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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111/* SPDX-License-Identifier: GPL-2.0-only */#ifndef _LINUX_CRC32_H#define _LINUX_CRC32_H
#include <linux/types.h>#include <linux/bitrev.h>
/** * crc32_le() - Compute least-significant-bit-first IEEE CRC-32 * @crc: Initial CRC value. ~0 (recommended) or 0 for a new CRC computation, or * the previous CRC value if computing incrementally. * @p: Pointer to the data buffer * @len: Length of data in bytes * * This implements the CRC variant that is often known as the IEEE CRC-32, or * simply CRC-32, and is widely used in Ethernet and other applications: * * - Polynomial: x^32 + x^26 + x^23 + x^22 + x^16 + x^12 + x^11 + x^10 + x^8 + * x^7 + x^5 + x^4 + x^2 + x^1 + x^0 * - Bit order: Least-significant-bit-first * - Polynomial in integer form: 0xedb88320 * * This does *not* invert the CRC at the beginning or end. The caller is * expected to do that if it needs to. Inverting at both ends is recommended. * * For new applications, prefer to use CRC-32C instead. See crc32c(). * * Context: Any context * Return: The new CRC value */u32 crc32_le(u32 crc, const void *p, size_t len);
/* This is just an alias for crc32_le(). */static inline u32 crc32(u32 crc, const void *p, size_t len){ return crc32_le(crc, p, len);}
/** * crc32_be() - Compute most-significant-bit-first IEEE CRC-32 * @crc: Initial CRC value. ~0 (recommended) or 0 for a new CRC computation, or * the previous CRC value if computing incrementally. * @p: Pointer to the data buffer * @len: Length of data in bytes * * crc32_be() is the same as crc32_le() except that crc32_be() computes the * *most-significant-bit-first* variant of the CRC. I.e., within each byte, the * most significant bit is processed first (treated as highest order polynomial * coefficient). The same bit order is also used for the CRC value itself: * * - Polynomial: x^32 + x^26 + x^23 + x^22 + x^16 + x^12 + x^11 + x^10 + x^8 + * x^7 + x^5 + x^4 + x^2 + x^1 + x^0 * - Bit order: Most-significant-bit-first * - Polynomial in integer form: 0x04c11db7 * * Context: Any context * Return: The new CRC value */u32 crc32_be(u32 crc, const void *p, size_t len);
/** * crc32c() - Compute CRC-32C * @crc: Initial CRC value. ~0 (recommended) or 0 for a new CRC computation, or * the previous CRC value if computing incrementally. * @p: Pointer to the data buffer * @len: Length of data in bytes * * This implements CRC-32C, i.e. the Castagnoli CRC. This is the recommended * CRC variant to use in new applications that want a 32-bit CRC. * * - Polynomial: x^32 + x^28 + x^27 + x^26 + x^25 + x^23 + x^22 + x^20 + x^19 + * x^18 + x^14 + x^13 + x^11 + x^10 + x^9 + x^8 + x^6 + x^0 * - Bit order: Least-significant-bit-first * - Polynomial in integer form: 0x82f63b78 * * This does *not* invert the CRC at the beginning or end. The caller is * expected to do that if it needs to. Inverting at both ends is recommended. * * Context: Any context * Return: The new CRC value */u32 crc32c(u32 crc, const void *p, size_t len);
/* * crc32_optimizations() returns flags that indicate which CRC32 library * functions are using architecture-specific optimizations. Unlike * IS_ENABLED(CONFIG_CRC32_ARCH) it takes into account the different CRC32 * variants and also whether any needed CPU features are available at runtime. */#define CRC32_LE_OPTIMIZATION BIT(0) /* crc32_le() is optimized */#define CRC32_BE_OPTIMIZATION BIT(1) /* crc32_be() is optimized */#define CRC32C_OPTIMIZATION BIT(2) /* crc32c() is optimized */#if IS_ENABLED(CONFIG_CRC32_ARCH)u32 crc32_optimizations(void);#elsestatic inline u32 crc32_optimizations(void) { return 0; }#endif
/* * Helpers for hash table generation of ethernet nics: * * Ethernet sends the least significant bit of a byte first, thus crc32_le * is used. The output of crc32_le is bit reversed [most significant bit * is in bit nr 0], thus it must be reversed before use. Except for * nics that bit swap the result internally... */#define ether_crc(length, data) bitrev32(crc32_le(~0, data, length))#define ether_crc_le(length, data) crc32_le(~0, data, length)
#endif /* _LINUX_CRC32_H */