lib: add support for YANG lists with mixed config and state data

A YANG list that contains both configuration and state data must have
the following callbacks: create(), delete(), get_next(), get_keys()
and lookup_entry().

Signed-off-by: Renato Westphal <renato@opensourcerouting.org>

lib/northbound.c

@@ -51,6 +51,18 @@ static int nb_transaction_process(enum nb_event event,
 				  struct nb_transaction *transaction);
 static void nb_transaction_apply_finish(struct nb_transaction *transaction);
 
+static int nb_node_check_config_only(const struct lys_node *snode, void *arg)
+{
+	bool *config_only = arg;
+
+	if (CHECK_FLAG(snode->flags, LYS_CONFIG_R)) {
+		*config_only = false;
+		return YANG_ITER_STOP;
+	}
+
+	return YANG_ITER_CONTINUE;
+}
+
 static int nb_node_new_cb(const struct lys_node *snode, void *arg)
 {
 	struct nb_node *nb_node;
@@ -67,6 +79,17 @@ static int nb_node_new_cb(const struct lys_node *snode, void *arg)
 	if (sparent_list)
 		nb_node->parent_list = sparent_list->priv;
 
+	/* Set flags. */
+	if (CHECK_FLAG(snode->nodetype, LYS_CONTAINER | LYS_LIST)) {
+		bool config_only = true;
+
+		yang_snodes_iterate_subtree(snode, nb_node_check_config_only,
+					    YANG_ITER_ALLOW_AUGMENTATIONS,
+					    &config_only);
+		if (config_only)
+			SET_FLAG(nb_node->flags, F_NB_NODE_CONFIG_ONLY);
+	}
+
 	/*
 	 * Link the northbound node and the libyang schema node with one
 	 * another.
@@ -88,6 +111,16 @@ static int nb_node_del_cb(const struct lys_node *snode, void *arg)
 	return YANG_ITER_CONTINUE;
 }
 
+void nb_nodes_create(void)
+{
+	yang_snodes_iterate_all(nb_node_new_cb, 0, NULL);
+}
+
+void nb_nodes_delete(void)
+{
+	yang_snodes_iterate_all(nb_node_del_cb, 0, NULL);
+}
+
 struct nb_node *nb_node_find(const char *xpath)
 {
 	const struct lys_node *snode;
@@ -900,6 +933,7 @@ static void nb_transaction_apply_finish(struct nb_transaction *transaction)
 bool nb_operation_is_valid(enum nb_operation operation,
 			   const struct lys_node *snode)
 {
+	struct nb_node *nb_node = snode->priv;
 	struct lys_node_container *scontainer;
 	struct lys_node_leaf *sleaf;
 
@@ -1017,11 +1051,10 @@ bool nb_operation_is_valid(enum nb_operation operation,
 	case NB_OP_GET_NEXT:
 	case NB_OP_GET_KEYS:
 	case NB_OP_LOOKUP_ENTRY:
-		if (!CHECK_FLAG(snode->flags, LYS_CONFIG_R))
-			return false;
-
 		switch (snode->nodetype) {
 		case LYS_LIST:
+			if (CHECK_FLAG(nb_node->flags, F_NB_NODE_CONFIG_ONLY))
+				return false;
 			break;
 		default:
 			return false;
@@ -1170,7 +1203,7 @@ void nb_init(const struct frr_yang_module_info *modules[], size_t nmodules)
 		yang_module_load(modules[i]->name);
 
 	/* Create a nb_node for all YANG schema nodes. */
-	yang_snodes_iterate_all(nb_node_new_cb, 0, NULL);
+	nb_nodes_create();
 
 	/* Load northbound callbacks. */
 	for (size_t i = 0; i < nmodules; i++)
@@ -1205,7 +1238,7 @@ void nb_terminate(void)
 	nb_cli_terminate();
 
 	/* Delete all nb_node's from all YANG modules. */
-	yang_snodes_iterate_all(nb_node_del_cb, 0, NULL);
+	nb_nodes_delete();
 
 	/* Delete the running configuration. */
 	nb_config_free(running_config);

lib/northbound.h

@@ -349,11 +349,16 @@ struct nb_node {
 	/* Pointer to the nearest parent list, if any. */
 	struct nb_node *parent_list;
 
+	/* Flags. */
+	uint8_t flags;
+
 #ifdef HAVE_CONFD
 	/* ConfD hash value corresponding to this YANG path. */
 	int confd_hash;
 #endif
 };
+/* The YANG container or list contains only config data. */
+#define F_NB_NODE_CONFIG_ONLY 0x01
 
 struct frr_yang_module_info {
 	/* YANG module name. */
@@ -435,6 +440,16 @@ DECLARE_HOOK(nb_notification_send, (const char *xpath, struct list *arguments),
 extern int debug_northbound;
 extern struct nb_config *running_config;
 
+/*
+ * Create a northbound node for all YANG schema nodes.
+ */
+void nb_nodes_create(void);
+
+/*
+ * Delete all northbound nodes from all YANG schema nodes.
+ */
+void nb_nodes_delete(void);
+
 /*
  * Find the northbound node corresponding to a YANG data path.
  *

lib/yang.c

@@ -195,7 +195,8 @@ next:
 		return YANG_ITER_CONTINUE;
 
 	LY_TREE_FOR (snode->child, child) {
-		if (child->parent != snode)
+		if (!CHECK_FLAG(flags, YANG_ITER_ALLOW_AUGMENTATIONS)
+		    && child->parent != snode)
 			continue;
 
 		ret = yang_snodes_iterate_subtree(child, cb, flags, arg);

lib/yang.h

@@ -98,6 +98,9 @@ enum yang_iter_flags {
 
 	/* Filter implicitely created nodes. */
 	YANG_ITER_FILTER_IMPLICIT = (1<<3),
+
+	/* Allow iteration over augmentations. */
+	YANG_ITER_ALLOW_AUGMENTATIONS = (1<<4),
 };
 
 /* Callback used by the yang_snodes_iterate_*() family of functions. */

tools/gen_northbound_callbacks.c

@@ -272,8 +272,15 @@ int main(int argc, char *argv[])
 
 	yang_init();
 
-	/* Load YANG module. */
-	module = yang_module_load(argv[0]);
+	/* Load all FRR native models to ensure all augmentations are loaded. */
+	yang_module_load_all();
+	module = yang_module_find(argv[0]);
+	if (!module)
+		/* Non-native FRR module (e.g. modules from unit tests). */
+		module = yang_module_load(argv[0]);
+
+	/* Create a nb_node for all YANG schema nodes. */
+	nb_nodes_create();
 
 	/* Generate callback functions. */
 	yang_snodes_iterate_module(module->info, generate_callbacks, 0, NULL);
@@ -296,6 +303,7 @@ int main(int argc, char *argv[])
 	       "};\n");
 
 	/* Cleanup and exit. */
+	nb_nodes_delete();
 	yang_terminate();
 
 	return 0;