NAME¶
SSL_get_session - retrieve TLS/SSL session data
SYNOPSIS¶
#include <openssl/ssl.h>
SSL_SESSION *SSL_get_session(const SSL *ssl);
SSL_SESSION *SSL_get0_session(const SSL *ssl);
SSL_SESSION *SSL_get1_session(SSL *ssl);
DESCRIPTION¶
SSL_get_session() returns a pointer to the
SSL_SESSION actually
used in
ssl. The reference count of the
SSL_SESSION is not
incremented, so that the pointer can become invalid by other operations.
SSL_get0_session() is the same as
SSL_get_session().
SSL_get1_session() is the same as
SSL_get_session(), but the
reference count of the
SSL_SESSION is incremented by one.
NOTES¶
The ssl session contains all information required to re-establish the connection
without a new handshake.
SSL_get0_session() returns a pointer to the actual session. As the
reference counter is not incremented, the pointer is only valid while the
connection is in use. If
SSL_clear(3) or
SSL_free(3) is called,
the session may be removed completely (if considered bad), and the pointer
obtained will become invalid. Even if the session is valid, it can be removed
at any time due to timeout during
SSL_CTX_flush_sessions(3).
If the data is to be kept,
SSL_get1_session() will increment the
reference count, so that the session will not be implicitly removed by other
operations but stays in memory. In order to remove the session
SSL_SESSION_free(3) must be explicitly called once to decrement the
reference count again.
SSL_SESSION objects keep internal link information about the session cache list,
when being inserted into one SSL_CTX object's session cache. One SSL_SESSION
object, regardless of its reference count, must therefore only be used with
one SSL_CTX object (and the SSL objects created from this SSL_CTX object).
RETURN VALUES¶
The following return values can occur:
- NULL
- There is no session available in ssl.
- Pointer to an SSL
- The return value points to the data of an SSL session.
SEE ALSO¶
ssl(3),
SSL_free(3),
SSL_clear(3),
SSL_SESSION_free(3)