/// <summary>
/// Creates a new instance of this class
/// </summary>
public DNSResourceRecord()
{
dnsEnc = new DNSNameEncoder();
strName = "";
dnsType = DNSResourceType.All;
dnsClass = DNSResourceClass.Any;
}
/// <summary>
/// Creates a new instance of this class by parsing the given data
/// <seealso cref="DNSQuestion"/>
/// <example><code>
/// // For parsing DNS frames, set the index variable to the index where parsing should begin.
/// // This is in case of DNS frames 12 + the length of all records before this record
/// int iIndex = 12;
///
/// // Parse all records
/// while (lRecords.Count < iCount)
/// {
/// // Create a new DNS records from the data and pass the index as pointer to the constructor.
/// // The index will be increased during parsing so that it will point to the beginning of the next record.
/// DNSResourceRecord qLast = new DNSResourceRecord(bData, ref iIndex);
/// lRecords.Add(qLast);
/// }
/// </code></example>
/// </summary>
/// <param name="bData">The data to parse</param>
/// <param name="iParserIndex">The index where parsing starts. This index will be incremented automatically during parsing</param>
public DNSResourceRecord(byte[] bData, ref int iParserIndex)
{
dnsEnc = new DNSNameEncoder();
int iStringLen = 0;
strName = DNSNameEncoder.DecodeDNSName(bData, iParserIndex, ref iStringLen).Substring(1);
iParserIndex += iStringLen;
dnsType = (DNSResourceType)(((bData[iParserIndex]) << 8) + bData[iParserIndex + 1]);
dnsClass = (DNSResourceClass)(((bData[iParserIndex + 2]) << 8) + bData[iParserIndex + 3]);
iTTL = ((int)bData[iParserIndex + 4] << 24) + ((int)bData[iParserIndex + 5] << 16) + ((int)bData[iParserIndex + 6] << 8) + bData[iParserIndex + 7];
int iRDLen = ((int)bData[iParserIndex + 8] << 8) + bData[iParserIndex + 9];
iParserIndex += 10;
if (dnsType != DNSResourceType.CNAME)
{
bResourceData = new byte[iRDLen];
for (int iC1 = 0; iC1 < iRDLen; iC1++)
{
bResourceData[iC1] = bData[iParserIndex + iC1];
}
}
else
{
int iDummy = 0;
bResourceData = ASCIIEncoding.ASCII.GetBytes(DNSNameEncoder.DecodeDNSName(bData, iParserIndex, ref iDummy).Substring(1));
}
iParserIndex += iRDLen;
}
/// <summary>
/// Creates a new instance of this class
/// </summary>
public DNSQuestion()
{
dnsEnc = new DNSNameEncoder();
strQuestion = "";
qType = DNSResourceType.All;
qClass = DNSResourceClass.Any;
}
/// <summary>
/// Creates a new instance of this class by parsing the given data
/// <example><code>
/// // For parsing DNS frames, set the index variable to 12, because the question section starts there
/// int iIndex = 12;
///
/// // Parse all questions
/// while (lQuestions.Count < iQCount)
/// {
/// // Create a new DNS question from the data and pass the index as pointer to the constructor.
/// // The index will be increased during parsing so that it will point to the beginning of the next record.
/// DNSQuestion qLast = new DNSQuestion(bData, ref iIndex);
/// lQuestions.Add(qLast);
/// }
/// </code></example>
/// </summary>
/// <param name="bData">The data to parse</param>
/// <param name="iParserIndex">The index where parsing begins. This index must be passed as pointer for it will be increased during parsing.</param>
public DNSQuestion(byte[] bData, ref int iParserIndex)
{
dnsEnc = new DNSNameEncoder();
int iStringLen = 0;
strQuestion = DNSNameEncoder.DecodeDNSName(bData, iParserIndex, ref iStringLen).Substring(1);
iParserIndex += iStringLen;
qType = (DNSResourceType)(((bData[iParserIndex]) << 8) + bData[iParserIndex + 1]);
qClass = (DNSResourceClass)(((bData[iParserIndex + 2]) << 8) + bData[iParserIndex + 3]);
iParserIndex += 4;
}
/// <summary>
/// Returns the compressed bytes of this DNS question
/// <example><code>
/// // For constucting DNS frames, set the index variable to 12, because the question section starts there
/// int iIndex = 12;
/// // Create a new, empty dictionary
/// Dictionary<string, int> dictCompression = new Dictionary<string, int>();
///
/// // For all questions...
/// foreach (DNSQuestion q in lQuestions)
/// {
/// // Get the compressed bytes by passing the index at which this record will be inserted in the DNS frame and the dictionary to the corresponding method.
/// bData = q.GetCompressedBytes(dictCompression, iIndex);
///
/// // Increase the index value
/// iIndex += bData.Length;
///
/// // ... Do something with the data ...
/// }
///
/// // For a maximum compression factor re-use the same dictionary in the answer, authorotive and additional section of this frame.
/// </code></example>
/// </summary>
/// <param name="dictCompression">A dictionary containing strings and their corresponding indexes from a DNS frame. If this is the first call to this function for a specific DNS frame, an empty instance of
/// Dictionar<string, int> should be passed, which can be reused in further calls of this method</param>
/// <param name="iStartIndex">The index at which this record will be inseted</param>
/// <returns>This DNS question compressed as byte array</returns>
public byte[] GetCompressedBytes(Dictionary <string, int> dictCompression, int iStartIndex)
{
MemoryStream msStream = new MemoryStream();
byte[] bName = DNSNameEncoder.CompressDNSName(strQuestion, dictCompression, iStartIndex);
msStream.Write(bName, 0, bName.Length);
byte[] bData = new byte[4];
bData[0] = (byte)(((int)qType >> 8) & 0xFF);
bData[1] = (byte)(((int)qType) & 0xFF);
bData[2] = (byte)(((int)qClass >> 8) & 0xFF);
bData[3] = (byte)(((int)qClass) & 0xFF);
msStream.Write(bData, 0, bData.Length);
return(msStream.ToArray());
}
/// <summary>
/// Returns the compressed bytes of this DNS record
/// <example><code>
/// // For parsing DNS frames, set the index variable to the index where parsing should begin.
/// // This is in case of DNS frames 12 + the length of all records before this record
/// int iIndex = 12;
/// // If available, you should use the Dictionary created when compression the DNS questions. Else create a new, empty dictionary
/// Dictionary<string, int> dictCompression = new Dictionary<string, int>();
///
/// // For all recirds...
/// foreach (DNSResourceRecord r in lRecords)
/// {
/// // Get the compressed bytes by passing the index at which this record will be inserted in the DNS frame and the dictionary to the corresponding method.
/// bData = r.GetCompressedBytes(dictCompression, iIndex);
///
/// // Increase the index value
/// iIndex += bData.Length;
///
/// // ... Do something with the data ...
/// }
///
/// // For a maximum compression factor re-use the same dictionary in the other resource sections of the frame.
/// </code></example>
/// </summary>
/// <param name="dictCompression">A dictionary containing strings and their corresponding indexes from a DNS frame. If this is the first call to this function for a specific DNS frame, an empty instance of
/// Dictionar<string, int> should be passed, which can be reused in further calls of this method</param>
/// <param name="iStartIndex">The index at which this record will be inseted</param>
/// <returns>This DNS question compressed as byte array</returns>
public byte[] GetCompressedBytes(Dictionary <string, int> dictCompression, int iStartIndex)
{
MemoryStream msStream = new MemoryStream();
byte[] bName = DNSNameEncoder.CompressDNSName(strName, dictCompression, iStartIndex);
msStream.Write(bName, 0, bName.Length);
byte[] bData = new byte[10];
bData[0] = (byte)(((int)dnsType >> 8) & 0xFF);
bData[1] = (byte)(((int)dnsType) & 0xFF);
bData[2] = (byte)(((int)dnsClass >> 8) & 0xFF);
bData[3] = (byte)(((int)dnsClass) & 0xFF);
bData[4] = (byte)((iTTL >> 24) & 0xFF);
bData[5] = (byte)((iTTL >> 16) & 0xFF);
bData[6] = (byte)((iTTL >> 8) & 0xFF);
bData[7] = (byte)((iTTL) & 0xFF);
bData[8] = (byte)((bResourceData.Length >> 8) & 0xFF);
bData[9] = (byte)((bResourceData.Length) & 0xFF);
msStream.Write(bData, 0, bData.Length);
msStream.Write(bResourceData, 0, bResourceData.Length);
return(msStream.ToArray());
}
