vc6.0 MFC 先用udp广播，再client建立连接，新手求大神解答

[huangpan_123]

delphi 里面是
IdudpServer1.Broadcast('EASYNET',120); //广播

IdUDPServer1UDPRead 事件里：
IP := ABinding.PeerIP; //获取设备ip端口
port := ABinding.port;

按钮事件里：
ClientSocket1.Active:=False; //建立连接
ClientSocket1.Host:=IP;
ClientSocket1.Port:=120;
ClientSocket1.Active:=True;


用MFC怎么实现啊。。

我现在 MFC 里面 最基础的广播 都有点问题啊:

CString msg = "EASYNET";
SOCKADDR_IN addr;

int broad = 1;

SOCKET fd = socket(AF_INET,SOCK_DGRAM,0);

setsockopt(fd,SOL_SOCKET,SO_BROADCAST,(const char *)&broad,sizeof(broad));

addr.sin_addr.S_un.S_addr= INADDR_BROADCAST;

addr.sin_family = AF_INET;

addr.sin_port = htons(120);

sendto(fd,msg,strlen(msg)+1,0,(SOCKADDR *)&addr,sizeof(SOCKADDR));

[huangpan_123]

OK连接问题 解决了，我调试下，，

[qq_18356739]

udp广播成功以后，怎么获取到应答的 对象IP 就像 dlphi 里的 IdUDPServer1UDPRead 事件： IP := ABinding.PeerIP; //获取设备ip端口 port := ABinding.port;

[huangpan_123]

SOCKET sock; //socket套接字 unsigned long ip; char szMsg[] = "EASYNET";//被发送的字段 WORD wVersionRequested; //1.启动SOCKET库，版本为2.0 WSADATA wsaData; int err; wVersionRequested = MAKEWORD( 2, 0 ); err = WSAStartup( wVersionRequested, &wsaData ); if ( 0 != err ) //检查Socket初始化是否成功 { MessageBox("Socket2.0初始化失败，Exit!");//<<"Socket2.0初始化失败，Exit!"; return; } if (LOBYTE( wsaData.wVersion ) != 2 || HIBYTE( wsaData.wVersion ) != 0 )//检查Socket库的版本是否为2.0 { WSACleanup( ); return; } sock = socket( //2.创建socket， AF_INET, //internetwork: UDP, TCP, etc SOCK_DGRAM, //SOCK_DGRAM说明是UDP类型 0 //protocol ); if (INVALID_SOCKET == sock ) { MessageBox("Socket 创建失败，Exit!");//cout<<"Socket 创建失败，Exit!"; return; } bool opt = true; setsockopt(sock, SOL_SOCKET, SO_BROADCAST, reinterpret_cast<char FAR *>(&opt), sizeof(opt));//3.设置该套接字为广播类型 sockaddr_in addrto; //设置发往的地址 memset(&addrto,0,sizeof(addrto)); addrto.sin_family = AF_INET; //地址类型为internetwork addrto.sin_addr.s_addr = INADDR_BROADCAST; //设置ip为广播地址 addrto.sin_port = htons(120); //端口号为120 bind(sock,(SOCKADDR*)&addrto,sizeof(addrto));//绑定 int nlen=sizeof(addrto); unsigned int uIndex = 1; while(true) { Sleep(1000); //程序休眠一秒 if( sendto(sock, szMsg, strlen(szMsg), 0, (sockaddr*)&addrto,nlen)== SOCKET_ERROR )//广播 MessageBox((LPCTSTR)WSAGetLastError); else { MessageBox( "an UDP package is sended."); //接收数据 CHAR szBuff[100]={0}; SOCKADDR_IN clientAddr={0}; int nLen=sizeof(clientAddr); recvfrom(sock,szBuff,100,0,(SOCKADDR*)&clientAddr,&nLen); ip = clientAddr.sin_addr.S_un.S_addr; MessageBox((LPCTSTR)ip); } } if (!closesocket(sock)) //关闭套接字 { WSAGetLastError(); return; } if (!WSACleanup()) //关闭Socket库 { WSAGetLastError(); return; } 这个是UDP 广播 我怎么获取广播后对方的IP ，我的band和 recvfrom是不是有问题?

[huangpan_123]

[oyljerry]

广播后是什么问题，抓包分析一下

[Eleven]

SOCKADDR_IN addr = {0};
	SOCKET sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
	if(INVALID_SOCKET == sock)
	{
		goto __CLEANUP__;
	}

	addr.sin_family = AF_INET;
	addr.sin_addr.S_un.S_addr = htonl(INADDR_BROADCAST);
	addr.sin_port = htons(DEFAULT_BROADCAST_PORT);
	BOOL bBroadcast = TRUE;

	if(SOCKET_ERROR == setsockopt(sock, SOL_SOCKET, SO_BROADCAST, (char*)&bBroadcast, sizeof(bBroadcast)))
	{
		goto __CLEANUP__;
	}

if(SOCKET_ERROR == sendto(sock, (char*)szIpAddress, sizeof(szIpAddress), 0, (LPSOCKADDR)&addr, sizeof(addr)))
					{

					}

[qq_18239273]

引用 5 楼 VisualEleven 的回复:

SOCKADDR_IN addr = {0};
	SOCKET sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
	if(INVALID_SOCKET == sock)
	{
		goto __CLEANUP__;
	}

	addr.sin_family = AF_INET;
	addr.sin_addr.S_un.S_addr = htonl(INADDR_BROADCAST);
	addr.sin_port = htons(DEFAULT_BROADCAST_PORT);
	BOOL bBroadcast = TRUE;

	if(SOCKET_ERROR == setsockopt(sock, SOL_SOCKET, SO_BROADCAST, (char*)&bBroadcast, sizeof(bBroadcast)))
	{
		goto __CLEANUP__;
	}

if(SOCKET_ERROR == sendto(sock, (char*)szIpAddress, sizeof(szIpAddress), 0, (LPSOCKADDR)&addr, sizeof(addr)))
					{

					}

比如我知道控制卡的固定端口是120，那addr.sin_port = htons(120); 而且szIpAddress就是我要填入的广播内容吗， 但是__CLEANUP__ 未定义，需要声明哪个？

[huangpan_123]

SOCKADDR_IN addr = {0}; SOCKET sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP); if(INVALID_SOCKET == sock) { WSACleanup(); //goto __CLEANUP__; } addr.sin_family = AF_INET; addr.sin_addr.S_un.S_addr = htonl(INADDR_BROADCAST); addr.sin_port = htons(120); BOOL bBroadcast = TRUE; if(SOCKET_ERROR == setsockopt(sock, SOL_SOCKET, SO_BROADCAST, (char*)&bBroadcast, sizeof(bBroadcast))) { WSACleanup(); //goto __CLEANUP__; } if(SOCKET_ERROR == sendto(sock, (char*)"EASYNET", sizeof("EASYNET"), 0, (LPSOCKADDR)&addr, sizeof(addr))) { // } 但是 link怎么设置啊： LEDDemTestDlg.obj : error LNK2001: unresolved external symbol __imp__sendto@24 LEDDemTestDlg.obj : error LNK2001: unresolved external symbol __imp__setsockopt@20 LEDDemTestDlg.obj : error LNK2001: unresolved external symbol __imp__htons@4 LEDDemTestDlg.obj : error LNK2001: unresolved external symbol __imp__htonl@4 LEDDemTestDlg.obj : error LNK2001: unresolved external symbol __imp__WSACleanup@0 LEDDemTestDlg.obj : error LNK2001: unresolved external symbol __imp__socket@12