ioctl_net.c

此源码是著名的教材BeginningLinux Programming中文名字叫Linux程序设计书中的源代码

// 示例ioctl的使用
// 本程序修改自网络上的程序，版权归原作者所有
#include <stdio.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <net/if.h>

unsigned char	g_eth_name[16];
unsigned char	g_macaddr[6];
unsigned int	g_subnetmask;
unsigned int	g_ipaddr;
unsigned int	g_broadcast_ipaddr;

/*初始化网络，获取当前网络设备的信息*/
void init_net(void)
{
	int i;
	int sock;
	struct sockaddr_in sin;
	struct ifreq ifr;

	sock = socket(AF_INET, SOCK_DGRAM, 0);
	if (sock == -1) {
		perror("socket");
	}
    
	strcpy(g_eth_name, "eth0");
    	strcpy(ifr.ifr_name, g_eth_name);
	printf("eth name:\t%s\n", g_eth_name);


	// 获取并打印网卡地址
	if (ioctl(sock, SIOCGIFHWADDR, &ifr) < 0) {
		perror("ioctl");
	}
	memcpy(g_macaddr, ifr.ifr_hwaddr.sa_data, 6);

	printf("local mac:\t");
	for(i=0;i<5;i++) {
		printf("%.2x:", g_macaddr[i]);
	}
	printf("%.2x\n",g_macaddr[i]);

	// 获取并打印IP地址
	if (ioctl(sock, SIOCGIFADDR, &ifr) < 0) {
		perror("ioctl");
	}
	memcpy(&sin, &ifr.ifr_addr, sizeof(sin));
	g_ipaddr = sin.sin_addr.s_addr;
	printf("local eth0:\t%s\n", inet_ntoa(sin.sin_addr));

	// 获取并打印广播地址
	if (ioctl(sock, SIOCGIFBRDADDR, &ifr) < 0) {
		perror("ioctl");
	}
	memcpy(&sin, &ifr.ifr_addr, sizeof(sin));
	g_broadcast_ipaddr = sin.sin_addr.s_addr;
	printf("broadcast:\t%s\n", inet_ntoa(sin.sin_addr));

	// 获取并打印子网掩码
	if (ioctl(sock, SIOCGIFNETMASK, &ifr) < 0) {
		perror("ioctl");
	}
	memcpy(&sin, &ifr.ifr_addr, sizeof(sin));
	g_subnetmask = sin.sin_addr.s_addr;
	printf("subnetmask:\t%s\n", inet_ntoa(sin.sin_addr));

	close(sock);
}

int main()
{
	/*initialize...*/
	init_net();

	/*do something*/

	return 0;
}