release: bump version to 0.57.0

scripts/windows-lan-relay.ps1

@@ -0,0 +1,103 @@
+param(
+    [string]$ListenAddress = "0.0.0.0",
+    [Parameter(Mandatory = $true)][int]$ListenPort,
+    [Parameter(Mandatory = $true)][string]$TargetHost,
+    [Parameter(Mandatory = $true)][int]$TargetPort,
+    [int]$IdleExitSeconds = 8
+)
+
+$ErrorActionPreference = "Stop"
+
+Add-Type -TypeDefinition @"
+using System;
+using System.Net;
+using System.Net.Sockets;
+using System.Threading.Tasks;
+
+public static class PlanetTcpRelay
+{
+    public static async Task RunAsync(string listenAddress, int listenPort, string targetHost, int targetPort, int idleExitSeconds)
+    {
+        IPAddress address;
+        if (!IPAddress.TryParse(listenAddress, out address))
+        {
+            address = IPAddress.Any;
+        }
+        var listener = new TcpListener(address, listenPort);
+        listener.Start();
+        var lastHealthyAt = DateTime.UtcNow;
+
+        try
+        {
+            while (true)
+            {
+                if (await CanConnectAsync(targetHost, targetPort))
+                {
+                    lastHealthyAt = DateTime.UtcNow;
+                }
+                else if ((DateTime.UtcNow - lastHealthyAt).TotalSeconds >= idleExitSeconds)
+                {
+                    break;
+                }
+
+                while (listener.Pending())
+                {
+                    var client = await listener.AcceptTcpClientAsync();
+                    _ = Task.Run(() => HandleClientAsync(client, targetHost, targetPort));
+                }
+
+                await Task.Delay(200);
+            }
+        }
+        finally
+        {
+            listener.Stop();
+        }
+    }
+
+    private static async Task<bool> CanConnectAsync(string host, int port)
+    {
+        using (var client = new TcpClient())
+        {
+            var connectTask = client.ConnectAsync(host, port);
+            var completed = await Task.WhenAny(connectTask, Task.Delay(500));
+            if (completed != connectTask)
+            {
+                return false;
+            }
+
+            try
+            {
+                await connectTask;
+                return client.Connected;
+            }
+            catch
+            {
+                return false;
+            }
+        }
+    }
+
+    private static async Task HandleClientAsync(TcpClient client, string targetHost, int targetPort)
+    {
+        using (client)
+        using (var upstream = new TcpClient())
+        {
+            try
+            {
+                await upstream.ConnectAsync(targetHost, targetPort);
+                var clientStream = client.GetStream();
+                var upstreamStream = upstream.GetStream();
+                var toUpstream = clientStream.CopyToAsync(upstreamStream);
+                var toClient = upstreamStream.CopyToAsync(clientStream);
+                await Task.WhenAny(toUpstream, toClient);
+            }
+            catch
+            {
+            }
+        }
+    }
+}
+"@
+
+[PlanetTcpRelay]::RunAsync($ListenAddress, $ListenPort, $TargetHost, $TargetPort, $IdleExitSeconds).GetAwaiter().GetResult()