mirror of
https://github.com/fergalmoran/DnsServer.git
synced 2026-01-06 16:53:59 +00:00
400 lines
15 KiB
C#
400 lines
15 KiB
C#
/*
|
|
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 DnsServerCore.Dns.ResourceRecords;
|
|
using System;
|
|
using System.Collections.Generic;
|
|
using System.Threading;
|
|
using TechnitiumLibrary.Net.Dns;
|
|
using TechnitiumLibrary.Net.Dns.ResourceRecords;
|
|
|
|
namespace DnsServerCore.Dns.Zones
|
|
{
|
|
class SecondaryZone : AuthZone
|
|
{
|
|
#region variables
|
|
|
|
readonly DnsServer _dnsServer;
|
|
|
|
readonly object _refreshTimerLock = new object();
|
|
Timer _refreshTimer;
|
|
const int REFRESH_TIMER_INTERVAL = 5000;
|
|
|
|
const int REFRESH_SOA_TIMEOUT = 10000;
|
|
const int REFRESH_AXFR_TIMEOUT = 300000;
|
|
const int REFRESH_RETRIES = 5;
|
|
|
|
DateTime _expiry;
|
|
bool _isExpired;
|
|
|
|
#endregion
|
|
|
|
#region constructor
|
|
|
|
public SecondaryZone(DnsServer dnsServer, AuthZoneInfo zoneInfo)
|
|
: base(zoneInfo.Name)
|
|
{
|
|
_dnsServer = dnsServer;
|
|
|
|
_disabled = zoneInfo.Disabled;
|
|
_expiry = zoneInfo.Expiry;
|
|
|
|
_isExpired = DateTime.UtcNow > _expiry;
|
|
_refreshTimer = new Timer(RefreshTimerCallback, null, Timeout.Infinite, Timeout.Infinite);
|
|
}
|
|
|
|
public SecondaryZone(DnsServer dnsServer, string name, string primaryNameServerAddresses = null)
|
|
: base(name)
|
|
{
|
|
_dnsServer = dnsServer;
|
|
|
|
DnsQuestionRecord soaQuestion = new DnsQuestionRecord(name, DnsResourceRecordType.SOA, DnsClass.IN);
|
|
DnsDatagram soaResponse = null;
|
|
|
|
if (primaryNameServerAddresses == null)
|
|
{
|
|
soaResponse = _dnsServer.DirectQuery(soaQuestion);
|
|
}
|
|
else
|
|
{
|
|
DnsClient dnsClient = new DnsClient(primaryNameServerAddresses);
|
|
|
|
dnsClient.Proxy = _dnsServer.Proxy;
|
|
dnsClient.PreferIPv6 = _dnsServer.PreferIPv6;
|
|
dnsClient.Retries = _dnsServer.Retries;
|
|
dnsClient.Timeout = _dnsServer.Timeout;
|
|
|
|
soaResponse = dnsClient.Resolve(soaQuestion);
|
|
}
|
|
|
|
if ((soaResponse == null) || (soaResponse.Answer.Count == 0) || (soaResponse.Answer[0].Type != DnsResourceRecordType.SOA))
|
|
throw new DnsServerException("DNS Server failed to find SOA record for: " + name);
|
|
|
|
DnsSOARecord receivedSoa = soaResponse.Answer[0].RDATA as DnsSOARecord;
|
|
|
|
DnsSOARecord soa = new DnsSOARecord(receivedSoa.PrimaryNameServer, receivedSoa.ResponsiblePerson, receivedSoa.Serial - 1, receivedSoa.Refresh, receivedSoa.Retry, receivedSoa.Expire, receivedSoa.Minimum);
|
|
DnsResourceRecord[] soaRR = new DnsResourceRecord[] { new DnsResourceRecord(_name, DnsResourceRecordType.SOA, DnsClass.IN, soa.Refresh, soa) };
|
|
|
|
if (!string.IsNullOrEmpty(primaryNameServerAddresses))
|
|
soaRR[0].SetGlueRecords(primaryNameServerAddresses);
|
|
|
|
_entries[DnsResourceRecordType.SOA] = soaRR;
|
|
|
|
_isExpired = true; //new secondary zone is considered expired till it refreshes
|
|
_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)
|
|
{
|
|
lock (_refreshTimerLock)
|
|
{
|
|
if (_refreshTimer != null)
|
|
{
|
|
_refreshTimer.Dispose();
|
|
_refreshTimer = null;
|
|
}
|
|
}
|
|
}
|
|
|
|
_disposed = true;
|
|
}
|
|
|
|
#endregion
|
|
|
|
#region private
|
|
|
|
private void RefreshTimerCallback(object state)
|
|
{
|
|
if (_disabled)
|
|
return;
|
|
|
|
try
|
|
{
|
|
_isExpired = DateTime.UtcNow > _expiry;
|
|
|
|
//get primary name server addresses
|
|
IReadOnlyList<NameServerAddress> primaryNameServers = GetPrimaryNameServerAddresses(_dnsServer);
|
|
|
|
if (primaryNameServers.Count == 0)
|
|
{
|
|
LogManager log = _dnsServer.LogManager;
|
|
if (log != null)
|
|
log.Write("DNS Server could not find primary name server IP addresses for secondary zone: " + _name);
|
|
|
|
//set timer for retry
|
|
DnsSOARecord soa1 = _entries[DnsResourceRecordType.SOA][0].RDATA as DnsSOARecord;
|
|
_refreshTimer.Change(soa1.Retry * 1000, Timeout.Infinite);
|
|
return;
|
|
}
|
|
|
|
//refresh zone
|
|
if (RefreshZone(primaryNameServers))
|
|
{
|
|
//zone refreshed; set timer for refresh
|
|
DnsSOARecord latestSoa = _entries[DnsResourceRecordType.SOA][0].RDATA as DnsSOARecord;
|
|
_refreshTimer.Change(latestSoa.Refresh * 1000, Timeout.Infinite);
|
|
|
|
_expiry = DateTime.UtcNow.AddSeconds(latestSoa.Expire);
|
|
_isExpired = false;
|
|
_dnsServer.AuthZoneManager.SaveZoneFile(_name);
|
|
return;
|
|
}
|
|
|
|
//no response from any of the name servers; set timer for retry
|
|
DnsSOARecord soa = _entries[DnsResourceRecordType.SOA][0].RDATA as DnsSOARecord;
|
|
_refreshTimer.Change(soa.Retry * 1000, Timeout.Infinite);
|
|
}
|
|
catch (Exception ex)
|
|
{
|
|
LogManager log = _dnsServer.LogManager;
|
|
if (log != null)
|
|
log.Write(ex);
|
|
|
|
//set timer for retry
|
|
lock (_refreshTimerLock)
|
|
{
|
|
if (_refreshTimer != null)
|
|
{
|
|
DnsSOARecord soa = _entries[DnsResourceRecordType.SOA][0].RDATA as DnsSOARecord;
|
|
_refreshTimer.Change(soa.Retry * 1000, Timeout.Infinite);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
private bool RefreshZone(IReadOnlyList<NameServerAddress> primaryNameServers)
|
|
{
|
|
try
|
|
{
|
|
{
|
|
LogManager log = _dnsServer.LogManager;
|
|
if (log != null)
|
|
log.Write("DNS Server has started zone refresh for secondary zone: " + _name);
|
|
}
|
|
|
|
DnsClient client = new DnsClient(primaryNameServers);
|
|
client.Timeout = REFRESH_SOA_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: " + soaResponse.Metadata.NameServerAddress.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: " + soaResponse.Metadata.NameServerAddress.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 checked for update to '" + _name + "' secondary zone from: " + soaResponse.Metadata.NameServerAddress.ToString());
|
|
|
|
return true;
|
|
}
|
|
|
|
//update available; do zone transfer with TCP transport
|
|
List<NameServerAddress> tcpNameServers = new List<NameServerAddress>();
|
|
|
|
foreach (NameServerAddress nameServer in primaryNameServers)
|
|
tcpNameServers.Add(new NameServerAddress(nameServer, DnsTransportProtocol.Tcp));
|
|
|
|
primaryNameServers = tcpNameServers;
|
|
client = new DnsClient(primaryNameServers);
|
|
client.Timeout = REFRESH_AXFR_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: " + axfrResponse.Metadata.NameServerAddress.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: " + axfrResponse.Metadata.NameServerAddress.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: " + axfrResponse.Metadata.NameServerAddress.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: " + axfrResponse.Metadata.NameServerAddress.ToString());
|
|
}
|
|
else
|
|
{
|
|
LogManager log = _dnsServer.LogManager;
|
|
if (log != null)
|
|
log.Write("DNS Server successfully checked for update to '" + _name + "' secondary zone from: " + soaResponse.Metadata.NameServerAddress.ToString());
|
|
}
|
|
|
|
return true;
|
|
}
|
|
catch (Exception ex)
|
|
{
|
|
LogManager log = _dnsServer.LogManager;
|
|
if (log != null)
|
|
{
|
|
string strNameServers = null;
|
|
|
|
foreach (NameServerAddress nameServer in primaryNameServers)
|
|
{
|
|
if (strNameServers == null)
|
|
strNameServers = nameServer.ToString();
|
|
else
|
|
strNameServers += ", " + nameServer.ToString();
|
|
}
|
|
|
|
log.Write("DNS Server failed to refresh '" + _name + "' secondary zone from: " + strNameServers);
|
|
log.Write(ex);
|
|
}
|
|
|
|
return false;
|
|
}
|
|
}
|
|
|
|
#endregion
|
|
|
|
#region public
|
|
|
|
public void RefreshZone()
|
|
{
|
|
if (_disabled)
|
|
return;
|
|
|
|
_refreshTimer.Change(REFRESH_TIMER_INTERVAL, Timeout.Infinite);
|
|
}
|
|
|
|
public override void SetRecords(DnsResourceRecordType type, IReadOnlyList<DnsResourceRecord> records)
|
|
{
|
|
switch (type)
|
|
{
|
|
case DnsResourceRecordType.SOA:
|
|
if ((records.Count != 1) || !records[0].Name.Equals(_name, StringComparison.OrdinalIgnoreCase))
|
|
throw new InvalidOperationException("Invalid SOA record.");
|
|
|
|
_entries[DnsResourceRecordType.SOA][0].SetGlueRecords(records.GetGlueRecords());
|
|
break;
|
|
|
|
default:
|
|
throw new InvalidOperationException("Cannot set records in secondary zone.");
|
|
}
|
|
}
|
|
|
|
public override void AddRecord(DnsResourceRecord record)
|
|
{
|
|
throw new InvalidOperationException("Cannot add record in secondary zone.");
|
|
}
|
|
|
|
public override bool DeleteRecord(DnsResourceRecordType type, DnsResourceRecordData record)
|
|
{
|
|
throw new InvalidOperationException("Cannot delete record in secondary zone.");
|
|
}
|
|
|
|
public override bool DeleteRecords(DnsResourceRecordType type)
|
|
{
|
|
throw new InvalidOperationException("Cannot delete records in secondary zone.");
|
|
}
|
|
|
|
#endregion
|
|
|
|
#region properties
|
|
|
|
public DateTime Expiry
|
|
{ get { return _expiry; } }
|
|
|
|
public bool IsExpired
|
|
{ get { return _isExpired; } }
|
|
|
|
public override bool Disabled
|
|
{
|
|
get { return _disabled; }
|
|
set
|
|
{
|
|
if (_disabled != value)
|
|
{
|
|
_disabled = value;
|
|
|
|
if (_disabled)
|
|
_refreshTimer.Change(Timeout.Infinite, Timeout.Infinite);
|
|
else
|
|
RefreshZone();
|
|
}
|
|
}
|
|
}
|
|
|
|
public override bool IsActive
|
|
{
|
|
get { return !_disabled && !_isExpired; }
|
|
}
|
|
|
|
#endregion
|
|
}
|
|
}
|