2 * Utility routines for packet capture
6 * Ethereal - Network traffic analyzer
7 * By Gerald Combs <gerald@ethereal.com>
8 * Copyright 1998 Gerald Combs
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.
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.
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.
39 #ifdef HAVE_SYS_TYPES_H
40 # include <sys/types.h>
43 #ifdef HAVE_SYS_SOCKET_H
44 #include <sys/socket.h>
48 #include <wtap-capture.h>
50 #include "pcap-util.h"
51 #include "pcap-util-int.h"
54 #include <netinet/in.h>
59 * Get the data-link type for a libpcap device.
60 * This works around AIX 5.x's non-standard and incompatible-with-the-
61 * rest-of-the-universe libpcap.
64 get_pcap_linktype(pcap_t *pch, char *devname
75 linktype = pcap_datalink(pch);
79 * The libpcap that comes with AIX 5.x uses RFC 1573 ifType values
80 * rather than DLT_ values for link-layer types; the ifType values
81 * for LAN devices are:
88 * and the ifType value for a loopback device is 24.
90 * The AIX names for LAN devices begin with:
97 * and the AIX names for loopback devices begin with "lo".
99 * (The difference between "Ethernet" and "802.3" is presumably
100 * whether packets have an Ethernet header, with a packet type,
101 * or an 802.3 header, with a packet length, followed by an 802.2
102 * header and possibly a SNAP header.)
104 * If the device name matches "linktype" interpreted as an ifType
105 * value, rather than as a DLT_ value, we will assume this is AIX's
106 * non-standard, incompatible libpcap, rather than a standard libpcap,
107 * and will map the link-layer type to the standard DLT_ value for
108 * that link-layer type, as that's what the rest of Ethereal expects.
110 * (This means the capture files won't be readable by a tcpdump
111 * linked with AIX's non-standard libpcap, but so it goes. They
112 * *will* be readable by standard versions of tcpdump, Ethereal,
115 * XXX - if we conclude we're using AIX libpcap, should we also
116 * set a flag to cause us to assume the time stamps are in
117 * seconds-and-nanoseconds form, and to convert them to
118 * seconds-and-microseconds form before processing them and
123 * Find the last component of the device name, which is the
126 ifacename = strchr(devname, '/');
127 if (ifacename == NULL)
130 /* See if it matches any of the LAN device names. */
131 if (strncmp(ifacename, "en", 2) == 0) {
134 * That's the RFC 1573 value for Ethernet; map it
139 } else if (strncmp(ifacename, "et", 2) == 0) {
142 * That's the RFC 1573 value for 802.3; map it to
144 * (libpcap, tcpdump, Ethereal, etc. don't care if
145 * it's Ethernet or 802.3.)
149 } else if (strncmp(ifacename, "tr", 2) == 0) {
152 * That's the RFC 1573 value for 802.5 (Token Ring);
153 * map it to DLT_IEEE802, which is what's used for
158 } else if (strncmp(ifacename, "fi", 2) == 0) {
159 if (linktype == 15) {
161 * That's the RFC 1573 value for FDDI; map it to
166 } else if (strncmp(ifacename, "lo", 2) == 0) {
167 if (linktype == 24) {
169 * That's the RFC 1573 value for "software loopback"
170 * devices; map it to DLT_NULL, which is what's used
171 * for loopback devices on BSD.
182 if_info_new(char *name, char *description)
186 if_info = g_malloc(sizeof (if_info_t));
187 if_info->name = g_strdup(name);
188 if (description == NULL)
189 if_info->description = NULL;
191 if_info->description = g_strdup(description);
192 if_info->ip_addr = NULL;
193 if_info->loopback = FALSE;
198 /* get all ip address information from the given interface */
199 static void if_info_ip(if_info_t *if_info, pcap_if_t *d)
204 /* Loopback interface */
205 if_info->loopback = (d->flags & PCAP_IF_LOOPBACK) ? TRUE : FALSE;
208 for(a=d->addresses;a;a=a->next) {
209 switch(a->addr->sa_family)
214 struct sockaddr_in *ai = ((struct sockaddr_in *)(a->addr));
215 ip_addr = g_malloc(sizeof(*ip_addr));
216 *ip_addr = *((guint32 *)&(ai->sin_addr.s_addr));
217 if_info->ip_addr = g_slist_append(if_info->ip_addr, ip_addr);
227 #ifdef HAVE_PCAP_FINDALLDEVS
229 get_interface_list_findalldevs(int *err, char *err_str)
232 pcap_if_t *alldevs, *dev;
235 if (pcap_findalldevs(&alldevs, err_str) == -1) {
236 *err = CANT_GET_INTERFACE_LIST;
240 if (alldevs == NULL) {
242 * No interfaces found.
244 *err = NO_INTERFACES_FOUND;
248 for (dev = alldevs; dev != NULL; dev = dev->next) {
249 if_info = if_info_new(dev->name, dev->description);
250 il = g_list_append(il, if_info);
251 if_info_ip(if_info, dev);
253 pcap_freealldevs(alldevs);
257 #endif /* HAVE_PCAP_FINDALLDEVS */
260 free_if_info_addr_cb(gpointer addr, gpointer user_data _U_)
266 free_if_cb(gpointer data, gpointer user_data _U_)
268 if_info_t *if_info = data;
270 g_free(if_info->name);
271 if (if_info->description != NULL)
272 g_free(if_info->description);
274 g_slist_foreach(if_info->ip_addr, free_if_info_addr_cb, NULL);
275 g_slist_free(if_info->ip_addr);
279 free_interface_list(GList *if_list)
281 g_list_foreach(if_list, free_if_cb, NULL);
282 g_list_free(if_list);
286 * Get the data-link types available for a libpcap device.
288 static data_link_info_t *
289 create_data_link_info(int dlt)
291 data_link_info_t *data_link_info;
292 #ifdef HAVE_PCAP_DATALINK_VAL_TO_NAME
293 const char *typename;
297 data_link_info = g_malloc(sizeof (data_link_info_t));
298 data_link_info->dlt = dlt;
299 #ifdef HAVE_PCAP_DATALINK_VAL_TO_NAME
300 typename = pcap_datalink_val_to_name(dlt);
301 if (typename != NULL)
302 data_link_info->name = g_strdup(typename);
305 data_link_info->name = g_strdup_printf("DLT %d", dlt);
306 wtap_encap = wtap_pcap_encap_to_wtap_encap(dlt);
307 if (wtap_encap == WTAP_ENCAP_UNKNOWN) {
309 * We don't support this in Wiretap.
310 * However, we should, so you can capture on it.
311 * Put in an entry for it, with no description.
313 data_link_info->description = NULL;
316 * If this is null, that's a bug in
317 * "wtap_pcap_encap_to_wtap_encap()" - it should always
318 * return a valid encapsulation type - so we assume it's
321 data_link_info->description =
322 g_strdup(wtap_encap_string(wtap_encap));
324 return data_link_info;
328 get_pcap_linktype_list(char *devname, char *err_buf)
330 GList *linktype_list = NULL;
333 #ifdef HAVE_PCAP_SET_DATALINK
337 data_link_info_t *data_link_info;
339 pch = pcap_open_live(devname, MIN_PACKET_SIZE, 0, 0, err_buf);
342 err_buf[0] = '\0'; /* an empty list doesn't mean an error */
343 deflt = get_pcap_linktype(pch, devname);
344 #ifdef HAVE_PCAP_LIST_DATALINKS
345 nlt = pcap_list_datalinks(pch, &linktypes);
346 if (nlt == 0 || linktypes == NULL)
348 for (i = 0; i < nlt; i++) {
349 data_link_info = create_data_link_info(linktypes[i]);
352 * XXX - for 802.11, make the most detailed 802.11
353 * version the default, rather than the one the
354 * device has as the default?
356 if (linktypes[i] == deflt)
357 linktype_list = g_list_prepend(linktype_list,
360 linktype_list = g_list_append(linktype_list,
365 data_link_info = create_data_link_info(deflt);
366 linktype_list = g_list_append(linktype_list, data_link_info);
370 return linktype_list;
374 free_linktype_cb(gpointer data, gpointer user_data _U_)
376 data_link_info_t *linktype_info = data;
378 g_free(linktype_info->name);
379 if (linktype_info->description != NULL)
380 g_free(linktype_info->description);
384 free_pcap_linktype_list(GList *linktype_list)
386 g_list_foreach(linktype_list, free_linktype_cb, NULL);
387 g_list_free(linktype_list);
390 /* Set the data link type on a pcap. */
392 set_pcap_linktype(pcap_t *pch, char *devname
393 #ifdef HAVE_PCAP_SET_DATALINK
398 #ifdef HAVE_PCAP_SET_DATALINK
399 if (pcap_set_datalink(pch, dlt) == 0)
400 return NULL; /* no error */
401 return pcap_geterr(pch);
403 /* Let them set it to the type it is; reject any other request. */
404 if (get_pcap_linktype(pch, devname) == dlt)
405 return NULL; /* no error */
406 return "That DLT is not one of the DLTs supported by this device";
410 #endif /* HAVE_LIBPCAP */