epan/dissectors/packet-bmc.c

   1 /* packet-bmc.c
   2  * Routines for Broadcast/Multicast Control dissection
   3  * Copyright 2011, Neil Piercy <Neil.Piercy@ipaccess.com>
   4  *
   5  * $Id$
   6  *
   7  * Wireshark - Network traffic analyzer
   8  * By Gerald Combs <gerald@wireshark.org>
   9  * Copyright 1998 Gerald Combs
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License along
  22  * with this program; if not, write to the Free Software Foundation, Inc.,
  23  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  24  */
  25
  26 #include "config.h"
  27
  28 #include <glib.h>
  29
  30 #include <epan/packet.h>
  31 #include <epan/bitswap.h>
  32 #include <epan/asn1.h> /* needed for packet-gsm_map.h */
  33
  34 #include "packet-cell_broadcast.h"
  35 #include "packet-gsm_map.h"
  36
  37 void proto_register_bmc(void);
  38
  39 static int dissect_bmc_cbs_message     (tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree);
  40 static int dissect_bmc_schedule_message(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree);
  41 static int dissect_bmc_cbs41_message   (tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree);
  42
  43 static int proto_bmc = -1;
  44 static int hf_bmc_message_type = -1;
  45 static int hf_bmc_message_id = -1;
  46 static int hf_bmc_serial_number = -1;
  47 /* static int hf_bmc_data_coding_scheme = -1; */
  48 /* static int hf_bmc_cb_data = -1; */
  49 static int hf_bmc_offset_to_begin_ctch_bs_index = -1;
  50 static int hf_bmc_length_of_cbs_schedule_period = -1;
  51 static int hf_bmc_new_message_bitmap = -1;
  52 static int hf_bmc_message_description_type = -1;
  53 static int hf_bmc_offset_to_ctch_bs_index_of_first_transmission = -1;
  54 static int hf_bmc_broadcast_address = -1;
  55 static int hf_bmc_cb_data41 = -1;
  56 static int hf_bmc_future_extension_bitmap = -1;
  57 static int hf_bmc_length_of_serial_number_list = -1;
  58 static int hf_bmc_ctch_bs_index = -1;
  59
  60 #define MESSAGE_TYPE_CBS_MESSAGE        1
  61 #define MESSAGE_TYPE_SCHEDULE_MESSAGE   2
  62 #define MESSAGE_TYPE_CBS41_MESSAGE      3
  63
  64 static const value_string message_type_vals[] = {
  65     {MESSAGE_TYPE_CBS_MESSAGE, "CBS Message"},
  66     {MESSAGE_TYPE_SCHEDULE_MESSAGE, "Schedule Message"},
  67     {MESSAGE_TYPE_CBS41_MESSAGE, "CBS41 Message"},
  68     {0, NULL}
  69 };
  70
  71 static const value_string message_description_type_vals[] = {
  72     {0, "Repetition of new BMC CBS message within schedule period"},
  73     {1, "New BMC CBS message (a BMC CBS message never previously sent)"},
  74     {2, "Reading advised"},
  75     {3, "Reading optional"},
  76     {4, "Repetition of old BMC CBS message within schedule period"},
  77     {5, "Old BMC CBS message (repetition of a BMC CBS message sent in a previous schedule period)"},
  78     {6, "Schedule message"},
  79     {7, "CBS41 message"},
  80     {8, "no message"},
  81     {0, NULL}
  82 };
  83
  84 static gint ett_bmc = -1;
  85 static gint ett_bmc_message_description = -1;
  86
  87 static int
  88 dissect_bmc(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
  89 {
  90     guint8      message_type;
  91     guint8     *p_rev, *reversing_buffer;
  92     gint        offset = 0;
  93     gint        i, len;
  94     proto_item *ti;
  95     proto_tree *bmc_tree;
  96     tvbuff_t   *bit_reversed_tvb;
  97
  98     col_set_str(pinfo->cinfo, COL_PROTOCOL, "BMC");
  99     col_clear(pinfo->cinfo, COL_INFO);
 100
 101     ti = proto_tree_add_item(tree, proto_bmc, tvb, 0, -1, ENC_NA);
 102     bmc_tree = proto_item_add_subtree(ti, ett_bmc);
 103
 104     /* Needs bit-reversing. Create a new buffer, copy the message to it and bit-reverse */
 105     len = tvb_length(tvb);
 106     reversing_buffer = (guint8 *)tvb_memdup(NULL, tvb, offset, len);
 107     p_rev = reversing_buffer;
 108     /* Entire message is bit reversed */
 109     for (i=0; i<len; i++, p_rev++)
 110         *p_rev = BIT_SWAP(*p_rev);
 111
 112     /* Make this new buffer part of the display and provide a way to dispose of it */
 113     bit_reversed_tvb = tvb_new_child_real_data(tvb, reversing_buffer, len, len);
 114     tvb_set_free_cb(bit_reversed_tvb, g_free);
 115     add_new_data_source(pinfo, bit_reversed_tvb, "Bit-reversed Data");
 116
 117     message_type = tvb_get_guint8(bit_reversed_tvb, offset);
 118     proto_tree_add_item(bmc_tree, hf_bmc_message_type, bit_reversed_tvb, offset, 1, ENC_BIG_ENDIAN);
 119     offset++;
 120     col_add_fstr(pinfo->cinfo, COL_INFO, "%s", val_to_str(message_type, message_type_vals,"Reserved 0x%02x"));
 121
 122     switch (message_type) {
 123         case MESSAGE_TYPE_CBS_MESSAGE:
 124             offset = dissect_bmc_cbs_message(bit_reversed_tvb, pinfo, bmc_tree);
 125             break;
 126
 127         case MESSAGE_TYPE_SCHEDULE_MESSAGE:
 128             offset = dissect_bmc_schedule_message(bit_reversed_tvb, pinfo, bmc_tree);
 129             break;
 130
 131         case MESSAGE_TYPE_CBS41_MESSAGE:
 132             offset = dissect_bmc_cbs41_message(bit_reversed_tvb, pinfo, bmc_tree);
 133             break;
 134
 135         default:
 136             break;
 137     }
 138
 139     return offset;
 140 }
 141
 142 static int
 143 dissect_bmc_cbs_message(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree)
 144 {
 145     tvbuff_t *cell_broadcast_tvb;
 146     gint      offset = 1;
 147
 148     dissect_cbs_message_identifier(tvb, tree, offset);
 149     offset += 2;
 150
 151     dissect_cbs_serial_number(tvb, tree, offset);
 152     offset += 2;
 153
 154     dissect_cbs_data_coding_scheme(tvb, pinfo, tree, offset);
 155     offset += 1;
 156
 157     cell_broadcast_tvb = tvb_new_subset_remaining(tvb, offset);
 158     dissect_umts_cell_broadcast_message(cell_broadcast_tvb, pinfo, tree);
 159     offset = tvb_length(cell_broadcast_tvb);
 160
 161     return offset;
 162 }
 163
 164 static int
 165 dissect_bmc_schedule_message(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree)
 166 {
 167     gint        offset = 1, i, saved_offset;
 168     guint8      new_message_bitmap_len;
 169     guint8      length_of_cbs_schedule_period;
 170     guint8      message_description_type;
 171     guint8      future_extension_bitmap;
 172     guint8      length_of_serial_number_list;
 173     guint8      entry;
 174     guint8      bit;
 175     proto_tree *message_description_tree;
 176     proto_item *ti;
 177
 178     proto_tree_add_item(tree, hf_bmc_offset_to_begin_ctch_bs_index, tvb, offset, 1, ENC_BIG_ENDIAN);
 179     offset += 1;
 180
 181     length_of_cbs_schedule_period = tvb_get_guint8(tvb,offset);
 182     proto_tree_add_item(tree, hf_bmc_length_of_cbs_schedule_period, tvb, offset, 1, ENC_BIG_ENDIAN);
 183     offset += 1;
 184
 185     new_message_bitmap_len = length_of_cbs_schedule_period>>3;
 186     if (length_of_cbs_schedule_period & 0x7)
 187         new_message_bitmap_len += 1;
 188
 189     proto_tree_add_item(tree, hf_bmc_new_message_bitmap, tvb, offset, new_message_bitmap_len, ENC_NA);
 190     offset += new_message_bitmap_len;
 191
 192     ti = proto_tree_add_text(tree, tvb, offset, 0, "Message Description" );
 193     message_description_tree = proto_item_add_subtree(ti, ett_bmc_message_description);
 194     saved_offset = offset;
 195
 196     bit=1;
 197     for (i=0; i<new_message_bitmap_len; i++) {
 198         for(; bit<=length_of_cbs_schedule_period; bit++) {
 199             message_description_type = tvb_get_guint8(tvb,offset);
 200             proto_tree_add_uint_format(message_description_tree, hf_bmc_message_description_type,
 201                                        tvb, offset, 1, message_description_type,
 202                                        "Message %d Message Description Type: %s (%d)",
 203                                        bit,
 204                                        val_to_str_const(message_description_type, message_description_type_vals,"Unknown"),
 205                                        message_description_type);
 206             offset += 1;
 207
 208             if ((message_description_type==1) || (message_description_type==5)) {
 209                 proto_tree_add_item(message_description_tree, hf_bmc_message_id, tvb, offset, 2, ENC_BIG_ENDIAN);
 210                 offset += 2;
 211             }
 212             else if ((message_description_type==0) || (message_description_type==4)) {
 213                 proto_tree_add_item(message_description_tree, hf_bmc_offset_to_ctch_bs_index_of_first_transmission,
 214                                     tvb, offset, 1, ENC_BIG_ENDIAN);
 215                 offset += 1;
 216             }
 217         }
 218     }
 219     proto_item_set_len(ti, offset-saved_offset);
 220
 221     if (tvb_length_remaining(tvb,offset)) {
 222         future_extension_bitmap = tvb_get_guint8(tvb,offset);
 223         proto_tree_add_item(tree, hf_bmc_future_extension_bitmap, tvb, offset, 1, ENC_BIG_ENDIAN);
 224         offset += 1;
 225         if (future_extension_bitmap & 0x01) {
 226             length_of_serial_number_list = tvb_get_guint8(tvb,offset);
 227             proto_tree_add_item(tree, hf_bmc_length_of_serial_number_list, tvb, offset, 1, ENC_BIG_ENDIAN);
 228             offset += 1;
 229
 230             for (entry=0; entry<length_of_serial_number_list; entry++) {
 231                 proto_tree_add_item(tree, hf_bmc_serial_number, tvb, offset, 2, ENC_BIG_ENDIAN);
 232                 offset += 2;
 233
 234                 proto_tree_add_item(tree, hf_bmc_ctch_bs_index, tvb, offset, 1, ENC_BIG_ENDIAN);
 235                 offset += 1;
 236             }
 237         }
 238     }
 239
 240     return offset;
 241 }
 242
 243 static int
 244 dissect_bmc_cbs41_message(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree)
 245 {
 246     gint offset=1;
 247
 248     proto_tree_add_item(tree, hf_bmc_broadcast_address, tvb, offset, 5, ENC_NA);
 249     offset += 5;
 250
 251     proto_tree_add_item(tree, hf_bmc_cb_data41, tvb, offset, tvb_length_remaining(tvb,offset), ENC_NA);
 252     offset = tvb_length(tvb);
 253
 254     return offset;
 255 }
 256
 257 void
 258 proto_register_bmc(void)
 259 {
 260     static hf_register_info hf[] = {
 261         { &hf_bmc_message_type,
 262             { "Message Type", "bmc.message_type",
 263             FT_UINT8, BASE_DEC, message_type_vals, 0,
 264             NULL, HFILL }
 265         },
 266         { &hf_bmc_message_id,
 267             { "Message ID", "bmc.message_id",
 268             FT_UINT16, BASE_HEX, NULL, 0,
 269             NULL, HFILL }
 270         },
 271         { &hf_bmc_serial_number,
 272             { "Serial Number", "bmc.serial_number",
 273             FT_UINT16, BASE_HEX, NULL, 0,
 274             NULL, HFILL }
 275         },
 276 #if 0
 277         { &hf_bmc_data_coding_scheme,
 278             { "Data Coding Scheme", "bmc.data_coding_scheme",
 279             FT_UINT8, BASE_HEX, NULL, 0,
 280             NULL, HFILL }
 281         },
 282         { &hf_bmc_cb_data,
 283             { "CB Data", "bmc.cb_data",
 284             FT_BYTES, BASE_NONE, NULL, 0,
 285             NULL, HFILL }
 286         },
 287 #endif
 288         { &hf_bmc_offset_to_begin_ctch_bs_index,
 289             { "Offset to Begin CTCH Block Set Index", "bmc.offset_to_begin_ctch_bs_index",
 290             FT_UINT8, BASE_DEC, NULL, 0,
 291             NULL, HFILL }
 292         },
 293         { &hf_bmc_length_of_cbs_schedule_period,
 294             { "Length of CBS Schedule Period", "bmc.length_of_cbs_schedule_period",
 295             FT_UINT8, BASE_DEC, NULL, 0,
 296             NULL, HFILL }
 297         },
 298         { &hf_bmc_new_message_bitmap,
 299             { "New Message Bitmap", "bmc.new_message_bitmap",
 300             FT_BYTES, BASE_NONE, NULL, 0,
 301             NULL, HFILL }
 302         },
 303         { &hf_bmc_message_description_type,
 304             { "Message Description Type", "bmc.message_description_type",
 305             FT_UINT8, BASE_DEC, message_description_type_vals, 0,
 306             NULL, HFILL }
 307         },
 308         { &hf_bmc_offset_to_ctch_bs_index_of_first_transmission,
 309             { "Offset to CTCH BS index of first transmission", "bmc.offset_to_ctch_bs_index_of_first_transmission",
 310             FT_UINT8, BASE_DEC, NULL, 0,
 311             NULL, HFILL }
 312         },
 313         { &hf_bmc_broadcast_address,
 314             { "Broadcast Address", "bmc.broadcast_address",
 315             FT_BYTES, BASE_NONE, NULL, 0,
 316             NULL, HFILL }
 317         },
 318         { &hf_bmc_cb_data41,
 319             { "CB Data41", "bmc.cb_data41",
 320             FT_BYTES, BASE_NONE, NULL, 0,
 321             NULL, HFILL }
 322         },
 323         { &hf_bmc_future_extension_bitmap,
 324             { "Future Extension Bitmap", "bmc.future_extension_bitmap",
 325             FT_UINT8, BASE_DEC, NULL, 0,
 326             NULL, HFILL }
 327         },
 328         { &hf_bmc_length_of_serial_number_list,
 329             { "Length of Serial Number List", "bmc.length_of_serial_number_list",
 330             FT_UINT8, BASE_DEC, NULL, 0,
 331             NULL, HFILL }
 332         },
 333         { &hf_bmc_ctch_bs_index,
 334             { "CTCH BS Index", "bmc.ctch_bs_index",
 335             FT_UINT8, BASE_DEC, NULL, 0,
 336             NULL, HFILL }
 337         }
 338     };
 339
 340     static gint *ett[] = {
 341         &ett_bmc,
 342         &ett_bmc_message_description
 343     };
 344
 345     proto_bmc = proto_register_protocol("Broadcast/Multicast Control", "BMC", "bmc");
 346     new_register_dissector("bmc", dissect_bmc, proto_bmc);
 347
 348     proto_register_field_array(proto_bmc, hf, array_length(hf));
 349     proto_register_subtree_array(ett, array_length(ett));
 350 }