![]() ![]() All someone has to do is pass in a ReadOnlySpan of ANY length, including 0 length. This is interesting code and I'm happy it works for you in your specific usage, but on a general level I find it lacking.įor starters, you have ZERO checks to validate the input bytes form a valid IPv4 header. In the above, the choice of doing the checksum calculations would depend on how you would want to manage the pressure on either side of the pipe. ReadResult result = await reader.ReadAsync(cancellationToken).ConfigureAwait(true) ReadFromPipeAsync() snippet while(!cancellationToken.IsCancellationRequested) try/finally, mark pipe complete via CompleteAsync(), etc. - use IsValidChecksum() if we are receiving - use GetInternetChecksum() if we are sending We can perform either of the checksum methods here _ = await socket.ReceiveAsync(buffer, socketFlags, cancellationToken) Memory buffer = writer.GetMemory(minimumBufferSize) WriteToPipeAsync() snippet while(!cancellationToken.IsCancellationRequested) Task reading = ReadFromPipeAsync(pipe.Reader, cancellationToken) Īwait Task.WhenAll(reading, writing).ConfigureAwait(true) Task writing = WriteToPipeAsync(pipe.Writer, _socket, cancellationToken) ResumeWriterThreshold: 1400) // or MTU - TCP/IP Headers Example UsageĬapturePacketsAsync() snippet PipeOptions options = new( when calculating the checksum, and includeĮDIT: I added some additional context surrounding the Extension Methods section (above) and I also added an example use case (below). Note: We should ignore the Header Checksum value bytes // Version and Internal Header Length / An implementation of the IPv4 header checksum calculation,įor a detailed explanation of the loop above: i = 0 e.g. => CalculateChecksum(bytes, ignoreHeaderChecksum: false) = 0 Public static bool IsValidChecksum(this ReadOnlySpan bytes) => CalculateChecksum(bytes, ignoreHeaderChecksum: true) public static ushort GetInternetChecksum(this ReadOnlySpan bytes) They differ only by ignoring the 10th byte (Header Checksum). They produce the API to expose the private method (below). Note: These are two extension methods to illustrate the only two use cases that a calculation of the checksum would be need in the context of reading bytes contained within a IPv4 packet. Appreciate any feedback! Extension Methods I made use of the "newer" ReadOnlySpan classes to optimize things a bit. So, I decided to made one as defined in RFC 791. I could not find an implementation of the IPv4 header checksum calculation. ![]()
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