packet-bvlc.c

   1 /* packet-bvlc.c
   2  * Routines for BACnet/IP (BVLL, BVLC) dissection
   3  * Copyright 2001, Hartmut Mueller <hartmut@abmlinux.org>, FH Dortmund
   4  *
   5  * $Id: packet-bvlc.c,v 1.10 2002/06/05 00:03:06 gerald Exp $
   6  *
   7  * Ethereal - Network traffic analyzer
   8  * By Gerald Combs <gerald@ethereal.com>
   9  * Copyright 1998 Gerald Combs
  10  *
  11  * Copied from README.developer,v 1.23
  12  *
  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.
  17  *
  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.
  22  *
  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.
  26  */
  27
  28 #ifdef HAVE_CONFIG_H
  29 # include "config.h"
  30 #endif
  31
  32 #include <stdio.h>
  33 #include <stdlib.h>
  34 #include <string.h>
  35 #include "prefs.h"
  36 #include <epan/strutil.h>
  37
  38 #ifdef HAVE_SYS_TYPES_H
  39 # include <sys/types.h>
  40 #endif
  41
  42 #ifdef HAVE_NETINET_IN_H
  43 # include <netinet/in.h>
  44 #endif
  45
  46 #include <glib.h>
  47
  48 #ifdef NEED_SNPRINTF_H
  49 # include "snprintf.h"
  50 #endif
  51
  52 #include <epan/packet.h>
  53
  54 static int proto_bvlc = -1;
  55 static int hf_bvlc_type = -1;
  56 static int hf_bvlc_function = -1;
  57 static int hf_bvlc_length = -1;
  58 static int hf_bvlc_result = -1;
  59 static int hf_bvlc_bdt_ip = -1;
  60 static int hf_bvlc_bdt_mask = -1;
  61 static int hf_bvlc_bdt_port = -1;
  62 static int hf_bvlc_reg_ttl = -1;
  63 static int hf_bvlc_fdt_ip = -1;
  64 static int hf_bvlc_fdt_port = -1;
  65 static int hf_bvlc_fdt_ttl = -1;
  66 static int hf_bvlc_fdt_timeout = -1;
  67 static int hf_bvlc_fwd_ip = -1;
  68 static int hf_bvlc_fwd_port = -1;
  69
  70 static dissector_handle_t data_handle;
  71
  72 static dissector_table_t bvlc_dissector_table;
  73
  74 static const value_string bvlc_function_names[] = {
  75         { 0x00, "BVLC-Result", },
  76         { 0x01, "Write-Broadcast-Distribution-Table", },
  77         { 0x02, "Read-Broadcast-Distribution-Table", },
  78         { 0x03, "Read-Broadcast-Distribution-Table-Ack", },
  79         { 0x04, "Forwarded-NPDU", },
  80         { 0x05, "Register-Foreign-Device", },
  81         { 0x06, "Read-Foreign-Device-Table", },
  82         { 0x07, "Read-Foreign-Device-Table-Ack", },
  83         { 0x08, "Delete-Foreign-Device-Table-Entry", },
  84         { 0x09, "Distribute-Broadcast-To-Network", },
  85         { 0x0a, "Original-Unicast-NPDU", },
  86         { 0x0b, "Original-Broadcast-NPDU" },
  87         { 0,    NULL }
  88 };
  89
  90 static const value_string bvlc_result_names[] = {
  91         { 0x00, "Successful completion" },
  92         { 0x10, "Write-Broadcast-Distribution-Table NAK" },
  93         { 0x20, "Read-Broadcast-Distribution-Table NAK" },
  94         { 0x30, "Register-Foreign-Device NAK" },
  95         { 0x40, "Read-Foreign-Device-Table NAK" },
  96         { 0x50, "Delete-Foreign-Device-Table-Entry NAK" },
  97         { 0x60, "Distribute-Broadcast-To-Network NAK" },
  98         { 0,    NULL }
  99 };
 100
 101 static gint ett_bvlc = -1;
 102 static gint ett_bdt = -1;
 103 static gint ett_fdt = -1;
 104
 105 static void
 106 dissect_bvlc(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 107 {
 108
 109         proto_item *ti;
 110         proto_item *ti_bdt;
 111         proto_item *ti_fdt;
 112         proto_tree *bvlc_tree;
 113         proto_tree *bdt_tree; /* Broadcast Distribution Table */
 114         proto_tree *fdt_tree; /* Foreign Device Table */
 115
 116         gint offset;
 117         guint8 bvlc_type;
 118         guint8 bvlc_function;
 119         guint16 bvlc_length;
 120         guint16 packet_length;
 121         guint8 npdu_length;
 122         guint16 bvlc_result;
 123         tvbuff_t *next_tvb;
 124
 125         if (check_col(pinfo->cinfo, COL_PROTOCOL))
 126                 col_set_str(pinfo->cinfo, COL_PROTOCOL, "BVLC");
 127
 128         if (check_col(pinfo->cinfo, COL_INFO))
 129                 col_set_str(pinfo->cinfo, COL_INFO, "BACnet Virtual Link Control");
 130
 131         offset = 0;
 132
 133         bvlc_type =  tvb_get_guint8(tvb, offset);
 134         bvlc_function = tvb_get_guint8(tvb, offset+1);
 135         packet_length = tvb_get_ntohs(tvb, offset+2);
 136         if (bvlc_function > 0x08) {
 137                 /*  We have a constant header length of BVLC of 4 in every
 138                  *  BVLC-packet forewarding an NPDU. Beware: Changes in the
 139                  *  BACnet-IP-standard may break this.
 140                  *  At the moment, no functions above 0x0b
 141                  *  exist (Addendum 135a to ANSI/ASHRAE 135-1995 - BACnet)
 142                  */
 143                 bvlc_length = 4;
 144         } else if(bvlc_function == 0x04) {
 145                 /* 4 Bytes + 6 Bytes for B/IP Address of Originating Device */
 146                 bvlc_length = 10;
 147         } else {
 148                 /*  BVLC-packets with function below 0x09 contain
 149                  *  routing-level data (e.g. Broadcast Distribution)
 150                  *  but no NPDU for BACnet, so bvlc_length goes up to the end
 151                  *  of the captured frame.
 152                  */
 153                 bvlc_length = packet_length;
 154         }
 155
 156         if (tree) {
 157                 ti = proto_tree_add_item(tree, proto_bvlc, tvb, 0,
 158                         bvlc_length, FALSE);
 159                 bvlc_tree = proto_item_add_subtree(ti, ett_bvlc);
 160                 proto_tree_add_uint_format(bvlc_tree, hf_bvlc_type, tvb, offset, 1,
 161                         bvlc_type,"Type: 0x%x (Version %s)",bvlc_type,
 162                         (bvlc_type == 0x81)?"BACnet/IP (Annex J)":"unknown");
 163                 offset ++;
 164                 proto_tree_add_uint_format(bvlc_tree, hf_bvlc_function, tvb,
 165                         offset, 1, bvlc_function,"Function: 0x%02x (%s)",
 166                         bvlc_function, val_to_str (bvlc_function,
 167                                 bvlc_function_names, "Unknown"));
 168                 offset ++;
 169                 proto_tree_add_uint_format(bvlc_tree, hf_bvlc_length, tvb, offset,
 170                         2, bvlc_length, "BVLC-Length: %d of %d bytes BACnet packet length",
 171                         bvlc_length, packet_length);
 172                 offset += 2;
 173                 switch (bvlc_function) {
 174                 case 0x00: /* BVLC-Result */
 175                         bvlc_result = tvb_get_ntohs(tvb, offset);
 176                         /* I dont know why the result code is encoded in 4 nibbles,
 177                          * but only using one: 0x00r0. Shifting left 4 bits.
 178                          */
 179                         /* We should bitmask the result correctly when we have a
 180                         * packet to dissect, see README.developer, 1.6.2, FID */
 181                         proto_tree_add_uint_format(bvlc_tree, hf_bvlc_result, tvb,
 182                                 offset, 2, bvlc_result,"Result: 0x%04x (%s)",
 183                                 bvlc_result, val_to_str(bvlc_result << 4,
 184                                         bvlc_result_names, "Unknown"));
 185                         offset += 2;
 186                         break;
 187                 case 0x01: /* Write-Broadcast-Distribution-Table */
 188                 case 0x03: /* Read-Broadcast-Distribution-Table-Ack */
 189                         /* List of BDT Entries: N*10-octet */
 190                         ti_bdt = proto_tree_add_item(bvlc_tree, proto_bvlc, tvb,
 191                                 offset, bvlc_length-4, FALSE);
 192                         bdt_tree = proto_item_add_subtree(ti_bdt, ett_bdt);
 193                         /* List of BDT Entries: N*10-octet */
 194                         while ((bvlc_length - offset) > 9) {
 195                                 proto_tree_add_item(bdt_tree, hf_bvlc_bdt_ip,
 196                                         tvb, offset, 4, FALSE);
 197                                 offset += 4;
 198                                 proto_tree_add_item(bdt_tree, hf_bvlc_bdt_port,
 199                                         tvb, offset, 2, FALSE);
 200                                 offset += 2;
 201                                 proto_tree_add_item(bdt_tree,
 202                                         hf_bvlc_bdt_mask, tvb, offset, 4,
 203                                         FALSE);
 204                                 offset += 4;
 205                         }
 206                         /* We check this if we get a BDT-packet somewhere */
 207                         break;
 208                 case 0x02: /* Read-Broadcast-Distribution-Table */
 209                         /* nothing to do here */
 210                         break;
 211                 case 0x05: /* Register-Foreign-Device */
 212                         /* Time-to-Live 2-octets T, Time-to-Live T, in seconds */
 213                         proto_tree_add_item(bvlc_tree, hf_bvlc_reg_ttl,
 214                                 tvb, offset, 2, FALSE);
 215                         offset += 2;
 216                         break;
 217                 case 0x06: /* Read-Foreign-Device-Table */
 218                         /* nothing to do here */
 219                         break;
 220                 case 0x07: /* Read-Foreign-Device-Table-Ack */
 221                         /* List of FDT Entries: N*10-octet */
 222                         /* N indicates the number of entries in the FDT whose
 223                          * contents are being returned. Each returned entry
 224                          * consists of the 6-octet B/IP address of the registrant;
 225                          * the 2-octet Time-to-Live value supplied at the time of
 226                          * registration; and a 2-octet value representing the
 227                          * number of seconds remaining before the BBMD will purge
 228                          * the registrant's FDT entry if no re-registration occurs.
 229                          */
 230                         ti_fdt = proto_tree_add_item(bvlc_tree, proto_bvlc, tvb,
 231                                 offset, bvlc_length -4, FALSE);
 232                         fdt_tree = proto_item_add_subtree(ti_fdt, ett_fdt);
 233                         /* List of FDT Entries: N*10-octet */
 234                         while ((bvlc_length - offset) > 9) {
 235                                 proto_tree_add_item(fdt_tree, hf_bvlc_fdt_ip,
 236                                         tvb, offset, 4, FALSE);
 237                                 offset += 4;
 238                                 proto_tree_add_item(fdt_tree, hf_bvlc_fdt_port,
 239                                         tvb, offset, 2, FALSE);
 240                                 offset += 2;
 241                                 proto_tree_add_item(fdt_tree,
 242                                         hf_bvlc_fdt_ttl, tvb, offset, 2,
 243                                         FALSE);
 244                                 offset += 2;
 245                                 proto_tree_add_item(fdt_tree,
 246                                         hf_bvlc_fdt_timeout, tvb, offset, 2,
 247                                         FALSE);
 248                                 offset += 2;
 249                         }
 250                         /* We check this if we get a FDT-packet somewhere */
 251                         break;
 252                 case 0x08: /* Delete-Foreign-Device-Table-Entry */
 253                         /* FDT Entry:   6-octets */
 254                         proto_tree_add_item(bvlc_tree, hf_bvlc_fdt_ip,
 255                                 tvb, offset, 4, FALSE);
 256                         offset += 4;
 257                         proto_tree_add_item(bvlc_tree, hf_bvlc_fdt_port,
 258                                 tvb, offset, 2, FALSE);
 259                         offset += 2;
 260                         break;
 261                         /* We check this if we get a FDT-packet somewhere */
 262                 case 0x04:      /* Forwarded-NPDU
 263                                  * Why is this 0x04? It would have been a better
 264                                  * idea to append all forewarded NPDUs at the
 265                                  * end of the function table in the B/IP-standard!
 266                                  */
 267                         /* proto_tree_add_bytes_format(); */
 268                         proto_tree_add_item(bvlc_tree, hf_bvlc_fwd_ip,
 269                                 tvb, offset, 4, FALSE);
 270                         offset += 4;
 271                         proto_tree_add_item(bvlc_tree, hf_bvlc_fwd_port,
 272                                 tvb, offset, 2, FALSE);
 273                         offset += 2;
 274                 default:/* Distribute-Broadcast-To-Network
 275                          * Original-Unicast-NPDU
 276                          * Original-Broadcast-NPDU
 277                          * Going to the next dissector...
 278                          */
 279                         break;
 280                 }
 281
 282         }
 283 /* Ok, no routing information BVLC packet. Dissect as
 284  * BACnet NPDU
 285  */
 286         npdu_length = packet_length - bvlc_length;
 287         next_tvb = tvb_new_subset(tvb,bvlc_length,-1,npdu_length);
 288         /* Code from Guy Harris */
 289         if (!dissector_try_port(bvlc_dissector_table,
 290         bvlc_function, next_tvb, pinfo, tree)) {
 291                 /* Unknown function - dissect the paylod as data */
 292                 call_dissector(data_handle,next_tvb, pinfo, tree);
 293         }
 294 }
 295
 296 void
 297 proto_register_bvlc(void)
 298 {
 299         static hf_register_info hf[] = {
 300                 { &hf_bvlc_type,
 301                         { "Type",           "bvlc.type",
 302                         FT_UINT8, BASE_HEX, NULL, 0,
 303                         "Type", HFILL }
 304                 },
 305                 { &hf_bvlc_function,
 306                         { "Function",           "bvlc.function",
 307                         FT_UINT8, BASE_HEX, NULL, 0,
 308                         "BLVC Function", HFILL }
 309                 },
 310                 { &hf_bvlc_length,
 311                         { "Length",           "bvlc.length",
 312                         FT_UINT16, BASE_DEC, NULL, 0,
 313                         "Length of BVLC", HFILL }
 314                 },
 315                 /* We should bitmask the result correctly when we have a
 316                  * packet to dissect */
 317                 { &hf_bvlc_result,
 318                         { "Result",           "bvlc.result",
 319                         FT_UINT16, BASE_HEX, NULL, 0xffff,
 320                         "Result Code", HFILL }
 321                 },
 322                 { &hf_bvlc_bdt_ip,
 323                         { "IP",           "bvlc.bdt_ip",
 324                         FT_IPv4, BASE_NONE, NULL, 0,
 325                         "BDT IP", HFILL }
 326                 },
 327                 { &hf_bvlc_bdt_port,
 328                         { "Port",           "bvlc.bdt_port",
 329                         FT_UINT16, BASE_DEC, NULL, 0,
 330                         "BDT Port", HFILL }
 331                 },
 332                 { &hf_bvlc_bdt_mask,
 333                         { "Mask",           "bvlc.bdt_mask",
 334                         FT_BYTES, BASE_HEX, NULL, 0,
 335                         "BDT Broadcast Distribution Mask", HFILL }
 336                 },
 337                 { &hf_bvlc_reg_ttl,
 338                         { "TTL",           "bvlc.reg_ttl",
 339                         FT_UINT16, BASE_DEC, NULL, 0,
 340                         "Foreign Device Time To Live", HFILL }
 341                 },
 342                 { &hf_bvlc_fdt_ip,
 343                         { "IP",           "bvlc.fdt_ip",
 344                         FT_IPv4, BASE_NONE, NULL, 0,
 345                         "FDT IP", HFILL }
 346                 },
 347                 { &hf_bvlc_fdt_port,
 348                         { "Port",           "bvlc.fdt_port",
 349                         FT_UINT16, BASE_DEC, NULL, 0,
 350                         "FDT Port", HFILL }
 351                 },
 352                 { &hf_bvlc_fdt_ttl,
 353                         { "TTL",           "bvlc.fdt_ttl",
 354                         FT_UINT16, BASE_DEC, NULL, 0,
 355                         "Foreign Device Time To Live", HFILL }
 356                 },
 357                 { &hf_bvlc_fdt_timeout,
 358                         { "Timeout",           "bvlc.fdt_timeout",
 359                         FT_UINT16, BASE_DEC, NULL, 0,
 360                         "Foreign Device Timeout (seconds)", HFILL }
 361                 },
 362                 { &hf_bvlc_fwd_ip,
 363                         { "IP",           "bvlc.fwd_ip",
 364                         FT_IPv4, BASE_NONE, NULL, 0,
 365                         "FWD IP", HFILL }
 366                 },
 367                 { &hf_bvlc_fwd_port,
 368                         { "Port",           "bvlc.fwd_port",
 369                         FT_UINT16, BASE_DEC, NULL, 0,
 370                         "FWD Port", HFILL }
 371                 },
 372         };
 373
 374         static gint *ett[] = {
 375                 &ett_bvlc,
 376                 &ett_bdt,
 377                 &ett_fdt,
 378         };
 379
 380         proto_bvlc = proto_register_protocol("BACnet Virtual Link Control",
 381             "BVLC", "bvlc");
 382
 383         proto_register_field_array(proto_bvlc, hf, array_length(hf));
 384         proto_register_subtree_array(ett, array_length(ett));
 385
 386         register_dissector("bvlc", dissect_bvlc, proto_bvlc);
 387
 388         bvlc_dissector_table = register_dissector_table("bvlc.function",
 389             "BVLC Function", FT_UINT8, BASE_HEX);
 390 }
 391
 392 void
 393 proto_reg_handoff_bvlc(void)
 394 {
 395         dissector_handle_t bvlc_handle;
 396
 397         bvlc_handle = find_dissector("bvlc");
 398         dissector_add("udp.port", 0xBAC0, bvlc_handle);
 399         data_handle = find_dissector("data");
 400 }
 401 /* Taken from add-135a (BACnet-IP-standard paper):
 402  *
 403  * The default UDP port for both directed messages and broadcasts shall
 404  * be X'BAC0' and all B/IP devices shall support it. In some cases,
 405  * e.g., a situation where it is desirable for two groups of BACnet devices
 406  * to coexist independently on the same IP subnet, the UDP port may be
 407  * configured locally to a different value without it being considered
 408  * a violation of this protocol.
 409  *
 410  * This dissector does not analyse UDP packets other than on port 0xBAC0.
 411  * If you changed your BACnet port locally, use the ethereal feature
 412  * "Decode As".
 413  */