packet-image-jfif.c

   1 /* packet-image-jfif.c
   2  *
   3  * Routines for JFIF image/jpeg media dissection
   4  * Copyright 2004, Olivier Biot <olivier.biot (ad) siemens.com>
   5  *
   6  * $Id: packet-image-jfif.c,v 1.2 2004/01/06 00:09:48 guy Exp $
   7  *
   8  * Ethereal - Network traffic analyzer
   9  * By Gerald Combs <gerald@ethereal.com>
  10  * Copyright 1998 Gerald Combs
  11  *
  12  * JFIF media decoding functionality provided by Olivier Biot.
  13  *
  14  * The JFIF specifications are found at several locations, such as:
  15  * http://www.jpeg.org/public/jfif.pdf
  16  * http://www.w3.org/Graphics/JPEG/itu-t81.pdf
  17  *
  18  * This program is free software; you can redistribute it and/or
  19  * modify it under the terms of the GNU General Public License
  20  * as published by the Free Software Foundation; either version 2
  21  * of the License, or (at your option) any later version.
  22  *
  23  * This program is distributed in the hope that it will be useful,
  24  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  25  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  26  * GNU General Public License for more details.
  27  *
  28  * You should have received a copy of the GNU General Public License
  29  * along with this program; if not, write to the Free Software
  30  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  31  */
  32
  33 /* Edit this file with 4-space tabulation */
  34
  35 #ifdef HAVE_CONFIG_H
  36 # include "config.h"
  37 #endif
  38
  39 #include <stdio.h>
  40 #include <stdlib.h>
  41 #include <string.h>
  42
  43 #include <glib.h>
  44
  45 #ifdef NEED_SNPRINTF_H
  46 # include "snprintf.h"
  47 #endif
  48
  49 #include <epan/packet.h>
  50
  51 /* General-purpose debug logger.
  52  * Requires double parentheses because of variable arguments of printf().
  53  *
  54  * Enable debug logging for JFIF by defining AM_CFLAGS
  55  * so that it contains "-DDEBUG_image_jfif" or "-DDEBUG_image"
  56  */
  57 #if (defined(DEBUG_image_jfif) || defined(DEBUG_image))
  58 #define DebugLog(x) \
  59         printf("%s:%u: ", __FILE__, __LINE__); \
  60         printf x; \
  61         fflush(stdout)
  62 #else
  63 #define DebugLog(x) ;
  64 #endif
  65
  66 #define PLURALIZE(x) ((x) == 1 ? "" : "s")
  67
  68 #define IMG_JFIF "image-jfif"
  69
  70 /************************** Variable declarations **************************/
  71
  72 #define MARKER_TEM              0xFF01
  73
  74 /* 0xFF02 -- 0xFFBF are reserved */
  75
  76 #define MARKER_SOF0             0xFFC0
  77 #define MARKER_SOF1             0xFFC1
  78 #define MARKER_SOF2             0xFFC2
  79 #define MARKER_SOF3             0xFFC3
  80
  81 #define MARKER_DHT              0xFFC4
  82
  83 #define MARKER_SOF5             0xFFC5
  84 #define MARKER_SOF6             0xFFC6
  85 #define MARKER_SOF7             0xFFC7
  86 #define MARKER_SOF8             0xFFC8
  87 #define MARKER_SOF9             0xFFC9
  88 #define MARKER_SOF10    0xFFCA
  89 #define MARKER_SOF11    0xFFCB
  90
  91 #define MARKER_DAC              0xFFCC
  92
  93 #define MARKER_SOF13    0xFFCD
  94 #define MARKER_SOF14    0xFFCE
  95 #define MARKER_SOF15    0xFFCF
  96
  97 #define MARKER_RST0             0xFFD0
  98 #define MARKER_RST1             0xFFD1
  99 #define MARKER_RST2             0xFFD2
 100 #define MARKER_RST3             0xFFD3
 101 #define MARKER_RST4             0xFFD4
 102 #define MARKER_RST5             0xFFD5
 103 #define MARKER_RST6             0xFFD6
 104 #define MARKER_RST7             0xFFD7
 105
 106 #define MARKER_FFDB             0xFFDB
 107 #define MARKER_SOI              0xFFD8
 108 #define MARKER_EOI              0xFFD9
 109 #define MARKER_SOS              0xFFDA
 110 #define MARKER_DQT              0xFFDB
 111 #define MARKER_DNL              0xFFDC
 112 #define MARKER_DRI              0xFFDD
 113 #define MARKER_DHP              0xFFDE
 114 #define MARKER_EXP              0xFFDF
 115
 116 #define MARKER_APP0             0xFFE0
 117 #define MARKER_APP1             0xFFE1
 118 #define MARKER_APP2             0xFFE2
 119 #define MARKER_APP3             0xFFE3
 120 #define MARKER_APP4             0xFFE4
 121 #define MARKER_APP5             0xFFE5
 122 #define MARKER_APP6             0xFFE6
 123 #define MARKER_APP7             0xFFE7
 124 #define MARKER_APP8             0xFFE8
 125 #define MARKER_APP9             0xFFE9
 126 #define MARKER_APP10    0xFFEA
 127 #define MARKER_APP11    0xFFEB
 128 #define MARKER_APP12    0xFFEC
 129 #define MARKER_APP13    0xFFED
 130 #define MARKER_APP14    0xFFEE
 131 #define MARKER_APP15    0xFFEF
 132
 133 #define MARKER_JPG0             0xFFF0
 134 #define MARKER_JPG1             0xFFF1
 135 #define MARKER_JPG2             0xFFF2
 136 #define MARKER_JPG3             0xFFF3
 137 #define MARKER_JPG4             0xFFF4
 138 #define MARKER_JPG5             0xFFF5
 139 #define MARKER_JPG6             0xFFF6
 140 #define MARKER_JPG7             0xFFF7
 141 #define MARKER_JPG8             0xFFF8
 142 #define MARKER_JPG9             0xFFF9
 143 #define MARKER_JPG10    0xFFFA
 144 #define MARKER_JPG11    0xFFFB
 145 #define MARKER_JPG12    0xFFFC
 146 #define MARKER_JPG13    0xFFFD
 147
 148 #define MARKER_COM              0xFFFE
 149
 150 #define marker_has_length(marker) ( ! ( \
 151            ((marker) == MARKER_TEM) \
 152         || ((marker) == MARKER_SOI) \
 153         || ((marker) == MARKER_EOI) \
 154         || ( ((marker) >= MARKER_RST0) && ((marker) <= MARKER_RST7) ) \
 155         ) )
 156
 157
 158 static const value_string vals_marker[] = {
 159         { MARKER_TEM,   "Reserved - For temporary private use in arithmetic coding" },
 160         { MARKER_SOF0,  "Start of Frame (non-differential, Huffman coding) - Baseline DCT" },
 161         { MARKER_SOF1,  "Start of Frame (non-differential, Huffman coding) - Extended sequential DCT" },
 162         { MARKER_SOF2,  "Start of Frame (non-differential, Huffman coding) - Progressive DCT" },
 163         { MARKER_SOF3,  "Start of Frame (non-differential, Huffman coding) - Lossless (sequential)" },
 164         { MARKER_DHT,   "Define Huffman table(s)" },
 165         { MARKER_SOF5,  "Start of Frame (differential, Huffman coding) - Differential sequential DCT" },
 166         { MARKER_SOF6,  "Start of Frame (differential, Huffman coding) - Differential progressive DCT" },
 167         { MARKER_SOF7,  "Start of Frame (differential, Huffman coding) - Differential lossless (sequential)" },
 168         { MARKER_SOF8,  "Start of Frame (non-differential, arithmetic coding) - Reserved for JPEG extensions" },
 169         { MARKER_SOF9,  "Start of Frame (non-differential, arithmetic coding) - Extended sequential DCT" },
 170         { MARKER_SOF10, "Start of Frame (non-differential, arithmetic coding) - Progressive DCT" },
 171         { MARKER_SOF11, "Start of Frame (non-differential, arithmetic coding) - Lossless (sequential)" },
 172         { MARKER_DAC,   "Define arithmetic coding conditioning(s)" },
 173         { MARKER_SOF13, "Start of Frame (differential, arithmetic coding) - Differential sequential DCT" },
 174         { MARKER_SOF14, "Start of Frame (differential, arithmetic coding) - Differential progressive DCT" },
 175         { MARKER_SOF15, "Start of Frame (differential, arithmetic coding) - Differential lossless (sequential)" },
 176         { MARKER_RST0,  "Restart interval termination - Restart with modulo 8 count 0" },
 177         { MARKER_RST1,  "Restart interval termination - Restart with modulo 8 count 1" },
 178         { MARKER_RST2,  "Restart interval termination - Restart with modulo 8 count 2" },
 179         { MARKER_RST3,  "Restart interval termination - Restart with modulo 8 count 3" },
 180         { MARKER_RST4,  "Restart interval termination - Restart with modulo 8 count 4" },
 181         { MARKER_RST5,  "Restart interval termination - Restart with modulo 8 count 5" },
 182         { MARKER_RST6,  "Restart interval termination - Restart with modulo 8 count 6" },
 183         { MARKER_RST7,  "Restart interval termination - Restart with modulo 8 count 7" },
 184         { MARKER_SOI,   "Start of Image" },
 185         { MARKER_EOI,   "End of Image" },
 186         { MARKER_SOS,   "Start of Scan" },
 187         { MARKER_DQT,   "Define quantization table(s)" },
 188         { MARKER_DNL,   "Define number of lines" },
 189         { MARKER_DRI,   "Define restart interval" },
 190         { MARKER_DHP,   "Define hierarchical progression" },
 191         { MARKER_EXP,   "Expand reference component(s)" },
 192         { MARKER_APP0,  "Reserved for application segments - 0" },
 193         { MARKER_APP1,  "Reserved for application segments - 1" },
 194         { MARKER_APP2,  "Reserved for application segments - 2" },
 195         { MARKER_APP3,  "Reserved for application segments - 3" },
 196         { MARKER_APP4,  "Reserved for application segments - 4" },
 197         { MARKER_APP5,  "Reserved for application segments - 5" },
 198         { MARKER_APP6,  "Reserved for application segments - 6" },
 199         { MARKER_APP7,  "Reserved for application segments - 7" },
 200         { MARKER_APP8,  "Reserved for application segments - 8" },
 201         { MARKER_APP9,  "Reserved for application segments - 9" },
 202         { MARKER_APP10, "Reserved for application segments - 10" },
 203         { MARKER_APP11, "Reserved for application segments - 11" },
 204         { MARKER_APP12, "Reserved for application segments - 12" },
 205         { MARKER_APP13, "Reserved for application segments - 13" },
 206         { MARKER_APP14, "Reserved for application segments - 14" },
 207         { MARKER_APP15, "Reserved for application segments - 15" },
 208         { MARKER_JPG0,  "Reserved for JPEG extensions - 0" },
 209         { MARKER_JPG1,  "Reserved for JPEG extensions - 1" },
 210         { MARKER_JPG2,  "Reserved for JPEG extensions - 2" },
 211         { MARKER_JPG3,  "Reserved for JPEG extensions - 3" },
 212         { MARKER_JPG4,  "Reserved for JPEG extensions - 4" },
 213         { MARKER_JPG5,  "Reserved for JPEG extensions - 5" },
 214         { MARKER_JPG6,  "Reserved for JPEG extensions - 6" },
 215         { MARKER_JPG7,  "Reserved for JPEG extensions - 7" },
 216         { MARKER_JPG8,  "Reserved for JPEG extensions - 8" },
 217         { MARKER_JPG9,  "Reserved for JPEG extensions - 9" },
 218         { MARKER_JPG10, "Reserved for JPEG extensions - 10" },
 219         { MARKER_JPG11, "Reserved for JPEG extensions - 11" },
 220         { MARKER_JPG12, "Reserved for JPEG extensions - 12" },
 221         { MARKER_JPG13, "Reserved for JPEG extensions - 13" },
 222         { 0x00, NULL }
 223 };
 224
 225 static const value_string vals_units[] = {
 226         { 0, "No units; Xdensity and Ydensity specify the pixel aspect ratio" },
 227         { 1, "Dots per inch" },
 228         { 2, "Dots per centimeter" },
 229         { 0x00, NULL }
 230 };
 231
 232 static const value_string vals_extension_code[] = {
 233         { 0x10, "Thumbnail encoded using JPEG" },
 234         { 0x11, "Thumbnail encoded using 1 byte (8 bits) per pixel" },
 235         { 0x13, "Thumbnail encoded using 3 bytes (24 bits) per pixel" },
 236         { 0x00, NULL }
 237 };
 238
 239 /* Initialize the protocol and registered fields */
 240 static int proto_jfif = -1;
 241
 242 /* Marker */
 243 static gint hf_marker = -1;
 244 /* Marker segment */
 245 static gint hf_marker_segment = -1;
 246 static gint hf_len = -1;
 247 /* MARKER_APP0 */
 248 static gint hf_identifier = -1;
 249 /* MARKER_APP0 - JFIF */
 250 static gint hf_version = -1;
 251 static gint hf_version_major = -1;
 252 static gint hf_version_minor = -1;
 253 static gint hf_units = -1;
 254 static gint hf_xdensity = -1;
 255 static gint hf_ydensity = -1;
 256 static gint hf_xthumbnail = -1;
 257 static gint hf_ythumbnail = -1;
 258 static gint hf_rgb = -1;
 259 /* MARKER_APP0 - JFXX */
 260 static gint hf_extension_code = -1;
 261 /* start of Frame */
 262 static gint hf_sof_header = -1;
 263 static gint hf_sof_precision = -1;
 264 static gint hf_sof_lines = -1;
 265 static gint hf_sof_samples_per_line = -1;
 266 static gint hf_sof_nf = -1;
 267 static gint hf_sof_c_i = -1;
 268 static gint hf_sof_h_i = -1;
 269 static gint hf_sof_v_i = -1;
 270 static gint hf_sof_tq_i = -1;
 271
 272 /* Start of Scan */
 273 static gint hf_sos_header = -1;
 274 static gint hf_sos_ns = -1;
 275 static gint hf_sos_cs_j = -1;
 276 static gint hf_sos_td_j = -1;
 277 static gint hf_sos_ta_j = -1;
 278 static gint hf_sos_ss = -1;
 279 static gint hf_sos_se = -1;
 280 static gint hf_sos_ah = -1;
 281 static gint hf_sos_al = -1;
 282
 283 /* Initialize the subtree pointers */
 284 static gint ett_jfif = -1;
 285 static gint ett_marker_segment = -1;
 286 static gint ett_details = -1;
 287
 288
 289 /**************** GIF related declarations and definitions ****************/
 290
 291
 292 /************************** Function prototypes **************************/
 293
 294
 295 static void
 296 dissect_jfif(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree);
 297
 298 void
 299 proto_register_jfif(void);
 300
 301
 302
 303 /****************** JFIF protocol dissection functions ******************/
 304
 305 #define ErrorInvalidJFIF "This is not a valid JFIF (JPEG) object"
 306
 307
 308 /*
 309  * Process a marker segment (with length).
 310  */
 311 static void
 312 process_marker_segment(proto_tree *tree, tvbuff_t *tvb, guint32 len,
 313                 guint16 marker, const char *marker_name)
 314 {
 315         proto_item *ti = NULL;
 316         proto_tree *subtree = NULL;
 317
 318         if (! tree)
 319                 return;
 320
 321         ti = proto_tree_add_item(tree, hf_marker_segment,
 322                         tvb, 0, -1, FALSE);
 323         subtree = proto_item_add_subtree(ti, ett_marker_segment);
 324
 325         proto_item_append_text(ti, ": %s (0x%04X)", marker_name, marker);
 326         proto_tree_add_item(subtree, hf_marker, tvb, 0, 2, FALSE);
 327
 328         proto_tree_add_item(subtree, hf_len, tvb, 2, 2, FALSE);
 329
 330         proto_tree_add_text(subtree, tvb, 4, -1,
 331                         "Remaining segment data (%u bytes)", len - 2);
 332 }
 333
 334 /*
 335  * Process a Start of Frame header (with length).
 336  */
 337 static void
 338 process_sof_header(proto_tree *tree, tvbuff_t *tvb, guint32 len _U_,
 339                 guint16 marker, const char *marker_name)
 340 {
 341         proto_item *ti = NULL;
 342         proto_tree *subtree = NULL;
 343
 344         if (! tree)
 345                 return;
 346
 347         ti = proto_tree_add_item(tree, hf_sof_header,
 348                         tvb, 0, -1, FALSE);
 349         subtree = proto_item_add_subtree(ti, ett_marker_segment);
 350
 351         proto_item_append_text(ti, ": %s (0x%04X)", marker_name, marker);
 352         proto_tree_add_item(subtree, hf_marker, tvb, 0, 2, FALSE);
 353
 354         proto_tree_add_item(subtree, hf_len, tvb, 2, 2, FALSE);
 355
 356         proto_tree_add_item(subtree, hf_sof_precision, tvb, 4, 1, FALSE);
 357
 358         proto_tree_add_item(subtree, hf_sof_lines, tvb, 5, 2, FALSE);
 359
 360         proto_tree_add_item(subtree, hf_sof_samples_per_line, tvb, 7, 2, FALSE);
 361
 362         proto_tree_add_item(subtree, hf_sof_nf, tvb, 9, 1, FALSE);
 363         {
 364                 guint8 count = tvb_get_guint8(tvb, 9);
 365                 guint32 offset = 10;
 366                 while (count > 0) {
 367                         proto_tree_add_item(subtree, hf_sof_c_i, tvb, offset++, 1, FALSE);
 368                         proto_tree_add_item(subtree, hf_sof_h_i, tvb, offset, 1, FALSE);
 369                         proto_tree_add_item(subtree, hf_sof_v_i, tvb, offset++, 1, FALSE);
 370                         proto_tree_add_item(subtree, hf_sof_tq_i, tvb, offset++, 1, FALSE);
 371                         count--;
 372                 }
 373         }
 374 }
 375
 376 /*
 377  * Process a Start of Segment header (with length).
 378  */
 379 static void
 380 process_sos_header(proto_tree *tree, tvbuff_t *tvb, guint32 len _U_,
 381                 guint16 marker, const char *marker_name)
 382 {
 383         proto_item *ti = NULL;
 384         proto_tree *subtree = NULL;
 385         guint32 offset;
 386
 387         if (! tree)
 388                 return;
 389
 390         ti = proto_tree_add_item(tree, hf_sos_header,
 391                         tvb, 0, -1, FALSE);
 392         subtree = proto_item_add_subtree(ti, ett_marker_segment);
 393
 394         proto_item_append_text(ti, ": %s (0x%04X)", marker_name, marker);
 395         proto_tree_add_item(subtree, hf_marker, tvb, 0, 2, FALSE);
 396
 397         proto_tree_add_item(subtree, hf_len, tvb, 2, 2, FALSE);
 398
 399         proto_tree_add_item(subtree, hf_sos_ns, tvb, 4, 1, FALSE);
 400         {
 401                 guint8 count = tvb_get_guint8(tvb, 4);
 402                 offset = 5;
 403                 while (count > 0) {
 404                         proto_tree_add_item(subtree, hf_sos_cs_j, tvb, offset++, 1, FALSE);
 405                         proto_tree_add_item(subtree, hf_sos_td_j, tvb, offset, 1, FALSE);
 406                         proto_tree_add_item(subtree, hf_sos_ta_j, tvb, offset++, 1, FALSE);
 407                         count--;
 408                 }
 409         }
 410
 411         proto_tree_add_item(subtree, hf_sos_ss, tvb, offset++, 1, FALSE);
 412         proto_tree_add_item(subtree, hf_sos_se, tvb, offset++, 1, FALSE);
 413
 414         proto_tree_add_item(subtree, hf_sos_ah, tvb, offset, 1, FALSE);
 415         proto_tree_add_item(subtree, hf_sos_al, tvb, offset++, 1, FALSE);
 416 }
 417
 418 /* Process an APP0 block.
 419  *
 420  * XXX - This code only works on US-ASCII systems!!!
 421  */
 422 static void
 423 process_app0_segment(proto_tree *tree, tvbuff_t *tvb, guint32 len,
 424                 guint16 marker, const char *marker_name)
 425 {
 426         proto_item *ti = NULL;
 427         proto_tree *subtree = NULL;
 428         proto_tree *subtree_details = NULL;
 429         guint32 offset;
 430         char *str;
 431         gint str_size;
 432
 433         if (!tree)
 434                 return;
 435
 436         ti = proto_tree_add_item(tree, hf_marker_segment,
 437                         tvb, 0, -1, FALSE);
 438         subtree = proto_item_add_subtree(ti, ett_marker_segment);
 439
 440         proto_item_append_text(ti, ": %s (0x%04X)", marker_name, marker);
 441         proto_tree_add_item(subtree, hf_marker, tvb, 0, 2, FALSE);
 442
 443         proto_tree_add_item(subtree, hf_len, tvb, 2, 2, FALSE);
 444
 445         str = tvb_get_stringz(tvb, 4, &str_size);
 446         ti = proto_tree_add_item(subtree, hf_identifier, tvb, 4, str_size, FALSE);
 447         if (strcmp(str, "JFIF") == 0) {
 448                 /* Version */
 449                 ti = proto_tree_add_none_format(subtree, hf_version,
 450                                 tvb, 9, 2, "Version: %u.%u",
 451                                 tvb_get_guint8(tvb, 9),
 452                                 tvb_get_guint8(tvb, 10));
 453                 subtree_details = proto_item_add_subtree(ti, ett_details);
 454                 proto_tree_add_item(subtree_details, hf_version_major,
 455                                 tvb, 9, 1, FALSE);
 456                 proto_tree_add_item(subtree_details, hf_version_minor,
 457                                 tvb, 10, 1, FALSE);
 458
 459                 proto_tree_add_item(subtree, hf_units,
 460                                 tvb, 11, 1, FALSE);
 461
 462                 /* Aspect ratio */
 463                 proto_tree_add_item(subtree, hf_xdensity,
 464                                 tvb, 12, 2, FALSE);
 465                 proto_tree_add_item(subtree, hf_ydensity,
 466                                 tvb, 14, 2, FALSE);
 467
 468                 /* Thumbnail */
 469                 proto_tree_add_item(subtree, hf_xthumbnail,
 470                                 tvb, 16, 1, FALSE);
 471                 proto_tree_add_item(subtree, hf_ythumbnail,
 472                                 tvb, 17, 1, FALSE);
 473                 {
 474                         guint16 x = tvb_get_guint8(tvb, 16);
 475                         guint16 y = tvb_get_guint8(tvb, 17);
 476                         if (x || y) {
 477                                 proto_tree_add_item(subtree, hf_rgb,
 478                                                 tvb, 18, 3 * (x * y), FALSE);
 479                                 offset = 18 + (3 * (x * y));
 480                         } else {
 481                                 offset = 18;
 482                         }
 483                 }
 484         } else if (strcmp(str, "JFXX") == 0) {
 485                 proto_tree_add_item(subtree, hf_extension_code,
 486                                 tvb, 9, 1, FALSE);
 487                 {
 488                         guint8 code = tvb_get_guint8(tvb, 9);
 489                         switch (code) {
 490                                 case 0x10: /* Thumbnail coded using JPEG */
 491                                         break;
 492                                 case 0x11: /* thumbnail stored using 1 byte per pixel */
 493                                         break;
 494                                 case 0x13: /* thumbnail stored using 3 bytes per pixel */
 495                                         break;
 496                                 default: /* Error */
 497                                         break;
 498                         }
 499                 }
 500         } else { /* Unknown */
 501                 proto_item_append_text(ti, " (unknown identifier)");
 502                 offset = 4 + str_size;
 503
 504                 proto_tree_add_text(subtree, tvb, offset, -1,
 505                                 "Remaining segment data (%u bytes)", len - 2 - str_size);
 506         }
 507
 508         return;
 509 }
 510
 511 static void
 512 dissect_jfif(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree)
 513 {
 514         proto_tree *subtree = NULL;
 515         proto_item *ti;
 516         guint tvb_len = tvb_reported_length(tvb);
 517         guint32 offset = 0;
 518         tvbuff_t *tmp_tvb;
 519         guint32 len;
 520         guint16 marker;
 521
 522         if (tree) {
 523                 ti = proto_tree_add_item(tree, proto_jfif,
 524                                 tvb, 0, -1, FALSE);
 525                 subtree = proto_item_add_subtree(ti, ett_jfif);
 526         }
 527
 528         marker = tvb_get_ntohs(tvb, 0);
 529         if (marker != MARKER_SOI) {
 530                 if (tree) {
 531                         proto_tree_add_text(subtree, tvb, 0, 2, ErrorInvalidJFIF);
 532                         return;
 533                 }
 534         }
 535         if (tree)
 536                 proto_tree_add_item(subtree, hf_marker, tvb, 0, 2, FALSE);
 537
 538         marker = tvb_get_ntohs(tvb, 2);
 539         if (marker != MARKER_APP0) {
 540                 if (tree) {
 541                         proto_tree_add_text(subtree, tvb, 2, 2, ErrorInvalidJFIF);
 542                         return;
 543                 }
 544         }
 545
 546         if (! tree)
 547                 return;
 548
 549         offset = 4;
 550         /* The APP0 segment has a length field */
 551         len = tvb_get_ntohs(tvb, offset);
 552         tmp_tvb = tvb_new_subset(tvb, offset - 2, 2 + len, 2 + len);
 553         process_app0_segment(subtree, tmp_tvb, len, marker,
 554                         match_strval(marker, vals_marker));
 555         offset += len;
 556
 557         /*
 558          * Process the remaining markers and marker segments
 559          */
 560         while (offset < tvb_len) {
 561                 char *str;
 562                 marker = tvb_get_ntohs(tvb, offset);
 563                 str = match_strval(marker, vals_marker);
 564                 if (str) { /* Known marker */
 565                         if (marker_has_length(marker)) { /* Marker segment */
 566                                 /* Length of marker segment = 2 + len */
 567                                 len = tvb_get_ntohs(tvb, offset + 2);
 568                                 tmp_tvb = tvb_new_subset(tvb, offset, 2 + len, 2 + len);
 569                                 switch (marker) {
 570                                         case MARKER_APP0:
 571                                                 process_app0_segment(subtree, tmp_tvb, len, marker, str);
 572                                                 break;
 573                                         case MARKER_SOF0:
 574                                         case MARKER_SOF1:
 575                                         case MARKER_SOF2:
 576                                         case MARKER_SOF3:
 577                                         case MARKER_SOF5:
 578                                         case MARKER_SOF6:
 579                                         case MARKER_SOF7:
 580                                         case MARKER_SOF8:
 581                                         case MARKER_SOF9:
 582                                         case MARKER_SOF10:
 583                                         case MARKER_SOF11:
 584                                         case MARKER_SOF13:
 585                                         case MARKER_SOF14:
 586                                         case MARKER_SOF15:
 587                                                 process_sof_header(subtree, tmp_tvb, len, marker, str);
 588                                                 break;
 589                                         case MARKER_SOS:
 590                                                 process_sos_header(subtree, tmp_tvb, len, marker, str);
 591                                                 /*
 592                                                  * TODO - dissect a scan; the scan data is encoded.
 593                                                  */
 594                                                 proto_tree_add_text(subtree, tvb, offset + 2 + len, -1,
 595                                                                 "JFIF dissection stops here (dissection of a scan is not yet implemented)");
 596                                                 return;
 597                                                 break;
 598                                         default:
 599                                                 process_marker_segment(subtree, tmp_tvb, len, marker, str);
 600                                                 break;
 601                                 }
 602                                 offset += 2 + len;
 603                         } else { /* Marker but no segment */
 604                                 /* Length = 2 */
 605                                 proto_tree_add_item(subtree, hf_marker,
 606                                                 tvb, offset, 2, FALSE);
 607                                 offset += 2;
 608                         }
 609                 } else { /* Reserved! */
 610                         ti = proto_tree_add_item(subtree, hf_marker,
 611                                         tvb, offset, 2, FALSE);
 612                         proto_item_append_text(ti, " (Reserved)");
 613                         return;
 614                 }
 615         }
 616
 617         return;
 618 }
 619
 620
 621 /****************** Register the protocol with Ethereal ******************/
 622
 623
 624 /* This format is required because a script is used to build the C function
 625  * that calls the protocol registration. */
 626
 627 void
 628 proto_register_jfif(void)
 629 {
 630         /*
 631          * Setup list of header fields.
 632          */
 633         static hf_register_info hf[] = {
 634                 /* Marker */
 635                 { &hf_marker,
 636                         {       "Marker",
 637                                 IMG_JFIF ".marker",
 638                                 FT_UINT8, BASE_HEX, VALS(vals_marker), 0x00,
 639                                 "JFIF Marker",
 640                                 HFILL
 641                         }
 642                 },
 643                 /* Marker segment */
 644                 { &hf_marker_segment,
 645                         {       "Marker segment",
 646                                 IMG_JFIF "marker_segment",
 647                                 FT_NONE, BASE_NONE, NULL, 0x00,
 648                                 "Marker segment",
 649                                 HFILL
 650                         }
 651                 },
 652                 { &hf_len,
 653                         {       "Length",
 654                                 IMG_JFIF ".length",
 655                                 FT_UINT16, BASE_DEC, 0, 0x00,
 656                                 "Length of segment (including length field)",
 657                                 HFILL
 658                         }
 659                 },
 660                 /* MARKER_APP0 */
 661                 { &hf_identifier,
 662                         {       "Identifier",
 663                                 IMG_JFIF ".identifier",
 664                                 FT_STRINGZ, BASE_NONE, NULL, 0x00,
 665                                 "Identifier of the segment",
 666                                 HFILL
 667                         }
 668                 },
 669                 /* MARKER_APP0 - JFIF */
 670                 { &hf_version,
 671                         {       "Version",
 672                                 IMG_JFIF ".version",
 673                                 FT_NONE, BASE_NONE, NULL, 0x00,
 674                                 "JFIF Version",
 675                                 HFILL
 676                         }
 677                 },
 678                 { &hf_version_major,
 679                         {       "Major Version",
 680                                 IMG_JFIF ".version.major",
 681                                 FT_UINT8, BASE_DEC, NULL, 0x00,
 682                                 "JFIF Major Version",
 683                                 HFILL
 684                         }
 685                 },
 686                 { &hf_version_minor,
 687                         {       "Minor Version",
 688                                 IMG_JFIF ".version.minor",
 689                                 FT_UINT8, BASE_DEC, NULL, 0x00,
 690                                 "JFIF Minor Version",
 691                                 HFILL
 692                         }
 693                 },
 694                 { &hf_units,
 695                         {       "Units",
 696                                 IMG_JFIF ".units",
 697                                 FT_UINT8, BASE_DEC, VALS(vals_units), 0x00,
 698                                 "Units used in this segment",
 699                                 HFILL
 700                         }
 701                 },
 702                 { &hf_xdensity,
 703                         {       "Xdensity",
 704                                 IMG_JFIF ".Xdensity",
 705                                 FT_UINT16, BASE_DEC, NULL, 0x00,
 706                                 "Horizontal pixel density",
 707                                 HFILL
 708                         }
 709                 },
 710                 { &hf_ydensity,
 711                         {       "Ydensity",
 712                                 IMG_JFIF ".Ydensity",
 713                                 FT_UINT16, BASE_DEC, NULL, 0x00,
 714                                 "Vertical pixel density",
 715                                 HFILL
 716                         }
 717                 },
 718                 { &hf_xthumbnail,
 719                         {       "Xthumbnail",
 720                                 IMG_JFIF ".Xthumbnail",
 721                                 FT_UINT16, BASE_DEC, NULL, 0x00,
 722                                 "Thumbnail horizontal pixel count",
 723                                 HFILL
 724                         }
 725                 },
 726                 { &hf_ythumbnail,
 727                         {       "Ythumbnail",
 728                                 IMG_JFIF ".Ythumbnail",
 729                                 FT_UINT16, BASE_DEC, NULL, 0x00,
 730                                 "Thumbnail vertical pixel count",
 731                                 HFILL
 732                         }
 733                 },
 734                 { &hf_rgb,
 735                         {       "RGB values of thumbnail pixels",
 736                                 IMG_JFIF ".RGB",
 737                                 FT_BYTES, BASE_NONE, NULL, 0x00,
 738                                 "RGB values of the thumbnail pixels (24 bit per pixel, Xthumbnail x Ythumbnail pixels)",
 739                                 HFILL
 740                         }
 741                 },
 742                 /* MARKER_APP0 - JFXX */
 743                 { &hf_extension_code,
 744                         {       "Extension code",
 745                                 IMG_JFIF ".extension.code",
 746                                 FT_UINT8, BASE_HEX, VALS(vals_extension_code), 0x00,
 747                                 "JFXX extension code for thumbnail encoding",
 748                                 HFILL
 749                         }
 750                 },
 751                 /* Header: Start of Frame (MARKER_SOF) */
 752                 { &hf_sof_header,
 753                         {       "Start of Frame header",
 754                                 IMG_JFIF ".sof",
 755                                 FT_NONE, BASE_NONE, NULL, 0x00,
 756                                 "Start of Frame header",
 757                                 HFILL
 758                         }
 759                 },
 760                 { &hf_sof_precision,
 761                         {       "Sample Precision (bits)",
 762                                 IMG_JFIF ".sof.precision",
 763                                 FT_UINT8, BASE_DEC, NULL, 0x00,
 764                                 "Specifies the precision in bits for the samples of the components in the frame.",
 765                                 HFILL
 766                         }
 767                 },
 768                 { &hf_sof_lines,
 769                         {       "Lines",
 770                                 IMG_JFIF ".sof.lines",
 771                                 FT_UINT16, BASE_DEC, NULL, 0x00,
 772                                 "Specifies the maximum number of lines in the source image.",
 773                                 HFILL
 774                         }
 775                 },
 776                 { &hf_sof_samples_per_line,
 777                         {       "Samples per line",
 778                                 IMG_JFIF ".sof.samples_per_line",
 779                                 FT_UINT16, BASE_DEC, NULL, 0x00,
 780                                 "Specifies the maximum number of samples per line in the source image.",
 781                                 HFILL
 782                         }
 783                 },
 784                 { &hf_sof_nf,
 785                         {       "Number of image components in frame",
 786                                 IMG_JFIF ".sof.nf",
 787                                 FT_UINT8, BASE_DEC, NULL, 0x00,
 788                                 "Specifies the number of source image components in the frame.",
 789                                 HFILL
 790                         }
 791                 },
 792                 { &hf_sof_c_i,
 793                         {       "Component identifier",
 794                                 IMG_JFIF ".sof.c_i",
 795                                 FT_UINT8, BASE_DEC, NULL, 0x00,
 796                                 "Assigns a unique label to the ith component in the sequence "
 797                                 "of frame component specification parameters.",
 798                                 HFILL
 799                         }
 800                 },
 801                 { &hf_sof_h_i,
 802                         {       "Horizontal sampling factor",
 803                                 IMG_JFIF ".sof.h_i",
 804                                 FT_UINT8, BASE_DEC, NULL, 0xF0,
 805                                 "Specifies the relationship between the component horizontal "
 806                                 "dimension and maximum image dimension X.",
 807                                 HFILL
 808                         }
 809                 },
 810                 { &hf_sof_v_i,
 811                         {       "Vertical sampling factor",
 812                                 IMG_JFIF ".sof.v_i",
 813                                 FT_UINT8, BASE_DEC, NULL, 0x0F,
 814                                 "Specifies the relationship between the component vertical "
 815                                 "dimension and maximum image dimension Y.",
 816                                 HFILL
 817                         }
 818                 },
 819                 { &hf_sof_tq_i,
 820                         {       "Quantization table destination selector",
 821                                 IMG_JFIF ".sof.tq_i",
 822                                 FT_UINT8, BASE_DEC, NULL, 0x00,
 823                                 "Specifies one of four possible quantization table "
 824                                 "destinations from which the quantization table to use "
 825                                 "for dequantization of DCT coefficients of component Ci "
 826                                 "is retrieved.",
 827                                 HFILL
 828                         }
 829                 },
 830
 831                 /* Header: Start of Segment (MARKER_SOS) */
 832                 { &hf_sos_header,
 833                         {       "Start of Segment header",
 834                                 IMG_JFIF ".header.sos",
 835                                 FT_NONE, BASE_NONE, NULL, 0x00,
 836                                 "Start of Segment header",
 837                                 HFILL
 838                         }
 839                 },
 840                 { &hf_sos_ns,
 841                         {       "Number of image components in scan",
 842                                 IMG_JFIF ".sos.ns",
 843                                 FT_UINT8, BASE_DEC, NULL, 0x00,
 844                                 "Specifies the number of source image components in the scan.",
 845                                 HFILL
 846                         }
 847                 },
 848                 { &hf_sos_cs_j,
 849                         {       "Scan component selector",
 850                                 IMG_JFIF ".sos.component_selector",
 851                                 FT_UINT8, BASE_DEC, NULL, 0x00,
 852                                 "Selects which of the Nf image components specified in the "
 853                                 "frame parameters shall be the jth component in the scan.",
 854                                 HFILL
 855                         }
 856                 },
 857                 { &hf_sos_td_j,
 858                         {       "DC entropy coding table destination selector",
 859                                 IMG_JFIF ".sos.dc_entropy_selector",
 860                                 FT_UINT8, BASE_DEC, NULL, 0xF0,
 861                                 "Specifies one of four possible DC entropy coding table "
 862                                 "destinations from which the entropy table needed "
 863                                 "for decoding of the DC coefficients of component Csj "
 864                                 "is retrieved.",
 865                                 HFILL
 866                         }
 867                 },
 868                 { &hf_sos_ta_j,
 869                         {       "AC entropy coding table destination selector",
 870                                 IMG_JFIF ".sos.ac_entropy_selector",
 871                                 FT_UINT8, BASE_DEC, NULL, 0x0F,
 872                                 "Specifies one of four possible AC entropy coding table "
 873                                 "destinations from which the entropy table needed "
 874                                 "for decoding of the AC coefficients of component Csj "
 875                                 "is retrieved.",
 876                                 HFILL
 877                         }
 878                 },
 879                 { &hf_sos_ss,
 880                         {       "Start of spectral or predictor selection",
 881                                 IMG_JFIF ".sos.ss",
 882                                 FT_UINT8, BASE_DEC, NULL, 0x00,
 883                                 "In the DCT modes of operation, this parameter specifies the "
 884                                 "first DCT coefficient in each block in zig-zag order which "
 885                                 "shall be coded in the scan. This parameter shall be set to "
 886                                 "zero for the sequential DCT processes. "
 887                                 "In the lossless mode of operations this parameter is used "
 888                                 "to select the predictor.",
 889                                 HFILL
 890                         }
 891                 },
 892                 { &hf_sos_se,
 893                         {       "End of spectral selection",
 894                                 IMG_JFIF ".sos.se",
 895                                 FT_UINT8, BASE_DEC, NULL, 0x00,
 896                                 "Specifies the last DCT coefficient in each block in zig-zag "
 897                                 "order which shall be coded in the scan. This parameter shall "
 898                                 "be set to 63 for the sequential DCT processes. "
 899                                 "In the lossless mode of operations this parameter has no "
 900                                 "meaning. It shall be set to zero.",
 901                                 HFILL
 902                         }
 903                 },
 904                 { &hf_sos_ah,
 905                         {       "Successive approximation bit position high",
 906                                 IMG_JFIF ".sos.ah",
 907                                 FT_UINT8, BASE_DEC, NULL, 0xF0,
 908                                 "This parameter specifies the point transform used in the "
 909                                 "preceding scan (i.e. successive approximation bit position "
 910                                 "low in the preceding scan) for the band of coefficients "
 911                                 "specified by Ss and Se. This parameter shall be set to zero "
 912                                 "for the first scan of each band of coefficients. "
 913                                 "In the lossless mode of operations this parameter has no "
 914                                 "meaning. It shall be set to zero.",
 915                                 HFILL
 916                         }
 917                 },
 918                 { &hf_sos_al,
 919                         {       "Successive approximation bit position low or point transform",
 920                                 IMG_JFIF ".sos.al",
 921                                 FT_UINT8, BASE_DEC, NULL, 0x0F,
 922                                 "In the DCT modes of operation this parameter specifies the "
 923                                 "point transform, i.e. bit position low, used before coding "
 924                                 "the band of coefficients specified by Ss and Se. "
 925                                 "This parameter shall be set to zero for the sequential DCT "
 926                                 "processes. In the lossless mode of operations, this "
 927                                 "parameter specifies the point transform, Pt.",
 928                                 HFILL
 929                         }
 930                 },
 931         };
 932
 933         /* Setup protocol subtree array */
 934         static gint *ett[] = {
 935                 &ett_jfif,
 936                 &ett_marker_segment,
 937                 &ett_details,
 938         };
 939
 940         /* Register the protocol name and description */
 941         proto_jfif = proto_register_protocol(
 942                         "JPEG File Interchange Format",
 943                         "JFIF (JPEG) image",
 944                         IMG_JFIF
 945         );
 946
 947         /* Required function calls to register the header fields
 948          * and subtrees used */
 949         proto_register_field_array(proto_jfif, hf, array_length(hf));
 950         proto_register_subtree_array(ett, array_length(ett));
 951
 952         register_dissector("image-jfif", dissect_jfif, proto_jfif);
 953 }
 954
 955
 956 void
 957 proto_reg_handoff_jfif(void)
 958 {
 959         dissector_handle_t jfif_handle;
 960
 961         jfif_handle = create_dissector_handle(dissect_jfif, proto_jfif);
 962
 963         /* Register the GIF media type */
 964         dissector_add_string("media_type", "image/jfif", jfif_handle);
 965         dissector_add_string("media_type", "image/jpg", jfif_handle);
 966         dissector_add_string("media_type", "image/jpeg", jfif_handle);
 967 }