epan/dissectors/packet-sbc.c

   1 /* packet-sbc.c
   2  * Routines for Bluetooth SBC dissection
   3  *
   4  * Copyright 2012, Michal Labedzki for Tieto Corporation
   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/expert.h>
  31 #include <epan/prefs.h>
  32
  33 #define CHANNELS_MONO          0x00
  34 #define CHANNELS_JOINT_STEREO  0x03
  35
  36 #define FREQUENCY_16000        0x00
  37 #define FREQUENCY_32000        0x01
  38 #define FREQUENCY_44100        0x02
  39 #define FREQUENCY_48000        0x03
  40
  41 static int proto_sbc = -1;
  42
  43 static int hf_sbc_fragmented                                               = -1;
  44 static int hf_sbc_starting_packet                                          = -1;
  45 static int hf_sbc_last_packet                                              = -1;
  46 static int hf_sbc_rfa                                                      = -1;
  47 static int hf_sbc_number_of_frames                                         = -1;
  48
  49 static int hf_sbc_syncword                                                 = -1;
  50 static int hf_sbc_sampling_frequency                                       = -1;
  51 static int hf_sbc_blocks                                                   = -1;
  52 static int hf_sbc_channel_mode                                             = -1;
  53 static int hf_sbc_allocation_method                                        = -1;
  54 static int hf_sbc_subbands                                                 = -1;
  55 static int hf_sbc_bitpool                                                  = -1;
  56 static int hf_sbc_crc_check                                                = -1;
  57
  58 static int hf_sbc_data                                                     = -1;
  59
  60 static gint ett_sbc             = -1;
  61 static gint ett_sbc_list        = -1;
  62
  63 static expert_field ei_sbc_syncword = EI_INIT;
  64
  65 extern value_string_ext media_codec_audio_type_vals_ext;
  66
  67 static const value_string sampling_frequency_vals[] = {
  68     { 0x00,  "16 kHz"},
  69     { 0x01,  "32 kHz"},
  70     { 0x02,  "44.1 kHz"},
  71     { 0x03,  "48 kHz"},
  72     { 0, NULL }
  73 };
  74
  75 static const value_string blocks_vals[] = {
  76     { 0x00,  "4"},
  77     { 0x01,  "8"},
  78     { 0x02,  "12"},
  79     { 0x03,  "16"},
  80     { 0, NULL }
  81 };
  82
  83 static const value_string channel_mode_vals[] = {
  84     { 0x00,  "Mono"},
  85     { 0x01,  "Dual Channel"},
  86     { 0x02,  "Stereo"},
  87     { 0x03,  "Joint Stereo"},
  88     { 0, NULL }
  89 };
  90
  91 static const value_string allocation_method_vals[] = {
  92     { 0x00,  "Loudness"},
  93     { 0x01,  "SNR"},
  94     { 0, NULL }
  95 };
  96
  97 static const value_string subbands_vals[] = {
  98     { 0x00,  "4"},
  99     { 0x01,  "8"},
 100     { 0, NULL }
 101 };
 102
 103
 104 static gint
 105 dissect_sbc(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
 106 {
 107     proto_item  *ti;
 108     proto_tree  *sbc_tree;
 109     proto_item  *pitem;
 110     proto_item  *ritem;
 111     proto_tree  *rtree;
 112     gint        offset = 0;
 113     guint8      number_of_frames;
 114     guint8      syncword;
 115     guint8      byte;
 116     guint8      blocks;
 117     guint8      channels;
 118     guint8      subbands;
 119     guint8      bitpool;
 120     guint       frequency;
 121     guint8      sbc_blocks;
 122     gint        sbc_channels;
 123     guint8      sbc_subbands;
 124     gint        val;
 125     gint        counter = 1;
 126     gint        frame_length;
 127     gint        expected_speed_data;
 128
 129     col_set_str(pinfo->cinfo, COL_PROTOCOL, "SBC");
 130
 131     ti = proto_tree_add_item(tree, proto_sbc, tvb, offset, -1, ENC_NA);
 132     sbc_tree = proto_item_add_subtree(ti, ett_sbc);
 133
 134     proto_tree_add_item(sbc_tree, hf_sbc_fragmented,       tvb, offset, 1, ENC_BIG_ENDIAN);
 135     proto_tree_add_item(sbc_tree, hf_sbc_starting_packet,  tvb, offset, 1, ENC_BIG_ENDIAN);
 136     proto_tree_add_item(sbc_tree, hf_sbc_last_packet,      tvb, offset, 1, ENC_BIG_ENDIAN);
 137     proto_tree_add_item(sbc_tree, hf_sbc_rfa,              tvb, offset, 1, ENC_BIG_ENDIAN);
 138     proto_tree_add_item(sbc_tree, hf_sbc_number_of_frames, tvb, offset, 1, ENC_BIG_ENDIAN);
 139     number_of_frames = tvb_get_guint8(tvb, offset) & 0x0F;
 140     offset += 1;
 141
 142     while (tvb_length_remaining(tvb, offset) > 0) {
 143         byte = tvb_get_guint8(tvb, offset + 1);
 144         frequency = (byte & 0xC0) >> 6;
 145         blocks = (byte & 0x30) >> 4;
 146         channels = (byte & 0x0C)>> 2;
 147         subbands = byte & 0x01;
 148
 149         bitpool = tvb_get_guint8(tvb, offset + 2);
 150
 151         if (channels == CHANNELS_MONO)
 152             sbc_channels = 1;
 153         else
 154             sbc_channels = 2;
 155
 156         switch (frequency) {
 157             case FREQUENCY_16000:
 158                 frequency = 16000;
 159                 break;
 160             case FREQUENCY_32000:
 161                 frequency = 32000;
 162                 break;
 163             case FREQUENCY_44100:
 164                 frequency = 44100;
 165                 break;
 166             case FREQUENCY_48000:
 167                 frequency = 48000;
 168                 break;
 169             default:
 170                 frequency = 0;
 171         }
 172
 173         sbc_subbands = 4 * (subbands + 1);
 174         sbc_blocks = 4 * (blocks + 1);
 175
 176         frame_length = (4 * sbc_subbands * sbc_channels) / 8;
 177         if (sbc_channels == 1)
 178             val = sbc_blocks * sbc_channels * bitpool;
 179         else
 180             val = (((channels == CHANNELS_JOINT_STEREO) ? 1 : 0) * sbc_subbands + sbc_blocks * bitpool);
 181
 182         frame_length += val / 8;
 183         if (val % 8)
 184             frame_length += 1;
 185
 186         expected_speed_data = (frame_length * frequency) / (sbc_subbands * sbc_blocks);
 187
 188         ritem = proto_tree_add_text(sbc_tree, tvb, offset, 4 + frame_length,
 189                 "Frame: %3u/%3u", counter, number_of_frames);
 190         rtree = proto_item_add_subtree(ritem, ett_sbc_list);
 191
 192         pitem = proto_tree_add_item(rtree, hf_sbc_syncword, tvb, offset, 1, ENC_BIG_ENDIAN);
 193         syncword = tvb_get_guint8(tvb, offset);
 194         if (syncword != 0x9C) {
 195             expert_add_info(pinfo, pitem, &ei_sbc_syncword);
 196         }
 197         offset += 1;
 198
 199         proto_tree_add_item(ritem, hf_sbc_sampling_frequency, tvb, offset, 1, ENC_BIG_ENDIAN);
 200         proto_tree_add_item(ritem, hf_sbc_blocks,             tvb, offset, 1, ENC_BIG_ENDIAN);
 201         proto_tree_add_item(ritem, hf_sbc_channel_mode,       tvb, offset, 1, ENC_BIG_ENDIAN);
 202         proto_tree_add_item(ritem, hf_sbc_allocation_method,  tvb, offset, 1, ENC_BIG_ENDIAN);
 203         proto_tree_add_item(ritem, hf_sbc_subbands,           tvb, offset, 1, ENC_BIG_ENDIAN);
 204         offset += 1;
 205
 206         proto_tree_add_item(ritem, hf_sbc_bitpool,            tvb, offset, 1, ENC_BIG_ENDIAN);
 207         offset += 1;
 208
 209         proto_tree_add_item(ritem, hf_sbc_crc_check,          tvb, offset, 1, ENC_BIG_ENDIAN);
 210         offset += 1;
 211
 212         proto_tree_add_item(ritem, hf_sbc_data,  tvb, offset, frame_length, ENC_BIG_ENDIAN);
 213         offset += frame_length;
 214
 215 /* TODO: expert_info for invalid CRC*/
 216
 217         pitem = proto_tree_add_text(ritem, tvb, offset, 0, "Expected speed data: %u KiB/s", expected_speed_data / 1024);
 218         PROTO_ITEM_SET_GENERATED(pitem);
 219
 220         counter += 1;
 221     }
 222
 223 /* TODO: more precise dissection: blocks, channels, subbands, padding  */
 224
 225     col_append_fstr(pinfo->cinfo, COL_INFO, " Frames=%u", number_of_frames);
 226
 227     return offset;
 228 }
 229
 230 void
 231 proto_register_sbc(void)
 232 {
 233     module_t *module;
 234     expert_module_t* expert_sbc;
 235
 236     static hf_register_info hf[] = {
 237         { &hf_sbc_fragmented,
 238             { "Fragmented",                      "sbc.fragmented",
 239             FT_BOOLEAN, 8, NULL, 0x80,
 240             NULL, HFILL }
 241         },
 242         { &hf_sbc_starting_packet,
 243             { "Starting Packet",                 "sbc.starting_packet",
 244             FT_BOOLEAN, 8, NULL, 0x40,
 245             NULL, HFILL }
 246         },
 247         { &hf_sbc_last_packet,
 248             { "Last Packet",                     "sbc.last_packet",
 249             FT_BOOLEAN, 8, NULL, 0x20,
 250             NULL, HFILL }
 251         },
 252         { &hf_sbc_rfa,
 253             { "RFA",                             "sbc.rfa",
 254             FT_BOOLEAN, 8, NULL, 0x10,
 255             NULL, HFILL }
 256         },
 257         { &hf_sbc_number_of_frames,
 258             { "Number of Frames",                "sbc.number_of_frames",
 259             FT_UINT8, BASE_DEC, NULL, 0x0F,
 260             NULL, HFILL }
 261         },
 262         { &hf_sbc_syncword,
 263             { "Sync Word",                       "sbc.syncword",
 264             FT_UINT8, BASE_HEX, NULL, 0x00,
 265             NULL, HFILL }
 266         },
 267         { &hf_sbc_sampling_frequency,
 268             { "Sampling Frequency",              "sbc.sampling_frequency",
 269             FT_UINT8, BASE_HEX, VALS(sampling_frequency_vals), 0xC0,
 270             NULL, HFILL }
 271         },
 272         { &hf_sbc_blocks,
 273             { "Blocks",                          "sbc.blocks",
 274             FT_UINT8, BASE_HEX, VALS(blocks_vals), 0x30,
 275             NULL, HFILL }
 276         },
 277         { &hf_sbc_channel_mode,
 278             { "Channel Mode",                    "sbc.channel_mode",
 279             FT_UINT8, BASE_HEX, VALS(channel_mode_vals), 0x0C,
 280             NULL, HFILL }
 281         },
 282         { &hf_sbc_allocation_method,
 283             { "Allocation Method",               "sbc.allocation_method",
 284             FT_UINT8, BASE_HEX, VALS(allocation_method_vals), 0x02,
 285             NULL, HFILL }
 286         },
 287         { &hf_sbc_subbands,
 288             { "Subbands",                        "sbc.subbands",
 289             FT_UINT8, BASE_HEX, VALS(subbands_vals), 0x01,
 290             NULL, HFILL }
 291         },
 292         { &hf_sbc_bitpool,
 293             { "Bitpool",                         "sbc.bitpool",
 294             FT_UINT8, BASE_DEC, NULL, 0x00,
 295             NULL, HFILL }
 296         },
 297         { &hf_sbc_crc_check,
 298             { "CRC Check",                       "sbc.crc_check",
 299             FT_UINT8, BASE_HEX, NULL, 0x00,
 300             NULL, HFILL }
 301         },
 302
 303         { &hf_sbc_data,
 304             { "Data",                            "sbc.data",
 305             FT_NONE, BASE_NONE, NULL, 0x00,
 306             NULL, HFILL }
 307         },
 308     };
 309
 310     static gint *ett[] = {
 311         &ett_sbc,
 312         &ett_sbc_list,
 313     };
 314
 315     static ei_register_info ei[] = {
 316         { &ei_sbc_syncword, { "sbc.syncword.unexpected", PI_PROTOCOL, PI_WARN, "Unexpected syncword", EXPFILL }},
 317     };
 318
 319     proto_sbc = proto_register_protocol("Bluetooth SBC Codec", "SBC", "sbc");
 320
 321     proto_register_field_array(proto_sbc, hf, array_length(hf));
 322     proto_register_subtree_array(ett, array_length(ett));
 323     expert_sbc = expert_register_protocol(proto_sbc);
 324     expert_register_field_array(expert_sbc, ei, array_length(ei));
 325
 326     new_register_dissector("sbc", dissect_sbc, proto_sbc);
 327
 328     module = prefs_register_protocol(proto_sbc, NULL);
 329     prefs_register_static_text_preference(module, "a2dp.version",
 330             "Bluetooth Audio Codec SBC version based on A2DP 1.3",
 331             "Version of codec supported by this dissector.");
 332 }
 333
 334 /*
 335  * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
 336  *
 337  * Local variables:
 338  * c-basic-offset: 4
 339  * tab-width: 8
 340  * indent-tabs-mode: nil
 341  * End:
 342  *
 343  * vi: set shiftwidth=4 tabstop=8 expandtab:
 344  * :indentSize=4:tabSize=8:noTabs=true:
 345  */