metadata: Add metadata factory and implementation for integer types

Co-authored-by: Thomas Egerer <[email protected]>

src/libstrongswan/metadata/metadata.h

@@ -0,0 +1,105 @@
+/*
+ * Copyright (C) 2021 Tobias Brunner, codelabs GmbH
+ * Copyright (C) 2021 Thomas Egerer, secunet AG
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+/**
+ * @defgroup metadata metadata
+ * @ingroup libstrongswan
+ *
+ * @defgroup metadata_t metadata
+ * @{ @ingroup metadata
+ */
+
+#ifndef METADATA_H_
+#define METADATA_H_
+
+#include <utils/utils.h>
+
+typedef struct metadata_t metadata_t;
+
+/**
+ * Pre-defined metadata type for int values. Note that while the constructor and
+ * equals() work with integer values/types smaller than int (such values get
+ * promoted to int when passed via ...), get() does not and expects a pointer to
+ * an int variable.
+ */
+#define METADATA_TYPE_INT "int"
+
+/**
+ * Pre-defined metadata type for uint64_t values. Make sure to pass only
+ * uint64_t values/variables also to the constructor and equals() (or cast them
+ * appropriately there).
+ */
+#define METADATA_TYPE_UINT64 "uint64"
+
+/**
+ * Metadata object to allow storing arbitrary values in an encapsulated
+ * object.
+ */
+struct metadata_t {
+
+	/**
+	 * Return the type of the metadata object.
+	 *
+	 * @return		string type of the metadata object
+	 */
+	const char *(*get_type)(metadata_t *this);
+
+	/**
+	 * Clone this metadata object.
+	 *
+	 * @return		a cloned instance
+	 */
+	metadata_t *(*clone)(metadata_t *this);
+
+	/**
+	 * Compare this to another value (or values, depending on the type).
+	 *
+	 * @param ...	value(s) (raw, not metadata_t) to compare this to
+	 * @return		TRUE if value is equal to metadata value
+	 */
+	bool (*equals)(metadata_t *this, ...);
+
+	/**
+	 * Retrieve the values via variadic argument(s).
+	 *
+	 * @param ...	pointer(s) to obtain metadata value(s)
+	 */
+	void (*get)(metadata_t *this, ...);
+
+	/**
+	 * Destroy this metadata object.
+	 */
+	void (*destroy)(metadata_t *this);
+};
+
+/**
+ * Constructor type for metadata objects.
+ *
+ * @param type		type of the metadata object, allows using the same
+ *					constructor for different types
+ * @param args		type-specific arguments
+ * @return			metadata object, NULL on failure
+ */
+typedef metadata_t *(*metadata_create_t)(const char *type, va_list args);
+
+#endif /** METADATA_H_ @}*/