hmac.h

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#ifndef _IPXE_HMAC_H
#define _IPXE_HMAC_H

/** @file
 *
 * Keyed-Hashing for Message Authentication
 */

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
FILE_SECBOOT ( PERMITTED );

#include <ipxe/crypto.h>

/** HMAC context type */
#define hmac_context_t( digest ) struct {                               \
                /** Digest context */                                   \
                uint8_t ctx[ digest->ctxsize ];                         \
                /** HMAC input/output padding */                        \
                uint8_t pad[ digest->blocksize ];                       \
        } __attribute__ (( packed ))

/**
 * Calculate HMAC context size
 *
 * @v digest            Digest algorithm to use
 * @ret len             HMAC context size
 */
static inline __attribute__ (( always_inline )) size_t
hmac_ctxsize ( struct digest_algorithm *digest ) {
        hmac_context_t ( digest ) *hctx;

        return sizeof ( *hctx );
}

/**
 * Update HMAC
 *
 * @v digest            Digest algorithm to use
 * @v ctx               HMAC context
 * @v data              Data
 * @v len               Length of data
 */
static inline void hmac_update ( struct digest_algorithm *digest, void *ctx,
                                 const void *data, size_t len ) {
        hmac_context_t ( digest ) *hctx = ctx;

        digest_update ( digest, hctx->ctx, data, len );
}

extern void hmac_init ( struct digest_algorithm *digest, void *ctx,
                        const void *key, size_t key_len );
extern void hmac_final ( struct digest_algorithm *digest, void *ctx,
                         void *hmac );

#endif /* _IPXE_HMAC_H */