| 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_want, SSL_want_nothing, SSL_want_read, SSL_want_write,
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| 6 | SSL_want_x509_lookup, SSL_want_retry_verify, SSL_want_async, SSL_want_async_job,
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| 7 | SSL_want_client_hello_cb - obtain state information TLS/SSL I/O operation
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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_want(const SSL *ssl);
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| 14 | int SSL_want_nothing(const SSL *ssl);
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| 15 | int SSL_want_read(const SSL *ssl);
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| 16 | int SSL_want_write(const SSL *ssl);
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| 17 | int SSL_want_x509_lookup(const SSL *ssl);
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| 18 | int SSL_want_retry_verify(const SSL *ssl);
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| 19 | int SSL_want_async(const SSL *ssl);
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| 20 | int SSL_want_async_job(const SSL *ssl);
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| 21 | int SSL_want_client_hello_cb(const SSL *ssl);
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| 22 |
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| 23 | =head1 DESCRIPTION
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| 24 |
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| 25 | SSL_want() returns state information for the SSL object B<ssl>.
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| 26 |
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| 27 | The other SSL_want_*() calls are shortcuts for the possible states returned
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| 28 | by SSL_want().
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| 29 |
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| 30 | =head1 NOTES
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| 31 |
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| 32 | SSL_want() examines the internal state information of the SSL object. Its
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| 33 | return values are similar to that of L<SSL_get_error(3)>.
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| 34 | Unlike L<SSL_get_error(3)>, which also evaluates the
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| 35 | error queue, the results are obtained by examining an internal state flag
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| 36 | only. The information must therefore only be used for normal operation under
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| 37 | nonblocking I/O. Error conditions are not handled and must be treated
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| 38 | using L<SSL_get_error(3)>.
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| 39 |
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| 40 | The result returned by SSL_want() should always be consistent with
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| 41 | the result of L<SSL_get_error(3)>.
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| 42 |
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| 43 | =head1 RETURN VALUES
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| 44 |
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| 45 | The following return values can currently occur for SSL_want():
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| 46 |
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| 47 | =over 4
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| 48 |
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| 49 | =item SSL_NOTHING
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| 50 |
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| 51 | There is no data to be written or to be read.
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| 52 |
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| 53 | =item SSL_WRITING
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| 54 |
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| 55 | There are data in the SSL buffer that must be written to the underlying
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| 56 | B<BIO> layer in order to complete the actual SSL_*() operation.
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| 57 | A call to L<SSL_get_error(3)> should return B<SSL_ERROR_WANT_WRITE>.
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| 58 |
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| 59 | =item SSL_READING
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| 60 |
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| 61 | More data must be read from the underlying B<BIO> layer in order to
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| 62 | complete the actual SSL_*() operation.
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| 63 | A call to L<SSL_get_error(3)> should return B<SSL_ERROR_WANT_READ>.
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| 64 |
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| 65 | =item SSL_X509_LOOKUP
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| 66 |
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| 67 | The operation did not complete because an application callback set by
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| 68 | SSL_CTX_set_client_cert_cb() has asked to be called again.
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| 69 | A call to L<SSL_get_error(3)> should return B<SSL_ERROR_WANT_X509_LOOKUP>.
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| 70 |
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| 71 | =item SSL_RETRY_VERIFY
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| 72 |
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| 73 | The operation did not complete because an application callback set by
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| 74 | SSL_CTX_set_cert_verify_callback() has asked to be called again.
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| 75 | A call to L<SSL_get_error(3)> should return B<SSL_ERROR_WANT_RETRY_VERIFY>.
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| 76 |
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| 77 | =item SSL_ASYNC_PAUSED
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| 78 |
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| 79 | An asynchronous operation partially completed and was then paused. See
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| 80 | L<SSL_get_all_async_fds(3)>. A call to L<SSL_get_error(3)> should return
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| 81 | B<SSL_ERROR_WANT_ASYNC>.
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| 82 |
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| 83 | =item SSL_ASYNC_NO_JOBS
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| 84 |
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| 85 | The asynchronous job could not be started because there were no async jobs
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| 86 | available in the pool (see ASYNC_init_thread(3)). A call to L<SSL_get_error(3)>
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| 87 | should return B<SSL_ERROR_WANT_ASYNC_JOB>.
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| 88 |
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| 89 | =item SSL_CLIENT_HELLO_CB
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| 90 |
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| 91 | The operation did not complete because an application callback set by
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| 92 | SSL_CTX_set_client_hello_cb() has asked to be called again.
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| 93 | A call to L<SSL_get_error(3)> should return B<SSL_ERROR_WANT_CLIENT_HELLO_CB>.
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| 94 |
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| 95 | =back
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| 96 |
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| 97 | SSL_want_nothing(), SSL_want_read(), SSL_want_write(),
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| 98 | SSL_want_x509_lookup(), SSL_want_retry_verify(),
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| 99 | SSL_want_async(), SSL_want_async_job(), and SSL_want_client_hello_cb()
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| 100 | return 1 when the corresponding condition is true or 0 otherwise.
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| 101 |
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| 102 | =head1 SEE ALSO
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| 103 |
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| 104 | L<ssl(7)>, L<SSL_get_error(3)>
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| 105 |
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| 106 | =head1 HISTORY
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| 107 |
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| 108 | The SSL_want_client_hello_cb() function and the SSL_CLIENT_HELLO_CB return value
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| 109 | were added in OpenSSL 1.1.1.
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| 110 |
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| 111 | =head1 COPYRIGHT
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| 112 |
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| 113 | Copyright 2001-2021 The OpenSSL Project Authors. All Rights Reserved.
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| 114 |
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| 115 | Licensed under the Apache License 2.0 (the "License"). You may not use
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| 116 | this file except in compliance with the License. You can obtain a copy
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| 117 | in the file LICENSE in the source distribution or at
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| 118 | L<https://www.openssl.org/source/license.html>.
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| 119 |
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| 120 | =cut
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