ospf6d: remove older version of LSA from neigbor retx list before prematurely aging it.
See comment in code for very detailed issue and fix.
Signed-off-by: Dinesh G Dutt <ddutt at cumulusnetworks.com>
Reviewed-by: Scott Feldman <sfeldma at cumulusnetworks.com>
Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
diff --git a/ospf6d/ospf6_lsa.c b/ospf6d/ospf6_lsa.c
index 7dbd303..1839880 100644
--- a/ospf6d/ospf6_lsa.c
+++ b/ospf6d/ospf6_lsa.c
@@ -258,6 +258,29 @@
THREAD_OFF (lsa->expire);
THREAD_OFF (lsa->refresh);
+ /*
+ * We clear the LSA from the neighbor retx lists now because it
+ * will not get deleted later. Essentially, changing the age to
+ * MaxAge will prevent this LSA from being matched with its
+ * existing entries in the retx list thereby causing those entries
+ * to be silently replaced with its MaxAged version, but with ever
+ * increasing retx count causing this LSA to remain forever and
+ * for the MaxAge remover thread to be called forever too.
+ *
+ * The reason the previous entry silently disappears is that when
+ * entry is added to a neighbor's retx list, it replaces the existing
+ * entry. But since the ospf6_lsdb_add() routine is generic and not aware
+ * of the special semantics of retx count, the retx count is not
+ * decremented when its replaced. Attempting to add the incr and decr
+ * retx count routines as the hook_add and hook_remove for the retx lists
+ * have a problem because the hook_remove routine is called for MaxAge
+ * entries (as will be the case in a traditional LSDB, unlike in this case
+ * where an LSDB is used as an efficient tree structure to store all kinds
+ * of data) that are added instead of calling the hook_add routine.
+ */
+
+ ospf6_flood_clear (lsa);
+
lsa->header->age = htons (OSPF_LSA_MAXAGE);
thread_execute (master, ospf6_lsa_expire, lsa, 0);
}