SSL_CTX_add_session.3ssl man page

SSL_CTX_add_session, SSL_add_session, SSL_CTX_remove_session, SSL_remove_session — manipulate session cache


 #include <openssl/ssl.h>
 int SSL_CTX_add_session(SSL_CTX *ctx, SSL_SESSION *c);
 int SSL_add_session(SSL_CTX *ctx, SSL_SESSION *c);
 int SSL_CTX_remove_session(SSL_CTX *ctx, SSL_SESSION *c);
 int SSL_remove_session(SSL_CTX *ctx, SSL_SESSION *c);


SSL_CTX_add_session() adds the session c to the context ctx. The reference count for session c is incremented by 1. If a session with the same session id already exists, the old session is removed by calling SSL_SESSION_free(3).

SSL_CTX_remove_session() removes the session c from the context ctx. SSL_SESSION_free(3) is called once for c.

SSL_add_session() and SSL_remove_session() are synonyms for their SSL_CTX_*() counterparts.


When adding a new session to the internal session cache, it is examined whether a session with the same session id already exists. In this case it is assumed that both sessions are identical. If the same session is stored in a different SSL_SESSION object, The old session is removed and replaced by the new session. If the session is actually identical (the SSL_SESSION object is identical), SSL_CTX_add_session() is a no-op, and the return value is 0.

If a server SSL_CTX is configured with the SSL_SESS_CACHE_NO_INTERNAL_STORE flag then the internal cache will not be populated automatically by new sessions negotiated by the SSL/TLS implementation, even though the internal cache will be searched automatically for session-resume requests (the latter can be suppressed by SSL_SESS_CACHE_NO_INTERNAL_LOOKUP). So the application can use SSL_CTX_add_session() directly to have full control over the sessions that can be resumed if desired.

Return Values

The following values are returned by all functions:

 The operation failed. In case of the add operation, it was tried to add
 the same (identical) session twice. In case of the remove operation, the
 session was not found in the cache.
 The operation succeeded.

See Also

ssl(3), SSL_CTX_set_session_cache_mode(3), SSL_SESSION_free(3)


2016-09-26 1.0.2j OpenSSL