/// <summary> Constructs the response object based upon the data received from the DNS server. </summary>
/// <param name="responseData">The data (byte[]) from the DNS server.</param>
/// <returns>Response message object.</returns>
public DnsResponseMessage ProcessResponse(ArraySegment <byte> responseData)
{
IDnsRecordFactory factory = new DnsRecordFactory(reader);
/*
* From index 0 till 11 bytes in the responseData array, we have the header items.
*/
ushort id = reader.ReadUInt16NetworkOrder(responseData);
ushort flags = reader.ReadUInt16NetworkOrder(responseData);
ushort questionCount = reader.ReadUInt16NetworkOrder(responseData);
ushort answerCount = reader.ReadUInt16NetworkOrder(responseData);
ushort nameServerCount = reader.ReadUInt16NetworkOrder(responseData);
ushort additionalCount = reader.ReadUInt16NetworkOrder(responseData);
/*
* We have got above data, now build the response header.
*/
DnsResponseHeader header = new DnsResponseHeader(id, flags, questionCount, answerCount, additionalCount, nameServerCount);
DnsResponseMessage response = new DnsResponseMessage(header, responseData.Count);
/*
* Next item in the response data is question that we sent to the DNS server which the server has copied onto the response message.
*/
for (int questionIndex = 0; questionIndex < questionCount; questionIndex++)
{
IDnsString questionString = reader.ReadQuestionQueryString(responseData);
DnsQuestion question = new DnsQuestion(questionString, (QueryType)reader.ReadUInt16NetworkOrder(responseData), (QueryClass)reader.ReadUInt16NetworkOrder(responseData));
response.AddQuestion(question);
}
for (int answerIndex = 0; answerIndex < answerCount; answerIndex++)
{
BaseResourceRecordInfo info = factory.ReadRecordInfo(responseData);
DnsResourceRecord record = factory.GetRecord(info, responseData);
response.AddAnswer(record);
}
for (int serverIndex = 0; serverIndex < nameServerCount; serverIndex++)
{
BaseResourceRecordInfo info = factory.ReadRecordInfo(responseData);
DnsResourceRecord record = factory.GetRecord(info, responseData);
response.AddAuthority(record);
}
for (int additionalIndex = 0; additionalIndex < additionalCount; additionalIndex++)
{
BaseResourceRecordInfo info = factory.ReadRecordInfo(responseData);
DnsResourceRecord record = factory.GetRecord(info, responseData);
response.AddAdditional(record);
}
return(response);
}
public void GetRecord_should_throw_InvalidOperationException_when_Record_reader_index_becomes_out_of_sync()
{
// Arrange.
const string query = "www.msn.com";
const string queryRoot = query + ".";
const ResourceRecordType recordType = ResourceRecordType.A;
const QueryClass queryClass = QueryClass.IN; // IN
const int timeToLive = 1000;
const int rawDataLen = 10;
IPAddress ipaddress = IPAddress.Parse("10.1.1.100");
IDnsString dnsString = new DnsString(query, queryRoot);
BaseResourceRecordInfo info = new BaseResourceRecordInfo(recordType, queryClass, timeToLive, rawDataLen, dnsString);
ArraySegment <byte> responseData = GetSampleData(ResponseDataSampleFile.QuestionAndAnswerQuery);
mockReader.Setup(r => r.Index).Returns(100);
mockReader.Setup(r => r.ReadIPAddress(responseData)).Returns(ipaddress);
IDnsRecordFactory factory = new DnsRecordFactory(mockReader.Object);
// Act.
Assert.Throws <InvalidOperationException>(() => factory.GetRecord(info, responseData), "Record reader index out of sync.");
}
public void GetRecord_should_return_EmptyRecord_type_when_unknown_recordType_is_found()
{
// Arrange.
const string query = "www.msn.com";
const string queryRoot = query + ".";
const ResourceRecordType recordType = ResourceRecordType.OPT; // possibly make it to default case in the switch statement.
const QueryClass queryClass = QueryClass.IN; // IN
const int timeToLive = 1000;
const int rawDataLen = 10;
IPAddress ipaddress = IPAddress.Parse("10.1.1.100");
IDnsString dnsString = new DnsString(query, queryRoot);
BaseResourceRecordInfo info = new BaseResourceRecordInfo(recordType, queryClass, timeToLive, rawDataLen, dnsString);
ArraySegment <byte> responseData = GetSampleData(ResponseDataSampleFile.QuestionAndAnswerQuery);
mockReader.SetupSequence(r => r.Index).Returns(100).Returns(100 + rawDataLen);
mockReader.Setup(r => r.ReadIPAddress(responseData)).Returns(ipaddress);
IDnsRecordFactory factory = new DnsRecordFactory(mockReader.Object);
// Act.
DnsResourceRecord result = factory.GetRecord(info, responseData);
// Assert.
Assert.IsInstanceOf(typeof(EmptyRecord), result);
EmptyRecord record = (EmptyRecord)result;
}
public void GetRecord_should_return_RecordTypeA()
{
// Arrange.
const string query = "www.msn.com";
const string queryRoot = query + ".";
const ResourceRecordType recordType = ResourceRecordType.A; // A - Host Address.
const QueryClass queryClass = QueryClass.IN; // IN
const int timeToLive = 1000;
const int rawDataLen = 10;
IPAddress ipaddress = IPAddress.Parse("10.1.1.100");
IDnsString dnsString = new DnsString(query, queryRoot);
BaseResourceRecordInfo info = new BaseResourceRecordInfo(recordType, queryClass, timeToLive, rawDataLen, dnsString);
ArraySegment <byte> responseData = GetSampleData(ResponseDataSampleFile.QuestionAndAnswerQuery);
mockReader.SetupSequence(r => r.Index).Returns(100).Returns(100 + rawDataLen);
mockReader.Setup(r => r.ReadIPAddress(responseData)).Returns(ipaddress);
IDnsRecordFactory factory = new DnsRecordFactory(mockReader.Object);
// Act.
DnsResourceRecord result = factory.GetRecord(info, responseData);
// Assert.
Assert.IsInstanceOf(typeof(ARecord), result);
ARecord record = (ARecord)result;
Assert.AreEqual(queryRoot, record.DomainName.ToString());
Assert.AreEqual(ipaddress.ToString(), record.Address.ToString());
Assert.AreEqual(recordType, record.RecordType);
Assert.AreEqual(queryClass, record.RecordClass);
Assert.AreEqual(timeToLive, record.TimeToLive);
Assert.AreEqual(rawDataLen, record.RawDataLength);
}