2019-10-30-C#-dotnet-core-局域网组播方法
Posted lindexi_gd
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title | author | date | CreateTime | categories |
---|---|---|---|---|
C# dotnet core 局域网组播方法 | lindexi | 2019-10-30 9:0:48 +0800 | 2019-10-29 12:2:46 +0800 | dotnet C# |
我在微软官网找到了用 C# 做 UDP 组播的方法,我优化一些逻辑,保留核心代码,然后加了一点封装
在使用之前需要注意的是组播可以用来做局域网传输,但是组播不是可靠的方案,随时可能因为路由器等发送失败或无法接收消息
使用组播的方法是创建 Socket 通过 UDP 向组播地址发送数据或从组播地址接收数据
可以作为组播的地址是 239.0.0.0~239.255.255.255 的范围,这个范围是局域网可用。但实际可用或不可用还需要靠实际的路由器
首先创建一个 Socket 然后绑定到端口
private IPAddress LocalIpAddress set; get; = IPAddress.Any; private Socket MulticastSocket get; private const int MulticastPort = 15003; private void TryBindSocket() for (var i = MulticastPort; i < 65530; i++) try EndPoint localEndPoint = new IPEndPoint(LocalIpAddress, i); MulticastSocket.Bind(localEndPoint); return; catch (SocketException e) Console.WriteLine(e);
绑定的端口是用来接收的端口,所以绑定失败不会影响发送
绑定完成需要加入组播网络
var multicastOption = new MulticastOption(MulticastAddress, IPAddress.Any); MulticastSocket.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.AddMembership, multicastOption); /// <summary> /// 组播地址 /// <para/> /// 224.0.0.0~224.0.0.255为预留的组播地址(永久组地址),地址224.0.0.0保留不做分配,其它地址供路由协议使用; /// <para/> /// 224.0.1.0~224.0.1.255是公用组播地址,可以用于Internet; /// <para/> /// 224.0.2.0~238.255.255.255为用户可用的组播地址(临时组地址),全网范围内有效; /// <para/> /// 239.0.0.0~239.255.255.255为本地管理组播地址,仅在特定的本地范围内有效。 /// </summary> public IPAddress MulticastAddress set; get;
需要注意,上面代码的 LocalIpAddress 写的是 Any 也就是只有在默认的网卡是和其他设备网段才能访问
如果发现其他设备不能接收到信息,那么请修改 LocalIpAddress 为你设备的地址
接收方法和接收其他相同
private void ReceiveBroadcastMessages() // 接收需要绑定 MulticastPort 端口 var bytes = new byte[MaxByteLength]; EndPoint remoteEndPoint = new IPEndPoint(IPAddress.Any, 0); try while (true) var length = MulticastSocket.ReceiveFrom(bytes, ref remoteEndPoint); Console.WriteLine(Encoding.UTF8.GetString(bytes, 0, length)); catch (Exception e) Console.WriteLine(e.ToString());
接收和发送都是二进制
/// <summary> /// 发送组播 /// </summary> /// <param name="message"></param> public void SendBroadcastMessage(string message) try var endPoint = new IPEndPoint(MulticastAddress, MulticastPort); var byteList = Encoding.UTF8.GetBytes(message); MulticastSocket.SendTo(byteList, endPoint); catch (Exception e) Console.WriteLine("\\n" + e);
所有代码
internal class PeerMulticastFinder : IDisposable /// <inheritdoc /> public PeerMulticastFinder() MulticastSocket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp); MulticastAddress = IPAddress.Parse("230.138.100.2"); /// <summary> /// 寻找局域网设备 /// </summary> public void FindPeer() // 实际是反过来,让其他设备询问 StartMulticast(); var ipList = GetLocalIpList().ToList(); var message = string.Join(';',ipList); SendBroadcastMessage(message); // 先发送再获取消息,这样就不会收到自己发送的消息 ReceivedMessage += (s, e) => Console.WriteLine($"找到 e"); ; /// <summary> /// 获取本地 IP 地址 /// </summary> /// <returns></returns> private IEnumerable<IPAddress> GetLocalIpList() var host = Dns.GetHostEntry(Dns.GetHostName()); foreach (var ip in host.AddressList) if (ip.AddressFamily == AddressFamily.InterNetwork) yield return ip; /// <summary> /// 组播地址 /// <para/> /// 224.0.0.0~224.0.0.255为预留的组播地址(永久组地址),地址224.0.0.0保留不做分配,其它地址供路由协议使用; /// <para/> /// 224.0.1.0~224.0.1.255是公用组播地址,可以用于Internet; /// <para/> /// 224.0.2.0~238.255.255.255为用户可用的组播地址(临时组地址),全网范围内有效; /// <para/> /// 239.0.0.0~239.255.255.255为本地管理组播地址,仅在特定的本地范围内有效。 /// </summary> public IPAddress MulticastAddress set; get; private const int MulticastPort = 15003; /// <summary> /// 启动组播 /// </summary> public void StartMulticast() try // 如果首次绑定失败,那么将无法接收,但是可以发送 TryBindSocket(); // Define a MulticastOption object specifying the multicast group // address and the local IPAddress. // The multicast group address is the same as the address used by the server. // 有多个 IP 时,指定本机的 IP 地址,此时可以接收到具体的内容 var multicastOption = new MulticastOption(MulticastAddress, IPAddress.Parse("172.18.134.16")); MulticastSocket.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.AddMembership, multicastOption); catch (Exception e) Console.WriteLine(e.ToString()); Task.Run(ReceiveBroadcastMessages); /// <summary> /// 收到消息 /// </summary> public event EventHandler<string> ReceivedMessage; private void ReceiveBroadcastMessages() // 接收需要绑定 MulticastPort 端口 var bytes = new byte[MaxByteLength]; EndPoint remoteEndPoint = new IPEndPoint(IPAddress.Any, 0); try while (!_disposedValue) var length = MulticastSocket.ReceiveFrom(bytes, ref remoteEndPoint); OnReceivedMessage(Encoding.UTF8.GetString(bytes, 0, length)); catch (Exception e) Console.WriteLine(e.ToString()); /// <summary> /// 发送组播 /// </summary> /// <param name="message"></param> public void SendBroadcastMessage(string message) try var endPoint = new IPEndPoint(MulticastAddress, MulticastPort); var byteList = Encoding.UTF8.GetBytes(message); if (byteList.Length > MaxByteLength) throw new ArgumentException($"传入 message 转换为 byte 数组长度太长,不能超过MaxByteLength字节") Data = "message", message , "byteList", byteList ; MulticastSocket.SendTo(byteList, endPoint); catch (Exception e) Console.WriteLine("\\n" + e); private IPAddress LocalIpAddress set; get; = IPAddress.Any; private Socket MulticastSocket get; private void TryBindSocket() for (var i = MulticastPort; i < 65530; i++) try EndPoint localEndPoint = new IPEndPoint(LocalIpAddress, i); MulticastSocket.Bind(localEndPoint); return; catch (SocketException e) Console.WriteLine(e); private const int MaxByteLength = 1024; #region IDisposable Support private bool _disposedValue = false; // 要检测冗余调用 private void Dispose(bool disposing) if (!_disposedValue) if (disposing) MulticastSocket.Dispose(); ReceivedMessage = null; MulticastAddress = null; _disposedValue = true; // 添加此代码以正确实现可处置模式。 public void Dispose() // 请勿更改此代码。将清理代码放入以上 Dispose(bool disposing) 中。 Dispose(true); GC.SuppressFinalize(this); #endregion private void OnReceivedMessage(string e) ReceivedMessage?.Invoke(this, e);
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