private Response SearchInCache(Question question)
{
if (!m_UseCache)
return null;
string strKey = question.QClass + "-" + question.QType + "-" + question.QName;
Response response = null;
if (!m_ResponseCache.TryGetValue(strKey, out response))
return null;
int TimeLived = (int)((DateTime.Now.Ticks - response.TimeStamp.Ticks) / TimeSpan.TicksPerSecond);
foreach (RR rr in response.RecordsRR)
{
rr.TimeLived = TimeLived;
// The TTL property calculates its actual time to live
if (rr.TTL == 0)
return null; // out of date
}
return response;
}
public void AddQuestion(Question question)
{
questions.Add(question);
}
/// <summary>
/// Do an QClass=IN Query on specified DNS servers
/// </summary>
/// <param name="name">Name to query</param>
/// <param name="qtype">Question type</param>
/// <returns>Response of the query</returns>
public Response Query(string name, QType qtype)
{
Question question = new Question(name, qtype, QClass.IN);
Response response = SearchInCache(question);
if (response != null)
return response;
Request request = new Request();
request.AddQuestion(question);
return GetResponse(request);
}