/// <summary>
/// Queries a the upstream DNS server(s) for specified records.
/// </summary>
/// <typeparam name="T"> Type of records, that should be returned </typeparam>
/// <param name="name"> Domain, that should be queried </param>
/// <param name="recordType"> Type the should be queried </param>
/// <param name="recordClass"> Class the should be queried </param>
/// <returns> A list of matching <see cref="DnsRecordBase">records</see> </returns>
public List <T> Resolve <T>(DomainName name, RecordType recordType = RecordType.A, RecordClass recordClass = RecordClass.INet)
where T : DnsRecordBase
{
if (name == null)
{
throw new ArgumentNullException(nameof(name), "Name must be provided");
}
List <T> records;
if (_cache.TryGetRecords(name, recordType, recordClass, out records))
{
return(records);
}
DnsMessage msg = _dnsClient.Resolve(name, recordType, recordClass);
if ((msg == null) || ((msg.ReturnCode != ReturnCode.NoError) && (msg.ReturnCode != ReturnCode.NxDomain)))
{
throw new Exception("DNS request failed");
}
CNameRecord cName = msg.AnswerRecords.Where(x => (x.RecordType == RecordType.CName) && (x.RecordClass == recordClass) && x.Name.Equals(name)).OfType <CNameRecord>().FirstOrDefault();
if (cName != null)
{
records = msg.AnswerRecords.Where(x => x.Name.Equals(cName.CanonicalName)).OfType <T>().ToList();
if (records.Count > 0)
{
_cache.Add(name, recordType, recordClass, records, DnsSecValidationResult.Indeterminate, records.Min(x => x.TimeToLive));
return(records);
}
records = Resolve <T>(cName.CanonicalName, recordType, recordClass);
if (records.Count > 0)
{
_cache.Add(name, recordType, recordClass, records, DnsSecValidationResult.Indeterminate, records.Min(x => x.TimeToLive));
}
return(records);
}
records = msg.AnswerRecords.Where(x => x.Name.Equals(name)).OfType <T>().ToList();
if (records.Count > 0)
{
_cache.Add(name, recordType, recordClass, records, DnsSecValidationResult.Indeterminate, records.Min(x => x.TimeToLive));
}
return(records);
}
} // End Class DbDnsRecord
static async Task <bool> ResolveMessage(DnsMessage query, QueryReceivedEventArgs e, DnsMessage response)
{
DbDnsRecord rec = null;
using (System.Data.Common.DbCommand cmd = s_sql.CreateCommand(@"
-- DECLARE @in_recordType int
-- DECLARE @in_recordName varchar(4000)
-- SET @in_recordType = 1 -- A
-- SET @in_recordName = 'vortex.data.microsoft.com'
SELECT
REC_Id
--,T_Records.REC_DOM_Id
,T_Records.REC_RT_Id
,T_Records.REC_Name
,T_Records.REC_Content
,T_Records.REC_ResponsibleName
,COALESCE(T_Records.REC_TTL, 100) AS REC_TTL
,T_Records.REC_Prio
,T_Records.REC_Weight
,T_Records.REC_Port
,T_Records.REC_SerialNumber
,T_Records.REC_RefreshInterval
,T_Records.REC_RetryInterval
,T_Records.REC_ExpireInterval
,T_Records.REC_NegativeCachingTTL
,T_Records.REC_AfsSubType
,T_Records.REC_ChangeDate
FROM T_Records
WHERE REC_RT_Id = @in_recordType
AND T_Records.REC_Name = @in_recordName
;
"))
{
try
{
string name = query.Questions[0].Name.ToString();
s_sql.AddParameter(cmd, "in_recordType", (int)query.Questions[0].RecordType);
s_sql.AddParameter(cmd, "in_recordName", name);
// TODO: Can return multiple records...
rec = s_sql.GetClass <DbDnsRecord>(cmd);
}
catch (System.Exception ex)
{
System.Console.WriteLine(ex.Message);
System.Console.WriteLine(ex.StackTrace);
}
} // End Using cmd
if (rec != null)
{
int ttl = 3600;
DnsRecordBase record = null;
// https://blog.dnsimple.com/2015/04/common-dns-records/
// https://en.wikipedia.org/wiki/List_of_DNS_record_types
switch ((RecordType)rec.REC_RT_Id)
{
case RecordType.Soa:
// SoaRecord(DomainName name, int timeToLive, DomainName masterName
// , DomainName responsibleName, uint serialNumber, int refreshInterval
// , int retryInterval, int expireInterval, int negativeCachingTTL)
record = new ARSoft.Tools.Net.Dns.SoaRecord(
DomainName.Parse(rec.REC_Name)
, rec.REC_TTL.Value
, DomainName.Parse(rec.REC_Content)
, DomainName.Parse(rec.REC_ResponsibleName)
, rec.REC_SerialNumber.Value
, rec.REC_RefreshInterval.Value
, rec.REC_RetryInterval.Value
, rec.REC_ExpireInterval.Value
, rec.REC_NegativeCachingTTL.Value
);
break;
case RecordType.Ns:
record = new ARSoft.Tools.Net.Dns.NsRecord(DomainName.Parse(rec.REC_Name), ttl, DomainName.Parse(rec.REC_Content));
break;
case RecordType.Srv:
// SrvRecord(DomainName name, int timeToLive, ushort priority, ushort weight, ushort port, DomainName target)
record = new ARSoft.Tools.Net.Dns.SrvRecord(DomainName.Parse(rec.REC_Name), rec.REC_TTL.Value, (ushort)rec.REC_Prio.Value, (ushort)rec.REC_Weight.Value, (ushort)rec.REC_Port.Value, DomainName.Parse(rec.REC_Content));
break;
// https://www.openafs.org/
// https://en.wikipedia.org/wiki/OpenAFS
// http://www.rjsystems.nl/en/2100-dns-discovery-openafs.php
// OpenAFS is an open source implementation of the Andrew distributed file system(AFS).
case RecordType.Afsdb:
// http://www.rjsystems.nl/en/2100-dns-discovery-openafs.php
record = new ARSoft.Tools.Net.Dns.AfsdbRecord(DomainName.Parse(rec.REC_Name), rec.REC_TTL.Value, (AfsdbRecord.AfsSubType)(uint) rec.REC_AfsSubType.Value, DomainName.Parse(rec.REC_Content));
break;
// A DNS-based Authentication of Named Entities (DANE) method
// for publishing and locating OpenPGP public keys in DNS
// for a specific email address using an OPENPGPKEY DNS resource record.
case RecordType.OpenPGPKey:
byte[] publicKey = null;
// hexdump(sha256(truncate(utf8(ocalpart), 28)
// https://www.huque.com/bin/openpgpkey
// The OPENPGPKEY DNS record is specied in RFC 7929.
// The localpart of the uid is encoded as a DNS label
// containing the hexdump of the SHA-256 hash
// of the utf-8 encoded localpart, truncated to 28 octets.
// Normally the "Standard" output format should be used.
// The "Generic Encoding" output format is provided to help work
// with older DNS software that does not yet understand the OPENPGPKEY record type.
record = new ARSoft.Tools.Net.Dns.OpenPGPKeyRecord(DomainName.Parse(rec.REC_Name), ttl, publicKey);
break;
// Canonical name records, or CNAME records, are often called alias records because they map an alias to the canonical name. When a name server finds a CNAME record, it replaces the name with the canonical name and looks up the new name.
case RecordType.CName:
record = new ARSoft.Tools.Net.Dns.CNameRecord(DomainName.Parse(rec.REC_Name), rec.REC_TTL.Value, DomainName.Parse(rec.REC_Content));
break;
case RecordType.Ptr:
record = new ARSoft.Tools.Net.Dns.PtrRecord(DomainName.Parse(rec.REC_Name), rec.REC_TTL.Value, DomainName.Parse(rec.REC_Content));
break;
case RecordType.A:
record = new ARSoft.Tools.Net.Dns.ARecord(DomainName.Parse(rec.REC_Name), rec.REC_TTL.Value, System.Net.IPAddress.Parse(rec.REC_Content));
break;
case RecordType.Aaaa:
record = new ARSoft.Tools.Net.Dns.AaaaRecord(DomainName.Parse(rec.REC_Name), rec.REC_TTL.Value, System.Net.IPAddress.Parse(rec.REC_Content));
break;
case RecordType.Mx:
record = new ARSoft.Tools.Net.Dns.MxRecord(DomainName.Parse(rec.REC_Name), rec.REC_TTL.Value, 0, DomainName.Parse(rec.REC_Content));
break;
case RecordType.Txt:
record = new ARSoft.Tools.Net.Dns.TxtRecord(DomainName.Parse(rec.REC_Name), rec.REC_TTL.Value, rec.REC_Content);
break;
case RecordType.SshFp:
// https://unix.stackexchange.com/questions/121880/how-do-i-generate-sshfp-records
// SshFpRecord(DomainName name, int timeToLive, SshFpAlgorithm algorithm
// , SshFpFingerPrintType fingerPrintType, byte[] fingerPrint)
ARSoft.Tools.Net.Dns.SshFpRecord.SshFpAlgorithm sfa = ARSoft.Tools.Net.Dns.SshFpRecord
.SshFpAlgorithm.Rsa;
ARSoft.Tools.Net.Dns.SshFpRecord.SshFpFingerPrintType sfp = ARSoft.Tools.Net.Dns.SshFpRecord
.SshFpFingerPrintType.Sha256;
byte[] fp = null;
record = new ARSoft.Tools.Net.Dns.SshFpRecord(DomainName.Parse(rec.REC_Name), rec.REC_TTL.Value, sfa, sfp, fp);
break;
default:
break;
} // End Switch
if (record != null)
{
response.AnswerRecords.Add(record);
}
response.ReturnCode = ReturnCode.NoError;
e.Response = response;
return(await Task <bool> .FromResult(true));
} // End if (rec != null)
return(await Task <bool> .FromResult(false));
} // End Function ResolveMessage
/// <summary>
/// Resolves specified records as an asynchronous operation.
/// </summary>
/// <typeparam name="T"> Type of records, that should be returned </typeparam>
/// <param name="name"> Domain, that should be queried </param>
/// <param name="recordType"> Type the should be queried </param>
/// <param name="recordClass"> Class the should be queried </param>
/// <param name="token"> The token to monitor cancellation requests </param>
/// <returns> A list of matching <see cref="DnsRecordBase">records</see> </returns>
public async Task <DnsSecResult <T> > ResolveSecureAsync <T>(DomainName name, RecordType recordType = RecordType.A, RecordClass recordClass = RecordClass.INet, CancellationToken token = default(CancellationToken))
where T : DnsRecordBase
{
if (name == null)
{
throw new ArgumentNullException(nameof(name), "Name must be provided");
}
DnsCacheRecordList <T> cacheResult;
if (_cache.TryGetRecords(name, recordType, recordClass, out cacheResult))
{
return(new DnsSecResult <T>(cacheResult, cacheResult.ValidationResult));
}
DnsMessage msg = await _dnsClient.ResolveAsync(name, recordType, recordClass, new DnsQueryOptions()
{
IsEDnsEnabled = true,
IsDnsSecOk = true,
IsCheckingDisabled = true,
IsRecursionDesired = true
}, token).ConfigureAwait(false);
if ((msg == null) || ((msg.ReturnCode != ReturnCode.NoError) && (msg.ReturnCode != ReturnCode.NxDomain)))
{
throw new Exception("DNS request failed");
}
DnsSecValidationResult validationResult;
CNameRecord cName = msg.AnswerRecords.Where(x => (x.RecordType == RecordType.CName) && (x.RecordClass == recordClass) && x.Name.Equals(name)).OfType <CNameRecord>().FirstOrDefault();
if (cName != null)
{
DnsSecValidationResult cNameValidationResult = await _validator.ValidateAsync(name, RecordType.CName, recordClass, msg, new List <CNameRecord>() { cName }, null, token).ConfigureAwait(false);
if ((cNameValidationResult == DnsSecValidationResult.Bogus) || (cNameValidationResult == DnsSecValidationResult.Indeterminate))
{
throw new DnsSecValidationException("CNAME record could not be validated");
}
var records = msg.AnswerRecords.Where(x => (x.RecordType == recordType) && (x.RecordClass == recordClass) && x.Name.Equals(cName.CanonicalName)).OfType <T>().ToList();
if (records.Count > 0)
{
DnsSecValidationResult recordsValidationResult = await _validator.ValidateAsync(cName.CanonicalName, recordType, recordClass, msg, records, null, token).ConfigureAwait(false);
if ((recordsValidationResult == DnsSecValidationResult.Bogus) || (recordsValidationResult == DnsSecValidationResult.Indeterminate))
{
throw new DnsSecValidationException("CNAME matching records could not be validated");
}
validationResult = cNameValidationResult == recordsValidationResult ? cNameValidationResult : DnsSecValidationResult.Unsigned;
_cache.Add(name, recordType, recordClass, records, validationResult, Math.Min(cName.TimeToLive, records.Min(x => x.TimeToLive)));
return(new DnsSecResult <T>(records, validationResult));
}
var cNameResults = await ResolveSecureAsync <T>(cName.CanonicalName, recordType, recordClass, token).ConfigureAwait(false);
validationResult = cNameValidationResult == cNameResults.ValidationResult ? cNameValidationResult : DnsSecValidationResult.Unsigned;
if (cNameResults.Records.Count > 0)
{
_cache.Add(name, recordType, recordClass, cNameResults.Records, validationResult, Math.Min(cName.TimeToLive, cNameResults.Records.Min(x => x.TimeToLive)));
}
return(new DnsSecResult <T>(cNameResults.Records, validationResult));
}
List <T> res = msg.AnswerRecords.Where(x => (x.RecordType == recordType) && (x.RecordClass == recordClass) && x.Name.Equals(name)).OfType <T>().ToList();
validationResult = await _validator.ValidateAsync(name, recordType, recordClass, msg, res, null, token).ConfigureAwait(false);
if ((validationResult == DnsSecValidationResult.Bogus) || (validationResult == DnsSecValidationResult.Indeterminate))
{
throw new DnsSecValidationException("Response records could not be validated");
}
if (res.Count > 0)
{
_cache.Add(name, recordType, recordClass, res, validationResult, res.Min(x => x.TimeToLive));
}
return(new DnsSecResult <T>(res, validationResult));
}
