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/10.1/sys/netinet6/nd6_nbr.c 273188 2014-10-16 22:00:24Z hrs $");
   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 static VNET_DEFINE(int, dad_ignore_ns) = 0;     /* ignore NS in DAD
   92                                                    - specwise incorrect */
   93 static VNET_DEFINE(int, dad_maxtry) = 15;       /* max # of *tries* to
   94                                                    transmit DAD packet */
   95 #define V_dad_ignore_ns                 VNET(dad_ignore_ns)
   96 #define V_dad_maxtry                    VNET(dad_maxtry)
   97 
   98 /*
   99  * Input a Neighbor Solicitation Message.
  100  *
  101  * Based on RFC 2461
  102  * Based on RFC 2462 (duplicate address detection)
  103  */
  104 void
  105 nd6_ns_input(struct mbuf *m, int off, int icmp6len)
  106 {
  107         struct ifnet *ifp = m->m_pkthdr.rcvif;
  108         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
  109         struct nd_neighbor_solicit *nd_ns;
  110         struct in6_addr saddr6 = ip6->ip6_src;
  111         struct in6_addr daddr6 = ip6->ip6_dst;
  112         struct in6_addr taddr6;
  113         struct in6_addr myaddr6;
  114         char *lladdr = NULL;
  115         struct ifaddr *ifa = NULL;
  116         int lladdrlen = 0;
  117         int anycast = 0, proxy = 0, tentative = 0;
  118         int tlladdr;
  119         int rflag;
  120         union nd_opts ndopts;
  121         struct sockaddr_dl proxydl;
  122         char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
  123 
  124         rflag = (V_ip6_forwarding) ? ND_NA_FLAG_ROUTER : 0;
  125         if (ND_IFINFO(ifp)->flags & ND6_IFF_ACCEPT_RTADV && V_ip6_norbit_raif)
  126                 rflag = 0;
  127 #ifndef PULLDOWN_TEST
  128         IP6_EXTHDR_CHECK(m, off, icmp6len,);
  129         nd_ns = (struct nd_neighbor_solicit *)((caddr_t)ip6 + off);
  130 #else
  131         IP6_EXTHDR_GET(nd_ns, struct nd_neighbor_solicit *, m, off, icmp6len);
  132         if (nd_ns == NULL) {
  133                 ICMP6STAT_INC(icp6s_tooshort);
  134                 return;
  135         }
  136 #endif
  137         ip6 = mtod(m, struct ip6_hdr *); /* adjust pointer for safety */
  138         taddr6 = nd_ns->nd_ns_target;
  139         if (in6_setscope(&taddr6, ifp, NULL) != 0)
  140                 goto bad;
  141 
  142         if (ip6->ip6_hlim != 255) {
  143                 nd6log((LOG_ERR,
  144                     "nd6_ns_input: invalid hlim (%d) from %s to %s on %s\n",
  145                     ip6->ip6_hlim, ip6_sprintf(ip6bufs, &ip6->ip6_src),
  146                     ip6_sprintf(ip6bufd, &ip6->ip6_dst), if_name(ifp)));
  147                 goto bad;
  148         }
  149 
  150         if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) {
  151                 /* dst has to be a solicited node multicast address. */
  152                 if (daddr6.s6_addr16[0] == IPV6_ADDR_INT16_MLL &&
  153                     /* don't check ifindex portion */
  154                     daddr6.s6_addr32[1] == 0 &&
  155                     daddr6.s6_addr32[2] == IPV6_ADDR_INT32_ONE &&
  156                     daddr6.s6_addr8[12] == 0xff) {
  157                         ; /* good */
  158                 } else {
  159                         nd6log((LOG_INFO, "nd6_ns_input: bad DAD packet "
  160                             "(wrong ip6 dst)\n"));
  161                         goto bad;
  162                 }
  163         } else if (!V_nd6_onlink_ns_rfc4861) {
  164                 struct sockaddr_in6 src_sa6;
  165 
  166                 /*
  167                  * According to recent IETF discussions, it is not a good idea
  168                  * to accept a NS from an address which would not be deemed
  169                  * to be a neighbor otherwise.  This point is expected to be
  170                  * clarified in future revisions of the specification.
  171                  */
  172                 bzero(&src_sa6, sizeof(src_sa6));
  173                 src_sa6.sin6_family = AF_INET6;
  174                 src_sa6.sin6_len = sizeof(src_sa6);
  175                 src_sa6.sin6_addr = saddr6;
  176                 if (nd6_is_addr_neighbor(&src_sa6, ifp) == 0) {
  177                         nd6log((LOG_INFO, "nd6_ns_input: "
  178                                 "NS packet from non-neighbor\n"));
  179                         goto bad;
  180                 }
  181         }
  182 
  183         if (IN6_IS_ADDR_MULTICAST(&taddr6)) {
  184                 nd6log((LOG_INFO, "nd6_ns_input: bad NS target (multicast)\n"));
  185                 goto bad;
  186         }
  187 
  188         icmp6len -= sizeof(*nd_ns);
  189         nd6_option_init(nd_ns + 1, icmp6len, &ndopts);
  190         if (nd6_options(&ndopts) < 0) {
  191                 nd6log((LOG_INFO,
  192                     "nd6_ns_input: invalid ND option, ignored\n"));
  193                 /* nd6_options have incremented stats */
  194                 goto freeit;
  195         }
  196 
  197         if (ndopts.nd_opts_src_lladdr) {
  198                 lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1);
  199                 lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
  200         }
  201 
  202         if (IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src) && lladdr) {
  203                 nd6log((LOG_INFO, "nd6_ns_input: bad DAD packet "
  204                     "(link-layer address option)\n"));
  205                 goto bad;
  206         }
  207 
  208         /*
  209          * Attaching target link-layer address to the NA?
  210          * (RFC 2461 7.2.4)
  211          *
  212          * NS IP dst is unicast/anycast                 MUST NOT add
  213          * NS IP dst is solicited-node multicast        MUST add
  214          *
  215          * In implementation, we add target link-layer address by default.
  216          * We do not add one in MUST NOT cases.
  217          */
  218         if (!IN6_IS_ADDR_MULTICAST(&daddr6))
  219                 tlladdr = 0;
  220         else
  221                 tlladdr = 1;
  222 
  223         /*
  224          * Target address (taddr6) must be either:
  225          * (1) Valid unicast/anycast address for my receiving interface,
  226          * (2) Unicast address for which I'm offering proxy service, or
  227          * (3) "tentative" address on which DAD is being performed.
  228          */
  229         /* (1) and (3) check. */
  230         if (ifp->if_carp)
  231                 ifa = (*carp_iamatch6_p)(ifp, &taddr6);
  232         else
  233                 ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
  234 
  235         /* (2) check. */
  236         if (ifa == NULL) {
  237                 struct route_in6 ro;
  238                 int need_proxy;
  239 
  240                 bzero(&ro, sizeof(ro));
  241                 ro.ro_dst.sin6_len = sizeof(struct sockaddr_in6);
  242                 ro.ro_dst.sin6_family = AF_INET6;
  243                 ro.ro_dst.sin6_addr = taddr6;
  244 
  245                 /* Always use the default FIB. */
  246 #ifdef RADIX_MPATH
  247                 rtalloc_mpath_fib((struct route *)&ro, RTF_ANNOUNCE,
  248                     RT_DEFAULT_FIB);
  249 #else
  250                 in6_rtalloc(&ro, RT_DEFAULT_FIB);
  251 #endif
  252                 need_proxy = (ro.ro_rt &&
  253                     (ro.ro_rt->rt_flags & RTF_ANNOUNCE) != 0 &&
  254                     ro.ro_rt->rt_gateway->sa_family == AF_LINK);
  255                 if (ro.ro_rt != NULL) {
  256                         if (need_proxy)
  257                                 proxydl = *SDL(ro.ro_rt->rt_gateway);
  258                         RTFREE(ro.ro_rt);
  259                 }
  260                 if (need_proxy) {
  261                         /*
  262                          * proxy NDP for single entry
  263                          */
  264                         ifa = (struct ifaddr *)in6ifa_ifpforlinklocal(ifp,
  265                                 IN6_IFF_NOTREADY|IN6_IFF_ANYCAST);
  266                         if (ifa)
  267                                 proxy = 1;
  268                 }
  269         }
  270         if (ifa == NULL) {
  271                 /*
  272                  * We've got an NS packet, and we don't have that adddress
  273                  * assigned for us.  We MUST silently ignore it.
  274                  * See RFC2461 7.2.3.
  275                  */
  276                 goto freeit;
  277         }
  278         myaddr6 = *IFA_IN6(ifa);
  279         anycast = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_ANYCAST;
  280         tentative = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_TENTATIVE;
  281         if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_DUPLICATED)
  282                 goto freeit;
  283 
  284         if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
  285                 nd6log((LOG_INFO, "nd6_ns_input: lladdrlen mismatch for %s "
  286                     "(if %d, NS packet %d)\n",
  287                     ip6_sprintf(ip6bufs, &taddr6),
  288                     ifp->if_addrlen, lladdrlen - 2));
  289                 goto bad;
  290         }
  291 
  292         if (IN6_ARE_ADDR_EQUAL(&myaddr6, &saddr6)) {
  293                 nd6log((LOG_INFO, "nd6_ns_input: duplicate IP6 address %s\n",
  294                     ip6_sprintf(ip6bufs, &saddr6)));
  295                 goto freeit;
  296         }
  297 
  298         /*
  299          * We have neighbor solicitation packet, with target address equals to
  300          * one of my tentative address.
  301          *
  302          * src addr     how to process?
  303          * ---          ---
  304          * multicast    of course, invalid (rejected in ip6_input)
  305          * unicast      somebody is doing address resolution -> ignore
  306          * unspec       dup address detection
  307          *
  308          * The processing is defined in RFC 2462.
  309          */
  310         if (tentative) {
  311                 /*
  312                  * If source address is unspecified address, it is for
  313                  * duplicate address detection.
  314                  *
  315                  * If not, the packet is for addess resolution;
  316                  * silently ignore it.
  317                  */
  318                 if (IN6_IS_ADDR_UNSPECIFIED(&saddr6))
  319                         nd6_dad_ns_input(ifa);
  320 
  321                 goto freeit;
  322         }
  323 
  324         /*
  325          * If the source address is unspecified address, entries must not
  326          * be created or updated.
  327          * It looks that sender is performing DAD.  Output NA toward
  328          * all-node multicast address, to tell the sender that I'm using
  329          * the address.
  330          * S bit ("solicited") must be zero.
  331          */
  332         if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) {
  333                 struct in6_addr in6_all;
  334 
  335                 in6_all = in6addr_linklocal_allnodes;
  336                 if (in6_setscope(&in6_all, ifp, NULL) != 0)
  337                         goto bad;
  338                 nd6_na_output_fib(ifp, &in6_all, &taddr6,
  339                     ((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE) |
  340                     rflag, tlladdr, proxy ? (struct sockaddr *)&proxydl : NULL,
  341                     M_GETFIB(m));
  342                 goto freeit;
  343         }
  344 
  345         nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen,
  346             ND_NEIGHBOR_SOLICIT, 0);
  347 
  348         nd6_na_output_fib(ifp, &saddr6, &taddr6,
  349             ((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE) |
  350             rflag | ND_NA_FLAG_SOLICITED, tlladdr,
  351             proxy ? (struct sockaddr *)&proxydl : NULL, M_GETFIB(m));
  352  freeit:
  353         if (ifa != NULL)
  354                 ifa_free(ifa);
  355         m_freem(m);
  356         return;
  357 
  358  bad:
  359         nd6log((LOG_ERR, "nd6_ns_input: src=%s\n",
  360                 ip6_sprintf(ip6bufs, &saddr6)));
  361         nd6log((LOG_ERR, "nd6_ns_input: dst=%s\n",
  362                 ip6_sprintf(ip6bufs, &daddr6)));
  363         nd6log((LOG_ERR, "nd6_ns_input: tgt=%s\n",
  364                 ip6_sprintf(ip6bufs, &taddr6)));
  365         ICMP6STAT_INC(icp6s_badns);
  366         if (ifa != NULL)
  367                 ifa_free(ifa);
  368         m_freem(m);
  369 }
  370 
  371 /*
  372  * Output a Neighbor Solicitation Message. Caller specifies:
  373  *      - ICMP6 header source IP6 address
  374  *      - ND6 header target IP6 address
  375  *      - ND6 header source datalink address
  376  *
  377  * Based on RFC 2461
  378  * Based on RFC 2462 (duplicate address detection)
  379  *
  380  *   ln - for source address determination
  381  *  dad - duplicate address detection
  382  */
  383 void
  384 nd6_ns_output(struct ifnet *ifp, const struct in6_addr *daddr6, 
  385     const struct in6_addr *taddr6, struct llentry *ln, int dad)
  386 {
  387         struct mbuf *m;
  388         struct m_tag *mtag;
  389         struct ip6_hdr *ip6;
  390         struct nd_neighbor_solicit *nd_ns;
  391         struct ip6_moptions im6o;
  392         int icmp6len;
  393         int maxlen;
  394         caddr_t mac;
  395         struct route_in6 ro;
  396 
  397         if (IN6_IS_ADDR_MULTICAST(taddr6))
  398                 return;
  399 
  400         /* estimate the size of message */
  401         maxlen = sizeof(*ip6) + sizeof(*nd_ns);
  402         maxlen += (sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7;
  403         if (max_linkhdr + maxlen >= MCLBYTES) {
  404 #ifdef DIAGNOSTIC
  405                 printf("nd6_ns_output: max_linkhdr + maxlen >= MCLBYTES "
  406                     "(%d + %d > %d)\n", max_linkhdr, maxlen, MCLBYTES);
  407 #endif
  408                 return;
  409         }
  410 
  411         if (max_linkhdr + maxlen > MHLEN)
  412                 m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
  413         else
  414                 m = m_gethdr(M_NOWAIT, MT_DATA);
  415         if (m == NULL)
  416                 return;
  417 
  418         bzero(&ro, sizeof(ro));
  419 
  420         if (daddr6 == NULL || IN6_IS_ADDR_MULTICAST(daddr6)) {
  421                 m->m_flags |= M_MCAST;
  422                 im6o.im6o_multicast_ifp = ifp;
  423                 im6o.im6o_multicast_hlim = 255;
  424                 im6o.im6o_multicast_loop = 0;
  425         }
  426 
  427         icmp6len = sizeof(*nd_ns);
  428         m->m_pkthdr.len = m->m_len = sizeof(*ip6) + icmp6len;
  429         m->m_data += max_linkhdr;       /* or MH_ALIGN() equivalent? */
  430 
  431         /* fill neighbor solicitation packet */
  432         ip6 = mtod(m, struct ip6_hdr *);
  433         ip6->ip6_flow = 0;
  434         ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
  435         ip6->ip6_vfc |= IPV6_VERSION;
  436         /* ip6->ip6_plen will be set later */
  437         ip6->ip6_nxt = IPPROTO_ICMPV6;
  438         ip6->ip6_hlim = 255;
  439         if (daddr6)
  440                 ip6->ip6_dst = *daddr6;
  441         else {
  442                 ip6->ip6_dst.s6_addr16[0] = IPV6_ADDR_INT16_MLL;
  443                 ip6->ip6_dst.s6_addr16[1] = 0;
  444                 ip6->ip6_dst.s6_addr32[1] = 0;
  445                 ip6->ip6_dst.s6_addr32[2] = IPV6_ADDR_INT32_ONE;
  446                 ip6->ip6_dst.s6_addr32[3] = taddr6->s6_addr32[3];
  447                 ip6->ip6_dst.s6_addr8[12] = 0xff;
  448                 if (in6_setscope(&ip6->ip6_dst, ifp, NULL) != 0)
  449                         goto bad;
  450         }
  451         if (!dad) {
  452                 struct ifaddr *ifa;
  453 
  454                 /*
  455                  * RFC2461 7.2.2:
  456                  * "If the source address of the packet prompting the
  457                  * solicitation is the same as one of the addresses assigned
  458                  * to the outgoing interface, that address SHOULD be placed
  459                  * in the IP Source Address of the outgoing solicitation.
  460                  * Otherwise, any one of the addresses assigned to the
  461                  * interface should be used."
  462                  *
  463                  * We use the source address for the prompting packet
  464                  * (saddr6), if:
  465                  * - saddr6 is given from the caller (by giving "ln"), and
  466                  * - saddr6 belongs to the outgoing interface.
  467                  * Otherwise, we perform the source address selection as usual.
  468                  */
  469                 struct in6_addr *hsrc;
  470 
  471                 hsrc = NULL;
  472                 if (ln != NULL) {
  473                         LLE_RLOCK(ln);
  474                         if (ln->la_hold != NULL) {
  475                                 struct ip6_hdr *hip6;           /* hold ip6 */
  476 
  477                                 /*
  478                                  * assuming every packet in la_hold has the same IP
  479                                  * header
  480                                  */
  481                                 hip6 = mtod(ln->la_hold, struct ip6_hdr *);
  482                                 /* XXX pullup? */
  483                                 if (sizeof(*hip6) < ln->la_hold->m_len) {
  484                                         ip6->ip6_src = hip6->ip6_src;
  485                                         hsrc = &hip6->ip6_src;
  486                                 }
  487                         }
  488                         LLE_RUNLOCK(ln);
  489                 }
  490                 if (hsrc && (ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp,
  491                     hsrc)) != NULL) {
  492                         /* ip6_src set already. */
  493                         ifa_free(ifa);
  494                 } else {
  495                         int error;
  496                         struct sockaddr_in6 dst_sa;
  497                         struct in6_addr src_in;
  498                         struct ifnet *oifp;
  499 
  500                         bzero(&dst_sa, sizeof(dst_sa));
  501                         dst_sa.sin6_family = AF_INET6;
  502                         dst_sa.sin6_len = sizeof(dst_sa);
  503                         dst_sa.sin6_addr = ip6->ip6_dst;
  504 
  505                         oifp = ifp;
  506                         error = in6_selectsrc(&dst_sa, NULL,
  507                             NULL, &ro, NULL, &oifp, &src_in);
  508                         if (error) {
  509                                 char ip6buf[INET6_ADDRSTRLEN];
  510                                 nd6log((LOG_DEBUG,
  511                                     "nd6_ns_output: source can't be "
  512                                     "determined: dst=%s, error=%d\n",
  513                                     ip6_sprintf(ip6buf, &dst_sa.sin6_addr),
  514                                     error));
  515                                 goto bad;
  516                         }
  517                         ip6->ip6_src = src_in;
  518                 }
  519         } else {
  520                 /*
  521                  * Source address for DAD packet must always be IPv6
  522                  * unspecified address. (0::0)
  523                  * We actually don't have to 0-clear the address (we did it
  524                  * above), but we do so here explicitly to make the intention
  525                  * clearer.
  526                  */
  527                 bzero(&ip6->ip6_src, sizeof(ip6->ip6_src));
  528         }
  529         nd_ns = (struct nd_neighbor_solicit *)(ip6 + 1);
  530         nd_ns->nd_ns_type = ND_NEIGHBOR_SOLICIT;
  531         nd_ns->nd_ns_code = 0;
  532         nd_ns->nd_ns_reserved = 0;
  533         nd_ns->nd_ns_target = *taddr6;
  534         in6_clearscope(&nd_ns->nd_ns_target); /* XXX */
  535 
  536         /*
  537          * Add source link-layer address option.
  538          *
  539          *                              spec            implementation
  540          *                              ---             ---
  541          * DAD packet                   MUST NOT        do not add the option
  542          * there's no link layer address:
  543          *                              impossible      do not add the option
  544          * there's link layer address:
  545          *      Multicast NS            MUST add one    add the option
  546          *      Unicast NS              SHOULD add one  add the option
  547          */
  548         if (!dad && (mac = nd6_ifptomac(ifp))) {
  549                 int optlen = sizeof(struct nd_opt_hdr) + ifp->if_addrlen;
  550                 struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)(nd_ns + 1);
  551                 /* 8 byte alignments... */
  552                 optlen = (optlen + 7) & ~7;
  553 
  554                 m->m_pkthdr.len += optlen;
  555                 m->m_len += optlen;
  556                 icmp6len += optlen;
  557                 bzero((caddr_t)nd_opt, optlen);
  558                 nd_opt->nd_opt_type = ND_OPT_SOURCE_LINKADDR;
  559                 nd_opt->nd_opt_len = optlen >> 3;
  560                 bcopy(mac, (caddr_t)(nd_opt + 1), ifp->if_addrlen);
  561         }
  562 
  563         ip6->ip6_plen = htons((u_short)icmp6len);
  564         nd_ns->nd_ns_cksum = 0;
  565         nd_ns->nd_ns_cksum =
  566             in6_cksum(m, IPPROTO_ICMPV6, sizeof(*ip6), icmp6len);
  567 
  568         if (send_sendso_input_hook != NULL) {
  569                 mtag = m_tag_get(PACKET_TAG_ND_OUTGOING,
  570                         sizeof(unsigned short), M_NOWAIT);
  571                 if (mtag == NULL)
  572                         goto bad;
  573                 *(unsigned short *)(mtag + 1) = nd_ns->nd_ns_type;
  574                 m_tag_prepend(m, mtag);
  575         }
  576 
  577         ip6_output(m, NULL, &ro, dad ? IPV6_UNSPECSRC : 0, &im6o, NULL, NULL);
  578         icmp6_ifstat_inc(ifp, ifs6_out_msg);
  579         icmp6_ifstat_inc(ifp, ifs6_out_neighborsolicit);
  580         ICMP6STAT_INC(icp6s_outhist[ND_NEIGHBOR_SOLICIT]);
  581 
  582         /* We don't cache this route. */
  583         RO_RTFREE(&ro);
  584 
  585         return;
  586 
  587   bad:
  588         if (ro.ro_rt) {
  589                 RTFREE(ro.ro_rt);
  590         }
  591         m_freem(m);
  592         return;
  593 }
  594 
  595 /*
  596  * Neighbor advertisement input handling.
  597  *
  598  * Based on RFC 2461
  599  * Based on RFC 2462 (duplicate address detection)
  600  *
  601  * the following items are not implemented yet:
  602  * - proxy advertisement delay rule (RFC2461 7.2.8, last paragraph, SHOULD)
  603  * - anycast advertisement delay rule (RFC2461 7.2.7, SHOULD)
  604  */
  605 void
  606 nd6_na_input(struct mbuf *m, int off, int icmp6len)
  607 {
  608         struct ifnet *ifp = m->m_pkthdr.rcvif;
  609         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
  610         struct nd_neighbor_advert *nd_na;
  611         struct in6_addr daddr6 = ip6->ip6_dst;
  612         struct in6_addr taddr6;
  613         int flags;
  614         int is_router;
  615         int is_solicited;
  616         int is_override;
  617         char *lladdr = NULL;
  618         int lladdrlen = 0;
  619         int checklink = 0;
  620         struct ifaddr *ifa;
  621         struct llentry *ln = NULL;
  622         union nd_opts ndopts;
  623         struct mbuf *chain = NULL;
  624         struct m_tag *mtag;
  625         struct sockaddr_in6 sin6;
  626         char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
  627 
  628         if (ip6->ip6_hlim != 255) {
  629                 nd6log((LOG_ERR,
  630                     "nd6_na_input: invalid hlim (%d) from %s to %s on %s\n",
  631                     ip6->ip6_hlim, ip6_sprintf(ip6bufs, &ip6->ip6_src),
  632                     ip6_sprintf(ip6bufd, &ip6->ip6_dst), if_name(ifp)));
  633                 goto bad;
  634         }
  635 
  636 #ifndef PULLDOWN_TEST
  637         IP6_EXTHDR_CHECK(m, off, icmp6len,);
  638         nd_na = (struct nd_neighbor_advert *)((caddr_t)ip6 + off);
  639 #else
  640         IP6_EXTHDR_GET(nd_na, struct nd_neighbor_advert *, m, off, icmp6len);
  641         if (nd_na == NULL) {
  642                 ICMP6STAT_INC(icp6s_tooshort);
  643                 return;
  644         }
  645 #endif
  646 
  647         flags = nd_na->nd_na_flags_reserved;
  648         is_router = ((flags & ND_NA_FLAG_ROUTER) != 0);
  649         is_solicited = ((flags & ND_NA_FLAG_SOLICITED) != 0);
  650         is_override = ((flags & ND_NA_FLAG_OVERRIDE) != 0);
  651 
  652         taddr6 = nd_na->nd_na_target;
  653         if (in6_setscope(&taddr6, ifp, NULL))
  654                 goto bad;       /* XXX: impossible */
  655 
  656         if (IN6_IS_ADDR_MULTICAST(&taddr6)) {
  657                 nd6log((LOG_ERR,
  658                     "nd6_na_input: invalid target address %s\n",
  659                     ip6_sprintf(ip6bufs, &taddr6)));
  660                 goto bad;
  661         }
  662         if (IN6_IS_ADDR_MULTICAST(&daddr6))
  663                 if (is_solicited) {
  664                         nd6log((LOG_ERR,
  665                             "nd6_na_input: a solicited adv is multicasted\n"));
  666                         goto bad;
  667                 }
  668 
  669         icmp6len -= sizeof(*nd_na);
  670         nd6_option_init(nd_na + 1, icmp6len, &ndopts);
  671         if (nd6_options(&ndopts) < 0) {
  672                 nd6log((LOG_INFO,
  673                     "nd6_na_input: invalid ND option, ignored\n"));
  674                 /* nd6_options have incremented stats */
  675                 goto freeit;
  676         }
  677 
  678         if (ndopts.nd_opts_tgt_lladdr) {
  679                 lladdr = (char *)(ndopts.nd_opts_tgt_lladdr + 1);
  680                 lladdrlen = ndopts.nd_opts_tgt_lladdr->nd_opt_len << 3;
  681         }
  682 
  683         /*
  684          * This effectively disables the DAD check on a non-master CARP
  685          * address.
  686          */
  687         if (ifp->if_carp)
  688                 ifa = (*carp_iamatch6_p)(ifp, &taddr6);
  689         else
  690                 ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
  691 
  692         /*
  693          * Target address matches one of my interface address.
  694          *
  695          * If my address is tentative, this means that there's somebody
  696          * already using the same address as mine.  This indicates DAD failure.
  697          * This is defined in RFC 2462.
  698          *
  699          * Otherwise, process as defined in RFC 2461.
  700          */
  701         if (ifa
  702          && (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_TENTATIVE)) {
  703                 ifa_free(ifa);
  704                 nd6_dad_na_input(ifa);
  705                 goto freeit;
  706         }
  707 
  708         /* Just for safety, maybe unnecessary. */
  709         if (ifa) {
  710                 ifa_free(ifa);
  711                 log(LOG_ERR,
  712                     "nd6_na_input: duplicate IP6 address %s\n",
  713                     ip6_sprintf(ip6bufs, &taddr6));
  714                 goto freeit;
  715         }
  716 
  717         if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
  718                 nd6log((LOG_INFO, "nd6_na_input: lladdrlen mismatch for %s "
  719                     "(if %d, NA packet %d)\n", ip6_sprintf(ip6bufs, &taddr6),
  720                     ifp->if_addrlen, lladdrlen - 2));
  721                 goto bad;
  722         }
  723 
  724         /*
  725          * If no neighbor cache entry is found, NA SHOULD silently be
  726          * discarded.
  727          */
  728         IF_AFDATA_RLOCK(ifp);
  729         ln = nd6_lookup(&taddr6, LLE_EXCLUSIVE, ifp);
  730         IF_AFDATA_RUNLOCK(ifp);
  731         if (ln == NULL) {
  732                 goto freeit;
  733         }
  734 
  735         if (ln->ln_state == ND6_LLINFO_INCOMPLETE) {
  736                 /*
  737                  * If the link-layer has address, and no lladdr option came,
  738                  * discard the packet.
  739                  */
  740                 if (ifp->if_addrlen && lladdr == NULL) {
  741                         goto freeit;
  742                 }
  743 
  744                 /*
  745                  * Record link-layer address, and update the state.
  746                  */
  747                 bcopy(lladdr, &ln->ll_addr, ifp->if_addrlen);
  748                 ln->la_flags |= LLE_VALID;
  749                 EVENTHANDLER_INVOKE(lle_event, ln, LLENTRY_RESOLVED);
  750                 if (is_solicited) {
  751                         ln->ln_state = ND6_LLINFO_REACHABLE;
  752                         ln->ln_byhint = 0;
  753                         if (!ND6_LLINFO_PERMANENT(ln)) {
  754                                 nd6_llinfo_settimer_locked(ln,
  755                                     (long)ND_IFINFO(ln->lle_tbl->llt_ifp)->reachable * hz);
  756                         }
  757                 } else {
  758                         ln->ln_state = ND6_LLINFO_STALE;
  759                         nd6_llinfo_settimer_locked(ln, (long)V_nd6_gctimer * hz);
  760                 }
  761                 if ((ln->ln_router = is_router) != 0) {
  762                         /*
  763                          * This means a router's state has changed from
  764                          * non-reachable to probably reachable, and might
  765                          * affect the status of associated prefixes..
  766                          */
  767                         checklink = 1;
  768                 }
  769         } else {
  770                 int llchange;
  771 
  772                 /*
  773                  * Check if the link-layer address has changed or not.
  774                  */
  775                 if (lladdr == NULL)
  776                         llchange = 0;
  777                 else {
  778                         if (ln->la_flags & LLE_VALID) {
  779                                 if (bcmp(lladdr, &ln->ll_addr, ifp->if_addrlen))
  780                                         llchange = 1;
  781                                 else
  782                                         llchange = 0;
  783                         } else
  784                                 llchange = 1;
  785                 }
  786 
  787                 /*
  788                  * This is VERY complex.  Look at it with care.
  789                  *
  790                  * override solicit lladdr llchange     action
  791                  *                                      (L: record lladdr)
  792                  *
  793                  *      0       0       n       --      (2c)
  794                  *      0       0       y       n       (2b) L
  795                  *      0       0       y       y       (1)    REACHABLE->STALE
  796                  *      0       1       n       --      (2c)   *->REACHABLE
  797                  *      0       1       y       n       (2b) L *->REACHABLE
  798                  *      0       1       y       y       (1)    REACHABLE->STALE
  799                  *      1       0       n       --      (2a)
  800                  *      1       0       y       n       (2a) L
  801                  *      1       0       y       y       (2a) L *->STALE
  802                  *      1       1       n       --      (2a)   *->REACHABLE
  803                  *      1       1       y       n       (2a) L *->REACHABLE
  804                  *      1       1       y       y       (2a) L *->REACHABLE
  805                  */
  806                 if (!is_override && (lladdr != NULL && llchange)) {  /* (1) */
  807                         /*
  808                          * If state is REACHABLE, make it STALE.
  809                          * no other updates should be done.
  810                          */
  811                         if (ln->ln_state == ND6_LLINFO_REACHABLE) {
  812                                 ln->ln_state = ND6_LLINFO_STALE;
  813                                 nd6_llinfo_settimer_locked(ln, (long)V_nd6_gctimer * hz);
  814                         }
  815                         goto freeit;
  816                 } else if (is_override                             /* (2a) */
  817                         || (!is_override && (lladdr != NULL && !llchange)) /* (2b) */
  818                         || lladdr == NULL) {                       /* (2c) */
  819                         /*
  820                          * Update link-local address, if any.
  821                          */
  822                         if (lladdr != NULL) {
  823                                 bcopy(lladdr, &ln->ll_addr, ifp->if_addrlen);
  824                                 ln->la_flags |= LLE_VALID;
  825                                 EVENTHANDLER_INVOKE(lle_event, ln,
  826                                     LLENTRY_RESOLVED);
  827                         }
  828 
  829                         /*
  830                          * If solicited, make the state REACHABLE.
  831                          * If not solicited and the link-layer address was
  832                          * changed, make it STALE.
  833                          */
  834                         if (is_solicited) {
  835                                 ln->ln_state = ND6_LLINFO_REACHABLE;
  836                                 ln->ln_byhint = 0;
  837                                 if (!ND6_LLINFO_PERMANENT(ln)) {
  838                                         nd6_llinfo_settimer_locked(ln,
  839                                             (long)ND_IFINFO(ifp)->reachable * hz);
  840                                 }
  841                         } else {
  842                                 if (lladdr != NULL && llchange) {
  843                                         ln->ln_state = ND6_LLINFO_STALE;
  844                                         nd6_llinfo_settimer_locked(ln,
  845                                             (long)V_nd6_gctimer * hz);
  846                                 }
  847                         }
  848                 }
  849 
  850                 if (ln->ln_router && !is_router) {
  851                         /*
  852                          * The peer dropped the router flag.
  853                          * Remove the sender from the Default Router List and
  854                          * update the Destination Cache entries.
  855                          */
  856                         struct nd_defrouter *dr;
  857                         struct in6_addr *in6;
  858 
  859                         in6 = &L3_ADDR_SIN6(ln)->sin6_addr;
  860 
  861                         /*
  862                          * Lock to protect the default router list.
  863                          * XXX: this might be unnecessary, since this function
  864                          * is only called under the network software interrupt
  865                          * context.  However, we keep it just for safety.
  866                          */
  867                         dr = defrouter_lookup(in6, ln->lle_tbl->llt_ifp);
  868                         if (dr)
  869                                 defrtrlist_del(dr);
  870                         else if (ND_IFINFO(ln->lle_tbl->llt_ifp)->flags &
  871                             ND6_IFF_ACCEPT_RTADV) {
  872                                 /*
  873                                  * Even if the neighbor is not in the default
  874                                  * router list, the neighbor may be used
  875                                  * as a next hop for some destinations
  876                                  * (e.g. redirect case). So we must
  877                                  * call rt6_flush explicitly.
  878                                  */
  879                                 rt6_flush(&ip6->ip6_src, ifp);
  880                         }
  881                 }
  882                 ln->ln_router = is_router;
  883         }
  884         /* XXX - QL
  885          *  Does this matter?
  886          *  rt->rt_flags &= ~RTF_REJECT;
  887          */
  888         ln->la_asked = 0;
  889         if (ln->la_hold) {
  890                 struct mbuf *m_hold, *m_hold_next;
  891 
  892                 /*
  893                  * reset the la_hold in advance, to explicitly
  894                  * prevent a la_hold lookup in nd6_output()
  895                  * (wouldn't happen, though...)
  896                  */
  897                 for (m_hold = ln->la_hold, ln->la_hold = NULL;
  898                     m_hold; m_hold = m_hold_next) {
  899                         m_hold_next = m_hold->m_nextpkt;
  900                         m_hold->m_nextpkt = NULL;
  901                         /*
  902                          * we assume ifp is not a loopback here, so just set
  903                          * the 2nd argument as the 1st one.
  904                          */
  905 
  906                         if (send_sendso_input_hook != NULL) {
  907                                 mtag = m_tag_get(PACKET_TAG_ND_OUTGOING,
  908                                     sizeof(unsigned short), M_NOWAIT);
  909                                 if (mtag == NULL)
  910                                         goto bad;
  911                                 m_tag_prepend(m, mtag);
  912                         }
  913 
  914                         nd6_output_lle(ifp, ifp, m_hold, L3_ADDR_SIN6(ln), NULL, ln, &chain);
  915                 }
  916         }
  917  freeit:
  918         if (ln != NULL) {
  919                 if (chain)
  920                         memcpy(&sin6, L3_ADDR_SIN6(ln), sizeof(sin6));
  921                 LLE_WUNLOCK(ln);
  922 
  923                 if (chain)
  924                         nd6_output_flush(ifp, ifp, chain, &sin6, NULL);
  925         }
  926         if (checklink)
  927                 pfxlist_onlink_check();
  928 
  929         m_freem(m);
  930         return;
  931 
  932  bad:
  933         if (ln != NULL)
  934                 LLE_WUNLOCK(ln);
  935 
  936         ICMP6STAT_INC(icp6s_badna);
  937         m_freem(m);
  938 }
  939 
  940 /*
  941  * Neighbor advertisement output handling.
  942  *
  943  * Based on RFC 2461
  944  *
  945  * the following items are not implemented yet:
  946  * - proxy advertisement delay rule (RFC2461 7.2.8, last paragraph, SHOULD)
  947  * - anycast advertisement delay rule (RFC2461 7.2.7, SHOULD)
  948  *
  949  * tlladdr - 1 if include target link-layer address
  950  * sdl0 - sockaddr_dl (= proxy NA) or NULL
  951  */
  952 static void
  953 nd6_na_output_fib(struct ifnet *ifp, const struct in6_addr *daddr6_0,
  954     const struct in6_addr *taddr6, u_long flags, int tlladdr,
  955     struct sockaddr *sdl0, u_int fibnum)
  956 {
  957         struct mbuf *m;
  958         struct m_tag *mtag;
  959         struct ifnet *oifp;
  960         struct ip6_hdr *ip6;
  961         struct nd_neighbor_advert *nd_na;
  962         struct ip6_moptions im6o;
  963         struct in6_addr src, daddr6;
  964         struct sockaddr_in6 dst_sa;
  965         int icmp6len, maxlen, error;
  966         caddr_t mac = NULL;
  967         struct route_in6 ro;
  968 
  969         bzero(&ro, sizeof(ro));
  970 
  971         daddr6 = *daddr6_0;     /* make a local copy for modification */
  972 
  973         /* estimate the size of message */
  974         maxlen = sizeof(*ip6) + sizeof(*nd_na);
  975         maxlen += (sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7;
  976         if (max_linkhdr + maxlen >= MCLBYTES) {
  977 #ifdef DIAGNOSTIC
  978                 printf("nd6_na_output: max_linkhdr + maxlen >= MCLBYTES "
  979                     "(%d + %d > %d)\n", max_linkhdr, maxlen, MCLBYTES);
  980 #endif
  981                 return;
  982         }
  983 
  984         if (max_linkhdr + maxlen > MHLEN)
  985                 m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
  986         else
  987                 m = m_gethdr(M_NOWAIT, MT_DATA);
  988         if (m == NULL)
  989                 return;
  990         M_SETFIB(m, fibnum);
  991 
  992         if (IN6_IS_ADDR_MULTICAST(&daddr6)) {
  993                 m->m_flags |= M_MCAST;
  994                 im6o.im6o_multicast_ifp = ifp;
  995                 im6o.im6o_multicast_hlim = 255;
  996                 im6o.im6o_multicast_loop = 0;
  997         }
  998 
  999         icmp6len = sizeof(*nd_na);
 1000         m->m_pkthdr.len = m->m_len = sizeof(struct ip6_hdr) + icmp6len;
 1001         m->m_data += max_linkhdr;       /* or MH_ALIGN() equivalent? */
 1002 
 1003         /* fill neighbor advertisement packet */
 1004         ip6 = mtod(m, struct ip6_hdr *);
 1005         ip6->ip6_flow = 0;
 1006         ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
 1007         ip6->ip6_vfc |= IPV6_VERSION;
 1008         ip6->ip6_nxt = IPPROTO_ICMPV6;
 1009         ip6->ip6_hlim = 255;
 1010         if (IN6_IS_ADDR_UNSPECIFIED(&daddr6)) {
 1011                 /* reply to DAD */
 1012                 daddr6.s6_addr16[0] = IPV6_ADDR_INT16_MLL;
 1013                 daddr6.s6_addr16[1] = 0;
 1014                 daddr6.s6_addr32[1] = 0;
 1015                 daddr6.s6_addr32[2] = 0;
 1016                 daddr6.s6_addr32[3] = IPV6_ADDR_INT32_ONE;
 1017                 if (in6_setscope(&daddr6, ifp, NULL))
 1018                         goto bad;
 1019 
 1020                 flags &= ~ND_NA_FLAG_SOLICITED;
 1021         }
 1022         ip6->ip6_dst = daddr6;
 1023         bzero(&dst_sa, sizeof(struct sockaddr_in6));
 1024         dst_sa.sin6_family = AF_INET6;
 1025         dst_sa.sin6_len = sizeof(struct sockaddr_in6);
 1026         dst_sa.sin6_addr = daddr6;
 1027 
 1028         /*
 1029          * Select a source whose scope is the same as that of the dest.
 1030          */
 1031         bcopy(&dst_sa, &ro.ro_dst, sizeof(dst_sa));
 1032         oifp = ifp;
 1033         error = in6_selectsrc(&dst_sa, NULL, NULL, &ro, NULL, &oifp, &src);
 1034         if (error) {
 1035                 char ip6buf[INET6_ADDRSTRLEN];
 1036                 nd6log((LOG_DEBUG, "nd6_na_output: source can't be "
 1037                     "determined: dst=%s, error=%d\n",
 1038                     ip6_sprintf(ip6buf, &dst_sa.sin6_addr), error));
 1039                 goto bad;
 1040         }
 1041         ip6->ip6_src = src;
 1042         nd_na = (struct nd_neighbor_advert *)(ip6 + 1);
 1043         nd_na->nd_na_type = ND_NEIGHBOR_ADVERT;
 1044         nd_na->nd_na_code = 0;
 1045         nd_na->nd_na_target = *taddr6;
 1046         in6_clearscope(&nd_na->nd_na_target); /* XXX */
 1047 
 1048         /*
 1049          * "tlladdr" indicates NS's condition for adding tlladdr or not.
 1050          * see nd6_ns_input() for details.
 1051          * Basically, if NS packet is sent to unicast/anycast addr,
 1052          * target lladdr option SHOULD NOT be included.
 1053          */
 1054         if (tlladdr) {
 1055                 /*
 1056                  * sdl0 != NULL indicates proxy NA.  If we do proxy, use
 1057                  * lladdr in sdl0.  If we are not proxying (sending NA for
 1058                  * my address) use lladdr configured for the interface.
 1059                  */
 1060                 if (sdl0 == NULL) {
 1061                         if (ifp->if_carp)
 1062                                 mac = (*carp_macmatch6_p)(ifp, m, taddr6);
 1063                         if (mac == NULL)
 1064                                 mac = nd6_ifptomac(ifp);
 1065                 } else if (sdl0->sa_family == AF_LINK) {
 1066                         struct sockaddr_dl *sdl;
 1067                         sdl = (struct sockaddr_dl *)sdl0;
 1068                         if (sdl->sdl_alen == ifp->if_addrlen)
 1069                                 mac = LLADDR(sdl);
 1070                 }
 1071         }
 1072         if (tlladdr && mac) {
 1073                 int optlen = sizeof(struct nd_opt_hdr) + ifp->if_addrlen;
 1074                 struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)(nd_na + 1);
 1075 
 1076                 /* roundup to 8 bytes alignment! */
 1077                 optlen = (optlen + 7) & ~7;
 1078 
 1079                 m->m_pkthdr.len += optlen;
 1080                 m->m_len += optlen;
 1081                 icmp6len += optlen;
 1082                 bzero((caddr_t)nd_opt, optlen);
 1083                 nd_opt->nd_opt_type = ND_OPT_TARGET_LINKADDR;
 1084                 nd_opt->nd_opt_len = optlen >> 3;
 1085                 bcopy(mac, (caddr_t)(nd_opt + 1), ifp->if_addrlen);
 1086         } else
 1087                 flags &= ~ND_NA_FLAG_OVERRIDE;
 1088 
 1089         ip6->ip6_plen = htons((u_short)icmp6len);
 1090         nd_na->nd_na_flags_reserved = flags;
 1091         nd_na->nd_na_cksum = 0;
 1092         nd_na->nd_na_cksum =
 1093             in6_cksum(m, IPPROTO_ICMPV6, sizeof(struct ip6_hdr), icmp6len);
 1094 
 1095         if (send_sendso_input_hook != NULL) {
 1096                 mtag = m_tag_get(PACKET_TAG_ND_OUTGOING,
 1097                     sizeof(unsigned short), M_NOWAIT);
 1098                 if (mtag == NULL)
 1099                         goto bad;
 1100                 *(unsigned short *)(mtag + 1) = nd_na->nd_na_type;
 1101                 m_tag_prepend(m, mtag);
 1102         }
 1103 
 1104         ip6_output(m, NULL, &ro, 0, &im6o, NULL, NULL);
 1105         icmp6_ifstat_inc(ifp, ifs6_out_msg);
 1106         icmp6_ifstat_inc(ifp, ifs6_out_neighboradvert);
 1107         ICMP6STAT_INC(icp6s_outhist[ND_NEIGHBOR_ADVERT]);
 1108 
 1109         /* We don't cache this route. */
 1110         RO_RTFREE(&ro);
 1111 
 1112         return;
 1113 
 1114   bad:
 1115         if (ro.ro_rt) {
 1116                 RTFREE(ro.ro_rt);
 1117         }
 1118         m_freem(m);
 1119         return;
 1120 }
 1121 
 1122 #ifndef BURN_BRIDGES
 1123 void
 1124 nd6_na_output(struct ifnet *ifp, const struct in6_addr *daddr6_0,
 1125     const struct in6_addr *taddr6, u_long flags, int tlladdr,
 1126     struct sockaddr *sdl0)
 1127 {
 1128 
 1129         nd6_na_output_fib(ifp, daddr6_0, taddr6, flags, tlladdr, sdl0,
 1130             RT_DEFAULT_FIB);
 1131 }
 1132 #endif
 1133 
 1134 caddr_t
 1135 nd6_ifptomac(struct ifnet *ifp)
 1136 {
 1137         switch (ifp->if_type) {
 1138         case IFT_ARCNET:
 1139         case IFT_ETHER:
 1140         case IFT_FDDI:
 1141         case IFT_IEEE1394:
 1142 #ifdef IFT_L2VLAN
 1143         case IFT_L2VLAN:
 1144 #endif
 1145 #ifdef IFT_IEEE80211
 1146         case IFT_IEEE80211:
 1147 #endif
 1148         case IFT_INFINIBAND:
 1149         case IFT_BRIDGE:
 1150         case IFT_ISO88025:
 1151                 return IF_LLADDR(ifp);
 1152         default:
 1153                 return NULL;
 1154         }
 1155 }
 1156 
 1157 struct dadq {
 1158         TAILQ_ENTRY(dadq) dad_list;
 1159         struct ifaddr *dad_ifa;
 1160         int dad_count;          /* max NS to send */
 1161         int dad_ns_tcount;      /* # of trials to send NS */
 1162         int dad_ns_ocount;      /* NS sent so far */
 1163         int dad_ns_icount;
 1164         int dad_na_icount;
 1165         struct callout dad_timer_ch;
 1166         struct vnet *dad_vnet;
 1167 };
 1168 
 1169 static VNET_DEFINE(TAILQ_HEAD(, dadq), dadq);
 1170 static VNET_DEFINE(struct rwlock, dad_rwlock);
 1171 #define V_dadq                  VNET(dadq)
 1172 #define V_dad_rwlock            VNET(dad_rwlock)
 1173 
 1174 #define DADQ_LOCK_INIT()        rw_init(&V_dad_rwlock, "nd6 DAD queue") 
 1175 #define DADQ_LOCK_DESTROY()     rw_destroy(&V_dad_rwlock)       
 1176 #define DADQ_LOCK_INITIALIZED() rw_initialized(&V_dad_rwlock)   
 1177 #define DADQ_RLOCK()            rw_rlock(&V_dad_rwlock) 
 1178 #define DADQ_RUNLOCK()          rw_runlock(&V_dad_rwlock)       
 1179 #define DADQ_WLOCK()            rw_wlock(&V_dad_rwlock) 
 1180 #define DADQ_WUNLOCK()          rw_wunlock(&V_dad_rwlock)       
 1181 
 1182 static struct dadq *
 1183 nd6_dad_find(struct ifaddr *ifa)
 1184 {
 1185         struct dadq *dp;
 1186 
 1187         DADQ_RLOCK();
 1188         TAILQ_FOREACH(dp, &V_dadq, dad_list)
 1189                 if (dp->dad_ifa == ifa)
 1190                         break;
 1191         DADQ_RUNLOCK();
 1192 
 1193         return (dp);
 1194 }
 1195 
 1196 static void
 1197 nd6_dad_starttimer(struct dadq *dp, int ticks)
 1198 {
 1199 
 1200         callout_reset(&dp->dad_timer_ch, ticks,
 1201             (void (*)(void *))nd6_dad_timer, (void *)dp);
 1202 }
 1203 
 1204 static void
 1205 nd6_dad_stoptimer(struct dadq *dp)
 1206 {
 1207 
 1208         callout_stop(&dp->dad_timer_ch);
 1209 }
 1210 
 1211 /*
 1212  * Start Duplicate Address Detection (DAD) for specified interface address.
 1213  */
 1214 void
 1215 nd6_dad_start(struct ifaddr *ifa, int delay)
 1216 {
 1217         struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
 1218         struct dadq *dp;
 1219         char ip6buf[INET6_ADDRSTRLEN];
 1220 
 1221         if (DADQ_LOCK_INITIALIZED() == 0) {
 1222                 DADQ_LOCK_INIT();
 1223                 TAILQ_INIT(&V_dadq);
 1224         }
 1225 
 1226         /*
 1227          * If we don't need DAD, don't do it.
 1228          * There are several cases:
 1229          * - DAD is disabled (ip6_dad_count == 0)
 1230          * - the interface address is anycast
 1231          */
 1232         if (!(ia->ia6_flags & IN6_IFF_TENTATIVE)) {
 1233                 log(LOG_DEBUG,
 1234                         "nd6_dad_start: called with non-tentative address "
 1235                         "%s(%s)\n",
 1236                         ip6_sprintf(ip6buf, &ia->ia_addr.sin6_addr),
 1237                         ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
 1238                 return;
 1239         }
 1240         if (ia->ia6_flags & IN6_IFF_ANYCAST) {
 1241                 ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
 1242                 return;
 1243         }
 1244         if (!V_ip6_dad_count) {
 1245                 ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
 1246                 return;
 1247         }
 1248         if (ifa->ifa_ifp == NULL)
 1249                 panic("nd6_dad_start: ifa->ifa_ifp == NULL");
 1250         if (!(ifa->ifa_ifp->if_flags & IFF_UP)) {
 1251                 return;
 1252         }
 1253         if (ND_IFINFO(ifa->ifa_ifp)->flags & ND6_IFF_IFDISABLED)
 1254                 return;
 1255         if (nd6_dad_find(ifa) != NULL) {
 1256                 /* DAD already in progress */
 1257                 return;
 1258         }
 1259 
 1260         dp = malloc(sizeof(*dp), M_IP6NDP, M_NOWAIT);
 1261         if (dp == NULL) {
 1262                 log(LOG_ERR, "nd6_dad_start: memory allocation failed for "
 1263                         "%s(%s)\n",
 1264                         ip6_sprintf(ip6buf, &ia->ia_addr.sin6_addr),
 1265                         ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
 1266                 return;
 1267         }
 1268         bzero(dp, sizeof(*dp));
 1269         callout_init(&dp->dad_timer_ch, 0);
 1270 #ifdef VIMAGE
 1271         dp->dad_vnet = curvnet;
 1272 #endif
 1273         DADQ_WLOCK();
 1274         TAILQ_INSERT_TAIL(&V_dadq, (struct dadq *)dp, dad_list);
 1275         DADQ_WUNLOCK();
 1276 
 1277         nd6log((LOG_DEBUG, "%s: starting DAD for %s\n", if_name(ifa->ifa_ifp),
 1278             ip6_sprintf(ip6buf, &ia->ia_addr.sin6_addr)));
 1279 
 1280         /*
 1281          * Send NS packet for DAD, ip6_dad_count times.
 1282          * Note that we must delay the first transmission, if this is the
 1283          * first packet to be sent from the interface after interface
 1284          * (re)initialization.
 1285          */
 1286         dp->dad_ifa = ifa;
 1287         ifa_ref(ifa);   /* just for safety */
 1288         dp->dad_count = V_ip6_dad_count;
 1289         dp->dad_ns_icount = dp->dad_na_icount = 0;
 1290         dp->dad_ns_ocount = dp->dad_ns_tcount = 0;
 1291         if (delay == 0) {
 1292                 nd6_dad_ns_output(dp, ifa);
 1293                 nd6_dad_starttimer(dp,
 1294                     (long)ND_IFINFO(ifa->ifa_ifp)->retrans * hz / 1000);
 1295         } else {
 1296                 nd6_dad_starttimer(dp, delay);
 1297         }
 1298 }
 1299 
 1300 /*
 1301  * terminate DAD unconditionally.  used for address removals.
 1302  */
 1303 void
 1304 nd6_dad_stop(struct ifaddr *ifa)
 1305 {
 1306         struct dadq *dp;
 1307 
 1308         if (DADQ_LOCK_INITIALIZED() == 0)
 1309                 return;
 1310         dp = nd6_dad_find(ifa);
 1311         if (!dp) {
 1312                 /* DAD wasn't started yet */
 1313                 return;
 1314         }
 1315 
 1316         nd6_dad_stoptimer(dp);
 1317 
 1318         DADQ_WLOCK();
 1319         TAILQ_REMOVE(&V_dadq, (struct dadq *)dp, dad_list);
 1320         DADQ_WUNLOCK();
 1321         free(dp, M_IP6NDP);
 1322         dp = NULL;
 1323         ifa_free(ifa);
 1324 }
 1325 
 1326 static void
 1327 nd6_dad_timer(struct dadq *dp)
 1328 {
 1329         CURVNET_SET(dp->dad_vnet);
 1330         struct ifaddr *ifa = dp->dad_ifa;
 1331         struct ifnet *ifp = dp->dad_ifa->ifa_ifp;
 1332         struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
 1333         char ip6buf[INET6_ADDRSTRLEN];
 1334 
 1335         /* Sanity check */
 1336         if (ia == NULL) {
 1337                 log(LOG_ERR, "nd6_dad_timer: called with null parameter\n");
 1338                 goto done;
 1339         }
 1340         if (ND_IFINFO(ifp)->flags & ND6_IFF_IFDISABLED) {
 1341                 /* Do not need DAD for ifdisabled interface. */
 1342                 TAILQ_REMOVE(&V_dadq, (struct dadq *)dp, dad_list);
 1343                 log(LOG_ERR, "nd6_dad_timer: cancel DAD on %s because of "
 1344                     "ND6_IFF_IFDISABLED.\n", ifp->if_xname);
 1345                 free(dp, M_IP6NDP);
 1346                 dp = NULL;
 1347                 ifa_free(ifa);
 1348                 goto done;
 1349         }
 1350         if (ia->ia6_flags & IN6_IFF_DUPLICATED) {
 1351                 log(LOG_ERR, "nd6_dad_timer: called with duplicated address "
 1352                         "%s(%s)\n",
 1353                         ip6_sprintf(ip6buf, &ia->ia_addr.sin6_addr),
 1354                         ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
 1355                 goto done;
 1356         }
 1357         if ((ia->ia6_flags & IN6_IFF_TENTATIVE) == 0) {
 1358                 log(LOG_ERR, "nd6_dad_timer: called with non-tentative address "
 1359                         "%s(%s)\n",
 1360                         ip6_sprintf(ip6buf, &ia->ia_addr.sin6_addr),
 1361                         ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
 1362                 goto done;
 1363         }
 1364 
 1365         /* timeouted with IFF_{RUNNING,UP} check */
 1366         if (dp->dad_ns_tcount > V_dad_maxtry) {
 1367                 nd6log((LOG_INFO, "%s: could not run DAD, driver problem?\n",
 1368                     if_name(ifa->ifa_ifp)));
 1369 
 1370                 DADQ_WLOCK();
 1371                 TAILQ_REMOVE(&V_dadq, (struct dadq *)dp, dad_list);
 1372                 DADQ_WUNLOCK();
 1373                 free(dp, M_IP6NDP);
 1374                 dp = NULL;
 1375                 ifa_free(ifa);
 1376                 goto done;
 1377         }
 1378 
 1379         /* Need more checks? */
 1380         if (dp->dad_ns_ocount < dp->dad_count) {
 1381                 /*
 1382                  * We have more NS to go.  Send NS packet for DAD.
 1383                  */
 1384                 nd6_dad_ns_output(dp, ifa);
 1385                 nd6_dad_starttimer(dp,
 1386                     (long)ND_IFINFO(ifa->ifa_ifp)->retrans * hz / 1000);
 1387         } else {
 1388                 /*
 1389                  * We have transmitted sufficient number of DAD packets.
 1390                  * See what we've got.
 1391                  */
 1392                 int duplicate;
 1393 
 1394                 duplicate = 0;
 1395 
 1396                 if (dp->dad_na_icount) {
 1397                         /*
 1398                          * the check is in nd6_dad_na_input(),
 1399                          * but just in case
 1400                          */
 1401                         duplicate++;
 1402                 }
 1403 
 1404                 if (dp->dad_ns_icount) {
 1405                         /* We've seen NS, means DAD has failed. */
 1406                         duplicate++;
 1407                 }
 1408 
 1409                 if (duplicate) {
 1410                         /* (*dp) will be freed in nd6_dad_duplicated() */
 1411                         dp = NULL;
 1412                         nd6_dad_duplicated(ifa);
 1413                 } else {
 1414                         /*
 1415                          * We are done with DAD.  No NA came, no NS came.
 1416                          * No duplicate address found.  Check IFDISABLED flag
 1417                          * again in case that it is changed between the
 1418                          * beginning of this function and here.
 1419                          */
 1420                         if ((ND_IFINFO(ifp)->flags & ND6_IFF_IFDISABLED) == 0)
 1421                                 ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
 1422 
 1423                         nd6log((LOG_DEBUG,
 1424                             "%s: DAD complete for %s - no duplicates found\n",
 1425                             if_name(ifa->ifa_ifp),
 1426                             ip6_sprintf(ip6buf, &ia->ia_addr.sin6_addr)));
 1427 
 1428                         DADQ_WLOCK();
 1429                         TAILQ_REMOVE(&V_dadq, (struct dadq *)dp, dad_list);
 1430                         DADQ_WUNLOCK();
 1431                         free(dp, M_IP6NDP);
 1432                         dp = NULL;
 1433                         ifa_free(ifa);
 1434                 }
 1435         }
 1436 
 1437 done:
 1438         CURVNET_RESTORE();
 1439 }
 1440 
 1441 void
 1442 nd6_dad_duplicated(struct ifaddr *ifa)
 1443 {
 1444         struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
 1445         struct ifnet *ifp;
 1446         struct dadq *dp;
 1447         char ip6buf[INET6_ADDRSTRLEN];
 1448 
 1449         dp = nd6_dad_find(ifa);
 1450         if (dp == NULL) {
 1451                 log(LOG_ERR, "nd6_dad_duplicated: DAD structure not found\n");
 1452                 return;
 1453         }
 1454 
 1455         log(LOG_ERR, "%s: DAD detected duplicate IPv6 address %s: "
 1456             "NS in/out=%d/%d, NA in=%d\n",
 1457             if_name(ifa->ifa_ifp), ip6_sprintf(ip6buf, &ia->ia_addr.sin6_addr),
 1458             dp->dad_ns_icount, dp->dad_ns_ocount, dp->dad_na_icount);
 1459 
 1460         ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
 1461         ia->ia6_flags |= IN6_IFF_DUPLICATED;
 1462 
 1463         /* We are done with DAD, with duplicate address found. (failure) */
 1464         nd6_dad_stoptimer(dp);
 1465 
 1466         ifp = ifa->ifa_ifp;
 1467         log(LOG_ERR, "%s: DAD complete for %s - duplicate found\n",
 1468             if_name(ifp), ip6_sprintf(ip6buf, &ia->ia_addr.sin6_addr));
 1469         log(LOG_ERR, "%s: manual intervention required\n",
 1470             if_name(ifp));
 1471 
 1472         /*
 1473          * If the address is a link-local address formed from an interface
 1474          * identifier based on the hardware address which is supposed to be
 1475          * uniquely assigned (e.g., EUI-64 for an Ethernet interface), IP
 1476          * operation on the interface SHOULD be disabled.
 1477          * [RFC 4862, Section 5.4.5]
 1478          */
 1479         if (IN6_IS_ADDR_LINKLOCAL(&ia->ia_addr.sin6_addr)) {
 1480                 struct in6_addr in6;
 1481 
 1482                 /*
 1483                  * To avoid over-reaction, we only apply this logic when we are
 1484                  * very sure that hardware addresses are supposed to be unique.
 1485                  */
 1486                 switch (ifp->if_type) {
 1487                 case IFT_ETHER:
 1488                 case IFT_FDDI:
 1489                 case IFT_ATM:
 1490                 case IFT_IEEE1394:
 1491 #ifdef IFT_IEEE80211
 1492                 case IFT_IEEE80211:
 1493 #endif
 1494                 case IFT_INFINIBAND:
 1495                         in6 = ia->ia_addr.sin6_addr;
 1496                         if (in6_get_hw_ifid(ifp, &in6) == 0 &&
 1497                             IN6_ARE_ADDR_EQUAL(&ia->ia_addr.sin6_addr, &in6)) {
 1498                                 ND_IFINFO(ifp)->flags |= ND6_IFF_IFDISABLED;
 1499                                 log(LOG_ERR, "%s: possible hardware address "
 1500                                     "duplication detected, disable IPv6\n",
 1501                                     if_name(ifp));
 1502                         }
 1503                         break;
 1504                 }
 1505         }
 1506 
 1507         DADQ_WLOCK();
 1508         TAILQ_REMOVE(&V_dadq, (struct dadq *)dp, dad_list);
 1509         DADQ_WUNLOCK();
 1510         free(dp, M_IP6NDP);
 1511         dp = NULL;
 1512         ifa_free(ifa);
 1513 }
 1514 
 1515 static void
 1516 nd6_dad_ns_output(struct dadq *dp, struct ifaddr *ifa)
 1517 {
 1518         struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
 1519         struct ifnet *ifp = ifa->ifa_ifp;
 1520 
 1521         dp->dad_ns_tcount++;
 1522         if ((ifp->if_flags & IFF_UP) == 0) {
 1523                 return;
 1524         }
 1525         if ((ifp->if_drv_flags & IFF_DRV_RUNNING) == 0) {
 1526                 return;
 1527         }
 1528 
 1529         dp->dad_ns_ocount++;
 1530         nd6_ns_output(ifp, NULL, &ia->ia_addr.sin6_addr, NULL, 1);
 1531 }
 1532 
 1533 static void
 1534 nd6_dad_ns_input(struct ifaddr *ifa)
 1535 {
 1536         struct in6_ifaddr *ia;
 1537         struct ifnet *ifp;
 1538         const struct in6_addr *taddr6;
 1539         struct dadq *dp;
 1540         int duplicate;
 1541 
 1542         if (ifa == NULL)
 1543                 panic("ifa == NULL in nd6_dad_ns_input");
 1544 
 1545         ia = (struct in6_ifaddr *)ifa;
 1546         ifp = ifa->ifa_ifp;
 1547         taddr6 = &ia->ia_addr.sin6_addr;
 1548         duplicate = 0;
 1549         dp = nd6_dad_find(ifa);
 1550 
 1551         /* Quickhack - completely ignore DAD NS packets */
 1552         if (V_dad_ignore_ns) {
 1553                 char ip6buf[INET6_ADDRSTRLEN];
 1554                 nd6log((LOG_INFO,
 1555                     "nd6_dad_ns_input: ignoring DAD NS packet for "
 1556                     "address %s(%s)\n", ip6_sprintf(ip6buf, taddr6),
 1557                     if_name(ifa->ifa_ifp)));
 1558                 return;
 1559         }
 1560 
 1561         /*
 1562          * if I'm yet to start DAD, someone else started using this address
 1563          * first.  I have a duplicate and you win.
 1564          */
 1565         if (dp == NULL || dp->dad_ns_ocount == 0)
 1566                 duplicate++;
 1567 
 1568         /* XXX more checks for loopback situation - see nd6_dad_timer too */
 1569 
 1570         if (duplicate) {
 1571                 dp = NULL;      /* will be freed in nd6_dad_duplicated() */
 1572                 nd6_dad_duplicated(ifa);
 1573         } else {
 1574                 /*
 1575                  * not sure if I got a duplicate.
 1576                  * increment ns count and see what happens.
 1577                  */
 1578                 if (dp)
 1579                         dp->dad_ns_icount++;
 1580         }
 1581 }
 1582 
 1583 static void
 1584 nd6_dad_na_input(struct ifaddr *ifa)
 1585 {
 1586         struct dadq *dp;
 1587 
 1588         if (ifa == NULL)
 1589                 panic("ifa == NULL in nd6_dad_na_input");
 1590 
 1591         dp = nd6_dad_find(ifa);
 1592         if (dp)
 1593                 dp->dad_na_icount++;
 1594 
 1595         /* remove the address. */
 1596         nd6_dad_duplicated(ifa);
 1597 }

Cache object: db09d959eb1fd4559c3cc57142a64170


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