![Guy Harris](/assets/img/avatar_default.png)
"pinfo->current_proto"; dissectors called only through dissector tables and handles don't need to do either of those, as the dissector table and handle code will do it for them. (Dissectors called directly, or dissectors that can be attached to conversations, still have to do it themselves.) Register the PPP Multilink Protocol, PPP Link Control Protocol, and PPP IP Control Protocol as official protocols, and register them in PPP's dissector table rather than having PPP handle them specially; change "dissect_cp()" to take a protocol ID, get the protocol short name information from it, and use the protocol ID for the top-level protocol tree item. Set the Protocol column in the PPP Multilink Protocol dissector, and set the Info column before extracting anything from the frame, so that if an exception is thrown, the Info and Protocol columns will reflect that the packet is supposed to be a PPP Multilink Protocol frame. Make the "First fragment" and "Last fragment" flags in the PPP Multilink Protocol header boolean bitfields, and let "proto_tree_add_boolean()" do all the heavy lifting when displaying them, rather than doing it by hand. Don't extract the sequence number in the PPP Multilink Protocol until you're ready to put it into the tree, just in case the captured packet includes the flags but not the sequence number. Clean up the code to check the FCS of PPP frames - extract it with "tvb_get_letohs()" or "tvb_get_letohl()", don't extract it byte-by-byte and then put it together yourself. svn path=/trunk/; revision=2926
360 lines
11 KiB
C
360 lines
11 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 1.23 2001/01/21 22:10:22 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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#ifdef HAVE_NETINET_IN_H
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# include <netinet/in.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 "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/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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void
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capture_isl(const u_char *pd, int offset, packet_counts *ld)
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{
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guint8 type;
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if (!BYTES_ARE_IN_FRAME(offset, 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, 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, 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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const guint8 *compat_pd;
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int compat_offset;
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if (check_col(pinfo->fd, COL_PROTOCOL))
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col_set_str(pinfo->fd, COL_PROTOCOL, "ISL");
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if (check_col(pinfo->fd, COL_INFO))
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col_clear(pinfo->fd, 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->fd, COL_INFO))
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col_add_fstr(pinfo->fd, 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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/* Set "pinfo"'s payload and captured-payload lengths to the values
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we calculated.
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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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tvb_compat(next_tvb, &compat_pd, &compat_offset);
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pinfo->len = compat_offset + length;
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pinfo->captured_len = compat_offset + captured_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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dissect_data(next_tvb, 0, 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" }},
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{ &hf_isl_type,
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{ "Type", "isl.type", FT_UINT8, BASE_NONE,
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VALS(type_vals), 0xF0, "Type" }},
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{ &hf_isl_user_eth,
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{ "User", "isl.user_eth", FT_UINT8, BASE_NONE,
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VALS(ether_user_vals), 0x0F, "Priority (for Ethernet)" }},
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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" }},
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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" }},
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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" }},
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{ &hf_isl_len,
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{ "Length", "isl.len", FT_UINT16, BASE_DEC, NULL, 0x0,
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"" }},
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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" }},
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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" }},
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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" }},
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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" }},
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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" }},
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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" }},
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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" }},
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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" }},
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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" }},
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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" }},
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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" }},
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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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}
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