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: stable/4/sys/netinet6/ip6_input.c 130180 2004-06-07 08:54:23Z ume $   */
    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 
   73 #include <sys/param.h>
   74 #include <sys/systm.h>
   75 #include <sys/malloc.h>
   76 #include <sys/mbuf.h>
   77 #include <sys/domain.h>
   78 #include <sys/protosw.h>
   79 #include <sys/socket.h>
   80 #include <sys/socketvar.h>
   81 #include <sys/errno.h>
   82 #include <sys/time.h>
   83 #include <sys/kernel.h>
   84 #include <sys/syslog.h>
   85 #include <sys/proc.h>
   86 
   87 #include <net/if.h>
   88 #include <net/if_types.h>
   89 #include <net/if_dl.h>
   90 #include <net/route.h>
   91 #include <net/netisr.h>
   92 #include <net/intrq.h>
   93 
   94 #include <netinet/in.h>
   95 #include <netinet/in_systm.h>
   96 #ifdef INET
   97 #include <netinet/ip.h>
   98 #include <netinet/ip_icmp.h>
   99 #endif /* INET */
  100 #include <netinet/ip6.h>
  101 #include <netinet6/in6_var.h>
  102 #include <netinet6/ip6_var.h>
  103 #include <netinet/in_pcb.h>
  104 #include <netinet/icmp6.h>
  105 #include <netinet6/in6_ifattach.h>
  106 #include <netinet6/nd6.h>
  107 #include <netinet6/in6_prefix.h>
  108 
  109 #ifdef IPSEC
  110 #include <netinet6/ipsec.h>
  111 #ifdef INET6
  112 #include <netinet6/ipsec6.h>
  113 #endif
  114 #endif
  115 
  116 #ifdef FAST_IPSEC
  117 #include <netipsec/ipsec.h>
  118 #include <netipsec/ipsec6.h>
  119 #define IPSEC
  120 #endif /* FAST_IPSEC */
  121 
  122 #include <netinet6/ip6_fw.h>
  123 
  124 #include <netinet6/ip6protosw.h>
  125 
  126 /* we need it for NLOOP. */
  127 #include "loop.h"
  128 
  129 #include <net/net_osdep.h>
  130 
  131 extern int (*fr_checkp) __P((struct ip *, int, struct ifnet *, int, struct mbuf **));
  132 
  133 extern struct domain inet6domain;
  134 extern struct ip6protosw inet6sw[];
  135 
  136 u_char ip6_protox[IPPROTO_MAX];
  137 static int ip6qmaxlen = IFQ_MAXLEN;
  138 struct in6_ifaddr *in6_ifaddr;
  139 
  140 extern struct callout in6_tmpaddrtimer_ch;
  141 
  142 int ip6_forward_srcrt;                  /* XXX */
  143 int ip6_sourcecheck;                    /* XXX */
  144 int ip6_sourcecheck_interval;           /* XXX */
  145 const int int6intrq_present = 1;
  146 
  147 int ip6_ours_check_algorithm;
  148 
  149 
  150 /* firewall hooks */
  151 ip6_fw_chk_t *ip6_fw_chk_ptr;
  152 ip6_fw_ctl_t *ip6_fw_ctl_ptr;
  153 int ip6_fw_enable = 1;
  154 
  155 struct ip6stat ip6stat;
  156 
  157 static void ip6_init2 __P((void *));
  158 static struct ip6aux *ip6_setdstifaddr __P((struct mbuf *, struct in6_ifaddr *));
  159 static int ip6_hopopts_input __P((u_int32_t *, u_int32_t *, struct mbuf **, int *));
  160 #ifdef PULLDOWN_TEST
  161 static struct mbuf *ip6_pullexthdr __P((struct mbuf *, size_t, int));
  162 #endif
  163 
  164 
  165 /*
  166  * IP6 initialization: fill in IP6 protocol switch table.
  167  * All protocols not implemented in kernel go to raw IP6 protocol handler.
  168  */
  169 void
  170 ip6_init()
  171 {
  172         struct ip6protosw *pr;
  173         int i;
  174         struct timeval tv;
  175 
  176 #ifdef DIAGNOSTIC
  177         if (sizeof(struct protosw) != sizeof(struct ip6protosw))
  178                 panic("sizeof(protosw) != sizeof(ip6protosw)");
  179 #endif
  180         pr = (struct ip6protosw *)pffindproto(PF_INET6, IPPROTO_RAW, SOCK_RAW);
  181         if (pr == 0)
  182                 panic("ip6_init");
  183         for (i = 0; i < IPPROTO_MAX; i++)
  184                 ip6_protox[i] = pr - inet6sw;
  185         for (pr = (struct ip6protosw *)inet6domain.dom_protosw;
  186             pr < (struct ip6protosw *)inet6domain.dom_protoswNPROTOSW; pr++)
  187                 if (pr->pr_domain->dom_family == PF_INET6 &&
  188                     pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW)
  189                         ip6_protox[pr->pr_protocol] = pr - inet6sw;
  190         ip6intrq.ifq_maxlen = ip6qmaxlen;
  191         register_netisr(NETISR_IPV6, ip6intr);
  192         nd6_init();
  193         frag6_init();
  194         /*
  195          * in many cases, random() here does NOT return random number
  196          * as initialization during bootstrap time occur in fixed order.
  197          */
  198         microtime(&tv);
  199         ip6_flow_seq = random() ^ tv.tv_usec;
  200         microtime(&tv);
  201         ip6_desync_factor = (random() ^ tv.tv_usec) % MAX_TEMP_DESYNC_FACTOR;
  202 }
  203 
  204 static void
  205 ip6_init2(dummy)
  206         void *dummy;
  207 {
  208 
  209         /*
  210          * to route local address of p2p link to loopback,
  211          * assign loopback address first.
  212          */
  213         in6_ifattach(&loif[0], NULL);
  214 
  215         /* nd6_timer_init */
  216         callout_init(&nd6_timer_ch);
  217         callout_reset(&nd6_timer_ch, hz, nd6_timer, NULL);
  218 
  219         /* router renumbering prefix list maintenance */
  220         callout_init(&in6_rr_timer_ch);
  221         callout_reset(&in6_rr_timer_ch, hz, in6_rr_timer, NULL);
  222 
  223         /* timer for regeneranation of temporary addresses randomize ID */
  224         callout_reset(&in6_tmpaddrtimer_ch,
  225                       (ip6_temp_preferred_lifetime - ip6_desync_factor -
  226                        ip6_temp_regen_advance) * hz,
  227                       in6_tmpaddrtimer, NULL);
  228 }
  229 
  230 /* cheat */
  231 /* This must be after route_init(), which is now SI_ORDER_THIRD */
  232 SYSINIT(netinet6init2, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, ip6_init2, NULL);
  233 
  234 /*
  235  * IP6 input interrupt handling. Just pass the packet to ip6_input.
  236  */
  237 void
  238 ip6intr()
  239 {
  240         int s;
  241         struct mbuf *m;
  242 
  243         for (;;) {
  244                 s = splimp();
  245                 IF_DEQUEUE(&ip6intrq, m);
  246                 splx(s);
  247                 if (m == 0)
  248                         return;
  249                 ip6_input(m);
  250         }
  251 }
  252 
  253 extern struct   route_in6 ip6_forward_rt;
  254 
  255 void
  256 ip6_input(m)
  257         struct mbuf *m;
  258 {
  259         struct ip6_hdr *ip6;
  260         int off = sizeof(struct ip6_hdr), nest;
  261         u_int32_t plen;
  262         u_int32_t rtalert = ~0;
  263         int nxt, ours = 0;
  264         struct ifnet *deliverifp = NULL;
  265 
  266 #ifdef IPSEC
  267         /*
  268          * should the inner packet be considered authentic?
  269          * see comment in ah4_input().
  270          */
  271         if (m) {
  272                 m->m_flags &= ~M_AUTHIPHDR;
  273                 m->m_flags &= ~M_AUTHIPDGM;
  274         }
  275 #endif
  276 
  277         /*
  278          * make sure we don't have onion peering information into m_aux.
  279          */
  280         ip6_delaux(m);
  281 
  282         /*
  283          * mbuf statistics
  284          */
  285         if (m->m_flags & M_EXT) {
  286                 if (m->m_next)
  287                         ip6stat.ip6s_mext2m++;
  288                 else
  289                         ip6stat.ip6s_mext1++;
  290         } else {
  291 #define M2MMAX  (sizeof(ip6stat.ip6s_m2m)/sizeof(ip6stat.ip6s_m2m[0]))
  292                 if (m->m_next) {
  293                         if (m->m_flags & M_LOOP) {
  294                                 ip6stat.ip6s_m2m[loif[0].if_index]++;   /* XXX */
  295                         } else if (m->m_pkthdr.rcvif->if_index < M2MMAX)
  296                                 ip6stat.ip6s_m2m[m->m_pkthdr.rcvif->if_index]++;
  297                         else
  298                                 ip6stat.ip6s_m2m[0]++;
  299                 } else
  300                         ip6stat.ip6s_m1++;
  301 #undef M2MMAX
  302         }
  303 
  304         in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_receive);
  305         ip6stat.ip6s_total++;
  306 
  307 #ifndef PULLDOWN_TEST
  308         /*
  309          * L2 bridge code and some other code can return mbuf chain
  310          * that does not conform to KAME requirement.  too bad.
  311          * XXX: fails to join if interface MTU > MCLBYTES.  jumbogram?
  312          */
  313         if (m && m->m_next != NULL && m->m_pkthdr.len < MCLBYTES) {
  314                 struct mbuf *n;
  315 
  316                 MGETHDR(n, M_DONTWAIT, MT_HEADER);
  317                 if (n)
  318                         M_MOVE_PKTHDR(n, m);
  319                 if (n && n->m_pkthdr.len > MHLEN) {
  320                         MCLGET(n, M_DONTWAIT);
  321                         if ((n->m_flags & M_EXT) == 0) {
  322                                 m_freem(n);
  323                                 n = NULL;
  324                         }
  325                 }
  326                 if (n == NULL) {
  327                         m_freem(m);
  328                         return; /*ENOBUFS*/
  329                 }
  330 
  331                 m_copydata(m, 0, n->m_pkthdr.len, mtod(n, caddr_t));
  332                 n->m_len = n->m_pkthdr.len;
  333                 m_freem(m);
  334                 m = n;
  335         }
  336         IP6_EXTHDR_CHECK(m, 0, sizeof(struct ip6_hdr), /*nothing*/);
  337 #endif
  338 
  339         if (m->m_len < sizeof(struct ip6_hdr)) {
  340                 struct ifnet *inifp;
  341                 inifp = m->m_pkthdr.rcvif;
  342                 if ((m = m_pullup(m, sizeof(struct ip6_hdr))) == 0) {
  343                         ip6stat.ip6s_toosmall++;
  344                         in6_ifstat_inc(inifp, ifs6_in_hdrerr);
  345                         return;
  346                 }
  347         }
  348 
  349         ip6 = mtod(m, struct ip6_hdr *);
  350 
  351         if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) {
  352                 ip6stat.ip6s_badvers++;
  353                 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_hdrerr);
  354                 goto bad;
  355         }
  356 
  357         /*
  358          * Check if we want to allow this packet to be processed.
  359          * Consider it to be bad if not.
  360          */
  361         if (fr_checkp) {
  362                 struct  mbuf    *m1 = m;
  363 
  364                 if ((*fr_checkp)((struct ip *)ip6, sizeof(*ip6),
  365                                  m->m_pkthdr.rcvif, 0, &m1) != 0)
  366                         return;
  367                 m = m1;
  368                 if (m == NULL)
  369                         return;
  370                 ip6 = mtod(m, struct ip6_hdr *);
  371         }
  372 
  373         ip6stat.ip6s_nxthist[ip6->ip6_nxt]++;
  374 
  375         /*
  376          * Check with the firewall...
  377          */
  378         if (ip6_fw_enable && ip6_fw_chk_ptr) {
  379                 u_short port = 0;
  380                 /* If ipfw says divert, we have to just drop packet */
  381                 /* use port as a dummy argument */
  382                 if ((*ip6_fw_chk_ptr)(&ip6, NULL, &port, &m)) {
  383                         m_freem(m);
  384                         m = NULL;
  385                 }
  386                 if (!m)
  387                         return;
  388         }
  389 
  390         /*
  391          * Check against address spoofing/corruption.
  392          */
  393         if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_src) ||
  394             IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_dst)) {
  395                 /*
  396                  * XXX: "badscope" is not very suitable for a multicast source.
  397                  */
  398                 ip6stat.ip6s_badscope++;
  399                 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
  400                 goto bad;
  401         }
  402         if ((IN6_IS_ADDR_LOOPBACK(&ip6->ip6_src) ||
  403              IN6_IS_ADDR_LOOPBACK(&ip6->ip6_dst)) &&
  404             (m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) {
  405                 ip6stat.ip6s_badscope++;
  406                 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
  407                 goto bad;
  408         }
  409 
  410         /*
  411          * The following check is not documented in specs.  A malicious
  412          * party may be able to use IPv4 mapped addr to confuse tcp/udp stack
  413          * and bypass security checks (act as if it was from 127.0.0.1 by using
  414          * IPv6 src ::ffff:127.0.0.1).  Be cautious.
  415          *
  416          * This check chokes if we are in an SIIT cloud.  As none of BSDs
  417          * support IPv4-less kernel compilation, we cannot support SIIT
  418          * environment at all.  So, it makes more sense for us to reject any
  419          * malicious packets for non-SIIT environment, than try to do a
  420          * partical support for SIIT environment.
  421          */
  422         if (IN6_IS_ADDR_V4MAPPED(&ip6->ip6_src) ||
  423             IN6_IS_ADDR_V4MAPPED(&ip6->ip6_dst)) {
  424                 ip6stat.ip6s_badscope++;
  425                 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
  426                 goto bad;
  427         }
  428 #if 0
  429         /*
  430          * Reject packets with IPv4 compatible addresses (auto tunnel).
  431          *
  432          * The code forbids auto tunnel relay case in RFC1933 (the check is
  433          * stronger than RFC1933).  We may want to re-enable it if mech-xx
  434          * is revised to forbid relaying case.
  435          */
  436         if (IN6_IS_ADDR_V4COMPAT(&ip6->ip6_src) ||
  437             IN6_IS_ADDR_V4COMPAT(&ip6->ip6_dst)) {
  438                 ip6stat.ip6s_badscope++;
  439                 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
  440                 goto bad;
  441         }
  442 #endif
  443 
  444         /* drop packets if interface ID portion is already filled */
  445         if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) {
  446                 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src) &&
  447                     ip6->ip6_src.s6_addr16[1]) {
  448                         ip6stat.ip6s_badscope++;
  449                         goto bad;
  450                 }
  451                 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst) &&
  452                     ip6->ip6_dst.s6_addr16[1]) {
  453                         ip6stat.ip6s_badscope++;
  454                         goto bad;
  455                 }
  456         }
  457 
  458         if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src))
  459                 ip6->ip6_src.s6_addr16[1]
  460                         = htons(m->m_pkthdr.rcvif->if_index);
  461         if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst))
  462                 ip6->ip6_dst.s6_addr16[1]
  463                         = htons(m->m_pkthdr.rcvif->if_index);
  464 
  465 #if 0 /* this case seems to be unnecessary. (jinmei, 20010401) */
  466         /*
  467          * We use rt->rt_ifp to determine if the address is ours or not.
  468          * If rt_ifp is lo0, the address is ours.
  469          * The problem here is, rt->rt_ifp for fe80::%lo0/64 is set to lo0,
  470          * so any address under fe80::%lo0/64 will be mistakenly considered
  471          * local.  The special case is supplied to handle the case properly
  472          * by actually looking at interface addresses
  473          * (using in6ifa_ifpwithaddr).
  474          */
  475         if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) != 0 &&
  476             IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_dst)) {
  477                 if (!in6ifa_ifpwithaddr(m->m_pkthdr.rcvif, &ip6->ip6_dst)) {
  478                         icmp6_error(m, ICMP6_DST_UNREACH,
  479                             ICMP6_DST_UNREACH_ADDR, 0);
  480                         /* m is already freed */
  481                         return;
  482                 }
  483 
  484                 ours = 1;
  485                 deliverifp = m->m_pkthdr.rcvif;
  486                 goto hbhcheck;
  487         }
  488 #endif
  489 
  490         /*
  491          * Multicast check
  492          */
  493         if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
  494                 struct  in6_multi *in6m = 0;
  495 
  496                 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_mcast);
  497                 /*
  498                  * See if we belong to the destination multicast group on the
  499                  * arrival interface.
  500                  */
  501                 IN6_LOOKUP_MULTI(ip6->ip6_dst, m->m_pkthdr.rcvif, in6m);
  502                 if (in6m)
  503                         ours = 1;
  504                 else if (!ip6_mrouter) {
  505                         ip6stat.ip6s_notmember++;
  506                         ip6stat.ip6s_cantforward++;
  507                         in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
  508                         goto bad;
  509                 }
  510                 deliverifp = m->m_pkthdr.rcvif;
  511                 goto hbhcheck;
  512         }
  513 
  514         /*
  515          *  Unicast check
  516          */
  517         switch (ip6_ours_check_algorithm) {
  518         default:
  519                 /*
  520                  * XXX: I intentionally broke our indentation rule here,
  521                  *      since this switch-case is just for measurement and
  522                  *      therefore should soon be removed.
  523                  */
  524         if (ip6_forward_rt.ro_rt != NULL &&
  525             (ip6_forward_rt.ro_rt->rt_flags & RTF_UP) != 0 && 
  526             IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst,
  527                                &((struct sockaddr_in6 *)(&ip6_forward_rt.ro_dst))->sin6_addr))
  528                 ip6stat.ip6s_forward_cachehit++;
  529         else {
  530                 struct sockaddr_in6 *dst6;
  531 
  532                 if (ip6_forward_rt.ro_rt) {
  533                         /* route is down or destination is different */
  534                         ip6stat.ip6s_forward_cachemiss++;
  535                         RTFREE(ip6_forward_rt.ro_rt);
  536                         ip6_forward_rt.ro_rt = 0;
  537                 }
  538 
  539                 bzero(&ip6_forward_rt.ro_dst, sizeof(struct sockaddr_in6));
  540                 dst6 = (struct sockaddr_in6 *)&ip6_forward_rt.ro_dst;
  541                 dst6->sin6_len = sizeof(struct sockaddr_in6);
  542                 dst6->sin6_family = AF_INET6;
  543                 dst6->sin6_addr = ip6->ip6_dst;
  544 #ifdef SCOPEDROUTING
  545                 ip6_forward_rt.ro_dst.sin6_scope_id =
  546                         in6_addr2scopeid(m->m_pkthdr.rcvif, &ip6->ip6_dst);
  547 #endif
  548 
  549                 rtalloc_ign((struct route *)&ip6_forward_rt, RTF_PRCLONING);
  550         }
  551 
  552 #define rt6_key(r) ((struct sockaddr_in6 *)((r)->rt_nodes->rn_key))
  553 
  554         /*
  555          * Accept the packet if the forwarding interface to the destination
  556          * according to the routing table is the loopback interface,
  557          * unless the associated route has a gateway.
  558          * Note that this approach causes to accept a packet if there is a
  559          * route to the loopback interface for the destination of the packet.
  560          * But we think it's even useful in some situations, e.g. when using
  561          * a special daemon which wants to intercept the packet.
  562          *
  563          * XXX: some OSes automatically make a cloned route for the destination
  564          * of an outgoing packet.  If the outgoing interface of the packet
  565          * is a loopback one, the kernel would consider the packet to be
  566          * accepted, even if we have no such address assinged on the interface.
  567          * We check the cloned flag of the route entry to reject such cases,
  568          * assuming that route entries for our own addresses are not made by
  569          * cloning (it should be true because in6_addloop explicitly installs
  570          * the host route).  However, we might have to do an explicit check
  571          * while it would be less efficient.  Or, should we rather install a
  572          * reject route for such a case?
  573          */
  574         if (ip6_forward_rt.ro_rt &&
  575             (ip6_forward_rt.ro_rt->rt_flags &
  576              (RTF_HOST|RTF_GATEWAY)) == RTF_HOST &&
  577 #ifdef RTF_WASCLONED
  578             !(ip6_forward_rt.ro_rt->rt_flags & RTF_WASCLONED) &&
  579 #endif
  580 #ifdef RTF_CLONED
  581             !(ip6_forward_rt.ro_rt->rt_flags & RTF_CLONED) &&
  582 #endif
  583 #if 0
  584             /*
  585              * The check below is redundant since the comparison of
  586              * the destination and the key of the rtentry has
  587              * already done through looking up the routing table.
  588              */
  589             IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst,
  590                                 &rt6_key(ip6_forward_rt.ro_rt)->sin6_addr)
  591 #endif
  592             ip6_forward_rt.ro_rt->rt_ifp->if_type == IFT_LOOP) {
  593                 struct in6_ifaddr *ia6 =
  594                         (struct in6_ifaddr *)ip6_forward_rt.ro_rt->rt_ifa;
  595 
  596                 /*
  597                  * record address information into m_aux.
  598                  */
  599                 (void)ip6_setdstifaddr(m, ia6);
  600 
  601                 /*
  602                  * packets to a tentative, duplicated, or somehow invalid
  603                  * address must not be accepted.
  604                  */
  605                 if (!(ia6->ia6_flags & IN6_IFF_NOTREADY)) {
  606                         /* this address is ready */
  607                         ours = 1;
  608                         deliverifp = ia6->ia_ifp;       /* correct? */
  609                         /* Count the packet in the ip address stats */
  610                         ia6->ia_ifa.if_ipackets++;
  611                         ia6->ia_ifa.if_ibytes += m->m_pkthdr.len;
  612                         goto hbhcheck;
  613                 } else {
  614                         /* address is not ready, so discard the packet. */
  615                         nd6log((LOG_INFO,
  616                             "ip6_input: packet to an unready address %s->%s\n",
  617                             ip6_sprintf(&ip6->ip6_src),
  618                             ip6_sprintf(&ip6->ip6_dst)));
  619 
  620                         goto bad;
  621                 }
  622         }
  623         } /* XXX indentation (see above) */
  624 
  625         /*
  626          * FAITH(Firewall Aided Internet Translator)
  627          */
  628         if (ip6_keepfaith) {
  629                 if (ip6_forward_rt.ro_rt && ip6_forward_rt.ro_rt->rt_ifp
  630                  && ip6_forward_rt.ro_rt->rt_ifp->if_type == IFT_FAITH) {
  631                         /* XXX do we need more sanity checks? */
  632                         ours = 1;
  633                         deliverifp = ip6_forward_rt.ro_rt->rt_ifp; /* faith */
  634                         goto hbhcheck;
  635                 }
  636         }
  637 
  638         /*
  639          * Now there is no reason to process the packet if it's not our own
  640          * and we're not a router.
  641          */
  642         if (!ip6_forwarding) {
  643                 ip6stat.ip6s_cantforward++;
  644                 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
  645                 goto bad;
  646         }
  647 
  648   hbhcheck:
  649         /*
  650          * record address information into m_aux, if we don't have one yet.
  651          * note that we are unable to record it, if the address is not listed
  652          * as our interface address (e.g. multicast addresses, addresses
  653          * within FAITH prefixes and such).
  654          */
  655         if (deliverifp && !ip6_getdstifaddr(m)) {
  656                 struct in6_ifaddr *ia6;
  657 
  658                 ia6 = in6_ifawithifp(deliverifp, &ip6->ip6_dst);
  659                 if (ia6) {
  660                         if (!ip6_setdstifaddr(m, ia6)) {
  661                                 /*
  662                                  * XXX maybe we should drop the packet here,
  663                                  * as we could not provide enough information
  664                                  * to the upper layers.
  665                                  */
  666                         }
  667                 }
  668         }
  669 
  670         /*
  671          * Process Hop-by-Hop options header if it's contained.
  672          * m may be modified in ip6_hopopts_input().
  673          * If a JumboPayload option is included, plen will also be modified.
  674          */
  675         plen = (u_int32_t)ntohs(ip6->ip6_plen);
  676         if (ip6->ip6_nxt == IPPROTO_HOPOPTS) {
  677                 struct ip6_hbh *hbh;
  678 
  679                 if (ip6_hopopts_input(&plen, &rtalert, &m, &off)) {
  680 #if 0   /*touches NULL pointer*/
  681                         in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
  682 #endif
  683                         return; /* m have already been freed */
  684                 }
  685 
  686                 /* adjust pointer */
  687                 ip6 = mtod(m, struct ip6_hdr *);
  688 
  689                 /*
  690                  * if the payload length field is 0 and the next header field
  691                  * indicates Hop-by-Hop Options header, then a Jumbo Payload
  692                  * option MUST be included.
  693                  */
  694                 if (ip6->ip6_plen == 0 && plen == 0) {
  695                         /*
  696                          * Note that if a valid jumbo payload option is
  697                          * contained, ip6_hoptops_input() must set a valid
  698                          * (non-zero) payload length to the variable plen. 
  699                          */
  700                         ip6stat.ip6s_badoptions++;
  701                         in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
  702                         in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_hdrerr);
  703                         icmp6_error(m, ICMP6_PARAM_PROB,
  704                                     ICMP6_PARAMPROB_HEADER,
  705                                     (caddr_t)&ip6->ip6_plen - (caddr_t)ip6);
  706                         return;
  707                 }
  708 #ifndef PULLDOWN_TEST
  709                 /* ip6_hopopts_input() ensures that mbuf is contiguous */
  710                 hbh = (struct ip6_hbh *)(ip6 + 1);
  711 #else
  712                 IP6_EXTHDR_GET(hbh, struct ip6_hbh *, m, sizeof(struct ip6_hdr),
  713                         sizeof(struct ip6_hbh));
  714                 if (hbh == NULL) {
  715                         ip6stat.ip6s_tooshort++;
  716                         return;
  717                 }
  718 #endif
  719                 nxt = hbh->ip6h_nxt;
  720 
  721                 /*
  722                  * accept the packet if a router alert option is included
  723                  * and we act as an IPv6 router.
  724                  */
  725                 if (rtalert != ~0 && ip6_forwarding)
  726                         ours = 1;
  727         } else
  728                 nxt = ip6->ip6_nxt;
  729 
  730         /*
  731          * Check that the amount of data in the buffers
  732          * is as at least much as the IPv6 header would have us expect.
  733          * Trim mbufs if longer than we expect.
  734          * Drop packet if shorter than we expect.
  735          */
  736         if (m->m_pkthdr.len - sizeof(struct ip6_hdr) < plen) {
  737                 ip6stat.ip6s_tooshort++;
  738                 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_truncated);
  739                 goto bad;
  740         }
  741         if (m->m_pkthdr.len > sizeof(struct ip6_hdr) + plen) {
  742                 if (m->m_len == m->m_pkthdr.len) {
  743                         m->m_len = sizeof(struct ip6_hdr) + plen;
  744                         m->m_pkthdr.len = sizeof(struct ip6_hdr) + plen;
  745                 } else
  746                         m_adj(m, sizeof(struct ip6_hdr) + plen - m->m_pkthdr.len);
  747         }
  748 
  749         /*
  750          * Forward if desirable.
  751          */
  752         if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
  753                 /*
  754                  * If we are acting as a multicast router, all
  755                  * incoming multicast packets are passed to the
  756                  * kernel-level multicast forwarding function.
  757                  * The packet is returned (relatively) intact; if
  758                  * ip6_mforward() returns a non-zero value, the packet
  759                  * must be discarded, else it may be accepted below.
  760                  */
  761                 if (ip6_mrouter && ip6_mforward(ip6, m->m_pkthdr.rcvif, m)) {
  762                         ip6stat.ip6s_cantforward++;
  763                         m_freem(m);
  764                         return;
  765                 }
  766                 if (!ours) {
  767                         m_freem(m);
  768                         return;
  769                 }
  770         } else if (!ours) {
  771                 ip6_forward(m, 0);
  772                 return;
  773         }       
  774 
  775         ip6 = mtod(m, struct ip6_hdr *);
  776 
  777         /*
  778          * Malicious party may be able to use IPv4 mapped addr to confuse
  779          * tcp/udp stack and bypass security checks (act as if it was from
  780          * 127.0.0.1 by using IPv6 src ::ffff:127.0.0.1).  Be cautious.
  781          *
  782          * For SIIT end node behavior, you may want to disable the check.
  783          * However, you will  become vulnerable to attacks using IPv4 mapped
  784          * source.
  785          */
  786         if (IN6_IS_ADDR_V4MAPPED(&ip6->ip6_src) ||
  787             IN6_IS_ADDR_V4MAPPED(&ip6->ip6_dst)) {
  788                 ip6stat.ip6s_badscope++;
  789                 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
  790                 goto bad;
  791         }
  792 
  793         /*
  794          * Tell launch routine the next header
  795          */
  796         ip6stat.ip6s_delivered++;
  797         in6_ifstat_inc(deliverifp, ifs6_in_deliver);
  798         nest = 0;
  799 
  800         while (nxt != IPPROTO_DONE) {
  801                 if (ip6_hdrnestlimit && (++nest > ip6_hdrnestlimit)) {
  802                         ip6stat.ip6s_toomanyhdr++;
  803                         goto bad;
  804                 }
  805 
  806                 /*
  807                  * protection against faulty packet - there should be
  808                  * more sanity checks in header chain processing.
  809                  */
  810                 if (m->m_pkthdr.len < off) {
  811                         ip6stat.ip6s_tooshort++;
  812                         in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_truncated);
  813                         goto bad;
  814                 }
  815 
  816 #if 0
  817                 /*
  818                  * do we need to do it for every header?  yeah, other
  819                  * functions can play with it (like re-allocate and copy).
  820                  */
  821                 mhist = ip6_addaux(m);
  822                 if (mhist && M_TRAILINGSPACE(mhist) >= sizeof(nxt)) {
  823                         hist = mtod(mhist, caddr_t) + mhist->m_len;
  824                         bcopy(&nxt, hist, sizeof(nxt));
  825                         mhist->m_len += sizeof(nxt);
  826                 } else {
  827                         ip6stat.ip6s_toomanyhdr++;
  828                         goto bad;
  829                 }
  830 #endif
  831 
  832 #ifdef IPSEC
  833                 /*
  834                  * enforce IPsec policy checking if we are seeing last header.
  835                  * note that we do not visit this with protocols with pcb layer
  836                  * code - like udp/tcp/raw ip.
  837                  */
  838                 if ((inet6sw[ip6_protox[nxt]].pr_flags & PR_LASTHDR) != 0 &&
  839                     ipsec6_in_reject(m, NULL)) {
  840                         ipsec6stat.in_polvio++;
  841                         goto bad;
  842                 }
  843 #endif
  844 
  845                 nxt = (*inet6sw[ip6_protox[nxt]].pr_input)(&m, &off, nxt);
  846         }
  847         return;
  848  bad:
  849         m_freem(m);
  850 }
  851 
  852 /*
  853  * set/grab in6_ifaddr correspond to IPv6 destination address.
  854  * XXX backward compatibility wrapper
  855  */
  856 static struct ip6aux *
  857 ip6_setdstifaddr(m, ia6)
  858         struct mbuf *m;
  859         struct in6_ifaddr *ia6;
  860 {
  861         struct ip6aux *n;
  862 
  863         n = ip6_addaux(m);
  864         if (n)
  865                 n->ip6a_dstia6 = ia6;
  866         return n;       /* NULL if failed to set */
  867 }
  868 
  869 struct in6_ifaddr *
  870 ip6_getdstifaddr(m)
  871         struct mbuf *m;
  872 {
  873         struct ip6aux *n;
  874 
  875         n = ip6_findaux(m);
  876         if (n)
  877                 return n->ip6a_dstia6;
  878         else
  879                 return NULL;
  880 }
  881 
  882 /*
  883  * Hop-by-Hop options header processing. If a valid jumbo payload option is
  884  * included, the real payload length will be stored in plenp.
  885  */
  886 static int
  887 ip6_hopopts_input(plenp, rtalertp, mp, offp)
  888         u_int32_t *plenp;
  889         u_int32_t *rtalertp;    /* XXX: should be stored more smart way */
  890         struct mbuf **mp;
  891         int *offp;
  892 {
  893         struct mbuf *m = *mp;
  894         int off = *offp, hbhlen;
  895         struct ip6_hbh *hbh;
  896         u_int8_t *opt;
  897 
  898         /* validation of the length of the header */
  899 #ifndef PULLDOWN_TEST
  900         IP6_EXTHDR_CHECK(m, off, sizeof(*hbh), -1);
  901         hbh = (struct ip6_hbh *)(mtod(m, caddr_t) + off);
  902         hbhlen = (hbh->ip6h_len + 1) << 3;
  903 
  904         IP6_EXTHDR_CHECK(m, off, hbhlen, -1);
  905         hbh = (struct ip6_hbh *)(mtod(m, caddr_t) + off);
  906 #else
  907         IP6_EXTHDR_GET(hbh, struct ip6_hbh *, m,
  908                 sizeof(struct ip6_hdr), sizeof(struct ip6_hbh));
  909         if (hbh == NULL) {
  910                 ip6stat.ip6s_tooshort++;
  911                 return -1;
  912         }
  913         hbhlen = (hbh->ip6h_len + 1) << 3;
  914         IP6_EXTHDR_GET(hbh, struct ip6_hbh *, m, sizeof(struct ip6_hdr),
  915                 hbhlen);
  916         if (hbh == NULL) {
  917                 ip6stat.ip6s_tooshort++;
  918                 return -1;
  919         }
  920 #endif
  921         off += hbhlen;
  922         hbhlen -= sizeof(struct ip6_hbh);
  923         opt = (u_int8_t *)hbh + sizeof(struct ip6_hbh);
  924 
  925         if (ip6_process_hopopts(m, (u_int8_t *)hbh + sizeof(struct ip6_hbh),
  926                                 hbhlen, rtalertp, plenp) < 0)
  927                 return(-1);
  928 
  929         *offp = off;
  930         *mp = m;
  931         return(0);
  932 }
  933 
  934 /*
  935  * Search header for all Hop-by-hop options and process each option.
  936  * This function is separate from ip6_hopopts_input() in order to
  937  * handle a case where the sending node itself process its hop-by-hop
  938  * options header. In such a case, the function is called from ip6_output().
  939  *
  940  * The function assumes that hbh header is located right after the IPv6 header
  941  * (RFC2460 p7), opthead is pointer into data content in m, and opthead to
  942  * opthead + hbhlen is located in continuous memory region.
  943  */
  944 int
  945 ip6_process_hopopts(m, opthead, hbhlen, rtalertp, plenp)
  946         struct mbuf *m;
  947         u_int8_t *opthead;
  948         int hbhlen;
  949         u_int32_t *rtalertp;
  950         u_int32_t *plenp;
  951 {
  952         struct ip6_hdr *ip6;
  953         int optlen = 0;
  954         u_int8_t *opt = opthead;
  955         u_int16_t rtalert_val;
  956         u_int32_t jumboplen;
  957         const int erroff = sizeof(struct ip6_hdr) + sizeof(struct ip6_hbh);
  958 
  959         for (; hbhlen > 0; hbhlen -= optlen, opt += optlen) {
  960                 switch (*opt) {
  961                 case IP6OPT_PAD1:
  962                         optlen = 1;
  963                         break;
  964                 case IP6OPT_PADN:
  965                         if (hbhlen < IP6OPT_MINLEN) {
  966                                 ip6stat.ip6s_toosmall++;
  967                                 goto bad;
  968                         }
  969                         optlen = *(opt + 1) + 2;
  970                         break;
  971                 case IP6OPT_RTALERT:
  972                         /* XXX may need check for alignment */
  973                         if (hbhlen < IP6OPT_RTALERT_LEN) {
  974                                 ip6stat.ip6s_toosmall++;
  975                                 goto bad;
  976                         }
  977                         if (*(opt + 1) != IP6OPT_RTALERT_LEN - 2) {
  978                                 /* XXX stat */
  979                                 icmp6_error(m, ICMP6_PARAM_PROB,
  980                                             ICMP6_PARAMPROB_HEADER,
  981                                             erroff + opt + 1 - opthead);
  982                                 return(-1);
  983                         }
  984                         optlen = IP6OPT_RTALERT_LEN;
  985                         bcopy((caddr_t)(opt + 2), (caddr_t)&rtalert_val, 2);
  986                         *rtalertp = ntohs(rtalert_val);
  987                         break;
  988                 case IP6OPT_JUMBO:
  989                         /* XXX may need check for alignment */
  990                         if (hbhlen < IP6OPT_JUMBO_LEN) {
  991                                 ip6stat.ip6s_toosmall++;
  992                                 goto bad;
  993                         }
  994                         if (*(opt + 1) != IP6OPT_JUMBO_LEN - 2) {
  995                                 /* XXX stat */
  996                                 icmp6_error(m, ICMP6_PARAM_PROB,
  997                                             ICMP6_PARAMPROB_HEADER,
  998                                             erroff + opt + 1 - opthead);
  999                                 return(-1);
 1000                         }
 1001                         optlen = IP6OPT_JUMBO_LEN;
 1002 
 1003                         /*
 1004                          * IPv6 packets that have non 0 payload length
 1005                          * must not contain a jumbo payload option.
 1006                          */
 1007                         ip6 = mtod(m, struct ip6_hdr *);
 1008                         if (ip6->ip6_plen) {
 1009                                 ip6stat.ip6s_badoptions++;
 1010                                 icmp6_error(m, ICMP6_PARAM_PROB,
 1011                                             ICMP6_PARAMPROB_HEADER,
 1012                                             erroff + opt - opthead);
 1013                                 return(-1);
 1014                         }
 1015 
 1016                         /*
 1017                          * We may see jumbolen in unaligned location, so
 1018                          * we'd need to perform bcopy().
 1019                          */
 1020                         bcopy(opt + 2, &jumboplen, sizeof(jumboplen));
 1021                         jumboplen = (u_int32_t)htonl(jumboplen);
 1022 
 1023 #if 1
 1024                         /*
 1025                          * if there are multiple jumbo payload options,
 1026                          * *plenp will be non-zero and the packet will be
 1027                          * rejected.
 1028                          * the behavior may need some debate in ipngwg -
 1029                          * multiple options does not make sense, however,
 1030                          * there's no explicit mention in specification.
 1031                          */
 1032                         if (*plenp != 0) {
 1033                                 ip6stat.ip6s_badoptions++;
 1034                                 icmp6_error(m, ICMP6_PARAM_PROB,
 1035                                             ICMP6_PARAMPROB_HEADER,
 1036                                             erroff + opt + 2 - opthead);
 1037                                 return(-1);
 1038                         }
 1039 #endif
 1040 
 1041                         /*
 1042                          * jumbo payload length must be larger than 65535.
 1043                          */
 1044                         if (jumboplen <= IPV6_MAXPACKET) {
 1045                                 ip6stat.ip6s_badoptions++;
 1046                                 icmp6_error(m, ICMP6_PARAM_PROB,
 1047                                             ICMP6_PARAMPROB_HEADER,
 1048                                             erroff + opt + 2 - opthead);
 1049                                 return(-1);
 1050                         }
 1051                         *plenp = jumboplen;
 1052 
 1053                         break;
 1054                 default:                /* unknown option */
 1055                         if (hbhlen < IP6OPT_MINLEN) {
 1056                                 ip6stat.ip6s_toosmall++;
 1057                                 goto bad;
 1058                         }
 1059                         optlen = ip6_unknown_opt(opt, m,
 1060                             erroff + opt - opthead);
 1061                         if (optlen == -1)
 1062                                 return(-1);
 1063                         optlen += 2;
 1064                         break;
 1065                 }
 1066         }
 1067 
 1068         return(0);
 1069 
 1070   bad:
 1071         m_freem(m);
 1072         return(-1);
 1073 }
 1074 
 1075 /*
 1076  * Unknown option processing.
 1077  * The third argument `off' is the offset from the IPv6 header to the option,
 1078  * which is necessary if the IPv6 header the and option header and IPv6 header
 1079  * is not continuous in order to return an ICMPv6 error.
 1080  */
 1081 int
 1082 ip6_unknown_opt(optp, m, off)
 1083         u_int8_t *optp;
 1084         struct mbuf *m;
 1085         int off;
 1086 {
 1087         struct ip6_hdr *ip6;
 1088 
 1089         switch (IP6OPT_TYPE(*optp)) {
 1090         case IP6OPT_TYPE_SKIP: /* ignore the option */
 1091                 return((int)*(optp + 1));
 1092         case IP6OPT_TYPE_DISCARD:       /* silently discard */
 1093                 m_freem(m);
 1094                 return(-1);
 1095         case IP6OPT_TYPE_FORCEICMP: /* send ICMP even if multicasted */
 1096                 ip6stat.ip6s_badoptions++;
 1097                 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_OPTION, off);
 1098                 return(-1);
 1099         case IP6OPT_TYPE_ICMP: /* send ICMP if not multicasted */
 1100                 ip6stat.ip6s_badoptions++;
 1101                 ip6 = mtod(m, struct ip6_hdr *);
 1102                 if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) ||
 1103                     (m->m_flags & (M_BCAST|M_MCAST)))
 1104                         m_freem(m);
 1105                 else
 1106                         icmp6_error(m, ICMP6_PARAM_PROB,
 1107                                     ICMP6_PARAMPROB_OPTION, off);
 1108                 return(-1);
 1109         }
 1110 
 1111         m_freem(m);             /* XXX: NOTREACHED */
 1112         return(-1);
 1113 }
 1114 
 1115 /*
 1116  * Create the "control" list for this pcb.
 1117  * The function will not modify mbuf chain at all.
 1118  *
 1119  * with KAME mbuf chain restriction:
 1120  * The routine will be called from upper layer handlers like tcp6_input().
 1121  * Thus the routine assumes that the caller (tcp6_input) have already
 1122  * called IP6_EXTHDR_CHECK() and all the extension headers are located in the
 1123  * very first mbuf on the mbuf chain.
 1124  */
 1125 void
 1126 ip6_savecontrol(in6p, mp, ip6, m)
 1127         struct inpcb *in6p;
 1128         struct mbuf **mp;
 1129         struct ip6_hdr *ip6;
 1130         struct mbuf *m;
 1131 {
 1132         int rthdr_exist = 0;
 1133 
 1134 #ifdef SO_TIMESTAMP
 1135         if ((in6p->in6p_socket->so_options & SO_TIMESTAMP) != 0) {
 1136                 struct timeval tv;
 1137 
 1138                 microtime(&tv);
 1139                 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv),
 1140                                       SCM_TIMESTAMP, SOL_SOCKET);
 1141                 if (*mp) {
 1142                         mp = &(*mp)->m_next;
 1143                 }
 1144         }
 1145 #endif
 1146 
 1147         /* RFC 2292 sec. 5 */
 1148         if ((in6p->in6p_flags & IN6P_PKTINFO) != 0) {
 1149                 struct in6_pktinfo pi6;
 1150                 bcopy(&ip6->ip6_dst, &pi6.ipi6_addr, sizeof(struct in6_addr));
 1151                 if (IN6_IS_SCOPE_LINKLOCAL(&pi6.ipi6_addr))
 1152                         pi6.ipi6_addr.s6_addr16[1] = 0;
 1153                 pi6.ipi6_ifindex = (m && m->m_pkthdr.rcvif)
 1154                                         ? m->m_pkthdr.rcvif->if_index
 1155                                         : 0;
 1156                 *mp = sbcreatecontrol((caddr_t) &pi6,
 1157                         sizeof(struct in6_pktinfo), IPV6_PKTINFO,
 1158                         IPPROTO_IPV6);
 1159                 if (*mp)
 1160                         mp = &(*mp)->m_next;
 1161         }
 1162 
 1163         if ((in6p->in6p_flags & IN6P_HOPLIMIT) != 0) {
 1164                 int hlim = ip6->ip6_hlim & 0xff;
 1165                 *mp = sbcreatecontrol((caddr_t) &hlim,
 1166                         sizeof(int), IPV6_HOPLIMIT, IPPROTO_IPV6);
 1167                 if (*mp)
 1168                         mp = &(*mp)->m_next;
 1169         }
 1170 
 1171         /*
 1172          * IPV6_HOPOPTS socket option.  Recall that we required super-user
 1173          * privilege for the option (see ip6_ctloutput), but it might be too
 1174          * strict, since there might be some hop-by-hop options which can be
 1175          * returned to normal user.
 1176          * See also RFC 2292 section 6.
 1177          */
 1178         if ((in6p->in6p_flags & IN6P_HOPOPTS) != 0) {
 1179                 /*
 1180                  * Check if a hop-by-hop options header is contatined in the
 1181                  * received packet, and if so, store the options as ancillary
 1182                  * data. Note that a hop-by-hop options header must be
 1183                  * just after the IPv6 header, which fact is assured through
 1184                  * the IPv6 input processing.
 1185                  */
 1186                 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
 1187                 if (ip6->ip6_nxt == IPPROTO_HOPOPTS) {
 1188                         struct ip6_hbh *hbh;
 1189                         int hbhlen = 0;
 1190 #ifdef PULLDOWN_TEST
 1191                         struct mbuf *ext;
 1192 #endif
 1193 
 1194 #ifndef PULLDOWN_TEST
 1195                         hbh = (struct ip6_hbh *)(ip6 + 1);
 1196                         hbhlen = (hbh->ip6h_len + 1) << 3;
 1197 #else
 1198                         ext = ip6_pullexthdr(m, sizeof(struct ip6_hdr),
 1199                             ip6->ip6_nxt);
 1200                         if (ext == NULL) {
 1201                                 ip6stat.ip6s_tooshort++;
 1202                                 return;
 1203                         }
 1204                         hbh = mtod(ext, struct ip6_hbh *);
 1205                         hbhlen = (hbh->ip6h_len + 1) << 3;
 1206                         if (hbhlen != ext->m_len) {
 1207                                 m_freem(ext);
 1208                                 ip6stat.ip6s_tooshort++;
 1209                                 return;
 1210                         }
 1211 #endif
 1212 
 1213                         /*
 1214                          * XXX: We copy whole the header even if a jumbo
 1215                          * payload option is included, which option is to
 1216                          * be removed before returning in the RFC 2292.
 1217                          * Note: this constraint is removed in 2292bis.
 1218                          */
 1219                         *mp = sbcreatecontrol((caddr_t)hbh, hbhlen,
 1220                                               IPV6_HOPOPTS, IPPROTO_IPV6);
 1221                         if (*mp)
 1222                                 mp = &(*mp)->m_next;
 1223 #ifdef PULLDOWN_TEST
 1224                         m_freem(ext);
 1225 #endif
 1226                 }
 1227         }
 1228 
 1229         /* IPV6_DSTOPTS and IPV6_RTHDR socket options */
 1230         if ((in6p->in6p_flags & (IN6P_DSTOPTS | IN6P_RTHDRDSTOPTS)) != 0) {
 1231                 int proto, off, nxt;
 1232 
 1233                 /*
 1234                  * go through the header chain to see if a routing header is
 1235                  * contained in the packet. We need this information to store
 1236                  * destination options headers (if any) properly.
 1237                  * XXX: performance issue. We should record this info when
 1238                  * processing extension headers in incoming routine.
 1239                  * (todo) use m_aux? 
 1240                  */
 1241                 proto = IPPROTO_IPV6;
 1242                 off = 0;
 1243                 nxt = -1;
 1244                 while (1) {
 1245                         int newoff;
 1246 
 1247                         newoff = ip6_nexthdr(m, off, proto, &nxt);
 1248                         if (newoff < 0)
 1249                                 break;
 1250                         if (newoff < off) /* invalid, check for safety */
 1251                                 break;
 1252                         if ((proto = nxt) == IPPROTO_ROUTING) {
 1253                                 rthdr_exist = 1;
 1254                                 break;
 1255                         }
 1256                         off = newoff;
 1257                 }
 1258         }
 1259 
 1260         if ((in6p->in6p_flags &
 1261              (IN6P_RTHDR | IN6P_DSTOPTS | IN6P_RTHDRDSTOPTS)) != 0) {
 1262                 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
 1263                 int nxt = ip6->ip6_nxt, off = sizeof(struct ip6_hdr);
 1264 
 1265                 /*
 1266                  * Search for destination options headers or routing
 1267                  * header(s) through the header chain, and stores each
 1268                  * header as ancillary data.
 1269                  * Note that the order of the headers remains in
 1270                  * the chain of ancillary data.
 1271                  */
 1272                 while (1) {     /* is explicit loop prevention necessary? */
 1273                         struct ip6_ext *ip6e = NULL;
 1274                         int elen;
 1275 #ifdef PULLDOWN_TEST
 1276                         struct mbuf *ext = NULL;
 1277 #endif
 1278 
 1279                         /*
 1280                          * if it is not an extension header, don't try to
 1281                          * pull it from the chain.
 1282                          */
 1283                         switch (nxt) {
 1284                         case IPPROTO_DSTOPTS:
 1285                         case IPPROTO_ROUTING:
 1286                         case IPPROTO_HOPOPTS:
 1287                         case IPPROTO_AH: /* is it possible? */
 1288                                 break;
 1289                         default:
 1290                                 goto loopend;
 1291                         }
 1292 
 1293 #ifndef PULLDOWN_TEST
 1294                         if (off + sizeof(*ip6e) > m->m_len)
 1295                                 goto loopend;
 1296                         ip6e = (struct ip6_ext *)(mtod(m, caddr_t) + off);
 1297                         if (nxt == IPPROTO_AH)
 1298                                 elen = (ip6e->ip6e_len + 2) << 2;
 1299                         else
 1300                                 elen = (ip6e->ip6e_len + 1) << 3;
 1301                         if (off + elen > m->m_len)
 1302                                 goto loopend;
 1303 #else
 1304                         ext = ip6_pullexthdr(m, off, nxt);
 1305                         if (ext == NULL) {
 1306                                 ip6stat.ip6s_tooshort++;
 1307                                 return;
 1308                         }
 1309                         ip6e = mtod(ext, struct ip6_ext *);
 1310                         if (nxt == IPPROTO_AH)
 1311                                 elen = (ip6e->ip6e_len + 2) << 2;
 1312                         else
 1313                                 elen = (ip6e->ip6e_len + 1) << 3;
 1314                         if (elen != ext->m_len) {
 1315                                 m_freem(ext);
 1316                                 ip6stat.ip6s_tooshort++;
 1317                                 return;
 1318                         }
 1319 #endif
 1320 
 1321                         switch (nxt) {
 1322                         case IPPROTO_DSTOPTS:
 1323                                 if ((in6p->in6p_flags & IN6P_DSTOPTS) == 0)
 1324                                         break;
 1325 
 1326                                 *mp = sbcreatecontrol((caddr_t)ip6e, elen,
 1327                                                       IPV6_DSTOPTS,
 1328                                                       IPPROTO_IPV6);
 1329                                 if (*mp)
 1330                                         mp = &(*mp)->m_next;
 1331                                 break;
 1332                         case IPPROTO_ROUTING:
 1333                                 if (!in6p->in6p_flags & IN6P_RTHDR)
 1334                                         break;
 1335 
 1336                                 *mp = sbcreatecontrol((caddr_t)ip6e, elen,
 1337                                                       IPV6_RTHDR,
 1338                                                       IPPROTO_IPV6);
 1339                                 if (*mp)
 1340                                         mp = &(*mp)->m_next;
 1341                                 break;
 1342                         case IPPROTO_HOPOPTS:
 1343                         case IPPROTO_AH: /* is it possible? */
 1344                                 break;
 1345 
 1346                         default:
 1347                                 /*
 1348                                  * other cases have been filtered in the above.
 1349                                  * none will visit this case.  here we supply
 1350                                  * the code just in case (nxt overwritten or
 1351                                  * other cases).
 1352                                  */
 1353 #ifdef PULLDOWN_TEST
 1354                                 m_freem(ext);
 1355 #endif
 1356                                 goto loopend;
 1357 
 1358                         }
 1359 
 1360                         /* proceed with the next header. */
 1361                         off += elen;
 1362                         nxt = ip6e->ip6e_nxt;
 1363                         ip6e = NULL;
 1364 #ifdef PULLDOWN_TEST
 1365                         m_freem(ext);
 1366                         ext = NULL;
 1367 #endif
 1368                 }
 1369           loopend:
 1370                 ;
 1371         }
 1372 
 1373 }
 1374 
 1375 #ifdef PULLDOWN_TEST
 1376 /*
 1377  * pull single extension header from mbuf chain.  returns single mbuf that
 1378  * contains the result, or NULL on error.
 1379  */
 1380 static struct mbuf *
 1381 ip6_pullexthdr(m, off, nxt)
 1382         struct mbuf *m;
 1383         size_t off;
 1384         int nxt;
 1385 {
 1386         struct ip6_ext ip6e;
 1387         size_t elen;
 1388         struct mbuf *n;
 1389 
 1390 #ifdef DIAGNOSTIC
 1391         switch (nxt) {
 1392         case IPPROTO_DSTOPTS:
 1393         case IPPROTO_ROUTING:
 1394         case IPPROTO_HOPOPTS:
 1395         case IPPROTO_AH: /* is it possible? */
 1396                 break;
 1397         default:
 1398                 printf("ip6_pullexthdr: invalid nxt=%d\n", nxt);
 1399         }
 1400 #endif
 1401 
 1402         m_copydata(m, off, sizeof(ip6e), (caddr_t)&ip6e);
 1403         if (nxt == IPPROTO_AH)
 1404                 elen = (ip6e.ip6e_len + 2) << 2;
 1405         else
 1406                 elen = (ip6e.ip6e_len + 1) << 3;
 1407 
 1408         MGET(n, M_DONTWAIT, MT_DATA);
 1409         if (n && elen >= MLEN) {
 1410                 MCLGET(n, M_DONTWAIT);
 1411                 if ((n->m_flags & M_EXT) == 0) {
 1412                         m_free(n);
 1413                         n = NULL;
 1414                 }
 1415         }
 1416         if (!n)
 1417                 return NULL;
 1418 
 1419         n->m_len = 0;
 1420         if (elen >= M_TRAILINGSPACE(n)) {
 1421                 m_free(n);
 1422                 return NULL;
 1423         }
 1424 
 1425         m_copydata(m, off, elen, mtod(n, caddr_t));
 1426         n->m_len = elen;
 1427         return n;
 1428 }
 1429 #endif
 1430 
 1431 /*
 1432  * Get pointer to the previous header followed by the header
 1433  * currently processed.
 1434  * XXX: This function supposes that
 1435  *      M includes all headers,
 1436  *      the next header field and the header length field of each header
 1437  *      are valid, and
 1438  *      the sum of each header length equals to OFF.
 1439  * Because of these assumptions, this function must be called very
 1440  * carefully. Moreover, it will not be used in the near future when
 1441  * we develop `neater' mechanism to process extension headers.
 1442  */
 1443 char *
 1444 ip6_get_prevhdr(m, off)
 1445         struct mbuf *m;
 1446         int off;
 1447 {
 1448         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
 1449 
 1450         if (off == sizeof(struct ip6_hdr))
 1451                 return(&ip6->ip6_nxt);
 1452         else {
 1453                 int len, nxt;
 1454                 struct ip6_ext *ip6e = NULL;
 1455 
 1456                 nxt = ip6->ip6_nxt;
 1457                 len = sizeof(struct ip6_hdr);
 1458                 while (len < off) {
 1459                         ip6e = (struct ip6_ext *)(mtod(m, caddr_t) + len);
 1460 
 1461                         switch (nxt) {
 1462                         case IPPROTO_FRAGMENT:
 1463                                 len += sizeof(struct ip6_frag);
 1464                                 break;
 1465                         case IPPROTO_AH:
 1466                                 len += (ip6e->ip6e_len + 2) << 2;
 1467                                 break;
 1468                         default:
 1469                                 len += (ip6e->ip6e_len + 1) << 3;
 1470                                 break;
 1471                         }
 1472                         nxt = ip6e->ip6e_nxt;
 1473                 }
 1474                 if (ip6e)
 1475                         return(&ip6e->ip6e_nxt);
 1476                 else
 1477                         return NULL;
 1478         }
 1479 }
 1480 
 1481 /*
 1482  * get next header offset.  m will be retained.
 1483  */
 1484 int
 1485 ip6_nexthdr(m, off, proto, nxtp)
 1486         struct mbuf *m;
 1487         int off;
 1488         int proto;
 1489         int *nxtp;
 1490 {
 1491         struct ip6_hdr ip6;
 1492         struct ip6_ext ip6e;
 1493         struct ip6_frag fh;
 1494 
 1495         /* just in case */
 1496         if (m == NULL)
 1497                 panic("ip6_nexthdr: m == NULL");
 1498         if ((m->m_flags & M_PKTHDR) == 0 || m->m_pkthdr.len < off)
 1499                 return -1;
 1500 
 1501         switch (proto) {
 1502         case IPPROTO_IPV6:
 1503                 if (m->m_pkthdr.len < off + sizeof(ip6))
 1504                         return -1;
 1505                 m_copydata(m, off, sizeof(ip6), (caddr_t)&ip6);
 1506                 if (nxtp)
 1507                         *nxtp = ip6.ip6_nxt;
 1508                 off += sizeof(ip6);
 1509                 return off;
 1510 
 1511         case IPPROTO_FRAGMENT:
 1512                 /*
 1513                  * terminate parsing if it is not the first fragment,
 1514                  * it does not make sense to parse through it.
 1515                  */
 1516                 if (m->m_pkthdr.len < off + sizeof(fh))
 1517                         return -1;
 1518                 m_copydata(m, off, sizeof(fh), (caddr_t)&fh);
 1519                 if ((ntohs(fh.ip6f_offlg) & IP6F_OFF_MASK) != 0)
 1520                         return -1;
 1521                 if (nxtp)
 1522                         *nxtp = fh.ip6f_nxt;
 1523                 off += sizeof(struct ip6_frag);
 1524                 return off;
 1525 
 1526         case IPPROTO_AH:
 1527                 if (m->m_pkthdr.len < off + sizeof(ip6e))
 1528                         return -1;
 1529                 m_copydata(m, off, sizeof(ip6e), (caddr_t)&ip6e);
 1530                 if (nxtp)
 1531                         *nxtp = ip6e.ip6e_nxt;
 1532                 off += (ip6e.ip6e_len + 2) << 2;
 1533                 return off;
 1534 
 1535         case IPPROTO_HOPOPTS:
 1536         case IPPROTO_ROUTING:
 1537         case IPPROTO_DSTOPTS:
 1538                 if (m->m_pkthdr.len < off + sizeof(ip6e))
 1539                         return -1;
 1540                 m_copydata(m, off, sizeof(ip6e), (caddr_t)&ip6e);
 1541                 if (nxtp)
 1542                         *nxtp = ip6e.ip6e_nxt;
 1543                 off += (ip6e.ip6e_len + 1) << 3;
 1544                 return off;
 1545 
 1546         case IPPROTO_NONE:
 1547         case IPPROTO_ESP:
 1548         case IPPROTO_IPCOMP:
 1549                 /* give up */
 1550                 return -1;
 1551 
 1552         default:
 1553                 return -1;
 1554         }
 1555 
 1556         return -1;
 1557 }
 1558 
 1559 /*
 1560  * get offset for the last header in the chain.  m will be kept untainted.
 1561  */
 1562 int
 1563 ip6_lasthdr(m, off, proto, nxtp)
 1564         struct mbuf *m;
 1565         int off;
 1566         int proto;
 1567         int *nxtp;
 1568 {
 1569         int newoff;
 1570         int nxt;
 1571 
 1572         if (!nxtp) {
 1573                 nxt = -1;
 1574                 nxtp = &nxt;
 1575         }
 1576         while (1) {
 1577                 newoff = ip6_nexthdr(m, off, proto, nxtp);
 1578                 if (newoff < 0)
 1579                         return off;
 1580                 else if (newoff < off)
 1581                         return -1;      /* invalid */
 1582                 else if (newoff == off)
 1583                         return newoff;
 1584 
 1585                 off = newoff;
 1586                 proto = *nxtp;
 1587         }
 1588 }
 1589 
 1590 struct ip6aux *
 1591 ip6_addaux(m)
 1592         struct mbuf *m;
 1593 {
 1594         struct m_tag *tag = m_tag_find(m, PACKET_TAG_IPV6_INPUT, NULL);
 1595         if (!tag) {
 1596                 tag = m_tag_get(PACKET_TAG_IPV6_INPUT,
 1597                                 sizeof (struct ip6aux),
 1598                                 M_NOWAIT);
 1599                 if (tag)
 1600                         m_tag_prepend(m, tag);
 1601         }
 1602         if (tag)
 1603                 bzero(tag+1, sizeof (struct ip6aux));
 1604         return tag ? (struct ip6aux*)(tag+1) : NULL;
 1605 }
 1606 
 1607 struct ip6aux *
 1608 ip6_findaux(m)
 1609         struct mbuf *m;
 1610 {
 1611         struct m_tag *tag = m_tag_find(m, PACKET_TAG_IPV6_INPUT, NULL);
 1612         return tag ? (struct ip6aux*)(tag+1) : NULL;
 1613 }
 1614 
 1615 void
 1616 ip6_delaux(m)
 1617         struct mbuf *m;
 1618 {
 1619         struct m_tag *tag = m_tag_find(m, PACKET_TAG_IPV6_INPUT, NULL);
 1620         if (tag)
 1621                 m_tag_delete(m, tag);
 1622 }
 1623 
 1624 /*
 1625  * System control for IP6
 1626  */
 1627 
 1628 u_char  inet6ctlerrmap[PRC_NCMDS] = {
 1629         0,              0,              0,              0,
 1630         0,              EMSGSIZE,       EHOSTDOWN,      EHOSTUNREACH,
 1631         EHOSTUNREACH,   EHOSTUNREACH,   ECONNREFUSED,   ECONNREFUSED,
 1632         EMSGSIZE,       EHOSTUNREACH,   0,              0,
 1633         0,              0,              0,              0,
 1634         ENOPROTOOPT
 1635 };

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