Revert "bgpd: bgp_scan shouldn't queue up route_nodes with no routes for processing"

This reverts commit ff75b6c05bb9ca1b9c4c48f2231fd4cbfd393b17.

lib/table.c's route_common() can create a rn for a prefix that BGP has
never RXed.  For example here we RX 10.1.8.0/24 from neighbor 10.0.0.2,
notice how the 10.1.0.0/20 entry is created.  We would later assert on
this prefix because its info was NULL.

2016/06/16 23:37:21.418426 BGP: 10.0.0.2 rcvd UPDATE w/ attr: nexthop 10.0.0.2, origin i, localpref 100, metric 0, community 99:7, path
2016/06/16 23:37:21.418442 BGP: 10.0.0.2 rcvd UPDATE wlen 0 wpfx 0 attrlen 36 alen 4 apfx 1
2016/06/16 23:37:21.418458 BGP: bgp_node_create called
2016/06/16 23:37:21.418475 BGP: route_node_get called for 10.1.8.0/24, route_node_new 10.1.0.0/20, match (nil)
2016/06/16 23:37:21.418519 BGP: bgp_node_create called
2016/06/16 23:37:21.418536 BGP: route_node_get called for 10.1.8.0/24, route_node_new(2) 10.1.8.0/24, match 0x2013cd0
2016/06/16 23:37:21.418554 BGP: 10.0.0.2 rcvd 10.1.8.0/24

If rn->info is NULL then avoiding the group_announce_route() call in
bgp_proces_main() also feels risky as this code path generates WITHDRAWs
for prefixes that no longer have a bestpath which would be the case if
there are no paths.

diff --git a/bgpd/bgp_route.c b/bgpd/bgp_route.c
index a74d59ee32a2a2daaa6c54647ed9882ecf597b45..fff595d190df0a5b73b4da31abf7b88940f0c60e 100644 (file)
--- a/bgpd/bgp_route.c
+++ b/bgpd/bgp_route.c
@@ -1525,17 +1525,6 @@ bgp_best_selection (struct bgp *bgp, struct bgp_node *rn,
   char pfx_buf[PREFIX2STR_BUFFER];
   char path_buf[PATH_ADDPATH_STR_BUFFER];
 
-  result->old = result->new = NULL;
-  
-  if (rn->info == NULL)
-    {
-      char buf[PREFIX2STR_BUFFER];
-      zlog_warn ("%s: Called for route_node %s with no routing entries!",
-                 __func__,
-                 prefix2str (&(bgp_node_to_rnode (rn)->p), buf, sizeof(buf)));
-      return;
-    }
-  
   bgp_mp_list_init (&mp_list);
   do_mpath = (mpath_cfg->maxpaths_ebgp > 1 || mpath_cfg->maxpaths_ibgp > 1);
 
@@ -1924,19 +1913,6 @@ bgp_process (struct bgp *bgp, struct bgp_node *rn, afi_t afi, safi_t safi)
   if (CHECK_FLAG (rn->flags, BGP_NODE_PROCESS_SCHEDULED))
     return;
 
-  if (rn->info == NULL)
-    {
-      /* XXX: Perhaps remove before next release, after we've flushed out
-       * any obvious cases
-       */
-      assert (rn->info != NULL);
-      char buf[PREFIX2STR_BUFFER];
-      zlog_warn ("%s: Called for route_node %s with no routing entries!",
-                 __func__,
-                 prefix2str (&(bgp_node_to_rnode (rn)->p), buf, sizeof(buf)));
-      return;
-    }
-  
   if (bm->process_main_queue == NULL)
     bgp_process_queue_init ();