297 lines
5.9 KiB
C
297 lines
5.9 KiB
C
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/timer.h>
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#include <linux/uaccess.h>
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#include <linux/sysctl.h>
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#include <linux/ip.h>
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#include <linux/ipv6.h>
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/*
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* 三元组超时时间设置为120s
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*/
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int dpi_cache_node_timeout = 120;
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/*
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* 三元组数据结构
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*/
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struct dpi_cache_node {
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struct list_head list;
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union {
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struct in6_addr ip6;
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struct in_addr ip4;
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}ip;
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__u16 proto;
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__u16 port;
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__u32 appid;
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uint64_t uptime;
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};
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/*
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* 初始化cache链表
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*/
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#define TRIPLE_CAHCE_HASH_SIZE (2048)
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struct list_head dpi_cache_head[TRIPLE_CAHCE_HASH_SIZE] = {0};
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typedef struct pkt_info{
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unsigned int srcip;
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unsigned short sport;
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unsigned int dstip;
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unsigned short dport;
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unsigned short proto;
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}pkt_info_t;
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#define POLY 0x01101 // CRC20生成多项式x^20+x^12+x^8+1即:01101 CRC32:04C11DB7L
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static unsigned int crc_table[256] = {0};
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unsigned int get_sum_poly(unsigned char data)
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{
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unsigned int sum_poly = data;
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int j;
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sum_poly <<= 24;
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for(j = 0; j < 8; j++)
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{
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int hi = sum_poly&0x80000000; // 取得reg的最高位
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sum_poly <<= 1;
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if(hi) sum_poly = sum_poly^POLY;
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}
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return sum_poly;
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}
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void create_crc_table(void) //在使用CRC20_key函数应该先建立crc表
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{
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int i;
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for(i = 0; i < 256; i++)
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{
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crc_table[i] = get_sum_poly(i&0xFF);
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}
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}
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unsigned int CRC20_key(unsigned char* data, int len)
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{
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int i;
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unsigned int reg = 0xFFFFFFFF;// 0xFFFFFFFF，见后面解释
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for(i = 0; i < len; i++)
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{
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reg = (reg<<8) ^ crc_table[((reg>>24)&0xFF) ^ data[i]];
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}
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return (reg&0XFFFFF);//得到的reg取后20作为key值
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}
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/*
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* 初始化dpi三元组hash链表
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*/
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void dpi_cache_list_init(void)
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{
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int i = 0;
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for (i = 0; i < TRIPLE_CAHCE_HASH_SIZE; i++){
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INIT_LIST_HEAD(&dpi_cache_head[i]);
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}
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return;
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}
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/*
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* 三元组hash值计算
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*/
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int dpi_cache_node_hash(struct dpi_cache_node node)
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{
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int i = 0;
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int dip = 0;
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pkt_info_t info;
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info.dport = node.port;
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info.sport = 0;
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info.srcip = 0;
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info.proto = node.proto;
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if (node.ip.ip4.s_addr !=0 ) {
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info.dstip = node.ip.ip4.s_addr;
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} else {
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for (i = 0; i < 4; ++i) {
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dip ^= node.ip.ip6.s6_addr32[i];
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}
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info.dstip = dip;
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}
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return CRC20_key((unsigned char *)&info, sizeof(pkt_info_t))&(TRIPLE_CAHCE_HASH_SIZE - 1);
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}
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/*
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* src 和dst比较，并更新dst的appid,update_appid=true,update
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*/
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bool dpi_cache_node_compare(struct dpi_cache_node src,struct dpi_cache_node dst,bool update_appid)
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{
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int i = 0;
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if (src.port != dst.port){
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return false;
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}
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if (src.proto != dst.proto){
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return false;
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}
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if(src.ip.ip4.s_addr != 0){
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if(src.ip.ip4.s_addr != dst.ip.ip4.s_addr){
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return false;
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}
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}else{
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for (i = 0; i < 4; i++){
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if (src.ip.ip6.s6_addr32[i] != dst.ip.ip6.s6_addr32[i]){
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return false;
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}
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}
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}
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if (update_appid){
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dst.appid = src.appid;
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dst.uptime = get_jiffies_64();
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}
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return true;
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}
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/*
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*遍历hash链表，查找node
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*/
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bool dpi_cache_node_search(struct dpi_cache_node node,int flag)
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{
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struct list_head * pList;
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struct dpi_cache_node *pNode;
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int hash = dpi_cache_node_hash(node);
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list_for_each(pList,&dpi_cache_head[hash]){
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pNode = list_entry(pList,struct dpi_cache_node,list);
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if (dpi_cache_node_compare(node,*pNode,flag)){
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return true;
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}
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}
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return false;
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}
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/*
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* DPI 信息记录，外部接口调用
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*/
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bool dpi_cache_node_add(struct dpi_cache_node node)
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{
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int hash = 0;
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struct dpi_cache_node *pNode =NULL;
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if (dpi_cache_node_search(node,true)) {
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return true;
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}
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pNode = kmalloc(sizeof(struct dpi_cache_node), GFP_KERNEL);
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if (NULL == pNode) {
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return false;
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}
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hash = dpi_cache_node_hash(node);
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pNode->uptime = get_jiffies_64();
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pNode->appid = node.appid;
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list_add_tail(&pNode->list,&dpi_cache_head[hash]);
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return true;
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}
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/*
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* 释放hash链表上所有node节点
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*/
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void dpi_cache_list_release(void)
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{
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struct list_head * pList = NULL;
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struct dpi_cache_node *pNode = NULL;
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int i = 0;
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for (i = 0; i < TRIPLE_CAHCE_HASH_SIZE; i++){
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list_for_each(pList,&dpi_cache_head[i]){
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pNode = list_entry(pList,struct dpi_cache_node,list);
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if(pNode){
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list_del(&pNode->list);
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}
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}
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}
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}
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/*
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*定时器超时，删除超时的节点
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*/
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void dpi_cache_node_timeout_func(void)
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{
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struct list_head * pList = NULL;
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struct dpi_cache_node *pNode = NULL;
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int i = 0;
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for (i = 0; i < TRIPLE_CAHCE_HASH_SIZE; i++){
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list_for_each(pList,&dpi_cache_head[i]){
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pNode = list_entry(pList,struct dpi_cache_node,list);
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if(pNode&&
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(get_jiffies_64() - pNode->uptime >= dpi_cache_node_timeout)){
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list_del(&pNode->list);
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}
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}
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}
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}
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/*
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* 定时器操作
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*/
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struct timer_list gTimer;
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void dpi_cache_timer_handler(unsigned long data) {
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printk(KERN_INFO"timer pending:%d\n", timer_pending(&gTimer));
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dpi_cache_node_timeout_func();
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mod_timer(&gTimer, jiffies+msecs_to_jiffies(dpi_cache_node_timeout*1000));
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}
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int dpi_cache_timer_init(void) {
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printk(KERN_INFO"%s jiffies:%ld\n", __func__, jiffies);
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printk(KERN_INFO"ji:%d,HZ:%d\n", jiffies_to_msecs(250), HZ);
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init_timer(&gTimer);
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gTimer.expires = jiffies + dpi_cache_node_timeout*HZ;
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gTimer.function = dpi_cache_timer_handler;
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add_timer(&gTimer);
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printk(KERN_INFO"timer pending:%d\n", timer_pending(&gTimer));
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return 0;
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}
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void dpi_cache_timer_exit(void) {
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printk(KERN_INFO"%s jiffies:%ld\n", __func__, jiffies);
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del_timer(&gTimer);
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}
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int dpi_cahce_module_init(void)
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{
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dpi_cache_timer_init();
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dpi_cache_list_init();
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return 1;
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}
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int dpi_cache_module_exit(void)
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{
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dpi_cache_timer_exit();
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dpi_cache_list_release();
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return 1;
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}
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module_init(dpi_cahce_module_init);
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module_exit(dpi_cache_timer_exit);
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MODULE_LICENSE("GPL");
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