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/**************************************************//**
@file include/log0crypt.h
Innodb log encrypt/decrypt

Created 11/25/2013 Minli Zhu
Modified           Jan Lindström jan.lindstrom@mariadb.com
MDEV-11782: Rewritten for MariaDB 10.2 by Marko Mäkelä, MariaDB Corporation.
*******************************************************/
#ifndef log0crypt_h
#define log0crypt_h

#include "log0log.h"

/** innodb_encrypt_log: whether to encrypt the redo log */
extern my_bool srv_encrypt_log;

/** Initialize the redo log encryption key and random parameters
when creating a new redo log.
The random parameters will be persisted in the log checkpoint pages.
@see log_crypt_write_checkpoint_buf()
@see log_crypt_read_checkpoint_buf()
@return whether the operation succeeded */
bool log_crypt_init();

/*********************************************************************//**
Writes the crypto (version, msg and iv) info, which has been used for
log blocks with lsn <= this checkpoint's lsn, to a log header's
checkpoint buf. */
void log_crypt_write_checkpoint_buf(byte *buf);

/** Read the MariaDB 10.1 checkpoint crypto (version, msg and iv) info.
@param[in]	buf	checkpoint buffer
@return	whether the operation was successful */
ATTRIBUTE_COLD bool log_crypt_101_read_checkpoint(const byte* buf);

/** Decrypt a MariaDB 10.1 redo log block.
@param[in,out]	buf		log block
@param[in]	start_lsn	server start LSN
@return	whether the decryption was successful */
ATTRIBUTE_COLD bool log_crypt_101_read_block(byte* buf, lsn_t start_lsn);

/** Read the checkpoint crypto (version, msg and iv) info.
@param[in]	buf	checkpoint buffer
@return	whether the operation was successful */
bool log_crypt_read_checkpoint_buf(const byte* buf);

/** log_crypt() operation code */
enum log_crypt_t {
	/** encrypt a log block without rotating key */
	LOG_ENCRYPT,
	/** decrypt a log block */
	LOG_DECRYPT,
	/** attempt to rotate the key, and encrypt a log block */
	LOG_ENCRYPT_ROTATE_KEY
};

/** Encrypt or decrypt log blocks.
@param[in,out]	buf	log blocks to encrypt or decrypt
@param[in]	lsn	log sequence number of the start of the buffer
@param[in]	size	size of the buffer, in bytes
@param[in]	op	whether to decrypt, encrypt, or rotate key and encrypt
@return	whether the operation succeeded (encrypt always does) */
bool log_crypt(byte* buf, lsn_t lsn, ulint size, log_crypt_t op = LOG_ENCRYPT);

/** Encrypt or decrypt a temporary file block.
@param[in]	src		block to encrypt or decrypt
@param[in]	size		size of the block
@param[out]	dst		destination block
@param[in]	offs		offset to block
@param[in]	encrypt		true=encrypt; false=decrypt
@return whether the operation succeeded */
bool log_tmp_block_encrypt(
	const byte*	src,
	ulint		size,
	byte*		dst,
	uint64_t	offs,
	bool		encrypt = true)
	MY_ATTRIBUTE((warn_unused_result, nonnull));

/** Decrypt a temporary file block.
@param[in]	src		block to decrypt
@param[in]	size		size of the block
@param[out]	dst		destination block
@param[in]	offs		offset to block
@return whether the operation succeeded */
inline
bool
log_tmp_block_decrypt(
	const byte*	src,
	ulint		size,
	byte*		dst,
	uint64_t	offs)
{
	return(log_tmp_block_encrypt(src, size, dst, offs, false));
}

/** @return whether temporary files are encrypted */
inline bool log_tmp_is_encrypted() { return srv_encrypt_log; }
#endif  // log0crypt.h