usr.sbin/rtadvd/if.c

   1 /*      $FreeBSD$       */
   2 /*      $KAME: if.c,v 1.17 2001/01/21 15:27:30 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
  33 #include <sys/param.h>
  34 #include <sys/socket.h>
  35 #include <sys/sysctl.h>
  36 #include <sys/ioctl.h>
  37 #include <net/if.h>
  38 #include <net/if_types.h>
  39 #include <net/ethernet.h>
  40 #include <ifaddrs.h>
  41 #include <net/route.h>
  42 #include <net/if_dl.h>
  43 #include <netinet/in.h>
  44 #include <netinet/icmp6.h>
  45 #include <unistd.h>
  46 #include <errno.h>
  47 #include <stdlib.h>
  48 #include <string.h>
  49 #include <syslog.h>
  50 #include "rtadvd.h"
  51 #include "if.h"
  52
  53 #define ROUNDUP(a, size) \
  54         (((a) & ((size)-1)) ? (1 + ((a) | ((size)-1))) : (a))
  55
  56 #define NEXT_SA(ap) (ap) = (struct sockaddr *) \
  57         ((caddr_t)(ap) + ((ap)->sa_len ? ROUNDUP((ap)->sa_len,\
  58                                                  sizeof(u_long)) :\
  59                                                  sizeof(u_long)))
  60
  61 struct if_msghdr **iflist;
  62 int iflist_init_ok;
  63 size_t ifblock_size;
  64 char *ifblock;
  65
  66 static void get_iflist(char **buf, size_t *size);
  67 static void parse_iflist(struct if_msghdr ***ifmlist_p, char *buf,
  68                        size_t bufsize);
  69
  70 static void
  71 get_rtaddrs(int addrs, struct sockaddr *sa, struct sockaddr **rti_info)
  72 {
  73         int i;
  74
  75         for (i = 0; i < RTAX_MAX; i++) {
  76                 if (addrs & (1 << i)) {
  77                         rti_info[i] = sa;
  78                         NEXT_SA(sa);
  79                 }
  80                 else
  81                         rti_info[i] = NULL;
  82         }
  83 }
  84
  85 struct sockaddr_dl *
  86 if_nametosdl(char *name)
  87 {
  88         int mib[6] = {CTL_NET, AF_ROUTE, 0, 0, NET_RT_IFLIST, 0};
  89         char *buf, *next, *lim;
  90         size_t len;
  91         struct if_msghdr *ifm;
  92         struct sockaddr *sa, *rti_info[RTAX_MAX];
  93         struct sockaddr_dl *sdl = NULL, *ret_sdl;
  94
  95         if (sysctl(mib, 6, NULL, &len, NULL, 0) < 0)
  96                 return(NULL);
  97         if ((buf = malloc(len)) == NULL)
  98                 return(NULL);
  99         if (sysctl(mib, 6, buf, &len, NULL, 0) < 0) {
 100                 free(buf);
 101                 return(NULL);
 102         }
 103
 104         lim = buf + len;
 105         for (next = buf; next < lim; next += ifm->ifm_msglen) {
 106                 ifm = (struct if_msghdr *)next;
 107                 if (ifm->ifm_type == RTM_IFINFO) {
 108                         sa = (struct sockaddr *)(ifm + 1);
 109                         get_rtaddrs(ifm->ifm_addrs, sa, rti_info);
 110                         if ((sa = rti_info[RTAX_IFP]) != NULL) {
 111                                 if (sa->sa_family == AF_LINK) {
 112                                         sdl = (struct sockaddr_dl *)sa;
 113                                         if (strlen(name) != sdl->sdl_nlen)
 114                                                 continue; /* not same len */
 115                                         if (strncmp(&sdl->sdl_data[0],
 116                                                     name,
 117                                                     sdl->sdl_nlen) == 0) {
 118                                                 break;
 119                                         }
 120                                 }
 121                         }
 122                 }
 123         }
 124         if (next == lim) {
 125                 /* search failed */
 126                 free(buf);
 127                 return(NULL);
 128         }
 129
 130         if ((ret_sdl = malloc(sdl->sdl_len)) == NULL)
 131                 goto end;
 132         memcpy((caddr_t)ret_sdl, (caddr_t)sdl, sdl->sdl_len);
 133
 134 end:
 135         free(buf);
 136         return(ret_sdl);
 137 }
 138
 139 int
 140 if_getmtu(char *name)
 141 {
 142         struct ifaddrs *ifap, *ifa;
 143         struct if_data *ifd;
 144         u_long mtu = 0;
 145
 146         if (getifaddrs(&ifap) < 0)
 147                 return(0);
 148         for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
 149                 if (strcmp(ifa->ifa_name, name) == 0) {
 150                         ifd = ifa->ifa_data;
 151                         if (ifd)
 152                                 mtu = ifd->ifi_mtu;
 153                         break;
 154                 }
 155         }
 156         freeifaddrs(ifap);
 157
 158 #ifdef SIOCGIFMTU               /* XXX: this ifdef may not be necessary */
 159         if (mtu == 0) {
 160                 struct ifreq ifr;
 161                 int s;
 162
 163                 if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0)
 164                         return(0);
 165
 166                 ifr.ifr_addr.sa_family = AF_INET6;
 167                 strncpy(ifr.ifr_name, name,
 168                         sizeof(ifr.ifr_name));
 169                 if (ioctl(s, SIOCGIFMTU, (caddr_t)&ifr) < 0) {
 170                         close(s);
 171                         return(0);
 172                 }
 173                 close(s);
 174
 175                 mtu = ifr.ifr_mtu;
 176         }
 177 #endif
 178
 179         return(mtu);
 180 }
 181
 182 /* give interface index and its old flags, then new flags returned */
 183 int
 184 if_getflags(int ifindex, int oifflags)
 185 {
 186         struct ifreq ifr;
 187         int s;
 188
 189         if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
 190                 syslog(LOG_ERR, "<%s> socket: %s", __func__,
 191                        strerror(errno));
 192                 return (oifflags & ~IFF_UP);
 193         }
 194
 195         if_indextoname(ifindex, ifr.ifr_name);
 196         if (ioctl(s, SIOCGIFFLAGS, (caddr_t)&ifr) < 0) {
 197                 syslog(LOG_ERR, "<%s> ioctl:SIOCGIFFLAGS: failed for %s",
 198                        __func__, ifr.ifr_name);
 199                 close(s);
 200                 return (oifflags & ~IFF_UP);
 201         }
 202         close(s);
 203         return (ifr.ifr_flags);
 204 }
 205
 206 #define ROUNDUP8(a) (1 + (((a) - 1) | 7))
 207 int
 208 lladdropt_length(struct sockaddr_dl *sdl)
 209 {
 210         switch (sdl->sdl_type) {
 211         case IFT_ETHER:
 212                 return(ROUNDUP8(ETHER_ADDR_LEN + 2));
 213         default:
 214                 return(0);
 215         }
 216 }
 217
 218 void
 219 lladdropt_fill(struct sockaddr_dl *sdl, struct nd_opt_hdr *ndopt)
 220 {
 221         char *addr;
 222
 223         ndopt->nd_opt_type = ND_OPT_SOURCE_LINKADDR; /* fixed */
 224
 225         switch (sdl->sdl_type) {
 226         case IFT_ETHER:
 227                 ndopt->nd_opt_len = (ROUNDUP8(ETHER_ADDR_LEN + 2)) >> 3;
 228                 addr = (char *)(ndopt + 1);
 229                 memcpy(addr, LLADDR(sdl), ETHER_ADDR_LEN);
 230                 break;
 231         default:
 232                 syslog(LOG_ERR, "<%s> unsupported link type(%d)",
 233                     __func__, sdl->sdl_type);
 234                 exit(1);
 235         }
 236
 237         return;
 238 }
 239
 240 int
 241 rtbuf_len()
 242 {
 243         size_t len;
 244
 245         int mib[6] = {CTL_NET, AF_ROUTE, 0, AF_INET6, NET_RT_DUMP, 0};
 246
 247         if (sysctl(mib, 6, NULL, &len, NULL, 0) < 0)
 248                 return(-1);
 249
 250         return(len);
 251 }
 252
 253 #define FILTER_MATCH(type, filter) ((0x1 << type) & filter)
 254 #define SIN6(s) ((struct sockaddr_in6 *)(s))
 255 #define SDL(s) ((struct sockaddr_dl *)(s))
 256 char *
 257 get_next_msg(char *buf, char *lim, int ifindex, size_t *lenp, int filter)
 258 {
 259         struct rt_msghdr *rtm;
 260         struct ifa_msghdr *ifam;
 261         struct sockaddr *sa, *dst, *gw, *ifa, *rti_info[RTAX_MAX];
 262
 263         *lenp = 0;
 264         for (rtm = (struct rt_msghdr *)buf;
 265              rtm < (struct rt_msghdr *)lim;
 266              rtm = (struct rt_msghdr *)(((char *)rtm) + rtm->rtm_msglen)) {
 267                 /* just for safety */
 268                 if (!rtm->rtm_msglen) {
 269                         syslog(LOG_WARNING, "<%s> rtm_msglen is 0 "
 270                                 "(buf=%p lim=%p rtm=%p)", __func__,
 271                                 buf, lim, rtm);
 272                         break;
 273                 }
 274                 if (FILTER_MATCH(rtm->rtm_type, filter) == 0) {
 275                         continue;
 276                 }
 277
 278                 switch (rtm->rtm_type) {
 279                 case RTM_GET:
 280                 case RTM_ADD:
 281                 case RTM_DELETE:
 282                         /* address related checks */
 283                         sa = (struct sockaddr *)(rtm + 1);
 284                         get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
 285                         if ((dst = rti_info[RTAX_DST]) == NULL ||
 286                             dst->sa_family != AF_INET6)
 287                                 continue;
 288
 289                         if (IN6_IS_ADDR_LINKLOCAL(&SIN6(dst)->sin6_addr) ||
 290                             IN6_IS_ADDR_MULTICAST(&SIN6(dst)->sin6_addr))
 291                                 continue;
 292
 293                         if ((gw = rti_info[RTAX_GATEWAY]) == NULL ||
 294                             gw->sa_family != AF_LINK)
 295                                 continue;
 296                         if (ifindex && SDL(gw)->sdl_index != ifindex)
 297                                 continue;
 298
 299                         if (rti_info[RTAX_NETMASK] == NULL)
 300                                 continue;
 301
 302                         /* found */
 303                         *lenp = rtm->rtm_msglen;
 304                         return (char *)rtm;
 305                         /* NOTREACHED */
 306                 case RTM_NEWADDR:
 307                 case RTM_DELADDR:
 308                         ifam = (struct ifa_msghdr *)rtm;
 309
 310                         /* address related checks */
 311                         sa = (struct sockaddr *)(ifam + 1);
 312                         get_rtaddrs(ifam->ifam_addrs, sa, rti_info);
 313                         if ((ifa = rti_info[RTAX_IFA]) == NULL ||
 314                             (ifa->sa_family != AF_INET &&
 315                              ifa->sa_family != AF_INET6))
 316                                 continue;
 317
 318                         if (ifa->sa_family == AF_INET6 &&
 319                             (IN6_IS_ADDR_LINKLOCAL(&SIN6(ifa)->sin6_addr) ||
 320                              IN6_IS_ADDR_MULTICAST(&SIN6(ifa)->sin6_addr)))
 321                                 continue;
 322
 323                         if (ifindex && ifam->ifam_index != ifindex)
 324                                 continue;
 325
 326                         /* found */
 327                         *lenp = ifam->ifam_msglen;
 328                         return (char *)rtm;
 329                         /* NOTREACHED */
 330                 case RTM_IFINFO:
 331                         /* found */
 332                         *lenp = rtm->rtm_msglen;
 333                         return (char *)rtm;
 334                         /* NOTREACHED */
 335                 }
 336         }
 337
 338         return (char *)rtm;
 339 }
 340 #undef FILTER_MATCH
 341
 342 struct in6_addr *
 343 get_addr(char *buf)
 344 {
 345         struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
 346         struct sockaddr *sa, *rti_info[RTAX_MAX];
 347
 348         sa = (struct sockaddr *)(rtm + 1);
 349         get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
 350
 351         return(&SIN6(rti_info[RTAX_DST])->sin6_addr);
 352 }
 353
 354 int
 355 get_rtm_ifindex(char *buf)
 356 {
 357         struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
 358         struct sockaddr *sa, *rti_info[RTAX_MAX];
 359
 360         sa = (struct sockaddr *)(rtm + 1);
 361         get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
 362
 363         return(((struct sockaddr_dl *)rti_info[RTAX_GATEWAY])->sdl_index);
 364 }
 365
 366 int
 367 get_ifm_ifindex(char *buf)
 368 {
 369         struct if_msghdr *ifm = (struct if_msghdr *)buf;
 370
 371         return ((int)ifm->ifm_index);
 372 }
 373
 374 int
 375 get_ifam_ifindex(char *buf)
 376 {
 377         struct ifa_msghdr *ifam = (struct ifa_msghdr *)buf;
 378
 379         return ((int)ifam->ifam_index);
 380 }
 381
 382 int
 383 get_ifm_flags(char *buf)
 384 {
 385         struct if_msghdr *ifm = (struct if_msghdr *)buf;
 386
 387         return (ifm->ifm_flags);
 388 }
 389
 390 int
 391 get_prefixlen(char *buf)
 392 {
 393         struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
 394         struct sockaddr *sa, *rti_info[RTAX_MAX];
 395         u_char *p, *lim;
 396
 397         sa = (struct sockaddr *)(rtm + 1);
 398         get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
 399         sa = rti_info[RTAX_NETMASK];
 400
 401         p = (u_char *)(&SIN6(sa)->sin6_addr);
 402         lim = (u_char *)sa + sa->sa_len;
 403         return prefixlen(p, lim);
 404 }
 405
 406 int
 407 prefixlen(u_char *p, u_char *lim)
 408 {
 409         int masklen;
 410
 411         for (masklen = 0; p < lim; p++) {
 412                 switch (*p) {
 413                 case 0xff:
 414                         masklen += 8;
 415                         break;
 416                 case 0xfe:
 417                         masklen += 7;
 418                         break;
 419                 case 0xfc:
 420                         masklen += 6;
 421                         break;
 422                 case 0xf8:
 423                         masklen += 5;
 424                         break;
 425                 case 0xf0:
 426                         masklen += 4;
 427                         break;
 428                 case 0xe0:
 429                         masklen += 3;
 430                         break;
 431                 case 0xc0:
 432                         masklen += 2;
 433                         break;
 434                 case 0x80:
 435                         masklen += 1;
 436                         break;
 437                 case 0x00:
 438                         break;
 439                 default:
 440                         return(-1);
 441                 }
 442         }
 443
 444         return(masklen);
 445 }
 446
 447 int
 448 rtmsg_type(char *buf)
 449 {
 450         struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
 451
 452         return(rtm->rtm_type);
 453 }
 454
 455 int
 456 rtmsg_len(char *buf)
 457 {
 458         struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
 459
 460         return(rtm->rtm_msglen);
 461 }
 462
 463 int
 464 ifmsg_len(char *buf)
 465 {
 466         struct if_msghdr *ifm = (struct if_msghdr *)buf;
 467
 468         return(ifm->ifm_msglen);
 469 }
 470
 471 /*
 472  * alloc buffer and get if_msghdrs block from kernel,
 473  * and put them into the buffer
 474  */
 475 static void
 476 get_iflist(char **buf, size_t *size)
 477 {
 478         int mib[6];
 479
 480         mib[0] = CTL_NET;
 481         mib[1] = PF_ROUTE;
 482         mib[2] = 0;
 483         mib[3] = AF_INET6;
 484         mib[4] = NET_RT_IFLIST;
 485         mib[5] = 0;
 486
 487         if (sysctl(mib, 6, NULL, size, NULL, 0) < 0) {
 488                 syslog(LOG_ERR, "<%s> sysctl: iflist size get failed",
 489                        __func__);
 490                 exit(1);
 491         }
 492         if ((*buf = malloc(*size)) == NULL) {
 493                 syslog(LOG_ERR, "<%s> malloc failed", __func__);
 494                 exit(1);
 495         }
 496         if (sysctl(mib, 6, *buf, size, NULL, 0) < 0) {
 497                 syslog(LOG_ERR, "<%s> sysctl: iflist get failed",
 498                        __func__);
 499                 exit(1);
 500         }
 501         return;
 502 }
 503
 504 /*
 505  * alloc buffer and parse if_msghdrs block passed as arg,
 506  * and init the buffer as list of pointers ot each of the if_msghdr.
 507  */
 508 static void
 509 parse_iflist(struct if_msghdr ***ifmlist_p, char *buf, size_t bufsize)
 510 {
 511         int iflentry_size, malloc_size;
 512         struct if_msghdr *ifm;
 513         struct ifa_msghdr *ifam;
 514         char *lim;
 515
 516         /*
 517          * Estimate least size of an iflist entry, to be obtained from kernel.
 518          * Should add sizeof(sockaddr) ??
 519          */
 520         iflentry_size = sizeof(struct if_msghdr);
 521         /* roughly estimate max list size of pointers to each if_msghdr */
 522         malloc_size = (bufsize/iflentry_size) * sizeof(size_t);
 523         if ((*ifmlist_p = (struct if_msghdr **)malloc(malloc_size)) == NULL) {
 524                 syslog(LOG_ERR, "<%s> malloc failed", __func__);
 525                 exit(1);
 526         }
 527
 528         lim = buf + bufsize;
 529         for (ifm = (struct if_msghdr *)buf; ifm < (struct if_msghdr *)lim;) {
 530                 if (ifm->ifm_msglen == 0) {
 531                         syslog(LOG_WARNING, "<%s> ifm_msglen is 0 "
 532                                "(buf=%p lim=%p ifm=%p)", __func__,
 533                                buf, lim, ifm);
 534                         return;
 535                 }
 536
 537                 if (ifm->ifm_type == RTM_IFINFO) {
 538                         (*ifmlist_p)[ifm->ifm_index] = ifm;
 539                 } else {
 540                         syslog(LOG_ERR, "out of sync parsing NET_RT_IFLIST\n"
 541                                "expected %d, got %d\n msglen = %d\n"
 542                                "buf:%p, ifm:%p, lim:%p\n",
 543                                RTM_IFINFO, ifm->ifm_type, ifm->ifm_msglen,
 544                                buf, ifm, lim);
 545                         exit (1);
 546                 }
 547                 for (ifam = (struct ifa_msghdr *)
 548                         ((char *)ifm + ifm->ifm_msglen);
 549                      ifam < (struct ifa_msghdr *)lim;
 550                      ifam = (struct ifa_msghdr *)
 551                         ((char *)ifam + ifam->ifam_msglen)) {
 552                         /* just for safety */
 553                         if (!ifam->ifam_msglen) {
 554                                 syslog(LOG_WARNING, "<%s> ifa_msglen is 0 "
 555                                        "(buf=%p lim=%p ifam=%p)", __func__,
 556                                        buf, lim, ifam);
 557                                 return;
 558                         }
 559                         if (ifam->ifam_type != RTM_NEWADDR)
 560                                 break;
 561                 }
 562                 ifm = (struct if_msghdr *)ifam;
 563         }
 564 }
 565
 566 void
 567 init_iflist()
 568 {
 569         if (ifblock) {
 570                 free(ifblock);
 571                 ifblock_size = 0;
 572         }
 573         if (iflist)
 574                 free(iflist);
 575         /* get iflist block from kernel */
 576         get_iflist(&ifblock, &ifblock_size);
 577
 578         /* make list of pointers to each if_msghdr */
 579         parse_iflist(&iflist, ifblock, ifblock_size);
 580 }