/* packet-image-jfif.c * * Routines for JFIF image/jpeg media dissection * Copyright 2004, Olivier Biot. * * $Id: packet-image-jfif.c,v 1.4 2004/03/08 22:03:58 obiot Exp $ * * Refer to the AUTHORS file or the AUTHORS section in the man page * for contacting the author(s) of this file. * * Ethereal - Network traffic analyzer * By Gerald Combs * Copyright 1998 Gerald Combs * * JFIF media decoding functionality provided by Olivier Biot. * * The JFIF specifications are found at several locations, such as: * http://www.jpeg.org/public/jfif.pdf * http://www.w3.org/Graphics/JPEG/itu-t81.pdf * * 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. */ /* Edit this file with 4-space tabulation */ #ifdef HAVE_CONFIG_H # include "config.h" #endif #include #include #include #include #ifdef NEED_SNPRINTF_H # include "snprintf.h" #endif #include /* General-purpose debug logger. * Requires double parentheses because of variable arguments of printf(). * * Enable debug logging for JFIF by defining AM_CFLAGS * so that it contains "-DDEBUG_image_jfif" or "-DDEBUG_image" */ #if (defined(DEBUG_image_jfif) || defined(DEBUG_image)) #define DebugLog(x) \ printf("%s:%u: ", __FILE__, __LINE__); \ printf x; \ fflush(stdout) #else #define DebugLog(x) ; #endif #define PLURALIZE(x) ((x) == 1 ? "" : "s") #define IMG_JFIF "image-jfif" /************************** Variable declarations **************************/ #define MARKER_TEM 0xFF01 /* 0xFF02 -- 0xFFBF are reserved */ #define MARKER_SOF0 0xFFC0 #define MARKER_SOF1 0xFFC1 #define MARKER_SOF2 0xFFC2 #define MARKER_SOF3 0xFFC3 #define MARKER_DHT 0xFFC4 #define MARKER_SOF5 0xFFC5 #define MARKER_SOF6 0xFFC6 #define MARKER_SOF7 0xFFC7 #define MARKER_SOF8 0xFFC8 #define MARKER_SOF9 0xFFC9 #define MARKER_SOF10 0xFFCA #define MARKER_SOF11 0xFFCB #define MARKER_DAC 0xFFCC #define MARKER_SOF13 0xFFCD #define MARKER_SOF14 0xFFCE #define MARKER_SOF15 0xFFCF #define MARKER_RST0 0xFFD0 #define MARKER_RST1 0xFFD1 #define MARKER_RST2 0xFFD2 #define MARKER_RST3 0xFFD3 #define MARKER_RST4 0xFFD4 #define MARKER_RST5 0xFFD5 #define MARKER_RST6 0xFFD6 #define MARKER_RST7 0xFFD7 #define MARKER_FFDB 0xFFDB #define MARKER_SOI 0xFFD8 #define MARKER_EOI 0xFFD9 #define MARKER_SOS 0xFFDA #define MARKER_DQT 0xFFDB #define MARKER_DNL 0xFFDC #define MARKER_DRI 0xFFDD #define MARKER_DHP 0xFFDE #define MARKER_EXP 0xFFDF #define MARKER_APP0 0xFFE0 #define MARKER_APP1 0xFFE1 #define MARKER_APP2 0xFFE2 #define MARKER_APP3 0xFFE3 #define MARKER_APP4 0xFFE4 #define MARKER_APP5 0xFFE5 #define MARKER_APP6 0xFFE6 #define MARKER_APP7 0xFFE7 #define MARKER_APP8 0xFFE8 #define MARKER_APP9 0xFFE9 #define MARKER_APP10 0xFFEA #define MARKER_APP11 0xFFEB #define MARKER_APP12 0xFFEC #define MARKER_APP13 0xFFED #define MARKER_APP14 0xFFEE #define MARKER_APP15 0xFFEF #define MARKER_JPG0 0xFFF0 #define MARKER_JPG1 0xFFF1 #define MARKER_JPG2 0xFFF2 #define MARKER_JPG3 0xFFF3 #define MARKER_JPG4 0xFFF4 #define MARKER_JPG5 0xFFF5 #define MARKER_JPG6 0xFFF6 #define MARKER_JPG7 0xFFF7 #define MARKER_JPG8 0xFFF8 #define MARKER_JPG9 0xFFF9 #define MARKER_JPG10 0xFFFA #define MARKER_JPG11 0xFFFB #define MARKER_JPG12 0xFFFC #define MARKER_JPG13 0xFFFD #define MARKER_COM 0xFFFE #define marker_has_length(marker) ( ! ( \ ((marker) == MARKER_TEM) \ || ((marker) == MARKER_SOI) \ || ((marker) == MARKER_EOI) \ || ( ((marker) >= MARKER_RST0) && ((marker) <= MARKER_RST7) ) \ ) ) static const value_string vals_marker[] = { { MARKER_TEM, "Reserved - For temporary private use in arithmetic coding" }, { MARKER_SOF0, "Start of Frame (non-differential, Huffman coding) - Baseline DCT" }, { MARKER_SOF1, "Start of Frame (non-differential, Huffman coding) - Extended sequential DCT" }, { MARKER_SOF2, "Start of Frame (non-differential, Huffman coding) - Progressive DCT" }, { MARKER_SOF3, "Start of Frame (non-differential, Huffman coding) - Lossless (sequential)" }, { MARKER_DHT, "Define Huffman table(s)" }, { MARKER_SOF5, "Start of Frame (differential, Huffman coding) - Differential sequential DCT" }, { MARKER_SOF6, "Start of Frame (differential, Huffman coding) - Differential progressive DCT" }, { MARKER_SOF7, "Start of Frame (differential, Huffman coding) - Differential lossless (sequential)" }, { MARKER_SOF8, "Start of Frame (non-differential, arithmetic coding) - Reserved for JPEG extensions" }, { MARKER_SOF9, "Start of Frame (non-differential, arithmetic coding) - Extended sequential DCT" }, { MARKER_SOF10, "Start of Frame (non-differential, arithmetic coding) - Progressive DCT" }, { MARKER_SOF11, "Start of Frame (non-differential, arithmetic coding) - Lossless (sequential)" }, { MARKER_DAC, "Define arithmetic coding conditioning(s)" }, { MARKER_SOF13, "Start of Frame (differential, arithmetic coding) - Differential sequential DCT" }, { MARKER_SOF14, "Start of Frame (differential, arithmetic coding) - Differential progressive DCT" }, { MARKER_SOF15, "Start of Frame (differential, arithmetic coding) - Differential lossless (sequential)" }, { MARKER_RST0, "Restart interval termination - Restart with modulo 8 count 0" }, { MARKER_RST1, "Restart interval termination - Restart with modulo 8 count 1" }, { MARKER_RST2, "Restart interval termination - Restart with modulo 8 count 2" }, { MARKER_RST3, "Restart interval termination - Restart with modulo 8 count 3" }, { MARKER_RST4, "Restart interval termination - Restart with modulo 8 count 4" }, { MARKER_RST5, "Restart interval termination - Restart with modulo 8 count 5" }, { MARKER_RST6, "Restart interval termination - Restart with modulo 8 count 6" }, { MARKER_RST7, "Restart interval termination - Restart with modulo 8 count 7" }, { MARKER_SOI, "Start of Image" }, { MARKER_EOI, "End of Image" }, { MARKER_SOS, "Start of Scan" }, { MARKER_DQT, "Define quantization table(s)" }, { MARKER_DNL, "Define number of lines" }, { MARKER_DRI, "Define restart interval" }, { MARKER_DHP, "Define hierarchical progression" }, { MARKER_EXP, "Expand reference component(s)" }, { MARKER_APP0, "Reserved for application segments - 0" }, { MARKER_APP1, "Reserved for application segments - 1" }, { MARKER_APP2, "Reserved for application segments - 2" }, { MARKER_APP3, "Reserved for application segments - 3" }, { MARKER_APP4, "Reserved for application segments - 4" }, { MARKER_APP5, "Reserved for application segments - 5" }, { MARKER_APP6, "Reserved for application segments - 6" }, { MARKER_APP7, "Reserved for application segments - 7" }, { MARKER_APP8, "Reserved for application segments - 8" }, { MARKER_APP9, "Reserved for application segments - 9" }, { MARKER_APP10, "Reserved for application segments - 10" }, { MARKER_APP11, "Reserved for application segments - 11" }, { MARKER_APP12, "Reserved for application segments - 12" }, { MARKER_APP13, "Reserved for application segments - 13" }, { MARKER_APP14, "Reserved for application segments - 14" }, { MARKER_APP15, "Reserved for application segments - 15" }, { MARKER_JPG0, "Reserved for JPEG extensions - 0" }, { MARKER_JPG1, "Reserved for JPEG extensions - 1" }, { MARKER_JPG2, "Reserved for JPEG extensions - 2" }, { MARKER_JPG3, "Reserved for JPEG extensions - 3" }, { MARKER_JPG4, "Reserved for JPEG extensions - 4" }, { MARKER_JPG5, "Reserved for JPEG extensions - 5" }, { MARKER_JPG6, "Reserved for JPEG extensions - 6" }, { MARKER_JPG7, "Reserved for JPEG extensions - 7" }, { MARKER_JPG8, "Reserved for JPEG extensions - 8" }, { MARKER_JPG9, "Reserved for JPEG extensions - 9" }, { MARKER_JPG10, "Reserved for JPEG extensions - 10" }, { MARKER_JPG11, "Reserved for JPEG extensions - 11" }, { MARKER_JPG12, "Reserved for JPEG extensions - 12" }, { MARKER_JPG13, "Reserved for JPEG extensions - 13" }, { 0x00, NULL } }; static const value_string vals_units[] = { { 0, "No units; Xdensity and Ydensity specify the pixel aspect ratio" }, { 1, "Dots per inch" }, { 2, "Dots per centimeter" }, { 0x00, NULL } }; static const value_string vals_extension_code[] = { { 0x10, "Thumbnail encoded using JPEG" }, { 0x11, "Thumbnail encoded using 1 byte (8 bits) per pixel" }, { 0x13, "Thumbnail encoded using 3 bytes (24 bits) per pixel" }, { 0x00, NULL } }; /* Initialize the protocol and registered fields */ static int proto_jfif = -1; /* Marker */ static gint hf_marker = -1; /* Marker segment */ static gint hf_marker_segment = -1; static gint hf_len = -1; /* MARKER_APP0 */ static gint hf_identifier = -1; /* MARKER_APP0 - JFIF */ static gint hf_version = -1; static gint hf_version_major = -1; static gint hf_version_minor = -1; static gint hf_units = -1; static gint hf_xdensity = -1; static gint hf_ydensity = -1; static gint hf_xthumbnail = -1; static gint hf_ythumbnail = -1; static gint hf_rgb = -1; /* MARKER_APP0 - JFXX */ static gint hf_extension_code = -1; /* start of Frame */ static gint hf_sof_header = -1; static gint hf_sof_precision = -1; static gint hf_sof_lines = -1; static gint hf_sof_samples_per_line = -1; static gint hf_sof_nf = -1; static gint hf_sof_c_i = -1; static gint hf_sof_h_i = -1; static gint hf_sof_v_i = -1; static gint hf_sof_tq_i = -1; /* Start of Scan */ static gint hf_sos_header = -1; static gint hf_sos_ns = -1; static gint hf_sos_cs_j = -1; static gint hf_sos_td_j = -1; static gint hf_sos_ta_j = -1; static gint hf_sos_ss = -1; static gint hf_sos_se = -1; static gint hf_sos_ah = -1; static gint hf_sos_al = -1; /* Initialize the subtree pointers */ static gint ett_jfif = -1; static gint ett_marker_segment = -1; static gint ett_details = -1; /**************** GIF related declarations and definitions ****************/ /************************** Function prototypes **************************/ static void dissect_jfif(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree); void proto_register_jfif(void); /****************** JFIF protocol dissection functions ******************/ #define ErrorInvalidJFIF "This is not a valid JFIF (JPEG) object" /* * Process a marker segment (with length). */ static void process_marker_segment(proto_tree *tree, tvbuff_t *tvb, guint32 len, guint16 marker, const char *marker_name) { proto_item *ti = NULL; proto_tree *subtree = NULL; if (! tree) return; ti = proto_tree_add_item(tree, hf_marker_segment, tvb, 0, -1, FALSE); subtree = proto_item_add_subtree(ti, ett_marker_segment); proto_item_append_text(ti, ": %s (0x%04X)", marker_name, marker); proto_tree_add_item(subtree, hf_marker, tvb, 0, 2, FALSE); proto_tree_add_item(subtree, hf_len, tvb, 2, 2, FALSE); proto_tree_add_text(subtree, tvb, 4, -1, "Remaining segment data (%u bytes)", len - 2); } /* * Process a Start of Frame header (with length). */ static void process_sof_header(proto_tree *tree, tvbuff_t *tvb, guint32 len _U_, guint16 marker, const char *marker_name) { proto_item *ti = NULL; proto_tree *subtree = NULL; if (! tree) return; ti = proto_tree_add_item(tree, hf_sof_header, tvb, 0, -1, FALSE); subtree = proto_item_add_subtree(ti, ett_marker_segment); proto_item_append_text(ti, ": %s (0x%04X)", marker_name, marker); proto_tree_add_item(subtree, hf_marker, tvb, 0, 2, FALSE); proto_tree_add_item(subtree, hf_len, tvb, 2, 2, FALSE); proto_tree_add_item(subtree, hf_sof_precision, tvb, 4, 1, FALSE); proto_tree_add_item(subtree, hf_sof_lines, tvb, 5, 2, FALSE); proto_tree_add_item(subtree, hf_sof_samples_per_line, tvb, 7, 2, FALSE); proto_tree_add_item(subtree, hf_sof_nf, tvb, 9, 1, FALSE); { guint8 count = tvb_get_guint8(tvb, 9); guint32 offset = 10; while (count > 0) { proto_tree_add_item(subtree, hf_sof_c_i, tvb, offset++, 1, FALSE); proto_tree_add_item(subtree, hf_sof_h_i, tvb, offset, 1, FALSE); proto_tree_add_item(subtree, hf_sof_v_i, tvb, offset++, 1, FALSE); proto_tree_add_item(subtree, hf_sof_tq_i, tvb, offset++, 1, FALSE); count--; } } } /* * Process a Start of Segment header (with length). */ static void process_sos_header(proto_tree *tree, tvbuff_t *tvb, guint32 len _U_, guint16 marker, const char *marker_name) { proto_item *ti = NULL; proto_tree *subtree = NULL; guint32 offset; if (! tree) return; ti = proto_tree_add_item(tree, hf_sos_header, tvb, 0, -1, FALSE); subtree = proto_item_add_subtree(ti, ett_marker_segment); proto_item_append_text(ti, ": %s (0x%04X)", marker_name, marker); proto_tree_add_item(subtree, hf_marker, tvb, 0, 2, FALSE); proto_tree_add_item(subtree, hf_len, tvb, 2, 2, FALSE); proto_tree_add_item(subtree, hf_sos_ns, tvb, 4, 1, FALSE); { guint8 count = tvb_get_guint8(tvb, 4); offset = 5; while (count > 0) { proto_tree_add_item(subtree, hf_sos_cs_j, tvb, offset++, 1, FALSE); proto_tree_add_item(subtree, hf_sos_td_j, tvb, offset, 1, FALSE); proto_tree_add_item(subtree, hf_sos_ta_j, tvb, offset++, 1, FALSE); count--; } } proto_tree_add_item(subtree, hf_sos_ss, tvb, offset++, 1, FALSE); proto_tree_add_item(subtree, hf_sos_se, tvb, offset++, 1, FALSE); proto_tree_add_item(subtree, hf_sos_ah, tvb, offset, 1, FALSE); proto_tree_add_item(subtree, hf_sos_al, tvb, offset++, 1, FALSE); } /* Process an APP0 block. * * XXX - This code only works on US-ASCII systems!!! */ static void process_app0_segment(proto_tree *tree, tvbuff_t *tvb, guint32 len, guint16 marker, const char *marker_name) { proto_item *ti = NULL; proto_tree *subtree = NULL; proto_tree *subtree_details = NULL; guint32 offset; char *str; gint str_size; if (!tree) return; ti = proto_tree_add_item(tree, hf_marker_segment, tvb, 0, -1, FALSE); subtree = proto_item_add_subtree(ti, ett_marker_segment); proto_item_append_text(ti, ": %s (0x%04X)", marker_name, marker); proto_tree_add_item(subtree, hf_marker, tvb, 0, 2, FALSE); proto_tree_add_item(subtree, hf_len, tvb, 2, 2, FALSE); str = tvb_get_stringz(tvb, 4, &str_size); ti = proto_tree_add_item(subtree, hf_identifier, tvb, 4, str_size, FALSE); if (strcmp(str, "JFIF") == 0) { /* Version */ ti = proto_tree_add_none_format(subtree, hf_version, tvb, 9, 2, "Version: %u.%u", tvb_get_guint8(tvb, 9), tvb_get_guint8(tvb, 10)); subtree_details = proto_item_add_subtree(ti, ett_details); proto_tree_add_item(subtree_details, hf_version_major, tvb, 9, 1, FALSE); proto_tree_add_item(subtree_details, hf_version_minor, tvb, 10, 1, FALSE); proto_tree_add_item(subtree, hf_units, tvb, 11, 1, FALSE); /* Aspect ratio */ proto_tree_add_item(subtree, hf_xdensity, tvb, 12, 2, FALSE); proto_tree_add_item(subtree, hf_ydensity, tvb, 14, 2, FALSE); /* Thumbnail */ proto_tree_add_item(subtree, hf_xthumbnail, tvb, 16, 1, FALSE); proto_tree_add_item(subtree, hf_ythumbnail, tvb, 17, 1, FALSE); { guint16 x = tvb_get_guint8(tvb, 16); guint16 y = tvb_get_guint8(tvb, 17); if (x || y) { proto_tree_add_item(subtree, hf_rgb, tvb, 18, 3 * (x * y), FALSE); offset = 18 + (3 * (x * y)); } else { offset = 18; } } } else if (strcmp(str, "JFXX") == 0) { proto_tree_add_item(subtree, hf_extension_code, tvb, 9, 1, FALSE); { guint8 code = tvb_get_guint8(tvb, 9); switch (code) { case 0x10: /* Thumbnail coded using JPEG */ break; case 0x11: /* thumbnail stored using 1 byte per pixel */ break; case 0x13: /* thumbnail stored using 3 bytes per pixel */ break; default: /* Error */ break; } } } else { /* Unknown */ proto_item_append_text(ti, " (unknown identifier)"); offset = 4 + str_size; proto_tree_add_text(subtree, tvb, offset, -1, "Remaining segment data (%u bytes)", len - 2 - str_size); } return; } static void dissect_jfif(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree) { proto_tree *subtree = NULL; proto_item *ti; guint tvb_len = tvb_reported_length(tvb); guint32 offset = 0; tvbuff_t *tmp_tvb; guint32 len; guint16 marker; /* Add summary to INFO column if it is enabled */ if (check_col(pinfo->cinfo, COL_INFO)) col_append_sep_fstr(pinfo->cinfo, COL_INFO, " ", "(JPEG JFIF image)"); if (tree) { ti = proto_tree_add_item(tree, proto_jfif, tvb, 0, -1, FALSE); subtree = proto_item_add_subtree(ti, ett_jfif); } marker = tvb_get_ntohs(tvb, 0); if (marker != MARKER_SOI) { if (tree) { proto_tree_add_text(subtree, tvb, 0, 2, ErrorInvalidJFIF); return; } } if (tree) proto_tree_add_item(subtree, hf_marker, tvb, 0, 2, FALSE); marker = tvb_get_ntohs(tvb, 2); if (marker != MARKER_APP0) { if (tree) { proto_tree_add_text(subtree, tvb, 2, 2, ErrorInvalidJFIF); return; } } if (! tree) return; offset = 4; /* The APP0 segment has a length field */ len = tvb_get_ntohs(tvb, offset); tmp_tvb = tvb_new_subset(tvb, offset - 2, 2 + len, 2 + len); process_app0_segment(subtree, tmp_tvb, len, marker, match_strval(marker, vals_marker)); offset += len; /* * Process the remaining markers and marker segments */ while (offset < tvb_len) { char *str; marker = tvb_get_ntohs(tvb, offset); str = match_strval(marker, vals_marker); if (str) { /* Known marker */ if (marker_has_length(marker)) { /* Marker segment */ /* Length of marker segment = 2 + len */ len = tvb_get_ntohs(tvb, offset + 2); tmp_tvb = tvb_new_subset(tvb, offset, 2 + len, 2 + len); switch (marker) { case MARKER_APP0: process_app0_segment(subtree, tmp_tvb, len, marker, str); break; case MARKER_SOF0: case MARKER_SOF1: case MARKER_SOF2: case MARKER_SOF3: case MARKER_SOF5: case MARKER_SOF6: case MARKER_SOF7: case MARKER_SOF8: case MARKER_SOF9: case MARKER_SOF10: case MARKER_SOF11: case MARKER_SOF13: case MARKER_SOF14: case MARKER_SOF15: process_sof_header(subtree, tmp_tvb, len, marker, str); break; case MARKER_SOS: process_sos_header(subtree, tmp_tvb, len, marker, str); /* * TODO - dissect a scan; the scan data is encoded. */ proto_tree_add_text(subtree, tvb, offset + 2 + len, -1, "JFIF dissection stops here (dissection of a scan is not yet implemented)"); return; break; default: process_marker_segment(subtree, tmp_tvb, len, marker, str); break; } offset += 2 + len; } else { /* Marker but no segment */ /* Length = 2 */ proto_tree_add_item(subtree, hf_marker, tvb, offset, 2, FALSE); offset += 2; } } else { /* Reserved! */ ti = proto_tree_add_item(subtree, hf_marker, tvb, offset, 2, FALSE); proto_item_append_text(ti, " (Reserved)"); return; } } return; } /****************** Register the protocol with Ethereal ******************/ /* This format is required because a script is used to build the C function * that calls the protocol registration. */ void proto_register_jfif(void) { /* * Setup list of header fields. */ static hf_register_info hf[] = { /* Marker */ { &hf_marker, { "Marker", IMG_JFIF ".marker", FT_UINT8, BASE_HEX, VALS(vals_marker), 0x00, "JFIF Marker", HFILL } }, /* Marker segment */ { &hf_marker_segment, { "Marker segment", IMG_JFIF "marker_segment", FT_NONE, BASE_NONE, NULL, 0x00, "Marker segment", HFILL } }, { &hf_len, { "Length", IMG_JFIF ".length", FT_UINT16, BASE_DEC, 0, 0x00, "Length of segment (including length field)", HFILL } }, /* MARKER_APP0 */ { &hf_identifier, { "Identifier", IMG_JFIF ".identifier", FT_STRINGZ, BASE_NONE, NULL, 0x00, "Identifier of the segment", HFILL } }, /* MARKER_APP0 - JFIF */ { &hf_version, { "Version", IMG_JFIF ".version", FT_NONE, BASE_NONE, NULL, 0x00, "JFIF Version", HFILL } }, { &hf_version_major, { "Major Version", IMG_JFIF ".version.major", FT_UINT8, BASE_DEC, NULL, 0x00, "JFIF Major Version", HFILL } }, { &hf_version_minor, { "Minor Version", IMG_JFIF ".version.minor", FT_UINT8, BASE_DEC, NULL, 0x00, "JFIF Minor Version", HFILL } }, { &hf_units, { "Units", IMG_JFIF ".units", FT_UINT8, BASE_DEC, VALS(vals_units), 0x00, "Units used in this segment", HFILL } }, { &hf_xdensity, { "Xdensity", IMG_JFIF ".Xdensity", FT_UINT16, BASE_DEC, NULL, 0x00, "Horizontal pixel density", HFILL } }, { &hf_ydensity, { "Ydensity", IMG_JFIF ".Ydensity", FT_UINT16, BASE_DEC, NULL, 0x00, "Vertical pixel density", HFILL } }, { &hf_xthumbnail, { "Xthumbnail", IMG_JFIF ".Xthumbnail", FT_UINT16, BASE_DEC, NULL, 0x00, "Thumbnail horizontal pixel count", HFILL } }, { &hf_ythumbnail, { "Ythumbnail", IMG_JFIF ".Ythumbnail", FT_UINT16, BASE_DEC, NULL, 0x00, "Thumbnail vertical pixel count", HFILL } }, { &hf_rgb, { "RGB values of thumbnail pixels", IMG_JFIF ".RGB", FT_BYTES, BASE_NONE, NULL, 0x00, "RGB values of the thumbnail pixels (24 bit per pixel, Xthumbnail x Ythumbnail pixels)", HFILL } }, /* MARKER_APP0 - JFXX */ { &hf_extension_code, { "Extension code", IMG_JFIF ".extension.code", FT_UINT8, BASE_HEX, VALS(vals_extension_code), 0x00, "JFXX extension code for thumbnail encoding", HFILL } }, /* Header: Start of Frame (MARKER_SOF) */ { &hf_sof_header, { "Start of Frame header", IMG_JFIF ".sof", FT_NONE, BASE_NONE, NULL, 0x00, "Start of Frame header", HFILL } }, { &hf_sof_precision, { "Sample Precision (bits)", IMG_JFIF ".sof.precision", FT_UINT8, BASE_DEC, NULL, 0x00, "Specifies the precision in bits for the samples of the components in the frame.", HFILL } }, { &hf_sof_lines, { "Lines", IMG_JFIF ".sof.lines", FT_UINT16, BASE_DEC, NULL, 0x00, "Specifies the maximum number of lines in the source image.", HFILL } }, { &hf_sof_samples_per_line, { "Samples per line", IMG_JFIF ".sof.samples_per_line", FT_UINT16, BASE_DEC, NULL, 0x00, "Specifies the maximum number of samples per line in the source image.", HFILL } }, { &hf_sof_nf, { "Number of image components in frame", IMG_JFIF ".sof.nf", FT_UINT8, BASE_DEC, NULL, 0x00, "Specifies the number of source image components in the frame.", HFILL } }, { &hf_sof_c_i, { "Component identifier", IMG_JFIF ".sof.c_i", FT_UINT8, BASE_DEC, NULL, 0x00, "Assigns a unique label to the ith component in the sequence " "of frame component specification parameters.", HFILL } }, { &hf_sof_h_i, { "Horizontal sampling factor", IMG_JFIF ".sof.h_i", FT_UINT8, BASE_DEC, NULL, 0xF0, "Specifies the relationship between the component horizontal " "dimension and maximum image dimension X.", HFILL } }, { &hf_sof_v_i, { "Vertical sampling factor", IMG_JFIF ".sof.v_i", FT_UINT8, BASE_DEC, NULL, 0x0F, "Specifies the relationship between the component vertical " "dimension and maximum image dimension Y.", HFILL } }, { &hf_sof_tq_i, { "Quantization table destination selector", IMG_JFIF ".sof.tq_i", FT_UINT8, BASE_DEC, NULL, 0x00, "Specifies one of four possible quantization table " "destinations from which the quantization table to use " "for dequantization of DCT coefficients of component Ci " "is retrieved.", HFILL } }, /* Header: Start of Segment (MARKER_SOS) */ { &hf_sos_header, { "Start of Segment header", IMG_JFIF ".header.sos", FT_NONE, BASE_NONE, NULL, 0x00, "Start of Segment header", HFILL } }, { &hf_sos_ns, { "Number of image components in scan", IMG_JFIF ".sos.ns", FT_UINT8, BASE_DEC, NULL, 0x00, "Specifies the number of source image components in the scan.", HFILL } }, { &hf_sos_cs_j, { "Scan component selector", IMG_JFIF ".sos.component_selector", FT_UINT8, BASE_DEC, NULL, 0x00, "Selects which of the Nf image components specified in the " "frame parameters shall be the jth component in the scan.", HFILL } }, { &hf_sos_td_j, { "DC entropy coding table destination selector", IMG_JFIF ".sos.dc_entropy_selector", FT_UINT8, BASE_DEC, NULL, 0xF0, "Specifies one of four possible DC entropy coding table " "destinations from which the entropy table needed " "for decoding of the DC coefficients of component Csj " "is retrieved.", HFILL } }, { &hf_sos_ta_j, { "AC entropy coding table destination selector", IMG_JFIF ".sos.ac_entropy_selector", FT_UINT8, BASE_DEC, NULL, 0x0F, "Specifies one of four possible AC entropy coding table " "destinations from which the entropy table needed " "for decoding of the AC coefficients of component Csj " "is retrieved.", HFILL } }, { &hf_sos_ss, { "Start of spectral or predictor selection", IMG_JFIF ".sos.ss", FT_UINT8, BASE_DEC, NULL, 0x00, "In the DCT modes of operation, this parameter specifies the " "first DCT coefficient in each block in zig-zag order which " "shall be coded in the scan. This parameter shall be set to " "zero for the sequential DCT processes. " "In the lossless mode of operations this parameter is used " "to select the predictor.", HFILL } }, { &hf_sos_se, { "End of spectral selection", IMG_JFIF ".sos.se", FT_UINT8, BASE_DEC, NULL, 0x00, "Specifies the last DCT coefficient in each block in zig-zag " "order which shall be coded in the scan. This parameter shall " "be set to 63 for the sequential DCT processes. " "In the lossless mode of operations this parameter has no " "meaning. It shall be set to zero.", HFILL } }, { &hf_sos_ah, { "Successive approximation bit position high", IMG_JFIF ".sos.ah", FT_UINT8, BASE_DEC, NULL, 0xF0, "This parameter specifies the point transform used in the " "preceding scan (i.e. successive approximation bit position " "low in the preceding scan) for the band of coefficients " "specified by Ss and Se. This parameter shall be set to zero " "for the first scan of each band of coefficients. " "In the lossless mode of operations this parameter has no " "meaning. It shall be set to zero.", HFILL } }, { &hf_sos_al, { "Successive approximation bit position low or point transform", IMG_JFIF ".sos.al", FT_UINT8, BASE_DEC, NULL, 0x0F, "In the DCT modes of operation this parameter specifies the " "point transform, i.e. bit position low, used before coding " "the band of coefficients specified by Ss and Se. " "This parameter shall be set to zero for the sequential DCT " "processes. In the lossless mode of operations, this " "parameter specifies the point transform, Pt.", HFILL } }, }; /* Setup protocol subtree array */ static gint *ett[] = { &ett_jfif, &ett_marker_segment, &ett_details, }; /* Register the protocol name and description */ proto_jfif = proto_register_protocol( "JPEG File Interchange Format", "JFIF (JPEG) image", IMG_JFIF ); /* Required function calls to register the header fields * and subtrees used */ proto_register_field_array(proto_jfif, hf, array_length(hf)); proto_register_subtree_array(ett, array_length(ett)); register_dissector("image-jfif", dissect_jfif, proto_jfif); } void proto_reg_handoff_jfif(void) { dissector_handle_t jfif_handle; jfif_handle = create_dissector_handle(dissect_jfif, proto_jfif); /* Register the GIF media type */ dissector_add_string("media_type", "image/jfif", jfif_handle); dissector_add_string("media_type", "image/jpg", jfif_handle); dissector_add_string("media_type", "image/jpeg", jfif_handle); }