73 lines
2.2 KiB
Plaintext
73 lines
2.2 KiB
Plaintext
=pod
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=head1 NAME
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SSL_shutdown - shut down a TLS/SSL connection
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=head1 SYNOPSIS
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#include <openssl/ssl.h>
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int SSL_shutdown(SSL *ssl);
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=head1 DESCRIPTION
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SSL_shutdown() shuts down an active TLS/SSL connection. It sends the
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"close notify" shutdown alert to the peer.
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=head1 NOTES
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SSL_shutdown() tries to send the "close notify" shutdown alert to the peer.
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Whether the operation succeeds or not, the SSL_SENT_SHUTDOWN flag is set and
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a currently open session is considered closed and good and will be kept in the
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session cache for further reuse.
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The behaviour of SSL_shutdown() depends on the underlying BIO.
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If the underlying BIO is B<blocking>, SSL_shutdown() will only return once the
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handshake has been finished or an error occurred.
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If the underlying BIO is B<non-blocking>, SSL_shutdown() will also return
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when the underlying BIO could not satisfy the needs of SSL_shutdown()
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to continue the handshake. In this case a call to SSL_get_error() with the
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return value of SSL_shutdown() will yield B<SSL_ERROR_WANT_READ> or
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B<SSL_ERROR_WANT_WRITE>. The calling process then must repeat the call after
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taking appropriate action to satisfy the needs of SSL_shutdown().
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The action depends on the underlying BIO. When using a non-blocking socket,
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nothing is to be done, but select() can be used to check for the required
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condition. When using a buffering BIO, like a BIO pair, data must be written
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into or retrieved out of the BIO before being able to continue.
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=head1 RETURN VALUES
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The following return values can occur:
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=over 4
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=item 1
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The shutdown was successfully completed.
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=item 0
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The shutdown was not successful. Call SSL_get_error() with the return
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value B<ret> to find out the reason.
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=item -1
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The shutdown was not successful because a fatal error occurred either
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at the protocol level or a connection failure occurred. It can also occur of
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action is need to continue the operation for non-blocking BIOs.
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Call SSL_get_error() with the return value B<ret> to find out the reason.
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=back
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=head1 SEE ALSO
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L<SSL_get_error(3)|SSL_get_error(3)>, L<SSL_connect(3)|SSL_connect(3)>,
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L<SSL_accept(3)|SSL_accept(3)>, L<SSL_set_shutdown(3)|SSL_set_shutdown(3)>,
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L<SSL_clear(3)|SSL_clear(3), L<SSL_free(3)|SSL_free(3)>,
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L<ssl(3)|ssl(3)>, L<bio(3)|bio(3)>
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=cut
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