| yuezonghe | 824eb0c | 2024-06-27 02:32:26 -0700 | [diff] [blame] | 1 | =pod |
| 2 | |
| 3 | =head1 NAME |
| 4 | |
| 5 | SSL_dup, SSL_new, SSL_up_ref - create an SSL structure for a connection |
| 6 | |
| 7 | =head1 SYNOPSIS |
| 8 | |
| 9 | #include <openssl/ssl.h> |
| 10 | |
| 11 | SSL *SSL_dup(SSL *s); |
| 12 | SSL *SSL_new(SSL_CTX *ctx); |
| 13 | int SSL_up_ref(SSL *s); |
| 14 | |
| 15 | =head1 DESCRIPTION |
| 16 | |
| 17 | SSL_new() creates a new B<SSL> structure which is needed to hold the |
| 18 | data for a TLS/SSL connection. The new structure inherits the settings |
| 19 | of the underlying context B<ctx>: connection method, |
| 20 | options, verification settings, timeout settings. An B<SSL> structure is |
| 21 | reference counted. Creating an B<SSL> structure for the first time increments |
| 22 | the reference count. Freeing it (using SSL_free) decrements it. When the |
| 23 | reference count drops to zero, any memory or resources allocated to the B<SSL> |
| 24 | structure are freed. |
| 25 | |
| 26 | SSL_up_ref() increments the reference count for an |
| 27 | existing B<SSL> structure. |
| 28 | |
| 29 | The function SSL_dup() creates and returns a new B<SSL> structure from the same |
| 30 | B<SSL_CTX> that was used to create I<s>. It additionally duplicates a subset of |
| 31 | the settings in I<s> into the new B<SSL> object. |
| 32 | |
| 33 | For SSL_dup() to work, the connection MUST be in its initial state and |
| 34 | MUST NOT have yet started the SSL handshake. For connections that are not in |
| 35 | their initial state SSL_dup() just increments an internal |
| 36 | reference count and returns the I<same> handle. It may be possible to |
| 37 | use L<SSL_clear(3)> to recycle an SSL handle that is not in its initial |
| 38 | state for re-use, but this is best avoided. Instead, save and restore |
| 39 | the session, if desired, and construct a fresh handle for each connection. |
| 40 | |
| 41 | The subset of settings in I<s> that are duplicated are: |
| 42 | |
| 43 | =over 4 |
| 44 | |
| 45 | =item any session data if configured (including the session_id_context) |
| 46 | |
| 47 | =item any tmp_dh settings set via L<SSL_set_tmp_dh(3)>, |
| 48 | L<SSL_set_tmp_dh_callback(3)>, or L<SSL_set_dh_auto(3)> |
| 49 | |
| 50 | =item any configured certificates, private keys or certificate chains |
| 51 | |
| 52 | =item any configured signature algorithms, or client signature algorithms |
| 53 | |
| 54 | =item any DANE settings |
| 55 | |
| 56 | =item any Options set via L<SSL_set_options(3)> |
| 57 | |
| 58 | =item any Mode set via L<SSL_set_mode(3)> |
| 59 | |
| 60 | =item any minimum or maximum protocol settings set via |
| 61 | L<SSL_set_min_proto_version(3)> or L<SSL_set_max_proto_version(3)> (Note: Only |
| 62 | from OpenSSL 1.1.1h and above) |
| 63 | |
| 64 | =item any Verify mode, callback or depth set via L<SSL_set_verify(3)> or |
| 65 | L<SSL_set_verify_depth(3)> or any configured X509 verification parameters |
| 66 | |
| 67 | =item any msg callback or info callback set via L<SSL_set_msg_callback(3)> or |
| 68 | L<SSL_set_info_callback(3)> |
| 69 | |
| 70 | =item any default password callback set via L<SSL_set_default_passwd_cb(3)> |
| 71 | |
| 72 | =item any session id generation callback set via L<SSL_set_generate_session_id(3)> |
| 73 | |
| 74 | =item any configured Cipher List |
| 75 | |
| 76 | =item initial accept (server) or connect (client) state |
| 77 | |
| 78 | =item the max cert list value set via L<SSL_set_max_cert_list(3)> |
| 79 | |
| 80 | =item the read_ahead value set via L<SSL_set_read_ahead(3)> |
| 81 | |
| 82 | =item application specific data set via L<SSL_set_ex_data(3)> |
| 83 | |
| 84 | =item any CA list or client CA list set via L<SSL_set0_CA_list(3)>, |
| 85 | SSL_set0_client_CA_list() or similar functions |
| 86 | |
| 87 | =item any security level settings or callbacks |
| 88 | |
| 89 | =item any configured serverinfo data |
| 90 | |
| 91 | =item any configured PSK identity hint |
| 92 | |
| 93 | =item any configured custom extensions |
| 94 | |
| 95 | =item any client certificate types configured via SSL_set1_client_certificate_types |
| 96 | |
| 97 | =back |
| 98 | |
| 99 | =head1 RETURN VALUES |
| 100 | |
| 101 | The following return values can occur: |
| 102 | |
| 103 | =over 4 |
| 104 | |
| 105 | =item NULL |
| 106 | |
| 107 | The creation of a new SSL structure failed. Check the error stack to |
| 108 | find out the reason. |
| 109 | |
| 110 | =item Pointer to an SSL structure |
| 111 | |
| 112 | The return value points to an allocated SSL structure. |
| 113 | |
| 114 | SSL_up_ref() returns 1 for success and 0 for failure. |
| 115 | |
| 116 | =back |
| 117 | |
| 118 | =head1 SEE ALSO |
| 119 | |
| 120 | L<SSL_free(3)>, L<SSL_clear(3)>, |
| 121 | L<SSL_CTX_set_options(3)>, |
| 122 | L<SSL_get_SSL_CTX(3)>, |
| 123 | L<ssl(7)> |
| 124 | |
| 125 | =head1 COPYRIGHT |
| 126 | |
| 127 | Copyright 2000-2020 The OpenSSL Project Authors. All Rights Reserved. |
| 128 | |
| 129 | Licensed under the OpenSSL license (the "License"). You may not use |
| 130 | this file except in compliance with the License. You can obtain a copy |
| 131 | in the file LICENSE in the source distribution or at |
| 132 | L<https://www.openssl.org/source/license.html>. |
| 133 | |
| 134 | =cut |