參看 http://blog.chinaunix.net/uid-20692625-id-3172833.html

#include <stdio.h>
#include <fcntl.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <net/if.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#if 0
struct ifreq
{
	char ifr_name[IFNAMSIZ]; /* Interface name */ 
	union { 
		struct sockaddr ifr_addr; 
		struct sockaddr ifr_dstaddr; 
		struct sockaddr ifr_broadaddr; 
		struct sockaddr ifr_netmask; 
		struct sockaddr ifr_hwaddr; 
		short ifr_flags; 
		int ifr_ifindex; 
		int ifr_metric; 
		int ifr_mtu; 
		struct ifmap ifr_map; 
		char ifr_slave[IFNAMSIZ]; 
		char ifr_newname[IFNAMSIZ]; 
		char * ifr_data; 
		}; 
}
struct ifconf { 
	int ifc_len; /* size of buffer */
	union { 
		char * ifc_buf; /* buffer ddress */ 
		struct ifreq *ifc_req; /* array of structures */
	}; 
};
#endif 

int MyifconfigTest()
{
	int i = 0;
	struct ifreq * ifr = NULL;
	struct ifconf ifc;
	//初始化ifconf
	unsigned char buf[1024] = {0};
	ifc.ifc_len = 1024;
	ifc.ifc_buf = buf;

	int sock = socket(AF_INET, SOCK_DGRAM, 0);
	if (sock < 0){
	    perror("create socket failed:");
	    return -1;
	}
	
	if (ioctl(sock, SIOCGIFCONF, (char *) &ifc) < 0){
	    perror("ioctl-conf:");
		close(sock);
	    return -1;
	}	
	//printf("ifc.ifc_len %d\n",ifc.ifc_len);
	//printf("We have %d network card\n",ifc.ifc_len/sizeof(struct ifreq));
	ifr = (struct ifreq*)buf;  
	for(i = 0;i < ifc.ifc_len/sizeof(struct ifreq);i++){
	//網絡卡名
		printf("\n%s", ifr->ifr_name);
	//網絡卡flags值
		if(ioctl(sock, SIOCGIFFLAGS, ifr)>=0){
			if(IFF_UP & ifr->ifr_flags){
				printf(" [UP]\n");
			}else /*if(IFF_DOWN & ifr->ifr_flags)*/{
				printf(" [DOWN]\n");
			}
		}else{
			perror("	ioctl SIOCGIFFLAGS error");
		}
		
	//網絡卡硬體地址
		if(ioctl(sock, SIOCGIFHWADDR, ifr)>=0){
			u_int8_t hd[6] = {0};
			memcpy(hd, ifr->ifr_hwaddr.sa_data, sizeof(hd));
			printf("	HWaddr: %02X:%02X:%02X:%02X:%02X:%02X\n", hd[0], hd[1], hd[2], hd[3], hd[4], hd[5]);
		}else{
			perror("	ioctl SIOCGIFHWADDR error");
		}
		
	//網絡卡本地IP地址
		//Get
		if(ioctl(sock, SIOCGIFADDR, ifr)>=0){
			printf("	IP: %s\n",inet_ntoa(((struct sockaddr_in*)&(ifr->ifr_addr))->sin_addr));
		}else{
			perror("	ioctl SIOCGIFADDR error");
		}	
		//Set
		//if(0 == strncmp("vmnet8",ifr->ifr_name,strlen("vmnet8")))
		if(0)
		{
			printf("	!!set vmnet8 IP!!\n");
			inet_aton( "192.168.117.4",&(((struct sockaddr_in*)&(ifr->ifr_addr))->sin_addr));
			if(ioctl( sock, SIOCSIFADDR, ifr)>=0)
				printf("	ioctl SIOCSIFADDR success.\n");
			else    
				perror("	ioctl SIOCSIFADDR error");
		}
		
	//網絡卡本地廣播地址
		//Get
		if(ioctl(sock, SIOCGIFBRDADDR, ifr)>=0){
			printf("	Bcast: %s\n",inet_ntoa(((struct sockaddr_in*)&(ifr->ifr_broadaddr))->sin_addr));
		}else{
			perror("	ioctl SIOCGIFBRDADDR error");
		}
		//Set
		//if(0 == strncmp("vmnet8",ifr->ifr_name,strlen("vmnet8")))
		if(0)
		{
			printf("	!!set vmnet8 Bcast!!\n");
			inet_aton( "192.168.117.255",&(((struct sockaddr_in*)&(ifr->ifr_broadaddr))->sin_addr));
			if(ioctl( sock, SIOCSIFBRDADDR, ifr)>=0)
				printf("	ioctl SIOCSIFBRDADDR success.\n");
			else    
				perror("	ioctl SIOCSIFBRDADDR error");
		}
		
	//網絡卡子網掩碼地址
		//Get
		if(ioctl(sock, SIOCGIFNETMASK, ifr)>=0){
			printf("	Mask: %s\n",inet_ntoa(((struct sockaddr_in*)&(ifr->ifr_netmask))->sin_addr));
		}else{
			perror("	ioctl SIOCGIFNETMASK error");
		}	
		//Set
		//if(0 == strncmp("vmnet8",ifr->ifr_name,strlen("vmnet8")))
		if(0)
		{
			printf("	!!set vmnet8 Mask!!\n");
			inet_aton( "255.255.255.0",&(((struct sockaddr_in*)&(ifr->ifr_netmask))->sin_addr));
			if(ioctl( sock, SIOCSIFNETMASK, ifr)>=0)
				printf("	ioctl SIOCSIFNETMASK success.\n");
			else    
				perror("	ioctl SIOCSIFNETMASK error");
		}
		
		//網絡卡MTU值
		if(ioctl(sock, SIOCGIFMTU, ifr)>=0){
			printf("	MTU: %d\n",ifr->ifr_mtu);
		}else{
			perror("	ioctl SIOCGIFMTU error");
		}
		
		//網絡卡NREAD值
		int nread = 0;
		if(ioctl(sock, FIONREAD, &nread)>=0){
			printf("	nread: %d\n",nread);
		}else{
			perror("	ioctl FIONREAD error");
		}			
		ifr++;	  
	}
	close(sock);
}
int main(int argc,char **argv)
{	
	MyifconfigTest();	
}