/* SPDX-License-Identifier: GPL-2.0-only */ /* * Copyright 2023 Red Hat */ #ifndef UDS_HASH_UTILS_H #define UDS_HASH_UTILS_H #include "numeric.h" #include "geometry.h" #include "indexer.h" /* Utilities for extracting portions of a request name for various uses. */ /* How various portions of a record name are apportioned. */ enum { VOLUME_INDEX_BYTES_OFFSET = 0, VOLUME_INDEX_BYTES_COUNT = 8, CHAPTER_INDEX_BYTES_OFFSET = 8, CHAPTER_INDEX_BYTES_COUNT = 6, SAMPLE_BYTES_OFFSET = 14, SAMPLE_BYTES_COUNT = 2, }; static inline u64 uds_extract_chapter_index_bytes(const struct uds_record_name *name) { const u8 *chapter_bits = &name->name[CHAPTER_INDEX_BYTES_OFFSET]; u64 bytes = (u64) get_unaligned_be16(chapter_bits) << 32; bytes |= get_unaligned_be32(chapter_bits + 2); return bytes; } static inline u64 uds_extract_volume_index_bytes(const struct uds_record_name *name) { return get_unaligned_be64(&name->name[VOLUME_INDEX_BYTES_OFFSET]); } static inline u32 uds_extract_sampling_bytes(const struct uds_record_name *name) { return get_unaligned_be16(&name->name[SAMPLE_BYTES_OFFSET]); } /* Compute the chapter delta list for a given name. */ static inline u32 uds_hash_to_chapter_delta_list(const struct uds_record_name *name, const struct index_geometry *geometry) { return ((uds_extract_chapter_index_bytes(name) >> geometry->chapter_address_bits) & ((1 << geometry->chapter_delta_list_bits) - 1)); } /* Compute the chapter delta address for a given name. */ static inline u32 uds_hash_to_chapter_delta_address(const struct uds_record_name *name, const struct index_geometry *geometry) { return uds_extract_chapter_index_bytes(name) & ((1 << geometry->chapter_address_bits) - 1); } static inline unsigned int uds_name_to_hash_slot(const struct uds_record_name *name, unsigned int slot_count) { return (unsigned int) (uds_extract_chapter_index_bytes(name) % slot_count); } #endif /* UDS_HASH_UTILS_H */