6e_nxt;
1784		off += (ip6e.ip6e_len + 1) << 3;
1785		return off;
1786
1787	case IPPROTO_NONE:
1788	case IPPROTO_ESP:
1789	case IPPROTO_IPCOMP:
1790		/* give up */
1791		return -1;
1792
1793	default:
1794		return -1;
1795	}
1796
1797	return -1;
1798}
1799
1800/*
1801 * get offset for the last header in the chain.  m will be kept untainted.
1802 */
1803int
1804ip6_lasthdr(struct mbuf *m, int off, int proto, int *nxtp)
1805{
1806	int newoff;
1807	int nxt;
1808
1809	if (!nxtp) {
1810		nxt = -1;
1811		nxtp = &nxt;
1812	}
1813	while (1) {
1814		newoff = ip6_nexthdr(m, off, proto, nxtp);
1815		if (newoff < 0)
1816			return off;
1817		else if (newoff < off)
1818			return -1;	/* invalid */
1819		else if (newoff == off)
1820			return newoff;
1821
1822		off = newoff;
1823		proto = *nxtp;
1824	}
1825}
1826
1827static struct ip6aux *
1828ip6_addaux(struct mbuf *m)
1829{
1830	struct m_tag *mtag;
1831
1832	mtag = m_tag_find(m, PACKET_TAG_IPV6_INPUT, NULL);
1833	if (!mtag) {
1834		mtag = m_tag_get(PACKET_TAG_IPV6_INPUT, sizeof(struct ip6aux),
1835		    M_NOWAIT);
1836		if (mtag) {
1837			m_tag_prepend(m, mtag);
1838			bzero(mtag + 1, sizeof(struct ip6aux));
1839		}
1840	}
1841	return mtag ? (struct ip6aux *)(mtag + 1) : NULL;
1842}
1843
1844static struct ip6aux *
1845ip6_findaux(struct mbuf *m)
1846{
1847	struct m_tag *mtag;
1848
1849	mtag = m_tag_find(m, PACKET_TAG_IPV6_INPUT, NULL);
1850	return mtag ? (struct ip6aux *)(mtag + 1) : NULL;
1851}
1852
1853static void
1854ip6_delaux(struct mbuf *m)
1855{
1856	struct m_tag *mtag;
1857
1858	mtag = m_tag_find(m, PACKET_TAG_IPV6_INPUT, NULL);
1859	if (mtag)
1860		m_tag_delete(m, mtag);
1861}
1862
1863/*
1864 * System control for IP6
1865 */
1866
1867u_char	inet6ctlerrmap[PRC_NCMDS] = {
1868	0,		0,		0,		0,
1869	0,		EMSGSIZE,	EHOSTDOWN,	EHOSTUNREACH,
1870	EHOSTUNREACH,	EHOSTUNREACH,	ECONNREFUSED,	ECONNREFUSED,
1871	EMSGSIZE,	EHOSTUNREACH,	0,		0,
1872	0,		0,		0,		0,
1873	ENOPROTOOPT
1874};
1875