initial PNG dissector (Portable Network Graphics)

svn path=/trunk/; revision=19042

2 files changed, 301 insertions, 0 deletions

diff --git a/epan/dissectors/Makefile.common b/epan/dissectors/Makefile.common
index de1a0f4a5e..3525019c2b 100644
--- a/epan/dissectors/Makefile.common
+++ b/epan/dissectors/Makefile.common
@@ -368,6 +368,7 @@ DISSECTOR_SRC =	\
 	packet-igrp.c	\
 	packet-image-gif.c	\
 	packet-image-jfif.c	\
+	packet-image-png.c	\
 	packet-imap.c	\
 	packet-inap.c	\
 	packet-ip.c	\
diff --git a/epan/dissectors/packet-image-png.c b/epan/dissectors/packet-image-png.c
new file mode 100644
index 0000000000..ec26c582ce
--- /dev/null
+++ b/epan/dissectors/packet-image-png.c
@@ -0,0 +1,300 @@
+/* packet-image-png.c
+ *
+ * Routines for PNG (Portable Network Graphics) image file dissection
+ *
+ * $Id$
+ *
+ * Copyright 2006 Ronnie Sahlberg
+ *
+ * Ethereal - Network traffic analyzer
+ * By Gerald Combs <gerald@ethereal.com>
+ * 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ */
+/* See http://www.w3.org/TR/PNG for specification
+ */
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <glib.h>
+#include <epan/packet.h>
+
+
+static int proto_png = -1;
+static int hf_png_signature = -1;
+static int hf_png_chunk_data = -1;
+static int hf_png_chunk_type = -1;
+static int hf_png_chunk_len = -1;
+static int hf_png_chunk_crc = -1;
+static int hf_png_chunk_flag_anc = -1;
+static int hf_png_chunk_flag_priv = -1;
+static int hf_png_chunk_flag_stc = -1;
+static int hf_png_ihdr_width = -1;
+static int hf_png_ihdr_height = -1;
+static int hf_png_ihdr_bitdepth = -1;
+static int hf_png_ihdr_colour_type = -1;
+static int hf_png_ihdr_compression_method = -1;
+static int hf_png_ihdr_filter_method = -1;
+static int hf_png_ihdr_interlace_method = -1;
+
+static gint ett_png = -1;
+static gint ett_png_chunk = -1;
+static gint ett_png_chunk_item = -1;
+
+
+static const value_string colour_type_vals[] = {
+	{ 0,	"Greyscale"},
+	{ 2,	"Truecolour"},
+	{ 3,	"Indexed-colour"},
+	{ 4,	"Greyscale with alpha"},
+	{ 5,	"Truecolour with alpha"},
+	{ 0, NULL }
+};
+static const value_string compression_method_vals[] = {
+	{ 0,	"Deflate"},
+	{ 0, NULL }
+};
+static const value_string filter_method_vals[] = {
+	{ 0,	"Adaptive"},
+	{ 0, NULL }
+};
+static const value_string interlace_method_vals[] = {
+	{ 0,	"No interlace"},
+	{ 1,	"Adam7"},
+	{ 0, NULL }
+};
+
+static void
+dissect_png_ihdr(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree)
+{
+	int offset=0;
+
+	proto_tree_add_item(tree, hf_png_ihdr_width, tvb, offset, 4, FALSE);
+	offset+=4;
+
+	proto_tree_add_item(tree, hf_png_ihdr_height, tvb, offset, 4, FALSE);
+	offset+=4;
+
+	proto_tree_add_item(tree, hf_png_ihdr_bitdepth, tvb, offset, 1, FALSE);
+	offset+=1;
+
+	proto_tree_add_item(tree, hf_png_ihdr_colour_type, tvb, offset, 1, FALSE);
+	offset+=1;
+
+	proto_tree_add_item(tree, hf_png_ihdr_compression_method, tvb, offset, 1, FALSE);
+	offset+=1;
+
+	proto_tree_add_item(tree, hf_png_ihdr_filter_method, tvb, offset, 1, FALSE);
+	offset+=1;
+
+	proto_tree_add_item(tree, hf_png_ihdr_interlace_method, tvb, offset, 1, FALSE);
+	offset+=1;
+
+	return;
+}
+
+
+typedef struct _chunk_dissector_t {
+	guint32 type;
+	char *name;
+	void (*dissector)(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree);
+} chunk_dissector_t;
+
+static chunk_dissector_t chunk_table[] = {
+	{ 0x49484452, "Image Header", dissect_png_ihdr }, 	/* IHDR */
+	{ 0x49454e44, "Image Trailer", NULL }, 			/* IEND */
+	{ 0, NULL, NULL }
+};
+
+static const true_false_string png_chunk_anc = {
+	"This is an ANCILLARY chunk",
+	"This is a CRITICAL chunk"
+};
+static const true_false_string png_chunk_priv = {
+	"This is a PRIVATE chunk",
+	"This is a PUBLIC chunk"
+};
+static const true_false_string png_chunk_stc = {
+	"This chunk is SAFE TO COPY",
+	"This chunk is NOT safe to copy"
+};
+
+
+static void
+dissect_png(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree)
+{
+	proto_tree *tree = NULL;
+	proto_item *ti;
+	int offset=0;
+
+	if ( check_col( pinfo->cinfo, COL_PROTOCOL ) ) {
+		col_set_str( pinfo->cinfo, COL_PROTOCOL, "PNG" );
+	}
+
+	if ( check_col( pinfo->cinfo, COL_INFO) ) {
+		col_set_str( pinfo->cinfo, COL_INFO, "PNG image");
+	}
+
+	if(parent_tree){
+		ti=proto_tree_add_item(parent_tree, proto_png, tvb, offset, -1, FALSE);
+		tree=proto_item_add_subtree(ti, ett_png);
+	}
+
+	proto_tree_add_item(tree, hf_png_signature, tvb, offset, 8, FALSE);
+	offset+=8;
+
+	while(tvb_reported_length_remaining(tvb, offset)){
+		proto_tree *chunk_tree=NULL;
+		proto_item *it=NULL;
+		guint32 len, type;
+		chunk_dissector_t *cd;
+		char str[5];
+
+		len=tvb_get_ntohl(tvb, offset);
+		type=tvb_get_ntohl(tvb, offset+4);
+		str[0]=tvb_get_guint8(tvb, offset+4);
+		str[1]=tvb_get_guint8(tvb, offset+5);
+		str[2]=tvb_get_guint8(tvb, offset+6);
+		str[3]=tvb_get_guint8(tvb, offset+7);
+		str[4]=0;
+
+		if(tree){		
+			it=proto_tree_add_text(tree, tvb, offset, offset+8+len+4, "%s", str);
+			chunk_tree=proto_item_add_subtree(it, ett_png_chunk);
+		}
+
+		proto_tree_add_item(chunk_tree, hf_png_chunk_len, tvb, offset, 4, FALSE);
+		offset+=4;
+
+		
+		it=proto_tree_add_item(chunk_tree, hf_png_chunk_type, tvb, offset, 4, FALSE);
+		proto_tree_add_item(chunk_tree, hf_png_chunk_flag_anc, tvb, offset, 4, FALSE);
+		proto_tree_add_item(chunk_tree, hf_png_chunk_flag_priv, tvb, offset, 4, FALSE);
+		proto_tree_add_item(chunk_tree, hf_png_chunk_flag_stc, tvb, offset, 4, FALSE);
+		offset+=4;
+
+		g_assert(len<1000000000);
+		cd=&chunk_table[0];
+		while(1){
+			if(cd->type==0){
+				cd=NULL;
+				break;
+			}
+			if(cd->type==type){
+				break;
+			}
+			cd++;
+		}
+		if(chunk_tree){
+			proto_item_append_text(chunk_tree, " %s", cd?cd->name:"(dont know how to dissect this)");
+		}
+
+		if(!cd){
+			proto_tree_add_item(chunk_tree, hf_png_chunk_data, tvb, offset, len, FALSE);
+		} else {
+			if(cd->dissector){
+				tvbuff_t *next_tvb;
+				proto_tree *cti=NULL;
+
+				next_tvb=tvb_new_subset(tvb, offset, MIN(tvb_length_remaining(tvb, offset), (int)len), len);
+				if(it){		
+					cti=proto_item_add_subtree(it, ett_png_chunk_item);
+				}
+				cd->dissector(next_tvb, pinfo, cti);
+			}
+		}
+		offset+=len;
+
+		proto_tree_add_item(chunk_tree, hf_png_chunk_crc, tvb, offset, 4, FALSE);
+		offset+=4;
+	}
+}
+
+void
+proto_register_png(void)
+{
+	static hf_register_info hf[] =
+	{
+	{ &hf_png_signature, {
+	  "PNG Signature", "png.signature", FT_BYTES, BASE_DEC, 
+	  NULL, 0, "", HFILL }},
+	{ &hf_png_chunk_type, {
+	  "Chunk", "png.chunk.type", FT_STRING, BASE_NONE, 
+	  NULL, 0, "", HFILL }},
+	{ &hf_png_chunk_data, {
+	  "Data", "png.chunk.data", FT_NONE, BASE_NONE, 
+	  NULL, 0, "", HFILL }},
+	{ &hf_png_chunk_len, {
+	  "Len", "png.chunk.len", FT_UINT32, BASE_DEC, 
+	  NULL, 0, "", HFILL }},
+	{ &hf_png_chunk_crc, {
+	  "CRC", "png.chunk.crc", FT_UINT32, BASE_HEX, 
+	  NULL, 0, "", HFILL }},
+	{ &hf_png_chunk_flag_anc, {
+	  "Ancillary", "png.chunk.flag.ancillary", FT_BOOLEAN, 32, 
+	  TFS(&png_chunk_anc), 0x20000000, "", HFILL }},
+	{ &hf_png_chunk_flag_priv, {
+	  "Private", "png.chunk.flag.private", FT_BOOLEAN, 32, 
+	  TFS(&png_chunk_priv), 0x00200000, "", HFILL }},
+	{ &hf_png_chunk_flag_stc, {
+	  "Safe To Copy", "png.chunk.flag.stc", FT_BOOLEAN, 32, 
+	  TFS(&png_chunk_stc), 0x00000020, "", HFILL }},
+	{ &hf_png_ihdr_width, {
+	  "Width", "png.ihdr.width", FT_UINT32, BASE_DEC, 
+	  NULL, 0, "", HFILL }},
+	{ &hf_png_ihdr_height, {
+	  "Height", "png.ihdr.height", FT_UINT32, BASE_DEC, 
+	  NULL, 0, "", HFILL }},
+	{ &hf_png_ihdr_bitdepth, {
+	  "Bit Depth", "png.ihdr.bitdepth", FT_UINT8, BASE_DEC, 
+	  NULL, 0, "", HFILL }},
+	{ &hf_png_ihdr_colour_type, {
+	  "Colour Type", "png.ihdr.colour_type", FT_UINT8, BASE_DEC, 
+	  VALS(colour_type_vals), 0, "", HFILL }},
+	{ &hf_png_ihdr_compression_method, {
+	  "Compression Method", "png.ihdr.compression_method", FT_UINT8, BASE_DEC, 
+	  VALS(compression_method_vals), 0, "", HFILL }},
+	{ &hf_png_ihdr_filter_method, {
+	  "Filter Method", "png.ihdr.filter_method", FT_UINT8, BASE_DEC, 
+	  VALS(filter_method_vals), 0, "", HFILL }},
+	{ &hf_png_ihdr_interlace_method, {
+	  "Interlace Method", "png.ihdr.interlace_method", FT_UINT8, BASE_DEC, 
+	  VALS(interlace_method_vals), 0, "", HFILL }},
+	};
+
+	static gint *ett[] =
+	{
+		&ett_png,
+		&ett_png_chunk,
+		&ett_png_chunk_item,
+	};
+
+
+	proto_png = proto_register_protocol("Portable Network Graphics","PNG","png");
+	proto_register_field_array(proto_png, hf, array_length(hf));
+	proto_register_subtree_array(ett, array_length(ett));
+}
+
+void
+proto_reg_handoff_png(void)
+{
+	dissector_handle_t png_handle;
+
+	png_handle = create_dissector_handle(dissect_png, proto_png);
+	dissector_add_string("media_type", "image/png", png_handle);
+}