--- name: "rte_fbk_hash_lookup" section: "3" platform: "linux" package: "dpdk-doc" version: "24.11.4-0+deb13u1" release: "Debian 13 (Trixie)" platforms: ["linux"] url: "https://new.carta.tech/rte_fbk_hash.h" --- # rte\_fbk\_hash\_lookup(3) Part of [rte\_fbk\_hash.h(3)](/rte_fbk_hash.h/3.md). ## NAME rte\_fbk\_hash.h ## SYNOPSIS `#include `\ `#include `\ `#include `\ `#include `\ `#include `\ ### Data Structures struct **rte\_fbk\_hash\_params**\ union **rte\_fbk\_hash\_entry**\ struct **rte\_fbk\_hash\_table**\ ### Macros \#define **RTE\_FBK\_HASH\_INIT\_VAL\_DEFAULT** 0xFFFFFFFF\ \#define **RTE\_FBK\_HASH\_ENTRIES\_MAX** (1 \<\< 20)\ \#define **RTE\_FBK\_HASH\_ENTRIES\_PER\_BUCKET\_MAX** 256\ \#define **RTE\_FBK\_HASH\_NAMESIZE** 32\ ### Typedefs **typedef** uint32\_t(\* **rte\_fbk\_hash\_fn**) (uint32\_t key, uint32\_t init\_val)\ ### Functions static uint32\_t **rte\_fbk\_hash\_get\_bucket** (const struct **rte\_fbk\_hash\_table** \*ht, uint32\_t key)\ static int **rte\_fbk\_hash\_add\_key\_with\_bucket** (struct **rte\_fbk\_hash\_table** \*ht, uint32\_t key, uint16\_t value, uint32\_t bucket)\ static int **rte\_fbk\_hash\_add\_key** (struct **rte\_fbk\_hash\_table** \*ht, uint32\_t key, uint16\_t value)\ static int **rte\_fbk\_hash\_delete\_key\_with\_bucket** (struct **rte\_fbk\_hash\_table** \*ht, uint32\_t key, uint32\_t bucket)\ static int **rte\_fbk\_hash\_delete\_key** (struct **rte\_fbk\_hash\_table** \*ht, uint32\_t key)\ static int **rte\_fbk\_hash\_lookup\_with\_bucket** (const struct **rte\_fbk\_hash\_table** \*ht, uint32\_t key, uint32\_t bucket)\ static int **rte\_fbk\_hash\_lookup** (const struct **rte\_fbk\_hash\_table** \*ht, uint32\_t key)\ static void **rte\_fbk\_hash\_clear\_all** (struct **rte\_fbk\_hash\_table** \*ht)\ static double **rte\_fbk\_hash\_get\_load\_factor** (struct **rte\_fbk\_hash\_table** \*ht)\ struct **rte\_fbk\_hash\_table** \* **rte\_fbk\_hash\_find\_existing** (const char \*name)\ struct **rte\_fbk\_hash\_table** \* **rte\_fbk\_hash\_create** (const struct **rte\_fbk\_hash\_params** \*params)\ void **rte\_fbk\_hash\_free** (struct **rte\_fbk\_hash\_table** \*ht)\ ## Detailed Description 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. Definition in file **rte\_fbk\_hash.h**. ## Macro Definition Documentation ### #define RTE\_FBK\_HASH\_INIT\_VAL\_DEFAULT 0xFFFFFFFF Initialising value used when calculating hash. Definition at line **32** of file **rte\_fbk\_hash.h**. ### #define RTE\_FBK\_HASH\_ENTRIES\_MAX (1 \<\< 20) The maximum number of entries in the hash table that is supported. Definition at line **36** of file **rte\_fbk\_hash.h**. ### #define RTE\_FBK\_HASH\_ENTRIES\_PER\_BUCKET\_MAX 256 The maximum number of entries in each bucket that is supported. Definition at line **39** of file **rte\_fbk\_hash.h**. ### #define RTE\_FBK\_HASH\_NAMESIZE 32 Maximum size of string for naming the hash. Definition at line **42** of file **rte\_fbk\_hash.h**. ## Typedef Documentation ### typedef uint32\_t(\* rte\_fbk\_hash\_fn) (uint32\_t key, uint32\_t init\_val) Type of function that can be used for calculating the hash value. Definition at line **45** of file **rte\_fbk\_hash.h**. ## Function Documentation ### static uint32\_t rte\_fbk\_hash\_get\_bucket (const struct rte\_fbk\_hash\_table \* ht, uint32\_t key)` [inline]`, ` [static]` Find the offset into hash table of the bucket containing a particular key. **Parameters** *ht* Pointer to hash table. \ *key* Key to calculate bucket for. **Returns** Offset into hash table. Definition at line **94** of file **rte\_fbk\_hash.h**. ### static int rte\_fbk\_hash\_add\_key\_with\_bucket (struct rte\_fbk\_hash\_table \* ht, uint32\_t key, uint16\_t value, uint32\_t bucket)` [inline]`, ` [static]` Add a key to an existing hash table with bucket id. This operation is not multi-thread safe and should only be called from one thread. **Parameters** *ht* Hash table to add the key to. \ *key* Key to add to the hash table. \ *value* Value to associate with key. \ *bucket* Bucket to associate with key. **Returns** 0 if ok, or negative value on error. Definition at line **117** of file **rte\_fbk\_hash.h**. ### static int rte\_fbk\_hash\_add\_key (struct rte\_fbk\_hash\_table \* ht, uint32\_t key, uint16\_t value)` [inline]`, ` [static]` Add a key to an existing hash table. This operation is not multi-thread safe and should only be called from one thread. **Parameters** *ht* Hash table to add the key to. \ *key* Key to add to the hash table. \ *value* Value to associate with key. **Returns** 0 if ok, or negative value on error. Definition at line **162** of file **rte\_fbk\_hash.h**. ### static int rte\_fbk\_hash\_delete\_key\_with\_bucket (struct rte\_fbk\_hash\_table \* ht, uint32\_t key, uint32\_t bucket)` [inline]`, ` [static]` Remove a key with a given bucket id from an existing hash table. This operation is not multi-thread safe and should only be called from one thread. **Parameters** *ht* Hash table to remove the key from. \ *key* Key to remove from the hash table. \ *bucket* Bucket id associate with key. **Returns** 0 if ok, or negative value on error. Definition at line **184** of file **rte\_fbk\_hash.h**. ### static int rte\_fbk\_hash\_delete\_key (struct rte\_fbk\_hash\_table \* ht, uint32\_t key)` [inline]`, ` [static]` Remove a key from an existing hash table. This operation is not multi-thread safe and should only be called from one thread. **Parameters** *ht* Hash table to remove the key from. \ *key* Key to remove from the hash table. **Returns** 0 if ok, or negative value on error. Definition at line **227** of file **rte\_fbk\_hash.h**. ### static int rte\_fbk\_hash\_lookup\_with\_bucket (const struct rte\_fbk\_hash\_table \* ht, uint32\_t key, uint32\_t bucket)` [inline]`, ` [static]` Find a key in the hash table with a given bucketid. This operation is multi-thread safe. **Parameters** *ht* Hash table to look in. \ *key* Key to find. \ *bucket* Bucket associate to the key. **Returns** The value that was associated with the key, or negative value on error. Definition at line **247** of file **rte\_fbk\_hash.h**. ### static int rte\_fbk\_hash\_lookup (const struct rte\_fbk\_hash\_table \* ht, uint32\_t key)` [inline]`, ` [static]` Find a key in the hash table. This operation is multi-thread safe. **Parameters** *ht* Hash table to look in. \ *key* Key to find. **Returns** The value that was associated with the key, or negative value on error. Definition at line **277** of file **rte\_fbk\_hash.h**. ### static void rte\_fbk\_hash\_clear\_all (struct rte\_fbk\_hash\_table \* ht)` [inline]`, ` [static]` Delete all entries in a hash table. This operation is not multi-thread safe and should only be called from one thread. **Parameters** *ht* Hash table to delete entries in. Definition at line **291** of file **rte\_fbk\_hash.h**. ### static double rte\_fbk\_hash\_get\_load\_factor (struct rte\_fbk\_hash\_table \* ht)` [inline]`, ` [static]` Find what fraction of entries are being used. **Parameters** *ht* Hash table to find how many entries are being used in. **Returns** Load factor of the hash table, or negative value on error. Definition at line **306** of file **rte\_fbk\_hash.h**. ### struct rte\_fbk\_hash\_table \* rte\_fbk\_hash\_find\_existing (const char \* name) Performs a lookup for an existing hash table, and returns a pointer to the table if found. **Parameters** *name* Name of the hash table to find **Returns** 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\_create (const struct rte\_fbk\_hash\_params \* params) Create a new hash table for use with four byte keys. **Parameters** *params* Parameters used in creation of hash table. **Returns** 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 - • 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 ### void rte\_fbk\_hash\_free (struct rte\_fbk\_hash\_table \* ht) Free all memory used by a hash table. Has no effect on hash tables allocated in memory zones **Parameters** *ht* Hash table to deallocate. ## Author Generated automatically by Doxygen for DPDK from the source code.