The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/netinet6/ip6_input.c

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    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/9.2/sys/netinet6/ip6_input.c 253239 2013-07-12 01:52:31Z hrs $");
   65 
   66 #include "opt_inet.h"
   67 #include "opt_inet6.h"
   68 #include "opt_ipfw.h"
   69 #include "opt_ipsec.h"
   70 #include "opt_route.h"
   71 
   72 #include <sys/param.h>
   73 #include <sys/systm.h>
   74 #include <sys/malloc.h>
   75 #include <sys/mbuf.h>
   76 #include <sys/proc.h>
   77 #include <sys/domain.h>
   78 #include <sys/protosw.h>
   79 #include <sys/socket.h>
   80 #include <sys/socketvar.h>
   81 #include <sys/errno.h>
   82 #include <sys/time.h>
   83 #include <sys/kernel.h>
   84 #include <sys/syslog.h>
   85 
   86 #include <net/if.h>
   87 #include <net/if_types.h>
   88 #include <net/if_dl.h>
   89 #include <net/route.h>
   90 #include <net/netisr.h>
   91 #include <net/pfil.h>
   92 #include <net/vnet.h>
   93 
   94 #include <netinet/in.h>
   95 #include <netinet/ip_var.h>
   96 #include <netinet/in_systm.h>
   97 #include <net/if_llatbl.h>
   98 #ifdef INET
   99 #include <netinet/ip.h>
  100 #include <netinet/ip_icmp.h>
  101 #endif /* INET */
  102 #include <netinet/ip6.h>
  103 #include <netinet6/in6_var.h>
  104 #include <netinet6/ip6_var.h>
  105 #include <netinet/in_pcb.h>
  106 #include <netinet/icmp6.h>
  107 #include <netinet6/scope6_var.h>
  108 #include <netinet6/in6_ifattach.h>
  109 #include <netinet6/nd6.h>
  110 
  111 #ifdef IPSEC
  112 #include <netipsec/ipsec.h>
  113 #include <netinet6/ip6_ipsec.h>
  114 #include <netipsec/ipsec6.h>
  115 #endif /* IPSEC */
  116 
  117 #include <netinet6/ip6protosw.h>
  118 
  119 #ifdef FLOWTABLE
  120 #include <net/flowtable.h>
  121 VNET_DECLARE(int, ip6_output_flowtable_size);
  122 #define V_ip6_output_flowtable_size     VNET(ip6_output_flowtable_size)
  123 #endif
  124 
  125 extern struct domain inet6domain;
  126 
  127 u_char ip6_protox[IPPROTO_MAX];
  128 VNET_DEFINE(struct in6_ifaddrhead, in6_ifaddrhead);
  129 
  130 static struct netisr_handler ip6_nh = {
  131         .nh_name = "ip6",
  132         .nh_handler = ip6_input,
  133         .nh_proto = NETISR_IPV6,
  134         .nh_policy = NETISR_POLICY_FLOW,
  135 };
  136 
  137 VNET_DECLARE(struct callout, in6_tmpaddrtimer_ch);
  138 #define V_in6_tmpaddrtimer_ch           VNET(in6_tmpaddrtimer_ch)
  139 
  140 VNET_DEFINE(struct pfil_head, inet6_pfil_hook);
  141 
  142 VNET_DEFINE(struct ip6stat, ip6stat);
  143 
  144 struct rwlock in6_ifaddr_lock;
  145 RW_SYSINIT(in6_ifaddr_lock, &in6_ifaddr_lock, "in6_ifaddr_lock");
  146 
  147 static void ip6_init2(void *);
  148 static struct ip6aux *ip6_setdstifaddr(struct mbuf *, struct in6_ifaddr *);
  149 static struct ip6aux *ip6_addaux(struct mbuf *);
  150 static struct ip6aux *ip6_findaux(struct mbuf *m);
  151 static void ip6_delaux (struct mbuf *);
  152 static int ip6_hopopts_input(u_int32_t *, u_int32_t *, struct mbuf **, int *);
  153 #ifdef PULLDOWN_TEST
  154 static struct mbuf *ip6_pullexthdr(struct mbuf *, size_t, int);
  155 #endif
  156 
  157 /*
  158  * IP6 initialization: fill in IP6 protocol switch table.
  159  * All protocols not implemented in kernel go to raw IP6 protocol handler.
  160  */
  161 void
  162 ip6_init(void)
  163 {
  164         struct ip6protosw *pr;
  165         int i;
  166 
  167         TUNABLE_INT_FETCH("net.inet6.ip6.auto_linklocal",
  168             &V_ip6_auto_linklocal);
  169         TUNABLE_INT_FETCH("net.inet6.ip6.accept_rtadv", &V_ip6_accept_rtadv);
  170         TUNABLE_INT_FETCH("net.inet6.ip6.no_radr", &V_ip6_no_radr);
  171 
  172         TAILQ_INIT(&V_in6_ifaddrhead);
  173 
  174         /* Initialize packet filter hooks. */
  175         V_inet6_pfil_hook.ph_type = PFIL_TYPE_AF;
  176         V_inet6_pfil_hook.ph_af = AF_INET6;
  177         if ((i = pfil_head_register(&V_inet6_pfil_hook)) != 0)
  178                 printf("%s: WARNING: unable to register pfil hook, "
  179                         "error %d\n", __func__, i);
  180 
  181         scope6_init();
  182         addrsel_policy_init();
  183         nd6_init();
  184         frag6_init();
  185 
  186 #ifdef FLOWTABLE
  187         if (TUNABLE_INT_FETCH("net.inet6.ip6.output_flowtable_size",
  188                 &V_ip6_output_flowtable_size)) {
  189                 if (V_ip6_output_flowtable_size < 256)
  190                         V_ip6_output_flowtable_size = 256;
  191                 if (!powerof2(V_ip6_output_flowtable_size)) {
  192                         printf("flowtable must be power of 2 size\n");
  193                         V_ip6_output_flowtable_size = 2048;
  194                 }
  195         } else {
  196                 /*
  197                  * round up to the next power of 2
  198                  */
  199                 V_ip6_output_flowtable_size = 1 << fls((1024 + maxusers * 64)-1);
  200         }
  201         V_ip6_ft = flowtable_alloc("ipv6", V_ip6_output_flowtable_size, FL_IPV6|FL_PCPU);
  202 #endif  
  203         
  204         V_ip6_desync_factor = arc4random() % MAX_TEMP_DESYNC_FACTOR;
  205 
  206         /* Skip global initialization stuff for non-default instances. */
  207         if (!IS_DEFAULT_VNET(curvnet))
  208                 return;
  209 
  210 #ifdef DIAGNOSTIC
  211         if (sizeof(struct protosw) != sizeof(struct ip6protosw))
  212                 panic("sizeof(protosw) != sizeof(ip6protosw)");
  213 #endif
  214         pr = (struct ip6protosw *)pffindproto(PF_INET6, IPPROTO_RAW, SOCK_RAW);
  215         if (pr == NULL)
  216                 panic("ip6_init");
  217 
  218         /* Initialize the entire ip6_protox[] array to IPPROTO_RAW. */
  219         for (i = 0; i < IPPROTO_MAX; i++)
  220                 ip6_protox[i] = pr - inet6sw;
  221         /*
  222          * Cycle through IP protocols and put them into the appropriate place
  223          * in ip6_protox[].
  224          */
  225         for (pr = (struct ip6protosw *)inet6domain.dom_protosw;
  226             pr < (struct ip6protosw *)inet6domain.dom_protoswNPROTOSW; pr++)
  227                 if (pr->pr_domain->dom_family == PF_INET6 &&
  228                     pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) {
  229                         /* Be careful to only index valid IP protocols. */
  230                         if (pr->pr_protocol < IPPROTO_MAX)
  231                                 ip6_protox[pr->pr_protocol] = pr - inet6sw;
  232                 }
  233 
  234         netisr_register(&ip6_nh);
  235 }
  236 
  237 /*
  238  * The protocol to be inserted into ip6_protox[] must be already registered
  239  * in inet6sw[], either statically or through pf_proto_register().
  240  */
  241 int
  242 ip6proto_register(short ip6proto)
  243 {
  244         struct ip6protosw *pr;
  245 
  246         /* Sanity checks. */
  247         if (ip6proto <= 0 || ip6proto >= IPPROTO_MAX)
  248                 return (EPROTONOSUPPORT);
  249 
  250         /*
  251          * The protocol slot must not be occupied by another protocol
  252          * already.  An index pointing to IPPROTO_RAW is unused.
  253          */
  254         pr = (struct ip6protosw *)pffindproto(PF_INET6, IPPROTO_RAW, SOCK_RAW);
  255         if (pr == NULL)
  256                 return (EPFNOSUPPORT);
  257         if (ip6_protox[ip6proto] != pr - inet6sw)       /* IPPROTO_RAW */
  258                 return (EEXIST);
  259 
  260         /*
  261          * Find the protocol position in inet6sw[] and set the index.
  262          */
  263         for (pr = (struct ip6protosw *)inet6domain.dom_protosw;
  264             pr < (struct ip6protosw *)inet6domain.dom_protoswNPROTOSW; pr++) {
  265                 if (pr->pr_domain->dom_family == PF_INET6 &&
  266                     pr->pr_protocol && pr->pr_protocol == ip6proto) {
  267                         ip6_protox[pr->pr_protocol] = pr - inet6sw;
  268                         return (0);
  269                 }
  270         }
  271         return (EPROTONOSUPPORT);
  272 }
  273 
  274 int
  275 ip6proto_unregister(short ip6proto)
  276 {
  277         struct ip6protosw *pr;
  278 
  279         /* Sanity checks. */
  280         if (ip6proto <= 0 || ip6proto >= IPPROTO_MAX)
  281                 return (EPROTONOSUPPORT);
  282 
  283         /* Check if the protocol was indeed registered. */
  284         pr = (struct ip6protosw *)pffindproto(PF_INET6, IPPROTO_RAW, SOCK_RAW);
  285         if (pr == NULL)
  286                 return (EPFNOSUPPORT);
  287         if (ip6_protox[ip6proto] == pr - inet6sw)       /* IPPROTO_RAW */
  288                 return (ENOENT);
  289 
  290         /* Reset the protocol slot to IPPROTO_RAW. */
  291         ip6_protox[ip6proto] = pr - inet6sw;
  292         return (0);
  293 }
  294 
  295 #ifdef VIMAGE
  296 void
  297 ip6_destroy()
  298 {
  299 
  300         nd6_destroy();
  301         callout_drain(&V_in6_tmpaddrtimer_ch);
  302 }
  303 #endif
  304 
  305 static int
  306 ip6_init2_vnet(const void *unused __unused)
  307 {
  308 
  309         /* nd6_timer_init */
  310         callout_init(&V_nd6_timer_ch, 0);
  311         callout_reset(&V_nd6_timer_ch, hz, nd6_timer, curvnet);
  312 
  313         /* timer for regeneranation of temporary addresses randomize ID */
  314         callout_init(&V_in6_tmpaddrtimer_ch, 0);
  315         callout_reset(&V_in6_tmpaddrtimer_ch,
  316                       (V_ip6_temp_preferred_lifetime - V_ip6_desync_factor -
  317                        V_ip6_temp_regen_advance) * hz,
  318                       in6_tmpaddrtimer, curvnet);
  319 
  320         return (0);
  321 }
  322 
  323 static void
  324 ip6_init2(void *dummy)
  325 {
  326 
  327         ip6_init2_vnet(NULL);
  328 }
  329 
  330 /* cheat */
  331 /* This must be after route_init(), which is now SI_ORDER_THIRD */
  332 SYSINIT(netinet6init2, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, ip6_init2, NULL);
  333 
  334 static int
  335 ip6_input_hbh(struct mbuf *m, uint32_t *plen, uint32_t *rtalert, int *off,
  336     int *nxt, int *ours)
  337 {
  338         struct ip6_hdr *ip6;
  339         struct ip6_hbh *hbh;
  340 
  341         if (ip6_hopopts_input(plen, rtalert, &m, off)) {
  342 #if 0   /*touches NULL pointer*/
  343                 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
  344 #endif
  345                 goto out;       /* m have already been freed */
  346         }
  347 
  348         /* adjust pointer */
  349         ip6 = mtod(m, struct ip6_hdr *);
  350 
  351         /*
  352          * if the payload length field is 0 and the next header field
  353          * indicates Hop-by-Hop Options header, then a Jumbo Payload
  354          * option MUST be included.
  355          */
  356         if (ip6->ip6_plen == 0 && *plen == 0) {
  357                 /*
  358                  * Note that if a valid jumbo payload option is
  359                  * contained, ip6_hopopts_input() must set a valid
  360                  * (non-zero) payload length to the variable plen.
  361                  */
  362                 IP6STAT_INC(ip6s_badoptions);
  363                 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
  364                 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_hdrerr);
  365                 icmp6_error(m, ICMP6_PARAM_PROB,
  366                             ICMP6_PARAMPROB_HEADER,
  367                             (caddr_t)&ip6->ip6_plen - (caddr_t)ip6);
  368                 goto out;
  369         }
  370 #ifndef PULLDOWN_TEST
  371         /* ip6_hopopts_input() ensures that mbuf is contiguous */
  372         hbh = (struct ip6_hbh *)(ip6 + 1);
  373 #else
  374         IP6_EXTHDR_GET(hbh, struct ip6_hbh *, m, sizeof(struct ip6_hdr),
  375                 sizeof(struct ip6_hbh));
  376         if (hbh == NULL) {
  377                 IP6STAT_INC(ip6s_tooshort);
  378                 goto out;
  379         }
  380 #endif
  381         *nxt = hbh->ip6h_nxt;
  382 
  383         /*
  384          * If we are acting as a router and the packet contains a
  385          * router alert option, see if we know the option value.
  386          * Currently, we only support the option value for MLD, in which
  387          * case we should pass the packet to the multicast routing
  388          * daemon.
  389          */
  390         if (*rtalert != ~0) {
  391                 switch (*rtalert) {
  392                 case IP6OPT_RTALERT_MLD:
  393                         if (V_ip6_forwarding)
  394                                 *ours = 1;
  395                         break;
  396                 default:
  397                         /*
  398                          * RFC2711 requires unrecognized values must be
  399                          * silently ignored.
  400                          */
  401                         break;
  402                 }
  403         }
  404 
  405         return (0);
  406 
  407 out:
  408         return (1);
  409 }
  410 
  411 void
  412 ip6_input(struct mbuf *m)
  413 {
  414         struct ip6_hdr *ip6;
  415         int off = sizeof(struct ip6_hdr), nest;
  416         u_int32_t plen;
  417         u_int32_t rtalert = ~0;
  418         int nxt, ours = 0;
  419         struct ifnet *deliverifp = NULL, *ifp = NULL;
  420         struct in6_addr odst;
  421         struct route_in6 rin6;
  422         int srcrt = 0;
  423         struct llentry *lle = NULL;
  424         struct sockaddr_in6 dst6, *dst;
  425 
  426         bzero(&rin6, sizeof(struct route_in6));
  427 #ifdef IPSEC
  428         /*
  429          * should the inner packet be considered authentic?
  430          * see comment in ah4_input().
  431          * NB: m cannot be NULL when passed to the input routine
  432          */
  433 
  434         m->m_flags &= ~M_AUTHIPHDR;
  435         m->m_flags &= ~M_AUTHIPDGM;
  436 
  437 #endif /* IPSEC */
  438 
  439         /*
  440          * make sure we don't have onion peering information into m_tag.
  441          */
  442         ip6_delaux(m);
  443 
  444         if (m->m_flags & M_FASTFWD_OURS) {
  445                 /*
  446                  * Firewall changed destination to local.
  447                  */
  448                 m->m_flags &= ~M_FASTFWD_OURS;
  449                 ours = 1;
  450                 deliverifp = m->m_pkthdr.rcvif;
  451                 ip6 = mtod(m, struct ip6_hdr *);
  452                 goto hbhcheck;
  453         }
  454 
  455         /*
  456          * mbuf statistics
  457          */
  458         if (m->m_flags & M_EXT) {
  459                 if (m->m_next)
  460                         IP6STAT_INC(ip6s_mext2m);
  461                 else
  462                         IP6STAT_INC(ip6s_mext1);
  463         } else {
  464                 if (m->m_next) {
  465                         if (m->m_flags & M_LOOP) {
  466                                 IP6STAT_INC(ip6s_m2m[V_loif->if_index]);
  467                         } else if (m->m_pkthdr.rcvif->if_index < IP6S_M2MMAX)
  468                                 IP6STAT_INC(
  469                                     ip6s_m2m[m->m_pkthdr.rcvif->if_index]);
  470                         else
  471                                 IP6STAT_INC(ip6s_m2m[0]);
  472                 } else
  473                         IP6STAT_INC(ip6s_m1);
  474         }
  475 
  476         /* drop the packet if IPv6 operation is disabled on the IF */
  477         if ((ND_IFINFO(m->m_pkthdr.rcvif)->flags & ND6_IFF_IFDISABLED)) {
  478                 m_freem(m);
  479                 return;
  480         }
  481 
  482         in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_receive);
  483         IP6STAT_INC(ip6s_total);
  484 
  485 #ifndef PULLDOWN_TEST
  486         /*
  487          * L2 bridge code and some other code can return mbuf chain
  488          * that does not conform to KAME requirement.  too bad.
  489          * XXX: fails to join if interface MTU > MCLBYTES.  jumbogram?
  490          */
  491         if (m && m->m_next != NULL && m->m_pkthdr.len < MCLBYTES) {
  492                 struct mbuf *n;
  493 
  494                 MGETHDR(n, M_DONTWAIT, MT_HEADER);
  495                 if (n)
  496                         M_MOVE_PKTHDR(n, m);
  497                 if (n && n->m_pkthdr.len > MHLEN) {
  498                         MCLGET(n, M_DONTWAIT);
  499                         if ((n->m_flags & M_EXT) == 0) {
  500                                 m_freem(n);
  501                                 n = NULL;
  502                         }
  503                 }
  504                 if (n == NULL) {
  505                         m_freem(m);
  506                         return; /* ENOBUFS */
  507                 }
  508 
  509                 m_copydata(m, 0, n->m_pkthdr.len, mtod(n, caddr_t));
  510                 n->m_len = n->m_pkthdr.len;
  511                 m_freem(m);
  512                 m = n;
  513         }
  514         IP6_EXTHDR_CHECK(m, 0, sizeof(struct ip6_hdr), /* nothing */);
  515 #endif
  516 
  517         if (m->m_len < sizeof(struct ip6_hdr)) {
  518                 struct ifnet *inifp;
  519                 inifp = m->m_pkthdr.rcvif;
  520                 if ((m = m_pullup(m, sizeof(struct ip6_hdr))) == NULL) {
  521                         IP6STAT_INC(ip6s_toosmall);
  522                         in6_ifstat_inc(inifp, ifs6_in_hdrerr);
  523                         return;
  524                 }
  525         }
  526 
  527         ip6 = mtod(m, struct ip6_hdr *);
  528 
  529         if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) {
  530                 IP6STAT_INC(ip6s_badvers);
  531                 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_hdrerr);
  532                 goto bad;
  533         }
  534 
  535         IP6STAT_INC(ip6s_nxthist[ip6->ip6_nxt]);
  536 
  537         /*
  538          * Check against address spoofing/corruption.
  539          */
  540         if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_src) ||
  541             IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_dst)) {
  542                 /*
  543                  * XXX: "badscope" is not very suitable for a multicast source.
  544                  */
  545                 IP6STAT_INC(ip6s_badscope);
  546                 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
  547                 goto bad;
  548         }
  549         if (IN6_IS_ADDR_MC_INTFACELOCAL(&ip6->ip6_dst) &&
  550             !(m->m_flags & M_LOOP)) {
  551                 /*
  552                  * In this case, the packet should come from the loopback
  553                  * interface.  However, we cannot just check the if_flags,
  554                  * because ip6_mloopback() passes the "actual" interface
  555                  * as the outgoing/incoming interface.
  556                  */
  557                 IP6STAT_INC(ip6s_badscope);
  558                 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
  559                 goto bad;
  560         }
  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 
  647 passin:
  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;
 1022 bad:
 1023         m_freem(m);
 1024 out:
 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  */
 1038 static struct ip6aux *
 1039 ip6_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 
 1049 struct in6_ifaddr *
 1050 ip6_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  */
 1070 static int
 1071 ip6_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         u_int8_t *opt;
 1078 
 1079         /* validation of the length of the header */
 1080 #ifndef PULLDOWN_TEST
 1081         IP6_EXTHDR_CHECK(m, off, sizeof(*hbh), -1);
 1082         hbh = (struct ip6_hbh *)(mtod(m, caddr_t) + off);
 1083         hbhlen = (hbh->ip6h_len + 1) << 3;
 1084 
 1085         IP6_EXTHDR_CHECK(m, off, hbhlen, -1);
 1086         hbh = (struct ip6_hbh *)(mtod(m, caddr_t) + off);
 1087 #else
 1088         IP6_EXTHDR_GET(hbh, struct ip6_hbh *, m,
 1089                 sizeof(struct ip6_hdr), sizeof(struct ip6_hbh));
 1090         if (hbh == NULL) {
 1091                 IP6STAT_INC(ip6s_tooshort);
 1092                 return -1;
 1093         }
 1094         hbhlen = (hbh->ip6h_len + 1) << 3;
 1095         IP6_EXTHDR_GET(hbh, struct ip6_hbh *, m, sizeof(struct ip6_hdr),
 1096                 hbhlen);
 1097         if (hbh == NULL) {
 1098                 IP6STAT_INC(ip6s_tooshort);
 1099                 return -1;
 1100         }
 1101 #endif
 1102         off += hbhlen;
 1103         hbhlen -= sizeof(struct ip6_hbh);
 1104         opt = (u_int8_t *)hbh + sizeof(struct ip6_hbh);
 1105 
 1106         if (ip6_process_hopopts(m, (u_int8_t *)hbh + sizeof(struct ip6_hbh),
 1107                                 hbhlen, rtalertp, plenp) < 0)
 1108                 return (-1);
 1109 
 1110         *offp = off;
 1111         *mp = m;
 1112         return (0);
 1113 }
 1114 
 1115 /*
 1116  * Search header for all Hop-by-hop options and process each option.
 1117  * This function is separate from ip6_hopopts_input() in order to
 1118  * handle a case where the sending node itself process its hop-by-hop
 1119  * options header. In such a case, the function is called from ip6_output().
 1120  *
 1121  * The function assumes that hbh header is located right after the IPv6 header
 1122  * (RFC2460 p7), opthead is pointer into data content in m, and opthead to
 1123  * opthead + hbhlen is located in contiguous memory region.
 1124  */
 1125 int
 1126 ip6_process_hopopts(struct mbuf *m, u_int8_t *opthead, int hbhlen,
 1127     u_int32_t *rtalertp, u_int32_t *plenp)
 1128 {
 1129         struct ip6_hdr *ip6;
 1130         int optlen = 0;
 1131         u_int8_t *opt = opthead;
 1132         u_int16_t rtalert_val;
 1133         u_int32_t jumboplen;
 1134         const int erroff = sizeof(struct ip6_hdr) + sizeof(struct ip6_hbh);
 1135 
 1136         for (; hbhlen > 0; hbhlen -= optlen, opt += optlen) {
 1137                 switch (*opt) {
 1138                 case IP6OPT_PAD1:
 1139                         optlen = 1;
 1140                         break;
 1141                 case IP6OPT_PADN:
 1142                         if (hbhlen < IP6OPT_MINLEN) {
 1143                                 IP6STAT_INC(ip6s_toosmall);
 1144                                 goto bad;
 1145                         }
 1146                         optlen = *(opt + 1) + 2;
 1147                         break;
 1148                 case IP6OPT_ROUTER_ALERT:
 1149                         /* XXX may need check for alignment */
 1150                         if (hbhlen < IP6OPT_RTALERT_LEN) {
 1151                                 IP6STAT_INC(ip6s_toosmall);
 1152                                 goto bad;
 1153                         }
 1154                         if (*(opt + 1) != IP6OPT_RTALERT_LEN - 2) {
 1155                                 /* XXX stat */
 1156                                 icmp6_error(m, ICMP6_PARAM_PROB,
 1157                                     ICMP6_PARAMPROB_HEADER,
 1158                                     erroff + opt + 1 - opthead);
 1159                                 return (-1);
 1160                         }
 1161                         optlen = IP6OPT_RTALERT_LEN;
 1162                         bcopy((caddr_t)(opt + 2), (caddr_t)&rtalert_val, 2);
 1163                         *rtalertp = ntohs(rtalert_val);
 1164                         break;
 1165                 case IP6OPT_JUMBO:
 1166                         /* XXX may need check for alignment */
 1167                         if (hbhlen < IP6OPT_JUMBO_LEN) {
 1168                                 IP6STAT_INC(ip6s_toosmall);
 1169                                 goto bad;
 1170                         }
 1171                         if (*(opt + 1) != IP6OPT_JUMBO_LEN - 2) {
 1172                                 /* XXX stat */
 1173                                 icmp6_error(m, ICMP6_PARAM_PROB,
 1174                                     ICMP6_PARAMPROB_HEADER,
 1175                                     erroff + opt + 1 - opthead);
 1176                                 return (-1);
 1177                         }
 1178                         optlen = IP6OPT_JUMBO_LEN;
 1179 
 1180                         /*
 1181                          * IPv6 packets that have non 0 payload length
 1182                          * must not contain a jumbo payload option.
 1183                          */
 1184                         ip6 = mtod(m, struct ip6_hdr *);
 1185                         if (ip6->ip6_plen) {
 1186                                 IP6STAT_INC(ip6s_badoptions);
 1187                                 icmp6_error(m, ICMP6_PARAM_PROB,
 1188                                     ICMP6_PARAMPROB_HEADER,
 1189                                     erroff + opt - opthead);
 1190                                 return (-1);
 1191                         }
 1192 
 1193                         /*
 1194                          * We may see jumbolen in unaligned location, so
 1195                          * we'd need to perform bcopy().
 1196                          */
 1197                         bcopy(opt + 2, &jumboplen, sizeof(jumboplen));
 1198                         jumboplen = (u_int32_t)htonl(jumboplen);
 1199 
 1200 #if 1
 1201                         /*
 1202                          * if there are multiple jumbo payload options,
 1203                          * *plenp will be non-zero and the packet will be
 1204                          * rejected.
 1205                          * the behavior may need some debate in ipngwg -
 1206                          * multiple options does not make sense, however,
 1207                          * there's no explicit mention in specification.
 1208                          */
 1209                         if (*plenp != 0) {
 1210                                 IP6STAT_INC(ip6s_badoptions);
 1211                                 icmp6_error(m, ICMP6_PARAM_PROB,
 1212                                     ICMP6_PARAMPROB_HEADER,
 1213                                     erroff + opt + 2 - opthead);
 1214                                 return (-1);
 1215                         }
 1216 #endif
 1217 
 1218                         /*
 1219                          * jumbo payload length must be larger than 65535.
 1220                          */
 1221                         if (jumboplen <= IPV6_MAXPACKET) {
 1222                                 IP6STAT_INC(ip6s_badoptions);
 1223                                 icmp6_error(m, ICMP6_PARAM_PROB,
 1224                                     ICMP6_PARAMPROB_HEADER,
 1225                                     erroff + opt + 2 - opthead);
 1226                                 return (-1);
 1227                         }
 1228                         *plenp = jumboplen;
 1229 
 1230                         break;
 1231                 default:                /* unknown option */
 1232                         if (hbhlen < IP6OPT_MINLEN) {
 1233                                 IP6STAT_INC(ip6s_toosmall);
 1234                                 goto bad;
 1235                         }
 1236                         optlen = ip6_unknown_opt(opt, m,
 1237                             erroff + opt - opthead);
 1238                         if (optlen == -1)
 1239                                 return (-1);
 1240                         optlen += 2;
 1241                         break;
 1242                 }
 1243         }
 1244 
 1245         return (0);
 1246 
 1247   bad:
 1248         m_freem(m);
 1249         return (-1);
 1250 }
 1251 
 1252 /*
 1253  * Unknown option processing.
 1254  * The third argument `off' is the offset from the IPv6 header to the option,
 1255  * which is necessary if the IPv6 header the and option header and IPv6 header
 1256  * is not contiguous in order to return an ICMPv6 error.
 1257  */
 1258 int
 1259 ip6_unknown_opt(u_int8_t *optp, struct mbuf *m, int off)
 1260 {
 1261         struct ip6_hdr *ip6;
 1262 
 1263         switch (IP6OPT_TYPE(*optp)) {
 1264         case IP6OPT_TYPE_SKIP: /* ignore the option */
 1265                 return ((int)*(optp + 1));
 1266         case IP6OPT_TYPE_DISCARD:       /* silently discard */
 1267                 m_freem(m);
 1268                 return (-1);
 1269         case IP6OPT_TYPE_FORCEICMP: /* send ICMP even if multicasted */
 1270                 IP6STAT_INC(ip6s_badoptions);
 1271                 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_OPTION, off);
 1272                 return (-1);
 1273         case IP6OPT_TYPE_ICMP: /* send ICMP if not multicasted */
 1274                 IP6STAT_INC(ip6s_badoptions);
 1275                 ip6 = mtod(m, struct ip6_hdr *);
 1276                 if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) ||
 1277                     (m->m_flags & (M_BCAST|M_MCAST)))
 1278                         m_freem(m);
 1279                 else
 1280                         icmp6_error(m, ICMP6_PARAM_PROB,
 1281                                     ICMP6_PARAMPROB_OPTION, off);
 1282                 return (-1);
 1283         }
 1284 
 1285         m_freem(m);             /* XXX: NOTREACHED */
 1286         return (-1);
 1287 }
 1288 
 1289 /*
 1290  * Create the "control" list for this pcb.
 1291  * These functions will not modify mbuf chain at all.
 1292  *
 1293  * With KAME mbuf chain restriction:
 1294  * The routine will be called from upper layer handlers like tcp6_input().
 1295  * Thus the routine assumes that the caller (tcp6_input) have already
 1296  * called IP6_EXTHDR_CHECK() and all the extension headers are located in the
 1297  * very first mbuf on the mbuf chain.
 1298  *
 1299  * ip6_savecontrol_v4 will handle those options that are possible to be
 1300  * set on a v4-mapped socket.
 1301  * ip6_savecontrol will directly call ip6_savecontrol_v4 to handle those
 1302  * options and handle the v6-only ones itself.
 1303  */
 1304 struct mbuf **
 1305 ip6_savecontrol_v4(struct inpcb *inp, struct mbuf *m, struct mbuf **mp,
 1306     int *v4only)
 1307 {
 1308         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
 1309 
 1310 #ifdef SO_TIMESTAMP
 1311         if ((inp->inp_socket->so_options & SO_TIMESTAMP) != 0) {
 1312                 struct timeval tv;
 1313 
 1314                 microtime(&tv);
 1315                 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv),
 1316                     SCM_TIMESTAMP, SOL_SOCKET);
 1317                 if (*mp)
 1318                         mp = &(*mp)->m_next;
 1319         }
 1320 #endif
 1321 
 1322 #define IS2292(inp, x, y)       (((inp)->inp_flags & IN6P_RFC2292) ? (x) : (y))
 1323         /* RFC 2292 sec. 5 */
 1324         if ((inp->inp_flags & IN6P_PKTINFO) != 0) {
 1325                 struct in6_pktinfo pi6;
 1326 
 1327                 if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) {
 1328 #ifdef INET
 1329                         struct ip *ip;
 1330 
 1331                         ip = mtod(m, struct ip *);
 1332                         pi6.ipi6_addr.s6_addr32[0] = 0;
 1333                         pi6.ipi6_addr.s6_addr32[1] = 0;
 1334                         pi6.ipi6_addr.s6_addr32[2] = IPV6_ADDR_INT32_SMP;
 1335                         pi6.ipi6_addr.s6_addr32[3] = ip->ip_dst.s_addr;
 1336 #else
 1337                         /* We won't hit this code */
 1338                         bzero(&pi6.ipi6_addr, sizeof(struct in6_addr));
 1339 #endif
 1340                 } else {        
 1341                         bcopy(&ip6->ip6_dst, &pi6.ipi6_addr, sizeof(struct in6_addr));
 1342                         in6_clearscope(&pi6.ipi6_addr); /* XXX */
 1343                 }
 1344                 pi6.ipi6_ifindex =
 1345                     (m && m->m_pkthdr.rcvif) ? m->m_pkthdr.rcvif->if_index : 0;
 1346 
 1347                 *mp = sbcreatecontrol((caddr_t) &pi6,
 1348                     sizeof(struct in6_pktinfo),
 1349                     IS2292(inp, IPV6_2292PKTINFO, IPV6_PKTINFO), IPPROTO_IPV6);
 1350                 if (*mp)
 1351                         mp = &(*mp)->m_next;
 1352         }
 1353 
 1354         if ((inp->inp_flags & IN6P_HOPLIMIT) != 0) {
 1355                 int hlim;
 1356 
 1357                 if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) {
 1358 #ifdef INET
 1359                         struct ip *ip;
 1360 
 1361                         ip = mtod(m, struct ip *);
 1362                         hlim = ip->ip_ttl;
 1363 #else
 1364                         /* We won't hit this code */
 1365                         hlim = 0;
 1366 #endif
 1367                 } else {
 1368                         hlim = ip6->ip6_hlim & 0xff;
 1369                 }
 1370                 *mp = sbcreatecontrol((caddr_t) &hlim, sizeof(int),
 1371                     IS2292(inp, IPV6_2292HOPLIMIT, IPV6_HOPLIMIT),
 1372                     IPPROTO_IPV6);
 1373                 if (*mp)
 1374                         mp = &(*mp)->m_next;
 1375         }
 1376 
 1377         if ((inp->inp_flags & IN6P_TCLASS) != 0) {
 1378                 int tclass;
 1379 
 1380                 if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) {
 1381 #ifdef INET
 1382                         struct ip *ip;
 1383 
 1384                         ip = mtod(m, struct ip *);
 1385                         tclass = ip->ip_tos;
 1386 #else
 1387                         /* We won't hit this code */
 1388                         tclass = 0;
 1389 #endif
 1390                 } else {
 1391                         u_int32_t flowinfo;
 1392 
 1393                         flowinfo = (u_int32_t)ntohl(ip6->ip6_flow & IPV6_FLOWINFO_MASK);
 1394                         flowinfo >>= 20;
 1395                         tclass = flowinfo & 0xff;
 1396                 }
 1397                 *mp = sbcreatecontrol((caddr_t) &tclass, sizeof(int),
 1398                     IPV6_TCLASS, IPPROTO_IPV6);
 1399                 if (*mp)
 1400                         mp = &(*mp)->m_next;
 1401         }
 1402 
 1403         if (v4only != NULL) {
 1404                 if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) {
 1405                         *v4only = 1;
 1406                 } else {
 1407                         *v4only = 0;
 1408                 }
 1409         }
 1410 
 1411         return (mp);
 1412 }
 1413 
 1414 void
 1415 ip6_savecontrol(struct inpcb *in6p, struct mbuf *m, struct mbuf **mp)
 1416 {
 1417         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
 1418         int v4only = 0;
 1419 
 1420         mp = ip6_savecontrol_v4(in6p, m, mp, &v4only);
 1421         if (v4only)
 1422                 return;
 1423 
 1424         /*
 1425          * IPV6_HOPOPTS socket option.  Recall that we required super-user
 1426          * privilege for the option (see ip6_ctloutput), but it might be too
 1427          * strict, since there might be some hop-by-hop options which can be
 1428          * returned to normal user.
 1429          * See also RFC 2292 section 6 (or RFC 3542 section 8).
 1430          */
 1431         if ((in6p->inp_flags & IN6P_HOPOPTS) != 0) {
 1432                 /*
 1433                  * Check if a hop-by-hop options header is contatined in the
 1434                  * received packet, and if so, store the options as ancillary
 1435                  * data. Note that a hop-by-hop options header must be
 1436                  * just after the IPv6 header, which is assured through the
 1437                  * IPv6 input processing.
 1438                  */
 1439                 if (ip6->ip6_nxt == IPPROTO_HOPOPTS) {
 1440                         struct ip6_hbh *hbh;
 1441                         int hbhlen = 0;
 1442 #ifdef PULLDOWN_TEST
 1443                         struct mbuf *ext;
 1444 #endif
 1445 
 1446 #ifndef PULLDOWN_TEST
 1447                         hbh = (struct ip6_hbh *)(ip6 + 1);
 1448                         hbhlen = (hbh->ip6h_len + 1) << 3;
 1449 #else
 1450                         ext = ip6_pullexthdr(m, sizeof(struct ip6_hdr),
 1451                             ip6->ip6_nxt);
 1452                         if (ext == NULL) {
 1453                                 IP6STAT_INC(ip6s_tooshort);
 1454                                 return;
 1455                         }
 1456                         hbh = mtod(ext, struct ip6_hbh *);
 1457                         hbhlen = (hbh->ip6h_len + 1) << 3;
 1458                         if (hbhlen != ext->m_len) {
 1459                                 m_freem(ext);
 1460                                 IP6STAT_INC(ip6s_tooshort);
 1461                                 return;
 1462                         }
 1463 #endif
 1464 
 1465                         /*
 1466                          * XXX: We copy the whole header even if a
 1467                          * jumbo payload option is included, the option which
 1468                          * is to be removed before returning according to
 1469                          * RFC2292.
 1470                          * Note: this constraint is removed in RFC3542
 1471                          */
 1472                         *mp = sbcreatecontrol((caddr_t)hbh, hbhlen,
 1473                             IS2292(in6p, IPV6_2292HOPOPTS, IPV6_HOPOPTS),
 1474                             IPPROTO_IPV6);
 1475                         if (*mp)
 1476                                 mp = &(*mp)->m_next;
 1477 #ifdef PULLDOWN_TEST
 1478                         m_freem(ext);
 1479 #endif
 1480                 }
 1481         }
 1482 
 1483         if ((in6p->inp_flags & (IN6P_RTHDR | IN6P_DSTOPTS)) != 0) {
 1484                 int nxt = ip6->ip6_nxt, off = sizeof(struct ip6_hdr);
 1485 
 1486                 /*
 1487                  * Search for destination options headers or routing
 1488                  * header(s) through the header chain, and stores each
 1489                  * header as ancillary data.
 1490                  * Note that the order of the headers remains in
 1491                  * the chain of ancillary data.
 1492                  */
 1493                 while (1) {     /* is explicit loop prevention necessary? */
 1494                         struct ip6_ext *ip6e = NULL;
 1495                         int elen;
 1496 #ifdef PULLDOWN_TEST
 1497                         struct mbuf *ext = NULL;
 1498 #endif
 1499 
 1500                         /*
 1501                          * if it is not an extension header, don't try to
 1502                          * pull it from the chain.
 1503                          */
 1504                         switch (nxt) {
 1505                         case IPPROTO_DSTOPTS:
 1506                         case IPPROTO_ROUTING:
 1507                         case IPPROTO_HOPOPTS:
 1508                         case IPPROTO_AH: /* is it possible? */
 1509                                 break;
 1510                         default:
 1511                                 goto loopend;
 1512                         }
 1513 
 1514 #ifndef PULLDOWN_TEST
 1515                         if (off + sizeof(*ip6e) > m->m_len)
 1516                                 goto loopend;
 1517                         ip6e = (struct ip6_ext *)(mtod(m, caddr_t) + off);
 1518                         if (nxt == IPPROTO_AH)
 1519                                 elen = (ip6e->ip6e_len + 2) << 2;
 1520                         else
 1521                                 elen = (ip6e->ip6e_len + 1) << 3;
 1522                         if (off + elen > m->m_len)
 1523                                 goto loopend;
 1524 #else
 1525                         ext = ip6_pullexthdr(m, off, nxt);
 1526                         if (ext == NULL) {
 1527                                 IP6STAT_INC(ip6s_tooshort);
 1528                                 return;
 1529                         }
 1530                         ip6e = mtod(ext, struct ip6_ext *);
 1531                         if (nxt == IPPROTO_AH)
 1532                                 elen = (ip6e->ip6e_len + 2) << 2;
 1533                         else
 1534                                 elen = (ip6e->ip6e_len + 1) << 3;
 1535                         if (elen != ext->m_len) {
 1536                                 m_freem(ext);
 1537                                 IP6STAT_INC(ip6s_tooshort);
 1538                                 return;
 1539                         }
 1540 #endif
 1541 
 1542                         switch (nxt) {
 1543                         case IPPROTO_DSTOPTS:
 1544                                 if (!(in6p->inp_flags & IN6P_DSTOPTS))
 1545                                         break;
 1546 
 1547                                 *mp = sbcreatecontrol((caddr_t)ip6e, elen,
 1548                                     IS2292(in6p,
 1549                                         IPV6_2292DSTOPTS, IPV6_DSTOPTS),
 1550                                     IPPROTO_IPV6);
 1551                                 if (*mp)
 1552                                         mp = &(*mp)->m_next;
 1553                                 break;
 1554                         case IPPROTO_ROUTING:
 1555                                 if (!(in6p->inp_flags & IN6P_RTHDR))
 1556                                         break;
 1557 
 1558                                 *mp = sbcreatecontrol((caddr_t)ip6e, elen,
 1559                                     IS2292(in6p, IPV6_2292RTHDR, IPV6_RTHDR),
 1560                                     IPPROTO_IPV6);
 1561                                 if (*mp)
 1562                                         mp = &(*mp)->m_next;
 1563                                 break;
 1564                         case IPPROTO_HOPOPTS:
 1565                         case IPPROTO_AH: /* is it possible? */
 1566                                 break;
 1567 
 1568                         default:
 1569                                 /*
 1570                                  * other cases have been filtered in the above.
 1571                                  * none will visit this case.  here we supply
 1572                                  * the code just in case (nxt overwritten or
 1573                                  * other cases).
 1574                                  */
 1575 #ifdef PULLDOWN_TEST
 1576                                 m_freem(ext);
 1577 #endif
 1578                                 goto loopend;
 1579 
 1580                         }
 1581 
 1582                         /* proceed with the next header. */
 1583                         off += elen;
 1584                         nxt = ip6e->ip6e_nxt;
 1585                         ip6e = NULL;
 1586 #ifdef PULLDOWN_TEST
 1587                         m_freem(ext);
 1588                         ext = NULL;
 1589 #endif
 1590                 }
 1591           loopend:
 1592                 ;
 1593         }
 1594 }
 1595 #undef IS2292
 1596 
 1597 void
 1598 ip6_notify_pmtu(struct inpcb *in6p, struct sockaddr_in6 *dst, u_int32_t *mtu)
 1599 {
 1600         struct socket *so;
 1601         struct mbuf *m_mtu;
 1602         struct ip6_mtuinfo mtuctl;
 1603 
 1604         so =  in6p->inp_socket;
 1605 
 1606         if (mtu == NULL)
 1607                 return;
 1608 
 1609 #ifdef DIAGNOSTIC
 1610         if (so == NULL)         /* I believe this is impossible */
 1611                 panic("ip6_notify_pmtu: socket is NULL");
 1612 #endif
 1613 
 1614         bzero(&mtuctl, sizeof(mtuctl)); /* zero-clear for safety */
 1615         mtuctl.ip6m_mtu = *mtu;
 1616         mtuctl.ip6m_addr = *dst;
 1617         if (sa6_recoverscope(&mtuctl.ip6m_addr))
 1618                 return;
 1619 
 1620         if ((m_mtu = sbcreatecontrol((caddr_t)&mtuctl, sizeof(mtuctl),
 1621             IPV6_PATHMTU, IPPROTO_IPV6)) == NULL)
 1622                 return;
 1623 
 1624         if (sbappendaddr(&so->so_rcv, (struct sockaddr *)dst, NULL, m_mtu)
 1625             == 0) {
 1626                 m_freem(m_mtu);
 1627                 /* XXX: should count statistics */
 1628         } else
 1629                 sorwakeup(so);
 1630 
 1631         return;
 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  */
 1639 static struct mbuf *
 1640 ip6_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         MGET(n, M_DONTWAIT, MT_DATA);
 1665         if (n && elen >= MLEN) {
 1666                 MCLGET(n, M_DONTWAIT);
 1667                 if ((n->m_flags & M_EXT) == 0) {
 1668                         m_free(n);
 1669                         n = NULL;
 1670                 }
 1671         }
 1672         if (!n)
 1673                 return NULL;
 1674 
 1675         n->m_len = 0;
 1676         if (elen >= M_TRAILINGSPACE(n)) {
 1677                 m_free(n);
 1678                 return NULL;
 1679         }
 1680 
 1681         m_copydata(m, off, elen, mtod(n, caddr_t));
 1682         n->m_len = elen;
 1683         return n;
 1684 }
 1685 #endif
 1686 
 1687 /*
 1688  * Get pointer to the previous header followed by the header
 1689  * currently processed.
 1690  * XXX: This function supposes that
 1691  *      M includes all headers,
 1692  *      the next header field and the header length field of each header
 1693  *      are valid, and
 1694  *      the sum of each header length equals to OFF.
 1695  * Because of these assumptions, this function must be called very
 1696  * carefully. Moreover, it will not be used in the near future when
 1697  * we develop `neater' mechanism to process extension headers.
 1698  */
 1699 char *
 1700 ip6_get_prevhdr(struct mbuf *m, int off)
 1701 {
 1702         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
 1703 
 1704         if (off == sizeof(struct ip6_hdr))
 1705                 return (&ip6->ip6_nxt);
 1706         else {
 1707                 int len, nxt;
 1708                 struct ip6_ext *ip6e = NULL;
 1709 
 1710                 nxt = ip6->ip6_nxt;
 1711                 len = sizeof(struct ip6_hdr);
 1712                 while (len < off) {
 1713                         ip6e = (struct ip6_ext *)(mtod(m, caddr_t) + len);
 1714 
 1715                         switch (nxt) {
 1716                         case IPPROTO_FRAGMENT:
 1717                                 len += sizeof(struct ip6_frag);
 1718                                 break;
 1719                         case IPPROTO_AH:
 1720                                 len += (ip6e->ip6e_len + 2) << 2;
 1721                                 break;
 1722                         default:
 1723                                 len += (ip6e->ip6e_len + 1) << 3;
 1724                                 break;
 1725                         }
 1726                         nxt = ip6e->ip6e_nxt;
 1727                 }
 1728                 if (ip6e)
 1729                         return (&ip6e->ip6e_nxt);
 1730                 else
 1731                         return NULL;
 1732         }
 1733 }
 1734 
 1735 /*
 1736  * get next header offset.  m will be retained.
 1737  */
 1738 int
 1739 ip6_nexthdr(struct mbuf *m, int off, int proto, int *nxtp)
 1740 {
 1741         struct ip6_hdr ip6;
 1742         struct ip6_ext ip6e;
 1743         struct ip6_frag fh;
 1744 
 1745         /* just in case */
 1746         if (m == NULL)
 1747                 panic("ip6_nexthdr: m == NULL");
 1748         if ((m->m_flags & M_PKTHDR) == 0 || m->m_pkthdr.len < off)
 1749                 return -1;
 1750 
 1751         switch (proto) {
 1752         case IPPROTO_IPV6:
 1753                 if (m->m_pkthdr.len < off + sizeof(ip6))
 1754                         return -1;
 1755                 m_copydata(m, off, sizeof(ip6), (caddr_t)&ip6);
 1756                 if (nxtp)
 1757                         *nxtp = ip6.ip6_nxt;
 1758                 off += sizeof(ip6);
 1759                 return off;
 1760 
 1761         case IPPROTO_FRAGMENT:
 1762                 /*
 1763                  * terminate parsing if it is not the first fragment,
 1764                  * it does not make sense to parse through it.
 1765                  */
 1766                 if (m->m_pkthdr.len < off + sizeof(fh))
 1767                         return -1;
 1768                 m_copydata(m, off, sizeof(fh), (caddr_t)&fh);
 1769                 /* IP6F_OFF_MASK = 0xfff8(BigEndian), 0xf8ff(LittleEndian) */
 1770                 if (fh.ip6f_offlg & IP6F_OFF_MASK)
 1771                         return -1;
 1772                 if (nxtp)
 1773                         *nxtp = fh.ip6f_nxt;
 1774                 off += sizeof(struct ip6_frag);
 1775                 return off;
 1776 
 1777         case IPPROTO_AH:
 1778                 if (m->m_pkthdr.len < off + sizeof(ip6e))
 1779                         return -1;
 1780                 m_copydata(m, off, sizeof(ip6e), (caddr_t)&ip6e);
 1781                 if (nxtp)
 1782                         *nxtp = ip6e.ip6e_nxt;
 1783                 off += (ip6e.ip6e_len + 2) << 2;
 1784                 return off;
 1785 
 1786         case IPPROTO_HOPOPTS:
 1787         case IPPROTO_ROUTING:
 1788         case IPPROTO_DSTOPTS:
 1789                 if (m->m_pkthdr.len < off + sizeof(ip6e))
 1790                         return -1;
 1791                 m_copydata(m, off, sizeof(ip6e), (caddr_t)&ip6e);
 1792                 if (nxtp)
 1793                         *nxtp = ip6e.ip6e_nxt;
 1794                 off += (ip6e.ip6e_len + 1) << 3;
 1795                 return off;
 1796 
 1797         case IPPROTO_NONE:
 1798         case IPPROTO_ESP:
 1799         case IPPROTO_IPCOMP:
 1800                 /* give up */
 1801                 return -1;
 1802 
 1803         default:
 1804                 return -1;
 1805         }
 1806 
 1807         return -1;
 1808 }
 1809 
 1810 /*
 1811  * get offset for the last header in the chain.  m will be kept untainted.
 1812  */
 1813 int
 1814 ip6_lasthdr(struct mbuf *m, int off, int proto, int *nxtp)
 1815 {
 1816         int newoff;
 1817         int nxt;
 1818 
 1819         if (!nxtp) {
 1820                 nxt = -1;
 1821                 nxtp = &nxt;
 1822         }
 1823         while (1) {
 1824                 newoff = ip6_nexthdr(m, off, proto, nxtp);
 1825                 if (newoff < 0)
 1826                         return off;
 1827                 else if (newoff < off)
 1828                         return -1;      /* invalid */
 1829                 else if (newoff == off)
 1830                         return newoff;
 1831 
 1832                 off = newoff;
 1833                 proto = *nxtp;
 1834         }
 1835 }
 1836 
 1837 static struct ip6aux *
 1838 ip6_addaux(struct mbuf *m)
 1839 {
 1840         struct m_tag *mtag;
 1841 
 1842         mtag = m_tag_find(m, PACKET_TAG_IPV6_INPUT, NULL);
 1843         if (!mtag) {
 1844                 mtag = m_tag_get(PACKET_TAG_IPV6_INPUT, sizeof(struct ip6aux),
 1845                     M_NOWAIT);
 1846                 if (mtag) {
 1847                         m_tag_prepend(m, mtag);
 1848                         bzero(mtag + 1, sizeof(struct ip6aux));
 1849                 }
 1850         }
 1851         return mtag ? (struct ip6aux *)(mtag + 1) : NULL;
 1852 }
 1853 
 1854 static struct ip6aux *
 1855 ip6_findaux(struct mbuf *m)
 1856 {
 1857         struct m_tag *mtag;
 1858 
 1859         mtag = m_tag_find(m, PACKET_TAG_IPV6_INPUT, NULL);
 1860         return mtag ? (struct ip6aux *)(mtag + 1) : NULL;
 1861 }
 1862 
 1863 static void
 1864 ip6_delaux(struct mbuf *m)
 1865 {
 1866         struct m_tag *mtag;
 1867 
 1868         mtag = m_tag_find(m, PACKET_TAG_IPV6_INPUT, NULL);
 1869         if (mtag)
 1870                 m_tag_delete(m, mtag);
 1871 }
 1872 
 1873 /*
 1874  * System control for IP6
 1875  */
 1876 
 1877 u_char  inet6ctlerrmap[PRC_NCMDS] = {
 1878         0,              0,              0,              0,
 1879         0,              EMSGSIZE,       EHOSTDOWN,      EHOSTUNREACH,
 1880         EHOSTUNREACH,   EHOSTUNREACH,   ECONNREFUSED,   ECONNREFUSED,
 1881         EMSGSIZE,       EHOSTUNREACH,   0,              0,
 1882         0,              0,              0,              0,
 1883         ENOPROTOOPT
 1884 };

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