Linux 获取本机IP地址和MAC地址（三）

获得网络接口为eth0的IP地址

#include
#include
#include
#include
#include
#include
#include
#include
#include

#define MAXINTERFACES 16
#define MAC_ADDR_LEN 18
#define ADDR_LEN 16

#define ETH_INTERFACE_NAME "eth0"

void err_quit(char *msg);
char *getIP(char *addr);

int main(int argc, char *argv[])
{
        char addr[ADDR_LEN];

        getIP(addr);

        return 0;
}

void err_quit(char *msg)
{
        perror(msg);
        exit(1);
}

char *getIP(char *addr)
{
        int sock_fd;
        struct ifreq ifr;

        if((sock_fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
         err_quit("Create socket failed");

        strncpy(ifr.ifr_name, ETH_INTERFACE_NAME, IF_NAMESIZE);
        ifr.ifr_name[IF_NAMESIZE - 1] = '\0';

        if(ioctl(sock_fd, SIOCGIFADDR, &ifr) < 0)
                err_quit("Get interface address failed");

        addr = inet_ntoa(((struct sockaddr_in*)(&ifr.ifr_addr))->sin_addr);
        printf("IP address is %s\n", addr);

        return addr;
}