refactored app common project

DnsServerCore.ApplicationCommon/IDnsRequestController.cs

@@ -0,0 +1,71 @@
+/*
+Technitium DNS Server
+Copyright (C) 2021  Shreyas Zare (shreyas@technitium.com)
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+*/
+
+using System;
+using System.Net;
+using System.Threading.Tasks;
+using TechnitiumLibrary.Net.Dns;
+
+namespace DnsServerCore.ApplicationCommon
+{
+    public enum DnsRequestControllerAction
+    {
+        /// <summary>
+        /// Allow the request to be processed.
+        /// </summary>
+        Allow = 0,
+
+        /// <summary>
+        /// Drop the request without any response.
+        /// </summary>
+        DropSilently = 1,
+
+        /// <summary>
+        /// Drop the request with a Refused response.
+        /// </summary>
+        DropWithRefused = 2
+    }
+
+    /// <summary>
+    /// Allows a DNS App to inspect and optionally block incoming DNS requests before they are processed by the DNS Server core.
+    /// </summary>
+    public interface IDnsRequestController : IDisposable
+    {
+        /// <summary>
+        /// Allows initializing the DNS application with a config. This function is also called when the config is updated to allow reloading.
+        /// </summary>
+        /// <param name="dnsServer">The DNS server interface object that allows access to DNS server properties.</param>
+        /// <param name="config">The DNS application config stored in the <c>dnsApp.config</c> file.</param>
+        Task InitializeAsync(IDnsServer dnsServer, string config);
+
+        /// <summary>
+        /// Allows a DNS App to inspect an incoming DNS request and decide whether to allow or block it. This method is called by the DNS Server before an incoming request is processed.
+        /// </summary>
+        /// <param name="request">The incoming DNS request.</param>
+        /// <param name="remoteEP">The end point (IP address and port) of the client making the request.</param>
+        /// <param name="protocol">The protocol using which the request was received.</param>
+        /// <returns>The action that must be taken by the DNS server i.e. if the request must be allowed or dropped.</returns>
+        Task<DnsRequestControllerAction> GetRequestActionAsync(DnsDatagram request, IPEndPoint remoteEP, DnsTransportProtocol protocol);
+
+        /// <summary>
+        /// The description about this app to be shown in the Apps section of the DNS web console.
+        /// </summary>
+        string Description { get; }
+    }
+}