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/*
 * Types for encoding/decoding of ASN.1 using BER/DER (Basic/Distinguished
 * Encoding Rules).
 *
 * $Id: secasn1t.h,v 1.9 2004/04/25 15:03:18 gerv%gerv.net Exp $
 */

#ifndef _SECASN1T_H_
#define _SECASN1T_H_

/*
** An array of these structures defines a BER/DER encoding for an object.
**
** The array usually starts with a dummy entry whose kind is SEC_ASN1_SEQUENCE;
** such an array is terminated with an entry where kind == 0.  (An array
** which consists of a single component does not require a second dummy
** entry -- the array is only searched as long as previous component(s)
** instruct it.)
*/
typedef struct sec_ASN1Template_struct {
    /*
    ** Kind of item being decoded/encoded, including tags and modifiers.
    */
    unsigned long kind;

    /*
    ** The value is the offset from the base of the structure to the
    ** field that holds the value being decoded/encoded.
    */
    unsigned long offset;

    /*
    ** When kind suggests it (SEC_ASN1_POINTER, SEC_ASN1_GROUP, SEC_ASN1_INLINE,
    ** or a component that is *not* a SEC_ASN1_UNIVERSAL), this points to
    ** a sub-template for nested encoding/decoding,
    ** OR, iff SEC_ASN1_DYNAMIC is set, then this is a pointer to a pointer
    ** to a function which will return the appropriate template when called
    ** at runtime.  NOTE! that explicit level of indirection, which is
    ** necessary because ANSI does not allow you to store a function
    ** pointer directly as a "void *" so we must store it separately and
    ** dereference it to get at the function pointer itself.
    */
    const void *sub;

    /*
    ** In the first element of a template array, the value is the size
    ** of the structure to allocate when this template is being referenced
    ** by another template via SEC_ASN1_POINTER or SEC_ASN1_GROUP.
    ** In all other cases, the value is ignored.
    */
    unsigned int size;
} SEC_ASN1Template;


/* default size used for allocation of encoding/decoding stuff */
/* XXX what is the best value here? */
#define SEC_ASN1_DEFAULT_ARENA_SIZE	(2048)

/*
** BER/DER values for ASN.1 identifier octets.
*/
#define SEC_ASN1_TAG_MASK		0xff

/*
 * BER/DER universal type tag numbers.
 * The values are defined by the X.208 standard; do not change them!
 * NOTE: if you add anything to this list, you must add code to secasn1d.c
 * to accept the tag, and probably also to secasn1e.c to encode it.
 * XXX It appears some have been added recently without being added to
 * the code; so need to go through the list now and double-check them all.
 * (Look especially at those added in revision 1.10.)
 */
#define SEC_ASN1_TAGNUM_MASK		0x1f
#define SEC_ASN1_BOOLEAN		0x01
#define SEC_ASN1_INTEGER		0x02
#define SEC_ASN1_BIT_STRING		0x03
#define SEC_ASN1_OCTET_STRING		0x04
#define SEC_ASN1_NULL			0x05
#define SEC_ASN1_OBJECT_ID		0x06
#define SEC_ASN1_OBJECT_DESCRIPTOR      0x07
/* External type and instance-of type   0x08 */
#define SEC_ASN1_REAL                   0x09
#define SEC_ASN1_ENUMERATED		0x0a
#define SEC_ASN1_EMBEDDED_PDV           0x0b
#define SEC_ASN1_UTF8_STRING		0x0c
/*                                      0x0d */
/*                                      0x0e */
/*                                      0x0f */
#define SEC_ASN1_SEQUENCE		0x10
#define SEC_ASN1_SET			0x11
#define SEC_ASN1_NUMERIC_STRING         0x12
#define SEC_ASN1_PRINTABLE_STRING	0x13
#define SEC_ASN1_T61_STRING		0x14
#define SEC_ASN1_VIDEOTEX_STRING        0x15
#define SEC_ASN1_IA5_STRING		0x16
#define SEC_ASN1_UTC_TIME		0x17
#define SEC_ASN1_GENERALIZED_TIME	0x18
#define SEC_ASN1_GRAPHIC_STRING         0x19
#define SEC_ASN1_VISIBLE_STRING		0x1a
#define SEC_ASN1_GENERAL_STRING         0x1b
#define SEC_ASN1_UNIVERSAL_STRING	0x1c
/*                                      0x1d */
#define SEC_ASN1_BMP_STRING		0x1e
#define SEC_ASN1_HIGH_TAG_NUMBER	0x1f
#define SEC_ASN1_TELETEX_STRING 	SEC_ASN1_T61_STRING

/*
** Modifiers to type tags.  These are also specified by a/the
** standard, and must not be changed.
*/

#define SEC_ASN1_METHOD_MASK		0x20
#define SEC_ASN1_PRIMITIVE		0x00
#define SEC_ASN1_CONSTRUCTED		0x20

#define SEC_ASN1_CLASS_MASK		0xc0
#define SEC_ASN1_UNIVERSAL		0x00
#define SEC_ASN1_APPLICATION		0x40
#define SEC_ASN1_CONTEXT_SPECIFIC	0x80
#define SEC_ASN1_PRIVATE		0xc0

/*
** Our additions, used for templates.
** These are not defined by any standard; the values are used internally only.
** Just be careful to keep them out of the low 8 bits.
** XXX finish comments
*/
#define SEC_ASN1_OPTIONAL	0x00100
#define SEC_ASN1_EXPLICIT	0x00200
#define SEC_ASN1_ANY		0x00400
#define SEC_ASN1_INLINE		0x00800
#define SEC_ASN1_POINTER	0x01000
#define SEC_ASN1_GROUP		0x02000	/* with SET or SEQUENCE means
					 * SET OF or SEQUENCE OF */
#define SEC_ASN1_DYNAMIC	0x04000 /* subtemplate is found by calling
					 * a function at runtime */
#define SEC_ASN1_SKIP		0x08000 /* skip a field; only for decoding */
#define SEC_ASN1_INNER		0x10000	/* with ANY means capture the
					 * contents only (not the id, len,
					 * or eoc); only for decoding */
#define SEC_ASN1_SAVE		0x20000 /* stash away the encoded bytes first;
					 * only for decoding */
#define SEC_ASN1_MAY_STREAM	0x40000	/* field or one of its sub-fields may
					 * stream in and so should encode as
					 * indefinite-length when streaming
					 * has been indicated; only for
					 * encoding */
#define SEC_ASN1_SKIP_REST	0x80000	/* skip all following fields;
					   only for decoding */
#define SEC_ASN1_CHOICE        0x100000 /* pick one from a template */
#define SEC_ASN1_NO_STREAM     0X200000 /* This entry will not stream
                                           even if the sub-template says
                                           streaming is possible.  Helps
                                           to solve ambiguities with potential
                                           streaming entries that are 
                                           optional */
#define SEC_ASN1_DEBUG_BREAK   0X400000 /* put this in your template and the
                                           decoder will assert when it
                                           processes it. Only for use with
                                           SEC_QuickDERDecodeItem */

                                          

/* Shorthand/Aliases */
#define SEC_ASN1_SEQUENCE_OF	(SEC_ASN1_GROUP | SEC_ASN1_SEQUENCE)
#define SEC_ASN1_SET_OF		(SEC_ASN1_GROUP | SEC_ASN1_SET)
#define SEC_ASN1_ANY_CONTENTS	(SEC_ASN1_ANY | SEC_ASN1_INNER)

/* Maximum depth of nested SEQUENCEs and SETs */
#define SEC_ASN1D_MAX_DEPTH 32

/*
** Function used for SEC_ASN1_DYNAMIC.
** "arg" is a pointer to the structure being encoded/decoded
** "enc", when true, means that we are encoding (false means decoding)
*/
typedef const SEC_ASN1Template * SEC_ASN1TemplateChooser(void *arg, PRBool enc);
typedef SEC_ASN1TemplateChooser * SEC_ASN1TemplateChooserPtr;

#if defined(_WIN32)
#define SEC_ASN1_GET(x)        NSS_Get_##x(NULL, PR_FALSE)
#define SEC_ASN1_SUB(x)        &p_NSS_Get_##x
#define SEC_ASN1_XTRN          SEC_ASN1_DYNAMIC
#define SEC_ASN1_MKSUB(x) \
static const SEC_ASN1TemplateChooserPtr p_NSS_Get_##x = &NSS_Get_##x;
#else
#define SEC_ASN1_GET(x)        x
#define SEC_ASN1_SUB(x)        x
#define SEC_ASN1_XTRN          0
#define SEC_ASN1_MKSUB(x) 
#endif

#define SEC_ASN1_CHOOSER_DECLARE(x) \
extern const SEC_ASN1Template * NSS_Get_##x (void *arg, PRBool enc);

#define SEC_ASN1_CHOOSER_IMPLEMENT(x) \
const SEC_ASN1Template * NSS_Get_##x(void * arg, PRBool enc) \
{ return x; }

/*
** Opaque object used by the decoder to store state.
*/
typedef struct sec_DecoderContext_struct SEC_ASN1DecoderContext;

/*
** Opaque object used by the encoder to store state.
*/
typedef struct sec_EncoderContext_struct SEC_ASN1EncoderContext;

/*
 * This is used to describe to a filter function the bytes that are
 * being passed to it.  This is only useful when the filter is an "outer"
 * one, meaning it expects to get *all* of the bytes not just the
 * contents octets.
 */
typedef enum {
    SEC_ASN1_Identifier = 0,
    SEC_ASN1_Length = 1,
    SEC_ASN1_Contents = 2,
    SEC_ASN1_EndOfContents = 3
} SEC_ASN1EncodingPart;

/*
 * Type of the function pointer used either for decoding or encoding,
 * when doing anything "funny" (e.g. manipulating the data stream)
 */ 
typedef void (* SEC_ASN1NotifyProc)(void *arg, PRBool before,
				    void *dest, int real_depth);

/*
 * Type of the function pointer used for grabbing encoded bytes.
 * This can be used during either encoding or decoding, as follows...
 *
 * When decoding, this can be used to filter the encoded bytes as they
 * are parsed.  This is what you would do if you wanted to process the data
 * along the way (like to decrypt it, or to perform a hash on it in order
 * to do a signature check later).  See SEC_ASN1DecoderSetFilterProc().
 * When processing only part of the encoded bytes is desired, you "watch"
 * for the field(s) you are interested in with a "notify proc" (see
 * SEC_ASN1DecoderSetNotifyProc()) and for even finer granularity (e.g. to
 * ignore all by the contents bytes) you pay attention to the "data_kind"
 * parameter.
 *
 * When encoding, this is the specification for the output function which
 * will receive the bytes as they are encoded.  The output function can
 * perform any postprocessing necessary (like hashing (some of) the data
 * to create a digest that gets included at the end) as well as shoving
 * the data off wherever it needs to go.  (In order to "tune" any processing,
 * you can set a "notify proc" as described above in the decoding case.)
 *
 * The parameters:
 * - "arg" is an opaque pointer that you provided at the same time you
 *   specified a function of this type
 * - "data" is a buffer of length "len", containing the encoded bytes
 * - "depth" is how deep in a nested encoding we are (it is not usually
 *   valuable, but can be useful sometimes so I included it)
 * - "data_kind" tells you if these bytes are part of the ASN.1 encoded
 *   octets for identifier, length, contents, or end-of-contents
 */ 
typedef void (* SEC_ASN1WriteProc)(void *arg,
				   const char *data, unsigned long len,
				   int depth, SEC_ASN1EncodingPart data_kind);

#endif /* _SECASN1T_H_ */
