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/ip6_var.h>
 111 #include <netinet6/scope6_var.h>
 112 #include <netinet6/mld6_var.h>
 113 #include <netinet6/nd6.h>
 114 #include <netinet6/send.h>
 115
 116 extern ip6proto_ctlinput_t      *ip6_ctlprotox[];
 117
 118 VNET_PCPUSTAT_DEFINE(struct icmp6stat, icmp6stat);
 119 VNET_PCPUSTAT_SYSINIT(icmp6stat);
 120
 121 #ifdef VIMAGE
 122 VNET_PCPUSTAT_SYSUNINIT(icmp6stat);
 123 #endif /* VIMAGE */
 124
 125 VNET_DECLARE(struct inpcbinfo, ripcbinfo);
 126 VNET_DECLARE(int, icmp6errppslim);
 127 VNET_DEFINE_STATIC(int, icmp6errpps_count) = 0;
 128 VNET_DEFINE_STATIC(struct timeval, icmp6errppslim_last);
 129 VNET_DECLARE(int, icmp6_nodeinfo);
 130
 131 #define V_ripcbinfo                     VNET(ripcbinfo)
 132 #define V_icmp6errppslim                VNET(icmp6errppslim)
 133 #define V_icmp6errpps_count             VNET(icmp6errpps_count)
 134 #define V_icmp6errppslim_last           VNET(icmp6errppslim_last)
 135 #define V_icmp6_nodeinfo                VNET(icmp6_nodeinfo)
 136
 137 static void icmp6_errcount(int, int);
 138 static int icmp6_rip6_input(struct mbuf **, int);
 139 static void icmp6_reflect(struct mbuf *, size_t);
 140 static const char *icmp6_redirect_diag(struct in6_addr *,
 141         struct in6_addr *, struct in6_addr *);
 142 static struct mbuf *ni6_input(struct mbuf *, int, struct prison *);
 143 static struct mbuf *ni6_nametodns(const char *, int, int);
 144 static int ni6_dnsmatch(const char *, int, const char *, int);
 145 static int ni6_addrs(struct icmp6_nodeinfo *, struct mbuf *,
 146                           struct ifnet **, struct in6_addr *);
 147 static int ni6_store_addrs(struct icmp6_nodeinfo *, struct icmp6_nodeinfo *,
 148                                 struct ifnet *, int);
 149 static int icmp6_notify_error(struct mbuf **, int, int);
 150
 151 /*
 152  * Kernel module interface for updating icmp6stat.  The argument is an index
 153  * into icmp6stat treated as an array of u_quad_t.  While this encodes the
 154  * general layout of icmp6stat into the caller, it doesn't encode its
 155  * location, so that future changes to add, for example, per-CPU stats
 156  * support won't cause binary compatibility problems for kernel modules.
 157  */
 158 void
 159 kmod_icmp6stat_inc(int statnum)
 160 {
 161
 162         counter_u64_add(VNET(icmp6stat)[statnum], 1);
 163 }
 164
 165 static void
 166 icmp6_errcount(int type, int code)
 167 {
 168         switch (type) {
 169         case ICMP6_DST_UNREACH:
 170                 switch (code) {
 171                 case ICMP6_DST_UNREACH_NOROUTE:
 172                         ICMP6STAT_INC(icp6s_odst_unreach_noroute);
 173                         return;
 174                 case ICMP6_DST_UNREACH_ADMIN:
 175                         ICMP6STAT_INC(icp6s_odst_unreach_admin);
 176                         return;
 177                 case ICMP6_DST_UNREACH_BEYONDSCOPE:
 178                         ICMP6STAT_INC(icp6s_odst_unreach_beyondscope);
 179                         return;
 180                 case ICMP6_DST_UNREACH_ADDR:
 181                         ICMP6STAT_INC(icp6s_odst_unreach_addr);
 182                         return;
 183                 case ICMP6_DST_UNREACH_NOPORT:
 184                         ICMP6STAT_INC(icp6s_odst_unreach_noport);
 185                         return;
 186                 }
 187                 break;
 188         case ICMP6_PACKET_TOO_BIG:
 189                 ICMP6STAT_INC(icp6s_opacket_too_big);
 190                 return;
 191         case ICMP6_TIME_EXCEEDED:
 192                 switch (code) {
 193                 case ICMP6_TIME_EXCEED_TRANSIT:
 194                         ICMP6STAT_INC(icp6s_otime_exceed_transit);
 195                         return;
 196                 case ICMP6_TIME_EXCEED_REASSEMBLY:
 197                         ICMP6STAT_INC(icp6s_otime_exceed_reassembly);
 198                         return;
 199                 }
 200                 break;
 201         case ICMP6_PARAM_PROB:
 202                 switch (code) {
 203                 case ICMP6_PARAMPROB_HEADER:
 204                         ICMP6STAT_INC(icp6s_oparamprob_header);
 205                         return;
 206                 case ICMP6_PARAMPROB_NEXTHEADER:
 207                         ICMP6STAT_INC(icp6s_oparamprob_nextheader);
 208                         return;
 209                 case ICMP6_PARAMPROB_OPTION:
 210                         ICMP6STAT_INC(icp6s_oparamprob_option);
 211                         return;
 212                 }
 213                 break;
 214         case ND_REDIRECT:
 215                 ICMP6STAT_INC(icp6s_oredirect);
 216                 return;
 217         }
 218         ICMP6STAT_INC(icp6s_ounknown);
 219 }
 220
 221 /*
 222  * A wrapper function for icmp6_error() necessary when the erroneous packet
 223  * may not contain enough scope zone information.
 224  */
 225 void
 226 icmp6_error2(struct mbuf *m, int type, int code, int param,
 227     struct ifnet *ifp)
 228 {
 229         struct ip6_hdr *ip6;
 230
 231         if (ifp == NULL)
 232                 return;
 233
 234         if (m->m_len < sizeof(struct ip6_hdr)) {
 235                 m = m_pullup(m, sizeof(struct ip6_hdr));
 236                 if (m == NULL) {
 237                         IP6STAT_INC(ip6s_exthdrtoolong);
 238                         return;
 239                 }
 240         }
 241         ip6 = mtod(m, struct ip6_hdr *);
 242
 243         if (in6_setscope(&ip6->ip6_src, ifp, NULL) != 0)
 244                 return;
 245         if (in6_setscope(&ip6->ip6_dst, ifp, NULL) != 0)
 246                 return;
 247
 248         icmp6_error(m, type, code, param);
 249 }
 250
 251 /*
 252  * Generate an error packet of type error in response to bad IP6 packet.
 253  */
 254 void
 255 icmp6_error(struct mbuf *m, int type, int code, int param)
 256 {
 257         struct ip6_hdr *oip6, *nip6;
 258         struct icmp6_hdr *icmp6;
 259         struct epoch_tracker et;
 260         u_int preplen;
 261         int off;
 262         int nxt;
 263
 264         ICMP6STAT_INC(icp6s_error);
 265
 266         /* count per-type-code statistics */
 267         icmp6_errcount(type, code);
 268
 269 #ifdef M_DECRYPTED      /*not openbsd*/
 270         if (m->m_flags & M_DECRYPTED) {
 271                 ICMP6STAT_INC(icp6s_canterror);
 272                 goto freeit;
 273         }
 274 #endif
 275
 276         if (m->m_len < sizeof(struct ip6_hdr)) {
 277                 m = m_pullup(m, sizeof(struct ip6_hdr));
 278                 if (m == NULL) {
 279                         IP6STAT_INC(ip6s_exthdrtoolong);
 280                         return;
 281                 }
 282         }
 283         oip6 = mtod(m, struct ip6_hdr *);
 284
 285         /*
 286          * If the destination address of the erroneous packet is a multicast
 287          * address, or the packet was sent using link-layer multicast,
 288          * we should basically suppress sending an error (RFC 2463, Section
 289          * 2.4).
 290          * We have two exceptions (the item e.2 in that section):
 291          * - the Packet Too Big message can be sent for path MTU discovery.
 292          * - the Parameter Problem Message that can be allowed an icmp6 error
 293          *   in the option type field.  This check has been done in
 294          *   ip6_unknown_opt(), so we can just check the type and code.
 295          */
 296         if ((m->m_flags & (M_BCAST|M_MCAST) ||
 297              IN6_IS_ADDR_MULTICAST(&oip6->ip6_dst)) &&
 298             (type != ICMP6_PACKET_TOO_BIG &&
 299              (type != ICMP6_PARAM_PROB ||
 300               code != ICMP6_PARAMPROB_OPTION)))
 301                 goto freeit;
 302
 303         /*
 304          * RFC 2463, 2.4 (e.5): source address check.
 305          * XXX: the case of anycast source?
 306          */
 307         if (IN6_IS_ADDR_UNSPECIFIED(&oip6->ip6_src) ||
 308             IN6_IS_ADDR_MULTICAST(&oip6->ip6_src))
 309                 goto freeit;
 310
 311         /*
 312          * If we are about to send ICMPv6 against ICMPv6 error/redirect,
 313          * don't do it.
 314          */
 315         nxt = -1;
 316         off = ip6_lasthdr(m, 0, IPPROTO_IPV6, &nxt);
 317         if (off >= 0 && nxt == IPPROTO_ICMPV6) {
 318                 struct icmp6_hdr *icp;
 319
 320                 if (m->m_len < off + sizeof(struct icmp6_hdr)) {
 321                         m = m_pullup(m, off + sizeof(struct icmp6_hdr));
 322                         if (m == NULL) {
 323                                 IP6STAT_INC(ip6s_exthdrtoolong);
 324                                 return;
 325                         }
 326                 }
 327                 oip6 = mtod(m, struct ip6_hdr *);
 328                 icp = (struct icmp6_hdr *)(mtod(m, caddr_t) + off);
 329
 330                 if (icp->icmp6_type < ICMP6_ECHO_REQUEST ||
 331                     icp->icmp6_type == ND_REDIRECT) {
 332                         /*
 333                          * ICMPv6 error
 334                          * Special case: for redirect (which is
 335                          * informational) we must not send icmp6 error.
 336                          */
 337                         ICMP6STAT_INC(icp6s_canterror);
 338                         goto freeit;
 339                 } else {
 340                         /* ICMPv6 informational - send the error */
 341                 }
 342         } else {
 343                 /* non-ICMPv6 - send the error */
 344         }
 345
 346         /* Finally, do rate limitation check. */
 347         if (icmp6_ratelimit(&oip6->ip6_src, type, code)) {
 348                 ICMP6STAT_INC(icp6s_toofreq);
 349                 goto freeit;
 350         }
 351
 352         /*
 353          * OK, ICMP6 can be generated.
 354          */
 355
 356         if (m->m_pkthdr.len >= ICMPV6_PLD_MAXLEN)
 357                 m_adj(m, ICMPV6_PLD_MAXLEN - m->m_pkthdr.len);
 358
 359         preplen = sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr);
 360         M_PREPEND(m, preplen, M_NOWAIT);        /* FIB is also copied over. */
 361         if (m == NULL) {
 362                 nd6log((LOG_DEBUG, "ENOBUFS in icmp6_error %d\n", __LINE__));
 363                 return;
 364         }
 365
 366         nip6 = mtod(m, struct ip6_hdr *);
 367         nip6->ip6_src  = oip6->ip6_src;
 368         nip6->ip6_dst  = oip6->ip6_dst;
 369
 370         in6_clearscope(&oip6->ip6_src);
 371         in6_clearscope(&oip6->ip6_dst);
 372
 373         icmp6 = (struct icmp6_hdr *)(nip6 + 1);
 374         icmp6->icmp6_type = type;
 375         icmp6->icmp6_code = code;
 376         icmp6->icmp6_pptr = htonl((u_int32_t)param);
 377
 378         ICMP6STAT_INC(icp6s_outhist[type]);
 379         NET_EPOCH_ENTER(et);
 380         icmp6_reflect(m, sizeof(struct ip6_hdr)); /* header order: IPv6 - ICMPv6 */
 381         NET_EPOCH_EXIT(et);
 382
 383         return;
 384
 385   freeit:
 386         /*
 387          * If we can't tell whether or not we can generate ICMP6, free it.
 388          */
 389         m_freem(m);
 390 }
 391
 392 int
 393 icmp6_errmap(const struct icmp6_hdr *icmp6)
 394 {
 395
 396         switch (icmp6->icmp6_type) {
 397         case ICMP6_DST_UNREACH:
 398                 switch (icmp6->icmp6_code) {
 399                 case ICMP6_DST_UNREACH_NOROUTE:
 400                 case ICMP6_DST_UNREACH_ADDR:
 401                         return (EHOSTUNREACH);
 402                 case ICMP6_DST_UNREACH_NOPORT:
 403                 case ICMP6_DST_UNREACH_ADMIN:
 404                         return (ECONNREFUSED);
 405                 case ICMP6_DST_UNREACH_BEYONDSCOPE:
 406                         return (ENOPROTOOPT);
 407                 default:
 408                         return (0);     /* Shouldn't happen. */
 409                 }
 410         case ICMP6_PACKET_TOO_BIG:
 411                 return (EMSGSIZE);
 412         case ICMP6_TIME_EXCEEDED:
 413                 switch (icmp6->icmp6_code) {
 414                 case ICMP6_TIME_EXCEED_TRANSIT:
 415                         return (EHOSTUNREACH);
 416                 case ICMP6_TIME_EXCEED_REASSEMBLY:
 417                         return (0);
 418                 default:
 419                         return (0);     /* Shouldn't happen. */
 420                 }
 421         case ICMP6_PARAM_PROB:
 422                 switch (icmp6->icmp6_code) {
 423                 case ICMP6_PARAMPROB_NEXTHEADER:
 424                         return (ECONNREFUSED);
 425                 case ICMP6_PARAMPROB_HEADER:
 426                 case ICMP6_PARAMPROB_OPTION:
 427                         return (ENOPROTOOPT);
 428                 default:
 429                         return (0);     /* Shouldn't happen. */
 430                 }
 431         default:
 432                 return (0);
 433         }
 434 }
 435
 436 /*
 437  * Process a received ICMP6 message.
 438  */
 439 int
 440 icmp6_input(struct mbuf **mp, int *offp, int proto)
 441 {
 442         struct mbuf *m, *n;
 443         struct ifnet *ifp;
 444         struct ip6_hdr *ip6, *nip6;
 445         struct icmp6_hdr *icmp6, *nicmp6;
 446         char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
 447         int code, error, icmp6len, ip6len, noff, off, sum;
 448
 449         NET_EPOCH_ASSERT();
 450
 451         m = *mp;
 452         off = *offp;
 453
 454         if (m->m_len < off + sizeof(struct icmp6_hdr)) {
 455                 m = m_pullup(m, off + sizeof(struct icmp6_hdr));
 456                 if (m == NULL) {
 457                         IP6STAT_INC(ip6s_exthdrtoolong);
 458                         *mp = m;
 459                         return (IPPROTO_DONE);
 460                 }
 461         }
 462
 463         /*
 464          * Locate icmp6 structure in mbuf, and check
 465          * that not corrupted and of at least minimum length
 466          */
 467
 468         icmp6len = m->m_pkthdr.len - off;
 469         if (icmp6len < sizeof(struct icmp6_hdr)) {
 470                 ICMP6STAT_INC(icp6s_tooshort);
 471                 goto freeit;
 472         }
 473
 474         ip6 = mtod(m, struct ip6_hdr *);
 475         ifp = m->m_pkthdr.rcvif;
 476         /*
 477          * Check multicast group membership.
 478          * Note: SSM filters are not applied for ICMPv6 traffic.
 479          */
 480         if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
 481                 struct in6_multi        *inm;
 482
 483                 inm = in6m_lookup(ifp, &ip6->ip6_dst);
 484                 if (inm == NULL) {
 485                         IP6STAT_INC(ip6s_notmember);
 486                         in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
 487                         goto freeit;
 488                 }
 489         }
 490
 491         /* Calculate the checksum. */
 492         icmp6 = (struct icmp6_hdr *)((caddr_t)ip6 + off);
 493         code = icmp6->icmp6_code;
 494         if ((sum = in6_cksum(m, IPPROTO_ICMPV6, off, icmp6len)) != 0) {
 495                 nd6log((LOG_ERR,
 496                     "ICMP6 checksum error(%d|%x) %s\n",
 497                     icmp6->icmp6_type, sum,
 498                     ip6_sprintf(ip6bufs, &ip6->ip6_src)));
 499                 ICMP6STAT_INC(icp6s_checksum);
 500                 goto freeit;
 501         }
 502
 503         ICMP6STAT_INC(icp6s_inhist[icmp6->icmp6_type]);
 504         icmp6_ifstat_inc(ifp, ifs6_in_msg);
 505         if (icmp6->icmp6_type < ICMP6_INFOMSG_MASK)
 506                 icmp6_ifstat_inc(ifp, ifs6_in_error);
 507
 508         ip6len = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen);
 509         switch (icmp6->icmp6_type) {
 510         case ICMP6_DST_UNREACH:
 511                 icmp6_ifstat_inc(ifp, ifs6_in_dstunreach);
 512                 switch (code) {
 513                 case ICMP6_DST_UNREACH_ADMIN:
 514                         icmp6_ifstat_inc(ifp, ifs6_in_adminprohib);
 515                 case ICMP6_DST_UNREACH_NOROUTE:
 516                 case ICMP6_DST_UNREACH_ADDR:
 517                 case ICMP6_DST_UNREACH_BEYONDSCOPE:
 518                 case ICMP6_DST_UNREACH_NOPORT:
 519                         goto deliver;
 520                 default:
 521                         goto badcode;
 522                 }
 523         case ICMP6_PACKET_TOO_BIG:
 524                 icmp6_ifstat_inc(ifp, ifs6_in_pkttoobig);
 525                 /*
 526                  * Validation is made in icmp6_mtudisc_update.
 527                  * Updating the path MTU will be done after examining
 528                  * intermediate extension headers.
 529                  */
 530                 goto deliver;
 531         case ICMP6_TIME_EXCEEDED:
 532                 icmp6_ifstat_inc(ifp, ifs6_in_timeexceed);
 533                 switch (code) {
 534                 case ICMP6_TIME_EXCEED_TRANSIT:
 535                 case ICMP6_TIME_EXCEED_REASSEMBLY:
 536                         goto deliver;
 537                 default:
 538                         goto badcode;
 539                 }
 540         case ICMP6_PARAM_PROB:
 541                 icmp6_ifstat_inc(ifp, ifs6_in_paramprob);
 542                 switch (code) {
 543                 case ICMP6_PARAMPROB_NEXTHEADER:
 544                 case ICMP6_PARAMPROB_HEADER:
 545                 case ICMP6_PARAMPROB_OPTION:
 546                         goto deliver;
 547                 default:
 548                         goto badcode;
 549                 }
 550         case ICMP6_ECHO_REQUEST:
 551                 icmp6_ifstat_inc(ifp, ifs6_in_echo);
 552                 if (code != 0)
 553                         goto badcode;
 554                 if ((n = m_copym(m, 0, M_COPYALL, M_NOWAIT)) == NULL) {
 555                         /* Give up remote */
 556                         break;
 557                 }
 558                 if (!M_WRITABLE(n)
 559                  || n->m_len < off + sizeof(struct icmp6_hdr)) {
 560                         struct mbuf *n0 = n;
 561                         int n0len;
 562
 563                         CTASSERT(sizeof(*nip6) + sizeof(*nicmp6) <= MHLEN);
 564                         n = m_gethdr(M_NOWAIT, n0->m_type);
 565                         if (n == NULL) {
 566                                 /* Give up remote */
 567                                 m_freem(n0);
 568                                 break;
 569                         }
 570
 571                         m_move_pkthdr(n, n0);   /* FIB copied. */
 572                         n0len = n0->m_pkthdr.len;       /* save for use below */
 573                         /*
 574                          * Copy IPv6 and ICMPv6 only.
 575                          */
 576                         nip6 = mtod(n, struct ip6_hdr *);
 577                         bcopy(ip6, nip6, sizeof(struct ip6_hdr));
 578                         nicmp6 = (struct icmp6_hdr *)(nip6 + 1);
 579                         bcopy(icmp6, nicmp6, sizeof(struct icmp6_hdr));
 580                         noff = sizeof(struct ip6_hdr);
 581                         /* new mbuf contains only ipv6+icmpv6 headers */
 582                         n->m_len = noff + sizeof(struct icmp6_hdr);
 583                         /*
 584                          * Adjust mbuf.  ip6_plen will be adjusted in
 585                          * ip6_output().
 586                          */
 587                         m_adj(n0, off + sizeof(struct icmp6_hdr));
 588                         /* recalculate complete packet size */
 589                         n->m_pkthdr.len = n0len + (noff - off);
 590                         n->m_next = n0;
 591                 } else {
 592                         if (n->m_len < off + sizeof(*nicmp6)) {
 593                                 n = m_pullup(n, off + sizeof(*nicmp6));
 594                                 if (n == NULL) {
 595                                         IP6STAT_INC(ip6s_exthdrtoolong);
 596                                         break;
 597                                 }
 598                         }
 599                         nicmp6 = (struct icmp6_hdr *)(mtod(n, caddr_t) + off);
 600                         noff = off;
 601                 }
 602                 if (n) {
 603                         nicmp6->icmp6_type = ICMP6_ECHO_REPLY;
 604                         nicmp6->icmp6_code = 0;
 605                         ICMP6STAT_INC(icp6s_reflect);
 606                         ICMP6STAT_INC(icp6s_outhist[ICMP6_ECHO_REPLY]);
 607                         icmp6_reflect(n, noff);
 608                 }
 609                 break;
 610
 611         case ICMP6_ECHO_REPLY:
 612                 icmp6_ifstat_inc(ifp, ifs6_in_echoreply);
 613                 if (code != 0)
 614                         goto badcode;
 615                 break;
 616
 617         case MLD_LISTENER_QUERY:
 618         case MLD_LISTENER_REPORT:
 619         case MLD_LISTENER_DONE:
 620         case MLDV2_LISTENER_REPORT:
 621                 /*
 622                  * Drop MLD traffic which is not link-local, has a hop limit
 623                  * of greater than 1 hop, or which does not have the
 624                  * IPv6 HBH Router Alert option.
 625                  * As IPv6 HBH options are stripped in ip6_input() we must
 626                  * check an mbuf header flag.
 627                  * XXX Should we also sanity check that these messages
 628                  * were directed to a link-local multicast prefix?
 629                  */
 630                 if ((ip6->ip6_hlim != 1) || (m->m_flags & M_RTALERT_MLD) == 0)
 631                         goto freeit;
 632                 if (mld_input(&m, off, icmp6len) != 0) {
 633                         *mp = NULL;
 634                         return (IPPROTO_DONE);
 635                 }
 636                 /* m stays. */
 637                 break;
 638
 639         case ICMP6_WRUREQUEST:  /* ICMP6_FQDN_QUERY */
 640             {
 641                 enum { WRU, FQDN } mode;
 642                 struct prison *pr;
 643
 644                 if (!V_icmp6_nodeinfo)
 645                         break;
 646
 647                 if (icmp6len == sizeof(struct icmp6_hdr) + 4)
 648                         mode = WRU;
 649                 else if (icmp6len >= sizeof(struct icmp6_nodeinfo))
 650                         mode = FQDN;
 651                 else
 652                         goto badlen;
 653
 654                 pr = NULL;
 655                 sx_slock(&allprison_lock);
 656                 TAILQ_FOREACH(pr, &allprison, pr_list)
 657                         if (pr->pr_vnet == ifp->if_vnet)
 658                                 break;
 659                 sx_sunlock(&allprison_lock);
 660                 if (pr == NULL)
 661                         pr = curthread->td_ucred->cr_prison;
 662                 if (mode == FQDN) {
 663                         if (m->m_len < off + sizeof(struct icmp6_nodeinfo)) {
 664                                 m = m_pullup(m, off +
 665                                     sizeof(struct icmp6_nodeinfo));
 666                                 if (m == NULL) {
 667                                         IP6STAT_INC(ip6s_exthdrtoolong);
 668                                         *mp = m;
 669                                         return (IPPROTO_DONE);
 670                                 }
 671                         }
 672                         n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
 673                         if (n)
 674                                 n = ni6_input(n, off, pr);
 675                         /* XXX meaningless if n == NULL */
 676                         noff = sizeof(struct ip6_hdr);
 677                 } else {
 678                         u_char *p;
 679                         int maxhlen, hlen;
 680
 681                         /*
 682                          * XXX: this combination of flags is pointless,
 683                          * but should we keep this for compatibility?
 684                          */
 685                         if ((V_icmp6_nodeinfo & (ICMP6_NODEINFO_FQDNOK |
 686                             ICMP6_NODEINFO_TMPADDROK)) !=
 687                             (ICMP6_NODEINFO_FQDNOK | ICMP6_NODEINFO_TMPADDROK))
 688                                 break;
 689
 690                         if (code != 0)
 691                                 goto badcode;
 692
 693                         CTASSERT(sizeof(*nip6) + sizeof(*nicmp6) + 4 <= MHLEN);
 694                         n = m_gethdr(M_NOWAIT, m->m_type);
 695                         if (n == NULL) {
 696                                 /* Give up remote */
 697                                 break;
 698                         }
 699                         if (!m_dup_pkthdr(n, m, M_NOWAIT)) {
 700                                 /*
 701                                  * Previous code did a blind M_COPY_PKTHDR
 702                                  * and said "just for rcvif".  If true, then
 703                                  * we could tolerate the dup failing (due to
 704                                  * the deep copy of the tag chain).  For now
 705                                  * be conservative and just fail.
 706                                  */
 707                                 m_free(n);
 708                                 n = NULL;
 709                                 break;
 710                         }
 711                         /*
 712                          * Copy IPv6 and ICMPv6 only.
 713                          */
 714                         nip6 = mtod(n, struct ip6_hdr *);
 715                         bcopy(ip6, nip6, sizeof(struct ip6_hdr));
 716                         nicmp6 = (struct icmp6_hdr *)(nip6 + 1);
 717                         bcopy(icmp6, nicmp6, sizeof(struct icmp6_hdr));
 718                         p = (u_char *)(nicmp6 + 1);
 719                         bzero(p, 4);
 720
 721                         maxhlen = M_TRAILINGSPACE(n) -
 722                             (sizeof(*nip6) + sizeof(*nicmp6) + 4);
 723                         mtx_lock(&pr->pr_mtx);
 724                         hlen = strlen(pr->pr_hostname);
 725                         if (maxhlen > hlen)
 726                                 maxhlen = hlen;
 727                         /* meaningless TTL */
 728                         bcopy(pr->pr_hostname, p + 4, maxhlen);
 729                         mtx_unlock(&pr->pr_mtx);
 730                         noff = sizeof(struct ip6_hdr);
 731                         n->m_pkthdr.len = n->m_len = sizeof(struct ip6_hdr) +
 732                                 sizeof(struct icmp6_hdr) + 4 + maxhlen;
 733                         nicmp6->icmp6_type = ICMP6_WRUREPLY;
 734                         nicmp6->icmp6_code = 0;
 735                 }
 736                 if (n) {
 737                         ICMP6STAT_INC(icp6s_reflect);
 738                         ICMP6STAT_INC(icp6s_outhist[ICMP6_WRUREPLY]);
 739                         icmp6_reflect(n, noff);
 740                 }
 741                 break;
 742             }
 743
 744         case ICMP6_WRUREPLY:
 745                 if (code != 0)
 746                         goto badcode;
 747                 break;
 748
 749         case ND_ROUTER_SOLICIT:
 750                 icmp6_ifstat_inc(ifp, ifs6_in_routersolicit);
 751                 if (code != 0)
 752                         goto badcode;
 753                 if (icmp6len < sizeof(struct nd_router_solicit))
 754                         goto badlen;
 755                 if (send_sendso_input_hook != NULL) {
 756                         if (m->m_len < off + icmp6len) {
 757                                 m = m_pullup(m, off + icmp6len);
 758                                 if (m == NULL) {
 759                                         IP6STAT_INC(ip6s_exthdrtoolong);
 760                                         *mp = NULL;
 761                                         return (IPPROTO_DONE);
 762                                 }
 763                         }
 764                         error = send_sendso_input_hook(m, ifp, SND_IN, ip6len);
 765                         if (error == 0) {
 766                                 m = NULL;
 767                                 goto freeit;
 768                         }
 769                 }
 770                 n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
 771                 nd6_rs_input(m, off, icmp6len);
 772                 m = n;
 773                 if (m == NULL)
 774                         goto freeit;
 775                 break;
 776
 777         case ND_ROUTER_ADVERT:
 778                 icmp6_ifstat_inc(ifp, ifs6_in_routeradvert);
 779                 if (code != 0)
 780                         goto badcode;
 781                 if (icmp6len < sizeof(struct nd_router_advert))
 782                         goto badlen;
 783                 if (send_sendso_input_hook != NULL) {
 784                         error = send_sendso_input_hook(m, ifp, SND_IN, ip6len);
 785                         if (error == 0) {
 786                                 m = NULL;
 787                                 goto freeit;
 788                         }
 789                 }
 790                 n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
 791                 nd6_ra_input(m, off, icmp6len);
 792                 m = n;
 793                 if (m == NULL)
 794                         goto freeit;
 795                 break;
 796
 797         case ND_NEIGHBOR_SOLICIT:
 798                 icmp6_ifstat_inc(ifp, ifs6_in_neighborsolicit);
 799                 if (code != 0)
 800                         goto badcode;
 801                 if (icmp6len < sizeof(struct nd_neighbor_solicit))
 802                         goto badlen;
 803                 if (send_sendso_input_hook != NULL) {
 804                         error = send_sendso_input_hook(m, ifp, SND_IN, ip6len);
 805                         if (error == 0) {
 806                                 m = NULL;
 807                                 goto freeit;
 808                         }
 809                 }
 810                 n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
 811                 nd6_ns_input(m, off, icmp6len);
 812                 m = n;
 813                 if (m == NULL)
 814                         goto freeit;
 815                 break;
 816
 817         case ND_NEIGHBOR_ADVERT:
 818                 icmp6_ifstat_inc(ifp, ifs6_in_neighboradvert);
 819                 if (code != 0)
 820                         goto badcode;
 821                 if (icmp6len < sizeof(struct nd_neighbor_advert))
 822                         goto badlen;
 823                 if (send_sendso_input_hook != NULL) {
 824                         error = send_sendso_input_hook(m, ifp, SND_IN, ip6len);
 825                         if (error == 0) {
 826                                 m = NULL;
 827                                 goto freeit;
 828                         }
 829                 }
 830                 n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
 831                 nd6_na_input(m, off, icmp6len);
 832                 m = n;
 833                 if (m == NULL)
 834                         goto freeit;
 835                 break;
 836
 837         case ND_REDIRECT:
 838                 icmp6_ifstat_inc(ifp, ifs6_in_redirect);
 839                 if (code != 0)
 840                         goto badcode;
 841                 if (icmp6len < sizeof(struct nd_redirect))
 842                         goto badlen;
 843                 if (send_sendso_input_hook != NULL) {
 844                         error = send_sendso_input_hook(m, ifp, SND_IN, ip6len);
 845                         if (error == 0) {
 846                                 m = NULL;
 847                                 goto freeit;
 848                         }
 849                 }
 850                 n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
 851                 icmp6_redirect_input(m, off);
 852                 m = n;
 853                 if (m == NULL)
 854                         goto freeit;
 855                 break;
 856
 857         case ICMP6_ROUTER_RENUMBERING:
 858                 if (code != ICMP6_ROUTER_RENUMBERING_COMMAND &&
 859                     code != ICMP6_ROUTER_RENUMBERING_RESULT)
 860                         goto badcode;
 861                 if (icmp6len < sizeof(struct icmp6_router_renum))
 862                         goto badlen;
 863                 break;
 864
 865         default:
 866                 nd6log((LOG_DEBUG,
 867                     "icmp6_input: unknown type %d(src=%s, dst=%s, ifid=%d)\n",
 868                     icmp6->icmp6_type, ip6_sprintf(ip6bufs, &ip6->ip6_src),
 869                     ip6_sprintf(ip6bufd, &ip6->ip6_dst),
 870                     ifp ? ifp->if_index : 0));
 871                 if (icmp6->icmp6_type < ICMP6_ECHO_REQUEST) {
 872                         /* ICMPv6 error: MUST deliver it by spec... */
 873                         goto deliver;
 874                 } else {
 875                         /* ICMPv6 informational: MUST not deliver */
 876                         break;
 877                 }
 878         deliver:
 879                 if (icmp6_notify_error(&m, off, icmp6len) != 0) {
 880                         /* In this case, m should've been freed. */
 881                         *mp = NULL;
 882                         return (IPPROTO_DONE);
 883                 }
 884                 break;
 885
 886         badcode:
 887                 ICMP6STAT_INC(icp6s_badcode);
 888                 break;
 889
 890         badlen:
 891                 ICMP6STAT_INC(icp6s_badlen);
 892                 break;
 893         }
 894
 895         /* deliver the packet to appropriate sockets */
 896         icmp6_rip6_input(&m, *offp);
 897
 898         *mp = m;
 899         return (IPPROTO_DONE);
 900
 901  freeit:
 902         m_freem(m);
 903         *mp = NULL;
 904         return (IPPROTO_DONE);
 905 }
 906
 907 static int
 908 icmp6_notify_error(struct mbuf **mp, int off, int icmp6len)
 909 {
 910         struct mbuf *m;
 911         struct icmp6_hdr *icmp6;
 912         struct ip6_hdr *eip6;
 913         u_int32_t notifymtu;
 914         struct sockaddr_in6 icmp6src, icmp6dst;
 915
 916         m = *mp;
 917
 918         if (icmp6len < sizeof(struct icmp6_hdr) + sizeof(struct ip6_hdr)) {
 919                 ICMP6STAT_INC(icp6s_tooshort);
 920                 goto freeit;
 921         }
 922
 923         if (m->m_len < off + sizeof(*icmp6) + sizeof(struct ip6_hdr)) {
 924                 m = m_pullup(m, off + sizeof(*icmp6) + sizeof(struct ip6_hdr));
 925                 if (m == NULL) {
 926                         IP6STAT_INC(ip6s_exthdrtoolong);
 927                         *mp = m;
 928                         return (-1);
 929                 }
 930         }
 931         icmp6 = (struct icmp6_hdr *)(mtod(m, caddr_t) + off);
 932         eip6 = (struct ip6_hdr *)(icmp6 + 1);
 933         bzero(&icmp6dst, sizeof(icmp6dst));
 934
 935         /* Detect the upper level protocol */
 936         {
 937                 u_int8_t nxt = eip6->ip6_nxt;
 938                 int eoff = off + sizeof(struct icmp6_hdr) +
 939                     sizeof(struct ip6_hdr);
 940                 struct ip6ctlparam ip6cp;
 941                 int icmp6type = icmp6->icmp6_type;
 942                 struct ip6_frag *fh;
 943                 struct ip6_rthdr *rth;
 944                 struct ip6_rthdr0 *rth0;
 945                 int rthlen;
 946
 947                 while (1) { /* XXX: should avoid infinite loop explicitly? */
 948                         struct ip6_ext *eh;
 949
 950                         switch (nxt) {
 951                         case IPPROTO_HOPOPTS:
 952                         case IPPROTO_DSTOPTS:
 953                         case IPPROTO_AH:
 954                                 if (m->m_len < eoff + sizeof(struct ip6_ext)) {
 955                                         m = m_pullup(m, eoff +
 956                                             sizeof(struct ip6_ext));
 957                                         if (m == NULL) {
 958                                                 IP6STAT_INC(ip6s_exthdrtoolong);
 959                                                 *mp = m;
 960                                                 return (-1);
 961                                         }
 962                                 }
 963                                 eh = (struct ip6_ext *)
 964                                     (mtod(m, caddr_t) + eoff);
 965                                 if (nxt == IPPROTO_AH)
 966                                         eoff += (eh->ip6e_len + 2) << 2;
 967                                 else
 968                                         eoff += (eh->ip6e_len + 1) << 3;
 969                                 nxt = eh->ip6e_nxt;
 970                                 break;
 971                         case IPPROTO_ROUTING:
 972                                 /*
 973                                  * When the erroneous packet contains a
 974                                  * routing header, we should examine the
 975                                  * header to determine the final destination.
 976                                  * Otherwise, we can't properly update
 977                                  * information that depends on the final
 978                                  * destination (e.g. path MTU).
 979                                  */
 980                                 if (m->m_len < eoff + sizeof(*rth)) {
 981                                         m = m_pullup(m, eoff + sizeof(*rth));
 982                                         if (m == NULL) {
 983                                                 IP6STAT_INC(ip6s_exthdrtoolong);
 984                                                 *mp = m;
 985                                                 return (-1);
 986                                         }
 987                                 }
 988                                 rth = (struct ip6_rthdr *)
 989                                     (mtod(m, caddr_t) + eoff);
 990                                 rthlen = (rth->ip6r_len + 1) << 3;
 991                                 /*
 992                                  * XXX: currently there is no
 993                                  * officially defined type other
 994                                  * than type-0.
 995                                  * Note that if the segment left field
 996                                  * is 0, all intermediate hops must
 997                                  * have been passed.
 998                                  */
 999                                 if (rth->ip6r_segleft &&
1000                                     rth->ip6r_type == IPV6_RTHDR_TYPE_0) {
1001                                         int hops;
1002
1003                                         if (m->m_len < eoff + rthlen) {
1004                                                 m = m_pullup(m, eoff + rthlen);
1005                                                 if (m == NULL) {
1006                                                         IP6STAT_INC(
1007                                                             ip6s_exthdrtoolong);
1008                                                         *mp = m;
1009                                                         return (-1);
1010                                                 }
1011                                         }
1012                                         rth0 = (struct ip6_rthdr0 *)
1013                                             (mtod(m, caddr_t) + eoff);
1014
1015                                         /* just ignore a bogus header */
1016                                         if ((rth0->ip6r0_len % 2) == 0 &&
1017                                             (hops = rth0->ip6r0_len/2))
1018                                                 icmp6dst.sin6_addr = *((struct in6_addr *)(rth0 + 1) + (hops - 1));
1019                                 }
1020                                 eoff += rthlen;
1021                                 nxt = rth->ip6r_nxt;
1022                                 break;
1023                         case IPPROTO_FRAGMENT:
1024                                 if (m->m_len < eoff + sizeof(struct ip6_frag)) {
1025                                         m = m_pullup(m, eoff +
1026                                             sizeof(struct ip6_frag));
1027                                         if (m == NULL) {
1028                                                 IP6STAT_INC(ip6s_exthdrtoolong);
1029                                                 *mp = m;
1030                                                 return (-1);
1031                                         }
1032                                 }
1033                                 fh = (struct ip6_frag *)(mtod(m, caddr_t) +
1034                                     eoff);
1035                                 /*
1036                                  * Data after a fragment header is meaningless
1037                                  * unless it is the first fragment, but
1038                                  * we'll go to the notify label for path MTU
1039                                  * discovery.
1040                                  */
1041                                 if (fh->ip6f_offlg & IP6F_OFF_MASK)
1042                                         goto notify;
1043
1044                                 eoff += sizeof(struct ip6_frag);
1045                                 nxt = fh->ip6f_nxt;
1046                                 break;
1047                         default:
1048                                 /*
1049                                  * This case includes ESP and the No Next
1050                                  * Header.  In such cases going to the notify
1051                                  * label does not have any meaning
1052                                  * (i.e. ctlfunc will be NULL), but we go
1053                                  * anyway since we might have to update
1054                                  * path MTU information.
1055                                  */
1056                                 goto notify;
1057                         }
1058                 }
1059           notify:
1060                 icmp6 = (struct icmp6_hdr *)(mtod(m, caddr_t) + off);
1061
1062                 /*
1063                  * retrieve parameters from the inner IPv6 header, and convert
1064                  * them into sockaddr structures.
1065                  * XXX: there is no guarantee that the source or destination
1066                  * addresses of the inner packet are in the same scope as
1067                  * the addresses of the icmp packet.  But there is no other
1068                  * way to determine the zone.
1069                  */
1070                 eip6 = (struct ip6_hdr *)(icmp6 + 1);
1071
1072                 icmp6dst.sin6_len = sizeof(struct sockaddr_in6);
1073                 icmp6dst.sin6_family = AF_INET6;
1074                 if (IN6_IS_ADDR_UNSPECIFIED(&icmp6dst.sin6_addr))
1075                         icmp6dst.sin6_addr = eip6->ip6_dst;
1076                 if (in6_setscope(&icmp6dst.sin6_addr, m->m_pkthdr.rcvif, NULL))
1077                         goto freeit;
1078                 bzero(&icmp6src, sizeof(icmp6src));
1079                 icmp6src.sin6_len = sizeof(struct sockaddr_in6);
1080                 icmp6src.sin6_family = AF_INET6;
1081                 icmp6src.sin6_addr = eip6->ip6_src;
1082                 if (in6_setscope(&icmp6src.sin6_addr, m->m_pkthdr.rcvif, NULL))
1083                         goto freeit;
1084                 icmp6src.sin6_flowinfo =
1085                     (eip6->ip6_flow & IPV6_FLOWLABEL_MASK);
1086
1087                 ip6cp.ip6c_m = m;
1088                 ip6cp.ip6c_icmp6 = icmp6;
1089                 ip6cp.ip6c_ip6 = (struct ip6_hdr *)(icmp6 + 1);
1090                 ip6cp.ip6c_off = eoff;
1091                 ip6cp.ip6c_finaldst = &icmp6dst;
1092                 ip6cp.ip6c_src = &icmp6src;
1093                 ip6cp.ip6c_nxt = nxt;
1094
1095                 if (icmp6type == ICMP6_PACKET_TOO_BIG) {
1096                         notifymtu = ntohl(icmp6->icmp6_mtu);
1097                         ip6cp.ip6c_cmdarg = (void *)&notifymtu;
1098                         icmp6_mtudisc_update(&ip6cp, 1);        /*XXX*/
1099                 }
1100
1101                 if (ip6_ctlprotox[nxt] != NULL)
1102                         ip6_ctlprotox[nxt](&ip6cp);
1103         }
1104         *mp = m;
1105         return (0);
1106
1107   freeit:
1108         m_freem(m);
1109         *mp = NULL;
1110         return (-1);
1111 }
1112
1113 void
1114 icmp6_mtudisc_update(struct ip6ctlparam *ip6cp, int validated)
1115 {
1116         struct in6_addr *dst = &ip6cp->ip6c_finaldst->sin6_addr;
1117         struct icmp6_hdr *icmp6 = ip6cp->ip6c_icmp6;
1118         struct mbuf *m = ip6cp->ip6c_m; /* will be necessary for scope issue */
1119         u_int mtu = ntohl(icmp6->icmp6_mtu);
1120         struct in_conninfo inc;
1121         uint32_t max_mtu;
1122
1123 #if 0
1124         /*
1125          * RFC2460 section 5, last paragraph.
1126          * even though minimum link MTU for IPv6 is IPV6_MMTU,
1127          * we may see ICMPv6 too big with mtu < IPV6_MMTU
1128          * due to packet translator in the middle.
1129          * see ip6_output() and ip6_getpmtu() "alwaysfrag" case for
1130          * special handling.
1131          */
1132         if (mtu < IPV6_MMTU)
1133                 return;
1134 #endif
1135
1136         /*
1137          * we reject ICMPv6 too big with abnormally small value.
1138          * XXX what is the good definition of "abnormally small"?
1139          */
1140         if (mtu < sizeof(struct ip6_hdr) + sizeof(struct ip6_frag) + 8)
1141                 return;
1142
1143         if (!validated)
1144                 return;
1145
1146         /*
1147          * In case the suggested mtu is less than IPV6_MMTU, we
1148          * only need to remember that it was for above mentioned
1149          * "alwaysfrag" case.
1150          * Try to be as close to the spec as possible.
1151          */
1152         if (mtu < IPV6_MMTU)
1153                 mtu = IPV6_MMTU - 8;
1154
1155         bzero(&inc, sizeof(inc));
1156         inc.inc_fibnum = M_GETFIB(m);
1157         inc.inc_flags |= INC_ISIPV6;
1158         inc.inc6_faddr = *dst;
1159         if (in6_setscope(&inc.inc6_faddr, m->m_pkthdr.rcvif, NULL))
1160                 return;
1161
1162         max_mtu = tcp_hc_getmtu(&inc);
1163         if (max_mtu == 0)
1164                 max_mtu = tcp_maxmtu6(&inc, NULL);
1165
1166         if (mtu < max_mtu) {
1167                 tcp_hc_updatemtu(&inc, mtu);
1168                 ICMP6STAT_INC(icp6s_pmtuchg);
1169         }
1170 }
1171
1172 /*
1173  * Process a Node Information Query packet, based on
1174  * draft-ietf-ipngwg-icmp-name-lookups-07.
1175  *
1176  * Spec incompatibilities:
1177  * - IPv6 Subject address handling
1178  * - IPv4 Subject address handling support missing
1179  * - Proxy reply (answer even if it's not for me)
1180  * - joins NI group address at in6_ifattach() time only, does not cope
1181  *   with hostname changes by sethostname(3)
1182  */
1183 static struct mbuf *
1184 ni6_input(struct mbuf *m, int off, struct prison *pr)
1185 {
1186         struct icmp6_nodeinfo *ni6, *nni6;
1187         struct mbuf *n = NULL;
1188         u_int16_t qtype;
1189         int subjlen;
1190         int replylen = sizeof(struct ip6_hdr) + sizeof(struct icmp6_nodeinfo);
1191         struct ni_reply_fqdn *fqdn;
1192         int addrs;              /* for NI_QTYPE_NODEADDR */
1193         struct ifnet *ifp = NULL; /* for NI_QTYPE_NODEADDR */
1194         struct in6_addr in6_subj; /* subject address */
1195         struct ip6_hdr *ip6;
1196         int oldfqdn = 0;        /* if 1, return pascal string (03 draft) */
1197         char *subj = NULL;
1198         struct in6_ifaddr *ia6 = NULL;
1199
1200         ip6 = mtod(m, struct ip6_hdr *);
1201         ni6 = (struct icmp6_nodeinfo *)(mtod(m, caddr_t) + off);
1202
1203         /*
1204          * Validate IPv6 source address.
1205          * The default configuration MUST be to refuse answering queries from
1206          * global-scope addresses according to RFC4602.
1207          * Notes:
1208          *  - it's not very clear what "refuse" means; this implementation
1209          *    simply drops it.
1210          *  - it's not very easy to identify global-scope (unicast) addresses
1211          *    since there are many prefixes for them.  It should be safer
1212          *    and in practice sufficient to check "all" but loopback and
1213          *    link-local (note that site-local unicast was deprecated and
1214          *    ULA is defined as global scope-wise)
1215          */
1216         if ((V_icmp6_nodeinfo & ICMP6_NODEINFO_GLOBALOK) == 0 &&
1217             !IN6_IS_ADDR_LOOPBACK(&ip6->ip6_src) &&
1218             !IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_src))
1219                 goto bad;
1220
1221         /*
1222          * Validate IPv6 destination address.
1223          *
1224          * The Responder must discard the Query without further processing
1225          * unless it is one of the Responder's unicast or anycast addresses, or
1226          * a link-local scope multicast address which the Responder has joined.
1227          * [RFC4602, Section 5.]
1228          */
1229         if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
1230                 if (!IN6_IS_ADDR_MC_LINKLOCAL(&ip6->ip6_dst))
1231                         goto bad;
1232                 /* else it's a link-local multicast, fine */
1233         } else {                /* unicast or anycast */
1234                 ia6 = in6ifa_ifwithaddr(&ip6->ip6_dst, 0 /* XXX */, false);
1235                 if (ia6 == NULL)
1236                         goto bad; /* XXX impossible */
1237
1238                 if ((ia6->ia6_flags & IN6_IFF_TEMPORARY) &&
1239                     !(V_icmp6_nodeinfo & ICMP6_NODEINFO_TMPADDROK)) {
1240                         nd6log((LOG_DEBUG, "ni6_input: ignore node info to "
1241                                 "a temporary address in %s:%d",
1242                                __FILE__, __LINE__));
1243                         goto bad;
1244                 }
1245         }
1246
1247         /* validate query Subject field. */
1248         qtype = ntohs(ni6->ni_qtype);
1249         subjlen = m->m_pkthdr.len - off - sizeof(struct icmp6_nodeinfo);
1250         switch (qtype) {
1251         case NI_QTYPE_NOOP:
1252         case NI_QTYPE_SUPTYPES:
1253                 /* 07 draft */
1254                 if (ni6->ni_code == ICMP6_NI_SUBJ_FQDN && subjlen == 0)
1255                         break;
1256                 /* FALLTHROUGH */
1257         case NI_QTYPE_FQDN:
1258         case NI_QTYPE_NODEADDR:
1259         case NI_QTYPE_IPV4ADDR:
1260                 switch (ni6->ni_code) {
1261                 case ICMP6_NI_SUBJ_IPV6:
1262 #if ICMP6_NI_SUBJ_IPV6 != 0
1263                 case 0:
1264 #endif
1265                         /*
1266                          * backward compatibility - try to accept 03 draft
1267                          * format, where no Subject is present.
1268                          */
1269                         if (qtype == NI_QTYPE_FQDN && ni6->ni_code == 0 &&
1270                             subjlen == 0) {
1271                                 oldfqdn++;
1272                                 break;
1273                         }
1274 #if ICMP6_NI_SUBJ_IPV6 != 0
1275                         if (ni6->ni_code != ICMP6_NI_SUBJ_IPV6)
1276                                 goto bad;
1277 #endif
1278
1279                         if (subjlen != sizeof(struct in6_addr))
1280                                 goto bad;
1281
1282                         /*
1283                          * Validate Subject address.
1284                          *
1285                          * Not sure what exactly "address belongs to the node"
1286                          * means in the spec, is it just unicast, or what?
1287                          *
1288                          * At this moment we consider Subject address as
1289                          * "belong to the node" if the Subject address equals
1290                          * to the IPv6 destination address; validation for
1291                          * IPv6 destination address should have done enough
1292                          * check for us.
1293                          *
1294                          * We do not do proxy at this moment.
1295                          */
1296                         m_copydata(m, off + sizeof(struct icmp6_nodeinfo),
1297                             subjlen, (caddr_t)&in6_subj);
1298                         if (in6_setscope(&in6_subj, m->m_pkthdr.rcvif, NULL))
1299                                 goto bad;
1300
1301                         subj = (char *)&in6_subj;
1302                         if (IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &in6_subj))
1303                                 break;
1304
1305                         /*
1306                          * XXX if we are to allow other cases, we should really
1307                          * be careful about scope here.
1308                          * basically, we should disallow queries toward IPv6
1309                          * destination X with subject Y,
1310                          * if scope(X) > scope(Y).
1311                          * if we allow scope(X) > scope(Y), it will result in
1312                          * information leakage across scope boundary.
1313                          */
1314                         goto bad;
1315
1316                 case ICMP6_NI_SUBJ_FQDN:
1317                         /*
1318                          * Validate Subject name with gethostname(3).
1319                          *
1320                          * The behavior may need some debate, since:
1321                          * - we are not sure if the node has FQDN as
1322                          *   hostname (returned by gethostname(3)).
1323                          * - the code does wildcard match for truncated names.
1324                          *   however, we are not sure if we want to perform
1325                          *   wildcard match, if gethostname(3) side has
1326                          *   truncated hostname.
1327                          */
1328                         mtx_lock(&pr->pr_mtx);
1329                         n = ni6_nametodns(pr->pr_hostname,
1330                             strlen(pr->pr_hostname), 0);
1331                         mtx_unlock(&pr->pr_mtx);
1332                         if (!n || n->m_next || n->m_len == 0)
1333                                 goto bad;
1334                         if (m->m_len < off + sizeof(struct icmp6_nodeinfo) +
1335                             subjlen) {
1336                                 m = m_pullup(m, off +
1337                                     sizeof(struct icmp6_nodeinfo) + subjlen);
1338                                 if (m == NULL) {
1339                                         IP6STAT_INC(ip6s_exthdrtoolong);
1340                                         goto bad;
1341                                 }
1342                         }
1343                         /* ip6 possibly invalid but not used after. */
1344                         ni6 = (struct icmp6_nodeinfo *)(mtod(m, caddr_t) + off);
1345                         subj = (char *)(mtod(m, caddr_t) + off +
1346                             sizeof(struct icmp6_nodeinfo));
1347                         if (!ni6_dnsmatch(subj, subjlen, mtod(n, const char *),
1348                             n->m_len)) {
1349                                 goto bad;
1350                         }
1351                         m_freem(n);
1352                         n = NULL;
1353                         break;
1354
1355                 case ICMP6_NI_SUBJ_IPV4:        /* XXX: to be implemented? */
1356                 default:
1357                         goto bad;
1358                 }
1359                 break;
1360         }
1361
1362         /* refuse based on configuration.  XXX ICMP6_NI_REFUSED? */
1363         switch (qtype) {
1364         case NI_QTYPE_FQDN:
1365                 if ((V_icmp6_nodeinfo & ICMP6_NODEINFO_FQDNOK) == 0)
1366                         goto bad;
1367                 break;
1368         case NI_QTYPE_NODEADDR:
1369         case NI_QTYPE_IPV4ADDR:
1370                 if ((V_icmp6_nodeinfo & ICMP6_NODEINFO_NODEADDROK) == 0)
1371                         goto bad;
1372                 break;
1373         }
1374
1375         /* guess reply length */
1376         switch (qtype) {
1377         case NI_QTYPE_NOOP:
1378                 break;          /* no reply data */
1379         case NI_QTYPE_SUPTYPES:
1380                 replylen += sizeof(u_int32_t);
1381                 break;
1382         case NI_QTYPE_FQDN:
1383                 /* XXX will append an mbuf */
1384                 replylen += offsetof(struct ni_reply_fqdn, ni_fqdn_namelen);
1385                 break;
1386         case NI_QTYPE_NODEADDR:
1387                 addrs = ni6_addrs(ni6, m, &ifp, (struct in6_addr *)subj);
1388                 if ((replylen += addrs * (sizeof(struct in6_addr) +
1389                     sizeof(u_int32_t))) > MCLBYTES)
1390                         replylen = MCLBYTES; /* XXX: will truncate pkt later */
1391                 break;
1392         case NI_QTYPE_IPV4ADDR:
1393                 /* unsupported - should respond with unknown Qtype? */
1394                 break;
1395         default:
1396                 /*
1397                  * XXX: We must return a reply with the ICMP6 code
1398                  * `unknown Qtype' in this case.  However we regard the case
1399                  * as an FQDN query for backward compatibility.
1400                  * Older versions set a random value to this field,
1401                  * so it rarely varies in the defined qtypes.
1402                  * But the mechanism is not reliable...
1403                  * maybe we should obsolete older versions.
1404                  */
1405                 qtype = NI_QTYPE_FQDN;
1406                 /* XXX will append an mbuf */
1407                 replylen += offsetof(struct ni_reply_fqdn, ni_fqdn_namelen);
1408                 oldfqdn++;
1409                 break;
1410         }
1411
1412         /* Allocate an mbuf to reply. */
1413         if (replylen > MCLBYTES) {
1414                 /*
1415                  * XXX: should we try to allocate more? But MCLBYTES
1416                  * is probably much larger than IPV6_MMTU...
1417                  */
1418                 goto bad;
1419         }
1420         if (replylen > MHLEN)
1421                 n = m_getcl(M_NOWAIT, m->m_type, M_PKTHDR);
1422         else
1423                 n = m_gethdr(M_NOWAIT, m->m_type);
1424         if (n == NULL) {
1425                 m_freem(m);
1426                 return (NULL);
1427         }
1428         m_move_pkthdr(n, m); /* just for recvif and FIB */
1429         n->m_pkthdr.len = n->m_len = replylen;
1430
1431         /* copy mbuf header and IPv6 + Node Information base headers */
1432         bcopy(mtod(m, caddr_t), mtod(n, caddr_t), sizeof(struct ip6_hdr));
1433         nni6 = (struct icmp6_nodeinfo *)(mtod(n, struct ip6_hdr *) + 1);
1434         bcopy((caddr_t)ni6, (caddr_t)nni6, sizeof(struct icmp6_nodeinfo));
1435
1436         /* qtype dependent procedure */
1437         switch (qtype) {
1438         case NI_QTYPE_NOOP:
1439                 nni6->ni_code = ICMP6_NI_SUCCESS;
1440                 nni6->ni_flags = 0;
1441                 break;
1442         case NI_QTYPE_SUPTYPES:
1443         {
1444                 u_int32_t v;
1445                 nni6->ni_code = ICMP6_NI_SUCCESS;
1446                 nni6->ni_flags = htons(0x0000); /* raw bitmap */
1447                 /* supports NOOP, SUPTYPES, FQDN, and NODEADDR */
1448                 v = (u_int32_t)htonl(0x0000000f);
1449                 bcopy(&v, nni6 + 1, sizeof(u_int32_t));
1450                 break;
1451         }
1452         case NI_QTYPE_FQDN:
1453                 nni6->ni_code = ICMP6_NI_SUCCESS;
1454                 fqdn = (struct ni_reply_fqdn *)(mtod(n, caddr_t) +
1455                     sizeof(struct ip6_hdr) + sizeof(struct icmp6_nodeinfo));
1456                 nni6->ni_flags = 0; /* XXX: meaningless TTL */
1457                 fqdn->ni_fqdn_ttl = 0;  /* ditto. */
1458                 /*
1459                  * XXX do we really have FQDN in hostname?
1460                  */
1461                 mtx_lock(&pr->pr_mtx);
1462                 n->m_next = ni6_nametodns(pr->pr_hostname,
1463                     strlen(pr->pr_hostname), oldfqdn);
1464                 mtx_unlock(&pr->pr_mtx);
1465                 if (n->m_next == NULL)
1466                         goto bad;
1467                 /* XXX we assume that n->m_next is not a chain */
1468                 if (n->m_next->m_next != NULL)
1469                         goto bad;
1470                 n->m_pkthdr.len += n->m_next->m_len;
1471                 break;
1472         case NI_QTYPE_NODEADDR:
1473         {
1474                 int lenlim, copied;
1475
1476                 nni6->ni_code = ICMP6_NI_SUCCESS;
1477                 n->m_pkthdr.len = n->m_len =
1478                     sizeof(struct ip6_hdr) + sizeof(struct icmp6_nodeinfo);
1479                 lenlim = M_TRAILINGSPACE(n);
1480                 copied = ni6_store_addrs(ni6, nni6, ifp, lenlim);
1481                 /* XXX: reset mbuf length */
1482                 n->m_pkthdr.len = n->m_len = sizeof(struct ip6_hdr) +
1483                     sizeof(struct icmp6_nodeinfo) + copied;
1484                 break;
1485         }
1486         default:
1487                 break;          /* XXX impossible! */
1488         }
1489
1490         nni6->ni_type = ICMP6_NI_REPLY;
1491         m_freem(m);
1492         return (n);
1493
1494   bad:
1495         m_freem(m);
1496         if (n)
1497                 m_freem(n);
1498         return (NULL);
1499 }
1500
1501 /*
1502  * make a mbuf with DNS-encoded string.  no compression support.
1503  *
1504  * XXX names with less than 2 dots (like "foo" or "foo.section") will be
1505  * treated as truncated name (two \0 at the end).  this is a wild guess.
1506  *
1507  * old - return pascal string if non-zero
1508  */
1509 static struct mbuf *
1510 ni6_nametodns(const char *name, int namelen, int old)
1511 {
1512         struct mbuf *m;
1513         char *cp, *ep;
1514         const char *p, *q;
1515         int i, len, nterm;
1516
1517         if (old)
1518                 len = namelen + 1;
1519         else
1520                 len = MCLBYTES;
1521
1522         /* Because MAXHOSTNAMELEN is usually 256, we use cluster mbuf. */
1523         if (len > MLEN)
1524                 m = m_getcl(M_NOWAIT, MT_DATA, 0);
1525         else
1526                 m = m_get(M_NOWAIT, MT_DATA);
1527         if (m == NULL)
1528                 goto fail;
1529
1530         if (old) {
1531                 m->m_len = len;
1532                 *mtod(m, char *) = namelen;
1533                 bcopy(name, mtod(m, char *) + 1, namelen);
1534                 return m;
1535         } else {
1536                 m->m_len = 0;
1537                 cp = mtod(m, char *);
1538                 ep = mtod(m, char *) + M_TRAILINGSPACE(m);
1539
1540                 /* if not certain about my name, return empty buffer */
1541                 if (namelen == 0)
1542                         return m;
1543
1544                 /*
1545                  * guess if it looks like shortened hostname, or FQDN.
1546                  * shortened hostname needs two trailing "\0".
1547                  */
1548                 i = 0;
1549                 for (p = name; p < name + namelen; p++) {
1550                         if (*p && *p == '.')
1551                                 i++;
1552                 }
1553                 if (i < 2)
1554                         nterm = 2;
1555                 else
1556                         nterm = 1;
1557
1558                 p = name;
1559                 while (cp < ep && p < name + namelen) {
1560                         i = 0;
1561                         for (q = p; q < name + namelen && *q && *q != '.'; q++)
1562                                 i++;
1563                         /* result does not fit into mbuf */
1564                         if (cp + i + 1 >= ep)
1565                                 goto fail;
1566                         /*
1567                          * DNS label length restriction, RFC1035 page 8.
1568                          * "i == 0" case is included here to avoid returning
1569                          * 0-length label on "foo..bar".
1570                          */
1571                         if (i <= 0 || i >= 64)
1572                                 goto fail;
1573                         *cp++ = i;
1574                         bcopy(p, cp, i);
1575                         cp += i;
1576                         p = q;
1577                         if (p < name + namelen && *p == '.')
1578                                 p++;
1579                 }
1580                 /* termination */
1581                 if (cp + nterm >= ep)
1582                         goto fail;
1583                 while (nterm-- > 0)
1584                         *cp++ = '\0';
1585                 m->m_len = cp - mtod(m, char *);
1586                 return m;
1587         }
1588
1589         panic("should not reach here");
1590         /* NOTREACHED */
1591
1592  fail:
1593         if (m)
1594                 m_freem(m);
1595         return NULL;
1596 }
1597
1598 /*
1599  * check if two DNS-encoded string matches.  takes care of truncated
1600  * form (with \0\0 at the end).  no compression support.
1601  * XXX upper/lowercase match (see RFC2065)
1602  */
1603 static int
1604 ni6_dnsmatch(const char *a, int alen, const char *b, int blen)
1605 {
1606         const char *a0, *b0;
1607         int l;
1608
1609         /* simplest case - need validation? */
1610         if (alen == blen && bcmp(a, b, alen) == 0)
1611                 return 1;
1612
1613         a0 = a;
1614         b0 = b;
1615
1616         /* termination is mandatory */
1617         if (alen < 2 || blen < 2)
1618                 return 0;
1619         if (a0[alen - 1] != '\0' || b0[blen - 1] != '\0')
1620                 return 0;
1621         alen--;
1622         blen--;
1623
1624         while (a - a0 < alen && b - b0 < blen) {
1625                 if (a - a0 + 1 > alen || b - b0 + 1 > blen)
1626                         return 0;
1627
1628                 if ((signed char)a[0] < 0 || (signed char)b[0] < 0)
1629                         return 0;
1630                 /* we don't support compression yet */
1631                 if (a[0] >= 64 || b[0] >= 64)
1632                         return 0;
1633
1634                 /* truncated case */
1635                 if (a[0] == 0 && a - a0 == alen - 1)
1636                         return 1;
1637                 if (b[0] == 0 && b - b0 == blen - 1)
1638                         return 1;
1639                 if (a[0] == 0 || b[0] == 0)
1640                         return 0;
1641
1642                 if (a[0] != b[0])
1643                         return 0;
1644                 l = a[0];
1645                 if (a - a0 + 1 + l > alen || b - b0 + 1 + l > blen)
1646                         return 0;
1647                 if (bcmp(a + 1, b + 1, l) != 0)
1648                         return 0;
1649
1650                 a += 1 + l;
1651                 b += 1 + l;
1652         }
1653
1654         if (a - a0 == alen && b - b0 == blen)
1655                 return 1;
1656         else
1657                 return 0;
1658 }
1659
1660 /*
1661  * calculate the number of addresses to be returned in the node info reply.
1662  */
1663 static int
1664 ni6_addrs(struct icmp6_nodeinfo *ni6, struct mbuf *m, struct ifnet **ifpp,
1665     struct in6_addr *subj)
1666 {
1667         struct ifnet *ifp;
1668         struct in6_ifaddr *ifa6;
1669         struct ifaddr *ifa;
1670         int addrs = 0, addrsofif, iffound = 0;
1671         int niflags = ni6->ni_flags;
1672
1673         NET_EPOCH_ASSERT();
1674
1675         if ((niflags & NI_NODEADDR_FLAG_ALL) == 0) {
1676                 switch (ni6->ni_code) {
1677                 case ICMP6_NI_SUBJ_IPV6:
1678                         if (subj == NULL) /* must be impossible... */
1679                                 return (0);
1680                         break;
1681                 default:
1682                         /*
1683                          * XXX: we only support IPv6 subject address for
1684                          * this Qtype.
1685                          */
1686                         return (0);
1687                 }
1688         }
1689
1690         CK_STAILQ_FOREACH(ifp, &V_ifnet, if_link) {
1691                 addrsofif = 0;
1692                 CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
1693                         if (ifa->ifa_addr->sa_family != AF_INET6)
1694                                 continue;
1695                         ifa6 = (struct in6_ifaddr *)ifa;
1696
1697                         if ((niflags & NI_NODEADDR_FLAG_ALL) == 0 &&
1698                             IN6_ARE_ADDR_EQUAL(subj, &ifa6->ia_addr.sin6_addr))
1699                                 iffound = 1;
1700
1701                         /*
1702                          * IPv4-mapped addresses can only be returned by a
1703                          * Node Information proxy, since they represent
1704                          * addresses of IPv4-only nodes, which perforce do
1705                          * not implement this protocol.
1706                          * [icmp-name-lookups-07, Section 5.4]
1707                          * So we don't support NI_NODEADDR_FLAG_COMPAT in
1708                          * this function at this moment.
1709                          */
1710
1711                         /* What do we have to do about ::1? */
1712                         switch (in6_addrscope(&ifa6->ia_addr.sin6_addr)) {
1713                         case IPV6_ADDR_SCOPE_LINKLOCAL:
1714                                 if ((niflags & NI_NODEADDR_FLAG_LINKLOCAL) == 0)
1715                                         continue;
1716                                 break;
1717                         case IPV6_ADDR_SCOPE_SITELOCAL:
1718                                 if ((niflags & NI_NODEADDR_FLAG_SITELOCAL) == 0)
1719                                         continue;
1720                                 break;
1721                         case IPV6_ADDR_SCOPE_GLOBAL:
1722                                 if ((niflags & NI_NODEADDR_FLAG_GLOBAL) == 0)
1723                                         continue;
1724                                 break;
1725                         default:
1726                                 continue;
1727                         }
1728
1729                         /*
1730                          * check if anycast is okay.
1731                          * XXX: just experimental.  not in the spec.
1732                          */
1733                         if ((ifa6->ia6_flags & IN6_IFF_ANYCAST) != 0 &&
1734                             (niflags & NI_NODEADDR_FLAG_ANYCAST) == 0)
1735                                 continue; /* we need only unicast addresses */
1736                         if ((ifa6->ia6_flags & IN6_IFF_TEMPORARY) != 0 &&
1737                             (V_icmp6_nodeinfo & ICMP6_NODEINFO_TMPADDROK) == 0) {
1738                                 continue;
1739                         }
1740                         addrsofif++; /* count the address */
1741                 }
1742                 if (iffound) {
1743                         *ifpp = ifp;
1744                         return (addrsofif);
1745                 }
1746
1747                 addrs += addrsofif;
1748         }
1749
1750         return (addrs);
1751 }
1752
1753 static int
1754 ni6_store_addrs(struct icmp6_nodeinfo *ni6, struct icmp6_nodeinfo *nni6,
1755     struct ifnet *ifp0, int resid)
1756 {
1757         struct ifnet *ifp;
1758         struct in6_ifaddr *ifa6;
1759         struct ifaddr *ifa;
1760         struct ifnet *ifp_dep = NULL;
1761         int copied = 0, allow_deprecated = 0;
1762         u_char *cp = (u_char *)(nni6 + 1);
1763         int niflags = ni6->ni_flags;
1764         u_int32_t ltime;
1765
1766         NET_EPOCH_ASSERT();
1767
1768         if (ifp0 == NULL && !(niflags & NI_NODEADDR_FLAG_ALL))
1769                 return (0);     /* needless to copy */
1770
1771         ifp = ifp0 ? ifp0 : CK_STAILQ_FIRST(&V_ifnet);
1772   again:
1773
1774         for (; ifp; ifp = CK_STAILQ_NEXT(ifp, if_link)) {
1775                 CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
1776                         if (ifa->ifa_addr->sa_family != AF_INET6)
1777                                 continue;
1778                         ifa6 = (struct in6_ifaddr *)ifa;
1779
1780                         if ((ifa6->ia6_flags & IN6_IFF_DEPRECATED) != 0 &&
1781                             allow_deprecated == 0) {
1782                                 /*
1783                                  * prefererred address should be put before
1784                                  * deprecated addresses.
1785                                  */
1786
1787                                 /* record the interface for later search */
1788                                 if (ifp_dep == NULL)
1789                                         ifp_dep = ifp;
1790
1791                                 continue;
1792                         } else if ((ifa6->ia6_flags & IN6_IFF_DEPRECATED) == 0 &&
1793                             allow_deprecated != 0)
1794                                 continue; /* we now collect deprecated addrs */
1795
1796                         /* What do we have to do about ::1? */
1797                         switch (in6_addrscope(&ifa6->ia_addr.sin6_addr)) {
1798                         case IPV6_ADDR_SCOPE_LINKLOCAL:
1799                                 if ((niflags & NI_NODEADDR_FLAG_LINKLOCAL) == 0)
1800                                         continue;
1801                                 break;
1802                         case IPV6_ADDR_SCOPE_SITELOCAL:
1803                                 if ((niflags & NI_NODEADDR_FLAG_SITELOCAL) == 0)
1804                                         continue;
1805                                 break;
1806                         case IPV6_ADDR_SCOPE_GLOBAL:
1807                                 if ((niflags & NI_NODEADDR_FLAG_GLOBAL) == 0)
1808                                         continue;
1809                                 break;
1810                         default:
1811                                 continue;
1812                         }
1813
1814                         /*
1815                          * check if anycast is okay.
1816                          * XXX: just experimental.  not in the spec.
1817                          */
1818                         if ((ifa6->ia6_flags & IN6_IFF_ANYCAST) != 0 &&
1819                             (niflags & NI_NODEADDR_FLAG_ANYCAST) == 0)
1820                                 continue;
1821                         if ((ifa6->ia6_flags & IN6_IFF_TEMPORARY) != 0 &&
1822                             (V_icmp6_nodeinfo & ICMP6_NODEINFO_TMPADDROK) == 0) {
1823                                 continue;
1824                         }
1825
1826                         /* now we can copy the address */
1827                         if (resid < sizeof(struct in6_addr) +
1828                             sizeof(u_int32_t)) {
1829                                 /*
1830                                  * We give up much more copy.
1831                                  * Set the truncate flag and return.
1832                                  */
1833                                 nni6->ni_flags |= NI_NODEADDR_FLAG_TRUNCATE;
1834                                 return (copied);
1835                         }
1836
1837                         /*
1838                          * Set the TTL of the address.
1839                          * The TTL value should be one of the following
1840                          * according to the specification:
1841                          *
1842                          * 1. The remaining lifetime of a DHCP lease on the
1843                          *    address, or
1844                          * 2. The remaining Valid Lifetime of a prefix from
1845                          *    which the address was derived through Stateless
1846                          *    Autoconfiguration.
1847                          *
1848                          * Note that we currently do not support stateful
1849                          * address configuration by DHCPv6, so the former
1850                          * case can't happen.
1851                          */
1852                         if (ifa6->ia6_lifetime.ia6t_expire == 0)
1853                                 ltime = ND6_INFINITE_LIFETIME;
1854                         else {
1855                                 if (ifa6->ia6_lifetime.ia6t_expire >
1856                                     time_uptime)
1857                                         ltime = htonl(ifa6->ia6_lifetime.ia6t_expire - time_uptime);
1858                                 else
1859                                         ltime = 0;
1860                         }
1861
1862                         bcopy(&ltime, cp, sizeof(u_int32_t));
1863                         cp += sizeof(u_int32_t);
1864
1865                         /* copy the address itself */
1866                         bcopy(&ifa6->ia_addr.sin6_addr, cp,
1867                             sizeof(struct in6_addr));
1868                         in6_clearscope((struct in6_addr *)cp); /* XXX */
1869                         cp += sizeof(struct in6_addr);
1870
1871                         resid -= (sizeof(struct in6_addr) + sizeof(u_int32_t));
1872                         copied += (sizeof(struct in6_addr) + sizeof(u_int32_t));
1873                 }
1874                 if (ifp0)       /* we need search only on the specified IF */
1875                         break;
1876         }
1877
1878         if (allow_deprecated == 0 && ifp_dep != NULL) {
1879                 ifp = ifp_dep;
1880                 allow_deprecated = 1;
1881
1882                 goto again;
1883         }
1884
1885         return (copied);
1886 }
1887
1888 static bool
1889 icmp6_rip6_match(const struct inpcb *inp, void *v)
1890 {
1891         struct ip6_hdr *ip6 = v;
1892
1893         if ((inp->inp_vflag & INP_IPV6) == 0)
1894                 return (false);
1895         if (inp->inp_ip_p != IPPROTO_ICMPV6)
1896                 return (false);
1897         if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr) &&
1898            !IN6_ARE_ADDR_EQUAL(&inp->in6p_laddr, &ip6->ip6_dst))
1899                 return (false);
1900         if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr) &&
1901            !IN6_ARE_ADDR_EQUAL(&inp->in6p_faddr, &ip6->ip6_src))
1902                 return (false);
1903         return (true);
1904 }
1905
1906 /*
1907  * XXX almost dup'ed code with rip6_input.
1908  */
1909 static int
1910 icmp6_rip6_input(struct mbuf **mp, int off)
1911 {
1912         struct mbuf *n, *m = *mp;
1913         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
1914         struct inpcb_iterator inpi = INP_ITERATOR(&V_ripcbinfo,
1915             INPLOOKUP_RLOCKPCB, icmp6_rip6_match, ip6);
1916         struct inpcb *inp;
1917         struct sockaddr_in6 fromsa;
1918         struct icmp6_hdr *icmp6;
1919         struct mbuf *opts = NULL;
1920         int delivered = 0;
1921
1922         /* This is assumed to be safe; icmp6_input() does a pullup. */
1923         icmp6 = (struct icmp6_hdr *)((caddr_t)ip6 + off);
1924
1925         /*
1926          * XXX: the address may have embedded scope zone ID, which should be
1927          * hidden from applications.
1928          */
1929         bzero(&fromsa, sizeof(fromsa));
1930         fromsa.sin6_family = AF_INET6;
1931         fromsa.sin6_len = sizeof(struct sockaddr_in6);
1932         fromsa.sin6_addr = ip6->ip6_src;
1933         if (sa6_recoverscope(&fromsa)) {
1934                 m_freem(m);
1935                 *mp = NULL;
1936                 return (IPPROTO_DONE);
1937         }
1938
1939         while ((inp = inp_next(&inpi)) != NULL) {
1940                 if (ICMP6_FILTER_WILLBLOCK(icmp6->icmp6_type,
1941                     inp->in6p_icmp6filt))
1942                         continue;
1943                 /*
1944                  * Recent network drivers tend to allocate a single
1945                  * mbuf cluster, rather than to make a couple of
1946                  * mbufs without clusters.  Also, since the IPv6 code
1947                  * path tries to avoid m_pullup(), it is highly
1948                  * probable that we still have an mbuf cluster here
1949                  * even though the necessary length can be stored in an
1950                  * mbuf's internal buffer.
1951                  * Meanwhile, the default size of the receive socket
1952                  * buffer for raw sockets is not so large.  This means
1953                  * the possibility of packet loss is relatively higher
1954                  * than before.  To avoid this scenario, we copy the
1955                  * received data to a separate mbuf that does not use
1956                  * a cluster, if possible.
1957                  * XXX: it is better to copy the data after stripping
1958                  * intermediate headers.
1959                  */
1960                 if ((m->m_flags & M_EXT) && m->m_next == NULL &&
1961                     m->m_len <= MHLEN) {
1962                         n = m_get(M_NOWAIT, m->m_type);
1963                         if (n != NULL) {
1964                                 if (m_dup_pkthdr(n, m, M_NOWAIT)) {
1965                                         bcopy(m->m_data, n->m_data, m->m_len);
1966                                         n->m_len = m->m_len;
1967                                 } else {
1968                                         m_free(n);
1969                                         n = NULL;
1970                                 }
1971                         }
1972                 } else
1973                         n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
1974                 if (n == NULL)
1975                         continue;
1976                 if (inp->inp_flags & INP_CONTROLOPTS)
1977                         ip6_savecontrol(inp, n, &opts);
1978                 /* strip intermediate headers */
1979                 m_adj(n, off);
1980                 SOCKBUF_LOCK(&inp->inp_socket->so_rcv);
1981                 if (sbappendaddr_locked(&inp->inp_socket->so_rcv,
1982                     (struct sockaddr *)&fromsa, n, opts) == 0) {
1983                         soroverflow_locked(inp->inp_socket);
1984                         m_freem(n);
1985                         if (opts)
1986                                 m_freem(opts);
1987                 } else {
1988                         sorwakeup_locked(inp->inp_socket);
1989                         delivered++;
1990                 }
1991                 opts = NULL;
1992         }
1993         m_freem(m);
1994         *mp = NULL;
1995         if (delivered == 0)
1996                 IP6STAT_DEC(ip6s_delivered);
1997         return (IPPROTO_DONE);
1998 }
1999
2000 /*
2001  * Reflect the ip6 packet back to the source.
2002  * OFF points to the icmp6 header, counted from the top of the mbuf.
2003  */
2004 static void
2005 icmp6_reflect(struct mbuf *m, size_t off)
2006 {
2007         struct in6_addr src6, *srcp;
2008         struct ip6_hdr *ip6;
2009         struct icmp6_hdr *icmp6;
2010         struct in6_ifaddr *ia = NULL;
2011         struct ifnet *outif = NULL;
2012         int plen;
2013         int type, code, hlim;
2014
2015         /* too short to reflect */
2016         if (off < sizeof(struct ip6_hdr)) {
2017                 nd6log((LOG_DEBUG,
2018                     "sanity fail: off=%lx, sizeof(ip6)=%lx in %s:%d\n",
2019                     (u_long)off, (u_long)sizeof(struct ip6_hdr),
2020                     __FILE__, __LINE__));
2021                 goto bad;
2022         }
2023
2024         /*
2025          * If there are extra headers between IPv6 and ICMPv6, strip
2026          * off that header first.
2027          */
2028 #ifdef DIAGNOSTIC
2029         if (sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr) > MHLEN)
2030                 panic("assumption failed in icmp6_reflect");
2031 #endif
2032         if (off > sizeof(struct ip6_hdr)) {
2033                 size_t l;
2034                 struct ip6_hdr nip6;
2035
2036                 l = off - sizeof(struct ip6_hdr);
2037                 m_copydata(m, 0, sizeof(nip6), (caddr_t)&nip6);
2038                 m_adj(m, l);
2039                 l = sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr);
2040                 if (m->m_len < l) {
2041                         if ((m = m_pullup(m, l)) == NULL)
2042                                 return;
2043                 }
2044                 bcopy((caddr_t)&nip6, mtod(m, caddr_t), sizeof(nip6));
2045         } else /* off == sizeof(struct ip6_hdr) */ {
2046                 size_t l;
2047                 l = sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr);
2048                 if (m->m_len < l) {
2049                         if ((m = m_pullup(m, l)) == NULL)
2050                                 return;
2051                 }
2052         }
2053         plen = m->m_pkthdr.len - sizeof(struct ip6_hdr);
2054         ip6 = mtod(m, struct ip6_hdr *);
2055         ip6->ip6_nxt = IPPROTO_ICMPV6;
2056         icmp6 = (struct icmp6_hdr *)(ip6 + 1);
2057         type = icmp6->icmp6_type; /* keep type for statistics */
2058         code = icmp6->icmp6_code; /* ditto. */
2059         hlim = 0;
2060         srcp = NULL;
2061
2062         /*
2063          * If the incoming packet was addressed directly to us (i.e. unicast),
2064          * use dst as the src for the reply.
2065          * The IN6_IFF_NOTREADY case should be VERY rare, but is possible
2066          * (for example) when we encounter an error while forwarding procedure
2067          * destined to a duplicated address of ours.
2068          */
2069         if (!IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
2070                 ia = in6ifa_ifwithaddr(&ip6->ip6_dst, 0 /* XXX */, false);
2071                 if (ia != NULL && !(ia->ia6_flags &
2072                     (IN6_IFF_ANYCAST|IN6_IFF_NOTREADY))) {
2073                         src6 = ia->ia_addr.sin6_addr;
2074                         srcp = &src6;
2075
2076                         if (m->m_pkthdr.rcvif != NULL) {
2077                                 /* XXX: This may not be the outgoing interface */
2078                                 hlim = ND_IFINFO(m->m_pkthdr.rcvif)->chlim;
2079                         } else
2080                                 hlim = V_ip6_defhlim;
2081                 }
2082         }
2083
2084         if (srcp == NULL) {
2085                 int error;
2086                 struct in6_addr dst6;
2087                 uint32_t scopeid;
2088
2089                 /*
2090                  * This case matches to multicasts, our anycast, or unicasts
2091                  * that we do not own.  Select a source address based on the
2092                  * source address of the erroneous packet.
2093                  */
2094                 in6_splitscope(&ip6->ip6_src, &dst6, &scopeid);
2095                 error = in6_selectsrc_addr(M_GETFIB(m), &dst6,
2096                     scopeid, NULL, &src6, &hlim);
2097
2098                 if (error) {
2099                         char ip6buf[INET6_ADDRSTRLEN];
2100                         nd6log((LOG_DEBUG,
2101                             "icmp6_reflect: source can't be determined: "
2102                             "dst=%s, error=%d\n",
2103                             ip6_sprintf(ip6buf, &ip6->ip6_dst), error));
2104                         goto bad;
2105                 }
2106                 srcp = &src6;
2107         }
2108         /*
2109          * ip6_input() drops a packet if its src is multicast.
2110          * So, the src is never multicast.
2111          */
2112         ip6->ip6_dst = ip6->ip6_src;
2113         ip6->ip6_src = *srcp;
2114         ip6->ip6_flow = 0;
2115         ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
2116         ip6->ip6_vfc |= IPV6_VERSION;
2117         ip6->ip6_nxt = IPPROTO_ICMPV6;
2118         ip6->ip6_hlim = hlim;
2119
2120         icmp6->icmp6_cksum = 0;
2121         icmp6->icmp6_cksum = in6_cksum(m, IPPROTO_ICMPV6,
2122             sizeof(struct ip6_hdr), plen);
2123
2124         /*
2125          * XXX option handling
2126          */
2127
2128         m->m_flags &= ~(M_BCAST|M_MCAST);
2129         m->m_pkthdr.rcvif = NULL;
2130         ip6_output(m, NULL, NULL, 0, NULL, &outif, NULL);
2131         if (outif)
2132                 icmp6_ifoutstat_inc(outif, type, code);
2133
2134         return;
2135
2136  bad:
2137         m_freem(m);
2138         return;
2139 }
2140
2141 static const char *
2142 icmp6_redirect_diag(struct in6_addr *src6, struct in6_addr *dst6,
2143     struct in6_addr *tgt6)
2144 {
2145         static char buf[1024];
2146         char ip6bufs[INET6_ADDRSTRLEN];
2147         char ip6bufd[INET6_ADDRSTRLEN];
2148         char ip6buft[INET6_ADDRSTRLEN];
2149         snprintf(buf, sizeof(buf), "(src=%s dst=%s tgt=%s)",
2150             ip6_sprintf(ip6bufs, src6), ip6_sprintf(ip6bufd, dst6),
2151             ip6_sprintf(ip6buft, tgt6));
2152         return buf;
2153 }
2154
2155 void
2156 icmp6_redirect_input(struct mbuf *m, int off)
2157 {
2158         struct ifnet *ifp;
2159         struct ip6_hdr *ip6;
2160         struct nd_redirect *nd_rd;
2161         struct in6_addr src6, redtgt6, reddst6;
2162         union nd_opts ndopts;
2163         char ip6buf[INET6_ADDRSTRLEN];
2164         char *lladdr;
2165         int icmp6len, is_onlink, is_router, lladdrlen;
2166
2167         M_ASSERTPKTHDR(m);
2168         KASSERT(m->m_pkthdr.rcvif != NULL, ("%s: no rcvif", __func__));
2169
2170         /* XXX if we are router, we don't update route by icmp6 redirect */
2171         if (V_ip6_forwarding)
2172                 goto freeit;
2173         if (!V_icmp6_rediraccept)
2174                 goto freeit;
2175
2176         /* RFC 6980: Nodes MUST silently ignore fragments */
2177         if(m->m_flags & M_FRAGMENTED)
2178                 goto freeit;
2179
2180         ip6 = mtod(m, struct ip6_hdr *);
2181         icmp6len = ntohs(ip6->ip6_plen);
2182         if (m->m_len < off + icmp6len) {
2183                 m = m_pullup(m, off + icmp6len);
2184                 if (m == NULL) {
2185                         IP6STAT_INC(ip6s_exthdrtoolong);
2186                         return;
2187                 }
2188         }
2189         ip6 = mtod(m, struct ip6_hdr *);
2190         nd_rd = (struct nd_redirect *)((caddr_t)ip6 + off);
2191
2192         ifp = m->m_pkthdr.rcvif;
2193         redtgt6 = nd_rd->nd_rd_target;
2194         reddst6 = nd_rd->nd_rd_dst;
2195
2196         if (in6_setscope(&redtgt6, ifp, NULL) ||
2197             in6_setscope(&reddst6, ifp, NULL)) {
2198                 goto freeit;
2199         }
2200
2201         /* validation */
2202         src6 = ip6->ip6_src;
2203         if (!IN6_IS_ADDR_LINKLOCAL(&src6)) {
2204                 nd6log((LOG_ERR,
2205                     "ICMP6 redirect sent from %s rejected; "
2206                     "must be from linklocal\n",
2207                     ip6_sprintf(ip6buf, &src6)));
2208                 goto bad;
2209         }
2210         if (__predict_false(ip6->ip6_hlim != 255)) {
2211                 ICMP6STAT_INC(icp6s_invlhlim);
2212                 nd6log((LOG_ERR,
2213                     "ICMP6 redirect sent from %s rejected; "
2214                     "hlim=%d (must be 255)\n",
2215                     ip6_sprintf(ip6buf, &src6), ip6->ip6_hlim));
2216                 goto bad;
2217         }
2218     {
2219         /* ip6->ip6_src must be equal to gw for icmp6->icmp6_reddst */
2220         struct nhop_object *nh;
2221         struct in6_addr kdst;
2222         uint32_t scopeid;
2223
2224         in6_splitscope(&reddst6, &kdst, &scopeid);
2225         NET_EPOCH_ASSERT();
2226         nh = fib6_lookup(ifp->if_fib, &kdst, scopeid, 0, 0);
2227         if (nh != NULL) {
2228                 struct in6_addr nh_addr;
2229                 nh_addr = ifatoia6(nh->nh_ifa)->ia_addr.sin6_addr;
2230                 if ((nh->nh_flags & NHF_GATEWAY) == 0) {
2231                         nd6log((LOG_ERR,
2232                             "ICMP6 redirect rejected; no route "
2233                             "with inet6 gateway found for redirect dst: %s\n",
2234                             icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2235                         goto bad;
2236                 }
2237
2238                 /*
2239                  * Embed scope zone id into next hop address.
2240                  */
2241                 nh_addr = nh->gw6_sa.sin6_addr;
2242
2243                 if (IN6_ARE_ADDR_EQUAL(&src6, &nh_addr) == 0) {
2244                         nd6log((LOG_ERR,
2245                             "ICMP6 redirect rejected; "
2246                             "not equal to gw-for-src=%s (must be same): "
2247                             "%s\n",
2248                             ip6_sprintf(ip6buf, &nh_addr),
2249                             icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2250                         goto bad;
2251                 }
2252         } else {
2253                 nd6log((LOG_ERR,
2254                     "ICMP6 redirect rejected; "
2255                     "no route found for redirect dst: %s\n",
2256                     icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2257                 goto bad;
2258         }
2259     }
2260         if (IN6_IS_ADDR_MULTICAST(&reddst6)) {
2261                 nd6log((LOG_ERR,
2262                     "ICMP6 redirect rejected; "
2263                     "redirect dst must be unicast: %s\n",
2264                     icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2265                 goto bad;
2266         }
2267
2268         is_router = is_onlink = 0;
2269         if (IN6_IS_ADDR_LINKLOCAL(&redtgt6))
2270                 is_router = 1;  /* router case */
2271         if (bcmp(&redtgt6, &reddst6, sizeof(redtgt6)) == 0)
2272                 is_onlink = 1;  /* on-link destination case */
2273         if (!is_router && !is_onlink) {
2274                 nd6log((LOG_ERR,
2275                     "ICMP6 redirect rejected; "
2276                     "neither router case nor onlink case: %s\n",
2277                     icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2278                 goto bad;
2279         }
2280
2281         icmp6len -= sizeof(*nd_rd);
2282         nd6_option_init(nd_rd + 1, icmp6len, &ndopts);
2283         if (nd6_options(&ndopts) < 0) {
2284                 nd6log((LOG_INFO, "%s: invalid ND option, rejected: %s\n",
2285                     __func__, icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2286                 /* nd6_options have incremented stats */
2287                 goto freeit;
2288         }
2289
2290         lladdr = NULL;
2291         lladdrlen = 0;
2292         if (ndopts.nd_opts_tgt_lladdr) {
2293                 lladdr = (char *)(ndopts.nd_opts_tgt_lladdr + 1);
2294                 lladdrlen = ndopts.nd_opts_tgt_lladdr->nd_opt_len << 3;
2295         }
2296
2297         if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
2298                 nd6log((LOG_INFO, "%s: lladdrlen mismatch for %s "
2299                     "(if %d, icmp6 packet %d): %s\n",
2300                     __func__, ip6_sprintf(ip6buf, &redtgt6),
2301                     ifp->if_addrlen, lladdrlen - 2,
2302                     icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2303                 goto bad;
2304         }
2305
2306         /* Validation passed. */
2307
2308         /* RFC 2461 8.3 */
2309         nd6_cache_lladdr(ifp, &redtgt6, lladdr, lladdrlen, ND_REDIRECT,
2310             is_onlink ? ND_REDIRECT_ONLINK : ND_REDIRECT_ROUTER);
2311
2312         /*
2313          * Install a gateway route in the better-router case or an interface
2314          * route in the on-link-destination case.
2315          */
2316         {
2317                 struct sockaddr_in6 sdst;
2318                 struct sockaddr_in6 sgw;
2319                 struct sockaddr_in6 ssrc;
2320                 struct sockaddr *gw;
2321                 int rt_flags;
2322                 u_int fibnum;
2323
2324                 bzero(&sdst, sizeof(sdst));
2325                 bzero(&ssrc, sizeof(ssrc));
2326                 sdst.sin6_family = ssrc.sin6_family = AF_INET6;
2327                 sdst.sin6_len = ssrc.sin6_len = sizeof(struct sockaddr_in6);
2328                 bcopy(&reddst6, &sdst.sin6_addr, sizeof(struct in6_addr));
2329                 bcopy(&src6, &ssrc.sin6_addr, sizeof(struct in6_addr));
2330                 rt_flags = 0;
2331                 if (is_router) {
2332                         bzero(&sgw, sizeof(sgw));
2333                         sgw.sin6_family = AF_INET6;
2334                         sgw.sin6_len = sizeof(struct sockaddr_in6);
2335                         bcopy(&redtgt6, &sgw.sin6_addr,
2336                                 sizeof(struct in6_addr));
2337                         gw = (struct sockaddr *)&sgw;
2338                         rt_flags |= RTF_GATEWAY;
2339                 } else
2340                         gw = ifp->if_addr->ifa_addr;
2341                 for (fibnum = 0; fibnum < rt_numfibs; fibnum++)
2342                         rib_add_redirect(fibnum, (struct sockaddr *)&sdst, gw,
2343                             (struct sockaddr *)&ssrc, ifp, rt_flags,
2344                             V_icmp6_redirtimeout);
2345         }
2346
2347  freeit:
2348         m_freem(m);
2349         return;
2350
2351  bad:
2352         ICMP6STAT_INC(icp6s_badredirect);
2353         m_freem(m);
2354 }
2355
2356 void
2357 icmp6_redirect_output(struct mbuf *m0, struct nhop_object *nh)
2358 {
2359         struct ifnet *ifp;      /* my outgoing interface */
2360         struct in6_addr *ifp_ll6;
2361         struct in6_addr *router_ll6;
2362         struct ip6_hdr *sip6;   /* m0 as struct ip6_hdr */
2363         struct mbuf *m = NULL;  /* newly allocated one */
2364         struct m_tag *mtag;
2365         struct ip6_hdr *ip6;    /* m as struct ip6_hdr */
2366         struct nd_redirect *nd_rd;
2367         struct llentry *ln = NULL;
2368         size_t maxlen;
2369         u_char *p;
2370         struct ifnet *outif = NULL;
2371         struct sockaddr_in6 src_sa;
2372
2373         icmp6_errcount(ND_REDIRECT, 0);
2374
2375         /* if we are not router, we don't send icmp6 redirect */
2376         if (!V_ip6_forwarding)
2377                 goto fail;
2378
2379         /* sanity check */
2380         if (!m0 || !nh || !(NH_IS_VALID(nh)) || !(ifp = nh->nh_ifp))
2381                 goto fail;
2382
2383         /*
2384          * Address check:
2385          *  the source address must identify a neighbor, and
2386          *  the destination address must not be a multicast address
2387          *  [RFC 2461, sec 8.2]
2388          */
2389         sip6 = mtod(m0, struct ip6_hdr *);
2390         bzero(&src_sa, sizeof(src_sa));
2391         src_sa.sin6_family = AF_INET6;
2392         src_sa.sin6_len = sizeof(src_sa);
2393         src_sa.sin6_addr = sip6->ip6_src;
2394         if (nd6_is_addr_neighbor(&src_sa, ifp) == 0)
2395                 goto fail;
2396         if (IN6_IS_ADDR_MULTICAST(&sip6->ip6_dst))
2397                 goto fail;      /* what should we do here? */
2398
2399         /* rate limit */
2400         if (icmp6_ratelimit(&sip6->ip6_src, ND_REDIRECT, 0))
2401                 goto fail;
2402
2403         /*
2404          * Since we are going to append up to 1280 bytes (= IPV6_MMTU),
2405          * we almost always ask for an mbuf cluster for simplicity.
2406          * (MHLEN < IPV6_MMTU is almost always true)
2407          */
2408 #if IPV6_MMTU >= MCLBYTES
2409 # error assumption failed about IPV6_MMTU and MCLBYTES
2410 #endif
2411         m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
2412         if (m == NULL)
2413                 goto fail;
2414         M_SETFIB(m, M_GETFIB(m0));
2415         maxlen = M_TRAILINGSPACE(m);
2416         maxlen = min(IPV6_MMTU, maxlen);
2417         /* just for safety */
2418         if (maxlen < sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr) +
2419             ((sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7)) {
2420                 goto fail;
2421         }
2422
2423         {
2424                 /* get ip6 linklocal address for ifp(my outgoing interface). */
2425                 struct in6_ifaddr *ia;
2426                 if ((ia = in6ifa_ifpforlinklocal(ifp,
2427                                                  IN6_IFF_NOTREADY|
2428                                                  IN6_IFF_ANYCAST)) == NULL)
2429                         goto fail;
2430                 ifp_ll6 = &ia->ia_addr.sin6_addr;
2431                 /* XXXRW: reference released prematurely. */
2432                 ifa_free(&ia->ia_ifa);
2433         }
2434
2435         /* get ip6 linklocal address for the router. */
2436         if (nh->nh_flags & NHF_GATEWAY) {
2437                 struct sockaddr_in6 *sin6;
2438                 sin6 = &nh->gw6_sa;
2439                 router_ll6 = &sin6->sin6_addr;
2440                 if (!IN6_IS_ADDR_LINKLOCAL(router_ll6))
2441                         router_ll6 = (struct in6_addr *)NULL;
2442         } else
2443                 router_ll6 = (struct in6_addr *)NULL;
2444
2445         /* ip6 */
2446         ip6 = mtod(m, struct ip6_hdr *);
2447         ip6->ip6_flow = 0;
2448         ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
2449         ip6->ip6_vfc |= IPV6_VERSION;
2450         /* ip6->ip6_plen will be set later */
2451         ip6->ip6_nxt = IPPROTO_ICMPV6;
2452         ip6->ip6_hlim = 255;
2453         /* ip6->ip6_src must be linklocal addr for my outgoing if. */
2454         bcopy(ifp_ll6, &ip6->ip6_src, sizeof(struct in6_addr));
2455         bcopy(&sip6->ip6_src, &ip6->ip6_dst, sizeof(struct in6_addr));
2456
2457         /* ND Redirect */
2458         nd_rd = (struct nd_redirect *)(ip6 + 1);
2459         nd_rd->nd_rd_type = ND_REDIRECT;
2460         nd_rd->nd_rd_code = 0;
2461         nd_rd->nd_rd_reserved = 0;
2462         if (nh->nh_flags & NHF_GATEWAY) {
2463                 /*
2464                  * nd_rd->nd_rd_target must be a link-local address in
2465                  * better router cases.
2466                  */
2467                 if (!router_ll6)
2468                         goto fail;
2469                 bcopy(router_ll6, &nd_rd->nd_rd_target,
2470                     sizeof(nd_rd->nd_rd_target));
2471                 bcopy(&sip6->ip6_dst, &nd_rd->nd_rd_dst,
2472                     sizeof(nd_rd->nd_rd_dst));
2473         } else {
2474                 /* make sure redtgt == reddst */
2475                 bcopy(&sip6->ip6_dst, &nd_rd->nd_rd_target,
2476                     sizeof(nd_rd->nd_rd_target));
2477                 bcopy(&sip6->ip6_dst, &nd_rd->nd_rd_dst,
2478                     sizeof(nd_rd->nd_rd_dst));
2479         }
2480
2481         p = (u_char *)(nd_rd + 1);
2482
2483         if (!router_ll6)
2484                 goto nolladdropt;
2485
2486         {
2487                 /* target lladdr option */
2488                 int len;
2489                 struct nd_opt_hdr *nd_opt;
2490                 char *lladdr;
2491
2492                 ln = nd6_lookup(router_ll6, LLE_SF(AF_INET6,  0), ifp);
2493                 if (ln == NULL)
2494                         goto nolladdropt;
2495
2496                 len = sizeof(*nd_opt) + ifp->if_addrlen;
2497                 len = (len + 7) & ~7;   /* round by 8 */
2498                 /* safety check */
2499                 if (len + (p - (u_char *)ip6) > maxlen)
2500                         goto nolladdropt;
2501
2502                 if (ln->la_flags & LLE_VALID) {
2503                         nd_opt = (struct nd_opt_hdr *)p;
2504                         nd_opt->nd_opt_type = ND_OPT_TARGET_LINKADDR;
2505                         nd_opt->nd_opt_len = len >> 3;
2506                         lladdr = (char *)(nd_opt + 1);
2507                         bcopy(ln->ll_addr, lladdr, ifp->if_addrlen);
2508                         p += len;
2509                 }
2510         }
2511 nolladdropt:
2512         if (ln != NULL)
2513                 LLE_RUNLOCK(ln);
2514
2515         m->m_pkthdr.len = m->m_len = p - (u_char *)ip6;
2516
2517         /* just to be safe */
2518 #ifdef M_DECRYPTED      /*not openbsd*/
2519         if (m0->m_flags & M_DECRYPTED)
2520                 goto noredhdropt;
2521 #endif
2522         if (p - (u_char *)ip6 > maxlen)
2523                 goto noredhdropt;
2524
2525         {
2526                 /* redirected header option */
2527                 int len;
2528                 struct nd_opt_rd_hdr *nd_opt_rh;
2529
2530                 /*
2531                  * compute the maximum size for icmp6 redirect header option.
2532                  * XXX room for auth header?
2533                  */
2534                 len = maxlen - (p - (u_char *)ip6);
2535                 len &= ~7;
2536
2537                 /* This is just for simplicity. */
2538                 if (m0->m_pkthdr.len != m0->m_len) {
2539                         if (m0->m_next) {
2540                                 m_freem(m0->m_next);
2541                                 m0->m_next = NULL;
2542                         }
2543                         m0->m_pkthdr.len = m0->m_len;
2544                 }
2545
2546                 /*
2547                  * Redirected header option spec (RFC2461 4.6.3) talks nothing
2548                  * about padding/truncate rule for the original IP packet.
2549                  * From the discussion on IPv6imp in Feb 1999,
2550                  * the consensus was:
2551                  * - "attach as much as possible" is the goal
2552                  * - pad if not aligned (original size can be guessed by
2553                  *   original ip6 header)
2554                  * Following code adds the padding if it is simple enough,
2555                  * and truncates if not.
2556                  */
2557                 if (m0->m_next || m0->m_pkthdr.len != m0->m_len)
2558                         panic("assumption failed in %s:%d", __FILE__,
2559                             __LINE__);
2560
2561                 if (len - sizeof(*nd_opt_rh) < m0->m_pkthdr.len) {
2562                         /* not enough room, truncate */
2563                         m0->m_pkthdr.len = m0->m_len = len -
2564                             sizeof(*nd_opt_rh);
2565                 } else {
2566                         /* enough room, pad or truncate */
2567                         size_t extra;
2568
2569                         extra = m0->m_pkthdr.len % 8;
2570                         if (extra) {
2571                                 /* pad if easy enough, truncate if not */
2572                                 if (8 - extra <= M_TRAILINGSPACE(m0)) {
2573                                         /* pad */
2574                                         m0->m_len += (8 - extra);
2575                                         m0->m_pkthdr.len += (8 - extra);
2576                                 } else {
2577                                         /* truncate */
2578                                         m0->m_pkthdr.len -= extra;
2579                                         m0->m_len -= extra;
2580                                 }
2581                         }
2582                         len = m0->m_pkthdr.len + sizeof(*nd_opt_rh);
2583                         m0->m_pkthdr.len = m0->m_len = len -
2584                             sizeof(*nd_opt_rh);
2585                 }
2586
2587                 nd_opt_rh = (struct nd_opt_rd_hdr *)p;
2588                 bzero(nd_opt_rh, sizeof(*nd_opt_rh));
2589                 nd_opt_rh->nd_opt_rh_type = ND_OPT_REDIRECTED_HEADER;
2590                 nd_opt_rh->nd_opt_rh_len = len >> 3;
2591                 p += sizeof(*nd_opt_rh);
2592                 m->m_pkthdr.len = m->m_len = p - (u_char *)ip6;
2593
2594                 /* connect m0 to m */
2595                 m_tag_delete_chain(m0, NULL);
2596                 m0->m_flags &= ~M_PKTHDR;
2597                 m->m_next = m0;
2598                 m->m_pkthdr.len = m->m_len + m0->m_len;
2599                 m0 = NULL;
2600         }
2601 noredhdropt:;
2602         if (m0) {
2603                 m_freem(m0);
2604                 m0 = NULL;
2605         }
2606
2607         /* XXX: clear embedded link IDs in the inner header */
2608         in6_clearscope(&sip6->ip6_src);
2609         in6_clearscope(&sip6->ip6_dst);
2610         in6_clearscope(&nd_rd->nd_rd_target);
2611         in6_clearscope(&nd_rd->nd_rd_dst);
2612
2613         ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
2614
2615         nd_rd->nd_rd_cksum = 0;
2616         nd_rd->nd_rd_cksum = in6_cksum(m, IPPROTO_ICMPV6,
2617             sizeof(*ip6), ntohs(ip6->ip6_plen));
2618
2619         if (send_sendso_input_hook != NULL) {
2620                 mtag = m_tag_get(PACKET_TAG_ND_OUTGOING, sizeof(unsigned short),
2621                         M_NOWAIT);
2622                 if (mtag == NULL)
2623                         goto fail;
2624                 *(unsigned short *)(mtag + 1) = nd_rd->nd_rd_type;
2625                 m_tag_prepend(m, mtag);
2626         }
2627
2628         /* send the packet to outside... */
2629         ip6_output(m, NULL, NULL, 0, NULL, &outif, NULL);
2630         if (outif) {
2631                 icmp6_ifstat_inc(outif, ifs6_out_msg);
2632                 icmp6_ifstat_inc(outif, ifs6_out_redirect);
2633         }
2634         ICMP6STAT_INC(icp6s_outhist[ND_REDIRECT]);
2635
2636         return;
2637
2638 fail:
2639         if (m)
2640                 m_freem(m);
2641         if (m0)
2642                 m_freem(m0);
2643 }
2644
2645 /*
2646  * ICMPv6 socket option processing.
2647  */
2648 int
2649 icmp6_ctloutput(struct socket *so, struct sockopt *sopt)
2650 {
2651         int error = 0;
2652         int optlen;
2653         struct inpcb *inp = sotoinpcb(so);
2654         int level, op, optname;
2655
2656         if (sopt) {
2657                 level = sopt->sopt_level;
2658                 op = sopt->sopt_dir;
2659                 optname = sopt->sopt_name;
2660                 optlen = sopt->sopt_valsize;
2661         } else
2662                 level = op = optname = optlen = 0;
2663
2664         if (level != IPPROTO_ICMPV6) {
2665                 return EINVAL;
2666         }
2667
2668         switch (op) {
2669         case PRCO_SETOPT:
2670                 switch (optname) {
2671                 case ICMP6_FILTER:
2672                     {
2673                         struct icmp6_filter ic6f;
2674
2675                         if (optlen != sizeof(ic6f)) {
2676                                 error = EMSGSIZE;
2677                                 break;
2678                         }
2679                         error = sooptcopyin(sopt, &ic6f, optlen, optlen);
2680                         if (error == 0) {
2681                                 INP_WLOCK(inp);
2682                                 *inp->in6p_icmp6filt = ic6f;
2683                                 INP_WUNLOCK(inp);
2684                         }
2685                         break;
2686                     }
2687
2688                 default:
2689                         error = ENOPROTOOPT;
2690                         break;
2691                 }
2692                 break;
2693
2694         case PRCO_GETOPT:
2695                 switch (optname) {
2696                 case ICMP6_FILTER:
2697                     {
2698                         struct icmp6_filter ic6f;
2699
2700                         INP_RLOCK(inp);
2701                         ic6f = *inp->in6p_icmp6filt;
2702                         INP_RUNLOCK(inp);
2703                         error = sooptcopyout(sopt, &ic6f, sizeof(ic6f));
2704                         break;
2705                     }
2706
2707                 default:
2708                         error = ENOPROTOOPT;
2709                         break;
2710                 }
2711                 break;
2712         }
2713
2714         return (error);
2715 }
2716
2717 /*
2718  * Perform rate limit check.
2719  * Returns 0 if it is okay to send the icmp6 packet.
2720  * Returns 1 if the router SHOULD NOT send this icmp6 packet due to rate
2721  * limitation.
2722  *
2723  * XXX per-destination/type check necessary?
2724  *
2725  * dst - not used at this moment
2726  * type - not used at this moment
2727  * code - not used at this moment
2728  */
2729 int
2730 icmp6_ratelimit(const struct in6_addr *dst, const int type,
2731     const int code)
2732 {
2733         int ret;
2734
2735         ret = 0;        /* okay to send */
2736
2737         /* PPS limit */
2738         if (!ppsratecheck(&V_icmp6errppslim_last, &V_icmp6errpps_count,
2739             V_icmp6errppslim)) {
2740                 /* The packet is subject to rate limit */
2741                 ret++;
2742         }
2743
2744         return ret;
2745 }