IEEE OUI Display on host/details about kvasir HOT 3 CLOSED

def oui_lookup(mac_addr='00:00:00:00:00:00', nmap_os_db='/usr/local/share/nmap/nmap-mac-prefixes'):
    """
    Lookup a vendor from the Nmap MAC Prefixes file

    >>> oui_lookup('00:00:00:00:00:00')
    'Xerox'
    >>> oui_lookup('00-00-00-00-00-00')
    'Xerox'
    >>> oui_lookup(-1)
    'Unknown'
    >>> oui_lookup('00:00:00:00:00:00', nmap_os_db='/zxvkjaiwe/9234123/zxcvzxvsadf')
    'Unknown'
    """
    import os
    import mmap

    try:
        oui_fs = open(nmap_os_db, "r")
    except IOError, err:
        return dict(mac_addr='Unknown')

    oui_data = mmap.mmap(oui_fs.fileno(), 0, access=mmap.ACCESS_READ)
    def _lookup(mac_addr, oui_data):
        oui_result = 'Unknown'
        # remove : or - or just accept it as is and be lucky
        if mac_addr.find(':') > -1:
            mac_lookup = "".join(mac_addr.split(':')[:3])
        else:
            mac_lookup = "".join(mac_addr.split('-')[:3])

        if len(mac_lookup) == 6:
            # MAC addresses in nmap db are in upper case and we want start of line (post \n)
            location = oui_data.find('\n' + mac_lookup.upper())
            location += 1   # remove leading \n
            if location > 0:
                oui_result = oui_data[location+7:location+oui_data[location:].find('\n')]

        return oui_result

    result = {}
    if isinstance(mac_addr, list):
        for addr in mac_addr:
            result[addr] = _lookup(addr, oui_data)

    if isinstance(mac_addr, str):
        result[mac_addr] = _lookup(mac_addr, oui_data)

    return result