internal DnsResponse(DnsReader br)
{
_header = new DnsHeader(br);
_numQuestions = br.ReadInt16();
_numAnswers = br.ReadInt16();
_numNameServers = br.ReadInt16();
_numAdditionalRecords = br.ReadInt16();
#if (MF)
_questions = new Question[_numQuestions];
_answers = new Answer[_numAnswers];
_authorities = new Authority[_numNameServers];
_additionalRecords = new Additional[_numAdditionalRecords];
#endif
#if (MF)
for (int i = 0; i < _numQuestions; i++)
{
_questions[i] = new Question(br);
}
for (int i = 0; i < _numAnswers; i++)
{
_answers[i] = new Answer(br);
}
for (int i = 0; i < _numNameServers; i++)
{
_authorities[i] = new Authority(br);
}
for (int i = 0; i < _numAdditionalRecords; i++)
{
_additionalRecords[i] = new Additional(br);
}
#else
for (int i = 0; i < _numQuestions; i++)
{
_questions.Add(new Question(br));
}
for (int i = 0; i < _numAnswers; i++)
{
_answers.Add(new Answer(br));
}
for (int i = 0; i < _numNameServers; i++)
{
_authorities.Add(new Authority(br));
}
for (int i = 0; i < _numAdditionalRecords; i++)
{
_additionalRecords.Add(new Additional(br));
}
#endif
}
internal SOARecord(DnsReader br)
{
_mname = br.ReadDomain();
_rname = br.ReadDomain();
_serial = br.ReadInt32();
_refresh = br.ReadInt32();
_retry = br.ReadInt32();
_expire = br.ReadInt32();
_minimumTtl = br.ReadInt32();
}
/// <summary>
/// Reads a domain name from the byte array. (RFC 1035 - 4.1.4.)
/// </summary>
public string ReadDomain()
{
StringBuilder domain = new StringBuilder();
int length = 0;
while ((length = ReadByte()) != 0)
{
// top 2 bits set denotes domain name compression and to reference elsewhere
if ((length & 0xc0) == 0xc0)
{
// work out the existing domain name, copy this pointer
DnsReader newPointer = Copy();
// and move it to where specified here
newPointer.Position = (length & 0x3f) << 8 | ReadByte();
// repeat call recursively
domain.Append(newPointer.ReadDomain());
return(domain.ToString());
}
// if not using compression, copy a char at a time to the domain name
while (length > 0)
{
domain.Append(ReadChar());
length--;
}
// if size of next label isn't null (end of domain name) add a period ready for next label
if (Peek() != 0)
{
domain.Append('.');
}
}
return(domain.ToString());
}
internal ResourceRecord(DnsReader br)
{
_domain = br.ReadDomain();
_qtype = (DnsType)br.ReadInt16();
_qclass = (DnsClass)br.ReadInt16();
_ttl = br.ReadInt32();
int recordLength = br.ReadInt16();
if (recordLength != 0)
{
switch (_qtype)
{
case DnsType.A: _record = new ARecord(br); break;
case DnsType.CNAME: _record = new CNAMERecord(br); break;
case DnsType.MX: _record = new MXRecord(br); break;
case DnsType.NS: _record = new NSRecord(br); break;
case DnsType.SOA: _record = new SOARecord(br); break;
case DnsType.TXT: _record = new TXTRecord(br); break;
case DnsType.PTR: _record = new PTRERecord(br); break;
// NetBIOS related records
case DnsType.NB: _record = new NBRecord(br); break;
default:
br += recordLength;
break;
}
}
}
internal ARecord(DnsReader br)
{
_ipAddress = new IPAddress(br.ReadBytes(4));
}
internal Authority(DnsReader br) : base(br)
{
}
internal Question(DnsReader br)
{
_domain = br.ReadDomain();
_qtype = (DnsType)br.ReadInt16();
_qclass = (DnsClass)br.ReadInt16();
}
internal CNAMERecord(DnsReader br)
{
_domain = br.ReadDomain();
}
internal NSRecord(DnsReader br)
{
_domainName = br.ReadDomain();
}
internal MXRecord(DnsReader br)
{
_preference = br.ReadInt16();
_domainName = br.ReadDomain();
}
public DnsResponse Resolve(DnsRequest request)
{
int attempts = 0;
if (request.Header.MessageID == 0)
{
request.Header.MessageID = _nextMessageID++;
}
while (attempts <= _maxRetryAttemps)
{
byte[] bytes = request.GetMessage();
if (bytes.Length > 512)
{
throw new ArgumentException("RFC 1035 2.3.4 states that the maximum size of a UDP datagram is 512 octets (bytes).");
}
Socket socket = new Socket(
#if (MF)
AddressFamily.InterNetwork
#else
_endPoint.AddressFamily
#endif
, SocketType.Dgram, ProtocolType.Udp);
socket.ReceiveTimeout = 300;
//socket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReceiveTimeout, 300);
socket.SendTo(bytes, bytes.Length, SocketFlags.None, _endPoint);
// Messages carried by UDP are restricted to 512 bytes (not counting the IP
// or UDP headers). Longer messages are truncated and the TC bit is set in
// the header. (RFC 1035 4.2.1)
byte[] responseMessage = new byte[512];
try
{
//int numBytes = socket.Receive(responseMessage);
EndPoint ep = (EndPoint)_endPoint;
int numBytes = socket.ReceiveFrom(responseMessage, ref ep);
if (numBytes == 0 || numBytes > 512)
{
throw new Exception("RFC 1035 2.3.4 states that the maximum size of a UDP datagram is 512 octets (bytes).");
}
DnsReader br = new DnsReader(responseMessage);
DnsResponse res = new DnsResponse(br);
if (request.Header.MessageID == res.Header.MessageID)
{
return(res);
}
_lastException = new Exception("Not the answer for the current query.");
attempts++;
}
catch (SocketException se)
{
_lastException = se;
attempts++;
}
finally
{
socket.Close();
socket = null;
}
}
throw new Exception("Could not resolve the query (" + attempts + " attempts).");
}
internal Additional(DnsReader br) : base(br)
{
}
internal TXTRecord(DnsReader br)
{
_txtData = br.ReadString();
}
internal DnsResponse Invoke(DnsRequest request, bool isQuery)
{
int attempts = 0;
if (request.Header.MessageID == 0)
{
request.Header.MessageID = _nextMessageID++;
}
while (attempts <= _maxRetryAttemps)
{
byte[] bytes = request.GetMessage();
if (bytes.Length > 512)
{
throw new ArgumentException("RFC 1035 2.3.4 states that the maximum size of a UDP datagram is 512 octets (bytes).");
}
Socket socket = null;
try
{
socket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
socket.ReceiveTimeout = 300;
//socket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReceiveTimeout, 300);
#if (DEBUG && MF)
Microsoft.SPOT.Debug.Print(MFToolkit.IO.ByteUtil.PrintBytes(bytes));
#endif
socket.SendTo(bytes, bytes.Length, SocketFlags.None, new IPEndPoint(IPAddress.Parse("192.168.178.255"), 137));
if (!isQuery)
{
return(null);
}
// Messages carried by UDP are restricted to 512 bytes (not counting the IP
// or UDP headers). Longer messages are truncated and the TC bit is set in
// the header. (RFC 1035 4.2.1)
byte[] responseMessage = new byte[512];
//int numBytes = socket.Receive(responseMessage);
EndPoint ep = (EndPoint) new IPEndPoint(new IPAddress(4294967295), 137);
int numBytes = socket.ReceiveFrom(responseMessage, ref ep);
if (numBytes == 0 || numBytes > 512)
{
throw new Exception("RFC 1035 2.3.4 states that the maximum size of a UDP datagram is 512 octets (bytes).");
}
DnsReader br = new DnsReader(responseMessage);
DnsResponse res = new DnsResponse(br);
if (request.Header.MessageID == res.Header.MessageID)
{
return(res);
}
_lastException = new Exception("Not the answer for the current query.");
attempts++;
}
catch (SocketException se)
{
_lastException = se;
attempts++;
}
finally
{
socket.Close();
socket = null;
}
}
throw new Exception("Could not resolve the query (" + attempts + " attempts).");
}
internal Answer(DnsReader br) : base(br)
{
}
internal NBRecord(DnsReader br)
{
_flags = br.ReadUInt16();
_ipAddress = new IPAddress(br.ReadBytes(4));
}