public static AddToCache ( string qname, int qtype, |
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qname | string | |
qtype | int | |
answers | ||
리턴 | void |
/// <summary> /// Is called when IPv6 socket has received data. /// </summary> /// <param name="ar">The result of the asynchronous operation.</param> private void IPv6ReceiveCompleted(IAsyncResult ar) { try{ if (m_IsDisposed) { return; } EndPoint remoteEP = new IPEndPoint(IPAddress.Any, 0); int count = m_pIPv6Socket.EndReceiveFrom(ar, ref remoteEP); DnsServerResponse serverResponse = ParseQuery((byte[])ar.AsyncState); DnsTransaction transaction = null; // Pass response to transaction. if (m_pTransactions.TryGetValue(serverResponse.ID, out transaction)) { transaction.ProcessResponse(serverResponse); } // No such transaction or transaction has timed out before answer received. //else{ //} // Cache query. if (m_UseDnsCache && serverResponse.ResponseCode == RCODE.NO_ERROR) { DnsCache.AddToCache(transaction.QName, transaction.QType, serverResponse); } } catch { // Skip receiving socket errors. } try{ StartWaitingIPv6Packet(); } catch { } }
/// <summary> /// Sends query to server. /// </summary> /// <param name="timeout">Query timeout in milli seconds.</param> /// <param name="qname">Query text.</param> /// <param name="qtype">Query type.</param> /// <param name="qclass">Query class.</param> /// <returns></returns> private DnsServerResponse QueryServer(int timeout, 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 = Dns_Client.ID; byte[] query = CreateQuery(queryID, qname, qtype, qclass); // Create sending UDP socket. Socket udpClient = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp); udpClient.SendTimeout = 500; // Send parallel query to all dns servers and get first answer. DateTime startTime = DateTime.Now; while (startTime.AddMilliseconds(timeout) > DateTime.Now) { foreach (IPAddress dnsServer in m_DnsServers) { try{ udpClient.SendTo(query, new IPEndPoint(dnsServer, 53)); } catch { } } // Wait 10 ms response to arrive, if no response, retransmit query. if (udpClient.Poll(10, SelectMode.SelectRead)) { try{ byte[] retVal = new byte[1024]; int countRecieved = udpClient.Receive(retVal); // If reply is ok, return it DnsServerResponse serverResponse = ParseQuery(retVal, queryID); // Cache query if (m_UseDnsCache && serverResponse.ResponseCode == RCODE.NO_ERROR) { DnsCache.AddToCache(qname, (int)qtype, serverResponse); } return(serverResponse); } catch { } } } udpClient.Close(); // If we reach so far, we probably won't get connection to dsn server return(new DnsServerResponse(false, RCODE.SERVER_FAILURE, new List <DNS_rr_base>(), new List <DNS_rr_base>(), new List <DNS_rr_base>())); }