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>
This commit is contained in:
Dinesh Dutt 2013-08-24 07:54:24 +00:00 committed by David Lamparter
parent 2449fcd64a
commit ac58e143f7

View File

@ -258,6 +258,29 @@ ospf6_lsa_premature_aging (struct ospf6_lsa *lsa)
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);
}