SSL_GET_RPOLL_DESCRIPTOR(3ossl) OpenSSL SSL_GET_RPOLL_DESCRIPTOR(3ossl)
NAME
SSL_get_rpoll_descriptor, SSL_get_wpoll_descriptor,
SSL_net_read_desired, SSL_net_write_desired - obtain information which
can be used to determine when network I/O can be performed
SYNOPSIS
#include <openssl/ssl.h>
int SSL_get_rpoll_descriptor(SSL *s, BIO_POLL_DESCRIPTOR *desc);
int SSL_get_wpoll_descriptor(SSL *s, BIO_POLL_DESCRIPTOR *desc);
int SSL_net_read_desired(SSL *s);
int SSL_net_write_desired(SSL *s);
DESCRIPTION
The functions SSL_get_rpoll_descriptor(3) and SSL_get_wpoll_descriptor()
can be used to determine when an SSL object which represents a QUIC
connection can perform useful network I/O, so that an application using
a QUIC connection SSL object in nonblocking mode can determine when it
should call SSL_handle_events().
On success, these functions output poll descriptors. For more
information on poll descriptors, see BIO_get_rpoll_descriptor(3).
The functions SSL_net_read_desired() and SSL_net_write_desired() return
1 or 0 depending on whether the SSL object is currently interested in
receiving data from the network and/or writing data to the network
respectively. If an SSL object is not interested in reading data from
the network at the current time, SSL_net_read_desired() will return 0;
likewise, if an SSL object is not interested in writing data to the
network at the current time, SSL_net_write_desired() will return 0.
The intention is that an application using QUIC in nonblocking mode can
use these calls, in conjunction with SSL_get_event_timeout(3) to wait
for network I/O conditions which allow the SSL object to perform useful
work. When such a condition arises, SSL_handle_events(3) should be
called.
In particular, the expected usage is as follows:
o SSL_handle_events() should be called whenever the timeout returned
by SSL_get_event_timeout(3) (if any) expires
o If the last call to SSL_net_read_desired() returned 1,
SSL_handle_events() should be called whenever the poll descriptor
output by SSL_get_rpoll_descriptor(3) becomes readable.
o If the last call to SSL_net_write_desired() returned 1,
SSL_handle_events() should be called whenever the poll descriptor
output by SSL_get_wpoll_descriptor() becomes writable.
The return values of the SSL_net_read_desired() and
SSL_net_write_desired() functions may change in response to any call to
the SSL object other than SSL_net_read_desired(),
SSL_get_rpoll_descriptor(3),
SSL_get_wpoll_descriptor() and SSL_get_event_timeout().
On non-QUIC SSL objects, calls to SSL_get_rpoll_descriptor(3) and
SSL_get_wpoll_descriptor() function the same as calls to
BIO_get_rpoll_descriptor() and BIO_get_wpoll_descriptor() on the
respective read and write BIOs configured on the SSL object.
On non-QUIC SSL objects, calls to SSL_net_read_desired() and
SSL_net_write_desired() function identically to calls to
SSL_want_read() and SSL_want_write() respectively.
RETURN VALUES
These functions return 1 on success and 0 on failure.
SEE ALSO
SSL_handle_events(3), SSL_get_event_timeout(3), ssl(7)
HISTORY
The SSL_get_rpoll_descriptor(3), SSL_get_wpoll_descriptor(),
SSL_net_read_desired() and SSL_net_write_desired() functions were added
in OpenSSL 3.2.
COPYRIGHT
Copyright 2022-2023 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
<https://www.openssl.org/source/license.html>.
3.3.2 2024-09-04 SSL_GET_RPOLL_DESCRIPTOR(3ossl)
openssl 3.3.2 - Generated Thu Sep 26 15:50:17 CDT 2024