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SecondaryZone: implemented notify feature.

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This commit is contained in:
Shreyas Zare
2021-05-23 17:49:10 +05:30
parent fa1e20442f
commit dddb9c6114
1 changed files with 142 additions and 11 deletions
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153
DnsServerCore/Dns/Zones/SecondaryZone.cs
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@@ -20,6 +20,7 @@ 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 System.Threading.Tasks;
using TechnitiumLibrary.Net.Dns;
@@ -33,6 +34,13 @@ namespace DnsServerCore.Dns.Zones
DnsServer _dnsServer;
readonly Timer _notifyTimer;
const int NOTIFY_TIMER_INTERVAL = 10000;
readonly List<NameServerAddress> _notifyList;
const int NOTIFY_TIMEOUT = 10000;
const int NOTIFY_RETRIES = 5;
readonly object _refreshTimerLock = new object();
Timer _refreshTimer;
const int REFRESH_TIMER_INTERVAL = 5000;
@@ -48,20 +56,30 @@ namespace DnsServerCore.Dns.Zones
#region constructor
private SecondaryZone(string name)
: base(name)
{ }
public SecondaryZone(DnsServer dnsServer, AuthZoneInfo zoneInfo)
: base(zoneInfo.Name)
: base(zoneInfo)
{
_dnsServer = dnsServer;
_disabled = zoneInfo.Disabled;
_expiry = zoneInfo.Expiry;
_isExpired = DateTime.UtcNow > _expiry;
_refreshTimer = new Timer(RefreshTimerCallback, null, Timeout.Infinite, Timeout.Infinite);
_notifyTimer = new Timer(NotifyTimerCallback, null, Timeout.Infinite, Timeout.Infinite);
_notifyList = new List<NameServerAddress>();
}
private SecondaryZone(DnsServer dnsServer, string name)
: base(name)
{
_dnsServer = dnsServer;
_zoneTransfer = AuthZoneTransfer.Deny;
_notify = AuthZoneNotify.None;
_notifyTimer = new Timer(NotifyTimerCallback, null, Timeout.Infinite, Timeout.Infinite);
_notifyList = new List<NameServerAddress>();
}
#endregion
@@ -70,9 +88,7 @@ namespace DnsServerCore.Dns.Zones
public static async Task<SecondaryZone> CreateAsync(DnsServer dnsServer, string name, string primaryNameServerAddresses = null)
{
SecondaryZone secondaryZone = new SecondaryZone(name);
secondaryZone._dnsServer = dnsServer;
SecondaryZone secondaryZone = new SecondaryZone(dnsServer, name);
DnsQuestionRecord soaQuestion = new DnsQuestionRecord(name, DnsResourceRecordType.SOA, DnsClass.IN);
DnsDatagram soaResponse = null;
@@ -140,6 +156,104 @@ namespace DnsServerCore.Dns.Zones
#region private
private async void NotifyTimerCallback(object state)
{
try
{
switch (_notify)
{
case AuthZoneNotify.ZoneNameServers:
IReadOnlyList<NameServerAddress> secondaryNameServers = await GetSecondaryNameServerAddressesAsync(_dnsServer);
foreach (NameServerAddress secondaryNameServer in secondaryNameServers)
_ = NotifyNameServerAsync(secondaryNameServer);
break;
case AuthZoneNotify.SpecifiedNameServers:
IReadOnlyCollection<IPAddress> specifiedNameServers = _notifyNameServers;
if (specifiedNameServers is not null)
{
foreach (IPAddress specifiedNameServer in specifiedNameServers)
_ = NotifyNameServerAsync(new NameServerAddress(specifiedNameServer));
}
break;
default:
return;
}
}
catch (Exception ex)
{
LogManager log = _dnsServer.LogManager;
if (log != null)
log.Write(ex);
}
}
private async Task NotifyNameServerAsync(NameServerAddress nameServer)
{
//use notify list to prevent multiple threads from notifying the same name server
lock (_notifyList)
{
if (_notifyList.Contains(nameServer))
return; //already notifying the name server in another thread
_notifyList.Add(nameServer);
}
try
{
DnsClient client = new DnsClient(nameServer);
client.Proxy = _dnsServer.Proxy;
client.Timeout = NOTIFY_TIMEOUT;
client.Retries = NOTIFY_RETRIES;
DnsDatagram notifyRequest = new DnsDatagram(0, false, DnsOpcode.Notify, true, false, false, false, false, false, DnsResponseCode.NoError, new DnsQuestionRecord[] { new DnsQuestionRecord(_name, DnsResourceRecordType.SOA, DnsClass.IN) }, _entries[DnsResourceRecordType.SOA]);
DnsDatagram response = await client.ResolveAsync(notifyRequest);
switch (response.RCODE)
{
case DnsResponseCode.NoError:
case DnsResponseCode.NotImplemented:
{
//transaction complete
LogManager log = _dnsServer.LogManager;
if (log != null)
log.Write("DNS Server successfully notified name server for '" + _name + "' zone changes: " + nameServer.ToString());
}
break;
default:
{
//transaction failed
LogManager log = _dnsServer.LogManager;
if (log != null)
log.Write("DNS Server received RCODE=" + response.RCODE.ToString() + " from name server for '" + _name + "' zone notification: " + nameServer.ToString());
}
break;
}
}
catch (Exception ex)
{
LogManager log = _dnsServer.LogManager;
if (log != null)
{
log.Write("DNS Server failed to notify name server for '" + _name + "' zone changes: " + nameServer.ToString());
log.Write(ex);
}
}
finally
{
lock (_notifyList)
{
_notifyList.Remove(nameServer);
}
}
}
private async void RefreshTimerCallback(object state)
{
if (_disabled)
@@ -210,6 +324,9 @@ namespace DnsServerCore.Dns.Zones
}
DnsClient client = new DnsClient(primaryNameServers);
client.Proxy = _dnsServer.Proxy;
client.PreferIPv6 = _dnsServer.PreferIPv6;
client.Timeout = REFRESH_SOA_TIMEOUT;
client.Retries = REFRESH_RETRIES;
@@ -255,6 +372,9 @@ namespace DnsServerCore.Dns.Zones
primaryNameServers = tcpNameServers;
client = new DnsClient(primaryNameServers);
client.Proxy = _dnsServer.Proxy;
client.PreferIPv6 = _dnsServer.PreferIPv6;
client.Timeout = REFRESH_AXFR_TIMEOUT;
client.Retries = REFRESH_RETRIES;
@@ -293,6 +413,9 @@ namespace DnsServerCore.Dns.Zones
{
_dnsServer.AuthZoneManager.SyncRecords(_name, axfrResponse.Answer);
//trigger notify
TriggerNotify();
LogManager log = _dnsServer.LogManager;
if (log != null)
log.Write("DNS Server successfully refreshed '" + _name + "' secondary zone from: " + axfrResponse.Metadata.NameServerAddress.ToString());
@@ -333,7 +456,15 @@ namespace DnsServerCore.Dns.Zones
#region public
public void RefreshZone()
public void TriggerNotify()
{
if (_notify == AuthZoneNotify.None)
return;
_notifyTimer.Change(NOTIFY_TIMER_INTERVAL, Timeout.Infinite);
}
public void TriggerRefresh()
{
if (_disabled)
return;
@@ -397,7 +528,7 @@ namespace DnsServerCore.Dns.Zones
if (_disabled)
_refreshTimer.Change(Timeout.Infinite, Timeout.Infinite);
else
RefreshZone();
TriggerRefresh();
}
}
}