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crypto: doc - AHASH API documentation 

The API function calls exported by the kernel crypto API for AHASHes
to be used by consumers are documented.

Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Stephan Mueller 2014-11-12 05:26:41 +01:00 committed by Herbert Xu
parent 5d8c723f61
commit 90240ffb12
1 changed files with 228 additions and 0 deletions
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228
include/crypto/hash.h
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@ -202,11 +202,35 @@ struct crypto_shash {
struct crypto_tfm base;
};
/**
* DOC: Asynchronous Message Digest API
*
* The asynchronous message digest API is used with the ciphers of type
* CRYPTO_ALG_TYPE_AHASH (listed as type "ahash" in /proc/crypto)
*
* The asynchronous cipher operation discussion provided for the
* CRYPTO_ALG_TYPE_ABLKCIPHER API applies here as well.
*/
static inline struct crypto_ahash *__crypto_ahash_cast(struct crypto_tfm *tfm)
{
return container_of(tfm, struct crypto_ahash, base);
}
/**
* crypto_alloc_ahash() - allocate ahash cipher handle
* @alg_name: is the cra_name / name or cra_driver_name / driver name of the
* ahash cipher
* @type: specifies the type of the cipher
* @mask: specifies the mask for the cipher
*
* Allocate a cipher handle for an ahash. The returned struct
* crypto_ahash is the cipher handle that is required for any subsequent
* API invocation for that ahash.
*
* Return: allocated cipher handle in case of success; IS_ERR() is true in case
* of an error, PTR_ERR() returns the error code.
*/
struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type,
u32 mask);
@ -215,6 +239,10 @@ static inline struct crypto_tfm *crypto_ahash_tfm(struct crypto_ahash *tfm)
return &tfm->base;
}
/**
* crypto_free_ahash() - zeroize and free the ahash handle
* @tfm: cipher handle to be freed
*/
static inline void crypto_free_ahash(struct crypto_ahash *tfm)
{
crypto_destroy_tfm(tfm, crypto_ahash_tfm(tfm));
@ -238,6 +266,16 @@ static inline struct hash_alg_common *crypto_hash_alg_common(
return __crypto_hash_alg_common(crypto_ahash_tfm(tfm)->__crt_alg);
}
/**
* crypto_ahash_digestsize() - obtain message digest size
* @tfm: cipher handle
*
* The size for the message digest created by the message digest cipher
* referenced with the cipher handle is returned.
*
*
* Return: message digest size of cipher
*/
static inline unsigned int crypto_ahash_digestsize(struct crypto_ahash *tfm)
{
return crypto_hash_alg_common(tfm)->digestsize;
@ -263,12 +301,32 @@ static inline void crypto_ahash_clear_flags(struct crypto_ahash *tfm, u32 flags)
crypto_tfm_clear_flags(crypto_ahash_tfm(tfm), flags);
}
/**
* crypto_ahash_reqtfm() - obtain cipher handle from request
* @req: asynchronous request handle that contains the reference to the ahash
* cipher handle
*
* Return the ahash cipher handle that is registered with the asynchronous
* request handle ahash_request.
*
* Return: ahash cipher handle
*/
static inline struct crypto_ahash *crypto_ahash_reqtfm(
struct ahash_request *req)
{
return __crypto_ahash_cast(req->base.tfm);
}
/**
* crypto_ahash_reqsize() - obtain size of the request data structure
* @tfm: cipher handle
*
* Return the size of the ahash state size. With the crypto_ahash_export
* function, the caller can export the state into a buffer whose size is
* defined with this function.
*
* Return: size of the ahash state
*/
static inline unsigned int crypto_ahash_reqsize(struct crypto_ahash *tfm)
{
return tfm->reqsize;
@ -279,38 +337,166 @@ static inline void *ahash_request_ctx(struct ahash_request *req)
return req->__ctx;
}
/**
* crypto_ahash_setkey - set key for cipher handle
* @tfm: cipher handle
* @key: buffer holding the key
* @keylen: length of the key in bytes
*
* The caller provided key is set for the ahash cipher. The cipher
* handle must point to a keyed hash in order for this function to succeed.
*
* Return: 0 if the setting of the key was successful; < 0 if an error occurred
*/
int crypto_ahash_setkey(struct crypto_ahash *tfm, const u8 *key,
unsigned int keylen);
/**
* crypto_ahash_finup() - update and finalize message digest
* @req: reference to the ahash_request handle that holds all information
* needed to perform the cipher operation
*
* This function is a "short-hand" for the function calls of
* crypto_ahash_update and crypto_shash_final. The parameters have the same
* meaning as discussed for those separate functions.
*
* Return: 0 if the message digest creation was successful; < 0 if an error
* occurred
*/
int crypto_ahash_finup(struct ahash_request *req);
/**
* crypto_ahash_final() - calculate message digest
* @req: reference to the ahash_request handle that holds all information
* needed to perform the cipher operation
*
* Finalize the message digest operation and create the message digest
* based on all data added to the cipher handle. The message digest is placed
* into the output buffer registered with the ahash_request handle.
*
* Return: 0 if the message digest creation was successful; < 0 if an error
* occurred
*/
int crypto_ahash_final(struct ahash_request *req);
/**
* crypto_ahash_digest() - calculate message digest for a buffer
* @req: reference to the ahash_request handle that holds all information
* needed to perform the cipher operation
*
* This function is a "short-hand" for the function calls of crypto_ahash_init,
* crypto_ahash_update and crypto_ahash_final. The parameters have the same
* meaning as discussed for those separate three functions.
*
* Return: 0 if the message digest creation was successful; < 0 if an error
* occurred
*/
int crypto_ahash_digest(struct ahash_request *req);
/**
* crypto_ahash_export() - extract current message digest state
* @req: reference to the ahash_request handle whose state is exported
* @out: output buffer of sufficient size that can hold the hash state
*
* This function exports the hash state of the ahash_request handle into the
* caller-allocated output buffer out which must have sufficient size (e.g. by
* calling crypto_ahash_reqsize).
*
* Return: 0 if the export was successful; < 0 if an error occurred
*/
static inline int crypto_ahash_export(struct ahash_request *req, void *out)
{
return crypto_ahash_reqtfm(req)->export(req, out);
}
/**
* crypto_ahash_import() - import message digest state
* @req: reference to ahash_request handle the state is imported into
* @in: buffer holding the state
*
* This function imports the hash state into the ahash_request handle from the
* input buffer. That buffer should have been generated with the
* crypto_ahash_export function.
*
* Return: 0 if the import was successful; < 0 if an error occurred
*/
static inline int crypto_ahash_import(struct ahash_request *req, const void *in)
{
return crypto_ahash_reqtfm(req)->import(req, in);
}
/**
* crypto_ahash_init() - (re)initialize message digest handle
* @req: ahash_request handle that already is initialized with all necessary
* data using the ahash_request_* API functions
*
* The call (re-)initializes the message digest referenced by the ahash_request
* handle. Any potentially existing state created by previous operations is
* discarded.
*
* Return: 0 if the message digest initialization was successful; < 0 if an
* error occurred
*/
static inline int crypto_ahash_init(struct ahash_request *req)
{
return crypto_ahash_reqtfm(req)->init(req);
}
/**
* crypto_ahash_update() - add data to message digest for processing
* @req: ahash_request handle that was previously initialized with the
* crypto_ahash_init call.
*
* Updates the message digest state of the &ahash_request handle. The input data
* is pointed to by the scatter/gather list registered in the &ahash_request
* handle
*
* Return: 0 if the message digest update was successful; < 0 if an error
* occurred
*/
static inline int crypto_ahash_update(struct ahash_request *req)
{
return crypto_ahash_reqtfm(req)->update(req);
}
/**
* DOC: Asynchronous Hash Request Handle
*
* The &ahash_request data structure contains all pointers to data
* required for the asynchronous cipher operation. This includes the cipher
* handle (which can be used by multiple &ahash_request instances), pointer
* to plaintext and the message digest output buffer, asynchronous callback
* function, etc. It acts as a handle to the ahash_request_* API calls in a
* similar way as ahash handle to the crypto_ahash_* API calls.
*/
/**
* ahash_request_set_tfm() - update cipher handle reference in request
* @req: request handle to be modified
* @tfm: cipher handle that shall be added to the request handle
*
* Allow the caller to replace the existing ahash handle in the request
* data structure with a different one.
*/
static inline void ahash_request_set_tfm(struct ahash_request *req,
struct crypto_ahash *tfm)
{
req->base.tfm = crypto_ahash_tfm(tfm);
}
/**
* ahash_request_alloc() - allocate request data structure
* @tfm: cipher handle to be registered with the request
* @gfp: memory allocation flag that is handed to kmalloc by the API call.
*
* Allocate the request data structure that must be used with the ahash
* message digest API calls. During
* the allocation, the provided ahash handle
* is registered in the request data structure.
*
* Return: allocated request handle in case of success; IS_ERR() is true in case
* of an error, PTR_ERR() returns the error code.
*/
static inline struct ahash_request *ahash_request_alloc(
struct crypto_ahash *tfm, gfp_t gfp)
{
@ -325,6 +511,10 @@ static inline struct ahash_request *ahash_request_alloc(
return req;
}
/**
* ahash_request_free() - zeroize and free the request data structure
* @req: request data structure cipher handle to be freed
*/
static inline void ahash_request_free(struct ahash_request *req)
{
kzfree(req);
@ -336,6 +526,31 @@ static inline struct ahash_request *ahash_request_cast(
return container_of(req, struct ahash_request, base);
}
/**
* ahash_request_set_callback() - set asynchronous callback function
* @req: request handle
* @flags: specify zero or an ORing of the flags
* CRYPTO_TFM_REQ_MAY_BACKLOG the request queue may back log and
* increase the wait queue beyond the initial maximum size;
* CRYPTO_TFM_REQ_MAY_SLEEP the request processing may sleep
* @compl: callback function pointer to be registered with the request handle
* @data: The data pointer refers to memory that is not used by the kernel
* crypto API, but provided to the callback function for it to use. Here,
* the caller can provide a reference to memory the callback function can
* operate on. As the callback function is invoked asynchronously to the
* related functionality, it may need to access data structures of the
* related functionality which can be referenced using this pointer. The
* callback function can access the memory via the "data" field in the
* &crypto_async_request data structure provided to the callback function.
*
* This function allows setting the callback function that is triggered once
* the cipher operation completes.
*
* The callback function is registered with the &ahash_request handle and
* must comply with the following template
*
* void callback_function(struct crypto_async_request *req, int error)
*/
static inline void ahash_request_set_callback(struct ahash_request *req,
u32 flags,
crypto_completion_t compl,
@ -346,6 +561,19 @@ static inline void ahash_request_set_callback(struct ahash_request *req,
req->base.flags = flags;
}
/**
* ahash_request_set_crypt() - set data buffers
* @req: ahash_request handle to be updated
* @src: source scatter/gather list
* @result: buffer that is filled with the message digest -- the caller must
* ensure that the buffer has sufficient space by, for example, calling
* crypto_ahash_digestsize()
* @nbytes: number of bytes to process from the source scatter/gather list
*
* By using this call, the caller references the source scatter/gather list.
* The source scatter/gather list points to the data the message digest is to
* be calculated for.
*/
static inline void ahash_request_set_crypt(struct ahash_request *req,
struct scatterlist *src, u8 *result,
unsigned int nbytes)