http/3: transfer is still ongoing on quic stream when cancel the http3 stream on which connection has other http/3 streams

[yiweiYoung]

I did this

i make http/3 requests on easy handle, then add to multi handle. pesudo code like this

• init multi handle
• • init easy handle1, then add to multi
• multi poll(such as 100ms)
• • init easy handle2, then add to multi, handle2 will resue quic connection
• multi poll(for such as 100ms)
• remove easy handle1
• multi poll(for such as 10s)
• ...

I expected the following

after remove easy handle1, the http/3 stream is closed but quic stream is still opened. why?

actually, quic stream0 is still transer data. i find this from the source code at curl_ngtcp2.c

Q why quic stream is remain opened when we shutdown http/3 stream

static void h3_data_done(struct Curl_cfilter *cf, struct Curl_easy *data)
{
  struct cf_ngtcp2_ctx *ctx = cf->ctx;
  struct h3_stream_ctx *stream = H3_STREAM_CTX(data);

  (void)cf;
  if(stream) {
    CURL_TRC_CF(data, cf, "[%"PRId64"] easy handle is done", stream->id);
    if(ctx->h3conn && !stream->closed) {
    /* shutdown http/3 stream, but quic stream is open, why not */
      nghttp3_conn_shutdown_stream_read(ctx->h3conn, stream->id);
      nghttp3_conn_close_stream(ctx->h3conn, stream->id,
                                NGHTTP3_H3_REQUEST_CANCELLED);
      nghttp3_conn_set_stream_user_data(ctx->h3conn, stream->id, NULL);
      ngtcp2_conn_set_stream_user_data(ctx->qconn, stream->id, NULL);
      stream->closed = TRUE;
    }

    Curl_bufq_free(&stream->sendbuf);
    Curl_h1_req_parse_free(&stream->h1);
    free(stream);
    H3_STREAM_LCTX(data) = NULL;
  }
}

...

static CURLcode cf_ngtcp2_data_event(struct Curl_cfilter *cf,
                                     struct Curl_easy *data,
                                     int event, int arg1, void *arg2)
  case CF_CTRL_DATA_DETACH:
    h3_data_done(cf, data);
    break;

curl/libcurl version

curl version: libcurl/8.7.0-DEV quictls/1.1.1s zlib/1.2.11 ngtcp2/1.4.0 nghttp3/1.2.0

operating system

Darwin B-92RGMD6R-1918.local 22.5.0 Darwin Kernel Version 22.5.0: Thu Jun 8 22:22:22 PDT 2023; root:xnu-8796.121.3~7/RELEASE_X86_64 x86_64

[icing]

Thanks for the report. This seems to point to a misunderstanding by us how the nghttp3+ngtcp2 APIs work here.

PR #13562 should fix this for you. If you are able to build that and verify that is works for you, that'd be great!

[icing]

The fix has been merged into master now.

[bagder]

@yiweiYoung if you try curl from git master, does it behave better for you?

[yiweiYoung]

thanks, it is OK now