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https://github.com/fergalmoran/DnsServer.git
synced 2026-01-06 16:53:59 +00:00
StubZone: implemented zone refresh from primary server.
This commit is contained in:
Shreyas Zare
@@ -17,8 +17,11 @@ along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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using DnsServerCore.Dns.ResourceRecords;
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using System;
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using System.Collections.Generic;
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using System.Net;
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using System.Threading;
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using TechnitiumLibrary.Net.Dns;
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using TechnitiumLibrary.Net.Dns.ResourceRecords;
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@@ -26,40 +29,315 @@ namespace DnsServerCore.Dns.Zones
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{
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public sealed class StubZone : AuthZone
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{
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#region variables
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readonly DnsServer _dnsServer;
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readonly Timer _refreshTimer;
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const int REFRESH_TIMER_INITIAL_INTERVAL = 30000;
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const int REFRESH_TIMEOUT = 60000;
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const int REFRESH_RETRIES = 5;
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#endregion
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#region constructor
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public StubZone(string name, DnsSOARecord soa)
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: base(name, soa)
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{ }
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public StubZone(string name, bool disabled)
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: base(name)
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public StubZone(DnsServer dnsServer, AuthZoneInfo zoneInfo)
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: base(zoneInfo.Name)
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{
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_disabled = disabled;
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_dnsServer = dnsServer;
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_disabled = zoneInfo.Disabled;
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_refreshTimer = new Timer(RefreshTimerCallback, null, Timeout.Infinite, Timeout.Infinite);
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}
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public StubZone(DnsServer dnsServer, string name, DnsSOARecord soa)
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: base(name, soa)
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{
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_dnsServer = dnsServer;
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_refreshTimer = new Timer(RefreshTimerCallback, null, Timeout.Infinite, Timeout.Infinite);
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}
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#endregion
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#region IDisposable
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bool _disposed;
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protected override void Dispose(bool disposing)
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{
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if (_disposed)
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return;
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if (disposing)
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{
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if (_refreshTimer != null)
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_refreshTimer.Dispose();
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}
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_disposed = true;
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}
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#endregion
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#region private
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private void RefreshTimerCallback(object state)
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{
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if (_disabled)
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return;
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DnsResourceRecord record = _entries[DnsResourceRecordType.SOA][0];
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DnsSOARecord soaRecord = record.RDATA as DnsSOARecord;
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try
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{
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string nsDomain = soaRecord.MasterNameServer;
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List<NameServerAddress> nameServers = new List<NameServerAddress>();
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IReadOnlyList<DnsResourceRecord> glueRecords = record.GetGlueRecords();
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if (glueRecords.Count > 0)
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{
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foreach (DnsResourceRecord glueRecord in glueRecords)
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{
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switch (glueRecord.Type)
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{
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case DnsResourceRecordType.A:
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nameServers.Add(new NameServerAddress(nsDomain, (glueRecord.RDATA as DnsARecord).Address));
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break;
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case DnsResourceRecordType.AAAA:
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if (_dnsServer.PreferIPv6)
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nameServers.Add(new NameServerAddress(nsDomain, (glueRecord.RDATA as DnsAAAARecord).Address));
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break;
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}
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}
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}
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else
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{
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//resolve addresses
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DnsDatagram response = _dnsServer.DirectQuery(new DnsQuestionRecord(nsDomain, DnsResourceRecordType.A, DnsClass.IN));
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if (response != null)
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{
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IReadOnlyList<IPAddress> addresses = DnsClient.ParseResponseA(response);
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foreach (IPAddress address in addresses)
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nameServers.Add(new NameServerAddress(nsDomain, address));
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}
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if (_dnsServer.PreferIPv6)
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{
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response = _dnsServer.DirectQuery(new DnsQuestionRecord(nsDomain, DnsResourceRecordType.AAAA, DnsClass.IN));
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if (response != null)
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{
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IReadOnlyList<IPAddress> addresses = DnsClient.ParseResponseAAAA(response);
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foreach (IPAddress address in addresses)
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nameServers.Add(new NameServerAddress(nsDomain, address));
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}
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}
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}
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//refresh zone
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foreach (NameServerAddress nameServer in nameServers)
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{
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if (RefreshZone(nameServer))
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{
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//zone refreshed; set timer for refresh
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DnsSOARecord latestSoaRecord = _entries[DnsResourceRecordType.SOA][0].RDATA as DnsSOARecord;
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_refreshTimer.Change(latestSoaRecord.Refresh * 1000, Timeout.Infinite);
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_dnsServer.AuthZoneManager.SaveZoneFile(_name);
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return;
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}
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}
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//no response from any of the name servers; set timer for retry
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_refreshTimer.Change(soaRecord.Retry * 1000, Timeout.Infinite);
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}
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catch (Exception ex)
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{
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LogManager log = _dnsServer.LogManager;
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if (log != null)
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log.Write(ex);
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//set timer for retry
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_refreshTimer.Change(soaRecord.Retry * 1000, Timeout.Infinite);
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}
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}
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private bool RefreshZone(NameServerAddress nameServer)
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{
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try
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{
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DnsClient client = new DnsClient(nameServer);
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client.Timeout = REFRESH_TIMEOUT;
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client.Retries = REFRESH_RETRIES;
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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) });
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DnsDatagram soaResponse = client.Resolve(soaRequest);
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if (soaResponse.RCODE != DnsResponseCode.NoError)
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{
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LogManager log = _dnsServer.LogManager;
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if (log != null)
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log.Write("DNS Server received RCODE=" + soaResponse.RCODE.ToString() + " for '" + _name + "' stub zone refresh from: " + nameServer.ToString());
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return false;
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}
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if (soaResponse.Answer.Count < 1)
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{
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LogManager log = _dnsServer.LogManager;
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if (log != null)
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log.Write("DNS Server received an empty response for SOA query for '" + _name + "' stub zone refresh from: " + nameServer.ToString());
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return false;
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}
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DnsSOARecord currentSoaRecord = _entries[DnsResourceRecordType.SOA][0].RDATA as DnsSOARecord;
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DnsSOARecord receivedSoaRecord = soaResponse.Answer[0].RDATA as DnsSOARecord;
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//compare using sequence space arithmetic
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if (!currentSoaRecord.IsZoneUpdateAvailable(receivedSoaRecord))
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{
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LogManager log = _dnsServer.LogManager;
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if (log != null)
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log.Write("DNS Server successfully refreshed '" + _name + "' stub zone from: " + nameServer.ToString());
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return true;
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}
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//update available; do zone sync
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nameServer = new NameServerAddress(nameServer, DnsTransportProtocol.Tcp);
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client = new DnsClient(nameServer);
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client.Timeout = REFRESH_TIMEOUT;
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client.Retries = REFRESH_RETRIES;
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DnsDatagram nsRequest = new DnsDatagram(0, false, DnsOpcode.StandardQuery, false, false, false, false, false, false, DnsResponseCode.NoError, new DnsQuestionRecord[] { new DnsQuestionRecord(_name, DnsResourceRecordType.NS, DnsClass.IN) });
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DnsDatagram nsResponse = client.Resolve(nsRequest);
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if (nsResponse.RCODE != DnsResponseCode.NoError)
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{
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LogManager log = _dnsServer.LogManager;
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if (log != null)
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log.Write("DNS Server received RCODE=" + nsResponse.RCODE.ToString() + " for '" + _name + "' stub zone refresh from: " + nameServer.ToString());
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return false;
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}
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if (nsResponse.Answer.Count < 1)
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{
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LogManager log = _dnsServer.LogManager;
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if (log != null)
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log.Write("DNS Server received an empty response for NS query for '" + _name + "' stub zone from: " + nameServer.ToString());
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return false;
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}
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List<DnsResourceRecord> allRecords = new List<DnsResourceRecord>();
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allRecords.AddRange(nsResponse.Answer);
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allRecords.AddRange(soaResponse.Answer); //to sync latest SOA record
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_dnsServer.AuthZoneManager.SyncRecords(_name, allRecords, nsResponse.Additional, true);
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{
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LogManager log = _dnsServer.LogManager;
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if (log != null)
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log.Write("DNS Server successfully refreshed '" + _name + "' stub zone from: " + nameServer.ToString());
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}
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return true;
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}
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catch (Exception ex)
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{
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LogManager log = _dnsServer.LogManager;
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if (log != null)
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{
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log.Write("DNS Server failed to refresh '" + _name + "' stub zone from: " + nameServer.ToString());
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log.Write(ex);
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}
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return false;
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}
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}
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#endregion
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#region public
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public void RefreshZone()
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{
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if (_disabled)
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return;
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_refreshTimer.Change(REFRESH_TIMER_INITIAL_INTERVAL, Timeout.Infinite);
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}
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public override void SetRecords(DnsResourceRecordType type, IReadOnlyList<DnsResourceRecord> records)
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{
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throw new InvalidOperationException("Cannot set records for stub zone.");
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switch (type)
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{
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case DnsResourceRecordType.CNAME:
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throw new InvalidOperationException("Cannot set CNAME record to zone root.");
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case DnsResourceRecordType.NS:
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throw new InvalidOperationException("Cannot set NS records at stub zone root.");
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case DnsResourceRecordType.SOA:
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throw new InvalidOperationException("Cannot set SOA record in stub zone.");
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default:
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base.SetRecords(type, records);
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break;
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}
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}
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public override void AddRecord(DnsResourceRecord record)
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{
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throw new InvalidOperationException("Cannot add record for stub zone.");
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}
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switch (record.Type)
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{
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case DnsResourceRecordType.NS:
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throw new InvalidOperationException("Cannot add NS record at stub zone root.");
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public override bool DeleteRecord(DnsResourceRecordType type, DnsResourceRecordData record)
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{
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throw new InvalidOperationException("Cannot delete record for stub zone.");
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default:
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base.AddRecord(record);
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break;
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}
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}
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public override bool DeleteRecords(DnsResourceRecordType type)
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{
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throw new InvalidOperationException("Cannot delete records for stub zone.");
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switch (type)
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{
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case DnsResourceRecordType.NS:
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throw new InvalidOperationException("Cannot delete NS records in stub zone root.");
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case DnsResourceRecordType.SOA:
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throw new InvalidOperationException("Cannot delete SOA record.");
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default:
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return base.DeleteRecords(type);
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}
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}
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public override bool DeleteRecord(DnsResourceRecordType type, DnsResourceRecordData record)
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{
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switch (type)
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{
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case DnsResourceRecordType.NS:
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throw new InvalidOperationException("Cannot delete NS record in stub zone root.");
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case DnsResourceRecordType.SOA:
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throw new InvalidOperationException("Cannot delete SOA record.");
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default:
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return base.DeleteRecord(type, record);
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}
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}
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#endregion
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