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       int32_t kcapi_cipher_stream_update(struct kcapi_handle * handle,
10                                          struct iovec * iov,
11                                          uint32_t iovlen);
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ARGUMENTS

14       handle
15           [in] cipher handle
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17       iov
18           [in] scatter/gather list with data to be processed by the cipher
19           operation.
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21       iovlen
22           [in] number of scatter/gather list elements.
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DESCRIPTION

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

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

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

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

57       Stephan Mueller <smueller@chronox.de>
58           Author.
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61libkcapi Manual 1.2.0             August 2020          KCAPI_CIPHER_STREAM_(3)
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