public StubZone(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 stub zone is considered expired till it refreshes
_refreshTimer = new Timer(RefreshTimerCallback, null, Timeout.Infinite, Timeout.Infinite);
}
private IReadOnlyList <NameServerAddress> GetNameServerAddresses(DnsServer dnsServer, DnsResourceRecord record)
{
string nsDomain;
switch (record.Type)
{
case DnsResourceRecordType.NS:
nsDomain = (record.RDATA as DnsNSRecord).NameServer;
break;
case DnsResourceRecordType.SOA:
nsDomain = (record.RDATA as DnsSOARecord).PrimaryNameServer;
break;
default:
throw new InvalidOperationException();
}
List <NameServerAddress> nameServers = new List <NameServerAddress>(2);
IReadOnlyList <DnsResourceRecord> glueRecords = record.GetGlueRecords();
if (glueRecords.Count > 0)
{
foreach (DnsResourceRecord glueRecord in glueRecords)
{
switch (glueRecord.Type)
{
case DnsResourceRecordType.A:
nameServers.Add(new NameServerAddress(nsDomain, (glueRecord.RDATA as DnsARecord).Address));
break;
case DnsResourceRecordType.AAAA:
if (dnsServer.PreferIPv6)
{
nameServers.Add(new NameServerAddress(nsDomain, (glueRecord.RDATA as DnsAAAARecord).Address));
}
break;
}
}
}
else
{
//resolve addresses
try
{
DnsDatagram response = dnsServer.DirectQuery(new DnsQuestionRecord(nsDomain, DnsResourceRecordType.A, DnsClass.IN));
if ((response != null) && (response.Answer.Count > 0))
{
IReadOnlyList <IPAddress> addresses = DnsClient.ParseResponseA(response);
foreach (IPAddress address in addresses)
{
nameServers.Add(new NameServerAddress(nsDomain, address));
}
}
}
catch
{ }
if (dnsServer.PreferIPv6)
{
try
{
DnsDatagram response = dnsServer.DirectQuery(new DnsQuestionRecord(nsDomain, DnsResourceRecordType.AAAA, DnsClass.IN));
if ((response != null) && (response.Answer.Count > 0))
{
IReadOnlyList <IPAddress> addresses = DnsClient.ParseResponseAAAA(response);
foreach (IPAddress address in addresses)
{
nameServers.Add(new NameServerAddress(nsDomain, address));
}
}
}
catch
{ }
}
}
return(nameServers);
}
