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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  23  */
  24
  25 #ifdef HAVE_CONFIG_H
  26 # include "config.h"
  27 #endif
  28
  29 #include <glib.h>
  30
  31 #ifdef HAVE_LIBPCAP
  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 #include <pcap.h>
  51
  52 /*
  53  * Keep Digital UNIX happy when including <net/if.h>.
  54  */
  55 struct mbuf;
  56 struct rtentry;
  57 #include <net/if.h>
  58
  59 #ifdef HAVE_SYS_SOCKIO_H
  60 # include <sys/sockio.h>
  61 #endif
  62
  63 #include "capture-pcap-util.h"
  64 #include "capture-pcap-util-int.h"
  65
  66 #ifndef HAVE_PCAP_FINDALLDEVS
  67 struct search_user_data {
  68         char    *name;
  69         if_info_t *if_info;
  70 };
  71
  72 static void
  73 search_for_if_cb(gpointer data, gpointer user_data);
  74 #endif
  75
  76 GList *
  77 get_interface_list(int *err, char **err_str)
  78 {
  79 #ifdef HAVE_PCAP_FINDALLDEVS
  80         return get_interface_list_findalldevs(err, err_str);
  81 #else
  82         GList  *il = NULL;
  83         gint    nonloopback_pos = 0;
  84         struct  ifreq *ifr, *last;
  85         struct  ifconf ifc;
  86         struct  ifreq ifrflags;
  87         int     sock = socket(AF_INET, SOCK_DGRAM, 0);
  88         struct search_user_data user_data;
  89         pcap_t *pch;
  90         int len, lastlen;
  91         char *buf;
  92         if_info_t *if_info;
  93         char errbuf[PCAP_ERRBUF_SIZE];
  94
  95         if (sock < 0) {
  96                 *err = CANT_GET_INTERFACE_LIST;
  97                 if (err_str != NULL) {
  98                         *err_str = g_strdup_printf(
  99                             "Can't get list of interfaces: error opening socket: %s",
 100                             strerror(errno));
 101                 }
 102                 return NULL;
 103         }
 104
 105         /*
 106          * This code came from: W. Richard Stevens: "UNIX Network Programming",
 107          * Networking APIs: Sockets and XTI, Vol 1, page 434.
 108          */
 109         lastlen = 0;
 110         len = 100 * sizeof(struct ifreq);
 111         for ( ; ; ) {
 112                 buf = g_malloc(len);
 113                 ifc.ifc_len = len;
 114                 ifc.ifc_buf = buf;
 115                 memset (buf, 0, len);
 116                 if (ioctl(sock, SIOCGIFCONF, &ifc) < 0) {
 117                         if (errno != EINVAL || lastlen != 0) {
 118                                 if (err_str != NULL) {
 119                                         *err_str = g_strdup_printf(
 120                                             "Can't get list of interfaces: SIOCGIFCONF ioctl error: %s",
 121                                             strerror(errno));
 122                                 }
 123                                 goto fail;
 124                         }
 125                 } else {
 126                         if ((unsigned) ifc.ifc_len < sizeof(struct ifreq)) {
 127                                 if (err_str != NULL) {
 128                                         *err_str = g_strdup(
 129                                             "Can't get list of interfaces: SIOCGIFCONF ioctl gave too small return buffer");
 130                                 }
 131                                 goto fail;
 132                         }
 133                         if (ifc.ifc_len == lastlen)
 134                                 break;                  /* success, len has not changed */
 135                         lastlen = ifc.ifc_len;
 136                 }
 137                 len += 10 * sizeof(struct ifreq);       /* increment */
 138                 g_free(buf);
 139         }
 140         ifr = (struct ifreq *) ifc.ifc_req;
 141         last = (struct ifreq *) ((char *) ifr + ifc.ifc_len);
 142         while (ifr < last) {
 143                 /*
 144                  * Skip entries that begin with "dummy", or that include
 145                  * a ":" (the latter are Solaris virtuals).
 146                  */
 147                 if (strncmp(ifr->ifr_name, "dummy", 5) == 0 ||
 148                     strchr(ifr->ifr_name, ':') != NULL)
 149                         goto next;
 150
 151                 /*
 152                  * If we already have this interface name on the list,
 153                  * don't add it, but, if we don't already have an IP
 154                  * address for it, add that address (SIOCGIFCONF returns,
 155                  * at least on BSD-flavored systems, one entry per
 156                  * interface *address*; if an interface has multiple
 157                  * addresses, we get multiple entries for it).
 158                  */
 159                 user_data.name = ifr->ifr_name;
 160                 user_data.if_info = NULL;
 161                 g_list_foreach(il, search_for_if_cb, &user_data);
 162                 if (user_data.if_info != NULL) {
 163                         if_info_add_address(user_data.if_info, &ifr->ifr_addr);
 164                         goto next;
 165                 }
 166
 167                 /*
 168                  * Get the interface flags.
 169                  */
 170                 memset(&ifrflags, 0, sizeof ifrflags);
 171                 strncpy(ifrflags.ifr_name, ifr->ifr_name,
 172                     sizeof ifrflags.ifr_name);
 173                 if (ioctl(sock, SIOCGIFFLAGS, (char *)&ifrflags) < 0) {
 174                         if (errno == ENXIO)
 175                                 goto next;
 176                         if (err_str != NULL) {
 177                                 *err_str = g_strdup_printf(
 178                                     "Can't get list of interfaces: SIOCGIFFLAGS error getting flags for interface %s: %s",
 179                                     ifr->ifr_name, strerror(errno));
 180                         }
 181                         goto fail;
 182                 }
 183
 184                 /*
 185                  * Skip interfaces that aren't up.
 186                  */
 187                 if (!(ifrflags.ifr_flags & IFF_UP))
 188                         goto next;
 189
 190                 /*
 191                  * Skip interfaces that we can't open with "libpcap".
 192                  * Open with the minimum packet size - it appears that the
 193                  * IRIX SIOCSNOOPLEN "ioctl" may fail if the capture length
 194                  * supplied is too large, rather than just truncating it.
 195                  */
 196                 pch = pcap_open_live(ifr->ifr_name, MIN_PACKET_SIZE, 0, 0,
 197                     errbuf);
 198                 if (pch == NULL)
 199                         goto next;
 200                 pcap_close(pch);
 201
 202                 /*
 203                  * If it's a loopback interface, add it at the end of the
 204                  * list, otherwise add it after the last non-loopback
 205                  * interface, so all loopback interfaces go at the end - we
 206                  * don't want a loopback interface to be the default capture
 207                  * device unless there are no non-loopback devices.
 208                  */
 209                 if_info = if_info_new(ifr->ifr_name, NULL);
 210                 if_info_add_address(if_info, &ifr->ifr_addr);
 211                 if ((ifrflags.ifr_flags & IFF_LOOPBACK) ||
 212                     strncmp(ifr->ifr_name, "lo", 2) == 0) {
 213                         if_info->loopback = TRUE;
 214                         il = g_list_append(il, if_info);
 215                 } else {
 216                         if_info->loopback = FALSE;
 217                         il = g_list_insert(il, if_info, nonloopback_pos);
 218                         /*
 219                          * Insert the next non-loopback interface after this
 220                          * one.
 221                          */
 222                         nonloopback_pos++;
 223                 }
 224
 225         next:
 226 #ifdef HAVE_SA_LEN
 227                 ifr = (struct ifreq *) ((char *) ifr +
 228                     (ifr->ifr_addr.sa_len > sizeof(ifr->ifr_addr) ?
 229                         ifr->ifr_addr.sa_len : sizeof(ifr->ifr_addr)) +
 230                     IFNAMSIZ);
 231 #else
 232                 ifr = (struct ifreq *) ((char *) ifr + sizeof(struct ifreq));
 233 #endif
 234         }
 235
 236 #ifdef linux
 237         /*
 238          * OK, maybe we have support for the "any" device, to do a cooked
 239          * capture on all interfaces at once.
 240          * Try opening it and, if that succeeds, add it to the end of
 241          * the list of interfaces.
 242          */
 243         pch = pcap_open_live("any", MIN_PACKET_SIZE, 0, 0, errbuf);
 244         if (pch != NULL) {
 245                 /*
 246                  * It worked; we can use the "any" device.
 247                  */
 248                 if_info = if_info_new("any",
 249                     "Pseudo-device that captures on all interfaces");
 250                 il = g_list_insert(il, if_info, -1);
 251                 pcap_close(pch);
 252         }
 253 #endif
 254
 255         g_free(ifc.ifc_buf);
 256         close(sock);
 257
 258         if (il == NULL) {
 259                 /*
 260                  * No interfaces found.
 261                  */
 262                 *err = NO_INTERFACES_FOUND;
 263                 if (err_str != NULL)
 264                         *err_str = NULL;
 265         }
 266         return il;
 267
 268 fail:
 269         if (il != NULL)
 270                 free_interface_list(il);
 271         g_free(ifc.ifc_buf);
 272         close(sock);
 273         *err = CANT_GET_INTERFACE_LIST;
 274         return NULL;
 275 #endif /* HAVE_PCAP_FINDALLDEVS */
 276 }
 277
 278 #ifndef HAVE_PCAP_FINDALLDEVS
 279 static void
 280 search_for_if_cb(gpointer data, gpointer user_data)
 281 {
 282         struct search_user_data *search_user_data = user_data;
 283         if_info_t *if_info = data;
 284
 285         if (strcmp(if_info->name, search_user_data->name) == 0)
 286                 search_user_data->if_info = if_info;
 287 }
 288 #endif /* HAVE_PCAP_FINDALLDEVS */
 289
 290 /*
 291  * Get an error message string for a CANT_GET_INTERFACE_LIST error from
 292  * "get_interface_list()".
 293  */
 294 gchar *
 295 cant_get_if_list_error_message(const char *err_str)
 296 {
 297         return g_strdup_printf("Can't get list of interfaces: %s", err_str);
 298 }
 299
 300 /*
 301  * Append the version of libpcap with which we were compiled to a GString.
 302  */
 303 void
 304 get_compiled_pcap_version(GString *str)
 305 {
 306 #ifdef HAVE_PCAP_VERSION
 307         extern char pcap_version[];
 308
 309         g_string_sprintfa(str, "with libpcap %s", pcap_version);
 310 #else
 311         g_string_append(str, "with libpcap (version unknown)");
 312 #endif
 313 }
 314
 315 /*
 316  * Append the version of libpcap with which we we're running to a GString.
 317  */
 318 void
 319 get_runtime_pcap_version(GString *str)
 320 {
 321         g_string_sprintfa(str, "with ");
 322 #ifdef HAVE_PCAP_LIB_VERSION
 323         g_string_sprintfa(str, pcap_lib_version());
 324 #else
 325         g_string_append(str, "libpcap (version unknown)");
 326 #endif
 327 }
 328
 329 #else /* HAVE_LIBPCAP */
 330
 331 /*
 332  * Append an indication that we were not compiled with libpcap
 333  * to a GString.
 334  */
 335 void
 336 get_compiled_pcap_version(GString *str)
 337 {
 338         g_string_append(str, "without libpcap");
 339 }
 340
 341 /*
 342  * Don't append anything, as we weren't even compiled to use WinPcap.
 343  */
 344 void
 345 get_runtime_pcap_version(GString *str _U_)
 346 {
 347 }
 348
 349 #endif /* HAVE_LIBPCAP */