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I was capturing an RTP stream the other day which contained JPEG images streamed according to RFC 2435. However, Wireshark reported them as malformed. After some debugging of the Wireshark code it turned out that the decoding of JPEG images which contain a quantization table was incorrect. I have attached a patch to correct the decoding. svn path=/trunk/; revision=24246
290 lines
7.9 KiB
C
290 lines
7.9 KiB
C
/* packet-jpeg.c
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*
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* Routines for RFC 2435 JPEG dissection
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*
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* $Id$
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*
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* Copyright 2006
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* Erwin Rol <erwin@erwinrol.com>
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* Copyright 2001,
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* Francisco Javier Cabello Torres, <fjcabello@vtools.es>
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 1998 Gerald Combs
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#include <glib.h>
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#include <epan/packet.h>
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#include <stdio.h>
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#include <string.h>
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#include <epan/rtp_pt.h>
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/* JPEG header fields */
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static int hf_rtp_jpeg_main_hdr = -1;
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static int hf_rtp_jpeg_main_hdr_ts = -1;
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static int hf_rtp_jpeg_main_hdr_offs = -1;
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static int hf_rtp_jpeg_main_hdr_type = -1;
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static int hf_rtp_jpeg_main_hdr_q = -1;
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static int hf_rtp_jpeg_main_hdr_width = -1;
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static int hf_rtp_jpeg_main_hdr_height = -1;
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static int hf_rtp_jpeg_restart_hdr = -1;
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static int hf_rtp_jpeg_restart_hdr_interval = -1;
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static int hf_rtp_jpeg_restart_hdr_f = -1;
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static int hf_rtp_jpeg_restart_hdr_l = -1;
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static int hf_rtp_jpeg_restart_hdr_count = -1;
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static int hf_rtp_jpeg_qtable_hdr = -1;
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static int hf_rtp_jpeg_qtable_hdr_mbz = -1;
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static int hf_rtp_jpeg_qtable_hdr_prec = -1;
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static int hf_rtp_jpeg_qtable_hdr_length = -1;
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static int hf_rtp_jpeg_qtable_hdr_data = -1;
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static int hf_rtp_jpeg_payload = -1;
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static int proto_jpeg = -1;
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/* JPEG fields defining a sub tree */
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static gint ett_jpeg = -1;
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static void
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dissect_jpeg( tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree )
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{
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proto_item *ti = NULL;
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proto_tree *jpeg_tree = NULL;
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proto_tree *main_hdr_tree = NULL;
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proto_tree *restart_hdr_tree = NULL;
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proto_tree *qtable_hdr_tree = NULL;
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guint32 fragment_offset = 0;
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guint16 len = 0;
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guint8 type = 0;
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guint8 q = 0;
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gint h = 0;
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gint w = 0;
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unsigned int offset = 0;
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if ( check_col( pinfo->cinfo, COL_PROTOCOL ) ) {
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col_set_str( pinfo->cinfo, COL_PROTOCOL, "JPEG" );
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}
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if ( check_col( pinfo->cinfo, COL_INFO) ) {
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col_set_str( pinfo->cinfo, COL_INFO, "JPEG message");
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}
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if ( tree ) {
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ti = proto_tree_add_item( tree, proto_jpeg, tvb, offset, -1, FALSE );
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jpeg_tree = proto_item_add_subtree( ti, ett_jpeg );
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ti = proto_tree_add_item(jpeg_tree, hf_rtp_jpeg_main_hdr, tvb, offset, 8, FALSE);
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main_hdr_tree = proto_item_add_subtree(ti, ett_jpeg);
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proto_tree_add_item(main_hdr_tree, hf_rtp_jpeg_main_hdr_ts, tvb, offset, 1, FALSE);
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offset += 1;
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proto_tree_add_item(main_hdr_tree, hf_rtp_jpeg_main_hdr_offs, tvb, offset, 3, FALSE);
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fragment_offset = tvb_get_ntoh24(tvb, offset);
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offset += 3;
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proto_tree_add_item(main_hdr_tree, hf_rtp_jpeg_main_hdr_type, tvb, offset, 1, FALSE);
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type = tvb_get_guint8(tvb, offset);
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offset += 1;
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proto_tree_add_item(main_hdr_tree, hf_rtp_jpeg_main_hdr_q, tvb, offset, 1, FALSE);
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q = tvb_get_guint8(tvb, offset);
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offset += 1;
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w = tvb_get_guint8(tvb, offset) * 8;
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proto_tree_add_uint(main_hdr_tree, hf_rtp_jpeg_main_hdr_width, tvb, offset, 1, w);
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offset += 1;
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h = tvb_get_guint8(tvb, offset) * 8;
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proto_tree_add_uint(main_hdr_tree, hf_rtp_jpeg_main_hdr_height, tvb, offset, 1, h);
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offset += 1;
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if (type >= 64 && type <= 127) {
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ti = proto_tree_add_item(jpeg_tree, hf_rtp_jpeg_restart_hdr, tvb, offset, 4, FALSE);
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restart_hdr_tree = proto_item_add_subtree(ti, ett_jpeg);
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proto_tree_add_item(restart_hdr_tree, hf_rtp_jpeg_restart_hdr_interval, tvb, offset, 2, FALSE);
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offset += 2;
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proto_tree_add_item(restart_hdr_tree, hf_rtp_jpeg_restart_hdr_f, tvb, offset, 2, FALSE);
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proto_tree_add_item(restart_hdr_tree, hf_rtp_jpeg_restart_hdr_l, tvb, offset, 2, FALSE);
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proto_tree_add_item(restart_hdr_tree, hf_rtp_jpeg_restart_hdr_count, tvb, offset, 2, FALSE);
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offset += 2;
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}
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if (q >= 128 && fragment_offset == 0) {
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ti = proto_tree_add_item(jpeg_tree, hf_rtp_jpeg_qtable_hdr, tvb, offset, -1, FALSE);
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qtable_hdr_tree = proto_item_add_subtree(ti, ett_jpeg);
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proto_tree_add_item(qtable_hdr_tree, hf_rtp_jpeg_qtable_hdr_mbz, tvb, offset, 1, FALSE);
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offset += 1;
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proto_tree_add_item(qtable_hdr_tree, hf_rtp_jpeg_qtable_hdr_prec, tvb, offset, 1, FALSE);
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offset += 1;
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proto_tree_add_item(qtable_hdr_tree, hf_rtp_jpeg_qtable_hdr_length, tvb, offset, 2, FALSE);
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len = tvb_get_ntohs(tvb, offset);
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offset += 2;
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if (len > 0) {
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proto_tree_add_item(qtable_hdr_tree, hf_rtp_jpeg_qtable_hdr_data, tvb, offset, len, FALSE);
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offset += len;
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}
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proto_item_set_len(ti, len + 4);
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}
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/* The rest of the packet is the JPEG data */
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proto_tree_add_item( jpeg_tree, hf_rtp_jpeg_payload, tvb, offset, -1, FALSE );
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}
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}
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void
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proto_register_jpeg(void)
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{
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static hf_register_info hf[] =
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{
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{ &hf_rtp_jpeg_main_hdr, {
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"Main Header",
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"jpeg.main_hdr",
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FT_NONE, BASE_NONE, NULL, 0,
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"", HFILL
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}},
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{ &hf_rtp_jpeg_main_hdr_ts, {
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"Type Specific",
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"jpeg.main_hdr.ts",
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FT_UINT8, BASE_DEC, NULL, 0,
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"", HFILL
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}},
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{ &hf_rtp_jpeg_main_hdr_offs, {
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"Fragement Offset",
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"jpeg.main_hdr.offset",
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FT_UINT24, BASE_DEC, NULL, 0,
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"", HFILL
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}},
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{ &hf_rtp_jpeg_main_hdr_type, {
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"Type",
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"jpeg.main_hdr.type",
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FT_UINT8, BASE_DEC, NULL, 0,
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"", HFILL
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}},
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{ &hf_rtp_jpeg_main_hdr_q, {
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"Q",
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"jpeg.main_hdr.q",
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FT_UINT8, BASE_DEC, NULL, 0,
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"", HFILL
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}},
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{ &hf_rtp_jpeg_main_hdr_width, {
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"Width",
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"jpeg.main_hdr.width",
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FT_UINT8, BASE_DEC, NULL, 0,
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"", HFILL
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}},
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{ &hf_rtp_jpeg_main_hdr_height, {
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"Height",
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"jpeg.main_hdr.height",
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FT_UINT8, BASE_DEC, NULL, 0,
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"", HFILL
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}},
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{ &hf_rtp_jpeg_restart_hdr, {
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"Restart Marker Header",
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"jpeg.restart_hdr",
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FT_NONE, BASE_NONE, NULL, 0,
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"", HFILL
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}},
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{ &hf_rtp_jpeg_restart_hdr_interval, {
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"Restart Interval",
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"jpeg.restart_hdr.interval",
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FT_UINT16, BASE_DEC, NULL, 0,
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"", HFILL
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}},
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{ &hf_rtp_jpeg_restart_hdr_f, {
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"F",
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"jpeg.restart_hdr.f",
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FT_UINT16, BASE_DEC, NULL, 0x8000,
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"", HFILL
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}},
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{ &hf_rtp_jpeg_restart_hdr_l, {
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"L",
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"jpeg.restart_hdr.l",
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FT_UINT16, BASE_DEC, NULL, 0x4000,
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"", HFILL
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}},
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{ &hf_rtp_jpeg_restart_hdr_count, {
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"Restart Count",
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"jpeg.restart_hdr.count",
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FT_UINT16, BASE_DEC, NULL, 0x3FFF,
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"", HFILL
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}},
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{ &hf_rtp_jpeg_qtable_hdr, {
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"Quantization Table Header",
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"jpeg.qtable_hdr",
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FT_NONE, BASE_NONE, NULL, 0,
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"", HFILL
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}},
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{ &hf_rtp_jpeg_qtable_hdr_mbz, {
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"MBZ",
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"jpeg.qtable_hdr.mbz",
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FT_UINT8, BASE_DEC, NULL, 0,
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"", HFILL
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}},
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{ &hf_rtp_jpeg_qtable_hdr_prec, {
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"Precision",
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"jpeg.qtable_hdr.precision",
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FT_UINT8, BASE_DEC, NULL, 0,
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"", HFILL
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}},
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{ &hf_rtp_jpeg_qtable_hdr_length, {
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"Length",
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"jpeg.qtable_hdr.length",
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FT_UINT16, BASE_DEC, NULL, 0,
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"", HFILL
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}},
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{ &hf_rtp_jpeg_qtable_hdr_data, {
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"Quantization Table Data",
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"jpeg.qtable_hdr.data",
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FT_BYTES, BASE_DEC, NULL, 0,
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"", HFILL
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}},
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{ &hf_rtp_jpeg_payload, {
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"Payload",
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"jpeg.payload",
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FT_BYTES, BASE_DEC, NULL, 0,
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"", HFILL
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}},
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};
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static gint *ett[] =
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{
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&ett_jpeg,
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};
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proto_jpeg = proto_register_protocol("RFC 2435 JPEG","JPEG","jpeg");
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proto_register_field_array(proto_jpeg, hf, array_length(hf));
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proto_register_subtree_array(ett, array_length(ett));
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}
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void
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proto_reg_handoff_jpeg(void)
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{
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dissector_handle_t jpeg_handle;
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jpeg_handle = create_dissector_handle(dissect_jpeg, proto_jpeg);
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dissector_add("rtp.pt", PT_JPEG, jpeg_handle);
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}
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