D2I_SSL_SESSION(3) BSD Library Functions Manual D2I_SSL_SESSION(3)NAME
d2i_SSL_SESSION, i2d_SSL_SESSION — convert SSL_SESSION object from/to
ASN1 representation
SYNOPSIS
#include <openssl/ssl.h>
SSL_SESSION *
d2i_SSL_SESSION(SSL_SESSION **a, const unsigned char **pp, long length);
int
i2d_SSL_SESSION(SSL_SESSION *in, unsigned char **pp);
DESCRIPTIONd2i_SSL_SESSION() transforms the external ASN1 representation of an
SSL/TLS session, stored as binary data at location pp with length length,
into an SSL_SESSION object.
i2d_SSL_SESSION() transforms the SSL_SESSION object in into the ASN1 rep‐
resentation and stores it into the memory location pointed to by pp. The
length of the resulting ASN1 representation is returned. If pp is the
NULL pointer, only the length is calculated and returned.
NOTES
The SSL_SESSION object is built from several malloc(3)-ed parts; it can
therefore not be moved, copied or stored directly. In order to store
session data on disk or into a database, it must be transformed into a
binary ASN1 representation.
When using d2i_SSL_SESSION(), the SSL_SESSION object is automatically
allocated. The reference count is 1, so that the session must be explic‐
itly removed using SSL_SESSION_free(3), unless the SSL_SESSION object is
completely taken over, when being called inside the get_session_cb(3)
(see SSL_CTX_sess_set_get_cb(3)).
SSL_SESSION objects keep internal link information about the session
cache list when being inserted into one SSL_CTX object's session cache.
One SSL_SESSION object, regardless of its reference count, must therefore
only be used with one SSL_CTX object (and the SSL objects created from
this SSL_CTX object).
When using i2d_SSL_SESSION(), the memory location pointed to by pp must
be large enough to hold the binary representation of the session. There
is no known limit on the size of the created ASN1 representation, so the
necessary amount of space should be obtained by first calling
i2d_SSL_SESSION() with pp= Ns NULL, and obtain the size needed, then
allocate the memory and call i2d_SSL_SESSION() again. Note that this
will advance the value contained in *pp so it is necessary to save a copy
of the original allocation. For example:
int i, j;
char *p, *temp;
i = i2d_SSL_SESSION(sess, NULL);
p = temp = malloc(i);
if (temp != NULL) {
j = i2d_SSL_SESSION(sess, &temp);
assert(i == j);
assert(p + i == temp);
}
RETURN VALUESd2i_SSL_SESSION() returns a pointer to the newly allocated SSL_SESSION
object. In case of failure a NULL pointer is returned and the error mes‐
sage can be retrieved from the error stack.
i2d_SSL_SESSION() returns the size of the ASN1 representation in bytes.
When the session is not valid, 0 is returned and no operation is per‐
formed.
SEE ALSOssl(3), SSL_CTX_sess_set_get_cb(3), SSL_SESSION_free(3)BSD April 18, 2024 BSD
