Adding upstream version 9.1.upstream/9.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 4271 insertions, 0 deletions

diff --git a/ospfd/ospf_lsa.c b/ospfd/ospf_lsa.c
new file mode 100644
index 0000000..e47f832
--- /dev/null
+++ b/ospfd/ospf_lsa.c
@@ -0,0 +1,4271 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * OSPF Link State Advertisement
+ * Copyright (C) 1999, 2000 Toshiaki Takada
+ */
+
+#include <zebra.h>
+
+#include "monotime.h"
+#include "linklist.h"
+#include "prefix.h"
+#include "if.h"
+#include "table.h"
+#include "memory.h"
+#include "stream.h"
+#include "log.h"
+#include "frrevent.h"
+#include "hash.h"
+#include "sockunion.h" /* for inet_aton() */
+#include "checksum.h"
+#include "network.h"
+
+#include "ospfd/ospfd.h"
+#include "ospfd/ospf_interface.h"
+#include "ospfd/ospf_ism.h"
+#include "ospfd/ospf_asbr.h"
+#include "ospfd/ospf_lsa.h"
+#include "ospfd/ospf_lsdb.h"
+#include "ospfd/ospf_neighbor.h"
+#include "ospfd/ospf_nsm.h"
+#include "ospfd/ospf_flood.h"
+#include "ospfd/ospf_packet.h"
+#include "ospfd/ospf_spf.h"
+#include "ospfd/ospf_dump.h"
+#include "ospfd/ospf_route.h"
+#include "ospfd/ospf_ase.h"
+#include "ospfd/ospf_zebra.h"
+#include "ospfd/ospf_abr.h"
+#include "ospfd/ospf_errors.h"
+
+static struct ospf_lsa *ospf_handle_summarylsa_lsId_chg(struct ospf_area *area,
+							struct prefix_ipv4 *p,
+							uint8_t type,
+							uint32_t metric,
+							struct in_addr old_id);
+static struct ospf_lsa *
+ospf_summary_lsa_prepare_and_flood(struct prefix_ipv4 *p, uint32_t metric,
+				   struct ospf_area *area, struct in_addr id);
+static struct ospf_lsa *ospf_summary_lsa_refresh(struct ospf *ospf,
+						 struct ospf_lsa *lsa);
+static struct ospf_lsa *
+ospf_asbr_summary_lsa_prepare_and_flood(struct prefix_ipv4 *p, uint32_t metric,
+					struct ospf_area *area,
+					struct in_addr id);
+static struct ospf_lsa *ospf_summary_asbr_lsa_refresh(struct ospf *ospf,
+						      struct ospf_lsa *lsa);
+static struct ospf_lsa *ospf_handle_exnl_lsa_lsId_chg(struct ospf *ospf,
+						      struct external_info *ei,
+						      struct in_addr id);
+static struct ospf_lsa *
+ospf_exnl_lsa_prepare_and_flood(struct ospf *ospf, struct external_info *ei,
+				struct in_addr id);
+
+uint32_t get_metric(uint8_t *metric)
+{
+	uint32_t m;
+	m = metric[0];
+	m = (m << 8) + metric[1];
+	m = (m << 8) + metric[2];
+	return m;
+}
+
+/** @brief The Function checks self generated DoNotAge.
+ *  @param lsa pointer.
+ *  @return true or false.
+ */
+bool ospf_check_dna_lsa(const struct ospf_lsa *lsa)
+{
+	return ((IS_LSA_SELF(lsa) && CHECK_FLAG(lsa->data->ls_age, DO_NOT_AGE))
+			? true
+			: false);
+}
+
+struct timeval int2tv(int a)
+{
+	struct timeval ret;
+
+	ret.tv_sec = a;
+	ret.tv_usec = 0;
+
+	return ret;
+}
+
+struct timeval msec2tv(int a)
+{
+	struct timeval ret;
+
+	ret.tv_sec = a / 1000;
+	ret.tv_usec = (a % 1000) * 1000;
+
+	return ret;
+}
+
+int ospf_lsa_refresh_delay(struct ospf_lsa *lsa)
+{
+	struct timeval delta;
+	int delay = 0;
+
+	if (monotime_since(&lsa->tv_orig, &delta)
+	    < OSPF_MIN_LS_INTERVAL * 1000LL) {
+		struct timeval minv = msec2tv(OSPF_MIN_LS_INTERVAL);
+		timersub(&minv, &delta, &minv);
+
+		/* TBD: remove padding to full sec, return timeval instead */
+		delay = minv.tv_sec + !!minv.tv_usec;
+
+		if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+			zlog_debug(
+				"LSA[Type%d:%pI4]: Refresh timer delay %d seconds",
+				lsa->data->type, &lsa->data->id,
+				delay);
+
+		assert(delay > 0);
+	}
+
+	return delay;
+}
+
+
+int get_age(struct ospf_lsa *lsa)
+{
+	struct timeval rel;
+
+	/* As per rfc4136, the self-originated LSAs in their
+	 * own database keep aging, however rfc doesn't tell
+	 * till how long the LSA should be aged, as of now
+	 * we are capping it for OSPF_LSA_MAXAGE.
+	 */
+
+	/* If LSA is marked as donotage */
+	if (CHECK_FLAG(lsa->data->ls_age, DO_NOT_AGE) && !IS_LSA_SELF(lsa))
+		return ntohs(lsa->data->ls_age);
+
+	monotime_since(&lsa->tv_recv, &rel);
+	return ntohs(lsa->data->ls_age) + rel.tv_sec;
+}
+
+
+/* Fletcher Checksum -- Refer to RFC1008. */
+
+/* All the offsets are zero-based. The offsets in the RFC1008 are
+   one-based. */
+uint16_t ospf_lsa_checksum(struct lsa_header *lsa)
+{
+	uint8_t *buffer = &lsa->options;
+	int options_offset = buffer - (uint8_t *)&lsa->ls_age; /* should be 2 */
+
+	/* Skip the AGE field */
+	uint16_t len = ntohs(lsa->length) - options_offset;
+
+	/* Checksum offset starts from "options" field, not the beginning of the
+	   lsa_header struct. The offset is 14, rather than 16. */
+	int checksum_offset = (uint8_t *)&lsa->checksum - buffer;
+
+	return fletcher_checksum(buffer, len, checksum_offset);
+}
+
+int ospf_lsa_checksum_valid(struct lsa_header *lsa)
+{
+	uint8_t *buffer = &lsa->options;
+	int options_offset = buffer - (uint8_t *)&lsa->ls_age; /* should be 2 */
+
+	/* Skip the AGE field */
+	uint16_t len = ntohs(lsa->length) - options_offset;
+
+	return (fletcher_checksum(buffer, len, FLETCHER_CHECKSUM_VALIDATE)
+		== 0);
+}
+
+
+/* Create OSPF LSA. */
+struct ospf_lsa *ospf_lsa_new(void)
+{
+	struct ospf_lsa *new;
+
+	new = XCALLOC(MTYPE_OSPF_LSA, sizeof(struct ospf_lsa));
+
+	new->flags = 0;
+	new->lock = 1;
+	new->retransmit_counter = 0;
+	monotime(&new->tv_recv);
+	new->tv_orig = new->tv_recv;
+	new->refresh_list = -1;
+	new->vrf_id = VRF_DEFAULT;
+	new->to_be_acknowledged = 0;
+	new->opaque_zero_len_delete = 0;
+
+	return new;
+}
+
+struct ospf_lsa *ospf_lsa_new_and_data(size_t size)
+{
+	struct ospf_lsa *new;
+
+	new = ospf_lsa_new();
+	new->data = ospf_lsa_data_new(size);
+	new->size = size;
+
+	return new;
+}
+
+/* Duplicate OSPF LSA. */
+struct ospf_lsa *ospf_lsa_dup(struct ospf_lsa *lsa)
+{
+	struct ospf_lsa *new;
+
+	if (lsa == NULL)
+		return NULL;
+
+	new = XCALLOC(MTYPE_OSPF_LSA, sizeof(struct ospf_lsa));
+
+	memcpy(new, lsa, sizeof(struct ospf_lsa));
+	UNSET_FLAG(new->flags, OSPF_LSA_DISCARD);
+	new->lock = 1;
+	new->retransmit_counter = 0;
+	new->data = ospf_lsa_data_dup(lsa->data);
+
+	/* kevinm: Clear the refresh_list, otherwise there are going
+	   to be problems when we try to remove the LSA from the
+	   queue (which it's not a member of.)
+	   XXX: Should we add the LSA to the refresh_list queue? */
+	new->refresh_list = -1;
+
+	if (IS_DEBUG_OSPF(lsa, LSA))
+		zlog_debug("LSA: duplicated %p (new: %p)", (void *)lsa,
+			   (void *)new);
+
+	return new;
+}
+
+/* Free OSPF LSA. */
+void ospf_lsa_free(struct ospf_lsa *lsa)
+{
+	assert(lsa->lock == 0);
+
+	if (IS_DEBUG_OSPF(lsa, LSA))
+		zlog_debug("LSA: freed %p", (void *)lsa);
+
+	/* Delete LSA data. */
+	if (lsa->data != NULL)
+		ospf_lsa_data_free(lsa->data);
+
+	assert(lsa->refresh_list < 0);
+
+	memset(lsa, 0, sizeof(struct ospf_lsa));
+	XFREE(MTYPE_OSPF_LSA, lsa);
+}
+
+/* Lock LSA. */
+struct ospf_lsa *ospf_lsa_lock(struct ospf_lsa *lsa)
+{
+	lsa->lock++;
+	return lsa;
+}
+
+/* Unlock LSA. */
+void ospf_lsa_unlock(struct ospf_lsa **lsa)
+{
+	/* This is sanity check. */
+	if (!lsa || !*lsa)
+		return;
+
+	(*lsa)->lock--;
+
+	assert((*lsa)->lock >= 0);
+
+	if ((*lsa)->lock == 0) {
+		assert(CHECK_FLAG((*lsa)->flags, OSPF_LSA_DISCARD));
+		ospf_lsa_free(*lsa);
+		*lsa = NULL;
+	}
+}
+
+/* Check discard flag. */
+void ospf_lsa_discard(struct ospf_lsa *lsa)
+{
+	if (!CHECK_FLAG(lsa->flags, OSPF_LSA_DISCARD)) {
+		SET_FLAG(lsa->flags, OSPF_LSA_DISCARD);
+		ospf_lsa_unlock(&lsa);
+	}
+}
+
+/* Create LSA data. */
+struct lsa_header *ospf_lsa_data_new(size_t size)
+{
+	return XCALLOC(MTYPE_OSPF_LSA_DATA, size);
+}
+
+/* Duplicate LSA data. */
+struct lsa_header *ospf_lsa_data_dup(struct lsa_header *lsah)
+{
+	struct lsa_header *new;
+
+	new = ospf_lsa_data_new(ntohs(lsah->length));
+	memcpy(new, lsah, ntohs(lsah->length));
+
+	return new;
+}
+
+/* Free LSA data. */
+void ospf_lsa_data_free(struct lsa_header *lsah)
+{
+	if (IS_DEBUG_OSPF(lsa, LSA))
+		zlog_debug("LSA[Type%d:%pI4]: data freed %p", lsah->type,
+			   &lsah->id, (void *)lsah);
+
+	XFREE(MTYPE_OSPF_LSA_DATA, lsah);
+}
+
+
+/* LSA general functions. */
+
+const char *dump_lsa_key(struct ospf_lsa *lsa)
+{
+	static char buf[sizeof("Type255,id(255.255.255.255),ar(255.255.255.255)")+1];
+	struct lsa_header *lsah;
+
+	if (lsa != NULL && (lsah = lsa->data) != NULL) {
+		char id[INET_ADDRSTRLEN], ar[INET_ADDRSTRLEN];
+		inet_ntop(AF_INET, &lsah->id, id, sizeof(id));
+		inet_ntop(AF_INET, &lsah->adv_router, ar, sizeof(ar));
+
+		snprintf(buf, sizeof(buf), "Type%d,id(%s),ar(%s)", lsah->type,
+			 id, ar);
+	} else
+		strlcpy(buf, "NULL", sizeof(buf));
+
+	return buf;
+}
+
+uint32_t lsa_seqnum_increment(struct ospf_lsa *lsa)
+{
+	uint32_t seqnum;
+
+	seqnum = ntohl(lsa->data->ls_seqnum) + 1;
+
+	return htonl(seqnum);
+}
+
+void lsa_header_set(struct stream *s, uint8_t options, uint8_t type,
+		    struct in_addr id, struct in_addr router_id)
+{
+	struct lsa_header *lsah;
+
+	lsah = (struct lsa_header *)STREAM_DATA(s);
+
+	lsah->ls_age = htons(OSPF_LSA_INITIAL_AGE);
+	lsah->options = options;
+	lsah->type = type;
+	lsah->id = id;
+	lsah->adv_router = router_id;
+	lsah->ls_seqnum = htonl(OSPF_INITIAL_SEQUENCE_NUMBER);
+
+	stream_forward_endp(s, OSPF_LSA_HEADER_SIZE);
+}
+
+
+/* router-LSA related functions. */
+/* Get router-LSA flags. */
+uint8_t router_lsa_flags(struct ospf_area *area)
+{
+	uint8_t flags;
+
+	flags = area->ospf->flags;
+
+	/* Set virtual link flag. */
+	if (ospf_full_virtual_nbrs(area))
+		SET_FLAG(flags, ROUTER_LSA_VIRTUAL);
+	else
+		/* Just sanity check */
+		UNSET_FLAG(flags, ROUTER_LSA_VIRTUAL);
+
+	/* Set Shortcut ABR behabiour flag. */
+	UNSET_FLAG(flags, ROUTER_LSA_SHORTCUT);
+	if (area->ospf->abr_type == OSPF_ABR_SHORTCUT)
+		if (!OSPF_IS_AREA_BACKBONE(area))
+			if ((area->shortcut_configured == OSPF_SHORTCUT_DEFAULT
+			     && area->ospf->backbone == NULL)
+			    || area->shortcut_configured
+				       == OSPF_SHORTCUT_ENABLE)
+				SET_FLAG(flags, ROUTER_LSA_SHORTCUT);
+
+	/* ASBR can't exit in stub area. */
+	if (area->external_routing == OSPF_AREA_STUB)
+		UNSET_FLAG(flags, ROUTER_LSA_EXTERNAL);
+	/* If ASBR set External flag */
+	else if (IS_OSPF_ASBR(area->ospf))
+		SET_FLAG(flags, ROUTER_LSA_EXTERNAL);
+
+	/* Set ABR dependent flags */
+	if (IS_OSPF_ABR(area->ospf)) {
+		SET_FLAG(flags, ROUTER_LSA_BORDER);
+		/* If Area is NSSA and we are both ABR and unconditional
+		 * translator,
+		 * set Nt bit to inform other routers.
+		 */
+		if ((area->external_routing == OSPF_AREA_NSSA)
+		    && (area->NSSATranslatorRole == OSPF_NSSA_ROLE_ALWAYS))
+			SET_FLAG(flags, ROUTER_LSA_NT);
+	}
+	return flags;
+}
+
+/* Lookup neighbor other than myself.
+   And check neighbor count,
+   Point-to-Point link must have only 1 neighbor. */
+struct ospf_neighbor *ospf_nbr_lookup_ptop(struct ospf_interface *oi)
+{
+	struct ospf_neighbor *nbr = NULL;
+	struct route_node *rn;
+
+	/* Search neighbor, there must be one of two nbrs. */
+	for (rn = route_top(oi->nbrs); rn; rn = route_next(rn))
+		if ((nbr = rn->info))
+			if (!IPV4_ADDR_SAME(&nbr->router_id,
+					    &oi->ospf->router_id))
+				if (nbr->state == NSM_Full) {
+					route_unlock_node(rn);
+					break;
+				}
+
+	/* PtoP link must have only 1 neighbor. */
+	if (ospf_nbr_count(oi, 0) > 1)
+		flog_warn(
+			EC_OSPF_PTP_NEIGHBOR,
+			"Point-to-Point link on interface %s has more than 1 neighbor.",
+			oi->ifp->name);
+
+	return nbr;
+}
+
+/* Determine cost of link, taking RFC3137 stub-router support into
+ * consideration
+ */
+static uint16_t ospf_link_cost(struct ospf_interface *oi)
+{
+	/* RFC3137 stub router support */
+	if (!CHECK_FLAG(oi->area->stub_router_state, OSPF_AREA_IS_STUB_ROUTED))
+		return oi->output_cost;
+	else
+		return OSPF_OUTPUT_COST_INFINITE;
+}
+
+/* Set a link information. */
+char link_info_set(struct stream **s, struct in_addr id, struct in_addr data,
+		   uint8_t type, uint8_t tos, uint16_t cost)
+{
+	/* LSA stream is initially allocated to OSPF_MAX_LSA_SIZE, suits
+	 * vast majority of cases. Some rare routers with lots of links need
+	 * more.
+	 * we try accommodate those here.
+	 */
+	if (STREAM_WRITEABLE(*s) < OSPF_ROUTER_LSA_LINK_SIZE) {
+		size_t ret = OSPF_MAX_LSA_SIZE;
+
+		/* Can we enlarge the stream still? */
+		if (STREAM_SIZE(*s) == OSPF_MAX_LSA_SIZE) {
+			/* we futz the size here for simplicity, really we need
+			 * to account
+			 * for just:
+			 * IP Header - (sizeof(struct ip))
+			 * OSPF Header - OSPF_HEADER_SIZE
+			 * LSA Header - OSPF_LSA_HEADER_SIZE
+			 * MD5 auth data, if MD5 is configured -
+			 * OSPF_AUTH_MD5_SIZE.
+			 *
+			 * Simpler just to subtract OSPF_MAX_LSA_SIZE though.
+			 */
+			ret = stream_resize_inplace(
+				s, OSPF_MAX_PACKET_SIZE - OSPF_MAX_LSA_SIZE);
+		}
+
+		if (ret == OSPF_MAX_LSA_SIZE) {
+			flog_warn(
+				EC_OSPF_LSA_SIZE,
+				"%s: Out of space in LSA stream, left %zd, size %zd",
+				__func__, STREAM_WRITEABLE(*s),
+				STREAM_SIZE(*s));
+			return 0;
+		}
+	}
+
+	/* TOS based routing is not supported. */
+	stream_put_ipv4(*s, id.s_addr);   /* Link ID. */
+	stream_put_ipv4(*s, data.s_addr); /* Link Data. */
+	stream_putc(*s, type);		  /* Link Type. */
+	stream_putc(*s, tos);		  /* TOS = 0. */
+	stream_putw(*s, cost);		  /* Link Cost. */
+
+	return 1;
+}
+
+/* Describe Point-to-Point link (Section 12.4.1.1). */
+
+/* Note: If the interface is configured as point-to-point dmvpn then the other
+ * end of link is dmvpn hub with point-to-multipoint ospf network type. The
+ * hub then expects this router to populate the stub network and also Link Data
+ * Field set to IP Address and not MIB-II ifIndex
+ */
+static int lsa_link_ptop_set(struct stream **s, struct ospf_interface *oi)
+{
+	int links = 0;
+	struct ospf_neighbor *nbr;
+	struct in_addr id, mask, data;
+	uint16_t cost = ospf_link_cost(oi);
+
+	if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+		zlog_debug("LSA[Type1]: Set link Point-to-Point");
+
+	if ((nbr = ospf_nbr_lookup_ptop(oi)))
+		if (nbr->state == NSM_Full) {
+			if (CHECK_FLAG(oi->connected->flags,
+				       ZEBRA_IFA_UNNUMBERED)
+			    && !oi->ptp_dmvpn) {
+				/* For unnumbered point-to-point networks, the
+				   Link Data field
+				   should specify the interface's MIB-II ifIndex
+				   value. */
+				data.s_addr = htonl(oi->ifp->ifindex);
+				links += link_info_set(
+					s, nbr->router_id, data,
+					LSA_LINK_TYPE_POINTOPOINT, 0, cost);
+			} else {
+				links += link_info_set(
+					s, nbr->router_id,
+					oi->address->u.prefix4,
+					LSA_LINK_TYPE_POINTOPOINT, 0, cost);
+			}
+		}
+
+	/* no need for a stub link for unnumbered interfaces */
+	if (OSPF_IF_PARAM(oi, prefix_suppression)) {
+		if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+			zlog_debug("LSA[Type1]: Interface %s stub link omitted due prefix-suppression",
+				   oi->ifp->name);
+	} else {
+		if (oi->ptp_dmvpn ||
+		    !CHECK_FLAG(oi->connected->flags, ZEBRA_IFA_UNNUMBERED)) {
+			/* Regardless of the state of the neighboring router, we must
+			   add a Type 3 link (stub network).
+			   N.B. Options 1 & 2 share basically the same logic. */
+			masklen2ip(oi->address->prefixlen, &mask);
+			id.s_addr =
+				CONNECTED_PREFIX(oi->connected)->u.prefix4.s_addr &
+				mask.s_addr;
+			links += link_info_set(s, id, mask, LSA_LINK_TYPE_STUB,
+					       0, oi->output_cost);
+		}
+	}
+
+	return links;
+}
+
+/* Describe Broadcast Link. */
+static int lsa_link_broadcast_set(struct stream **s, struct ospf_interface *oi)
+{
+	struct ospf_neighbor *dr;
+	struct in_addr id, mask;
+	uint16_t cost = ospf_link_cost(oi);
+
+	/* Describe Type 3 Link. */
+	if (oi->state == ISM_Waiting) {
+		if (OSPF_IF_PARAM(oi, prefix_suppression)) {
+			if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+				zlog_debug("LSA[Type1]: Interface %s stub link omitted due prefix-suppression",
+					   oi->ifp->name);
+			return 0;
+		}
+		if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+			zlog_debug("LSA[Type1]: Interface %s is in state Waiting. Adding stub interface",
+				   oi->ifp->name);
+		masklen2ip(oi->address->prefixlen, &mask);
+		id.s_addr = oi->address->u.prefix4.s_addr & mask.s_addr;
+		return link_info_set(s, id, mask, LSA_LINK_TYPE_STUB, 0,
+				     oi->output_cost);
+	}
+
+	dr = ospf_nbr_lookup_by_addr(oi->nbrs, &DR(oi));
+	/* Describe Type 2 link. */
+	if (dr && (dr->state == NSM_Full
+		   || IPV4_ADDR_SAME(&oi->address->u.prefix4, &DR(oi)))
+	    && ospf_nbr_count(oi, NSM_Full) > 0) {
+		if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+			zlog_debug(
+				"LSA[Type1]: Interface %s has a DR. Adding transit interface",
+				oi->ifp->name);
+		return link_info_set(s, DR(oi), oi->address->u.prefix4,
+				     LSA_LINK_TYPE_TRANSIT, 0, cost);
+	}
+	/* Describe type 3 link. */
+	else {
+		if (OSPF_IF_PARAM(oi, prefix_suppression)) {
+			if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+				zlog_debug("LSA[Type1]: Interface %s stub link omitted due prefix-suppression",
+					   oi->ifp->name);
+			return 0;
+		}
+		if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+			zlog_debug("LSA[Type1]: Interface %s has no DR. Adding stub interface",
+				   oi->ifp->name);
+		masklen2ip(oi->address->prefixlen, &mask);
+		id.s_addr = oi->address->u.prefix4.s_addr & mask.s_addr;
+		return link_info_set(s, id, mask, LSA_LINK_TYPE_STUB, 0,
+				     oi->output_cost);
+	}
+}
+
+static int lsa_link_loopback_set(struct stream **s, struct ospf_interface *oi)
+{
+	struct in_addr id, mask;
+
+	/* Describe Type 3 Link. */
+	if ((oi->state != ISM_Loopback) || OSPF_IF_PARAM(oi, prefix_suppression))
+		return 0;
+
+	mask.s_addr = 0xffffffff;
+	id.s_addr = oi->address->u.prefix4.s_addr;
+	return link_info_set(s, id, mask, LSA_LINK_TYPE_STUB, 0,
+			     oi->output_cost);
+}
+
+/* Describe Virtual Link. */
+static int lsa_link_virtuallink_set(struct stream **s,
+				    struct ospf_interface *oi)
+{
+	struct ospf_neighbor *nbr;
+	uint16_t cost = ospf_link_cost(oi);
+
+	if (oi->state == ISM_PointToPoint)
+		if ((nbr = ospf_nbr_lookup_ptop(oi)))
+			if (nbr->state == NSM_Full) {
+				return link_info_set(s, nbr->router_id,
+						     oi->address->u.prefix4,
+						     LSA_LINK_TYPE_VIRTUALLINK,
+						     0, cost);
+			}
+
+	return 0;
+}
+
+#define lsa_link_nbma_set(S,O)  lsa_link_broadcast_set (S, O)
+
+/* this function add for support point-to-multipoint ,see rfc2328
+12.4.1.4.*/
+/* from "edward rrr" <edward_rrr@hotmail.com>
+   http://marc.theaimsgroup.com/?l=zebra&m=100739222210507&w=2 */
+static int lsa_link_ptomp_set(struct stream **s, struct ospf_interface *oi)
+{
+	int links = 0;
+	struct route_node *rn;
+	struct ospf_neighbor *nbr = NULL;
+	struct in_addr id, mask;
+	uint16_t cost = ospf_link_cost(oi);
+
+	if (OSPF_IF_PARAM(oi, prefix_suppression)) {
+		if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+			zlog_debug("LSA[Type1]: Interface %s stub link omitted due prefix-suppression",
+				   oi->ifp->name);
+	} else {
+		mask.s_addr = 0xffffffff;
+		id.s_addr = oi->address->u.prefix4.s_addr;
+		links += link_info_set(s, id, mask, LSA_LINK_TYPE_STUB, 0, 0);
+	}
+
+	if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+		zlog_debug("PointToMultipoint: running ptomultip_set");
+
+	/* Search neighbor, */
+	for (rn = route_top(oi->nbrs); rn; rn = route_next(rn))
+		if ((nbr = rn->info) != NULL)
+			/* Ignore myself. */
+			if (!IPV4_ADDR_SAME(&nbr->router_id,
+					    &oi->ospf->router_id))
+				if (nbr->state == NSM_Full)
+
+				{
+					links += link_info_set(
+						s, nbr->router_id,
+						oi->address->u.prefix4,
+						LSA_LINK_TYPE_POINTOPOINT, 0,
+						cost);
+					if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+						zlog_debug(
+							"PointToMultipoint: set link to %pI4",
+							&oi->address->u.prefix4);
+				}
+
+	return links;
+}
+
+/* Set router-LSA link information. */
+static int router_lsa_link_set(struct stream **s, struct ospf_area *area)
+{
+	struct listnode *node;
+	struct ospf_interface *oi;
+	int links = 0;
+
+	for (ALL_LIST_ELEMENTS_RO(area->oiflist, node, oi)) {
+		struct interface *ifp = oi->ifp;
+
+		/* Check interface is up, OSPF is enable. */
+		if (if_is_operative(ifp)) {
+			if (oi->state != ISM_Down) {
+				oi->lsa_pos_beg = links;
+				/* Describe each link. */
+				switch (oi->type) {
+				case OSPF_IFTYPE_POINTOPOINT:
+					links += lsa_link_ptop_set(s, oi);
+					break;
+				case OSPF_IFTYPE_BROADCAST:
+					links += lsa_link_broadcast_set(s, oi);
+					break;
+				case OSPF_IFTYPE_NBMA:
+					links += lsa_link_nbma_set(s, oi);
+					break;
+				case OSPF_IFTYPE_POINTOMULTIPOINT:
+					links += lsa_link_ptomp_set(s, oi);
+					break;
+				case OSPF_IFTYPE_VIRTUALLINK:
+					links +=
+						lsa_link_virtuallink_set(s, oi);
+					break;
+				case OSPF_IFTYPE_LOOPBACK:
+					links += lsa_link_loopback_set(s, oi);
+				}
+				oi->lsa_pos_end = links;
+			}
+		}
+	}
+
+	return links;
+}
+
+/* Set router-LSA body. */
+void ospf_router_lsa_body_set(struct stream **s, struct ospf_area *area)
+{
+	unsigned long putp;
+	uint16_t cnt;
+
+	/* Set flags. */
+	stream_putc(*s, router_lsa_flags(area));
+
+	/* Set Zero fields. */
+	stream_putc(*s, 0);
+
+	/* Keep pointer to # links. */
+	putp = stream_get_endp(*s);
+
+	/* Forward word */
+	stream_putw(*s, 0);
+
+	/* Set all link information. */
+	cnt = router_lsa_link_set(s, area);
+
+	/* Set # of links here. */
+	stream_putw_at(*s, putp, cnt);
+}
+
+static void ospf_stub_router_timer(struct event *t)
+{
+	struct ospf_area *area = EVENT_ARG(t);
+
+	area->t_stub_router = NULL;
+
+	SET_FLAG(area->stub_router_state, OSPF_AREA_WAS_START_STUB_ROUTED);
+
+	/* clear stub route state and generate router-lsa refresh, don't
+	 * clobber an administratively set stub-router state though.
+	 */
+	if (CHECK_FLAG(area->stub_router_state, OSPF_AREA_ADMIN_STUB_ROUTED))
+		return;
+
+	UNSET_FLAG(area->stub_router_state, OSPF_AREA_IS_STUB_ROUTED);
+
+	ospf_router_lsa_update_area(area);
+}
+
+static void ospf_stub_router_check(struct ospf_area *area)
+{
+	/* area must either be administratively configured to be stub
+	 * or startup-time stub-router must be configured and we must in a
+	 * pre-stub
+	 * state.
+	 */
+	if (CHECK_FLAG(area->stub_router_state, OSPF_AREA_ADMIN_STUB_ROUTED)) {
+		SET_FLAG(area->stub_router_state, OSPF_AREA_IS_STUB_ROUTED);
+		return;
+	}
+
+	/* not admin-stubbed, check whether startup stubbing is configured and
+	 * whether it's not been done yet
+	 */
+	if (CHECK_FLAG(area->stub_router_state,
+		       OSPF_AREA_WAS_START_STUB_ROUTED))
+		return;
+
+	if (area->ospf->stub_router_startup_time
+	    == OSPF_STUB_ROUTER_UNCONFIGURED) {
+		/* stub-router is hence done forever for this area, even if
+		 * someone
+		 * tries configure it (take effect next restart).
+		 */
+		SET_FLAG(area->stub_router_state,
+			 OSPF_AREA_WAS_START_STUB_ROUTED);
+		return;
+	}
+
+	/* startup stub-router configured and not yet done */
+	SET_FLAG(area->stub_router_state, OSPF_AREA_IS_STUB_ROUTED);
+
+	OSPF_AREA_TIMER_ON(area->t_stub_router, ospf_stub_router_timer,
+			   area->ospf->stub_router_startup_time);
+}
+
+/* Create new router-LSA. */
+static struct ospf_lsa *ospf_router_lsa_new(struct ospf_area *area)
+{
+	struct ospf *ospf = area->ospf;
+	struct stream *s;
+	struct lsa_header *lsah;
+	struct ospf_lsa *new;
+	int length;
+
+	if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+		zlog_debug("LSA[Type1]: Create router-LSA instance");
+
+	/* check whether stub-router is desired, and if this is the first
+	 * router LSA.
+	 */
+	ospf_stub_router_check(area);
+
+	/* Create a stream for LSA. */
+	s = stream_new(OSPF_MAX_LSA_SIZE);
+	/* Set LSA common header fields. */
+	lsa_header_set(s, LSA_OPTIONS_GET(area) | LSA_OPTIONS_NSSA_GET(area),
+		       OSPF_ROUTER_LSA, ospf->router_id, ospf->router_id);
+
+	/* Set router-LSA body fields. */
+	ospf_router_lsa_body_set(&s, area);
+
+	/* Set length. */
+	length = stream_get_endp(s);
+	lsah = (struct lsa_header *)STREAM_DATA(s);
+	lsah->length = htons(length);
+
+	/* Now, create OSPF LSA instance. */
+	new = ospf_lsa_new_and_data(length);
+
+	new->area = area;
+	SET_FLAG(new->flags, OSPF_LSA_SELF | OSPF_LSA_SELF_CHECKED);
+	new->vrf_id = area->ospf->vrf_id;
+
+	/* Copy LSA data to store, discard stream. */
+	memcpy(new->data, lsah, length);
+	stream_free(s);
+
+	return new;
+}
+
+/* Originate Router-LSA. */
+static struct ospf_lsa *ospf_router_lsa_originate(struct ospf_area *area)
+{
+	struct ospf_lsa *new;
+
+	if (area->ospf->gr_info.restart_in_progress) {
+		if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+			zlog_debug(
+				"LSA[Type%d]: Graceful Restart in progress, don't originate",
+				OSPF_ROUTER_LSA);
+		return NULL;
+	}
+
+	/* Create new router-LSA instance. */
+	if ((new = ospf_router_lsa_new(area)) == NULL) {
+		zlog_err("%s: ospf_router_lsa_new returned NULL", __func__);
+		return NULL;
+	}
+
+	/* Sanity check. */
+	if (new->data->adv_router.s_addr == INADDR_ANY) {
+		if (IS_DEBUG_OSPF_EVENT)
+			zlog_debug("LSA[Type1]: AdvRouter is 0, discard");
+		ospf_lsa_discard(new);
+		return NULL;
+	}
+
+	/* Install LSA to LSDB. */
+	new = ospf_lsa_install(area->ospf, NULL, new);
+
+	/* Update LSA origination count. */
+	area->ospf->lsa_originate_count++;
+
+	/* Flooding new LSA through area. */
+	ospf_flood_through_area(area, NULL, new);
+
+	if (IS_DEBUG_OSPF(lsa, LSA_GENERATE)) {
+		zlog_debug("LSA[Type%d:%pI4]: Originate router-LSA %p",
+			   new->data->type, &new->data->id,
+			   (void *)new);
+		ospf_lsa_header_dump(new->data);
+	}
+
+	return new;
+}
+
+/* Refresh router-LSA. */
+static struct ospf_lsa *ospf_router_lsa_refresh(struct ospf_lsa *lsa)
+{
+	struct ospf_area *area = lsa->area;
+	struct ospf_lsa *new;
+
+	/* Sanity check. */
+	assert(lsa->data);
+
+	/* Delete LSA from neighbor retransmit-list. */
+	ospf_ls_retransmit_delete_nbr_area(area, lsa);
+
+	/* Unregister LSA from refresh-list */
+	ospf_refresher_unregister_lsa(area->ospf, lsa);
+
+	/* Create new router-LSA instance. */
+	if ((new = ospf_router_lsa_new(area)) == NULL) {
+		zlog_err("%s: ospf_router_lsa_new returned NULL", __func__);
+		return NULL;
+	}
+
+	new->data->ls_seqnum = lsa_seqnum_increment(lsa);
+
+	ospf_lsa_install(area->ospf, NULL, new);
+
+	/* Flood LSA through area. */
+	ospf_flood_through_area(area, NULL, new);
+
+	/* Debug logging. */
+	if (IS_DEBUG_OSPF(lsa, LSA_GENERATE)) {
+		zlog_debug("LSA[Type%d:%pI4]: router-LSA refresh",
+			   new->data->type, &new->data->id);
+		ospf_lsa_header_dump(new->data);
+	}
+
+	return NULL;
+}
+
+int ospf_router_lsa_update_area(struct ospf_area *area)
+{
+	if (IS_DEBUG_OSPF_EVENT)
+		zlog_debug("[router-LSA]: (router-LSA area update)");
+
+	/* Now refresh router-LSA. */
+	if (area->router_lsa_self)
+		ospf_lsa_refresh(area->ospf, area->router_lsa_self);
+	/* Newly originate router-LSA. */
+	else
+		ospf_router_lsa_originate(area);
+
+	return 0;
+}
+
+int ospf_router_lsa_update(struct ospf *ospf)
+{
+	struct listnode *node, *nnode;
+	struct ospf_area *area;
+
+	if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+		zlog_debug("Timer[router-LSA Update]: (timer expire)");
+
+	for (ALL_LIST_ELEMENTS(ospf->areas, node, nnode, area)) {
+		struct ospf_lsa *lsa = area->router_lsa_self;
+		struct router_lsa *rl;
+		const char *area_str;
+
+		/* Keep Area ID string. */
+		area_str = AREA_NAME(area);
+
+		/* If LSA not exist in this Area, originate new. */
+		if (lsa == NULL) {
+			if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+				zlog_debug(
+					"LSA[Type1]: Create router-LSA for Area %s",
+					area_str);
+
+			ospf_router_lsa_originate(area);
+		}
+		/* If router-ID is changed, Link ID must change.
+		   First flush old LSA, then originate new. */
+		else if (!IPV4_ADDR_SAME(&lsa->data->id, &ospf->router_id)) {
+			if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+				zlog_debug(
+					"LSA[Type%d:%pI4]: Refresh router-LSA for Area %s",
+					lsa->data->type,
+					&lsa->data->id, area_str);
+			ospf_refresher_unregister_lsa(ospf, lsa);
+			ospf_lsa_flush_area(lsa, area);
+			ospf_lsa_unlock(&area->router_lsa_self);
+			area->router_lsa_self = NULL;
+
+			/* Refresh router-LSA, (not install) and flood through
+			 * area. */
+			ospf_router_lsa_update_area(area);
+		} else {
+			rl = (struct router_lsa *)lsa->data;
+			/* Refresh router-LSA, (not install) and flood through
+			 * area. */
+			if (rl->flags != ospf->flags)
+				ospf_router_lsa_update_area(area);
+		}
+	}
+
+	return 0;
+}
+
+
+/* network-LSA related functions. */
+/* Originate Network-LSA. */
+static void ospf_network_lsa_body_set(struct stream *s,
+				      struct ospf_interface *oi)
+{
+	struct in_addr mask;
+	struct route_node *rn;
+	struct ospf_neighbor *nbr;
+
+	if (OSPF_IF_PARAM(oi, prefix_suppression)) {
+		mask.s_addr = 0xffffffff;
+		if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+			zlog_debug("LSA[Type2]: Interface %s network mask set to host mask due prefix-suppression",
+				   oi->ifp->name);
+	} else {
+		masklen2ip(oi->address->prefixlen, &mask);
+	}
+	stream_put_ipv4(s, mask.s_addr);
+
+	/* The network-LSA lists those routers that are fully adjacent to
+	  the Designated Router; each fully adjacent router is identified by
+	  its OSPF Router ID.  The Designated Router includes itself in this
+	  list. RFC2328, Section 12.4.2 */
+
+	for (rn = route_top(oi->nbrs); rn; rn = route_next(rn))
+		if ((nbr = rn->info) != NULL)
+			if (nbr->state == NSM_Full || nbr == oi->nbr_self)
+				stream_put_ipv4(s, nbr->router_id.s_addr);
+}
+
+static struct ospf_lsa *ospf_network_lsa_new(struct ospf_interface *oi)
+{
+	struct stream *s;
+	struct ospf_lsa *new;
+	struct lsa_header *lsah;
+	struct ospf_if_params *oip;
+	int length;
+
+	/* If there are no neighbours on this network (the net is stub),
+	   the router does not originate network-LSA (see RFC 12.4.2) */
+	if (oi->full_nbrs == 0)
+		return NULL;
+
+	if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+		zlog_debug("LSA[Type2]: Create network-LSA instance");
+
+	/* Create new stream for LSA. */
+	s = stream_new(OSPF_MAX_LSA_SIZE);
+	lsah = (struct lsa_header *)STREAM_DATA(s);
+
+	lsa_header_set(s, (OPTIONS(oi) | LSA_OPTIONS_GET(oi->area)),
+		       OSPF_NETWORK_LSA, DR(oi), oi->ospf->router_id);
+
+	/* Set network-LSA body fields. */
+	ospf_network_lsa_body_set(s, oi);
+
+	/* Set length. */
+	length = stream_get_endp(s);
+	lsah->length = htons(length);
+
+	/* Create OSPF LSA instance. */
+	new = ospf_lsa_new_and_data(length);
+
+	new->area = oi->area;
+	SET_FLAG(new->flags, OSPF_LSA_SELF | OSPF_LSA_SELF_CHECKED);
+	new->vrf_id = oi->ospf->vrf_id;
+
+	/* Copy LSA to store. */
+	memcpy(new->data, lsah, length);
+	stream_free(s);
+
+	/* Remember prior network LSA sequence numbers, even if we stop
+	 * originating one for this oi, to try avoid re-originating LSAs with a
+	 * prior sequence number, and thus speed up adjency forming &
+	 * convergence.
+	 */
+	if ((oip = ospf_lookup_if_params(oi->ifp, oi->address->u.prefix4))) {
+		new->data->ls_seqnum = oip->network_lsa_seqnum;
+		new->data->ls_seqnum = lsa_seqnum_increment(new);
+	} else {
+		oip = ospf_get_if_params(oi->ifp, oi->address->u.prefix4);
+		ospf_if_update_params(oi->ifp, oi->address->u.prefix4);
+	}
+	oip->network_lsa_seqnum = new->data->ls_seqnum;
+
+	return new;
+}
+
+/* Originate network-LSA. */
+void ospf_network_lsa_update(struct ospf_interface *oi)
+{
+	struct ospf_lsa *new;
+
+	if (oi->area->ospf->gr_info.restart_in_progress) {
+		if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+			zlog_debug(
+				"LSA[Type%d]: Graceful Restart in progress, don't originate",
+				OSPF_NETWORK_LSA);
+		return;
+	}
+
+	if (oi->network_lsa_self != NULL) {
+		ospf_lsa_refresh(oi->ospf, oi->network_lsa_self);
+		return;
+	}
+
+	/* Create new network-LSA instance. */
+	new = ospf_network_lsa_new(oi);
+	if (new == NULL)
+		return;
+
+	/* Install LSA to LSDB. */
+	new = ospf_lsa_install(oi->ospf, oi, new);
+
+	/* Update LSA origination count. */
+	oi->ospf->lsa_originate_count++;
+
+	/* Flooding new LSA through area. */
+	ospf_flood_through_area(oi->area, NULL, new);
+
+	if (IS_DEBUG_OSPF(lsa, LSA_GENERATE)) {
+		zlog_debug("LSA[Type%d:%pI4]: Originate network-LSA %p",
+			   new->data->type, &new->data->id,
+			   (void *)new);
+		ospf_lsa_header_dump(new->data);
+	}
+
+	return;
+}
+
+static struct ospf_lsa *ospf_network_lsa_refresh(struct ospf_lsa *lsa)
+{
+	struct ospf_area *area = lsa->area;
+	struct ospf_lsa *new, *new2;
+	struct ospf_if_params *oip;
+	struct ospf_interface *oi;
+
+	assert(lsa->data);
+
+	/* Retrieve the oi for the network LSA */
+	oi = ospf_if_lookup_by_local_addr(area->ospf, NULL, lsa->data->id);
+	if (oi == NULL) {
+		if (IS_DEBUG_OSPF(lsa, LSA_GENERATE)) {
+			zlog_debug(
+				"LSA[Type%d:%pI4]: network-LSA refresh: no oi found, ick, ignoring.",
+				lsa->data->type, &lsa->data->id);
+			ospf_lsa_header_dump(lsa->data);
+		}
+		return NULL;
+	}
+
+	if (oi->state != ISM_DR)
+		return NULL;
+
+	/* Delete LSA from neighbor retransmit-list. */
+	ospf_ls_retransmit_delete_nbr_area(area, lsa);
+
+	/* Unregister LSA from refresh-list */
+	ospf_refresher_unregister_lsa(area->ospf, lsa);
+
+	/* Create new network-LSA instance. */
+	new = ospf_network_lsa_new(oi);
+	if (new == NULL)
+		return NULL;
+
+	oip = ospf_lookup_if_params(oi->ifp, oi->address->u.prefix4);
+	assert(oip != NULL);
+	oip->network_lsa_seqnum = new->data->ls_seqnum =
+		lsa_seqnum_increment(lsa);
+
+	new2 = ospf_lsa_install(area->ospf, oi, new);
+
+	assert(new2 == new);
+
+	/* Flood LSA through aera. */
+	ospf_flood_through_area(area, NULL, new);
+
+	if (IS_DEBUG_OSPF(lsa, LSA_GENERATE)) {
+		zlog_debug("LSA[Type%d:%pI4]: network-LSA refresh",
+			   new->data->type, &new->data->id);
+		ospf_lsa_header_dump(new->data);
+	}
+
+	return new;
+}
+
+static void stream_put_ospf_metric(struct stream *s, uint32_t metric_value)
+{
+	uint32_t metric;
+	char *mp;
+
+	/* Put 0 metric. TOS metric is not supported. */
+	metric = htonl(metric_value);
+	mp = (char *)&metric;
+	mp++;
+	stream_put(s, mp, 3);
+}
+
+/* summary-LSA related functions. */
+static void ospf_summary_lsa_body_set(struct stream *s, struct prefix *p,
+				      uint32_t metric)
+{
+	struct in_addr mask;
+
+	masklen2ip(p->prefixlen, &mask);
+
+	/* Put Network Mask. */
+	stream_put_ipv4(s, mask.s_addr);
+
+	/* Set # TOS. */
+	stream_putc(s, (uint8_t)0);
+
+	/* Set metric. */
+	stream_put_ospf_metric(s, metric);
+}
+
+static struct ospf_lsa *ospf_summary_lsa_new(struct ospf_area *area,
+					     struct prefix *p, uint32_t metric,
+					     struct in_addr id)
+{
+	struct stream *s;
+	struct ospf_lsa *new;
+	struct lsa_header *lsah;
+	int length;
+
+	if (id.s_addr == 0xffffffff) {
+		/* Maybe Link State ID not available. */
+		if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+			zlog_debug(
+				"LSA[Type%d]: Link ID not available, can't originate",
+				OSPF_SUMMARY_LSA);
+		return NULL;
+	}
+
+	if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+		zlog_debug("LSA[Type3]: Create summary-LSA instance");
+
+	/* Create new stream for LSA. */
+	s = stream_new(OSPF_MAX_LSA_SIZE);
+	lsah = (struct lsa_header *)STREAM_DATA(s);
+
+	lsa_header_set(s, LSA_OPTIONS_GET(area), OSPF_SUMMARY_LSA, id,
+		       area->ospf->router_id);
+
+	/* Set summary-LSA body fields. */
+	ospf_summary_lsa_body_set(s, p, metric);
+
+	/* Set length. */
+	length = stream_get_endp(s);
+	lsah->length = htons(length);
+
+	/* Create OSPF LSA instance. */
+	new = ospf_lsa_new_and_data(length);
+	new->area = area;
+	SET_FLAG(new->flags, OSPF_LSA_SELF | OSPF_LSA_SELF_CHECKED);
+	new->vrf_id = area->ospf->vrf_id;
+
+	/* Copy LSA to store. */
+	memcpy(new->data, lsah, length);
+	stream_free(s);
+
+	return new;
+}
+
+/* Originate Summary-LSA. */
+static struct ospf_lsa *
+ospf_summary_lsa_prepare_and_flood(struct prefix_ipv4 *p, uint32_t metric,
+				   struct ospf_area *area, struct in_addr id)
+{
+	struct ospf_lsa *new;
+
+	/* Create new summary-LSA instance. */
+	if (!(new = ospf_summary_lsa_new(area, (struct prefix *)p, metric, id)))
+		return NULL;
+
+	/* Instlal LSA to LSDB. */
+	new = ospf_lsa_install(area->ospf, NULL, new);
+
+	/* Update LSA origination count. */
+	area->ospf->lsa_originate_count++;
+
+	/* Flooding new LSA through area. */
+	ospf_flood_through_area(area, NULL, new);
+
+	if (IS_DEBUG_OSPF(lsa, LSA_GENERATE)) {
+		zlog_debug("LSA[Type%d:%pI4]: Originate summary-LSA %p",
+			   new->data->type, &new->data->id,
+			   (void *)new);
+		ospf_lsa_header_dump(new->data);
+	}
+
+	return new;
+}
+
+static struct ospf_lsa *ospf_handle_summarylsa_lsId_chg(struct ospf_area *area,
+							struct prefix_ipv4 *p,
+							uint8_t type,
+							uint32_t metric,
+							struct in_addr old_id)
+{
+	struct ospf_lsa *lsa = NULL;
+	struct ospf_lsa *summary_lsa = NULL;
+	struct summary_lsa *sl = NULL;
+	struct ospf_area *old_area = NULL;
+	struct ospf *ospf = area->ospf;
+	struct prefix_ipv4 old_prefix;
+	uint32_t old_metric;
+	struct in_addr mask;
+	uint32_t metric_val;
+	char *metric_buf;
+
+	lsa = ospf_lsdb_lookup_by_id(area->lsdb, type, p->prefix,
+				     ospf->router_id);
+
+	if (!lsa) {
+		flog_warn(EC_OSPF_LSA_NULL, "(%s): LSA not found", __func__);
+		return NULL;
+	}
+
+	sl = (struct summary_lsa *)lsa->data;
+
+	old_area = lsa->area;
+	old_metric = GET_METRIC(sl->metric);
+	old_prefix.prefix = sl->header.id;
+	old_prefix.prefixlen = ip_masklen(sl->mask);
+	old_prefix.family = AF_INET;
+
+
+	/* change the mask */
+	masklen2ip(p->prefixlen, &mask);
+	sl->mask.s_addr = mask.s_addr;
+
+	/* Copy the metric*/
+	metric_val = htonl(metric);
+	metric_buf = (char *)&metric_val;
+	memcpy(sl->metric, metric_buf, sizeof(metric_val));
+
+	if (type == OSPF_SUMMARY_LSA) {
+		/*Refresh the LSA with new LSA*/
+		summary_lsa = ospf_summary_lsa_refresh(ospf, lsa);
+
+		ospf_summary_lsa_prepare_and_flood(&old_prefix, old_metric,
+						   old_area, old_id);
+	} else {
+		/*Refresh the LSA with new LSA*/
+		summary_lsa = ospf_summary_asbr_lsa_refresh(ospf, lsa);
+
+		ospf_asbr_summary_lsa_prepare_and_flood(&old_prefix, old_metric,
+							old_area, old_id);
+	}
+
+	return summary_lsa;
+}
+
+/* Originate Summary-LSA. */
+struct ospf_lsa *ospf_summary_lsa_originate(struct prefix_ipv4 *p,
+					    uint32_t metric,
+					    struct ospf_area *area)
+{
+	struct in_addr id;
+	enum lsid_status status;
+	struct ospf_lsa *new = NULL;
+
+	status = ospf_lsa_unique_id(area->ospf, area->lsdb, OSPF_SUMMARY_LSA, p,
+				    &id);
+
+	if (status == LSID_CHANGE) {
+		if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+			zlog_debug("Link ID has to be changed.");
+
+		new = ospf_handle_summarylsa_lsId_chg(area, p, OSPF_SUMMARY_LSA,
+						      metric, id);
+		return new;
+	} else if (status == LSID_NOT_AVAILABLE) {
+		/* Link State ID not available. */
+		if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+			zlog_debug(
+				"LSA[Type5]: Link ID not available, can't originate");
+
+		return NULL;
+	}
+
+	new = ospf_summary_lsa_prepare_and_flood(p, metric, area, id);
+	return new;
+}
+
+static struct ospf_lsa *ospf_summary_lsa_refresh(struct ospf *ospf,
+						 struct ospf_lsa *lsa)
+{
+	struct ospf_lsa *new;
+	struct summary_lsa *sl;
+	struct prefix p;
+
+	/* Sanity check. */
+	assert(lsa->data);
+
+	sl = (struct summary_lsa *)lsa->data;
+	p.prefixlen = ip_masklen(sl->mask);
+	new = ospf_summary_lsa_new(lsa->area, &p, GET_METRIC(sl->metric),
+				   sl->header.id);
+
+	if (!new)
+		return NULL;
+
+	new->data->ls_seqnum = lsa_seqnum_increment(lsa);
+
+	ospf_lsa_install(ospf, NULL, new);
+
+	/* Flood LSA through AS. */
+	ospf_flood_through_area(new->area, NULL, new);
+
+	/* Debug logging. */
+	if (IS_DEBUG_OSPF(lsa, LSA_GENERATE)) {
+		zlog_debug("LSA[Type%d:%pI4]: summary-LSA refresh",
+			   new->data->type, &new->data->id);
+		ospf_lsa_header_dump(new->data);
+	}
+
+	return new;
+}
+
+
+/* summary-ASBR-LSA related functions. */
+static void ospf_summary_asbr_lsa_body_set(struct stream *s, struct prefix *p,
+					   uint32_t metric)
+{
+	/* Put Network Mask. */
+	stream_put_ipv4(s, (uint32_t)0);
+
+	/* Set # TOS. */
+	stream_putc(s, (uint8_t)0);
+
+	/* Set metric. */
+	stream_put_ospf_metric(s, metric);
+}
+
+static struct ospf_lsa *ospf_summary_asbr_lsa_new(struct ospf_area *area,
+						  struct prefix *p,
+						  uint32_t metric,
+						  struct in_addr id)
+{
+	struct stream *s;
+	struct ospf_lsa *new;
+	struct lsa_header *lsah;
+	int length;
+
+	if (id.s_addr == 0xffffffff) {
+		/* Maybe Link State ID not available. */
+		if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+			zlog_debug(
+				"LSA[Type%d]: Link ID not available, can't originate",
+				OSPF_ASBR_SUMMARY_LSA);
+		return NULL;
+	}
+
+	if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+		zlog_debug("LSA[Type3]: Create summary-LSA instance");
+
+	/* Create new stream for LSA. */
+	s = stream_new(OSPF_MAX_LSA_SIZE);
+	lsah = (struct lsa_header *)STREAM_DATA(s);
+
+	lsa_header_set(s, LSA_OPTIONS_GET(area), OSPF_ASBR_SUMMARY_LSA, id,
+		       area->ospf->router_id);
+
+	/* Set summary-LSA body fields. */
+	ospf_summary_asbr_lsa_body_set(s, p, metric);
+
+	/* Set length. */
+	length = stream_get_endp(s);
+	lsah->length = htons(length);
+
+	/* Create OSPF LSA instance. */
+	new = ospf_lsa_new_and_data(length);
+	new->area = area;
+	SET_FLAG(new->flags, OSPF_LSA_SELF | OSPF_LSA_SELF_CHECKED);
+	new->vrf_id = area->ospf->vrf_id;
+
+	/* Copy LSA to store. */
+	memcpy(new->data, lsah, length);
+	stream_free(s);
+
+	return new;
+}
+
+/* Originate summary-ASBR-LSA. */
+static struct ospf_lsa *
+ospf_asbr_summary_lsa_prepare_and_flood(struct prefix_ipv4 *p, uint32_t metric,
+					struct ospf_area *area,
+					struct in_addr id)
+{
+	struct ospf_lsa *new;
+
+	/* Create new summary-LSA instance. */
+	new = ospf_summary_asbr_lsa_new(area, (struct prefix *)p, metric, id);
+	if (!new)
+		return NULL;
+
+	/* Install LSA to LSDB. */
+	new = ospf_lsa_install(area->ospf, NULL, new);
+
+	/* Update LSA origination count. */
+	area->ospf->lsa_originate_count++;
+
+	/* Flooding new LSA through area. */
+	ospf_flood_through_area(area, NULL, new);
+
+	if (IS_DEBUG_OSPF(lsa, LSA_GENERATE)) {
+		zlog_debug("LSA[Type%d:%pI4]: Originate summary-ASBR-LSA %p",
+			   new->data->type, &new->data->id,
+			   (void *)new);
+		ospf_lsa_header_dump(new->data);
+	}
+
+	return new;
+}
+
+struct ospf_lsa *ospf_summary_asbr_lsa_originate(struct prefix_ipv4 *p,
+						 uint32_t metric,
+						 struct ospf_area *area)
+{
+	struct ospf_lsa *new;
+	struct in_addr id;
+	enum lsid_status status;
+
+	status = ospf_lsa_unique_id(area->ospf, area->lsdb,
+				    OSPF_ASBR_SUMMARY_LSA, p, &id);
+
+	if (status == LSID_CHANGE) {
+		if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+			zlog_debug("Link ID has to be changed.");
+
+		new = ospf_handle_summarylsa_lsId_chg(
+			area, p, OSPF_ASBR_SUMMARY_LSA, metric, id);
+		return new;
+	} else if (status == LSID_NOT_AVAILABLE) {
+		/* Link State ID not available. */
+		if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+			zlog_debug(
+				"LSA[Type5]: Link ID not available, can't originate");
+
+		return NULL;
+	}
+
+	new = ospf_asbr_summary_lsa_prepare_and_flood(p, metric, area, id);
+	return new;
+}
+
+static struct ospf_lsa *ospf_summary_asbr_lsa_refresh(struct ospf *ospf,
+						      struct ospf_lsa *lsa)
+{
+	struct ospf_lsa *new;
+	struct summary_lsa *sl;
+	struct prefix p;
+	bool ind_lsa = false;
+
+	/* Sanity check. */
+	assert(lsa->data);
+
+	if (lsa->area->fr_info.indication_lsa_self &&
+	    (lsa->area->fr_info.indication_lsa_self == lsa))
+		ind_lsa = true;
+
+	sl = (struct summary_lsa *)lsa->data;
+	p.prefixlen = ip_masklen(sl->mask);
+	new = ospf_summary_asbr_lsa_new(lsa->area, &p, GET_METRIC(sl->metric),
+					sl->header.id);
+	if (!new)
+		return NULL;
+
+	new->data->ls_seqnum = lsa_seqnum_increment(lsa);
+
+	ospf_lsa_install(ospf, NULL, new);
+
+	/* Flood LSA through area. */
+	ospf_flood_through_area(new->area, NULL, new);
+
+	if (ind_lsa)
+		new->area->fr_info.indication_lsa_self = new;
+
+	if (IS_DEBUG_OSPF(lsa, LSA_GENERATE)) {
+		zlog_debug("LSA[Type%d:%pI4]: summary-ASBR-LSA refresh",
+			   new->data->type, &new->data->id);
+		ospf_lsa_header_dump(new->data);
+	}
+
+	return new;
+}
+
+/* AS-external-LSA related functions. */
+
+/* Get nexthop for AS-external-LSAs.  Return nexthop if its interface
+   is connected, else 0*/
+static struct in_addr ospf_external_lsa_nexthop_get(struct ospf *ospf,
+						    struct in_addr nexthop)
+{
+	struct in_addr fwd;
+	struct prefix nh;
+	struct listnode *node;
+	struct ospf_interface *oi;
+
+	fwd.s_addr = 0;
+
+	if (!nexthop.s_addr)
+		return fwd;
+
+	/* Check whether nexthop is covered by OSPF network. */
+	nh.family = AF_INET;
+	nh.u.prefix4 = nexthop;
+	nh.prefixlen = IPV4_MAX_BITLEN;
+
+	/* XXX/SCALE: If there were a lot of oi's on an ifp, then it'd be
+	 * better to make use of the per-ifp table of ois.
+	 */
+	for (ALL_LIST_ELEMENTS_RO(ospf->oiflist, node, oi))
+		if (if_is_operative(oi->ifp))
+			if (oi->address->family == AF_INET)
+				if (prefix_match(oi->address, &nh))
+					return nexthop;
+
+	return fwd;
+}
+
+/* NSSA-external-LSA related functions. */
+
+/* Get 1st IP connection for Forward Addr */
+
+struct in_addr ospf_get_ip_from_ifp(struct ospf_interface *oi)
+{
+	struct in_addr fwd;
+
+	fwd.s_addr = INADDR_ANY;
+
+	if (if_is_operative(oi->ifp))
+		return oi->address->u.prefix4;
+
+	return fwd;
+}
+
+/* Get 1st IP connection for Forward Addr */
+struct in_addr ospf_get_nssa_ip(struct ospf_area *area)
+{
+	struct in_addr fwd;
+	struct in_addr best_default;
+	struct listnode *node;
+	struct ospf_interface *oi;
+
+	fwd.s_addr = 0;
+	best_default.s_addr = 0;
+
+	for (ALL_LIST_ELEMENTS_RO(area->ospf->oiflist, node, oi)) {
+		if (if_is_operative(oi->ifp))
+			if (oi->area->external_routing == OSPF_AREA_NSSA)
+				if (oi->address
+				    && oi->address->family == AF_INET) {
+					if (best_default.s_addr == INADDR_ANY)
+						best_default =
+							oi->address->u.prefix4;
+					if (oi->area == area)
+						return oi->address->u.prefix4;
+				}
+	}
+	if (best_default.s_addr != INADDR_ANY)
+		return best_default;
+
+	return fwd;
+}
+
+int metric_type(struct ospf *ospf, uint8_t src, unsigned short instance)
+{
+	struct ospf_redist *red;
+
+	red = ospf_redist_lookup(ospf, src, instance);
+
+	return ((!red || red->dmetric.type < 0) ? DEFAULT_METRIC_TYPE
+						: red->dmetric.type);
+}
+
+int metric_value(struct ospf *ospf, uint8_t src, unsigned short instance)
+{
+	struct ospf_redist *red;
+
+	red = ospf_redist_lookup(ospf, src, instance);
+	if (!red || red->dmetric.value < 0) {
+		if (src == DEFAULT_ROUTE) {
+			if (ospf->default_originate == DEFAULT_ORIGINATE_ZEBRA)
+				return DEFAULT_DEFAULT_ORIGINATE_METRIC;
+			else
+				return DEFAULT_DEFAULT_ALWAYS_METRIC;
+		} else if (ospf->default_metric < 0)
+			return DEFAULT_DEFAULT_METRIC;
+		else
+			return ospf->default_metric;
+	}
+
+	return red->dmetric.value;
+}
+
+/* Set AS-external-LSA body. */
+static void ospf_external_lsa_body_set(struct stream *s,
+				       struct external_info *ei,
+				       struct ospf *ospf)
+{
+	struct prefix_ipv4 *p = &ei->p;
+	struct in_addr mask, fwd_addr;
+	uint32_t mvalue;
+	int mtype;
+	int type;
+	unsigned short instance;
+
+	/* Put Network Mask. */
+	masklen2ip(p->prefixlen, &mask);
+	stream_put_ipv4(s, mask.s_addr);
+
+	/* If prefix is default, specify DEFAULT_ROUTE. */
+	type = is_default_prefix4(&ei->p) ? DEFAULT_ROUTE : ei->type;
+	instance = is_default_prefix4(&ei->p) ? 0 : ei->instance;
+
+	mtype = (ROUTEMAP_METRIC_TYPE(ei) != -1)
+			? ROUTEMAP_METRIC_TYPE(ei)
+			: metric_type(ospf, type, instance);
+
+	mvalue = (ROUTEMAP_METRIC(ei) != -1)
+			 ? ROUTEMAP_METRIC(ei)
+			 : metric_value(ospf, type, instance);
+
+	/* Put type of external metric. */
+	stream_putc(s, (mtype == EXTERNAL_METRIC_TYPE_2 ? 0x80 : 0));
+
+	/* Put 0 metric. TOS metric is not supported. */
+	stream_put_ospf_metric(s, mvalue);
+
+	/* Get forwarding address to nexthop if on the Connection List, else 0.
+	 */
+	fwd_addr = ospf_external_lsa_nexthop_get(ospf, ei->nexthop);
+
+	/* Put forwarding address. */
+	stream_put_ipv4(s, fwd_addr.s_addr);
+
+	/* Put route tag */
+	stream_putl(s, ei->tag);
+}
+
+/* Create new external-LSA. */
+static struct ospf_lsa *
+ospf_exnl_lsa_prepare_and_flood(struct ospf *ospf, struct external_info *ei,
+				struct in_addr id)
+{
+	struct stream *s;
+	struct lsa_header *lsah;
+	struct ospf_lsa *new;
+	int length;
+
+	/* Create new stream for LSA. */
+	s = stream_new(OSPF_MAX_LSA_SIZE);
+	lsah = (struct lsa_header *)STREAM_DATA(s);
+
+	/* Set LSA common header fields. */
+	lsa_header_set(s, OSPF_OPTION_E, OSPF_AS_EXTERNAL_LSA, id,
+		       ospf->router_id);
+
+	/* Set AS-external-LSA body fields. */
+	ospf_external_lsa_body_set(s, ei, ospf);
+
+	/* Set length. */
+	length = stream_get_endp(s);
+	lsah->length = htons(length);
+
+	/* Now, create OSPF LSA instance. */
+	new = ospf_lsa_new_and_data(length);
+	new->area = NULL;
+	SET_FLAG(new->flags,
+		 OSPF_LSA_SELF | OSPF_LSA_APPROVED | OSPF_LSA_SELF_CHECKED);
+	new->vrf_id = ospf->vrf_id;
+
+	/* Copy LSA data to store, discard stream. */
+	memcpy(new->data, lsah, length);
+	stream_free(s);
+
+	return new;
+}
+
+static struct ospf_lsa *ospf_handle_exnl_lsa_lsId_chg(struct ospf *ospf,
+						      struct external_info *ei,
+						      struct in_addr id)
+{
+	struct ospf_lsa *lsa;
+	struct as_external_lsa *al;
+	struct in_addr mask;
+	struct ospf_lsa *new;
+	struct external_info ei_summary = {};
+	struct external_info *ei_old;
+
+	lsa = ospf_lsdb_lookup_by_id(ospf->lsdb, OSPF_AS_EXTERNAL_LSA,
+				     ei->p.prefix, ospf->router_id);
+
+	if (!lsa) {
+		flog_warn(EC_OSPF_LSA_NULL, "(%s): LSA not found", __func__);
+		return NULL;
+	}
+
+	ei_old = ospf_external_info_check(ospf, lsa);
+
+	al = (struct as_external_lsa *)lsa->data;
+
+	if (!ei_old) {
+		/* eii_old pointer of LSA is NULL, this
+		 * must be external aggregate route.
+		 */
+		ei_summary.p.family = AF_INET;
+		ei_summary.p.prefix = al->header.id;
+		ei_summary.p.prefixlen = ip_masklen(al->mask);
+		ei_summary.tag = (unsigned long)ntohl(al->e[0].route_tag);
+		ei_old = &ei_summary;
+	}
+
+	/* change the mask */
+	masklen2ip(ei->p.prefixlen, &mask);
+	al->mask.s_addr = mask.s_addr;
+
+	/*Refresh the LSA with new LSA*/
+	ospf_external_lsa_refresh(ospf, lsa, ei, LSA_REFRESH_FORCE, 0);
+
+	/*Originate the old LSA with changed LSID*/
+	new = ospf_exnl_lsa_prepare_and_flood(ospf, ei_old, id);
+
+	return new;
+}
+
+static struct ospf_lsa *ospf_external_lsa_new(struct ospf *ospf,
+					      struct external_info *ei,
+					      struct in_addr *old_id)
+{
+	struct ospf_lsa *new;
+	struct in_addr id;
+	enum lsid_status status;
+
+	if (ei == NULL) {
+		if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+			zlog_debug(
+				"LSA[Type5]: External info is NULL, can't originate");
+		return NULL;
+	}
+
+	if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+		zlog_debug("LSA[Type5]: Originate AS-external-LSA instance");
+
+	/* If old Link State ID is specified, refresh LSA with same ID. */
+	if (old_id)
+		id = *old_id;
+	/* Get Link State with unique ID. */
+	else {
+		status = ospf_lsa_unique_id(ospf, ospf->lsdb,
+					    OSPF_AS_EXTERNAL_LSA, &ei->p, &id);
+
+		if (status == LSID_CHANGE) {
+			if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+				zlog_debug("Link ID has to be changed.");
+
+			new = ospf_handle_exnl_lsa_lsId_chg(ospf, ei, id);
+			return new;
+		} else if (status == LSID_NOT_AVAILABLE) {
+			/* Link State ID not available. */
+			if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+				zlog_debug(
+					"LSA[Type5]: Link ID not available, can't originate");
+			return NULL;
+		}
+	}
+
+	new = ospf_exnl_lsa_prepare_and_flood(ospf, ei, id);
+
+	return new;
+}
+
+/* As Type-7 */
+static void ospf_install_flood_nssa(struct ospf *ospf, struct ospf_lsa *lsa)
+{
+	struct ospf_lsa *new;
+	struct as_external_lsa *extlsa;
+	struct ospf_area *area;
+	struct listnode *node, *nnode;
+
+	/* LSA may be a Type-5 originated via translation of a Type-7 LSA
+	 * which originated from an NSSA area. In which case it should not be
+	 * flooded back to NSSA areas.
+	 */
+	if (CHECK_FLAG(lsa->flags, OSPF_LSA_LOCAL_XLT))
+		return;
+
+	/* NSSA Originate or Refresh (If anyNSSA)
+
+	LSA is self-originated. And just installed as Type-5.
+	Additionally, install as Type-7 LSDB for every attached NSSA.
+
+	P-Bit controls which ABR performs translation to outside world; If
+	we are an ABR....do not set the P-bit, because we send the Type-5,
+	not as the ABR Translator, but as the ASBR owner within the AS!
+
+	If we are NOT ABR, Flood through NSSA as Type-7 w/P-bit set.  The
+	elected ABR Translator will see the P-bit, Translate, and re-flood.
+
+	Later, ABR_TASK and P-bit will scan Type-7 LSDB and translate to
+	Type-5's to non-NSSA Areas.  (it will also attempt a re-install) */
+
+	for (ALL_LIST_ELEMENTS(ospf->areas, node, nnode, area)) {
+		/* Don't install Type-7 LSA's into nonNSSA area */
+		if (area->external_routing != OSPF_AREA_NSSA)
+			continue;
+
+		/* make lsa duplicate, lock=1 */
+		new = ospf_lsa_dup(lsa);
+		new->area = area;
+		new->data->type = OSPF_AS_NSSA_LSA;
+
+		/* set P-bit if not ABR */
+		if (!IS_OSPF_ABR(ospf)) {
+			SET_FLAG(new->data->options, OSPF_OPTION_NP);
+
+			/* set non-zero FWD ADDR
+
+			draft-ietf-ospf-nssa-update-09.txt
+
+			if the network between the NSSA AS boundary router and
+			the
+			adjacent AS is advertised into OSPF as an internal OSPF
+			route,
+			the forwarding address should be the next op address as
+			is cu
+			currently done with type-5 LSAs.  If the intervening
+			network is
+			not adversited into OSPF as an internal OSPF route and
+			the
+			type-7 LSA's P-bit is set a forwarding address should be
+			selected from one of the router's active OSPF interface
+			addresses
+			which belong to the NSSA.  If no such addresses exist,
+			then
+			no type-7 LSA's with the P-bit set should originate from
+			this
+			router.   */
+
+			/* kevinm: not updating lsa anymore, just new */
+			extlsa = (struct as_external_lsa *)(new->data);
+
+			if (extlsa->e[0].fwd_addr.s_addr == INADDR_ANY)
+				extlsa->e[0].fwd_addr = ospf_get_nssa_ip(
+					area); /* this NSSA area in ifp */
+
+			if (extlsa->e[0].fwd_addr.s_addr == INADDR_ANY) {
+				if (IS_DEBUG_OSPF_NSSA)
+					zlog_debug(
+						"LSA[Type-7]: Could not build FWD-ADDR");
+				ospf_lsa_discard(new);
+				return;
+			}
+		}
+
+		/* install also as Type-7 */
+		ospf_lsa_install(ospf, NULL,
+				 new); /* Remove Old, Lock New = 2 */
+
+		/* will send each copy, lock=2+n */
+		ospf_flood_through_as(
+			ospf, NULL, new); /* all attached NSSA's, no AS/STUBs */
+	}
+}
+
+static struct ospf_lsa *ospf_lsa_translated_nssa_new(struct ospf *ospf,
+						     struct ospf_lsa *type7)
+{
+
+	struct ospf_lsa *new;
+	struct as_external_lsa *ext, *extnew;
+	struct external_info ei;
+
+	ext = (struct as_external_lsa *)(type7->data);
+
+	/* need external_info struct, fill in bare minimum */
+	ei.p.family = AF_INET;
+	ei.p.prefix = type7->data->id;
+	ei.p.prefixlen = ip_masklen(ext->mask);
+	ei.type = ZEBRA_ROUTE_OSPF;
+	ei.nexthop = ext->header.adv_router;
+	ei.route_map_set.metric = -1;
+	ei.route_map_set.metric_type = -1;
+	ei.metric = DEFAULT_DEFAULT_METRIC;
+	ei.max_metric = OSPF_LS_INFINITY;
+	ei.min_metric = 0;
+	ei.tag = 0;
+	ei.instance = 0;
+
+	if ((new = ospf_external_lsa_new(ospf, &ei, &type7->data->id))
+	    == NULL) {
+		if (IS_DEBUG_OSPF_NSSA)
+			zlog_debug(
+				"%s: Could not originate Translated Type-5 for %pI4",
+				__func__, &ei.p.prefix);
+		return NULL;
+	}
+
+	extnew = (struct as_external_lsa *)(new->data);
+
+	/* copy over Type-7 data to new */
+	extnew->e[0].tos = ext->e[0].tos;
+	extnew->e[0].route_tag = ext->e[0].route_tag;
+	if (type7->area->suppress_fa) {
+		extnew->e[0].fwd_addr.s_addr = 0;
+		if (IS_DEBUG_OSPF_NSSA)
+			zlog_debug("%s: Suppress forwarding address for %pI4",
+				   __func__, &ei.p.prefix);
+	} else
+		extnew->e[0].fwd_addr.s_addr = ext->e[0].fwd_addr.s_addr;
+	new->data->ls_seqnum = type7->data->ls_seqnum;
+
+	/* add translated flag, checksum and lock new lsa */
+	SET_FLAG(new->flags, OSPF_LSA_LOCAL_XLT); /* Translated from 7  */
+
+	return new;
+}
+
+/* Originate Translated Type-5 for supplied Type-7 NSSA LSA */
+struct ospf_lsa *ospf_translated_nssa_originate(struct ospf *ospf,
+						struct ospf_lsa *type7,
+						struct ospf_lsa *type5)
+{
+	struct ospf_lsa *new, *translated_lsa;
+	struct as_external_lsa *extnew;
+
+	if (ospf->gr_info.restart_in_progress) {
+		if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+			zlog_debug(
+				"LSA[Translated Type5]: Graceful Restart in progress, don't originate");
+		return NULL;
+	}
+
+	/* we cant use ospf_external_lsa_originate() as we need to set
+	 * the OSPF_LSA_LOCAL_XLT flag, must originate by hand
+	 */
+
+	if ((translated_lsa = ospf_lsa_translated_nssa_new(ospf, type7)) ==
+	    NULL) {
+		if (IS_DEBUG_OSPF_NSSA)
+			zlog_debug(
+				"%s: Could not translate Type-7, Id %pI4, to Type-5",
+				__func__, &type7->data->id);
+		return NULL;
+	}
+
+	extnew = (struct as_external_lsa *)translated_lsa->data;
+
+	/* Update LSA sequence number from translated Type-5 LSA */
+	if (type5)
+		translated_lsa->data->ls_seqnum = lsa_seqnum_increment(type5);
+
+	if ((new = ospf_lsa_install(ospf, NULL, translated_lsa)) == NULL) {
+		flog_warn(EC_OSPF_LSA_INSTALL_FAILURE,
+			  "%s: Could not install LSA id %pI4", __func__,
+			  &type7->data->id);
+		ospf_lsa_free(translated_lsa);
+		return NULL;
+	}
+
+	if (IS_DEBUG_OSPF_NSSA) {
+		zlog_debug("%s: translated Type 7, installed", __func__);
+		ospf_lsa_header_dump(new->data);
+		zlog_debug("   Network mask: %d", ip_masklen(extnew->mask));
+		zlog_debug("   Forward addr: %pI4",
+			   &extnew->e[0].fwd_addr);
+	}
+
+	ospf->lsa_originate_count++;
+	ospf_flood_through_as(ospf, NULL, new);
+
+	return new;
+}
+
+/* Refresh Translated from NSSA AS-external-LSA. */
+struct ospf_lsa *ospf_translated_nssa_refresh(struct ospf *ospf,
+					      struct ospf_lsa *type7,
+					      struct ospf_lsa *type5)
+{
+	struct ospf_lsa *new = NULL, *translated_lsa = NULL;
+	struct as_external_lsa *extold = NULL;
+	uint32_t ls_seqnum = 0;
+
+	/* Sanity checks. */
+	assert(type7 || type5);
+	if (!(type7 || type5))
+		return NULL;
+	if (type7)
+		assert(type7->data);
+	if (type5)
+		assert(type5->data);
+	assert(ospf->anyNSSA);
+
+	/* get required data according to what has been given */
+	if (type7 && type5 == NULL) {
+		/* find the translated Type-5 for this Type-7 */
+		struct as_external_lsa *ext =
+			(struct as_external_lsa *)(type7->data);
+		struct prefix_ipv4 p = {
+			.prefix = type7->data->id,
+			.prefixlen = ip_masklen(ext->mask),
+			.family = AF_INET,
+		};
+
+		type5 = ospf_external_info_find_lsa(ospf, &p);
+	} else if (type5 && type7 == NULL) {
+		/* find the type-7 from which supplied type-5 was translated,
+		 * ie find first type-7 with same LSA Id.
+		 */
+		struct listnode *ln, *lnn;
+		struct route_node *rn;
+		struct ospf_lsa *lsa;
+		struct ospf_area *area;
+
+		for (ALL_LIST_ELEMENTS(ospf->areas, ln, lnn, area)) {
+			if (area->external_routing != OSPF_AREA_NSSA && !type7)
+				continue;
+
+			LSDB_LOOP (NSSA_LSDB(area), rn, lsa) {
+				if (lsa->data->id.s_addr
+				    == type5->data->id.s_addr) {
+					type7 = lsa;
+					break;
+				}
+			}
+		}
+	}
+
+	/* do we have type7? */
+	if (!type7) {
+		if (IS_DEBUG_OSPF_NSSA)
+			zlog_debug("%s: no Type-7 found for Type-5 LSA Id %pI4",
+				   __func__, &type5->data->id);
+		return NULL;
+	}
+
+	/* do we have valid translated type5? */
+	if (type5 == NULL || !CHECK_FLAG(type5->flags, OSPF_LSA_LOCAL_XLT)) {
+		if (IS_DEBUG_OSPF_NSSA)
+			zlog_debug(
+				"%s: No translated Type-5 found for Type-7 with Id %pI4",
+				__func__, &type7->data->id);
+		return NULL;
+	}
+
+	extold = (struct as_external_lsa *)type5->data;
+	if (type7->area->suppress_fa == 1) {
+		if (extold->e[0].fwd_addr.s_addr == 0)
+			ls_seqnum = ntohl(type5->data->ls_seqnum);
+	}
+
+	/* Delete LSA from neighbor retransmit-list. */
+	ospf_ls_retransmit_delete_nbr_as(ospf, type5);
+
+	/* create new translated LSA */
+	if ((translated_lsa = ospf_lsa_translated_nssa_new(ospf, type7)) ==
+	    NULL) {
+		if (IS_DEBUG_OSPF_NSSA)
+			zlog_debug(
+				"%s: Could not translate Type-7 for %pI4 to Type-5",
+				__func__, &type7->data->id);
+		return NULL;
+	}
+
+	if (type7->area->suppress_fa == 1) {
+		if (extold->e[0].fwd_addr.s_addr == 0)
+			translated_lsa->data->ls_seqnum = htonl(ls_seqnum + 1);
+	}
+
+	if (!(new = ospf_lsa_install(ospf, NULL, translated_lsa))) {
+		flog_warn(EC_OSPF_LSA_INSTALL_FAILURE,
+			  "%s: Could not install translated LSA, Id %pI4",
+			  __func__, &type7->data->id);
+		ospf_lsa_free(translated_lsa);
+		return NULL;
+	}
+
+	/* Flood LSA through area. */
+	ospf_flood_through_as(ospf, NULL, new);
+
+	return new;
+}
+
+/* Originate an AS-external-LSA, install and flood. */
+struct ospf_lsa *ospf_external_lsa_originate(struct ospf *ospf,
+					     struct external_info *ei)
+{
+	struct ospf_lsa *new;
+
+	if (ospf->gr_info.restart_in_progress) {
+		if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+			zlog_debug(
+				"LSA[Type5]: Graceful Restart in progress, don't originate");
+		return NULL;
+	}
+
+	/* Added for NSSA project....
+
+	     External LSAs are originated in ASBRs as usual, but for NSSA
+	   systems.
+	   there is the global Type-5 LSDB and a Type-7 LSDB installed for
+	   every area.  The Type-7's are flooded to every IR and every ABR; We
+	   install the Type-5 LSDB so that the normal "refresh" code operates
+	   as usual, and flag them as not used during ASE calculations.  The
+	   Type-7 LSDB is used for calculations.  Each Type-7 has a Forwarding
+	   Address of non-zero.
+
+	   If an ABR is the elected NSSA translator, following SPF and during
+	   the ABR task it will translate all the scanned Type-7's, with P-bit
+	   ON and not-self generated, and translate to Type-5's throughout the
+	   non-NSSA/STUB AS.
+
+	   A difference in operation depends whether this ASBR is an ABR
+	   or not.  If not an ABR, the P-bit is ON, to indicate that any
+	   elected NSSA-ABR can perform its translation.
+
+	   If an ABR, the P-bit is OFF;  No ABR will perform translation and
+	   this ASBR will flood the Type-5 LSA as usual.
+
+	   For the case where this ASBR is not an ABR, the ASE calculations
+	   are based on the Type-5 LSDB;  The Type-7 LSDB exists just to
+	   demonstrate to the user that there are LSA's that belong to any
+	   attached NSSA.
+
+	   Finally, it just so happens that when the ABR is translating every
+	   Type-7 into Type-5, it installs it into the Type-5 LSDB as an
+	   approved Type-5 (translated from Type-7);  at the end of translation
+	   if any Translated Type-5's remain unapproved, then they must be
+	   flushed from the AS.
+
+	   */
+
+	if (ospf->router_id.s_addr == INADDR_ANY) {
+		if (ei && IS_DEBUG_OSPF_EVENT)
+			zlog_debug(
+				"LSA[Type5:%pI4]: deferring AS-external-LSA origination, router ID is zero",
+				&ei->p.prefix);
+		return NULL;
+	}
+
+	/* Create new AS-external-LSA instance. */
+	if ((new = ospf_external_lsa_new(ospf, ei, NULL)) == NULL) {
+		if (ei && IS_DEBUG_OSPF_EVENT)
+			zlog_debug(
+				"LSA[Type5:%pI4]: Could not originate AS-external-LSA",
+				&ei->p.prefix);
+		return NULL;
+	}
+
+	/* Install newly created LSA into Type-5 LSDB, lock = 1. */
+	ospf_lsa_install(ospf, NULL, new);
+
+	/* Update LSA origination count. */
+	ospf->lsa_originate_count++;
+
+	/* Flooding new LSA. only to AS (non-NSSA/STUB) */
+	ospf_flood_through_as(ospf, NULL, new);
+
+	/* If there is any attached NSSA, do special handling */
+	if (ospf->anyNSSA &&
+	    /* stay away from translated LSAs! */
+	    !(CHECK_FLAG(new->flags, OSPF_LSA_LOCAL_XLT)))
+		ospf_install_flood_nssa(
+			ospf, new); /* Install/Flood Type-7 to all NSSAs */
+
+	/* Debug logging. */
+	if (IS_DEBUG_OSPF(lsa, LSA_GENERATE)) {
+		zlog_debug("LSA[Type%d:%pI4]: Originate AS-external-LSA %p",
+			   new->data->type, &new->data->id,
+			   (void *)new);
+		ospf_lsa_header_dump(new->data);
+	}
+
+	return new;
+}
+
+/* Originate an NSSA-LSA, install and flood. */
+struct ospf_lsa *ospf_nssa_lsa_originate(struct ospf_area *area,
+					 struct external_info *ei)
+{
+	struct ospf *ospf = area->ospf;
+	struct ospf_lsa *new;
+
+	if (ospf->gr_info.restart_in_progress) {
+		if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+			zlog_debug(
+				"LSA[Type7]: Graceful Restart in progress, don't originate");
+		return NULL;
+	}
+
+	if (ospf->router_id.s_addr == INADDR_ANY) {
+		if (IS_DEBUG_OSPF_EVENT)
+			zlog_debug(
+				"LSA[Type7:%pI4]: deferring NSSA-LSA origination, router ID is zero",
+				&ei->p.prefix);
+		return NULL;
+	}
+
+	/* Create new NSSA-LSA instance. */
+	if ((new = ospf_external_lsa_new(ospf, ei, NULL)) == NULL) {
+		if (IS_DEBUG_OSPF_EVENT)
+			zlog_debug(
+				"LSA[Type7:%pI4]: Could not originate NSSA-LSA",
+				&ei->p.prefix);
+		return NULL;
+	}
+	new->data->type = OSPF_AS_NSSA_LSA;
+	new->area = area;
+
+	/* Install newly created LSA into Type-7 LSDB. */
+	ospf_lsa_install(ospf, NULL, new);
+
+	/* Update LSA origination count. */
+	ospf->lsa_originate_count++;
+
+	/* Flooding new LSA */
+	ospf_flood_through_area(area, NULL, new);
+
+	/* Debug logging. */
+	if (IS_DEBUG_OSPF(lsa, LSA_GENERATE)) {
+		zlog_debug("LSA[Type%d:%pI4]: Originate NSSA-LSA %p",
+			   new->data->type, &new->data->id, (void *)new);
+		ospf_lsa_header_dump(new->data);
+	}
+
+	return new;
+}
+
+/* Refresh NSSA-LSA. */
+struct ospf_lsa *ospf_nssa_lsa_refresh(struct ospf_area *area,
+				       struct ospf_lsa *lsa,
+				       struct external_info *ei)
+{
+	struct ospf *ospf = area->ospf;
+	struct ospf_lsa *new;
+
+	/* Delete LSA from neighbor retransmit-list. */
+	ospf_ls_retransmit_delete_nbr_as(ospf, lsa);
+
+	/* Unregister AS-external-LSA from refresh-list. */
+	ospf_refresher_unregister_lsa(ospf, lsa);
+
+	/* Create new NSSA-LSA instance. */
+	if ((new = ospf_external_lsa_new(ospf, ei, NULL)) == NULL) {
+		if (IS_DEBUG_OSPF_EVENT)
+			zlog_debug(
+				"LSA[Type7:%pI4]: Could not originate NSSA-LSA",
+				&ei->p.prefix);
+		return NULL;
+	}
+	new->data->type = OSPF_AS_NSSA_LSA;
+	new->data->ls_seqnum = lsa_seqnum_increment(lsa);
+	new->area = area;
+
+	/* Install newly created LSA into Type-7 LSDB. */
+	ospf_lsa_install(ospf, NULL, new);
+
+	/* Flooding new LSA */
+	ospf_flood_through_area(area, NULL, new);
+
+	/* Debug logging. */
+	if (IS_DEBUG_OSPF(lsa, LSA_GENERATE)) {
+		zlog_debug("LSA[Type%d:%pI4]: NSSA-LSA refresh",
+			   new->data->type, &new->data->id);
+		ospf_lsa_header_dump(new->data);
+	}
+
+	return new;
+}
+
+static struct external_info *ospf_default_external_info(struct ospf *ospf)
+{
+	int type;
+	struct prefix_ipv4 p;
+	struct external_info *default_ei;
+	int ret = 0;
+
+	p.family = AF_INET;
+	p.prefix.s_addr = 0;
+	p.prefixlen = 0;
+
+	default_ei = ospf_external_info_lookup(ospf, DEFAULT_ROUTE, 0, &p);
+	if (!default_ei)
+		return NULL;
+
+	/* First, lookup redistributed default route. */
+	for (type = 0; type <= ZEBRA_ROUTE_MAX; type++) {
+		struct list *ext_list;
+
+		if (type == ZEBRA_ROUTE_OSPF)
+			continue;
+
+		ext_list = ospf->external[type];
+		if (!ext_list)
+			continue;
+
+		ret = ospf_external_default_routemap_apply_walk(ospf, ext_list,
+								default_ei);
+		if (ret)
+			return default_ei;
+	}
+
+	return NULL;
+}
+
+void ospf_external_lsa_rid_change(struct ospf *ospf)
+{
+	struct external_info *ei;
+	struct ospf_external_aggr_rt *aggr;
+	struct ospf_lsa *lsa = NULL;
+	int force;
+	int type;
+
+	for (type = 0; type < ZEBRA_ROUTE_MAX; type++) {
+		struct route_node *rn;
+		struct route_table *rt;
+		struct list *ext_list;
+		struct listnode *node;
+		struct ospf_external *ext;
+
+		ext_list = ospf->external[type];
+		if (!ext_list)
+			continue;
+
+		for (ALL_LIST_ELEMENTS_RO(ext_list, node, ext)) {
+			/* Originate As-external-LSA from all type of
+			 * distribute source.
+			 */
+			rt = ext->external_info;
+			if (!rt)
+				continue;
+
+			for (rn = route_top(rt); rn; rn = route_next(rn)) {
+				ei = rn->info;
+
+				if (!ei)
+					continue;
+
+				if (is_default_prefix4(&ei->p))
+					continue;
+
+				lsa = ospf_external_info_find_lsa(ospf, &ei->p);
+
+				aggr = ospf_external_aggr_match(ospf, &ei->p);
+				if (aggr) {
+
+					if (!ospf_redistribute_check(ospf, ei,
+								     NULL))
+						continue;
+
+					if (IS_DEBUG_OSPF(lsa, EXTNL_LSA_AGGR))
+						zlog_debug(
+							"Originate Summary LSA after reset/router-ID change");
+
+					/* Here the LSA is originated as new */
+					ospf_originate_summary_lsa(ospf, aggr,
+								   ei);
+				} else if (lsa) {
+					/* LSA needs to be refreshed even if
+					 * there is no change in the route
+					 * params if the LSA is in maxage.
+					 */
+					if (IS_LSA_MAXAGE(lsa))
+						force = LSA_REFRESH_FORCE;
+					else
+						force = LSA_REFRESH_IF_CHANGED;
+
+					ospf_external_lsa_refresh(ospf, lsa,
+								ei, force, 0);
+				} else {
+					if (!ospf_redistribute_check(ospf, ei,
+								     NULL))
+						continue;
+
+					if (!ospf_external_lsa_originate(ospf,
+									 ei))
+						flog_warn(
+							EC_OSPF_LSA_INSTALL_FAILURE,
+							"LSA: AS-external-LSA was not originated.");
+				}
+			}
+		}
+	}
+
+	ei = ospf_default_external_info(ospf);
+	if (ei && !ospf_external_lsa_originate(ospf, ei)) {
+		flog_warn(EC_OSPF_LSA_INSTALL_FAILURE,
+			"LSA: AS-external-LSA for default route was not originated.");
+	}
+}
+
+/* Flush any NSSA LSAs for given prefix */
+void ospf_nssa_lsa_flush(struct ospf *ospf, struct prefix_ipv4 *p)
+{
+	struct listnode *node, *nnode;
+	struct ospf_lsa *lsa = NULL;
+	struct ospf_area *area;
+
+	for (ALL_LIST_ELEMENTS(ospf->areas, node, nnode, area)) {
+		if (area->external_routing == OSPF_AREA_NSSA) {
+			lsa = ospf_lsa_lookup(ospf, area, OSPF_AS_NSSA_LSA,
+					      p->prefix, ospf->router_id);
+			if (!lsa) {
+				if (IS_DEBUG_OSPF(lsa, LSA_FLOODING))
+					zlog_debug(
+						"LSA: There is no such AS-NSSA-LSA %pFX in LSDB",
+						p);
+				continue;
+			}
+			ospf_ls_retransmit_delete_nbr_area(area, lsa);
+			if (!IS_LSA_MAXAGE(lsa)) {
+				ospf_refresher_unregister_lsa(ospf, lsa);
+				ospf_lsa_flush_area(lsa, area);
+			}
+		}
+	}
+}
+
+/* Flush an AS-external-LSA from LSDB and routing domain. */
+void ospf_external_lsa_flush(struct ospf *ospf, uint8_t type,
+			     struct prefix_ipv4 *p,
+			     ifindex_t ifindex /*, struct in_addr nexthop */)
+{
+	struct ospf_lsa *lsa;
+
+	if (IS_DEBUG_OSPF(lsa, LSA_FLOODING))
+		zlog_debug("LSA: Flushing AS-external-LSA %pFX", p);
+
+	/* First lookup LSA from LSDB. */
+	if (!(lsa = ospf_external_info_find_lsa(ospf, p))) {
+		if (IS_DEBUG_OSPF(lsa, LSA_FLOODING))
+			zlog_debug(
+				"LSA: There is no such AS-external-LSA %pFX in LSDB",
+				p);
+		return;
+	}
+
+	/* If LSA is selforiginated, not a translated LSA, and there is
+	 * NSSA area, flush Type-7 LSA's at first.
+	 */
+	if (IS_LSA_SELF(lsa) && (ospf->anyNSSA)
+	    && !(CHECK_FLAG(lsa->flags, OSPF_LSA_LOCAL_XLT)))
+		ospf_nssa_lsa_flush(ospf, p);
+
+	if (!IS_LSA_MAXAGE(lsa)) {
+		/* Sweep LSA from Link State Retransmit List. */
+		ospf_ls_retransmit_delete_nbr_as(ospf, lsa);
+
+		/* Unregister LSA from Refresh queue. */
+		ospf_refresher_unregister_lsa(ospf, lsa);
+
+		/* Flush AS-external-LSA through AS. */
+		ospf_lsa_flush_as(ospf, lsa);
+	}
+
+	if (IS_DEBUG_OSPF(lsa, LSA_FLOODING))
+		zlog_debug("%s: stop", __func__);
+}
+
+void ospf_external_lsa_refresh_default(struct ospf *ospf)
+{
+	struct prefix_ipv4 p;
+	struct external_info *ei;
+	struct ospf_lsa *lsa;
+
+	p.family = AF_INET;
+	p.prefixlen = 0;
+	p.prefix.s_addr = INADDR_ANY;
+
+	ei = ospf_default_external_info(ospf);
+	lsa = ospf_external_info_find_lsa(ospf, &p);
+
+	if (ei && lsa) {
+		if (IS_DEBUG_OSPF_EVENT)
+			zlog_debug("LSA[Type5:0.0.0.0]: Refresh AS-external-LSA %p",
+				(void *)lsa);
+		ospf_external_lsa_refresh(ospf, lsa, ei, LSA_REFRESH_FORCE,
+					  false);
+	} else if (ei && !lsa) {
+		if (IS_DEBUG_OSPF_EVENT)
+			zlog_debug(
+				"LSA[Type5:0.0.0.0]: Originate AS-external-LSA");
+		ospf_external_lsa_originate(ospf, ei);
+	} else if (lsa) {
+		if (IS_DEBUG_OSPF_EVENT)
+			zlog_debug("LSA[Type5:0.0.0.0]: Flush AS-external-LSA");
+		ospf_external_lsa_flush(ospf, DEFAULT_ROUTE, &p, 0);
+	}
+}
+
+void ospf_external_lsa_refresh_type(struct ospf *ospf, uint8_t type,
+				    unsigned short instance, int force)
+{
+	struct route_node *rn;
+	struct external_info *ei;
+	struct ospf_external *ext;
+
+	if (type == DEFAULT_ROUTE)
+		return;
+
+	ext = ospf_external_lookup(ospf, type, instance);
+
+	if (ext && EXTERNAL_INFO(ext)) {
+		/* Refresh each redistributed AS-external-LSAs. */
+		for (rn = route_top(EXTERNAL_INFO(ext)); rn;
+		     rn = route_next(rn)) {
+			ei = rn->info;
+			if (ei) {
+				if (!is_default_prefix4(&ei->p)) {
+					struct ospf_lsa *lsa;
+					struct ospf_external_aggr_rt *aggr;
+
+					aggr = ospf_external_aggr_match(ospf,
+								&ei->p);
+					lsa = ospf_external_info_find_lsa(
+								ospf, &ei->p);
+					if (aggr) {
+						/* Check the AS-external-LSA
+						 * should be originated.
+						 */
+						if (!ospf_redistribute_check(
+							    ospf, ei, NULL)) {
+
+							ospf_unlink_ei_from_aggr(
+								ospf, aggr, ei);
+							continue;
+						}
+
+						if (IS_DEBUG_OSPF(
+							    lsa,
+							    EXTNL_LSA_AGGR))
+							zlog_debug(
+								"%s: Send Aggreate LSA (%pFX)",
+								__func__,
+								&aggr->p);
+
+						ospf_originate_summary_lsa(
+							ospf, aggr, ei);
+
+					} else if (lsa) {
+
+						if (IS_LSA_MAXAGE(lsa))
+							force = LSA_REFRESH_FORCE;
+
+						ospf_external_lsa_refresh(
+							ospf, lsa, ei, force,
+							false);
+					} else {
+						if (!ospf_redistribute_check(
+							    ospf, ei, NULL))
+							continue;
+						ospf_external_lsa_originate(
+							ospf, ei);
+					}
+				}
+			}
+		}
+	}
+}
+
+/* Refresh AS-external-LSA. */
+struct ospf_lsa *ospf_external_lsa_refresh(struct ospf *ospf,
+					   struct ospf_lsa *lsa,
+					   struct external_info *ei, int force,
+					   bool is_aggr)
+{
+	struct ospf_lsa *new;
+	int changed = 0;
+
+	/* Check the AS-external-LSA should be originated. */
+	if (!is_aggr)
+		if (!ospf_redistribute_check(ospf, ei, &changed)) {
+			if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+				zlog_debug(
+					"LSA[Type%d:%pI4] Could not be refreshed, redist check fail",
+					lsa->data->type,
+					&lsa->data->id);
+
+			ospf_external_lsa_flush(ospf, ei->type, &ei->p,
+						ei->ifindex /*, ei->nexthop */);
+			return NULL;
+		}
+
+	if (!changed && !force) {
+		if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+			zlog_debug(
+				"LSA[Type%d:%pI4]: Not refreshed, not changed/forced",
+				lsa->data->type, &lsa->data->id);
+		return NULL;
+	}
+
+	/* Delete LSA from neighbor retransmit-list. */
+	ospf_ls_retransmit_delete_nbr_as(ospf, lsa);
+
+	/* Unregister AS-external-LSA from refresh-list. */
+	ospf_refresher_unregister_lsa(ospf, lsa);
+
+	new = ospf_external_lsa_new(ospf, ei, &lsa->data->id);
+
+	if (new == NULL) {
+		if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+			zlog_debug("LSA[Type%d:%pI4]: Could not be refreshed",
+				   lsa->data->type, &lsa->data->id);
+		return NULL;
+	}
+
+	new->data->ls_seqnum = lsa_seqnum_increment(lsa);
+
+	ospf_lsa_install(ospf, NULL, new); /* As type-5. */
+
+	/* Flood LSA through AS. */
+	ospf_flood_through_as(ospf, NULL, new);
+
+	/* If any attached NSSA, install as Type-7, flood to all NSSA Areas */
+	if (ospf->anyNSSA && !(CHECK_FLAG(new->flags, OSPF_LSA_LOCAL_XLT)))
+		ospf_install_flood_nssa(ospf,
+					new); /* Install/Flood per new rules */
+
+	/* Register self-originated LSA to refresh queue.
+	 * Translated LSAs should not be registered, but refreshed upon
+	 * refresh of the Type-7
+	 */
+	if (!CHECK_FLAG(new->flags, OSPF_LSA_LOCAL_XLT))
+		ospf_refresher_register_lsa(ospf, new);
+
+	/* Debug logging. */
+	if (IS_DEBUG_OSPF(lsa, LSA_GENERATE)) {
+		zlog_debug("LSA[Type%d:%pI4]: AS-external-LSA refresh",
+			   new->data->type, &new->data->id);
+		ospf_lsa_header_dump(new->data);
+	}
+
+	return new;
+}
+
+
+/* LSA installation functions. */
+
+/* Install router-LSA to an area. */
+static struct ospf_lsa *
+ospf_router_lsa_install(struct ospf *ospf, struct ospf_lsa *new, int rt_recalc)
+{
+	struct ospf_area *area = new->area;
+
+	/* RFC 2328 Section 13.2 Router-LSAs and network-LSAs
+	   The entire routing table must be recalculated, starting with
+	   the shortest path calculations for each area (not just the
+	   area whose link-state database has changed).
+	*/
+
+	if (IS_LSA_SELF(new)) {
+
+		/* Only install LSA if it is originated/refreshed by us.
+		 * If LSA was received by flooding, the RECEIVED flag is set so
+		 * do
+		 * not link the LSA */
+		if (CHECK_FLAG(new->flags, OSPF_LSA_RECEIVED))
+			return new; /* ignore stale LSA */
+
+		/* Set self-originated router-LSA. */
+		ospf_lsa_unlock(&area->router_lsa_self);
+		area->router_lsa_self = ospf_lsa_lock(new);
+
+		ospf_refresher_register_lsa(ospf, new);
+	}
+	if (rt_recalc)
+		ospf_spf_calculate_schedule(ospf, SPF_FLAG_ROUTER_LSA_INSTALL);
+	return new;
+}
+
+/* Install network-LSA to an area. */
+static struct ospf_lsa *ospf_network_lsa_install(struct ospf *ospf,
+						 struct ospf_interface *oi,
+						 struct ospf_lsa *new,
+						 int rt_recalc)
+{
+
+	/* RFC 2328 Section 13.2 Router-LSAs and network-LSAs
+	   The entire routing table must be recalculated, starting with
+	   the shortest path calculations for each area (not just the
+	   area whose link-state database has changed).
+	*/
+	if (IS_LSA_SELF(new)) {
+		/* We supposed that when LSA is originated by us, we pass the
+		   int
+		   for which it was originated. If LSA was received by flooding,
+		   the RECEIVED flag is set, so we do not link the LSA to the
+		   int. */
+		if (CHECK_FLAG(new->flags, OSPF_LSA_RECEIVED))
+			return new; /* ignore stale LSA */
+
+		ospf_lsa_unlock(&oi->network_lsa_self);
+		oi->network_lsa_self = ospf_lsa_lock(new);
+		ospf_refresher_register_lsa(ospf, new);
+	}
+	if (rt_recalc)
+		ospf_spf_calculate_schedule(ospf, SPF_FLAG_NETWORK_LSA_INSTALL);
+
+	return new;
+}
+
+/* Install summary-LSA to an area. */
+static struct ospf_lsa *
+ospf_summary_lsa_install(struct ospf *ospf, struct ospf_lsa *new, int rt_recalc)
+{
+	if (rt_recalc && !IS_LSA_SELF(new)) {
+/* RFC 2328 Section 13.2 Summary-LSAs
+   The best route to the destination described by the summary-
+   LSA must be recalculated (see Section 16.5).  If this
+   destination is an AS boundary router, it may also be
+   necessary to re-examine all the AS-external-LSAs.
+*/
+
+		ospf_spf_calculate_schedule(ospf, SPF_FLAG_SUMMARY_LSA_INSTALL);
+	}
+
+	if (IS_LSA_SELF(new))
+		ospf_refresher_register_lsa(ospf, new);
+
+	return new;
+}
+
+/* Install ASBR-summary-LSA to an area. */
+static struct ospf_lsa *ospf_summary_asbr_lsa_install(struct ospf *ospf,
+						      struct ospf_lsa *new,
+						      int rt_recalc)
+{
+	if (rt_recalc && !IS_LSA_SELF(new)) {
+/* RFC 2328 Section 13.2 Summary-LSAs
+   The best route to the destination described by the summary-
+   LSA must be recalculated (see Section 16.5).  If this
+   destination is an AS boundary router, it may also be
+   necessary to re-examine all the AS-external-LSAs.
+*/
+		ospf_spf_calculate_schedule(ospf,
+					    SPF_FLAG_ASBR_SUMMARY_LSA_INSTALL);
+	}
+
+	/* register LSA to refresh-list. */
+	if (IS_LSA_SELF(new))
+		ospf_refresher_register_lsa(ospf, new);
+
+	return new;
+}
+
+/* Install AS-external-LSA. */
+static struct ospf_lsa *ospf_external_lsa_install(struct ospf *ospf,
+						  struct ospf_lsa *new,
+						  int rt_recalc)
+{
+	ospf_ase_register_external_lsa(new, ospf);
+	/* If LSA is not self-originated, calculate an external route. */
+	if (rt_recalc) {
+		/* RFC 2328 Section 13.2 AS-external-LSAs
+		      The best route to the destination described by the AS-
+		      external-LSA must be recalculated (see Section 16.6).
+		*/
+
+		if (!IS_LSA_SELF(new))
+			ospf_ase_incremental_update(ospf, new);
+	}
+
+	if (new->data->type == OSPF_AS_NSSA_LSA) {
+		/* There is no point to register selforiginate Type-7 LSA for
+		 * refreshing. We rely on refreshing Type-5 LSA's
+		 */
+		if (IS_LSA_SELF(new))
+			return new;
+		else {
+			/* Try refresh type-5 translated LSA for this LSA, if
+			 * one exists.
+			 * New translations will be taken care of by the
+			 * abr_task.
+			 */
+			ospf_translated_nssa_refresh(ospf, new, NULL);
+			ospf_schedule_abr_task(ospf);
+		}
+	}
+
+	/* Register self-originated LSA to refresh queue.
+	 * Leave Translated LSAs alone if NSSA is enabled
+	 */
+	if (IS_LSA_SELF(new) && !CHECK_FLAG(new->flags, OSPF_LSA_LOCAL_XLT))
+		ospf_refresher_register_lsa(ospf, new);
+
+	return new;
+}
+
+void ospf_discard_from_db(struct ospf *ospf, struct ospf_lsdb *lsdb,
+			  struct ospf_lsa *lsa)
+{
+	struct ospf_lsa *old;
+
+	if (!lsdb)
+		return;
+
+	old = ospf_lsdb_lookup(lsdb, lsa);
+
+	if (!old)
+		return;
+
+	if (old->refresh_list >= 0)
+		ospf_refresher_unregister_lsa(ospf, old);
+
+	switch (old->data->type) {
+	case OSPF_AS_EXTERNAL_LSA:
+		ospf_ase_unregister_external_lsa(old, ospf);
+		ospf_ls_retransmit_delete_nbr_as(ospf, old);
+		break;
+	case OSPF_OPAQUE_AS_LSA:
+		ospf_ls_retransmit_delete_nbr_as(ospf, old);
+		break;
+	case OSPF_AS_NSSA_LSA:
+		ospf_ls_retransmit_delete_nbr_area(old->area, old);
+		ospf_ase_unregister_external_lsa(old, ospf);
+		break;
+	default:
+		ospf_ls_retransmit_delete_nbr_area(old->area, old);
+		break;
+	}
+
+	ospf_lsa_maxage_delete(ospf, old);
+	ospf_lsa_discard(old);
+}
+
+struct ospf_lsa *ospf_lsa_install(struct ospf *ospf, struct ospf_interface *oi,
+				  struct ospf_lsa *lsa)
+{
+	struct ospf_lsa *new = NULL;
+	struct ospf_lsa *old = NULL;
+	struct ospf_lsdb *lsdb = NULL;
+	int rt_recalc;
+
+	/* Set LSDB. */
+	switch (lsa->data->type) {
+	/* kevinm */
+	case OSPF_AS_NSSA_LSA:
+		if (lsa->area)
+			lsdb = lsa->area->lsdb;
+		else
+			lsdb = ospf->lsdb;
+		break;
+	case OSPF_AS_EXTERNAL_LSA:
+	case OSPF_OPAQUE_AS_LSA:
+		lsdb = ospf->lsdb;
+		break;
+	default:
+		if (lsa->area)
+			lsdb = lsa->area->lsdb;
+		break;
+	}
+
+	assert(lsdb);
+
+	/*  RFC 2328 13.2.  Installing LSAs in the database
+
+	      Installing a new LSA in the database, either as the result of
+	      flooding or a newly self-originated LSA, may cause the OSPF
+	      routing table structure to be recalculated.  The contents of the
+	      new LSA should be compared to the old instance, if present.  If
+	      there is no difference, there is no need to recalculate the
+	      routing table. When comparing an LSA to its previous instance,
+	      the following are all considered to be differences in contents:
+
+		  o   The LSA's Options field has changed.
+
+		  o   One of the LSA instances has LS age set to MaxAge, and
+		      the other does not.
+
+		  o   The length field in the LSA header has changed.
+
+		  o   The body of the LSA (i.e., anything outside the 20-byte
+		      LSA header) has changed. Note that this excludes changes
+		      in LS Sequence Number and LS Checksum.
+
+	*/
+	/* Look up old LSA and determine if any SPF calculation or incremental
+	   update is needed */
+	old = ospf_lsdb_lookup(lsdb, lsa);
+
+	/* Do comparison and record if recalc needed. */
+	rt_recalc = 0;
+	if (old == NULL || ospf_lsa_different(old, lsa, false)) {
+		/* Ref rfc3623 section 3.2.3
+		 * Installing new lsa or change in the existing LSA
+		 * or flushing existing LSA leads to topo change
+		 * and trigger SPF caculation.
+		 * So, router should be aborted from HELPER role
+		 * if it is detected as TOPO  change.
+		 */
+		if (ospf->active_restarter_cnt &&
+		    CHECK_LSA_TYPE_1_TO_5_OR_7(lsa->data->type)) {
+			if (old == NULL || ospf_lsa_different(old, lsa, true))
+				ospf_helper_handle_topo_chg(ospf, lsa);
+		}
+
+		rt_recalc = 1;
+	}
+
+	/*
+	   Sequence number check (Section 14.1 of rfc 2328)
+	   "Premature aging is used when it is time for a self-originated
+	    LSA's sequence number field to wrap.  At this point, the current
+	    LSA instance (having LS sequence number MaxSequenceNumber) must
+	    be prematurely aged and flushed from the routing domain before a
+	    new instance with sequence number equal to InitialSequenceNumber
+	    can be originated. "
+	 */
+
+	if (ntohl(lsa->data->ls_seqnum) - 1 == OSPF_MAX_SEQUENCE_NUMBER) {
+		if (ospf_lsa_is_self_originated(ospf, lsa)) {
+			lsa->data->ls_seqnum = htonl(OSPF_MAX_SEQUENCE_NUMBER);
+
+			if (!IS_LSA_MAXAGE(lsa))
+				lsa->flags |= OSPF_LSA_PREMATURE_AGE;
+			lsa->data->ls_age = htons(OSPF_LSA_MAXAGE);
+
+			if (IS_DEBUG_OSPF(lsa, LSA_REFRESH)) {
+				zlog_debug(
+					"%s() Premature Aging lsa %p, seqnum 0x%x",
+					__func__, lsa,
+					ntohl(lsa->data->ls_seqnum));
+				ospf_lsa_header_dump(lsa->data);
+			}
+		} else {
+			if (IS_DEBUG_OSPF(lsa, LSA_GENERATE)) {
+				zlog_debug(
+					"%s() got an lsa with seq 0x80000000 that was not self originated. Ignoring",
+					__func__);
+				ospf_lsa_header_dump(lsa->data);
+			}
+			return old;
+		}
+	}
+
+	/* discard old LSA from LSDB */
+	if (old != NULL)
+		ospf_discard_from_db(ospf, lsdb, lsa);
+
+	/* Calculate Checksum if self-originated?. */
+	if (IS_LSA_SELF(lsa))
+		ospf_lsa_checksum(lsa->data);
+
+	/* Insert LSA to LSDB. */
+	ospf_lsdb_add(lsdb, lsa);
+	lsa->lsdb = lsdb;
+
+	/* Do LSA specific installation process. */
+	switch (lsa->data->type) {
+	case OSPF_ROUTER_LSA:
+		new = ospf_router_lsa_install(ospf, lsa, rt_recalc);
+		break;
+	case OSPF_NETWORK_LSA:
+		assert(oi);
+		new = ospf_network_lsa_install(ospf, oi, lsa, rt_recalc);
+		break;
+	case OSPF_SUMMARY_LSA:
+		new = ospf_summary_lsa_install(ospf, lsa, rt_recalc);
+		break;
+	case OSPF_ASBR_SUMMARY_LSA:
+		new = ospf_summary_asbr_lsa_install(ospf, lsa, rt_recalc);
+		break;
+	case OSPF_AS_EXTERNAL_LSA:
+		new = ospf_external_lsa_install(ospf, lsa, rt_recalc);
+		break;
+	case OSPF_OPAQUE_LINK_LSA:
+		if (IS_LSA_SELF(lsa))
+			lsa->oi = oi; /* Specify outgoing ospf-interface for
+					 this LSA. */
+		else {
+			/* Incoming "oi" for this LSA has set at LSUpd
+			 * reception. */
+		}
+	/* Fallthrough */
+	case OSPF_OPAQUE_AREA_LSA:
+	case OSPF_OPAQUE_AS_LSA:
+		new = ospf_opaque_lsa_install(lsa, rt_recalc);
+		break;
+	case OSPF_AS_NSSA_LSA:
+		new = ospf_external_lsa_install(ospf, lsa, rt_recalc);
+	default: /* type-6,8,9....nothing special */
+		break;
+	}
+
+	if (new == NULL)
+		return new; /* Installation failed, cannot proceed further --
+			       endo. */
+
+	/* Debug logs. */
+	if (IS_DEBUG_OSPF(lsa, LSA_INSTALL)) {
+		switch (lsa->data->type) {
+		case OSPF_AS_EXTERNAL_LSA:
+		case OSPF_OPAQUE_AS_LSA:
+		case OSPF_AS_NSSA_LSA:
+			zlog_debug("LSA[%s]: Install %s", dump_lsa_key(new),
+				   lookup_msg(ospf_lsa_type_msg,
+					      new->data->type, NULL));
+			break;
+		default:
+			zlog_debug("LSA[%s]: Install %s to Area %pI4",
+				   dump_lsa_key(new),
+				   lookup_msg(ospf_lsa_type_msg,
+					      new->data->type, NULL),
+				   &new->area->area_id);
+			break;
+		}
+	}
+
+	/*
+	   If received LSA' ls_age is MaxAge, or lsa is being prematurely aged
+	   (it's getting flushed out of the area), set LSA on MaxAge LSA list.
+	 */
+	if (IS_LSA_MAXAGE(new)) {
+		if (IS_DEBUG_OSPF(lsa, LSA_INSTALL))
+			zlog_debug("LSA[%s]: Install LSA %p, MaxAge",
+				   dump_lsa_key(new), lsa);
+		ospf_lsa_maxage(ospf, lsa);
+	}
+
+	return new;
+}
+
+
+int ospf_check_nbr_status(struct ospf *ospf)
+{
+	struct listnode *node, *nnode;
+	struct ospf_interface *oi;
+
+	for (ALL_LIST_ELEMENTS(ospf->oiflist, node, nnode, oi)) {
+		struct route_node *rn;
+		struct ospf_neighbor *nbr;
+
+		if (ospf_if_is_enable(oi))
+			for (rn = route_top(oi->nbrs); rn; rn = route_next(rn))
+				if ((nbr = rn->info) != NULL)
+					if (nbr->state == NSM_Exchange
+					    || nbr->state == NSM_Loading) {
+						route_unlock_node(rn);
+						return 0;
+					}
+	}
+
+	return 1;
+}
+
+
+void ospf_maxage_lsa_remover(struct event *thread)
+{
+	struct ospf *ospf = EVENT_ARG(thread);
+	struct ospf_lsa *lsa, *old;
+	struct route_node *rn;
+	int reschedule = 0;
+
+	ospf->t_maxage = NULL;
+
+	if (IS_DEBUG_OSPF(lsa, LSA_FLOODING))
+		zlog_debug("LSA[MaxAge]: remover Start");
+
+	reschedule = !ospf_check_nbr_status(ospf);
+
+	if (!reschedule)
+		for (rn = route_top(ospf->maxage_lsa); rn;
+		     rn = route_next(rn)) {
+			if ((lsa = rn->info) == NULL) {
+				continue;
+			}
+
+			/* There is at least one neighbor from which we still
+			 * await an ack
+			 * for that LSA, so we are not allowed to remove it from
+			 * our lsdb yet
+			 * as per RFC 2328 section 14 para 4 a) */
+			if (lsa->retransmit_counter > 0) {
+				reschedule = 1;
+				continue;
+			}
+
+			/* TODO: maybe convert this function to a work-queue */
+			if (event_should_yield(thread)) {
+				OSPF_TIMER_ON(ospf->t_maxage,
+					      ospf_maxage_lsa_remover, 0);
+				route_unlock_node(
+					rn); /* route_top/route_next */
+				return;
+			}
+
+			/* Remove LSA from the LSDB */
+			if (IS_LSA_SELF(lsa))
+				if (IS_DEBUG_OSPF(lsa, LSA_FLOODING))
+					zlog_debug(
+						"LSA[Type%d:%pI4]: LSA 0x%lx is self-originated: ",
+						lsa->data->type,
+						&lsa->data->id,
+						(unsigned long)lsa);
+
+			if (IS_DEBUG_OSPF(lsa, LSA_FLOODING))
+				zlog_debug(
+					"LSA[%s]: MaxAge LSA removed from list",
+					dump_lsa_key(lsa));
+
+			if (CHECK_FLAG(lsa->flags, OSPF_LSA_PREMATURE_AGE)) {
+				if (IS_DEBUG_OSPF(lsa, LSA_FLOODING))
+					zlog_debug(
+						"originating new lsa for lsa %p",
+						lsa);
+				ospf_lsa_refresh(ospf, lsa);
+			}
+
+			/* Remove from lsdb. */
+			if (lsa->lsdb) {
+				old = ospf_lsdb_lookup(lsa->lsdb, lsa);
+				/* The max age LSA here must be the same
+				 * as the LSA in LSDB
+				 */
+				if (old != lsa) {
+					flog_err(EC_OSPF_LSA_MISSING,
+						 "%s: LSA[%s]: LSA not in LSDB",
+						 __func__, dump_lsa_key(lsa));
+
+					continue;
+				}
+				ospf_discard_from_db(ospf, lsa->lsdb, lsa);
+				ospf_lsdb_delete(lsa->lsdb, lsa);
+			} else {
+				if (IS_DEBUG_OSPF(lsa, LSA_FLOODING))
+					zlog_debug(
+						"%s: LSA[%s]: No associated LSDB!",
+						__func__, dump_lsa_key(lsa));
+			}
+		}
+
+	/*    A MaxAge LSA must be removed immediately from the router's link
+	      state database as soon as both a) it is no longer contained on any
+	      neighbor Link state retransmission lists and b) none of the
+	   router's
+	      neighbors are in states Exchange or Loading. */
+	if (reschedule)
+		OSPF_TIMER_ON(ospf->t_maxage, ospf_maxage_lsa_remover,
+			      ospf->maxage_delay);
+}
+
+/* This function checks whether an LSA with initial sequence number should be
+ *  originated after a wrap in sequence number
+ */
+void ospf_check_and_gen_init_seq_lsa(struct ospf_interface *oi,
+				     struct ospf_lsa *recv_lsa)
+{
+	struct ospf_lsa *lsa = NULL;
+	struct ospf *ospf = oi->ospf;
+
+	lsa = ospf_lsa_lookup_by_header(oi->area, recv_lsa->data);
+
+	if ((lsa == NULL) || (!CHECK_FLAG(lsa->flags, OSPF_LSA_PREMATURE_AGE))
+	    || (lsa->retransmit_counter != 0)) {
+		if (IS_DEBUG_OSPF(lsa, LSA))
+			zlog_debug(
+				"Do not generate LSA with initial seqence number.");
+		return;
+	}
+
+	ospf_lsa_maxage_delete(ospf, lsa);
+
+	lsa->data->ls_seqnum = lsa_seqnum_increment(lsa);
+
+	ospf_lsa_refresh(ospf, lsa);
+}
+
+void ospf_lsa_maxage_delete(struct ospf *ospf, struct ospf_lsa *lsa)
+{
+	struct route_node *rn;
+	struct prefix lsa_prefix;
+
+	memset(&lsa_prefix, 0, sizeof(lsa_prefix));
+	lsa_prefix.family = AF_UNSPEC;
+	lsa_prefix.prefixlen = sizeof(lsa_prefix.u.ptr) * CHAR_BIT;
+	lsa_prefix.u.ptr = (uintptr_t)lsa;
+
+	if ((rn = route_node_lookup(ospf->maxage_lsa, &lsa_prefix))) {
+		if (rn->info == lsa) {
+			UNSET_FLAG(lsa->flags, OSPF_LSA_IN_MAXAGE);
+			ospf_lsa_unlock(&lsa); /* maxage_lsa */
+			rn->info = NULL;
+			route_unlock_node(
+				rn); /* unlock node because lsa is deleted */
+		}
+		route_unlock_node(rn); /* route_node_lookup */
+	} else {
+		if (IS_DEBUG_OSPF_EVENT)
+			zlog_debug("%s: lsa %s is not found in maxage db.",
+				   __func__, dump_lsa_key(lsa));
+	}
+}
+
+/* Add LSA onto the MaxAge list, and schedule for removal.
+ * This does *not* lead to the LSA being flooded, that must be taken
+ * care of elsewhere, see, e.g., ospf_lsa_flush* (which are callers of this
+ * function).
+ */
+void ospf_lsa_maxage(struct ospf *ospf, struct ospf_lsa *lsa)
+{
+	struct prefix lsa_prefix;
+	struct route_node *rn;
+
+	/* When we saw a MaxAge LSA flooded to us, we put it on the list
+	   and schedule the MaxAge LSA remover. */
+	if (CHECK_FLAG(lsa->flags, OSPF_LSA_IN_MAXAGE)) {
+		if (IS_DEBUG_OSPF(lsa, LSA_FLOODING))
+			zlog_debug(
+				"LSA[%s]: %p already exists on MaxAge LSA list",
+				dump_lsa_key(lsa), lsa);
+		return;
+	}
+
+	memset(&lsa_prefix, 0, sizeof(lsa_prefix));
+	lsa_prefix.family = AF_UNSPEC;
+	lsa_prefix.prefixlen = sizeof(lsa_prefix.u.ptr) * CHAR_BIT;
+	lsa_prefix.u.ptr = (uintptr_t)lsa;
+
+	rn = route_node_get(ospf->maxage_lsa, &lsa_prefix);
+	if (rn->info != NULL) {
+		if (IS_DEBUG_OSPF(lsa, LSA_FLOODING))
+			zlog_debug(
+				   "LSA[%s]: found LSA (%p) in table for LSA %p %d",
+				   dump_lsa_key(lsa), rn->info,
+				   (void *)lsa, lsa_prefix.prefixlen);
+		route_unlock_node(rn);
+	} else {
+		rn->info = ospf_lsa_lock(lsa);
+		SET_FLAG(lsa->flags, OSPF_LSA_IN_MAXAGE);
+	}
+
+	if (IS_DEBUG_OSPF(lsa, LSA_FLOODING))
+		zlog_debug("LSA[%s]: MaxAge LSA remover scheduled.",
+			   dump_lsa_key(lsa));
+
+	OSPF_TIMER_ON(ospf->t_maxage, ospf_maxage_lsa_remover,
+		      ospf->maxage_delay);
+}
+
+static int ospf_lsa_maxage_walker_remover(struct ospf *ospf,
+					  struct ospf_lsa *lsa)
+{
+	/* Stay away from any Local Translated Type-7 LSAs */
+	if (CHECK_FLAG(lsa->flags, OSPF_LSA_LOCAL_XLT))
+		return 0;
+
+	if (IS_LSA_MAXAGE(lsa))
+		/* Self-originated LSAs should NOT time-out instead,
+		   they're flushed and submitted to the max_age list explicitly.
+		   */
+		if (!ospf_lsa_is_self_originated(ospf, lsa)) {
+			if (IS_DEBUG_OSPF(lsa, LSA_FLOODING))
+				zlog_debug("LSA[%s]: is MaxAge",
+					   dump_lsa_key(lsa));
+
+			switch (lsa->data->type) {
+			case OSPF_OPAQUE_LINK_LSA:
+			case OSPF_OPAQUE_AREA_LSA:
+			case OSPF_OPAQUE_AS_LSA:
+				/*
+				 * As a general rule, whenever network topology
+				 * has changed
+				 * (due to an LSA removal in this case), routing
+				 * recalculation
+				 * should be triggered. However, this is not
+				 * true for opaque
+				 * LSAs. Even if an opaque LSA instance is going
+				 * to be removed
+				 * from the routing domain, it does not mean a
+				 * change in network
+				 * topology, and thus, routing recalculation is
+				 * not needed here.
+				 */
+				break;
+			case OSPF_AS_EXTERNAL_LSA:
+			case OSPF_AS_NSSA_LSA:
+				ospf_ase_incremental_update(ospf, lsa);
+				break;
+			default:
+				ospf_spf_calculate_schedule(ospf,
+							    SPF_FLAG_MAXAGE);
+				break;
+			}
+			ospf_lsa_maxage(ospf, lsa);
+		}
+
+	if (IS_LSA_MAXAGE(lsa) && !ospf_lsa_is_self_originated(ospf, lsa))
+		if (LS_AGE(lsa) > OSPF_LSA_MAXAGE + 30)
+			printf("Eek! Shouldn't happen!\n");
+
+	return 0;
+}
+
+/* Periodical check of MaxAge LSA. */
+void ospf_lsa_maxage_walker(struct event *thread)
+{
+	struct ospf *ospf = EVENT_ARG(thread);
+	struct route_node *rn;
+	struct ospf_lsa *lsa;
+	struct ospf_area *area;
+	struct listnode *node, *nnode;
+
+	ospf->t_maxage_walker = NULL;
+
+	for (ALL_LIST_ELEMENTS(ospf->areas, node, nnode, area)) {
+		LSDB_LOOP (ROUTER_LSDB(area), rn, lsa)
+			ospf_lsa_maxage_walker_remover(ospf, lsa);
+		LSDB_LOOP (NETWORK_LSDB(area), rn, lsa)
+			ospf_lsa_maxage_walker_remover(ospf, lsa);
+		LSDB_LOOP (SUMMARY_LSDB(area), rn, lsa)
+			ospf_lsa_maxage_walker_remover(ospf, lsa);
+		LSDB_LOOP (ASBR_SUMMARY_LSDB(area), rn, lsa)
+			ospf_lsa_maxage_walker_remover(ospf, lsa);
+		LSDB_LOOP (OPAQUE_AREA_LSDB(area), rn, lsa)
+			ospf_lsa_maxage_walker_remover(ospf, lsa);
+		LSDB_LOOP (OPAQUE_LINK_LSDB(area), rn, lsa)
+			ospf_lsa_maxage_walker_remover(ospf, lsa);
+		LSDB_LOOP (NSSA_LSDB(area), rn, lsa)
+			ospf_lsa_maxage_walker_remover(ospf, lsa);
+	}
+
+	/* for AS-external-LSAs. */
+	if (ospf->lsdb) {
+		LSDB_LOOP (EXTERNAL_LSDB(ospf), rn, lsa)
+			ospf_lsa_maxage_walker_remover(ospf, lsa);
+		LSDB_LOOP (OPAQUE_AS_LSDB(ospf), rn, lsa)
+			ospf_lsa_maxage_walker_remover(ospf, lsa);
+	}
+
+	OSPF_TIMER_ON(ospf->t_maxage_walker, ospf_lsa_maxage_walker,
+		      OSPF_LSA_MAXAGE_CHECK_INTERVAL);
+}
+
+struct ospf_lsa *ospf_lsa_lookup_by_prefix(struct ospf_lsdb *lsdb, uint8_t type,
+					   struct prefix_ipv4 *p,
+					   struct in_addr router_id)
+{
+	struct ospf_lsa *lsa;
+	struct in_addr mask, id;
+	struct lsa_header_mask {
+		struct lsa_header header;
+		struct in_addr mask;
+	} * hmask;
+
+	lsa = ospf_lsdb_lookup_by_id(lsdb, type, p->prefix, router_id);
+	if (lsa == NULL)
+		return NULL;
+
+	masklen2ip(p->prefixlen, &mask);
+
+	hmask = (struct lsa_header_mask *)lsa->data;
+
+	if (mask.s_addr != hmask->mask.s_addr) {
+		id.s_addr = p->prefix.s_addr | (~mask.s_addr);
+		lsa = ospf_lsdb_lookup_by_id(lsdb, type, id, router_id);
+		if (!lsa)
+			return NULL;
+	}
+
+	return lsa;
+}
+
+struct ospf_lsa *ospf_lsa_lookup(struct ospf *ospf, struct ospf_area *area,
+				 uint32_t type, struct in_addr id,
+				 struct in_addr adv_router)
+{
+	if (!ospf)
+		return NULL;
+
+	switch (type) {
+	case OSPF_ROUTER_LSA:
+	case OSPF_NETWORK_LSA:
+	case OSPF_SUMMARY_LSA:
+	case OSPF_ASBR_SUMMARY_LSA:
+	case OSPF_AS_NSSA_LSA:
+	case OSPF_OPAQUE_LINK_LSA:
+	case OSPF_OPAQUE_AREA_LSA:
+		return ospf_lsdb_lookup_by_id(area->lsdb, type, id, adv_router);
+	case OSPF_AS_EXTERNAL_LSA:
+	case OSPF_OPAQUE_AS_LSA:
+		return ospf_lsdb_lookup_by_id(ospf->lsdb, type, id, adv_router);
+	default:
+		break;
+	}
+
+	return NULL;
+}
+
+struct ospf_lsa *ospf_lsa_lookup_by_id(struct ospf_area *area, uint32_t type,
+				       struct in_addr id)
+{
+	struct ospf_lsa *lsa;
+	struct route_node *rn;
+
+	switch (type) {
+	case OSPF_ROUTER_LSA:
+		return ospf_lsdb_lookup_by_id(area->lsdb, type, id, id);
+	case OSPF_NETWORK_LSA:
+		for (rn = route_top(NETWORK_LSDB(area)); rn;
+		     rn = route_next(rn))
+			if ((lsa = rn->info))
+				if (IPV4_ADDR_SAME(&lsa->data->id, &id)) {
+					route_unlock_node(rn);
+					return lsa;
+				}
+		break;
+	case OSPF_SUMMARY_LSA:
+	case OSPF_ASBR_SUMMARY_LSA:
+		/* Currently not used. */
+		assert(1);
+		return ospf_lsdb_lookup_by_id(area->lsdb, type, id, id);
+	case OSPF_AS_EXTERNAL_LSA:
+	case OSPF_AS_NSSA_LSA:
+	case OSPF_OPAQUE_LINK_LSA:
+	case OSPF_OPAQUE_AREA_LSA:
+	case OSPF_OPAQUE_AS_LSA:
+		/* Currently not used. */
+		break;
+	default:
+		break;
+	}
+
+	return NULL;
+}
+
+struct ospf_lsa *ospf_lsa_lookup_by_header(struct ospf_area *area,
+					   struct lsa_header *lsah)
+{
+	struct ospf_lsa *match;
+
+	/*
+	 * Strictly speaking, the LSA-ID field for Opaque-LSAs (type-9/10/11)
+	 * is redefined to have two subfields; opaque-type and opaque-id.
+	 * However, it is harmless to treat the two sub fields together, as if
+	 * they two were forming a unique LSA-ID.
+	 */
+
+	match = ospf_lsa_lookup(area->ospf, area, lsah->type, lsah->id,
+				lsah->adv_router);
+
+	if (match == NULL)
+		if (IS_DEBUG_OSPF(lsa, LSA) == OSPF_DEBUG_LSA)
+			zlog_debug("LSA[Type%d:%pI4]: Lookup by header, NO MATCH",
+				   lsah->type, &lsah->id);
+
+	return match;
+}
+
+/* return +n, l1 is more recent.
+   return -n, l2 is more recent.
+   return 0, l1 and l2 is identical. */
+int ospf_lsa_more_recent(struct ospf_lsa *l1, struct ospf_lsa *l2)
+{
+	int r;
+	int x, y;
+
+	if (l1 == NULL && l2 == NULL)
+		return 0;
+	if (l1 == NULL)
+		return -1;
+	if (l2 == NULL)
+		return 1;
+
+	/* compare LS sequence number. */
+	x = (int)ntohl(l1->data->ls_seqnum);
+	y = (int)ntohl(l2->data->ls_seqnum);
+	if (x > y)
+		return 1;
+	if (x < y)
+		return -1;
+
+	/* compare LS checksum. */
+	r = ntohs(l1->data->checksum) - ntohs(l2->data->checksum);
+	if (r)
+		return r;
+
+	/* compare LS age. */
+	if (IS_LSA_MAXAGE(l1) && !IS_LSA_MAXAGE(l2))
+		return 1;
+	else if (!IS_LSA_MAXAGE(l1) && IS_LSA_MAXAGE(l2))
+		return -1;
+
+	/* compare LS age with MaxAgeDiff. */
+	if (LS_AGE(l1) - LS_AGE(l2) > OSPF_LSA_MAXAGE_DIFF)
+		return -1;
+	else if (LS_AGE(l2) - LS_AGE(l1) > OSPF_LSA_MAXAGE_DIFF)
+		return 1;
+
+	/* LSAs are identical. */
+	return 0;
+}
+
+/*
+ * Check if two LSAs are different.
+ *
+ * l1
+ *    The first LSA to compare.
+ *
+ * l2
+ *    The second LSA to compare.
+ *
+ * ignore_rcvd_flag
+ *    When set to true, ignore whether the LSAs were received from the network
+ *    or not. This parameter should be set to true when checking for topology
+ *    changes as part of the Graceful Restart helper neighbor procedures.
+ *
+ * Returns:
+ *    true if the LSAs are different, false otherwise.
+ */
+int ospf_lsa_different(struct ospf_lsa *l1, struct ospf_lsa *l2,
+		       bool ignore_rcvd_flag)
+{
+	char *p1, *p2;
+	assert(l1);
+	assert(l2);
+	assert(l1->data);
+	assert(l2->data);
+
+	if (l1->data->options != l2->data->options)
+		return 1;
+
+	if (IS_LSA_MAXAGE(l1) && !IS_LSA_MAXAGE(l2))
+		return 1;
+
+	if (IS_LSA_MAXAGE(l2) && !IS_LSA_MAXAGE(l1))
+		return 1;
+
+	if (l1->size != l2->size)
+		return 1;
+
+	if (l1->size == 0)
+		return 1;
+
+	if (!ignore_rcvd_flag
+	    && CHECK_FLAG((l1->flags ^ l2->flags), OSPF_LSA_RECEIVED))
+		return 1; /* May be a stale LSA in the LSBD */
+
+	if (l1->size == OSPF_LSA_HEADER_SIZE)
+		return 0; /* nothing to compare */
+
+	p1 = (char *)l1->data;
+	p2 = (char *)l2->data;
+
+	if (memcmp(p1 + OSPF_LSA_HEADER_SIZE, p2 + OSPF_LSA_HEADER_SIZE,
+		   l1->size - OSPF_LSA_HEADER_SIZE)
+	    != 0)
+		return 1;
+
+	return 0;
+}
+
+int ospf_lsa_flush_schedule(struct ospf *ospf, struct ospf_lsa *lsa)
+{
+	if (lsa == NULL || !IS_LSA_SELF(lsa))
+		return 0;
+
+	if (IS_DEBUG_OSPF_EVENT)
+		zlog_debug(
+			"LSA[Type%d:%pI4]: Schedule self-originated LSA to FLUSH",
+			lsa->data->type, &lsa->data->id);
+
+	/* Force given lsa's age to MaxAge. */
+	lsa->data->ls_age = htons(OSPF_LSA_MAXAGE);
+
+	switch (lsa->data->type) {
+	/* Opaque wants to be notified of flushes */
+	case OSPF_OPAQUE_LINK_LSA:
+	case OSPF_OPAQUE_AREA_LSA:
+	case OSPF_OPAQUE_AS_LSA:
+		ospf_opaque_lsa_refresh(lsa);
+		break;
+	default:
+		ospf_refresher_unregister_lsa(ospf, lsa);
+		ospf_lsa_flush(ospf, lsa);
+		break;
+	}
+
+	return 0;
+}
+
+void ospf_flush_self_originated_lsas_now(struct ospf *ospf)
+{
+	struct listnode *node, *nnode;
+	struct listnode *node2, *nnode2;
+	struct ospf_area *area;
+	struct ospf_interface *oi;
+	struct ospf_lsa *lsa;
+	struct route_node *rn;
+	struct ospf_if_params *oip;
+	int need_to_flush_ase = 0;
+
+	ospf->inst_shutdown = 1;
+
+	for (ALL_LIST_ELEMENTS(ospf->areas, node, nnode, area)) {
+		if ((lsa = area->router_lsa_self) != NULL) {
+			if (IS_DEBUG_OSPF_EVENT)
+				zlog_debug(
+					"LSA[Type%d:%pI4]: Schedule self-originated LSA to FLUSH",
+					lsa->data->type,
+					&lsa->data->id);
+
+			ospf_refresher_unregister_lsa(ospf, lsa);
+			ospf_lsa_flush_area(lsa, area);
+			ospf_lsa_unlock(&area->router_lsa_self);
+			area->router_lsa_self = NULL;
+		}
+
+		for (ALL_LIST_ELEMENTS(area->oiflist, node2, nnode2, oi)) {
+			if ((lsa = oi->network_lsa_self) != NULL
+			    && oi->state == ISM_DR && oi->full_nbrs > 0) {
+				if (IS_DEBUG_OSPF_EVENT)
+					zlog_debug(
+						"LSA[Type%d:%pI4]: Schedule self-originated LSA to FLUSH",
+						lsa->data->type,
+						&lsa->data->id);
+
+				ospf_refresher_unregister_lsa(
+					ospf, oi->network_lsa_self);
+				ospf_lsa_flush_area(oi->network_lsa_self, area);
+				ospf_lsa_unlock(&oi->network_lsa_self);
+				oi->network_lsa_self = NULL;
+
+				oip = ospf_lookup_if_params(
+					oi->ifp, oi->address->u.prefix4);
+				if (oip)
+					oip->network_lsa_seqnum = htonl(
+						OSPF_INVALID_SEQUENCE_NUMBER);
+			}
+
+			if (oi->type != OSPF_IFTYPE_VIRTUALLINK
+			    && area->external_routing == OSPF_AREA_DEFAULT)
+				need_to_flush_ase = 1;
+		}
+
+		LSDB_LOOP (SUMMARY_LSDB(area), rn, lsa)
+			ospf_lsa_flush_schedule(ospf, lsa);
+		LSDB_LOOP (ASBR_SUMMARY_LSDB(area), rn, lsa)
+			ospf_lsa_flush_schedule(ospf, lsa);
+		LSDB_LOOP (OPAQUE_LINK_LSDB(area), rn, lsa)
+			ospf_lsa_flush_schedule(ospf, lsa);
+		LSDB_LOOP (OPAQUE_AREA_LSDB(area), rn, lsa)
+			ospf_lsa_flush_schedule(ospf, lsa);
+	}
+
+	if (need_to_flush_ase) {
+		LSDB_LOOP (EXTERNAL_LSDB(ospf), rn, lsa)
+			ospf_lsa_flush_schedule(ospf, lsa);
+		LSDB_LOOP (OPAQUE_AS_LSDB(ospf), rn, lsa)
+			ospf_lsa_flush_schedule(ospf, lsa);
+	}
+
+	/*
+	 * Make sure that the MaxAge LSA remover is executed immediately,
+	 * without conflicting to other threads.
+	 */
+	if (ospf->t_maxage != NULL) {
+		EVENT_OFF(ospf->t_maxage);
+		event_execute(master, ospf_maxage_lsa_remover, ospf, 0, NULL);
+	}
+
+	return;
+}
+
+/** @brief Function to refresh all the self originated
+ *	   LSAs for area, when FR state change happens.
+ *  @param area pointer.
+ *  @return Void.
+ */
+void ospf_refresh_area_self_lsas(struct ospf_area *area)
+{
+	struct listnode *node2;
+	struct listnode *nnode2;
+	struct ospf_interface *oi;
+	struct route_node *rn;
+	struct ospf_lsa *lsa;
+
+	if (!area)
+		return;
+
+	if (area->router_lsa_self)
+		ospf_lsa_refresh(area->ospf, area->router_lsa_self);
+
+	for (ALL_LIST_ELEMENTS(area->oiflist, node2, nnode2, oi))
+		if (oi->network_lsa_self)
+			ospf_lsa_refresh(oi->ospf, oi->network_lsa_self);
+
+	LSDB_LOOP (SUMMARY_LSDB(area), rn, lsa)
+		if (IS_LSA_SELF(lsa))
+			ospf_lsa_refresh(area->ospf, lsa);
+	LSDB_LOOP (ASBR_SUMMARY_LSDB(area), rn, lsa)
+		if (IS_LSA_SELF(lsa))
+			ospf_lsa_refresh(area->ospf, lsa);
+	LSDB_LOOP (OPAQUE_LINK_LSDB(area), rn, lsa)
+		if (IS_LSA_SELF(lsa))
+			ospf_lsa_refresh(area->ospf, lsa);
+	LSDB_LOOP (OPAQUE_AREA_LSDB(area), rn, lsa)
+		if (IS_LSA_SELF(lsa))
+			ospf_lsa_refresh(area->ospf, lsa);
+	LSDB_LOOP (EXTERNAL_LSDB(area->ospf), rn, lsa)
+		if (IS_LSA_SELF(lsa))
+			ospf_lsa_refresh(area->ospf, lsa);
+	LSDB_LOOP (OPAQUE_AS_LSDB(area->ospf), rn, lsa)
+		if (IS_LSA_SELF(lsa))
+			ospf_lsa_refresh(area->ospf, lsa);
+}
+
+/* If there is self-originated LSA, then return 1, otherwise return 0. */
+/* An interface-independent version of ospf_lsa_is_self_originated */
+int ospf_lsa_is_self_originated(struct ospf *ospf, struct ospf_lsa *lsa)
+{
+	struct listnode *node;
+	struct ospf_interface *oi;
+
+	/* This LSA is already checked. */
+	if (CHECK_FLAG(lsa->flags, OSPF_LSA_SELF_CHECKED))
+		return IS_LSA_SELF(lsa);
+
+	/* Make sure LSA is self-checked. */
+	SET_FLAG(lsa->flags, OSPF_LSA_SELF_CHECKED);
+
+	/* AdvRouter and Router ID is the same. */
+	if (IPV4_ADDR_SAME(&lsa->data->adv_router, &ospf->router_id))
+		SET_FLAG(lsa->flags, OSPF_LSA_SELF);
+
+	/* LSA is router-LSA. */
+	else if (lsa->data->type == OSPF_ROUTER_LSA
+		 && IPV4_ADDR_SAME(&lsa->data->id, &ospf->router_id))
+		SET_FLAG(lsa->flags, OSPF_LSA_SELF);
+
+	/* LSA is network-LSA.  Compare Link ID with all interfaces. */
+	else if (lsa->data->type == OSPF_NETWORK_LSA)
+		for (ALL_LIST_ELEMENTS_RO(ospf->oiflist, node, oi)) {
+			/* Ignore virtual link. */
+			if (oi->type != OSPF_IFTYPE_VIRTUALLINK)
+				if (oi->address->family == AF_INET)
+					if (IPV4_ADDR_SAME(
+						    &lsa->data->id,
+						    &oi->address->u.prefix4)) {
+						/* to make it easier later */
+						SET_FLAG(lsa->flags,
+							 OSPF_LSA_SELF);
+						return IS_LSA_SELF(lsa);
+					}
+		}
+
+	return IS_LSA_SELF(lsa);
+}
+
+/* Get unique Link State ID. */
+enum lsid_status ospf_lsa_unique_id(struct ospf *ospf, struct ospf_lsdb *lsdb,
+				    uint8_t type, struct prefix_ipv4 *p,
+				    struct in_addr *id)
+{
+	struct ospf_lsa *lsa;
+	struct in_addr mask;
+
+	*id = p->prefix;
+
+	/* Check existence of LSA instance. */
+	lsa = ospf_lsdb_lookup_by_id(lsdb, type, *id, ospf->router_id);
+	if (lsa) {
+		struct as_external_lsa *al =
+			(struct as_external_lsa *)lsa->data;
+		/* Ref rfc2328,Appendex E.1
+		 * If router already originated the external lsa with lsid
+		 * as the current prefix, and the masklens are same then
+		 * terminate the LSID algorithem.
+		 */
+		if (ip_masklen(al->mask) == p->prefixlen) {
+			if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+				zlog_debug(
+					"%s: Can't get Link State ID for %pFX",
+					__func__, p);
+			/*	  id.s_addr = 0; */
+			id->s_addr = 0xffffffff;
+			return LSID_NOT_AVAILABLE;
+		} else if (ip_masklen(al->mask) < p->prefixlen) {
+			/* Ref rfc2328,Appendex E.2
+			 * the current prefix masklen is greater than the
+			 * existing LSA, then generate the Link state ID,
+			 * by setting all host bits in prefix addressa and
+			 * originate.
+			 *
+			 * Eg: 1st Route : 10.0.0.0/16 - LSID:10.0.0.0
+			 *     2nd Route : 10.0.0.0/24 - LSID:10.0.0.255
+			 */
+			masklen2ip(p->prefixlen, &mask);
+
+			id->s_addr = p->prefix.s_addr | (~mask.s_addr);
+			lsa = ospf_lsdb_lookup_by_id(ospf->lsdb, type, *id,
+						     ospf->router_id);
+			if (lsa) {
+				if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+					zlog_debug(
+						"%s: Can't get Link State ID for %pFX",
+						__func__, p);
+				id->s_addr = 0xffffffff;
+				return LSID_NOT_AVAILABLE;
+			}
+		} else {
+			/* Ref rfc2328,Appendex E.3
+			 * the current prefix masklen is lesser than the
+			 * existing LSA,then the originated LSA has to be
+			 * refreshed by modifying masklen, cost and tag.
+			 * Originate the old route info with new LSID by
+			 * setting the host bits in prefix address.
+			 *
+			 * Eg: 1st Route : 10.0.0.0/24 - LSID:10.0.0.0
+			 *     2nd Route : 10.0.0.0/16 - ?
+			 * Since 2nd route mask len is less than firstone
+			 * LSID has to be changed.
+			 *     1st route LSID:10.0.0.255
+			 *     2nd route LSID:10.0.0.0
+			 */
+			id->s_addr = lsa->data->id.s_addr | (~al->mask.s_addr);
+			lsa = ospf_lsdb_lookup_by_id(ospf->lsdb, type, *id,
+						     ospf->router_id);
+			if (lsa && (ip_masklen(al->mask) != IPV4_MAX_BITLEN)) {
+				if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
+					zlog_debug(
+						"%s: Can't get Link State ID for %pFX",
+						__func__, p);
+				id->s_addr = 0xffffffff;
+				return LSID_NOT_AVAILABLE;
+			}
+			return LSID_CHANGE;
+		}
+	}
+
+	return LSID_AVAILABLE;
+}
+
+
+#define LSA_ACTION_FLOOD_AREA 1
+#define LSA_ACTION_FLUSH_AREA 2
+
+struct lsa_action {
+	uint8_t action;
+	struct ospf_area *area;
+	struct ospf_lsa *lsa;
+};
+
+static void ospf_lsa_action(struct event *t)
+{
+	struct lsa_action *data;
+
+	data = EVENT_ARG(t);
+
+	if (IS_DEBUG_OSPF(lsa, LSA) == OSPF_DEBUG_LSA)
+		zlog_debug("LSA[Action]: Performing scheduled LSA action: %d",
+			   data->action);
+
+	switch (data->action) {
+	case LSA_ACTION_FLOOD_AREA:
+		ospf_flood_through_area(data->area, NULL, data->lsa);
+		break;
+	case LSA_ACTION_FLUSH_AREA:
+		ospf_lsa_flush_area(data->lsa, data->area);
+		break;
+	}
+
+	ospf_lsa_unlock(&data->lsa); /* Message */
+	XFREE(MTYPE_OSPF_MESSAGE, data);
+}
+
+void ospf_schedule_lsa_flood_area(struct ospf_area *area, struct ospf_lsa *lsa)
+{
+	struct lsa_action *data;
+
+	data = XCALLOC(MTYPE_OSPF_MESSAGE, sizeof(struct lsa_action));
+	data->action = LSA_ACTION_FLOOD_AREA;
+	data->area = area;
+	data->lsa = ospf_lsa_lock(lsa); /* Message / Flood area */
+
+	event_add_event(master, ospf_lsa_action, data, 0, NULL);
+}
+
+void ospf_schedule_lsa_flush_area(struct ospf_area *area, struct ospf_lsa *lsa)
+{
+	struct lsa_action *data;
+
+	data = XCALLOC(MTYPE_OSPF_MESSAGE, sizeof(struct lsa_action));
+	data->action = LSA_ACTION_FLUSH_AREA;
+	data->area = area;
+	data->lsa = ospf_lsa_lock(lsa); /* Message / Flush area */
+
+	event_add_event(master, ospf_lsa_action, data, 0, NULL);
+}
+
+
+/* LSA Refreshment functions. */
+struct ospf_lsa *ospf_lsa_refresh(struct ospf *ospf, struct ospf_lsa *lsa)
+{
+	struct external_info *ei;
+	struct ospf_external_aggr_rt *aggr;
+	struct ospf_lsa *new = NULL;
+	struct as_external_lsa *al;
+	struct prefix_ipv4 p;
+
+	assert(CHECK_FLAG(lsa->flags, OSPF_LSA_SELF));
+	assert(IS_LSA_SELF(lsa));
+	assert(lsa->lock > 0);
+
+	switch (lsa->data->type) {
+	/* Router and Network LSAs are processed differently. */
+	case OSPF_ROUTER_LSA:
+		new = ospf_router_lsa_refresh(lsa);
+		break;
+	case OSPF_NETWORK_LSA:
+		new = ospf_network_lsa_refresh(lsa);
+		break;
+	case OSPF_SUMMARY_LSA:
+		new = ospf_summary_lsa_refresh(ospf, lsa);
+		break;
+	case OSPF_ASBR_SUMMARY_LSA:
+		new = ospf_summary_asbr_lsa_refresh(ospf, lsa);
+		break;
+	case OSPF_AS_EXTERNAL_LSA:
+		/* Translated from NSSA Type-5s are refreshed when
+		 * from refresh of Type-7 - do not refresh these directly.
+		 */
+
+		al = (struct as_external_lsa *)lsa->data;
+		p.family = AF_INET;
+		p.prefixlen = ip_masklen(al->mask);
+		p.prefix = lsa->data->id;
+
+		if (CHECK_FLAG(lsa->flags, OSPF_LSA_LOCAL_XLT))
+			break;
+		ei = ospf_external_info_check(ospf, lsa);
+		if (ei)
+			new = ospf_external_lsa_refresh(
+				ospf, lsa, ei, LSA_REFRESH_FORCE, false);
+		else {
+			aggr = (struct ospf_external_aggr_rt *)
+				ospf_extrenal_aggregator_lookup(ospf, &p);
+			if (aggr) {
+				struct external_info ei_aggr;
+
+				memset(&ei_aggr, 0, sizeof(ei_aggr));
+				ei_aggr.p = aggr->p;
+				ei_aggr.tag = aggr->tag;
+				ei_aggr.instance = ospf->instance;
+				ei_aggr.route_map_set.metric = -1;
+				ei_aggr.route_map_set.metric_type = -1;
+
+				ospf_external_lsa_refresh(ospf, lsa, &ei_aggr,
+						  LSA_REFRESH_FORCE, true);
+				SET_FLAG(aggr->flags,
+					 OSPF_EXTERNAL_AGGRT_ORIGINATED);
+			} else
+				ospf_lsa_flush_as(ospf, lsa);
+		}
+		break;
+	case OSPF_OPAQUE_LINK_LSA:
+	case OSPF_OPAQUE_AREA_LSA:
+	case OSPF_OPAQUE_AS_LSA:
+		new = ospf_opaque_lsa_refresh(lsa);
+		break;
+	default:
+		break;
+	}
+	return new;
+}
+
+void ospf_refresher_register_lsa(struct ospf *ospf, struct ospf_lsa *lsa)
+{
+	uint16_t index, current_index;
+
+	assert(lsa->lock > 0);
+	assert(IS_LSA_SELF(lsa));
+
+	if (lsa->refresh_list < 0) {
+		int delay;
+		int min_delay =
+			ospf->lsa_refresh_timer - (2 * OSPF_LS_REFRESH_JITTER);
+		int max_delay =
+			ospf->lsa_refresh_timer - OSPF_LS_REFRESH_JITTER;
+
+		/* We want to refresh the LSA within OSPF_LS_REFRESH_TIME which
+		 * is
+		 * 1800s. Use jitter so that we send the LSA sometime between
+		 * 1680s
+		 * and 1740s.
+		 */
+		delay = (frr_weak_random() % (max_delay - min_delay))
+			+ min_delay;
+
+		current_index = ospf->lsa_refresh_queue.index
+				+ (monotime(NULL) - ospf->lsa_refresher_started)
+					  / OSPF_LSA_REFRESHER_GRANULARITY;
+
+		index = (current_index + delay / OSPF_LSA_REFRESHER_GRANULARITY)
+			% (OSPF_LSA_REFRESHER_SLOTS);
+
+		if (IS_DEBUG_OSPF(lsa, LSA_REFRESH))
+			zlog_debug(
+				"LSA[Refresh:Type%d:%pI4]: age %d, added to index %d",
+				lsa->data->type, &lsa->data->id,
+				LS_AGE(lsa), index);
+
+		if (!ospf->lsa_refresh_queue.qs[index])
+			ospf->lsa_refresh_queue.qs[index] = list_new();
+
+		listnode_add(ospf->lsa_refresh_queue.qs[index],
+			     ospf_lsa_lock(lsa)); /* lsa_refresh_queue */
+		lsa->refresh_list = index;
+
+		if (IS_DEBUG_OSPF(lsa, LSA_REFRESH))
+			zlog_debug(
+				"LSA[Refresh:Type%d:%pI4]: %s: setting refresh_list on lsa %p (slot %d)",
+				lsa->data->type, &lsa->data->id, __func__,
+				(void *)lsa, index);
+	}
+}
+
+void ospf_refresher_unregister_lsa(struct ospf *ospf, struct ospf_lsa *lsa)
+{
+	assert(lsa->lock > 0);
+	assert(IS_LSA_SELF(lsa));
+	if (lsa->refresh_list >= 0) {
+		struct list *refresh_list =
+			ospf->lsa_refresh_queue.qs[lsa->refresh_list];
+		listnode_delete(refresh_list, lsa);
+		if (!listcount(refresh_list)) {
+			list_delete(&refresh_list);
+			ospf->lsa_refresh_queue.qs[lsa->refresh_list] = NULL;
+		}
+		lsa->refresh_list = -1;
+		ospf_lsa_unlock(&lsa); /* lsa_refresh_queue */
+	}
+}
+
+void ospf_lsa_refresh_walker(struct event *t)
+{
+	struct list *refresh_list;
+	struct listnode *node, *nnode;
+	struct ospf *ospf = EVENT_ARG(t);
+	struct ospf_lsa *lsa;
+	int i;
+	struct list *lsa_to_refresh = list_new();
+	bool dna_lsa;
+
+	if (IS_DEBUG_OSPF(lsa, LSA_REFRESH))
+		zlog_debug("LSA[Refresh]: %s: start", __func__);
+
+
+	i = ospf->lsa_refresh_queue.index;
+
+	/* Note: if clock has jumped backwards, then time change could be
+	   negative,
+	   so we are careful to cast the expression to unsigned before taking
+	   modulus. */
+	ospf->lsa_refresh_queue.index =
+		((unsigned long)(ospf->lsa_refresh_queue.index
+				 + (monotime(NULL)
+				    - ospf->lsa_refresher_started)
+					   / OSPF_LSA_REFRESHER_GRANULARITY))
+		% OSPF_LSA_REFRESHER_SLOTS;
+
+	if (IS_DEBUG_OSPF(lsa, LSA_REFRESH))
+		zlog_debug("LSA[Refresh]: %s: next index %d", __func__,
+			   ospf->lsa_refresh_queue.index);
+
+	for (; i != ospf->lsa_refresh_queue.index;
+	     i = (i + 1) % OSPF_LSA_REFRESHER_SLOTS) {
+		if (IS_DEBUG_OSPF(lsa, LSA_REFRESH))
+			zlog_debug("LSA[Refresh]: %s: refresh index %d",
+				   __func__, i);
+
+		refresh_list = ospf->lsa_refresh_queue.qs[i];
+
+		assert(i >= 0);
+
+		ospf->lsa_refresh_queue.qs[i] = NULL;
+
+		if (refresh_list) {
+			for (ALL_LIST_ELEMENTS(refresh_list, node, nnode,
+					       lsa)) {
+				if (IS_DEBUG_OSPF(lsa, LSA_REFRESH))
+					zlog_debug(
+						"LSA[Refresh:Type%d:%pI4]: %s: refresh lsa %p (slot %d)",
+						lsa->data->type, &lsa->data->id,
+						__func__, (void *)lsa, i);
+
+				assert(lsa->lock > 0);
+				list_delete_node(refresh_list, node);
+				lsa->refresh_list = -1;
+				listnode_add(lsa_to_refresh, lsa);
+			}
+			list_delete(&refresh_list);
+		}
+	}
+
+	ospf->t_lsa_refresher = NULL;
+	event_add_timer(master, ospf_lsa_refresh_walker, ospf,
+			ospf->lsa_refresh_interval, &ospf->t_lsa_refresher);
+	ospf->lsa_refresher_started = monotime(NULL);
+
+	for (ALL_LIST_ELEMENTS(lsa_to_refresh, node, nnode, lsa)) {
+		dna_lsa = ospf_check_dna_lsa(lsa);
+		if (!dna_lsa) { /* refresh only non-DNA LSAs */
+			ospf_lsa_refresh(ospf, lsa);
+		}
+		assert(lsa->lock > 0);
+		ospf_lsa_unlock(&lsa); /* lsa_refresh_queue & temp for
+					* lsa_to_refresh.
+					*/
+	}
+
+	list_delete(&lsa_to_refresh);
+
+	if (IS_DEBUG_OSPF(lsa, LSA_REFRESH))
+		zlog_debug("LSA[Refresh]: %s: end", __func__);
+}
+
+/* Flush the LSAs for the specific area */
+void ospf_flush_lsa_from_area(struct ospf *ospf, struct in_addr area_id,
+			      int type)
+{
+	struct ospf_area *area;
+	struct route_node *rn;
+	struct ospf_lsa *lsa;
+
+	area = ospf_area_get(ospf, area_id);
+
+	switch (type) {
+	case OSPF_AS_EXTERNAL_LSA:
+		if ((area->external_routing == OSPF_AREA_NSSA) ||
+		    (area->external_routing == OSPF_AREA_STUB)) {
+			LSDB_LOOP (EXTERNAL_LSDB(ospf), rn, lsa)
+				if (IS_LSA_SELF(lsa) &&
+				    !(CHECK_FLAG(lsa->flags,
+						 OSPF_LSA_LOCAL_XLT)))
+					ospf_lsa_flush_area(lsa, area);
+		}
+		break;
+	case OSPF_AS_NSSA_LSA:
+		LSDB_LOOP (NSSA_LSDB(area), rn, lsa)
+			if (IS_LSA_SELF(lsa))
+				ospf_lsa_flush_area(lsa, area);
+		break;
+	default:
+		break;
+	}
+}