zephyr中net

1、相关数据结构说明：

数据结构如下：

struct net_buf { union { int _unused; struct net_buf *frags; }; uint8_t ref; uint8_t flags; struct net_buf_pool *pool; union { struct { uint8_t *data; uint16_t len; uint16_t size; }; struct net_buf_simple b; }; uint8_t __buf[0] __net_buf_align; }; struct net_buf_pool { struct k_lifo free; // LIFO to place the buffer into when free const uint16_t buf_count; uint16_t uninit_count; const uint16_t buf_size; const uint16_t user_data_size; void (*const destroy)(struct net_buf *buf); struct net_buf * const __bufs; }; #define SYS_DLIST_STATIC_INIT(ptr_to_list) {{(ptr_to_list)}, {(ptr_to_list)}} #define K_LIFO_INITIALIZER(obj) \ { \ .wait_q = SYS_DLIST_STATIC_INIT(&obj.wait_q), \ .list = NULL, \ _OBJECT_TRACING_INIT \ } #define NET_BUF_POOL_INITIALIZER(_pool, _bufs, _count, _size, _ud_size, \ _destroy) \ { \ .free = K_LIFO_INITIALIZER(_pool.free), \ .__bufs = (struct net_buf *)_bufs, \ .buf_count = _count, \ .uninit_count = _count, \ .buf_size = _size, \ .user_data_size = _ud_size, \ .destroy = _destroy, \ } #define NET_BUF_POOL_DEFINE(_name, _count, _size, _ud_size, _destroy) \ static struct { \ struct net_buf buf; \ uint8_t data[_size] __net_buf_align; \ uint8_t ud[ROUND_UP(_ud_size, 4)] __net_buf_align; \ } _net_buf_pool_##_name[_count] __noinit; \ static struct net_buf_pool _name = \ NET_BUF_POOL_INITIALIZER(_name, _net_buf_pool_##_name, \ _count, _size, _ud_size, _destroy)

用以上的定义，来声明几个变量，用一个宏来搞定

NET_BUF_POOL_DEFINE(bufs_pool, 22, 74, 6, buf_destroy);

这个宏展开后如下

static struct { struct net_buf buf; uint8_t data[74] __net_buf_align; uint8_t ud[ROUND_UP(6, 4)] __net_buf_align; } _net_buf_pool_bufs_pool[22] __noinit; static struct net_buf_pool bufs_pool = { .free = { .wait_q = {{(&bufs_pool.free.wait_q)}, {(&bufs_pool.free.wait_q)}}, .list = NULL, _OBJECT_TRACING_INIT //与这个结构没有关系，就先不展开这个宏定义了 }, .__bufs = (struct net_buf *)_net_buf_pool_bufs_pool, .buf_count = 22, .uninit_count = 22, .buf_size = 74, .user_data_size = 6, .destroy = buf_destroy, }

相当于定义了一个数组_net_buf_pool_bufs_pool[22] 和一个变量bufs_pool.

bufs_pool用来描述一个buffer池的，即这个buffer池有多少个buffer，用了多少个，首地址在什么地方，释放和销毁的函数是什么，每个buffer的大小等信息。

net_buf_pool_bufs_pool[22] 是具体的buffer池子，bufs_pool实际上是用来描述这个池子的。

2、补充： (lifo在\kernel\lifo.c中定义和实现相关的函数) 补充罗列不太相关的结构定义，在前面有用到了，实际上是一个双向链表：

struct _dnode { union { struct _dnode *head; /* ptr to head of list (sys_dlist_t) */ struct _dnode *next; /* ptr to next node (sys_dnode_t) */ }; union { struct _dnode *tail; /* ptr to tail of list (sys_dlist_t) */ struct _dnode *prev; /* ptr to previous node (sys_dnode_t) */ }; }; typedef struct _dnode sys_dlist_t; typedef sys_dlist_t _wait_q_t; struct k_lifo { _wait_q_t wait_q; void *list; _OBJECT_TRACING_NEXT_PTR(k_lifo); };