Fix DATA is not consumed if nghttp2_http_on_data_chunk failed

This commit fixes the bug that DATA is not consumed if
nghttp2_http_on_data_chunk is failed.  It also simplify the handling
of missing stream in NGHTTP2_IB_READ_DATA state.

lib/nghttp2_session.c

@@ -5739,6 +5739,14 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
 
       break;
     case NGHTTP2_IB_READ_DATA:
+      stream = nghttp2_session_get_stream(session, iframe->frame.hd.stream_id);
+
+      if (!stream) {
+        busy = 1;
+        iframe->state = NGHTTP2_IB_IGN_DATA;
+        break;
+      }
+
       DEBUGF(fprintf(stderr, "recv: [IB_READ_DATA]\n"));
 
       readlen = inbound_frame_payload_readlen(iframe, in, last);
@@ -5756,9 +5764,6 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
           return rv;
         }
 
-        stream =
-            nghttp2_session_get_stream(session, iframe->frame.hd.stream_id);
-        if (stream) {
         rv = session_update_recv_stream_window_size(
             session, stream, readlen,
             iframe->payloadleft ||
@@ -5787,9 +5792,18 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
         if (data_readlen > 0) {
           if (session_enforce_http_messaging(session)) {
             if (nghttp2_http_on_data_chunk(stream, data_readlen) != 0) {
-                rv = nghttp2_session_add_rst_stream(session,
-                                                    iframe->frame.hd.stream_id,
-                                                    NGHTTP2_PROTOCOL_ERROR);
+              if (session->opt_flags & NGHTTP2_OPTMASK_NO_AUTO_WINDOW_UPDATE) {
+                /* Consume all data for connection immediately here */
+                rv = session_update_connection_consumed_size(session,
+                                                             data_readlen);
+
+                if (nghttp2_is_fatal(rv)) {
+                  return rv;
+                }
+              }
+
+              rv = nghttp2_session_add_rst_stream(
+                  session, iframe->frame.hd.stream_id, NGHTTP2_PROTOCOL_ERROR);
               if (nghttp2_is_fatal(rv)) {
                 return rv;
               }
@@ -5811,15 +5825,6 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
             }
           }
         }
-        } else if (session->opt_flags & NGHTTP2_OPTMASK_NO_AUTO_WINDOW_UPDATE) {
-          /* stream was closed or does not exist.  Consume all data
-             for connection immediately here */
-          rv = session_update_connection_consumed_size(session, readlen);
-
-          if (nghttp2_is_fatal(rv)) {
-            return rv;
-          }
-        }
       }
 
       if (iframe->payloadleft) {