[HICN-477] Fixed strategy get ctx that could lead to a segfault

Change-Id: Ic0d4f5a6919cb68255e788ac288d17492a6570a5
Signed-off-by: Alberto Compagno <acompagn+fdio@cisco.com>

8 files changed, 144 insertions, 165 deletions

diff --git a/hicn-plugin/src/hicn_api.c b/hicn-plugin/src/hicn_api.c
index df3365999..806de2b4e 100644
--- a/hicn-plugin/src/hicn_api.c
+++ b/hicn-plugin/src/hicn_api.c
@@ -702,7 +702,7 @@ static void vl_api_hicn_api_route_get_t_handler
 	{
 	  hicn_dpo_vft = hicn_dpo_get_vft(hicn_dpo_id->dpoi_type);
 	  hicn_dpo_ctx = hicn_dpo_vft->hicn_dpo_get_ctx(hicn_dpo_id->dpoi_index);
-	  for (int i = 0; i < hicn_dpo_ctx->entry_count; i++)
+	  for (int i = 0; hicn_dpo_ctx != NULL && i < hicn_dpo_ctx->entry_count; i++)
 	    {
 	      if (dpo_id_is_valid(&hicn_dpo_ctx->next_hops[i]))
 		{
@@ -739,7 +739,7 @@ send_route_details (vl_api_registration_t * reg,
     {
       hicn_dpo_vft = hicn_dpo_get_vft (hicn_dpo_id->dpoi_type);
       hicn_dpo_ctx = hicn_dpo_vft->hicn_dpo_get_ctx (hicn_dpo_id->dpoi_index);
-      for (int i = 0; i < hicn_dpo_ctx->entry_count; i++)
+      for (int i = 0; hicn_dpo_ctx != NULL && i < hicn_dpo_ctx->entry_count; i++)
 	{
 	  if (dpo_id_is_valid (&hicn_dpo_ctx->next_hops[i]))
 	    {
diff --git a/hicn-plugin/src/mapme_ack_node.c b/hicn-plugin/src/mapme_ack_node.c
index c2fb2b6ef..4f377447d 100644
--- a/hicn-plugin/src/mapme_ack_node.c
+++ b/hicn-plugin/src/mapme_ack_node.c
@@ -82,6 +82,13 @@ hicn_mapme_process_ack (vlib_main_t * vm, vlib_buffer_t * b,
   const hicn_dpo_vft_t *dpo_vft = hicn_dpo_get_vft (dpo->dpoi_type);
   hicn_mapme_tfib_t *tfib =
     TFIB (dpo_vft->hicn_dpo_get_ctx (dpo->dpoi_index));
+
+  if (tfib == NULL)
+    {
+      WARN ("Unable to get strategy ctx.");
+      return false;
+    }
+
   fib_seq = tfib->seq;
 
   /*
diff --git a/hicn-plugin/src/mapme_ctrl_node.c b/hicn-plugin/src/mapme_ctrl_node.c
index 57f63dbe1..3985f3073 100644
--- a/hicn-plugin/src/mapme_ctrl_node.c
+++ b/hicn-plugin/src/mapme_ctrl_node.c
@@ -132,6 +132,13 @@ hicn_mapme_process_ctrl (vlib_main_t * vm, vlib_buffer_t * b,
   const hicn_dpo_vft_t *dpo_vft = hicn_dpo_get_vft (dpo->dpoi_type);
   hicn_mapme_tfib_t *tfib =
     TFIB (dpo_vft->hicn_dpo_get_ctx (dpo->dpoi_index));
+
+  if (tfib == NULL)
+    {
+      WARN ("Unable to get strategy ctx.");
+      return false;
+    }
+
   fib_seq = tfib->seq;
 
   if (params.seq > fib_seq)
diff --git a/hicn-plugin/src/mapme_eventmgr.c b/hicn-plugin/src/mapme_eventmgr.c
index 93168d059..ef73f9550 100644
--- a/hicn-plugin/src/mapme_eventmgr.c
+++ b/hicn-plugin/src/mapme_eventmgr.c
@@ -283,13 +283,14 @@ hicn_mapme_send_updates (vlib_main_t * vm, hicn_prefix_t * prefix,
 {
   const hicn_dpo_vft_t *dpo_vft = hicn_dpo_get_vft (dpo.dpoi_type);
   hicn_mapme_tfib_t *tfib = TFIB (dpo_vft->hicn_dpo_get_ctx (dpo.dpoi_index));
-  u8 tfib_last_idx = HICN_PARAM_FIB_ENTRY_NHOPS_MAX - tfib->tfib_entry_count;
   if (!tfib)
     {
       DEBUG ("NULL TFIB entry id=%d", dpo.dpoi_index);
       return;
     }
 
+  u8 tfib_last_idx = HICN_PARAM_FIB_ENTRY_NHOPS_MAX - tfib->tfib_entry_count;
+
   mapme_params_t params = {
     .protocol = ip46_address_is_ip4 (&prefix->name)
       ? IPPROTO_IP : IPPROTO_IPV6,
diff --git a/hicn-plugin/src/route.c b/hicn-plugin/src/route.c
index 321f11940..e5758eed4 100644
--- a/hicn-plugin/src/route.c
+++ b/hicn-plugin/src/route.c
@@ -320,7 +320,7 @@ hicn_route_set_strategy (fib_prefix_t * prefix, u8 strategy_id)
 
       new_dpo_vft = hicn_dpo_get_vft_from_id (strategy_id);
 
-      if (new_dpo_vft == NULL)
+      if (new_dpo_vft == NULL || old_hicn_dpo_ctx == NULL)
 	return HICN_ERROR_STRATEGY_NOT_FOUND;
 
       /* Create a new dpo for the new strategy */
diff --git a/hicn-plugin/src/strategies/dpo_mw.c b/hicn-plugin/src/strategies/dpo_mw.c
index 41d2f2526..dfdde3681 100644
--- a/hicn-plugin/src/strategies/dpo_mw.c
+++ b/hicn-plugin/src/strategies/dpo_mw.c
@@ -95,10 +95,11 @@ hicn_dpo_strategy_mw_get_type (void)
 void
 hicn_strategy_mw_ctx_lock (dpo_id_t * dpo)
 {
-  if (dpo->dpoi_index != 0)
+  hicn_strategy_mw_ctx_t *hicn_strategy_mw_ctx =
+    (hicn_strategy_mw_ctx_t *) hicn_strategy_mw_ctx_get (dpo->dpoi_index);
+
+  if (hicn_strategy_mw_ctx != NULL)
     {
-      hicn_strategy_mw_ctx_t *hicn_strategy_mw_ctx =
-	(hicn_strategy_mw_ctx_t *) hicn_strategy_mw_ctx_get (dpo->dpoi_index);
       hicn_strategy_mw_ctx->default_ctx.locks++;
     }
 }
@@ -106,10 +107,11 @@ hicn_strategy_mw_ctx_lock (dpo_id_t * dpo)
 void
 hicn_strategy_mw_ctx_unlock (dpo_id_t * dpo)
 {
-  if (dpo->dpoi_index != 0)
+  hicn_strategy_mw_ctx_t *hicn_strategy_mw_ctx =
+    (hicn_strategy_mw_ctx_t *) hicn_strategy_mw_ctx_get (dpo->dpoi_index);
+
+  if (hicn_strategy_mw_ctx != NULL)
     {
-      hicn_strategy_mw_ctx_t *hicn_strategy_mw_ctx =
-	(hicn_strategy_mw_ctx_t *) hicn_strategy_mw_ctx_get (dpo->dpoi_index);
       hicn_strategy_mw_ctx->default_ctx.locks--;
 
       if (0 == hicn_strategy_mw_ctx->default_ctx.locks)
@@ -132,7 +134,7 @@ format_hicn_strategy_mw_ctx (u8 * s, va_list * ap)
   dpo = (hicn_strategy_mw_ctx_t *) hicn_strategy_mw_ctx_get (index);
 
   s = format (s, "hicn-mw");
-  for (i = 0; i < HICN_PARAM_FIB_ENTRY_NHOPS_MAX; i++)
+  for (i = 0; i < HICN_PARAM_FIB_ENTRY_NHOPS_MAX && dpo != NULL; i++)
     {
       u8 *buf = NULL;
       if (i < dpo->default_ctx.entry_count)
@@ -196,9 +198,10 @@ hicn_strategy_mw_ctx_get (index_t index)
   if (!pool_is_free_index (hicn_strategy_mw_ctx_pool, index))
     {
       hicn_strategy_mw_ctx =
-	(pool_elt_at_index (hicn_strategy_mw_ctx_pool, index));
+        (pool_elt_at_index (hicn_strategy_mw_ctx_pool, index));
     }
-  return &hicn_strategy_mw_ctx->default_ctx;
+
+  return (hicn_dpo_ctx_t *)hicn_strategy_mw_ctx;
 }
 
 int
@@ -207,46 +210,43 @@ hicn_strategy_mw_ctx_add_nh (const dpo_id_t * nh, index_t dpo_idx)
   hicn_strategy_mw_ctx_t *hicn_strategy_mw_ctx =
     (hicn_strategy_mw_ctx_t *) hicn_strategy_mw_ctx_get (dpo_idx);
 
-  if (hicn_strategy_mw_ctx != NULL)
+  if (hicn_strategy_mw_ctx == NULL)
     {
+      return HICN_ERROR_STRATEGY_NOT_FOUND;
+    }
 
-      int empty = hicn_strategy_mw_ctx->default_ctx.entry_count;
-
-      /* Iterate through the list of faces to add new faces */
-      for (int i = 0; i < hicn_strategy_mw_ctx->default_ctx.entry_count; i++)
-	{
-	  if (!memcmp
-	      (nh, &hicn_strategy_mw_ctx->default_ctx.next_hops[i],
-	       sizeof (dpo_id_t)))
-	    {
-	      /* If face is marked as deleted, ignore it */
-	      hicn_face_t *face =
-		hicn_dpoi_get_from_idx (hicn_strategy_mw_ctx->
-					default_ctx.next_hops[i].dpoi_index);
-	      if (face->shared.flags & HICN_FACE_FLAGS_DELETED)
-		{
-		  continue;
-		}
-	      return HICN_ERROR_DPO_CTX_NHOPS_EXISTS;
-	    }
-	}
+  int empty = hicn_strategy_mw_ctx->default_ctx.entry_count;
 
-      /* Get an empty place */
-      if (empty > HICN_PARAM_FIB_ENTRY_NHOPS_MAX)
-	{
-	  return HICN_ERROR_DPO_CTX_NHOPS_NS;
-	}
-      if (PREDICT_FALSE (empty > HICN_PARAM_FIB_ENTRY_NHOPS_MAX))
-	{
-	  return HICN_ERROR_DPO_CTX_NHOPS_NS;
-	}
-      clib_memcpy (&hicn_strategy_mw_ctx->default_ctx.next_hops[empty], nh,
-		   sizeof (dpo_id_t));
-      hicn_strategy_mw_ctx->default_ctx.entry_count++;
+  /* Iterate through the list of faces to add new faces */
+  for (int i = 0; i < hicn_strategy_mw_ctx->default_ctx.entry_count; i++)
+    {
+      if (!memcmp
+          (nh, &hicn_strategy_mw_ctx->default_ctx.next_hops[i],
+           sizeof (dpo_id_t)))
+        {
+          /* If face is marked as deleted, ignore it */
+          hicn_face_t *face =
+            hicn_dpoi_get_from_idx (hicn_strategy_mw_ctx->
+                                    default_ctx.next_hops[i].dpoi_index);
+          if (face->shared.flags & HICN_FACE_FLAGS_DELETED)
+            {
+              continue;
+            }
+          return HICN_ERROR_DPO_CTX_NHOPS_EXISTS;
+        }
+    }
 
-      return HICN_ERROR_NONE;
+  /* Get an empty place */
+  if (empty > HICN_PARAM_FIB_ENTRY_NHOPS_MAX)
+    {
+      return HICN_ERROR_DPO_CTX_NHOPS_NS;
     }
-  return HICN_ERROR_DPO_CTX_NOT_FOUND;
+
+  clib_memcpy (&hicn_strategy_mw_ctx->default_ctx.next_hops[empty], nh,
+               sizeof (dpo_id_t));
+  hicn_strategy_mw_ctx->default_ctx.entry_count++;
+
+  return HICN_ERROR_NONE;
 }
 
 int
@@ -256,52 +256,32 @@ hicn_strategy_mw_ctx_del_nh (hicn_face_id_t face_id, index_t dpo_idx,
   hicn_strategy_mw_ctx_t *hicn_strategy_mw_ctx =
     (hicn_strategy_mw_ctx_t *) hicn_strategy_mw_ctx_get (dpo_idx);
   int ret = HICN_ERROR_DPO_CTX_NOT_FOUND;
-  int nh_id = ~0;
   dpo_id_t invalid = NEXT_HOP_INVALID;
 
   if (hicn_strategy_mw_ctx != NULL)
-    {
-      for (int i = 0; i < hicn_strategy_mw_ctx->default_ctx.entry_count; i++)
-	{
-	  if (hicn_strategy_mw_ctx->default_ctx.next_hops[i].dpoi_index ==
-	      face_id)
-	    {
-	      nh_id = i;
-	      hicn_face_unlock (&hicn_strategy_mw_ctx->default_ctx.
-				next_hops[i]);
-	      hicn_strategy_mw_ctx->default_ctx.next_hops[i] = invalid;
-	      hicn_strategy_mw_ctx->default_ctx.entry_count--;
-        ret = HICN_ERROR_NONE;
-	    }
-	}
+    return HICN_ERROR_STRATEGY_NOT_FOUND;
 
-      if (0 == hicn_strategy_mw_ctx->default_ctx.entry_count)
-	{
-	  fib_table_entry_special_remove (HICN_FIB_TABLE, fib_pfx,
-					  FIB_SOURCE_PLUGIN_HI);
-	}
-    }
-  else
+  for (int i = 0; i < hicn_strategy_mw_ctx->default_ctx.entry_count; i++)
     {
-      ret = HICN_ERROR_DPO_CTX_NOT_FOUND;
+      if (hicn_strategy_mw_ctx->default_ctx.next_hops[i].dpoi_index ==
+          face_id)
+        {
+          hicn_face_unlock (&hicn_strategy_mw_ctx->default_ctx.
+                            next_hops[i]);
+          hicn_strategy_mw_ctx->default_ctx.entry_count--;
+          hicn_strategy_mw_ctx->default_ctx.next_hops[i] = hicn_strategy_mw_ctx->default_ctx.next_hops[hicn_strategy_mw_ctx->default_ctx.entry_count];
+          hicn_strategy_mw_ctx->default_ctx.next_hops[hicn_strategy_mw_ctx->default_ctx.entry_count] = invalid;
+          ret = HICN_ERROR_NONE;
+          break;
+        }
     }
 
-  /*
-   * Remove any possible hole in the arrays of dpos
-   */
-  if (hicn_strategy_mw_ctx->default_ctx.entry_count > 0 && nh_id != ~0
-      && nh_id < hicn_strategy_mw_ctx->default_ctx.entry_count - 1)
+  if (0 == hicn_strategy_mw_ctx->default_ctx.entry_count)
     {
-      int i;
-      for (i = nh_id; i < hicn_strategy_mw_ctx->default_ctx.entry_count; i++)
-	{
-	  clib_memcpy (&hicn_strategy_mw_ctx->default_ctx.next_hops[i],
-		       &hicn_strategy_mw_ctx->default_ctx.next_hops[i + 1],
-		       sizeof (dpo_id_t));
-	}
-      /* Set as invalid the last dpo */
-      hicn_strategy_mw_ctx->default_ctx.next_hops[i] = invalid;
+      fib_table_entry_special_remove (HICN_FIB_TABLE, fib_pfx,
+                                      FIB_SOURCE_PLUGIN_HI);
     }
+
   return ret;
 }
 
diff --git a/hicn-plugin/src/strategies/dpo_rr.c b/hicn-plugin/src/strategies/dpo_rr.c
index 447a25c52..4cddd513c 100644
--- a/hicn-plugin/src/strategies/dpo_rr.c
+++ b/hicn-plugin/src/strategies/dpo_rr.c
@@ -95,10 +95,11 @@ hicn_dpo_strategy_rr_get_type (void)
 void
 hicn_strategy_rr_ctx_lock (dpo_id_t * dpo)
 {
-  if (dpo->dpoi_index != 0)
+  hicn_strategy_rr_ctx_t *hicn_strategy_rr_ctx =
+    (hicn_strategy_rr_ctx_t *) hicn_strategy_rr_ctx_get (dpo->dpoi_index);
+
+  if (hicn_strategy_rr_ctx != NULL)
     {
-      hicn_strategy_rr_ctx_t *hicn_strategy_rr_ctx =
-	(hicn_strategy_rr_ctx_t *) hicn_strategy_rr_ctx_get (dpo->dpoi_index);
       hicn_strategy_rr_ctx->default_ctx.locks++;
     }
 }
@@ -106,10 +107,10 @@ hicn_strategy_rr_ctx_lock (dpo_id_t * dpo)
 void
 hicn_strategy_rr_ctx_unlock (dpo_id_t * dpo)
 {
-  if (dpo->dpoi_index != 0)
+  hicn_strategy_rr_ctx_t *hicn_strategy_rr_ctx =
+    (hicn_strategy_rr_ctx_t *) hicn_strategy_rr_ctx_get (dpo->dpoi_index);
+  if (hicn_strategy_rr_ctx != NULL)
     {
-      hicn_strategy_rr_ctx_t *hicn_strategy_rr_ctx =
-	(hicn_strategy_rr_ctx_t *) hicn_strategy_rr_ctx_get (dpo->dpoi_index);
       hicn_strategy_rr_ctx->default_ctx.locks--;
 
       if (0 == hicn_strategy_rr_ctx->default_ctx.locks)
@@ -135,7 +136,7 @@ format_hicn_strategy_rr_ctx (u8 * s, va_list * ap)
     format (s, "hicn-rr, next hop Face %d",
 	    dpo->default_ctx.next_hops[dpo->current_nhop].dpoi_index);
 
-  for (i = 0; i < HICN_PARAM_FIB_ENTRY_NHOPS_MAX; i++)
+  for (i = 0; i < HICN_PARAM_FIB_ENTRY_NHOPS_MAX && dpo != NULL; i++)
     {
       u8 *buf = NULL;
       if (i < dpo->default_ctx.entry_count)
@@ -201,7 +202,7 @@ hicn_strategy_rr_ctx_get (index_t index)
       hicn_strategy_rr_ctx =
 	(pool_elt_at_index (hicn_strategy_rr_ctx_pool, index));
     }
-  return &hicn_strategy_rr_ctx->default_ctx;
+  return (hicn_dpo_ctx_t *)hicn_strategy_rr_ctx;
 }
 
 int
@@ -210,46 +211,43 @@ hicn_strategy_rr_ctx_add_nh (const dpo_id_t * nh, index_t dpo_idx)
   hicn_strategy_rr_ctx_t *hicn_strategy_rr_ctx =
     (hicn_strategy_rr_ctx_t *) hicn_strategy_rr_ctx_get (dpo_idx);
 
-  if (hicn_strategy_rr_ctx != NULL)
+  if (hicn_strategy_rr_ctx == NULL)
     {
+      return HICN_ERROR_STRATEGY_NOT_FOUND;
+    }
 
-      int empty = hicn_strategy_rr_ctx->default_ctx.entry_count;
-
-      /* Iterate through the list of faces to add new faces */
-      for (int i = 0; i < hicn_strategy_rr_ctx->default_ctx.entry_count; i++)
-	{
-	  if (!memcmp
-	      (nh, &hicn_strategy_rr_ctx->default_ctx.next_hops[i],
-	       sizeof (dpo_id_t)))
-	    {
-	      /* If face is marked as deleted, ignore it */
-	      hicn_face_t *face =
-		hicn_dpoi_get_from_idx (hicn_strategy_rr_ctx->default_ctx.
-					next_hops[i].dpoi_index);
-	      if (face->shared.flags & HICN_FACE_FLAGS_DELETED)
-		{
-		  continue;
-		}
-	      return HICN_ERROR_DPO_CTX_NHOPS_EXISTS;
-	    }
-	}
+  int empty = hicn_strategy_rr_ctx->default_ctx.entry_count;
 
-      /* Get an empty place */
-      if (empty > HICN_PARAM_FIB_ENTRY_NHOPS_MAX)
-	{
-	  return HICN_ERROR_DPO_CTX_NHOPS_NS;
-	}
-      if (PREDICT_FALSE (empty > HICN_PARAM_FIB_ENTRY_NHOPS_MAX))
-	{
-	  return HICN_ERROR_DPO_CTX_NHOPS_NS;
-	}
-      clib_memcpy (&hicn_strategy_rr_ctx->default_ctx.next_hops[empty], nh,
-		   sizeof (dpo_id_t));
-      hicn_strategy_rr_ctx->default_ctx.entry_count++;
+  /* Iterate through the list of faces to add new faces */
+  for (int i = 0; i < hicn_strategy_rr_ctx->default_ctx.entry_count; i++)
+    {
+      if (!memcmp
+          (nh, &hicn_strategy_rr_ctx->default_ctx.next_hops[i],
+           sizeof (dpo_id_t)))
+        {
+          /* If face is marked as deleted, ignore it */
+          hicn_face_t *face =
+            hicn_dpoi_get_from_idx (hicn_strategy_rr_ctx->default_ctx.
+                                    next_hops[i].dpoi_index);
+          if (face->shared.flags & HICN_FACE_FLAGS_DELETED)
+            {
+              continue;
+            }
+          return HICN_ERROR_DPO_CTX_NHOPS_EXISTS;
+        }
+    }
 
-      return HICN_ERROR_NONE;
+  /* Get an empty place */
+  if (empty > HICN_PARAM_FIB_ENTRY_NHOPS_MAX)
+    {
+      return HICN_ERROR_DPO_CTX_NHOPS_NS;
     }
-  return HICN_ERROR_DPO_CTX_NOT_FOUND;
+
+  clib_memcpy (&hicn_strategy_rr_ctx->default_ctx.next_hops[empty], nh,
+               sizeof (dpo_id_t));
+  hicn_strategy_rr_ctx->default_ctx.entry_count++;
+
+  return HICN_ERROR_NONE;
 }
 
 int
@@ -258,52 +256,35 @@ hicn_strategy_rr_ctx_del_nh (hicn_face_id_t face_id, index_t dpo_idx,
 {
   hicn_strategy_rr_ctx_t *hicn_strategy_rr_ctx =
     (hicn_strategy_rr_ctx_t *) hicn_strategy_rr_ctx_get (dpo_idx);
-  int ret = HICN_ERROR_NONE;
-  int nh_id = ~0;
+  int ret = HICN_ERROR_DPO_CTX_NOT_FOUND;
   dpo_id_t invalid = NEXT_HOP_INVALID;
 
-  if (hicn_strategy_rr_ctx != NULL)
+  if (hicn_strategy_rr_ctx == NULL)
     {
-      for (int i = 0; i < hicn_strategy_rr_ctx->default_ctx.entry_count; i++)
-	{
-	  if (hicn_strategy_rr_ctx->default_ctx.next_hops[i].dpoi_index ==
-	      face_id)
-	    {
-	      nh_id = i;
-	      hicn_face_unlock (&hicn_strategy_rr_ctx->
-				default_ctx.next_hops[i]);
-	      hicn_strategy_rr_ctx->default_ctx.next_hops[i] = invalid;
-	      hicn_strategy_rr_ctx->default_ctx.entry_count--;
-	    }
-	}
-
-      if (0 == hicn_strategy_rr_ctx->default_ctx.entry_count)
-	{
-	  fib_table_entry_special_remove (HICN_FIB_TABLE, fib_pfx,
-					  FIB_SOURCE_PLUGIN_HI);
-	}
+      return HICN_ERROR_STRATEGY_NOT_FOUND;
     }
-  else
+
+  for (int i = 0; i < hicn_strategy_rr_ctx->default_ctx.entry_count; i++)
     {
-      ret = HICN_ERROR_DPO_CTX_NOT_FOUND;
+      if (hicn_strategy_rr_ctx->default_ctx.next_hops[i].dpoi_index ==
+          face_id)
+        {
+          hicn_face_unlock (&hicn_strategy_rr_ctx->
+                            default_ctx.next_hops[i]);
+          hicn_strategy_rr_ctx->default_ctx.entry_count--;
+          hicn_strategy_rr_ctx->default_ctx.next_hops[i] = hicn_strategy_rr_ctx->default_ctx.next_hops[hicn_strategy_rr_ctx->default_ctx.entry_count];
+          hicn_strategy_rr_ctx->default_ctx.next_hops[hicn_strategy_rr_ctx->default_ctx.entry_count] = invalid;
+          ret = HICN_ERROR_NONE;
+          break;
+        }
     }
 
-  /*
-   * Remove any possible hole in the arrays of dpos
-   */
-  if (hicn_strategy_rr_ctx->default_ctx.entry_count > 0 && nh_id != ~0
-      && nh_id < hicn_strategy_rr_ctx->default_ctx.entry_count - 1)
+  if (0 == hicn_strategy_rr_ctx->default_ctx.entry_count)
     {
-      int i;
-      for (i = nh_id; i < hicn_strategy_rr_ctx->default_ctx.entry_count; i++)
-	{
-	  clib_memcpy (&hicn_strategy_rr_ctx->default_ctx.next_hops[i],
-		       &hicn_strategy_rr_ctx->default_ctx.next_hops[i + 1],
-		       sizeof (dpo_id_t));
-	}
-      /* Set as invalid the last dpo */
-      hicn_strategy_rr_ctx->default_ctx.next_hops[i] = invalid;
+      fib_table_entry_special_remove (HICN_FIB_TABLE, fib_pfx,
+                                      FIB_SOURCE_PLUGIN_HI);
     }
+
   return ret;
 }
 
diff --git a/hicn-plugin/src/strategies/strategy_mw.c b/hicn-plugin/src/strategies/strategy_mw.c
index d5ff87303..40e062bd8 100644
--- a/hicn-plugin/src/strategies/strategy_mw.c
+++ b/hicn-plugin/src/strategies/strategy_mw.c
@@ -73,6 +73,9 @@ hicn_select_next_hop_mw (index_t dpo_idx, int *nh_idx, dpo_id_t ** outface)
   hicn_strategy_mw_ctx_t *hicn_strategy_mw_ctx =
     (hicn_strategy_mw_ctx_t *) hicn_strategy_mw_ctx_get (dpo_idx);
 
+  if(hicn_strategy_mw_ctx == NULL)
+    return HICN_ERROR_STRATEGY_NOT_FOUND;
+
   u8 next_hop_index = 0;
   for (int i = 0; i < hicn_strategy_mw_ctx->default_ctx.entry_count; i++)
     {