Read MAC address on VxWorks 6.8

[MotoDev]

I am attempting to read the MAC address of my device on VxWorks 6.8.

Back on Vx5.5, I was able to do this:
char macAddress[6];
STATUS ret = ERROR;
void * pDrvCookie = muxTkCookieGet(LAN_IF_NAME, LAN_IF_NUMBER);
if( pDrvCookie == NULL )
return ERROR;
else
ret = muxIoctl( pDrvCookie, EIOCGADDR, macAddress);

However, now I'm on 6.8, and it returns an error code of 22 ("Invalid argument").
I suspect it is because I am using the old header file with the definition of EIOCGADDR. But, I don't have the new header.

So... my question is:
1) Can someone post the definition of EIOCGADDR ("end.h").
- OR -
2) Can someone suggest an alternate method to obtain the MAC address. I have already tried the following, with no success:
ifunit <- not defined
etherAddrResolve(self) <- not defined
arpResolve(self) <- doesn't work when using my own IP address, "Network is unreachable"

Thanks.