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     guint8      octet1, i, j, k = 0;
 129     guint8      len, sched_begin, sched_end, new_slots[48];
 130     guint8      offset          = 0;
 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                 }
 282                 else if ((octet1 & 0xC0) == 0)
 283                 {
 284                     /* MDT 00 */
 285                     if (octet1 < k)
 286                     {
 287                         other_slots[k] = other_slots[octet1 - 1];
 288                         proto_tree_add_text(sched_subtree, tvb, offset++, 1,
 289                                             "Slot: %d, Message ID: %d, Repeat of Slot %d",
 290                                             ++k, other_slots[octet1 - 1], octet1);
 291                     }
 292                     else
 293                     {
 294                         proto_tree_add_text(sched_subtree, tvb, offset++, 1,
 295                                             "Slot: %d, Apparent forward reference to slot %d",
 296                                             ++k, octet1);
 297                     }
 298                 }
 299                 else if (octet1 == 0x40)
 300                 {
 301                     /* MDT 010000000 */
 302                     proto_tree_add_text(sched_subtree, tvb, offset++, 1, "Slot: %d Free Message Slot, optional reading", ++k);
 303                 }
 304                 else if (octet1 == 0x41)
 305                 {
 306                     /* MDT 010000001 */
 307                     proto_tree_add_text(sched_subtree, tvb, offset++, 1, "Slot: %d Free Message Slot, reading advised", ++k);
 308                 }
 309                 else
 310                 {
 311                     /* reserved MDT */
 312                     proto_tree_add_text(sched_subtree, tvb, offset, 1, "Slot: %d reserved MDT: %x", ++k, octet1);
 313                 }
 314             }
 315             proto_item_set_end(item, tvb, offset);
 316             proto_tree_add_text(sched_tree, tvb, offset, -1, "Padding");
 317         }
 318     }
 319 }
 320
 321 static void
 322 dissect_cbch(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 323 {
 324     fragment_data *frag_data = NULL;
 325     guint8         octet, lb, lpd, seq_num;
 326     guint32        offset;
 327     guint32        len;
 328     proto_item    *cbch_item = NULL;
 329     proto_tree    *cbch_tree = NULL;
 330     tvbuff_t      *reass_tvb = NULL, *msg_tvb = NULL;
 331
 332     len    = tvb_length(tvb);
 333     offset = 0;
 334     octet  = tvb_get_guint8(tvb, offset);
 335
 336     /*
 337      * create the protocol tree
 338      */
 339     cbch_item = proto_tree_add_protocol_format(tree, proto_cbch, tvb, 0, len,
 340                                                "GSM CBCH - Block (0x%02x)", octet&3);
 341
 342     col_append_str(pinfo->cinfo, COL_PROTOCOL, " CBCH");
 343
 344     cbch_tree = proto_item_add_subtree(cbch_item, ett_cbch_msg);
 345
 346     proto_tree_add_text(cbch_tree, tvb, offset, 1, "CBCH Block");
 347
 348     proto_tree_add_uint(cbch_tree, hf_gsm_cbch_spare_bit, tvb, offset, 1, octet);
 349     proto_tree_add_uint(cbch_tree, hf_gsm_cbch_lpd,       tvb, offset, 1, octet);
 350     proto_tree_add_uint(cbch_tree, hf_gsm_cbch_lb,        tvb, offset, 1, octet);
 351     proto_tree_add_uint(cbch_tree, hf_gsm_cbch_seq_num,   tvb, offset, 1, octet);
 352     seq_num =  octet & 0x0F;
 353     lpd     = (octet & 0x60) >> 5;
 354     lb      = (octet & 0x10) >> 4;
 355
 356     if (lpd == 1)
 357     {
 358         switch (seq_num)
 359         {
 360         case 0x00:
 361         case 0x08:
 362             pinfo->fragmented = TRUE;
 363             /* we should have a unique ID for the reassembled page, but we don't really have anything from the protocol...
 364                The GSM frame number div 4 might be used for this, but it has not been passed to this layer and does not
 365                exist at all if the message is being passed over the RSL interface.
 366                So we just use 0... */
 367
 368             /* after reassembly we will need to know if this is a scheduling message,
 369                this information is carried in the initial sequence number, not the payload,
 370                so we prepend the reassembly with the octet containing the initial sequence number
 371                to allow later dissection of the payload */
 372             frag_data = fragment_add_seq_check(&cbch_block_reassembly_table,
 373                                                tvb, offset, pinfo, 0, NULL,
 374                                                seq_num & 0x03, CBCH_FRAGMENT_SIZE + 1, !lb);
 375             reass_tvb = process_reassembled_data(tvb, offset, pinfo, "Reassembled CBCH message",
 376                                                  frag_data, &cbch_frag_items, NULL, cbch_tree);
 377             break;
 378
 379         case 0x01:
 380         case 0x02:
 381         case 0x03:
 382             pinfo->fragmented = TRUE;
 383             offset++; /* step to beginning of payload */
 384             frag_data = fragment_add_seq_check(&cbch_block_reassembly_table,
 385                                                tvb, offset, pinfo, 0, NULL,
 386                                                seq_num, CBCH_FRAGMENT_SIZE, !lb);
 387             reass_tvb = process_reassembled_data(tvb, offset, pinfo, "Reassembled CBCH message",
 388                                                  frag_data, &cbch_frag_items, NULL, cbch_tree);
 389             break;
 390
 391         case 0x0F:
 392             proto_tree_add_text(cbch_tree, tvb, offset, 1, "NULL message");
 393             call_dissector(data_handle, tvb, pinfo, cbch_tree);
 394             break;
 395
 396         default:
 397             proto_tree_add_text(cbch_tree, tvb, offset, 1, "reserved Sequence Number");
 398             call_dissector(data_handle, tvb, pinfo, cbch_tree);
 399             break;
 400         }
 401         if (reass_tvb)
 402         {
 403             /* Reassembled */
 404
 405             /* the tvb contains the reassmbled message prepended with the sequence number octet from the first block
 406                We use this to determine whether this is a normal message or a scheduling message */
 407             offset = 0;
 408
 409             octet = tvb_get_guint8(reass_tvb, offset++);
 410             msg_tvb = tvb_new_subset_remaining(reass_tvb, offset);
 411
 412             if (octet & 0x08)
 413             {
 414                 dissect_schedule_message(msg_tvb, pinfo, tree);
 415             }
 416             else
 417             {
 418                 call_dissector(cbs_handle, msg_tvb, pinfo, tree);
 419             }
 420         }
 421     }
 422     else
 423     {
 424         proto_tree_add_text(cbch_tree, tvb, offset, 1, "invalid Link Protocol Discriminator");
 425         call_dissector(data_handle, tvb, pinfo, cbch_tree);
 426     }
 427 }
 428
 429 /* Register the protocol with Wireshark */
 430 void
 431 proto_register_gsm_cbch(void)
 432 {
 433     /* Setup list of header fields */
 434     static hf_register_info hf_smscb[] =
 435         {
 436             { &hf_gsm_cbch_spare_bit,
 437               { "GSM CBCH spare bit",  "gsm_cbch.block_type.spare",
 438                 FT_UINT8, BASE_HEX, NULL, 0x80,
 439                 NULL, HFILL}
 440             },
 441             { &hf_gsm_cbch_lpd,
 442               { "GSM CBCH Link Protocol Discriminator",  "gsm_cbch.block_type.lpd",
 443                 FT_UINT8, BASE_DEC, VALS(block_type_lpd_strings), 0x60,
 444                 NULL, HFILL}
 445             },
 446             { &hf_gsm_cbch_lb,
 447               { "GSM CBCH Last Block", "gsm_cbch.block_type.lb",
 448                 FT_UINT8, BASE_DEC, NULL, 0x10,
 449                 NULL, HFILL}
 450             },
 451             { &hf_gsm_cbch_seq_num,
 452               { "GSM CBCH Sequence Number",  "gsm_cbch.block_type.seq_num",
 453                 FT_UINT8, BASE_DEC, VALS(block_type_seq_num_values), 0x0F,
 454                 NULL, HFILL}
 455             },
 456             { &hf_gsm_cbch_sched_type,
 457               { "GSM CBCH Schedule Type", "gsm_cbch.sched_type",
 458                 FT_UINT8, BASE_DEC, VALS(sched_type_values), 0xC0,
 459                 NULL, HFILL}
 460             },
 461             { &hf_gsm_cbch_sched_begin_slot,
 462               { "GSM CBCH Schedule Begin slot", "gsm_cbch.schedule_begin",
 463                 FT_UINT8, BASE_DEC, NULL, 0x3F,
 464                 NULL, HFILL}
 465             },
 466             { &hf_gsm_cbch_sched_spare,
 467               { "GSM CBCH Schedule Spare Bits", "gsm_cbch.sched_spare",
 468                 FT_UINT8, BASE_DEC, NULL, 0xC0,
 469                 NULL, HFILL}
 470             },
 471             { &hf_gsm_cbch_sched_end_slot,
 472               { "GSM CBCH Schedule End Slot",   "gsm_cbch.sched_end",
 473                 FT_UINT8, BASE_DEC, NULL, 0x3F,
 474                 NULL, HFILL}
 475             },
 476 #if 0
 477             { &hf_gsm_cbch_sched_msg_id,
 478               { "GSM CBCH Schedule Message ID", "gsm_cbch.sched_msg_id",
 479                 FT_UINT16, BASE_DEC, NULL, 0x0,
 480                 NULL, HFILL}
 481             },
 482 #endif
 483             /* Fragment fields
 484              */
 485             { &hf_cbch_fragment_overlap,
 486               {   "Fragment overlap",
 487                   "gsm_cbch.fragment.overlap",
 488                   FT_BOOLEAN, BASE_NONE, NULL, 0x0,
 489                   "Fragment overlaps with other fragments", HFILL
 490               }
 491             },
 492             { &hf_cbch_fragment_overlap_conflict,
 493               {   "Conflicting data in fragment overlap",
 494                   "gsm_cbch.fragment.overlap.conflict",
 495                   FT_BOOLEAN, BASE_NONE, NULL, 0x0,
 496                   "Overlapping fragments contained conflicting data", HFILL
 497               }
 498             },
 499             { &hf_cbch_fragment_multiple_tails,
 500               {   "Multiple tail fragments found",
 501                   "gsm_cbch.fragment.multipletails",
 502                   FT_BOOLEAN, BASE_NONE, NULL, 0x0,
 503                   "Several tails were found when defragmenting the packet", HFILL
 504               }
 505             },
 506             { &hf_cbch_fragment_too_long_fragment,
 507               {   "Fragment too long",
 508                   "gsm_cbch.fragment.toolongfragment",
 509                   FT_BOOLEAN, BASE_NONE, NULL, 0x0,
 510                   "Fragment contained data past end of packet", HFILL
 511               }
 512             },
 513             { &hf_cbch_fragment_error,
 514               {   "Defragmentation error",
 515                   "gsm_cbch.fragment.error",
 516                   FT_FRAMENUM, BASE_NONE, NULL, 0x0,
 517                   "Defragmentation error due to illegal fragments", HFILL
 518               }
 519             },
 520             { &hf_cbch_fragment_count,
 521               {   "Fragmentation count",
 522                   "gsm_cbch.fragment.count",
 523                   FT_UINT32, BASE_DEC, NULL, 0x0,
 524                   "Count of CBCH Fragments", HFILL
 525               }
 526             },
 527             { &hf_cbch_reassembled_in,
 528               {   "Reassembled in",
 529                   "gsm_cbch.reassembled.in",
 530                   FT_FRAMENUM, BASE_NONE, NULL, 0x0,
 531                   "CBCH fragments are reassembled in the given packet", HFILL
 532               }
 533             },
 534             { &hf_cbch_reassembled_length,
 535               {   "Reassembled message length is one less than indicated here",
 536                   "gsm_cbch.reassembled.length",
 537                   FT_UINT32, BASE_DEC, NULL, 0x0,
 538                   "The total length of the reassembled message", HFILL
 539               }
 540             },
 541             { &hf_cbch_fragment,
 542               {   "CBCH Fragment",
 543                   "gsm_cbch.fragment",
 544                   FT_FRAMENUM, BASE_NONE, NULL, 0x0,
 545                   NULL, HFILL
 546               }
 547             },
 548             { &hf_cbch_fragments,
 549               {   "CBCH Fragments",
 550                   "gsm_cbch.fragments",
 551                   FT_NONE, BASE_NONE, NULL, 0x0,
 552                   NULL, HFILL
 553               }
 554             }
 555         };
 556
 557 /* Setup protocol subtree array */
 558     static gint *ett[] = {
 559         &ett_cbch_msg,
 560         &ett_schedule_msg,
 561         &ett_schedule_new_msg,
 562         &ett_cbch_fragment,
 563         &ett_cbch_fragments,
 564     };
 565
 566     /* Register the protocol name and description */
 567     proto_cbch = proto_register_protocol("GSM Cell Broadcast Channel", "GSM CBCH", "gsm_cbch");
 568     proto_register_field_array(proto_cbch, hf_smscb, array_length(hf_smscb));
 569
 570     /* subdissector code */
 571     register_dissector("gsm_cbch", dissect_cbch, proto_cbch);
 572     register_init_routine(cbch_defragment_init);
 573
 574     /* subtree array */
 575     proto_register_subtree_array(ett, array_length(ett));
 576 }
 577
 578 void
 579 proto_reg_handoff_gsm_cbch(void)
 580 {
 581     data_handle = find_dissector("data");
 582     cbs_handle  = find_dissector("gsm_cbs");
 583 }