structpbuf *pbuf_alloc (pbuf_layer layer, u16_t length, pbuf_type type)structpbuf * pbuf_alloc_reference (void*payload, u16_t length, pbuf_type type)structpbuf * pbuf_alloced_custom (pbuf_layer l, u16_t length, pbuf_type type,structpbuf_custom *p,void*payload_mem, u16_t payload_mem...
通过pbuf_alloc()创建一个pbuf,要创建一个pbuf,需要知道三个参数: 1,这个pbuf所在的网络层,以此来确定offset的值,上层的offset不仅要为自己的首部留出空间,而且还需要为下层的首部留出空间,所以层级越高,offset越大。 2,存放数据的大小 3,pbuf的类型 代码如下,参考注释和第二节的各种类型的示意图,理解代码逻辑 /...
*/2526/**27* the reference count always equals the number of pointers28* that refer to this pbuf. This can be pointers from an application29* the stack itself, or pbuf->next pointers from a chain.30*/31u16_tref;/*表示该pbuf被引用的次数,初始化一个pbuf的时候,ref字段值被设置为1*/32/...
... } I have completely fixed this code by using pbuf_copy() to create my own pbuf which i can modify all i want without causing any troubles to TCP stack. I don't call pbuf_ref() on original packet, because i don't reference original pbuf anymore. //Alloc with 4 additional bytes...
room for IP layer header */ offset = PBUF_LINK_HLEN + PBUF_IP_HLEN;break;case PBUF_LINK:/* add room for link layer header */ offset = PBUF_LINK_HLEN;break;case PBUF_RAW:offset = 0;break;default:LWIP_ASSERT("pbuf_alloc: bad pbuf layer", 0);return NULL;} switch (type) { ...
netbuf_new用于分配一个新的netbuf结构,注意这里只是一个头部结构,而真正需要的存储数据区域是在函数netbuf_alloc 中分配的,同理函数netbuf_delete用于删除一个netbuf结构,同时函数pbuf_free会被调用,用以删除数据区域的空间。 以上这几个函数使用的简单例子如下: ...
LWIP_ASSERT("pbuf_alloc: erroneous type", 0); return NULL; } /* set reference count */ p->ref = 1; /* set flags */ p->flags = 0; return p; } 4、pbuf_free u8_t pbuf_free(struct pbuf *p) { u16_t type; struct pbuf *q; ...
(MEMP_PBUF_POOL);/* 为PBUF_POOL类型时 *//*PBUF_POOL类型和PBUF_RAM类型的都由内存池分配得到,此处调用了memp_malloc,在memp.c文件中 *//* 分配的内存池类型为MEMP_PBUF_POOL*/LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_alloc: allocated pbuf %p\n"), (void *)p));/* p是pbuf类型...
1p = memp_alloc(MEMP_PBUF);//在内存池中分配一个相应的pbuf结构头,而不申请数据区的空间。 PBUF_ROM指向ROM空间内的某段数据 4)PBUF_REF内存申请: 1p = memp_malloc(MEMP_PBUF);//在内存池中分配一个相应的pbuf结构头,而不申请数据区的空间