| yuezonghe | 824eb0c | 2024-06-27 02:32:26 -0700 | [diff] [blame^] | 1 | =pod |
| 2 | |
| 3 | =head1 NAME |
| 4 | |
| 5 | SSL_want, SSL_want_nothing, SSL_want_read, SSL_want_write, SSL_want_x509_lookup, |
| 6 | SSL_want_async, SSL_want_async_job, SSL_want_client_hello_cb - obtain state |
| 7 | information TLS/SSL I/O operation |
| 8 | |
| 9 | =head1 SYNOPSIS |
| 10 | |
| 11 | #include <openssl/ssl.h> |
| 12 | |
| 13 | int SSL_want(const SSL *ssl); |
| 14 | int SSL_want_nothing(const SSL *ssl); |
| 15 | int SSL_want_read(const SSL *ssl); |
| 16 | int SSL_want_write(const SSL *ssl); |
| 17 | int SSL_want_x509_lookup(const SSL *ssl); |
| 18 | int SSL_want_async(const SSL *ssl); |
| 19 | int SSL_want_async_job(const SSL *ssl); |
| 20 | int SSL_want_client_hello_cb(const SSL *ssl); |
| 21 | |
| 22 | =head1 DESCRIPTION |
| 23 | |
| 24 | SSL_want() returns state information for the SSL object B<ssl>. |
| 25 | |
| 26 | The other SSL_want_*() calls are shortcuts for the possible states returned |
| 27 | by SSL_want(). |
| 28 | |
| 29 | =head1 NOTES |
| 30 | |
| 31 | SSL_want() examines the internal state information of the SSL object. Its |
| 32 | return values are similar to that of L<SSL_get_error(3)>. |
| 33 | Unlike L<SSL_get_error(3)>, which also evaluates the |
| 34 | error queue, the results are obtained by examining an internal state flag |
| 35 | only. The information must therefore only be used for normal operation under |
| 36 | nonblocking I/O. Error conditions are not handled and must be treated |
| 37 | using L<SSL_get_error(3)>. |
| 38 | |
| 39 | The result returned by SSL_want() should always be consistent with |
| 40 | the result of L<SSL_get_error(3)>. |
| 41 | |
| 42 | =head1 RETURN VALUES |
| 43 | |
| 44 | The following return values can currently occur for SSL_want(): |
| 45 | |
| 46 | =over 4 |
| 47 | |
| 48 | =item SSL_NOTHING |
| 49 | |
| 50 | There is no data to be written or to be read. |
| 51 | |
| 52 | =item SSL_WRITING |
| 53 | |
| 54 | There are data in the SSL buffer that must be written to the underlying |
| 55 | B<BIO> layer in order to complete the actual SSL_*() operation. |
| 56 | A call to L<SSL_get_error(3)> should return |
| 57 | SSL_ERROR_WANT_WRITE. |
| 58 | |
| 59 | =item SSL_READING |
| 60 | |
| 61 | More data must be read from the underlying B<BIO> layer in order to |
| 62 | complete the actual SSL_*() operation. |
| 63 | A call to L<SSL_get_error(3)> should return |
| 64 | SSL_ERROR_WANT_READ. |
| 65 | |
| 66 | =item SSL_X509_LOOKUP |
| 67 | |
| 68 | The operation did not complete because an application callback set by |
| 69 | SSL_CTX_set_client_cert_cb() has asked to be called again. |
| 70 | A call to L<SSL_get_error(3)> should return |
| 71 | SSL_ERROR_WANT_X509_LOOKUP. |
| 72 | |
| 73 | =item SSL_ASYNC_PAUSED |
| 74 | |
| 75 | An asynchronous operation partially completed and was then paused. See |
| 76 | L<SSL_get_all_async_fds(3)>. A call to L<SSL_get_error(3)> should return |
| 77 | SSL_ERROR_WANT_ASYNC. |
| 78 | |
| 79 | =item SSL_ASYNC_NO_JOBS |
| 80 | |
| 81 | The asynchronous job could not be started because there were no async jobs |
| 82 | available in the pool (see ASYNC_init_thread(3)). A call to L<SSL_get_error(3)> |
| 83 | should return SSL_ERROR_WANT_ASYNC_JOB. |
| 84 | |
| 85 | =item SSL_CLIENT_HELLO_CB |
| 86 | |
| 87 | The operation did not complete because an application callback set by |
| 88 | SSL_CTX_set_client_hello_cb() has asked to be called again. |
| 89 | A call to L<SSL_get_error(3)> should return |
| 90 | SSL_ERROR_WANT_CLIENT_HELLO_CB. |
| 91 | |
| 92 | =back |
| 93 | |
| 94 | SSL_want_nothing(), SSL_want_read(), SSL_want_write(), SSL_want_x509_lookup(), |
| 95 | SSL_want_async(), SSL_want_async_job(), and SSL_want_client_hello_cb() return |
| 96 | 1, when the corresponding condition is true or 0 otherwise. |
| 97 | |
| 98 | =head1 SEE ALSO |
| 99 | |
| 100 | L<ssl(7)>, L<SSL_get_error(3)> |
| 101 | |
| 102 | =head1 HISTORY |
| 103 | |
| 104 | The SSL_want_client_hello_cb() function and the SSL_CLIENT_HELLO_CB return value |
| 105 | were added in OpenSSL 1.1.1. |
| 106 | |
| 107 | =head1 COPYRIGHT |
| 108 | |
| 109 | Copyright 2001-2020 The OpenSSL Project Authors. All Rights Reserved. |
| 110 | |
| 111 | Licensed under the OpenSSL license (the "License"). You may not use |
| 112 | this file except in compliance with the License. You can obtain a copy |
| 113 | in the file LICENSE in the source distribution or at |
| 114 | L<https://www.openssl.org/source/license.html>. |
| 115 | |
| 116 | =cut |