=pod

=head1 NAME

SSL_CTX_set_ssl_version, SSL_CTX_get_ssl_method, SSL_set_ssl_method, SSL_get_ssl_method
- choose a new TLS/SSL method

=head1 SYNOPSIS

 #include <openssl/ssl.h>

 int SSL_CTX_set_ssl_version(SSL_CTX *ctx, const SSL_METHOD *method);
 const SSL_METHOD *SSL_CTX_get_ssl_method(const SSL_CTX *ctx);

 int SSL_set_ssl_method(SSL *s, const SSL_METHOD *method);
 const SSL_METHOD *SSL_get_ssl_method(const SSL *ssl);

=head1 DESCRIPTION

SSL_CTX_set_ssl_version() sets a new default TLS/SSL B<method> for SSL objects
newly created from this B<ctx>.  Most of the configuration attached to the
SSL_CTX object is retained, with the exception of the configured TLS ciphers,
which are reset to the default values.  SSL objects already created from this
SSL_CTX with L<SSL_new(3)> are not affected, except when L<SSL_clear(3)> is
being called, as described below.

SSL_CTX_get_ssl_method() returns the SSL_METHOD which was used to construct the
SSL_CTX.

SSL_set_ssl_method() sets a new TLS/SSL B<method> for a particular B<ssl>
object. It may be reset, when SSL_clear() is called.

SSL_get_ssl_method() returns a pointer to the TLS/SSL method
set in B<ssl>.

=head1 NOTES

The available B<method> choices are described in
L<SSL_CTX_new(3)>.

When L<SSL_clear(3)> is called and no session is connected to
an SSL object, the method of the SSL object is reset to the method currently
set in the corresponding SSL_CTX object.

SSL_CTX_set_version() has unusual semantics and no clear use case;
it would usually be preferable to create a new SSL_CTX object than to
try to reuse an existing one in this fashion.  Its usage is considered
deprecated.

SSL_set_ssl_method() cannot be used to change a non-QUIC SSL object to a QUIC
SSL object or vice versa, or change a QUIC SSL object from one QUIC method to
another.

=head1 RETURN VALUES

The following return values can occur for SSL_CTX_set_ssl_version()
and SSL_set_ssl_method():

=over 4

=item Z<>0

The new choice failed, check the error stack to find out the reason.

=item Z<>1

The operation succeeded.

=back

SSL_CTX_get_ssl_method() and SSL_get_ssl_method() always return non-NULL
pointers.

=head1 SEE ALSO

L<SSL_CTX_new(3)>, L<SSL_new(3)>,
L<SSL_clear(3)>, L<ssl(7)>,
L<SSL_set_connect_state(3)>

=head1 HISTORY

SSL_CTX_set_ssl_version() was deprecated in OpenSSL 3.0.

=head1 COPYRIGHT

Copyright 2000-2023 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