vppinfra: add vec_set_len()

l2-flood and bier nodes reset vector length without updating it to its
effective size. Introduce a helper to do it (this allows ASAN to keep
track of the new vector size).

Type: refactor

Change-Id: I2d652550c440f0553a2b49c3ee3d37b49ebc16c3
Signed-off-by: Benoît Ganne <bganne@cisco.com>

3 files changed, 19 insertions, 10 deletions

diff --git a/src/vnet/bier/bier_lookup.c b/src/vnet/bier/bier_lookup.c
index a9fab9c80f1..9361845c992 100644
--- a/src/vnet/bier/bier_lookup.c
+++ b/src/vnet/bier/bier_lookup.c
@@ -147,10 +147,9 @@ bier_lookup (vlib_main_t * vm,
             memcpy(bbs.bbs_buckets, bh0->bh_bit_string, bbs.bbs_len);
 
             /*
-             * reset the fmask and clone storage vectors
+             * reset the fmask storage vector
              */
             vec_reset_length (blm->blm_fmasks[thread_index]);
-            vec_reset_length (blm->blm_clones[thread_index]);
 
             /*
              * Loop through the buckets in the header
@@ -225,7 +224,9 @@ bier_lookup (vlib_main_t * vm,
                                                n_clones,
 					       VLIB_BUFFER_CLONE_HEAD_SIZE);
 
-                if (num_cloned != vec_len(blm->blm_fmasks[thread_index]))
+                vec_set_len(blm->blm_clones[thread_index], num_cloned);
+
+                if (num_cloned != n_clones)
                 {
                     vlib_node_increment_counter
                         (vm, node->node_index,
diff --git a/src/vnet/l2/l2_flood.c b/src/vnet/l2/l2_flood.c
index 8d34233b520..10e087767e4 100644
--- a/src/vnet/l2/l2_flood.c
+++ b/src/vnet/l2/l2_flood.c
@@ -213,7 +213,6 @@ VLIB_NODE_FN (l2flood_node) (vlib_main_t * vm,
 	  else if (n_clones > 1)
 	    {
 	      vec_validate (msm->clones[thread_index], n_clones);
-	      vec_reset_length (msm->clones[thread_index]);
 
 	      /*
 	       * the header offset needs to be large enough to incorporate
@@ -226,6 +225,8 @@ VLIB_NODE_FN (l2flood_node) (vlib_main_t * vm,
 					    n_clones,
 					    VLIB_BUFFER_CLONE_HEAD_SIZE);
 
+	      vec_set_len (msm->clones[thread_index], n_cloned);
+
 	      if (PREDICT_FALSE (n_cloned != n_clones))
 		{
 		  b0->error = node->errors[L2FLOOD_ERROR_REPL_FAIL];
diff --git a/src/vppinfra/vec_bootstrap.h b/src/vppinfra/vec_bootstrap.h
index fec0df08143..7fb016fe8d2 100644
--- a/src/vppinfra/vec_bootstrap.h
+++ b/src/vppinfra/vec_bootstrap.h
@@ -142,12 +142,6 @@ vec_aligned_header_end (void *v, uword header_bytes, uword align)
 
 #define vec_len(v)	((v) ? _vec_len(v) : 0)
 
-/** \brief Reset vector length to zero
-    NULL-pointer tolerant
-*/
-
-#define vec_reset_length(v) do { if (v) _vec_len (v) = 0; } while (0)
-
 /** \brief Number of data bytes in vector. */
 
 #define vec_bytes(v) (vec_len (v) * sizeof (v[0]))
@@ -165,6 +159,19 @@ vec_aligned_header_end (void *v, uword header_bytes, uword align)
 /** \brief Total number of elements that can fit into vector. */
 #define vec_max_len(v) (vec_capacity(v,0) / sizeof (v[0]))
 
+/** \brief Set vector length to a user-defined value */
+#define vec_set_len(v, l) do {     \
+    ASSERT(v);                     \
+    ASSERT((l) <= vec_max_len(v)); \
+    _vec_len(v) = (l);             \
+} while (0)
+
+/** \brief Reset vector length to zero
+    NULL-pointer tolerant
+*/
+
+#define vec_reset_length(v) do { if (v) vec_set_len (v, 0); } while (0)
+
 /** \brief End (last data address) of vector. */
 #define vec_end(v)	((v) + vec_len (v))