forked from osmocom/wireshark
342 lines
10 KiB
C
342 lines
10 KiB
C
/* packet-isl.c
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* Routines for Cisco ISL Ethernet header disassembly
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*
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* $Id: packet-isl.c,v 1.33 2003/08/08 17:57:44 guy Exp $
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*
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* Ethereal - Network traffic analyzer
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* By Gerald Combs <gerald@ethereal.com>
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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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#include <glib.h>
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#include <epan/packet.h>
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#include "packet-isl.h"
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#include "packet-eth.h"
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#include "packet-tr.h"
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#include "etypes.h"
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/*
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* See
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*
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* http://www.cisco.com/warp/public/473/741_4.html
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*
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* and
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*
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* http://www.cisco.com/univercd/cc/td/doc/product/lan/trsrb/frames.htm
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*
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* for information on ISL.
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*/
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static int proto_isl = -1;
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static int hf_isl_dst = -1;
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static int hf_isl_type = -1;
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static int hf_isl_user_eth = -1;
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static int hf_isl_user = -1;
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static int hf_isl_src = -1;
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static int hf_isl_addr = -1;
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static int hf_isl_len = -1;
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static int hf_isl_hsa = -1;
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static int hf_isl_vlan_id = -1;
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static int hf_isl_bpdu = -1;
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static int hf_isl_index = -1;
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static int hf_isl_crc = -1;
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static int hf_isl_src_vlan_id = -1;
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static int hf_isl_explorer = -1;
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static int hf_isl_dst_route_descriptor = -1;
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static int hf_isl_src_route_descriptor = -1;
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static int hf_isl_fcs_not_incl = -1;
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static int hf_isl_esize = -1;
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static gint ett_isl = -1;
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#define ISL_HEADER_SIZE 26
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#define TYPE_ETHER 0x0
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#define TYPE_TR 0x1
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#define TYPE_FDDI 0x2
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#define TYPE_ATM 0x3
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static dissector_handle_t eth_handle;
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static dissector_handle_t tr_handle;
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static dissector_handle_t data_handle;
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void
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capture_isl(const guchar *pd, int offset, int len, packet_counts *ld)
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{
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guint8 type;
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if (!BYTES_ARE_IN_FRAME(offset, len, ISL_HEADER_SIZE)) {
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ld->other++;
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return;
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}
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type = (pd[offset+5] >> 4)&0x0F;
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switch (type) {
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case TYPE_ETHER:
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offset += 14+12; /* skip the header */
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capture_eth(pd, offset, len, ld);
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break;
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case TYPE_TR:
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offset += 14+17; /* skip the header */
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capture_tr(pd, offset, len, ld);
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break;
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default:
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ld->other++;
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break;
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}
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}
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static const value_string type_vals[] = {
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{TYPE_ETHER, "Ethernet"},
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{TYPE_TR, "Token-Ring"},
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{TYPE_FDDI, "FDDI"},
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{TYPE_ATM, "ATM"},
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{0, NULL}
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};
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static const value_string ether_user_vals[] = {
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{0x0, "Normal priority"},
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{0x1, "Priority 1"},
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{0x2, "Priority 2"},
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{0x3, "Highest priority"},
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{0, NULL}
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};
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static const true_false_string bpdu_tfs = {
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"Yes",
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"No"
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};
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static const true_false_string explorer_tfs = {
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"Explorer frame",
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"Data frame"
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};
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static void
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dissect_isl(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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proto_tree *fh_tree = NULL;
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proto_item *ti;
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guint8 type;
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guint16 length;
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gint crc_offset;
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gint captured_length;
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tvbuff_t *next_tvb;
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if (check_col(pinfo->cinfo, COL_PROTOCOL))
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "ISL");
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if (check_col(pinfo->cinfo, COL_INFO))
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col_clear(pinfo->cinfo, COL_INFO);
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type = (tvb_get_guint8(tvb, 5) >> 4)&0x0F;
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if (tree) {
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ti = proto_tree_add_protocol_format(tree, proto_isl, tvb, 0, ISL_HEADER_SIZE,
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"ISL");
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fh_tree = proto_item_add_subtree(ti, ett_isl);
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proto_tree_add_item(fh_tree, hf_isl_dst, tvb, 0, 6, FALSE);
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proto_tree_add_item_hidden(fh_tree, hf_isl_addr, tvb, 0, 6, FALSE);
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proto_tree_add_item(fh_tree, hf_isl_type, tvb, 5, 1, FALSE);
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switch (type) {
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case TYPE_ETHER:
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proto_tree_add_item(fh_tree, hf_isl_user_eth, tvb, 5, 1, FALSE);
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break;
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default:
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/* XXX - the spec appears to indicate that the "User" field is
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used for TYPE_TR to distinguish between types of packets. */
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proto_tree_add_item(fh_tree, hf_isl_user, tvb, 5, 1, FALSE);
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break;
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}
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proto_tree_add_item(fh_tree, hf_isl_src, tvb, 6, 6, FALSE);
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proto_tree_add_item_hidden(fh_tree, hf_isl_addr, tvb, 6, 6, FALSE);
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}
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length = tvb_get_ntohs(tvb, 12);
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if (tree) {
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proto_tree_add_uint(fh_tree, hf_isl_len, tvb, 12, 2, length);
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/* This part looks sort of like a SNAP-encapsulated LLC header... */
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proto_tree_add_text(fh_tree, tvb, 14, 1, "DSAP: 0x%X", tvb_get_guint8(tvb, 14));
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proto_tree_add_text(fh_tree, tvb, 15, 1, "SSAP: 0x%X", tvb_get_guint8(tvb, 15));
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proto_tree_add_text(fh_tree, tvb, 16, 1, "Control: 0x%X", tvb_get_guint8(tvb, 16));
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/* ...but this is the manufacturer's ID portion of the source address
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field (which is, admittedly, an OUI). */
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proto_tree_add_item(fh_tree, hf_isl_hsa, tvb, 17, 3, FALSE);
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}
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if (check_col(pinfo->cinfo, COL_INFO))
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col_add_fstr(pinfo->cinfo, COL_INFO, "VLAN ID: 0x%04X",
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tvb_get_ntohs(tvb, 20) >> 1);
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if (tree) {
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proto_tree_add_item(fh_tree, hf_isl_vlan_id, tvb, 20, 2, FALSE);
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proto_tree_add_item(fh_tree, hf_isl_bpdu, tvb, 20, 2, FALSE);
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proto_tree_add_item(fh_tree, hf_isl_index, tvb, 22, 2, FALSE);
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/* Now for the encapsulated frame's CRC, which is at the *end* of the
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packet; "length" is the length of the frame, not including the
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first 14 bytes of the frame, but including the encapsulated
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frame's CRC, which is 4 bytes long, so the offset of the
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encapsulated CRC is "length + 14 - 4".
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We check for the CRC and display it only if we have that data,
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rather than throwing an exception before we've dissected any
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of the rest of the frame. */
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crc_offset = length + 14 - 4;
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if (tvb_bytes_exist(tvb, crc_offset, 4))
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proto_tree_add_item(fh_tree, hf_isl_crc, tvb, crc_offset, 4, FALSE);
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}
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switch (type) {
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case TYPE_ETHER:
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/* The length of the encapsulated frame is the length from the
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header, minus 12 bytes for the part of the ISL header that
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follows the length and 4 bytes for the encapsulated frame
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CRC. */
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if (length >= 12+4) {
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/* Well, we at least had that much data in the frame. Try
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dissecting what's left as an Ethernet frame. */
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length -= 12+4;
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/* Trim the captured length. */
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captured_length = tvb_length_remaining(tvb, ISL_HEADER_SIZE);
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if (captured_length > 4) {
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/* Subtract the encapsulated frame CRC. */
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captured_length -= 4;
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/* Make sure it's not bigger than the actual length. */
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if (captured_length > length)
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captured_length = length;
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next_tvb = tvb_new_subset(tvb, ISL_HEADER_SIZE, captured_length, length);
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call_dissector(eth_handle, next_tvb, pinfo, tree);
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}
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}
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break;
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case TYPE_TR:
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if (tree) {
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proto_tree_add_item(fh_tree, hf_isl_src_vlan_id, tvb, 24, 2, FALSE);
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proto_tree_add_item(fh_tree, hf_isl_explorer, tvb, 24, 2, FALSE);
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proto_tree_add_item(fh_tree, hf_isl_dst_route_descriptor, tvb, 26, 2, FALSE);
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proto_tree_add_item(fh_tree, hf_isl_src_route_descriptor, tvb, 28, 2, FALSE);
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proto_tree_add_item(fh_tree, hf_isl_fcs_not_incl, tvb, 30, 1, FALSE);
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proto_tree_add_item(fh_tree, hf_isl_esize, tvb, 30, 1, FALSE);
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}
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next_tvb = tvb_new_subset(tvb, 31, -1, -1);
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call_dissector(tr_handle, next_tvb, pinfo, tree);
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break;
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default:
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next_tvb = tvb_new_subset(tvb, ISL_HEADER_SIZE, -1, -1);
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call_dissector(data_handle,next_tvb, pinfo, tree);
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break;
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}
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}
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void
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proto_register_isl(void)
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{
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static hf_register_info hf[] = {
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{ &hf_isl_dst,
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{ "Destination", "isl.dst", FT_ETHER, BASE_NONE, NULL, 0x0,
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"Destination Address", HFILL }},
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{ &hf_isl_type,
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{ "Type", "isl.type", FT_UINT8, BASE_DEC,
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VALS(type_vals), 0xF0, "Type", HFILL }},
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{ &hf_isl_user_eth,
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{ "User", "isl.user_eth", FT_UINT8, BASE_DEC,
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VALS(ether_user_vals), 0x0F, "Priority (for Ethernet)", HFILL }},
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{ &hf_isl_user,
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{ "User", "isl.user", FT_UINT8, BASE_HEX, NULL, 0x0F,
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"User-defined bits", HFILL }},
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{ &hf_isl_src,
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{ "Source", "isl.src", FT_ETHER, BASE_NONE, NULL, 0x0,
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"Source Hardware Address", HFILL }},
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{ &hf_isl_addr,
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{ "Source or Destination Address", "isl.addr", FT_ETHER, BASE_NONE, NULL, 0x0,
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"Source or Destination Hardware Address", HFILL }},
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{ &hf_isl_len,
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{ "Length", "isl.len", FT_UINT16, BASE_DEC, NULL, 0x0,
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"", HFILL }},
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{ &hf_isl_hsa,
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{ "HSA", "isl.hsa", FT_UINT24, BASE_HEX, NULL, 0x0,
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"High bits of source address", HFILL }},
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{ &hf_isl_vlan_id,
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{ "VLAN ID", "isl.vlan_id", FT_UINT16, BASE_HEX, NULL,
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0xFFFE, "Virtual LAN ID", HFILL }},
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{ &hf_isl_bpdu,
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{ "BPDU", "isl.bpdu", FT_BOOLEAN, 16,
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TFS(&bpdu_tfs), 0x0001, "BPDU indicator", HFILL }},
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{ &hf_isl_index,
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{ "Index", "isl.index", FT_UINT16, BASE_DEC, NULL, 0x0,
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"Port index of packet source", HFILL }},
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{ &hf_isl_crc,
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{ "CRC", "isl.crc", FT_UINT32, BASE_HEX, NULL, 0x0,
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"CRC field of encapsulated frame", HFILL }},
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{ &hf_isl_src_vlan_id,
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{ "Source VLAN ID", "isl.src_vlan_id", FT_UINT16, BASE_HEX, NULL,
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0xFFFE, "Source Virtual LAN ID", HFILL }},
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{ &hf_isl_explorer,
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{ "Explorer", "isl.explorer", FT_BOOLEAN, 16,
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TFS(&explorer_tfs), 0x0001, "Explorer", HFILL }},
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{ &hf_isl_dst_route_descriptor,
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{ "Destination route descriptor", "isl.dst_route_desc",
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FT_UINT16, BASE_HEX, NULL, 0x0,
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"Route descriptor to be used for forwarding", HFILL }},
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{ &hf_isl_src_route_descriptor,
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{ "Source-route descriptor", "isl.src_route_desc",
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FT_UINT16, BASE_HEX, NULL, 0x0,
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"Route descriptor to be used for source learning", HFILL }},
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{ &hf_isl_fcs_not_incl,
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{ "FCS Not Included", "isl.fcs_not_incl", FT_BOOLEAN, 9,
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NULL, 0x40, "FCS not included", HFILL }},
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{ &hf_isl_esize,
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{ "Esize", "isl.esize", FT_UINT8, BASE_DEC, NULL,
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0x3F, "Frame size for frames less than 64 bytes", HFILL }},
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};
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static gint *ett[] = {
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&ett_isl,
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};
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proto_isl = proto_register_protocol("Cisco ISL", "ISL", "isl");
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proto_register_field_array(proto_isl, hf, array_length(hf));
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proto_register_subtree_array(ett, array_length(ett));
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register_dissector("isl", dissect_isl, proto_isl);
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}
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void
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proto_reg_handoff_isl(void)
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{
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/*
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* Get handles for the Ethernet and Token Ring dissectors.
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*/
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eth_handle = find_dissector("eth");
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tr_handle = find_dissector("tr");
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data_handle = find_dissector("data");
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}
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