d2i_SSL_SESSION.pod revision 279265 
1=pod
2
3=head1 NAME
4
5d2i_SSL_SESSION, i2d_SSL_SESSION - convert SSL_SESSION object from/to ASN1 representation
6
7=head1 SYNOPSIS
8
9 #include <openssl/ssl.h>
10
11 SSL_SESSION *d2i_SSL_SESSION(SSL_SESSION **a, const unsigned char **pp, long length);
12 int i2d_SSL_SESSION(SSL_SESSION *in, unsigned char **pp);
13
14=head1 DESCRIPTION
15
16d2i_SSL_SESSION() transforms the external ASN1 representation of an SSL/TLS
17session, stored as binary data at location B<pp> with length B<length>, into
18an SSL_SESSION object.
19
20i2d_SSL_SESSION() transforms the SSL_SESSION object B<in> into the ASN1
21representation and stores it into the memory location pointed to by B<pp>.
22The length of the resulting ASN1 representation is returned. If B<pp> is
23the NULL pointer, only the length is calculated and returned.
24
25=head1 NOTES
26
27The SSL_SESSION object is built from several malloc()ed parts, it can
28therefore not be moved, copied or stored directly. In order to store
29session data on disk or into a database, it must be transformed into
30a binary ASN1 representation.
31
32When using d2i_SSL_SESSION(), the SSL_SESSION object is automatically
33allocated. The reference count is 1, so that the session must be
34explicitly removed using L<SSL_SESSION_free(3)|SSL_SESSION_free(3)>,
35unless the SSL_SESSION object is completely taken over, when being called
36inside the get_session_cb() (see
37L<SSL_CTX_sess_set_get_cb(3)|SSL_CTX_sess_set_get_cb(3)>).
38
39SSL_SESSION objects keep internal link information about the session cache
40list, when being inserted into one SSL_CTX object's session cache.
41One SSL_SESSION object, regardless of its reference count, must therefore
42only be used with one SSL_CTX object (and the SSL objects created
43from this SSL_CTX object).
44
45When using i2d_SSL_SESSION(), the memory location pointed to by B<pp> must be
46large enough to hold the binary representation of the session. There is no
47known limit on the size of the created ASN1 representation, so the necessary
48amount of space should be obtained by first calling i2d_SSL_SESSION() with
49B<pp=NULL>, and obtain the size needed, then allocate the memory and
50call i2d_SSL_SESSION() again.
51Note that this will advance the value contained in B<*pp> so it is necessary
52to save a copy of the original allocation.
53For example:
54 int i,j;
55 char *p, *temp;
56 i = i2d_SSL_SESSION(sess, NULL);
57 p = temp = malloc(i);
58 j = i2d_SSL_SESSION(sess, &temp);
59 assert(i == j);
60 assert(p+i == temp);
61
62=head1 RETURN VALUES
63
64d2i_SSL_SESSION() returns a pointer to the newly allocated SSL_SESSION
65object. In case of failure the NULL-pointer is returned and the error message
66can be retrieved from the error stack.
67
68i2d_SSL_SESSION() returns the size of the ASN1 representation in bytes.
69When the session is not valid, B<0> is returned and no operation is performed.
70
71=head1 SEE ALSO
72
73L<ssl(3)|ssl(3)>, L<SSL_SESSION_free(3)|SSL_SESSION_free(3)>,
74L<SSL_CTX_sess_set_get_cb(3)|SSL_CTX_sess_set_get_cb(3)>
75
76=cut
77