通知链netdev_chain和inetaddr_chain区别以及使用

1046 static int fib_netdev_event(struct notifier_block *this, unsigned long event, void *ptr)
1047 {
1048     struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1049     struct netdev_notifier_info_ext *info_ext = ptr;
1050     struct in_device *in_dev;
1051     struct net *net = dev_net(dev);
1052 
1053     if (event == NETDEV_UNREGISTER) {
1054         fib_disable_ip(dev, 2);
1055         rt_flush_dev(dev);
1056         return NOTIFY_DONE;
1057     }
1058 
1059     in_dev = __in_dev_get_rtnl(dev);
1060     if (!in_dev)
1061         return NOTIFY_DONE;
1062 
1063     switch (event) {
1064     case NETDEV_UP://激活一个网络设备
1065         for_ifa(in_dev) {
1066             fib_add_ifaddr(ifa);
1067         } endfor_ifa(in_dev);
1068 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1069         fib_sync_up(dev);
1070 #endif
1071         atomic_inc(&net->ipv4.dev_addr_genid);
1072         rt_cache_flush(net);
1073         break;
1074     case NETDEV_DOWN://停止一个网络设备，所有对该设备的引用都应释放
1075         fib_disable_ip(dev, 0);
1076         break;
1077     case NETDEV_CHANGEMTU:
1078         fib_sync_mtu(dev, info_ext->ext.mtu);
1079         rt_cache_flush(net);
1080         break;
1081     case NETDEV_CHANGE:
1082         rt_cache_flush(net);
1083         break;
1084     }
1085     return NOTIFY_DONE;
1086 }

 1 #include <linux/module.h>
 2 #include <linux/init.h>
 3 #include <linux/kernel.h>
 4 #include <linux/types.h>
 5 #include <linux/netdevice.h>
 6 #include <linux/inetdevice.h>
 7  
 8 //处理网络设备的启动与禁用等事件
 9 int test_netdev_event(struct notifier_block *this, unsigned long event, void *ptr)
10 {
11    struct net_device *dev = (struct net_device *)ptr;
12     switch(event)
13     {
14         case NETDEV_UP:
15              if(dev && dev->name)
16                  printk("test dev[%s] is up\n",dev->name);
17              break;
18         case NETDEV_DOWN:
19              if(dev && dev->name)
20                  printk("test  dev[%s] is down\n",dev->name);
21                 break;
22         default:
23              break;
24     }
25  
26     return NOTIFY_DONE;
27 }          
28  
29 //处理ip地址的改变事件
30 int test_inetaddr_event(struct notifier_block *this, unsigned long event, void *ptr)
31 {
32  
33     struct in_ifaddr *ifa = (struct in_ifaddr *)ptr;
34     struct net_device *dev = NULL;
35  
36     if(ifa && ifa->ifa_dev)
37         dev = ifa->ifa_dev->dev;
38  
39     switch(event)
40     {
41         case NETDEV_UP:
42             if(dev && dev->name)
43                  printk("inet[%p] is up\n",dev->name);
44             break;
45         case NETDEV_DOWN:
46              if(dev && dev->name)
47                  printk("inet[%p] is down\n",dev->name);
48         default:
49             break;
50  
51     }
52  
53     return NOTIFY_OK;
54 }
55  
56 struct notifier_block inethandle={
57     .notifier_call = test_inetaddr_event
58 };          
59                        
60 struct notifier_block devhandle={
61     .notifier_call = test_netdev_event
62 };
63  
64 static int __init  net_event_init(void)
65 {   
66     /*
67        在netdev_chain通知链上注册消息块 
68        netdev_chain通知链是内核中用于传递有关网络设备注册状态的通知信息
69     */
70     register_netdevice_notifier(&devhandle);
71     
72     /*
73       在inetaddr_chain通知链上注册消息块
74       inetaddr_chain通知链是内核中用于传递有关本地接口上的ipv4地址的插入，删除以及变更的通知信息
75     */
76     register_inetaddr_notifier(&inethandle);
77     return 0; 
78 }   
79  
80 static void __exit net_event_exit(void)
81 {
82     unregister_netdevice_notifier(&devhandle);
83     unregister_inetaddr_notifier(&inethandle);
84     return;
85 }
86  
87  
88 module_init(net_event_init);
89 module_exit(net_event_exit);
90 MODULE_LICENSE("GPL");