DnsResourceRecord ParseDnsResourceRecord(byte[] buffer, int beginIndex, ref int parseCount)
{
DnsResourceRecord resourceRecord = new DnsResourceRecord();
int index = beginIndex;
byte nameFlag = buffer[index];
if ((nameFlag & 0xc0) == 0xc0) // check if the domain name is a 16-bit pointer;
{
resourceRecord.domainName = new Byte[sizeof(Int16)];
Array.Copy(buffer, index, resourceRecord.domainName, 0, sizeof(Int16));
index += sizeof(Int16);
}
else // reach here means it is a domain name string
{
// get the length of the query name
int nameLength = 0;
int sectionLen;
index = beginIndex;
while ((sectionLen = buffer[index]) != 0)
{
nameLength += sectionLen + 1;
index += sectionLen + 1;
}
nameLength += 1; // add the count of the last '0'
index++;
resourceRecord.domainName = new byte[nameLength];
Array.Copy(buffer, index, resourceRecord.domainName, 0, nameLength);
}
resourceRecord.resType = IPAddress.NetworkToHostOrder(BitConverter.ToInt16(buffer, index));
index += sizeof(Int16);
resourceRecord.resClass = IPAddress.NetworkToHostOrder(BitConverter.ToInt16(buffer, index));
index += sizeof(Int16);
resourceRecord.ttl = IPAddress.NetworkToHostOrder(BitConverter.ToInt32(buffer, index));
index += sizeof(Int32);
resourceRecord.resLength = IPAddress.NetworkToHostOrder(BitConverter.ToInt16(buffer, index));
index += sizeof(Int16);
resourceRecord.resContent = new Byte[resourceRecord.resLength];
Array.Copy(buffer, index, resourceRecord.resContent, 0, resourceRecord.resLength);
index += resourceRecord.resLength;
parseCount = index - beginIndex;
return(resourceRecord);
}
