ospf6d: Divide LSupdate to keep size small

Within OSPFv3 area, Disect Router LSA and
Intra-prefix LSA in order to keep LSA size Small.
Each LSA has unique Link State ID assigned.

Intra-Area-Prefix LSA:
Spread prefixes across multiple intra-area-prefix-LSAs.

Ticket:CM-18069
Testing Done:
Tested 92 ospf6 enabled (point-to-point) interfaces
between two routers.
92 adajancy comes up with Full Neighborship.
Validated 'show ipv6 ospf6 database router detail' &
'show ipv6 ospf6 database intra-prefix detail', each adv-router
has two distinct LSA of such catgory.

Signed-off-by: Chirag Shah <chirag@cumulusnetworks.com>

2 files changed, 119 insertions, 9 deletions

diff --git a/ospf6d/ospf6_area.c b/ospf6d/ospf6_area.c
index b12678624..6bbab46ad 100644
--- a/ospf6d/ospf6_area.c
+++ b/ospf6d/ospf6_area.c
@@ -234,6 +234,7 @@ struct ospf6_area *ospf6_area_create(u_int32_t area_id, struct ospf6 *o, int df)
 	oa->summary_prefix->scope = oa;
 	oa->summary_router = OSPF6_ROUTE_TABLE_CREATE(AREA, SUMMARY_ROUTERS);
 	oa->summary_router->scope = oa;
+	oa->router_lsa_size_limit = 1024 + 256;
 
 	/* set default options */
 	if (CHECK_FLAG(o->flag, OSPF6_STUB_ROUTER)) {
diff --git a/ospf6d/ospf6_intra.c b/ospf6d/ospf6_intra.c
index a2caeccb8..b5a0a9209 100644
--- a/ospf6d/ospf6_intra.c
+++ b/ospf6d/ospf6_intra.c
@@ -52,6 +52,7 @@ unsigned char conf_debug_ospf6_brouter = 0;
 u_int32_t conf_debug_ospf6_brouter_specific_router_id;
 u_int32_t conf_debug_ospf6_brouter_specific_area_id;
 
+#define MAX_LSA_PAYLOAD   (1024 + 256)
 /******************************/
 /* RFC2740 3.4.3.1 Router-LSA */
 /******************************/
@@ -214,8 +215,7 @@ int ospf6_router_lsa_originate(struct thread *thread)
 	ospf6_router_lsa_options_set(oa, router_lsa);
 
 	/* describe links for each interfaces */
-	lsdesc = (struct ospf6_router_lsdesc
-			  *)((caddr_t)router_lsa
+	lsdesc = (struct ospf6_router_lsdesc *)((caddr_t)router_lsa
 			     + sizeof(struct ospf6_router_lsa));
 
 	for (ALL_LIST_ELEMENTS(oa->if_list, node, nnode, oi)) {
@@ -248,6 +248,41 @@ int ospf6_router_lsa_originate(struct thread *thread)
 				return 0;
 			}
 
+			/* Fill LSA Header */
+			lsa_header->age = 0;
+			lsa_header->type = htons(OSPF6_LSTYPE_ROUTER);
+			lsa_header->id = htonl(link_state_id);
+			lsa_header->adv_router = oa->ospf6->router_id;
+			lsa_header->seqnum =
+				ospf6_new_ls_seqnum(lsa_header->type,
+						    lsa_header->id,
+				    lsa_header->adv_router, oa->lsdb);
+			lsa_header->length =
+				htons((caddr_t)lsdesc - (caddr_t)buffer);
+
+			/* LSA checksum */
+			ospf6_lsa_checksum(lsa_header);
+
+			/* create LSA */
+			lsa = ospf6_lsa_create(lsa_header);
+
+			/* Originate */
+			ospf6_lsa_originate_area(lsa, oa);
+
+			/* Reset Buffer to fill next Router LSA */
+			memset(buffer, 0, sizeof(buffer));
+			lsa_header = (struct ospf6_lsa_header *)buffer;
+			router_lsa =
+				(struct ospf6_router_lsa *)((caddr_t)lsa_header
+					    + sizeof(struct ospf6_lsa_header));
+
+			ospf6_router_lsa_options_set(oa, router_lsa);
+
+			/* describe links for each interfaces */
+			lsdesc = (struct ospf6_router_lsdesc *)
+				((caddr_t)router_lsa +
+				 sizeof(struct ospf6_router_lsa));
+
 			link_state_id++;
 		}
 
@@ -861,7 +896,7 @@ int ospf6_intra_prefix_lsa_originate_stub(struct thread *thread)
 
 	char buffer[OSPF6_MAX_LSASIZE];
 	struct ospf6_lsa_header *lsa_header;
-	struct ospf6_lsa *old, *lsa;
+	struct ospf6_lsa *old, *lsa, *old_next = NULL;
 
 	struct ospf6_intra_prefix_lsa *intra_prefix_lsa;
 	struct ospf6_interface *oi;
@@ -873,6 +908,7 @@ int ospf6_intra_prefix_lsa_originate_stub(struct thread *thread)
 	unsigned short prefix_num = 0;
 	char buf[PREFIX2STR_BUFFER];
 	struct ospf6_route_table *route_advertise;
+	int ls_id = 0;
 
 	oa = (struct ospf6_area *)THREAD_ARG(thread);
 	oa->thread_intra_prefix_lsa = NULL;
@@ -882,8 +918,22 @@ int ospf6_intra_prefix_lsa_originate_stub(struct thread *thread)
 				oa->ospf6->router_id, oa->lsdb);
 
 	if (!IS_AREA_ENABLED(oa)) {
-		if (old)
+		if (old) {
 			ospf6_lsa_purge(old);
+			/* find previous LSA */
+			old_next = ospf6_lsdb_lookup(
+					htons(OSPF6_LSTYPE_INTRA_PREFIX),
+					htonl(++ls_id),
+					oa->ospf6->router_id, oa->lsdb);
+
+			while (old_next) {
+				ospf6_lsa_purge(old_next);
+				old_next = ospf6_lsdb_lookup(
+					htons(OSPF6_LSTYPE_INTRA_PREFIX),
+					htonl(++ls_id),
+					oa->ospf6->router_id, oa->lsdb);
+			}
+		}
 		return 0;
 	}
 
@@ -895,8 +945,7 @@ int ospf6_intra_prefix_lsa_originate_stub(struct thread *thread)
 	/* prepare buffer */
 	memset(buffer, 0, sizeof(buffer));
 	lsa_header = (struct ospf6_lsa_header *)buffer;
-	intra_prefix_lsa = (struct ospf6_intra_prefix_lsa
-				    *)((caddr_t)lsa_header
+	intra_prefix_lsa = (struct ospf6_intra_prefix_lsa *)((caddr_t)lsa_header
 				       + sizeof(struct ospf6_lsa_header));
 
 	/* Fill Intra-Area-Prefix-LSA */
@@ -945,8 +994,23 @@ int ospf6_intra_prefix_lsa_originate_stub(struct thread *thread)
 	}
 
 	if (route_advertise->count == 0) {
-		if (old)
+		if (old) {
+			ls_id = 0;
 			ospf6_lsa_purge(old);
+			/* find previous LSA */
+			old_next = ospf6_lsdb_lookup(
+					htons(OSPF6_LSTYPE_INTRA_PREFIX),
+					htonl(++ls_id),
+					oa->ospf6->router_id, oa->lsdb);
+
+			while (old_next) {
+				ospf6_lsa_purge(old_next);
+				old_next = ospf6_lsdb_lookup(
+					htons(OSPF6_LSTYPE_INTRA_PREFIX),
+					htonl(++ls_id),
+					oa->ospf6->router_id, oa->lsdb);
+			}
+		}
 		ospf6_route_table_delete(route_advertise);
 		return 0;
 	}
@@ -957,13 +1021,58 @@ int ospf6_intra_prefix_lsa_originate_stub(struct thread *thread)
 				     + sizeof(struct ospf6_intra_prefix_lsa));
 	for (route = ospf6_route_head(route_advertise); route;
 	     route = ospf6_route_best_next(route)) {
+		if (((caddr_t)op - (caddr_t)lsa_header) > MAX_LSA_PAYLOAD) {
+
+			intra_prefix_lsa->prefix_num = htons(prefix_num);
+
+			/* Fill LSA Header */
+			lsa_header->age = 0;
+			lsa_header->type = htons(OSPF6_LSTYPE_INTRA_PREFIX);
+			lsa_header->id = htonl(ls_id++);
+			lsa_header->adv_router = oa->ospf6->router_id;
+			lsa_header->seqnum =
+				ospf6_new_ls_seqnum(lsa_header->type,
+						    lsa_header->id,
+						    lsa_header->adv_router,
+						    oa->lsdb);
+			lsa_header->length = htons((caddr_t)op -
+						   (caddr_t)lsa_header);
+
+			/* LSA checksum */
+			ospf6_lsa_checksum(lsa_header);
+
+			/* Create LSA */
+			lsa = ospf6_lsa_create(lsa_header);
+
+			/* Originate */
+			ospf6_lsa_originate_area(lsa, oa);
+
+			/* Prepare next buffer */
+			memset(buffer, 0, sizeof(buffer));
+			lsa_header = (struct ospf6_lsa_header *)buffer;
+			intra_prefix_lsa = (struct ospf6_intra_prefix_lsa *)
+					((caddr_t)lsa_header
+				       + sizeof(struct ospf6_lsa_header));
+
+			/* Fill Intra-Area-Prefix-LSA */
+			intra_prefix_lsa->ref_type = htons(OSPF6_LSTYPE_ROUTER);
+			intra_prefix_lsa->ref_id = htonl(0);
+			intra_prefix_lsa->ref_adv_router = oa->ospf6->router_id;
+
+			/* Put next set of prefixes to advertise */
+			prefix_num = 0;
+			op = (struct ospf6_prefix *)((caddr_t)intra_prefix_lsa
+				     + sizeof(struct ospf6_intra_prefix_lsa));
+		}
+
 		op->prefix_length = route->prefix.prefixlen;
 		op->prefix_options = route->path.prefix_options;
 		op->prefix_metric = htons(route->path.cost);
 		memcpy(OSPF6_PREFIX_BODY(op), &route->prefix.u.prefix6,
 		       OSPF6_PREFIX_SPACE(op->prefix_length));
-		op = OSPF6_PREFIX_NEXT(op);
 		prefix_num++;
+
+		op = OSPF6_PREFIX_NEXT(op);
 	}
 
 	ospf6_route_table_delete(route_advertise);
@@ -980,7 +1089,7 @@ int ospf6_intra_prefix_lsa_originate_stub(struct thread *thread)
 	/* Fill LSA Header */
 	lsa_header->age = 0;
 	lsa_header->type = htons(OSPF6_LSTYPE_INTRA_PREFIX);
-	lsa_header->id = htonl(0);
+	lsa_header->id = htonl(ls_id++);
 	lsa_header->adv_router = oa->ospf6->router_id;
 	lsa_header->seqnum =
 		ospf6_new_ls_seqnum(lsa_header->type, lsa_header->id,