Hop-by-Hop, Destination option header structures consist of 2 unsigned char; next option type and header length field. And TLV(Type-Length-Value) option headers come by the number in header length field. If the option type in TLV option header is not recognized and 2 MSB is not 0, it is handled as an exception. Signed-off-by: goldsimon <goldsimon@gmx.de>