[PATCH 4 of 4] HTTP/2: don't send SETTINGS ACK before already queued DATA frames

[Piotr Sikora]

# HG changeset patch
# User Piotr Sikora <piotrsikora at google.com>
# Date 1493073310 25200
#      Mon Apr 24 15:35:10 2017 -0700
# Node ID 3624fa075acac110a08c0f1c928c545a58c5801f
# Parent  b8d7f4a4d5abb4a27a772910358e263d49c618ef
HTTP/2: don't send SETTINGS ACK before already queued DATA frames.

Previously, SETTINGS ACK was sent immediately upon receipt of SETTINGS
frame, before already queued DATA frames created using old SETTINGS.

This incorrect behavior was source of interoperability issues, because
peers rely on the fact that new SETTINGS are in effect after receiving
SETTINGS ACK.

Reported by Feng Li.

Signed-off-by: Piotr Sikora <piotrsikora at google.com>

diff -r b8d7f4a4d5ab -r 3624fa075aca src/http/v2/ngx_http_v2.c
--- a/src/http/v2/ngx_http_v2.c
+++ b/src/http/v2/ngx_http_v2.c
@@ -2043,7 +2043,7 @@ ngx_http_v2_state_settings_params(ngx_ht
         return ngx_http_v2_connection_error(h2c, NGX_HTTP_V2_INTERNAL_ERROR);
     }
 
-    ngx_http_v2_queue_blocked_frame(h2c, frame);
+    ngx_http_v2_queue_ordered_frame(h2c, frame);
 
     if (adjustment) {
         if (ngx_http_v2_adjust_windows(h2c, adjustment) != NGX_OK) {
diff -r b8d7f4a4d5ab -r 3624fa075aca src/http/v2/ngx_http_v2.h
--- a/src/http/v2/ngx_http_v2.h
+++ b/src/http/v2/ngx_http_v2.h
@@ -261,6 +261,15 @@ ngx_http_v2_queue_blocked_frame(ngx_http
 }
 
 
+static ngx_inline void
+ngx_http_v2_queue_ordered_frame(ngx_http_v2_connection_t *h2c,
+    ngx_http_v2_out_frame_t *frame)
+{
+    frame->next = h2c->last_out;
+    h2c->last_out = frame;
+}
+
+
 void ngx_http_v2_init(ngx_event_t *rev);
 void ngx_http_v2_request_headers_init(void);