The Tcpdump Group git mirrors - libpcap/blob - 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 1.11.2.1 2008-08-06 07:35:01 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/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 #ifdef HAVE_PROC_NET_DEV
 126 /*
 127  * Get from "/proc/net/dev" all interfaces listed there; if they're
 128  * already in the list of interfaces we have, that won't add another
 129  * instance, but if they're not, that'll add them.
 130  *
 131  * We don't bother getting any addresses for them; it appears you can't
 132  * use SIOCGIFADDR on Linux to get IPv6 addresses for interfaces, and,
 133  * although some other types of addresses can be fetched with SIOCGIFADDR,
 134  * we don't bother with them for now.
 135  *
 136  * We also don't fail if we couldn't open "/proc/net/dev"; we just leave
 137  * the list of interfaces as is.
 138  */
 139 static int
 140 scan_proc_net_dev(pcap_if_t **devlistp, int fd, char *errbuf)
 141 {
 142         FILE *proc_net_f;
 143         char linebuf[512];
 144         int linenum;
 145         unsigned char *p;
 146         char name[512]; /* XXX - pick a size */
 147         char *q, *saveq;
 148         struct ifreq ifrflags;
 149         int ret = 0;
 150
 151         proc_net_f = fopen("/proc/net/dev", "r");
 152         if (proc_net_f == NULL)
 153                 return (0);
 154
 155         for (linenum = 1;
 156             fgets(linebuf, sizeof linebuf, proc_net_f) != NULL; linenum++) {
 157                 /*
 158                  * Skip the first two lines - they're headers.
 159                  */
 160                 if (linenum <= 2)
 161                         continue;
 162
 163                 p = &linebuf[0];
 164
 165                 /*
 166                  * Skip leading white space.
 167                  */
 168                 while (*p != '\0' && isspace(*p))
 169                         p++;
 170                 if (*p == '\0' || *p == '\n')
 171                         continue;       /* blank line */
 172
 173                 /*
 174                  * Get the interface name.
 175                  */
 176                 q = &name[0];
 177                 while (*p != '\0' && !isspace(*p)) {
 178                         if (*p == ':') {
 179                                 /*
 180                                  * This could be the separator between a
 181                                  * name and an alias number, or it could be
 182                                  * the separator between a name with no
 183                                  * alias number and the next field.
 184                                  *
 185                                  * If there's a colon after digits, it
 186                                  * separates the name and the alias number,
 187                                  * otherwise it separates the name and the
 188                                  * next field.
 189                                  */
 190                                 saveq = q;
 191                                 while (isdigit(*p))
 192                                         *q++ = *p++;
 193                                 if (*p != ':') {
 194                                         /*
 195                                          * That was the next field,
 196                                          * not the alias number.
 197                                          */
 198                                         q = saveq;
 199                                 }
 200                                 break;
 201                         } else
 202                                 *q++ = *p++;
 203                 }
 204                 *q = '\0';
 205
 206                 /*
 207                  * Get the flags for this interface, and skip it if
 208                  * it's not up.
 209                  */
 210                 strncpy(ifrflags.ifr_name, name, sizeof(ifrflags.ifr_name));
 211                 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) {
 212                         if (errno == ENXIO)
 213                                 continue;
 214                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 215                             "SIOCGIFFLAGS: %.*s: %s",
 216                             (int)sizeof(ifrflags.ifr_name),
 217                             ifrflags.ifr_name,
 218                             pcap_strerror(errno));
 219                         ret = -1;
 220                         break;
 221                 }
 222                 if (!(ifrflags.ifr_flags & IFF_UP))
 223                         continue;
 224
 225                 /*
 226                  * Add an entry for this interface, with no addresses.
 227                  */
 228                 if (pcap_add_if(devlistp, name, ifrflags.ifr_flags, NULL,
 229                     errbuf) == -1) {
 230                         /*
 231                          * Failure.
 232                          */
 233                         ret = -1;
 234                         break;
 235                 }
 236         }
 237         if (ret != -1) {
 238                 /*
 239                  * Well, we didn't fail for any other reason; did we
 240                  * fail due to an error reading the file?
 241                  */
 242                 if (ferror(proc_net_f)) {
 243                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 244                             "Error reading /proc/net/dev: %s",
 245                             pcap_strerror(errno));
 246                         ret = -1;
 247                 }
 248         }
 249
 250         (void)fclose(proc_net_f);
 251         return (ret);
 252 }
 253 #endif /* HAVE_PROC_NET_DEV */
 254
 255 /*
 256  * Get a list of all interfaces that are up and that we can open.
 257  * Returns -1 on error, 0 otherwise.
 258  * The list, as returned through "alldevsp", may be null if no interfaces
 259  * were up and could be opened.
 260  *
 261  * This is the implementation used on platforms that have SIOCGIFCONF but
 262  * don't have any other mechanism for getting a list of interfaces.
 263  *
 264  * XXX - or platforms that have other, better mechanisms but for which
 265  * we don't yet have code to use that mechanism; I think there's a better
 266  * way on Linux, for example.
 267  */
 268 int
 269 pcap_findalldevs(pcap_if_t **alldevsp, char *errbuf)
 270 {
 271         pcap_if_t *devlist = NULL;
 272         register int fd;
 273         register struct ifreq *ifrp, *ifend, *ifnext;
 274         int n;
 275         struct ifconf ifc;
 276         char *buf = NULL;
 277         unsigned buf_size;
 278 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER)
 279         char *p, *q;
 280 #endif
 281         struct ifreq ifrflags, ifrnetmask, ifrbroadaddr, ifrdstaddr;
 282         struct sockaddr *netmask, *broadaddr, *dstaddr;
 283         size_t netmask_size, broadaddr_size, dstaddr_size;
 284         int ret = 0;
 285
 286         /*
 287          * Create a socket from which to fetch the list of interfaces.
 288          */
 289         fd = socket(AF_INET, SOCK_DGRAM, 0);
 290         if (fd < 0) {
 291                 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 292                     "socket: %s", pcap_strerror(errno));
 293                 return (-1);
 294         }
 295
 296         /*
 297          * Start with an 8K buffer, and keep growing the buffer until
 298          * we have more than "sizeof(ifrp->ifr_name) + MAX_SA_LEN"
 299          * bytes left over in the buffer or we fail to get the
 300          * interface list for some reason other than EINVAL (which is
 301          * presumed here to mean "buffer is too small").
 302          */
 303         buf_size = 8192;
 304         for (;;) {
 305                 buf = malloc(buf_size);
 306                 if (buf == NULL) {
 307                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 308                             "malloc: %s", pcap_strerror(errno));
 309                         (void)close(fd);
 310                         return (-1);
 311                 }
 312
 313                 ifc.ifc_len = buf_size;
 314                 ifc.ifc_buf = buf;
 315                 memset(buf, 0, buf_size);
 316                 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0
 317                     && errno != EINVAL) {
 318                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 319                             "SIOCGIFCONF: %s", pcap_strerror(errno));
 320                         (void)close(fd);
 321                         free(buf);
 322                         return (-1);
 323                 }
 324                 if (ifc.ifc_len < buf_size &&
 325                     (buf_size - ifc.ifc_len) > sizeof(ifrp->ifr_name) + MAX_SA_LEN)
 326                         break;
 327                 free(buf);
 328                 buf_size *= 2;
 329         }
 330
 331         ifrp = (struct ifreq *)buf;
 332         ifend = (struct ifreq *)(buf + ifc.ifc_len);
 333
 334         for (; ifrp < ifend; ifrp = ifnext) {
 335                 /*
 336                  * XXX - what if this isn't an IPv4 address?  Can
 337                  * we still get the netmask, etc. with ioctls on
 338                  * an IPv4 socket?
 339                  *
 340                  * The answer is probably platform-dependent, and
 341                  * if the answer is "no" on more than one platform,
 342                  * the way you work around it is probably platform-
 343                  * dependent as well.
 344                  */
 345                 n = SA_LEN(&ifrp->ifr_addr) + sizeof(ifrp->ifr_name);
 346                 if (n < sizeof(*ifrp))
 347                         ifnext = ifrp + 1;
 348                 else
 349                         ifnext = (struct ifreq *)((char *)ifrp + n);
 350
 351                 /*
 352                  * XXX - The 32-bit compatibility layer for Linux on IA-64
 353                  * is slightly broken. It correctly converts the structures
 354                  * to and from kernel land from 64 bit to 32 bit but
 355                  * doesn't update ifc.ifc_len, leaving it larger than the
 356                  * amount really used. This means we read off the end
 357                  * of the buffer and encounter an interface with an
 358                  * "empty" name. Since this is highly unlikely to ever
 359                  * occur in a valid case we can just finish looking for
 360                  * interfaces if we see an empty name.
 361                  */
 362                 if (!(*ifrp->ifr_name))
 363                         break;
 364
 365                 /*
 366                  * Skip entries that begin with "dummy".
 367                  * XXX - what are these?  Is this Linux-specific?
 368                  * Are there platforms on which we shouldn't do this?
 369                  */
 370                 if (strncmp(ifrp->ifr_name, "dummy", 5) == 0)
 371                         continue;
 372
 373                 /*
 374                  * Get the flags for this interface, and skip it if it's
 375                  * not up.
 376                  */
 377                 strncpy(ifrflags.ifr_name, ifrp->ifr_name,
 378                     sizeof(ifrflags.ifr_name));
 379                 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) {
 380                         if (errno == ENXIO)
 381                                 continue;
 382                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 383                             "SIOCGIFFLAGS: %.*s: %s",
 384                             (int)sizeof(ifrflags.ifr_name),
 385                             ifrflags.ifr_name,
 386                             pcap_strerror(errno));
 387                         ret = -1;
 388                         break;
 389                 }
 390                 if (!(ifrflags.ifr_flags & IFF_UP))
 391                         continue;
 392
 393                 /*
 394                  * Get the netmask for this address on this interface.
 395                  */
 396                 strncpy(ifrnetmask.ifr_name, ifrp->ifr_name,
 397                     sizeof(ifrnetmask.ifr_name));
 398                 memcpy(&ifrnetmask.ifr_addr, &ifrp->ifr_addr,
 399                     sizeof(ifrnetmask.ifr_addr));
 400                 if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifrnetmask) < 0) {
 401                         if (errno == EADDRNOTAVAIL) {
 402                                 /*
 403                                  * Not available.
 404                                  */
 405                                 netmask = NULL;
 406                                 netmask_size = 0;
 407                         } else {
 408                                 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 409                                     "SIOCGIFNETMASK: %.*s: %s",
 410                                     (int)sizeof(ifrnetmask.ifr_name),
 411                                     ifrnetmask.ifr_name,
 412                                     pcap_strerror(errno));
 413                                 ret = -1;
 414                                 break;
 415                         }
 416                 } else {
 417                         netmask = &ifrnetmask.ifr_addr;
 418                         netmask_size = SA_LEN(netmask);
 419                 }
 420
 421                 /*
 422                  * Get the broadcast address for this address on this
 423                  * interface (if any).
 424                  */
 425                 if (ifrflags.ifr_flags & IFF_BROADCAST) {
 426                         strncpy(ifrbroadaddr.ifr_name, ifrp->ifr_name,
 427                             sizeof(ifrbroadaddr.ifr_name));
 428                         memcpy(&ifrbroadaddr.ifr_addr, &ifrp->ifr_addr,
 429                             sizeof(ifrbroadaddr.ifr_addr));
 430                         if (ioctl(fd, SIOCGIFBRDADDR,
 431                             (char *)&ifrbroadaddr) < 0) {
 432                                 if (errno == EADDRNOTAVAIL) {
 433                                         /*
 434                                          * Not available.
 435                                          */
 436                                         broadaddr = NULL;
 437                                         broadaddr_size = 0;
 438                                 } else {
 439                                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 440                                             "SIOCGIFBRDADDR: %.*s: %s",
 441                                             (int)sizeof(ifrbroadaddr.ifr_name),
 442                                             ifrbroadaddr.ifr_name,
 443                                             pcap_strerror(errno));
 444                                         ret = -1;
 445                                         break;
 446                                 }
 447                         } else {
 448                                 broadaddr = &ifrbroadaddr.ifr_broadaddr;
 449                                 broadaddr_size = SA_LEN(broadaddr);
 450                         }
 451                 } else {
 452                         /*
 453                          * Not a broadcast interface, so no broadcast
 454                          * address.
 455                          */
 456                         broadaddr = NULL;
 457                         broadaddr_size = 0;
 458                 }
 459
 460                 /*
 461                  * Get the destination address for this address on this
 462                  * interface (if any).
 463                  */
 464                 if (ifrflags.ifr_flags & IFF_POINTOPOINT) {
 465                         strncpy(ifrdstaddr.ifr_name, ifrp->ifr_name,
 466                             sizeof(ifrdstaddr.ifr_name));
 467                         memcpy(&ifrdstaddr.ifr_addr, &ifrp->ifr_addr,
 468                             sizeof(ifrdstaddr.ifr_addr));
 469                         if (ioctl(fd, SIOCGIFDSTADDR,
 470                             (char *)&ifrdstaddr) < 0) {
 471                                 if (errno == EADDRNOTAVAIL) {
 472                                         /*
 473                                          * Not available.
 474                                          */
 475                                         dstaddr = NULL;
 476                                         dstaddr_size = 0;
 477                                 } else {
 478                                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 479                                             "SIOCGIFDSTADDR: %.*s: %s",
 480                                             (int)sizeof(ifrdstaddr.ifr_name),
 481                                             ifrdstaddr.ifr_name,
 482                                             pcap_strerror(errno));
 483                                         ret = -1;
 484                                         break;
 485                                 }
 486                         } else {
 487                                 dstaddr = &ifrdstaddr.ifr_dstaddr;
 488                                 dstaddr_size = SA_LEN(dstaddr);
 489                         }
 490                 } else {
 491                         /*
 492                          * Not a point-to-point interface, so no destination
 493                          * address.
 494                          */
 495                         dstaddr = NULL;
 496                         dstaddr_size = 0;
 497                 }
 498
 499 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER)
 500                 /*
 501                  * If this entry has a colon followed by a number at
 502                  * the end, it's a logical interface.  Those are just
 503                  * the way you assign multiple IP addresses to a real
 504                  * interface, so an entry for a logical interface should
 505                  * be treated like the entry for the real interface;
 506                  * we do that by stripping off the ":" and the number.
 507                  */
 508                 p = strchr(ifrp->ifr_name, ':');
 509                 if (p != NULL) {
 510                         /*
 511                          * We have a ":"; is it followed by a number?
 512                          */
 513                         q = p + 1;
 514                         while (isdigit((unsigned char)*q))
 515                                 q++;
 516                         if (*q == '\0') {
 517                                 /*
 518                                  * All digits after the ":" until the end.
 519                                  * Strip off the ":" and everything after
 520                                  * it.
 521                                  */
 522                                 *p = '\0';
 523                         }
 524                 }
 525 #endif
 526
 527                 /*
 528                  * Add information for this address to the list.
 529                  */
 530                 if (add_addr_to_iflist(&devlist, ifrp->ifr_name,
 531                     ifrflags.ifr_flags, &ifrp->ifr_addr,
 532                     SA_LEN(&ifrp->ifr_addr), netmask, netmask_size,
 533                     broadaddr, broadaddr_size, dstaddr, dstaddr_size,
 534                     errbuf) < 0) {
 535                         ret = -1;
 536                         break;
 537                 }
 538         }
 539         free(buf);
 540
 541 #ifdef HAVE_PROC_NET_DEV
 542         if (ret != -1) {
 543                 /*
 544                  * We haven't had any errors yet; now read "/proc/net/dev",
 545                  * and add to the list of interfaces all interfaces listed
 546                  * there that we don't already have, because, on Linux,
 547                  * SIOCGIFCONF reports only interfaces with IPv4 addresses,
 548                  * so you need to read "/proc/net/dev" to get the names of
 549                  * the rest of the interfaces.
 550                  */
 551                 ret = scan_proc_net_dev(&devlist, fd, errbuf);
 552         }
 553 #endif
 554         (void)close(fd);
 555
 556         if (ret != -1) {
 557                 /*
 558                  * We haven't had any errors yet; do any platform-specific
 559                  * operations to add devices.
 560                  */
 561                 if (pcap_platform_finddevs(&devlist, errbuf) < 0)
 562                         ret = -1;
 563         }
 564
 565         if (ret == -1) {
 566                 /*
 567                  * We had an error; free the list we've been constructing.
 568                  */
 569                 if (devlist != NULL) {
 570                         pcap_freealldevs(devlist);
 571                         devlist = NULL;
 572                 }
 573         }
 574
 575         *alldevsp = devlist;
 576         return (ret);
 577 }