capture-pcap-util-unix.c

   1 /* capture-pcap-util-unix.c
   2  * UN*X-specific utility routines for packet capture
   3  *
   4  * $Id$
   5  *
   6  * Wireshark - Network traffic analyzer
   7  * By Gerald Combs <gerald@wireshark.org>
   8  * Copyright 1998 Gerald Combs
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License
  12  * as published by the Free Software Foundation; either version 2
  13  * of the License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  23  */
  24
  25 #include "config.h"
  26
  27 #include <glib.h>
  28
  29 #ifdef HAVE_LIBPCAP
  30
  31 #ifndef HAVE_PCAP_FINDALLDEVS
  32
  33 #include <stdlib.h>
  34 #include <string.h>
  35 #include <stdio.h>
  36 #include <errno.h>
  37
  38 #ifdef HAVE_UNISTD_H
  39 #include <unistd.h>
  40 #endif
  41
  42 #ifdef HAVE_SYS_SOCKET_H
  43 #include <sys/socket.h>
  44 #endif
  45
  46 #ifdef HAVE_SYS_IOCTL_H
  47 #include <sys/ioctl.h>
  48 #endif
  49
  50 /*
  51  * Keep Digital UNIX happy when including <net/if.h>.
  52  */
  53 struct mbuf;
  54 struct rtentry;
  55 #include <net/if.h>
  56
  57 #ifdef HAVE_SYS_SOCKIO_H
  58 # include <sys/sockio.h>
  59 #endif
  60
  61 #include "capture-pcap-util.h"
  62
  63 #else
  64
  65 #include <pcap.h>
  66
  67 #endif  /* HAVE_PCAP_FINDALLDEVS */
  68
  69 #include "capture_ifinfo.h"
  70 #include "capture-pcap-util-int.h"
  71
  72 #ifndef HAVE_PCAP_FINDALLDEVS
  73 struct search_user_data {
  74         char    *name;
  75         if_info_t *if_info;
  76 };
  77
  78 static void
  79 search_for_if_cb(gpointer data, gpointer user_data);
  80 #endif
  81
  82 #ifdef HAVE_PCAP_REMOTE
  83 GList *
  84 get_remote_interface_list(const char *hostname, const char *port,
  85                           int auth_type, const char *username,
  86                           const char *passwd, int *err, char **err_str)
  87 {
  88     struct pcap_rmtauth auth;
  89     char source[PCAP_BUF_SIZE];
  90     char errbuf[PCAP_ERRBUF_SIZE];
  91     GList *result;
  92
  93     if (pcap_createsrcstr(source, PCAP_SRC_IFREMOTE, hostname, port,
  94                           NULL, errbuf) == -1) {
  95         *err = CANT_GET_INTERFACE_LIST;
  96         if (err_str != NULL)
  97             *err_str = cant_get_if_list_error_message(errbuf);
  98         return NULL;
  99     }
 100
 101     auth.type = auth_type;
 102     auth.username = g_strdup(username);
 103     auth.password = g_strdup(passwd);
 104
 105     result = get_interface_list_findalldevs_ex(source, &auth, err, err_str);
 106     g_free(auth.username);
 107     g_free(auth.password);
 108
 109     return result;
 110 }
 111 #endif
 112
 113 GList *
 114 get_interface_list(int *err, char **err_str)
 115 {
 116 #ifdef HAVE_PCAP_FINDALLDEVS
 117         return get_interface_list_findalldevs(err, err_str);
 118 #else
 119         GList  *il = NULL;
 120         gint    nonloopback_pos = 0;
 121         struct  ifreq *ifr, *last;
 122         struct  ifconf ifc;
 123         struct  ifreq ifrflags;
 124         int     sock = socket(AF_INET, SOCK_DGRAM, 0);
 125         struct search_user_data user_data;
 126         pcap_t *pch;
 127         int len, lastlen;
 128         char *buf;
 129         if_info_t *if_info;
 130         char errbuf[PCAP_ERRBUF_SIZE];
 131         gboolean loopback;
 132
 133         if (sock < 0) {
 134                 *err = CANT_GET_INTERFACE_LIST;
 135                 if (err_str != NULL) {
 136                         *err_str = g_strdup_printf(
 137                             "Can't get list of interfaces: error opening socket: %s",
 138                             g_strerror(errno));
 139                 }
 140                 return NULL;
 141         }
 142
 143         /*
 144          * This code came from: W. Richard Stevens: "UNIX Network Programming",
 145          * Networking APIs: Sockets and XTI, Vol 1, page 434.
 146          */
 147         lastlen = 0;
 148         len = 100 * sizeof(struct ifreq);
 149         for ( ; ; ) {
 150                 buf = g_malloc(len);
 151                 ifc.ifc_len = len;
 152                 ifc.ifc_buf = buf;
 153                 memset (buf, 0, len);
 154                 if (ioctl(sock, SIOCGIFCONF, &ifc) < 0) {
 155                         if (errno != EINVAL || lastlen != 0) {
 156                                 if (err_str != NULL) {
 157                                         *err_str = g_strdup_printf(
 158                                             "Can't get list of interfaces: SIOCGIFCONF ioctl error: %s",
 159                                             g_strerror(errno));
 160                                 }
 161                                 goto fail;
 162                         }
 163                 } else {
 164                         if ((unsigned int) ifc.ifc_len < sizeof(struct ifreq)) {
 165                                 if (err_str != NULL) {
 166                                         *err_str = g_strdup(
 167                                             "Can't get list of interfaces: SIOCGIFCONF ioctl gave too small return buffer");
 168                                 }
 169                                 goto fail;
 170                         }
 171                         if (ifc.ifc_len == lastlen)
 172                                 break;                  /* success, len has not changed */
 173                         lastlen = ifc.ifc_len;
 174                 }
 175                 len += 10 * sizeof(struct ifreq);       /* increment */
 176                 g_free(buf);
 177         }
 178         ifr = (struct ifreq *) ifc.ifc_req;
 179         last = (struct ifreq *) ((char *) ifr + ifc.ifc_len);
 180         while (ifr < last) {
 181                 /*
 182                  * Skip entries that begin with "dummy", or that include
 183                  * a ":" (the latter are Solaris virtuals).
 184                  */
 185                 if (strncmp(ifr->ifr_name, "dummy", 5) == 0 ||
 186                     strchr(ifr->ifr_name, ':') != NULL)
 187                         goto next;
 188
 189                 /*
 190                  * If we already have this interface name on the list,
 191                  * don't add it, but, if we don't already have an IP
 192                  * address for it, add that address (SIOCGIFCONF returns,
 193                  * at least on BSD-flavored systems, one entry per
 194                  * interface *address*; if an interface has multiple
 195                  * addresses, we get multiple entries for it).
 196                  */
 197                 user_data.name = ifr->ifr_name;
 198                 user_data.if_info = NULL;
 199                 g_list_foreach(il, search_for_if_cb, &user_data);
 200                 if (user_data.if_info != NULL) {
 201                         if_info_add_address(user_data.if_info, &ifr->ifr_addr);
 202                         goto next;
 203                 }
 204
 205                 /*
 206                  * Get the interface flags.
 207                  */
 208                 memset(&ifrflags, 0, sizeof ifrflags);
 209                 g_strlcpy(ifrflags.ifr_name, ifr->ifr_name,
 210                     sizeof ifrflags.ifr_name);
 211                 if (ioctl(sock, SIOCGIFFLAGS, (char *)&ifrflags) < 0) {
 212                         if (errno == ENXIO)
 213                                 goto next;
 214                         if (err_str != NULL) {
 215                                 *err_str = g_strdup_printf(
 216                                     "Can't get list of interfaces: SIOCGIFFLAGS error getting flags for interface %s: %s",
 217                                     ifr->ifr_name, g_strerror(errno));
 218                         }
 219                         goto fail;
 220                 }
 221
 222                 /*
 223                  * Skip interfaces that aren't up.
 224                  */
 225                 if (!(ifrflags.ifr_flags & IFF_UP))
 226                         goto next;
 227
 228                 /*
 229                  * Skip interfaces that we can't open with "libpcap".
 230                  * Open with the minimum packet size - it appears that the
 231                  * IRIX SIOCSNOOPLEN "ioctl" may fail if the capture length
 232                  * supplied is too large, rather than just truncating it.
 233                  */
 234                 pch = pcap_open_live(ifr->ifr_name, MIN_PACKET_SIZE, 0, 0,
 235                     errbuf);
 236                 if (pch == NULL)
 237                         goto next;
 238                 pcap_close(pch);
 239
 240                 /*
 241                  * If it's a loopback interface, add it at the end of the
 242                  * list, otherwise add it after the last non-loopback
 243                  * interface, so all loopback interfaces go at the end - we
 244                  * don't want a loopback interface to be the default capture
 245                  * device unless there are no non-loopback devices.
 246                  */
 247                 loopback = ((ifrflags.ifr_flags & IFF_LOOPBACK) ||
 248                     strncmp(ifr->ifr_name, "lo", 2) == 0);
 249                 if_info = if_info_new(ifr->ifr_name, NULL, loopback);
 250                 if_info_add_address(if_info, &ifr->ifr_addr);
 251                 if (loopback)
 252                         il = g_list_append(il, if_info);
 253                 else {
 254                         il = g_list_insert(il, if_info, nonloopback_pos);
 255                         /*
 256                          * Insert the next non-loopback interface after this
 257                          * one.
 258                          */
 259                         nonloopback_pos++;
 260                 }
 261
 262         next:
 263 #ifdef HAVE_SA_LEN
 264                 ifr = (struct ifreq *) ((char *) ifr +
 265                     (ifr->ifr_addr.sa_len > sizeof(ifr->ifr_addr) ?
 266                         ifr->ifr_addr.sa_len : sizeof(ifr->ifr_addr)) +
 267                     IFNAMSIZ);
 268 #else
 269                 ifr = (struct ifreq *) ((char *) ifr + sizeof(struct ifreq));
 270 #endif
 271         }
 272
 273 #ifdef linux
 274         /*
 275          * OK, maybe we have support for the "any" device, to do a cooked
 276          * capture on all interfaces at once.
 277          * Try opening it and, if that succeeds, add it to the end of
 278          * the list of interfaces.
 279          */
 280         pch = pcap_open_live("any", MIN_PACKET_SIZE, 0, 0, errbuf);
 281         if (pch != NULL) {
 282                 /*
 283                  * It worked; we can use the "any" device.
 284                  */
 285                 if_info = if_info_new("any",
 286                     "Pseudo-device that captures on all interfaces", FALSE);
 287                 il = g_list_insert(il, if_info, -1);
 288                 pcap_close(pch);
 289         }
 290 #endif
 291
 292         g_free(ifc.ifc_buf);
 293         close(sock);
 294
 295         if (il == NULL) {
 296                 /*
 297                  * No interfaces found.
 298                  */
 299                 *err = NO_INTERFACES_FOUND;
 300                 if (err_str != NULL)
 301                         *err_str = NULL;
 302         }
 303         return il;
 304
 305 fail:
 306         if (il != NULL)
 307                 free_interface_list(il);
 308         g_free(ifc.ifc_buf);
 309         close(sock);
 310         *err = CANT_GET_INTERFACE_LIST;
 311         return NULL;
 312 #endif /* HAVE_PCAP_FINDALLDEVS */
 313 }
 314
 315 #ifndef HAVE_PCAP_FINDALLDEVS
 316 static void
 317 search_for_if_cb(gpointer data, gpointer user_data)
 318 {
 319         struct search_user_data *search_user_data = user_data;
 320         if_info_t *if_info = data;
 321
 322         if (strcmp(if_info->name, search_user_data->name) == 0)
 323                 search_user_data->if_info = if_info;
 324 }
 325 #endif /* HAVE_PCAP_FINDALLDEVS */
 326
 327 /*
 328  * Get an error message string for a CANT_GET_INTERFACE_LIST error from
 329  * "get_interface_list()".
 330  */
 331 gchar *
 332 cant_get_if_list_error_message(const char *err_str)
 333 {
 334         return g_strdup_printf("Can't get list of interfaces: %s", err_str);
 335 }
 336
 337 /*
 338  * Append the version of libpcap with which we were compiled to a GString.
 339  */
 340 void
 341 get_compiled_pcap_version(GString *str)
 342 {
 343         /*
 344          * NOTE: in *some* flavors of UN*X, the data from a shared
 345          * library might be linked into executable images that are
 346          * linked with that shared library, in which case you could
 347          * look at pcap_version[] to get the version with which
 348          * the program was compiled.
 349          *
 350          * In other flavors of UN*X, that doesn't happen, so
 351          * pcap_version[] gives you the version the program is
 352          * running with, not the version it was built with, and,
 353          * in at least some of them, if the length of a data item
 354          * referred to by the executable - such as the pcap_version[]
 355          * string - isn't the same in the version of the library
 356          * with which the program was built and the version with
 357          * which it was run, the run-time linker will complain,
 358          * which is Not Good.
 359          *
 360          * So, for now, we just give up on reporting the version
 361          * of libpcap with which we were compiled.
 362          */
 363         g_string_append(str, "with libpcap");
 364 }
 365
 366 /*
 367  * Append the version of libpcap with which we we're running to a GString.
 368  */
 369 void
 370 get_runtime_pcap_version(GString *str)
 371 {
 372         g_string_append_printf(str, "with ");
 373 #ifdef HAVE_PCAP_LIB_VERSION
 374         g_string_append(str, pcap_lib_version());
 375 #else
 376         g_string_append(str, "libpcap (version unknown)");
 377 #endif
 378 }
 379
 380 #else /* HAVE_LIBPCAP */
 381
 382 /*
 383  * Append an indication that we were not compiled with libpcap
 384  * to a GString.
 385  */
 386 void
 387 get_compiled_pcap_version(GString *str)
 388 {
 389         g_string_append(str, "without libpcap");
 390 }
 391
 392 /*
 393  * Don't append anything, as we weren't even compiled to use WinPcap.
 394  */
 395 void
 396 get_runtime_pcap_version(GString *str _U_)
 397 {
 398 }
 399
 400 #endif /* HAVE_LIBPCAP */