NIC の MAC address を取得することに成功

NIC の MAC address を取得するも失敗 - Shammerismの文字化け調査で、ioctl request to get the HW addressを発見。ここの08-12-2003のコードでうまくいった。

#include <arpa/inet.h>
#include <errno.h>
#include <linux/if_ether.h>
#include <net/if.h> // ifr
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h> // ioctl
#include <sys/types.h>
#include <sys/socket.h>
#include <unistd.h> // close

// http://cboard.cprogramming.com/linux-programming/43261-ioctl-request-get-hw-address.html
void print_mac_address(const struct ifreq ifreq){
    printf("Device %s -> Ethernet %02x:%02x:%02x:%02x:%02x:%02x\n", ifreq.ifr_name,
	   (int) ((unsigned char *) &ifreq.ifr_hwaddr.sa_data)[0],
	   (int) ((unsigned char *) &ifreq.ifr_hwaddr.sa_data)[1],
	   (int) ((unsigned char *) &ifreq.ifr_hwaddr.sa_data)[2],
	   (int) ((unsigned char *) &ifreq.ifr_hwaddr.sa_data)[3],
	   (int) ((unsigned char *) &ifreq.ifr_hwaddr.sa_data)[4],
	   (int) ((unsigned char *) &ifreq.ifr_hwaddr.sa_data)[5]);
}

int main(int argc, char **args){
    int fd, status, i;
    struct ifreq ifr;
    fd = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
    if( fd < 0 ){
	perror("socket() failed.\n");
	exit(EXIT_FAILURE);
    }

    // Access to NIC and get information
    memset(&ifr, 0, sizeof(ifr));
    snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "%s", args[1]);
    status = ioctl(fd, SIOCGIFHWADDR, &ifr);
    if( status < 0 ){
	perror("ioctl() failed to get source MAC address.\n");
	exit(EXIT_FAILURE);
    }
    close(fd);
    print_mac_address(ifr);
    
    return 0;
}