![Guy Harris](/assets/img/avatar_default.png)
length field rather than an Ethernet type field) into a "dissect_802_3()" routine. In that routine, catch exceptions thrown by the IPX or LLC dissector or dissectors under them, so that the trailer information is added to the tree even if an exception is thrown (similar to what "ethertype()" does). svn path=/trunk/; revision=3002
317 lines
9.6 KiB
C
317 lines
9.6 KiB
C
/* packet-eth.c
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* Routines for ethernet packet disassembly
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*
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* $Id: packet-eth.c,v 1.60 2001/02/08 07:08:05 guy Exp $
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*
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* Ethereal - Network traffic analyzer
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* By Gerald Combs <gerald@zing.org>
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* Copyright 1998 Gerald Combs
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*
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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_SYS_TYPES_H
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# include <sys/types.h>
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#endif
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#include <glib.h>
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#include "packet.h"
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#include "etypes.h"
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#include "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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extern const value_string etype_vals[];
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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_type = -1;
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static int hf_eth_addr = -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 dissector_handle_t isl_handle;
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#define ETH_HEADER_SIZE 14
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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 u_char *pd, int offset, 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, 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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/* either ethernet802.3 or ethernet802.2 */
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if (etype <= IEEE_802_3_MAX_LEN) {
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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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/* 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 (pd[offset] == 0x01 && pd[offset+1] == 0x00 && pd[offset+2] == 0x0C
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&& pd[offset+3] == 0x00 && pd[offset+4] == 0x00) {
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capture_isl(pd, offset, ld);
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return;
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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 (pi.len > length)
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pi.len = length;
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if (pi.captured_len > length)
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pi.captured_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(pd, offset, ld);
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break;
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case ETHERNET_802_2:
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capture_llc(pd, offset, ld);
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break;
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case ETHERNET_II:
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capture_ethertype(etype, offset, pd, ld);
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break;
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}
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}
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static void
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dissect_eth(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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int orig_captured_len;
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proto_item *ti;
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guint8 *dst, *src;
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const guint8 *pd;
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guint16 etype;
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volatile gboolean is_802_2;
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int eth_offset;
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volatile guint16 length;
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proto_tree *volatile fh_tree = NULL;
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tvb_compat(tvb, &pd, (int*)ð_offset);
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orig_captured_len = pinfo->captured_len;
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if (check_col(pinfo->fd, COL_PROTOCOL))
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col_set_str(pinfo->fd, COL_PROTOCOL, "Ethernet");
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src = tvb_get_ptr(tvb, 6, 6);
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dst = tvb_get_ptr(tvb, 0, 6);
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SET_ADDRESS(&pinfo->dl_src, AT_ETHER, 6, src);
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SET_ADDRESS(&pinfo->src, AT_ETHER, 6, src);
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SET_ADDRESS(&pinfo->dl_dst, AT_ETHER, 6, dst);
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SET_ADDRESS(&pinfo->dst, AT_ETHER, 6, dst);
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etype = tvb_get_ntohs(tvb, 12);
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/* either ethernet802.3 or ethernet802.2 */
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if (etype <= IEEE_802_3_MAX_LEN) {
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length = etype;
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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, 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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call_dissector(isl_handle, tvb, pinfo, tree);
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return;
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}
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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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is_802_2 = TRUE;
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TRY {
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if (tvb_get_ntohs(tvb, 14) == 0xffff) {
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is_802_2 = FALSE;
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}
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}
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CATCH2(BoundsError, ReportedBoundsError) {
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; /* do nothing */
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}
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ENDTRY;
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if (check_col(pinfo->fd, COL_INFO)) {
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col_add_fstr(pinfo->fd, COL_INFO, "IEEE 802.3 %s",
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(is_802_2 ? "" : "Raw "));
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}
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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 %s", (is_802_2 ? "" : "Raw "));
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fh_tree = proto_item_add_subtree(ti, ett_ieee8023);
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proto_tree_add_ether(fh_tree, hf_eth_dst, tvb, 0, 6, dst);
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proto_tree_add_ether(fh_tree, hf_eth_src, tvb, 6, 6, src);
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/* add items for eth.addr filter */
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proto_tree_add_ether_hidden(fh_tree, hf_eth_addr, tvb, 0, 6, dst);
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proto_tree_add_ether_hidden(fh_tree, hf_eth_addr, tvb, 6, 6, src);
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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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XXX - when all dissectors are tvbuffified we shouldn't have to
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do this any more. */
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length += eth_offset + ETH_HEADER_SIZE;
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if (pinfo->len > length)
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pinfo->len = length;
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if (pinfo->captured_len > length)
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pinfo->captured_len = length;
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dissect_802_3(etype, is_802_2, tvb, ETH_HEADER_SIZE, pinfo, tree, fh_tree,
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hf_eth_len, hf_eth_trailer);
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} else {
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if (check_col(pinfo->fd, COL_INFO))
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col_set_str(pinfo->fd, COL_INFO, "Ethernet II");
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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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"Ethernet II");
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fh_tree = proto_item_add_subtree(ti, ett_ether2);
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proto_tree_add_ether(fh_tree, hf_eth_dst, tvb, 0, 6, dst);
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proto_tree_add_ether(fh_tree, hf_eth_src, tvb, 6, 6, src);
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/* add items for eth.addr filter */
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proto_tree_add_ether_hidden(fh_tree, hf_eth_addr, tvb, 0, 6, dst);
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proto_tree_add_ether_hidden(fh_tree, hf_eth_addr, tvb, 6, 6, src);
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}
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ethertype(etype, tvb, ETH_HEADER_SIZE, pinfo, tree, fh_tree, hf_eth_type,
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hf_eth_trailer);
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}
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}
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void
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proto_register_eth(void)
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{
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static hf_register_info hf[] = {
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{ &hf_eth_dst,
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{ "Destination", "eth.dst", FT_ETHER, BASE_NONE, NULL, 0x0,
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"Destination Hardware Address" }},
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{ &hf_eth_src,
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{ "Source", "eth.src", FT_ETHER, BASE_NONE, NULL, 0x0,
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"Source Hardware Address" }},
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{ &hf_eth_len,
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{ "Length", "eth.len", FT_UINT16, BASE_DEC, NULL, 0x0,
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"" }},
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/* registered here but handled in ethertype.c */
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{ &hf_eth_type,
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{ "Type", "eth.type", FT_UINT16, BASE_HEX, VALS(etype_vals), 0x0,
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"" }},
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{ &hf_eth_addr,
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{ "Source or Destination Address", "eth.addr", FT_ETHER, BASE_NONE, NULL, 0x0,
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"Source or Destination Hardware Address" }},
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{ &hf_eth_trailer,
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{ "Trailer", "eth.trailer", FT_BYTES, BASE_NONE, NULL, 0x0,
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"Ethernet Trailer or Checksum" }},
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};
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static gint *ett[] = {
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&ett_ieee8023,
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&ett_ether2,
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};
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proto_eth = proto_register_protocol("Ethernet", "Ethernet", "eth");
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proto_register_field_array(proto_eth, hf, array_length(hf));
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proto_register_subtree_array(ett, array_length(ett));
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register_dissector("eth", dissect_eth, proto_eth);
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}
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void
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proto_reg_handoff_eth(void)
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{
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/*
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* Get a handle for the ISL dissector.
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*/
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isl_handle = find_dissector("isl");
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dissector_add("wtap_encap", WTAP_ENCAP_ETHERNET, dissect_eth,
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proto_eth);
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}
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