將UDP消息廣播到所有可用的網卡

Question

我需要發送UDP消息到特定的IP和端口。

由於有3個網卡，

10.1.x.x 
10.2.x.x 
10.4.x.x 

當我發送一個UDP消息，我只在一個網絡適配器接收的消息......在IP的其餘部分都沒有收到。

我想在發送消息時檢查網絡適配器。我怎樣才能做到這一點？

---

目前我使用如下：

IPEndPoint localEndPoint = new IPEndPoint(IPAddress.Parse(LocalIP), 0); 
IPEndPoint targetEndPoint = new IPEndPoint(TargetIP, iTargetPort); 
UdpClient sendUdpClient = new UdpClient(localEndPoint); 
int numBytesSent = sendUdpClient.Send(CombineHeaderBody, CombineHeaderBody.Length, targetEndPoint); 

Answer 1

這實際上比聽起來更復雜，因爲如果你有多個接口，廣播不會總是出現在所有的接口上。爲了解決這個問題，我創建了這個類。

public class MyUdpClient : UdpClient 
{ 
    public MyUdpClient() : base() 
    { 
     //Calls the protected Client property belonging to the UdpClient base class. 
     Socket s = this.Client; 
     //Uses the Socket returned by Client to set an option that is not available using UdpClient. 
     s.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.Broadcast, 1); 
     s.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.DontRoute, 1); 
    } 

    public MyUdpClient(IPEndPoint ipLocalEndPoint) : base(ipLocalEndPoint) 
    { 
     //Calls the protected Client property belonging to the UdpClient base class. 
     Socket s = this.Client; 
     //Uses the Socket returned by Client to set an option that is not available using UdpClient. 
     s.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.Broadcast, 1); 
     s.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.DontRoute, 1); 
    } 

} 

然後通過廣播發送UDP數據包，我使用類似下面的內容。我正在使用IPAddress.Broadcast和MyUdpClient，這與您的代碼不同。

IPEndPoint localEndPoint = new IPEndPoint(IPAddress.Parse(LocalIP), 0); 
IPEndPoint targetEndPoint = new IPEndPoint(IPAddress.Broadcast, iTargetPort); 
MyUdpClient sendUdpClient = new MyUdpClient(localEndPoint); 
int numBytesSent = sendUdpClient.Send(CombineHeaderBody, CombineHeaderBody.Length, targetEndPoint); 

此外，你應該注意，當您使用特定ipaddress代替廣播的路由表只發送它的地址相匹配的接口。

所以在你的例子中，使用單播。您需要將LocalIP設置爲您要發送到的本地接口的IP。有三個接口，你將有三個本地IP，你需要選擇正確的一個使用。

IPEndPoint localEndPoint = new IPEndPoint(IPAddress.Parse(LocalIP), 0); 
IPEndPoint targetEndPoint = new IPEndPoint(TargetIP, iTargetPort); 
MyUdpClient sendUdpClient = new MyUdpClient(localEndPoint); 
int numBytesSent = sendUdpClient.Send(CombineHeaderBody, CombineHeaderBody.Length, targetEndPoint); 

由於路由被關閉，您可能會在所有接口上看到它，但您需要測試這個單播情況。

如果您不關心發送IP或端口，您可以使用以下代碼。

IPEndPoint targetEndPoint = new IPEndPoint(TargetIP, iTargetPort); 
MyUdpClient sendUdpClient = new MyUdpClient(); 
int numBytesSent = sendUdpClient.Send(CombineHeaderBody, CombineHeaderBody.Length, targetEndPoint); 

或廣播

IPEndPoint targetEndPoint = new IPEndPoint(IPAddress.Broadcast, iTargetPort); 
MyUdpClient sendUdpClient = new MyUdpClient(); 
int numBytesSent = sendUdpClient.Send(CombineHeaderBody, CombineHeaderBody.Length, targetEndPoint); 

與IPAddress.Broadcast的問題是，他們不會通過任何網關路由。爲了解決這個問題，你可以創建一個IPAddresses的列表，然後循環併發送。此外，由於發送可能會失敗，您無法控制的網絡問題，您應該也有一個try/catch塊。

ArrayList ip_addr_acq = new ArrayList(); 

ip_addr_acq.Add(IPAddress.Parse("10.1.1.1")); // add to list of address to send to 

try 
{ 
    foreach (IPAddress curAdd in ip_addr_acq) 
    { 
     IPEndPoint targetEndPoint = new IPEndPoint(curAdd , iTargetPort); 
     MyUdpClient sendUdpClient = new MyUdpClient(); 
     int numBytesSent = sendUdpClient.Send(CombineHeaderBody, CombineHeaderBody.Length, targetEndPoint); 

     Thread.Sleep(40); //small delay between each message 
    } 
} 
catch 
{ 
// handle any exceptions 
} 

編輯：見上述變化具有多個接口的單播，也Problem Trying to unicast packets to available networks.

Answer 2

如果發送到特定的IP地址，然後你是單播，不廣播。

Answer 3

擴展雷克斯的答案。這使您不必硬編碼您想要廣播的IP地址。循環遍歷所有接口，檢查它們是否已啓動，確保它具有IPv4信息，並且IPv4地址與其關聯。只需將「數據」變量更改爲想要廣播的任何數據，並將「目標」端口更改爲所需的數據。小缺點是，如果一個接口有多個與之關聯的IP地址，它將從每個地址廣播出去。注意：這也將嘗試通過任何VPN適配器發送廣播（通過網絡和共享中心/網絡連接，Win 7+驗證），並且如果您想接收響應，則必須保存所有客戶端。你也不需要輔助班。

foreach(NetworkInterface ni in NetworkInterface.GetAllNetworkInterfaces()) { 
     if(ni.OperationalStatus == OperationalStatus.Up && ni.SupportsMulticast && ni.GetIPProperties().GetIPv4Properties() != null) { 
      int id = ni.GetIPProperties().GetIPv4Properties().Index; 
      if(NetworkInterface.LoopbackInterfaceIndex != id) { 
       foreach(UnicastIPAddressInformation uip in ni.GetIPProperties().UnicastAddresses) { 
        if(uip.Address.AddressFamily == AddressFamily.InterNetwork) { 
         IPEndPoint local = new IPEndPoint(uip.Address.Address, 0); 
         UdpClient udpc = new UdpClient(local); 
         udpc.Client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.Broadcast, 1); 
         udpc.Client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.DontRoute, 1); 
         byte[] data = new byte[10]{1,2,3,4,5,6,7,8,9,10}; 
         IPEndPoint target = new IPEndPoint(IPAddress.Broadcast, 48888); 
         udpc.Send(data,data.Length, target); 
        } 
       } 
      } 
     } 
    } 

Answer 4

我通過（使用綁定）從每個適配器發送UDP廣播解決了這個問題：

public static void SNCT_SendBroadcast(out List<MyDevice> DevicesList) 
{ 
DevicesList = new List<MyDevice>(); 
byte[] data = new byte[2]; //broadcast data 
data[0] = 0x0A; 
data[1] = 0x60; 

IPEndPoint ip = new IPEndPoint(IPAddress.Broadcast, 45000); //braodcast IP address, and corresponding port 

NetworkInterface[] nics = System.Net.NetworkInformation.NetworkInterface.GetAllNetworkInterfaces(); //get all network interfaces of the computer 

foreach (NetworkInterface adapter in nics) 
{ 
// Only select interfaces that are Ethernet type and support IPv4 (important to minimize waiting time) 
if (adapter.NetworkInterfaceType != NetworkInterfaceType.Ethernet) { continue; } 
if (adapter.Supports(NetworkInterfaceComponent.IPv4) == false) { continue; } 
try 
{ 
    IPInterfaceProperties adapterProperties = adapter.GetIPProperties();  
    foreach (var ua in adapterProperties.UnicastAddresses) 
    { 
     if (ua.Address.AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork) 
     { 
     //SEND BROADCAST IN THE ADAPTER 
      //1) Set the socket as UDP Client 
      Socket bcSocket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp); //broadcast socket 
      //2) Set socker options 
      bcSocket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.Broadcast, 1); 
      bcSocket.ReceiveTimeout = 200; //receive timout 200ms 
      //3) Bind to the current selected adapter 
      IPEndPoint myLocalEndPoint = new IPEndPoint(ua.Address, 45000); 
      bcSocket.Bind(myLocalEndPoint); 
      //4) Send the broadcast data 
      bcSocket.SendTo(data, ip); 

     //RECEIVE BROADCAST IN THE ADAPTER 
      int BUFFER_SIZE_ANSWER = 1024; 
      byte[] bufferAnswer = new byte[BUFFER_SIZE_ANSWER]; 
      do 
      { 
       try 
       { 
        bcSocket.Receive(bufferAnswer); 
        DevicesList.Add(GetMyDevice(bufferAnswer)); //Corresponding functions to get the devices information. Depends on the application. 
       } 
       catch { break; } 

      } while (bcSocket.ReceiveTimeout != 0); //fixed receive timeout for each adapter that supports our broadcast 
      bcSocket.Close(); 
     } 
    } 
    } 
    catch { } 
} 
return; 
}