SSL_SESSION_free(3) OpenSSL SSL_SESSION_free(3)
NAME
SSL_SESSION_free - free an allocated SSL_SESSION structure
SYNOPSIS
#include <openssl/ssl.h>
void SSL_SESSION_free(SSL_SESSION *session);
DESCRIPTION
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 the reference count has reached 0.
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_free() does not provide diagnostic information.
SEE ALSO
ssl(3), SSL_get_session(3), SSL_CTX_set_session_cache_mode(3), SSL_CTX_flush_sessions(3),
d2i_SSL_SESSION(3)
0.9.7l 2001-10-12 SSL_SESSION_free(3)
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