NAME

SYNOPSIS

 #include <openssl/objects.h>

 ASN1_OBJECT *OBJ_nid2obj(int n);
 const char *OBJ_nid2ln(int n);
 const char *OBJ_nid2sn(int n);

 int OBJ_obj2nid(const ASN1_OBJECT *o);
 int OBJ_ln2nid(const char *ln);
 int OBJ_sn2nid(const char *sn);

 int OBJ_txt2nid(const char *s);

 ASN1_OBJECT *OBJ_txt2obj(const char *s, int no_name);
 int OBJ_obj2txt(char *buf, int buf_len, const ASN1_OBJECT *a, int no_name);

 int i2t_ASN1_OBJECT(char *buf, int buf_len, const ASN1_OBJECT *a);

 int OBJ_cmp(const ASN1_OBJECT *a, const ASN1_OBJECT *b);
 ASN1_OBJECT *OBJ_dup(const ASN1_OBJECT *o);

 int OBJ_create(const char *oid, const char *sn, const char *ln);

 size_t OBJ_length(const ASN1_OBJECT *obj);
 const unsigned char *OBJ_get0_data(const ASN1_OBJECT *obj);

Deprecated:

 #if OPENSSL_API_COMPAT < 0x10100000L
 void OBJ_cleanup(void)
 #endif

DESCRIPTION

OBJ_nid2obj(), OBJ_nid2ln() and OBJ_nid2sn() convert the NID n to an ASN1_OBJECT structure, its long name and its short name respectively, or NULL if an error occurred.

OBJ_obj2nid(), OBJ_ln2nid(), OBJ_sn2nid() return the corresponding NID for the object o, the long name <ln> or the short name <sn> respectively or NID_undef if an error occurred.

OBJ_txt2nid() returns NID corresponding to text string s. s can be a long name, a short name or the numerical representation of an object.

OBJ_txt2obj() converts the text string s into an ASN1_OBJECT structure. If no_name is 0 then long names and short names will be interpreted as well as numerical forms. If no_name is 1 only the numerical form is acceptable.

OBJ_obj2txt() converts the ASN1_OBJECT a into a textual representation. Unless buf is NULL, the representation is written as a NUL-terminated string to buf, where at most buf_len bytes are written, truncating the result if necessary. In any case it returns the total string length, excluding the NUL character, required for non-truncated representation, or -1 on error. If no_name is 0 then if the object has a long or short name then that will be used, otherwise the numerical form will be used. If no_name is 1 then the numerical form will always be used.

i2t_ASN1_OBJECT() is the same as OBJ_obj2txt() with the no_name set to zero.

OBJ_cmp() compares a to b. If the two are identical 0 is returned.

OBJ_dup() returns a copy of o.

OBJ_create() adds a new object to the internal table. oid is the numerical form of the object, sn the short name and ln the long name. A new NID is returned for the created object in case of success and NID_undef in case of failure.

OBJ_length() returns the size of the content octets of obj.

OBJ_get0_data() returns a pointer to the content octets of obj. The returned pointer is an internal pointer which must not be freed.

OBJ_cleanup() releases any resources allocated by creating new objects.

NOTES

For example the OID for commonName has the following definitions:

 #define SN_commonName                   "CN"
 #define LN_commonName                   "commonName"
 #define NID_commonName                  13

New objects can be added by calling OBJ_create().

Table objects have certain advantages over other objects: for example their NIDs can be used in a C language switch statement. They are also static constant structures which are shared: that is there is only a single constant structure for each table object.

Objects which are not in the table have the NID value NID_undef.

Objects do not need to be in the internal tables to be processed, the functions OBJ_txt2obj() and OBJ_obj2txt() can process the numerical form of an OID.

Some objects are used to represent algorithms which do not have a corresponding ASN.1 OBJECT IDENTIFIER encoding (for example no OID currently exists for a particular algorithm). As a result they cannot be encoded or decoded as part of ASN.1 structures. Applications can determine if there is a corresponding OBJECT IDENTIFIER by checking OBJ_length() is not zero.

These functions cannot return const because an ASN1_OBJECT can represent both an internal, constant, OID and a dynamically-created one. The latter cannot be constant because it needs to be freed after use.

RETURN VALUES

OBJ_nid2ln() and OBJ_nid2sn() returns a valid string or NULL on error.

OBJ_obj2nid(), OBJ_ln2nid(), OBJ_sn2nid() and OBJ_txt2nid() return a NID or NID_undef on error.

OBJ_add_sigid() returns 1 on success or 0 on error.

i2t_ASN1_OBJECT() an OBJ_obj2txt() return -1 on error. On success, they return the length of the string written to buf if buf is not NULL and buf_len is big enough, otherwise the total string length. Note that this does not count the trailing NUL character.

EXAMPLES

 ASN1_OBJECT *o = OBJ_nid2obj(NID_commonName);

Check if an object is commonName

 if (OBJ_obj2nid(obj) == NID_commonName)
     /* Do something */

Create a new NID and initialize an object from it:

 int new_nid = OBJ_create("1.2.3.4", "NewOID", "New Object Identifier");
 ASN1_OBJECT *obj = OBJ_nid2obj(new_nid);

Create a new object directly:

 obj = OBJ_txt2obj("1.2.3.4", 1);

SEE ALSO

HISTORY

COPYRIGHT

Licensed under the OpenSSL license (the "License"). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at <https://www.openssl.org/source/license.html>.