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

6       kcapi_cipher_stream_update - send more data for processing (stream)
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SYNOPSIS

9       ssize_t kcapi_cipher_stream_update(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           [in] scatter/gather list with data to be processed by the cipher
18           operation.
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20       iovlen
21           [in] number of scatter/gather list elements.
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DESCRIPTION

24       Using this function call, more plaintext for encryption or ciphertext
25       for decryption can be submitted to the kernel.
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27       This function may cause the caller to sleep if the kernel buffer
28       holding the data is getting full. The process will be woken up once
29       more buffer space becomes available by calling kcapi_cipher_stream_op.
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NOTE

32       with the separate API calls of kcapi_cipher_stream_update and
33       kcapi_cipher_stream_op a multi-threaded application can be implemented
34       where one thread sends data to be processed and one thread picks up
35       data processed by the cipher operation.
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IMPORTANT NOTE

38       The kernel will only process sysconf(_SC_PAGESIZE) * ALG_MAX_PAGES at
39       one time. If your input data is larger than this threshold, you MUST
40       segment it into chunks of at most sysconf(_SC_PAGESIZE) * ALG_MAX_PAGES
41       and invoke the kcapi_cipher_stream_update on that segment followed by
42       kcapi_cipher_stream_op before the next chunk is processed. If this rule
43       is not obeyed, the thread invoking kcapi_cipher_stream_update will be
44       put to sleep until another thread invokes kcapi_cipher_stream_op.
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WARNING

47       The memory referenced by iov is not accessed by the kernel during this
48       call. The memory is first accessed when kcapi_cipher_stream_op is
49       called. Thus, you MUST make sure that the referenced memory is still
50       present at the time kcapi_cipher_stream_op is called.
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52       return number of bytes sent to the kernel upon success; a negative
53       errno-style error code if an error occurred
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AUTHOR

56       Stephan Mueller <smueller@chronox.de>
57           Author.
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60libkcapi Manual 1.3.1              July 2021           KCAPI_CIPHER_STREAM_(3)
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