4746f25ac6
[skip ci] Reviewed-by: Matt Caswell <matt@openssl.org> (Merged from https://github.com/openssl/openssl/pull/7829)
74 lines
2.6 KiB
Text
74 lines
2.6 KiB
Text
=pod
|
|
|
|
=head1 NAME
|
|
|
|
SSL_CTX_set_read_ahead, SSL_CTX_get_read_ahead,
|
|
SSL_set_read_ahead, SSL_get_read_ahead,
|
|
SSL_CTX_get_default_read_ahead
|
|
- manage whether to read as many input bytes as possible
|
|
|
|
=head1 SYNOPSIS
|
|
|
|
#include <openssl/ssl.h>
|
|
|
|
void SSL_set_read_ahead(SSL *s, int yes);
|
|
int SSL_get_read_ahead(const SSL *s);
|
|
|
|
SSL_CTX_set_read_ahead(SSL_CTX *ctx, int yes);
|
|
long SSL_CTX_get_read_ahead(SSL_CTX *ctx);
|
|
long SSL_CTX_get_default_read_ahead(SSL_CTX *ctx);
|
|
|
|
=head1 DESCRIPTION
|
|
|
|
SSL_CTX_set_read_ahead() and SSL_set_read_ahead() set whether we should read as
|
|
many input bytes as possible (for non-blocking reads) or not. For example if
|
|
B<x> bytes are currently required by OpenSSL, but B<y> bytes are available from
|
|
the underlying BIO (where B<y> > B<x>), then OpenSSL will read all B<y> bytes
|
|
into its buffer (providing that the buffer is large enough) if reading ahead is
|
|
on, or B<x> bytes otherwise.
|
|
Setting the parameter B<yes> to 0 turns reading ahead is off, other values turn
|
|
it on.
|
|
SSL_CTX_set_default_read_ahead() is identical to SSL_CTX_set_read_ahead().
|
|
|
|
SSL_CTX_get_read_ahead() and SSL_get_read_ahead() indicate whether reading
|
|
ahead has been set or not.
|
|
SSL_CTX_get_default_read_ahead() is identical to SSL_CTX_get_read_ahead().
|
|
|
|
=head1 NOTES
|
|
|
|
These functions have no impact when used with DTLS. The return values for
|
|
SSL_CTX_get_read_head() and SSL_get_read_ahead() are undefined for DTLS. Setting
|
|
B<read_ahead> can impact the behaviour of the SSL_pending() function
|
|
(see L<SSL_pending(3)>).
|
|
|
|
Since SSL_read() can return B<SSL_ERROR_WANT_READ> for non-application data
|
|
records, and SSL_has_pending() can't tell the difference between processed and
|
|
unprocessed data, it's recommended that if read ahead is turned on that
|
|
B<SSL_MODE_AUTO_RETRY> is not turned off using SSL_CTX_clear_mode().
|
|
That will prevent getting B<SSL_ERROR_WANT_READ> when there is still a complete
|
|
record availale that hasn't been processed.
|
|
|
|
If the application wants to continue to use the underlying transport (e.g. TCP
|
|
connection) after the SSL connection is finished using SSL_shutdown() reading
|
|
ahead should be turned off.
|
|
Otherwise the SSL structure might read data that it shouldn't.
|
|
|
|
=head1 RETURN VALUES
|
|
|
|
SSL_get_read_ahead() and SSL_CTX_get_read_ahead() return 0 if reading ahead is off,
|
|
and non zero otherwise.
|
|
|
|
=head1 SEE ALSO
|
|
|
|
L<ssl(7)>, L<SSL_pending(3)>
|
|
|
|
=head1 COPYRIGHT
|
|
|
|
Copyright 2015-2018 The OpenSSL Project Authors. All Rights Reserved.
|
|
|
|
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
|
|
L<https://www.openssl.org/source/license.html>.
|
|
|
|
=cut
|