呼叫: [類名 getMacAddress]
e.g. mac = @”02:48:00:00:00:00”

+ (NSString *)getMacAddress

{

    int mib[6];

    size_t len;

    char *buf;

    unsigned char *ptr;

    struct if_msghdr *ifm;

    struct sockaddr_dl *sdl;

    mib[0] = CTL_NET;

    mib[1] = AF_ROUTE;

    mib[2] = 0;

    mib[3] = AF_LINK;

    mib[4
 
] = NET_RT_IFLIST;



    if ((mib[5] = if_nametoindex("en0")) == 0) {

        printf("Error: if_nametoindex error/n");

        return NULL;

    }

    if (sysctl(mib, 6, NULL, &len, NULL, 0) < 0) {

        printf("Error: sysctl, take 1/n");

        return NULL;

    }

    if ((buf = malloc(len)) == NULL
 
) {

        printf("Could not allocate memory. error!/n");

        return NULL;

    }

    if (sysctl(mib, 6, buf, &len, NULL, 0) < 0) {

        printf("Error: sysctl, take 2");

        return NULL;

    }



    ifm = (struct if_msghdr *)buf;

    sdl = (struct sockaddr_dl *)(ifm + 1);

    ptr = (unsigned
 
 char *)LLADDR(sdl);

    NSString *outstring = [NSString stringWithFormat:@"%02x:%02x:%02x:%02x:%02x:%02x", *ptr, *(ptr+1), *(ptr+2), *(ptr+3), *(ptr+4), *(ptr+5)];

    free(buf);

    return [outstring uppercaseString];

}