/*
   * Copyright (c) 2012 The Chromium OS Authors.
   * SPDX-License-Identifier:	GPL-2.0+
   */
  
  #ifndef _HASH_H
  #define _HASH_H
  
  /*
   * Maximum digest size for all algorithms we support. Having this value
   * avoids a malloc() or C99 local declaration in common/cmd_hash.c.
   */
  #define HASH_MAX_DIGEST_SIZE	32
  
  enum {
  	HASH_FLAG_VERIFY	= 1 << 0,	/* Enable verify mode */
  	HASH_FLAG_ENV		= 1 << 1,	/* Allow env vars */
  };
  
  #if defined(CONFIG_SHA1SUM_VERIFY) || defined(CONFIG_CRC32_VERIFY)
  #define CONFIG_HASH_VERIFY
  #endif
  
  struct hash_algo {
  	const char *name;			/* Name of algorithm */
  	int digest_size;			/* Length of digest */
  	/**
  	 * hash_func_ws: Generic hashing function
  	 *
  	 * This is the generic prototype for a hashing function. We only
  	 * have the watchdog version at present.
  	 *
  	 * @input:	Input buffer
  	 * @ilen:	Input buffer length
  	 * @output:	Checksum result (length depends on algorithm)
  	 * @chunk_sz:	Trigger watchdog after processing this many bytes
  	 */
  	void (*hash_func_ws)(const unsigned char *input, unsigned int ilen,
  		unsigned char *output, unsigned int chunk_sz);
  	int chunk_size;				/* Watchdog chunk size */
  	/*
  	 * hash_init: Create the context for progressive hashing
  	 *
  	 * @algo: Pointer to the hash_algo struct
  	 * @ctxp: Pointer to the pointer of the context for hashing
  	 * @return 0 if ok, -1 on error
  	 */
  	int (*hash_init)(struct hash_algo *algo, void **ctxp);
  	/*
  	 * hash_update: Perform hashing on the given buffer
  	 *
  	 * The context is freed by this function if an error occurs.
  	 *
  	 * @algo: Pointer to the hash_algo struct
  	 * @ctx: Pointer to the context for hashing
  	 * @buf: Pointer to the buffer being hashed
  	 * @size: Size of the buffer being hashed
  	 * @is_last: 1 if this is the last update; 0 otherwise
  	 * @return 0 if ok, -1 on error
  	 */
  	int (*hash_update)(struct hash_algo *algo, void *ctx, const void *buf,
  			   unsigned int size, int is_last);
  	/*
  	 * hash_finish: Write the hash result to the given buffer
  	 *
  	 * The context is freed by this function.
  	 *
  	 * @algo: Pointer to the hash_algo struct
  	 * @ctx: Pointer to the context for hashing
  	 * @dest_buf: Pointer to the buffer for the result
  	 * @size: Size of the buffer for the result
  	 * @return 0 if ok, -ENOSPC if size of the result buffer is too small
  	 *   or -1 on other errors
  	 */
  	int (*hash_finish)(struct hash_algo *algo, void *ctx, void *dest_buf,
  			   int size);
  };
  
  #ifndef USE_HOSTCC
  /**
   * hash_command: Process a hash command for a particular algorithm
   *
   * This common function is used to implement specific hash commands.
   *
   * @algo_name:		Hash algorithm being used (lower case!)
   * @flags:		Flags value (HASH_FLAG_...)
   * @cmdtp:		Pointer to command table entry
   * @flag:		Some flags normally 0 (see CMD_FLAG_.. above)
   * @argc:		Number of arguments (arg 0 must be the command text)
   * @argv:		Arguments
   */
  int hash_command(const char *algo_name, int flags, cmd_tbl_t *cmdtp, int flag,
  		 int argc, char * const argv[]);
  
  /**
   * hash_block() - Hash a block according to the requested algorithm
   *
   * The caller probably knows the hash length for the chosen algorithm, but
   * in order to provide a general interface, and output_size parameter is
   * provided.
   *
   * @algo_name:		Hash algorithm to use
   * @data:		Data to hash
   * @len:		Lengh of data to hash in bytes
   * @output:		Place to put hash value
   * @output_size:	On entry, pointer to the number of bytes available in
   *			output. On exit, pointer to the number of bytes used.
   *			If NULL, then it is assumed that the caller has
   *			allocated enough space for the hash. This is possible
   *			since the caller is selecting the algorithm.
   * @return 0 if ok, -ve on error: -EPROTONOSUPPORT for an unknown algorithm,
   * -ENOSPC if the output buffer is not large enough.
   */
  int hash_block(const char *algo_name, const void *data, unsigned int len,
  	       uint8_t *output, int *output_size);
  
  /**
   * hash_show() - Print out a hash algorithm and value
   *
   * You will get a message like this (without a newline at the end):
   *
   * "sha1 for 9eb3337c ... 9eb3338f ==> 7942ef1df479fd3130f716eb9613d107dab7e257"
   *
   * @algo:		Algorithm used for hash
   * @addr:		Address of data that was hashed
   * @len:		Length of data that was hashed
   * @output:		Hash value to display
   */
  void hash_show(struct hash_algo *algo, ulong addr, ulong len,
  	       uint8_t *output);
  
  #endif /* !USE_HOSTCC */
  
  /**
   * hash_lookup_algo() - Look up the hash_algo struct for an algorithm
   *
   * The function returns the pointer to the struct or -EPROTONOSUPPORT if the
   * algorithm is not available.
   *
   * @algo_name: Hash algorithm to look up
   * @algop: Pointer to the hash_algo struct if found
   *
   * @return 0 if ok, -EPROTONOSUPPORT for an unknown algorithm.
   */
  int hash_lookup_algo(const char *algo_name, struct hash_algo **algop);
  
  /**
   * hash_progressive_lookup_algo() - Look up hash_algo for prog. hash support
   *
   * The function returns the pointer to the struct or -EPROTONOSUPPORT if the
   * algorithm is not available with progressive hash support.
   *
   * @algo_name: Hash algorithm to look up
   * @algop: Pointer to the hash_algo struct if found
   *
   * @return 0 if ok, -EPROTONOSUPPORT for an unknown algorithm.
   */
  int hash_progressive_lookup_algo(const char *algo_name,
  				 struct hash_algo **algop);
  
  #endif