docs: def get_if_raw_hwaddr(ifname):
      """Returns the packed MAC address configured on 'ifname'."""
  
      NULL_MAC_ADDRESS = b'\x00' * 6
  
      # Handle the loopback interface separately
      if ifname == LOOPBACK_NAME:
          return (ARPHDR_LOOPBACK, NULL_MAC_ADDRESS)
  
      # Get ifconfig output
      try:
          fd = os.popen("%s %s" % (conf.prog.ifconfig, ifname))
      except OSError as msg:
          raise Scapy_Exception("Failed to execute ifconfig: (%s)" % msg)
  
      # Get MAC addresses
      addresses = [l for l in fd.readlines() if l.find("ether") >= 0 or
                   l.find("lladdr") >= 0 or
                   l.find("address") >= 0]
      if not addresses:
          raise Scapy_Exception("No MAC address found on %s !" % ifname)
  
      # Pack and return the MAC address
      mac = addresses[0].split(' ')[1]
      mac = [chr(int(b, 16)) for b in mac.split(':')]
      return (ARPHDR_ETHER, ''.join(mac))