rte_lpm.h

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/* SPDX-License-Identifier: BSD-3-Clause
 * Copyright(c) 2010-2014 Intel Corporation
 * Copyright(c) 2020 Arm Limited
 */

#ifndef _RTE_LPM_H_
#define _RTE_LPM_H_

#include <errno.h>
#include <stdalign.h>
#include <stdint.h>

#include <rte_branch_prediction.h>
#include <rte_byteorder.h>
#include <rte_common.h>
#include <rte_vect.h>
#include <rte_rcu_qsbr.h>

#ifdef __cplusplus
extern "C" {
#endif

#define RTE_LPM_NAMESIZE                32

#define RTE_LPM_MAX_DEPTH               32

#define RTE_LPM_TBL24_NUM_ENTRIES       (1 << 24)

#define RTE_LPM_TBL8_GROUP_NUM_ENTRIES  256

#define RTE_LPM_MAX_TBL8_NUM_GROUPS         (1 << 24)

#define RTE_LPM_TBL8_NUM_GROUPS         256

#define RTE_LPM_TBL8_NUM_ENTRIES        (RTE_LPM_TBL8_NUM_GROUPS * \
                    RTE_LPM_TBL8_GROUP_NUM_ENTRIES)

#if defined(RTE_LIBRTE_LPM_DEBUG)
#define RTE_LPM_RETURN_IF_TRUE(cond, retval) do { \
    if (cond) return (retval);                \
} while (0)
#else
#define RTE_LPM_RETURN_IF_TRUE(cond, retval)
#endif

#define RTE_LPM_VALID_EXT_ENTRY_BITMASK 0x03000000

#define RTE_LPM_LOOKUP_SUCCESS          0x01000000

#define RTE_LPM_RCU_DQ_RECLAIM_MAX  16

enum rte_lpm_qsbr_mode {
    RTE_LPM_QSBR_MODE_DQ = 0,
    RTE_LPM_QSBR_MODE_SYNC
};

#if RTE_BYTE_ORDER == RTE_LITTLE_ENDIAN

__extension__
struct rte_lpm_tbl_entry {
    union {
        RTE_ATOMIC(uint32_t) val;
        struct {
            uint32_t next_hop    :24;
            /* Using single uint8_t to store 3 values. */
            uint32_t valid       :1;   
            uint32_t valid_group :1;
            uint32_t depth       :6; 
        };
    };
};

#else

__extension__
struct rte_lpm_tbl_entry {
    union {
        RTE_ATOMIC(uint32_t) val;
        struct {
            uint32_t depth       :6;
            uint32_t valid_group :1;
            uint32_t valid       :1;
            uint32_t next_hop    :24;
        };
    };
};

#endif

static_assert(sizeof(struct rte_lpm_tbl_entry) == sizeof(uint32_t),
        "sizeof(struct rte_lpm_tbl_entry) == sizeof(uint32_t)");

struct rte_lpm_config {
    uint32_t max_rules;      
    uint32_t number_tbl8s;   
    int flags;               
};

struct rte_lpm {
    /* LPM Tables. */
    alignas(RTE_CACHE_LINE_SIZE) struct rte_lpm_tbl_entry tbl24[RTE_LPM_TBL24_NUM_ENTRIES];
    struct rte_lpm_tbl_entry *tbl8; 
};

struct rte_lpm_rcu_config {
    struct rte_rcu_qsbr *v; /* RCU QSBR variable. */
    /* Mode of RCU QSBR. RTE_LPM_QSBR_MODE_xxx
     * '0' for default: create defer queue for reclaim.
     */
    enum rte_lpm_qsbr_mode mode;
    uint32_t dq_size;   /* RCU defer queue size.
                 * default: lpm->number_tbl8s.
                 */
    uint32_t reclaim_thd;   /* Threshold to trigger auto reclaim. */
    uint32_t reclaim_max;   /* Max entries to reclaim in one go.
                 * default: RTE_LPM_RCU_DQ_RECLAIM_MAX.
                 */
};

void
rte_lpm_free(struct rte_lpm *lpm);

struct rte_lpm *
rte_lpm_create(const char *name, int socket_id,
           const struct rte_lpm_config *config)
    __rte_malloc __rte_dealloc(rte_lpm_free, 1);

struct rte_lpm *
rte_lpm_find_existing(const char *name);

int rte_lpm_rcu_qsbr_add(struct rte_lpm *lpm, struct rte_lpm_rcu_config *cfg);

int
rte_lpm_add(struct rte_lpm *lpm, uint32_t ip, uint8_t depth, uint32_t next_hop);

int
rte_lpm_is_rule_present(struct rte_lpm *lpm, uint32_t ip, uint8_t depth,
uint32_t *next_hop);

int
rte_lpm_delete(struct rte_lpm *lpm, uint32_t ip, uint8_t depth);

void
rte_lpm_delete_all(struct rte_lpm *lpm);

static inline int
rte_lpm_lookup(const struct rte_lpm *lpm, uint32_t ip, uint32_t *next_hop)
{
    unsigned tbl24_index = (ip >> 8);
    uint32_t tbl_entry;
    const uint32_t *ptbl;

    /* DEBUG: Check user input arguments. */
    RTE_LPM_RETURN_IF_TRUE(((lpm == NULL) || (next_hop == NULL)), -EINVAL);

    /* Copy tbl24 entry */
    ptbl = (const uint32_t *)(&lpm->tbl24[tbl24_index]);
    tbl_entry = *ptbl;

    /* Memory ordering is not required in lookup. Because dataflow
     * dependency exists, compiler or HW won't be able to re-order
     * the operations.
     */
    /* Copy tbl8 entry (only if needed) */
    if (unlikely((tbl_entry & RTE_LPM_VALID_EXT_ENTRY_BITMASK) ==
            RTE_LPM_VALID_EXT_ENTRY_BITMASK)) {

        unsigned tbl8_index = (uint8_t)ip +
                (((uint32_t)tbl_entry & 0x00FFFFFF) *
                        RTE_LPM_TBL8_GROUP_NUM_ENTRIES);

        ptbl = (const uint32_t *)&lpm->tbl8[tbl8_index];
        tbl_entry = *ptbl;
    }

    *next_hop = ((uint32_t)tbl_entry & 0x00FFFFFF);
    return (tbl_entry & RTE_LPM_LOOKUP_SUCCESS) ? 0 : -ENOENT;
}

#define rte_lpm_lookup_bulk(lpm, ips, next_hops, n) \
        rte_lpm_lookup_bulk_func(lpm, ips, next_hops, n)

static inline int
rte_lpm_lookup_bulk_func(const struct rte_lpm *lpm, const uint32_t *ips,
        uint32_t *next_hops, const unsigned n)
{
    unsigned i;
    const uint32_t *ptbl;

    /* DEBUG: Check user input arguments. */
    RTE_LPM_RETURN_IF_TRUE(((lpm == NULL) || (ips == NULL) ||
            (next_hops == NULL)), -EINVAL);

    for (i = 0; i < n; i++) {
        unsigned int tbl24_index = ips[i] >> 8;

        /* Simply copy tbl24 entry to output */
        ptbl = (const uint32_t *)&lpm->tbl24[tbl24_index];
        next_hops[i] = *ptbl;

        /* Overwrite output with tbl8 entry if needed */
        if (unlikely((next_hops[i] & RTE_LPM_VALID_EXT_ENTRY_BITMASK) ==
                RTE_LPM_VALID_EXT_ENTRY_BITMASK)) {

            unsigned tbl8_index = (uint8_t)ips[i] +
                    (((uint32_t)next_hops[i] & 0x00FFFFFF) *
                     RTE_LPM_TBL8_GROUP_NUM_ENTRIES);

            ptbl = (const uint32_t *)&lpm->tbl8[tbl8_index];
            next_hops[i] = *ptbl;
        }
    }
    return 0;
}

/* Mask four results. */
#define  RTE_LPM_MASKX4_RES UINT64_C(0x00ffffff00ffffff)

static inline void
rte_lpm_lookupx4(const struct rte_lpm *lpm, xmm_t ip, uint32_t hop[4],
    uint32_t defv);

#ifdef __cplusplus
}
#endif

#if defined(RTE_ARCH_ARM)
#ifdef RTE_HAS_SVE_ACLE
#include "rte_lpm_sve.h"
#undef rte_lpm_lookup_bulk
#define rte_lpm_lookup_bulk(lpm, ips, next_hops, n) \
        __rte_lpm_lookup_vec(lpm, ips, next_hops, n)
#endif
#include "rte_lpm_neon.h"
#elif defined(RTE_ARCH_PPC_64)
#include "rte_lpm_altivec.h"
#elif defined(RTE_ARCH_X86)
#include "rte_lpm_sse.h"
#elif defined(RTE_ARCH_RISCV) && defined(RTE_RISCV_FEATURE_V)
#include "rte_lpm_rvv.h"
#else
#include "rte_lpm_scalar.h"
#endif

#endif /* _RTE_LPM_H_ */