NAME    [Toc]    [Back]

       SSL_CTX_sess_set_get_cb,          SSL_CTX_sess_set_new_cb,
       SSL_CTX_sess_set_remove_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    [Toc]    [Back]

       #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    [Toc]    [Back]

       The SSL_CTX_sess_set_get_cb() function sets  the  callback
       function  which  is called whenever an SSL/TLS client proposes
 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.)

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

       The SSL_CTX_sess_set_remove_cb() function 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.

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

NOTES    [Toc]    [Back]

       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() function 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()
  function  is  passed the ssl connection and the
       ssl session sess.  If the callback returns 0, the  session
       will be removed immediately.

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

       The get_session_cb() function is only  called  on  SSL/TLS
       servers  with  the  session id proposed by the client. The
       get_session_cb() function is always called, also when session
  caching  is disabled.  The get_session_cb() function
       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().

SEE ALSO    [Toc]    [Back]

       Functions:  ssl(3),  d2i_SSL_SESSION(3),  SSL_CTX_set_session_cache_mode(3),   SSL_CTX_flush_sessions(3),  SSL_SESSION_free(3)



                                       SSL_CTX_sess_set_get_cb(3)