broardcast.cpp

网络技术

// broardcast.cpp : Defines the entry point for the application.
//

#include "stdafx.h"
#include "resource.h"

#include <winsock.h>
#pragma comment(lib, "Ws2_32.lib")
#define PORT 8888
#define MAX_LENGTH 256
#define MY_SOCK WM_USER+0x100

#define MAX_LOADSTRING 100
// Global Variables:
HINSTANCE hInst;								// current instance
TCHAR szTitle[MAX_LOADSTRING];								// The title bar text
TCHAR szWindowClass[MAX_LOADSTRING];								// The title bar text

// Foward declarations of functions included in this code module:
ATOM				MyRegisterClass(HINSTANCE hInstance);
BOOL				InitInstance(HINSTANCE, int);
LRESULT CALLBACK	WndProc(HWND, UINT, WPARAM, LPARAM);
LRESULT CALLBACK	About(HWND, UINT, WPARAM, LPARAM);




LRESULT CALLBACK	Send(HWND, UINT, WPARAM, LPARAM);
//发送条处理函数
BOOL broadsend(TCHAR* buffer);			//发送函数
BOOL broadinit();						//初始化
BOOL broadrecv(TCHAR* buffer);			//接收函数
VOID broadclose();						//关闭套接字
BOOL broadselect(HWND hWnd, long lEvent);

TCHAR serveraddr[MAX_LENGTH];			//存放主机名
TCHAR FAR* lpServeraddr = serveraddr;
TCHAR ipaddr[MAX_LENGTH];				//存放主机ip地址信息
TCHAR FAR* lpIpaddr = ipaddr;

TCHAR recvBuffer[30][3*MAX_LENGTH];
TCHAR FAR* lpBuffer[30];				//消息缓冲队列
int rear = 0, front = 1;

SOCKET s = 0;							//套接字
struct sockaddr_in broadsock;			
struct hostent* hostaddr;				//在得到本机ip时要用到

int APIENTRY WinMain(HINSTANCE hInstance,
                     HINSTANCE hPrevInstance,
                     LPSTR     lpCmdLine,
                     int       nCmdShow)
{
 	// TODO: Place code here.
	MSG msg;
	HACCEL hAccelTable;

	// Initialize global strings
	LoadString(hInstance, IDS_APP_TITLE, szTitle, MAX_LOADSTRING);
	LoadString(hInstance, IDC_BROARDCAST, szWindowClass, MAX_LOADSTRING);
	MyRegisterClass(hInstance);

	// Perform application initialization:
	if (!InitInstance (hInstance, nCmdShow)) 
	{
		return FALSE;
	}

	hAccelTable = LoadAccelerators(hInstance, (LPCTSTR)IDC_BROARDCAST);

	// Main message loop:
	while (GetMessage(&msg, NULL, 0, 0)) 
	{
		if (!TranslateAccelerator(msg.hwnd, hAccelTable, &msg)) 
		{
			TranslateMessage(&msg);
			DispatchMessage(&msg);
		}
	}

	return msg.wParam;
}



//
//  FUNCTION: MyRegisterClass()
//
//  PURPOSE: Registers the window class.
//
//  COMMENTS:
//
//    This function and its usage is only necessary if you want this code
//    to be compatible with Win32 systems prior to the 'RegisterClassEx'
//    function that was added to Windows 95. It is important to call this function
//    so that the application will get 'well formed' small icons associated
//    with it.
//
ATOM MyRegisterClass(HINSTANCE hInstance)
{
	WNDCLASSEX wcex;

	wcex.cbSize = sizeof(WNDCLASSEX); 

	wcex.style			= CS_HREDRAW | CS_VREDRAW;
	wcex.lpfnWndProc	= (WNDPROC)WndProc;
	wcex.cbClsExtra		= 0;
	wcex.cbWndExtra		= 0;
	wcex.hInstance		= hInstance;
	wcex.hIcon			= LoadIcon(hInstance, (LPCTSTR)IDI_BROARDCAST);
	wcex.hCursor		= LoadCursor(NULL, IDC_ARROW);
	wcex.hbrBackground	= (HBRUSH)(COLOR_WINDOW+1);
	wcex.lpszMenuName	= (LPCSTR)IDC_BROARDCAST;
	wcex.lpszClassName	= szWindowClass;
	wcex.hIconSm		= LoadIcon(wcex.hInstance, (LPCTSTR)IDI_SMALL);

	return RegisterClassEx(&wcex);
}

//
//   FUNCTION: InitInstance(HANDLE, int)
//
//   PURPOSE: Saves instance handle and creates main window
//
//   COMMENTS:
//
//        In this function, we save the instance handle in a global variable and
//        create and display the main program window.
//
BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
   HWND hWnd;

   hInst = hInstance; // Store instance handle in our global variable

   hWnd = CreateWindow(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
      CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, hInstance, NULL);

   if (!hWnd)
   {
      return FALSE;
   }

   ShowWindow(hWnd, nCmdShow);
   UpdateWindow(hWnd);

   return TRUE;
}

//
//  FUNCTION: WndProc(HWND, unsigned, WORD, LONG)
//
//  PURPOSE:  Processes messages for the main window.
//
//  WM_COMMAND	- process the application menu
//  WM_PAINT	- Paint the main window
//  WM_DESTROY	- post a quit message and return
//
//

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
	int wmId, wmEvent;
	PAINTSTRUCT ps;
	HDC hdc;
	TCHAR szHello[MAX_LOADSTRING];
	LoadString(hInst, IDS_HELLO, szHello, MAX_LOADSTRING);
	
	int textX = 0, textY = 0;

	WSADATA wsaData;

	switch (message) 
	{
		
		case WM_CREATE:
			if(WSAStartup(0x101, &wsaData))
			{
				MessageBox(hWnd, "初始化Ws2_32.lib失败", "ERROR!", MB_OK);
				PostMessage(hWnd, WM_DESTROY, NULL, NULL);
			}//初始化Winsock动态链接库
			if(!broadinit())
			{	
				MessageBox(hWnd, "初始化Winsock失败", "ERROR!", MB_OK);
				PostMessage(hWnd, WM_DESTROY, NULL, NULL);
			}//初始化套接字
			if(!broadselect(hWnd, FD_READ))
			{
				MessageBox(hWnd, "异步选择失败", "ERROR!", MB_OK);
				PostMessage(hWnd, WM_DESTROY, NULL, NULL);
			}//参见原理部分的WSAAsyncSocket的用法

			gethostname(lpServeraddr, MAX_LENGTH);
			//得到主机名
			hostaddr = gethostbyname(lpServeraddr);
			//通过主机名得到ip等一系列信息
			lpIpaddr=inet_ntoa (*(struct in_addr *)hostaddr->h_addr_list[0]);
			//将四字节ip格式化为字符窜
			int j;
			for(j = 0; j<30; j++)
			{
				lpBuffer[j] = recvBuffer[j];
				memset(lpBuffer[j], 0, 3*MAX_LENGTH);
			}
			//初始化消息缓冲区
			//MessageBox(hWnd, lpIpaddr, "", 0);

			break;
		case WM_COMMAND:
			wmId    = LOWORD(wParam); 
			wmEvent = HIWORD(wParam); 
			switch (wmId)
			{
				case IDM_ABOUT:
				   DialogBox(hInst, (LPCTSTR)IDD_ABOUTBOX, hWnd, (DLGPROC)About);
				   break;
				case IDM_EXIT:
				   DestroyWindow(hWnd);
				   break;
				case IDM_SEND:
					DialogBox(hInst, (LPCTSTR)IDD_BROAD, hWnd, (DLGPROC)Send);
					break;
				default:
				   return DefWindowProc(hWnd, message, wParam, lParam);
			}
			break;

		case MY_SOCK:
			switch(lParam)
			{
				case FD_READ:
					//得到数据到达的消息，便启动broadrecv接收
					if(!broadrecv(lpBuffer[rear]))
						MessageBox(hWnd, "接收失败!", "ERROR!", MB_OK);
					else
					{
						if(front<29)	front++;
						else			front=0;
						memset(lpBuffer[front], 0, 3*MAX_LENGTH);
						if(rear<29)	rear++;
						else		rear=0;
						//以上是对消息缓存队列的操作
						//其原理是循环队列，超过30条记录就把第一条擦掉
						
					}
					InvalidateRect(hWnd, NULL, TRUE);
					break;
				default:
					break;
			}
			break;
		case WM_PAINT:
			hdc = BeginPaint(hWnd, &ps);
			RECT rt;
			GetClientRect(hWnd, &rt);
			DrawText(hdc, szHello, strlen(szHello), &rt, DT_CENTER);
			//以下为将暂存消息队列中的字符窜输出到窗口中
			int i;
			for(i = 0; i<30; i++)
				TextOut(hdc, 0, 20*i+20, lpBuffer[i], strlen(lpBuffer[i]));
			EndPaint(hWnd, &ps);
			break;
		case WM_DESTROY:
			broadclose();
			WSACleanup();
			PostQuitMessage(0);
			break;

		default:
			return DefWindowProc(hWnd, message, wParam, lParam);
   }
   return 0;
}

LRESULT CALLBACK About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)
{
	switch (message)
	{
		case WM_INITDIALOG:
				return TRUE;

		case WM_COMMAND:
			if (LOWORD(wParam) == IDOK || LOWORD(wParam) == IDCANCEL) 
			{
				EndDialog(hDlg, LOWORD(wParam));
				return TRUE;
			}
			break;
	}
    return FALSE;
}


LRESULT CALLBACK Send(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)
{
	//这个是发送内容对话框的处理程序
	switch (message)
	{
		case WM_INITDIALOG:
				return TRUE;

		case WM_COMMAND:
			if (LOWORD(wParam) == ID_CANCEL) 
			{
				EndDialog(hDlg, LOWORD(wParam));
				return TRUE;
			}
			if (LOWORD(wParam) == ID_SEND)
			{
				//如果点击了发送按钮，就把文本框中的内容加上ip和主机信息发送
				TCHAR content[MAX_LENGTH];
				GetDlgItemText(hDlg, IDC_CONTENT, content, MAX_LENGTH);
				TCHAR sendBuffer[768] = {0};
				//以下为格式化字符窜
				wsprintf(sendBuffer, "主机:%s,IP%s,广播:%s", lpServeraddr, lpIpaddr, content);
				if(!broadsend(sendBuffer))
					MessageBox(hDlg, "发送失败!", "ERROR!", MB_OK);
				EndDialog(hDlg, LOWORD(wParam));
			}
			break;
	}
    return FALSE;
}


BOOL broadsend(TCHAR* buffer)
{
	struct sockaddr_in target;
	target.sin_family = AF_INET;
	target.sin_addr.S_un.S_addr = INADDR_BROADCAST;
	target.sin_port = htons(PORT);
	//以上是填充目标地址块
	if((sendto(s, buffer, 3*MAX_LENGTH, 0, (struct sockaddr FAR*)&target,
		sizeof(SOCKADDR))) == SOCKET_ERROR)
		return FALSE;
	//发送数据buffer
	return TRUE;
}


BOOL broadinit()
{
	BOOL optval = TRUE;
	if((s = socket(AF_INET, SOCK_DGRAM, 0)) == INVALID_SOCKET)
		return FALSE;
	//初始化套接字s，记住，只有SOCK_DGRAM(无连接方式)才支持广播
	broadsock.sin_family = AF_INET;
	broadsock.sin_addr.S_un.S_addr = 0;
	broadsock.sin_port = htons(PORT);
	//填充本机地址块，其中PORT为8888
	if(bind(s, (LPSOCKADDR)&broadsock, sizeof(broadsock)))
		return FALSE;
	//绑定端口
	if(setsockopt(s, SOL_SOCKET, SO_BROADCAST, (char FAR*)&optval, 
		sizeof(optval)) == SOCKET_ERROR)
	//记住，这一步将套接字设为可以广播的格式
		return FALSE;
	return TRUE;
}

BOOL broadrecv(TCHAR* buffer)
{
	int errno, len;
	
	int from_len = sizeof(SOCKADDR);
	struct sockaddr_in from;

	if((len = recvfrom(s, buffer, 3*MAX_LENGTH, 0, (struct sockaddr FAR*)&from,
		(int FAR*)&from_len)) == SOCKET_ERROR)
	{
		errno = WSAGetLastError();
		//上面这种方式是网络编程常用的方法
		//针对错误码进行不同的处理，可以使程序更强壮
		if(errno == WSAEWOULDBLOCK)
		//套接字定为非阻塞，但接收操作将被阻塞
			return TRUE;
		else {						//发生错误
			broadclose();
			return FALSE;
		}
	}
	if(len == 0)
	{
		return FALSE;				//接收错误
	}
	return TRUE;
}


VOID broadclose()
{
	if(s){
		closesocket(s);
		//关闭套接字
		s = 0;
	}
}

BOOL broadselect(HWND hWnd, long lEvent)
{
	if(WSAAsyncSelect(s, hWnd, MY_SOCK, lEvent) == SOCKET_ERROR) {
	//WSAAsyncSelect的用处非常大，具体的说明详见实验原理部分
		return FALSE;
	}
	return TRUE;
}