2 * Routines for BACnet/IP (BVLL, BVLC) dissection
3 * Copyright 2001, Hartmut Mueller <hartmut@abmlinux.org>, FH Dortmund
5 * $Id: packet-bvlc.c,v 1.13 2002/08/28 21:00:08 jmayer Exp $
7 * Ethereal - Network traffic analyzer
8 * By Gerald Combs <gerald@ethereal.com>
9 * Copyright 1998 Gerald Combs
11 * Copied from README.developer,v 1.23
13 * This program is free software; you can redistribute it and/or
14 * modify it under the terms of the GNU General Public License
15 * as published by the Free Software Foundation; either version 2
16 * of the License, or (at your option) any later version.
18 * This program is distributed in the hope that it will be useful,
19 * but WITHOUT ANY WARRANTY; without even the implied warranty of
20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 * GNU General Public License for more details.
23 * You should have received a copy of the GNU General Public License
24 * along with this program; if not, write to the Free Software
25 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
36 #include <epan/strutil.h>
40 #include <epan/packet.h>
42 static int proto_bvlc = -1;
43 static int hf_bvlc_type = -1;
44 static int hf_bvlc_function = -1;
45 static int hf_bvlc_length = -1;
46 static int hf_bvlc_result = -1;
47 static int hf_bvlc_bdt_ip = -1;
48 static int hf_bvlc_bdt_mask = -1;
49 static int hf_bvlc_bdt_port = -1;
50 static int hf_bvlc_reg_ttl = -1;
51 static int hf_bvlc_fdt_ip = -1;
52 static int hf_bvlc_fdt_port = -1;
53 static int hf_bvlc_fdt_ttl = -1;
54 static int hf_bvlc_fdt_timeout = -1;
55 static int hf_bvlc_fwd_ip = -1;
56 static int hf_bvlc_fwd_port = -1;
58 static dissector_handle_t data_handle;
60 static dissector_table_t bvlc_dissector_table;
62 static const value_string bvlc_function_names[] = {
63 { 0x00, "BVLC-Result", },
64 { 0x01, "Write-Broadcast-Distribution-Table", },
65 { 0x02, "Read-Broadcast-Distribution-Table", },
66 { 0x03, "Read-Broadcast-Distribution-Table-Ack", },
67 { 0x04, "Forwarded-NPDU", },
68 { 0x05, "Register-Foreign-Device", },
69 { 0x06, "Read-Foreign-Device-Table", },
70 { 0x07, "Read-Foreign-Device-Table-Ack", },
71 { 0x08, "Delete-Foreign-Device-Table-Entry", },
72 { 0x09, "Distribute-Broadcast-To-Network", },
73 { 0x0a, "Original-Unicast-NPDU", },
74 { 0x0b, "Original-Broadcast-NPDU" },
78 static const value_string bvlc_result_names[] = {
79 { 0x00, "Successful completion" },
80 { 0x10, "Write-Broadcast-Distribution-Table NAK" },
81 { 0x20, "Read-Broadcast-Distribution-Table NAK" },
82 { 0x30, "Register-Foreign-Device NAK" },
83 { 0x40, "Read-Foreign-Device-Table NAK" },
84 { 0x50, "Delete-Foreign-Device-Table-Entry NAK" },
85 { 0x60, "Distribute-Broadcast-To-Network NAK" },
89 static gint ett_bvlc = -1;
90 static gint ett_bdt = -1;
91 static gint ett_fdt = -1;
94 dissect_bvlc(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
100 proto_tree *bvlc_tree;
101 proto_tree *bdt_tree; /* Broadcast Distribution Table */
102 proto_tree *fdt_tree; /* Foreign Device Table */
106 guint8 bvlc_function;
108 guint16 packet_length;
113 if (check_col(pinfo->cinfo, COL_PROTOCOL))
114 col_set_str(pinfo->cinfo, COL_PROTOCOL, "BVLC");
116 if (check_col(pinfo->cinfo, COL_INFO))
117 col_set_str(pinfo->cinfo, COL_INFO, "BACnet Virtual Link Control");
121 bvlc_type = tvb_get_guint8(tvb, offset);
122 bvlc_function = tvb_get_guint8(tvb, offset+1);
123 packet_length = tvb_get_ntohs(tvb, offset+2);
124 if (bvlc_function > 0x08) {
125 /* We have a constant header length of BVLC of 4 in every
126 * BVLC-packet forewarding an NPDU. Beware: Changes in the
127 * BACnet-IP-standard may break this.
128 * At the moment, no functions above 0x0b
129 * exist (Addendum 135a to ANSI/ASHRAE 135-1995 - BACnet)
132 } else if(bvlc_function == 0x04) {
133 /* 4 Bytes + 6 Bytes for B/IP Address of Originating Device */
136 /* BVLC-packets with function below 0x09 contain
137 * routing-level data (e.g. Broadcast Distribution)
138 * but no NPDU for BACnet, so bvlc_length goes up to the end
139 * of the captured frame.
141 bvlc_length = packet_length;
145 ti = proto_tree_add_item(tree, proto_bvlc, tvb, 0,
147 bvlc_tree = proto_item_add_subtree(ti, ett_bvlc);
148 proto_tree_add_uint_format(bvlc_tree, hf_bvlc_type, tvb, offset, 1,
149 bvlc_type,"Type: 0x%x (Version %s)",bvlc_type,
150 (bvlc_type == 0x81)?"BACnet/IP (Annex J)":"unknown");
152 proto_tree_add_uint_format(bvlc_tree, hf_bvlc_function, tvb,
153 offset, 1, bvlc_function,"Function: 0x%02x (%s)",
154 bvlc_function, val_to_str (bvlc_function,
155 bvlc_function_names, "Unknown"));
157 proto_tree_add_uint_format(bvlc_tree, hf_bvlc_length, tvb, offset,
158 2, bvlc_length, "BVLC-Length: %d of %d bytes BACnet packet length",
159 bvlc_length, packet_length);
161 switch (bvlc_function) {
162 case 0x00: /* BVLC-Result */
163 bvlc_result = tvb_get_ntohs(tvb, offset);
164 /* I dont know why the result code is encoded in 4 nibbles,
165 * but only using one: 0x00r0. Shifting left 4 bits.
167 /* We should bitmask the result correctly when we have a
168 * packet to dissect, see README.developer, 1.6.2, FID */
169 proto_tree_add_uint_format(bvlc_tree, hf_bvlc_result, tvb,
170 offset, 2, bvlc_result,"Result: 0x%04x (%s)",
171 bvlc_result, val_to_str(bvlc_result << 4,
172 bvlc_result_names, "Unknown"));
175 case 0x01: /* Write-Broadcast-Distribution-Table */
176 case 0x03: /* Read-Broadcast-Distribution-Table-Ack */
177 /* List of BDT Entries: N*10-octet */
178 ti_bdt = proto_tree_add_item(bvlc_tree, proto_bvlc, tvb,
179 offset, bvlc_length-4, FALSE);
180 bdt_tree = proto_item_add_subtree(ti_bdt, ett_bdt);
181 /* List of BDT Entries: N*10-octet */
182 while ((bvlc_length - offset) > 9) {
183 proto_tree_add_item(bdt_tree, hf_bvlc_bdt_ip,
184 tvb, offset, 4, FALSE);
186 proto_tree_add_item(bdt_tree, hf_bvlc_bdt_port,
187 tvb, offset, 2, FALSE);
189 proto_tree_add_item(bdt_tree,
190 hf_bvlc_bdt_mask, tvb, offset, 4,
194 /* We check this if we get a BDT-packet somewhere */
196 case 0x02: /* Read-Broadcast-Distribution-Table */
197 /* nothing to do here */
199 case 0x05: /* Register-Foreign-Device */
200 /* Time-to-Live 2-octets T, Time-to-Live T, in seconds */
201 proto_tree_add_item(bvlc_tree, hf_bvlc_reg_ttl,
202 tvb, offset, 2, FALSE);
205 case 0x06: /* Read-Foreign-Device-Table */
206 /* nothing to do here */
208 case 0x07: /* Read-Foreign-Device-Table-Ack */
209 /* List of FDT Entries: N*10-octet */
210 /* N indicates the number of entries in the FDT whose
211 * contents are being returned. Each returned entry
212 * consists of the 6-octet B/IP address of the registrant;
213 * the 2-octet Time-to-Live value supplied at the time of
214 * registration; and a 2-octet value representing the
215 * number of seconds remaining before the BBMD will purge
216 * the registrant's FDT entry if no re-registration occurs.
218 ti_fdt = proto_tree_add_item(bvlc_tree, proto_bvlc, tvb,
219 offset, bvlc_length -4, FALSE);
220 fdt_tree = proto_item_add_subtree(ti_fdt, ett_fdt);
221 /* List of FDT Entries: N*10-octet */
222 while ((bvlc_length - offset) > 9) {
223 proto_tree_add_item(fdt_tree, hf_bvlc_fdt_ip,
224 tvb, offset, 4, FALSE);
226 proto_tree_add_item(fdt_tree, hf_bvlc_fdt_port,
227 tvb, offset, 2, FALSE);
229 proto_tree_add_item(fdt_tree,
230 hf_bvlc_fdt_ttl, tvb, offset, 2,
233 proto_tree_add_item(fdt_tree,
234 hf_bvlc_fdt_timeout, tvb, offset, 2,
238 /* We check this if we get a FDT-packet somewhere */
240 case 0x08: /* Delete-Foreign-Device-Table-Entry */
241 /* FDT Entry: 6-octets */
242 proto_tree_add_item(bvlc_tree, hf_bvlc_fdt_ip,
243 tvb, offset, 4, FALSE);
245 proto_tree_add_item(bvlc_tree, hf_bvlc_fdt_port,
246 tvb, offset, 2, FALSE);
249 /* We check this if we get a FDT-packet somewhere */
250 case 0x04: /* Forwarded-NPDU
251 * Why is this 0x04? It would have been a better
252 * idea to append all forewarded NPDUs at the
253 * end of the function table in the B/IP-standard!
255 /* proto_tree_add_bytes_format(); */
256 proto_tree_add_item(bvlc_tree, hf_bvlc_fwd_ip,
257 tvb, offset, 4, FALSE);
259 proto_tree_add_item(bvlc_tree, hf_bvlc_fwd_port,
260 tvb, offset, 2, FALSE);
262 default:/* Distribute-Broadcast-To-Network
263 * Original-Unicast-NPDU
264 * Original-Broadcast-NPDU
265 * Going to the next dissector...
271 /* Ok, no routing information BVLC packet. Dissect as
274 npdu_length = packet_length - bvlc_length;
275 next_tvb = tvb_new_subset(tvb,bvlc_length,-1,npdu_length);
276 /* Code from Guy Harris */
277 if (!dissector_try_port(bvlc_dissector_table,
278 bvlc_function, next_tvb, pinfo, tree)) {
279 /* Unknown function - dissect the paylod as data */
280 call_dissector(data_handle,next_tvb, pinfo, tree);
285 proto_register_bvlc(void)
287 static hf_register_info hf[] = {
289 { "Type", "bvlc.type",
290 FT_UINT8, BASE_HEX, NULL, 0,
294 { "Function", "bvlc.function",
295 FT_UINT8, BASE_HEX, NULL, 0,
296 "BLVC Function", HFILL }
299 { "Length", "bvlc.length",
300 FT_UINT16, BASE_DEC, NULL, 0,
301 "Length of BVLC", HFILL }
303 /* We should bitmask the result correctly when we have a
304 * packet to dissect */
306 { "Result", "bvlc.result",
307 FT_UINT16, BASE_HEX, NULL, 0xffff,
308 "Result Code", HFILL }
311 { "IP", "bvlc.bdt_ip",
312 FT_IPv4, BASE_NONE, NULL, 0,
316 { "Port", "bvlc.bdt_port",
317 FT_UINT16, BASE_DEC, NULL, 0,
321 { "Mask", "bvlc.bdt_mask",
322 FT_BYTES, BASE_HEX, NULL, 0,
323 "BDT Broadcast Distribution Mask", HFILL }
326 { "TTL", "bvlc.reg_ttl",
327 FT_UINT16, BASE_DEC, NULL, 0,
328 "Foreign Device Time To Live", HFILL }
331 { "IP", "bvlc.fdt_ip",
332 FT_IPv4, BASE_NONE, NULL, 0,
336 { "Port", "bvlc.fdt_port",
337 FT_UINT16, BASE_DEC, NULL, 0,
341 { "TTL", "bvlc.fdt_ttl",
342 FT_UINT16, BASE_DEC, NULL, 0,
343 "Foreign Device Time To Live", HFILL }
345 { &hf_bvlc_fdt_timeout,
346 { "Timeout", "bvlc.fdt_timeout",
347 FT_UINT16, BASE_DEC, NULL, 0,
348 "Foreign Device Timeout (seconds)", HFILL }
351 { "IP", "bvlc.fwd_ip",
352 FT_IPv4, BASE_NONE, NULL, 0,
356 { "Port", "bvlc.fwd_port",
357 FT_UINT16, BASE_DEC, NULL, 0,
362 static gint *ett[] = {
368 proto_bvlc = proto_register_protocol("BACnet Virtual Link Control",
371 proto_register_field_array(proto_bvlc, hf, array_length(hf));
372 proto_register_subtree_array(ett, array_length(ett));
374 register_dissector("bvlc", dissect_bvlc, proto_bvlc);
376 bvlc_dissector_table = register_dissector_table("bvlc.function",
377 "BVLC Function", FT_UINT8, BASE_HEX);
381 proto_reg_handoff_bvlc(void)
383 dissector_handle_t bvlc_handle;
385 bvlc_handle = find_dissector("bvlc");
386 dissector_add("udp.port", 0xBAC0, bvlc_handle);
387 data_handle = find_dissector("data");
389 /* Taken from add-135a (BACnet-IP-standard paper):
391 * The default UDP port for both directed messages and broadcasts shall
392 * be X'BAC0' and all B/IP devices shall support it. In some cases,
393 * e.g., a situation where it is desirable for two groups of BACnet devices
394 * to coexist independently on the same IP subnet, the UDP port may be
395 * configured locally to a different value without it being considered
396 * a violation of this protocol.
398 * This dissector does not analyse UDP packets other than on port 0xBAC0.
399 * If you changed your BACnet port locally, use the ethereal feature