SSL_waiting_for_async, SSL_get_all_async_fds, SSL_get_changed_async_fds - manage
asynchronous operations
#include <openssl/async.h>
#include <openssl/ssl.h>
int SSL_waiting_for_async(SSL *s);
int SSL_get_all_async_fds(SSL *s, OSSL_ASYNC_FD *fd, size_t *numfds);
int SSL_get_changed_async_fds(SSL *s, OSSL_ASYNC_FD *addfd, size_t *numaddfds,
OSSL_ASYNC_FD *delfd, size_t *numdelfds);
SSL_waiting_for_async() determines whether an SSL connection is currently
waiting for asynchronous operations to complete (see the
SSL_MODE_ASYNC
mode in
SSL_CTX_set_mode(3)).
SSL_get_all_async_fds() returns a list of file descriptor which can be
used in a call to
select() or
poll() to determine whether the
current asynchronous operation has completed or not. A completed operation
will result in data appearing as "read ready" on the file descriptor
(no actual data should be read from the file descriptor). This function should
only be called if the
SSL object is currently waiting for asynchronous
work to complete (i.e.
SSL_ERROR_WANT_ASYNC has been received - see
SSL_get_error(3)). Typically the list will only contain one file
descriptor. However, if multiple asynchronous capable engines are in use then
more than one is possible. The number of file descriptors returned is stored
in
*numfds and the file descriptors themselves are in
*fds. The
fds parameter may be NULL in which case no file descriptors are
returned but
*numfds is still populated. It is the callers
responsibility to ensure sufficient memory is allocated at
*fds so
typically this function is called twice (once with a NULL
fds parameter
and once without).
SSL_get_changed_async_fds() returns a list of the asynchronous file
descriptors that have been added and a list that have been deleted since the
last
SSL_ERROR_WANT_ASYNC was received (or since the
SSL object
was created if no
SSL_ERROR_WANT_ASYNC has been received). Similar to
SSL_get_all_async_fds() it is the callers responsibility to ensure that
*addfd and
*delfd have sufficient memory allocated, although
they may be NULL. The number of added fds and the number of deleted fds are
stored in
*numaddfds and
*numdelfds respectively.
SSL_waiting_for_async() will return 1 if the current SSL operation is
waiting for an async operation to complete and 0 otherwise.
SSL_get_all_async_fds() and
SSL_get_changed_async_fds() return 1
on success or 0 on error.
On Windows platforms the
<openssl/async.h> header is dependent on
some of the types customarily made available by including
<windows.h>. The application developer is likely to require
control over when the latter is included, commonly as one of the first
included headers. Therefore, it is defined as an application developer's
responsibility to include
<windows.h> prior to
<openssl/async.h>.
ssl(7),
SSL_get_error(3),
SSL_CTX_set_mode(3)
The
SSL_waiting_for_async(),
SSL_get_all_async_fds() and
SSL_get_changed_async_fds() functions were added in OpenSSL 1.1.0.
Copyright 2016-2021 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>.