sha256.h

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#ifndef _IPXE_SHA256_H
#define _IPXE_SHA256_H

/** @file
 *
 * SHA-256 algorithm
 *
 */

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );

#include <stdint.h>
#include <ipxe/crypto.h>

/** SHA-256 number of rounds */
#define SHA256_ROUNDS 64

/** An SHA-256 digest */
struct sha256_digest {
        /** Hash output */
        uint32_t h[8];
};

/** An SHA-256 data block */
union sha256_block {
        /** Raw bytes */
        uint8_t byte[64];
        /** Raw dwords */
        uint32_t dword[16];
        /** Final block structure */
        struct {
                /** Padding */
                uint8_t pad[56];
                /** Length in bits */
                uint64_t len;
        } final;
};

/** SHA-256 digest and data block
 *
 * The order of fields within this structure is designed to minimise
 * code size.
 */
struct sha256_digest_data {
        /** Digest of data already processed */
        struct sha256_digest digest;
        /** Accumulated data */
        union sha256_block data;
} __attribute__ (( packed ));

/** SHA-256 digest and data block */
union sha256_digest_data_dwords {
        /** Digest and data block */
        struct sha256_digest_data dd;
        /** Raw dwords */
        uint32_t dword[ sizeof ( struct sha256_digest_data ) /
                        sizeof ( uint32_t ) ];
};

/** An SHA-256 context */
struct sha256_context {
        /** Amount of accumulated data */
        size_t len;
        /** Digest size */
        size_t digestsize;
        /** Digest and accumulated data */
        union sha256_digest_data_dwords ddd;
} __attribute__ (( packed ));

/** SHA-256 context size */
#define SHA256_CTX_SIZE sizeof ( struct sha256_context )

/** SHA-256 block size */
#define SHA256_BLOCK_SIZE sizeof ( union sha256_block )

/** SHA-256 digest size */
#define SHA256_DIGEST_SIZE sizeof ( struct sha256_digest )

/** SHA-224 digest size */
#define SHA224_DIGEST_SIZE ( SHA256_DIGEST_SIZE * 224 / 256 )

extern void sha256_family_init ( struct sha256_context *context,
                                 const struct sha256_digest *init,
                                 size_t digestsize );
extern void sha256_update ( void *ctx, const void *data, size_t len );
extern void sha256_final ( void *ctx, void *out );

extern struct digest_algorithm sha256_algorithm;
extern struct digest_algorithm sha224_algorithm;

#endif /* _IPXE_SHA256_H */