#include <sys/types.h>  
#include <sys/ioctl.h>  
#include <sys/socket.h>  
#include <net/if.h>  
#include <stdio.h>  
#include <stdlib.h>  
#include <unistd.h>  
#include <netdb.h>  
#include <string.h>  
#include <fcntl.h>  
#include <string.h>  
#include <errno.h>
typedef uint32_t uint32; 
#define MAX_IF 10
int 
main()
{
	struct ifreq ifVec[MAX_IF];//用來儲存所有介面
	
	int sock = -1;
	if ( (sock = socket( AF_INET, SOCK_DGRAM, 0 )) < 0 )
		fprintf(stderr, "Error:%d, cannot open RAM;\n");
	
	// get if vector
 	struct ifconf ioIfConf;
    	ioIfConf.ifc_buf = (void *)ifVec;
       	ioIfConf.ifc_len = sizeof(ifVec);
	 printf("Len:%d\n", ioIfConf.ifc_len);     
		
	if (ioctl(sock, SIOCGIFCONF, &ioIfConf) < 0 )//獲取所有網路介面資訊
		fprintf(stderr, "Error:%d   ioctl IFCONF\n");
	
	 printf("Len:%d\n", ioIfConf.ifc_len);// 和前面到len對比，發現ioctl修改裡len到大小     
	//迴圈列印每個網路介面到資訊
	{
		struct ifreq *ifPt;
		struct ifreq *ifEndPt;
		ifPt = ifVec;
		ifEndPt = (void *)((char *)ifVec + ioIfConf.ifc_len);
		for (ifPt = ifVec; ifPt < ifEndPt; ifPt++)
		{
			struct ifreq ifReq;
			if ( ifPt->ifr_addr.sa_family != AF_INET ) {
                		continue;
            		}
			
			// Temp keepers of interface params...
			uint32 u32_addr, u32_mask;
			
			/*	列印ip地址	*/
			char ipDotBuf[16], subnetDotBuf[16], maskDotBuf[16]; // 儲存點分十進位制到ip地址
			u32_addr = ((struct sockaddr_in *)&ifPt->ifr_addr)->sin_addr.s_addr;
			inet_ntop(AF_INET, &u32_addr, ipDotBuf, (socklen_t )sizeof(ipDotBuf)); 
			printf("IP Address: %s\n", ipDotBuf);
			
			/*    列印地址掩碼    */
			bzero(&ifReq,sizeof(struct ifreq));  
			memcpy(ifReq.ifr_name, ifPt->ifr_name, sizeof(ifReq.ifr_name));  
			if (ioctl(sock, SIOCGIFNETMASK, &ifReq ) < 0){
				fprintf(stderr, "Error: %d, cannot get mask\n", errno);
			}
			else{
				u32_mask = ((struct sockaddr_in *)&ifReq.ifr_addr)->sin_addr.s_addr;
				inet_ntop(AF_INET, &u32_mask, maskDotBuf, (socklen_t )sizeof(maskDotBuf));
				printf("Mask: %s\n", maskDotBuf);
			}	
			/*    列印MTU    */
			bzero(&ifReq,sizeof(struct ifreq));  
			memcpy(ifReq.ifr_name, ifPt->ifr_name, sizeof(ifReq.ifr_name));  
			if (ioctl(sock, SIOCGIFMTU, &ifReq ) < 0){
				fprintf(stderr, "Error: %d, cannot get MTU\n", errno);
			}
			else{
				printf("SIOCGIFMTU:%d\n", ifReq.ifr_mtu); 
			}
	           /*    其他資訊的列印方式與掩碼和MTU相同    */
		}
	}
	
	
	
}