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