diff --git a/src/core/ngx_rbtree.h b/src/core/ngx_rbtree.h
index 97f0e3e..e8c3582 100644
--- a/src/core/ngx_rbtree.h
+++ b/src/core/ngx_rbtree.h
@@ -47,6 +47,9 @@
     (tree)->sentinel = s;                                                     \
     (tree)->insert = i
 
+#define ngx_rbtree_data(node, type, link)                                     \
+    (type *) ((u_char *) (node) - offsetof(type, link))
+
 
 void ngx_rbtree_insert(ngx_rbtree_t *tree, ngx_rbtree_node_t *node);
 void ngx_rbtree_delete(ngx_rbtree_t *tree, ngx_rbtree_node_t *node);
diff --git a/src/core/ngx_resolver.c b/src/core/ngx_resolver.c
index 58d5f3e..6d129e5 100644
--- a/src/core/ngx_resolver.c
+++ b/src/core/ngx_resolver.c
@@ -51,9 +51,7 @@
 } ngx_resolver_an_t;
 
 
-#define ngx_resolver_node(n)                                                 \
-    (ngx_resolver_node_t *)                                                  \
-        ((u_char *) (n) - offsetof(ngx_resolver_node_t, node))
+#define ngx_resolver_node(n)  ngx_rbtree_data(n, ngx_resolver_node_t, node)
 
 
 static ngx_int_t ngx_udp_connect(ngx_resolver_connection_t *rec);
diff --git a/src/event/ngx_event_timer.c b/src/event/ngx_event_timer.c
index 698b88f..35052bc 100644
--- a/src/event/ngx_event_timer.c
+++ b/src/event/ngx_event_timer.c
@@ -73,7 +73,7 @@
             return;
         }
 
-        ev = (ngx_event_t *) ((char *) node - offsetof(ngx_event_t, timer));
+        ev = ngx_rbtree_data(node, ngx_event_t, timer);
 
         ngx_log_debug2(NGX_LOG_DEBUG_EVENT, ev->log, 0,
                        "event timer del: %d: %M",
@@ -113,7 +113,7 @@
          node;
          node = ngx_rbtree_next(&ngx_event_timer_rbtree, node))
     {
-        ev = (ngx_event_t *) ((char *) node - offsetof(ngx_event_t, timer));
+        ev = ngx_rbtree_data(node, ngx_event_t, timer);
 
         if (!ev->cancelable) {
             return NGX_AGAIN;