usr.sbin/rtadvd/rrenum.c

   1 /*      $NetBSD: rrenum.c,v 1.18 2015/06/05 15:41:59 roy Exp $  */
   2 /*      $KAME: rrenum.c,v 1.14 2004/06/14 05:36:00 itojun Exp $ */
   3
   4 /*
   5  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. Neither the name of the project nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32 #include <sys/types.h>
  33 #include <sys/param.h>
  34 #include <sys/ioctl.h>
  35 #include <sys/socket.h>
  36 #include <sys/sysctl.h>
  37
  38 #include <net/if.h>
  39 #ifdef __FreeBSD__
  40 #include <net/if_var.h>
  41 #endif
  42 #include <net/route.h>
  43 #include <netinet/in.h>
  44 #include <netinet/in_var.h>
  45 #include <netinet/icmp6.h>
  46
  47 #include <arpa/inet.h>
  48
  49 #include <errno.h>
  50 #include <string.h>
  51 #include <stdlib.h>
  52 #include <syslog.h>
  53 #include "rtadvd.h"
  54 #include "rrenum.h"
  55 #include "if.h"
  56
  57 #define RR_ISSET_SEGNUM(segnum_bits, segnum) \
  58         ((((segnum_bits)[(segnum) >> 5]) & (1 << ((segnum) & 31))) != 0)
  59 #define RR_SET_SEGNUM(segnum_bits, segnum) \
  60         (((segnum_bits)[(segnum) >> 5]) |= (1 << ((segnum) & 31)))
  61
  62 struct rr_operation {
  63         u_long  rro_seqnum;
  64         u_long  rro_segnum_bits[8];
  65 };
  66
  67 static struct rr_operation rro;
  68 static int rr_rcvifindex;
  69 static int rrcmd2pco[RPM_PCO_MAX] = {
  70         0,
  71         SIOCAIFPREFIX_IN6,
  72         SIOCCIFPREFIX_IN6,
  73         SIOCSGIFPREFIX_IN6
  74 };
  75 static int s = -1;
  76
  77 /*
  78  * Check validity of a Prefix Control Operation(PCO).
  79  * Return 0 on success, 1 on failure.
  80  */
  81 static int
  82 rr_pco_check(int len, struct rr_pco_match *rpm)
  83 {
  84         struct rr_pco_use *rpu, *rpulim;
  85         int checklen;
  86
  87         /* rpm->rpm_len must be (4N * 3) as router-renum-05.txt */
  88         if ((rpm->rpm_len - 3) < 0 || /* must be at least 3 */
  89             (rpm->rpm_len - 3) & 0x3) { /* must be multiple of 4 */
  90                 syslog(LOG_WARNING, "<%s> rpm_len %d is not 4N * 3",
  91                        __func__, rpm->rpm_len);
  92                 return 1;
  93         }
  94         /* rpm->rpm_code must be valid value */
  95         switch (rpm->rpm_code) {
  96         case RPM_PCO_ADD:
  97         case RPM_PCO_CHANGE:
  98         case RPM_PCO_SETGLOBAL:
  99                 break;
 100         default:
 101                 syslog(LOG_WARNING, "<%s> unknown rpm_code %d", __func__,
 102                        rpm->rpm_code);
 103                 return 1;
 104         }
 105         /* rpm->rpm_matchlen must be 0 to 128 inclusive */
 106         if (rpm->rpm_matchlen > 128) {
 107                 syslog(LOG_WARNING, "<%s> rpm_matchlen %d is over 128",
 108                        __func__, rpm->rpm_matchlen);
 109                 return 1;
 110         }
 111
 112         /*
 113          * rpu->rpu_uselen, rpu->rpu_keeplen, and sum of them must be
 114          * between 0 and 128 inclusive
 115          */
 116         for (rpu = (struct rr_pco_use *)(rpm + 1),
 117              rpulim = (struct rr_pco_use *)((char *)rpm + len);
 118              rpu < rpulim;
 119              rpu += 1) {
 120                 checklen = rpu->rpu_uselen;
 121                 checklen += rpu->rpu_keeplen;
 122                 /*
 123                  * omit these check, because either of rpu_uselen
 124                  * and rpu_keeplen is unsigned char
 125                  *  (128 > rpu_uselen > 0)
 126                  *  (128 > rpu_keeplen > 0)
 127                  *  (rpu_uselen + rpu_keeplen > 0)
 128                  */
 129                 if (checklen > 128) {
 130                         syslog(LOG_WARNING, "<%s> sum of rpu_uselen %d and"
 131                                " rpu_keeplen %d is %d(over 128)",
 132                                __func__, rpu->rpu_uselen,
 133                                rpu->rpu_keeplen,
 134                                rpu->rpu_uselen + rpu->rpu_keeplen);
 135                         return 1;
 136                 }
 137         }
 138         return 0;
 139 }
 140
 141 static void
 142 do_use_prefix(int len, struct rr_pco_match *rpm,
 143               struct in6_rrenumreq *irr, int ifindex)
 144 {
 145         struct rr_pco_use *rpu, *rpulim;
 146         struct rainfo *rai;
 147         struct prefix *pp;
 148
 149         rpu = (struct rr_pco_use *)(rpm + 1);
 150         rpulim = (struct rr_pco_use *)((char *)rpm + len);
 151
 152         if (rpu == rpulim) {    /* no use prefix */
 153                 if (rpm->rpm_code == RPM_PCO_ADD)
 154                         return;
 155
 156                 irr->irr_u_uselen = 0;
 157                 irr->irr_u_keeplen = 0;
 158                 irr->irr_raf_mask_onlink = 0;
 159                 irr->irr_raf_mask_auto = 0;
 160                 irr->irr_vltime = 0;
 161                 irr->irr_pltime = 0;
 162                 memset(&irr->irr_flags, 0, sizeof(irr->irr_flags));
 163                 irr->irr_useprefix.sin6_len = 0; /* let it mean, no addition */
 164                 irr->irr_useprefix.sin6_family = 0;
 165                 irr->irr_useprefix.sin6_addr = in6addr_any;
 166                 if (ioctl(s, rrcmd2pco[rpm->rpm_code], irr) < 0 &&
 167                     errno != EADDRNOTAVAIL)
 168                         syslog(LOG_ERR, "<%s> ioctl: %m", __func__);
 169                 return;
 170         }
 171
 172         for (rpu = (struct rr_pco_use *)(rpm + 1),
 173              rpulim = (struct rr_pco_use *)((char *)rpm + len);
 174              rpu < rpulim;
 175              rpu += 1) {
 176                 /* init in6_rrenumreq fields */
 177                 irr->irr_u_uselen = rpu->rpu_uselen;
 178                 irr->irr_u_keeplen = rpu->rpu_keeplen;
 179                 irr->irr_raf_mask_onlink =
 180                         !!(rpu->rpu_ramask & ICMP6_RR_PCOUSE_RAFLAGS_ONLINK);
 181                 irr->irr_raf_mask_auto =
 182                         !!(rpu->rpu_ramask & ICMP6_RR_PCOUSE_RAFLAGS_AUTO);
 183                 irr->irr_vltime = ntohl(rpu->rpu_vltime);
 184                 irr->irr_pltime = ntohl(rpu->rpu_pltime);
 185                 irr->irr_raf_onlink =
 186                         (rpu->rpu_raflags & ICMP6_RR_PCOUSE_RAFLAGS_ONLINK) == 0 ? 0 : 1;
 187                 irr->irr_raf_auto =
 188                         (rpu->rpu_raflags & ICMP6_RR_PCOUSE_RAFLAGS_AUTO) == 0 ? 0 : 1;
 189                 irr->irr_rrf_decrvalid =
 190                         (rpu->rpu_flags & ICMP6_RR_PCOUSE_FLAGS_DECRVLTIME) == 0 ? 0 : 1;
 191                 irr->irr_rrf_decrprefd =
 192                         (rpu->rpu_flags & ICMP6_RR_PCOUSE_FLAGS_DECRPLTIME) == 0 ? 0 : 1;
 193                 irr->irr_useprefix.sin6_len = sizeof(irr->irr_useprefix);
 194                 irr->irr_useprefix.sin6_family = AF_INET6;
 195                 irr->irr_useprefix.sin6_addr = rpu->rpu_prefix;
 196
 197                 if (ioctl(s, rrcmd2pco[rpm->rpm_code], irr) < 0 &&
 198                     errno != EADDRNOTAVAIL)
 199                         syslog(LOG_ERR, "<%s> ioctl: %m", __func__);
 200
 201                 /* very adhoc: should be rewritten */
 202                 if (rpm->rpm_code == RPM_PCO_CHANGE &&
 203                     IN6_ARE_ADDR_EQUAL(&rpm->rpm_prefix, &rpu->rpu_prefix) &&
 204                     rpm->rpm_matchlen == rpu->rpu_uselen &&
 205                     rpu->rpu_uselen == rpu->rpu_keeplen) {
 206                         if ((rai = if_indextorainfo(ifindex)) == NULL)
 207                                 continue; /* non-advertising IF */
 208
 209                         TAILQ_FOREACH(pp, &rai->prefix, next) {
 210                                 struct timespec now;
 211
 212                                 if (prefix_match(&pp->prefix, pp->prefixlen,
 213                                                  &rpm->rpm_prefix,
 214                                                  rpm->rpm_matchlen)) {
 215                                         /* change parameters */
 216                                         pp->validlifetime = ntohl(rpu->rpu_vltime);
 217                                         pp->preflifetime = ntohl(rpu->rpu_pltime);
 218                                         if (irr->irr_rrf_decrvalid) {
 219                                                 clock_gettime(CLOCK_MONOTONIC,
 220                                                     &now);
 221                                                 pp->vltimeexpire =
 222                                                         now.tv_sec + pp->validlifetime;
 223                                         } else
 224                                                 pp->vltimeexpire = 0;
 225                                         if (irr->irr_rrf_decrprefd) {
 226                                                 clock_gettime(CLOCK_MONOTONIC,
 227                                                     &now);
 228                                                 pp->pltimeexpire =
 229                                                         now.tv_sec + pp->preflifetime;
 230                                         } else
 231                                                 pp->pltimeexpire = 0;
 232                                 }
 233                         }
 234                 }
 235         }
 236 }
 237
 238 /*
 239  * process a Prefix Control Operation(PCO).
 240  * return 0 on success, 1 on failure
 241  */
 242 static int
 243 do_pco(struct icmp6_router_renum *rr, int len, struct rr_pco_match *rpm)
 244 {
 245         int ifindex = 0;
 246         struct in6_rrenumreq irr;
 247         struct rainfo *rai;
 248
 249         if ((rr_pco_check(len, rpm) != 0))
 250                 return 1;
 251
 252         if (s == -1 && (s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
 253                 syslog(LOG_ERR, "<%s> socket: %m", __func__);
 254                 exit(1);
 255         }
 256
 257         memset(&irr, 0, sizeof(irr));
 258         irr.irr_origin = PR_ORIG_RR;
 259         irr.irr_m_len = rpm->rpm_matchlen;
 260         irr.irr_m_minlen = rpm->rpm_minlen;
 261         irr.irr_m_maxlen = rpm->rpm_maxlen;
 262         irr.irr_matchprefix.sin6_len = sizeof(irr.irr_matchprefix);
 263         irr.irr_matchprefix.sin6_family = AF_INET6;
 264         irr.irr_matchprefix.sin6_addr = rpm->rpm_prefix;
 265
 266         /*
 267          * if ICMP6_RR_FLAGS_FORCEAPPLY(A flag) is 0 and IFF_UP is off,
 268          * the interface is not applied
 269          */
 270
 271         if (rr->rr_flags & ICMP6_RR_FLAGS_FORCEAPPLY) {
 272                 while (if_indextoname(++ifindex, irr.irr_name)) {
 273                         rai = if_indextorainfo(ifindex);
 274                         if (rai && (rai->ifflags & IFF_UP)) {
 275                                 /* TODO: interface scope check */
 276                                 do_use_prefix(len, rpm, &irr, ifindex);
 277                         }
 278                 }
 279         }
 280         if (errno == ENXIO)
 281                 return 0;
 282         else if (errno) {
 283                 syslog(LOG_ERR, "<%s> if_indextoname: %m", __func__);
 284                 return 1;
 285         }
 286         return 0;
 287 }
 288
 289 /*
 290  * call do_pco() for each Prefix Control Operations(PCOs) in a received
 291  * Router Renumbering Command packet.
 292  * return 0 on success, 1 on failure
 293  */
 294 static int
 295 do_rr(size_t len, struct icmp6_router_renum *rr)
 296 {
 297         struct rr_pco_match *rpm;
 298         char *cp, *lim;
 299
 300         lim = (char *)rr + len;
 301         cp = (char *)(rr + 1);
 302         len -= sizeof(struct icmp6_router_renum);
 303
 304         while (cp < lim) {
 305                 size_t rpmlen;
 306
 307                 rpm = (struct rr_pco_match *)cp;
 308                 if (len < sizeof(struct rr_pco_match)) {
 309                     tooshort:
 310                         syslog(LOG_ERR, "<%s> pkt too short. left len = %zd. "
 311                                "garbage at end of pkt?", __func__, len);
 312                         return 1;
 313                 }
 314                 rpmlen = rpm->rpm_len << 3;
 315                 if (len < rpmlen)
 316                         goto tooshort;
 317
 318                 if (do_pco(rr, rpmlen, rpm)) {
 319                         syslog(LOG_WARNING, "<%s> invalid PCO", __func__);
 320                         goto next;
 321                 }
 322
 323             next:
 324                 cp += rpmlen;
 325                 len -= rpmlen;
 326         }
 327
 328         return 0;
 329 }
 330
 331 /*
 332  * check validity of a router renumbering command packet
 333  * return 0 on success, 1 on failure
 334  */
 335 static int
 336 rr_command_check(size_t len, struct icmp6_router_renum *rr,
 337     struct in6_addr *from, struct in6_addr *dst)
 338 {
 339         char ntopbuf[INET6_ADDRSTRLEN];
 340
 341         /* omit rr minimal length check. hope kernel have done it. */
 342         /* rr_command length check */
 343         if (len < (sizeof(struct icmp6_router_renum) +
 344                    sizeof(struct rr_pco_match))) {
 345                 syslog(LOG_ERR, "<%s> rr_command len %zd is too short",
 346                        __func__, len);
 347                 return 1;
 348         }
 349
 350         /* destination check. only for multicast. omit unicast check. */
 351         if (IN6_IS_ADDR_MULTICAST(dst) && !IN6_IS_ADDR_MC_LINKLOCAL(dst) &&
 352             !IN6_IS_ADDR_MC_SITELOCAL(dst)) {
 353                 syslog(LOG_ERR, "<%s> dst mcast addr %s is illegal",
 354                        __func__,
 355                        inet_ntop(AF_INET6, dst, ntopbuf, INET6_ADDRSTRLEN));
 356                 return 1;
 357         }
 358
 359         /* seqnum and segnum check */
 360         if (rro.rro_seqnum > rr->rr_seqnum) {
 361                 syslog(LOG_WARNING,
 362                        "<%s> rcvd old seqnum %d from %s",
 363                        __func__, (uint32_t)ntohl(rr->rr_seqnum),
 364                        inet_ntop(AF_INET6, from, ntopbuf, INET6_ADDRSTRLEN));
 365                 return 1;
 366         }
 367         if (rro.rro_seqnum == rr->rr_seqnum &&
 368             (rr->rr_flags & ICMP6_RR_FLAGS_TEST) == 0 &&
 369             RR_ISSET_SEGNUM(rro.rro_segnum_bits, rr->rr_segnum)) {
 370                 if ((rr->rr_flags & ICMP6_RR_FLAGS_REQRESULT) != 0)
 371                         syslog(LOG_WARNING,
 372                                "<%s> rcvd duped segnum %d from %s",
 373                                __func__, rr->rr_segnum,
 374                                inet_ntop(AF_INET6, from, ntopbuf,
 375                                          INET6_ADDRSTRLEN));
 376                 return 0;
 377         }
 378
 379         /* update seqnum */
 380         if (rro.rro_seqnum != rr->rr_seqnum) {
 381                 /* then must be "<" */
 382
 383                 /* init rro_segnum_bits */
 384                 memset(rro.rro_segnum_bits, 0,
 385                        sizeof(rro.rro_segnum_bits));
 386         }
 387         rro.rro_seqnum = rr->rr_seqnum;
 388
 389         return 0;
 390 }
 391
 392 static void
 393 rr_command_input(int len, struct icmp6_router_renum *rr,
 394                  struct in6_addr *from, struct in6_addr *dst)
 395 {
 396         /* rr_command validity check */
 397         if (rr_command_check(len, rr, from, dst))
 398                 goto failed;
 399         if ((rr->rr_flags & (ICMP6_RR_FLAGS_TEST|ICMP6_RR_FLAGS_REQRESULT)) ==
 400             ICMP6_RR_FLAGS_TEST)
 401                 return;
 402
 403         /* do router renumbering */
 404         if (do_rr(len, rr)) {
 405                 goto failed;
 406         }
 407
 408         /* update segnum */
 409         RR_SET_SEGNUM(rro.rro_segnum_bits, rr->rr_segnum);
 410
 411         return;
 412
 413     failed:
 414         syslog(LOG_ERR, "<%s> received RR was invalid", __func__);
 415         return;
 416 }
 417
 418 void
 419 rr_input(size_t len, struct icmp6_router_renum *rr, struct in6_pktinfo *pi,
 420          struct sockaddr_in6 *from, struct in6_addr *dst)
 421 {
 422         char ntopbuf[2][INET6_ADDRSTRLEN], ifnamebuf[IFNAMSIZ];
 423
 424         syslog(LOG_DEBUG,
 425                "<%s> RR received from %s to %s on %s",
 426                __func__,
 427                inet_ntop(AF_INET6, &from->sin6_addr,
 428                          ntopbuf[0], INET6_ADDRSTRLEN),
 429                inet_ntop(AF_INET6, &dst, ntopbuf[1], INET6_ADDRSTRLEN),
 430                if_indextoname(pi->ipi6_ifindex, ifnamebuf));
 431
 432         /* packet validation based on Section 4.1 of RFC2894 */
 433         if (len < sizeof(struct icmp6_router_renum)) {
 434                 syslog(LOG_NOTICE,
 435                        "<%s>: RR short message (size %zd) from %s to %s on %s",
 436                        __func__, len,
 437                        inet_ntop(AF_INET6, &from->sin6_addr,
 438                                  ntopbuf[0], INET6_ADDRSTRLEN),
 439                        inet_ntop(AF_INET6, &dst, ntopbuf[1], INET6_ADDRSTRLEN),
 440                        if_indextoname(pi->ipi6_ifindex, ifnamebuf));
 441                 return;
 442         }
 443
 444         /*
 445          * If the IPv6 destination address is neither an All Routers multicast
 446          * address [AARCH] nor one of the receiving router's unicast addresses,
 447          * the message MUST be discarded and SHOULD be logged to network
 448          * management.
 449          * We rely on the kernel input routine for unicast addresses, and thus
 450          * check multicast destinations only.
 451          */
 452         if (IN6_IS_ADDR_MULTICAST(&pi->ipi6_addr) &&
 453             !IN6_ARE_ADDR_EQUAL(&sin6_sitelocal_allrouters.sin6_addr,
 454             &pi->ipi6_addr))
 455         {
 456                 syslog(LOG_NOTICE,
 457                        "<%s>: RR message with invalid destination (%s) "
 458                        "from %s on %s",
 459                        __func__,
 460                        inet_ntop(AF_INET6, &dst, ntopbuf[0], INET6_ADDRSTRLEN),
 461                        inet_ntop(AF_INET6, &from->sin6_addr,
 462                                  ntopbuf[1], INET6_ADDRSTRLEN),
 463                        if_indextoname(pi->ipi6_ifindex, ifnamebuf));
 464                 return;
 465         }
 466
 467         rr_rcvifindex = pi->ipi6_ifindex;
 468
 469         switch (rr->rr_code) {
 470         case ICMP6_ROUTER_RENUMBERING_COMMAND:
 471                 rr_command_input(len, rr, &from->sin6_addr, dst);
 472                 /* TODO: send reply msg */
 473                 break;
 474         case ICMP6_ROUTER_RENUMBERING_RESULT:
 475                 /* RESULT will be processed by rrenumd */
 476                 break;
 477         case ICMP6_ROUTER_RENUMBERING_SEQNUM_RESET:
 478                 /* TODO: sequence number reset */
 479                 break;
 480         default:
 481                 syslog(LOG_ERR, "<%s> received unknown code %d",
 482                        __func__, rr->rr_code);
 483                 break;
 484
 485         }
 486
 487         return;
 488 }