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1 | =pod | |
2 | ||
3 | =head1 NAME | |
4 | ||
5 | SSL_SESSION_new, | |
6 | SSL_SESSION_dup, | |
7 | SSL_SESSION_up_ref, | |
8 | SSL_SESSION_free - create, free and manage SSL_SESSION structures | |
9 | ||
10 | =head1 SYNOPSIS | |
11 | ||
12 | #include <openssl/ssl.h> | |
13 | ||
14 | SSL_SESSION *SSL_SESSION_new(void); | |
15 | SSL_SESSION *SSL_SESSION_dup(const SSL_SESSION *src); | |
16 | int SSL_SESSION_up_ref(SSL_SESSION *ses); | |
17 | void SSL_SESSION_free(SSL_SESSION *session); | |
18 | ||
19 | =head1 DESCRIPTION | |
20 | ||
21 | SSL_SESSION_new() creates a new SSL_SESSION structure and returns a pointer to | |
22 | it. | |
23 | ||
24 | SSL_SESSION_dup() copies the contents of the SSL_SESSION structure in B<src> | |
25 | and returns a pointer to it. | |
26 | ||
27 | SSL_SESSION_up_ref() increments the reference count on the given SSL_SESSION | |
28 | structure. | |
29 | ||
30 | SSL_SESSION_free() decrements the reference count of B<session> and removes | |
31 | the B<SSL_SESSION> structure pointed to by B<session> and frees up the allocated | |
32 | memory, if the reference count has reached 0. | |
33 | If B<session> is NULL nothing is done. | |
34 | ||
35 | =head1 NOTES | |
36 | ||
37 | SSL_SESSION objects are allocated, when a TLS/SSL handshake operation | |
38 | is successfully completed. Depending on the settings, see | |
39 | L<SSL_CTX_set_session_cache_mode(3)>, | |
40 | the SSL_SESSION objects are internally referenced by the SSL_CTX and | |
41 | linked into its session cache. SSL objects may be using the SSL_SESSION object; | |
42 | as a session may be reused, several SSL objects may be using one SSL_SESSION | |
43 | object at the same time. It is therefore crucial to keep the reference | |
44 | count (usage information) correct and not delete a SSL_SESSION object | |
45 | that is still used, as this may lead to program failures due to | |
46 | dangling pointers. These failures may also appear delayed, e.g. | |
47 | when an SSL_SESSION object was completely freed as the reference count | |
48 | incorrectly became 0, but it is still referenced in the internal | |
49 | session cache and the cache list is processed during a | |
50 | L<SSL_CTX_flush_sessions(3)> operation. | |
51 | ||
52 | SSL_SESSION_free() must only be called for SSL_SESSION objects, for | |
53 | which the reference count was explicitly incremented (e.g. | |
54 | by calling SSL_get1_session(), see L<SSL_get_session(3)>) | |
55 | or when the SSL_SESSION object was generated outside a TLS handshake | |
56 | operation, e.g. by using L<d2i_SSL_SESSION(3)>. | |
57 | It must not be called on other SSL_SESSION objects, as this would cause | |
58 | incorrect reference counts and therefore program failures. | |
59 | ||
60 | =head1 RETURN VALUES | |
61 | ||
62 | SSL_SESSION_new returns a pointer to the newly allocated SSL_SESSION structure | |
63 | or NULL on error. | |
64 | ||
65 | SSL_SESSION_up_ref returns 1 on success or 0 on error. | |
66 | ||
67 | =head1 SEE ALSO | |
68 | ||
69 | L<ssl(7)>, L<SSL_get_session(3)>, | |
70 | L<SSL_CTX_set_session_cache_mode(3)>, | |
71 | L<SSL_CTX_flush_sessions(3)>, | |
72 | L<d2i_SSL_SESSION(3)> | |
73 | ||
74 | =head1 HISTORY | |
75 | ||
76 | The SSL_SESSION_dup() function was added in OpenSSL 1.1.1. | |
77 | ||
78 | =head1 COPYRIGHT | |
79 | ||
80 | Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved. | |
81 | ||
82 | Licensed under the Apache License 2.0 (the "License"). You may not use | |
83 | this file except in compliance with the License. You can obtain a copy | |
84 | in the file LICENSE in the source distribution or at | |
85 | L<https://www.openssl.org/source/license.html>. | |
86 | ||
87 | =cut |