/* Simple ASN.1 parser
 * Copyright (C) 2000-2004 Andreas Steffen, Zuercher Hochschule Winterthur
 * Copyright (C) 2005 Michael Richardson <mcr@marajade.sandelman.ca>
 * Copyright (C) 2009 Paul Wouters <paul@xelerance.com>
 * Copyright (C) 2013 D. Hugh Redelmeier <hugh@mimosa.com>
 * Copyright (C) 2013 Paul Wouters <pwouters@redhat.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * for more details.
 *
 */

/* Defines some primitive ASN1 types */

typedef enum {
	ASN1_EOC =                  0x00,
	ASN1_BOOLEAN =              0x01,
	ASN1_INTEGER =              0x02,
	ASN1_BIT_STRING =           0x03,
	ASN1_OCTET_STRING =         0x04,
	ASN1_NULL =                 0x05,
	ASN1_OID =                  0x06,
	ASN1_ENUMERATED =           0x0A,
	ASN1_UTF8STRING =           0x0C,
	ASN1_NUMERICSTRING =        0x12,
	ASN1_PRINTABLESTRING =      0x13,
	ASN1_T61STRING =            0x14,
	ASN1_VIDEOTEXSTRING =       0x15,
	ASN1_IA5STRING =            0x16,
	ASN1_UTCTIME =              0x17,
	ASN1_GENERALIZEDTIME =      0x18,
	ASN1_GRAPHICSTRING =        0x19,
	ASN1_VISIBLESTRING =        0x1A,
	ASN1_GENERALSTRING =        0x1B,
	ASN1_UNIVERSALSTRING =      0x1C,
	ASN1_BMPSTRING =            0x1E,

	ASN1_CONSTRUCTED =          0x20,

	ASN1_SEQUENCE =             0x30,

	ASN1_SET =                  0x31,

	ASN1_CONTEXT_S_0 =          0x80,
	ASN1_CONTEXT_S_1 =          0x81,
	ASN1_CONTEXT_S_2 =          0x82,
	ASN1_CONTEXT_S_3 =          0x83,
	ASN1_CONTEXT_S_4 =          0x84,
	ASN1_CONTEXT_S_5 =          0x85,
	ASN1_CONTEXT_S_6 =          0x86,
	ASN1_CONTEXT_S_7 =          0x87,
	ASN1_CONTEXT_S_8 =          0x88,

	ASN1_CONTEXT_C_0 =          0xA0,
	ASN1_CONTEXT_C_1 =          0xA1,
	ASN1_CONTEXT_C_2 =          0xA2,
	ASN1_CONTEXT_C_3 =          0xA3,
	ASN1_CONTEXT_C_4 =          0xA4,
	ASN1_CONTEXT_C_5 =          0xA5
} asn1_t;

/* Definition of ASN1 flags */

#define ASN1_NONE       0x00
#define ASN1_DEF        0x01
#define ASN1_OPT        0x02
#define ASN1_LOOP       0x04
#define ASN1_END        0x08
#define ASN1_OBJ        0x10
#define ASN1_BODY       0x20
#define ASN1_RAW        0x40

#define ASN1_INVALID_LENGTH     (~(size_t) 0)   /* largest size_t */

#define ASN1_MAX_LEN    (1U << (8 * 3))         /* don't handle objects with length greater than this */
#define ASN1_MAX_LEN_LEN    4                   /* no coded length takes more than 4 bytes. */

/* definition of an ASN.1 object */

typedef struct {
	u_int level;
	const char  *name;
	asn1_t type;
	u_char flags;
} asn1Object_t;

#define ASN1_MAX_LEVEL  10

typedef struct {
	bool implicit;
	u_int cond;
	u_int level0;
	u_int loopAddr[ASN1_MAX_LEVEL + 1];
	chunk_t blobs[ASN1_MAX_LEVEL + 2];
} asn1_ctx_t;

extern int known_oid(chunk_t object);
extern size_t asn1_length(chunk_t *blob);
extern void code_asn1_length(size_t length, chunk_t *code);
extern u_char *build_asn1_object(chunk_t *object, asn1_t type, size_t datalen);
extern u_char *build_asn1_explicit_object(chunk_t *object, asn1_t outer_type,
					  asn1_t inner_type, size_t datalen);
extern bool is_printablestring(chunk_t str);
extern realtime_t asn1totime(const chunk_t *utctime, asn1_t type);
extern void asn1_init(asn1_ctx_t *ctx, chunk_t blob,
		      u_int level0, bool implicit, u_int cond);
extern bool extract_object(const asn1Object_t *const objects,
			   u_int *objectID, chunk_t *object, u_int *level,
			   asn1_ctx_t *ctx);
extern bool is_asn1(chunk_t blob);