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SecondaryZone: Disposing notify timer. Added ResetRefreshTimer() method to safely reset refresh timer. Setting dns client concurrency to 1 for refresh. Implemented IXFR failover to switch to AXFR.

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This commit is contained in:
Shreyas Zare
2021-07-18 15:43:09 +05:30
parent a0edc08104
commit f297763283
1 changed files with 95 additions and 78 deletions
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173
DnsServerCore/Dns/Zones/SecondaryZone.cs
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@@ -153,6 +153,9 @@ namespace DnsServerCore.Dns.Zones
if (disposing)
{
if (_notifyTimer is not null)
_notifyTimer.Dispose();
lock (_refreshTimerLock)
{
if (_refreshTimer != null)
@@ -292,7 +295,7 @@ namespace DnsServerCore.Dns.Zones
//set timer for retry
DnsSOARecord soa1 = _entries[DnsResourceRecordType.SOA][0].RDATA as DnsSOARecord;
_refreshTimer.Change(soa1.Retry * 1000, Timeout.Infinite);
ResetRefreshTimer(soa1.Retry * 1000);
return;
}
@@ -301,7 +304,7 @@ namespace DnsServerCore.Dns.Zones
{
//zone refreshed; set timer for refresh
DnsSOARecord latestSoa = _entries[DnsResourceRecordType.SOA][0].RDATA as DnsSOARecord;
_refreshTimer.Change(latestSoa.Refresh * 1000, Timeout.Infinite);
ResetRefreshTimer(latestSoa.Refresh * 1000);
_expiry = DateTime.UtcNow.AddSeconds(latestSoa.Expire);
_isExpired = false;
@@ -312,7 +315,7 @@ namespace DnsServerCore.Dns.Zones
//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);
ResetRefreshTimer(soa.Retry * 1000);
}
catch (Exception ex)
{
@@ -321,14 +324,8 @@ namespace DnsServerCore.Dns.Zones
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);
}
}
DnsSOARecord soa = _entries[DnsResourceRecordType.SOA][0].RDATA as DnsSOARecord;
ResetRefreshTimer(soa.Retry * 1000);
}
finally
{
@@ -336,6 +333,15 @@ namespace DnsServerCore.Dns.Zones
}
}
private void ResetRefreshTimer(long dueTime)
{
lock (_refreshTimerLock)
{
if (_refreshTimer != null)
_refreshTimer.Change(dueTime, Timeout.Infinite);
}
}
private async Task<bool> RefreshZoneAsync(IReadOnlyList<NameServerAddress> primaryNameServers)
{
try
@@ -352,6 +358,7 @@ namespace DnsServerCore.Dns.Zones
client.PreferIPv6 = _dnsServer.PreferIPv6;
client.Timeout = REFRESH_SOA_TIMEOUT;
client.Retries = REFRESH_RETRIES;
client.Concurrency = 1;
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 = await client.ResolveAsync(soaRequest);
@@ -403,84 +410,94 @@ namespace DnsServerCore.Dns.Zones
client.PreferIPv6 = _dnsServer.PreferIPv6;
client.Timeout = REFRESH_XFR_TIMEOUT;
client.Retries = REFRESH_RETRIES;
client.Concurrency = 1;
bool doIXFR = !_isExpired && !_resync;
DnsQuestionRecord xfrQuestion;
IReadOnlyList<DnsResourceRecord> xfrAuthority;
if (doIXFR)
while (true)
{
xfrQuestion = new DnsQuestionRecord(_name, DnsResourceRecordType.IXFR, DnsClass.IN);
xfrAuthority = new DnsResourceRecord[] { currentSoaRecord };
}
else
{
xfrQuestion = new DnsQuestionRecord(_name, DnsResourceRecordType.AXFR, DnsClass.IN);
xfrAuthority = null;
}
DnsQuestionRecord xfrQuestion;
IReadOnlyList<DnsResourceRecord> xfrAuthority;
DnsDatagram xfrRequest = new DnsDatagram(0, false, DnsOpcode.StandardQuery, false, false, false, false, false, false, DnsResponseCode.NoError, new DnsQuestionRecord[] { xfrQuestion }, null, xfrAuthority);
DnsDatagram xfrResponse = await client.ResolveAsync(xfrRequest);
if (xfrResponse.RCODE != DnsResponseCode.NoError)
{
LogManager log = _dnsServer.LogManager;
if (log != null)
log.Write("DNS Server received RCODE=" + xfrResponse.RCODE.ToString() + " for '" + _name + "' secondary zone transfer from: " + xfrResponse.Metadata.NameServerAddress.ToString());
return false;
}
if (xfrResponse.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: " + xfrResponse.Metadata.NameServerAddress.ToString());
return false;
}
if (!_name.Equals(xfrResponse.Answer[0].Name, StringComparison.OrdinalIgnoreCase) || (xfrResponse.Answer[0].Type != DnsResourceRecordType.SOA) || (xfrResponse.Answer[0].RDATA is not DnsSOARecord xfrSoa))
{
LogManager log = _dnsServer.LogManager;
if (log != null)
log.Write("DNS Server received invalid response for AXFR query for '" + _name + "' secondary zone from: " + xfrResponse.Metadata.NameServerAddress.ToString());
return false;
}
if (_resync || currentSoa.IsZoneUpdateAvailable(xfrSoa))
{
if (doIXFR)
{
IReadOnlyList<DnsResourceRecord> historyRecords = _dnsServer.AuthZoneManager.SyncIncrementalZoneTransferRecords(_name, xfrResponse.Answer);
if (historyRecords.Count > 0)
CommitHistory(historyRecords);
else
ClearHistory(); //AXFR response was received
xfrQuestion = new DnsQuestionRecord(_name, DnsResourceRecordType.IXFR, DnsClass.IN);
xfrAuthority = new DnsResourceRecord[] { currentSoaRecord };
}
else
{
_dnsServer.AuthZoneManager.SyncZoneTransferRecords(_name, xfrResponse.Answer);
ClearHistory();
xfrQuestion = new DnsQuestionRecord(_name, DnsResourceRecordType.AXFR, DnsClass.IN);
xfrAuthority = null;
}
//trigger notify
TriggerNotify();
DnsDatagram xfrRequest = new DnsDatagram(0, false, DnsOpcode.StandardQuery, false, false, false, false, false, false, DnsResponseCode.NoError, new DnsQuestionRecord[] { xfrQuestion }, null, xfrAuthority);
DnsDatagram xfrResponse = await client.ResolveAsync(xfrRequest);
LogManager log = _dnsServer.LogManager;
if (log != null)
log.Write("DNS Server successfully refreshed '" + _name + "' secondary zone from: " + xfrResponse.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());
}
if (doIXFR && (xfrResponse.RCODE == DnsResponseCode.NotImplemented))
{
doIXFR = false;
continue;
}
return true;
if (xfrResponse.RCODE != DnsResponseCode.NoError)
{
LogManager log = _dnsServer.LogManager;
if (log != null)
log.Write("DNS Server received RCODE=" + xfrResponse.RCODE.ToString() + " for '" + _name + "' secondary zone transfer from: " + xfrResponse.Metadata.NameServerAddress.ToString());
return false;
}
if (xfrResponse.Answer.Count < 1)
{
LogManager log = _dnsServer.LogManager;
if (log != null)
log.Write("DNS Server received an empty response for zone transfer query for '" + _name + "' secondary zone from: " + xfrResponse.Metadata.NameServerAddress.ToString());
return false;
}
if (!_name.Equals(xfrResponse.Answer[0].Name, StringComparison.OrdinalIgnoreCase) || (xfrResponse.Answer[0].Type != DnsResourceRecordType.SOA) || (xfrResponse.Answer[0].RDATA is not DnsSOARecord xfrSoa))
{
LogManager log = _dnsServer.LogManager;
if (log != null)
log.Write("DNS Server received invalid response for zone transfer query for '" + _name + "' secondary zone from: " + xfrResponse.Metadata.NameServerAddress.ToString());
return false;
}
if (_resync || currentSoa.IsZoneUpdateAvailable(xfrSoa))
{
if (doIXFR)
{
IReadOnlyList<DnsResourceRecord> historyRecords = _dnsServer.AuthZoneManager.SyncIncrementalZoneTransferRecords(_name, xfrResponse.Answer);
if (historyRecords.Count > 0)
CommitHistory(historyRecords);
else
ClearHistory(); //AXFR response was received
}
else
{
_dnsServer.AuthZoneManager.SyncZoneTransferRecords(_name, xfrResponse.Answer);
ClearHistory();
}
//trigger notify
TriggerNotify();
LogManager log = _dnsServer.LogManager;
if (log != null)
log.Write("DNS Server successfully refreshed '" + _name + "' secondary zone from: " + xfrResponse.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)
{
@@ -553,7 +570,7 @@ namespace DnsServerCore.Dns.Zones
if (_refreshTimerTriggered)
return;
_refreshTimer.Change(REFRESH_TIMER_INTERVAL, Timeout.Infinite);
ResetRefreshTimer(REFRESH_TIMER_INTERVAL);
_refreshTimerTriggered = true;
}
@@ -564,7 +581,7 @@ namespace DnsServerCore.Dns.Zones
_resync = true;
_refreshTimer.Change(REFRESH_TIMER_INTERVAL, Timeout.Infinite);
ResetRefreshTimer(REFRESH_TIMER_INTERVAL);
_refreshTimerTriggered = true;
}
@@ -636,7 +653,7 @@ namespace DnsServerCore.Dns.Zones
_disabled = value;
if (_disabled)
_refreshTimer.Change(Timeout.Infinite, Timeout.Infinite);
ResetRefreshTimer(Timeout.Infinite);
else
TriggerRefresh();
}