Internal" (IP as bytes, mask as int) to "machine"
        representation.

def i2m(self, pkt, i):
        """"Internal" (IP as bytes, mask as int) to "machine"
        representation."""
        mask, ip = i
        ip = socket.inet_aton(ip)
        return struct.pack(">B", mask) + ip[:self.mask2iplen(mask)]