lib: crc: Add OpenPGP CRC-24 (863f6aff) · Commits · Wenxi XU / zephyr

include/zephyr/sys/crc.h

+41 −2

Original line number	Diff line number	Diff line
		@@ -30,6 +30,14 @@ extern "C" {
		*/
		#define CRC8_CCITT_INITIAL_VALUE 0xFF

		/* Initial value expected to be used at the beginning of the OpenPGP CRC-24 computation. */
		#define CRC24_PGP_INITIAL_VALUE 0x00B704CEU
		/*
		* The CRC-24 value is stored on a 32-bit value, only the 3 least significant bytes
		* are meaningful. Use the following mask to only keep the CRC-24 value.
		*/
		#define CRC24_FINAL_VALUE_MASK 0x00FFFFFFU

		/**
		* @defgroup checksum Checksum
		* @ingroup os_services
		@@ -56,6 +64,7 @@ enum crc_type {
		CRC16_ANSI, /*< Use @ref crc16_ansi /
		CRC16_CCITT, /*< Use @ref crc16_ccitt /
		CRC16_ITU_T, /*< Use @ref crc16_itu_t /
		CRC24_PGP, /*< Use @ref crc24_pgp /
		CRC32_C, /*< Use @ref crc32_c /
		CRC32_IEEE, /*< Use @ref crc32_ieee /
		};
		@@ -315,16 +324,39 @@ uint8_t crc4_ti(uint8_t seed, const uint8_t *src, size_t len);
		uint8_t crc4(const uint8_t *src, size_t len, uint8_t polynomial, uint8_t initial_value,
		bool reversed);

		/**
		* @brief Generate an OpenPGP CRC-24 checksum as defined in RFC 4880 section 6.1.
		*
		* @param data A pointer to the data on which the CRC will be calculated.
		* @param len Data length in bytes.
		*
		* @return The CRC-24 value.
		*/
		uint32_t crc24_pgp(const uint8_t *data, size_t len);

		/**
		* @brief Update an OpenPGP CRC-24 checksum.
		*
		* @param crc The CRC-24 checksum that needs to be updated. The full 32-bit value of the CRC needs
		* to be used between calls, do not mask the value to keep only the last 24 bits.
		* @param data A pointer to the data on which the CRC will be calculated.
		* @param len Data length in bytes.
		*
		* @return The CRC-24 value. When the last buffer of data has been processed, mask the value
		* with CRC24_FINAL_VALUE_MASK to keep only the meaningful 24 bits of the CRC result.
		*/
		uint32_t crc24_pgp_update(uint32_t crc, const uint8_t *data, size_t len);

		/**
		* @brief Compute a CRC checksum, in a generic way.
		*
		* This is a dispatch function that calls the individual CRC routine
		* determined by @p type.
		*
		* For 7, 8, and 16-bit CRCs, the relevant @p seed and @p poly values should
		* For 7, 8, 16 and 24-bit CRCs, the relevant @p seed and @p poly values should
		* be passed in via the least-significant byte(s).
		*
		* Similarly, for 7, 8, and 16-bit CRCs, the relevant result is stored in the
		* Similarly, for 7, 8, 16 and 24-bit CRCs, the relevant result is stored in the
		* least-significant byte(s) of the returned value.
		*
		* @param type CRC algorithm to use.
		@@ -364,6 +396,13 @@ static inline uint32_t crc_by_type(enum crc_type type, const uint8_t *src, size_
		return crc16_ccitt(seed, src, len);
		case CRC16_ITU_T:
		return crc16_itu_t(seed, src, len);
		case CRC24_PGP: {
		uint32_t crc = crc24_pgp_update(seed, src, len);

		if (last)
		crc &= CRC24_FINAL_VALUE_MASK;
		return crc;
		}
		case CRC32_C:
		return crc32_c(seed, src, len, first, last);
		case CRC32_IEEE:

lib/crc/CMakeLists.txt

+1 −0

Original line number	Diff line number	Diff line
		@@ -3,6 +3,7 @@
		zephyr_sources_ifdef(CONFIG_CRC
		crc32c_sw.c
		crc32_sw.c
		crc24_sw.c
		crc16_sw.c
		crc8_sw.c
		crc7_sw.c

lib/crc/crc24_sw.c

0 → 100644

+31 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2024 BayLibre.
		*
		* SPDX-License-Identifier: Apache-2.0
		*/

		#include <zephyr/sys/crc.h>

		#define CRC24_PGP_POLY 0x01864cfbU

		uint32_t crc24_pgp(const uint8_t *data, size_t len)
		{
		return crc24_pgp_update(CRC24_PGP_INITIAL_VALUE, data, len) & CRC24_FINAL_VALUE_MASK;
		}

		/* CRC-24 implementation from the section 6.1 of the RFC 4880 */
		uint32_t crc24_pgp_update(uint32_t crc, const uint8_t *data, size_t len)
		{
		int i;

		while (len--) {
		crc ^= (*data++) << 16;
		for (i = 0; i < 8; i++) {
		crc <<= 1;
		if (crc & 0x01000000)
		crc ^= CRC24_PGP_POLY;
		}
		}

		return crc;
		}

lib/crc/crc_shell.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -28,6 +28,7 @@ static const char *const crc_types[] = {
		[CRC16_ANSI] = "16_ansi",
		[CRC16_CCITT] = "16_ccitt",
		[CRC16_ITU_T] = "16_itu_t",
		[CRC24_PGP] = "24_pgp",
		[CRC32_C] = "32_c",
		[CRC32_IEEE] = "32_ieee",
		};

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