added SecondaryForwarderZone

DnsServerCore/Dns/Zones/SecondaryForwarderZone.cs

@@ -0,0 +1,160 @@
+/*
+Technitium DNS Server
+Copyright (C) 2024  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 DnsServerCore.Dns.ResourceRecords;
+using System;
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using TechnitiumLibrary.Net.Dns;
+using TechnitiumLibrary.Net.Dns.ResourceRecords;
+
+namespace DnsServerCore.Dns.Zones
+{
+    class SecondaryForwarderZone : SecondaryZone
+    {
+        #region constructor
+
+        public SecondaryForwarderZone(DnsServer dnsServer, AuthZoneInfo zoneInfo)
+            : base(dnsServer, zoneInfo)
+        { }
+
+        public SecondaryForwarderZone(DnsServer dnsServer, string name, IReadOnlyList<NameServerAddress> primaryNameServerAddresses, DnsTransportProtocol primaryZoneTransferProtocol = DnsTransportProtocol.Tcp, string primaryZoneTransferTsigKeyName = null)
+            : base(dnsServer, name, primaryNameServerAddresses, primaryZoneTransferProtocol, primaryZoneTransferTsigKeyName, false)
+        {
+            InitZone();
+        }
+
+        #endregion
+
+        #region protected
+
+        protected virtual void InitZone()
+        {
+            //init secondary forwarder zone with dummy SOA record
+            DnsSOARecordData soa = new DnsSOARecordData(_dnsServer.ServerDomain, "invalid", 0, 900, 300, 604800, 900);
+            DnsResourceRecord soaRecord = new DnsResourceRecord(_name, DnsResourceRecordType.SOA, DnsClass.IN, 0, soa);
+            soaRecord.GetAuthGenericRecordInfo().LastModified = DateTime.UtcNow;
+
+            _entries[DnsResourceRecordType.SOA] = [soaRecord];
+        }
+
+        protected override Task FinalizeZoneTransferAsync()
+        {
+            //secondary forwarder does not maintain zone history
+            return Task.CompletedTask;
+        }
+
+        protected override Task FinalizeIncrementalZoneTransferAsync(IReadOnlyList<DnsResourceRecord> historyRecords)
+        {
+            //secondary forwarder does not maintain zone history
+            return Task.CompletedTask;
+        }
+
+        #endregion
+
+        #region public
+
+        public override string GetZoneTypeName()
+        {
+            return "Secondary Forwarder";
+        }
+
+        public override IReadOnlyList<DnsResourceRecord> QueryRecords(DnsResourceRecordType type, bool dnssecOk)
+        {
+            if (type == DnsResourceRecordType.SOA)
+                return []; //secondary forwarder zone is not authoritative and contains dummy SOA record
+
+            return base.QueryRecords(type, dnssecOk);
+        }
+
+        #endregion
+
+        #region properties
+
+        public override bool OverrideCatalogPrimaryNameServers
+        {
+            get { throw new InvalidOperationException(); }
+            set { throw new InvalidOperationException(); }
+        }
+
+        public override AuthZoneQueryAccess QueryAccess
+        {
+            get { return base.QueryAccess; }
+            set
+            {
+                switch (value)
+                {
+                    case AuthZoneQueryAccess.AllowOnlyZoneNameServers:
+                    case AuthZoneQueryAccess.AllowZoneNameServersAndUseSpecifiedNetworkACL:
+                        throw new ArgumentException("The Query Access option is invalid for Secondary Conditional Forwarder zones: " + value.ToString(), nameof(QueryAccess));
+                }
+
+                base.QueryAccess = value;
+            }
+        }
+
+        public override AuthZoneTransfer ZoneTransfer
+        {
+            get { return base.ZoneTransfer; }
+            set { throw new InvalidOperationException(); }
+        }
+
+        public override AuthZoneNotify Notify
+        {
+            get { return base.Notify; }
+            set { throw new InvalidOperationException(); }
+        }
+
+        public override AuthZoneUpdate Update
+        {
+            get { return base.Update; }
+            set
+            {
+                switch (value)
+                {
+                    case AuthZoneUpdate.AllowOnlyZoneNameServers:
+                    case AuthZoneUpdate.AllowZoneNameServersAndUseSpecifiedNetworkACL:
+                        throw new ArgumentException("The Dynamic Updates option is invalid for Secondary Conditional Forwarder zones: " + value.ToString(), nameof(Update));
+                }
+
+                base.Update = value;
+            }
+        }
+
+        public override IReadOnlyList<NameServerAddress> PrimaryNameServerAddresses
+        {
+            get { return base.PrimaryNameServerAddresses; }
+            set
+            {
+                if ((value is null) || (value.Count == 0))
+                    throw new ArgumentException("At least one primary name server address must be specified for " + GetZoneTypeName() + " zone.", nameof(PrimaryNameServerAddresses));
+
+                base.PrimaryNameServerAddresses = value;
+            }
+        }
+
+        public override bool ValidateZone
+        {
+            get { return base.ValidateZone; }
+            set { throw new InvalidOperationException(); }
+        }
+
+        #endregion
+    }
+}