ospf6d: Support for nssa in ospfv3

The following is implemented.
1. Configuring area as NSSA.
2. Generating Type 7 LSA.
3. Conversion of Type 7 to Type 5 ( Default Behavior).
4. NSSA ABR selection.

Reviewed-by: Rafael Zalamena <rzalamena@opensourcerouting.org>
Co-authored-by: Kaushik <kaushiknath.null@gmail.com>
Co-authored-by: Soman K.S <somanks@gmail.com>
Signed-off-by: Kaushik <kaushiknath.null@gmail.com>

1 files changed, 185 insertions, 0 deletions

diff --git a/ospf6d/ospf6_spf.c b/ospf6d/ospf6_spf.c
index 7652d71c59..1d32844fec 100644
--- a/ospf6d/ospf6_spf.c
+++ b/ospf6d/ospf6_spf.c
@@ -37,11 +37,13 @@
 #include "ospf6_area.h"
 #include "ospf6_proto.h"
 #include "ospf6_abr.h"
+#include "ospf6_asbr.h"
 #include "ospf6_spf.h"
 #include "ospf6_intra.h"
 #include "ospf6_interface.h"
 #include "ospf6d.h"
 #include "ospf6_abr.h"
+#include "ospf6_nssa.h"
 
 DEFINE_MTYPE_STATIC(OSPF6D, OSPF6_VERTEX, "OSPF6 vertex");
 
@@ -640,6 +642,9 @@ static int ospf6_spf_calculation_thread(struct thread *t)
 		areas_processed++;
 	}
 
+	/* External LSA calculation */
+	ospf6_ase_calculate_timer_add(ospf6);
+
 	if (ospf6_is_router_abr(ospf6))
 		ospf6_abr_defaults_to_stub(ospf6);
 
@@ -1105,3 +1110,183 @@ void ospf6_remove_temp_router_lsa(struct ospf6_area *area)
 		ospf6_lsdb_remove(lsa, area->temp_router_lsa_lsdb);
 	}
 }
+
+int ospf6_ase_calculate_route(struct ospf6 *ospf6, struct ospf6_lsa *lsa,
+			      struct ospf6_area *area)
+{
+	struct ospf6_route *route, *old;
+	struct ospf6_as_external_lsa *external;
+	struct prefix prefix;
+	void (*hook_add)(struct ospf6_route *) = NULL;
+	void (*hook_remove)(struct ospf6_route *) = NULL;
+
+	assert(lsa);
+
+	if (IS_OSPF6_DEBUG_SPF(PROCESS))
+		zlog_debug("%s :  start", __func__);
+
+	if (ntohs(lsa->header->type) == OSPF6_LSTYPE_TYPE_7)
+		if (IS_OSPF6_DEBUG_SPF(PROCESS))
+			zlog_debug("%s: Processing Type-7", __func__);
+
+	/* Stay away from any Local Translated Type-7 LSAs */
+	if (CHECK_FLAG(lsa->flag, OSPF6_LSA_LOCAL_XLT)) {
+		if (IS_OSPF6_DEBUG_SPF(PROCESS))
+			zlog_debug("%s: Rejecting Local translated LSA",
+				   __func__);
+		return 0;
+	}
+
+	external = (struct ospf6_as_external_lsa *)OSPF6_LSA_HEADER_END(
+		lsa->header);
+	prefix.family = AF_INET6;
+	prefix.prefixlen = external->prefix.prefix_length;
+	ospf6_prefix_in6_addr(&prefix.u.prefix6, external, &external->prefix);
+
+	if (ntohs(lsa->header->type) == OSPF6_LSTYPE_AS_EXTERNAL) {
+		hook_add = ospf6->route_table->hook_add;
+		hook_remove = ospf6->route_table->hook_remove;
+		ospf6->route_table->hook_add = NULL;
+		ospf6->route_table->hook_remove = NULL;
+
+		old = ospf6_route_lookup(&prefix, ospf6->route_table);
+		if (old) {
+			if (IS_OSPF6_DEBUG_SPF(PROCESS))
+				zlog_debug("%s : remove external route %pFX",
+					   __func__, &prefix);
+			old->flag = OSPF6_ROUTE_REMOVE;
+		}
+
+		if (!OSPF6_LSA_IS_MAXAGE(lsa))
+			ospf6_asbr_lsa_add(lsa);
+
+		ospf6->route_table->hook_add = hook_add;
+		ospf6->route_table->hook_remove = hook_remove;
+
+		route = ospf6_route_lookup(&prefix, ospf6->route_table);
+		if (route == NULL) {
+			if (IS_OSPF6_DEBUG_SPF(PROCESS))
+				zlog_debug("%s : no external route %pFX",
+					   __func__, &prefix);
+			return 0;
+		}
+
+		if (CHECK_FLAG(route->flag, OSPF6_ROUTE_REMOVE)
+		    && (CHECK_FLAG(route->flag, OSPF6_ROUTE_ADD)
+			|| (old == route))) {
+			UNSET_FLAG(route->flag, OSPF6_ROUTE_REMOVE);
+			UNSET_FLAG(route->flag, OSPF6_ROUTE_ADD);
+		}
+
+		if (CHECK_FLAG(route->flag, OSPF6_ROUTE_REMOVE))
+			ospf6_route_remove(route, ospf6->route_table);
+		else if (CHECK_FLAG(route->flag, OSPF6_ROUTE_ADD)
+			 || CHECK_FLAG(route->flag, OSPF6_ROUTE_CHANGE)) {
+			if (hook_add) {
+				if (IS_OSPF6_DEBUG_SPF(PROCESS))
+					zlog_debug(
+						"%s: add external route %pFX",
+						__func__, &prefix);
+				(*hook_add)(route);
+			}
+			route->flag = 0;
+		}
+	} else if (ntohs(lsa->header->type) == OSPF6_LSTYPE_TYPE_7) {
+		hook_add = area->route_table->hook_add;
+		hook_remove = area->route_table->hook_remove;
+		area->route_table->hook_add = NULL;
+		area->route_table->hook_remove = NULL;
+
+		old = ospf6_route_lookup(&prefix, area->route_table);
+		if (old) {
+			if (IS_OSPF6_DEBUG_SPF(PROCESS))
+				zlog_debug(
+					"%s: set remove flag nssa route %pFX, area %s",
+					__func__, &prefix, area->name);
+			old->flag = OSPF6_ROUTE_REMOVE;
+		}
+
+		if (!OSPF6_LSA_IS_MAXAGE(lsa))
+			ospf6_asbr_lsa_add(lsa);
+
+		area->route_table->hook_add = hook_add;
+		area->route_table->hook_remove = hook_remove;
+
+		route = ospf6_route_lookup(&prefix, area->route_table);
+		if (route == NULL) {
+			if (IS_OSPF6_DEBUG_SPF(PROCESS))
+				zlog_debug("%s : no route %pFX, area %s",
+					   __func__, &prefix, area->name);
+			return 0;
+		}
+
+		if (CHECK_FLAG(route->flag, OSPF6_ROUTE_REMOVE)
+		    && (CHECK_FLAG(route->flag, OSPF6_ROUTE_ADD)
+			|| (old == route))) {
+			UNSET_FLAG(route->flag, OSPF6_ROUTE_REMOVE);
+			UNSET_FLAG(route->flag, OSPF6_ROUTE_ADD);
+		}
+
+		if (CHECK_FLAG(route->flag, OSPF6_ROUTE_REMOVE)) {
+			if (IS_OSPF6_DEBUG_SPF(PROCESS))
+				zlog_debug("%s : remove route %pFX, area %s",
+					   __func__, &prefix, area->name);
+			ospf6_route_remove(route, area->route_table);
+		} else if (CHECK_FLAG(route->flag, OSPF6_ROUTE_ADD)
+			   || CHECK_FLAG(route->flag, OSPF6_ROUTE_CHANGE)) {
+			if (hook_add) {
+				if (IS_OSPF6_DEBUG_SPF(PROCESS))
+					zlog_debug(
+						"%s: add nssa route %pFX, area %s",
+						__func__, &prefix, area->name);
+				(*hook_add)(route);
+			}
+			ospf6_abr_check_translate_nssa(area, lsa);
+			route->flag = 0;
+		}
+	}
+	return 0;
+}
+
+static int ospf6_ase_calculate_timer(struct thread *t)
+{
+	struct ospf6 *ospf6;
+	struct ospf6_lsa *lsa;
+	struct listnode *node, *nnode;
+	struct ospf6_area *area;
+	uint16_t type;
+
+	ospf6 = THREAD_ARG(t);
+	ospf6->t_ase_calc = NULL;
+
+	/* Calculate external route for each AS-external-LSA */
+	type = htons(OSPF6_LSTYPE_AS_EXTERNAL);
+	for (ALL_LSDB_TYPED(ospf6->lsdb, type, lsa))
+		ospf6_ase_calculate_route(ospf6, lsa, NULL);
+
+	/*  This version simple adds to the table all NSSA areas  */
+	if (ospf6->anyNSSA) {
+		for (ALL_LIST_ELEMENTS(ospf6->area_list, node, nnode, area)) {
+			if (IS_OSPF6_DEBUG_SPF(PROCESS))
+				zlog_debug("%s : looking at area %s", __func__,
+					   area->name);
+
+			if (IS_OSPF6_DEBUG_SPF(PROCESS)) {
+				type = htons(OSPF6_LSTYPE_TYPE_7);
+				for (ALL_LSDB_TYPED(area->lsdb, type, lsa))
+					ospf6_ase_calculate_route(ospf6, lsa,
+								  area);
+			}
+		}
+	}
+	return 0;
+}
+
+void ospf6_ase_calculate_timer_add(struct ospf6 *ospf6)
+{
+	if (ospf6 == NULL)
+		return;
+
+	thread_add_timer(master, ospf6_ase_calculate_timer, ospf6,
+			 OSPF6_ASE_CALC_INTERVAL, &ospf6->t_ase_calc);
+}