public void DnsRecordFactory_ResolveARecord()
{
var header = new DnsResponseHeader(42, 256, 0, 1, 0, 0);
var responseMessage = new DnsResponseMessage(header, 0);
var info = new ResourceRecordInfo("query", ResourceRecordType.A, QueryClass.IN, 100, 4);
var ip = IPAddress.Parse("123.45.67.9");
var answer = new ARecord(info, ip);
responseMessage.AddAnswer(answer);
var response = responseMessage.AsQueryResponse(new NameServer(ip));
var answerBytes = ip.GetAddressBytes();
var raw = GetResponseBytes(response, answerBytes);
var handle = new DnsUdpMessageHandler(true);
var result = handle.GetResponseMessage(new System.ArraySegment <byte>(raw)).AsQueryResponse(new NameServer(ip));
Assert.Equal(result.Answers.Count, 1);
var resultAnswer = result.Answers.OfType <ARecord>().First();
Assert.Equal(resultAnswer.Address.ToString(), ip.ToString());
Assert.Equal(resultAnswer.DomainName.Value, "query.");
Assert.Equal(resultAnswer.RawDataLength, 4);
Assert.Equal(resultAnswer.RecordClass, QueryClass.IN);
Assert.Equal(resultAnswer.RecordType, ResourceRecordType.A);
Assert.True(resultAnswer.TimeToLive == 100);
Assert.True(result.Header.Id == 42);
Assert.True(result.Header.AnswerCount == 1);
}
private DnsResponseMessage GetDnsResponseMessage(int headerId = 0, string ipAddress = "10.0.0.10", string domainNameToResolveRoot = "www.microsoft.com.", int ttl = 10, int rawDataLen = 1024)
{
DnsResponseHeader header = new DnsResponseHeader(headerId, 0, 0, 0, 0, 0);
DnsResponseMessage message = new DnsResponseMessage(header, 0);
mockDnsString.Setup(m => m.Value).Returns(domainNameToResolveRoot);
message.Answers.Add(new ARecord(new BaseResourceRecordInfo(ResourceRecordType.A, QueryClass.IN, ttl, rawDataLen, mockDnsString.Object), IPAddress.Parse(ipAddress)));
return(message);
}
/// <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);
}
