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/*
* BIRD Library -- Message Authentication Codes
*
* (c) 2016 Ondrej Zajicek <santiago@crfreenet.org>
* (c) 2016 CZ.NIC z.s.p.o.
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
#ifndef _BIRD_MAC_H_
#define _BIRD_MAC_H_
#include "nest/bird.h"
#include "lib/sha512.h"
#define ALG_UNDEFINED 0
#define ALG_MD5 0x01
#define ALG_SHA1 0x02
#define ALG_SHA224 0x03
#define ALG_SHA256 0x04
#define ALG_SHA384 0x05
#define ALG_SHA512 0x06
#define ALG_HMAC 0x10
#define ALG_HMAC_MD5 0x11
#define ALG_HMAC_SHA1 0x12
#define ALG_HMAC_SHA224 0x13
#define ALG_HMAC_SHA256 0x14
#define ALG_HMAC_SHA384 0x15
#define ALG_HMAC_SHA512 0x16
#define ALG_MAX 0x17
/* These are maximums for HASH/MAC lengths and required context space */
#define MAX_HASH_SIZE SHA512_SIZE
#define HASH_STORAGE sizeof(struct sha512_context)
#define MAC_STORAGE sizeof(struct hmac_context)
/* This value is used by several IETF protocols for padding */
#define HMAC_MAGIC htonl(0x878FE1F3)
/* Generic context used by hash functions */
struct hash_context
{
u8 data[HASH_STORAGE];
u64 align[0];
};
/* Context for embedded hash (not-really-MAC hash) */
struct nrmh_context {
const struct mac_desc *type;
struct hash_context ictx;
};
/* Context for hash based HMAC */
struct hmac_context {
const struct mac_desc *type;
struct hash_context ictx;
struct hash_context octx;
};
/* Generic context used by MAC functions */
struct mac_context
{
const struct mac_desc *type;
u8 data[MAC_STORAGE - sizeof(void *)];
u64 align[0];
};
/* Union to satisfy C aliasing rules */
union mac_context_union {
struct mac_context mac;
struct nrmh_context nrmh;
struct hmac_context hmac;
};
struct mac_desc {
const char *name; /* Name of MAC algorithm */
uint mac_length; /* Length of authentication code */
uint ctx_length; /* Length of algorithm context */
void (*init)(struct mac_context *ctx, const byte *key, uint keylen);
void (*update)(struct mac_context *ctx, const byte *data, uint datalen);
byte *(*final)(struct mac_context *ctx);
uint hash_size; /* Hash length, for hash-based MACs */
uint block_size; /* Hash block size, for hash-based MACs */
void (*hash_init)(struct hash_context *ctx);
void (*hash_update)(struct hash_context *ctx, const byte *data, uint datalen);
byte *(*hash_final)(struct hash_context *ctx);
};
const struct mac_desc mac_table[ALG_MAX];
static inline const char *mac_type_name(uint id)
{ return mac_table[id].name; }
static inline uint mac_type_length(uint id)
{ return mac_table[id].mac_length; }
static inline const char *mac_get_name(struct mac_context *ctx)
{ return ctx->type->name; }
static inline uint mac_get_length(struct mac_context *ctx)
{ return ctx->type->mac_length; }
void mac_init(struct mac_context *ctx, uint id, const byte *key, uint keylen);
static inline void mac_update(struct mac_context *ctx, const byte *data, uint datalen)
{ ctx->type->update(ctx, data, datalen); }
static inline byte *mac_final(struct mac_context *ctx)
{ return ctx->type->final(ctx); }
static inline void mac_cleanup(struct mac_context *ctx)
{ memset(ctx, 0, ctx->type->ctx_length); }
void mac_fill(uint id, const byte *key, uint keylen, const byte *data, uint datalen, byte *mac);
int mac_verify(uint id, const byte *key, uint keylen, const byte *data, uint datalen, const byte *mac);
#endif /* _BIRD_MAC_H_ */
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