/// <summary>
/// Sends query to server.
/// </summary>
/// <param name="qname">Query text.</param>
/// <param name="qtype">Query type.</param>
/// <param name="qclass">Query class.</param>
/// <returns></returns>
private DnsServerResponse QueryServer(string qname, QTYPE qtype, int qclass)
{
if (m_DnsServers == null || m_DnsServers.Length == 0)
{
throw new Exception("Dns server isn't specified !!!");
}
// See if query is in cache
if (m_UseDnsCache)
{
DnsServerResponse resopnse = DnsCache.GetFromCache(qname, (int)qtype);
if (resopnse != null)
{
return(resopnse);
}
}
int queryID = DnsEx.ID;
byte[] query = CreateQuery(queryID, qname, qtype, qclass);
int helper = 0;
for (int i = 0; i < (m_DnsServers.Length * 2); i++)
{
if (helper >= m_DnsServers.Length)
{
helper = 0;
}
try{
Socket udpClient = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
udpClient.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReceiveTimeout, 10000);
udpClient.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.SendTimeout, 10000);
udpClient.Connect(new IPEndPoint(IPAddress.Parse(m_DnsServers[helper]), 53));
//send query
udpClient.Send(query);
byte[] retVal = new byte[512];
int countRecieved = udpClient.Receive(retVal);
udpClient.Close();
// If reply is ok, return it
DnsServerResponse serverResponse = ParseAnswers(retVal, queryID);
// Cache query
if (m_UseDnsCache && serverResponse.ResponseCode == RCODE.NO_ERROR)
{
DnsCache.AddToCache(qname, (int)qtype, serverResponse);
}
return(serverResponse);
}
catch {
}
helper++;
}
// If we reach so far, we probably won't get connection to dsn server
return(new DnsServerResponse(false, RCODE.SERVER_FAILURE, null));
}
/// <summary>
/// Sends query to server.
/// </summary>
/// <param name="qname">Query text.</param>
/// <param name="qtype">Query type.</param>
/// <param name="qclass">Query class.</param>
/// <returns></returns>
private ArrayList QueryServer(string qname, QTYPE qtype, int qclass)
{
// See if query is in cache
if (m_UseDnsCache)
{
ArrayList entries = DnsCache.GetFromCache(qname, (int)qtype);
if (entries != null)
{
return(entries);
}
}
int queryID = DnsEx.ID;
byte[] query = CreateQuery(queryID, qname, qtype, qclass);
int helper = 0;
for (int i = 0; i < 10; i++)
{
if (helper > m_DnsServers.Length)
{
helper = 0;
}
try{
IPEndPoint ipRemoteEndPoint = new IPEndPoint(IPAddress.Parse(m_DnsServers[helper]), 53);
Socket udpClient = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
IPEndPoint ipLocalEndPoint = new IPEndPoint(IPAddress.Any, 0);
EndPoint localEndPoint = (EndPoint)ipLocalEndPoint;
udpClient.Bind(localEndPoint);
udpClient.Connect(ipRemoteEndPoint);
//send query
udpClient.Send(query);
// Wait until we have a reply
byte[] retVal = null;
if (udpClient.Poll(5 * 1000000, SelectMode.SelectRead))
{
retVal = new byte[512];
udpClient.Receive(retVal);
}
udpClient.Close();
// If reply is ok, return it
ArrayList answers = ParseAnswers(retVal, queryID);
if (answers != null)
{
// Cache query
if (m_UseDnsCache && answers.Count > 0)
{
DnsCache.AddToCache(qname, (int)qtype, answers);
}
return(answers);
}
}
catch {
}
helper++;
}
return(null);
}