SSL_get_session.pod revision 337982 
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>
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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().
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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
31A session will be automatically removed from the session cache and marked as
32non-resumable if the connection is not closed down cleanly, e.g. if a fatal
33error occurs on the connection or L<SSL_shutdown(3)> is not called prior to
34L<SSL_free(3)>.
35
36SSL_get0_session() returns a pointer to the actual session. As the
37reference counter is not incremented, the pointer is only valid while
38the connection is in use. If L<SSL_clear(3)|SSL_clear(3)> or
39L<SSL_free(3)|SSL_free(3)> is called, the session may be removed completely
40(if considered bad), and the pointer obtained will become invalid. Even
41if the session is valid, it can be removed at any time due to timeout
42during L<SSL_CTX_flush_sessions(3)|SSL_CTX_flush_sessions(3)>.
43
44If the data is to be kept, SSL_get1_session() will increment the reference
45count, so that the session will not be implicitly removed by other operations
46but stays in memory. In order to remove the session
47L<SSL_SESSION_free(3)|SSL_SESSION_free(3)> must be explicitly called once
48to decrement the reference count again.
49
50SSL_SESSION objects keep internal link information about the session cache
51list, when being inserted into one SSL_CTX object's session cache.
52One SSL_SESSION object, regardless of its reference count, must therefore
53only be used with one SSL_CTX object (and the SSL objects created
54from this SSL_CTX object).
55
56=head1 RETURN VALUES
57
58The following return values can occur:
59
60=over 4
61
62=item NULL
63
64There is no session available in B<ssl>.
65
66=item Pointer to an SSL
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68The return value points to the data of an SSL session.
69
70=back
71
72=head1 SEE ALSO
73
74L<ssl(3)|ssl(3)>, L<SSL_free(3)|SSL_free(3)>,
75L<SSL_clear(3)|SSL_clear(3)>,
76L<SSL_SESSION_free(3)|SSL_SESSION_free(3)>
77
78=cut
79