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+/* pcap-util.c
+ * Utility routines for packet capture
+ *
+ * $Id: pcap-util.c,v 1.1 2001/11/09 07:44:48 guy Exp $
+ *
+ * Ethereal - Network traffic analyzer
+ * By Gerald Combs <gerald@ethereal.com>
+ * 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
+
+#ifdef HAVE_LIBPCAP
+
+#include <glib.h>
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <errno.h>
+
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+
+#ifdef HAVE_SYS_TYPES_H
+#include <sys/types.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>
+
+#ifndef WIN32
+#include <net/if.h>
+#endif
+
+#ifdef HAVE_SYS_SOCKIO_H
+# include <sys/sockio.h>
+#endif
+
+#include "globals.h"
+
+#ifdef WIN32
+#include "capture-wpcap.h"
+#endif
+
+#include "pcap-util.h"
+
+/*
+ * Get the data-link type for a libpcap device.
+ * This works around AIX 5.x's non-standard and incompatible-with-the-
+ * rest-of-the-universe libpcap.
+ */
+int
+get_pcap_linktype(pcap_t *pch, char *devname)
+{
+ int linktype;
+#ifdef AIX
+ char *ifacename;
+#endif
+
+ linktype = pcap_datalink(pch);
+#ifdef AIX
+
+ /*
+ * The libpcap that comes with AIX 5.x uses RFC 1573 ifType values
+ * rather than DLT_ values for link-layer types; the ifType values
+ * for LAN devices are:
+ *
+ * Ethernet 6
+ * 802.3 7
+ * Token Ring 9
+ * FDDI 15
+ *
+ * The AIX names for LAN devices begin with:
+ *
+ * Ethernet en
+ * 802.3 et
+ * Token Ring tr
+ * FDDI fi
+ *
+ * (The difference between "Ethernet" and "802.3" is presumably
+ * whether packets have an Ethernet header, with a packet type,
+ * or an 802.3 header, with a packet length, followed by an 802.2
+ * header and possibly a SNAP header.)
+ *
+ * If the device name matches "linktype" interpreted as an ifType
+ * value, rather than as a DLT_ value, we will assume this is AIX's
+ * non-standard, incompatible libpcap, rather than a standard libpcap,
+ * and will map the link-layer type to the standard DLT_ value for
+ * that link-layer type, as that's what the rest of Ethereal expects.
+ *
+ * (This means the capture files won't be readable by a tcpdump
+ * linked with AIX's non-standard libpcap, but so it goes. They
+ * *will* be readable by standard versions of tcpdump, Ethereal,
+ * and so on.)
+ */
+
+ /*
+ * Find the last component of the device name, which is the
+ * interface name.
+ */
+ ifacename = strchr(devname, '/');
+ if (ifacename == NULL)
+ ifacename = devnames;
+
+ /* See if it matches any of the LAN device names. */
+ if (strncmp(ifacename, "en", 2) == 0) {
+ if (linktype == 6) {
+ /*
+ * That's the RFC 1573 value for Ethernet; map it
+ * to DLT_EN10MB.
+ */
+ linktype = 1;
+ }
+ } else if (strncmp(ifacename, "et", 2) == 0) {
+ if (linktype == 7) {
+ /*
+ * That's the RFC 1573 value for 802.3; map it to
+ * DLT_EN10MB.
+ * (libpcap, tcpdump, Ethereal, etc. don't care if
+ * it's Ethernet or 802.3.)
+ */
+ linktype = 1;
+ }
+ } else if (strncmp(ifacename, "tr") == 0) {
+ if (linktype == 9) {
+ /*
+ * That's the RFC 1573 value for 802.5 (Token Ring);
+ * map it to DLT_IEEE802, which is what's used for
+ * Token Ring.
+ */
+ linktype = 6;
+ }
+ } else if (strncmp(ifacename, "fi") == 0) {
+ if (linktype == 15) {
+ /*
+ * That's the RFC 1573 value for FDDI; map it to
+ * DLT_FDDI.
+ */
+ linktype = 10;
+ }
+ }
+#endif
+
+ return linktype;
+}
+
+/*
+ * If the ability to capture packets is added to Wiretap, these
+ * routines should be moved to the Wiretap source (with
+ * "get_interface_list()" and "free_interface_list()" renamed to
+ * "wtap_get_interface_list()" and "wtap_free_interface_list()",
+ * and modified to use Wiretap routines to attempt to open the
+ * interface.
+ */
+
+struct search_user_data {
+ char *name;
+ int found;
+};
+
+static void
+search_for_if_cb(gpointer data, gpointer user_data);
+
+static void
+free_if_cb(gpointer data, gpointer user_data);
+
+#ifndef WIN32
+GList *
+get_interface_list(int *err, char *err_str)
+{
+ 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 (sock < 0) {
+ sprintf(err_str, "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) {
+ sprintf(err_str,
+ "SIOCGIFCONF ioctl error getting list of interfaces: %s",
+ strerror(errno));
+ goto fail;
+ }
+ } else {
+ if ((unsigned) ifc.ifc_len < sizeof(struct ifreq)) {
+ sprintf(err_str,
+ "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 addresses 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 (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.found = FALSE;
+ g_list_foreach(il, search_for_if_cb, &user_data);
+ if (user_data.found)
+ 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;
+ sprintf(err_str, "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,
+ err_str);
+ 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 ((ifrflags.ifr_flags & IFF_LOOPBACK) ||
+ strncmp(ifr->ifr_name, "lo", 2) == 0)
+ il = g_list_insert(il, g_strdup(ifr->ifr_name), -1);
+ else {
+ il = g_list_insert(il, g_strdup(ifr->ifr_name),
+ 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 + 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, err_str);
+ if (pch != NULL) {
+ /*
+ * It worked; we can use the "any" device.
+ */
+ il = g_list_insert(il, g_strdup("any"), -1);
+ pcap_close(pch);
+ }
+#endif
+
+ g_free(ifc.ifc_buf);
+ close(sock);
+
+ if (il == NULL) {
+ /*
+ * No interfaces found.
+ */
+ *err = NO_INTERFACES_FOUND;
+ }
+ return il;
+
+fail:
+ if (il != NULL) {
+ g_list_foreach(il, free_if_cb, NULL);
+ g_list_free(il);
+ }
+ g_free(ifc.ifc_buf);
+ close(sock);
+ *err = CANT_GET_INTERFACE_LIST;
+ return NULL;
+}
+
+static void
+search_for_if_cb(gpointer data, gpointer user_data)
+{
+ struct search_user_data *search_user_data = user_data;
+
+ if (strcmp((char *)data, search_user_data->name) == 0)
+ search_user_data->found = TRUE;
+}
+#else
+GList *
+get_interface_list(int *err, char *err_str) {
+ GList *il = NULL;
+ wchar_t *names;
+ char *win95names;
+ char newname[255];
+ int i, j, done;
+
+ names = (wchar_t *)pcap_lookupdev(err_str);
+ i = done = 0;
+
+ if (names) {
+ if (names[0]<256) {
+ /* If names[0] is less than 256 it means the first byte is 0
+ This implies that we are using unicode characters */
+ do
+ {
+ j = 0;
+ while (names[i] != 0)
+ newname[j++] = names[i++];
+ i++;
+ if (names[i] == 0)
+ done = 1;
+ newname[j++] = 0;
+ il = g_list_append(il, g_strdup(newname));
+ } while (!done);
+ }
+ else {
+ /* Otherwise we are in Windows 95/98 and using ascii(8 bit)
+ characters */
+ do
+ {
+ win95names=(char *)names;
+ j = 0;
+ while (win95names[i] != 0)
+ newname[j++] = win95names[i++];
+ i++;
+ if (win95names[i] == 0)
+ done = 1;
+ newname[j++] = 0;
+ il = g_list_append(il, g_strdup(newname));
+ } while (!done);
+ }
+ }
+ return(il);
+}
+#endif
+
+static void
+free_if_cb(gpointer data, gpointer user_data)
+{
+ g_free(data);
+}
+
+void
+free_interface_list(GList *if_list)
+{
+ while (if_list != NULL) {
+ g_free(if_list->data);
+ if_list = g_list_remove_link(if_list, if_list);
+ }
+}
+
+#endif /* HAVE_LIBPCAP */
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