Add nghttp2_option_set_user_recv_extension_type to opt-in incoming extension type

lib/includes/nghttp2/nghttp2.h

@@ -2186,6 +2186,21 @@ NGHTTP2_EXTERN void
 nghttp2_option_set_max_reserved_remote_streams(nghttp2_option *option,
                                                uint32_t val);
 
+/**
+ * @function
+ *
+ * Set extension frame type the application is willing to handle with
+ * user defined callbacks (see
+ * :type:`nghttp2_on_extension_chunk_recv_callback` and
+ * :type:`nghttp2_unpack_extension_callback`).  The |type| is
+ * extension frame type, and must be strictly greater than 0x9.
+ * Otherwise, this function does nothing.  The application does not
+ * have to call this function if it just sends extension frames.
+ */
+NGHTTP2_EXTERN void
+nghttp2_option_set_user_recv_extension_type(nghttp2_option *option,
+                                            uint8_t type);
+
 /**
  * @function
  *

lib/nghttp2_option.c

@@ -62,3 +62,13 @@ void nghttp2_option_set_max_reserved_remote_streams(nghttp2_option *option,
   option->opt_set_mask |= NGHTTP2_OPT_MAX_RESERVED_REMOTE_STREAMS;
   option->max_reserved_remote_streams = val;
 }
+
+void nghttp2_option_set_user_recv_extension_type(nghttp2_option *option,
+                                                 uint8_t type) {
+  if (type < 10) {
+    return;
+  }
+
+  option->opt_set_mask |= NGHTTP2_OPT_USER_RECV_EXT_TYPES;
+  option->user_recv_ext_types[type / 8] |= 1 << (7 - (type & 0x7));
+}

lib/nghttp2_option.h

@@ -59,7 +59,8 @@ typedef enum {
   NGHTTP2_OPT_PEER_MAX_CONCURRENT_STREAMS = 1 << 1,
   NGHTTP2_OPT_NO_RECV_CLIENT_MAGIC = 1 << 2,
   NGHTTP2_OPT_NO_HTTP_MESSAGING = 1 << 3,
-  NGHTTP2_OPT_MAX_RESERVED_REMOTE_STREAMS = 1 << 4
+  NGHTTP2_OPT_MAX_RESERVED_REMOTE_STREAMS = 1 << 4,
+  NGHTTP2_OPT_USER_RECV_EXT_TYPES = 1 << 5
 } nghttp2_option_flag;
 
 /**
@@ -91,6 +92,10 @@ struct nghttp2_option {
    * NGHTTP2_OPT_NO_HTTP_MESSAGING
    */
   int no_http_messaging;
+  /**
+   * NGHTTP2_OPT_USER_RECV_EXT_TYPES
+   */
+  uint8_t user_recv_ext_types[32];
 };
 
 #endif /* NGHTTP2_OPTION_H */

lib/nghttp2_session.c

@@ -402,6 +402,11 @@ static int session_new(nghttp2_session **session_ptr,
 
       (*session_ptr)->opt_flags |= NGHTTP2_OPTMASK_NO_HTTP_MESSAGING;
     }
+
+    if (option->opt_set_mask & NGHTTP2_OPT_USER_RECV_EXT_TYPES) {
+      memcpy((*session_ptr)->user_recv_ext_types, option->user_recv_ext_types,
+             sizeof((*session_ptr)->user_recv_ext_types));
+    }
   }
 
   (*session_ptr)->callbacks = *callbacks;
@@ -5291,7 +5296,9 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
       default:
         DEBUGF(fprintf(stderr, "recv: unknown frame\n"));
 
-        if (!session->callbacks.unpack_extension_callback) {
+        if (!session->callbacks.unpack_extension_callback ||
+            (session->user_recv_ext_types[iframe->frame.hd.type / 8] &
+             (1 << (7 - (iframe->frame.hd.type & 0x7)))) == 0) {
           /* Silently ignore unknown frame type. */
 
           busy = 1;

lib/nghttp2_session.h

@@ -296,6 +296,12 @@ struct nghttp2_session {
      this session.  The nonzero does not necessarily mean
      WINDOW_UPDATE is not queued. */
   uint8_t window_update_queued;
+  /* Bitfield of extension frame types that application is willing to
+     receive.  First most significant 10 bits are standard frame types
+     and not used.  If bit is set, it indicates that incoming frame
+     with that type is passed to user defined callbacks, otherwise
+     they are ignored. */
+  uint8_t user_recv_ext_types[32];
 };
 
 /* Struct used when updating initial window size of each active

tests/nghttp2_session_test.c

@@ -1769,6 +1769,7 @@ void test_nghttp2_session_recv_extension(void) {
   nghttp2_mem *mem;
   const char data[] = "Hello World!";
   ssize_t rv;
+  nghttp2_option *option;
 
   mem = nghttp2_mem_default();
 
@@ -1778,6 +1779,9 @@ void test_nghttp2_session_recv_extension(void) {
   callbacks.unpack_extension_callback = unpack_extension_callback;
   callbacks.on_frame_recv_callback = on_frame_recv_callback;
 
+  nghttp2_option_new(&option);
+  nghttp2_option_set_user_recv_extension_type(option, 111);
+
   nghttp2_buf_init2(&ud.scratchbuf, 4096, mem);
   nghttp2_buf_init2(&buf, 4096, mem);
 
@@ -1786,7 +1790,7 @@ void test_nghttp2_session_recv_extension(void) {
   buf.last += NGHTTP2_FRAME_HDLEN;
   buf.last = nghttp2_cpymem(buf.last, data, sizeof(data));
 
-  nghttp2_session_client_new(&session, &callbacks, &ud);
+  nghttp2_session_client_new2(&session, &callbacks, &ud, option);
 
   nghttp2_frame_hd_init(&ud.recv_frame_hd, 0, 0, 0, 0);
   rv = nghttp2_session_mem_recv(session, buf.pos, nghttp2_buf_len(&buf));
@@ -1805,7 +1809,7 @@ void test_nghttp2_session_recv_extension(void) {
   callbacks.on_extension_chunk_recv_callback =
       cancel_on_extension_chunk_recv_callback;
 
-  nghttp2_session_server_new(&session, &callbacks, &ud);
+  nghttp2_session_server_new2(&session, &callbacks, &ud, option);
 
   ud.frame_recv_cb_called = 0;
   rv = nghttp2_session_mem_recv(session, buf.pos, nghttp2_buf_len(&buf));
@@ -1821,7 +1825,7 @@ void test_nghttp2_session_recv_extension(void) {
   callbacks.on_extension_chunk_recv_callback = on_extension_chunk_recv_callback;
   callbacks.unpack_extension_callback = cancel_unpack_extension_callback;
 
-  nghttp2_session_server_new(&session, &callbacks, &ud);
+  nghttp2_session_server_new2(&session, &callbacks, &ud, option);
 
   ud.frame_recv_cb_called = 0;
   rv = nghttp2_session_mem_recv(session, buf.pos, nghttp2_buf_len(&buf));
@@ -1833,6 +1837,8 @@ void test_nghttp2_session_recv_extension(void) {
 
   nghttp2_buf_free(&buf, mem);
   nghttp2_buf_free(&ud.scratchbuf, mem);
+
+  nghttp2_option_del(option);
 }
 
 void test_nghttp2_session_continue(void) {