Method rcv_window_update_frame

src/proxy/http2/Http2ConnectionState.cc:909–1002

}

Http2Error
Http2ConnectionState::rcv_window_update_frame(const Http2Frame &frame)
{
  char                buf[HTTP2_WINDOW_UPDATE_LEN];
  uint32_t            size;
  const Http2StreamId stream_id = frame.header().streamid;

  //  A WINDOW_UPDATE frame with a length other than 4 octets MUST be
  //  treated as a connection error of type FRAME_SIZE_ERROR.
  if (frame.header().length != HTTP2_WINDOW_UPDATE_LEN) {
    Http2StreamDebug(this->session, stream_id, "Received WINDOW_UPDATE frame - length incorrect");
    return Http2Error(Http2ErrorClass::HTTP2_ERROR_CLASS_CONNECTION, Http2ErrorCode::HTTP2_ERROR_FRAME_SIZE_ERROR,
                      "window update bad length");
  }

  frame.reader()->memcpy(buf, sizeof(buf), 0);
  http2_parse_window_update(make_iovec(buf, sizeof(buf)), size);

  // A receiver MUST treat the receipt of a WINDOW_UPDATE frame with a flow
  // control window increment of 0 as a connection error of type PROTOCOL_ERROR;
  if (size == 0) {
    if (stream_id == HTTP2_CONNECTION_CONTROL_STREAM) {
      return Http2Error(Http2ErrorClass::HTTP2_ERROR_CLASS_CONNECTION, Http2ErrorCode::HTTP2_ERROR_PROTOCOL_ERROR,
                        "window update length=0 and id=0");
    } else {
      return Http2Error(Http2ErrorClass::HTTP2_ERROR_CLASS_STREAM, Http2ErrorCode::HTTP2_ERROR_PROTOCOL_ERROR,
                        "window update length=0");
    }
  }

  if (stream_id == HTTP2_CONNECTION_CONTROL_STREAM) {
    // Connection level window update
    Http2StreamDebug(this->session, stream_id, "Received WINDOW_UPDATE frame - updated to: %zd delta: %u",
                     (this->get_peer_rwnd() + size), size);

    // A sender MUST NOT allow a flow-control window to exceed 2^31-1
    // octets.  If a sender receives a WINDOW_UPDATE that causes a flow-
    // control window to exceed this maximum, it MUST terminate either the
    // stream or the connection, as appropriate.  For streams, the sender
    // sends a RST_STREAM with an error code of FLOW_CONTROL_ERROR; for the
    // connection, a GOAWAY frame with an error code of FLOW_CONTROL_ERROR
    // is sent.
    if (size > HTTP2_MAX_WINDOW_SIZE - this->get_peer_rwnd()) {
      return Http2Error(Http2ErrorClass::HTTP2_ERROR_CLASS_CONNECTION, Http2ErrorCode::HTTP2_ERROR_FLOW_CONTROL_ERROR,
                        "window update too big");
    }

    auto error = this->increment_peer_rwnd(size);
    if (error != Http2ErrorCode::HTTP2_ERROR_NO_ERROR) {
      return Http2Error(Http2ErrorClass::HTTP2_ERROR_CLASS_CONNECTION, error, "Erroneous client window update");
    }
    this->restart_streams();
  } else {
    // Stream level window update
    Http2Stream *stream = this->find_stream(stream_id);

    if (stream == nullptr) {
      if (this->is_valid_streamid(stream_id)) {