const int offset)//{///这是把tail指针移到数据区的最后面//skb->tail = skb->data + offset;//}}//这是拆分分片结构数据区数据,同理,其他参数不变,参数:pos则是sk_buff结构数据区中有效数据长度staticinlinevoidskb_split_no_header(structsk_buff ...
* skb_push - add data to the start of a buffer * @skb : buffer to use * @len : amount of data to add * * This function extends the used data area of the buffer at the buffer * start. If this would exceed the total buffer headroom the kernel will * panic. A pointer to the ...
On input, the 'csum' field can be used to store a checksum calculated by the device. If the device indicates 'CHECKSUM_HW' in the SKB 'ip_summed' field, this means that 'csum' is the two's complement checksum of the entire packet data area starting at 'skb->data'. This is generic...
6 插入数据函数 skb_add_data() 插入数据函数和插入函数是不一样的,插入函数是把sk_buff结构体插入链表中,而插入数据函数是把数据插入sk_buff结构的数据区。函数实现如下: // skb为被添加的sk_buff类型的结构体,from为将要添加的数据源,copy为数据源的长度 static inline int skb_add_data(struct sk_buff *...
* skb_push - add data to the start of a buffer * @skb : buffer to use * @len : amount of data to add * * This function extends the used data area of the buffer at the buffer * start. If this would exceed the total buffer headroom the kernel will ...
Struct sk_buffer 是 linux TCP/IP stack 中，⽤于管理Data Buffer的结构。Sk_buffer 在数据包的发送和接收中起着重要的作⽤。为了提⾼⽹络处理的性能，应尽量避免数据包的拷贝。Linux 内核开发者们在设计 sk_buffer 结构的时候，充分考虑到这⼀点。⽬前 Linux 协议栈在接收数据的时候，需要拷贝两次：...
可以看到data_end-data一直答案都是54,也就是ip+tcp+eth的包头,但是skb->len却是总长度。 经过陈桓奇大佬的指点,我先尝试使用bpf_skb_load_bytes取数据,确实取到了,但是有一个问题,bpf_skb_load_bytes必须指定一个指针接收从skb中拷贝的数据: This helper was provided as an easy way to load data from ...
skb head/data/tail/end/介绍 This first diagram illustrates the layout of the SKB data area and where in that area the various pointers in 'structsk_buff' point. The rest of this page will walk through what the SKB data ar...查看原文...
void*data = (void*)(long)skb->data; void*data_end = (void*)(long)skb->data_end; char*payload = data +sizeof(*eth) +sizeof(*ip) +sizeof(*tcp) 这样的方法在ingress中是成功的,但是在egress宏实际获取数据是失败的,我尝试使用如下代码打印在改变payload大小: ...
void*data = (void*)(long)skb->data; void*data_end = (void*)(long)skb->data_end; char*payload = data +sizeof(*eth) +sizeof(*ip) +sizeof(*tcp) 这样的方法在ingress中是成功的,但是在egress宏实际获取数据是失败的,我尝试使用如下代码打印在改变payload大小: ...