rte_thash.h File Reference

#include <stdint.h>
#include <rte_byteorder.h>
#include <rte_ip.h>
#include <rte_common.h>
#include <rte_thash_gfni.h>

Go to the source code of this file.

Data Structures
struct	rte_ipv4_tuple
struct	rte_ipv6_tuple

Macros
#define	RTE_THASH_V4_L3_LEN
#define	RTE_THASH_V4_L4_LEN   ((sizeof(struct rte_ipv4_tuple)) / 4)
#define	RTE_THASH_V6_L3_LEN
#define	RTE_THASH_V6_L4_LEN   ((sizeof(struct rte_ipv6_tuple)) / 4)
#define	RTE_THASH_IGNORE_PERIOD_OVERFLOW   0x1
#define	RTE_THASH_MINIMAL_SEQ   0x2

Typedefs
typedef int(*	rte_thash_check_tuple_t) (void *userdata, uint8_t *tuple)

Functions
static void	rte_convert_rss_key (const uint32_t *orig, uint32_t *targ, int len)
static void	rte_thash_load_v6_addrs (const struct rte_ipv6_hdr *orig, union rte_thash_tuple *targ)
static uint32_t	rte_softrss (uint32_t *input_tuple, uint32_t input_len, const uint8_t *rss_key)
static uint32_t	rte_softrss_be (uint32_t *input_tuple, uint32_t input_len, const uint8_t *rss_key)
int	rte_thash_gfni_supported (void)
void	rte_thash_complete_matrix (uint64_t *matrixes, const uint8_t *rss_key, int size)
struct rte_thash_ctx *	rte_thash_init_ctx (const char *name, uint32_t key_len, uint32_t reta_sz, uint8_t *key, uint32_t flags)
struct rte_thash_ctx *	rte_thash_find_existing (const char *name)
void	rte_thash_free_ctx (struct rte_thash_ctx *ctx)
int	rte_thash_add_helper (struct rte_thash_ctx *ctx, const char *name, uint32_t len, uint32_t offset)
struct rte_thash_subtuple_helper *	rte_thash_get_helper (struct rte_thash_ctx *ctx, const char *name)
uint32_t	rte_thash_get_complement (struct rte_thash_subtuple_helper *h, uint32_t hash, uint32_t desired_hash)
const uint8_t *	rte_thash_get_key (struct rte_thash_ctx *ctx)
const uint64_t *	rte_thash_get_gfni_matrices (struct rte_thash_ctx *ctx)
int	rte_thash_adjust_tuple (struct rte_thash_ctx *ctx, struct rte_thash_subtuple_helper *h, uint8_t *tuple, unsigned int tuple_len, uint32_t desired_value, unsigned int attempts, rte_thash_check_tuple_t fn, void *userdata)
__rte_experimental int	rte_thash_gen_key (uint8_t *key, size_t key_len, size_t reta_sz_log, uint32_t entropy_start, size_t entropy_sz)

Detailed Description

Software implementation of the Toeplitz hash function used by RSS. Can be used either for packet distribution on single queue NIC or for simulating of RSS computation on specific NIC (for example after GRE header decapsulating)

Definition in file rte_thash.h.

Macro Definition Documentation

RTE_THASH_V4_L3_LEN

#define RTE_THASH_V4_L3_LEN

Value:

((sizeof(struct rte_ipv4_tuple) -   \
            sizeof(((struct rte_ipv4_tuple *)0)->sctp_tag)) / 4)

length in dwords of input tuple to calculate hash of ipv4 header only

Definition at line 45 of file rte_thash.h.

RTE_THASH_V4_L4_LEN

#define RTE_THASH_V4_L4_LEN   ((sizeof(struct rte_ipv4_tuple)) / 4)

length in dwords of input tuple to calculate hash of ipv4 header + transport header

Definition at line 53 of file rte_thash.h.

RTE_THASH_V6_L3_LEN

#define RTE_THASH_V6_L3_LEN

Value:

((sizeof(struct rte_ipv6_tuple) -       \
            sizeof(((struct rte_ipv6_tuple *)0)->sctp_tag)) / 4)

length in dwords of input tuple to calculate hash of ipv6 header only

Definition at line 59 of file rte_thash.h.

RTE_THASH_V6_L4_LEN

#define RTE_THASH_V6_L4_LEN   ((sizeof(struct rte_ipv6_tuple)) / 4)

length in dwords of input tuple to calculate hash of ipv6 header + transport header

Definition at line 67 of file rte_thash.h.

RTE_THASH_IGNORE_PERIOD_OVERFLOW

#define RTE_THASH_IGNORE_PERIOD_OVERFLOW   0x1

LFSR will ignore if generated m-sequence has more than 2^n -1 bits, where n is the logarithm of the RSS ReTa size.

Definition at line 269 of file rte_thash.h.

RTE_THASH_MINIMAL_SEQ

#define RTE_THASH_MINIMAL_SEQ   0x2

Generate minimal required bit (equal to ReTa LSB) sequence into the hash_key

Definition at line 274 of file rte_thash.h.

Typedef Documentation

rte_thash_check_tuple_t

typedef int(* rte_thash_check_tuple_t) (void *userdata, uint8_t *tuple)

Function prototype for the rte_thash_adjust_tuple to check if adjusted tuple could be used. Generally it is some kind of lookup function to check if adjusted tuple is already in use.

Parameters

userdata	Pointer to the userdata. It could be a pointer to the table with used tuples to search.
tuple	Pointer to the tuple to check

Returns

1 on success 0 otherwise

Definition at line 428 of file rte_thash.h.

Function Documentation

rte_convert_rss_key()

static void rte_convert_rss_key ( const uint32_t *  orig, uint32_t *  targ, int  len  )

inlinestatic

Prepare special converted key to use with rte_softrss_be()

Parameters

orig	pointer to original RSS key
targ	pointer to target RSS key
len	RSS key length

Definition at line 134 of file rte_thash.h.

rte_thash_load_v6_addrs()

static void rte_thash_load_v6_addrs ( const struct rte_ipv6_hdr *  orig, union rte_thash_tuple *  targ  )

inlinestatic

Prepare and load IPv6 addresses (src and dst) into target tuple

Parameters

orig	Pointer to ipv6 header of the original packet
targ	Pointer to rte_ipv6_tuple structure

Definition at line 151 of file rte_thash.h.

rte_softrss()

static uint32_t rte_softrss ( uint32_t *  input_tuple, uint32_t  input_len, const uint8_t *  rss_key  )

inlinestatic

Generic implementation. Can be used with original rss_key

Parameters

input_tuple	Pointer to input tuple
input_len	Length of input_tuple in 4-bytes chunks
rss_key	Pointer to RSS hash key.

Returns

Calculated hash value.

Definition at line 189 of file rte_thash.h.

rte_softrss_be()

static uint32_t rte_softrss_be ( uint32_t *  input_tuple, uint32_t  input_len, const uint8_t *  rss_key  )

inlinestatic

Optimized implementation. If you want the calculated hash value matches NIC RSS value you have to use special converted key with rte_convert_rss_key() fn.

Parameters

input_tuple	Pointer to input tuple
input_len	Length of input_tuple in 4-bytes chunks
*rss_key	Pointer to RSS hash key.

Returns

Calculated hash value.

Definition at line 219 of file rte_thash.h.

rte_thash_gfni_supported()

int rte_thash_gfni_supported

(

void

)

Indicates if GFNI implementations of the Toeplitz hash are supported.

Returns

1 if GFNI is supported 0 otherwise

rte_thash_complete_matrix()

void rte_thash_complete_matrix	(	uint64_t *	matrixes,
		const uint8_t *	rss_key,
		int	size
	)

Converts Toeplitz hash key (RSS key) into matrixes required for GFNI implementation

Parameters

matrixes	pointer to the memory where matrices will be written. Note: the size of this memory must be equal to size * 8
rss_key	pointer to the Toeplitz hash key
size	Size of the rss_key in bytes.

rte_thash_init_ctx()

struct rte_thash_ctx* rte_thash_init_ctx	(	const char *	name,
		uint32_t	key_len,
		uint32_t	reta_sz,
		uint8_t *	key,
		uint32_t	flags
	)

Create a new thash context.

Parameters

name	Context name
key_len	Length of the toeplitz hash key
reta_sz	Logarithm of the NIC's Redirection Table (ReTa) size, i.e. number of the LSBs if the hash used to determine the reta entry.
key	Pointer to the key used to init an internal key state. Could be NULL, in this case internal key will be inited with random.
flags	Supported flags are: RTE_THASH_IGNORE_PERIOD_OVERFLOW RTE_THASH_MINIMAL_SEQ

Returns

A pointer to the created context on success NULL otherwise

rte_thash_find_existing()

struct rte_thash_ctx* rte_thash_find_existing

(

const char *

name

)

Find an existing thash context and return a pointer to it.

Parameters

name	Name of the thash context

Returns

Pointer to the thash context or NULL if it was not found with rte_errno set appropriately. Possible rte_errno values include:

• ENOENT - required entry not available to return.

rte_thash_free_ctx()

void rte_thash_free_ctx

(

struct rte_thash_ctx *

ctx

)

Free a thash context object

Parameters

ctx	Thash context

rte_thash_add_helper()

int rte_thash_add_helper	(	struct rte_thash_ctx *	ctx,
		const char *	name,
		uint32_t	len,
		uint32_t	offset
	)

Add a special properties to the toeplitz hash key inside a thash context. Creates an internal helper struct which has a complementary table to calculate toeplitz hash collisions. This function is not multi-thread safe.

Parameters

ctx	Thash context
name	Name of the helper
len	Length in bits of the target subtuple Must be no shorter than reta_sz passed on rte_thash_init_ctx().
offset	Offset in bits of the subtuple

Returns

0 on success negative on error

rte_thash_get_helper()

struct rte_thash_subtuple_helper* rte_thash_get_helper	(	struct rte_thash_ctx *	ctx,
		const char *	name
	)

Find a helper in the context by the given name

Parameters

ctx	Thash context
name	Name of the helper

Returns

Pointer to the thash helper or NULL if it was not found.

rte_thash_get_complement()

uint32_t rte_thash_get_complement	(	struct rte_thash_subtuple_helper *	h,
		uint32_t	hash,
		uint32_t	desired_hash
	)

Get a complementary value for the subtuple to produce a partial toeplitz hash collision. It must be XOR'ed with the subtuple to produce the hash value with the desired hash LSB's This function is multi-thread safe.

Parameters

h	Pointer to the helper struct
hash	Toeplitz hash value calculated for the given tuple
desired_hash	Desired hash value to find a collision for

Returns

A complementary value which must be xored with the corresponding subtuple

rte_thash_get_key()

const uint8_t* rte_thash_get_key

(

struct rte_thash_ctx *

ctx

)

Get a pointer to the toeplitz hash contained in the context. It changes after each addition of a helper. It should be installed to the NIC.

Parameters

ctx	Thash context

Returns

A pointer to the toeplitz hash key

rte_thash_get_gfni_matrices()

const uint64_t* rte_thash_get_gfni_matrices

(

struct rte_thash_ctx *

ctx

)

Get a pointer to the toeplitz hash matrices contained in the context. These matrices could be used with fast toeplitz hash implementation if CPU supports GFNI. Matrices changes after each addition of a helper.

Parameters

ctx	Thash context

Returns

A pointer to the toeplitz hash key matrices on success NULL if GFNI is not supported.

rte_thash_adjust_tuple()

int rte_thash_adjust_tuple	(	struct rte_thash_ctx *	ctx,
		struct rte_thash_subtuple_helper *	h,
		uint8_t *	tuple,
		unsigned int	tuple_len,
		uint32_t	desired_value,
		unsigned int	attempts,
		rte_thash_check_tuple_t	fn,
		void *	userdata
	)

Adjusts tuple in the way to make Toeplitz hash has desired least significant bits. This function is multi-thread safe.

Parameters

ctx	Thash context
h	Pointer to the helper struct
tuple	Pointer to the tuple to be adjusted
tuple_len	Length of the tuple. Must be multiple of 4.
desired_value	Desired value of least significant bits of the hash
attempts	Number of attempts to adjust tuple with fn() calling
fn	Callback function to check adjusted tuple. Could be NULL
userdata	Pointer to the userdata to be passed to fn(). Could be NULL

Returns

0 on success negative otherwise

rte_thash_gen_key()

__rte_experimental int rte_thash_gen_key	(	uint8_t *	key,
		size_t	key_len,
		size_t	reta_sz_log,
		uint32_t	entropy_start,
		size_t	entropy_sz
	)

Warning

EXPERIMENTAL: this API may change without prior notice.

Modify RSS hash key such that subtuple bits corresponding to entropy_sz bits starting from entropy_start will have the most even distribution with this key with a given ReTa size.

Parameters

key	Pointer to the RSS hash key.
key_len	Length of the key.
reta_sz_log	Log2 of the size of RSS redirection table, i.e. number of bits of the RSS hash value used to identify RSS ReTa entry.
entropy_start	Bit offset from the beginning of the tuple where user expects best distribution of the subtuple values.
entropy_sz	Size in bits of the part of subtuple.

Returns

0 on success negative otherwise