epan/dissectors/packet-gsm_cbch.c

   1 /* packet-gsm_cbch.c
   2  * Routines for GSM CBCH dissection - A.K.A. 3GPP 44.012 (GSM 04.12)
   3  *
   4  * Copyright 2011, Mike Morrin <mike.morrin [AT] ipaccess.com>
   5  *
   6  * $Id$
   7  *
   8  * Wireshark - Network traffic analyzer
   9  * By Gerald Combs <gerald@wireshark.org>
  10  * Copyright 1998 Gerald Combs
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version 2
  15  * of the License, or (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  25  */
  26
  27 #include "config.h"
  28
  29 #include <epan/packet.h>
  30 #include <epan/reassemble.h>
  31 #include "packet-cell_broadcast.h"
  32
  33 #define CBCH_FRAGMENT_SIZE 22
  34
  35 const value_string block_type_lpd_strings[] = {
  36     { 0x00, "NOT Cell Broadcast"},
  37     { 0x01, "Cell Broadcast"},
  38     { 0x02, "NOT Cell Broadcast"},
  39     { 0x03, "NOT Cell Broadcast"},
  40     {    0, NULL}
  41 };
  42
  43 const value_string block_type_seq_num_values[] = {
  44     { 0x00, "First Block"},
  45     { 0x01, "Second Block"},
  46     { 0x02, "Third Block"},
  47     { 0x03, "Fourth Block"},
  48     { 0x08, "First Schedule Block"},
  49     { 0xFF, "Null message"},
  50     {    0, NULL}
  51 };
  52
  53 const value_string sched_type_values[] = {
  54     { 0x00, "messages formatted as specified in subclause 3.5 of 3GPP 44.012"},
  55     { 0xFF, "Unknown schedule message format"},
  56     {    0, NULL}
  57 };
  58
  59 /* Initialize the protocol and registered fields */
  60 static int proto_cbch = -1;
  61
  62 static int hf_gsm_cbch_spare_bit = -1;
  63 static int hf_gsm_cbch_lpd = -1;
  64 static int hf_gsm_cbch_lb = -1;
  65 static int hf_gsm_cbch_seq_num = -1;
  66 static int hf_gsm_cbch_sched_type = -1;
  67 static int hf_gsm_cbch_sched_begin_slot = -1;
  68 static int hf_gsm_cbch_sched_spare = -1;
  69 static int hf_gsm_cbch_sched_end_slot = -1;
  70 /* static int hf_gsm_cbch_sched_msg_id = -1; */
  71
  72 /* These fields are used when reassembling cbch fragments
  73  */
  74 static int hf_cbch_fragments = -1;
  75 static int hf_cbch_fragment = -1;
  76 static int hf_cbch_fragment_overlap = -1;
  77 static int hf_cbch_fragment_overlap_conflict = -1;
  78 static int hf_cbch_fragment_multiple_tails = -1;
  79 static int hf_cbch_fragment_too_long_fragment = -1;
  80 static int hf_cbch_fragment_error = -1;
  81 static int hf_cbch_fragment_count = -1;
  82 static int hf_cbch_reassembled_in = -1;
  83 static int hf_cbch_reassembled_length = -1;
  84
  85 /* Initialize the subtree pointers */
  86 static gint ett_cbch_msg = -1;
  87 static gint ett_schedule_msg = -1;
  88 static gint ett_schedule_new_msg = -1;
  89 static gint ett_cbch_fragment = -1;
  90 static gint ett_cbch_fragments = -1;
  91
  92 static dissector_handle_t data_handle;
  93 static dissector_handle_t cbs_handle;
  94
  95 /* reassembly of CHCH blocks */
  96 static reassembly_table cbch_block_reassembly_table;
  97
  98 /* Structure needed for the fragmentation routines in reassemble.c
  99  */
 100 static const fragment_items cbch_frag_items = {
 101     &ett_cbch_fragment,
 102     &ett_cbch_fragments,
 103     &hf_cbch_fragments,
 104     &hf_cbch_fragment,
 105     &hf_cbch_fragment_overlap,
 106     &hf_cbch_fragment_overlap_conflict,
 107     &hf_cbch_fragment_multiple_tails,
 108     &hf_cbch_fragment_too_long_fragment,
 109     &hf_cbch_fragment_error,
 110     &hf_cbch_fragment_count,
 111     &hf_cbch_reassembled_in,
 112     &hf_cbch_reassembled_length,
 113     /* Reassembled data field */
 114     NULL,
 115     "blocks"
 116 };
 117
 118 static void
 119 cbch_defragment_init(void)
 120 {
 121     reassembly_table_init(&cbch_block_reassembly_table,
 122                           &addresses_reassembly_table_functions);
 123 }
 124
 125 static void
 126 dissect_schedule_message(tvbuff_t *tvb, packet_info *pinfo, proto_tree *top_tree)
 127 {
 128     guint       len, offset     = 0;
 129     guint8      octet1, i, j, k = 0;
 130     guint8      sched_begin, sched_end, new_slots[48];
 131     gboolean    valid_message   = TRUE;
 132     guint16     other_slots[48];
 133     proto_item *item            = NULL, *schedule_item = NULL;
 134     proto_tree *sched_tree      = NULL, *sched_subtree = NULL;
 135
 136     len = tvb_length(tvb);
 137
 138     col_append_str(pinfo->cinfo, COL_INFO, " CBCH Schedule Message ");
 139
 140     schedule_item = proto_tree_add_protocol_format(top_tree, proto_cbch, tvb, 0, len,
 141                                                    "GSM CBCH Schedule Message");
 142
 143     sched_tree = proto_item_add_subtree(schedule_item, ett_schedule_msg);
 144
 145     proto_tree_add_item(sched_tree, hf_gsm_cbch_sched_type, tvb, offset, 1, ENC_BIG_ENDIAN);
 146     octet1 = tvb_get_guint8(tvb, offset);
 147     if (0 == (octet1 & 0xC0))
 148     {
 149         sched_begin = octet1 & 0x3F;
 150         proto_tree_add_item(sched_tree, hf_gsm_cbch_sched_begin_slot, tvb, offset++, 1, ENC_BIG_ENDIAN);
 151         if (1 == sched_begin)
 152         {
 153             proto_tree_add_text(sched_tree, tvb, offset - 1, 1, "(apparently) Scheduled Scheduling Message");
 154         }
 155         else if ((2 <= sched_begin) && (48 >= sched_begin))
 156         {
 157             proto_tree_add_text(sched_tree, tvb, offset - 1, 1, "(apparently) Unscheduled Scheduling Message");
 158         }
 159         else
 160         {
 161             proto_tree_add_text(sched_tree, tvb, offset - 1, 1, "Begin Slot Number out of range: ignoring message");
 162             valid_message = FALSE;
 163         }
 164         proto_tree_add_item(sched_tree, hf_gsm_cbch_sched_spare, tvb, offset, 1, ENC_BIG_ENDIAN);
 165         sched_end = tvb_get_guint8(tvb, offset);
 166         proto_tree_add_item(sched_tree, hf_gsm_cbch_sched_end_slot, tvb, offset++, 1, ENC_BIG_ENDIAN);
 167         if (sched_end < sched_begin)
 168         {
 169             proto_tree_add_text(sched_tree, tvb, offset - 1, 1, "End Slot Number less than Begin Slot Number: ignoring message");
 170             valid_message = FALSE;
 171         }
 172
 173         if (valid_message)
 174         {
 175             /* build an array of new messages */
 176             memset(&new_slots,   0xFF, sizeof(new_slots));
 177             memset(&other_slots, 0xFF, sizeof(other_slots));
 178
 179             /* iterate over the octets */
 180             for (i=0; i<6; i++)
 181             {
 182                 octet1 = tvb_get_guint8(tvb, offset++);
 183
 184                 /* iterate over the bits */
 185                 for (j=0; j<8; j++)
 186                 {
 187                     if (octet1 & (0x80>>j))
 188                     {
 189                         new_slots[k++] = (i<<3) + j + 1;
 190                     }
 191                 }
 192             }
 193             /* print the array of new messages */
 194             item = proto_tree_add_text(sched_tree, tvb, offset-6, 6, "This schedule contains %d slots with new messages", k);
 195             sched_subtree = proto_item_add_subtree(item, ett_schedule_new_msg);
 196             for (i=0; i<k; i++)
 197             {
 198                 DISSECTOR_ASSERT(new_slots[i] < 48);
 199                 octet1 = tvb_get_guint8(tvb, offset);
 200                 if ((octet1 & 0x80) == 0x80)
 201                 {
 202                     /* MDT 1 */
 203                     guint8 octet2;
 204                     guint16 msg_id;
 205
 206                     octet2 = tvb_get_guint8(tvb, offset + 1);
 207                     msg_id = ((octet1 &0x7F) << 8) + octet2;
 208                     proto_tree_add_text(sched_subtree, tvb, offset, 2,
 209                                         "Slot: %d, Message ID: %d, First transmission of an SMSCB within the Schedule Period",
 210                                         new_slots[i], msg_id);
 211                     offset +=2;
 212                     other_slots[new_slots[i] - 1] = msg_id;
 213                 }
 214                 else if ((octet1 & 0xC0) == 0)
 215                 {
 216                     /* MDT 00 */
 217                     if (octet1 < new_slots[i])
 218                     {
 219                         proto_tree_add_text(sched_subtree, tvb, offset++, 1,
 220                                             "Slot: %d, Message ID: %d, Repeat of Slot %d",
 221                                             new_slots[i], other_slots[octet1 - 1], octet1);
 222                         other_slots[new_slots[i] - 1] = other_slots[octet1 - 1];
 223                     }
 224                     else
 225                     {
 226                         proto_tree_add_text(sched_subtree, tvb, offset++, 1,
 227                                             "Slot: %d, Apparent forward reference to slot %d",
 228                                             new_slots[i], octet1);
 229                     }
 230                 }
 231                 else if (octet1 == 0x40)
 232                 {
 233                     /* MDT 010000000 */
 234                     proto_tree_add_text(sched_subtree, tvb, offset++, 1, "Slot: %d Free Message Slot, optional reading", new_slots[k]);
 235                     other_slots[new_slots[i] - 1] = 0xFFFE;
 236                 }
 237                 else if (octet1 == 0x41)
 238                 {
 239                     /* MDT 010000001 */
 240                     proto_tree_add_text(sched_subtree, tvb, offset++, 1, "Slot: %d Free Message Slot, reading advised", new_slots[k]);
 241                     other_slots[new_slots[i] - 1] = 0xFFFE;
 242                 }
 243                 else
 244                 {
 245                     /* reserved MDT */
 246                     proto_tree_add_text(sched_subtree, tvb, offset, 1, "Slot: %d reserved MDT: %x", new_slots[k], octet1);
 247                     other_slots[new_slots[i] - 1] = 0xFFFE;
 248                 }
 249             }
 250             proto_item_set_end(item, tvb, offset);
 251
 252             /* print schedule of other messages */
 253             item = proto_tree_add_text(sched_tree, tvb, offset, 0, "Other message slots in this schedule");
 254             sched_subtree = proto_item_add_subtree(item, ett_schedule_new_msg);
 255             for (k=0; offset < len; j++)
 256             {
 257                 while ((other_slots[k]!=0xFFFF) && (k<sched_end))
 258                 {
 259                     k++;
 260                 }
 261                 if (k >= sched_end)
 262                     break;
 263
 264                 octet1 = tvb_get_guint8(tvb, offset);
 265                 if ((octet1 & 0x80) == 0x80)
 266                 {
 267                     if ((offset+1)<len)
 268                     {
 269                         /* MDT 1 */
 270                         guint8  octet2;
 271                         guint16 msg_id;
 272
 273                         octet2 = tvb_get_guint8(tvb, offset + 1);
 274                         msg_id = ((octet1 &0x7F) << 8) + octet2;
 275                         other_slots[k] = msg_id;
 276                         proto_tree_add_text(sched_subtree, tvb, offset, 2,
 277                                             "Slot: %d, Message: %d, First transmission of an SMSCB within the Schedule Period",
 278                                             ++k, msg_id);
 279                         offset +=2;
 280                     }
 281                     else
 282                     {
 283                         /* I'm not sure what's supposed to be dissected in this
 284                          * case. Perhaps just an expert info is appropriate?
 285                          * Regardless, we need to increment k to prevent an
 286                          * infinite loop, see
 287                          * https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=8730
 288                          */
 289                         ++k;
 290                     }
 291                 }
 292                 else if ((octet1 & 0xC0) == 0)
 293                 {
 294                     /* MDT 00 */
 295                     if (octet1 < k)
 296                     {
 297                         other_slots[k] = other_slots[octet1 - 1];
 298                         proto_tree_add_text(sched_subtree, tvb, offset++, 1,
 299                                             "Slot: %d, Message ID: %d, Repeat of Slot %d",
 300                                             ++k, other_slots[octet1 - 1], octet1);
 301                     }
 302                     else
 303                     {
 304                         proto_tree_add_text(sched_subtree, tvb, offset++, 1,
 305                                             "Slot: %d, Apparent forward reference to slot %d",
 306                                             ++k, octet1);
 307                     }
 308                 }
 309                 else if (octet1 == 0x40)
 310                 {
 311                     /* MDT 010000000 */
 312                     proto_tree_add_text(sched_subtree, tvb, offset++, 1, "Slot: %d Free Message Slot, optional reading", ++k);
 313                 }
 314                 else if (octet1 == 0x41)
 315                 {
 316                     /* MDT 010000001 */
 317                     proto_tree_add_text(sched_subtree, tvb, offset++, 1, "Slot: %d Free Message Slot, reading advised", ++k);
 318                 }
 319                 else
 320                 {
 321                     /* reserved MDT */
 322                     proto_tree_add_text(sched_subtree, tvb, offset, 1, "Slot: %d reserved MDT: %x", ++k, octet1);
 323                 }
 324             }
 325             proto_item_set_end(item, tvb, offset);
 326             proto_tree_add_text(sched_tree, tvb, offset, -1, "Padding");
 327         }
 328     }
 329 }
 330
 331 static void
 332 dissect_cbch(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 333 {
 334     fragment_head *frag_data = NULL;
 335     guint8         octet, lb, lpd, seq_num;
 336     guint32        offset;
 337     guint32        len;
 338     proto_item    *cbch_item = NULL;
 339     proto_tree    *cbch_tree = NULL;
 340     tvbuff_t      *reass_tvb = NULL, *msg_tvb = NULL;
 341
 342     len    = tvb_length(tvb);
 343     offset = 0;
 344     octet  = tvb_get_guint8(tvb, offset);
 345
 346     /*
 347      * create the protocol tree
 348      */
 349     cbch_item = proto_tree_add_protocol_format(tree, proto_cbch, tvb, 0, len,
 350                                                "GSM CBCH - Block (0x%02x)", octet&3);
 351
 352     col_append_str(pinfo->cinfo, COL_PROTOCOL, " CBCH");
 353
 354     cbch_tree = proto_item_add_subtree(cbch_item, ett_cbch_msg);
 355
 356     proto_tree_add_text(cbch_tree, tvb, offset, 1, "CBCH Block");
 357
 358     proto_tree_add_uint(cbch_tree, hf_gsm_cbch_spare_bit, tvb, offset, 1, octet);
 359     proto_tree_add_uint(cbch_tree, hf_gsm_cbch_lpd,       tvb, offset, 1, octet);
 360     proto_tree_add_uint(cbch_tree, hf_gsm_cbch_lb,        tvb, offset, 1, octet);
 361     proto_tree_add_uint(cbch_tree, hf_gsm_cbch_seq_num,   tvb, offset, 1, octet);
 362     seq_num =  octet & 0x0F;
 363     lpd     = (octet & 0x60) >> 5;
 364     lb      = (octet & 0x10) >> 4;
 365
 366     if (lpd == 1)
 367     {
 368         switch (seq_num)
 369         {
 370         case 0x00:
 371         case 0x08:
 372             pinfo->fragmented = TRUE;
 373             /* we should have a unique ID for the reassembled page, but we don't really have anything from the protocol...
 374                The GSM frame number div 4 might be used for this, but it has not been passed to this layer and does not
 375                exist at all if the message is being passed over the RSL interface.
 376                So we just use 0... */
 377
 378             /* after reassembly we will need to know if this is a scheduling message,
 379                this information is carried in the initial sequence number, not the payload,
 380                so we prepend the reassembly with the octet containing the initial sequence number
 381                to allow later dissection of the payload */
 382             frag_data = fragment_add_seq_check(&cbch_block_reassembly_table,
 383                                                tvb, offset, pinfo, 0, NULL,
 384                                                seq_num & 0x03, CBCH_FRAGMENT_SIZE + 1, !lb);
 385             reass_tvb = process_reassembled_data(tvb, offset, pinfo, "Reassembled CBCH message",
 386                                                  frag_data, &cbch_frag_items, NULL, cbch_tree);
 387             break;
 388
 389         case 0x01:
 390         case 0x02:
 391         case 0x03:
 392             pinfo->fragmented = TRUE;
 393             offset++; /* step to beginning of payload */
 394             frag_data = fragment_add_seq_check(&cbch_block_reassembly_table,
 395                                                tvb, offset, pinfo, 0, NULL,
 396                                                seq_num, CBCH_FRAGMENT_SIZE, !lb);
 397             reass_tvb = process_reassembled_data(tvb, offset, pinfo, "Reassembled CBCH message",
 398                                                  frag_data, &cbch_frag_items, NULL, cbch_tree);
 399             break;
 400
 401         case 0x0F:
 402             proto_tree_add_text(cbch_tree, tvb, offset, 1, "NULL message");
 403             call_dissector(data_handle, tvb, pinfo, cbch_tree);
 404             break;
 405
 406         default:
 407             proto_tree_add_text(cbch_tree, tvb, offset, 1, "reserved Sequence Number");
 408             call_dissector(data_handle, tvb, pinfo, cbch_tree);
 409             break;
 410         }
 411         if (reass_tvb)
 412         {
 413             /* Reassembled */
 414
 415             /* the tvb contains the reassmbled message prepended with the sequence number octet from the first block
 416                We use this to determine whether this is a normal message or a scheduling message */
 417             offset = 0;
 418
 419             octet = tvb_get_guint8(reass_tvb, offset++);
 420             msg_tvb = tvb_new_subset_remaining(reass_tvb, offset);
 421
 422             if (octet & 0x08)
 423             {
 424                 dissect_schedule_message(msg_tvb, pinfo, tree);
 425             }
 426             else
 427             {
 428                 call_dissector(cbs_handle, msg_tvb, pinfo, tree);
 429             }
 430         }
 431     }
 432     else
 433     {
 434         proto_tree_add_text(cbch_tree, tvb, offset, 1, "invalid Link Protocol Discriminator");
 435         call_dissector(data_handle, tvb, pinfo, cbch_tree);
 436     }
 437 }
 438
 439 /* Register the protocol with Wireshark */
 440 void
 441 proto_register_gsm_cbch(void)
 442 {
 443     /* Setup list of header fields */
 444     static hf_register_info hf_smscb[] =
 445         {
 446             { &hf_gsm_cbch_spare_bit,
 447               { "GSM CBCH spare bit",  "gsm_cbch.block_type.spare",
 448                 FT_UINT8, BASE_HEX, NULL, 0x80,
 449                 NULL, HFILL}
 450             },
 451             { &hf_gsm_cbch_lpd,
 452               { "GSM CBCH Link Protocol Discriminator",  "gsm_cbch.block_type.lpd",
 453                 FT_UINT8, BASE_DEC, VALS(block_type_lpd_strings), 0x60,
 454                 NULL, HFILL}
 455             },
 456             { &hf_gsm_cbch_lb,
 457               { "GSM CBCH Last Block", "gsm_cbch.block_type.lb",
 458                 FT_UINT8, BASE_DEC, NULL, 0x10,
 459                 NULL, HFILL}
 460             },
 461             { &hf_gsm_cbch_seq_num,
 462               { "GSM CBCH Sequence Number",  "gsm_cbch.block_type.seq_num",
 463                 FT_UINT8, BASE_DEC, VALS(block_type_seq_num_values), 0x0F,
 464                 NULL, HFILL}
 465             },
 466             { &hf_gsm_cbch_sched_type,
 467               { "GSM CBCH Schedule Type", "gsm_cbch.sched_type",
 468                 FT_UINT8, BASE_DEC, VALS(sched_type_values), 0xC0,
 469                 NULL, HFILL}
 470             },
 471             { &hf_gsm_cbch_sched_begin_slot,
 472               { "GSM CBCH Schedule Begin slot", "gsm_cbch.schedule_begin",
 473                 FT_UINT8, BASE_DEC, NULL, 0x3F,
 474                 NULL, HFILL}
 475             },
 476             { &hf_gsm_cbch_sched_spare,
 477               { "GSM CBCH Schedule Spare Bits", "gsm_cbch.sched_spare",
 478                 FT_UINT8, BASE_DEC, NULL, 0xC0,
 479                 NULL, HFILL}
 480             },
 481             { &hf_gsm_cbch_sched_end_slot,
 482               { "GSM CBCH Schedule End Slot",   "gsm_cbch.sched_end",
 483                 FT_UINT8, BASE_DEC, NULL, 0x3F,
 484                 NULL, HFILL}
 485             },
 486 #if 0
 487             { &hf_gsm_cbch_sched_msg_id,
 488               { "GSM CBCH Schedule Message ID", "gsm_cbch.sched_msg_id",
 489                 FT_UINT16, BASE_DEC, NULL, 0x0,
 490                 NULL, HFILL}
 491             },
 492 #endif
 493             /* Fragment fields
 494              */
 495             { &hf_cbch_fragment_overlap,
 496               {   "Fragment overlap",
 497                   "gsm_cbch.fragment.overlap",
 498                   FT_BOOLEAN, BASE_NONE, NULL, 0x0,
 499                   "Fragment overlaps with other fragments", HFILL
 500               }
 501             },
 502             { &hf_cbch_fragment_overlap_conflict,
 503               {   "Conflicting data in fragment overlap",
 504                   "gsm_cbch.fragment.overlap.conflict",
 505                   FT_BOOLEAN, BASE_NONE, NULL, 0x0,
 506                   "Overlapping fragments contained conflicting data", HFILL
 507               }
 508             },
 509             { &hf_cbch_fragment_multiple_tails,
 510               {   "Multiple tail fragments found",
 511                   "gsm_cbch.fragment.multipletails",
 512                   FT_BOOLEAN, BASE_NONE, NULL, 0x0,
 513                   "Several tails were found when defragmenting the packet", HFILL
 514               }
 515             },
 516             { &hf_cbch_fragment_too_long_fragment,
 517               {   "Fragment too long",
 518                   "gsm_cbch.fragment.toolongfragment",
 519                   FT_BOOLEAN, BASE_NONE, NULL, 0x0,
 520                   "Fragment contained data past end of packet", HFILL
 521               }
 522             },
 523             { &hf_cbch_fragment_error,
 524               {   "Defragmentation error",
 525                   "gsm_cbch.fragment.error",
 526                   FT_FRAMENUM, BASE_NONE, NULL, 0x0,
 527                   "Defragmentation error due to illegal fragments", HFILL
 528               }
 529             },
 530             { &hf_cbch_fragment_count,
 531               {   "Fragmentation count",
 532                   "gsm_cbch.fragment.count",
 533                   FT_UINT32, BASE_DEC, NULL, 0x0,
 534                   "Count of CBCH Fragments", HFILL
 535               }
 536             },
 537             { &hf_cbch_reassembled_in,
 538               {   "Reassembled in",
 539                   "gsm_cbch.reassembled.in",
 540                   FT_FRAMENUM, BASE_NONE, NULL, 0x0,
 541                   "CBCH fragments are reassembled in the given packet", HFILL
 542               }
 543             },
 544             { &hf_cbch_reassembled_length,
 545               {   "Reassembled message length is one less than indicated here",
 546                   "gsm_cbch.reassembled.length",
 547                   FT_UINT32, BASE_DEC, NULL, 0x0,
 548                   "The total length of the reassembled message", HFILL
 549               }
 550             },
 551             { &hf_cbch_fragment,
 552               {   "CBCH Fragment",
 553                   "gsm_cbch.fragment",
 554                   FT_FRAMENUM, BASE_NONE, NULL, 0x0,
 555                   NULL, HFILL
 556               }
 557             },
 558             { &hf_cbch_fragments,
 559               {   "CBCH Fragments",
 560                   "gsm_cbch.fragments",
 561                   FT_NONE, BASE_NONE, NULL, 0x0,
 562                   NULL, HFILL
 563               }
 564             }
 565         };
 566
 567 /* Setup protocol subtree array */
 568     static gint *ett[] = {
 569         &ett_cbch_msg,
 570         &ett_schedule_msg,
 571         &ett_schedule_new_msg,
 572         &ett_cbch_fragment,
 573         &ett_cbch_fragments,
 574     };
 575
 576     /* Register the protocol name and description */
 577     proto_cbch = proto_register_protocol("GSM Cell Broadcast Channel", "GSM CBCH", "gsm_cbch");
 578     proto_register_field_array(proto_cbch, hf_smscb, array_length(hf_smscb));
 579
 580     /* subdissector code */
 581     register_dissector("gsm_cbch", dissect_cbch, proto_cbch);
 582     register_init_routine(cbch_defragment_init);
 583
 584     /* subtree array */
 585     proto_register_subtree_array(ett, array_length(ett));
 586 }
 587
 588 void
 589 proto_reg_handoff_gsm_cbch(void)
 590 {
 591     data_handle = find_dissector("data");
 592     cbs_handle  = find_dissector("gsm_cbs");
 593 }