iOS 获取Mac Address

#import <net/if.h>
#import <sys/sysctl.h>
#import <net/if_dl.h>

- (NSString *)macAddress
{
int  temp[6]={0};
size_t len=0;
char *buf=NULL;
unsigned char *laddr=NULL;
struct if_msghdr *ifmsghdr=NULL;
struct sockaddr_dl *sockaddr=NULL;

temp[0] = CTL_NET;
temp[1] = AF_ROUTE;
temp[2] = 0;
temp[3] = AF_LINK;
temp[4] = NET_RT_IFLIST;

temp[5] = if_nametoindex("en0");
if (0 == temp[5])
{
return nil;
}

if (sysctl(temp, 6, NULL, &len, NULL, 0) < 0)
{
return nil;
}

buf = malloc(len+32);
if (buf == NULL)
{
return nil;
}

if (sysctl(temp, 6, buf, &len, NULL, 0) < 0)
{
free(buf);

return nil;
}

ifmsghdr = (struct if_msghdr *)buf;
sockaddr = (struct sockaddr_dl *)(ifmsghdr + 1);
laddr = (unsigned char *)LLADDR(sockaddr);

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

return [outstring uppercaseString];
}