crypto: doc - hash data structures

The hash data structures needed to be filled in by cipher developers are documented. Signed-off-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: doc - hash data structures
The hash data structures needed to be filled in by cipher developers are documented. Signed-off-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Stephan Mueller · Herbert Xu
1 parent aa1b6fbcbe
Showing 1 changed file with 95 additions and 0 deletions Side-by-side Diff
include/crypto/hash.h
@@ -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 @@
 	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 @@
 		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,
...	...	@@ -17,6 +17,28 @@
17	17
18	18	struct crypto_ahash;
19	19
	20	+/**
	21	+ * DOC: Message Digest Algorithm Definitions
	22	+ *
	23	+ * These data structures define modular message digest algorithm
	24	+ * implementations, managed via crypto_register_ahash(),
	25	+ * crypto_register_shash(), crypto_unregister_ahash() and
	26	+ * crypto_unregister_shash().
	27	+ */
	28	+
	29	+/**
	30	+ * struct hash_alg_common - define properties of message digest
	31	+ * @digestsize: Size of the result of the transformation. A buffer of this size
	32	+ * must be available to the @final and @finup calls, so they can
	33	+ * store the resulting hash into it. For various predefined sizes,
	34	+ * search include/crypto/ using
	35	+ * git grep _DIGEST_SIZE include/crypto.
	36	+ * @statesize: Size of the block for partial state of the transformation. A
	37	+ * buffer of this size must be passed to the @export function as it
	38	+ * will save the partial state of the transformation into it. On the
	39	+ * other side, the @import function will load the state from a
	40	+ * buffer of this size as well.
	41	+ */
20	42	struct hash_alg_common {
21	43	unsigned int digestsize;
22	44	unsigned int statesize;
...	...	@@ -37,6 +59,62 @@
37	59	void *__ctx[] CRYPTO_MINALIGN_ATTR;
38	60	};
39	61
	62	+/**
	63	+ * struct ahash_alg - asynchronous message digest definition
	64	+ * @init: Initialize the transformation context. Intended only to initialize the
	65	+ * state of the HASH transformation at the begining. This shall fill in
	66	+ * the internal structures used during the entire duration of the whole
	67	+ * transformation. No data processing happens at this point.
	68	+ * @update: Push a chunk of data into the driver for transformation. This
	69	+ * function actually pushes blocks of data from upper layers into the
	70	+ * driver, which then passes those to the hardware as seen fit. This
	71	+ * function must not finalize the HASH transformation by calculating the
	72	+ * final message digest as this only adds more data into the
	73	+ * transformation. This function shall not modify the transformation
	74	+ * context, as this function may be called in parallel with the same
	75	+ * transformation object. Data processing can happen synchronously
	76	+ * [SHASH] or asynchronously [AHASH] at this point.
	77	+ * @final: Retrieve result from the driver. This function finalizes the
	78	+ * transformation and retrieves the resulting hash from the driver and
	79	+ * pushes it back to upper layers. No data processing happens at this
	80	+ * point.
	81	+ * @finup: Combination of @update and @final. This function is effectively a
	82	+ * combination of @update and @final calls issued in sequence. As some
	83	+ * hardware cannot do @update and @final separately, this callback was
	84	+ * added to allow such hardware to be used at least by IPsec. Data
	85	+ * processing can happen synchronously [SHASH] or asynchronously [AHASH]
	86	+ * at this point.
	87	+ * @digest: Combination of @init and @update and @final. This function
	88	+ * effectively behaves as the entire chain of operations, @init,
	89	+ * @update and @final issued in sequence. Just like @finup, this was
	90	+ * added for hardware which cannot do even the @finup, but can only do
	91	+ * the whole transformation in one run. Data processing can happen
	92	+ * synchronously [SHASH] or asynchronously [AHASH] at this point.
	93	+ * @setkey: Set optional key used by the hashing algorithm. Intended to push
	94	+ * optional key used by the hashing algorithm from upper layers into
	95	+ * the driver. This function can store the key in the transformation
	96	+ * context or can outright program it into the hardware. In the former
	97	+ * case, one must be careful to program the key into the hardware at
	98	+ * appropriate time and one must be careful that .setkey() can be
	99	+ * called multiple times during the existence of the transformation
	100	+ * object. Not all hashing algorithms do implement this function as it
	101	+ * is only needed for keyed message digests. SHAx/MDx/CRCx do NOT
	102	+ * implement this function. HMAC(MDx)/HMAC(SHAx)/CMAC(AES) do implement
	103	+ * this function. This function must be called before any other of the
	104	+ * @init, @update, @final, @finup, @digest is called. No data
	105	+ * processing happens at this point.
	106	+ * @export: Export partial state of the transformation. This function dumps the
	107	+ * entire state of the ongoing transformation into a provided block of
	108	+ * data so it can be @import 'ed back later on. This is useful in case
	109	+ * you want to save partial result of the transformation after
	110	+ * processing certain amount of data and reload this partial result
	111	+ * multiple times later on for multiple re-use. No data processing
	112	+ * happens at this point.
	113	+ * @import: Import partial state of the transformation. This function loads the
	114	+ * entire state of the ongoing transformation from a provided block of
	115	+ * data so the transformation can continue from this point onward. No
	116	+ * data processing happens at this point.
	117	+ */
40	118	struct ahash_alg {
41	119	int (init)(struct ahash_request req);
42	120	int (update)(struct ahash_request req);
...	...	@@ -63,6 +141,23 @@
63	141	crypto_shash_descsize(ctx)] CRYPTO_MINALIGN_ATTR; \
64	142	struct shash_desc shash = (struct shash_desc )__##shash##_desc
65	143
	144	+/**
	145	+ * struct shash_alg - synchronous message digest definition
	146	+ * @init: see struct ahash_alg
	147	+ * @update: see struct ahash_alg
	148	+ * @final: see struct ahash_alg
	149	+ * @finup: see struct ahash_alg
	150	+ * @digest: see struct ahash_alg
	151	+ * @export: see struct ahash_alg
	152	+ * @import: see struct ahash_alg
	153	+ * @setkey: see struct ahash_alg
	154	+ * @digestsize: see struct ahash_alg
	155	+ * @statesize: see struct ahash_alg
	156	+ * @dedcsize: Size of the operational state for the message digest. This state
	157	+ * size is the memory size that needs to be allocated for
	158	+ * shash_desc.__ctx
	159	+ * @base: internally used
	160	+ */
66	161	struct shash_alg {
67	162	int (init)(struct shash_desc desc);
68	163	int (update)(struct shash_desc desc, const u8 *data,