public static byte[] BuildSettingsFrame(HttpConnectionSettings settings)
{
Span <byte> buffer = stackalloc byte[4 + VariableLengthIntegerHelper.MaximumEncodedLength];
int integerLength = VariableLengthIntegerHelper.WriteInteger(buffer.Slice(4), settings._maxResponseHeadersLength * 1024L);
int payloadLength = 1 + integerLength; // includes the setting ID and the integer value.
Debug.Assert(payloadLength <= VariableLengthIntegerHelper.OneByteLimit);
buffer[0] = (byte)Http3StreamType.Control;
buffer[1] = (byte)Http3FrameType.Settings;
buffer[2] = (byte)payloadLength;
buffer[3] = (byte)Http3SettingType.MaxHeaderListSize;
return(buffer.Slice(4 + integerLength).ToArray());
}
public const int MaximumEncodedFrameEnvelopeLength = 1 + VariableLengthIntegerHelper.MaximumEncodedLength; // Frame type + payload length.
/// <summary>
/// Reads two variable-length integers.
/// </summary>
public static bool TryReadIntegerPair(ReadOnlySpan <byte> buffer, out long a, out long b, out int bytesRead)
{
if (VariableLengthIntegerHelper.TryRead(buffer, out a, out int aLength))
{
buffer = buffer.Slice(aLength);
if (VariableLengthIntegerHelper.TryRead(buffer, out b, out int bLength))
{
bytesRead = aLength + bLength;
return(true);
}
}
b = 0;
bytesRead = 0;
return(false);
}
// 0 1 2 3
// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | Type (i) ...
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | Length (i) ...
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | Frame Payload (*) ...
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
public static bool TryWriteFrameEnvelope(Http3FrameType frameType, long payloadLength, Span <byte> buffer, out int bytesWritten)
{
Debug.Assert(VariableLengthIntegerHelper.GetByteCount((long)frameType) == 1, $"{nameof(TryWriteFrameEnvelope)} assumes {nameof(frameType)} will fit within a single byte varint.");
if (buffer.Length != 0)
{
buffer[0] = (byte)frameType;
buffer = buffer.Slice(1);
if (VariableLengthIntegerHelper.TryWrite(buffer, payloadLength, out int payloadLengthEncodedLength))
{
bytesWritten = payloadLengthEncodedLength + 1;
return(true);
}
}
bytesWritten = 0;
return(false);
}
/// <summary>
/// Reads the server's control stream.
/// </summary>
private async Task ProcessServerControlStreamAsync(QuicStream stream, ArrayBuffer buffer)
{
(Http3FrameType? frameType, long payloadLength) = await ReadFrameEnvelopeAsync().ConfigureAwait(false);
if (frameType == null)
{
// Connection closed prematurely, expected SETTINGS frame.
throw new Http3ConnectionException(Http3ErrorCode.ClosedCriticalStream);
}
if (frameType != Http3FrameType.Settings)
{
// Expected SETTINGS as first frame of control stream.
throw new Http3ConnectionException(Http3ErrorCode.MissingSettings);
}
await ProcessSettingsFrameAsync(payloadLength).ConfigureAwait(false);
while (true)
{
(frameType, payloadLength) = await ReadFrameEnvelopeAsync().ConfigureAwait(false);
switch (frameType)
{
case Http3FrameType.GoAway:
await ProcessGoAwayFameAsync(payloadLength).ConfigureAwait(false);
break;
case Http3FrameType.Settings:
// Only a single SETTINGS frame is supported.
throw new Http3ConnectionException(Http3ErrorCode.UnexpectedFrame);
case Http3FrameType.Headers:
case Http3FrameType.Data:
case Http3FrameType.MaxPushId:
case Http3FrameType.DuplicatePush:
// Servers should not send these frames to a control stream.
throw new Http3ConnectionException(Http3ErrorCode.UnexpectedFrame);
case Http3FrameType.PushPromise:
case Http3FrameType.CancelPush:
// Because we haven't sent any MAX_PUSH_ID frame, it is invalid to receive any push-related frames as they will all reference a too-large ID.
throw new Http3ConnectionException(Http3ErrorCode.IdError);
case null:
// End of stream reached. If we're shutting down, stop looping. Otherwise, this is an error (this stream should not be closed for life of connection).
bool shuttingDown;
lock (SyncObj)
{
shuttingDown = ShuttingDown;
}
if (!shuttingDown)
{
throw new Http3ConnectionException(Http3ErrorCode.ClosedCriticalStream);
}
return;
default:
await SkipUnknownPayloadAsync(frameType.GetValueOrDefault(), payloadLength).ConfigureAwait(false);
break;
}
}
async ValueTask <(Http3FrameType?frameType, long payloadLength)> ReadFrameEnvelopeAsync()
{
long frameType, payloadLength;
int bytesRead;
while (!Http3Frame.TryReadIntegerPair(buffer.ActiveSpan, out frameType, out payloadLength, out bytesRead))
{
buffer.EnsureAvailableSpace(VariableLengthIntegerHelper.MaximumEncodedLength * 2);
bytesRead = await stream.ReadAsync(buffer.AvailableMemory, CancellationToken.None).ConfigureAwait(false);
if (bytesRead != 0)
{
buffer.Commit(bytesRead);
}
else if (buffer.ActiveLength == 0)
{
// End of stream.
return(null, 0);
}
else
{
// Our buffer has partial frame data in it but not enough to complete the read: bail out.
throw new Http3ConnectionException(Http3ErrorCode.FrameError);
}
}
buffer.Discard(bytesRead);
return((Http3FrameType)frameType, payloadLength);
}
async ValueTask ProcessSettingsFrameAsync(long settingsPayloadLength)
{
if (settingsPayloadLength > MaximumSettingsPayloadLength)
{
if (NetEventSource.Log.IsEnabled())
{
Trace($"Received SETTINGS frame with {settingsPayloadLength} byte payload exceeding the {MaximumSettingsPayloadLength} byte maximum.");
}
throw new Http3ConnectionException(Http3ErrorCode.ExcessiveLoad);
}
while (settingsPayloadLength != 0)
{
long settingId, settingValue;
int bytesRead;
while (!Http3Frame.TryReadIntegerPair(buffer.ActiveSpan, out settingId, out settingValue, out bytesRead))
{
buffer.EnsureAvailableSpace(VariableLengthIntegerHelper.MaximumEncodedLength * 2);
bytesRead = await stream.ReadAsync(buffer.AvailableMemory, CancellationToken.None).ConfigureAwait(false);
if (bytesRead != 0)
{
buffer.Commit(bytesRead);
}
else
{
// Our buffer has partial frame data in it but not enough to complete the read: bail out.
throw new Http3ConnectionException(Http3ErrorCode.FrameError);
}
}
settingsPayloadLength -= bytesRead;
// Only support this single setting. Skip others.
if (settingId == (long)Http3SettingType.MaxHeaderListSize)
{
_maximumHeadersLength = (int)Math.Min(settingValue, int.MaxValue);
}
}
}
async ValueTask ProcessGoAwayFameAsync(long goawayPayloadLength)
{
long lastStreamId;
int bytesRead;
while (!VariableLengthIntegerHelper.TryRead(buffer.AvailableSpan, out lastStreamId, out bytesRead))
{
buffer.EnsureAvailableSpace(VariableLengthIntegerHelper.MaximumEncodedLength);
bytesRead = await stream.ReadAsync(buffer.AvailableMemory, CancellationToken.None).ConfigureAwait(false);
if (bytesRead != 0)
{
buffer.Commit(bytesRead);
}
else
{
// Our buffer has partial frame data in it but not enough to complete the read: bail out.
throw new Http3ConnectionException(Http3ErrorCode.FrameError);
}
}
buffer.Discard(bytesRead);
if (bytesRead != goawayPayloadLength)
{
// Frame contains unknown extra data after the integer.
throw new Http3ConnectionException(Http3ErrorCode.FrameError);
}
OnServerGoAway(lastStreamId);
}
async ValueTask SkipUnknownPayloadAsync(Http3FrameType frameType, long payloadLength)
{
if (payloadLength > MaximumUnknownFramePayloadLength)
{
Trace($"Received unknown frame type 0x{(long)frameType:x} with {payloadLength} byte payload exceeding the {MaximumUnknownFramePayloadLength} byte maximum.");
throw new Http3ConnectionException(Http3ErrorCode.ExcessiveLoad);
}
while (payloadLength != 0)
{
if (buffer.ActiveLength == 0)
{
int bytesRead = await stream.ReadAsync(buffer.AvailableMemory, CancellationToken.None).ConfigureAwait(false);
if (bytesRead != 0)
{
buffer.Commit(bytesRead);
}
else
{
// Our buffer has partial frame data in it but not enough to complete the read: bail out.
throw new Http3ConnectionException(Http3ErrorCode.FrameError);
}
}
long readLength = Math.Min(payloadLength, buffer.ActiveLength);
buffer.Discard((int)readLength);
payloadLength -= readLength;
}
}
}
/// <summary>
/// Routes a stream to an appropriate stream-type-specific processor
/// </summary>
private async Task ProcessServerStreamAsync(QuicStream stream)
{
try
{
await using (stream.ConfigureAwait(false))
using (var buffer = new ArrayBuffer(initialSize: 32, usePool: true))
{
if (stream.CanWrite)
{
// Server initiated bidirectional streams are either push streams or extensions, and we support neither.
throw new Http3ConnectionException(Http3ErrorCode.StreamCreationError);
}
int bytesRead;
try
{
bytesRead = await stream.ReadAsync(buffer.AvailableMemory, CancellationToken.None).ConfigureAwait(false);
}
catch (QuicStreamAbortedException)
{
// Treat identical to receiving 0. See below comment.
bytesRead = 0;
}
if (bytesRead == 0)
{
// https://quicwg.org/base-drafts/draft-ietf-quic-http.html#name-unidirectional-streams
// A sender can close or reset a unidirectional stream unless otherwise specified. A receiver MUST
// tolerate unidirectional streams being closed or reset prior to the reception of the unidirectional
// stream header.
return;
}
buffer.Commit(bytesRead);
// Stream type is a variable-length integer, but we only check the first byte. There is no known type requiring more than 1 byte.
switch (buffer.ActiveSpan[0])
{
case (byte)Http3StreamType.Control:
if (Interlocked.Exchange(ref _haveServerControlStream, 1) != 0)
{
// A second control stream has been received.
throw new Http3ConnectionException(Http3ErrorCode.StreamCreationError);
}
// Discard the stream type header.
buffer.Discard(1);
await ProcessServerControlStreamAsync(stream, buffer).ConfigureAwait(false);
return;
case (byte)Http3StreamType.QPackDecoder:
if (Interlocked.Exchange(ref _haveServerQpackDecodeStream, 1) != 0)
{
// A second QPack decode stream has been received.
throw new Http3ConnectionException(Http3ErrorCode.StreamCreationError);
}
// The stream must not be closed, but we aren't using QPACK right now -- ignore.
buffer.Dispose();
await stream.CopyToAsync(Stream.Null).ConfigureAwait(false);
return;
case (byte)Http3StreamType.QPackEncoder:
if (Interlocked.Exchange(ref _haveServerQpackEncodeStream, 1) != 0)
{
// A second QPack encode stream has been received.
throw new Http3ConnectionException(Http3ErrorCode.StreamCreationError);
}
// The stream must not be closed, but we aren't using QPACK right now -- ignore.
buffer.Dispose();
await stream.CopyToAsync(Stream.Null).ConfigureAwait(false);
return;
case (byte)Http3StreamType.Push:
// We don't support push streams.
// Because no maximum push stream ID was negotiated via a MAX_PUSH_ID frame, server should not have sent this. Abort the connection with H3_ID_ERROR.
throw new Http3ConnectionException(Http3ErrorCode.IdError);
default:
// Unknown stream type. Per spec, these must be ignored and aborted but not be considered a connection-level error.
if (NetEventSource.Log.IsEnabled())
{
// Read the rest of the integer, which might be more than 1 byte, so we can log it.
long unknownStreamType;
while (!VariableLengthIntegerHelper.TryRead(buffer.ActiveSpan, out unknownStreamType, out _))
{
buffer.EnsureAvailableSpace(VariableLengthIntegerHelper.MaximumEncodedLength);
bytesRead = await stream.ReadAsync(buffer.AvailableMemory, CancellationToken.None).ConfigureAwait(false);
if (bytesRead == 0)
{
unknownStreamType = -1;
break;
}
buffer.Commit(bytesRead);
}
NetEventSource.Info(this, $"Ignoring server-initiated stream of unknown type {unknownStreamType}.");
}
stream.AbortWrite((long)Http3ErrorCode.StreamCreationError);
return;
}
}
}
catch (Exception ex)
{
Abort(ex);
}
}
/// <summary>
/// Reads the server's control stream.
/// </summary>
private async Task ProcessServerControlStreamAsync(QuicStream stream, ArrayBuffer buffer)
{
using (buffer)
{
// Read the first frame of the control stream. Per spec:
// A SETTINGS frame MUST be sent as the first frame of each control stream.
(Http3FrameType? frameType, long payloadLength) = await ReadFrameEnvelopeAsync().ConfigureAwait(false);
if (frameType == null)
{
// Connection closed prematurely, expected SETTINGS frame.
throw new Http3ConnectionException(Http3ErrorCode.ClosedCriticalStream);
}
if (frameType != Http3FrameType.Settings)
{
throw new Http3ConnectionException(Http3ErrorCode.MissingSettings);
}
await ProcessSettingsFrameAsync(payloadLength).ConfigureAwait(false);
// Read subsequent frames.
while (true)
{
(frameType, payloadLength) = await ReadFrameEnvelopeAsync().ConfigureAwait(false);
switch (frameType)
{
case Http3FrameType.GoAway:
await ProcessGoAwayFameAsync(payloadLength).ConfigureAwait(false);
break;
case Http3FrameType.Settings:
// If an endpoint receives a second SETTINGS frame on the control stream, the endpoint MUST respond with a connection error of type H3_FRAME_UNEXPECTED.
throw new Http3ConnectionException(Http3ErrorCode.UnexpectedFrame);
case Http3FrameType.Headers:
case Http3FrameType.Data:
case Http3FrameType.MaxPushId:
case Http3FrameType.DuplicatePush:
// Servers should not send these frames to a control stream.
throw new Http3ConnectionException(Http3ErrorCode.UnexpectedFrame);
case Http3FrameType.PushPromise:
case Http3FrameType.CancelPush:
// Because we haven't sent any MAX_PUSH_ID frame, it is invalid to receive any push-related frames as they will all reference a too-large ID.
throw new Http3ConnectionException(Http3ErrorCode.IdError);
case null:
// End of stream reached. If we're shutting down, stop looping. Otherwise, this is an error (this stream should not be closed for life of connection).
bool shuttingDown;
lock (SyncObj)
{
shuttingDown = ShuttingDown;
}
if (!shuttingDown)
{
throw new Http3ConnectionException(Http3ErrorCode.ClosedCriticalStream);
}
return;
default:
await SkipUnknownPayloadAsync(frameType.GetValueOrDefault(), payloadLength).ConfigureAwait(false);
break;
}
}
}
async ValueTask <(Http3FrameType?frameType, long payloadLength)> ReadFrameEnvelopeAsync()
{
long frameType, payloadLength;
int bytesRead;
while (!Http3Frame.TryReadIntegerPair(buffer.ActiveSpan, out frameType, out payloadLength, out bytesRead))
{
buffer.EnsureAvailableSpace(VariableLengthIntegerHelper.MaximumEncodedLength * 2);
bytesRead = await stream.ReadAsync(buffer.AvailableMemory, CancellationToken.None).ConfigureAwait(false);
if (bytesRead != 0)
{
buffer.Commit(bytesRead);
}
else if (buffer.ActiveLength == 0)
{
// End of stream.
return(null, 0);
}
else
{
// Our buffer has partial frame data in it but not enough to complete the read: bail out.
throw new Http3ConnectionException(Http3ErrorCode.FrameError);
}
}
buffer.Discard(bytesRead);
return((Http3FrameType)frameType, payloadLength);
}
async ValueTask ProcessSettingsFrameAsync(long settingsPayloadLength)
{
while (settingsPayloadLength != 0)
{
long settingId, settingValue;
int bytesRead;
while (!Http3Frame.TryReadIntegerPair(buffer.ActiveSpan, out settingId, out settingValue, out bytesRead))
{
buffer.EnsureAvailableSpace(VariableLengthIntegerHelper.MaximumEncodedLength * 2);
bytesRead = await stream.ReadAsync(buffer.AvailableMemory, CancellationToken.None).ConfigureAwait(false);
if (bytesRead != 0)
{
buffer.Commit(bytesRead);
}
else
{
// Our buffer has partial frame data in it but not enough to complete the read: bail out.
throw new Http3ConnectionException(Http3ErrorCode.FrameError);
}
}
settingsPayloadLength -= bytesRead;
if (settingsPayloadLength < 0)
{
// An integer was encoded past the payload length.
// A frame payload that contains additional bytes after the identified fields or a frame payload that terminates before the end of the identified fields MUST be treated as a connection error of type H3_FRAME_ERROR.
throw new Http3ConnectionException(Http3ErrorCode.FrameError);
}
buffer.Discard(bytesRead);
// Only support this single setting. Skip others.
if (settingId == (long)Http3SettingType.MaxHeaderListSize)
{
_maximumHeadersLength = (int)Math.Min(settingValue, int.MaxValue);
}
}
}
async ValueTask ProcessGoAwayFameAsync(long goawayPayloadLength)
{
long lastStreamId;
int bytesRead;
while (!VariableLengthIntegerHelper.TryRead(buffer.AvailableSpan, out lastStreamId, out bytesRead))
{
buffer.EnsureAvailableSpace(VariableLengthIntegerHelper.MaximumEncodedLength);
bytesRead = await stream.ReadAsync(buffer.AvailableMemory, CancellationToken.None).ConfigureAwait(false);
if (bytesRead != 0)
{
buffer.Commit(bytesRead);
}
else
{
// Our buffer has partial frame data in it but not enough to complete the read: bail out.
throw new Http3ConnectionException(Http3ErrorCode.FrameError);
}
}
buffer.Discard(bytesRead);
if (bytesRead != goawayPayloadLength)
{
// Frame contains unknown extra data after the integer.
throw new Http3ConnectionException(Http3ErrorCode.FrameError);
}
OnServerGoAway(lastStreamId);
}
async ValueTask SkipUnknownPayloadAsync(Http3FrameType frameType, long payloadLength)
{
while (payloadLength != 0)
{
if (buffer.ActiveLength == 0)
{
int bytesRead = await stream.ReadAsync(buffer.AvailableMemory, CancellationToken.None).ConfigureAwait(false);
if (bytesRead != 0)
{
buffer.Commit(bytesRead);
}
else
{
// Our buffer has partial frame data in it but not enough to complete the read: bail out.
throw new Http3ConnectionException(Http3ErrorCode.FrameError);
}
}
long readLength = Math.Min(payloadLength, buffer.ActiveLength);
buffer.Discard((int)readLength);
payloadLength -= readLength;
}
}
}