369991d997
Replace the BSD license header with the SPDX tag for files with only an Intel copyright on them. Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
110 lines
3.7 KiB
C
110 lines
3.7 KiB
C
/* SPDX-License-Identifier: BSD-3-Clause
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* Copyright(c) 2010-2017 Intel Corporation
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*/
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#ifndef __INCLUDE_RTE_TABLE_HASH_H__
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#define __INCLUDE_RTE_TABLE_HASH_H__
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#ifdef __cplusplus
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extern "C" {
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#endif
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/**
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* @file
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* RTE Table Hash
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*
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* These tables use the exact match criterion to uniquely associate data to
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* lookup keys.
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*
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* Hash table types:
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* 1. Entry add strategy on bucket full:
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* a. Least Recently Used (LRU): One of the existing keys in the bucket is
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* deleted and the new key is added in its place. The number of keys in
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* each bucket never grows bigger than 4. The logic to pick the key to
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* be dropped from the bucket is LRU. The hash table lookup operation
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* maintains the order in which the keys in the same bucket are hit, so
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* every time a key is hit, it becomes the new Most Recently Used (MRU)
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* key, i.e. the most unlikely candidate for drop. When a key is added
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* to the bucket, it also becomes the new MRU key. When a key needs to
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* be picked and dropped, the most likely candidate for drop, i.e. the
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* current LRU key, is always picked. The LRU logic requires maintaining
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* specific data structures per each bucket. Use-cases: flow cache, etc.
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* b. Extendible bucket (ext): The bucket is extended with space for 4 more
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* keys. This is done by allocating additional memory at table init time,
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* which is used to create a pool of free keys (the size of this pool is
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* configurable and always a multiple of 4). On key add operation, the
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* allocation of a group of 4 keys only happens successfully within the
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* limit of free keys, otherwise the key add operation fails. On key
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* delete operation, a group of 4 keys is freed back to the pool of free
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* keys when the key to be deleted is the only key that was used within
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* its group of 4 keys at that time. On key lookup operation, if the
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* current bucket is in extended state and a match is not found in the
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* first group of 4 keys, the search continues beyond the first group of
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* 4 keys, potentially until all keys in this bucket are examined. The
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* extendible bucket logic requires maintaining specific data structures
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* per table and per each bucket. Use-cases: flow table, etc.
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* 2. Key size:
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* a. Configurable key size
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* b. Single key size (8-byte, 16-byte or 32-byte key size)
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*
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***/
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#include <stdint.h>
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#include "rte_table.h"
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/** Hash function */
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typedef uint64_t (*rte_table_hash_op_hash)(
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void *key,
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void *key_mask,
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uint32_t key_size,
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uint64_t seed);
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/** Hash table parameters */
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struct rte_table_hash_params {
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/** Name */
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const char *name;
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/** Key size (number of bytes) */
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uint32_t key_size;
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/** Byte offset within packet meta-data where the key is located */
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uint32_t key_offset;
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/** Key mask */
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uint8_t *key_mask;
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/** Number of keys */
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uint32_t n_keys;
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/** Number of buckets */
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uint32_t n_buckets;
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/** Hash function */
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rte_table_hash_op_hash f_hash;
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/** Seed value for the hash function */
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uint64_t seed;
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};
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/** Extendible bucket hash table operations */
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extern struct rte_table_ops rte_table_hash_ext_ops;
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extern struct rte_table_ops rte_table_hash_key8_ext_ops;
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extern struct rte_table_ops rte_table_hash_key16_ext_ops;
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extern struct rte_table_ops rte_table_hash_key32_ext_ops;
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/** LRU hash table operations */
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extern struct rte_table_ops rte_table_hash_lru_ops;
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extern struct rte_table_ops rte_table_hash_key8_lru_ops;
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extern struct rte_table_ops rte_table_hash_key16_lru_ops;
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extern struct rte_table_ops rte_table_hash_key32_lru_ops;
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/** Cuckoo hash table operations */
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extern struct rte_table_ops rte_table_hash_cuckoo_ops;
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#ifdef __cplusplus
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}
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#endif
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#endif
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