usr.sbin/rtadvd/if.c

   1 /*      $NetBSD: if.c,v 1.23 2015/06/05 15:41:59 roy Exp $      */
   2 /*      $KAME: if.c,v 1.36 2004/11/30 22:32:01 suz 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/queue.h>
  35 #include <sys/socket.h>
  36 #include <sys/sysctl.h>
  37 #include <sys/ioctl.h>
  38 #include <net/if.h>
  39 #include <net/if_types.h>
  40 #include <ifaddrs.h>
  41 #ifdef __FreeBSD__
  42 #include <net/ethernet.h>
  43 #else
  44 #include <net/if_ether.h>
  45 #endif
  46 #include <net/route.h>
  47 #include <net/if_dl.h>
  48 #include <netinet/in.h>
  49 #include <netinet/icmp6.h>
  50 #include <unistd.h>
  51 #include <errno.h>
  52 #include <stdlib.h>
  53 #include <string.h>
  54 #include <syslog.h>
  55
  56 #include "rtadvd.h"
  57 #include "if.h"
  58
  59 #ifndef RT_ROUNDUP
  60 #define RT_ROUNDUP(a)                                                          \
  61         ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
  62 #define RT_ADVANCE(x, n) (x += RT_ROUNDUP((n)->sa_len))
  63 #endif
  64
  65 static void
  66 get_rtaddrs(int addrs, struct sockaddr *sa, struct sockaddr **rti_info)
  67 {
  68         int i;
  69
  70         for (i = 0; i < RTAX_MAX; i++) {
  71                 if (addrs & (1 << i)) {
  72                         rti_info[i] = sa;
  73                         RT_ADVANCE(sa, sa);
  74                 }
  75                 else
  76                         rti_info[i] = NULL;
  77         }
  78 }
  79
  80 struct sockaddr_dl *
  81 if_nametosdl(const char *name)
  82 {
  83         struct ifaddrs *ifap, *ifa;
  84         struct sockaddr_dl *sdl;
  85
  86         if (getifaddrs(&ifap) != 0)
  87                 return (NULL);
  88
  89         for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
  90                 if (strcmp(ifa->ifa_name, name) != 0)
  91                         continue;
  92                 if (ifa->ifa_addr->sa_family != AF_LINK)
  93                         continue;
  94
  95                 sdl = malloc(ifa->ifa_addr->sa_len);
  96                 if (!sdl)
  97                         continue;       /*XXX*/
  98
  99                 memcpy(sdl, ifa->ifa_addr, ifa->ifa_addr->sa_len);
 100                 freeifaddrs(ifap);
 101                 return (sdl);
 102         }
 103
 104         freeifaddrs(ifap);
 105         return (NULL);
 106 }
 107
 108 int
 109 if_getmtu(const char *name)
 110 {
 111         struct ifreq ifr;
 112         int s, mtu;
 113
 114         if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0)
 115                 return 0;
 116
 117         memset(&ifr, 0, sizeof(ifr));
 118         ifr.ifr_addr.sa_family = AF_INET6;
 119         strncpy(ifr.ifr_name, name, sizeof(ifr.ifr_name));
 120         if (ioctl(s, SIOCGIFMTU, &ifr) != -1)
 121                 mtu = ifr.ifr_mtu;
 122         else
 123                 mtu = 0;
 124         close(s);
 125
 126         return mtu;
 127 }
 128
 129 /* give interface index and its old flags, then new flags returned */
 130 int
 131 if_getflags(int ifindex, int oifflags)
 132 {
 133         struct ifreq ifr;
 134         int s;
 135
 136         if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
 137                 syslog(LOG_ERR, "<%s> socket: %m", __func__);
 138                 return (oifflags & ~IFF_UP);
 139         }
 140
 141         memset(&ifr, 0, sizeof(ifr));
 142         if_indextoname(ifindex, ifr.ifr_name);
 143         if (ioctl(s, SIOCGIFFLAGS, &ifr) < 0) {
 144                 syslog(LOG_ERR, "<%s> ioctl:SIOCGIFFLAGS: failed for %s",
 145                        __func__, ifr.ifr_name);
 146                 close(s);
 147                 return (oifflags & ~IFF_UP);
 148         }
 149         close(s);
 150         return (ifr.ifr_flags);
 151 }
 152
 153 #define ROUNDUP8(a) (1 + (((a) - 1) | 7))
 154 int
 155 lladdropt_length(struct sockaddr_dl *sdl)
 156 {
 157         switch (sdl->sdl_type) {
 158         case IFT_ETHER:
 159         case IFT_FDDI:
 160                 return(ROUNDUP8(ETHER_ADDR_LEN + 2));
 161         default:
 162                 return(0);
 163         }
 164 }
 165
 166 void
 167 lladdropt_fill(struct sockaddr_dl *sdl, struct nd_opt_hdr *ndopt)
 168 {
 169         char *addr;
 170
 171         ndopt->nd_opt_type = ND_OPT_SOURCE_LINKADDR; /* fixed */
 172
 173         switch (sdl->sdl_type) {
 174         case IFT_ETHER:
 175         case IFT_FDDI:
 176                 ndopt->nd_opt_len = (ROUNDUP8(ETHER_ADDR_LEN + 2)) >> 3;
 177                 addr = (char *)(ndopt + 1);
 178                 memcpy(addr, LLADDR(sdl), ETHER_ADDR_LEN);
 179                 break;
 180         default:
 181                 syslog(LOG_ERR, "<%s> unsupported link type(%d)",
 182                     __func__, sdl->sdl_type);
 183                 exit(1);
 184         }
 185
 186         return;
 187 }
 188
 189 #define FILTER_MATCH(type, filter) ((0x1 << type) & filter)
 190 #define SIN6(s) ((struct sockaddr_in6 *)(s))
 191 #define SDL(s) ((struct sockaddr_dl *)(s))
 192 char *
 193 get_next_msg(char *buf, char *lim, int ifindex, size_t *lenp, int filter)
 194 {
 195         struct rt_msghdr *rtm;
 196         struct ifa_msghdr *ifam;
 197         struct sockaddr *sa, *dst, *gw, *ifa, *rti_info[RTAX_MAX];
 198
 199         *lenp = 0;
 200         for (rtm = (struct rt_msghdr *)buf;
 201              rtm < (struct rt_msghdr *)lim;
 202              rtm = (struct rt_msghdr *)(((char *)rtm) + rtm->rtm_msglen)) {
 203                 /* just for safety */
 204                 if (!rtm->rtm_msglen) {
 205                         syslog(LOG_WARNING, "<%s> rtm_msglen is 0 "
 206                                 "(buf=%p lim=%p rtm=%p)", __func__,
 207                                 buf, lim, rtm);
 208                         break;
 209                 }
 210                 if (FILTER_MATCH(rtm->rtm_type, filter) == 0) {
 211                         continue;
 212                 }
 213
 214                 switch (rtm->rtm_type) {
 215                 case RTM_GET:
 216                 case RTM_ADD:
 217                 case RTM_DELETE:
 218                         /* address related checks */
 219                         sa = (struct sockaddr *)(rtm + 1);
 220                         get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
 221                         if ((dst = rti_info[RTAX_DST]) == NULL ||
 222                             dst->sa_family != AF_INET6)
 223                                 continue;
 224
 225                         if (IN6_IS_ADDR_LINKLOCAL(&SIN6(dst)->sin6_addr) ||
 226                             IN6_IS_ADDR_MULTICAST(&SIN6(dst)->sin6_addr))
 227                                 continue;
 228
 229                         if ((gw = rti_info[RTAX_GATEWAY]) == NULL ||
 230                             gw->sa_family != AF_LINK)
 231                                 continue;
 232                         if (ifindex && SDL(gw)->sdl_index != ifindex)
 233                                 continue;
 234
 235                         if (rti_info[RTAX_NETMASK] == NULL)
 236                                 continue;
 237
 238                         /* found */
 239                         *lenp = rtm->rtm_msglen;
 240                         return (char *)rtm;
 241                         /* NOTREACHED */
 242                 case RTM_NEWADDR:
 243                 case RTM_DELADDR:
 244                         ifam = (struct ifa_msghdr *)rtm;
 245
 246                         /* address related checks */
 247                         sa = (struct sockaddr *)(ifam + 1);
 248                         get_rtaddrs(ifam->ifam_addrs, sa, rti_info);
 249                         if ((ifa = rti_info[RTAX_IFA]) == NULL ||
 250                             (ifa->sa_family != AF_INET &&
 251                              ifa->sa_family != AF_INET6))
 252                                 continue;
 253
 254                         if (ifa->sa_family == AF_INET6 &&
 255                             (IN6_IS_ADDR_LINKLOCAL(&SIN6(ifa)->sin6_addr) ||
 256                              IN6_IS_ADDR_MULTICAST(&SIN6(ifa)->sin6_addr)))
 257                                 continue;
 258
 259                         if (ifindex && ifam->ifam_index != ifindex)
 260                                 continue;
 261
 262                         /* found */
 263                         *lenp = ifam->ifam_msglen;
 264                         return (char *)rtm;
 265                         /* NOTREACHED */
 266 #ifdef RTM_IFANNOUNCE
 267                 case RTM_IFANNOUNCE:
 268 #endif
 269                 case RTM_IFINFO:
 270                         /* found */
 271                         *lenp = rtm->rtm_msglen;
 272                         return (char *)rtm;
 273                         /* NOTREACHED */
 274                 }
 275         }
 276
 277         return (char *)rtm;
 278 }
 279 #undef FILTER_MATCH
 280
 281 struct in6_addr *
 282 get_addr(char *buf)
 283 {
 284         struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
 285         struct sockaddr *sa, *rti_info[RTAX_MAX];
 286
 287         sa = (struct sockaddr *)(rtm + 1);
 288         get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
 289
 290         return(&SIN6(rti_info[RTAX_DST])->sin6_addr);
 291 }
 292
 293 int
 294 get_rtm_ifindex(char *buf)
 295 {
 296         struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
 297         struct sockaddr *sa, *rti_info[RTAX_MAX];
 298
 299         sa = (struct sockaddr *)(rtm + 1);
 300         get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
 301
 302         return(((struct sockaddr_dl *)rti_info[RTAX_GATEWAY])->sdl_index);
 303 }
 304
 305 int
 306 get_ifm_ifindex(char *buf)
 307 {
 308         struct if_msghdr *ifm = (struct if_msghdr *)buf;
 309
 310         return ((int)ifm->ifm_index);
 311 }
 312
 313 int
 314 get_ifam_ifindex(char *buf)
 315 {
 316         struct ifa_msghdr *ifam = (struct ifa_msghdr *)buf;
 317
 318         return ((int)ifam->ifam_index);
 319 }
 320
 321 int
 322 get_ifm_flags(char *buf)
 323 {
 324         struct if_msghdr *ifm = (struct if_msghdr *)buf;
 325
 326         return (ifm->ifm_flags);
 327 }
 328
 329 #ifdef RTM_IFANNOUNCE
 330 int
 331 get_ifan_ifindex(char *buf)
 332 {
 333         struct if_announcemsghdr *ifan = (struct if_announcemsghdr *)buf;
 334
 335         return ((int)ifan->ifan_index);
 336 }
 337
 338 int
 339 get_ifan_what(char *buf)
 340 {
 341         struct if_announcemsghdr *ifan = (struct if_announcemsghdr *)buf;
 342
 343         return ((int)ifan->ifan_what);
 344 }
 345 #endif
 346
 347 int
 348 get_prefixlen(char *buf)
 349 {
 350         struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
 351         struct sockaddr *sa, *rti_info[RTAX_MAX];
 352         unsigned char *p, *lim;
 353
 354         sa = (struct sockaddr *)(rtm + 1);
 355         get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
 356         sa = rti_info[RTAX_NETMASK];
 357
 358         p = (unsigned char *)(&SIN6(sa)->sin6_addr);
 359         lim = (unsigned char *)sa + sa->sa_len;
 360         return prefixlen(p, lim);
 361 }
 362
 363 int
 364 prefixlen(const unsigned char *p, const unsigned char *lim)
 365 {
 366         int masklen;
 367
 368         for (masklen = 0; p < lim; p++) {
 369                 switch (*p) {
 370                 case 0xff:
 371                         masklen += 8;
 372                         break;
 373                 case 0xfe:
 374                         masklen += 7;
 375                         break;
 376                 case 0xfc:
 377                         masklen += 6;
 378                         break;
 379                 case 0xf8:
 380                         masklen += 5;
 381                         break;
 382                 case 0xf0:
 383                         masklen += 4;
 384                         break;
 385                 case 0xe0:
 386                         masklen += 3;
 387                         break;
 388                 case 0xc0:
 389                         masklen += 2;
 390                         break;
 391                 case 0x80:
 392                         masklen += 1;
 393                         break;
 394                 case 0x00:
 395                         break;
 396                 default:
 397                         return(-1);
 398                 }
 399         }
 400
 401         return(masklen);
 402 }
 403
 404 int
 405 rtmsg_type(char *buf)
 406 {
 407         struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
 408
 409         return(rtm->rtm_type);
 410 }
 411
 412 int
 413 rtmsg_len(char *buf)
 414 {
 415         struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
 416
 417         return(rtm->rtm_msglen);
 418 }