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=head1 NAME

OSSL_CMP_ITAV_create,
OSSL_CMP_ITAV_set0,
OSSL_CMP_ITAV_get0_type,
OSSL_CMP_ITAV_get0_value,
OSSL_CMP_ITAV_push0_stack_item
- OSSL_CMP_ITAV utility functions

=head1 SYNOPSIS

  #include <openssl/cmp.h>
  OSSL_CMP_ITAV *OSSL_CMP_ITAV_create(ASN1_OBJECT *type, ASN1_TYPE *value);
  void OSSL_CMP_ITAV_set0(OSSL_CMP_ITAV *itav, ASN1_OBJECT *type,
                          ASN1_TYPE *value);
  ASN1_OBJECT *OSSL_CMP_ITAV_get0_type(const OSSL_CMP_ITAV *itav);
  ASN1_TYPE *OSSL_CMP_ITAV_get0_value(const OSSL_CMP_ITAV *itav);

  int OSSL_CMP_ITAV_push0_stack_item(STACK_OF(OSSL_CMP_ITAV) **itav_sk_p,
                                     OSSL_CMP_ITAV *itav);

=head1 DESCRIPTION

Certificate Management Protocol (CMP, RFC 4210) extension to OpenSSL

ITAV is short for InfoTypeAndValue. This type is defined in RFC 4210
section 5.3.19 and Appendix F. It is used at various places in CMP messages,
e.g., in the generalInfo PKIHeader field, to hold a key-value pair.

OSSL_CMP_ITAV_create() creates a new B<OSSL_CMP_ITAV> structure and fills it in.
It combines OSSL_CMP_ITAV_new() and OSSL_CMP_ITAV_set0().

OSSL_CMP_ITAV_set0() sets the I<itav> with an infoType of I<type> and an
infoValue of I<value>. This function uses the pointers I<type> and I<value>
internally, so they must B<not> be freed up after the call.

OSSL_CMP_ITAV_get0_type() returns a direct pointer to the infoType in the
I<itav>.

OSSL_CMP_ITAV_get0_value() returns a direct pointer to the infoValue in
the I<itav> as generic B<ASN1_TYPE> pointer.

OSSL_CMP_ITAV_push0_stack_item() pushes I<itav> to the stack pointed to
by I<*itav_sk_p>. It creates a new stack if I<*itav_sk_p> points to NULL.

=head1 NOTES

CMP is defined in RFC 4210 (and CRMF in RFC 4211).

=head1 RETURN VALUES

OSSL_CMP_ITAV_create() returns a pointer to the ITAV structure on success,
or NULL on error.

OSSL_CMP_ITAV_set0() does not return a value.

OSSL_CMP_ITAV_get0_type() and OSSL_CMP_ITAV_get0_value()
return the respective pointer or NULL if their input is NULL.

OSSL_CMP_ITAV_push0_stack_item() returns 1 on success, 0 on error.

=head1 EXAMPLES

The following code creates and sets a structure representing a generic
InfoTypeAndValue sequence, using an OID created from text as type, and an
integer as value. Afterwards, it is pushed to the B<OSSL_CMP_CTX> to be later
included in the requests' PKIHeader's genInfo field.

    ASN1_OBJECT *type = OBJ_txt2obj("1.2.3.4.5", 1);
    if (type == NULL) ...

    ASN1_INTEGER *asn1int = ASN1_INTEGER_new();
    if (asn1int == NULL || !ASN1_INTEGER_set(asn1int, 12345)) ...

    ASN1_TYPE *val = ASN1_TYPE_new();
    if (val == NULL) ...
    ASN1_TYPE_set(val, V_ASN1_INTEGER, asn1int);

    OSSL_CMP_ITAV *itav = OSSL_CMP_ITAV_create(type, val);
    if (itav == NULL) ...

    OSSL_CMP_CTX *ctx = OSSL_CMP_CTX_new();
    if (ctx == NULL || !OSSL_CMP_CTX_geninfo_push0_ITAV(ctx, itav)) {
        OSSL_CMP_ITAV_free(itav); /* also frees type and val */
        goto err;
    }

    ...

    OSSL_CMP_CTX_free(ctx); /* also frees itav */

=head1 SEE ALSO

L<OSSL_CMP_CTX_new(3)>, L<OSSL_CMP_CTX_free(3)>, L<ASN1_TYPE_set(3)>

=head1 HISTORY

The OpenSSL CMP support was added in OpenSSL 3.0.

=head1 COPYRIGHT

Copyright 2007-2021 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the Apache License 2.0 (the "License").  You may not use
this file except in compliance with the License.  You can obtain a copy
in the file LICENSE in the source distribution or at
L<https://www.openssl.org/source/license.html>.

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