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

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)

__rte_experimental 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)

__rte_experimental struct rte_thash_ctx *	rte_thash_find_existing (const char *name)

__rte_experimental void	rte_thash_free_ctx (struct rte_thash_ctx *ctx)

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

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

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

__rte_experimental const uint8_t *	rte_thash_get_key (struct rte_thash_ctx *ctx)

__rte_experimental 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)

Detailed Description

toeplitz hash functions.

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)

rte_ipv4_tuple

Definition: rte_thash.h:76

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

Definition at line 48 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 56 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)

rte_ipv6_tuple

Definition: rte_thash.h:94

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

Definition at line 62 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 70 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 235 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 240 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.

Warning: EXPERIMENTAL: this API may change without prior notice.

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 409 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 126 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 143 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 181 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 211 of file rte_thash.h.

◆ rte_thash_init_ctx()

__rte_experimental 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.

Warning: EXPERIMENTAL: this API may change without prior notice.

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()

__rte_experimental struct rte_thash_ctx* rte_thash_find_existing ( const char * name )

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

Warning: EXPERIMENTAL: this API may change without prior notice.

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()

__rte_experimental void rte_thash_free_ctx ( struct rte_thash_ctx * ctx )

Free a thash context object

Warning: EXPERIMENTAL: this API may change without prior notice.

Parameters

ctx	Thash context

Returns: None

◆ rte_thash_add_helper()

__rte_experimental 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.

Warning: EXPERIMENTAL: this API may change without prior notice.

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()

__rte_experimental 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

Warning: EXPERIMENTAL: this API may change without prior notice.

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()

__rte_experimental 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()

__rte_experimental 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.

Warning: EXPERIMENTAL: this API may change without prior notice.

Parameters

ctx	Thash context

Returns: A pointer to the toeplitz hash key

◆ rte_thash_adjust_tuple()

__rte_experimental 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.

Warning: EXPERIMENTAL: this API may change without prior notice.

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

Data Structures

Macros

Typedefs

Functions

Detailed Description

Macro Definition Documentation

◆ RTE_THASH_V4_L3_LEN

◆ RTE_THASH_V4_L4_LEN

◆ RTE_THASH_V6_L3_LEN

◆ RTE_THASH_V6_L4_LEN

◆ RTE_THASH_IGNORE_PERIOD_OVERFLOW

◆ RTE_THASH_MINIMAL_SEQ

Typedef Documentation

◆ rte_thash_check_tuple_t

Function Documentation

◆ rte_convert_rss_key()

◆ rte_thash_load_v6_addrs()

◆ rte_softrss()

◆ rte_softrss_be()

◆ rte_thash_init_ctx()

◆ rte_thash_find_existing()

◆ rte_thash_free_ctx()

◆ rte_thash_add_helper()

◆ rte_thash_get_helper()

◆ rte_thash_get_complement()

◆ rte_thash_get_key()

◆ rte_thash_adjust_tuple()