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.\" $OpenBSD: SSL_CTX_set_read_ahead.3,v 1.4 2018/03/27 17:35:50 schwarze Exp $
.\" OpenSSL b97fdb57 Nov 11 09:33:09 2016 +0100
.\"
.\" This file was written by Matt Caswell <matt@openssl.org>.
.\" Copyright (c) 2015, 2016 The OpenSSL Project. All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\"
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\"
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in
.\" the documentation and/or other materials provided with the
.\" distribution.
.\"
.\" 3. All advertising materials mentioning features or use of this
.\" software must display the following acknowledgment:
.\" "This product includes software developed by the OpenSSL Project
.\" for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
.\"
.\" 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
.\" endorse or promote products derived from this software without
.\" prior written permission. For written permission, please contact
.\" openssl-core@openssl.org.
.\"
.\" 5. Products derived from this software may not be called "OpenSSL"
.\" nor may "OpenSSL" appear in their names without prior written
.\" permission of the OpenSSL Project.
.\"
.\" 6. Redistributions of any form whatsoever must retain the following
.\" acknowledgment:
.\" "This product includes software developed by the OpenSSL Project
.\" for use in the OpenSSL Toolkit (http://www.openssl.org/)"
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
.\" EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
.\" ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
.\" SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
.\" STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
.\" OF THE POSSIBILITY OF SUCH DAMAGE.
.\"
.Dd $Mdocdate: March 27 2018 $
.Dt SSL_CTX_SET_READ_AHEAD 3
.Os
.Sh NAME
.Nm SSL_CTX_set_read_ahead ,
.Nm SSL_CTX_get_read_ahead ,
.Nm SSL_set_read_ahead ,
.Nm SSL_get_read_ahead ,
.Nm SSL_CTX_get_default_read_ahead
.Nd manage whether to read as many input bytes as possible
.Sh SYNOPSIS
.In openssl/ssl.h
.Ft void
.Fo SSL_CTX_set_read_ahead
.Fa "SSL_CTX *ctx"
.Fa "int yes"
.Fc
.Ft long
.Fo SSL_CTX_get_read_ahead
.Fa "SSL_CTX *ctx"
.Fc
.Ft void
.Fo SSL_set_read_ahead
.Fa "SSL *s"
.Fa "int yes"
.Fc
.Ft long
.Fo SSL_get_read_ahead
.Fa "const SSL *s"
.Fc
.Ft long
.Fo SSL_CTX_get_default_read_ahead
.Fa "SSL_CTX *ctx"
.Fc
.Sh DESCRIPTION
.Fn SSL_CTX_set_read_ahead
and
.Fn SSL_set_read_ahead
set whether as many input bytes as possible are read for non-blocking
reads.
For example if
.Ar x
bytes are currently required by OpenSSL, but
.Ar y
bytes are available from the underlying BIO (where
.Ar y No > Ar x ) ,
then OpenSSL will read all
.Ar y
bytes into its buffer (provided that the buffer is large enough) if
reading ahead is on, or
.Ar x
bytes otherwise.
The parameter
.Fa yes
should be 0 to ensure reading ahead is off, or non zero otherwise.
.Pp
.Fn SSL_CTX_get_read_ahead
and
.Fn SSL_get_read_ahead
indicate whether reading ahead is set or not.
.Pp
.Fn SSL_CTX_get_default_read_ahead
is identical to
.Fn SSL_CTX_get_read_ahead .
.Pp
These functions are implemented as macros.
.Pp
These functions have no effect when used with DTLS.
.Sh RETURN VALUES
.Fn SSL_CTX_get_read_ahead
and
.Fn SSL_get_read_ahead
return 0 if reading ahead is off or non-zero otherwise,
except that the return values are undefined for DTLS.
.Sh SEE ALSO
.Xr ssl 3 ,
.Xr SSL_pending 3
.Sh HISTORY
.Fn SSL_set_read_ahead
and
.Fn SSL_get_read_ahead
appeared in SSLeay 0.4 or earlier and have been available since
.Ox 2.4 .
.Pp
.Fn SSL_CTX_set_read_ahead ,
.Fn SSL_CTX_get_read_ahead ,
and
.Fn SSL_CTX_get_default_read_ahead
first appeared in OpenSSL 0.9.2b and have been available since
.Ox 2.6 .
.Sh CAVEATS
Switching read ahead on can impact the behaviour of the
.Xr SSL_pending 3
function.
|
