From a51cdaacfcca9e8f3c2d5e72345ac82845d9d72c Mon Sep 17 00:00:00 2001
From: Tatsuhiro Tsujikawa <tatsuhiro.t@gmail.com>
Date: Thu, 29 Aug 2013 21:45:10 +0900
Subject: [PATCH] Add int return value to nghttp2_before_frame_send_callback

---
 lib/includes/nghttp2/nghttp2.h |  7 ++++++-
 lib/nghttp2_session.c          | 10 ++++++----
 src/shrpx_spdy_session.cc      |  9 +++++----
 3 files changed, 17 insertions(+), 9 deletions(-)

diff --git a/lib/includes/nghttp2/nghttp2.h b/lib/includes/nghttp2/nghttp2.h
index 2b85e913..e60b3368 100644
--- a/lib/includes/nghttp2/nghttp2.h
+++ b/lib/includes/nghttp2/nghttp2.h
@@ -850,8 +850,13 @@ typedef int (*nghttp2_on_data_recv_callback)
  * HEADERS and PUSH_PROMISE frame (see also
  * `nghttp2_session_get_stream_user_data()`), which is not assigned
  * when it was queued.
+ *
+ * The implementation of this function must return 0 if it
+ * succeeds. If nonzero is returned, it is treated as fatal error and
+ * `nghttp2_session_recv()` and `nghttp2_session_send()` functions
+ * immediately return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
  */
-typedef void (*nghttp2_before_frame_send_callback)
+typedef int (*nghttp2_before_frame_send_callback)
 (nghttp2_session *session, nghttp2_frame *frame, void *user_data);
 
 /**
diff --git a/lib/nghttp2_session.c b/lib/nghttp2_session.c
index 4d811121..791c090b 100644
--- a/lib/nghttp2_session.c
+++ b/lib/nghttp2_session.c
@@ -1496,10 +1496,12 @@ int nghttp2_session_send(nghttp2_session *session)
       /* Call before_send callback */
       if(item->frame_cat == NGHTTP2_CAT_CTRL &&
          session->callbacks.before_frame_send_callback) {
-        session->callbacks.before_frame_send_callback
-          (session,
-           nghttp2_outbound_item_get_ctrl_frame(item),
-           session->user_data);
+        if(session->callbacks.before_frame_send_callback
+           (session,
+            nghttp2_outbound_item_get_ctrl_frame(item),
+            session->user_data) != 0) {
+          return NGHTTP2_ERR_CALLBACK_FAILURE;
+        }
       }
     }
     data = session->aob.framebuf + session->aob.framebufoff;
diff --git a/src/shrpx_spdy_session.cc b/src/shrpx_spdy_session.cc
index 5221aef3..12c87ab1 100644
--- a/src/shrpx_spdy_session.cc
+++ b/src/shrpx_spdy_session.cc
@@ -945,9 +945,9 @@ int on_data_chunk_recv_callback(nghttp2_session *session,
 } // namespace
 
 namespace {
-void before_frame_send_callback(nghttp2_session *session,
-                                nghttp2_frame *frame,
-                                void *user_data)
+int before_frame_send_callback(nghttp2_session *session,
+                               nghttp2_frame *frame,
+                               void *user_data)
 {
   if(frame->hd.type == NGHTTP2_HEADERS &&
      frame->headers.cat == NGHTTP2_HCAT_REQUEST) {
@@ -956,7 +956,7 @@ void before_frame_send_callback(nghttp2_session *session,
     if(!sd || !sd->dconn) {
       nghttp2_submit_rst_stream(session, frame->hd.stream_id,
                                 NGHTTP2_CANCEL);
-      return;
+      return 0;
     }
     auto downstream = sd->dconn->get_downstream();
     if(downstream) {
@@ -965,6 +965,7 @@ void before_frame_send_callback(nghttp2_session *session,
       nghttp2_submit_rst_stream(session, frame->hd.stream_id, NGHTTP2_CANCEL);
     }
   }
+  return 0;
 }
 } // namespace