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/vnet.h>
  97
  98 #include <netinet/in.h>
  99 #include <netinet/in_pcb.h>
 100 #include <netinet/in_var.h>
 101 #include <netinet/ip6.h>
 102 #include <netinet/icmp6.h>
 103 #include <netinet/tcp_var.h>
 104
 105 #include <netinet6/in6_fib.h>
 106 #include <netinet6/in6_ifattach.h>
 107 #include <netinet6/in6_pcb.h>
 108 #include <netinet6/ip6protosw.h>
 109 #include <netinet6/ip6_var.h>
 110 #include <netinet6/scope6_var.h>
 111 #include <netinet6/mld6_var.h>
 112 #include <netinet6/nd6.h>
 113 #include <netinet6/send.h>
 114
 115 extern struct domain inet6domain;
 116
 117 VNET_PCPUSTAT_DEFINE(struct icmp6stat, icmp6stat);
 118 VNET_PCPUSTAT_SYSINIT(icmp6stat);
 119
 120 #ifdef VIMAGE
 121 VNET_PCPUSTAT_SYSUNINIT(icmp6stat);
 122 #endif /* VIMAGE */
 123
 124 VNET_DECLARE(struct inpcbinfo, ripcbinfo);
 125 VNET_DECLARE(struct inpcbhead, ripcb);
 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_ripcb                         VNET(ripcb)
 133 #define V_icmp6errppslim                VNET(icmp6errppslim)
 134 #define V_icmp6errpps_count             VNET(icmp6errpps_count)
 135 #define V_icmp6errppslim_last           VNET(icmp6errppslim_last)
 136 #define V_icmp6_nodeinfo                VNET(icmp6_nodeinfo)
 137
 138 static void icmp6_errcount(int, int);
 139 static int icmp6_rip6_input(struct mbuf **, int);
 140 static int icmp6_ratelimit(const struct in6_addr *, const int, const int);
 141 static const char *icmp6_redirect_diag(struct in6_addr *,
 142         struct in6_addr *, struct in6_addr *);
 143 static struct mbuf *ni6_input(struct mbuf *, int);
 144 static struct mbuf *ni6_nametodns(const char *, int, int);
 145 static int ni6_dnsmatch(const char *, int, const char *, int);
 146 static int ni6_addrs(struct icmp6_nodeinfo *, struct mbuf *,
 147                           struct ifnet **, struct in6_addr *);
 148 static int ni6_store_addrs(struct icmp6_nodeinfo *, struct icmp6_nodeinfo *,
 149                                 struct ifnet *, int);
 150 static int icmp6_notify_error(struct mbuf **, int, int, int);
 151
 152 /*
 153  * Kernel module interface for updating icmp6stat.  The argument is an index
 154  * into icmp6stat treated as an array of u_quad_t.  While this encodes the
 155  * general layout of icmp6stat into the caller, it doesn't encode its
 156  * location, so that future changes to add, for example, per-CPU stats
 157  * support won't cause binary compatibility problems for kernel modules.
 158  */
 159 void
 160 kmod_icmp6stat_inc(int statnum)
 161 {
 162
 163         counter_u64_add(VNET(icmp6stat)[statnum], 1);
 164 }
 165
 166 static void
 167 icmp6_errcount(int type, int code)
 168 {
 169         switch (type) {
 170         case ICMP6_DST_UNREACH:
 171                 switch (code) {
 172                 case ICMP6_DST_UNREACH_NOROUTE:
 173                         ICMP6STAT_INC(icp6s_odst_unreach_noroute);
 174                         return;
 175                 case ICMP6_DST_UNREACH_ADMIN:
 176                         ICMP6STAT_INC(icp6s_odst_unreach_admin);
 177                         return;
 178                 case ICMP6_DST_UNREACH_BEYONDSCOPE:
 179                         ICMP6STAT_INC(icp6s_odst_unreach_beyondscope);
 180                         return;
 181                 case ICMP6_DST_UNREACH_ADDR:
 182                         ICMP6STAT_INC(icp6s_odst_unreach_addr);
 183                         return;
 184                 case ICMP6_DST_UNREACH_NOPORT:
 185                         ICMP6STAT_INC(icp6s_odst_unreach_noport);
 186                         return;
 187                 }
 188                 break;
 189         case ICMP6_PACKET_TOO_BIG:
 190                 ICMP6STAT_INC(icp6s_opacket_too_big);
 191                 return;
 192         case ICMP6_TIME_EXCEEDED:
 193                 switch (code) {
 194                 case ICMP6_TIME_EXCEED_TRANSIT:
 195                         ICMP6STAT_INC(icp6s_otime_exceed_transit);
 196                         return;
 197                 case ICMP6_TIME_EXCEED_REASSEMBLY:
 198                         ICMP6STAT_INC(icp6s_otime_exceed_reassembly);
 199                         return;
 200                 }
 201                 break;
 202         case ICMP6_PARAM_PROB:
 203                 switch (code) {
 204                 case ICMP6_PARAMPROB_HEADER:
 205                         ICMP6STAT_INC(icp6s_oparamprob_header);
 206                         return;
 207                 case ICMP6_PARAMPROB_NEXTHEADER:
 208                         ICMP6STAT_INC(icp6s_oparamprob_nextheader);
 209                         return;
 210                 case ICMP6_PARAMPROB_OPTION:
 211                         ICMP6STAT_INC(icp6s_oparamprob_option);
 212                         return;
 213                 }
 214                 break;
 215         case ND_REDIRECT:
 216                 ICMP6STAT_INC(icp6s_oredirect);
 217                 return;
 218         }
 219         ICMP6STAT_INC(icp6s_ounknown);
 220 }
 221
 222 /*
 223  * A wrapper function for icmp6_error() necessary when the erroneous packet
 224  * may not contain enough scope zone information.
 225  */
 226 void
 227 icmp6_error2(struct mbuf *m, int type, int code, int param,
 228     struct ifnet *ifp)
 229 {
 230         struct ip6_hdr *ip6;
 231
 232         if (ifp == NULL)
 233                 return;
 234
 235 #ifndef PULLDOWN_TEST
 236         IP6_EXTHDR_CHECK(m, 0, sizeof(struct ip6_hdr), );
 237 #else
 238         if (m->m_len < sizeof(struct ip6_hdr)) {
 239                 m = m_pullup(m, sizeof(struct ip6_hdr));
 240                 if (m == NULL)
 241                         return;
 242         }
 243 #endif
 244
 245         ip6 = mtod(m, struct ip6_hdr *);
 246
 247         if (in6_setscope(&ip6->ip6_src, ifp, NULL) != 0)
 248                 return;
 249         if (in6_setscope(&ip6->ip6_dst, ifp, NULL) != 0)
 250                 return;
 251
 252         icmp6_error(m, type, code, param);
 253 }
 254
 255 /*
 256  * Generate an error packet of type error in response to bad IP6 packet.
 257  */
 258 void
 259 icmp6_error(struct mbuf *m, int type, int code, int param)
 260 {
 261         struct ip6_hdr *oip6, *nip6;
 262         struct icmp6_hdr *icmp6;
 263         u_int preplen;
 264         int off;
 265         int nxt;
 266
 267         ICMP6STAT_INC(icp6s_error);
 268
 269         /* count per-type-code statistics */
 270         icmp6_errcount(type, code);
 271
 272 #ifdef M_DECRYPTED      /*not openbsd*/
 273         if (m->m_flags & M_DECRYPTED) {
 274                 ICMP6STAT_INC(icp6s_canterror);
 275                 goto freeit;
 276         }
 277 #endif
 278
 279 #ifndef PULLDOWN_TEST
 280         IP6_EXTHDR_CHECK(m, 0, sizeof(struct ip6_hdr), );
 281 #else
 282         if (m->m_len < sizeof(struct ip6_hdr)) {
 283                 m = m_pullup(m, sizeof(struct ip6_hdr));
 284                 if (m == NULL)
 285                         return;
 286         }
 287 #endif
 288         oip6 = mtod(m, struct ip6_hdr *);
 289
 290         /*
 291          * If the destination address of the erroneous packet is a multicast
 292          * address, or the packet was sent using link-layer multicast,
 293          * we should basically suppress sending an error (RFC 2463, Section
 294          * 2.4).
 295          * We have two exceptions (the item e.2 in that section):
 296          * - the Packet Too Big message can be sent for path MTU discovery.
 297          * - the Parameter Problem Message that can be allowed an icmp6 error
 298          *   in the option type field.  This check has been done in
 299          *   ip6_unknown_opt(), so we can just check the type and code.
 300          */
 301         if ((m->m_flags & (M_BCAST|M_MCAST) ||
 302              IN6_IS_ADDR_MULTICAST(&oip6->ip6_dst)) &&
 303             (type != ICMP6_PACKET_TOO_BIG &&
 304              (type != ICMP6_PARAM_PROB ||
 305               code != ICMP6_PARAMPROB_OPTION)))
 306                 goto freeit;
 307
 308         /*
 309          * RFC 2463, 2.4 (e.5): source address check.
 310          * XXX: the case of anycast source?
 311          */
 312         if (IN6_IS_ADDR_UNSPECIFIED(&oip6->ip6_src) ||
 313             IN6_IS_ADDR_MULTICAST(&oip6->ip6_src))
 314                 goto freeit;
 315
 316         /*
 317          * If we are about to send ICMPv6 against ICMPv6 error/redirect,
 318          * don't do it.
 319          */
 320         nxt = -1;
 321         off = ip6_lasthdr(m, 0, IPPROTO_IPV6, &nxt);
 322         if (off >= 0 && nxt == IPPROTO_ICMPV6) {
 323                 struct icmp6_hdr *icp;
 324
 325 #ifndef PULLDOWN_TEST
 326                 IP6_EXTHDR_CHECK(m, 0, off + sizeof(struct icmp6_hdr), );
 327                 icp = (struct icmp6_hdr *)(mtod(m, caddr_t) + off);
 328 #else
 329                 IP6_EXTHDR_GET(icp, struct icmp6_hdr *, m, off,
 330                         sizeof(*icp));
 331                 if (icp == NULL) {
 332                         ICMP6STAT_INC(icp6s_tooshort);
 333                         return;
 334                 }
 335 #endif
 336                 if (icp->icmp6_type < ICMP6_ECHO_REQUEST ||
 337                     icp->icmp6_type == ND_REDIRECT) {
 338                         /*
 339                          * ICMPv6 error
 340                          * Special case: for redirect (which is
 341                          * informational) we must not send icmp6 error.
 342                          */
 343                         ICMP6STAT_INC(icp6s_canterror);
 344                         goto freeit;
 345                 } else {
 346                         /* ICMPv6 informational - send the error */
 347                 }
 348         } else {
 349                 /* non-ICMPv6 - send the error */
 350         }
 351
 352         oip6 = mtod(m, struct ip6_hdr *); /* adjust pointer */
 353
 354         /* Finally, do rate limitation check. */
 355         if (icmp6_ratelimit(&oip6->ip6_src, type, code)) {
 356                 ICMP6STAT_INC(icp6s_toofreq);
 357                 goto freeit;
 358         }
 359
 360         /*
 361          * OK, ICMP6 can be generated.
 362          */
 363
 364         if (m->m_pkthdr.len >= ICMPV6_PLD_MAXLEN)
 365                 m_adj(m, ICMPV6_PLD_MAXLEN - m->m_pkthdr.len);
 366
 367         preplen = sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr);
 368         M_PREPEND(m, preplen, M_NOWAIT);        /* FIB is also copied over. */
 369         if (m == NULL) {
 370                 nd6log((LOG_DEBUG, "ENOBUFS in icmp6_error %d\n", __LINE__));
 371                 return;
 372         }
 373
 374         nip6 = mtod(m, struct ip6_hdr *);
 375         nip6->ip6_src  = oip6->ip6_src;
 376         nip6->ip6_dst  = oip6->ip6_dst;
 377
 378         in6_clearscope(&oip6->ip6_src);
 379         in6_clearscope(&oip6->ip6_dst);
 380
 381         icmp6 = (struct icmp6_hdr *)(nip6 + 1);
 382         icmp6->icmp6_type = type;
 383         icmp6->icmp6_code = code;
 384         icmp6->icmp6_pptr = htonl((u_int32_t)param);
 385
 386         ICMP6STAT_INC(icp6s_outhist[type]);
 387         icmp6_reflect(m, sizeof(struct ip6_hdr)); /* header order: IPv6 - ICMPv6 */
 388
 389         return;
 390
 391   freeit:
 392         /*
 393          * If we can't tell whether or not we can generate ICMP6, free it.
 394          */
 395         m_freem(m);
 396 }
 397
 398 /*
 399  * Process a received ICMP6 message.
 400  */
 401 int
 402 icmp6_input(struct mbuf **mp, int *offp, int proto)
 403 {
 404         struct mbuf *m = *mp, *n;
 405         struct ifnet *ifp;
 406         struct ip6_hdr *ip6, *nip6;
 407         struct icmp6_hdr *icmp6, *nicmp6;
 408         int off = *offp;
 409         int icmp6len = m->m_pkthdr.len - *offp;
 410         int code, sum, noff;
 411         char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
 412         int ip6len, error;
 413
 414         ifp = m->m_pkthdr.rcvif;
 415
 416 #ifndef PULLDOWN_TEST
 417         IP6_EXTHDR_CHECK(m, off, sizeof(struct icmp6_hdr), IPPROTO_DONE);
 418         /* m might change if M_LOOP.  So, call mtod after this */
 419 #endif
 420
 421         /*
 422          * Locate icmp6 structure in mbuf, and check
 423          * that not corrupted and of at least minimum length
 424          */
 425
 426         ip6 = mtod(m, struct ip6_hdr *);
 427         ip6len = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen);
 428         if (icmp6len < sizeof(struct icmp6_hdr)) {
 429                 ICMP6STAT_INC(icp6s_tooshort);
 430                 goto freeit;
 431         }
 432
 433         /*
 434          * Check multicast group membership.
 435          * Note: SSM filters are not applied for ICMPv6 traffic.
 436          */
 437         if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
 438                 struct in6_multi        *inm;
 439
 440                 inm = in6m_lookup(ifp, &ip6->ip6_dst);
 441                 if (inm == NULL) {
 442                         IP6STAT_INC(ip6s_notmember);
 443                         in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
 444                         goto freeit;
 445                 }
 446         }
 447
 448         /*
 449          * calculate the checksum
 450          */
 451 #ifndef PULLDOWN_TEST
 452         icmp6 = (struct icmp6_hdr *)((caddr_t)ip6 + off);
 453 #else
 454         IP6_EXTHDR_GET(icmp6, struct icmp6_hdr *, m, off, sizeof(*icmp6));
 455         if (icmp6 == NULL) {
 456                 ICMP6STAT_INC(icp6s_tooshort);
 457                 return IPPROTO_DONE;
 458         }
 459 #endif
 460         code = icmp6->icmp6_code;
 461
 462         if ((sum = in6_cksum(m, IPPROTO_ICMPV6, off, icmp6len)) != 0) {
 463                 nd6log((LOG_ERR,
 464                     "ICMP6 checksum error(%d|%x) %s\n",
 465                     icmp6->icmp6_type, sum,
 466                     ip6_sprintf(ip6bufs, &ip6->ip6_src)));
 467                 ICMP6STAT_INC(icp6s_checksum);
 468                 goto freeit;
 469         }
 470
 471         ICMP6STAT_INC(icp6s_inhist[icmp6->icmp6_type]);
 472         icmp6_ifstat_inc(ifp, ifs6_in_msg);
 473         if (icmp6->icmp6_type < ICMP6_INFOMSG_MASK)
 474                 icmp6_ifstat_inc(ifp, ifs6_in_error);
 475
 476         switch (icmp6->icmp6_type) {
 477         case ICMP6_DST_UNREACH:
 478                 icmp6_ifstat_inc(ifp, ifs6_in_dstunreach);
 479                 switch (code) {
 480                 case ICMP6_DST_UNREACH_NOROUTE:
 481                 case ICMP6_DST_UNREACH_ADDR:    /* PRC_HOSTDEAD is a DOS */
 482                         code = PRC_UNREACH_NET;
 483                         break;
 484                 case ICMP6_DST_UNREACH_ADMIN:
 485                         icmp6_ifstat_inc(ifp, ifs6_in_adminprohib);
 486                         code = PRC_UNREACH_ADMIN_PROHIB;
 487                         break;
 488                 case ICMP6_DST_UNREACH_BEYONDSCOPE:
 489                         /* I mean "source address was incorrect." */
 490                         code = PRC_PARAMPROB;
 491                         break;
 492                 case ICMP6_DST_UNREACH_NOPORT:
 493                         code = PRC_UNREACH_PORT;
 494                         break;
 495                 default:
 496                         goto badcode;
 497                 }
 498                 goto deliver;
 499                 break;
 500
 501         case ICMP6_PACKET_TOO_BIG:
 502                 icmp6_ifstat_inc(ifp, ifs6_in_pkttoobig);
 503
 504                 /* validation is made in icmp6_mtudisc_update */
 505
 506                 code = PRC_MSGSIZE;
 507
 508                 /*
 509                  * Updating the path MTU will be done after examining
 510                  * intermediate extension headers.
 511                  */
 512                 goto deliver;
 513                 break;
 514
 515         case ICMP6_TIME_EXCEEDED:
 516                 icmp6_ifstat_inc(ifp, ifs6_in_timeexceed);
 517                 switch (code) {
 518                 case ICMP6_TIME_EXCEED_TRANSIT:
 519                         code = PRC_TIMXCEED_INTRANS;
 520                         break;
 521                 case ICMP6_TIME_EXCEED_REASSEMBLY:
 522                         code = PRC_TIMXCEED_REASS;
 523                         break;
 524                 default:
 525                         goto badcode;
 526                 }
 527                 goto deliver;
 528                 break;
 529
 530         case ICMP6_PARAM_PROB:
 531                 icmp6_ifstat_inc(ifp, ifs6_in_paramprob);
 532                 switch (code) {
 533                 case ICMP6_PARAMPROB_NEXTHEADER:
 534                         code = PRC_UNREACH_PROTOCOL;
 535                         break;
 536                 case ICMP6_PARAMPROB_HEADER:
 537                 case ICMP6_PARAMPROB_OPTION:
 538                         code = PRC_PARAMPROB;
 539                         break;
 540                 default:
 541                         goto badcode;
 542                 }
 543                 goto deliver;
 544                 break;
 545
 546         case ICMP6_ECHO_REQUEST:
 547                 icmp6_ifstat_inc(ifp, ifs6_in_echo);
 548                 if (code != 0)
 549                         goto badcode;
 550                 if ((n = m_copym(m, 0, M_COPYALL, M_NOWAIT)) == NULL) {
 551                         /* Give up remote */
 552                         break;
 553                 }
 554                 if (!M_WRITABLE(n)
 555                  || n->m_len < off + sizeof(struct icmp6_hdr)) {
 556                         struct mbuf *n0 = n;
 557                         int n0len;
 558
 559                         CTASSERT(sizeof(*nip6) + sizeof(*nicmp6) <= MHLEN);
 560                         n = m_gethdr(M_NOWAIT, n0->m_type);
 561                         if (n == NULL) {
 562                                 /* Give up remote */
 563                                 m_freem(n0);
 564                                 break;
 565                         }
 566
 567                         m_move_pkthdr(n, n0);   /* FIB copied. */
 568                         n0len = n0->m_pkthdr.len;       /* save for use below */
 569                         /*
 570                          * Copy IPv6 and ICMPv6 only.
 571                          */
 572                         nip6 = mtod(n, struct ip6_hdr *);
 573                         bcopy(ip6, nip6, sizeof(struct ip6_hdr));
 574                         nicmp6 = (struct icmp6_hdr *)(nip6 + 1);
 575                         bcopy(icmp6, nicmp6, sizeof(struct icmp6_hdr));
 576                         noff = sizeof(struct ip6_hdr);
 577                         /* new mbuf contains only ipv6+icmpv6 headers */
 578                         n->m_len = noff + sizeof(struct icmp6_hdr);
 579                         /*
 580                          * Adjust mbuf.  ip6_plen will be adjusted in
 581                          * ip6_output().
 582                          */
 583                         m_adj(n0, off + sizeof(struct icmp6_hdr));
 584                         /* recalculate complete packet size */
 585                         n->m_pkthdr.len = n0len + (noff - off);
 586                         n->m_next = n0;
 587                 } else {
 588                         IP6_EXTHDR_GET(nicmp6, struct icmp6_hdr *, n, off,
 589                             sizeof(*nicmp6));
 590                         noff = off;
 591                 }
 592                 if (n) {
 593                         nicmp6->icmp6_type = ICMP6_ECHO_REPLY;
 594                         nicmp6->icmp6_code = 0;
 595                         ICMP6STAT_INC(icp6s_reflect);
 596                         ICMP6STAT_INC(icp6s_outhist[ICMP6_ECHO_REPLY]);
 597                         icmp6_reflect(n, noff);
 598                 }
 599                 break;
 600
 601         case ICMP6_ECHO_REPLY:
 602                 icmp6_ifstat_inc(ifp, ifs6_in_echoreply);
 603                 if (code != 0)
 604                         goto badcode;
 605                 break;
 606
 607         case MLD_LISTENER_QUERY:
 608         case MLD_LISTENER_REPORT:
 609         case MLD_LISTENER_DONE:
 610         case MLDV2_LISTENER_REPORT:
 611                 /*
 612                  * Drop MLD traffic which is not link-local, has a hop limit
 613                  * of greater than 1 hop, or which does not have the
 614                  * IPv6 HBH Router Alert option.
 615                  * As IPv6 HBH options are stripped in ip6_input() we must
 616                  * check an mbuf header flag.
 617                  * XXX Should we also sanity check that these messages
 618                  * were directed to a link-local multicast prefix?
 619                  */
 620                 if ((ip6->ip6_hlim != 1) || (m->m_flags & M_RTALERT_MLD) == 0)
 621                         goto freeit;
 622                 if (mld_input(m, off, icmp6len) != 0)
 623                         return (IPPROTO_DONE);
 624                 /* m stays. */
 625                 break;
 626
 627         case ICMP6_WRUREQUEST:  /* ICMP6_FQDN_QUERY */
 628             {
 629                 enum { WRU, FQDN } mode;
 630
 631                 if (!V_icmp6_nodeinfo)
 632                         break;
 633
 634                 if (icmp6len == sizeof(struct icmp6_hdr) + 4)
 635                         mode = WRU;
 636                 else if (icmp6len >= sizeof(struct icmp6_nodeinfo))
 637                         mode = FQDN;
 638                 else
 639                         goto badlen;
 640
 641                 if (mode == FQDN) {
 642 #ifndef PULLDOWN_TEST
 643                         IP6_EXTHDR_CHECK(m, off, sizeof(struct icmp6_nodeinfo),
 644                             IPPROTO_DONE);
 645 #endif
 646                         n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
 647                         if (n)
 648                                 n = ni6_input(n, off);
 649                         /* XXX meaningless if n == NULL */
 650                         noff = sizeof(struct ip6_hdr);
 651                 } else {
 652                         struct prison *pr;
 653                         u_char *p;
 654                         int maxhlen, hlen;
 655
 656                         /*
 657                          * XXX: this combination of flags is pointless,
 658                          * but should we keep this for compatibility?
 659                          */
 660                         if ((V_icmp6_nodeinfo & (ICMP6_NODEINFO_FQDNOK |
 661                             ICMP6_NODEINFO_TMPADDROK)) !=
 662                             (ICMP6_NODEINFO_FQDNOK | ICMP6_NODEINFO_TMPADDROK))
 663                                 break;
 664
 665                         if (code != 0)
 666                                 goto badcode;
 667
 668                         CTASSERT(sizeof(*nip6) + sizeof(*nicmp6) + 4 <= MHLEN);
 669                         n = m_gethdr(M_NOWAIT, m->m_type);
 670                         if (n == NULL) {
 671                                 /* Give up remote */
 672                                 break;
 673                         }
 674                         if (!m_dup_pkthdr(n, m, M_NOWAIT)) {
 675                                 /*
 676                                  * Previous code did a blind M_COPY_PKTHDR
 677                                  * and said "just for rcvif".  If true, then
 678                                  * we could tolerate the dup failing (due to
 679                                  * the deep copy of the tag chain).  For now
 680                                  * be conservative and just fail.
 681                                  */
 682                                 m_free(n);
 683                                 n = NULL;
 684                                 break;
 685                         }
 686                         maxhlen = M_TRAILINGSPACE(n) -
 687                             (sizeof(*nip6) + sizeof(*nicmp6) + 4);
 688                         pr = curthread->td_ucred->cr_prison;
 689                         mtx_lock(&pr->pr_mtx);
 690                         hlen = strlen(pr->pr_hostname);
 691                         if (maxhlen > hlen)
 692                                 maxhlen = hlen;
 693                         /*
 694                          * Copy IPv6 and ICMPv6 only.
 695                          */
 696                         nip6 = mtod(n, struct ip6_hdr *);
 697                         bcopy(ip6, nip6, sizeof(struct ip6_hdr));
 698                         nicmp6 = (struct icmp6_hdr *)(nip6 + 1);
 699                         bcopy(icmp6, nicmp6, sizeof(struct icmp6_hdr));
 700                         p = (u_char *)(nicmp6 + 1);
 701                         bzero(p, 4);
 702                         /* meaningless TTL */
 703                         bcopy(pr->pr_hostname, p + 4, maxhlen);
 704                         mtx_unlock(&pr->pr_mtx);
 705                         noff = sizeof(struct ip6_hdr);
 706                         n->m_pkthdr.len = n->m_len = sizeof(struct ip6_hdr) +
 707                                 sizeof(struct icmp6_hdr) + 4 + maxhlen;
 708                         nicmp6->icmp6_type = ICMP6_WRUREPLY;
 709                         nicmp6->icmp6_code = 0;
 710                 }
 711                 if (n) {
 712                         ICMP6STAT_INC(icp6s_reflect);
 713                         ICMP6STAT_INC(icp6s_outhist[ICMP6_WRUREPLY]);
 714                         icmp6_reflect(n, noff);
 715                 }
 716                 break;
 717             }
 718
 719         case ICMP6_WRUREPLY:
 720                 if (code != 0)
 721                         goto badcode;
 722                 break;
 723
 724         case ND_ROUTER_SOLICIT:
 725                 icmp6_ifstat_inc(ifp, ifs6_in_routersolicit);
 726                 if (code != 0)
 727                         goto badcode;
 728                 if (icmp6len < sizeof(struct nd_router_solicit))
 729                         goto badlen;
 730                 if (send_sendso_input_hook != NULL) {
 731                         IP6_EXTHDR_CHECK(m, off, icmp6len, IPPROTO_DONE);
 732                         error = send_sendso_input_hook(m, ifp, SND_IN, ip6len);
 733                         if (error == 0) {
 734                                 m = NULL;
 735                                 goto freeit;
 736                         }
 737                 }
 738                 n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
 739                 nd6_rs_input(m, off, icmp6len);
 740                 m = n;
 741                 if (m == NULL)
 742                         goto freeit;
 743                 break;
 744
 745         case ND_ROUTER_ADVERT:
 746                 icmp6_ifstat_inc(ifp, ifs6_in_routeradvert);
 747                 if (code != 0)
 748                         goto badcode;
 749                 if (icmp6len < sizeof(struct nd_router_advert))
 750                         goto badlen;
 751                 if (send_sendso_input_hook != NULL) {
 752                         error = send_sendso_input_hook(m, ifp, SND_IN, ip6len);
 753                         if (error == 0) {
 754                                 m = NULL;
 755                                 goto freeit;
 756                         }
 757                 }
 758                 n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
 759                 nd6_ra_input(m, off, icmp6len);
 760                 m = n;
 761                 if (m == NULL)
 762                         goto freeit;
 763                 break;
 764
 765         case ND_NEIGHBOR_SOLICIT:
 766                 icmp6_ifstat_inc(ifp, ifs6_in_neighborsolicit);
 767                 if (code != 0)
 768                         goto badcode;
 769                 if (icmp6len < sizeof(struct nd_neighbor_solicit))
 770                         goto badlen;
 771                 if (send_sendso_input_hook != NULL) {
 772                         error = send_sendso_input_hook(m, ifp, SND_IN, ip6len);
 773                         if (error == 0) {
 774                                 m = NULL;
 775                                 goto freeit;
 776                         }
 777                 }
 778                 n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
 779                 nd6_ns_input(m, off, icmp6len);
 780                 m = n;
 781                 if (m == NULL)
 782                         goto freeit;
 783                 break;
 784
 785         case ND_NEIGHBOR_ADVERT:
 786                 icmp6_ifstat_inc(ifp, ifs6_in_neighboradvert);
 787                 if (code != 0)
 788                         goto badcode;
 789                 if (icmp6len < sizeof(struct nd_neighbor_advert))
 790                         goto badlen;
 791                 if (send_sendso_input_hook != NULL) {
 792                         error = send_sendso_input_hook(m, ifp, SND_IN, ip6len);
 793                         if (error == 0) {
 794                                 m = NULL;
 795                                 goto freeit;
 796                         }
 797                 }
 798                 n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
 799                 nd6_na_input(m, off, icmp6len);
 800                 m = n;
 801                 if (m == NULL)
 802                         goto freeit;
 803                 break;
 804
 805         case ND_REDIRECT:
 806                 icmp6_ifstat_inc(ifp, ifs6_in_redirect);
 807                 if (code != 0)
 808                         goto badcode;
 809                 if (icmp6len < sizeof(struct nd_redirect))
 810                         goto badlen;
 811                 if (send_sendso_input_hook != NULL) {
 812                         error = send_sendso_input_hook(m, ifp, SND_IN, ip6len);
 813                         if (error == 0) {
 814                                 m = NULL;
 815                                 goto freeit;
 816                         }
 817                 }
 818                 n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
 819                 icmp6_redirect_input(m, off);
 820                 m = n;
 821                 if (m == NULL)
 822                         goto freeit;
 823                 break;
 824
 825         case ICMP6_ROUTER_RENUMBERING:
 826                 if (code != ICMP6_ROUTER_RENUMBERING_COMMAND &&
 827                     code != ICMP6_ROUTER_RENUMBERING_RESULT)
 828                         goto badcode;
 829                 if (icmp6len < sizeof(struct icmp6_router_renum))
 830                         goto badlen;
 831                 break;
 832
 833         default:
 834                 nd6log((LOG_DEBUG,
 835                     "icmp6_input: unknown type %d(src=%s, dst=%s, ifid=%d)\n",
 836                     icmp6->icmp6_type, ip6_sprintf(ip6bufs, &ip6->ip6_src),
 837                     ip6_sprintf(ip6bufd, &ip6->ip6_dst),
 838                     ifp ? ifp->if_index : 0));
 839                 if (icmp6->icmp6_type < ICMP6_ECHO_REQUEST) {
 840                         /* ICMPv6 error: MUST deliver it by spec... */
 841                         code = PRC_NCMDS;
 842                         /* deliver */
 843                 } else {
 844                         /* ICMPv6 informational: MUST not deliver */
 845                         break;
 846                 }
 847         deliver:
 848                 if (icmp6_notify_error(&m, off, icmp6len, code) != 0) {
 849                         /* In this case, m should've been freed. */
 850                         return (IPPROTO_DONE);
 851                 }
 852                 break;
 853
 854         badcode:
 855                 ICMP6STAT_INC(icp6s_badcode);
 856                 break;
 857
 858         badlen:
 859                 ICMP6STAT_INC(icp6s_badlen);
 860                 break;
 861         }
 862
 863         /* deliver the packet to appropriate sockets */
 864         icmp6_rip6_input(&m, *offp);
 865
 866         return IPPROTO_DONE;
 867
 868  freeit:
 869         m_freem(m);
 870         return IPPROTO_DONE;
 871 }
 872
 873 static int
 874 icmp6_notify_error(struct mbuf **mp, int off, int icmp6len, int code)
 875 {
 876         struct mbuf *m = *mp;
 877         struct icmp6_hdr *icmp6;
 878         struct ip6_hdr *eip6;
 879         u_int32_t notifymtu;
 880         struct sockaddr_in6 icmp6src, icmp6dst;
 881
 882         if (icmp6len < sizeof(struct icmp6_hdr) + sizeof(struct ip6_hdr)) {
 883                 ICMP6STAT_INC(icp6s_tooshort);
 884                 goto freeit;
 885         }
 886 #ifndef PULLDOWN_TEST
 887         IP6_EXTHDR_CHECK(m, off,
 888             sizeof(struct icmp6_hdr) + sizeof(struct ip6_hdr), -1);
 889         icmp6 = (struct icmp6_hdr *)(mtod(m, caddr_t) + off);
 890 #else
 891         IP6_EXTHDR_GET(icmp6, struct icmp6_hdr *, m, off,
 892             sizeof(*icmp6) + sizeof(struct ip6_hdr));
 893         if (icmp6 == NULL) {
 894                 ICMP6STAT_INC(icp6s_tooshort);
 895                 return (-1);
 896         }
 897 #endif
 898         eip6 = (struct ip6_hdr *)(icmp6 + 1);
 899
 900         /* Detect the upper level protocol */
 901         {
 902                 void (*ctlfunc)(int, struct sockaddr *, void *);
 903                 u_int8_t nxt = eip6->ip6_nxt;
 904                 int eoff = off + sizeof(struct icmp6_hdr) +
 905                     sizeof(struct ip6_hdr);
 906                 struct ip6ctlparam ip6cp;
 907                 struct in6_addr *finaldst = NULL;
 908                 int icmp6type = icmp6->icmp6_type;
 909                 struct ip6_frag *fh;
 910                 struct ip6_rthdr *rth;
 911                 struct ip6_rthdr0 *rth0;
 912                 int rthlen;
 913
 914                 while (1) { /* XXX: should avoid infinite loop explicitly? */
 915                         struct ip6_ext *eh;
 916
 917                         switch (nxt) {
 918                         case IPPROTO_HOPOPTS:
 919                         case IPPROTO_DSTOPTS:
 920                         case IPPROTO_AH:
 921 #ifndef PULLDOWN_TEST
 922                                 IP6_EXTHDR_CHECK(m, 0,
 923                                     eoff + sizeof(struct ip6_ext), -1);
 924                                 eh = (struct ip6_ext *)(mtod(m, caddr_t) + eoff);
 925 #else
 926                                 IP6_EXTHDR_GET(eh, struct ip6_ext *, m,
 927                                     eoff, sizeof(*eh));
 928                                 if (eh == NULL) {
 929                                         ICMP6STAT_INC(icp6s_tooshort);
 930                                         return (-1);
 931                                 }
 932 #endif
 933
 934                                 if (nxt == IPPROTO_AH)
 935                                         eoff += (eh->ip6e_len + 2) << 2;
 936                                 else
 937                                         eoff += (eh->ip6e_len + 1) << 3;
 938                                 nxt = eh->ip6e_nxt;
 939                                 break;
 940                         case IPPROTO_ROUTING:
 941                                 /*
 942                                  * When the erroneous packet contains a
 943                                  * routing header, we should examine the
 944                                  * header to determine the final destination.
 945                                  * Otherwise, we can't properly update
 946                                  * information that depends on the final
 947                                  * destination (e.g. path MTU).
 948                                  */
 949 #ifndef PULLDOWN_TEST
 950                                 IP6_EXTHDR_CHECK(m, 0, eoff + sizeof(*rth), -1);
 951                                 rth = (struct ip6_rthdr *)
 952                                     (mtod(m, caddr_t) + eoff);
 953 #else
 954                                 IP6_EXTHDR_GET(rth, struct ip6_rthdr *, m,
 955                                     eoff, sizeof(*rth));
 956                                 if (rth == NULL) {
 957                                         ICMP6STAT_INC(icp6s_tooshort);
 958                                         return (-1);
 959                                 }
 960 #endif
 961                                 rthlen = (rth->ip6r_len + 1) << 3;
 962                                 /*
 963                                  * XXX: currently there is no
 964                                  * officially defined type other
 965                                  * than type-0.
 966                                  * Note that if the segment left field
 967                                  * is 0, all intermediate hops must
 968                                  * have been passed.
 969                                  */
 970                                 if (rth->ip6r_segleft &&
 971                                     rth->ip6r_type == IPV6_RTHDR_TYPE_0) {
 972                                         int hops;
 973
 974 #ifndef PULLDOWN_TEST
 975                                         IP6_EXTHDR_CHECK(m, 0, eoff + rthlen, -1);
 976                                         rth0 = (struct ip6_rthdr0 *)
 977                                             (mtod(m, caddr_t) + eoff);
 978 #else
 979                                         IP6_EXTHDR_GET(rth0,
 980                                             struct ip6_rthdr0 *, m,
 981                                             eoff, rthlen);
 982                                         if (rth0 == NULL) {
 983                                                 ICMP6STAT_INC(icp6s_tooshort);
 984                                                 return (-1);
 985                                         }
 986 #endif
 987                                         /* just ignore a bogus header */
 988                                         if ((rth0->ip6r0_len % 2) == 0 &&
 989                                             (hops = rth0->ip6r0_len/2))
 990                                                 finaldst = (struct in6_addr *)(rth0 + 1) + (hops - 1);
 991                                 }
 992                                 eoff += rthlen;
 993                                 nxt = rth->ip6r_nxt;
 994                                 break;
 995                         case IPPROTO_FRAGMENT:
 996 #ifndef PULLDOWN_TEST
 997                                 IP6_EXTHDR_CHECK(m, 0, eoff +
 998                                     sizeof(struct ip6_frag), -1);
 999                                 fh = (struct ip6_frag *)(mtod(m, caddr_t) +
1000                                     eoff);
1001 #else
1002                                 IP6_EXTHDR_GET(fh, struct ip6_frag *, m,
1003                                     eoff, sizeof(*fh));
1004                                 if (fh == NULL) {
1005                                         ICMP6STAT_INC(icp6s_tooshort);
1006                                         return (-1);
1007                                 }
1008 #endif
1009                                 /*
1010                                  * Data after a fragment header is meaningless
1011                                  * unless it is the first fragment, but
1012                                  * we'll go to the notify label for path MTU
1013                                  * discovery.
1014                                  */
1015                                 if (fh->ip6f_offlg & IP6F_OFF_MASK)
1016                                         goto notify;
1017
1018                                 eoff += sizeof(struct ip6_frag);
1019                                 nxt = fh->ip6f_nxt;
1020                                 break;
1021                         default:
1022                                 /*
1023                                  * This case includes ESP and the No Next
1024                                  * Header.  In such cases going to the notify
1025                                  * label does not have any meaning
1026                                  * (i.e. ctlfunc will be NULL), but we go
1027                                  * anyway since we might have to update
1028                                  * path MTU information.
1029                                  */
1030                                 goto notify;
1031                         }
1032                 }
1033           notify:
1034 #ifndef PULLDOWN_TEST
1035                 icmp6 = (struct icmp6_hdr *)(mtod(m, caddr_t) + off);
1036 #else
1037                 IP6_EXTHDR_GET(icmp6, struct icmp6_hdr *, m, off,
1038                     sizeof(*icmp6) + sizeof(struct ip6_hdr));
1039                 if (icmp6 == NULL) {
1040                         ICMP6STAT_INC(icp6s_tooshort);
1041                         return (-1);
1042                 }
1043 #endif
1044
1045                 /*
1046                  * retrieve parameters from the inner IPv6 header, and convert
1047                  * them into sockaddr structures.
1048                  * XXX: there is no guarantee that the source or destination
1049                  * addresses of the inner packet are in the same scope as
1050                  * the addresses of the icmp packet.  But there is no other
1051                  * way to determine the zone.
1052                  */
1053                 eip6 = (struct ip6_hdr *)(icmp6 + 1);
1054
1055                 bzero(&icmp6dst, sizeof(icmp6dst));
1056                 icmp6dst.sin6_len = sizeof(struct sockaddr_in6);
1057                 icmp6dst.sin6_family = AF_INET6;
1058                 if (finaldst == NULL)
1059                         icmp6dst.sin6_addr = eip6->ip6_dst;
1060                 else
1061                         icmp6dst.sin6_addr = *finaldst;
1062                 if (in6_setscope(&icmp6dst.sin6_addr, m->m_pkthdr.rcvif, NULL))
1063                         goto freeit;
1064                 bzero(&icmp6src, sizeof(icmp6src));
1065                 icmp6src.sin6_len = sizeof(struct sockaddr_in6);
1066                 icmp6src.sin6_family = AF_INET6;
1067                 icmp6src.sin6_addr = eip6->ip6_src;
1068                 if (in6_setscope(&icmp6src.sin6_addr, m->m_pkthdr.rcvif, NULL))
1069                         goto freeit;
1070                 icmp6src.sin6_flowinfo =
1071                     (eip6->ip6_flow & IPV6_FLOWLABEL_MASK);
1072
1073                 if (finaldst == NULL)
1074                         finaldst = &eip6->ip6_dst;
1075                 ip6cp.ip6c_m = m;
1076                 ip6cp.ip6c_icmp6 = icmp6;
1077                 ip6cp.ip6c_ip6 = (struct ip6_hdr *)(icmp6 + 1);
1078                 ip6cp.ip6c_off = eoff;
1079                 ip6cp.ip6c_finaldst = finaldst;
1080                 ip6cp.ip6c_src = &icmp6src;
1081                 ip6cp.ip6c_nxt = nxt;
1082
1083                 if (icmp6type == ICMP6_PACKET_TOO_BIG) {
1084                         notifymtu = ntohl(icmp6->icmp6_mtu);
1085                         ip6cp.ip6c_cmdarg = (void *)&notifymtu;
1086                         icmp6_mtudisc_update(&ip6cp, 1);        /*XXX*/
1087                 }
1088
1089                 ctlfunc = (void (*)(int, struct sockaddr *, void *))
1090                     (inet6sw[ip6_protox[nxt]].pr_ctlinput);
1091                 if (ctlfunc) {
1092                         (void) (*ctlfunc)(code, (struct sockaddr *)&icmp6dst,
1093                             &ip6cp);
1094                 }
1095         }
1096         *mp = m;
1097         return (0);
1098
1099   freeit:
1100         m_freem(m);
1101         return (-1);
1102 }
1103
1104 void
1105 icmp6_mtudisc_update(struct ip6ctlparam *ip6cp, int validated)
1106 {
1107         struct in6_addr *dst = ip6cp->ip6c_finaldst;
1108         struct icmp6_hdr *icmp6 = ip6cp->ip6c_icmp6;
1109         struct mbuf *m = ip6cp->ip6c_m; /* will be necessary for scope issue */
1110         u_int mtu = ntohl(icmp6->icmp6_mtu);
1111         struct in_conninfo inc;
1112
1113 #if 0
1114         /*
1115          * RFC2460 section 5, last paragraph.
1116          * even though minimum link MTU for IPv6 is IPV6_MMTU,
1117          * we may see ICMPv6 too big with mtu < IPV6_MMTU
1118          * due to packet translator in the middle.
1119          * see ip6_output() and ip6_getpmtu() "alwaysfrag" case for
1120          * special handling.
1121          */
1122         if (mtu < IPV6_MMTU)
1123                 return;
1124 #endif
1125
1126         /*
1127          * we reject ICMPv6 too big with abnormally small value.
1128          * XXX what is the good definition of "abnormally small"?
1129          */
1130         if (mtu < sizeof(struct ip6_hdr) + sizeof(struct ip6_frag) + 8)
1131                 return;
1132
1133         if (!validated)
1134                 return;
1135
1136         /*
1137          * In case the suggested mtu is less than IPV6_MMTU, we
1138          * only need to remember that it was for above mentioned
1139          * "alwaysfrag" case.
1140          * Try to be as close to the spec as possible.
1141          */
1142         if (mtu < IPV6_MMTU)
1143                 mtu = IPV6_MMTU - 8;
1144
1145         bzero(&inc, sizeof(inc));
1146         inc.inc_fibnum = M_GETFIB(m);
1147         inc.inc_flags |= INC_ISIPV6;
1148         inc.inc6_faddr = *dst;
1149         if (in6_setscope(&inc.inc6_faddr, m->m_pkthdr.rcvif, NULL))
1150                 return;
1151
1152         if (mtu < tcp_maxmtu6(&inc, NULL)) {
1153                 tcp_hc_updatemtu(&inc, mtu);
1154                 ICMP6STAT_INC(icp6s_pmtuchg);
1155         }
1156 }
1157
1158 /*
1159  * Process a Node Information Query packet, based on
1160  * draft-ietf-ipngwg-icmp-name-lookups-07.
1161  *
1162  * Spec incompatibilities:
1163  * - IPv6 Subject address handling
1164  * - IPv4 Subject address handling support missing
1165  * - Proxy reply (answer even if it's not for me)
1166  * - joins NI group address at in6_ifattach() time only, does not cope
1167  *   with hostname changes by sethostname(3)
1168  */
1169 static struct mbuf *
1170 ni6_input(struct mbuf *m, int off)
1171 {
1172         struct icmp6_nodeinfo *ni6, *nni6;
1173         struct mbuf *n = NULL;
1174         struct prison *pr;
1175         u_int16_t qtype;
1176         int subjlen;
1177         int replylen = sizeof(struct ip6_hdr) + sizeof(struct icmp6_nodeinfo);
1178         struct ni_reply_fqdn *fqdn;
1179         int addrs;              /* for NI_QTYPE_NODEADDR */
1180         struct ifnet *ifp = NULL; /* for NI_QTYPE_NODEADDR */
1181         struct in6_addr in6_subj; /* subject address */
1182         struct ip6_hdr *ip6;
1183         int oldfqdn = 0;        /* if 1, return pascal string (03 draft) */
1184         char *subj = NULL;
1185         struct in6_ifaddr *ia6 = NULL;
1186
1187         ip6 = mtod(m, struct ip6_hdr *);
1188 #ifndef PULLDOWN_TEST
1189         ni6 = (struct icmp6_nodeinfo *)(mtod(m, caddr_t) + off);
1190 #else
1191         IP6_EXTHDR_GET(ni6, struct icmp6_nodeinfo *, m, off, sizeof(*ni6));
1192         if (ni6 == NULL) {
1193                 /* m is already reclaimed */
1194                 return (NULL);
1195         }
1196 #endif
1197
1198         /*
1199          * Validate IPv6 source address.
1200          * The default configuration MUST be to refuse answering queries from
1201          * global-scope addresses according to RFC4602.
1202          * Notes:
1203          *  - it's not very clear what "refuse" means; this implementation
1204          *    simply drops it.
1205          *  - it's not very easy to identify global-scope (unicast) addresses
1206          *    since there are many prefixes for them.  It should be safer
1207          *    and in practice sufficient to check "all" but loopback and
1208          *    link-local (note that site-local unicast was deprecated and
1209          *    ULA is defined as global scope-wise)
1210          */
1211         if ((V_icmp6_nodeinfo & ICMP6_NODEINFO_GLOBALOK) == 0 &&
1212             !IN6_IS_ADDR_LOOPBACK(&ip6->ip6_src) &&
1213             !IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_src))
1214                 goto bad;
1215
1216         /*
1217          * Validate IPv6 destination address.
1218          *
1219          * The Responder must discard the Query without further processing
1220          * unless it is one of the Responder's unicast or anycast addresses, or
1221          * a link-local scope multicast address which the Responder has joined.
1222          * [RFC4602, Section 5.]
1223          */
1224         if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
1225                 if (!IN6_IS_ADDR_MC_LINKLOCAL(&ip6->ip6_dst))
1226                         goto bad;
1227                 /* else it's a link-local multicast, fine */
1228         } else {                /* unicast or anycast */
1229                 ia6 = in6ifa_ifwithaddr(&ip6->ip6_dst, 0 /* XXX */);
1230                 if (ia6 == NULL)
1231                         goto bad; /* XXX impossible */
1232
1233                 if ((ia6->ia6_flags & IN6_IFF_TEMPORARY) &&
1234                     !(V_icmp6_nodeinfo & ICMP6_NODEINFO_TMPADDROK)) {
1235                         ifa_free(&ia6->ia_ifa);
1236                         nd6log((LOG_DEBUG, "ni6_input: ignore node info to "
1237                                 "a temporary address in %s:%d",
1238                                __FILE__, __LINE__));
1239                         goto bad;
1240                 }
1241                 ifa_free(&ia6->ia_ifa);
1242         }
1243
1244         /* validate query Subject field. */
1245         qtype = ntohs(ni6->ni_qtype);
1246         subjlen = m->m_pkthdr.len - off - sizeof(struct icmp6_nodeinfo);
1247         switch (qtype) {
1248         case NI_QTYPE_NOOP:
1249         case NI_QTYPE_SUPTYPES:
1250                 /* 07 draft */
1251                 if (ni6->ni_code == ICMP6_NI_SUBJ_FQDN && subjlen == 0)
1252                         break;
1253                 /* FALLTHROUGH */
1254         case NI_QTYPE_FQDN:
1255         case NI_QTYPE_NODEADDR:
1256         case NI_QTYPE_IPV4ADDR:
1257                 switch (ni6->ni_code) {
1258                 case ICMP6_NI_SUBJ_IPV6:
1259 #if ICMP6_NI_SUBJ_IPV6 != 0
1260                 case 0:
1261 #endif
1262                         /*
1263                          * backward compatibility - try to accept 03 draft
1264                          * format, where no Subject is present.
1265                          */
1266                         if (qtype == NI_QTYPE_FQDN && ni6->ni_code == 0 &&
1267                             subjlen == 0) {
1268                                 oldfqdn++;
1269                                 break;
1270                         }
1271 #if ICMP6_NI_SUBJ_IPV6 != 0
1272                         if (ni6->ni_code != ICMP6_NI_SUBJ_IPV6)
1273                                 goto bad;
1274 #endif
1275
1276                         if (subjlen != sizeof(struct in6_addr))
1277                                 goto bad;
1278
1279                         /*
1280                          * Validate Subject address.
1281                          *
1282                          * Not sure what exactly "address belongs to the node"
1283                          * means in the spec, is it just unicast, or what?
1284                          *
1285                          * At this moment we consider Subject address as
1286                          * "belong to the node" if the Subject address equals
1287                          * to the IPv6 destination address; validation for
1288                          * IPv6 destination address should have done enough
1289                          * check for us.
1290                          *
1291                          * We do not do proxy at this moment.
1292                          */
1293                         /* m_pulldown instead of copy? */
1294                         m_copydata(m, off + sizeof(struct icmp6_nodeinfo),
1295                             subjlen, (caddr_t)&in6_subj);
1296                         if (in6_setscope(&in6_subj, m->m_pkthdr.rcvif, NULL))
1297                                 goto bad;
1298
1299                         subj = (char *)&in6_subj;
1300                         if (IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &in6_subj))
1301                                 break;
1302
1303                         /*
1304                          * XXX if we are to allow other cases, we should really
1305                          * be careful about scope here.
1306                          * basically, we should disallow queries toward IPv6
1307                          * destination X with subject Y,
1308                          * if scope(X) > scope(Y).
1309                          * if we allow scope(X) > scope(Y), it will result in
1310                          * information leakage across scope boundary.
1311                          */
1312                         goto bad;
1313
1314                 case ICMP6_NI_SUBJ_FQDN:
1315                         /*
1316                          * Validate Subject name with gethostname(3).
1317                          *
1318                          * The behavior may need some debate, since:
1319                          * - we are not sure if the node has FQDN as
1320                          *   hostname (returned by gethostname(3)).
1321                          * - the code does wildcard match for truncated names.
1322                          *   however, we are not sure if we want to perform
1323                          *   wildcard match, if gethostname(3) side has
1324                          *   truncated hostname.
1325                          */
1326                         pr = curthread->td_ucred->cr_prison;
1327                         mtx_lock(&pr->pr_mtx);
1328                         n = ni6_nametodns(pr->pr_hostname,
1329                             strlen(pr->pr_hostname), 0);
1330                         mtx_unlock(&pr->pr_mtx);
1331                         if (!n || n->m_next || n->m_len == 0)
1332                                 goto bad;
1333                         IP6_EXTHDR_GET(subj, char *, m,
1334                             off + sizeof(struct icmp6_nodeinfo), subjlen);
1335                         if (subj == NULL)
1336                                 goto bad;
1337                         if (!ni6_dnsmatch(subj, subjlen, mtod(n, const char *),
1338                             n->m_len)) {
1339                                 goto bad;
1340                         }
1341                         m_freem(n);
1342                         n = NULL;
1343                         break;
1344
1345                 case ICMP6_NI_SUBJ_IPV4:        /* XXX: to be implemented? */
1346                 default:
1347                         goto bad;
1348                 }
1349                 break;
1350         }
1351
1352         /* refuse based on configuration.  XXX ICMP6_NI_REFUSED? */
1353         switch (qtype) {
1354         case NI_QTYPE_FQDN:
1355                 if ((V_icmp6_nodeinfo & ICMP6_NODEINFO_FQDNOK) == 0)
1356                         goto bad;
1357                 break;
1358         case NI_QTYPE_NODEADDR:
1359         case NI_QTYPE_IPV4ADDR:
1360                 if ((V_icmp6_nodeinfo & ICMP6_NODEINFO_NODEADDROK) == 0)
1361                         goto bad;
1362                 break;
1363         }
1364
1365         /* guess reply length */
1366         switch (qtype) {
1367         case NI_QTYPE_NOOP:
1368                 break;          /* no reply data */
1369         case NI_QTYPE_SUPTYPES:
1370                 replylen += sizeof(u_int32_t);
1371                 break;
1372         case NI_QTYPE_FQDN:
1373                 /* XXX will append an mbuf */
1374                 replylen += offsetof(struct ni_reply_fqdn, ni_fqdn_namelen);
1375                 break;
1376         case NI_QTYPE_NODEADDR:
1377                 addrs = ni6_addrs(ni6, m, &ifp, (struct in6_addr *)subj);
1378                 if ((replylen += addrs * (sizeof(struct in6_addr) +
1379                     sizeof(u_int32_t))) > MCLBYTES)
1380                         replylen = MCLBYTES; /* XXX: will truncate pkt later */
1381                 break;
1382         case NI_QTYPE_IPV4ADDR:
1383                 /* unsupported - should respond with unknown Qtype? */
1384                 break;
1385         default:
1386                 /*
1387                  * XXX: We must return a reply with the ICMP6 code
1388                  * `unknown Qtype' in this case.  However we regard the case
1389                  * as an FQDN query for backward compatibility.
1390                  * Older versions set a random value to this field,
1391                  * so it rarely varies in the defined qtypes.
1392                  * But the mechanism is not reliable...
1393                  * maybe we should obsolete older versions.
1394                  */
1395                 qtype = NI_QTYPE_FQDN;
1396                 /* XXX will append an mbuf */
1397                 replylen += offsetof(struct ni_reply_fqdn, ni_fqdn_namelen);
1398                 oldfqdn++;
1399                 break;
1400         }
1401
1402         /* Allocate an mbuf to reply. */
1403         if (replylen > MCLBYTES) {
1404                 /*
1405                  * XXX: should we try to allocate more? But MCLBYTES
1406                  * is probably much larger than IPV6_MMTU...
1407                  */
1408                 goto bad;
1409         }
1410         if (replylen > MHLEN)
1411                 n = m_getcl(M_NOWAIT, m->m_type, M_PKTHDR);
1412         else
1413                 n = m_gethdr(M_NOWAIT, m->m_type);
1414         if (n == NULL) {
1415                 m_freem(m);
1416                 return (NULL);
1417         }
1418         m_move_pkthdr(n, m); /* just for recvif and FIB */
1419         n->m_pkthdr.len = n->m_len = replylen;
1420
1421         /* copy mbuf header and IPv6 + Node Information base headers */
1422         bcopy(mtod(m, caddr_t), mtod(n, caddr_t), sizeof(struct ip6_hdr));
1423         nni6 = (struct icmp6_nodeinfo *)(mtod(n, struct ip6_hdr *) + 1);
1424         bcopy((caddr_t)ni6, (caddr_t)nni6, sizeof(struct icmp6_nodeinfo));
1425
1426         /* qtype dependent procedure */
1427         switch (qtype) {
1428         case NI_QTYPE_NOOP:
1429                 nni6->ni_code = ICMP6_NI_SUCCESS;
1430                 nni6->ni_flags = 0;
1431                 break;
1432         case NI_QTYPE_SUPTYPES:
1433         {
1434                 u_int32_t v;
1435                 nni6->ni_code = ICMP6_NI_SUCCESS;
1436                 nni6->ni_flags = htons(0x0000); /* raw bitmap */
1437                 /* supports NOOP, SUPTYPES, FQDN, and NODEADDR */
1438                 v = (u_int32_t)htonl(0x0000000f);
1439                 bcopy(&v, nni6 + 1, sizeof(u_int32_t));
1440                 break;
1441         }
1442         case NI_QTYPE_FQDN:
1443                 nni6->ni_code = ICMP6_NI_SUCCESS;
1444                 fqdn = (struct ni_reply_fqdn *)(mtod(n, caddr_t) +
1445                     sizeof(struct ip6_hdr) + sizeof(struct icmp6_nodeinfo));
1446                 nni6->ni_flags = 0; /* XXX: meaningless TTL */
1447                 fqdn->ni_fqdn_ttl = 0;  /* ditto. */
1448                 /*
1449                  * XXX do we really have FQDN in hostname?
1450                  */
1451                 pr = curthread->td_ucred->cr_prison;
1452                 mtx_lock(&pr->pr_mtx);
1453                 n->m_next = ni6_nametodns(pr->pr_hostname,
1454                     strlen(pr->pr_hostname), oldfqdn);
1455                 mtx_unlock(&pr->pr_mtx);
1456                 if (n->m_next == NULL)
1457                         goto bad;
1458                 /* XXX we assume that n->m_next is not a chain */
1459                 if (n->m_next->m_next != NULL)
1460                         goto bad;
1461                 n->m_pkthdr.len += n->m_next->m_len;
1462                 break;
1463         case NI_QTYPE_NODEADDR:
1464         {
1465                 int lenlim, copied;
1466
1467                 nni6->ni_code = ICMP6_NI_SUCCESS;
1468                 n->m_pkthdr.len = n->m_len =
1469                     sizeof(struct ip6_hdr) + sizeof(struct icmp6_nodeinfo);
1470                 lenlim = M_TRAILINGSPACE(n);
1471                 copied = ni6_store_addrs(ni6, nni6, ifp, lenlim);
1472                 /* XXX: reset mbuf length */
1473                 n->m_pkthdr.len = n->m_len = sizeof(struct ip6_hdr) +
1474                     sizeof(struct icmp6_nodeinfo) + copied;
1475                 break;
1476         }
1477         default:
1478                 break;          /* XXX impossible! */
1479         }
1480
1481         nni6->ni_type = ICMP6_NI_REPLY;
1482         m_freem(m);
1483         return (n);
1484
1485   bad:
1486         m_freem(m);
1487         if (n)
1488                 m_freem(n);
1489         return (NULL);
1490 }
1491
1492 /*
1493  * make a mbuf with DNS-encoded string.  no compression support.
1494  *
1495  * XXX names with less than 2 dots (like "foo" or "foo.section") will be
1496  * treated as truncated name (two \0 at the end).  this is a wild guess.
1497  *
1498  * old - return pascal string if non-zero
1499  */
1500 static struct mbuf *
1501 ni6_nametodns(const char *name, int namelen, int old)
1502 {
1503         struct mbuf *m;
1504         char *cp, *ep;
1505         const char *p, *q;
1506         int i, len, nterm;
1507
1508         if (old)
1509                 len = namelen + 1;
1510         else
1511                 len = MCLBYTES;
1512
1513         /* Because MAXHOSTNAMELEN is usually 256, we use cluster mbuf. */
1514         if (len > MLEN)
1515                 m = m_getcl(M_NOWAIT, MT_DATA, 0);
1516         else
1517                 m = m_get(M_NOWAIT, MT_DATA);
1518         if (m == NULL)
1519                 goto fail;
1520
1521         if (old) {
1522                 m->m_len = len;
1523                 *mtod(m, char *) = namelen;
1524                 bcopy(name, mtod(m, char *) + 1, namelen);
1525                 return m;
1526         } else {
1527                 m->m_len = 0;
1528                 cp = mtod(m, char *);
1529                 ep = mtod(m, char *) + M_TRAILINGSPACE(m);
1530
1531                 /* if not certain about my name, return empty buffer */
1532                 if (namelen == 0)
1533                         return m;
1534
1535                 /*
1536                  * guess if it looks like shortened hostname, or FQDN.
1537                  * shortened hostname needs two trailing "\0".
1538                  */
1539                 i = 0;
1540                 for (p = name; p < name + namelen; p++) {
1541                         if (*p && *p == '.')
1542                                 i++;
1543                 }
1544                 if (i < 2)
1545                         nterm = 2;
1546                 else
1547                         nterm = 1;
1548
1549                 p = name;
1550                 while (cp < ep && p < name + namelen) {
1551                         i = 0;
1552                         for (q = p; q < name + namelen && *q && *q != '.'; q++)
1553                                 i++;
1554                         /* result does not fit into mbuf */
1555                         if (cp + i + 1 >= ep)
1556                                 goto fail;
1557                         /*
1558                          * DNS label length restriction, RFC1035 page 8.
1559                          * "i == 0" case is included here to avoid returning
1560                          * 0-length label on "foo..bar".
1561                          */
1562                         if (i <= 0 || i >= 64)
1563                                 goto fail;
1564                         *cp++ = i;
1565                         bcopy(p, cp, i);
1566                         cp += i;
1567                         p = q;
1568                         if (p < name + namelen && *p == '.')
1569                                 p++;
1570                 }
1571                 /* termination */
1572                 if (cp + nterm >= ep)
1573                         goto fail;
1574                 while (nterm-- > 0)
1575                         *cp++ = '\0';
1576                 m->m_len = cp - mtod(m, char *);
1577                 return m;
1578         }
1579
1580         panic("should not reach here");
1581         /* NOTREACHED */
1582
1583  fail:
1584         if (m)
1585                 m_freem(m);
1586         return NULL;
1587 }
1588
1589 /*
1590  * check if two DNS-encoded string matches.  takes care of truncated
1591  * form (with \0\0 at the end).  no compression support.
1592  * XXX upper/lowercase match (see RFC2065)
1593  */
1594 static int
1595 ni6_dnsmatch(const char *a, int alen, const char *b, int blen)
1596 {
1597         const char *a0, *b0;
1598         int l;
1599
1600         /* simplest case - need validation? */
1601         if (alen == blen && bcmp(a, b, alen) == 0)
1602                 return 1;
1603
1604         a0 = a;
1605         b0 = b;
1606
1607         /* termination is mandatory */
1608         if (alen < 2 || blen < 2)
1609                 return 0;
1610         if (a0[alen - 1] != '\0' || b0[blen - 1] != '\0')
1611                 return 0;
1612         alen--;
1613         blen--;
1614
1615         while (a - a0 < alen && b - b0 < blen) {
1616                 if (a - a0 + 1 > alen || b - b0 + 1 > blen)
1617                         return 0;
1618
1619                 if ((signed char)a[0] < 0 || (signed char)b[0] < 0)
1620                         return 0;
1621                 /* we don't support compression yet */
1622                 if (a[0] >= 64 || b[0] >= 64)
1623                         return 0;
1624
1625                 /* truncated case */
1626                 if (a[0] == 0 && a - a0 == alen - 1)
1627                         return 1;
1628                 if (b[0] == 0 && b - b0 == blen - 1)
1629                         return 1;
1630                 if (a[0] == 0 || b[0] == 0)
1631                         return 0;
1632
1633                 if (a[0] != b[0])
1634                         return 0;
1635                 l = a[0];
1636                 if (a - a0 + 1 + l > alen || b - b0 + 1 + l > blen)
1637                         return 0;
1638                 if (bcmp(a + 1, b + 1, l) != 0)
1639                         return 0;
1640
1641                 a += 1 + l;
1642                 b += 1 + l;
1643         }
1644
1645         if (a - a0 == alen && b - b0 == blen)
1646                 return 1;
1647         else
1648                 return 0;
1649 }
1650
1651 /*
1652  * calculate the number of addresses to be returned in the node info reply.
1653  */
1654 static int
1655 ni6_addrs(struct icmp6_nodeinfo *ni6, struct mbuf *m, struct ifnet **ifpp,
1656     struct in6_addr *subj)
1657 {
1658         struct ifnet *ifp;
1659         struct in6_ifaddr *ifa6;
1660         struct ifaddr *ifa;
1661         int addrs = 0, addrsofif, iffound = 0;
1662         int niflags = ni6->ni_flags;
1663
1664         if ((niflags & NI_NODEADDR_FLAG_ALL) == 0) {
1665                 switch (ni6->ni_code) {
1666                 case ICMP6_NI_SUBJ_IPV6:
1667                         if (subj == NULL) /* must be impossible... */
1668                                 return (0);
1669                         break;
1670                 default:
1671                         /*
1672                          * XXX: we only support IPv6 subject address for
1673                          * this Qtype.
1674                          */
1675                         return (0);
1676                 }
1677         }
1678
1679         IFNET_RLOCK_NOSLEEP();
1680         CK_STAILQ_FOREACH(ifp, &V_ifnet, if_link) {
1681                 addrsofif = 0;
1682                 IF_ADDR_RLOCK(ifp);
1683                 CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
1684                         if (ifa->ifa_addr->sa_family != AF_INET6)
1685                                 continue;
1686                         ifa6 = (struct in6_ifaddr *)ifa;
1687
1688                         if ((niflags & NI_NODEADDR_FLAG_ALL) == 0 &&
1689                             IN6_ARE_ADDR_EQUAL(subj, &ifa6->ia_addr.sin6_addr))
1690                                 iffound = 1;
1691
1692                         /*
1693                          * IPv4-mapped addresses can only be returned by a
1694                          * Node Information proxy, since they represent
1695                          * addresses of IPv4-only nodes, which perforce do
1696                          * not implement this protocol.
1697                          * [icmp-name-lookups-07, Section 5.4]
1698                          * So we don't support NI_NODEADDR_FLAG_COMPAT in
1699                          * this function at this moment.
1700                          */
1701
1702                         /* What do we have to do about ::1? */
1703                         switch (in6_addrscope(&ifa6->ia_addr.sin6_addr)) {
1704                         case IPV6_ADDR_SCOPE_LINKLOCAL:
1705                                 if ((niflags & NI_NODEADDR_FLAG_LINKLOCAL) == 0)
1706                                         continue;
1707                                 break;
1708                         case IPV6_ADDR_SCOPE_SITELOCAL:
1709                                 if ((niflags & NI_NODEADDR_FLAG_SITELOCAL) == 0)
1710                                         continue;
1711                                 break;
1712                         case IPV6_ADDR_SCOPE_GLOBAL:
1713                                 if ((niflags & NI_NODEADDR_FLAG_GLOBAL) == 0)
1714                                         continue;
1715                                 break;
1716                         default:
1717                                 continue;
1718                         }
1719
1720                         /*
1721                          * check if anycast is okay.
1722                          * XXX: just experimental.  not in the spec.
1723                          */
1724                         if ((ifa6->ia6_flags & IN6_IFF_ANYCAST) != 0 &&
1725                             (niflags & NI_NODEADDR_FLAG_ANYCAST) == 0)
1726                                 continue; /* we need only unicast addresses */
1727                         if ((ifa6->ia6_flags & IN6_IFF_TEMPORARY) != 0 &&
1728                             (V_icmp6_nodeinfo & ICMP6_NODEINFO_TMPADDROK) == 0) {
1729                                 continue;
1730                         }
1731                         addrsofif++; /* count the address */
1732                 }
1733                 IF_ADDR_RUNLOCK(ifp);
1734                 if (iffound) {
1735                         *ifpp = ifp;
1736                         IFNET_RUNLOCK_NOSLEEP();
1737                         return (addrsofif);
1738                 }
1739
1740                 addrs += addrsofif;
1741         }
1742         IFNET_RUNLOCK_NOSLEEP();
1743
1744         return (addrs);
1745 }
1746
1747 static int
1748 ni6_store_addrs(struct icmp6_nodeinfo *ni6, struct icmp6_nodeinfo *nni6,
1749     struct ifnet *ifp0, int resid)
1750 {
1751         struct ifnet *ifp;
1752         struct in6_ifaddr *ifa6;
1753         struct ifaddr *ifa;
1754         struct ifnet *ifp_dep = NULL;
1755         int copied = 0, allow_deprecated = 0;
1756         u_char *cp = (u_char *)(nni6 + 1);
1757         int niflags = ni6->ni_flags;
1758         u_int32_t ltime;
1759
1760         if (ifp0 == NULL && !(niflags & NI_NODEADDR_FLAG_ALL))
1761                 return (0);     /* needless to copy */
1762
1763         IFNET_RLOCK_NOSLEEP();
1764         ifp = ifp0 ? ifp0 : CK_STAILQ_FIRST(&V_ifnet);
1765   again:
1766
1767         for (; ifp; ifp = CK_STAILQ_NEXT(ifp, if_link)) {
1768                 IF_ADDR_RLOCK(ifp);
1769                 CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
1770                         if (ifa->ifa_addr->sa_family != AF_INET6)
1771                                 continue;
1772                         ifa6 = (struct in6_ifaddr *)ifa;
1773
1774                         if ((ifa6->ia6_flags & IN6_IFF_DEPRECATED) != 0 &&
1775                             allow_deprecated == 0) {
1776                                 /*
1777                                  * prefererred address should be put before
1778                                  * deprecated addresses.
1779                                  */
1780
1781                                 /* record the interface for later search */
1782                                 if (ifp_dep == NULL)
1783                                         ifp_dep = ifp;
1784
1785                                 continue;
1786                         } else if ((ifa6->ia6_flags & IN6_IFF_DEPRECATED) == 0 &&
1787                             allow_deprecated != 0)
1788                                 continue; /* we now collect deprecated addrs */
1789
1790                         /* What do we have to do about ::1? */
1791                         switch (in6_addrscope(&ifa6->ia_addr.sin6_addr)) {
1792                         case IPV6_ADDR_SCOPE_LINKLOCAL:
1793                                 if ((niflags & NI_NODEADDR_FLAG_LINKLOCAL) == 0)
1794                                         continue;
1795                                 break;
1796                         case IPV6_ADDR_SCOPE_SITELOCAL:
1797                                 if ((niflags & NI_NODEADDR_FLAG_SITELOCAL) == 0)
1798                                         continue;
1799                                 break;
1800                         case IPV6_ADDR_SCOPE_GLOBAL:
1801                                 if ((niflags & NI_NODEADDR_FLAG_GLOBAL) == 0)
1802                                         continue;
1803                                 break;
1804                         default:
1805                                 continue;
1806                         }
1807
1808                         /*
1809                          * check if anycast is okay.
1810                          * XXX: just experimental.  not in the spec.
1811                          */
1812                         if ((ifa6->ia6_flags & IN6_IFF_ANYCAST) != 0 &&
1813                             (niflags & NI_NODEADDR_FLAG_ANYCAST) == 0)
1814                                 continue;
1815                         if ((ifa6->ia6_flags & IN6_IFF_TEMPORARY) != 0 &&
1816                             (V_icmp6_nodeinfo & ICMP6_NODEINFO_TMPADDROK) == 0) {
1817                                 continue;
1818                         }
1819
1820                         /* now we can copy the address */
1821                         if (resid < sizeof(struct in6_addr) +
1822                             sizeof(u_int32_t)) {
1823                                 IF_ADDR_RUNLOCK(ifp);
1824                                 /*
1825                                  * We give up much more copy.
1826                                  * Set the truncate flag and return.
1827                                  */
1828                                 nni6->ni_flags |= NI_NODEADDR_FLAG_TRUNCATE;
1829                                 IFNET_RUNLOCK_NOSLEEP();
1830                                 return (copied);
1831                         }
1832
1833                         /*
1834                          * Set the TTL of the address.
1835                          * The TTL value should be one of the following
1836                          * according to the specification:
1837                          *
1838                          * 1. The remaining lifetime of a DHCP lease on the
1839                          *    address, or
1840                          * 2. The remaining Valid Lifetime of a prefix from
1841                          *    which the address was derived through Stateless
1842                          *    Autoconfiguration.
1843                          *
1844                          * Note that we currently do not support stateful
1845                          * address configuration by DHCPv6, so the former
1846                          * case can't happen.
1847                          */
1848                         if (ifa6->ia6_lifetime.ia6t_expire == 0)
1849                                 ltime = ND6_INFINITE_LIFETIME;
1850                         else {
1851                                 if (ifa6->ia6_lifetime.ia6t_expire >
1852                                     time_uptime)
1853                                         ltime = htonl(ifa6->ia6_lifetime.ia6t_expire - time_uptime);
1854                                 else
1855                                         ltime = 0;
1856                         }
1857
1858                         bcopy(&ltime, cp, sizeof(u_int32_t));
1859                         cp += sizeof(u_int32_t);
1860
1861                         /* copy the address itself */
1862                         bcopy(&ifa6->ia_addr.sin6_addr, cp,
1863                             sizeof(struct in6_addr));
1864                         in6_clearscope((struct in6_addr *)cp); /* XXX */
1865                         cp += sizeof(struct in6_addr);
1866
1867                         resid -= (sizeof(struct in6_addr) + sizeof(u_int32_t));
1868                         copied += (sizeof(struct in6_addr) + sizeof(u_int32_t));
1869                 }
1870                 IF_ADDR_RUNLOCK(ifp);
1871                 if (ifp0)       /* we need search only on the specified IF */
1872                         break;
1873         }
1874
1875         if (allow_deprecated == 0 && ifp_dep != NULL) {
1876                 ifp = ifp_dep;
1877                 allow_deprecated = 1;
1878
1879                 goto again;
1880         }
1881
1882         IFNET_RUNLOCK_NOSLEEP();
1883
1884         return (copied);
1885 }
1886
1887 /*
1888  * XXX almost dup'ed code with rip6_input.
1889  */
1890 static int
1891 icmp6_rip6_input(struct mbuf **mp, int off)
1892 {
1893         struct mbuf *m = *mp;
1894         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
1895         struct inpcb *in6p;
1896         struct inpcb *last = NULL;
1897         struct sockaddr_in6 fromsa;
1898         struct icmp6_hdr *icmp6;
1899         struct epoch_tracker et;
1900         struct mbuf *opts = NULL;
1901
1902 #ifndef PULLDOWN_TEST
1903         /* this is assumed to be safe. */
1904         icmp6 = (struct icmp6_hdr *)((caddr_t)ip6 + off);
1905 #else
1906         IP6_EXTHDR_GET(icmp6, struct icmp6_hdr *, m, off, sizeof(*icmp6));
1907         if (icmp6 == NULL) {
1908                 /* m is already reclaimed */
1909                 return (IPPROTO_DONE);
1910         }
1911 #endif
1912
1913         /*
1914          * XXX: the address may have embedded scope zone ID, which should be
1915          * hidden from applications.
1916          */
1917         bzero(&fromsa, sizeof(fromsa));
1918         fromsa.sin6_family = AF_INET6;
1919         fromsa.sin6_len = sizeof(struct sockaddr_in6);
1920         fromsa.sin6_addr = ip6->ip6_src;
1921         if (sa6_recoverscope(&fromsa)) {
1922                 m_freem(m);
1923                 return (IPPROTO_DONE);
1924         }
1925
1926         INP_INFO_RLOCK_ET(&V_ripcbinfo, et);
1927         CK_LIST_FOREACH(in6p, &V_ripcb, inp_list) {
1928                 if ((in6p->inp_vflag & INP_IPV6) == 0)
1929                         continue;
1930                 if (in6p->inp_ip_p != IPPROTO_ICMPV6)
1931                         continue;
1932                 if (!IN6_IS_ADDR_UNSPECIFIED(&in6p->in6p_laddr) &&
1933                    !IN6_ARE_ADDR_EQUAL(&in6p->in6p_laddr, &ip6->ip6_dst))
1934                         continue;
1935                 if (!IN6_IS_ADDR_UNSPECIFIED(&in6p->in6p_faddr) &&
1936                    !IN6_ARE_ADDR_EQUAL(&in6p->in6p_faddr, &ip6->ip6_src))
1937                         continue;
1938                 INP_RLOCK(in6p);
1939                 if (ICMP6_FILTER_WILLBLOCK(icmp6->icmp6_type,
1940                     in6p->in6p_icmp6filt)) {
1941                         INP_RUNLOCK(in6p);
1942                         continue;
1943                 }
1944                 if (last != NULL) {
1945                         struct  mbuf *n = NULL;
1946
1947                         /*
1948                          * Recent network drivers tend to allocate a single
1949                          * mbuf cluster, rather than to make a couple of
1950                          * mbufs without clusters.  Also, since the IPv6 code
1951                          * path tries to avoid m_pullup(), it is highly
1952                          * probable that we still have an mbuf cluster here
1953                          * even though the necessary length can be stored in an
1954                          * mbuf's internal buffer.
1955                          * Meanwhile, the default size of the receive socket
1956                          * buffer for raw sockets is not so large.  This means
1957                          * the possibility of packet loss is relatively higher
1958                          * than before.  To avoid this scenario, we copy the
1959                          * received data to a separate mbuf that does not use
1960                          * a cluster, if possible.
1961                          * XXX: it is better to copy the data after stripping
1962                          * intermediate headers.
1963                          */
1964                         if ((m->m_flags & M_EXT) && m->m_next == NULL &&
1965                             m->m_len <= MHLEN) {
1966                                 n = m_get(M_NOWAIT, m->m_type);
1967                                 if (n != NULL) {
1968                                         if (m_dup_pkthdr(n, m, M_NOWAIT)) {
1969                                                 bcopy(m->m_data, n->m_data,
1970                                                       m->m_len);
1971                                                 n->m_len = m->m_len;
1972                                         } else {
1973                                                 m_free(n);
1974                                                 n = NULL;
1975                                         }
1976                                 }
1977                         }
1978                         if (n != NULL ||
1979                             (n = m_copym(m, 0, M_COPYALL, M_NOWAIT)) != NULL) {
1980                                 if (last->inp_flags & INP_CONTROLOPTS)
1981                                         ip6_savecontrol(last, n, &opts);
1982                                 /* strip intermediate headers */
1983                                 m_adj(n, off);
1984                                 SOCKBUF_LOCK(&last->inp_socket->so_rcv);
1985                                 if (sbappendaddr_locked(
1986                                     &last->inp_socket->so_rcv,
1987                                     (struct sockaddr *)&fromsa, n, opts)
1988                                     == 0) {
1989                                         /* should notify about lost packet */
1990                                         m_freem(n);
1991                                         if (opts) {
1992                                                 m_freem(opts);
1993                                         }
1994                                         SOCKBUF_UNLOCK(
1995                                             &last->inp_socket->so_rcv);
1996                                 } else
1997                                         sorwakeup_locked(last->inp_socket);
1998                                 opts = NULL;
1999                         }
2000                         INP_RUNLOCK(last);
2001                 }
2002                 last = in6p;
2003         }
2004         INP_INFO_RUNLOCK_ET(&V_ripcbinfo, et);
2005         if (last != NULL) {
2006                 if (last->inp_flags & INP_CONTROLOPTS)
2007                         ip6_savecontrol(last, m, &opts);
2008                 /* strip intermediate headers */
2009                 m_adj(m, off);
2010
2011                 /* avoid using mbuf clusters if possible (see above) */
2012                 if ((m->m_flags & M_EXT) && m->m_next == NULL &&
2013                     m->m_len <= MHLEN) {
2014                         struct mbuf *n;
2015
2016                         n = m_get(M_NOWAIT, m->m_type);
2017                         if (n != NULL) {
2018                                 if (m_dup_pkthdr(n, m, M_NOWAIT)) {
2019                                         bcopy(m->m_data, n->m_data, m->m_len);
2020                                         n->m_len = m->m_len;
2021
2022                                         m_freem(m);
2023                                         m = n;
2024                                 } else {
2025                                         m_freem(n);
2026                                         n = NULL;
2027                                 }
2028                         }
2029                 }
2030                 SOCKBUF_LOCK(&last->inp_socket->so_rcv);
2031                 if (sbappendaddr_locked(&last->inp_socket->so_rcv,
2032                     (struct sockaddr *)&fromsa, m, opts) == 0) {
2033                         m_freem(m);
2034                         if (opts)
2035                                 m_freem(opts);
2036                         SOCKBUF_UNLOCK(&last->inp_socket->so_rcv);
2037                 } else
2038                         sorwakeup_locked(last->inp_socket);
2039                 INP_RUNLOCK(last);
2040         } else {
2041                 m_freem(m);
2042                 IP6STAT_DEC(ip6s_delivered);
2043         }
2044         return IPPROTO_DONE;
2045 }
2046
2047 /*
2048  * Reflect the ip6 packet back to the source.
2049  * OFF points to the icmp6 header, counted from the top of the mbuf.
2050  */
2051 void
2052 icmp6_reflect(struct mbuf *m, size_t off)
2053 {
2054         struct in6_addr src6, *srcp;
2055         struct ip6_hdr *ip6;
2056         struct icmp6_hdr *icmp6;
2057         struct in6_ifaddr *ia = NULL;
2058         struct ifnet *outif = NULL;
2059         int plen;
2060         int type, code, hlim;
2061
2062         /* too short to reflect */
2063         if (off < sizeof(struct ip6_hdr)) {
2064                 nd6log((LOG_DEBUG,
2065                     "sanity fail: off=%lx, sizeof(ip6)=%lx in %s:%d\n",
2066                     (u_long)off, (u_long)sizeof(struct ip6_hdr),
2067                     __FILE__, __LINE__));
2068                 goto bad;
2069         }
2070
2071         /*
2072          * If there are extra headers between IPv6 and ICMPv6, strip
2073          * off that header first.
2074          */
2075 #ifdef DIAGNOSTIC
2076         if (sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr) > MHLEN)
2077                 panic("assumption failed in icmp6_reflect");
2078 #endif
2079         if (off > sizeof(struct ip6_hdr)) {
2080                 size_t l;
2081                 struct ip6_hdr nip6;
2082
2083                 l = off - sizeof(struct ip6_hdr);
2084                 m_copydata(m, 0, sizeof(nip6), (caddr_t)&nip6);
2085                 m_adj(m, l);
2086                 l = sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr);
2087                 if (m->m_len < l) {
2088                         if ((m = m_pullup(m, l)) == NULL)
2089                                 return;
2090                 }
2091                 bcopy((caddr_t)&nip6, mtod(m, caddr_t), sizeof(nip6));
2092         } else /* off == sizeof(struct ip6_hdr) */ {
2093                 size_t l;
2094                 l = sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr);
2095                 if (m->m_len < l) {
2096                         if ((m = m_pullup(m, l)) == NULL)
2097                                 return;
2098                 }
2099         }
2100         plen = m->m_pkthdr.len - sizeof(struct ip6_hdr);
2101         ip6 = mtod(m, struct ip6_hdr *);
2102         ip6->ip6_nxt = IPPROTO_ICMPV6;
2103         icmp6 = (struct icmp6_hdr *)(ip6 + 1);
2104         type = icmp6->icmp6_type; /* keep type for statistics */
2105         code = icmp6->icmp6_code; /* ditto. */
2106         hlim = 0;
2107         srcp = NULL;
2108
2109         /*
2110          * If the incoming packet was addressed directly to us (i.e. unicast),
2111          * use dst as the src for the reply.
2112          * The IN6_IFF_NOTREADY case should be VERY rare, but is possible
2113          * (for example) when we encounter an error while forwarding procedure
2114          * destined to a duplicated address of ours.
2115          */
2116         if (!IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
2117                 ia = in6ifa_ifwithaddr(&ip6->ip6_dst, 0 /* XXX */);
2118                 if (ia != NULL && !(ia->ia6_flags &
2119                     (IN6_IFF_ANYCAST|IN6_IFF_NOTREADY))) {
2120                         src6 = ia->ia_addr.sin6_addr;
2121                         srcp = &src6;
2122
2123                         if (m->m_pkthdr.rcvif != NULL) {
2124                                 /* XXX: This may not be the outgoing interface */
2125                                 hlim = ND_IFINFO(m->m_pkthdr.rcvif)->chlim;
2126                         } else
2127                                 hlim = V_ip6_defhlim;
2128                 }
2129                 if (ia != NULL)
2130                         ifa_free(&ia->ia_ifa);
2131         }
2132
2133         if (srcp == NULL) {
2134                 int error;
2135                 struct in6_addr dst6;
2136                 uint32_t scopeid;
2137
2138                 /*
2139                  * This case matches to multicasts, our anycast, or unicasts
2140                  * that we do not own.  Select a source address based on the
2141                  * source address of the erroneous packet.
2142                  */
2143                 in6_splitscope(&ip6->ip6_src, &dst6, &scopeid);
2144                 error = in6_selectsrc_addr(M_GETFIB(m), &dst6,
2145                     scopeid, NULL, &src6, &hlim);
2146
2147                 if (error) {
2148                         char ip6buf[INET6_ADDRSTRLEN];
2149                         nd6log((LOG_DEBUG,
2150                             "icmp6_reflect: source can't be determined: "
2151                             "dst=%s, error=%d\n",
2152                             ip6_sprintf(ip6buf, &ip6->ip6_dst), error));
2153                         goto bad;
2154                 }
2155                 srcp = &src6;
2156         }
2157         /*
2158          * ip6_input() drops a packet if its src is multicast.
2159          * So, the src is never multicast.
2160          */
2161         ip6->ip6_dst = ip6->ip6_src;
2162         ip6->ip6_src = *srcp;
2163         ip6->ip6_flow = 0;
2164         ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
2165         ip6->ip6_vfc |= IPV6_VERSION;
2166         ip6->ip6_nxt = IPPROTO_ICMPV6;
2167         ip6->ip6_hlim = hlim;
2168
2169         icmp6->icmp6_cksum = 0;
2170         icmp6->icmp6_cksum = in6_cksum(m, IPPROTO_ICMPV6,
2171             sizeof(struct ip6_hdr), plen);
2172
2173         /*
2174          * XXX option handling
2175          */
2176
2177         m->m_flags &= ~(M_BCAST|M_MCAST);
2178         m->m_pkthdr.rcvif = NULL;
2179         ip6_output(m, NULL, NULL, 0, NULL, &outif, NULL);
2180         if (outif)
2181                 icmp6_ifoutstat_inc(outif, type, code);
2182
2183         return;
2184
2185  bad:
2186         m_freem(m);
2187         return;
2188 }
2189
2190 void
2191 icmp6_fasttimo(void)
2192 {
2193
2194         mld_fasttimo();
2195 }
2196
2197 void
2198 icmp6_slowtimo(void)
2199 {
2200
2201         mld_slowtimo();
2202 }
2203
2204 static const char *
2205 icmp6_redirect_diag(struct in6_addr *src6, struct in6_addr *dst6,
2206     struct in6_addr *tgt6)
2207 {
2208         static char buf[1024];
2209         char ip6bufs[INET6_ADDRSTRLEN];
2210         char ip6bufd[INET6_ADDRSTRLEN];
2211         char ip6buft[INET6_ADDRSTRLEN];
2212         snprintf(buf, sizeof(buf), "(src=%s dst=%s tgt=%s)",
2213             ip6_sprintf(ip6bufs, src6), ip6_sprintf(ip6bufd, dst6),
2214             ip6_sprintf(ip6buft, tgt6));
2215         return buf;
2216 }
2217
2218 void
2219 icmp6_redirect_input(struct mbuf *m, int off)
2220 {
2221         struct ifnet *ifp;
2222         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
2223         struct nd_redirect *nd_rd;
2224         int icmp6len = ntohs(ip6->ip6_plen);
2225         char *lladdr = NULL;
2226         int lladdrlen = 0;
2227         int is_router;
2228         int is_onlink;
2229         struct in6_addr src6 = ip6->ip6_src;
2230         struct in6_addr redtgt6;
2231         struct in6_addr reddst6;
2232         union nd_opts ndopts;
2233         char ip6buf[INET6_ADDRSTRLEN];
2234
2235         M_ASSERTPKTHDR(m);
2236         KASSERT(m->m_pkthdr.rcvif != NULL, ("%s: no rcvif", __func__));
2237
2238         ifp = m->m_pkthdr.rcvif;
2239
2240         /* XXX if we are router, we don't update route by icmp6 redirect */
2241         if (V_ip6_forwarding)
2242                 goto freeit;
2243         if (!V_icmp6_rediraccept)
2244                 goto freeit;
2245
2246         /* RFC 6980: Nodes MUST silently ignore fragments */
2247         if(m->m_flags & M_FRAGMENTED)
2248                 goto freeit;
2249
2250 #ifndef PULLDOWN_TEST
2251         IP6_EXTHDR_CHECK(m, off, icmp6len,);
2252         nd_rd = (struct nd_redirect *)((caddr_t)ip6 + off);
2253 #else
2254         IP6_EXTHDR_GET(nd_rd, struct nd_redirect *, m, off, icmp6len);
2255         if (nd_rd == NULL) {
2256                 ICMP6STAT_INC(icp6s_tooshort);
2257                 return;
2258         }
2259 #endif
2260         redtgt6 = nd_rd->nd_rd_target;
2261         reddst6 = nd_rd->nd_rd_dst;
2262
2263         if (in6_setscope(&redtgt6, m->m_pkthdr.rcvif, NULL) ||
2264             in6_setscope(&reddst6, m->m_pkthdr.rcvif, NULL)) {
2265                 goto freeit;
2266         }
2267
2268         /* validation */
2269         if (!IN6_IS_ADDR_LINKLOCAL(&src6)) {
2270                 nd6log((LOG_ERR,
2271                     "ICMP6 redirect sent from %s rejected; "
2272                     "must be from linklocal\n",
2273                     ip6_sprintf(ip6buf, &src6)));
2274                 goto bad;
2275         }
2276         if (ip6->ip6_hlim != 255) {
2277                 nd6log((LOG_ERR,
2278                     "ICMP6 redirect sent from %s rejected; "
2279                     "hlim=%d (must be 255)\n",
2280                     ip6_sprintf(ip6buf, &src6), ip6->ip6_hlim));
2281                 goto bad;
2282         }
2283     {
2284         /* ip6->ip6_src must be equal to gw for icmp6->icmp6_reddst */
2285         struct nhop6_basic nh6;
2286         struct in6_addr kdst;
2287         uint32_t scopeid;
2288
2289         in6_splitscope(&reddst6, &kdst, &scopeid);
2290         if (fib6_lookup_nh_basic(ifp->if_fib, &kdst, scopeid, 0, 0,&nh6)==0){
2291                 if ((nh6.nh_flags & NHF_GATEWAY) == 0) {
2292                         nd6log((LOG_ERR,
2293                             "ICMP6 redirect rejected; no route "
2294                             "with inet6 gateway found for redirect dst: %s\n",
2295                             icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2296                         goto bad;
2297                 }
2298
2299                 /*
2300                  * Embed scope zone id into next hop address, since
2301                  * fib6_lookup_nh_basic() returns address without embedded
2302                  * scope zone id.
2303                  */
2304                 if (in6_setscope(&nh6.nh_addr, m->m_pkthdr.rcvif, NULL))
2305                         goto freeit;
2306
2307                 if (IN6_ARE_ADDR_EQUAL(&src6, &nh6.nh_addr) == 0) {
2308                         nd6log((LOG_ERR,
2309                             "ICMP6 redirect rejected; "
2310                             "not equal to gw-for-src=%s (must be same): "
2311                             "%s\n",
2312                             ip6_sprintf(ip6buf, &nh6.nh_addr),
2313                             icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2314                         goto bad;
2315                 }
2316         } else {
2317                 nd6log((LOG_ERR,
2318                     "ICMP6 redirect rejected; "
2319                     "no route found for redirect dst: %s\n",
2320                     icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2321                 goto bad;
2322         }
2323     }
2324         if (IN6_IS_ADDR_MULTICAST(&reddst6)) {
2325                 nd6log((LOG_ERR,
2326                     "ICMP6 redirect rejected; "
2327                     "redirect dst must be unicast: %s\n",
2328                     icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2329                 goto bad;
2330         }
2331
2332         is_router = is_onlink = 0;
2333         if (IN6_IS_ADDR_LINKLOCAL(&redtgt6))
2334                 is_router = 1;  /* router case */
2335         if (bcmp(&redtgt6, &reddst6, sizeof(redtgt6)) == 0)
2336                 is_onlink = 1;  /* on-link destination case */
2337         if (!is_router && !is_onlink) {
2338                 nd6log((LOG_ERR,
2339                     "ICMP6 redirect rejected; "
2340                     "neither router case nor onlink case: %s\n",
2341                     icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2342                 goto bad;
2343         }
2344
2345         icmp6len -= sizeof(*nd_rd);
2346         nd6_option_init(nd_rd + 1, icmp6len, &ndopts);
2347         if (nd6_options(&ndopts) < 0) {
2348                 nd6log((LOG_INFO, "%s: invalid ND option, rejected: %s\n",
2349                     __func__, icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2350                 /* nd6_options have incremented stats */
2351                 goto freeit;
2352         }
2353
2354         if (ndopts.nd_opts_tgt_lladdr) {
2355                 lladdr = (char *)(ndopts.nd_opts_tgt_lladdr + 1);
2356                 lladdrlen = ndopts.nd_opts_tgt_lladdr->nd_opt_len << 3;
2357         }
2358
2359         if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
2360                 nd6log((LOG_INFO, "%s: lladdrlen mismatch for %s "
2361                     "(if %d, icmp6 packet %d): %s\n",
2362                     __func__, ip6_sprintf(ip6buf, &redtgt6),
2363                     ifp->if_addrlen, lladdrlen - 2,
2364                     icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
2365                 goto bad;
2366         }
2367
2368         /* Validation passed. */
2369
2370         /* RFC 2461 8.3 */
2371         nd6_cache_lladdr(ifp, &redtgt6, lladdr, lladdrlen, ND_REDIRECT,
2372             is_onlink ? ND_REDIRECT_ONLINK : ND_REDIRECT_ROUTER);
2373
2374         /*
2375          * Install a gateway route in the better-router case or an interface
2376          * route in the on-link-destination case.
2377          */
2378         {
2379                 struct sockaddr_in6 sdst;
2380                 struct sockaddr_in6 sgw;
2381                 struct sockaddr_in6 ssrc;
2382                 struct sockaddr *gw;
2383                 int rt_flags;
2384                 u_int fibnum;
2385
2386                 bzero(&sdst, sizeof(sdst));
2387                 bzero(&ssrc, sizeof(ssrc));
2388                 sdst.sin6_family = ssrc.sin6_family = AF_INET6;
2389                 sdst.sin6_len = ssrc.sin6_len = sizeof(struct sockaddr_in6);
2390                 bcopy(&reddst6, &sdst.sin6_addr, sizeof(struct in6_addr));
2391                 bcopy(&src6, &ssrc.sin6_addr, sizeof(struct in6_addr));
2392                 rt_flags = RTF_HOST;
2393                 if (is_router) {
2394                         bzero(&sgw, sizeof(sgw));
2395                         sgw.sin6_family = AF_INET6;
2396                         sgw.sin6_len = sizeof(struct sockaddr_in6);
2397                         bcopy(&redtgt6, &sgw.sin6_addr,
2398                                 sizeof(struct in6_addr));
2399                         gw = (struct sockaddr *)&sgw;
2400                         rt_flags |= RTF_GATEWAY;
2401                 } else
2402                         gw = ifp->if_addr->ifa_addr;
2403                 for (fibnum = 0; fibnum < rt_numfibs; fibnum++)
2404                         in6_rtredirect((struct sockaddr *)&sdst, gw,
2405                             (struct sockaddr *)NULL, rt_flags,
2406                             (struct sockaddr *)&ssrc, fibnum);
2407         }
2408         /* finally update cached route in each socket via pfctlinput */
2409     {
2410         struct sockaddr_in6 sdst;
2411
2412         bzero(&sdst, sizeof(sdst));
2413         sdst.sin6_family = AF_INET6;
2414         sdst.sin6_len = sizeof(struct sockaddr_in6);
2415         bcopy(&reddst6, &sdst.sin6_addr, sizeof(struct in6_addr));
2416         pfctlinput(PRC_REDIRECT_HOST, (struct sockaddr *)&sdst);
2417     }
2418
2419  freeit:
2420         m_freem(m);
2421         return;
2422
2423  bad:
2424         ICMP6STAT_INC(icp6s_badredirect);
2425         m_freem(m);
2426 }
2427
2428 void
2429 icmp6_redirect_output(struct mbuf *m0, struct rtentry *rt)
2430 {
2431         struct ifnet *ifp;      /* my outgoing interface */
2432         struct in6_addr *ifp_ll6;
2433         struct in6_addr *router_ll6;
2434         struct ip6_hdr *sip6;   /* m0 as struct ip6_hdr */
2435         struct mbuf *m = NULL;  /* newly allocated one */
2436         struct m_tag *mtag;
2437         struct ip6_hdr *ip6;    /* m as struct ip6_hdr */
2438         struct nd_redirect *nd_rd;
2439         struct llentry *ln = NULL;
2440         size_t maxlen;
2441         u_char *p;
2442         struct ifnet *outif = NULL;
2443         struct sockaddr_in6 src_sa;
2444
2445         icmp6_errcount(ND_REDIRECT, 0);
2446
2447         /* if we are not router, we don't send icmp6 redirect */
2448         if (!V_ip6_forwarding)
2449                 goto fail;
2450
2451         /* sanity check */
2452         if (!m0 || !rt || !(rt->rt_flags & RTF_UP) || !(ifp = rt->rt_ifp))
2453                 goto fail;
2454
2455         /*
2456          * Address check:
2457          *  the source address must identify a neighbor, and
2458          *  the destination address must not be a multicast address
2459          *  [RFC 2461, sec 8.2]
2460          */
2461         sip6 = mtod(m0, struct ip6_hdr *);
2462         bzero(&src_sa, sizeof(src_sa));
2463         src_sa.sin6_family = AF_INET6;
2464         src_sa.sin6_len = sizeof(src_sa);
2465         src_sa.sin6_addr = sip6->ip6_src;
2466         if (nd6_is_addr_neighbor(&src_sa, ifp) == 0)
2467                 goto fail;
2468         if (IN6_IS_ADDR_MULTICAST(&sip6->ip6_dst))
2469                 goto fail;      /* what should we do here? */
2470
2471         /* rate limit */
2472         if (icmp6_ratelimit(&sip6->ip6_src, ND_REDIRECT, 0))
2473                 goto fail;
2474
2475         /*
2476          * Since we are going to append up to 1280 bytes (= IPV6_MMTU),
2477          * we almost always ask for an mbuf cluster for simplicity.
2478          * (MHLEN < IPV6_MMTU is almost always true)
2479          */
2480 #if IPV6_MMTU >= MCLBYTES
2481 # error assumption failed about IPV6_MMTU and MCLBYTES
2482 #endif
2483         m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
2484         if (m == NULL)
2485                 goto fail;
2486         M_SETFIB(m, rt->rt_fibnum);
2487         maxlen = M_TRAILINGSPACE(m);
2488         maxlen = min(IPV6_MMTU, maxlen);
2489         /* just for safety */
2490         if (maxlen < sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr) +
2491             ((sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7)) {
2492                 goto fail;
2493         }
2494
2495         {
2496                 /* get ip6 linklocal address for ifp(my outgoing interface). */
2497                 struct in6_ifaddr *ia;
2498                 if ((ia = in6ifa_ifpforlinklocal(ifp,
2499                                                  IN6_IFF_NOTREADY|
2500                                                  IN6_IFF_ANYCAST)) == NULL)
2501                         goto fail;
2502                 ifp_ll6 = &ia->ia_addr.sin6_addr;
2503                 /* XXXRW: reference released prematurely. */
2504                 ifa_free(&ia->ia_ifa);
2505         }
2506
2507         /* get ip6 linklocal address for the router. */
2508         if (rt->rt_gateway && (rt->rt_flags & RTF_GATEWAY)) {
2509                 struct sockaddr_in6 *sin6;
2510                 sin6 = (struct sockaddr_in6 *)rt->rt_gateway;
2511                 router_ll6 = &sin6->sin6_addr;
2512                 if (!IN6_IS_ADDR_LINKLOCAL(router_ll6))
2513                         router_ll6 = (struct in6_addr *)NULL;
2514         } else
2515                 router_ll6 = (struct in6_addr *)NULL;
2516
2517         /* ip6 */
2518         ip6 = mtod(m, struct ip6_hdr *);
2519         ip6->ip6_flow = 0;
2520         ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
2521         ip6->ip6_vfc |= IPV6_VERSION;
2522         /* ip6->ip6_plen will be set later */
2523         ip6->ip6_nxt = IPPROTO_ICMPV6;
2524         ip6->ip6_hlim = 255;
2525         /* ip6->ip6_src must be linklocal addr for my outgoing if. */
2526         bcopy(ifp_ll6, &ip6->ip6_src, sizeof(struct in6_addr));
2527         bcopy(&sip6->ip6_src, &ip6->ip6_dst, sizeof(struct in6_addr));
2528
2529         /* ND Redirect */
2530         nd_rd = (struct nd_redirect *)(ip6 + 1);
2531         nd_rd->nd_rd_type = ND_REDIRECT;
2532         nd_rd->nd_rd_code = 0;
2533         nd_rd->nd_rd_reserved = 0;
2534         if (rt->rt_flags & RTF_GATEWAY) {
2535                 /*
2536                  * nd_rd->nd_rd_target must be a link-local address in
2537                  * better router cases.
2538                  */
2539                 if (!router_ll6)
2540                         goto fail;
2541                 bcopy(router_ll6, &nd_rd->nd_rd_target,
2542                     sizeof(nd_rd->nd_rd_target));
2543                 bcopy(&sip6->ip6_dst, &nd_rd->nd_rd_dst,
2544                     sizeof(nd_rd->nd_rd_dst));
2545         } else {
2546                 /* make sure redtgt == reddst */
2547                 bcopy(&sip6->ip6_dst, &nd_rd->nd_rd_target,
2548                     sizeof(nd_rd->nd_rd_target));
2549                 bcopy(&sip6->ip6_dst, &nd_rd->nd_rd_dst,
2550                     sizeof(nd_rd->nd_rd_dst));
2551         }
2552
2553         p = (u_char *)(nd_rd + 1);
2554
2555         if (!router_ll6)
2556                 goto nolladdropt;
2557
2558         {
2559                 /* target lladdr option */
2560                 int len;
2561                 struct nd_opt_hdr *nd_opt;
2562                 char *lladdr;
2563
2564                 IF_AFDATA_RLOCK(ifp);
2565                 ln = nd6_lookup(router_ll6, 0, ifp);
2566                 IF_AFDATA_RUNLOCK(ifp);
2567                 if (ln == NULL)
2568                         goto nolladdropt;
2569
2570                 len = sizeof(*nd_opt) + ifp->if_addrlen;
2571                 len = (len + 7) & ~7;   /* round by 8 */
2572                 /* safety check */
2573                 if (len + (p - (u_char *)ip6) > maxlen)
2574                         goto nolladdropt;
2575
2576                 if (ln->la_flags & LLE_VALID) {
2577                         nd_opt = (struct nd_opt_hdr *)p;
2578                         nd_opt->nd_opt_type = ND_OPT_TARGET_LINKADDR;
2579                         nd_opt->nd_opt_len = len >> 3;
2580                         lladdr = (char *)(nd_opt + 1);
2581                         bcopy(ln->ll_addr, lladdr, ifp->if_addrlen);
2582                         p += len;
2583                 }
2584         }
2585 nolladdropt:
2586         if (ln != NULL)
2587                 LLE_RUNLOCK(ln);
2588
2589         m->m_pkthdr.len = m->m_len = p - (u_char *)ip6;
2590
2591         /* just to be safe */
2592 #ifdef M_DECRYPTED      /*not openbsd*/
2593         if (m0->m_flags & M_DECRYPTED)
2594                 goto noredhdropt;
2595 #endif
2596         if (p - (u_char *)ip6 > maxlen)
2597                 goto noredhdropt;
2598
2599         {
2600                 /* redirected header option */
2601                 int len;
2602                 struct nd_opt_rd_hdr *nd_opt_rh;
2603
2604                 /*
2605                  * compute the maximum size for icmp6 redirect header option.
2606                  * XXX room for auth header?
2607                  */
2608                 len = maxlen - (p - (u_char *)ip6);
2609                 len &= ~7;
2610
2611                 /* This is just for simplicity. */
2612                 if (m0->m_pkthdr.len != m0->m_len) {
2613                         if (m0->m_next) {
2614                                 m_freem(m0->m_next);
2615                                 m0->m_next = NULL;
2616                         }
2617                         m0->m_pkthdr.len = m0->m_len;
2618                 }
2619
2620                 /*
2621                  * Redirected header option spec (RFC2461 4.6.3) talks nothing
2622                  * about padding/truncate rule for the original IP packet.
2623                  * From the discussion on IPv6imp in Feb 1999,
2624                  * the consensus was:
2625                  * - "attach as much as possible" is the goal
2626                  * - pad if not aligned (original size can be guessed by
2627                  *   original ip6 header)
2628                  * Following code adds the padding if it is simple enough,
2629                  * and truncates if not.
2630                  */
2631                 if (m0->m_next || m0->m_pkthdr.len != m0->m_len)
2632                         panic("assumption failed in %s:%d", __FILE__,
2633                             __LINE__);
2634
2635                 if (len - sizeof(*nd_opt_rh) < m0->m_pkthdr.len) {
2636                         /* not enough room, truncate */
2637                         m0->m_pkthdr.len = m0->m_len = len -
2638                             sizeof(*nd_opt_rh);
2639                 } else {
2640                         /* enough room, pad or truncate */
2641                         size_t extra;
2642
2643                         extra = m0->m_pkthdr.len % 8;
2644                         if (extra) {
2645                                 /* pad if easy enough, truncate if not */
2646                                 if (8 - extra <= M_TRAILINGSPACE(m0)) {
2647                                         /* pad */
2648                                         m0->m_len += (8 - extra);
2649                                         m0->m_pkthdr.len += (8 - extra);
2650                                 } else {
2651                                         /* truncate */
2652                                         m0->m_pkthdr.len -= extra;
2653                                         m0->m_len -= extra;
2654                                 }
2655                         }
2656                         len = m0->m_pkthdr.len + sizeof(*nd_opt_rh);
2657                         m0->m_pkthdr.len = m0->m_len = len -
2658                             sizeof(*nd_opt_rh);
2659                 }
2660
2661                 nd_opt_rh = (struct nd_opt_rd_hdr *)p;
2662                 bzero(nd_opt_rh, sizeof(*nd_opt_rh));
2663                 nd_opt_rh->nd_opt_rh_type = ND_OPT_REDIRECTED_HEADER;
2664                 nd_opt_rh->nd_opt_rh_len = len >> 3;
2665                 p += sizeof(*nd_opt_rh);
2666                 m->m_pkthdr.len = m->m_len = p - (u_char *)ip6;
2667
2668                 /* connect m0 to m */
2669                 m_tag_delete_chain(m0, NULL);
2670                 m0->m_flags &= ~M_PKTHDR;
2671                 m->m_next = m0;
2672                 m->m_pkthdr.len = m->m_len + m0->m_len;
2673                 m0 = NULL;
2674         }
2675 noredhdropt:;
2676         if (m0) {
2677                 m_freem(m0);
2678                 m0 = NULL;
2679         }
2680
2681         /* XXX: clear embedded link IDs in the inner header */
2682         in6_clearscope(&sip6->ip6_src);
2683         in6_clearscope(&sip6->ip6_dst);
2684         in6_clearscope(&nd_rd->nd_rd_target);
2685         in6_clearscope(&nd_rd->nd_rd_dst);
2686
2687         ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
2688
2689         nd_rd->nd_rd_cksum = 0;
2690         nd_rd->nd_rd_cksum = in6_cksum(m, IPPROTO_ICMPV6,
2691             sizeof(*ip6), ntohs(ip6->ip6_plen));
2692
2693         if (send_sendso_input_hook != NULL) {
2694                 mtag = m_tag_get(PACKET_TAG_ND_OUTGOING, sizeof(unsigned short),
2695                         M_NOWAIT);
2696                 if (mtag == NULL)
2697                         goto fail;
2698                 *(unsigned short *)(mtag + 1) = nd_rd->nd_rd_type;
2699                 m_tag_prepend(m, mtag);
2700         }
2701
2702         /* send the packet to outside... */
2703         ip6_output(m, NULL, NULL, 0, NULL, &outif, NULL);
2704         if (outif) {
2705                 icmp6_ifstat_inc(outif, ifs6_out_msg);
2706                 icmp6_ifstat_inc(outif, ifs6_out_redirect);
2707         }
2708         ICMP6STAT_INC(icp6s_outhist[ND_REDIRECT]);
2709
2710         return;
2711
2712 fail:
2713         if (m)
2714                 m_freem(m);
2715         if (m0)
2716                 m_freem(m0);
2717 }
2718
2719 /*
2720  * ICMPv6 socket option processing.
2721  */
2722 int
2723 icmp6_ctloutput(struct socket *so, struct sockopt *sopt)
2724 {
2725         int error = 0;
2726         int optlen;
2727         struct inpcb *inp = sotoinpcb(so);
2728         int level, op, optname;
2729
2730         if (sopt) {
2731                 level = sopt->sopt_level;
2732                 op = sopt->sopt_dir;
2733                 optname = sopt->sopt_name;
2734                 optlen = sopt->sopt_valsize;
2735         } else
2736                 level = op = optname = optlen = 0;
2737
2738         if (level != IPPROTO_ICMPV6) {
2739                 return EINVAL;
2740         }
2741
2742         switch (op) {
2743         case PRCO_SETOPT:
2744                 switch (optname) {
2745                 case ICMP6_FILTER:
2746                     {
2747                         struct icmp6_filter ic6f;
2748
2749                         if (optlen != sizeof(ic6f)) {
2750                                 error = EMSGSIZE;
2751                                 break;
2752                         }
2753                         error = sooptcopyin(sopt, &ic6f, optlen, optlen);
2754                         if (error == 0) {
2755                                 INP_WLOCK(inp);
2756                                 *inp->in6p_icmp6filt = ic6f;
2757                                 INP_WUNLOCK(inp);
2758                         }
2759                         break;
2760                     }
2761
2762                 default:
2763                         error = ENOPROTOOPT;
2764                         break;
2765                 }
2766                 break;
2767
2768         case PRCO_GETOPT:
2769                 switch (optname) {
2770                 case ICMP6_FILTER:
2771                     {
2772                         struct icmp6_filter ic6f;
2773
2774                         INP_RLOCK(inp);
2775                         ic6f = *inp->in6p_icmp6filt;
2776                         INP_RUNLOCK(inp);
2777                         error = sooptcopyout(sopt, &ic6f, sizeof(ic6f));
2778                         break;
2779                     }
2780
2781                 default:
2782                         error = ENOPROTOOPT;
2783                         break;
2784                 }
2785                 break;
2786         }
2787
2788         return (error);
2789 }
2790
2791 /*
2792  * Perform rate limit check.
2793  * Returns 0 if it is okay to send the icmp6 packet.
2794  * Returns 1 if the router SHOULD NOT send this icmp6 packet due to rate
2795  * limitation.
2796  *
2797  * XXX per-destination/type check necessary?
2798  *
2799  * dst - not used at this moment
2800  * type - not used at this moment
2801  * code - not used at this moment
2802  */
2803 static int
2804 icmp6_ratelimit(const struct in6_addr *dst, const int type,
2805     const int code)
2806 {
2807         int ret;
2808
2809         ret = 0;        /* okay to send */
2810
2811         /* PPS limit */
2812         if (!ppsratecheck(&V_icmp6errppslim_last, &V_icmp6errpps_count,
2813             V_icmp6errppslim)) {
2814                 /* The packet is subject to rate limit */
2815                 ret++;
2816         }
2817
2818         return ret;
2819 }