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("$FreeBSD$");
   65 
   66 #include "opt_inet.h"
   67 #include "opt_inet6.h"
   68 #include "opt_ipsec.h"
   69 
   70 #include <sys/param.h>
   71 #include <sys/systm.h>
   72 #include <sys/malloc.h>
   73 #include <sys/mbuf.h>
   74 #include <sys/proc.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>
   80 #include <sys/time.h>
   81 #include <sys/kernel.h>
   82 #include <sys/syslog.h>
   83 
   84 #include <net/if.h>
   85 #include <net/if_types.h>
   86 #include <net/if_dl.h>
   87 #include <net/route.h>
   88 #include <net/netisr.h>
   89 #include <net/pfil.h>
   90 
   91 #include <netinet/in.h>
   92 #include <netinet/in_systm.h>
   93 #ifdef INET
   94 #include <netinet/ip.h>
   95 #include <netinet/ip_icmp.h>
   96 #endif /* INET */
   97 #include <netinet/ip6.h>
   98 #include <netinet6/in6_var.h>
   99 #include <netinet6/ip6_var.h>
  100 #include <netinet/in_pcb.h>
  101 #include <netinet/icmp6.h>
  102 #include <netinet6/scope6_var.h>
  103 #include <netinet6/in6_ifattach.h>
  104 #include <netinet6/nd6.h>
  105 
  106 #ifdef IPSEC
  107 #include <netipsec/ipsec.h>
  108 #include <netinet6/ip6_ipsec.h>
  109 #include <netipsec/ipsec6.h>
  110 #endif /* IPSEC */
  111 
  112 #include <netinet6/ip6protosw.h>
  113 
  114 extern struct domain inet6domain;
  115 
  116 u_char ip6_protox[IPPROTO_MAX];
  117 static struct ifqueue ip6intrq;
  118 static int ip6qmaxlen = IFQ_MAXLEN;
  119 struct in6_ifaddr *in6_ifaddr;
  120 
  121 extern struct callout in6_tmpaddrtimer_ch;
  122 
  123 int ip6_forward_srcrt;                  /* XXX */
  124 int ip6_sourcecheck;                    /* XXX */
  125 int ip6_sourcecheck_interval;           /* XXX */
  126 
  127 int ip6_ours_check_algorithm;
  128 
  129 struct pfil_head inet6_pfil_hook;
  130 
  131 struct ip6stat ip6stat;
  132 
  133 static void ip6_init2(void *);
  134 static struct ip6aux *ip6_setdstifaddr(struct mbuf *, struct in6_ifaddr *);
  135 static int ip6_hopopts_input(u_int32_t *, u_int32_t *, struct mbuf **, int *);
  136 #ifdef PULLDOWN_TEST
  137 static struct mbuf *ip6_pullexthdr(struct mbuf *, size_t, int);
  138 #endif
  139 
  140 /*
  141  * IP6 initialization: fill in IP6 protocol switch table.
  142  * All protocols not implemented in kernel go to raw IP6 protocol handler.
  143  */
  144 void
  145 ip6_init(void)
  146 {
  147         struct ip6protosw *pr;
  148         int i;
  149 
  150 #ifdef DIAGNOSTIC
  151         if (sizeof(struct protosw) != sizeof(struct ip6protosw))
  152                 panic("sizeof(protosw) != sizeof(ip6protosw)");
  153 #endif
  154         pr = (struct ip6protosw *)pffindproto(PF_INET6, IPPROTO_RAW, SOCK_RAW);
  155         if (pr == 0)
  156                 panic("ip6_init");
  157 
  158         /* Initialize the entire ip6_protox[] array to IPPROTO_RAW. */
  159         for (i = 0; i < IPPROTO_MAX; i++)
  160                 ip6_protox[i] = pr - inet6sw;
  161         /*
  162          * Cycle through IP protocols and put them into the appropriate place
  163          * in ip6_protox[].
  164          */
  165         for (pr = (struct ip6protosw *)inet6domain.dom_protosw;
  166             pr < (struct ip6protosw *)inet6domain.dom_protoswNPROTOSW; pr++)
  167                 if (pr->pr_domain->dom_family == PF_INET6 &&
  168                     pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) {
  169                         /* Be careful to only index valid IP protocols. */
  170                         if (pr->pr_protocol < IPPROTO_MAX)
  171                                 ip6_protox[pr->pr_protocol] = pr - inet6sw;
  172                 }
  173 
  174         /* Initialize packet filter hooks. */
  175         inet6_pfil_hook.ph_type = PFIL_TYPE_AF;
  176         inet6_pfil_hook.ph_af = AF_INET6;
  177         if ((i = pfil_head_register(&inet6_pfil_hook)) != 0)
  178                 printf("%s: WARNING: unable to register pfil hook, "
  179                         "error %d\n", __func__, i);
  180 
  181         ip6intrq.ifq_maxlen = ip6qmaxlen;
  182         mtx_init(&ip6intrq.ifq_mtx, "ip6_inq", NULL, MTX_DEF);
  183         netisr_register(NETISR_IPV6, ip6_input, &ip6intrq, 0);
  184         scope6_init();
  185         addrsel_policy_init();
  186         nd6_init();
  187         frag6_init();
  188         ip6_desync_factor = arc4random() % MAX_TEMP_DESYNC_FACTOR;
  189 }
  190 
  191 static void
  192 ip6_init2(void *dummy)
  193 {
  194 
  195         /* nd6_timer_init */
  196         callout_init(&nd6_timer_ch, 0);
  197         callout_reset(&nd6_timer_ch, hz, nd6_timer, NULL);
  198 
  199         /* timer for regeneranation of temporary addresses randomize ID */
  200         callout_init(&in6_tmpaddrtimer_ch, 0);
  201         callout_reset(&in6_tmpaddrtimer_ch,
  202                       (ip6_temp_preferred_lifetime - ip6_desync_factor -
  203                        ip6_temp_regen_advance) * hz,
  204                       in6_tmpaddrtimer, NULL);
  205 }
  206 
  207 /* cheat */
  208 /* This must be after route_init(), which is now SI_ORDER_THIRD */
  209 SYSINIT(netinet6init2, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, ip6_init2, NULL);
  210 
  211 extern struct   route_in6 ip6_forward_rt;
  212 
  213 void
  214 ip6_input(struct mbuf *m)
  215 {
  216         struct ip6_hdr *ip6;
  217         int off = sizeof(struct ip6_hdr), nest;
  218         u_int32_t plen;
  219         u_int32_t rtalert = ~0;
  220         int nxt, ours = 0;
  221         struct ifnet *deliverifp = NULL;
  222         struct in6_addr odst;
  223         int srcrt = 0;
  224 
  225         GIANT_REQUIRED;                 /* XXX for now */
  226 
  227 #ifdef IPSEC
  228         /*
  229          * should the inner packet be considered authentic?
  230          * see comment in ah4_input().
  231          * NB: m cannot be NULL when passed to the input routine
  232          */
  233 
  234         m->m_flags &= ~M_AUTHIPHDR;
  235         m->m_flags &= ~M_AUTHIPDGM;
  236 
  237 #endif /* IPSEC */
  238 
  239         /*
  240          * make sure we don't have onion peering information into m_tag.
  241          */
  242         ip6_delaux(m);
  243 
  244         /*
  245          * mbuf statistics
  246          */
  247         if (m->m_flags & M_EXT) {
  248                 if (m->m_next)
  249                         ip6stat.ip6s_mext2m++;
  250                 else
  251                         ip6stat.ip6s_mext1++;
  252         } else {
  253 #define M2MMAX  (sizeof(ip6stat.ip6s_m2m)/sizeof(ip6stat.ip6s_m2m[0]))
  254                 if (m->m_next) {
  255                         if (m->m_flags & M_LOOP) {
  256                                 ip6stat.ip6s_m2m[loif[0].if_index]++; /* XXX */
  257                         } else if (m->m_pkthdr.rcvif->if_index < M2MMAX)
  258                                 ip6stat.ip6s_m2m[m->m_pkthdr.rcvif->if_index]++;
  259                         else
  260                                 ip6stat.ip6s_m2m[0]++;
  261                 } else
  262                         ip6stat.ip6s_m1++;
  263 #undef M2MMAX
  264         }
  265 
  266         /* drop the packet if IPv6 operation is disabled on the IF */
  267         if ((ND_IFINFO(m->m_pkthdr.rcvif)->flags & ND6_IFF_IFDISABLED)) {
  268                 m_freem(m);
  269                 return;
  270         }
  271 
  272         in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_receive);
  273         ip6stat.ip6s_total++;
  274 
  275 #ifndef PULLDOWN_TEST
  276         /*
  277          * L2 bridge code and some other code can return mbuf chain
  278          * that does not conform to KAME requirement.  too bad.
  279          * XXX: fails to join if interface MTU > MCLBYTES.  jumbogram?
  280          */
  281         if (m && m->m_next != NULL && m->m_pkthdr.len < MCLBYTES) {
  282                 struct mbuf *n;
  283 
  284                 MGETHDR(n, M_DONTWAIT, MT_HEADER);
  285                 if (n)
  286                         M_MOVE_PKTHDR(n, m);
  287                 if (n && n->m_pkthdr.len > MHLEN) {
  288                         MCLGET(n, M_DONTWAIT);
  289                         if ((n->m_flags & M_EXT) == 0) {
  290                                 m_freem(n);
  291                                 n = NULL;
  292                         }
  293                 }
  294                 if (n == NULL) {
  295                         m_freem(m);
  296                         return; /* ENOBUFS */
  297                 }
  298 
  299                 m_copydata(m, 0, n->m_pkthdr.len, mtod(n, caddr_t));
  300                 n->m_len = n->m_pkthdr.len;
  301                 m_freem(m);
  302                 m = n;
  303         }
  304         IP6_EXTHDR_CHECK(m, 0, sizeof(struct ip6_hdr), /* nothing */);
  305 #endif
  306 
  307         if (m->m_len < sizeof(struct ip6_hdr)) {
  308                 struct ifnet *inifp;
  309                 inifp = m->m_pkthdr.rcvif;
  310                 if ((m = m_pullup(m, sizeof(struct ip6_hdr))) == NULL) {
  311                         ip6stat.ip6s_toosmall++;
  312                         in6_ifstat_inc(inifp, ifs6_in_hdrerr);
  313                         return;
  314                 }
  315         }
  316 
  317         ip6 = mtod(m, struct ip6_hdr *);
  318 
  319         if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) {
  320                 ip6stat.ip6s_badvers++;
  321                 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_hdrerr);
  322                 goto bad;
  323         }
  324 
  325         ip6stat.ip6s_nxthist[ip6->ip6_nxt]++;
  326 
  327         /*
  328          * Check against address spoofing/corruption.
  329          */
  330         if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_src) ||
  331             IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_dst)) {
  332                 /*
  333                  * XXX: "badscope" is not very suitable for a multicast source.
  334                  */
  335                 ip6stat.ip6s_badscope++;
  336                 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
  337                 goto bad;
  338         }
  339         if (IN6_IS_ADDR_MC_INTFACELOCAL(&ip6->ip6_dst) &&
  340             !(m->m_flags & M_LOOP)) {
  341                 /*
  342                  * In this case, the packet should come from the loopback
  343                  * interface.  However, we cannot just check the if_flags,
  344                  * because ip6_mloopback() passes the "actual" interface
  345                  * as the outgoing/incoming interface.
  346                  */
  347                 ip6stat.ip6s_badscope++;
  348                 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
  349                 goto bad;
  350         }
  351 
  352 #ifdef ALTQ
  353         if (altq_input != NULL && (*altq_input)(m, AF_INET6) == 0) {
  354                 /* packet is dropped by traffic conditioner */
  355                 return;
  356         }
  357 #endif
  358         /*
  359          * The following check is not documented in specs.  A malicious
  360          * party may be able to use IPv4 mapped addr to confuse tcp/udp stack
  361          * and bypass security checks (act as if it was from 127.0.0.1 by using
  362          * IPv6 src ::ffff:127.0.0.1).  Be cautious.
  363          *
  364          * This check chokes if we are in an SIIT cloud.  As none of BSDs
  365          * support IPv4-less kernel compilation, we cannot support SIIT
  366          * environment at all.  So, it makes more sense for us to reject any
  367          * malicious packets for non-SIIT environment, than try to do a
  368          * partial support for SIIT environment.
  369          */
  370         if (IN6_IS_ADDR_V4MAPPED(&ip6->ip6_src) ||
  371             IN6_IS_ADDR_V4MAPPED(&ip6->ip6_dst)) {
  372                 ip6stat.ip6s_badscope++;
  373                 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
  374                 goto bad;
  375         }
  376 #if 0
  377         /*
  378          * Reject packets with IPv4 compatible addresses (auto tunnel).
  379          *
  380          * The code forbids auto tunnel relay case in RFC1933 (the check is
  381          * stronger than RFC1933).  We may want to re-enable it if mech-xx
  382          * is revised to forbid relaying case.
  383          */
  384         if (IN6_IS_ADDR_V4COMPAT(&ip6->ip6_src) ||
  385             IN6_IS_ADDR_V4COMPAT(&ip6->ip6_dst)) {
  386                 ip6stat.ip6s_badscope++;
  387                 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
  388                 goto bad;
  389         }
  390 #endif
  391 
  392         /*
  393          * Run through list of hooks for input packets.
  394          *
  395          * NB: Beware of the destination address changing
  396          *     (e.g. by NAT rewriting).  When this happens,
  397          *     tell ip6_forward to do the right thing.
  398          */
  399         odst = ip6->ip6_dst;
  400 
  401         /* Jump over all PFIL processing if hooks are not active. */
  402         if (!PFIL_HOOKED(&inet6_pfil_hook))
  403                 goto passin;
  404 
  405         if (pfil_run_hooks(&inet6_pfil_hook, &m, m->m_pkthdr.rcvif, PFIL_IN, NULL))
  406                 return;
  407         if (m == NULL)                  /* consumed by filter */
  408                 return;
  409         ip6 = mtod(m, struct ip6_hdr *);
  410         srcrt = !IN6_ARE_ADDR_EQUAL(&odst, &ip6->ip6_dst);
  411 
  412 passin:
  413         /*
  414          * Disambiguate address scope zones (if there is ambiguity).
  415          * We first make sure that the original source or destination address
  416          * is not in our internal form for scoped addresses.  Such addresses
  417          * are not necessarily invalid spec-wise, but we cannot accept them due
  418          * to the usage conflict.
  419          * in6_setscope() then also checks and rejects the cases where src or
  420          * dst are the loopback address and the receiving interface
  421          * is not loopback.
  422          */
  423         if (in6_clearscope(&ip6->ip6_src) || in6_clearscope(&ip6->ip6_dst)) {
  424                 ip6stat.ip6s_badscope++; /* XXX */
  425                 goto bad;
  426         }
  427         if (in6_setscope(&ip6->ip6_src, m->m_pkthdr.rcvif, NULL) ||
  428             in6_setscope(&ip6->ip6_dst, m->m_pkthdr.rcvif, NULL)) {
  429                 ip6stat.ip6s_badscope++;
  430                 goto bad;
  431         }
  432 
  433         /*
  434          * Multicast check
  435          */
  436         if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
  437                 struct in6_multi *in6m = 0;
  438 
  439                 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_mcast);
  440                 /*
  441                  * See if we belong to the destination multicast group on the
  442                  * arrival interface.
  443                  */
  444                 IN6_LOOKUP_MULTI(ip6->ip6_dst, m->m_pkthdr.rcvif, in6m);
  445                 if (in6m)
  446                         ours = 1;
  447                 else if (!ip6_mrouter) {
  448                         ip6stat.ip6s_notmember++;
  449                         ip6stat.ip6s_cantforward++;
  450                         in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
  451                         goto bad;
  452                 }
  453                 deliverifp = m->m_pkthdr.rcvif;
  454                 goto hbhcheck;
  455         }
  456 
  457         /*
  458          *  Unicast check
  459          */
  460         if (ip6_forward_rt.ro_rt != NULL &&
  461             (ip6_forward_rt.ro_rt->rt_flags & RTF_UP) != 0 &&
  462             IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst,
  463             &((struct sockaddr_in6 *)(&ip6_forward_rt.ro_dst))->sin6_addr))
  464                 ip6stat.ip6s_forward_cachehit++;
  465         else {
  466                 struct sockaddr_in6 *dst6;
  467 
  468                 if (ip6_forward_rt.ro_rt) {
  469                         /* route is down or destination is different */
  470                         ip6stat.ip6s_forward_cachemiss++;
  471                         RTFREE(ip6_forward_rt.ro_rt);
  472                         ip6_forward_rt.ro_rt = 0;
  473                 }
  474 
  475                 bzero(&ip6_forward_rt.ro_dst, sizeof(struct sockaddr_in6));
  476                 dst6 = (struct sockaddr_in6 *)&ip6_forward_rt.ro_dst;
  477                 dst6->sin6_len = sizeof(struct sockaddr_in6);
  478                 dst6->sin6_family = AF_INET6;
  479                 dst6->sin6_addr = ip6->ip6_dst;
  480 
  481                 rtalloc((struct route *)&ip6_forward_rt);
  482         }
  483 
  484 #define rt6_key(r) ((struct sockaddr_in6 *)((r)->rt_nodes->rn_key))
  485 
  486         /*
  487          * Accept the packet if the forwarding interface to the destination
  488          * according to the routing table is the loopback interface,
  489          * unless the associated route has a gateway.
  490          * Note that this approach causes to accept a packet if there is a
  491          * route to the loopback interface for the destination of the packet.
  492          * But we think it's even useful in some situations, e.g. when using
  493          * a special daemon which wants to intercept the packet.
  494          *
  495          * XXX: some OSes automatically make a cloned route for the destination
  496          * of an outgoing packet.  If the outgoing interface of the packet
  497          * is a loopback one, the kernel would consider the packet to be
  498          * accepted, even if we have no such address assinged on the interface.
  499          * We check the cloned flag of the route entry to reject such cases,
  500          * assuming that route entries for our own addresses are not made by
  501          * cloning (it should be true because in6_addloop explicitly installs
  502          * the host route).  However, we might have to do an explicit check
  503          * while it would be less efficient.  Or, should we rather install a
  504          * reject route for such a case?
  505          */
  506         if (ip6_forward_rt.ro_rt &&
  507             (ip6_forward_rt.ro_rt->rt_flags &
  508              (RTF_HOST|RTF_GATEWAY)) == RTF_HOST &&
  509 #ifdef RTF_WASCLONED
  510             !(ip6_forward_rt.ro_rt->rt_flags & RTF_WASCLONED) &&
  511 #endif
  512 #ifdef RTF_CLONED
  513             !(ip6_forward_rt.ro_rt->rt_flags & RTF_CLONED) &&
  514 #endif
  515 #if 0
  516             /*
  517              * The check below is redundant since the comparison of
  518              * the destination and the key of the rtentry has
  519              * already done through looking up the routing table.
  520              */
  521             IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst,
  522             &rt6_key(ip6_forward_rt.ro_rt)->sin6_addr)
  523 #endif
  524             ip6_forward_rt.ro_rt->rt_ifp->if_type == IFT_LOOP) {
  525                 struct in6_ifaddr *ia6 =
  526                         (struct in6_ifaddr *)ip6_forward_rt.ro_rt->rt_ifa;
  527 
  528                 /*
  529                  * record address information into m_tag.
  530                  */
  531                 (void)ip6_setdstifaddr(m, ia6);
  532 
  533                 /*
  534                  * packets to a tentative, duplicated, or somehow invalid
  535                  * address must not be accepted.
  536                  */
  537                 if (!(ia6->ia6_flags & IN6_IFF_NOTREADY)) {
  538                         /* this address is ready */
  539                         ours = 1;
  540                         deliverifp = ia6->ia_ifp;       /* correct? */
  541                         /* Count the packet in the ip address stats */
  542                         ia6->ia_ifa.if_ipackets++;
  543                         ia6->ia_ifa.if_ibytes += m->m_pkthdr.len;
  544                         goto hbhcheck;
  545                 } else {
  546                         char ip6bufs[INET6_ADDRSTRLEN];
  547                         char ip6bufd[INET6_ADDRSTRLEN];
  548                         /* address is not ready, so discard the packet. */
  549                         nd6log((LOG_INFO,
  550                             "ip6_input: packet to an unready address %s->%s\n",
  551                             ip6_sprintf(ip6bufs, &ip6->ip6_src),
  552                             ip6_sprintf(ip6bufd, &ip6->ip6_dst)));
  553 
  554                         goto bad;
  555                 }
  556         }
  557 
  558         /*
  559          * FAITH (Firewall Aided Internet Translator)
  560          */
  561         if (ip6_keepfaith) {
  562                 if (ip6_forward_rt.ro_rt && ip6_forward_rt.ro_rt->rt_ifp
  563                  && ip6_forward_rt.ro_rt->rt_ifp->if_type == IFT_FAITH) {
  564                         /* XXX do we need more sanity checks? */
  565                         ours = 1;
  566                         deliverifp = ip6_forward_rt.ro_rt->rt_ifp; /* faith */
  567                         goto hbhcheck;
  568                 }
  569         }
  570 
  571         /*
  572          * Now there is no reason to process the packet if it's not our own
  573          * and we're not a router.
  574          */
  575         if (!ip6_forwarding) {
  576                 ip6stat.ip6s_cantforward++;
  577                 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
  578                 goto bad;
  579         }
  580 
  581   hbhcheck:
  582         /*
  583          * record address information into m_tag, if we don't have one yet.
  584          * note that we are unable to record it, if the address is not listed
  585          * as our interface address (e.g. multicast addresses, addresses
  586          * within FAITH prefixes and such).
  587          */
  588         if (deliverifp && !ip6_getdstifaddr(m)) {
  589                 struct in6_ifaddr *ia6;
  590 
  591                 ia6 = in6_ifawithifp(deliverifp, &ip6->ip6_dst);
  592                 if (ia6) {
  593                         if (!ip6_setdstifaddr(m, ia6)) {
  594                                 /*
  595                                  * XXX maybe we should drop the packet here,
  596                                  * as we could not provide enough information
  597                                  * to the upper layers.
  598                                  */
  599                         }
  600                 }
  601         }
  602 
  603         /*
  604          * Process Hop-by-Hop options header if it's contained.
  605          * m may be modified in ip6_hopopts_input().
  606          * If a JumboPayload option is included, plen will also be modified.
  607          */
  608         plen = (u_int32_t)ntohs(ip6->ip6_plen);
  609         if (ip6->ip6_nxt == IPPROTO_HOPOPTS) {
  610                 struct ip6_hbh *hbh;
  611 
  612                 if (ip6_hopopts_input(&plen, &rtalert, &m, &off)) {
  613 #if 0   /*touches NULL pointer*/
  614                         in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
  615 #endif
  616                         return; /* m have already been freed */
  617                 }
  618 
  619                 /* adjust pointer */
  620                 ip6 = mtod(m, struct ip6_hdr *);
  621 
  622                 /*
  623                  * if the payload length field is 0 and the next header field
  624                  * indicates Hop-by-Hop Options header, then a Jumbo Payload
  625                  * option MUST be included.
  626                  */
  627                 if (ip6->ip6_plen == 0 && plen == 0) {
  628                         /*
  629                          * Note that if a valid jumbo payload option is
  630                          * contained, ip6_hopopts_input() must set a valid
  631                          * (non-zero) payload length to the variable plen.
  632                          */
  633                         ip6stat.ip6s_badoptions++;
  634                         in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
  635                         in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_hdrerr);
  636                         icmp6_error(m, ICMP6_PARAM_PROB,
  637                                     ICMP6_PARAMPROB_HEADER,
  638                                     (caddr_t)&ip6->ip6_plen - (caddr_t)ip6);
  639                         return;
  640                 }
  641 #ifndef PULLDOWN_TEST
  642                 /* ip6_hopopts_input() ensures that mbuf is contiguous */
  643                 hbh = (struct ip6_hbh *)(ip6 + 1);
  644 #else
  645                 IP6_EXTHDR_GET(hbh, struct ip6_hbh *, m, sizeof(struct ip6_hdr),
  646                         sizeof(struct ip6_hbh));
  647                 if (hbh == NULL) {
  648                         ip6stat.ip6s_tooshort++;
  649                         return;
  650                 }
  651 #endif
  652                 nxt = hbh->ip6h_nxt;
  653 
  654                 /*
  655                  * If we are acting as a router and the packet contains a
  656                  * router alert option, see if we know the option value.
  657                  * Currently, we only support the option value for MLD, in which
  658                  * case we should pass the packet to the multicast routing
  659                  * daemon.
  660                  */
  661                 if (rtalert != ~0 && ip6_forwarding) {
  662                         switch (rtalert) {
  663                         case IP6OPT_RTALERT_MLD:
  664                                 ours = 1;
  665                                 break;
  666                         default:
  667                                 /*
  668                                  * RFC2711 requires unrecognized values must be
  669                                  * silently ignored.
  670                                  */
  671                                 break;
  672                         }
  673                 }
  674         } else
  675                 nxt = ip6->ip6_nxt;
  676 
  677         /*
  678          * Check that the amount of data in the buffers
  679          * is as at least much as the IPv6 header would have us expect.
  680          * Trim mbufs if longer than we expect.
  681          * Drop packet if shorter than we expect.
  682          */
  683         if (m->m_pkthdr.len - sizeof(struct ip6_hdr) < plen) {
  684                 ip6stat.ip6s_tooshort++;
  685                 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_truncated);
  686                 goto bad;
  687         }
  688         if (m->m_pkthdr.len > sizeof(struct ip6_hdr) + plen) {
  689                 if (m->m_len == m->m_pkthdr.len) {
  690                         m->m_len = sizeof(struct ip6_hdr) + plen;
  691                         m->m_pkthdr.len = sizeof(struct ip6_hdr) + plen;
  692                 } else
  693                         m_adj(m, sizeof(struct ip6_hdr) + plen - m->m_pkthdr.len);
  694         }
  695 
  696         /*
  697          * Forward if desirable.
  698          */
  699         if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
  700                 /*
  701                  * If we are acting as a multicast router, all
  702                  * incoming multicast packets are passed to the
  703                  * kernel-level multicast forwarding function.
  704                  * The packet is returned (relatively) intact; if
  705                  * ip6_mforward() returns a non-zero value, the packet
  706                  * must be discarded, else it may be accepted below.
  707                  */
  708                 if (ip6_mrouter && ip6_mforward &&
  709                     ip6_mforward(ip6, m->m_pkthdr.rcvif, m)) {
  710                         ip6stat.ip6s_cantforward++;
  711                         m_freem(m);
  712                         return;
  713                 }
  714                 if (!ours) {
  715                         m_freem(m);
  716                         return;
  717                 }
  718         } else if (!ours) {
  719                 ip6_forward(m, srcrt);
  720                 return;
  721         }
  722 
  723         ip6 = mtod(m, struct ip6_hdr *);
  724 
  725         /*
  726          * Malicious party may be able to use IPv4 mapped addr to confuse
  727          * tcp/udp stack and bypass security checks (act as if it was from
  728          * 127.0.0.1 by using IPv6 src ::ffff:127.0.0.1).  Be cautious.
  729          *
  730          * For SIIT end node behavior, you may want to disable the check.
  731          * However, you will  become vulnerable to attacks using IPv4 mapped
  732          * source.
  733          */
  734         if (IN6_IS_ADDR_V4MAPPED(&ip6->ip6_src) ||
  735             IN6_IS_ADDR_V4MAPPED(&ip6->ip6_dst)) {
  736                 ip6stat.ip6s_badscope++;
  737                 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
  738                 goto bad;
  739         }
  740 
  741         /*
  742          * Tell launch routine the next header
  743          */
  744         ip6stat.ip6s_delivered++;
  745         in6_ifstat_inc(deliverifp, ifs6_in_deliver);
  746         nest = 0;
  747 
  748         while (nxt != IPPROTO_DONE) {
  749                 if (ip6_hdrnestlimit && (++nest > ip6_hdrnestlimit)) {
  750                         ip6stat.ip6s_toomanyhdr++;
  751                         goto bad;
  752                 }
  753 
  754                 /*
  755                  * protection against faulty packet - there should be
  756                  * more sanity checks in header chain processing.
  757                  */
  758                 if (m->m_pkthdr.len < off) {
  759                         ip6stat.ip6s_tooshort++;
  760                         in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_truncated);
  761                         goto bad;
  762                 }
  763 
  764 #ifdef IPSEC
  765                 /*
  766                  * enforce IPsec policy checking if we are seeing last header.
  767                  * note that we do not visit this with protocols with pcb layer
  768                  * code - like udp/tcp/raw ip.
  769                  */
  770                 if (ip6_ipsec_input(m, nxt))
  771                         goto bad;
  772 #endif /* IPSEC */
  773                 nxt = (*inet6sw[ip6_protox[nxt]].pr_input)(&m, &off, nxt);
  774         }
  775         return;
  776  bad:
  777         m_freem(m);
  778 }
  779 
  780 /*
  781  * set/grab in6_ifaddr correspond to IPv6 destination address.
  782  * XXX backward compatibility wrapper
  783  */
  784 static struct ip6aux *
  785 ip6_setdstifaddr(struct mbuf *m, struct in6_ifaddr *ia6)
  786 {
  787         struct ip6aux *ip6a;
  788 
  789         ip6a = ip6_addaux(m);
  790         if (ip6a)
  791                 ip6a->ip6a_dstia6 = ia6;
  792         return ip6a;    /* NULL if failed to set */
  793 }
  794 
  795 struct in6_ifaddr *
  796 ip6_getdstifaddr(struct mbuf *m)
  797 {
  798         struct ip6aux *ip6a;
  799 
  800         ip6a = ip6_findaux(m);
  801         if (ip6a)
  802                 return ip6a->ip6a_dstia6;
  803         else
  804                 return NULL;
  805 }
  806 
  807 /*
  808  * Hop-by-Hop options header processing. If a valid jumbo payload option is
  809  * included, the real payload length will be stored in plenp.
  810  *
  811  * rtalertp - XXX: should be stored more smart way
  812  */
  813 static int
  814 ip6_hopopts_input(u_int32_t *plenp, u_int32_t *rtalertp,
  815     struct mbuf **mp, int *offp)
  816 {
  817         struct mbuf *m = *mp;
  818         int off = *offp, hbhlen;
  819         struct ip6_hbh *hbh;
  820         u_int8_t *opt;
  821 
  822         /* validation of the length of the header */
  823 #ifndef PULLDOWN_TEST
  824         IP6_EXTHDR_CHECK(m, off, sizeof(*hbh), -1);
  825         hbh = (struct ip6_hbh *)(mtod(m, caddr_t) + off);
  826         hbhlen = (hbh->ip6h_len + 1) << 3;
  827 
  828         IP6_EXTHDR_CHECK(m, off, hbhlen, -1);
  829         hbh = (struct ip6_hbh *)(mtod(m, caddr_t) + off);
  830 #else
  831         IP6_EXTHDR_GET(hbh, struct ip6_hbh *, m,
  832                 sizeof(struct ip6_hdr), sizeof(struct ip6_hbh));
  833         if (hbh == NULL) {
  834                 ip6stat.ip6s_tooshort++;
  835                 return -1;
  836         }
  837         hbhlen = (hbh->ip6h_len + 1) << 3;
  838         IP6_EXTHDR_GET(hbh, struct ip6_hbh *, m, sizeof(struct ip6_hdr),
  839                 hbhlen);
  840         if (hbh == NULL) {
  841                 ip6stat.ip6s_tooshort++;
  842                 return -1;
  843         }
  844 #endif
  845         off += hbhlen;
  846         hbhlen -= sizeof(struct ip6_hbh);
  847         opt = (u_int8_t *)hbh + sizeof(struct ip6_hbh);
  848 
  849         if (ip6_process_hopopts(m, (u_int8_t *)hbh + sizeof(struct ip6_hbh),
  850                                 hbhlen, rtalertp, plenp) < 0)
  851                 return (-1);
  852 
  853         *offp = off;
  854         *mp = m;
  855         return (0);
  856 }
  857 
  858 /*
  859  * Search header for all Hop-by-hop options and process each option.
  860  * This function is separate from ip6_hopopts_input() in order to
  861  * handle a case where the sending node itself process its hop-by-hop
  862  * options header. In such a case, the function is called from ip6_output().
  863  *
  864  * The function assumes that hbh header is located right after the IPv6 header
  865  * (RFC2460 p7), opthead is pointer into data content in m, and opthead to
  866  * opthead + hbhlen is located in continuous memory region.
  867  */
  868 int
  869 ip6_process_hopopts(struct mbuf *m, u_int8_t *opthead, int hbhlen,
  870     u_int32_t *rtalertp, u_int32_t *plenp)
  871 {
  872         struct ip6_hdr *ip6;
  873         int optlen = 0;
  874         u_int8_t *opt = opthead;
  875         u_int16_t rtalert_val;
  876         u_int32_t jumboplen;
  877         const int erroff = sizeof(struct ip6_hdr) + sizeof(struct ip6_hbh);
  878 
  879         for (; hbhlen > 0; hbhlen -= optlen, opt += optlen) {
  880                 switch (*opt) {
  881                 case IP6OPT_PAD1:
  882                         optlen = 1;
  883                         break;
  884                 case IP6OPT_PADN:
  885                         if (hbhlen < IP6OPT_MINLEN) {
  886                                 ip6stat.ip6s_toosmall++;
  887                                 goto bad;
  888                         }
  889                         optlen = *(opt + 1) + 2;
  890                         break;
  891                 case IP6OPT_ROUTER_ALERT:
  892                         /* XXX may need check for alignment */
  893                         if (hbhlen < IP6OPT_RTALERT_LEN) {
  894                                 ip6stat.ip6s_toosmall++;
  895                                 goto bad;
  896                         }
  897                         if (*(opt + 1) != IP6OPT_RTALERT_LEN - 2) {
  898                                 /* XXX stat */
  899                                 icmp6_error(m, ICMP6_PARAM_PROB,
  900                                     ICMP6_PARAMPROB_HEADER,
  901                                     erroff + opt + 1 - opthead);
  902                                 return (-1);
  903                         }
  904                         optlen = IP6OPT_RTALERT_LEN;
  905                         bcopy((caddr_t)(opt + 2), (caddr_t)&rtalert_val, 2);
  906                         *rtalertp = ntohs(rtalert_val);
  907                         break;
  908                 case IP6OPT_JUMBO:
  909                         /* XXX may need check for alignment */
  910                         if (hbhlen < IP6OPT_JUMBO_LEN) {
  911                                 ip6stat.ip6s_toosmall++;
  912                                 goto bad;
  913                         }
  914                         if (*(opt + 1) != IP6OPT_JUMBO_LEN - 2) {
  915                                 /* XXX stat */
  916                                 icmp6_error(m, ICMP6_PARAM_PROB,
  917                                     ICMP6_PARAMPROB_HEADER,
  918                                     erroff + opt + 1 - opthead);
  919                                 return (-1);
  920                         }
  921                         optlen = IP6OPT_JUMBO_LEN;
  922 
  923                         /*
  924                          * IPv6 packets that have non 0 payload length
  925                          * must not contain a jumbo payload option.
  926                          */
  927                         ip6 = mtod(m, struct ip6_hdr *);
  928                         if (ip6->ip6_plen) {
  929                                 ip6stat.ip6s_badoptions++;
  930                                 icmp6_error(m, ICMP6_PARAM_PROB,
  931                                     ICMP6_PARAMPROB_HEADER,
  932                                     erroff + opt - opthead);
  933                                 return (-1);
  934                         }
  935 
  936                         /*
  937                          * We may see jumbolen in unaligned location, so
  938                          * we'd need to perform bcopy().
  939                          */
  940                         bcopy(opt + 2, &jumboplen, sizeof(jumboplen));
  941                         jumboplen = (u_int32_t)htonl(jumboplen);
  942 
  943 #if 1
  944                         /*
  945                          * if there are multiple jumbo payload options,
  946                          * *plenp will be non-zero and the packet will be
  947                          * rejected.
  948                          * the behavior may need some debate in ipngwg -
  949                          * multiple options does not make sense, however,
  950                          * there's no explicit mention in specification.
  951                          */
  952                         if (*plenp != 0) {
  953                                 ip6stat.ip6s_badoptions++;
  954                                 icmp6_error(m, ICMP6_PARAM_PROB,
  955                                     ICMP6_PARAMPROB_HEADER,
  956                                     erroff + opt + 2 - opthead);
  957                                 return (-1);
  958                         }
  959 #endif
  960 
  961                         /*
  962                          * jumbo payload length must be larger than 65535.
  963                          */
  964                         if (jumboplen <= IPV6_MAXPACKET) {
  965                                 ip6stat.ip6s_badoptions++;
  966                                 icmp6_error(m, ICMP6_PARAM_PROB,
  967                                     ICMP6_PARAMPROB_HEADER,
  968                                     erroff + opt + 2 - opthead);
  969                                 return (-1);
  970                         }
  971                         *plenp = jumboplen;
  972 
  973                         break;
  974                 default:                /* unknown option */
  975                         if (hbhlen < IP6OPT_MINLEN) {
  976                                 ip6stat.ip6s_toosmall++;
  977                                 goto bad;
  978                         }
  979                         optlen = ip6_unknown_opt(opt, m,
  980                             erroff + opt - opthead);
  981                         if (optlen == -1)
  982                                 return (-1);
  983                         optlen += 2;
  984                         break;
  985                 }
  986         }
  987 
  988         return (0);
  989 
  990   bad:
  991         m_freem(m);
  992         return (-1);
  993 }
  994 
  995 /*
  996  * Unknown option processing.
  997  * The third argument `off' is the offset from the IPv6 header to the option,
  998  * which is necessary if the IPv6 header the and option header and IPv6 header
  999  * is not continuous in order to return an ICMPv6 error.
 1000  */
 1001 int
 1002 ip6_unknown_opt(u_int8_t *optp, struct mbuf *m, int off)
 1003 {
 1004         struct ip6_hdr *ip6;
 1005 
 1006         switch (IP6OPT_TYPE(*optp)) {
 1007         case IP6OPT_TYPE_SKIP: /* ignore the option */
 1008                 return ((int)*(optp + 1));
 1009         case IP6OPT_TYPE_DISCARD:       /* silently discard */
 1010                 m_freem(m);
 1011                 return (-1);
 1012         case IP6OPT_TYPE_FORCEICMP: /* send ICMP even if multicasted */
 1013                 ip6stat.ip6s_badoptions++;
 1014                 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_OPTION, off);
 1015                 return (-1);
 1016         case IP6OPT_TYPE_ICMP: /* send ICMP if not multicasted */
 1017                 ip6stat.ip6s_badoptions++;
 1018                 ip6 = mtod(m, struct ip6_hdr *);
 1019                 if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) ||
 1020                     (m->m_flags & (M_BCAST|M_MCAST)))
 1021                         m_freem(m);
 1022                 else
 1023                         icmp6_error(m, ICMP6_PARAM_PROB,
 1024                                     ICMP6_PARAMPROB_OPTION, off);
 1025                 return (-1);
 1026         }
 1027 
 1028         m_freem(m);             /* XXX: NOTREACHED */
 1029         return (-1);
 1030 }
 1031 
 1032 /*
 1033  * Create the "control" list for this pcb.
 1034  * These functions will not modify mbuf chain at all.
 1035  *
 1036  * With KAME mbuf chain restriction:
 1037  * The routine will be called from upper layer handlers like tcp6_input().
 1038  * Thus the routine assumes that the caller (tcp6_input) have already
 1039  * called IP6_EXTHDR_CHECK() and all the extension headers are located in the
 1040  * very first mbuf on the mbuf chain.
 1041  *
 1042  * ip6_savecontrol_v4 will handle those options that are possible to be
 1043  * set on a v4-mapped socket.
 1044  * ip6_savecontrol will directly call ip6_savecontrol_v4 to handle those
 1045  * options and handle the v6-only ones itself.
 1046  */
 1047 struct mbuf **
 1048 ip6_savecontrol_v4(struct inpcb *inp, struct mbuf *m, struct mbuf **mp,
 1049     int *v4only)
 1050 {
 1051         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
 1052 
 1053 #ifdef SO_TIMESTAMP
 1054         if ((inp->inp_socket->so_options & SO_TIMESTAMP) != 0) {
 1055                 struct timeval tv;
 1056 
 1057                 microtime(&tv);
 1058                 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv),
 1059                     SCM_TIMESTAMP, SOL_SOCKET);
 1060                 if (*mp)
 1061                         mp = &(*mp)->m_next;
 1062         }
 1063 #endif
 1064 
 1065         if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) {
 1066                 if (v4only != NULL)
 1067                         *v4only = 1;
 1068                 return (mp);
 1069         }
 1070 
 1071 #define IS2292(inp, x, y)       (((inp)->inp_flags & IN6P_RFC2292) ? (x) : (y))
 1072         /* RFC 2292 sec. 5 */
 1073         if ((inp->inp_flags & IN6P_PKTINFO) != 0) {
 1074                 struct in6_pktinfo pi6;
 1075 
 1076                 bcopy(&ip6->ip6_dst, &pi6.ipi6_addr, sizeof(struct in6_addr));
 1077                 in6_clearscope(&pi6.ipi6_addr); /* XXX */
 1078                 pi6.ipi6_ifindex =
 1079                     (m && m->m_pkthdr.rcvif) ? m->m_pkthdr.rcvif->if_index : 0;
 1080 
 1081                 *mp = sbcreatecontrol((caddr_t) &pi6,
 1082                     sizeof(struct in6_pktinfo),
 1083                     IS2292(inp, IPV6_2292PKTINFO, IPV6_PKTINFO), IPPROTO_IPV6);
 1084                 if (*mp)
 1085                         mp = &(*mp)->m_next;
 1086         }
 1087 
 1088         if ((inp->inp_flags & IN6P_HOPLIMIT) != 0) {
 1089                 int hlim = ip6->ip6_hlim & 0xff;
 1090 
 1091                 *mp = sbcreatecontrol((caddr_t) &hlim, sizeof(int),
 1092                     IS2292(inp, IPV6_2292HOPLIMIT, IPV6_HOPLIMIT),
 1093                     IPPROTO_IPV6);
 1094                 if (*mp)
 1095                         mp = &(*mp)->m_next;
 1096         }
 1097 
 1098         if (v4only != NULL)
 1099                 *v4only = 0;
 1100         return (mp);
 1101 }
 1102 
 1103 void
 1104 ip6_savecontrol(struct inpcb *in6p, struct mbuf *m, struct mbuf **mp)
 1105 {
 1106         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
 1107         int v4only = 0;
 1108 
 1109         mp = ip6_savecontrol_v4(in6p, m, mp, &v4only);
 1110         if (v4only)
 1111                 return;
 1112 
 1113         if ((in6p->inp_flags & IN6P_TCLASS) != 0) {
 1114                 u_int32_t flowinfo;
 1115                 int tclass;
 1116 
 1117                 flowinfo = (u_int32_t)ntohl(ip6->ip6_flow & IPV6_FLOWINFO_MASK);
 1118                 flowinfo >>= 20;
 1119 
 1120                 tclass = flowinfo & 0xff;
 1121                 *mp = sbcreatecontrol((caddr_t) &tclass, sizeof(tclass),
 1122                     IPV6_TCLASS, IPPROTO_IPV6);
 1123                 if (*mp)
 1124                         mp = &(*mp)->m_next;
 1125         }
 1126 
 1127         /*
 1128          * IPV6_HOPOPTS socket option.  Recall that we required super-user
 1129          * privilege for the option (see ip6_ctloutput), but it might be too
 1130          * strict, since there might be some hop-by-hop options which can be
 1131          * returned to normal user.
 1132          * See also RFC 2292 section 6 (or RFC 3542 section 8).
 1133          */
 1134         if ((in6p->inp_flags & IN6P_HOPOPTS) != 0) {
 1135                 /*
 1136                  * Check if a hop-by-hop options header is contatined in the
 1137                  * received packet, and if so, store the options as ancillary
 1138                  * data. Note that a hop-by-hop options header must be
 1139                  * just after the IPv6 header, which is assured through the
 1140                  * IPv6 input processing.
 1141                  */
 1142                 if (ip6->ip6_nxt == IPPROTO_HOPOPTS) {
 1143                         struct ip6_hbh *hbh;
 1144                         int hbhlen = 0;
 1145 #ifdef PULLDOWN_TEST
 1146                         struct mbuf *ext;
 1147 #endif
 1148 
 1149 #ifndef PULLDOWN_TEST
 1150                         hbh = (struct ip6_hbh *)(ip6 + 1);
 1151                         hbhlen = (hbh->ip6h_len + 1) << 3;
 1152 #else
 1153                         ext = ip6_pullexthdr(m, sizeof(struct ip6_hdr),
 1154                             ip6->ip6_nxt);
 1155                         if (ext == NULL) {
 1156                                 ip6stat.ip6s_tooshort++;
 1157                                 return;
 1158                         }
 1159                         hbh = mtod(ext, struct ip6_hbh *);
 1160                         hbhlen = (hbh->ip6h_len + 1) << 3;
 1161                         if (hbhlen != ext->m_len) {
 1162                                 m_freem(ext);
 1163                                 ip6stat.ip6s_tooshort++;
 1164                                 return;
 1165                         }
 1166 #endif
 1167 
 1168                         /*
 1169                          * XXX: We copy the whole header even if a
 1170                          * jumbo payload option is included, the option which
 1171                          * is to be removed before returning according to
 1172                          * RFC2292.
 1173                          * Note: this constraint is removed in RFC3542
 1174                          */
 1175                         *mp = sbcreatecontrol((caddr_t)hbh, hbhlen,
 1176                             IS2292(in6p, IPV6_2292HOPOPTS, IPV6_HOPOPTS),
 1177                             IPPROTO_IPV6);
 1178                         if (*mp)
 1179                                 mp = &(*mp)->m_next;
 1180 #ifdef PULLDOWN_TEST
 1181                         m_freem(ext);
 1182 #endif
 1183                 }
 1184         }
 1185 
 1186         if ((in6p->inp_flags & (IN6P_RTHDR | IN6P_DSTOPTS)) != 0) {
 1187                 int nxt = ip6->ip6_nxt, off = sizeof(struct ip6_hdr);
 1188 
 1189                 /*
 1190                  * Search for destination options headers or routing
 1191                  * header(s) through the header chain, and stores each
 1192                  * header as ancillary data.
 1193                  * Note that the order of the headers remains in
 1194                  * the chain of ancillary data.
 1195                  */
 1196                 while (1) {     /* is explicit loop prevention necessary? */
 1197                         struct ip6_ext *ip6e = NULL;
 1198                         int elen;
 1199 #ifdef PULLDOWN_TEST
 1200                         struct mbuf *ext = NULL;
 1201 #endif
 1202 
 1203                         /*
 1204                          * if it is not an extension header, don't try to
 1205                          * pull it from the chain.
 1206                          */
 1207                         switch (nxt) {
 1208                         case IPPROTO_DSTOPTS:
 1209                         case IPPROTO_ROUTING:
 1210                         case IPPROTO_HOPOPTS:
 1211                         case IPPROTO_AH: /* is it possible? */
 1212                                 break;
 1213                         default:
 1214                                 goto loopend;
 1215                         }
 1216 
 1217 #ifndef PULLDOWN_TEST
 1218                         if (off + sizeof(*ip6e) > m->m_len)
 1219                                 goto loopend;
 1220                         ip6e = (struct ip6_ext *)(mtod(m, caddr_t) + off);
 1221                         if (nxt == IPPROTO_AH)
 1222                                 elen = (ip6e->ip6e_len + 2) << 2;
 1223                         else
 1224                                 elen = (ip6e->ip6e_len + 1) << 3;
 1225                         if (off + elen > m->m_len)
 1226                                 goto loopend;
 1227 #else
 1228                         ext = ip6_pullexthdr(m, off, nxt);
 1229                         if (ext == NULL) {
 1230                                 ip6stat.ip6s_tooshort++;
 1231                                 return;
 1232                         }
 1233                         ip6e = mtod(ext, struct ip6_ext *);
 1234                         if (nxt == IPPROTO_AH)
 1235                                 elen = (ip6e->ip6e_len + 2) << 2;
 1236                         else
 1237                                 elen = (ip6e->ip6e_len + 1) << 3;
 1238                         if (elen != ext->m_len) {
 1239                                 m_freem(ext);
 1240                                 ip6stat.ip6s_tooshort++;
 1241                                 return;
 1242                         }
 1243 #endif
 1244 
 1245                         switch (nxt) {
 1246                         case IPPROTO_DSTOPTS:
 1247                                 if (!(in6p->inp_flags & IN6P_DSTOPTS))
 1248                                         break;
 1249 
 1250                                 *mp = sbcreatecontrol((caddr_t)ip6e, elen,
 1251                                     IS2292(in6p,
 1252                                         IPV6_2292DSTOPTS, IPV6_DSTOPTS),
 1253                                     IPPROTO_IPV6);
 1254                                 if (*mp)
 1255                                         mp = &(*mp)->m_next;
 1256                                 break;
 1257                         case IPPROTO_ROUTING:
 1258                                 if (!in6p->inp_flags & IN6P_RTHDR)
 1259                                         break;
 1260 
 1261                                 *mp = sbcreatecontrol((caddr_t)ip6e, elen,
 1262                                     IS2292(in6p, IPV6_2292RTHDR, IPV6_RTHDR),
 1263                                     IPPROTO_IPV6);
 1264                                 if (*mp)
 1265                                         mp = &(*mp)->m_next;
 1266                                 break;
 1267                         case IPPROTO_HOPOPTS:
 1268                         case IPPROTO_AH: /* is it possible? */
 1269                                 break;
 1270 
 1271                         default:
 1272                                 /*
 1273                                  * other cases have been filtered in the above.
 1274                                  * none will visit this case.  here we supply
 1275                                  * the code just in case (nxt overwritten or
 1276                                  * other cases).
 1277                                  */
 1278 #ifdef PULLDOWN_TEST
 1279                                 m_freem(ext);
 1280 #endif
 1281                                 goto loopend;
 1282 
 1283                         }
 1284 
 1285                         /* proceed with the next header. */
 1286                         off += elen;
 1287                         nxt = ip6e->ip6e_nxt;
 1288                         ip6e = NULL;
 1289 #ifdef PULLDOWN_TEST
 1290                         m_freem(ext);
 1291                         ext = NULL;
 1292 #endif
 1293                 }
 1294           loopend:
 1295                 ;
 1296         }
 1297 }
 1298 #undef IS2292
 1299 
 1300 void
 1301 ip6_notify_pmtu(struct inpcb *in6p, struct sockaddr_in6 *dst, u_int32_t *mtu)
 1302 {
 1303         struct socket *so;
 1304         struct mbuf *m_mtu;
 1305         struct ip6_mtuinfo mtuctl;
 1306 
 1307         so =  in6p->inp_socket;
 1308 
 1309         if (mtu == NULL)
 1310                 return;
 1311 
 1312 #ifdef DIAGNOSTIC
 1313         if (so == NULL)         /* I believe this is impossible */
 1314                 panic("ip6_notify_pmtu: socket is NULL");
 1315 #endif
 1316 
 1317         bzero(&mtuctl, sizeof(mtuctl)); /* zero-clear for safety */
 1318         mtuctl.ip6m_mtu = *mtu;
 1319         mtuctl.ip6m_addr = *dst;
 1320         if (sa6_recoverscope(&mtuctl.ip6m_addr))
 1321                 return;
 1322 
 1323         if ((m_mtu = sbcreatecontrol((caddr_t)&mtuctl, sizeof(mtuctl),
 1324             IPV6_PATHMTU, IPPROTO_IPV6)) == NULL)
 1325                 return;
 1326 
 1327         if (sbappendaddr(&so->so_rcv, (struct sockaddr *)dst, NULL, m_mtu)
 1328             == 0) {
 1329                 m_freem(m_mtu);
 1330                 /* XXX: should count statistics */
 1331         } else
 1332                 sorwakeup(so);
 1333 
 1334         return;
 1335 }
 1336 
 1337 #ifdef PULLDOWN_TEST
 1338 /*
 1339  * pull single extension header from mbuf chain.  returns single mbuf that
 1340  * contains the result, or NULL on error.
 1341  */
 1342 static struct mbuf *
 1343 ip6_pullexthdr(struct mbuf *m, size_t off, int nxt)
 1344 {
 1345         struct ip6_ext ip6e;
 1346         size_t elen;
 1347         struct mbuf *n;
 1348 
 1349 #ifdef DIAGNOSTIC
 1350         switch (nxt) {
 1351         case IPPROTO_DSTOPTS:
 1352         case IPPROTO_ROUTING:
 1353         case IPPROTO_HOPOPTS:
 1354         case IPPROTO_AH: /* is it possible? */
 1355                 break;
 1356         default:
 1357                 printf("ip6_pullexthdr: invalid nxt=%d\n", nxt);
 1358         }
 1359 #endif
 1360 
 1361         m_copydata(m, off, sizeof(ip6e), (caddr_t)&ip6e);
 1362         if (nxt == IPPROTO_AH)
 1363                 elen = (ip6e.ip6e_len + 2) << 2;
 1364         else
 1365                 elen = (ip6e.ip6e_len + 1) << 3;
 1366 
 1367         MGET(n, M_DONTWAIT, MT_DATA);
 1368         if (n && elen >= MLEN) {
 1369                 MCLGET(n, M_DONTWAIT);
 1370                 if ((n->m_flags & M_EXT) == 0) {
 1371                         m_free(n);
 1372                         n = NULL;
 1373                 }
 1374         }
 1375         if (!n)
 1376                 return NULL;
 1377 
 1378         n->m_len = 0;
 1379         if (elen >= M_TRAILINGSPACE(n)) {
 1380                 m_free(n);
 1381                 return NULL;
 1382         }
 1383 
 1384         m_copydata(m, off, elen, mtod(n, caddr_t));
 1385         n->m_len = elen;
 1386         return n;
 1387 }
 1388 #endif
 1389 
 1390 /*
 1391  * Get pointer to the previous header followed by the header
 1392  * currently processed.
 1393  * XXX: This function supposes that
 1394  *      M includes all headers,
 1395  *      the next header field and the header length field of each header
 1396  *      are valid, and
 1397  *      the sum of each header length equals to OFF.
 1398  * Because of these assumptions, this function must be called very
 1399  * carefully. Moreover, it will not be used in the near future when
 1400  * we develop `neater' mechanism to process extension headers.
 1401  */
 1402 char *
 1403 ip6_get_prevhdr(struct mbuf *m, int off)
 1404 {
 1405         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
 1406 
 1407         if (off == sizeof(struct ip6_hdr))
 1408                 return (&ip6->ip6_nxt);
 1409         else {
 1410                 int len, nxt;
 1411                 struct ip6_ext *ip6e = NULL;
 1412 
 1413                 nxt = ip6->ip6_nxt;
 1414                 len = sizeof(struct ip6_hdr);
 1415                 while (len < off) {
 1416                         ip6e = (struct ip6_ext *)(mtod(m, caddr_t) + len);
 1417 
 1418                         switch (nxt) {
 1419                         case IPPROTO_FRAGMENT:
 1420                                 len += sizeof(struct ip6_frag);
 1421                                 break;
 1422                         case IPPROTO_AH:
 1423                                 len += (ip6e->ip6e_len + 2) << 2;
 1424                                 break;
 1425                         default:
 1426                                 len += (ip6e->ip6e_len + 1) << 3;
 1427                                 break;
 1428                         }
 1429                         nxt = ip6e->ip6e_nxt;
 1430                 }
 1431                 if (ip6e)
 1432                         return (&ip6e->ip6e_nxt);
 1433                 else
 1434                         return NULL;
 1435         }
 1436 }
 1437 
 1438 /*
 1439  * get next header offset.  m will be retained.
 1440  */
 1441 int
 1442 ip6_nexthdr(struct mbuf *m, int off, int proto, int *nxtp)
 1443 {
 1444         struct ip6_hdr ip6;
 1445         struct ip6_ext ip6e;
 1446         struct ip6_frag fh;
 1447 
 1448         /* just in case */
 1449         if (m == NULL)
 1450                 panic("ip6_nexthdr: m == NULL");
 1451         if ((m->m_flags & M_PKTHDR) == 0 || m->m_pkthdr.len < off)
 1452                 return -1;
 1453 
 1454         switch (proto) {
 1455         case IPPROTO_IPV6:
 1456                 if (m->m_pkthdr.len < off + sizeof(ip6))
 1457                         return -1;
 1458                 m_copydata(m, off, sizeof(ip6), (caddr_t)&ip6);
 1459                 if (nxtp)
 1460                         *nxtp = ip6.ip6_nxt;
 1461                 off += sizeof(ip6);
 1462                 return off;
 1463 
 1464         case IPPROTO_FRAGMENT:
 1465                 /*
 1466                  * terminate parsing if it is not the first fragment,
 1467                  * it does not make sense to parse through it.
 1468                  */
 1469                 if (m->m_pkthdr.len < off + sizeof(fh))
 1470                         return -1;
 1471                 m_copydata(m, off, sizeof(fh), (caddr_t)&fh);
 1472                 /* IP6F_OFF_MASK = 0xfff8(BigEndian), 0xf8ff(LittleEndian) */
 1473                 if (fh.ip6f_offlg & IP6F_OFF_MASK)
 1474                         return -1;
 1475                 if (nxtp)
 1476                         *nxtp = fh.ip6f_nxt;
 1477                 off += sizeof(struct ip6_frag);
 1478                 return off;
 1479 
 1480         case IPPROTO_AH:
 1481                 if (m->m_pkthdr.len < off + sizeof(ip6e))
 1482                         return -1;
 1483                 m_copydata(m, off, sizeof(ip6e), (caddr_t)&ip6e);
 1484                 if (nxtp)
 1485                         *nxtp = ip6e.ip6e_nxt;
 1486                 off += (ip6e.ip6e_len + 2) << 2;
 1487                 return off;
 1488 
 1489         case IPPROTO_HOPOPTS:
 1490         case IPPROTO_ROUTING:
 1491         case IPPROTO_DSTOPTS:
 1492                 if (m->m_pkthdr.len < off + sizeof(ip6e))
 1493                         return -1;
 1494                 m_copydata(m, off, sizeof(ip6e), (caddr_t)&ip6e);
 1495                 if (nxtp)
 1496                         *nxtp = ip6e.ip6e_nxt;
 1497                 off += (ip6e.ip6e_len + 1) << 3;
 1498                 return off;
 1499 
 1500         case IPPROTO_NONE:
 1501         case IPPROTO_ESP:
 1502         case IPPROTO_IPCOMP:
 1503                 /* give up */
 1504                 return -1;
 1505 
 1506         default:
 1507                 return -1;
 1508         }
 1509 
 1510         return -1;
 1511 }
 1512 
 1513 /*
 1514  * get offset for the last header in the chain.  m will be kept untainted.
 1515  */
 1516 int
 1517 ip6_lasthdr(struct mbuf *m, int off, int proto, int *nxtp)
 1518 {
 1519         int newoff;
 1520         int nxt;
 1521 
 1522         if (!nxtp) {
 1523                 nxt = -1;
 1524                 nxtp = &nxt;
 1525         }
 1526         while (1) {
 1527                 newoff = ip6_nexthdr(m, off, proto, nxtp);
 1528                 if (newoff < 0)
 1529                         return off;
 1530                 else if (newoff < off)
 1531                         return -1;      /* invalid */
 1532                 else if (newoff == off)
 1533                         return newoff;
 1534 
 1535                 off = newoff;
 1536                 proto = *nxtp;
 1537         }
 1538 }
 1539 
 1540 struct ip6aux *
 1541 ip6_addaux(struct mbuf *m)
 1542 {
 1543         struct m_tag *mtag;
 1544 
 1545         mtag = m_tag_find(m, PACKET_TAG_IPV6_INPUT, NULL);
 1546         if (!mtag) {
 1547                 mtag = m_tag_get(PACKET_TAG_IPV6_INPUT, sizeof(struct ip6aux),
 1548                     M_NOWAIT);
 1549                 if (mtag) {
 1550                         m_tag_prepend(m, mtag);
 1551                         bzero(mtag + 1, sizeof(struct ip6aux));
 1552                 }
 1553         }
 1554         return mtag ? (struct ip6aux *)(mtag + 1) : NULL;
 1555 }
 1556 
 1557 struct ip6aux *
 1558 ip6_findaux(struct mbuf *m)
 1559 {
 1560         struct m_tag *mtag;
 1561 
 1562         mtag = m_tag_find(m, PACKET_TAG_IPV6_INPUT, NULL);
 1563         return mtag ? (struct ip6aux *)(mtag + 1) : NULL;
 1564 }
 1565 
 1566 void
 1567 ip6_delaux(struct mbuf *m)
 1568 {
 1569         struct m_tag *mtag;
 1570 
 1571         mtag = m_tag_find(m, PACKET_TAG_IPV6_INPUT, NULL);
 1572         if (mtag)
 1573                 m_tag_delete(m, mtag);
 1574 }
 1575 
 1576 /*
 1577  * System control for IP6
 1578  */
 1579 
 1580 u_char  inet6ctlerrmap[PRC_NCMDS] = {
 1581         0,              0,              0,              0,
 1582         0,              EMSGSIZE,       EHOSTDOWN,      EHOSTUNREACH,
 1583         EHOSTUNREACH,   EHOSTUNREACH,   ECONNREFUSED,   ECONNREFUSED,
 1584         EMSGSIZE,       EHOSTUNREACH,   0,              0,
 1585         0,              0,              0,              0,
 1586         ENOPROTOOPT
 1587 };

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