byte[] PrepareDnsQuery()
{
// prepare the head
DnsDiagramHead diagramHead = new DnsDiagramHead();
diagramHead.id = DnsDiagramID;
diagramHead.flag = 0;
diagramHead.flag |= DnsHeadFlag.QRquery | DnsHeadFlag.RD | DnsHeadFlag.TC;
diagramHead.queryNum = 1;
// prepare the body
DnsQueryBody queryBody;
queryBody.queryName = new byte[targetHostName.Length + 1];
for (int i = 0, j = -1; i < targetHostName.Length; i++)
{
if (targetHostName[i] == '.')
{
// j contains the the previous index value of '.' in queryName
queryBody.queryName[j + 1] = (byte)(i - j - 1);
j = i;
}
else
{
queryBody.queryName[i + 1] = (byte)targetHostName[i];
}
}
queryBody.queryName[targetHostName.Length] = 0;
queryBody.queryType = 1; // 'A' address
queryBody.queryClass = 1; // IP address
int bufferSize = diagramHead.DiagramSize + queryBody.DiagramSize;
byte[] buffer = new byte[bufferSize];
int index = 0;
diagramHead.ToByteArray().CopyTo(buffer, index);
index += diagramHead.DiagramSize;
queryBody.ToByteArray().CopyTo(buffer, index);
index += queryBody.DiagramSize;
return(buffer);
}
