Feature/merge upstream

.gitignore

@@ -7,6 +7,7 @@ Dns.Cli/dns.db*
 *.suo
 *.user
 *.sln.docstates
+*.orig
 
 # Build results
 

AGENTS.md

@@ -0,0 +1,85 @@
+# AGENTS GUIDE
+
+> Scope: assistants may edit **code, tests, and documentation** in this repository. Infrastructure/deployment assets remain off-limits unless explicitly approved.
+
+## 1. Mission
+- Maintain and extend the `csharp-dns-server` so it becomes a production-ready DNS service with rich testing, observability, and zone-provider capabilities.
+- Follow the roadmap in `docs/product_requirements.md`, respect the priority tiers in `docs/priorities.md` (P0 reliability/protocol accuracy, P1 security & maintenance, P2 features), and focus on open GitHub issues aligned with those tiers.
+- Reference the prioritized backlog in `docs/task_list.md` when picking up work to stay aligned with near-term goals.
+
+## 2. Repository Orientation
+| Project | Purpose | Notes |
+|---------|---------|-------|
+| `Dns/` | Core library implementing DNS protocol, server loop, zone providers, HTTP status surface. | Entry point: `Dns/Program.cs`. Zone providers under `Dns/ZoneProvider`. |
+| `dns-cli/` | Console host that runs the DNS server for local testing. | Mirrors `Dns/appsettings.json`. |
+| `dnstest/` | xUnit suite covering protocol/utility components. | Expand here before adding new test assemblies. |
+| `docs/` | Specs, PRD and future design docs. | `docs/product_requirements.md` drives priorities. |
+
+Key classes & files:
+- `Dns/Program.cs`: wiring for DI/config/servers via `Microsoft.Extensions.DependencyInjection`.
+- `Dns/DnsServer.cs`: UDP DNS loop and upstream forwarding.
+- `Dns/SmartZoneResolver.cs`: in-memory zone cache & round-robin dispenser.
+- `Dns/HttpServer.cs`: embedded status/diagnostics surface.
+- `Dns/ZoneProvider/**`: implementations (CSV, IP probes, BIND placeholder).
+
+## 3. Getting Started
+```bash
+# restore & build
+dotnet build csharp-dns-server.sln
+
+# run tests
+dotnet test csharp-dns-server.sln
+
+# run server (localhost)
+cd dns-cli
+dotnet run -- ./appsettings.json
+```
+Gotchas:
+- UDP port 53 may be taken by Docker/ICS on Windows; change listener port in `appsettings.json`.
+- `Dns/appsettings.json` is copied to output; edit with care when adding samples.
+- Zone providers may depend on local files (CSV) or ping-able IPs—mock or isolate tests accordingly.
+
+## 4. Coding Standards
+- C# 8 / .NET 3.1 currently, migrating to .NET 8 (see PRD). Prefer idiomatic C# and existing project style.
+- Keep ASCII unless file already uses Unicode.
+- Windows (/r/n) line delimiters
+- Prefer spaces not tabs
+- Add comments only where logic is non-obvious.
+- ```dotnet format``` all code before submission
+- MIT license headers already present — preserve them.
+
+## 5. Allowed / Disallowed Work
+- ✅ Modify C# source, tests, sample configs, docs within `docs/` and root (`AGENTS.md`, README).
+- ✅ Add new tests or scripts that live in-repo (delete temporary tooling before submitting).
+- 🚫 Do **not** edit deployment/infrastructure assets (Dockerfiles, systemd service files, external config stores) unless explicitly authorized by a maintainer.
+- 🚫 No secret management or external network calls without approval.
+
+## 6. Workflow
+1. **Plan**: understand issue context (link to PRD sections). If multiple files touched, outline steps before coding.
+2. **Implement**: keep changes scoped; ensure zone providers/tests stay deterministic.
+3. **Validate**: run `dotnet build` and relevant `dotnet test` subsets. Document skipped tests or environment assumptions.
+4. **Document**: update `docs/` where appropriate.  Update README when adding features, config switches and any other project-wide relevant information.
+5. **Submit Pull Request**: run `dotnet format`.  Follow the contribution workflow in README (squash commits, include rationale).
+
+## 7. Testing Expectations
+- Minimum: `dotnet test csharp-dns-server.sln`.
+- The dns-cli integration harness (`dnstest/Integration` + `DnsCliAuthoritativeBehaviorTests`) runs automatically with `dotnet test`, spins up `dns-cli` using the sample assets in `dnstest/TestData`, and needs free TCP/UDP ports; keep configs deterministic when extending it.
+- For networking changes, add/extend unit tests in `dnstest` or new integration fixtures.
+- Capture repro cases for fixed bugs (#26 compressed pointers, #11 BitPacker write) and ensure tests fail before fixes.
+
+## 8. Observability & Diagnostics
+- Prefer structured logging (use `Console.WriteLine` only as placeholder).
+- When adding metrics or tracing, integrate with future Prometheus/OTel plan (see PRD §4).
+
+## 9. Communication & Review
+- DO STOP and ask questions if there is missing, ambiguous, or inconsistent information.
+- Document assumptions and remaining risks in PR descriptions.
+- If blocked by environmental constraints (e.g., network access), leave instructions for a maintainer.
+- Keep PRs focused; split unrelated fixes.
+
+## 10. Safety & Guardrails
+- Treat `appsettings.json` samples as templates—do not embed secrets.
+- Respect the agent scope limit: no infrastructure edits.
+- When unsure, create an issue/comment instead of guessing.
+
+Thank you for helping build a reliable C# DNS server!

Directory.Build.props

@@ -10,7 +10,7 @@
     </ItemGroup>
 
     <ItemGroup>
-        <PackageReference Include="ConfigureAwaitChecker.Analyzer" Version="5.0.0.1">
+        <PackageReference Include="ConfigureAwaitChecker.Analyzer" Version="5.0.0.1" Condition="$(DebugProject) != true">
             <PrivateAssets>all</PrivateAssets>
             <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
         </PackageReference>

Dns.Cli/Migrations/20251011113400_InitialCreate.cs

@@ -1,6 +1,6 @@
-using Microsoft.EntityFrameworkCore.Migrations;
+#nullable disable
 
-#nullable disable
+using Microsoft.EntityFrameworkCore.Migrations;
 
 namespace Dns.Cli.Migrations
 {

Dns.Cli/Migrations/20251012125120_Rev1.cs

@@ -1,6 +1,6 @@
-using Microsoft.EntityFrameworkCore.Migrations;
+#nullable disable
 
-#nullable disable
+using Microsoft.EntityFrameworkCore.Migrations;
 
 namespace Dns.Cli.Migrations
 {

Dns.Cli/Migrations/20251012131553_Rev2.cs

@@ -1,6 +1,6 @@
-using Microsoft.EntityFrameworkCore.Migrations;
+#nullable disable
 
-#nullable disable
+using Microsoft.EntityFrameworkCore.Migrations;
 
 namespace Dns.Cli.Migrations
 {

Dns.Cli/Migrations/DnsServerDbContextModelSnapshot.cs

@@ -1,11 +1,10 @@
 // <auto-generated />
-using System;
+
+#nullable disable
+
 using Dns.Db.Contexts;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.EntityFrameworkCore.Infrastructure;
-using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
-
-#nullable disable
 
 namespace Dns.Cli.Migrations
 {

Dns.Cli/Program.cs

@@ -1,5 +1,5 @@
+using System.IO;
 using System.Threading.Tasks;
-using Microsoft.AspNetCore;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.Hosting;
@@ -21,10 +21,20 @@ public static Task Main(string[] args)
 	private static IHostBuilder CreateWebHostBuilder(string[] args) =>
 		Host.CreateDefaultBuilder(args)
 		    .ConfigureAppConfiguration(
-			    (_, config) =>
+			    (context, config) =>
 			    {
 				    config.AddEnvironmentVariables();
 				    config.AddCommandLine(args);
+				    var tempConfig = config.Build();
+				    var customPath = tempConfig["appsettings"];
+
+				    if (!string.IsNullOrWhiteSpace(customPath))
+				    {
+					    if (File.Exists(customPath))
+					    {
+						    config.AddJsonFile(customPath, optional: false, reloadOnChange: true);
+					    }
+				    }
 			    }
 		    )
 		    .ConfigureWebHostDefaults(webHost => webHost.UseStartup<Startup>());

Dns.Cli/Startup.cs

@@ -11,7 +11,6 @@
 using Dns.Config;
 using Dns.Contracts;
 using Dns.Db.Configuration;
-using Dns.Db.Contexts;
 using Dns.Db.Extensions;
 using Dns.Handlers;
 using Dns.Services;
@@ -25,7 +24,6 @@
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.AspNetCore.Mvc.Formatters;
 using Microsoft.AspNetCore.ResponseCompression;
-using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.DependencyInjection.Extensions;
@@ -227,4 +225,4 @@ public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
 		app.UseAuthorization();
 		app.UseEndpoints(endpoints => { endpoints.MapControllers(); });
 	}
-}
+}

Dns.Db/Models/EntityFramework/Enums/ResourceClass.cs

@@ -13,4 +13,4 @@ public enum ResourceClass : ushort
     CS   = 2,
     CH   = 3,
     HS   = 4,
-}
+}

Dns.Db/Repositories/UserRepository.cs

@@ -1,5 +1,4 @@
-using System.Globalization;
-using Dns.Db.Contexts;
+using Dns.Db.Contexts;
 using Dns.Db.Models.EntityFramework;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.Logging;

Dns.UnitTests/BindZoneProviderTests.cs

@@ -0,0 +1,116 @@
+// // //-------------------------------------------------------------------------------------------------
+// // // <copyright file="BindZoneProviderTests.cs" company="stephbu">
+// // // Copyright (c) Steve Butler. All rights reserved.
+// // // </copyright>
+// // //-------------------------------------------------------------------------------------------------
+
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using Dns.Db.Models.EntityFramework.Enums;
+using Dns.UnitTests.Integration;
+using Dns.ZoneProvider;
+using Dns.ZoneProvider.Bind;
+using Microsoft.Extensions.Logging.Testing;
+using Xunit;
+
+namespace Dns.UnitTests;
+
+public class BindZoneProviderTests
+{
+    [Fact]
+    public void GenerateZone_ReturnsZoneRecordsFromBindFile()
+    {
+        var zoneFile = Path.Combine(TestProjectPaths.TestDataDirectory, "Bind", "simple.zone");
+
+        using var provider = CreateProvider(zoneFile);
+        var      zone     = provider.GenerateZone();
+
+        Assert.NotNull(zone);
+        Assert.Equal("example.com", zone.Suffix);
+        Assert.Equal(0u, zone.Serial);
+
+        var filteredRecords = zone.Records.Where(record => record.Host == "www.example.com" && record.Type == ResourceType.A);
+
+        var wwwA = Assert.Single(filteredRecords);
+        Assert.Equal("192.0.2.10", Assert.Single(wwwA.Addresses));
+
+        filteredRecords = zone.Records.Where(record => record.Host == "www.example.com" && record.Type == ResourceType.AAAA);
+        var wwwAaaa = Assert.Single(filteredRecords);
+        Assert.Equal("2001:db8::10", Assert.Single(wwwAaaa.Addresses));
+
+        filteredRecords = zone.Records.Where(record => record.Host == "example.com" && record.Type == ResourceType.A);
+
+        var apex = Assert.Single(filteredRecords);
+        Assert.Contains("192.0.2.20", apex.Addresses);
+
+        filteredRecords = zone.Records.Where(record => record.Host == "api.example.com");
+        var api = Assert.Single(filteredRecords);
+        Assert.Equal("192.0.2.30", Assert.Single(api.Addresses));
+    }
+
+    [Fact]
+    public void GenerateZone_InvalidZoneReturnsNull()
+    {
+        var zoneFile = Path.Combine(TestProjectPaths.TestDataDirectory, "Bind", "invalid_missing_ttl.zone");
+
+        using var provider = CreateProvider(zoneFile);
+        var      zone     = provider.GenerateZone();
+
+        Assert.Null(zone);
+    }
+
+    [Fact]
+    public void GenerateZone_ReturnsNullWhenCNameConflictsWithAddress()
+    {
+        var tempZone = WriteTempZoneFile(
+        [
+            "$TTL 1h",
+            "$ORIGIN example.com.",
+            "@ IN SOA ns1.example.com. hostmaster.example.com. (",
+            "    2024010101",
+            "    7200",
+            "    3600",
+            "    1209600",
+            "    3600 )",
+            "@ IN NS ns1.example.com.",
+            "www IN CNAME api",
+            "www IN A 192.0.2.40",
+            "api IN A 192.0.2.50",
+        ]
+        );
+
+        try
+        {
+            using var provider = CreateProvider(tempZone);
+            var       zone     = provider.GenerateZone();
+
+            Assert.Null(zone);
+        }
+        finally
+        {
+            File.Delete(tempZone);
+        }
+    }
+
+    private BindZoneProvider CreateProvider(string zoneFile)
+    {
+        var provider = new BindZoneProvider(new FakeLogger<BindZoneProvider>(), new SmartZoneResolver(new FakeLogger<SmartZoneResolver>()));
+        provider.Initialize(new()
+        {
+            Name = "example.com",
+            ProviderSettings = new FileWatcherZoneProviderSettings
+            {
+                FileName = zoneFile,
+            },
+        });
+        return provider;
+    }
+
+    private string WriteTempZoneFile(IEnumerable<string> lines)
+    {
+        var path = Path.GetTempFileName();
+        File.WriteAllLines(path, lines);
+        return path;
+    }
+}