private byte[] GetQuery(byte[] query, int queryID)
{
byte[] retVal = null;
try
{
int helper = 0;
int count = 0;
while (count < 10)
{
if (count > m_DnsServers.Length)
{
helper = 0;
}
byte[] reply = QueryServer(query, m_DnsServers[helper]);
Dns_Answers answers = new Dns_Answers();
// If reply is ok, return it
if (reply != null && answers.ParseAnswers(reply, queryID))
{
return(reply);
}
count++;
helper++;
}
}
catch {
}
return(retVal);
}
/// <summary>
/// Gets MX records.(MX records are sorted by preference, lower array element is prefered)
/// </summary>
/// <param name="domain"></param>
/// <param name="mxRecords"></param>
/// <returns></returns>
public DnsReplyCode GetMXRecords(string domain, out MX_Record[] mxRecords)
{
//--- Try to get MX records from cache
mxRecords = DnsCache.GetMXFromCache(domain);
if (mxRecords != null)
{
// Console.WriteLine("domain:" + domain + " from cahce.");
return(DnsReplyCode.Ok);
}
//------------------------------------//
Dns_Header header = new Dns_Header(DnsEx.ID, OPCODE.IQUERY);
Dns_Query query = new Dns_Query(domain, QTYPE.MX, 1);
byte[] bQuery = query.GetQuery(header);
byte[] reply = GetQuery(bQuery, header.ID);
if (reply != null)
{
Dns_Answers answers = new Dns_Answers();
if (answers.ParseAnswers(reply, header.ID))
{
mxRecords = answers.GetMxRecordsFromAnswers();
if (mxRecords != null)
{
// Add to cache
DnsCache.AddMXToCache(domain, mxRecords);
return(DnsReplyCode.Ok);
}
else
{
return(DnsReplyCode.NoEntries);
}
}
}
return(DnsReplyCode.TempError);
}
