stats: fix state counter removal

Avoid using vec_del1() for directory vector to keep indexes valid all
the time.

There are state counters for each slave in LACP bond mode which can be
dynamically created and removed. Vector index is used to access these
counters. But also vec_del1() is used to remove counter from vector.
This function changes the index of the last element, so after this we
are unable to access ex-last element using old index.

As a result it is not possible to add-del-add two interfaces to the LACP
bond:

DBGvpp# create bond mode lacp
BondEthernet0
DBGvpp# create packet-generator interface pg1
DBGvpp# create packet-generator interface pg2
DBGvpp# bond add BondEthernet0 pg1
DBGvpp# bond add BondEthernet0 pg2
DBGvpp# bond del pg1
DBGvpp# bond del pg2
DBGvpp# bond add BondEthernet0 pg1
DBGvpp# bond add BondEthernet0 pg2
bond add: /if/lacp/1/3/partner-state is already register

Type: fix

Signed-off-by: Vladimir Isaev <visaev@netgate.com>
Change-Id: I2c86e13905eefdef6233369cd4ab5c1b53d123bd
(cherry picked from commit 72e31bc2d9b910147c09e1c329713fccc873a018)

6 files changed, 128 insertions, 45 deletions

diff --git a/src/vpp-api/client/stat_client.c b/src/vpp-api/client/stat_client.c
index 9a7a0e59daa..9c6ff33c2d1 100644
--- a/src/vpp-api/client/stat_client.c
+++ b/src/vpp-api/client/stat_client.c
@@ -274,6 +274,9 @@ copy_data (stat_segment_directory_entry_t * ep, stat_client_main_t * sm)
 	}
       break;
 
+    case STAT_DIR_TYPE_EMPTY:
+      break;
+
     default:
       fprintf (stderr, "Unknown type: %d\n", ep->type);
     }
diff --git a/src/vpp/app/vpp_get_stats.c b/src/vpp/app/vpp_get_stats.c
index c00fb835d1c..d13e4d9b2b2 100644
--- a/src/vpp/app/vpp_get_stats.c
+++ b/src/vpp/app/vpp_get_stats.c
@@ -89,6 +89,9 @@ stat_poll_loop (u8 ** patterns)
 	      fformat (stdout, "%.2f %s\n", res[i].scalar_value, res[i].name);
 	      break;
 
+	    case STAT_DIR_TYPE_EMPTY:
+	      break;
+
 	    default:
 	      printf ("Unknown value\n");
 	      ;
@@ -233,6 +236,9 @@ reconnect:
 			   res[i].name);
 	      break;
 
+	    case STAT_DIR_TYPE_EMPTY:
+	      break;
+
 	    default:
 	      ;
 	    }
diff --git a/src/vpp/app/vpp_prometheus_export.c b/src/vpp/app/vpp_prometheus_export.c
index 06f1a9169cd..99944917766 100644
--- a/src/vpp/app/vpp_prometheus_export.c
+++ b/src/vpp/app/vpp_prometheus_export.c
@@ -112,6 +112,9 @@ retry:
 		   res[i].scalar_value);
 	  break;
 
+	case STAT_DIR_TYPE_EMPTY:
+	  break;
+
 	default:
 	  fformat (stderr, "Unknown value %d\n", res[i].type);
 	  ;
diff --git a/src/vpp/stats/stat_segment.c b/src/vpp/stats/stat_segment.c
index 8eeb38387d7..9e117657467 100644
--- a/src/vpp/stats/stat_segment.c
+++ b/src/vpp/stats/stat_segment.c
@@ -60,24 +60,17 @@ vlib_stats_push_heap (void *old)
 }
 
 static u32
-lookup_or_create_hash_index (u8 * name, u32 next_vector_index)
+lookup_hash_index (u8 * name)
 {
   stat_segment_main_t *sm = &stat_segment_main;
-  u32 index;
+  u32 index = STAT_SEGMENT_INDEX_INVALID;
   hash_pair_t *hp;
 
   /* Must be called in the context of the main heap */
   ASSERT (clib_mem_get_heap () != sm->heap);
 
   hp = hash_get_pair (sm->directory_vector_by_name, name);
-  if (!hp)
-    {
-      /* we allocate our private copy of 'name' */
-      hash_set (sm->directory_vector_by_name, format (0, "%s%c", name, 0),
-		next_vector_index);
-      index = next_vector_index;
-    }
-  else
+  if (hp)
     {
       index = hp->value[0];
     }
@@ -85,6 +78,76 @@ lookup_or_create_hash_index (u8 * name, u32 next_vector_index)
   return index;
 }
 
+static void
+create_hash_index (u8 * name, u32 index)
+{
+  stat_segment_main_t *sm = &stat_segment_main;
+
+  /* Must be called in the context of the main heap */
+  ASSERT (clib_mem_get_heap () != sm->heap);
+
+  hash_set (sm->directory_vector_by_name, format (0, "%s%c", name, 0), index);
+}
+
+static u32
+vlib_stats_get_next_vector_index ()
+{
+  stat_segment_main_t *sm = &stat_segment_main;
+  u32 next_vector_index = vec_len (sm->directory_vector);
+
+  ssize_t i;
+  vec_foreach_index_backwards (i, sm->directory_vector)
+  {
+    if (sm->directory_vector[i].type == STAT_DIR_TYPE_EMPTY)
+      {
+	next_vector_index = i;
+	break;
+      }
+  }
+
+  return next_vector_index;
+}
+
+static u32
+vlib_stats_create_counter (stat_segment_directory_entry_t * e, void *oldheap)
+{
+  stat_segment_main_t *sm = &stat_segment_main;
+
+  ASSERT (clib_mem_get_heap () == sm->heap);
+
+  u32 index = vlib_stats_get_next_vector_index ();
+
+  clib_mem_set_heap (oldheap);
+  create_hash_index ((u8 *) e->name, index);
+  clib_mem_set_heap (sm->heap);
+
+  vec_validate (sm->directory_vector, index);
+  sm->directory_vector[index] = *e;
+
+  return index;
+}
+
+static void
+vlib_stats_delete_counter (u32 index, void *oldheap)
+{
+  stat_segment_main_t *sm = &stat_segment_main;
+  stat_segment_directory_entry_t *e;
+
+  ASSERT (clib_mem_get_heap () == sm->heap);
+
+  if (index > vec_len (sm->directory_vector))
+    return;
+
+  e = &sm->directory_vector[index];
+
+  clib_mem_set_heap (oldheap);
+  hash_unset (sm->directory_vector_by_name, &e->name);
+  clib_mem_set_heap (sm->heap);
+
+  memset (e, 0, sizeof (*e));
+  e->type = STAT_DIR_TYPE_EMPTY;
+}
+
 void
 vlib_stats_pop_heap (void *cm_arg, void *oldheap, u32 cindex,
 		     stat_directory_type_t type)
@@ -109,20 +172,18 @@ vlib_stats_pop_heap (void *cm_arg, void *oldheap, u32 cindex,
   /* Lookup hash-table is on the main heap */
   stat_segment_name =
     cm->stat_segment_name ? cm->stat_segment_name : cm->name;
-  u32 next_vector_index = vec_len (sm->directory_vector);
   clib_mem_set_heap (oldheap);	/* Exit stats segment */
-  u32 vector_index = lookup_or_create_hash_index ((u8 *) stat_segment_name,
-						  next_vector_index);
+  u32 vector_index = lookup_hash_index ((u8 *) stat_segment_name);
   /* Back to stats segment */
   clib_mem_set_heap (sm->heap);	/* Re-enter stat segment */
 
 
   /* Update the vector */
-  if (vector_index == next_vector_index)
+  if (vector_index == STAT_SEGMENT_INDEX_INVALID)
     {				/* New */
       strncpy (e.name, stat_segment_name, 128 - 1);
       e.type = type;
-      vec_add1 (sm->directory_vector, e);
+      vector_index = vlib_stats_create_counter (&e, oldheap);
     }
 
   stat_segment_directory_entry_t *ep = &sm->directory_vector[vector_index];
@@ -168,23 +229,19 @@ vlib_stats_register_error_index (void *oldheap, u8 * name, u64 * em_vec,
   ASSERT (shared_header);
 
   vlib_stat_segment_lock ();
-  u32 next_vector_index = vec_len (sm->directory_vector);
   clib_mem_set_heap (oldheap);	/* Exit stats segment */
-
-  u32 vector_index = lookup_or_create_hash_index (name,
-						  next_vector_index);
-
+  u32 vector_index = lookup_hash_index (name);
   /* Back to stats segment */
   clib_mem_set_heap (sm->heap);	/* Re-enter stat segment */
 
-  if (next_vector_index == vector_index)
+  if (vector_index == STAT_SEGMENT_INDEX_INVALID)
     {
       memcpy (e.name, name, vec_len (name));
       e.name[vec_len (name)] = '\0';
       e.type = STAT_DIR_TYPE_ERROR_INDEX;
       e.offset = index;
       e.offset_vector = 0;
-      vec_add1 (sm->directory_vector, e);
+      vector_index = vlib_stats_create_counter (&e, oldheap);
 
       /* Warn clients to refresh any pointers they might be holding */
       shared_header->directory_offset =
@@ -385,6 +442,10 @@ format_stat_dir_entry (u8 * s, va_list * args)
       type_name = "NameVector";
       break;
 
+    case STAT_DIR_TYPE_EMPTY:
+      type_name = "empty";
+      break;
+
     default:
       type_name = "illegal!";
       break;
@@ -418,6 +479,11 @@ show_stat_segment_command_fn (vlib_main_t * vm,
 
   for (i = 0; i < vec_len (show_data); i++)
     {
+      stat_segment_directory_entry_t *ep = vec_elt_at_index (show_data, i);
+
+      if (ep->type == STAT_DIR_TYPE_EMPTY)
+	continue;
+
       vlib_cli_output (vm, "%-100U", format_stat_dir_entry,
 		       vec_elt_at_index (show_data, i));
     }
@@ -769,21 +835,18 @@ stat_segment_register_gauge (u8 * name, stat_segment_update_fn update_fn,
 
   ASSERT (shared_header);
 
-  u32 next_vector_index = vec_len (sm->directory_vector);
-  u32 vector_index = lookup_or_create_hash_index (name,
-						  next_vector_index);
-
-  if (vector_index < next_vector_index)	/* Already registered */
-    return clib_error_return (0, "%v is alreadty registered", name);
+  u32 vector_index = lookup_hash_index (name);
 
-  oldheap = vlib_stats_push_heap (NULL);
-  vlib_stat_segment_lock ();
+  if (vector_index != STAT_SEGMENT_INDEX_INVALID)	/* Already registered */
+    return clib_error_return (0, "%v is already registered", name);
 
   memset (&e, 0, sizeof (e));
   e.type = STAT_DIR_TYPE_SCALAR_INDEX;
-
   memcpy (e.name, name, vec_len (name));
-  vec_add1 (sm->directory_vector, e);
+
+  oldheap = vlib_stats_push_heap (NULL);
+  vlib_stat_segment_lock ();
+  vector_index = vlib_stats_create_counter (&e, oldheap);
 
   shared_header->directory_offset =
     stat_segment_offset (shared_header, sm->directory_vector);
@@ -795,7 +858,7 @@ stat_segment_register_gauge (u8 * name, stat_segment_update_fn update_fn,
   pool_get (sm->gauges, gauge);
   gauge->fn = update_fn;
   gauge->caller_index = caller_index;
-  gauge->directory_index = next_vector_index;
+  gauge->directory_index = vector_index;
 
   return NULL;
 }
@@ -811,21 +874,19 @@ stat_segment_register_state_counter (u8 * name, u32 * index)
   ASSERT (shared_header);
   ASSERT (vlib_get_thread_index () == 0);
 
-  u32 next_vector_index = vec_len (sm->directory_vector);
-  u32 vector_index = lookup_or_create_hash_index (name,
-						  next_vector_index);
+  u32 vector_index = lookup_hash_index (name);
 
-  if (vector_index < next_vector_index)	/* Already registered */
+  if (vector_index != STAT_SEGMENT_INDEX_INVALID)	/* Already registered */
     return clib_error_return (0, "%v is already registered", name);
 
-  oldheap = vlib_stats_push_heap (NULL);
-  vlib_stat_segment_lock ();
-
   memset (&e, 0, sizeof (e));
   e.type = STAT_DIR_TYPE_SCALAR_INDEX;
-
   memcpy (e.name, name, vec_len (name));
-  vec_add1 (sm->directory_vector, e);
+
+  oldheap = vlib_stats_push_heap (NULL);
+  vlib_stat_segment_lock ();
+
+  vector_index = vlib_stats_create_counter (&e, oldheap);
 
   shared_header->directory_offset =
     stat_segment_offset (shared_header, sm->directory_vector);
@@ -833,7 +894,7 @@ stat_segment_register_state_counter (u8 * name, u32 * index)
   vlib_stat_segment_unlock ();
   clib_mem_set_heap (oldheap);
 
-  *index = next_vector_index;
+  *index = vector_index;
   return 0;
 }
 
@@ -843,6 +904,7 @@ stat_segment_deregister_state_counter (u32 index)
   stat_segment_main_t *sm = &stat_segment_main;
   stat_segment_shared_header_t *shared_header = sm->shared_header;
   stat_segment_directory_entry_t *e;
+  void *oldheap;
 
   ASSERT (shared_header);
 
@@ -853,8 +915,14 @@ stat_segment_deregister_state_counter (u32 index)
   if (e->type != STAT_DIR_TYPE_SCALAR_INDEX)
     return clib_error_return (0, "%u index cannot be deleted", index);
 
-  hash_unset (sm->directory_vector_by_name, &e->name);
-  vec_del1 (sm->directory_vector, index);
+  oldheap = vlib_stats_push_heap (NULL);
+  vlib_stat_segment_lock ();
+
+  vlib_stats_delete_counter (index, oldheap);
+
+  vlib_stat_segment_unlock ();
+  clib_mem_set_heap (oldheap);
+
   return 0;
 }
 
diff --git a/src/vpp/stats/stat_segment.h b/src/vpp/stats/stat_segment.h
index 83d233479a8..28e9ca3f778 100644
--- a/src/vpp/stats/stat_segment.h
+++ b/src/vpp/stats/stat_segment.h
@@ -64,6 +64,8 @@ typedef enum
 /* Shared segment memory layout version */
 #define STAT_SEGMENT_VERSION		1
 
+#define STAT_SEGMENT_INDEX_INVALID	UINT32_MAX
+
 static inline uint64_t
 stat_segment_offset (void *start, void *data)
 {
diff --git a/src/vpp/stats/stat_segment_shared.h b/src/vpp/stats/stat_segment_shared.h
index 719cf59c5b1..982bddd66b6 100644
--- a/src/vpp/stats/stat_segment_shared.h
+++ b/src/vpp/stats/stat_segment_shared.h
@@ -24,6 +24,7 @@ typedef enum
   STAT_DIR_TYPE_COUNTER_VECTOR_COMBINED,
   STAT_DIR_TYPE_ERROR_INDEX,
   STAT_DIR_TYPE_NAME_VECTOR,
+  STAT_DIR_TYPE_EMPTY,
 } stat_directory_type_t;
 
 typedef struct