我需要发送一个UDP消息到特定的IP和端口。
由于有三个网络卡，
10.1.x.x
10.2.x.x
10.4.x.x
我发送UDP消息时，只能在一个网络适配器中接收到消息...其他IP地址都无法接收。
我想在发送消息时检查网络适配器。我该如何做？
目前我正在使用以下方法：
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);
这实际上比听起来要困难，因为如果您有多个接口，则广播消息不会始终发送到所有接口。为了解决这个问题，我创建了这个类。
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);
}
}
我使用类似下面的代码来通过广播发送UDP数据包。我使用IPAddress.Broadcast和MyUdpClient，这与你的代码不同。
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);
ipaddress而不是广播时，路由表仅将其发送到与地址匹配的接口。因此，在您的示例中，使用单播。您需要将LocalIP设置为要发送到的本地接口的IP。有三个接口，您需要选择正确的一个来使用。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);
因为路由被关闭，你可能会在所有接口上看到它，但对于单播情况，你需要进行测试。
如果你不关心发送的IP或端口，你可以使用以下代码。
IPEndPoint targetEndPoint = new IPEndPoint(TargetIP, iTargetPort);
MyUdpClient sendUdpClient = new MyUdpClient();
int numBytesSent = sendUdpClient.Send(CombineHeaderBody, CombineHeaderBody.Length, targetEndPoint);
或用于广播
IPEndPoint targetEndPoint = new IPEndPoint(IPAddress.Broadcast, iTargetPort);
MyUdpClient sendUdpClient = new MyUdpClient();
int numBytesSent = sendUdpClient.Send(CombineHeaderBody, CombineHeaderBody.Length, targetEndPoint);
IPAddress.Broadcast存在的问题是它们不能通过任何网关路由。为了解决这个问题，您可以创建一个IPAddresses列表，然后循环发送。另外，由于发送可能会因网络问题而失败，而您无法控制此类问题，因此还应该添加try/catch块。
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
}
编辑：请参见上面更改为使用多个接口的单播，以及尝试向可用网络单播数据包时出现问题。
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;
}
Rex的回答的拓展。这使你不必硬编码你想要广播的IP地址。循环遍历所有接口，检查它们是否正常工作，确保它具有IPv4信息，并与之关联的是IPv4地址。只需将“data”变量更改为您想要广播的任何数据，将“target”端口更改为您想要的端口即可。小缺点是，如果一个接口有多个IP地址与其关联，它将从每个地址广播。注意：这也会尝试通过任何VPN适配器发送广播（通过网络和共享中心/网络连接，Win 7+验证），如果您想要接收响应，您将需要保存所有客户端。您也不需要第二个类。
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);
}
}
}
}
}
如果您发送到特定的IP地址，则是单播，而不是广播。