Linux: network :创建raw socket的时候

创建socket的函数packet_create，会注册一个 packet_rcv相关的回调函数。
这个函数负责将packet，skb的对象，放到socket queue里。在BPF过滤之后。

/*
 * This function makes lazy skb cloning in hope that most of packets
 * are discarded by BPF.
 *
 * Note tricky part: we DO mangle shared skb! skb->data, skb->len
 * and skb->cb are mangled. It works because (and until) packets
 * falling here are owned by current CPU. Output packets are cloned
 * by dev_queue_xmit_nit(), input packets are processed by net_bh
 * sequencially, so that if we return skb to original state on exit,
 * we will not harm anyone.
 */

如果注册的是arp层的raw socket，最终二层ARP的处理是通过遍历ptype，会顺序调用arp_rcv/arp_process来完成neigbor的更新等操作ÿ