bgpd: Try fix extcommunity resource allocation probs, particularly with 'set extcom..'
* Extended communities has some kind of resource allocation problem which
causes a double-free if the 'set extcommunity ...' command is used.
Try fix by properly interning extcommunities.
Also, more generally, make unintern functions take a double pointer
so they can NULL out callers references - a usefully defensive programming
pattern for functions which make refs invalid.
Sadly, this patch doesn't fix the problem entirely - crashes still
occur on session clear.
* bgp_ecommunity.h: (ecommunity_{free,unintern}) take double pointer
args.
* bgp_community.h: (community_unintern) ditto
* bgp_attr.h: (bgp_attr_intern) ditto
* bgp_aspath.h: (bgp_aspath.h) ditto
* (general) update all callers of above
* bgp_routemap.c: (route_set_ecommunity_{rt,soo}) intern the new extcom added
to the attr, and unintern any old one.
(route_set_ecommunity_{rt,soo}_compile) intern the extcom to be used
for the route-map set.
(route_set_ecommunity_*_free) unintern to match, instead of free
(route_set_ecommunity_soo) Do as _rt does and don't just leak
any pre-existing community, add to it (is additive right though?)
diff --git a/bgpd/bgp_community.c b/bgpd/bgp_community.c
index ae1d7a1..2ba45f6 100644
--- a/bgpd/bgp_community.c
+++ b/bgpd/bgp_community.c
@@ -321,21 +321,22 @@
/* Free community attribute. */
void
-community_unintern (struct community *com)
+community_unintern (struct community **com)
{
struct community *ret;
- if (com->refcnt)
- com->refcnt--;
+ if ((*com)->refcnt)
+ (*com)->refcnt--;
/* Pull off from hash. */
- if (com->refcnt == 0)
+ if ((*com)->refcnt == 0)
{
/* Community value com must exist in hash. */
- ret = (struct community *) hash_release (comhash, com);
+ ret = (struct community *) hash_release (comhash, *com);
assert (ret != NULL);
- community_free (com);
+ community_free (*com);
+ *com = NULL;
}
}