NAME

       SSL_CTX_set_timeout, SSL_CTX_get_timeout - manipulate timeout values for session caching

SYNOPSIS

        #include <openssl/ssl.h>

        long SSL_CTX_set_timeout(SSL_CTX *ctx, long t);
        long SSL_CTX_get_timeout(SSL_CTX *ctx);

DESCRIPTION

       SSL_CTX_set_timeout() sets the timeout for newly created sessions for ctx to t. The
       timeout value t must be given in seconds.

       SSL_CTX_get_timeout() returns the currently set timeout value for ctx.

NOTES

       Whenever a new session is created, it is assigned a maximum lifetime. This lifetime is
       specified by storing the creation time of the session and the timeout value valid at this
       time. If the actual time is later than creation time plus timeout, the session is not
       reused.

       Due to this realization, all sessions behave according to the timeout value valid at the
       time of the session negotiation. Changes of the timeout value do not affect already
       established sessions.

       The expiration time of a single session can be modified using the SSL_SESSION_get_time(3)
       family of functions.

       Expired sessions are removed from the internal session cache, whenever
       SSL_CTX_flush_sessions(3) is called, either directly by the application or automatically
       (see SSL_CTX_set_session_cache_mode(3))

       The default value for session timeout is decided on a per protocol basis, see
       SSL_get_default_timeout(3).  All currently supported protocols have the same default
       timeout value of 300 seconds.

       This timeout value is used as the ticket lifetime hint for stateless session tickets. It
       is also used as the timeout value within the ticket itself.

       For TLSv1.3, RFC8446 limits transmission of this value to 1 week (604800 seconds).

       For TLSv1.2, tickets generated during an initial handshake use the value as specified.
       Tickets generated during a resumed handshake have a value of 0 for the ticket lifetime
       hint.

RETURN VALUES

       SSL_CTX_set_timeout() returns the previously set timeout value.

       SSL_CTX_get_timeout() returns the currently set timeout value.

SEE ALSO

       ssl(7), SSL_CTX_set_session_cache_mode(3), SSL_SESSION_get_time(3),
       SSL_CTX_flush_sessions(3), SSL_get_default_timeout(3)

COPYRIGHT

       Copyright 2001-2022 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 <https://www.openssl.org/source/license.html>.