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SSL_CTX_sess_set_get_cb(3)                         OpenSSL                        SSL_CTX_sess_set_get_cb(3)



NAME
       SSL_CTX_sess_set_new_cb, SSL_CTX_sess_set_remove_cb, SSL_CTX_sess_set_get_cb,
       SSL_CTX_sess_get_new_cb, SSL_CTX_sess_get_remove_cb, SSL_CTX_sess_get_get_cb - provide callback
       functions for server side external session caching

SYNOPSIS
        #include <openssl/ssl.h>

        void SSL_CTX_sess_set_new_cb(SSL_CTX *ctx,
                                     int (*new_session_cb)(SSL *, SSL_SESSION *));
        void SSL_CTX_sess_set_remove_cb(SSL_CTX *ctx,
                  void (*remove_session_cb)(SSL_CTX *ctx, SSL_SESSION *));
        void SSL_CTX_sess_set_get_cb(SSL_CTX *ctx,
                  SSL_SESSION (*get_session_cb)(SSL *, unsigned char *, int, int *));

        int (*SSL_CTX_sess_get_new_cb(SSL_CTX *ctx))(struct ssl_st *ssl, SSL_SESSION *sess);
        void (*SSL_CTX_sess_get_remove_cb(SSL_CTX *ctx))(struct ssl_ctx_st *ctx, SSL_SESSION *sess);
        SSL_SESSION *(*SSL_CTX_sess_get_get_cb(SSL_CTX *ctx))(struct ssl_st *ssl, unsigned char *data, int len, int *copy);

        int (*new_session_cb)(struct ssl_st *ssl, SSL_SESSION *sess);
        void (*remove_session_cb)(struct ssl_ctx_st *ctx, SSL_SESSION *sess);
        SSL_SESSION *(*get_session_cb)(struct ssl_st *ssl, unsigned char *data,
                      int len, int *copy);

DESCRIPTION
       SSL_CTX_sess_set_new_cb() sets the callback function, which is automatically called whenever a new
       session was negotiated.

       SSL_CTX_sess_set_remove_cb() sets the callback function, which is automatically called whenever a
       session is removed by the SSL engine, because it is considered faulty or the session has become
       obsolete because of exceeding the timeout value.

       SSL_CTX_sess_set_get_cb() sets the callback function which is called, whenever a SSL/TLS client
       proposed to resume a session but the session could not be found in the internal session cache (see
       SSL_CTX_set_session_cache_mode(3)).  (SSL/TLS server only.)

       SSL_CTX_sess_get_new_cb(), SSL_CTX_sess_get_remove_cb(), and SSL_CTX_sess_get_get_cb() allow to
       retrieve the function pointers of the provided callback functions. If a callback function has not
       been set, the NULL pointer is returned.

NOTES
       In order to allow external session caching, synchronization with the internal session cache is
       realized via callback functions. Inside these callback functions, session can be saved to disk or put
       into a database using the d2i_SSL_SESSION(3) interface.

       The new_session_cb() is called, whenever a new session has been negotiated and session caching is
       enabled (see SSL_CTX_set_session_cache_mode(3)).  The new_session_cb() is passed the ssl connection
       and the ssl session sess. If the callback returns 0, the session will be immediately removed again.

       The remove_session_cb() is called, whenever the SSL engine removes a session from the internal cache.
       This happens when the session is removed because it is expired or when a connection was not shutdown
       cleanly. It also happens for all sessions in the internal session cache when SSL_CTX_free(3) is
       called. The remove_session_cb() is passed the ctx and the ssl session sess. It does not provide any
       feedback.

       The get_session_cb() is only called on SSL/TLS servers with the session id proposed by the client.
       The get_session_cb() is always called, also when session caching was disabled. The get_session_cb()
       is passed the ssl connection, the session id of length length at the memory location data. With the
       parameter copy the callback can require the SSL engine to increment the reference count of the
       SSL_SESSION object, Normally the reference count is not incremented and therefore the session must
       not be explicitly freed with SSL_SESSION_free(3).

SEE ALSO
       ssl(3), d2i_SSL_SESSION(3), SSL_CTX_set_session_cache_mode(3), SSL_CTX_flush_sessions(3),
       SSL_SESSION_free(3), SSL_CTX_free(3)



0.9.8                                            2009-04-03                       SSL_CTX_sess_set_get_cb(3)