bfdd: split northbound callbacks into multiple files

Rearrange the bfdd northbound callbacks as following:
* bfd_nb.h: prototypes of all northbound callbacks.
* bfd_nb.c: definition of all northbound callbacks and their
  associated YANG data paths.
* bfd_nb_config.c: implementation of YANG configuration nodes.
* bfd_nb_state.c: implementation of YANG state nodes.

This should help to keep to code more organized and easier to
maintain.

No behavior changes intended.

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

9 files changed, 1514 insertions, 1268 deletions

diff --git a/bfdd/bfd.h b/bfdd/bfd.h
index 815b0aec2..220dd6e0a 100644
--- a/bfdd/bfd.h
+++ b/bfdd/bfd.h
@@ -593,29 +593,6 @@ void bfdd_vty_init(void);
  */
 void bfdd_cli_init(void);
 
-void bfd_cli_show_header(struct vty *vty, struct lyd_node *dnode,
-			 bool show_defaults);
-void bfd_cli_show_header_end(struct vty *vty, struct lyd_node *dnode);
-void bfd_cli_show_single_hop_peer(struct vty *vty,
-				  struct lyd_node *dnode,
-				  bool show_defaults);
-void bfd_cli_show_multi_hop_peer(struct vty *vty,
-				 struct lyd_node *dnode,
-				 bool show_defaults);
-void bfd_cli_show_peer_end(struct vty *vty, struct lyd_node *dnode);
-void bfd_cli_show_mult(struct vty *vty, struct lyd_node *dnode,
-		       bool show_defaults);
-void bfd_cli_show_tx(struct vty *vty, struct lyd_node *dnode,
-		     bool show_defaults);
-void bfd_cli_show_rx(struct vty *vty, struct lyd_node *dnode,
-		     bool show_defaults);
-void bfd_cli_show_shutdown(struct vty *vty, struct lyd_node *dnode,
-			   bool show_defaults);
-void bfd_cli_show_echo(struct vty *vty, struct lyd_node *dnode,
-			   bool show_defaults);
-void bfd_cli_show_echo_interval(struct vty *vty, struct lyd_node *dnode,
-				bool show_defaults);
-
 
 /*
  * ptm_adapter.c
@@ -630,12 +607,4 @@ void bfd_session_update_vrf_name(struct bfd_session *bs, struct vrf *vrf);
 
 int ptm_bfd_notify(struct bfd_session *bs, uint8_t notify_state);
 
-
-/*
- * bfdd_northbound.c
- *
- * BFD northbound callbacks.
- */
-extern const struct frr_yang_module_info frr_bfdd_info;
-
 #endif /* _BFD_H_ */
diff --git a/bfdd/bfdd.c b/bfdd/bfdd.c
index 5657744f7..a91fa3d04 100644
--- a/bfdd/bfdd.c
+++ b/bfdd/bfdd.c
@@ -23,6 +23,7 @@
 #include "filter.h"
 
 #include "bfd.h"
+#include "bfdd_nb.h"
 #include "lib/version.h"
 
 
diff --git a/bfdd/bfdd_cli.c b/bfdd/bfdd_cli.c
index acb1801cc..3e44fcb22 100644
--- a/bfdd/bfdd_cli.c
+++ b/bfdd/bfdd_cli.c
@@ -31,6 +31,7 @@
 #endif /* VTYSH_EXTRACT_PL */
 
 #include "bfd.h"
+#include "bfdd_nb.h"
 
 /*
  * Definitions.
diff --git a/bfdd/bfdd_nb.c b/bfdd/bfdd_nb.c
new file mode 100644
index 000000000..8d4674233
--- /dev/null
+++ b/bfdd/bfdd_nb.c
@@ -0,0 +1,388 @@
+/*
+ * BFD daemon northbound implementation.
+ *
+ * Copyright (C) 2019 Network Device Education Foundation, Inc. ("NetDEF")
+ *                    Rafael Zalamena
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301 USA.
+ */
+
+#include <zebra.h>
+
+#include "lib/log.h"
+#include "lib/northbound.h"
+
+#include "bfdd_nb.h"
+
+/* clang-format off */
+const struct frr_yang_module_info frr_bfdd_info = {
+	.name = "frr-bfdd",
+	.nodes = {
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd",
+			.cbs = {
+				.create = bfdd_bfd_create,
+				.destroy = bfdd_bfd_destroy,
+				.cli_show = bfd_cli_show_header,
+				.cli_show_end = bfd_cli_show_header_end,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop",
+			.cbs = {
+				.create = bfdd_bfd_sessions_single_hop_create,
+				.destroy = bfdd_bfd_sessions_single_hop_destroy,
+				.get_next = bfdd_bfd_sessions_single_hop_get_next,
+				.get_keys = bfdd_bfd_sessions_single_hop_get_keys,
+				.lookup_entry = bfdd_bfd_sessions_single_hop_lookup_entry,
+				.cli_show = bfd_cli_show_single_hop_peer,
+				.cli_show_end = bfd_cli_show_peer_end,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/source-addr",
+			.cbs = {
+				.modify = bfdd_bfd_sessions_single_hop_source_addr_modify,
+				.destroy = bfdd_bfd_sessions_single_hop_source_addr_destroy,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/detection-multiplier",
+			.cbs = {
+				.modify = bfdd_bfd_sessions_single_hop_detection_multiplier_modify,
+				.cli_show = bfd_cli_show_mult,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/desired-transmission-interval",
+			.cbs = {
+				.modify = bfdd_bfd_sessions_single_hop_desired_transmission_interval_modify,
+				.cli_show = bfd_cli_show_tx,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/required-receive-interval",
+			.cbs = {
+				.modify = bfdd_bfd_sessions_single_hop_required_receive_interval_modify,
+				.cli_show = bfd_cli_show_rx,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/administrative-down",
+			.cbs = {
+				.modify = bfdd_bfd_sessions_single_hop_administrative_down_modify,
+				.cli_show = bfd_cli_show_shutdown,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/echo-mode",
+			.cbs = {
+				.modify = bfdd_bfd_sessions_single_hop_echo_mode_modify,
+				.cli_show = bfd_cli_show_echo,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/desired-echo-transmission-interval",
+			.cbs = {
+				.modify = bfdd_bfd_sessions_single_hop_desired_echo_transmission_interval_modify,
+				.cli_show = bfd_cli_show_echo_interval,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/local-discriminator",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_local_discriminator_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/local-state",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_local_state_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/local-diagnostic",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_local_diagnostic_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/local-multiplier",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_local_multiplier_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/remote-discriminator",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_remote_discriminator_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/remote-state",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_remote_state_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/remote-diagnostic",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_remote_diagnostic_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/remote-multiplier",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_remote_multiplier_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/negotiated-transmission-interval",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_negotiated_transmission_interval_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/negotiated-receive-interval",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_negotiated_receive_interval_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/detection-mode",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_detection_mode_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/last-down-time",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_last_down_time_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/last-up-time",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_last_up_time_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/session-down-count",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_session_down_count_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/session-up-count",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_session_up_count_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/control-packet-input-count",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_control_packet_input_count_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/control-packet-output-count",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_control_packet_output_count_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/negotiated-echo-transmission-interval",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_negotiated_echo_transmission_interval_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/echo-packet-input-count",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_echo_packet_input_count_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/echo-packet-output-count",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_echo_packet_output_count_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop",
+			.cbs = {
+				.create = bfdd_bfd_sessions_multi_hop_create,
+				.destroy = bfdd_bfd_sessions_multi_hop_destroy,
+				.get_next = bfdd_bfd_sessions_multi_hop_get_next,
+				.get_keys = bfdd_bfd_sessions_multi_hop_get_keys,
+				.lookup_entry = bfdd_bfd_sessions_multi_hop_lookup_entry,
+				.cli_show = bfd_cli_show_multi_hop_peer,
+				.cli_show_end = bfd_cli_show_peer_end,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/detection-multiplier",
+			.cbs = {
+				.modify = bfdd_bfd_sessions_single_hop_detection_multiplier_modify,
+				.cli_show = bfd_cli_show_mult,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/desired-transmission-interval",
+			.cbs = {
+				.modify = bfdd_bfd_sessions_single_hop_desired_transmission_interval_modify,
+				.cli_show = bfd_cli_show_tx,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/required-receive-interval",
+			.cbs = {
+				.modify = bfdd_bfd_sessions_single_hop_required_receive_interval_modify,
+				.cli_show = bfd_cli_show_rx,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/administrative-down",
+			.cbs = {
+				.modify = bfdd_bfd_sessions_single_hop_administrative_down_modify,
+				.cli_show = bfd_cli_show_shutdown,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/local-discriminator",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_local_discriminator_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/local-state",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_local_state_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/local-diagnostic",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_local_diagnostic_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/local-multiplier",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_local_multiplier_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/remote-discriminator",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_remote_discriminator_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/remote-state",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_remote_state_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/remote-diagnostic",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_remote_diagnostic_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/remote-multiplier",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_remote_multiplier_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/negotiated-transmission-interval",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_negotiated_transmission_interval_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/negotiated-receive-interval",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_negotiated_receive_interval_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/detection-mode",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_detection_mode_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/last-down-time",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_last_down_time_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/last-up-time",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_last_up_time_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/session-down-count",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_session_down_count_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/session-up-count",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_session_up_count_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/control-packet-input-count",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_control_packet_input_count_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/control-packet-output-count",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_control_packet_output_count_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/negotiated-echo-transmission-interval",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_negotiated_echo_transmission_interval_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/echo-packet-input-count",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_echo_packet_input_count_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/echo-packet-output-count",
+			.cbs = {
+				.get_elem = bfdd_bfd_sessions_single_hop_stats_echo_packet_output_count_get_elem,
+			}
+		},
+		{
+			.xpath = NULL,
+		},
+	}
+};
diff --git a/bfdd/bfdd_nb.h b/bfdd/bfdd_nb.h
new file mode 100644
index 000000000..8377c87bb
--- /dev/null
+++ b/bfdd/bfdd_nb.h
@@ -0,0 +1,217 @@
+/*
+ * BFD daemon northbound implementation.
+ *
+ * Copyright (C) 2019 Network Device Education Foundation, Inc. ("NetDEF")
+ *                    Rafael Zalamena
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301 USA.
+ */
+
+#ifndef _FRR_BFDD_NB_H_
+#define _FRR_BFDD_NB_H_
+
+extern const struct frr_yang_module_info frr_bfdd_info;
+
+/* Mandatory callbacks. */
+int bfdd_bfd_create(enum nb_event event, const struct lyd_node *dnode,
+		    union nb_resource *resource);
+int bfdd_bfd_destroy(enum nb_event event, const struct lyd_node *dnode);
+int bfdd_bfd_sessions_single_hop_create(enum nb_event event,
+					const struct lyd_node *dnode,
+					union nb_resource *resource);
+int bfdd_bfd_sessions_single_hop_destroy(enum nb_event event,
+					 const struct lyd_node *dnode);
+const void *bfdd_bfd_sessions_single_hop_get_next(const void *parent_list_entry,
+						  const void *list_entry);
+int bfdd_bfd_sessions_single_hop_get_keys(const void *list_entry,
+					  struct yang_list_keys *keys);
+const void *
+bfdd_bfd_sessions_single_hop_lookup_entry(const void *parent_list_entry,
+					  const struct yang_list_keys *keys);
+int bfdd_bfd_sessions_single_hop_source_addr_modify(
+	enum nb_event event, const struct lyd_node *dnode,
+	union nb_resource *resource);
+int bfdd_bfd_sessions_single_hop_source_addr_destroy(
+	enum nb_event event, const struct lyd_node *dnode);
+int bfdd_bfd_sessions_single_hop_detection_multiplier_modify(
+	enum nb_event event, const struct lyd_node *dnode,
+	union nb_resource *resource);
+int bfdd_bfd_sessions_single_hop_desired_transmission_interval_modify(
+	enum nb_event event, const struct lyd_node *dnode,
+	union nb_resource *resource);
+int bfdd_bfd_sessions_single_hop_required_receive_interval_modify(
+	enum nb_event event, const struct lyd_node *dnode,
+	union nb_resource *resource);
+int bfdd_bfd_sessions_single_hop_administrative_down_modify(
+	enum nb_event event, const struct lyd_node *dnode,
+	union nb_resource *resource);
+int bfdd_bfd_sessions_single_hop_echo_mode_modify(enum nb_event event,
+						  const struct lyd_node *dnode,
+						  union nb_resource *resource);
+int bfdd_bfd_sessions_single_hop_desired_echo_transmission_interval_modify(
+	enum nb_event event, const struct lyd_node *dnode,
+	union nb_resource *resource);
+struct yang_data *
+bfdd_bfd_sessions_single_hop_stats_local_discriminator_get_elem(
+	const char *xpath, const void *list_entry);
+struct yang_data *
+bfdd_bfd_sessions_single_hop_stats_local_state_get_elem(const char *xpath,
+							const void *list_entry);
+struct yang_data *bfdd_bfd_sessions_single_hop_stats_local_diagnostic_get_elem(
+	const char *xpath, const void *list_entry);
+struct yang_data *bfdd_bfd_sessions_single_hop_stats_local_multiplier_get_elem(
+	const char *xpath, const void *list_entry);
+struct yang_data *
+bfdd_bfd_sessions_single_hop_stats_remote_discriminator_get_elem(
+	const char *xpath, const void *list_entry);
+struct yang_data *bfdd_bfd_sessions_single_hop_stats_remote_state_get_elem(
+	const char *xpath, const void *list_entry);
+struct yang_data *bfdd_bfd_sessions_single_hop_stats_remote_diagnostic_get_elem(
+	const char *xpath, const void *list_entry);
+struct yang_data *bfdd_bfd_sessions_single_hop_stats_remote_multiplier_get_elem(
+	const char *xpath, const void *list_entry);
+struct yang_data *
+bfdd_bfd_sessions_single_hop_stats_negotiated_transmission_interval_get_elem(
+	const char *xpath, const void *list_entry);
+struct yang_data *
+bfdd_bfd_sessions_single_hop_stats_negotiated_receive_interval_get_elem(
+	const char *xpath, const void *list_entry);
+struct yang_data *bfdd_bfd_sessions_single_hop_stats_detection_mode_get_elem(
+	const char *xpath, const void *list_entry);
+struct yang_data *bfdd_bfd_sessions_single_hop_stats_last_down_time_get_elem(
+	const char *xpath, const void *list_entry);
+struct yang_data *bfdd_bfd_sessions_single_hop_stats_last_up_time_get_elem(
+	const char *xpath, const void *list_entry);
+struct yang_data *
+bfdd_bfd_sessions_single_hop_stats_session_down_count_get_elem(
+	const char *xpath, const void *list_entry);
+struct yang_data *bfdd_bfd_sessions_single_hop_stats_session_up_count_get_elem(
+	const char *xpath, const void *list_entry);
+struct yang_data *
+bfdd_bfd_sessions_single_hop_stats_control_packet_input_count_get_elem(
+	const char *xpath, const void *list_entry);
+struct yang_data *
+bfdd_bfd_sessions_single_hop_stats_control_packet_output_count_get_elem(
+	const char *xpath, const void *list_entry);
+struct yang_data *
+bfdd_bfd_sessions_single_hop_stats_negotiated_echo_transmission_interval_get_elem(
+	const char *xpath, const void *list_entry);
+struct yang_data *
+bfdd_bfd_sessions_single_hop_stats_echo_packet_input_count_get_elem(
+	const char *xpath, const void *list_entry);
+struct yang_data *
+bfdd_bfd_sessions_single_hop_stats_echo_packet_output_count_get_elem(
+	const char *xpath, const void *list_entry);
+int bfdd_bfd_sessions_multi_hop_create(enum nb_event event,
+				       const struct lyd_node *dnode,
+				       union nb_resource *resource);
+int bfdd_bfd_sessions_multi_hop_destroy(enum nb_event event,
+					const struct lyd_node *dnode);
+const void *bfdd_bfd_sessions_multi_hop_get_next(const void *parent_list_entry,
+						 const void *list_entry);
+int bfdd_bfd_sessions_multi_hop_get_keys(const void *list_entry,
+					 struct yang_list_keys *keys);
+const void *
+bfdd_bfd_sessions_multi_hop_lookup_entry(const void *parent_list_entry,
+					 const struct yang_list_keys *keys);
+int bfdd_bfd_sessions_multi_hop_detection_multiplier_modify(
+	enum nb_event event, const struct lyd_node *dnode,
+	union nb_resource *resource);
+int bfdd_bfd_sessions_multi_hop_desired_transmission_interval_modify(
+	enum nb_event event, const struct lyd_node *dnode,
+	union nb_resource *resource);
+int bfdd_bfd_sessions_multi_hop_required_receive_interval_modify(
+	enum nb_event event, const struct lyd_node *dnode,
+	union nb_resource *resource);
+int bfdd_bfd_sessions_multi_hop_administrative_down_modify(
+	enum nb_event event, const struct lyd_node *dnode,
+	union nb_resource *resource);
+struct yang_data *
+bfdd_bfd_sessions_multi_hop_stats_local_discriminator_get_elem(
+	const char *xpath, const void *list_entry);
+struct yang_data *
+bfdd_bfd_sessions_multi_hop_stats_local_state_get_elem(const char *xpath,
+						       const void *list_entry);
+struct yang_data *bfdd_bfd_sessions_multi_hop_stats_local_diagnostic_get_elem(
+	const char *xpath, const void *list_entry);
+struct yang_data *bfdd_bfd_sessions_multi_hop_stats_local_multiplier_get_elem(
+	const char *xpath, const void *list_entry);
+struct yang_data *
+bfdd_bfd_sessions_multi_hop_stats_remote_discriminator_get_elem(
+	const char *xpath, const void *list_entry);
+struct yang_data *
+bfdd_bfd_sessions_multi_hop_stats_remote_state_get_elem(const char *xpath,
+							const void *list_entry);
+struct yang_data *bfdd_bfd_sessions_multi_hop_stats_remote_diagnostic_get_elem(
+	const char *xpath, const void *list_entry);
+struct yang_data *bfdd_bfd_sessions_multi_hop_stats_remote_multiplier_get_elem(
+	const char *xpath, const void *list_entry);
+struct yang_data *
+bfdd_bfd_sessions_multi_hop_stats_negotiated_transmission_interval_get_elem(
+	const char *xpath, const void *list_entry);
+struct yang_data *
+bfdd_bfd_sessions_multi_hop_stats_negotiated_receive_interval_get_elem(
+	const char *xpath, const void *list_entry);
+struct yang_data *bfdd_bfd_sessions_multi_hop_stats_detection_mode_get_elem(
+	const char *xpath, const void *list_entry);
+struct yang_data *bfdd_bfd_sessions_multi_hop_stats_last_down_time_get_elem(
+	const char *xpath, const void *list_entry);
+struct yang_data *
+bfdd_bfd_sessions_multi_hop_stats_last_up_time_get_elem(const char *xpath,
+							const void *list_entry);
+struct yang_data *bfdd_bfd_sessions_multi_hop_stats_session_down_count_get_elem(
+	const char *xpath, const void *list_entry);
+struct yang_data *bfdd_bfd_sessions_multi_hop_stats_session_up_count_get_elem(
+	const char *xpath, const void *list_entry);
+struct yang_data *
+bfdd_bfd_sessions_multi_hop_stats_control_packet_input_count_get_elem(
+	const char *xpath, const void *list_entry);
+struct yang_data *
+bfdd_bfd_sessions_multi_hop_stats_control_packet_output_count_get_elem(
+	const char *xpath, const void *list_entry);
+struct yang_data *
+bfdd_bfd_sessions_multi_hop_stats_negotiated_echo_transmission_interval_get_elem(
+	const char *xpath, const void *list_entry);
+struct yang_data *
+bfdd_bfd_sessions_multi_hop_stats_echo_packet_input_count_get_elem(
+	const char *xpath, const void *list_entry);
+struct yang_data *
+bfdd_bfd_sessions_multi_hop_stats_echo_packet_output_count_get_elem(
+	const char *xpath, const void *list_entry);
+
+/* Optional 'cli_show' callbacks. */
+void bfd_cli_show_header(struct vty *vty, struct lyd_node *dnode,
+			 bool show_defaults);
+void bfd_cli_show_header_end(struct vty *vty, struct lyd_node *dnode);
+void bfd_cli_show_single_hop_peer(struct vty *vty, struct lyd_node *dnode,
+				  bool show_defaults);
+void bfd_cli_show_multi_hop_peer(struct vty *vty, struct lyd_node *dnode,
+				 bool show_defaults);
+void bfd_cli_show_peer_end(struct vty *vty, struct lyd_node *dnode);
+void bfd_cli_show_mult(struct vty *vty, struct lyd_node *dnode,
+		       bool show_defaults);
+void bfd_cli_show_tx(struct vty *vty, struct lyd_node *dnode,
+		     bool show_defaults);
+void bfd_cli_show_rx(struct vty *vty, struct lyd_node *dnode,
+		     bool show_defaults);
+void bfd_cli_show_shutdown(struct vty *vty, struct lyd_node *dnode,
+			   bool show_defaults);
+void bfd_cli_show_echo(struct vty *vty, struct lyd_node *dnode,
+		       bool show_defaults);
+void bfd_cli_show_echo_interval(struct vty *vty, struct lyd_node *dnode,
+				bool show_defaults);
+
+#endif /* _FRR_BFDD_NB_H_ */
diff --git a/bfdd/bfdd_nb_config.c b/bfdd/bfdd_nb_config.c
new file mode 100644
index 000000000..50f953115
--- /dev/null
+++ b/bfdd/bfdd_nb_config.c
@@ -0,0 +1,520 @@
+/*
+ * BFD daemon northbound implementation.
+ *
+ * Copyright (C) 2019 Network Device Education Foundation, Inc. ("NetDEF")
+ *                    Rafael Zalamena
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301 USA.
+ */
+
+#include <zebra.h>
+
+#include "lib/log.h"
+#include "lib/northbound.h"
+
+#include "bfd.h"
+#include "bfdd_nb.h"
+
+/*
+ * Helpers.
+ */
+static void bfd_session_get_key(bool mhop, const struct lyd_node *dnode,
+				struct bfd_key *bk)
+{
+	const char *ifname = NULL, *vrfname = NULL;
+	struct sockaddr_any psa, lsa;
+
+	/* Required destination parameter. */
+	strtosa(yang_dnode_get_string(dnode, "./dest-addr"), &psa);
+
+	/* Get optional source address. */
+	memset(&lsa, 0, sizeof(lsa));
+	if (yang_dnode_exists(dnode, "./source-addr"))
+		strtosa(yang_dnode_get_string(dnode, "./source-addr"), &lsa);
+
+	/* Get optional interface and vrf names. */
+	if (yang_dnode_exists(dnode, "./interface"))
+		ifname = yang_dnode_get_string(dnode, "./interface");
+	if (yang_dnode_exists(dnode, "./vrf"))
+		vrfname = yang_dnode_get_string(dnode, "./vrf");
+
+	/* Generate the corresponding key. */
+	gen_bfd_key(bk, &psa, &lsa, mhop, ifname, vrfname);
+}
+
+static int bfd_session_create(enum nb_event event, const struct lyd_node *dnode,
+			      union nb_resource *resource, bool mhop)
+{
+	struct bfd_session *bs;
+	const char *ifname;
+	struct bfd_key bk;
+	struct prefix p;
+
+	switch (event) {
+	case NB_EV_VALIDATE:
+		/*
+		 * When `dest-addr` is IPv6 and link-local we must
+		 * require interface name, otherwise we can't figure
+		 * which interface to use to send the packets.
+		 */
+		yang_dnode_get_prefix(&p, dnode, "./dest-addr");
+
+		/*
+		 * To support old FRR versions we must allow empty
+		 * interface to be specified, however that should
+		 * change in the future.
+		 */
+		if (yang_dnode_exists(dnode, "./interface"))
+			ifname = yang_dnode_get_string(dnode, "./interface");
+		else
+			ifname = "";
+
+		if (p.family == AF_INET6 && IN6_IS_ADDR_LINKLOCAL(&p.u.prefix6)
+		    && strlen(ifname) == 0) {
+			zlog_warn(
+				"%s: when using link-local you must specify "
+				"an interface.",
+				__func__);
+			return NB_ERR_VALIDATION;
+		}
+		break;
+
+	case NB_EV_PREPARE:
+		bfd_session_get_key(mhop, dnode, &bk);
+		bs = bfd_key_lookup(bk);
+
+		/* This session was already configured by another daemon. */
+		if (bs != NULL) {
+			/* Now it is configured also by CLI. */
+			BFD_SET_FLAG(bs->flags, BFD_SESS_FLAG_CONFIG);
+			bs->refcount++;
+
+			resource->ptr = bs;
+			break;
+		}
+
+		bs = bfd_session_new();
+		if (bs == NULL)
+			return NB_ERR_RESOURCE;
+
+		/* Fill the session key. */
+		bfd_session_get_key(mhop, dnode, &bs->key);
+
+		/* Set configuration flags. */
+		bs->refcount = 1;
+		BFD_SET_FLAG(bs->flags, BFD_SESS_FLAG_CONFIG);
+		if (mhop)
+			BFD_SET_FLAG(bs->flags, BFD_SESS_FLAG_MH);
+		if (bs->key.family == AF_INET6)
+			BFD_SET_FLAG(bs->flags, BFD_SESS_FLAG_IPV6);
+
+		resource->ptr = bs;
+		break;
+
+	case NB_EV_APPLY:
+		bs = resource->ptr;
+
+		/* Only attempt to registrate if freshly allocated. */
+		if (bs->discrs.my_discr == 0 && bs_registrate(bs) == NULL)
+			return NB_ERR_RESOURCE;
+
+		nb_running_set_entry(dnode, bs);
+		break;
+
+	case NB_EV_ABORT:
+		bs = resource->ptr;
+		if (bs->refcount <= 1)
+			bfd_session_free(resource->ptr);
+		break;
+	}
+
+	return NB_OK;
+}
+
+static int bfd_session_destroy(enum nb_event event,
+			       const struct lyd_node *dnode, bool mhop)
+{
+	struct bfd_session *bs;
+	struct bfd_key bk;
+
+	switch (event) {
+	case NB_EV_VALIDATE:
+		bfd_session_get_key(mhop, dnode, &bk);
+		if (bfd_key_lookup(bk) == NULL)
+			return NB_ERR_INCONSISTENCY;
+		break;
+
+	case NB_EV_PREPARE:
+		/* NOTHING */
+		break;
+
+	case NB_EV_APPLY:
+		bs = nb_running_unset_entry(dnode);
+		/* CLI is not using this session anymore. */
+		if (BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_CONFIG) == 0)
+			break;
+
+		BFD_UNSET_FLAG(bs->flags, BFD_SESS_FLAG_CONFIG);
+		bs->refcount--;
+		/* There are still daemons using it. */
+		if (bs->refcount > 0)
+			break;
+
+		bfd_session_free(bs);
+		break;
+
+	case NB_EV_ABORT:
+		/* NOTHING */
+		break;
+	}
+
+	return NB_OK;
+}
+
+/*
+ * XPath: /frr-bfdd:bfdd/bfd
+ */
+int bfdd_bfd_create(enum nb_event event,
+		    const struct lyd_node *dnode __attribute__((__unused__)),
+		    union nb_resource *resource __attribute__((__unused__)))
+{
+	/* NOTHING */
+	return NB_OK;
+}
+
+int bfdd_bfd_destroy(enum nb_event event, const struct lyd_node *dnode)
+{
+	switch (event) {
+	case NB_EV_VALIDATE:
+		/* NOTHING */
+		return NB_OK;
+
+	case NB_EV_PREPARE:
+		/* NOTHING */
+		return NB_OK;
+
+	case NB_EV_APPLY:
+		bfd_sessions_remove_manual();
+		break;
+
+	case NB_EV_ABORT:
+		/* NOTHING */
+		return NB_OK;
+	}
+
+	return NB_OK;
+}
+
+/*
+ * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop
+ */
+int bfdd_bfd_sessions_single_hop_create(enum nb_event event,
+					const struct lyd_node *dnode,
+					union nb_resource *resource)
+{
+	return bfd_session_create(event, dnode, resource, false);
+}
+
+int bfdd_bfd_sessions_single_hop_destroy(enum nb_event event,
+					 const struct lyd_node *dnode)
+{
+	return bfd_session_destroy(event, dnode, false);
+}
+
+/*
+ * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/source-addr
+ */
+int bfdd_bfd_sessions_single_hop_source_addr_modify(enum nb_event event
+						    __attribute__((__unused__)),
+						    const struct lyd_node *dnode
+						    __attribute__((__unused__)),
+						    union nb_resource *resource
+						    __attribute__((__unused__)))
+{
+	return NB_OK;
+}
+
+int bfdd_bfd_sessions_single_hop_source_addr_destroy(
+	enum nb_event event __attribute__((__unused__)),
+	const struct lyd_node *dnode __attribute__((__unused__)))
+{
+	return NB_OK;
+}
+
+/*
+ * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/detection-multiplier
+ */
+int bfdd_bfd_sessions_single_hop_detection_multiplier_modify(
+	enum nb_event event, const struct lyd_node *dnode,
+	union nb_resource *resource __attribute__((__unused__)))
+{
+	uint8_t detection_multiplier = yang_dnode_get_uint8(dnode, NULL);
+	struct bfd_session *bs;
+
+	switch (event) {
+	case NB_EV_VALIDATE:
+		break;
+
+	case NB_EV_PREPARE:
+		/* NOTHING */
+		break;
+
+	case NB_EV_APPLY:
+		bs = nb_running_get_entry(dnode, NULL, true);
+		bs->detect_mult = detection_multiplier;
+		break;
+
+	case NB_EV_ABORT:
+		/* NOTHING */
+		break;
+	}
+
+	return NB_OK;
+}
+
+/*
+ * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/desired-transmission-interval
+ */
+int bfdd_bfd_sessions_single_hop_desired_transmission_interval_modify(
+	enum nb_event event, const struct lyd_node *dnode,
+	union nb_resource *resource __attribute__((__unused__)))
+{
+	uint32_t tx_interval = yang_dnode_get_uint32(dnode, NULL);
+	struct bfd_session *bs;
+
+	switch (event) {
+	case NB_EV_VALIDATE:
+		if (tx_interval < 10000 || tx_interval > 60000000)
+			return NB_ERR_VALIDATION;
+		break;
+
+	case NB_EV_PREPARE:
+		/* NOTHING */
+		break;
+
+	case NB_EV_APPLY:
+		bs = nb_running_get_entry(dnode, NULL, true);
+		if (tx_interval == bs->timers.desired_min_tx)
+			return NB_OK;
+
+		bs->timers.desired_min_tx = tx_interval;
+		bfd_set_polling(bs);
+		break;
+
+	case NB_EV_ABORT:
+		/* NOTHING */
+		break;
+	}
+
+	return NB_OK;
+}
+
+/*
+ * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/required-receive-interval
+ */
+int bfdd_bfd_sessions_single_hop_required_receive_interval_modify(
+	enum nb_event event, const struct lyd_node *dnode,
+	union nb_resource *resource __attribute__((__unused__)))
+{
+	uint32_t rx_interval = yang_dnode_get_uint32(dnode, NULL);
+	struct bfd_session *bs;
+
+	switch (event) {
+	case NB_EV_VALIDATE:
+		if (rx_interval < 10000 || rx_interval > 60000000)
+			return NB_ERR_VALIDATION;
+		break;
+
+	case NB_EV_PREPARE:
+		/* NOTHING */
+		break;
+
+	case NB_EV_APPLY:
+		bs = nb_running_get_entry(dnode, NULL, true);
+		if (rx_interval == bs->timers.required_min_rx)
+			return NB_OK;
+
+		bs->timers.required_min_rx = rx_interval;
+		bfd_set_polling(bs);
+		break;
+
+	case NB_EV_ABORT:
+		/* NOTHING */
+		break;
+	}
+
+	return NB_OK;
+}
+
+/*
+ * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/administrative-down
+ */
+int bfdd_bfd_sessions_single_hop_administrative_down_modify(
+	enum nb_event event, const struct lyd_node *dnode,
+	union nb_resource *resource __attribute__((__unused__)))
+{
+	bool shutdown = yang_dnode_get_bool(dnode, NULL);
+	struct bfd_session *bs;
+
+	switch (event) {
+	case NB_EV_VALIDATE:
+	case NB_EV_PREPARE:
+		return NB_OK;
+
+	case NB_EV_APPLY:
+		break;
+
+	case NB_EV_ABORT:
+		return NB_OK;
+	}
+
+	bs = nb_running_get_entry(dnode, NULL, true);
+
+	if (shutdown == false) {
+		if (!BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_SHUTDOWN))
+			return NB_OK;
+
+		BFD_UNSET_FLAG(bs->flags, BFD_SESS_FLAG_SHUTDOWN);
+
+		/* Change and notify state change. */
+		bs->ses_state = PTM_BFD_DOWN;
+		control_notify(bs, bs->ses_state);
+
+		/* Enable all timers. */
+		bfd_recvtimer_update(bs);
+		bfd_xmttimer_update(bs, bs->xmt_TO);
+		if (BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_ECHO)) {
+			bfd_echo_recvtimer_update(bs);
+			bfd_echo_xmttimer_update(bs, bs->echo_xmt_TO);
+		}
+	} else {
+		if (BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_SHUTDOWN))
+			return NB_OK;
+
+		BFD_SET_FLAG(bs->flags, BFD_SESS_FLAG_SHUTDOWN);
+
+		/* Disable all events. */
+		bfd_recvtimer_delete(bs);
+		bfd_echo_recvtimer_delete(bs);
+		bfd_xmttimer_delete(bs);
+		bfd_echo_xmttimer_delete(bs);
+
+		/* Change and notify state change. */
+		bs->ses_state = PTM_BFD_ADM_DOWN;
+		control_notify(bs, bs->ses_state);
+
+		ptm_bfd_snd(bs, 0);
+	}
+
+	return NB_OK;
+}
+
+/*
+ * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/echo-mode
+ */
+int bfdd_bfd_sessions_single_hop_echo_mode_modify(enum nb_event event,
+						  const struct lyd_node *dnode,
+						  union nb_resource *resource
+						  __attribute__((__unused__)))
+{
+	bool echo = yang_dnode_get_bool(dnode, NULL);
+	struct bfd_session *bs;
+
+	switch (event) {
+	case NB_EV_VALIDATE:
+	case NB_EV_PREPARE:
+		return NB_OK;
+
+	case NB_EV_APPLY:
+		break;
+
+	case NB_EV_ABORT:
+		return NB_OK;
+	}
+
+	bs = nb_running_get_entry(dnode, NULL, true);
+
+	if (echo == false) {
+		if (!BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_ECHO))
+			return NB_OK;
+
+		BFD_UNSET_FLAG(bs->flags, BFD_SESS_FLAG_ECHO);
+		ptm_bfd_echo_stop(bs);
+	} else {
+		if (BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_ECHO))
+			return NB_OK;
+
+		BFD_SET_FLAG(bs->flags, BFD_SESS_FLAG_ECHO);
+		/* Apply setting immediately. */
+		if (!BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_SHUTDOWN))
+			bs_echo_timer_handler(bs);
+	}
+
+	return NB_OK;
+}
+
+/*
+ * XPath:
+ * /frr-bfdd:bfdd/bfd/sessions/single-hop/desired-echo-transmission-interval
+ */
+int bfdd_bfd_sessions_single_hop_desired_echo_transmission_interval_modify(
+	enum nb_event event, const struct lyd_node *dnode,
+	union nb_resource *resource __attribute__((__unused__)))
+{
+	uint32_t echo_interval = yang_dnode_get_uint32(dnode, NULL);
+	struct bfd_session *bs;
+
+	switch (event) {
+	case NB_EV_VALIDATE:
+		if (echo_interval < 10000 || echo_interval > 60000000)
+			return NB_ERR_VALIDATION;
+		break;
+
+	case NB_EV_PREPARE:
+		/* NOTHING */
+		break;
+
+	case NB_EV_APPLY:
+		bs = nb_running_get_entry(dnode, NULL, true);
+		if (echo_interval == bs->timers.required_min_echo)
+			return NB_OK;
+
+		bs->timers.required_min_echo = echo_interval;
+		break;
+
+	case NB_EV_ABORT:
+		/* NOTHING */
+		break;
+	}
+
+	return NB_OK;
+}
+
+/*
+ * XPath: /frr-bfdd:bfdd/bfd/sessions/multi-hop
+ */
+int bfdd_bfd_sessions_multi_hop_create(enum nb_event event,
+				       const struct lyd_node *dnode,
+				       union nb_resource *resource)
+{
+	return bfd_session_create(event, dnode, resource, true);
+}
+
+int bfdd_bfd_sessions_multi_hop_destroy(enum nb_event event,
+					const struct lyd_node *dnode)
+{
+	return bfd_session_destroy(event, dnode, true);
+}
diff --git a/bfdd/bfdd_nb_state.c b/bfdd/bfdd_nb_state.c
new file mode 100644
index 000000000..dfca3d141
--- /dev/null
+++ b/bfdd/bfdd_nb_state.c
@@ -0,0 +1,383 @@
+/*
+ * BFD daemon northbound implementation.
+ *
+ * Copyright (C) 2019 Network Device Education Foundation, Inc. ("NetDEF")
+ *                    Rafael Zalamena
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301 USA.
+ */
+
+#include <zebra.h>
+
+#include "lib/log.h"
+#include "lib/northbound.h"
+
+#include "bfd.h"
+#include "bfdd_nb.h"
+
+/*
+ * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop
+ */
+const void *bfdd_bfd_sessions_single_hop_get_next(const void *parent_list_entry
+						  __attribute__((__unused__)),
+						  const void *list_entry)
+{
+	return bfd_session_next(list_entry, false);
+}
+
+int bfdd_bfd_sessions_single_hop_get_keys(const void *list_entry,
+					  struct yang_list_keys *keys)
+{
+	const struct bfd_session *bs = list_entry;
+	char dstbuf[INET6_ADDRSTRLEN];
+
+	inet_ntop(bs->key.family, &bs->key.peer, dstbuf, sizeof(dstbuf));
+
+	keys->num = 3;
+	strlcpy(keys->key[0], dstbuf, sizeof(keys->key[0]));
+	strlcpy(keys->key[1], bs->key.ifname, sizeof(keys->key[1]));
+	strlcpy(keys->key[2], bs->key.vrfname, sizeof(keys->key[2]));
+
+	return NB_OK;
+}
+
+const void *
+bfdd_bfd_sessions_single_hop_lookup_entry(const void *parent_list_entry
+					  __attribute__((__unused__)),
+					  const struct yang_list_keys *keys)
+{
+	const char *dest_addr = keys->key[0];
+	const char *ifname = keys->key[1];
+	const char *vrf = keys->key[2];
+	struct sockaddr_any psa, lsa;
+	struct bfd_key bk;
+
+	strtosa(dest_addr, &psa);
+	memset(&lsa, 0, sizeof(lsa));
+	gen_bfd_key(&bk, &psa, &lsa, false, ifname, vrf);
+
+	return bfd_key_lookup(bk);
+}
+
+/*
+ * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/local-discriminator
+ */
+struct yang_data *
+bfdd_bfd_sessions_single_hop_stats_local_discriminator_get_elem(
+	const char *xpath, const void *list_entry)
+{
+	const struct bfd_session *bs = list_entry;
+
+	return yang_data_new_uint32(xpath, bs->discrs.my_discr);
+}
+
+/*
+ * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/local-state
+ */
+struct yang_data *
+bfdd_bfd_sessions_single_hop_stats_local_state_get_elem(const char *xpath,
+							const void *list_entry)
+{
+	const struct bfd_session *bs = list_entry;
+
+	return yang_data_new_enum(xpath, bs->ses_state);
+}
+
+/*
+ * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/local-diagnostic
+ */
+struct yang_data *bfdd_bfd_sessions_single_hop_stats_local_diagnostic_get_elem(
+	const char *xpath, const void *list_entry)
+{
+	const struct bfd_session *bs = list_entry;
+
+	return yang_data_new_enum(xpath, bs->local_diag);
+}
+
+/*
+ * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/local-multiplier
+ */
+struct yang_data *bfdd_bfd_sessions_single_hop_stats_local_multiplier_get_elem(
+	const char *xpath, const void *list_entry)
+{
+	const struct bfd_session *bs = list_entry;
+
+	return yang_data_new_int8(xpath, bs->detect_mult);
+}
+
+/*
+ * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/remote-discriminator
+ */
+struct yang_data *
+bfdd_bfd_sessions_single_hop_stats_remote_discriminator_get_elem(
+	const char *xpath, const void *list_entry)
+{
+	const struct bfd_session *bs = list_entry;
+
+	if (bs->discrs.remote_discr == 0)
+		return NULL;
+
+	return yang_data_new_uint32(xpath, bs->discrs.remote_discr);
+}
+
+/*
+ * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/remote-state
+ */
+struct yang_data *
+bfdd_bfd_sessions_single_hop_stats_remote_state_get_elem(const char *xpath,
+							 const void *list_entry)
+{
+	const struct bfd_session *bs = list_entry;
+
+	return yang_data_new_enum(xpath, bs->ses_state);
+}
+
+/*
+ * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/remote-diagnostic
+ */
+struct yang_data *bfdd_bfd_sessions_single_hop_stats_remote_diagnostic_get_elem(
+	const char *xpath, const void *list_entry)
+{
+	const struct bfd_session *bs = list_entry;
+
+	return yang_data_new_enum(xpath, bs->remote_diag);
+}
+
+/*
+ * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/remote-multiplier
+ */
+struct yang_data *bfdd_bfd_sessions_single_hop_stats_remote_multiplier_get_elem(
+	const char *xpath, const void *list_entry)
+{
+	const struct bfd_session *bs = list_entry;
+
+	return yang_data_new_int8(xpath, bs->remote_detect_mult);
+}
+
+/*
+ * XPath:
+ * /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/negotiated-transmission-interval
+ */
+struct yang_data *
+bfdd_bfd_sessions_single_hop_stats_negotiated_transmission_interval_get_elem(
+	const char *xpath, const void *list_entry)
+{
+	const struct bfd_session *bs = list_entry;
+
+	return yang_data_new_uint32(xpath, bs->remote_timers.desired_min_tx);
+}
+
+/*
+ * XPath:
+ * /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/negotiated-receive-interval
+ */
+struct yang_data *
+bfdd_bfd_sessions_single_hop_stats_negotiated_receive_interval_get_elem(
+	const char *xpath, const void *list_entry)
+{
+	const struct bfd_session *bs = list_entry;
+
+	return yang_data_new_uint32(xpath, bs->remote_timers.required_min_rx);
+}
+
+/*
+ * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/detection-mode
+ */
+struct yang_data *bfdd_bfd_sessions_single_hop_stats_detection_mode_get_elem(
+	const char *xpath, const void *list_entry)
+{
+	const struct bfd_session *bs = list_entry;
+	int detection_mode;
+
+	/*
+	 * Detection mode:
+	 *   1. Async with echo
+	 *   2. Async without echo
+	 *   3. Demand with echo
+	 *   4. Demand without echo
+	 *
+	 * TODO: support demand mode.
+	 */
+	if (BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_ECHO))
+		detection_mode = 1;
+	else
+		detection_mode = 2;
+
+	return yang_data_new_enum(xpath, detection_mode);
+}
+
+/*
+ * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/last-down-time
+ */
+struct yang_data *bfdd_bfd_sessions_single_hop_stats_last_down_time_get_elem(
+	const char *xpath __attribute__((__unused__)),
+	const void *list_entry __attribute__((__unused__)))
+{
+	/*
+	 * TODO: implement me.
+	 *
+	 * No yang support for time elements yet.
+	 */
+	return NULL;
+}
+
+/*
+ * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/last-up-time
+ */
+struct yang_data *bfdd_bfd_sessions_single_hop_stats_last_up_time_get_elem(
+	const char *xpath __attribute__((__unused__)),
+	const void *list_entry __attribute__((__unused__)))
+{
+	/*
+	 * TODO: implement me.
+	 *
+	 * No yang support for time elements yet.
+	 */
+	return NULL;
+}
+
+/*
+ * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/session-down-count
+ */
+struct yang_data *
+bfdd_bfd_sessions_single_hop_stats_session_down_count_get_elem(
+	const char *xpath, const void *list_entry)
+{
+	const struct bfd_session *bs = list_entry;
+
+	return yang_data_new_uint64(xpath, bs->stats.session_down);
+}
+
+/*
+ * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/session-up-count
+ */
+struct yang_data *bfdd_bfd_sessions_single_hop_stats_session_up_count_get_elem(
+	const char *xpath, const void *list_entry)
+{
+	const struct bfd_session *bs = list_entry;
+
+	return yang_data_new_uint64(xpath, bs->stats.session_up);
+}
+
+/*
+ * XPath:
+ * /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/control-packet-input-count
+ */
+struct yang_data *
+bfdd_bfd_sessions_single_hop_stats_control_packet_input_count_get_elem(
+	const char *xpath, const void *list_entry)
+{
+	const struct bfd_session *bs = list_entry;
+
+	return yang_data_new_uint64(xpath, bs->stats.rx_ctrl_pkt);
+}
+
+/*
+ * XPath:
+ * /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/control-packet-output-count
+ */
+struct yang_data *
+bfdd_bfd_sessions_single_hop_stats_control_packet_output_count_get_elem(
+	const char *xpath, const void *list_entry)
+{
+	const struct bfd_session *bs = list_entry;
+
+	return yang_data_new_uint64(xpath, bs->stats.tx_ctrl_pkt);
+}
+
+/*
+ * XPath:
+ * /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/negotiated-echo-transmission-interval
+ */
+struct yang_data *
+bfdd_bfd_sessions_single_hop_stats_negotiated_echo_transmission_interval_get_elem(
+	const char *xpath, const void *list_entry)
+{
+	const struct bfd_session *bs = list_entry;
+
+	return yang_data_new_uint32(xpath, bs->remote_timers.required_min_echo);
+}
+
+/*
+ * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/echo-packet-input-count
+ */
+struct yang_data *
+bfdd_bfd_sessions_single_hop_stats_echo_packet_input_count_get_elem(
+	const char *xpath, const void *list_entry)
+{
+	const struct bfd_session *bs = list_entry;
+
+	return yang_data_new_uint64(xpath, bs->stats.rx_echo_pkt);
+}
+
+/*
+ * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/echo-packet-output-count
+ */
+struct yang_data *
+bfdd_bfd_sessions_single_hop_stats_echo_packet_output_count_get_elem(
+	const char *xpath, const void *list_entry)
+{
+	const struct bfd_session *bs = list_entry;
+
+	return yang_data_new_uint64(xpath, bs->stats.tx_echo_pkt);
+}
+
+/*
+ * XPath: /frr-bfdd:bfdd/bfd/sessions/multi-hop
+ */
+const void *bfdd_bfd_sessions_multi_hop_get_next(const void *parent_list_entry
+						 __attribute__((__unused__)),
+						 const void *list_entry)
+{
+	return bfd_session_next(list_entry, true);
+}
+
+int bfdd_bfd_sessions_multi_hop_get_keys(const void *list_entry,
+					 struct yang_list_keys *keys)
+{
+	const struct bfd_session *bs = list_entry;
+	char dstbuf[INET6_ADDRSTRLEN], srcbuf[INET6_ADDRSTRLEN];
+
+	inet_ntop(bs->key.family, &bs->key.peer, dstbuf, sizeof(dstbuf));
+	inet_ntop(bs->key.family, &bs->key.local, srcbuf, sizeof(srcbuf));
+
+	keys->num = 4;
+	strlcpy(keys->key[0], srcbuf, sizeof(keys->key[0]));
+	strlcpy(keys->key[1], dstbuf, sizeof(keys->key[1]));
+	strlcpy(keys->key[2], bs->key.ifname, sizeof(keys->key[2]));
+	strlcpy(keys->key[3], bs->key.vrfname, sizeof(keys->key[3]));
+
+	return NB_OK;
+}
+
+const void *
+bfdd_bfd_sessions_multi_hop_lookup_entry(const void *parent_list_entry
+					 __attribute__((__unused__)),
+					 const struct yang_list_keys *keys)
+{
+	const char *source_addr = keys->key[0];
+	const char *dest_addr = keys->key[1];
+	const char *ifname = keys->key[2];
+	const char *vrf = keys->key[3];
+	struct sockaddr_any psa, lsa;
+	struct bfd_key bk;
+
+	strtosa(dest_addr, &psa);
+	strtosa(source_addr, &lsa);
+	gen_bfd_key(&bk, &psa, &lsa, true, ifname, vrf);
+
+	return bfd_key_lookup(bk);
+}
diff --git a/bfdd/bfdd_northbound.c b/bfdd/bfdd_northbound.c
deleted file mode 100644
index edbd40691..000000000
--- a/bfdd/bfdd_northbound.c
+++ /dev/null
@@ -1,1236 +0,0 @@
-/*
- * BFD daemon northbound implementation.
- *
- * Copyright (C) 2019 Network Device Education Foundation, Inc. ("NetDEF")
- *                    Rafael Zalamena
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
- * 02110-1301 USA.
- */
-
-#include <zebra.h>
-
-#include "lib/log.h"
-#include "lib/northbound.h"
-
-#include "bfd.h"
-
-/*
- * Helpers.
- */
-static void bfd_session_get_key(bool mhop, const struct lyd_node *dnode,
-				struct bfd_key *bk)
-{
-	const char *ifname = NULL, *vrfname = NULL;
-	struct sockaddr_any psa, lsa;
-
-	/* Required destination parameter. */
-	strtosa(yang_dnode_get_string(dnode, "./dest-addr"), &psa);
-
-	/* Get optional source address. */
-	memset(&lsa, 0, sizeof(lsa));
-	if (yang_dnode_exists(dnode, "./source-addr"))
-		strtosa(yang_dnode_get_string(dnode, "./source-addr"), &lsa);
-
-	/* Get optional interface and vrf names. */
-	if (yang_dnode_exists(dnode, "./interface"))
-		ifname = yang_dnode_get_string(dnode, "./interface");
-	if (yang_dnode_exists(dnode, "./vrf"))
-		vrfname = yang_dnode_get_string(dnode, "./vrf");
-
-	/* Generate the corresponding key. */
-	gen_bfd_key(bk, &psa, &lsa, mhop, ifname, vrfname);
-}
-
-static int bfd_session_create(enum nb_event event, const struct lyd_node *dnode,
-			      union nb_resource *resource, bool mhop)
-{
-	struct bfd_session *bs;
-	const char *ifname;
-	struct bfd_key bk;
-	struct prefix p;
-
-	switch (event) {
-	case NB_EV_VALIDATE:
-		/*
-		 * When `dest-addr` is IPv6 and link-local we must
-		 * require interface name, otherwise we can't figure
-		 * which interface to use to send the packets.
-		 */
-		yang_dnode_get_prefix(&p, dnode, "./dest-addr");
-
-		/*
-		 * To support old FRR versions we must allow empty
-		 * interface to be specified, however that should
-		 * change in the future.
-		 */
-		if (yang_dnode_exists(dnode, "./interface"))
-			ifname = yang_dnode_get_string(dnode, "./interface");
-		else
-			ifname = "";
-
-		if (p.family == AF_INET6
-		    && IN6_IS_ADDR_LINKLOCAL(&p.u.prefix6)
-		    && strlen(ifname) == 0) {
-			zlog_warn("%s: when using link-local you must specify "
-				  "an interface.", __func__);
-			return NB_ERR_VALIDATION;
-		}
-		break;
-
-	case NB_EV_PREPARE:
-		bfd_session_get_key(mhop, dnode, &bk);
-		bs = bfd_key_lookup(bk);
-
-		/* This session was already configured by another daemon. */
-		if (bs != NULL) {
-			/* Now it is configured also by CLI. */
-			BFD_SET_FLAG(bs->flags, BFD_SESS_FLAG_CONFIG);
-			bs->refcount++;
-
-			resource->ptr = bs;
-			break;
-		}
-
-		bs = bfd_session_new();
-		if (bs == NULL)
-			return NB_ERR_RESOURCE;
-
-		/* Fill the session key. */
-		bfd_session_get_key(mhop, dnode, &bs->key);
-
-		/* Set configuration flags. */
-		bs->refcount = 1;
-		BFD_SET_FLAG(bs->flags, BFD_SESS_FLAG_CONFIG);
-		if (mhop)
-			BFD_SET_FLAG(bs->flags, BFD_SESS_FLAG_MH);
-		if (bs->key.family == AF_INET6)
-			BFD_SET_FLAG(bs->flags, BFD_SESS_FLAG_IPV6);
-
-		resource->ptr = bs;
-		break;
-
-	case NB_EV_APPLY:
-		bs = resource->ptr;
-
-		/* Only attempt to registrate if freshly allocated. */
-		if (bs->discrs.my_discr == 0 && bs_registrate(bs) == NULL)
-			return NB_ERR_RESOURCE;
-
-		nb_running_set_entry(dnode, bs);
-		break;
-
-	case NB_EV_ABORT:
-		bs = resource->ptr;
-		if (bs->refcount <= 1)
-			bfd_session_free(resource->ptr);
-		break;
-	}
-
-	return NB_OK;
-}
-
-static int bfd_session_destroy(enum nb_event event,
-			       const struct lyd_node *dnode, bool mhop)
-{
-	struct bfd_session *bs;
-	struct bfd_key bk;
-
-	switch (event) {
-	case NB_EV_VALIDATE:
-		bfd_session_get_key(mhop, dnode, &bk);
-		if (bfd_key_lookup(bk) == NULL)
-			return NB_ERR_INCONSISTENCY;
-		break;
-
-	case NB_EV_PREPARE:
-		/* NOTHING */
-		break;
-
-	case NB_EV_APPLY:
-		bs = nb_running_unset_entry(dnode);
-		/* CLI is not using this session anymore. */
-		if (BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_CONFIG) == 0)
-			break;
-
-		BFD_UNSET_FLAG(bs->flags, BFD_SESS_FLAG_CONFIG);
-		bs->refcount--;
-		/* There are still daemons using it. */
-		if (bs->refcount > 0)
-			break;
-
-		bfd_session_free(bs);
-		break;
-
-	case NB_EV_ABORT:
-		/* NOTHING */
-		break;
-	}
-
-	return NB_OK;
-}
-
-/*
- * XPath: /frr-bfdd:bfdd/bfd
- */
-static int bfdd_bfd_create(enum nb_event event,
-			   const struct lyd_node *dnode
-			   __attribute__((__unused__)),
-			   union nb_resource *resource
-			   __attribute__((__unused__)))
-{
-	/* NOTHING */
-	return NB_OK;
-}
-
-static int bfdd_bfd_destroy(enum nb_event event, const struct lyd_node *dnode)
-{
-	switch (event) {
-	case NB_EV_VALIDATE:
-		/* NOTHING */
-		return NB_OK;
-
-	case NB_EV_PREPARE:
-		/* NOTHING */
-		return NB_OK;
-
-	case NB_EV_APPLY:
-		bfd_sessions_remove_manual();
-		break;
-
-	case NB_EV_ABORT:
-		/* NOTHING */
-		return NB_OK;
-	}
-
-	return NB_OK;
-}
-
-/*
- * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop
- */
-static int bfdd_bfd_sessions_single_hop_create(enum nb_event event,
-					       const struct lyd_node *dnode,
-					       union nb_resource *resource)
-{
-	return bfd_session_create(event, dnode, resource, false);
-}
-
-static int bfdd_bfd_sessions_single_hop_destroy(enum nb_event event,
-						const struct lyd_node *dnode)
-{
-	return bfd_session_destroy(event, dnode, false);
-}
-
-static const void *
-bfdd_bfd_sessions_single_hop_get_next(const void *parent_list_entry
-				      __attribute__((__unused__)),
-				      const void *list_entry)
-{
-	return bfd_session_next(list_entry, false);
-}
-
-static int bfdd_bfd_sessions_single_hop_get_keys(const void *list_entry,
-						 struct yang_list_keys *keys)
-{
-	const struct bfd_session *bs = list_entry;
-	char dstbuf[INET6_ADDRSTRLEN];
-
-	inet_ntop(bs->key.family, &bs->key.peer, dstbuf, sizeof(dstbuf));
-
-	keys->num = 3;
-	strlcpy(keys->key[0], dstbuf, sizeof(keys->key[0]));
-	strlcpy(keys->key[1], bs->key.ifname, sizeof(keys->key[1]));
-	strlcpy(keys->key[2], bs->key.vrfname, sizeof(keys->key[2]));
-
-	return NB_OK;
-}
-
-static const void *
-bfdd_bfd_sessions_single_hop_lookup_entry(const void *parent_list_entry
-					  __attribute__((__unused__)),
-					  const struct yang_list_keys *keys)
-{
-	const char *dest_addr = keys->key[0];
-	const char *ifname = keys->key[1];
-	const char *vrf = keys->key[2];
-	struct sockaddr_any psa, lsa;
-	struct bfd_key bk;
-
-	strtosa(dest_addr, &psa);
-	memset(&lsa, 0, sizeof(lsa));
-	gen_bfd_key(&bk, &psa, &lsa, false, ifname, vrf);
-
-	return bfd_key_lookup(bk);
-}
-
-/*
- * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/source-addr
- */
-static int bfdd_bfd_sessions_single_hop_source_addr_modify(
-	enum nb_event event __attribute__((__unused__)),
-	const struct lyd_node *dnode __attribute__((__unused__)),
-	union nb_resource *resource __attribute__((__unused__)))
-{
-	return NB_OK;
-}
-
-static int bfdd_bfd_sessions_single_hop_source_addr_destroy(
-	enum nb_event event __attribute__((__unused__)),
-	const struct lyd_node *dnode __attribute__((__unused__)))
-{
-	return NB_OK;
-}
-
-/*
- * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/detection-multiplier
- */
-static int bfdd_bfd_sessions_single_hop_detection_multiplier_modify(
-	enum nb_event event, const struct lyd_node *dnode,
-	union nb_resource *resource __attribute__((__unused__)))
-{
-	uint8_t detection_multiplier = yang_dnode_get_uint8(dnode, NULL);
-	struct bfd_session *bs;
-
-	switch (event) {
-	case NB_EV_VALIDATE:
-		break;
-
-	case NB_EV_PREPARE:
-		/* NOTHING */
-		break;
-
-	case NB_EV_APPLY:
-		bs = nb_running_get_entry(dnode, NULL, true);
-		bs->detect_mult = detection_multiplier;
-		break;
-
-	case NB_EV_ABORT:
-		/* NOTHING */
-		break;
-	}
-
-	return NB_OK;
-}
-
-/*
- * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/desired-transmission-interval
- */
-static int bfdd_bfd_sessions_single_hop_desired_transmission_interval_modify(
-	enum nb_event event, const struct lyd_node *dnode,
-	union nb_resource *resource __attribute__((__unused__)))
-{
-	uint32_t tx_interval = yang_dnode_get_uint32(dnode, NULL);
-	struct bfd_session *bs;
-
-	switch (event) {
-	case NB_EV_VALIDATE:
-		if (tx_interval < 10000 || tx_interval > 60000000)
-			return NB_ERR_VALIDATION;
-		break;
-
-	case NB_EV_PREPARE:
-		/* NOTHING */
-		break;
-
-	case NB_EV_APPLY:
-		bs = nb_running_get_entry(dnode, NULL, true);
-		if (tx_interval == bs->timers.desired_min_tx)
-			return NB_OK;
-
-		bs->timers.desired_min_tx = tx_interval;
-		bfd_set_polling(bs);
-		break;
-
-	case NB_EV_ABORT:
-		/* NOTHING */
-		break;
-	}
-
-	return NB_OK;
-}
-
-/*
- * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/required-receive-interval
- */
-static int bfdd_bfd_sessions_single_hop_required_receive_interval_modify(
-	enum nb_event event, const struct lyd_node *dnode,
-	union nb_resource *resource __attribute__((__unused__)))
-{
-	uint32_t rx_interval = yang_dnode_get_uint32(dnode, NULL);
-	struct bfd_session *bs;
-
-	switch (event) {
-	case NB_EV_VALIDATE:
-		if (rx_interval < 10000 || rx_interval > 60000000)
-			return NB_ERR_VALIDATION;
-		break;
-
-	case NB_EV_PREPARE:
-		/* NOTHING */
-		break;
-
-	case NB_EV_APPLY:
-		bs = nb_running_get_entry(dnode, NULL, true);
-		if (rx_interval == bs->timers.required_min_rx)
-			return NB_OK;
-
-		bs->timers.required_min_rx = rx_interval;
-		bfd_set_polling(bs);
-		break;
-
-	case NB_EV_ABORT:
-		/* NOTHING */
-		break;
-	}
-
-	return NB_OK;
-}
-
-/*
- * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/administrative-down
- */
-static int bfdd_bfd_sessions_single_hop_administrative_down_modify(
-	enum nb_event event, const struct lyd_node *dnode,
-	union nb_resource *resource __attribute__((__unused__)))
-{
-	bool shutdown = yang_dnode_get_bool(dnode, NULL);
-	struct bfd_session *bs;
-
-	switch (event) {
-	case NB_EV_VALIDATE:
-	case NB_EV_PREPARE:
-		return NB_OK;
-
-	case NB_EV_APPLY:
-		break;
-
-	case NB_EV_ABORT:
-		return NB_OK;
-	}
-
-	bs = nb_running_get_entry(dnode, NULL, true);
-
-	if (shutdown == false) {
-		if (!BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_SHUTDOWN))
-			return NB_OK;
-
-		BFD_UNSET_FLAG(bs->flags, BFD_SESS_FLAG_SHUTDOWN);
-
-		/* Change and notify state change. */
-		bs->ses_state = PTM_BFD_DOWN;
-		control_notify(bs, bs->ses_state);
-
-		/* Enable all timers. */
-		bfd_recvtimer_update(bs);
-		bfd_xmttimer_update(bs, bs->xmt_TO);
-		if (BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_ECHO)) {
-			bfd_echo_recvtimer_update(bs);
-			bfd_echo_xmttimer_update(bs, bs->echo_xmt_TO);
-		}
-	} else {
-		if (BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_SHUTDOWN))
-			return NB_OK;
-
-		BFD_SET_FLAG(bs->flags, BFD_SESS_FLAG_SHUTDOWN);
-
-		/* Disable all events. */
-		bfd_recvtimer_delete(bs);
-		bfd_echo_recvtimer_delete(bs);
-		bfd_xmttimer_delete(bs);
-		bfd_echo_xmttimer_delete(bs);
-
-		/* Change and notify state change. */
-		bs->ses_state = PTM_BFD_ADM_DOWN;
-		control_notify(bs, bs->ses_state);
-
-		ptm_bfd_snd(bs, 0);
-	}
-
-	return NB_OK;
-}
-
-/*
- * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/echo-mode
- */
-static int bfdd_bfd_sessions_single_hop_echo_mode_modify(
-	enum nb_event event, const struct lyd_node *dnode,
-	union nb_resource *resource __attribute__((__unused__)))
-{
-	bool echo = yang_dnode_get_bool(dnode, NULL);
-	struct bfd_session *bs;
-
-	switch (event) {
-	case NB_EV_VALIDATE:
-	case NB_EV_PREPARE:
-		return NB_OK;
-
-	case NB_EV_APPLY:
-		break;
-
-	case NB_EV_ABORT:
-		return NB_OK;
-	}
-
-	bs = nb_running_get_entry(dnode, NULL, true);
-
-	if (echo == false) {
-		if (!BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_ECHO))
-			return NB_OK;
-
-		BFD_UNSET_FLAG(bs->flags, BFD_SESS_FLAG_ECHO);
-		ptm_bfd_echo_stop(bs);
-	} else {
-		if (BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_ECHO))
-			return NB_OK;
-
-		BFD_SET_FLAG(bs->flags, BFD_SESS_FLAG_ECHO);
-		/* Apply setting immediately. */
-		if (!BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_SHUTDOWN))
-			bs_echo_timer_handler(bs);
-	}
-
-	return NB_OK;
-}
-
-/*
- * XPath:
- * /frr-bfdd:bfdd/bfd/sessions/single-hop/desired-echo-transmission-interval
- */
-static int
-bfdd_bfd_sessions_single_hop_desired_echo_transmission_interval_modify(
-	enum nb_event event, const struct lyd_node *dnode,
-	union nb_resource *resource __attribute__((__unused__)))
-{
-	uint32_t echo_interval = yang_dnode_get_uint32(dnode, NULL);
-	struct bfd_session *bs;
-
-	switch (event) {
-	case NB_EV_VALIDATE:
-		if (echo_interval < 10000 || echo_interval > 60000000)
-			return NB_ERR_VALIDATION;
-		break;
-
-	case NB_EV_PREPARE:
-		/* NOTHING */
-		break;
-
-	case NB_EV_APPLY:
-		bs = nb_running_get_entry(dnode, NULL, true);
-		if (echo_interval == bs->timers.required_min_echo)
-			return NB_OK;
-
-		bs->timers.required_min_echo = echo_interval;
-		break;
-
-	case NB_EV_ABORT:
-		/* NOTHING */
-		break;
-	}
-
-	return NB_OK;
-}
-
-/*
- * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/local-discriminator
- */
-static struct yang_data *
-bfdd_bfd_sessions_single_hop_stats_local_discriminator_get_elem(
-	const char *xpath, const void *list_entry)
-{
-	const struct bfd_session *bs = list_entry;
-
-	return yang_data_new_uint32(xpath, bs->discrs.my_discr);
-}
-
-/*
- * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/local-state
- */
-static struct yang_data *
-bfdd_bfd_sessions_single_hop_stats_local_state_get_elem(const char *xpath,
-							const void *list_entry)
-{
-	const struct bfd_session *bs = list_entry;
-
-	return yang_data_new_enum(xpath, bs->ses_state);
-}
-
-/*
- * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/local-diagnostic
- */
-static struct yang_data *
-bfdd_bfd_sessions_single_hop_stats_local_diagnostic_get_elem(
-	const char *xpath, const void *list_entry)
-{
-	const struct bfd_session *bs = list_entry;
-
-	return yang_data_new_enum(xpath, bs->local_diag);
-}
-
-/*
- * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/local-multiplier
- */
-static struct yang_data *
-bfdd_bfd_sessions_single_hop_stats_local_multiplier_get_elem(
-	const char *xpath, const void *list_entry)
-{
-	const struct bfd_session *bs = list_entry;
-
-	return yang_data_new_int8(xpath, bs->detect_mult);
-}
-
-/*
- * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/remote-discriminator
- */
-static struct yang_data *
-bfdd_bfd_sessions_single_hop_stats_remote_discriminator_get_elem(
-	const char *xpath, const void *list_entry)
-{
-	const struct bfd_session *bs = list_entry;
-
-	if (bs->discrs.remote_discr == 0)
-		return NULL;
-
-	return yang_data_new_uint32(xpath, bs->discrs.remote_discr);
-}
-
-/*
- * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/remote-state
- */
-static struct yang_data *
-bfdd_bfd_sessions_single_hop_stats_remote_state_get_elem(const char *xpath,
-							 const void *list_entry)
-{
-	const struct bfd_session *bs = list_entry;
-
-	return yang_data_new_enum(xpath, bs->ses_state);
-}
-
-/*
- * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/remote-diagnostic
- */
-static struct yang_data *
-bfdd_bfd_sessions_single_hop_stats_remote_diagnostic_get_elem(
-	const char *xpath, const void *list_entry)
-{
-	const struct bfd_session *bs = list_entry;
-
-	return yang_data_new_enum(xpath, bs->remote_diag);
-}
-
-/*
- * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/remote-multiplier
- */
-static struct yang_data *
-bfdd_bfd_sessions_single_hop_stats_remote_multiplier_get_elem(
-	const char *xpath, const void *list_entry)
-{
-	const struct bfd_session *bs = list_entry;
-
-	return yang_data_new_int8(xpath, bs->remote_detect_mult);
-}
-
-/*
- * XPath:
- * /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/negotiated-transmission-interval
- */
-static struct yang_data *
-bfdd_bfd_sessions_single_hop_stats_negotiated_transmission_interval_get_elem(
-	const char *xpath, const void *list_entry)
-{
-	const struct bfd_session *bs = list_entry;
-
-	return yang_data_new_uint32(xpath, bs->remote_timers.desired_min_tx);
-}
-
-/*
- * XPath:
- * /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/negotiated-receive-interval
- */
-static struct yang_data *
-bfdd_bfd_sessions_single_hop_stats_negotiated_receive_interval_get_elem(
-	const char *xpath, const void *list_entry)
-{
-	const struct bfd_session *bs = list_entry;
-
-	return yang_data_new_uint32(xpath, bs->remote_timers.required_min_rx);
-}
-
-/*
- * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/detection-mode
- */
-static struct yang_data *
-bfdd_bfd_sessions_single_hop_stats_detection_mode_get_elem(
-	const char *xpath, const void *list_entry)
-{
-	const struct bfd_session *bs = list_entry;
-	int detection_mode;
-
-	/*
-	 * Detection mode:
-	 *   1. Async with echo
-	 *   2. Async without echo
-	 *   3. Demand with echo
-	 *   4. Demand without echo
-	 *
-	 * TODO: support demand mode.
-	 */
-	if (BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_ECHO))
-		detection_mode = 1;
-	else
-		detection_mode = 2;
-
-	return yang_data_new_enum(xpath, detection_mode);
-}
-
-/*
- * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/last-down-time
- */
-static struct yang_data *
-bfdd_bfd_sessions_single_hop_stats_last_down_time_get_elem(
-	const char *xpath __attribute__((__unused__)),
-	const void *list_entry __attribute__((__unused__)))
-{
-	/*
-	 * TODO: implement me.
-	 *
-	 * No yang support for time elements yet.
-	 */
-	return NULL;
-}
-
-/*
- * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/last-up-time
- */
-static struct yang_data *
-bfdd_bfd_sessions_single_hop_stats_last_up_time_get_elem(
-	const char *xpath __attribute__((__unused__)),
-	const void *list_entry __attribute__((__unused__)))
-{
-	/*
-	 * TODO: implement me.
-	 *
-	 * No yang support for time elements yet.
-	 */
-	return NULL;
-}
-
-/*
- * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/session-down-count
- */
-static struct yang_data *
-bfdd_bfd_sessions_single_hop_stats_session_down_count_get_elem(
-	const char *xpath, const void *list_entry)
-{
-	const struct bfd_session *bs = list_entry;
-
-	return yang_data_new_uint64(xpath, bs->stats.session_down);
-}
-
-/*
- * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/session-up-count
- */
-static struct yang_data *
-bfdd_bfd_sessions_single_hop_stats_session_up_count_get_elem(
-	const char *xpath, const void *list_entry)
-{
-	const struct bfd_session *bs = list_entry;
-
-	return yang_data_new_uint64(xpath, bs->stats.session_up);
-}
-
-/*
- * XPath:
- * /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/control-packet-input-count
- */
-static struct yang_data *
-bfdd_bfd_sessions_single_hop_stats_control_packet_input_count_get_elem(
-	const char *xpath, const void *list_entry)
-{
-	const struct bfd_session *bs = list_entry;
-
-	return yang_data_new_uint64(xpath, bs->stats.rx_ctrl_pkt);
-}
-
-/*
- * XPath:
- * /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/control-packet-output-count
- */
-static struct yang_data *
-bfdd_bfd_sessions_single_hop_stats_control_packet_output_count_get_elem(
-	const char *xpath, const void *list_entry)
-{
-	const struct bfd_session *bs = list_entry;
-
-	return yang_data_new_uint64(xpath, bs->stats.tx_ctrl_pkt);
-}
-
-/*
- * XPath:
- * /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/negotiated-echo-transmission-interval
- */
-static struct yang_data *
-bfdd_bfd_sessions_single_hop_stats_negotiated_echo_transmission_interval_get_elem(
-	const char *xpath, const void *list_entry)
-{
-	const struct bfd_session *bs = list_entry;
-
-	return yang_data_new_uint32(xpath, bs->remote_timers.required_min_echo);
-}
-
-/*
- * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/echo-packet-input-count
- */
-static struct yang_data *
-bfdd_bfd_sessions_single_hop_stats_echo_packet_input_count_get_elem(
-	const char *xpath, const void *list_entry)
-{
-	const struct bfd_session *bs = list_entry;
-
-	return yang_data_new_uint64(xpath, bs->stats.rx_echo_pkt);
-}
-
-/*
- * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/stats/echo-packet-output-count
- */
-static struct yang_data *
-bfdd_bfd_sessions_single_hop_stats_echo_packet_output_count_get_elem(
-	const char *xpath, const void *list_entry)
-{
-	const struct bfd_session *bs = list_entry;
-
-	return yang_data_new_uint64(xpath, bs->stats.tx_echo_pkt);
-}
-
-/*
- * XPath: /frr-bfdd:bfdd/bfd/sessions/multi-hop
- */
-static int bfdd_bfd_sessions_multi_hop_create(enum nb_event event,
-					      const struct lyd_node *dnode,
-					      union nb_resource *resource)
-{
-	return bfd_session_create(event, dnode, resource, true);
-}
-
-static int bfdd_bfd_sessions_multi_hop_destroy(enum nb_event event,
-					       const struct lyd_node *dnode)
-{
-	return bfd_session_destroy(event, dnode, true);
-}
-
-static const void *
-bfdd_bfd_sessions_multi_hop_get_next(const void *parent_list_entry
-				     __attribute__((__unused__)),
-				     const void *list_entry)
-{
-	return bfd_session_next(list_entry, true);
-}
-
-static int bfdd_bfd_sessions_multi_hop_get_keys(const void *list_entry,
-						struct yang_list_keys *keys)
-{
-	const struct bfd_session *bs = list_entry;
-	char dstbuf[INET6_ADDRSTRLEN], srcbuf[INET6_ADDRSTRLEN];
-
-	inet_ntop(bs->key.family, &bs->key.peer, dstbuf, sizeof(dstbuf));
-	inet_ntop(bs->key.family, &bs->key.local, srcbuf, sizeof(srcbuf));
-
-	keys->num = 4;
-	strlcpy(keys->key[0], srcbuf, sizeof(keys->key[0]));
-	strlcpy(keys->key[1], dstbuf, sizeof(keys->key[1]));
-	strlcpy(keys->key[2], bs->key.ifname, sizeof(keys->key[2]));
-	strlcpy(keys->key[3], bs->key.vrfname, sizeof(keys->key[3]));
-
-	return NB_OK;
-}
-
-static const void *
-bfdd_bfd_sessions_multi_hop_lookup_entry(const void *parent_list_entry
-					 __attribute__((__unused__)),
-					 const struct yang_list_keys *keys)
-{
-	const char *source_addr = keys->key[0];
-	const char *dest_addr = keys->key[1];
-	const char *ifname = keys->key[2];
-	const char *vrf = keys->key[3];
-	struct sockaddr_any psa, lsa;
-	struct bfd_key bk;
-
-	strtosa(dest_addr, &psa);
-	strtosa(source_addr, &lsa);
-	gen_bfd_key(&bk, &psa, &lsa, true, ifname, vrf);
-
-	return bfd_key_lookup(bk);
-}
-
-/* clang-format off */
-const struct frr_yang_module_info frr_bfdd_info = {
-	.name = "frr-bfdd",
-	.nodes = {
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd",
-			.cbs = {
-				.create = bfdd_bfd_create,
-				.destroy = bfdd_bfd_destroy,
-				.cli_show = bfd_cli_show_header,
-				.cli_show_end = bfd_cli_show_header_end,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop",
-			.cbs = {
-				.create = bfdd_bfd_sessions_single_hop_create,
-				.destroy = bfdd_bfd_sessions_single_hop_destroy,
-				.get_next = bfdd_bfd_sessions_single_hop_get_next,
-				.get_keys = bfdd_bfd_sessions_single_hop_get_keys,
-				.lookup_entry = bfdd_bfd_sessions_single_hop_lookup_entry,
-				.cli_show = bfd_cli_show_single_hop_peer,
-				.cli_show_end = bfd_cli_show_peer_end,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/source-addr",
-			.cbs = {
-				.modify = bfdd_bfd_sessions_single_hop_source_addr_modify,
-				.destroy = bfdd_bfd_sessions_single_hop_source_addr_destroy,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/detection-multiplier",
-			.cbs = {
-				.modify = bfdd_bfd_sessions_single_hop_detection_multiplier_modify,
-				.cli_show = bfd_cli_show_mult,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/desired-transmission-interval",
-			.cbs = {
-				.modify = bfdd_bfd_sessions_single_hop_desired_transmission_interval_modify,
-				.cli_show = bfd_cli_show_tx,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/required-receive-interval",
-			.cbs = {
-				.modify = bfdd_bfd_sessions_single_hop_required_receive_interval_modify,
-				.cli_show = bfd_cli_show_rx,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/administrative-down",
-			.cbs = {
-				.modify = bfdd_bfd_sessions_single_hop_administrative_down_modify,
-				.cli_show = bfd_cli_show_shutdown,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/echo-mode",
-			.cbs = {
-				.modify = bfdd_bfd_sessions_single_hop_echo_mode_modify,
-				.cli_show = bfd_cli_show_echo,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/desired-echo-transmission-interval",
-			.cbs = {
-				.modify = bfdd_bfd_sessions_single_hop_desired_echo_transmission_interval_modify,
-				.cli_show = bfd_cli_show_echo_interval,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/local-discriminator",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_local_discriminator_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/local-state",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_local_state_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/local-diagnostic",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_local_diagnostic_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/local-multiplier",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_local_multiplier_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/remote-discriminator",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_remote_discriminator_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/remote-state",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_remote_state_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/remote-diagnostic",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_remote_diagnostic_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/remote-multiplier",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_remote_multiplier_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/negotiated-transmission-interval",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_negotiated_transmission_interval_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/negotiated-receive-interval",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_negotiated_receive_interval_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/detection-mode",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_detection_mode_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/last-down-time",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_last_down_time_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/last-up-time",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_last_up_time_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/session-down-count",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_session_down_count_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/session-up-count",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_session_up_count_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/control-packet-input-count",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_control_packet_input_count_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/control-packet-output-count",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_control_packet_output_count_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/negotiated-echo-transmission-interval",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_negotiated_echo_transmission_interval_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/echo-packet-input-count",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_echo_packet_input_count_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/stats/echo-packet-output-count",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_echo_packet_output_count_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop",
-			.cbs = {
-				.create = bfdd_bfd_sessions_multi_hop_create,
-				.destroy = bfdd_bfd_sessions_multi_hop_destroy,
-				.get_next = bfdd_bfd_sessions_multi_hop_get_next,
-				.get_keys = bfdd_bfd_sessions_multi_hop_get_keys,
-				.lookup_entry = bfdd_bfd_sessions_multi_hop_lookup_entry,
-				.cli_show = bfd_cli_show_multi_hop_peer,
-				.cli_show_end = bfd_cli_show_peer_end,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/detection-multiplier",
-			.cbs = {
-				.modify = bfdd_bfd_sessions_single_hop_detection_multiplier_modify,
-				.cli_show = bfd_cli_show_mult,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/desired-transmission-interval",
-			.cbs = {
-				.modify = bfdd_bfd_sessions_single_hop_desired_transmission_interval_modify,
-				.cli_show = bfd_cli_show_tx,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/required-receive-interval",
-			.cbs = {
-				.modify = bfdd_bfd_sessions_single_hop_required_receive_interval_modify,
-				.cli_show = bfd_cli_show_rx,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/administrative-down",
-			.cbs = {
-				.modify = bfdd_bfd_sessions_single_hop_administrative_down_modify,
-				.cli_show = bfd_cli_show_shutdown,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/local-discriminator",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_local_discriminator_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/local-state",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_local_state_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/local-diagnostic",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_local_diagnostic_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/local-multiplier",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_local_multiplier_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/remote-discriminator",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_remote_discriminator_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/remote-state",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_remote_state_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/remote-diagnostic",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_remote_diagnostic_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/remote-multiplier",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_remote_multiplier_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/negotiated-transmission-interval",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_negotiated_transmission_interval_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/negotiated-receive-interval",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_negotiated_receive_interval_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/detection-mode",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_detection_mode_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/last-down-time",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_last_down_time_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/last-up-time",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_last_up_time_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/session-down-count",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_session_down_count_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/session-up-count",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_session_up_count_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/control-packet-input-count",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_control_packet_input_count_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/control-packet-output-count",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_control_packet_output_count_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/negotiated-echo-transmission-interval",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_negotiated_echo_transmission_interval_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/echo-packet-input-count",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_echo_packet_input_count_get_elem,
-			}
-		},
-		{
-			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/stats/echo-packet-output-count",
-			.cbs = {
-				.get_elem = bfdd_bfd_sessions_single_hop_stats_echo_packet_output_count_get_elem,
-			}
-		},
-		{
-			.xpath = NULL,
-		},
-	}
-};
diff --git a/bfdd/subdir.am b/bfdd/subdir.am
index 5e3c3d476..ed1d3962b 100644
--- a/bfdd/subdir.am
+++ b/bfdd/subdir.am
@@ -13,7 +13,9 @@ endif
 
 bfdd_libbfd_a_SOURCES = \
 	bfdd/bfd.c \
-	bfdd/bfdd_northbound.c \
+	bfdd/bfdd_nb.c \
+	bfdd/bfdd_nb_config.c \
+	bfdd/bfdd_nb_state.c \
 	bfdd/bfdd_vty.c \
 	bfdd/bfdd_cli.c \
 	bfdd/bfd_packet.c \
@@ -32,6 +34,7 @@ bfdd/bfdd_cli.$(OBJEXT): bfdd/bfdd_cli_clippy.c
 
 noinst_HEADERS += \
 	bfdd/bfdctl.h \
+	bfdd/bfdd_nb.h \
 	bfdd/bfd.h \
 	# end