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Wireshark-dev: Re: [Wireshark-dev] asn1: New MPEG dissector

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From: "ronnie sahlberg" <ronniesahlberg@xxxxxxxxx>
Date: Sat, 26 Aug 2006 00:49:24 +0000
Oh.


Can you change the wiretap reader file to
1, add a GPL banner

in the wiretap files
1, dont read sizeof unsigned  bytes
unsigned may differ between platforms and compilers    hardcode the
exact number of bytes to read instead

2, dont read straight into a bitfield struct.
c does not define the packing order or padding of fields in a bitfield
and this would be nonportable.
please change to read into an array of char and then add code to
manually unmarshall it into the fields of the bitfield




On 8/26/06, ronnie sahlberg <ronniesahlberg@xxxxxxxxx> wrote:

the wiretap files...

On 8/26/06, ronnie sahlberg <ronniesahlberg@xxxxxxxxx> wrote:
> can you also confirm that the wiretap fiel to read the mpeg file
> format is also GPL   if so i will check it in
>
> On 8/25/06, Shaun Jackman <sjackman@xxxxxxxxx> wrote:
> > This patch posts only the asn1 portion of the previous MPEG patch. It
> > omits the plugins/mpeg/* portion. It also adds a GPL license to the
> > two new files.
> >
> > Cheers,
> > Shaun
> >
> > Signed-off-by: Shaun Jackman <sjackman@xxxxxxxxx>
> >
> > 2006-08-25  Shaun Jackman  <sjackman@xxxxxxxxx>
> >
> >  * asn1/mpeg/Makefile: New file.
> >  * asn1/mpeg/mpeg.asn: Ditto.
> >  * asn1/mpeg/packet-mpeg-template.c: Ditto.
> >  * epan/dissectors/packet-mpeg.c: Regenerate.
> >  * epan/dissectors/Makefile.in: Regenerate.
> >
> > diff --unidirectional-new-file -urXX
> > wireshark-0.99.2.orig/asn1/mpeg/Makefile
> > wireshark-0.99.2/asn1/mpeg/Makefile
> > --- wireshark-0.99.2.orig/asn1/mpeg/Makefile 1969-12-31
17:00:00.000000000
> > -0700
> > +++ wireshark-0.99.2/asn1/mpeg/Makefile 2006-08-15 15:58:43.000000000
> -0600
> > @@ -0,0 +1,14 @@
> > +DISSECTOR_FILES=packet-mpeg.c
> > +
> > +all: generate_dissector
> > +
> > +generate_dissector: $(DISSECTOR_FILES)
> > +
> > +$(DISSECTOR_FILES): ../../tools/asn2wrs.py mpeg.asn
> packet-mpeg-template.c
> > + python ../../tools/asn2wrs.py -e -p mpeg -s packet-mpeg-template
> mpeg.asn
> > +
> > +clean:
> > + rm -f parsetab.py parsetab.pyc $(DISSECTOR_FILES)
> > +
> > +copy_files: generate_dissector
> > + cp $(DISSECTOR_FILES) ../../epan/dissectors
> > diff --unidirectional-new-file -urXX
> > wireshark-0.99.2.orig/asn1/mpeg/mpeg.asn
> > wireshark-0.99.2/asn1/mpeg/mpeg.asn
> > --- wireshark-0.99.2.orig/asn1/mpeg/mpeg.asn 1969-12-31
17:00:00.000000000
> > -0700
> > +++ wireshark-0.99.2/asn1/mpeg/mpeg.asn 2006-08-25 16:53:17.000000000
> -0600
> > @@ -0,0 +1,42 @@
> > +-- ASN description of MPEG
> > +-- Written by Shaun Jackman <sjackman@xxxxxxxxx>
> > +-- Copyright 2006 Shaun Jackman
> > +--
> > +-- This program is free software; you can redistribute it and/or
> > +-- modify it under the terms of the GNU General Public License.
> > +
> > +MPEG DEFINITIONS ::= BEGIN
> > +
> > +Audio ::= SEQUENCE {
> > + sync           BIT STRING (SIZE (11)),
> > + version        ENUMERATED
> > +  { mpeg-2-5(0), reserved(1), mpeg-2(2), mpeg-1(3) },
> > + layer          ENUMERATED
> > +  { reserved(0), layer-3(1), layer-2(2), layer-1(3) },
> > + protection     ENUMERATED { crc(0), none(1) },
> > + bitrate        INTEGER (0..15),
> > + frequency      INTEGER (0..3),
> > + padding        BOOLEAN,
> > + private        BOOLEAN,
> > + channel-mode   ENUMERATED
> > +  { stereo(0), joint-stereo(1), dual-channel(2), single-channel(3) },
> > + mode-extension INTEGER (0..3),
> > + copyright      BOOLEAN,
> > + original       BOOLEAN,
> > + emphasis       ENUMERATED
> > +  { none(0), em-50-15-ms(1), reserved(2), ccit-j-17(3) }
> > +}
> > +
> > +ID3v1 ::= SEQUENCE {
> > + tag     OCTET STRING (SIZE (3)),
> > + title   OCTET STRING (SIZE (30)),
> > + artist  OCTET STRING (SIZE (30)),
> > + album   OCTET STRING (SIZE (30)),
> > + year    OCTET STRING (SIZE (4)),
> > + comment OCTET STRING (SIZE (28)),
> > + zero    INTEGER (0..255),
> > + track   INTEGER (0..255),
> > + genre   INTEGER (0..255)
> > +}
> > +
> > +END
> > diff --unidirectional-new-file -urXX
> > wireshark-0.99.2.orig/asn1/mpeg/packet-mpeg-template.c
> > wireshark-0.99.2/asn1/mpeg/packet-mpeg-template.c
> > --- wireshark-0.99.2.orig/asn1/mpeg/packet-mpeg-template.c 1969-12-31
> > 17:00:00.000000000 -0700
> > +++ wireshark-0.99.2/asn1/mpeg/packet-mpeg-template.c 2006-08-25
> > 16:51:34.000000000 -0600
> > @@ -0,0 +1,238 @@
> > +/* MPEG packet decoder.
> > + * Written by Shaun Jackman <sjackman@xxxxxxxxx>.
> > + * Copyright 2006 Shaun Jackman
> > + *
> > + * This program is free software; you can redistribute it and/or
> > + * modify it under the terms of the GNU General Public License.
> > + */
> > +
> > +#ifdef HAVE_CONFIG_H
> > +# include "config.h"
> > +#endif
> > +
> > +#include <stdio.h>
> > +#include <string.h>
> > +
> > +#include <glib.h>
> > +
> > +#include <epan/packet.h>
> > +#include <epan/prefs.h>
> > +
> > +#include "packet-per.h"
> > +
> > +#include "packet-mpeg-hf.c"
> > +#include "packet-mpeg-ett.c"
> > +#include "packet-mpeg-fn.c"
> > +
> > +static int hf_mpeg_audio = -1;
> > +static int hf_mpeg_data = -1;
> > +static int hf_mpeg_padbytes = -1;
> > +static int hf_id3v1 = -1;
> > +static int hf_id3v2 = -1;
> > +
> > +struct header {
> > + unsigned emphasis   :2;
> > + unsigned original   :1;
> > + unsigned copyright  :1;
> > + unsigned mode_ext   :2;
> > + unsigned mode       :2;
> > + unsigned private    :1;
> > + unsigned padding    :1;
> > + unsigned frequency  :2;
> > + unsigned bitrate    :4;
> > + unsigned protection :1;
> > + unsigned layer      :2;
> > + unsigned version    :2;
> > + unsigned sync       :11;
> > +};
> > +
> > +enum { SYNC = 0x7ff };
> > +static const int versions[4] = { 2, -1, 1, 0 };
> > +static const int layers[4] = { -1, 2, 1, 0 };
> > +
> > +static const unsigned samples_per_frame[3][3] = {
> > + { 384, 1152, 1152 },
> > + { 384, 1152, 576 },
> > + { 384, 1152, 576 },
> > +};
> > +
> > +static const unsigned bitrates[3][3][16] = { /* kb/s */
> > +  {
> > + { 0, 32, 64, 96, 128, 160, 192, 224, 256, 288, 320, 352, 384, 416, 448
> },
> > + { 0, 32, 48, 56,  64,  80,  96, 112, 128, 160, 192, 224, 256, 320, 384
> },
> > + { 0, 32, 40, 48,  56,  64,  80,  96, 112, 128, 160, 192, 224, 256, 320
> },
> > +  },
> > +  {
> > + { 0, 32, 48, 56,  64,  80,  96, 112, 128, 144, 160, 176, 192, 224, 256
> },
> > + { 0,  8, 16, 24,  32,  40,  48,  56,  64,  80,  96, 112, 128, 144, 160
> },
> > + { 0,  8, 16, 24,  32,  40,  48,  56,  64,  80,  96, 112, 128, 144, 160
> },
> > +  },
> > +  {
> > + { 0, 32, 48, 56,  64,  80,  96, 112, 128, 144, 160, 176, 192, 224, 256
> },
> > + { 0,  8, 16, 24,  32,  40,  48,  56,  64,  80,  96, 112, 128, 144, 160
> },
> > + { 0,  8, 16, 24,  32,  40,  48,  56,  64,  80,  96, 112, 128, 144, 160
> },
> > +  },
> > +};
> > +
> > +static const unsigned frequencies[3][4] = {
> > + { 44100, 48000, 32000 },
> > + { 22050, 24000, 16000 },
> > + { 11025, 12000, 8000 },
> > +};
> > +static const unsigned padding[3] = { 4, 1, 1 };
> > +
> > +static size_t
> > +read_header(tvbuff_t *tvb, packet_info *pinfo, struct header *header)
> > +{
> > + size_t data_size = 0;
> > + uint32_t h = tvb_get_ntohl(tvb, 0);
> > + memcpy(header, &h, sizeof *header);
> > + if (header->sync == SYNC) {
> > +  int version = versions[header->version];
> > +  int layer = layers[header->layer];
> > +  if (version >= 0 && layer >= 0) {
> > +   unsigned bitrate = bitrates[version][layer][header->bitrate] * 1000;
> > +   unsigned frequency = frequencies[version][header->frequency];
> > +   if (check_col(pinfo->cinfo, COL_PROTOCOL)) {
> > +    static const char *version_names[] = { "1", "2", "2.5" };
> > +    col_add_fstr(pinfo->cinfo, COL_PROTOCOL,
> > +      "MPEG-%s", version_names[version]);
> > +   }
> > +   if (check_col(pinfo->cinfo, COL_INFO))
> > +    col_add_fstr(pinfo->cinfo, COL_INFO,
> > +      "Audio Layer %d", layer+1);
> > +   if (bitrate > 0 && frequency > 0) {
> > +    unsigned samples = samples_per_frame[version][layer];
> > +    data_size = bitrate * samples / frequency / 8 - sizeof header;
> > +    if (check_col(pinfo->cinfo, COL_DEF_SRC)) {
> > +     SET_ADDRESS(&pinfo->src, AT_NONE, 0, NULL);
> > +     col_add_fstr(pinfo->cinfo, COL_DEF_SRC,
> > +       "%d kb/s", bitrate / 1000);
> > +    }
> > +    if (check_col(pinfo->cinfo, COL_DEF_DST)) {
> > +     SET_ADDRESS(&pinfo->dst, AT_NONE, 0, NULL);
> > +     col_add_fstr(pinfo->cinfo, COL_DEF_DST,
> > +       "%g kHz", frequency / (float)1000);
> > +    }
> > +   }
> > +  } else {
> > +   if (check_col(pinfo->cinfo, COL_PROTOCOL))
> > +    col_add_str(pinfo->cinfo, COL_PROTOCOL, "MPEG");
> > +  }
> > + }
> > + return data_size;
> > +}
> > +
> > +static void
> > +dissect_mpa(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
> > +{
> > + struct header header;
> > + size_t data_size = read_header(tvb, pinfo, &header);
> > + if (tree == NULL)
> > +  return;
> > +
> > + if (header.sync != SYNC)
> > +  return;
> > + asn1_ctx_t asn1_ctx;
> > + asn1_ctx_init(&asn1_ctx, ASN1_ENC_PER, TRUE, pinfo);
> > + int offset = 0;
> > + offset = dissect_mpeg_Audio(tvb, offset, &asn1_ctx,
> > +   tree, hf_mpeg_audio);
> > + if (data_size > 0) {
> > +  proto_tree_add_item(tree, hf_mpeg_data, tvb,
> > +    offset / 8, data_size, FALSE);
> > +  offset += data_size * 8;
> > +  if (header.padding)
> > +   proto_tree_add_item(tree, hf_mpeg_padbytes, tvb,
> > +     offset / 8, 1, FALSE);
> > + }
> > +}
> > +
> > +static void
> > +dissect_id3v1(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
> > +{
> > + if (check_col(pinfo->cinfo, COL_PROTOCOL))
> > +  col_set_str(pinfo->cinfo, COL_PROTOCOL, "ID3v1");
> > + if (tree == NULL)
> > +  return;
> > + asn1_ctx_t asn1_ctx;
> > + asn1_ctx_init(&asn1_ctx, ASN1_ENC_PER, TRUE, pinfo);
> > + dissect_mpeg_ID3v1(tvb, 0, &asn1_ctx,
> > +   tree, hf_id3v1);
> > +}
> > +
> > +static void
> > +dissect_id3v2(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
> > +{
> > + if (check_col(pinfo->cinfo, COL_PROTOCOL))
> > +  col_set_str(pinfo->cinfo, COL_PROTOCOL, "ID3v2");
> > + proto_tree_add_item(tree, hf_id3v2, tvb,
> > +   0, -1, FALSE);
> > +}
> > +
> > +static void
> > +dissect_mpeg(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
> > +{
> > + if (check_col(pinfo->cinfo, COL_PROTOCOL))
> > +  col_clear(pinfo->cinfo, COL_PROTOCOL);
> > + if (check_col(pinfo->cinfo, COL_INFO))
> > +  col_clear(pinfo->cinfo, COL_INFO);
> > +
> > + int magic = tvb_get_ntoh24(tvb, 0);
> > + switch (magic) {
> > +  case 0x544147:
> > +   dissect_id3v1(tvb, pinfo, tree);
> > +   break;
> > +  case 0x494433:
> > +   dissect_id3v2(tvb, pinfo, tree);
> > +   break;
> > +  default:
> > +   dissect_mpa(tvb, pinfo, tree);
> > + }
> > +}
> > +
> > +static int proto_mpeg = -1;
> > +
> > +void
> > +proto_register_mpeg(void)
> > +{
> > + static hf_register_info hf[] = {
> > +#include "packet-mpeg-hfarr.c"
> > +  { &hf_mpeg_audio,
> > +   { "MPEG Audio", "mpeg.audio",
> > +    FT_NONE, BASE_NONE, NULL, 0, NULL, HFILL }},
> > +  { &hf_mpeg_data,
> > +   { "Data", "mpeg.data",
> > +    FT_BYTES, BASE_NONE, NULL, 0, NULL, HFILL }},
> > +  { &hf_mpeg_padbytes,
> > +   { "Padding", "mpeg.padbytes",
> > +    FT_BYTES, BASE_NONE, NULL, 0, NULL, HFILL }},
> > +
> > +  { &hf_id3v1,
> > +   { "ID3v1", "id3v1",
> > +    FT_NONE, BASE_NONE, NULL, 0, NULL, HFILL }},
> > +  { &hf_id3v2,
> > +   { "ID3v2", "id3v2",
> > +    FT_NONE, BASE_NONE, NULL, 0, NULL, HFILL }},
> > + };
> > +
> > + static gint *ett[] = {
> > +#include "packet-mpeg-ettarr.c"
> > + };
> > +
> > + if (proto_mpeg != -1)
> > +  return;
> > +
> > + proto_mpeg = proto_register_protocol(
> > +   "Moving Picture Experts Group", "MPEG", "mpeg");
> > + proto_register_field_array(proto_mpeg, hf, array_length(hf));
> > + proto_register_subtree_array(ett, array_length(ett));
> > +}
> > +
> > +void
> > +proto_reg_handoff_mpeg(void)
> > +{
> > + dissector_handle_t mpeg_handle = create_dissector_handle(
> > +   dissect_mpeg, proto_mpeg);
> > + dissector_add("wtap_encap", WTAP_ENCAP_MPEG, mpeg_handle);
> > +}
> >
> >
>
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