epan/dissectors/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  * $Id$
   6  *
   7  * Wireshark - Network traffic analyzer
   8  * By Gerald Combs <gerald@wireshark.org>
   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 <epan/prefs.h>
  36 #include <epan/strutil.h>
  37
  38 #include <glib.h>
  39
  40 #include <epan/packet.h>
  41
  42 /* Taken from add-135a (BACnet-IP-standard paper):
  43  *
  44  * The default UDP port for both directed messages and broadcasts shall
  45  * be X'BAC0' and all B/IP devices shall support it. In some cases,
  46  * e.g., a situation where it is desirable for two groups of BACnet devices
  47  * to coexist independently on the same IP subnet, the UDP port may be
  48  * configured locally to a different value without it being considered
  49  * a violation of this protocol.
  50  */
  51 static guint additional_bvlc_udp_port = 0;
  52
  53 static int proto_bvlc = -1;
  54 static int hf_bvlc_type = -1;
  55 static int hf_bvlc_function = -1;
  56 static int hf_bvlc_length = -1;
  57 static int hf_bvlc_result = -1;
  58 static int hf_bvlc_bdt_ip = -1;
  59 static int hf_bvlc_bdt_mask = -1;
  60 static int hf_bvlc_bdt_port = -1;
  61 static int hf_bvlc_reg_ttl = -1;
  62 static int hf_bvlc_fdt_ip = -1;
  63 static int hf_bvlc_fdt_port = -1;
  64 static int hf_bvlc_fdt_ttl = -1;
  65 static int hf_bvlc_fdt_timeout = -1;
  66 static int hf_bvlc_fwd_ip = -1;
  67 static int hf_bvlc_fwd_port = -1;
  68
  69 static dissector_handle_t data_handle;
  70
  71 static dissector_table_t bvlc_dissector_table;
  72
  73 static const value_string bvlc_function_names[] = {
  74         { 0x00, "BVLC-Result", },
  75         { 0x01, "Write-Broadcast-Distribution-Table", },
  76         { 0x02, "Read-Broadcast-Distribution-Table", },
  77         { 0x03, "Read-Broadcast-Distribution-Table-Ack", },
  78         { 0x04, "Forwarded-NPDU", },
  79         { 0x05, "Register-Foreign-Device", },
  80         { 0x06, "Read-Foreign-Device-Table", },
  81         { 0x07, "Read-Foreign-Device-Table-Ack", },
  82         { 0x08, "Delete-Foreign-Device-Table-Entry", },
  83         { 0x09, "Distribute-Broadcast-To-Network", },
  84         { 0x0a, "Original-Unicast-NPDU", },
  85         { 0x0b, "Original-Broadcast-NPDU" },
  86         { 0,    NULL }
  87 };
  88
  89 static const value_string bvlc_result_names[] = {
  90         { 0x00, "Successful completion" },
  91         { 0x10, "Write-Broadcast-Distribution-Table NAK" },
  92         { 0x20, "Read-Broadcast-Distribution-Table NAK" },
  93         { 0x30, "Register-Foreign-Device NAK" },
  94         { 0x40, "Read-Foreign-Device-Table NAK" },
  95         { 0x50, "Delete-Foreign-Device-Table-Entry NAK" },
  96         { 0x60, "Distribute-Broadcast-To-Network NAK" },
  97         { 0,    NULL }
  98 };
  99
 100 static gint ett_bvlc = -1;
 101 static gint ett_bdt = -1;
 102 static gint ett_fdt = -1;
 103
 104 #define BACNET_IP_ANNEX_J       0x81
 105
 106 static const value_string bvlc_types[] = {
 107         { BACNET_IP_ANNEX_J,    "BACnet/IP (Annex J)" },
 108         { 0,                    NULL }
 109 };
 110
 111 static int
 112 dissect_bvlc(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 113 {
 114
 115         proto_item *ti;
 116         proto_item *ti_bdt;
 117         proto_item *ti_fdt;
 118         proto_tree *bvlc_tree;
 119         proto_tree *bdt_tree; /* Broadcast Distribution Table */
 120         proto_tree *fdt_tree; /* Foreign Device Table */
 121
 122         gint offset;
 123         guint8 bvlc_type;
 124         guint8 bvlc_function;
 125         guint16 bvlc_length;
 126         guint16 packet_length;
 127         guint npdu_length;
 128         guint length_remaining;
 129         guint16 bvlc_result;
 130         tvbuff_t *next_tvb;
 131
 132         offset = 0;
 133
 134         bvlc_type =  tvb_get_guint8(tvb, offset);
 135
 136         /*
 137          * Simple sanity check - make sure the type is one we know about.
 138          */
 139         if (match_strval(bvlc_type, bvlc_types) == NULL)
 140                 return 0;
 141
 142         if (check_col(pinfo->cinfo, COL_PROTOCOL))
 143                 col_set_str(pinfo->cinfo, COL_PROTOCOL, "BVLC");
 144
 145         if (check_col(pinfo->cinfo, COL_INFO))
 146                 col_set_str(pinfo->cinfo, COL_INFO, "BACnet Virtual Link Control");
 147
 148         bvlc_function = tvb_get_guint8(tvb, offset+1);
 149         packet_length = tvb_get_ntohs(tvb, offset+2);
 150         length_remaining = tvb_length_remaining(tvb, offset);
 151         if (bvlc_function > 0x08) {
 152                 /*  We have a constant header length of BVLC of 4 in every
 153                  *  BVLC-packet forewarding an NPDU. Beware: Changes in the
 154                  *  BACnet-IP-standard may break this.
 155                  *  At the moment, no functions above 0x0b
 156                  *  exist (Addendum 135a to ANSI/ASHRAE 135-1995 - BACnet)
 157                  */
 158                 bvlc_length = 4;
 159         } else if(bvlc_function == 0x04) {
 160                 /* 4 Bytes + 6 Bytes for B/IP Address of Originating Device */
 161                 bvlc_length = 10;
 162         } else {
 163                 /*  BVLC-packets with function below 0x09 contain
 164                  *  routing-level data (e.g. Broadcast Distribution)
 165                  *  but no NPDU for BACnet, so bvlc_length goes up to the end
 166                  *  of the captured frame.
 167                  */
 168                 bvlc_length = packet_length;
 169         }
 170
 171         if (tree) {
 172                 if (bvlc_length < 4) {
 173                         proto_tree_add_text(tree, tvb, 2, 2,
 174                                 "Bogus length: %d", bvlc_length);
 175                         return tvb_length(tvb); /* XXX - reject? */
 176                 }
 177                 ti = proto_tree_add_item(tree, proto_bvlc, tvb, 0,
 178                         bvlc_length, FALSE);
 179                 bvlc_tree = proto_item_add_subtree(ti, ett_bvlc);
 180                 proto_tree_add_uint(bvlc_tree, hf_bvlc_type, tvb, offset, 1,
 181                         bvlc_type);
 182                 offset ++;
 183                 proto_tree_add_uint(bvlc_tree, hf_bvlc_function, tvb,
 184                         offset, 1, bvlc_function);
 185                 offset ++;
 186                 if (length_remaining != packet_length)
 187                         proto_tree_add_uint_format_value(bvlc_tree, hf_bvlc_length, tvb, offset,
 188                                 2, bvlc_length,
 189                                 "%d of %d bytes (invalid length - expected %d bytes)",
 190                                 bvlc_length, packet_length, length_remaining);
 191                 else
 192                         proto_tree_add_uint_format_value(bvlc_tree, hf_bvlc_length, tvb, offset,
 193                                 2, bvlc_length, "%d of %d bytes BACnet packet length",
 194                                 bvlc_length, packet_length);
 195                 offset += 2;
 196                 switch (bvlc_function) {
 197                 case 0x00: /* BVLC-Result */
 198                         bvlc_result = tvb_get_ntohs(tvb, offset);
 199                         /* I dont know why the result code is encoded in 4 nibbles,
 200                          * but only using one: 0x00r0. Shifting left 4 bits.
 201                          */
 202                         /* We should bitmask the result correctly when we have a
 203                         * packet to dissect, see README.developer, 1.6.2, FID */
 204                         proto_tree_add_uint_format_value(bvlc_tree, hf_bvlc_result, tvb,
 205                                 offset, 2, bvlc_result,"0x%04x (%s)",
 206                                 bvlc_result, val_to_str(bvlc_result,
 207                                         bvlc_result_names, "Unknown"));
 208                         offset += 2;
 209                         break;
 210                 case 0x01: /* Write-Broadcast-Distribution-Table */
 211                 case 0x03: /* Read-Broadcast-Distribution-Table-Ack */
 212                         /* List of BDT Entries: N*10-octet */
 213                         ti_bdt = proto_tree_add_item(bvlc_tree, proto_bvlc, tvb,
 214                                 offset, bvlc_length-4, FALSE);
 215                         bdt_tree = proto_item_add_subtree(ti_bdt, ett_bdt);
 216                         /* List of BDT Entries: N*10-octet */
 217                         while ((bvlc_length - offset) > 9) {
 218                                 proto_tree_add_item(bdt_tree, hf_bvlc_bdt_ip,
 219                                         tvb, offset, 4, FALSE);
 220                                 offset += 4;
 221                                 proto_tree_add_item(bdt_tree, hf_bvlc_bdt_port,
 222                                         tvb, offset, 2, FALSE);
 223                                 offset += 2;
 224                                 proto_tree_add_item(bdt_tree,
 225                                         hf_bvlc_bdt_mask, tvb, offset, 4,
 226                                         FALSE);
 227                                 offset += 4;
 228                         }
 229                         /* We check this if we get a BDT-packet somewhere */
 230                         break;
 231                 case 0x02: /* Read-Broadcast-Distribution-Table */
 232                         /* nothing to do here */
 233                         break;
 234                 case 0x05: /* Register-Foreign-Device */
 235                         /* Time-to-Live 2-octets T, Time-to-Live T, in seconds */
 236                         proto_tree_add_item(bvlc_tree, hf_bvlc_reg_ttl,
 237                                 tvb, offset, 2, FALSE);
 238                         offset += 2;
 239                         break;
 240                 case 0x06: /* Read-Foreign-Device-Table */
 241                         /* nothing to do here */
 242                         break;
 243                 case 0x07: /* Read-Foreign-Device-Table-Ack */
 244                         /* List of FDT Entries: N*10-octet */
 245                         /* N indicates the number of entries in the FDT whose
 246                          * contents are being returned. Each returned entry
 247                          * consists of the 6-octet B/IP address of the registrant;
 248                          * the 2-octet Time-to-Live value supplied at the time of
 249                          * registration; and a 2-octet value representing the
 250                          * number of seconds remaining before the BBMD will purge
 251                          * the registrant's FDT entry if no re-registration occurs.
 252                          */
 253                         ti_fdt = proto_tree_add_item(bvlc_tree, proto_bvlc, tvb,
 254                                 offset, bvlc_length -4, FALSE);
 255                         fdt_tree = proto_item_add_subtree(ti_fdt, ett_fdt);
 256                         /* List of FDT Entries: N*10-octet */
 257                         while ((bvlc_length - offset) > 9) {
 258                                 proto_tree_add_item(fdt_tree, hf_bvlc_fdt_ip,
 259                                         tvb, offset, 4, FALSE);
 260                                 offset += 4;
 261                                 proto_tree_add_item(fdt_tree, hf_bvlc_fdt_port,
 262                                         tvb, offset, 2, FALSE);
 263                                 offset += 2;
 264                                 proto_tree_add_item(fdt_tree,
 265                                         hf_bvlc_fdt_ttl, tvb, offset, 2,
 266                                         FALSE);
 267                                 offset += 2;
 268                                 proto_tree_add_item(fdt_tree,
 269                                         hf_bvlc_fdt_timeout, tvb, offset, 2,
 270                                         FALSE);
 271                                 offset += 2;
 272                         }
 273                         /* We check this if we get a FDT-packet somewhere */
 274                         break;
 275                 case 0x08: /* Delete-Foreign-Device-Table-Entry */
 276                         /* FDT Entry:   6-octets */
 277                         proto_tree_add_item(bvlc_tree, hf_bvlc_fdt_ip,
 278                                 tvb, offset, 4, FALSE);
 279                         offset += 4;
 280                         proto_tree_add_item(bvlc_tree, hf_bvlc_fdt_port,
 281                                 tvb, offset, 2, FALSE);
 282                         offset += 2;
 283                         break;
 284                         /* We check this if we get a FDT-packet somewhere */
 285                 case 0x04:      /* Forwarded-NPDU
 286                                  * Why is this 0x04? It would have been a better
 287                                  * idea to append all forewarded NPDUs at the
 288                                  * end of the function table in the B/IP-standard!
 289                                  */
 290                         /* proto_tree_add_bytes_format(); */
 291                         proto_tree_add_item(bvlc_tree, hf_bvlc_fwd_ip,
 292                                 tvb, offset, 4, FALSE);
 293                         offset += 4;
 294                         proto_tree_add_item(bvlc_tree, hf_bvlc_fwd_port,
 295                                 tvb, offset, 2, FALSE);
 296                         offset += 2;
 297                 default:/* Distribute-Broadcast-To-Network
 298                          * Original-Unicast-NPDU
 299                          * Original-Broadcast-NPDU
 300                          * Going to the next dissector...
 301                          */
 302                         break;
 303                 }
 304
 305         }
 306 /* Ok, no routing information BVLC packet. Dissect as
 307  * BACnet NPDU
 308  */
 309         npdu_length = packet_length - bvlc_length;
 310         next_tvb = tvb_new_subset(tvb,bvlc_length,-1,npdu_length);
 311         /* Code from Guy Harris */
 312         if (!dissector_try_port(bvlc_dissector_table,
 313             bvlc_function, next_tvb, pinfo, tree)) {
 314                 /* Unknown function - dissect the paylod as data */
 315                 call_dissector(data_handle,next_tvb, pinfo, tree);
 316         }
 317         return tvb_length(tvb);
 318 }
 319
 320 void proto_reg_handoff_bvlc(void);
 321
 322 void
 323 proto_register_bvlc(void)
 324 {
 325         static hf_register_info hf[] = {
 326                 { &hf_bvlc_type,
 327                         { "Type",           "bvlc.type",
 328                         FT_UINT8, BASE_HEX, VALS(bvlc_types), 0,
 329                         "Type", HFILL }
 330                 },
 331                 { &hf_bvlc_function,
 332                         { "Function",           "bvlc.function",
 333                         FT_UINT8, BASE_HEX, VALS(bvlc_function_names), 0,
 334                         "BVLC Function", HFILL }
 335                 },
 336                 { &hf_bvlc_length,
 337                         { "BVLC-Length",        "bvlc.length",
 338                         FT_UINT16, BASE_DEC, NULL, 0,
 339                         "Length of BVLC", HFILL }
 340                 },
 341                 /* We should bitmask the result correctly when we have a
 342                  * packet to dissect */
 343                 { &hf_bvlc_result,
 344                         { "Result",           "bvlc.result",
 345                         FT_UINT16, BASE_HEX, NULL, 0xffff,
 346                         "Result Code", HFILL }
 347                 },
 348                 { &hf_bvlc_bdt_ip,
 349                         { "IP",           "bvlc.bdt_ip",
 350                         FT_IPv4, BASE_NONE, NULL, 0,
 351                         "BDT IP", HFILL }
 352                 },
 353                 { &hf_bvlc_bdt_port,
 354                         { "Port",           "bvlc.bdt_port",
 355                         FT_UINT16, BASE_DEC, NULL, 0,
 356                         "BDT Port", HFILL }
 357                 },
 358                 { &hf_bvlc_bdt_mask,
 359                         { "Mask",           "bvlc.bdt_mask",
 360                         FT_BYTES, BASE_HEX, NULL, 0,
 361                         "BDT Broadcast Distribution Mask", HFILL }
 362                 },
 363                 { &hf_bvlc_reg_ttl,
 364                         { "TTL",           "bvlc.reg_ttl",
 365                         FT_UINT16, BASE_DEC, NULL, 0,
 366                         "Foreign Device Time To Live", HFILL }
 367                 },
 368                 { &hf_bvlc_fdt_ip,
 369                         { "IP",           "bvlc.fdt_ip",
 370                         FT_IPv4, BASE_NONE, NULL, 0,
 371                         "FDT IP", HFILL }
 372                 },
 373                 { &hf_bvlc_fdt_port,
 374                         { "Port",           "bvlc.fdt_port",
 375                         FT_UINT16, BASE_DEC, NULL, 0,
 376                         "FDT Port", HFILL }
 377                 },
 378                 { &hf_bvlc_fdt_ttl,
 379                         { "TTL",           "bvlc.fdt_ttl",
 380                         FT_UINT16, BASE_DEC, NULL, 0,
 381                         "Foreign Device Time To Live", HFILL }
 382                 },
 383                 { &hf_bvlc_fdt_timeout,
 384                         { "Timeout",           "bvlc.fdt_timeout",
 385                         FT_UINT16, BASE_DEC, NULL, 0,
 386                         "Foreign Device Timeout (seconds)", HFILL }
 387                 },
 388                 { &hf_bvlc_fwd_ip,
 389                         { "IP",           "bvlc.fwd_ip",
 390                         FT_IPv4, BASE_NONE, NULL, 0,
 391                         "FWD IP", HFILL }
 392                 },
 393                 { &hf_bvlc_fwd_port,
 394                         { "Port",           "bvlc.fwd_port",
 395                         FT_UINT16, BASE_DEC, NULL, 0,
 396                         "FWD Port", HFILL }
 397                 },
 398         };
 399
 400         static gint *ett[] = {
 401                 &ett_bvlc,
 402                 &ett_bdt,
 403                 &ett_fdt,
 404         };
 405
 406         module_t *bvlc_module;
 407
 408         proto_bvlc = proto_register_protocol("BACnet Virtual Link Control",
 409             "BVLC", "bvlc");
 410
 411         proto_register_field_array(proto_bvlc, hf, array_length(hf));
 412         proto_register_subtree_array(ett, array_length(ett));
 413
 414         bvlc_module = prefs_register_protocol(proto_bvlc, proto_reg_handoff_bvlc);
 415         prefs_register_uint_preference(bvlc_module, "additional_udp_port",
 416                                         "Additional UDP port", "Set an additional UDP port, "
 417                                         "besides the standard X'BAC0' (47808) port.",
 418                                         10, &additional_bvlc_udp_port);
 419
 420         new_register_dissector("bvlc", dissect_bvlc, proto_bvlc);
 421
 422         bvlc_dissector_table = register_dissector_table("bvlc.function",
 423             "BVLC Function", FT_UINT8, BASE_HEX);
 424 }
 425
 426 void
 427 proto_reg_handoff_bvlc(void)
 428 {
 429         static int bvlc_initialized = FALSE;
 430         static dissector_handle_t bvlc_handle;
 431         static guint bvlc_udp_port;
 432
 433         if (!bvlc_initialized)
 434         {
 435                 bvlc_handle = find_dissector("bvlc");
 436                 dissector_add("udp.port", 0xBAC0, bvlc_handle);
 437                 bvlc_initialized = TRUE;
 438         }
 439         else
 440         {
 441                 dissector_delete("udp.port", bvlc_udp_port, bvlc_handle);
 442         }
 443
 444         bvlc_udp_port = additional_bvlc_udp_port;
 445         dissector_add("udp.port", bvlc_udp_port, bvlc_handle);
 446
 447         data_handle = find_dissector("data");
 448 }