[PATCH 2 of 2] QUIC: handle DATA_BLOCKED frame from client

[Vladimir Homutov]

On Wed, Nov 17, 2021 at 10:31:02AM +0300, Roman Arutyunyan wrote:
> # HG changeset patch
> # User Roman Arutyunyan <arut at nginx.com>
> # Date 1637086755 -10800
> #      Tue Nov 16 21:19:15 2021 +0300
> # Branch quic
> # Node ID 0fb2613594f6bd8dd8f07a30c69900866b573158
> # Parent  4e3a7fc0533192f51a01042a1e9dd2b595881420
> QUIC: handle DATA_BLOCKED frame from client.
>
> Previously the frame was not handled and connection was closed with an error.
> Now, after receiving this frame, global flow control is updated and new
> flow control credit is sent to client.
>
> diff --git a/src/event/quic/ngx_event_quic.c b/src/event/quic/ngx_event_quic.c
> --- a/src/event/quic/ngx_event_quic.c
> +++ b/src/event/quic/ngx_event_quic.c
> @@ -1252,6 +1252,17 @@ ngx_quic_handle_frames(ngx_connection_t
>
>              break;
>
> +        case NGX_QUIC_FT_DATA_BLOCKED:
> +
> +            if (ngx_quic_handle_data_blocked_frame(c, pkt,
> +                                                   &frame.u.data_blocked)
> +                != NGX_OK)
> +            {
> +                return NGX_ERROR;
> +            }
> +
> +            break;
> +
>          case NGX_QUIC_FT_STREAM_DATA_BLOCKED:
>
>              if (ngx_quic_handle_stream_data_blocked_frame(c, pkt,
> 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
> @@ -32,6 +32,7 @@ static void ngx_quic_stream_cleanup_hand
>  static ngx_int_t ngx_quic_control_flow(ngx_connection_t *c, uint64_t last);
>  static ngx_int_t ngx_quic_update_flow(ngx_connection_t *c, uint64_t last);
>  static ngx_int_t ngx_quic_update_max_stream_data(ngx_connection_t *c);
> +static ngx_int_t ngx_quic_update_max_data(ngx_connection_t *c);
>
>
>  ngx_connection_t *
> @@ -1188,6 +1189,14 @@ ngx_quic_handle_streams_blocked_frame(ng
>
>
>  ngx_int_t
> +ngx_quic_handle_data_blocked_frame(ngx_connection_t *c,
> +    ngx_quic_header_t *pkt, ngx_quic_data_blocked_frame_t *f)
> +{
> +    return ngx_quic_update_max_data(c);
> +}
> +
> +
> +ngx_int_t
>  ngx_quic_handle_stream_data_blocked_frame(ngx_connection_t *c,
>      ngx_quic_header_t *pkt, ngx_quic_stream_data_blocked_frame_t *f)
>  {
> @@ -1544,7 +1553,6 @@ ngx_quic_update_flow(ngx_connection_t *c
>      uint64_t                len;
>      ngx_event_t            *rev;
>      ngx_connection_t       *pc;
> -    ngx_quic_frame_t       *frame;
>      ngx_quic_stream_t      *qs;
>      ngx_quic_connection_t  *qc;
>
> @@ -1577,22 +1585,9 @@ ngx_quic_update_flow(ngx_connection_t *c
>      if (qc->streams.recv_max_data
>          <= qc->streams.recv_offset + qc->streams.recv_window / 2)
>      {
> -        qc->streams.recv_max_data = qc->streams.recv_offset
> -                                    + qc->streams.recv_window;
> -
> -        ngx_log_debug1(NGX_LOG_DEBUG_EVENT, pc->log, 0,
> -                       "quic flow update md:%uL", qc->streams.recv_max_data);
> -
> -        frame = ngx_quic_alloc_frame(pc);
> -        if (frame == NULL) {
> +        if (ngx_quic_update_max_data(pc) != NGX_OK) {
>              return NGX_ERROR;
>          }
> -
> -        frame->level = ssl_encryption_application;
> -        frame->type = NGX_QUIC_FT_MAX_DATA;
> -        frame->u.max_data.max_data = qc->streams.recv_max_data;
> -
> -        ngx_quic_queue_frame(qc, frame);
>      }
>
>      return NGX_OK;
> @@ -1637,6 +1632,41 @@ ngx_quic_update_max_stream_data(ngx_conn
>  }
>
>
> +static ngx_int_t
> +ngx_quic_update_max_data(ngx_connection_t *c)
> +{
> +    uint64_t                recv_max_data;
> +    ngx_quic_frame_t       *frame;
> +    ngx_quic_connection_t  *qc;
> +
> +    qc = ngx_quic_get_connection(c);
> +
> +    recv_max_data = qc->streams.recv_offset + qc->streams.recv_window;
> +
> +    if (qc->streams.recv_max_data == recv_max_data) {
> +        return NGX_OK;
> +    }

same question as in previous patch; logic is the same;

> +
> +    qc->streams.recv_max_data = recv_max_data;
> +
> +    ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0,
> +                   "quic flow update md:%uL", qc->streams.recv_max_data);
> +
> +    frame = ngx_quic_alloc_frame(c);

looks like the same issue as in the previous patch - should be pc here

> +    if (frame == NULL) {
> +        return NGX_ERROR;
> +    }
> +
> +    frame->level = ssl_encryption_application;
> +    frame->type = NGX_QUIC_FT_MAX_DATA;
> +    frame->u.max_data.max_data = qc->streams.recv_max_data;
> +
> +    ngx_quic_queue_frame(qc, frame);
> +
> +    return NGX_OK;
> +}
> +
> +
>  ngx_int_t
>  ngx_quic_handle_read_event(ngx_event_t *rev, ngx_uint_t flags)
>  {
> diff --git a/src/event/quic/ngx_event_quic_streams.h b/src/event/quic/ngx_event_quic_streams.h
> --- a/src/event/quic/ngx_event_quic_streams.h
> +++ b/src/event/quic/ngx_event_quic_streams.h
> @@ -20,6 +20,8 @@ ngx_int_t ngx_quic_handle_max_data_frame
>      ngx_quic_max_data_frame_t *f);
>  ngx_int_t ngx_quic_handle_streams_blocked_frame(ngx_connection_t *c,
>      ngx_quic_header_t *pkt, ngx_quic_streams_blocked_frame_t *f);
> +ngx_int_t ngx_quic_handle_data_blocked_frame(ngx_connection_t *c,
> +    ngx_quic_header_t *pkt, ngx_quic_data_blocked_frame_t *f);
>  ngx_int_t ngx_quic_handle_stream_data_blocked_frame(ngx_connection_t *c,
>      ngx_quic_header_t *pkt, ngx_quic_stream_data_blocked_frame_t *f);
>  ngx_int_t ngx_quic_handle_max_stream_data_frame(ngx_connection_t *c,