forked from osmocom/wireshark
402 lines
12 KiB
C
402 lines
12 KiB
C
/* packet-bvlc.c
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* Routines for BACnet/IP (BVLL, BVLC) dissection
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* Copyright 2001, Hartmut Mueller <hartmut@abmlinux.org>, FH Dortmund
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*
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* $Id: packet-bvlc.c,v 1.14 2004/01/27 03:49:35 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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* Copied from README.developer,v 1.23
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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 <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "prefs.h"
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#include <epan/strutil.h>
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#include <glib.h>
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#include <epan/packet.h>
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static int proto_bvlc = -1;
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static int hf_bvlc_type = -1;
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static int hf_bvlc_function = -1;
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static int hf_bvlc_length = -1;
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static int hf_bvlc_result = -1;
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static int hf_bvlc_bdt_ip = -1;
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static int hf_bvlc_bdt_mask = -1;
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static int hf_bvlc_bdt_port = -1;
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static int hf_bvlc_reg_ttl = -1;
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static int hf_bvlc_fdt_ip = -1;
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static int hf_bvlc_fdt_port = -1;
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static int hf_bvlc_fdt_ttl = -1;
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static int hf_bvlc_fdt_timeout = -1;
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static int hf_bvlc_fwd_ip = -1;
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static int hf_bvlc_fwd_port = -1;
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static dissector_handle_t data_handle;
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static dissector_table_t bvlc_dissector_table;
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static const value_string bvlc_function_names[] = {
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{ 0x00, "BVLC-Result", },
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{ 0x01, "Write-Broadcast-Distribution-Table", },
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{ 0x02, "Read-Broadcast-Distribution-Table", },
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{ 0x03, "Read-Broadcast-Distribution-Table-Ack", },
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{ 0x04, "Forwarded-NPDU", },
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{ 0x05, "Register-Foreign-Device", },
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{ 0x06, "Read-Foreign-Device-Table", },
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{ 0x07, "Read-Foreign-Device-Table-Ack", },
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{ 0x08, "Delete-Foreign-Device-Table-Entry", },
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{ 0x09, "Distribute-Broadcast-To-Network", },
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{ 0x0a, "Original-Unicast-NPDU", },
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{ 0x0b, "Original-Broadcast-NPDU" },
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{ 0, NULL }
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};
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static const value_string bvlc_result_names[] = {
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{ 0x00, "Successful completion" },
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{ 0x10, "Write-Broadcast-Distribution-Table NAK" },
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{ 0x20, "Read-Broadcast-Distribution-Table NAK" },
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{ 0x30, "Register-Foreign-Device NAK" },
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{ 0x40, "Read-Foreign-Device-Table NAK" },
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{ 0x50, "Delete-Foreign-Device-Table-Entry NAK" },
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{ 0x60, "Distribute-Broadcast-To-Network NAK" },
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{ 0, NULL }
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};
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static gint ett_bvlc = -1;
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static gint ett_bdt = -1;
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static gint ett_fdt = -1;
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static void
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dissect_bvlc(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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proto_item *ti;
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proto_item *ti_bdt;
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proto_item *ti_fdt;
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proto_tree *bvlc_tree;
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proto_tree *bdt_tree; /* Broadcast Distribution Table */
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proto_tree *fdt_tree; /* Foreign Device Table */
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gint offset;
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guint8 bvlc_type;
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guint8 bvlc_function;
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guint16 bvlc_length;
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guint16 packet_length;
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guint npdu_length;
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guint16 bvlc_result;
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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, "BVLC");
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if (check_col(pinfo->cinfo, COL_INFO))
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col_set_str(pinfo->cinfo, COL_INFO, "BACnet Virtual Link Control");
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offset = 0;
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bvlc_type = tvb_get_guint8(tvb, offset);
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bvlc_function = tvb_get_guint8(tvb, offset+1);
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packet_length = tvb_get_ntohs(tvb, offset+2);
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if (bvlc_function > 0x08) {
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/* We have a constant header length of BVLC of 4 in every
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* BVLC-packet forewarding an NPDU. Beware: Changes in the
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* BACnet-IP-standard may break this.
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* At the moment, no functions above 0x0b
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* exist (Addendum 135a to ANSI/ASHRAE 135-1995 - BACnet)
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*/
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bvlc_length = 4;
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} else if(bvlc_function == 0x04) {
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/* 4 Bytes + 6 Bytes for B/IP Address of Originating Device */
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bvlc_length = 10;
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} else {
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/* BVLC-packets with function below 0x09 contain
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* routing-level data (e.g. Broadcast Distribution)
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* but no NPDU for BACnet, so bvlc_length goes up to the end
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* of the captured frame.
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*/
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bvlc_length = packet_length;
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}
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if (tree) {
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ti = proto_tree_add_item(tree, proto_bvlc, tvb, 0,
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bvlc_length, FALSE);
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bvlc_tree = proto_item_add_subtree(ti, ett_bvlc);
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proto_tree_add_uint_format(bvlc_tree, hf_bvlc_type, tvb, offset, 1,
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bvlc_type,"Type: 0x%x (Version %s)",bvlc_type,
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(bvlc_type == 0x81)?"BACnet/IP (Annex J)":"unknown");
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offset ++;
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proto_tree_add_uint_format(bvlc_tree, hf_bvlc_function, tvb,
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offset, 1, bvlc_function,"Function: 0x%02x (%s)",
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bvlc_function, val_to_str (bvlc_function,
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bvlc_function_names, "Unknown"));
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offset ++;
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proto_tree_add_uint_format(bvlc_tree, hf_bvlc_length, tvb, offset,
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2, bvlc_length, "BVLC-Length: %d of %d bytes BACnet packet length",
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bvlc_length, packet_length);
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offset += 2;
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switch (bvlc_function) {
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case 0x00: /* BVLC-Result */
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bvlc_result = tvb_get_ntohs(tvb, offset);
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/* I dont know why the result code is encoded in 4 nibbles,
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* but only using one: 0x00r0. Shifting left 4 bits.
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*/
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/* We should bitmask the result correctly when we have a
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* packet to dissect, see README.developer, 1.6.2, FID */
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proto_tree_add_uint_format(bvlc_tree, hf_bvlc_result, tvb,
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offset, 2, bvlc_result,"Result: 0x%04x (%s)",
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bvlc_result, val_to_str(bvlc_result << 4,
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bvlc_result_names, "Unknown"));
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offset += 2;
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break;
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case 0x01: /* Write-Broadcast-Distribution-Table */
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case 0x03: /* Read-Broadcast-Distribution-Table-Ack */
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/* List of BDT Entries: N*10-octet */
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ti_bdt = proto_tree_add_item(bvlc_tree, proto_bvlc, tvb,
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offset, bvlc_length-4, FALSE);
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bdt_tree = proto_item_add_subtree(ti_bdt, ett_bdt);
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/* List of BDT Entries: N*10-octet */
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while ((bvlc_length - offset) > 9) {
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proto_tree_add_item(bdt_tree, hf_bvlc_bdt_ip,
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tvb, offset, 4, FALSE);
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offset += 4;
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proto_tree_add_item(bdt_tree, hf_bvlc_bdt_port,
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tvb, offset, 2, FALSE);
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offset += 2;
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proto_tree_add_item(bdt_tree,
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hf_bvlc_bdt_mask, tvb, offset, 4,
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FALSE);
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offset += 4;
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}
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/* We check this if we get a BDT-packet somewhere */
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break;
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case 0x02: /* Read-Broadcast-Distribution-Table */
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/* nothing to do here */
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break;
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case 0x05: /* Register-Foreign-Device */
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/* Time-to-Live 2-octets T, Time-to-Live T, in seconds */
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proto_tree_add_item(bvlc_tree, hf_bvlc_reg_ttl,
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tvb, offset, 2, FALSE);
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offset += 2;
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break;
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case 0x06: /* Read-Foreign-Device-Table */
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/* nothing to do here */
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break;
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case 0x07: /* Read-Foreign-Device-Table-Ack */
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/* List of FDT Entries: N*10-octet */
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/* N indicates the number of entries in the FDT whose
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* contents are being returned. Each returned entry
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* consists of the 6-octet B/IP address of the registrant;
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* the 2-octet Time-to-Live value supplied at the time of
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* registration; and a 2-octet value representing the
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* number of seconds remaining before the BBMD will purge
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* the registrant's FDT entry if no re-registration occurs.
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*/
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ti_fdt = proto_tree_add_item(bvlc_tree, proto_bvlc, tvb,
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offset, bvlc_length -4, FALSE);
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fdt_tree = proto_item_add_subtree(ti_fdt, ett_fdt);
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/* List of FDT Entries: N*10-octet */
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while ((bvlc_length - offset) > 9) {
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proto_tree_add_item(fdt_tree, hf_bvlc_fdt_ip,
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tvb, offset, 4, FALSE);
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offset += 4;
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proto_tree_add_item(fdt_tree, hf_bvlc_fdt_port,
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tvb, offset, 2, FALSE);
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offset += 2;
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proto_tree_add_item(fdt_tree,
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hf_bvlc_fdt_ttl, tvb, offset, 2,
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FALSE);
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offset += 2;
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proto_tree_add_item(fdt_tree,
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hf_bvlc_fdt_timeout, tvb, offset, 2,
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FALSE);
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offset += 2;
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}
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/* We check this if we get a FDT-packet somewhere */
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break;
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case 0x08: /* Delete-Foreign-Device-Table-Entry */
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/* FDT Entry: 6-octets */
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proto_tree_add_item(bvlc_tree, hf_bvlc_fdt_ip,
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tvb, offset, 4, FALSE);
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offset += 4;
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proto_tree_add_item(bvlc_tree, hf_bvlc_fdt_port,
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tvb, offset, 2, FALSE);
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offset += 2;
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break;
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/* We check this if we get a FDT-packet somewhere */
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case 0x04: /* Forwarded-NPDU
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* Why is this 0x04? It would have been a better
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* idea to append all forewarded NPDUs at the
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* end of the function table in the B/IP-standard!
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*/
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/* proto_tree_add_bytes_format(); */
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proto_tree_add_item(bvlc_tree, hf_bvlc_fwd_ip,
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tvb, offset, 4, FALSE);
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offset += 4;
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proto_tree_add_item(bvlc_tree, hf_bvlc_fwd_port,
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tvb, offset, 2, FALSE);
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offset += 2;
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default:/* Distribute-Broadcast-To-Network
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* Original-Unicast-NPDU
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* Original-Broadcast-NPDU
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* Going to the next dissector...
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*/
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break;
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}
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}
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/* Ok, no routing information BVLC packet. Dissect as
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* BACnet NPDU
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*/
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npdu_length = packet_length - bvlc_length;
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next_tvb = tvb_new_subset(tvb,bvlc_length,-1,npdu_length);
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/* Code from Guy Harris */
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if (!dissector_try_port(bvlc_dissector_table,
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bvlc_function, next_tvb, pinfo, tree)) {
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/* Unknown function - dissect the paylod as data */
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call_dissector(data_handle,next_tvb, pinfo, tree);
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}
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}
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void
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proto_register_bvlc(void)
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{
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static hf_register_info hf[] = {
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{ &hf_bvlc_type,
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{ "Type", "bvlc.type",
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FT_UINT8, BASE_HEX, NULL, 0,
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"Type", HFILL }
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},
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{ &hf_bvlc_function,
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{ "Function", "bvlc.function",
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FT_UINT8, BASE_HEX, NULL, 0,
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"BLVC Function", HFILL }
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},
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{ &hf_bvlc_length,
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{ "Length", "bvlc.length",
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FT_UINT16, BASE_DEC, NULL, 0,
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"Length of BVLC", HFILL }
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},
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/* We should bitmask the result correctly when we have a
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* packet to dissect */
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{ &hf_bvlc_result,
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{ "Result", "bvlc.result",
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FT_UINT16, BASE_HEX, NULL, 0xffff,
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"Result Code", HFILL }
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},
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{ &hf_bvlc_bdt_ip,
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{ "IP", "bvlc.bdt_ip",
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FT_IPv4, BASE_NONE, NULL, 0,
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"BDT IP", HFILL }
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},
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{ &hf_bvlc_bdt_port,
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{ "Port", "bvlc.bdt_port",
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FT_UINT16, BASE_DEC, NULL, 0,
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"BDT Port", HFILL }
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},
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{ &hf_bvlc_bdt_mask,
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{ "Mask", "bvlc.bdt_mask",
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FT_BYTES, BASE_HEX, NULL, 0,
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"BDT Broadcast Distribution Mask", HFILL }
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},
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{ &hf_bvlc_reg_ttl,
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{ "TTL", "bvlc.reg_ttl",
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FT_UINT16, BASE_DEC, NULL, 0,
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"Foreign Device Time To Live", HFILL }
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},
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{ &hf_bvlc_fdt_ip,
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{ "IP", "bvlc.fdt_ip",
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FT_IPv4, BASE_NONE, NULL, 0,
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"FDT IP", HFILL }
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},
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{ &hf_bvlc_fdt_port,
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{ "Port", "bvlc.fdt_port",
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FT_UINT16, BASE_DEC, NULL, 0,
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"FDT Port", HFILL }
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},
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{ &hf_bvlc_fdt_ttl,
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{ "TTL", "bvlc.fdt_ttl",
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FT_UINT16, BASE_DEC, NULL, 0,
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"Foreign Device Time To Live", HFILL }
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},
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{ &hf_bvlc_fdt_timeout,
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{ "Timeout", "bvlc.fdt_timeout",
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FT_UINT16, BASE_DEC, NULL, 0,
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"Foreign Device Timeout (seconds)", HFILL }
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},
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{ &hf_bvlc_fwd_ip,
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{ "IP", "bvlc.fwd_ip",
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FT_IPv4, BASE_NONE, NULL, 0,
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"FWD IP", HFILL }
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},
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{ &hf_bvlc_fwd_port,
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{ "Port", "bvlc.fwd_port",
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FT_UINT16, BASE_DEC, NULL, 0,
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"FWD Port", HFILL }
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},
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};
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static gint *ett[] = {
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&ett_bvlc,
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&ett_bdt,
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&ett_fdt,
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};
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proto_bvlc = proto_register_protocol("BACnet Virtual Link Control",
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"BVLC", "bvlc");
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proto_register_field_array(proto_bvlc, hf, array_length(hf));
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proto_register_subtree_array(ett, array_length(ett));
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register_dissector("bvlc", dissect_bvlc, proto_bvlc);
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bvlc_dissector_table = register_dissector_table("bvlc.function",
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"BVLC Function", FT_UINT8, BASE_HEX);
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}
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void
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proto_reg_handoff_bvlc(void)
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{
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dissector_handle_t bvlc_handle;
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bvlc_handle = find_dissector("bvlc");
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dissector_add("udp.port", 0xBAC0, bvlc_handle);
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data_handle = find_dissector("data");
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}
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/* Taken from add-135a (BACnet-IP-standard paper):
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*
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* The default UDP port for both directed messages and broadcasts shall
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* be X'BAC0' and all B/IP devices shall support it. In some cases,
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* e.g., a situation where it is desirable for two groups of BACnet devices
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* to coexist independently on the same IP subnet, the UDP port may be
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* configured locally to a different value without it being considered
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* a violation of this protocol.
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*
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* This dissector does not analyse UDP packets other than on port 0xBAC0.
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* If you changed your BACnet port locally, use the ethereal feature
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* "Decode As".
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*/
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