xref: /freebsd/crypto/openssl/doc/man3/OSSL_DISPATCH.pod (revision b077aed33b7b6aefca7b17ddb250cf521f938613)
1*b077aed3SPierre Pronchery=pod
2*b077aed3SPierre Pronchery
3*b077aed3SPierre Pronchery=head1 NAME
4*b077aed3SPierre Pronchery
5*b077aed3SPierre ProncheryOSSL_DISPATCH - OpenSSL Core type to define a dispatchable function table
6*b077aed3SPierre Pronchery
7*b077aed3SPierre Pronchery=head1 SYNOPSIS
8*b077aed3SPierre Pronchery
9*b077aed3SPierre Pronchery #include <openssl/core.h>
10*b077aed3SPierre Pronchery
11*b077aed3SPierre Pronchery typedef struct ossl_dispatch_st OSSL_DISPATCH;
12*b077aed3SPierre Pronchery struct ossl_dispatch_st {
13*b077aed3SPierre Pronchery     int function_id;
14*b077aed3SPierre Pronchery     void (*function)(void);
15*b077aed3SPierre Pronchery };
16*b077aed3SPierre Pronchery
17*b077aed3SPierre Pronchery=head1 DESCRIPTION
18*b077aed3SPierre Pronchery
19*b077aed3SPierre ProncheryThis type is a tuple of function identity and function pointer.
20*b077aed3SPierre ProncheryArrays of this type are passed between the OpenSSL libraries and the
21*b077aed3SPierre Proncheryproviders to describe what functionality one side provides to the other.
22*b077aed3SPierre Pronchery
23*b077aed3SPierre ProncheryArrays of this type must be terminated with a tuple having function identity
24*b077aed3SPierre Proncheryzero and function pointer NULL.
25*b077aed3SPierre Pronchery
26*b077aed3SPierre Pronchery=head2 B<OSSL_DISPATCH> fields
27*b077aed3SPierre Pronchery
28*b077aed3SPierre Pronchery=over 4
29*b077aed3SPierre Pronchery
30*b077aed3SPierre Pronchery=item I<function_id>
31*b077aed3SPierre Pronchery
32*b077aed3SPierre ProncheryOpenSSL defined function identity of the implemented function.
33*b077aed3SPierre Pronchery
34*b077aed3SPierre Pronchery=item I<function>
35*b077aed3SPierre Pronchery
36*b077aed3SPierre ProncheryPointer to the implemented function itself.  Despite the generic definition
37*b077aed3SPierre Proncheryof this field, the implemented function it points to must have a function
38*b077aed3SPierre Proncherysignature that corresponds to the I<function_id>
39*b077aed3SPierre Pronchery
40*b077aed3SPierre Pronchery=back
41*b077aed3SPierre Pronchery
42*b077aed3SPierre ProncheryAvailable function identities and corresponding function signatures are
43*b077aed3SPierre Proncherydefined in L<openssl-core_dispatch.h(7)>.
44*b077aed3SPierre ProncheryFurthermore, the chosen function identities and associated function
45*b077aed3SPierre Proncherysignature must be chosen specifically for the operation that it's intended
46*b077aed3SPierre Proncheryfor, as determined by the intended L<OSSL_ALGORITHM(3)> array.
47*b077aed3SPierre Pronchery
48*b077aed3SPierre ProncheryAny function identity not recognised by the recipient of this type
49*b077aed3SPierre Proncherywill be ignored.
50*b077aed3SPierre ProncheryThis ensures that providers built with one OpenSSL version in mind
51*b077aed3SPierre Proncherywill work together with any other OpenSSL version that supports this
52*b077aed3SPierre Proncherymechanism.
53*b077aed3SPierre Pronchery
54*b077aed3SPierre Pronchery=begin comment RETURN VALUES doesn't make sense for a manual that only
55*b077aed3SPierre Proncherydescribes a type, but document checkers still want that section, and
56*b077aed3SPierre Proncheryto have more than just the section title.
57*b077aed3SPierre Pronchery
58*b077aed3SPierre Pronchery=head1 RETURN VALUES
59*b077aed3SPierre Pronchery
60*b077aed3SPierre Proncherytxt
61*b077aed3SPierre Pronchery
62*b077aed3SPierre Pronchery=end comment
63*b077aed3SPierre Pronchery
64*b077aed3SPierre Pronchery=head1 SEE ALSO
65*b077aed3SPierre Pronchery
66*b077aed3SPierre ProncheryL<crypto(7)>, L<openssl-core_dispatch.h(7)>, L<OSSL_ALGORITHM(3)>
67*b077aed3SPierre Pronchery
68*b077aed3SPierre Pronchery=head1 HISTORY
69*b077aed3SPierre Pronchery
70*b077aed3SPierre ProncheryB<OSSL_DISPATCH> was added in OpenSSL 3.0.
71*b077aed3SPierre Pronchery
72*b077aed3SPierre Pronchery=head1 COPYRIGHT
73*b077aed3SPierre Pronchery
74*b077aed3SPierre ProncheryCopyright 2022 The OpenSSL Project Authors. All Rights Reserved.
75*b077aed3SPierre Pronchery
76*b077aed3SPierre ProncheryLicensed under the Apache License 2.0 (the "License").  You may not use
77*b077aed3SPierre Proncherythis file except in compliance with the License.  You can obtain a copy
78*b077aed3SPierre Proncheryin the file LICENSE in the source distribution or at
79*b077aed3SPierre ProncheryL<https://www.openssl.org/source/license.html>.
80*b077aed3SPierre Pronchery
81*b077aed3SPierre Pronchery=cut
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