diff options
Diffstat (limited to 'secure/lib/libcrypto/man/BIO_s_bio.3')
| -rw-r--r-- | secure/lib/libcrypto/man/BIO_s_bio.3 | 305 |
1 files changed, 305 insertions, 0 deletions
diff --git a/secure/lib/libcrypto/man/BIO_s_bio.3 b/secure/lib/libcrypto/man/BIO_s_bio.3 new file mode 100644 index 0000000..afd3307 --- /dev/null +++ b/secure/lib/libcrypto/man/BIO_s_bio.3 @@ -0,0 +1,305 @@ +.\" Automatically generated by Pod::Man 2.22 (Pod::Simple 3.07) +.\" +.\" Standard preamble: +.\" ======================================================================== +.de Sp \" Vertical space (when we can't use .PP) +.if t .sp .5v +.if n .sp +.. +.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. \*(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- +.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\} +.\" +.\" Escape single quotes in literal strings from groff's Unicode transform. +.ie \n(.g .ds Aq \(aq +.el .ds Aq ' +.\" +.\" If the F register is turned on, we'll generate index entries on stderr for +.\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index +.\" entries marked with X<> in POD. Of course, you'll have to process the +.\" output yourself in some meaningful fashion. +.ie \nF \{\ +. de IX +. tm Index:\\$1\t\\n%\t"\\$2" +.. +. nr % 0 +. rr F +.\} +.el \{\ +. de IX +.. +.\} +.\" +.\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2). +.\" Fear. Run. Save yourself. No user-serviceable parts. +. \" fudge factors for nroff and troff +.if n \{\ +. ds #H 0 +. ds #V .8m +. ds #F .3m +. ds #[ \f1 +. ds #] \fP +.\} +.if t \{\ +. ds #H ((1u-(\\\\n(.fu%2u))*.13m) +. ds #V .6m +. ds #F 0 +. ds #[ \& +. ds #] \& +.\} +. \" simple accents for nroff and troff +.if n \{\ +. ds ' \& +. ds ` \& +. ds ^ \& +. ds , \& +. ds ~ ~ +. ds / +.\} +.if t \{\ +. ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u" +. ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u' +. ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u' +. ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u' +. ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u' +. ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u' +.\} +. \" troff and (daisy-wheel) nroff accents +.ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V' +.ds 8 \h'\*(#H'\(*b\h'-\*(#H' +.ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#] +.ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H' +.ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u' +.ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#] +.ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#] +.ds ae a\h'-(\w'a'u*4/10)'e +.ds Ae A\h'-(\w'A'u*4/10)'E +. \" corrections for vroff +.if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u' +.if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u' +. \" for low resolution devices (crt and lpr) +.if \n(.H>23 .if \n(.V>19 \ +\{\ +. ds : e +. ds 8 ss +. ds o a +. ds d- d\h'-1'\(ga +. ds D- D\h'-1'\(hy +. ds th \o'bp' +. ds Th \o'LP' +. ds ae ae +. ds Ae AE +.\} +.rm #[ #] #H #V #F C +.\" ======================================================================== +.\" +.IX Title "BIO_s_bio 3" +.TH BIO_s_bio 3 "2010-11-16" "0.9.8p" "OpenSSL" +.\" For nroff, turn off justification. Always turn off hyphenation; it makes +.\" way too many mistakes in technical documents. +.if n .ad l +.nh +.SH "NAME" +BIO_s_bio, BIO_make_bio_pair, BIO_destroy_bio_pair, BIO_shutdown_wr, +BIO_set_write_buf_size, BIO_get_write_buf_size, BIO_new_bio_pair, +BIO_get_write_guarantee, BIO_ctrl_get_write_guarantee, BIO_get_read_request, +BIO_ctrl_get_read_request, BIO_ctrl_reset_read_request \- BIO pair BIO +.SH "SYNOPSIS" +.IX Header "SYNOPSIS" +.Vb 1 +\& #include <openssl/bio.h> +\& +\& BIO_METHOD *BIO_s_bio(void); +\& +\& #define BIO_make_bio_pair(b1,b2) (int)BIO_ctrl(b1,BIO_C_MAKE_BIO_PAIR,0,b2) +\& #define BIO_destroy_bio_pair(b) (int)BIO_ctrl(b,BIO_C_DESTROY_BIO_PAIR,0,NULL) +\& +\& #define BIO_shutdown_wr(b) (int)BIO_ctrl(b, BIO_C_SHUTDOWN_WR, 0, NULL) +\& +\& #define BIO_set_write_buf_size(b,size) (int)BIO_ctrl(b,BIO_C_SET_WRITE_BUF_SIZE,size,NULL) +\& #define BIO_get_write_buf_size(b,size) (size_t)BIO_ctrl(b,BIO_C_GET_WRITE_BUF_SIZE,size,NULL) +\& +\& int BIO_new_bio_pair(BIO **bio1, size_t writebuf1, BIO **bio2, size_t writebuf2); +\& +\& #define BIO_get_write_guarantee(b) (int)BIO_ctrl(b,BIO_C_GET_WRITE_GUARANTEE,0,NULL) +\& size_t BIO_ctrl_get_write_guarantee(BIO *b); +\& +\& #define BIO_get_read_request(b) (int)BIO_ctrl(b,BIO_C_GET_READ_REQUEST,0,NULL) +\& size_t BIO_ctrl_get_read_request(BIO *b); +\& +\& int BIO_ctrl_reset_read_request(BIO *b); +.Ve +.SH "DESCRIPTION" +.IX Header "DESCRIPTION" +\&\fIBIO_s_bio()\fR returns the method for a \s-1BIO\s0 pair. A \s-1BIO\s0 pair is a pair of source/sink +BIOs where data written to either half of the pair is buffered and can be read from +the other half. Both halves must usually by handled by the same application thread +since no locking is done on the internal data structures. +.PP +Since \s-1BIO\s0 chains typically end in a source/sink \s-1BIO\s0 it is possible to make this +one half of a \s-1BIO\s0 pair and have all the data processed by the chain under application +control. +.PP +One typical use of \s-1BIO\s0 pairs is to place \s-1TLS/SSL\s0 I/O under application control, this +can be used when the application wishes to use a non standard transport for +\&\s-1TLS/SSL\s0 or the normal socket routines are inappropriate. +.PP +Calls to \fIBIO_read()\fR will read data from the buffer or request a retry if no +data is available. +.PP +Calls to \fIBIO_write()\fR will place data in the buffer or request a retry if the +buffer is full. +.PP +The standard calls \fIBIO_ctrl_pending()\fR and \fIBIO_ctrl_wpending()\fR can be used to +determine the amount of pending data in the read or write buffer. +.PP +\&\fIBIO_reset()\fR clears any data in the write buffer. +.PP +\&\fIBIO_make_bio_pair()\fR joins two separate BIOs into a connected pair. +.PP +\&\fIBIO_destroy_pair()\fR destroys the association between two connected BIOs. Freeing +up any half of the pair will automatically destroy the association. +.PP +\&\fIBIO_shutdown_wr()\fR is used to close down a \s-1BIO\s0 \fBb\fR. After this call no further +writes on \s-1BIO\s0 \fBb\fR are allowed (they will return an error). Reads on the other +half of the pair will return any pending data or \s-1EOF\s0 when all pending data has +been read. +.PP +\&\fIBIO_set_write_buf_size()\fR sets the write buffer size of \s-1BIO\s0 \fBb\fR to \fBsize\fR. +If the size is not initialized a default value is used. This is currently +17K, sufficient for a maximum size \s-1TLS\s0 record. +.PP +\&\fIBIO_get_write_buf_size()\fR returns the size of the write buffer. +.PP +\&\fIBIO_new_bio_pair()\fR combines the calls to \fIBIO_new()\fR, \fIBIO_make_bio_pair()\fR and +\&\fIBIO_set_write_buf_size()\fR to create a connected pair of BIOs \fBbio1\fR, \fBbio2\fR +with write buffer sizes \fBwritebuf1\fR and \fBwritebuf2\fR. If either size is +zero then the default size is used. \fIBIO_new_bio_pair()\fR does not check whether +\&\fBbio1\fR or \fBbio2\fR do point to some other \s-1BIO\s0, the values are overwritten, +\&\fIBIO_free()\fR is not called. +.PP +\&\fIBIO_get_write_guarantee()\fR and \fIBIO_ctrl_get_write_guarantee()\fR return the maximum +length of data that can be currently written to the \s-1BIO\s0. Writes larger than this +value will return a value from \fIBIO_write()\fR less than the amount requested or if the +buffer is full request a retry. \fIBIO_ctrl_get_write_guarantee()\fR is a function +whereas \fIBIO_get_write_guarantee()\fR is a macro. +.PP +\&\fIBIO_get_read_request()\fR and \fIBIO_ctrl_get_read_request()\fR return the +amount of data requested, or the buffer size if it is less, if the +last read attempt at the other half of the \s-1BIO\s0 pair failed due to an +empty buffer. This can be used to determine how much data should be +written to the \s-1BIO\s0 so the next read will succeed: this is most useful +in \s-1TLS/SSL\s0 applications where the amount of data read is usually +meaningful rather than just a buffer size. After a successful read +this call will return zero. It also will return zero once new data +has been written satisfying the read request or part of it. +Note that \fIBIO_get_read_request()\fR never returns an amount larger +than that returned by \fIBIO_get_write_guarantee()\fR. +.PP +\&\fIBIO_ctrl_reset_read_request()\fR can also be used to reset the value returned by +\&\fIBIO_get_read_request()\fR to zero. +.SH "NOTES" +.IX Header "NOTES" +Both halves of a \s-1BIO\s0 pair should be freed. That is even if one half is implicit +freed due to a \fIBIO_free_all()\fR or \fISSL_free()\fR call the other half needs to be freed. +.PP +When used in bidirectional applications (such as \s-1TLS/SSL\s0) care should be taken to +flush any data in the write buffer. This can be done by calling \fIBIO_pending()\fR +on the other half of the pair and, if any data is pending, reading it and sending +it to the underlying transport. This must be done before any normal processing +(such as calling \fIselect()\fR ) due to a request and \fIBIO_should_read()\fR being true. +.PP +To see why this is important consider a case where a request is sent using +\&\fIBIO_write()\fR and a response read with \fIBIO_read()\fR, this can occur during an +\&\s-1TLS/SSL\s0 handshake for example. \fIBIO_write()\fR will succeed and place data in the write +buffer. \fIBIO_read()\fR will initially fail and \fIBIO_should_read()\fR will be true. If +the application then waits for data to be available on the underlying transport +before flushing the write buffer it will never succeed because the request was +never sent! +.SH "RETURN VALUES" +.IX Header "RETURN VALUES" +\&\fIBIO_new_bio_pair()\fR returns 1 on success, with the new BIOs available in +\&\fBbio1\fR and \fBbio2\fR, or 0 on failure, with \s-1NULL\s0 pointers stored into the +locations for \fBbio1\fR and \fBbio2\fR. Check the error stack for more information. +.PP +[\s-1XXXXX:\s0 More return values need to be added here] +.SH "EXAMPLE" +.IX Header "EXAMPLE" +The \s-1BIO\s0 pair can be used to have full control over the network access of an +application. The application can call \fIselect()\fR on the socket as required +without having to go through the SSL-interface. +.PP +.Vb 6 +\& BIO *internal_bio, *network_bio; +\& ... +\& BIO_new_bio_pair(internal_bio, 0, network_bio, 0); +\& SSL_set_bio(ssl, internal_bio, internal_bio); +\& SSL_operations(); +\& ... +\& +\& application | TLS\-engine +\& | | +\& +\-\-\-\-\-\-\-\-\-\-> SSL_operations() +\& | /\e || +\& | || \e/ +\& | BIO\-pair (internal_bio) +\& +\-\-\-\-\-\-\-\-\-\-< BIO\-pair (network_bio) +\& | | +\& socket | +\& +\& ... +\& SSL_free(ssl); /* implicitly frees internal_bio */ +\& BIO_free(network_bio); +\& ... +.Ve +.PP +As the \s-1BIO\s0 pair will only buffer the data and never directly access the +connection, it behaves non-blocking and will return as soon as the write +buffer is full or the read buffer is drained. Then the application has to +flush the write buffer and/or fill the read buffer. +.PP +Use the \fIBIO_ctrl_pending()\fR, to find out whether data is buffered in the \s-1BIO\s0 +and must be transfered to the network. Use \fIBIO_ctrl_get_read_request()\fR to +find out, how many bytes must be written into the buffer before the +\&\fISSL_operation()\fR can successfully be continued. +.SH "WARNING" +.IX Header "WARNING" +As the data is buffered, \fISSL_operation()\fR may return with a \s-1ERROR_SSL_WANT_READ\s0 +condition, but there is still data in the write buffer. An application must +not rely on the error value of \fISSL_operation()\fR but must assure that the +write buffer is always flushed first. Otherwise a deadlock may occur as +the peer might be waiting for the data before being able to continue. +.SH "SEE ALSO" +.IX Header "SEE ALSO" +\&\fISSL_set_bio\fR\|(3), \fIssl\fR\|(3), \fIbio\fR\|(3), +\&\fIBIO_should_retry\fR\|(3), \fIBIO_read\fR\|(3) |
