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

[Roman Arutyunyan]

# 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;
+    }
+
+    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);
+    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,