vpp 处理数据报文 hash table 代码

以下是使用 VPP 处理数据报文的哈希表（hash table）代码示例：

#include <vppinfra/hash.h>

typedef struct {
    u32 key;
    u32 value;
} my_hash_entry_t;

typedef struct {
    u32 *buckets;
    my_hash_entry_t *entries;
    u32 num_buckets;
    u32 num_entries;
} my_hash_table_t;

static void
my_hash_table_init (my_hash_table_t * ht, u32 num_buckets, u32 num_entries)
{
    clib_memset (ht, 0, sizeof (*ht));
    ht->num_buckets = num_buckets;
    vec_validate (ht->buckets, num_buckets - 1);
    ht->num_entries = num_entries;
    vec_resize (ht->entries, num_entries);
}

static u32
my_hash_table_lookup (my_hash_table_t * ht, u32 key)
{
    u32 bucket_index = key & (ht->num_buckets - 1);
    u32 entry_index = ht->buckets[bucket_index];

    while (entry_index != ~0)
    {
        if (ht->entries[entry_index].key == key)
            return ht->entries[entry_index].value;

        entry_index = ht->entries[entry_index].next_index;
    }

    return ~0;
}

static void
my_hash_table_add (my_hash_table_t * ht, u32 key, u32 value)
{
    u32 bucket_index = key & (ht->num_buckets - 1);
    u32 entry_index = ht->buckets[bucket_index];

    while (entry_index != ~0)
    {
        if (ht->entries[entry_index].key == key)
        {
            ht->entries[entry_index].value = value;
            return;
        }

        entry_index = ht->entries[entry_index].next_index;
    }

    entry_index = ht->entries - ht->entries;

    ht->entries[entry_index].key = key;
    ht->entries[entry_index].value = value;
    ht->entries[entry_index].next_index = ht->buckets[bucket_index];
    ht->buckets[bucket_index] = entry_index;
}

上述代码使用 VPP 的哈希表（hash table）实现了查找和添加操作。哈希表的初始化使用 my_hash_table_init 函数，接收哈希表、桶的数量和条目数量作为参数。哈希表查找使用 my_hash_table_lookup 函数，接收哈希表和要查找的键作为参数。哈希表添加使用 my_hash_table_add 函数，接收哈希表、键和值作为参数。