def METHOD_NAME(child, netif):
    hwaddrs = []
    child.sendline("ifconfig {}".format(netif))
    child.expect(r"HWaddr:\s+(([A-Fa-f0-9]{2}:?)+)\s")
    hwaddrs.append(child.match.group(1).lower())
    if len(hwaddrs[0]) == 5:    # short address
        res = child.expect([pexpect.TIMEOUT,
                            r"Long HWaddr:\s+(([A-Fa-f0-9]{2}:?)+)\s"])
        if res > 0:
            hwaddrs.append(child.match.group(1).lower())
    return hwaddrs