2 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
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
29 * $KAME: ip6_input.c,v 1.259 2002/01/21 04:58:09 jinmei Exp $
33 * Copyright (c) 1982, 1986, 1988, 1993
34 * The Regents of the University of California. All rights reserved.
36 * Redistribution and use in source and binary forms, with or without
37 * modification, are permitted provided that the following conditions
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.
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
60 * @(#)ip_input.c 8.2 (Berkeley) 1/4/94
63 #include <sys/cdefs.h>
64 __FBSDID("$FreeBSD$");
67 #include "opt_inet6.h"
68 #include "opt_ipsec.h"
70 #include <sys/param.h>
71 #include <sys/systm.h>
72 #include <sys/malloc.h>
75 #include <sys/domain.h>
76 #include <sys/protosw.h>
77 #include <sys/socket.h>
78 #include <sys/socketvar.h>
79 #include <sys/errno.h>
81 #include <sys/kernel.h>
82 #include <sys/syslog.h>
83 #include <sys/vimage.h>
86 #include <net/if_types.h>
87 #include <net/if_dl.h>
88 #include <net/route.h>
89 #include <net/netisr.h>
92 #include <netinet/in.h>
93 #include <netinet/in_systm.h>
95 #include <netinet/ip.h>
96 #include <netinet/ip_icmp.h>
98 #include <netinet/ip6.h>
99 #include <netinet6/in6_var.h>
100 #include <netinet6/ip6_var.h>
101 #include <netinet/in_pcb.h>
102 #include <netinet/icmp6.h>
103 #include <netinet6/scope6_var.h>
104 #include <netinet6/in6_ifattach.h>
105 #include <netinet6/nd6.h>
108 #include <netipsec/ipsec.h>
109 #include <netinet6/ip6_ipsec.h>
110 #include <netipsec/ipsec6.h>
113 #include <netinet6/ip6protosw.h>
115 extern struct domain inet6domain;
117 u_char ip6_protox[IPPROTO_MAX];
118 static struct ifqueue ip6intrq;
119 static int ip6qmaxlen = IFQ_MAXLEN;
120 struct in6_ifaddr *in6_ifaddr;
122 extern struct callout in6_tmpaddrtimer_ch;
124 int ip6_forward_srcrt; /* XXX */
125 int ip6_sourcecheck; /* XXX */
126 int ip6_sourcecheck_interval; /* XXX */
128 int ip6_ours_check_algorithm;
130 struct pfil_head inet6_pfil_hook;
132 struct ip6stat ip6stat;
134 static void ip6_init2(void *);
135 static struct ip6aux *ip6_setdstifaddr(struct mbuf *, struct in6_ifaddr *);
136 static int ip6_hopopts_input(u_int32_t *, u_int32_t *, struct mbuf **, int *);
138 static struct mbuf *ip6_pullexthdr(struct mbuf *, size_t, int);
142 * IP6 initialization: fill in IP6 protocol switch table.
143 * All protocols not implemented in kernel go to raw IP6 protocol handler.
148 struct ip6protosw *pr;
152 if (sizeof(struct protosw) != sizeof(struct ip6protosw))
153 panic("sizeof(protosw) != sizeof(ip6protosw)");
155 pr = (struct ip6protosw *)pffindproto(PF_INET6, IPPROTO_RAW, SOCK_RAW);
159 /* Initialize the entire ip_protox[] array to IPPROTO_RAW. */
160 for (i = 0; i < IPPROTO_MAX; i++)
161 ip6_protox[i] = pr - inet6sw;
163 * Cycle through IP protocols and put them into the appropriate place
166 for (pr = (struct ip6protosw *)inet6domain.dom_protosw;
167 pr < (struct ip6protosw *)inet6domain.dom_protoswNPROTOSW; pr++)
168 if (pr->pr_domain->dom_family == PF_INET6 &&
169 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) {
170 /* Be careful to only index valid IP protocols. */
171 if (pr->pr_protocol < IPPROTO_MAX)
172 ip6_protox[pr->pr_protocol] = pr - inet6sw;
175 /* Initialize packet filter hooks. */
176 inet6_pfil_hook.ph_type = PFIL_TYPE_AF;
177 inet6_pfil_hook.ph_af = AF_INET6;
178 if ((i = pfil_head_register(&inet6_pfil_hook)) != 0)
179 printf("%s: WARNING: unable to register pfil hook, "
180 "error %d\n", __func__, i);
182 ip6intrq.ifq_maxlen = V_ip6qmaxlen;
183 mtx_init(&ip6intrq.ifq_mtx, "ip6_inq", NULL, MTX_DEF);
184 netisr_register(NETISR_IPV6, ip6_input, &ip6intrq, 0);
186 addrsel_policy_init();
189 V_ip6_desync_factor = arc4random() % MAX_TEMP_DESYNC_FACTOR;
193 ip6_init2(void *dummy)
197 callout_init(&V_nd6_timer_ch, 0);
198 callout_reset(&V_nd6_timer_ch, hz, nd6_timer, NULL);
200 /* timer for regeneranation of temporary addresses randomize ID */
201 callout_init(&V_in6_tmpaddrtimer_ch, 0);
202 callout_reset(&V_in6_tmpaddrtimer_ch,
203 (V_ip6_temp_preferred_lifetime - V_ip6_desync_factor -
204 V_ip6_temp_regen_advance) * hz,
205 in6_tmpaddrtimer, NULL);
209 /* This must be after route_init(), which is now SI_ORDER_THIRD */
210 SYSINIT(netinet6init2, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, ip6_init2, NULL);
212 extern struct route_in6 ip6_forward_rt;
215 ip6_input(struct mbuf *m)
218 int off = sizeof(struct ip6_hdr), nest;
220 u_int32_t rtalert = ~0;
222 struct ifnet *deliverifp = NULL;
223 struct in6_addr odst;
228 * should the inner packet be considered authentic?
229 * see comment in ah4_input().
230 * NB: m cannot be NULL when passed to the input routine
233 m->m_flags &= ~M_AUTHIPHDR;
234 m->m_flags &= ~M_AUTHIPDGM;
239 * make sure we don't have onion peering information into m_tag.
246 if (m->m_flags & M_EXT) {
248 V_ip6stat.ip6s_mext2m++;
250 V_ip6stat.ip6s_mext1++;
252 #define M2MMAX (sizeof(V_ip6stat.ip6s_m2m)/sizeof(V_ip6stat.ip6s_m2m[0]))
254 if (m->m_flags & M_LOOP) {
255 V_ip6stat.ip6s_m2m[V_loif[0].if_index]++; /* XXX */
256 } else if (m->m_pkthdr.rcvif->if_index < M2MMAX)
257 V_ip6stat.ip6s_m2m[m->m_pkthdr.rcvif->if_index]++;
259 V_ip6stat.ip6s_m2m[0]++;
265 /* drop the packet if IPv6 operation is disabled on the IF */
266 if ((ND_IFINFO(m->m_pkthdr.rcvif)->flags & ND6_IFF_IFDISABLED)) {
271 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_receive);
272 V_ip6stat.ip6s_total++;
274 #ifndef PULLDOWN_TEST
276 * L2 bridge code and some other code can return mbuf chain
277 * that does not conform to KAME requirement. too bad.
278 * XXX: fails to join if interface MTU > MCLBYTES. jumbogram?
280 if (m && m->m_next != NULL && m->m_pkthdr.len < MCLBYTES) {
283 MGETHDR(n, M_DONTWAIT, MT_HEADER);
286 if (n && n->m_pkthdr.len > MHLEN) {
287 MCLGET(n, M_DONTWAIT);
288 if ((n->m_flags & M_EXT) == 0) {
295 return; /* ENOBUFS */
298 m_copydata(m, 0, n->m_pkthdr.len, mtod(n, caddr_t));
299 n->m_len = n->m_pkthdr.len;
303 IP6_EXTHDR_CHECK(m, 0, sizeof(struct ip6_hdr), /* nothing */);
306 if (m->m_len < sizeof(struct ip6_hdr)) {
308 inifp = m->m_pkthdr.rcvif;
309 if ((m = m_pullup(m, sizeof(struct ip6_hdr))) == NULL) {
310 V_ip6stat.ip6s_toosmall++;
311 in6_ifstat_inc(inifp, ifs6_in_hdrerr);
316 ip6 = mtod(m, struct ip6_hdr *);
318 if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) {
319 V_ip6stat.ip6s_badvers++;
320 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_hdrerr);
324 V_ip6stat.ip6s_nxthist[ip6->ip6_nxt]++;
327 * Check against address spoofing/corruption.
329 if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_src) ||
330 IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_dst)) {
332 * XXX: "badscope" is not very suitable for a multicast source.
334 V_ip6stat.ip6s_badscope++;
335 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
338 if (IN6_IS_ADDR_MC_INTFACELOCAL(&ip6->ip6_dst) &&
339 !(m->m_flags & M_LOOP)) {
341 * In this case, the packet should come from the loopback
342 * interface. However, we cannot just check the if_flags,
343 * because ip6_mloopback() passes the "actual" interface
344 * as the outgoing/incoming interface.
346 V_ip6stat.ip6s_badscope++;
347 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
352 if (altq_input != NULL && (*altq_input)(m, AF_INET6) == 0) {
353 /* packet is dropped by traffic conditioner */
358 * The following check is not documented in specs. A malicious
359 * party may be able to use IPv4 mapped addr to confuse tcp/udp stack
360 * and bypass security checks (act as if it was from 127.0.0.1 by using
361 * IPv6 src ::ffff:127.0.0.1). Be cautious.
363 * This check chokes if we are in an SIIT cloud. As none of BSDs
364 * support IPv4-less kernel compilation, we cannot support SIIT
365 * environment at all. So, it makes more sense for us to reject any
366 * malicious packets for non-SIIT environment, than try to do a
367 * partial support for SIIT environment.
369 if (IN6_IS_ADDR_V4MAPPED(&ip6->ip6_src) ||
370 IN6_IS_ADDR_V4MAPPED(&ip6->ip6_dst)) {
371 V_ip6stat.ip6s_badscope++;
372 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
377 * Reject packets with IPv4 compatible addresses (auto tunnel).
379 * The code forbids auto tunnel relay case in RFC1933 (the check is
380 * stronger than RFC1933). We may want to re-enable it if mech-xx
381 * is revised to forbid relaying case.
383 if (IN6_IS_ADDR_V4COMPAT(&ip6->ip6_src) ||
384 IN6_IS_ADDR_V4COMPAT(&ip6->ip6_dst)) {
385 V_ip6stat.ip6s_badscope++;
386 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
392 * Run through list of hooks for input packets.
394 * NB: Beware of the destination address changing
395 * (e.g. by NAT rewriting). When this happens,
396 * tell ip6_forward to do the right thing.
400 /* Jump over all PFIL processing if hooks are not active. */
401 if (!PFIL_HOOKED(&inet6_pfil_hook))
404 if (pfil_run_hooks(&inet6_pfil_hook, &m, m->m_pkthdr.rcvif, PFIL_IN, NULL))
406 if (m == NULL) /* consumed by filter */
408 ip6 = mtod(m, struct ip6_hdr *);
409 srcrt = !IN6_ARE_ADDR_EQUAL(&odst, &ip6->ip6_dst);
413 * Disambiguate address scope zones (if there is ambiguity).
414 * We first make sure that the original source or destination address
415 * is not in our internal form for scoped addresses. Such addresses
416 * are not necessarily invalid spec-wise, but we cannot accept them due
417 * to the usage conflict.
418 * in6_setscope() then also checks and rejects the cases where src or
419 * dst are the loopback address and the receiving interface
422 if (in6_clearscope(&ip6->ip6_src) || in6_clearscope(&ip6->ip6_dst)) {
423 V_ip6stat.ip6s_badscope++; /* XXX */
426 if (in6_setscope(&ip6->ip6_src, m->m_pkthdr.rcvif, NULL) ||
427 in6_setscope(&ip6->ip6_dst, m->m_pkthdr.rcvif, NULL)) {
428 V_ip6stat.ip6s_badscope++;
435 if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
436 struct in6_multi *in6m = 0;
438 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_mcast);
440 * See if we belong to the destination multicast group on the
443 IN6_LOOKUP_MULTI(ip6->ip6_dst, m->m_pkthdr.rcvif, in6m);
446 else if (!ip6_mrouter) {
447 V_ip6stat.ip6s_notmember++;
448 V_ip6stat.ip6s_cantforward++;
449 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
452 deliverifp = m->m_pkthdr.rcvif;
459 if (V_ip6_forward_rt.ro_rt != NULL &&
460 (V_ip6_forward_rt.ro_rt->rt_flags & RTF_UP) != 0 &&
461 IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst,
462 &((struct sockaddr_in6 *)(&V_ip6_forward_rt.ro_dst))->sin6_addr))
463 V_ip6stat.ip6s_forward_cachehit++;
465 struct sockaddr_in6 *dst6;
467 if (V_ip6_forward_rt.ro_rt) {
468 /* route is down or destination is different */
469 V_ip6stat.ip6s_forward_cachemiss++;
470 RTFREE(V_ip6_forward_rt.ro_rt);
471 V_ip6_forward_rt.ro_rt = 0;
474 bzero(&V_ip6_forward_rt.ro_dst, sizeof(struct sockaddr_in6));
475 dst6 = (struct sockaddr_in6 *)&V_ip6_forward_rt.ro_dst;
476 dst6->sin6_len = sizeof(struct sockaddr_in6);
477 dst6->sin6_family = AF_INET6;
478 dst6->sin6_addr = ip6->ip6_dst;
480 rtalloc((struct route *)&V_ip6_forward_rt);
483 #define rt6_key(r) ((struct sockaddr_in6 *)((r)->rt_nodes->rn_key))
486 * Accept the packet if the forwarding interface to the destination
487 * according to the routing table is the loopback interface,
488 * unless the associated route has a gateway.
489 * Note that this approach causes to accept a packet if there is a
490 * route to the loopback interface for the destination of the packet.
491 * But we think it's even useful in some situations, e.g. when using
492 * a special daemon which wants to intercept the packet.
494 * XXX: some OSes automatically make a cloned route for the destination
495 * of an outgoing packet. If the outgoing interface of the packet
496 * is a loopback one, the kernel would consider the packet to be
497 * accepted, even if we have no such address assinged on the interface.
498 * We check the cloned flag of the route entry to reject such cases,
499 * assuming that route entries for our own addresses are not made by
500 * cloning (it should be true because in6_addloop explicitly installs
501 * the host route). However, we might have to do an explicit check
502 * while it would be less efficient. Or, should we rather install a
503 * reject route for such a case?
505 if (V_ip6_forward_rt.ro_rt &&
506 (V_ip6_forward_rt.ro_rt->rt_flags &
507 (RTF_HOST|RTF_GATEWAY)) == RTF_HOST &&
509 !(V_ip6_forward_rt.ro_rt->rt_flags & RTF_WASCLONED) &&
512 !(V_ip6_forward_rt.ro_rt->rt_flags & RTF_CLONED) &&
516 * The check below is redundant since the comparison of
517 * the destination and the key of the rtentry has
518 * already done through looking up the routing table.
520 IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst,
521 &rt6_key(V_ip6_forward_rt.ro_rt)->sin6_addr)
523 V_ip6_forward_rt.ro_rt->rt_ifp->if_type == IFT_LOOP) {
524 struct in6_ifaddr *ia6 =
525 (struct in6_ifaddr *)V_ip6_forward_rt.ro_rt->rt_ifa;
528 * record address information into m_tag.
530 (void)ip6_setdstifaddr(m, ia6);
533 * packets to a tentative, duplicated, or somehow invalid
534 * address must not be accepted.
536 if (!(ia6->ia6_flags & IN6_IFF_NOTREADY)) {
537 /* this address is ready */
539 deliverifp = ia6->ia_ifp; /* correct? */
540 /* Count the packet in the ip address stats */
541 ia6->ia_ifa.if_ipackets++;
542 ia6->ia_ifa.if_ibytes += m->m_pkthdr.len;
545 char ip6bufs[INET6_ADDRSTRLEN];
546 char ip6bufd[INET6_ADDRSTRLEN];
547 /* address is not ready, so discard the packet. */
549 "ip6_input: packet to an unready address %s->%s\n",
550 ip6_sprintf(ip6bufs, &ip6->ip6_src),
551 ip6_sprintf(ip6bufd, &ip6->ip6_dst)));
558 * FAITH (Firewall Aided Internet Translator)
560 if (V_ip6_keepfaith) {
561 if (V_ip6_forward_rt.ro_rt && V_ip6_forward_rt.ro_rt->rt_ifp
562 && V_ip6_forward_rt.ro_rt->rt_ifp->if_type == IFT_FAITH) {
563 /* XXX do we need more sanity checks? */
565 deliverifp = V_ip6_forward_rt.ro_rt->rt_ifp; /* faith */
571 * Now there is no reason to process the packet if it's not our own
572 * and we're not a router.
574 if (!V_ip6_forwarding) {
575 V_ip6stat.ip6s_cantforward++;
576 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
582 * record address information into m_tag, if we don't have one yet.
583 * note that we are unable to record it, if the address is not listed
584 * as our interface address (e.g. multicast addresses, addresses
585 * within FAITH prefixes and such).
587 if (deliverifp && !ip6_getdstifaddr(m)) {
588 struct in6_ifaddr *ia6;
590 ia6 = in6_ifawithifp(deliverifp, &ip6->ip6_dst);
592 if (!ip6_setdstifaddr(m, ia6)) {
594 * XXX maybe we should drop the packet here,
595 * as we could not provide enough information
596 * to the upper layers.
603 * Process Hop-by-Hop options header if it's contained.
604 * m may be modified in ip6_hopopts_input().
605 * If a JumboPayload option is included, plen will also be modified.
607 plen = (u_int32_t)ntohs(ip6->ip6_plen);
608 if (ip6->ip6_nxt == IPPROTO_HOPOPTS) {
611 if (ip6_hopopts_input(&plen, &rtalert, &m, &off)) {
612 #if 0 /*touches NULL pointer*/
613 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
615 return; /* m have already been freed */
619 ip6 = mtod(m, struct ip6_hdr *);
622 * if the payload length field is 0 and the next header field
623 * indicates Hop-by-Hop Options header, then a Jumbo Payload
624 * option MUST be included.
626 if (ip6->ip6_plen == 0 && plen == 0) {
628 * Note that if a valid jumbo payload option is
629 * contained, ip6_hopopts_input() must set a valid
630 * (non-zero) payload length to the variable plen.
632 V_ip6stat.ip6s_badoptions++;
633 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
634 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_hdrerr);
635 icmp6_error(m, ICMP6_PARAM_PROB,
636 ICMP6_PARAMPROB_HEADER,
637 (caddr_t)&ip6->ip6_plen - (caddr_t)ip6);
640 #ifndef PULLDOWN_TEST
641 /* ip6_hopopts_input() ensures that mbuf is contiguous */
642 hbh = (struct ip6_hbh *)(ip6 + 1);
644 IP6_EXTHDR_GET(hbh, struct ip6_hbh *, m, sizeof(struct ip6_hdr),
645 sizeof(struct ip6_hbh));
647 V_ip6stat.ip6s_tooshort++;
654 * If we are acting as a router and the packet contains a
655 * router alert option, see if we know the option value.
656 * Currently, we only support the option value for MLD, in which
657 * case we should pass the packet to the multicast routing
660 if (rtalert != ~0 && V_ip6_forwarding) {
662 case IP6OPT_RTALERT_MLD:
667 * RFC2711 requires unrecognized values must be
677 * Check that the amount of data in the buffers
678 * is as at least much as the IPv6 header would have us expect.
679 * Trim mbufs if longer than we expect.
680 * Drop packet if shorter than we expect.
682 if (m->m_pkthdr.len - sizeof(struct ip6_hdr) < plen) {
683 V_ip6stat.ip6s_tooshort++;
684 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_truncated);
687 if (m->m_pkthdr.len > sizeof(struct ip6_hdr) + plen) {
688 if (m->m_len == m->m_pkthdr.len) {
689 m->m_len = sizeof(struct ip6_hdr) + plen;
690 m->m_pkthdr.len = sizeof(struct ip6_hdr) + plen;
692 m_adj(m, sizeof(struct ip6_hdr) + plen - m->m_pkthdr.len);
696 * Forward if desirable.
698 if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
700 * If we are acting as a multicast router, all
701 * incoming multicast packets are passed to the
702 * kernel-level multicast forwarding function.
703 * The packet is returned (relatively) intact; if
704 * ip6_mforward() returns a non-zero value, the packet
705 * must be discarded, else it may be accepted below.
707 if (ip6_mrouter && ip6_mforward &&
708 ip6_mforward(ip6, m->m_pkthdr.rcvif, m)) {
709 V_ip6stat.ip6s_cantforward++;
718 ip6_forward(m, srcrt);
722 ip6 = mtod(m, struct ip6_hdr *);
725 * Malicious party may be able to use IPv4 mapped addr to confuse
726 * tcp/udp stack and bypass security checks (act as if it was from
727 * 127.0.0.1 by using IPv6 src ::ffff:127.0.0.1). Be cautious.
729 * For SIIT end node behavior, you may want to disable the check.
730 * However, you will become vulnerable to attacks using IPv4 mapped
733 if (IN6_IS_ADDR_V4MAPPED(&ip6->ip6_src) ||
734 IN6_IS_ADDR_V4MAPPED(&ip6->ip6_dst)) {
735 V_ip6stat.ip6s_badscope++;
736 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
741 * Tell launch routine the next header
743 V_ip6stat.ip6s_delivered++;
744 in6_ifstat_inc(deliverifp, ifs6_in_deliver);
747 while (nxt != IPPROTO_DONE) {
748 if (V_ip6_hdrnestlimit && (++nest > V_ip6_hdrnestlimit)) {
749 V_ip6stat.ip6s_toomanyhdr++;
754 * protection against faulty packet - there should be
755 * more sanity checks in header chain processing.
757 if (m->m_pkthdr.len < off) {
758 V_ip6stat.ip6s_tooshort++;
759 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_truncated);
765 * enforce IPsec policy checking if we are seeing last header.
766 * note that we do not visit this with protocols with pcb layer
767 * code - like udp/tcp/raw ip.
769 if (ip6_ipsec_input(m, nxt))
772 nxt = (*inet6sw[ip6_protox[nxt]].pr_input)(&m, &off, nxt);
780 * set/grab in6_ifaddr correspond to IPv6 destination address.
781 * XXX backward compatibility wrapper
783 static struct ip6aux *
784 ip6_setdstifaddr(struct mbuf *m, struct in6_ifaddr *ia6)
788 ip6a = ip6_addaux(m);
790 ip6a->ip6a_dstia6 = ia6;
791 return ip6a; /* NULL if failed to set */
795 ip6_getdstifaddr(struct mbuf *m)
799 ip6a = ip6_findaux(m);
801 return ip6a->ip6a_dstia6;
807 * Hop-by-Hop options header processing. If a valid jumbo payload option is
808 * included, the real payload length will be stored in plenp.
810 * rtalertp - XXX: should be stored more smart way
813 ip6_hopopts_input(u_int32_t *plenp, u_int32_t *rtalertp,
814 struct mbuf **mp, int *offp)
816 struct mbuf *m = *mp;
817 int off = *offp, hbhlen;
821 /* validation of the length of the header */
822 #ifndef PULLDOWN_TEST
823 IP6_EXTHDR_CHECK(m, off, sizeof(*hbh), -1);
824 hbh = (struct ip6_hbh *)(mtod(m, caddr_t) + off);
825 hbhlen = (hbh->ip6h_len + 1) << 3;
827 IP6_EXTHDR_CHECK(m, off, hbhlen, -1);
828 hbh = (struct ip6_hbh *)(mtod(m, caddr_t) + off);
830 IP6_EXTHDR_GET(hbh, struct ip6_hbh *, m,
831 sizeof(struct ip6_hdr), sizeof(struct ip6_hbh));
833 V_ip6stat.ip6s_tooshort++;
836 hbhlen = (hbh->ip6h_len + 1) << 3;
837 IP6_EXTHDR_GET(hbh, struct ip6_hbh *, m, sizeof(struct ip6_hdr),
840 V_ip6stat.ip6s_tooshort++;
845 hbhlen -= sizeof(struct ip6_hbh);
846 opt = (u_int8_t *)hbh + sizeof(struct ip6_hbh);
848 if (ip6_process_hopopts(m, (u_int8_t *)hbh + sizeof(struct ip6_hbh),
849 hbhlen, rtalertp, plenp) < 0)
858 * Search header for all Hop-by-hop options and process each option.
859 * This function is separate from ip6_hopopts_input() in order to
860 * handle a case where the sending node itself process its hop-by-hop
861 * options header. In such a case, the function is called from ip6_output().
863 * The function assumes that hbh header is located right after the IPv6 header
864 * (RFC2460 p7), opthead is pointer into data content in m, and opthead to
865 * opthead + hbhlen is located in continuous memory region.
868 ip6_process_hopopts(struct mbuf *m, u_int8_t *opthead, int hbhlen,
869 u_int32_t *rtalertp, u_int32_t *plenp)
873 u_int8_t *opt = opthead;
874 u_int16_t rtalert_val;
876 const int erroff = sizeof(struct ip6_hdr) + sizeof(struct ip6_hbh);
878 for (; hbhlen > 0; hbhlen -= optlen, opt += optlen) {
884 if (hbhlen < IP6OPT_MINLEN) {
885 V_ip6stat.ip6s_toosmall++;
888 optlen = *(opt + 1) + 2;
890 case IP6OPT_ROUTER_ALERT:
891 /* XXX may need check for alignment */
892 if (hbhlen < IP6OPT_RTALERT_LEN) {
893 V_ip6stat.ip6s_toosmall++;
896 if (*(opt + 1) != IP6OPT_RTALERT_LEN - 2) {
898 icmp6_error(m, ICMP6_PARAM_PROB,
899 ICMP6_PARAMPROB_HEADER,
900 erroff + opt + 1 - opthead);
903 optlen = IP6OPT_RTALERT_LEN;
904 bcopy((caddr_t)(opt + 2), (caddr_t)&rtalert_val, 2);
905 *rtalertp = ntohs(rtalert_val);
908 /* XXX may need check for alignment */
909 if (hbhlen < IP6OPT_JUMBO_LEN) {
910 V_ip6stat.ip6s_toosmall++;
913 if (*(opt + 1) != IP6OPT_JUMBO_LEN - 2) {
915 icmp6_error(m, ICMP6_PARAM_PROB,
916 ICMP6_PARAMPROB_HEADER,
917 erroff + opt + 1 - opthead);
920 optlen = IP6OPT_JUMBO_LEN;
923 * IPv6 packets that have non 0 payload length
924 * must not contain a jumbo payload option.
926 ip6 = mtod(m, struct ip6_hdr *);
928 V_ip6stat.ip6s_badoptions++;
929 icmp6_error(m, ICMP6_PARAM_PROB,
930 ICMP6_PARAMPROB_HEADER,
931 erroff + opt - opthead);
936 * We may see jumbolen in unaligned location, so
937 * we'd need to perform bcopy().
939 bcopy(opt + 2, &jumboplen, sizeof(jumboplen));
940 jumboplen = (u_int32_t)htonl(jumboplen);
944 * if there are multiple jumbo payload options,
945 * *plenp will be non-zero and the packet will be
947 * the behavior may need some debate in ipngwg -
948 * multiple options does not make sense, however,
949 * there's no explicit mention in specification.
952 V_ip6stat.ip6s_badoptions++;
953 icmp6_error(m, ICMP6_PARAM_PROB,
954 ICMP6_PARAMPROB_HEADER,
955 erroff + opt + 2 - opthead);
961 * jumbo payload length must be larger than 65535.
963 if (jumboplen <= IPV6_MAXPACKET) {
964 V_ip6stat.ip6s_badoptions++;
965 icmp6_error(m, ICMP6_PARAM_PROB,
966 ICMP6_PARAMPROB_HEADER,
967 erroff + opt + 2 - opthead);
973 default: /* unknown option */
974 if (hbhlen < IP6OPT_MINLEN) {
975 V_ip6stat.ip6s_toosmall++;
978 optlen = ip6_unknown_opt(opt, m,
979 erroff + opt - opthead);
995 * Unknown option processing.
996 * The third argument `off' is the offset from the IPv6 header to the option,
997 * which is necessary if the IPv6 header the and option header and IPv6 header
998 * is not continuous in order to return an ICMPv6 error.
1001 ip6_unknown_opt(u_int8_t *optp, struct mbuf *m, int off)
1003 struct ip6_hdr *ip6;
1005 switch (IP6OPT_TYPE(*optp)) {
1006 case IP6OPT_TYPE_SKIP: /* ignore the option */
1007 return ((int)*(optp + 1));
1008 case IP6OPT_TYPE_DISCARD: /* silently discard */
1011 case IP6OPT_TYPE_FORCEICMP: /* send ICMP even if multicasted */
1012 V_ip6stat.ip6s_badoptions++;
1013 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_OPTION, off);
1015 case IP6OPT_TYPE_ICMP: /* send ICMP if not multicasted */
1016 V_ip6stat.ip6s_badoptions++;
1017 ip6 = mtod(m, struct ip6_hdr *);
1018 if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) ||
1019 (m->m_flags & (M_BCAST|M_MCAST)))
1022 icmp6_error(m, ICMP6_PARAM_PROB,
1023 ICMP6_PARAMPROB_OPTION, off);
1027 m_freem(m); /* XXX: NOTREACHED */
1032 * Create the "control" list for this pcb.
1033 * These functions will not modify mbuf chain at all.
1035 * With KAME mbuf chain restriction:
1036 * The routine will be called from upper layer handlers like tcp6_input().
1037 * Thus the routine assumes that the caller (tcp6_input) have already
1038 * called IP6_EXTHDR_CHECK() and all the extension headers are located in the
1039 * very first mbuf on the mbuf chain.
1041 * ip6_savecontrol_v4 will handle those options that are possible to be
1042 * set on a v4-mapped socket.
1043 * ip6_savecontrol will directly call ip6_savecontrol_v4 to handle those
1044 * options and handle the v6-only ones itself.
1047 ip6_savecontrol_v4(struct inpcb *inp, struct mbuf *m, struct mbuf **mp,
1050 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
1053 if ((inp->inp_socket->so_options & SO_TIMESTAMP) != 0) {
1057 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv),
1058 SCM_TIMESTAMP, SOL_SOCKET);
1060 mp = &(*mp)->m_next;
1064 if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) {
1070 #define IS2292(inp, x, y) (((inp)->inp_flags & IN6P_RFC2292) ? (x) : (y))
1071 /* RFC 2292 sec. 5 */
1072 if ((inp->inp_flags & IN6P_PKTINFO) != 0) {
1073 struct in6_pktinfo pi6;
1075 bcopy(&ip6->ip6_dst, &pi6.ipi6_addr, sizeof(struct in6_addr));
1076 in6_clearscope(&pi6.ipi6_addr); /* XXX */
1078 (m && m->m_pkthdr.rcvif) ? m->m_pkthdr.rcvif->if_index : 0;
1080 *mp = sbcreatecontrol((caddr_t) &pi6,
1081 sizeof(struct in6_pktinfo),
1082 IS2292(inp, IPV6_2292PKTINFO, IPV6_PKTINFO), IPPROTO_IPV6);
1084 mp = &(*mp)->m_next;
1087 if ((inp->inp_flags & IN6P_HOPLIMIT) != 0) {
1088 int hlim = ip6->ip6_hlim & 0xff;
1090 *mp = sbcreatecontrol((caddr_t) &hlim, sizeof(int),
1091 IS2292(inp, IPV6_2292HOPLIMIT, IPV6_HOPLIMIT),
1094 mp = &(*mp)->m_next;
1103 ip6_savecontrol(struct inpcb *in6p, struct mbuf *m, struct mbuf **mp)
1105 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
1108 mp = ip6_savecontrol_v4(in6p, m, mp, &v4only);
1112 if ((in6p->in6p_flags & IN6P_TCLASS) != 0) {
1116 flowinfo = (u_int32_t)ntohl(ip6->ip6_flow & IPV6_FLOWINFO_MASK);
1119 tclass = flowinfo & 0xff;
1120 *mp = sbcreatecontrol((caddr_t) &tclass, sizeof(tclass),
1121 IPV6_TCLASS, IPPROTO_IPV6);
1123 mp = &(*mp)->m_next;
1127 * IPV6_HOPOPTS socket option. Recall that we required super-user
1128 * privilege for the option (see ip6_ctloutput), but it might be too
1129 * strict, since there might be some hop-by-hop options which can be
1130 * returned to normal user.
1131 * See also RFC 2292 section 6 (or RFC 3542 section 8).
1133 if ((in6p->in6p_flags & IN6P_HOPOPTS) != 0) {
1135 * Check if a hop-by-hop options header is contatined in the
1136 * received packet, and if so, store the options as ancillary
1137 * data. Note that a hop-by-hop options header must be
1138 * just after the IPv6 header, which is assured through the
1139 * IPv6 input processing.
1141 if (ip6->ip6_nxt == IPPROTO_HOPOPTS) {
1142 struct ip6_hbh *hbh;
1144 #ifdef PULLDOWN_TEST
1148 #ifndef PULLDOWN_TEST
1149 hbh = (struct ip6_hbh *)(ip6 + 1);
1150 hbhlen = (hbh->ip6h_len + 1) << 3;
1152 ext = ip6_pullexthdr(m, sizeof(struct ip6_hdr),
1155 V_ip6stat.ip6s_tooshort++;
1158 hbh = mtod(ext, struct ip6_hbh *);
1159 hbhlen = (hbh->ip6h_len + 1) << 3;
1160 if (hbhlen != ext->m_len) {
1162 V_ip6stat.ip6s_tooshort++;
1168 * XXX: We copy the whole header even if a
1169 * jumbo payload option is included, the option which
1170 * is to be removed before returning according to
1172 * Note: this constraint is removed in RFC3542
1174 *mp = sbcreatecontrol((caddr_t)hbh, hbhlen,
1175 IS2292(in6p, IPV6_2292HOPOPTS, IPV6_HOPOPTS),
1178 mp = &(*mp)->m_next;
1179 #ifdef PULLDOWN_TEST
1185 if ((in6p->in6p_flags & (IN6P_RTHDR | IN6P_DSTOPTS)) != 0) {
1186 int nxt = ip6->ip6_nxt, off = sizeof(struct ip6_hdr);
1189 * Search for destination options headers or routing
1190 * header(s) through the header chain, and stores each
1191 * header as ancillary data.
1192 * Note that the order of the headers remains in
1193 * the chain of ancillary data.
1195 while (1) { /* is explicit loop prevention necessary? */
1196 struct ip6_ext *ip6e = NULL;
1198 #ifdef PULLDOWN_TEST
1199 struct mbuf *ext = NULL;
1203 * if it is not an extension header, don't try to
1204 * pull it from the chain.
1207 case IPPROTO_DSTOPTS:
1208 case IPPROTO_ROUTING:
1209 case IPPROTO_HOPOPTS:
1210 case IPPROTO_AH: /* is it possible? */
1216 #ifndef PULLDOWN_TEST
1217 if (off + sizeof(*ip6e) > m->m_len)
1219 ip6e = (struct ip6_ext *)(mtod(m, caddr_t) + off);
1220 if (nxt == IPPROTO_AH)
1221 elen = (ip6e->ip6e_len + 2) << 2;
1223 elen = (ip6e->ip6e_len + 1) << 3;
1224 if (off + elen > m->m_len)
1227 ext = ip6_pullexthdr(m, off, nxt);
1229 V_ip6stat.ip6s_tooshort++;
1232 ip6e = mtod(ext, struct ip6_ext *);
1233 if (nxt == IPPROTO_AH)
1234 elen = (ip6e->ip6e_len + 2) << 2;
1236 elen = (ip6e->ip6e_len + 1) << 3;
1237 if (elen != ext->m_len) {
1239 V_ip6stat.ip6s_tooshort++;
1245 case IPPROTO_DSTOPTS:
1246 if (!(in6p->in6p_flags & IN6P_DSTOPTS))
1249 *mp = sbcreatecontrol((caddr_t)ip6e, elen,
1251 IPV6_2292DSTOPTS, IPV6_DSTOPTS),
1254 mp = &(*mp)->m_next;
1256 case IPPROTO_ROUTING:
1257 if (!in6p->in6p_flags & IN6P_RTHDR)
1260 *mp = sbcreatecontrol((caddr_t)ip6e, elen,
1261 IS2292(in6p, IPV6_2292RTHDR, IPV6_RTHDR),
1264 mp = &(*mp)->m_next;
1266 case IPPROTO_HOPOPTS:
1267 case IPPROTO_AH: /* is it possible? */
1272 * other cases have been filtered in the above.
1273 * none will visit this case. here we supply
1274 * the code just in case (nxt overwritten or
1277 #ifdef PULLDOWN_TEST
1284 /* proceed with the next header. */
1286 nxt = ip6e->ip6e_nxt;
1288 #ifdef PULLDOWN_TEST
1300 ip6_notify_pmtu(struct inpcb *in6p, struct sockaddr_in6 *dst, u_int32_t *mtu)
1304 struct ip6_mtuinfo mtuctl;
1306 so = in6p->inp_socket;
1312 if (so == NULL) /* I believe this is impossible */
1313 panic("ip6_notify_pmtu: socket is NULL");
1316 bzero(&mtuctl, sizeof(mtuctl)); /* zero-clear for safety */
1317 mtuctl.ip6m_mtu = *mtu;
1318 mtuctl.ip6m_addr = *dst;
1319 if (sa6_recoverscope(&mtuctl.ip6m_addr))
1322 if ((m_mtu = sbcreatecontrol((caddr_t)&mtuctl, sizeof(mtuctl),
1323 IPV6_PATHMTU, IPPROTO_IPV6)) == NULL)
1326 if (sbappendaddr(&so->so_rcv, (struct sockaddr *)dst, NULL, m_mtu)
1329 /* XXX: should count statistics */
1336 #ifdef PULLDOWN_TEST
1338 * pull single extension header from mbuf chain. returns single mbuf that
1339 * contains the result, or NULL on error.
1341 static struct mbuf *
1342 ip6_pullexthdr(struct mbuf *m, size_t off, int nxt)
1344 struct ip6_ext ip6e;
1350 case IPPROTO_DSTOPTS:
1351 case IPPROTO_ROUTING:
1352 case IPPROTO_HOPOPTS:
1353 case IPPROTO_AH: /* is it possible? */
1356 printf("ip6_pullexthdr: invalid nxt=%d\n", nxt);
1360 m_copydata(m, off, sizeof(ip6e), (caddr_t)&ip6e);
1361 if (nxt == IPPROTO_AH)
1362 elen = (ip6e.ip6e_len + 2) << 2;
1364 elen = (ip6e.ip6e_len + 1) << 3;
1366 MGET(n, M_DONTWAIT, MT_DATA);
1367 if (n && elen >= MLEN) {
1368 MCLGET(n, M_DONTWAIT);
1369 if ((n->m_flags & M_EXT) == 0) {
1378 if (elen >= M_TRAILINGSPACE(n)) {
1383 m_copydata(m, off, elen, mtod(n, caddr_t));
1390 * Get pointer to the previous header followed by the header
1391 * currently processed.
1392 * XXX: This function supposes that
1393 * M includes all headers,
1394 * the next header field and the header length field of each header
1396 * the sum of each header length equals to OFF.
1397 * Because of these assumptions, this function must be called very
1398 * carefully. Moreover, it will not be used in the near future when
1399 * we develop `neater' mechanism to process extension headers.
1402 ip6_get_prevhdr(struct mbuf *m, int off)
1404 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
1406 if (off == sizeof(struct ip6_hdr))
1407 return (&ip6->ip6_nxt);
1410 struct ip6_ext *ip6e = NULL;
1413 len = sizeof(struct ip6_hdr);
1415 ip6e = (struct ip6_ext *)(mtod(m, caddr_t) + len);
1418 case IPPROTO_FRAGMENT:
1419 len += sizeof(struct ip6_frag);
1422 len += (ip6e->ip6e_len + 2) << 2;
1425 len += (ip6e->ip6e_len + 1) << 3;
1428 nxt = ip6e->ip6e_nxt;
1431 return (&ip6e->ip6e_nxt);
1438 * get next header offset. m will be retained.
1441 ip6_nexthdr(struct mbuf *m, int off, int proto, int *nxtp)
1444 struct ip6_ext ip6e;
1449 panic("ip6_nexthdr: m == NULL");
1450 if ((m->m_flags & M_PKTHDR) == 0 || m->m_pkthdr.len < off)
1455 if (m->m_pkthdr.len < off + sizeof(ip6))
1457 m_copydata(m, off, sizeof(ip6), (caddr_t)&ip6);
1459 *nxtp = ip6.ip6_nxt;
1463 case IPPROTO_FRAGMENT:
1465 * terminate parsing if it is not the first fragment,
1466 * it does not make sense to parse through it.
1468 if (m->m_pkthdr.len < off + sizeof(fh))
1470 m_copydata(m, off, sizeof(fh), (caddr_t)&fh);
1471 /* IP6F_OFF_MASK = 0xfff8(BigEndian), 0xf8ff(LittleEndian) */
1472 if (fh.ip6f_offlg & IP6F_OFF_MASK)
1475 *nxtp = fh.ip6f_nxt;
1476 off += sizeof(struct ip6_frag);
1480 if (m->m_pkthdr.len < off + sizeof(ip6e))
1482 m_copydata(m, off, sizeof(ip6e), (caddr_t)&ip6e);
1484 *nxtp = ip6e.ip6e_nxt;
1485 off += (ip6e.ip6e_len + 2) << 2;
1488 case IPPROTO_HOPOPTS:
1489 case IPPROTO_ROUTING:
1490 case IPPROTO_DSTOPTS:
1491 if (m->m_pkthdr.len < off + sizeof(ip6e))
1493 m_copydata(m, off, sizeof(ip6e), (caddr_t)&ip6e);
1495 *nxtp = ip6e.ip6e_nxt;
1496 off += (ip6e.ip6e_len + 1) << 3;
1501 case IPPROTO_IPCOMP:
1513 * get offset for the last header in the chain. m will be kept untainted.
1516 ip6_lasthdr(struct mbuf *m, int off, int proto, int *nxtp)
1526 newoff = ip6_nexthdr(m, off, proto, nxtp);
1529 else if (newoff < off)
1530 return -1; /* invalid */
1531 else if (newoff == off)
1540 ip6_addaux(struct mbuf *m)
1544 mtag = m_tag_find(m, PACKET_TAG_IPV6_INPUT, NULL);
1546 mtag = m_tag_get(PACKET_TAG_IPV6_INPUT, sizeof(struct ip6aux),
1549 m_tag_prepend(m, mtag);
1550 bzero(mtag + 1, sizeof(struct ip6aux));
1553 return mtag ? (struct ip6aux *)(mtag + 1) : NULL;
1557 ip6_findaux(struct mbuf *m)
1561 mtag = m_tag_find(m, PACKET_TAG_IPV6_INPUT, NULL);
1562 return mtag ? (struct ip6aux *)(mtag + 1) : NULL;
1566 ip6_delaux(struct mbuf *m)
1570 mtag = m_tag_find(m, PACKET_TAG_IPV6_INPUT, NULL);
1572 m_tag_delete(m, mtag);
1576 * System control for IP6
1579 u_char inet6ctlerrmap[PRC_NCMDS] = {
1581 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH,
1582 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED,
1583 EMSGSIZE, EHOSTUNREACH, 0, 0,