sys/netinet6/icmp6.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-3-Clause
   3  *
   4  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the project nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  *
  31  *      $KAME: icmp6.c,v 1.211 2001/04/04 05:56:20 itojun Exp $
  32  */
  33
  34 /*-
  35  * Copyright (c) 1982, 1986, 1988, 1993
  36  *      The Regents of the University of California.  All rights reserved.
  37  *
  38  * Redistribution and use in source and binary forms, with or without
  39  * modification, are permitted provided that the following conditions
  40  * are met:
  41  * 1. Redistributions of source code must retain the above copyright
  42  *    notice, this list of conditions and the following disclaimer.
  43  * 2. Redistributions in binary form must reproduce the above copyright
  44  *    notice, this list of conditions and the following disclaimer in the
  45  *    documentation and/or other materials provided with the distribution.
  46  * 3. Neither the name of the University nor the names of its contributors
  47  *    may be used to endorse or promote products derived from this software
  48  *    without specific prior written permission.
  49  *
  50  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  51  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  52  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  53  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  54  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  55  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  56  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  57  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  58  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  59  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  60  * SUCH DAMAGE.
  61  */
  62
  63 #include <sys/cdefs.h>
  64 #define MBUF_PRIVATE    /* XXXRW: Optimisation tries to avoid M_EXT mbufs */
  65
  66 #include "opt_inet.h"
  67 #include "opt_inet6.h"
  68
  69 #include <sys/param.h>
  70 #include <sys/domain.h>
  71 #include <sys/jail.h>
  72 #include <sys/kernel.h>
  73 #include <sys/lock.h>
  74 #include <sys/malloc.h>
  75 #include <sys/mbuf.h>
  76 #include <sys/proc.h>
  77 #include <sys/protosw.h>
  78 #include <sys/signalvar.h>
  79 #include <sys/socket.h>
  80 #include <sys/socketvar.h>
  81 #include <sys/sx.h>
  82 #include <sys/syslog.h>
  83 #include <sys/systm.h>
  84 #include <sys/time.h>
  85
  86 #include <net/if.h>
  87 #include <net/if_var.h>
  88 #include <net/if_dl.h>
  89 #include <net/if_llatbl.h>
  90 #include <net/if_private.h>
  91 #include <net/if_types.h>
  92 #include <net/route.h>
  93 #include <net/route/route_ctl.h>
  94 #include <net/route/nhop.h>
  95 #include <net/vnet.h>
  96
  97 #include <netinet/in.h>
  98 #include <netinet/in_pcb.h>
  99 #include <netinet/in_var.h>
 100 #include <netinet/ip6.h>
 101 #include <netinet/icmp6.h>
 102 #include <netinet/tcp_var.h>
 103
 104 #include <netinet6/in6_fib.h>
 105 #include <netinet6/in6_ifattach.h>
 106 #include <netinet6/in6_pcb.h>
 107 #include <netinet6/ip6_var.h>
 108 #include <netinet6/scope6_var.h>
 109 #include <netinet6/mld6_var.h>
 110 #include <netinet6/nd6.h>
 111 #include <netinet6/send.h>
 112
 113 extern ip6proto_ctlinput_t      *ip6_ctlprotox[];
 114
 115 VNET_PCPUSTAT_DEFINE(struct icmp6stat, icmp6stat);
 116 VNET_PCPUSTAT_SYSINIT(icmp6stat);
 117 SYSCTL_VNET_PCPUSTAT(_net_inet6_icmp6, ICMPV6CTL_STATS, stats,
 118     struct icmp6stat, icmp6stat,
 119     "ICMPv6 statistics (struct icmp6stat, netinet/icmp6.h)");
 120
 121 #ifdef VIMAGE
 122 VNET_PCPUSTAT_SYSUNINIT(icmp6stat);
 123 #endif /* VIMAGE */
 124
 125 VNET_DEFINE_STATIC(int, icmp6_rediraccept) = 1;
 126 #define V_icmp6_rediraccept     VNET(icmp6_rediraccept)
 127 SYSCTL_INT(_net_inet6_icmp6, ICMPV6CTL_REDIRACCEPT, rediraccept,
 128     CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(icmp6_rediraccept), 0,
 129     "Accept ICMPv6 redirect messages");
 130
 131 VNET_DEFINE_STATIC(int, icmp6_redirtimeout) = 10 * 60;  /* 10 minutes */
 132 #define V_icmp6_redirtimeout    VNET(icmp6_redirtimeout)
 133 SYSCTL_INT(_net_inet6_icmp6, ICMPV6CTL_REDIRTIMEOUT, redirtimeout,
 134     CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(icmp6_redirtimeout), 0,
 135     "Delay in seconds before expiring redirect route");
 136
 137 VNET_DEFINE_STATIC(int, icmp6_nodeinfo) = 0;
 138 #define V_icmp6_nodeinfo        VNET(icmp6_nodeinfo)
 139 SYSCTL_INT(_net_inet6_icmp6, ICMPV6CTL_NODEINFO, nodeinfo,
 140     CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(icmp6_nodeinfo), 0,
 141     "Mask of enabled RFC4620 node information query types");
 142
 143 VNET_DECLARE(struct inpcbinfo, ripcbinfo);
 144 #define V_ripcbinfo             VNET(ripcbinfo)
 145
 146 static void icmp6_errcount(int, int);
 147 static int icmp6_rip6_input(struct mbuf **, int);
 148 static void icmp6_reflect(struct mbuf *, size_t);
 149 static const char *icmp6_redirect_diag(struct in6_addr *,
 150         struct in6_addr *, struct in6_addr *);
 151 static struct mbuf *ni6_input(struct mbuf *, int, struct prison *);
 152 static struct mbuf *ni6_nametodns(const char *, int, int);
 153 static int ni6_dnsmatch(const char *, int, const char *, int);
 154 static int ni6_addrs(struct icmp6_nodeinfo *, struct mbuf *,
 155                           struct ifnet **, struct in6_addr *);
 156 static int ni6_store_addrs(struct icmp6_nodeinfo *, struct icmp6_nodeinfo *,
 157                                 struct ifnet *, int);
 158 static int icmp6_notify_error(struct mbuf **, int, int);
 159
 160 /*
 161  * Kernel module interface for updating icmp6stat.  The argument is an index
 162  * into icmp6stat treated as an array of u_quad_t.  While this encodes the
 163  * general layout of icmp6stat into the caller, it doesn't encode its
 164  * location, so that future changes to add, for example, per-CPU stats
 165  * support won't cause binary compatibility problems for kernel modules.
 166  */
 167 void
 168 kmod_icmp6stat_inc(int statnum)
 169 {
 170
 171         counter_u64_add(VNET(icmp6stat)[statnum], 1);
 172 }
 173
 174 static void
 175 icmp6_errcount(int type, int code)
 176 {
 177         switch (type) {
 178         case ICMP6_DST_UNREACH:
 179                 switch (code) {
 180                 case ICMP6_DST_UNREACH_NOROUTE:
 181                         ICMP6STAT_INC(icp6s_odst_unreach_noroute);
 182                         return;
 183                 case ICMP6_DST_UNREACH_ADMIN:
 184                         ICMP6STAT_INC(icp6s_odst_unreach_admin);
 185                         return;
 186                 case ICMP6_DST_UNREACH_BEYONDSCOPE:
 187                         ICMP6STAT_INC(icp6s_odst_unreach_beyondscope);
 188                         return;
 189                 case ICMP6_DST_UNREACH_ADDR:
 190                         ICMP6STAT_INC(icp6s_odst_unreach_addr);
 191                         return;
 192                 case ICMP6_DST_UNREACH_NOPORT:
 193                         ICMP6STAT_INC(icp6s_odst_unreach_noport);
 194                         return;
 195                 }
 196                 break;
 197         case ICMP6_PACKET_TOO_BIG:
 198                 ICMP6STAT_INC(icp6s_opacket_too_big);
 199                 return;
 200         case ICMP6_TIME_EXCEEDED:
 201                 switch (code) {
 202                 case ICMP6_TIME_EXCEED_TRANSIT:
 203                         ICMP6STAT_INC(icp6s_otime_exceed_transit);
 204                         return;
 205                 case ICMP6_TIME_EXCEED_REASSEMBLY:
 206                         ICMP6STAT_INC(icp6s_otime_exceed_reassembly);
 207                         return;
 208                 }
 209                 break;
 210         case ICMP6_PARAM_PROB:
 211                 switch (code) {
 212                 case ICMP6_PARAMPROB_HEADER:
 213                         ICMP6STAT_INC(icp6s_oparamprob_header);
 214                         return;
 215                 case ICMP6_PARAMPROB_NEXTHEADER:
 216                         ICMP6STAT_INC(icp6s_oparamprob_nextheader);
 217                         return;
 218                 case ICMP6_PARAMPROB_OPTION:
 219                         ICMP6STAT_INC(icp6s_oparamprob_option);
 220                         return;
 221                 }
 222                 break;
 223         case ND_REDIRECT:
 224                 ICMP6STAT_INC(icp6s_oredirect);
 225                 return;
 226         }
 227         ICMP6STAT_INC(icp6s_ounknown);
 228 }
 229
 230 /*
 231  * A wrapper function for icmp6_error() necessary when the erroneous packet
 232  * may not contain enough scope zone information.
 233  */
 234 void
 235 icmp6_error2(struct mbuf *m, int type, int code, int param,
 236     struct ifnet *ifp)
 237 {
 238         struct ip6_hdr *ip6;
 239
 240         if (ifp == NULL)
 241                 return;
 242
 243         if (m->m_len < sizeof(struct ip6_hdr)) {
 244                 m = m_pullup(m, sizeof(struct ip6_hdr));
 245                 if (m == NULL) {
 246                         IP6STAT_INC(ip6s_exthdrtoolong);
 247                         return;
 248                 }
 249         }
 250         ip6 = mtod(m, struct ip6_hdr *);
 251
 252         if (in6_setscope(&ip6->ip6_src, ifp, NULL) != 0)
 253                 return;
 254         if (in6_setscope(&ip6->ip6_dst, ifp, NULL) != 0)
 255                 return;
 256
 257         icmp6_error(m, type, code, param);
 258 }
 259
 260 /*
 261  * Generate an error packet of type error in response to bad IP6 packet.
 262  */
 263 void
 264 icmp6_error(struct mbuf *m, int type, int code, int param)
 265 {
 266         struct ip6_hdr *oip6, *nip6;
 267         struct icmp6_hdr *icmp6;
 268         struct epoch_tracker et;
 269         u_int preplen;
 270         int off;
 271         int nxt;
 272
 273         ICMP6STAT_INC(icp6s_error);
 274
 275         /* count per-type-code statistics */
 276         icmp6_errcount(type, code);
 277
 278 #ifdef M_DECRYPTED      /*not openbsd*/
 279         if (m->m_flags & M_DECRYPTED) {
 280                 ICMP6STAT_INC(icp6s_canterror);
 281                 goto freeit;
 282         }
 283 #endif
 284
 285         if (m->m_len < sizeof(struct ip6_hdr)) {
 286                 m = m_pullup(m, sizeof(struct ip6_hdr));
 287                 if (m == NULL) {
 288                         IP6STAT_INC(ip6s_exthdrtoolong);
 289                         return;
 290                 }
 291         }
 292         oip6 = mtod(m, struct ip6_hdr *);
 293
 294         /*
 295          * If the destination address of the erroneous packet is a multicast
 296          * address, or the packet was sent using link-layer multicast,
 297          * we should basically suppress sending an error (RFC 2463, Section
 298          * 2.4).
 299          * We have two exceptions (the item e.2 in that section):
 300          * - the Packet Too Big message can be sent for path MTU discovery.
 301          * - the Parameter Problem Message that can be allowed an icmp6 error
 302          *   in the option type field.  This check has been done in
 303          *   ip6_unknown_opt(), so we can just check the type and code.
 304          */
 305         if ((m->m_flags & (M_BCAST|M_MCAST) ||
 306              IN6_IS_ADDR_MULTICAST(&oip6->ip6_dst)) &&
 307             (type != ICMP6_PACKET_TOO_BIG &&
 308              (type != ICMP6_PARAM_PROB ||
 309               code != ICMP6_PARAMPROB_OPTION)))
 310                 goto freeit;
 311
 312         /*
 313          * RFC 2463, 2.4 (e.5): source address check.
 314          * XXX: the case of anycast source?
 315          */
 316         if (IN6_IS_ADDR_UNSPECIFIED(&oip6->ip6_src) ||
 317             IN6_IS_ADDR_MULTICAST(&oip6->ip6_src))
 318                 goto freeit;
 319
 320         /*
 321          * If we are about to send ICMPv6 against ICMPv6 error/redirect,
 322          * don't do it.
 323          */
 324         nxt = -1;
 325         off = ip6_lasthdr(m, 0, IPPROTO_IPV6, &nxt);
 326         if (off >= 0 && nxt == IPPROTO_ICMPV6) {
 327                 struct icmp6_hdr *icp;
 328
 329                 if (m->m_len < off + sizeof(struct icmp6_hdr)) {
 330                         m = m_pullup(m, off + sizeof(struct icmp6_hdr));
 331                         if (m == NULL) {
 332                                 IP6STAT_INC(ip6s_exthdrtoolong);
 333                                 return;
 334                         }
 335                 }
 336                 oip6 = mtod(m, struct ip6_hdr *);
 337                 icp = (struct icmp6_hdr *)(mtod(m, caddr_t) + off);
 338
 339                 if (icp->icmp6_type < ICMP6_ECHO_REQUEST ||
 340                     icp->icmp6_type == ND_REDIRECT) {
 341                         /*
 342                          * ICMPv6 error
 343                          * Special case: for redirect (which is
 344                          * informational) we must not send icmp6 error.
 345                          */
 346                         ICMP6STAT_INC(icp6s_canterror);
 347                         goto freeit;
 348                 } else {
 349                         /* ICMPv6 informational - send the error */
 350                 }
 351         } else {
 352                 /* non-ICMPv6 - send the error */
 353         }
 354
 355         /* Finally, do rate limitation check. */
 356         if (icmp6_ratelimit(&oip6->ip6_src, type, code))
 357                 goto freeit;
 358
 359         /*
 360          * OK, ICMP6 can be generated.
 361          */
 362
 363         if (m->m_pkthdr.len >= ICMPV6_PLD_MAXLEN)
 364                 m_adj(m, ICMPV6_PLD_MAXLEN - m->m_pkthdr.len);
 365
 366         preplen = sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr);
 367         M_PREPEND(m, preplen, M_NOWAIT);        /* FIB is also copied over. */
 368         if (m == NULL) {
 369                 nd6log((LOG_DEBUG, "ENOBUFS in icmp6_error %d\n", __LINE__));
 370                 return;
 371         }
 372
 373         nip6 = mtod(m, struct ip6_hdr *);
 374         nip6->ip6_src  = oip6->ip6_src;
 375         nip6->ip6_dst  = oip6->ip6_dst;
 376
 377         in6_clearscope(&oip6->ip6_src);
 378         in6_clearscope(&oip6->ip6_dst);
 379
 380         icmp6 = (struct icmp6_hdr *)(nip6 + 1);
 381         icmp6->icmp6_type = type;
 382         icmp6->icmp6_code = code;
 383         icmp6->icmp6_pptr = htonl((u_int32_t)param);
 384
 385         ICMP6STAT_INC(icp6s_outhist[type]);
 386         NET_EPOCH_ENTER(et);
 387         icmp6_reflect(m, sizeof(struct ip6_hdr)); /* header order: IPv6 - ICMPv6 */
 388         NET_EPOCH_EXIT(et);
 389
 390         return;
 391
 392   freeit:
 393         /*
 394          * If we can't tell whether or not we can generate ICMP6, free it.
 395          */
 396         m_freem(m);
 397 }
 398
 399 int
 400 icmp6_errmap(const struct icmp6_hdr *icmp6)
 401 {
 402
 403         switch (icmp6->icmp6_type) {
 404         case ICMP6_DST_UNREACH:
 405                 switch (icmp6->icmp6_code) {
 406                 case ICMP6_DST_UNREACH_NOROUTE:
 407                 case ICMP6_DST_UNREACH_ADDR:
 408                         return (EHOSTUNREACH);
 409                 case ICMP6_DST_UNREACH_NOPORT:
 410                 case ICMP6_DST_UNREACH_ADMIN:
 411                         return (ECONNREFUSED);
 412                 case ICMP6_DST_UNREACH_BEYONDSCOPE:
 413                         return (ENOPROTOOPT);
 414                 default:
 415                         return (0);     /* Shouldn't happen. */
 416                 }
 417         case ICMP6_PACKET_TOO_BIG:
 418                 return (EMSGSIZE);
 419         case ICMP6_TIME_EXCEEDED:
 420                 switch (icmp6->icmp6_code) {
 421                 case ICMP6_TIME_EXCEED_TRANSIT:
 422                         return (EHOSTUNREACH);
 423                 case ICMP6_TIME_EXCEED_REASSEMBLY:
 424                         return (0);
 425                 default:
 426                         return (0);     /* Shouldn't happen. */
 427                 }
 428         case ICMP6_PARAM_PROB:
 429                 switch (icmp6->icmp6_code) {
 430                 case ICMP6_PARAMPROB_NEXTHEADER:
 431                         return (ECONNREFUSED);
 432                 case ICMP6_PARAMPROB_HEADER:
 433                 case ICMP6_PARAMPROB_OPTION:
 434                         return (ENOPROTOOPT);
 435                 default:
 436                         return (0);     /* Shouldn't happen. */
 437                 }
 438         default:
 439                 return (0);
 440         }
 441 }
 442
 443 /*
 444  * Process a received ICMP6 message.
 445  */
 446 int
 447 icmp6_input(struct mbuf **mp, int *offp, int proto)
 448 {
 449         struct mbuf *m, *n;
 450         struct ifnet *ifp;
 451         struct ip6_hdr *ip6, *nip6;
 452         struct icmp6_hdr *icmp6, *nicmp6;
 453         char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
 454         int code, error, icmp6len, ip6len, noff, off, sum;
 455
 456         NET_EPOCH_ASSERT();
 457
 458         m = *mp;
 459         off = *offp;
 460
 461         if (m->m_len < off + sizeof(struct icmp6_hdr)) {
 462                 m = m_pullup(m, off + sizeof(struct icmp6_hdr));
 463                 if (m == NULL) {
 464                         IP6STAT_INC(ip6s_exthdrtoolong);
 465                         *mp = m;
 466                         return (IPPROTO_DONE);
 467                 }
 468         }
 469
 470         /*
 471          * Locate icmp6 structure in mbuf, and check
 472          * that not corrupted and of at least minimum length
 473          */
 474
 475         icmp6len = m->m_pkthdr.len - off;
 476         if (icmp6len < sizeof(struct icmp6_hdr)) {
 477                 ICMP6STAT_INC(icp6s_tooshort);
 478                 goto freeit;
 479         }
 480
 481         ip6 = mtod(m, struct ip6_hdr *);
 482         ifp = m->m_pkthdr.rcvif;
 483         /*
 484          * Check multicast group membership.
 485          * Note: SSM filters are not applied for ICMPv6 traffic.
 486          */
 487         if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
 488                 struct in6_multi        *inm;
 489
 490                 inm = in6m_lookup(ifp, &ip6->ip6_dst);
 491                 if (inm == NULL) {
 492                         IP6STAT_INC(ip6s_notmember);
 493                         in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
 494                         goto freeit;
 495                 }
 496         }
 497
 498         /* Calculate the checksum. */
 499         icmp6 = (struct icmp6_hdr *)((caddr_t)ip6 + off);
 500         code = icmp6->icmp6_code;
 501         if ((sum = in6_cksum(m, IPPROTO_ICMPV6, off, icmp6len)) != 0) {
 502                 nd6log((LOG_ERR,
 503                     "ICMP6 checksum error(%d|%x) %s\n",
 504                     icmp6->icmp6_type, sum,
 505                     ip6_sprintf(ip6bufs, &ip6->ip6_src)));
 506                 ICMP6STAT_INC(icp6s_checksum);
 507                 goto freeit;
 508         }
 509
 510         ICMP6STAT_INC(icp6s_inhist[icmp6->icmp6_type]);
 511         icmp6_ifstat_inc(ifp, ifs6_in_msg);
 512         if (icmp6->icmp6_type < ICMP6_INFOMSG_MASK)
 513                 icmp6_ifstat_inc(ifp, ifs6_in_error);
 514
 515         ip6len = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen);
 516         switch (icmp6->icmp6_type) {
 517         case ICMP6_DST_UNREACH:
 518                 icmp6_ifstat_inc(ifp, ifs6_in_dstunreach);
 519                 switch (code) {
 520                 case ICMP6_DST_UNREACH_ADMIN:
 521                         icmp6_ifstat_inc(ifp, ifs6_in_adminprohib);
 522                 case ICMP6_DST_UNREACH_NOROUTE:
 523                 case ICMP6_DST_UNREACH_ADDR:
 524                 case ICMP6_DST_UNREACH_BEYONDSCOPE:
 525                 case ICMP6_DST_UNREACH_NOPORT:
 526                         goto deliver;
 527                 default:
 528                         goto badcode;
 529                 }
 530         case ICMP6_PACKET_TOO_BIG:
 531                 icmp6_ifstat_inc(ifp, ifs6_in_pkttoobig);
 532                 /*
 533                  * Validation is made in icmp6_mtudisc_update.
 534                  * Updating the path MTU will be done after examining
 535                  * intermediate extension headers.
 536                  */
 537                 goto deliver;
 538         case ICMP6_TIME_EXCEEDED:
 539                 icmp6_ifstat_inc(ifp, ifs6_in_timeexceed);
 540                 switch (code) {
 541                 case ICMP6_TIME_EXCEED_TRANSIT:
 542                 case ICMP6_TIME_EXCEED_REASSEMBLY:
 543                         goto deliver;
 544                 default:
 545                         goto badcode;
 546                 }
 547         case ICMP6_PARAM_PROB:
 548                 icmp6_ifstat_inc(ifp, ifs6_in_paramprob);
 549                 switch (code) {
 550                 case ICMP6_PARAMPROB_NEXTHEADER:
 551                 case ICMP6_PARAMPROB_HEADER:
 552                 case ICMP6_PARAMPROB_OPTION:
 553                         goto deliver;
 554                 default:
 555                         goto badcode;
 556                 }
 557         case ICMP6_ECHO_REQUEST:
 558                 icmp6_ifstat_inc(ifp, ifs6_in_echo);
 559                 if (code != 0)
 560                         goto badcode;
 561                 if (icmp6_ratelimit(&ip6->ip6_src, ICMP6_ECHO_REPLY, 0))
 562                         break;
 563                 if ((n = m_copym(m, 0, M_COPYALL, M_NOWAIT)) == NULL) {
 564                         /* Give up remote */
 565                         break;
 566                 }
 567                 if (!M_WRITABLE(n)
 568                  || n->m_len < off + sizeof(struct icmp6_hdr)) {
 569                         struct mbuf *n0 = n;
 570                         int n0len;
 571
 572                         CTASSERT(sizeof(*nip6) + sizeof(*nicmp6) <= MHLEN);
 573                         n = m_gethdr(M_NOWAIT, n0->m_type);
 574                         if (n == NULL) {
 575                                 /* Give up remote */
 576                                 m_freem(n0);
 577                                 break;
 578                         }
 579
 580                         m_move_pkthdr(n, n0);   /* FIB copied. */
 581                         n0len = n0->m_pkthdr.len;       /* save for use below */
 582                         /*
 583                          * Copy IPv6 and ICMPv6 only.
 584                          */
 585                         nip6 = mtod(n, struct ip6_hdr *);
 586                         bcopy(ip6, nip6, sizeof(struct ip6_hdr));
 587                         nicmp6 = (struct icmp6_hdr *)(nip6 + 1);
 588                         bcopy(icmp6, nicmp6, sizeof(struct icmp6_hdr));
 589                         noff = sizeof(struct ip6_hdr);
 590                         /* new mbuf contains only ipv6+icmpv6 headers */
 591                         n->m_len = noff + sizeof(struct icmp6_hdr);
 592                         /*
 593                          * Adjust mbuf.  ip6_plen will be adjusted in
 594                          * ip6_output().
 595                          */
 596                         m_adj(n0, off + sizeof(struct icmp6_hdr));
 597                         /* recalculate complete packet size */
 598                         n->m_pkthdr.len = n0len + (noff - off);
 599                         n->m_next = n0;
 600                 } else {
 601                         if (n->m_len < off + sizeof(*nicmp6)) {
 602                                 n = m_pullup(n, off + sizeof(*nicmp6));
 603                                 if (n == NULL) {
 604                                         IP6STAT_INC(ip6s_exthdrtoolong);
 605                                         break;
 606                                 }
 607                         }
 608                         nicmp6 = (struct icmp6_hdr *)(mtod(n, caddr_t) + off);
 609                         noff = off;
 610                 }
 611                 if (n) {
 612                         nicmp6->icmp6_type = ICMP6_ECHO_REPLY;
 613                         nicmp6->icmp6_code = 0;
 614                         ICMP6STAT_INC(icp6s_reflect);
 615                         ICMP6STAT_INC(icp6s_outhist[ICMP6_ECHO_REPLY]);
 616                         icmp6_reflect(n, noff);
 617                 }
 618                 break;
 619
 620         case ICMP6_ECHO_REPLY:
 621                 icmp6_ifstat_inc(ifp, ifs6_in_echoreply);
 622                 if (code != 0)
 623                         goto badcode;
 624                 break;
 625
 626         case MLD_LISTENER_QUERY:
 627         case MLD_LISTENER_REPORT:
 628         case MLD_LISTENER_DONE:
 629         case MLDV2_LISTENER_REPORT:
 630                 /*
 631                  * Drop MLD traffic which is not link-local, has a hop limit
 632                  * of greater than 1 hop, or which does not have the
 633                  * IPv6 HBH Router Alert option.
 634                  * As IPv6 HBH options are stripped in ip6_input() we must
 635                  * check an mbuf header flag.
 636                  * XXX Should we also sanity check that these messages
 637                  * were directed to a link-local multicast prefix?
 638                  */
 639                 if ((ip6->ip6_hlim != 1) || (m->m_flags & M_RTALERT_MLD) == 0)
 640                         goto freeit;
 641                 if (mld_input(&m, off, icmp6len) != 0) {
 642                         *mp = NULL;
 643                         return (IPPROTO_DONE);
 644                 }
 645                 /* m stays. */
 646                 break;
 647
 648         case ICMP6_WRUREQUEST:  /* ICMP6_FQDN_QUERY */
 649             {
 650                 enum { WRU, FQDN } mode;
 651                 struct prison *pr;
 652
 653                 if (!V_icmp6_nodeinfo)
 654                         break;
 655
 656                 if (icmp6len == sizeof(struct icmp6_hdr) + 4)
 657                         mode = WRU;
 658                 else if (icmp6len >= sizeof(struct icmp6_nodeinfo))
 659                         mode = FQDN;
 660                 else
 661                         goto badlen;
 662
 663                 pr = NULL;
 664                 sx_slock(&allprison_lock);
 665                 TAILQ_FOREACH(pr, &allprison, pr_list)
 666                         if (pr->pr_vnet == ifp->if_vnet)
 667                                 break;
 668                 sx_sunlock(&allprison_lock);
 669                 if (pr == NULL)
 670                         pr = curthread->td_ucred->cr_prison;
 671                 if (mode == FQDN) {
 672                         if (m->m_len < off + sizeof(struct icmp6_nodeinfo)) {
 673                                 m = m_pullup(m, off +
 674                                     sizeof(struct icmp6_nodeinfo));
 675                                 if (m == NULL) {
 676                                         IP6STAT_INC(ip6s_exthdrtoolong);
 677                                         *mp = m;
 678                                         return (IPPROTO_DONE);
 679                                 }
 680                         }
 681                         n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
 682                         if (n)
 683                                 n = ni6_input(n, off, pr);
 684                         /* XXX meaningless if n == NULL */
 685                         noff = sizeof(struct ip6_hdr);
 686                 } else {
 687                         u_char *p;
 688                         int maxhlen, hlen;
 689
 690                         /*
 691                          * XXX: this combination of flags is pointless,
 692                          * but should we keep this for compatibility?
 693                          */
 694                         if ((V_icmp6_nodeinfo & (ICMP6_NODEINFO_FQDNOK |
 695                             ICMP6_NODEINFO_TMPADDROK)) !=
 696                             (ICMP6_NODEINFO_FQDNOK | ICMP6_NODEINFO_TMPADDROK))
 697                                 break;
 698
 699                         if (code != 0)
 700                                 goto badcode;
 701
 702                         CTASSERT(sizeof(*nip6) + sizeof(*nicmp6) + 4 <= MHLEN);
 703                         n = m_gethdr(M_NOWAIT, m->m_type);
 704                         if (n == NULL) {
 705                                 /* Give up remote */
 706                                 break;
 707                         }
 708                         if (!m_dup_pkthdr(n, m, M_NOWAIT)) {
 709                                 /*
 710                                  * Previous code did a blind M_COPY_PKTHDR
 711                                  * and said "just for rcvif".  If true, then
 712                                  * we could tolerate the dup failing (due to
 713                                  * the deep copy of the tag chain).  For now
 714                                  * be conservative and just fail.
 715                                  */
 716                                 m_free(n);
 717                                 n = NULL;
 718                                 break;
 719                         }
 720                         /*
 721                          * Copy IPv6 and ICMPv6 only.
 722                          */
 723                         nip6 = mtod(n, struct ip6_hdr *);
 724                         bcopy(ip6, nip6, sizeof(struct ip6_hdr));
 725                         nicmp6 = (struct icmp6_hdr *)(nip6 + 1);
 726                         bcopy(icmp6, nicmp6, sizeof(struct icmp6_hdr));
 727                         p = (u_char *)(nicmp6 + 1);
 728                         bzero(p, 4);
 729
 730                         maxhlen = M_TRAILINGSPACE(n) -
 731                             (sizeof(*nip6) + sizeof(*nicmp6) + 4);
 732                         mtx_lock(&pr->pr_mtx);
 733                         hlen = strlen(pr->pr_hostname);
 734                         if (maxhlen > hlen)
 735                                 maxhlen = hlen;
 736                         /* meaningless TTL */
 737                         bcopy(pr->pr_hostname, p + 4, maxhlen);
 738                         mtx_unlock(&pr->pr_mtx);
 739                         noff = sizeof(struct ip6_hdr);
 740                         n->m_pkthdr.len = n->m_len = sizeof(struct ip6_hdr) +
 741                                 sizeof(struct icmp6_hdr) + 4 + maxhlen;
 742                         nicmp6->icmp6_type = ICMP6_WRUREPLY;
 743                         nicmp6->icmp6_code = 0;
 744                 }
 745                 if (n) {
 746                         ICMP6STAT_INC(icp6s_reflect);
 747                         ICMP6STAT_INC(icp6s_outhist[ICMP6_WRUREPLY]);
 748                         icmp6_reflect(n, noff);
 749                 }
 750                 break;
 751             }
 752
 753         case ICMP6_WRUREPLY:
 754                 if (code != 0)
 755                         goto badcode;
 756                 break;
 757
 758         case ND_ROUTER_SOLICIT:
 759                 icmp6_ifstat_inc(ifp, ifs6_in_routersolicit);
 760                 if (code != 0)
 761                         goto badcode;
 762                 if (icmp6len < sizeof(struct nd_router_solicit))
 763                         goto badlen;
 764                 if (send_sendso_input_hook != NULL) {
 765                         if (m->m_len < off + icmp6len) {
 766                                 m = m_pullup(m, off + icmp6len);
 767                                 if (m == NULL) {
 768                                         IP6STAT_INC(ip6s_exthdrtoolong);
 769                                         *mp = NULL;
 770                                         return (IPPROTO_DONE);
 771                                 }
 772                         }
 773                         error = send_sendso_input_hook(m, ifp, SND_IN, ip6len);
 774                         if (error == 0) {
 775                                 m = NULL;
 776                                 goto freeit;
 777                         }
 778                 }
 779                 n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
 780                 nd6_rs_input(m, off, icmp6len);
 781                 m = n;
 782                 if (m == NULL)
 783                         goto freeit;
 784                 break;
 785
 786         case ND_ROUTER_ADVERT:
 787                 icmp6_ifstat_inc(ifp, ifs6_in_routeradvert);
 788                 if (code != 0)
 789                         goto badcode;
 790                 if (icmp6len < sizeof(struct nd_router_advert))
 791                         goto badlen;
 792                 if (send_sendso_input_hook != NULL) {
 793                         error = send_sendso_input_hook(m, ifp, SND_IN, ip6len);
 794                         if (error == 0) {
 795                                 m = NULL;
 796                                 goto freeit;
 797                         }
 798                 }
 799                 n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
 800                 nd6_ra_input(m, off, icmp6len);
 801                 m = n;
 802                 if (m == NULL)
 803                         goto freeit;
 804                 break;
 805
 806         case ND_NEIGHBOR_SOLICIT:
 807                 icmp6_ifstat_inc(ifp, ifs6_in_neighborsolicit);
 808                 if (code != 0)
 809                         goto badcode;
 810                 if (icmp6len < sizeof(struct nd_neighbor_solicit))
 811                         goto badlen;
 812                 if (send_sendso_input_hook != NULL) {
 813                         error = send_sendso_input_hook(m, ifp, SND_IN, ip6len);
 814                         if (error == 0) {
 815                                 m = NULL;
 816                                 goto freeit;
 817                         }
 818                 }
 819                 n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
 820                 nd6_ns_input(m, off, icmp6len);
 821                 m = n;
 822                 if (m == NULL)
 823                         goto freeit;
 824                 break;
 825
 826         case ND_NEIGHBOR_ADVERT:
 827                 icmp6_ifstat_inc(ifp, ifs6_in_neighboradvert);
 828                 if (code != 0)
 829                         goto badcode;
 830                 if (icmp6len < sizeof(struct nd_neighbor_advert))
 831                         goto badlen;
 832                 if (send_sendso_input_hook != NULL) {
 833                         error = send_sendso_input_hook(m, ifp, SND_IN, ip6len);
 834                         if (error == 0) {
 835                                 m = NULL;
 836                                 goto freeit;
 837                         }
 838                 }
 839                 n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
 840                 nd6_na_input(m, off, icmp6len);
 841                 m = n;
 842                 if (m == NULL)
 843                         goto freeit;
 844                 break;
 845
 846         case ND_REDIRECT:
 847                 icmp6_ifstat_inc(ifp, ifs6_in_redirect);
 848                 if (code != 0)
 849                         goto badcode;
 850                 if (icmp6len < sizeof(struct nd_redirect))
 851                         goto badlen;
 852                 if (send_sendso_input_hook != NULL) {
 853                         error = send_sendso_input_hook(m, ifp, SND_IN, ip6len);
 854                         if (error == 0) {
 855                                 m = NULL;
 856                                 goto freeit;
 857                         }
 858                 }
 859                 n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
 860                 icmp6_redirect_input(m, off);
 861                 m = n;
 862                 if (m == NULL)
 863                         goto freeit;
 864                 break;
 865
 866         case ICMP6_ROUTER_RENUMBERING:
 867                 if (code != ICMP6_ROUTER_RENUMBERING_COMMAND &&
 868                     code != ICMP6_ROUTER_RENUMBERING_RESULT)
 869                         goto badcode;
 870                 if (icmp6len < sizeof(struct icmp6_router_renum))
 871                         goto badlen;
 872                 break;
 873
 874         default:
 875                 nd6log((LOG_DEBUG,
 876                     "icmp6_input: unknown type %d(src=%s, dst=%s, ifid=%d)\n",
 877                     icmp6->icmp6_type, ip6_sprintf(ip6bufs, &ip6->ip6_src),
 878                     ip6_sprintf(ip6bufd, &ip6->ip6_dst),
 879                     ifp ? ifp->if_index : 0));
 880                 if (icmp6->icmp6_type < ICMP6_ECHO_REQUEST) {
 881                         /* ICMPv6 error: MUST deliver it by spec... */
 882                         goto deliver;
 883                 } else {
 884                         /* ICMPv6 informational: MUST not deliver */
 885                         break;
 886                 }
 887         deliver:
 888                 if (icmp6_notify_error(&m, off, icmp6len) != 0) {
 889                         /* In this case, m should've been freed. */
 890                         *mp = NULL;
 891                         return (IPPROTO_DONE);
 892                 }
 893                 break;
 894
 895         badcode:
 896                 ICMP6STAT_INC(icp6s_badcode);
 897                 break;
 898
 899         badlen:
 900                 ICMP6STAT_INC(icp6s_badlen);
 901                 break;
 902         }
 903
 904         /* deliver the packet to appropriate sockets */
 905         icmp6_rip6_input(&m, *offp);
 906
 907         *mp = m;
 908         return (IPPROTO_DONE);
 909
 910  freeit:
 911         m_freem(m);
 912         *mp = NULL;
 913         return (IPPROTO_DONE);
 914 }
 915
 916 static int
 917 icmp6_notify_error(struct mbuf **mp, int off, int icmp6len)
 918 {
 919         struct mbuf *m;
 920         struct icmp6_hdr *icmp6;
 921         struct ip6_hdr *eip6;
 922         u_int32_t notifymtu;
 923         struct sockaddr_in6 icmp6src, icmp6dst;
 924
 925         m = *mp;
 926
 927         if (icmp6len < sizeof(struct icmp6_hdr) + sizeof(struct ip6_hdr)) {
 928                 ICMP6STAT_INC(icp6s_tooshort);
 929                 goto freeit;
 930         }
 931
 932         if (m->m_len < off + sizeof(*icmp6) + sizeof(struct ip6_hdr)) {
 933                 m = m_pullup(m, off + sizeof(*icmp6) + sizeof(struct ip6_hdr));
 934                 if (m == NULL) {
 935                         IP6STAT_INC(ip6s_exthdrtoolong);
 936                         *mp = m;
 937                         return (-1);
 938                 }
 939         }
 940         icmp6 = (struct icmp6_hdr *)(mtod(m, caddr_t) + off);
 941         eip6 = (struct ip6_hdr *)(icmp6 + 1);
 942         bzero(&icmp6dst, sizeof(icmp6dst));
 943
 944         /* Detect the upper level protocol */
 945         {
 946                 u_int8_t nxt = eip6->ip6_nxt;
 947                 int eoff = off + sizeof(struct icmp6_hdr) +
 948                     sizeof(struct ip6_hdr);
 949                 struct ip6ctlparam ip6cp;
 950                 int icmp6type = icmp6->icmp6_type;
 951                 struct ip6_frag *fh;
 952                 struct ip6_rthdr *rth;
 953                 struct ip6_rthdr0 *rth0;
 954                 int rthlen;
 955
 956                 while (1) { /* XXX: should avoid infinite loop explicitly? */
 957                         struct ip6_ext *eh;
 958
 959                         switch (nxt) {
 960                         case IPPROTO_HOPOPTS:
 961                         case IPPROTO_DSTOPTS:
 962                         case IPPROTO_AH:
 963                                 if (m->m_len < eoff + sizeof(struct ip6_ext)) {
 964                                         m = m_pullup(m, eoff +
 965                                             sizeof(struct ip6_ext));
 966                                         if (m == NULL) {
 967                                                 IP6STAT_INC(ip6s_exthdrtoolong);
 968                                                 *mp = m;
 969                                                 return (-1);
 970                                         }
 971                                 }
 972                                 eh = (struct ip6_ext *)
 973                                     (mtod(m, caddr_t) + eoff);
 974                                 if (nxt == IPPROTO_AH)
 975                                         eoff += (eh->ip6e_len + 2) << 2;
 976                                 else
 977                                         eoff += (eh->ip6e_len + 1) << 3;
 978                                 nxt = eh->ip6e_nxt;
 979                                 break;
 980                         case IPPROTO_ROUTING:
 981                                 /*
 982                                  * When the erroneous packet contains a
 983                                  * routing header, we should examine the
 984                                  * header to determine the final destination.
 985                                  * Otherwise, we can't properly update
 986                                  * information that depends on the final
 987                                  * destination (e.g. path MTU).
 988                                  */
 989                                 if (m->m_len < eoff + sizeof(*rth)) {
 990                                         m = m_pullup(m, eoff + sizeof(*rth));
 991                                         if (m == NULL) {
 992                                                 IP6STAT_INC(ip6s_exthdrtoolong);
 993                                                 *mp = m;
 994                                                 return (-1);
 995                                         }
 996                                 }
 997                                 rth = (struct ip6_rthdr *)
 998                                     (mtod(m, caddr_t) + eoff);
 999                                 rthlen = (rth->ip6r_len + 1) << 3;
1000                                 /*
1001                                  * XXX: currently there is no
1002                                  * officially defined type other
1003                                  * than type-0.
1004                                  * Note that if the segment left field
1005                                  * is 0, all intermediate hops must
1006                                  * have been passed.
1007                                  */
1008                                 if (rth->ip6r_segleft &&
1009                                     rth->ip6r_type == IPV6_RTHDR_TYPE_0) {
1010                                         int hops;
1011
1012                                         if (m->m_len < eoff + rthlen) {
1013                                                 m = m_pullup(m, eoff + rthlen);
1014                                                 if (m == NULL) {
1015                                                         IP6STAT_INC(
1016                                                             ip6s_exthdrtoolong);
1017                                                         *mp = m;
1018                                                         return (-1);
1019                                                 }
1020                                         }
1021                                         rth0 = (struct ip6_rthdr0 *)
1022                                             (mtod(m, caddr_t) + eoff);
1023
1024                                         /* just ignore a bogus header */
1025                                         if ((rth0->ip6r0_len % 2) == 0 &&
1026                                             (hops = rth0->ip6r0_len/2))
1027                                                 icmp6dst.sin6_addr = *((struct in6_addr *)(rth0 + 1) + (hops - 1));
1028                                 }
1029                                 eoff += rthlen;
1030                                 nxt = rth->ip6r_nxt;
1031                                 break;
1032                         case IPPROTO_FRAGMENT:
1033                                 if (m->m_len < eoff + sizeof(struct ip6_frag)) {
1034                                         m = m_pullup(m, eoff +
1035                                             sizeof(struct ip6_frag));
1036                                         if (m == NULL) {
1037                                                 IP6STAT_INC(ip6s_exthdrtoolong);
1038                                                 *mp = m;
1039                                                 return (-1);
1040                                         }
1041                                 }
1042                                 fh = (struct ip6_frag *)(mtod(m, caddr_t) +
1043                                     eoff);
1044                                 /*
1045                                  * Data after a fragment header is meaningless
1046                                  * unless it is the first fragment, but
1047                                  * we'll go to the notify label for path MTU
1048                                  * discovery.
1049                                  */
1050                                 if (fh->ip6f_offlg & IP6F_OFF_MASK)
1051                                         goto notify;
1052
1053                                 eoff += sizeof(struct ip6_frag);
1054                                 nxt = fh->ip6f_nxt;
1055                                 break;
1056                         default:
1057                                 /*
1058                                  * This case includes ESP and the No Next
1059                                  * Header.  In such cases going to the notify
1060                                  * label does not have any meaning
1061                                  * (i.e. ctlfunc will be NULL), but we go
1062                                  * anyway since we might have to update
1063                                  * path MTU information.
1064                                  */
1065                                 goto notify;
1066                         }
1067                 }
1068           notify:
1069                 icmp6 = (struct icmp6_hdr *)(mtod(m, caddr_t) + off);
1070
1071                 /*
1072                  * retrieve parameters from the inner IPv6 header, and convert
1073                  * them into sockaddr structures.
1074                  * XXX: there is no guarantee that the source or destination
1075                  * addresses of the inner packet are in the same scope as
1076                  * the addresses of the icmp packet.  But there is no other
1077                  * way to determine the zone.
1078                  */
1079                 eip6 = (struct ip6_hdr *)(icmp6 + 1);
1080
1081                 /*
1082                  * Protocol layers can't do anything useful with unspecified
1083                  * addresses.
1084                  */
1085                 if (IN6_IS_ADDR_UNSPECIFIED(&eip6->ip6_src) ||
1086                     IN6_IS_ADDR_UNSPECIFIED(&eip6->ip6_dst))
1087                         goto freeit;
1088
1089                 icmp6dst.sin6_len = sizeof(struct sockaddr_in6);
1090                 icmp6dst.sin6_family = AF_INET6;
1091                 if (IN6_IS_ADDR_UNSPECIFIED(&icmp6dst.sin6_addr))
1092                         icmp6dst.sin6_addr = eip6->ip6_dst;
1093                 if (in6_setscope(&icmp6dst.sin6_addr, m->m_pkthdr.rcvif, NULL))
1094                         goto freeit;
1095                 bzero(&icmp6src, sizeof(icmp6src));
1096                 icmp6src.sin6_len = sizeof(struct sockaddr_in6);
1097                 icmp6src.sin6_family = AF_INET6;
1098                 icmp6src.sin6_addr = eip6->ip6_src;
1099                 if (in6_setscope(&icmp6src.sin6_addr, m->m_pkthdr.rcvif, NULL))
1100                         goto freeit;
1101                 icmp6src.sin6_flowinfo =
1102                     (eip6->ip6_flow & IPV6_FLOWLABEL_MASK);
1103
1104                 ip6cp.ip6c_m = m;
1105                 ip6cp.ip6c_icmp6 = icmp6;
1106                 ip6cp.ip6c_ip6 = (struct ip6_hdr *)(icmp6 + 1);
1107                 ip6cp.ip6c_off = eoff;
1108                 ip6cp.ip6c_finaldst = &icmp6dst;
1109                 ip6cp.ip6c_src = &icmp6src;
1110                 ip6cp.ip6c_nxt = nxt;
1111
1112                 if (icmp6type == ICMP6_PACKET_TOO_BIG) {
1113                         notifymtu = ntohl(icmp6->icmp6_mtu);
1114                         ip6cp.ip6c_cmdarg = (void *)&notifymtu;
1115                         icmp6_mtudisc_update(&ip6cp, 1);        /*XXX*/
1116                 }
1117
1118                 if (ip6_ctlprotox[nxt] != NULL)
1119                         ip6_ctlprotox[nxt](&ip6cp);
1120         }
1121         *mp = m;
1122         return (0);
1123
1124   freeit:
1125         m_freem(m);
1126         *mp = NULL;
1127         return (-1);
1128 }
1129
1130 void
1131 icmp6_mtudisc_update(struct ip6ctlparam *ip6cp, int validated)
1132 {
1133         struct in6_addr *dst = &ip6cp->ip6c_finaldst->sin6_addr;
1134         struct icmp6_hdr *icmp6 = ip6cp->ip6c_icmp6;
1135         struct mbuf *m = ip6cp->ip6c_m; /* will be necessary for scope issue */
1136         u_int mtu = ntohl(icmp6->icmp6_mtu);
1137         struct in_conninfo inc;
1138         uint32_t max_mtu;
1139
1140 #if 0
1141         /*
1142          * RFC2460 section 5, last paragraph.
1143          * even though minimum link MTU for IPv6 is IPV6_MMTU,
1144          * we may see ICMPv6 too big with mtu < IPV6_MMTU
1145          * due to packet translator in the middle.
1146          * see ip6_output() and ip6_getpmtu() "alwaysfrag" case for
1147          * special handling.
1148          */
1149         if (mtu < IPV6_MMTU)
1150                 return;
1151 #endif
1152
1153         /*
1154          * we reject ICMPv6 too big with abnormally small value.
1155          * XXX what is the good definition of "abnormally small"?
1156          */
1157         if (mtu < sizeof(struct ip6_hdr) + sizeof(struct ip6_frag) + 8)
1158                 return;
1159
1160         if (!validated)
1161                 return;
1162
1163         /*
1164          * In case the suggested mtu is less than IPV6_MMTU, we
1165          * only need to remember that it was for above mentioned
1166          * "alwaysfrag" case.
1167          * Try to be as close to the spec as possible.
1168          */
1169         if (mtu < IPV6_MMTU)
1170                 mtu = IPV6_MMTU - 8;
1171
1172         bzero(&inc, sizeof(inc));
1173         inc.inc_fibnum = M_GETFIB(m);
1174         inc.inc_flags |= INC_ISIPV6;
1175         inc.inc6_faddr = *dst;
1176         if (in6_setscope(&inc.inc6_faddr, m->m_pkthdr.rcvif, NULL))
1177                 return;
1178
1179         max_mtu = tcp_hc_getmtu(&inc);
1180         if (max_mtu == 0)
1181                 max_mtu = tcp_maxmtu6(&inc, NULL);
1182
1183         if (mtu < max_mtu) {
1184                 tcp_hc_updatemtu(&inc, mtu);
1185                 ICMP6STAT_INC(icp6s_pmtuchg);
1186         }
1187 }
1188
1189 /*
1190  * Process a Node Information Query packet, based on
1191  * draft-ietf-ipngwg-icmp-name-lookups-07.
1192  *
1193  * Spec incompatibilities:
1194  * - IPv6 Subject address handling
1195  * - IPv4 Subject address handling support missing
1196  * - Proxy reply (answer even if it's not for me)
1197  * - joins NI group address at in6_ifattach() time only, does not cope
1198  *   with hostname changes by sethostname(3)
1199  */
1200 static struct mbuf *
1201 ni6_input(struct mbuf *m, int off, struct prison *pr)
1202 {
1203         struct icmp6_nodeinfo *ni6, *nni6;
1204         struct mbuf *n = NULL;
1205         u_int16_t qtype;
1206         int subjlen;
1207         int replylen = sizeof(struct ip6_hdr) + sizeof(struct icmp6_nodeinfo);
1208         struct ni_reply_fqdn *fqdn;
1209         int addrs;              /* for NI_QTYPE_NODEADDR */
1210         struct ifnet *ifp = NULL; /* for NI_QTYPE_NODEADDR */
1211         struct in6_addr in6_subj; /* subject address */
1212         struct ip6_hdr *ip6;
1213         int oldfqdn = 0;        /* if 1, return pascal string (03 draft) */
1214         char *subj = NULL;
1215         struct in6_ifaddr *ia6 = NULL;
1216
1217         ip6 = mtod(m, struct ip6_hdr *);
1218         ni6 = (struct icmp6_nodeinfo *)(mtod(m, caddr_t) + off);
1219
1220         /*
1221          * Validate IPv6 source address.
1222          * The default configuration MUST be to refuse answering queries from
1223          * global-scope addresses according to RFC4602.
1224          * Notes:
1225          *  - it's not very clear what "refuse" means; this implementation
1226          *    simply drops it.
1227          *  - it's not very easy to identify global-scope (unicast) addresses
1228          *    since there are many prefixes for them.  It should be safer
1229          *    and in practice sufficient to check "all" but loopback and
1230          *    link-local (note that site-local unicast was deprecated and
1231          *    ULA is defined as global scope-wise)
1232          */
1233         if ((V_icmp6_nodeinfo & ICMP6_NODEINFO_GLOBALOK) == 0 &&
1234             !IN6_IS_ADDR_LOOPBACK(&ip6->ip6_src) &&
1235             !IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_src))
1236                 goto bad;
1237
1238         /*
1239          * Validate IPv6 destination address.
1240          *
1241          * The Responder must discard the Query without further processing
1242          * unless it is one of the Responder's unicast or anycast addresses, or
1243          * a link-local scope multicast address which the Responder has joined.
1244          * [RFC4602, Section 5.]
1245          */
1246         if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
1247                 if (!IN6_IS_ADDR_MC_LINKLOCAL(&ip6->ip6_dst))
1248                         goto bad;
1249                 /* else it's a link-local multicast, fine */
1250         } else {                /* unicast or anycast */
1251                 ia6 = in6ifa_ifwithaddr(&ip6->ip6_dst, 0 /* XXX */, false);
1252                 if (ia6 == NULL)
1253                         goto bad; /* XXX impossible */
1254
1255                 if ((ia6->ia6_flags & IN6_IFF_TEMPORARY) &&
1256                     !(V_icmp6_nodeinfo & ICMP6_NODEINFO_TMPADDROK)) {
1257                         nd6log((LOG_DEBUG, "ni6_input: ignore node info to "
1258                                 "a temporary address in %s:%d",
1259                                __FILE__, __LINE__));
1260                         goto bad;
1261                 }
1262         }
1263
1264         /* validate query Subject field. */
1265         qtype = ntohs(ni6->ni_qtype);
1266         subjlen = m->m_pkthdr.len - off - sizeof(struct icmp6_nodeinfo);
1267         switch (qtype) {
1268         case NI_QTYPE_NOOP:
1269         case NI_QTYPE_SUPTYPES:
1270                 /* 07 draft */
1271                 if (ni6->ni_code == ICMP6_NI_SUBJ_FQDN && subjlen == 0)
1272                         break;
1273                 /* FALLTHROUGH */
1274         case NI_QTYPE_FQDN:
1275         case NI_QTYPE_NODEADDR:
1276         case NI_QTYPE_IPV4ADDR:
1277                 switch (ni6->ni_code) {
1278                 case ICMP6_NI_SUBJ_IPV6:
1279 #if ICMP6_NI_SUBJ_IPV6 != 0
1280                 case 0:
1281 #endif
1282                         /*
1283                          * backward compatibility - try to accept 03 draft
1284                          * format, where no Subject is present.
1285                          */
1286                         if (qtype == NI_QTYPE_FQDN && ni6->ni_code == 0 &&
1287                             subjlen == 0) {
1288                                 oldfqdn++;
1289                                 break;
1290                         }
1291 #if ICMP6_NI_SUBJ_IPV6 != 0
1292                         if (ni6->ni_code != ICMP6_NI_SUBJ_IPV6)
1293                                 goto bad;
1294 #endif
1295
1296                         if (subjlen != sizeof(struct in6_addr))
1297                                 goto bad;
1298
1299                         /*
1300                          * Validate Subject address.
1301                          *
1302                          * Not sure what exactly "address belongs to the node"
1303                          * means in the spec, is it just unicast, or what?
1304                          *
1305                          * At this moment we consider Subject address as
1306                          * "belong to the node" if the Subject address equals
1307                          * to the IPv6 destination address; validation for
1308                          * IPv6 destination address should have done enough
1309                          * check for us.
1310                          *
1311                          * We do not do proxy at this moment.
1312                          */
1313                         m_copydata(m, off + sizeof(struct icmp6_nodeinfo),
1314                             subjlen, (caddr_t)&in6_subj);
1315                         if (in6_setscope(&in6_subj, m->m_pkthdr.rcvif, NULL))
1316                                 goto bad;
1317
1318                         subj = (char *)&in6_subj;
1319                         if (IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &in6_subj))
1320                                 break;
1321
1322                         /*
1323                          * XXX if we are to allow other cases, we should really
1324                          * be careful about scope here.
1325                          * basically, we should disallow queries toward IPv6
1326                          * destination X with subject Y,
1327                          * if scope(X) > scope(Y).
1328                          * if we allow scope(X) > scope(Y), it will result in
1329                          * information leakage across scope boundary.
1330                          */
1331                         goto bad;
1332
1333                 case ICMP6_NI_SUBJ_FQDN:
1334                         /*
1335                          * Validate Subject name with gethostname(3).
1336                          *
1337                          * The behavior may need some debate, since:
1338                          * - we are not sure if the node has FQDN as
1339                          *   hostname (returned by gethostname(3)).
1340                          * - the code does wildcard match for truncated names.
1341                          *   however, we are not sure if we want to perform
1342                          *   wildcard match, if gethostname(3) side has
1343                          *   truncated hostname.
1344                          */
1345                         mtx_lock(&pr->pr_mtx);
1346                         n = ni6_nametodns(pr->pr_hostname,
1347                             strlen(pr->pr_hostname), 0);
1348                         mtx_unlock(&pr->pr_mtx);
1349                         if (!n || n->m_next || n->m_len == 0)
1350                                 goto bad;
1351                         if (m->m_len < off + sizeof(struct icmp6_nodeinfo) +
1352                             subjlen) {
1353                                 m = m_pullup(m, off +
1354                                     sizeof(struct icmp6_nodeinfo) + subjlen);
1355                                 if (m == NULL) {
1356                                         IP6STAT_INC(ip6s_exthdrtoolong);
1357                                         goto bad;
1358                                 }
1359                         }
1360                         /* ip6 possibly invalid but not used after. */
1361                         ni6 = (struct icmp6_nodeinfo *)(mtod(m, caddr_t) + off);
1362                         subj = (char *)(mtod(m, caddr_t) + off +
1363                             sizeof(struct icmp6_nodeinfo));
1364                         if (!ni6_dnsmatch(subj, subjlen, mtod(n, const char *),
1365                             n->m_len)) {
1366                                 goto bad;
1367                         }
1368                         m_freem(n);
1369                         n = NULL;
1370                         break;
1371
1372                 case ICMP6_NI_SUBJ_IPV4:        /* XXX: to be implemented? */
1373                 default:
1374                         goto bad;
1375                 }
1376                 break;
1377         }
1378
1379         /* refuse based on configuration.  XXX ICMP6_NI_REFUSED? */
1380         switch (qtype) {
1381         case NI_QTYPE_FQDN:
1382                 if ((V_icmp6_nodeinfo & ICMP6_NODEINFO_FQDNOK) == 0)
1383                         goto bad;
1384                 break;
1385         case NI_QTYPE_NODEADDR:
1386         case NI_QTYPE_IPV4ADDR:
1387                 if ((V_icmp6_nodeinfo & ICMP6_NODEINFO_NODEADDROK) == 0)
1388                         goto bad;
1389                 break;
1390         }
1391
1392         /* guess reply length */
1393         switch (qtype) {
1394         case NI_QTYPE_NOOP:
1395                 break;          /* no reply data */
1396         case NI_QTYPE_SUPTYPES:
1397                 replylen += sizeof(u_int32_t);
1398                 break;
1399         case NI_QTYPE_FQDN:
1400                 /* XXX will append an mbuf */
1401                 replylen += offsetof(struct ni_reply_fqdn, ni_fqdn_namelen);
1402                 break;
1403         case NI_QTYPE_NODEADDR:
1404                 addrs = ni6_addrs(ni6, m, &ifp, (struct in6_addr *)subj);
1405                 if ((replylen += addrs * (sizeof(struct in6_addr) +
1406                     sizeof(u_int32_t))) > MCLBYTES)
1407                         replylen = MCLBYTES; /* XXX: will truncate pkt later */
1408                 break;
1409         case NI_QTYPE_IPV4ADDR:
1410                 /* unsupported - should respond with unknown Qtype? */
1411                 break;
1412         default:
1413                 /*
1414                  * XXX: We must return a reply with the ICMP6 code
1415                  * `unknown Qtype' in this case.  However we regard the case
1416                  * as an FQDN query for backward compatibility.
1417                  * Older versions set a random value to this field,
1418                  * so it rarely varies in the defined qtypes.
1419                  * But the mechanism is not reliable...
1420                  * maybe we should obsolete older versions.
1421                  */
1422                 qtype = NI_QTYPE_FQDN;
1423                 /* XXX will append an mbuf */
1424                 replylen += offsetof(struct ni_reply_fqdn, ni_fqdn_namelen);
1425                 oldfqdn++;
1426                 break;
1427         }
1428
1429         /* Allocate an mbuf to reply. */
1430         if (replylen > MCLBYTES) {
1431                 /*
1432                  * XXX: should we try to allocate more? But MCLBYTES
1433                  * is probably much larger than IPV6_MMTU...
1434                  */
1435                 goto bad;
1436         }
1437         if (replylen > MHLEN)
1438                 n = m_getcl(M_NOWAIT, m->m_type, M_PKTHDR);
1439         else
1440                 n = m_gethdr(M_NOWAIT, m->m_type);
1441         if (n == NULL) {
1442                 m_freem(m);
1443                 return (NULL);
1444         }
1445         m_move_pkthdr(n, m); /* just for recvif and FIB */
1446         n->m_pkthdr.len = n->m_len = replylen;
1447
1448         /* copy mbuf header and IPv6 + Node Information base headers */
1449         bcopy(mtod(m, caddr_t), mtod(n, caddr_t), sizeof(struct ip6_hdr));
1450         nni6 = (struct icmp6_nodeinfo *)(mtod(n, struct ip6_hdr *) + 1);
1451         bcopy((caddr_t)ni6, (caddr_t)nni6, sizeof(struct icmp6_nodeinfo));
1452
1453         /* qtype dependent procedure */
1454         switch (qtype) {
1455         case NI_QTYPE_NOOP:
1456                 nni6->ni_code = ICMP6_NI_SUCCESS;
1457                 nni6->ni_flags = 0;
1458                 break;
1459         case NI_QTYPE_SUPTYPES:
1460         {
1461                 u_int32_t v;
1462                 nni6->ni_code = ICMP6_NI_SUCCESS;
1463                 nni6->ni_flags = htons(0x0000); /* raw bitmap */
1464                 /* supports NOOP, SUPTYPES, FQDN, and NODEADDR */
1465                 v = (u_int32_t)htonl(0x0000000f);
1466                 bcopy(&v, nni6 + 1, sizeof(u_int32_t));
1467                 break;
1468         }
1469         case NI_QTYPE_FQDN:
1470                 nni6->ni_code = ICMP6_NI_SUCCESS;
1471                 fqdn = (struct ni_reply_fqdn *)(mtod(n, caddr_t) +
1472                     sizeof(struct ip6_hdr) + sizeof(struct icmp6_nodeinfo));
1473                 nni6->ni_flags = 0; /* XXX: meaningless TTL */
1474                 fqdn->ni_fqdn_ttl = 0;  /* ditto. */
1475                 /*
1476                  * XXX do we really have FQDN in hostname?
1477                  */
1478                 mtx_lock(&pr->pr_mtx);
1479                 n->m_next = ni6_nametodns(pr->pr_hostname,
1480                     strlen(pr->pr_hostname), oldfqdn);
1481                 mtx_unlock(&pr->pr_mtx);
1482                 if (n->m_next == NULL)
1483                         goto bad;
1484                 /* XXX we assume that n->m_next is not a chain */
1485                 if (n->m_next->m_next != NULL)
1486                         goto bad;
1487                 n->m_pkthdr.len += n->m_next->m_len;
1488                 break;
1489         case NI_QTYPE_NODEADDR:
1490         {
1491                 int lenlim, copied;
1492
1493                 nni6->ni_code = ICMP6_NI_SUCCESS;
1494                 n->m_pkthdr.len = n->m_len =
1495                     sizeof(struct ip6_hdr) + sizeof(struct icmp6_nodeinfo);
1496                 lenlim = M_TRAILINGSPACE(n);
1497                 copied = ni6_store_addrs(ni6, nni6, ifp, lenlim);
1498                 /* XXX: reset mbuf length */
1499                 n->m_pkthdr.len = n->m_len = sizeof(struct ip6_hdr) +
1500                     sizeof(struct icmp6_nodeinfo) + copied;
1501                 break;
1502         }
1503         default:
1504                 break;          /* XXX impossible! */
1505         }
1506
1507         nni6->ni_type = ICMP6_NI_REPLY;
1508         m_freem(m);
1509         return (n);
1510
1511   bad:
1512         m_freem(m);
1513         if (n)
1514                 m_freem(n);
1515         return (NULL);
1516 }
1517
1518 /*
1519  * make a mbuf with DNS-encoded string.  no compression support.
1520  *
1521  * XXX names with less than 2 dots (like "foo" or "foo.section") will be
1522  * treated as truncated name (two \0 at the end).  this is a wild guess.
1523  *
1524  * old - return pascal string if non-zero
1525  */
1526 static struct mbuf *
1527 ni6_nametodns(const char *name, int namelen, int old)
1528 {
1529         struct mbuf *m;
1530         char *cp, *ep;
1531         const char *p, *q;
1532         int i, len, nterm;
1533
1534         if (old)
1535                 len = namelen + 1;
1536         else
1537                 len = MCLBYTES;
1538
1539         /* Because MAXHOSTNAMELEN is usually 256, we use cluster mbuf. */
1540         if (len > MLEN)
1541                 m = m_getcl(M_NOWAIT, MT_DATA, 0);
1542         else
1543                 m = m_get(M_NOWAIT, MT_DATA);
1544         if (m == NULL)
1545                 goto fail;
1546
1547         if (old) {
1548                 m->m_len = len;
1549                 *mtod(m, char *) = namelen;
1550                 bcopy(name, mtod(m, char *) + 1, namelen);
1551                 return m;
1552         } else {
1553                 m->m_len = 0;
1554                 cp = mtod(m, char *);
1555                 ep = mtod(m, char *) + M_TRAILINGSPACE(m);
1556
1557                 /* if not certain about my name, return empty buffer */
1558                 if (namelen == 0)
1559                         return m;
1560
1561                 /*
1562                  * guess if it looks like shortened hostname, or FQDN.
1563                  * shortened hostname needs two trailing "\0".
1564                  */
1565                 i = 0;
1566                 for (p = name; p < name + namelen; p++) {
1567                         if (*p && *p == '.')
1568                                 i++;
1569                 }
1570                 if (i < 2)
1571                         nterm = 2;
1572                 else
1573                         nterm = 1;
1574
1575                 p = name;
1576                 while (cp < ep && p < name + namelen) {
1577                         i = 0;
1578                         for (q = p; q < name + namelen && *q && *q != '.'; q++)
1579                                 i++;
1580                         /* result does not fit into mbuf */
1581                         if (cp + i + 1 >= ep)
1582                                 goto fail;
1583                         /*
1584                          * DNS label length restriction, RFC1035 page 8.
1585                          * "i == 0" case is included here to avoid returning
1586                          * 0-length label on "foo..bar".
1587                          */
1588                         if (i <= 0 || i >= 64)
1589                                 goto fail;
1590                         *cp++ = i;
1591                         bcopy(p, cp, i);
1592                         cp += i;
1593                         p = q;
1594                         if (p < name + namelen && *p == '.')
1595                                 p++;
1596                 }
1597                 /* termination */
1598                 if (cp + nterm >= ep)
1599                         goto fail;
1600                 while (nterm-- > 0)
1601                         *cp++ = '\0';
1602                 m->m_len = cp - mtod(m, char *);
1603                 return m;
1604         }
1605
1606         panic("should not reach here");
1607         /* NOTREACHED */
1608
1609  fail:
1610         if (m)
1611                 m_freem(m);
1612         return NULL;
1613 }
1614
1615 /*
1616  * check if two DNS-encoded string matches.  takes care of truncated
1617  * form (with \0\0 at the end).  no compression support.
1618  * XXX upper/lowercase match (see RFC2065)
1619  */
1620 static int
1621 ni6_dnsmatch(const char *a, int alen, const char *b, int blen)
1622 {
1623         const char *a0, *b0;
1624         int l;
1625
1626         /* simplest case - need validation? */
1627         if (alen == blen && bcmp(a, b, alen) == 0)
1628                 return 1;
1629
1630         a0 = a;
1631         b0 = b;
1632
1633         /* termination is mandatory */
1634         if (alen < 2 || blen < 2)
1635                 return 0;
1636         if (a0[alen - 1] != '\0' || b0[blen - 1] != '\0')
1637                 return 0;
1638         alen--;
1639         blen--;
1640
1641         while (a - a0 < alen && b - b0 < blen) {
1642                 if (a - a0 + 1 > alen || b - b0 + 1 > blen)
1643                         return 0;
1644
1645                 if ((signed char)a[0] < 0 || (signed char)b[0] < 0)
1646                         return 0;
1647                 /* we don't support compression yet */
1648                 if (a[0] >= 64 || b[0] >= 64)
1649                         return 0;
1650
1651                 /* truncated case */
1652                 if (a[0] == 0 && a - a0 == alen - 1)
1653                         return 1;
1654                 if (b[0] == 0 && b - b0 == blen - 1)
1655                         return 1;
1656                 if (a[0] == 0 || b[0] == 0)
1657                         return 0;
1658
1659                 if (a[0] != b[0])
1660                         return 0;
1661                 l = a[0];
1662                 if (a - a0 + 1 + l > alen || b - b0 + 1 + l > blen)
1663                         return 0;
1664                 if (bcmp(a + 1, b + 1, l) != 0)
1665                         return 0;
1666
1667                 a += 1 + l;
1668                 b += 1 + l;
1669         }
1670
1671         if (a - a0 == alen && b - b0 == blen)
1672                 return 1;
1673         else
1674                 return 0;
1675 }
1676
1677 /*
1678  * calculate the number of addresses to be returned in the node info reply.
1679  */
1680 static int
1681 ni6_addrs(struct icmp6_nodeinfo *ni6, struct mbuf *m, struct ifnet **ifpp,
1682     struct in6_addr *subj)
1683 {
1684         struct ifnet *ifp;
1685         struct in6_ifaddr *ifa6;
1686         struct ifaddr *ifa;
1687         int addrs = 0, addrsofif, iffound = 0;
1688         int niflags = ni6->ni_flags;
1689
1690         NET_EPOCH_ASSERT();
1691
1692         if ((niflags & NI_NODEADDR_FLAG_ALL) == 0) {
1693                 switch (ni6->ni_code) {
1694                 case ICMP6_NI_SUBJ_IPV6:
1695                         if (subj == NULL) /* must be impossible... */
1696                                 return (0);
1697                         break;
1698                 default:
1699                         /*
1700                          * XXX: we only support IPv6 subject address for
1701                          * this Qtype.
1702                          */
1703                         return (0);
1704                 }
1705         }
1706
1707         CK_STAILQ_FOREACH(ifp, &V_ifnet, if_link) {
1708                 addrsofif = 0;
1709                 CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
1710                         if (ifa->ifa_addr->sa_family != AF_INET6)
1711                                 continue;
1712                         ifa6 = (struct in6_ifaddr *)ifa;
1713
1714                         if ((niflags & NI_NODEADDR_FLAG_ALL) == 0 &&
1715                             IN6_ARE_ADDR_EQUAL(subj, &ifa6->ia_addr.sin6_addr))
1716                                 iffound = 1;
1717
1718                         /*
1719                          * IPv4-mapped addresses can only be returned by a
1720                          * Node Information proxy, since they represent
1721                          * addresses of IPv4-only nodes, which perforce do
1722                          * not implement this protocol.
1723                          * [icmp-name-lookups-07, Section 5.4]
1724                          * So we don't support NI_NODEADDR_FLAG_COMPAT in
1725                          * this function at this moment.
1726                          */
1727
1728                         /* What do we have to do about ::1? */
1729                         switch (in6_addrscope(&ifa6->ia_addr.sin6_addr)) {
1730                         case IPV6_ADDR_SCOPE_LINKLOCAL:
1731                                 if ((niflags & NI_NODEADDR_FLAG_LINKLOCAL) == 0)
1732                                         continue;
1733                                 break;
1734                         case IPV6_ADDR_SCOPE_SITELOCAL:
1735                                 if ((niflags & NI_NODEADDR_FLAG_SITELOCAL) == 0)
1736                                         continue;
1737                                 break;
1738                         case IPV6_ADDR_SCOPE_GLOBAL:
1739                                 if ((niflags & NI_NODEADDR_FLAG_GLOBAL) == 0)
1740                                         continue;
1741                                 break;
1742                         default:
1743                                 continue;
1744                         }
1745
1746                         /*
1747                          * check if anycast is okay.
1748                          * XXX: just experimental.  not in the spec.
1749                          */
1750                         if ((ifa6->ia6_flags & IN6_IFF_ANYCAST) != 0 &&
1751                             (niflags & NI_NODEADDR_FLAG_ANYCAST) == 0)
1752                                 continue; /* we need only unicast addresses */
1753                         if ((ifa6->ia6_flags & IN6_IFF_TEMPORARY) != 0 &&
1754                             (V_icmp6_nodeinfo & ICMP6_NODEINFO_TMPADDROK) == 0) {
1755                                 continue;
1756                         }
1757                         addrsofif++; /* count the address */
1758                 }
1759                 if (iffound) {
1760                         *ifpp = ifp;
1761                         return (addrsofif);
1762                 }
1763
1764                 addrs += addrsofif;
1765         }
1766
1767         return (addrs);
1768 }
1769
1770 static int
1771 ni6_store_addrs(struct icmp6_nodeinfo *ni6, struct icmp6_nodeinfo *nni6,
1772     struct ifnet *ifp0, int resid)
1773 {
1774         struct ifnet *ifp;
1775         struct in6_ifaddr *ifa6;
1776         struct ifaddr *ifa;
1777         struct ifnet *ifp_dep = NULL;
1778         int copied = 0, allow_deprecated = 0;
1779         u_char *cp = (u_char *)(nni6 + 1);
1780         int niflags = ni6->ni_flags;
1781         u_int32_t ltime;
1782
1783         NET_EPOCH_ASSERT();
1784
1785         if (ifp0 == NULL && !(niflags & NI_NODEADDR_FLAG_ALL))
1786                 return (0);     /* needless to copy */
1787
1788         ifp = ifp0 ? ifp0 : CK_STAILQ_FIRST(&V_ifnet);
1789   again:
1790
1791         for (; ifp; ifp = CK_STAILQ_NEXT(ifp, if_link)) {
1792                 CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
1793                         if (ifa->ifa_addr->sa_family != AF_INET6)
1794                                 continue;
1795                         ifa6 = (struct in6_ifaddr *)ifa;
1796
1797                         if ((ifa6->ia6_flags & IN6_IFF_DEPRECATED) != 0 &&
1798                             allow_deprecated == 0) {
1799                                 /*
1800                                  * prefererred address should be put before
1801                                  * deprecated addresses.
1802                                  */
1803
1804                                 /* record the interface for later search */
1805                                 if (ifp_dep == NULL)
1806                                         ifp_dep = ifp;
1807
1808                                 continue;
1809                         } else if ((ifa6->ia6_flags & IN6_IFF_DEPRECATED) == 0 &&
1810                             allow_deprecated != 0)
1811                                 continue; /* we now collect deprecated addrs */
1812
1813                         /* What do we have to do about ::1? */
1814                         switch (in6_addrscope(&ifa6->ia_addr.sin6_addr)) {
1815                         case IPV6_ADDR_SCOPE_LINKLOCAL:
1816                                 if ((niflags & NI_NODEADDR_FLAG_LINKLOCAL) == 0)
1817                                         continue;
1818                                 break;
1819                         case IPV6_ADDR_SCOPE_SITELOCAL:
1820                                 if ((niflags & NI_NODEADDR_FLAG_SITELOCAL) == 0)
1821                                         continue;
1822                                 break;
1823                         case IPV6_ADDR_SCOPE_GLOBAL:
1824                                 if ((niflags & NI_NODEADDR_FLAG_GLOBAL) == 0)
1825                                         continue;
1826                                 break;
1827                         default:
1828                                 continue;
1829                         }
1830
1831                         /*
1832                          * check if anycast is okay.
1833                          * XXX: just experimental.  not in the spec.
1834                          */
1835                         if ((ifa6->ia6_flags & IN6_IFF_ANYCAST) != 0 &&
1836                             (niflags & NI_NODEADDR_FLAG_ANYCAST) == 0)
1837                                 continue;
1838                         if ((ifa6->ia6_flags & IN6_IFF_TEMPORARY) != 0 &&
1839                             (V_icmp6_nodeinfo & ICMP6_NODEINFO_TMPADDROK) == 0) {
1840                                 continue;
1841                         }
1842
1843                         /* now we can copy the address */
1844                         if (resid < sizeof(struct in6_addr) +
1845                             sizeof(u_int32_t)) {
1846                                 /*
1847                                  * We give up much more copy.
1848                                  * Set the truncate flag and return.
1849                                  */
1850                                 nni6->ni_flags |= NI_NODEADDR_FLAG_TRUNCATE;
1851                                 return (copied);
1852                         }
1853
1854                         /*
1855                          * Set the TTL of the address.
1856                          * The TTL value should be one of the following
1857                          * according to the specification:
1858                          *
1859                          * 1. The remaining lifetime of a DHCP lease on the
1860                          *    address, or
1861                          * 2. The remaining Valid Lifetime of a prefix from
1862                          *    which the address was derived through Stateless
1863                          *    Autoconfiguration.
1864                          *
1865                          * Note that we currently do not support stateful
1866                          * address configuration by DHCPv6, so the former
1867                          * case can't happen.
1868                          */
1869                         if (ifa6->ia6_lifetime.ia6t_expire == 0)
1870                                 ltime = ND6_INFINITE_LIFETIME;
1871                         else {
1872                                 if (ifa6->ia6_lifetime.ia6t_expire >
1873                                     time_uptime)
1874                                         ltime = htonl(ifa6->ia6_lifetime.ia6t_expire - time_uptime);
1875                                 else
1876                                         ltime = 0;
1877                         }
1878
1879                         bcopy(&ltime, cp, sizeof(u_int32_t));
1880                         cp += sizeof(u_int32_t);
1881
1882                         /* copy the address itself */
1883                         bcopy(&ifa6->ia_addr.sin6_addr, cp,
1884                             sizeof(struct in6_addr));
1885                         in6_clearscope((struct in6_addr *)cp); /* XXX */
1886                         cp += sizeof(struct in6_addr);
1887
1888                         resid -= (sizeof(struct in6_addr) + sizeof(u_int32_t));
1889                         copied += (sizeof(struct in6_addr) + sizeof(u_int32_t));
1890                 }
1891                 if (ifp0)       /* we need search only on the specified IF */
1892                         break;
1893         }
1894
1895         if (allow_deprecated == 0 && ifp_dep != NULL) {
1896                 ifp = ifp_dep;
1897                 allow_deprecated = 1;
1898
1899                 goto again;
1900         }
1901
1902         return (copied);
1903 }
1904
1905 static bool
1906 icmp6_rip6_match(const struct inpcb *inp, void *v)
1907 {
1908         struct ip6_hdr *ip6 = v;
1909
1910         if ((inp->inp_vflag & INP_IPV6) == 0)
1911                 return (false);
1912         if (inp->inp_ip_p != IPPROTO_ICMPV6)
1913                 return (false);
1914         if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr) &&
1915            !IN6_ARE_ADDR_EQUAL(&inp->in6p_laddr, &ip6->ip6_dst))
1916                 return (false);
1917         if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr) &&
1918            !IN6_ARE_ADDR_EQUAL(&inp->in6p_faddr, &ip6->ip6_src))
1919                 return (false);
1920         return (true);
1921 }
1922
1923 /*
1924  * XXX almost dup'ed code with rip6_input.
1925  */
1926 static int
1927 icmp6_rip6_input(struct mbuf **mp, int off)
1928 {
1929         struct mbuf *n, *m = *mp;
1930         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
1931         struct inpcb_iterator inpi = INP_ITERATOR(&V_ripcbinfo,
1932             INPLOOKUP_RLOCKPCB, icmp6_rip6_match, ip6);
1933         struct inpcb *inp;
1934         struct sockaddr_in6 fromsa;
1935         struct icmp6_hdr *icmp6;
1936         struct mbuf *opts = NULL;
1937         int delivered = 0;
1938
1939         /* This is assumed to be safe; icmp6_input() does a pullup. */
1940         icmp6 = (struct icmp6_hdr *)((caddr_t)ip6 + off);
1941
1942         /*
1943          * XXX: the address may have embedded scope zone ID, which should be
1944          * hidden from applications.
1945          */
1946         bzero(&fromsa, sizeof(fromsa));
1947         fromsa.sin6_family = AF_INET6;
1948         fromsa.sin6_len = sizeof(struct sockaddr_in6);
1949         fromsa.sin6_addr = ip6->ip6_src;
1950         if (sa6_recoverscope(&fromsa)) {
1951                 m_freem(m);
1952                 *mp = NULL;
1953                 return (IPPROTO_DONE);
1954         }
1955
1956         while ((inp = inp_next(&inpi)) != NULL) {
1957                 if (ICMP6_FILTER_WILLBLOCK(icmp6->icmp6_type,
1958                     inp->in6p_icmp6filt))
1959                         continue;
1960                 /*
1961                  * Recent network drivers tend to allocate a single
1962                  * mbuf cluster, rather than to make a couple of
1963                  * mbufs without clusters.  Also, since the IPv6 code
1964                  * path tries to avoid m_pullup(), it is highly
1965                  * probable that we still have an mbuf cluster here
1966                  * even though the necessary length can be stored in an
1967                  * mbuf's internal buffer.
1968                  * Meanwhile, the default size of the receive socket
1969                  * buffer for raw sockets is not so large.  This means
1970                  * the possibility of packet loss is relatively higher
1971                  * than before.  To avoid this scenario, we copy the
1972                  * received data to a separate mbuf that does not use
1973                  * a cluster, if possible.
1974                  * XXX: it is better to copy the data after stripping
1975                  * intermediate headers.
1976                  */
1977                 if ((m->m_flags & M_EXT) && m->m_next == NULL &&
1978                     m->m_len <= MHLEN) {
1979                         n = m_get(M_NOWAIT, m->m_type);
1980                         if (n != NULL) {
1981                                 if (m_dup_pkthdr(n, m, M_NOWAIT)) {
1982                                         bcopy(m->m_data, n->m_data, m->m_len);
1983                                         n->m_len = m->m_len;
1984                                 } else {
1985                                         m_free(n);
1986                                         n = NULL;
1987                                 }
1988                         }
1989                 } else
1990                         n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
1991                 if (n == NULL)
1992                         continue;
1993                 if (inp->inp_flags & INP_CONTROLOPTS)
1994                         ip6_savecontrol(inp, n, &opts);
1995                 /* strip intermediate headers */
1996                 m_adj(n, off);
1997                 SOCKBUF_LOCK(&inp->inp_socket->so_rcv);
1998                 if (sbappendaddr_locked(&inp->inp_socket->so_rcv,
1999                     (struct sockaddr *)&fromsa, n, opts) == 0) {
2000                         soroverflow_locked(inp->inp_socket);
2001                         m_freem(n);
2002                         if (opts)
2003                                 m_freem(opts);
2004                 } else {
2005                         sorwakeup_locked(inp->inp_socket);
2006                         delivered++;
2007                 }
2008                 opts = NULL;
2009         }
2010         m_freem(m);
2011         *mp = NULL;
2012         if (delivered == 0)
2013                 IP6STAT_DEC(ip6s_delivered);
2014         return (IPPROTO_DONE);
2015 }
2016
2017 /*
2018  * Reflect the ip6 packet back to the source.
2019  * OFF points to the icmp6 header, counted from the top of the mbuf.
2020  */
2021 static void
2022 icmp6_reflect(struct mbuf *m, size_t off)
2023 {
2024         struct in6_addr src6, *srcp;
2025         struct ip6_hdr *ip6;
2026         struct icmp6_hdr *icmp6;
2027         struct in6_ifaddr *ia = NULL;
2028         struct ifnet *outif = NULL;
2029         int plen;
2030         int type, code, hlim;
2031
2032         /* too short to reflect */
2033         if (off < sizeof(struct ip6_hdr)) {
2034                 nd6log((LOG_DEBUG,
2035                     "sanity fail: off=%lx, sizeof(ip6)=%lx in %s:%d\n",
2036                     (u_long)off, (u_long)sizeof(struct ip6_hdr),
2037                     __FILE__, __LINE__));
2038                 goto bad;
2039         }
2040
2041         /*
2042          * If there are extra headers between IPv6 and ICMPv6, strip
2043          * off that header first.
2044          */
2045 #ifdef DIAGNOSTIC
2046         if (sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr) > MHLEN)
2047                 panic("assumption failed in icmp6_reflect");
2048 #endif
2049         if (off > sizeof(struct ip6_hdr)) {
2050                 size_t l;
2051                 struct ip6_hdr nip6;
2052
2053                 l = off - sizeof(struct ip6_hdr);
2054                 m_copydata(m, 0, sizeof(nip6), (caddr_t)&nip6);
2055                 m_adj(m, l);
2056                 l = sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr);
2057                 if (m->m_len < l) {
2058                         if ((m = m_pullup(m, l)) == NULL)
2059                                 return;
2060                 }
2061                 bcopy((caddr_t)&nip6, mtod(m, caddr_t), sizeof(nip6));
2062         } else /* off == sizeof(struct ip6_hdr) */ {
2063                 size_t l;
2064                 l = sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr);
2065                 if (m->m_len < l) {
2066                         if ((m = m_pullup(m, l)) == NULL)
2067                                 return;
2068                 }
2069         }
2070         plen = m->m_pkthdr.len - sizeof(struct ip6_hdr);
2071         ip6 = mtod(m, struct ip6_hdr *);
2072         ip6->ip6_nxt = IPPROTO_ICMPV6;
2073         icmp6 = (struct icmp6_hdr *)(ip6 + 1);
2074         type = icmp6->icmp6_type; /* keep type for statistics */
2075         code = icmp6->icmp6_code; /* ditto. */
2076         hlim = 0;
2077         srcp = NULL;
2078
2079         /*
2080          * If the incoming packet was addressed directly to us (i.e. unicast),
2081          * use dst as the src for the reply.
2082          * The IN6_IFF_NOTREADY case should be VERY rare, but is possible
2083          * (for example) when we encounter an error while forwarding procedure
2084          * destined to a duplicated address of ours.
2085          */
2086         if (!IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
2087                 ia = in6ifa_ifwithaddr(&ip6->ip6_dst, 0 /* XXX */, false);
2088                 if (ia != NULL && !(ia->ia6_flags &
2089                     (IN6_IFF_ANYCAST|IN6_IFF_NOTREADY))) {
2090                         src6 = ia->ia_addr.sin6_addr;
2091                         srcp = &src6;
2092
2093                         if (m->m_pkthdr.rcvif != NULL) {
2094                                 /* XXX: This may not be the outgoing interface */
2095                                 hlim = ND_IFINFO(m->m_pkthdr.rcvif)->chlim;
2096                         } else
2097                                 hlim = V_ip6_defhlim;
2098                 }
2099         }
2100
2101         if (srcp == NULL) {
2102                 int error;
2103                 struct in6_addr dst6;
2104                 uint32_t scopeid;
2105
2106                 /*
2107                  * This case matches to multicasts, our anycast, or unicasts
2108                  * that we do not own.  Select a source address based on the
2109                  * source address of the erroneous packet.
2110                  */
2111                 in6_splitscope(&ip6->ip6_src, &dst6, &scopeid);
2112                 error = in6_selectsrc_addr(M_GETFIB(m), &dst6,
2113                     scopeid, NULL, &src6, &hlim);
2114
2115                 if (error) {
2116                         char ip6buf[INET6_ADDRSTRLEN];
2117                         nd6log((LOG_DEBUG,
2118                             "icmp6_reflect: source can't be determined: "
2119                             "dst=%s, error=%d\n",
2120                             ip6_sprintf(ip6buf, &ip6->ip6_dst), error));
2121                         goto bad;
2122                 }
2123                 srcp = &src6;
2124         }
2125         /*
2126          * ip6_input() drops a packet if its src is multicast.
2127          * So, the src is never multicast.
2128          */
2129         ip6->ip6_dst = ip6->ip6_src;
2130         ip6->ip6_src = *srcp;
2131         ip6->ip6_flow = 0;
2132         ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
2133         ip6->ip6_vfc |= IPV6_VERSION;
2134         ip6->ip6_nxt = IPPROTO_ICMPV6;
2135         ip6->ip6_hlim = hlim;
2136
2137         icmp6->icmp6_cksum = 0;
2138         icmp6->icmp6_cksum = in6_cksum(m, IPPROTO_ICMPV6,
2139             sizeof(struct ip6_hdr), plen);
2140
2141         /*
2142          * XXX option handling
2143          */
2144
2145         m->m_flags &= ~(M_BCAST|M_MCAST);
2146         m->m_pkthdr.rcvif = NULL;
2147         ip6_output(m, NULL, NULL, 0, NULL, &outif, NULL);
2148         if (outif)
2149                 icmp6_ifoutstat_inc(outif, type, code);
2150
2151         return;
2152
2153  bad:
2154         m_freem(m);
2155         return;
2156 }
2157
2158 static const char *
2159 icmp6_redirect_diag(struct in6_addr *src6, struct in6_addr *dst6,
2160     struct in6_addr *tgt6)
2161 {
2162         static char buf[1024];
2163         char ip6bufs[INET6_ADDRSTRLEN];
2164         char ip6bufd[INET6_ADDRSTRLEN];
2165         char ip6buft[INET6_ADDRSTRLEN];
2166         snprintf(buf, sizeof(buf), "(src=%s dst=%s tgt=%s)",
2167             ip6_sprintf(ip6bufs, src6), ip6_sprintf(ip6bufd, dst6),
2168             ip6_sprintf(ip6buft, tgt6));
2169         return buf;
2170 }
2171
2172 void
2173 icmp6_redirect_input(struct mbuf *m, int off)
2174 {
2175         struct ifnet *ifp;
2176         struct ip6_hdr *ip6;
2177         struct nd_redirect *nd_rd;
2178         struct in6_addr src6, redtgt6, reddst6;
2179         union nd_opts ndopts;
2180         char ip6buf[INET6_ADDRSTRLEN];
2181         char *lladdr;
2182         int icmp6len, is_onlink, is_router, lladdrlen;
2183
2184         M_ASSERTPKTHDR(m);
2185         KASSERT(m->m_pkthdr.rcvif != NULL, ("%s: no rcvif", __func__));
2186
2187         /* XXX if we are router, we don't update route by icmp6 redirect */
2188         if (V_ip6_forwarding)
2189                 goto freeit;
2190         if (!V_icmp6_rediraccept)
2191                 goto freeit;
2192
2193         /* RFC 6980: Nodes MUST silently ignore fragments */
2194         if(m->m_flags & M_FRAGMENTED)
2195                 goto freeit;
2196
2197         ip6 = mtod(m, struct ip6_hdr *);
2198         icmp6len = ntohs(ip6->ip6_plen);
2199         if (m->m_len < off + icmp6len) {
2200                 m = m_pullup(m, off + icmp6len);
2201                 if (m == NULL) {
2202                         IP6STAT_INC(ip6s_exthdrtoolong);
2203                         return;
2204                 }
2205         }
2206         ip6 = mtod(m, struct ip6_hdr *);
2207         nd_rd = (struct nd_redirect *)((caddr_t)ip6 + off);
2208
2209         ifp = m->m_pkthdr.rcvif;
2210         redtgt6 = nd_rd->nd_rd_target;
2211         reddst6 = nd_rd->nd_rd_dst;
2212
2213         if (in6_setscope(&redtgt6, ifp, NULL) ||
2214             in6_setscope(&reddst6, ifp, NULL)) {
2215                 goto freeit;
2216         }
2217
2218         /* validation */
2219         src6 = ip6->ip6_src;
2220         if (!IN6_IS_ADDR_LINKLOCAL(&src6)) {
2221                 nd6log((LOG_ERR,
2222                     "ICMP6 redirect sent from %s rejected; "
2223                     "must be from linklocal\n",
2224                     ip6_sprintf(ip6buf, &src6)));
2225                 goto bad;
2226         }
2227         if (__predict_false(ip6->ip6_hlim != 255)) {
2228                 ICMP6STAT_INC(icp6s_invlhlim);
2229                 nd6log((LOG_ERR,
2230                     "ICMP6 redirect sent from %s rejected; "
2231                     "hlim=%d (must be 255)\n",
2232                     ip6_sprintf(ip6buf, &src6), ip6->ip6_hlim));
2233                 goto bad;
2234         }
2235     {
2236         /* ip6->ip6_src must be equal to gw for icmp6->icmp6_reddst */
2237         struct nhop_object *nh;
2238         struct in6_addr kdst;
2239         uint32_t scopeid;
2240
2241         in6_splitscope(&reddst6, &kdst, &scopeid);
2242         NET_EPOCH_ASSERT();
2243         nh = fib6_lookup(ifp->if_fib, &kdst, scopeid, 0, 0);
2244         if (nh != NULL) {
2245                 struct in6_addr nh_addr;
2246                 nh_addr = ifatoia6(nh->nh_ifa)->ia_addr.sin6_addr;
2247                 if ((nh->nh_flags & NHF_GATEWAY) == 0) {
2248                         nd6log((LOG_ERR,
2249                             "ICMP6 redirect rejected; no route "
2250                             "with inet6 gateway found for redirect dst: %s\n",
2251                             icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2252                         goto bad;
2253                 }
2254
2255                 /*
2256                  * Embed scope zone id into next hop address.
2257                  */
2258                 nh_addr = nh->gw6_sa.sin6_addr;
2259
2260                 if (IN6_ARE_ADDR_EQUAL(&src6, &nh_addr) == 0) {
2261                         nd6log((LOG_ERR,
2262                             "ICMP6 redirect rejected; "
2263                             "not equal to gw-for-src=%s (must be same): "
2264                             "%s\n",
2265                             ip6_sprintf(ip6buf, &nh_addr),
2266                             icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2267                         goto bad;
2268                 }
2269         } else {
2270                 nd6log((LOG_ERR,
2271                     "ICMP6 redirect rejected; "
2272                     "no route found for redirect dst: %s\n",
2273                     icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2274                 goto bad;
2275         }
2276     }
2277         if (IN6_IS_ADDR_MULTICAST(&reddst6)) {
2278                 nd6log((LOG_ERR,
2279                     "ICMP6 redirect rejected; "
2280                     "redirect dst must be unicast: %s\n",
2281                     icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2282                 goto bad;
2283         }
2284
2285         is_router = is_onlink = 0;
2286         if (IN6_IS_ADDR_LINKLOCAL(&redtgt6))
2287                 is_router = 1;  /* router case */
2288         if (bcmp(&redtgt6, &reddst6, sizeof(redtgt6)) == 0)
2289                 is_onlink = 1;  /* on-link destination case */
2290         if (!is_router && !is_onlink) {
2291                 nd6log((LOG_ERR,
2292                     "ICMP6 redirect rejected; "
2293                     "neither router case nor onlink case: %s\n",
2294                     icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2295                 goto bad;
2296         }
2297
2298         icmp6len -= sizeof(*nd_rd);
2299         nd6_option_init(nd_rd + 1, icmp6len, &ndopts);
2300         if (nd6_options(&ndopts) < 0) {
2301                 nd6log((LOG_INFO, "%s: invalid ND option, rejected: %s\n",
2302                     __func__, icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2303                 /* nd6_options have incremented stats */
2304                 goto freeit;
2305         }
2306
2307         lladdr = NULL;
2308         lladdrlen = 0;
2309         if (ndopts.nd_opts_tgt_lladdr) {
2310                 lladdr = (char *)(ndopts.nd_opts_tgt_lladdr + 1);
2311                 lladdrlen = ndopts.nd_opts_tgt_lladdr->nd_opt_len << 3;
2312         }
2313
2314         if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
2315                 nd6log((LOG_INFO, "%s: lladdrlen mismatch for %s "
2316                     "(if %d, icmp6 packet %d): %s\n",
2317                     __func__, ip6_sprintf(ip6buf, &redtgt6),
2318                     ifp->if_addrlen, lladdrlen - 2,
2319                     icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2320                 goto bad;
2321         }
2322
2323         /* Validation passed. */
2324
2325         /* RFC 2461 8.3 */
2326         nd6_cache_lladdr(ifp, &redtgt6, lladdr, lladdrlen, ND_REDIRECT,
2327             is_onlink ? ND_REDIRECT_ONLINK : ND_REDIRECT_ROUTER);
2328
2329         /*
2330          * Install a gateway route in the better-router case or an interface
2331          * route in the on-link-destination case.
2332          */
2333         {
2334                 struct sockaddr_in6 sdst;
2335                 struct sockaddr_in6 sgw;
2336                 struct sockaddr_in6 ssrc;
2337                 struct sockaddr *gw;
2338                 int rt_flags;
2339                 u_int fibnum;
2340
2341                 bzero(&sdst, sizeof(sdst));
2342                 bzero(&ssrc, sizeof(ssrc));
2343                 sdst.sin6_family = ssrc.sin6_family = AF_INET6;
2344                 sdst.sin6_len = ssrc.sin6_len = sizeof(struct sockaddr_in6);
2345                 bcopy(&reddst6, &sdst.sin6_addr, sizeof(struct in6_addr));
2346                 bcopy(&src6, &ssrc.sin6_addr, sizeof(struct in6_addr));
2347                 rt_flags = 0;
2348                 if (is_router) {
2349                         bzero(&sgw, sizeof(sgw));
2350                         sgw.sin6_family = AF_INET6;
2351                         sgw.sin6_len = sizeof(struct sockaddr_in6);
2352                         bcopy(&redtgt6, &sgw.sin6_addr,
2353                                 sizeof(struct in6_addr));
2354                         gw = (struct sockaddr *)&sgw;
2355                         rt_flags |= RTF_GATEWAY;
2356                 } else
2357                         gw = ifp->if_addr->ifa_addr;
2358                 for (fibnum = 0; fibnum < rt_numfibs; fibnum++)
2359                         rib_add_redirect(fibnum, (struct sockaddr *)&sdst, gw,
2360                             (struct sockaddr *)&ssrc, ifp, rt_flags,
2361                             V_icmp6_redirtimeout);
2362         }
2363
2364  freeit:
2365         m_freem(m);
2366         return;
2367
2368  bad:
2369         ICMP6STAT_INC(icp6s_badredirect);
2370         m_freem(m);
2371 }
2372
2373 void
2374 icmp6_redirect_output(struct mbuf *m0, struct nhop_object *nh)
2375 {
2376         struct ifnet *ifp;      /* my outgoing interface */
2377         struct in6_addr *ifp_ll6;
2378         struct in6_addr *router_ll6;
2379         struct ip6_hdr *sip6;   /* m0 as struct ip6_hdr */
2380         struct mbuf *m = NULL;  /* newly allocated one */
2381         struct m_tag *mtag;
2382         struct ip6_hdr *ip6;    /* m as struct ip6_hdr */
2383         struct nd_redirect *nd_rd;
2384         struct llentry *ln = NULL;
2385         size_t maxlen;
2386         u_char *p;
2387         struct ifnet *outif = NULL;
2388         struct sockaddr_in6 src_sa;
2389
2390         icmp6_errcount(ND_REDIRECT, 0);
2391
2392         /* if we are not router, we don't send icmp6 redirect */
2393         if (!V_ip6_forwarding)
2394                 goto fail;
2395
2396         /* sanity check */
2397         if (!m0 || !nh || !(NH_IS_VALID(nh)) || !(ifp = nh->nh_ifp))
2398                 goto fail;
2399
2400         /*
2401          * Address check:
2402          *  the source address must identify a neighbor, and
2403          *  the destination address must not be a multicast address
2404          *  [RFC 2461, sec 8.2]
2405          */
2406         sip6 = mtod(m0, struct ip6_hdr *);
2407         bzero(&src_sa, sizeof(src_sa));
2408         src_sa.sin6_family = AF_INET6;
2409         src_sa.sin6_len = sizeof(src_sa);
2410         src_sa.sin6_addr = sip6->ip6_src;
2411         if (nd6_is_addr_neighbor(&src_sa, ifp) == 0)
2412                 goto fail;
2413         if (IN6_IS_ADDR_MULTICAST(&sip6->ip6_dst))
2414                 goto fail;      /* what should we do here? */
2415
2416         /* rate limit */
2417         if (icmp6_ratelimit(&sip6->ip6_src, ND_REDIRECT, 0))
2418                 goto fail;
2419
2420         /*
2421          * Since we are going to append up to 1280 bytes (= IPV6_MMTU),
2422          * we almost always ask for an mbuf cluster for simplicity.
2423          * (MHLEN < IPV6_MMTU is almost always true)
2424          */
2425 #if IPV6_MMTU >= MCLBYTES
2426 # error assumption failed about IPV6_MMTU and MCLBYTES
2427 #endif
2428         m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
2429         if (m == NULL)
2430                 goto fail;
2431         M_SETFIB(m, M_GETFIB(m0));
2432         maxlen = M_TRAILINGSPACE(m);
2433         maxlen = min(IPV6_MMTU, maxlen);
2434         /* just for safety */
2435         if (maxlen < sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr) +
2436             ((sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7)) {
2437                 goto fail;
2438         }
2439
2440         {
2441                 /* get ip6 linklocal address for ifp(my outgoing interface). */
2442                 struct in6_ifaddr *ia;
2443                 if ((ia = in6ifa_ifpforlinklocal(ifp,
2444                                                  IN6_IFF_NOTREADY|
2445                                                  IN6_IFF_ANYCAST)) == NULL)
2446                         goto fail;
2447                 ifp_ll6 = &ia->ia_addr.sin6_addr;
2448                 /* XXXRW: reference released prematurely. */
2449                 ifa_free(&ia->ia_ifa);
2450         }
2451
2452         /* get ip6 linklocal address for the router. */
2453         if (nh->nh_flags & NHF_GATEWAY) {
2454                 struct sockaddr_in6 *sin6;
2455                 sin6 = &nh->gw6_sa;
2456                 router_ll6 = &sin6->sin6_addr;
2457                 if (!IN6_IS_ADDR_LINKLOCAL(router_ll6))
2458                         router_ll6 = (struct in6_addr *)NULL;
2459         } else
2460                 router_ll6 = (struct in6_addr *)NULL;
2461
2462         /* ip6 */
2463         ip6 = mtod(m, struct ip6_hdr *);
2464         ip6->ip6_flow = 0;
2465         ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
2466         ip6->ip6_vfc |= IPV6_VERSION;
2467         /* ip6->ip6_plen will be set later */
2468         ip6->ip6_nxt = IPPROTO_ICMPV6;
2469         ip6->ip6_hlim = 255;
2470         /* ip6->ip6_src must be linklocal addr for my outgoing if. */
2471         bcopy(ifp_ll6, &ip6->ip6_src, sizeof(struct in6_addr));
2472         bcopy(&sip6->ip6_src, &ip6->ip6_dst, sizeof(struct in6_addr));
2473
2474         /* ND Redirect */
2475         nd_rd = (struct nd_redirect *)(ip6 + 1);
2476         nd_rd->nd_rd_type = ND_REDIRECT;
2477         nd_rd->nd_rd_code = 0;
2478         nd_rd->nd_rd_reserved = 0;
2479         if (nh->nh_flags & NHF_GATEWAY) {
2480                 /*
2481                  * nd_rd->nd_rd_target must be a link-local address in
2482                  * better router cases.
2483                  */
2484                 if (!router_ll6)
2485                         goto fail;
2486                 bcopy(router_ll6, &nd_rd->nd_rd_target,
2487                     sizeof(nd_rd->nd_rd_target));
2488                 bcopy(&sip6->ip6_dst, &nd_rd->nd_rd_dst,
2489                     sizeof(nd_rd->nd_rd_dst));
2490         } else {
2491                 /* make sure redtgt == reddst */
2492                 bcopy(&sip6->ip6_dst, &nd_rd->nd_rd_target,
2493                     sizeof(nd_rd->nd_rd_target));
2494                 bcopy(&sip6->ip6_dst, &nd_rd->nd_rd_dst,
2495                     sizeof(nd_rd->nd_rd_dst));
2496         }
2497
2498         p = (u_char *)(nd_rd + 1);
2499
2500         if (!router_ll6)
2501                 goto nolladdropt;
2502
2503         {
2504                 /* target lladdr option */
2505                 int len;
2506                 struct nd_opt_hdr *nd_opt;
2507                 char *lladdr;
2508
2509                 ln = nd6_lookup(router_ll6, LLE_SF(AF_INET6,  0), ifp);
2510                 if (ln == NULL)
2511                         goto nolladdropt;
2512
2513                 len = sizeof(*nd_opt) + ifp->if_addrlen;
2514                 len = (len + 7) & ~7;   /* round by 8 */
2515                 /* safety check */
2516                 if (len + (p - (u_char *)ip6) > maxlen)
2517                         goto nolladdropt;
2518
2519                 if (ln->la_flags & LLE_VALID) {
2520                         nd_opt = (struct nd_opt_hdr *)p;
2521                         nd_opt->nd_opt_type = ND_OPT_TARGET_LINKADDR;
2522                         nd_opt->nd_opt_len = len >> 3;
2523                         lladdr = (char *)(nd_opt + 1);
2524                         bcopy(ln->ll_addr, lladdr, ifp->if_addrlen);
2525                         p += len;
2526                 }
2527         }
2528 nolladdropt:
2529         if (ln != NULL)
2530                 LLE_RUNLOCK(ln);
2531
2532         m->m_pkthdr.len = m->m_len = p - (u_char *)ip6;
2533
2534         /* just to be safe */
2535 #ifdef M_DECRYPTED      /*not openbsd*/
2536         if (m0->m_flags & M_DECRYPTED)
2537                 goto noredhdropt;
2538 #endif
2539         if (p - (u_char *)ip6 > maxlen)
2540                 goto noredhdropt;
2541
2542         {
2543                 /* redirected header option */
2544                 int len;
2545                 struct nd_opt_rd_hdr *nd_opt_rh;
2546
2547                 /*
2548                  * compute the maximum size for icmp6 redirect header option.
2549                  * XXX room for auth header?
2550                  */
2551                 len = maxlen - (p - (u_char *)ip6);
2552                 len &= ~7;
2553
2554                 /* This is just for simplicity. */
2555                 if (m0->m_pkthdr.len != m0->m_len) {
2556                         if (m0->m_next) {
2557                                 m_freem(m0->m_next);
2558                                 m0->m_next = NULL;
2559                         }
2560                         m0->m_pkthdr.len = m0->m_len;
2561                 }
2562
2563                 /*
2564                  * Redirected header option spec (RFC2461 4.6.3) talks nothing
2565                  * about padding/truncate rule for the original IP packet.
2566                  * From the discussion on IPv6imp in Feb 1999,
2567                  * the consensus was:
2568                  * - "attach as much as possible" is the goal
2569                  * - pad if not aligned (original size can be guessed by
2570                  *   original ip6 header)
2571                  * Following code adds the padding if it is simple enough,
2572                  * and truncates if not.
2573                  */
2574                 if (m0->m_next || m0->m_pkthdr.len != m0->m_len)
2575                         panic("assumption failed in %s:%d", __FILE__,
2576                             __LINE__);
2577
2578                 if (len - sizeof(*nd_opt_rh) < m0->m_pkthdr.len) {
2579                         /* not enough room, truncate */
2580                         m0->m_pkthdr.len = m0->m_len = len -
2581                             sizeof(*nd_opt_rh);
2582                 } else {
2583                         /* enough room, pad or truncate */
2584                         size_t extra;
2585
2586                         extra = m0->m_pkthdr.len % 8;
2587                         if (extra) {
2588                                 /* pad if easy enough, truncate if not */
2589                                 if (8 - extra <= M_TRAILINGSPACE(m0)) {
2590                                         /* pad */
2591                                         m0->m_len += (8 - extra);
2592                                         m0->m_pkthdr.len += (8 - extra);
2593                                 } else {
2594                                         /* truncate */
2595                                         m0->m_pkthdr.len -= extra;
2596                                         m0->m_len -= extra;
2597                                 }
2598                         }
2599                         len = m0->m_pkthdr.len + sizeof(*nd_opt_rh);
2600                         m0->m_pkthdr.len = m0->m_len = len -
2601                             sizeof(*nd_opt_rh);
2602                 }
2603
2604                 nd_opt_rh = (struct nd_opt_rd_hdr *)p;
2605                 bzero(nd_opt_rh, sizeof(*nd_opt_rh));
2606                 nd_opt_rh->nd_opt_rh_type = ND_OPT_REDIRECTED_HEADER;
2607                 nd_opt_rh->nd_opt_rh_len = len >> 3;
2608                 p += sizeof(*nd_opt_rh);
2609                 m->m_pkthdr.len = m->m_len = p - (u_char *)ip6;
2610
2611                 /* connect m0 to m */
2612                 m_tag_delete_chain(m0, NULL);
2613                 m0->m_flags &= ~M_PKTHDR;
2614                 m->m_next = m0;
2615                 m->m_pkthdr.len = m->m_len + m0->m_len;
2616                 m0 = NULL;
2617         }
2618 noredhdropt:;
2619         if (m0) {
2620                 m_freem(m0);
2621                 m0 = NULL;
2622         }
2623
2624         /* XXX: clear embedded link IDs in the inner header */
2625         in6_clearscope(&sip6->ip6_src);
2626         in6_clearscope(&sip6->ip6_dst);
2627         in6_clearscope(&nd_rd->nd_rd_target);
2628         in6_clearscope(&nd_rd->nd_rd_dst);
2629
2630         ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
2631
2632         nd_rd->nd_rd_cksum = 0;
2633         nd_rd->nd_rd_cksum = in6_cksum(m, IPPROTO_ICMPV6,
2634             sizeof(*ip6), ntohs(ip6->ip6_plen));
2635
2636         if (send_sendso_input_hook != NULL) {
2637                 mtag = m_tag_get(PACKET_TAG_ND_OUTGOING, sizeof(unsigned short),
2638                         M_NOWAIT);
2639                 if (mtag == NULL)
2640                         goto fail;
2641                 *(unsigned short *)(mtag + 1) = nd_rd->nd_rd_type;
2642                 m_tag_prepend(m, mtag);
2643         }
2644
2645         /* send the packet to outside... */
2646         ip6_output(m, NULL, NULL, 0, NULL, &outif, NULL);
2647         if (outif) {
2648                 icmp6_ifstat_inc(outif, ifs6_out_msg);
2649                 icmp6_ifstat_inc(outif, ifs6_out_redirect);
2650         }
2651         ICMP6STAT_INC(icp6s_outhist[ND_REDIRECT]);
2652
2653         return;
2654
2655 fail:
2656         if (m)
2657                 m_freem(m);
2658         if (m0)
2659                 m_freem(m0);
2660 }
2661
2662 /*
2663  * ICMPv6 socket option processing.
2664  */
2665 int
2666 icmp6_ctloutput(struct socket *so, struct sockopt *sopt)
2667 {
2668         int error = 0;
2669         int optlen;
2670         struct inpcb *inp = sotoinpcb(so);
2671         int level, op, optname;
2672
2673         if (sopt) {
2674                 level = sopt->sopt_level;
2675                 op = sopt->sopt_dir;
2676                 optname = sopt->sopt_name;
2677                 optlen = sopt->sopt_valsize;
2678         } else
2679                 level = op = optname = optlen = 0;
2680
2681         if (level != IPPROTO_ICMPV6) {
2682                 return EINVAL;
2683         }
2684
2685         switch (op) {
2686         case PRCO_SETOPT:
2687                 switch (optname) {
2688                 case ICMP6_FILTER:
2689                     {
2690                         struct icmp6_filter ic6f;
2691
2692                         if (optlen != sizeof(ic6f)) {
2693                                 error = EMSGSIZE;
2694                                 break;
2695                         }
2696                         error = sooptcopyin(sopt, &ic6f, optlen, optlen);
2697                         if (error == 0) {
2698                                 INP_WLOCK(inp);
2699                                 *inp->in6p_icmp6filt = ic6f;
2700                                 INP_WUNLOCK(inp);
2701                         }
2702                         break;
2703                     }
2704
2705                 default:
2706                         error = ENOPROTOOPT;
2707                         break;
2708                 }
2709                 break;
2710
2711         case PRCO_GETOPT:
2712                 switch (optname) {
2713                 case ICMP6_FILTER:
2714                     {
2715                         struct icmp6_filter ic6f;
2716
2717                         INP_RLOCK(inp);
2718                         ic6f = *inp->in6p_icmp6filt;
2719                         INP_RUNLOCK(inp);
2720                         error = sooptcopyout(sopt, &ic6f, sizeof(ic6f));
2721                         break;
2722                     }
2723
2724                 default:
2725                         error = ENOPROTOOPT;
2726                         break;
2727                 }
2728                 break;
2729         }
2730
2731         return (error);
2732 }
2733
2734 static int sysctl_icmp6lim_and_jitter(SYSCTL_HANDLER_ARGS);
2735 VNET_DEFINE_STATIC(u_int, icmp6errppslim) = 100;
2736 #define V_icmp6errppslim        VNET(icmp6errppslim)
2737 SYSCTL_PROC(_net_inet6_icmp6, ICMPV6CTL_ERRPPSLIMIT, errppslimit,
2738     CTLTYPE_UINT | CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(icmp6errppslim), 0,
2739     &sysctl_icmp6lim_and_jitter, "IU",
2740     "Maximum number of ICMPv6 error/reply messages per second");
2741
2742 VNET_DEFINE_STATIC(int, icmp6lim_curr_jitter) = 0;
2743 #define V_icmp6lim_curr_jitter  VNET(icmp6lim_curr_jitter)
2744
2745 VNET_DEFINE_STATIC(u_int, icmp6lim_jitter) = 8;
2746 #define V_icmp6lim_jitter       VNET(icmp6lim_jitter)
2747 SYSCTL_PROC(_net_inet6_icmp6, OID_AUTO, icmp6lim_jitter, CTLTYPE_UINT |
2748     CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(icmp6lim_jitter), 0,
2749     &sysctl_icmp6lim_and_jitter, "IU",
2750     "Random errppslimit jitter adjustment limit");
2751
2752 VNET_DEFINE_STATIC(int, icmp6lim_output) = 1;
2753 #define V_icmp6lim_output       VNET(icmp6lim_output)
2754 SYSCTL_INT(_net_inet6_icmp6, OID_AUTO, icmp6lim_output,
2755     CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(icmp6lim_output), 0,
2756     "Enable logging of ICMPv6 response rate limiting");
2757
2758 typedef enum {
2759         RATELIM_PARAM_PROB = 0,
2760         RATELIM_TOO_BIG,
2761         RATELIM_UNREACH,
2762         RATELIM_TEXCEED,
2763         RATELIM_REDIR,
2764         RATELIM_REPLY,
2765         RATELIM_OTHER,
2766         RATELIM_MAX
2767 } ratelim_which;
2768
2769 static const char *icmp6_rate_descrs[RATELIM_MAX] = {
2770         [RATELIM_PARAM_PROB] = "bad IPv6 header",
2771         [RATELIM_TOO_BIG] = "packet too big",
2772         [RATELIM_UNREACH] = "destination unreachable",
2773         [RATELIM_TEXCEED] = "time exceeded",
2774         [RATELIM_REPLY] = "echo reply",
2775         [RATELIM_REDIR] = "neighbor discovery redirect",
2776         [RATELIM_OTHER] = "(other)",
2777 };
2778
2779 static void
2780 icmp6lim_new_jitter(void)
2781 {
2782         /*
2783          * Adjust limit +/- to jitter the measurement to deny a side-channel
2784          * port scan as in https://dl.acm.org/doi/10.1145/3372297.3417280
2785          */
2786         if (V_icmp6lim_jitter > 0)
2787                 V_icmp6lim_curr_jitter =
2788                     arc4random_uniform(V_icmp6lim_jitter * 2 + 1) -
2789                     V_icmp6lim_jitter;
2790 }
2791
2792 static int
2793 sysctl_icmp6lim_and_jitter(SYSCTL_HANDLER_ARGS)
2794 {
2795         uint32_t new;
2796         int error;
2797         bool lim;
2798
2799         MPASS(oidp->oid_arg1 == &VNET_NAME(icmp6errppslim) ||
2800             oidp->oid_arg1 == &VNET_NAME(icmp6lim_jitter));
2801
2802         lim = (oidp->oid_arg1 == &VNET_NAME(icmp6errppslim));
2803         new = lim ? V_icmp6errppslim : V_icmp6lim_jitter;
2804         error = sysctl_handle_int(oidp, &new, 0, req);
2805         if (error == 0 && req->newptr) {
2806                 if (lim) {
2807                         if (new != 0 && new <= V_icmp6lim_jitter)
2808                                 error = EINVAL;
2809                         else
2810                                 V_icmp6errppslim = new;
2811                 } else {
2812                         if (new >= V_icmp6errppslim)
2813                                 error = EINVAL;
2814                         else {
2815                                 V_icmp6lim_jitter = new;
2816                                 icmp6lim_new_jitter();
2817                         }
2818                 }
2819         }
2820         MPASS(V_icmp6errppslim + V_icmp6lim_curr_jitter > 0);
2821
2822         return (error);
2823 }
2824
2825
2826 VNET_DEFINE_STATIC(struct counter_rate, icmp6_rates[RATELIM_MAX]);
2827 #define V_icmp6_rates   VNET(icmp6_rates)
2828
2829 static void
2830 icmp6_ratelimit_init(void)
2831 {
2832
2833         for (int i = 0; i < RATELIM_MAX; i++) {
2834                 V_icmp6_rates[i].cr_rate = counter_u64_alloc(M_WAITOK);
2835                 V_icmp6_rates[i].cr_ticks = ticks;
2836         }
2837         icmp6lim_new_jitter();
2838 }
2839 VNET_SYSINIT(icmp6_ratelimit, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY,
2840     icmp6_ratelimit_init, NULL);
2841
2842 #ifdef VIMAGE
2843 static void
2844 icmp6_ratelimit_uninit(void)
2845 {
2846
2847         for (int i = 0; i < RATELIM_MAX; i++)
2848                 counter_u64_free(V_icmp6_rates[i].cr_rate);
2849 }
2850 VNET_SYSUNINIT(icmp6_ratelimit, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD,
2851     icmp6_ratelimit_uninit, NULL);
2852 #endif
2853
2854 /*
2855  * Perform rate limit check.
2856  * Returns 0 if it is okay to send the icmp6 packet.
2857  * Returns 1 if the router SHOULD NOT send this icmp6 packet due to rate
2858  * limitation.
2859  *
2860  * XXX per-destination/type check necessary?
2861  *
2862  * dst - not used at this moment
2863  * code - not used at this moment
2864  */
2865 int
2866 icmp6_ratelimit(const struct in6_addr *dst, const int type, const int code)
2867 {
2868         ratelim_which which;
2869         int64_t pps;
2870
2871         if (V_icmp6errppslim == 0)
2872                 return (0);
2873
2874         switch (type) {
2875         case ICMP6_PARAM_PROB:
2876                 which = RATELIM_PARAM_PROB;
2877                 break;
2878         case ICMP6_PACKET_TOO_BIG:
2879                 which = RATELIM_TOO_BIG;
2880                 break;
2881         case ICMP6_DST_UNREACH:
2882                 which = RATELIM_UNREACH;
2883                 break;
2884         case ICMP6_TIME_EXCEEDED:
2885                 which = RATELIM_TEXCEED;
2886                 break;
2887         case ND_REDIRECT:
2888                 which = RATELIM_REDIR;
2889                 break;
2890         case ICMP6_ECHO_REPLY:
2891                 which = RATELIM_REPLY;
2892                 break;
2893         default:
2894                 which = RATELIM_OTHER;
2895                 break;
2896         };
2897
2898         pps = counter_ratecheck(&V_icmp6_rates[which], V_icmp6errppslim +
2899             V_icmp6lim_curr_jitter);
2900         if (pps > 0) {
2901                 if (V_icmp6lim_output)
2902                         log(LOG_NOTICE, "Limiting ICMPv6 %s output from %jd "
2903                             "to %d packets/sec\n", icmp6_rate_descrs[which],
2904                             (intmax_t )pps, V_icmp6errppslim +
2905                             V_icmp6lim_curr_jitter);
2906                 icmp6lim_new_jitter();
2907         }
2908         if (pps == -1) {
2909                 ICMP6STAT_INC(icp6s_toofreq);
2910                 return (-1);
2911         }
2912
2913         return (0);
2914 }