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

/* packet-daap.c
 * Routines for Digital Audio Access Protocol dissection
 * Copyright 2004, Kelly Byrd <kbyrd@memcpy.com>
 *
 * 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.
 */

#include "config.h"

#include <glib.h>
#include <epan/packet.h>
#include <epan/exceptions.h>
#include <epan/dissectors/packet-http.h>

#define TCP_PORT_DAAP 3689

/* DAAP tags */
/* Some information taken from http://tapjam.net/daap/ */
/* and http://www.deleet.de/projekte/daap/?ContentCodes */
/* DACP tags */
/* Information from http://dacp.jsharkey.org/ */
/* and http://code.google.com/p/tunesremote-plus/ */

/* Container tags */
#define daap_mcon       0x6d636f6e
#define daap_msrv       0x6d737276
#define daap_mccr       0x6d636372
#define daap_mdcl       0x6d64636c
#define daap_mlog       0x6d6c6f67
#define daap_mupd       0x6d757064
#define daap_avdb       0x61766462
#define daap_mlcl       0x6d6c636c
#define daap_mlit       0x6d6c6974
#define daap_mbcl       0x6d62636c
#define daap_adbs       0x61646273
#define daap_aply       0x61706c79
#define daap_apso       0x6170736f
#define daap_mudl       0x6d75646c
#define daap_abro       0x6162726f
#define daap_abar       0x61626172
#define daap_arsv       0x61727376
#define daap_abal       0x6162616c
#define daap_abcp       0x61626370
#define daap_abgn       0x6162676e
#define daap_prsv       0x70727376
#define daap_arif       0x61726966
#define daap_mctc       0x6d637463
#define dacp_casp       0x63617370
#define dacp_cmst       0x636d7374
#define dacp_cmgt       0x636d6774
/* String tags */
#define daap_minm       0x6d696e6d
#define daap_msts       0x6d737473
#define daap_mcnm       0x6d636e6d
#define daap_mcna       0x6d636e61
#define daap_asal       0x6173616c
#define daap_asar       0x61736172
#define daap_ascm       0x6173636d
#define daap_asfm       0x6173666d
#define daap_aseq       0x61736571
#define daap_asgn       0x6173676e
#define daap_asdt       0x61736474
#define daap_asul       0x6173756c
#define daap_ascp       0x61736370
#define daap_asct       0x61736374
#define daap_ascn       0x6173636e
#define daap_aslc       0x61736c63
#define daap_asky       0x61736b79
#define daap_aeSN       0x6165534e
#define daap_aeNN       0x61654e4e
#define daap_aeEN       0x6165454e
#define daap_assn       0x6173736e
#define daap_assa       0x61737361
#define daap_assl       0x6173736c
#define daap_assc       0x61737363
#define daap_asss       0x61737373
#define daap_asaa       0x61736161
#define daap_aspu       0x61737075
#define daap_aeCR       0x61654352
#define dacp_cana       0x63616e61
#define dacp_cang       0x63616e67
#define dacp_canl       0x63616e6c
#define dacp_cann       0x63616e6e

/* uint64 tags */
#define daap_mper       0x6d706572
#define daap_aeGU       0x61654755
#define daap_aeGR       0x61654752
#define daap_asai       0x61736169
#define daap_asls       0x61736c73

/* uint32 tags */
#define daap_mstt       0x6d737474
#define daap_musr       0x6d757372
#define daap_miid       0x6d696964
#define daap_mcti       0x6d637469
#define daap_mpco       0x6d70636f
#define daap_mimc       0x6d696d63
#define daap_mrco       0x6d72636f
#define daap_mtco       0x6d74636f
#define daap_mstm       0x6d73746d
#define daap_msdc       0x6d736463
#define daap_mlid       0x6d6c6964
#define daap_msur       0x6d737572
#define daap_asda       0x61736461
#define daap_asdm       0x6173646d
#define daap_assr       0x61737372
#define daap_assz       0x6173737a
#define daap_asst       0x61737374
#define daap_assp       0x61737370
#define daap_astm       0x6173746d
#define daap_aeNV       0x61654e56
#define daap_ascd       0x61736364
#define daap_ascs       0x61736373
#define daap_aeSV       0x61655356
#define daap_aePI       0x61655049
#define daap_aeCI       0x61654349
#define daap_aeGI       0x61654749
#define daap_aeAI       0x61654149
#define daap_aeSI       0x61655349
#define daap_aeES       0x61654553
#define daap_aeSU       0x61655355
#define daap_asbo       0x6173626f
#define daap_aeGH       0x61654748
#define daap_aeGD       0x61654744
#define daap_aeGE       0x61654745
#define daap_meds       0x6d656473
#define dacp_cmsr       0x636d7372
#define dacp_cant       0x63616e74
#define dacp_cast       0x63617374
#define dacp_cmvo       0x636d766f
/*TODO:
#define daap_msto               0x6d7374OO utcoffset
*/
/* uint16 tags */
#define daap_mcty       0x6d637479
#define daap_asbt       0x61736274
#define daap_asbr       0x61736272
#define daap_asdc       0x61736463
#define daap_asdn       0x6173646e
#define daap_astc       0x61737463
#define daap_astn       0x6173746e
#define daap_asyr       0x61737972
#define daap_ased       0x61736564
/* byte  tags */
#define daap_mikd       0x6d696b64
#define daap_msau       0x6d736175
#define daap_msty       0x6d737479
#define daap_asrv       0x61737276 /* XXX: may be uint16 in newer iTunes versions! */
#define daap_asur       0x61737572
#define daap_asdk       0x6173646b
#define daap_muty       0x6d757479
#define daap_msas       0x6d736173
#define daap_aeHV       0x61654856
#define daap_aeHD       0x61654844
#define daap_aePC       0x61655043
#define daap_aePP       0x61655050
#define daap_aeMK       0x61654d4b
#define daap_aeSG       0x61655347
#define daap_apsm       0x6170736d
#define daap_aprm       0x6170726d
#define daap_asgp       0x61736770
#define daap_aePS       0x61655053
#define daap_asbk       0x6173626b
#define dacp_cafs       0x63616673
#define dacp_caps       0x63617073
#define dacp_carp       0x63617270
#define dacp_cash       0x63617368
#define dacp_cavs       0x63617673
/* boolean  tags */
#define daap_mslr       0x6d736c72
#define daap_msal       0x6d73616c
#define daap_msup       0x6d737570
#define daap_mspi       0x6d737069
#define daap_msex       0x6d736578
#define daap_msbr       0x6d736272
#define daap_msqy       0x6d737179
#define daap_msix       0x6d736978
#define daap_msrs       0x6d737273
#define daap_asco       0x6173636f
#define daap_asdb       0x61736462
#define daap_abpl       0x6162706c
#define daap_aeSP       0x61655350
#define daap_ashp       0x61736870
/* version (32-bit)*/
#define daap_mpro       0x6d70726f
#define daap_apro       0x6170726f
/* now playing */
#define dacp_canp       0x63616e70

#define daap_png        0x89504e47
/* date/time */
/* TODO:
#define daap_mstc 0xMMSSTTCC utctime
#define daap_asdr ("daap.songdatereleased")
#define daap_asdp ("daap.songdatepurchased")
*/

void proto_register_daap(void);
void proto_reg_handoff_daap(void);

static dissector_handle_t png_handle;

/*XXX: Sorted by value definition since it appears that the "value" is just */
/*     the ascii representation of the last 4 letters of the definition.    */
/*     (Sorted so a binary search can be done when using value_string_ext)  */
static const value_string vals_tag_code[] = {
   { daap_abal, "browse album listing" },
   { daap_abar, "browse artist listing" },
   { daap_abcp, "browse composer listing" },
   { daap_abgn, "browse genre listing" },
   { daap_abpl, "base playlist" },
   { daap_abro, "database browse" },
   { daap_adbs, "database songs" },
   { daap_aeAI, "com.apple.itunes.itms-artistid" },
   { daap_aeCI, "com.apple.itunes.itms-composerid" },
   { daap_aeCR, "com.apple.itunes.content-rating" },
   { daap_aeEN, "com.apple.itunes.episode-num-str" },
   { daap_aeES, "com.apple.itunes.episode-sort" },
   { daap_aeGD, "com.apple.itunes.gapless-enc-dr" },
   { daap_aeGE, "com.apple.itunes.gapless-enc-del" },
   { daap_aeGH, "com.apple.itunes.gapless-heur" },
   { daap_aeGI, "com.apple.itunes.itms-genreid" },
   { daap_aeGR, "com.apple.itunes.gapless-resy" },
   { daap_aeGU, "com.apple.itunes.gapless-dur" },
   { daap_aeHD, "com.apple.itunes.is-hd-video" },
   { daap_aeHV, "com.apple.itunes.has-video" },
   { daap_aeMK, "com.apple.itunes.mediakind" },
   { daap_aeNN, "com.apple.itunes.network-name" },
   { daap_aeNV, "com.apple.itunes.norm-volume" },
   { daap_aePC, "com.apple.itunes.is-podcast" },
   { daap_aePI, "com.apple.itunes.itms-playlistid" },
   { daap_aePP, "com.apple.itunes.is-podcast-playlist" },
   { daap_aePS, "com.apple.itunes.special-playlist" },
   { daap_aeSG, "com.apple.itunes.saved-genius" },
   { daap_aeSI, "com.apple.itunes.itms-songid" },
   { daap_aeSN, "com.apple.itunes.series-name" },
   { daap_aeSP, "com.apple.itunes.smart-playlist" },
   { daap_aeSU, "com.apple.itunes.season-num" },
   { daap_aeSV, "com.apple.itunes.music-sharing-version" },
   { daap_aply, "database playlists" },
   { daap_aprm, "playlist repeat mode" },
   { daap_apro, "protocol (application?) version (apro)" },
   { daap_apsm, "playlist shuffle mode" },
   { daap_apso, "playlist songs" },
   { daap_arif, "resolveinfo" },
   { daap_arsv, "resolve" },
   { daap_asaa, "song album artist" },
   { daap_asai, "song album id"},
   { daap_asal, "song album" },
   { daap_asar, "song artist" },
   { daap_asbk, "song bookmarkable" },
   { daap_asbo, "song bookmark" },
   { daap_asbr, "song bitrate" },
   { daap_asbt, "song beats-per-minute" },
   { daap_ascd, "song codec type" },
   { daap_ascm, "song comment" },
   { daap_ascn, "song content description" },
   { daap_asco, "song compilation" },
   { daap_ascp, "song composer" },
   { daap_ascs, "song codec subtype" },
   { daap_asct, "song category" },
   { daap_asda, "song date added" },
   { daap_asdb, "song disabled" },
   { daap_asdc, "song disccount" },
   { daap_asdk, "song data kind" },
   { daap_asdm, "song date modified" },
   { daap_asdn, "song discnumber" },
   { daap_asdt, "song description" },
   { daap_ased, "song extra data" },
   { daap_aseq, "song eq preset" },
   { daap_asfm, "song format" },
   { daap_asgn, "song genre" },
   { daap_asgp, "song gapless" },
   { daap_ashp, "song has been played" },
   { daap_asky, "song keywords" },
   { daap_aslc, "song long content description" },
   { daap_asls, "song long size"},
   { daap_aspu, "song podcast url" },
   { daap_asrv, "song relative volume" },
   { daap_assa, "sort artist" },
   { daap_assc, "sort composer" },
   { daap_assn, "sort name" },
   { daap_assp, "song stop time (milliseconds)" },
   { daap_assr, "song sample rate" },
   { daap_asss, "sort seriesname" },
   { daap_asst, "song start time (milliseconds)" },
   { daap_assz, "song size" },
   { daap_astc, "song track count" },
   { daap_astm, "song time (milliseconds)" },
   { daap_astn, "song track number" },
   { daap_asul, "song data url" },
   { daap_asur, "song user rating" },
   { daap_asyr, "song year" },
   { daap_avdb, "server databases" },
   { dacp_cafs, "fullscreen" },
   { dacp_cana, "song artist" },
   { dacp_cang, "song genre" },
   { dacp_canl, "song album" },
   { dacp_cann, "song name" },
   { dacp_canp, "now playing" },
   { dacp_cant, "song time remaining (milliseconds)" },
   { dacp_caps, "play status" },
   { dacp_carp, "repeat" },
   { dacp_cash, "shuffle" },
   { dacp_casp, "speakers container" },
   { dacp_cast, "song time total (milliseconds)" },
   { dacp_cavs, "visualizer" },
   { dacp_cmgt, "container (cmgt)" },
   { dacp_cmsr, "status revision" },
   { dacp_cmst, "control container" },
   { dacp_cmvo, "volume" },
   { daap_mbcl, "bag (mbcl)" },
   { daap_mccr, "content codes response" },
   { daap_mcna, "content codes name" },
   { daap_mcnm, "content codes number" },
   { daap_mcon, "container (mcon)" },
   { daap_mctc, "container count" },
   { daap_mcti, "container item id (mcti)" },
   { daap_mcty, "content codes type" },
   { daap_mdcl, "dictionary (mdcl)" },
   { daap_meds, "edit commands supported" },
   { daap_miid, "item id (miid)" },
   { daap_mikd, "item kind (mikd)" },
   { daap_mimc, "item count (mimc)" },
   { daap_minm, "item name (minm)" },
   { daap_mlcl, "listing (mlcl)" },
   { daap_mlid, "session id" },
   { daap_mlit, "listing item (mlit)" },
   { daap_mlog, "login response" },
   { daap_mpco, "parent container id (mpco)" },
   { daap_mper, "persistent id (mper)" },
   { daap_mpro, "protocol version (mpro)" },
   { daap_mrco, "returned count (mrco)" },
   { daap_msal, "supports auto-logout (msal)" },
   { daap_msas, "authentication schemes" },
   { daap_msau, "authentication method (msau)" },
   { daap_msbr, "supports browse" },
   { daap_msdc, "databases count" },
   { daap_msex, "supports extensions (msex)" },
   { daap_msix, "supports index" },
   { daap_mslr, "login required (mslr)" },
   { daap_mspi, "supports persistent ids (mspi)" },
   { daap_msqy, "supports query" },
   { daap_msrs, "supports resolve" },
   { daap_msrv, "server info response (msrv)" },
   { daap_mstm, "timeout interval" },
   { daap_msts, "status string (msts)" },
   { daap_mstt, "status (mstt)" },
   { daap_msup, "supports update (msup)" },
   { daap_msur, "server revision" },
   { daap_mtco, "specified total count (mtco)" },
   { daap_mudl, "deleted id listing" },
   { daap_mupd, "update response" },
   { daap_musr, "server revision" },
   { daap_muty, "update type" },
   { daap_prsv, "resolve" },
   { 0,         NULL}
};
static value_string_ext vals_tag_code_ext = VALUE_STRING_EXT_INIT(vals_tag_code);

/* Initialize the protocol and registered fields */
static int proto_daap = -1;
static int hf_daap_name = -1;
static int hf_daap_size = -1;

/* Initialize the subtree pointers */
static gint ett_daap = -1;
static gint ett_daap_sub = -1;

/* Forward declarations */
static void dissect_daap_one_tag(proto_tree *tree, tvbuff_t *tvb);

static void
dissect_daap(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
   proto_item *ti;
   proto_tree *daap_tree;
   guint first_tag = 0;

   first_tag = tvb_get_ntohl(tvb, 0);
   col_set_str(pinfo->cinfo, COL_PROTOCOL, "DAAP");

   /*
    * This catches album art coming back from iTunes.
    * XXX - will those have a media type of image/png
    * rather than application/x-dmap-tagged?  If so,
    * this is no longer necessary.
    */
   if (first_tag == daap_png) {
      call_dissector(png_handle, tvb, pinfo, tree);
      return;
   }

   /* This is done in two functions on purpose. If the tvb_get_xxx()
    * functions fail, at least something will be in the info column
    */
   col_set_str(pinfo->cinfo, COL_INFO, "DAAP Response");
   col_append_fstr(pinfo->cinfo, COL_INFO, " [first tag: %s, size: %d]",
                   tvb_format_text(tvb, 0, 4),
                   tvb_get_ntohl(tvb, 4));

   if (tree) {
      ti = proto_tree_add_item(tree, proto_daap, tvb, 0, -1, ENC_NA);
      daap_tree = proto_item_add_subtree(ti, ett_daap);
      dissect_daap_one_tag(daap_tree, tvb);
   }
}

static void
dissect_daap_one_tag(proto_tree *tree, tvbuff_t *tvb)
{
   gint        offset = 0;
   gint        reported_length;
   guint32     tagname;
   guint32     tagsize;
   gint        len;
   proto_item *ti;
   proto_item *ti2;
   proto_tree *new_tree;
   tvbuff_t   *new_tvb;

   reported_length = tvb_reported_length(tvb);

   while ((offset >= 0) &&  (offset < reported_length)) {
      tagname = tvb_get_ntohl(tvb, offset);
      tagsize = tvb_get_ntohl(tvb, offset+4);
      ti = proto_tree_add_text(tree, tvb, offset, 8,
                               "Tag: %-40s %3u byte%c",
                               val_to_str_ext(tagname, &vals_tag_code_ext, "Unknown tag (0x%0x)"),
                               tagsize,
                               plurality(tagsize, ' ', 's'));

      ti2 = proto_tree_add_item(tree, hf_daap_name, tvb, offset, 4, ENC_ASCII|ENC_NA);
      PROTO_ITEM_SET_HIDDEN(ti2);
      ti2 = proto_tree_add_item(tree, hf_daap_size, tvb, offset+4, 4, ENC_BIG_ENDIAN);
      PROTO_ITEM_SET_HIDDEN(ti2);

      offset += 8;

      len = reported_length - offset; /* should be >= 0 since no exception above */
      DISSECTOR_ASSERT(len >= 0);
      if (tagsize <= (unsigned)len) {
         len = tagsize;
      }
      proto_item_set_len(ti, 8+len);              /* *Now* it's Ok to set the length.              */
                                                  /*  (Done here so that the proto_tree_add_text   */
                                                  /*   above will show tag and tagsize even if     */
                                                  /*   tagsize is very large).                     */
      switch (tagname) {
      case daap_mcon:
      case daap_msrv:
      case daap_mccr:
      case daap_mdcl:
      case daap_mlog:
      case daap_mupd:
      case daap_avdb:
      case daap_mlcl:
      case daap_mlit:
      case daap_mbcl:
      case daap_adbs:
      case daap_aply:
      case daap_apso:
      case daap_mudl:
      case daap_abro:
      case daap_abar:
      case daap_arsv:
      case daap_abal:
      case daap_abcp:
      case daap_abgn:
      case daap_prsv:
      case daap_arif:
      case dacp_casp:
      case dacp_cmgt:
      case dacp_cmst:
         /* Container tags */
         new_tree = proto_item_add_subtree(ti, ett_daap_sub);
         new_tvb  = tvb_new_subset(tvb, offset, len, len);    /* Use a new tvb so bounds checking        */
                                                              /*  works Ok when dissecting container.    */
                                                              /* Note: len is within tvb; checked above. */
                                                              /* len (see above) is used so that we'll   */
                                                              /* at least try to dissect what we have    */
                                                              /* before throwing an exception.           */
         dissect_daap_one_tag(new_tree, new_tvb);
         break;
      case daap_minm:
      case daap_msts:
      case daap_mcnm:
      case daap_mcna:
      case daap_asal:
      case daap_asar:
      case daap_ascm:
      case daap_asfm:
      case daap_aseq:
      case daap_asgn:
      case daap_asdt:
      case daap_asul:
      case daap_ascp:
      case daap_asct:
      case daap_ascn:
      case daap_aslc:
      case daap_asky:
      case daap_aeSN:
      case daap_aeNN:
      case daap_aeEN:
      case daap_assn:
      case daap_assa:
      case daap_assl:
      case daap_assc:
      case daap_asss:
      case daap_asaa:
      case daap_aspu:
      case daap_aeCR:
      case dacp_cana:
      case dacp_cang:
      case dacp_canl:
      case dacp_cann:
         /* Tags contain strings */
         proto_item_append_text(ti, "; Data: %s",
                                tvb_format_text(tvb, offset, tagsize));
         break;
      case daap_mper:
      case daap_aeGR:
      case daap_aeGU:
      case daap_asai:
      case daap_asls:
         /* Tags conain uint64 */
         proto_item_append_text(ti, "; Persistent Id: %" G_GINT64_MODIFIER "u",
                                tvb_get_ntoh64(tvb, offset));
         break;
      case daap_mstt:
         proto_item_append_text(ti, "; Status: %d",
                                tvb_get_ntohl(tvb, offset));
         break;
      case daap_musr:
      case daap_msur:
         proto_item_append_text(ti, "; Revision: %d",
                                tvb_get_ntohl(tvb, offset));
         break;
      case daap_miid:
      case daap_mcti:
      case daap_mpco:
      case daap_mlid:
         proto_item_append_text(ti, "; Id: %d",
                                tvb_get_ntohl(tvb, offset));
         break;
      case daap_mrco:
      case daap_mtco:
      case daap_mimc:
      case daap_msdc:
      case daap_mctc:
         proto_item_append_text(ti, "; Count: %d",
                                tvb_get_ntohl(tvb, offset));
         break;
      case daap_mstm:
         proto_item_append_text(ti, "; Timeout: %d seconds",
                                tvb_get_ntohl(tvb, offset));
         break;
      case daap_asda:
      case daap_asdm:
      case daap_assr:
      case daap_assz:
      case daap_asst:
      case daap_assp:
      case daap_astm:
      case daap_aeNV:
      case daap_ascd:
      case daap_ascs:
      case daap_aeSV:
      case daap_aePI:
      case daap_aeCI:
      case daap_aeGI:
      case daap_aeAI:
      case daap_aeSI:
      case daap_aeES:
      case daap_asbo:
      case daap_aeGH:
      case daap_aeGD:
      case daap_aeGE:
      case dacp_cant:
      case dacp_cast:
      case dacp_cmsr:
      case dacp_cmvo:
      case daap_meds:
         /* Tags conain uint32 */
         proto_item_append_text(ti, "; Data: %d",
                                tvb_get_ntohl(tvb, offset));
         break;

      case daap_mcty:
      case daap_asbt:
      case daap_asbr:
      case daap_asdc:
      case daap_asdn:
      case daap_astc:
      case daap_astn:
      case daap_asyr:
      case daap_ased:
         /* Tags conain uint16 */
         proto_item_append_text(ti, "; Data: %d",
                                tvb_get_ntohs(tvb, offset));
         break;

      case daap_mikd:
      case daap_msau:
      case daap_msty:
      case daap_asrv:
      case daap_asur:
      case daap_asdk:
      case daap_muty:
      case daap_msas:
      case daap_aeHV:
      case daap_aeHD:
      case daap_aePC:
      case daap_aePP:
      case daap_aeMK:
      case daap_aeSG:
      case daap_apsm:
      case daap_aprm:
      case daap_asgp:
      case daap_aePS:
      case dacp_cafs:
      case dacp_caps:
      case dacp_carp:
      case dacp_cash:
      case dacp_cavs:
         /* Tags conain uint8 */
         proto_item_append_text(ti, "; Data: %d",
                                tvb_get_guint8(tvb, offset));

         break;

      case daap_mslr:
      case daap_msal:
      case daap_msup:
      case daap_mspi:
      case daap_msex:
      case daap_msbr:
      case daap_msqy:
      case daap_msix:
      case daap_msrs:
      case daap_asco:
      case daap_asdb:
      case daap_abpl:
      case daap_aeSP:
      case daap_asbk:
         /* Tags ARE boolean. Data is (uint8), but it seems
          * the value is always zero. So, if the tag is present
          * the "bool" is true.
          */
         proto_item_append_text(ti, "; Data: True");
         break;

      case daap_mpro:
      case daap_apro:
         /* Tags conain version (uint32) */
         proto_item_append_text(ti, "; Version: %d.%d.%d.%d",
                                tvb_get_guint8(tvb, offset),
                                tvb_get_guint8(tvb, offset+1),
                                tvb_get_guint8(tvb, offset+2),
                                tvb_get_guint8(tvb, offset+3));
         break;

      case dacp_canp:
         /* now playing */
         /* bytes  4-7  contain uint32 playlist id */
         /* bytes 12-15 contain uint32 track id */
         proto_item_append_text(ti,
                                "; unknown: %d, playlist id: %d, unknown: %d, track id: %d",
                                tvb_get_ntohl(tvb, offset),
                                tvb_get_ntohl(tvb, offset+4),
                                tvb_get_ntohl(tvb, offset+8),
                                tvb_get_ntohl(tvb, offset+12));

      default:
         break;
      }
      if ((signed)tagsize < 0)   /* we'll consider a tagsize >= 0x80000000 invalid */
          break;
      offset += tagsize;
   }
   if ((offset < 0) || ((reported_length - offset) != 0)) {
       THROW(ReportedBoundsError);
   }
   return;
}


/* Register the protocol with Wireshark */
void
proto_register_daap(void)
{

   static hf_register_info hf[] = {
      { &hf_daap_name,
        { "Name", "daap.name", FT_STRING, BASE_NONE, NULL, 0x0,
          "Tag Name", HFILL}
      },
      { &hf_daap_size,
        { "Size", "daap.size", FT_UINT32, BASE_DEC, NULL, 0x0,
          "Tag Size", HFILL }
      }
   };

   static gint *ett[] = {
      &ett_daap,
      &ett_daap_sub,
   };

   proto_daap = proto_register_protocol("Digital Audio Access Protocol",
                                        "DAAP", "daap");

   proto_register_field_array(proto_daap, hf, array_length(hf));
   proto_register_subtree_array(ett, array_length(ett));
}

void
proto_reg_handoff_daap(void)
{
   dissector_handle_t daap_handle;

   daap_handle = create_dissector_handle(dissect_daap, proto_daap);
   http_port_add(TCP_PORT_DAAP);
   dissector_add_string("media_type", "application/x-dmap-tagged", daap_handle);

   png_handle = find_dissector("png");
}