| 1 | =pod
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| 2 |
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| 3 | =head1 NAME
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| 4 |
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| 5 | SSL_get_rpoll_descriptor, SSL_get_wpoll_descriptor, SSL_net_read_desired,
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| 6 | SSL_net_write_desired - obtain information which can be used to determine when
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| 7 | network I/O can be performed
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| 8 |
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| 9 | =head1 SYNOPSIS
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| 10 |
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| 11 | #include <openssl/ssl.h>
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| 12 |
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| 13 | int SSL_get_rpoll_descriptor(SSL *s, BIO_POLL_DESCRIPTOR *desc);
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| 14 | int SSL_get_wpoll_descriptor(SSL *s, BIO_POLL_DESCRIPTOR *desc);
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| 15 | int SSL_net_read_desired(SSL *s);
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| 16 | int SSL_net_write_desired(SSL *s);
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| 17 |
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| 18 | =head1 DESCRIPTION
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| 19 |
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| 20 | The functions SSL_get_rpoll_descriptor() and SSL_get_wpoll_descriptor() can be
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| 21 | used to determine when an SSL object which represents a QUIC connection can
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| 22 | perform useful network I/O, so that an application using a QUIC connection SSL
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| 23 | object in nonblocking mode can determine when it should call SSL_handle_events().
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| 24 |
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| 25 | On success, these functions output poll descriptors. For more information on
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| 26 | poll descriptors, see L<BIO_get_rpoll_descriptor(3)>.
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| 27 |
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| 28 | The functions SSL_net_read_desired() and SSL_net_write_desired() return 1 or 0
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| 29 | depending on whether the SSL object is currently interested in receiving data
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| 30 | from the network and/or writing data to the network respectively.
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| 31 | If an SSL object is not interested in reading data from the network at the
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| 32 | current time, SSL_net_read_desired() will return 0; likewise, if an SSL object is
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| 33 | not interested in writing data to the network at the current time,
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| 34 | SSL_net_write_desired() will return 0.
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| 35 |
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| 36 | The intention is that an application using QUIC in nonblocking mode can use
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| 37 | these calls, in conjunction with L<SSL_get_event_timeout(3)> to wait for network
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| 38 | I/O conditions which allow the SSL object to perform useful work. When such a
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| 39 | condition arises, L<SSL_handle_events(3)> should be called.
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| 40 |
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| 41 | In particular, the expected usage is as follows:
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| 42 |
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| 43 | =over 4
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| 44 |
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| 45 | =item *
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| 46 |
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| 47 | SSL_handle_events() should be called whenever the timeout returned by
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| 48 | SSL_get_event_timeout(3) (if any) expires
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| 49 |
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| 50 | =item *
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| 51 |
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| 52 | If the last call to SSL_net_read_desired() returned 1, SSL_handle_events() should be called
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| 53 | whenever the poll descriptor output by SSL_get_rpoll_descriptor() becomes
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| 54 | readable.
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| 55 |
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| 56 | =item *
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| 57 |
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| 58 | If the last call to SSL_net_write_desired() returned 1, SSL_handle_events() should be called
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| 59 | whenever the poll descriptor output by SSL_get_wpoll_descriptor() becomes
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| 60 | writable.
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| 61 |
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| 62 | =back
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| 63 |
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| 64 | The return values of the SSL_net_read_desired() and SSL_net_write_desired() functions
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| 65 | may change in response to any call to the SSL object other than
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| 66 | SSL_net_read_desired(), SSL_net_write_desired(), SSL_get_rpoll_descriptor(),
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| 67 | SSL_get_wpoll_descriptor() and SSL_get_event_timeout().
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| 68 |
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| 69 | On non-QUIC SSL objects, calls to SSL_get_rpoll_descriptor() and
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| 70 | SSL_get_wpoll_descriptor() function the same as calls to
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| 71 | BIO_get_rpoll_descriptor() and BIO_get_wpoll_descriptor() on the respective read
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| 72 | and write BIOs configured on the SSL object.
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| 73 |
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| 74 | On non-QUIC SSL objects, calls to SSL_net_read_desired() and
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| 75 | SSL_net_write_desired() function identically to calls to SSL_want_read() and
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| 76 | SSL_want_write() respectively.
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| 77 |
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| 78 | =head1 RETURN VALUES
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| 79 |
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| 80 | These functions return 1 on success and 0 on failure.
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| 81 |
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| 82 | =head1 SEE ALSO
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| 83 |
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| 84 | L<SSL_handle_events(3)>, L<SSL_get_event_timeout(3)>, L<ssl(7)>
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| 85 |
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| 86 | =head1 HISTORY
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| 87 |
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| 88 | The SSL_get_rpoll_descriptor(), SSL_get_wpoll_descriptor(), SSL_net_read_desired()
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| 89 | and SSL_net_write_desired() functions were added in OpenSSL 3.2.
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| 90 |
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| 91 | =head1 COPYRIGHT
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| 92 |
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| 93 | Copyright 2022-2023 The OpenSSL Project Authors. All Rights Reserved.
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| 94 |
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| 95 | Licensed under the Apache License 2.0 (the "License"). You may not use
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| 96 | this file except in compliance with the License. You can obtain a copy
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| 97 | in the file LICENSE in the source distribution or at
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| 98 | L<https://www.openssl.org/source/license.html>.
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| 99 |
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| 100 | =cut
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