[ospfd] draft-ogier-ospf-dbex-opt DB-exchange optimisation
2006-08-03 Paul Jakma <paul.jakma@sun.com>
* ospf_packet.c: (ospf_make_db_desc) Implement
draft-ogier-ospf-dbex-opt DB-exchange optimisation.
diff --git a/ospfd/ChangeLog b/ospfd/ChangeLog
index 193f0de..05f96ac 100644
--- a/ospfd/ChangeLog
+++ b/ospfd/ChangeLog
@@ -15,6 +15,7 @@
before deciding whether both sides are done, avoids a
needless round of empty DD packet exchanges at the end of
Exchange, hence speeding up ExchangeDone.
+ Implement draft-ogier-ospf-dbex-opt DB-exchange optimisation.
(ospf_db_desc) use UNSET_FLAG macro.
2006-07-27 Andrew J. Schorr <ajschorr@alumni.princeton.edu>
diff --git a/ospfd/ospf_packet.c b/ospfd/ospf_packet.c
index 74caaa7..6449e63 100644
--- a/ospfd/ospf_packet.c
+++ b/ospfd/ospf_packet.c
@@ -1035,20 +1035,40 @@
/* Lookup received LSA, then add LS request list. */
find = ospf_lsa_lookup_by_header (oi->area, lsah);
- if (!find || ospf_lsa_more_recent (find, new) < 0)
- {
- ospf_ls_request_add (nbr, new);
- ospf_lsa_discard (new);
- }
- else
- {
- /* Received LSA is not recent. */
- if (IS_DEBUG_OSPF_EVENT)
- zlog_debug ("Packet [DD:RECV]: LSA received Type %d, "
- "ID %s is not recent.", lsah->type, inet_ntoa (lsah->id));
- ospf_lsa_discard (new);
- continue;
- }
+
+ /* ospf_lsa_more_recent is fine with NULL pointers */
+ switch (ospf_lsa_more_recent (find, new))
+ {
+ case -1:
+ /* Neighbour has a more recent LSA, we must request it */
+ ospf_ls_request_add (nbr, new);
+ case 0:
+ /* If we have a copy of this LSA, it's either less recent
+ * and we're requesting it from neighbour (the case above), or
+ * it's as recent and we both have same copy (this case).
+ *
+ * In neither of these two cases is there any point in
+ * describing our copy of the LSA to the neighbour in a
+ * DB-Summary packet, if we're still intending to do so.
+ *
+ * See: draft-ogier-ospf-dbex-opt-00.txt, describing the
+ * backward compatible optimisation to OSPF DB Exchange /
+ * DB Description process implemented here.
+ */
+ if (find)
+ ospf_lsdb_delete (&nbr->db_sum, find);
+ ospf_lsa_discard (new);
+ break;
+ default:
+ /* We have the more recent copy, nothing specific to do:
+ * - no need to request neighbours stale copy
+ * - must leave DB summary list copy alone
+ */
+ if (IS_DEBUG_OSPF_EVENT)
+ zlog_debug ("Packet [DD:RECV]: LSA received Type %d, "
+ "ID %s is not recent.", lsah->type, inet_ntoa (lsah->id));
+ ospf_lsa_discard (new);
+ }
}
/* Master */