Nest: Recursive bgp routesold/bgp-recursive

Allow recursive routes if they reference a route with higher igp_metric.
Max depth set to 10.

1 files changed, 18 insertions, 5 deletions

diff --git a/nest/rt-table.c b/nest/rt-table.c
index c3ec0314..cb3e361c 100644
--- a/nest/rt-table.c
+++ b/nest/rt-table.c
@@ -2984,12 +2984,25 @@ rt_update_hostentry(rtable *tab, struct hostentry *he)
       rta *a = e->attrs;
       pxlen = n->n.addr->pxlen;
 
-      if (a->hostentry)
+      int MAX_REC = 10;
+      u32 prev_igp_metric = 0;
+      int i = 0;
+      for (struct hostentry *he = a->hostentry;
+	   he && he->src;
+	   i++, he = he->src->hostentry)
 	{
-	  /* Recursive route should not depend on another recursive route */
-	  log(L_WARN "Next hop address %I resolvable through recursive route for %N",
-	      he->addr, n->n.addr);
-	  goto done;
+	  log(L_WARN "Next hop address %I resolvable through recursive route for %N igp_metric %u %u",
+	      he->addr, n->n.addr, prev_igp_metric, he->igp_metric);
+
+	  if (prev_igp_metric >= he->igp_metric || i >= MAX_REC)
+	    {
+	      /* Recursive route should not depend on another recursive route */
+	      log(L_WARN "Next hop address %I resolvable through deep recursive route for %N",
+		  he->addr, n->n.addr);
+	      goto done;
+	    }
+
+	  prev_igp_metric = he->igp_metric;
 	}
 
       if (a->dest == RTD_UNICAST)