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  * Wireshark - Network traffic analyzer
   6  * By Gerald Combs <gerald@wireshark.org>
   7  * Copyright 1998 Gerald Combs
   8  *
   9  * SPDX-License-Identifier: GPL-2.0-or-later
  10  */
  11
  12 #include "config.h"
  13
  14 #include <epan/packet.h>
  15 #include <wsutil/bitswap.h>
  16 #include <epan/asn1.h> /* needed for packet-gsm_map.h */
  17
  18 #include "packet-cell_broadcast.h"
  19 #include "packet-gsm_map.h"
  20
  21 void proto_register_bmc(void);
  22
  23 static int dissect_bmc_cbs_message     (tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree);
  24 static int dissect_bmc_schedule_message(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree);
  25 static int dissect_bmc_cbs41_message   (tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree);
  26
  27 static int proto_bmc;
  28 static int hf_bmc_message_type;
  29 static int hf_bmc_message_id;
  30 static int hf_bmc_serial_number;
  31 /* static int hf_bmc_data_coding_scheme; */
  32 /* static int hf_bmc_cb_data; */
  33 static int hf_bmc_offset_to_begin_ctch_bs_index;
  34 static int hf_bmc_length_of_cbs_schedule_period;
  35 static int hf_bmc_new_message_bitmap;
  36 static int hf_bmc_message_description_type;
  37 static int hf_bmc_offset_to_ctch_bs_index_of_first_transmission;
  38 static int hf_bmc_broadcast_address;
  39 static int hf_bmc_cb_data41;
  40 static int hf_bmc_future_extension_bitmap;
  41 static int hf_bmc_length_of_serial_number_list;
  42 static int hf_bmc_ctch_bs_index;
  43
  44 #define MESSAGE_TYPE_CBS_MESSAGE        1
  45 #define MESSAGE_TYPE_SCHEDULE_MESSAGE   2
  46 #define MESSAGE_TYPE_CBS41_MESSAGE      3
  47
  48 static const value_string message_type_vals[] = {
  49     {MESSAGE_TYPE_CBS_MESSAGE, "CBS Message"},
  50     {MESSAGE_TYPE_SCHEDULE_MESSAGE, "Schedule Message"},
  51     {MESSAGE_TYPE_CBS41_MESSAGE, "CBS41 Message"},
  52     {0, NULL}
  53 };
  54
  55 static const value_string message_description_type_vals[] = {
  56     {0, "Repetition of new BMC CBS message within schedule period"},
  57     {1, "New BMC CBS message (a BMC CBS message never previously sent)"},
  58     {2, "Reading advised"},
  59     {3, "Reading optional"},
  60     {4, "Repetition of old BMC CBS message within schedule period"},
  61     {5, "Old BMC CBS message (repetition of a BMC CBS message sent in a previous schedule period)"},
  62     {6, "Schedule message"},
  63     {7, "CBS41 message"},
  64     {8, "no message"},
  65     {0, NULL}
  66 };
  67
  68 static int ett_bmc;
  69 static int ett_bmc_message_description;
  70
  71 static int
  72 dissect_bmc(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
  73 {
  74     uint8_t     message_type;
  75     uint8_t    *reversing_buffer;
  76     int         offset = 0;
  77     int         len;
  78     proto_item *ti;
  79     proto_tree *bmc_tree;
  80     tvbuff_t   *bit_reversed_tvb;
  81
  82     col_set_str(pinfo->cinfo, COL_PROTOCOL, "BMC");
  83     col_clear(pinfo->cinfo, COL_INFO);
  84
  85     ti = proto_tree_add_item(tree, proto_bmc, tvb, 0, -1, ENC_NA);
  86     bmc_tree = proto_item_add_subtree(ti, ett_bmc);
  87
  88     /* Needs bit-reversing. Create a new buffer, copy the message to it and bit-reverse */
  89     len = tvb_reported_length(tvb);
  90     reversing_buffer = (uint8_t *)tvb_memdup(pinfo->pool, tvb, offset, len);
  91     bitswap_buf_inplace(reversing_buffer, len);
  92
  93     /* Make this new buffer part of the display and provide a way to dispose of it */
  94     bit_reversed_tvb = tvb_new_child_real_data(tvb, reversing_buffer, len, len);
  95     add_new_data_source(pinfo, bit_reversed_tvb, "Bit-reversed Data");
  96
  97     message_type = tvb_get_uint8(bit_reversed_tvb, offset);
  98     proto_tree_add_item(bmc_tree, hf_bmc_message_type, bit_reversed_tvb, offset, 1, ENC_BIG_ENDIAN);
  99     offset++;
 100     col_add_str(pinfo->cinfo, COL_INFO, val_to_str(message_type, message_type_vals,"Reserved 0x%02x"));
 101
 102     switch (message_type) {
 103         case MESSAGE_TYPE_CBS_MESSAGE:
 104             offset = dissect_bmc_cbs_message(bit_reversed_tvb, pinfo, bmc_tree);
 105             break;
 106
 107         case MESSAGE_TYPE_SCHEDULE_MESSAGE:
 108             offset = dissect_bmc_schedule_message(bit_reversed_tvb, pinfo, bmc_tree);
 109             break;
 110
 111         case MESSAGE_TYPE_CBS41_MESSAGE:
 112             offset = dissect_bmc_cbs41_message(bit_reversed_tvb, pinfo, bmc_tree);
 113             break;
 114
 115         default:
 116             break;
 117     }
 118
 119     return offset;
 120 }
 121
 122 static int
 123 dissect_bmc_cbs_message(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 124 {
 125     tvbuff_t *cell_broadcast_tvb;
 126     int       offset = 1;
 127
 128     dissect_cbs_message_identifier(tvb, tree, offset);
 129     offset += 2;
 130
 131     dissect_cbs_serial_number(tvb, tree, offset);
 132     offset += 2;
 133
 134     dissect_cbs_data_coding_scheme(tvb, pinfo, tree, offset);
 135     offset += 1;
 136
 137     cell_broadcast_tvb = tvb_new_subset_remaining(tvb, offset);
 138     dissect_umts_cell_broadcast_message(cell_broadcast_tvb, pinfo, tree, NULL);
 139     offset = tvb_reported_length(cell_broadcast_tvb);
 140
 141     return offset;
 142 }
 143
 144 static int
 145 dissect_bmc_schedule_message(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree)
 146 {
 147     int         offset = 1, i, saved_offset;
 148     uint8_t     new_message_bitmap_len;
 149     uint8_t     length_of_cbs_schedule_period;
 150     uint8_t     message_description_type;
 151     uint8_t     future_extension_bitmap;
 152     uint8_t     length_of_serial_number_list;
 153     uint8_t     entry;
 154     uint8_t     bit;
 155     proto_tree *message_description_tree;
 156     proto_item *ti;
 157
 158     proto_tree_add_item(tree, hf_bmc_offset_to_begin_ctch_bs_index, tvb, offset, 1, ENC_BIG_ENDIAN);
 159     offset += 1;
 160
 161     length_of_cbs_schedule_period = tvb_get_uint8(tvb,offset);
 162     proto_tree_add_item(tree, hf_bmc_length_of_cbs_schedule_period, tvb, offset, 1, ENC_BIG_ENDIAN);
 163     offset += 1;
 164
 165     new_message_bitmap_len = length_of_cbs_schedule_period>>3;
 166     if (length_of_cbs_schedule_period & 0x7)
 167         new_message_bitmap_len += 1;
 168
 169     proto_tree_add_item(tree, hf_bmc_new_message_bitmap, tvb, offset, new_message_bitmap_len, ENC_NA);
 170     offset += new_message_bitmap_len;
 171
 172     message_description_tree = proto_tree_add_subtree(tree, tvb, offset, 0,
 173                     ett_bmc_message_description, &ti, "Message Description" );
 174     saved_offset = offset;
 175
 176     bit=1;
 177     for (i=0; i<new_message_bitmap_len; i++) {
 178         for(; bit<=length_of_cbs_schedule_period; bit++) {
 179             message_description_type = tvb_get_uint8(tvb,offset);
 180             proto_tree_add_uint_format(message_description_tree, hf_bmc_message_description_type,
 181                                        tvb, offset, 1, message_description_type,
 182                                        "Message %d Message Description Type: %s (%d)",
 183                                        bit,
 184                                        val_to_str_const(message_description_type, message_description_type_vals,"Unknown"),
 185                                        message_description_type);
 186             offset += 1;
 187
 188             if ((message_description_type==1) || (message_description_type==5)) {
 189                 proto_tree_add_item(message_description_tree, hf_bmc_message_id, tvb, offset, 2, ENC_BIG_ENDIAN);
 190                 offset += 2;
 191             }
 192             else if ((message_description_type==0) || (message_description_type==4)) {
 193                 proto_tree_add_item(message_description_tree, hf_bmc_offset_to_ctch_bs_index_of_first_transmission,
 194                                     tvb, offset, 1, ENC_BIG_ENDIAN);
 195                 offset += 1;
 196             }
 197         }
 198     }
 199     proto_item_set_len(ti, offset-saved_offset);
 200
 201     if (tvb_reported_length_remaining(tvb,offset)) {
 202         future_extension_bitmap = tvb_get_uint8(tvb,offset);
 203         proto_tree_add_item(tree, hf_bmc_future_extension_bitmap, tvb, offset, 1, ENC_BIG_ENDIAN);
 204         offset += 1;
 205         if (future_extension_bitmap & 0x01) {
 206             length_of_serial_number_list = tvb_get_uint8(tvb,offset);
 207             proto_tree_add_item(tree, hf_bmc_length_of_serial_number_list, tvb, offset, 1, ENC_BIG_ENDIAN);
 208             offset += 1;
 209
 210             for (entry=0; entry<length_of_serial_number_list; entry++) {
 211                 proto_tree_add_item(tree, hf_bmc_serial_number, tvb, offset, 2, ENC_BIG_ENDIAN);
 212                 offset += 2;
 213
 214                 proto_tree_add_item(tree, hf_bmc_ctch_bs_index, tvb, offset, 1, ENC_BIG_ENDIAN);
 215                 offset += 1;
 216             }
 217         }
 218     }
 219
 220     return offset;
 221 }
 222
 223 static int
 224 dissect_bmc_cbs41_message(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree)
 225 {
 226     int offset=1;
 227
 228     proto_tree_add_item(tree, hf_bmc_broadcast_address, tvb, offset, 5, ENC_NA);
 229     offset += 5;
 230
 231     proto_tree_add_item(tree, hf_bmc_cb_data41, tvb, offset, tvb_reported_length_remaining(tvb,offset), ENC_NA);
 232     offset = tvb_reported_length(tvb);
 233
 234     return offset;
 235 }
 236
 237 void
 238 proto_register_bmc(void)
 239 {
 240     static hf_register_info hf[] = {
 241         { &hf_bmc_message_type,
 242             { "Message Type", "bmc.message_type",
 243             FT_UINT8, BASE_DEC, VALS(message_type_vals), 0,
 244             NULL, HFILL }
 245         },
 246         { &hf_bmc_message_id,
 247             { "Message ID", "bmc.message_id",
 248             FT_UINT16, BASE_HEX, NULL, 0,
 249             NULL, HFILL }
 250         },
 251         { &hf_bmc_serial_number,
 252             { "Serial Number", "bmc.serial_number",
 253             FT_UINT16, BASE_HEX, NULL, 0,
 254             NULL, HFILL }
 255         },
 256 #if 0
 257         { &hf_bmc_data_coding_scheme,
 258             { "Data Coding Scheme", "bmc.data_coding_scheme",
 259             FT_UINT8, BASE_HEX, NULL, 0,
 260             NULL, HFILL }
 261         },
 262         { &hf_bmc_cb_data,
 263             { "CB Data", "bmc.cb_data",
 264             FT_BYTES, BASE_NONE, NULL, 0,
 265             NULL, HFILL }
 266         },
 267 #endif
 268         { &hf_bmc_offset_to_begin_ctch_bs_index,
 269             { "Offset to Begin CTCH Block Set Index", "bmc.offset_to_begin_ctch_bs_index",
 270             FT_UINT8, BASE_DEC, NULL, 0,
 271             NULL, HFILL }
 272         },
 273         { &hf_bmc_length_of_cbs_schedule_period,
 274             { "Length of CBS Schedule Period", "bmc.length_of_cbs_schedule_period",
 275             FT_UINT8, BASE_DEC, NULL, 0,
 276             NULL, HFILL }
 277         },
 278         { &hf_bmc_new_message_bitmap,
 279             { "New Message Bitmap", "bmc.new_message_bitmap",
 280             FT_BYTES, BASE_NONE, NULL, 0,
 281             NULL, HFILL }
 282         },
 283         { &hf_bmc_message_description_type,
 284             { "Message Description Type", "bmc.message_description_type",
 285             FT_UINT8, BASE_DEC, VALS(message_description_type_vals), 0,
 286             NULL, HFILL }
 287         },
 288         { &hf_bmc_offset_to_ctch_bs_index_of_first_transmission,
 289             { "Offset to CTCH BS index of first transmission", "bmc.offset_to_ctch_bs_index_of_first_transmission",
 290             FT_UINT8, BASE_DEC, NULL, 0,
 291             NULL, HFILL }
 292         },
 293         { &hf_bmc_broadcast_address,
 294             { "Broadcast Address", "bmc.broadcast_address",
 295             FT_BYTES, BASE_NONE, NULL, 0,
 296             NULL, HFILL }
 297         },
 298         { &hf_bmc_cb_data41,
 299             { "CB Data41", "bmc.cb_data41",
 300             FT_BYTES, BASE_NONE, NULL, 0,
 301             NULL, HFILL }
 302         },
 303         { &hf_bmc_future_extension_bitmap,
 304             { "Future Extension Bitmap", "bmc.future_extension_bitmap",
 305             FT_UINT8, BASE_DEC, NULL, 0,
 306             NULL, HFILL }
 307         },
 308         { &hf_bmc_length_of_serial_number_list,
 309             { "Length of Serial Number List", "bmc.length_of_serial_number_list",
 310             FT_UINT8, BASE_DEC, NULL, 0,
 311             NULL, HFILL }
 312         },
 313         { &hf_bmc_ctch_bs_index,
 314             { "CTCH BS Index", "bmc.ctch_bs_index",
 315             FT_UINT8, BASE_DEC, NULL, 0,
 316             NULL, HFILL }
 317         }
 318     };
 319
 320     static int *ett[] = {
 321         &ett_bmc,
 322         &ett_bmc_message_description
 323     };
 324
 325     proto_bmc = proto_register_protocol("Broadcast/Multicast Control", "BMC", "bmc");
 326     register_dissector("bmc", dissect_bmc, proto_bmc);
 327
 328     proto_register_field_array(proto_bmc, hf, array_length(hf));
 329     proto_register_subtree_array(ett, array_length(ett));
 330 }
 331
 332 /*
 333  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 334  *
 335  * Local variables:
 336  * c-basic-offset: 4
 337  * tab-width: 8
 338  * indent-tabs-mode: nil
 339  * End:
 340  *
 341  * vi: set shiftwidth=4 tabstop=8 expandtab:
 342  * :indentSize=4:tabSize=8:noTabs=true:
 343  */