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capture-pcap-util-unix.c

/* capture-pcap-util-unix.c
 * UN*X-specific utility routines for packet capture
 *
 * $Id: capture-pcap-util-unix.c 23750 2007-12-04 11:19:29Z kukosa $
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 1998 Gerald Combs
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <glib.h>

#ifdef HAVE_LIBPCAP

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <errno.h>

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif

#ifdef HAVE_SYS_IOCTL_H
#include <sys/ioctl.h>
#endif

#include <pcap.h>

/*
 * Keep Digital UNIX happy when including <net/if.h>.
 */
struct mbuf;
struct rtentry;
#include <net/if.h>

#ifdef HAVE_SYS_SOCKIO_H
# include <sys/sockio.h>
#endif

#include "capture-pcap-util.h"
#include "capture-pcap-util-int.h"

#ifndef HAVE_PCAP_FINDALLDEVS
struct search_user_data {
      char  *name;
      if_info_t *if_info;
};

static void
search_for_if_cb(gpointer data, gpointer user_data);
#endif

#ifdef HAVE_PCAP_REMOTE
GList *
get_remote_interface_list(const char *hostname, const char *port,
                          int auth_type, const char *username,
                          const char *passwd, int *err, char **err_str)
{
    struct pcap_rmtauth auth;
    char source[PCAP_BUF_SIZE];
    char errbuf[PCAP_ERRBUF_SIZE];

    auth.type = auth_type;
    auth.username = username;
    auth.password = passwd;

    if (pcap_createsrcstr(source, PCAP_SRC_IFREMOTE, hostname, port,
                          NULL, errbuf) == -1) {
        *err = CANT_GET_INTERFACE_LIST;
        if (err_str != NULL)
            *err_str = cant_get_if_list_error_message(errbuf);
        return NULL;
    }
    return get_interface_list_findalldevs_ex(source, &auth, err, err_str);
}
#endif

GList *
get_interface_list(int *err, char **err_str)
{
#ifdef HAVE_PCAP_FINDALLDEVS
#ifdef HAVE_PCAP_REMOTE
    char source[PCAP_BUF_SIZE];
    char errbuf[PCAP_ERRBUF_SIZE];

    if (pcap_createsrcstr(source, PCAP_SRC_IFLOCAL,
                          NULL, NULL, NULL, errbuf) == -1) {
        *err = CANT_GET_INTERFACE_LIST;
        if (err_str != NULL)
            *err_str = cant_get_if_list_error_message(errbuf);
        return NULL;
    }
    return get_interface_list_findalldevs_ex(source, NULL, err, err_str);
#else
      return get_interface_list_findalldevs(err, err_str);
#endif
#else
      GList  *il = NULL;
      gint    nonloopback_pos = 0;
      struct  ifreq *ifr, *last;
      struct  ifconf ifc;
      struct  ifreq ifrflags;
      int     sock = socket(AF_INET, SOCK_DGRAM, 0);
      struct search_user_data user_data;
      pcap_t *pch;
      int len, lastlen;
      char *buf;
      if_info_t *if_info;
      char errbuf[PCAP_ERRBUF_SIZE];

      if (sock < 0) {
            *err = CANT_GET_INTERFACE_LIST;
            if (err_str != NULL) {
                  *err_str = g_strdup_printf(
                      "Can't get list of interfaces: error opening socket: %s",
                      strerror(errno));
            }
            return NULL;
      }

      /*
       * This code came from: W. Richard Stevens: "UNIX Network Programming",
       * Networking APIs: Sockets and XTI, Vol 1, page 434.
       */
      lastlen = 0;
      len = 100 * sizeof(struct ifreq);
      for ( ; ; ) {
            buf = g_malloc(len);
            ifc.ifc_len = len;
            ifc.ifc_buf = buf;
            memset (buf, 0, len);
            if (ioctl(sock, SIOCGIFCONF, &ifc) < 0) {
                  if (errno != EINVAL || lastlen != 0) {
                        if (err_str != NULL) {
                              *err_str = g_strdup_printf(
                                  "Can't get list of interfaces: SIOCGIFCONF ioctl error: %s",
                                  strerror(errno));
                        }
                        goto fail;
                  }
            } else {
                  if ((unsigned) ifc.ifc_len < sizeof(struct ifreq)) {
                        if (err_str != NULL) {
                              *err_str = g_strdup(
                                  "Can't get list of interfaces: SIOCGIFCONF ioctl gave too small return buffer");
                        }
                        goto fail;
                  }
                  if (ifc.ifc_len == lastlen)
                        break;                  /* success, len has not changed */
                  lastlen = ifc.ifc_len;
            }
            len += 10 * sizeof(struct ifreq);   /* increment */
            g_free(buf);
      }
      ifr = (struct ifreq *) ifc.ifc_req;
      last = (struct ifreq *) ((char *) ifr + ifc.ifc_len);
      while (ifr < last) {
            /*
             * Skip entries that begin with "dummy", or that include
             * a ":" (the latter are Solaris virtuals).
             */
            if (strncmp(ifr->ifr_name, "dummy", 5) == 0 ||
                strchr(ifr->ifr_name, ':') != NULL)
                  goto next;

            /*
             * If we already have this interface name on the list,
             * don't add it, but, if we don't already have an IP
             * address for it, add that address (SIOCGIFCONF returns,
             * at least on BSD-flavored systems, one entry per
             * interface *address*; if an interface has multiple
             * addresses, we get multiple entries for it).
             */
            user_data.name = ifr->ifr_name;
            user_data.if_info = NULL;
            g_list_foreach(il, search_for_if_cb, &user_data);
            if (user_data.if_info != NULL) {
                  if_info_add_address(user_data.if_info, &ifr->ifr_addr);
                  goto next;
            }

            /*
             * Get the interface flags.
             */
            memset(&ifrflags, 0, sizeof ifrflags);
            strncpy(ifrflags.ifr_name, ifr->ifr_name,
                sizeof ifrflags.ifr_name);
            if (ioctl(sock, SIOCGIFFLAGS, (char *)&ifrflags) < 0) {
                  if (errno == ENXIO)
                        goto next;
                  if (err_str != NULL) {
                        *err_str = g_strdup_printf(
                            "Can't get list of interfaces: SIOCGIFFLAGS error getting flags for interface %s: %s",
                            ifr->ifr_name, strerror(errno));
                  }
                  goto fail;
            }

            /*
             * Skip interfaces that aren't up.
             */
            if (!(ifrflags.ifr_flags & IFF_UP))
                  goto next;

            /*
             * Skip interfaces that we can't open with "libpcap".
             * Open with the minimum packet size - it appears that the
             * IRIX SIOCSNOOPLEN "ioctl" may fail if the capture length
             * supplied is too large, rather than just truncating it.
             */
            pch = pcap_open_live(ifr->ifr_name, MIN_PACKET_SIZE, 0, 0,
                errbuf);
            if (pch == NULL)
                  goto next;
            pcap_close(pch);

            /*
             * If it's a loopback interface, add it at the end of the
             * list, otherwise add it after the last non-loopback
             * interface, so all loopback interfaces go at the end - we
             * don't want a loopback interface to be the default capture
             * device unless there are no non-loopback devices.
             */
            if_info = if_info_new(ifr->ifr_name, NULL);
            if_info_add_address(if_info, &ifr->ifr_addr);
            if ((ifrflags.ifr_flags & IFF_LOOPBACK) ||
                strncmp(ifr->ifr_name, "lo", 2) == 0) {
                  if_info->loopback = TRUE;
                  il = g_list_append(il, if_info);
            } else {
                  if_info->loopback = FALSE;
                  il = g_list_insert(il, if_info, nonloopback_pos);
                  /*
                   * Insert the next non-loopback interface after this
                   * one.
                   */
                  nonloopback_pos++;
            }

      next:
#ifdef HAVE_SA_LEN
            ifr = (struct ifreq *) ((char *) ifr +
                (ifr->ifr_addr.sa_len > sizeof(ifr->ifr_addr) ?
                  ifr->ifr_addr.sa_len : sizeof(ifr->ifr_addr)) +
                IFNAMSIZ);
#else
            ifr = (struct ifreq *) ((char *) ifr + sizeof(struct ifreq));
#endif
      }

#ifdef linux
      /*
       * OK, maybe we have support for the "any" device, to do a cooked
       * capture on all interfaces at once.
       * Try opening it and, if that succeeds, add it to the end of
       * the list of interfaces.
       */
      pch = pcap_open_live("any", MIN_PACKET_SIZE, 0, 0, errbuf);
      if (pch != NULL) {
            /*
             * It worked; we can use the "any" device.
             */
            if_info = if_info_new("any",
                "Pseudo-device that captures on all interfaces");
            il = g_list_insert(il, if_info, -1);
            pcap_close(pch);
      }
#endif

      g_free(ifc.ifc_buf);
      close(sock);

      if (il == NULL) {
            /*
             * No interfaces found.
             */
            *err = NO_INTERFACES_FOUND;
            if (err_str != NULL)
                  *err_str = NULL;
      }
      return il;

fail:
      if (il != NULL)
            free_interface_list(il);
      g_free(ifc.ifc_buf);
      close(sock);
      *err = CANT_GET_INTERFACE_LIST;
      return NULL;
#endif /* HAVE_PCAP_FINDALLDEVS */
}

#ifndef HAVE_PCAP_FINDALLDEVS
static void
search_for_if_cb(gpointer data, gpointer user_data)
{
      struct search_user_data *search_user_data = user_data;
      if_info_t *if_info = data;

      if (strcmp(if_info->name, search_user_data->name) == 0)
            search_user_data->if_info = if_info;
}
#endif /* HAVE_PCAP_FINDALLDEVS */

/*
 * Get an error message string for a CANT_GET_INTERFACE_LIST error from
 * "get_interface_list()".
 */
gchar *
cant_get_if_list_error_message(const char *err_str)
{
      return g_strdup_printf("Can't get list of interfaces: %s", err_str);
}

/*
 * Append the version of libpcap with which we were compiled to a GString.
 */
void
get_compiled_pcap_version(GString *str)
{
#ifdef HAVE_PCAP_VERSION
      extern char pcap_version[];

      g_string_sprintfa(str, "with libpcap %s", pcap_version);
#else
      g_string_append(str, "with libpcap (version unknown)");
#endif
}

/*
 * Append the version of libpcap with which we we're running to a GString.
 */
void
get_runtime_pcap_version(GString *str)
{
      g_string_sprintfa(str, "with ");
#ifdef HAVE_PCAP_LIB_VERSION
      g_string_sprintfa(str, pcap_lib_version());
#else
      g_string_append(str, "libpcap (version unknown)");
#endif
}

#else /* HAVE_LIBPCAP */

/*
 * Append an indication that we were not compiled with libpcap
 * to a GString.
 */
void
get_compiled_pcap_version(GString *str)
{
      g_string_append(str, "without libpcap");
}

/*
 * Don't append anything, as we weren't even compiled to use WinPcap.
 */
void
get_runtime_pcap_version(GString *str _U_)
{
}

#endif /* HAVE_LIBPCAP */

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