rte_fbk_hash.c

/* SPDX-License-Identifier: BSD-3-Clause
 * Copyright(c) 2010-2014 Intel Corporation
 */

#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <sys/queue.h>

#include <rte_cpuflags.h>
#include <rte_eal_memconfig.h>
#include <rte_malloc.h>
#include <rte_common.h>
#include <rte_errno.h>
#include <rte_string_fns.h>
#include <rte_log.h>
#include <rte_tailq.h>

#include "rte_fbk_hash.h"

RTE_LOG_REGISTER_SUFFIX(fbk_hash_logtype, fbk, INFO);
#define RTE_LOGTYPE_HASH fbk_hash_logtype
#define HASH_LOG(level, ...) \
	RTE_LOG_LINE(level, HASH, "" __VA_ARGS__)

TAILQ_HEAD(rte_fbk_hash_list, rte_tailq_entry);

static struct rte_tailq_elem rte_fbk_hash_tailq = {
	.name = "RTE_FBK_HASH",
};
EAL_REGISTER_TAILQ(rte_fbk_hash_tailq)

/**
 * Performs a lookup for an existing hash table, and returns a pointer to
 * the table if found.
 *
 * @param name
 *   Name of the hash table to find
 *
 * @return
 *   pointer to hash table structure or NULL on error.
 */
struct rte_fbk_hash_table *
rte_fbk_hash_find_existing(const char *name)
{
	struct rte_fbk_hash_table *h = NULL;
	struct rte_tailq_entry *te;
	struct rte_fbk_hash_list *fbk_hash_list;

	fbk_hash_list = RTE_TAILQ_CAST(rte_fbk_hash_tailq.head,
				       rte_fbk_hash_list);

	rte_mcfg_tailq_read_lock();
	TAILQ_FOREACH(te, fbk_hash_list, next) {
		h = (struct rte_fbk_hash_table *) te->data;
		if (strncmp(name, h->name, RTE_FBK_HASH_NAMESIZE) == 0)
			break;
	}
	rte_mcfg_tailq_read_unlock();
	if (te == NULL) {
		rte_errno = ENOENT;
		return NULL;
	}
	return h;
}

/**
 * Create a new hash table for use with four byte keys.
 *
 * @param params
 *   Parameters used in creation of hash table.
 *
 * @return
 *   Pointer to hash table structure that is used in future hash table
 *   operations, or NULL on error.
 */
struct rte_fbk_hash_table *
rte_fbk_hash_create(const struct rte_fbk_hash_params *params)
{
	struct rte_fbk_hash_table *ht = NULL;
	struct rte_tailq_entry *te;
	char hash_name[RTE_FBK_HASH_NAMESIZE];
	const uint32_t mem_size =
			sizeof(*ht) + (sizeof(ht->t[0]) * params->entries);
	uint32_t i;
	struct rte_fbk_hash_list *fbk_hash_list;
	rte_fbk_hash_fn default_hash_func = (rte_fbk_hash_fn)rte_jhash_1word;

	fbk_hash_list = RTE_TAILQ_CAST(rte_fbk_hash_tailq.head,
				       rte_fbk_hash_list);

	/* Error checking of parameters. */
	if ((!rte_is_power_of_2(params->entries)) ||
			(!rte_is_power_of_2(params->entries_per_bucket)) ||
			(params->entries == 0) ||
			(params->entries_per_bucket == 0) ||
			(params->entries_per_bucket > params->entries) ||
			(params->entries > RTE_FBK_HASH_ENTRIES_MAX) ||
			(params->entries_per_bucket > RTE_FBK_HASH_ENTRIES_PER_BUCKET_MAX)){
		rte_errno = EINVAL;
		return NULL;
	}

	snprintf(hash_name, sizeof(hash_name), "FBK_%s", params->name);

	rte_mcfg_tailq_write_lock();

	/* guarantee there's no existing */
	TAILQ_FOREACH(te, fbk_hash_list, next) {
		ht = (struct rte_fbk_hash_table *) te->data;
		if (strncmp(params->name, ht->name, RTE_FBK_HASH_NAMESIZE) == 0)
			break;
	}
	ht = NULL;
	if (te != NULL) {
		rte_errno = EEXIST;
		goto exit;
	}

	te = rte_zmalloc("FBK_HASH_TAILQ_ENTRY", sizeof(*te), 0);
	if (te == NULL) {
		HASH_LOG(ERR, "Failed to allocate tailq entry");
		goto exit;
	}

	/* Allocate memory for table. */
	ht = rte_zmalloc_socket(hash_name, mem_size,
			0, params->socket_id);
	if (ht == NULL) {
		HASH_LOG(ERR, "Failed to allocate fbk hash table");
		rte_free(te);
		goto exit;
	}

	/* Default hash function */
#if defined(RTE_ARCH_X86)
	default_hash_func = (rte_fbk_hash_fn)rte_hash_crc_4byte;
#elif defined(RTE_ARCH_ARM64)
	if (rte_cpu_get_flag_enabled(RTE_CPUFLAG_CRC32))
		default_hash_func = (rte_fbk_hash_fn)rte_hash_crc_4byte;
#endif

	/* Set up hash table context. */
	strlcpy(ht->name, params->name, sizeof(ht->name));
	ht->entries = params->entries;
	ht->entries_per_bucket = params->entries_per_bucket;
	ht->used_entries = 0;
	ht->bucket_mask = (params->entries / params->entries_per_bucket) - 1;
	for (ht->bucket_shift = 0, i = 1;
	    (params->entries_per_bucket & i) == 0;
	    ht->bucket_shift++, i <<= 1)
		; /* empty loop body */

	if (params->hash_func != NULL) {
		ht->hash_func = params->hash_func;
		ht->init_val = params->init_val;
	}
	else {
		ht->hash_func = default_hash_func;
		ht->init_val = RTE_FBK_HASH_INIT_VAL_DEFAULT;
	}

	te->data = (void *) ht;

	TAILQ_INSERT_TAIL(fbk_hash_list, te, next);

exit:
	rte_mcfg_tailq_write_unlock();

	return ht;
}

/**
 * Free all memory used by a hash table.
 *
 * @param ht
 *   Hash table to deallocate.
 */
void
rte_fbk_hash_free(struct rte_fbk_hash_table *ht)
{
	struct rte_tailq_entry *te;
	struct rte_fbk_hash_list *fbk_hash_list;

	if (ht == NULL)
		return;

	fbk_hash_list = RTE_TAILQ_CAST(rte_fbk_hash_tailq.head,
				       rte_fbk_hash_list);

	rte_mcfg_tailq_write_lock();

	/* find out tailq entry */
	TAILQ_FOREACH(te, fbk_hash_list, next) {
		if (te->data == (void *) ht)
			break;
	}

	if (te == NULL) {
		rte_mcfg_tailq_write_unlock();
		return;
	}

	TAILQ_REMOVE(fbk_hash_list, te, next);

	rte_mcfg_tailq_write_unlock();

	rte_free(ht);
	rte_free(te);
}