Rework the documentation of our individual MAC implementations

We now describe parameters instead of controls.

Also, since macros like EVP_MAC_CMAC do not exist any more, we rename
the pod files from EVP_MAC_{algo}.pod to EVP_MAC-{algo}.pod.  This
allows getting the documentation like this:

    man EVP_MAC CMAC

[skip ci]
Fixes #9709

Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/9713)

1 files changed, 70 insertions, 0 deletions

diff --git a/doc/man7/EVP_MAC-HMAC.pod b/doc/man7/EVP_MAC-HMAC.pod
new file mode 100644
index 0000000000..0fb92d329e
--- /dev/null
+++ b/doc/man7/EVP_MAC-HMAC.pod
@@ -0,0 +1,70 @@
+=pod
+
+=head1 NAME
+
+EVP_MAC-HMAC - The HMAC EVP_MAC implementation
+
+=head1 DESCRIPTION
+
+Support for computing HMAC MACs through the B<EVP_MAC> API.
+
+=head2 Identity
+
+This implementation is identified with this name and properties, to be
+used with EVP_MAC_fetch():
+
+=over 4
+
+=item "HMAC", "default=yes"
+
+=back
+
+=head2 Supported parameters
+
+The general description of these parameters can be found in
+L<EVP_MAC(3)/PARAMETER NAMES>.
+
+The following parameter can be set with EVP_MAC_CTX_set_params():
+
+=over 4
+
+=item B<OSSL_MAC_PARAM_KEY> ("key") <octet string>
+
+=item B<OSSL_MAC_PARAM_FLAGS> ("flags") <octet string>
+
+=item B<OSSL_MAC_PARAM_ENGINE> ("engine") <utf8 string>
+
+=item B<OSSL_MAC_PARAM_DIGEST> ("digest") <utf8 string>
+
+=item B<OSSL_MAC_PARAM_PROPERTIES> ("properties") <utf8 string>
+
+=back
+
+The "flags" parameter is passed directly to HMAC_CTX_set_flags().
+
+The following parameters can be retrieved with
+EVP_MAC_CTX_get_params():
+
+=over 4
+
+=item B<OSSL_MAC_PARAM_SIZE> ("size") <unsigned int>
+
+=back
+
+The "size" parameter can also be retrieved with EVP_MAC_size().
+
+=head1 SEE ALSO
+
+L<EVP_MAC_CTX_get_params(3)>, L<EVP_MAC_CTX_set_params(3)>,
+L<EVP_MAC(3)/PARAMETER NAMES>, L<OSSL_PARAM(3)>, L<HMAC(3)>
+
+=head1 COPYRIGHT
+
+Copyright 2018-2019 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>.
+
+=cut