Apply initiated SETTINGS changes on reception of ACK

lib/includes/nghttp2/nghttp2.h

@@ -127,6 +127,13 @@ typedef struct {
  */
 #define NGHTTP2_INITIAL_CONNECTION_WINDOW_SIZE ((1 << 16) - 1)
 
+/**
+ * @macro
+ *
+ * The maximum header table size.
+ */
+#define NGHTTP2_MAX_HEADER_TABLE_SIZE (1 << 16)
+
 /**
  * @macro
  *
@@ -262,6 +269,11 @@ typedef enum {
    * Callback was paused by the application
    */
   NGHTTP2_ERR_PAUSE = -526,
+  /**
+   * There are too many in-flight SETTING frame and no more
+   * transmission of SETTINGS is allowed.
+   */
+  NGHTTP2_ERR_TOO_MANY_INFLIGHT_SETTINGS = -527,
   /**
    * The errors < :enum:`NGHTTP2_ERR_FATAL` mean that the library is
    * under unexpected condition and cannot process any further data
@@ -379,9 +391,9 @@ typedef enum {
    */
   NGHTTP2_FLAG_END_PUSH_PROMISE = 0x4,
   /**
-   * The PONG flag.
+   * The ACK flag.
    */
-  NGHTTP2_FLAG_PONG = 0x1
+  NGHTTP2_FLAG_ACK = 0x1
 } nghttp2_flag;
 
 /**

lib/nghttp2_frame.c

@@ -106,12 +106,11 @@ void nghttp2_frame_rst_stream_free(nghttp2_rst_stream *frame)
 {}
 
 
-void nghttp2_frame_settings_init(nghttp2_settings *frame,
+void nghttp2_frame_settings_init(nghttp2_settings *frame, uint8_t flags,
                                  nghttp2_settings_entry *iv, size_t niv)
 {
   memset(frame, 0, sizeof(nghttp2_settings));
-  nghttp2_frame_set_hd(&frame->hd, niv*8, NGHTTP2_SETTINGS, NGHTTP2_FLAG_NONE,
-                       0);
+  nghttp2_frame_set_hd(&frame->hd, niv*8, NGHTTP2_SETTINGS, flags, 0);
   frame->niv = niv;
   frame->iv = iv;
 }

lib/nghttp2_frame.h

@@ -470,7 +470,7 @@ void nghttp2_frame_push_promise_free(nghttp2_push_promise *frame);
  * ownership of |iv|, so caller must not free it. The |flags| are
  * bitwise-OR of one or more of nghttp2_settings_flag.
  */
-void nghttp2_frame_settings_init(nghttp2_settings *frame,
+void nghttp2_frame_settings_init(nghttp2_settings *frame, uint8_t flags,
                                  nghttp2_settings_entry *iv, size_t niv);
 
 void nghttp2_frame_settings_free(nghttp2_settings *frame);

lib/nghttp2_session.h

@@ -188,6 +188,13 @@ struct nghttp2_session {
   /* Settings value of the local endpoint. */
   uint32_t local_settings[NGHTTP2_SETTINGS_MAX+1];
 
+  /* In-flight SETTINGS values. NULL does not necessarily mean there
+     is no in-flight SETTINGS. */
+  nghttp2_settings_entry *inflight_iv;
+  /* The number of entries in |inflight_iv|. -1 if there is no
+     in-flight SETTINGS. */
+  ssize_t inflight_niv;
+
   /* Option flags. This is bitwise-OR of 0 or more of nghttp2_optmask. */
   uint32_t opt_flags;
 
@@ -295,6 +302,18 @@ int nghttp2_session_add_window_update(nghttp2_session *session, uint8_t flags,
                                       int32_t stream_id,
                                       int32_t window_size_increment);
 
+/*
+ * Adds SETTINGS frame.
+ *
+ * This function returns 0 if it succeeds, or one of the following
+ * negative error codes:
+ *
+ * NGHTTP2_ERR_NOMEM
+ *     Out of memory.
+ */
+int nghttp2_session_add_settings(nghttp2_session *session, uint8_t flags,
+                                 const nghttp2_settings_entry *iv, size_t niv);
+
 /*
  * Creates new stream in |session| with stream ID |stream_id|,
  * priority |pri| and flags |flags|. NGHTTP2_FLAG_END_STREAM flag is
@@ -386,19 +405,33 @@ int nghttp2_session_on_priority_received(nghttp2_session *session,
  * Called when RST_STREAM is received, assuming |frame| is properly
  * initialized.
  *
- * This function returns 0 and never fail.
+ * This function returns 0 if it succeeds, or one the following
+ * negative error codes:
+ *
+ * TBD
  */
 int nghttp2_session_on_rst_stream_received(nghttp2_session *session,
                                            nghttp2_frame *frame);
 
 /*
  * Called when SETTINGS is received, assuming |frame| is properly
- * initialized.
+ * initialized. If |noack| is non-zero, SETTINGS with ACK will not be
+ * submitted. If |frame| has NGHTTP2_FLAG_ACK flag set, no SETTINGS
+ * with ACK will not be submitted regardless of |noack|.
  *
- * This function returns 0 and never fail.
+ * This function returns 0 if it succeeds, or one the following
+ * negative error codes:
+ *
+ * NGHTTP2_ERR_NOMEM
+ *     Out of memory
+ * NGHTTP2_ERR_PAUSE
+ *     Callback function returns NGHTTP2_ERR_PAUSE
+ * NGHTTP2_ERR_CALLBACK_FAILURE
+ *     The read_callback failed
  */
 int nghttp2_session_on_settings_received(nghttp2_session *session,
-                                         nghttp2_frame *frame);
+                                         nghttp2_frame *frame,
+                                         int noack);
 
 /*
  * Called when PUSH_PROMISE is received, assuming |frame| is properly

lib/nghttp2_submit.c

@@ -209,39 +209,7 @@ int nghttp2_submit_goaway(nghttp2_session *session, uint8_t flags,
 int nghttp2_submit_settings(nghttp2_session *session, uint8_t flags,
                             const nghttp2_settings_entry *iv, size_t niv)
 {
-  nghttp2_frame *frame;
-  nghttp2_settings_entry *iv_copy;
-  int r;
-  if(!nghttp2_iv_check(iv, niv,
-                       session->local_settings
-                       [NGHTTP2_SETTINGS_FLOW_CONTROL_OPTIONS])) {
-    return NGHTTP2_ERR_INVALID_ARGUMENT;
-  }
-  frame = malloc(sizeof(nghttp2_frame));
-  if(frame == NULL) {
-    return NGHTTP2_ERR_NOMEM;
-  }
-  iv_copy = nghttp2_frame_iv_copy(iv, niv);
-  if(iv_copy == NULL) {
-    free(frame);
-    return NGHTTP2_ERR_NOMEM;
-  }
-  nghttp2_frame_settings_init(&frame->settings, iv_copy, niv);
-
-  r = nghttp2_session_update_local_settings(session, iv_copy, niv);
-  if(r != 0) {
-    nghttp2_frame_settings_free(&frame->settings);
-    free(frame);
-    return r;
-  }
-  r = nghttp2_session_add_frame(session, NGHTTP2_CAT_CTRL, frame, NULL);
-  if(r != 0) {
-    /* The only expected error is fatal one */
-    assert(r < NGHTTP2_ERR_FATAL);
-    nghttp2_frame_settings_free(&frame->settings);
-    free(frame);
-  }
-  return r;
+  return nghttp2_session_add_settings(session, NGHTTP2_FLAG_NONE, iv, niv);
 }
 
 int nghttp2_submit_push_promise(nghttp2_session *session, uint8_t flags,

src/app_helper.cc

@@ -80,12 +80,16 @@ namespace {
 const char* strsettingsid(int32_t id)
 {
   switch(id) {
+  case NGHTTP2_SETTINGS_HEADER_TABLE_SIZE:
+    return "SETTINGS_HEADER_TABLE_SIZE";
+  case NGHTTP2_SETTINGS_ENABLE_PUSH:
+    return "SETTINGS_ENABLE_PUSH";
   case NGHTTP2_SETTINGS_MAX_CONCURRENT_STREAMS:
-    return "MAX_CONCURRENT_STREAMS";
+    return "SETTINGS_MAX_CONCURRENT_STREAMS";
   case NGHTTP2_SETTINGS_INITIAL_WINDOW_SIZE:
-    return "INITIAL_WINDOW_SIZE";
+    return "SETTINGS_INITIAL_WINDOW_SIZE";
   case NGHTTP2_SETTINGS_FLOW_CONTROL_OPTIONS:
-    return "FLOW_CONTROL_OPTIONS";
+    return "SETTINGS_FLOW_CONTROL_OPTIONS";
   default:
     return "UNKNOWN";
   }
@@ -208,14 +212,19 @@ void print_flags(const nghttp2_frame_hd& hd)
       s += "PRIORITY";
     }
     break;
+  case NGHTTP2_SETTINGS:
+    if(hd.flags & NGHTTP2_FLAG_ACK) {
+      s += "ACK";
+    }
+    break;
   case NGHTTP2_PUSH_PROMISE:
     if(hd.flags & NGHTTP2_FLAG_END_PUSH_PROMISE) {
       s += "END_PUSH_PROMISE";
     }
     break;
   case NGHTTP2_PING:
-    if(hd.flags & NGHTTP2_FLAG_PONG) {
-      s += "PONG";
+    if(hd.flags & NGHTTP2_FLAG_ACK) {
+      s += "ACK";
     }
     break;
   }

tests/nghttp2_frame_test.c

@@ -223,7 +223,8 @@ void test_nghttp2_frame_pack_settings()
   iv[2].settings_id = NGHTTP2_SETTINGS_FLOW_CONTROL_OPTIONS;
   iv[2].value = 1;
 
-  nghttp2_frame_settings_init(&frame, nghttp2_frame_iv_copy(iv, 3), 3);
+  nghttp2_frame_settings_init(&frame, NGHTTP2_FLAG_NONE,
+                              nghttp2_frame_iv_copy(iv, 3), 3);
   framelen = nghttp2_frame_pack_settings(&buf, &buflen, &frame);
   CU_ASSERT(NGHTTP2_FRAME_HEAD_LENGTH+3*8 == framelen);
 
@@ -290,14 +291,14 @@ void test_nghttp2_frame_pack_ping(void)
   size_t buflen = 0;
   ssize_t framelen;
   const uint8_t opaque_data[] = "01234567";
-  nghttp2_frame_ping_init(&frame, NGHTTP2_FLAG_PONG, opaque_data);
+  nghttp2_frame_ping_init(&frame, NGHTTP2_FLAG_ACK, opaque_data);
   framelen = nghttp2_frame_pack_ping(&buf, &buflen, &frame);
   CU_ASSERT(0 == nghttp2_frame_unpack_ping
             (&oframe,
              &buf[0], NGHTTP2_FRAME_HEAD_LENGTH,
              &buf[NGHTTP2_FRAME_HEAD_LENGTH],
              framelen - NGHTTP2_FRAME_HEAD_LENGTH));
-  check_frame_header(8, NGHTTP2_PING, NGHTTP2_FLAG_PONG, 0, &oframe.hd);
+  check_frame_header(8, NGHTTP2_PING, NGHTTP2_FLAG_ACK, 0, &oframe.hd);
   CU_ASSERT(memcmp(opaque_data, oframe.opaque_data, sizeof(opaque_data) - 1)
             == 0);
   free(buf);