您可知道如何通过`HTTP2`实现TCP的内网穿透？？？

可能有人很疑惑应用层转发传输层？，为什么会有这样的需求啊？？？哈哈技术无所不用其极，由于一些场景下，对于一个服务器存在某一个内部网站中，但是对于这个服务器它没有访问外网的权限，虽然也可以申请端口访问外部指定的ip+端口，但是对于访问服务内部的TCP的时候我们就会发现忘记申请了！这个时候我们又要提交申请，又要等审批，然后开通端口，对于这个步骤不是一般的麻烦，所以我在想是否可以直接利用现有的Http网关的端口进行转发内部的TCP服务？这个时候我询问了我们的老九大佬，由于我之前也做过通过H2实现HTTP内网穿透，可以利用H2将内部网络中的服务映射出来，但是由于底层是基于yarp的一些方法实现，所以并没有考虑过TCP，然后于老九大佬交流深究，决定尝试验证可行性，然后我们的Taibai项目就诞生了，为什么叫Taibai？您仔细看看这个拼音，翻译过来就是太白，确实全称应该叫太白金星，寓意上天遁地无所不能！下面我们介绍一下具体实现逻辑，确实您仔细看会发现实现是真的超级简单的！

创建Core项目用于共用的核心类库

创建项目名Taibai.Core

下面几个方法都是用于操作Stream的类

DelegatingStream.cs

namespace Taibai.Core; /// <summary> /// 委托流 /// </summary> public abstract class DelegatingStream : Stream { /// <summary> /// 获取所包装的流对象 /// </summary> protected readonly Stream Inner; /// <summary> /// 委托流 /// </summary> /// <param name="inner"></param> public DelegatingStream(Stream inner) { this.Inner = inner; } /// <inheritdoc/> public override bool CanRead => Inner.CanRead; /// <inheritdoc/> public override bool CanSeek => Inner.CanSeek; /// <inheritdoc/> public override bool CanWrite => Inner.CanWrite; /// <inheritdoc/> public override long Length => Inner.Length; /// <inheritdoc/> public override bool CanTimeout => Inner.CanTimeout; /// <inheritdoc/> public override int ReadTimeout { get => Inner.ReadTimeout; set => Inner.ReadTimeout = value; } /// <inheritdoc/> public override int WriteTimeout { get => Inner.WriteTimeout; set => Inner.WriteTimeout = value; } /// <inheritdoc/> public override long Position { get => Inner.Position; set => Inner.Position = value; } /// <inheritdoc/> public override void Flush() { Inner.Flush(); } /// <inheritdoc/> public override Task FlushAsync(CancellationToken cancellationToken) { return Inner.FlushAsync(cancellationToken); } /// <inheritdoc/> public override int Read(byte[] buffer, int offset, int count) { return Inner.Read(buffer, offset, count); } /// <inheritdoc/> public override int Read(Span<byte> destination) { return Inner.Read(destination); } /// <inheritdoc/> public override Task<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken) { return Inner.ReadAsync(buffer, offset, count, cancellationToken); } /// <inheritdoc/> public override ValueTask<int> ReadAsync(Memory<byte> destination, CancellationToken cancellationToken = default) { return Inner.ReadAsync(destination, cancellationToken); } /// <inheritdoc/> public override long Seek(long offset, SeekOrigin origin) { return Inner.Seek(offset, origin); } /// <inheritdoc/> public override void SetLength(long value) { Inner.SetLength(value); } /// <inheritdoc/> public override void Write(byte[] buffer, int offset, int count) { Inner.Write(buffer, offset, count); } /// <inheritdoc/> public override void Write(ReadOnlySpan<byte> source) { Inner.Write(source); } /// <inheritdoc/> public override Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken) { return Inner.WriteAsync(buffer, offset, count, cancellationToken); } /// <inheritdoc/> public override ValueTask WriteAsync(ReadOnlyMemory<byte> source, CancellationToken cancellationToken = default) { return Inner.WriteAsync(source, cancellationToken); } /// <inheritdoc/> public override IAsyncResult BeginRead(byte[] buffer, int offset, int count, AsyncCallback? callback, object? state) { return TaskToAsyncResult.Begin(ReadAsync(buffer, offset, count), callback, state); } /// <inheritdoc/> public override int EndRead(IAsyncResult asyncResult) { return TaskToAsyncResult.End<int>(asyncResult); } /// <inheritdoc/> public override IAsyncResult BeginWrite(byte[] buffer, int offset, int count, AsyncCallback? callback, object? state) { return TaskToAsyncResult.Begin(WriteAsync(buffer, offset, count), callback, state); } /// <inheritdoc/> public override void EndWrite(IAsyncResult asyncResult) { TaskToAsyncResult.End(asyncResult); } /// <inheritdoc/> public override int ReadByte() { return Inner.ReadByte(); } /// <inheritdoc/> public override void WriteByte(byte value) { Inner.WriteByte(value); } /// <inheritdoc/> public sealed override void Close() { base.Close(); } }

SafeWriteStream.cs

public class SafeWriteStream(Stream inner) : DelegatingStream(inner) { private readonly SemaphoreSlim semaphoreSlim = new(1, 1); public override async ValueTask WriteAsync(ReadOnlyMemory<byte> source, CancellationToken cancellationToken = default) { try { await this.semaphoreSlim.WaitAsync(CancellationToken.None); await base.WriteAsync(source, cancellationToken); await this.FlushAsync(cancellationToken); } finally { this.semaphoreSlim.Release(); } } public override ValueTask DisposeAsync() { this.semaphoreSlim.Dispose(); return this.Inner.DisposeAsync(); } protected override void Dispose(bool disposing) { this.semaphoreSlim.Dispose(); this.Inner.Dispose(); } }

创建服务端

创建一个WebAPI的项目项目名Taibai.Server并且依赖Taibai.Core项目

创建ServerService.cs，这个类是用于管理内网的客户端的，这个一般是部署在内网服务器上，用于将内网的端口映射出来，但是我们的Demo只实现了简单的管理不做端口的管理。

using System.Collections.Concurrent; using Microsoft.AspNetCore.Http.Features; using Microsoft.AspNetCore.Http.Timeouts; using Taibai.Core; namespace Taibai.Server; public static class ServerService { private static readonly ConcurrentDictionary<string, (CancellationToken, Stream)> ClusterConnections = new(); public static async Task StartAsync(HttpContext context) { // 如果不是http2协议，我们不处理, 因为我们只支持http2 if (context.Request.Protocol != HttpProtocol.Http2) { return; } // 获取query var query = context.Request.Query; // 我们需要强制要求name参数 var name = query["name"]; if (string.IsNullOrEmpty(name)) { context.Response.StatusCode = 400; Console.WriteLine("Name is required"); return; } Console.WriteLine("Accepted connection from " + name); // 获取http2特性 var http2Feature = context.Features.Get<IHttpExtendedConnectFeature>(); // 禁用超时 context.Features.Get<IHttpRequestTimeoutFeature>()?.DisableTimeout(); // 得到双工流 var stream = new SafeWriteStream(await http2Feature.AcceptAsync()); // 将其添加到集合中，以便我们可以在其他地方使用 CreateConnectionChannel(name, context.RequestAborted, stream); // 注册取消连接 context.RequestAborted.Register(() => { // 当取消时，我们需要从集合中删除 ClusterConnections.TryRemove(name, out _); }); // 由于我们需要保持连接，所以我们需要等待，直到客户端主动断开连接。 await Task.Delay(-1, context.RequestAborted); } /// <summary> /// 通过名称获取连接 /// </summary> /// <param name="host"></param> /// <returns></returns> public static (CancellationToken, Stream) GetConnectionChannel(string host) { return ClusterConnections[host]; } /// <summary> /// 注册连接 /// </summary> /// <param name="host"></param> /// <param name="cancellationToken"></param> /// <param name="stream"></param> public static void CreateConnectionChannel(string host, CancellationToken cancellationToken, Stream stream) { ClusterConnections.GetOrAdd(host, _ => (cancellationToken, stream)); } }

然后再创建ClientMiddleware.cs，并且继承IMiddleware，这个是我们本地使用的客户端链接的时候进入的中间件，再这个中间件会获取query中携带的name去找到指定的Stream，然后会将客户端的Stream和获取的server的Stream进行Copy，在这里他们会将读取的数据写入到对方的流中，这样就实现了双工通信

using Microsoft.AspNetCore.Http.Features; using Microsoft.AspNetCore.Http.Timeouts; using Taibai.Core; namespace Taibai.Server; public class ClientMiddleware : IMiddleware { public async Task InvokeAsync(HttpContext context, RequestDelegate next) { // 如果不是http2协议，我们不处理, 因为我们只支持http2 if (context.Request.Protocol != HttpProtocol.Http2) { return; } var name = context.Request.Query["name"]; if (string.IsNullOrEmpty(name)) { context.Response.StatusCode = 400; Console.WriteLine("Name is required"); return; } Console.WriteLine("Accepted connection from " + name); var http2Feature = context.Features.Get<IHttpExtendedConnectFeature>(); context.Features.Get<IHttpRequestTimeoutFeature>()?.DisableTimeout(); // 得到双工流 var stream = new SafeWriteStream(await http2Feature.AcceptAsync()); // 通过name找到指定的server链接，然后进行转发。 var (cancellationToken, reader) = ServerService.GetConnectionChannel(name); try { // 注册取消连接 cancellationToken.Register(() => { Console.WriteLine("断开连接"); stream.Close(); }); // 得到客户端的流，然后给我们的SafeWriteStream,然后我们就可以进行转发了 var socketStream = new SafeWriteStream(reader); // 在这里他们会将读取的数据写入到对方的流中，这样就实现了双工通信，这个非常简单并且性能也不错。 await Task.WhenAll( stream.CopyToAsync(socketStream, context.RequestAborted), socketStream.CopyToAsync(stream, context.RequestAborted) ); } catch (Exception e) { Console.WriteLine("断开连接" + e.Message); throw; } } }

打开Program.cs

using Taibai.Server; var builder = WebApplication.CreateBuilder(new WebApplicationOptions()); builder.Host.ConfigureHostOptions(host => { host.ShutdownTimeout = TimeSpan.FromSeconds(1d); }); builder.Services.AddSingleton<ClientMiddleware>(); var app = builder.Build(); app.Map("/server", app => { app.Use(Middleware); static async Task Middleware(HttpContext context, RequestDelegate _) { await ServerService.StartAsync(context); } }); app.Map("/client", app => { app.UseMiddleware<ClientMiddleware>(); }); app.Run();

在这里我们将server的所有路由都交过ServerService.StartAsync接管，再server会请求这个地址，

而/client则给了ClientMiddleware中间件。

创建客户端

上面我们实现了服务端，其实服务端可以完全放置到现有的WebApi项目当中的，而且代码也不是很多。

客户端我们创建一个控制台项目名：Taibai.Client，并且依赖Taibai.Core项目

由于我们的客户端有些特殊，再server中部署的它不需要监听端口，它只需要将服务器的数据转发到指定的一个地址即可，所以我们需要将客户端的server部署的和本地部署的分开实现，再服务器部署的客户端我们命名为MonitorClient.cs

ClientOption.cs用于传递我们的客户端地址配置

public class ClientOption { /// <summary> /// 服务地址 /// </summary> public string ServiceUri { get; set; } }

MonitorClient.cs，作为服务器的转发客户端。

using System.Net; using System.Net.Security; using System.Net.Sockets; using Taibai.Core; namespace Taibai.Client; public class MonitorClient(ClientOption option) { private string Protocol = "taibai"; private readonly HttpMessageInvoker httpClient = new(CreateDefaultHttpHandler(), true); private readonly Socket socket = new(SocketType.Stream, ProtocolType.Tcp); private static SocketsHttpHandler CreateDefaultHttpHandler() { return new SocketsHttpHandler { // 允许多个http2连接 EnableMultipleHttp2Connections = true, // 设置连接超时时间 ConnectTimeout = TimeSpan.FromSeconds(60), SslOptions = new SslClientAuthenticationOptions { // 由于我们没有证书，所以我们需要设置为true RemoteCertificateValidationCallback = (_, _, _, _) => true, }, }; } public async Task TransportAsync(CancellationToken cancellationToken) { Console.WriteLine("链接中！"); // 由于是测试，我们就目前先写死远程地址 await socket.ConnectAsync(new IPEndPoint(IPAddress.Parse("192.168.31.250"), 3389), cancellationToken); Console.WriteLine("连接成功"); // 将Socket转换为流 var stream = new NetworkStream(socket); try { // 创建服务器的连接，然后返回一个流，这个是H2的流 var serverStream = await this.CreateServerConnectionAsync(cancellationToken); Console.WriteLine("链接服务器成功"); // 将两个流连接起来，这样我们就可以进行双工通信了。它们会自动进行数据的传输。 await Task.WhenAll( stream.CopyToAsync(serverStream, cancellationToken), serverStream.CopyToAsync(stream, cancellationToken) ); } catch (Exception ex) { Console.WriteLine(ex.Message); throw; } } /// <summary> /// 创建服务器的连接 /// </summary> /// <param name="cancellationToken"></param> /// <exception cref="OperationCanceledException"></exception> /// <returns></returns> public async Task<SafeWriteStream> CreateServerConnectionAsync(CancellationToken cancellationToken) { var stream = await Http20ConnectServerAsync(cancellationToken); return new SafeWriteStream(stream); } /// <summary> /// 创建http2连接 /// </summary> /// <param name="cancellationToken"></param> /// <returns></returns> private async Task<Stream> Http20ConnectServerAsync(CancellationToken cancellationToken) { var serverUri = new Uri(option.ServiceUri); // 这里我们使用Connect方法，因为我们需要建立一个双工流, 这样我们就可以进行双工通信了。 var request = new HttpRequestMessage(HttpMethod.Connect, serverUri); // 如果设置了Connect，那么我们需要设置Protocol request.Headers.Protocol = Protocol; // 我们需要设置http2的版本 request.Version = HttpVersion.Version20; // 我们需要确保我们的请求是http2的 request.VersionPolicy = HttpVersionPolicy.RequestVersionExact; // 设置一下超时时间，这样我们就可以在超时的时候取消连接了。 using var timeoutTokenSource = new CancellationTokenSource(TimeSpan.FromSeconds(60)); using var linkedTokenSource = CancellationTokenSource.CreateLinkedTokenSource(timeoutTokenSource.Token, cancellationToken); // 发送请求，然后等待响应 var httpResponse = await this.httpClient.SendAsync(request, linkedTokenSource.Token); // 返回h2的流，用于传输数据 return await httpResponse.Content.ReadAsStreamAsync(linkedTokenSource.Token); } }

创建我们的本地客户端实现类。

Client.cs这个就是在我们本地部署的服务，然后会监听本地的60112的端口，然后会吧这个端口的数据转发到我们的服务器，然后服务器会根据我们使用的name去找到指定的客户端进行交互传输。

using System.Net; using System.Net.Security; using System.Net.Sockets; using Taibai.Core; using HttpMethod = System.Net.Http.HttpMethod; namespace Taibai.Client; public class Client { private readonly ClientOption option; private string Protocol = "taibai"; private readonly HttpMessageInvoker httpClient; private readonly Socket socket; public Client(ClientOption option) { this.option = option; this.httpClient = new HttpMessageInvoker(CreateDefaultHttpHandler(), true); this.socket = new Socket(SocketType.Stream, ProtocolType.Tcp); // 监听本地端口 this.socket.Bind(new IPEndPoint(IPAddress.Loopback, 60112)); this.socket.Listen(10); } private static SocketsHttpHandler CreateDefaultHttpHandler() { return new SocketsHttpHandler { // 允许多个http2连接 EnableMultipleHttp2Connections = true, ConnectTimeout = TimeSpan.FromSeconds(60), ResponseDrainTimeout = TimeSpan.FromSeconds(60), SslOptions = new SslClientAuthenticationOptions { // 由于我们没有证书，所以我们需要设置为true RemoteCertificateValidationCallback = (sender, certificate, chain, sslPolicyErrors) => true, }, }; } public async Task TransportAsync(CancellationToken cancellationToken) { Console.WriteLine("Listening on 60112"); // 等待客户端连接 var client = await this.socket.AcceptAsync(cancellationToken); Console.WriteLine("Accepted connection from " + client.RemoteEndPoint); try { // 将Socket转换为流 var stream = new NetworkStream(client); // 创建服务器的连接,然后返回一个流, 这个是H2的流 var serverStream = await this.CreateServerConnectionAsync(cancellationToken); Console.WriteLine("Connected to server"); // 将两个流连接起来, 这样我们就可以进行双工通信了. 它们会自动进行数据的传输. await Task.WhenAll( stream.CopyToAsync(serverStream, cancellationToken), serverStream.CopyToAsync(stream, cancellationToken) ); } catch (Exception e) { Console.WriteLine(e); throw; } } /// <summary> /// 创建与服务器的连接 /// </summary> /// <param name="cancellationToken"></param> /// <exception cref="OperationCanceledException"></exception> /// <returns></returns> public async Task<SafeWriteStream> CreateServerConnectionAsync(CancellationToken cancellationToken) { var stream = await this.Http20ConnectServerAsync(cancellationToken); return new SafeWriteStream(stream); } private async Task<Stream> Http20ConnectServerAsync(CancellationToken cancellationToken) { var serverUri = new Uri(option.ServiceUri); // 这里我们使用Connect方法, 因为我们需要建立一个双工流 var request = new HttpRequestMessage(HttpMethod.Connect, serverUri); // 由于我们设置了Connect方法, 所以我们需要设置协议，这样服务器才能识别 request.Headers.Protocol = Protocol; // 设置http2版本 request.Version = HttpVersion.Version20; // 强制使用http2 request.VersionPolicy = HttpVersionPolicy.RequestVersionExact; using var timeoutTokenSource = new CancellationTokenSource(TimeSpan.FromSeconds(60)); using var linkedTokenSource = CancellationTokenSource.CreateLinkedTokenSource(timeoutTokenSource.Token, cancellationToken); // 发送请求，等待服务器验证。 var httpResponse = await this.httpClient.SendAsync(request, linkedTokenSource.Token); // 返回一个流 return await httpResponse.Content.ReadAsStreamAsync(linkedTokenSource.Token); } }

然后再Program.cs中，我们封装一个简单的控制台版本。

using Taibai.Client; const string commandTemplate = @" 当前是 Taibai 客户端，输入以下命令： - `help` 显示帮助 - `monitor` 使用监控模式，监听本地端口，将流量转发到服务端的指定地址 - `monitor=https://localhost:7153/server?name=test` 监听本地端口，将流量转发到服务端指定的客户端名称为 test 的地址 - `client` 使用客户端模式，连接服务端的指定地址，将流量转发到本地端口 - `client=https://localhost:7153/client?name=test` 连接服务端指定当前客户端名称为 test，将流量转发到本地端口 - `exit` 退出输入命令： "; while (true) { Console.WriteLine(commandTemplate); var command = Console.ReadLine(); if (command?.StartsWith("monitor=") == true) { var client = new MonitorClient(new ClientOption() { ServiceUri = command[8..] }); await client.TransportAsync(new CancellationToken()); } else if (command?.StartsWith("client=") == true) { var client = new Client(new ClientOption() { ServiceUri = command[7..] }); await client.TransportAsync(new CancellationToken()); } else if (command == "help") { Console.WriteLine(commandTemplate); } else if (command == "exit") { Console.WriteLine("Bye!"); break; } else { Console.WriteLine("未知命令"); } }

我们默认提供了命令去使用指定的一个模式去链接客户端，

然后我们发布一下Taibai.Client，发布完成以后我们使用ide启动我们的Taibai.Server，请注意我们需要使用HTTPS进行启动的，HTTP是不支持H2的！

然后再客户端中打开俩个控制台面板，一个作为监听的monitor，一个作为client进行链接到我们的服务器中。