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

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    1 /*      $NetBSD: nd6_nbr.c,v 1.94 2009/04/18 14:58:05 tsutsui Exp $     */
    2 /*      $KAME: nd6_nbr.c,v 1.61 2001/02/10 16:06:14 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 <sys/cdefs.h>
   34 __KERNEL_RCSID(0, "$NetBSD: nd6_nbr.c,v 1.94 2009/04/18 14:58:05 tsutsui Exp $");
   35 
   36 #include "opt_inet.h"
   37 #include "opt_ipsec.h"
   38 
   39 #include <sys/param.h>
   40 #include <sys/systm.h>
   41 #include <sys/malloc.h>
   42 #include <sys/mbuf.h>
   43 #include <sys/socket.h>
   44 #include <sys/socketvar.h>
   45 #include <sys/sockio.h>
   46 #include <sys/time.h>
   47 #include <sys/kernel.h>
   48 #include <sys/errno.h>
   49 #include <sys/ioctl.h>
   50 #include <sys/syslog.h>
   51 #include <sys/queue.h>
   52 #include <sys/callout.h>
   53 
   54 #include <net/if.h>
   55 #include <net/if_types.h>
   56 #include <net/if_dl.h>
   57 #include <net/route.h>
   58 
   59 #include <netinet/in.h>
   60 #include <netinet/in_var.h>
   61 #include <netinet6/in6_var.h>
   62 #include <netinet6/in6_ifattach.h>
   63 #include <netinet/ip6.h>
   64 #include <netinet6/ip6_var.h>
   65 #include <netinet6/scope6_var.h>
   66 #include <netinet6/nd6.h>
   67 #include <netinet/icmp6.h>
   68 #include <netinet6/icmp6_private.h>
   69 
   70 #ifdef IPSEC
   71 #include <netinet6/ipsec.h>
   72 #endif
   73 
   74 #include "carp.h"
   75 #if NCARP > 0
   76 #include <netinet/ip_carp.h>
   77 #endif
   78 
   79 #include <net/net_osdep.h>
   80 
   81 struct dadq;
   82 static struct dadq *nd6_dad_find(struct ifaddr *);
   83 static void nd6_dad_starttimer(struct dadq *, int);
   84 static void nd6_dad_stoptimer(struct dadq *);
   85 static void nd6_dad_timer(struct ifaddr *);
   86 static void nd6_dad_ns_output(struct dadq *, struct ifaddr *);
   87 static void nd6_dad_ns_input(struct ifaddr *);
   88 static void nd6_dad_na_input(struct ifaddr *);
   89 
   90 static int dad_ignore_ns = 0;   /* ignore NS in DAD - specwise incorrect*/
   91 static int dad_maxtry = 15;     /* max # of *tries* to transmit DAD packet */
   92 
   93 /*
   94  * Input a Neighbor Solicitation Message.
   95  *
   96  * Based on RFC 2461
   97  * Based on RFC 2462 (duplicate address detection)
   98  */
   99 void
  100 nd6_ns_input(struct mbuf *m, int off, int icmp6len)
  101 {
  102         struct ifnet *ifp = m->m_pkthdr.rcvif;
  103         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
  104         struct nd_neighbor_solicit *nd_ns;
  105         struct in6_addr saddr6 = ip6->ip6_src;
  106         struct in6_addr daddr6 = ip6->ip6_dst;
  107         struct in6_addr taddr6;
  108         struct in6_addr myaddr6;
  109         char *lladdr = NULL;
  110         struct ifaddr *ifa;
  111         int lladdrlen = 0;
  112         int anycast = 0, proxy = 0, tentative = 0;
  113         int router = ip6_forwarding;
  114         int tlladdr;
  115         union nd_opts ndopts;
  116         const struct sockaddr_dl *proxydl = NULL;
  117 
  118         IP6_EXTHDR_GET(nd_ns, struct nd_neighbor_solicit *, m, off, icmp6len);
  119         if (nd_ns == NULL) {
  120                 ICMP6_STATINC(ICMP6_STAT_TOOSHORT);
  121                 return;
  122         }
  123         ip6 = mtod(m, struct ip6_hdr *); /* adjust pointer for safety */
  124         taddr6 = nd_ns->nd_ns_target;
  125         if (in6_setscope(&taddr6, ifp, NULL) != 0)
  126                 goto bad;
  127 
  128         if (ip6->ip6_hlim != 255) {
  129                 nd6log((LOG_ERR,
  130                     "nd6_ns_input: invalid hlim (%d) from %s to %s on %s\n",
  131                     ip6->ip6_hlim, ip6_sprintf(&ip6->ip6_src),
  132                     ip6_sprintf(&ip6->ip6_dst), if_name(ifp)));
  133                 goto bad;
  134         }
  135 
  136         if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) {
  137                 /* dst has to be a solicited node multicast address. */
  138                 /* don't check ifindex portion */
  139                 if (daddr6.s6_addr16[0] == IPV6_ADDR_INT16_MLL &&
  140                     daddr6.s6_addr32[1] == 0 &&
  141                     daddr6.s6_addr32[2] == IPV6_ADDR_INT32_ONE &&
  142                     daddr6.s6_addr8[12] == 0xff) {
  143                         ; /* good */
  144                 } else {
  145                         nd6log((LOG_INFO, "nd6_ns_input: bad DAD packet "
  146                             "(wrong ip6 dst)\n"));
  147                         goto bad;
  148                 }
  149         } else {
  150                 /*
  151                  * Make sure the source address is from a neighbor's address.
  152                  */
  153                 if (in6ifa_ifplocaladdr(ifp, &saddr6) == NULL) {
  154                         nd6log((LOG_INFO, "nd6_ns_input: "
  155                             "NS packet from non-neighbor\n"));
  156                         goto bad;
  157                 }
  158         }
  159 
  160 
  161         if (IN6_IS_ADDR_MULTICAST(&taddr6)) {
  162                 nd6log((LOG_INFO, "nd6_ns_input: bad NS target (multicast)\n"));
  163                 goto bad;
  164         }
  165 
  166         icmp6len -= sizeof(*nd_ns);
  167         nd6_option_init(nd_ns + 1, icmp6len, &ndopts);
  168         if (nd6_options(&ndopts) < 0) {
  169                 nd6log((LOG_INFO,
  170                     "nd6_ns_input: invalid ND option, ignored\n"));
  171                 /* nd6_options have incremented stats */
  172                 goto freeit;
  173         }
  174 
  175         if (ndopts.nd_opts_src_lladdr) {
  176                 lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1);
  177                 lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
  178         }
  179 
  180         if (IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src) && lladdr) {
  181                 nd6log((LOG_INFO, "nd6_ns_input: bad DAD packet "
  182                     "(link-layer address option)\n"));
  183                 goto bad;
  184         }
  185 
  186         /*
  187          * Attaching target link-layer address to the NA?
  188          * (RFC 2461 7.2.4)
  189          *
  190          * NS IP dst is multicast                       MUST add
  191          * Otherwise                                    MAY be omitted
  192          *
  193          * In this implementation, we omit the target link-layer address
  194          * in the "MAY" case. 
  195          */
  196 #if 0 /* too much! */
  197         ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &daddr6);
  198         if (ifa && (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_ANYCAST))
  199                 tlladdr = 0;
  200         else
  201 #endif
  202         if (!IN6_IS_ADDR_MULTICAST(&daddr6))
  203                 tlladdr = 0;
  204         else
  205                 tlladdr = 1;
  206 
  207         /*
  208          * Target address (taddr6) must be either:
  209          * (1) Valid unicast/anycast address for my receiving interface,
  210          * (2) Unicast address for which I'm offering proxy service, or
  211          * (3) "tentative" address on which DAD is being performed.
  212          */
  213         /* (1) and (3) check. */
  214 #if NCARP > 0
  215         if (ifp->if_carp && ifp->if_type != IFT_CARP)
  216                 ifa = carp_iamatch6(ifp->if_carp, &taddr6);
  217         else
  218                 ifa = NULL;
  219         if (!ifa)
  220                 ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
  221 #else
  222         ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
  223 #endif
  224 
  225         /* (2) check. */
  226         if (ifa == NULL) {
  227                 struct rtentry *rt;
  228                 struct sockaddr_in6 tsin6;
  229 
  230                 sockaddr_in6_init(&tsin6, &taddr6, 0, 0, 0);
  231 
  232                 rt = rtalloc1((struct sockaddr *)&tsin6, 0);
  233                 if (rt && (rt->rt_flags & RTF_ANNOUNCE) != 0 &&
  234                     rt->rt_gateway->sa_family == AF_LINK) {
  235                         /*
  236                          * proxy NDP for single entry
  237                          */
  238                         ifa = (struct ifaddr *)in6ifa_ifpforlinklocal(ifp,
  239                                 IN6_IFF_NOTREADY|IN6_IFF_ANYCAST);
  240                         if (ifa) {
  241                                 proxy = 1;
  242                                 proxydl = satocsdl(rt->rt_gateway);
  243                                 router = 0;     /* XXX */
  244                         }
  245                 }
  246                 if (rt)
  247                         rtfree(rt);
  248         }
  249         if (ifa == NULL) {
  250                 /*
  251                  * We've got an NS packet, and we don't have that address
  252                  * assigned for us.  We MUST silently ignore it.
  253                  * See RFC2461 7.2.3.
  254                  */
  255                 goto freeit;
  256         }
  257         myaddr6 = *IFA_IN6(ifa);
  258         anycast = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_ANYCAST;
  259         tentative = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_TENTATIVE;
  260         if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_DUPLICATED)
  261                 goto freeit;
  262 
  263         if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
  264                 nd6log((LOG_INFO, "nd6_ns_input: lladdrlen mismatch for %s "
  265                     "(if %d, NS packet %d)\n",
  266                     ip6_sprintf(&taddr6), ifp->if_addrlen, lladdrlen - 2));
  267                 goto bad;
  268         }
  269 
  270         if (IN6_ARE_ADDR_EQUAL(&myaddr6, &saddr6)) {
  271                 nd6log((LOG_INFO, "nd6_ns_input: duplicate IP6 address %s\n",
  272                     ip6_sprintf(&saddr6)));
  273                 goto freeit;
  274         }
  275 
  276         /*
  277          * We have neighbor solicitation packet, with target address equals to
  278          * one of my tentative address.
  279          *
  280          * src addr     how to process?
  281          * ---          ---
  282          * multicast    of course, invalid (rejected in ip6_input)
  283          * unicast      somebody is doing address resolution -> ignore
  284          * unspec       dup address detection
  285          *
  286          * The processing is defined in RFC 2462.
  287          */
  288         if (tentative) {
  289                 /*
  290                  * If source address is unspecified address, it is for
  291                  * duplicate address detection.
  292                  *
  293                  * If not, the packet is for addess resolution;
  294                  * silently ignore it.
  295                  */
  296                 if (IN6_IS_ADDR_UNSPECIFIED(&saddr6))
  297                         nd6_dad_ns_input(ifa);
  298 
  299                 goto freeit;
  300         }
  301 
  302         /*
  303          * If the source address is unspecified address, entries must not
  304          * be created or updated.
  305          * It looks that sender is performing DAD.  Output NA toward
  306          * all-node multicast address, to tell the sender that I'm using
  307          * the address.
  308          * S bit ("solicited") must be zero.
  309          */
  310         if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) {
  311                 struct in6_addr in6_all;
  312 
  313                 in6_all = in6addr_linklocal_allnodes;
  314                 if (in6_setscope(&in6_all, ifp, NULL) != 0)
  315                         goto bad;
  316                 nd6_na_output(ifp, &in6_all, &taddr6,
  317                     ((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE) |
  318                     (ip6_forwarding ? ND_NA_FLAG_ROUTER : 0),
  319                     tlladdr, (const struct sockaddr *)proxydl);
  320                 goto freeit;
  321         }
  322 
  323         nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen, ND_NEIGHBOR_SOLICIT, 0);
  324 
  325         nd6_na_output(ifp, &saddr6, &taddr6,
  326             ((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE) |
  327             (router ? ND_NA_FLAG_ROUTER : 0) | ND_NA_FLAG_SOLICITED,
  328             tlladdr, (const struct sockaddr *)proxydl);
  329  freeit:
  330         m_freem(m);
  331         return;
  332 
  333  bad:
  334         nd6log((LOG_ERR, "nd6_ns_input: src=%s\n", ip6_sprintf(&saddr6)));
  335         nd6log((LOG_ERR, "nd6_ns_input: dst=%s\n", ip6_sprintf(&daddr6)));
  336         nd6log((LOG_ERR, "nd6_ns_input: tgt=%s\n", ip6_sprintf(&taddr6)));
  337         ICMP6_STATINC(ICMP6_STAT_BADNS);
  338         m_freem(m);
  339 }
  340 
  341 /*
  342  * Output a Neighbor Solicitation Message. Caller specifies:
  343  *      - ICMP6 header source IP6 address
  344  *      - ND6 header target IP6 address
  345  *      - ND6 header source datalink address
  346  *
  347  * Based on RFC 2461
  348  * Based on RFC 2462 (duplicate address detection)
  349  */
  350 void
  351 nd6_ns_output(struct ifnet *ifp, const struct in6_addr *daddr6,
  352     const struct in6_addr *taddr6,
  353     struct llinfo_nd6 *ln,      /* for source address determination */
  354     int dad                     /* duplicate address detection */)
  355 {
  356         struct mbuf *m;
  357         struct ip6_hdr *ip6;
  358         struct nd_neighbor_solicit *nd_ns;
  359         struct in6_addr *src, src_in;
  360         struct ip6_moptions im6o;
  361         int icmp6len;
  362         int maxlen;
  363         const void *mac;
  364         struct route ro;
  365 
  366         if (IN6_IS_ADDR_MULTICAST(taddr6))
  367                 return;
  368 
  369         memset(&ro, 0, sizeof(ro));
  370 
  371         /* estimate the size of message */
  372         maxlen = sizeof(*ip6) + sizeof(*nd_ns);
  373         maxlen += (sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7;
  374 #ifdef DIAGNOSTIC
  375         if (max_linkhdr + maxlen >= MCLBYTES) {
  376                 printf("nd6_ns_output: max_linkhdr + maxlen >= MCLBYTES "
  377                     "(%d + %d > %d)\n", max_linkhdr, maxlen, MCLBYTES);
  378                 panic("nd6_ns_output: insufficient MCLBYTES");
  379                 /* NOTREACHED */
  380         }
  381 #endif
  382 
  383         MGETHDR(m, M_DONTWAIT, MT_DATA);
  384         if (m && max_linkhdr + maxlen >= MHLEN) {
  385                 MCLGET(m, M_DONTWAIT);
  386                 if ((m->m_flags & M_EXT) == 0) {
  387                         m_free(m);
  388                         m = NULL;
  389                 }
  390         }
  391         if (m == NULL)
  392                 return;
  393         m->m_pkthdr.rcvif = NULL;
  394 
  395         if (daddr6 == NULL || IN6_IS_ADDR_MULTICAST(daddr6)) {
  396                 m->m_flags |= M_MCAST;
  397                 im6o.im6o_multicast_ifp = ifp;
  398                 im6o.im6o_multicast_hlim = 255;
  399                 im6o.im6o_multicast_loop = 0;
  400         }
  401 
  402         icmp6len = sizeof(*nd_ns);
  403         m->m_pkthdr.len = m->m_len = sizeof(*ip6) + icmp6len;
  404         m->m_data += max_linkhdr;       /* or MH_ALIGN() equivalent? */
  405 
  406         /* fill neighbor solicitation packet */
  407         ip6 = mtod(m, struct ip6_hdr *);
  408         ip6->ip6_flow = 0;
  409         ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
  410         ip6->ip6_vfc |= IPV6_VERSION;
  411         /* ip6->ip6_plen will be set later */
  412         ip6->ip6_nxt = IPPROTO_ICMPV6;
  413         ip6->ip6_hlim = 255;
  414         if (daddr6)
  415                 ip6->ip6_dst = *daddr6;
  416         else {
  417                 ip6->ip6_dst.s6_addr16[0] = IPV6_ADDR_INT16_MLL;
  418                 ip6->ip6_dst.s6_addr16[1] = 0;
  419                 ip6->ip6_dst.s6_addr32[1] = 0;
  420                 ip6->ip6_dst.s6_addr32[2] = IPV6_ADDR_INT32_ONE;
  421                 ip6->ip6_dst.s6_addr32[3] = taddr6->s6_addr32[3];
  422                 ip6->ip6_dst.s6_addr8[12] = 0xff;
  423                 if (in6_setscope(&ip6->ip6_dst, ifp, NULL) != 0)
  424                         goto bad;
  425         }
  426         if (!dad) {
  427                 /*
  428                  * RFC2461 7.2.2:
  429                  * "If the source address of the packet prompting the
  430                  * solicitation is the same as one of the addresses assigned
  431                  * to the outgoing interface, that address SHOULD be placed
  432                  * in the IP Source Address of the outgoing solicitation.
  433                  * Otherwise, any one of the addresses assigned to the
  434                  * interface should be used."
  435                  *
  436                  * We use the source address for the prompting packet
  437                  * (hsrc), if:
  438                  * - hsrc is given from the caller (by giving "ln"), and
  439                  * - hsrc belongs to the outgoing interface.
  440                  * Otherwise, we perform the source address selection as usual.
  441                  */
  442                 struct ip6_hdr *hip6;           /* hold ip6 */
  443                 struct in6_addr *hsrc = NULL;
  444 
  445                 if (ln && ln->ln_hold) {
  446                         /*
  447                          * assuming every packet in ln_hold has the same IP
  448                          * header
  449                          */
  450                         hip6 = mtod(ln->ln_hold, struct ip6_hdr *);
  451                         /* XXX pullup? */
  452                         if (sizeof(*hip6) < ln->ln_hold->m_len)
  453                                 hsrc = &hip6->ip6_src;
  454                         else
  455                                 hsrc = NULL;
  456                 }
  457                 if (hsrc && in6ifa_ifpwithaddr(ifp, hsrc))
  458                         src = hsrc;
  459                 else {
  460                         int error;
  461                         struct sockaddr_in6 dst_sa;
  462 
  463                         sockaddr_in6_init(&dst_sa, &ip6->ip6_dst, 0, 0, 0);
  464 
  465                         src = in6_selectsrc(&dst_sa, NULL,
  466                             NULL, &ro, NULL, NULL, &error);
  467                         if (src == NULL) {
  468                                 nd6log((LOG_DEBUG,
  469                                     "nd6_ns_output: source can't be "
  470                                     "determined: dst=%s, error=%d\n",
  471                                     ip6_sprintf(&dst_sa.sin6_addr), error));
  472                                 goto bad;
  473                         }
  474                 }
  475         } else {
  476                 /*
  477                  * Source address for DAD packet must always be IPv6
  478                  * unspecified address. (0::0)
  479                  * We actually don't have to 0-clear the address (we did it
  480                  * above), but we do so here explicitly to make the intention
  481                  * clearer.
  482                  */
  483                 memset(&src_in, 0, sizeof(src_in));
  484                 src = &src_in;
  485         }
  486         ip6->ip6_src = *src;
  487         nd_ns = (struct nd_neighbor_solicit *)(ip6 + 1);
  488         nd_ns->nd_ns_type = ND_NEIGHBOR_SOLICIT;
  489         nd_ns->nd_ns_code = 0;
  490         nd_ns->nd_ns_reserved = 0;
  491         nd_ns->nd_ns_target = *taddr6;
  492         in6_clearscope(&nd_ns->nd_ns_target); /* XXX */
  493 
  494         /*
  495          * Add source link-layer address option.
  496          *
  497          *                              spec            implementation
  498          *                              ---             ---
  499          * DAD packet                   MUST NOT        do not add the option
  500          * there's no link layer address:
  501          *                              impossible      do not add the option
  502          * there's link layer address:
  503          *      Multicast NS            MUST add one    add the option
  504          *      Unicast NS              SHOULD add one  add the option
  505          */
  506         if (!dad && (mac = nd6_ifptomac(ifp))) {
  507                 int optlen = sizeof(struct nd_opt_hdr) + ifp->if_addrlen;
  508                 struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)(nd_ns + 1);
  509                 /* 8 byte alignments... */
  510                 optlen = (optlen + 7) & ~7;
  511 
  512                 m->m_pkthdr.len += optlen;
  513                 m->m_len += optlen;
  514                 icmp6len += optlen;
  515                 memset((void *)nd_opt, 0, optlen);
  516                 nd_opt->nd_opt_type = ND_OPT_SOURCE_LINKADDR;
  517                 nd_opt->nd_opt_len = optlen >> 3;
  518                 memcpy((void *)(nd_opt + 1), mac, ifp->if_addrlen);
  519         }
  520 
  521         ip6->ip6_plen = htons((u_int16_t)icmp6len);
  522         nd_ns->nd_ns_cksum = 0;
  523         nd_ns->nd_ns_cksum =
  524             in6_cksum(m, IPPROTO_ICMPV6, sizeof(*ip6), icmp6len);
  525 
  526         ip6_output(m, NULL, &ro, dad ? IPV6_UNSPECSRC : 0, &im6o, NULL, NULL);
  527         icmp6_ifstat_inc(ifp, ifs6_out_msg);
  528         icmp6_ifstat_inc(ifp, ifs6_out_neighborsolicit);
  529         ICMP6_STATINC(ICMP6_STAT_OUTHIST + ND_NEIGHBOR_SOLICIT);
  530 
  531         rtcache_free(&ro);
  532         return;
  533 
  534   bad:
  535         rtcache_free(&ro);
  536         m_freem(m);
  537         return;
  538 }
  539 
  540 /*
  541  * Neighbor advertisement input handling.
  542  *
  543  * Based on RFC 2461
  544  * Based on RFC 2462 (duplicate address detection)
  545  *
  546  * the following items are not implemented yet:
  547  * - proxy advertisement delay rule (RFC2461 7.2.8, last paragraph, SHOULD)
  548  * - anycast advertisement delay rule (RFC2461 7.2.7, SHOULD)
  549  */
  550 void
  551 nd6_na_input(struct mbuf *m, int off, int icmp6len)
  552 {
  553         struct ifnet *ifp = m->m_pkthdr.rcvif;
  554         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
  555         struct nd_neighbor_advert *nd_na;
  556         struct in6_addr saddr6 = ip6->ip6_src;
  557         struct in6_addr daddr6 = ip6->ip6_dst;
  558         struct in6_addr taddr6;
  559         int flags;
  560         int is_router;
  561         int is_solicited;
  562         int is_override;
  563         char *lladdr = NULL;
  564         int lladdrlen = 0;
  565         struct ifaddr *ifa;
  566         struct llinfo_nd6 *ln;
  567         struct rtentry *rt;
  568         struct sockaddr_dl *sdl;
  569         union nd_opts ndopts;
  570 
  571         if (ip6->ip6_hlim != 255) {
  572                 nd6log((LOG_ERR,
  573                     "nd6_na_input: invalid hlim (%d) from %s to %s on %s\n",
  574                     ip6->ip6_hlim, ip6_sprintf(&ip6->ip6_src),
  575                     ip6_sprintf(&ip6->ip6_dst), if_name(ifp)));
  576                 goto bad;
  577         }
  578 
  579         IP6_EXTHDR_GET(nd_na, struct nd_neighbor_advert *, m, off, icmp6len);
  580         if (nd_na == NULL) {
  581                 ICMP6_STATINC(ICMP6_STAT_TOOSHORT);
  582                 return;
  583         }
  584 
  585         flags = nd_na->nd_na_flags_reserved;
  586         is_router = ((flags & ND_NA_FLAG_ROUTER) != 0);
  587         is_solicited = ((flags & ND_NA_FLAG_SOLICITED) != 0);
  588         is_override = ((flags & ND_NA_FLAG_OVERRIDE) != 0);
  589 
  590         taddr6 = nd_na->nd_na_target;
  591         if (in6_setscope(&taddr6, ifp, NULL))
  592                 return;         /* XXX: impossible */
  593 
  594         if (IN6_IS_ADDR_MULTICAST(&taddr6)) {
  595                 nd6log((LOG_ERR,
  596                     "nd6_na_input: invalid target address %s\n",
  597                     ip6_sprintf(&taddr6)));
  598                 goto bad;
  599         }
  600         if (is_solicited && IN6_IS_ADDR_MULTICAST(&daddr6)) {
  601                 nd6log((LOG_ERR,
  602                     "nd6_na_input: a solicited adv is multicasted\n"));
  603                 goto bad;
  604         }
  605 
  606         icmp6len -= sizeof(*nd_na);
  607         nd6_option_init(nd_na + 1, icmp6len, &ndopts);
  608         if (nd6_options(&ndopts) < 0) {
  609                 nd6log((LOG_INFO,
  610                     "nd6_na_input: invalid ND option, ignored\n"));
  611                 /* nd6_options have incremented stats */
  612                 goto freeit;
  613         }
  614 
  615         if (ndopts.nd_opts_tgt_lladdr) {
  616                 lladdr = (char *)(ndopts.nd_opts_tgt_lladdr + 1);
  617                 lladdrlen = ndopts.nd_opts_tgt_lladdr->nd_opt_len << 3;
  618         }
  619 
  620         ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
  621 
  622         /*
  623          * Target address matches one of my interface address.
  624          *
  625          * If my address is tentative, this means that there's somebody
  626          * already using the same address as mine.  This indicates DAD failure.
  627          * This is defined in RFC 2462.
  628          *
  629          * Otherwise, process as defined in RFC 2461.
  630          */
  631         if (ifa
  632          && (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_TENTATIVE)) {
  633                 nd6_dad_na_input(ifa);
  634                 goto freeit;
  635         }
  636 
  637         /* Just for safety, maybe unnecessary. */
  638         if (ifa) {
  639                 log(LOG_ERR,
  640                     "nd6_na_input: duplicate IP6 address %s\n",
  641                     ip6_sprintf(&taddr6));
  642                 goto freeit;
  643         }
  644         /*
  645          * Make sure the source address is from a neighbor's address.
  646          */
  647         if (in6ifa_ifplocaladdr(ifp, &saddr6) == NULL) {
  648                 nd6log((LOG_INFO, "nd6_ns_input: "
  649                     "ND packet from non-neighbor\n"));
  650                 goto bad;
  651         }
  652 
  653         if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
  654                 nd6log((LOG_INFO, "nd6_na_input: lladdrlen mismatch for %s "
  655                     "(if %d, NA packet %d)\n", ip6_sprintf(&taddr6),
  656                     ifp->if_addrlen, lladdrlen - 2));
  657                 goto bad;
  658         }
  659 
  660         /*
  661          * If no neighbor cache entry is found, NA SHOULD silently be
  662          * discarded.
  663          */
  664         rt = nd6_lookup(&taddr6, 0, ifp);
  665         if ((rt == NULL) ||
  666            ((ln = (struct llinfo_nd6 *)rt->rt_llinfo) == NULL) ||
  667            ((sdl = satosdl(rt->rt_gateway)) == NULL))
  668                 goto freeit;
  669 
  670         if (ln->ln_state == ND6_LLINFO_INCOMPLETE) {
  671                 /*
  672                  * If the link-layer has address, and no lladdr option came,
  673                  * discard the packet.
  674                  */
  675                 if (ifp->if_addrlen && !lladdr)
  676                         goto freeit;
  677 
  678                 /*
  679                  * Record link-layer address, and update the state.
  680                  */
  681                 (void)sockaddr_dl_setaddr(sdl, sdl->sdl_len, lladdr,
  682                     ifp->if_addrlen);
  683                 if (is_solicited) {
  684                         ln->ln_state = ND6_LLINFO_REACHABLE;
  685                         ln->ln_byhint = 0;
  686                         if (!ND6_LLINFO_PERMANENT(ln)) {
  687                                 nd6_llinfo_settimer(ln,
  688                                     (long)ND_IFINFO(rt->rt_ifp)->reachable * hz);
  689                         }
  690                 } else {
  691                         ln->ln_state = ND6_LLINFO_STALE;
  692                         nd6_llinfo_settimer(ln, (long)nd6_gctimer * hz);
  693                 }
  694                 if ((ln->ln_router = is_router) != 0) {
  695                         /*
  696                          * This means a router's state has changed from
  697                          * non-reachable to probably reachable, and might
  698                          * affect the status of associated prefixes..
  699                          */
  700                         pfxlist_onlink_check();
  701                 }
  702         } else {
  703                 int llchange;
  704 
  705                 /*
  706                  * Check if the link-layer address has changed or not.
  707                  */
  708                 if (lladdr == NULL)
  709                         llchange = 0;
  710                 else {
  711                         if (sdl->sdl_alen) {
  712                                 if (memcmp(lladdr, CLLADDR(sdl), ifp->if_addrlen))
  713                                         llchange = 1;
  714                                 else
  715                                         llchange = 0;
  716                         } else
  717                                 llchange = 1;
  718                 }
  719 
  720                 /*
  721                  * This is VERY complex.  Look at it with care.
  722                  *
  723                  * override solicit lladdr llchange     action
  724                  *                                      (L: record lladdr)
  725                  *
  726                  *      0       0       n       --      (2c)
  727                  *      0       0       y       n       (2b) L
  728                  *      0       0       y       y       (1)    REACHABLE->STALE
  729                  *      0       1       n       --      (2c)   *->REACHABLE
  730                  *      0       1       y       n       (2b) L *->REACHABLE
  731                  *      0       1       y       y       (1)    REACHABLE->STALE
  732                  *      1       0       n       --      (2a)
  733                  *      1       0       y       n       (2a) L
  734                  *      1       0       y       y       (2a) L *->STALE
  735                  *      1       1       n       --      (2a)   *->REACHABLE
  736                  *      1       1       y       n       (2a) L *->REACHABLE
  737                  *      1       1       y       y       (2a) L *->REACHABLE
  738                  */
  739                 if (!is_override && lladdr != NULL && llchange) { /* (1) */
  740                         /*
  741                          * If state is REACHABLE, make it STALE.
  742                          * no other updates should be done.
  743                          */
  744                         if (ln->ln_state == ND6_LLINFO_REACHABLE) {
  745                                 ln->ln_state = ND6_LLINFO_STALE;
  746                                 nd6_llinfo_settimer(ln, (long)nd6_gctimer * hz);
  747                         }
  748                         goto freeit;
  749                 } else if (is_override                             /* (2a) */
  750                     || (!is_override && lladdr != NULL && !llchange) /* (2b) */
  751                     || lladdr == NULL) {                           /* (2c) */
  752                         /*
  753                          * Update link-local address, if any.
  754                          */
  755                         if (lladdr != NULL) {
  756                                 (void)sockaddr_dl_setaddr(sdl, sdl->sdl_len,
  757                                     lladdr, ifp->if_addrlen);
  758                         }
  759 
  760                         /*
  761                          * If solicited, make the state REACHABLE.
  762                          * If not solicited and the link-layer address was
  763                          * changed, make it STALE.
  764                          */
  765                         if (is_solicited) {
  766                                 ln->ln_state = ND6_LLINFO_REACHABLE;
  767                                 ln->ln_byhint = 0;
  768                                 if (!ND6_LLINFO_PERMANENT(ln)) {
  769                                         nd6_llinfo_settimer(ln,
  770                                             (long)ND_IFINFO(ifp)->reachable * hz);
  771                                 }
  772                         } else {
  773                                 if (lladdr && llchange) {
  774                                         ln->ln_state = ND6_LLINFO_STALE;
  775                                         nd6_llinfo_settimer(ln,
  776                                             (long)nd6_gctimer * hz);
  777                                 }
  778                         }
  779                 }
  780 
  781                 if (ln->ln_router && !is_router) {
  782                         /*
  783                          * The peer dropped the router flag.
  784                          * Remove the sender from the Default Router List and
  785                          * update the Destination Cache entries.
  786                          */
  787                         struct nd_defrouter *dr;
  788                         const struct in6_addr *in6;
  789                         int s;
  790 
  791                         in6 = &satocsin6(rt_getkey(rt))->sin6_addr;
  792 
  793                         /*
  794                          * Lock to protect the default router list.
  795                          * XXX: this might be unnecessary, since this function
  796                          * is only called under the network software interrupt
  797                          * context.  However, we keep it just for safety.
  798                          */
  799                         s = splsoftnet();
  800                         dr = defrouter_lookup(in6, rt->rt_ifp);
  801                         if (dr)
  802                                 defrtrlist_del(dr);
  803                         else if (!ip6_forwarding) {
  804                                 /*
  805                                  * Even if the neighbor is not in the default
  806                                  * router list, the neighbor may be used
  807                                  * as a next hop for some destinations
  808                                  * (e.g. redirect case). So we must
  809                                  * call rt6_flush explicitly.
  810                                  */
  811                                 rt6_flush(&ip6->ip6_src, rt->rt_ifp);
  812                         }
  813                         splx(s);
  814                 }
  815                 ln->ln_router = is_router;
  816         }
  817         rt->rt_flags &= ~RTF_REJECT;
  818         ln->ln_asked = 0;
  819         nd6_llinfo_release_pkts(ln, ifp, rt);
  820 
  821  freeit:
  822         m_freem(m);
  823         return;
  824 
  825  bad:
  826         ICMP6_STATINC(ICMP6_STAT_BADNA);
  827         m_freem(m);
  828 }
  829 
  830 /*
  831  * Neighbor advertisement output handling.
  832  *
  833  * Based on RFC 2461
  834  *
  835  * the following items are not implemented yet:
  836  * - proxy advertisement delay rule (RFC2461 7.2.8, last paragraph, SHOULD)
  837  * - anycast advertisement delay rule (RFC2461 7.2.7, SHOULD)
  838  */
  839 void
  840 nd6_na_output(
  841         struct ifnet *ifp,
  842         const struct in6_addr *daddr6_0,
  843         const struct in6_addr *taddr6,
  844         u_long flags,
  845         int tlladdr,            /* 1 if include target link-layer address */
  846         const struct sockaddr *sdl0)    /* sockaddr_dl (= proxy NA) or NULL */
  847 {
  848         struct mbuf *m;
  849         struct ip6_hdr *ip6;
  850         struct nd_neighbor_advert *nd_na;
  851         struct ip6_moptions im6o;
  852         struct sockaddr *dst;
  853         union {
  854                 struct sockaddr         dst;
  855                 struct sockaddr_in6     dst6;
  856         } u;
  857         struct in6_addr *src, daddr6;
  858         int icmp6len, maxlen, error;
  859         const void *mac;
  860         struct route ro;
  861 
  862         mac = NULL;
  863         memset(&ro, 0, sizeof(ro));
  864 
  865         daddr6 = *daddr6_0;     /* make a local copy for modification */
  866 
  867         /* estimate the size of message */
  868         maxlen = sizeof(*ip6) + sizeof(*nd_na);
  869         maxlen += (sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7;
  870 #ifdef DIAGNOSTIC
  871         if (max_linkhdr + maxlen >= MCLBYTES) {
  872                 printf("nd6_na_output: max_linkhdr + maxlen >= MCLBYTES "
  873                     "(%d + %d > %d)\n", max_linkhdr, maxlen, MCLBYTES);
  874                 panic("nd6_na_output: insufficient MCLBYTES");
  875                 /* NOTREACHED */
  876         }
  877 #endif
  878 
  879         MGETHDR(m, M_DONTWAIT, MT_DATA);
  880         if (m && max_linkhdr + maxlen >= MHLEN) {
  881                 MCLGET(m, M_DONTWAIT);
  882                 if ((m->m_flags & M_EXT) == 0) {
  883                         m_free(m);
  884                         m = NULL;
  885                 }
  886         }
  887         if (m == NULL)
  888                 return;
  889         m->m_pkthdr.rcvif = NULL;
  890 
  891         if (IN6_IS_ADDR_MULTICAST(&daddr6)) {
  892                 m->m_flags |= M_MCAST;
  893                 im6o.im6o_multicast_ifp = ifp;
  894                 im6o.im6o_multicast_hlim = 255;
  895                 im6o.im6o_multicast_loop = 0;
  896         }
  897 
  898         icmp6len = sizeof(*nd_na);
  899         m->m_pkthdr.len = m->m_len = sizeof(struct ip6_hdr) + icmp6len;
  900         m->m_data += max_linkhdr;       /* or MH_ALIGN() equivalent? */
  901 
  902         /* fill neighbor advertisement packet */
  903         ip6 = mtod(m, struct ip6_hdr *);
  904         ip6->ip6_flow = 0;
  905         ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
  906         ip6->ip6_vfc |= IPV6_VERSION;
  907         ip6->ip6_nxt = IPPROTO_ICMPV6;
  908         ip6->ip6_hlim = 255;
  909         if (IN6_IS_ADDR_UNSPECIFIED(&daddr6)) {
  910                 /* reply to DAD */
  911                 daddr6.s6_addr16[0] = IPV6_ADDR_INT16_MLL;
  912                 daddr6.s6_addr16[1] = 0;
  913                 daddr6.s6_addr32[1] = 0;
  914                 daddr6.s6_addr32[2] = 0;
  915                 daddr6.s6_addr32[3] = IPV6_ADDR_INT32_ONE;
  916                 if (in6_setscope(&daddr6, ifp, NULL))
  917                         goto bad;
  918 
  919                 flags &= ~ND_NA_FLAG_SOLICITED;
  920         }
  921         ip6->ip6_dst = daddr6;
  922         sockaddr_in6_init(&u.dst6, &daddr6, 0, 0, 0);
  923         dst = &u.dst;
  924         rtcache_setdst(&ro, dst);
  925 
  926         /*
  927          * Select a source whose scope is the same as that of the dest.
  928          */
  929         src = in6_selectsrc(satosin6(dst), NULL, NULL, &ro, NULL, NULL, &error);
  930         if (src == NULL) {
  931                 nd6log((LOG_DEBUG, "nd6_na_output: source can't be "
  932                     "determined: dst=%s, error=%d\n",
  933                     ip6_sprintf(&satocsin6(dst)->sin6_addr), error));
  934                 goto bad;
  935         }
  936         ip6->ip6_src = *src;
  937         nd_na = (struct nd_neighbor_advert *)(ip6 + 1);
  938         nd_na->nd_na_type = ND_NEIGHBOR_ADVERT;
  939         nd_na->nd_na_code = 0;
  940         nd_na->nd_na_target = *taddr6;
  941         in6_clearscope(&nd_na->nd_na_target); /* XXX */
  942 
  943         /*
  944          * "tlladdr" indicates NS's condition for adding tlladdr or not.
  945          * see nd6_ns_input() for details.
  946          * Basically, if NS packet is sent to unicast/anycast addr,
  947          * target lladdr option SHOULD NOT be included.
  948          */
  949         if (tlladdr) {
  950                 /*
  951                  * sdl0 != NULL indicates proxy NA.  If we do proxy, use
  952                  * lladdr in sdl0.  If we are not proxying (sending NA for
  953                  * my address) use lladdr configured for the interface.
  954                  */
  955                 if (sdl0 == NULL)
  956                         mac = nd6_ifptomac(ifp);
  957                 else if (sdl0->sa_family == AF_LINK) {
  958                         const struct sockaddr_dl *sdl;
  959                         sdl = satocsdl(sdl0);
  960                         if (sdl->sdl_alen == ifp->if_addrlen)
  961                                 mac = CLLADDR(sdl);
  962                 }
  963         }
  964         if (tlladdr && mac) {
  965                 int optlen = sizeof(struct nd_opt_hdr) + ifp->if_addrlen;
  966                 struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)(nd_na + 1);
  967 
  968                 /* roundup to 8 bytes alignment! */
  969                 optlen = (optlen + 7) & ~7;
  970 
  971                 m->m_pkthdr.len += optlen;
  972                 m->m_len += optlen;
  973                 icmp6len += optlen;
  974                 memset((void *)nd_opt, 0, optlen);
  975                 nd_opt->nd_opt_type = ND_OPT_TARGET_LINKADDR;
  976                 nd_opt->nd_opt_len = optlen >> 3;
  977                 memcpy((void *)(nd_opt + 1), mac, ifp->if_addrlen);
  978         } else
  979                 flags &= ~ND_NA_FLAG_OVERRIDE;
  980 
  981         ip6->ip6_plen = htons((u_int16_t)icmp6len);
  982         nd_na->nd_na_flags_reserved = flags;
  983         nd_na->nd_na_cksum = 0;
  984         nd_na->nd_na_cksum =
  985             in6_cksum(m, IPPROTO_ICMPV6, sizeof(struct ip6_hdr), icmp6len);
  986 
  987         ip6_output(m, NULL, NULL, 0, &im6o, NULL, NULL);
  988 
  989         icmp6_ifstat_inc(ifp, ifs6_out_msg);
  990         icmp6_ifstat_inc(ifp, ifs6_out_neighboradvert);
  991         ICMP6_STATINC(ICMP6_STAT_OUTHIST + ND_NEIGHBOR_ADVERT);
  992 
  993         rtcache_free(&ro);
  994         return;
  995 
  996   bad:
  997         rtcache_free(&ro);
  998         m_freem(m);
  999         return;
 1000 }
 1001 
 1002 const void *
 1003 nd6_ifptomac(const struct ifnet *ifp)
 1004 {
 1005         switch (ifp->if_type) {
 1006         case IFT_ARCNET:
 1007         case IFT_ETHER:
 1008         case IFT_FDDI:
 1009         case IFT_IEEE1394:
 1010         case IFT_PROPVIRTUAL:
 1011         case IFT_CARP:
 1012         case IFT_L2VLAN:
 1013         case IFT_IEEE80211:
 1014                 return CLLADDR(ifp->if_sadl);
 1015         default:
 1016                 return NULL;
 1017         }
 1018 }
 1019 
 1020 TAILQ_HEAD(dadq_head, dadq);
 1021 struct dadq {
 1022         TAILQ_ENTRY(dadq) dad_list;
 1023         struct ifaddr *dad_ifa;
 1024         int dad_count;          /* max NS to send */
 1025         int dad_ns_tcount;      /* # of trials to send NS */
 1026         int dad_ns_ocount;      /* NS sent so far */
 1027         int dad_ns_icount;
 1028         int dad_na_icount;
 1029         struct callout dad_timer_ch;
 1030 };
 1031 
 1032 static struct dadq_head dadq;
 1033 static int dad_init = 0;
 1034 
 1035 static struct dadq *
 1036 nd6_dad_find(struct ifaddr *ifa)
 1037 {
 1038         struct dadq *dp;
 1039 
 1040         TAILQ_FOREACH(dp, &dadq, dad_list) {
 1041                 if (dp->dad_ifa == ifa)
 1042                         return dp;
 1043         }
 1044         return NULL;
 1045 }
 1046 
 1047 static void
 1048 nd6_dad_starttimer(struct dadq *dp, int ticks)
 1049 {
 1050 
 1051         callout_reset(&dp->dad_timer_ch, ticks,
 1052             (void (*)(void *))nd6_dad_timer, (void *)dp->dad_ifa);
 1053 }
 1054 
 1055 static void
 1056 nd6_dad_stoptimer(struct dadq *dp)
 1057 {
 1058 
 1059         callout_stop(&dp->dad_timer_ch);
 1060 }
 1061 
 1062 /*
 1063  * Start Duplicate Address Detection (DAD) for specified interface address.
 1064  *
 1065  * xtick: minimum delay ticks for IFF_UP event
 1066  */
 1067 void
 1068 nd6_dad_start(struct ifaddr *ifa, int xtick)
 1069 {
 1070         struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
 1071         struct dadq *dp;
 1072 
 1073         if (!dad_init) {
 1074                 TAILQ_INIT(&dadq);
 1075                 dad_init++;
 1076         }
 1077 
 1078         /*
 1079          * If we don't need DAD, don't do it.
 1080          * There are several cases:
 1081          * - DAD is disabled (ip6_dad_count == 0)
 1082          * - the interface address is anycast
 1083          */
 1084         if (!(ia->ia6_flags & IN6_IFF_TENTATIVE)) {
 1085                 log(LOG_DEBUG,
 1086                         "nd6_dad_start: called with non-tentative address "
 1087                         "%s(%s)\n",
 1088                         ip6_sprintf(&ia->ia_addr.sin6_addr),
 1089                         ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
 1090                 return;
 1091         }
 1092         if (ia->ia6_flags & IN6_IFF_ANYCAST) {
 1093                 ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
 1094                 return;
 1095         }
 1096         if (!ip6_dad_count) {
 1097                 ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
 1098                 return;
 1099         }
 1100         if (ifa->ifa_ifp == NULL)
 1101                 panic("nd6_dad_start: ifa->ifa_ifp == NULL");
 1102         if (!(ifa->ifa_ifp->if_flags & IFF_UP))
 1103                 return;
 1104         if (nd6_dad_find(ifa) != NULL) {
 1105                 /* DAD already in progress */
 1106                 return;
 1107         }
 1108 
 1109         dp = malloc(sizeof(*dp), M_IP6NDP, M_NOWAIT);
 1110         if (dp == NULL) {
 1111                 log(LOG_ERR, "nd6_dad_start: memory allocation failed for "
 1112                         "%s(%s)\n",
 1113                         ip6_sprintf(&ia->ia_addr.sin6_addr),
 1114                         ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
 1115                 return;
 1116         }
 1117         memset(dp, 0, sizeof(*dp));
 1118         callout_init(&dp->dad_timer_ch, CALLOUT_MPSAFE);
 1119         TAILQ_INSERT_TAIL(&dadq, (struct dadq *)dp, dad_list);
 1120 
 1121         nd6log((LOG_DEBUG, "%s: starting DAD for %s\n", if_name(ifa->ifa_ifp),
 1122             ip6_sprintf(&ia->ia_addr.sin6_addr)));
 1123 
 1124         /*
 1125          * Send NS packet for DAD, ip6_dad_count times.
 1126          * Note that we must delay the first transmission, if this is the
 1127          * first packet to be sent from the interface after interface
 1128          * (re)initialization.
 1129          */
 1130         dp->dad_ifa = ifa;
 1131         IFAREF(ifa);    /* just for safety */
 1132         dp->dad_count = ip6_dad_count;
 1133         dp->dad_ns_icount = dp->dad_na_icount = 0;
 1134         dp->dad_ns_ocount = dp->dad_ns_tcount = 0;
 1135         if (xtick == 0) {
 1136                 nd6_dad_ns_output(dp, ifa);
 1137                 nd6_dad_starttimer(dp,
 1138                     (long)ND_IFINFO(ifa->ifa_ifp)->retrans * hz / 1000);
 1139         } else
 1140                 nd6_dad_starttimer(dp, xtick);
 1141 }
 1142 
 1143 /*
 1144  * terminate DAD unconditionally.  used for address removals.
 1145  */
 1146 void
 1147 nd6_dad_stop(struct ifaddr *ifa)
 1148 {
 1149         struct dadq *dp;
 1150 
 1151         if (!dad_init)
 1152                 return;
 1153         dp = nd6_dad_find(ifa);
 1154         if (dp == NULL) {
 1155                 /* DAD wasn't started yet */
 1156                 return;
 1157         }
 1158 
 1159         nd6_dad_stoptimer(dp);
 1160 
 1161         TAILQ_REMOVE(&dadq, dp, dad_list);
 1162         free(dp, M_IP6NDP);
 1163         dp = NULL;
 1164         IFAFREE(ifa);
 1165 }
 1166 
 1167 static void
 1168 nd6_dad_timer(struct ifaddr *ifa)
 1169 {
 1170         struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
 1171         struct dadq *dp;
 1172 
 1173         mutex_enter(softnet_lock);
 1174         KERNEL_LOCK(1, NULL);
 1175 
 1176         /* Sanity check */
 1177         if (ia == NULL) {
 1178                 log(LOG_ERR, "nd6_dad_timer: called with null parameter\n");
 1179                 goto done;
 1180         }
 1181         dp = nd6_dad_find(ifa);
 1182         if (dp == NULL) {
 1183                 log(LOG_ERR, "nd6_dad_timer: DAD structure not found\n");
 1184                 goto done;
 1185         }
 1186         if (ia->ia6_flags & IN6_IFF_DUPLICATED) {
 1187                 log(LOG_ERR, "nd6_dad_timer: called with duplicate address "
 1188                         "%s(%s)\n",
 1189                         ip6_sprintf(&ia->ia_addr.sin6_addr),
 1190                         ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
 1191                 goto done;
 1192         }
 1193         if ((ia->ia6_flags & IN6_IFF_TENTATIVE) == 0) {
 1194                 log(LOG_ERR, "nd6_dad_timer: called with non-tentative address "
 1195                         "%s(%s)\n",
 1196                         ip6_sprintf(&ia->ia_addr.sin6_addr),
 1197                         ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
 1198                 goto done;
 1199         }
 1200 
 1201         /* timeouted with IFF_{RUNNING,UP} check */
 1202         if (dp->dad_ns_tcount > dad_maxtry) {
 1203                 nd6log((LOG_INFO, "%s: could not run DAD, driver problem?\n",
 1204                         if_name(ifa->ifa_ifp)));
 1205 
 1206                 TAILQ_REMOVE(&dadq, dp, dad_list);
 1207                 free(dp, M_IP6NDP);
 1208                 dp = NULL;
 1209                 IFAFREE(ifa);
 1210                 goto done;
 1211         }
 1212 
 1213         /* Need more checks? */
 1214         if (dp->dad_ns_ocount < dp->dad_count) {
 1215                 /*
 1216                  * We have more NS to go.  Send NS packet for DAD.
 1217                  */
 1218                 nd6_dad_ns_output(dp, ifa);
 1219                 nd6_dad_starttimer(dp,
 1220                     (long)ND_IFINFO(ifa->ifa_ifp)->retrans * hz / 1000);
 1221         } else {
 1222                 /*
 1223                  * We have transmitted sufficient number of DAD packets.
 1224                  * See what we've got.
 1225                  */
 1226                 int duplicate;
 1227 
 1228                 duplicate = 0;
 1229 
 1230                 if (dp->dad_na_icount) {
 1231                         /*
 1232                          * the check is in nd6_dad_na_input(),
 1233                          * but just in case
 1234                          */
 1235                         duplicate++;
 1236                 }
 1237 
 1238                 if (dp->dad_ns_icount) {
 1239                         /* We've seen NS, means DAD has failed. */
 1240                         duplicate++;
 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                          * No duplicate 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, dp, dad_list);
 1260                         free(dp, M_IP6NDP);
 1261                         dp = NULL;
 1262                         IFAFREE(ifa);
 1263                 }
 1264         }
 1265 
 1266 done:
 1267         KERNEL_UNLOCK_ONE(NULL);
 1268         mutex_exit(softnet_lock);
 1269 }
 1270 
 1271 void
 1272 nd6_dad_duplicated(struct ifaddr *ifa)
 1273 {
 1274         struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
 1275         struct ifnet *ifp;
 1276         struct dadq *dp;
 1277 
 1278         dp = nd6_dad_find(ifa);
 1279         if (dp == NULL) {
 1280                 log(LOG_ERR, "nd6_dad_duplicated: DAD structure not found\n");
 1281                 return;
 1282         }
 1283 
 1284         ifp = ifa->ifa_ifp;
 1285         log(LOG_ERR, "%s: DAD detected duplicate IPv6 address %s: "
 1286             "NS in/out=%d/%d, NA in=%d\n",
 1287             if_name(ifp), ip6_sprintf(&ia->ia_addr.sin6_addr),
 1288             dp->dad_ns_icount, dp->dad_ns_ocount, dp->dad_na_icount);
 1289 
 1290         ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
 1291         ia->ia6_flags |= IN6_IFF_DUPLICATED;
 1292 
 1293         /* We are done with DAD, with duplicated address found. (failure) */
 1294         nd6_dad_stoptimer(dp);
 1295 
 1296         log(LOG_ERR, "%s: DAD complete for %s - duplicate found\n",
 1297             if_name(ifp), ip6_sprintf(&ia->ia_addr.sin6_addr));
 1298         log(LOG_ERR, "%s: manual intervention required\n",
 1299             if_name(ifp));
 1300 
 1301         /*
 1302          * If the address is a link-local address formed from an interface
 1303          * identifier based on the hardware address which is supposed to be
 1304          * uniquely assigned (e.g., EUI-64 for an Ethernet interface), IP
 1305          * operation on the interface SHOULD be disabled.
 1306          * [rfc2462bis-03 Section 5.4.5]
 1307          */
 1308         if (IN6_IS_ADDR_LINKLOCAL(&ia->ia_addr.sin6_addr)) {
 1309                 struct in6_addr in6;
 1310 
 1311                 /*
 1312                  * To avoid over-reaction, we only apply this logic when we are
 1313                  * very sure that hardware addresses are supposed to be unique.
 1314                  */
 1315                 switch (ifp->if_type) {
 1316                 case IFT_ETHER:
 1317                 case IFT_FDDI:
 1318                 case IFT_ATM:
 1319                 case IFT_IEEE1394:
 1320 #ifdef IFT_IEEE80211
 1321                 case IFT_IEEE80211:
 1322 #endif
 1323                         in6 = ia->ia_addr.sin6_addr;
 1324                         if (in6_get_hw_ifid(ifp, &in6) == 0 &&
 1325                             IN6_ARE_ADDR_EQUAL(&ia->ia_addr.sin6_addr, &in6)) {
 1326                                 ND_IFINFO(ifp)->flags |= ND6_IFF_IFDISABLED;
 1327                                 log(LOG_ERR, "%s: possible hardware address "
 1328                                     "duplication detected, disable IPv6\n",
 1329                                     if_name(ifp));
 1330                         }
 1331                         break;
 1332                 }
 1333         }
 1334 
 1335         TAILQ_REMOVE(&dadq, dp, dad_list);
 1336         free(dp, M_IP6NDP);
 1337         dp = NULL;
 1338         IFAFREE(ifa);
 1339 }
 1340 
 1341 static void
 1342 nd6_dad_ns_output(struct dadq *dp, struct ifaddr *ifa)
 1343 {
 1344         struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
 1345         struct ifnet *ifp = ifa->ifa_ifp;
 1346 
 1347         dp->dad_ns_tcount++;
 1348         if ((ifp->if_flags & IFF_UP) == 0) {
 1349 #if 0
 1350                 printf("%s: interface down?\n", if_name(ifp));
 1351 #endif
 1352                 return;
 1353         }
 1354         if ((ifp->if_flags & IFF_RUNNING) == 0) {
 1355 #if 0
 1356                 printf("%s: interface not running?\n", if_name(ifp));
 1357 #endif
 1358                 return;
 1359         }
 1360 
 1361         dp->dad_ns_tcount = 0;
 1362         dp->dad_ns_ocount++;
 1363         nd6_ns_output(ifp, NULL, &ia->ia_addr.sin6_addr, NULL, 1);
 1364 }
 1365 
 1366 static void
 1367 nd6_dad_ns_input(struct ifaddr *ifa)
 1368 {
 1369         struct in6_ifaddr *ia;
 1370         const struct in6_addr *taddr6;
 1371         struct dadq *dp;
 1372         int duplicate;
 1373 
 1374         if (ifa == NULL)
 1375                 panic("ifa == NULL in nd6_dad_ns_input");
 1376 
 1377         ia = (struct in6_ifaddr *)ifa;
 1378         taddr6 = &ia->ia_addr.sin6_addr;
 1379         duplicate = 0;
 1380         dp = nd6_dad_find(ifa);
 1381 
 1382         /* Quickhack - completely ignore DAD NS packets */
 1383         if (dad_ignore_ns) {
 1384                 nd6log((LOG_INFO,
 1385                     "nd6_dad_ns_input: ignoring DAD NS packet for "
 1386                     "address %s(%s)\n", ip6_sprintf(taddr6),
 1387                     if_name(ifa->ifa_ifp)));
 1388                 return;
 1389         }
 1390 
 1391         /*
 1392          * if I'm yet to start DAD, someone else started using this address
 1393          * first.  I have a duplicate and you win.
 1394          */
 1395         if (dp == NULL || dp->dad_ns_ocount == 0)
 1396                 duplicate++;
 1397 
 1398         /* XXX more checks for loopback situation - see nd6_dad_timer too */
 1399 
 1400         if (duplicate) {
 1401                 dp = NULL;      /* will be freed in nd6_dad_duplicated() */
 1402                 nd6_dad_duplicated(ifa);
 1403         } else {
 1404                 /*
 1405                  * not sure if I got a duplicate.
 1406                  * increment ns count and see what happens.
 1407                  */
 1408                 if (dp)
 1409                         dp->dad_ns_icount++;
 1410         }
 1411 }
 1412 
 1413 static void
 1414 nd6_dad_na_input(struct ifaddr *ifa)
 1415 {
 1416         struct dadq *dp;
 1417 
 1418         if (ifa == NULL)
 1419                 panic("ifa == NULL in nd6_dad_na_input");
 1420 
 1421         dp = nd6_dad_find(ifa);
 1422         if (dp)
 1423                 dp->dad_na_icount++;
 1424 
 1425         /* remove the address. */
 1426         nd6_dad_duplicated(ifa);
 1427 }

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