RTM_NEXTHOP_INFO

using System;
using System.Runtime.InteropServices;

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
public struct RTM_NET_ADDRESS
{
    public ushort AddressFamily;
    public ushort NumBits;
    [MarshalAs(UnmanagedType.ByValArray, SizeConst = 16)] public byte[] AddrBits;
}

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
public struct RTM_NEXTHOP_INFO
{
    public RTM_NET_ADDRESS NextHopAddress;
    public IntPtr NextHopOwner;
    public uint InterfaceIndex;
    public ushort State;
    public ushort Flags;
    public IntPtr EntitySpecificInfo;
    public IntPtr RemoteNextHop;
}

Imports System.Runtime.InteropServices

<StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Unicode)>
Public Structure RTM_NET_ADDRESS
    Public AddressFamily As UShort
    Public NumBits As UShort
    <MarshalAs(UnmanagedType.ByValArray, SizeConst:=16)> Public AddrBits() As Byte
End Structure

<StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Unicode)>
Public Structure RTM_NEXTHOP_INFO
    Public NextHopAddress As RTM_NET_ADDRESS
    Public NextHopOwner As IntPtr
    Public InterfaceIndex As UInteger
    Public State As UShort
    Public Flags As UShort
    Public EntitySpecificInfo As IntPtr
    Public RemoteNextHop As IntPtr
End Structure

import ctypes
from ctypes import wintypes

class RTM_NET_ADDRESS(ctypes.Structure):
    _fields_ = [
        ("AddressFamily", ctypes.c_ushort),
        ("NumBits", ctypes.c_ushort),
        ("AddrBits", ctypes.c_ubyte * 16),
    ]

class RTM_NEXTHOP_INFO(ctypes.Structure):
    _fields_ = [
        ("NextHopAddress", RTM_NET_ADDRESS),
        ("NextHopOwner", ctypes.c_ssize_t),
        ("InterfaceIndex", wintypes.DWORD),
        ("State", ctypes.c_ushort),
        ("Flags", ctypes.c_ushort),
        ("EntitySpecificInfo", ctypes.c_void_p),
        ("RemoteNextHop", ctypes.c_ssize_t),
    ]

#[repr(C)]
pub struct RTM_NET_ADDRESS {
    pub AddressFamily: u16,
    pub NumBits: u16,
    pub AddrBits: [u8; 16],
}

#[repr(C)]
pub struct RTM_NEXTHOP_INFO {
    pub NextHopAddress: RTM_NET_ADDRESS,
    pub NextHopOwner: isize,
    pub InterfaceIndex: u32,
    pub State: u16,
    pub Flags: u16,
    pub EntitySpecificInfo: *mut core::ffi::c_void,
    pub RemoteNextHop: isize,
}

import "golang.org/x/sys/windows"

type RTM_NET_ADDRESS struct {
	AddressFamily uint16
	NumBits uint16
	AddrBits [16]byte
}

type RTM_NEXTHOP_INFO struct {
	NextHopAddress RTM_NET_ADDRESS
	NextHopOwner uintptr
	InterfaceIndex uint32
	State uint16
	Flags uint16
	EntitySpecificInfo uintptr
	RemoteNextHop uintptr
}

type
  RTM_NET_ADDRESS = record
    AddressFamily: Word;
    NumBits: Word;
    AddrBits: array[0..15] of Byte;
  end;

  RTM_NEXTHOP_INFO = record
    NextHopAddress: RTM_NET_ADDRESS;
    NextHopOwner: NativeInt;
    InterfaceIndex: DWORD;
    State: Word;
    Flags: Word;
    EntitySpecificInfo: Pointer;
    RemoteNextHop: NativeInt;
  end;

const RTM_NET_ADDRESS = extern struct {
    AddressFamily: u16,
    NumBits: u16,
    AddrBits: [16]u8,
};

const RTM_NEXTHOP_INFO = extern struct {
    NextHopAddress: RTM_NET_ADDRESS,
    NextHopOwner: isize,
    InterfaceIndex: u32,
    State: u16,
    Flags: u16,
    EntitySpecificInfo: ?*anyopaque,
    RemoteNextHop: isize,
};

type
  RTM_NET_ADDRESS {.bycopy.} = object
    AddressFamily: uint16
    NumBits: uint16
    AddrBits: array[16, uint8]

  RTM_NEXTHOP_INFO {.bycopy.} = object
    NextHopAddress: RTM_NET_ADDRESS
    NextHopOwner: int
    InterfaceIndex: uint32
    State: uint16
    Flags: uint16
    EntitySpecificInfo: pointer
    RemoteNextHop: int

struct RTM_NET_ADDRESS
{
    ushort AddressFamily;
    ushort NumBits;
    ubyte[16] AddrBits;
}

struct RTM_NEXTHOP_INFO
{
    RTM_NET_ADDRESS NextHopAddress;
    ptrdiff_t NextHopOwner;
    uint InterfaceIndex;
    ushort State;
    ushort Flags;
    void* EntitySpecificInfo;
    ptrdiff_t RemoteNextHop;
}