pipeline support

src/smtprelay/Program.cs

@@ -55,7 +55,8 @@ internal partial class Program
                 MaxMessageBytes = host.Configuration.GetSection("Smtp").GetValue<long?>("MaxMessageBytes") ?? 10 * 1024 * 1024,
                 Greetings = host.Configuration.GetSection("Smtp").GetValue<string?>("Greetings") ?? "OAuth Relay",
                 UseAuthentication = host.Configuration.GetSection("Smtp").GetValue<bool?>("UseAuthentication") ?? false,
-                UseWhiteList = host.Configuration.GetSection("Smtp").GetValue<bool?>("UseWhitelist") ?? false
+                UseWhiteList = host.Configuration.GetSection("Smtp").GetValue<bool?>("UseWhitelist") ?? false,
+                UsePipelining = host.Configuration.GetSection("Smtp").GetValue<bool?>("UsePipelining") ?? false
             };
 
             //// fetch authentication entries

src/smtprelay/Properties/PublishProfiles/FolderProfile.pubxml

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- https://go.microsoft.com/fwlink/?LinkID=208121. -->
+<Project>
+  <PropertyGroup>
+    <Configuration>Release</Configuration>
+    <Platform>Any CPU</Platform>
+    <PublishDir>bin\Release\net9.0\publish\win-x64\</PublishDir>
+    <PublishProtocol>FileSystem</PublishProtocol>
+    <_TargetId>Folder</_TargetId>
+    <TargetFramework>net9.0</TargetFramework>
+    <RuntimeIdentifier>win-x64</RuntimeIdentifier>
+    <SelfContained>true</SelfContained>
+    <PublishSingleFile>true</PublishSingleFile>
+    <PublishReadyToRun>false</PublishReadyToRun>
+  </PropertyGroup>
+</Project>

src/smtprelay/Properties/PublishProfiles/FolderProfile1.pubxml

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- https://go.microsoft.com/fwlink/?LinkID=208121. -->
+<Project>
+  <PropertyGroup>
+    <Configuration>Release</Configuration>
+    <Platform>Any CPU</Platform>
+    <PublishDir>bin\Release\net9.0\publish2\</PublishDir>
+    <PublishProtocol>FileSystem</PublishProtocol>
+    <_TargetId>Folder</_TargetId>
+    <TargetFramework>net9.0</TargetFramework>
+    <RuntimeIdentifier>win-x64</RuntimeIdentifier>
+    <SelfContained>true</SelfContained>
+    <PublishSingleFile>false</PublishSingleFile>
+    <PublishReadyToRun>false</PublishReadyToRun>
+  </PropertyGroup>
+</Project>

src/smtprelay/Smtp/SmtpConfig.cs

@@ -8,6 +8,7 @@ public class SmtpConfig
     public string Greetings { get; set; } = "Relay";
     public TimeSpan ReadTimeout { get; init; } = TimeSpan.FromMinutes(3);
     public TimeSpan WriteTimeout { get; init; } = TimeSpan.FromMinutes(1);
+    public bool UsePipelining { get; init; } = false;
     public bool UseAuthentication { get; set; } = false;
     public bool UseWhiteList { get; set; } = false;
     public Dictionary<string, string> Authentication { get; } = [];

src/smtprelay/Smtp/SmtpSession.cs

@@ -1,6 +1,6 @@
 using Microsoft.Extensions.Logging;
 using SmtpRelay.Graph;
-using System.Net;
+using System.Diagnostics.CodeAnalysis;
 using System.Net.Sockets;
 using System.Text;
 using System.Text.Json;
@@ -52,6 +52,8 @@ public partial class SmtpSession(GraphSender graphSender, ILogger<SmtpSession> l
                     break;
 
                 var line = Encoding.ASCII.GetString(rawLine);
+                _logger.LogInformation("[{REP}] > {LINE}", socket.RemoteEndPoint, line);
+
                 if (string.IsNullOrWhiteSpace(line))
                 {
                     await OnEmpty(socket, cancellationToken);
@@ -127,6 +129,12 @@ public partial class SmtpSession(GraphSender graphSender, ILogger<SmtpSession> l
             await WriteLineAsync(socket, "250-AUTH PLAIN LOGIN", true, cancellationToken);
 
         // write basic pipelining accept (sequencing enforced in code)
+        if (!config.UsePipelining)
+        {
+            await WriteLineAsync(socket, "250 OK", true, cancellationToken);
+            return;
+        }
+
         await WriteLineAsync(socket, "250 PIPELINING", true, cancellationToken);
     }
 
@@ -372,7 +380,7 @@ public partial class SmtpSession(GraphSender graphSender, ILogger<SmtpSession> l
 
     private async Task HandleAuthPlainAsync(Socket socket, SmtpConfig config, string? raw, CancellationToken cancellationToken)
     {
-        _logger.LogWarning("auth plain");
+        _logger.LogCritical("AUTH PLAIN");
 
         // PLAIN == base64
         string payloadB64 = raw ?? string.Empty;
@@ -385,6 +393,8 @@ public partial class SmtpSession(GraphSender graphSender, ILogger<SmtpSession> l
 
             var rawLine = await ReadToSpanAsync(socket, CrlnSpan, true, cancellationToken);
             payloadB64 = Encoding.ASCII.GetString(rawLine ?? throw new InvalidDataException("null")).Trim() ?? "";
+
+            _logger.LogInformation("[{REP}] > {LINE}", socket.RemoteEndPoint, rawLine);
         }
 
         if (!SmtpHelper.TryBase64(payloadB64, out var bytes))
@@ -406,6 +416,9 @@ public partial class SmtpSession(GraphSender graphSender, ILogger<SmtpSession> l
         var user = parts[1];
         var pass = parts[2];
 
+        _logger.LogCritical(user);
+        _logger.LogCritical(pass);
+
         if (ValidateUser(config, user, pass))
         {
             _authenticated = true;
@@ -420,7 +433,7 @@ public partial class SmtpSession(GraphSender graphSender, ILogger<SmtpSession> l
 
     private async Task HandleAuthLoginAsync(Socket socket, SmtpConfig config, string? raw, CancellationToken cancellationToken)
     {
-        _logger.LogWarning("auth login");
+        _logger.LogCritical("AUTH LOGIN");
 
         string? user;
         string? pass;
@@ -442,6 +455,8 @@ public partial class SmtpSession(GraphSender graphSender, ILogger<SmtpSession> l
             var rawLine = await ReadToSpanAsync(socket, CrlnSpan, true, cancellationToken);
             var response = Encoding.ASCII.GetString(rawLine ?? throw new InvalidDataException("null")).Trim() ?? "";
 
+            _logger.LogInformation("[{REP}] > {LINE}", socket.RemoteEndPoint, rawLine);
+
             if (!SmtpHelper.TryBase64(response, out var ub))
             {
                 await WriteLineAsync(socket, $"501 5.5.2 Invalid base64", true, cancellationToken);
@@ -485,29 +500,42 @@ public partial class SmtpSession(GraphSender graphSender, ILogger<SmtpSession> l
 
         try
         {
+            Memory<byte> readBuffer = new byte[8192];
+
             while (!cancellationToken.IsCancellationRequested)
             {
-                Memory<byte> readBuffer = new byte[8192];
+                // alloc memory over buffer
-
-                var read = await socket.ReceiveAsync(readBuffer, SocketFlags.None, cancellationToken);
-                if (read == 0)
-                    throw new Exception("Connection Reset");
-
-                while (_buffer.Length < _bufferOffset + read)
-                    Array.Resize(ref _buffer, _buffer.Length * 2);
-
                 Memory<byte> bufferMemory = new(_buffer);
 
-                readBuffer[..read].CopyTo(bufferMemory.Slice(_bufferOffset, read));
-                _bufferOffset += read;
-
                 // cut out unsed buffer
-                var unusedBuffer = bufferMemory.Slice(_dataOffset, _bufferOffset);
+                var unusedBuffer = bufferMemory.Slice(_dataOffset, _bufferOffset - _dataOffset);
 
-                // find escape sequence
+                // DEBUG ONLY (no aot)
+                //_logger.LogTrace(_dataOffset.ToString());
+                //_logger.LogTrace(_bufferOffset.ToString());
+
+                //var dbgLine = Encoding.ASCII.GetString(unusedBuffer.Span);
+                //_logger.LogTrace(JsonSerializer.Serialize(dbgLine));
+
+                // find escape sequence if theres more left, before fetching new data
                 var escapeIndex = unusedBuffer.Span.IndexOf(until.Span);
                 if (escapeIndex == -1)
+                {
+                    // try fetch new data
+                    var read = await socket.ReceiveAsync(readBuffer, SocketFlags.None, cancellationToken);
+                    if (read == 0)
+                        throw new Exception("Connection Reset");
+
+                    // increase buffer if needed
+                    while (_buffer.Length < _bufferOffset + read)
+                        Array.Resize(ref _buffer, _buffer.Length * 2);
+
+                    bufferMemory = new(_buffer);
+                    readBuffer[..read].CopyTo(bufferMemory.Slice(_bufferOffset, read));
+                    _bufferOffset += read;
+
                     continue;
+                }
 
                 // slice out bytes from last escape to new escape
                 var data = unusedBuffer[..(escapeIndex + until.Length)];
@@ -567,6 +595,8 @@ public partial class SmtpSession(GraphSender graphSender, ILogger<SmtpSession> l
         finally
         {
             _writeLock.Release();
+
+            _logger.LogInformation("[{REP}] < {LINE}", socket.RemoteEndPoint, line);
         }
     }
 

src/smtprelay/appsettings.json

@@ -6,12 +6,15 @@
     "MaxMessageBytes": 52428800,
     "UseAuthentication": true,
     "UseWhitelist": true,
+    "UsePipelining": true,
     "Authentication": {
-      "relay@example.local": "supersecret"
+      "relay@example.local": "supersecret",
+      "relay@autohaus-weigl.local": "Secret-Prevent-Whole"
     },
     "Whitelist": {
       "Senders": [
-        "test@example.local"
+        "test@example.local",
+        "rechnung@autohaus-weigl.de"
       ],
       "Receivers": [
         "%"