筆記!

檔案內容為:

#include <stdio.h>

int main() {

原本得到的IP位址為16進制的 0a01a8c0  (192.168.1.10)

Linux Kernel 取得網路介面卡資訊:

使用slab memory 、hlist table、setup_timer、SPINLOCK筆記:

typedef struct _traffic_entry

{

        struct hlist_node hlist;

        unsigned char dev[DEV_NAME_LEN];

        unsigned int ipaddr;

        unsigned char macaddr[ETH_ALEN];

        unsigned long TX_pkts;

        unsigned long RX_pkts;

        unsigned long TX_bytes;

        unsigned long RX_bytes;

        unsigned long init_time;

        unsigned long timestamp;

        struct rcu_head rcu;

} traffic_entry;

static traffic_entry *tm_entry;  /*用於指向暫存entry的指標*/

static struct kmem_cache *tf_db_cache __read_mostly; /*宣告使用slab memory*/

static DEFINE_SPINLOCK(hlist_lock);  /*宣告用來做SPINLOCK的flag*/

static struct timer_list tfm_timer;    /*宣告用來做Timer*/

#define TF_TIMEOUT                      300000 //ms (5 minutes)

#define EXE_INTERVAL           60000  //ms (30 seconds)

static void tdb_rcu_free(struct rcu_head *head)

{

    struct _traffic_entry *ent= container_of(head, struct _traffic_entry, rcu);

kmem_cache_free(tf_db_cache, ent);

}

/*用來釋放不需使用的slab memory*/

static inline void tdb_delete(struct _traffic_entry *f)

{

    hlist_del_rcu(&f->hlist);

call_rcu(&f->rcu, tdb_rcu_free);

}

/*刪除逾期的資料，由setup_timer所trigger*/

static inline void tfm_entry_cleanup(void)

{

    int i = 0,hash_cnt = 0;

    struct hlist_node *node = NULL;

    traffic_entry *entry = NULL;

/*為了避免共同存取eth_hash這個hash table的structure，因此在存取eth_hash時，會先將之lock住*/

spin_lock_bh(&hlist_lock);

for(i = 0; i < TRAFFIC_HEAD_SIZE; i++)

{

    for(hash_cnt = 0; hash_cnt < TRAFFIC_HASH_SIZE; hash_cnt++)

        {

                hlist_for_each_entry_rcu(entry,node,&eth_hash[hash_cnt],hlist)

                {

            this_timer = entry->timestamp + TF_TIMEOUT;

                        if (time_before_eq(this_timer, jiffies))

                        {

                                tdb_delete(entry);

}

                }

     }

}

/*待eth_hash  table 存取完之後，會將之unlock*/

spin_unlock_bh(&hlist_lock);

/*由mod_timer去修改下一次要被trigger的時間，EXE_INTERVAL為時間間隔*/

mod_timer(&tfm_timer, jiffies + msecs_to_jiffies(EXE_INTERVAL));

return;

}

int traffic_monitor(struct sk_buff *mskb)

{

spin_lock_bh(&hlist_lock);

add_dentry = find_macaddr_entry(ethh->h_dest, mskb->dev->name); 

if (add_dentry==NULL) 

{

tm_entry = kmem_cache_alloc(tf_db_cache, GFP_ATOMIC);

if (tm_entry) 

{

if (add_dentry == NULL) 

{

hash_addr = mac_hash(ethh->h_dest);

memset(tm_entry->dev,0x0,DEV_NAME_LEN);

memcpy(tm_entry->dev,mskb->dev->name,DEV_NAME_LEN );

memset(tm_entry->macaddr,0x0,ETH_ALEN );

memcpy(tm_entry->macaddr,ethh->h_dest,ETH_ALEN );

tm_entry->ipaddr = iph->daddr;     

tm_entry->TX_pkts = 0;

tm_entry->TX_bytes = 0;

tm_entry->RX_pkts = 1; 

tm_entry->RX_bytes = mskb->len;

tm_entry->init_time = jiffies;

tm_entry->timestamp = jiffies;

}

hlist_add_head_rcu(&tm_entry->hlist,&eth_hash[hash_addr]);

}

}

spin_unlock_bh(&hlist_lock);

return 0;

}

/*用來trigger 檢查是否有entry已逾時，可以將之刪除*/

int initial_timer()

{

    int ret = 0;

    printk("Initial timer \n");

    setup_timer(&tfm_timer, tfm_entry_cleanup, 0);

     /*2秒後trigger一次tfm_entry_cleanup*/

    ret = mod_timer(&tfm_timer, jiffies + msecs_to_jiffies(2000));

    if(ret)  printk("can't trigger tfm_timer\n");

    return 0;

}

int clear_timer()

{

int ret = 0;

    printk("Delete Timer\n");

    ret = del_timer(&tfm_timer);

    if (ret)

    {

        printk("can't delete tfm_timer, try again after 5 ms!");

        mdelay(5);

        ret = del_timer(&tfm_timer);

        if (ret) printk("still can't delete timer!");

     }

   return 0;

}

static int tfm_func(struct sk_buff *skb)

{

    if(!skb || !skb->data) return 0;

        traffic_monitor(skb);

     return 0;

}

static int __init init(void)

{

tf_db_cache= kmem_cache_create("traffic_db_cache", sizeof(struct _traffic_entry),0,SLAB_HWCACHE_ALIGN, NULL);

    if (!tf_db_cache)

        return -ENOMEM;

        return 0;

}

static void __exit fini(void)

{

    kmem_cache_destroy(tf_db_cache);

}

參考網址1: http://bbs.chinaunix.net/thread-2093822-1-1.html  (投石问路：kmem_cache_alloc函数使用问题)

參考網址2: http://blog.csdn.net/z1179675084/article/details/8741971 (z1179675084的專欄  linux內核定時器)

參考網址3:http://nano-chicken.blogspot.tw/search?q=timer (Nano 雞排 Linux Kernel (7.1)-timer)

參考網址4: http://www.ibm.com/developerworks/cn/linux/l-timers-list/ (內核API, 第3部份: 2.6內核中的計時器和列表)

筆記一下建立/proc的方式:

#include <linux/proc_fs.h>