crypto: doc - hash data structures (5d8c723f) · Commits · git / linux-net

include/crypto/hash.h

+95 −0

Original line number	Diff line number	Diff line
		@@ -17,6 +17,28 @@

		struct crypto_ahash;

		/**
		* DOC: Message Digest Algorithm Definitions
		*
		* These data structures define modular message digest algorithm
		* implementations, managed via crypto_register_ahash(),
		* crypto_register_shash(), crypto_unregister_ahash() and
		* crypto_unregister_shash().
		*/

		/**
		* struct hash_alg_common - define properties of message digest
		* @digestsize: Size of the result of the transformation. A buffer of this size
		* must be available to the @final and @finup calls, so they can
		* store the resulting hash into it. For various predefined sizes,
		* search include/crypto/ using
		* git grep _DIGEST_SIZE include/crypto.
		* @statesize: Size of the block for partial state of the transformation. A
		* buffer of this size must be passed to the @export function as it
		* will save the partial state of the transformation into it. On the
		* other side, the @import function will load the state from a
		* buffer of this size as well.
		*/
		struct hash_alg_common {
		unsigned int digestsize;
		unsigned int statesize;
		@@ -37,6 +59,62 @@ struct ahash_request {
		void *__ctx[] CRYPTO_MINALIGN_ATTR;
		};

		/**
		* struct ahash_alg - asynchronous message digest definition
		* @init: Initialize the transformation context. Intended only to initialize the
		* state of the HASH transformation at the begining. This shall fill in
		* the internal structures used during the entire duration of the whole
		* transformation. No data processing happens at this point.
		* @update: Push a chunk of data into the driver for transformation. This
		* function actually pushes blocks of data from upper layers into the
		* driver, which then passes those to the hardware as seen fit. This
		* function must not finalize the HASH transformation by calculating the
		* final message digest as this only adds more data into the
		* transformation. This function shall not modify the transformation
		* context, as this function may be called in parallel with the same
		* transformation object. Data processing can happen synchronously
		* [SHASH] or asynchronously [AHASH] at this point.
		* @final: Retrieve result from the driver. This function finalizes the
		* transformation and retrieves the resulting hash from the driver and
		* pushes it back to upper layers. No data processing happens at this
		* point.
		* @finup: Combination of @update and @final. This function is effectively a
		* combination of @update and @final calls issued in sequence. As some
		* hardware cannot do @update and @final separately, this callback was
		* added to allow such hardware to be used at least by IPsec. Data
		* processing can happen synchronously [SHASH] or asynchronously [AHASH]
		* at this point.
		* @digest: Combination of @init and @update and @final. This function
		* effectively behaves as the entire chain of operations, @init,
		* @update and @final issued in sequence. Just like @finup, this was
		* added for hardware which cannot do even the @finup, but can only do
		* the whole transformation in one run. Data processing can happen
		* synchronously [SHASH] or asynchronously [AHASH] at this point.
		* @setkey: Set optional key used by the hashing algorithm. Intended to push
		* optional key used by the hashing algorithm from upper layers into
		* the driver. This function can store the key in the transformation
		* context or can outright program it into the hardware. In the former
		* case, one must be careful to program the key into the hardware at
		* appropriate time and one must be careful that .setkey() can be
		* called multiple times during the existence of the transformation
		* object. Not all hashing algorithms do implement this function as it
		* is only needed for keyed message digests. SHAx/MDx/CRCx do NOT
		* implement this function. HMAC(MDx)/HMAC(SHAx)/CMAC(AES) do implement
		* this function. This function must be called before any other of the
		* @init, @update, @final, @finup, @digest is called. No data
		* processing happens at this point.
		* @export: Export partial state of the transformation. This function dumps the
		* entire state of the ongoing transformation into a provided block of
		* data so it can be @import 'ed back later on. This is useful in case
		* you want to save partial result of the transformation after
		* processing certain amount of data and reload this partial result
		* multiple times later on for multiple re-use. No data processing
		* happens at this point.
		* @import: Import partial state of the transformation. This function loads the
		* entire state of the ongoing transformation from a provided block of
		* data so the transformation can continue from this point onward. No
		* data processing happens at this point.
		*/
		struct ahash_alg {
		int (init)(struct ahash_request req);
		int (update)(struct ahash_request req);
		@@ -63,6 +141,23 @@ struct shash_desc {
		crypto_shash_descsize(ctx)] CRYPTO_MINALIGN_ATTR; \
		struct shash_desc shash = (struct shash_desc )__##shash##_desc

		/**
		* struct shash_alg - synchronous message digest definition
		* @init: see struct ahash_alg
		* @update: see struct ahash_alg
		* @final: see struct ahash_alg
		* @finup: see struct ahash_alg
		* @digest: see struct ahash_alg
		* @export: see struct ahash_alg
		* @import: see struct ahash_alg
		* @setkey: see struct ahash_alg
		* @digestsize: see struct ahash_alg
		* @statesize: see struct ahash_alg
		* @dedcsize: Size of the operational state for the message digest. This state
		* size is the memory size that needs to be allocated for
		* shash_desc.__ctx
		* @base: internally used
		*/
		struct shash_alg {
		int (init)(struct shash_desc desc);
		int (update)(struct shash_desc desc, const u8 *data,