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);
DESCRIPTIONSSL_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 if
the session is removed because it is expired or when a
connection was not shutdown cleanly. 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 ALSOssl(3), d2i_SSL_SESSION(3),
SSL_CTX_set_session_cache_mode(3),
SSL_CTX_flush_sessions(3), SSL_SESSION_free(3)10/Jul/2002 0.9.6j SSL_CTX_sess_set_get_cb(3)
