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 1.10 2005-04-08 02:15:49 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 #ifdef HAVE_PROC_NET_DEV
 106 /*
 107  * Get from "/proc/net/dev" all interfaces listed there; if they're
 108  * already in the list of interfaces we have, that won't add another
 109  * instance, but if they're not, that'll add them.
 110  *
 111  * We don't bother getting any addresses for them; it appears you can't
 112  * use SIOCGIFADDR on Linux to get IPv6 addresses for interfaces, and,
 113  * although some other types of addresses can be fetched with SIOCGIFADDR,
 114  * we don't bother with them for now.
 115  *
 116  * We also don't fail if we couldn't open "/proc/net/dev"; we just leave
 117  * the list of interfaces as is.
 118  */
 119 static int
 120 scan_proc_net_dev(pcap_if_t **devlistp, int fd, char *errbuf)
 121 {
 122         FILE *proc_net_f;
 123         char linebuf[512];
 124         int linenum;
 125         unsigned char *p;
 126         char name[512]; /* XXX - pick a size */
 127         char *q, *saveq;
 128         struct ifreq ifrflags;
 129         int ret = 0;
 130
 131         proc_net_f = fopen("/proc/net/dev", "r");
 132         if (proc_net_f == NULL)
 133                 return (0);
 134
 135         for (linenum = 1;
 136             fgets(linebuf, sizeof linebuf, proc_net_f) != NULL; linenum++) {
 137                 /*
 138                  * Skip the first two lines - they're headers.
 139                  */
 140                 if (linenum <= 2)
 141                         continue;
 142
 143                 p = &linebuf[0];
 144
 145                 /*
 146                  * Skip leading white space.
 147                  */
 148                 while (*p != '\0' && isspace(*p))
 149                         p++;
 150                 if (*p == '\0' || *p == '\n')
 151                         continue;       /* blank line */
 152
 153                 /*
 154                  * Get the interface name.
 155                  */
 156                 q = &name[0];
 157                 while (*p != '\0' && !isspace(*p)) {
 158                         if (*p == ':') {
 159                                 /*
 160                                  * This could be the separator between a
 161                                  * name and an alias number, or it could be
 162                                  * the separator between a name with no
 163                                  * alias number and the next field.
 164                                  *
 165                                  * If there's a colon after digits, it
 166                                  * separates the name and the alias number,
 167                                  * otherwise it separates the name and the
 168                                  * next field.
 169                                  */
 170                                 saveq = q;
 171                                 while (isdigit(*p))
 172                                         *q++ = *p++;
 173                                 if (*p != ':') {
 174                                         /*
 175                                          * That was the next field,
 176                                          * not the alias number.
 177                                          */
 178                                         q = saveq;
 179                                 }
 180                                 break;
 181                         } else
 182                                 *q++ = *p++;
 183                 }
 184                 *q = '\0';
 185
 186                 /*
 187                  * Get the flags for this interface, and skip it if
 188                  * it's not up.
 189                  */
 190                 strncpy(ifrflags.ifr_name, name, sizeof(ifrflags.ifr_name));
 191                 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) {
 192                         if (errno == ENXIO)
 193                                 continue;
 194                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 195                             "SIOCGIFFLAGS: %.*s: %s",
 196                             (int)sizeof(ifrflags.ifr_name),
 197                             ifrflags.ifr_name,
 198                             pcap_strerror(errno));
 199                         ret = -1;
 200                         break;
 201                 }
 202                 if (!(ifrflags.ifr_flags & IFF_UP))
 203                         continue;
 204
 205                 /*
 206                  * Add an entry for this interface, with no addresses.
 207                  */
 208                 if (pcap_add_if(devlistp, name, ifrflags.ifr_flags, NULL,
 209                     errbuf) == -1) {
 210                         /*
 211                          * Failure.
 212                          */
 213                         ret = -1;
 214                         break;
 215                 }
 216         }
 217         if (ret != -1) {
 218                 /*
 219                  * Well, we didn't fail for any other reason; did we
 220                  * fail due to an error reading the file?
 221                  */
 222                 if (ferror(proc_net_f)) {
 223                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 224                             "Error reading /proc/net/dev: %s",
 225                             pcap_strerror(errno));
 226                         ret = -1;
 227                 }
 228         }
 229
 230         (void)fclose(proc_net_f);
 231         return (ret);
 232 }
 233 #endif /* HAVE_PROC_NET_DEV */
 234
 235 /*
 236  * Get a list of all interfaces that are up and that we can open.
 237  * Returns -1 on error, 0 otherwise.
 238  * The list, as returned through "alldevsp", may be null if no interfaces
 239  * were up and could be opened.
 240  *
 241  * This is the implementation used on platforms that have SIOCGIFCONF but
 242  * don't have any other mechanism for getting a list of interfaces.
 243  *
 244  * XXX - or platforms that have other, better mechanisms but for which
 245  * we don't yet have code to use that mechanism; I think there's a better
 246  * way on Linux, for example.
 247  */
 248 int
 249 pcap_findalldevs(pcap_if_t **alldevsp, char *errbuf)
 250 {
 251         pcap_if_t *devlist = NULL;
 252         register int fd;
 253         register struct ifreq *ifrp, *ifend, *ifnext;
 254         int n;
 255         struct ifconf ifc;
 256         char *buf = NULL;
 257         unsigned buf_size;
 258 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER)
 259         char *p, *q;
 260 #endif
 261         struct ifreq ifrflags, ifrnetmask, ifrbroadaddr, ifrdstaddr;
 262         struct sockaddr *netmask, *broadaddr, *dstaddr;
 263         size_t netmask_size, broadaddr_size, dstaddr_size;
 264         int ret = 0;
 265
 266         /*
 267          * Create a socket from which to fetch the list of interfaces.
 268          */
 269         fd = socket(AF_INET, SOCK_DGRAM, 0);
 270         if (fd < 0) {
 271                 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 272                     "socket: %s", pcap_strerror(errno));
 273                 return (-1);
 274         }
 275
 276         /*
 277          * Start with an 8K buffer, and keep growing the buffer until
 278          * we get the entire interface list or fail to get it for some
 279          * reason other than EINVAL (which is presumed here to mean
 280          * "buffer is too small").
 281          */
 282         buf_size = 8192;
 283         for (;;) {
 284                 buf = malloc(buf_size);
 285                 if (buf == NULL) {
 286                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 287                             "malloc: %s", pcap_strerror(errno));
 288                         (void)close(fd);
 289                         return (-1);
 290                 }
 291
 292                 ifc.ifc_len = buf_size;
 293                 ifc.ifc_buf = buf;
 294                 memset(buf, 0, buf_size);
 295                 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0
 296                     && errno != EINVAL) {
 297                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 298                             "SIOCGIFCONF: %s", pcap_strerror(errno));
 299                         (void)close(fd);
 300                         free(buf);
 301                         return (-1);
 302                 }
 303                 if (ifc.ifc_len < buf_size)
 304                         break;
 305                 free(buf);
 306                 buf_size *= 2;
 307         }
 308
 309         ifrp = (struct ifreq *)buf;
 310         ifend = (struct ifreq *)(buf + ifc.ifc_len);
 311
 312         for (; ifrp < ifend; ifrp = ifnext) {
 313                 /*
 314                  * XXX - what if this isn't an IPv4 address?  Can
 315                  * we still get the netmask, etc. with ioctls on
 316                  * an IPv4 socket?
 317                  *
 318                  * The answer is probably platform-dependent, and
 319                  * if the answer is "no" on more than one platform,
 320                  * the way you work around it is probably platform-
 321                  * dependent as well.
 322                  */
 323                 n = SA_LEN(&ifrp->ifr_addr) + sizeof(ifrp->ifr_name);
 324                 if (n < sizeof(*ifrp))
 325                         ifnext = ifrp + 1;
 326                 else
 327                         ifnext = (struct ifreq *)((char *)ifrp + n);
 328
 329                 /*
 330                  * XXX - The 32-bit compatibility layer for Linux on IA-64
 331                  * is slightly broken. It correctly converts the structures
 332                  * to and from kernel land from 64 bit to 32 bit but
 333                  * doesn't update ifc.ifc_len, leaving it larger than the
 334                  * amount really used. This means we read off the end
 335                  * of the buffer and encounter an interface with an
 336                  * "empty" name. Since this is highly unlikely to ever
 337                  * occur in a valid case we can just finish looking for
 338                  * interfaces if we see an empty name.
 339                  */
 340                 if (!(*ifrp->ifr_name))
 341                         break;
 342
 343                 /*
 344                  * Skip entries that begin with "dummy".
 345                  * XXX - what are these?  Is this Linux-specific?
 346                  * Are there platforms on which we shouldn't do this?
 347                  */
 348                 if (strncmp(ifrp->ifr_name, "dummy", 5) == 0)
 349                         continue;
 350
 351                 /*
 352                  * Get the flags for this interface, and skip it if it's
 353                  * not up.
 354                  */
 355                 strncpy(ifrflags.ifr_name, ifrp->ifr_name,
 356                     sizeof(ifrflags.ifr_name));
 357                 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) {
 358                         if (errno == ENXIO)
 359                                 continue;
 360                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 361                             "SIOCGIFFLAGS: %.*s: %s",
 362                             (int)sizeof(ifrflags.ifr_name),
 363                             ifrflags.ifr_name,
 364                             pcap_strerror(errno));
 365                         ret = -1;
 366                         break;
 367                 }
 368                 if (!(ifrflags.ifr_flags & IFF_UP))
 369                         continue;
 370
 371                 /*
 372                  * Get the netmask for this address on this interface.
 373                  */
 374                 strncpy(ifrnetmask.ifr_name, ifrp->ifr_name,
 375                     sizeof(ifrnetmask.ifr_name));
 376                 memcpy(&ifrnetmask.ifr_addr, &ifrp->ifr_addr,
 377                     sizeof(ifrnetmask.ifr_addr));
 378                 if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifrnetmask) < 0) {
 379                         if (errno == EADDRNOTAVAIL) {
 380                                 /*
 381                                  * Not available.
 382                                  */
 383                                 netmask = NULL;
 384                                 netmask_size = 0;
 385                         } else {
 386                                 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 387                                     "SIOCGIFNETMASK: %.*s: %s",
 388                                     (int)sizeof(ifrnetmask.ifr_name),
 389                                     ifrnetmask.ifr_name,
 390                                     pcap_strerror(errno));
 391                                 ret = -1;
 392                                 break;
 393                         }
 394                 } else {
 395                         netmask = &ifrnetmask.ifr_addr;
 396                         netmask_size = SA_LEN(netmask);
 397                 }
 398
 399                 /*
 400                  * Get the broadcast address for this address on this
 401                  * interface (if any).
 402                  */
 403                 if (ifrflags.ifr_flags & IFF_BROADCAST) {
 404                         strncpy(ifrbroadaddr.ifr_name, ifrp->ifr_name,
 405                             sizeof(ifrbroadaddr.ifr_name));
 406                         memcpy(&ifrbroadaddr.ifr_addr, &ifrp->ifr_addr,
 407                             sizeof(ifrbroadaddr.ifr_addr));
 408                         if (ioctl(fd, SIOCGIFBRDADDR,
 409                             (char *)&ifrbroadaddr) < 0) {
 410                                 if (errno == EADDRNOTAVAIL) {
 411                                         /*
 412                                          * Not available.
 413                                          */
 414                                         broadaddr = NULL;
 415                                         broadaddr_size = 0;
 416                                 } else {
 417                                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 418                                             "SIOCGIFBRDADDR: %.*s: %s",
 419                                             (int)sizeof(ifrbroadaddr.ifr_name),
 420                                             ifrbroadaddr.ifr_name,
 421                                             pcap_strerror(errno));
 422                                         ret = -1;
 423                                         break;
 424                                 }
 425                         } else {
 426                                 broadaddr = &ifrbroadaddr.ifr_broadaddr;
 427                                 broadaddr_size = SA_LEN(broadaddr);
 428                         }
 429                 } else {
 430                         /*
 431                          * Not a broadcast interface, so no broadcast
 432                          * address.
 433                          */
 434                         broadaddr = NULL;
 435                         broadaddr_size = 0;
 436                 }
 437
 438                 /*
 439                  * Get the destination address for this address on this
 440                  * interface (if any).
 441                  */
 442                 if (ifrflags.ifr_flags & IFF_POINTOPOINT) {
 443                         strncpy(ifrdstaddr.ifr_name, ifrp->ifr_name,
 444                             sizeof(ifrdstaddr.ifr_name));
 445                         memcpy(&ifrdstaddr.ifr_addr, &ifrp->ifr_addr,
 446                             sizeof(ifrdstaddr.ifr_addr));
 447                         if (ioctl(fd, SIOCGIFDSTADDR,
 448                             (char *)&ifrdstaddr) < 0) {
 449                                 if (errno == EADDRNOTAVAIL) {
 450                                         /*
 451                                          * Not available.
 452                                          */
 453                                         dstaddr = NULL;
 454                                         dstaddr_size = 0;
 455                                 } else {
 456                                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 457                                             "SIOCGIFDSTADDR: %.*s: %s",
 458                                             (int)sizeof(ifrdstaddr.ifr_name),
 459                                             ifrdstaddr.ifr_name,
 460                                             pcap_strerror(errno));
 461                                         ret = -1;
 462                                         break;
 463                                 }
 464                         } else {
 465                                 dstaddr = &ifrdstaddr.ifr_dstaddr;
 466                                 dstaddr_size = SA_LEN(dstaddr);
 467                         }
 468                 } else {
 469                         /*
 470                          * Not a point-to-point interface, so no destination
 471                          * address.
 472                          */
 473                         dstaddr = NULL;
 474                         dstaddr_size = 0;
 475                 }
 476
 477 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER)
 478                 /*
 479                  * If this entry has a colon followed by a number at
 480                  * the end, it's a logical interface.  Those are just
 481                  * the way you assign multiple IP addresses to a real
 482                  * interface, so an entry for a logical interface should
 483                  * be treated like the entry for the real interface;
 484                  * we do that by stripping off the ":" and the number.
 485                  */
 486                 p = strchr(ifrp->ifr_name, ':');
 487                 if (p != NULL) {
 488                         /*
 489                          * We have a ":"; is it followed by a number?
 490                          */
 491                         q = p + 1;
 492                         while (isdigit((unsigned char)*q))
 493                                 q++;
 494                         if (*q == '\0') {
 495                                 /*
 496                                  * All digits after the ":" until the end.
 497                                  * Strip off the ":" and everything after
 498                                  * it.
 499                                  */
 500                                 *p = '\0';
 501                         }
 502                 }
 503 #endif
 504
 505                 /*
 506                  * Add information for this address to the list.
 507                  */
 508                 if (add_addr_to_iflist(&devlist, ifrp->ifr_name,
 509                     ifrflags.ifr_flags, &ifrp->ifr_addr,
 510                     SA_LEN(&ifrp->ifr_addr), netmask, netmask_size,
 511                     broadaddr, broadaddr_size, dstaddr, dstaddr_size,
 512                     errbuf) < 0) {
 513                         ret = -1;
 514                         break;
 515                 }
 516         }
 517         free(buf);
 518
 519 #ifdef HAVE_PROC_NET_DEV
 520         if (ret != -1) {
 521                 /*
 522                  * We haven't had any errors yet; now read "/proc/net/dev",
 523                  * and add to the list of interfaces all interfaces listed
 524                  * there that we don't already have, because, on Linux,
 525                  * SIOCGIFCONF reports only interfaces with IPv4 addresses,
 526                  * so you need to read "/proc/net/dev" to get the names of
 527                  * the rest of the interfaces.
 528                  */
 529                 ret = scan_proc_net_dev(&devlist, fd, errbuf);
 530         }
 531 #endif
 532         (void)close(fd);
 533
 534         if (ret != -1) {
 535                 /*
 536                  * We haven't had any errors yet; do any platform-specific
 537                  * operations to add devices.
 538                  */
 539                 if (pcap_platform_finddevs(&devlist, errbuf) < 0)
 540                         ret = -1;
 541         }
 542
 543         if (ret == -1) {
 544                 /*
 545                  * We had an error; free the list we've been constructing.
 546                  */
 547                 if (devlist != NULL) {
 548                         pcap_freealldevs(devlist);
 549                         devlist = NULL;
 550                 }
 551         }
 552
 553         *alldevsp = devlist;
 554         return (ret);
 555 }