//
//  FFNetworkHelper.m
//  RBMS
//
//  Created by joinsik on 2015. 5. 19..
//
//

#import "FFNetworkHelper.h"
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <net/if.h>
#include <net/if_dl.h>


@implementation FFNetworkHelper

+ (NSString *)macAddress
{
    int                 mgmtInfoBase[6];
    char                *msgBuffer = NULL;
    NSString            *errorFlag = NULL;
    size_t              length;
    
    // Setup the management Information Base (mib)
    mgmtInfoBase[0] = CTL_NET;        // Request network subsystem
    mgmtInfoBase[1] = AF_ROUTE;       // Routing table info
    mgmtInfoBase[2] = 0;
    mgmtInfoBase[3] = AF_LINK;        // Request link layer information
    mgmtInfoBase[4] = NET_RT_IFLIST;  // Request all configured interfaces
    
    // With all configured interfaces requested, get handle index
    if ((mgmtInfoBase[5] = if_nametoindex("en0")) == 0)
        errorFlag = @"if_nametoindex failure";
    // Get the size of the data available (store in len)
    else if (sysctl(mgmtInfoBase, 6, NULL, &length, NULL, 0) < 0)
        errorFlag = @"sysctl mgmtInfoBase failure";
    // Alloc memory based on above call
    else if ((msgBuffer = malloc(length)) == NULL)
        errorFlag = @"buffer allocation failure";
    // Get system information, store in buffer
    else if (sysctl(mgmtInfoBase, 6, msgBuffer, &length, NULL, 0) < 0)
    {
        free(msgBuffer);
        errorFlag = @"sysctl msgBuffer failure";
    }
    else
    {
        // Map msgbuffer to interface message structure
        struct if_msghdr *interfaceMsgStruct = (struct if_msghdr *) msgBuffer;
        
        // Map to link-level socket structure
        struct sockaddr_dl *socketStruct = (struct sockaddr_dl *) (interfaceMsgStruct + 1);
        
        // Copy link layer address data in socket structure to an array
        unsigned char macAddress[6];
        memcpy(&macAddress, socketStruct->sdl_data + socketStruct->sdl_nlen, 6);
        
        // Read from char array into a string object, into traditional Mac address format
        NSString *macAddressString = [NSString stringWithFormat:@"%02X:%02X:%02X:%02X:%02X:%02X",
                                      macAddress[0], macAddress[1], macAddress[2], macAddress[3], macAddress[4], macAddress[5]];
        
        // Release the buffer memory
        free(msgBuffer);
        
        return macAddressString;
    }
    
    // Error...
    NSLog(@"Error: %@", errorFlag);
    
    return errorFlag;
}
@end
