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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-15 19:43:11 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-15 19:43:11 +0000 |
commit | fc22b3d6507c6745911b9dfcc68f1e665ae13dbc (patch) | |
tree | ce1e3bce06471410239a6f41282e328770aa404a /upstream/archlinux/man3/BIO_s_bio.3ssl | |
parent | Initial commit. (diff) | |
download | manpages-l10n-fc22b3d6507c6745911b9dfcc68f1e665ae13dbc.tar.xz manpages-l10n-fc22b3d6507c6745911b9dfcc68f1e665ae13dbc.zip |
Adding upstream version 4.22.0.upstream/4.22.0
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'upstream/archlinux/man3/BIO_s_bio.3ssl')
-rw-r--r-- | upstream/archlinux/man3/BIO_s_bio.3ssl | 254 |
1 files changed, 254 insertions, 0 deletions
diff --git a/upstream/archlinux/man3/BIO_s_bio.3ssl b/upstream/archlinux/man3/BIO_s_bio.3ssl new file mode 100644 index 00000000..31530acc --- /dev/null +++ b/upstream/archlinux/man3/BIO_s_bio.3ssl @@ -0,0 +1,254 @@ +.\" -*- mode: troff; coding: utf-8 -*- +.\" Automatically generated by Pod::Man 5.01 (Pod::Simple 3.43) +.\" +.\" 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 +.. +.\" \*(C` and \*(C' are quotes in nroff, nothing in troff, for use with C<>. +.ie n \{\ +. ds C` "" +. ds C' "" +'br\} +.el\{\ +. ds C` +. ds C' +'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 >0, 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. +.\" +.\" Avoid warning from groff about undefined register 'F'. +.de IX +.. +.nr rF 0 +.if \n(.g .if rF .nr rF 1 +.if (\n(rF:(\n(.g==0)) \{\ +. if \nF \{\ +. de IX +. tm Index:\\$1\t\\n%\t"\\$2" +.. +. if !\nF==2 \{\ +. nr % 0 +. nr F 2 +. \} +. \} +.\} +.rr rF +.\" ======================================================================== +.\" +.IX Title "BIO_S_BIO 3ssl" +.TH BIO_S_BIO 3ssl 2024-01-30 3.2.1 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> +\& +\& const BIO_METHOD *BIO_s_bio(void); +\& +\& int BIO_make_bio_pair(BIO *b1, BIO *b2); +\& int BIO_destroy_bio_pair(BIO *b); +\& int BIO_shutdown_wr(BIO *b); +\& +\& int BIO_set_write_buf_size(BIO *b, long size); +\& size_t BIO_get_write_buf_size(BIO *b, long size); +\& +\& int BIO_new_bio_pair(BIO **bio1, size_t writebuf1, BIO **bio2, size_t writebuf2); +\& +\& int BIO_get_write_guarantee(BIO *b); +\& size_t BIO_ctrl_get_write_guarantee(BIO *b); +\& int BIO_get_read_request(BIO *b); +\& size_t BIO_ctrl_get_read_request(BIO *b); +\& int BIO_ctrl_reset_read_request(BIO *b); +.Ve +.SH DESCRIPTION +.IX Header "DESCRIPTION" +\&\fBBIO_s_bio()\fR returns the method for a BIO pair. A BIO 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 BIO chains typically end in a source/sink BIO it is possible to make this +one half of a BIO pair and have all the data processed by the chain under application +control. +.PP +One typical use of BIO pairs is to place TLS/SSL I/O under application control, this +can be used when the application wishes to use a non standard transport for +TLS/SSL or the normal socket routines are inappropriate. +.PP +Calls to \fBBIO_read_ex()\fR will read data from the buffer or request a retry if no +data is available. +.PP +Calls to \fBBIO_write_ex()\fR will place data in the buffer or request a retry if the +buffer is full. +.PP +The standard calls \fBBIO_ctrl_pending()\fR and \fBBIO_ctrl_wpending()\fR can be used to +determine the amount of pending data in the read or write buffer. +.PP +\&\fBBIO_reset()\fR clears any data in the write buffer. +.PP +\&\fBBIO_make_bio_pair()\fR joins two separate BIOs into a connected pair. +.PP +\&\fBBIO_destroy_pair()\fR destroys the association between two connected BIOs. Freeing +up any half of the pair will automatically destroy the association. +.PP +\&\fBBIO_shutdown_wr()\fR is used to close down a BIO \fBb\fR. After this call no further +writes on BIO \fBb\fR are allowed (they will return an error). Reads on the other +half of the pair will return any pending data or EOF when all pending data has +been read. +.PP +\&\fBBIO_set_write_buf_size()\fR sets the write buffer size of BIO \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 TLS record. +.PP +\&\fBBIO_get_write_buf_size()\fR returns the size of the write buffer. +.PP +\&\fBBIO_new_bio_pair()\fR combines the calls to \fBBIO_new()\fR, \fBBIO_make_bio_pair()\fR and +\&\fBBIO_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. \fBBIO_new_bio_pair()\fR does not check whether +\&\fBbio1\fR or \fBbio2\fR do point to some other BIO, the values are overwritten, +\&\fBBIO_free()\fR is not called. +.PP +\&\fBBIO_get_write_guarantee()\fR and \fBBIO_ctrl_get_write_guarantee()\fR return the maximum +length of data that can be currently written to the BIO. Writes larger than this +value will return a value from \fBBIO_write_ex()\fR less than the amount requested or +if the buffer is full request a retry. \fBBIO_ctrl_get_write_guarantee()\fR is a +function whereas \fBBIO_get_write_guarantee()\fR is a macro. +.PP +\&\fBBIO_get_read_request()\fR and \fBBIO_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 BIO pair failed due to an +empty buffer. This can be used to determine how much data should be +written to the BIO so the next read will succeed: this is most useful +in TLS/SSL 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 \fBBIO_get_read_request()\fR never returns an amount larger +than that returned by \fBBIO_get_write_guarantee()\fR. +.PP +\&\fBBIO_ctrl_reset_read_request()\fR can also be used to reset the value returned by +\&\fBBIO_get_read_request()\fR to zero. +.SH NOTES +.IX Header "NOTES" +Both halves of a BIO pair should be freed. That is even if one half is implicit +freed due to a \fBBIO_free_all()\fR or \fBSSL_free()\fR call the other half needs to be freed. +.PP +When used in bidirectional applications (such as TLS/SSL) care should be taken to +flush any data in the write buffer. This can be done by calling \fBBIO_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 \fBselect()\fR ) due to a request and \fBBIO_should_read()\fR being true. +.PP +To see why this is important consider a case where a request is sent using +\&\fBBIO_write_ex()\fR and a response read with \fBBIO_read_ex()\fR, this can occur during an +TLS/SSL handshake for example. \fBBIO_write_ex()\fR will succeed and place data in the +write buffer. \fBBIO_read_ex()\fR will initially fail and \fBBIO_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! +.PP +\&\fBBIO_eof()\fR is true if no data is in the peer BIO and the peer BIO has been +shutdown. +.PP +\&\fBBIO_make_bio_pair()\fR, \fBBIO_destroy_bio_pair()\fR, \fBBIO_shutdown_wr()\fR, +\&\fBBIO_set_write_buf_size()\fR, \fBBIO_get_write_buf_size()\fR, +\&\fBBIO_get_write_guarantee()\fR, and \fBBIO_get_read_request()\fR are implemented +as macros. +.SH "RETURN VALUES" +.IX Header "RETURN VALUES" +\&\fBBIO_new_bio_pair()\fR returns 1 on success, with the new BIOs available in +\&\fBbio1\fR and \fBbio2\fR, or 0 on failure, with NULL pointers stored into the +locations for \fBbio1\fR and \fBbio2\fR. Check the error stack for more information. +.PP +[XXXXX: More return values need to be added here] +.SH EXAMPLES +.IX Header "EXAMPLES" +The BIO pair can be used to have full control over the network access of an +application. The application can call \fBselect()\fR on the socket as required +without having to go through the SSL-interface. +.PP +.Vb 1 +\& 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(); /* e.g. SSL_read and SSL_write */ +\& ... +\& +\& application | TLS\-engine +\& | | +\& +\-\-\-\-\-\-\-\-\-\-> SSL_operations() +\& | /\e || +\& | || \e/ +\& | BIO\-pair (internal_bio) +\& | BIO\-pair (network_bio) +\& | || /\e +\& | \e/ || +\& +\-\-\-\-\-\-\-\-\-\-\-< BIO_operations() +\& | | +\& | | +\& socket +\& +\& ... +\& SSL_free(ssl); /* implicitly frees internal_bio */ +\& BIO_free(network_bio); +\& ... +.Ve +.PP +As the BIO pair will only buffer the data and never directly access the +connection, it behaves nonblocking 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 \fBBIO_ctrl_pending()\fR, to find out whether data is buffered in the BIO +and must be transferred to the network. Use \fBBIO_ctrl_get_read_request()\fR to +find out, how many bytes must be written into the buffer before the +\&\fBSSL_operation()\fR can successfully be continued. +.SH WARNINGS +.IX Header "WARNINGS" +As the data is buffered, \fBSSL_operation()\fR may return with an ERROR_SSL_WANT_READ +condition, but there is still data in the write buffer. An application must +not rely on the error value of \fBSSL_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" +\&\fBSSL_set_bio\fR\|(3), \fBssl\fR\|(7), \fBbio\fR\|(7), +\&\fBBIO_should_retry\fR\|(3), \fBBIO_read_ex\fR\|(3) +.SH COPYRIGHT +.IX Header "COPYRIGHT" +Copyright 2000\-2020 The OpenSSL Project Authors. All Rights Reserved. +.PP +Licensed under the Apache License 2.0 (the "License"). You may not use +this file except in compliance with the License. You can obtain a copy +in the file LICENSE in the source distribution or at +<https://www.openssl.org/source/license.html>. |