#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <getopt.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <net/if.h>
#include <stdlib.h>
#include <unistd.h>
#include <linux/ethtool.h>
#include <linux/sockios.h>
 
typedef unsigned short u16;
typedef unsigned int u32;
typedef unsigned char u8;
 
 /* 獲取MII phy的地址 然後讀取phy暫存器的值*/
int detect_mii(int skfd, char *ifname)
{
   struct ifreq ifr;
   u16 *data, mii_val;
   unsigned phy_id;
 
   /* Get the vitals from the interface. */
   strncpy(ifr.ifr_name, ifname, IFNAMSIZ);
 
   if (ioctl(skfd, SIOCGMIIPHY, &ifr) < 0)
      {
         fprintf(stderr, "SIOCGMIIPHY on %s failed: %s\n", ifname, strerror(errno));
         (void) close(skfd);
         return 2;
      }
 
   data = (u16 *)(&ifr.ifr_data);
   phy_id = data[0];
   data[1] = 1;
 
   if (ioctl(skfd, SIOCGMIIREG, &ifr) < 0)
     {
        fprintf(stderr, "SIOCGMIIREG on %s failed: %s\n", ifr.ifr_name, strerror(errno));
        return 2;
     }
 
   mii_val = data[3];
   return(((mii_val & 0x0016) == 0x0004) ? 0 : 1);
}
 
int detect_ethtool(int skfd, char *ifname)
{
   struct ifreq ifr; /* ifreq裡包含了介面的所有資訊，比如介面名，地址等等 */
   struct ethtool_value edata;
   
   memset(&ifr, 0, sizeof(ifr));
   edata.cmd = ETHTOOL_GLINK;
   
   /* 設定要查詢的網絡卡介面名稱 */
   strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name)-1);
   ifr.ifr_data = (char *) &edata;
 
   if (ioctl(skfd, SIOCETHTOOL, &ifr) == -1)
     {
        printf("ETHTOOL_GLINK failed: %s\n", strerror(errno));
        return 2;
     }
 
   return (edata.data ? 0 : 1);
}
 
int CheckNet()
{
	int skfd = -1;
	/* 如果這裡所填的名字沒有對應的phy（比如phy2），則會報錯No such device */
	char *ifname = "eth0";
	int retval;
 
	/* Open a socket. */
	if (( skfd = socket( AF_INET, SOCK_DGRAM, 0 ) ) < 0 )
	{
		printf("socket error\n");
		exit(-1);
	}
 
	/* 這裡使用兩種方式來獲取網絡卡的狀態 */
	retval = detect_ethtool(skfd, ifname); /* 使用SIOCETHTOOL方式獲取 */
	if (retval == 2)
	{
		retval = detect_mii(skfd, ifname); /*使用SIOCGMIIPHY方式獲取，即先獲取指定phy的地址，然後讀指定的暫存器*/
	}
	
	close(skfd);
 
	return retval;
}
 
//int main(int argc, char **argv)
int phyOperate(void* arg)
{
	int ret = -1,retold = -1;
	while(1)
	{
		ret = CheckNet();
		/*如果狀態發生變化才打印*/
		if(ret != retold)
		{
			retold = ret;
			if (ret == 2)
				printf("Could not determine status\n");
			if (ret == 1)
				printf("Link down %s pid = %d\n",(char*)arg,getpid());
			if (ret == 0)
				printf("Link up %s pid = %d\n",(char*)arg,getpid());
		}
	}
}

/*多個執行緒檢測網絡卡狀態*/
int main()
{
	int i = 0;
	pthread_t thread1,thread2,thread3,thread4;
	
	pthread_create(&thread1,NULL,phyOperate,"thread1");
	pthread_create(&thread2,NULL,phyOperate,"thread2");
	pthread_create(&thread3,NULL,phyOperate,"thread3");
	//pthread_create(&thread4,NULL,phyOperate,"thread4");
	
	/*不加下面的話執行緒會結束*/
	pthread_join(thread1,"thread1");
	pthread_join(thread2,"thread2");
	pthread_join(thread3,"thread3");
	//pthread_join(thread4,"thread4");

}