Implement route_old and route_expired.

route.c

@@ -215,6 +215,18 @@ route_feasible(struct route *route)
     return update_feasible(route->src, route->seqno, route->refmetric);
 }
 
+int
+route_old(struct route *route)
+{
+    return route->time < now.tv_sec - route->hold_time * 7 / 8;
+}
+
+int
+route_expired(struct route *route)
+{
+    return route->time < now.tv_sec - route->hold_time;
+}
+
 int
 update_feasible(struct source *src,
                 unsigned short seqno, unsigned short refmetric)

route.h

@@ -47,6 +47,8 @@ void uninstall_route(struct route *route);
 void switch_route(struct route *old, struct route *new);
 void change_route_metric(struct route *route, unsigned newmetric);
 int route_feasible(struct route *route);
+int route_old(struct route *route);
+int route_expired(struct route *route);
 int update_feasible(struct source *src,
                     unsigned short seqno, unsigned short refmetric);
 struct route *find_best_route(const unsigned char *prefix, unsigned char plen,