path: root/epan/dissectors/packet-osc.c

/* packet-osc.c
 * Routines for "Open Sound Control" packet dissection
 * Copyright 2014 Hanspeter Portner <dev@open-music-kontrollers.ch>
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 1998 Gerald Combs
 *
 * 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.
 */

/*
 * Specification 1.0 (http://opensoundcontrol.org/spec-1_0)
 * - based on default argument types: i,f,s,b
 * - including widely used extension types: T,F,N,I,h,d,t,S,c,r,m
 */

#include "config.h"


#include <epan/packet.h>
#include <epan/prefs.h>
#include <epan/exceptions.h>
#include "packet-tcp.h"

void proto_register_osc(void);
void proto_reg_handoff_osc(void);

/* Open Sound Control (OSC) argument types enumeration */
typedef enum _OSC_Type {
    OSC_INT32   = 'i',
    OSC_FLOAT   = 'f',
    OSC_STRING  = 's',
    OSC_BLOB    = 'b',

    OSC_TRUE    = 'T',
    OSC_FALSE   = 'F',
    OSC_NIL     = 'N',
    OSC_BANG    = 'I',

    OSC_INT64   = 'h',
    OSC_DOUBLE  = 'd',
    OSC_TIMETAG = 't',

    OSC_SYMBOL  = 'S',
    OSC_CHAR    = 'c',
    OSC_RGBA    = 'r',
    OSC_MIDI    = 'm'
} OSC_Type;

/* characters not allowed in OSC path string */
static const char invalid_path_chars [] = {
    ' ', '#',
    '\0'
};

/* allowed characters in OSC format string */
static const char valid_format_chars [] = {
    OSC_INT32,  OSC_FLOAT,  OSC_STRING,  OSC_BLOB,
    OSC_TRUE,   OSC_FALSE,  OSC_NIL,     OSC_BANG,
    OSC_INT64,  OSC_DOUBLE, OSC_TIMETAG,
    OSC_SYMBOL, OSC_CHAR,   OSC_RGBA,    OSC_MIDI,
    '\0'
};

#define MIDI_STATUS_CONTROLLER 0xB0

/* Standard MIDI Message Type */
static const value_string MIDI_status [] = {
    { 0x00, "Invalid Message" },
    { 0x80, "Note Off" },
    { 0x90, "Note On" },
    { 0xA0, "Note Pressure" },
    { MIDI_STATUS_CONTROLLER, "Controller" },
    { 0xC0, "Program Change" },
    { 0xD0, "Channel Pressure" },
    { 0xE0, "Pitch Bender" },
    { 0xF0, "System Exclusive Begin" },
    { 0xF1, "MTC Quarter Frame" },
    { 0xF2, "Song Position" },
    { 0xF3, "Song Select" },
    { 0xF6, "Tune Request" },
    { 0xF8, "Clock" },
    { 0xFA, "Start" },
    { 0xFB, "Continue" },
    { 0xFC, "Stop" },
    { 0xFE, "Active Sensing" },
    { 0xFF, "Reset" },

    {0, NULL }
};
static value_string_ext MIDI_status_ext = VALUE_STRING_EXT_INIT(MIDI_status);

/* Standard MIDI Controller Numbers */
static const value_string MIDI_control [] = {
    { 0x00, "Bank Selection" },
    { 0x01, "Modulation" },
    { 0x02, "Breath" },
    { 0x04, "Foot" },
    { 0x05, "Portamento Time" },
    { 0x06, "Data Entry" },
    { 0x07, "Main Volume" },
    { 0x08, "Balance" },
    { 0x0A, "Panpot" },
    { 0x0B, "Expression" },
    { 0x0C, "Effect1" },
    { 0x0D, "Effect2" },
    { 0x10, "General Purpose 1" },
    { 0x11, "General Purpose 2" },
    { 0x12, "General Purpose 3" },
    { 0x13, "General Purpose 4" },
    { 0x20, "Bank Selection" },
    { 0x21, "Modulation" },
    { 0x22, "Breath" },
    { 0x24, "Foot" },
    { 0x25, "Portamento Time" },
    { 0x26, "Data Entry" },
    { 0x27, "Main Volume" },
    { 0x28, "Balance" },
    { 0x2A, "Panpot" },
    { 0x2B, "Expression" },
    { 0x2C, "Effect1" },
    { 0x2D, "Effect2" },
    { 0x30, "General Purpose 1" },
    { 0x31, "General Purpose 2" },
    { 0x32, "General Purpose 3" },
    { 0x33, "General Purpose 4" },
    { 0x40, "Sustain Pedal" },
    { 0x41, "Portamento" },
    { 0x42, "Sostenuto" },
    { 0x43, "Soft Pedal" },
    { 0x44, "Legato Foot Switch" },
    { 0x45, "Hold2" },
    { 0x46, "SC1 Sound Variation" },
    { 0x47, "SC2 Timbre" },
    { 0x48, "SC3 Release Time" },
    { 0x49, "SC4 Attack Time" },
    { 0x4A, "SC5 Brightness" },
    { 0x4B, "SC6" },
    { 0x4C, "SC7" },
    { 0x4D, "SC8" },
    { 0x4E, "SC9" },
    { 0x4F, "SC10" },
    { 0x50, "General Purpose 5" },
    { 0x51, "General Purpose 6" },
    { 0x52, "General Purpose 7" },
    { 0x53, "General Purpose 8" },
    { 0x54, "Portamento Control" },
    { 0x5B, "E1 Reverb Depth" },
    { 0x5C, "E2 Tremolo Depth" },
    { 0x5D, "E3 Chorus Depth" },
    { 0x5E, "E4 Detune Depth" },
    { 0x5F, "E5 Phaser Depth" },
    { 0x60, "Data Increment" },
    { 0x61, "Data Decrement" },
    { 0x62, "Non-registered Parameter Number" },
    { 0x63, "Non-registered Parameter Number" },
    { 0x64, "Registered Parameter Number" },
    { 0x65, "Registered Parameter Number" },
    { 0x78, "All Sounds Off" },
    { 0x79, "Reset Controllers" },
    { 0x7A, "Local Control Switch" },
    { 0x7B, "All Notes Off" },
    { 0x7C, "Omni Off" },
    { 0x7D, "Omni On" },
    { 0x7E, "Mono1" },
    { 0x7F, "Mono2" },

    { 0, NULL }
};
static value_string_ext MIDI_control_ext = VALUE_STRING_EXT_INIT(MIDI_control);

static const char *immediate_fmt = "%s";
static const char *immediate_str = "Immediate";
static const char *bundle_str = "#bundle";

/* Preference */
static guint global_osc_tcp_port = 0;

/* Initialize the protocol and registered fields */
static dissector_handle_t osc_udp_handle = NULL;

static int proto_osc = -1;

static int hf_osc_bundle_type = -1;
static int hf_osc_message_type = -1;
static int hf_osc_message_header_type = -1;
static int hf_osc_message_blob_type = -1;
static int hf_osc_message_midi_type = -1;
static int hf_osc_message_rgba_type = -1;

static int hf_osc_bundle_timetag_type = -1;
static int hf_osc_bundle_element_size_type = -1;

static int hf_osc_message_path_type = -1;
static int hf_osc_message_format_type = -1;

static int hf_osc_message_int32_type = -1;
static int hf_osc_message_float_type = -1;
static int hf_osc_message_string_type = -1;
static int hf_osc_message_blob_size_type = -1;
static int hf_osc_message_blob_data_type = -1;

static int hf_osc_message_true_type = -1;
static int hf_osc_message_false_type = -1;
static int hf_osc_message_nil_type = -1;
static int hf_osc_message_bang_type = -1;

static int hf_osc_message_int64_type = -1;
static int hf_osc_message_double_type = -1;
static int hf_osc_message_timetag_type = -1;

static int hf_osc_message_symbol_type = -1;
static int hf_osc_message_char_type = -1;

static int hf_osc_message_rgba_red_type = -1;
static int hf_osc_message_rgba_green_type = -1;
static int hf_osc_message_rgba_blue_type = -1;
static int hf_osc_message_rgba_alpha_type = -1;

static int hf_osc_message_midi_channel_type = -1;
static int hf_osc_message_midi_status_type = -1;
static int hf_osc_message_midi_data1_type = -1;
static int hf_osc_message_midi_data2_type = -1;
static int hf_osc_message_midi_controller_type = -1;
static int hf_osc_message_midi_value_type = -1;

/* Initialize the subtree pointers */
static int ett_osc_packet = -1;
static int ett_osc_bundle = -1;
static int ett_osc_message = -1;
static int ett_osc_message_header = -1;
static int ett_osc_blob = -1;
static int ett_osc_rgba = -1;
static int ett_osc_midi = -1;

/* check for valid path string */
static gboolean
is_valid_path(const char *path)
{
    const char *ptr;
    if(path[0] != '/')
        return FALSE;
    for(ptr=path+1; *ptr!='\0'; ptr++)
        if( (g_ascii_isprint(*ptr) == 0) || (strchr(invalid_path_chars, *ptr) != NULL) )
            return FALSE;
    return TRUE;
}

/* check for valid format string */
static gboolean
is_valid_format(const char *format)
{
    const char *ptr;
    if(format[0] != ',')
        return FALSE;
    for(ptr=format+1; *ptr!='\0'; ptr++)
        if(strchr(valid_format_chars, *ptr) == NULL)
            return FALSE;
    return TRUE;
}

/* Dissect OSC message */
static int
dissect_osc_message(tvbuff_t *tvb, proto_item *ti, proto_tree *osc_tree, gint offset, gint len)
{
    proto_tree  *message_tree;
    proto_tree  *header_tree;
    gint         slen;
    gint         rem;
    gint         end = offset + len;
    const gchar *path;
    gint         path_len;
    gint         path_offset;
    const gchar *format;
    gint         format_offset;
    gint         format_len;
    const gchar *ptr;

    /* peek/read path */
    path_offset = offset;
    path = tvb_get_const_stringz(tvb, path_offset, &path_len);
    if( (rem = path_len%4) ) path_len += 4-rem;

    if(!is_valid_path(path))
        return -1;

    /* peek/read fmt */
    format_offset = path_offset + path_len;
    format = tvb_get_const_stringz(tvb, format_offset, &format_len);
    if( (rem = format_len%4) ) format_len += 4-rem;

    if(!is_valid_format(format))
        return -1;

    /* create message */
    ti = proto_tree_add_none_format(osc_tree, hf_osc_message_type, tvb, offset, len, "Message: %s %s", path, format);
    message_tree = proto_item_add_subtree(ti, ett_osc_message);

    /* append header */
    ti = proto_tree_add_item(message_tree, hf_osc_message_header_type, tvb, offset, path_len+format_len, ENC_NA);
    header_tree = proto_item_add_subtree(ti, ett_osc_message_header);

    /* append path */
    proto_tree_add_item(header_tree, hf_osc_message_path_type, tvb, path_offset, path_len, ENC_ASCII | ENC_NA);

    /* append format */
    proto_tree_add_item(header_tree, hf_osc_message_format_type, tvb, format_offset, format_len, ENC_ASCII | ENC_NA);

    offset += path_len + format_len;

    /* ::parse argument:: */
    ptr = format + 1; /* skip ',' */
    while( (*ptr != '\0') && (offset < end) )
    {
        switch(*ptr)
        {
            case OSC_INT32:
                proto_tree_add_item(message_tree, hf_osc_message_int32_type, tvb, offset, 4, ENC_BIG_ENDIAN);
                offset += 4;
                break;
            case OSC_FLOAT:
                proto_tree_add_item(message_tree, hf_osc_message_float_type, tvb, offset, 4, ENC_BIG_ENDIAN);
                offset += 4;
                break;
            case OSC_STRING:
                slen = tvb_strsize(tvb, offset);
                if( (rem = slen%4) ) slen += 4-rem;
                proto_tree_add_item(message_tree, hf_osc_message_string_type, tvb, offset, slen, ENC_ASCII | ENC_NA);
                offset += slen;
                break;
            case OSC_BLOB:
            {
                proto_item *bi;
                proto_tree *blob_tree;

                gint32 blen = tvb_get_ntohl(tvb, offset);
                slen = blen;
                if( (rem = slen%4) ) slen += 4-rem;

                bi = proto_tree_add_none_format(message_tree, hf_osc_message_blob_type, tvb, offset, 4+slen, "Blob: %i bytes", blen);
                blob_tree = proto_item_add_subtree(bi, ett_osc_blob);

                proto_tree_add_int_format_value(blob_tree, hf_osc_message_blob_size_type, tvb, offset, 4, blen, "%i bytes", blen);
                offset += 4;

                /* check for zero length blob */
                if(blen == 0)
                    break;

                proto_tree_add_item(blob_tree, hf_osc_message_blob_data_type, tvb, offset, slen, ENC_NA);
                offset += slen;
                break;
            }

            case OSC_TRUE:
                proto_tree_add_item(message_tree, hf_osc_message_true_type, tvb, offset, 0, ENC_NA);
                break;
            case OSC_FALSE:
                proto_tree_add_item(message_tree, hf_osc_message_false_type, tvb, offset, 0, ENC_NA);
                break;
            case OSC_NIL:
                proto_tree_add_item(message_tree, hf_osc_message_nil_type, tvb, offset, 0, ENC_NA);
                break;
            case OSC_BANG:
                proto_tree_add_item(message_tree, hf_osc_message_bang_type, tvb, offset, 0, ENC_NA);
                break;

            case OSC_INT64:
                proto_tree_add_item(message_tree, hf_osc_message_int64_type, tvb, offset, 8, ENC_BIG_ENDIAN);
                offset += 8;
                break;
            case OSC_DOUBLE:
                proto_tree_add_item(message_tree, hf_osc_message_double_type, tvb, offset, 8, ENC_BIG_ENDIAN);
                offset += 8;
                break;
            case OSC_TIMETAG:
            {
                guint32  sec  = tvb_get_ntohl(tvb, offset);
                guint32  frac = tvb_get_ntohl(tvb, offset+4);
                nstime_t ns;
                if( (sec == 0) && (frac == 1) )
                    proto_tree_add_time_format_value(message_tree, hf_osc_message_timetag_type, tvb, offset, 8, &ns, immediate_fmt, immediate_str);
                else
                    proto_tree_add_item(message_tree, hf_osc_message_timetag_type, tvb, offset, 8, ENC_TIME_NTP | ENC_BIG_ENDIAN);
                offset += 8;
            }
                break;

            case OSC_SYMBOL:
                slen = tvb_strsize(tvb, offset);
                if( (rem = slen%4) ) slen += 4-rem;
                proto_tree_add_item(message_tree, hf_osc_message_symbol_type, tvb, offset, slen, ENC_ASCII | ENC_NA);
                offset += slen;
                break;
            case OSC_CHAR:
                offset += 3;
                proto_tree_add_item(message_tree, hf_osc_message_char_type, tvb, offset, 1, ENC_ASCII | ENC_NA);
                offset += 1;
                break;
            case OSC_RGBA:
            {
                proto_item *ri;
                proto_tree *rgba_tree;

                ri = proto_tree_add_item(message_tree, hf_osc_message_rgba_type, tvb, offset, 4, ENC_BIG_ENDIAN);
                rgba_tree = proto_item_add_subtree(ri, ett_osc_rgba);

                proto_tree_add_item(rgba_tree, hf_osc_message_rgba_red_type, tvb, offset, 1, ENC_BIG_ENDIAN);
                offset += 1;
                proto_tree_add_item(rgba_tree, hf_osc_message_rgba_green_type, tvb, offset, 1, ENC_BIG_ENDIAN);
                offset += 1;
                proto_tree_add_item(rgba_tree, hf_osc_message_rgba_blue_type, tvb, offset, 1, ENC_BIG_ENDIAN);
                offset += 1;
                proto_tree_add_item(rgba_tree, hf_osc_message_rgba_alpha_type, tvb, offset, 1, ENC_BIG_ENDIAN);
                offset += 1;
                break;
            }
            case OSC_MIDI:
            {
                const gchar *status_str;
                proto_item  *mi = NULL;
                proto_tree  *midi_tree;
                guint8       channel;
                guint8       status;
                guint8       data1;
                guint8       data2;

                channel = tvb_get_guint8(tvb, offset);
                status  = tvb_get_guint8(tvb, offset+1);
                data1   = tvb_get_guint8(tvb, offset+2);
                data2   = tvb_get_guint8(tvb, offset+3);

                status_str = val_to_str_ext_const(status, &MIDI_status_ext, "Unknown");

                if(status == MIDI_STATUS_CONTROLLER) /* MIDI Controller */
                {
                    const gchar *control_str;
                    control_str = val_to_str_ext_const(data1, &MIDI_control_ext, "Unknown");

                    mi = proto_tree_add_none_format(message_tree, hf_osc_message_midi_type, tvb, offset, 4,
                            "MIDI: Channel %2i, %s (0x%02x), %s (0x%02x), 0x%02x",
                            channel,
                            status_str, status,
                            control_str, data1,
                            data2);
                }
                else
                {
                    mi = proto_tree_add_none_format(message_tree, hf_osc_message_midi_type, tvb, offset, 4,
                            "MIDI: Channel %2i, %s (0x%02x), 0x%02x, 0x%02x",
                            channel,
                            status_str, status,
                            data1, data2);
                }
                midi_tree = proto_item_add_subtree(mi, ett_osc_midi);

                proto_tree_add_item(midi_tree, hf_osc_message_midi_channel_type, tvb, offset, 1, ENC_BIG_ENDIAN);
                offset += 1;

                proto_tree_add_item(midi_tree, hf_osc_message_midi_status_type, tvb, offset, 1, ENC_BIG_ENDIAN);
                offset += 1;

                if(status == MIDI_STATUS_CONTROLLER)
                {
                    proto_tree_add_item(midi_tree, hf_osc_message_midi_controller_type, tvb, offset, 1, ENC_BIG_ENDIAN);
                    offset += 1;

                    proto_tree_add_item(midi_tree, hf_osc_message_midi_value_type, tvb, offset, 1, ENC_BIG_ENDIAN);
                    offset += 1;
                }
                else
                {
                    proto_tree_add_item(midi_tree, hf_osc_message_midi_data1_type, tvb, offset, 1, ENC_BIG_ENDIAN);
                    offset += 1;

                    proto_tree_add_item(midi_tree, hf_osc_message_midi_data2_type, tvb, offset, 1, ENC_BIG_ENDIAN);
                    offset += 1;
                }

                break;
            }

            default:
                /* if we get here, there must be a bug in the dissector  */
                DISSECTOR_ASSERT_NOT_REACHED();
                break;
        }
        ptr++;
    }

    if(offset != end)
        return -1;
    else
        return 0;
}

/* Dissect OSC bundle */
static int
dissect_osc_bundle(tvbuff_t *tvb, proto_item *ti, proto_tree *osc_tree, gint offset, gint len)
{
    proto_tree  *bundle_tree;
    gint         end = offset + len;
    guint32      sec;
    guint32      frac;
    nstime_t     ns;

    /* check for valid #bundle */
    if(tvb_strneql(tvb, offset, bundle_str, 8) != 0)
        return -1;

    /* create bundle */
    ti = proto_tree_add_item(osc_tree, hf_osc_bundle_type, tvb, offset, len, ENC_NA);

    bundle_tree = proto_item_add_subtree(ti, ett_osc_bundle);

    offset += 8; /* skip bundle_str */

    /* read timetag */
    sec  = tvb_get_ntohl(tvb, offset);
    frac = tvb_get_ntohl(tvb, offset+4);
    if( (sec == 0) && (frac == 1) )
        proto_tree_add_time_format_value(bundle_tree, hf_osc_bundle_timetag_type, tvb, offset, 8, &ns, immediate_fmt, immediate_str);
    else
        proto_tree_add_item(bundle_tree, hf_osc_bundle_timetag_type, tvb, offset, 8, ENC_TIME_NTP | ENC_BIG_ENDIAN);
    offset += 8;

    /* ::read size, read block:: */
    while(offset < end)
    {
        /* peek bundle element size */
        gint32 size = tvb_get_ntohl(tvb, offset);

        /* read bundle element size */
        proto_tree_add_int_format_value(bundle_tree, hf_osc_bundle_element_size_type, tvb, offset, 4, size, "%i bytes", size);
        offset += 4;

        /* check for zero size bundle element */
        if(size == 0)
            continue;

        /* peek first bundle element char */
        switch(tvb_get_guint8(tvb, offset))
        {
            case '#': /* this is a bundle */
                if(dissect_osc_bundle(tvb, ti, bundle_tree, offset, size))
                    return -1;
                else
                    break;
            case '/': /* this is a message */
                if(dissect_osc_message(tvb, ti, bundle_tree, offset, size))
                    return -1;
                else
                    break;
            default:
                return -1; /* neither message nor bundle */
        }

        /* check for integer overflow */
        if(size > G_MAXINT - offset)
            return -1;
        else
            offset += size;
    }

    if(offset != end)
        return -1;
    else
        return 0;
}

/* Dissect OSC PDU */
static void
dissect_osc_pdu_common(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_, gint offset, gint len)
{
    col_set_str(pinfo->cinfo, COL_PROTOCOL, "OSC");
    col_clear(pinfo->cinfo, COL_INFO);

    if(tree) /* we are being asked for details */
    {
        proto_item *ti;
        proto_tree *osc_tree;

        /* create OSC packet */
        ti = proto_tree_add_item(tree, proto_osc, tvb, 0, -1, ENC_NA);
        osc_tree = proto_item_add_subtree(ti, ett_osc_packet);

        /* peek first bundle element char */
        switch(tvb_get_guint8(tvb, offset))
        {
            case '#': /* this is a bundle */
                if(dissect_osc_bundle(tvb, ti, osc_tree, offset, len))
                    return;
                else
                    break;
            case '/': /* this is a message */
                if(dissect_osc_message(tvb, ti, osc_tree, offset, len))
                    return;
                else
                    break;
            default: /* neither message nor bundle */
                return;
        }
    }
}

/* OSC TCP */

static guint
get_osc_pdu_len(packet_info *pinfo _U_, tvbuff_t *tvb, int offset, void *data _U_)
{
    return tvb_get_ntohl(tvb, offset) + 4;
}

static int
dissect_osc_tcp_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
{
    gint pdu_len;

    pdu_len = tvb_get_ntohl(tvb, 0);
    dissect_osc_pdu_common(tvb, pinfo, tree, data, 4, pdu_len);
    return pdu_len;
}

static int
dissect_osc_tcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
{
    tcp_dissect_pdus(tvb, pinfo, tree, TRUE, 4, get_osc_pdu_len,
                     dissect_osc_tcp_pdu, data);
    return tvb_reported_length(tvb);
}

/* OSC UDP */

static int
dissect_osc_udp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
{
    gint pdu_len;

    pdu_len = tvb_reported_length(tvb);
    dissect_osc_pdu_common(tvb,pinfo, tree, data, 0, pdu_len);
    return pdu_len;
}

/* UDP Heuristic */
static gboolean
dissect_osc_heur_udp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
{
    conversation_t *conversation;

    if(tvb_captured_length(tvb) < 8)
        return FALSE;

    /* peek first string */
    if(tvb_strneql(tvb, 0, bundle_str, 8) != 0) /* no OSC bundle */
    {
        gint               offset = 0;
        gint               slen;
        gint               rem;
        const gchar       *str;
        volatile gboolean  valid  = FALSE;

        /* Check for valid path */
        /* Don't propagate any exceptions upwards during heuristics check  */
        /* XXX: this check is a bit expensive; Consider: use UDP port pref ? */
        TRY {
            str = tvb_get_const_stringz(tvb, offset, &slen);
            if(is_valid_path(str)) {

                /* skip path */
                if( (rem = slen%4) ) slen += 4-rem;
                offset += slen;

                /* peek next string */
                str = tvb_get_const_stringz(tvb, offset, &slen);

                /* check for valid format */
                if(is_valid_format(str))
                    valid = TRUE;
            }
        }
        CATCH_ALL {
            valid = FALSE;
        }
        ENDTRY;

        if(! valid)
            return FALSE;
    }

    /* if we get here, then it's an Open Sound Control packet (bundle or message) */

    /* specify that dissect_osc is to be called directly from now on for packets for this connection */
    conversation = find_or_create_conversation(pinfo);
    conversation_set_dissector(conversation, osc_udp_handle);

    /* do the dissection */
    dissect_osc_udp(tvb, pinfo, tree, data);

    return TRUE; /* OSC heuristics was matched */
}

/* Register the protocol with Wireshark */
void
proto_register_osc(void)
{
    static hf_register_info hf[] = {
        { &hf_osc_bundle_type, { "Bundle", "osc.bundle",
                FT_NONE, BASE_NONE,
                NULL, 0x0,
                "Bundle structure", HFILL } },
        { &hf_osc_bundle_timetag_type, { "Timetag", "osc.bundle.timetag",
                FT_ABSOLUTE_TIME, ABSOLUTE_TIME_UTC,
                NULL, 0x0,
                "Scheduled bundle execution time", HFILL } },

        { &hf_osc_bundle_element_size_type, { "Size", "osc.bundle.element.size",
                FT_INT32, BASE_DEC,
                NULL, 0x0,
                "Bundle element size", HFILL } },

        { &hf_osc_message_type, { "Message", "osc.message",
                FT_NONE, BASE_NONE,
                NULL, 0x0,
                "Message structure", HFILL } },
        { &hf_osc_message_header_type, { "Header", "osc.message.header",
                FT_NONE, BASE_NONE,
                NULL, 0x0,
                "Message header", HFILL } },
        { &hf_osc_message_path_type, { "Path", "osc.message.header.path",
                FT_STRING, BASE_NONE,
                NULL, 0x0,
                "Message path", HFILL } },
        { &hf_osc_message_format_type, { "Format", "osc.message.header.format",
                FT_STRING, BASE_NONE,
                NULL, 0x0,
                "Message format", HFILL } },

        { &hf_osc_message_int32_type, { "Int32", "osc.message.int32",
                FT_INT32, BASE_DEC,
                NULL, 0x0,
                "32bit integer value", HFILL } },
        { &hf_osc_message_float_type, { "Float", "osc.message.float",
                FT_FLOAT, BASE_NONE,
                NULL, 0x0,
                "Floating point value", HFILL } },
        { &hf_osc_message_string_type, { "String", "osc.message.string",
                FT_STRING, BASE_NONE,
                NULL, 0x0,
                "String value", HFILL } },

        { &hf_osc_message_blob_type, { "Blob", "osc.message.blob",
                FT_NONE, BASE_NONE,
                NULL, 0x0,
                "Binary blob value", HFILL } },
        { &hf_osc_message_blob_size_type, { "Size", "osc.message.blob.size",
                FT_INT32, BASE_DEC,
                NULL, 0x0,
                "Binary blob size", HFILL } },
        { &hf_osc_message_blob_data_type, { "Data", "osc.message.blob.data",
                FT_BYTES, BASE_NONE,
                NULL, 0x0,
                "Binary blob data", HFILL } },

        { &hf_osc_message_true_type, { "True", "osc.message.true",
                FT_NONE, BASE_NONE,
                NULL, 0x0,
                "Boolean true value", HFILL } },
        { &hf_osc_message_false_type, { "False", "osc.message.false",
                FT_NONE, BASE_NONE,
                NULL, 0x0,
                "Boolean false value", HFILL } },
        { &hf_osc_message_nil_type, { "Nil", "osc.message.nil",
                FT_NONE, BASE_NONE,
                NULL, 0x0,
                "Nil value", HFILL } },
        { &hf_osc_message_bang_type, { "Bang", "osc.message.bang",
                FT_NONE, BASE_NONE,
                NULL, 0x0,
                "Infinity, Impulse or Bang value", HFILL } },

        { &hf_osc_message_int64_type, { "Int64", "osc.message.int64",
                FT_INT64, BASE_DEC,
                NULL, 0x0,
                "64bit integer value", HFILL } },
        { &hf_osc_message_double_type, { "Double", "osc.message.double",
                FT_DOUBLE, BASE_NONE,
                NULL, 0x0,
                "Double value", HFILL } },
        { &hf_osc_message_timetag_type, { "Timetag", "osc.message.timetag",
                FT_ABSOLUTE_TIME, ABSOLUTE_TIME_UTC,
                NULL, 0x0,
                "NTP time value", HFILL } },

        { &hf_osc_message_symbol_type, { "Symbol", "osc.message.symbol",
                FT_STRING, BASE_NONE,
                NULL, 0x0,
                "Symbol value", HFILL } },
        { &hf_osc_message_char_type, { "Char", "osc.message.char",
                FT_STRING, BASE_NONE,
                NULL, 0x0,
                "Character value", HFILL } },

        { &hf_osc_message_rgba_type, { "RGBA", "osc.message.rgba",
                FT_UINT32, BASE_HEX,
                NULL, 0x0,
                "RGBA color value", HFILL } },
        { &hf_osc_message_rgba_red_type, { "Red", "osc.message.rgba.red",
                FT_UINT8, BASE_DEC,
                NULL, 0x0,
                "Red color component", HFILL } },
        { &hf_osc_message_rgba_green_type, { "Green", "osc.message.rgba.green",
                FT_UINT8, BASE_DEC,
                NULL, 0x0,
                "Green color component", HFILL } },
        { &hf_osc_message_rgba_blue_type, { "Blue", "osc.message.rgba.blue",
                FT_UINT8, BASE_DEC,
                NULL, 0x0,
                "Blue color component", HFILL } },
        { &hf_osc_message_rgba_alpha_type, { "Alpha", "osc.message.rgba.alpha",
                FT_UINT8, BASE_DEC,
                NULL, 0x0,
                "Alpha transparency component", HFILL } },

        { &hf_osc_message_midi_type, { "MIDI", "osc.message.midi",
                FT_NONE, BASE_NONE,
                NULL, 0x0,
                "MIDI value", HFILL } },
        { &hf_osc_message_midi_channel_type, { "Channel", "osc.message.midi.channel",
                FT_UINT8, BASE_DEC,
                NULL, 0x0,
                "MIDI channel", HFILL } },
        { &hf_osc_message_midi_status_type, { "Status", "osc.message.midi.status",
                FT_UINT8, BASE_HEX | BASE_EXT_STRING,
                &MIDI_status_ext, 0x0,
                "MIDI status message", HFILL } },
        { &hf_osc_message_midi_data1_type, { "Data1", "osc.message.midi.data1",
                FT_UINT8, BASE_HEX,
                NULL, 0x0,
                "MIDI data value 1", HFILL } },
        { &hf_osc_message_midi_data2_type, { "Data2", "osc.message.midi.data2",
                FT_UINT8, BASE_HEX,
                NULL, 0x0,
                "MIDI data value 2", HFILL } },
        { &hf_osc_message_midi_controller_type, { "Controller", "osc.message.midi.controller",
                FT_UINT8, BASE_HEX | BASE_EXT_STRING,
                &MIDI_control_ext, 0x0,
                "MIDI controller message", HFILL } },
        { &hf_osc_message_midi_value_type, { "Value", "osc.message.midi.value",
                FT_UINT8, BASE_HEX,
                NULL, 0x0,
                "MIDI controller value", HFILL } }
    };

    /* Setup protocol subtree array */
    static gint *ett[] = {
        &ett_osc_packet,
        &ett_osc_bundle,
        &ett_osc_message,
        &ett_osc_message_header,
        &ett_osc_blob,
        &ett_osc_rgba,
        &ett_osc_midi
    };

    module_t *osc_module;

    proto_osc = proto_register_protocol("Open Sound Control Protocol", "OSC", "osc");

    proto_register_field_array(proto_osc, hf, array_length(hf));
    proto_register_subtree_array(ett, array_length(ett));

    osc_module = prefs_register_protocol(proto_osc, proto_reg_handoff_osc);

    prefs_register_uint_preference(osc_module, "tcp.port",
                                   "OSC TCP Port",
                                   "Set the TCP port for OSC",
                                   10, &global_osc_tcp_port);
}

void
proto_reg_handoff_osc(void)
{
    static dissector_handle_t osc_tcp_handle;
    static guint              osc_tcp_port;
    static gboolean           initialized = FALSE;

    if(! initialized)
    {
        osc_tcp_handle = create_dissector_handle(dissect_osc_tcp, proto_osc);
        /* register for "decode as" for TCP connections */
        dissector_add_for_decode_as("tcp.port", osc_tcp_handle);

        /* XXX: Add port pref and  "decode as" for UDP ? */
        /*      (The UDP heuristic is a bit expensive    */
        osc_udp_handle = create_dissector_handle(dissect_osc_udp, proto_osc);
        /* register as heuristic dissector for UDP connections */
        heur_dissector_add("udp", dissect_osc_heur_udp, "Open Sound Control over UDP", "osc_udp", proto_osc, HEURISTIC_ENABLE);

        initialized = TRUE;
    }
    else
    {
        if(osc_tcp_port != 0)
            dissector_delete_uint("tcp.port", osc_tcp_port, osc_tcp_handle);
    }

    osc_tcp_port = global_osc_tcp_port;
    if(osc_tcp_port != 0)
        dissector_add_uint("tcp.port", osc_tcp_port, osc_tcp_handle);
}

/*
 * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
 *
 * Local variables:
 * c-basic-offset: 4
 * tab-width: 8
 * indent-tabs-mode: nil
 * End:
 *
 * vi: set shiftwidth=4 tabstop=8 expandtab:
 * :indentSize=4:tabSize=8:noTabs=true:
 */