用MFC编的程序：发送广播只能在本机接收，在同局域网内的机器收不到

[tsair]

如题：本人程序要实现的功能是广播自己的主机名和ip地址（UDP广播）
问题：可以在本机收到广播，但是其他的机器收不到，盼解
代码如下：
CUdpDlg::CUdpDlg(CWnd* pParent /*=NULL*/)
: CDialog(CUdpDlg::IDD, pParent)
{
//{{AFX_DATA_INIT(CUdpDlg)
m_ip = _T("192.168.1.255");
m_sendport = 6000;
m_lsnport = 6000;//IP address for broadcasting , send port and listen port
//}}AFX_DATA_INIT
// Note that LoadIcon does not require a subsequent DestroyIcon in Win32
m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);
}


BOOL CUdpDlg::OnInitDialog()
{
CDialog::OnInitDialog();

// Add "About..." menu item to system menu.

// IDM_ABOUTBOX must be in the system command range.
ASSERT((IDM_ABOUTBOX & 0xFFF0) == IDM_ABOUTBOX);
ASSERT(IDM_ABOUTBOX < 0xF000);

CMenu* pSysMenu = GetSystemMenu(FALSE);
if (pSysMenu != NULL)
{
CString strAboutMenu;
strAboutMenu.LoadString(IDS_ABOUTBOX);
if (!strAboutMenu.IsEmpty())
{
pSysMenu->AppendMenu(MF_SEPARATOR);
pSysMenu->AppendMenu(MF_STRING, IDM_ABOUTBOX, strAboutMenu);
}
}

// Set the icon for this dialog. The framework does this automatically
// when the application's main window is not a dialog
SetIcon(m_hIcon, TRUE); // Set big icon
SetIcon(m_hIcon, FALSE); // Set small icon

// TODO: Add extra initialization here

UpdateData();
if (!m_socket.Create(0,SOCK_DGRAM))
{
AfxMessageBox("初始发送化套结字失败");
exit(0);
}

UpdateData();
if (!m_rsocket.Create(m_lsnport,SOCK_DGRAM))
{
AfxMessageBox("初始化监听套结字失败");
exit(0);
}
Buffer=GetLocalHost();
///////////////////////////////////////////

//AfxMessageBox(Buffer1);
//Buffer="I love you!";
//Buffer=GetLocalHost();
AfxMessageBox(Buffer);
////////////////////////////////////////////

return TRUE; // return TRUE unless you set the focus to a control
}

void CUdpDlg::OnSysCommand(UINT nID, LPARAM lParam)
{
if ((nID & 0xFFF0) == IDM_ABOUTBOX)
{
CAboutDlg dlgAbout;
dlgAbout.DoModal();
}
else
{
CDialog::OnSysCommand(nID, lParam);
}
}

// If you add a minimize button to your dialog, you will need the code below
// to draw the icon. For MFC applications using the document/view model,
// this is automatically done for you by the framework.

void CUdpDlg::OnPaint()
{
if (IsIconic())
{
CPaintDC dc(this); // device context for painting

SendMessage(WM_ICONERASEBKGND, (WPARAM) dc.GetSafeHdc(), 0);

// Center icon in client rectangle
int cxIcon = GetSystemMetrics(SM_CXICON);
int cyIcon = GetSystemMetrics(SM_CYICON);
CRect rect;
GetClientRect(&rect);
int x = (rect.Width() - cxIcon + 1) / 2;
int y = (rect.Height() - cyIcon + 1) / 2;

// Draw the icon
dc.DrawIcon(x, y, m_hIcon);
}
else
{
CDialog::OnPaint();
}
}

// The system calls this to obtain the cursor to display while the user drags
// the minimized window.
HCURSOR CUdpDlg::OnQueryDragIcon()
{
return (HCURSOR) m_hIcon;
}

#define RECV_BUF_LEN 100
void CUdpDlg::MsgRecv(){
CString recvip="";
UINT recvport ;
char RecvBuf[RECV_BUF_LEN];
CString showmsg;
// AfxMessageBox("就差一点点");
m_rsocket.ReceiveFrom(RecvBuf,RECV_BUF_LEN,recvip,recvport);
showmsg.Format("%s\r\n 发送端IP:%s 端口:%d\r\n",RecvBuf,recvip,recvport);
SetDlgItemText(IDC_SHOW,showmsg);
}

/*
*Click the send button to send localhost information
*/
void CUdpDlg::OnButtonSend()
{
UpdateData();
CString SendBuf;
SendBuf=Buffer;
//GetDlgItemText(IDC_EDITSEND,SendBuf);
m_socket.SendTo(SendBuf,SendBuf.GetLength()+1,m_sendport,m_ip);
SetDlgItemText(IDC_EDITSEND,"");
}

/*
*Get the ip address and hostname of localhost
*/
CString CUdpDlg::GetLocalHost()
{
//CString Buff;
char LocalHostName[50];
gethostname(LocalHostName,sizeof(LocalHostName));
//AfxMessageBox(LocalHostName);
hostent* hn;
hn=gethostbyname(LocalHostName);
CString Buffer1=inet_ntoa(*(struct in_addr *)hn->h_addr_list[0]);
CString Buffer2=Buffer1+" "+CString(LocalHostName);
//Buffer1=CString(LocalHostName);
//Buffer=GetLocalHost();
//AfxMessageBox(Buffer1);
//Buffer="I love you!";
//Buff=;
//return strIpAddr;
return Buffer2;
}

[tsair]

自己先顶了。。。。。

[猫已经找不回了]

up过

[tsair]

那位帅哥指点一下，这个程序就折腾了半天

[tsair]

在线等了。。。

[tsair]

高手周末都休息啊？

[zhangziliang04]

m_socket.SendTo(SendBuf,SendBuf.GetLength()+1,m_sendport,m_ip);
你在发送的时候，已经设定了广播的范围，是你自己的IP，所以其他机器收不到。你应该把m_ip指定为INADDR_BROADCAST。

[wjkkal]

CUdpDlg::CUdpDlg(CWnd* pParent /*=NULL*/) 
: CDialog(CUdpDlg::IDD, pParent) 
{ 
//{{AFX_DATA_INIT(CUdpDlg) 
m_ip = _T("192.168.1.255"); 
m_sendport = 6000; 
m_lsnport = 6000;//IP address for broadcasting , send port and listen port 
//}}AFX_DATA_INIT 
// Note that LoadIcon does not require a subsequent DestroyIcon in Win32 
m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME); 
} 


BOOL CUdpDlg::OnInitDialog() 
{ 
CDialog::OnInitDialog(); 

// Add "About..." menu item to system menu. 

// IDM_ABOUTBOX must be in the system command range. 
ASSERT((IDM_ABOUTBOX & 0xFFF0) == IDM_ABOUTBOX); 
ASSERT(IDM_ABOUTBOX < 0xF000); 

CMenu* pSysMenu = GetSystemMenu(FALSE); 
if (pSysMenu != NULL) 
{ 
CString strAboutMenu; 
strAboutMenu.LoadString(IDS_ABOUTBOX); 
if (!strAboutMenu.IsEmpty()) 
{ 
pSysMenu->AppendMenu(MF_SEPARATOR); 
pSysMenu->AppendMenu(MF_STRING, IDM_ABOUTBOX, strAboutMenu); 
} 
} 

// Set the icon for this dialog.  The framework does this automatically 
//  when the application's main window is not a dialog 
SetIcon(m_hIcon, TRUE); // Set big icon 
SetIcon(m_hIcon, FALSE); // Set small icon 

// TODO: Add extra initialization here 

UpdateData(); 
if (!m_socket.Create(0,SOCK_DGRAM)) 
{ 
AfxMessageBox("初始发送化套结字失败"); 
exit(0); 
} 

UpdateData(); 
if (!m_rsocket.Create(m_lsnport,SOCK_DGRAM)) 
{ 
AfxMessageBox("初始化监听套结字失败"); 
exit(0); 
} 
Buffer=GetLocalHost(); 
/////////////////////////////////////////// 

//AfxMessageBox(Buffer1); 
//Buffer="I love you!"; 
//Buffer=GetLocalHost(); 
AfxMessageBox(Buffer); 
//////////////////////////////////////////// 

return TRUE;  // return TRUE  unless you set the focus to a control 
} 

void CUdpDlg::OnSysCommand(UINT nID, LPARAM lParam) 
{ 
if ((nID & 0xFFF0) == IDM_ABOUTBOX) 
{ 
CAboutDlg dlgAbout; 
dlgAbout.DoModal(); 
} 
else 
{ 
CDialog::OnSysCommand(nID, lParam); 
} 
} 

// If you add a minimize button to your dialog, you will need the code below 
//  to draw the icon.  For MFC applications using the document/view model, 
//  this is automatically done for you by the framework. 

void CUdpDlg::OnPaint() 
{ 
if (IsIconic()) 
{ 
CPaintDC dc(this); // device context for painting 

SendMessage(WM_ICONERASEBKGND, (WPARAM) dc.GetSafeHdc(), 0); 

// Center icon in client rectangle 
int cxIcon = GetSystemMetrics(SM_CXICON); 
int cyIcon = GetSystemMetrics(SM_CYICON); 
CRect rect; 
GetClientRect(&rect); 
int x = (rect.Width() - cxIcon + 1) / 2; 
int y = (rect.Height() - cyIcon + 1) / 2; 

// Draw the icon 
dc.DrawIcon(x, y, m_hIcon); 
} 
else 
{ 
CDialog::OnPaint(); 
} 
} 

// The system calls this to obtain the cursor to display while the user drags 
//  the minimized window. 
HCURSOR CUdpDlg::OnQueryDragIcon() 
{ 
return (HCURSOR) m_hIcon; 
} 

#define RECV_BUF_LEN 100 
void CUdpDlg::MsgRecv(){ 
CString recvip=""; 
UINT recvport ; 
char RecvBuf[RECV_BUF_LEN]; 
CString showmsg; 
// AfxMessageBox("就差一点点"); 
m_rsocket.ReceiveFrom(RecvBuf,RECV_BUF_LEN,recvip,recvport); 
showmsg.Format("%s\r\n 发送端IP:%s 端口:%d\r\n",RecvBuf,recvip,recvport); 
SetDlgItemText(IDC_SHOW,showmsg); 
} 

/* 
*Click the send button to send localhost information 
*/ 
void CUdpDlg::OnButtonSend() 
{ 
UpdateData(); 
CString SendBuf; 
SendBuf=Buffer; 
//GetDlgItemText(IDC_EDITSEND,SendBuf); 
m_socket.SendTo(SendBuf,SendBuf.GetLength()+1,m_sendport,m_ip); 
SetDlgItemText(IDC_EDITSEND,""); 
} 

/* 
*Get the ip address and hostname of localhost 
*/ 
CString CUdpDlg::GetLocalHost() 
{ 
//CString Buff; 
char LocalHostName[50]; 
gethostname(LocalHostName,sizeof(LocalHostName)); 
//AfxMessageBox(LocalHostName); 
hostent* hn; 
hn=gethostbyname(LocalHostName); 
CString Buffer1=inet_ntoa(*(struct in_addr *)hn->h_addr_list[0]); 
CString Buffer2=Buffer1+" "+CString(LocalHostName); 
//Buffer1=CString(LocalHostName); 
//Buffer=GetLocalHost(); 
//AfxMessageBox(Buffer1); 
//Buffer="I love you!"; 
//Buff=; 
//return strIpAddr; 
return Buffer2; 
}