#include <linux/module.h>       /* Specifically, a module */

#include <linux/kernel.h>       /* We're doing kernel work */ #include <linux/proc_fs.h> #include <linux/netfilter.h> #include <linux/netfilter_ipv4.h> #include <linux/types.h> #include <linux/if_ether.h> #include<linux/tcp.h> #include<linux/ip.h> #include <linux/skbuff.h> #define IP 0x800 #define TCP 0x6 /* Necessary because we use the proc fs */ #define procfs_name "port" char *buf; struct nf_hook_ops nfho; struct proc_dir_entry *Our_Proc_File; int len=0;

unsigned int

hook_func (unsigned int hooknum,            struct sk_buff **skb,            const struct net_device *in,  const struct net_device *out, int (*okfn) (struct sk_buff *)) {   struct ethhdr *eth;   struct iphdr *iph;   struct tcphdr *tcp;   struct sk_buff *SKB;

  int ips[4],ipd[4];   SKB = *skb;   len = 0;

 

  eth = (struct ethhdr *) SKB->mac_header;

  iph = (struct iphdr *) SKB->network_header;   tcp = (struct tcphdr *) SKB->transport_header;   if (ntohs (eth->h_proto) == IP)     {       if (iph->protocol == TCP)         {

 

         len += sprintf(buf + len, "smac = %02x:%02x:%02x:%02x:%02x:%02x\n", eth->h_source[0],eth->h_source[1],eth->h_source[2],eth->h_source[3],eth->h_source[4],eth->h_source[5]);

         len += sprintf(buf + len, "dmac = %02x:%02x:%02x:%02x:%02x:%02x\n", eth->h_dest[0],eth->h_dest[1],eth->h_dest[2],eth->h_dest[3],eth->h_dest[4],eth->h_dest[5]);

        len += sprintf(buf + len, "dip = %u.%u.%u.%u\n", NIPQUAD(iph->daddr));         len += sprintf(buf + len, "sip = %u.%u.%u.%u\n", NIPQUAD(iph->daddr));          len += sprintf(buf + len, "sport = %d \n",ntohs(tcp -> source));          len += sprintf(buf + len, "dport = %d \n",ntohs(tcp -> dest));               }     }   return NF_ACCEPT;

}

 

int

procfile_read (char *buffer,                char **buffer_location,                off_t offset, int buffer_length, int *eof, void *data) {

       memcpy(buffer,buf,len);

  return len;

}   int init_module () {   buf = kmalloc(1024,GFP_KERNEL);   nfho.hook = hook_func;        /* 处理函数 */   nfho.hooknum = NF_IP_PRE_ROUTING;     /* 使用IPv4的第一个hook */   nfho.pf = PF_INET;   nfho.priority = NF_IP_PRI_FIRST;      /* 让我们的函数首先执行 */

  nf_register_hook (&nfho);

  Our_Proc_File = create_proc_entry (procfs_name, 0644, NULL);   Our_Proc_File->read_proc = procfile_read;   Our_Proc_File->owner = THIS_MODULE;   Our_Proc_File->mode = S_IFREG | S_IRUGO;   Our_Proc_File->uid = 0;   Our_Proc_File->gid = 0;   Our_Proc_File->size = 37;   return 0;                     /* everything is ok */ }

                                  

void cleanup_module () {   kfree(buf);   nf_unregister_hook (&nfho);   remove_proc_entry (procfs_name, &proc_root); }

 

makefile代码：

ifeq ($(KERNELRELEASE),)

    KERNELDIR ?= /lib/modules/$(shell uname -r)/build

     PWD := $(shell pwd)

modules:

        $(MAKE) -C $(KERNELDIR) M=$(PWD) modules

modules_install:

        $(MAKE) -C $(KERNELDIR) M=$(PWD) modules_install

clean:

        rm -rf *.o *~ core .depend .*.cmd *.ko *.mod.c .tmp_versions

.PHONY: modules modules_install clean

else

    # called from kernel build system: just declare what our modules are     obj-m := proc.o endif