ospf6d: add json attributes to 'show ipv6 ospf6 neighbor'

Add the following attributes in each neighbor of the vty command:
'show ipv6 ospf6 neighbor json':
- nbrPriority : integer
- Role: DR, BDR, DROther, or PointToPoint
- nbrState : <state>/<Role> where:
   o Role is the above attribute
   o state is "None",    "Down",     "Attempt", "Init", "Twoway",
              "ExStart", "ExChange", "Loading", "Full"
- routerDeadIntervalTimerDueMsec: integer value otherwise "inactive"

Enter in a deprecation workflow for state and priority values, which
are replaced by nbrState.

Signed-off-by: Philippe Guibert <[email protected]>

ospf6d/ospf6_neighbor.c

@@ -890,7 +890,7 @@ static void ospf6_neighbor_show(struct vty *vty, struct ospf6_neighbor *on,
 	struct timeval res;
 	char nstate[17];
 	char deadtime[64];
-	long h, m, s;
+	long h, m, s, time_store;
 	json_object *json_route;
 
 	/* Router-ID (Name) */
@@ -940,10 +940,30 @@ static void ospf6_neighbor_show(struct vty *vty, struct ospf6_neighbor *on,
 		json_route = json_object_new_object();
 
 		json_object_string_add(json_route, "neighborId", router_id);
+#if CONFDATE > 20241129
+		CPP_NOTICE(
+			"Remove %s() JSON keys: state, priority", __func__)
+#endif
 		json_object_int_add(json_route, "priority", on->priority);
 		json_object_string_add(json_route, "deadTime", deadtime);
 		json_object_string_add(json_route, "state",
 				       ospf6_neighbor_state_str[on->state]);
+		json_object_int_add(json_route, "nbrPriority", on->priority);
+		json_object_string_add(json_route, "nbrState", nstate);
+		json_object_string_add(json_route, "Role",
+				       ospf6_neighbor_state_str[on->state]);
+		if (on->inactivity_timer) {
+			time_store =
+				monotime_until(&on->inactivity_timer->u.sands,
+					       NULL)
+				/ 1000LL;
+			json_object_int_add(json_route,
+					    "routerDeadIntervalTimerDueMsec",
+					    time_store);
+		} else
+			json_object_string_add(json_route,
+					       "routerDeadIntervalTimerDueMsec",
+					       "inactive");
 		json_object_string_add(json_route, "ifState", nstate);
 		json_object_string_add(json_route, "duration", duration);
 		json_object_string_add(json_route, "interfaceName",