i2d_SSL_SESSION (3)

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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);

DESCRIPTION

d2i_SSL_SESSION() transforms the external representation of an session, stored as binary data at location pp with length length, into an object.

i2d_SSL_SESSION() transforms the

object in into the representation and stores it into the memory location pointed to by pp. The length of the resulting representation is returned. If pp is the pointer, only the length is calculated and returned.

NOTES

The object is built from several malloc()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 representation.

When using d2i_SSL_SESSION(), the

object is automatically allocated. The reference count is 1, so that the session must be explicitly removed using SSL_SESSION_free(3), unless the object is completely taken over, when being called inside the get_session_cb() (see SSL_CTX_sess_set_get_cb(3)).

objects keep internal link information about the session cache list, when being inserted into one object's session cache. One object, regardless of its reference count, must therefore only be used with one object (and the objects created from this 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

representation, so the necessary amount of space should be obtained by first calling i2d_SSL_SESSION() with pp=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, );
 p = temp = malloc(i);
 j = i2d_SSL_SESSION(sess, &temp);
 assert(i == j);
 assert(p+i == temp);

RETURN VALUES

d2i_SSL_SESSION() returns a pointer to the newly allocated object. In case of failure the NULL-pointer is returned and the error message can be retrieved from the error stack.

i2d_SSL_SESSION() returns the size of the

representation in bytes. When the session is not valid, 0 is returned and no operation is performed.

SEE ALSO

ssl(3), SSL_SESSION_free(3), SSL_CTX_sess_set_get_cb(3)