src/include/ipxe/sha256.h

#ifndef _IPXE_SHA256_H
#define _IPXE_SHA256_H

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

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
FILE_SECBOOT ( PERMITTED );

#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 and accumulated data */
	union sha256_digest_data_dwords ddd;
} __attribute__ (( packed ));

/** A SHA-256 family algorithm */
struct sha256_algorithm {
	/** Initial digest values */
	const struct sha256_digest *init;
};

/** 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_init ( struct digest_algorithm *digest, void *ctx );
extern void sha256_update ( struct digest_algorithm *digest, void *ctx,
			    const void *data, size_t len );
extern void sha256_final ( struct digest_algorithm *digest, void *ctx,
			   void *out );

/** Define a SHA-256 family digest algorithm */
#define SHA256_ALGORITHM( _name, _digest, _digestsize, _init )		\
	static struct sha256_algorithm _name ## _sha256 = {		\
		.init		= (_init),				\
	};								\
	struct digest_algorithm _digest = {				\
		.name		= #_name,				\
		.ctxsize	= sizeof ( struct sha256_context ),	\
		.blocksize	= sizeof ( union sha256_block ),	\
		.digestsize	= (_digestsize),			\
		.init		= sha256_init,				\
		.update		= sha256_update,			\
		.final		= sha256_final,				\
		.priv		= &_name ## _sha256,			\
	}

extern struct digest_algorithm sha256_algorithm;
extern struct digest_algorithm sha224_algorithm;

#endif /* _IPXE_SHA256_H */