include/linux/blk-crypto.h

/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Copyright 2019 Google LLC
 */

#ifndef __LINUX_BLK_CRYPTO_H
#define __LINUX_BLK_CRYPTO_H

enum blk_crypto_mode_num {
	BLK_ENCRYPTION_MODE_INVALID,
	BLK_ENCRYPTION_MODE_AES_256_XTS,
	BLK_ENCRYPTION_MODE_AES_128_CBC_ESSIV,
	BLK_ENCRYPTION_MODE_ADIANTUM,
	BLK_ENCRYPTION_MODE_MAX,
};

#define BLK_CRYPTO_MAX_KEY_SIZE		64
/**
 * struct blk_crypto_config - an inline encryption key's crypto configuration
 * @crypto_mode: encryption algorithm this key is for
 * @data_unit_size: the data unit size for all encryption/decryptions with this
 *	key.  This is the size in bytes of each individual plaintext and
 *	ciphertext.  This is always a power of 2.  It might be e.g. the
 *	filesystem block size or the disk sector size.
 * @dun_bytes: the maximum number of bytes of DUN used when using this key
 */
struct blk_crypto_config {
	enum blk_crypto_mode_num crypto_mode;
	unsigned int data_unit_size;
	unsigned int dun_bytes;
};

/**
 * struct blk_crypto_key - an inline encryption key
 * @crypto_cfg: the crypto configuration (like crypto_mode, key size) for this
 *		key
 * @data_unit_size_bits: log2 of data_unit_size
 * @size: size of this key in bytes (determined by @crypto_cfg.crypto_mode)
 * @raw: the raw bytes of this key.  Only the first @size bytes are used.
 *
 * A blk_crypto_key is immutable once created, and many bios can reference it at
 * the same time.  It must not be freed until all bios using it have completed
 * and it has been evicted from all devices on which it may have been used.
 */
struct blk_crypto_key {
	struct blk_crypto_config crypto_cfg;
	unsigned int data_unit_size_bits;
	unsigned int size;
	u8 raw[BLK_CRYPTO_MAX_KEY_SIZE];
};

#endif /* __LINUX_BLK_CRYPTO_H */