Adding upstream version 8.4.4.upstream/8.4.4upstream

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

1 files changed, 1064 insertions, 0 deletions

diff --git a/pimd/pim_nht.c b/pimd/pim_nht.c
new file mode 100644
index 0000000..f9a9aeb
--- /dev/null
+++ b/pimd/pim_nht.c
@@ -0,0 +1,1064 @@
+/*
+ * PIM for Quagga
+ * Copyright (C) 2017 Cumulus Networks, Inc.
+ * Chirag Shah
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; see the file COPYING; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+#include <zebra.h>
+#include "network.h"
+#include "zclient.h"
+#include "stream.h"
+#include "nexthop.h"
+#include "if.h"
+#include "hash.h"
+#include "jhash.h"
+
+#include "lib/printfrr.h"
+
+#include "pimd.h"
+#include "pimd/pim_nht.h"
+#include "pim_instance.h"
+#include "log.h"
+#include "pim_time.h"
+#include "pim_oil.h"
+#include "pim_ifchannel.h"
+#include "pim_mroute.h"
+#include "pim_zebra.h"
+#include "pim_upstream.h"
+#include "pim_join.h"
+#include "pim_jp_agg.h"
+#include "pim_zebra.h"
+#include "pim_zlookup.h"
+#include "pim_rp.h"
+#include "pim_addr.h"
+
+/**
+ * pim_sendmsg_zebra_rnh -- Format and send a nexthop register/Unregister
+ *   command to Zebra.
+ */
+void pim_sendmsg_zebra_rnh(struct pim_instance *pim, struct zclient *zclient,
+			   struct pim_nexthop_cache *pnc, int command)
+{
+	struct prefix p;
+	int ret;
+
+	pim_addr_to_prefix(&p, pnc->rpf.rpf_addr);
+	ret = zclient_send_rnh(zclient, command, &p, SAFI_UNICAST, false, false,
+			       pim->vrf->vrf_id);
+	if (ret == ZCLIENT_SEND_FAILURE)
+		zlog_warn("sendmsg_nexthop: zclient_send_message() failed");
+
+	if (PIM_DEBUG_PIM_NHT)
+		zlog_debug(
+			"%s: NHT %sregistered addr %pFX(%s) with Zebra ret:%d ",
+			__func__,
+			(command == ZEBRA_NEXTHOP_REGISTER) ? " " : "de", &p,
+			pim->vrf->name, ret);
+
+	return;
+}
+
+struct pim_nexthop_cache *pim_nexthop_cache_find(struct pim_instance *pim,
+						 struct pim_rpf *rpf)
+{
+	struct pim_nexthop_cache *pnc = NULL;
+	struct pim_nexthop_cache lookup;
+
+	lookup.rpf.rpf_addr = rpf->rpf_addr;
+	pnc = hash_lookup(pim->rpf_hash, &lookup);
+
+	return pnc;
+}
+
+static struct pim_nexthop_cache *pim_nexthop_cache_add(struct pim_instance *pim,
+						       struct pim_rpf *rpf_addr)
+{
+	struct pim_nexthop_cache *pnc;
+	char hash_name[64];
+
+	pnc = XCALLOC(MTYPE_PIM_NEXTHOP_CACHE,
+		      sizeof(struct pim_nexthop_cache));
+	pnc->rpf.rpf_addr = rpf_addr->rpf_addr;
+
+	pnc = hash_get(pim->rpf_hash, pnc, hash_alloc_intern);
+
+	pnc->rp_list = list_new();
+	pnc->rp_list->cmp = pim_rp_list_cmp;
+
+	snprintfrr(hash_name, sizeof(hash_name), "PNC %pPA(%s) Upstream Hash",
+		   &pnc->rpf.rpf_addr, pim->vrf->name);
+	pnc->upstream_hash = hash_create_size(8192, pim_upstream_hash_key,
+					      pim_upstream_equal, hash_name);
+
+	return pnc;
+}
+
+static struct pim_nexthop_cache *pim_nht_get(struct pim_instance *pim,
+					     pim_addr addr)
+{
+	struct pim_nexthop_cache *pnc = NULL;
+	struct pim_rpf rpf;
+	struct zclient *zclient = NULL;
+
+	zclient = pim_zebra_zclient_get();
+	memset(&rpf, 0, sizeof(rpf));
+	rpf.rpf_addr = addr;
+
+	pnc = pim_nexthop_cache_find(pim, &rpf);
+	if (!pnc) {
+		pnc = pim_nexthop_cache_add(pim, &rpf);
+		pim_sendmsg_zebra_rnh(pim, zclient, pnc,
+				      ZEBRA_NEXTHOP_REGISTER);
+		if (PIM_DEBUG_PIM_NHT_DETAIL)
+			zlog_debug(
+				"%s: NHT cache and zebra notification added for %pPA(%s)",
+				__func__, &addr, pim->vrf->name);
+	}
+
+	return pnc;
+}
+
+/* TBD: this does several distinct things and should probably be split up.
+ * (checking state vs. returning pnc vs. adding upstream vs. adding rp)
+ */
+int pim_find_or_track_nexthop(struct pim_instance *pim, pim_addr addr,
+			      struct pim_upstream *up, struct rp_info *rp,
+			      struct pim_nexthop_cache *out_pnc)
+{
+	struct pim_nexthop_cache *pnc;
+	struct listnode *ch_node = NULL;
+
+	pnc = pim_nht_get(pim, addr);
+
+	assertf(up || rp, "addr=%pPA", &addr);
+
+	if (rp != NULL) {
+		ch_node = listnode_lookup(pnc->rp_list, rp);
+		if (ch_node == NULL)
+			listnode_add_sort(pnc->rp_list, rp);
+	}
+
+	if (up != NULL)
+		(void)hash_get(pnc->upstream_hash, up, hash_alloc_intern);
+
+	if (CHECK_FLAG(pnc->flags, PIM_NEXTHOP_VALID)) {
+		if (out_pnc)
+			memcpy(out_pnc, pnc, sizeof(struct pim_nexthop_cache));
+		return 1;
+	}
+
+	return 0;
+}
+
+void pim_nht_bsr_add(struct pim_instance *pim, pim_addr addr)
+{
+	struct pim_nexthop_cache *pnc;
+
+	pnc = pim_nht_get(pim, addr);
+
+	pnc->bsr_count++;
+}
+
+static void pim_nht_drop_maybe(struct pim_instance *pim,
+			       struct pim_nexthop_cache *pnc)
+{
+	if (PIM_DEBUG_PIM_NHT)
+		zlog_debug(
+			"%s: NHT %pPA(%s) rp_list count:%d upstream count:%ld BSR count:%u",
+			__func__, &pnc->rpf.rpf_addr, pim->vrf->name,
+			pnc->rp_list->count, pnc->upstream_hash->count,
+			pnc->bsr_count);
+
+	if (pnc->rp_list->count == 0 && pnc->upstream_hash->count == 0
+	    && pnc->bsr_count == 0) {
+		struct zclient *zclient = pim_zebra_zclient_get();
+
+		pim_sendmsg_zebra_rnh(pim, zclient, pnc,
+				      ZEBRA_NEXTHOP_UNREGISTER);
+
+		list_delete(&pnc->rp_list);
+		hash_free(pnc->upstream_hash);
+
+		hash_release(pim->rpf_hash, pnc);
+		if (pnc->nexthop)
+			nexthops_free(pnc->nexthop);
+		XFREE(MTYPE_PIM_NEXTHOP_CACHE, pnc);
+	}
+}
+
+void pim_delete_tracked_nexthop(struct pim_instance *pim, pim_addr addr,
+				struct pim_upstream *up, struct rp_info *rp)
+{
+	struct pim_nexthop_cache *pnc = NULL;
+	struct pim_nexthop_cache lookup;
+	struct pim_upstream *upstream = NULL;
+
+	/* Remove from RPF hash if it is the last entry */
+	lookup.rpf.rpf_addr = addr;
+	pnc = hash_lookup(pim->rpf_hash, &lookup);
+	if (!pnc) {
+		zlog_warn("attempting to delete nonexistent NHT entry %pPA",
+			  &addr);
+		return;
+	}
+
+	if (rp) {
+		/* Release the (*, G)upstream from pnc->upstream_hash,
+		 * whose Group belongs to the RP getting deleted
+		 */
+		frr_each (rb_pim_upstream, &pim->upstream_head, upstream) {
+			struct prefix grp;
+			struct rp_info *trp_info;
+
+			if (!pim_addr_is_any(upstream->sg.src))
+				continue;
+
+			pim_addr_to_prefix(&grp, upstream->sg.grp);
+			trp_info = pim_rp_find_match_group(pim, &grp);
+			if (trp_info == rp)
+				hash_release(pnc->upstream_hash, upstream);
+		}
+		listnode_delete(pnc->rp_list, rp);
+	}
+
+	if (up)
+		hash_release(pnc->upstream_hash, up);
+
+	pim_nht_drop_maybe(pim, pnc);
+}
+
+void pim_nht_bsr_del(struct pim_instance *pim, pim_addr addr)
+{
+	struct pim_nexthop_cache *pnc = NULL;
+	struct pim_nexthop_cache lookup;
+
+	/*
+	 * Nothing to do here if the address to unregister
+	 * is 0.0.0.0 as that the BSR has not been registered
+	 * for tracking yet.
+	 */
+	if (pim_addr_is_any(addr))
+		return;
+
+	lookup.rpf.rpf_addr = addr;
+
+	pnc = hash_lookup(pim->rpf_hash, &lookup);
+
+	if (!pnc) {
+		zlog_warn("attempting to delete nonexistent NHT BSR entry %pPA",
+			  &addr);
+		return;
+	}
+
+	assertf(pnc->bsr_count > 0, "addr=%pPA", &addr);
+	pnc->bsr_count--;
+
+	pim_nht_drop_maybe(pim, pnc);
+}
+
+bool pim_nht_bsr_rpf_check(struct pim_instance *pim, pim_addr bsr_addr,
+			   struct interface *src_ifp, pim_addr src_ip)
+{
+	struct pim_nexthop_cache *pnc = NULL;
+	struct pim_nexthop_cache lookup;
+	struct pim_neighbor *nbr = NULL;
+	struct nexthop *nh;
+	struct interface *ifp;
+
+	lookup.rpf.rpf_addr = bsr_addr;
+
+	pnc = hash_lookup(pim->rpf_hash, &lookup);
+	if (!pnc || !CHECK_FLAG(pnc->flags, PIM_NEXTHOP_ANSWER_RECEIVED)) {
+		/* BSM from a new freshly registered BSR - do a synchronous
+		 * zebra query since otherwise we'd drop the first packet,
+		 * leading to additional delay in picking up BSM data
+		 */
+
+		/* FIXME: this should really be moved into a generic NHT
+		 * function that does "add and get immediate result" or maybe
+		 * "check cache or get immediate result." But until that can
+		 * be worked in, here's a copy of the code below :(
+		 */
+		struct pim_zlookup_nexthop nexthop_tab[router->multipath];
+		ifindex_t i;
+		struct interface *ifp = NULL;
+		int num_ifindex;
+
+		memset(nexthop_tab, 0, sizeof(nexthop_tab));
+		num_ifindex = zclient_lookup_nexthop(
+			pim, nexthop_tab, router->multipath, bsr_addr,
+			PIM_NEXTHOP_LOOKUP_MAX);
+
+		if (num_ifindex <= 0)
+			return false;
+
+		for (i = 0; i < num_ifindex; i++) {
+			struct pim_zlookup_nexthop *znh = &nexthop_tab[i];
+
+			/* pim_zlookup_nexthop has no ->type */
+
+			/* 1:1 match code below with znh instead of nh */
+			ifp = if_lookup_by_index(znh->ifindex,
+						 pim->vrf->vrf_id);
+
+			if (!ifp || !ifp->info)
+				continue;
+
+			if (if_is_loopback(ifp) && if_is_loopback(src_ifp))
+				return true;
+
+			nbr = pim_neighbor_find(ifp, znh->nexthop_addr);
+			if (!nbr)
+				continue;
+
+			return znh->ifindex == src_ifp->ifindex &&
+			       (!pim_addr_cmp(znh->nexthop_addr, src_ip));
+		}
+		return false;
+	}
+
+	if (!CHECK_FLAG(pnc->flags, PIM_NEXTHOP_VALID))
+		return false;
+
+	/* if we accept BSMs from more than one ECMP nexthop, this will cause
+	 * BSM message "multiplication" for each ECMP hop.  i.e. if you have
+	 * 4-way ECMP and 4 hops you end up with 256 copies of each BSM
+	 * message.
+	 *
+	 * so...  only accept the first (IPv4) valid nexthop as source.
+	 */
+
+	for (nh = pnc->nexthop; nh; nh = nh->next) {
+		pim_addr nhaddr;
+
+		switch (nh->type) {
+#if PIM_IPV == 4
+		case NEXTHOP_TYPE_IPV4:
+			if (nh->ifindex == IFINDEX_INTERNAL)
+				continue;
+
+			/* fallthru */
+		case NEXTHOP_TYPE_IPV4_IFINDEX:
+			nhaddr = nh->gate.ipv4;
+			break;
+#else
+		case NEXTHOP_TYPE_IPV6:
+			if (nh->ifindex == IFINDEX_INTERNAL)
+				continue;
+
+			/* fallthru */
+		case NEXTHOP_TYPE_IPV6_IFINDEX:
+			nhaddr = nh->gate.ipv6;
+			break;
+#endif
+		case NEXTHOP_TYPE_IFINDEX:
+			nhaddr = bsr_addr;
+			break;
+
+		default:
+			continue;
+		}
+
+		ifp = if_lookup_by_index(nh->ifindex, pim->vrf->vrf_id);
+		if (!ifp || !ifp->info)
+			continue;
+
+		if (if_is_loopback(ifp) && if_is_loopback(src_ifp))
+			return true;
+
+		/* MRIB (IGP) may be pointing at a router where PIM is down */
+		nbr = pim_neighbor_find(ifp, nhaddr);
+		if (!nbr)
+			continue;
+
+		return nh->ifindex == src_ifp->ifindex &&
+		       (!pim_addr_cmp(nhaddr, src_ip));
+	}
+	return false;
+}
+
+void pim_rp_nexthop_del(struct rp_info *rp_info)
+{
+	rp_info->rp.source_nexthop.interface = NULL;
+	rp_info->rp.source_nexthop.mrib_nexthop_addr = PIMADDR_ANY;
+	rp_info->rp.source_nexthop.mrib_metric_preference =
+		router->infinite_assert_metric.metric_preference;
+	rp_info->rp.source_nexthop.mrib_route_metric =
+		router->infinite_assert_metric.route_metric;
+}
+
+/* Update RP nexthop info based on Nexthop update received from Zebra.*/
+static void pim_update_rp_nh(struct pim_instance *pim,
+			     struct pim_nexthop_cache *pnc)
+{
+	struct listnode *node = NULL;
+	struct rp_info *rp_info = NULL;
+
+	/*Traverse RP list and update each RP Nexthop info */
+	for (ALL_LIST_ELEMENTS_RO(pnc->rp_list, node, rp_info)) {
+		if (pim_rpf_addr_is_inaddr_any(&rp_info->rp))
+			continue;
+
+		// Compute PIM RPF using cached nexthop
+		if (!pim_ecmp_nexthop_lookup(pim, &rp_info->rp.source_nexthop,
+					     rp_info->rp.rpf_addr,
+					     &rp_info->group, 1))
+			pim_rp_nexthop_del(rp_info);
+	}
+}
+
+/* Update Upstream nexthop info based on Nexthop update received from Zebra.*/
+static int pim_update_upstream_nh_helper(struct hash_bucket *bucket, void *arg)
+{
+	struct pim_instance *pim = (struct pim_instance *)arg;
+	struct pim_upstream *up = (struct pim_upstream *)bucket->data;
+
+	enum pim_rpf_result rpf_result;
+	struct pim_rpf old;
+
+	old.source_nexthop.interface = up->rpf.source_nexthop.interface;
+	rpf_result = pim_rpf_update(pim, up, &old, __func__);
+
+	/* update kernel multicast forwarding cache (MFC); if the
+	 * RPF nbr is now unreachable the MFC has already been updated
+	 * by pim_rpf_clear
+	 */
+	if (rpf_result == PIM_RPF_CHANGED)
+		pim_upstream_mroute_iif_update(up->channel_oil, __func__);
+
+	if (rpf_result == PIM_RPF_CHANGED ||
+		(rpf_result == PIM_RPF_FAILURE && old.source_nexthop.interface))
+		pim_zebra_upstream_rpf_changed(pim, up, &old);
+
+
+	if (PIM_DEBUG_PIM_NHT) {
+		zlog_debug(
+			"%s: NHT upstream %s(%s) old ifp %s new ifp %s",
+			__func__, up->sg_str, pim->vrf->name,
+			old.source_nexthop.interface ? old.source_nexthop
+							       .interface->name
+						     : "Unknown",
+			up->rpf.source_nexthop.interface ? up->rpf.source_nexthop
+								   .interface->name
+							 : "Unknown");
+	}
+
+	return HASHWALK_CONTINUE;
+}
+
+static int pim_update_upstream_nh(struct pim_instance *pim,
+				  struct pim_nexthop_cache *pnc)
+{
+	hash_walk(pnc->upstream_hash, pim_update_upstream_nh_helper, pim);
+
+	pim_zebra_update_all_interfaces(pim);
+
+	return 0;
+}
+
+uint32_t pim_compute_ecmp_hash(struct prefix *src, struct prefix *grp)
+{
+	uint32_t hash_val;
+
+	if (!src)
+		return 0;
+
+	hash_val = prefix_hash_key(src);
+	if (grp)
+		hash_val ^= prefix_hash_key(grp);
+	return hash_val;
+}
+
+static int pim_ecmp_nexthop_search(struct pim_instance *pim,
+				   struct pim_nexthop_cache *pnc,
+				   struct pim_nexthop *nexthop, pim_addr src,
+				   struct prefix *grp, int neighbor_needed)
+{
+	struct pim_neighbor *nbrs[router->multipath], *nbr = NULL;
+	struct interface *ifps[router->multipath];
+	struct nexthop *nh_node = NULL;
+	ifindex_t first_ifindex;
+	struct interface *ifp = NULL;
+	uint32_t hash_val = 0, mod_val = 0;
+	uint8_t nh_iter = 0, found = 0;
+	uint32_t i, num_nbrs = 0;
+
+	if (!pnc || !pnc->nexthop_num || !nexthop)
+		return 0;
+
+	pim_addr nh_addr = nexthop->mrib_nexthop_addr;
+	pim_addr grp_addr = pim_addr_from_prefix(grp);
+
+	memset(&nbrs, 0, sizeof(nbrs));
+	memset(&ifps, 0, sizeof(ifps));
+
+
+	// Current Nexthop is VALID, check to stay on the current path.
+	if (nexthop->interface && nexthop->interface->info &&
+	    (!pim_addr_is_any(nh_addr))) {
+		/* User configured knob to explicitly switch
+		   to new path is disabled or current path
+		   metric is less than nexthop update.
+		 */
+
+		if (pim->ecmp_rebalance_enable == 0) {
+			uint8_t curr_route_valid = 0;
+			// Check if current nexthop is present in new updated
+			// Nexthop list.
+			// If the current nexthop is not valid, candidate to
+			// choose new Nexthop.
+			for (nh_node = pnc->nexthop; nh_node;
+			     nh_node = nh_node->next) {
+				curr_route_valid = (nexthop->interface->ifindex
+						    == nh_node->ifindex);
+				if (curr_route_valid)
+					break;
+			}
+
+			if (curr_route_valid &&
+			    !pim_if_connected_to_source(nexthop->interface,
+							src)) {
+				nbr = pim_neighbor_find(
+					nexthop->interface,
+					nexthop->mrib_nexthop_addr);
+				if (!nbr
+				    && !if_is_loopback(nexthop->interface)) {
+					if (PIM_DEBUG_PIM_NHT)
+						zlog_debug(
+							"%s: current nexthop does not have nbr ",
+							__func__);
+				} else {
+					/* update metric even if the upstream
+					 * neighbor stays unchanged
+					 */
+					nexthop->mrib_metric_preference =
+						pnc->distance;
+					nexthop->mrib_route_metric =
+						pnc->metric;
+					if (PIM_DEBUG_PIM_NHT)
+						zlog_debug(
+							"%s: (%pPA,%pPA)(%s) current nexthop %s is valid, skipping new path selection",
+							__func__, &src,
+							&grp_addr,
+							pim->vrf->name,
+							nexthop->interface->name);
+					return 1;
+				}
+			}
+		}
+	}
+
+	/*
+	 * Look up all interfaces and neighbors,
+	 * store for later usage
+	 */
+	for (nh_node = pnc->nexthop, i = 0; nh_node;
+	     nh_node = nh_node->next, i++) {
+		ifps[i] =
+			if_lookup_by_index(nh_node->ifindex, pim->vrf->vrf_id);
+		if (ifps[i]) {
+#if PIM_IPV == 4
+			pim_addr nhaddr = nh_node->gate.ipv4;
+#else
+			pim_addr nhaddr = nh_node->gate.ipv6;
+#endif
+			nbrs[i] = pim_neighbor_find(ifps[i], nhaddr);
+			if (nbrs[i] || pim_if_connected_to_source(ifps[i], src))
+				num_nbrs++;
+		}
+	}
+	if (pim->ecmp_enable) {
+		struct prefix src_pfx;
+		uint32_t consider = pnc->nexthop_num;
+
+		if (neighbor_needed && num_nbrs < consider)
+			consider = num_nbrs;
+
+		if (consider == 0)
+			return 0;
+
+		// PIM ECMP flag is enable then choose ECMP path.
+		pim_addr_to_prefix(&src_pfx, src);
+		hash_val = pim_compute_ecmp_hash(&src_pfx, grp);
+		mod_val = hash_val % consider;
+	}
+
+	for (nh_node = pnc->nexthop; nh_node && (found == 0);
+	     nh_node = nh_node->next) {
+		first_ifindex = nh_node->ifindex;
+		ifp = ifps[nh_iter];
+		if (!ifp) {
+			if (PIM_DEBUG_PIM_NHT)
+				zlog_debug(
+					"%s %s: could not find interface for ifindex %d (address %pPA(%s))",
+					__FILE__, __func__, first_ifindex, &src,
+					pim->vrf->name);
+			if (nh_iter == mod_val)
+				mod_val++; // Select nexthpath
+			nh_iter++;
+			continue;
+		}
+		if (!ifp->info) {
+			if (PIM_DEBUG_PIM_NHT)
+				zlog_debug(
+					"%s: multicast not enabled on input interface %s(%s) (ifindex=%d, RPF for source %pPA)",
+					__func__, ifp->name, pim->vrf->name,
+					first_ifindex, &src);
+			if (nh_iter == mod_val)
+				mod_val++; // Select nexthpath
+			nh_iter++;
+			continue;
+		}
+
+		if (neighbor_needed && !pim_if_connected_to_source(ifp, src)) {
+			nbr = nbrs[nh_iter];
+			if (!nbr && !if_is_loopback(ifp)) {
+				if (PIM_DEBUG_PIM_NHT)
+					zlog_debug(
+						"%s: pim nbr not found on input interface %s(%s)",
+						__func__, ifp->name,
+						pim->vrf->name);
+				if (nh_iter == mod_val)
+					mod_val++; // Select nexthpath
+				nh_iter++;
+				continue;
+			}
+		}
+
+		if (nh_iter == mod_val) {
+			nexthop->interface = ifp;
+#if PIM_IPV == 4
+			nexthop->mrib_nexthop_addr = nh_node->gate.ipv4;
+#else
+			nexthop->mrib_nexthop_addr = nh_node->gate.ipv6;
+#endif
+			nexthop->mrib_metric_preference = pnc->distance;
+			nexthop->mrib_route_metric = pnc->metric;
+			nexthop->last_lookup = src;
+			nexthop->last_lookup_time = pim_time_monotonic_usec();
+			nexthop->nbr = nbr;
+			found = 1;
+			if (PIM_DEBUG_PIM_NHT)
+				zlog_debug(
+					"%s: (%pPA,%pPA)(%s) selected nhop interface %s addr %pPAs mod_val %u iter %d ecmp %d",
+					__func__, &src, &grp_addr,
+					pim->vrf->name, ifp->name, &nh_addr,
+					mod_val, nh_iter, pim->ecmp_enable);
+		}
+		nh_iter++;
+	}
+
+	if (found)
+		return 1;
+	else
+		return 0;
+}
+
+/* This API is used to parse Registered address nexthop update coming from Zebra
+ */
+int pim_parse_nexthop_update(ZAPI_CALLBACK_ARGS)
+{
+	struct nexthop *nexthop;
+	struct nexthop *nhlist_head = NULL;
+	struct nexthop *nhlist_tail = NULL;
+	int i;
+	struct pim_rpf rpf;
+	struct pim_nexthop_cache *pnc = NULL;
+	struct interface *ifp = NULL;
+	struct vrf *vrf = vrf_lookup_by_id(vrf_id);
+	struct pim_instance *pim;
+	struct zapi_route nhr;
+	struct prefix match;
+
+	if (!vrf)
+		return 0;
+	pim = vrf->info;
+
+	if (!zapi_nexthop_update_decode(zclient->ibuf, &match, &nhr)) {
+		zlog_err("%s: Decode of nexthop update from zebra failed",
+			 __func__);
+		return 0;
+	}
+
+	if (cmd == ZEBRA_NEXTHOP_UPDATE) {
+		rpf.rpf_addr = pim_addr_from_prefix(&match);
+		pnc = pim_nexthop_cache_find(pim, &rpf);
+		if (!pnc) {
+			if (PIM_DEBUG_PIM_NHT)
+				zlog_debug(
+					"%s: Skipping NHT update, addr %pPA is not in local cached DB.",
+					__func__, &rpf.rpf_addr);
+			return 0;
+		}
+	} else {
+		/*
+		 * We do not currently handle ZEBRA_IMPORT_CHECK_UPDATE
+		 */
+		return 0;
+	}
+
+	pnc->last_update = pim_time_monotonic_usec();
+
+	if (nhr.nexthop_num) {
+		pnc->nexthop_num = 0; // Only increment for pim enabled rpf.
+
+		for (i = 0; i < nhr.nexthop_num; i++) {
+			nexthop = nexthop_from_zapi_nexthop(&nhr.nexthops[i]);
+			switch (nexthop->type) {
+			case NEXTHOP_TYPE_IFINDEX:
+				/*
+				 * Connected route (i.e. no nexthop), use
+				 * RPF address from nexthop cache (i.e.
+				 * destination) as PIM nexthop.
+				 */
+#if PIM_IPV == 4
+				nexthop->type = NEXTHOP_TYPE_IPV4_IFINDEX;
+				nexthop->gate.ipv4 = pnc->rpf.rpf_addr;
+#else
+				nexthop->type = NEXTHOP_TYPE_IPV6_IFINDEX;
+				nexthop->gate.ipv6 = pnc->rpf.rpf_addr;
+#endif
+				break;
+#if PIM_IPV == 4
+			/* RFC5549 IPv4-over-IPv6 nexthop handling:
+			 * if we get an IPv6 nexthop in IPv4 PIM, hunt down a
+			 * PIM neighbor and use that instead.
+			 */
+			case NEXTHOP_TYPE_IPV6_IFINDEX: {
+				struct interface *ifp1 = NULL;
+				struct pim_neighbor *nbr = NULL;
+
+				ifp1 = if_lookup_by_index(nexthop->ifindex,
+							  pim->vrf->vrf_id);
+
+				if (!ifp1)
+					nbr = NULL;
+				else
+					/* FIXME: should really use nbr's
+					 * secondary address list here
+					 */
+					nbr = pim_neighbor_find_if(ifp1);
+
+				/* Overwrite with Nbr address as NH addr */
+				if (nbr)
+					nexthop->gate.ipv4 = nbr->source_addr;
+				else
+					// Mark nexthop address to 0 until PIM
+					// Nbr is resolved.
+					nexthop->gate.ipv4 = PIMADDR_ANY;
+
+				break;
+			}
+#else
+			case NEXTHOP_TYPE_IPV6_IFINDEX:
+#endif
+			case NEXTHOP_TYPE_IPV6:
+			case NEXTHOP_TYPE_IPV4:
+			case NEXTHOP_TYPE_IPV4_IFINDEX:
+			case NEXTHOP_TYPE_BLACKHOLE:
+				/* nothing to do for the other nexthop types */
+				break;
+			}
+
+			ifp = if_lookup_by_index(nexthop->ifindex,
+						 pim->vrf->vrf_id);
+			if (!ifp) {
+				if (PIM_DEBUG_PIM_NHT) {
+					char buf[NEXTHOP_STRLEN];
+					zlog_debug(
+						"%s: could not find interface for ifindex %d(%s) (addr %s)",
+						__func__, nexthop->ifindex,
+						pim->vrf->name,
+						nexthop2str(nexthop, buf,
+							    sizeof(buf)));
+				}
+				nexthop_free(nexthop);
+				continue;
+			}
+
+			if (PIM_DEBUG_PIM_NHT) {
+#if PIM_IPV == 4
+				pim_addr nhaddr = nexthop->gate.ipv4;
+#else
+				pim_addr nhaddr = nexthop->gate.ipv6;
+#endif
+				zlog_debug(
+					"%s: NHT addr %pFX(%s) %d-nhop via %pPA(%s) type %d distance:%u metric:%u ",
+					__func__, &match, pim->vrf->name, i + 1,
+					&nhaddr, ifp->name, nexthop->type,
+					nhr.distance, nhr.metric);
+			}
+
+			if (!ifp->info) {
+				/*
+				 * Though Multicast is not enabled on this
+				 * Interface store it in database otheriwse we
+				 * may miss this update and this will not cause
+				 * any issue, because while choosing the path we
+				 * are ommitting the Interfaces which are not
+				 * multicast enabled
+				 */
+				if (PIM_DEBUG_PIM_NHT) {
+					char buf[NEXTHOP_STRLEN];
+
+					zlog_debug(
+						"%s: multicast not enabled on input interface %s(%s) (ifindex=%d, addr %s)",
+						__func__, ifp->name,
+						pim->vrf->name,
+						nexthop->ifindex,
+						nexthop2str(nexthop, buf,
+							    sizeof(buf)));
+				}
+			}
+
+			if (nhlist_tail) {
+				nhlist_tail->next = nexthop;
+				nhlist_tail = nexthop;
+			} else {
+				nhlist_tail = nexthop;
+				nhlist_head = nexthop;
+			}
+			// Only keep track of nexthops which are PIM enabled.
+			pnc->nexthop_num++;
+		}
+		/* Reset existing pnc->nexthop before assigning new list */
+		nexthops_free(pnc->nexthop);
+		pnc->nexthop = nhlist_head;
+		if (pnc->nexthop_num) {
+			pnc->flags |= PIM_NEXTHOP_VALID;
+			pnc->distance = nhr.distance;
+			pnc->metric = nhr.metric;
+		}
+	} else {
+		pnc->flags &= ~PIM_NEXTHOP_VALID;
+		pnc->nexthop_num = nhr.nexthop_num;
+		nexthops_free(pnc->nexthop);
+		pnc->nexthop = NULL;
+	}
+	SET_FLAG(pnc->flags, PIM_NEXTHOP_ANSWER_RECEIVED);
+
+	if (PIM_DEBUG_PIM_NHT)
+		zlog_debug(
+			"%s: NHT Update for %pFX(%s) num_nh %d num_pim_nh %d vrf:%u up %ld rp %d",
+			__func__, &match, pim->vrf->name, nhr.nexthop_num,
+			pnc->nexthop_num, vrf_id, pnc->upstream_hash->count,
+			listcount(pnc->rp_list));
+
+	pim_rpf_set_refresh_time(pim);
+
+	if (listcount(pnc->rp_list))
+		pim_update_rp_nh(pim, pnc);
+	if (pnc->upstream_hash->count)
+		pim_update_upstream_nh(pim, pnc);
+
+	return 0;
+}
+
+int pim_ecmp_nexthop_lookup(struct pim_instance *pim,
+			    struct pim_nexthop *nexthop, pim_addr src,
+			    struct prefix *grp, int neighbor_needed)
+{
+	struct pim_nexthop_cache *pnc;
+	struct pim_zlookup_nexthop nexthop_tab[router->multipath];
+	struct pim_neighbor *nbrs[router->multipath], *nbr = NULL;
+	struct pim_rpf rpf;
+	int num_ifindex;
+	struct interface *ifps[router->multipath], *ifp;
+	int first_ifindex;
+	int found = 0;
+	uint8_t i = 0;
+	uint32_t hash_val = 0, mod_val = 0;
+	uint32_t num_nbrs = 0;
+
+	if (PIM_DEBUG_PIM_NHT_DETAIL)
+		zlog_debug("%s: Looking up: %pPA(%s), last lookup time: %lld",
+			   __func__, &src, pim->vrf->name,
+			   nexthop->last_lookup_time);
+
+	rpf.rpf_addr = src;
+
+	pnc = pim_nexthop_cache_find(pim, &rpf);
+	if (pnc) {
+		if (CHECK_FLAG(pnc->flags, PIM_NEXTHOP_ANSWER_RECEIVED))
+		    return pim_ecmp_nexthop_search(pim, pnc, nexthop, src, grp,
+						   neighbor_needed);
+	}
+
+	memset(nexthop_tab, 0,
+	       sizeof(struct pim_zlookup_nexthop) * router->multipath);
+	num_ifindex =
+		zclient_lookup_nexthop(pim, nexthop_tab, router->multipath, src,
+				       PIM_NEXTHOP_LOOKUP_MAX);
+	if (num_ifindex < 1) {
+		if (PIM_DEBUG_PIM_NHT)
+			zlog_warn(
+				"%s: could not find nexthop ifindex for address %pPA(%s)",
+				__func__, &src, pim->vrf->name);
+		return 0;
+	}
+
+	memset(&nbrs, 0, sizeof(nbrs));
+	memset(&ifps, 0, sizeof(ifps));
+
+	/*
+	 * Look up all interfaces and neighbors,
+	 * store for later usage
+	 */
+	for (i = 0; i < num_ifindex; i++) {
+		ifps[i] = if_lookup_by_index(nexthop_tab[i].ifindex,
+					     pim->vrf->vrf_id);
+		if (ifps[i]) {
+			nbrs[i] = pim_neighbor_find(
+				ifps[i], nexthop_tab[i].nexthop_addr);
+			if (nbrs[i] || pim_if_connected_to_source(ifps[i], src))
+				num_nbrs++;
+		}
+	}
+
+	// If PIM ECMP enable then choose ECMP path.
+	if (pim->ecmp_enable) {
+		struct prefix src_pfx;
+		uint32_t consider = num_ifindex;
+
+		if (neighbor_needed && num_nbrs < consider)
+			consider = num_nbrs;
+
+		if (consider == 0)
+			return 0;
+
+		pim_addr_to_prefix(&src_pfx, src);
+		hash_val = pim_compute_ecmp_hash(&src_pfx, grp);
+		mod_val = hash_val % consider;
+		if (PIM_DEBUG_PIM_NHT_DETAIL)
+			zlog_debug("%s: hash_val %u mod_val %u", __func__,
+				   hash_val, mod_val);
+	}
+
+	i = 0;
+	while (!found && (i < num_ifindex)) {
+		first_ifindex = nexthop_tab[i].ifindex;
+
+		ifp = ifps[i];
+		if (!ifp) {
+			if (PIM_DEBUG_PIM_NHT)
+				zlog_debug(
+					"%s %s: could not find interface for ifindex %d (address %pPA(%s))",
+					__FILE__, __func__, first_ifindex, &src,
+					pim->vrf->name);
+			if (i == mod_val)
+				mod_val++;
+			i++;
+			continue;
+		}
+
+		if (!ifp->info) {
+			if (PIM_DEBUG_PIM_NHT)
+				zlog_debug(
+					"%s: multicast not enabled on input interface %s(%s) (ifindex=%d, RPF for source %pPA)",
+					__func__, ifp->name, pim->vrf->name,
+					first_ifindex, &src);
+			if (i == mod_val)
+				mod_val++;
+			i++;
+			continue;
+		}
+		if (neighbor_needed && !pim_if_connected_to_source(ifp, src)) {
+			nbr = nbrs[i];
+			if (PIM_DEBUG_PIM_NHT_DETAIL)
+				zlog_debug("ifp name: %s(%s), pim nbr: %p",
+					   ifp->name, pim->vrf->name, nbr);
+			if (!nbr && !if_is_loopback(ifp)) {
+				if (i == mod_val)
+					mod_val++;
+				if (PIM_DEBUG_PIM_NHT)
+					zlog_debug(
+						"%s: NBR (%pPA) not found on input interface %s(%s) (RPF for source %pPA)",
+						__func__,
+						&nexthop_tab[i].nexthop_addr,
+						ifp->name, pim->vrf->name,
+						&src);
+				i++;
+				continue;
+			}
+		}
+
+		if (i == mod_val) {
+			if (PIM_DEBUG_PIM_NHT)
+				zlog_debug(
+					"%s: found nhop %pPA for addr %pPA interface %s(%s) metric %d dist %d",
+					__func__, &nexthop_tab[i].nexthop_addr,
+					&src, ifp->name, pim->vrf->name,
+					nexthop_tab[i].route_metric,
+					nexthop_tab[i].protocol_distance);
+			/* update nexthop data */
+			nexthop->interface = ifp;
+			nexthop->mrib_nexthop_addr =
+				nexthop_tab[i].nexthop_addr;
+			nexthop->mrib_metric_preference =
+				nexthop_tab[i].protocol_distance;
+			nexthop->mrib_route_metric =
+				nexthop_tab[i].route_metric;
+			nexthop->last_lookup = src;
+			nexthop->last_lookup_time = pim_time_monotonic_usec();
+			nexthop->nbr = nbr;
+			found = 1;
+		}
+		i++;
+	}
+
+	if (found)
+		return 1;
+	else
+		return 0;
+}
+
+int pim_ecmp_fib_lookup_if_vif_index(struct pim_instance *pim, pim_addr src,
+				     struct prefix *grp)
+{
+	struct pim_nexthop nhop;
+	int vif_index;
+	ifindex_t ifindex;
+
+	memset(&nhop, 0, sizeof(nhop));
+	if (!pim_ecmp_nexthop_lookup(pim, &nhop, src, grp, 1)) {
+		if (PIM_DEBUG_PIM_NHT)
+			zlog_debug(
+				"%s: could not find nexthop ifindex for address %pPA(%s)",
+				__func__, &src, pim->vrf->name);
+		return -1;
+	}
+
+	ifindex = nhop.interface->ifindex;
+	if (PIM_DEBUG_PIM_NHT)
+		zlog_debug(
+			"%s: found nexthop ifindex=%d (interface %s(%s)) for address %pPA",
+			__func__, ifindex,
+			ifindex2ifname(ifindex, pim->vrf->vrf_id),
+			pim->vrf->name, &src);
+
+	vif_index = pim_if_find_vifindex_by_ifindex(pim, ifindex);
+
+	if (vif_index < 0) {
+		if (PIM_DEBUG_PIM_NHT) {
+			zlog_debug(
+				"%s: low vif_index=%d(%s) < 1 nexthop for address %pPA",
+				__func__, vif_index, pim->vrf->name, &src);
+		}
+		return -2;
+	}
+
+	return vif_index;
+}