2d99c2dbb4
svn path=/trunk/; revision=37835
843 lines
32 KiB
C
843 lines
32 KiB
C
/* packet-eth.c
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* Routines for ethernet packet disassembly
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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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, 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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#include <glib.h>
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#include <epan/packet.h>
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#include <epan/prefs.h>
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#include <epan/etypes.h>
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#include <epan/addr_resolv.h>
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#include "packet-eth.h"
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#include "packet-ieee8023.h"
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#include "packet-ipx.h"
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#include "packet-isl.h"
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#include "packet-llc.h"
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#include "packet-sll.h"
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#include "packet-usb.h"
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#include <epan/crc32.h>
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#include <epan/tap.h>
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#include <epan/expert.h>
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/* Assume all packets have an FCS */
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static gboolean eth_assume_fcs = FALSE;
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/* Interpret packets as FW1 monitor file packets if they look as if they are */
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static gboolean eth_interpret_as_fw1_monitor = FALSE;
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/* Preference settings defining conditions for which the CCSDS dissector is called */
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static gboolean ccsds_heuristic_length = FALSE;
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static gboolean ccsds_heuristic_version = FALSE;
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static gboolean ccsds_heuristic_header = FALSE;
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static gboolean ccsds_heuristic_bit = FALSE;
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/* Preference moved over from the old vlan dissector */
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static guint q_in_q_ethertype = 0x9100;
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/* protocols and header fields */
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static int proto_eth = -1;
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static int hf_eth_dst = -1;
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static int hf_eth_src = -1;
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static int hf_eth_len = -1;
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static int hf_eth_vlan_tpid = -1;
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static int hf_eth_vlan_pri = -1;
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static int hf_eth_vlan_cfi = -1;
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static int hf_eth_vlan_id = -1;
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static int hf_eth_type = -1;
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static int hf_eth_invalid_lentype = -1;
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static int hf_eth_addr = -1;
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static int hf_eth_lg = -1;
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static int hf_eth_ig = -1;
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static int hf_eth_trailer = -1;
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static gint ett_ieee8023 = -1;
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static gint ett_ether2 = -1;
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static gint ett_ether = -1;
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static gint ett_addr = -1;
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static gint ett_tag = -1;
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static dissector_handle_t fw1_handle;
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static dissector_handle_t data_handle;
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static heur_dissector_list_t heur_subdissector_list;
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static heur_dissector_list_t eth_trailer_subdissector_list;
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static int eth_tap = -1;
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/* From Table G-2 of IEEE standard 802.1D-2004 */
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static const value_string pri_vals[] = {
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{ 1, "Background" },
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{ 2, "Spare" },
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{ 0, "Best Effort (default)" },
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{ 3, "Excellent Effort" },
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{ 4, "Controlled Load" },
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{ 5, "Video, < 100ms latency and jitter" },
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{ 6, "Voice, < 10ms latency and jitter" },
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{ 7, "Network Control" },
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{ 0, NULL }
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};
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static const value_string cfi_vals[] = {
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{ 0, "Canonical" },
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{ 1, "Non-canonical" },
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{ 0, NULL }
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};
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#define ETH_HEADER_SIZE 14
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static const true_false_string ig_tfs = {
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"Group address (multicast/broadcast)",
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"Individual address (unicast)"
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};
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static const true_false_string lg_tfs = {
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"Locally administered address (this is NOT the factory default)",
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"Globally unique address (factory default)"
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};
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/* These are the Netware-ish names for the different Ethernet frame types.
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EthernetII: The ethernet with a Type field instead of a length field
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Ethernet802.2: An 802.3 header followed by an 802.2 header
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Ethernet802.3: A raw 802.3 packet. IPX/SPX can be the only payload.
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There's no 802.2 hdr in this.
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EthernetSNAP: Basically 802.2, just with 802.2SNAP. For our purposes,
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there's no difference between 802.2 and 802.2SNAP, since we just
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pass it down to the LLC dissector. -- Gilbert
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*/
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#define ETHERNET_II 0
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#define ETHERNET_802_2 1
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#define ETHERNET_802_3 2
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#define ETHERNET_SNAP 3
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void
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capture_eth(const guchar *pd, int offset, int len, packet_counts *ld)
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{
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guint16 etype, length;
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int ethhdr_type; /* the type of ethernet frame */
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if (!BYTES_ARE_IN_FRAME(offset, len, ETH_HEADER_SIZE)) {
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ld->other++;
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return;
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}
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etype = pntohs(&pd[offset+12]);
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if (etype <= IEEE_802_3_MAX_LEN) {
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/* Oh, yuck. Cisco ISL frames require special interpretation of the
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destination address field; fortunately, they can be recognized by
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checking the first 5 octets of the destination address, which are
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01-00-0C-00-00 or 0C-00-0C-00-00 for ISL frames. */
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if ((pd[offset] == 0x01 || pd[offset] == 0x0C) && pd[offset+1] == 0x00
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&& pd[offset+2] == 0x0C && pd[offset+3] == 0x00
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&& pd[offset+4] == 0x00) {
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capture_isl(pd, offset, len, ld);
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return;
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}
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}
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/*
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* If the type/length field is <= the maximum 802.3 length,
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* and is not zero, this is an 802.3 frame, and it's a length
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* field; it might be an Novell "raw 802.3" frame, with no
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* 802.2 LLC header, or it might be a frame with an 802.2 LLC
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* header.
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*
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* If the type/length field is >= the minimum Ethernet II length,
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* this is an Ethernet II frame, and it's a type field.
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*
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* If the type/length field is > maximum 802.3 length and < minimum
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* Ethernet II length, then this is an invalid packet.
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*
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* If the type/length field is zero (ETHERTYPE_UNK), this is
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* a frame used internally by the Cisco MDS switch to contain
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* Fibre Channel ("Vegas"). We treat that as an Ethernet II
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* frame; the dissector for those frames registers itself with
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* an ethernet type of ETHERTYPE_UNK.
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*/
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if (etype > IEEE_802_3_MAX_LEN && etype < ETHERNET_II_MIN_LEN) {
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ld->other++;
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return;
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}
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if (etype <= IEEE_802_3_MAX_LEN && etype != ETHERTYPE_UNK) {
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length = etype;
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/* Is there an 802.2 layer? I can tell by looking at the first 2
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bytes after the 802.3 header. If they are 0xffff, then what
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follows the 802.3 header is an IPX payload, meaning no 802.2.
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(IPX/SPX is they only thing that can be contained inside a
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straight 802.3 packet). A non-0xffff value means that there's an
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802.2 layer inside the 802.3 layer */
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if (pd[offset+14] == 0xff && pd[offset+15] == 0xff) {
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ethhdr_type = ETHERNET_802_3;
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}
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else {
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ethhdr_type = ETHERNET_802_2;
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}
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/* Convert the LLC length from the 802.3 header to a total
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frame length, by adding in the size of any data that preceded
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the Ethernet header, and adding in the Ethernet header size,
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and set the payload and captured-payload lengths to the minima
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of the total length and the frame lengths. */
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length += offset + ETH_HEADER_SIZE;
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if (len > length)
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len = length;
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} else {
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ethhdr_type = ETHERNET_II;
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}
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offset += ETH_HEADER_SIZE;
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switch (ethhdr_type) {
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case ETHERNET_802_3:
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capture_ipx(ld);
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break;
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case ETHERNET_802_2:
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capture_llc(pd, offset, len, ld);
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break;
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case ETHERNET_II:
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capture_ethertype(etype, pd, offset, len, ld);
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break;
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}
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}
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static gboolean check_is_802_2(tvbuff_t *tvb, int fcs_len);
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static void
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dissect_eth_common(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree,
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int fcs_len)
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{
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proto_item *ti = NULL, *tag_item;
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eth_hdr *ehdr;
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gboolean is_802_2;
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proto_tree *fh_tree = NULL;
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const guint8 *src_addr, *dst_addr;
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static eth_hdr ehdrs[4];
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static int ehdr_num=0;
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proto_tree *tree;
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proto_item *addr_item;
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proto_tree *addr_tree=NULL;
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proto_tree *tag_tree;
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gint offset;
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guint8 tag_pri;
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guint16 tag_vlan_id;
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ehdr_num++;
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if(ehdr_num>=4){
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ehdr_num=0;
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}
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ehdr=&ehdrs[ehdr_num];
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tree=parent_tree;
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "Ethernet");
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src_addr=tvb_get_ptr(tvb, 6, 6);
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SET_ADDRESS(&pinfo->dl_src, AT_ETHER, 6, src_addr);
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SET_ADDRESS(&pinfo->src, AT_ETHER, 6, src_addr);
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SET_ADDRESS(&ehdr->src, AT_ETHER, 6, src_addr);
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dst_addr=tvb_get_ptr(tvb, 0, 6);
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SET_ADDRESS(&pinfo->dl_dst, AT_ETHER, 6, dst_addr);
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SET_ADDRESS(&pinfo->dst, AT_ETHER, 6, dst_addr);
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SET_ADDRESS(&ehdr->dst, AT_ETHER, 6, dst_addr);
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ehdr->type = tvb_get_ntohs(tvb, 12);
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tap_queue_packet(eth_tap, pinfo, ehdr);
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/*
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* In case the packet is a non-Ethernet packet inside
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* Ethernet framing, allow heuristic dissectors to take
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* a first look before we assume that it's actually an
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* Ethernet packet.
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*/
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if (dissector_try_heuristic(heur_subdissector_list, tvb, pinfo, parent_tree))
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return;
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if (ehdr->type <= IEEE_802_3_MAX_LEN) {
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/* Oh, yuck. Cisco ISL frames require special interpretation of the
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destination address field; fortunately, they can be recognized by
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checking the first 5 octets of the destination address, which are
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01-00-0C-00-00 for ISL frames. */
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if ((tvb_get_guint8(tvb, 0) == 0x01 ||
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tvb_get_guint8(tvb, 0) == 0x0C) &&
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tvb_get_guint8(tvb, 1) == 0x00 &&
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tvb_get_guint8(tvb, 2) == 0x0C &&
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tvb_get_guint8(tvb, 3) == 0x00 &&
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tvb_get_guint8(tvb, 4) == 0x00) {
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dissect_isl(tvb, pinfo, parent_tree, fcs_len);
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return;
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}
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}
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/*
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* If the type/length field is <= the maximum 802.3 length,
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* and is not zero, this is an 802.3 frame, and it's a length
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* field; it might be an Novell "raw 802.3" frame, with no
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* 802.2 LLC header, or it might be a frame with an 802.2 LLC
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* header.
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*
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* If the type/length field is >= the minimum Ethernet II length,
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* this is an Ethernet II frame, and it's a type field.
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*
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* If the type/length field is > maximum 802.3 length and < minimum
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* Ethernet II length, then this is an invalid packet.
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*
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* If the type/length field is zero (ETHERTYPE_UNK), this is
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* a frame used internally by the Cisco MDS switch to contain
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* Fibre Channel ("Vegas"). We treat that as an Ethernet II
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* frame; the dissector for those frames registers itself with
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* an ethernet type of ETHERTYPE_UNK.
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*/
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if (ehdr->type > IEEE_802_3_MAX_LEN && ehdr->type < ETHERNET_II_MIN_LEN) {
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tvbuff_t *next_tvb;
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col_add_fstr(pinfo->cinfo, COL_INFO,
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"Ethernet Unknown: Invalid length/type: 0x%04x (%d)",
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ehdr->type, ehdr->type);
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ti = proto_tree_add_protocol_format(tree, proto_eth, tvb, 0, ETH_HEADER_SIZE,
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"Ethernet Unknown, Src: %s (%s), Dst: %s (%s)",
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get_ether_name(src_addr), ether_to_str(src_addr),
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get_ether_name(dst_addr), ether_to_str(dst_addr));
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fh_tree = proto_item_add_subtree(ti, ett_ether);
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addr_item = proto_tree_add_ether(fh_tree, hf_eth_dst, tvb, 0, 6, dst_addr);
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if (addr_item)
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addr_tree = proto_item_add_subtree(addr_item, ett_addr);
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proto_tree_add_ether(addr_tree, hf_eth_addr, tvb, 0, 6, dst_addr);
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proto_tree_add_item(addr_tree, hf_eth_lg, tvb, 0, 3, FALSE);
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proto_tree_add_item(addr_tree, hf_eth_ig, tvb, 0, 3, FALSE);
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addr_item = proto_tree_add_ether(fh_tree, hf_eth_src, tvb, 6, 6, src_addr);
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if (addr_item)
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addr_tree = proto_item_add_subtree(addr_item, ett_addr);
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proto_tree_add_ether(addr_tree, hf_eth_addr, tvb, 6, 6, src_addr);
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proto_tree_add_item(addr_tree, hf_eth_lg, tvb, 6, 3, FALSE);
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proto_tree_add_item(addr_tree, hf_eth_ig, tvb, 6, 3, FALSE);
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ti = proto_tree_add_item(fh_tree, hf_eth_invalid_lentype, tvb, 12, 2, FALSE);
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expert_add_info_format(pinfo, ti, PI_PROTOCOL, PI_WARN,
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"Invalid length/type: 0x%04x (%d)", ehdr->type, ehdr->type);
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next_tvb = tvb_new_subset_remaining(tvb, 14);
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call_dissector(data_handle, next_tvb, pinfo, parent_tree);
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return;
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}
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if (ehdr->type <= IEEE_802_3_MAX_LEN && ehdr->type != ETHERTYPE_UNK) {
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is_802_2 = check_is_802_2(tvb, fcs_len);
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col_add_fstr(pinfo->cinfo, COL_INFO, "IEEE 802.3 Ethernet %s",
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(is_802_2 ? "" : "Raw "));
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if (tree) {
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ti = proto_tree_add_protocol_format(tree, proto_eth, tvb, 0, ETH_HEADER_SIZE,
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"IEEE 802.3 Ethernet %s", (is_802_2 ? "" : "Raw "));
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fh_tree = proto_item_add_subtree(ti, ett_ieee8023);
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}
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/* if IP is not referenced from any filters we dont need to worry about
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generating any tree items. We must do this after we created the actual
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protocol above so that proto hier stat still works though.
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*/
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if(!proto_field_is_referenced(parent_tree, proto_eth)){
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tree=NULL;
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fh_tree=NULL;
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}
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addr_item=proto_tree_add_ether(fh_tree, hf_eth_dst, tvb, 0, 6, dst_addr);
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if(addr_item){
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addr_tree = proto_item_add_subtree(addr_item, ett_addr);
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}
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proto_tree_add_ether(addr_tree, hf_eth_addr, tvb, 0, 6, dst_addr);
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proto_tree_add_item(addr_tree, hf_eth_lg, tvb, 0, 3, FALSE);
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proto_tree_add_item(addr_tree, hf_eth_ig, tvb, 0, 3, FALSE);
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addr_item=proto_tree_add_ether(fh_tree, hf_eth_src, tvb, 6, 6, src_addr);
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if(addr_item){
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addr_tree = proto_item_add_subtree(addr_item, ett_addr);
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}
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proto_tree_add_ether(addr_tree, hf_eth_addr, tvb, 6, 6, src_addr);
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proto_tree_add_item(addr_tree, hf_eth_lg, tvb, 6, 3, FALSE);
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proto_tree_add_item(addr_tree, hf_eth_ig, tvb, 6, 3, FALSE);
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dissect_802_3(ehdr->type, is_802_2, tvb, ETH_HEADER_SIZE, pinfo,
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parent_tree, fh_tree, hf_eth_len, hf_eth_trailer, fcs_len);
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} else {
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if (eth_interpret_as_fw1_monitor) {
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if ((dst_addr[0] == 'i') || (dst_addr[0] == 'I') ||
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(dst_addr[0] == 'o') || (dst_addr[0] == 'O')) {
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call_dissector(fw1_handle, tvb, pinfo, parent_tree);
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return;
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}
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}
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col_set_str(pinfo->cinfo, COL_INFO, "Ethernet II");
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if(ehdr->type == ETHERTYPE_VLAN || ehdr->type == q_in_q_ethertype)
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col_append_str(pinfo->cinfo, COL_INFO, " (VLAN tagged)");
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if (parent_tree) {
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if (PTREE_DATA(parent_tree)->visible) {
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ti = proto_tree_add_protocol_format(parent_tree, proto_eth, tvb, 0,
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ETH_HEADER_SIZE, "Ethernet II%s, Src: %s (%s), Dst: %s (%s)",
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(ehdr->type == ETHERTYPE_VLAN || ehdr->type == q_in_q_ethertype) ? " (VLAN tagged)" : "",
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get_ether_name(src_addr), ether_to_str(src_addr),
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get_ether_name(dst_addr), ether_to_str(dst_addr));
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}
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else {
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ti = proto_tree_add_item(parent_tree, proto_eth, tvb, 0, ETH_HEADER_SIZE, FALSE);
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}
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fh_tree = proto_item_add_subtree(ti, ett_ether2);
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}
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addr_item=proto_tree_add_ether(fh_tree, hf_eth_dst, tvb, 0, 6, dst_addr);
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if(addr_item){
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addr_tree = proto_item_add_subtree(addr_item, ett_addr);
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}
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proto_tree_add_ether(addr_tree, hf_eth_addr, tvb, 0, 6, dst_addr);
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proto_tree_add_item(addr_tree, hf_eth_lg, tvb, 0, 3, FALSE);
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proto_tree_add_item(addr_tree, hf_eth_ig, tvb, 0, 3, FALSE);
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addr_item=proto_tree_add_ether(fh_tree, hf_eth_src, tvb, 6, 6, src_addr);
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if(addr_item){
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addr_tree = proto_item_add_subtree(addr_item, ett_addr);
|
|
if (tvb_get_guint8(tvb, 6) & 0x01) {
|
|
expert_add_info_format(pinfo, addr_item, PI_PROTOCOL, PI_WARN,
|
|
"Source MAC must not be a group address: IEEE 802.3-2002, Section 3.2.3(b)");
|
|
}
|
|
}
|
|
proto_tree_add_ether(addr_tree, hf_eth_addr, tvb, 6, 6, src_addr);
|
|
proto_tree_add_item(addr_tree, hf_eth_lg, tvb, 6, 3, FALSE);
|
|
proto_tree_add_item(addr_tree, hf_eth_ig, tvb, 6, 3, FALSE);
|
|
|
|
offset = 12;
|
|
while(ehdr->type == ETHERTYPE_VLAN || ehdr->type == q_in_q_ethertype) {
|
|
tag_item = proto_tree_add_text(fh_tree, tvb, offset, 4, "VLAN tag: ");
|
|
tag_tree = proto_item_add_subtree(tag_item, ett_tag);
|
|
|
|
proto_tree_add_item(tag_tree, hf_eth_vlan_tpid, tvb, offset, 2, FALSE);
|
|
offset += 2;
|
|
|
|
proto_tree_add_item(tag_tree, hf_eth_vlan_pri, tvb, offset, 2, FALSE);
|
|
tag_pri = tvb_get_guint8(tvb, offset) >> 5;
|
|
|
|
proto_tree_add_item(tag_tree, hf_eth_vlan_cfi, tvb, offset, 2, FALSE);
|
|
|
|
proto_tree_add_item(tag_tree, hf_eth_vlan_id, tvb, offset, 2, FALSE);
|
|
tag_vlan_id = tvb_get_ntohs(tvb, offset) & 0x0FFF;
|
|
|
|
proto_item_append_text(tag_item, "VLAN=%u, Priority=%s", tag_vlan_id,
|
|
val_to_str(tag_pri, pri_vals, "Unknown"));
|
|
|
|
if(check_col(pinfo->cinfo, COL_8021Q_VLAN_ID))
|
|
col_add_fstr(pinfo->cinfo, COL_8021Q_VLAN_ID, "%u", tag_vlan_id);
|
|
|
|
offset += 2;
|
|
|
|
ehdr->type = tvb_get_ntohs(tvb, offset);
|
|
}
|
|
offset += 2;
|
|
proto_item_set_len(ti, offset);
|
|
|
|
if (ehdr->type <= IEEE_802_3_MAX_LEN) {
|
|
/* Is there an 802.2 layer? I can tell by looking at the first 2
|
|
bytes after the VLAN header. If they are 0xffff, then what
|
|
follows the VLAN header is an IPX payload, meaning no 802.2.
|
|
(IPX/SPX is they only thing that can be contained inside a
|
|
straight 802.3 packet, so presumably the same applies for
|
|
Ethernet VLAN packets). A non-0xffff value means that there's an
|
|
802.2 layer inside the VLAN layer */
|
|
is_802_2 = TRUE;
|
|
|
|
/* Don't throw an exception for this check (even a BoundsError) */
|
|
if (tvb_length_remaining(tvb, offset) >= 2) {
|
|
if (tvb_get_ntohs(tvb, offset) == 0xffff) {
|
|
is_802_2 = FALSE;
|
|
}
|
|
}
|
|
|
|
dissect_802_3(ehdr->type, is_802_2, tvb, offset, pinfo, parent_tree, fh_tree,
|
|
hf_eth_len, hf_eth_trailer, 0);
|
|
} else {
|
|
ethertype(ehdr->type, tvb, offset, pinfo, parent_tree, fh_tree,
|
|
hf_eth_type, hf_eth_trailer, 0);
|
|
}
|
|
}
|
|
}
|
|
|
|
/* -------------- */
|
|
static gboolean check_is_802_2(tvbuff_t *tvb, int fcs_len)
|
|
{
|
|
volatile gboolean is_802_2;
|
|
volatile int length;
|
|
gint captured_length, reported_length;
|
|
|
|
is_802_2 = TRUE;
|
|
|
|
/* Is there an 802.2 layer? I can tell by looking at the first 2
|
|
bytes after the 802.3 header. If they are 0xffff, then what
|
|
follows the 802.3 header is an IPX payload, meaning no 802.2.
|
|
A non-0xffff value means that there's an 802.2 layer or CCSDS
|
|
layer inside the 802.3 layer */
|
|
|
|
TRY {
|
|
if (tvb_get_ntohs(tvb, 14) == 0xffff) {
|
|
is_802_2 = FALSE;
|
|
}
|
|
/* Is this a CCSDS payload instead of an 802.2 (LLC)?
|
|
Check the conditions enabled by the user for CCSDS presence */
|
|
else if (ccsds_heuristic_length || ccsds_heuristic_version ||
|
|
ccsds_heuristic_header || ccsds_heuristic_bit) {
|
|
gboolean CCSDS_len = TRUE;
|
|
gboolean CCSDS_ver = TRUE;
|
|
gboolean CCSDS_head = TRUE;
|
|
gboolean CCSDS_bit = TRUE;
|
|
/* See if the reported payload size matches the
|
|
size contained in the CCSDS header. */
|
|
if (ccsds_heuristic_length) {
|
|
/* The following technique to account for FCS
|
|
is copied from packet-ieee8023.c dissect_802_3() */
|
|
length = tvb_get_ntohs(tvb, 12);
|
|
reported_length = tvb_reported_length_remaining(tvb, ETH_HEADER_SIZE);
|
|
if (fcs_len > 0) {
|
|
if (reported_length >= fcs_len)
|
|
reported_length -= fcs_len;
|
|
}
|
|
/* Make sure the length in the 802.3 header doesn't go past the end of
|
|
the payload. */
|
|
if (length > reported_length) {
|
|
length = reported_length;
|
|
}
|
|
/* Only allow inspection of 'length' number of bytes. */
|
|
captured_length = tvb_length_remaining(tvb, ETH_HEADER_SIZE);
|
|
if (captured_length > length)
|
|
captured_length = length;
|
|
|
|
/* Check if payload is large enough to contain a CCSDS header */
|
|
if (captured_length >= 6) {
|
|
/* Compare length to packet length contained in CCSDS header. */
|
|
if (length != 7 + tvb_get_ntohs(tvb, ETH_HEADER_SIZE + 4))
|
|
CCSDS_len = FALSE;
|
|
}
|
|
}
|
|
/* Check if CCSDS Version number (first 3 bits of payload) is zero */
|
|
if ((ccsds_heuristic_version) && (tvb_get_bits8(tvb, 8*ETH_HEADER_SIZE, 3)!=0))
|
|
CCSDS_ver = FALSE;
|
|
/* Check if Secondary Header Flag (4th bit of payload) is set to one. */
|
|
if ((ccsds_heuristic_header) && (tvb_get_bits8(tvb, 8*ETH_HEADER_SIZE + 4, 1)!=1))
|
|
CCSDS_head = FALSE;
|
|
/* Check if spare bit (1st bit of 7th word of payload) is zero. */
|
|
if ((ccsds_heuristic_bit) && (tvb_get_bits8(tvb, 8*ETH_HEADER_SIZE + 16*6, 1)!=0))
|
|
CCSDS_bit = FALSE;
|
|
/* If all the conditions are true, don't interpret payload as an 802.2 (LLC).
|
|
* Additional check in packet-802.3.c will distinguish between
|
|
* IPX and CCSDS packets*/
|
|
if (CCSDS_len && CCSDS_ver && CCSDS_head && CCSDS_bit)
|
|
is_802_2 = FALSE;
|
|
}
|
|
}
|
|
CATCH2(BoundsError, ReportedBoundsError) {
|
|
; /* do nothing */
|
|
|
|
}
|
|
ENDTRY;
|
|
return is_802_2;
|
|
}
|
|
|
|
|
|
/*
|
|
* Add an Ethernet trailer - which, for some captures, might be the FCS
|
|
* rather than a pad-to-60-bytes trailer.
|
|
*
|
|
* If fcs_len is 0, we assume the frame has no FCS; if it's 4, we assume
|
|
* it has an FCS; if it's anything else (such as -1, which means "maybe
|
|
* it does, maybe it doesn't"), we try to infer whether it has an FCS.
|
|
*/
|
|
void
|
|
add_ethernet_trailer(packet_info *pinfo, proto_tree *tree, proto_tree *fh_tree,
|
|
int trailer_id, tvbuff_t *tvb, tvbuff_t *trailer_tvb, int fcs_len)
|
|
{
|
|
/* If there're some bytes left over, show those bytes as a trailer.
|
|
|
|
However, if the Ethernet frame was claimed to have had 64 or more
|
|
bytes - i.e., it was at least an FCS worth of data longer than
|
|
the minimum payload size - assume the last 4 bytes of the trailer
|
|
are an FCS. */
|
|
if (trailer_tvb && fh_tree) {
|
|
guint trailer_length, trailer_reported_length;
|
|
gboolean has_fcs = FALSE;
|
|
|
|
if (dissector_try_heuristic(eth_trailer_subdissector_list, trailer_tvb,
|
|
pinfo, tree)) {
|
|
return;
|
|
}
|
|
|
|
trailer_length = tvb_length(trailer_tvb);
|
|
trailer_reported_length = tvb_reported_length(trailer_tvb);
|
|
|
|
if (fcs_len != 0) {
|
|
/* If fcs_len is 4, we assume we definitely have an FCS.
|
|
Otherwise, then, if the frame is big enough that, if we
|
|
have a trailer, it probably inclues an FCS, and we have
|
|
enough space in the trailer for the FCS, we assume we
|
|
have an FCS.
|
|
|
|
"Big enough" means 64 bytes or more; any frame that big
|
|
needs no trailer, as there's no need to pad an Ethernet
|
|
packet past 60 bytes.
|
|
|
|
The trailer must be at least 4 bytes long to have enough
|
|
space for an FCS. */
|
|
|
|
if (fcs_len == 4 || (tvb_reported_length(tvb) >= 64 &&
|
|
trailer_reported_length >= 4)) {
|
|
/* Either we know we have an FCS, or we believe we have an FCS. */
|
|
if (trailer_length < trailer_reported_length) {
|
|
/* The packet is claimed to have enough data for a 4-byte FCS,
|
|
but we didn't capture all of the packet.
|
|
Slice off the 4-byte FCS from the reported length, and
|
|
trim the captured length so it's no more than the reported
|
|
length; that will slice off what of the FCS, if any, is
|
|
in the captured packet. */
|
|
trailer_reported_length -= 4;
|
|
if (trailer_length > trailer_reported_length)
|
|
trailer_length = trailer_reported_length;
|
|
has_fcs = TRUE;
|
|
} else {
|
|
/* We captured all of the packet, including what appears to
|
|
be a 4-byte FCS. Slice it off. */
|
|
trailer_length -= 4;
|
|
trailer_reported_length -= 4;
|
|
has_fcs = TRUE;
|
|
}
|
|
}
|
|
}
|
|
if (trailer_length != 0) {
|
|
tvb_ensure_bytes_exist(tvb, 0, trailer_length);
|
|
proto_tree_add_item(fh_tree, trailer_id, trailer_tvb, 0,
|
|
trailer_length, FALSE);
|
|
}
|
|
if (has_fcs) {
|
|
guint32 sent_fcs = tvb_get_ntohl(trailer_tvb, trailer_length);
|
|
guint32 fcs = crc32_802_tvb(tvb, tvb_length(tvb) - 4);
|
|
if (fcs == sent_fcs) {
|
|
proto_tree_add_text(fh_tree, trailer_tvb, trailer_length, 4,
|
|
"Frame check sequence: 0x%08x [correct]", sent_fcs);
|
|
} else {
|
|
proto_tree_add_text(fh_tree, trailer_tvb, trailer_length, 4,
|
|
"Frame check sequence: 0x%08x [incorrect, should be 0x%08x]",
|
|
sent_fcs, fcs);
|
|
}
|
|
trailer_length += 4;
|
|
}
|
|
proto_tree_set_appendix(fh_tree, tvb, tvb_length(tvb) - trailer_length, trailer_length);
|
|
}
|
|
}
|
|
|
|
/* Called for the Ethernet Wiretap encapsulation type; pass the FCS length
|
|
reported to us, or, if the "assume_fcs" preference is set, pass 4. */
|
|
static void
|
|
dissect_eth_maybefcs(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
|
|
{
|
|
dissect_eth_common(tvb, pinfo, tree,
|
|
eth_assume_fcs ? 4 :
|
|
pinfo->pseudo_header->eth.fcs_len);
|
|
}
|
|
|
|
/* Called by other dissectors This one's for encapsulated Ethernet
|
|
packets that don't include an FCS. */
|
|
static void
|
|
dissect_eth_withoutfcs(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
|
|
{
|
|
dissect_eth_common(tvb, pinfo, tree, 0);
|
|
}
|
|
|
|
/* ...and this one's for encapsulated packets that do. */
|
|
static void
|
|
dissect_eth_withfcs(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
|
|
{
|
|
dissect_eth_common(tvb, pinfo, tree, 4);
|
|
}
|
|
|
|
void
|
|
proto_register_eth(void)
|
|
{
|
|
static hf_register_info hf[] = {
|
|
|
|
{ &hf_eth_dst,
|
|
{ "Destination", "eth.dst", FT_ETHER, BASE_NONE, NULL, 0x0,
|
|
"Destination Hardware Address", HFILL }},
|
|
|
|
{ &hf_eth_src,
|
|
{ "Source", "eth.src", FT_ETHER, BASE_NONE, NULL, 0x0,
|
|
"Source Hardware Address", HFILL }},
|
|
|
|
{ &hf_eth_len,
|
|
{ "Length", "eth.len", FT_UINT16, BASE_DEC, NULL, 0x0,
|
|
NULL, HFILL }},
|
|
|
|
/* registered here but handled in packet-ethertype.c */
|
|
{ &hf_eth_type,
|
|
{ "Type", "eth.type", FT_UINT16, BASE_HEX, VALS(etype_vals), 0x0,
|
|
NULL, HFILL }},
|
|
|
|
{ &hf_eth_invalid_lentype,
|
|
{ "Invalid length/type", "eth.invalid_lentype", FT_UINT16, BASE_HEX_DEC,
|
|
NULL, 0x0, NULL, HFILL }},
|
|
|
|
{ &hf_eth_vlan_tpid,
|
|
{ "Identifier", "eth.vlan.tpid", FT_UINT16, BASE_HEX, VALS(etype_vals), 0x0,
|
|
"Tag Protocol Identifier (TPID)", HFILL }},
|
|
|
|
{ &hf_eth_vlan_pri,
|
|
{ "Priority", "eth.vlan.pri", FT_UINT16, BASE_DEC, VALS(pri_vals), 0xE000,
|
|
"Priority Code Point (PCP)", HFILL }},
|
|
|
|
{ &hf_eth_vlan_cfi,
|
|
{ "CFI", "eth.vlan.cfi", FT_UINT16, BASE_DEC, VALS(cfi_vals), 0x1000,
|
|
"Canonical Format Identifier", HFILL }},
|
|
|
|
{ &hf_eth_vlan_id,
|
|
{ "VLAN", "eth.vlan.id", FT_UINT16, BASE_DEC, NULL, 0x0FFF,
|
|
"VLAN Identifier (VID)", HFILL }},
|
|
|
|
{ &hf_eth_addr,
|
|
{ "Address", "eth.addr", FT_ETHER, BASE_NONE, NULL, 0x0,
|
|
"Source or Destination Hardware Address", HFILL }},
|
|
|
|
{ &hf_eth_trailer,
|
|
{ "Trailer", "eth.trailer", FT_BYTES, BASE_NONE, NULL, 0x0,
|
|
"Ethernet Trailer or Checksum", HFILL }},
|
|
|
|
{ &hf_eth_lg,
|
|
{ "LG bit", "eth.lg", FT_BOOLEAN, 24,
|
|
TFS(&lg_tfs), 0x020000,
|
|
"Specifies if this is a locally administered or globally unique (IEEE assigned) address", HFILL }},
|
|
|
|
{ &hf_eth_ig,
|
|
{ "IG bit", "eth.ig", FT_BOOLEAN, 24,
|
|
TFS(&ig_tfs), 0x010000,
|
|
"Specifies if this is an individual (unicast) or group (broadcast/multicast) address", HFILL }}
|
|
};
|
|
static gint *ett[] = {
|
|
&ett_ieee8023,
|
|
&ett_ether2,
|
|
&ett_ether,
|
|
&ett_addr,
|
|
&ett_tag
|
|
};
|
|
module_t *eth_module;
|
|
|
|
proto_eth = proto_register_protocol("Ethernet", "Ethernet", "eth");
|
|
proto_register_field_array(proto_eth, hf, array_length(hf));
|
|
proto_register_subtree_array(ett, array_length(ett));
|
|
|
|
/* subdissector code */
|
|
register_heur_dissector_list("eth", &heur_subdissector_list);
|
|
register_heur_dissector_list("eth.trailer", ð_trailer_subdissector_list);
|
|
|
|
/* Register configuration preferences */
|
|
eth_module = prefs_register_protocol(proto_eth, NULL);
|
|
|
|
prefs_register_bool_preference(eth_module, "assume_fcs",
|
|
"Assume packets have FCS",
|
|
"Some Ethernet adapters and drivers include the FCS at the end of a packet, others do not. "
|
|
"The Ethernet dissector attempts to guess whether a captured packet has an FCS, "
|
|
"but it cannot always guess correctly.",
|
|
ð_assume_fcs);
|
|
|
|
prefs_register_bool_preference(eth_module, "interpret_as_fw1_monitor",
|
|
"Attempt to interpret as FireWall-1 monitor file",
|
|
"Whether packets should be interpreted as coming from CheckPoint FireWall-1 monitor file if they look as if they do",
|
|
ð_interpret_as_fw1_monitor);
|
|
|
|
prefs_register_uint_preference(eth_module, "qinq_ethertype",
|
|
"802.1QinQ Ethertype (in hex)", "The (hexadecimal) Ethertype used to indicate "
|
|
"802.1QinQ VLAN in VLAN tunneling.", 16, &q_in_q_ethertype);
|
|
|
|
/* This preference is copied over from the old vlan dissector by the set_pref()
|
|
* function in epan/prefs.c. We don't have it in this dissector because there could
|
|
* be multiple VLAN tags nested within the Ethernet header, so we wouldn't know which
|
|
* one to show. */
|
|
prefs_register_obsolete_preference(eth_module, "summary_in_tree");
|
|
|
|
prefs_register_static_text_preference(eth_module, "ccsds_heuristic",
|
|
"These are the conditions to match a payload against in order to determine if this\n"
|
|
"is a CCSDS (Consultative Committee for Space Data Systems) packet within\n"
|
|
"an 802.3 packet. A packet is considered as a possible CCSDS packet only if\n"
|
|
"one or more of the conditions are checked.",
|
|
"Describe the conditions that must be true for the CCSDS dissector to be called");
|
|
|
|
prefs_register_bool_preference(eth_module, "ccsds_heuristic_length",
|
|
"CCSDS Length in header matches payload size",
|
|
"Set the condition that must be true for the CCSDS dissector to be called",
|
|
&ccsds_heuristic_length);
|
|
|
|
prefs_register_bool_preference(eth_module, "ccsds_heuristic_version",
|
|
"CCSDS Version # is zero",
|
|
"Set the condition that must be true for the CCSDS dissector to be called",
|
|
&ccsds_heuristic_version);
|
|
|
|
prefs_register_bool_preference(eth_module, "ccsds_heuristic_header",
|
|
"CCSDS Secondary Header Flag is set",
|
|
"Set the condition that must be true for the CCSDS dissector to be called",
|
|
&ccsds_heuristic_header);
|
|
|
|
prefs_register_bool_preference(eth_module, "ccsds_heuristic_bit",
|
|
"CCSDS Spare bit is cleared",
|
|
"Set the condition that must be true for the CCSDS dissector to be called",
|
|
&ccsds_heuristic_bit);
|
|
|
|
register_dissector("eth_withoutfcs", dissect_eth_withoutfcs, proto_eth);
|
|
register_dissector("eth_withfcs", dissect_eth_withfcs, proto_eth);
|
|
register_dissector("eth", dissect_eth_maybefcs, proto_eth);
|
|
eth_tap = register_tap("eth");
|
|
}
|
|
|
|
void
|
|
proto_reg_handoff_eth(void)
|
|
{
|
|
dissector_handle_t eth_maybefcs_handle, eth_withoutfcs_handle;
|
|
|
|
/* Get a handle for the Firewall-1 dissector. */
|
|
fw1_handle = find_dissector("fw1");
|
|
|
|
/* Get a handle for the generic data dissector. */
|
|
data_handle = find_dissector("data");
|
|
|
|
eth_maybefcs_handle = find_dissector("eth");
|
|
dissector_add_uint("wtap_encap", WTAP_ENCAP_ETHERNET, eth_maybefcs_handle);
|
|
|
|
eth_withoutfcs_handle = find_dissector("eth_withoutfcs");
|
|
dissector_add_uint("ethertype", ETHERTYPE_ETHBRIDGE, eth_withoutfcs_handle);
|
|
dissector_add_uint("chdlctype", ETHERTYPE_ETHBRIDGE, eth_withoutfcs_handle);
|
|
dissector_add_uint("gre.proto", ETHERTYPE_ETHBRIDGE, eth_withoutfcs_handle);
|
|
|
|
dissector_add_uint("sll.ltype", LINUX_SLL_P_ETHERNET, eth_withoutfcs_handle);
|
|
dissector_add_uint("usb.bulk", IF_CLASS_CDC_DATA, eth_withoutfcs_handle);
|
|
|
|
/*
|
|
* This is to handle the output for the Cisco CMTS "cable intercept"
|
|
* command - it encapsulates Ethernet frames in UDP packets, but
|
|
* the UDP port is user-defined.
|
|
*/
|
|
dissector_add_handle("udp.port", eth_withoutfcs_handle);
|
|
}
|