MessageBox Hook - Dll File

#include <windows.h>
#include <fstream>

#define SIZE 6

typedef int (WINAPI *pMessageBoxA)(HWND, LPCSTR, LPCSTR, UINT); // typedef the FuncVairable[Fake-Reall]
int WINAPI MyMessageBoxA(HWND, LPCSTR, LPCSTR, UINT); // Fake Function

void BeginRedirect(LPVOID);

pMessageBoxA pOrigMBAddress = NULL; //  RealFunction
BYTE oldBytes[SIZE] = {0}; // To Hae the backup for unhook
BYTE JMP[SIZE] = {0}; // To have the jmp
DWORD oldProtect, myProtect = PAGE_EXECUTE_READWRITE;

INT APIENTRY DllMain(HMODULE hDLL, DWORD Reason, LPVOID Reserved)
{
    switch(Reason)
    {

    case DLL_PROCESS_ATTACH:  // if library loaded
        pOrigMBAddress = (pMessageBoxA)GetProcAddress(GetModuleHandle(TEXT("user32.dll")), "MessageBoxA");
        //Get Address of Function "MessageBoxA" and put it in varibal of pointer for a WIN API

        if(pOrigMBAddress != NULL) // if every thing ok >
            BeginRedirect(MyMessageBoxA);    // Start hooking
        break;

    case DLL_PROCESS_DETACH: // if library unload // and unhook
        memcpy(pOrigMBAddress, oldBytes, SIZE); // but the reall function addres into the reall function
    case DLL_THREAD_ATTACH:
    case DLL_THREAD_DETACH:
        break;
    }
    return TRUE;
}

void BeginRedirect(LPVOID newFunction)
{
    ///// TheJumpCode     JMP     x     x    x     x    RET
    BYTE tempJMP[SIZE] = {0xE9, 0x09,0x09,0x09,0x09, 0xC3}; // this is assambly code for jamp to address of fuck function (JMP NOP NOP RET)

        memcpy(JMP, tempJMP, SIZE); /////  Copy Bytes Array Form JMP to tempJMP

    // Get fake function address  ==>
    //                 FakeFunctionAddr  -   ReallFunctionAddr  - 5
    DWORD JMPSize = ((DWORD)newFunction - (DWORD)pOrigMBAddress - 5);
    // Allowed the realfunction vairable to write and read   and   get  the oldProtect
    VirtualProtect((LPVOID)pOrigMBAddress, SIZE,  PAGE_EXECUTE_READWRITE, &oldProtect);

    // BackUp the reallFunc addrs into oldBytes
    memcpy(oldBytes, pOrigMBAddress, SIZE); // Put pOrigMBAddress

    // Chane the - JMP [ x   x   x   x ] RET -
    //    To the        fakeFunc addrs
    memcpy(&JMP[1], &JMPSize,4);

    // Chane the reallFunction addres to the [ JMP ] code
    memcpy(pOrigMBAddress, JMP, SIZE);

    // Retrun the oldProtect
    VirtualProtect((LPVOID)pOrigMBAddress, SIZE, oldProtect, NULL);
}

int  WINAPI MyMessageBoxA(HWND hWnd, LPCSTR lpText, LPCSTR lpCaption, UINT uiType)
{
    //   Allowed the reallFunction Vairable to wrtie - read - execute
    VirtualProtect((LPVOID)pOrigMBAddress, SIZE, myProtect, NULL);

    // Copy the oldBytes(the realFunc addrs) to the ReallFunc Vairable
    memcpy(pOrigMBAddress, oldBytes, SIZE);

    // Execute what ever you want ->
        Beep(1000,1000);
     MessageBoxA(hWnd, "ServatonSecure", "Hooked", uiType);


    // Return the JMP
    memcpy(pOrigMBAddress, JMP, SIZE);

    // Return the oldProtect
    VirtualProtect((LPVOID)pOrigMBAddress, SIZE, oldProtect, NULL);

    // Return value to the user :)
    return 0;
}