type ty = | Echo_reply| Destination_unreachable| Source_quench| Redirect| Echo_request| Time_exceeded| Parameter_problem| Timestamp_request| Timestamp_reply| Information_request| Information_reply
val ty_to_string : ty -> stringval int_to_ty : int -> ty optionval ty_to_int : ty -> inttype unreachable_reason = | Network_unreachable| Host_unreachable| Protocol_unreachable| Port_unreachable| Would_fragment| Source_route_failed| Destination_network_unknown| Destination_host_unknown| Source_host_isolated| Destination_net_prohibited| Destination_host_prohibited| TOS_network_unreachable| TOS_host_unreachable| Communication_prohibited| Host_precedence_violation| Precedence_insufficient
val get_ty : Cstruct.t -> intval set_ty : Cstruct.t -> int -> unitval get_code : Cstruct.t -> intval set_code : Cstruct.t -> int -> unitval get_checksum : Cstruct.t -> intval set_checksum : Cstruct.t -> int -> unit