wiretap: Add MP4 reader

Allows opening MP4 (ISO/IEC 14496-12) media files in Wireshark and
viewing their structure.

Change-Id: Ie20b8b89dc69bb52d6faa890e547d90317adecf6
Reviewed-on: https://code.wireshark.org/review/35804
Petri-Dish: Stig Bjørlykke <stig@bjorlykke.org>
Tested-by: Petri Dish Buildbot
Reviewed-by: Guy Harris <guy@alum.mit.edu>

epan/dissectors/file-mp4.c

@@ -812,6 +812,7 @@ proto_reg_handoff_mp4(void)
     dissector_handle_t mp4_handle = create_dissector_handle(dissect_mp4, proto_mp4);
     dissector_add_string("media_type", "video/mp4", mp4_handle);
     dissector_add_string("media_type", "audio/mp4", mp4_handle);
+    dissector_add_uint("wtap_encap", WTAP_ENCAP_MP4, mp4_handle);
 }
 
 

wiretap/CMakeLists.txt

@@ -53,6 +53,7 @@ set(WIRETAP_NONGENERATED_FILES
 	logcat.c
 	logcat_text.c
 	merge.c
+	mp4.c
 	mpeg.c
 	mplog.c
 	mime_file.c

wiretap/file_access.c

@@ -51,6 +51,7 @@
 #include "k12.h"
 #include "ber.h"
 #include "catapult_dct2000.h"
+#include "mp4.h"
 #include "mp2t.h"
 #include "mpeg.h"
 #include "netscreen.h"
@@ -152,6 +153,7 @@ static const struct file_extension_info file_type_extensions_base[] = {
 	{ "Transport-Neutral Encapsulation Format", FALSE, "tnef" },
 	{ "JPEG/JFIF files", FALSE, "jpg;jpeg;jfif" },
 	{ "JavaScript Object Notation file", FALSE, "json" },
+	{ "MP4 file", FALSE, "mp4" },
 };
 
 #define	N_FILE_TYPE_EXTENSIONS	(sizeof file_type_extensions_base / sizeof file_type_extensions_base[0])
@@ -430,6 +432,7 @@ static const struct open_info open_info_base[] = {
 	{ "Ruby Marshal Object",                    OPEN_INFO_HEURISTIC, ruby_marshal_open,        "",         NULL, NULL },
 	{ "Systemd Journal",                        OPEN_INFO_HEURISTIC, systemd_journal_open,     "log;jnl;journal",      NULL, NULL },
 	{ "3gpp phone log",                         OPEN_INFO_MAGIC,     log3gpp_open,             "log",      NULL, NULL },
+	{ "MP4 media file",                         OPEN_INFO_MAGIC,     mp4_open,                 "mp4",      NULL, NULL },
 
 };
 
@@ -1665,6 +1668,11 @@ static const struct file_type_subtype_info dump_open_table_base[] = {
 	/* WTAP_FILE_TYPE_SUBTYPE_LOG_3GPP */
 	{ "3GPP Log", "3gpp_log", "*.log", NULL,
 	  TRUE, FALSE, 0,
+	  NULL, NULL, NULL },
+
+	/* WTAP_FILE_TYPE_SUBTYPE_MP4 */
+	{ "MP4 media", "mp4", "mp4", NULL,
+	  FALSE, FALSE, 0,
 	  NULL, NULL, NULL }
 };
 

wiretap/mp4.c

@@ -0,0 +1,60 @@
+/* mp4.c
+ *
+ * MP4 (ISO/IEC 14496-12) file format decoder for the Wiretap library.
+ *
+ * Wiretap Library
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "mp4.h"
+
+#include "file_wrappers.h"
+#include "wtap-int.h"
+
+static const guint8 mp4_magic[] = { 'f', 't', 'y', 'p' };
+
+wtap_open_return_val
+mp4_open(wtap *wth, int *err, gchar **err_info)
+{
+	char magic_buf[8];
+	int bytes_read;
+
+	bytes_read = file_read(magic_buf, sizeof (magic_buf), wth->fh);
+
+	if (bytes_read < 0) {
+		*err = file_error(wth->fh, err_info);
+		return WTAP_OPEN_ERROR;
+	}
+	if (bytes_read == 0)
+		return WTAP_OPEN_NOT_MINE;
+
+	if (bytes_read == sizeof (magic_buf) &&
+			memcmp(magic_buf + 4, mp4_magic, sizeof (mp4_magic)))
+		return WTAP_OPEN_NOT_MINE;
+
+	if (file_seek(wth->fh, 0, SEEK_SET, err) == -1)
+		return WTAP_OPEN_ERROR;
+
+	wth->file_type_subtype = WTAP_FILE_TYPE_SUBTYPE_MP4;
+	wth->file_encap = WTAP_ENCAP_MP4;
+	wth->file_tsprec = WTAP_TSPREC_SEC;
+	wth->subtype_read = wtap_full_file_read;
+	wth->subtype_seek_read = wtap_full_file_seek_read;
+	wth->snapshot_length = 0;
+
+	return WTAP_OPEN_MINE;
+}
+
+/*
+ * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
+ *
+ * Local variables:
+ * c-basic-offset: 8
+ * tab-width: 8
+ * indent-tabs-mode: t
+ * End:
+ *
+ * vi: set shiftwidth=8 tabstop=8 noexpandtab:
+ * :indentSize=8:tabSize=8:noTabs=false:
+ */

wiretap/mp4.h

@@ -0,0 +1,16 @@
+/* mp4.h
+ *
+ * MP4 (ISO/IEC 14496-12) file format decoder for the Wiretap library.
+ *
+ * Wiretap Library
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef __W_MP4_H__
+#define __W_MP4_H__
+
+#include "wtap.h"
+
+wtap_open_return_val mp4_open(wtap *wth, int *err, gchar **err_info);
+
+#endif

wiretap/wtap.h

@@ -289,6 +289,7 @@ extern "C" {
 #define WTAP_ENCAP_IEEE802_15_4_TAP             206
 #define WTAP_ENCAP_LOG_3GPP                     207
 #define WTAP_ENCAP_USB_2_0                      208
+#define WTAP_ENCAP_MP4                          209
 
 /* After adding new item here, please also add new item to encap_table_base array */
 
@@ -385,6 +386,7 @@ extern "C" {
 #define WTAP_FILE_TYPE_SUBTYPE_RUBY_MARSHAL                  83
 #define WTAP_FILE_TYPE_SUBTYPE_SYSTEMD_JOURNAL               84
 #define WTAP_FILE_TYPE_SUBTYPE_LOG_3GPP                      85
+#define WTAP_FILE_TYPE_SUBTYPE_MP4                           86
 
 #define WTAP_NUM_FILE_TYPES_SUBTYPES  wtap_get_num_file_types_subtypes()