static void FormatSection(IReadOnlyList <DnsResourceRecord>?secton, ref DnsFormatContext context)
{
if (secton is null)
{
return;
}
foreach (var record in secton)
{
context.WriteDomainName(record.Name ?? throw new InvalidOperationException("RR must have name"));
context.WriteUInt16((ushort)record.Type);
context.WriteUInt16((ushort)record.EndpointClass);
context.WriteInt32(record.AliveSeconds);
var lengthSpan = context.AvailableSpan;
context.BytesWritten += 2;
int dataLength = record.WriteData(ref context);
BinaryPrimitives.WriteUInt16BigEndian(lengthSpan, checked ((ushort)dataLength));
}
}
public static int FormatMessage(DnsMessage message, Span <byte> destination, bool enableNameCompression = false)
{
var context = new DnsFormatContext(destination, enableNameCompression);
ushort flags = 0;
if (message.IsResponse)
{
flags |= ResponseFlag;
}
flags |= (ushort)((ushort)message.Operation << OpCodeShift);
if (message.IsAuthoritativeAnswer)
{
flags |= AuthoritativeMask;
}
//if (message.IsTruncated)
// flags |= TruncationMask;
if (message.IsRecursionDesired)
{
flags |= RecursionDesiredMask;
}
if (message.IsRecursionAvailable)
{
flags |= RecursionAvailableMask;
}
flags |= (ushort)message.ResponseCode;
context.WriteUInt16(message.QueryId);
context.WriteUInt16(flags);
context.WriteUInt16(checked ((ushort)message.Queries.Count));
context.WriteUInt16(checked ((ushort)(message.Answers?.Count ?? 0)));
context.WriteUInt16(checked ((ushort)(message.NameServerAuthorities?.Count ?? 0)));
context.WriteUInt16(checked ((ushort)(message.AdditionalRecords?.Count ?? 0)));