lib: fix prefix list installation

Based on the function `prefix_list_entry_add` and
`prefix_list_entry_delete` it was created two functions to replicate
its functionality without the assumption we are always alocating a new
prefix list entry.

Since the prefix list entry is stored in the YANG private data
structures, we want to avoid the allocation/free of memory that is
hold by the schema.

Every time a prefix list entry values change we must call
`prefix_list_entry_update_start` to uninstall the entry from prefix
list internal structures and then call
`prefix_list_entry_update_finish` to put them back.

The variable `installed` in the prefix list entry tracks the
installation status of the internal structure. It is possible that a
user unconfigures or forgets to add a `prefix` value and so we can't
install the entry until then.

Signed-off-by: Rafael Zalamena <rzalamena@opensourcerouting.org>

lib/filter_nb.c

@@ -838,6 +838,7 @@ static int lib_prefix_list_entry_create(struct nb_cb_create_args *args)
 	ple->pl = pl;
 	ple->any = 1;
 	ple->seq = yang_dnode_get_uint32(args->dnode, "./sequence");
+	nb_running_set_entry(args->dnode, ple);
 
 	return NB_OK;
 }
@@ -850,7 +851,10 @@ static int lib_prefix_list_entry_destroy(struct nb_cb_destroy_args *args)
 		return NB_OK;
 
 	ple = nb_running_unset_entry(args->dnode);
-	prefix_list_entry_delete(ple->pl, ple, 1);
+	if (ple->installed)
+		prefix_list_entry_delete(ple->pl, ple, 0);
+	else
+		prefix_list_entry_free(ple);
 
 	return NB_OK;
 }
@@ -867,12 +871,19 @@ static int lib_prefix_list_entry_action_modify(struct nb_cb_modify_args *args)
 		return NB_OK;
 
 	ple = nb_running_get_entry(args->dnode, NULL, true);
+
+	/* Start prefix entry update procedure. */
+	prefix_list_entry_update_start(ple);
+
 	action_str = yang_dnode_get_string(args->dnode, NULL);
 	if (strcmp(action_str, "permit") == 0)
 		ple->type = PREFIX_PERMIT;
 	else
 		ple->type = PREFIX_DENY;
 
+	/* Finish prefix entry update procedure. */
+	prefix_list_entry_update_finish(ple);
+
 	return NB_OK;
 }
 
@@ -888,8 +899,15 @@ lib_prefix_list_entry_ipv4_prefix_modify(struct nb_cb_modify_args *args)
 		return NB_OK;
 
 	ple = nb_running_get_entry(args->dnode, NULL, true);
+
+	/* Start prefix entry update procedure. */
+	prefix_list_entry_update_start(ple);
+
 	yang_dnode_get_prefix(&ple->prefix, args->dnode, NULL);
 
+	/* Finish prefix entry update procedure. */
+	prefix_list_entry_update_finish(ple);
+
 	return NB_OK;
 }
 
@@ -902,9 +920,16 @@ lib_prefix_list_entry_ipv4_prefix_destroy(struct nb_cb_destroy_args *args)
 		return NB_OK;
 
 	ple = nb_running_get_entry(args->dnode, NULL, true);
+
+	/* Start prefix entry update procedure. */
+	prefix_list_entry_update_start(ple);
+
 	memset(&ple->prefix, 0, sizeof(ple->prefix));
 	ple->any = 1;
 
+	/* Finish prefix entry update procedure. */
+	prefix_list_entry_update_finish(ple);
+
 	return NB_OK;
 }
 
@@ -924,8 +949,15 @@ static int lib_prefix_list_entry_ipv4_prefix_length_greater_or_equal_modify(
 		return NB_OK;
 
 	ple = nb_running_get_entry(args->dnode, NULL, true);
+
+	/* Start prefix entry update procedure. */
+	prefix_list_entry_update_start(ple);
+
 	ple->ge = yang_dnode_get_uint8(args->dnode, NULL);
 
+	/* Finish prefix entry update procedure. */
+	prefix_list_entry_update_finish(ple);
+
 	return NB_OK;
 }
 
@@ -938,8 +970,15 @@ static int lib_prefix_list_entry_ipv4_prefix_length_greater_or_equal_destroy(
 		return NB_OK;
 
 	ple = nb_running_get_entry(args->dnode, NULL, true);
+
+	/* Start prefix entry update procedure. */
+	prefix_list_entry_update_start(ple);
+
 	ple->ge = 0;
 
+	/* Finish prefix entry update procedure. */
+	prefix_list_entry_update_finish(ple);
+
 	return NB_OK;
 }
 
@@ -959,8 +998,15 @@ static int lib_prefix_list_entry_ipv4_prefix_length_lesser_or_equal_modify(
 		return NB_OK;
 
 	ple = nb_running_get_entry(args->dnode, NULL, true);
+
+	/* Start prefix entry update procedure. */
+	prefix_list_entry_update_start(ple);
+
 	ple->le = yang_dnode_get_uint8(args->dnode, NULL);
 
+	/* Finish prefix entry update procedure. */
+	prefix_list_entry_update_finish(ple);
+
 	return NB_OK;
 }
 
@@ -973,8 +1019,15 @@ static int lib_prefix_list_entry_ipv4_prefix_length_lesser_or_equal_destroy(
 		return NB_OK;
 
 	ple = nb_running_get_entry(args->dnode, NULL, true);
+
+	/* Start prefix entry update procedure. */
+	prefix_list_entry_update_start(ple);
+
 	ple->le = 0;
 
+	/* Finish prefix entry update procedure. */
+	prefix_list_entry_update_finish(ple);
+
 	return NB_OK;
 }
 
@@ -1038,9 +1091,16 @@ static int lib_prefix_list_entry_any_create(struct nb_cb_create_args *args)
 		return NB_OK;
 
 	ple = nb_running_get_entry(args->dnode, NULL, true);
+
+	/* Start prefix entry update procedure. */
+	prefix_list_entry_update_start(ple);
+
 	memset(&ple->prefix, 0, sizeof(ple->prefix));
 	ple->any = 1;
 
+	/* Finish prefix entry update procedure. */
+	prefix_list_entry_update_finish(ple);
+
 	return NB_OK;
 }
 
@@ -1052,9 +1112,16 @@ static int lib_prefix_list_entry_any_destroy(struct nb_cb_destroy_args *args)
 		return NB_OK;
 
 	ple = nb_running_get_entry(args->dnode, NULL, true);
+
+	/* Start prefix entry update procedure. */
+	prefix_list_entry_update_start(ple);
+
 	memset(&ple->prefix, 0, sizeof(ple->prefix));
 	ple->any = 1;
 
+	/* Finish prefix entry update procedure. */
+	prefix_list_entry_update_finish(ple);
+
 	return NB_OK;
 }
 

lib/plist.c

@@ -187,7 +187,7 @@ struct prefix_list_entry *prefix_list_entry_new(void)
 	return new;
 }
 
-static void prefix_list_entry_free(struct prefix_list_entry *pentry)
+void prefix_list_entry_free(struct prefix_list_entry *pentry)
 {
 	XFREE(MTYPE_PREFIX_LIST_ENTRY, pentry);
 }
@@ -646,6 +646,58 @@ static void prefix_list_entry_add(struct prefix_list *plist,
 	plist->master->recent = plist;
 }
 
+/**
+ * Prefix list entry update start procedure:
+ * Remove entry from previosly installed tries and notify observers..
+ *
+ * \param[in] ple prefix list entry.
+ */
+void prefix_list_entry_update_start(struct prefix_list_entry *ple)
+{
+	struct prefix_list *pl = ple->pl;
+
+	/* Not installed, nothing to do. */
+	if (!ple->installed)
+		return;
+
+	prefix_list_trie_del(pl, ple);
+	route_map_notify_pentry_dependencies(pl->name, ple,
+					     RMAP_EVENT_PLIST_DELETED);
+	pl->count--;
+
+	ple->installed = false;
+}
+
+/**
+ * Prefix list entry update finish procedure:
+ * Add entry back to trie, notify observers and call master hook.
+ *
+ * \param[in] ple prefix list entry.
+ */
+void prefix_list_entry_update_finish(struct prefix_list_entry *ple)
+{
+	struct prefix_list *pl = ple->pl;
+
+	/* Already installed, nothing to do. */
+	if (ple->installed)
+		return;
+
+	prefix_list_trie_add(pl, ple);
+	pl->count++;
+
+	route_map_notify_pentry_dependencies(pl->name, ple,
+					     RMAP_EVENT_PLIST_ADDED);
+
+	/* Run hook function. */
+	if (pl->master->add_hook)
+		(*pl->master->add_hook)(pl);
+
+	route_map_notify_dependencies(pl->name, RMAP_EVENT_PLIST_ADDED);
+	pl->master->recent = pl;
+
+	ple->installed = true;
+}
+
 /* Return string of prefix_list_type. */
 static const char *prefix_list_type_str(struct prefix_list_entry *pentry)
 {

lib/plist_int.h

@@ -72,8 +72,15 @@ struct prefix_list_entry {
 
 	/* up the chain for best match search */
 	struct prefix_list_entry *next_best;
+
+	/* Flag to track trie/list installation status. */
+	bool installed;
 };
 
+extern void prefix_list_entry_free(struct prefix_list_entry *pentry);
+extern void prefix_list_entry_update_start(struct prefix_list_entry *ple);
+extern void prefix_list_entry_update_finish(struct prefix_list_entry *ple);
+
 #ifdef __cplusplus
 }
 #endif