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>

26 files changed, 84 insertions, 81 deletions

diff --git a/src/vppinfra/bitmap.h b/src/vppinfra/bitmap.h
index 096d3f1aa4a..02f9c7e55ab 100644
--- a/src/vppinfra/bitmap.h
+++ b/src/vppinfra/bitmap.h
@@ -142,7 +142,7 @@ _clib_bitmap_remove_trailing_zeros (uword * a)
       for (i = _vec_len (a) - 1; i >= 0; i--)
 	if (a[i] != 0)
 	  break;
-      _vec_len (a) = i + 1;
+      vec_set_len (a, i + 1);
     }
   return a;
 }
@@ -518,29 +518,32 @@ always_inline uword *clib_bitmap_or (uword * ai, uword * bi);
 always_inline uword *clib_bitmap_xor (uword * ai, uword * bi);
 
 /* ALU function definition macro for functions taking two bitmaps. */
-#define _(name, body, check_zero)				\
-always_inline uword *						\
-clib_bitmap_##name (uword * ai, uword * bi)			\
-{								\
-  uword i, a, b, bi_len, n_trailing_zeros;			\
-								\
-  n_trailing_zeros = 0;						\
-  bi_len = vec_len (bi);					\
-  if (bi_len > 0)						\
-    clib_bitmap_vec_validate (ai, bi_len - 1);			\
-  for (i = 0; i < vec_len (ai); i++)				\
-    {								\
-      a = ai[i];						\
-      b = i < bi_len ? bi[i] : 0;				\
-      do { body; } while (0);					\
-      ai[i] = a;						\
-      if (check_zero)						\
-	n_trailing_zeros = a ? 0 : (n_trailing_zeros + 1);	\
-    }								\
-  if (check_zero)						\
-    _vec_len (ai) -= n_trailing_zeros;				\
-  return ai;							\
-}
+#define _(name, body, check_zero)                                             \
+  always_inline uword *clib_bitmap_##name (uword *ai, uword *bi)              \
+  {                                                                           \
+    uword i, a, b, bi_len, n_trailing_zeros;                                  \
+                                                                              \
+    n_trailing_zeros = 0;                                                     \
+    bi_len = vec_len (bi);                                                    \
+    if (bi_len > 0)                                                           \
+      clib_bitmap_vec_validate (ai, bi_len - 1);                              \
+    for (i = 0; i < vec_len (ai); i++)                                        \
+      {                                                                       \
+	a = ai[i];                                                            \
+	b = i < bi_len ? bi[i] : 0;                                           \
+	do                                                                    \
+	  {                                                                   \
+	    body;                                                             \
+	  }                                                                   \
+	while (0);                                                            \
+	ai[i] = a;                                                            \
+	if (check_zero)                                                       \
+	  n_trailing_zeros = a ? 0 : (n_trailing_zeros + 1);                  \
+      }                                                                       \
+    if (check_zero)                                                           \
+      vec_dec_len (ai, n_trailing_zeros);                                     \
+    return ai;                                                                \
+  }
 
 /* ALU functions: */
 /* *INDENT-OFF* */
diff --git a/src/vppinfra/elf.c b/src/vppinfra/elf.c
index 7a74fad4c4f..d11fd7e99a9 100644
--- a/src/vppinfra/elf.c
+++ b/src/vppinfra/elf.c
@@ -1975,7 +1975,7 @@ elf_create_section_with_contents (elf_main_t * em,
   if ((p = hash_get_mem (em->section_by_name, section_name)))
     {
       s = vec_elt_at_index (em->sections, p[0]);
-      _vec_len (s->contents) = 0;
+      vec_set_len (s->contents, 0);
       c = s->contents;
     }
   else
diff --git a/src/vppinfra/elog.c b/src/vppinfra/elog.c
index 8ae752eb6af..ddc09a37d72 100644
--- a/src/vppinfra/elog.c
+++ b/src/vppinfra/elog.c
@@ -494,7 +494,7 @@ elog_alloc_internal (elog_main_t * em, u32 n_events, int free_ring)
   em->event_ring_size = n_events = max_pow2 (n_events);
 
   vec_validate_aligned (em->event_ring, n_events, CLIB_CACHE_LINE_BYTES);
-  _vec_len (em->event_ring) = n_events;
+  vec_set_len (em->event_ring, n_events);
 }
 
 __clib_export void
diff --git a/src/vppinfra/fifo.h b/src/vppinfra/fifo.h
index 611fadb95d7..b6a8b8f5c3b 100644
--- a/src/vppinfra/fifo.h
+++ b/src/vppinfra/fifo.h
@@ -91,7 +91,7 @@ clib_fifo_reset (void *v)
   if (v)
     {
       f->head_index = f->tail_index = 0;
-      _vec_len (v) = 0;
+      vec_set_len (v, 0);
     }
 }
 
diff --git a/src/vppinfra/format.c b/src/vppinfra/format.c
index ccd999e582f..cf17b8a1acb 100644
--- a/src/vppinfra/format.c
+++ b/src/vppinfra/format.c
@@ -114,7 +114,7 @@ justify (u8 * s, format_info_t * fi, uword s_len_orig)
     l0 = l1;
 
   if (l1 > l0)
-    _vec_len (s) = l0;
+    vec_set_len (s, l0);
   else if (l0 > l1)
     {
       uword n = l0 - l1;
diff --git a/src/vppinfra/hash.c b/src/vppinfra/hash.c
index df740c5f659..7deff4a5bee 100644
--- a/src/vppinfra/hash.c
+++ b/src/vppinfra/hash.c
@@ -342,7 +342,7 @@ unset_indirect (void *v, uword i, hash_pair_t * q)
       else
 	zero_pair (h, q);
       if (is_vec)
-	_vec_len (pi->pairs) -= 1;
+	vec_dec_len (pi->pairs, 1);
       else
 	indirect_pair_set (pi, indirect_pair_get_log2_bytes (pi), len - 1);
     }
diff --git a/src/vppinfra/heap.c b/src/vppinfra/heap.c
index 47b6cf53214..066756b4db9 100644
--- a/src/vppinfra/heap.c
+++ b/src/vppinfra/heap.c
@@ -139,7 +139,7 @@ elt_delete (heap_header_t * h, heap_elt_t * e)
   if (e < l)
     vec_add1 (h->free_elts, e - h->elts);
   else
-    _vec_len (h->elts)--;
+    vec_dec_len (h->elts, 1);
 }
 
 /*
@@ -200,7 +200,7 @@ elt_new (heap_header_t * h)
   if ((l = vec_len (h->free_elts)) > 0)
     {
       e = elt_at (h, h->free_elts[l - 1]);
-      _vec_len (h->free_elts) -= 1;
+      vec_dec_len (h->free_elts, 1);
     }
   else
     vec_add2 (h->elts, e, 1);
@@ -276,7 +276,7 @@ remove_free_block (void *v, uword b, uword i)
       h->free_lists[b][i] = t;
       set_free_elt (v, elt_at (h, t), i);
     }
-  _vec_len (h->free_lists[b]) = l - 1;
+  vec_set_len (h->free_lists[b], l - 1);
 }
 
 static heap_elt_t *
@@ -425,7 +425,7 @@ _heap_alloc (void *v,
 	v = _vec_realloc (v, offset + align_size, elt_bytes, sizeof (h[0]),
 			  HEAP_DATA_ALIGN, 0);
       else
-	_vec_len (v) += align_size;
+	vec_inc_len (v, align_size);
 
       if (offset == 0)
 	{
diff --git a/src/vppinfra/linux/mem.c b/src/vppinfra/linux/mem.c
index 6c3e036d951..9cf598d3c6f 100644
--- a/src/vppinfra/linux/mem.c
+++ b/src/vppinfra/linux/mem.c
@@ -261,7 +261,7 @@ clib_mem_vm_create_fd (clib_mem_page_sz_t log2_page_size, char *fmt, ...)
 
   /* memfd_create maximum string size is 249 chars without trailing zero */
   if (vec_len (s) > 249)
-    _vec_len (s) = 249;
+    vec_set_len (s, 249);
   vec_add1 (s, 0);
 
   /* memfd_create introduced in kernel 3.17, we don't support older kernels */
diff --git a/src/vppinfra/linux/sysfs.c b/src/vppinfra/linux/sysfs.c
index 758eaa1a86c..a3e122cf1e0 100644
--- a/src/vppinfra/linux/sysfs.c
+++ b/src/vppinfra/linux/sysfs.c
@@ -70,7 +70,7 @@ clib_sysfs_read (char *file_name, char *fmt, ...)
       return clib_error_return_unix (0, "read `%s'", file_name);
     }
 
-  _vec_len (s) = sz;
+  vec_set_len (s, sz);
   unformat_init_vector (&input, s);
 
   va_list va;
@@ -154,7 +154,7 @@ clib_sysfs_set_nr_hugepages (int numa_node, int log2_page_size, int nr)
       goto done;
     }
 
-  _vec_len (p) -= 1;
+  vec_dec_len (p, 1);
   p = format (p, "/hugepages/hugepages-%ukB/nr_hugepages%c", page_size, 0);
   clib_sysfs_write ((char *) p, "%d", nr);
 
@@ -207,7 +207,7 @@ clib_sysfs_get_xxx_hugepages (char *type, int numa_node,
       goto done;
     }
 
-  _vec_len (p) -= 1;
+  vec_dec_len (p, 1);
   p = format (p, "/hugepages/hugepages-%ukB/%s_hugepages%c", page_size,
 	      type, 0);
   error = clib_sysfs_read ((char *) p, "%d", val);
diff --git a/src/vppinfra/macros.c b/src/vppinfra/macros.c
index b8a8e1744aa..27a92a8abe2 100644
--- a/src/vppinfra/macros.c
+++ b/src/vppinfra/macros.c
@@ -175,7 +175,7 @@ clib_macro_eval (clib_macro_main_t * mm, i8 * s, i32 complain, u16 level,
 	      /* add results to answer */
 	      vec_append (rv, ts);
 	      /* Remove NULL termination or the results are sad */
-	      _vec_len (rv) = vec_len (rv) - 1;
+	      vec_set_len (rv, vec_len (rv) - 1);
 	      vec_free (ts);
 	    }
 	  else
@@ -183,8 +183,7 @@ clib_macro_eval (clib_macro_main_t * mm, i8 * s, i32 complain, u16 level,
 	      if (complain)
 		clib_warning ("Undefined Variable Reference: %s\n", varname);
 	      vec_append (rv, format (0, "UNSET "));
-	      _vec_len (rv) = vec_len (rv) - 1;
-
+	      vec_set_len (rv, vec_len (rv) - 1);
 	    }
 	  vec_free (varname);
 	}
diff --git a/src/vppinfra/mem_dlmalloc.c b/src/vppinfra/mem_dlmalloc.c
index 3829e7c7740..fdde720bc73 100644
--- a/src/vppinfra/mem_dlmalloc.c
+++ b/src/vppinfra/mem_dlmalloc.c
@@ -101,7 +101,7 @@ mheap_get_trace (uword offset, uword size)
       if (i > 0)
 	{
 	  trace_index = tm->trace_free_list[i - 1];
-	  _vec_len (tm->trace_free_list) = i - 1;
+	  vec_set_len (tm->trace_free_list, i - 1);
 	}
       else
 	{
diff --git a/src/vppinfra/mhash.c b/src/vppinfra/mhash.c
index c556312e64f..f0f1aa470d7 100644
--- a/src/vppinfra/mhash.c
+++ b/src/vppinfra/mhash.c
@@ -295,7 +295,7 @@ mhash_set_mem (mhash_t * h, void *key, uword * new_value, uword * old_value)
 	{
 	  i = h->key_vector_free_indices[l - 1];
 	  k = vec_elt_at_index (h->key_vector_or_heap, i);
-	  _vec_len (h->key_vector_free_indices) = l - 1;
+	  vec_set_len (h->key_vector_free_indices, l - 1);
 	}
       else
 	{
@@ -332,10 +332,10 @@ mhash_set_mem (mhash_t * h, void *key, uword * new_value, uword * old_value)
 	  if (key_alloc_from_free_list)
 	    {
 	      h->key_vector_free_indices[l] = i;
-	      _vec_len (h->key_vector_free_indices) = l + 1;
+	      vec_set_len (h->key_vector_free_indices, l + 1);
 	    }
 	  else
-	    _vec_len (h->key_vector_or_heap) -= h->n_key_bytes;
+	    vec_dec_len (h->key_vector_or_heap, h->n_key_bytes);
 	}
     }
 
diff --git a/src/vppinfra/pool.h b/src/vppinfra/pool.h
index 4db1f7b6bdf..9f9194f59e2 100644
--- a/src/vppinfra/pool.h
+++ b/src/vppinfra/pool.h
@@ -184,7 +184,7 @@ _pool_get (void **pp, void **ep, uword align, int zero, uword elt_sz)
 	  e = p + index * elt_sz;
 	  ph->free_bitmap =
 	    clib_bitmap_andnoti_notrim (ph->free_bitmap, index);
-	  _vec_len (ph->free_indices) = n_free - 1;
+	  vec_set_len (ph->free_indices, n_free - 1);
 	  CLIB_MEM_UNPOISON (e, elt_sz);
 	  goto done;
 	}
@@ -294,7 +294,7 @@ _pool_put_index (void *p, uword index, uword elt_sz)
   if (ph->max_elts)
     {
       ph->free_indices[_vec_len (ph->free_indices)] = index;
-      _vec_len (ph->free_indices) += 1;
+      vec_inc_len (ph->free_indices, 1);
     }
   else
     vec_add1 (ph->free_indices, index);
@@ -321,12 +321,12 @@ _pool_alloc (void **pp, uword n_elts, uword align, void *heap, uword elt_sz)
 
   pp[0] = _vec_realloc_inline (pp[0], len + n_elts, elt_sz,
 			       sizeof (pool_header_t), align, heap);
-  _vec_len (pp[0]) = len;
+  _vec_set_len (pp[0], len, elt_sz);
   CLIB_MEM_POISON (pp[0] + len * elt_sz, n_elts * elt_sz);
 
   ph = pool_header (pp[0]);
   vec_resize (ph->free_indices, n_elts);
-  _vec_len (ph->free_indices) -= n_elts;
+  vec_dec_len (ph->free_indices, n_elts);
   clib_bitmap_vec_validate (ph->free_bitmap, len + n_elts - 1);
 }
 
diff --git a/src/vppinfra/random_buffer.h b/src/vppinfra/random_buffer.h
index dded53163fc..078e9607caa 100644
--- a/src/vppinfra/random_buffer.h
+++ b/src/vppinfra/random_buffer.h
@@ -100,7 +100,7 @@ clib_random_buffer_get_data (clib_random_buffer_t * b, uword n_bytes)
     clib_random_buffer_fill (b, n_words);
 
   i = vec_len (b->buffer) - n_words;
-  _vec_len (b->buffer) = i;
+  vec_set_len (b->buffer, i);
 
   if (n_bytes < sizeof (uword))
     {
diff --git a/src/vppinfra/serialize.c b/src/vppinfra/serialize.c
index 95eca96758a..d84d7ca06c5 100644
--- a/src/vppinfra/serialize.c
+++ b/src/vppinfra/serialize.c
@@ -714,7 +714,7 @@ serialize_write_not_inline (serialize_main_header_t * m,
 	  n_left_b -= n;
 	  n_left_o -= n;
 	  if (n_left_o == 0)
-	    _vec_len (s->overflow_buffer) = 0;
+	    vec_set_len (s->overflow_buffer, 0);
 	  else
 	    vec_delete (s->overflow_buffer, n, 0);
 	}
@@ -771,7 +771,7 @@ serialize_read_not_inline (serialize_main_header_t * m,
   if (n_left_o == 0 && s->overflow_buffer)
     {
       s->current_overflow_index = 0;
-      _vec_len (s->overflow_buffer) = 0;
+      vec_set_len (s->overflow_buffer, 0);
     }
 
   n_left_to_read = n_bytes_to_read;
@@ -923,7 +923,7 @@ serialize_close_vector (serialize_main_t * m)
   serialize_close (m);		/* frees overflow buffer */
 
   if (s->buffer)
-    _vec_len (s->buffer) = s->current_buffer_index;
+    vec_set_len (s->buffer, s->current_buffer_index);
   result = s->buffer;
   clib_memset (m, 0, sizeof (m[0]));
   return result;
@@ -1161,7 +1161,7 @@ clib_file_write (serialize_main_header_t * m, serialize_stream_t * s)
 	serialize_error (m, clib_error_return_unix (0, "write"));
     }
   if (n == s->current_buffer_index)
-    _vec_len (s->buffer) = 0;
+    vec_set_len (s->buffer, 0);
   else
     vec_delete (s->buffer, n, 0);
   s->current_buffer_index = vec_len (s->buffer);
@@ -1197,7 +1197,7 @@ serialize_open_clib_file_descriptor_helper (serialize_main_t * m, int fd,
   if (!is_read)
     {
       m->stream.n_buffer_bytes = vec_len (m->stream.buffer);
-      _vec_len (m->stream.buffer) = 0;
+      vec_set_len (m->stream.buffer, 0);
     }
 
   m->header.data_function = is_read ? clib_file_read : clib_file_write;
diff --git a/src/vppinfra/socket.c b/src/vppinfra/socket.c
index a09a390dab3..a3024ae7a8c 100644
--- a/src/vppinfra/socket.c
+++ b/src/vppinfra/socket.c
@@ -230,7 +230,7 @@ default_socket_write (clib_socket_t * s)
   else if (written > 0)
     {
       if (written == tx_len)
-	_vec_len (s->tx_buffer) = 0;
+	vec_set_len (s->tx_buffer, 0);
       else
 	vec_delete (s->tx_buffer, written, 0);
     }
@@ -278,7 +278,7 @@ default_socket_read (clib_socket_t * sock, int n_bytes)
     sock->flags |= CLIB_SOCKET_F_RX_END_OF_FILE;
 
 non_fatal:
-  _vec_len (sock->rx_buffer) += n_read - n_bytes;
+  vec_inc_len (sock->rx_buffer, n_read - n_bytes);
 
   return 0;
 }
diff --git a/src/vppinfra/sparse_vec.h b/src/vppinfra/sparse_vec.h
index 6cab868a8b2..dc9cb00380a 100644
--- a/src/vppinfra/sparse_vec.h
+++ b/src/vppinfra/sparse_vec.h
@@ -81,7 +81,7 @@ sparse_vec_new (uword elt_bytes, uword sparse_index_bits)
 		    /* heap */ 0);
 
   /* Make space for invalid entry (entry 0). */
-  _vec_len (v) = 1;
+  _vec_find (v)->len = 1;
 
   h = sparse_vec_header (v);
 
diff --git a/src/vppinfra/test_bihash_template.c b/src/vppinfra/test_bihash_template.c
index ffed5c73287..155b8bd408d 100644
--- a/src/vppinfra/test_bihash_template.c
+++ b/src/vppinfra/test_bihash_template.c
@@ -522,8 +522,7 @@ test_bihash_main (test_main_t * tm)
   /* Preallocate hash table, key vector */
   tm->key_hash = hash_create (tm->nitems, sizeof (uword));
   vec_validate (tm->keys, tm->nitems - 1);
-  _vec_len (tm->keys) = 0;
-
+  vec_set_len (tm->keys, 0);
 
   switch (which)
     {
diff --git a/src/vppinfra/test_fpool.c b/src/vppinfra/test_fpool.c
index e2d67f16907..02d9d219717 100644
--- a/src/vppinfra/test_fpool.c
+++ b/src/vppinfra/test_fpool.c
@@ -30,7 +30,7 @@ main (int argc, char *argv[])
   clib_mem_init (0, 3ULL << 30);
 
   vec_validate (indices, NELTS - 1);
-  _vec_len (indices) = 0;
+  vec_set_len (indices, 0);
 
   pool_init_fixed (tp, NELTS);
 
diff --git a/src/vppinfra/test_socket.c b/src/vppinfra/test_socket.c
index ea0ae658943..3a0e6b29ce6 100644
--- a/src/vppinfra/test_socket.c
+++ b/src/vppinfra/test_socket.c
@@ -99,7 +99,7 @@ test_socket_main (unformat_input_t * input)
 	break;
 
       if_verbose ("%v", s->rx_buffer);
-      _vec_len (s->rx_buffer) = 0;
+      vec_set_len (s->rx_buffer, 0);
     }
 
   error = clib_socket_close (s);
diff --git a/src/vppinfra/timing_wheel.c b/src/vppinfra/timing_wheel.c
index 2c46d72a2fe..edd878239cf 100644
--- a/src/vppinfra/timing_wheel.c
+++ b/src/vppinfra/timing_wheel.c
@@ -185,7 +185,7 @@ free_elt_vector (timing_wheel_t * w, timing_wheel_elt_t * ev)
   /* Poison free elements so we never use them by mistake. */
   if (CLIB_DEBUG > 0)
     clib_memset (ev, ~0, vec_len (ev) * sizeof (ev[0]));
-  _vec_len (ev) = 0;
+  vec_set_len (ev, 0);
   vec_add1 (w->free_elt_vectors, ev);
 }
 
@@ -459,7 +459,7 @@ expire_bin (timing_wheel_t * w,
 
   /* Adjust for deleted elts. */
   if (j < e_len)
-    _vec_len (expired_user_data) -= e_len - j;
+    vec_dec_len (expired_user_data, e_len - j);
 
   free_elt_vector (w, e);
 
@@ -613,7 +613,7 @@ timing_wheel_advance (timing_wheel_t * w, u64 advance_cpu_time,
     if (PREDICT_FALSE (current_ti != advance_ti))
       {
 	if (w->unexpired_elts_pending_insert)
-	  _vec_len (w->unexpired_elts_pending_insert) = 0;
+	  vec_set_len (w->unexpired_elts_pending_insert, 0);
 
 	level_index = 0;
 	while (current_ti != advance_ti)
@@ -684,7 +684,7 @@ timing_wheel_advance (timing_wheel_t * w, u64 advance_cpu_time,
     {
       timing_wheel_elt_t *e;
       vec_foreach (e, w->unexpired_elts_pending_insert) insert_elt (w, e);
-      _vec_len (w->unexpired_elts_pending_insert) = 0;
+      vec_set_len (w->unexpired_elts_pending_insert, 0);
     }
 
   /* Don't advance until necessary. */
diff --git a/src/vppinfra/tw_timer_template.c b/src/vppinfra/tw_timer_template.c
index 97c70b223ce..6e8a58dbfaf 100644
--- a/src/vppinfra/tw_timer_template.c
+++ b/src/vppinfra/tw_timer_template.c
@@ -424,7 +424,7 @@ TW (tw_timer_wheel_init) (TWT (tw_timer_wheel) * tw,
   tw->ticks_per_second = 1.0 / timer_interval_in_seconds;
 
   vec_validate (tw->expired_timer_handles, 0);
-  _vec_len (tw->expired_timer_handles) = 0;
+  vec_set_len (tw->expired_timer_handles, 0);
 
   for (ring = 0; ring < TW_TIMER_WHEELS; ring++)
     {
@@ -536,7 +536,7 @@ static inline
 
   if (callback_vector_arg == 0)
     {
-      _vec_len (tw->expired_timer_handles) = 0;
+      vec_set_len (tw->expired_timer_handles, 0);
       callback_vector = tw->expired_timer_handles;
     }
   else
diff --git a/src/vppinfra/unformat.c b/src/vppinfra/unformat.c
index 3904b450f48..e8e5c28ea8c 100644
--- a/src/vppinfra/unformat.c
+++ b/src/vppinfra/unformat.c
@@ -952,7 +952,7 @@ parse_fail:
     if (!input_matches_format)
       input->index = input->buffer_marks[l - 1];
 
-    _vec_len (input->buffer_marks) = l - 1;
+    vec_set_len (input->buffer_marks, l - 1);
   }
 
   return input_matches_format;
@@ -987,7 +987,7 @@ unformat_user (unformat_input_t * input, unformat_function_t * func, ...)
   if (!result && input->index != UNFORMAT_END_OF_INPUT)
     input->index = input->buffer_marks[l];
 
-  _vec_len (input->buffer_marks) = l;
+  vec_set_len (input->buffer_marks, l);
 
   return result;
 }
@@ -1037,7 +1037,7 @@ clib_file_fill_buffer (unformat_input_t * input)
   vec_resize (input->buffer, 4096);
   n = read (fd, input->buffer + l, 4096);
   if (n > 0)
-    _vec_len (input->buffer) = l + n;
+    vec_set_len (input->buffer, l + n);
 
   if (n <= 0)
     return UNFORMAT_END_OF_INPUT;
diff --git a/src/vppinfra/unix-misc.c b/src/vppinfra/unix-misc.c
index 5559a2392fe..e73d01a15d6 100644
--- a/src/vppinfra/unix-misc.c
+++ b/src/vppinfra/unix-misc.c
@@ -158,7 +158,7 @@ unix_proc_file_contents (char *file, u8 ** result)
 
       if (bytes == 0)
 	{
-	  _vec_len (rv) = pos;
+	  vec_set_len (rv, pos);
 	  break;
 	}
       pos += bytes;
diff --git a/src/vppinfra/vec.c b/src/vppinfra/vec.c
index 805fdc02b7e..8bd0ec01f42 100644
--- a/src/vppinfra/vec.c
+++ b/src/vppinfra/vec.c
@@ -83,7 +83,7 @@ _vec_realloc (void *v, uword n_elts, uword elt_sz, uword hdr_sz, uword align,
     }
 
   CLIB_MEM_POISON (p + new_data_size, alloc_size - new_data_size);
-  _vec_len (v) = n_elts;
+  _vec_find (v)->len = n_elts;
   return v;
 }
 
diff --git a/src/vppinfra/vec_bootstrap.h b/src/vppinfra/vec_bootstrap.h
index d6451f3d172..0054802e8c1 100644
--- a/src/vppinfra/vec_bootstrap.h
+++ b/src/vppinfra/vec_bootstrap.h
@@ -116,21 +116,21 @@ vec_header_end (void *v)
   return v + vec_get_header_size (v);
 }
 
-/** \brief Number of elements in vector (lvalue-capable)
-
-   _vec_len (v) does not check for null, but can be used as an lvalue
-   (e.g. _vec_len (v) = 99).
-*/
-
-#define _vec_len(v)	(_vec_find(v)->len)
-
 /** \brief Number of elements in vector (rvalue-only, NULL tolerant)
 
     vec_len (v) checks for NULL, but cannot be used as an lvalue.
     If in doubt, use vec_len...
 */
 
+static_always_inline u32
+__vec_len (void *v)
+{
+  return _vec_find (v)->len;
+}
+
+#define _vec_len(v)	__vec_len ((void *) (v))
 #define vec_len(v)	((v) ? _vec_len(v) : 0)
+
 u32 vec_len_not_inline (void *v);
 
 /** \brief Number of data bytes in vector. */
@@ -180,10 +180,12 @@ _vec_set_len (void *v, uword len, uword elt_sz)
   else if (len > old_len)
     CLIB_MEM_POISON (v + len * elt_sz, (old_len - len) * elt_sz);
 
-  _vec_len (v) = len;
+  _vec_find (v)->len = len;
 }
 
 #define vec_set_len(v, l) _vec_set_len ((void *) v, l, _vec_elt_sz (v))
+#define vec_inc_len(v, l) vec_set_len (v, _vec_len (v) + (l))
+#define vec_dec_len(v, l) vec_set_len (v, _vec_len (v) - (l))
 
 /** \brief Reset vector length to zero
     NULL-pointer tolerant