Coldwave Documentation

Appearance

file ota/checksum.h ​

Types ​

Name
typedef uint8_t[(64)]ota_checksum_t
typedef char[(15)+1]ota_checksum_algorithm_t

Functions Overview ​

Name
int8_tota_checksum_algorithm_supported(ota_checksum_algorithm_t const algorithm)
uint8_tota_checksum_algorithm_digest_length(ota_checksum_algorithm_t const algorithm)
int8_tota_checksum_match(const unsigned char * data, size_t datalen, ota_checksum_algorithm_t const algorithm, const ota_checksum_t cs)
voidota_sha1(ota_checksum_t out, char * begin, size_t size)

Defines ​

Name
OTA_CHECKSUM_NO_MATCH
OTA_CHECKSUM_UNSUPPORTED_ALGO
OTA_CHECKSUM_ALGO_OK
OTA_CHECKSUM_MATCH
OTA_CHECKSUM_VALUE_SIZE_MAX
OTA_CHECKSUM_ALGORITHM_NAME_STRLEN_MAX
OTA_CHECKSUM_ALGORITHM_SHA1
OTA_SHA1_DIGEST_LENGTH

Types Documentation ​

typedef ota_checksum_t ​

cpp
typedef uint8_t ota_checksum_t[(64)];

A checksum value type, valid for any supported algorithm. Algorithms with shorter checksums will simply ignore a number of entries at the back of the array.

typedef ota_checksum_algorithm_t ​

cpp
typedef char ota_checksum_algorithm_t[(15)+1];

A fixed-size string type for checksum-algorithm names. It is safer to identify algorithms by name than with an enmeration so we have backwards compatibility between different versions of this library without worrying about preserving and documenting the value of each enum case.

Function Details ​

function ota_checksum_algorithm_supported ​

cpp
int8_t ota_checksum_algorithm_supported(
    ota_checksum_algorithm_t const algorithm
)

function ota_checksum_algorithm_digest_length ​

cpp
uint8_t ota_checksum_algorithm_digest_length(
    ota_checksum_algorithm_t const algorithm
)

function ota_checksum_match ​

cpp
int8_t ota_checksum_match(
    const unsigned char * data,
    size_t datalen,
    ota_checksum_algorithm_t const algorithm,
    const ota_checksum_t cs
)

function ota_sha1 ​

cpp
void ota_sha1(
    ota_checksum_t out,
    char * begin,
    size_t size
)

It is your responsibility to implement this function, which should compute the SHA-1 hash of the data written in flash memory from address begin to address begin + size (not included). The resulting hash should be written at the beginning of the out array.

The reason why no default implementation is given with this library is because SHA-1 can often be computed in-place with a very efficient hardware implementation, in which case ota_sha1 can be written as a simple wrapper for the corresponding interface.

Macros Documentation ​

define OTA_CHECKSUM_NO_MATCH ​

cpp
#define OTA_CHECKSUM_NO_MATCH (-3)

define OTA_CHECKSUM_UNSUPPORTED_ALGO ​

cpp
#define OTA_CHECKSUM_UNSUPPORTED_ALGO (-1)

define OTA_CHECKSUM_ALGO_OK ​

cpp
#define OTA_CHECKSUM_ALGO_OK ( 0)

define OTA_CHECKSUM_MATCH ​

cpp
#define OTA_CHECKSUM_MATCH ( 0)

define OTA_CHECKSUM_VALUE_SIZE_MAX ​

cpp
#define OTA_CHECKSUM_VALUE_SIZE_MAX (64)

The maximum size of a checksum, for any algorithm currently used or that might be used in the foreseeable future.

define OTA_CHECKSUM_ALGORITHM_NAME_STRLEN_MAX ​

cpp
#define OTA_CHECKSUM_ALGORITHM_NAME_STRLEN_MAX (15)

The maximum length of a string representing the name of a checksum-algorithm (as given by strlen, i.e. not counting the terminating '\0').

define OTA_CHECKSUM_ALGORITHM_SHA1 ​

cpp
#define OTA_CHECKSUM_ALGORITHM_SHA1 "SHA1"

BEGIN: SHA-1 support Identifier string for algorithm SHA-1.

define OTA_SHA1_DIGEST_LENGTH ​

cpp
#define OTA_SHA1_DIGEST_LENGTH (20)

Actual length of a checksum returned from the SHA-1 algorithm. These many bytes at the beginning of the ota_checksum_t array are used, while the remaining bytes are ignored.

Source code ​

cpp
/*******************************************************************************
 * @file       checksum.h
 * @brief
 * @copyright  Copyright (c) 2023. ImagineOn GmbH. www.imagineon.de
 *             All rights reserved.
 ******************************************************************************/


#ifndef OTA_CHECKSUM_H
#define OTA_CHECKSUM_H

#include <stdint.h>

#if defined (__cplusplus)
extern "C" {
#endif

#define OTA_CHECKSUM_NO_MATCH          (-3)
#define OTA_CHECKSUM_UNSUPPORTED_ALGO  (-1)
#define OTA_CHECKSUM_ALGO_OK           ( 0)
#define OTA_CHECKSUM_MATCH             ( 0)

#define OTA_CHECKSUM_VALUE_SIZE_MAX (64)

typedef uint8_t ota_checksum_t[OTA_CHECKSUM_VALUE_SIZE_MAX];

#define OTA_CHECKSUM_ALGORITHM_NAME_STRLEN_MAX (15)

typedef char ota_checksum_algorithm_t[OTA_CHECKSUM_ALGORITHM_NAME_STRLEN_MAX + 1];

int8_t
ota_checksum_algorithm_supported (ota_checksum_algorithm_t const algorithm);

uint8_t
ota_checksum_algorithm_digest_length (ota_checksum_algorithm_t const algorithm);

int8_t
ota_checksum_match (const unsigned char *data, size_t datalen,
                    ota_checksum_algorithm_t const algorithm, const ota_checksum_t cs);


#define OTA_CHECKSUM_ALGORITHM_SHA1  "SHA1"

#define  OTA_SHA1_DIGEST_LENGTH  (20)

void ota_sha1 (ota_checksum_t out, char *begin, size_t size);


#if defined (__cplusplus)
}
#endif

#endif /* OTA_CHECKSUM_H */