gst/gstprotection.c - imx-gstreamer - Git at Google

 /* GStreamer
  * Copyright (C) <2013> YouView TV Ltd.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library 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
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public
  * License along with this library; if not, write to the
  * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */

 /**
  * SECTION:gstprotection
  * @title: GstProtection
  * @short_description: Functions and classes to support encrypted streams.
  *
  * The GstProtectionMeta class enables the information needed to decrypt a
  * #GstBuffer to be attached to that buffer.
  *
  * Typically, a demuxer element would attach GstProtectionMeta objects
  * to the buffers that it pushes downstream. The demuxer would parse the
  * protection information for a video/audio frame from its input data and use
  * this information to populate the #GstStructure @info field,
  * which is then encapsulated in a GstProtectionMeta object and attached to
  * the corresponding output buffer using the gst_buffer_add_protection_meta()
  * function. The information in this attached GstProtectionMeta would be
  * used by a downstream decrypter element to recover the original unencrypted
  * frame.
  *
  * Since: 1.6
  */

 #include "gst_private.h"
 #include "glib-compat-private.h"

 #include "gstprotection.h"

 #define GST_CAT_DEFAULT GST_CAT_PROTECTION

 static gboolean gst_protection_meta_init (GstMeta * meta, gpointer params,
     GstBuffer * buffer);

 static void gst_protection_meta_free (GstMeta * meta, GstBuffer * buffer);

 static const gchar *gst_protection_factory_check (GstElementFactory * fact,
     const gchar ** system_identifiers);

 GType
 gst_protection_meta_api_get_type (void)
 {
   static volatile GType type;
   static const gchar *tags[] = { NULL };

   if (g_once_init_enter (&type)) {
     GType _type = gst_meta_api_type_register ("GstProtectionMetaAPI", tags);
     g_once_init_leave (&type, _type);
   }
   return type;
 }

 static gboolean
 gst_protection_meta_init (GstMeta * meta, gpointer params, GstBuffer * buffer)
 {
   GstProtectionMeta *protection_meta = (GstProtectionMeta *) meta;

   protection_meta->info = NULL;

   return TRUE;
 }

 static void
 gst_protection_meta_free (GstMeta * meta, GstBuffer * buffer)
 {
   GstProtectionMeta *protection_meta = (GstProtectionMeta *) meta;

   if (protection_meta->info)
     gst_structure_free (protection_meta->info);
 }

 static gboolean
 gst_protection_meta_transform (GstBuffer * transbuf, GstMeta * meta,
     GstBuffer * buffer, GQuark type, gpointer data)
 {
   GstProtectionMeta *protection_meta = (GstProtectionMeta *) meta;

   if (GST_META_TRANSFORM_IS_COPY (type)) {
     GstMetaTransformCopy *copy = data;
     if (!copy->region) {
       /* only copy if the complete data is copied as well */
       gst_buffer_add_protection_meta (transbuf,
           gst_structure_copy (protection_meta->info));
     } else {
       return FALSE;
     }
   } else {
     /* transform type not supported */
     return FALSE;
   }
   return TRUE;
 }

 const GstMetaInfo *
 gst_protection_meta_get_info (void)
 {
   static const GstMetaInfo *protection_meta_info = NULL;

   if (g_once_init_enter ((GstMetaInfo **) & protection_meta_info)) {
     const GstMetaInfo *meta =
         gst_meta_register (GST_PROTECTION_META_API_TYPE, "GstProtectionMeta",
         sizeof (GstProtectionMeta), gst_protection_meta_init,
         gst_protection_meta_free, gst_protection_meta_transform);

     g_once_init_leave ((GstMetaInfo **) & protection_meta_info,
         (GstMetaInfo *) meta);
   }
   return protection_meta_info;
 }

 /**
  * gst_buffer_add_protection_meta:
  * @buffer: #GstBuffer holding an encrypted sample, to which protection
  *     metadata should be added.
  * @info: (transfer full): a #GstStructure holding cryptographic
  *     information relating to the sample contained in @buffer. This
  *     function takes ownership of @info.
  *
  * Attaches protection metadata to a #GstBuffer.
  *
  * Returns: (transfer none): a pointer to the added #GstProtectionMeta if successful; %NULL if
  * unsuccessful.
  *
  * Since: 1.6
  */
 GstProtectionMeta *
 gst_buffer_add_protection_meta (GstBuffer * buffer, GstStructure * info)
 {
   GstProtectionMeta *meta;

   g_return_val_if_fail (GST_IS_BUFFER (buffer), NULL);
   g_return_val_if_fail (info != NULL, NULL);

   meta =
       (GstProtectionMeta *) gst_buffer_add_meta (buffer,
       GST_PROTECTION_META_INFO, NULL);

   meta->info = info;

   return meta;
 }

 /**
  * gst_protection_select_system:
  * @system_identifiers: (transfer none) (array zero-terminated=1): A null terminated array of strings
  * that contains the UUID values of each protection system that is to be
  * checked.
  *
  * Iterates the supplied list of UUIDs and checks the GstRegistry for
  * an element that supports one of the supplied UUIDs. If more than one
  * element matches, the system ID of the highest ranked element is selected.
  *
  * Returns: (transfer none) (nullable): One of the strings from
  * @system_identifiers that indicates the highest ranked element that
  * implements the protection system indicated by that system ID, or %NULL if no
  * element has been found.
  *
  * Since: 1.6
  */
 const gchar *
 gst_protection_select_system (const gchar ** system_identifiers)
 {
   GList *decryptors, *walk;
   const gchar *retval = NULL;

   decryptors =
       gst_element_factory_list_get_elements (GST_ELEMENT_FACTORY_TYPE_DECRYPTOR,
       GST_RANK_MARGINAL);

   for (walk = decryptors; !retval && walk; walk = g_list_next (walk)) {
     GstElementFactory *fact = (GstElementFactory *) walk->data;

     retval = gst_protection_factory_check (fact, system_identifiers);
   }

   gst_plugin_feature_list_free (decryptors);

   return retval;
 }

 /**
  * gst_protection_filter_systems_by_available_decryptors:
  * @system_identifiers: (transfer none): A null terminated array of strings
  * that contains the UUID values of each protection system that is to be
  * checked.
  *
  * Iterates the supplied list of UUIDs and checks the GstRegistry for
  * all the decryptors supporting one of the supplied UUIDs.
  *
  * Returns: (transfer full) (nullable): A null terminated array containing all
  * the @system_identifiers supported by the set of available decryptors, or
  * %NULL if no matches were found.
  *
  * Since: 1.14
  */
 gchar **
 gst_protection_filter_systems_by_available_decryptors (const gchar **
     system_identifiers)
 {
   GList *decryptors, *walk;
   gchar **retval;
   guint i = 0, decryptors_number;

   decryptors =
       gst_element_factory_list_get_elements (GST_ELEMENT_FACTORY_TYPE_DECRYPTOR,
       GST_RANK_MARGINAL);

   decryptors_number = g_list_length (decryptors);

   GST_TRACE ("found %u decrytors", decryptors_number);

   if (decryptors_number == 0)
     return NULL;

   retval = g_new (gchar *, decryptors_number + 1);

   for (walk = decryptors; walk; walk = g_list_next (walk)) {
     GstElementFactory *fact = (GstElementFactory *) walk->data;
     const char *found_sys_id =
         gst_protection_factory_check (fact, system_identifiers);

     GST_DEBUG ("factory %s is valid for %s", GST_OBJECT_NAME (fact),
         found_sys_id);

     if (found_sys_id) {
       retval[i++] = g_strdup (found_sys_id);
     }
   }
   retval[i] = NULL;

   if (retval[0] == NULL) {
     g_free (retval);
     retval = NULL;
   }

   gst_plugin_feature_list_free (decryptors);

   return retval;
 }

 static const gchar *
 gst_protection_factory_check (GstElementFactory * fact,
     const gchar ** system_identifiers)
 {
   const GList *template, *walk;
   const gchar *retval = NULL;

   template = gst_element_factory_get_static_pad_templates (fact);
   for (walk = template; walk && !retval; walk = g_list_next (walk)) {
     GstStaticPadTemplate *templ = walk->data;
     GstCaps *caps = gst_static_pad_template_get_caps (templ);
     guint leng = gst_caps_get_size (caps);
     guint i, j;

     for (i = 0; !retval && i < leng; ++i) {
       GstStructure *st;

       st = gst_caps_get_structure (caps, i);
       if (gst_structure_has_field_typed (st,
               GST_PROTECTION_SYSTEM_ID_CAPS_FIELD, G_TYPE_STRING)) {
         const gchar *sys_id =
             gst_structure_get_string (st, GST_PROTECTION_SYSTEM_ID_CAPS_FIELD);
         GST_DEBUG ("Found decryptor that supports protection system %s",
             sys_id);
         for (j = 0; !retval && system_identifiers[j]; ++j) {
           GST_TRACE ("  compare with %s", system_identifiers[j]);
           if (g_ascii_strcasecmp (system_identifiers[j], sys_id) == 0) {
             GST_DEBUG ("  Selecting %s", system_identifiers[j]);
             retval = system_identifiers[j];
           }
         }
       }
     }
     gst_caps_unref (caps);
   }

   return retval;
 }
	/* GStreamer
	* Copyright (C) <2013> YouView TV Ltd.
	*
	* This library is free software; you can redistribute it and/or
	* modify it under the terms of the GNU Library General Public
	* License as published by the Free Software Foundation; either
	* version 2 of the License, or (at your option) any later version.
	*
	* This library 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
	* Library General Public License for more details.
	*
	* You should have received a copy of the GNU Library General Public
	* License along with this library; if not, write to the
	* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
	* Boston, MA 02110-1301, USA.
	*/

	/**
	* SECTION:gstprotection
	* @title: GstProtection
	* @short_description: Functions and classes to support encrypted streams.
	*
	* The GstProtectionMeta class enables the information needed to decrypt a
	* #GstBuffer to be attached to that buffer.
	*
	* Typically, a demuxer element would attach GstProtectionMeta objects
	* to the buffers that it pushes downstream. The demuxer would parse the
	* protection information for a video/audio frame from its input data and use
	* this information to populate the #GstStructure @info field,
	* which is then encapsulated in a GstProtectionMeta object and attached to
	* the corresponding output buffer using the gst_buffer_add_protection_meta()
	* function. The information in this attached GstProtectionMeta would be
	* used by a downstream decrypter element to recover the original unencrypted
	* frame.
	*
	* Since: 1.6
	*/

	#include "gst_private.h"
	#include "glib-compat-private.h"

	#include "gstprotection.h"

	#define GST_CAT_DEFAULT GST_CAT_PROTECTION

	static gboolean gst_protection_meta_init (GstMeta * meta, gpointer params,
	GstBuffer * buffer);

	static void gst_protection_meta_free (GstMeta * meta, GstBuffer * buffer);

	static const gchar gst_protection_factory_check (GstElementFactory fact,
	const gchar ** system_identifiers);

	GType
	gst_protection_meta_api_get_type (void)
	{
	static volatile GType type;
	static const gchar *tags[] = { NULL };

	if (g_once_init_enter (&type)) {
	GType _type = gst_meta_api_type_register ("GstProtectionMetaAPI", tags);
	g_once_init_leave (&type, _type);
	}
	return type;
	}

	static gboolean
	gst_protection_meta_init (GstMeta * meta, gpointer params, GstBuffer * buffer)
	{
	GstProtectionMeta protection_meta = (GstProtectionMeta ) meta;

	protection_meta->info = NULL;

	return TRUE;
	}

	static void
	gst_protection_meta_free (GstMeta * meta, GstBuffer * buffer)
	{
	GstProtectionMeta protection_meta = (GstProtectionMeta ) meta;

	if (protection_meta->info)
	gst_structure_free (protection_meta->info);
	}

	static gboolean
	gst_protection_meta_transform (GstBuffer * transbuf, GstMeta * meta,
	GstBuffer * buffer, GQuark type, gpointer data)
	{
	GstProtectionMeta protection_meta = (GstProtectionMeta ) meta;

	if (GST_META_TRANSFORM_IS_COPY (type)) {
	GstMetaTransformCopy *copy = data;
	if (!copy->region) {
	/* only copy if the complete data is copied as well */
	gst_buffer_add_protection_meta (transbuf,
	gst_structure_copy (protection_meta->info));
	} else {
	return FALSE;
	}
	} else {
	/* transform type not supported */
	return FALSE;
	}
	return TRUE;
	}

	const GstMetaInfo *
	gst_protection_meta_get_info (void)
	{
	static const GstMetaInfo *protection_meta_info = NULL;

	if (g_once_init_enter ((GstMetaInfo **) & protection_meta_info)) {
	const GstMetaInfo *meta =
	gst_meta_register (GST_PROTECTION_META_API_TYPE, "GstProtectionMeta",
	sizeof (GstProtectionMeta), gst_protection_meta_init,
	gst_protection_meta_free, gst_protection_meta_transform);

	g_once_init_leave ((GstMetaInfo **) & protection_meta_info,
	(GstMetaInfo *) meta);
	}
	return protection_meta_info;
	}

	/**
	* gst_buffer_add_protection_meta:
	* @buffer: #GstBuffer holding an encrypted sample, to which protection
	* metadata should be added.
	* @info: (transfer full): a #GstStructure holding cryptographic
	* information relating to the sample contained in @buffer. This
	* function takes ownership of @info.
	*
	* Attaches protection metadata to a #GstBuffer.
	*
	* Returns: (transfer none): a pointer to the added #GstProtectionMeta if successful; %NULL if
	* unsuccessful.
	*
	* Since: 1.6
	*/
	GstProtectionMeta *
	gst_buffer_add_protection_meta (GstBuffer * buffer, GstStructure * info)
	{
	GstProtectionMeta *meta;

	g_return_val_if_fail (GST_IS_BUFFER (buffer), NULL);
	g_return_val_if_fail (info != NULL, NULL);

	meta =
	(GstProtectionMeta *) gst_buffer_add_meta (buffer,
	GST_PROTECTION_META_INFO, NULL);

	meta->info = info;

	return meta;
	}

	/**
	* gst_protection_select_system:
	* @system_identifiers: (transfer none) (array zero-terminated=1): A null terminated array of strings
	* that contains the UUID values of each protection system that is to be
	* checked.
	*
	* Iterates the supplied list of UUIDs and checks the GstRegistry for
	* an element that supports one of the supplied UUIDs. If more than one
	* element matches, the system ID of the highest ranked element is selected.
	*
	* Returns: (transfer none) (nullable): One of the strings from
	* @system_identifiers that indicates the highest ranked element that
	* implements the protection system indicated by that system ID, or %NULL if no
	* element has been found.
	*
	* Since: 1.6
	*/
	const gchar *
	gst_protection_select_system (const gchar ** system_identifiers)
	{
	GList decryptors, walk;
	const gchar *retval = NULL;

	decryptors =
	gst_element_factory_list_get_elements (GST_ELEMENT_FACTORY_TYPE_DECRYPTOR,
	GST_RANK_MARGINAL);

	for (walk = decryptors; !retval && walk; walk = g_list_next (walk)) {
	GstElementFactory fact = (GstElementFactory ) walk->data;

	retval = gst_protection_factory_check (fact, system_identifiers);
	}

	gst_plugin_feature_list_free (decryptors);

	return retval;
	}

	/**
	* gst_protection_filter_systems_by_available_decryptors:
	* @system_identifiers: (transfer none): A null terminated array of strings
	* that contains the UUID values of each protection system that is to be
	* checked.
	*
	* Iterates the supplied list of UUIDs and checks the GstRegistry for
	* all the decryptors supporting one of the supplied UUIDs.
	*
	* Returns: (transfer full) (nullable): A null terminated array containing all
	* the @system_identifiers supported by the set of available decryptors, or
	* %NULL if no matches were found.
	*
	* Since: 1.14
	*/
	gchar **
	gst_protection_filter_systems_by_available_decryptors (const gchar **
	system_identifiers)
	{
	GList decryptors, walk;
	gchar **retval;
	guint i = 0, decryptors_number;

	decryptors =
	gst_element_factory_list_get_elements (GST_ELEMENT_FACTORY_TYPE_DECRYPTOR,
	GST_RANK_MARGINAL);

	decryptors_number = g_list_length (decryptors);

	GST_TRACE ("found %u decrytors", decryptors_number);

	if (decryptors_number == 0)
	return NULL;

	retval = g_new (gchar *, decryptors_number + 1);

	for (walk = decryptors; walk; walk = g_list_next (walk)) {
	GstElementFactory fact = (GstElementFactory ) walk->data;
	const char *found_sys_id =
	gst_protection_factory_check (fact, system_identifiers);

	GST_DEBUG ("factory %s is valid for %s", GST_OBJECT_NAME (fact),
	found_sys_id);

	if (found_sys_id) {
	retval[i++] = g_strdup (found_sys_id);
	}
	}
	retval[i] = NULL;

	if (retval[0] == NULL) {
	g_free (retval);
	retval = NULL;
	}

	gst_plugin_feature_list_free (decryptors);

	return retval;
	}

	static const gchar *
	gst_protection_factory_check (GstElementFactory * fact,
	const gchar ** system_identifiers)
	{
	const GList template, walk;
	const gchar *retval = NULL;

	template = gst_element_factory_get_static_pad_templates (fact);
	for (walk = template; walk && !retval; walk = g_list_next (walk)) {
	GstStaticPadTemplate *templ = walk->data;
	GstCaps *caps = gst_static_pad_template_get_caps (templ);
	guint leng = gst_caps_get_size (caps);
	guint i, j;

	for (i = 0; !retval && i < leng; ++i) {
	GstStructure *st;

	st = gst_caps_get_structure (caps, i);
	if (gst_structure_has_field_typed (st,
	GST_PROTECTION_SYSTEM_ID_CAPS_FIELD, G_TYPE_STRING)) {
	const gchar *sys_id =
	gst_structure_get_string (st, GST_PROTECTION_SYSTEM_ID_CAPS_FIELD);
	GST_DEBUG ("Found decryptor that supports protection system %s",
	sys_id);
	for (j = 0; !retval && system_identifiers[j]; ++j) {
	GST_TRACE (" compare with %s", system_identifiers[j]);
	if (g_ascii_strcasecmp (system_identifiers[j], sys_id) == 0) {
	GST_DEBUG (" Selecting %s", system_identifiers[j]);
	retval = system_identifiers[j];
	}
	}
	}
	}
	gst_caps_unref (caps);
	}

	return retval;
	}