452 lines
10 KiB
C
452 lines
10 KiB
C
/* capture-pcap-util.c
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* Utility routines for packet capture
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*
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* $Id$
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 1998 Gerald Combs
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#ifdef HAVE_LIBPCAP
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#include <pcap.h>
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#include <glib.h>
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#include <stdlib.h>
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#include <limits.h>
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#include <string.h>
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#ifdef HAVE_SYS_TYPES_H
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# include <sys/types.h>
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#endif
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#ifdef HAVE_SYS_SOCKET_H
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#include <sys/socket.h>
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#endif
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#include <wtap.h>
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#include <wtap-capture.h>
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#include "capture-pcap-util.h"
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#include "capture-pcap-util-int.h"
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#ifndef _WIN32
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#include <netinet/in.h>
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#endif
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/*
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* Get the data-link type for a libpcap device.
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* This works around AIX 5.x's non-standard and incompatible-with-the-
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* rest-of-the-universe libpcap.
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*/
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int
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get_pcap_linktype(pcap_t *pch, const char *devname
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#ifndef _AIX
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_U_
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#endif
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)
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{
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int linktype;
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#ifdef _AIX
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const char *ifacename;
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#endif
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linktype = pcap_datalink(pch);
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#ifdef _AIX
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/*
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* The libpcap that comes with AIX 5.x uses RFC 1573 ifType values
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* rather than DLT_ values for link-layer types; the ifType values
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* for LAN devices are:
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*
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* Ethernet 6
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* 802.3 7
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* Token Ring 9
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* FDDI 15
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*
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* and the ifType value for a loopback device is 24.
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*
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* The AIX names for LAN devices begin with:
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*
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* Ethernet en
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* 802.3 et
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* Token Ring tr
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* FDDI fi
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*
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* and the AIX names for loopback devices begin with "lo".
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*
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* (The difference between "Ethernet" and "802.3" is presumably
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* whether packets have an Ethernet header, with a packet type,
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* or an 802.3 header, with a packet length, followed by an 802.2
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* header and possibly a SNAP header.)
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*
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* If the device name matches "linktype" interpreted as an ifType
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* value, rather than as a DLT_ value, we will assume this is AIX's
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* non-standard, incompatible libpcap, rather than a standard libpcap,
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* and will map the link-layer type to the standard DLT_ value for
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* that link-layer type, as that's what the rest of Ethereal expects.
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*
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* (This means the capture files won't be readable by a tcpdump
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* linked with AIX's non-standard libpcap, but so it goes. They
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* *will* be readable by standard versions of tcpdump, Ethereal,
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* and so on.)
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*
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* XXX - if we conclude we're using AIX libpcap, should we also
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* set a flag to cause us to assume the time stamps are in
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* seconds-and-nanoseconds form, and to convert them to
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* seconds-and-microseconds form before processing them and
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* writing them out?
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*/
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/*
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* Find the last component of the device name, which is the
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* interface name.
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*/
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ifacename = strchr(devname, '/');
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if (ifacename == NULL)
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ifacename = devname;
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/* See if it matches any of the LAN device names. */
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if (strncmp(ifacename, "en", 2) == 0) {
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if (linktype == 6) {
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/*
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* That's the RFC 1573 value for Ethernet; map it
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* to DLT_EN10MB.
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*/
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linktype = 1;
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}
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} else if (strncmp(ifacename, "et", 2) == 0) {
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if (linktype == 7) {
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/*
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* That's the RFC 1573 value for 802.3; map it to
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* DLT_EN10MB.
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* (libpcap, tcpdump, Ethereal, etc. don't care if
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* it's Ethernet or 802.3.)
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*/
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linktype = 1;
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}
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} else if (strncmp(ifacename, "tr", 2) == 0) {
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if (linktype == 9) {
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/*
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* That's the RFC 1573 value for 802.5 (Token Ring);
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* map it to DLT_IEEE802, which is what's used for
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* Token Ring.
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*/
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linktype = 6;
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}
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} else if (strncmp(ifacename, "fi", 2) == 0) {
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if (linktype == 15) {
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/*
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* That's the RFC 1573 value for FDDI; map it to
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* DLT_FDDI.
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*/
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linktype = 10;
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}
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} else if (strncmp(ifacename, "lo", 2) == 0) {
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if (linktype == 24) {
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/*
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* That's the RFC 1573 value for "software loopback"
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* devices; map it to DLT_NULL, which is what's used
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* for loopback devices on BSD.
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*/
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linktype = 0;
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}
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}
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#endif
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return linktype;
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}
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if_info_t *
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if_info_new(char *name, char *description)
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{
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if_info_t *if_info;
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if_info = g_malloc(sizeof (if_info_t));
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if_info->name = g_strdup(name);
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if (description == NULL)
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if_info->description = NULL;
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else
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if_info->description = g_strdup(description);
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if_info->ip_addr = NULL;
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if_info->loopback = FALSE;
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return if_info;
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}
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void
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if_info_add_address(if_info_t *if_info, struct sockaddr *addr)
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{
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if_addr_t *ip_addr;
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struct sockaddr_in *ai;
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#ifdef INET6
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struct sockaddr_in6 *ai6;
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#endif
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switch (addr->sa_family) {
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case AF_INET:
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ai = (struct sockaddr_in *)addr;
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ip_addr = g_malloc(sizeof(*ip_addr));
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ip_addr->type = AT_IPv4;
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ip_addr->ip_addr.ip4_addr =
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*((guint32 *)&(ai->sin_addr.s_addr));
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if_info->ip_addr = g_slist_append(if_info->ip_addr, ip_addr);
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break;
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#ifdef INET6
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case AF_INET6:
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ai6 = (struct sockaddr_in6 *)addr;
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ip_addr = g_malloc(sizeof(*ip_addr));
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ip_addr->type = AT_IPv6;
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memcpy((void *)&ip_addr->ip_addr.ip6_addr,
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(void *)&ai6->sin6_addr.s6_addr,
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sizeof ip_addr->ip_addr.ip6_addr);
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if_info->ip_addr = g_slist_append(if_info->ip_addr, ip_addr);
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break;
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#endif
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}
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}
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#ifdef HAVE_PCAP_FINDALLDEVS
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/*
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* Get all IP address information, and the loopback flag, for the given
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* interface.
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*/
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static void
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if_info_ip(if_info_t *if_info, pcap_if_t *d)
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{
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pcap_addr_t *a;
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/* Loopback flag */
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if_info->loopback = (d->flags & PCAP_IF_LOOPBACK) ? TRUE : FALSE;
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/* All addresses */
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for (a = d->addresses; a != NULL; a = a->next) {
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if (a->addr != NULL)
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if_info_add_address(if_info, a->addr);
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}
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}
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GList *
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get_interface_list_findalldevs(int *err, char *err_str)
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{
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GList *il = NULL;
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pcap_if_t *alldevs, *dev;
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if_info_t *if_info;
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if (pcap_findalldevs(&alldevs, err_str) == -1) {
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*err = CANT_GET_INTERFACE_LIST;
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return NULL;
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}
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if (alldevs == NULL) {
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/*
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* No interfaces found.
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*/
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*err = NO_INTERFACES_FOUND;
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return NULL;
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}
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for (dev = alldevs; dev != NULL; dev = dev->next) {
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if_info = if_info_new(dev->name, dev->description);
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il = g_list_append(il, if_info);
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if_info_ip(if_info, dev);
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}
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pcap_freealldevs(alldevs);
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return il;
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}
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#endif /* HAVE_PCAP_FINDALLDEVS */
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static void
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free_if_info_addr_cb(gpointer addr, gpointer user_data _U_)
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{
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g_free(addr);
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}
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static void
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free_if_cb(gpointer data, gpointer user_data _U_)
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{
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if_info_t *if_info = data;
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g_free(if_info->name);
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if (if_info->description != NULL)
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g_free(if_info->description);
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g_slist_foreach(if_info->ip_addr, free_if_info_addr_cb, NULL);
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g_slist_free(if_info->ip_addr);
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}
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void
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free_interface_list(GList *if_list)
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{
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g_list_foreach(if_list, free_if_cb, NULL);
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g_list_free(if_list);
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}
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/*
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* Get the data-link types available for a libpcap device.
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*/
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static data_link_info_t *
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create_data_link_info(int dlt)
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{
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data_link_info_t *data_link_info;
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#ifdef HAVE_PCAP_DATALINK_VAL_TO_NAME
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const char *typename;
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#endif
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int wtap_encap;
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data_link_info = g_malloc(sizeof (data_link_info_t));
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data_link_info->dlt = dlt;
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#ifdef HAVE_PCAP_DATALINK_VAL_TO_NAME
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typename = pcap_datalink_val_to_name(dlt);
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if (typename != NULL)
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data_link_info->name = g_strdup(typename);
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else
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#endif
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data_link_info->name = g_strdup_printf("DLT %d", dlt);
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wtap_encap = wtap_pcap_encap_to_wtap_encap(dlt);
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if (wtap_encap == WTAP_ENCAP_UNKNOWN) {
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/*
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* We don't support this in Wiretap.
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* However, we should, so you can capture on it.
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* Put in an entry for it, with no description.
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*/
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data_link_info->description = NULL;
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} else {
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/*
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* If this is null, that's a bug in
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* "wtap_pcap_encap_to_wtap_encap()" - it should always
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* return a valid encapsulation type - so we assume it's
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* not null.
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*/
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data_link_info->description =
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g_strdup(wtap_encap_string(wtap_encap));
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}
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return data_link_info;
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}
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GList *
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get_pcap_linktype_list(const char *devname, char *err_buf)
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{
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GList *linktype_list = NULL;
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pcap_t *pch;
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int deflt;
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#ifdef HAVE_PCAP_SET_DATALINK
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int *linktypes;
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int i, nlt;
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#endif
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data_link_info_t *data_link_info;
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pch = pcap_open_live(devname, MIN_PACKET_SIZE, 0, 0, err_buf);
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if (pch == NULL)
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return NULL;
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err_buf[0] = '\0'; /* an empty list doesn't mean an error */
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deflt = get_pcap_linktype(pch, devname);
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#ifdef HAVE_PCAP_LIST_DATALINKS
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nlt = pcap_list_datalinks(pch, &linktypes);
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if (nlt == 0 || linktypes == NULL) {
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pcap_close(pch);
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return NULL;
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}
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for (i = 0; i < nlt; i++) {
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data_link_info = create_data_link_info(linktypes[i]);
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/*
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* XXX - for 802.11, make the most detailed 802.11
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* version the default, rather than the one the
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* device has as the default?
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*/
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if (linktypes[i] == deflt)
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linktype_list = g_list_prepend(linktype_list,
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data_link_info);
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else
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linktype_list = g_list_append(linktype_list,
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data_link_info);
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}
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free(linktypes);
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#else
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data_link_info = create_data_link_info(deflt);
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linktype_list = g_list_append(linktype_list, data_link_info);
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#endif
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pcap_close(pch);
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return linktype_list;
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}
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static void
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free_linktype_cb(gpointer data, gpointer user_data _U_)
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{
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data_link_info_t *linktype_info = data;
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g_free(linktype_info->name);
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if (linktype_info->description != NULL)
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g_free(linktype_info->description);
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}
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void
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free_pcap_linktype_list(GList *linktype_list)
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{
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g_list_foreach(linktype_list, free_linktype_cb, NULL);
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g_list_free(linktype_list);
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}
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/* Set the data link type on a pcap. */
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const char *
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set_pcap_linktype(pcap_t *pch, char *devname
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#ifdef HAVE_PCAP_SET_DATALINK
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_U_
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#endif
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, int dlt)
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{
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#ifdef HAVE_PCAP_SET_DATALINK
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if (pcap_set_datalink(pch, dlt) == 0)
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return NULL; /* no error */
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return pcap_geterr(pch);
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#else
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/* Let them set it to the type it is; reject any other request. */
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if (get_pcap_linktype(pch, devname) == dlt)
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return NULL; /* no error */
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return "That DLT isn't one of the DLTs supported by this device";
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#endif
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}
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#ifdef HAVE_PCAP_DATALINK_VAL_TO_NAME
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const char *
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linktype_val_to_name(int dlt)
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{
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return pcap_datalink_val_to_name(dlt);
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}
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#endif
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#ifdef HAVE_PCAP_DATALINK_NAME_TO_VAL
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int linktype_name_to_val(const char *linktype)
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{
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return pcap_datalink_name_to_val(linktype);
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}
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#endif
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#endif /* HAVE_LIBPCAP */
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