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Diffstat (limited to 'secure/lib/libcrypto/man/SSL_shutdown.3')
| -rw-r--r-- | secure/lib/libcrypto/man/SSL_shutdown.3 | 237 |
1 files changed, 0 insertions, 237 deletions
diff --git a/secure/lib/libcrypto/man/SSL_shutdown.3 b/secure/lib/libcrypto/man/SSL_shutdown.3 deleted file mode 100644 index 7dbc29e..0000000 --- a/secure/lib/libcrypto/man/SSL_shutdown.3 +++ /dev/null @@ -1,237 +0,0 @@ -.\" Automatically generated by Pod::Man version 1.15 -.\" Tue Jul 30 09:22:55 2002 -.\" -.\" Standard preamble: -.\" ====================================================================== -.de Sh \" Subsection heading -.br -.if t .Sp -.ne 5 -.PP -\fB\\$1\fR -.PP -.. -.de Sp \" Vertical space (when we can't use .PP) -.if t .sp .5v -.if n .sp -.. -.de Ip \" List item -.br -.ie \\n(.$>=3 .ne \\$3 -.el .ne 3 -.IP "\\$1" \\$2 -.. -.de Vb \" Begin verbatim text -.ft CW -.nf -.ne \\$1 -.. -.de Ve \" End verbatim text -.ft R - -.fi -.. -.\" Set up some character translations and predefined strings. \*(-- will -.\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left -.\" double quote, and \*(R" will give a right double quote. | will give a -.\" real vertical bar. \*(C+ will give a nicer C++. Capital omega is used -.\" to do unbreakable dashes and therefore won't be available. \*(C` and -.\" \*(C' expand to `' in nroff, nothing in troff, for use with C<> -.tr \(*W-|\(bv\*(Tr -.ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p' -.ie n \{\ -. ds -- \(*W- -. ds PI pi -. if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch -. if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch -. ds L" "" -. ds R" "" -. ds C` "" -. ds C' "" -'br\} -.el\{\ -. ds -- \|\(em\| -. ds PI \(*p -. ds L" `` -. ds R" '' -'br\} -.\" -.\" If the F register is turned on, we'll generate index entries on stderr -.\" for titles (.TH), headers (.SH), subsections (.Sh), items (.Ip), and -.\" index entries marked with X<> in POD. Of course, you'll have to process -.\" the output yourself in some meaningful fashion. -.if \nF \{\ -. de IX -. tm Index:\\$1\t\\n%\t"\\$2" -.. -. nr % 0 -. rr F -.\} -.\" -.\" For nroff, turn off justification. Always turn off hyphenation; it -.\" makes way too many mistakes in technical documents. -.hy 0 -.if n .na -.\" -.\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2). -.\" Fear. Run. Save yourself. 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It sends the -\&\*(L"close notify\*(R" shutdown alert to the peer. -.SH "NOTES" -.IX Header "NOTES" -\&\fISSL_shutdown()\fR tries to send the \*(L"close notify\*(R" shutdown alert to the peer. -Whether the operation succeeds or not, the \s-1SSL_SENT_SHUTDOWN\s0 flag is set and -a currently open session is considered closed and good and will be kept in the -session cache for further reuse. -.PP -The shutdown procedure consists of 2 steps: the sending of the \*(L"close notify\*(R" -shutdown alert and the reception of the peer's \*(L"close notify\*(R" shutdown -alert. According to the \s-1TLS\s0 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 \*(L"close notify\*(R" alerts) must be -performed, so that the peers stay synchronized. -.PP -\&\fISSL_shutdown()\fR supports both uni- and bidirectional shutdown by its 2 step -behaviour. -.if n .Ip "When the application is the first party to send the """"close notify"""" alert, \fISSL_shutdown()\fR will only send the alert and the set the \s-1SSL_SENT_SHUTDOWN\s0 flag (so that the session is considered good and will be kept in cache). \fISSL_shutdown()\fR will then return with 0. If a unidirectional shutdown is enough (the underlying connection shall be closed anyway), this first call to \fISSL_shutdown()\fR is sufficient. In order to complete the bidirectional shutdown handshake, \fISSL_shutdown()\fR must be called again. The second call will make \fISSL_shutdown()\fR wait for the peer's """"close notify"""" shutdown alert. On success, the second call to \fISSL_shutdown()\fR will return with 1." 4 -.el .Ip "When the application is the first party to send the ``close notify'' alert, \fISSL_shutdown()\fR will only send the alert and the set the \s-1SSL_SENT_SHUTDOWN\s0 flag (so that the session is considered good and will be kept in cache). \fISSL_shutdown()\fR will then return with 0. If a unidirectional shutdown is enough (the underlying connection shall be closed anyway), this first call to \fISSL_shutdown()\fR is sufficient. In order to complete the bidirectional shutdown handshake, \fISSL_shutdown()\fR must be called again. The second call will make \fISSL_shutdown()\fR wait for the peer's ``close notify'' shutdown alert. On success, the second call to \fISSL_shutdown()\fR will return with 1." 4 -.IX Item "When the application is the first party to send the "close notify alert, SSL_shutdown() will only send the alert and the 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." -.PD 0 -.if n .Ip "If the peer already sent the """"close notify"""" alert \fBand\fR it was already processed implicitly inside another function (SSL_read(3)), the \s-1SSL_RECEIVED_SHUTDOWN\s0 flag is set. \fISSL_shutdown()\fR will send the """"close notify"""" alert, set the \s-1SSL_SENT_SHUTDOWN\s0 flag and will immediately return with 1. Whether \s-1SSL_RECEIVED_SHUTDOWN\s0 is already set can be checked using the \fISSL_get_shutdown()\fR (see also SSL_set_shutdown(3) call." 4 -.el .Ip "If the peer already sent the ``close notify'' alert \fBand\fR it was already processed implicitly inside another function (SSL_read(3)), the \s-1SSL_RECEIVED_SHUTDOWN\s0 flag is set. \fISSL_shutdown()\fR will send the ``close notify'' alert, set the \s-1SSL_SENT_SHUTDOWN\s0 flag and will immediately return with 1. Whether \s-1SSL_RECEIVED_SHUTDOWN\s0 is already set can be checked using the \fISSL_get_shutdown()\fR (see also SSL_set_shutdown(3) call." 4 -.IX Item "If the peer already sent the "close notify alert and it was already processed implicitly inside another function (SSL_read(3)), 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 SSL_set_shutdown(3) call." -.PD -.PP -It is therefore recommended, to check the return value of \fISSL_shutdown()\fR -and call \fISSL_shutdown()\fR 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, \fISSL_shutdown()\fR will succeed on -the first call. -.PP -The behaviour of \fISSL_shutdown()\fR additionally depends on the underlying \s-1BIO\s0. -.PP -If the underlying \s-1BIO\s0 is \fBblocking\fR, \fISSL_shutdown()\fR will only return once the -handshake step has been finished or an error occurred. -.PP -If the underlying \s-1BIO\s0 is \fBnon-blocking\fR, \fISSL_shutdown()\fR will also return -when the underlying \s-1BIO\s0 could not satisfy the needs of \fISSL_shutdown()\fR -to continue the handshake. In this case a call to \fISSL_get_error()\fR with the -return value of \fISSL_shutdown()\fR will yield \fB\s-1SSL_ERROR_WANT_READ\s0\fR or -\&\fB\s-1SSL_ERROR_WANT_WRITE\s0\fR. The calling process then must repeat the call after -taking appropriate action to satisfy the needs of \fISSL_shutdown()\fR. -The action depends on the underlying \s-1BIO\s0. When using a non-blocking socket, -nothing is to be done, but \fIselect()\fR can be used to check for the required -condition. When using a buffering \s-1BIO\s0, like a \s-1BIO\s0 pair, data must be written -into or retrieved out of the \s-1BIO\s0 before being able to continue. -.PP -\&\fISSL_shutdown()\fR can be modified to only set the connection to \*(L"shutdown\*(R" -state but not actually send the \*(L"close notify\*(R" alert messages, -see SSL_CTX_set_quiet_shutdown(3). -When \*(L"quiet shutdown\*(R" is enabled, \fISSL_shutdown()\fR will always succeed -and return 1. -.SH "RETURN VALUES" -.IX Header "RETURN VALUES" -The following return values can occur: -.Ip "1" 4 -.IX Item "1" -The shutdown was successfully completed. The \*(L"close notify\*(R" alert was sent -and the peer's \*(L"close notify\*(R" alert was received. -.Ip "0" 4 -The shutdown is not yet finished. Call \fISSL_shutdown()\fR for a second time, -if a bidirectional shutdown shall be performed. -The output of SSL_get_error(3) may be misleading, as an -erroneous \s-1SSL_ERROR_SYSCALL\s0 may be flagged even though no error occurred. -.Ip "\-1" 4 -.IX 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 SSL_get_error(3) with the return value \fBret\fR -to find out the reason. -.SH "SEE ALSO" -.IX Header "SEE ALSO" -SSL_get_error(3), SSL_connect(3), -SSL_accept(3), SSL_set_shutdown(3), -SSL_CTX_set_quiet_shutdown(3), -SSL_clear(3), SSL_free(3), -ssl(3), bio(3) |
