Is onInvalidFrame() method in http2/codec_impl.cc preventing GO_AWAY frame from being sent for protocol errors?

Description:

I have a case where I am not receiving a GO_AWAY frame when sending an incorrect stream_id in the HEADER frame. From what I can tell, the session_handle_invalid_connection() method inside the nghttp2_session class is invoking the onInvalidFrame() callback inside the http2/codec_impl.cc class with NGHTTP2_ERR_PROTO as the error code. However, since the onInvalidFrame() method is not returning 0, the GO_AWAY frame is never sent. Is this normal?

session_handle_invalid_connection() method:

static int session_handle_invalid_connection(nghttp2_session *session,
                                             nghttp2_frame *frame,
                                             int lib_error_code,
                                             const char *reason) {
  if (session->callbacks.on_invalid_frame_recv_callback) {
    if (session->callbacks.on_invalid_frame_recv_callback(
            session, frame, lib_error_code, session->user_data) != 0) {
      return NGHTTP2_ERR_CALLBACK_FAILURE;
    }
  }
  return nghttp2_session_terminate_session_with_reason(
      session, get_error_code_from_lib_error_code(lib_error_code), reason);
}

onInvalidFrame() callback:

int ConnectionImpl::onInvalidFrame(int32_t stream_id, int error_code) {
  ENVOY_CONN_LOG(debug, "invalid frame: {} on stream {}", connection_, nghttp2_strerror(error_code),
                 stream_id);

  if (error_code == NGHTTP2_ERR_HTTP_HEADER || error_code == NGHTTP2_ERR_HTTP_MESSAGING) {
    stats_.rx_messaging_error_.inc();

    if (stream_error_on_invalid_http_messaging_) {
      // The stream is about to be closed due to an invalid header or messaging. Don't kill the
      // entire connection if one stream has bad headers or messaging.
      StreamImpl* stream = getStream(stream_id);
      if (stream != nullptr) {
        // See comment below in onStreamClose() for why we do this.
        stream->reset_due_to_messaging_error_ = true;
      }
      return 0;
    }
  }

  // Cause dispatch to return with an error code.
  return NGHTTP2_ERR_CALLBACK_FAILURE;
}

Snippet of backtrace:

#0 Envoy::Http::Http2::ConnectionImpl::onInvalidFrame (this=0x55555a0329b8, stream_id=2, error_code=-505) at external/envoy/source/common/http/http2/codec_impl.cc:636 #1 0x0000555556a43149 in Envoy::Http::Http2::ConnectionImpl::Http2Callbacks::<lambda(nghttp2_session*, const nghttp2_frame*, int, void*)>::operator()(nghttp2_session , const nghttp2_frame , int, void ) const (__closure=0x0, frame=0x555559d7d3a0, error_code=-505, user_data=0x55555a0329b8) at external/envoy/source/common/http/http2/codec_impl.cc:1009 #2 0x0000555556a43181 in Envoy::Http::Http2::ConnectionImpl::Http2Callbacks::<lambda(nghttp2_session, const nghttp2_frame, int, void)>::_FUN(nghttp2_session *, const nghttp2_frame *, int, void *) () at external/envoy/source/common/http/http2/codec_impl.cc:1010 #3 0x0000555556a5e339 in session_handle_invalid_connection (session=0x555559d7d200, frame=0x555559d7d3a0, lib_error_code=-505, reason=0x555557dcbed0 "request HEADERS: client received request") at /home/ekishpa/.cache/bazel/_bazel_ekishpa/85e9f933f608b792c07cb9f0a32a9492/sandbox/linux-sandbox/1/execroot/adc/external/com_github_nghttp2_nghttp2/lib/nghttp2_session.c:3518 #4 0x0000555556a5e392 in session_inflate_handle_invalid_connection (session=0x555559d7d200, frame=0x555559d7d3a0, lib_error_code=-505, reason=0x555557dcbed0 "request HEADERS: client received request") at /home/ekishpa/.cache/bazel/_bazel_ekishpa/85e9f933f608b792c07cb9f0a32a9492/sandbox/linux-sandbox/1/execroot/adc/external/com_github_nghttp2_nghttp2/lib/nghttp2_session.c:3532 #5 0x0000555556a5ec51 in nghttp2_session_on_request_headers_received (session=0x555559d7d200, frame=0x555559d7d3a0) at /home/ekishpa/.cache/bazel/_bazel_ekishpa/85e9f933f608b792c07cb9f0a32a9492/sandbox/linux-sandbox/1/execroot/adc/external/com_github_nghttp2_nghttp2/lib/nghttp2_session.c:3833 #6 0x0000555556a5f2e8 in session_process_headers_frame (session=0x555559d7d200) at /home/ekishpa/.cache/bazel/_bazel_ekishpa/85e9f933f608b792c07cb9f0a32a9492/sandbox/linux-sandbox/1/execroot/adc/external/com_github_nghttp2_nghttp2/lib/nghttp2_session.c:4060 #7 0x0000555556a62015 in nghttp2_session_mem_recv (session=0x555559d7d200, in=0x55555a07f03a "\210@\fcontent-type\020application/grpc@\024grpc-accept-encoding\025identity,deflate,gzip@\017accept-encoding\ridentity,gzip", inlen=487) at /home/ekishpa/.cache/bazel/_bazel_ekishpa/85e9f933f608b792c07cb9f0a32a9492/sandbox/linux-sandbox/1/execroot/adc/external/com_github_nghttp2_nghttp2/lib/nghttp2_session.c:5595 #8 0x0000555556a3f3d9 in Envoy::Http::Http2::ConnectionImpl::dispatch (this=0x55555a0329b8, data=...) at external/envoy/source/common/http/http2/codec_impl.cc:412