我需要向特定的 IP 和端口发送 UDP 消息。
由于有3个网卡，
10.1.x.x
10.2.x.x
10.4.x.x
当我发送 UDP 消息时，我只在一个网络适配器中接收消息……其余的 ip 没有接收。
我想在发送消息时检查网络适配器。我怎样才能做到这一点？
目前我正在使用以下内容：
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);
这实际上比听起来更棘手，因为如果您有多个接口，则广播不会总是发送到所有接口。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);
}
}
然后通过广播发送 UDP 数据包，我使用如下内容。我正在使用IPAddress.Broadcastand MyUdpClient，这与您的代码不同。
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);
此外，您应该注意，当您使用特定ipaddress而不是广播时，路由表只会将其发送到与地址匹配的接口。
因此，在您的示例中，使用了单播。您需要设置LocalIP为要发送到的本地接口的 IP。使用三个接口，您将拥有三个本地 IP，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);
因为路由已关闭，您可能会在所有接口上看到它，但您需要针对单播情况进行测试。
如果您不关心发送 IP 或端口，您可以使用以下代码。
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);
问题IPAddress.Broadcast在于它们不会通过任何网关进行路由。为了解决这个问题，您可以创建一个列表，IPAddresses然后循环并发送。此外，由于发送可能因您无法控制的网络问题而失败，因此您还应该有一个 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：请参阅上面对具有多个接口的单播的更改以及尝试将数据包单播到可用网络的问题。
我通过从每个适配器发送 UDP 广播（使用绑定）解决了这个问题：
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;
}
扩展雷克斯的答案。这使您不必对要广播的 IP 地址进行硬编码。循环遍历所有接口，检查它们是否启动，确保它具有 IPv4 信息，并且 IPv4 地址与之关联。只需将“数据”变量更改为您想要广播的任何数据，并将“目标”端口更改为您想要的。一个小缺点是，如果一个接口有多个与之关联的 IP 地址，它将从每个地址广播出去。注意：这也将尝试通过任何 VPN 适配器发送广播（通过网络和共享中心/网络连接，已验证 Win 7+），如果您想接收响应，则必须保存所有客户端。您也不需要中学课程。
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);
}
}
}
}
}
如果您要发送到特定的 IP 地址，那么您是单播，而不是广播。