From 5dadf34209c288b8fffba1016e6a3c9446381153 Mon Sep 17 00:00:00 2001 From: Rob Austein Date: Thu, 7 Jun 2007 02:37:32 +0000 Subject: Replace hacked OpenSSL code with OpenSSL 0.9.8e distribution. svn path=/openssl/Makefile; revision=659 --- openssl/trunk/doc/ssl/SSL_shutdown.pod | 125 --------------------------------- 1 file changed, 125 deletions(-) delete mode 100644 openssl/trunk/doc/ssl/SSL_shutdown.pod (limited to 'openssl/trunk/doc/ssl/SSL_shutdown.pod') diff --git a/openssl/trunk/doc/ssl/SSL_shutdown.pod b/openssl/trunk/doc/ssl/SSL_shutdown.pod deleted file mode 100644 index 89911acb..00000000 --- a/openssl/trunk/doc/ssl/SSL_shutdown.pod +++ /dev/null @@ -1,125 +0,0 @@ -=pod - -=head1 NAME - -SSL_shutdown - shut down a TLS/SSL connection - -=head1 SYNOPSIS - - #include - - 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 shutdown procedure consists of 2 steps: the sending of the "close notify" -shutdown alert and the reception of the peer's "close notify" shutdown -alert. According to the TLS standard, it is acceptable for an application -to only send its shutdown alert and then close the underlying connection -without waiting for the peer's response (this way resources can be saved, -as the process can already terminate or serve another connection). -When the underlying connection shall be used for more communications, the -complete shutdown procedure (bidirectional "close notify" alerts) must be -performed, so that the peers stay synchronized. - -SSL_shutdown() supports both uni- and bidirectional shutdown by its 2 step -behaviour. - -=over 4 - -=item When the application is the first party to send the "close notify" -alert, SSL_shutdown() will only send the alert and then set the -SSL_SENT_SHUTDOWN flag (so that the session is considered good and will -be kept in cache). SSL_shutdown() will then return with 0. If a unidirectional -shutdown is enough (the underlying connection shall be closed anyway), this -first call to SSL_shutdown() is sufficient. In order to complete the -bidirectional shutdown handshake, SSL_shutdown() must be called again. -The second call will make SSL_shutdown() wait for the peer's "close notify" -shutdown alert. On success, the second call to SSL_shutdown() will return -with 1. - -=item If the peer already sent the "close notify" alert B it was -already processed implicitly inside another function -(L), the SSL_RECEIVED_SHUTDOWN flag is set. -SSL_shutdown() will send the "close notify" alert, set the SSL_SENT_SHUTDOWN -flag and will immediately return with 1. -Whether SSL_RECEIVED_SHUTDOWN is already set can be checked using the -SSL_get_shutdown() (see also L call. - -=back - -It is therefore recommended, to check the return value of SSL_shutdown() -and call SSL_shutdown() again, if the bidirectional shutdown is not yet -complete (return value of the first call is 0). As the shutdown is not -specially handled in the SSLv2 protocol, SSL_shutdown() will succeed on -the first call. - -The behaviour of SSL_shutdown() additionally depends on the underlying BIO. - -If the underlying BIO is B, SSL_shutdown() will only return once the -handshake step has been finished or an error occurred. - -If the underlying BIO is B, 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 or -B. 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. - -SSL_shutdown() can be modified to only set the connection to "shutdown" -state but not actually send the "close notify" alert messages, -see L. -When "quiet shutdown" is enabled, SSL_shutdown() will always succeed -and return 1. - -=head1 RETURN VALUES - -The following return values can occur: - -=over 4 - -=item 1 - -The shutdown was successfully completed. The "close notify" alert was sent -and the peer's "close notify" alert was received. - -=item 0 - -The shutdown is not yet finished. Call SSL_shutdown() for a second time, -if a bidirectional shutdown shall be performed. -The output of L may be misleading, as an -erroneous SSL_ERROR_SYSCALL may be flagged even though no error occurred. - -=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 if -action is need to continue the operation for non-blocking BIOs. -Call L with the return value B -to find out the reason. - -=back - -=head1 SEE ALSO - -L, L, -L, L, -L, -L, L, -L, L - -=cut -- cgit v1.2.3