NAME

       SSL_SESSION_new, SSL_SESSION_dup, SSL_SESSION_up_ref, SSL_SESSION_free - create, free and
       manage SSL_SESSION structures

SYNOPSIS

        #include <openssl/ssl.h>

        SSL_SESSION *SSL_SESSION_new(void);
        SSL_SESSION *SSL_SESSION_dup(SSL_SESSION *src);
        int SSL_SESSION_up_ref(SSL_SESSION *ses);
        void SSL_SESSION_free(SSL_SESSION *session);

DESCRIPTION

       SSL_SESSION_new() creates a new SSL_SESSION structure and returns a pointer to it.

       SSL_SESSION_dup() copies the contents of the SSL_SESSION structure in src and returns a
       pointer to it.

       SSL_SESSION_up_ref() increments the reference count on the given SSL_SESSION structure.

       SSL_SESSION_free() decrements the reference count of session and removes the SSL_SESSION
       structure pointed to by session and frees up the allocated memory, if the reference count
       has reached 0.  If session is NULL nothing is done.

NOTES

       SSL_SESSION objects are allocated, when a TLS/SSL handshake operation is successfully
       completed. Depending on the settings, see SSL_CTX_set_session_cache_mode(3), the
       SSL_SESSION objects are internally referenced by the SSL_CTX and linked into its session
       cache. SSL objects may be using the SSL_SESSION object; as a session may be reused,
       several SSL objects may be using one SSL_SESSION object at the same time. It is therefore
       crucial to keep the reference count (usage information) correct and not delete a
       SSL_SESSION object that is still used, as this may lead to program failures due to
       dangling pointers. These failures may also appear delayed, e.g.  when an SSL_SESSION
       object was completely freed as the reference count incorrectly became 0, but it is still
       referenced in the internal session cache and the cache list is processed during a
       SSL_CTX_flush_sessions(3) operation.

       SSL_SESSION_free() must only be called for SSL_SESSION objects, for which the reference
       count was explicitly incremented (e.g.  by calling SSL_get1_session(), see
       SSL_get_session(3)) or when the SSL_SESSION object was generated outside a TLS handshake
       operation, e.g. by using d2i_SSL_SESSION(3).  It must not be called on other SSL_SESSION
       objects, as this would cause incorrect reference counts and therefore program failures.

RETURN VALUES

       SSL_SESSION_new returns a pointer to the newly allocated SSL_SESSION structure or NULL on
       error.

       SSL_SESSION_up_ref returns 1 on success or 0 on error.

SEE ALSO

       ssl(7), SSL_get_session(3), SSL_CTX_set_session_cache_mode(3), SSL_CTX_flush_sessions(3),
       d2i_SSL_SESSION(3)

HISTORY

       The SSL_SESSION_dup() function was added in OpenSSL 1.1.1.

COPYRIGHT

       Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the OpenSSL license (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>.