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(const 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() creates a new SSL_SESSION structure that is a copy of src.  The copy is
       not owned by any cache that src may have been in.

       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_dup returns a pointer to the new copy 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 2000-2023 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>.