ioctl获取本地IP和MAC地址

参考了一些网上的方法，整理如下：

#include <net/if.h>
#include <sys/ioctl.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#define ETH_NAME	"eth0"

int main()
{
	int					sockfd;
	struct sockaddr_in	sin;
	struct ifreq		ifr;
	unsigned char		mac[6];
	
	sockfd = socket(AF_INET, SOCK_DGRAM, 0);
	if (sockfd == -1) {
		perror("socket error");
		exit(1);
	}
	
	strncpy(ifr.ifr_name, ETH_NAME, IFNAMSIZ);		//Interface name
	
	if (ioctl(sockfd, SIOCGIFADDR, &ifr) == 0) {	//SIOCGIFADDR 获取interface address
		memcpy(&sin, &ifr.ifr_addr, sizeof(ifr.ifr_addr));
		printf("ip:  %s\n", inet_ntoa(sin.sin_addr));
	}
	
	if (ioctl(sockfd, SIOCGIFHWADDR, &ifr) == 0) {	//SIOCGIFHWADDR 获取hardware address
		memcpy(mac, ifr.ifr_hwaddr.sa_data, 6);
		printf("mac: %02x:%02x:%02x:%02x:%02x:%02x\n", mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
	}
	
	return 0;
}

/*
struct ifreq {
	char ifr_name[IFNAMSIZ];
	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;
	};
};
*/