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Zone: code optimization done to init a zone's ConcurrentDictionary objects only when required with concurrency set to 1 to minimize memory usage.

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This commit is contained in:
Shreyas Zare
2020-02-29 17:55:50 +05:30
parent 176f099d34
commit 1ae7d4ef3c
1 changed files with 70 additions and 29 deletions
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99
DnsServerCore/Dns/Zone.cs
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@@ -47,8 +47,8 @@ namespace DnsServerCore.Dns
bool _disabled;
bool _internal;
readonly ConcurrentDictionary<string, Zone> _zones = new ConcurrentDictionary<string, Zone>();
readonly ConcurrentDictionary<DnsResourceRecordType, DnsResourceRecord[]> _entries = new ConcurrentDictionary<DnsResourceRecordType, DnsResourceRecord[]>();
ConcurrentDictionary<string, Zone> _zones;
ConcurrentDictionary<DnsResourceRecordType, DnsResourceRecord[]> _entries;
string _serverDomain;
@@ -124,6 +124,9 @@ namespace DnsServerCore.Dns
{
string nextZoneLabel = path[i];
if (currentZone._zones == null)
currentZone._zones = new ConcurrentDictionary<string, Zone>(1, 5);
Zone nextZone = currentZone._zones.GetOrAdd(nextZoneLabel, delegate (string key)
{
return new Zone(currentZone, nextZoneLabel);
@@ -140,7 +143,7 @@ namespace DnsServerCore.Dns
Zone currentZone = rootZone;
Zone authoritativeZone = null;
if (authoritative && currentZone._entries.ContainsKey(DnsResourceRecordType.SOA))
if (authoritative && (currentZone._entries != null) && currentZone._entries.ContainsKey(DnsResourceRecordType.SOA))
authoritativeZone = currentZone;
string[] path = ConvertDomainToPath(domain);
@@ -149,7 +152,7 @@ namespace DnsServerCore.Dns
{
string nextZoneLabel = path[i];
if (currentZone._zones.TryGetValue(nextZoneLabel, out Zone nextZone))
if ((currentZone._zones != null) && currentZone._zones.TryGetValue(nextZoneLabel, out Zone nextZone))
{
currentZone = nextZone;
}
@@ -161,7 +164,7 @@ namespace DnsServerCore.Dns
return null;
}
if (authoritative && currentZone._entries.ContainsKey(DnsResourceRecordType.SOA))
if (authoritative && (currentZone._entries != null) && currentZone._entries.ContainsKey(DnsResourceRecordType.SOA))
authoritativeZone = currentZone;
}
@@ -180,7 +183,7 @@ namespace DnsServerCore.Dns
if (!currentZone._authoritativeZone && (currentZone._zoneName.Equals("root-servers.net", StringComparison.OrdinalIgnoreCase)))
return false; //cannot delete root-servers.net
currentZone._entries.Clear();
currentZone._entries = null;
DeleteSubZones(currentZone, deleteSubZones);
DeleteEmptyParentZones(currentZone);
@@ -192,7 +195,7 @@ namespace DnsServerCore.Dns
{
if (currentZone._authoritativeZone)
{
if (!deleteSubZones && currentZone._entries.ContainsKey(DnsResourceRecordType.SOA))
if (!deleteSubZones && (currentZone._entries != null) && currentZone._entries.ContainsKey(DnsResourceRecordType.SOA))
return false; //this is a zone so return false
}
else
@@ -202,7 +205,10 @@ namespace DnsServerCore.Dns
return false; //cannot delete root-servers.net
}
currentZone._entries.Clear();
currentZone._entries = null;
if (currentZone._zones == null)
return true;
List<Zone> subDomainsToDelete = new List<Zone>();
@@ -215,14 +221,20 @@ namespace DnsServerCore.Dns
foreach (Zone subDomain in subDomainsToDelete)
currentZone._zones.TryRemove(subDomain._zoneLabel, out _);
return (currentZone._zones.Count == 0);
if (currentZone._zones.Count == 0)
{
currentZone._zones = null;
return true;
}
return false;
}
private static void DeleteEmptyParentZones(Zone currentZone)
{
while (currentZone._parentZone != null)
{
if ((currentZone._entries.Count > 0) || (currentZone._zones.Count > 0))
if (((currentZone._entries != null) && (currentZone._entries.Count > 0)) || ((currentZone._zones != null) && (currentZone._zones.Count > 0)))
break;
currentZone._parentZone._zones.TryRemove(currentZone._zoneLabel, out _);
@@ -234,6 +246,7 @@ namespace DnsServerCore.Dns
private static void RemoveExpiredCachedRecords(Zone currentZone)
{
//remove expired entries in current zone
if (currentZone._entries != null)
{
List<KeyValuePair<DnsResourceRecordType, DnsResourceRecord[]>> updateEntries = null;
@@ -283,6 +296,7 @@ namespace DnsServerCore.Dns
}
//remove expired entries in sub zones
if (currentZone._zones != null)
{
List<string> subZonesToRemove = null;
@@ -290,7 +304,7 @@ namespace DnsServerCore.Dns
{
RemoveExpiredCachedRecords(zone.Value);
if ((zone.Value._zones.Count == 0) && (zone.Value._entries.Count == 0))
if (((zone.Value._zones == null) || (zone.Value._zones.Count == 0)) && ((zone.Value._entries == null) || (zone.Value._entries.Count == 0)))
{
if (subZonesToRemove == null)
subZonesToRemove = new List<string>();
@@ -303,6 +317,9 @@ namespace DnsServerCore.Dns
{
foreach (string subZone in subZonesToRemove)
currentZone._zones.TryRemove(subZone, out Zone value);
if (currentZone._zones.Count == 0)
currentZone._zones = null;
}
}
}
@@ -314,6 +331,9 @@ namespace DnsServerCore.Dns
if (_authoritativeZone && (type == DnsResourceRecordType.ANY))
{
if (_entries == null)
return Array.Empty<DnsResourceRecord>();
List<DnsResourceRecord> allRecords = new List<DnsResourceRecord>();
foreach (KeyValuePair<DnsResourceRecordType, DnsResourceRecord[]> entry in _entries)
@@ -322,14 +342,14 @@ namespace DnsServerCore.Dns
return FilterExpiredDisabledRecords(allRecords.ToArray(), serveStale);
}
if (!bypassCNAME && _entries.TryGetValue(DnsResourceRecordType.CNAME, out DnsResourceRecord[] existingCNAMERecords))
if (!bypassCNAME && (_entries != null) && _entries.TryGetValue(DnsResourceRecordType.CNAME, out DnsResourceRecord[] existingCNAMERecords))
{
DnsResourceRecord[] records = FilterExpiredDisabledRecords(existingCNAMERecords, serveStale);
if (records != null)
return records;
}
if (_entries.TryGetValue(type, out DnsResourceRecord[] existingRecords))
if ((_entries != null) && _entries.TryGetValue(type, out DnsResourceRecord[] existingRecords))
{
DnsResourceRecord[] records = FilterExpiredDisabledRecords(existingRecords, serveStale);
@@ -348,17 +368,20 @@ namespace DnsServerCore.Dns
if (type == DnsResourceRecordType.ANY)
{
foreach (KeyValuePair<DnsResourceRecordType, DnsResourceRecord[]> entry in _entries)
if (_entries != null)
{
if (entry.Key != DnsResourceRecordType.ANY)
allRecords.AddRange(entry.Value);
foreach (KeyValuePair<DnsResourceRecordType, DnsResourceRecord[]> entry in _entries)
{
if (entry.Key != DnsResourceRecordType.ANY)
allRecords.AddRange(entry.Value);
}
}
}
else if (type == DnsResourceRecordType.AXFR)
{
includeSubDomains = true;
if (!_entries.TryGetValue(DnsResourceRecordType.SOA, out DnsResourceRecord[] soaRecord))
if ((_entries == null) || !_entries.TryGetValue(DnsResourceRecordType.SOA, out DnsResourceRecord[] soaRecord))
throw new DnsServerException("No SOA record found for AXFR in current zone.");
allRecords.Add(soaRecord[0]);
@@ -369,12 +392,12 @@ namespace DnsServerCore.Dns
allRecords.AddRange(entry.Value);
}
}
else if (_entries.TryGetValue(type, out DnsResourceRecord[] existingRecords))
else if ((_entries != null) && _entries.TryGetValue(type, out DnsResourceRecord[] existingRecords))
{
allRecords.AddRange(existingRecords);
}
if (includeSubDomains)
if (includeSubDomains && (_zones != null))
{
DnsResourceRecordType subType;
@@ -385,7 +408,7 @@ namespace DnsServerCore.Dns
foreach (KeyValuePair<string, Zone> zone in _zones)
{
if (!zone.Value._entries.ContainsKey(DnsResourceRecordType.SOA))
if ((zone.Value._entries != null) && !zone.Value._entries.ContainsKey(DnsResourceRecordType.SOA))
allRecords.AddRange(zone.Value.GetAllRecords(subType, true));
}
}
@@ -402,8 +425,11 @@ namespace DnsServerCore.Dns
if ((soa.Count > 0) && (soa[0].RDATA is DnsSOARecord))
zones.Add(this);
foreach (KeyValuePair<string, Zone> entry in _zones)
entry.Value.ListAuthoritativeZones(zones);
if (_zones != null)
{
foreach (KeyValuePair<string, Zone> entry in _zones)
entry.Value.ListAuthoritativeZones(zones);
}
}
private void SetRecords(DnsResourceRecordType type, DnsResourceRecord[] records)
@@ -411,16 +437,19 @@ namespace DnsServerCore.Dns
if (!_authoritativeZone && (records.Length > 0) && (records[0].RDATA is DnsCache.DnsFailureRecord))
{
//call trying to cache failure record
if (_entries.TryGetValue(type, out DnsResourceRecord[] existingRecords))
if ((_entries != null) && _entries.TryGetValue(type, out DnsResourceRecord[] existingRecords))
{
if ((existingRecords.Length > 0) && !(existingRecords[0].RDATA is DnsCache.DnsFailureRecord))
return; //skip to avoid overwriting a useful stale record with a failure record to allow serve-stale to work as intended
}
}
if (_authoritativeZone && (type == DnsResourceRecordType.CNAME) && _entries.ContainsKey(DnsResourceRecordType.SOA))
if (_authoritativeZone && (type == DnsResourceRecordType.CNAME) && (_entries != null) && _entries.ContainsKey(DnsResourceRecordType.SOA))
throw new DnsServerException("Cannot add CNAME record to zone root.");
if (_entries == null)
_entries = new ConcurrentDictionary<DnsResourceRecordType, DnsResourceRecord[]>(1, 5);
_entries.AddOrUpdate(type, records, delegate (DnsResourceRecordType key, DnsResourceRecord[] existingValues)
{
return records;
@@ -456,6 +485,9 @@ namespace DnsServerCore.Dns
throw new DnsServerException("Cannot add record: use SetRecords() for " + record.Type.ToString() + " record");
}
if (_entries == null)
_entries = new ConcurrentDictionary<DnsResourceRecordType, DnsResourceRecord[]>(1, 5);
_entries.AddOrUpdate(record.Type, new DnsResourceRecord[] { record }, delegate (DnsResourceRecordType key, DnsResourceRecord[] existingRecords)
{
foreach (DnsResourceRecord existingRecord in existingRecords)
@@ -475,7 +507,7 @@ namespace DnsServerCore.Dns
private void DeleteRecord(DnsResourceRecord record)
{
if (_entries.TryGetValue(record.Type, out DnsResourceRecord[] existingRecords))
if ((_entries != null) && _entries.TryGetValue(record.Type, out DnsResourceRecord[] existingRecords))
{
bool recordFound = false;
@@ -518,6 +550,9 @@ namespace DnsServerCore.Dns
{
_entries.TryRemove(type, out _);
if (_entries.Count == 0)
_entries = null;
DeleteEmptyParentZones(this);
}
@@ -584,6 +619,9 @@ namespace DnsServerCore.Dns
{
string nextZoneLabel = path[i];
if (currentZone._zones == null)
return currentZone;
if (currentZone._zones.TryGetValue(nextZoneLabel, out Zone nextZone))
currentZone = nextZone;
else if (currentZone._zones.TryGetValue("*", out Zone nextWildcardZone))
@@ -643,7 +681,7 @@ namespace DnsServerCore.Dns
while (currentZone != null)
{
if (currentZone._entries.ContainsKey(DnsResourceRecordType.SOA))
if ((_entries != null) && currentZone._entries.ContainsKey(DnsResourceRecordType.SOA))
{
nsRecords = currentZone.QueryRecords(DnsResourceRecordType.NS, true, false);
if ((nsRecords != null) && (nsRecords.Length > 0))
@@ -1056,7 +1094,10 @@ namespace DnsServerCore.Dns
{
Zone currentZone = GetZone(this, domain, false);
if (currentZone == null)
return new string[] { }; //no zone for given domain
return Array.Empty<string>(); //no zone for given domain
if (currentZone._zones == null)
return Array.Empty<string>(); //no sub zone for current zone
string[] subZoneNames = new string[currentZone._zones.Keys.Count];
currentZone._zones.Keys.CopyTo(subZoneNames, 0);
@@ -1139,8 +1180,8 @@ namespace DnsServerCore.Dns
public void Flush()
{
_zones.Clear();
_entries.Clear();
_zones = null;
_entries = null;
if (!_authoritativeZone)
LoadRootHintsInCache();