vppinfra: make _vec_len() read-only

Use of _vec_len() to set vector length breaks address sanitizer.
Users should use vec_set_len(), vec_inc_len(), vec_dec_len () instead.

Type: improvement
Change-Id: I441ae948771eb21c23a61f3ff9163bdad74a2cb8
Signed-off-by: Damjan Marion <damarion@cisco.com>
diff --git a/src/vnet/classify/vnet_classify.c b/src/vnet/classify/vnet_classify.c
index 1bdbee7..c9a6fc6 100644
--- a/src/vnet/classify/vnet_classify.c
+++ b/src/vnet/classify/vnet_classify.c
@@ -1320,7 +1320,7 @@
       if (match == 0)
 	clib_warning ("BUG: match 0");
 
-      _vec_len (mask) = match * sizeof (u32x4);
+      vec_set_len (mask, match * sizeof (u32x4));
 
       *matchp = match;
       *maskp = mask;
@@ -2770,8 +2770,8 @@
 	 sizeof (u32x4));
 
       /* Set size, include skipped vectors */
-      _vec_len (match) =
-	(t->match_n_vectors + t->skip_n_vectors) * sizeof (u32x4);
+      vec_set_len (match,
+		   (t->match_n_vectors + t->skip_n_vectors) * sizeof (u32x4));
 
       *matchp = match;