/* capture-pcap-util.c
* Utility routines for packet capture
*
* $Id: capture-pcap-util.c 22604 2007-08-23 17:49:47Z gerald $
*
* 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
#ifdef HAVE_LIBPCAP
#include <pcap.h>
#include <glib.h>
#include <stdlib.h>
#include <limits.h>
#include <string.h>
#ifdef HAVE_SYS_TYPES_H
# include <sys/types.h>
#endif
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#include <wtap.h>
#include <libpcap.h>
#include "capture-pcap-util.h"
#include "capture-pcap-util-int.h"
#ifndef _WIN32
#include <netinet/in.h>
#endif
/*
* 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, const char *devname
#ifndef _AIX
_U_
#endif
)
{
int linktype;
#ifdef _AIX
const 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
*
* and the ifType value for a loopback device is 24.
*
* The AIX names for LAN devices begin with:
*
* Ethernet en
* 802.3 et
* Token Ring tr
* FDDI fi
*
* and the AIX names for loopback devices begin with "lo".
*
* (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 Wireshark 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, Wireshark,
* and so on.)
*
* XXX - if we conclude we're using AIX libpcap, should we also
* set a flag to cause us to assume the time stamps are in
* seconds-and-nanoseconds form, and to convert them to
* seconds-and-microseconds form before processing them and
* writing them out?
*/
/*
* Find the last component of the device name, which is the
* interface name.
*/
ifacename = strchr(devname, '/');
if (ifacename == NULL)
ifacename = devname;
/* 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, Wireshark, etc. don't care if
* it's Ethernet or 802.3.)
*/
linktype = 1;
}
} else if (strncmp(ifacename, "tr", 2) == 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", 2) == 0) {
if (linktype == 15) {
/*
* That's the RFC 1573 value for FDDI; map it to
* DLT_FDDI.
*/
linktype = 10;
}
} else if (strncmp(ifacename, "lo", 2) == 0) {
if (linktype == 24) {
/*
* That's the RFC 1573 value for "software loopback"
* devices; map it to DLT_NULL, which is what's used
* for loopback devices on BSD.
*/
linktype = 0;
}
}
#endif
return linktype;
}
if_info_t *
if_info_new(char *name, char *description)
{
if_info_t *if_info;
if_info = g_malloc(sizeof (if_info_t));
if_info->name = g_strdup(name);
if (description == NULL)
if_info->description = NULL;
else
if_info->description = g_strdup(description);
if_info->ip_addr = NULL;
if_info->loopback = FALSE;
return if_info;
}
void
if_info_add_address(if_info_t *if_info, struct sockaddr *addr)
{
if_addr_t *ip_addr;
struct sockaddr_in *ai;
#ifdef INET6
struct sockaddr_in6 *ai6;
#endif
switch (addr->sa_family) {
case AF_INET:
ai = (struct sockaddr_in *)addr;
ip_addr = g_malloc(sizeof(*ip_addr));
ip_addr->type = AT_IPv4;
ip_addr->ip_addr.ip4_addr =
*((guint32 *)&(ai->sin_addr.s_addr));
if_info->ip_addr = g_slist_append(if_info->ip_addr, ip_addr);
break;
#ifdef INET6
case AF_INET6:
ai6 = (struct sockaddr_in6 *)addr;
ip_addr = g_malloc(sizeof(*ip_addr));
ip_addr->type = AT_IPv6;
memcpy((void *)&ip_addr->ip_addr.ip6_addr,
(void *)&ai6->sin6_addr.s6_addr,
sizeof ip_addr->ip_addr.ip6_addr);
if_info->ip_addr = g_slist_append(if_info->ip_addr, ip_addr);
break;
#endif
}
}
#ifdef HAVE_PCAP_FINDALLDEVS
/*
* Get all IP address information, and the loopback flag, for the given
* interface.
*/
static void
if_info_ip(if_info_t *if_info, pcap_if_t *d)
{
pcap_addr_t *a;
/* Loopback flag */
if_info->loopback = (d->flags & PCAP_IF_LOOPBACK) ? TRUE : FALSE;
/* All addresses */
for (a = d->addresses; a != NULL; a = a->next) {
if (a->addr != NULL)
if_info_add_address(if_info, a->addr);
}
}
GList *
get_interface_list_findalldevs(int *err, char **err_str)
{
GList *il = NULL;
pcap_if_t *alldevs, *dev;
if_info_t *if_info;
char errbuf[PCAP_ERRBUF_SIZE];
if (pcap_findalldevs(&alldevs, errbuf) == -1) {
*err = CANT_GET_INTERFACE_LIST;
if (err_str != NULL)
*err_str = cant_get_if_list_error_message(errbuf);
return NULL;
}
if (alldevs == NULL) {
/*
* No interfaces found.
*/
*err = NO_INTERFACES_FOUND;
if (err_str != NULL)
*err_str = NULL;
return NULL;
}
for (dev = alldevs; dev != NULL; dev = dev->next) {
if_info = if_info_new(dev->name, dev->description);
il = g_list_append(il, if_info);
if_info_ip(if_info, dev);
}
pcap_freealldevs(alldevs);
return il;
}
#endif /* HAVE_PCAP_FINDALLDEVS */
static void
free_if_info_addr_cb(gpointer addr, gpointer user_data _U_)
{
g_free(addr);
}
static void
free_if_cb(gpointer data, gpointer user_data _U_)
{
if_info_t *if_info = data;
g_free(if_info->name);
if (if_info->description != NULL)
g_free(if_info->description);
g_slist_foreach(if_info->ip_addr, free_if_info_addr_cb, NULL);
g_slist_free(if_info->ip_addr);
g_free(if_info);
}
void
free_interface_list(GList *if_list)
{
g_list_foreach(if_list, free_if_cb, NULL);
g_list_free(if_list);
}
/*
* Get the data-link types available for a libpcap device.
*/
static data_link_info_t *
create_data_link_info(int dlt)
{
data_link_info_t *data_link_info;
#ifdef HAVE_PCAP_DATALINK_VAL_TO_NAME
const char *typename;
#endif
int wtap_encap;
data_link_info = g_malloc(sizeof (data_link_info_t));
data_link_info->dlt = dlt;
#ifdef HAVE_PCAP_DATALINK_VAL_TO_NAME
typename = pcap_datalink_val_to_name(dlt);
if (typename != NULL)
data_link_info->name = g_strdup(typename);
else
#endif
data_link_info->name = g_strdup_printf("DLT %d", dlt);
wtap_encap = wtap_pcap_encap_to_wtap_encap(dlt);
if (wtap_encap == WTAP_ENCAP_UNKNOWN) {
/*
* We don't support this in Wiretap.
* However, we should, so you can capture on it.
* Put in an entry for it, with no description.
*/
data_link_info->description = NULL;
} else {
/*
* If this is null, that's a bug in
* "wtap_pcap_encap_to_wtap_encap()" - it should always
* return a valid encapsulation type - so we assume it's
* not null.
*/
data_link_info->description =
g_strdup(wtap_encap_string(wtap_encap));
}
return data_link_info;
}
GList *
get_pcap_linktype_list(char *devname, char **err_str)
{
GList *linktype_list = NULL;
pcap_t *pch;
int deflt;
char errbuf[PCAP_ERRBUF_SIZE];
#ifdef HAVE_PCAP_SET_DATALINK
int *linktypes;
int i, nlt;
#endif
data_link_info_t *data_link_info;
pch = pcap_open_live(devname, MIN_PACKET_SIZE, 0, 0, errbuf);
if (pch == NULL) {
if (err_str != NULL)
*err_str = g_strdup(errbuf);
return NULL;
}
deflt = get_pcap_linktype(pch, devname);
#ifdef HAVE_PCAP_LIST_DATALINKS
nlt = pcap_list_datalinks(pch, &linktypes);
if (nlt == 0 || linktypes == NULL) {
pcap_close(pch);
if (err_str != NULL)
*err_str = NULL; /* an empty list doesn't mean an error */
return NULL;
}
for (i = 0; i < nlt; i++) {
data_link_info = create_data_link_info(linktypes[i]);
/*
* XXX - for 802.11, make the most detailed 802.11
* version the default, rather than the one the
* device has as the default?
*/
if (linktypes[i] == deflt)
linktype_list = g_list_prepend(linktype_list,
data_link_info);
else
linktype_list = g_list_append(linktype_list,
data_link_info);
}
free(linktypes);
#else
data_link_info = create_data_link_info(deflt);
linktype_list = g_list_append(linktype_list, data_link_info);
#endif
pcap_close(pch);
return linktype_list;
}
static void
free_linktype_cb(gpointer data, gpointer user_data _U_)
{
data_link_info_t *linktype_info = data;
g_free(linktype_info->name);
if (linktype_info->description != NULL)
g_free(linktype_info->description);
}
void
free_pcap_linktype_list(GList *linktype_list)
{
g_list_foreach(linktype_list, free_linktype_cb, NULL);
g_list_free(linktype_list);
}
/* Set the data link type on a pcap. */
const char *
set_pcap_linktype(pcap_t *pch, char *devname
#ifdef HAVE_PCAP_SET_DATALINK
_U_
#endif
, int dlt)
{
#ifdef HAVE_PCAP_SET_DATALINK
if (pcap_set_datalink(pch, dlt) == 0)
return NULL; /* no error */
return pcap_geterr(pch);
#else
/* Let them set it to the type it is; reject any other request. */
if (get_pcap_linktype(pch, devname) == dlt)
return NULL; /* no error */
return "That DLT isn't one of the DLTs supported by this device";
#endif
}
#ifdef HAVE_PCAP_DATALINK_VAL_TO_NAME
const char *
linktype_val_to_name(int dlt)
{
return pcap_datalink_val_to_name(dlt);
}
#endif
#ifdef HAVE_PCAP_DATALINK_NAME_TO_VAL
int linktype_name_to_val(const char *linktype)
{
return pcap_datalink_name_to_val(linktype);
}
#endif
#endif /* HAVE_LIBPCAP */
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