isisd: migrate BFD command to northbound

Specify the ISIS BFD command in the YANG model and implement the
northbound callbacks.

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

isisd/isis_cli.c

@@ -332,6 +332,39 @@ void cli_show_ip_isis_ipv6(struct vty *vty, struct lyd_node *dnode,
 		yang_dnode_get_string(dnode, "../area-tag"));
 }
 
+/*
+ * XPath: /frr-interface:lib/interface/frr-isisd:isis/bfd-monitoring
+ */
+DEFPY(isis_bfd,
+      isis_bfd_cmd,
+      "[no] isis bfd",
+      NO_STR
+      PROTO_HELP
+      "Enable BFD support\n")
+{
+	const struct lyd_node *dnode;
+
+	dnode = yang_dnode_get(vty->candidate_config->dnode,
+			       "%s/frr-isisd:isis", VTY_CURR_XPATH);
+	if (dnode == NULL)
+		return CMD_SUCCESS;
+
+	nb_cli_enqueue_change(vty, "./frr-isisd:isis/bfd-monitoring",
+			      NB_OP_MODIFY, no ? "false" : "true");
+
+	return nb_cli_apply_changes(vty, NULL);
+}
+
+void cli_show_ip_isis_bfd_monitoring(struct vty *vty, struct lyd_node *dnode,
+				     bool show_defaults)
+{
+	if (show_defaults == false)
+		vty_out(vty, " %s" PROTO_NAME " bfd\n",
+			yang_dnode_get_bool(dnode, NULL) ? "" : "no ");
+	else
+		vty_out(vty, " no " PROTO_NAME " bfd\n");
+}
+
 /*
  * XPath: /frr-isisd:isis/instance/area-address
  */
@@ -1949,6 +1982,7 @@ void isis_cli_init(void)
 	install_element(INTERFACE_NODE, &ip_router_isis_cmd);
 	install_element(INTERFACE_NODE, &ip6_router_isis_cmd);
 	install_element(INTERFACE_NODE, &no_ip_router_isis_cmd);
+	install_element(INTERFACE_NODE, &isis_bfd_cmd);
 
 	install_element(ISIS_NODE, &net_cmd);
 

isisd/isis_cli.h

@@ -27,6 +27,8 @@ void cli_show_ip_isis_ipv4(struct vty *vty, struct lyd_node *dnode,
 			   bool show_defaults);
 void cli_show_ip_isis_ipv6(struct vty *vty, struct lyd_node *dnode,
 			   bool show_defaults);
+void cli_show_ip_isis_bfd_monitoring(struct vty *vty, struct lyd_node *dnode,
+				     bool show_defaults);
 void cli_show_isis_area_address(struct vty *vty, struct lyd_node *dnode,
 				bool show_defaults);
 void cli_show_isis_is_type(struct vty *vty, struct lyd_node *dnode,

isisd/isis_northbound.c

@@ -25,6 +25,8 @@
 #include "libfrr.h"
 #include "linklist.h"
 #include "log.h"
+#include "lib/bfd.h"
+#include "isisd/isis_bfd.h"
 #include "isisd/isis_constants.h"
 #include "isisd/isis_common.h"
 #include "isisd/isis_flags.h"
@@ -1702,6 +1704,42 @@ static int lib_interface_isis_ipv6_routing_modify(enum nb_event event,
 	return NB_OK;
 }
 
+/*
+ * XPath: /frr-interface:lib/interface/frr-isisd:isis/bfd-monitoring
+ */
+static int lib_interface_isis_bfd_monitoring_modify(enum nb_event event,
+						    const struct lyd_node *dnode,
+						    union nb_resource *resource)
+{
+	struct isis_circuit *circuit;
+	bool bfd_monitoring;
+
+	if (event != NB_EV_APPLY)
+		return NB_OK;
+
+	circuit = nb_running_get_entry(dnode, NULL, true);
+	bfd_monitoring = yang_dnode_get_bool(dnode, NULL);
+
+	if (bfd_monitoring) {
+		/* Sanity check: BFD session is already registered. */
+		if (circuit->bfd_info != NULL)
+			return NB_OK;
+
+		isis_bfd_circuit_param_set(circuit, BFD_DEF_MIN_RX,
+					   BFD_DEF_MIN_TX, BFD_DEF_DETECT_MULT,
+					   true);
+	} else {
+		/* Sanity check: no BFD session was registered. */
+		if (circuit->bfd_info == NULL)
+			return NB_OK;
+
+		isis_bfd_circuit_cmd(circuit, ZEBRA_BFD_DEST_DEREGISTER);
+		bfd_info_free(&circuit->bfd_info);
+	}
+
+	return NB_OK;
+}
+
 /*
  * XPath: /frr-interface:lib/interface/frr-isisd:isis/csnp-interval/level-1
  */
@@ -3211,6 +3249,11 @@ const struct frr_yang_module_info frr_isisd_info = {
 				.modify = lib_interface_isis_ipv6_routing_modify,
 			},
 		},
+		{
+			.xpath = "/frr-interface:lib/interface/frr-isisd:isis/bfd-monitoring",
+			.cbs.modify = lib_interface_isis_bfd_monitoring_modify,
+			.cbs.cli_show = cli_show_ip_isis_bfd_monitoring,
+		},
 		{
 			.xpath = "/frr-interface:lib/interface/frr-isisd:isis/csnp-interval",
 			.cbs = {

yang/frr-isisd.yang

@@ -756,6 +756,12 @@ module frr-isisd {
           "IS-type of this circuit.";
       }
 
+      leaf bfd-monitoring {
+        type boolean;
+        default false;
+        description "Monitor IS-IS peers on this circuit.";
+      }
+
       container csnp-interval {
         description
           "Complete Sequence Number PDU (CSNP) generation interval.";