| SSL_CTX_set_session_cache_mode.pod (89837) | SSL_CTX_set_session_cache_mode.pod (109998) |
|---|---|
| 1=pod 2 3=head1 NAME 4 5SSL_CTX_set_session_cache_mode, SSL_CTX_get_session_cache_mode - enable/disable session caching 6 7=head1 SYNOPSIS 8 --- 12 unchanged lines hidden (view full) --- 21=head1 NOTES 22 23The OpenSSL library can store/retrieve SSL/TLS sessions for later reuse. 24The sessions can be held in memory for each B<ctx>, if more than one 25SSL_CTX object is being maintained, the sessions are unique for each SSL_CTX 26object. 27 28In order to reuse a session, a client must send the session's id to the | 1=pod 2 3=head1 NAME 4 5SSL_CTX_set_session_cache_mode, SSL_CTX_get_session_cache_mode - enable/disable session caching 6 7=head1 SYNOPSIS 8 --- 12 unchanged lines hidden (view full) --- 21=head1 NOTES 22 23The OpenSSL library can store/retrieve SSL/TLS sessions for later reuse. 24The sessions can be held in memory for each B<ctx>, if more than one 25SSL_CTX object is being maintained, the sessions are unique for each SSL_CTX 26object. 27 28In order to reuse a session, a client must send the session's id to the |
| 29server. It can only send exactly one id. The server then decides whether it 30agrees in reusing the session or starts the handshake for a new session. | 29server. It can only send exactly one id. The server then either 30agrees to reuse the session or it starts a full handshake (to create a new 31session). |
| 31 | 32 |
| 32A server will lookup up the session in its internal session storage. If 33the session is not found in internal storage or internal storage is 34deactivated, the server will try the external storage if available. | 33A server will lookup up the session in its internal session storage. If the 34session is not found in internal storage or lookups for the internal storage 35have been deactivated (SSL_SESS_CACHE_NO_INTERNAL_LOOKUP), the server will try 36the external storage if available. |
| 35 36Since a client may try to reuse a session intended for use in a different 37context, the session id context must be set by the server (see 38L<SSL_CTX_set_session_id_context(3)|SSL_CTX_set_session_id_context(3)>). 39 40The following session cache modes and modifiers are available: 41 42=over 4 --- 9 unchanged lines hidden (view full) --- 52session to choose (due to the abstract BIO layer the SSL engine does not 53have details about the connection), the application must select the session 54to be reused by using the L<SSL_set_session(3)|SSL_set_session(3)> 55function. This option is not activated by default. 56 57=item SSL_SESS_CACHE_SERVER 58 59Server sessions are added to the session cache. When a client proposes a | 37 38Since a client may try to reuse a session intended for use in a different 39context, the session id context must be set by the server (see 40L<SSL_CTX_set_session_id_context(3)|SSL_CTX_set_session_id_context(3)>). 41 42The following session cache modes and modifiers are available: 43 44=over 4 --- 9 unchanged lines hidden (view full) --- 54session to choose (due to the abstract BIO layer the SSL engine does not 55have details about the connection), the application must select the session 56to be reused by using the L<SSL_set_session(3)|SSL_set_session(3)> 57function. This option is not activated by default. 58 59=item SSL_SESS_CACHE_SERVER 60 61Server sessions are added to the session cache. When a client proposes a |
| 60session to be reused, the session is looked up in the internal session cache. 61If the session is found, the server will try to reuse the session. 62This is the default. | 62session to be reused, the server looks for the corresponding session in (first) 63the internal session cache (unless SSL_SESS_CACHE_NO_INTERNAL_LOOKUP is set), 64then (second) in the external cache if available. If the session is found, the 65server will try to reuse the session. This is the default. |
| 63 64=item SSL_SESS_CACHE_BOTH 65 66Enable both SSL_SESS_CACHE_CLIENT and SSL_SESS_CACHE_SERVER at the same time. 67 68=item SSL_SESS_CACHE_NO_AUTO_CLEAR 69 70Normally the session cache is checked for expired sessions every 71255 connections using the 72L<SSL_CTX_flush_sessions(3)|SSL_CTX_flush_sessions(3)> function. Since 73this may lead to a delay which cannot be controlled, the automatic 74flushing may be disabled and 75L<SSL_CTX_flush_sessions(3)|SSL_CTX_flush_sessions(3)> can be called 76explicitly by the application. 77 78=item SSL_SESS_CACHE_NO_INTERNAL_LOOKUP 79 | 66 67=item SSL_SESS_CACHE_BOTH 68 69Enable both SSL_SESS_CACHE_CLIENT and SSL_SESS_CACHE_SERVER at the same time. 70 71=item SSL_SESS_CACHE_NO_AUTO_CLEAR 72 73Normally the session cache is checked for expired sessions every 74255 connections using the 75L<SSL_CTX_flush_sessions(3)|SSL_CTX_flush_sessions(3)> function. Since 76this may lead to a delay which cannot be controlled, the automatic 77flushing may be disabled and 78L<SSL_CTX_flush_sessions(3)|SSL_CTX_flush_sessions(3)> can be called 79explicitly by the application. 80 81=item SSL_SESS_CACHE_NO_INTERNAL_LOOKUP 82 |
| 80By setting this flag sessions are cached in the internal storage but 81they are not looked up automatically. If an external session cache 82is enabled, sessions are looked up in the external cache. As automatic 83lookup only applies for SSL/TLS servers, the flag has no effect on | 83By setting this flag, session-resume operations in an SSL/TLS server will not 84automatically look up sessions in the internal cache, even if sessions are 85automatically stored there. If external session caching callbacks are in use, 86this flag guarantees that all lookups are directed to the external cache. 87As automatic lookup only applies for SSL/TLS servers, the flag has no effect on |
| 84clients. 85 | 88clients. 89 |
| 90=item SSL_SESS_CACHE_NO_INTERNAL_STORE 91 92Depending on the presence of SSL_SESS_CACHE_CLIENT and/or SSL_SESS_CACHE_SERVER, 93sessions negotiated in an SSL/TLS handshake may be cached for possible reuse. 94Normally a new session is added to the internal cache as well as any external 95session caching (callback) that is configured for the SSL_CTX. This flag will 96prevent sessions being stored in the internal cache (though the application can 97add them manually using L<SSL_CTX_add_session(3)|SSL_CTX_add_session(3)>). Note: 98in any SSL/TLS servers where external caching is configured, any successful 99session lookups in the external cache (ie. for session-resume requests) would 100normally be copied into the local cache before processing continues - this flag 101prevents these additions to the internal cache as well. 102 103=item SSL_SESS_CACHE_NO_INTERNAL 104 105Enable both SSL_SESS_CACHE_NO_INTERNAL_LOOKUP and 106SSL_SESS_CACHE_NO_INTERNAL_STORE at the same time. 107 108 |
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| 86=back 87 88The default mode is SSL_SESS_CACHE_SERVER. 89 90=head1 RETURN VALUES 91 92SSL_CTX_set_session_cache_mode() returns the previously set cache mode. 93 94SSL_CTX_get_session_cache_mode() returns the currently set cache mode. 95 96 97=head1 SEE ALSO 98 99L<ssl(3)|ssl(3)>, L<SSL_set_session(3)|SSL_set_session(3)>, 100L<SSL_session_reused(3)|SSL_session_reused(3)>, | 109=back 110 111The default mode is SSL_SESS_CACHE_SERVER. 112 113=head1 RETURN VALUES 114 115SSL_CTX_set_session_cache_mode() returns the previously set cache mode. 116 117SSL_CTX_get_session_cache_mode() returns the currently set cache mode. 118 119 120=head1 SEE ALSO 121 122L<ssl(3)|ssl(3)>, L<SSL_set_session(3)|SSL_set_session(3)>, 123L<SSL_session_reused(3)|SSL_session_reused(3)>, |
| 124L<SSL_CTX_add_session(3)|SSL_CTX_add_session(3)>, |
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| 101L<SSL_CTX_sess_number(3)|SSL_CTX_sess_number(3)>, 102L<SSL_CTX_sess_set_cache_size(3)|SSL_CTX_sess_set_cache_size(3)>, 103L<SSL_CTX_sess_set_get_cb(3)|SSL_CTX_sess_set_get_cb(3)>, 104L<SSL_CTX_set_session_id_context(3)|SSL_CTX_set_session_id_context(3)>, 105L<SSL_CTX_set_timeout(3)|SSL_CTX_set_timeout(3)>, 106L<SSL_CTX_flush_sessions(3)|SSL_CTX_flush_sessions(3)> 107 | 125L<SSL_CTX_sess_number(3)|SSL_CTX_sess_number(3)>, 126L<SSL_CTX_sess_set_cache_size(3)|SSL_CTX_sess_set_cache_size(3)>, 127L<SSL_CTX_sess_set_get_cb(3)|SSL_CTX_sess_set_get_cb(3)>, 128L<SSL_CTX_set_session_id_context(3)|SSL_CTX_set_session_id_context(3)>, 129L<SSL_CTX_set_timeout(3)|SSL_CTX_set_timeout(3)>, 130L<SSL_CTX_flush_sessions(3)|SSL_CTX_flush_sessions(3)> 131 |
| 132=head1 HISTORY 133 134SSL_SESS_CACHE_NO_INTERNAL_STORE and SSL_SESS_CACHE_NO_INTERNAL 135were introduced in OpenSSL 0.9.6h. 136 |
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| 108=cut | 137=cut |