Merge pull request #7384 from opensourcerouting/nb-dyn-modules

lib: add API to load YANG modules on demand

lib/northbound.c

@@ -152,20 +152,22 @@ static int nb_node_del_cb(const struct lys_node *snode, void *arg)
 	struct nb_node *nb_node;
 
 	nb_node = snode->priv;
+	if (nb_node) {
 		lys_set_private(snode, NULL);
 		XFREE(MTYPE_NB_NODE, nb_node);
+	}
 
 	return YANG_ITER_CONTINUE;
 }
 
 void nb_nodes_create(void)
 {
-	yang_snodes_iterate_all(nb_node_new_cb, 0, NULL);
+	yang_snodes_iterate(NULL, nb_node_new_cb, 0, NULL);
 }
 
 void nb_nodes_delete(void)
 {
-	yang_snodes_iterate_all(nb_node_del_cb, 0, NULL);
+	yang_snodes_iterate(NULL, nb_node_del_cb, 0, NULL);
 }
 
 struct nb_node *nb_node_find(const char *xpath)
@@ -273,8 +275,10 @@ static int nb_node_validate(const struct lys_node *snode, void *arg)
 	unsigned int *errors = arg;
 
 	/* Validate callbacks and priority. */
+	if (nb_node) {
 		*errors += nb_node_validate_cbs(nb_node);
 		*errors += nb_node_validate_priority(nb_node);
+	}
 
 	return YANG_ITER_CONTINUE;
 }
@@ -2232,25 +2236,11 @@ static void nb_load_callbacks(const struct frr_yang_module_info *module)
 	}
 }
 
-void nb_init(struct thread_master *tm,
-	     const struct frr_yang_module_info *const modules[],
-	     size_t nmodules, bool db_enabled)
+void nb_validate_callbacks(void)
 {
 	unsigned int errors = 0;
 
-	/* Load YANG modules. */
-	for (size_t i = 0; i < nmodules; i++)
-		yang_module_load(modules[i]->name);
-
-	/* Create a nb_node for all YANG schema nodes. */
-	nb_nodes_create();
-
-	/* Load northbound callbacks. */
-	for (size_t i = 0; i < nmodules; i++)
-		nb_load_callbacks(modules[i]);
-
-	/* Validate northbound callbacks. */
-	yang_snodes_iterate_all(nb_node_validate, 0, &errors);
+	yang_snodes_iterate(NULL, nb_node_validate, 0, &errors);
 	if (errors > 0) {
 		flog_err(
 			EC_LIB_NB_CBS_VALIDATION,
@@ -2258,9 +2248,33 @@ void nb_init(struct thread_master *tm,
 			__func__, errors);
 		exit(1);
 	}
+}
 
+void nb_load_module(const struct frr_yang_module_info *module_info)
+{
+	struct yang_module *module;
+
+	DEBUGD(&nb_dbg_events, "northbound: loading %s.yang",
+	       module_info->name);
+
+	module = yang_module_load(module_info->name);
+	yang_snodes_iterate(module->info, nb_node_new_cb, 0, NULL);
+	nb_load_callbacks(module_info);
+}
+
+void nb_init(struct thread_master *tm,
+	     const struct frr_yang_module_info *const modules[],
+	     size_t nmodules, bool db_enabled)
+{
 	nb_db_enabled = db_enabled;
 
+	/* Load YANG modules and their corresponding northbound callbacks. */
+	for (size_t i = 0; i < nmodules; i++)
+		nb_load_module(modules[i]);
+
+	/* Validate northbound callbacks. */
+	nb_validate_callbacks();
+
 	/* Create an empty running configuration. */
 	running_config = nb_config_new(NULL);
 	running_config_entries = hash_create(running_config_entry_key_make,

lib/northbound.h

@@ -1237,6 +1237,29 @@ extern const char *nb_err_name(enum nb_error error);
  */
 extern const char *nb_client_name(enum nb_client client);
 
+/*
+ * Validate all northbound callbacks.
+ *
+ * Some errors, like missing callbacks or invalid priorities, are fatal and
+ * can't be recovered from. Other errors, like unneeded callbacks, are logged
+ * but otherwise ignored.
+ *
+ * Whenever a YANG module is loaded after startup, *all* northbound callbacks
+ * need to be validated and not only the callbacks from the newly loaded module.
+ * This is because augmentations can change the properties of the augmented
+ * module, making mandatory the implementation of additional callbacks.
+ */
+void nb_validate_callbacks(void);
+
+/*
+ * Load a YANG module with its corresponding northbound callbacks.
+ *
+ * module_info
+ *    Pointer to structure containing the module name and its northbound
+ *    callbacks.
+ */
+void nb_load_module(const struct frr_yang_module_info *module_info);
+
 /*
  * Initialize the northbound layer. Should be called only once during the
  * daemon initialization process.

lib/northbound_confd.c

@@ -550,6 +550,9 @@ static int frr_confd_init_cdb(void)
 				continue;
 
 			nb_node = snode->priv;
+			if (!nb_node)
+				continue;
+
 			DEBUGD(&nb_dbg_client_confd, "%s: subscribing to '%s'",
 			       __func__, nb_node->xpath);
 
@@ -1189,7 +1192,7 @@ static int frr_confd_subscribe_state(const struct lys_node *snode, void *arg)
 	struct nb_node *nb_node = snode->priv;
 	struct confd_data_cbs *data_cbs = arg;
 
-	if (!CHECK_FLAG(snode->flags, LYS_CONFIG_R))
+	if (!nb_node || !CHECK_FLAG(snode->flags, LYS_CONFIG_R))
 		return YANG_ITER_CONTINUE;
 	/* We only need to subscribe to the root of the state subtrees. */
 	if (snode->parent && CHECK_FLAG(snode->parent->flags, LYS_CONFIG_R))
@@ -1276,7 +1279,7 @@ static int frr_confd_init_dp(const char *program_name)
 	 * Iterate over all loaded YANG modules and subscribe to the paths
 	 * referent to state data.
 	 */
-	yang_snodes_iterate_all(frr_confd_subscribe_state, 0, &data_cbs);
+	yang_snodes_iterate(NULL, frr_confd_subscribe_state, 0, &data_cbs);
 
 	/* Register notification stream. */
 	memset(&ncbs, 0, sizeof(ncbs));
@@ -1393,6 +1396,7 @@ static int frr_confd_calculate_snode_hash(const struct lys_node *snode,
 {
 	struct nb_node *nb_node = snode->priv;
 
+	if (nb_node)
 		nb_node->confd_hash = confd_str2hash(snode->name);
 
 	return YANG_ITER_CONTINUE;
@@ -1426,7 +1430,7 @@ static int frr_confd_init(const char *program_name)
 		goto error;
 	}
 
-	yang_snodes_iterate_all(frr_confd_calculate_snode_hash, 0, NULL);
+	yang_snodes_iterate(NULL, frr_confd_calculate_snode_hash, 0, NULL);
 
 	hook_register(nb_notification_send, frr_confd_notification_send);
 

lib/northbound_sysrepo.c

@@ -575,6 +575,8 @@ static int frr_sr_subscribe_state(const struct lys_node *snode, void *arg)
 		return YANG_ITER_CONTINUE;
 
 	nb_node = snode->priv;
+	if (!nb_node)
+		return YANG_ITER_CONTINUE;
 
 	DEBUGD(&nb_dbg_client_sysrepo, "sysrepo: providing data to '%s'",
 	       nb_node->xpath);
@@ -599,6 +601,8 @@ static int frr_sr_subscribe_rpc(const struct lys_node *snode, void *arg)
 		return YANG_ITER_CONTINUE;
 
 	nb_node = snode->priv;
+	if (!nb_node)
+		return YANG_ITER_CONTINUE;
 
 	DEBUGD(&nb_dbg_client_sysrepo, "sysrepo: providing RPC to '%s'",
 	       nb_node->xpath);
@@ -686,10 +690,10 @@ static int frr_sr_init(void)
 		int event_pipe;
 
 		frr_sr_subscribe_config(module);
-		yang_snodes_iterate_module(module->info, frr_sr_subscribe_state,
-					   0, module);
-		yang_snodes_iterate_module(module->info, frr_sr_subscribe_rpc,
-					   0, module);
+		yang_snodes_iterate(module->info, frr_sr_subscribe_state, 0,
+				    module);
+		yang_snodes_iterate(module->info, frr_sr_subscribe_rpc, 0,
+				    module);
 
 		/* Watch subscriptions. */
 		ret = sr_get_event_pipe(module->sr_subscription, &event_pipe);

lib/yang.c

@@ -227,40 +227,22 @@ next:
 	return ret;
 }
 
-int yang_snodes_iterate_module(const struct lys_module *module,
-			       yang_iterate_cb cb, uint16_t flags, void *arg)
+int yang_snodes_iterate(const struct lys_module *module, yang_iterate_cb cb,
+			uint16_t flags, void *arg)
 {
-	struct lys_node *snode;
+	const struct lys_module *module_iter;
+	uint32_t idx = 0;
 	int ret = YANG_ITER_CONTINUE;
 
-	LY_TREE_FOR (module->data, snode) {
-		ret = yang_snodes_iterate_subtree(snode, module, cb, flags,
-						  arg);
-		if (ret == YANG_ITER_STOP)
-			return ret;
-	}
-
-	for (uint8_t i = 0; i < module->augment_size; i++) {
-		ret = yang_snodes_iterate_subtree(
-			(const struct lys_node *)&module->augment[i], module,
-			cb, flags, arg);
-		if (ret == YANG_ITER_STOP)
-			return ret;
-	}
-
-	return ret;
-}
-
-int yang_snodes_iterate_all(yang_iterate_cb cb, uint16_t flags, void *arg)
-{
-	struct yang_module *module;
-	int ret = YANG_ITER_CONTINUE;
-
-	RB_FOREACH (module, yang_modules, &yang_modules) {
+	idx = ly_ctx_internal_modules_count(ly_native_ctx);
+	while ((module_iter = ly_ctx_get_module_iter(ly_native_ctx, &idx))) {
 		struct lys_node *snode;
 
-		LY_TREE_FOR (module->info->data, snode) {
-			ret = yang_snodes_iterate_subtree(snode, NULL, cb,
+		if (!module_iter->implemented)
+			continue;
+
+		LY_TREE_FOR (module_iter->data, snode) {
+			ret = yang_snodes_iterate_subtree(snode, module, cb,
 							  flags, arg);
 			if (ret == YANG_ITER_STOP)
 				return ret;

lib/yang.h

@@ -186,10 +186,11 @@ extern int yang_snodes_iterate_subtree(const struct lys_node *snode,
 				       void *arg);
 
 /*
- * Iterate over all libyang schema nodes from the given YANG module.
+ * Iterate over all libyang schema nodes from all loeaded modules of from the
+ * given YANG module.
  *
  * module
- *    YANG module to operate on.
+ *    When set, iterate over all nodes of the specified module only.
  *
  * cb
  *    Function to call with each schema node.
@@ -203,27 +204,8 @@ extern int yang_snodes_iterate_subtree(const struct lys_node *snode,
  * Returns:
  *    The return value of the last called callback.
  */
-extern int yang_snodes_iterate_module(const struct lys_module *module,
-				      yang_iterate_cb cb, uint16_t flags,
-				      void *arg);
-
-/*
- * Iterate over all libyang schema nodes from all loaded YANG modules.
- *
- * cb
- *    Function to call with each schema node.
- *
- * flags
- *    YANG_ITER_* flags to control how the iteration is performed.
- *
- * arg
- *    Arbitrary argument passed as the second parameter in each call to 'cb'.
- *
- * Returns:
- *    The return value of the last called callback.
- */
-extern int yang_snodes_iterate_all(yang_iterate_cb cb, uint16_t flags,
-				   void *arg);
+extern int yang_snodes_iterate(const struct lys_module *module,
+			       yang_iterate_cb cb, uint16_t flags, void *arg);
 
 /*
  * Build schema path or data path of the schema node.

lib/yang_translator.c

@@ -469,8 +469,8 @@ static unsigned int yang_translator_validate(struct yang_translator *translator)
 	args.errors = 0;
 
 	for (ALL_LIST_ELEMENTS_RO(translator->modules, ln, tmodule)) {
-		yang_snodes_iterate_module(
-			tmodule->module, yang_translator_validate_cb,
+		yang_snodes_iterate(tmodule->module,
+				    yang_translator_validate_cb,
 				    YANG_ITER_FILTER_NPCONTAINERS
 					    | YANG_ITER_FILTER_LIST_KEYS
 					    | YANG_ITER_FILTER_INPUT_OUTPUT,
@@ -500,7 +500,7 @@ static unsigned int yang_module_nodes_count(const struct lys_module *module)
 {
 	unsigned int total = 0;
 
-	yang_snodes_iterate_module(module, yang_module_nodes_count_cb,
+	yang_snodes_iterate(module, yang_module_nodes_count_cb,
 			    YANG_ITER_FILTER_NPCONTAINERS
 				    | YANG_ITER_FILTER_LIST_KEYS
 				    | YANG_ITER_FILTER_INPUT_OUTPUT,

tools/gen_northbound_callbacks.c

@@ -368,13 +368,12 @@ int main(int argc, char *argv[])
 	/* Generate callback prototypes. */
 	if (!static_cbs) {
 		printf("/* prototypes */\n");
-		yang_snodes_iterate_module(module->info, generate_prototypes, 0,
-					   NULL);
+		yang_snodes_iterate(module->info, generate_prototypes, 0, NULL);
 		printf("\n");
 	}
 
 	/* Generate callback functions. */
-	yang_snodes_iterate_module(module->info, generate_callbacks, 0, NULL);
+	yang_snodes_iterate(module->info, generate_callbacks, 0, NULL);
 
 	strlcpy(module_name_underscores, module->name,
 		sizeof(module_name_underscores));
@@ -386,7 +385,7 @@ int main(int argc, char *argv[])
 	       "\t.name = \"%s\",\n"
 	       "\t.nodes = {\n",
 	       module_name_underscores, module->name);
-	yang_snodes_iterate_module(module->info, generate_nb_nodes, 0, NULL);
+	yang_snodes_iterate(module->info, generate_nb_nodes, 0, NULL);
 	printf("\t\t{\n"
 	       "\t\t\t.xpath = NULL,\n"
 	       "\t\t},\n");

tools/gen_yang_deviations.c

@@ -71,7 +71,7 @@ int main(int argc, char *argv[])
 	module = yang_module_load(argv[0]);
 
 	/* Generate deviations. */
-	yang_snodes_iterate_module(module->info, generate_yang_deviation,
+	yang_snodes_iterate(module->info, generate_yang_deviation,
 			    YANG_ITER_FILTER_IMPLICIT, NULL);
 
 	/* Cleanup and exit. */