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sys/netinet6/nd6_nbr.c

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    1 /*      $FreeBSD: src/sys/netinet6/nd6_nbr.c,v 1.13 2002/10/16 01:54:45 sam Exp $       */
    2 /*      $KAME: nd6_nbr.c,v 1.86 2002/01/21 02:33:04 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 #include "opt_inet.h"
   34 #include "opt_inet6.h"
   35 #include "opt_ipsec.h"
   36 
   37 #include <sys/param.h>
   38 #include <sys/systm.h>
   39 #include <sys/malloc.h>
   40 #include <sys/mbuf.h>
   41 #include <sys/socket.h>
   42 #include <sys/sockio.h>
   43 #include <sys/time.h>
   44 #include <sys/kernel.h>
   45 #include <sys/errno.h>
   46 #include <sys/syslog.h>
   47 #include <sys/queue.h>
   48 #include <sys/callout.h>
   49 
   50 #include <net/if.h>
   51 #include <net/if_types.h>
   52 #include <net/if_dl.h>
   53 #include <net/route.h>
   54 
   55 #include <netinet/in.h>
   56 #include <netinet/in_var.h>
   57 #include <netinet6/in6_var.h>
   58 #include <netinet/ip6.h>
   59 #include <netinet6/ip6_var.h>
   60 #include <netinet6/nd6.h>
   61 #include <netinet/icmp6.h>
   62 
   63 #ifdef IPSEC
   64 #include <netinet6/ipsec.h>
   65 #ifdef INET6
   66 #include <netinet6/ipsec6.h>
   67 #endif
   68 #endif
   69 
   70 #include <net/net_osdep.h>
   71 
   72 #define SDL(s) ((struct sockaddr_dl *)s)
   73 
   74 struct dadq;
   75 static struct dadq *nd6_dad_find __P((struct ifaddr *));
   76 static void nd6_dad_starttimer __P((struct dadq *, int));
   77 static void nd6_dad_stoptimer __P((struct dadq *));
   78 static void nd6_dad_timer __P((struct ifaddr *));
   79 static void nd6_dad_ns_output __P((struct dadq *, struct ifaddr *));
   80 static void nd6_dad_ns_input __P((struct ifaddr *));
   81 static void nd6_dad_na_input __P((struct ifaddr *));
   82 
   83 static int dad_ignore_ns = 0;   /* ignore NS in DAD - specwise incorrect*/
   84 static int dad_maxtry = 15;     /* max # of *tries* to transmit DAD packet */
   85 
   86 /*
   87  * Input an Neighbor Solicitation Message.
   88  *
   89  * Based on RFC 2461
   90  * Based on RFC 2462 (duplicated address detection)
   91  */
   92 void
   93 nd6_ns_input(m, off, icmp6len)
   94         struct mbuf *m;
   95         int off, icmp6len;
   96 {
   97         struct ifnet *ifp = m->m_pkthdr.rcvif;
   98         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
   99         struct nd_neighbor_solicit *nd_ns;
  100         struct in6_addr saddr6 = ip6->ip6_src;
  101         struct in6_addr daddr6 = ip6->ip6_dst;
  102         struct in6_addr taddr6;
  103         struct in6_addr myaddr6;
  104         char *lladdr = NULL;
  105         struct ifaddr *ifa;
  106         int lladdrlen = 0;
  107         int anycast = 0, proxy = 0, tentative = 0;
  108         int tlladdr;
  109         union nd_opts ndopts;
  110         struct sockaddr_dl *proxydl = NULL;
  111 
  112 #ifndef PULLDOWN_TEST
  113         IP6_EXTHDR_CHECK(m, off, icmp6len,);
  114         nd_ns = (struct nd_neighbor_solicit *)((caddr_t)ip6 + off);
  115 #else
  116         IP6_EXTHDR_GET(nd_ns, struct nd_neighbor_solicit *, m, off, icmp6len);
  117         if (nd_ns == NULL) {
  118                 icmp6stat.icp6s_tooshort++;
  119                 return;
  120         }
  121 #endif
  122         ip6 = mtod(m, struct ip6_hdr *); /* adjust pointer for safety */
  123         taddr6 = nd_ns->nd_ns_target;
  124 
  125         if (ip6->ip6_hlim != 255) {
  126                 nd6log((LOG_ERR,
  127                     "nd6_ns_input: invalid hlim (%d) from %s to %s on %s\n",
  128                     ip6->ip6_hlim, ip6_sprintf(&ip6->ip6_src),
  129                     ip6_sprintf(&ip6->ip6_dst), if_name(ifp)));
  130                 goto bad;
  131         }
  132 
  133         if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) {
  134                 /* dst has to be solicited node multicast address. */
  135                 if (daddr6.s6_addr16[0] == IPV6_ADDR_INT16_MLL
  136                     /* don't check ifindex portion */
  137                     && daddr6.s6_addr32[1] == 0
  138                     && daddr6.s6_addr32[2] == IPV6_ADDR_INT32_ONE
  139                     && daddr6.s6_addr8[12] == 0xff) {
  140                         ; /* good */
  141                 } else {
  142                         nd6log((LOG_INFO, "nd6_ns_input: bad DAD packet "
  143                                 "(wrong ip6 dst)\n"));
  144                         goto bad;
  145                 }
  146         }
  147 
  148         if (IN6_IS_ADDR_MULTICAST(&taddr6)) {
  149                 nd6log((LOG_INFO, "nd6_ns_input: bad NS target (multicast)\n"));
  150                 goto bad;
  151         }
  152 
  153         if (IN6_IS_SCOPE_LINKLOCAL(&taddr6))
  154                 taddr6.s6_addr16[1] = htons(ifp->if_index);
  155 
  156         icmp6len -= sizeof(*nd_ns);
  157         nd6_option_init(nd_ns + 1, icmp6len, &ndopts);
  158         if (nd6_options(&ndopts) < 0) {
  159                 nd6log((LOG_INFO,
  160                     "nd6_ns_input: invalid ND option, ignored\n"));
  161                 /* nd6_options have incremented stats */
  162                 goto freeit;
  163         }
  164 
  165         if (ndopts.nd_opts_src_lladdr) {
  166                 lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1);
  167                 lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
  168         }
  169         
  170         if (IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src) && lladdr) {
  171                 nd6log((LOG_INFO, "nd6_ns_input: bad DAD packet "
  172                     "(link-layer address option)\n"));
  173                 goto bad;
  174         }
  175 
  176         /*
  177          * Attaching target link-layer address to the NA?
  178          * (RFC 2461 7.2.4)
  179          *
  180          * NS IP dst is unicast/anycast                 MUST NOT add
  181          * NS IP dst is solicited-node multicast        MUST add
  182          *
  183          * In implementation, we add target link-layer address by default.
  184          * We do not add one in MUST NOT cases.
  185          */
  186 #if 0 /* too much! */
  187         ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &daddr6);
  188         if (ifa && (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_ANYCAST))
  189                 tlladdr = 0;
  190         else
  191 #endif
  192         if (!IN6_IS_ADDR_MULTICAST(&daddr6))
  193                 tlladdr = 0;
  194         else
  195                 tlladdr = 1;
  196 
  197         /*
  198          * Target address (taddr6) must be either:
  199          * (1) Valid unicast/anycast address for my receiving interface,
  200          * (2) Unicast address for which I'm offering proxy service, or
  201          * (3) "tentative" address on which DAD is being performed.
  202          */
  203         /* (1) and (3) check. */
  204         ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
  205 
  206         /* (2) check. */
  207         if (!ifa) {
  208                 struct rtentry *rt;
  209                 struct sockaddr_in6 tsin6;
  210 
  211                 bzero(&tsin6, sizeof tsin6);            
  212                 tsin6.sin6_len = sizeof(struct sockaddr_in6);
  213                 tsin6.sin6_family = AF_INET6;
  214                 tsin6.sin6_addr = taddr6;
  215 
  216                 rt = rtalloc1((struct sockaddr *)&tsin6, 0, 0);
  217                 if (rt && (rt->rt_flags & RTF_ANNOUNCE) != 0 &&
  218                     rt->rt_gateway->sa_family == AF_LINK) {
  219                         /*
  220                          * proxy NDP for single entry
  221                          */
  222                         ifa = (struct ifaddr *)in6ifa_ifpforlinklocal(ifp,
  223                                 IN6_IFF_NOTREADY|IN6_IFF_ANYCAST);
  224                         if (ifa) {
  225                                 proxy = 1;
  226                                 proxydl = SDL(rt->rt_gateway);
  227                         }
  228                 }
  229                 if (rt)
  230                         rtfree(rt);
  231         }
  232         if (!ifa) {
  233                 /*
  234                  * We've got an NS packet, and we don't have that adddress
  235                  * assigned for us.  We MUST silently ignore it.
  236                  * See RFC2461 7.2.3.
  237                  */
  238                 goto freeit;
  239         }
  240         myaddr6 = *IFA_IN6(ifa);
  241         anycast = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_ANYCAST;
  242         tentative = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_TENTATIVE;
  243         if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_DUPLICATED)
  244                 goto freeit;
  245 
  246         if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
  247                 nd6log((LOG_INFO,
  248                     "nd6_ns_input: lladdrlen mismatch for %s "
  249                     "(if %d, NS packet %d)\n",
  250                         ip6_sprintf(&taddr6), ifp->if_addrlen, lladdrlen - 2));
  251                 goto bad;
  252         }
  253 
  254         if (IN6_ARE_ADDR_EQUAL(&myaddr6, &saddr6)) {
  255                 nd6log((LOG_INFO,
  256                         "nd6_ns_input: duplicate IP6 address %s\n",
  257                         ip6_sprintf(&saddr6)));
  258                 goto freeit;
  259         }
  260 
  261         /*
  262          * We have neighbor solicitation packet, with target address equals to
  263          * one of my tentative address.
  264          *
  265          * src addr     how to process?
  266          * ---          ---
  267          * multicast    of course, invalid (rejected in ip6_input)
  268          * unicast      somebody is doing address resolution -> ignore
  269          * unspec       dup address detection
  270          *
  271          * The processing is defined in RFC 2462.
  272          */
  273         if (tentative) {
  274                 /*
  275                  * If source address is unspecified address, it is for
  276                  * duplicated address detection.
  277                  *
  278                  * If not, the packet is for addess resolution;
  279                  * silently ignore it.
  280                  */
  281                 if (IN6_IS_ADDR_UNSPECIFIED(&saddr6))
  282                         nd6_dad_ns_input(ifa);
  283 
  284                 goto freeit;
  285         }
  286 
  287         /*
  288          * If the source address is unspecified address, entries must not
  289          * be created or updated.
  290          * It looks that sender is performing DAD.  Output NA toward
  291          * all-node multicast address, to tell the sender that I'm using
  292          * the address.
  293          * S bit ("solicited") must be zero.
  294          */
  295         if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) {
  296                 saddr6 = in6addr_linklocal_allnodes;
  297                 saddr6.s6_addr16[1] = htons(ifp->if_index);
  298                 nd6_na_output(ifp, &saddr6, &taddr6,
  299                               ((anycast || proxy || !tlladdr)
  300                                       ? 0 : ND_NA_FLAG_OVERRIDE)
  301                                 | (ip6_forwarding ? ND_NA_FLAG_ROUTER : 0),
  302                               tlladdr, (struct sockaddr *)proxydl);
  303                 goto freeit;
  304         }
  305 
  306         nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen, ND_NEIGHBOR_SOLICIT, 0);
  307 
  308         nd6_na_output(ifp, &saddr6, &taddr6,
  309                       ((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE)
  310                         | (ip6_forwarding ? ND_NA_FLAG_ROUTER : 0)
  311                         | ND_NA_FLAG_SOLICITED,
  312                       tlladdr, (struct sockaddr *)proxydl);
  313  freeit:
  314         m_freem(m);
  315         return;
  316 
  317  bad:
  318         nd6log((LOG_ERR, "nd6_ns_input: src=%s\n", ip6_sprintf(&saddr6)));
  319         nd6log((LOG_ERR, "nd6_ns_input: dst=%s\n", ip6_sprintf(&daddr6)));
  320         nd6log((LOG_ERR, "nd6_ns_input: tgt=%s\n", ip6_sprintf(&taddr6)));
  321         icmp6stat.icp6s_badns++;
  322         m_freem(m);
  323 }
  324 
  325 /*
  326  * Output an Neighbor Solicitation Message. Caller specifies:
  327  *      - ICMP6 header source IP6 address
  328  *      - ND6 header target IP6 address
  329  *      - ND6 header source datalink address
  330  *
  331  * Based on RFC 2461
  332  * Based on RFC 2462 (duplicated address detection)
  333  */
  334 void
  335 nd6_ns_output(ifp, daddr6, taddr6, ln, dad)
  336         struct ifnet *ifp;
  337         const struct in6_addr *daddr6, *taddr6;
  338         struct llinfo_nd6 *ln;  /* for source address determination */
  339         int dad;        /* duplicated address detection */
  340 {
  341         struct mbuf *m;
  342         struct ip6_hdr *ip6;
  343         struct nd_neighbor_solicit *nd_ns;
  344         struct in6_ifaddr *ia = NULL;
  345         struct ip6_moptions im6o;
  346         int icmp6len;
  347         int maxlen;
  348         caddr_t mac;
  349         struct ifnet *outif = NULL;
  350         
  351         if (IN6_IS_ADDR_MULTICAST(taddr6))
  352                 return;
  353 
  354         /* estimate the size of message */
  355         maxlen = sizeof(*ip6) + sizeof(*nd_ns);
  356         maxlen += (sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7;
  357         if (max_linkhdr + maxlen >= MCLBYTES) {
  358 #ifdef DIAGNOSTIC
  359                 printf("nd6_ns_output: max_linkhdr + maxlen >= MCLBYTES "
  360                     "(%d + %d > %d)\n", max_linkhdr, maxlen, MCLBYTES);
  361 #endif
  362                 return;
  363         }
  364 
  365         MGETHDR(m, M_DONTWAIT, MT_DATA);
  366         if (m && max_linkhdr + maxlen >= MHLEN) {
  367                 MCLGET(m, M_DONTWAIT);
  368                 if ((m->m_flags & M_EXT) == 0) {
  369                         m_free(m);
  370                         m = NULL;
  371                 }
  372         }
  373         if (m == NULL)
  374                 return;
  375         m->m_pkthdr.rcvif = NULL;
  376 
  377         if (daddr6 == NULL || IN6_IS_ADDR_MULTICAST(daddr6)) {
  378                 m->m_flags |= M_MCAST;
  379                 im6o.im6o_multicast_ifp = ifp;
  380                 im6o.im6o_multicast_hlim = 255;
  381                 im6o.im6o_multicast_loop = 0;
  382         }
  383 
  384         icmp6len = sizeof(*nd_ns);
  385         m->m_pkthdr.len = m->m_len = sizeof(*ip6) + icmp6len;
  386         m->m_data += max_linkhdr;       /* or MH_ALIGN() equivalent? */
  387 
  388         /* fill neighbor solicitation packet */
  389         ip6 = mtod(m, struct ip6_hdr *);
  390         ip6->ip6_flow = 0;
  391         ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
  392         ip6->ip6_vfc |= IPV6_VERSION;
  393         /* ip6->ip6_plen will be set later */
  394         ip6->ip6_nxt = IPPROTO_ICMPV6;
  395         ip6->ip6_hlim = 255;
  396         if (daddr6)
  397                 ip6->ip6_dst = *daddr6;
  398         else {
  399                 ip6->ip6_dst.s6_addr16[0] = IPV6_ADDR_INT16_MLL;
  400                 ip6->ip6_dst.s6_addr16[1] = htons(ifp->if_index);
  401                 ip6->ip6_dst.s6_addr32[1] = 0;
  402                 ip6->ip6_dst.s6_addr32[2] = IPV6_ADDR_INT32_ONE;
  403                 ip6->ip6_dst.s6_addr32[3] = taddr6->s6_addr32[3];
  404                 ip6->ip6_dst.s6_addr8[12] = 0xff;
  405         }
  406         if (!dad) {
  407 #if 0   /* KAME way, exact address scope match */
  408                 /*
  409                  * Select a source whose scope is the same as that of the dest.
  410                  * Typically, the dest is link-local solicitation multicast
  411                  * (i.e. neighbor discovery) or link-local/global unicast
  412                  * (i.e. neighbor un-reachability detection).
  413                  */
  414                 ia = in6_ifawithifp(ifp, &ip6->ip6_dst);
  415                 if (ia == NULL) {
  416                         m_freem(m);
  417                         return;
  418                 }
  419                 ip6->ip6_src = ia->ia_addr.sin6_addr;
  420 #else   /* spec-wise correct */
  421                 /*
  422                  * RFC2461 7.2.2:
  423                  * "If the source address of the packet prompting the
  424                  * solicitation is the same as one of the addresses assigned
  425                  * to the outgoing interface, that address SHOULD be placed
  426                  * in the IP Source Address of the outgoing solicitation.
  427                  * Otherwise, any one of the addresses assigned to the
  428                  * interface should be used."
  429                  *
  430                  * We use the source address for the prompting packet
  431                  * (saddr6), if:
  432                  * - saddr6 is given from the caller (by giving "ln"), and
  433                  * - saddr6 belongs to the outgoing interface.
  434                  * Otherwise, we perform a scope-wise match.
  435                  */
  436                 struct ip6_hdr *hip6;           /* hold ip6 */
  437                 struct in6_addr *saddr6;
  438 
  439                 if (ln && ln->ln_hold) {
  440                         hip6 = mtod(ln->ln_hold, struct ip6_hdr *);
  441                         /* XXX pullup? */
  442                         if (sizeof(*hip6) < ln->ln_hold->m_len)
  443                                 saddr6 = &hip6->ip6_src;
  444                         else
  445                                 saddr6 = NULL;
  446                 } else
  447                         saddr6 = NULL;
  448                 if (saddr6 && in6ifa_ifpwithaddr(ifp, saddr6))
  449                         bcopy(saddr6, &ip6->ip6_src, sizeof(*saddr6));
  450                 else {
  451                         ia = in6_ifawithifp(ifp, &ip6->ip6_dst);
  452                         if (ia == NULL) {
  453                                 m_freem(m);
  454                                 return;
  455                         }
  456                         ip6->ip6_src = ia->ia_addr.sin6_addr;
  457                 }
  458 #endif
  459         } else {
  460                 /*
  461                  * Source address for DAD packet must always be IPv6
  462                  * unspecified address. (0::0)
  463                  */
  464                 bzero(&ip6->ip6_src, sizeof(ip6->ip6_src));
  465         }
  466         nd_ns = (struct nd_neighbor_solicit *)(ip6 + 1);
  467         nd_ns->nd_ns_type = ND_NEIGHBOR_SOLICIT;
  468         nd_ns->nd_ns_code = 0;
  469         nd_ns->nd_ns_reserved = 0;
  470         nd_ns->nd_ns_target = *taddr6;
  471 
  472         if (IN6_IS_SCOPE_LINKLOCAL(&nd_ns->nd_ns_target))
  473                 nd_ns->nd_ns_target.s6_addr16[1] = 0;
  474 
  475         /*
  476          * Add source link-layer address option.
  477          *
  478          *                              spec            implementation
  479          *                              ---             ---
  480          * DAD packet                   MUST NOT        do not add the option
  481          * there's no link layer address:
  482          *                              impossible      do not add the option
  483          * there's link layer address:
  484          *      Multicast NS            MUST add one    add the option
  485          *      Unicast NS              SHOULD add one  add the option
  486          */
  487         if (!dad && (mac = nd6_ifptomac(ifp))) {
  488                 int optlen = sizeof(struct nd_opt_hdr) + ifp->if_addrlen;
  489                 struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)(nd_ns + 1);
  490                 /* 8 byte alignments... */
  491                 optlen = (optlen + 7) & ~7;
  492                 
  493                 m->m_pkthdr.len += optlen;
  494                 m->m_len += optlen;
  495                 icmp6len += optlen;
  496                 bzero((caddr_t)nd_opt, optlen);
  497                 nd_opt->nd_opt_type = ND_OPT_SOURCE_LINKADDR;
  498                 nd_opt->nd_opt_len = optlen >> 3;
  499                 bcopy(mac, (caddr_t)(nd_opt + 1), ifp->if_addrlen);
  500         }
  501 
  502         ip6->ip6_plen = htons((u_short)icmp6len);
  503         nd_ns->nd_ns_cksum = 0;
  504         nd_ns->nd_ns_cksum
  505                 = in6_cksum(m, IPPROTO_ICMPV6, sizeof(*ip6), icmp6len);
  506 
  507         ip6_output(m, NULL, NULL, dad ? IPV6_DADOUTPUT : 0, &im6o, &outif, NULL);
  508         if (outif) {
  509                 icmp6_ifstat_inc(outif, ifs6_out_msg);
  510                 icmp6_ifstat_inc(outif, ifs6_out_neighborsolicit);
  511         }
  512         icmp6stat.icp6s_outhist[ND_NEIGHBOR_SOLICIT]++;
  513 }
  514 
  515 /*
  516  * Neighbor advertisement input handling.
  517  *
  518  * Based on RFC 2461
  519  * Based on RFC 2462 (duplicated address detection)
  520  *
  521  * the following items are not implemented yet:
  522  * - proxy advertisement delay rule (RFC2461 7.2.8, last paragraph, SHOULD)
  523  * - anycast advertisement delay rule (RFC2461 7.2.7, SHOULD)
  524  */
  525 void
  526 nd6_na_input(m, off, icmp6len)
  527         struct mbuf *m;
  528         int off, icmp6len;
  529 {
  530         struct ifnet *ifp = m->m_pkthdr.rcvif;
  531         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
  532         struct nd_neighbor_advert *nd_na;
  533 #if 0
  534         struct in6_addr saddr6 = ip6->ip6_src;
  535 #endif
  536         struct in6_addr daddr6 = ip6->ip6_dst;
  537         struct in6_addr taddr6;
  538         int flags;
  539         int is_router;
  540         int is_solicited;
  541         int is_override;
  542         char *lladdr = NULL;
  543         int lladdrlen = 0;
  544         struct ifaddr *ifa;
  545         struct llinfo_nd6 *ln;
  546         struct rtentry *rt;
  547         struct sockaddr_dl *sdl;
  548         union nd_opts ndopts;
  549 
  550         if (ip6->ip6_hlim != 255) {
  551                 nd6log((LOG_ERR,
  552                     "nd6_na_input: invalid hlim (%d) from %s to %s on %s\n",
  553                     ip6->ip6_hlim, ip6_sprintf(&ip6->ip6_src),
  554                     ip6_sprintf(&ip6->ip6_dst), if_name(ifp)));
  555                 goto bad;
  556         }
  557 
  558 #ifndef PULLDOWN_TEST
  559         IP6_EXTHDR_CHECK(m, off, icmp6len,);
  560         nd_na = (struct nd_neighbor_advert *)((caddr_t)ip6 + off);
  561 #else
  562         IP6_EXTHDR_GET(nd_na, struct nd_neighbor_advert *, m, off, icmp6len);
  563         if (nd_na == NULL) {
  564                 icmp6stat.icp6s_tooshort++;
  565                 return;
  566         }
  567 #endif
  568         taddr6 = nd_na->nd_na_target;
  569         flags = nd_na->nd_na_flags_reserved;
  570         is_router = ((flags & ND_NA_FLAG_ROUTER) != 0);
  571         is_solicited = ((flags & ND_NA_FLAG_SOLICITED) != 0);
  572         is_override = ((flags & ND_NA_FLAG_OVERRIDE) != 0);
  573 
  574         if (IN6_IS_SCOPE_LINKLOCAL(&taddr6))
  575                 taddr6.s6_addr16[1] = htons(ifp->if_index);
  576 
  577         if (IN6_IS_ADDR_MULTICAST(&taddr6)) {
  578                 nd6log((LOG_ERR,
  579                     "nd6_na_input: invalid target address %s\n",
  580                     ip6_sprintf(&taddr6)));
  581                 goto bad;
  582         }
  583         if (IN6_IS_ADDR_MULTICAST(&daddr6))
  584                 if (is_solicited) {
  585                         nd6log((LOG_ERR,
  586                             "nd6_na_input: a solicited adv is multicasted\n"));
  587                         goto bad;
  588                 }
  589 
  590         icmp6len -= sizeof(*nd_na);
  591         nd6_option_init(nd_na + 1, icmp6len, &ndopts);
  592         if (nd6_options(&ndopts) < 0) {
  593                 nd6log((LOG_INFO,
  594                     "nd6_na_input: invalid ND option, ignored\n"));
  595                 /* nd6_options have incremented stats */
  596                 goto freeit;
  597         }
  598 
  599         if (ndopts.nd_opts_tgt_lladdr) {
  600                 lladdr = (char *)(ndopts.nd_opts_tgt_lladdr + 1);
  601                 lladdrlen = ndopts.nd_opts_tgt_lladdr->nd_opt_len << 3;
  602         }
  603 
  604         ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
  605 
  606         /*
  607          * Target address matches one of my interface address.
  608          *
  609          * If my address is tentative, this means that there's somebody
  610          * already using the same address as mine.  This indicates DAD failure.
  611          * This is defined in RFC 2462.
  612          *
  613          * Otherwise, process as defined in RFC 2461.
  614          */
  615         if (ifa
  616          && (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_TENTATIVE)) {
  617                 nd6_dad_na_input(ifa);
  618                 goto freeit;
  619         }
  620 
  621         /* Just for safety, maybe unnecessary. */
  622         if (ifa) {
  623                 log(LOG_ERR,
  624                     "nd6_na_input: duplicate IP6 address %s\n",
  625                     ip6_sprintf(&taddr6));
  626                 goto freeit;
  627         }
  628 
  629         if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
  630                 nd6log((LOG_INFO,
  631                     "nd6_na_input: lladdrlen mismatch for %s "
  632                     "(if %d, NA packet %d)\n",
  633                         ip6_sprintf(&taddr6), ifp->if_addrlen, lladdrlen - 2));
  634                 goto bad;
  635         }
  636 
  637         /*
  638          * If no neighbor cache entry is found, NA SHOULD silently be discarded.
  639          */
  640         rt = nd6_lookup(&taddr6, 0, ifp);
  641         if ((rt == NULL) ||
  642            ((ln = (struct llinfo_nd6 *)rt->rt_llinfo) == NULL) ||
  643            ((sdl = SDL(rt->rt_gateway)) == NULL))
  644                 goto freeit;
  645 
  646         if (ln->ln_state == ND6_LLINFO_INCOMPLETE) {
  647                 /*
  648                  * If the link-layer has address, and no lladdr option came,
  649                  * discard the packet.
  650                  */
  651                 if (ifp->if_addrlen && !lladdr)
  652                         goto freeit;
  653 
  654                 /*
  655                  * Record link-layer address, and update the state.
  656                  */
  657                 sdl->sdl_alen = ifp->if_addrlen;
  658                 bcopy(lladdr, LLADDR(sdl), ifp->if_addrlen);
  659                 if (is_solicited) {
  660                         ln->ln_state = ND6_LLINFO_REACHABLE;
  661                         ln->ln_byhint = 0;
  662                         if (ln->ln_expire)
  663                                 ln->ln_expire = time_second +
  664                                     nd_ifinfo[rt->rt_ifp->if_index].reachable;
  665                 } else {
  666                         ln->ln_state = ND6_LLINFO_STALE;
  667                         ln->ln_expire = time_second + nd6_gctimer;
  668                 }
  669                 if ((ln->ln_router = is_router) != 0) {
  670                         /*
  671                          * This means a router's state has changed from
  672                          * non-reachable to probably reachable, and might
  673                          * affect the status of associated prefixes..
  674                          */
  675                         pfxlist_onlink_check();
  676                 }
  677         } else {
  678                 int llchange;
  679 
  680                 /*
  681                  * Check if the link-layer address has changed or not.
  682                  */
  683                 if (!lladdr)
  684                         llchange = 0;
  685                 else {
  686                         if (sdl->sdl_alen) {
  687                                 if (bcmp(lladdr, LLADDR(sdl), ifp->if_addrlen))
  688                                         llchange = 1;
  689                                 else
  690                                         llchange = 0;
  691                         } else
  692                                 llchange = 1;
  693                 }
  694 
  695                 /*
  696                  * This is VERY complex.  Look at it with care.
  697                  *
  698                  * override solicit lladdr llchange     action
  699                  *                                      (L: record lladdr)
  700                  *
  701                  *      0       0       n       --      (2c)
  702                  *      0       0       y       n       (2b) L
  703                  *      0       0       y       y       (1)    REACHABLE->STALE
  704                  *      0       1       n       --      (2c)   *->REACHABLE
  705                  *      0       1       y       n       (2b) L *->REACHABLE
  706                  *      0       1       y       y       (1)    REACHABLE->STALE
  707                  *      1       0       n       --      (2a)
  708                  *      1       0       y       n       (2a) L
  709                  *      1       0       y       y       (2a) L *->STALE
  710                  *      1       1       n       --      (2a)   *->REACHABLE
  711                  *      1       1       y       n       (2a) L *->REACHABLE
  712                  *      1       1       y       y       (2a) L *->REACHABLE
  713                  */
  714                 if (!is_override && (lladdr && llchange)) {        /* (1) */
  715                         /*
  716                          * If state is REACHABLE, make it STALE.
  717                          * no other updates should be done.
  718                          */
  719                         if (ln->ln_state == ND6_LLINFO_REACHABLE) {
  720                                 ln->ln_state = ND6_LLINFO_STALE;
  721                                 ln->ln_expire = time_second + nd6_gctimer;
  722                         }
  723                         goto freeit;
  724                 } else if (is_override                             /* (2a) */
  725                         || (!is_override && (lladdr && !llchange)) /* (2b) */
  726                         || !lladdr) {                              /* (2c) */
  727                         /*
  728                          * Update link-local address, if any.
  729                          */
  730                         if (lladdr) {
  731                                 sdl->sdl_alen = ifp->if_addrlen;
  732                                 bcopy(lladdr, LLADDR(sdl), ifp->if_addrlen);
  733                         }
  734 
  735                         /*
  736                          * If solicited, make the state REACHABLE.
  737                          * If not solicited and the link-layer address was
  738                          * changed, make it STALE.
  739                          */
  740                         if (is_solicited) {
  741                                 ln->ln_state = ND6_LLINFO_REACHABLE;
  742                                 ln->ln_byhint = 0;
  743                                 if (ln->ln_expire) {
  744                                         ln->ln_expire = time_second +
  745                                             nd_ifinfo[ifp->if_index].reachable;
  746                                 }
  747                         } else {
  748                                 if (lladdr && llchange) {
  749                                         ln->ln_state = ND6_LLINFO_STALE;
  750                                         ln->ln_expire = time_second + nd6_gctimer;
  751                                 }
  752                         }
  753                 }
  754 
  755                 if (ln->ln_router && !is_router) {
  756                         /*
  757                          * The peer dropped the router flag.
  758                          * Remove the sender from the Default Router List and
  759                          * update the Destination Cache entries.
  760                          */
  761                         struct nd_defrouter *dr;
  762                         struct in6_addr *in6;
  763                         int s;
  764 
  765                         in6 = &((struct sockaddr_in6 *)rt_key(rt))->sin6_addr;
  766 
  767                         /*
  768                          * Lock to protect the default router list.
  769                          * XXX: this might be unnecessary, since this function
  770                          * is only called under the network software interrupt
  771                          * context.  However, we keep it just for safety.  
  772                          */
  773                         s = splnet();
  774                         dr = defrouter_lookup(in6, rt->rt_ifp);
  775                         if (dr)
  776                                 defrtrlist_del(dr);
  777                         else if (!ip6_forwarding && ip6_accept_rtadv) {
  778                                 /*
  779                                  * Even if the neighbor is not in the default
  780                                  * router list, the neighbor may be used
  781                                  * as a next hop for some destinations
  782                                  * (e.g. redirect case). So we must
  783                                  * call rt6_flush explicitly.
  784                                  */
  785                                 rt6_flush(&ip6->ip6_src, rt->rt_ifp);
  786                         }
  787                         splx(s);
  788                 }
  789                 ln->ln_router = is_router;
  790         }
  791         rt->rt_flags &= ~RTF_REJECT;
  792         ln->ln_asked = 0;
  793         if (ln->ln_hold) {
  794                 /*
  795                  * we assume ifp is not a loopback here, so just set the 2nd
  796                  * argument as the 1st one.
  797                  */
  798                 nd6_output(ifp, ifp, ln->ln_hold,
  799                            (struct sockaddr_in6 *)rt_key(rt), rt);
  800                 ln->ln_hold = 0;
  801         }
  802 
  803  freeit:
  804         m_freem(m);
  805         return;
  806 
  807  bad:
  808         icmp6stat.icp6s_badna++;
  809         m_freem(m);
  810 }
  811 
  812 /*
  813  * Neighbor advertisement output handling.
  814  *
  815  * Based on RFC 2461
  816  *
  817  * the following items are not implemented yet:
  818  * - proxy advertisement delay rule (RFC2461 7.2.8, last paragraph, SHOULD)
  819  * - anycast advertisement delay rule (RFC2461 7.2.7, SHOULD)
  820  */
  821 void
  822 nd6_na_output(ifp, daddr6, taddr6, flags, tlladdr, sdl0)
  823         struct ifnet *ifp;
  824         const struct in6_addr *daddr6, *taddr6;
  825         u_long flags;
  826         int tlladdr;            /* 1 if include target link-layer address */
  827         struct sockaddr *sdl0;  /* sockaddr_dl (= proxy NA) or NULL */
  828 {
  829         struct mbuf *m;
  830         struct ip6_hdr *ip6;
  831         struct nd_neighbor_advert *nd_na;
  832         struct in6_ifaddr *ia = NULL;
  833         struct ip6_moptions im6o;
  834         int icmp6len;
  835         int maxlen;
  836         caddr_t mac = NULL;
  837         struct ifnet *outif = NULL;
  838 
  839         /* estimate the size of message */
  840         maxlen = sizeof(*ip6) + sizeof(*nd_na);
  841         maxlen += (sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7;
  842         if (max_linkhdr + maxlen >= MCLBYTES) {
  843 #ifdef DIAGNOSTIC
  844                 printf("nd6_na_output: max_linkhdr + maxlen >= MCLBYTES "
  845                     "(%d + %d > %d)\n", max_linkhdr, maxlen, MCLBYTES);
  846 #endif
  847                 return;
  848         }
  849 
  850         MGETHDR(m, M_DONTWAIT, MT_DATA);
  851         if (m && max_linkhdr + maxlen >= MHLEN) {
  852                 MCLGET(m, M_DONTWAIT);
  853                 if ((m->m_flags & M_EXT) == 0) {
  854                         m_free(m);
  855                         m = NULL;
  856                 }
  857         }
  858         if (m == NULL)
  859                 return;
  860         m->m_pkthdr.rcvif = NULL;
  861 
  862         if (IN6_IS_ADDR_MULTICAST(daddr6)) {
  863                 m->m_flags |= M_MCAST;
  864                 im6o.im6o_multicast_ifp = ifp;
  865                 im6o.im6o_multicast_hlim = 255;
  866                 im6o.im6o_multicast_loop = 0;
  867         }
  868 
  869         icmp6len = sizeof(*nd_na);
  870         m->m_pkthdr.len = m->m_len = sizeof(struct ip6_hdr) + icmp6len;
  871         m->m_data += max_linkhdr;       /* or MH_ALIGN() equivalent? */
  872 
  873         /* fill neighbor advertisement packet */
  874         ip6 = mtod(m, struct ip6_hdr *);
  875         ip6->ip6_flow = 0;
  876         ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
  877         ip6->ip6_vfc |= IPV6_VERSION;
  878         ip6->ip6_nxt = IPPROTO_ICMPV6;
  879         ip6->ip6_hlim = 255;
  880         if (IN6_IS_ADDR_UNSPECIFIED(daddr6)) {
  881                 /* reply to DAD */
  882                 ip6->ip6_dst.s6_addr16[0] = IPV6_ADDR_INT16_MLL;
  883                 ip6->ip6_dst.s6_addr16[1] = htons(ifp->if_index);
  884                 ip6->ip6_dst.s6_addr32[1] = 0;
  885                 ip6->ip6_dst.s6_addr32[2] = 0;
  886                 ip6->ip6_dst.s6_addr32[3] = IPV6_ADDR_INT32_ONE;
  887                 flags &= ~ND_NA_FLAG_SOLICITED;
  888         } else
  889                 ip6->ip6_dst = *daddr6;
  890 
  891         /*
  892          * Select a source whose scope is the same as that of the dest.
  893          */
  894         ia = in6_ifawithifp(ifp, &ip6->ip6_dst);
  895         if (ia == NULL) {
  896                 m_freem(m);
  897                 return;
  898         }
  899         ip6->ip6_src = ia->ia_addr.sin6_addr;
  900         nd_na = (struct nd_neighbor_advert *)(ip6 + 1);
  901         nd_na->nd_na_type = ND_NEIGHBOR_ADVERT;
  902         nd_na->nd_na_code = 0;
  903         nd_na->nd_na_target = *taddr6;
  904         if (IN6_IS_SCOPE_LINKLOCAL(&nd_na->nd_na_target))
  905                 nd_na->nd_na_target.s6_addr16[1] = 0;
  906 
  907         /*
  908          * "tlladdr" indicates NS's condition for adding tlladdr or not.
  909          * see nd6_ns_input() for details.
  910          * Basically, if NS packet is sent to unicast/anycast addr,
  911          * target lladdr option SHOULD NOT be included.
  912          */
  913         if (tlladdr) {
  914                 /*
  915                  * sdl0 != NULL indicates proxy NA.  If we do proxy, use
  916                  * lladdr in sdl0.  If we are not proxying (sending NA for
  917                  * my address) use lladdr configured for the interface.
  918                  */
  919                 if (sdl0 == NULL)
  920                         mac = nd6_ifptomac(ifp);
  921                 else if (sdl0->sa_family == AF_LINK) {
  922                         struct sockaddr_dl *sdl;
  923                         sdl = (struct sockaddr_dl *)sdl0;
  924                         if (sdl->sdl_alen == ifp->if_addrlen)
  925                                 mac = LLADDR(sdl);
  926                 }
  927         }
  928         if (tlladdr && mac) {
  929                 int optlen = sizeof(struct nd_opt_hdr) + ifp->if_addrlen;
  930                 struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)(nd_na + 1);
  931                 
  932                 /* roundup to 8 bytes alignment! */
  933                 optlen = (optlen + 7) & ~7;
  934 
  935                 m->m_pkthdr.len += optlen;
  936                 m->m_len += optlen;
  937                 icmp6len += optlen;
  938                 bzero((caddr_t)nd_opt, optlen);
  939                 nd_opt->nd_opt_type = ND_OPT_TARGET_LINKADDR;
  940                 nd_opt->nd_opt_len = optlen >> 3;
  941                 bcopy(mac, (caddr_t)(nd_opt + 1), ifp->if_addrlen);
  942         } else
  943                 flags &= ~ND_NA_FLAG_OVERRIDE;
  944 
  945         ip6->ip6_plen = htons((u_short)icmp6len);
  946         nd_na->nd_na_flags_reserved = flags;
  947         nd_na->nd_na_cksum = 0;
  948         nd_na->nd_na_cksum =
  949                 in6_cksum(m, IPPROTO_ICMPV6, sizeof(struct ip6_hdr), icmp6len);
  950 
  951         ip6_output(m, NULL, NULL, 0, &im6o, &outif, NULL);
  952         if (outif) {
  953                 icmp6_ifstat_inc(outif, ifs6_out_msg);
  954                 icmp6_ifstat_inc(outif, ifs6_out_neighboradvert);
  955         }
  956         icmp6stat.icp6s_outhist[ND_NEIGHBOR_ADVERT]++;
  957 }
  958 
  959 caddr_t
  960 nd6_ifptomac(ifp)
  961         struct ifnet *ifp;
  962 {
  963         switch (ifp->if_type) {
  964         case IFT_ARCNET:
  965         case IFT_ETHER:
  966         case IFT_FDDI:
  967         case IFT_IEEE1394:
  968 #ifdef IFT_L2VLAN
  969         case IFT_L2VLAN:
  970 #endif
  971 #ifdef IFT_IEEE80211
  972         case IFT_IEEE80211:
  973 #endif
  974                 return ((caddr_t)(ifp + 1));
  975                 break;
  976         default:
  977                 return NULL;
  978         }
  979 }
  980 
  981 TAILQ_HEAD(dadq_head, dadq);
  982 struct dadq {
  983         TAILQ_ENTRY(dadq) dad_list;
  984         struct ifaddr *dad_ifa;
  985         int dad_count;          /* max NS to send */
  986         int dad_ns_tcount;      /* # of trials to send NS */
  987         int dad_ns_ocount;      /* NS sent so far */
  988         int dad_ns_icount;
  989         int dad_na_icount;
  990         struct callout dad_timer_ch;
  991 };
  992 
  993 static struct dadq_head dadq;
  994 static int dad_init = 0;
  995 
  996 static struct dadq *
  997 nd6_dad_find(ifa)
  998         struct ifaddr *ifa;
  999 {
 1000         struct dadq *dp;
 1001 
 1002         for (dp = dadq.tqh_first; dp; dp = dp->dad_list.tqe_next) {
 1003                 if (dp->dad_ifa == ifa)
 1004                         return dp;
 1005         }
 1006         return NULL;
 1007 }
 1008 
 1009 static void
 1010 nd6_dad_starttimer(dp, ticks)
 1011         struct dadq *dp;
 1012         int ticks;
 1013 {
 1014 
 1015         callout_reset(&dp->dad_timer_ch, ticks,
 1016             (void (*) __P((void *)))nd6_dad_timer, (void *)dp->dad_ifa);
 1017 }
 1018 
 1019 static void
 1020 nd6_dad_stoptimer(dp)
 1021         struct dadq *dp;
 1022 {
 1023 
 1024         callout_stop(&dp->dad_timer_ch);
 1025 }
 1026 
 1027 /*
 1028  * Start Duplicated Address Detection (DAD) for specified interface address.
 1029  */
 1030 void
 1031 nd6_dad_start(ifa, tick)
 1032         struct ifaddr *ifa;
 1033         int *tick;      /* minimum delay ticks for IFF_UP event */
 1034 {
 1035         struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
 1036         struct dadq *dp;
 1037 
 1038         if (!dad_init) {
 1039                 TAILQ_INIT(&dadq);
 1040                 dad_init++;
 1041         }
 1042 
 1043         /*
 1044          * If we don't need DAD, don't do it.
 1045          * There are several cases:
 1046          * - DAD is disabled (ip6_dad_count == 0)
 1047          * - the interface address is anycast
 1048          */
 1049         if (!(ia->ia6_flags & IN6_IFF_TENTATIVE)) {
 1050                 log(LOG_DEBUG,
 1051                         "nd6_dad_start: called with non-tentative address "
 1052                         "%s(%s)\n",
 1053                         ip6_sprintf(&ia->ia_addr.sin6_addr),
 1054                         ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
 1055                 return;
 1056         }
 1057         if (ia->ia6_flags & IN6_IFF_ANYCAST) {
 1058                 ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
 1059                 return;
 1060         }
 1061         if (!ip6_dad_count) {
 1062                 ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
 1063                 return;
 1064         }
 1065         if (!ifa->ifa_ifp)
 1066                 panic("nd6_dad_start: ifa->ifa_ifp == NULL");
 1067         if (!(ifa->ifa_ifp->if_flags & IFF_UP))
 1068                 return;
 1069         if (nd6_dad_find(ifa) != NULL) {
 1070                 /* DAD already in progress */
 1071                 return;
 1072         }
 1073 
 1074         dp = malloc(sizeof(*dp), M_IP6NDP, M_NOWAIT);
 1075         if (dp == NULL) {
 1076                 log(LOG_ERR, "nd6_dad_start: memory allocation failed for "
 1077                         "%s(%s)\n",
 1078                         ip6_sprintf(&ia->ia_addr.sin6_addr),
 1079                         ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
 1080                 return;
 1081         }
 1082         bzero(dp, sizeof(*dp));
 1083         callout_init(&dp->dad_timer_ch, 0);
 1084         TAILQ_INSERT_TAIL(&dadq, (struct dadq *)dp, dad_list);
 1085 
 1086         nd6log((LOG_DEBUG, "%s: starting DAD for %s\n", if_name(ifa->ifa_ifp),
 1087             ip6_sprintf(&ia->ia_addr.sin6_addr)));
 1088 
 1089         /*
 1090          * Send NS packet for DAD, ip6_dad_count times.
 1091          * Note that we must delay the first transmission, if this is the
 1092          * first packet to be sent from the interface after interface
 1093          * (re)initialization.
 1094          */
 1095         dp->dad_ifa = ifa;
 1096         IFAREF(ifa);    /* just for safety */
 1097         dp->dad_count = ip6_dad_count;
 1098         dp->dad_ns_icount = dp->dad_na_icount = 0;
 1099         dp->dad_ns_ocount = dp->dad_ns_tcount = 0;
 1100         if (tick == NULL) {
 1101                 nd6_dad_ns_output(dp, ifa);
 1102                 nd6_dad_starttimer(dp, 
 1103                     nd_ifinfo[ifa->ifa_ifp->if_index].retrans * hz / 1000);
 1104         } else {
 1105                 int ntick;
 1106 
 1107                 if (*tick == 0)
 1108                         ntick = random() % (MAX_RTR_SOLICITATION_DELAY * hz);
 1109                 else
 1110                         ntick = *tick + random() % (hz / 2);
 1111                 *tick = ntick;
 1112                 nd6_dad_starttimer(dp, ntick);
 1113         }
 1114 }
 1115 
 1116 /*
 1117  * terminate DAD unconditionally.  used for address removals.
 1118  */
 1119 void
 1120 nd6_dad_stop(ifa)
 1121         struct ifaddr *ifa;
 1122 {
 1123         struct dadq *dp;
 1124 
 1125         if (!dad_init)
 1126                 return;
 1127         dp = nd6_dad_find(ifa);
 1128         if (!dp) {
 1129                 /* DAD wasn't started yet */
 1130                 return;
 1131         }
 1132 
 1133         nd6_dad_stoptimer(dp);
 1134 
 1135         TAILQ_REMOVE(&dadq, (struct dadq *)dp, dad_list);
 1136         free(dp, M_IP6NDP);
 1137         dp = NULL;
 1138         IFAFREE(ifa);
 1139 }
 1140 
 1141 static void
 1142 nd6_dad_timer(ifa)
 1143         struct ifaddr *ifa;
 1144 {
 1145         int s;
 1146         struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
 1147         struct dadq *dp;
 1148 
 1149         s = splnet();           /* XXX */
 1150 
 1151         /* Sanity check */
 1152         if (ia == NULL) {
 1153                 log(LOG_ERR, "nd6_dad_timer: called with null parameter\n");
 1154                 goto done;
 1155         }
 1156         dp = nd6_dad_find(ifa);
 1157         if (dp == NULL) {
 1158                 log(LOG_ERR, "nd6_dad_timer: DAD structure not found\n");
 1159                 goto done;
 1160         }
 1161         if (ia->ia6_flags & IN6_IFF_DUPLICATED) {
 1162                 log(LOG_ERR, "nd6_dad_timer: called with duplicated address "
 1163                         "%s(%s)\n",
 1164                         ip6_sprintf(&ia->ia_addr.sin6_addr),
 1165                         ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
 1166                 goto done;
 1167         }
 1168         if ((ia->ia6_flags & IN6_IFF_TENTATIVE) == 0) {
 1169                 log(LOG_ERR, "nd6_dad_timer: called with non-tentative address "
 1170                         "%s(%s)\n",
 1171                         ip6_sprintf(&ia->ia_addr.sin6_addr),
 1172                         ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
 1173                 goto done;
 1174         }
 1175 
 1176         /* timeouted with IFF_{RUNNING,UP} check */
 1177         if (dp->dad_ns_tcount > dad_maxtry) {
 1178                 nd6log((LOG_INFO, "%s: could not run DAD, driver problem?\n",
 1179                         if_name(ifa->ifa_ifp)));
 1180 
 1181                 TAILQ_REMOVE(&dadq, (struct dadq *)dp, dad_list);
 1182                 free(dp, M_IP6NDP);
 1183                 dp = NULL;
 1184                 IFAFREE(ifa);
 1185                 goto done;
 1186         }
 1187 
 1188         /* Need more checks? */
 1189         if (dp->dad_ns_ocount < dp->dad_count) {
 1190                 /*
 1191                  * We have more NS to go.  Send NS packet for DAD.
 1192                  */
 1193                 nd6_dad_ns_output(dp, ifa);
 1194                 nd6_dad_starttimer(dp, 
 1195                     nd_ifinfo[ifa->ifa_ifp->if_index].retrans * hz / 1000);
 1196         } else {
 1197                 /*
 1198                  * We have transmitted sufficient number of DAD packets.
 1199                  * See what we've got.
 1200                  */
 1201                 int duplicate;
 1202 
 1203                 duplicate = 0;
 1204 
 1205                 if (dp->dad_na_icount) {
 1206                         /*
 1207                          * the check is in nd6_dad_na_input(),
 1208                          * but just in case
 1209                          */
 1210                         duplicate++;
 1211                 }
 1212 
 1213                 if (dp->dad_ns_icount) {
 1214 #if 0 /* heuristics */
 1215                         /*
 1216                          * if
 1217                          * - we have sent many(?) DAD NS, and
 1218                          * - the number of NS we sent equals to the
 1219                          *   number of NS we've got, and
 1220                          * - we've got no NA
 1221                          * we may have a faulty network card/driver which
 1222                          * loops back multicasts to myself.
 1223                          */
 1224                         if (3 < dp->dad_count
 1225                          && dp->dad_ns_icount == dp->dad_count
 1226                          && dp->dad_na_icount == 0) {
 1227                                 log(LOG_INFO, "DAD questionable for %s(%s): "
 1228                                         "network card loops back multicast?\n",
 1229                                         ip6_sprintf(&ia->ia_addr.sin6_addr),
 1230                                         if_name(ifa->ifa_ifp));
 1231                                 /* XXX consider it a duplicate or not? */
 1232                                 /* duplicate++; */
 1233                         } else {
 1234                                 /* We've seen NS, means DAD has failed. */
 1235                                 duplicate++;
 1236                         }
 1237 #else
 1238                         /* We've seen NS, means DAD has failed. */
 1239                         duplicate++;
 1240 #endif
 1241                 }
 1242 
 1243                 if (duplicate) {
 1244                         /* (*dp) will be freed in nd6_dad_duplicated() */
 1245                         dp = NULL;
 1246                         nd6_dad_duplicated(ifa);
 1247                 } else {
 1248                         /*
 1249                          * We are done with DAD.  No NA came, no NS came.
 1250                          * duplicated address found.
 1251                          */
 1252                         ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
 1253 
 1254                         nd6log((LOG_DEBUG,
 1255                             "%s: DAD complete for %s - no duplicates found\n",
 1256                             if_name(ifa->ifa_ifp),
 1257                             ip6_sprintf(&ia->ia_addr.sin6_addr)));
 1258 
 1259                         TAILQ_REMOVE(&dadq, (struct dadq *)dp, dad_list);
 1260                         free(dp, M_IP6NDP);
 1261                         dp = NULL;
 1262                         IFAFREE(ifa);
 1263                 }
 1264         }
 1265 
 1266 done:
 1267         splx(s);
 1268 }
 1269 
 1270 void
 1271 nd6_dad_duplicated(ifa)
 1272         struct ifaddr *ifa;
 1273 {
 1274         struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
 1275         struct dadq *dp;
 1276 
 1277         dp = nd6_dad_find(ifa);
 1278         if (dp == NULL) {
 1279                 log(LOG_ERR, "nd6_dad_duplicated: DAD structure not found\n");
 1280                 return;
 1281         }
 1282 
 1283         log(LOG_ERR, "%s: DAD detected duplicate IPv6 address %s: "
 1284             "NS in/out=%d/%d, NA in=%d\n",
 1285             if_name(ifa->ifa_ifp), ip6_sprintf(&ia->ia_addr.sin6_addr),
 1286             dp->dad_ns_icount, dp->dad_ns_ocount, dp->dad_na_icount);
 1287 
 1288         ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
 1289         ia->ia6_flags |= IN6_IFF_DUPLICATED;
 1290 
 1291         /* We are done with DAD, with duplicated address found. (failure) */
 1292         nd6_dad_stoptimer(dp);
 1293 
 1294         log(LOG_ERR, "%s: DAD complete for %s - duplicate found\n",
 1295             if_name(ifa->ifa_ifp), ip6_sprintf(&ia->ia_addr.sin6_addr));
 1296         log(LOG_ERR, "%s: manual intervention required\n",
 1297             if_name(ifa->ifa_ifp));
 1298 
 1299         TAILQ_REMOVE(&dadq, (struct dadq *)dp, dad_list);
 1300         free(dp, M_IP6NDP);
 1301         dp = NULL;
 1302         IFAFREE(ifa);
 1303 }
 1304 
 1305 static void
 1306 nd6_dad_ns_output(dp, ifa)
 1307         struct dadq *dp;
 1308         struct ifaddr *ifa;
 1309 {
 1310         struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
 1311         struct ifnet *ifp = ifa->ifa_ifp;
 1312 
 1313         dp->dad_ns_tcount++;
 1314         if ((ifp->if_flags & IFF_UP) == 0) {
 1315 #if 0
 1316                 printf("%s: interface down?\n", if_name(ifp));
 1317 #endif
 1318                 return;
 1319         }
 1320         if ((ifp->if_flags & IFF_RUNNING) == 0) {
 1321 #if 0
 1322                 printf("%s: interface not running?\n", if_name(ifp));
 1323 #endif
 1324                 return;
 1325         }
 1326 
 1327         dp->dad_ns_ocount++;
 1328         nd6_ns_output(ifp, NULL, &ia->ia_addr.sin6_addr, NULL, 1);
 1329 }
 1330 
 1331 static void
 1332 nd6_dad_ns_input(ifa)
 1333         struct ifaddr *ifa;
 1334 {
 1335         struct in6_ifaddr *ia;
 1336         struct ifnet *ifp;
 1337         const struct in6_addr *taddr6;
 1338         struct dadq *dp;
 1339         int duplicate;
 1340 
 1341         if (!ifa)
 1342                 panic("ifa == NULL in nd6_dad_ns_input");
 1343 
 1344         ia = (struct in6_ifaddr *)ifa;
 1345         ifp = ifa->ifa_ifp;
 1346         taddr6 = &ia->ia_addr.sin6_addr;
 1347         duplicate = 0;
 1348         dp = nd6_dad_find(ifa);
 1349 
 1350         /* Quickhack - completely ignore DAD NS packets */
 1351         if (dad_ignore_ns) {
 1352                 nd6log((LOG_INFO,
 1353                     "nd6_dad_ns_input: ignoring DAD NS packet for "
 1354                     "address %s(%s)\n", ip6_sprintf(taddr6),
 1355                     if_name(ifa->ifa_ifp)));
 1356                 return;
 1357         }
 1358 
 1359         /*
 1360          * if I'm yet to start DAD, someone else started using this address
 1361          * first.  I have a duplicate and you win.
 1362          */
 1363         if (!dp || dp->dad_ns_ocount == 0)
 1364                 duplicate++;
 1365 
 1366         /* XXX more checks for loopback situation - see nd6_dad_timer too */
 1367 
 1368         if (duplicate) {
 1369                 dp = NULL;      /* will be freed in nd6_dad_duplicated() */
 1370                 nd6_dad_duplicated(ifa);
 1371         } else {
 1372                 /*
 1373                  * not sure if I got a duplicate.
 1374                  * increment ns count and see what happens.
 1375                  */
 1376                 if (dp)
 1377                         dp->dad_ns_icount++;
 1378         }
 1379 }
 1380 
 1381 static void
 1382 nd6_dad_na_input(ifa)
 1383         struct ifaddr *ifa;
 1384 {
 1385         struct dadq *dp;
 1386 
 1387         if (!ifa)
 1388                 panic("ifa == NULL in nd6_dad_na_input");
 1389 
 1390         dp = nd6_dad_find(ifa);
 1391         if (dp)
 1392                 dp->dad_na_icount++;
 1393 
 1394         /* remove the address. */
 1395         nd6_dad_duplicated(ifa);
 1396 }

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