external/bsd/libpcap/dist/fad-gifc.c

   1 /*      $NetBSD: fad-gifc.c,v 1.3 2015/03/31 21:39:42 christos Exp $    */
   2
   3 /* -*- Mode: c; tab-width: 8; indent-tabs-mode: 1; c-basic-offset: 8; -*- */
   4 /*
   5  * Copyright (c) 1994, 1995, 1996, 1997, 1998
   6  *      The Regents of the University of California.  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. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the Computer Systems
  19  *      Engineering Group at Lawrence Berkeley Laboratory.
  20  * 4. Neither the name of the University nor of the Laboratory may be used
  21  *    to endorse or promote products derived from this software without
  22  *    specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  */
  36
  37 #include <sys/cdefs.h>
  38 __RCSID("$NetBSD: fad-gifc.c,v 1.3 2015/03/31 21:39:42 christos Exp $");
  39
  40 #ifdef HAVE_CONFIG_H
  41 #include "config.h"
  42 #endif
  43
  44 #include <sys/param.h>
  45 #include <sys/ioctl.h>
  46 #include <sys/socket.h>
  47 #ifdef HAVE_SYS_SOCKIO_H
  48 #include <sys/sockio.h>
  49 #endif
  50 #include <sys/time.h>                           /* concession to AIX */
  51
  52 struct mbuf;            /* Squelch compiler warnings on some platforms for */
  53 struct rtentry;         /* declarations in <net/if.h> */
  54 #include <net/if.h>
  55 #include <netinet/in.h>
  56
  57 #include <ctype.h>
  58 #include <errno.h>
  59 #include <memory.h>
  60 #include <stdio.h>
  61 #include <stdlib.h>
  62 #include <string.h>
  63 #include <unistd.h>
  64
  65 #include "pcap-int.h"
  66
  67 #ifdef HAVE_OS_PROTO_H
  68 #include "os-proto.h"
  69 #endif
  70
  71 /*
  72  * This is fun.
  73  *
  74  * In older BSD systems, socket addresses were fixed-length, and
  75  * "sizeof (struct sockaddr)" gave the size of the structure.
  76  * All addresses fit within a "struct sockaddr".
  77  *
  78  * In newer BSD systems, the socket address is variable-length, and
  79  * there's an "sa_len" field giving the length of the structure;
  80  * this allows socket addresses to be longer than 2 bytes of family
  81  * and 14 bytes of data.
  82  *
  83  * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553
  84  * variant of the old BSD scheme (with "struct sockaddr_storage" rather
  85  * than "struct sockaddr"), and some use the new BSD scheme.
  86  *
  87  * Some versions of GNU libc use neither scheme, but has an "SA_LEN()"
  88  * macro that determines the size based on the address family.  Other
  89  * versions don't have "SA_LEN()" (as it was in drafts of RFC 2553
  90  * but not in the final version).
  91  *
  92  * We assume that a UNIX that doesn't have "getifaddrs()" and doesn't have
  93  * SIOCGLIFCONF, but has SIOCGIFCONF, uses "struct sockaddr" for the
  94  * address in an entry returned by SIOCGIFCONF.
  95  */
  96 #ifndef SA_LEN
  97 #ifdef HAVE_SOCKADDR_SA_LEN
  98 #define SA_LEN(addr)    ((addr)->sa_len)
  99 #else /* HAVE_SOCKADDR_SA_LEN */
 100 #define SA_LEN(addr)    (sizeof (struct sockaddr))
 101 #endif /* HAVE_SOCKADDR_SA_LEN */
 102 #endif /* SA_LEN */
 103
 104 /*
 105  * This is also fun.
 106  *
 107  * There is no ioctl that returns the amount of space required for all
 108  * the data that SIOCGIFCONF could return, and if a buffer is supplied
 109  * that's not large enough for all the data SIOCGIFCONF could return,
 110  * on at least some platforms it just returns the data that'd fit with
 111  * no indication that there wasn't enough room for all the data, much
 112  * less an indication of how much more room is required.
 113  *
 114  * The only way to ensure that we got all the data is to pass a buffer
 115  * large enough that the amount of space in the buffer *not* filled in
 116  * is greater than the largest possible entry.
 117  *
 118  * We assume that's "sizeof(ifreq.ifr_name)" plus 255, under the assumption
 119  * that no address is more than 255 bytes (on systems where the "sa_len"
 120  * field in a "struct sockaddr" is 1 byte, e.g. newer BSDs, that's the
 121  * case, and addresses are unlikely to be bigger than that in any case).
 122  */
 123 #define MAX_SA_LEN      255
 124
 125 /*
 126  * Get a list of all interfaces that are up and that we can open.
 127  * Returns -1 on error, 0 otherwise.
 128  * The list, as returned through "alldevsp", may be null if no interfaces
 129  * were up and could be opened.
 130  *
 131  * This is the implementation used on platforms that have SIOCGIFCONF but
 132  * don't have any other mechanism for getting a list of interfaces.
 133  *
 134  * XXX - or platforms that have other, better mechanisms but for which
 135  * we don't yet have code to use that mechanism; I think there's a better
 136  * way on Linux, for example, but if that better way is "getifaddrs()",
 137  * we already have that.
 138  */
 139 int
 140 pcap_findalldevs_interfaces(pcap_if_t **alldevsp, char *errbuf)
 141 {
 142         pcap_if_t *devlist = NULL;
 143         register int fd;
 144         register struct ifreq *ifrp, *ifend, *ifnext;
 145         int n;
 146         struct ifconf ifc;
 147         char *buf = NULL;
 148         unsigned buf_size;
 149 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER)
 150         char *p, *q;
 151 #endif
 152         struct ifreq ifrflags, ifrnetmask, ifrbroadaddr, ifrdstaddr;
 153         struct sockaddr *netmask, *broadaddr, *dstaddr;
 154         size_t netmask_size, broadaddr_size, dstaddr_size;
 155         int ret = 0;
 156
 157         /*
 158          * Create a socket from which to fetch the list of interfaces.
 159          */
 160         fd = socket(AF_INET, SOCK_DGRAM, 0);
 161         if (fd < 0) {
 162                 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 163                     "socket: %s", pcap_strerror(errno));
 164                 return (-1);
 165         }
 166
 167         /*
 168          * Start with an 8K buffer, and keep growing the buffer until
 169          * we have more than "sizeof(ifrp->ifr_name) + MAX_SA_LEN"
 170          * bytes left over in the buffer or we fail to get the
 171          * interface list for some reason other than EINVAL (which is
 172          * presumed here to mean "buffer is too small").
 173          */
 174         buf_size = 8192;
 175         for (;;) {
 176                 buf = malloc(buf_size);
 177                 if (buf == NULL) {
 178                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 179                             "malloc: %s", pcap_strerror(errno));
 180                         (void)close(fd);
 181                         return (-1);
 182                 }
 183
 184                 ifc.ifc_len = buf_size;
 185                 ifc.ifc_buf = buf;
 186                 memset(buf, 0, buf_size);
 187                 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0
 188                     && errno != EINVAL) {
 189                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 190                             "SIOCGIFCONF: %s", pcap_strerror(errno));
 191                         (void)close(fd);
 192                         free(buf);
 193                         return (-1);
 194                 }
 195                 if (ifc.ifc_len < buf_size &&
 196                     (buf_size - ifc.ifc_len) > sizeof(ifrp->ifr_name) + MAX_SA_LEN)
 197                         break;
 198                 free(buf);
 199                 buf_size *= 2;
 200         }
 201
 202         ifrp = (struct ifreq *)buf;
 203         ifend = (struct ifreq *)(buf + ifc.ifc_len);
 204
 205         for (; ifrp < ifend; ifrp = ifnext) {
 206                 /*
 207                  * XXX - what if this isn't an IPv4 address?  Can
 208                  * we still get the netmask, etc. with ioctls on
 209                  * an IPv4 socket?
 210                  *
 211                  * The answer is probably platform-dependent, and
 212                  * if the answer is "no" on more than one platform,
 213                  * the way you work around it is probably platform-
 214                  * dependent as well.
 215                  */
 216                 n = SA_LEN(&ifrp->ifr_addr) + sizeof(ifrp->ifr_name);
 217                 if (n < sizeof(*ifrp))
 218                         ifnext = ifrp + 1;
 219                 else
 220                         ifnext = (struct ifreq *)((char *)ifrp + n);
 221
 222                 /*
 223                  * XXX - The 32-bit compatibility layer for Linux on IA-64
 224                  * is slightly broken. It correctly converts the structures
 225                  * to and from kernel land from 64 bit to 32 bit but
 226                  * doesn't update ifc.ifc_len, leaving it larger than the
 227                  * amount really used. This means we read off the end
 228                  * of the buffer and encounter an interface with an
 229                  * "empty" name. Since this is highly unlikely to ever
 230                  * occur in a valid case we can just finish looking for
 231                  * interfaces if we see an empty name.
 232                  */
 233                 if (!(*ifrp->ifr_name))
 234                         break;
 235
 236                 /*
 237                  * Skip entries that begin with "dummy".
 238                  * XXX - what are these?  Is this Linux-specific?
 239                  * Are there platforms on which we shouldn't do this?
 240                  */
 241                 if (strncmp(ifrp->ifr_name, "dummy", 5) == 0)
 242                         continue;
 243
 244                 /*
 245                  * Get the flags for this interface.
 246                  */
 247                 strncpy(ifrflags.ifr_name, ifrp->ifr_name,
 248                     sizeof(ifrflags.ifr_name));
 249                 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) {
 250                         if (errno == ENXIO)
 251                                 continue;
 252                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 253                             "SIOCGIFFLAGS: %.*s: %s",
 254                             (int)sizeof(ifrflags.ifr_name),
 255                             ifrflags.ifr_name,
 256                             pcap_strerror(errno));
 257                         ret = -1;
 258                         break;
 259                 }
 260
 261                 /*
 262                  * Get the netmask for this address on this interface.
 263                  */
 264                 strncpy(ifrnetmask.ifr_name, ifrp->ifr_name,
 265                     sizeof(ifrnetmask.ifr_name));
 266                 memcpy(&ifrnetmask.ifr_addr, &ifrp->ifr_addr,
 267                     sizeof(ifrnetmask.ifr_addr));
 268                 if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifrnetmask) < 0) {
 269                         if (errno == EADDRNOTAVAIL) {
 270                                 /*
 271                                  * Not available.
 272                                  */
 273                                 netmask = NULL;
 274                                 netmask_size = 0;
 275                         } else {
 276                                 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 277                                     "SIOCGIFNETMASK: %.*s: %s",
 278                                     (int)sizeof(ifrnetmask.ifr_name),
 279                                     ifrnetmask.ifr_name,
 280                                     pcap_strerror(errno));
 281                                 ret = -1;
 282                                 break;
 283                         }
 284                 } else {
 285                         netmask = &ifrnetmask.ifr_addr;
 286                         netmask_size = SA_LEN(netmask);
 287                 }
 288
 289                 /*
 290                  * Get the broadcast address for this address on this
 291                  * interface (if any).
 292                  */
 293                 if (ifrflags.ifr_flags & IFF_BROADCAST) {
 294                         strncpy(ifrbroadaddr.ifr_name, ifrp->ifr_name,
 295                             sizeof(ifrbroadaddr.ifr_name));
 296                         memcpy(&ifrbroadaddr.ifr_addr, &ifrp->ifr_addr,
 297                             sizeof(ifrbroadaddr.ifr_addr));
 298                         if (ioctl(fd, SIOCGIFBRDADDR,
 299                             (char *)&ifrbroadaddr) < 0) {
 300                                 if (errno == EADDRNOTAVAIL) {
 301                                         /*
 302                                          * Not available.
 303                                          */
 304                                         broadaddr = NULL;
 305                                         broadaddr_size = 0;
 306                                 } else {
 307                                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 308                                             "SIOCGIFBRDADDR: %.*s: %s",
 309                                             (int)sizeof(ifrbroadaddr.ifr_name),
 310                                             ifrbroadaddr.ifr_name,
 311                                             pcap_strerror(errno));
 312                                         ret = -1;
 313                                         break;
 314                                 }
 315                         } else {
 316                                 broadaddr = &ifrbroadaddr.ifr_broadaddr;
 317                                 broadaddr_size = SA_LEN(broadaddr);
 318                         }
 319                 } else {
 320                         /*
 321                          * Not a broadcast interface, so no broadcast
 322                          * address.
 323                          */
 324                         broadaddr = NULL;
 325                         broadaddr_size = 0;
 326                 }
 327
 328                 /*
 329                  * Get the destination address for this address on this
 330                  * interface (if any).
 331                  */
 332                 if (ifrflags.ifr_flags & IFF_POINTOPOINT) {
 333                         strncpy(ifrdstaddr.ifr_name, ifrp->ifr_name,
 334                             sizeof(ifrdstaddr.ifr_name));
 335                         memcpy(&ifrdstaddr.ifr_addr, &ifrp->ifr_addr,
 336                             sizeof(ifrdstaddr.ifr_addr));
 337                         if (ioctl(fd, SIOCGIFDSTADDR,
 338                             (char *)&ifrdstaddr) < 0) {
 339                                 if (errno == EADDRNOTAVAIL) {
 340                                         /*
 341                                          * Not available.
 342                                          */
 343                                         dstaddr = NULL;
 344                                         dstaddr_size = 0;
 345                                 } else {
 346                                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 347                                             "SIOCGIFDSTADDR: %.*s: %s",
 348                                             (int)sizeof(ifrdstaddr.ifr_name),
 349                                             ifrdstaddr.ifr_name,
 350                                             pcap_strerror(errno));
 351                                         ret = -1;
 352                                         break;
 353                                 }
 354                         } else {
 355                                 dstaddr = &ifrdstaddr.ifr_dstaddr;
 356                                 dstaddr_size = SA_LEN(dstaddr);
 357                         }
 358                 } else {
 359                         /*
 360                          * Not a point-to-point interface, so no destination
 361                          * address.
 362                          */
 363                         dstaddr = NULL;
 364                         dstaddr_size = 0;
 365                 }
 366
 367 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER)
 368                 /*
 369                  * If this entry has a colon followed by a number at
 370                  * the end, it's a logical interface.  Those are just
 371                  * the way you assign multiple IP addresses to a real
 372                  * interface, so an entry for a logical interface should
 373                  * be treated like the entry for the real interface;
 374                  * we do that by stripping off the ":" and the number.
 375                  */
 376                 p = strchr(ifrp->ifr_name, ':');
 377                 if (p != NULL) {
 378                         /*
 379                          * We have a ":"; is it followed by a number?
 380                          */
 381                         q = p + 1;
 382                         while (isdigit((unsigned char)*q))
 383                                 q++;
 384                         if (*q == '\0') {
 385                                 /*
 386                                  * All digits after the ":" until the end.
 387                                  * Strip off the ":" and everything after
 388                                  * it.
 389                                  */
 390                                 *p = '\0';
 391                         }
 392                 }
 393 #endif
 394
 395                 /*
 396                  * Add information for this address to the list.
 397                  */
 398                 if (add_addr_to_iflist(&devlist, ifrp->ifr_name,
 399                     ifrflags.ifr_flags, &ifrp->ifr_addr,
 400                     SA_LEN(&ifrp->ifr_addr), netmask, netmask_size,
 401                     broadaddr, broadaddr_size, dstaddr, dstaddr_size,
 402                     errbuf) < 0) {
 403                         ret = -1;
 404                         break;
 405                 }
 406         }
 407         free(buf);
 408         (void)close(fd);
 409
 410         if (ret == -1) {
 411                 /*
 412                  * We had an error; free the list we've been constructing.
 413                  */
 414                 if (devlist != NULL) {
 415                         pcap_freealldevs(devlist);
 416                         devlist = NULL;
 417                 }
 418         }
 419
 420         *alldevsp = devlist;
 421         return (ret);
 422 }