opnsense-src/crypto/openssl/doc/man3/SSL_alloc_buffers.pod
Pierre Pronchery b077aed33b Merge OpenSSL 3.0.9
Migrate to OpenSSL 3.0 in advance of FreeBSD 14.0.  OpenSSL 1.1.1 (the
version we were previously using) will be EOL as of 2023-09-11.

Most of the base system has already been updated for a seamless switch
to OpenSSL 3.0.  For many components we've added
`-DOPENSSL_API_COMPAT=0x10100000L` to CFLAGS to specify the API version,
which avoids deprecation warnings from OpenSSL 3.0.  Changes have also
been made to avoid OpenSSL APIs that were already deprecated in OpenSSL
1.1.1.  The process of updating to contemporary APIs can continue after
this merge.

Additional changes are still required for libarchive and Kerberos-
related libraries or tools; workarounds will immediately follow this
commit.  Fixes are in progress in the upstream projects and will be
incorporated when those are next updated.

There are some performance regressions in benchmarks (certain tests in
`openssl speed`) and in some OpenSSL consumers in ports (e.g.  haproxy).
Investigation will continue for these.

Netflix's testing showed no functional regression and a rather small,
albeit statistically significant, increase in CPU consumption with
OpenSSL 3.0.

Thanks to ngie@ and des@ for updating base system components, to
antoine@ and bofh@ for ports exp-runs and port fixes/workarounds, and to
Netflix and everyone who tested prior to commit or contributed to this
update in other ways.

PR:		271615
PR:		271656 [exp-run]
Relnotes:	Yes
Sponsored by:	The FreeBSD Foundation
2023-06-23 18:53:36 -04:00

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=pod
=head1 NAME
SSL_free_buffers, SSL_alloc_buffers - manage SSL structure buffers
=head1 SYNOPSIS
#include <openssl/ssl.h>
int SSL_free_buffers(SSL *ssl);
int SSL_alloc_buffers(SSL *ssl);
=head1 DESCRIPTION
SSL_free_buffers() frees the read and write buffers of the given B<ssl>.
SSL_alloc_buffers() allocates the read and write buffers of the given B<ssl>.
The B<SSL_MODE_RELEASE_BUFFERS> mode releases read or write buffers whenever
the buffers have been drained. These functions allow applications to manually
control when buffers are freed and allocated.
After freeing the buffers, the buffers are automatically reallocated upon a
new read or write. The SSL_alloc_buffers() does not need to be called, but
can be used to make sure the buffers are preallocated. This can be used to
avoid allocation during data processing or with CRYPTO_set_mem_functions()
to control where and how buffers are allocated.
=head1 RETURN VALUES
The following return values can occur:
=over 4
=item 0 (Failure)
The SSL_free_buffers() function returns 0 when there is pending data to be
read or written. The SSL_alloc_buffers() function returns 0 when there is
an allocation failure.
=item 1 (Success)
The SSL_free_buffers() function returns 1 if the buffers have been freed. This
value is also returned if the buffers had been freed before calling
SSL_free_buffers().
The SSL_alloc_buffers() function returns 1 if the buffers have been allocated.
This value is also returned if the buffers had been allocated before calling
SSL_alloc_buffers().
=back
=head1 SEE ALSO
L<ssl(7)>,
L<SSL_free(3)>, L<SSL_clear(3)>,
L<SSL_new(3)>, L<SSL_CTX_set_mode(3)>,
L<CRYPTO_set_mem_functions(3)>
=head1 COPYRIGHT
Copyright 2017-2020 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