path: root/epan/dissectors/packet-usb-audio.c

/* packet-usb-audio.c
 *
 * $Id$
 *
 * usb audio dissector
 * Tomasz Mon 2012
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include "config.h"

#include <glib.h>
#include <epan/conversation.h>
#include <epan/expert.h>
#include <epan/packet.h>
#include <epan/reassemble.h>
#include "packet-usb.h"

/* protocols and header fields */
static int proto_usb_audio = -1;
static int hf_midi_cable_number = -1;
static int hf_midi_code_index = -1;
static int hf_midi_event = -1;

static reassembly_table midi_data_reassembly_table;

static gint ett_usb_audio      = -1;
static gint ett_usb_audio_desc = -1;

static dissector_handle_t sysex_handle;

#define AUDIO_SUBCLASS_UNDEFINED	0x00
#define AUDIO_SUBCLASS_AUDIOCONTROL	0x01
#define AUDIO_SUBCLASS_AUDIOSTREAMING	0x02
#define AUDIO_SUBCLASS_MIDISTREAMING	0x03

#if 0
static const value_string usb_audio_subclass_vals[] = {
    {AUDIO_SUBCLASS_UNDEFINED,		"SUBCLASS_UNDEFINED"},
    {AUDIO_SUBCLASS_AUDIOCONTROL,	"AUDIOCONSTROL"},
    {AUDIO_SUBCLASS_AUDIOSTREAMING,	"AUDIOSTREAMING"},
    {AUDIO_SUBCLASS_MIDISTREAMING,	"MIDISTREAMING"},
    {0, NULL}
};
#endif

static const value_string code_index_vals[] = {
    { 0x0, "Miscellaneous (Reserved)" },
    { 0x1, "Cable events (Reserved)" },
    { 0x2, "Two-byte System Common message" },
    { 0x3, "Three-byte System Common message" },
    { 0x4, "SysEx starts or continues" },
    { 0x5, "SysEx ends with following single byte/Single-byte System Common Message" },
    { 0x6, "SysEx ends with following two bytes" },
    { 0x7, "SysEx ends with following three bytes" },
    { 0x8, "Note-off" },
    { 0x9, "Note-on" },
    { 0xA, "Poly-KeyPress" },
    { 0xB, "Control Change" },
    { 0xC, "Program Change" },
    { 0xD, "Channel Pressure" },
    { 0xE, "PitchBend Change" },
    { 0xF, "Single Byte" },
    { 0, NULL }
};

/* USB audio specification, section A.8 */
#define CS_INTERFACE       0x24
#define CS_ENDPOINT        0x25

static const value_string aud_descriptor_type_vals[] = {
        {CS_INTERFACE, "audio class interface"},
        {CS_ENDPOINT, "audio class endpoint"},
        {0,NULL}
};
static value_string_ext aud_descriptor_type_vals_ext =
    VALUE_STRING_EXT_INIT(aud_descriptor_type_vals);

static int hf_sysex_msg_fragments = -1;
static int hf_sysex_msg_fragment = -1;
static int hf_sysex_msg_fragment_overlap = -1;
static int hf_sysex_msg_fragment_overlap_conflicts = -1;
static int hf_sysex_msg_fragment_multiple_tails = -1;
static int hf_sysex_msg_fragment_too_long_fragment = -1;
static int hf_sysex_msg_fragment_error = -1;
static int hf_sysex_msg_fragment_count = -1;
static int hf_sysex_msg_reassembled_in = -1;
static int hf_sysex_msg_reassembled_length = -1;
static int hf_sysex_msg_reassembled_data = -1;

static gint ett_sysex_msg_fragment = -1;
static gint ett_sysex_msg_fragments = -1;

static expert_field ei_usb_audio_undecoded = EI_INIT;

static const fragment_items sysex_msg_frag_items = {
    /* Fragment subtrees */
    &ett_sysex_msg_fragment,
    &ett_sysex_msg_fragments,
    /* Fragment fields */
    &hf_sysex_msg_fragments,
    &hf_sysex_msg_fragment,
    &hf_sysex_msg_fragment_overlap,
    &hf_sysex_msg_fragment_overlap_conflicts,
    &hf_sysex_msg_fragment_multiple_tails,
    &hf_sysex_msg_fragment_too_long_fragment,
    &hf_sysex_msg_fragment_error,
    &hf_sysex_msg_fragment_count,
    /* Reassembled in field */
    &hf_sysex_msg_reassembled_in,
    /* Reassembled length field */
    &hf_sysex_msg_reassembled_length,
    &hf_sysex_msg_reassembled_data,
    /* Tag */
    "Message fragments"
};

static inline gboolean
is_sysex_code(guint8 code)
{
    return (code == 0x04 || code == 0x05 || code == 0x06 || code == 0x07);
}

static gboolean
is_last_sysex_packet_in_tvb(tvbuff_t *tvb, gint offset)
{
    gboolean last = TRUE;
    gint length = tvb_length(tvb);

    offset += 4;
    while (offset < length)
    {
        guint8 code = tvb_get_guint8(tvb, offset);
        code &= 0x0F;

        if (is_sysex_code(code))
        {
            last = FALSE;
            break;
        }

        offset += 4;
    }

    return last;
}

static void
dissect_usb_midi_event(tvbuff_t *tvb, packet_info *pinfo,
                       proto_tree *usb_audio_tree, proto_tree *parent_tree,
                       gint offset)
{
    guint8 code;
    guint8 cable;
    gboolean save_fragmented;
    proto_tree *tree = NULL;

    col_set_str(pinfo->cinfo, COL_INFO, "USB-MIDI Event Packets");

    code = tvb_get_guint8(tvb, offset);
    cable = (code & 0xF0) >> 4;
    code &= 0x0F;

    if (parent_tree)
    {
        proto_item *ti = NULL;

        ti = proto_tree_add_protocol_format(usb_audio_tree, proto_usb_audio, tvb, offset, 4, "USB Midi Event Packet");
        tree = proto_item_add_subtree(ti, ett_usb_audio);
        proto_tree_add_item(tree, hf_midi_cable_number, tvb, offset, 1, ENC_BIG_ENDIAN);
        proto_tree_add_item(tree, hf_midi_code_index, tvb, offset, 1, ENC_BIG_ENDIAN);
        proto_tree_add_item(tree, hf_midi_event, tvb, offset+1, 3, ENC_BIG_ENDIAN);
    }

    save_fragmented = pinfo->fragmented;

    /* Reassemble SysEx commands */
    if (is_sysex_code(code))
    {
        tvbuff_t* new_tvb = NULL;
        fragment_head *frag_sysex_msg = NULL;

        pinfo->fragmented = TRUE;

        if (code == 0x04)
        {
            frag_sysex_msg = fragment_add_seq_next(&midi_data_reassembly_table,
                tvb, offset+1,
                pinfo,
                cable, /* ID for fragments belonging together */
                NULL,
                3,
                TRUE);
        }
        else
        {
            frag_sysex_msg = fragment_add_seq_next(&midi_data_reassembly_table,
                tvb, offset+1,
                pinfo,
                cable, /* ID for fragments belonging together */
                NULL,
                (gint)(code - 4),
                FALSE);
        }

        if (is_last_sysex_packet_in_tvb(tvb, offset))
        {
            new_tvb = process_reassembled_data(tvb, offset+1, pinfo,
                "Reassembled Message", frag_sysex_msg, &sysex_msg_frag_items,
                NULL, usb_audio_tree);

            if (code != 0x04) { /* Reassembled */
                col_append_str(pinfo->cinfo, COL_INFO,
                        " (SysEx Reassembled)");
            } else { /* Not last packet of reassembled Short Message */
                col_append_str(pinfo->cinfo, COL_INFO,
                        " (SysEx fragment)");
            }

            if (new_tvb)
            {
                call_dissector(sysex_handle, new_tvb, pinfo, parent_tree);
            }
        }
    }

    pinfo->fragmented = save_fragmented;
}


static gint
dissect_usb_audio_descriptor(tvbuff_t *tvb, packet_info *pinfo _U_,
        proto_tree *tree, void *data _U_)
{
    gint        offset = 0;
    guint8      descriptor_len;
    guint8      descriptor_type;
    proto_item *item = NULL;
    proto_tree *desc_tree;

    descriptor_len  = tvb_get_guint8(tvb, offset);
    descriptor_type = tvb_get_guint8(tvb, offset+1);

    if (descriptor_type == CS_INTERFACE) {
        item = proto_tree_add_text(tree, tvb, offset, descriptor_len,
                "AUDIO CONTROL INTERFACE DESCRIPTOR");
    }
    else if (descriptor_type == CS_ENDPOINT) {
        item = proto_tree_add_text(tree, tvb, offset, descriptor_len,
                "AUDIO CONTROL ENDPOINT DESCRIPTOR");
    }
    else
        return 0;

    desc_tree = proto_item_add_subtree(item, ett_usb_audio_desc);

    dissect_usb_descriptor_header(desc_tree, tvb, offset,
            &aud_descriptor_type_vals_ext);

    return descriptor_len;
}


/* dissector for usb midi bulk data */
static int
dissect_usb_audio_bulk(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree, void* data)
{
    usb_conv_info_t *usb_conv_info = (usb_conv_info_t *)data;
    proto_tree *tree = NULL;
    guint offset;
    guint length = tvb_length(tvb);

    col_set_str(pinfo->cinfo, COL_PROTOCOL, "USBAUDIO");

    if (parent_tree)
    {
        proto_item *ti = NULL;

        ti = proto_tree_add_protocol_format(parent_tree, proto_usb_audio, tvb, 0, -1, "USB Audio");
        tree = proto_item_add_subtree(ti, ett_usb_audio);
    }

    switch (usb_conv_info->interfaceSubclass)
    {
        case AUDIO_SUBCLASS_MIDISTREAMING:
            offset = 0;
            col_set_str(pinfo->cinfo, COL_INFO, "USB-MIDI Event Packets");

            while (offset < length)
            {
                dissect_usb_midi_event(tvb, pinfo, tree, parent_tree, offset);
                offset += 4;
            }
            break;
        default:
            offset = 0;
            proto_tree_add_expert(tree, pinfo, &ei_usb_audio_undecoded, tvb, offset, length - offset);
    }

    return tvb_length(tvb);
}

static void
midi_data_reassemble_init(void)
{
    reassembly_table_init(&midi_data_reassembly_table,
                          &addresses_reassembly_table_functions);
}

void
proto_register_usb_audio(void)
{
    static hf_register_info hf[] = {
        { &hf_midi_cable_number,
            { "Cable Number", "usbaudio.midi.cable_number", FT_UINT8, BASE_HEX,
              NULL, 0xF0, NULL, HFILL }},
        { &hf_midi_code_index,
            { "Code Index", "usbaudio.midi.code_index", FT_UINT8, BASE_HEX,
              VALS(code_index_vals), 0x0F, NULL, HFILL }},
        { &hf_midi_event,
            { "MIDI Event", "usbaudio.midi.event", FT_UINT24, BASE_HEX,
              NULL, 0, NULL, HFILL }},

        { &hf_sysex_msg_fragments,
            { "Message fragments", "usbaudio.sysex.fragments",
              FT_NONE, BASE_NONE, NULL, 0x00, NULL, HFILL }},
        { &hf_sysex_msg_fragment,
            { "Message fragment", "usbaudio.sysex.fragment",
              FT_FRAMENUM, BASE_NONE, NULL, 0x00, NULL, HFILL }},
        { &hf_sysex_msg_fragment_overlap,
            { "Message fragment overlap", "usbaudio.sysex.fragment.overlap",
              FT_BOOLEAN, 0, NULL, 0x00, NULL, HFILL }},
        { &hf_sysex_msg_fragment_overlap_conflicts,
            { "Message fragment overlapping with conflicting data",
              "usbaudio.sysex.fragment.overlap.conflicts",
              FT_BOOLEAN, 0, NULL, 0x00, NULL, HFILL }},
        { &hf_sysex_msg_fragment_multiple_tails,
            { "Message has multiple tail fragments",
              "usbaudio.sysex.fragment.multiple_tails",
              FT_BOOLEAN, 0, NULL, 0x00, NULL, HFILL }},
        { &hf_sysex_msg_fragment_too_long_fragment,
            { "Message fragment too long", "usbaudio.sysex.fragment.too_long_fragment",
              FT_BOOLEAN, 0, NULL, 0x00, NULL, HFILL }},
        { &hf_sysex_msg_fragment_error,
            { "Message defragmentation error", "usbaudio.sysex.fragment.error",
              FT_FRAMENUM, BASE_NONE, NULL, 0x00, NULL, HFILL }},
        { &hf_sysex_msg_fragment_count,
            { "Message fragment count", "usbaudio.sysex.fragment.count",
              FT_UINT32, BASE_DEC, NULL, 0x00, NULL, HFILL }},
        { &hf_sysex_msg_reassembled_in,
            { "Reassembled in", "usbaudio.sysex.reassembled.in",
              FT_FRAMENUM, BASE_NONE, NULL, 0x00, NULL, HFILL }},
        { &hf_sysex_msg_reassembled_length,
            { "Reassembled length", "usbaudio.sysex.reassembled.length",
              FT_UINT32, BASE_DEC, NULL, 0x00, NULL, HFILL }},
        { &hf_sysex_msg_reassembled_data,
            { "Reassembled data", "usbaudio.sysex.reassembled.data",
              FT_BYTES, BASE_NONE, NULL, 0x00, NULL, HFILL }},
    };

    static gint *usb_audio_subtrees[] = {
        &ett_usb_audio,
        &ett_usb_audio_desc,
        &ett_sysex_msg_fragment,
        &ett_sysex_msg_fragments
    };

    static ei_register_info ei[] = {
        { &ei_usb_audio_undecoded, { "usbaudio.undecoded", PI_UNDECODED, PI_WARN, "Not dissected yet (report to wireshark.org)", EXPFILL }},
    };

    expert_module_t* expert_usb_audio;

    proto_usb_audio = proto_register_protocol("USB Audio", "USBAUDIO", "usbaudio");
    proto_register_field_array(proto_usb_audio, hf, array_length(hf));
    proto_register_subtree_array(usb_audio_subtrees, array_length(usb_audio_subtrees));
    expert_usb_audio = expert_register_protocol(proto_usb_audio);
    expert_register_field_array(expert_usb_audio, ei, array_length(ei));
    register_init_routine(&midi_data_reassemble_init);

    new_register_dissector("usbaudio", dissect_usb_audio_bulk, proto_usb_audio);
}

void
proto_reg_handoff_usb_audio(void)
{
    dissector_handle_t usb_audio_bulk_handle, usb_audio_descr_handle;

    usb_audio_descr_handle = new_create_dissector_handle(
            dissect_usb_audio_descriptor, proto_usb_audio);
    dissector_add_uint("usb.descriptor", IF_CLASS_AUDIO, usb_audio_descr_handle);

    usb_audio_bulk_handle = find_dissector("usbaudio");
    dissector_add_uint("usb.bulk", IF_CLASS_AUDIO, usb_audio_bulk_handle);

    sysex_handle = find_dissector("sysex");
}
/*
 * Editor modelines
 *
 * Local Variables:
 * c-basic-offset: 4
 * tab-width: 8
 * indent-tabs-mode: nil
 * End:
 *
 * ex: set shiftwidth=4 tabstop=8 expandtab:
 * :indentSize=4:tabSize=8:noTabs=true:
 */