Fix failure during enable/disable of features

vnet_feature_enable_disable_with_index() checks the
return status of vnet_config_{add,del}_feature().
If the config string heap index returned is the same
index that was in use prior to the add/delete, it is
concluded that a failure occurred and processing of
the feature stops.

Sometimes the config index that is returned
can legitimately be the same index that was in used
before the add/delete. The old list of features can
have its heap entry deallocated before a new entry for
the new list is allocated. The heap entry for the new
list can be the entry that was deallocated while
deleting the old one.

Make vnet_config_{add,del}_feature() return ~0 on
failure. Look for that return value as an indication
that an error occurred in
vnet_enable_disable_feature_by_index().

Change-Id: I88bb3ff88a76971c1b5e5ece74784ce8ba78373c
Signed-off-by: Matthew Smith <mgsmith@netgate.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/src/vnet/config.c b/src/vnet/config.c
index 03189d77cd5..26b0cad6055 100644
--- a/src/vnet/config.c
+++ b/src/vnet/config.c
@@ -247,7 +247,7 @@ vnet_config_add_feature (vlib_main_t * vm,
   u32 node_index = vec_elt (cm->node_index_by_feature_index, feature_index);
 
   if (node_index == ~0)		// feature node does not exist
-    return config_string_heap_index;	// return original config index
+    return ~0;
 
   if (config_string_heap_index == ~0)
     {
@@ -330,7 +330,7 @@ vnet_config_del_feature (vlib_main_t * vm,
 
   /* Feature not found. */
   if (f >= vec_end (old->features))
-    return config_string_heap_index;	// return original config index
+    return ~0;
 
   new_features = duplicate_feature_vector (old->features);
   f = new_features + (f - old->features);