contrib/libpcap/fad-gifc.c

   1 /* -*- Mode: c; tab-width: 8; indent-tabs-mode: 1; c-basic-offset: 8; -*- */
   2 /*
   3  * Copyright (c) 1994, 1995, 1996, 1997, 1998
   4  *      The Regents of the University of California.  All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  * 3. All advertising materials mentioning features or use of this software
  15  *    must display the following acknowledgement:
  16  *      This product includes software developed by the Computer Systems
  17  *      Engineering Group at Lawrence Berkeley Laboratory.
  18  * 4. Neither the name of the University nor of the Laboratory may be used
  19  *    to endorse or promote products derived from this software without
  20  *    specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 #ifndef lint
  36 static const char rcsid[] _U_ =
  37     "@(#) $Header: /tcpdump/master/libpcap/fad-gifc.c,v 1.8.2.2 2005/06/29 06:43:31 guy Exp $ (LBL)";
  38 #endif
  39
  40 #ifdef HAVE_CONFIG_H
  41 #include "config.h"
  42 #endif
  43
  44 #include <sys/param.h>
  45 #include <sys/file.h>
  46 #include <sys/ioctl.h>
  47 #include <sys/socket.h>
  48 #ifdef HAVE_SYS_SOCKIO_H
  49 #include <sys/sockio.h>
  50 #endif
  51 #include <sys/time.h>                           /* concession to AIX */
  52
  53 struct mbuf;            /* Squelch compiler warnings on some platforms for */
  54 struct rtentry;         /* declarations in <net/if.h> */
  55 #include <net/if.h>
  56 #include <netinet/in.h>
  57
  58 #include <ctype.h>
  59 #include <errno.h>
  60 #include <memory.h>
  61 #include <stdio.h>
  62 #include <stdlib.h>
  63 #include <string.h>
  64 #include <unistd.h>
  65
  66 #include "pcap-int.h"
  67
  68 #ifdef HAVE_OS_PROTO_H
  69 #include "os-proto.h"
  70 #endif
  71
  72 /*
  73  * This is fun.
  74  *
  75  * In older BSD systems, socket addresses were fixed-length, and
  76  * "sizeof (struct sockaddr)" gave the size of the structure.
  77  * All addresses fit within a "struct sockaddr".
  78  *
  79  * In newer BSD systems, the socket address is variable-length, and
  80  * there's an "sa_len" field giving the length of the structure;
  81  * this allows socket addresses to be longer than 2 bytes of family
  82  * and 14 bytes of data.
  83  *
  84  * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553
  85  * variant of the old BSD scheme (with "struct sockaddr_storage" rather
  86  * than "struct sockaddr"), and some use the new BSD scheme.
  87  *
  88  * Some versions of GNU libc use neither scheme, but has an "SA_LEN()"
  89  * macro that determines the size based on the address family.  Other
  90  * versions don't have "SA_LEN()" (as it was in drafts of RFC 2553
  91  * but not in the final version).
  92  *
  93  * We assume that a UNIX that doesn't have "getifaddrs()" and doesn't have
  94  * SIOCGLIFCONF, but has SIOCGIFCONF, uses "struct sockaddr" for the
  95  * address in an entry returned by SIOCGIFCONF.
  96  */
  97 #ifndef SA_LEN
  98 #ifdef HAVE_SOCKADDR_SA_LEN
  99 #define SA_LEN(addr)    ((addr)->sa_len)
 100 #else /* HAVE_SOCKADDR_SA_LEN */
 101 #define SA_LEN(addr)    (sizeof (struct sockaddr))
 102 #endif /* HAVE_SOCKADDR_SA_LEN */
 103 #endif /* SA_LEN */
 104
 105 /*
 106  * This is also fun.
 107  *
 108  * There is no ioctl that returns the amount of space required for all
 109  * the data that SIOCGIFCONF could return, and if a buffer is supplied
 110  * that's not large enough for all the data SIOCGIFCONF could return,
 111  * on at least some platforms it just returns the data that'd fit with
 112  * no indication that there wasn't enough room for all the data, much
 113  * less an indication of how much more room is required.
 114  *
 115  * The only way to ensure that we got all the data is to pass a buffer
 116  * large enough that the amount of space in the buffer *not* filled in
 117  * is greater than the largest possible entry.
 118  *
 119  * We assume that's "sizeof(ifreq.ifr_name)" plus 255, under the assumption
 120  * that no address is more than 255 bytes (on systems where the "sa_len"
 121  * field in a "struct sockaddr" is 1 byte, e.g. newer BSDs, that's the
 122  * case, and addresses are unlikely to be bigger than that in any case).
 123  */
 124 #define MAX_SA_LEN      255
 125
 126 #ifdef HAVE_PROC_NET_DEV
 127 /*
 128  * Get from "/proc/net/dev" all interfaces listed there; if they're
 129  * already in the list of interfaces we have, that won't add another
 130  * instance, but if they're not, that'll add them.
 131  *
 132  * We don't bother getting any addresses for them; it appears you can't
 133  * use SIOCGIFADDR on Linux to get IPv6 addresses for interfaces, and,
 134  * although some other types of addresses can be fetched with SIOCGIFADDR,
 135  * we don't bother with them for now.
 136  *
 137  * We also don't fail if we couldn't open "/proc/net/dev"; we just leave
 138  * the list of interfaces as is.
 139  */
 140 static int
 141 scan_proc_net_dev(pcap_if_t **devlistp, int fd, char *errbuf)
 142 {
 143         FILE *proc_net_f;
 144         char linebuf[512];
 145         int linenum;
 146         unsigned char *p;
 147         char name[512]; /* XXX - pick a size */
 148         char *q, *saveq;
 149         struct ifreq ifrflags;
 150         int ret = 0;
 151
 152         proc_net_f = fopen("/proc/net/dev", "r");
 153         if (proc_net_f == NULL)
 154                 return (0);
 155
 156         for (linenum = 1;
 157             fgets(linebuf, sizeof linebuf, proc_net_f) != NULL; linenum++) {
 158                 /*
 159                  * Skip the first two lines - they're headers.
 160                  */
 161                 if (linenum <= 2)
 162                         continue;
 163
 164                 p = &linebuf[0];
 165
 166                 /*
 167                  * Skip leading white space.
 168                  */
 169                 while (*p != '\0' && isspace(*p))
 170                         p++;
 171                 if (*p == '\0' || *p == '\n')
 172                         continue;       /* blank line */
 173
 174                 /*
 175                  * Get the interface name.
 176                  */
 177                 q = &name[0];
 178                 while (*p != '\0' && !isspace(*p)) {
 179                         if (*p == ':') {
 180                                 /*
 181                                  * This could be the separator between a
 182                                  * name and an alias number, or it could be
 183                                  * the separator between a name with no
 184                                  * alias number and the next field.
 185                                  *
 186                                  * If there's a colon after digits, it
 187                                  * separates the name and the alias number,
 188                                  * otherwise it separates the name and the
 189                                  * next field.
 190                                  */
 191                                 saveq = q;
 192                                 while (isdigit(*p))
 193                                         *q++ = *p++;
 194                                 if (*p != ':') {
 195                                         /*
 196                                          * That was the next field,
 197                                          * not the alias number.
 198                                          */
 199                                         q = saveq;
 200                                 }
 201                                 break;
 202                         } else
 203                                 *q++ = *p++;
 204                 }
 205                 *q = '\0';
 206
 207                 /*
 208                  * Get the flags for this interface, and skip it if
 209                  * it's not up.
 210                  */
 211                 strncpy(ifrflags.ifr_name, name, sizeof(ifrflags.ifr_name));
 212                 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) {
 213                         if (errno == ENXIO)
 214                                 continue;
 215                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 216                             "SIOCGIFFLAGS: %.*s: %s",
 217                             (int)sizeof(ifrflags.ifr_name),
 218                             ifrflags.ifr_name,
 219                             pcap_strerror(errno));
 220                         ret = -1;
 221                         break;
 222                 }
 223                 if (!(ifrflags.ifr_flags & IFF_UP))
 224                         continue;
 225
 226                 /*
 227                  * Add an entry for this interface, with no addresses.
 228                  */
 229                 if (pcap_add_if(devlistp, name, ifrflags.ifr_flags, NULL,
 230                     errbuf) == -1) {
 231                         /*
 232                          * Failure.
 233                          */
 234                         ret = -1;
 235                         break;
 236                 }
 237         }
 238         if (ret != -1) {
 239                 /*
 240                  * Well, we didn't fail for any other reason; did we
 241                  * fail due to an error reading the file?
 242                  */
 243                 if (ferror(proc_net_f)) {
 244                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 245                             "Error reading /proc/net/dev: %s",
 246                             pcap_strerror(errno));
 247                         ret = -1;
 248                 }
 249         }
 250
 251         (void)fclose(proc_net_f);
 252         return (ret);
 253 }
 254 #endif /* HAVE_PROC_NET_DEV */
 255
 256 /*
 257  * Get a list of all interfaces that are up and that we can open.
 258  * Returns -1 on error, 0 otherwise.
 259  * The list, as returned through "alldevsp", may be null if no interfaces
 260  * were up and could be opened.
 261  *
 262  * This is the implementation used on platforms that have SIOCGIFCONF but
 263  * don't have any other mechanism for getting a list of interfaces.
 264  *
 265  * XXX - or platforms that have other, better mechanisms but for which
 266  * we don't yet have code to use that mechanism; I think there's a better
 267  * way on Linux, for example.
 268  */
 269 int
 270 pcap_findalldevs(pcap_if_t **alldevsp, char *errbuf)
 271 {
 272         pcap_if_t *devlist = NULL;
 273         register int fd;
 274         register struct ifreq *ifrp, *ifend, *ifnext;
 275         int n;
 276         struct ifconf ifc;
 277         char *buf = NULL;
 278         unsigned buf_size;
 279 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER)
 280         char *p, *q;
 281 #endif
 282         struct ifreq ifrflags, ifrnetmask, ifrbroadaddr, ifrdstaddr;
 283         struct sockaddr *netmask, *broadaddr, *dstaddr;
 284         size_t netmask_size, broadaddr_size, dstaddr_size;
 285         int ret = 0;
 286
 287         /*
 288          * Create a socket from which to fetch the list of interfaces.
 289          */
 290         fd = socket(AF_INET, SOCK_DGRAM, 0);
 291         if (fd < 0) {
 292                 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 293                     "socket: %s", pcap_strerror(errno));
 294                 return (-1);
 295         }
 296
 297         /*
 298          * Start with an 8K buffer, and keep growing the buffer until
 299          * we have more than "sizeof(ifrp->ifr_name) + MAX_SA_LEN"
 300          * bytes left over in the buffer or we fail to get the
 301          * interface list for some reason other than EINVAL (which is
 302          * presumed here to mean "buffer is too small").
 303          */
 304         buf_size = 8192;
 305         for (;;) {
 306                 buf = malloc(buf_size);
 307                 if (buf == NULL) {
 308                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 309                             "malloc: %s", pcap_strerror(errno));
 310                         (void)close(fd);
 311                         return (-1);
 312                 }
 313
 314                 ifc.ifc_len = buf_size;
 315                 ifc.ifc_buf = buf;
 316                 memset(buf, 0, buf_size);
 317                 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0
 318                     && errno != EINVAL) {
 319                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 320                             "SIOCGIFCONF: %s", pcap_strerror(errno));
 321                         (void)close(fd);
 322                         free(buf);
 323                         return (-1);
 324                 }
 325                 if (ifc.ifc_len < buf_size &&
 326                     (buf_size - ifc.ifc_len) > sizeof(ifrp->ifr_name) + MAX_SA_LEN)
 327                         break;
 328                 free(buf);
 329                 buf_size *= 2;
 330         }
 331
 332         ifrp = (struct ifreq *)buf;
 333         ifend = (struct ifreq *)(buf + ifc.ifc_len);
 334
 335         for (; ifrp < ifend; ifrp = ifnext) {
 336                 /*
 337                  * XXX - what if this isn't an IPv4 address?  Can
 338                  * we still get the netmask, etc. with ioctls on
 339                  * an IPv4 socket?
 340                  *
 341                  * The answer is probably platform-dependent, and
 342                  * if the answer is "no" on more than one platform,
 343                  * the way you work around it is probably platform-
 344                  * dependent as well.
 345                  */
 346                 n = SA_LEN(&ifrp->ifr_addr) + sizeof(ifrp->ifr_name);
 347                 if (n < sizeof(*ifrp))
 348                         ifnext = ifrp + 1;
 349                 else
 350                         ifnext = (struct ifreq *)((char *)ifrp + n);
 351
 352                 /*
 353                  * XXX - The 32-bit compatibility layer for Linux on IA-64
 354                  * is slightly broken. It correctly converts the structures
 355                  * to and from kernel land from 64 bit to 32 bit but
 356                  * doesn't update ifc.ifc_len, leaving it larger than the
 357                  * amount really used. This means we read off the end
 358                  * of the buffer and encounter an interface with an
 359                  * "empty" name. Since this is highly unlikely to ever
 360                  * occur in a valid case we can just finish looking for
 361                  * interfaces if we see an empty name.
 362                  */
 363                 if (!(*ifrp->ifr_name))
 364                         break;
 365
 366                 /*
 367                  * Skip entries that begin with "dummy".
 368                  * XXX - what are these?  Is this Linux-specific?
 369                  * Are there platforms on which we shouldn't do this?
 370                  */
 371                 if (strncmp(ifrp->ifr_name, "dummy", 5) == 0)
 372                         continue;
 373
 374                 /*
 375                  * Get the flags for this interface, and skip it if it's
 376                  * not up.
 377                  */
 378                 strncpy(ifrflags.ifr_name, ifrp->ifr_name,
 379                     sizeof(ifrflags.ifr_name));
 380                 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) {
 381                         if (errno == ENXIO)
 382                                 continue;
 383                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 384                             "SIOCGIFFLAGS: %.*s: %s",
 385                             (int)sizeof(ifrflags.ifr_name),
 386                             ifrflags.ifr_name,
 387                             pcap_strerror(errno));
 388                         ret = -1;
 389                         break;
 390                 }
 391                 if (!(ifrflags.ifr_flags & IFF_UP))
 392                         continue;
 393
 394                 /*
 395                  * Get the netmask for this address on this interface.
 396                  */
 397                 strncpy(ifrnetmask.ifr_name, ifrp->ifr_name,
 398                     sizeof(ifrnetmask.ifr_name));
 399                 memcpy(&ifrnetmask.ifr_addr, &ifrp->ifr_addr,
 400                     sizeof(ifrnetmask.ifr_addr));
 401                 if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifrnetmask) < 0) {
 402                         if (errno == EADDRNOTAVAIL) {
 403                                 /*
 404                                  * Not available.
 405                                  */
 406                                 netmask = NULL;
 407                                 netmask_size = 0;
 408                         } else {
 409                                 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 410                                     "SIOCGIFNETMASK: %.*s: %s",
 411                                     (int)sizeof(ifrnetmask.ifr_name),
 412                                     ifrnetmask.ifr_name,
 413                                     pcap_strerror(errno));
 414                                 ret = -1;
 415                                 break;
 416                         }
 417                 } else {
 418                         netmask = &ifrnetmask.ifr_addr;
 419                         netmask_size = SA_LEN(netmask);
 420                 }
 421
 422                 /*
 423                  * Get the broadcast address for this address on this
 424                  * interface (if any).
 425                  */
 426                 if (ifrflags.ifr_flags & IFF_BROADCAST) {
 427                         strncpy(ifrbroadaddr.ifr_name, ifrp->ifr_name,
 428                             sizeof(ifrbroadaddr.ifr_name));
 429                         memcpy(&ifrbroadaddr.ifr_addr, &ifrp->ifr_addr,
 430                             sizeof(ifrbroadaddr.ifr_addr));
 431                         if (ioctl(fd, SIOCGIFBRDADDR,
 432                             (char *)&ifrbroadaddr) < 0) {
 433                                 if (errno == EADDRNOTAVAIL) {
 434                                         /*
 435                                          * Not available.
 436                                          */
 437                                         broadaddr = NULL;
 438                                         broadaddr_size = 0;
 439                                 } else {
 440                                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 441                                             "SIOCGIFBRDADDR: %.*s: %s",
 442                                             (int)sizeof(ifrbroadaddr.ifr_name),
 443                                             ifrbroadaddr.ifr_name,
 444                                             pcap_strerror(errno));
 445                                         ret = -1;
 446                                         break;
 447                                 }
 448                         } else {
 449                                 broadaddr = &ifrbroadaddr.ifr_broadaddr;
 450                                 broadaddr_size = SA_LEN(broadaddr);
 451                         }
 452                 } else {
 453                         /*
 454                          * Not a broadcast interface, so no broadcast
 455                          * address.
 456                          */
 457                         broadaddr = NULL;
 458                         broadaddr_size = 0;
 459                 }
 460
 461                 /*
 462                  * Get the destination address for this address on this
 463                  * interface (if any).
 464                  */
 465                 if (ifrflags.ifr_flags & IFF_POINTOPOINT) {
 466                         strncpy(ifrdstaddr.ifr_name, ifrp->ifr_name,
 467                             sizeof(ifrdstaddr.ifr_name));
 468                         memcpy(&ifrdstaddr.ifr_addr, &ifrp->ifr_addr,
 469                             sizeof(ifrdstaddr.ifr_addr));
 470                         if (ioctl(fd, SIOCGIFDSTADDR,
 471                             (char *)&ifrdstaddr) < 0) {
 472                                 if (errno == EADDRNOTAVAIL) {
 473                                         /*
 474                                          * Not available.
 475                                          */
 476                                         dstaddr = NULL;
 477                                         dstaddr_size = 0;
 478                                 } else {
 479                                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 480                                             "SIOCGIFDSTADDR: %.*s: %s",
 481                                             (int)sizeof(ifrdstaddr.ifr_name),
 482                                             ifrdstaddr.ifr_name,
 483                                             pcap_strerror(errno));
 484                                         ret = -1;
 485                                         break;
 486                                 }
 487                         } else {
 488                                 dstaddr = &ifrdstaddr.ifr_dstaddr;
 489                                 dstaddr_size = SA_LEN(dstaddr);
 490                         }
 491                 } else {
 492                         /*
 493                          * Not a point-to-point interface, so no destination
 494                          * address.
 495                          */
 496                         dstaddr = NULL;
 497                         dstaddr_size = 0;
 498                 }
 499
 500 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER)
 501                 /*
 502                  * If this entry has a colon followed by a number at
 503                  * the end, it's a logical interface.  Those are just
 504                  * the way you assign multiple IP addresses to a real
 505                  * interface, so an entry for a logical interface should
 506                  * be treated like the entry for the real interface;
 507                  * we do that by stripping off the ":" and the number.
 508                  */
 509                 p = strchr(ifrp->ifr_name, ':');
 510                 if (p != NULL) {
 511                         /*
 512                          * We have a ":"; is it followed by a number?
 513                          */
 514                         q = p + 1;
 515                         while (isdigit((unsigned char)*q))
 516                                 q++;
 517                         if (*q == '\0') {
 518                                 /*
 519                                  * All digits after the ":" until the end.
 520                                  * Strip off the ":" and everything after
 521                                  * it.
 522                                  */
 523                                 *p = '\0';
 524                         }
 525                 }
 526 #endif
 527
 528                 /*
 529                  * Add information for this address to the list.
 530                  */
 531                 if (add_addr_to_iflist(&devlist, ifrp->ifr_name,
 532                     ifrflags.ifr_flags, &ifrp->ifr_addr,
 533                     SA_LEN(&ifrp->ifr_addr), netmask, netmask_size,
 534                     broadaddr, broadaddr_size, dstaddr, dstaddr_size,
 535                     errbuf) < 0) {
 536                         ret = -1;
 537                         break;
 538                 }
 539         }
 540         free(buf);
 541
 542 #ifdef HAVE_PROC_NET_DEV
 543         if (ret != -1) {
 544                 /*
 545                  * We haven't had any errors yet; now read "/proc/net/dev",
 546                  * and add to the list of interfaces all interfaces listed
 547                  * there that we don't already have, because, on Linux,
 548                  * SIOCGIFCONF reports only interfaces with IPv4 addresses,
 549                  * so you need to read "/proc/net/dev" to get the names of
 550                  * the rest of the interfaces.
 551                  */
 552                 ret = scan_proc_net_dev(&devlist, fd, errbuf);
 553         }
 554 #endif
 555         (void)close(fd);
 556
 557         if (ret != -1) {
 558                 /*
 559                  * We haven't had any errors yet; do any platform-specific
 560                  * operations to add devices.
 561                  */
 562                 if (pcap_platform_finddevs(&devlist, errbuf) < 0)
 563                         ret = -1;
 564         }
 565
 566         if (ret == -1) {
 567                 /*
 568                  * We had an error; free the list we've been constructing.
 569                  */
 570                 if (devlist != NULL) {
 571                         pcap_freealldevs(devlist);
 572                         devlist = NULL;
 573                 }
 574         }
 575
 576         *alldevsp = devlist;
 577         return (ret);
 578 }