1SSL_CTX_sess_set_get_cb(3) OpenSSL SSL_CTX_sess_set_get_cb(3)
2
6 SSL_CTX_sess_set_new_cb, SSL_CTX_sess_set_remove_cb,
7 SSL_CTX_sess_set_get_cb, SSL_CTX_sess_get_new_cb,
8 SSL_CTX_sess_get_remove_cb, SSL_CTX_sess_get_get_cb - provide callback
9 functions for server side external session caching
10
12 #include <openssl/ssl.h>
13 void SSL_CTX_sess_set_new_cb(SSL_CTX *ctx,
15 int (*new_session_cb)(SSL *, SSL_SESSION *));
16 void SSL_CTX_sess_set_remove_cb(SSL_CTX *ctx,
17 void (*remove_session_cb)(SSL_CTX *ctx, SSL_SESSION *));
18 void SSL_CTX_sess_set_get_cb(SSL_CTX *ctx,
19 SSL_SESSION (*get_session_cb)(SSL *, unsigned char *, int, int *));
20 int (*SSL_CTX_sess_get_new_cb(SSL_CTX *ctx))(struct ssl_st *ssl, SSL_SESSION *sess);
22 void (*SSL_CTX_sess_get_remove_cb(SSL_CTX *ctx))(struct ssl_ctx_st *ctx, SSL_SESSION *sess);
23 SSL_SESSION *(*SSL_CTX_sess_get_get_cb(SSL_CTX *ctx))(struct ssl_st *ssl, unsigned char *data, int len, int *copy);
24 int (*new_session_cb)(struct ssl_st *ssl, SSL_SESSION *sess);
26 void (*remove_session_cb)(struct ssl_ctx_st *ctx, SSL_SESSION *sess);
27 SSL_SESSION *(*get_session_cb)(struct ssl_st *ssl, unsigned char *data,
28 int len, int *copy);
29
31 SSL_CTX_sess_set_new_cb() sets the callback function, which is
32 automatically called whenever a new session was negotiated.
33 SSL_CTX_sess_set_remove_cb() sets the callback function, which is
35 automatically called whenever a session is removed by the SSL engine,
36 because it is considered faulty or the session has become obsolete
37 because of exceeding the timeout value.
38 SSL_CTX_sess_set_get_cb() sets the callback function which is called,
40 whenever a SSL/TLS client proposed to resume a session but the session
41 could not be found in the internal session cache (see
42 SSL_CTX_set_session_cache_mode(3)). (SSL/TLS server only.)
43 SSL_CTX_sess_get_new_cb(), SSL_CTX_sess_get_remove_cb(), and
45 SSL_CTX_sess_get_get_cb() allow to retrieve the function pointers of
46 the provided callback functions. If a callback function has not been
47 set, the NULL pointer is returned.
48
50 In order to allow external session caching, synchronization with the
51 internal session cache is realized via callback functions. Inside these
52 callback functions, session can be saved to disk or put into a database
53 using the d2i_SSL_SESSION(3) interface.
54 The new_session_cb() is called, whenever a new session has been
56 negotiated and session caching is enabled (see
57 SSL_CTX_set_session_cache_mode(3)). The new_session_cb() is passed the
58 ssl connection and the ssl session sess. If the callback returns 0, the
59 session will be immediately removed again.
60 The remove_session_cb() is called, whenever the SSL engine removes a
62 session from the internal cache. This happens when the session is
63 removed because it is expired or when a connection was not shutdown
64 cleanly. It also happens for all sessions in the internal session cache
65 when SSL_CTX_free(3) is called. The remove_session_cb() is passed the
66 ctx and the ssl session sess. It does not provide any feedback.
67 The get_session_cb() is only called on SSL/TLS servers with the session
69 id proposed by the client. The get_session_cb() is always called, also
70 when session caching was disabled. The get_session_cb() is passed the
71 ssl connection, the session id of length length at the memory location
72 data. With the parameter copy the callback can require the SSL engine
73 to increment the reference count of the SSL_SESSION object, Normally
74 the reference count is not incremented and therefore the session must
75 not be explicitly freed with SSL_SESSION_free(3).
76
78 ssl(3), d2i_SSL_SESSION(3), SSL_CTX_set_session_cache_mode(3),
79 SSL_CTX_flush_sessions(3), SSL_SESSION_free(3), SSL_CTX_free(3)
801.0.2o 2019-09-10 SSL_CTX_sess_set_get_cb(3)