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