The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/netinet6/nd6_nbr.c

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    1 /*-
    2  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
    3  * All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer.
   10  * 2. Redistributions in binary form must reproduce the above copyright
   11  *    notice, this list of conditions and the following disclaimer in the
   12  *    documentation and/or other materials provided with the distribution.
   13  * 3. Neither the name of the project nor the names of its contributors
   14  *    may be used to endorse or promote products derived from this software
   15  *    without specific prior written permission.
   16  *
   17  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
   18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
   21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   27  * SUCH DAMAGE.
   28  *
   29  *      $KAME: nd6_nbr.c,v 1.86 2002/01/21 02:33:04 jinmei Exp $
   30  */
   31 
   32 #include <sys/cdefs.h>
   33 __FBSDID("$FreeBSD: releng/10.0/sys/netinet6/nd6_nbr.c 248328 2013-03-15 13:48:53Z glebius $");
   34 
   35 #include "opt_inet.h"
   36 #include "opt_inet6.h"
   37 #include "opt_ipsec.h"
   38 #include "opt_mpath.h"
   39 
   40 #include <sys/param.h>
   41 #include <sys/systm.h>
   42 #include <sys/malloc.h>
   43 #include <sys/lock.h>
   44 #include <sys/rwlock.h>
   45 #include <sys/mbuf.h>
   46 #include <sys/socket.h>
   47 #include <sys/sockio.h>
   48 #include <sys/time.h>
   49 #include <sys/kernel.h>
   50 #include <sys/errno.h>
   51 #include <sys/syslog.h>
   52 #include <sys/queue.h>
   53 #include <sys/callout.h>
   54 
   55 #include <net/if.h>
   56 #include <net/if_types.h>
   57 #include <net/if_dl.h>
   58 #include <net/if_var.h>
   59 #include <net/route.h>
   60 #ifdef RADIX_MPATH
   61 #include <net/radix_mpath.h>
   62 #endif
   63 
   64 #include <netinet/in.h>
   65 #include <netinet/in_var.h>
   66 #include <net/if_llatbl.h>
   67 #define L3_ADDR_SIN6(le)        ((struct sockaddr_in6 *) L3_ADDR(le))
   68 #include <netinet6/in6_var.h>
   69 #include <netinet6/in6_ifattach.h>
   70 #include <netinet/ip6.h>
   71 #include <netinet6/ip6_var.h>
   72 #include <netinet6/scope6_var.h>
   73 #include <netinet6/nd6.h>
   74 #include <netinet/icmp6.h>
   75 #include <netinet/ip_carp.h>
   76 #include <netinet6/send.h>
   77 
   78 #define SDL(s) ((struct sockaddr_dl *)s)
   79 
   80 struct dadq;
   81 static struct dadq *nd6_dad_find(struct ifaddr *);
   82 static void nd6_dad_starttimer(struct dadq *, int);
   83 static void nd6_dad_stoptimer(struct dadq *);
   84 static void nd6_dad_timer(struct dadq *);
   85 static void nd6_dad_ns_output(struct dadq *, struct ifaddr *);
   86 static void nd6_dad_ns_input(struct ifaddr *);
   87 static void nd6_dad_na_input(struct ifaddr *);
   88 static void nd6_na_output_fib(struct ifnet *, const struct in6_addr *,
   89     const struct in6_addr *, u_long, int, struct sockaddr *, u_int);
   90 
   91 VNET_DEFINE(int, dad_ignore_ns) = 0;    /* ignore NS in DAD - specwise incorrect*/
   92 VNET_DEFINE(int, dad_maxtry) = 15;      /* max # of *tries* to transmit DAD packet */
   93 #define V_dad_ignore_ns                 VNET(dad_ignore_ns)
   94 #define V_dad_maxtry                    VNET(dad_maxtry)
   95 
   96 /*
   97  * Input a Neighbor Solicitation Message.
   98  *
   99  * Based on RFC 2461
  100  * Based on RFC 2462 (duplicate address detection)
  101  */
  102 void
  103 nd6_ns_input(struct mbuf *m, int off, int icmp6len)
  104 {
  105         struct ifnet *ifp = m->m_pkthdr.rcvif;
  106         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
  107         struct nd_neighbor_solicit *nd_ns;
  108         struct in6_addr saddr6 = ip6->ip6_src;
  109         struct in6_addr daddr6 = ip6->ip6_dst;
  110         struct in6_addr taddr6;
  111         struct in6_addr myaddr6;
  112         char *lladdr = NULL;
  113         struct ifaddr *ifa = NULL;
  114         int lladdrlen = 0;
  115         int anycast = 0, proxy = 0, tentative = 0;
  116         int tlladdr;
  117         int rflag;
  118         union nd_opts ndopts;
  119         struct sockaddr_dl proxydl;
  120         char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
  121 
  122         rflag = (V_ip6_forwarding) ? ND_NA_FLAG_ROUTER : 0;
  123         if (ND_IFINFO(ifp)->flags & ND6_IFF_ACCEPT_RTADV && V_ip6_norbit_raif)
  124                 rflag = 0;
  125 #ifndef PULLDOWN_TEST
  126         IP6_EXTHDR_CHECK(m, off, icmp6len,);
  127         nd_ns = (struct nd_neighbor_solicit *)((caddr_t)ip6 + off);
  128 #else
  129         IP6_EXTHDR_GET(nd_ns, struct nd_neighbor_solicit *, m, off, icmp6len);
  130         if (nd_ns == NULL) {
  131                 ICMP6STAT_INC(icp6s_tooshort);
  132                 return;
  133         }
  134 #endif
  135         ip6 = mtod(m, struct ip6_hdr *); /* adjust pointer for safety */
  136         taddr6 = nd_ns->nd_ns_target;
  137         if (in6_setscope(&taddr6, ifp, NULL) != 0)
  138                 goto bad;
  139 
  140         if (ip6->ip6_hlim != 255) {
  141                 nd6log((LOG_ERR,
  142                     "nd6_ns_input: invalid hlim (%d) from %s to %s on %s\n",
  143                     ip6->ip6_hlim, ip6_sprintf(ip6bufs, &ip6->ip6_src),
  144                     ip6_sprintf(ip6bufd, &ip6->ip6_dst), if_name(ifp)));
  145                 goto bad;
  146         }
  147 
  148         if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) {
  149                 /* dst has to be a solicited node multicast address. */
  150                 if (daddr6.s6_addr16[0] == IPV6_ADDR_INT16_MLL &&
  151                     /* don't check ifindex portion */
  152                     daddr6.s6_addr32[1] == 0 &&
  153                     daddr6.s6_addr32[2] == IPV6_ADDR_INT32_ONE &&
  154                     daddr6.s6_addr8[12] == 0xff) {
  155                         ; /* good */
  156                 } else {
  157                         nd6log((LOG_INFO, "nd6_ns_input: bad DAD packet "
  158                             "(wrong ip6 dst)\n"));
  159                         goto bad;
  160                 }
  161         } else if (!V_nd6_onlink_ns_rfc4861) {
  162                 struct sockaddr_in6 src_sa6;
  163 
  164                 /*
  165                  * According to recent IETF discussions, it is not a good idea
  166                  * to accept a NS from an address which would not be deemed
  167                  * to be a neighbor otherwise.  This point is expected to be
  168                  * clarified in future revisions of the specification.
  169                  */
  170                 bzero(&src_sa6, sizeof(src_sa6));
  171                 src_sa6.sin6_family = AF_INET6;
  172                 src_sa6.sin6_len = sizeof(src_sa6);
  173                 src_sa6.sin6_addr = saddr6;
  174                 if (nd6_is_addr_neighbor(&src_sa6, ifp) == 0) {
  175                         nd6log((LOG_INFO, "nd6_ns_input: "
  176                                 "NS packet from non-neighbor\n"));
  177                         goto bad;
  178                 }
  179         }
  180 
  181         if (IN6_IS_ADDR_MULTICAST(&taddr6)) {
  182                 nd6log((LOG_INFO, "nd6_ns_input: bad NS target (multicast)\n"));
  183                 goto bad;
  184         }
  185 
  186         icmp6len -= sizeof(*nd_ns);
  187         nd6_option_init(nd_ns + 1, icmp6len, &ndopts);
  188         if (nd6_options(&ndopts) < 0) {
  189                 nd6log((LOG_INFO,
  190                     "nd6_ns_input: invalid ND option, ignored\n"));
  191                 /* nd6_options have incremented stats */
  192                 goto freeit;
  193         }
  194 
  195         if (ndopts.nd_opts_src_lladdr) {
  196                 lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1);
  197                 lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
  198         }
  199 
  200         if (IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src) && lladdr) {
  201                 nd6log((LOG_INFO, "nd6_ns_input: bad DAD packet "
  202                     "(link-layer address option)\n"));
  203                 goto bad;
  204         }
  205 
  206         /*
  207          * Attaching target link-layer address to the NA?
  208          * (RFC 2461 7.2.4)
  209          *
  210          * NS IP dst is unicast/anycast                 MUST NOT add
  211          * NS IP dst is solicited-node multicast        MUST add
  212          *
  213          * In implementation, we add target link-layer address by default.
  214          * We do not add one in MUST NOT cases.
  215          */
  216         if (!IN6_IS_ADDR_MULTICAST(&daddr6))
  217                 tlladdr = 0;
  218         else
  219                 tlladdr = 1;
  220 
  221         /*
  222          * Target address (taddr6) must be either:
  223          * (1) Valid unicast/anycast address for my receiving interface,
  224          * (2) Unicast address for which I'm offering proxy service, or
  225          * (3) "tentative" address on which DAD is being performed.
  226          */
  227         /* (1) and (3) check. */
  228         if (ifp->if_carp)
  229                 ifa = (*carp_iamatch6_p)(ifp, &taddr6);
  230         else
  231                 ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
  232 
  233         /* (2) check. */
  234         if (ifa == NULL) {
  235                 struct rtentry *rt;
  236                 struct sockaddr_in6 tsin6;
  237                 int need_proxy;
  238 #ifdef RADIX_MPATH
  239                 struct route_in6 ro;
  240 #endif
  241 
  242                 bzero(&tsin6, sizeof tsin6);
  243                 tsin6.sin6_len = sizeof(struct sockaddr_in6);
  244                 tsin6.sin6_family = AF_INET6;
  245                 tsin6.sin6_addr = taddr6;
  246 
  247                 /* Always use the default FIB. */
  248 #ifdef RADIX_MPATH
  249                 bzero(&ro, sizeof(ro));
  250                 ro.ro_dst = tsin6;
  251                 rtalloc_mpath_fib((struct route *)&ro, RTF_ANNOUNCE,
  252                     RT_DEFAULT_FIB);
  253                 rt = ro.ro_rt;
  254 #else
  255                 rt = in6_rtalloc1((struct sockaddr *)&tsin6, 0, 0,
  256                     RT_DEFAULT_FIB);
  257 #endif
  258                 need_proxy = (rt && (rt->rt_flags & RTF_ANNOUNCE) != 0 &&
  259                     rt->rt_gateway->sa_family == AF_LINK);
  260                 if (rt != NULL) {
  261                         /*
  262                          * Make a copy while we can be sure that rt_gateway
  263                          * is still stable before unlocking to avoid lock
  264                          * order problems.  proxydl will only be used if
  265                          * proxy will be set in the next block.
  266                          */
  267                         if (need_proxy)
  268                                 proxydl = *SDL(rt->rt_gateway);
  269                         RTFREE_LOCKED(rt);
  270                 }
  271                 if (need_proxy) {
  272                         /*
  273                          * proxy NDP for single entry
  274                          */
  275                         ifa = (struct ifaddr *)in6ifa_ifpforlinklocal(ifp,
  276                                 IN6_IFF_NOTREADY|IN6_IFF_ANYCAST);
  277                         if (ifa)
  278                                 proxy = 1;
  279                 }
  280         }
  281         if (ifa == NULL) {
  282                 /*
  283                  * We've got an NS packet, and we don't have that adddress
  284                  * assigned for us.  We MUST silently ignore it.
  285                  * See RFC2461 7.2.3.
  286                  */
  287                 goto freeit;
  288         }
  289         myaddr6 = *IFA_IN6(ifa);
  290         anycast = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_ANYCAST;
  291         tentative = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_TENTATIVE;
  292         if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_DUPLICATED)
  293                 goto freeit;
  294 
  295         if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
  296                 nd6log((LOG_INFO, "nd6_ns_input: lladdrlen mismatch for %s "
  297                     "(if %d, NS packet %d)\n",
  298                     ip6_sprintf(ip6bufs, &taddr6),
  299                     ifp->if_addrlen, lladdrlen - 2));
  300                 goto bad;
  301         }
  302 
  303         if (IN6_ARE_ADDR_EQUAL(&myaddr6, &saddr6)) {
  304                 nd6log((LOG_INFO, "nd6_ns_input: duplicate IP6 address %s\n",
  305                     ip6_sprintf(ip6bufs, &saddr6)));
  306                 goto freeit;
  307         }
  308 
  309         /*
  310          * We have neighbor solicitation packet, with target address equals to
  311          * one of my tentative address.
  312          *
  313          * src addr     how to process?
  314          * ---          ---
  315          * multicast    of course, invalid (rejected in ip6_input)
  316          * unicast      somebody is doing address resolution -> ignore
  317          * unspec       dup address detection
  318          *
  319          * The processing is defined in RFC 2462.
  320          */
  321         if (tentative) {
  322                 /*
  323                  * If source address is unspecified address, it is for
  324                  * duplicate address detection.
  325                  *
  326                  * If not, the packet is for addess resolution;
  327                  * silently ignore it.
  328                  */
  329                 if (IN6_IS_ADDR_UNSPECIFIED(&saddr6))
  330                         nd6_dad_ns_input(ifa);
  331 
  332                 goto freeit;
  333         }
  334 
  335         /*
  336          * If the source address is unspecified address, entries must not
  337          * be created or updated.
  338          * It looks that sender is performing DAD.  Output NA toward
  339          * all-node multicast address, to tell the sender that I'm using
  340          * the address.
  341          * S bit ("solicited") must be zero.
  342          */
  343         if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) {
  344                 struct in6_addr in6_all;
  345 
  346                 in6_all = in6addr_linklocal_allnodes;
  347                 if (in6_setscope(&in6_all, ifp, NULL) != 0)
  348                         goto bad;
  349                 nd6_na_output_fib(ifp, &in6_all, &taddr6,
  350                     ((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE) |
  351                     rflag, tlladdr, proxy ? (struct sockaddr *)&proxydl : NULL,
  352                     M_GETFIB(m));
  353                 goto freeit;
  354         }
  355 
  356         nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen,
  357             ND_NEIGHBOR_SOLICIT, 0);
  358 
  359         nd6_na_output_fib(ifp, &saddr6, &taddr6,
  360             ((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE) |
  361             rflag | ND_NA_FLAG_SOLICITED, tlladdr,
  362             proxy ? (struct sockaddr *)&proxydl : NULL, M_GETFIB(m));
  363  freeit:
  364         if (ifa != NULL)
  365                 ifa_free(ifa);
  366         m_freem(m);
  367         return;
  368 
  369  bad:
  370         nd6log((LOG_ERR, "nd6_ns_input: src=%s\n",
  371                 ip6_sprintf(ip6bufs, &saddr6)));
  372         nd6log((LOG_ERR, "nd6_ns_input: dst=%s\n",
  373                 ip6_sprintf(ip6bufs, &daddr6)));
  374         nd6log((LOG_ERR, "nd6_ns_input: tgt=%s\n",
  375                 ip6_sprintf(ip6bufs, &taddr6)));
  376         ICMP6STAT_INC(icp6s_badns);
  377         if (ifa != NULL)
  378                 ifa_free(ifa);
  379         m_freem(m);
  380 }
  381 
  382 /*
  383  * Output a Neighbor Solicitation Message. Caller specifies:
  384  *      - ICMP6 header source IP6 address
  385  *      - ND6 header target IP6 address
  386  *      - ND6 header source datalink address
  387  *
  388  * Based on RFC 2461
  389  * Based on RFC 2462 (duplicate address detection)
  390  *
  391  *   ln - for source address determination
  392  *  dad - duplicate address detection
  393  */
  394 void
  395 nd6_ns_output(struct ifnet *ifp, const struct in6_addr *daddr6, 
  396     const struct in6_addr *taddr6, struct llentry *ln, int dad)
  397 {
  398         struct mbuf *m;
  399         struct m_tag *mtag;
  400         struct ip6_hdr *ip6;
  401         struct nd_neighbor_solicit *nd_ns;
  402         struct ip6_moptions im6o;
  403         int icmp6len;
  404         int maxlen;
  405         caddr_t mac;
  406         struct route_in6 ro;
  407 
  408         if (IN6_IS_ADDR_MULTICAST(taddr6))
  409                 return;
  410 
  411         /* estimate the size of message */
  412         maxlen = sizeof(*ip6) + sizeof(*nd_ns);
  413         maxlen += (sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7;
  414         if (max_linkhdr + maxlen >= MCLBYTES) {
  415 #ifdef DIAGNOSTIC
  416                 printf("nd6_ns_output: max_linkhdr + maxlen >= MCLBYTES "
  417                     "(%d + %d > %d)\n", max_linkhdr, maxlen, MCLBYTES);
  418 #endif
  419                 return;
  420         }
  421 
  422         if (max_linkhdr + maxlen > MHLEN)
  423                 m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
  424         else
  425                 m = m_gethdr(M_NOWAIT, MT_DATA);
  426         if (m == NULL)
  427                 return;
  428 
  429         bzero(&ro, sizeof(ro));
  430 
  431         if (daddr6 == NULL || IN6_IS_ADDR_MULTICAST(daddr6)) {
  432                 m->m_flags |= M_MCAST;
  433                 im6o.im6o_multicast_ifp = ifp;
  434                 im6o.im6o_multicast_hlim = 255;
  435                 im6o.im6o_multicast_loop = 0;
  436         }
  437 
  438         icmp6len = sizeof(*nd_ns);
  439         m->m_pkthdr.len = m->m_len = sizeof(*ip6) + icmp6len;
  440         m->m_data += max_linkhdr;       /* or MH_ALIGN() equivalent? */
  441 
  442         /* fill neighbor solicitation packet */
  443         ip6 = mtod(m, struct ip6_hdr *);
  444         ip6->ip6_flow = 0;
  445         ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
  446         ip6->ip6_vfc |= IPV6_VERSION;
  447         /* ip6->ip6_plen will be set later */
  448         ip6->ip6_nxt = IPPROTO_ICMPV6;
  449         ip6->ip6_hlim = 255;
  450         if (daddr6)
  451                 ip6->ip6_dst = *daddr6;
  452         else {
  453                 ip6->ip6_dst.s6_addr16[0] = IPV6_ADDR_INT16_MLL;
  454                 ip6->ip6_dst.s6_addr16[1] = 0;
  455                 ip6->ip6_dst.s6_addr32[1] = 0;
  456                 ip6->ip6_dst.s6_addr32[2] = IPV6_ADDR_INT32_ONE;
  457                 ip6->ip6_dst.s6_addr32[3] = taddr6->s6_addr32[3];
  458                 ip6->ip6_dst.s6_addr8[12] = 0xff;
  459                 if (in6_setscope(&ip6->ip6_dst, ifp, NULL) != 0)
  460                         goto bad;
  461         }
  462         if (!dad) {
  463                 struct ifaddr *ifa;
  464 
  465                 /*
  466                  * RFC2461 7.2.2:
  467                  * "If the source address of the packet prompting the
  468                  * solicitation is the same as one of the addresses assigned
  469                  * to the outgoing interface, that address SHOULD be placed
  470                  * in the IP Source Address of the outgoing solicitation.
  471                  * Otherwise, any one of the addresses assigned to the
  472                  * interface should be used."
  473                  *
  474                  * We use the source address for the prompting packet
  475                  * (saddr6), if:
  476                  * - saddr6 is given from the caller (by giving "ln"), and
  477                  * - saddr6 belongs to the outgoing interface.
  478                  * Otherwise, we perform the source address selection as usual.
  479                  */
  480                 struct in6_addr *hsrc;
  481 
  482                 hsrc = NULL;
  483                 if (ln != NULL) {
  484                         LLE_RLOCK(ln);
  485                         if (ln->la_hold != NULL) {
  486                                 struct ip6_hdr *hip6;           /* hold ip6 */
  487 
  488                                 /*
  489                                  * assuming every packet in la_hold has the same IP
  490                                  * header
  491                                  */
  492                                 hip6 = mtod(ln->la_hold, struct ip6_hdr *);
  493                                 /* XXX pullup? */
  494                                 if (sizeof(*hip6) < ln->la_hold->m_len) {
  495                                         ip6->ip6_src = hip6->ip6_src;
  496                                         hsrc = &hip6->ip6_src;
  497                                 }
  498                         }
  499                         LLE_RUNLOCK(ln);
  500                 }
  501                 if (hsrc && (ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp,
  502                     hsrc)) != NULL) {
  503                         /* ip6_src set already. */
  504                         ifa_free(ifa);
  505                 } else {
  506                         int error;
  507                         struct sockaddr_in6 dst_sa;
  508                         struct in6_addr src_in;
  509                         struct ifnet *oifp;
  510 
  511                         bzero(&dst_sa, sizeof(dst_sa));
  512                         dst_sa.sin6_family = AF_INET6;
  513                         dst_sa.sin6_len = sizeof(dst_sa);
  514                         dst_sa.sin6_addr = ip6->ip6_dst;
  515 
  516                         oifp = ifp;
  517                         error = in6_selectsrc(&dst_sa, NULL,
  518                             NULL, &ro, NULL, &oifp, &src_in);
  519                         if (error) {
  520                                 char ip6buf[INET6_ADDRSTRLEN];
  521                                 nd6log((LOG_DEBUG,
  522                                     "nd6_ns_output: source can't be "
  523                                     "determined: dst=%s, error=%d\n",
  524                                     ip6_sprintf(ip6buf, &dst_sa.sin6_addr),
  525                                     error));
  526                                 goto bad;
  527                         }
  528                         ip6->ip6_src = src_in;
  529                 }
  530         } else {
  531                 /*
  532                  * Source address for DAD packet must always be IPv6
  533                  * unspecified address. (0::0)
  534                  * We actually don't have to 0-clear the address (we did it
  535                  * above), but we do so here explicitly to make the intention
  536                  * clearer.
  537                  */
  538                 bzero(&ip6->ip6_src, sizeof(ip6->ip6_src));
  539         }
  540         nd_ns = (struct nd_neighbor_solicit *)(ip6 + 1);
  541         nd_ns->nd_ns_type = ND_NEIGHBOR_SOLICIT;
  542         nd_ns->nd_ns_code = 0;
  543         nd_ns->nd_ns_reserved = 0;
  544         nd_ns->nd_ns_target = *taddr6;
  545         in6_clearscope(&nd_ns->nd_ns_target); /* XXX */
  546 
  547         /*
  548          * Add source link-layer address option.
  549          *
  550          *                              spec            implementation
  551          *                              ---             ---
  552          * DAD packet                   MUST NOT        do not add the option
  553          * there's no link layer address:
  554          *                              impossible      do not add the option
  555          * there's link layer address:
  556          *      Multicast NS            MUST add one    add the option
  557          *      Unicast NS              SHOULD add one  add the option
  558          */
  559         if (!dad && (mac = nd6_ifptomac(ifp))) {
  560                 int optlen = sizeof(struct nd_opt_hdr) + ifp->if_addrlen;
  561                 struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)(nd_ns + 1);
  562                 /* 8 byte alignments... */
  563                 optlen = (optlen + 7) & ~7;
  564 
  565                 m->m_pkthdr.len += optlen;
  566                 m->m_len += optlen;
  567                 icmp6len += optlen;
  568                 bzero((caddr_t)nd_opt, optlen);
  569                 nd_opt->nd_opt_type = ND_OPT_SOURCE_LINKADDR;
  570                 nd_opt->nd_opt_len = optlen >> 3;
  571                 bcopy(mac, (caddr_t)(nd_opt + 1), ifp->if_addrlen);
  572         }
  573 
  574         ip6->ip6_plen = htons((u_short)icmp6len);
  575         nd_ns->nd_ns_cksum = 0;
  576         nd_ns->nd_ns_cksum =
  577             in6_cksum(m, IPPROTO_ICMPV6, sizeof(*ip6), icmp6len);
  578 
  579         if (send_sendso_input_hook != NULL) {
  580                 mtag = m_tag_get(PACKET_TAG_ND_OUTGOING,
  581                         sizeof(unsigned short), M_NOWAIT);
  582                 if (mtag == NULL)
  583                         goto bad;
  584                 *(unsigned short *)(mtag + 1) = nd_ns->nd_ns_type;
  585                 m_tag_prepend(m, mtag);
  586         }
  587 
  588         ip6_output(m, NULL, &ro, dad ? IPV6_UNSPECSRC : 0, &im6o, NULL, NULL);
  589         icmp6_ifstat_inc(ifp, ifs6_out_msg);
  590         icmp6_ifstat_inc(ifp, ifs6_out_neighborsolicit);
  591         ICMP6STAT_INC(icp6s_outhist[ND_NEIGHBOR_SOLICIT]);
  592 
  593         /* We don't cache this route. */
  594         RO_RTFREE(&ro);
  595 
  596         return;
  597 
  598   bad:
  599         if (ro.ro_rt) {
  600                 RTFREE(ro.ro_rt);
  601         }
  602         m_freem(m);
  603         return;
  604 }
  605 
  606 /*
  607  * Neighbor advertisement input handling.
  608  *
  609  * Based on RFC 2461
  610  * Based on RFC 2462 (duplicate address detection)
  611  *
  612  * the following items are not implemented yet:
  613  * - proxy advertisement delay rule (RFC2461 7.2.8, last paragraph, SHOULD)
  614  * - anycast advertisement delay rule (RFC2461 7.2.7, SHOULD)
  615  */
  616 void
  617 nd6_na_input(struct mbuf *m, int off, int icmp6len)
  618 {
  619         struct ifnet *ifp = m->m_pkthdr.rcvif;
  620         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
  621         struct nd_neighbor_advert *nd_na;
  622         struct in6_addr daddr6 = ip6->ip6_dst;
  623         struct in6_addr taddr6;
  624         int flags;
  625         int is_router;
  626         int is_solicited;
  627         int is_override;
  628         char *lladdr = NULL;
  629         int lladdrlen = 0;
  630         int checklink = 0;
  631         struct ifaddr *ifa;
  632         struct llentry *ln = NULL;
  633         union nd_opts ndopts;
  634         struct mbuf *chain = NULL;
  635         struct m_tag *mtag;
  636         struct sockaddr_in6 sin6;
  637         char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
  638 
  639         if (ip6->ip6_hlim != 255) {
  640                 nd6log((LOG_ERR,
  641                     "nd6_na_input: invalid hlim (%d) from %s to %s on %s\n",
  642                     ip6->ip6_hlim, ip6_sprintf(ip6bufs, &ip6->ip6_src),
  643                     ip6_sprintf(ip6bufd, &ip6->ip6_dst), if_name(ifp)));
  644                 goto bad;
  645         }
  646 
  647 #ifndef PULLDOWN_TEST
  648         IP6_EXTHDR_CHECK(m, off, icmp6len,);
  649         nd_na = (struct nd_neighbor_advert *)((caddr_t)ip6 + off);
  650 #else
  651         IP6_EXTHDR_GET(nd_na, struct nd_neighbor_advert *, m, off, icmp6len);
  652         if (nd_na == NULL) {
  653                 ICMP6STAT_INC(icp6s_tooshort);
  654                 return;
  655         }
  656 #endif
  657 
  658         flags = nd_na->nd_na_flags_reserved;
  659         is_router = ((flags & ND_NA_FLAG_ROUTER) != 0);
  660         is_solicited = ((flags & ND_NA_FLAG_SOLICITED) != 0);
  661         is_override = ((flags & ND_NA_FLAG_OVERRIDE) != 0);
  662 
  663         taddr6 = nd_na->nd_na_target;
  664         if (in6_setscope(&taddr6, ifp, NULL))
  665                 goto bad;       /* XXX: impossible */
  666 
  667         if (IN6_IS_ADDR_MULTICAST(&taddr6)) {
  668                 nd6log((LOG_ERR,
  669                     "nd6_na_input: invalid target address %s\n",
  670                     ip6_sprintf(ip6bufs, &taddr6)));
  671                 goto bad;
  672         }
  673         if (IN6_IS_ADDR_MULTICAST(&daddr6))
  674                 if (is_solicited) {
  675                         nd6log((LOG_ERR,
  676                             "nd6_na_input: a solicited adv is multicasted\n"));
  677                         goto bad;
  678                 }
  679 
  680         icmp6len -= sizeof(*nd_na);
  681         nd6_option_init(nd_na + 1, icmp6len, &ndopts);
  682         if (nd6_options(&ndopts) < 0) {
  683                 nd6log((LOG_INFO,
  684                     "nd6_na_input: invalid ND option, ignored\n"));
  685                 /* nd6_options have incremented stats */
  686                 goto freeit;
  687         }
  688 
  689         if (ndopts.nd_opts_tgt_lladdr) {
  690                 lladdr = (char *)(ndopts.nd_opts_tgt_lladdr + 1);
  691                 lladdrlen = ndopts.nd_opts_tgt_lladdr->nd_opt_len << 3;
  692         }
  693 
  694         /*
  695          * This effectively disables the DAD check on a non-master CARP
  696          * address.
  697          */
  698         if (ifp->if_carp)
  699                 ifa = (*carp_iamatch6_p)(ifp, &taddr6);
  700         else
  701                 ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
  702 
  703         /*
  704          * Target address matches one of my interface address.
  705          *
  706          * If my address is tentative, this means that there's somebody
  707          * already using the same address as mine.  This indicates DAD failure.
  708          * This is defined in RFC 2462.
  709          *
  710          * Otherwise, process as defined in RFC 2461.
  711          */
  712         if (ifa
  713          && (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_TENTATIVE)) {
  714                 ifa_free(ifa);
  715                 nd6_dad_na_input(ifa);
  716                 goto freeit;
  717         }
  718 
  719         /* Just for safety, maybe unnecessary. */
  720         if (ifa) {
  721                 ifa_free(ifa);
  722                 log(LOG_ERR,
  723                     "nd6_na_input: duplicate IP6 address %s\n",
  724                     ip6_sprintf(ip6bufs, &taddr6));
  725                 goto freeit;
  726         }
  727 
  728         if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
  729                 nd6log((LOG_INFO, "nd6_na_input: lladdrlen mismatch for %s "
  730                     "(if %d, NA packet %d)\n", ip6_sprintf(ip6bufs, &taddr6),
  731                     ifp->if_addrlen, lladdrlen - 2));
  732                 goto bad;
  733         }
  734 
  735         /*
  736          * If no neighbor cache entry is found, NA SHOULD silently be
  737          * discarded.
  738          */
  739         IF_AFDATA_LOCK(ifp);
  740         ln = nd6_lookup(&taddr6, LLE_EXCLUSIVE, ifp);
  741         IF_AFDATA_UNLOCK(ifp);
  742         if (ln == NULL) {
  743                 goto freeit;
  744         }
  745 
  746         if (ln->ln_state == ND6_LLINFO_INCOMPLETE) {
  747                 /*
  748                  * If the link-layer has address, and no lladdr option came,
  749                  * discard the packet.
  750                  */
  751                 if (ifp->if_addrlen && lladdr == NULL) {
  752                         goto freeit;
  753                 }
  754 
  755                 /*
  756                  * Record link-layer address, and update the state.
  757                  */
  758                 bcopy(lladdr, &ln->ll_addr, ifp->if_addrlen);
  759                 ln->la_flags |= LLE_VALID;
  760                 EVENTHANDLER_INVOKE(lle_event, ln, LLENTRY_RESOLVED);
  761                 if (is_solicited) {
  762                         ln->ln_state = ND6_LLINFO_REACHABLE;
  763                         ln->ln_byhint = 0;
  764                         if (!ND6_LLINFO_PERMANENT(ln)) {
  765                                 nd6_llinfo_settimer_locked(ln,
  766                                     (long)ND_IFINFO(ln->lle_tbl->llt_ifp)->reachable * hz);
  767                         }
  768                 } else {
  769                         ln->ln_state = ND6_LLINFO_STALE;
  770                         nd6_llinfo_settimer_locked(ln, (long)V_nd6_gctimer * hz);
  771                 }
  772                 if ((ln->ln_router = is_router) != 0) {
  773                         /*
  774                          * This means a router's state has changed from
  775                          * non-reachable to probably reachable, and might
  776                          * affect the status of associated prefixes..
  777                          */
  778                         checklink = 1;
  779                 }
  780         } else {
  781                 int llchange;
  782 
  783                 /*
  784                  * Check if the link-layer address has changed or not.
  785                  */
  786                 if (lladdr == NULL)
  787                         llchange = 0;
  788                 else {
  789                         if (ln->la_flags & LLE_VALID) {
  790                                 if (bcmp(lladdr, &ln->ll_addr, ifp->if_addrlen))
  791                                         llchange = 1;
  792                                 else
  793                                         llchange = 0;
  794                         } else
  795                                 llchange = 1;
  796                 }
  797 
  798                 /*
  799                  * This is VERY complex.  Look at it with care.
  800                  *
  801                  * override solicit lladdr llchange     action
  802                  *                                      (L: record lladdr)
  803                  *
  804                  *      0       0       n       --      (2c)
  805                  *      0       0       y       n       (2b) L
  806                  *      0       0       y       y       (1)    REACHABLE->STALE
  807                  *      0       1       n       --      (2c)   *->REACHABLE
  808                  *      0       1       y       n       (2b) L *->REACHABLE
  809                  *      0       1       y       y       (1)    REACHABLE->STALE
  810                  *      1       0       n       --      (2a)
  811                  *      1       0       y       n       (2a) L
  812                  *      1       0       y       y       (2a) L *->STALE
  813                  *      1       1       n       --      (2a)   *->REACHABLE
  814                  *      1       1       y       n       (2a) L *->REACHABLE
  815                  *      1       1       y       y       (2a) L *->REACHABLE
  816                  */
  817                 if (!is_override && (lladdr != NULL && llchange)) {  /* (1) */
  818                         /*
  819                          * If state is REACHABLE, make it STALE.
  820                          * no other updates should be done.
  821                          */
  822                         if (ln->ln_state == ND6_LLINFO_REACHABLE) {
  823                                 ln->ln_state = ND6_LLINFO_STALE;
  824                                 nd6_llinfo_settimer_locked(ln, (long)V_nd6_gctimer * hz);
  825                         }
  826                         goto freeit;
  827                 } else if (is_override                             /* (2a) */
  828                         || (!is_override && (lladdr != NULL && !llchange)) /* (2b) */
  829                         || lladdr == NULL) {                       /* (2c) */
  830                         /*
  831                          * Update link-local address, if any.
  832                          */
  833                         if (lladdr != NULL) {
  834                                 bcopy(lladdr, &ln->ll_addr, ifp->if_addrlen);
  835                                 ln->la_flags |= LLE_VALID;
  836                                 EVENTHANDLER_INVOKE(lle_event, ln,
  837                                     LLENTRY_RESOLVED);
  838                         }
  839 
  840                         /*
  841                          * If solicited, make the state REACHABLE.
  842                          * If not solicited and the link-layer address was
  843                          * changed, make it STALE.
  844                          */
  845                         if (is_solicited) {
  846                                 ln->ln_state = ND6_LLINFO_REACHABLE;
  847                                 ln->ln_byhint = 0;
  848                                 if (!ND6_LLINFO_PERMANENT(ln)) {
  849                                         nd6_llinfo_settimer_locked(ln,
  850                                             (long)ND_IFINFO(ifp)->reachable * hz);
  851                                 }
  852                         } else {
  853                                 if (lladdr != NULL && llchange) {
  854                                         ln->ln_state = ND6_LLINFO_STALE;
  855                                         nd6_llinfo_settimer_locked(ln,
  856                                             (long)V_nd6_gctimer * hz);
  857                                 }
  858                         }
  859                 }
  860 
  861                 if (ln->ln_router && !is_router) {
  862                         /*
  863                          * The peer dropped the router flag.
  864                          * Remove the sender from the Default Router List and
  865                          * update the Destination Cache entries.
  866                          */
  867                         struct nd_defrouter *dr;
  868                         struct in6_addr *in6;
  869 
  870                         in6 = &L3_ADDR_SIN6(ln)->sin6_addr;
  871 
  872                         /*
  873                          * Lock to protect the default router list.
  874                          * XXX: this might be unnecessary, since this function
  875                          * is only called under the network software interrupt
  876                          * context.  However, we keep it just for safety.
  877                          */
  878                         dr = defrouter_lookup(in6, ln->lle_tbl->llt_ifp);
  879                         if (dr)
  880                                 defrtrlist_del(dr);
  881                         else if (ND_IFINFO(ln->lle_tbl->llt_ifp)->flags &
  882                             ND6_IFF_ACCEPT_RTADV) {
  883                                 /*
  884                                  * Even if the neighbor is not in the default
  885                                  * router list, the neighbor may be used
  886                                  * as a next hop for some destinations
  887                                  * (e.g. redirect case). So we must
  888                                  * call rt6_flush explicitly.
  889                                  */
  890                                 rt6_flush(&ip6->ip6_src, ifp);
  891                         }
  892                 }
  893                 ln->ln_router = is_router;
  894         }
  895         /* XXX - QL
  896          *  Does this matter?
  897          *  rt->rt_flags &= ~RTF_REJECT;
  898          */
  899         ln->la_asked = 0;
  900         if (ln->la_hold) {
  901                 struct mbuf *m_hold, *m_hold_next;
  902 
  903                 /*
  904                  * reset the la_hold in advance, to explicitly
  905                  * prevent a la_hold lookup in nd6_output()
  906                  * (wouldn't happen, though...)
  907                  */
  908                 for (m_hold = ln->la_hold, ln->la_hold = NULL;
  909                     m_hold; m_hold = m_hold_next) {
  910                         m_hold_next = m_hold->m_nextpkt;
  911                         m_hold->m_nextpkt = NULL;
  912                         /*
  913                          * we assume ifp is not a loopback here, so just set
  914                          * the 2nd argument as the 1st one.
  915                          */
  916 
  917                         if (send_sendso_input_hook != NULL) {
  918                                 mtag = m_tag_get(PACKET_TAG_ND_OUTGOING,
  919                                     sizeof(unsigned short), M_NOWAIT);
  920                                 if (mtag == NULL)
  921                                         goto bad;
  922                                 m_tag_prepend(m, mtag);
  923                         }
  924 
  925                         nd6_output_lle(ifp, ifp, m_hold, L3_ADDR_SIN6(ln), NULL, ln, &chain);
  926                 }
  927         }
  928  freeit:
  929         if (ln != NULL) {
  930                 if (chain)
  931                         memcpy(&sin6, L3_ADDR_SIN6(ln), sizeof(sin6));
  932                 LLE_WUNLOCK(ln);
  933 
  934                 if (chain)
  935                         nd6_output_flush(ifp, ifp, chain, &sin6, NULL);
  936         }
  937         if (checklink)
  938                 pfxlist_onlink_check();
  939 
  940         m_freem(m);
  941         return;
  942 
  943  bad:
  944         if (ln != NULL)
  945                 LLE_WUNLOCK(ln);
  946 
  947         ICMP6STAT_INC(icp6s_badna);
  948         m_freem(m);
  949 }
  950 
  951 /*
  952  * Neighbor advertisement output handling.
  953  *
  954  * Based on RFC 2461
  955  *
  956  * the following items are not implemented yet:
  957  * - proxy advertisement delay rule (RFC2461 7.2.8, last paragraph, SHOULD)
  958  * - anycast advertisement delay rule (RFC2461 7.2.7, SHOULD)
  959  *
  960  * tlladdr - 1 if include target link-layer address
  961  * sdl0 - sockaddr_dl (= proxy NA) or NULL
  962  */
  963 static void
  964 nd6_na_output_fib(struct ifnet *ifp, const struct in6_addr *daddr6_0,
  965     const struct in6_addr *taddr6, u_long flags, int tlladdr,
  966     struct sockaddr *sdl0, u_int fibnum)
  967 {
  968         struct mbuf *m;
  969         struct m_tag *mtag;
  970         struct ifnet *oifp;
  971         struct ip6_hdr *ip6;
  972         struct nd_neighbor_advert *nd_na;
  973         struct ip6_moptions im6o;
  974         struct in6_addr src, daddr6;
  975         struct sockaddr_in6 dst_sa;
  976         int icmp6len, maxlen, error;
  977         caddr_t mac = NULL;
  978         struct route_in6 ro;
  979 
  980         bzero(&ro, sizeof(ro));
  981 
  982         daddr6 = *daddr6_0;     /* make a local copy for modification */
  983 
  984         /* estimate the size of message */
  985         maxlen = sizeof(*ip6) + sizeof(*nd_na);
  986         maxlen += (sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7;
  987         if (max_linkhdr + maxlen >= MCLBYTES) {
  988 #ifdef DIAGNOSTIC
  989                 printf("nd6_na_output: max_linkhdr + maxlen >= MCLBYTES "
  990                     "(%d + %d > %d)\n", max_linkhdr, maxlen, MCLBYTES);
  991 #endif
  992                 return;
  993         }
  994 
  995         if (max_linkhdr + maxlen > MHLEN)
  996                 m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
  997         else
  998                 m = m_gethdr(M_NOWAIT, MT_DATA);
  999         if (m == NULL)
 1000                 return;
 1001         M_SETFIB(m, fibnum);
 1002 
 1003         if (IN6_IS_ADDR_MULTICAST(&daddr6)) {
 1004                 m->m_flags |= M_MCAST;
 1005                 im6o.im6o_multicast_ifp = ifp;
 1006                 im6o.im6o_multicast_hlim = 255;
 1007                 im6o.im6o_multicast_loop = 0;
 1008         }
 1009 
 1010         icmp6len = sizeof(*nd_na);
 1011         m->m_pkthdr.len = m->m_len = sizeof(struct ip6_hdr) + icmp6len;
 1012         m->m_data += max_linkhdr;       /* or MH_ALIGN() equivalent? */
 1013 
 1014         /* fill neighbor advertisement packet */
 1015         ip6 = mtod(m, struct ip6_hdr *);
 1016         ip6->ip6_flow = 0;
 1017         ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
 1018         ip6->ip6_vfc |= IPV6_VERSION;
 1019         ip6->ip6_nxt = IPPROTO_ICMPV6;
 1020         ip6->ip6_hlim = 255;
 1021         if (IN6_IS_ADDR_UNSPECIFIED(&daddr6)) {
 1022                 /* reply to DAD */
 1023                 daddr6.s6_addr16[0] = IPV6_ADDR_INT16_MLL;
 1024                 daddr6.s6_addr16[1] = 0;
 1025                 daddr6.s6_addr32[1] = 0;
 1026                 daddr6.s6_addr32[2] = 0;
 1027                 daddr6.s6_addr32[3] = IPV6_ADDR_INT32_ONE;
 1028                 if (in6_setscope(&daddr6, ifp, NULL))
 1029                         goto bad;
 1030 
 1031                 flags &= ~ND_NA_FLAG_SOLICITED;
 1032         }
 1033         ip6->ip6_dst = daddr6;
 1034         bzero(&dst_sa, sizeof(struct sockaddr_in6));
 1035         dst_sa.sin6_family = AF_INET6;
 1036         dst_sa.sin6_len = sizeof(struct sockaddr_in6);
 1037         dst_sa.sin6_addr = daddr6;
 1038 
 1039         /*
 1040          * Select a source whose scope is the same as that of the dest.
 1041          */
 1042         bcopy(&dst_sa, &ro.ro_dst, sizeof(dst_sa));
 1043         oifp = ifp;
 1044         error = in6_selectsrc(&dst_sa, NULL, NULL, &ro, NULL, &oifp, &src);
 1045         if (error) {
 1046                 char ip6buf[INET6_ADDRSTRLEN];
 1047                 nd6log((LOG_DEBUG, "nd6_na_output: source can't be "
 1048                     "determined: dst=%s, error=%d\n",
 1049                     ip6_sprintf(ip6buf, &dst_sa.sin6_addr), error));
 1050                 goto bad;
 1051         }
 1052         ip6->ip6_src = src;
 1053         nd_na = (struct nd_neighbor_advert *)(ip6 + 1);
 1054         nd_na->nd_na_type = ND_NEIGHBOR_ADVERT;
 1055         nd_na->nd_na_code = 0;
 1056         nd_na->nd_na_target = *taddr6;
 1057         in6_clearscope(&nd_na->nd_na_target); /* XXX */
 1058 
 1059         /*
 1060          * "tlladdr" indicates NS's condition for adding tlladdr or not.
 1061          * see nd6_ns_input() for details.
 1062          * Basically, if NS packet is sent to unicast/anycast addr,
 1063          * target lladdr option SHOULD NOT be included.
 1064          */
 1065         if (tlladdr) {
 1066                 /*
 1067                  * sdl0 != NULL indicates proxy NA.  If we do proxy, use
 1068                  * lladdr in sdl0.  If we are not proxying (sending NA for
 1069                  * my address) use lladdr configured for the interface.
 1070                  */
 1071                 if (sdl0 == NULL) {
 1072                         if (ifp->if_carp)
 1073                                 mac = (*carp_macmatch6_p)(ifp, m, taddr6);
 1074                         if (mac == NULL)
 1075                                 mac = nd6_ifptomac(ifp);
 1076                 } else if (sdl0->sa_family == AF_LINK) {
 1077                         struct sockaddr_dl *sdl;
 1078                         sdl = (struct sockaddr_dl *)sdl0;
 1079                         if (sdl->sdl_alen == ifp->if_addrlen)
 1080                                 mac = LLADDR(sdl);
 1081                 }
 1082         }
 1083         if (tlladdr && mac) {
 1084                 int optlen = sizeof(struct nd_opt_hdr) + ifp->if_addrlen;
 1085                 struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)(nd_na + 1);
 1086 
 1087                 /* roundup to 8 bytes alignment! */
 1088                 optlen = (optlen + 7) & ~7;
 1089 
 1090                 m->m_pkthdr.len += optlen;
 1091                 m->m_len += optlen;
 1092                 icmp6len += optlen;
 1093                 bzero((caddr_t)nd_opt, optlen);
 1094                 nd_opt->nd_opt_type = ND_OPT_TARGET_LINKADDR;
 1095                 nd_opt->nd_opt_len = optlen >> 3;
 1096                 bcopy(mac, (caddr_t)(nd_opt + 1), ifp->if_addrlen);
 1097         } else
 1098                 flags &= ~ND_NA_FLAG_OVERRIDE;
 1099 
 1100         ip6->ip6_plen = htons((u_short)icmp6len);
 1101         nd_na->nd_na_flags_reserved = flags;
 1102         nd_na->nd_na_cksum = 0;
 1103         nd_na->nd_na_cksum =
 1104             in6_cksum(m, IPPROTO_ICMPV6, sizeof(struct ip6_hdr), icmp6len);
 1105 
 1106         if (send_sendso_input_hook != NULL) {
 1107                 mtag = m_tag_get(PACKET_TAG_ND_OUTGOING,
 1108                     sizeof(unsigned short), M_NOWAIT);
 1109                 if (mtag == NULL)
 1110                         goto bad;
 1111                 *(unsigned short *)(mtag + 1) = nd_na->nd_na_type;
 1112                 m_tag_prepend(m, mtag);
 1113         }
 1114 
 1115         ip6_output(m, NULL, &ro, 0, &im6o, NULL, NULL);
 1116         icmp6_ifstat_inc(ifp, ifs6_out_msg);
 1117         icmp6_ifstat_inc(ifp, ifs6_out_neighboradvert);
 1118         ICMP6STAT_INC(icp6s_outhist[ND_NEIGHBOR_ADVERT]);
 1119 
 1120         /* We don't cache this route. */
 1121         RO_RTFREE(&ro);
 1122 
 1123         return;
 1124 
 1125   bad:
 1126         if (ro.ro_rt) {
 1127                 RTFREE(ro.ro_rt);
 1128         }
 1129         m_freem(m);
 1130         return;
 1131 }
 1132 
 1133 #ifndef BURN_BRIDGES
 1134 void
 1135 nd6_na_output(struct ifnet *ifp, const struct in6_addr *daddr6_0,
 1136     const struct in6_addr *taddr6, u_long flags, int tlladdr,
 1137     struct sockaddr *sdl0)
 1138 {
 1139 
 1140         nd6_na_output_fib(ifp, daddr6_0, taddr6, flags, tlladdr, sdl0,
 1141             RT_DEFAULT_FIB);
 1142 }
 1143 #endif
 1144 
 1145 caddr_t
 1146 nd6_ifptomac(struct ifnet *ifp)
 1147 {
 1148         switch (ifp->if_type) {
 1149         case IFT_ARCNET:
 1150         case IFT_ETHER:
 1151         case IFT_FDDI:
 1152         case IFT_IEEE1394:
 1153 #ifdef IFT_L2VLAN
 1154         case IFT_L2VLAN:
 1155 #endif
 1156 #ifdef IFT_IEEE80211
 1157         case IFT_IEEE80211:
 1158 #endif
 1159         case IFT_INFINIBAND:
 1160         case IFT_BRIDGE:
 1161         case IFT_ISO88025:
 1162                 return IF_LLADDR(ifp);
 1163         default:
 1164                 return NULL;
 1165         }
 1166 }
 1167 
 1168 struct dadq {
 1169         TAILQ_ENTRY(dadq) dad_list;
 1170         struct ifaddr *dad_ifa;
 1171         int dad_count;          /* max NS to send */
 1172         int dad_ns_tcount;      /* # of trials to send NS */
 1173         int dad_ns_ocount;      /* NS sent so far */
 1174         int dad_ns_icount;
 1175         int dad_na_icount;
 1176         struct callout dad_timer_ch;
 1177         struct vnet *dad_vnet;
 1178 };
 1179 
 1180 static VNET_DEFINE(TAILQ_HEAD(, dadq), dadq);
 1181 VNET_DEFINE(int, dad_init) = 0;
 1182 #define V_dadq                          VNET(dadq)
 1183 #define V_dad_init                      VNET(dad_init)
 1184 
 1185 static struct dadq *
 1186 nd6_dad_find(struct ifaddr *ifa)
 1187 {
 1188         struct dadq *dp;
 1189 
 1190         TAILQ_FOREACH(dp, &V_dadq, dad_list)
 1191                 if (dp->dad_ifa == ifa)
 1192                         return (dp);
 1193 
 1194         return (NULL);
 1195 }
 1196 
 1197 static void
 1198 nd6_dad_starttimer(struct dadq *dp, int ticks)
 1199 {
 1200 
 1201         callout_reset(&dp->dad_timer_ch, ticks,
 1202             (void (*)(void *))nd6_dad_timer, (void *)dp);
 1203 }
 1204 
 1205 static void
 1206 nd6_dad_stoptimer(struct dadq *dp)
 1207 {
 1208 
 1209         callout_stop(&dp->dad_timer_ch);
 1210 }
 1211 
 1212 /*
 1213  * Start Duplicate Address Detection (DAD) for specified interface address.
 1214  */
 1215 void
 1216 nd6_dad_start(struct ifaddr *ifa, int delay)
 1217 {
 1218         struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
 1219         struct dadq *dp;
 1220         char ip6buf[INET6_ADDRSTRLEN];
 1221 
 1222         if (!V_dad_init) {
 1223                 TAILQ_INIT(&V_dadq);
 1224                 V_dad_init++;
 1225         }
 1226 
 1227         /*
 1228          * If we don't need DAD, don't do it.
 1229          * There are several cases:
 1230          * - DAD is disabled (ip6_dad_count == 0)
 1231          * - the interface address is anycast
 1232          */
 1233         if (!(ia->ia6_flags & IN6_IFF_TENTATIVE)) {
 1234                 log(LOG_DEBUG,
 1235                         "nd6_dad_start: called with non-tentative address "
 1236                         "%s(%s)\n",
 1237                         ip6_sprintf(ip6buf, &ia->ia_addr.sin6_addr),
 1238                         ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
 1239                 return;
 1240         }
 1241         if (ia->ia6_flags & IN6_IFF_ANYCAST) {
 1242                 ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
 1243                 return;
 1244         }
 1245         if (!V_ip6_dad_count) {
 1246                 ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
 1247                 return;
 1248         }
 1249         if (ifa->ifa_ifp == NULL)
 1250                 panic("nd6_dad_start: ifa->ifa_ifp == NULL");
 1251         if (!(ifa->ifa_ifp->if_flags & IFF_UP)) {
 1252                 return;
 1253         }
 1254         if (ND_IFINFO(ifa->ifa_ifp)->flags & ND6_IFF_IFDISABLED)
 1255                 return;
 1256         if (nd6_dad_find(ifa) != NULL) {
 1257                 /* DAD already in progress */
 1258                 return;
 1259         }
 1260 
 1261         dp = malloc(sizeof(*dp), M_IP6NDP, M_NOWAIT);
 1262         if (dp == NULL) {
 1263                 log(LOG_ERR, "nd6_dad_start: memory allocation failed for "
 1264                         "%s(%s)\n",
 1265                         ip6_sprintf(ip6buf, &ia->ia_addr.sin6_addr),
 1266                         ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
 1267                 return;
 1268         }
 1269         bzero(dp, sizeof(*dp));
 1270         callout_init(&dp->dad_timer_ch, 0);
 1271 #ifdef VIMAGE
 1272         dp->dad_vnet = curvnet;
 1273 #endif
 1274         TAILQ_INSERT_TAIL(&V_dadq, (struct dadq *)dp, dad_list);
 1275 
 1276         nd6log((LOG_DEBUG, "%s: starting DAD for %s\n", if_name(ifa->ifa_ifp),
 1277             ip6_sprintf(ip6buf, &ia->ia_addr.sin6_addr)));
 1278 
 1279         /*
 1280          * Send NS packet for DAD, ip6_dad_count times.
 1281          * Note that we must delay the first transmission, if this is the
 1282          * first packet to be sent from the interface after interface
 1283          * (re)initialization.
 1284          */
 1285         dp->dad_ifa = ifa;
 1286         ifa_ref(ifa);   /* just for safety */
 1287         dp->dad_count = V_ip6_dad_count;
 1288         dp->dad_ns_icount = dp->dad_na_icount = 0;
 1289         dp->dad_ns_ocount = dp->dad_ns_tcount = 0;
 1290         if (delay == 0) {
 1291                 nd6_dad_ns_output(dp, ifa);
 1292                 nd6_dad_starttimer(dp,
 1293                     (long)ND_IFINFO(ifa->ifa_ifp)->retrans * hz / 1000);
 1294         } else {
 1295                 nd6_dad_starttimer(dp, delay);
 1296         }
 1297 }
 1298 
 1299 /*
 1300  * terminate DAD unconditionally.  used for address removals.
 1301  */
 1302 void
 1303 nd6_dad_stop(struct ifaddr *ifa)
 1304 {
 1305         struct dadq *dp;
 1306 
 1307         if (!V_dad_init)
 1308                 return;
 1309         dp = nd6_dad_find(ifa);
 1310         if (!dp) {
 1311                 /* DAD wasn't started yet */
 1312                 return;
 1313         }
 1314 
 1315         nd6_dad_stoptimer(dp);
 1316 
 1317         TAILQ_REMOVE(&V_dadq, (struct dadq *)dp, dad_list);
 1318         free(dp, M_IP6NDP);
 1319         dp = NULL;
 1320         ifa_free(ifa);
 1321 }
 1322 
 1323 static void
 1324 nd6_dad_timer(struct dadq *dp)
 1325 {
 1326         CURVNET_SET(dp->dad_vnet);
 1327         struct ifaddr *ifa = dp->dad_ifa;
 1328         struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
 1329         char ip6buf[INET6_ADDRSTRLEN];
 1330 
 1331         /* Sanity check */
 1332         if (ia == NULL) {
 1333                 log(LOG_ERR, "nd6_dad_timer: called with null parameter\n");
 1334                 goto done;
 1335         }
 1336         if (ia->ia6_flags & IN6_IFF_DUPLICATED) {
 1337                 log(LOG_ERR, "nd6_dad_timer: called with duplicated address "
 1338                         "%s(%s)\n",
 1339                         ip6_sprintf(ip6buf, &ia->ia_addr.sin6_addr),
 1340                         ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
 1341                 goto done;
 1342         }
 1343         if ((ia->ia6_flags & IN6_IFF_TENTATIVE) == 0) {
 1344                 log(LOG_ERR, "nd6_dad_timer: called with non-tentative address "
 1345                         "%s(%s)\n",
 1346                         ip6_sprintf(ip6buf, &ia->ia_addr.sin6_addr),
 1347                         ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
 1348                 goto done;
 1349         }
 1350 
 1351         /* timeouted with IFF_{RUNNING,UP} check */
 1352         if (dp->dad_ns_tcount > V_dad_maxtry) {
 1353                 nd6log((LOG_INFO, "%s: could not run DAD, driver problem?\n",
 1354                     if_name(ifa->ifa_ifp)));
 1355 
 1356                 TAILQ_REMOVE(&V_dadq, (struct dadq *)dp, dad_list);
 1357                 free(dp, M_IP6NDP);
 1358                 dp = NULL;
 1359                 ifa_free(ifa);
 1360                 goto done;
 1361         }
 1362 
 1363         /* Need more checks? */
 1364         if (dp->dad_ns_ocount < dp->dad_count) {
 1365                 /*
 1366                  * We have more NS to go.  Send NS packet for DAD.
 1367                  */
 1368                 nd6_dad_ns_output(dp, ifa);
 1369                 nd6_dad_starttimer(dp,
 1370                     (long)ND_IFINFO(ifa->ifa_ifp)->retrans * hz / 1000);
 1371         } else {
 1372                 /*
 1373                  * We have transmitted sufficient number of DAD packets.
 1374                  * See what we've got.
 1375                  */
 1376                 int duplicate;
 1377 
 1378                 duplicate = 0;
 1379 
 1380                 if (dp->dad_na_icount) {
 1381                         /*
 1382                          * the check is in nd6_dad_na_input(),
 1383                          * but just in case
 1384                          */
 1385                         duplicate++;
 1386                 }
 1387 
 1388                 if (dp->dad_ns_icount) {
 1389                         /* We've seen NS, means DAD has failed. */
 1390                         duplicate++;
 1391                 }
 1392 
 1393                 if (duplicate) {
 1394                         /* (*dp) will be freed in nd6_dad_duplicated() */
 1395                         dp = NULL;
 1396                         nd6_dad_duplicated(ifa);
 1397                 } else {
 1398                         /*
 1399                          * We are done with DAD.  No NA came, no NS came.
 1400                          * No duplicate address found.
 1401                          */
 1402                         ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
 1403 
 1404                         nd6log((LOG_DEBUG,
 1405                             "%s: DAD complete for %s - no duplicates found\n",
 1406                             if_name(ifa->ifa_ifp),
 1407                             ip6_sprintf(ip6buf, &ia->ia_addr.sin6_addr)));
 1408 
 1409                         TAILQ_REMOVE(&V_dadq, (struct dadq *)dp, dad_list);
 1410                         free(dp, M_IP6NDP);
 1411                         dp = NULL;
 1412                         ifa_free(ifa);
 1413                 }
 1414         }
 1415 
 1416 done:
 1417         CURVNET_RESTORE();
 1418 }
 1419 
 1420 void
 1421 nd6_dad_duplicated(struct ifaddr *ifa)
 1422 {
 1423         struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
 1424         struct ifnet *ifp;
 1425         struct dadq *dp;
 1426         char ip6buf[INET6_ADDRSTRLEN];
 1427 
 1428         dp = nd6_dad_find(ifa);
 1429         if (dp == NULL) {
 1430                 log(LOG_ERR, "nd6_dad_duplicated: DAD structure not found\n");
 1431                 return;
 1432         }
 1433 
 1434         log(LOG_ERR, "%s: DAD detected duplicate IPv6 address %s: "
 1435             "NS in/out=%d/%d, NA in=%d\n",
 1436             if_name(ifa->ifa_ifp), ip6_sprintf(ip6buf, &ia->ia_addr.sin6_addr),
 1437             dp->dad_ns_icount, dp->dad_ns_ocount, dp->dad_na_icount);
 1438 
 1439         ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
 1440         ia->ia6_flags |= IN6_IFF_DUPLICATED;
 1441 
 1442         /* We are done with DAD, with duplicate address found. (failure) */
 1443         nd6_dad_stoptimer(dp);
 1444 
 1445         ifp = ifa->ifa_ifp;
 1446         log(LOG_ERR, "%s: DAD complete for %s - duplicate found\n",
 1447             if_name(ifp), ip6_sprintf(ip6buf, &ia->ia_addr.sin6_addr));
 1448         log(LOG_ERR, "%s: manual intervention required\n",
 1449             if_name(ifp));
 1450 
 1451         /*
 1452          * If the address is a link-local address formed from an interface
 1453          * identifier based on the hardware address which is supposed to be
 1454          * uniquely assigned (e.g., EUI-64 for an Ethernet interface), IP
 1455          * operation on the interface SHOULD be disabled.
 1456          * [RFC 4862, Section 5.4.5]
 1457          */
 1458         if (IN6_IS_ADDR_LINKLOCAL(&ia->ia_addr.sin6_addr)) {
 1459                 struct in6_addr in6;
 1460 
 1461                 /*
 1462                  * To avoid over-reaction, we only apply this logic when we are
 1463                  * very sure that hardware addresses are supposed to be unique.
 1464                  */
 1465                 switch (ifp->if_type) {
 1466                 case IFT_ETHER:
 1467                 case IFT_FDDI:
 1468                 case IFT_ATM:
 1469                 case IFT_IEEE1394:
 1470 #ifdef IFT_IEEE80211
 1471                 case IFT_IEEE80211:
 1472 #endif
 1473                 case IFT_INFINIBAND:
 1474                         in6 = ia->ia_addr.sin6_addr;
 1475                         if (in6_get_hw_ifid(ifp, &in6) == 0 &&
 1476                             IN6_ARE_ADDR_EQUAL(&ia->ia_addr.sin6_addr, &in6)) {
 1477                                 ND_IFINFO(ifp)->flags |= ND6_IFF_IFDISABLED;
 1478                                 log(LOG_ERR, "%s: possible hardware address "
 1479                                     "duplication detected, disable IPv6\n",
 1480                                     if_name(ifp));
 1481                         }
 1482                         break;
 1483                 }
 1484         }
 1485 
 1486         TAILQ_REMOVE(&V_dadq, (struct dadq *)dp, dad_list);
 1487         free(dp, M_IP6NDP);
 1488         dp = NULL;
 1489         ifa_free(ifa);
 1490 }
 1491 
 1492 static void
 1493 nd6_dad_ns_output(struct dadq *dp, struct ifaddr *ifa)
 1494 {
 1495         struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
 1496         struct ifnet *ifp = ifa->ifa_ifp;
 1497 
 1498         dp->dad_ns_tcount++;
 1499         if ((ifp->if_flags & IFF_UP) == 0) {
 1500                 return;
 1501         }
 1502         if ((ifp->if_drv_flags & IFF_DRV_RUNNING) == 0) {
 1503                 return;
 1504         }
 1505 
 1506         dp->dad_ns_ocount++;
 1507         nd6_ns_output(ifp, NULL, &ia->ia_addr.sin6_addr, NULL, 1);
 1508 }
 1509 
 1510 static void
 1511 nd6_dad_ns_input(struct ifaddr *ifa)
 1512 {
 1513         struct in6_ifaddr *ia;
 1514         struct ifnet *ifp;
 1515         const struct in6_addr *taddr6;
 1516         struct dadq *dp;
 1517         int duplicate;
 1518 
 1519         if (ifa == NULL)
 1520                 panic("ifa == NULL in nd6_dad_ns_input");
 1521 
 1522         ia = (struct in6_ifaddr *)ifa;
 1523         ifp = ifa->ifa_ifp;
 1524         taddr6 = &ia->ia_addr.sin6_addr;
 1525         duplicate = 0;
 1526         dp = nd6_dad_find(ifa);
 1527 
 1528         /* Quickhack - completely ignore DAD NS packets */
 1529         if (V_dad_ignore_ns) {
 1530                 char ip6buf[INET6_ADDRSTRLEN];
 1531                 nd6log((LOG_INFO,
 1532                     "nd6_dad_ns_input: ignoring DAD NS packet for "
 1533                     "address %s(%s)\n", ip6_sprintf(ip6buf, taddr6),
 1534                     if_name(ifa->ifa_ifp)));
 1535                 return;
 1536         }
 1537 
 1538         /*
 1539          * if I'm yet to start DAD, someone else started using this address
 1540          * first.  I have a duplicate and you win.
 1541          */
 1542         if (dp == NULL || dp->dad_ns_ocount == 0)
 1543                 duplicate++;
 1544 
 1545         /* XXX more checks for loopback situation - see nd6_dad_timer too */
 1546 
 1547         if (duplicate) {
 1548                 dp = NULL;      /* will be freed in nd6_dad_duplicated() */
 1549                 nd6_dad_duplicated(ifa);
 1550         } else {
 1551                 /*
 1552                  * not sure if I got a duplicate.
 1553                  * increment ns count and see what happens.
 1554                  */
 1555                 if (dp)
 1556                         dp->dad_ns_icount++;
 1557         }
 1558 }
 1559 
 1560 static void
 1561 nd6_dad_na_input(struct ifaddr *ifa)
 1562 {
 1563         struct dadq *dp;
 1564 
 1565         if (ifa == NULL)
 1566                 panic("ifa == NULL in nd6_dad_na_input");
 1567 
 1568         dp = nd6_dad_find(ifa);
 1569         if (dp)
 1570                 dp->dad_na_icount++;
 1571 
 1572         /* remove the address. */
 1573         nd6_dad_duplicated(ifa);
 1574 }

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