[PATCH 1 of 3] QUIC: set stream error flag on reset

[Sergey Kandaurov]

> On 5 Jan 2023, at 19:31, Roman Arutyunyan <arut at nginx.com> wrote:
> 
> src/event/quic/ngx_event_quic_streams.c |  14 ++++++++++++--
> 1 files changed, 12 insertions(+), 2 deletions(-)
> 
> 
> # HG changeset patch
> # User Roman Arutyunyan <arut at nginx.com>
> # Date 1672932528 -14400
> #      Thu Jan 05 19:28:48 2023 +0400
> # Branch quic
> # Node ID 480300240a4ea0e03e656039b9498c78b5adc21e
> # Parent  987bee4363d10895f4bd1a40fc4347c49763e90f
> QUIC: set stream error flag on reset.
> 
> Now, when RESET_STREAM is sent or received, or when streams are closed, stream
> connection error flag is set.  Previously, only stream state was changed, which
> resulted in setting the error flag only after calling
> recv()/send()/send_chain().  However, there are cases when none of these
> functions is called, but it's still important to know if the stream is being
> closed.  For example, when an HTTP/3 request stream is blocked on insert count,
> receiving RESET_STREAM should trigger stream closure, which was not the case.

To make stream closure work when receiving RESET_STREAM, for a stream that
blocks on insert count, the read event should be active, so it is posted.
It could be made active with ngx_handle_read_event(), but since rev->ready
remains set, this prevents from setting rev->active = 1.

> 
> The change also fixes ngx_http_test_reading() and
> ngx_http_upstream_check_broken_connection() with QUIC streams.
> 
> diff --git a/src/event/quic/ngx_event_quic_streams.c b/src/event/quic/ngx_event_quic_streams.c
> --- a/src/event/quic/ngx_event_quic_streams.c
> +++ b/src/event/quic/ngx_event_quic_streams.c
> @@ -203,6 +203,9 @@ ngx_quic_close_streams(ngx_connection_t 
>             continue;
>         }
> 
> +        sc->read->error = 1;
> +        sc->write->error = 1;
> +
>         ngx_quic_set_event(sc->read);
>         ngx_quic_set_event(sc->write);
> 
> @@ -245,6 +248,10 @@ ngx_quic_do_reset_stream(ngx_quic_stream
>     qs->send_state = NGX_QUIC_STREAM_SEND_RESET_SENT;
>     qs->send_final_size = qs->send_offset;
> 
> +    if (qs->connection) {
> +        qs->connection->write->error = 1;
> +    }
> +
>     pc = qs->parent;
>     qc = ngx_quic_get_connection(pc);
> 
> @@ -797,7 +804,6 @@ ngx_quic_stream_recv(ngx_connection_t *c
>         || qs->recv_state == NGX_QUIC_STREAM_RECV_RESET_READ)
>     {
>         qs->recv_state = NGX_QUIC_STREAM_RECV_RESET_READ;
> -        rev->error = 1;
>         return NGX_ERROR;
>     }
> 
> @@ -1375,6 +1381,7 @@ ngx_int_t
> ngx_quic_handle_reset_stream_frame(ngx_connection_t *c,
>     ngx_quic_header_t *pkt, ngx_quic_reset_stream_frame_t *f)
> {
> +    ngx_event_t            *rev;
>     ngx_quic_stream_t      *qs;
>     ngx_quic_connection_t  *qc;
> 
> @@ -1431,7 +1438,10 @@ ngx_quic_handle_reset_stream_frame(ngx_c
>         return ngx_quic_close_stream(qs);
>     }
> 
> -    ngx_quic_set_event(qs->connection->read);
> +    rev = qs->connection->read;
> +    rev->error = 1;
> +
> +    ngx_quic_set_event(rev);
> 
>     return NGX_OK;
> }

-- 
Sergey Kandaurov