## libtasn1 libtasn1 |

## Functions

int | asn1_parser2tree ()
int | asn1_parser2array ()
int | asn1_array2tree ()
void | asn1_print_structure ()
int | asn1_create_element ()
int | asn1_delete_structure ()
int | asn1_delete_structure2 ()
int | asn1_delete_element ()
int | asn1_write_value ()
int | asn1_read_value ()
int | asn1_read_value_type ()
int | asn1_read_node_value ()
int | asn1_number_of_elements ()
int | asn1_der_coding ()
int | asn1_der_decoding2 ()
int | asn1_der_decoding ()
int | asn1_der_decoding_element ()
int | asn1_der_decoding_startEnd ()
int | asn1_expand_any_defined_by ()
int | asn1_expand_octet_string ()
int | asn1_read_tag ()
const char * | asn1_find_structure_from_oid ()
const char * | asn1_check_version ()
const char * | asn1_strerror ()
void | asn1_perror ()
#define | ASN1_MAX_TL_SIZE
long | asn1_get_length_der ()
long | asn1_get_length_ber ()
void | asn1_length_der ()
int | asn1_decode_simple_der ()
int | asn1_encode_simple_der ()
asn1_node | asn1_find_node ()
int | asn1_copy_node ()
asn1_node | asn1_dup_node ()
int | asn1_get_tag_der ()
void | asn1_octet_der ()
int | asn1_get_octet_der ()
void | asn1_bit_der ()
int | asn1_get_bit_der ()

## Types and Values

#define | ASN1_API
#define | ASN1_VERSION
#define | ASN1_SUCCESS
#define | ASN1_FILE_NOT_FOUND
#define | ASN1_ELEMENT_NOT_FOUND
#define | ASN1_IDENTIFIER_NOT_FOUND
#define | ASN1_DER_ERROR
#define | ASN1_VALUE_NOT_FOUND
#define | ASN1_GENERIC_ERROR
#define | ASN1_VALUE_NOT_VALID
#define | ASN1_TAG_ERROR
#define | ASN1_TAG_IMPLICIT
#define | ASN1_ERROR_TYPE_ANY
#define | ASN1_SYNTAX_ERROR
#define | ASN1_MEM_ERROR
#define | ASN1_MEM_ALLOC_ERROR
#define | ASN1_DER_OVERFLOW
#define | ASN1_NAME_TOO_LONG
#define | ASN1_ARRAY_ERROR
#define | ASN1_ELEMENT_NOT_EMPTY
#define | ASN1_PRINT_NAME
#define | ASN1_PRINT_NAME_TYPE
#define | ASN1_PRINT_NAME_TYPE_VALUE
#define | ASN1_PRINT_ALL
#define | ASN1_CLASS_UNIVERSAL
#define | ASN1_CLASS_APPLICATION
#define | ASN1_CLASS_CONTEXT_SPECIFIC
#define | ASN1_CLASS_PRIVATE
#define | ASN1_CLASS_STRUCTURED
#define | ASN1_TAG_BOOLEAN
#define | ASN1_TAG_INTEGER
#define | ASN1_TAG_SEQUENCE
#define | ASN1_TAG_SET
#define | ASN1_TAG_OCTET_STRING
#define | ASN1_TAG_BIT_STRING
#define | ASN1_TAG_UTCTime
#define | ASN1_TAG_GENERALIZEDTime
#define | ASN1_TAG_OBJECT_ID
#define | ASN1_TAG_ENUMERATED
#define | ASN1_TAG_NULL
#define | ASN1_TAG_GENERALSTRING
#define | ASN1_TAG_NUMERIC_STRING
#define | ASN1_TAG_IA5_STRING
#define | ASN1_TAG_TELETEX_STRING
#define | ASN1_TAG_PRINTABLE_STRING
#define | ASN1_TAG_UNIVERSAL_STRING
#define | ASN1_TAG_BMP_STRING
#define | ASN1_TAG_UTF8_STRING
#define | ASN1_TAG_VISIBLE_STRING
typedef | asn1_node_st
typedef | asn1_node
#define | ASN1_MAX_NAME_SIZE
typedef | asn1_static_node
#define | ASN1_ETYPE_INVALID
#define | ASN1_ETYPE_CONSTANT
#define | ASN1_ETYPE_IDENTIFIER
#define | ASN1_ETYPE_INTEGER
#define | ASN1_ETYPE_BOOLEAN
#define | ASN1_ETYPE_SEQUENCE
#define | ASN1_ETYPE_BIT_STRING
#define | ASN1_ETYPE_OCTET_STRING
#define | ASN1_ETYPE_TAG
#define | ASN1_ETYPE_DEFAULT
#define | ASN1_ETYPE_SIZE
#define | ASN1_ETYPE_SEQUENCE_OF
#define | ASN1_ETYPE_OBJECT_ID
#define | ASN1_ETYPE_ANY
#define | ASN1_ETYPE_SET
#define | ASN1_ETYPE_SET_OF
#define | ASN1_ETYPE_DEFINITIONS
#define | ASN1_ETYPE_CHOICE
#define | ASN1_ETYPE_IMPORTS
#define | ASN1_ETYPE_NULL
#define | ASN1_ETYPE_ENUMERATED
#define | ASN1_ETYPE_GENERALSTRING
#define | ASN1_ETYPE_NUMERIC_STRING
#define | ASN1_ETYPE_IA5_STRING
#define | ASN1_ETYPE_TELETEX_STRING
#define | ASN1_ETYPE_PRINTABLE_STRING
#define | ASN1_ETYPE_UNIVERSAL_STRING
#define | ASN1_ETYPE_BMP_STRING
#define | ASN1_ETYPE_UTF8_STRING
#define | ASN1_ETYPE_VISIBLE_STRING
#define | ASN1_ETYPE_UTC_TIME
#define | ASN1_ETYPE_GENERALIZED_TIME
#define | ASN1_DELETE_FLAG_ZEROIZE
#define | ASN1_DECODE_FLAG_ALLOW_PADDING
typedef | asn1_data_node_st
#define | ASN1_MAX_ERROR_DESCRIPTION_SIZE
#define | ASN1_MAX_TAG_SIZE
#define | ASN1_MAX_LENGTH_SIZE
typedef | asn1_retCode
#define | node_asn_struct
#define | node_asn
#define | ASN1_TYPE
#define | ASN1_TYPE_EMPTY
#define | static_struct_asn
#define | ASN1_ARRAY_TYPE
#define | asn1_static_node_t
#define | node_data_struct
#define | ASN1_DATA_NODE

## Object Hierarchy

## Description

## Functions

### asn1_parser2tree ()

    int
    asn1_parser2tree (const char *file,
                      asn1_node *definitions,
                      char *error_desc);

Function used to start the parse algorithm. Creates the structures needed to manage the definitions included in `file` file.

#### Parameters

file | specify the path and the name of file that contains ASN.1 declarations. |
definitions | return the pointer to the structure created from "file" ASN.1 declarations. |
error_desc | return the error description or an empty string if success. |

#### Returns

`ASN1_SUCCESS` if the file has a correct syntax and every identifier is known, `ASN1_ELEMENT_NOT_EMPTY` if `definitions` not `NULL`, `ASN1_FILE_NOT_FOUND` if an error occured while opening `file` , `ASN1_SYNTAX_ERROR` if the syntax is not correct, `ASN1_IDENTIFIER_NOT_FOUND` if in the file there is an identifier that is not defined, `ASN1_NAME_TOO_LONG` if in the file there is an identifier whith more than `ASN1_MAX_NAME_SIZE` characters.

### asn1_parser2array ()

    int
    asn1_parser2array (const char *inputFileName,
                       const char *outputFileName,
                       const char *vectorName,
                       char *error_desc);

Function that generates a C structure from an ASN1 file. Creates a file containing a C vector to use to manage the definitions included in `inputFileName` file. If `inputFileName` is "/aa/bb/xx.yy" and `outputFileName` is `NULL`, the file created is "/aa/bb/xx_asn1_tab.c". If `vectorName` is `NULL` the vector name will be "xx_asn1_tab".

#### Parameters

inputFileName | specify the path and the name of file that contains ASN.1 declarations. |
outputFileName | specify the path and the name of file that will contain the C vector definition. |
vectorName | specify the name of the C vector. |
error_desc | return the error description or an empty string if success. |

#### Returns

`ASN1_SUCCESS` if the file has a correct syntax and every identifier is known, `ASN1_FILE_NOT_FOUND` if an error occured while opening `inputFileName` , `ASN1_SYNTAX_ERROR` if the syntax is not correct, `ASN1_IDENTIFIER_NOT_FOUND` if in the file there is an identifier that is not defined, `ASN1_NAME_TOO_LONG` if in the file there is an identifier whith more than `ASN1_MAX_NAME_SIZE` characters.

### asn1_array2tree ()

    int
    asn1_array2tree (const asn1_static_node *array,
                     asn1_node *definitions,
                     char *errorDescription);

Creates the structures needed to manage the ASN.1 definitions. `array` is a vector created by `asn1_parser2array()`.

#### Parameters

array | specify the array that contains ASN.1 declarations |
definitions | return the pointer to the structure created by *ARRAY ASN.1 declarations |
errorDescription | return the error description. |

#### Returns

`ASN1_SUCCESS` if structure was created correctly, `ASN1_ELEMENT_NOT_EMPTY` if *`definitions` not NULL, `ASN1_IDENTIFIER_NOT_FOUND` if in the file there is an identifier that is not defined (see `errorDescription` for more information), `ASN1_ARRAY_ERROR` if the array pointed by `array` is wrong.

### asn1_print_structure ()

    void
    asn1_print_structure (FILE *out,
                          asn1_node structure,
                          const char *name,
                          int mode);

Prints on the `out` file descriptor the structure's tree starting from the `name` element inside the structure `structure` .

#### Parameters

out | pointer to the output file (e.g. stdout). |
structure | pointer to the structure that you want to visit. |
name | an element of the structure |
mode | specify how much of the structure to print, can be `ASN1_PRINT_NAME`, `ASN1_PRINT_NAME_TYPE`, `ASN1_PRINT_NAME_TYPE_VALUE`, or `ASN1_PRINT_ALL`. |

### asn1_create_element ()

    int
    asn1_create_element (asn1_node definitions,
                         const char *source_name,
                         asn1_node *element);

Creates a structure of type `source_name` . Example using "pkix.asn":

rc = asn1_create_element(cert_def, "PKIX1.Certificate", certptr);

#### Parameters

definitions | pointer to the structure returned by "parser_asn1" function |
source_name | the name of the type of the new structure (must be inside p_structure). |
element | pointer to the structure created. |

#### Returns

`ASN1_SUCCESS` if creation OK, `ASN1_ELEMENT_NOT_FOUND` if `source_name` is not known.

### asn1_delete_structure ()

    int
    asn1_delete_structure (asn1_node *structure);

Deletes the structure *`structure` . At the end, *`structure` is set to NULL.

#### Parameters

structure | pointer to the structure that you want to delete. |

#### Returns

`ASN1_SUCCESS` if successful, `ASN1_ELEMENT_NOT_FOUND` if *`structure` was NULL.

### asn1_delete_structure2 ()

    int
    asn1_delete_structure2 (asn1_node *structure,
                            unsigned int flags);

Deletes the structure *`structure` . At the end, *`structure` is set to NULL.

#### Parameters

structure | pointer to the structure that you want to delete. |
flags | additional flags (see `ASN1_DELETE_FLAG`) |

#### Returns

`ASN1_SUCCESS` if successful, `ASN1_ELEMENT_NOT_FOUND` if *`structure` was NULL.

### asn1_delete_element ()

    int
    asn1_delete_element (asn1_node structure,
                         const char *element_name);

Deletes the element named *`element_name` inside *`structure` .

#### Parameters

structure | pointer to the structure that contains the element you want to delete. |
element_name | element's name you want to delete. |

#### Returns

`ASN1_SUCCESS` if successful, `ASN1_ELEMENT_NOT_FOUND` if the `element_name` was not found.

### asn1_write_value ()

    int
    asn1_write_value (asn1_node node_root,
                      const char *name,
                      const void *ivalue,
                      int len);

Set the value of one element inside a structure.

If an element is OPTIONAL and you want to delete it, you must use the value=NULL and len=0. Using "pkix.asn":

result=asn1_write_value(cert, "tbsCertificate.issuerUniqueID", NULL, 0);

Description for each type:

INTEGER: VALUE must contain a two's complement form integer.

value[0]=0xFF , len=1 -> integer=-1. value[0]=0xFF value[1]=0xFF , len=2 -> integer=-1. value[0]=0x01 , len=1 -> integer= 1. value[0]=0x00 value[1]=0x01 , len=2 -> integer= 1. value="123" , len=0 -> integer= 123.

ENUMERATED: As INTEGER (but only with not negative numbers).

BOOLEAN: VALUE must be the null terminated string "TRUE" or "FALSE" and LEN != 0.

value="TRUE" , len=1 -> boolean=TRUE. value="FALSE" , len=1 -> boolean=FALSE.

OBJECT IDENTIFIER: VALUE must be a null terminated string with each number separated by a dot (e.g. "1.2.3.543.1"). LEN != 0.

value="1 2 840 10040 4 3" , len=1 -> OID=dsa-with-sha.

UTCTime: VALUE must be a null terminated string in one of these formats: "YYMMDDhhmmssZ", "YYMMDDhhmmssZ", "YYMMDDhhmmss+hh'mm'", "YYMMDDhhmmss-hh'mm'", "YYMMDDhhmm+hh'mm'", or "YYMMDDhhmm-hh'mm'". LEN != 0.

value="9801011200Z" , len=1 -> time=Jannuary 1st, 1998 at 12h 00m Greenwich Mean Time

GeneralizedTime: VALUE must be in one of this format: "YYYYMMDDhhmmss.sZ", "YYYYMMDDhhmmss.sZ", "YYYYMMDDhhmmss.s+hh'mm'", "YYYYMMDDhhmmss.s-hh'mm'", "YYYYMMDDhhmm+hh'mm'", or "YYYYMMDDhhmm-hh'mm'" where ss.s indicates the seconds with any precision like "10.1" or "01.02". LEN != 0

value="2001010112001.12-0700" , len=1 -> time=Jannuary 1st, 2001 at 12h 00m 01.12s Pacific Daylight Time

OCTET STRING: VALUE contains the octet string and LEN is the number of octets.

value="$\backslash$x01$\backslash$x02$\backslash$x03" , len=3 -> three bytes octet string

GeneralString: VALUE contains the generalstring and LEN is the number of octets.

value="$\backslash$x01$\backslash$x02$\backslash$x03" , len=3 -> three bytes generalstring

BIT STRING: VALUE contains the bit string organized by bytes and LEN is the number of bits.

value="$\backslash$xCF" , len=6 -> bit string="110011" (six bits)

CHOICE: if NAME indicates a choice type, VALUE must specify one of the alternatives with a null terminated string. LEN != 0. Using "pkix.asn"\:

result=asn1_write_value(cert, "certificate1.tbsCertificate.subject", "rdnSequence", 1);

ANY: VALUE indicates the der encoding of a structure. LEN != 0.

SEQUENCE OF: VALUE must be the null terminated string "NEW" and LEN != 0. With this instruction another element is appended in the sequence. The name of this element will be "?1" if it's the first one, "?2" for the second and so on.

Using "pkix.asn"\:

result=asn1_write_value(cert, "certificate1.tbsCertificate.subject.rdnSequence", "NEW", 1);

SET OF: the same as SEQUENCE OF. Using "pkix.asn":

result=asn1_write_value(cert, "tbsCertificate.subject.rdnSequence.?LAST", "NEW", 1);

#### Parameters

node_root | pointer to a structure |
name | the name of the element inside the structure that you want to set. |
ivalue | vector used to specify the value to set. If len is >0, VALUE must be a two's complement form integer. if len=0 *VALUE must be a null terminated string with an integer value. |
len | number of bytes of *value to use to set the value: value[0]..value[len-1] or 0 if value is a null terminated string |

#### Returns

`ASN1_SUCCESS` if the value was set, `ASN1_ELEMENT_NOT_FOUND` if `name` is not a valid element, and `ASN1_VALUE_NOT_VALID` if `ivalue` has a wrong format.

### asn1_read_value ()

    int
    asn1_read_value (asn1_node root,
                     const char *name,
                     void *ivalue,
                     int *len);

Returns the value of one element inside a structure. If an element is OPTIONAL and this returns `ASN1_ELEMENT_NOT_FOUND`, it means that this element wasn't present in the der encoding that created the structure. The first element of a SEQUENCE_OF or SET_OF is named "?1". The second one "?2" and so on. If the `root` provided is a node to specific sequence element, then the keyword "?CURRENT" is also acceptable and indicates the current sequence element of this node.

Note that there can be valid values with length zero. In these case this function will succeed and `len` will be zero.

INTEGER: VALUE will contain a two's complement form integer.

integer=-1 -> value[0]=0xFF , len=1. integer=1 -> value[0]=0x01 , len=1.

ENUMERATED: As INTEGER (but only with not negative numbers).

BOOLEAN: VALUE will be the null terminated string "TRUE" or "FALSE" and LEN=5 or LEN=6.

OBJECT IDENTIFIER: VALUE will be a null terminated string with each number separated by a dot (i.e. "1.2.3.543.1").

LEN = strlen(VALUE)+1

UTCTime: VALUE will be a null terminated string in one of these formats: "YYMMDDhhmmss+hh'mm'" or "YYMMDDhhmmss-hh'mm'". LEN=strlen(VALUE)+1.

GeneralizedTime: VALUE will be a null terminated string in the same format used to set the value.

OCTET STRING: VALUE will contain the octet string and LEN will be the number of octets.

GeneralString: VALUE will contain the generalstring and LEN will be the number of octets.

BIT STRING: VALUE will contain the bit string organized by bytes and LEN will be the number of bits.

CHOICE: If NAME indicates a choice type, VALUE will specify the alternative selected.

ANY: If NAME indicates an any type, VALUE will indicate the DER encoding of the structure actually used.

#### Parameters

root | pointer to a structure. |
name | the name of the element inside a structure that you want to read. |
ivalue | vector that will contain the element's content, must be a pointer to memory cells already allocated (may be `NULL`). |
len | number of bytes of *value: value[0]..value[len-1]. Initialy holds the sizeof value. |

#### Returns

`ASN1_SUCCESS` if value is returned, `ASN1_ELEMENT_NOT_FOUND` if `name` is not a valid element, `ASN1_VALUE_NOT_FOUND` if there isn't any value for the element selected, and `ASN1_MEM_ERROR` if The value vector isn't big enough to store the result, and in this case `len` will contain the number of bytes needed.

### asn1_read_value_type ()

    int
    asn1_read_value_type (asn1_node root,
                          const char *name,
                          void *ivalue,
                          int *len,
                          unsigned int *etype);

Returns the type and value of one element inside a structure. If an element is OPTIONAL and this returns `ASN1_ELEMENT_NOT_FOUND`, it means that this element wasn't present in the der encoding that created the structure. The first element of a SEQUENCE_OF or SET_OF is named "?1". The second one "?2" and so on. If the `root` provided is a node to specific sequence element, then the keyword "?CURRENT" is also acceptable and indicates the current sequence element of this node.

Note that there can be valid values with length zero. In these case this function will succeed and `len` will be zero.

INTEGER: VALUE will contain a two's complement form integer.

integer=-1 -> value[0]=0xFF , len=1. integer=1 -> value[0]=0x01 , len=1.

ENUMERATED: As INTEGER (but only with not negative numbers).

BOOLEAN: VALUE will be the null terminated string "TRUE" or "FALSE" and LEN=5 or LEN=6.

OBJECT IDENTIFIER: VALUE will be a null terminated string with each number separated by a dot (i.e. "1.2.3.543.1").

LEN = strlen(VALUE)+1

UTCTime: VALUE will be a null terminated string in one of these formats: "YYMMDDhhmmss+hh'mm'" or "YYMMDDhhmmss-hh'mm'". LEN=strlen(VALUE)+1.

GeneralizedTime: VALUE will be a null terminated string in the same format used to set the value.

OCTET STRING: VALUE will contain the octet string and LEN will be the number of octets.

GeneralString: VALUE will contain the generalstring and LEN will be the number of octets.

BIT STRING: VALUE will contain the bit string organized by bytes and LEN will be the number of bits.

CHOICE: If NAME indicates a choice type, VALUE will specify the alternative selected.

ANY: If NAME indicates an any type, VALUE will indicate the DER encoding of the structure actually used.

#### Parameters

root | pointer to a structure. |
name | the name of the element inside a structure that you want to read. |
ivalue | vector that will contain the element's content, must be a pointer to memory cells already allocated (may be `NULL`). |
len | number of bytes of *value: value[0]..value[len-1]. Initialy holds the sizeof value. |
etype | The type of the value read (ASN1_ETYPE) |

#### Returns

`ASN1_SUCCESS` if value is returned, `ASN1_ELEMENT_NOT_FOUND` if `name` is not a valid element, `ASN1_VALUE_NOT_FOUND` if there isn't any value for the element selected, and `ASN1_MEM_ERROR` if The value vector isn't big enough to store the result, and in this case `len` will contain the number of bytes needed.

### asn1_read_node_value ()

    int
    asn1_read_node_value (asn1_node node,
                          asn1_data_node_st *data);

Returns the value a data node inside a asn1_node structure. The data returned should be handled as constant values.

#### Parameters

node | pointer to a node. |
data | a point to a asn1_data_node_st |

#### Returns

`ASN1_SUCCESS` if the node exists.

### asn1_number_of_elements ()

    int
    asn1_number_of_elements (asn1_node element,
                             const char *name,
                             int *num);

Counts the number of elements of a sub-structure called NAME with names equal to "?1","?2", ...

#### Parameters

element | pointer to the root of an ASN1 structure. |
name | the name of a sub-structure of ROOT. |
num | pointer to an integer where the result will be stored |

#### Returns

`ASN1_SUCCESS` if successful, `ASN1_ELEMENT_NOT_FOUND` if `name` is not known, `ASN1_GENERIC_ERROR` if pointer `num` is `NULL`.

### asn1_der_coding ()

    int
    asn1_der_coding (asn1_node element,
                     const char *name,
                     void *ider,
                     int *len,
                     char *ErrorDescription);

Creates the DER encoding for the NAME structure (inside *POINTER structure).

#### Parameters

element | pointer to an ASN1 element |
name | the name of the structure you want to encode (it must be inside *POINTER). |
ider | vector that will contain the DER encoding. DER must be a pointer to memory cells already allocated. |
len | number of bytes of *`ider` : `ider` [0]..`ider` [len-1], Initialy holds the sizeof of der vector. |
ErrorDescription | return the error description or an empty string if success. |

#### Returns

`ASN1_SUCCESS` if DER encoding OK, `ASN1_ELEMENT_NOT_FOUND` if `name` is not a valid element, `ASN1_VALUE_NOT_FOUND` if there is an element without a value, `ASN1_MEM_ERROR` if the `ider` vector isn't big enough and in this case `len` will contain the length needed.

### asn1_der_decoding2 ()

    int
    asn1_der_decoding2 (asn1_node *element,
                        const void *ider,
                        int *max_ider_len,
                        unsigned int flags,
                        char *errorDescription);

Fill the structure *`element` with values of a DER encoding string. The structure must just be created with function `asn1_create_element()`.

If `ASN1_DECODE_FLAG_ALLOW_PADDING` flag is set then the function will ignore padding after the decoded DER data. Upon a successful return the value of *`max_ider_len` will be set to the number of bytes decoded.

If `ASN1_DECODE_FLAG_STRICT_DER` flag is set then the function will not decode any BER-encoded elements.

#### Parameters

element | pointer to an ASN1 structure. |
ider | vector that contains the DER encoding. |
max_ider_len | pointer to an integer giving the information about the maximal number of bytes occupied by *`ider` . The real size of the DER encoding is returned through this pointer. |
flags | flags controlling the behaviour of the function. |
errorDescription | null-terminated string contains details when an error occurred. |

#### Returns

`ASN1_SUCCESS` if DER encoding OK, `ASN1_ELEMENT_NOT_FOUND` if `ELEMENT` is `NULL`, and `ASN1_TAG_ERROR` or `ASN1_DER_ERROR` if the der encoding doesn't match the structure name (*`ELEMENT` deleted).

### asn1_der_decoding ()

    int
    asn1_der_decoding (asn1_node *element,
                       const void *ider,
                       int len,
                       char *errorDescription);

Fill the structure *`element` with values of a DER encoding string. The structure must just be created with function `asn1_create_element()`.

Note that the *`element` variable is provided as a pointer for historical reasons.

#### Parameters

element | pointer to an ASN1 structure. |
ider | vector that contains the DER encoding. |
errorDescription | null-terminated string contains details when an error occurred. |

#### Returns

`ASN1_SUCCESS` if DER encoding OK, `ASN1_ELEMENT_NOT_FOUND` if `ELEMENT` is `NULL`, and `ASN1_TAG_ERROR` or `ASN1_DER_ERROR` if the der encoding doesn't match the structure name (*`ELEMENT` deleted).

### asn1_der_decoding_element ()

    int
    asn1_der_decoding_element (asn1_node *structure,
                               const char *elementName,
                               const void *ider,
                               int len,
                               char *errorDescription);

`asn1_der_decoding_element` is deprecated and should not be used in newly-written code.

Fill the element named `ELEMENTNAME` with values of a DER encoding string. The structure must just be created with function `asn1_create_element()`. The DER vector must contain the encoding string of the whole `STRUCTURE` . If an error occurs during the decoding procedure, the *`STRUCTURE` is deleted and set equal to `NULL`.

This function is deprecated and may just be an alias to asn1_der_decoding in future versions. Use `asn1_der_decoding()` instead.

#### Parameters

structure | pointer to an ASN1 structure |
elementName | name of the element to fill |
ider | vector that contains the DER encoding of the whole structure. |
len | number of bytes of *der: der[0]..der[len-1] |
errorDescription | null-terminated string contains details when an error occurred. |

#### Returns

`ASN1_SUCCESS` if DER encoding OK, `ASN1_ELEMENT_NOT_FOUND` if ELEMENT is `NULL` or `elementName` == NULL, and `ASN1_TAG_ERROR` or `ASN1_DER_ERROR` if the der encoding doesn't match the structure `structure` (*ELEMENT deleted).

### asn1_der_decoding_startEnd ()

    int
    asn1_der_decoding_startEnd (asn1_node element,
                                const void *ider,
                                int len,
                                const char *name_element,
                                int *start,
                                int *end);

Find the start and end point of an element in a DER encoding string. I mean that if you have a der encoding and you have already used the function `asn1_der_decoding()` to fill a structure, it may happen that you want to find the piece of string concerning an element of the structure.

One example is the sequence "tbsCertificate" inside an X509 certificate.

Note that since libtasn1 3.7 the `ider` and `ider_len` parameters can be omitted, if the element is already decoded using `asn1_der_decoding()`.

#### Parameters

element | pointer to an ASN1 element |
ider | vector that contains the DER encoding. |
name_element | an element of NAME structure. |
start | the position of the first byte of NAME_ELEMENT decoding (`ider` [*start]) |
end | the position of the last byte of NAME_ELEMENT decoding (`ider` [*end]) |

#### Returns

`ASN1_SUCCESS` if DER encoding OK, `ASN1_ELEMENT_NOT_FOUND` if ELEMENT is `asn1_node` EMPTY or `name_element` is not a valid element, `ASN1_TAG_ERROR` or `ASN1_DER_ERROR` if the der encoding doesn't match the structure ELEMENT.

### asn1_expand_any_defined_by ()

    int
    asn1_expand_any_defined_by (asn1_node definitions,
                                asn1_node *element);

Expands every "ANY DEFINED BY" element of a structure created from a DER decoding process (asn1_der_decoding function). The element ANY must be defined by an OBJECT IDENTIFIER. The type used to expand the element ANY is the first one following the definition of the actual value of the OBJECT IDENTIFIER.

#### Parameters

definitions | ASN1 definitions |
element | pointer to an ASN1 structure |

#### Returns

`ASN1_SUCCESS` if Substitution OK, `ASN1_ERROR_TYPE_ANY` if some "ANY DEFINED BY" element couldn't be expanded due to a problem in OBJECT_ID -> TYPE association, or other error codes depending on DER decoding.

### asn1_expand_octet_string ()

    int
    asn1_expand_octet_string (asn1_node definitions,
                              asn1_node *element,
                              const char *octetName,
                              const char *objectName);

Expands an "OCTET STRING" element of a structure created from a DER decoding process (the `asn1_der_decoding()` function). The type used for expansion is the first one following the definition of the actual value of the OBJECT IDENTIFIER indicated by OBJECTNAME.

#### Parameters

definitions | ASN1 definitions |
element | pointer to an ASN1 structure |
octetName | name of the OCTECT STRING field to expand. |
objectName | name of the OBJECT IDENTIFIER field to use to define the type for expansion. |

#### Returns

`ASN1_SUCCESS` if substitution OK, `ASN1_ELEMENT_NOT_FOUND` if `objectName` or `octetName` are not correct, `ASN1_VALUE_NOT_VALID` if it wasn't possible to find the type to use for expansion, or other errors depending on DER decoding.

### asn1_read_tag ()

    int
    asn1_read_tag (asn1_node root,
                   const char *name,
                   int *tagValue,
                   int *classValue);

Returns the TAG and the CLASS of one element inside a structure. CLASS can have one of these constants: `ASN1_CLASS_APPLICATION`, `ASN1_CLASS_UNIVERSAL`, `ASN1_CLASS_PRIVATE` or `ASN1_CLASS_CONTEXT_SPECIFIC`.

#### Parameters

root | pointer to a structure |
name | the name of the element inside a structure. |
tagValue | variable that will contain the TAG value. |
classValue | variable that will specify the TAG type. |

#### Returns

`ASN1_SUCCESS` if successful, `ASN1_ELEMENT_NOT_FOUND` if `name` is not a valid element.

### asn1_find_structure_from_oid ()

    const char *
    asn1_find_structure_from_oid (asn1_node definitions,
                                  const char *oidValue);

Search the structure that is defined just after an OID definition.

#### Parameters

definitions | ASN1 definitions |
oidValue | value of the OID to search (e.g. "1.2.3.4"). |

#### Returns

`NULL` when `oidValue` not found, otherwise the pointer to a constant string that contains the element name defined just after the OID.

### asn1_check_version ()

    const char *
    asn1_check_version (const char *req_version);

Check that the version of the library is at minimum the requested one and return the version string; return `NULL` if the condition is not satisfied. If a `NULL` is passed to this function, no check is done, but the version string is simply returned.

See `ASN1_VERSION` for a suitable `req_version` string.

#### Parameters

req_version | Required version number, or `NULL`. |

#### Returns

Version string of run-time library, or `NULL` if the run-time library does not meet the required version number.

### asn1_strerror ()

    const char *
    asn1_strerror (int error);

Returns a string with a description of an error. This function is similar to strerror. The only difference is that it accepts an error (number) returned by a libtasn1 function.

#### Parameters

error | is an error returned by a libtasn1 function. |

#### Returns

Pointer to static zero-terminated string describing error code.

Since 1.6

### asn1_perror ()

    void
    asn1_perror (int error);

Prints a string to stderr with a description of an error. This function is like `perror()`. The only difference is that it accepts an error returned by a libtasn1 function.

#### Parameters

error | is an error returned by a libtasn1 function. |

Since 1.6

### ASN1_MAX_TL_SIZE

    #define ASN1_MAX_TL_SIZE (ASN1_MAX_TAG_SIZE+ASN1_MAX_LENGTH_SIZE)

### asn1_get_length_der ()

    long
    asn1_get_length_der (const unsigned char *der,
                         int der_len,
                         int *len);

Extract a length field from DER data.

#### Parameters

der | DER data to decode. |
der_len | Length of DER data to decode. |
len | Output variable containing the length of the DER length field. |

#### Returns

Return the decoded length value, or -1 on indefinite length, or -2 when the value was too big to fit in a int, or -4 when the decoded length value plus `len` would exceed `der_len` .

### asn1_get_length_ber ()

    long
    asn1_get_length_ber (const unsigned char *ber,
                         int ber_len,
                         int *len);

Extract a length field from BER data. The difference to `asn1_get_length_der()` is that this function will return a length even if the value has indefinite encoding.

#### Parameters

ber | BER data to decode. |
ber_len | Length of BER data to decode. |
len | Output variable containing the length of the BER length field. |

#### Returns

Return the decoded length value, or negative value when the value was too big.

Since 2.0

### asn1_length_der ()

    void
    asn1_length_der (unsigned long int len,
                     unsigned char *der,
                     int *der_len);

Creates the DER encoding of the provided length value. The `der` buffer must have enough room for the output. The maximum length this function will encode is `ASN1_MAX_LENGTH_SIZE`.

To know the size of the DER encoding use a `NULL` value for `der` .

#### Parameters

len | value to convert. |
der | buffer to hold the returned encoding (may be `NULL`). |
der_len | number of meaningful bytes of ANS (der[0]..der[der_len-1]). |

### asn1_decode_simple_der ()

    int
    asn1_decode_simple_der (unsigned int etype,
                            const unsigned char *der,
                            unsigned int der_len,
                            const unsigned char **str,
                            unsigned int *str_len);

Decodes a simple DER encoded type (e.g. a string, which is not constructed). The output is a pointer inside the `der` .

#### Parameters

etype | The type of the string to be encoded (ASN1_ETYPE_) |
der | the encoded string |
der_len | the bytes of the encoded string |
str | a pointer to the data |
str_len | the length of the data |

#### Returns

`ASN1_SUCCESS` if successful or an error value.

### asn1_encode_simple_der ()

    int
    asn1_encode_simple_der (unsigned int etype,
                            const unsigned char *str,
                            unsigned int str_len,
                            unsigned char *tl,
                            unsigned int *tl_len);

Creates the DER encoding for various simple ASN.1 types like strings etc. It stores the tag and length in `tl` , which should have space for at least `ASN1_MAX_TL_SIZE` bytes. Initially `tl_len` should contain the size of `tl` .

The complete DER encoding should consist of the value in `tl` appended with the provided `str` .

#### Parameters

etype | The type of the string to be encoded (ASN1_ETYPE_) |
str | the string data. |
str_len | the string length |
tl | the encoded tag and length |
tl_len | the bytes of the `tl` field |

#### Returns

`ASN1_SUCCESS` if successful or an error value.

### asn1_find_node ()

    asn1_node
    asn1_find_node (asn1_node pointer,
                    const char *name);

Searches for an element called `name` starting from `pointer` . The name is composed by differents identifiers separated by dots. When *`pointer` has a name, the first identifier must be the name of *`pointer` , otherwise it must be the name of one child of *`pointer` .

#### Parameters

pointer | NODE_ASN element pointer. |
name | null terminated string with the element's name to find. |

#### Returns

the search result, or `NULL` if not found.

### asn1_copy_node ()

    int
    asn1_copy_node (asn1_node dst,
                    const char *dst_name,
                    asn1_node src,
                    const char *src_name);

Create a deep copy of a asn1_node variable. That function requires `dst` to be expanded using `asn1_create_element()`.

#### Parameters

dst | Destination asn1 node. |
dst_name | Field name in destination node. |
src | Source asn1 node. |
src_name | Field name in source node. |

#### Returns

Return `ASN1_SUCCESS` on success.

### asn1_dup_node ()

    asn1_node
    asn1_dup_node (asn1_node src,
                   const char *src_name);

Create a deep copy of a asn1_node variable. This function will return an exact copy of the provided structure.

#### Parameters

src | Source asn1 node. |
src_name | Field name in source node. |

#### Returns

Return `NULL` on failure.

### asn1_get_tag_der ()

    int
    asn1_get_tag_der (const unsigned char *der,
                      int der_len,
                      unsigned char *cls,
                      int *len,
                      unsigned long *tag);

Decode the class and TAG from DER code.

#### Parameters

der | DER data to decode. |
der_len | Length of DER data to decode. |
cls | Output variable containing decoded class. |
len | Output variable containing the length of the DER TAG data. |
tag | Output variable containing the decoded tag. |

#### Returns

Returns `ASN1_SUCCESS` on success, or an error.

### asn1_octet_der ()

    void
    asn1_octet_der (const unsigned char *str,
                    int str_len,
                    unsigned char *der,
                    int *der_len);

Creates a length-value DER encoding for the input data. The DER encoding of the input data will be placed in the `der` variable.

Note that the OCTET STRING tag is not included in the output.

This function does not return any value because it is expected that `der_len` will contain enough bytes to store the string plus the DER encoding. The DER encoding size can be obtained using `asn1_length_der()`.

#### Parameters

str | the input data. |
str_len | STR length (str[0]..str[*str_len-1]). |
der | encoded string returned. |
der_len | number of meaningful bytes of DER (der[0]..der[der_len-1]). |

### asn1_get_octet_der ()

    int
    asn1_get_octet_der (const unsigned char *der,
                        int der_len,
                        int *ret_len,
                        unsigned char *str,
                        int str_size,
                        int *str_len);

Extract an OCTET SEQUENCE from DER data.

#### Parameters

der | DER data to decode containing the OCTET SEQUENCE. |
der_len | Length of DER data to decode. |
ret_len | Output variable containing the length of the DER data. |
str | Pre-allocated output buffer to put decoded OCTET SEQUENCE in. |
str_size | Length of pre-allocated output buffer. |
str_len | Output variable containing the length of the OCTET SEQUENCE. |

#### Returns

Returns `ASN1_SUCCESS` on success, or an error.

### asn1_bit_der ()

    void
    asn1_bit_der (const unsigned char *str,
                  int bit_len,
                  unsigned char *der,
                  int *der_len);

Creates a length-value DER encoding for the input data as it would have been for a BIT STRING. The DER encoded data will be copied in `der` .

Note that the BIT STRING tag is not included in the output.

This function does not return any value because it is expected that `der_len` will contain enough bytes to store the string plus the DER encoding. The DER encoding size can be obtained using `asn1_length_der()`.

#### Parameters

str | BIT string. |
bit_len | number of meaningful bits in STR. |
der | string returned. |
der_len | number of meaningful bytes of DER (der[0]..der[ans_len-1]). |

### asn1_get_bit_der ()

    int
    asn1_get_bit_der (const unsigned char *der,
                      int der_len,
                      int *ret_len,
                      unsigned char *str,
                      int str_size,
                      int *bit_len);

Extract a BIT SEQUENCE from DER data.

#### Parameters

der | DER data to decode containing the BIT SEQUENCE. |
der_len | Length of DER data to decode. |
ret_len | Output variable containing the length of the DER data. |
str | Pre-allocated output buffer to put decoded BIT SEQUENCE in. |
str_size | Length of pre-allocated output buffer. |
bit_len | Output variable containing the size of the BIT SEQUENCE. |

#### Returns

Return `ASN1_SUCCESS` on success, or an error.

## Types and Values

### ASN1_API

    #define ASN1_API __attribute__((__visibility__("default")))

### ASN1_VERSION

    #define ASN1_VERSION "4.0"

### ASN1_SUCCESS

    #define ASN1_SUCCESS			0

### ASN1_FILE_NOT_FOUND

    #define ASN1_FILE_NOT_FOUND		1

### ASN1_ELEMENT_NOT_FOUND

    #define ASN1_ELEMENT_NOT_FOUND		2

### ASN1_IDENTIFIER_NOT_FOUND

    #define ASN1_IDENTIFIER_NOT_FOUND 3

### ASN1_DER_ERROR

    #define ASN1_DER_ERROR			4

### ASN1_VALUE_NOT_FOUND

    #define ASN1_VALUE_NOT_FOUND		5

### ASN1_GENERIC_ERROR

    #define ASN1_GENERIC_ERROR		6

### ASN1_VALUE_NOT_VALID

    #define ASN1_VALUE_NOT_VALID		7

### ASN1_TAG_ERROR

    #define ASN1_TAG_ERROR			8

### ASN1_TAG_IMPLICIT

    #define ASN1_TAG_IMPLICIT		9

### ASN1_ERROR_TYPE_ANY

    #define ASN1_ERROR_TYPE_ANY		10

### ASN1_SYNTAX_ERROR

    #define ASN1_SYNTAX_ERROR		11

### ASN1_MEM_ERROR

    #define ASN1_MEM_ERROR			12

### ASN1_MEM_ALLOC_ERROR

    #define ASN1_MEM_ALLOC_ERROR		13

### ASN1_DER_OVERFLOW

    #define ASN1_DER_OVERFLOW		14

### ASN1_NAME_TOO_LONG

    #define ASN1_NAME_TOO_LONG		15

### ASN1_ARRAY_ERROR

    #define ASN1_ARRAY_ERROR		16

### ASN1_ELEMENT_NOT_EMPTY

    #define ASN1_ELEMENT_NOT_EMPTY		17

### ASN1_PRINT_NAME

    #define ASN1_PRINT_NAME			1

### ASN1_PRINT_NAME_TYPE

    #define ASN1_PRINT_NAME_TYPE		2

### ASN1_PRINT_NAME_TYPE_VALUE

    #define ASN1_PRINT_NAME_TYPE_VALUE 3

### ASN1_PRINT_ALL

    #define ASN1_PRINT_ALL			4

### ASN1_CLASS_UNIVERSAL

    #define ASN1_CLASS_UNIVERSAL		0x00 /* old: 1 */

### ASN1_CLASS_APPLICATION

    #define ASN1_CLASS_APPLICATION		0x40 /* old: 2 */

### ASN1_CLASS_CONTEXT_SPECIFIC

    #define ASN1_CLASS_CONTEXT_SPECIFIC 0x80 /* old: 3 */

### ASN1_CLASS_PRIVATE

    #define ASN1_CLASS_PRIVATE		0xC0 /* old: 4 */

### ASN1_CLASS_STRUCTURED

    #define ASN1_CLASS_STRUCTURED		0x20

### ASN1_TAG_BOOLEAN

    #define ASN1_TAG_BOOLEAN		0x01

### ASN1_TAG_INTEGER

    #define ASN1_TAG_INTEGER		0x02

### ASN1_TAG_SEQUENCE

    #define ASN1_TAG_SEQUENCE		0x10

### ASN1_TAG_SET

    #define ASN1_TAG_SET			0x11

### ASN1_TAG_OCTET_STRING

    #define ASN1_TAG_OCTET_STRING		0x04

### ASN1_TAG_BIT_STRING

    #define ASN1_TAG_BIT_STRING		0x03

### ASN1_TAG_UTCTime

    #define ASN1_TAG_UTCTime		0x17

### ASN1_TAG_GENERALIZEDTime

    #define ASN1_TAG_GENERALIZEDTime 0x18

### ASN1_TAG_OBJECT_ID

    #define ASN1_TAG_OBJECT_ID		0x06

### ASN1_TAG_ENUMERATED

    #define ASN1_TAG_ENUMERATED		0x0A

### ASN1_TAG_NULL

    #define ASN1_TAG_NULL			0x05

### ASN1_TAG_GENERALSTRING

    #define ASN1_TAG_GENERALSTRING		0x1B

### ASN1_TAG_NUMERIC_STRING

    #define ASN1_TAG_NUMERIC_STRING		0x12

### ASN1_TAG_IA5_STRING

    #define ASN1_TAG_IA5_STRING		0x16

### ASN1_TAG_TELETEX_STRING

    #define ASN1_TAG_TELETEX_STRING		0x14

### ASN1_TAG_PRINTABLE_STRING

    #define ASN1_TAG_PRINTABLE_STRING 0x13

### ASN1_TAG_UNIVERSAL_STRING

    #define ASN1_TAG_UNIVERSAL_STRING 0x1C

### ASN1_TAG_BMP_STRING

    #define ASN1_TAG_BMP_STRING		0x1E

### ASN1_TAG_UTF8_STRING

    #define ASN1_TAG_UTF8_STRING		0x0C

### ASN1_TAG_VISIBLE_STRING

    #define ASN1_TAG_VISIBLE_STRING		0x1A

### asn1_node_st

      typedef struct asn1_node_st asn1_node_st;

### asn1_node

      typedef asn1_node_st *asn1_node;

### ASN1_MAX_NAME_SIZE

    #define ASN1_MAX_NAME_SIZE 64

### asn1_static_node

      typedef struct asn1_static_node_st asn1_static_node;

### ASN1_ETYPE_INVALID

    #define ASN1_ETYPE_INVALID        0

### ASN1_ETYPE_CONSTANT

    #define ASN1_ETYPE_CONSTANT       1

### ASN1_ETYPE_IDENTIFIER

    #define ASN1_ETYPE_IDENTIFIER     2

### ASN1_ETYPE_INTEGER

    #define ASN1_ETYPE_INTEGER        3

### ASN1_ETYPE_BOOLEAN

    #define ASN1_ETYPE_BOOLEAN        4

### ASN1_ETYPE_SEQUENCE

    #define ASN1_ETYPE_SEQUENCE       5

### ASN1_ETYPE_BIT_STRING

    #define ASN1_ETYPE_BIT_STRING     6

### ASN1_ETYPE_OCTET_STRING

    #define ASN1_ETYPE_OCTET_STRING   7

### ASN1_ETYPE_TAG

    #define ASN1_ETYPE_TAG            8

### ASN1_ETYPE_DEFAULT

    #define ASN1_ETYPE_DEFAULT        9

### ASN1_ETYPE_SIZE

    #define ASN1_ETYPE_SIZE          10

### ASN1_ETYPE_SEQUENCE_OF

    #define ASN1_ETYPE_SEQUENCE_OF   11

### ASN1_ETYPE_OBJECT_ID

    #define ASN1_ETYPE_OBJECT_ID     12

### ASN1_ETYPE_ANY

    #define ASN1_ETYPE_ANY           13

### ASN1_ETYPE_SET

    #define ASN1_ETYPE_SET           14

### ASN1_ETYPE_SET_OF

    #define ASN1_ETYPE_SET_OF        15

### ASN1_ETYPE_DEFINITIONS

    #define ASN1_ETYPE_DEFINITIONS   16

### ASN1_ETYPE_CHOICE

    #define ASN1_ETYPE_CHOICE        18

### ASN1_ETYPE_IMPORTS

    #define ASN1_ETYPE_IMPORTS       19

### ASN1_ETYPE_NULL

    #define ASN1_ETYPE_NULL          20

### ASN1_ETYPE_ENUMERATED

    #define ASN1_ETYPE_ENUMERATED    21

### ASN1_ETYPE_GENERALSTRING

    #define ASN1_ETYPE_GENERALSTRING 27

### ASN1_ETYPE_NUMERIC_STRING

    #define ASN1_ETYPE_NUMERIC_STRING 28

### ASN1_ETYPE_IA5_STRING

    #define ASN1_ETYPE_IA5_STRING     29

### ASN1_ETYPE_TELETEX_STRING

    #define ASN1_ETYPE_TELETEX_STRING 30

### ASN1_ETYPE_PRINTABLE_STRING

    #define ASN1_ETYPE_PRINTABLE_STRING 31

### ASN1_ETYPE_UNIVERSAL_STRING

    #define ASN1_ETYPE_UNIVERSAL_STRING 32

### ASN1_ETYPE_BMP_STRING

    #define ASN1_ETYPE_BMP_STRING     33

### ASN1_ETYPE_UTF8_STRING

    #define ASN1_ETYPE_UTF8_STRING    34

### ASN1_ETYPE_VISIBLE_STRING

    #define ASN1_ETYPE_VISIBLE_STRING 35

### ASN1_ETYPE_UTC_TIME

    #define ASN1_ETYPE_UTC_TIME       36

### ASN1_ETYPE_GENERALIZED_TIME

    #define ASN1_ETYPE_GENERALIZED_TIME 37

### ASN1_DELETE_FLAG_ZEROIZE

    #define ASN1_DELETE_FLAG_ZEROIZE 1

### ASN1_DECODE_FLAG_ALLOW_PADDING

    #define ASN1_DECODE_FLAG_ALLOW_PADDING 1

### asn1_data_node_st

      typedef struct asn1_data_node_st asn1_data_node_st;

### ASN1_MAX_ERROR_DESCRIPTION_SIZE

    #define ASN1_MAX_ERROR_DESCRIPTION_SIZE 128

### ASN1_MAX_TAG_SIZE

    #define ASN1_MAX_TAG_SIZE 4

### ASN1_MAX_LENGTH_SIZE

    #define ASN1_MAX_LENGTH_SIZE 9

### asn1_retCode

      typedef int asn1_retCode; /* type returned by libtasn1 functions */

### node_asn_struct

    #define node_asn_struct asn1_node_st

### node_asn

    #define node_asn asn1_node_st

### ASN1_TYPE

    #define ASN1_TYPE asn1_node

### ASN1_TYPE_EMPTY

    #define ASN1_TYPE_EMPTY NULL

### static_struct_asn

    #define static_struct_asn asn1_static_node_st

### ASN1_ARRAY_TYPE

    #define ASN1_ARRAY_TYPE asn1_static_node

### asn1_static_node_t

    #define asn1_static_node_t asn1_static_node

### node_data_struct

    #define node_data_struct asn1_data_node_st

### ASN1_DATA_NODE

    #define ASN1_DATA_NODE asn1_data_node_st