网络过滤器钩子注册与网络子系统-Netfilterhookregistrationwithnetworkingsubsystem

While exploring netfilter functionality I tried to write a simple netfilter module and registered a hook as follows:

在探索netfilter功能的同时，我尝试编写一个简单的netfilter模块，并注册了一个钩子如下:

    dhcp_nfho.owner             = THIS_MODULE;
    dhcp_nfho.hook              = dhcp_hook_function;
    dhcp_nfho.hooknum           = NF_INET_POST_ROUTING;
    dhcp_nfho.priority          = NF_IP_PRI_FIRST;
    dhcp_nfho.pf            = PF_INET; // not on bridge interface
    nf_register_hook(&dhcp_nfho);

I looked into the code of nf_register_hook in the LXR page: (3.13 version)

我在LXR页面中查看了nf_register_hook的代码:(3.13版本)

int nf_register_hook(struct nf_hook_ops *reg)
 69 {
 70         struct nf_hook_ops *elem;
 71         int err;
 72 
 73         err = mutex_lock_interruptible(&nf_hook_mutex);
 74         if (err <0)
 75                 return err;
 76         list_for_each_entry(elem, &nf_hooks[reg->pf][reg->hooknum], list) {
 77                 if (reg->priority priority)
 78                         break;
 79         }
 80         list_add_rcu(®->list, elem->list.prev);
 81         mutex_unlock(&nf_hook_mutex);
 82 #if defined(CONFIG_JUMP_LABEL)
 83         static_key_slow_inc(&nf_hooks_needed[reg->pf][reg->hooknum]);
 84 #endif
 85         return 0;
 86 }

What is this 2D linked list nf_hooks[PF][hooknum]. It looks like for each protocol family there is a list of PRE/INPUT/FORWARD/OUTPUT/POST hooks?

这个二维链表nf_hooks[PF][hooknum]是什么?似乎每个协议族都有一个预/输入/前向/输出/后向钩子的列表?

How is this 2D array used by the netfilter sub system ?

netfilter子系统如何使用这个2D数组?

And is the netfilter subsystem code interacting with the network driver code? (since the hooks are processed in Soft-irq and the network driver also uses soft-irq's to process the packets)?

netfilter子系统代码与网络驱动程序代码交互吗?(因为钩子是在软irq中处理的，网络驱动也使用软irq来处理数据包)?

Where can I find the code that invokes the Netfilter Hooks once a packet is recvd by the driver?

一旦数据包被驱动程序接收，我在哪里可以找到调用Netfilter钩子的代码?

1 个解决方案