Initial Commit

openssl-1.0.2f/doc/ssl/SSL_get_session.pod

@@ -0,0 +1,73 @@
+=pod
+
+=head1 NAME
+
+SSL_get_session - retrieve TLS/SSL session data
+
+=head1 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);
+
+=head1 DESCRIPTION
+
+SSL_get_session() returns a pointer to the B<SSL_SESSION> actually used in
+B<ssl>. The reference count of the B<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 B<SSL_SESSION> is incremented by one.
+
+=head1 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 L<SSL_clear(3)|SSL_clear(3)> or
+L<SSL_free(3)|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 L<SSL_CTX_flush_sessions(3)|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
+L<SSL_SESSION_free(3)|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).
+
+=head1 RETURN VALUES
+
+The following return values can occur:
+
+=over 4
+
+=item NULL
+
+There is no session available in B<ssl>.
+
+=item Pointer to an SSL
+
+The return value points to the data of an SSL session.
+
+=back
+
+=head1 SEE ALSO
+
+L<ssl(3)|ssl(3)>, L<SSL_free(3)|SSL_free(3)>,
+L<SSL_clear(3)|SSL_clear(3)>,
+L<SSL_SESSION_free(3)|SSL_SESSION_free(3)>
+
+=cut