epan/dissectors/packet-image-png.c

   1 /* packet-image-png.c
   2  *
   3  * Routines for PNG (Portable Network Graphics) image file dissection
   4  *
   5  * $Id$
   6  *
   7  * Copyright 2006 Ronnie Sahlberg
   8  *
   9  * Wireshark - Network traffic analyzer
  10  * By Gerald Combs <gerald@wireshark.org>
  11  * Copyright 1998 Gerald Combs
  12  *
  13  * This program is free software; you can redistribute it and/or
  14  * modify it under the terms of the GNU General Public License
  15  * as published by the Free Software Foundation; either version 2
  16  * of the License, or (at your option) any later version.
  17  *
  18  * This program is distributed in the hope that it will be useful,
  19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  * GNU General Public License for more details.
  22  *
  23  * You should have received a copy of the GNU General Public License
  24  * along with this program; if not, write to the Free Software
  25  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  26  */
  27 /* See http://www.w3.org/TR/PNG for specification
  28  */
  29
  30 #ifdef HAVE_CONFIG_H
  31 # include "config.h"
  32 #endif
  33
  34 #include <glib.h>
  35 #include <epan/packet.h>
  36
  37
  38 static int proto_png = -1;
  39 static int hf_png_signature = -1;
  40 static int hf_png_chunk_data = -1;
  41 static int hf_png_chunk_type = -1;
  42 static int hf_png_chunk_len = -1;
  43 static int hf_png_chunk_crc = -1;
  44 static int hf_png_chunk_flag_anc = -1;
  45 static int hf_png_chunk_flag_priv = -1;
  46 static int hf_png_chunk_flag_stc = -1;
  47 static int hf_png_ihdr_width = -1;
  48 static int hf_png_ihdr_height = -1;
  49 static int hf_png_ihdr_bitdepth = -1;
  50 static int hf_png_ihdr_colour_type = -1;
  51 static int hf_png_ihdr_compression_method = -1;
  52 static int hf_png_ihdr_filter_method = -1;
  53 static int hf_png_ihdr_interlace_method = -1;
  54 static int hf_png_text_keyword = -1;
  55 static int hf_png_text_string = -1;
  56 static int hf_png_time_year = -1;
  57 static int hf_png_time_month = -1;
  58 static int hf_png_time_day = -1;
  59 static int hf_png_time_hour = -1;
  60 static int hf_png_time_minute = -1;
  61 static int hf_png_time_second = -1;
  62 static int hf_png_phys_horiz = -1;
  63 static int hf_png_phys_vert = -1;
  64 static int hf_png_phys_unit = -1;
  65 static int hf_png_bkgd_palette_index = -1;
  66 static int hf_png_bkgd_greyscale = -1;
  67 static int hf_png_bkgd_red = -1;
  68 static int hf_png_bkgd_green = -1;
  69 static int hf_png_bkgd_blue = -1;
  70
  71 static gint ett_png = -1;
  72 static gint ett_png_chunk = -1;
  73 static gint ett_png_chunk_item = -1;
  74
  75
  76 static const value_string colour_type_vals[] = {
  77         { 0,    "Greyscale"},
  78         { 2,    "Truecolour"},
  79         { 3,    "Indexed-colour"},
  80         { 4,    "Greyscale with alpha"},
  81         { 6,    "Truecolour with alpha"},
  82         { 0, NULL }
  83 };
  84 static const value_string compression_method_vals[] = {
  85         { 0,    "Deflate"},
  86         { 0, NULL }
  87 };
  88 static const value_string filter_method_vals[] = {
  89         { 0,    "Adaptive"},
  90         { 0, NULL }
  91 };
  92 static const value_string interlace_method_vals[] = {
  93         { 0,    "No interlace"},
  94         { 1,    "Adam7"},
  95         { 0, NULL }
  96 };
  97
  98 static void
  99 dissect_png_ihdr(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree)
 100 {
 101         int offset=0;
 102
 103         proto_tree_add_item(tree, hf_png_ihdr_width, tvb, offset, 4, FALSE);
 104         offset+=4;
 105
 106         proto_tree_add_item(tree, hf_png_ihdr_height, tvb, offset, 4, FALSE);
 107         offset+=4;
 108
 109         proto_tree_add_item(tree, hf_png_ihdr_bitdepth, tvb, offset, 1, FALSE);
 110         offset+=1;
 111
 112         proto_tree_add_item(tree, hf_png_ihdr_colour_type, tvb, offset, 1, FALSE);
 113         offset+=1;
 114
 115         proto_tree_add_item(tree, hf_png_ihdr_compression_method, tvb, offset, 1, FALSE);
 116         offset+=1;
 117
 118         proto_tree_add_item(tree, hf_png_ihdr_filter_method, tvb, offset, 1, FALSE);
 119         offset+=1;
 120
 121         proto_tree_add_item(tree, hf_png_ihdr_interlace_method, tvb, offset, 1, FALSE);
 122         offset+=1;
 123
 124         return;
 125 }
 126
 127 static void
 128 dissect_png_text(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree)
 129 {
 130         int offset=1;
 131
 132         /* find the null that separates keyword and text string */
 133         while(1){
 134                 if(!tvb_get_guint8(tvb, offset)){
 135                         break;
 136                 }
 137                 offset++;
 138         }
 139
 140         proto_tree_add_item(tree, hf_png_text_keyword, tvb, 0, offset, FALSE);
 141         offset++;
 142
 143         proto_tree_add_item(tree, hf_png_text_string, tvb, offset, tvb_length_remaining(tvb, offset), FALSE);
 144
 145 }
 146
 147 static void
 148 dissect_png_time(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree)
 149 {
 150         proto_tree_add_item(tree, hf_png_time_year, tvb, 0, 2, FALSE);
 151         proto_tree_add_item(tree, hf_png_time_month, tvb, 2, 1, FALSE);
 152         proto_tree_add_item(tree, hf_png_time_day, tvb, 3, 1, FALSE);
 153         proto_tree_add_item(tree, hf_png_time_hour, tvb, 4, 1, FALSE);
 154         proto_tree_add_item(tree, hf_png_time_minute, tvb, 5, 1, FALSE);
 155         proto_tree_add_item(tree, hf_png_time_second, tvb, 6, 1, FALSE);
 156 }
 157
 158 static const value_string phys_unit_vals[] = {
 159         { 0,    "Unit is unknown"},
 160         { 1,    "Unit is METRE"},
 161         { 0, NULL }
 162 };
 163 static void
 164 dissect_png_phys(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree)
 165 {
 166         proto_tree_add_item(tree, hf_png_phys_horiz, tvb, 0, 4, FALSE);
 167         proto_tree_add_item(tree, hf_png_phys_vert, tvb, 4, 4, FALSE);
 168         proto_tree_add_item(tree, hf_png_phys_unit, tvb, 8, 1, FALSE);
 169 }
 170
 171 static void
 172 dissect_png_bkgd(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree)
 173 {
 174         switch(tvb_reported_length(tvb)){
 175         case 1: /* colour type 3 */
 176                 proto_tree_add_item(tree, hf_png_bkgd_palette_index, tvb, 0, 1, FALSE);
 177                 break;
 178         case 2: /* colour type 0, 4 */
 179                 proto_tree_add_item(tree, hf_png_bkgd_greyscale, tvb, 0, 2, FALSE);
 180                 break;
 181         case 6: /* colour type 2, 6 */
 182                 proto_tree_add_item(tree, hf_png_bkgd_red, tvb, 0, 2, FALSE);
 183                 proto_tree_add_item(tree, hf_png_bkgd_green, tvb, 2, 2, FALSE);
 184                 proto_tree_add_item(tree, hf_png_bkgd_blue, tvb, 4, 2, FALSE);
 185                 break;
 186         }
 187 }
 188
 189 typedef struct _chunk_dissector_t {
 190         guint32 type;
 191         const char *name;
 192         void (*dissector)(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree);
 193 } chunk_dissector_t;
 194
 195 static chunk_dissector_t chunk_table[] = {
 196         { 0x49484452, "Image Header", dissect_png_ihdr },       /* IHDR */
 197         { 0x624b4744, "Background colour", dissect_png_bkgd },  /* bKGD */
 198         { 0x70485973, "Physical pixel dimensions",
 199                                         dissect_png_phys },     /* pHYs */
 200         { 0x74455874, "Textual data", dissect_png_text },       /* tEXt */
 201         { 0x74494d45, "Image last-modification time",
 202                                         dissect_png_time },     /* tIME */
 203         { 0x49454e44, "Image Trailer", NULL },                  /* IEND */
 204         { 0, NULL, NULL }
 205 };
 206
 207 static const true_false_string png_chunk_anc = {
 208         "This is an ANCILLARY chunk",
 209         "This is a CRITICAL chunk"
 210 };
 211 static const true_false_string png_chunk_priv = {
 212         "This is a PRIVATE chunk",
 213         "This is a PUBLIC chunk"
 214 };
 215 static const true_false_string png_chunk_stc = {
 216         "This chunk is SAFE TO COPY",
 217         "This chunk is NOT safe to copy"
 218 };
 219
 220
 221 static void
 222 dissect_png(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree)
 223 {
 224         proto_tree *tree = NULL;
 225         proto_item *ti;
 226         int offset=0;
 227
 228         col_append_str(pinfo->cinfo, COL_INFO, " (PNG)");
 229
 230         if(parent_tree){
 231                 ti=proto_tree_add_item(parent_tree, proto_png, tvb, offset, -1, FALSE);
 232                 tree=proto_item_add_subtree(ti, ett_png);
 233         }
 234
 235         proto_tree_add_item(tree, hf_png_signature, tvb, offset, 8, FALSE);
 236         offset+=8;
 237
 238         while(tvb_reported_length_remaining(tvb, offset)){
 239                 proto_tree *chunk_tree=NULL;
 240                 proto_item *it=NULL;
 241                 guint32 len, type;
 242                 chunk_dissector_t *cd;
 243                 char str[5];
 244
 245                 len=tvb_get_ntohl(tvb, offset);
 246                 type=tvb_get_ntohl(tvb, offset+4);
 247                 str[0]=tvb_get_guint8(tvb, offset+4);
 248                 str[1]=tvb_get_guint8(tvb, offset+5);
 249                 str[2]=tvb_get_guint8(tvb, offset+6);
 250                 str[3]=tvb_get_guint8(tvb, offset+7);
 251                 str[4]=0;
 252
 253                 if(tree){
 254                         it=proto_tree_add_text(tree, tvb, offset, offset+8+len+4, "%s", str);
 255                         chunk_tree=proto_item_add_subtree(it, ett_png_chunk);
 256                 }
 257
 258                 proto_tree_add_item(chunk_tree, hf_png_chunk_len, tvb, offset, 4, FALSE);
 259                 offset+=4;
 260
 261
 262                 it=proto_tree_add_item(chunk_tree, hf_png_chunk_type, tvb, offset, 4, FALSE);
 263                 proto_tree_add_item(chunk_tree, hf_png_chunk_flag_anc, tvb, offset, 4, FALSE);
 264                 proto_tree_add_item(chunk_tree, hf_png_chunk_flag_priv, tvb, offset, 4, FALSE);
 265                 proto_tree_add_item(chunk_tree, hf_png_chunk_flag_stc, tvb, offset, 4, FALSE);
 266                 offset+=4;
 267
 268                 if (len >= 1000000000)
 269                         THROW(ReportedBoundsError);
 270                 cd=&chunk_table[0];
 271                 while(1){
 272                         if(cd->type==0){
 273                                 cd=NULL;
 274                                 break;
 275                         }
 276                         if(cd->type==type){
 277                                 break;
 278                         }
 279                         cd++;
 280                 }
 281                 if(chunk_tree){
 282                         proto_item_append_text(chunk_tree, " %s", cd?cd->name:"(don't know how to dissect this)");
 283                 }
 284
 285                 if(!cd){
 286                         proto_tree_add_item(chunk_tree, hf_png_chunk_data, tvb, offset, len, FALSE);
 287                 } else {
 288                         if(cd->dissector){
 289                                 tvbuff_t *next_tvb;
 290                                 proto_tree *cti=NULL;
 291
 292                                 next_tvb=tvb_new_subset(tvb, offset, MIN(tvb_length_remaining(tvb, offset), (int)len), len);
 293                                 if(it){
 294                                         cti=proto_item_add_subtree(it, ett_png_chunk_item);
 295                                 }
 296                                 cd->dissector(next_tvb, pinfo, cti);
 297                         }
 298                 }
 299                 offset+=len;
 300
 301                 proto_tree_add_item(chunk_tree, hf_png_chunk_crc, tvb, offset, 4, FALSE);
 302                 offset+=4;
 303         }
 304 }
 305
 306 void
 307 proto_register_png(void)
 308 {
 309         static hf_register_info hf[] =
 310         {
 311         { &hf_png_signature, {
 312           "PNG Signature", "png.signature", FT_BYTES, BASE_NONE,
 313           NULL, 0, NULL, HFILL }},
 314         { &hf_png_chunk_type, {
 315           "Chunk", "png.chunk.type", FT_STRING, BASE_NONE,
 316           NULL, 0, NULL, HFILL }},
 317         { &hf_png_chunk_data, {
 318           "Data", "png.chunk.data", FT_NONE, BASE_NONE,
 319           NULL, 0, NULL, HFILL }},
 320         { &hf_png_chunk_len, {
 321           "Len", "png.chunk.len", FT_UINT32, BASE_DEC,
 322           NULL, 0, NULL, HFILL }},
 323         { &hf_png_chunk_crc, {
 324           "CRC", "png.chunk.crc", FT_UINT32, BASE_HEX,
 325           NULL, 0, NULL, HFILL }},
 326         { &hf_png_chunk_flag_anc, {
 327           "Ancillary", "png.chunk.flag.ancillary", FT_BOOLEAN, 32,
 328           TFS(&png_chunk_anc), 0x20000000, NULL, HFILL }},
 329         { &hf_png_chunk_flag_priv, {
 330           "Private", "png.chunk.flag.private", FT_BOOLEAN, 32,
 331           TFS(&png_chunk_priv), 0x00200000, NULL, HFILL }},
 332         { &hf_png_chunk_flag_stc, {
 333           "Safe To Copy", "png.chunk.flag.stc", FT_BOOLEAN, 32,
 334           TFS(&png_chunk_stc), 0x00000020, NULL, HFILL }},
 335         { &hf_png_ihdr_width, {
 336           "Width", "png.ihdr.width", FT_UINT32, BASE_DEC,
 337           NULL, 0, NULL, HFILL }},
 338         { &hf_png_ihdr_height, {
 339           "Height", "png.ihdr.height", FT_UINT32, BASE_DEC,
 340           NULL, 0, NULL, HFILL }},
 341         { &hf_png_ihdr_bitdepth, {
 342           "Bit Depth", "png.ihdr.bitdepth", FT_UINT8, BASE_DEC,
 343           NULL, 0, NULL, HFILL }},
 344         { &hf_png_ihdr_colour_type, {
 345           "Colour Type", "png.ihdr.colour_type", FT_UINT8, BASE_DEC,
 346           VALS(colour_type_vals), 0, NULL, HFILL }},
 347         { &hf_png_ihdr_compression_method, {
 348           "Compression Method", "png.ihdr.compression_method", FT_UINT8, BASE_DEC,
 349           VALS(compression_method_vals), 0, NULL, HFILL }},
 350         { &hf_png_ihdr_filter_method, {
 351           "Filter Method", "png.ihdr.filter_method", FT_UINT8, BASE_DEC,
 352           VALS(filter_method_vals), 0, NULL, HFILL }},
 353         { &hf_png_ihdr_interlace_method, {
 354           "Interlace Method", "png.ihdr.interlace_method", FT_UINT8, BASE_DEC,
 355           VALS(interlace_method_vals), 0, NULL, HFILL }},
 356         { &hf_png_text_keyword, {
 357           "Keyword", "png.text.keyword", FT_STRING, BASE_NONE,
 358           NULL, 0, NULL, HFILL }},
 359         { &hf_png_text_string, {
 360           "String", "png.text.string", FT_STRING, BASE_NONE,
 361           NULL, 0, NULL, HFILL }},
 362         { &hf_png_time_year, {
 363           "Year", "png.time.year", FT_UINT16, BASE_DEC,
 364           NULL, 0, NULL, HFILL }},
 365         { &hf_png_time_month, {
 366           "Month", "png.time.month", FT_UINT8, BASE_DEC,
 367           NULL, 0, NULL, HFILL }},
 368         { &hf_png_time_day, {
 369           "Day", "png.time.day", FT_UINT8, BASE_DEC,
 370           NULL, 0, NULL, HFILL }},
 371         { &hf_png_time_hour, {
 372           "Hour", "png.time.hour", FT_UINT8, BASE_DEC,
 373           NULL, 0, NULL, HFILL }},
 374         { &hf_png_time_minute, {
 375           "Minute", "png.time.minute", FT_UINT8, BASE_DEC,
 376           NULL, 0, NULL, HFILL }},
 377         { &hf_png_time_second, {
 378           "Second", "png.time.second", FT_UINT8, BASE_DEC,
 379           NULL, 0, NULL, HFILL }},
 380         { &hf_png_phys_horiz, {
 381           "Horizontal pixels per unit", "png.phys.horiz", FT_UINT32, BASE_DEC,
 382           NULL, 0, NULL, HFILL }},
 383         { &hf_png_phys_vert, {
 384           "Vertical pixels per unit", "png.phys.vert", FT_UINT32, BASE_DEC,
 385           NULL, 0, NULL, HFILL }},
 386         { &hf_png_phys_unit, {
 387           "Unit", "png.phys.unit", FT_UINT8, BASE_DEC,
 388           VALS(phys_unit_vals), 0, NULL, HFILL }},
 389         { &hf_png_bkgd_palette_index, {
 390           "Palette Index", "png.bkgd.palette_index", FT_UINT8, BASE_DEC,
 391           NULL, 0, NULL, HFILL }},
 392         { &hf_png_bkgd_greyscale, {
 393           "Greyscale", "png.bkgd.greyscale", FT_UINT16, BASE_HEX,
 394           NULL, 0, NULL, HFILL }},
 395         { &hf_png_bkgd_red, {
 396           "Red", "png.bkgd.red", FT_UINT16, BASE_HEX,
 397           NULL, 0, NULL, HFILL }},
 398         { &hf_png_bkgd_green, {
 399           "Green", "png.bkgd.green", FT_UINT16, BASE_HEX,
 400           NULL, 0, NULL, HFILL }},
 401         { &hf_png_bkgd_blue, {
 402           "Blue", "png.bkgd.blue", FT_UINT16, BASE_HEX,
 403           NULL, 0, NULL, HFILL }},
 404         };
 405
 406         static gint *ett[] =
 407         {
 408                 &ett_png,
 409                 &ett_png_chunk,
 410                 &ett_png_chunk_item,
 411         };
 412
 413
 414         proto_png = proto_register_protocol("Portable Network Graphics","PNG","png");
 415         proto_register_field_array(proto_png, hf, array_length(hf));
 416         proto_register_subtree_array(ett, array_length(ett));
 417 }
 418
 419 void
 420 proto_reg_handoff_png(void)
 421 {
 422         dissector_handle_t png_handle;
 423
 424         png_handle = create_dissector_handle(dissect_png, proto_png);
 425         dissector_add_string("media_type", "image/png", png_handle);
 426 }