SSL_get_default_timeout() returns the default timeout value assigned to
SSL_SESSION objects negotiated for the protocol valid for ssl.
NOTES
Whenever a new session is negotiated, it is assigned a timeout value,
after which it will not be accepted for session reuse. If the timeout
value was not explicitly set using
SSL_CTX_set_timeout(3), the hardcoded default
timeout for the protocol will be used.
SSL_get_default_timeout() return this hardcoded value, which is 300 seconds
for all currently supported protocols (SSLv2, SSLv3, and TLSv1).
