Implements router advertisements activated by received routes.

The RAdv protocol could be configured to change its behavior based on
availability of routes, e.g., do not announce router lifetime when a
default route is not available.

2 files changed, 40 insertions, 4 deletions

diff --git a/nest/route.h b/nest/route.h
index 177baa38..8fd01a66 100644
--- a/nest/route.h
+++ b/nest/route.h
@@ -235,6 +235,12 @@ static inline int rte_is_filtered(rte *r) { return !!(r->flags & REF_FILTERED);
 #define RA_ACCEPTED	2		/* Announcement of first accepted route */
 #define RA_ANY		3		/* Announcement of any route change */
 
+/* Return value of import_control() callback */
+#define RIC_ACCEPT	1		/* Accepted by protocol */
+#define RIC_PROCESS	0		/* Process it through import filter */
+#define RIC_REJECT	-1		/* Rejected by protocol */
+#define RIC_DROP	-2		/* Silently dropped by protocol */
+
 struct config;
 
 void rt_init(void);
@@ -250,6 +256,7 @@ rte *rte_get_temp(struct rta *);
 void rte_update2(struct announce_hook *ah, net *net, rte *new, struct proto *src);
 static inline void rte_update(rtable *tab, net *net, struct proto *p, struct proto *src, rte *new) { rte_update2(p->main_ahook, net, new, src); }
 void rte_discard(rtable *tab, rte *old);
+int rt_examine(rtable *t, ip_addr prefix, int pxlen, struct proto *p, struct filter *filter);
 void rte_dump(rte *);
 void rte_free(rte *);
 rte *rte_do_cow(rte *);
diff --git a/nest/rt-table.c b/nest/rt-table.c
index 99175448..75bfa6ba 100644
--- a/nest/rt-table.c
+++ b/nest/rt-table.c
@@ -213,7 +213,8 @@ export_filter(struct announce_hook *ah, rte *rt0, rte **rt_free, ea_list **tmpa,
 	goto reject;
 
       stats->exp_updates_rejected++;
-      rte_trace_out(D_FILTERS, p, rt, "rejected by protocol");
+      if (v == RIC_REJECT)
+	rte_trace_out(D_FILTERS, p, rt, "rejected by protocol");
       goto reject;
     }
   if (v > 0)
@@ -1042,6 +1043,34 @@ rte_discard(rtable *t, rte *old)	/* Non-filtered route deletion, used during gar
   rte_update_unlock();
 }
 
+/* Check rtable for best route to given net whether it would be exported do p */
+int
+rt_examine(rtable *t, ip_addr prefix, int pxlen, struct proto *p, struct filter *filter)
+{
+  net *n = net_find(t, prefix, pxlen);
+  rte *rt = n ? n->routes : NULL;
+
+  if (!rte_is_valid(rt))
+    return 0;
+
+  rte_update_lock();
+
+  /* Rest is stripped down export_filter() */
+  struct proto *src = rt->attrs->proto;
+  ea_list *tmpa = src->make_tmp_attrs ? src->make_tmp_attrs(rt, rte_update_pool) : NULL;
+  int v = p->import_control ? p->import_control(p, &rt, &tmpa, rte_update_pool) : 0;
+  if (v == RIC_PROCESS)
+    v = (f_run(filter, &rt, &tmpa, rte_update_pool, FF_FORCE_TMPATTR) <= F_ACCEPT);
+
+   /* Discard temporary rte */
+  if (rt != n->routes)
+    rte_free(rt);
+
+  rte_update_unlock();
+
+  return v > 0;
+}
+
 /**
  * rte_dump - dump a route
  * @e: &rte to be dumped
@@ -2081,7 +2110,7 @@ rt_show_net(struct cli *c, net *n, struct rt_show_data *d)
       ee = e;
       rte_update_lock();		/* We use the update buffer for filtering */
       tmpa = p0->make_tmp_attrs ? p0->make_tmp_attrs(e, rte_update_pool) : NULL;
-      ok = (d->filter == FILTER_ACCEPT || f_run(d->filter, &e, &tmpa, rte_update_pool, FF_FORCE_TMPATTR) <= F_ACCEPT);
+      ok = f_run(d->filter, &e, &tmpa, rte_update_pool, FF_FORCE_TMPATTR) <= F_ACCEPT;
       if (p2 && p2 != p0) ok = 0;
       if (ok && d->export_mode)
 	{
@@ -2095,8 +2124,8 @@ rt_show_net(struct cli *c, net *n, struct rt_show_data *d)
 		 'configure soft' command may change the export filter
 		 and do not update routes */
 
-	      if ((a = proto_find_announce_hook(p1, d->table)) && ((a->out_filter == FILTER_REJECT) ||
-		  (a->out_filter && f_run(a->out_filter, &e, &tmpa, rte_update_pool, FF_FORCE_TMPATTR) > F_ACCEPT)))
+	      if ((a = proto_find_announce_hook(p1, d->table)) && 
+		  (f_run(a->out_filter, &e, &tmpa, rte_update_pool, FF_FORCE_TMPATTR) > F_ACCEPT))
 		ok = 0;
 	    }
 	}