SSL_CTX_set_timeout, SSL_CTX_get_timeout - manipulate timeout values for session caching
long SSL_CTX_set_timeout(SSL_CTX *ctx, long t); long SSL_CTX_get_timeout(SSL_CTX *ctx);
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.
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.