Flush blackhole xroutes faster.

babel.c

@@ -754,7 +754,9 @@ expire_routes(void)
     i = 0;
     while(i < numxroutes) {
         struct xroute *xroute = &xroutes[i];
-        if(xroute->time < now.tv_sec - xroute_gc_delay) {
+        if(xroute->time < now.tv_sec - xroute_gc_delay ||
+           (xroute->cost >= INFINITY &&
+            xroute->time < now.tv_sec - xroute_hold_delay)) {
             flush_xroute(xroute);
             continue;
         }

xroute.c

@@ -40,6 +40,7 @@ struct xroute myxroutes[MAXMYXROUTES];
 int nummyxroutes = 0;
 
 int xroute_gc_delay = 180;
+int xroute_hold_delay = 45;
 
 static struct xroute *
 find_installed_xroute(unsigned char *prefix, unsigned short plen)

xroute.h

@@ -39,6 +39,7 @@ extern struct xroute myxroutes[MAXMYXROUTES];
 extern int nummyxroutes;
 
 extern int xroute_gc_delay;
+extern int xroute_hold_delay;
 
 void install_xroute(struct xroute *xroute);
 void uninstall_xroute(struct xroute *xroute);