Request.FromStream for handling DNS over TCP?

[GF-Huang]

Is there any plans? Or will accept any PRs?

[kapetan]

It's something I've considered and looked into before, but the problem is all the parsing and serializing is done using byte arrays, so this might require many changes. I'm not sure I want such big refactoring.

[GF-Huang]

Maybe a simplest workaround, but not best performance. And consider using PipeReader instead of List<byte> to improve performance.

public Task<Request> FromStream(Stream stream) {
    var reader = new Reader(stream);
    Request request = null;
    List<byte> data = new();
    do {
        var d = reader.ReadMoreData();
        if (d.Length != 0)
            data.AddRange(d);

        try {
            request = Request.FromArray(data);
            break;

        } catch {
            if (d.Length == 0) // no more data but still parse fail
                // throw something exception say invalid data parse fail
        }
    } while (request == null);
}

references:

• https://docs.microsoft.com/en-us/dotnet/standard/io/pipelines

[kapetan]

I'm not sure I like this approach, it might give people the impression that it's streaming the request, but it's actually reading everything into memory. Also people can add this in their code.

[GF-Huang]

So the only way is to refactor 😢

[GF-Huang]

I found that the DNS over TCP will contains a Length field at the first two bytes in the stream. So I think Request.FromStream is not necessary.

reference: https://tools.ietf.org/html/rfc7766#page-11