kcapi_aead_stream_update — send more data for processing (stream)


int32_t kcapi_aead_stream_update (struct kcapi_handle * handle,
 struct iovec * iov,
 uint32_t iovlen);



[in] cipher handle


[in] scatter/gather list with data to be processed by the cipher operation.


[in] number of scatter/gather list elements.


Using this function call, more plaintext for encryption or ciphertext for decryption can be submitted to the kernel.

Note, see the order of input data as outlined in kcapi_aead_stream_init_dec.

This function may cause the caller to sleep if the kernel buffer holding the data is getting full. The process will be woken up once more buffer space becomes available by calling kcapi_aead_stream_op.


The last block of input data MUST be provided with kcapi_aead_stream_update_last as the kernel must be informed about the completion of the input data.

With the separate API calls of kcapi_aead_stream_update and kcapi_aead_stream_op a multi-threaded application can be implemented where one thread sends data to be processed and one thread picks up data processed by the cipher operation.


The kernel will only process sysconf(_SC_PAGESIZE) * ALG_MAX_PAGES at one time. Longer input data cannot be handled by the kernel.


The memory referenced by iov is not accessed by the kernel during this call. The memory is first accessed when kcapi_cipher_stream_op is called. Thus, you MUST make sure that the referenced memory is still present at the time kcapi_cipher_stream_op is called.

return number of bytes sent to the kernel upon success; a negative errno-style error code if an error occurred