// Based on example code from https://msdn.microsoft.com/en-us/library/windows/desktop/aa365947(v=vs.85).aspx
// and http://www.nynaeve.net/Code/GetInterfaceMetric.cpp.

#include <winsock2.h>
#include <ws2ipdef.h>
#include <iphlpapi.h>
#include <stdio.h>
#include <objbase.h>

#pragma comment(lib, "iphlpapi.lib")
#pragma comment(lib, "Ole32.lib")

#define MALLOC(x) HeapAlloc(GetProcessHeap(), 0, (x)) 
#define FREE(x) HeapFree(GetProcessHeap(), 0, (x))

/* Note: could also use malloc() and free() */

//
// Suspected prototype of NsiGetParameter, via reverse engineering.
//

typedef DWORD (__stdcall *NsiGetParameterProc)(
  DWORD        Argument1,
  CONST UCHAR* Argument2,
  DWORD        Argument3,
  PNET_LUID    Argument4,
  DWORD        Argument5,
  DWORD        Argument6,
  PUCHAR       Argument7,
  DWORD        Argument8,
  DWORD        Argument9
  );

/*
0:000> db NPI_MS_IPV4_MODULEID l14
751b3364  18 00 00 00 01 00 00 00-00 4a 00 eb 1a 9b d4 11
751b3374  91 23 00 50 04 77 59 BC
*/

const unsigned char NPI_MS_IPV4_MODULEID[0x18] =
{
  0x18, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x4A, 0x00, 0xEB, 0x1A, 0x9B, 0xD4, 0x11,
  0x91, 0x23, 0x00, 0x50, 0x04, 0x77, 0x59, 0xBC
};

VOID PrintHex(PBYTE Data, ULONG dwBytes) {
  for (ULONG i = 0; i < dwBytes; i += 16) {
    printf("%.8x: ", i);

    for (ULONG j = 0; j < 16; j++) {
      if (i + j < dwBytes) {
        printf("%.2x ", Data[i + j]);
      }
      else {
        printf("?? ");
      }
    }

    for (ULONG j = 0; j < 16; j++) {
      if (i + j < dwBytes && Data[i + j] >= 0x20 && Data[i + j] <= 0x7e) {
        printf("%c", Data[i + j]);
      }
      else {
        printf(".");
      }
    }

    printf("\n");
  }
}

int main() {
  HMODULE hNsi = LoadLibraryW(L"Nsi.dll");
  NsiGetParameterProc _NsiGetParameter = (NsiGetParameterProc)GetProcAddress(hNsi, "NsiGetParameter");

  // Declare and initialize variables
  PIP_INTERFACE_INFO pInfo = NULL;
  ULONG ulOutBufLen = 0;

  DWORD dwRetVal = 0;
  int iReturn = 1;

  int i;

  // Make an initial call to GetInterfaceInfo to get
  // the necessary size in the ulOutBufLen variable
  dwRetVal = GetInterfaceInfo(NULL, &ulOutBufLen);
  if (dwRetVal == ERROR_INSUFFICIENT_BUFFER) {
    pInfo = (IP_INTERFACE_INFO *)MALLOC(ulOutBufLen);
    if (pInfo == NULL) {
      printf
        ("Unable to allocate memory needed to call GetInterfaceInfo\n");
      return 1;
    }
  }
  // Make a second call to GetInterfaceInfo to get
  // the actual data we need
  dwRetVal = GetInterfaceInfo(pInfo, &ulOutBufLen);
  if (dwRetVal == NO_ERROR) {
    printf("Number of Adapters: %ld\n\n", pInfo->NumAdapters);
    for (i = 0; i < pInfo->NumAdapters; i++) {
      printf("Adapter Index[%d]: %ld\n", i,
        pInfo->Adapter[i].Index);

      NET_LUID Luid;
      NETIO_STATUS st = ConvertInterfaceIndexToLuid(pInfo->Adapter[i].Index, &Luid);
      if (st == NO_ERROR) {
        BYTE OutputBuffer[0xB8] = { /* zero padding */ };
        DWORD nsi_st = _NsiGetParameter(1, NPI_MS_IPV4_MODULEID, 7, &Luid, sizeof(Luid), 0, OutputBuffer, sizeof(OutputBuffer), 0);
        if (nsi_st == NO_ERROR) {
          PrintHex(OutputBuffer, sizeof(OutputBuffer));
        }
      }
    }
    iReturn = 0;
  }
  else if (dwRetVal == ERROR_NO_DATA) {
    printf
      ("There are no network adapters with IPv4 enabled on the local system\n");
    iReturn = 0;
  }
  else {
    printf("GetInterfaceInfo failed with error: %d\n", dwRetVal);
    iReturn = 1;
  }

  FREE(pInfo);
  return (iReturn);
}