lib: fix iteration over schema nodes of a single YANG module

The only safe way to iterate over all schema nodes of a given YANG
module is by iterating over all schema nodes of all YANG modules
and filter out the nodes that belong to other modules.

The original yang_snodes_iterate_module() code did the following:
1 - Iterate over all top-level schema nodes of the given module;
2 - Iterate over all augmentations of the given module.

While that iteration strategy is more efficient, it does't handle
well more complex YANG hierarchies containing nested augmentations
or self-augmenting modules. Any iteration that isn't done on the
resolved YANG data hierarchy is fragile and prone to errors.

Fixes regression introduced by commit 8a923b48513316b where the
gen_northbound_callbacks tool was generating duplicate callbacks
for certain modules.

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

1 files changed, 6 insertions, 2 deletions

diff --git a/lib/northbound_confd.c b/lib/northbound_confd.c
index c1cb0fc11..a53e90d55 100644
--- a/lib/northbound_confd.c
+++ b/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))
@@ -1393,7 +1396,8 @@ static int frr_confd_calculate_snode_hash(const struct lys_node *snode,
 {
 	struct nb_node *nb_node = snode->priv;
 
-	nb_node->confd_hash = confd_str2hash(snode->name);
+	if (nb_node)
+		nb_node->confd_hash = confd_str2hash(snode->name);
 
 	return YANG_ITER_CONTINUE;
 }