# 缘由

对接供应商时需要提供一个 27 服务的安全解密算法 dll，于是学了一下 vs 批处理生成 C++ 模板的 dll，并使用 C++ 或者 C# 调用 dll 来验证，虽然其中结果有点曲折。难点主要是 C++ 到 C# 数据类型的映射，这个是最麻烦的。

# DLL 封装

UDS 27 服务需要用到安全算法 dll 解密。这里使用的模板是 Canoe 的 dll 生成模板，但是模板代码使用的是 Diva 里的模板代码，模板可以去 vector 官网下载 demo 版，以下是粗略的步骤。

	#include <iostream>
	#include <Windows.h>
	#include <tchar.h>

	enum VKeyGenResultEx {
	KGRE_Ok = 0,
	KGRE_BufferToSmall = 1,
	KGRE_SecurityLevelInvalid = 2,
	KGRE_VariantInvalid = 3,
	KGRE_UnspecifiedError = 4
	};

	int main() {
	// loading dll handler
	HINSTANCE handle = LoadLibrary(_T("GenerateYourself.dll"));

	// get error code if dll handler is not found
	if (0 == handle) {
	std::cout << "dll handle result value:"<< handle <<"\n";
	std::cout<< GetLastError() <<std::endl;
	}
	// caluate $27 server key
	else {
	// define function pointers
	typedef VKeyGenResultEx(DLL_FUNCTION_GENERATEKEYEX) (const unsigned char, unsigned int,
	const unsigned int, const char*,
	unsigned char*, unsigned int,
	unsigned int&);

	// rename dll_GenerateKeyEx from GenerateKeyEx
	DLL_FUNCTION_GENERATEKEYEX dll_GenerateKeyEx = (DLL_FUNCTION_GENERATEKEYEX)GetProcAddress(handle, "GenerateKeyEx");
	std::cout << "dll handle result value:" << handle << "\n";

	if (dll_GenerateKeyEx) {
	unsigned char seed[4] = {your_seed};
	unsigned int seedSize = 4;
	unsigned int SecurityLevel = YourSecurityLevel;
	char ipVariant[4] = "123";
	unsigned char key[4] = {0};
	unsigned int maxKeySize = 4;
	unsigned int KeySize = 4;

	dll_GenerateKeyEx(seed, seedSize, SecurityLevel,
	ipVariant, key, maxKeySize, KeySize);

	std::cout << "seed: ";
	for (int i = 0; i < sizeof(seed); i++) {
	std::cout << std::hex <<(int)seed[i] << " ";
	}
	std::cout << "\nkey: ";
	for (int i = 0; i < sizeof(key); i++) {
	std::cout << std::hex <<(int)key[i] << " ";
	}

	FreeLibrary(handle); //free handle
	}
	}
	return 0;
	}

注，该代码只能调用 X64 的 DLL，不能调用 32 位的 DLL，推测是因为计算机是 64 位的原因，目前 32 位的 DLL 怎么调用暂时没找到方法。

	using System;
	using System.Runtime.InteropServices;

	namespace CallTheDll01
	{
	class Program
	{
	public enum VKeyGenResultEx {
	KGRE_Ok = 0,
	KGRE_BufferToSmall = 1,
	KGRE_SecurityLevelInvalid = 2,
	KGRE_VariantInvalid = 3,
	KGRE_UnspecifiedError = 4
	};
	// must use CallingConvention.Cdecl，otherwise program will error
	[DllImport("GenerateYourself.dll", CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Unicode)]

	public static extern VKeyGenResultEx GenerateKeyEx(Byte[] ipSeedArray, UInt32 iSeedArraySize,
	UInt32 iSecurityLevel, String ipVariant,
	Byte[] iopKeyArray, UInt32 iMaxKeyArraySize,
	ref UInt32 oActualKeyArraySize);
	static void Main(string[] args) {

	// Byte 为 8 位的无符号整数类型，范围为 0~255，默认显示十进制
	Byte[] seed = {your_seed};
	UInt32 seedSize = 4;
	UInt32 SecurityLevel = YourSecurityLevel;
	String ipVariant = "123";
	Byte[] key = {0x0, 0x0, 0x0, 0x0};
	UInt32 maxKeySize = 4;
	UInt32 KeySize = 4;
	GenerateKeyEx(seed, seedSize, SecurityLevel, ipVariant, key, maxKeySize, ref KeySize);

	Console.WriteLine("seed: " + BitConverter.ToString(seed).Replace("-", " "));
	Console.WriteLine("key: " + BitConverter.ToString(key).Replace("-", " "));
	// Console.ReadKey();
	}
	}
	}

这里 C# 调用 DLL 使用的是 P/Invoke 方法，另外还有两种方法，不过不太想了解了。

注：这 C# 鬼东西花了我一天时间才弄完，主要是 C++ 到 C# 数据类型映射这一块，真的有大坑，不过我不跳，哈哈。