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  *      @(#)ip_icmp.c   8.2 (Berkeley) 1/4/94
  63  */
  64
  65 #include <sys/cdefs.h>
  66 __FBSDID("$FreeBSD$");
  67
  68 #define MBUF_PRIVATE    /* XXXRW: Optimisation tries to avoid M_EXT mbufs */
  69
  70 #include "opt_inet.h"
  71 #include "opt_inet6.h"
  72
  73 #include <sys/param.h>
  74 #include <sys/domain.h>
  75 #include <sys/jail.h>
  76 #include <sys/kernel.h>
  77 #include <sys/lock.h>
  78 #include <sys/malloc.h>
  79 #include <sys/mbuf.h>
  80 #include <sys/proc.h>
  81 #include <sys/protosw.h>
  82 #include <sys/signalvar.h>
  83 #include <sys/socket.h>
  84 #include <sys/socketvar.h>
  85 #include <sys/sx.h>
  86 #include <sys/syslog.h>
  87 #include <sys/systm.h>
  88 #include <sys/time.h>
  89
  90 #include <net/if.h>
  91 #include <net/if_var.h>
  92 #include <net/if_dl.h>
  93 #include <net/if_llatbl.h>
  94 #include <net/if_types.h>
  95 #include <net/route.h>
  96 #include <net/route/route_ctl.h>
  97 #include <net/route/nhop.h>
  98 #include <net/vnet.h>
  99
 100 #include <netinet/in.h>
 101 #include <netinet/in_pcb.h>
 102 #include <netinet/in_var.h>
 103 #include <netinet/ip6.h>
 104 #include <netinet/icmp6.h>
 105 #include <netinet/tcp_var.h>
 106
 107 #include <netinet6/in6_fib.h>
 108 #include <netinet6/in6_ifattach.h>
 109 #include <netinet6/in6_pcb.h>
 110 #include <netinet6/ip6protosw.h>
 111 #include <netinet6/ip6_var.h>
 112 #include <netinet6/scope6_var.h>
 113 #include <netinet6/mld6_var.h>
 114 #include <netinet6/nd6.h>
 115 #include <netinet6/send.h>
 116
 117 extern struct domain inet6domain;
 118
 119 VNET_PCPUSTAT_DEFINE(struct icmp6stat, icmp6stat);
 120 VNET_PCPUSTAT_SYSINIT(icmp6stat);
 121
 122 #ifdef VIMAGE
 123 VNET_PCPUSTAT_SYSUNINIT(icmp6stat);
 124 #endif /* VIMAGE */
 125
 126 VNET_DECLARE(struct inpcbinfo, ripcbinfo);
 127 VNET_DECLARE(struct inpcbhead, ripcb);
 128 VNET_DECLARE(int, icmp6errppslim);
 129 VNET_DEFINE_STATIC(int, icmp6errpps_count) = 0;
 130 VNET_DEFINE_STATIC(struct timeval, icmp6errppslim_last);
 131 VNET_DECLARE(int, icmp6_nodeinfo);
 132
 133 #define V_ripcbinfo                     VNET(ripcbinfo)
 134 #define V_ripcb                         VNET(ripcb)
 135 #define V_icmp6errppslim                VNET(icmp6errppslim)
 136 #define V_icmp6errpps_count             VNET(icmp6errpps_count)
 137 #define V_icmp6errppslim_last           VNET(icmp6errppslim_last)
 138 #define V_icmp6_nodeinfo                VNET(icmp6_nodeinfo)
 139
 140 static void icmp6_errcount(int, int);
 141 static int icmp6_rip6_input(struct mbuf **, int);
 142 static void icmp6_reflect(struct mbuf *, size_t);
 143 static int icmp6_ratelimit(const struct in6_addr *, const int, const int);
 144 static const char *icmp6_redirect_diag(struct in6_addr *,
 145         struct in6_addr *, struct in6_addr *);
 146 static struct mbuf *ni6_input(struct mbuf *, int, struct prison *);
 147 static struct mbuf *ni6_nametodns(const char *, int, int);
 148 static int ni6_dnsmatch(const char *, int, const char *, int);
 149 static int ni6_addrs(struct icmp6_nodeinfo *, struct mbuf *,
 150                           struct ifnet **, struct in6_addr *);
 151 static int ni6_store_addrs(struct icmp6_nodeinfo *, struct icmp6_nodeinfo *,
 152                                 struct ifnet *, int);
 153 static int icmp6_notify_error(struct mbuf **, int, int, int);
 154
 155 /*
 156  * Kernel module interface for updating icmp6stat.  The argument is an index
 157  * into icmp6stat treated as an array of u_quad_t.  While this encodes the
 158  * general layout of icmp6stat into the caller, it doesn't encode its
 159  * location, so that future changes to add, for example, per-CPU stats
 160  * support won't cause binary compatibility problems for kernel modules.
 161  */
 162 void
 163 kmod_icmp6stat_inc(int statnum)
 164 {
 165
 166         counter_u64_add(VNET(icmp6stat)[statnum], 1);
 167 }
 168
 169 static void
 170 icmp6_errcount(int type, int code)
 171 {
 172         switch (type) {
 173         case ICMP6_DST_UNREACH:
 174                 switch (code) {
 175                 case ICMP6_DST_UNREACH_NOROUTE:
 176                         ICMP6STAT_INC(icp6s_odst_unreach_noroute);
 177                         return;
 178                 case ICMP6_DST_UNREACH_ADMIN:
 179                         ICMP6STAT_INC(icp6s_odst_unreach_admin);
 180                         return;
 181                 case ICMP6_DST_UNREACH_BEYONDSCOPE:
 182                         ICMP6STAT_INC(icp6s_odst_unreach_beyondscope);
 183                         return;
 184                 case ICMP6_DST_UNREACH_ADDR:
 185                         ICMP6STAT_INC(icp6s_odst_unreach_addr);
 186                         return;
 187                 case ICMP6_DST_UNREACH_NOPORT:
 188                         ICMP6STAT_INC(icp6s_odst_unreach_noport);
 189                         return;
 190                 }
 191                 break;
 192         case ICMP6_PACKET_TOO_BIG:
 193                 ICMP6STAT_INC(icp6s_opacket_too_big);
 194                 return;
 195         case ICMP6_TIME_EXCEEDED:
 196                 switch (code) {
 197                 case ICMP6_TIME_EXCEED_TRANSIT:
 198                         ICMP6STAT_INC(icp6s_otime_exceed_transit);
 199                         return;
 200                 case ICMP6_TIME_EXCEED_REASSEMBLY:
 201                         ICMP6STAT_INC(icp6s_otime_exceed_reassembly);
 202                         return;
 203                 }
 204                 break;
 205         case ICMP6_PARAM_PROB:
 206                 switch (code) {
 207                 case ICMP6_PARAMPROB_HEADER:
 208                         ICMP6STAT_INC(icp6s_oparamprob_header);
 209                         return;
 210                 case ICMP6_PARAMPROB_NEXTHEADER:
 211                         ICMP6STAT_INC(icp6s_oparamprob_nextheader);
 212                         return;
 213                 case ICMP6_PARAMPROB_OPTION:
 214                         ICMP6STAT_INC(icp6s_oparamprob_option);
 215                         return;
 216                 }
 217                 break;
 218         case ND_REDIRECT:
 219                 ICMP6STAT_INC(icp6s_oredirect);
 220                 return;
 221         }
 222         ICMP6STAT_INC(icp6s_ounknown);
 223 }
 224
 225 /*
 226  * A wrapper function for icmp6_error() necessary when the erroneous packet
 227  * may not contain enough scope zone information.
 228  */
 229 void
 230 icmp6_error2(struct mbuf *m, int type, int code, int param,
 231     struct ifnet *ifp)
 232 {
 233         struct ip6_hdr *ip6;
 234
 235         if (ifp == NULL)
 236                 return;
 237
 238         if (m->m_len < sizeof(struct ip6_hdr)) {
 239                 m = m_pullup(m, sizeof(struct ip6_hdr));
 240                 if (m == NULL) {
 241                         IP6STAT_INC(ip6s_exthdrtoolong);
 242                         return;
 243                 }
 244         }
 245         ip6 = mtod(m, struct ip6_hdr *);
 246
 247         if (in6_setscope(&ip6->ip6_src, ifp, NULL) != 0)
 248                 return;
 249         if (in6_setscope(&ip6->ip6_dst, ifp, NULL) != 0)
 250                 return;
 251
 252         icmp6_error(m, type, code, param);
 253 }
 254
 255 /*
 256  * Generate an error packet of type error in response to bad IP6 packet.
 257  */
 258 void
 259 icmp6_error(struct mbuf *m, int type, int code, int param)
 260 {
 261         struct ip6_hdr *oip6, *nip6;
 262         struct icmp6_hdr *icmp6;
 263         u_int preplen;
 264         int off;
 265         int nxt;
 266
 267         ICMP6STAT_INC(icp6s_error);
 268
 269         /* count per-type-code statistics */
 270         icmp6_errcount(type, code);
 271
 272 #ifdef M_DECRYPTED      /*not openbsd*/
 273         if (m->m_flags & M_DECRYPTED) {
 274                 ICMP6STAT_INC(icp6s_canterror);
 275                 goto freeit;
 276         }
 277 #endif
 278
 279         if (m->m_len < sizeof(struct ip6_hdr)) {
 280                 m = m_pullup(m, sizeof(struct ip6_hdr));
 281                 if (m == NULL) {
 282                         IP6STAT_INC(ip6s_exthdrtoolong);
 283                         return;
 284                 }
 285         }
 286         oip6 = mtod(m, struct ip6_hdr *);
 287
 288         /*
 289          * If the destination address of the erroneous packet is a multicast
 290          * address, or the packet was sent using link-layer multicast,
 291          * we should basically suppress sending an error (RFC 2463, Section
 292          * 2.4).
 293          * We have two exceptions (the item e.2 in that section):
 294          * - the Packet Too Big message can be sent for path MTU discovery.
 295          * - the Parameter Problem Message that can be allowed an icmp6 error
 296          *   in the option type field.  This check has been done in
 297          *   ip6_unknown_opt(), so we can just check the type and code.
 298          */
 299         if ((m->m_flags & (M_BCAST|M_MCAST) ||
 300              IN6_IS_ADDR_MULTICAST(&oip6->ip6_dst)) &&
 301             (type != ICMP6_PACKET_TOO_BIG &&
 302              (type != ICMP6_PARAM_PROB ||
 303               code != ICMP6_PARAMPROB_OPTION)))
 304                 goto freeit;
 305
 306         /*
 307          * RFC 2463, 2.4 (e.5): source address check.
 308          * XXX: the case of anycast source?
 309          */
 310         if (IN6_IS_ADDR_UNSPECIFIED(&oip6->ip6_src) ||
 311             IN6_IS_ADDR_MULTICAST(&oip6->ip6_src))
 312                 goto freeit;
 313
 314         /*
 315          * If we are about to send ICMPv6 against ICMPv6 error/redirect,
 316          * don't do it.
 317          */
 318         nxt = -1;
 319         off = ip6_lasthdr(m, 0, IPPROTO_IPV6, &nxt);
 320         if (off >= 0 && nxt == IPPROTO_ICMPV6) {
 321                 struct icmp6_hdr *icp;
 322
 323                 if (m->m_len < off + sizeof(struct icmp6_hdr)) {
 324                         m = m_pullup(m, off + sizeof(struct icmp6_hdr));
 325                         if (m == NULL) {
 326                                 IP6STAT_INC(ip6s_exthdrtoolong);
 327                                 return;
 328                         }
 329                 }
 330                 oip6 = mtod(m, struct ip6_hdr *);
 331                 icp = (struct icmp6_hdr *)(mtod(m, caddr_t) + off);
 332
 333                 if (icp->icmp6_type < ICMP6_ECHO_REQUEST ||
 334                     icp->icmp6_type == ND_REDIRECT) {
 335                         /*
 336                          * ICMPv6 error
 337                          * Special case: for redirect (which is
 338                          * informational) we must not send icmp6 error.
 339                          */
 340                         ICMP6STAT_INC(icp6s_canterror);
 341                         goto freeit;
 342                 } else {
 343                         /* ICMPv6 informational - send the error */
 344                 }
 345         } else {
 346                 /* non-ICMPv6 - send the error */
 347         }
 348
 349         /* Finally, do rate limitation check. */
 350         if (icmp6_ratelimit(&oip6->ip6_src, type, code)) {
 351                 ICMP6STAT_INC(icp6s_toofreq);
 352                 goto freeit;
 353         }
 354
 355         /*
 356          * OK, ICMP6 can be generated.
 357          */
 358
 359         if (m->m_pkthdr.len >= ICMPV6_PLD_MAXLEN)
 360                 m_adj(m, ICMPV6_PLD_MAXLEN - m->m_pkthdr.len);
 361
 362         preplen = sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr);
 363         M_PREPEND(m, preplen, M_NOWAIT);        /* FIB is also copied over. */
 364         if (m == NULL) {
 365                 nd6log((LOG_DEBUG, "ENOBUFS in icmp6_error %d\n", __LINE__));
 366                 return;
 367         }
 368
 369         nip6 = mtod(m, struct ip6_hdr *);
 370         nip6->ip6_src  = oip6->ip6_src;
 371         nip6->ip6_dst  = oip6->ip6_dst;
 372
 373         in6_clearscope(&oip6->ip6_src);
 374         in6_clearscope(&oip6->ip6_dst);
 375
 376         icmp6 = (struct icmp6_hdr *)(nip6 + 1);
 377         icmp6->icmp6_type = type;
 378         icmp6->icmp6_code = code;
 379         icmp6->icmp6_pptr = htonl((u_int32_t)param);
 380
 381         ICMP6STAT_INC(icp6s_outhist[type]);
 382         icmp6_reflect(m, sizeof(struct ip6_hdr)); /* header order: IPv6 - ICMPv6 */
 383
 384         return;
 385
 386   freeit:
 387         /*
 388          * If we can't tell whether or not we can generate ICMP6, free it.
 389          */
 390         m_freem(m);
 391 }
 392
 393 /*
 394  * Process a received ICMP6 message.
 395  */
 396 int
 397 icmp6_input(struct mbuf **mp, int *offp, int proto)
 398 {
 399         struct mbuf *m, *n;
 400         struct ifnet *ifp;
 401         struct ip6_hdr *ip6, *nip6;
 402         struct icmp6_hdr *icmp6, *nicmp6;
 403         char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
 404         int code, error, icmp6len, ip6len, noff, off, sum;
 405
 406         NET_EPOCH_ASSERT();
 407
 408         m = *mp;
 409         off = *offp;
 410
 411         if (m->m_len < off + sizeof(struct icmp6_hdr)) {
 412                 m = m_pullup(m, off + sizeof(struct icmp6_hdr));
 413                 if (m == NULL) {
 414                         IP6STAT_INC(ip6s_exthdrtoolong);
 415                         *mp = m;
 416                         return (IPPROTO_DONE);
 417                 }
 418         }
 419
 420         /*
 421          * Locate icmp6 structure in mbuf, and check
 422          * that not corrupted and of at least minimum length
 423          */
 424
 425         icmp6len = m->m_pkthdr.len - off;
 426         if (icmp6len < sizeof(struct icmp6_hdr)) {
 427                 ICMP6STAT_INC(icp6s_tooshort);
 428                 goto freeit;
 429         }
 430
 431         ip6 = mtod(m, struct ip6_hdr *);
 432         ifp = m->m_pkthdr.rcvif;
 433         /*
 434          * Check multicast group membership.
 435          * Note: SSM filters are not applied for ICMPv6 traffic.
 436          */
 437         if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
 438                 struct in6_multi        *inm;
 439
 440                 inm = in6m_lookup(ifp, &ip6->ip6_dst);
 441                 if (inm == NULL) {
 442                         IP6STAT_INC(ip6s_notmember);
 443                         in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
 444                         goto freeit;
 445                 }
 446         }
 447
 448         /* Calculate the checksum. */
 449         icmp6 = (struct icmp6_hdr *)((caddr_t)ip6 + off);
 450         code = icmp6->icmp6_code;
 451         if ((sum = in6_cksum(m, IPPROTO_ICMPV6, off, icmp6len)) != 0) {
 452                 nd6log((LOG_ERR,
 453                     "ICMP6 checksum error(%d|%x) %s\n",
 454                     icmp6->icmp6_type, sum,
 455                     ip6_sprintf(ip6bufs, &ip6->ip6_src)));
 456                 ICMP6STAT_INC(icp6s_checksum);
 457                 goto freeit;
 458         }
 459
 460         ICMP6STAT_INC(icp6s_inhist[icmp6->icmp6_type]);
 461         icmp6_ifstat_inc(ifp, ifs6_in_msg);
 462         if (icmp6->icmp6_type < ICMP6_INFOMSG_MASK)
 463                 icmp6_ifstat_inc(ifp, ifs6_in_error);
 464
 465         ip6len = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen);
 466         switch (icmp6->icmp6_type) {
 467         case ICMP6_DST_UNREACH:
 468                 icmp6_ifstat_inc(ifp, ifs6_in_dstunreach);
 469                 switch (code) {
 470                 case ICMP6_DST_UNREACH_NOROUTE:
 471                 case ICMP6_DST_UNREACH_ADDR:    /* PRC_HOSTDEAD is a DOS */
 472                         code = PRC_UNREACH_NET;
 473                         break;
 474                 case ICMP6_DST_UNREACH_ADMIN:
 475                         icmp6_ifstat_inc(ifp, ifs6_in_adminprohib);
 476                         code = PRC_UNREACH_ADMIN_PROHIB;
 477                         break;
 478                 case ICMP6_DST_UNREACH_BEYONDSCOPE:
 479                         /* I mean "source address was incorrect." */
 480                         code = PRC_PARAMPROB;
 481                         break;
 482                 case ICMP6_DST_UNREACH_NOPORT:
 483                         code = PRC_UNREACH_PORT;
 484                         break;
 485                 default:
 486                         goto badcode;
 487                 }
 488                 goto deliver;
 489                 break;
 490
 491         case ICMP6_PACKET_TOO_BIG:
 492                 icmp6_ifstat_inc(ifp, ifs6_in_pkttoobig);
 493
 494                 /* validation is made in icmp6_mtudisc_update */
 495
 496                 code = PRC_MSGSIZE;
 497
 498                 /*
 499                  * Updating the path MTU will be done after examining
 500                  * intermediate extension headers.
 501                  */
 502                 goto deliver;
 503                 break;
 504
 505         case ICMP6_TIME_EXCEEDED:
 506                 icmp6_ifstat_inc(ifp, ifs6_in_timeexceed);
 507                 switch (code) {
 508                 case ICMP6_TIME_EXCEED_TRANSIT:
 509                         code = PRC_TIMXCEED_INTRANS;
 510                         break;
 511                 case ICMP6_TIME_EXCEED_REASSEMBLY:
 512                         code = PRC_TIMXCEED_REASS;
 513                         break;
 514                 default:
 515                         goto badcode;
 516                 }
 517                 goto deliver;
 518                 break;
 519
 520         case ICMP6_PARAM_PROB:
 521                 icmp6_ifstat_inc(ifp, ifs6_in_paramprob);
 522                 switch (code) {
 523                 case ICMP6_PARAMPROB_NEXTHEADER:
 524                         code = PRC_UNREACH_PROTOCOL;
 525                         break;
 526                 case ICMP6_PARAMPROB_HEADER:
 527                 case ICMP6_PARAMPROB_OPTION:
 528                         code = PRC_PARAMPROB;
 529                         break;
 530                 default:
 531                         goto badcode;
 532                 }
 533                 goto deliver;
 534                 break;
 535
 536         case ICMP6_ECHO_REQUEST:
 537                 icmp6_ifstat_inc(ifp, ifs6_in_echo);
 538                 if (code != 0)
 539                         goto badcode;
 540                 if ((n = m_copym(m, 0, M_COPYALL, M_NOWAIT)) == NULL) {
 541                         /* Give up remote */
 542                         break;
 543                 }
 544                 if (!M_WRITABLE(n)
 545                  || n->m_len < off + sizeof(struct icmp6_hdr)) {
 546                         struct mbuf *n0 = n;
 547                         int n0len;
 548
 549                         CTASSERT(sizeof(*nip6) + sizeof(*nicmp6) <= MHLEN);
 550                         n = m_gethdr(M_NOWAIT, n0->m_type);
 551                         if (n == NULL) {
 552                                 /* Give up remote */
 553                                 m_freem(n0);
 554                                 break;
 555                         }
 556
 557                         m_move_pkthdr(n, n0);   /* FIB copied. */
 558                         n0len = n0->m_pkthdr.len;       /* save for use below */
 559                         /*
 560                          * Copy IPv6 and ICMPv6 only.
 561                          */
 562                         nip6 = mtod(n, struct ip6_hdr *);
 563                         bcopy(ip6, nip6, sizeof(struct ip6_hdr));
 564                         nicmp6 = (struct icmp6_hdr *)(nip6 + 1);
 565                         bcopy(icmp6, nicmp6, sizeof(struct icmp6_hdr));
 566                         noff = sizeof(struct ip6_hdr);
 567                         /* new mbuf contains only ipv6+icmpv6 headers */
 568                         n->m_len = noff + sizeof(struct icmp6_hdr);
 569                         /*
 570                          * Adjust mbuf.  ip6_plen will be adjusted in
 571                          * ip6_output().
 572                          */
 573                         m_adj(n0, off + sizeof(struct icmp6_hdr));
 574                         /* recalculate complete packet size */
 575                         n->m_pkthdr.len = n0len + (noff - off);
 576                         n->m_next = n0;
 577                 } else {
 578                         if (n->m_len < off + sizeof(*nicmp6)) {
 579                                 n = m_pullup(n, off + sizeof(*nicmp6));
 580                                 if (n == NULL) {
 581                                         IP6STAT_INC(ip6s_exthdrtoolong);
 582                                         break;
 583                                 }
 584                         }
 585                         nicmp6 = (struct icmp6_hdr *)(mtod(n, caddr_t) + off);
 586                         noff = off;
 587                 }
 588                 if (n) {
 589                         nicmp6->icmp6_type = ICMP6_ECHO_REPLY;
 590                         nicmp6->icmp6_code = 0;
 591                         ICMP6STAT_INC(icp6s_reflect);
 592                         ICMP6STAT_INC(icp6s_outhist[ICMP6_ECHO_REPLY]);
 593                         icmp6_reflect(n, noff);
 594                 }
 595                 break;
 596
 597         case ICMP6_ECHO_REPLY:
 598                 icmp6_ifstat_inc(ifp, ifs6_in_echoreply);
 599                 if (code != 0)
 600                         goto badcode;
 601                 break;
 602
 603         case MLD_LISTENER_QUERY:
 604         case MLD_LISTENER_REPORT:
 605         case MLD_LISTENER_DONE:
 606         case MLDV2_LISTENER_REPORT:
 607                 /*
 608                  * Drop MLD traffic which is not link-local, has a hop limit
 609                  * of greater than 1 hop, or which does not have the
 610                  * IPv6 HBH Router Alert option.
 611                  * As IPv6 HBH options are stripped in ip6_input() we must
 612                  * check an mbuf header flag.
 613                  * XXX Should we also sanity check that these messages
 614                  * were directed to a link-local multicast prefix?
 615                  */
 616                 if ((ip6->ip6_hlim != 1) || (m->m_flags & M_RTALERT_MLD) == 0)
 617                         goto freeit;
 618                 if (mld_input(&m, off, icmp6len) != 0) {
 619                         *mp = NULL;
 620                         return (IPPROTO_DONE);
 621                 }
 622                 /* m stays. */
 623                 break;
 624
 625         case ICMP6_WRUREQUEST:  /* ICMP6_FQDN_QUERY */
 626             {
 627                 enum { WRU, FQDN } mode;
 628                 struct prison *pr;
 629
 630                 if (!V_icmp6_nodeinfo)
 631                         break;
 632
 633                 if (icmp6len == sizeof(struct icmp6_hdr) + 4)
 634                         mode = WRU;
 635                 else if (icmp6len >= sizeof(struct icmp6_nodeinfo))
 636                         mode = FQDN;
 637                 else
 638                         goto badlen;
 639
 640                 pr = NULL;
 641                 sx_slock(&allprison_lock);
 642                 TAILQ_FOREACH(pr, &allprison, pr_list)
 643                         if (pr->pr_vnet == ifp->if_vnet)
 644                                 break;
 645                 sx_sunlock(&allprison_lock);
 646                 if (pr == NULL)
 647                         pr = curthread->td_ucred->cr_prison;
 648                 if (mode == FQDN) {
 649                         if (m->m_len < off + sizeof(struct icmp6_nodeinfo)) {
 650                                 m = m_pullup(m, off +
 651                                     sizeof(struct icmp6_nodeinfo));
 652                                 if (m == NULL) {
 653                                         IP6STAT_INC(ip6s_exthdrtoolong);
 654                                         *mp = m;
 655                                         return (IPPROTO_DONE);
 656                                 }
 657                         }
 658                         n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
 659                         if (n)
 660                                 n = ni6_input(n, off, pr);
 661                         /* XXX meaningless if n == NULL */
 662                         noff = sizeof(struct ip6_hdr);
 663                 } else {
 664                         u_char *p;
 665                         int maxhlen, hlen;
 666
 667                         /*
 668                          * XXX: this combination of flags is pointless,
 669                          * but should we keep this for compatibility?
 670                          */
 671                         if ((V_icmp6_nodeinfo & (ICMP6_NODEINFO_FQDNOK |
 672                             ICMP6_NODEINFO_TMPADDROK)) !=
 673                             (ICMP6_NODEINFO_FQDNOK | ICMP6_NODEINFO_TMPADDROK))
 674                                 break;
 675
 676                         if (code != 0)
 677                                 goto badcode;
 678
 679                         CTASSERT(sizeof(*nip6) + sizeof(*nicmp6) + 4 <= MHLEN);
 680                         n = m_gethdr(M_NOWAIT, m->m_type);
 681                         if (n == NULL) {
 682                                 /* Give up remote */
 683                                 break;
 684                         }
 685                         if (!m_dup_pkthdr(n, m, M_NOWAIT)) {
 686                                 /*
 687                                  * Previous code did a blind M_COPY_PKTHDR
 688                                  * and said "just for rcvif".  If true, then
 689                                  * we could tolerate the dup failing (due to
 690                                  * the deep copy of the tag chain).  For now
 691                                  * be conservative and just fail.
 692                                  */
 693                                 m_free(n);
 694                                 n = NULL;
 695                                 break;
 696                         }
 697                         /*
 698                          * Copy IPv6 and ICMPv6 only.
 699                          */
 700                         nip6 = mtod(n, struct ip6_hdr *);
 701                         bcopy(ip6, nip6, sizeof(struct ip6_hdr));
 702                         nicmp6 = (struct icmp6_hdr *)(nip6 + 1);
 703                         bcopy(icmp6, nicmp6, sizeof(struct icmp6_hdr));
 704                         p = (u_char *)(nicmp6 + 1);
 705                         bzero(p, 4);
 706
 707                         maxhlen = M_TRAILINGSPACE(n) -
 708                             (sizeof(*nip6) + sizeof(*nicmp6) + 4);
 709                         mtx_lock(&pr->pr_mtx);
 710                         hlen = strlen(pr->pr_hostname);
 711                         if (maxhlen > hlen)
 712                                 maxhlen = hlen;
 713                         /* meaningless TTL */
 714                         bcopy(pr->pr_hostname, p + 4, maxhlen);
 715                         mtx_unlock(&pr->pr_mtx);
 716                         noff = sizeof(struct ip6_hdr);
 717                         n->m_pkthdr.len = n->m_len = sizeof(struct ip6_hdr) +
 718                                 sizeof(struct icmp6_hdr) + 4 + maxhlen;
 719                         nicmp6->icmp6_type = ICMP6_WRUREPLY;
 720                         nicmp6->icmp6_code = 0;
 721                 }
 722                 if (n) {
 723                         ICMP6STAT_INC(icp6s_reflect);
 724                         ICMP6STAT_INC(icp6s_outhist[ICMP6_WRUREPLY]);
 725                         icmp6_reflect(n, noff);
 726                 }
 727                 break;
 728             }
 729
 730         case ICMP6_WRUREPLY:
 731                 if (code != 0)
 732                         goto badcode;
 733                 break;
 734
 735         case ND_ROUTER_SOLICIT:
 736                 icmp6_ifstat_inc(ifp, ifs6_in_routersolicit);
 737                 if (code != 0)
 738                         goto badcode;
 739                 if (icmp6len < sizeof(struct nd_router_solicit))
 740                         goto badlen;
 741                 if (send_sendso_input_hook != NULL) {
 742                         if (m->m_len < off + icmp6len) {
 743                                 m = m_pullup(m, off + icmp6len);
 744                                 if (m == NULL) {
 745                                         IP6STAT_INC(ip6s_exthdrtoolong);
 746                                         *mp = NULL;
 747                                         return (IPPROTO_DONE);
 748                                 }
 749                         }
 750                         error = send_sendso_input_hook(m, ifp, SND_IN, ip6len);
 751                         if (error == 0) {
 752                                 m = NULL;
 753                                 goto freeit;
 754                         }
 755                 }
 756                 n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
 757                 nd6_rs_input(m, off, icmp6len);
 758                 m = n;
 759                 if (m == NULL)
 760                         goto freeit;
 761                 break;
 762
 763         case ND_ROUTER_ADVERT:
 764                 icmp6_ifstat_inc(ifp, ifs6_in_routeradvert);
 765                 if (code != 0)
 766                         goto badcode;
 767                 if (icmp6len < sizeof(struct nd_router_advert))
 768                         goto badlen;
 769                 if (send_sendso_input_hook != NULL) {
 770                         error = send_sendso_input_hook(m, ifp, SND_IN, ip6len);
 771                         if (error == 0) {
 772                                 m = NULL;
 773                                 goto freeit;
 774                         }
 775                 }
 776                 n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
 777                 nd6_ra_input(m, off, icmp6len);
 778                 m = n;
 779                 if (m == NULL)
 780                         goto freeit;
 781                 break;
 782
 783         case ND_NEIGHBOR_SOLICIT:
 784                 icmp6_ifstat_inc(ifp, ifs6_in_neighborsolicit);
 785                 if (code != 0)
 786                         goto badcode;
 787                 if (icmp6len < sizeof(struct nd_neighbor_solicit))
 788                         goto badlen;
 789                 if (send_sendso_input_hook != NULL) {
 790                         error = send_sendso_input_hook(m, ifp, SND_IN, ip6len);
 791                         if (error == 0) {
 792                                 m = NULL;
 793                                 goto freeit;
 794                         }
 795                 }
 796                 n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
 797                 nd6_ns_input(m, off, icmp6len);
 798                 m = n;
 799                 if (m == NULL)
 800                         goto freeit;
 801                 break;
 802
 803         case ND_NEIGHBOR_ADVERT:
 804                 icmp6_ifstat_inc(ifp, ifs6_in_neighboradvert);
 805                 if (code != 0)
 806                         goto badcode;
 807                 if (icmp6len < sizeof(struct nd_neighbor_advert))
 808                         goto badlen;
 809                 if (send_sendso_input_hook != NULL) {
 810                         error = send_sendso_input_hook(m, ifp, SND_IN, ip6len);
 811                         if (error == 0) {
 812                                 m = NULL;
 813                                 goto freeit;
 814                         }
 815                 }
 816                 n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
 817                 nd6_na_input(m, off, icmp6len);
 818                 m = n;
 819                 if (m == NULL)
 820                         goto freeit;
 821                 break;
 822
 823         case ND_REDIRECT:
 824                 icmp6_ifstat_inc(ifp, ifs6_in_redirect);
 825                 if (code != 0)
 826                         goto badcode;
 827                 if (icmp6len < sizeof(struct nd_redirect))
 828                         goto badlen;
 829                 if (send_sendso_input_hook != NULL) {
 830                         error = send_sendso_input_hook(m, ifp, SND_IN, ip6len);
 831                         if (error == 0) {
 832                                 m = NULL;
 833                                 goto freeit;
 834                         }
 835                 }
 836                 n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
 837                 icmp6_redirect_input(m, off);
 838                 m = n;
 839                 if (m == NULL)
 840                         goto freeit;
 841                 break;
 842
 843         case ICMP6_ROUTER_RENUMBERING:
 844                 if (code != ICMP6_ROUTER_RENUMBERING_COMMAND &&
 845                     code != ICMP6_ROUTER_RENUMBERING_RESULT)
 846                         goto badcode;
 847                 if (icmp6len < sizeof(struct icmp6_router_renum))
 848                         goto badlen;
 849                 break;
 850
 851         default:
 852                 nd6log((LOG_DEBUG,
 853                     "icmp6_input: unknown type %d(src=%s, dst=%s, ifid=%d)\n",
 854                     icmp6->icmp6_type, ip6_sprintf(ip6bufs, &ip6->ip6_src),
 855                     ip6_sprintf(ip6bufd, &ip6->ip6_dst),
 856                     ifp ? ifp->if_index : 0));
 857                 if (icmp6->icmp6_type < ICMP6_ECHO_REQUEST) {
 858                         /* ICMPv6 error: MUST deliver it by spec... */
 859                         code = PRC_NCMDS;
 860                         /* deliver */
 861                 } else {
 862                         /* ICMPv6 informational: MUST not deliver */
 863                         break;
 864                 }
 865         deliver:
 866                 if (icmp6_notify_error(&m, off, icmp6len, code) != 0) {
 867                         /* In this case, m should've been freed. */
 868                         *mp = NULL;
 869                         return (IPPROTO_DONE);
 870                 }
 871                 break;
 872
 873         badcode:
 874                 ICMP6STAT_INC(icp6s_badcode);
 875                 break;
 876
 877         badlen:
 878                 ICMP6STAT_INC(icp6s_badlen);
 879                 break;
 880         }
 881
 882         /* deliver the packet to appropriate sockets */
 883         icmp6_rip6_input(&m, *offp);
 884
 885         *mp = m;
 886         return (IPPROTO_DONE);
 887
 888  freeit:
 889         m_freem(m);
 890         *mp = NULL;
 891         return (IPPROTO_DONE);
 892 }
 893
 894 static int
 895 icmp6_notify_error(struct mbuf **mp, int off, int icmp6len, int code)
 896 {
 897         struct mbuf *m;
 898         struct icmp6_hdr *icmp6;
 899         struct ip6_hdr *eip6;
 900         u_int32_t notifymtu;
 901         struct sockaddr_in6 icmp6src, icmp6dst;
 902
 903         m = *mp;
 904
 905         if (icmp6len < sizeof(struct icmp6_hdr) + sizeof(struct ip6_hdr)) {
 906                 ICMP6STAT_INC(icp6s_tooshort);
 907                 goto freeit;
 908         }
 909
 910         if (m->m_len < off + sizeof(*icmp6) + sizeof(struct ip6_hdr)) {
 911                 m = m_pullup(m, off + sizeof(*icmp6) + sizeof(struct ip6_hdr));
 912                 if (m == NULL) {
 913                         IP6STAT_INC(ip6s_exthdrtoolong);
 914                         *mp = m;
 915                         return (-1);
 916                 }
 917         }
 918         icmp6 = (struct icmp6_hdr *)(mtod(m, caddr_t) + off);
 919         eip6 = (struct ip6_hdr *)(icmp6 + 1);
 920
 921         /* Detect the upper level protocol */
 922         {
 923                 void (*ctlfunc)(int, struct sockaddr *, void *);
 924                 u_int8_t nxt = eip6->ip6_nxt;
 925                 int eoff = off + sizeof(struct icmp6_hdr) +
 926                     sizeof(struct ip6_hdr);
 927                 struct ip6ctlparam ip6cp;
 928                 struct in6_addr *finaldst = NULL;
 929                 int icmp6type = icmp6->icmp6_type;
 930                 struct ip6_frag *fh;
 931                 struct ip6_rthdr *rth;
 932                 struct ip6_rthdr0 *rth0;
 933                 int rthlen;
 934
 935                 while (1) { /* XXX: should avoid infinite loop explicitly? */
 936                         struct ip6_ext *eh;
 937
 938                         switch (nxt) {
 939                         case IPPROTO_HOPOPTS:
 940                         case IPPROTO_DSTOPTS:
 941                         case IPPROTO_AH:
 942                                 if (m->m_len < eoff + sizeof(struct ip6_ext)) {
 943                                         m = m_pullup(m, eoff +
 944                                             sizeof(struct ip6_ext));
 945                                         if (m == NULL) {
 946                                                 IP6STAT_INC(ip6s_exthdrtoolong);
 947                                                 *mp = m;
 948                                                 return (-1);
 949                                         }
 950                                 }
 951                                 eh = (struct ip6_ext *)
 952                                     (mtod(m, caddr_t) + eoff);
 953                                 if (nxt == IPPROTO_AH)
 954                                         eoff += (eh->ip6e_len + 2) << 2;
 955                                 else
 956                                         eoff += (eh->ip6e_len + 1) << 3;
 957                                 nxt = eh->ip6e_nxt;
 958                                 break;
 959                         case IPPROTO_ROUTING:
 960                                 /*
 961                                  * When the erroneous packet contains a
 962                                  * routing header, we should examine the
 963                                  * header to determine the final destination.
 964                                  * Otherwise, we can't properly update
 965                                  * information that depends on the final
 966                                  * destination (e.g. path MTU).
 967                                  */
 968                                 if (m->m_len < eoff + sizeof(*rth)) {
 969                                         m = m_pullup(m, eoff + sizeof(*rth));
 970                                         if (m == NULL) {
 971                                                 IP6STAT_INC(ip6s_exthdrtoolong);
 972                                                 *mp = m;
 973                                                 return (-1);
 974                                         }
 975                                 }
 976                                 rth = (struct ip6_rthdr *)
 977                                     (mtod(m, caddr_t) + eoff);
 978                                 rthlen = (rth->ip6r_len + 1) << 3;
 979                                 /*
 980                                  * XXX: currently there is no
 981                                  * officially defined type other
 982                                  * than type-0.
 983                                  * Note that if the segment left field
 984                                  * is 0, all intermediate hops must
 985                                  * have been passed.
 986                                  */
 987                                 if (rth->ip6r_segleft &&
 988                                     rth->ip6r_type == IPV6_RTHDR_TYPE_0) {
 989                                         int hops;
 990
 991                                         if (m->m_len < eoff + rthlen) {
 992                                                 m = m_pullup(m, eoff + rthlen);
 993                                                 if (m == NULL) {
 994                                                         IP6STAT_INC(
 995                                                             ip6s_exthdrtoolong);
 996                                                         *mp = m;
 997                                                         return (-1);
 998                                                 }
 999                                         }
1000                                         rth0 = (struct ip6_rthdr0 *)
1001                                             (mtod(m, caddr_t) + eoff);
1002                                         /* just ignore a bogus header */
1003                                         if ((rth0->ip6r0_len % 2) == 0 &&
1004                                             (hops = rth0->ip6r0_len/2))
1005                                                 finaldst = (struct in6_addr *)(rth0 + 1) + (hops - 1);
1006                                 }
1007                                 eoff += rthlen;
1008                                 nxt = rth->ip6r_nxt;
1009                                 break;
1010                         case IPPROTO_FRAGMENT:
1011                                 if (m->m_len < eoff + sizeof(struct ip6_frag)) {
1012                                         m = m_pullup(m, eoff +
1013                                             sizeof(struct ip6_frag));
1014                                         if (m == NULL) {
1015                                                 IP6STAT_INC(ip6s_exthdrtoolong);
1016                                                 *mp = m;
1017                                                 return (-1);
1018                                         }
1019                                 }
1020                                 fh = (struct ip6_frag *)(mtod(m, caddr_t) +
1021                                     eoff);
1022                                 /*
1023                                  * Data after a fragment header is meaningless
1024                                  * unless it is the first fragment, but
1025                                  * we'll go to the notify label for path MTU
1026                                  * discovery.
1027                                  */
1028                                 if (fh->ip6f_offlg & IP6F_OFF_MASK)
1029                                         goto notify;
1030
1031                                 eoff += sizeof(struct ip6_frag);
1032                                 nxt = fh->ip6f_nxt;
1033                                 break;
1034                         default:
1035                                 /*
1036                                  * This case includes ESP and the No Next
1037                                  * Header.  In such cases going to the notify
1038                                  * label does not have any meaning
1039                                  * (i.e. ctlfunc will be NULL), but we go
1040                                  * anyway since we might have to update
1041                                  * path MTU information.
1042                                  */
1043                                 goto notify;
1044                         }
1045                 }
1046           notify:
1047                 icmp6 = (struct icmp6_hdr *)(mtod(m, caddr_t) + off);
1048
1049                 /*
1050                  * retrieve parameters from the inner IPv6 header, and convert
1051                  * them into sockaddr structures.
1052                  * XXX: there is no guarantee that the source or destination
1053                  * addresses of the inner packet are in the same scope as
1054                  * the addresses of the icmp packet.  But there is no other
1055                  * way to determine the zone.
1056                  */
1057                 eip6 = (struct ip6_hdr *)(icmp6 + 1);
1058
1059                 bzero(&icmp6dst, sizeof(icmp6dst));
1060                 icmp6dst.sin6_len = sizeof(struct sockaddr_in6);
1061                 icmp6dst.sin6_family = AF_INET6;
1062                 if (finaldst == NULL)
1063                         icmp6dst.sin6_addr = eip6->ip6_dst;
1064                 else
1065                         icmp6dst.sin6_addr = *finaldst;
1066                 if (in6_setscope(&icmp6dst.sin6_addr, m->m_pkthdr.rcvif, NULL))
1067                         goto freeit;
1068                 bzero(&icmp6src, sizeof(icmp6src));
1069                 icmp6src.sin6_len = sizeof(struct sockaddr_in6);
1070                 icmp6src.sin6_family = AF_INET6;
1071                 icmp6src.sin6_addr = eip6->ip6_src;
1072                 if (in6_setscope(&icmp6src.sin6_addr, m->m_pkthdr.rcvif, NULL))
1073                         goto freeit;
1074                 icmp6src.sin6_flowinfo =
1075                     (eip6->ip6_flow & IPV6_FLOWLABEL_MASK);
1076
1077                 if (finaldst == NULL)
1078                         finaldst = &eip6->ip6_dst;
1079                 ip6cp.ip6c_m = m;
1080                 ip6cp.ip6c_icmp6 = icmp6;
1081                 ip6cp.ip6c_ip6 = (struct ip6_hdr *)(icmp6 + 1);
1082                 ip6cp.ip6c_off = eoff;
1083                 ip6cp.ip6c_finaldst = finaldst;
1084                 ip6cp.ip6c_src = &icmp6src;
1085                 ip6cp.ip6c_nxt = nxt;
1086
1087                 if (icmp6type == ICMP6_PACKET_TOO_BIG) {
1088                         notifymtu = ntohl(icmp6->icmp6_mtu);
1089                         ip6cp.ip6c_cmdarg = (void *)&notifymtu;
1090                         icmp6_mtudisc_update(&ip6cp, 1);        /*XXX*/
1091                 }
1092
1093                 ctlfunc = (void (*)(int, struct sockaddr *, void *))
1094                     (inet6sw[ip6_protox[nxt]].pr_ctlinput);
1095                 if (ctlfunc) {
1096                         (void) (*ctlfunc)(code, (struct sockaddr *)&icmp6dst,
1097                             &ip6cp);
1098                 }
1099         }
1100         *mp = m;
1101         return (0);
1102
1103   freeit:
1104         m_freem(m);
1105         *mp = NULL;
1106         return (-1);
1107 }
1108
1109 void
1110 icmp6_mtudisc_update(struct ip6ctlparam *ip6cp, int validated)
1111 {
1112         struct in6_addr *dst = ip6cp->ip6c_finaldst;
1113         struct icmp6_hdr *icmp6 = ip6cp->ip6c_icmp6;
1114         struct mbuf *m = ip6cp->ip6c_m; /* will be necessary for scope issue */
1115         u_int mtu = ntohl(icmp6->icmp6_mtu);
1116         struct in_conninfo inc;
1117
1118 #if 0
1119         /*
1120          * RFC2460 section 5, last paragraph.
1121          * even though minimum link MTU for IPv6 is IPV6_MMTU,
1122          * we may see ICMPv6 too big with mtu < IPV6_MMTU
1123          * due to packet translator in the middle.
1124          * see ip6_output() and ip6_getpmtu() "alwaysfrag" case for
1125          * special handling.
1126          */
1127         if (mtu < IPV6_MMTU)
1128                 return;
1129 #endif
1130
1131         /*
1132          * we reject ICMPv6 too big with abnormally small value.
1133          * XXX what is the good definition of "abnormally small"?
1134          */
1135         if (mtu < sizeof(struct ip6_hdr) + sizeof(struct ip6_frag) + 8)
1136                 return;
1137
1138         if (!validated)
1139                 return;
1140
1141         /*
1142          * In case the suggested mtu is less than IPV6_MMTU, we
1143          * only need to remember that it was for above mentioned
1144          * "alwaysfrag" case.
1145          * Try to be as close to the spec as possible.
1146          */
1147         if (mtu < IPV6_MMTU)
1148                 mtu = IPV6_MMTU - 8;
1149
1150         bzero(&inc, sizeof(inc));
1151         inc.inc_fibnum = M_GETFIB(m);
1152         inc.inc_flags |= INC_ISIPV6;
1153         inc.inc6_faddr = *dst;
1154         if (in6_setscope(&inc.inc6_faddr, m->m_pkthdr.rcvif, NULL))
1155                 return;
1156
1157         if (mtu < tcp_maxmtu6(&inc, NULL)) {
1158                 tcp_hc_updatemtu(&inc, mtu);
1159                 ICMP6STAT_INC(icp6s_pmtuchg);
1160         }
1161 }
1162
1163 /*
1164  * Process a Node Information Query packet, based on
1165  * draft-ietf-ipngwg-icmp-name-lookups-07.
1166  *
1167  * Spec incompatibilities:
1168  * - IPv6 Subject address handling
1169  * - IPv4 Subject address handling support missing
1170  * - Proxy reply (answer even if it's not for me)
1171  * - joins NI group address at in6_ifattach() time only, does not cope
1172  *   with hostname changes by sethostname(3)
1173  */
1174 static struct mbuf *
1175 ni6_input(struct mbuf *m, int off, struct prison *pr)
1176 {
1177         struct icmp6_nodeinfo *ni6, *nni6;
1178         struct mbuf *n = NULL;
1179         u_int16_t qtype;
1180         int subjlen;
1181         int replylen = sizeof(struct ip6_hdr) + sizeof(struct icmp6_nodeinfo);
1182         struct ni_reply_fqdn *fqdn;
1183         int addrs;              /* for NI_QTYPE_NODEADDR */
1184         struct ifnet *ifp = NULL; /* for NI_QTYPE_NODEADDR */
1185         struct in6_addr in6_subj; /* subject address */
1186         struct ip6_hdr *ip6;
1187         int oldfqdn = 0;        /* if 1, return pascal string (03 draft) */
1188         char *subj = NULL;
1189         struct in6_ifaddr *ia6 = NULL;
1190
1191         ip6 = mtod(m, struct ip6_hdr *);
1192         ni6 = (struct icmp6_nodeinfo *)(mtod(m, caddr_t) + off);
1193
1194         /*
1195          * Validate IPv6 source address.
1196          * The default configuration MUST be to refuse answering queries from
1197          * global-scope addresses according to RFC4602.
1198          * Notes:
1199          *  - it's not very clear what "refuse" means; this implementation
1200          *    simply drops it.
1201          *  - it's not very easy to identify global-scope (unicast) addresses
1202          *    since there are many prefixes for them.  It should be safer
1203          *    and in practice sufficient to check "all" but loopback and
1204          *    link-local (note that site-local unicast was deprecated and
1205          *    ULA is defined as global scope-wise)
1206          */
1207         if ((V_icmp6_nodeinfo & ICMP6_NODEINFO_GLOBALOK) == 0 &&
1208             !IN6_IS_ADDR_LOOPBACK(&ip6->ip6_src) &&
1209             !IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_src))
1210                 goto bad;
1211
1212         /*
1213          * Validate IPv6 destination address.
1214          *
1215          * The Responder must discard the Query without further processing
1216          * unless it is one of the Responder's unicast or anycast addresses, or
1217          * a link-local scope multicast address which the Responder has joined.
1218          * [RFC4602, Section 5.]
1219          */
1220         if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
1221                 if (!IN6_IS_ADDR_MC_LINKLOCAL(&ip6->ip6_dst))
1222                         goto bad;
1223                 /* else it's a link-local multicast, fine */
1224         } else {                /* unicast or anycast */
1225                 ia6 = in6ifa_ifwithaddr(&ip6->ip6_dst, 0 /* XXX */);
1226                 if (ia6 == NULL)
1227                         goto bad; /* XXX impossible */
1228
1229                 if ((ia6->ia6_flags & IN6_IFF_TEMPORARY) &&
1230                     !(V_icmp6_nodeinfo & ICMP6_NODEINFO_TMPADDROK)) {
1231                         ifa_free(&ia6->ia_ifa);
1232                         nd6log((LOG_DEBUG, "ni6_input: ignore node info to "
1233                                 "a temporary address in %s:%d",
1234                                __FILE__, __LINE__));
1235                         goto bad;
1236                 }
1237                 ifa_free(&ia6->ia_ifa);
1238         }
1239
1240         /* validate query Subject field. */
1241         qtype = ntohs(ni6->ni_qtype);
1242         subjlen = m->m_pkthdr.len - off - sizeof(struct icmp6_nodeinfo);
1243         switch (qtype) {
1244         case NI_QTYPE_NOOP:
1245         case NI_QTYPE_SUPTYPES:
1246                 /* 07 draft */
1247                 if (ni6->ni_code == ICMP6_NI_SUBJ_FQDN && subjlen == 0)
1248                         break;
1249                 /* FALLTHROUGH */
1250         case NI_QTYPE_FQDN:
1251         case NI_QTYPE_NODEADDR:
1252         case NI_QTYPE_IPV4ADDR:
1253                 switch (ni6->ni_code) {
1254                 case ICMP6_NI_SUBJ_IPV6:
1255 #if ICMP6_NI_SUBJ_IPV6 != 0
1256                 case 0:
1257 #endif
1258                         /*
1259                          * backward compatibility - try to accept 03 draft
1260                          * format, where no Subject is present.
1261                          */
1262                         if (qtype == NI_QTYPE_FQDN && ni6->ni_code == 0 &&
1263                             subjlen == 0) {
1264                                 oldfqdn++;
1265                                 break;
1266                         }
1267 #if ICMP6_NI_SUBJ_IPV6 != 0
1268                         if (ni6->ni_code != ICMP6_NI_SUBJ_IPV6)
1269                                 goto bad;
1270 #endif
1271
1272                         if (subjlen != sizeof(struct in6_addr))
1273                                 goto bad;
1274
1275                         /*
1276                          * Validate Subject address.
1277                          *
1278                          * Not sure what exactly "address belongs to the node"
1279                          * means in the spec, is it just unicast, or what?
1280                          *
1281                          * At this moment we consider Subject address as
1282                          * "belong to the node" if the Subject address equals
1283                          * to the IPv6 destination address; validation for
1284                          * IPv6 destination address should have done enough
1285                          * check for us.
1286                          *
1287                          * We do not do proxy at this moment.
1288                          */
1289                         m_copydata(m, off + sizeof(struct icmp6_nodeinfo),
1290                             subjlen, (caddr_t)&in6_subj);
1291                         if (in6_setscope(&in6_subj, m->m_pkthdr.rcvif, NULL))
1292                                 goto bad;
1293
1294                         subj = (char *)&in6_subj;
1295                         if (IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &in6_subj))
1296                                 break;
1297
1298                         /*
1299                          * XXX if we are to allow other cases, we should really
1300                          * be careful about scope here.
1301                          * basically, we should disallow queries toward IPv6
1302                          * destination X with subject Y,
1303                          * if scope(X) > scope(Y).
1304                          * if we allow scope(X) > scope(Y), it will result in
1305                          * information leakage across scope boundary.
1306                          */
1307                         goto bad;
1308
1309                 case ICMP6_NI_SUBJ_FQDN:
1310                         /*
1311                          * Validate Subject name with gethostname(3).
1312                          *
1313                          * The behavior may need some debate, since:
1314                          * - we are not sure if the node has FQDN as
1315                          *   hostname (returned by gethostname(3)).
1316                          * - the code does wildcard match for truncated names.
1317                          *   however, we are not sure if we want to perform
1318                          *   wildcard match, if gethostname(3) side has
1319                          *   truncated hostname.
1320                          */
1321                         mtx_lock(&pr->pr_mtx);
1322                         n = ni6_nametodns(pr->pr_hostname,
1323                             strlen(pr->pr_hostname), 0);
1324                         mtx_unlock(&pr->pr_mtx);
1325                         if (!n || n->m_next || n->m_len == 0)
1326                                 goto bad;
1327                         if (m->m_len < off + sizeof(struct icmp6_nodeinfo) +
1328                             subjlen) {
1329                                 m = m_pullup(m, off +
1330                                     sizeof(struct icmp6_nodeinfo) + subjlen);
1331                                 if (m == NULL) {
1332                                         IP6STAT_INC(ip6s_exthdrtoolong);
1333                                         goto bad;
1334                                 }
1335                         }
1336                         /* ip6 possibly invalid but not used after. */
1337                         ni6 = (struct icmp6_nodeinfo *)(mtod(m, caddr_t) + off);
1338                         subj = (char *)(mtod(m, caddr_t) + off +
1339                             sizeof(struct icmp6_nodeinfo));
1340                         if (!ni6_dnsmatch(subj, subjlen, mtod(n, const char *),
1341                             n->m_len)) {
1342                                 goto bad;
1343                         }
1344                         m_freem(n);
1345                         n = NULL;
1346                         break;
1347
1348                 case ICMP6_NI_SUBJ_IPV4:        /* XXX: to be implemented? */
1349                 default:
1350                         goto bad;
1351                 }
1352                 break;
1353         }
1354
1355         /* refuse based on configuration.  XXX ICMP6_NI_REFUSED? */
1356         switch (qtype) {
1357         case NI_QTYPE_FQDN:
1358                 if ((V_icmp6_nodeinfo & ICMP6_NODEINFO_FQDNOK) == 0)
1359                         goto bad;
1360                 break;
1361         case NI_QTYPE_NODEADDR:
1362         case NI_QTYPE_IPV4ADDR:
1363                 if ((V_icmp6_nodeinfo & ICMP6_NODEINFO_NODEADDROK) == 0)
1364                         goto bad;
1365                 break;
1366         }
1367
1368         /* guess reply length */
1369         switch (qtype) {
1370         case NI_QTYPE_NOOP:
1371                 break;          /* no reply data */
1372         case NI_QTYPE_SUPTYPES:
1373                 replylen += sizeof(u_int32_t);
1374                 break;
1375         case NI_QTYPE_FQDN:
1376                 /* XXX will append an mbuf */
1377                 replylen += offsetof(struct ni_reply_fqdn, ni_fqdn_namelen);
1378                 break;
1379         case NI_QTYPE_NODEADDR:
1380                 addrs = ni6_addrs(ni6, m, &ifp, (struct in6_addr *)subj);
1381                 if ((replylen += addrs * (sizeof(struct in6_addr) +
1382                     sizeof(u_int32_t))) > MCLBYTES)
1383                         replylen = MCLBYTES; /* XXX: will truncate pkt later */
1384                 break;
1385         case NI_QTYPE_IPV4ADDR:
1386                 /* unsupported - should respond with unknown Qtype? */
1387                 break;
1388         default:
1389                 /*
1390                  * XXX: We must return a reply with the ICMP6 code
1391                  * `unknown Qtype' in this case.  However we regard the case
1392                  * as an FQDN query for backward compatibility.
1393                  * Older versions set a random value to this field,
1394                  * so it rarely varies in the defined qtypes.
1395                  * But the mechanism is not reliable...
1396                  * maybe we should obsolete older versions.
1397                  */
1398                 qtype = NI_QTYPE_FQDN;
1399                 /* XXX will append an mbuf */
1400                 replylen += offsetof(struct ni_reply_fqdn, ni_fqdn_namelen);
1401                 oldfqdn++;
1402                 break;
1403         }
1404
1405         /* Allocate an mbuf to reply. */
1406         if (replylen > MCLBYTES) {
1407                 /*
1408                  * XXX: should we try to allocate more? But MCLBYTES
1409                  * is probably much larger than IPV6_MMTU...
1410                  */
1411                 goto bad;
1412         }
1413         if (replylen > MHLEN)
1414                 n = m_getcl(M_NOWAIT, m->m_type, M_PKTHDR);
1415         else
1416                 n = m_gethdr(M_NOWAIT, m->m_type);
1417         if (n == NULL) {
1418                 m_freem(m);
1419                 return (NULL);
1420         }
1421         m_move_pkthdr(n, m); /* just for recvif and FIB */
1422         n->m_pkthdr.len = n->m_len = replylen;
1423
1424         /* copy mbuf header and IPv6 + Node Information base headers */
1425         bcopy(mtod(m, caddr_t), mtod(n, caddr_t), sizeof(struct ip6_hdr));
1426         nni6 = (struct icmp6_nodeinfo *)(mtod(n, struct ip6_hdr *) + 1);
1427         bcopy((caddr_t)ni6, (caddr_t)nni6, sizeof(struct icmp6_nodeinfo));
1428
1429         /* qtype dependent procedure */
1430         switch (qtype) {
1431         case NI_QTYPE_NOOP:
1432                 nni6->ni_code = ICMP6_NI_SUCCESS;
1433                 nni6->ni_flags = 0;
1434                 break;
1435         case NI_QTYPE_SUPTYPES:
1436         {
1437                 u_int32_t v;
1438                 nni6->ni_code = ICMP6_NI_SUCCESS;
1439                 nni6->ni_flags = htons(0x0000); /* raw bitmap */
1440                 /* supports NOOP, SUPTYPES, FQDN, and NODEADDR */
1441                 v = (u_int32_t)htonl(0x0000000f);
1442                 bcopy(&v, nni6 + 1, sizeof(u_int32_t));
1443                 break;
1444         }
1445         case NI_QTYPE_FQDN:
1446                 nni6->ni_code = ICMP6_NI_SUCCESS;
1447                 fqdn = (struct ni_reply_fqdn *)(mtod(n, caddr_t) +
1448                     sizeof(struct ip6_hdr) + sizeof(struct icmp6_nodeinfo));
1449                 nni6->ni_flags = 0; /* XXX: meaningless TTL */
1450                 fqdn->ni_fqdn_ttl = 0;  /* ditto. */
1451                 /*
1452                  * XXX do we really have FQDN in hostname?
1453                  */
1454                 mtx_lock(&pr->pr_mtx);
1455                 n->m_next = ni6_nametodns(pr->pr_hostname,
1456                     strlen(pr->pr_hostname), oldfqdn);
1457                 mtx_unlock(&pr->pr_mtx);
1458                 if (n->m_next == NULL)
1459                         goto bad;
1460                 /* XXX we assume that n->m_next is not a chain */
1461                 if (n->m_next->m_next != NULL)
1462                         goto bad;
1463                 n->m_pkthdr.len += n->m_next->m_len;
1464                 break;
1465         case NI_QTYPE_NODEADDR:
1466         {
1467                 int lenlim, copied;
1468
1469                 nni6->ni_code = ICMP6_NI_SUCCESS;
1470                 n->m_pkthdr.len = n->m_len =
1471                     sizeof(struct ip6_hdr) + sizeof(struct icmp6_nodeinfo);
1472                 lenlim = M_TRAILINGSPACE(n);
1473                 copied = ni6_store_addrs(ni6, nni6, ifp, lenlim);
1474                 /* XXX: reset mbuf length */
1475                 n->m_pkthdr.len = n->m_len = sizeof(struct ip6_hdr) +
1476                     sizeof(struct icmp6_nodeinfo) + copied;
1477                 break;
1478         }
1479         default:
1480                 break;          /* XXX impossible! */
1481         }
1482
1483         nni6->ni_type = ICMP6_NI_REPLY;
1484         m_freem(m);
1485         return (n);
1486
1487   bad:
1488         m_freem(m);
1489         if (n)
1490                 m_freem(n);
1491         return (NULL);
1492 }
1493
1494 /*
1495  * make a mbuf with DNS-encoded string.  no compression support.
1496  *
1497  * XXX names with less than 2 dots (like "foo" or "foo.section") will be
1498  * treated as truncated name (two \0 at the end).  this is a wild guess.
1499  *
1500  * old - return pascal string if non-zero
1501  */
1502 static struct mbuf *
1503 ni6_nametodns(const char *name, int namelen, int old)
1504 {
1505         struct mbuf *m;
1506         char *cp, *ep;
1507         const char *p, *q;
1508         int i, len, nterm;
1509
1510         if (old)
1511                 len = namelen + 1;
1512         else
1513                 len = MCLBYTES;
1514
1515         /* Because MAXHOSTNAMELEN is usually 256, we use cluster mbuf. */
1516         if (len > MLEN)
1517                 m = m_getcl(M_NOWAIT, MT_DATA, 0);
1518         else
1519                 m = m_get(M_NOWAIT, MT_DATA);
1520         if (m == NULL)
1521                 goto fail;
1522
1523         if (old) {
1524                 m->m_len = len;
1525                 *mtod(m, char *) = namelen;
1526                 bcopy(name, mtod(m, char *) + 1, namelen);
1527                 return m;
1528         } else {
1529                 m->m_len = 0;
1530                 cp = mtod(m, char *);
1531                 ep = mtod(m, char *) + M_TRAILINGSPACE(m);
1532
1533                 /* if not certain about my name, return empty buffer */
1534                 if (namelen == 0)
1535                         return m;
1536
1537                 /*
1538                  * guess if it looks like shortened hostname, or FQDN.
1539                  * shortened hostname needs two trailing "\0".
1540                  */
1541                 i = 0;
1542                 for (p = name; p < name + namelen; p++) {
1543                         if (*p && *p == '.')
1544                                 i++;
1545                 }
1546                 if (i < 2)
1547                         nterm = 2;
1548                 else
1549                         nterm = 1;
1550
1551                 p = name;
1552                 while (cp < ep && p < name + namelen) {
1553                         i = 0;
1554                         for (q = p; q < name + namelen && *q && *q != '.'; q++)
1555                                 i++;
1556                         /* result does not fit into mbuf */
1557                         if (cp + i + 1 >= ep)
1558                                 goto fail;
1559                         /*
1560                          * DNS label length restriction, RFC1035 page 8.
1561                          * "i == 0" case is included here to avoid returning
1562                          * 0-length label on "foo..bar".
1563                          */
1564                         if (i <= 0 || i >= 64)
1565                                 goto fail;
1566                         *cp++ = i;
1567                         bcopy(p, cp, i);
1568                         cp += i;
1569                         p = q;
1570                         if (p < name + namelen && *p == '.')
1571                                 p++;
1572                 }
1573                 /* termination */
1574                 if (cp + nterm >= ep)
1575                         goto fail;
1576                 while (nterm-- > 0)
1577                         *cp++ = '\0';
1578                 m->m_len = cp - mtod(m, char *);
1579                 return m;
1580         }
1581
1582         panic("should not reach here");
1583         /* NOTREACHED */
1584
1585  fail:
1586         if (m)
1587                 m_freem(m);
1588         return NULL;
1589 }
1590
1591 /*
1592  * check if two DNS-encoded string matches.  takes care of truncated
1593  * form (with \0\0 at the end).  no compression support.
1594  * XXX upper/lowercase match (see RFC2065)
1595  */
1596 static int
1597 ni6_dnsmatch(const char *a, int alen, const char *b, int blen)
1598 {
1599         const char *a0, *b0;
1600         int l;
1601
1602         /* simplest case - need validation? */
1603         if (alen == blen && bcmp(a, b, alen) == 0)
1604                 return 1;
1605
1606         a0 = a;
1607         b0 = b;
1608
1609         /* termination is mandatory */
1610         if (alen < 2 || blen < 2)
1611                 return 0;
1612         if (a0[alen - 1] != '\0' || b0[blen - 1] != '\0')
1613                 return 0;
1614         alen--;
1615         blen--;
1616
1617         while (a - a0 < alen && b - b0 < blen) {
1618                 if (a - a0 + 1 > alen || b - b0 + 1 > blen)
1619                         return 0;
1620
1621                 if ((signed char)a[0] < 0 || (signed char)b[0] < 0)
1622                         return 0;
1623                 /* we don't support compression yet */
1624                 if (a[0] >= 64 || b[0] >= 64)
1625                         return 0;
1626
1627                 /* truncated case */
1628                 if (a[0] == 0 && a - a0 == alen - 1)
1629                         return 1;
1630                 if (b[0] == 0 && b - b0 == blen - 1)
1631                         return 1;
1632                 if (a[0] == 0 || b[0] == 0)
1633                         return 0;
1634
1635                 if (a[0] != b[0])
1636                         return 0;
1637                 l = a[0];
1638                 if (a - a0 + 1 + l > alen || b - b0 + 1 + l > blen)
1639                         return 0;
1640                 if (bcmp(a + 1, b + 1, l) != 0)
1641                         return 0;
1642
1643                 a += 1 + l;
1644                 b += 1 + l;
1645         }
1646
1647         if (a - a0 == alen && b - b0 == blen)
1648                 return 1;
1649         else
1650                 return 0;
1651 }
1652
1653 /*
1654  * calculate the number of addresses to be returned in the node info reply.
1655  */
1656 static int
1657 ni6_addrs(struct icmp6_nodeinfo *ni6, struct mbuf *m, struct ifnet **ifpp,
1658     struct in6_addr *subj)
1659 {
1660         struct ifnet *ifp;
1661         struct in6_ifaddr *ifa6;
1662         struct ifaddr *ifa;
1663         int addrs = 0, addrsofif, iffound = 0;
1664         int niflags = ni6->ni_flags;
1665
1666         NET_EPOCH_ASSERT();
1667
1668         if ((niflags & NI_NODEADDR_FLAG_ALL) == 0) {
1669                 switch (ni6->ni_code) {
1670                 case ICMP6_NI_SUBJ_IPV6:
1671                         if (subj == NULL) /* must be impossible... */
1672                                 return (0);
1673                         break;
1674                 default:
1675                         /*
1676                          * XXX: we only support IPv6 subject address for
1677                          * this Qtype.
1678                          */
1679                         return (0);
1680                 }
1681         }
1682
1683         CK_STAILQ_FOREACH(ifp, &V_ifnet, if_link) {
1684                 addrsofif = 0;
1685                 CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
1686                         if (ifa->ifa_addr->sa_family != AF_INET6)
1687                                 continue;
1688                         ifa6 = (struct in6_ifaddr *)ifa;
1689
1690                         if ((niflags & NI_NODEADDR_FLAG_ALL) == 0 &&
1691                             IN6_ARE_ADDR_EQUAL(subj, &ifa6->ia_addr.sin6_addr))
1692                                 iffound = 1;
1693
1694                         /*
1695                          * IPv4-mapped addresses can only be returned by a
1696                          * Node Information proxy, since they represent
1697                          * addresses of IPv4-only nodes, which perforce do
1698                          * not implement this protocol.
1699                          * [icmp-name-lookups-07, Section 5.4]
1700                          * So we don't support NI_NODEADDR_FLAG_COMPAT in
1701                          * this function at this moment.
1702                          */
1703
1704                         /* What do we have to do about ::1? */
1705                         switch (in6_addrscope(&ifa6->ia_addr.sin6_addr)) {
1706                         case IPV6_ADDR_SCOPE_LINKLOCAL:
1707                                 if ((niflags & NI_NODEADDR_FLAG_LINKLOCAL) == 0)
1708                                         continue;
1709                                 break;
1710                         case IPV6_ADDR_SCOPE_SITELOCAL:
1711                                 if ((niflags & NI_NODEADDR_FLAG_SITELOCAL) == 0)
1712                                         continue;
1713                                 break;
1714                         case IPV6_ADDR_SCOPE_GLOBAL:
1715                                 if ((niflags & NI_NODEADDR_FLAG_GLOBAL) == 0)
1716                                         continue;
1717                                 break;
1718                         default:
1719                                 continue;
1720                         }
1721
1722                         /*
1723                          * check if anycast is okay.
1724                          * XXX: just experimental.  not in the spec.
1725                          */
1726                         if ((ifa6->ia6_flags & IN6_IFF_ANYCAST) != 0 &&
1727                             (niflags & NI_NODEADDR_FLAG_ANYCAST) == 0)
1728                                 continue; /* we need only unicast addresses */
1729                         if ((ifa6->ia6_flags & IN6_IFF_TEMPORARY) != 0 &&
1730                             (V_icmp6_nodeinfo & ICMP6_NODEINFO_TMPADDROK) == 0) {
1731                                 continue;
1732                         }
1733                         addrsofif++; /* count the address */
1734                 }
1735                 if (iffound) {
1736                         *ifpp = ifp;
1737                         return (addrsofif);
1738                 }
1739
1740                 addrs += addrsofif;
1741         }
1742
1743         return (addrs);
1744 }
1745
1746 static int
1747 ni6_store_addrs(struct icmp6_nodeinfo *ni6, struct icmp6_nodeinfo *nni6,
1748     struct ifnet *ifp0, int resid)
1749 {
1750         struct ifnet *ifp;
1751         struct in6_ifaddr *ifa6;
1752         struct ifaddr *ifa;
1753         struct ifnet *ifp_dep = NULL;
1754         int copied = 0, allow_deprecated = 0;
1755         u_char *cp = (u_char *)(nni6 + 1);
1756         int niflags = ni6->ni_flags;
1757         u_int32_t ltime;
1758
1759         NET_EPOCH_ASSERT();
1760
1761         if (ifp0 == NULL && !(niflags & NI_NODEADDR_FLAG_ALL))
1762                 return (0);     /* needless to copy */
1763
1764         ifp = ifp0 ? ifp0 : CK_STAILQ_FIRST(&V_ifnet);
1765   again:
1766
1767         for (; ifp; ifp = CK_STAILQ_NEXT(ifp, if_link)) {
1768                 CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
1769                         if (ifa->ifa_addr->sa_family != AF_INET6)
1770                                 continue;
1771                         ifa6 = (struct in6_ifaddr *)ifa;
1772
1773                         if ((ifa6->ia6_flags & IN6_IFF_DEPRECATED) != 0 &&
1774                             allow_deprecated == 0) {
1775                                 /*
1776                                  * prefererred address should be put before
1777                                  * deprecated addresses.
1778                                  */
1779
1780                                 /* record the interface for later search */
1781                                 if (ifp_dep == NULL)
1782                                         ifp_dep = ifp;
1783
1784                                 continue;
1785                         } else if ((ifa6->ia6_flags & IN6_IFF_DEPRECATED) == 0 &&
1786                             allow_deprecated != 0)
1787                                 continue; /* we now collect deprecated addrs */
1788
1789                         /* What do we have to do about ::1? */
1790                         switch (in6_addrscope(&ifa6->ia_addr.sin6_addr)) {
1791                         case IPV6_ADDR_SCOPE_LINKLOCAL:
1792                                 if ((niflags & NI_NODEADDR_FLAG_LINKLOCAL) == 0)
1793                                         continue;
1794                                 break;
1795                         case IPV6_ADDR_SCOPE_SITELOCAL:
1796                                 if ((niflags & NI_NODEADDR_FLAG_SITELOCAL) == 0)
1797                                         continue;
1798                                 break;
1799                         case IPV6_ADDR_SCOPE_GLOBAL:
1800                                 if ((niflags & NI_NODEADDR_FLAG_GLOBAL) == 0)
1801                                         continue;
1802                                 break;
1803                         default:
1804                                 continue;
1805                         }
1806
1807                         /*
1808                          * check if anycast is okay.
1809                          * XXX: just experimental.  not in the spec.
1810                          */
1811                         if ((ifa6->ia6_flags & IN6_IFF_ANYCAST) != 0 &&
1812                             (niflags & NI_NODEADDR_FLAG_ANYCAST) == 0)
1813                                 continue;
1814                         if ((ifa6->ia6_flags & IN6_IFF_TEMPORARY) != 0 &&
1815                             (V_icmp6_nodeinfo & ICMP6_NODEINFO_TMPADDROK) == 0) {
1816                                 continue;
1817                         }
1818
1819                         /* now we can copy the address */
1820                         if (resid < sizeof(struct in6_addr) +
1821                             sizeof(u_int32_t)) {
1822                                 /*
1823                                  * We give up much more copy.
1824                                  * Set the truncate flag and return.
1825                                  */
1826                                 nni6->ni_flags |= NI_NODEADDR_FLAG_TRUNCATE;
1827                                 return (copied);
1828                         }
1829
1830                         /*
1831                          * Set the TTL of the address.
1832                          * The TTL value should be one of the following
1833                          * according to the specification:
1834                          *
1835                          * 1. The remaining lifetime of a DHCP lease on the
1836                          *    address, or
1837                          * 2. The remaining Valid Lifetime of a prefix from
1838                          *    which the address was derived through Stateless
1839                          *    Autoconfiguration.
1840                          *
1841                          * Note that we currently do not support stateful
1842                          * address configuration by DHCPv6, so the former
1843                          * case can't happen.
1844                          */
1845                         if (ifa6->ia6_lifetime.ia6t_expire == 0)
1846                                 ltime = ND6_INFINITE_LIFETIME;
1847                         else {
1848                                 if (ifa6->ia6_lifetime.ia6t_expire >
1849                                     time_uptime)
1850                                         ltime = htonl(ifa6->ia6_lifetime.ia6t_expire - time_uptime);
1851                                 else
1852                                         ltime = 0;
1853                         }
1854
1855                         bcopy(&ltime, cp, sizeof(u_int32_t));
1856                         cp += sizeof(u_int32_t);
1857
1858                         /* copy the address itself */
1859                         bcopy(&ifa6->ia_addr.sin6_addr, cp,
1860                             sizeof(struct in6_addr));
1861                         in6_clearscope((struct in6_addr *)cp); /* XXX */
1862                         cp += sizeof(struct in6_addr);
1863
1864                         resid -= (sizeof(struct in6_addr) + sizeof(u_int32_t));
1865                         copied += (sizeof(struct in6_addr) + sizeof(u_int32_t));
1866                 }
1867                 if (ifp0)       /* we need search only on the specified IF */
1868                         break;
1869         }
1870
1871         if (allow_deprecated == 0 && ifp_dep != NULL) {
1872                 ifp = ifp_dep;
1873                 allow_deprecated = 1;
1874
1875                 goto again;
1876         }
1877
1878         return (copied);
1879 }
1880
1881 /*
1882  * XXX almost dup'ed code with rip6_input.
1883  */
1884 static int
1885 icmp6_rip6_input(struct mbuf **mp, int off)
1886 {
1887         struct mbuf *m = *mp;
1888         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
1889         struct inpcb *inp;
1890         struct inpcb *last = NULL;
1891         struct sockaddr_in6 fromsa;
1892         struct icmp6_hdr *icmp6;
1893         struct mbuf *opts = NULL;
1894
1895         NET_EPOCH_ASSERT();
1896
1897         /* This is assumed to be safe; icmp6_input() does a pullup. */
1898         icmp6 = (struct icmp6_hdr *)((caddr_t)ip6 + off);
1899
1900         /*
1901          * XXX: the address may have embedded scope zone ID, which should be
1902          * hidden from applications.
1903          */
1904         bzero(&fromsa, sizeof(fromsa));
1905         fromsa.sin6_family = AF_INET6;
1906         fromsa.sin6_len = sizeof(struct sockaddr_in6);
1907         fromsa.sin6_addr = ip6->ip6_src;
1908         if (sa6_recoverscope(&fromsa)) {
1909                 m_freem(m);
1910                 *mp = NULL;
1911                 return (IPPROTO_DONE);
1912         }
1913
1914         CK_LIST_FOREACH(inp, &V_ripcb, inp_list) {
1915                 if ((inp->inp_vflag & INP_IPV6) == 0)
1916                         continue;
1917                 if (inp->inp_ip_p != IPPROTO_ICMPV6)
1918                         continue;
1919                 if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr) &&
1920                    !IN6_ARE_ADDR_EQUAL(&inp->in6p_laddr, &ip6->ip6_dst))
1921                         continue;
1922                 if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr) &&
1923                    !IN6_ARE_ADDR_EQUAL(&inp->in6p_faddr, &ip6->ip6_src))
1924                         continue;
1925                 INP_RLOCK(inp);
1926                 if (__predict_false(inp->inp_flags2 & INP_FREED)) {
1927                         INP_RUNLOCK(inp);
1928                         continue;
1929                 }
1930                 if (ICMP6_FILTER_WILLBLOCK(icmp6->icmp6_type,
1931                     inp->in6p_icmp6filt)) {
1932                         INP_RUNLOCK(inp);
1933                         continue;
1934                 }
1935                 if (last != NULL) {
1936                         struct  mbuf *n = NULL;
1937
1938                         /*
1939                          * Recent network drivers tend to allocate a single
1940                          * mbuf cluster, rather than to make a couple of
1941                          * mbufs without clusters.  Also, since the IPv6 code
1942                          * path tries to avoid m_pullup(), it is highly
1943                          * probable that we still have an mbuf cluster here
1944                          * even though the necessary length can be stored in an
1945                          * mbuf's internal buffer.
1946                          * Meanwhile, the default size of the receive socket
1947                          * buffer for raw sockets is not so large.  This means
1948                          * the possibility of packet loss is relatively higher
1949                          * than before.  To avoid this scenario, we copy the
1950                          * received data to a separate mbuf that does not use
1951                          * a cluster, if possible.
1952                          * XXX: it is better to copy the data after stripping
1953                          * intermediate headers.
1954                          */
1955                         if ((m->m_flags & M_EXT) && m->m_next == NULL &&
1956                             m->m_len <= MHLEN) {
1957                                 n = m_get(M_NOWAIT, m->m_type);
1958                                 if (n != NULL) {
1959                                         if (m_dup_pkthdr(n, m, M_NOWAIT)) {
1960                                                 bcopy(m->m_data, n->m_data,
1961                                                       m->m_len);
1962                                                 n->m_len = m->m_len;
1963                                         } else {
1964                                                 m_free(n);
1965                                                 n = NULL;
1966                                         }
1967                                 }
1968                         }
1969                         if (n != NULL ||
1970                             (n = m_copym(m, 0, M_COPYALL, M_NOWAIT)) != NULL) {
1971                                 if (last->inp_flags & INP_CONTROLOPTS)
1972                                         ip6_savecontrol(last, n, &opts);
1973                                 /* strip intermediate headers */
1974                                 m_adj(n, off);
1975                                 SOCKBUF_LOCK(&last->inp_socket->so_rcv);
1976                                 if (sbappendaddr_locked(
1977                                     &last->inp_socket->so_rcv,
1978                                     (struct sockaddr *)&fromsa, n, opts)
1979                                     == 0) {
1980                                         /* should notify about lost packet */
1981                                         m_freem(n);
1982                                         if (opts) {
1983                                                 m_freem(opts);
1984                                         }
1985                                         SOCKBUF_UNLOCK(
1986                                             &last->inp_socket->so_rcv);
1987                                 } else
1988                                         sorwakeup_locked(last->inp_socket);
1989                                 opts = NULL;
1990                         }
1991                         INP_RUNLOCK(last);
1992                 }
1993                 last = inp;
1994         }
1995         if (last != NULL) {
1996                 if (last->inp_flags & INP_CONTROLOPTS)
1997                         ip6_savecontrol(last, m, &opts);
1998                 /* strip intermediate headers */
1999                 m_adj(m, off);
2000
2001                 /* avoid using mbuf clusters if possible (see above) */
2002                 if ((m->m_flags & M_EXT) && m->m_next == NULL &&
2003                     m->m_len <= MHLEN) {
2004                         struct mbuf *n;
2005
2006                         n = m_get(M_NOWAIT, m->m_type);
2007                         if (n != NULL) {
2008                                 if (m_dup_pkthdr(n, m, M_NOWAIT)) {
2009                                         bcopy(m->m_data, n->m_data, m->m_len);
2010                                         n->m_len = m->m_len;
2011
2012                                         m_freem(m);
2013                                         m = n;
2014                                 } else {
2015                                         m_freem(n);
2016                                         n = NULL;
2017                                 }
2018                         }
2019                 }
2020                 SOCKBUF_LOCK(&last->inp_socket->so_rcv);
2021                 if (sbappendaddr_locked(&last->inp_socket->so_rcv,
2022                     (struct sockaddr *)&fromsa, m, opts) == 0) {
2023                         m_freem(m);
2024                         if (opts)
2025                                 m_freem(opts);
2026                         SOCKBUF_UNLOCK(&last->inp_socket->so_rcv);
2027                 } else
2028                         sorwakeup_locked(last->inp_socket);
2029                 INP_RUNLOCK(last);
2030         } else {
2031                 m_freem(m);
2032                 IP6STAT_DEC(ip6s_delivered);
2033         }
2034         *mp = NULL;
2035         return (IPPROTO_DONE);
2036 }
2037
2038 /*
2039  * Reflect the ip6 packet back to the source.
2040  * OFF points to the icmp6 header, counted from the top of the mbuf.
2041  */
2042 static void
2043 icmp6_reflect(struct mbuf *m, size_t off)
2044 {
2045         struct in6_addr src6, *srcp;
2046         struct ip6_hdr *ip6;
2047         struct icmp6_hdr *icmp6;
2048         struct in6_ifaddr *ia = NULL;
2049         struct ifnet *outif = NULL;
2050         int plen;
2051         int type, code, hlim;
2052
2053         /* too short to reflect */
2054         if (off < sizeof(struct ip6_hdr)) {
2055                 nd6log((LOG_DEBUG,
2056                     "sanity fail: off=%lx, sizeof(ip6)=%lx in %s:%d\n",
2057                     (u_long)off, (u_long)sizeof(struct ip6_hdr),
2058                     __FILE__, __LINE__));
2059                 goto bad;
2060         }
2061
2062         /*
2063          * If there are extra headers between IPv6 and ICMPv6, strip
2064          * off that header first.
2065          */
2066 #ifdef DIAGNOSTIC
2067         if (sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr) > MHLEN)
2068                 panic("assumption failed in icmp6_reflect");
2069 #endif
2070         if (off > sizeof(struct ip6_hdr)) {
2071                 size_t l;
2072                 struct ip6_hdr nip6;
2073
2074                 l = off - sizeof(struct ip6_hdr);
2075                 m_copydata(m, 0, sizeof(nip6), (caddr_t)&nip6);
2076                 m_adj(m, l);
2077                 l = sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr);
2078                 if (m->m_len < l) {
2079                         if ((m = m_pullup(m, l)) == NULL)
2080                                 return;
2081                 }
2082                 bcopy((caddr_t)&nip6, mtod(m, caddr_t), sizeof(nip6));
2083         } else /* off == sizeof(struct ip6_hdr) */ {
2084                 size_t l;
2085                 l = sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr);
2086                 if (m->m_len < l) {
2087                         if ((m = m_pullup(m, l)) == NULL)
2088                                 return;
2089                 }
2090         }
2091         plen = m->m_pkthdr.len - sizeof(struct ip6_hdr);
2092         ip6 = mtod(m, struct ip6_hdr *);
2093         ip6->ip6_nxt = IPPROTO_ICMPV6;
2094         icmp6 = (struct icmp6_hdr *)(ip6 + 1);
2095         type = icmp6->icmp6_type; /* keep type for statistics */
2096         code = icmp6->icmp6_code; /* ditto. */
2097         hlim = 0;
2098         srcp = NULL;
2099
2100         /*
2101          * If the incoming packet was addressed directly to us (i.e. unicast),
2102          * use dst as the src for the reply.
2103          * The IN6_IFF_NOTREADY case should be VERY rare, but is possible
2104          * (for example) when we encounter an error while forwarding procedure
2105          * destined to a duplicated address of ours.
2106          */
2107         if (!IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
2108                 ia = in6ifa_ifwithaddr(&ip6->ip6_dst, 0 /* XXX */);
2109                 if (ia != NULL && !(ia->ia6_flags &
2110                     (IN6_IFF_ANYCAST|IN6_IFF_NOTREADY))) {
2111                         src6 = ia->ia_addr.sin6_addr;
2112                         srcp = &src6;
2113
2114                         if (m->m_pkthdr.rcvif != NULL) {
2115                                 /* XXX: This may not be the outgoing interface */
2116                                 hlim = ND_IFINFO(m->m_pkthdr.rcvif)->chlim;
2117                         } else
2118                                 hlim = V_ip6_defhlim;
2119                 }
2120                 if (ia != NULL)
2121                         ifa_free(&ia->ia_ifa);
2122         }
2123
2124         if (srcp == NULL) {
2125                 int error;
2126                 struct in6_addr dst6;
2127                 uint32_t scopeid;
2128
2129                 /*
2130                  * This case matches to multicasts, our anycast, or unicasts
2131                  * that we do not own.  Select a source address based on the
2132                  * source address of the erroneous packet.
2133                  */
2134                 in6_splitscope(&ip6->ip6_src, &dst6, &scopeid);
2135                 error = in6_selectsrc_addr(M_GETFIB(m), &dst6,
2136                     scopeid, NULL, &src6, &hlim);
2137
2138                 if (error) {
2139                         char ip6buf[INET6_ADDRSTRLEN];
2140                         nd6log((LOG_DEBUG,
2141                             "icmp6_reflect: source can't be determined: "
2142                             "dst=%s, error=%d\n",
2143                             ip6_sprintf(ip6buf, &ip6->ip6_dst), error));
2144                         goto bad;
2145                 }
2146                 srcp = &src6;
2147         }
2148         /*
2149          * ip6_input() drops a packet if its src is multicast.
2150          * So, the src is never multicast.
2151          */
2152         ip6->ip6_dst = ip6->ip6_src;
2153         ip6->ip6_src = *srcp;
2154         ip6->ip6_flow = 0;
2155         ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
2156         ip6->ip6_vfc |= IPV6_VERSION;
2157         ip6->ip6_nxt = IPPROTO_ICMPV6;
2158         ip6->ip6_hlim = hlim;
2159
2160         icmp6->icmp6_cksum = 0;
2161         icmp6->icmp6_cksum = in6_cksum(m, IPPROTO_ICMPV6,
2162             sizeof(struct ip6_hdr), plen);
2163
2164         /*
2165          * XXX option handling
2166          */
2167
2168         m->m_flags &= ~(M_BCAST|M_MCAST);
2169         m->m_pkthdr.rcvif = NULL;
2170         ip6_output(m, NULL, NULL, 0, NULL, &outif, NULL);
2171         if (outif)
2172                 icmp6_ifoutstat_inc(outif, type, code);
2173
2174         return;
2175
2176  bad:
2177         m_freem(m);
2178         return;
2179 }
2180
2181 void
2182 icmp6_fasttimo(void)
2183 {
2184
2185         mld_fasttimo();
2186 }
2187
2188 void
2189 icmp6_slowtimo(void)
2190 {
2191
2192         mld_slowtimo();
2193 }
2194
2195 static const char *
2196 icmp6_redirect_diag(struct in6_addr *src6, struct in6_addr *dst6,
2197     struct in6_addr *tgt6)
2198 {
2199         static char buf[1024];
2200         char ip6bufs[INET6_ADDRSTRLEN];
2201         char ip6bufd[INET6_ADDRSTRLEN];
2202         char ip6buft[INET6_ADDRSTRLEN];
2203         snprintf(buf, sizeof(buf), "(src=%s dst=%s tgt=%s)",
2204             ip6_sprintf(ip6bufs, src6), ip6_sprintf(ip6bufd, dst6),
2205             ip6_sprintf(ip6buft, tgt6));
2206         return buf;
2207 }
2208
2209 void
2210 icmp6_redirect_input(struct mbuf *m, int off)
2211 {
2212         struct ifnet *ifp;
2213         struct ip6_hdr *ip6;
2214         struct nd_redirect *nd_rd;
2215         struct in6_addr src6, redtgt6, reddst6;
2216         union nd_opts ndopts;
2217         char ip6buf[INET6_ADDRSTRLEN];
2218         char *lladdr;
2219         int icmp6len, is_onlink, is_router, lladdrlen;
2220
2221         M_ASSERTPKTHDR(m);
2222         KASSERT(m->m_pkthdr.rcvif != NULL, ("%s: no rcvif", __func__));
2223
2224         /* XXX if we are router, we don't update route by icmp6 redirect */
2225         if (V_ip6_forwarding)
2226                 goto freeit;
2227         if (!V_icmp6_rediraccept)
2228                 goto freeit;
2229
2230         /* RFC 6980: Nodes MUST silently ignore fragments */
2231         if(m->m_flags & M_FRAGMENTED)
2232                 goto freeit;
2233
2234         ip6 = mtod(m, struct ip6_hdr *);
2235         icmp6len = ntohs(ip6->ip6_plen);
2236         if (m->m_len < off + icmp6len) {
2237                 m = m_pullup(m, off + icmp6len);
2238                 if (m == NULL) {
2239                         IP6STAT_INC(ip6s_exthdrtoolong);
2240                         return;
2241                 }
2242         }
2243         ip6 = mtod(m, struct ip6_hdr *);
2244         nd_rd = (struct nd_redirect *)((caddr_t)ip6 + off);
2245
2246         ifp = m->m_pkthdr.rcvif;
2247         redtgt6 = nd_rd->nd_rd_target;
2248         reddst6 = nd_rd->nd_rd_dst;
2249
2250         if (in6_setscope(&redtgt6, ifp, NULL) ||
2251             in6_setscope(&reddst6, ifp, NULL)) {
2252                 goto freeit;
2253         }
2254
2255         /* validation */
2256         src6 = ip6->ip6_src;
2257         if (!IN6_IS_ADDR_LINKLOCAL(&src6)) {
2258                 nd6log((LOG_ERR,
2259                     "ICMP6 redirect sent from %s rejected; "
2260                     "must be from linklocal\n",
2261                     ip6_sprintf(ip6buf, &src6)));
2262                 goto bad;
2263         }
2264         if (ip6->ip6_hlim != 255) {
2265                 nd6log((LOG_ERR,
2266                     "ICMP6 redirect sent from %s rejected; "
2267                     "hlim=%d (must be 255)\n",
2268                     ip6_sprintf(ip6buf, &src6), ip6->ip6_hlim));
2269                 goto bad;
2270         }
2271     {
2272         /* ip6->ip6_src must be equal to gw for icmp6->icmp6_reddst */
2273         struct nhop_object *nh;
2274         struct in6_addr kdst;
2275         uint32_t scopeid;
2276
2277         in6_splitscope(&reddst6, &kdst, &scopeid);
2278         NET_EPOCH_ASSERT();
2279         nh = fib6_lookup(ifp->if_fib, &kdst, scopeid, 0, 0);
2280         if (nh == NULL) {
2281                 struct in6_addr nh_addr;
2282                 nh_addr = ifatoia6(nh->nh_ifa)->ia_addr.sin6_addr;
2283                 if ((nh->nh_flags & NHF_GATEWAY) == 0) {
2284                         nd6log((LOG_ERR,
2285                             "ICMP6 redirect rejected; no route "
2286                             "with inet6 gateway found for redirect dst: %s\n",
2287                             icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2288                         goto bad;
2289                 }
2290
2291                 /*
2292                  * Embed scope zone id into next hop address.
2293                  */
2294                 nh_addr = nh->gw6_sa.sin6_addr;
2295
2296                 if (IN6_ARE_ADDR_EQUAL(&src6, &nh_addr) == 0) {
2297                         nd6log((LOG_ERR,
2298                             "ICMP6 redirect rejected; "
2299                             "not equal to gw-for-src=%s (must be same): "
2300                             "%s\n",
2301                             ip6_sprintf(ip6buf, &nh_addr),
2302                             icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2303                         goto bad;
2304                 }
2305         } else {
2306                 nd6log((LOG_ERR,
2307                     "ICMP6 redirect rejected; "
2308                     "no route found for redirect dst: %s\n",
2309                     icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2310                 goto bad;
2311         }
2312     }
2313         if (IN6_IS_ADDR_MULTICAST(&reddst6)) {
2314                 nd6log((LOG_ERR,
2315                     "ICMP6 redirect rejected; "
2316                     "redirect dst must be unicast: %s\n",
2317                     icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2318                 goto bad;
2319         }
2320
2321         is_router = is_onlink = 0;
2322         if (IN6_IS_ADDR_LINKLOCAL(&redtgt6))
2323                 is_router = 1;  /* router case */
2324         if (bcmp(&redtgt6, &reddst6, sizeof(redtgt6)) == 0)
2325                 is_onlink = 1;  /* on-link destination case */
2326         if (!is_router && !is_onlink) {
2327                 nd6log((LOG_ERR,
2328                     "ICMP6 redirect rejected; "
2329                     "neither router case nor onlink case: %s\n",
2330                     icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2331                 goto bad;
2332         }
2333
2334         icmp6len -= sizeof(*nd_rd);
2335         nd6_option_init(nd_rd + 1, icmp6len, &ndopts);
2336         if (nd6_options(&ndopts) < 0) {
2337                 nd6log((LOG_INFO, "%s: invalid ND option, rejected: %s\n",
2338                     __func__, icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2339                 /* nd6_options have incremented stats */
2340                 goto freeit;
2341         }
2342
2343         lladdr = NULL;
2344         lladdrlen = 0;
2345         if (ndopts.nd_opts_tgt_lladdr) {
2346                 lladdr = (char *)(ndopts.nd_opts_tgt_lladdr + 1);
2347                 lladdrlen = ndopts.nd_opts_tgt_lladdr->nd_opt_len << 3;
2348         }
2349
2350         if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
2351                 nd6log((LOG_INFO, "%s: lladdrlen mismatch for %s "
2352                     "(if %d, icmp6 packet %d): %s\n",
2353                     __func__, ip6_sprintf(ip6buf, &redtgt6),
2354                     ifp->if_addrlen, lladdrlen - 2,
2355                     icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2356                 goto bad;
2357         }
2358
2359         /* Validation passed. */
2360
2361         /* RFC 2461 8.3 */
2362         nd6_cache_lladdr(ifp, &redtgt6, lladdr, lladdrlen, ND_REDIRECT,
2363             is_onlink ? ND_REDIRECT_ONLINK : ND_REDIRECT_ROUTER);
2364
2365         /*
2366          * Install a gateway route in the better-router case or an interface
2367          * route in the on-link-destination case.
2368          */
2369         {
2370                 struct sockaddr_in6 sdst;
2371                 struct sockaddr_in6 sgw;
2372                 struct sockaddr_in6 ssrc;
2373                 struct sockaddr *gw;
2374                 int rt_flags;
2375                 u_int fibnum;
2376
2377                 bzero(&sdst, sizeof(sdst));
2378                 bzero(&ssrc, sizeof(ssrc));
2379                 sdst.sin6_family = ssrc.sin6_family = AF_INET6;
2380                 sdst.sin6_len = ssrc.sin6_len = sizeof(struct sockaddr_in6);
2381                 bcopy(&reddst6, &sdst.sin6_addr, sizeof(struct in6_addr));
2382                 bcopy(&src6, &ssrc.sin6_addr, sizeof(struct in6_addr));
2383                 rt_flags = 0;
2384                 if (is_router) {
2385                         bzero(&sgw, sizeof(sgw));
2386                         sgw.sin6_family = AF_INET6;
2387                         sgw.sin6_len = sizeof(struct sockaddr_in6);
2388                         bcopy(&redtgt6, &sgw.sin6_addr,
2389                                 sizeof(struct in6_addr));
2390                         gw = (struct sockaddr *)&sgw;
2391                         rt_flags |= RTF_GATEWAY;
2392                 } else
2393                         gw = ifp->if_addr->ifa_addr;
2394                 for (fibnum = 0; fibnum < rt_numfibs; fibnum++)
2395                         rib_add_redirect(fibnum, (struct sockaddr *)&sdst, gw,
2396                             (struct sockaddr *)&ssrc, ifp, rt_flags,
2397                             V_icmp6_redirtimeout);
2398         }
2399         /* finally update cached route in each socket via pfctlinput */
2400     {
2401         struct sockaddr_in6 sdst;
2402
2403         bzero(&sdst, sizeof(sdst));
2404         sdst.sin6_family = AF_INET6;
2405         sdst.sin6_len = sizeof(struct sockaddr_in6);
2406         bcopy(&reddst6, &sdst.sin6_addr, sizeof(struct in6_addr));
2407         pfctlinput(PRC_REDIRECT_HOST, (struct sockaddr *)&sdst);
2408     }
2409
2410  freeit:
2411         m_freem(m);
2412         return;
2413
2414  bad:
2415         ICMP6STAT_INC(icp6s_badredirect);
2416         m_freem(m);
2417 }
2418
2419 void
2420 icmp6_redirect_output(struct mbuf *m0, struct nhop_object *nh)
2421 {
2422         struct ifnet *ifp;      /* my outgoing interface */
2423         struct in6_addr *ifp_ll6;
2424         struct in6_addr *router_ll6;
2425         struct ip6_hdr *sip6;   /* m0 as struct ip6_hdr */
2426         struct mbuf *m = NULL;  /* newly allocated one */
2427         struct m_tag *mtag;
2428         struct ip6_hdr *ip6;    /* m as struct ip6_hdr */
2429         struct nd_redirect *nd_rd;
2430         struct llentry *ln = NULL;
2431         size_t maxlen;
2432         u_char *p;
2433         struct ifnet *outif = NULL;
2434         struct sockaddr_in6 src_sa;
2435
2436         icmp6_errcount(ND_REDIRECT, 0);
2437
2438         /* if we are not router, we don't send icmp6 redirect */
2439         if (!V_ip6_forwarding)
2440                 goto fail;
2441
2442         /* sanity check */
2443         if (!m0 || !nh || !(NH_IS_VALID(nh)) || !(ifp = nh->nh_ifp))
2444                 goto fail;
2445
2446         /*
2447          * Address check:
2448          *  the source address must identify a neighbor, and
2449          *  the destination address must not be a multicast address
2450          *  [RFC 2461, sec 8.2]
2451          */
2452         sip6 = mtod(m0, struct ip6_hdr *);
2453         bzero(&src_sa, sizeof(src_sa));
2454         src_sa.sin6_family = AF_INET6;
2455         src_sa.sin6_len = sizeof(src_sa);
2456         src_sa.sin6_addr = sip6->ip6_src;
2457         if (nd6_is_addr_neighbor(&src_sa, ifp) == 0)
2458                 goto fail;
2459         if (IN6_IS_ADDR_MULTICAST(&sip6->ip6_dst))
2460                 goto fail;      /* what should we do here? */
2461
2462         /* rate limit */
2463         if (icmp6_ratelimit(&sip6->ip6_src, ND_REDIRECT, 0))
2464                 goto fail;
2465
2466         /*
2467          * Since we are going to append up to 1280 bytes (= IPV6_MMTU),
2468          * we almost always ask for an mbuf cluster for simplicity.
2469          * (MHLEN < IPV6_MMTU is almost always true)
2470          */
2471 #if IPV6_MMTU >= MCLBYTES
2472 # error assumption failed about IPV6_MMTU and MCLBYTES
2473 #endif
2474         m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
2475         if (m == NULL)
2476                 goto fail;
2477         M_SETFIB(m, M_GETFIB(m0));
2478         maxlen = M_TRAILINGSPACE(m);
2479         maxlen = min(IPV6_MMTU, maxlen);
2480         /* just for safety */
2481         if (maxlen < sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr) +
2482             ((sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7)) {
2483                 goto fail;
2484         }
2485
2486         {
2487                 /* get ip6 linklocal address for ifp(my outgoing interface). */
2488                 struct in6_ifaddr *ia;
2489                 if ((ia = in6ifa_ifpforlinklocal(ifp,
2490                                                  IN6_IFF_NOTREADY|
2491                                                  IN6_IFF_ANYCAST)) == NULL)
2492                         goto fail;
2493                 ifp_ll6 = &ia->ia_addr.sin6_addr;
2494                 /* XXXRW: reference released prematurely. */
2495                 ifa_free(&ia->ia_ifa);
2496         }
2497
2498         /* get ip6 linklocal address for the router. */
2499         if (nh->nh_flags & NHF_GATEWAY) {
2500                 struct sockaddr_in6 *sin6;
2501                 sin6 = &nh->gw6_sa;
2502                 router_ll6 = &sin6->sin6_addr;
2503                 if (!IN6_IS_ADDR_LINKLOCAL(router_ll6))
2504                         router_ll6 = (struct in6_addr *)NULL;
2505         } else
2506                 router_ll6 = (struct in6_addr *)NULL;
2507
2508         /* ip6 */
2509         ip6 = mtod(m, struct ip6_hdr *);
2510         ip6->ip6_flow = 0;
2511         ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
2512         ip6->ip6_vfc |= IPV6_VERSION;
2513         /* ip6->ip6_plen will be set later */
2514         ip6->ip6_nxt = IPPROTO_ICMPV6;
2515         ip6->ip6_hlim = 255;
2516         /* ip6->ip6_src must be linklocal addr for my outgoing if. */
2517         bcopy(ifp_ll6, &ip6->ip6_src, sizeof(struct in6_addr));
2518         bcopy(&sip6->ip6_src, &ip6->ip6_dst, sizeof(struct in6_addr));
2519
2520         /* ND Redirect */
2521         nd_rd = (struct nd_redirect *)(ip6 + 1);
2522         nd_rd->nd_rd_type = ND_REDIRECT;
2523         nd_rd->nd_rd_code = 0;
2524         nd_rd->nd_rd_reserved = 0;
2525         if (nh->nh_flags & NHF_GATEWAY) {
2526                 /*
2527                  * nd_rd->nd_rd_target must be a link-local address in
2528                  * better router cases.
2529                  */
2530                 if (!router_ll6)
2531                         goto fail;
2532                 bcopy(router_ll6, &nd_rd->nd_rd_target,
2533                     sizeof(nd_rd->nd_rd_target));
2534                 bcopy(&sip6->ip6_dst, &nd_rd->nd_rd_dst,
2535                     sizeof(nd_rd->nd_rd_dst));
2536         } else {
2537                 /* make sure redtgt == reddst */
2538                 bcopy(&sip6->ip6_dst, &nd_rd->nd_rd_target,
2539                     sizeof(nd_rd->nd_rd_target));
2540                 bcopy(&sip6->ip6_dst, &nd_rd->nd_rd_dst,
2541                     sizeof(nd_rd->nd_rd_dst));
2542         }
2543
2544         p = (u_char *)(nd_rd + 1);
2545
2546         if (!router_ll6)
2547                 goto nolladdropt;
2548
2549         {
2550                 /* target lladdr option */
2551                 int len;
2552                 struct nd_opt_hdr *nd_opt;
2553                 char *lladdr;
2554
2555                 ln = nd6_lookup(router_ll6, 0, ifp);
2556                 if (ln == NULL)
2557                         goto nolladdropt;
2558
2559                 len = sizeof(*nd_opt) + ifp->if_addrlen;
2560                 len = (len + 7) & ~7;   /* round by 8 */
2561                 /* safety check */
2562                 if (len + (p - (u_char *)ip6) > maxlen)
2563                         goto nolladdropt;
2564
2565                 if (ln->la_flags & LLE_VALID) {
2566                         nd_opt = (struct nd_opt_hdr *)p;
2567                         nd_opt->nd_opt_type = ND_OPT_TARGET_LINKADDR;
2568                         nd_opt->nd_opt_len = len >> 3;
2569                         lladdr = (char *)(nd_opt + 1);
2570                         bcopy(ln->ll_addr, lladdr, ifp->if_addrlen);
2571                         p += len;
2572                 }
2573         }
2574 nolladdropt:
2575         if (ln != NULL)
2576                 LLE_RUNLOCK(ln);
2577
2578         m->m_pkthdr.len = m->m_len = p - (u_char *)ip6;
2579
2580         /* just to be safe */
2581 #ifdef M_DECRYPTED      /*not openbsd*/
2582         if (m0->m_flags & M_DECRYPTED)
2583                 goto noredhdropt;
2584 #endif
2585         if (p - (u_char *)ip6 > maxlen)
2586                 goto noredhdropt;
2587
2588         {
2589                 /* redirected header option */
2590                 int len;
2591                 struct nd_opt_rd_hdr *nd_opt_rh;
2592
2593                 /*
2594                  * compute the maximum size for icmp6 redirect header option.
2595                  * XXX room for auth header?
2596                  */
2597                 len = maxlen - (p - (u_char *)ip6);
2598                 len &= ~7;
2599
2600                 /* This is just for simplicity. */
2601                 if (m0->m_pkthdr.len != m0->m_len) {
2602                         if (m0->m_next) {
2603                                 m_freem(m0->m_next);
2604                                 m0->m_next = NULL;
2605                         }
2606                         m0->m_pkthdr.len = m0->m_len;
2607                 }
2608
2609                 /*
2610                  * Redirected header option spec (RFC2461 4.6.3) talks nothing
2611                  * about padding/truncate rule for the original IP packet.
2612                  * From the discussion on IPv6imp in Feb 1999,
2613                  * the consensus was:
2614                  * - "attach as much as possible" is the goal
2615                  * - pad if not aligned (original size can be guessed by
2616                  *   original ip6 header)
2617                  * Following code adds the padding if it is simple enough,
2618                  * and truncates if not.
2619                  */
2620                 if (m0->m_next || m0->m_pkthdr.len != m0->m_len)
2621                         panic("assumption failed in %s:%d", __FILE__,
2622                             __LINE__);
2623
2624                 if (len - sizeof(*nd_opt_rh) < m0->m_pkthdr.len) {
2625                         /* not enough room, truncate */
2626                         m0->m_pkthdr.len = m0->m_len = len -
2627                             sizeof(*nd_opt_rh);
2628                 } else {
2629                         /* enough room, pad or truncate */
2630                         size_t extra;
2631
2632                         extra = m0->m_pkthdr.len % 8;
2633                         if (extra) {
2634                                 /* pad if easy enough, truncate if not */
2635                                 if (8 - extra <= M_TRAILINGSPACE(m0)) {
2636                                         /* pad */
2637                                         m0->m_len += (8 - extra);
2638                                         m0->m_pkthdr.len += (8 - extra);
2639                                 } else {
2640                                         /* truncate */
2641                                         m0->m_pkthdr.len -= extra;
2642                                         m0->m_len -= extra;
2643                                 }
2644                         }
2645                         len = m0->m_pkthdr.len + sizeof(*nd_opt_rh);
2646                         m0->m_pkthdr.len = m0->m_len = len -
2647                             sizeof(*nd_opt_rh);
2648                 }
2649
2650                 nd_opt_rh = (struct nd_opt_rd_hdr *)p;
2651                 bzero(nd_opt_rh, sizeof(*nd_opt_rh));
2652                 nd_opt_rh->nd_opt_rh_type = ND_OPT_REDIRECTED_HEADER;
2653                 nd_opt_rh->nd_opt_rh_len = len >> 3;
2654                 p += sizeof(*nd_opt_rh);
2655                 m->m_pkthdr.len = m->m_len = p - (u_char *)ip6;
2656
2657                 /* connect m0 to m */
2658                 m_tag_delete_chain(m0, NULL);
2659                 m0->m_flags &= ~M_PKTHDR;
2660                 m->m_next = m0;
2661                 m->m_pkthdr.len = m->m_len + m0->m_len;
2662                 m0 = NULL;
2663         }
2664 noredhdropt:;
2665         if (m0) {
2666                 m_freem(m0);
2667                 m0 = NULL;
2668         }
2669
2670         /* XXX: clear embedded link IDs in the inner header */
2671         in6_clearscope(&sip6->ip6_src);
2672         in6_clearscope(&sip6->ip6_dst);
2673         in6_clearscope(&nd_rd->nd_rd_target);
2674         in6_clearscope(&nd_rd->nd_rd_dst);
2675
2676         ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
2677
2678         nd_rd->nd_rd_cksum = 0;
2679         nd_rd->nd_rd_cksum = in6_cksum(m, IPPROTO_ICMPV6,
2680             sizeof(*ip6), ntohs(ip6->ip6_plen));
2681
2682         if (send_sendso_input_hook != NULL) {
2683                 mtag = m_tag_get(PACKET_TAG_ND_OUTGOING, sizeof(unsigned short),
2684                         M_NOWAIT);
2685                 if (mtag == NULL)
2686                         goto fail;
2687                 *(unsigned short *)(mtag + 1) = nd_rd->nd_rd_type;
2688                 m_tag_prepend(m, mtag);
2689         }
2690
2691         /* send the packet to outside... */
2692         ip6_output(m, NULL, NULL, 0, NULL, &outif, NULL);
2693         if (outif) {
2694                 icmp6_ifstat_inc(outif, ifs6_out_msg);
2695                 icmp6_ifstat_inc(outif, ifs6_out_redirect);
2696         }
2697         ICMP6STAT_INC(icp6s_outhist[ND_REDIRECT]);
2698
2699         return;
2700
2701 fail:
2702         if (m)
2703                 m_freem(m);
2704         if (m0)
2705                 m_freem(m0);
2706 }
2707
2708 /*
2709  * ICMPv6 socket option processing.
2710  */
2711 int
2712 icmp6_ctloutput(struct socket *so, struct sockopt *sopt)
2713 {
2714         int error = 0;
2715         int optlen;
2716         struct inpcb *inp = sotoinpcb(so);
2717         int level, op, optname;
2718
2719         if (sopt) {
2720                 level = sopt->sopt_level;
2721                 op = sopt->sopt_dir;
2722                 optname = sopt->sopt_name;
2723                 optlen = sopt->sopt_valsize;
2724         } else
2725                 level = op = optname = optlen = 0;
2726
2727         if (level != IPPROTO_ICMPV6) {
2728                 return EINVAL;
2729         }
2730
2731         switch (op) {
2732         case PRCO_SETOPT:
2733                 switch (optname) {
2734                 case ICMP6_FILTER:
2735                     {
2736                         struct icmp6_filter ic6f;
2737
2738                         if (optlen != sizeof(ic6f)) {
2739                                 error = EMSGSIZE;
2740                                 break;
2741                         }
2742                         error = sooptcopyin(sopt, &ic6f, optlen, optlen);
2743                         if (error == 0) {
2744                                 INP_WLOCK(inp);
2745                                 *inp->in6p_icmp6filt = ic6f;
2746                                 INP_WUNLOCK(inp);
2747                         }
2748                         break;
2749                     }
2750
2751                 default:
2752                         error = ENOPROTOOPT;
2753                         break;
2754                 }
2755                 break;
2756
2757         case PRCO_GETOPT:
2758                 switch (optname) {
2759                 case ICMP6_FILTER:
2760                     {
2761                         struct icmp6_filter ic6f;
2762
2763                         INP_RLOCK(inp);
2764                         ic6f = *inp->in6p_icmp6filt;
2765                         INP_RUNLOCK(inp);
2766                         error = sooptcopyout(sopt, &ic6f, sizeof(ic6f));
2767                         break;
2768                     }
2769
2770                 default:
2771                         error = ENOPROTOOPT;
2772                         break;
2773                 }
2774                 break;
2775         }
2776
2777         return (error);
2778 }
2779
2780 /*
2781  * Perform rate limit check.
2782  * Returns 0 if it is okay to send the icmp6 packet.
2783  * Returns 1 if the router SHOULD NOT send this icmp6 packet due to rate
2784  * limitation.
2785  *
2786  * XXX per-destination/type check necessary?
2787  *
2788  * dst - not used at this moment
2789  * type - not used at this moment
2790  * code - not used at this moment
2791  */
2792 static int
2793 icmp6_ratelimit(const struct in6_addr *dst, const int type,
2794     const int code)
2795 {
2796         int ret;
2797
2798         ret = 0;        /* okay to send */
2799
2800         /* PPS limit */
2801         if (!ppsratecheck(&V_icmp6errppslim_last, &V_icmp6errpps_count,
2802             V_icmp6errppslim)) {
2803                 /* The packet is subject to rate limit */
2804                 ret++;
2805         }
2806
2807         return ret;
2808 }