DnsServer: updated code to implement AuthZoneManager, CacheZoneManager and BlockListZoneManager. Implemented new recursive resolver code using wait handles to fix thread contention issues. Removed doh-servers-associated json response support. Changed zone processing sequence to auth, allowed, blocked, blocklist, and finally recursive. Implemented CNAME cloaking checks. Code refactoring done.

DnsServerCore/Dns/ResolverQueryHandle.cs

@@ -0,0 +1,50 @@
+/*
+Technitium DNS Server
+Copyright (C) 2020  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.Threading;
+using TechnitiumLibrary.Net.Dns;
+
+namespace DnsServerCore.Dns
+{
+    class ResolverQueryHandle
+    {
+        #region variables
+
+        DnsDatagram _response;
+        readonly EventWaitHandle _waitHandle = new ManualResetEvent(false);
+
+        #endregion
+
+        #region public
+
+        public void Set(DnsDatagram response)
+        {
+            _response = response;
+            _waitHandle.Set();
+        }
+
+        public DnsDatagram WaitForResponse(int timeout)
+        {
+            _waitHandle.WaitOne(timeout);
+            return _response;
+        }
+
+        #endregion
+    }
+}