1=pod 2 3=head1 NAME 4 5SSL_CTX_set_timeout, SSL_CTX_get_timeout - manipulate timeout values for session caching 6 7=head1 SYNOPSIS 8 9 #include <openssl/ssl.h> 10 11 long SSL_CTX_set_timeout(SSL_CTX *ctx, long t); 12 long SSL_CTX_get_timeout(SSL_CTX *ctx); 13 14=head1 DESCRIPTION 15 16SSL_CTX_set_timeout() sets the timeout for newly created sessions for 17B<ctx> to B<t>. The timeout value B<t> must be given in seconds. 18 19SSL_CTX_get_timeout() returns the currently set timeout value for B<ctx>. 20 21=head1 NOTES 22 23Whenever a new session is created, it is assigned a maximum lifetime. This 24lifetime is specified by storing the creation time of the session and the 25timeout value valid at this time. If the actual time is later than creation 26time plus timeout, the session is not reused. 27 28Due to this realization, all sessions behave according to the timeout value 29valid at the time of the session negotiation. Changes of the timeout value 30do not affect already established sessions. 31 32The expiration time of a single session can be modified using the 33L<SSL_SESSION_get_time(3)> family of functions. 34 35Expired sessions are removed from the internal session cache, whenever 36L<SSL_CTX_flush_sessions(3)> is called, either 37directly by the application or automatically (see 38L<SSL_CTX_set_session_cache_mode(3)>) 39 40The default value for session timeout is decided on a per protocol 41basis, see L<SSL_get_default_timeout(3)>. 42All currently supported protocols have the same default timeout value 43of 300 seconds. 44 45This timeout value is used as the ticket lifetime hint for stateless session 46tickets. It is also used as the timeout value within the ticket itself. 47 48For TLSv1.3, RFC8446 limits transmission of this value to 1 week (604800 49seconds). 50 51For TLSv1.2, tickets generated during an initial handshake use the value 52as specified. Tickets generated during a resumed handshake have a value 53of 0 for the ticket lifetime hint. 54 55=head1 RETURN VALUES 56 57SSL_CTX_set_timeout() returns the previously set timeout value. 58 59SSL_CTX_get_timeout() returns the currently set timeout value. 60 61=head1 SEE ALSO 62 63L<ssl(7)>, 64L<SSL_CTX_set_session_cache_mode(3)>, 65L<SSL_SESSION_get_time(3)>, 66L<SSL_CTX_flush_sessions(3)>, 67L<SSL_get_default_timeout(3)> 68 69=head1 COPYRIGHT 70 71Copyright 2001-2022 The OpenSSL Project Authors. All Rights Reserved. 72 73Licensed under the Apache License 2.0 (the "License"). You may not use 74this file except in compliance with the License. You can obtain a copy 75in the file LICENSE in the source distribution or at 76L<https://www.openssl.org/source/license.html>. 77 78=cut 79