Cross-Platform Way of Obtaining MAC Address of Your Machine

In one of my current projects I had to implement client-server communication and protection by MAC address when client machine can’t connect to server if its MAC address is not allowed, regardless of network or broadband connection. But what was a surprise that wxWidgets does not have API which allows obtaining MAC address in cross-platform way. So, I decided to write a small class which allows obtainig MAC address for Windows, Linux, Mac OS and Windows Mobile. Here it is:

MACAddressUtility.h

#ifndef _MACADDRESS_UTILITY_H
#define _MACADDRESS_UTILITY_H

class MACAddressUtility
{
public:
	static long GetMACAddress(unsigned char * result);
private:
#if defined(WIN32) || defined(UNDER_CE)
	static long GetMACAddressMSW(unsigned char * result);
#elif defined(__APPLE__)
	static long GetMACAddressMAC(unsigned char * result);
#elif defined(LINUX) || defined(linux)
	static long GetMACAddressLinux(unsigned char * result);
#endif
};

#endif

MACAddressUtility.cpp

#include "MACAddressUtility.h"

#include <stdio.h>

#if defined(WIN32) || defined(UNDER_CE)
#	include <windows.h>
#	if defined(UNDER_CE)
#		include <Iphlpapi.h>
#	endif
#elif defined(__APPLE__)
#	include <CoreFoundation/CoreFoundation.h>
#	include <IOKit/IOKitLib.h>
#	include <IOKit/network/IOEthernetInterface.h>
#	include <IOKit/network/IONetworkInterface.h>
#	include <IOKit/network/IOEthernetController.h>
#elif defined(LINUX) || defined(linux)
#	include <string.h>
#	include <net/if.h>
#	include <sys/ioctl.h>
#   include <sys/socket.h>
#   include <arpa/inet.h>
#endif

long MACAddressUtility::GetMACAddress(unsigned char * result)
{
	// Fill result with zeroes
	memset(result, 0, 6);
	// Call appropriate function for each platform
#if defined(WIN32) || defined(UNDER_CE)
	return GetMACAddressMSW(result);
#elif defined(__APPLE__)
	return GetMACAddressMAC(result);
#elif defined(LINUX) || defined(linux)
	return GetMACAddressLinux(result);
#endif
	// If platform is not supported then return error code
	return -1;
}

#if defined(WIN32) || defined(UNDER_CE)

inline long MACAddressUtility::GetMACAddressMSW(unsigned char * result)
{

#if defined(UNDER_CE)
	IP_ADAPTER_INFO AdapterInfo[16]; // Allocate information
	DWORD dwBufLen = sizeof(AdapterInfo); // Save memory size of buffer
	if(GetAdaptersInfo(AdapterInfo, &dwBufLen) == ERROR_SUCCESS)
	{
		memcpy(result, AdapterInfo->Address, 6);
	}
	else return -1;
#else
	UUID uuid;
	if(UuidCreateSequential(&uuid) == RPC_S_UUID_NO_ADDRESS) return -1;
	memcpy(result, (char*)(uuid.Data4+2), 6);
#endif
	return 0;
}

#elif defined(__APPLE__)

static kern_return_t FindEthernetInterfaces(io_iterator_t *matchingServices)
{
    kern_return_t		kernResult;
    CFMutableDictionaryRef	matchingDict;
    CFMutableDictionaryRef	propertyMatchDict;

    matchingDict = IOServiceMatching(kIOEthernetInterfaceClass);

    if (NULL != matchingDict)
	{
        propertyMatchDict =
			CFDictionaryCreateMutable(kCFAllocatorDefault, 0,
				&kCFTypeDictionaryKeyCallBacks,
				&kCFTypeDictionaryValueCallBacks);

        if (NULL != propertyMatchDict)
		{
            CFDictionarySetValue(propertyMatchDict,
				CFSTR(kIOPrimaryInterface), kCFBooleanTrue);
            CFDictionarySetValue(matchingDict,
				CFSTR(kIOPropertyMatchKey), propertyMatchDict);
            CFRelease(propertyMatchDict);
        }
    }
    kernResult = IOServiceGetMatchingServices(kIOMasterPortDefault,
		matchingDict, matchingServices);
    return kernResult;
}

static kern_return_t GetMACAddress(io_iterator_t intfIterator,
								   UInt8 *MACAddress, UInt8 bufferSize)
{
    io_object_t		intfService;
    io_object_t		controllerService;
    kern_return_t	kernResult = KERN_FAILURE;

	if (bufferSize < kIOEthernetAddressSize) {
		return kernResult;
	}

    bzero(MACAddress, bufferSize);

    while (intfService = IOIteratorNext(intfIterator))
    {
        CFTypeRef	MACAddressAsCFData;

        // IONetworkControllers can't be found directly by the IOServiceGetMatchingServices call,
        // since they are hardware nubs and do not participate in driver matching. In other words,
        // registerService() is never called on them. So we've found the IONetworkInterface and will
        // get its parent controller by asking for it specifically.

        // IORegistryEntryGetParentEntry retains the returned object,
		// so release it when we're done with it.
        kernResult =
			IORegistryEntryGetParentEntry(intfService,
				kIOServicePlane,
				&controllerService);

        if (KERN_SUCCESS != kernResult) {
            printf("IORegistryEntryGetParentEntry returned 0x%08x\n", kernResult);
        }
        else {
            // Retrieve the MAC address property from the I/O Registry in the form of a CFData
            MACAddressAsCFData =
				IORegistryEntryCreateCFProperty(controllerService,
					CFSTR(kIOMACAddress),
					kCFAllocatorDefault,
					0);
            if (MACAddressAsCFData) {
                CFShow(MACAddressAsCFData); // for display purposes only; output goes to stderr

                // Get the raw bytes of the MAC address from the CFData
                CFDataGetBytes((CFDataRef)MACAddressAsCFData,
					CFRangeMake(0, kIOEthernetAddressSize), MACAddress);
                CFRelease(MACAddressAsCFData);
            }

            // Done with the parent Ethernet controller object so we release it.
            (void) IOObjectRelease(controllerService);
        }

        // Done with the Ethernet interface object so we release it.
        (void) IOObjectRelease(intfService);
    }

    return kernResult;
}

long MACAddressUtility::GetMACAddressMAC(unsigned char * result)
{
	io_iterator_t	intfIterator;
	kern_return_t	kernResult = KERN_FAILURE;
	do
	{
		kernResult = ::FindEthernetInterfaces(&intfIterator);
		if (KERN_SUCCESS != kernResult) break;
	    kernResult = ::GetMACAddress(intfIterator, (UInt8*)result, 6);
    }
	while(false);
    (void) IOObjectRelease(intfIterator);
}

#elif defined(LINUX) || defined(linux)

long MACAddressUtility::GetMACAddressLinux(unsigned char * result)
{
	struct ifreq ifr;
    struct ifreq *IFR;
    struct ifconf ifc;
    char buf[1024];
    int s, i;
    int ok = 0;

    s = socket(AF_INET, SOCK_DGRAM, 0);
    if (s == -1)
	{
        return -1;
    }

    ifc.ifc_len = sizeof(buf);
    ifc.ifc_buf = buf;
    ioctl(s, SIOCGIFCONF, &ifc);

    IFR = ifc.ifc_req;
    for (i = ifc.ifc_len / sizeof(struct ifreq); --i >= 0; IFR++)
	{
        strcpy(ifr.ifr_name, IFR->ifr_name);
        if (ioctl(s, SIOCGIFFLAGS, &ifr) == 0)
		{
            if (! (ifr.ifr_flags & IFF_LOOPBACK))
			{
                if (ioctl(s, SIOCGIFHWADDR, &ifr) == 0)
				{
                    ok = 1;
                    break;
                }
            }
        }
    }

    shutdown(s, SHUT_RDWR);
    if (ok)
	{
        bcopy( ifr.ifr_hwaddr.sa_data, result, 6);
    }
    else
	{
        return -1;
    }
    return 0;
}

#endif

wxMACAddressUtility.h

#ifndef _WX_MACADDRESS_UTILITY_H
#define _WX_MACADDRESS_UTILITY_H

#include "MACAddressUtility.h"
#include <wx/wx.h>

class wxMACAddressUtility
{
public:
	static wxString GetMACAddress()
	{
		unsigned char result[6];
		if(MACAddressUtility::GetMACAddress(result) == 0)
		{
			return wxString::Format(wxT("%02X:%02X:%02X:%02X:%02X:%02X"),
				(unsigned int)result[0], (unsigned int)result[1], (unsigned int)result[2],
				(unsigned int)result[3], (unsigned int)result[4], (unsigned int)result[5]);
		}
		return wxEmptyString;
	}
};

#endif

Sample of usage:

m_MACAddress = wxMACAddressUtility::GetMACAddress();

As you can see, core class does not depend on wxWidgets and can be used in native applications written without wxWidgets.

Download sample application