1=pod
2
3=head1 NAME
4
5SSL_get_session - retrieve TLS/SSL session data
6
7=head1 SYNOPSIS
8
9 #include <openssl/ssl.h>
10
11 SSL_SESSION *SSL_get_session(const SSL *ssl);
12 SSL_SESSION *SSL_get0_session(const SSL *ssl);
13 SSL_SESSION *SSL_get1_session(SSL *ssl);
14
15=head1 DESCRIPTION
16
17SSL_get_session() returns a pointer to the B<SSL_SESSION> actually used in
18B<ssl>. The reference count of the B<SSL_SESSION> is not incremented, so
19that the pointer can become invalid by other operations.
20
21SSL_get0_session() is the same as SSL_get_session().
22
23SSL_get1_session() is the same as SSL_get_session(), but the reference
24count of the B<SSL_SESSION> is incremented by one.
25
26=head1 NOTES
27
28The ssl session contains all information required to re-establish the
29connection without a new handshake.
30
31SSL_get0_session() returns a pointer to the actual session. As the
32reference counter is not incremented, the pointer is only valid while
33the connection is in use. If L<SSL_clear(3)|SSL_clear(3)> or
34L<SSL_free(3)|SSL_free(3)> is called, the session may be removed completely
35(if considered bad), and the pointer obtained will become invalid. Even
36if the session is valid, it can be removed at any time due to timeout
37during L<SSL_CTX_flush_sessions(3)|SSL_CTX_flush_sessions(3)>.
38
39If the data is to be kept, SSL_get1_session() will increment the reference
40count, so that the session will not be implicitly removed by other operations
41but stays in memory. In order to remove the session
42L<SSL_SESSION_free(3)|SSL_SESSION_free(3)> must be explicitly called once
43to decrement the reference count again.
44
45SSL_SESSION objects keep internal link information about the session cache
46list, when being inserted into one SSL_CTX object's session cache.
47One SSL_SESSION object, regardless of its reference count, must therefore
48only be used with one SSL_CTX object (and the SSL objects created
49from this SSL_CTX object).
50
51=head1 RETURN VALUES
52
53The following return values can occur:
54
55=over 4
56
57=item NULL
58
59There is no session available in B<ssl>.
60
61=item Pointer to an SSL
62
63The return value points to the data of an SSL session.
64
65=back
66
67=head1 SEE ALSO
68
69L<ssl(3)|ssl(3)>, L<SSL_free(3)|SSL_free(3)>,
70L<SSL_clear(3)|SSL_clear(3)>,
71L<SSL_SESSION_free(3)|SSL_SESSION_free(3)>
72
73=cut
74