Temporary integrated OSPF commit.

1 files changed, 110 insertions, 8 deletions

diff --git a/proto/ospf/topology.h b/proto/ospf/topology.h
index e4ea79f7..b34689e2 100644
--- a/proto/ospf/topology.h
+++ b/proto/ospf/topology.h
@@ -18,7 +18,7 @@ struct top_hash_entry
 				   in intra-area routing table calculation */
   struct top_hash_entry *next;	/* Next in hash chain */
   struct ospf_lsa_header lsa;
-  u16 lsa_type;			/* lsa.type processed and converted to common values */	
+  u16 lsa_type;			/* lsa.type processed and converted to common values (LSA_T_*) */	
   u16 init_age;			/* Initial value for lsa.age during inst_time */
   u32 domain;			/* Area ID for area-wide LSAs, Iface ID for link-wide LSAs */
   //  struct ospf_area *oa;
@@ -37,13 +37,115 @@ struct top_hash_entry
 #define OUTSPF 0
 #define CANDIDATE 1
 #define INSPF 2
-  u8 rtcalc;			/* LSA generated during RT calculation (LSA_RTCALC or LSA_STALE)*/
+  u8 mode;			/* LSA generated during RT calculation (LSA_RTCALC or LSA_STALE)*/
   u8 nhs_reuse;			/* Whether nhs nodes can be reused during merging.
 				   See a note in rt.c:merge_nexthops() */
 };
 
-#define LSA_RTCALC	1
-#define LSA_STALE	2
+
+/* Prevents ospf_hash_find() to ignore the entry, for p->lsrqh and p->lsrth */
+#define LSA_BODY_DUMMY ((void *) 1)
+
+/*
+ * LSA entry life cycle
+ *
+ * LSA entries are created by ospf_originate_lsa() (for locally originated LSAs)
+ * or ospf_install_lsa() (for LSAs received from neighbors). A regular (like
+ * newly originated) LSA entry has defined lsa_body nad lsa.age < %LSA_MAXAGE.
+ * When the LSA is requested to be flushed by ospf_flush_lsa(), the lsa.age is
+ * set to %LSA_MAXAGE and flooded. Flush process is finished asynchronously,
+ * when (at least) flooding is acknowledged by neighbors. This is detected in
+ * ospf_update_lsadb(), then ospf_clear_lsa() is called to free the LSA body but
+ * the LSA entry is kept. Such LSA does not formally exist, we keep an empty
+ * entry (until regular timeout) to know inst_time and lsa.sn in the case of
+ * later reorigination. After the timeout, LSA is removed by ospf_remove_lsa().
+ *
+ * When LSA origination is requested (by ospf_originate_lsa()). but it is not
+ * possible to do that immediately (because of MinLSInterval or because the
+ * sequence number is wrapping), The new LSA is scheduled for later origination
+ * in next_lsa_* fields of the LSA entry. The later origination is handled by
+ * ospf_originate_next_lsa() called from ospf_update_lsadb(). We can see that
+ * both real origination and final flush is asynchronous to ospf_originate_lsa()
+ * and ospf_flush_lsa().
+ *
+ * LSA entry therefore could be in three basic states:
+ * R - regular (lsa.age < %LSA_MAXAGE, lsa_body != NULL)
+ * F - flushing (lsa.age == %LSA_MAXAGE, lsa_body != NULL)
+ * E - empty (lsa.age == %LSA_MAXAGE, lsa_body == NULL)
+ *
+ * And these states are doubled based on whether the next LSA is scheduled
+ * (next_lsa_body != NULL, -n suffix) or not (next_lsa_body == NULL). We also
+ * use X for a state of non-existentce. We have this basic state graph
+ * (transitions from any state to R are omitted for clarity):
+ *
+ *  X --> R ---> F ---> E --> X
+ *        | \  / |      |
+ *        |  \/  |      |
+ *        |  /\  |      |
+ *        | /  \ |      |
+ *        Rn --> Fn --> En
+ *
+ * The transitions are:
+ *
+ * any state -> R		- new LSA origination requested and executed
+ * R -> Rn, F -> Fn, E -> En	- new LSA origination requested and postponed
+ * R -> Fn			- new LSA origination requested, seqnum wrapping
+ * Rn,Fn,En -> R		- postponed LSA finally originated
+ * R -> R			- LSA refresh done
+ * R -> Fn			- LSA refresh with seqnum wrapping
+ * R -> F, Rn -> Fn		- LSA age timeout
+ * R,Rn,Fn -> F, En -> E	- LSA flush requested
+ * F -> E, Fn -> En		- LSA flush done (acknowledged)
+ * E -> X			- LSA real age timeout (or immediate for received LSA)
+ *
+ * The 'origination requested' and 'flush requested' transitions are triggered
+ * and done by ospf_originate_lsa() and ospf_flush_lsa(), the rest is handled
+ * asynchronously by ospf_update_lsadb().
+ *
+ * The situation is significantly simpler for non-local (received) LSAs - there
+ * is no postponed origination and after flushing is done, LSAs are immediately
+ * removed, so it is just X -> R -> F -> X, or X -> F -> X (when MaxAge LSA is
+ * received).
+ *
+ * There are also some special cases related to handling of received unknown
+ * self-originated LSAs in ospf_advance_lsa():
+ * X -> F		- LSA is received and immediately flushed
+ * R,Rn -> Fn		- LSA with MaxSeqNo received and flushed, current LSA scheduled
+ */
+
+
+#define LSA_M_BASIC	0
+#define LSA_M_EXPORT	1
+#define LSA_M_RTCALC	2
+#define LSA_M_STALE	3
+
+/*
+ * LSA entry modes:
+ *
+ * LSA_M_BASIC - The LSA is explicitly originated using ospf_originate_lsa() and
+ * explicitly flushed using ospf_flush_lsa(). When the LSA is changed, the
+ * routing table calculation is scheduled. This is also the mode used for LSAs
+ * received from neighbors. Example: Router-LSAs, Network-LSAs.
+ *
+ * LSA_M_EXPORT - like LSA_M_BASIC, but the routing table calculation does not
+ * depend on the LSA. Therefore, the calculation is not scheduled when the LSA
+ * is changed. Example: AS-external-LSAs for exported routes.
+ *
+ * LSA_M_RTCALC - The LSA has to be requested using ospf_originate_lsa() during
+ * each routing table calculation, otherwise it is flushed automatically at the
+ * end of the calculation. The LSA is a result of the calculation and not a
+ * source for it. Therefore, the calculation is not scheduled when the LSA is
+ * changed. Example: Summary-LSAs.
+ *
+ * LSA_M_STALE - Temporary state for LSA_M_RTCALC that is not requested during
+ * the current routing table calculation.
+ *
+ *
+ * Note that we do not schedule the routing table calculation when the age of
+ * LSA_M_BASIC LSA is changed to MaxAge because of the sequence number wrapping,
+ * As it will be switched back to a regular one ASAP.
+ */
+
 
 struct top_graph
 {
@@ -61,6 +163,7 @@ struct top_graph
 struct ospf_new_lsa
 {
   u16 type;
+  u8  mode;
   u32 dom;
   u32 id;
   u16 opts;
@@ -69,9 +172,8 @@ struct ospf_new_lsa
   struct ort *nf;
 };
 
-struct top_graph *ospf_top_new(pool *);
-void ospf_top_free(struct top_graph *);
-void ospf_top_dump(struct top_graph *, struct proto *);
+struct top_graph *ospf_top_new(struct ospf_proto *p, pool *pool);
+void ospf_top_free(struct top_graph *f);
 
 struct top_hash_entry * ospf_install_lsa(struct ospf_proto *p, struct ospf_lsa_header *lsa, u32 type, u32 domain, void *body);
 struct top_hash_entry * ospf_originate_lsa(struct ospf_proto *p, struct ospf_new_lsa *lsa);
@@ -84,7 +186,7 @@ static inline void ospf_flush2_lsa(struct ospf_proto *p, struct top_hash_entry *
 
 void ospf_originate_sum_net_lsa(struct ospf_proto *p, struct ospf_area *oa, ort *nf, int metric);
 void ospf_originate_sum_rt_lsa(struct ospf_proto *p, struct ospf_area *oa, ort *nf, int metric, u32 options);
-void ospf_originate_ext_lsa(struct ospf_proto *p, struct ospf_area *oa, ort *nf, u8 rtcalc, u32 metric, u32 ebit, ip_addr fwaddr, u32 tag, int pbit);
+void ospf_originate_ext_lsa(struct ospf_proto *p, struct ospf_area *oa, ort *nf, u8 mode, u32 metric, u32 ebit, ip_addr fwaddr, u32 tag, int pbit);
 
 void ospf_rt_notify(struct proto *P, rtable *tbl, net *n, rte *new, rte *old, ea_list *attrs);
 void ospf_update_topology(struct ospf_proto *p);