/// <summary>
/// Apply a TSIG record to the request message.
/// </summary>
/// <param name="dnsQueryRequest">The <see cref="DnsQueryRequest"/> to add the security headers too.</param>
/// <returns>A <see cref="DnsQueryRequest"/> instance with additional security attributes assigned.</returns>
public DnsQueryRequest SecureMessage(DnsQueryRequest dnsQueryRequest)
{
DateTime signDateTime = DateTime.Now;
int timeHigh;
long timeLow;
byte[] messageBytes = dnsQueryRequest.GetMessageBytes();
Trace.WriteLine(String.Format("Message Header Bytes: {0}", DnsHelpers.DumpArrayToString(messageBytes)));
MemoryStream memoryStream = new MemoryStream();
memoryStream.Write(messageBytes, 0, messageBytes.Length);
// the shared key name
byte[] data = DnsHelpers.CanonicaliseDnsName(_name, false);
memoryStream.Write(data, 0, data.Length);
data = BitConverter.GetBytes((ushort) (IPAddress.HostToNetworkOrder((ushort) NsClass.ANY) >> 16));
memoryStream.Write(data, 0, data.Length);
// the TTL value
data = BitConverter.GetBytes((uint) (IPAddress.HostToNetworkOrder((uint) 0) >> 32));
memoryStream.Write(data, 0, data.Length);
// the algorithim name
data = DnsHelpers.CanonicaliseDnsName(_algorithimName, true);
memoryStream.Write(data, 0, data.Length);
DnsHelpers.ConvertToDnsTime(signDateTime.ToUniversalTime(), out timeHigh, out timeLow);
data = BitConverter.GetBytes((ushort)(IPAddress.HostToNetworkOrder((ushort)timeHigh) >> 16));
memoryStream.Write(data, 0, data.Length);
data = BitConverter.GetBytes((uint) (IPAddress.HostToNetworkOrder((uint)timeLow) >> 32));
memoryStream.Write(data, 0, data.Length);
data = BitConverter.GetBytes((ushort) (IPAddress.HostToNetworkOrder(_fudge) >> 16));
memoryStream.Write(data, 0, data.Length);
data = BitConverter.GetBytes((ushort) (IPAddress.HostToNetworkOrder((ushort) RCode.NoError) >> 16));
memoryStream.Write(data, 0, data.Length);
// no other data
data = BitConverter.GetBytes((ushort) (IPAddress.HostToNetworkOrder((ushort) 0) >> 16));
memoryStream.Write(data, 0, data.Length);
byte[] dataToHash = memoryStream.ToArray();
Trace.WriteLine(String.Format("Data to hash: {0}", DnsHelpers.DumpArrayToString(dataToHash)));
byte[] mac = _hmac.ComputeHash(dataToHash);
Trace.WriteLine(String.Format("hash: {0}", DnsHelpers.DumpArrayToString(mac)));
dnsQueryRequest.AdditionalRRecords.Add(new TSigRecord(_name, _algorithimName, RCode.NoError, _fudge, dnsQueryRequest.TransactionID, new byte[] { }, mac, signDateTime));
return dnsQueryRequest;
}
