val get_checksum : Cstruct.t -> Cstruct.uint16
val set_checksum : Cstruct.t -> Cstruct.uint16 -> unit
val cur_hop_limit_off : int
val get_cur_hop_limit : Cstruct.t -> Cstruct.uint8
val router_lifetime_off : int
val get_router_lifetime : Cstruct.t -> Cstruct.uint16
val reachable_time_off : int
val get_reachable_time : Cstruct.t -> Cstruct.uint32
val retrans_timer_off : int
val get_retrans_timer : Cstruct.t -> Cstruct.uint32