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網絡卡驅動之虛擬網絡卡驅動編寫

#include <Linux/module.h>
#include <linux/errno.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/in.h>
#include <linux/skbuff.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/bitops.h>
#include <linux/delay.h>
#include <linux/gfp.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/irq.h>
#include<linux/slab.h>
#include<linux/ip.h>
static struct net_device *vnet_dev;




static void emulator_rx_packet(struct sk_buff *skb, struct net_device *dev)
{
/*參考LDD3*/
unsigned char *type;
//char *data;
//int len;
struct iphdr *ih;
//struct net_device *dest;
__be32 *saddr, *daddr, tmp;
unsigned char tmp_dev_addr[ETH_ALEN];
struct ethhdr *ethhdr;
struct sk_buff *rx_skb;

// 從硬體讀出/儲存資料
/* 對調"源/目的"的mac地址 */
ethhdr = (struct ethhdr *)skb->data;
memcpy(tmp_dev_addr, ethhdr->h_dest, ETH_ALEN);
memcpy(ethhdr->h_dest, ethhdr->h_source, ETH_ALEN);
memcpy(ethhdr->h_source, tmp_dev_addr, ETH_ALEN);
/* 對調"源/目的"的ip地址 */    
ih = (struct iphdr *)(skb->data + sizeof(struct ethhdr));


saddr = &ih->saddr;
daddr = &ih->daddr;
tmp = *saddr;
*saddr = *daddr;
*daddr = tmp;
//((u8 *)saddr)[2] ^= 1; /* change the third octet (class C) */
//((u8 *)daddr)[2] ^= 1;
type = skb->data + sizeof(struct ethhdr) + sizeof(struct iphdr);
//printk("tx package type = %02x\n", *type);
// 修改型別, 原來0x8表示ping

*type = 0; /* 0表示reply */

ih->check = 0;  /* and rebuild the checksum (ip needs it) */
ih->check = ip_fast_csum((unsigned char *)ih,ih->ihl);
// 構造一個sk_buff
rx_skb = dev_alloc_skb(skb->len + 2);
skb_reserve(rx_skb, 2); /* align IP on 16B boundary */
memcpy(skb_put(rx_skb, skb->len), skb->data, skb->len);
/* Write metadata, and then pass to the receive level */
rx_skb->dev = dev;
rx_skb->protocol = eth_type_trans(rx_skb, dev);
rx_skb->ip_summed = CHECKSUM_UNNECESSARY; /* don't check it */
dev->stats.rx_packets++;
dev->stats.rx_bytes += skb->len;


// 提交sk_buff

netif_rx(rx_skb);
}
static int gh_start_xmit(struct sk_buff *skb, struct net_device *dev)
{


static int cnt = 0;
printk("virt_net_send_packet cnt = %d\n", ++cnt);

/*停止該網絡卡的佇列*/
netif_stop_queue(dev);
/*把sk_buff的資料寫入網絡卡*/
/******************************/


/*構造一個假包,來上報*/
emulator_rx_packet(skb,dev);


/*已經把sk_buf的資料寫入網絡卡了,我們釋放*/
dev_kfree_skb(skb);
netif_wake_queue(dev);
/*更新統計資訊*/
vnet_dev->stats.tx_packets++;
vnet_dev->stats.tx_bytes +=skb->len;


return 0;
}


static const struct net_device_ops gh_netdev_ops = {
.ndo_start_xmit= gh_start_xmit,
};


static int virtnet_init(void)
{


/*1.分配一個net_device結構體**/
vnet_dev=alloc_netdev(0, "ghnet%d", ether_setup);
/*2.設定*/
vnet_dev->netdev_ops= &gh_netdev_ops;


/*設定mac地址*/
vnet_dev->dev_addr[0] = 0x08;
vnet_dev->dev_addr[1] = 0x89;
vnet_dev->dev_addr[2] = 0x89;
vnet_dev->dev_addr[3] = 0x89;
vnet_dev->dev_addr[4] = 0x89;
vnet_dev->dev_addr[5] = 0x11;


/* 設定下面兩項才能ping通 */
vnet_dev->flags           |= IFF_NOARP;
vnet_dev->features        |= NETIF_F_NO_CSUM;


/*3.註冊*/
register_netdev(vnet_dev);
return 0;
}


static void virtnet_exit(void)
{
unregister_netdev(vnet_dev);
free_netdev(vnet_dev);
}


module_init(virtnet_init);
module_exit(virtnet_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("EIGHT");