Route sources have an explicit owner

This commit prevents use-after-free of routes belonging to protocols
which have been already destroyed, delaying also all the protocols'
shutdown until all of their routes have been finally propagated through
all the pipes down to the appropriate exports.

The use-after-free was somehow hypothetic yet theoretically possible in
rare conditions, when one BGP protocol authors a lot of routes and the
user deletes that protocol by reconfiguring in the same time as next hop
update is requested, causing rte_better() to be called on a
not-yet-pruned network prefix while the owner protocol has been already
freed.

In parallel execution environments, this would happen an inter-thread
use-after-free, causing possible heisenbugs or other nasty problems.

1 files changed, 2 insertions, 2 deletions

diff --git a/proto/mrt/mrt.c b/proto/mrt/mrt.c
index 5da3c7c6..9d78438d 100644
--- a/proto/mrt/mrt.c
+++ b/proto/mrt/mrt.c
@@ -472,9 +472,9 @@ mrt_rib_table_entry(struct mrt_table_dump_state *s, rte *r)
 
 #ifdef CONFIG_BGP
   /* Find peer index */
-  if (r->src->proto->proto == &proto_bgp)
+  struct bgp_proto *p = bgp_rte_proto(r);
+  if (p)
   {
-    struct bgp_proto *p = (void *) r->src->proto;
     struct mrt_peer_entry *n =
       HASH_FIND(s->peer_hash, PEER, p->remote_id, p->remote_as, p->remote_ip);