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Diffstat (limited to 'secure/lib/libcrypto/man/SSL_read.3')
| -rw-r--r-- | secure/lib/libcrypto/man/SSL_read.3 | 244 |
1 files changed, 244 insertions, 0 deletions
diff --git a/secure/lib/libcrypto/man/SSL_read.3 b/secure/lib/libcrypto/man/SSL_read.3 new file mode 100644 index 0000000..b3d6489 --- /dev/null +++ b/secure/lib/libcrypto/man/SSL_read.3 @@ -0,0 +1,244 @@ +.\" Automatically generated by Pod::Man version 1.15 +.\" Thu May 9 13:21:32 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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If the +peer requests a re-negotiation, it will be performed transparently during +the \fISSL_read()\fR operation. The behaviour of \fISSL_read()\fR depends on the +underlying \s-1BIO\s0. +.PP +For the transparent negotiation to succeed, the \fBssl\fR must have been +initialized to client or server mode. This is being done by calling +SSL_set_connect_state(3) or \fISSL_set_accept_state()\fR +before the first call to an \fISSL_read()\fR or SSL_write(3) +function. +.PP +\&\fISSL_read()\fR works based on the \s-1SSL/TLS\s0 records. The data are received in +records (with a maximum record size of 16kB for SSLv3/TLSv1). Only when a +record has been completely received, it can be processed (decryption and +check of integrity). Therefore data that was not retrieved at the last +call of \fISSL_read()\fR can still be buffered inside the \s-1SSL\s0 layer and will be +retrieved on the next call to \fISSL_read()\fR. If \fBnum\fR is higher than the +number of bytes buffered, \fISSL_read()\fR will return with the bytes buffered. +If no more bytes are in the buffer, \fISSL_read()\fR will trigger the processing +of the next record. Only when the record has been received and processed +completely, \fISSL_read()\fR will return reporting success. At most the contents +of the record will be returned. As the size of an \s-1SSL/TLS\s0 record may exceed +the maximum packet size of the underlying transport (e.g. \s-1TCP\s0), it may +be necessary to read several packets from the transport layer before the +record is complete and \fISSL_read()\fR can succeed. +.PP +If the underlying \s-1BIO\s0 is \fBblocking\fR, \fISSL_read()\fR will only return, once the +read operation has been finished or an error occurred, except when a +renegotiation take place, in which case a \s-1SSL_ERROR_WANT_READ\s0 may occur. +This behaviour can be controlled with the \s-1SSL_MODE_AUTO_RETRY\s0 flag of the +SSL_CTX_set_mode(3) call. +.PP +If the underlying \s-1BIO\s0 is \fBnon-blocking\fR, \fISSL_read()\fR will also return +when the underlying \s-1BIO\s0 could not satisfy the needs of \fISSL_read()\fR +to continue the operation. In this case a call to +SSL_get_error(3) with the +return value of \fISSL_read()\fR will yield \fB\s-1SSL_ERROR_WANT_READ\s0\fR or +\&\fB\s-1SSL_ERROR_WANT_WRITE\s0\fR. As at any time a re-negotiation is possible, a +call to \fISSL_read()\fR can also cause write operations! The calling process +then must repeat the call after taking appropriate action to satisfy the +needs of \fISSL_read()\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. +.SH "WARNING" +.IX Header "WARNING" +When an \fISSL_read()\fR operation has to be repeated because of +\&\fB\s-1SSL_ERROR_WANT_READ\s0\fR or \fB\s-1SSL_ERROR_WANT_WRITE\s0\fR, it must be repeated +with the same arguments. +.SH "RETURN VALUES" +.IX Header "RETURN VALUES" +The following return values can occur: +.Ip ">0" 4 +.IX Item ">0" +The read operation was successful; the return value is the number of +bytes actually read from the \s-1TLS/SSL\s0 connection. +.Ip "0" 4 +The read operation was not successful. The reason may either be a clean +shutdown due to a \*(L"close notify\*(R" alert sent by the peer (in which case +the \s-1SSL_RECEIVED_SHUTDOWN\s0 flag in the ssl shutdown state is set +(see SSL_shutdown(3), +SSL_set_shutdown(3)). It is also possible, that +the peer simply shut down the underlying transport and the shutdown is +incomplete. Call \fISSL_get_error()\fR with the return value \fBret\fR to find out, +whether an error occurred or the connection was shut down cleanly +(\s-1SSL_ERROR_ZERO_RETURN\s0). +.Sp +SSLv2 (deprecated) does not support a shutdown alert protocol, so it can +only be detected, whether the underlying connection was closed. It cannot +be checked, whether the closure was initiated by the peer or by something +else. +.Ip "<0" 4 +.IX Item "<0" +The read operation was not successful, because either an error occurred +or action must be taken by the calling process. Call \fISSL_get_error()\fR with the +return value \fBret\fR to find out the reason. +.SH "SEE ALSO" +.IX Header "SEE ALSO" +SSL_get_error(3), SSL_write(3), +SSL_CTX_set_mode(3), SSL_CTX_new(3), +SSL_connect(3), SSL_accept(3) +SSL_set_connect_state(3), +SSL_shutdown(3), SSL_set_shutdown(3), +ssl(3), bio(3) |
