- NAME
- SYNOPSIS
- DESCRIPTION
- NOTES
- SEE ALSO
- COPYRIGHT

# 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 *, const 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, const 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 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 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_SESSION_free(3).

# SEE ALSO

d2i_SSL_SESSION(3), SSL_CTX_flush_sessions(3), SSL_CTX_free(3)

# COPYRIGHT

Copyright 2001-2016 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the OpenSSL license (the "License"). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at https://www.openssl.org/source/license.html.