1KCAPI_CIPHER_STREAM_(3)      Programming Interface     KCAPI_CIPHER_STREAM_(3)
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NAME

6       kcapi_cipher_stream_op - obtain processed data (stream)
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SYNOPSIS

9       ssize_t kcapi_cipher_stream_op(struct kcapi_handle * handle,
10                                      struct iovec * iov, size_t iovlen);
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ARGUMENTS

13       handle
14           [in] cipher handle
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16       iov
17           [out] scatter/gather list pointing to buffers to be filled with the
18           resulting data from a cipher operation.
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20       iovlen
21           [in] number of scatter/gather list elements.
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DESCRIPTION

24       This call can be called interleaved with kcapi_cipher_stream_update to
25       fetch the processed data.
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27       This function may cause the caller to sleep if the kernel buffer
28       holding the data is empty. The process will be woken up once more data
29       is sent by calling kcapi_cipher_stream_update.
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31       Note, when supplying buffers that are not multiple of block size, the
32       buffers will only be filled up to the maximum number of full block
33       sizes that fit into the buffer.
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35       The kernel supports multithreaded applications where one or more
36       threads send data via the kcapi_cipher_stream_update function and
37       another thread collects the processed data via kcapi_cipher_stream_op.
38       The kernel, however, will return data via kcapi_cipher_stream_op as
39       soon as it has some data available. For example, one thread sends 1000
40       bytes to be encrypted and another thread already waits for the
41       ciphertext. The kernel may send only, say, 500 bytes back to the
42       waiting process during one kcapi_cipher_stream_op call. In a subsequent
43       calls to kcapi_cipher_stream_op more ciphertext is returned. This
44       implies that when the receiving thread shall collect all data there is,
45       kcapi_cipher_stream_op must be called in a loop until all data is
46       received.
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48       return number of bytes obtained from the kernel upon success; a
49       negative errno-style error code if an error occurred
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AUTHOR

52       Stephan Mueller <smueller@chronox.de>
53           Author.
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56libkcapi Manual 1.4.0            January 2023          KCAPI_CIPHER_STREAM_(3)
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