mirror of
https://github.com/openssl/openssl.git
synced 2024-12-09 05:51:54 +08:00
8c1cbc7210
CLA: trivial Reviewed-by: Shane Lontis <shane.lontis@oracle.com> Reviewed-by: Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com> (Merged from https://github.com/openssl/openssl/pull/12320)
70 lines
2.7 KiB
Plaintext
70 lines
2.7 KiB
Plaintext
=pod
|
|
|
|
=head1 NAME
|
|
|
|
SSL_pending, SSL_has_pending - check for readable bytes buffered in an
|
|
SSL object
|
|
|
|
=head1 SYNOPSIS
|
|
|
|
#include <openssl/ssl.h>
|
|
|
|
int SSL_pending(const SSL *ssl);
|
|
int SSL_has_pending(const SSL *s);
|
|
|
|
=head1 DESCRIPTION
|
|
|
|
Data is received in whole blocks known as records from the peer. A whole record
|
|
is processed (e.g. decrypted) in one go and is buffered by OpenSSL until it is
|
|
read by the application via a call to L<SSL_read_ex(3)> or L<SSL_read(3)>.
|
|
|
|
SSL_pending() returns the number of bytes which have been processed, buffered
|
|
and are available inside B<ssl> for immediate read.
|
|
|
|
If the B<SSL> object's I<read_ahead> flag is set (see
|
|
L<SSL_CTX_set_read_ahead(3)>), additional protocol bytes (beyond the current
|
|
record) may have been read containing more TLS/SSL records. This also applies to
|
|
DTLS and pipelining (see L<SSL_CTX_set_split_send_fragment(3)>). These
|
|
additional bytes will be buffered by OpenSSL but will remain unprocessed until
|
|
they are needed. As these bytes are still in an unprocessed state SSL_pending()
|
|
will ignore them. Therefore, it is possible for no more bytes to be readable from
|
|
the underlying BIO (because OpenSSL has already read them) and for SSL_pending()
|
|
to return 0, even though readable application data bytes are available (because
|
|
the data is in unprocessed buffered records).
|
|
|
|
SSL_has_pending() returns 1 if B<s> has buffered data (whether processed or
|
|
unprocessed) and 0 otherwise. Note that it is possible for SSL_has_pending() to
|
|
return 1, and then a subsequent call to SSL_read_ex() or SSL_read() to return no
|
|
data because the unprocessed buffered data when processed yielded no application
|
|
data (for example this can happen during renegotiation). It is also possible in
|
|
this scenario for SSL_has_pending() to continue to return 1 even after an
|
|
SSL_read_ex() or SSL_read() call because the buffered and unprocessed data is
|
|
not yet processable (e.g. because OpenSSL has only received a partial record so
|
|
far).
|
|
|
|
=head1 RETURN VALUES
|
|
|
|
SSL_pending() returns the number of buffered and processed application data
|
|
bytes that are pending and are available for immediate read. SSL_has_pending()
|
|
returns 1 if there is buffered record data in the SSL object and 0 otherwise.
|
|
|
|
=head1 SEE ALSO
|
|
|
|
L<SSL_read_ex(3)>, L<SSL_read(3)>, L<SSL_CTX_set_read_ahead(3)>,
|
|
L<SSL_CTX_set_split_send_fragment(3)>, L<ssl(7)>
|
|
|
|
=head1 HISTORY
|
|
|
|
The SSL_has_pending() function was added in OpenSSL 1.1.0.
|
|
|
|
=head1 COPYRIGHT
|
|
|
|
Copyright 2000-2016 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
|