SecondaryZone: implemented zone refresh from primary zone.

DnsServerCore/Dns/Zones/SecondaryZone.cs

@@ -17,8 +17,11 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 */
 
+using DnsServerCore.Dns.ResourceRecords;
 using System;
 using System.Collections.Generic;
+using System.Net;
+using System.Threading;
 using TechnitiumLibrary.Net.Dns;
 using TechnitiumLibrary.Net.Dns.ResourceRecords;
 
@@ -26,42 +29,297 @@ namespace DnsServerCore.Dns.Zones
 {
     public sealed class SecondaryZone : AuthZone
     {
+        #region variables
+
+        readonly DnsServer _dnsServer;
+
+        DateTime _lastRefreshed;
+        readonly Timer _refreshTimer;
+        const int REFRESH_TIMER_INITIAL_INTERVAL = 30000;
+
+        const int REFRESH_TIMEOUT = 60000;
+        const int REFRESH_RETRIES = 5;
+
+        #endregion
+
         #region constructor
 
-        public SecondaryZone(string name, DnsSOARecord soa)
-            : base(name, soa)
-        { }
-
-        public SecondaryZone(string name, bool disabled)
-            : base(name)
+        public SecondaryZone(DnsServer dnsServer, AuthZoneInfo zoneInfo)
+            : base(zoneInfo.Name)
         {
-            _disabled = disabled;
+            _dnsServer = dnsServer;
+
+            _disabled = zoneInfo.Disabled;
+            _lastRefreshed = zoneInfo.LastRefreshed;
+
+            _refreshTimer = new Timer(RefreshTimerCallback, null, Timeout.Infinite, Timeout.Infinite);
+        }
+
+        public SecondaryZone(DnsServer dnsServer, string name, DnsSOARecord soa)
+            : base(name, soa)
+        {
+            _dnsServer = dnsServer;
+
+            _refreshTimer = new Timer(RefreshTimerCallback, null, Timeout.Infinite, Timeout.Infinite);
+        }
+
+        #endregion
+
+        #region IDisposable
+
+        bool _disposed;
+
+        protected override void Dispose(bool disposing)
+        {
+            if (_disposed)
+                return;
+
+            if (disposing)
+            {
+                if (_refreshTimer != null)
+                    _refreshTimer.Dispose();
+            }
+
+            _disposed = true;
+        }
+
+        #endregion
+
+        #region private
+
+        private void RefreshTimerCallback(object state)
+        {
+            if (_disabled)
+                return;
+
+            DnsResourceRecord record = _entries[DnsResourceRecordType.SOA][0];
+            DnsSOARecord soaRecord = record.RDATA as DnsSOARecord;
+
+            try
+            {
+                if ((_lastRefreshed > DateTime.MinValue) && (DateTime.UtcNow > _lastRefreshed.AddSeconds(soaRecord.Expire)))
+                {
+                    //zone expired!
+                    //disable zone so that server wont respond as authoritative
+                    _disabled = true;
+                }
+
+                string nsDomain = soaRecord.MasterNameServer;
+                List<NameServerAddress> nameServers = new List<NameServerAddress>();
+
+                IReadOnlyList<DnsResourceRecord> glueRecords = record.GetGlueRecords();
+                if (glueRecords.Count > 0)
+                {
+                    foreach (DnsResourceRecord glueRecord in glueRecords)
+                    {
+                        switch (glueRecord.Type)
+                        {
+                            case DnsResourceRecordType.A:
+                                nameServers.Add(new NameServerAddress(nsDomain, (glueRecord.RDATA as DnsARecord).Address));
+                                break;
+
+                            case DnsResourceRecordType.AAAA:
+                                if (_dnsServer.PreferIPv6)
+                                    nameServers.Add(new NameServerAddress(nsDomain, (glueRecord.RDATA as DnsAAAARecord).Address));
+
+                                break;
+                        }
+                    }
+                }
+                else
+                {
+                    //resolve addresses
+                    DnsDatagram response = _dnsServer.DirectQuery(new DnsQuestionRecord(nsDomain, DnsResourceRecordType.A, DnsClass.IN));
+                    if (response != null)
+                    {
+                        IReadOnlyList<IPAddress> addresses = DnsClient.ParseResponseA(response);
+                        foreach (IPAddress address in addresses)
+                            nameServers.Add(new NameServerAddress(nsDomain, address));
+                    }
+
+                    if (_dnsServer.PreferIPv6)
+                    {
+                        response = _dnsServer.DirectQuery(new DnsQuestionRecord(nsDomain, DnsResourceRecordType.AAAA, DnsClass.IN));
+                        if (response != null)
+                        {
+                            IReadOnlyList<IPAddress> addresses = DnsClient.ParseResponseAAAA(response);
+                            foreach (IPAddress address in addresses)
+                                nameServers.Add(new NameServerAddress(nsDomain, address));
+                        }
+                    }
+                }
+
+                //refresh zone
+                foreach (NameServerAddress nameServer in nameServers)
+                {
+                    if (RefreshZone(nameServer))
+                    {
+                        //zone refreshed; set timer for refresh
+                        DnsSOARecord latestSoaRecord = _entries[DnsResourceRecordType.SOA][0].RDATA as DnsSOARecord;
+                        _refreshTimer.Change(latestSoaRecord.Refresh * 1000, Timeout.Infinite);
+
+                        _lastRefreshed = DateTime.UtcNow;
+                        _dnsServer.AuthZoneManager.SaveZoneFile(_name);
+                        return;
+                    }
+                }
+
+                //no response from any of the name servers; set timer for retry
+                _refreshTimer.Change(soaRecord.Retry * 1000, Timeout.Infinite);
+            }
+            catch (Exception ex)
+            {
+                LogManager log = _dnsServer.LogManager;
+                if (log != null)
+                    log.Write(ex);
+
+                //set timer for retry
+                _refreshTimer.Change(soaRecord.Retry * 1000, Timeout.Infinite);
+            }
+        }
+
+        private bool RefreshZone(NameServerAddress nameServer)
+        {
+            try
+            {
+                DnsClient client = new DnsClient(nameServer);
+                client.Timeout = REFRESH_TIMEOUT;
+                client.Retries = REFRESH_RETRIES;
+
+                DnsDatagram soaRequest = new DnsDatagram(0, false, DnsOpcode.StandardQuery, false, false, false, false, false, false, DnsResponseCode.NoError, new DnsQuestionRecord[] { new DnsQuestionRecord(_name, DnsResourceRecordType.SOA, DnsClass.IN) });
+                DnsDatagram soaResponse = client.Resolve(soaRequest);
+
+                if (soaResponse.RCODE != DnsResponseCode.NoError)
+                {
+                    LogManager log = _dnsServer.LogManager;
+                    if (log != null)
+                        log.Write("DNS Server received RCODE=" + soaResponse.RCODE.ToString() + " for '" + _name + "' secondary zone refresh from: " + nameServer.ToString());
+
+                    return false;
+                }
+
+                if (soaResponse.Answer.Count < 1)
+                {
+                    LogManager log = _dnsServer.LogManager;
+                    if (log != null)
+                        log.Write("DNS Server received an empty response for SOA query for '" + _name + "' secondary zone refresh from: " + nameServer.ToString());
+
+                    return false;
+                }
+
+                DnsSOARecord currentSoaRecord = _entries[DnsResourceRecordType.SOA][0].RDATA as DnsSOARecord;
+                DnsSOARecord receivedSoaRecord = soaResponse.Answer[0].RDATA as DnsSOARecord;
+
+                //compare using sequence space arithmetic
+                if (!currentSoaRecord.IsZoneUpdateAvailable(receivedSoaRecord))
+                {
+                    LogManager log = _dnsServer.LogManager;
+                    if (log != null)
+                        log.Write("DNS Server successfully refreshed '" + _name + "' secondary zone from: " + nameServer.ToString());
+
+                    return true;
+                }
+
+                //update available; do zone transfer
+                nameServer = new NameServerAddress(nameServer, DnsTransportProtocol.Tcp);
+                client = new DnsClient(nameServer);
+                client.Timeout = REFRESH_TIMEOUT;
+                client.Retries = REFRESH_RETRIES;
+
+                DnsDatagram axfrRequest = new DnsDatagram(0, false, DnsOpcode.StandardQuery, false, false, false, false, false, false, DnsResponseCode.NoError, new DnsQuestionRecord[] { new DnsQuestionRecord(_name, DnsResourceRecordType.AXFR, DnsClass.IN) });
+                DnsDatagram axfrResponse = client.Resolve(axfrRequest);
+
+                if (axfrResponse.RCODE != DnsResponseCode.NoError)
+                {
+                    LogManager log = _dnsServer.LogManager;
+                    if (log != null)
+                        log.Write("DNS Server received RCODE=" + axfrResponse.RCODE.ToString() + " for '" + _name + "' secondary zone refresh from: " + nameServer.ToString());
+
+                    return false;
+                }
+
+                if (axfrResponse.Answer.Count < 1)
+                {
+                    LogManager log = _dnsServer.LogManager;
+                    if (log != null)
+                        log.Write("DNS Server received an empty response for AXFR query for '" + _name + "' secondary zone from: " + nameServer.ToString());
+
+                    return false;
+                }
+
+                DnsSOARecord axfrSoaRecord = axfrResponse.Answer[0].RDATA as DnsSOARecord;
+                if (axfrSoaRecord == null)
+                {
+                    LogManager log = _dnsServer.LogManager;
+                    if (log != null)
+                        log.Write("DNS Server received invalid response for AXFR query for '" + _name + "' secondary zone from: " + nameServer.ToString());
+
+                    return false;
+                }
+
+                if (currentSoaRecord.IsZoneUpdateAvailable(axfrSoaRecord))
+                    _dnsServer.AuthZoneManager.SyncRecords(_name, axfrResponse.Answer);
+
+                {
+                    LogManager log = _dnsServer.LogManager;
+                    if (log != null)
+                        log.Write("DNS Server successfully refreshed '" + _name + "' secondary zone from: " + nameServer.ToString());
+                }
+
+                return true;
+            }
+            catch (Exception ex)
+            {
+                LogManager log = _dnsServer.LogManager;
+                if (log != null)
+                {
+                    log.Write("DNS Server failed to refresh '" + _name + "' secondary zone from: " + nameServer.ToString());
+                    log.Write(ex);
+                }
+
+                return false;
+            }
         }
 
         #endregion
 
         #region public
 
+        public void RefreshZone()
+        {
+            if (_disabled)
+                return;
+
+            _refreshTimer.Change(REFRESH_TIMER_INITIAL_INTERVAL, Timeout.Infinite);
+        }
+
         public override void SetRecords(DnsResourceRecordType type, IReadOnlyList<DnsResourceRecord> records)
         {
-            throw new InvalidOperationException("Cannot set records for secondary zone.");
+            throw new InvalidOperationException("Cannot set records in secondary zone.");
         }
 
         public override void AddRecord(DnsResourceRecord record)
         {
-            throw new InvalidOperationException("Cannot add record for secondary zone.");
+            throw new InvalidOperationException("Cannot add record in secondary zone.");
         }
 
         public override bool DeleteRecord(DnsResourceRecordType type, DnsResourceRecordData record)
         {
-            throw new InvalidOperationException("Cannot delete record for secondary zone.");
+            throw new InvalidOperationException("Cannot delete record in secondary zone.");
         }
 
         public override bool DeleteRecords(DnsResourceRecordType type)
         {
-            throw new InvalidOperationException("Cannot delete records for secondary zone.");
+            throw new InvalidOperationException("Cannot delete records in secondary zone.");
         }
 
         #endregion
+
+        #region properties
+
+        public DateTime LastRefreshed
+        { get { return _lastRefreshed; } }
+
+        #endregion
     }
 }