LinuxですべてのNIC情報を取得

#include 
#include 
#include 
#include 
#include 

int main()
{
    struct ifreq ifr;
    struct ifconf ifc;
    char buf[2048];
    int success = 0;

    int sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
    if (sock == -1) {
        printf("socket error
");
        return -1;
    }

    ifc.ifc_len = sizeof(buf);
    ifc.ifc_buf = buf;
    if (ioctl(sock, SIOCGIFCONF, &ifc) == -1) {
        printf("ioctl error
");
        return -1;
    }

    struct ifreq* it = ifc.ifc_req;
    const struct ifreq* const end = it + (ifc.ifc_len / sizeof(struct ifreq));
    char szMac[64];
    int count = 0;
    for (; it != end; ++it) {
        strcpy(ifr.ifr_name, it->ifr_name);
        if (ioctl(sock, SIOCGIFFLAGS, &ifr) == 0) {
            if (! (ifr.ifr_flags & IFF_LOOPBACK)) { // don't count loopback
                if (ioctl(sock, SIOCGIFHWADDR, &ifr) == 0) {
                    count ++ ;
                    unsigned char * ptr ;
                    ptr = (unsigned char  *)&ifr.ifr_ifru.ifru_hwaddr.sa_data[0];
                    snprintf(szMac,64,"%02X:%02X:%02X:%02X:%02X:%02X",*ptr,*(ptr+1),*(ptr+2),*(ptr+3),*(ptr+4),*(ptr+5));
                    printf("%d,Interface name : %s , Mac address : %s 
",count,ifr.ifr_name,szMac);
                }
            }
        }else{
            printf("get mac info error
");
            return -1;
        }
    }
}

1,Interface name : eth0 , Mac address : 90:B1:1D:87:13:75 
2,Interface name : virtac , Mac address : 52:54:00:96:E0:BF 
3,Interface name : map , Mac address : 52:54:00:F2:FE:9C 
4,Interface name : poi , Mac address : 52:54:00:1B:97:82 
5,Interface name : vnet1 , Mac address : 52:54:00:05:14:E3