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+/*-
+ * BSD LICENSE
+ *
+ * Copyright(c) 2010-2012 Intel Corporation. All rights reserved.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ * * Neither the name of Intel Corporation nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * version: DPDK.L.1.2.3-3
+ */
+
+#ifndef _RTE_FBK_HASH_H_
+#define _RTE_FBK_HASH_H_
+
+/**
+ * @file
+ *
+ * This is a hash table implementation for four byte keys (fbk).
+ *
+ * Note that the return value of the add function should always be checked as,
+ * if a bucket is full, the key is not added even if there is space in other
+ * buckets. This keeps the lookup function very simple and therefore fast.
+ */
+
+#include <stdint.h>
+#include <errno.h>
+#include <sys/queue.h>
+#include <rte_hash_crc.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <string.h>
+
+#ifndef RTE_FBK_HASH_FUNC_DEFAULT
+/** Default four-byte key hash function if none is specified. */
+#define RTE_FBK_HASH_FUNC_DEFAULT rte_hash_crc_4byte
+#endif
+
+#ifndef RTE_FBK_HASH_INIT_VAL_DEFAULT
+/** Initialising value used when calculating hash. */
+#define RTE_FBK_HASH_INIT_VAL_DEFAULT 0xFFFFFFFF
+#endif
+
+/** The maximum number of entries in the hash table that is supported. */
+#define RTE_FBK_HASH_ENTRIES_MAX (1 << 20)
+
+/** The maximum number of entries in each bucket that is supported. */
+#define RTE_FBK_HASH_ENTRIES_PER_BUCKET_MAX 256
+
+/** Maximum size of string for naming the hash. */
+#define RTE_FBK_HASH_NAMESIZE 32
+
+/** Type of function that can be used for calculating the hash value. */
+typedef uint32_t (*rte_fbk_hash_fn)(uint32_t key, uint32_t init_val);
+
+/** Parameters used when creating four-byte key hash table. */
+struct rte_fbk_hash_params {
+ const char *name; /**< Name of the hash table. */
+ uint32_t entries; /**< Total number of entries. */
+ uint32_t entries_per_bucket; /**< Number of entries in a bucket. */
+ int socket_id; /**< Socket to allocate memory on. */
+ rte_fbk_hash_fn hash_func; /**< The hash function. */
+ uint32_t init_val; /**< For initialising hash function. */
+};
+
+/** Individual entry in the four-byte key hash table. */
+union rte_fbk_hash_entry {
+ uint64_t whole_entry; /**< For accessing entire entry. */
+ struct {
+ uint16_t is_entry; /**< Non-zero if entry is active. */
+ uint16_t value; /**< Value returned by lookup. */
+ uint32_t key; /**< Key used to find value. */
+ } entry; /**< For accessing each entry part. */
+} ;
+
+
+
+/** The four-byte key hash table structure. */
+struct rte_fbk_hash_table {
+ TAILQ_ENTRY(rte_fbk_hash_table) next; /**< Linked list. */
+
+ char name[RTE_FBK_HASH_NAMESIZE]; /**< Name of the hash. */
+ uint32_t entries; /**< Total number of entries. */
+ uint32_t entries_per_bucket; /**< Number of entries in a bucket. */
+ uint32_t used_entries; /**< How many entries are used. */
+ uint32_t bucket_mask; /**< To find which bucket the key is in. */
+ uint32_t bucket_shift; /**< Convert bucket to table offset. */
+ rte_fbk_hash_fn hash_func; /**< The hash function. */
+ uint32_t init_val; /**< For initialising hash function. */
+
+ /** A flat table of all buckets. */
+ union rte_fbk_hash_entry t[0];
+};
+
+/**
+ * Find the offset into hash table of the bucket containing a particular key.
+ *
+ * @param ht
+ * Pointer to hash table.
+ * @param key
+ * Key to calculate bucket for.
+ * @return
+ * Offset into hash table.
+ */
+static inline uint32_t
+rte_fbk_hash_get_bucket(const struct rte_fbk_hash_table *ht, uint32_t key)
+{
+ return (ht->hash_func(key, ht->init_val) & ht->bucket_mask) <<
+ ht->bucket_shift;
+}
+
+
+/**
+ * Add a key to an existing hash table. This operation is not multi-thread safe
+ * and should only be called from one thread.
+ *
+ * @param ht
+ * Hash table to add the key to.
+ * @param key
+ * Key to add to the hash table.
+ * @param value
+ * Value to associate with key.
+ * @return
+ * 0 if ok, or negative value on error.
+ */
+static inline int
+rte_fbk_hash_add_key(struct rte_fbk_hash_table *ht,
+ uint32_t key, uint16_t value)
+{
+ /*
+ * The writing of a new value to the hash table is done as a single
+ * 64bit operation. This should help prevent individual entries being
+ * corrupted due to race conditions, but it's still possible to
+ * overwrite entries that have just been made valid.
+ */
+ const uint64_t new_entry = ((uint64_t)(key) << 32) |
+ ((uint64_t)(value) << 16) |
+ 1; /* 1 = is_entry bit. */
+ const uint32_t bucket = rte_fbk_hash_get_bucket(ht, key);
+ uint32_t i;
+
+ for (i = 0; i < ht->entries_per_bucket; i++) {
+ /* Set entry if unused. */
+ if (! ht->t[bucket + i].entry.is_entry) {
+ ht->t[bucket + i].whole_entry = new_entry;
+ ht->used_entries++;
+ return 0;
+ }
+ /* Change value if key already exists. */
+ if (ht->t[bucket + i].entry.key == key) {
+ ht->t[bucket + i].entry.value = value;
+ return 0;
+ }
+ }
+
+ return -ENOSPC; /* No space in bucket. */
+}
+
+/**
+ * Remove a key from an existing hash table. This operation is not multi-thread
+ * safe and should only be called from one thread.
+ *
+ * @param ht
+ * Hash table to remove the key from.
+ * @param key
+ * Key to remove from the hash table.
+ * @return
+ * 0 if ok, or negative value on error.
+ */
+static inline int
+rte_fbk_hash_delete_key(struct rte_fbk_hash_table *ht, uint32_t key)
+{
+ const uint32_t bucket = rte_fbk_hash_get_bucket(ht, key);
+ uint32_t last_entry = ht->entries_per_bucket - 1;
+ uint32_t i, j;
+
+ for (i = 0; i < ht->entries_per_bucket; i++) {
+ if (ht->t[bucket + i].entry.key == key) {
+ /* Find last key in bucket. */
+ for (j = ht->entries_per_bucket - 1; j > i; j-- ) {
+ if (! ht->t[bucket + j].entry.is_entry) {
+ last_entry = j - 1;
+ }
+ }
+ /*
+ * Move the last key to the deleted key's position, and
+ * delete the last key. lastEntry and i may be same but
+ * it doesn't matter.
+ */
+ ht->t[bucket + i].whole_entry =
+ ht->t[bucket + last_entry].whole_entry;
+ ht->t[bucket + last_entry].whole_entry = 0;
+
+ ht->used_entries--;
+ return 0;
+ }
+ }
+
+ return -ENOENT; /* Key didn't exist. */
+}
+
+/**
+ * Find a key in the hash table. This operation is multi-thread safe.
+ *
+ * @param ht
+ * Hash table to look in.
+ * @param key
+ * Key to find.
+ * @return
+ * The value that was associated with the key, or negative value on error.
+ */
+static inline int
+rte_fbk_hash_lookup(const struct rte_fbk_hash_table *ht, uint32_t key)
+{
+ const uint32_t bucket = rte_fbk_hash_get_bucket(ht, key);
+ union rte_fbk_hash_entry current_entry;
+ uint32_t i;
+
+ for (i = 0; i < ht->entries_per_bucket; i++) {
+ /* Single read of entry, which should be atomic. */
+ current_entry.whole_entry = ht->t[bucket + i].whole_entry;
+ if (! current_entry.entry.is_entry) {
+ return -ENOENT; /* Error once we hit an empty field. */
+ }
+ if (current_entry.entry.key == key) {
+ return current_entry.entry.value;
+ }
+ }
+ return -ENOENT; /* Key didn't exist. */
+}
+
+/**
+ * Delete all entries in a hash table. This operation is not multi-thread
+ * safe and should only be called from one thread.
+ *
+ * @param ht
+ * Hash table to delete entries in.
+ */
+static inline void
+rte_fbk_hash_clear_all(struct rte_fbk_hash_table *ht)
+{
+ memset(ht->t, 0, sizeof(ht->t[0]) * ht->entries);
+ ht->used_entries = 0;
+}
+
+/**
+ * Find what fraction of entries are being used.
+ *
+ * @param ht
+ * Hash table to find how many entries are being used in.
+ * @return
+ * Load factor of the hash table, or negative value on error.
+ */
+static inline double
+rte_fbk_hash_get_load_factor(struct rte_fbk_hash_table *ht)
+{
+ return (double)ht->used_entries / (double)ht->entries;
+}
+
+/**
+ * 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 with rte_errno
+ * set appropriately. Possible rte_errno values include:
+ * - ENOENT - required entry not available to return.
+ */
+struct rte_fbk_hash_table *rte_fbk_hash_find_existing(const char *name);
+
+/**
+ * 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 with rte_errno set appropriately.
+ * Possible rte_errno error values include:
+ * - E_RTE_NO_CONFIG - function could not get pointer to rte_config structure
+ * - E_RTE_SECONDARY - function was called from a secondary process instance
+ * - E_RTE_NO_TAILQ - no tailq list could be got for the fbk hash table list
+ * - EINVAL - invalid parameter value passed to function
+ * - ENOSPC - the maximum number of memzones has already been allocated
+ * - EEXIST - a memzone with the same name already exists
+ * - ENOMEM - no appropriate memory area found in which to create memzone
+ */
+struct rte_fbk_hash_table * \
+rte_fbk_hash_create(const struct rte_fbk_hash_params *params);
+
+/**
+ * Free all memory used by a hash table.
+ * Has no effect on hash tables allocated in memory zones
+ *
+ * @param ht
+ * Hash table to deallocate.
+ */
+void rte_fbk_hash_free(struct rte_fbk_hash_table *ht);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _RTE_FBK_HASH_H_ */