linux网络协议栈分析笔记7-VLAN的处理

这次先看看VLAN怎么处理的        主要代码目录linux/net/8021q

dev_add_pack(& vlan_packet_type);         vlan-802.1q

---

static struct packet_type vlan_packet_type __read_mostly = {
     .type = cpu_to_be16(ETH_P_8021Q),
      .func = vlan_skb_recv, /* VLAN receive method */
};

---

->vlan_skb_recv

     ->skb = skb_share_check(skb, GFP_ATOMIC);     检查是否有其他协议共享处理此skb

     ->vhdr = (struct  vlan_hdr *)skb->data;      指向VLAN tag字段

        vlan_tci = ntohs(vhdr->h_vlan_TCI);
        vlan_id = vlan_tci & VLAN_VID_MASK;

     struct  vlan_hdr {

     __be16     h_vlan_TCI;             下图中的Tag Control Info      
     __