/usr/man/cat.3/SSL_CTX_sess_get_remove_cb.3

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

1.0.2t               Last change: 2019-09-10                    1

SSL_CTX_sess_set_get_cb(3)   OpenSSL   SSL_CTX_sess_set_get_cb(3)

     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)

1.0.2t               Last change: 2019-09-10                    2

See also SSL_CTX_sess_get_get_cb(3)
See also SSL_CTX_sess_get_new_cb(3)
See also SSL_CTX_sess_set_get_cb(3)
See also SSL_CTX_sess_set_new_cb(3)
See also SSL_CTX_sess_set_remove_cb(3)