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 /*      $FreeBSD: releng/5.0/sys/netinet6/ip6_input.c 105199 2002-10-16 02:25:05Z sam $ */
    2 /*      $KAME: ip6_input.c,v 1.259 2002/01/21 04:58:09 jinmei Exp $     */
    3 
    4 /*
    5  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
    6  * All rights reserved.
    7  *
    8  * Redistribution and use in source and binary forms, with or without
    9  * modification, are permitted provided that the following conditions
   10  * are met:
   11  * 1. Redistributions of source code must retain the above copyright
   12  *    notice, this list of conditions and the following disclaimer.
   13  * 2. Redistributions in binary form must reproduce the above copyright
   14  *    notice, this list of conditions and the following disclaimer in the
   15  *    documentation and/or other materials provided with the distribution.
   16  * 3. Neither the name of the project nor the names of its contributors
   17  *    may be used to endorse or promote products derived from this software
   18  *    without specific prior written permission.
   19  *
   20  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
   21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
   24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   30  * SUCH DAMAGE.
   31  */
   32 
   33 /*
   34  * Copyright (c) 1982, 1986, 1988, 1993
   35  *      The Regents of the University of California.  All rights reserved.
   36  *
   37  * Redistribution and use in source and binary forms, with or without
   38  * modification, are permitted provided that the following conditions
   39  * are met:
   40  * 1. Redistributions of source code must retain the above copyright
   41  *    notice, this list of conditions and the following disclaimer.
   42  * 2. Redistributions in binary form must reproduce the above copyright
   43  *    notice, this list of conditions and the following disclaimer in the
   44  *    documentation and/or other materials provided with the distribution.
   45  * 3. All advertising materials mentioning features or use of this software
   46  *    must display the following acknowledgement:
   47  *      This product includes software developed by the University of
   48  *      California, Berkeley and its contributors.
   49  * 4. Neither the name of the University nor the names of its contributors
   50  *    may be used to endorse or promote products derived from this software
   51  *    without specific prior written permission.
   52  *
   53  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   54  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   55  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   56  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   57  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   58  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   59  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   60  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   61  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   62  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   63  * SUCH DAMAGE.
   64  *
   65  *      @(#)ip_input.c  8.2 (Berkeley) 1/4/94
   66  */
   67 
   68 #include "opt_ip6fw.h"
   69 #include "opt_inet.h"
   70 #include "opt_inet6.h"
   71 #include "opt_ipsec.h"
   72 #include "opt_pfil_hooks.h"
   73 
   74 #include <sys/param.h>
   75 #include <sys/systm.h>
   76 #include <sys/malloc.h>
   77 #include <sys/mbuf.h>
   78 #include <sys/proc.h>
   79 #include <sys/domain.h>
   80 #include <sys/protosw.h>
   81 #include <sys/socket.h>
   82 #include <sys/socketvar.h>
   83 #include <sys/errno.h>
   84 #include <sys/time.h>
   85 #include <sys/kernel.h>
   86 #include <sys/syslog.h>
   87 
   88 #include <net/if.h>
   89 #include <net/if_types.h>
   90 #include <net/if_dl.h>
   91 #include <net/route.h>
   92 #include <net/netisr.h>
   93 #include <net/intrq.h>
   94 #ifdef PFIL_HOOKS
   95 #include <net/pfil.h>
   96 #endif
   97 
   98 #include <netinet/in.h>
   99 #include <netinet/in_systm.h>
  100 #ifdef INET
  101 #include <netinet/ip.h>
  102 #include <netinet/ip_icmp.h>
  103 #endif /* INET */
  104 #include <netinet/ip6.h>
  105 #include <netinet6/in6_var.h>
  106 #include <netinet6/ip6_var.h>
  107 #include <netinet/in_pcb.h>
  108 #include <netinet/icmp6.h>
  109 #include <netinet6/in6_ifattach.h>
  110 #include <netinet6/nd6.h>
  111 #include <netinet6/in6_prefix.h>
  112 
  113 #ifdef IPSEC
  114 #include <netinet6/ipsec.h>
  115 #ifdef INET6
  116 #include <netinet6/ipsec6.h>
  117 #endif
  118 #endif
  119 
  120 #ifdef FAST_IPSEC
  121 #include <netipsec/ipsec.h>
  122 #include <netipsec/ipsec6.h>
  123 #define IPSEC
  124 #endif /* FAST_IPSEC */
  125 
  126 #include <netinet6/ip6_fw.h>
  127 
  128 #include <netinet6/ip6protosw.h>
  129 
  130 #include <net/net_osdep.h>
  131 
  132 extern struct domain inet6domain;
  133 
  134 u_char ip6_protox[IPPROTO_MAX];
  135 static int ip6qmaxlen = IFQ_MAXLEN;
  136 struct in6_ifaddr *in6_ifaddr;
  137 
  138 extern struct callout in6_tmpaddrtimer_ch;
  139 
  140 int ip6_forward_srcrt;                  /* XXX */
  141 int ip6_sourcecheck;                    /* XXX */
  142 int ip6_sourcecheck_interval;           /* XXX */
  143 
  144 int ip6_ours_check_algorithm;
  145 
  146 
  147 /* firewall hooks */
  148 ip6_fw_chk_t *ip6_fw_chk_ptr;
  149 ip6_fw_ctl_t *ip6_fw_ctl_ptr;
  150 int ip6_fw_enable = 1;
  151 
  152 struct ip6stat ip6stat;
  153 
  154 static void ip6_init2 __P((void *));
  155 static struct ip6aux *ip6_setdstifaddr __P((struct mbuf *, struct in6_ifaddr *));
  156 static int ip6_hopopts_input __P((u_int32_t *, u_int32_t *, struct mbuf **, int *));
  157 #ifdef PULLDOWN_TEST
  158 static struct mbuf *ip6_pullexthdr __P((struct mbuf *, size_t, int));
  159 #endif
  160 
  161 
  162 /*
  163  * IP6 initialization: fill in IP6 protocol switch table.
  164  * All protocols not implemented in kernel go to raw IP6 protocol handler.
  165  */
  166 void
  167 ip6_init()
  168 {
  169         struct ip6protosw *pr;
  170         int i;
  171         struct timeval tv;
  172 
  173 #ifdef DIAGNOSTIC
  174         if (sizeof(struct protosw) != sizeof(struct ip6protosw))
  175                 panic("sizeof(protosw) != sizeof(ip6protosw)");
  176 #endif
  177         pr = (struct ip6protosw *)pffindproto(PF_INET6, IPPROTO_RAW, SOCK_RAW);
  178         if (pr == 0)
  179                 panic("ip6_init");
  180         for (i = 0; i < IPPROTO_MAX; i++)
  181                 ip6_protox[i] = pr - inet6sw;
  182         for (pr = (struct ip6protosw *)inet6domain.dom_protosw;
  183             pr < (struct ip6protosw *)inet6domain.dom_protoswNPROTOSW; pr++)
  184                 if (pr->pr_domain->dom_family == PF_INET6 &&
  185                     pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW)
  186                         ip6_protox[pr->pr_protocol] = pr - inet6sw;
  187         ip6intrq.ifq_maxlen = ip6qmaxlen;
  188         mtx_init(&ip6intrq.ifq_mtx, "ip6_inq", NULL, MTX_DEF);
  189         ip6intrq_present = 1;
  190         register_netisr(NETISR_IPV6, ip6intr);
  191         nd6_init();
  192         frag6_init();
  193         /*
  194          * in many cases, random() here does NOT return random number
  195          * as initialization during bootstrap time occur in fixed order.
  196          */
  197         microtime(&tv);
  198         ip6_flow_seq = random() ^ tv.tv_usec;
  199         microtime(&tv);
  200         ip6_desync_factor = (random() ^ tv.tv_usec) % MAX_TEMP_DESYNC_FACTOR;
  201 }
  202 
  203 static void
  204 ip6_init2(dummy)
  205         void *dummy;
  206 {
  207 
  208         /*
  209          * to route local address of p2p link to loopback,
  210          * assign loopback address first.
  211          */
  212         in6_ifattach(&loif[0], NULL);
  213 
  214         /* nd6_timer_init */
  215         callout_init(&nd6_timer_ch, 0);
  216         callout_reset(&nd6_timer_ch, hz, nd6_timer, NULL);
  217 
  218         /* router renumbering prefix list maintenance */
  219         callout_init(&in6_rr_timer_ch, 0);
  220         callout_reset(&in6_rr_timer_ch, hz, in6_rr_timer, NULL);
  221 
  222         /* timer for regeneranation of temporary addresses randomize ID */
  223         callout_reset(&in6_tmpaddrtimer_ch,
  224                       (ip6_temp_preferred_lifetime - ip6_desync_factor -
  225                        ip6_temp_regen_advance) * hz,
  226                       in6_tmpaddrtimer, NULL);
  227 }
  228 
  229 /* cheat */
  230 /* This must be after route_init(), which is now SI_ORDER_THIRD */
  231 SYSINIT(netinet6init2, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, ip6_init2, NULL);
  232 
  233 /*
  234  * IP6 input interrupt handling. Just pass the packet to ip6_input.
  235  */
  236 void
  237 ip6intr()
  238 {
  239         int s;
  240         struct mbuf *m;
  241 
  242         for (;;) {
  243                 s = splimp();
  244                 IF_DEQUEUE(&ip6intrq, m);
  245                 splx(s);
  246                 if (m == 0)
  247                         return;
  248                 ip6_input(m);
  249         }
  250 }
  251 
  252 extern struct   route_in6 ip6_forward_rt;
  253 
  254 void
  255 ip6_input(m)
  256         struct mbuf *m;
  257 {
  258         struct ip6_hdr *ip6;
  259         int off = sizeof(struct ip6_hdr), nest;
  260         u_int32_t plen;
  261         u_int32_t rtalert = ~0;
  262         int nxt, ours = 0;
  263         struct ifnet *deliverifp = NULL;
  264 #ifdef  PFIL_HOOKS
  265         struct packet_filter_hook *pfh;
  266         struct mbuf *m0;
  267         int rv;
  268 #endif  /* PFIL_HOOKS */
  269 
  270 #ifdef IPSEC
  271         /*
  272          * should the inner packet be considered authentic?
  273          * see comment in ah4_input().
  274          */
  275         if (m) {
  276                 m->m_flags &= ~M_AUTHIPHDR;
  277                 m->m_flags &= ~M_AUTHIPDGM;
  278         }
  279 #endif
  280 
  281         /*
  282          * make sure we don't have onion peering information into m_aux.
  283          */
  284         ip6_delaux(m);
  285 
  286         /*
  287          * mbuf statistics
  288          */
  289         if (m->m_flags & M_EXT) {
  290                 if (m->m_next)
  291                         ip6stat.ip6s_mext2m++;
  292                 else
  293                         ip6stat.ip6s_mext1++;
  294         } else {
  295 #define M2MMAX  (sizeof(ip6stat.ip6s_m2m)/sizeof(ip6stat.ip6s_m2m[0]))
  296                 if (m->m_next) {
  297                         if (m->m_flags & M_LOOP) {
  298                                 ip6stat.ip6s_m2m[loif[0].if_index]++;   /* XXX */
  299                         } else if (m->m_pkthdr.rcvif->if_index < M2MMAX)
  300                                 ip6stat.ip6s_m2m[m->m_pkthdr.rcvif->if_index]++;
  301                         else
  302                                 ip6stat.ip6s_m2m[0]++;
  303                 } else
  304                         ip6stat.ip6s_m1++;
  305 #undef M2MMAX
  306         }
  307 
  308         in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_receive);
  309         ip6stat.ip6s_total++;
  310 
  311 #ifndef PULLDOWN_TEST
  312         /*
  313          * L2 bridge code and some other code can return mbuf chain
  314          * that does not conform to KAME requirement.  too bad.
  315          * XXX: fails to join if interface MTU > MCLBYTES.  jumbogram?
  316          */
  317         if (m && m->m_next != NULL && m->m_pkthdr.len < MCLBYTES) {
  318                 struct mbuf *n;
  319 
  320                 MGETHDR(n, M_DONTWAIT, MT_HEADER);
  321                 if (n)
  322                         M_COPY_PKTHDR(n, m);
  323                 if (n && m->m_pkthdr.len > MHLEN) {
  324                         MCLGET(n, M_DONTWAIT);
  325                         if ((n->m_flags & M_EXT) == 0) {
  326                                 m_freem(n);
  327                                 n = NULL;
  328                         }
  329                 }
  330                 if (n == NULL) {
  331                         m_freem(m);
  332                         return; /*ENOBUFS*/
  333                 }
  334 
  335                 m_copydata(m, 0, m->m_pkthdr.len, mtod(n, caddr_t));
  336                 n->m_len = m->m_pkthdr.len;
  337                 m_freem(m);
  338                 m = n;
  339         }
  340         IP6_EXTHDR_CHECK(m, 0, sizeof(struct ip6_hdr), /*nothing*/);
  341 #endif
  342 
  343         if (m->m_len < sizeof(struct ip6_hdr)) {
  344                 struct ifnet *inifp;
  345                 inifp = m->m_pkthdr.rcvif;
  346                 if ((m = m_pullup(m, sizeof(struct ip6_hdr))) == 0) {
  347                         ip6stat.ip6s_toosmall++;
  348                         in6_ifstat_inc(inifp, ifs6_in_hdrerr);
  349                         return;
  350                 }
  351         }
  352 
  353         ip6 = mtod(m, struct ip6_hdr *);
  354 
  355         if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) {
  356                 ip6stat.ip6s_badvers++;
  357                 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_hdrerr);
  358                 goto bad;
  359         }
  360 
  361 #ifdef PFIL_HOOKS
  362         /*
  363          * Run through list of hooks for input packets.  If there are any
  364          * filters which require that additional packets in the flow are
  365          * not fast-forwarded, they must clear the M_CANFASTFWD flag.
  366          * Note that filters must _never_ set this flag, as another filter
  367          * in the list may have previously cleared it.
  368          */
  369         m0 = m;
  370         pfh = pfil_hook_get(PFIL_IN, &inet6sw[ip6_protox[IPPROTO_IPV6]].pr_pfh);
  371         for (; pfh; pfh = pfh->pfil_link.tqe_next)
  372                 if (pfh->pfil_func) {
  373                         rv = pfh->pfil_func(ip6, sizeof(*ip6),
  374                                             m->m_pkthdr.rcvif, 0, &m0);
  375                         if (rv)
  376                                 return;
  377                         m = m0;
  378                         if (m == NULL)
  379                                 return;
  380                         ip6 = mtod(m, struct ip6_hdr *);
  381                 }
  382 #endif /* PFIL_HOOKS */
  383 
  384         ip6stat.ip6s_nxthist[ip6->ip6_nxt]++;
  385 
  386         /*
  387          * Check with the firewall...
  388          */
  389         if (ip6_fw_enable && ip6_fw_chk_ptr) {
  390                 u_short port = 0;
  391                 /* If ipfw says divert, we have to just drop packet */
  392                 /* use port as a dummy argument */
  393                 if ((*ip6_fw_chk_ptr)(&ip6, NULL, &port, &m)) {
  394                         m_freem(m);
  395                         m = NULL;
  396                 }
  397                 if (!m)
  398                         return;
  399         }
  400 
  401         /*
  402          * Check against address spoofing/corruption.
  403          */
  404         if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_src) ||
  405             IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_dst)) {
  406                 /*
  407                  * XXX: "badscope" is not very suitable for a multicast source.
  408                  */
  409                 ip6stat.ip6s_badscope++;
  410                 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
  411                 goto bad;
  412         }
  413         if ((IN6_IS_ADDR_LOOPBACK(&ip6->ip6_src) ||
  414              IN6_IS_ADDR_LOOPBACK(&ip6->ip6_dst)) &&
  415             (m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) {
  416                 ip6stat.ip6s_badscope++;
  417                 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
  418                 goto bad;
  419         }
  420 
  421         /*
  422          * The following check is not documented in specs.  A malicious
  423          * party may be able to use IPv4 mapped addr to confuse tcp/udp stack
  424          * and bypass security checks (act as if it was from 127.0.0.1 by using
  425          * IPv6 src ::ffff:127.0.0.1).  Be cautious.
  426          *
  427          * This check chokes if we are in an SIIT cloud.  As none of BSDs
  428          * support IPv4-less kernel compilation, we cannot support SIIT
  429          * environment at all.  So, it makes more sense for us to reject any
  430          * malicious packets for non-SIIT environment, than try to do a
  431          * partical support for SIIT environment.
  432          */
  433         if (IN6_IS_ADDR_V4MAPPED(&ip6->ip6_src) ||
  434             IN6_IS_ADDR_V4MAPPED(&ip6->ip6_dst)) {
  435                 ip6stat.ip6s_badscope++;
  436                 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
  437                 goto bad;
  438         }
  439 #if 0
  440         /*
  441          * Reject packets with IPv4 compatible addresses (auto tunnel).
  442          *
  443          * The code forbids auto tunnel relay case in RFC1933 (the check is
  444          * stronger than RFC1933).  We may want to re-enable it if mech-xx
  445          * is revised to forbid relaying case.
  446          */
  447         if (IN6_IS_ADDR_V4COMPAT(&ip6->ip6_src) ||
  448             IN6_IS_ADDR_V4COMPAT(&ip6->ip6_dst)) {
  449                 ip6stat.ip6s_badscope++;
  450                 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
  451                 goto bad;
  452         }
  453 #endif
  454 
  455         /* drop packets if interface ID portion is already filled */
  456         if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) {
  457                 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src) &&
  458                     ip6->ip6_src.s6_addr16[1]) {
  459                         ip6stat.ip6s_badscope++;
  460                         goto bad;
  461                 }
  462                 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst) &&
  463                     ip6->ip6_dst.s6_addr16[1]) {
  464                         ip6stat.ip6s_badscope++;
  465                         goto bad;
  466                 }
  467         }
  468 
  469         if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src))
  470                 ip6->ip6_src.s6_addr16[1]
  471                         = htons(m->m_pkthdr.rcvif->if_index);
  472         if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst))
  473                 ip6->ip6_dst.s6_addr16[1]
  474                         = htons(m->m_pkthdr.rcvif->if_index);
  475 
  476 #if 0 /* this case seems to be unnecessary. (jinmei, 20010401) */
  477         /*
  478          * We use rt->rt_ifp to determine if the address is ours or not.
  479          * If rt_ifp is lo0, the address is ours.
  480          * The problem here is, rt->rt_ifp for fe80::%lo0/64 is set to lo0,
  481          * so any address under fe80::%lo0/64 will be mistakenly considered
  482          * local.  The special case is supplied to handle the case properly
  483          * by actually looking at interface addresses
  484          * (using in6ifa_ifpwithaddr).
  485          */
  486         if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) != 0 &&
  487             IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_dst)) {
  488                 if (!in6ifa_ifpwithaddr(m->m_pkthdr.rcvif, &ip6->ip6_dst)) {
  489                         icmp6_error(m, ICMP6_DST_UNREACH,
  490                             ICMP6_DST_UNREACH_ADDR, 0);
  491                         /* m is already freed */
  492                         return;
  493                 }
  494 
  495                 ours = 1;
  496                 deliverifp = m->m_pkthdr.rcvif;
  497                 goto hbhcheck;
  498         }
  499 #endif
  500 
  501         /*
  502          * Multicast check
  503          */
  504         if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
  505                 struct  in6_multi *in6m = 0;
  506 
  507                 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_mcast);
  508                 /*
  509                  * See if we belong to the destination multicast group on the
  510                  * arrival interface.
  511                  */
  512                 IN6_LOOKUP_MULTI(ip6->ip6_dst, m->m_pkthdr.rcvif, in6m);
  513                 if (in6m)
  514                         ours = 1;
  515                 else if (!ip6_mrouter) {
  516                         ip6stat.ip6s_notmember++;
  517                         ip6stat.ip6s_cantforward++;
  518                         in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
  519                         goto bad;
  520                 }
  521                 deliverifp = m->m_pkthdr.rcvif;
  522                 goto hbhcheck;
  523         }
  524 
  525         /*
  526          *  Unicast check
  527          */
  528         switch (ip6_ours_check_algorithm) {
  529         default:
  530                 /*
  531                  * XXX: I intentionally broke our indentation rule here,
  532                  *      since this switch-case is just for measurement and
  533                  *      therefore should soon be removed.
  534                  */
  535         if (ip6_forward_rt.ro_rt != NULL &&
  536             (ip6_forward_rt.ro_rt->rt_flags & RTF_UP) != 0 && 
  537             IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst,
  538                                &((struct sockaddr_in6 *)(&ip6_forward_rt.ro_dst))->sin6_addr))
  539                 ip6stat.ip6s_forward_cachehit++;
  540         else {
  541                 struct sockaddr_in6 *dst6;
  542 
  543                 if (ip6_forward_rt.ro_rt) {
  544                         /* route is down or destination is different */
  545                         ip6stat.ip6s_forward_cachemiss++;
  546                         RTFREE(ip6_forward_rt.ro_rt);
  547                         ip6_forward_rt.ro_rt = 0;
  548                 }
  549 
  550                 bzero(&ip6_forward_rt.ro_dst, sizeof(struct sockaddr_in6));
  551                 dst6 = (struct sockaddr_in6 *)&ip6_forward_rt.ro_dst;
  552                 dst6->sin6_len = sizeof(struct sockaddr_in6);
  553                 dst6->sin6_family = AF_INET6;
  554                 dst6->sin6_addr = ip6->ip6_dst;
  555 #ifdef SCOPEDROUTING
  556                 ip6_forward_rt.ro_dst.sin6_scope_id =
  557                         in6_addr2scopeid(m->m_pkthdr.rcvif, &ip6->ip6_dst);
  558 #endif
  559 
  560                 rtalloc_ign((struct route *)&ip6_forward_rt, RTF_PRCLONING);
  561         }
  562 
  563 #define rt6_key(r) ((struct sockaddr_in6 *)((r)->rt_nodes->rn_key))
  564 
  565         /*
  566          * Accept the packet if the forwarding interface to the destination
  567          * according to the routing table is the loopback interface,
  568          * unless the associated route has a gateway.
  569          * Note that this approach causes to accept a packet if there is a
  570          * route to the loopback interface for the destination of the packet.
  571          * But we think it's even useful in some situations, e.g. when using
  572          * a special daemon which wants to intercept the packet.
  573          *
  574          * XXX: some OSes automatically make a cloned route for the destination
  575          * of an outgoing packet.  If the outgoing interface of the packet
  576          * is a loopback one, the kernel would consider the packet to be
  577          * accepted, even if we have no such address assinged on the interface.
  578          * We check the cloned flag of the route entry to reject such cases,
  579          * assuming that route entries for our own addresses are not made by
  580          * cloning (it should be true because in6_addloop explicitly installs
  581          * the host route).  However, we might have to do an explicit check
  582          * while it would be less efficient.  Or, should we rather install a
  583          * reject route for such a case?
  584          */
  585         if (ip6_forward_rt.ro_rt &&
  586             (ip6_forward_rt.ro_rt->rt_flags &
  587              (RTF_HOST|RTF_GATEWAY)) == RTF_HOST &&
  588 #ifdef RTF_WASCLONED
  589             !(ip6_forward_rt.ro_rt->rt_flags & RTF_WASCLONED) &&
  590 #endif
  591 #ifdef RTF_CLONED
  592             !(ip6_forward_rt.ro_rt->rt_flags & RTF_CLONED) &&
  593 #endif
  594 #if 0
  595             /*
  596              * The check below is redundant since the comparison of
  597              * the destination and the key of the rtentry has
  598              * already done through looking up the routing table.
  599              */
  600             IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst,
  601                                 &rt6_key(ip6_forward_rt.ro_rt)->sin6_addr)
  602 #endif
  603             ip6_forward_rt.ro_rt->rt_ifp->if_type == IFT_LOOP) {
  604                 struct in6_ifaddr *ia6 =
  605                         (struct in6_ifaddr *)ip6_forward_rt.ro_rt->rt_ifa;
  606 
  607                 /*
  608                  * record address information into m_aux.
  609                  */
  610                 (void)ip6_setdstifaddr(m, ia6);
  611 
  612                 /*
  613                  * packets to a tentative, duplicated, or somehow invalid
  614                  * address must not be accepted.
  615                  */
  616                 if (!(ia6->ia6_flags & IN6_IFF_NOTREADY)) {
  617                         /* this address is ready */
  618                         ours = 1;
  619                         deliverifp = ia6->ia_ifp;       /* correct? */
  620                         /* Count the packet in the ip address stats */
  621                         ia6->ia_ifa.if_ipackets++;
  622                         ia6->ia_ifa.if_ibytes += m->m_pkthdr.len;
  623                         goto hbhcheck;
  624                 } else {
  625                         /* address is not ready, so discard the packet. */
  626                         nd6log((LOG_INFO,
  627                             "ip6_input: packet to an unready address %s->%s\n",
  628                             ip6_sprintf(&ip6->ip6_src),
  629                             ip6_sprintf(&ip6->ip6_dst)));
  630 
  631                         goto bad;
  632                 }
  633         }
  634         } /* XXX indentation (see above) */
  635 
  636         /*
  637          * FAITH(Firewall Aided Internet Translator)
  638          */
  639         if (ip6_keepfaith) {
  640                 if (ip6_forward_rt.ro_rt && ip6_forward_rt.ro_rt->rt_ifp
  641                  && ip6_forward_rt.ro_rt->rt_ifp->if_type == IFT_FAITH) {
  642                         /* XXX do we need more sanity checks? */
  643                         ours = 1;
  644                         deliverifp = ip6_forward_rt.ro_rt->rt_ifp; /* faith */
  645                         goto hbhcheck;
  646                 }
  647         }
  648 
  649         /*
  650          * Now there is no reason to process the packet if it's not our own
  651          * and we're not a router.
  652          */
  653         if (!ip6_forwarding) {
  654                 ip6stat.ip6s_cantforward++;
  655                 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
  656                 goto bad;
  657         }
  658 
  659   hbhcheck:
  660         /*
  661          * record address information into m_aux, if we don't have one yet.
  662          * note that we are unable to record it, if the address is not listed
  663          * as our interface address (e.g. multicast addresses, addresses
  664          * within FAITH prefixes and such).
  665          */
  666         if (deliverifp && !ip6_getdstifaddr(m)) {
  667                 struct in6_ifaddr *ia6;
  668 
  669                 ia6 = in6_ifawithifp(deliverifp, &ip6->ip6_dst);
  670                 if (ia6) {
  671                         if (!ip6_setdstifaddr(m, ia6)) {
  672                                 /*
  673                                  * XXX maybe we should drop the packet here,
  674                                  * as we could not provide enough information
  675                                  * to the upper layers.
  676                                  */
  677                         }
  678                 }
  679         }
  680 
  681         /*
  682          * Process Hop-by-Hop options header if it's contained.
  683          * m may be modified in ip6_hopopts_input().
  684          * If a JumboPayload option is included, plen will also be modified.
  685          */
  686         plen = (u_int32_t)ntohs(ip6->ip6_plen);
  687         if (ip6->ip6_nxt == IPPROTO_HOPOPTS) {
  688                 struct ip6_hbh *hbh;
  689 
  690                 if (ip6_hopopts_input(&plen, &rtalert, &m, &off)) {
  691 #if 0   /*touches NULL pointer*/
  692                         in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
  693 #endif
  694                         return; /* m have already been freed */
  695                 }
  696 
  697                 /* adjust pointer */
  698                 ip6 = mtod(m, struct ip6_hdr *);
  699 
  700                 /*
  701                  * if the payload length field is 0 and the next header field
  702                  * indicates Hop-by-Hop Options header, then a Jumbo Payload
  703                  * option MUST be included.
  704                  */
  705                 if (ip6->ip6_plen == 0 && plen == 0) {
  706                         /*
  707                          * Note that if a valid jumbo payload option is
  708                          * contained, ip6_hoptops_input() must set a valid
  709                          * (non-zero) payload length to the variable plen. 
  710                          */
  711                         ip6stat.ip6s_badoptions++;
  712                         in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
  713                         in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_hdrerr);
  714                         icmp6_error(m, ICMP6_PARAM_PROB,
  715                                     ICMP6_PARAMPROB_HEADER,
  716                                     (caddr_t)&ip6->ip6_plen - (caddr_t)ip6);
  717                         return;
  718                 }
  719 #ifndef PULLDOWN_TEST
  720                 /* ip6_hopopts_input() ensures that mbuf is contiguous */
  721                 hbh = (struct ip6_hbh *)(ip6 + 1);
  722 #else
  723                 IP6_EXTHDR_GET(hbh, struct ip6_hbh *, m, sizeof(struct ip6_hdr),
  724                         sizeof(struct ip6_hbh));
  725                 if (hbh == NULL) {
  726                         ip6stat.ip6s_tooshort++;
  727                         return;
  728                 }
  729 #endif
  730                 nxt = hbh->ip6h_nxt;
  731 
  732                 /*
  733                  * accept the packet if a router alert option is included
  734                  * and we act as an IPv6 router.
  735                  */
  736                 if (rtalert != ~0 && ip6_forwarding)
  737                         ours = 1;
  738         } else
  739                 nxt = ip6->ip6_nxt;
  740 
  741         /*
  742          * Check that the amount of data in the buffers
  743          * is as at least much as the IPv6 header would have us expect.
  744          * Trim mbufs if longer than we expect.
  745          * Drop packet if shorter than we expect.
  746          */
  747         if (m->m_pkthdr.len - sizeof(struct ip6_hdr) < plen) {
  748                 ip6stat.ip6s_tooshort++;
  749                 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_truncated);
  750                 goto bad;
  751         }
  752         if (m->m_pkthdr.len > sizeof(struct ip6_hdr) + plen) {
  753                 if (m->m_len == m->m_pkthdr.len) {
  754                         m->m_len = sizeof(struct ip6_hdr) + plen;
  755                         m->m_pkthdr.len = sizeof(struct ip6_hdr) + plen;
  756                 } else
  757                         m_adj(m, sizeof(struct ip6_hdr) + plen - m->m_pkthdr.len);
  758         }
  759 
  760         /*
  761          * Forward if desirable.
  762          */
  763         if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
  764                 /*
  765                  * If we are acting as a multicast router, all
  766                  * incoming multicast packets are passed to the
  767                  * kernel-level multicast forwarding function.
  768                  * The packet is returned (relatively) intact; if
  769                  * ip6_mforward() returns a non-zero value, the packet
  770                  * must be discarded, else it may be accepted below.
  771                  */
  772                 if (ip6_mrouter && ip6_mforward(ip6, m->m_pkthdr.rcvif, m)) {
  773                         ip6stat.ip6s_cantforward++;
  774                         m_freem(m);
  775                         return;
  776                 }
  777                 if (!ours) {
  778                         m_freem(m);
  779                         return;
  780                 }
  781         } else if (!ours) {
  782                 ip6_forward(m, 0);
  783                 return;
  784         }       
  785 
  786         ip6 = mtod(m, struct ip6_hdr *);
  787 
  788         /*
  789          * Malicious party may be able to use IPv4 mapped addr to confuse
  790          * tcp/udp stack and bypass security checks (act as if it was from
  791          * 127.0.0.1 by using IPv6 src ::ffff:127.0.0.1).  Be cautious.
  792          *
  793          * For SIIT end node behavior, you may want to disable the check.
  794          * However, you will  become vulnerable to attacks using IPv4 mapped
  795          * source.
  796          */
  797         if (IN6_IS_ADDR_V4MAPPED(&ip6->ip6_src) ||
  798             IN6_IS_ADDR_V4MAPPED(&ip6->ip6_dst)) {
  799                 ip6stat.ip6s_badscope++;
  800                 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
  801                 goto bad;
  802         }
  803 
  804         /*
  805          * Tell launch routine the next header
  806          */
  807         ip6stat.ip6s_delivered++;
  808         in6_ifstat_inc(deliverifp, ifs6_in_deliver);
  809         nest = 0;
  810 
  811         while (nxt != IPPROTO_DONE) {
  812                 if (ip6_hdrnestlimit && (++nest > ip6_hdrnestlimit)) {
  813                         ip6stat.ip6s_toomanyhdr++;
  814                         goto bad;
  815                 }
  816 
  817                 /*
  818                  * protection against faulty packet - there should be
  819                  * more sanity checks in header chain processing.
  820                  */
  821                 if (m->m_pkthdr.len < off) {
  822                         ip6stat.ip6s_tooshort++;
  823                         in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_truncated);
  824                         goto bad;
  825                 }
  826 
  827 #if 0
  828                 /*
  829                  * do we need to do it for every header?  yeah, other
  830                  * functions can play with it (like re-allocate and copy).
  831                  */
  832                 mhist = ip6_addaux(m);
  833                 if (mhist && M_TRAILINGSPACE(mhist) >= sizeof(nxt)) {
  834                         hist = mtod(mhist, caddr_t) + mhist->m_len;
  835                         bcopy(&nxt, hist, sizeof(nxt));
  836                         mhist->m_len += sizeof(nxt);
  837                 } else {
  838                         ip6stat.ip6s_toomanyhdr++;
  839                         goto bad;
  840                 }
  841 #endif
  842 
  843 #ifdef IPSEC
  844                 /*
  845                  * enforce IPsec policy checking if we are seeing last header.
  846                  * note that we do not visit this with protocols with pcb layer
  847                  * code - like udp/tcp/raw ip.
  848                  */
  849                 if ((inet6sw[ip6_protox[nxt]].pr_flags & PR_LASTHDR) != 0 &&
  850                     ipsec6_in_reject(m, NULL)) {
  851                         ipsec6stat.in_polvio++;
  852                         goto bad;
  853                 }
  854 #endif
  855 
  856                 nxt = (*inet6sw[ip6_protox[nxt]].pr_input)(&m, &off, nxt);
  857         }
  858         return;
  859  bad:
  860         m_freem(m);
  861 }
  862 
  863 /*
  864  * set/grab in6_ifaddr correspond to IPv6 destination address.
  865  * XXX backward compatibility wrapper
  866  */
  867 static struct ip6aux *
  868 ip6_setdstifaddr(m, ia6)
  869         struct mbuf *m;
  870         struct in6_ifaddr *ia6;
  871 {
  872         struct ip6aux *n;
  873 
  874         n = ip6_addaux(m);
  875         if (n)
  876                 n->ip6a_dstia6 = ia6;
  877         return n;       /* NULL if failed to set */
  878 }
  879 
  880 struct in6_ifaddr *
  881 ip6_getdstifaddr(m)
  882         struct mbuf *m;
  883 {
  884         struct ip6aux *n;
  885 
  886         n = ip6_findaux(m);
  887         if (n)
  888                 return n->ip6a_dstia6;
  889         else
  890                 return NULL;
  891 }
  892 
  893 /*
  894  * Hop-by-Hop options header processing. If a valid jumbo payload option is
  895  * included, the real payload length will be stored in plenp.
  896  */
  897 static int
  898 ip6_hopopts_input(plenp, rtalertp, mp, offp)
  899         u_int32_t *plenp;
  900         u_int32_t *rtalertp;    /* XXX: should be stored more smart way */
  901         struct mbuf **mp;
  902         int *offp;
  903 {
  904         struct mbuf *m = *mp;
  905         int off = *offp, hbhlen;
  906         struct ip6_hbh *hbh;
  907         u_int8_t *opt;
  908 
  909         /* validation of the length of the header */
  910 #ifndef PULLDOWN_TEST
  911         IP6_EXTHDR_CHECK(m, off, sizeof(*hbh), -1);
  912         hbh = (struct ip6_hbh *)(mtod(m, caddr_t) + off);
  913         hbhlen = (hbh->ip6h_len + 1) << 3;
  914 
  915         IP6_EXTHDR_CHECK(m, off, hbhlen, -1);
  916         hbh = (struct ip6_hbh *)(mtod(m, caddr_t) + off);
  917 #else
  918         IP6_EXTHDR_GET(hbh, struct ip6_hbh *, m,
  919                 sizeof(struct ip6_hdr), sizeof(struct ip6_hbh));
  920         if (hbh == NULL) {
  921                 ip6stat.ip6s_tooshort++;
  922                 return -1;
  923         }
  924         hbhlen = (hbh->ip6h_len + 1) << 3;
  925         IP6_EXTHDR_GET(hbh, struct ip6_hbh *, m, sizeof(struct ip6_hdr),
  926                 hbhlen);
  927         if (hbh == NULL) {
  928                 ip6stat.ip6s_tooshort++;
  929                 return -1;
  930         }
  931 #endif
  932         off += hbhlen;
  933         hbhlen -= sizeof(struct ip6_hbh);
  934         opt = (u_int8_t *)hbh + sizeof(struct ip6_hbh);
  935 
  936         if (ip6_process_hopopts(m, (u_int8_t *)hbh + sizeof(struct ip6_hbh),
  937                                 hbhlen, rtalertp, plenp) < 0)
  938                 return(-1);
  939 
  940         *offp = off;
  941         *mp = m;
  942         return(0);
  943 }
  944 
  945 /*
  946  * Search header for all Hop-by-hop options and process each option.
  947  * This function is separate from ip6_hopopts_input() in order to
  948  * handle a case where the sending node itself process its hop-by-hop
  949  * options header. In such a case, the function is called from ip6_output().
  950  *
  951  * The function assumes that hbh header is located right after the IPv6 header
  952  * (RFC2460 p7), opthead is pointer into data content in m, and opthead to
  953  * opthead + hbhlen is located in continuous memory region.
  954  */
  955 int
  956 ip6_process_hopopts(m, opthead, hbhlen, rtalertp, plenp)
  957         struct mbuf *m;
  958         u_int8_t *opthead;
  959         int hbhlen;
  960         u_int32_t *rtalertp;
  961         u_int32_t *plenp;
  962 {
  963         struct ip6_hdr *ip6;
  964         int optlen = 0;
  965         u_int8_t *opt = opthead;
  966         u_int16_t rtalert_val;
  967         u_int32_t jumboplen;
  968         const int erroff = sizeof(struct ip6_hdr) + sizeof(struct ip6_hbh);
  969 
  970         for (; hbhlen > 0; hbhlen -= optlen, opt += optlen) {
  971                 switch (*opt) {
  972                 case IP6OPT_PAD1:
  973                         optlen = 1;
  974                         break;
  975                 case IP6OPT_PADN:
  976                         if (hbhlen < IP6OPT_MINLEN) {
  977                                 ip6stat.ip6s_toosmall++;
  978                                 goto bad;
  979                         }
  980                         optlen = *(opt + 1) + 2;
  981                         break;
  982                 case IP6OPT_RTALERT:
  983                         /* XXX may need check for alignment */
  984                         if (hbhlen < IP6OPT_RTALERT_LEN) {
  985                                 ip6stat.ip6s_toosmall++;
  986                                 goto bad;
  987                         }
  988                         if (*(opt + 1) != IP6OPT_RTALERT_LEN - 2) {
  989                                 /* XXX stat */
  990                                 icmp6_error(m, ICMP6_PARAM_PROB,
  991                                             ICMP6_PARAMPROB_HEADER,
  992                                             erroff + opt + 1 - opthead);
  993                                 return(-1);
  994                         }
  995                         optlen = IP6OPT_RTALERT_LEN;
  996                         bcopy((caddr_t)(opt + 2), (caddr_t)&rtalert_val, 2);
  997                         *rtalertp = ntohs(rtalert_val);
  998                         break;
  999                 case IP6OPT_JUMBO:
 1000                         /* XXX may need check for alignment */
 1001                         if (hbhlen < IP6OPT_JUMBO_LEN) {
 1002                                 ip6stat.ip6s_toosmall++;
 1003                                 goto bad;
 1004                         }
 1005                         if (*(opt + 1) != IP6OPT_JUMBO_LEN - 2) {
 1006                                 /* XXX stat */
 1007                                 icmp6_error(m, ICMP6_PARAM_PROB,
 1008                                             ICMP6_PARAMPROB_HEADER,
 1009                                             erroff + opt + 1 - opthead);
 1010                                 return(-1);
 1011                         }
 1012                         optlen = IP6OPT_JUMBO_LEN;
 1013 
 1014                         /*
 1015                          * IPv6 packets that have non 0 payload length
 1016                          * must not contain a jumbo payload option.
 1017                          */
 1018                         ip6 = mtod(m, struct ip6_hdr *);
 1019                         if (ip6->ip6_plen) {
 1020                                 ip6stat.ip6s_badoptions++;
 1021                                 icmp6_error(m, ICMP6_PARAM_PROB,
 1022                                             ICMP6_PARAMPROB_HEADER,
 1023                                             erroff + opt - opthead);
 1024                                 return(-1);
 1025                         }
 1026 
 1027                         /*
 1028                          * We may see jumbolen in unaligned location, so
 1029                          * we'd need to perform bcopy().
 1030                          */
 1031                         bcopy(opt + 2, &jumboplen, sizeof(jumboplen));
 1032                         jumboplen = (u_int32_t)htonl(jumboplen);
 1033 
 1034 #if 1
 1035                         /*
 1036                          * if there are multiple jumbo payload options,
 1037                          * *plenp will be non-zero and the packet will be
 1038                          * rejected.
 1039                          * the behavior may need some debate in ipngwg -
 1040                          * multiple options does not make sense, however,
 1041                          * there's no explicit mention in specification.
 1042                          */
 1043                         if (*plenp != 0) {
 1044                                 ip6stat.ip6s_badoptions++;
 1045                                 icmp6_error(m, ICMP6_PARAM_PROB,
 1046                                             ICMP6_PARAMPROB_HEADER,
 1047                                             erroff + opt + 2 - opthead);
 1048                                 return(-1);
 1049                         }
 1050 #endif
 1051 
 1052                         /*
 1053                          * jumbo payload length must be larger than 65535.
 1054                          */
 1055                         if (jumboplen <= IPV6_MAXPACKET) {
 1056                                 ip6stat.ip6s_badoptions++;
 1057                                 icmp6_error(m, ICMP6_PARAM_PROB,
 1058                                             ICMP6_PARAMPROB_HEADER,
 1059                                             erroff + opt + 2 - opthead);
 1060                                 return(-1);
 1061                         }
 1062                         *plenp = jumboplen;
 1063 
 1064                         break;
 1065                 default:                /* unknown option */
 1066                         if (hbhlen < IP6OPT_MINLEN) {
 1067                                 ip6stat.ip6s_toosmall++;
 1068                                 goto bad;
 1069                         }
 1070                         optlen = ip6_unknown_opt(opt, m,
 1071                             erroff + opt - opthead);
 1072                         if (optlen == -1)
 1073                                 return(-1);
 1074                         optlen += 2;
 1075                         break;
 1076                 }
 1077         }
 1078 
 1079         return(0);
 1080 
 1081   bad:
 1082         m_freem(m);
 1083         return(-1);
 1084 }
 1085 
 1086 /*
 1087  * Unknown option processing.
 1088  * The third argument `off' is the offset from the IPv6 header to the option,
 1089  * which is necessary if the IPv6 header the and option header and IPv6 header
 1090  * is not continuous in order to return an ICMPv6 error.
 1091  */
 1092 int
 1093 ip6_unknown_opt(optp, m, off)
 1094         u_int8_t *optp;
 1095         struct mbuf *m;
 1096         int off;
 1097 {
 1098         struct ip6_hdr *ip6;
 1099 
 1100         switch (IP6OPT_TYPE(*optp)) {
 1101         case IP6OPT_TYPE_SKIP: /* ignore the option */
 1102                 return((int)*(optp + 1));
 1103         case IP6OPT_TYPE_DISCARD:       /* silently discard */
 1104                 m_freem(m);
 1105                 return(-1);
 1106         case IP6OPT_TYPE_FORCEICMP: /* send ICMP even if multicasted */
 1107                 ip6stat.ip6s_badoptions++;
 1108                 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_OPTION, off);
 1109                 return(-1);
 1110         case IP6OPT_TYPE_ICMP: /* send ICMP if not multicasted */
 1111                 ip6stat.ip6s_badoptions++;
 1112                 ip6 = mtod(m, struct ip6_hdr *);
 1113                 if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) ||
 1114                     (m->m_flags & (M_BCAST|M_MCAST)))
 1115                         m_freem(m);
 1116                 else
 1117                         icmp6_error(m, ICMP6_PARAM_PROB,
 1118                                     ICMP6_PARAMPROB_OPTION, off);
 1119                 return(-1);
 1120         }
 1121 
 1122         m_freem(m);             /* XXX: NOTREACHED */
 1123         return(-1);
 1124 }
 1125 
 1126 /*
 1127  * Create the "control" list for this pcb.
 1128  * The function will not modify mbuf chain at all.
 1129  *
 1130  * with KAME mbuf chain restriction:
 1131  * The routine will be called from upper layer handlers like tcp6_input().
 1132  * Thus the routine assumes that the caller (tcp6_input) have already
 1133  * called IP6_EXTHDR_CHECK() and all the extension headers are located in the
 1134  * very first mbuf on the mbuf chain.
 1135  */
 1136 void
 1137 ip6_savecontrol(in6p, mp, ip6, m)
 1138         struct inpcb *in6p;
 1139         struct mbuf **mp;
 1140         struct ip6_hdr *ip6;
 1141         struct mbuf *m;
 1142 {
 1143 #if __FreeBSD_version >= 500000
 1144         struct thread *td = curthread;  /* XXX */
 1145 #else
 1146         struct proc *td = curproc;      /* XXX */
 1147 #endif
 1148         int privileged = 0;
 1149         int rthdr_exist = 0;
 1150 
 1151 
 1152         if (td && !suser(td))
 1153                 privileged++;
 1154 
 1155 #ifdef SO_TIMESTAMP
 1156         if ((in6p->in6p_socket->so_options & SO_TIMESTAMP) != 0) {
 1157                 struct timeval tv;
 1158 
 1159                 microtime(&tv);
 1160                 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv),
 1161                                       SCM_TIMESTAMP, SOL_SOCKET);
 1162                 if (*mp) {
 1163                         mp = &(*mp)->m_next;
 1164                 }
 1165         }
 1166 #endif
 1167 
 1168         /* RFC 2292 sec. 5 */
 1169         if ((in6p->in6p_flags & IN6P_PKTINFO) != 0) {
 1170                 struct in6_pktinfo pi6;
 1171                 bcopy(&ip6->ip6_dst, &pi6.ipi6_addr, sizeof(struct in6_addr));
 1172                 if (IN6_IS_SCOPE_LINKLOCAL(&pi6.ipi6_addr))
 1173                         pi6.ipi6_addr.s6_addr16[1] = 0;
 1174                 pi6.ipi6_ifindex = (m && m->m_pkthdr.rcvif)
 1175                                         ? m->m_pkthdr.rcvif->if_index
 1176                                         : 0;
 1177                 *mp = sbcreatecontrol((caddr_t) &pi6,
 1178                         sizeof(struct in6_pktinfo), IPV6_PKTINFO,
 1179                         IPPROTO_IPV6);
 1180                 if (*mp)
 1181                         mp = &(*mp)->m_next;
 1182         }
 1183 
 1184         if ((in6p->in6p_flags & IN6P_HOPLIMIT) != 0) {
 1185                 int hlim = ip6->ip6_hlim & 0xff;
 1186                 *mp = sbcreatecontrol((caddr_t) &hlim,
 1187                         sizeof(int), IPV6_HOPLIMIT, IPPROTO_IPV6);
 1188                 if (*mp)
 1189                         mp = &(*mp)->m_next;
 1190         }
 1191 
 1192         /*
 1193          * IPV6_HOPOPTS socket option. We require super-user privilege
 1194          * for the option, but it might be too strict, since there might
 1195          * be some hop-by-hop options which can be returned to normal user.
 1196          * See RFC 2292 section 6.
 1197          */
 1198         if ((in6p->in6p_flags & IN6P_HOPOPTS) != 0 && privileged) {
 1199                 /*
 1200                  * Check if a hop-by-hop options header is contatined in the
 1201                  * received packet, and if so, store the options as ancillary
 1202                  * data. Note that a hop-by-hop options header must be
 1203                  * just after the IPv6 header, which fact is assured through
 1204                  * the IPv6 input processing.
 1205                  */
 1206                 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
 1207                 if (ip6->ip6_nxt == IPPROTO_HOPOPTS) {
 1208                         struct ip6_hbh *hbh;
 1209                         int hbhlen = 0;
 1210 #ifdef PULLDOWN_TEST
 1211                         struct mbuf *ext;
 1212 #endif
 1213 
 1214 #ifndef PULLDOWN_TEST
 1215                         hbh = (struct ip6_hbh *)(ip6 + 1);
 1216                         hbhlen = (hbh->ip6h_len + 1) << 3;
 1217 #else
 1218                         ext = ip6_pullexthdr(m, sizeof(struct ip6_hdr),
 1219                             ip6->ip6_nxt);
 1220                         if (ext == NULL) {
 1221                                 ip6stat.ip6s_tooshort++;
 1222                                 return;
 1223                         }
 1224                         hbh = mtod(ext, struct ip6_hbh *);
 1225                         hbhlen = (hbh->ip6h_len + 1) << 3;
 1226                         if (hbhlen != ext->m_len) {
 1227                                 m_freem(ext);
 1228                                 ip6stat.ip6s_tooshort++;
 1229                                 return;
 1230                         }
 1231 #endif
 1232 
 1233                         /*
 1234                          * XXX: We copy whole the header even if a jumbo
 1235                          * payload option is included, which option is to
 1236                          * be removed before returning in the RFC 2292.
 1237                          * Note: this constraint is removed in 2292bis.
 1238                          */
 1239                         *mp = sbcreatecontrol((caddr_t)hbh, hbhlen,
 1240                                               IPV6_HOPOPTS, IPPROTO_IPV6);
 1241                         if (*mp)
 1242                                 mp = &(*mp)->m_next;
 1243 #ifdef PULLDOWN_TEST
 1244                         m_freem(ext);
 1245 #endif
 1246                 }
 1247         }
 1248 
 1249         /* IPV6_DSTOPTS and IPV6_RTHDR socket options */
 1250         if ((in6p->in6p_flags & (IN6P_DSTOPTS | IN6P_RTHDRDSTOPTS)) != 0) {
 1251                 int proto, off, nxt;
 1252 
 1253                 /*
 1254                  * go through the header chain to see if a routing header is
 1255                  * contained in the packet. We need this information to store
 1256                  * destination options headers (if any) properly.
 1257                  * XXX: performance issue. We should record this info when
 1258                  * processing extension headers in incoming routine.
 1259                  * (todo) use m_aux? 
 1260                  */
 1261                 proto = IPPROTO_IPV6;
 1262                 off = 0;
 1263                 nxt = -1;
 1264                 while (1) {
 1265                         int newoff;
 1266 
 1267                         newoff = ip6_nexthdr(m, off, proto, &nxt);
 1268                         if (newoff < 0)
 1269                                 break;
 1270                         if (newoff < off) /* invalid, check for safety */
 1271                                 break;
 1272                         if ((proto = nxt) == IPPROTO_ROUTING) {
 1273                                 rthdr_exist = 1;
 1274                                 break;
 1275                         }
 1276                         off = newoff;
 1277                 }
 1278         }
 1279 
 1280         if ((in6p->in6p_flags &
 1281              (IN6P_RTHDR | IN6P_DSTOPTS | IN6P_RTHDRDSTOPTS)) != 0) {
 1282                 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
 1283                 int nxt = ip6->ip6_nxt, off = sizeof(struct ip6_hdr);
 1284 
 1285                 /*
 1286                  * Search for destination options headers or routing
 1287                  * header(s) through the header chain, and stores each
 1288                  * header as ancillary data.
 1289                  * Note that the order of the headers remains in
 1290                  * the chain of ancillary data.
 1291                  */
 1292                 while (1) {     /* is explicit loop prevention necessary? */
 1293                         struct ip6_ext *ip6e = NULL;
 1294                         int elen;
 1295 #ifdef PULLDOWN_TEST
 1296                         struct mbuf *ext = NULL;
 1297 #endif
 1298 
 1299                         /*
 1300                          * if it is not an extension header, don't try to
 1301                          * pull it from the chain.
 1302                          */
 1303                         switch (nxt) {
 1304                         case IPPROTO_DSTOPTS:
 1305                         case IPPROTO_ROUTING:
 1306                         case IPPROTO_HOPOPTS:
 1307                         case IPPROTO_AH: /* is it possible? */
 1308                                 break;
 1309                         default:
 1310                                 goto loopend;
 1311                         }
 1312 
 1313 #ifndef PULLDOWN_TEST
 1314                         if (off + sizeof(*ip6e) > m->m_len)
 1315                                 goto loopend;
 1316                         ip6e = (struct ip6_ext *)(mtod(m, caddr_t) + off);
 1317                         if (nxt == IPPROTO_AH)
 1318                                 elen = (ip6e->ip6e_len + 2) << 2;
 1319                         else
 1320                                 elen = (ip6e->ip6e_len + 1) << 3;
 1321                         if (off + elen > m->m_len)
 1322                                 goto loopend;
 1323 #else
 1324                         ext = ip6_pullexthdr(m, off, nxt);
 1325                         if (ext == NULL) {
 1326                                 ip6stat.ip6s_tooshort++;
 1327                                 return;
 1328                         }
 1329                         ip6e = mtod(ext, struct ip6_ext *);
 1330                         if (nxt == IPPROTO_AH)
 1331                                 elen = (ip6e->ip6e_len + 2) << 2;
 1332                         else
 1333                                 elen = (ip6e->ip6e_len + 1) << 3;
 1334                         if (elen != ext->m_len) {
 1335                                 m_freem(ext);
 1336                                 ip6stat.ip6s_tooshort++;
 1337                                 return;
 1338                         }
 1339 #endif
 1340 
 1341                         switch (nxt) {
 1342                         case IPPROTO_DSTOPTS:
 1343                                 if ((in6p->in6p_flags & IN6P_DSTOPTS) == 0)
 1344                                         break;
 1345 
 1346                                 /*
 1347                                  * We also require super-user privilege for
 1348                                  * the option.
 1349                                  * See the comments on IN6_HOPOPTS.
 1350                                  */
 1351                                 if (!privileged)
 1352                                         break;
 1353 
 1354                                 *mp = sbcreatecontrol((caddr_t)ip6e, elen,
 1355                                                       IPV6_DSTOPTS,
 1356                                                       IPPROTO_IPV6);
 1357                                 if (*mp)
 1358                                         mp = &(*mp)->m_next;
 1359                                 break;
 1360                         case IPPROTO_ROUTING:
 1361                                 if (!in6p->in6p_flags & IN6P_RTHDR)
 1362                                         break;
 1363 
 1364                                 *mp = sbcreatecontrol((caddr_t)ip6e, elen,
 1365                                                       IPV6_RTHDR,
 1366                                                       IPPROTO_IPV6);
 1367                                 if (*mp)
 1368                                         mp = &(*mp)->m_next;
 1369                                 break;
 1370                         case IPPROTO_HOPOPTS:
 1371                         case IPPROTO_AH: /* is it possible? */
 1372                                 break;
 1373 
 1374                         default:
 1375                                 /*
 1376                                  * other cases have been filtered in the above.
 1377                                  * none will visit this case.  here we supply
 1378                                  * the code just in case (nxt overwritten or
 1379                                  * other cases).
 1380                                  */
 1381 #ifdef PULLDOWN_TEST
 1382                                 m_freem(ext);
 1383 #endif
 1384                                 goto loopend;
 1385 
 1386                         }
 1387 
 1388                         /* proceed with the next header. */
 1389                         off += elen;
 1390                         nxt = ip6e->ip6e_nxt;
 1391                         ip6e = NULL;
 1392 #ifdef PULLDOWN_TEST
 1393                         m_freem(ext);
 1394                         ext = NULL;
 1395 #endif
 1396                 }
 1397           loopend:
 1398                 ;
 1399         }
 1400 
 1401 }
 1402 
 1403 #ifdef PULLDOWN_TEST
 1404 /*
 1405  * pull single extension header from mbuf chain.  returns single mbuf that
 1406  * contains the result, or NULL on error.
 1407  */
 1408 static struct mbuf *
 1409 ip6_pullexthdr(m, off, nxt)
 1410         struct mbuf *m;
 1411         size_t off;
 1412         int nxt;
 1413 {
 1414         struct ip6_ext ip6e;
 1415         size_t elen;
 1416         struct mbuf *n;
 1417 
 1418 #ifdef DIAGNOSTIC
 1419         switch (nxt) {
 1420         case IPPROTO_DSTOPTS:
 1421         case IPPROTO_ROUTING:
 1422         case IPPROTO_HOPOPTS:
 1423         case IPPROTO_AH: /* is it possible? */
 1424                 break;
 1425         default:
 1426                 printf("ip6_pullexthdr: invalid nxt=%d\n", nxt);
 1427         }
 1428 #endif
 1429 
 1430         m_copydata(m, off, sizeof(ip6e), (caddr_t)&ip6e);
 1431         if (nxt == IPPROTO_AH)
 1432                 elen = (ip6e.ip6e_len + 2) << 2;
 1433         else
 1434                 elen = (ip6e.ip6e_len + 1) << 3;
 1435 
 1436         MGET(n, M_DONTWAIT, MT_DATA);
 1437         if (n && elen >= MLEN) {
 1438                 MCLGET(n, M_DONTWAIT);
 1439                 if ((n->m_flags & M_EXT) == 0) {
 1440                         m_free(n);
 1441                         n = NULL;
 1442                 }
 1443         }
 1444         if (!n)
 1445                 return NULL;
 1446 
 1447         n->m_len = 0;
 1448         if (elen >= M_TRAILINGSPACE(n)) {
 1449                 m_free(n);
 1450                 return NULL;
 1451         }
 1452 
 1453         m_copydata(m, off, elen, mtod(n, caddr_t));
 1454         n->m_len = elen;
 1455         return n;
 1456 }
 1457 #endif
 1458 
 1459 /*
 1460  * Get pointer to the previous header followed by the header
 1461  * currently processed.
 1462  * XXX: This function supposes that
 1463  *      M includes all headers,
 1464  *      the next header field and the header length field of each header
 1465  *      are valid, and
 1466  *      the sum of each header length equals to OFF.
 1467  * Because of these assumptions, this function must be called very
 1468  * carefully. Moreover, it will not be used in the near future when
 1469  * we develop `neater' mechanism to process extension headers.
 1470  */
 1471 char *
 1472 ip6_get_prevhdr(m, off)
 1473         struct mbuf *m;
 1474         int off;
 1475 {
 1476         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
 1477 
 1478         if (off == sizeof(struct ip6_hdr))
 1479                 return(&ip6->ip6_nxt);
 1480         else {
 1481                 int len, nxt;
 1482                 struct ip6_ext *ip6e = NULL;
 1483 
 1484                 nxt = ip6->ip6_nxt;
 1485                 len = sizeof(struct ip6_hdr);
 1486                 while (len < off) {
 1487                         ip6e = (struct ip6_ext *)(mtod(m, caddr_t) + len);
 1488 
 1489                         switch (nxt) {
 1490                         case IPPROTO_FRAGMENT:
 1491                                 len += sizeof(struct ip6_frag);
 1492                                 break;
 1493                         case IPPROTO_AH:
 1494                                 len += (ip6e->ip6e_len + 2) << 2;
 1495                                 break;
 1496                         default:
 1497                                 len += (ip6e->ip6e_len + 1) << 3;
 1498                                 break;
 1499                         }
 1500                         nxt = ip6e->ip6e_nxt;
 1501                 }
 1502                 if (ip6e)
 1503                         return(&ip6e->ip6e_nxt);
 1504                 else
 1505                         return NULL;
 1506         }
 1507 }
 1508 
 1509 /*
 1510  * get next header offset.  m will be retained.
 1511  */
 1512 int
 1513 ip6_nexthdr(m, off, proto, nxtp)
 1514         struct mbuf *m;
 1515         int off;
 1516         int proto;
 1517         int *nxtp;
 1518 {
 1519         struct ip6_hdr ip6;
 1520         struct ip6_ext ip6e;
 1521         struct ip6_frag fh;
 1522 
 1523         /* just in case */
 1524         if (m == NULL)
 1525                 panic("ip6_nexthdr: m == NULL");
 1526         if ((m->m_flags & M_PKTHDR) == 0 || m->m_pkthdr.len < off)
 1527                 return -1;
 1528 
 1529         switch (proto) {
 1530         case IPPROTO_IPV6:
 1531                 if (m->m_pkthdr.len < off + sizeof(ip6))
 1532                         return -1;
 1533                 m_copydata(m, off, sizeof(ip6), (caddr_t)&ip6);
 1534                 if (nxtp)
 1535                         *nxtp = ip6.ip6_nxt;
 1536                 off += sizeof(ip6);
 1537                 return off;
 1538 
 1539         case IPPROTO_FRAGMENT:
 1540                 /*
 1541                  * terminate parsing if it is not the first fragment,
 1542                  * it does not make sense to parse through it.
 1543                  */
 1544                 if (m->m_pkthdr.len < off + sizeof(fh))
 1545                         return -1;
 1546                 m_copydata(m, off, sizeof(fh), (caddr_t)&fh);
 1547                 if ((ntohs(fh.ip6f_offlg) & IP6F_OFF_MASK) != 0)
 1548                         return -1;
 1549                 if (nxtp)
 1550                         *nxtp = fh.ip6f_nxt;
 1551                 off += sizeof(struct ip6_frag);
 1552                 return off;
 1553 
 1554         case IPPROTO_AH:
 1555                 if (m->m_pkthdr.len < off + sizeof(ip6e))
 1556                         return -1;
 1557                 m_copydata(m, off, sizeof(ip6e), (caddr_t)&ip6e);
 1558                 if (nxtp)
 1559                         *nxtp = ip6e.ip6e_nxt;
 1560                 off += (ip6e.ip6e_len + 2) << 2;
 1561                 return off;
 1562 
 1563         case IPPROTO_HOPOPTS:
 1564         case IPPROTO_ROUTING:
 1565         case IPPROTO_DSTOPTS:
 1566                 if (m->m_pkthdr.len < off + sizeof(ip6e))
 1567                         return -1;
 1568                 m_copydata(m, off, sizeof(ip6e), (caddr_t)&ip6e);
 1569                 if (nxtp)
 1570                         *nxtp = ip6e.ip6e_nxt;
 1571                 off += (ip6e.ip6e_len + 1) << 3;
 1572                 return off;
 1573 
 1574         case IPPROTO_NONE:
 1575         case IPPROTO_ESP:
 1576         case IPPROTO_IPCOMP:
 1577                 /* give up */
 1578                 return -1;
 1579 
 1580         default:
 1581                 return -1;
 1582         }
 1583 
 1584         return -1;
 1585 }
 1586 
 1587 /*
 1588  * get offset for the last header in the chain.  m will be kept untainted.
 1589  */
 1590 int
 1591 ip6_lasthdr(m, off, proto, nxtp)
 1592         struct mbuf *m;
 1593         int off;
 1594         int proto;
 1595         int *nxtp;
 1596 {
 1597         int newoff;
 1598         int nxt;
 1599 
 1600         if (!nxtp) {
 1601                 nxt = -1;
 1602                 nxtp = &nxt;
 1603         }
 1604         while (1) {
 1605                 newoff = ip6_nexthdr(m, off, proto, nxtp);
 1606                 if (newoff < 0)
 1607                         return off;
 1608                 else if (newoff < off)
 1609                         return -1;      /* invalid */
 1610                 else if (newoff == off)
 1611                         return newoff;
 1612 
 1613                 off = newoff;
 1614                 proto = *nxtp;
 1615         }
 1616 }
 1617 
 1618 struct ip6aux *
 1619 ip6_addaux(m)
 1620         struct mbuf *m;
 1621 {
 1622         struct m_tag *tag = m_tag_find(m, PACKET_TAG_IPV6_INPUT, NULL);
 1623         if (!tag) {
 1624                 tag = m_tag_get(PACKET_TAG_IPV6_INPUT,
 1625                                 sizeof (struct ip6aux),
 1626                                 M_NOWAIT);
 1627                 if (tag)
 1628                         m_tag_prepend(m, tag);
 1629         }
 1630         if (tag)
 1631                 bzero(tag+1, sizeof (struct ip6aux));
 1632         return tag ? (struct ip6aux*)(tag+1) : NULL;
 1633 }
 1634 
 1635 struct ip6aux *
 1636 ip6_findaux(m)
 1637         struct mbuf *m;
 1638 {
 1639         struct m_tag *tag = m_tag_find(m, PACKET_TAG_IPV6_INPUT, NULL);
 1640         return tag ? (struct ip6aux*)(tag+1) : NULL;
 1641 }
 1642 
 1643 void
 1644 ip6_delaux(m)
 1645         struct mbuf *m;
 1646 {
 1647         struct m_tag *tag = m_tag_find(m, PACKET_TAG_IPV6_INPUT, NULL);
 1648         if (tag)
 1649                 m_tag_delete(m, tag);
 1650 }
 1651 
 1652 /*
 1653  * System control for IP6
 1654  */
 1655 
 1656 u_char  inet6ctlerrmap[PRC_NCMDS] = {
 1657         0,              0,              0,              0,
 1658         0,              EMSGSIZE,       EHOSTDOWN,      EHOSTUNREACH,
 1659         EHOSTUNREACH,   EHOSTUNREACH,   ECONNREFUSED,   ECONNREFUSED,
 1660         EMSGSIZE,       EHOSTUNREACH,   0,              0,
 1661         0,              0,              0,              0,
 1662         ENOPROTOOPT
 1663 };

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