From 9da7f18b9d838db521a3230b4c9296cad5153854 Mon Sep 17 00:00:00 2001
From: xljiulang <366193849@qq.com>
Date: Fri, 13 Aug 2021 20:50:03 +0800
Subject: [PATCH] =?UTF-8?q?github=20ssh=E8=BD=AC=E5=8F=91=E5=8A=9F?=
 =?UTF-8?q?=E8=83=BD?=
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Content-Transfer-Encoding: 8bit

---
 FastGithub.ReverseProxy/GitubSshHandler.cs    | 136 ++++++++++++++++++
 .../KestrelServerOptionsExtensions.cs         |  25 ++++
 FastGithub/Program.cs                         |   1 +
 3 files changed, 162 insertions(+)
 create mode 100644 FastGithub.ReverseProxy/GitubSshHandler.cs

diff --git a/FastGithub.ReverseProxy/GitubSshHandler.cs b/FastGithub.ReverseProxy/GitubSshHandler.cs
new file mode 100644
index 0000000..35c01c4
--- /dev/null
+++ b/FastGithub.ReverseProxy/GitubSshHandler.cs
@@ -0,0 +1,136 @@
+using FastGithub.DomainResolve;
+using Microsoft.AspNetCore.Connections;
+using System;
+using System.IO;
+using System.IO.Pipelines;
+using System.Net;
+using System.Net.Sockets;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace FastGithub.ReverseProxy
+{
+    /// <summary>
+    /// github的ssl处理者
+    /// </summary>
+    sealed class GitubSshHandler : ConnectionHandler
+    {
+        private const int SSH_PORT = 22;
+        private const string GITHUB_COM = "github.com";
+        private readonly IDomainResolver domainResolver;
+
+        /// <summary>
+        /// github的ssl处理者
+        /// </summary>
+        /// <param name="domainResolver"></param>
+        public GitubSshHandler(IDomainResolver domainResolver)
+        {
+            this.domainResolver = domainResolver;
+        }
+
+        /// <summary>
+        /// ssh连接后
+        /// </summary>
+        /// <param name="connection"></param>
+        /// <returns></returns>
+        public override async Task OnConnectedAsync(ConnectionContext connection)
+        {
+            var address = await this.domainResolver.ResolveAsync(GITHUB_COM, CancellationToken.None);
+            var socket = new Socket(address.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
+            await socket.ConnectAsync(new IPEndPoint(address, SSH_PORT));
+
+            using var upStream = new NetworkStream(socket, ownsSocket: true);
+            var downStream = new SshStream(connection.Transport);
+
+            var task1 = upStream.CopyToAsync(downStream);
+            var task2 = downStream.CopyToAsync(upStream);
+            await Task.WhenAny(task1, task2);
+        }
+
+        /// <summary>
+        /// 表示Ssh的流
+        /// </summary>
+        private class SshStream : Stream
+        {
+            private readonly Stream readStream;
+            private readonly Stream wirteStream;
+
+            /// <summary>
+            /// Ssh的流
+            /// </summary>
+            /// <param name="transport"></param>
+            public SshStream(IDuplexPipe transport)
+            {
+                this.readStream = transport.Input.AsStream();
+                this.wirteStream = transport.Output.AsStream();
+            }
+
+            public override bool CanRead => true;
+
+            public override bool CanSeek => false;
+
+            public override bool CanWrite => true;
+
+            public override long Length => throw new NotSupportedException();
+
+            public override long Position
+            {
+                get => throw new NotSupportedException();
+                set => throw new NotSupportedException();
+            }
+
+            public override void Flush()
+            {
+                this.wirteStream.Flush();
+            }
+
+            public override Task FlushAsync(CancellationToken cancellationToken)
+            {
+                return this.wirteStream.FlushAsync(cancellationToken);
+            }
+
+            public override long Seek(long offset, SeekOrigin origin)
+            {
+                throw new NotSupportedException();
+            }
+
+            public override void SetLength(long value)
+            {
+                throw new NotSupportedException();
+            }
+
+            public override int Read(byte[] buffer, int offset, int count)
+            {
+                return this.readStream.Read(buffer, offset, count);
+            }
+            public override void Write(byte[] buffer, int offset, int count)
+            {
+                this.wirteStream.Write(buffer, offset, count);
+            }
+            public override ValueTask<int> ReadAsync(Memory<byte> buffer, CancellationToken cancellationToken = default)
+            {
+                return this.readStream.ReadAsync(buffer, cancellationToken);
+            }
+
+            public override Task<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+            {
+                return this.readStream.ReadAsync(buffer, offset, count, cancellationToken);
+            }
+
+            public override void Write(ReadOnlySpan<byte> buffer)
+            {
+                this.wirteStream.Write(buffer);
+            }
+
+            public override Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+            {
+                return this.wirteStream.WriteAsync(buffer, offset, count, cancellationToken);
+            }
+
+            public override async ValueTask WriteAsync(ReadOnlyMemory<byte> buffer, CancellationToken cancellationToken = default)
+            {
+                await this.wirteStream.WriteAsync(buffer, cancellationToken);
+            }
+        }
+    }
+}
diff --git a/FastGithub.ReverseProxy/KestrelServerOptionsExtensions.cs b/FastGithub.ReverseProxy/KestrelServerOptionsExtensions.cs
index 353fc02..091c260 100644
--- a/FastGithub.ReverseProxy/KestrelServerOptionsExtensions.cs
+++ b/FastGithub.ReverseProxy/KestrelServerOptionsExtensions.cs
@@ -1,5 +1,6 @@
 using FastGithub.Configuration;
 using FastGithub.ReverseProxy;
+using Microsoft.AspNetCore.Connections;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.AspNetCore.Server.Kestrel.Core;
 using Microsoft.Extensions.DependencyInjection;
@@ -69,5 +70,29 @@ namespace FastGithub
                 https.ServerCertificateSelector = (ctx, domain) => certService.GetOrCreateServerCert(domain);
             }));
         }
+
+        /// <summary>
+        /// 监听github的ssh的代理
+        /// </summary>
+        /// <param name="kestrel"></param>
+        public static void ListenGithubSshProxy(this KestrelServerOptions kestrel)
+        {
+            const int SSH_PORT = 22;
+            if (OperatingSystem.IsWindows())
+            {
+                TcpTable.KillPortOwner(SSH_PORT);
+            }
+
+            if (LocalMachine.CanListenTcp(SSH_PORT) == false)
+            {
+                var loggerFactory = kestrel.ApplicationServices.GetRequiredService<ILoggerFactory>();
+                var logger = loggerFactory.CreateLogger($"{nameof(FastGithub)}.{nameof(ReverseProxy)}");
+                logger.LogWarning($"由于tcp端口{SSH_PORT}已经被其它进程占用，github的ssh代理功能将受限");
+            }
+            else
+            {
+                kestrel.Listen(IPAddress.Any, SSH_PORT, listen => listen.UseConnectionHandler<GitubSshHandler>());
+            }
+        }
     }
 }
diff --git a/FastGithub/Program.cs b/FastGithub/Program.cs
index 19ce9d4..51548d2 100644
--- a/FastGithub/Program.cs
+++ b/FastGithub/Program.cs
@@ -49,6 +49,7 @@ namespace FastGithub
                     webBuilder.UseKestrel(kestrel =>
                     {
                         kestrel.Limits.MaxRequestBodySize = null;
+                        kestrel.ListenGithubSshProxy();
                         kestrel.ListenHttpReverseProxy();
                         kestrel.ListenHttpsReverseProxy();
                     });