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    Subject[PATCH v3 05/13] crypto: Documentation - hash data structures
    Date
    The hash data structures needed to be filled in by cipher developers are
    documented.

    Signed-off-by: Stephan Mueller <smueller@chronox.de>
    ---
    include/crypto/hash.h | 95 +++++++++++++++++++++++++++++++++++++++++++++++++++
    1 file changed, 95 insertions(+)

    diff --git a/include/crypto/hash.h b/include/crypto/hash.h
    index 74b13ec..bf458fc 100644
    --- a/include/crypto/hash.h
    +++ b/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 @@ 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,
    --
    2.1.0



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