Scroll to navigation



SSL_CTX_add_session, SSL_CTX_remove_session - manipulate session cache


 #include <openssl/ssl.h>
 int SSL_CTX_add_session(SSL_CTX *ctx, SSL_SESSION *c);
 int SSL_CTX_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 and marks it as non-resumable. SSL_SESSION_free(3) is called once for c.


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.


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.


ssl(7), SSL_CTX_set_session_cache_mode(3), SSL_SESSION_free(3)


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

Licensed under the Apache License 2.0 (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 <>.

2024-06-04 3.3.1