1OPENSSL-CORE.H(7ossl) OpenSSL OPENSSL-CORE.H(7ossl)
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6 openssl/core.h - OpenSSL Core types
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9 #include <openssl/core.h>
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12 The <openssl/core.h> header defines a number of public types that are
13 used to communicate between the OpenSSL libraries and implementation
14 providers. These types are designed to minimise the need for intimate
15 knowledge of internal structures between the OpenSSL libraries and the
16 providers.
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18 The types are:
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20 OSSL_DISPATCH
21 This type is a tuple of function identity and function pointer.
22 Arrays of this type are passed between the OpenSSL libraries and
23 the providers to describe what functionality one side provides to
24 the other. Arrays of this type must be terminated with a tuple
25 having function identity zero and function pointer NULL.
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27 The available function identities and corresponding function
28 signatures are defined in openssl-core_dispatch.h(7).
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30 Any function identity not recognised by the recipient of this type
31 will be ignored. This ensures that providers built with one
32 OpenSSL version in mind will work together with any other OpenSSL
33 version that supports this mechanism.
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35 OSSL_ITEM
36 This type is a tuple of integer and pointer. It's a generic type
37 used as a generic descriptor, its exact meaning being defined by
38 how it's used. Arrays of this type are passed between the OpenSSL
39 libraries and the providers, and must be terminated with a tuple
40 where the integer is zero and the pointer NULL.
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42 OSSL_ALGORITHM
43 This type is a tuple of an algorithm name (string), a property
44 definition (string) and a dispatch table (array of OSSL_DISPATCH).
45 Arrays of this type are passed on demand from the providers to the
46 OpenSSL libraries to describe what algorithms the providers provide
47 implementations of, and with what properties. Arrays of this type
48 must be terminated with a tuple having function identity zero and
49 function pointer NULL.
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51 The algorithm names and property definitions are defined by the
52 providers.
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54 The OpenSSL libraries use the first of the algorithm names as the
55 main or canonical name, on a per algorithm implementation basis.
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57 OSSL_PARAM
58 This type is a structure that allows passing arbitrary object data
59 between two parties that have no or very little shared knowledge
60 about their respective internal structures for that object. It's
61 normally passed in arrays, where the array is terminated with an
62 element where all fields are zero (for non-pointers) or NULL (for
63 pointers).
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65 These arrays can be used to set parameters for some object, to
66 request parameters, and to describe parameters.
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68 OSSL_PARAM is further described in OSSL_PARAM(3)
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70 OSSL_CALLBACK
71 This is a function type for a generic feedback callback function:
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73 typedef int (OSSL_CALLBACK)(const OSSL_PARAM params[], void *arg);
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75 A function that takes a pointer of this type should also take a
76 pointer to caller data. When calling this callback, the function
77 is expected to build an OSSL_PARAM array of data it wants or is
78 expected to pass back, and pass that as params, as well as the
79 caller data pointer it received, as arg.
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81 OSSL_PASSPHRASE_CALLBACK
82 This is a function type for a generic pass phrase callback
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85 typedef int (OSSL_PASSPHRASE_CALLBACK)(char *pass, size_t pass_size,
86 size_t *pass_len,
87 const OSSL_PARAM params[],
88 void *arg);
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90 This callback can be used to prompt the user for a passphrase.
91 When calling it, a buffer to store the pass phrase needs to be
92 given with pass, and its size with pass_size. The length of the
93 prompted pass phrase will be given back in *pass_len.
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95 Additional parameters can be passed with the OSSL_PARAM array
96 params.
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98 A function that takes a pointer of this type should also take a
99 pointer to caller data, which should be passed as arg to this
100 callback.
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103 openssl-core_dispatch.h(7)
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106 The types described here were added in OpenSSL 3.0.
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109 Copyright 2019-2021 The OpenSSL Project Authors. All Rights Reserved.
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111 Licensed under the Apache License 2.0 (the "License"). You may not use
112 this file except in compliance with the License. You can obtain a copy
113 in the file LICENSE in the source distribution or at
114 <https://www.openssl.org/source/license.html>.
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1183.0.5 2022-07-05 OPENSSL-CORE.H(7ossl)