zebra_rib.c

/* Routing Information Base.
 * Copyright (C) 1997, 98, 99, 2001 Kunihiro Ishiguro
 *
 * This file is part of GNU Zebra.
 *
 * GNU Zebra 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, or (at your option) any
 * later version.
 *
 * GNU Zebra 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 "command.h"
#include "if.h"
#include "linklist.h"
#include "log.h"
#include "log_int.h"
#include "memory.h"
#include "mpls.h"
#include "nexthop.h"
#include "prefix.h"
#include "prefix.h"
#include "routemap.h"
#include "sockunion.h"
#include "srcdest_table.h"
#include "table.h"
#include "thread.h"
#include "vrf.h"
#include "workqueue.h"

#include "zebra/zebra_router.h"
#include "zebra/connected.h"
#include "zebra/debug.h"
#include "zebra/interface.h"
#include "zebra/redistribute.h"
#include "zebra/rib.h"
#include "zebra/rt.h"
#include "zebra/zapi_msg.h"
#include "zebra/zebra_errors.h"
#include "zebra/zebra_memory.h"
#include "zebra/zebra_ns.h"
#include "zebra/zebra_rnh.h"
#include "zebra/zebra_routemap.h"
#include "zebra/zebra_vrf.h"
#include "zebra/zebra_vxlan.h"
#include "zebra/zapi_msg.h"
#include "zebra/zebra_dplane.h"

/*
 * Event, list, and mutex for delivery of dataplane results
 */
static pthread_mutex_t dplane_mutex;
static struct thread *t_dplane;
static struct dplane_ctx_q rib_dplane_q;

DEFINE_HOOK(rib_update, (struct route_node * rn, const char *reason),
	    (rn, reason))

/* Should we allow non Quagga processes to delete our routes */
extern int allow_delete;

/* Each route type's string and default distance value. */
static const struct {
	int key;
	int distance;
} route_info[ZEBRA_ROUTE_MAX] = {
		[ZEBRA_ROUTE_SYSTEM] = {ZEBRA_ROUTE_SYSTEM, 0},
		[ZEBRA_ROUTE_KERNEL] = {ZEBRA_ROUTE_KERNEL, 0},
		[ZEBRA_ROUTE_CONNECT] = {ZEBRA_ROUTE_CONNECT, 0},
		[ZEBRA_ROUTE_STATIC] = {ZEBRA_ROUTE_STATIC, 1},
		[ZEBRA_ROUTE_RIP] = {ZEBRA_ROUTE_RIP, 120},
		[ZEBRA_ROUTE_RIPNG] = {ZEBRA_ROUTE_RIPNG, 120},
		[ZEBRA_ROUTE_OSPF] = {ZEBRA_ROUTE_OSPF, 110},
		[ZEBRA_ROUTE_OSPF6] = {ZEBRA_ROUTE_OSPF6, 110},
		[ZEBRA_ROUTE_ISIS] = {ZEBRA_ROUTE_ISIS, 115},
		[ZEBRA_ROUTE_BGP] = {ZEBRA_ROUTE_BGP, 20 /* IBGP is 200. */},
		[ZEBRA_ROUTE_PIM] = {ZEBRA_ROUTE_PIM, 255},
		[ZEBRA_ROUTE_EIGRP] = {ZEBRA_ROUTE_EIGRP, 90},
		[ZEBRA_ROUTE_NHRP] = {ZEBRA_ROUTE_NHRP, 10},
		[ZEBRA_ROUTE_HSLS] = {ZEBRA_ROUTE_HSLS, 255},
		[ZEBRA_ROUTE_OLSR] = {ZEBRA_ROUTE_OLSR, 255},
		[ZEBRA_ROUTE_TABLE] = {ZEBRA_ROUTE_TABLE, 150},
		[ZEBRA_ROUTE_LDP] = {ZEBRA_ROUTE_LDP, 150},
		[ZEBRA_ROUTE_VNC] = {ZEBRA_ROUTE_VNC, 20},
		[ZEBRA_ROUTE_VNC_DIRECT] = {ZEBRA_ROUTE_VNC_DIRECT, 20},
		[ZEBRA_ROUTE_VNC_DIRECT_RH] = {ZEBRA_ROUTE_VNC_DIRECT_RH, 20},
		[ZEBRA_ROUTE_BGP_DIRECT] = {ZEBRA_ROUTE_BGP_DIRECT, 20},
		[ZEBRA_ROUTE_BGP_DIRECT_EXT] = {ZEBRA_ROUTE_BGP_DIRECT_EXT, 20},
		[ZEBRA_ROUTE_BABEL] = {ZEBRA_ROUTE_BABEL, 100},
		[ZEBRA_ROUTE_SHARP] = {ZEBRA_ROUTE_SHARP, 150},

	/* no entry/default: 150 */
};

/* RPF lookup behaviour */
static enum multicast_mode ipv4_multicast_mode = MCAST_NO_CONFIG;


static void __attribute__((format(printf, 5, 6)))
_rnode_zlog(const char *_func, vrf_id_t vrf_id, struct route_node *rn,
	    int priority, const char *msgfmt, ...)
{
	char buf[SRCDEST2STR_BUFFER + sizeof(" (MRIB)")];
	char msgbuf[512];
	va_list ap;

	va_start(ap, msgfmt);
	vsnprintf(msgbuf, sizeof(msgbuf), msgfmt, ap);
	va_end(ap);

	if (rn) {
		rib_table_info_t *info = srcdest_rnode_table_info(rn);
		srcdest_rnode2str(rn, buf, sizeof(buf));

		if (info->safi == SAFI_MULTICAST)
			strcat(buf, " (MRIB)");
	} else {
		snprintf(buf, sizeof(buf), "{(route_node *) NULL}");
	}

	zlog(priority, "%s: %d:%s: %s", _func, vrf_id, buf, msgbuf);
}

#define rnode_debug(node, vrf_id, ...)                                         \
	_rnode_zlog(__func__, vrf_id, node, LOG_DEBUG, __VA_ARGS__)
#define rnode_info(node, ...)                                                  \
	_rnode_zlog(__func__, vrf_id, node, LOG_INFO, __VA_ARGS__)

uint8_t route_distance(int type)
{
	uint8_t distance;

	if ((unsigned)type >= array_size(route_info))
		distance = 150;
	else
		distance = route_info[type].distance;

	return distance;
}

int is_zebra_valid_kernel_table(uint32_t table_id)
{
#ifdef linux
	if ((table_id == RT_TABLE_UNSPEC) || (table_id == RT_TABLE_LOCAL)
	    || (table_id == RT_TABLE_COMPAT))
		return 0;
#endif

	return 1;
}

int is_zebra_main_routing_table(uint32_t table_id)
{
	if ((table_id == RT_TABLE_MAIN)
	    || (table_id == zebrad.rtm_table_default))
		return 1;
	return 0;
}

int zebra_check_addr(const struct prefix *p)
{
	if (p->family == AF_INET) {
		uint32_t addr;

		addr = p->u.prefix4.s_addr;
		addr = ntohl(addr);

		if (IPV4_NET127(addr) || IN_CLASSD(addr)
		    || IPV4_LINKLOCAL(addr))
			return 0;
	}
	if (p->family == AF_INET6) {
		if (IN6_IS_ADDR_LOOPBACK(&p->u.prefix6))
			return 0;
		if (IN6_IS_ADDR_LINKLOCAL(&p->u.prefix6))
			return 0;
	}
	return 1;
}

/* Add nexthop to the end of a rib node's nexthop list */
void route_entry_nexthop_add(struct route_entry *re, struct nexthop *nexthop)
{
	nexthop_add(&re->ng.nexthop, nexthop);
	re->nexthop_num++;
}


/**
 * copy_nexthop - copy a nexthop to the rib structure.
 */
void route_entry_copy_nexthops(struct route_entry *re, struct nexthop *nh)
{
	assert(!re->ng.nexthop);
	copy_nexthops(&re->ng.nexthop, nh, NULL);
	for (struct nexthop *nexthop = nh; nexthop; nexthop = nexthop->next)
		re->nexthop_num++;
}

/* Delete specified nexthop from the list. */
void route_entry_nexthop_delete(struct route_entry *re, struct nexthop *nexthop)
{
	if (nexthop->next)
		nexthop->next->prev = nexthop->prev;
	if (nexthop->prev)
		nexthop->prev->next = nexthop->next;
	else
		re->ng.nexthop = nexthop->next;
	re->nexthop_num--;
}


struct nexthop *route_entry_nexthop_ifindex_add(struct route_entry *re,
						ifindex_t ifindex,
						vrf_id_t nh_vrf_id)
{
	struct nexthop *nexthop;

	nexthop = nexthop_new();
	nexthop->type = NEXTHOP_TYPE_IFINDEX;
	nexthop->ifindex = ifindex;
	nexthop->vrf_id = nh_vrf_id;

	route_entry_nexthop_add(re, nexthop);

	return nexthop;
}

struct nexthop *route_entry_nexthop_ipv4_add(struct route_entry *re,
					     struct in_addr *ipv4,
					     struct in_addr *src,
					     vrf_id_t nh_vrf_id)
{
	struct nexthop *nexthop;

	nexthop = nexthop_new();
	nexthop->type = NEXTHOP_TYPE_IPV4;
	nexthop->vrf_id = nh_vrf_id;
	nexthop->gate.ipv4 = *ipv4;
	if (src)
		nexthop->src.ipv4 = *src;

	route_entry_nexthop_add(re, nexthop);

	return nexthop;
}

struct nexthop *route_entry_nexthop_ipv4_ifindex_add(struct route_entry *re,
						     struct in_addr *ipv4,
						     struct in_addr *src,
						     ifindex_t ifindex,
						     vrf_id_t nh_vrf_id)
{
	struct nexthop *nexthop;
	struct interface *ifp;

	nexthop = nexthop_new();
	nexthop->vrf_id = nh_vrf_id;
	nexthop->type = NEXTHOP_TYPE_IPV4_IFINDEX;
	nexthop->gate.ipv4 = *ipv4;
	if (src)
		nexthop->src.ipv4 = *src;
	nexthop->ifindex = ifindex;
	ifp = if_lookup_by_index(nexthop->ifindex, nh_vrf_id);
	/*Pending: need to think if null ifp here is ok during bootup?
	  There was a crash because ifp here was coming to be NULL */
	if (ifp)
		if (connected_is_unnumbered(ifp)
		    || CHECK_FLAG(re->flags, ZEBRA_FLAG_EVPN_ROUTE)
		    || CHECK_FLAG(re->flags, ZEBRA_FLAG_ONLINK)) {
			SET_FLAG(nexthop->flags, NEXTHOP_FLAG_ONLINK);
		}

	route_entry_nexthop_add(re, nexthop);

	return nexthop;
}

struct nexthop *route_entry_nexthop_ipv6_add(struct route_entry *re,
					     struct in6_addr *ipv6,
					     vrf_id_t nh_vrf_id)
{
	struct nexthop *nexthop;

	nexthop = nexthop_new();
	nexthop->vrf_id = nh_vrf_id;
	nexthop->type = NEXTHOP_TYPE_IPV6;
	nexthop->gate.ipv6 = *ipv6;

	route_entry_nexthop_add(re, nexthop);

	return nexthop;
}

struct nexthop *route_entry_nexthop_ipv6_ifindex_add(struct route_entry *re,
						     struct in6_addr *ipv6,
						     ifindex_t ifindex,
						     vrf_id_t nh_vrf_id)
{
	struct nexthop *nexthop;

	nexthop = nexthop_new();
	nexthop->vrf_id = nh_vrf_id;
	nexthop->type = NEXTHOP_TYPE_IPV6_IFINDEX;
	nexthop->gate.ipv6 = *ipv6;
	nexthop->ifindex = ifindex;
	if (CHECK_FLAG(re->flags, ZEBRA_FLAG_EVPN_ROUTE)
	    || CHECK_FLAG(re->flags, ZEBRA_FLAG_ONLINK)) {
		SET_FLAG(nexthop->flags, NEXTHOP_FLAG_ONLINK);
	}

	route_entry_nexthop_add(re, nexthop);

	return nexthop;
}

struct nexthop *route_entry_nexthop_blackhole_add(struct route_entry *re,
						  enum blackhole_type bh_type)
{
	struct nexthop *nexthop;

	nexthop = nexthop_new();
	nexthop->vrf_id = VRF_DEFAULT;
	nexthop->type = NEXTHOP_TYPE_BLACKHOLE;
	nexthop->bh_type = bh_type;

	route_entry_nexthop_add(re, nexthop);

	return nexthop;
}

static void nexthop_set_resolved(afi_t afi, const struct nexthop *newhop,
				 struct nexthop *nexthop)
{
	struct nexthop *resolved_hop;

	resolved_hop = nexthop_new();
	SET_FLAG(resolved_hop->flags, NEXTHOP_FLAG_ACTIVE);

	resolved_hop->vrf_id = nexthop->vrf_id;
	switch (newhop->type) {
	case NEXTHOP_TYPE_IPV4:
	case NEXTHOP_TYPE_IPV4_IFINDEX:
		/* If the resolving route specifies a gateway, use it */
		resolved_hop->type = newhop->type;
		resolved_hop->gate.ipv4 = newhop->gate.ipv4;

		if (newhop->ifindex) {
			resolved_hop->type = NEXTHOP_TYPE_IPV4_IFINDEX;
			resolved_hop->ifindex = newhop->ifindex;
		}
		break;
	case NEXTHOP_TYPE_IPV6:
	case NEXTHOP_TYPE_IPV6_IFINDEX:
		resolved_hop->type = newhop->type;
		resolved_hop->gate.ipv6 = newhop->gate.ipv6;

		if (newhop->ifindex) {
			resolved_hop->type = NEXTHOP_TYPE_IPV6_IFINDEX;
			resolved_hop->ifindex = newhop->ifindex;
		}
		break;
	case NEXTHOP_TYPE_IFINDEX:
		/* If the resolving route is an interface route,
		 * it means the gateway we are looking up is connected
		 * to that interface. (The actual network is _not_ onlink).
		 * Therefore, the resolved route should have the original
		 * gateway as nexthop as it is directly connected.
		 *
		 * On Linux, we have to set the onlink netlink flag because
		 * otherwise, the kernel won't accept the route.
		 */
		resolved_hop->flags |= NEXTHOP_FLAG_ONLINK;
		if (afi == AFI_IP) {
			resolved_hop->type = NEXTHOP_TYPE_IPV4_IFINDEX;
			resolved_hop->gate.ipv4 = nexthop->gate.ipv4;
		} else if (afi == AFI_IP6) {
			resolved_hop->type = NEXTHOP_TYPE_IPV6_IFINDEX;
			resolved_hop->gate.ipv6 = nexthop->gate.ipv6;
		}
		resolved_hop->ifindex = newhop->ifindex;
		break;
	case NEXTHOP_TYPE_BLACKHOLE:
		resolved_hop->type = NEXTHOP_TYPE_BLACKHOLE;
		resolved_hop->bh_type = nexthop->bh_type;
		break;
	}

	if (newhop->flags & NEXTHOP_FLAG_ONLINK)
		resolved_hop->flags |= NEXTHOP_FLAG_ONLINK;

	/* Copy labels of the resolved route */
	if (newhop->nh_label)
		nexthop_add_labels(resolved_hop, newhop->nh_label_type,
				   newhop->nh_label->num_labels,
				   &newhop->nh_label->label[0]);

	resolved_hop->rparent = nexthop;
	nexthop_add(&nexthop->resolved, resolved_hop);
}

/* If force flag is not set, do not modify falgs at all for uninstall
   the route from FIB. */
static int nexthop_active(afi_t afi, struct route_entry *re,
			  struct nexthop *nexthop, int set,
			  struct route_node *top)
{
	struct prefix p;
	struct route_table *table;
	struct route_node *rn;
	struct route_entry *match = NULL;
	int resolved;
	struct nexthop *newhop;
	struct interface *ifp;
	rib_dest_t *dest;

	if ((nexthop->type == NEXTHOP_TYPE_IPV4)
	    || nexthop->type == NEXTHOP_TYPE_IPV6)
		nexthop->ifindex = 0;

	if (set) {
		UNSET_FLAG(nexthop->flags, NEXTHOP_FLAG_RECURSIVE);
		nexthops_free(nexthop->resolved);
		nexthop->resolved = NULL;
		re->nexthop_mtu = 0;
	}

	/* Next hops (remote VTEPs) for EVPN routes are fully resolved. */
	if (CHECK_FLAG(nexthop->flags, NEXTHOP_FLAG_EVPN_RVTEP))
		return 1;

	/* Skip nexthops that have been filtered out due to route-map */
	/* The nexthops are specific to this route and so the same */
	/* nexthop for a different route may not have this flag set */
	if (CHECK_FLAG(nexthop->flags, NEXTHOP_FLAG_FILTERED)) {
		if (IS_ZEBRA_DEBUG_RIB_DETAILED)
			zlog_debug("\t%s: Nexthop Filtered",
				   __PRETTY_FUNCTION__);
		return 0;
	}

	/*
	 * Check to see if we should trust the passed in information
	 * for UNNUMBERED interfaces as that we won't find the GW
	 * address in the routing table.
	 */
	if (CHECK_FLAG(nexthop->flags, NEXTHOP_FLAG_ONLINK)) {
		ifp = if_lookup_by_index(nexthop->ifindex, nexthop->vrf_id);
		if ((ifp && connected_is_unnumbered(ifp))
		    || CHECK_FLAG(re->flags, ZEBRA_FLAG_ONLINK)) {
			if (if_is_operative(ifp))
				return 1;
			else {
				if (IS_ZEBRA_DEBUG_RIB_DETAILED)
					zlog_debug(
						"\t%s: Onlink and interface %s is not operative",
						__PRETTY_FUNCTION__, ifp->name);
				return 0;
			}
		} else {
			if (IS_ZEBRA_DEBUG_RIB_DETAILED)
				zlog_debug(
					"\t%s: Interface %s is not unnumbered",
					__PRETTY_FUNCTION__,
					ifp ? ifp->name : "Unknown");
			return 0;
		}
	}

	/* Make lookup prefix. */
	memset(&p, 0, sizeof(struct prefix));
	switch (afi) {
	case AFI_IP:
		p.family = AF_INET;
		p.prefixlen = IPV4_MAX_PREFIXLEN;
		p.u.prefix4 = nexthop->gate.ipv4;
		break;
	case AFI_IP6:
		p.family = AF_INET6;
		p.prefixlen = IPV6_MAX_PREFIXLEN;
		p.u.prefix6 = nexthop->gate.ipv6;
		break;
	default:
		assert(afi != AFI_IP && afi != AFI_IP6);
		break;
	}
	/* Lookup table.  */
	table = zebra_vrf_table(afi, SAFI_UNICAST, nexthop->vrf_id);
	if (!table) {
		if (IS_ZEBRA_DEBUG_RIB_DETAILED)
			zlog_debug("\t%s: Table not found",
				   __PRETTY_FUNCTION__);
		return 0;
	}

	rn = route_node_match(table, (struct prefix *)&p);
	while (rn) {
		route_unlock_node(rn);

		/* Lookup should halt if we've matched against ourselves ('top',
		 * if specified) - i.e., we cannot have a nexthop NH1 is
		 * resolved by a route NH1. The exception is if the route is a
		 * host route.
		 */
		if (top && rn == top)
			if (((afi == AFI_IP) && (rn->p.prefixlen != 32))
			    || ((afi == AFI_IP6) && (rn->p.prefixlen != 128))) {
				if (IS_ZEBRA_DEBUG_RIB_DETAILED)
					zlog_debug(
						"\t%s: Matched against ourself and prefix length is not max bit length",
						__PRETTY_FUNCTION__);
				return 0;
			}

		/* Pick up selected route. */
		/* However, do not resolve over default route unless explicitly
		 * allowed. */
		if (is_default_prefix(&rn->p)
		    && !rnh_resolve_via_default(p.family)) {
			if (IS_ZEBRA_DEBUG_RIB_DETAILED)
				zlog_debug(
					"\t:%s: Resolved against default route",
					__PRETTY_FUNCTION__);
			return 0;
		}

		dest = rib_dest_from_rnode(rn);
		if (dest && dest->selected_fib
		    && !CHECK_FLAG(dest->selected_fib->status,
				   ROUTE_ENTRY_REMOVED)
		    && dest->selected_fib->type != ZEBRA_ROUTE_TABLE)
			match = dest->selected_fib;

		/* If there is no selected route or matched route is EGP, go up
		   tree. */
		if (!match) {
			do {
				rn = rn->parent;
			} while (rn && rn->info == NULL);
			if (rn)
				route_lock_node(rn);

			continue;
		}

		if (match->type == ZEBRA_ROUTE_CONNECT) {
			/* Directly point connected route. */
			newhop = match->ng.nexthop;
			if (newhop) {
				if (nexthop->type == NEXTHOP_TYPE_IPV4
				    || nexthop->type == NEXTHOP_TYPE_IPV6)
					nexthop->ifindex = newhop->ifindex;
			}
			return 1;
		} else if (CHECK_FLAG(re->flags, ZEBRA_FLAG_ALLOW_RECURSION)) {
			resolved = 0;
			for (ALL_NEXTHOPS(match->ng, newhop)) {
				if (!CHECK_FLAG(newhop->flags,
						NEXTHOP_FLAG_FIB))
					continue;
				if (CHECK_FLAG(newhop->flags,
					       NEXTHOP_FLAG_RECURSIVE))
					continue;

				if (set) {
					SET_FLAG(nexthop->flags,
						 NEXTHOP_FLAG_RECURSIVE);
					SET_FLAG(re->status,
						 ROUTE_ENTRY_NEXTHOPS_CHANGED);
					nexthop_set_resolved(afi, newhop,
							     nexthop);
				}
				resolved = 1;
			}
			if (resolved && set)
				re->nexthop_mtu = match->mtu;
			if (!resolved && IS_ZEBRA_DEBUG_RIB_DETAILED)
				zlog_debug("\t%s: Recursion failed to find",
					   __PRETTY_FUNCTION__);
			return resolved;
		} else if (re->type == ZEBRA_ROUTE_STATIC) {
			resolved = 0;
			for (ALL_NEXTHOPS(match->ng, newhop)) {
				if (!CHECK_FLAG(newhop->flags,
						NEXTHOP_FLAG_FIB))
					continue;

				if (set) {
					SET_FLAG(nexthop->flags,
						 NEXTHOP_FLAG_RECURSIVE);
					nexthop_set_resolved(afi, newhop,
							     nexthop);
				}
				resolved = 1;
			}
			if (resolved && set)
				re->nexthop_mtu = match->mtu;

			if (!resolved && IS_ZEBRA_DEBUG_RIB_DETAILED)
				zlog_debug(
					"\t%s: Static route unable to resolve",
					__PRETTY_FUNCTION__);
			return resolved;
		} else {
			if (IS_ZEBRA_DEBUG_RIB_DETAILED) {
				zlog_debug("\t%s: Route Type %s has not turned on recursion",
					   __PRETTY_FUNCTION__,
					   zebra_route_string(re->type));
				if (re->type == ZEBRA_ROUTE_BGP &&
				    !CHECK_FLAG(re->flags, ZEBRA_FLAG_IBGP))
					zlog_debug("\tEBGP: see \"disable-ebgp-connected-route-check\" or \"disable-connected-check\"");
			}
			return 0;
		}
	}
	if (IS_ZEBRA_DEBUG_RIB_DETAILED)
		zlog_debug("\t%s: Nexthop did not lookup in table",
			   __PRETTY_FUNCTION__);
	return 0;
}

struct route_entry *rib_match(afi_t afi, safi_t safi, vrf_id_t vrf_id,
			      union g_addr *addr, struct route_node **rn_out)
{
	struct prefix p;
	struct route_table *table;
	struct route_node *rn;
	struct route_entry *match = NULL;
	struct nexthop *newhop;

	/* Lookup table.  */
	table = zebra_vrf_table(afi, safi, vrf_id);
	if (!table)
		return 0;

	memset(&p, 0, sizeof(struct prefix));
	p.family = afi;
	if (afi == AFI_IP) {
		p.u.prefix4 = addr->ipv4;
		p.prefixlen = IPV4_MAX_PREFIXLEN;
	} else {
		p.u.prefix6 = addr->ipv6;
		p.prefixlen = IPV6_MAX_PREFIXLEN;
	}

	rn = route_node_match(table, (struct prefix *)&p);

	while (rn) {
		rib_dest_t *dest;

		route_unlock_node(rn);

		dest = rib_dest_from_rnode(rn);
		if (dest && dest->selected_fib
		    && !CHECK_FLAG(dest->selected_fib->status,
				   ROUTE_ENTRY_REMOVED))
			match = dest->selected_fib;

		/* If there is no selected route or matched route is EGP, go up
		   tree. */
		if (!match) {
			do {
				rn = rn->parent;
			} while (rn && rn->info == NULL);
			if (rn)
				route_lock_node(rn);
		} else {
			if (match->type != ZEBRA_ROUTE_CONNECT) {
				int found = 0;
				for (ALL_NEXTHOPS(match->ng, newhop))
					if (CHECK_FLAG(newhop->flags,
						       NEXTHOP_FLAG_FIB)) {
						found = 1;
						break;
					}
				if (!found)
					return NULL;
			}

			if (rn_out)
				*rn_out = rn;
			return match;
		}
	}
	return NULL;
}

struct route_entry *rib_match_ipv4_multicast(vrf_id_t vrf_id,
					     struct in_addr addr,
					     struct route_node **rn_out)
{
	struct route_entry *re = NULL, *mre = NULL, *ure = NULL;
	struct route_node *m_rn = NULL, *u_rn = NULL;
	union g_addr gaddr = {.ipv4 = addr};

	switch (ipv4_multicast_mode) {
	case MCAST_MRIB_ONLY:
		return rib_match(AFI_IP, SAFI_MULTICAST, vrf_id, &gaddr,
				 rn_out);
	case MCAST_URIB_ONLY:
		return rib_match(AFI_IP, SAFI_UNICAST, vrf_id, &gaddr, rn_out);
	case MCAST_NO_CONFIG:
	case MCAST_MIX_MRIB_FIRST:
		re = mre = rib_match(AFI_IP, SAFI_MULTICAST, vrf_id, &gaddr,
				     &m_rn);
		if (!mre)
			re = ure = rib_match(AFI_IP, SAFI_UNICAST, vrf_id,
					     &gaddr, &u_rn);
		break;
	case MCAST_MIX_DISTANCE:
		mre = rib_match(AFI_IP, SAFI_MULTICAST, vrf_id, &gaddr, &m_rn);
		ure = rib_match(AFI_IP, SAFI_UNICAST, vrf_id, &gaddr, &u_rn);
		if (mre && ure)
			re = ure->distance < mre->distance ? ure : mre;
		else if (mre)
			re = mre;
		else if (ure)
			re = ure;
		break;
	case MCAST_MIX_PFXLEN:
		mre = rib_match(AFI_IP, SAFI_MULTICAST, vrf_id, &gaddr, &m_rn);
		ure = rib_match(AFI_IP, SAFI_UNICAST, vrf_id, &gaddr, &u_rn);
		if (mre && ure)
			re = u_rn->p.prefixlen > m_rn->p.prefixlen ? ure : mre;
		else if (mre)
			re = mre;
		else if (ure)
			re = ure;
		break;
	}

	if (rn_out)
		*rn_out = (re == mre) ? m_rn : u_rn;

	if (IS_ZEBRA_DEBUG_RIB) {
		char buf[BUFSIZ];
		inet_ntop(AF_INET, &addr, buf, BUFSIZ);

		zlog_debug("%s: %s: vrf: %u found %s, using %s",
			   __func__, buf, vrf_id,
			   mre ? (ure ? "MRIB+URIB" : "MRIB")
			       : ure ? "URIB" : "nothing",
			   re == ure ? "URIB" : re == mre ? "MRIB" : "none");
	}
	return re;
}

void multicast_mode_ipv4_set(enum multicast_mode mode)
{
	if (IS_ZEBRA_DEBUG_RIB)
		zlog_debug("%s: multicast lookup mode set (%d)", __func__,
			   mode);
	ipv4_multicast_mode = mode;
}

enum multicast_mode multicast_mode_ipv4_get(void)
{
	return ipv4_multicast_mode;
}

struct route_entry *rib_lookup_ipv4(struct prefix_ipv4 *p, vrf_id_t vrf_id)
{
	struct route_table *table;
	struct route_node *rn;
	struct route_entry *match = NULL;
	struct nexthop *nexthop;
	rib_dest_t *dest;

	/* Lookup table.  */
	table = zebra_vrf_table(AFI_IP, SAFI_UNICAST, vrf_id);
	if (!table)
		return 0;

	rn = route_node_lookup(table, (struct prefix *)p);

	/* No route for this prefix. */
	if (!rn)
		return NULL;

	/* Unlock node. */
	route_unlock_node(rn);
	dest = rib_dest_from_rnode(rn);

	if (dest && dest->selected_fib
	    && !CHECK_FLAG(dest->selected_fib->status, ROUTE_ENTRY_REMOVED))
		match = dest->selected_fib;

	if (!match)
		return NULL;

	if (match->type == ZEBRA_ROUTE_CONNECT)
		return match;

	for (ALL_NEXTHOPS(match->ng, nexthop))
		if (CHECK_FLAG(nexthop->flags, NEXTHOP_FLAG_FIB))
			return match;

	return NULL;
}

/*
 * This clone function, unlike its original rib_lookup_ipv4(), checks
 * if specified IPv4 route record (prefix/mask -> gate) exists in
 * the whole RIB and has ROUTE_ENTRY_SELECTED_FIB set.
 *
 * Return values:
 * -1: error
 * 0: exact match found
 * 1: a match was found with a different gate
 * 2: connected route found
 * 3: no matches found
 */
int rib_lookup_ipv4_route(struct prefix_ipv4 *p, union sockunion *qgate,
			  vrf_id_t vrf_id)
{
	struct route_table *table;
	struct route_node *rn;
	struct route_entry *match = NULL;
	struct nexthop *nexthop;
	int nexthops_active;
	rib_dest_t *dest;

	/* Lookup table.  */
	table = zebra_vrf_table(AFI_IP, SAFI_UNICAST, vrf_id);
	if (!table)
		return ZEBRA_RIB_LOOKUP_ERROR;

	/* Scan the RIB table for exactly matching RIB entry. */
	rn = route_node_lookup(table, (struct prefix *)p);

	/* No route for this prefix. */
	if (!rn)
		return ZEBRA_RIB_NOTFOUND;

	/* Unlock node. */
	route_unlock_node(rn);
	dest = rib_dest_from_rnode(rn);

	/* Find out if a "selected" RR for the discovered RIB entry exists ever.
	 */
	if (dest && dest->selected_fib
	    && !CHECK_FLAG(dest->selected_fib->status, ROUTE_ENTRY_REMOVED))
		match = dest->selected_fib;

	/* None such found :( */
	if (!match)
		return ZEBRA_RIB_NOTFOUND;

	if (match->type == ZEBRA_ROUTE_CONNECT)
		return ZEBRA_RIB_FOUND_CONNECTED;

	/* Ok, we have a cood candidate, let's check it's nexthop list... */
	nexthops_active = 0;
	for (ALL_NEXTHOPS(match->ng, nexthop))
		if (CHECK_FLAG(nexthop->flags, NEXTHOP_FLAG_FIB)) {
			nexthops_active = 1;
			if (nexthop->gate.ipv4.s_addr == sockunion2ip(qgate))
				return ZEBRA_RIB_FOUND_EXACT;
			if (IS_ZEBRA_DEBUG_RIB) {
				char gate_buf[INET_ADDRSTRLEN],
					qgate_buf[INET_ADDRSTRLEN];
				inet_ntop(AF_INET, &nexthop->gate.ipv4.s_addr,
					  gate_buf, INET_ADDRSTRLEN);
				inet_ntop(AF_INET, &sockunion2ip(qgate),
					  qgate_buf, INET_ADDRSTRLEN);
				zlog_debug("%s: qgate == %s, %s == %s",
					   __func__, qgate_buf,
					   nexthop->rparent ? "rgate" : "gate",
					   gate_buf);
			}
		}

	if (nexthops_active)
		return ZEBRA_RIB_FOUND_NOGATE;

	return ZEBRA_RIB_NOTFOUND;
}

#define RIB_SYSTEM_ROUTE(R)                                                    \
	((R)->type == ZEBRA_ROUTE_KERNEL || (R)->type == ZEBRA_ROUTE_CONNECT)

#define RIB_KERNEL_ROUTE(R)						\
	((R)->type == ZEBRA_ROUTE_KERNEL)

/* This function verifies reachability of one given nexthop, which can be
 * numbered or unnumbered, IPv4 or IPv6. The result is unconditionally stored
 * in nexthop->flags field. If the 4th parameter, 'set', is non-zero,
 * nexthop->ifindex will be updated appropriately as well.
 * An existing route map can turn (otherwise active) nexthop into inactive, but
 * not vice versa.
 *
 * The return value is the final value of 'ACTIVE' flag.
 */

static unsigned nexthop_active_check(struct route_node *rn,
				     struct route_entry *re,
				     struct nexthop *nexthop, int set)
{
	struct interface *ifp;
	route_map_result_t ret = RMAP_MATCH;
	int family;
	char buf[SRCDEST2STR_BUFFER];
	const struct prefix *p, *src_p;
	struct zebra_vrf *zvrf;

	srcdest_rnode_prefixes(rn, &p, &src_p);

	if (rn->p.family == AF_INET)
		family = AFI_IP;
	else if (rn->p.family == AF_INET6)
		family = AFI_IP6;
	else
		family = 0;
	switch (nexthop->type) {
	case NEXTHOP_TYPE_IFINDEX:
		ifp = if_lookup_by_index(nexthop->ifindex, nexthop->vrf_id);
		if (ifp && if_is_operative(ifp))
			SET_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE);
		else
			UNSET_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE);
		break;
	case NEXTHOP_TYPE_IPV4:
	case NEXTHOP_TYPE_IPV4_IFINDEX:
		family = AFI_IP;
		if (nexthop_active(AFI_IP, re, nexthop, set, rn))
			SET_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE);
		else
			UNSET_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE);
		break;
	case NEXTHOP_TYPE_IPV6:
		family = AFI_IP6;
		if (nexthop_active(AFI_IP6, re, nexthop, set, rn))
			SET_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE);
		else
			UNSET_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE);
		break;
	case NEXTHOP_TYPE_IPV6_IFINDEX:
		/* RFC 5549, v4 prefix with v6 NH */
		if (rn->p.family != AF_INET)
			family = AFI_IP6;
		if (IN6_IS_ADDR_LINKLOCAL(&nexthop->gate.ipv6)) {
			ifp = if_lookup_by_index(nexthop->ifindex,
						 nexthop->vrf_id);
			if (ifp && if_is_operative(ifp))
				SET_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE);
			else
				UNSET_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE);
		} else {
			if (nexthop_active(AFI_IP6, re, nexthop, set, rn))
				SET_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE);
			else
				UNSET_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE);
		}
		break;
	case NEXTHOP_TYPE_BLACKHOLE:
		SET_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE);
		break;
	default:
		break;
	}
	if (!CHECK_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE)) {
		if (IS_ZEBRA_DEBUG_RIB_DETAILED)
			zlog_debug("\t%s: Unable to find a active nexthop",
				   __PRETTY_FUNCTION__);
		return 0;
	}

	/* XXX: What exactly do those checks do? Do we support
	 * e.g. IPv4 routes with IPv6 nexthops or vice versa?
	 */
	if (RIB_SYSTEM_ROUTE(re) || (family == AFI_IP && p->family != AF_INET)
	    || (family == AFI_IP6 && p->family != AF_INET6))
		return CHECK_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE);

	/* The original code didn't determine the family correctly
	 * e.g. for NEXTHOP_TYPE_IFINDEX. Retrieve the correct afi
	 * from the rib_table_info in those cases.
	 * Possibly it may be better to use only the rib_table_info
	 * in every case.
	 */
	if (!family) {
		rib_table_info_t *info;

		info = srcdest_rnode_table_info(rn);
		family = info->afi;
	}

	memset(&nexthop->rmap_src.ipv6, 0, sizeof(union g_addr));

	zvrf = zebra_vrf_lookup_by_id(nexthop->vrf_id);
	if (!zvrf) {
		if (IS_ZEBRA_DEBUG_RIB_DETAILED)
			zlog_debug("\t%s: zvrf is NULL", __PRETTY_FUNCTION__);
		return CHECK_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE);
	}

	/* It'll get set if required inside */
	ret = zebra_route_map_check(family, re->type, re->instance, p,
				    nexthop, zvrf, re->tag);
	if (ret == RMAP_DENYMATCH) {
		if (IS_ZEBRA_DEBUG_RIB) {
			srcdest_rnode2str(rn, buf, sizeof(buf));
			zlog_debug(
				"%u:%s: Filtering out with NH out %s due to route map",
				re->vrf_id, buf,
				ifindex2ifname(nexthop->ifindex,
					       nexthop->vrf_id));
		}
		UNSET_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE);
	}
	return CHECK_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE);
}

/* Iterate over all nexthops of the given RIB entry and refresh their
 * ACTIVE flag. re->nexthop_active_num is updated accordingly. If any
 * nexthop is found to toggle the ACTIVE flag, the whole re structure
 * is flagged with ROUTE_ENTRY_CHANGED. The 4th 'set' argument is
 * transparently passed to nexthop_active_check().
 *
 * Return value is the new number of active nexthops.
 */

static int nexthop_active_update(struct route_node *rn, struct route_entry *re,
				 int set)
{
	struct nexthop *nexthop;
	union g_addr prev_src;
	unsigned int prev_active, new_active, old_num_nh;
	ifindex_t prev_index;

	old_num_nh = re->nexthop_active_num;

	re->nexthop_active_num = 0;
	UNSET_FLAG(re->status, ROUTE_ENTRY_CHANGED);

	for (nexthop = re->ng.nexthop; nexthop; nexthop = nexthop->next) {
		/* No protocol daemon provides src and so we're skipping
		 * tracking it */
		prev_src = nexthop->rmap_src;
		prev_active = CHECK_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE);
		prev_index = nexthop->ifindex;
		if ((new_active = nexthop_active_check(rn, re, nexthop, set)))
			re->nexthop_active_num++;
		/* Don't allow src setting on IPv6 addr for now */
		if (prev_active != new_active || prev_index != nexthop->ifindex
		    || ((nexthop->type >= NEXTHOP_TYPE_IFINDEX
			 && nexthop->type < NEXTHOP_TYPE_IPV6)
			&& prev_src.ipv4.s_addr
				   != nexthop->rmap_src.ipv4.s_addr)
		    || ((nexthop->type >= NEXTHOP_TYPE_IPV6
			 && nexthop->type < NEXTHOP_TYPE_BLACKHOLE)
			&& !(IPV6_ADDR_SAME(&prev_src.ipv6,
					    &nexthop->rmap_src.ipv6)))) {
			SET_FLAG(re->status, ROUTE_ENTRY_CHANGED);
			SET_FLAG(re->status, ROUTE_ENTRY_NEXTHOPS_CHANGED);
		}
	}

	if (old_num_nh != re->nexthop_active_num)
		SET_FLAG(re->status, ROUTE_ENTRY_CHANGED);

	if (CHECK_FLAG(re->status, ROUTE_ENTRY_CHANGED)) {
		SET_FLAG(re->status, ROUTE_ENTRY_NEXTHOPS_CHANGED);
	}

	return re->nexthop_active_num;
}

/*
 * Is this RIB labeled-unicast? It must be of type BGP and all paths
 * (nexthops) must have a label.
 */
int zebra_rib_labeled_unicast(struct route_entry *re)
{
	struct nexthop *nexthop = NULL;

	if (re->type != ZEBRA_ROUTE_BGP)
		return 0;

	for (ALL_NEXTHOPS(re->ng, nexthop))
		if (!nexthop->nh_label || !nexthop->nh_label->num_labels)
			return 0;

	return 1;
}

/* Update flag indicates whether this is a "replace" or not. Currently, this
 * is only used for IPv4.
 */
void rib_install_kernel(struct route_node *rn, struct route_entry *re,
			struct route_entry *old)
{
	struct nexthop *nexthop;
	rib_table_info_t *info = srcdest_rnode_table_info(rn);
	struct zebra_vrf *zvrf = vrf_info_lookup(re->vrf_id);
	const struct prefix *p, *src_p;
	enum zebra_dplane_result ret;

	rib_dest_t *dest = rib_dest_from_rnode(rn);

	srcdest_rnode_prefixes(rn, &p, &src_p);

	if (info->safi != SAFI_UNICAST) {
		for (ALL_NEXTHOPS(re->ng, nexthop))
			SET_FLAG(nexthop->flags, NEXTHOP_FLAG_FIB);
		return;
	} else {
		struct nexthop *prev;

		for (ALL_NEXTHOPS(re->ng, nexthop)) {
			UNSET_FLAG (nexthop->flags, NEXTHOP_FLAG_DUPLICATE);
			for (ALL_NEXTHOPS(re->ng, prev)) {
				if (prev == nexthop)
					break;
				if (nexthop_same_firsthop(nexthop, prev)) {
					SET_FLAG(nexthop->flags,
						 NEXTHOP_FLAG_DUPLICATE);
					break;
				}
			}
		}
	}

	/*
	 * If this is a replace to a new RE let the originator of the RE
	 * know that they've lost
	 */
	if (old && (old != re) && (old->type != re->type))
		zsend_route_notify_owner(old, p, ZAPI_ROUTE_BETTER_ADMIN_WON);

	/* Update fib selection */
	dest->selected_fib = re;

	/*
	 * Make sure we update the FPM any time we send new information to
	 * the kernel.
	 */
	hook_call(rib_update, rn, "installing in kernel");

	/* Send add or update */
	if (old && (old != re))
		ret = dplane_route_update(rn, re, old);
	else
		ret = dplane_route_add(rn, re);

	switch (ret) {
	case ZEBRA_DPLANE_REQUEST_QUEUED:
		if (zvrf)
			zvrf->installs_queued++;
		break;
	case ZEBRA_DPLANE_REQUEST_FAILURE:
	{
		char str[SRCDEST2STR_BUFFER];

		srcdest_rnode2str(rn, str, sizeof(str));
		flog_err(EC_ZEBRA_DP_INSTALL_FAIL,
			 "%u:%s: Failed to enqueue dataplane install",
			 re->vrf_id, str);
		break;
	}
	case ZEBRA_DPLANE_REQUEST_SUCCESS:
		if (zvrf)
			zvrf->installs++;
		break;
	}

	return;
}

/* Uninstall the route from kernel. */
void rib_uninstall_kernel(struct route_node *rn, struct route_entry *re)
{
	struct nexthop *nexthop;
	rib_table_info_t *info = srcdest_rnode_table_info(rn);
	struct zebra_vrf *zvrf = vrf_info_lookup(re->vrf_id);

	if (info->safi != SAFI_UNICAST) {
		for (ALL_NEXTHOPS(re->ng, nexthop))
			UNSET_FLAG(nexthop->flags, NEXTHOP_FLAG_FIB);
		return;
	}

	/*
	 * Make sure we update the FPM any time we send new information to
	 * the dataplane.
	 */
	hook_call(rib_update, rn, "uninstalling from kernel");

	switch (dplane_route_delete(rn, re)) {
	case ZEBRA_DPLANE_REQUEST_QUEUED:
		if (zvrf)
			zvrf->removals_queued++;
		break;
	case ZEBRA_DPLANE_REQUEST_FAILURE:
	{
		char str[SRCDEST2STR_BUFFER];

		srcdest_rnode2str(rn, str, sizeof(str));
		flog_err(EC_ZEBRA_DP_INSTALL_FAIL,
			 "%u:%s: Failed to enqueue dataplane uninstall",
			 re->vrf_id, str);
		break;
	}
	case ZEBRA_DPLANE_REQUEST_SUCCESS:
		if (zvrf)
			zvrf->removals++;
		break;
	}

	return;
}

/* Uninstall the route from kernel. */
static void rib_uninstall(struct route_node *rn, struct route_entry *re)
{
	rib_table_info_t *info = srcdest_rnode_table_info(rn);
	rib_dest_t *dest = rib_dest_from_rnode(rn);
	struct nexthop *nexthop;

	if (dest && dest->selected_fib == re) {
		if (info->safi == SAFI_UNICAST)
			hook_call(rib_update, rn, "rib_uninstall");

		/* If labeled-unicast route, uninstall transit LSP. */
		if (zebra_rib_labeled_unicast(re))
			zebra_mpls_lsp_uninstall(info->zvrf, rn, re);

		if (!RIB_SYSTEM_ROUTE(re))
			rib_uninstall_kernel(rn, re);

		dest->selected_fib = NULL;

		for (ALL_NEXTHOPS(re->ng, nexthop))
			UNSET_FLAG(nexthop->flags, NEXTHOP_FLAG_FIB);
	}

	if (CHECK_FLAG(re->flags, ZEBRA_FLAG_SELECTED)) {
		const struct prefix *p, *src_p;

		srcdest_rnode_prefixes(rn, &p, &src_p);

		redistribute_delete(p, src_p, re);
		UNSET_FLAG(re->flags, ZEBRA_FLAG_SELECTED);
	}
}

/*
 * rib_can_delete_dest
 *
 * Returns TRUE if the given dest can be deleted from the table.
 */
static int rib_can_delete_dest(rib_dest_t *dest)
{
	if (dest->routes) {
		return 0;
	}

	/*
	 * Don't delete the dest if we have to update the FPM about this
	 * prefix.
	 */
	if (CHECK_FLAG(dest->flags, RIB_DEST_UPDATE_FPM)
	    || CHECK_FLAG(dest->flags, RIB_DEST_SENT_TO_FPM))
		return 0;

	return 1;
}

/*
 * rib_gc_dest
 *
 * Garbage collect the rib dest corresponding to the given route node
 * if appropriate.
 *
 * Returns TRUE if the dest was deleted, FALSE otherwise.
 */
int rib_gc_dest(struct route_node *rn)
{
	rib_dest_t *dest;

	dest = rib_dest_from_rnode(rn);
	if (!dest)
		return 0;

	if (!rib_can_delete_dest(dest))
		return 0;

	if (IS_ZEBRA_DEBUG_RIB) {
		struct zebra_vrf *zvrf;

		zvrf = rib_dest_vrf(dest);
		rnode_debug(rn, zvrf_id(zvrf), "removing dest from table");
	}

	dest->rnode = NULL;
	XFREE(MTYPE_RIB_DEST, dest);
	rn->info = NULL;

	/*
	 * Release the one reference that we keep on the route node.
	 */
	route_unlock_node(rn);
	return 1;
}

static void rib_process_add_fib(struct zebra_vrf *zvrf, struct route_node *rn,
				struct route_entry *new)
{
	rib_dest_t *dest = rib_dest_from_rnode(rn);

	hook_call(rib_update, rn, "new route selected");

	/* Update real nexthop. This may actually determine if nexthop is active
	 * or not. */
	if (!nexthop_active_update(rn, new, 1)) {
		UNSET_FLAG(new->status, ROUTE_ENTRY_CHANGED);
		return;
	}

	if (IS_ZEBRA_DEBUG_RIB) {
		char buf[SRCDEST2STR_BUFFER];
		srcdest_rnode2str(rn, buf, sizeof(buf));
		zlog_debug("%u:%s: Adding route rn %p, re %p (type %d)",
			   zvrf_id(zvrf), buf, rn, new, new->type);
	}

	/* If labeled-unicast route, install transit LSP. */
	if (zebra_rib_labeled_unicast(new))
		zebra_mpls_lsp_install(zvrf, rn, new);

	if (!RIB_SYSTEM_ROUTE(new))
		rib_install_kernel(rn, new, NULL);
	else
		dest->selected_fib = new;

	UNSET_FLAG(new->status, ROUTE_ENTRY_CHANGED);
}

static void rib_process_del_fib(struct zebra_vrf *zvrf, struct route_node *rn,
				struct route_entry *old)
{
	rib_dest_t *dest = rib_dest_from_rnode(rn);
	hook_call(rib_update, rn, "removing existing route");

	/* Uninstall from kernel. */
	if (IS_ZEBRA_DEBUG_RIB) {
		char buf[SRCDEST2STR_BUFFER];
		srcdest_rnode2str(rn, buf, sizeof(buf));
		zlog_debug("%u:%s: Deleting route rn %p, re %p (type %d)",
			   zvrf_id(zvrf), buf, rn, old, old->type);
	}

	/* If labeled-unicast route, uninstall transit LSP. */
	if (zebra_rib_labeled_unicast(old))
		zebra_mpls_lsp_uninstall(zvrf, rn, old);

	if (!RIB_SYSTEM_ROUTE(old))
		rib_uninstall_kernel(rn, old);
	else {
		/*
		 * We are setting this to NULL here
		 * because that is what we traditionally
		 * have been doing.  I am not positive
		 * that this is the right thing to do
		 * but let's leave the code alone
		 * for the RIB_SYSTEM_ROUTE case
		 */
		dest->selected_fib = NULL;
	}

	/* Update nexthop for route, reset changed flag. */
	/* Note: this code also handles the Linux case when an interface goes
	 * down, causing the kernel to delete routes without sending DELROUTE
	 * notifications
	 */
	if (!nexthop_active_update(rn, old, 1) &&
	    (RIB_KERNEL_ROUTE(old)))
		SET_FLAG(old->status, ROUTE_ENTRY_REMOVED);
	else
		UNSET_FLAG(old->status, ROUTE_ENTRY_CHANGED);
}

static void rib_process_update_fib(struct zebra_vrf *zvrf,
				   struct route_node *rn,
				   struct route_entry *old,
				   struct route_entry *new)
{
	struct nexthop *nexthop = NULL;
	int nh_active = 0;
	rib_dest_t *dest = rib_dest_from_rnode(rn);

	/*
	 * We have to install or update if a new route has been selected or
	 * something has changed.
	 */
	if (new != old || CHECK_FLAG(new->status, ROUTE_ENTRY_CHANGED)) {
		hook_call(rib_update, rn, "updating existing route");

		/* Update the nexthop; we could determine here that nexthop is
		 * inactive. */
		if (nexthop_active_update(rn, new, 1))
			nh_active = 1;

		/* If nexthop is active, install the selected route, if
		 * appropriate. If
		 * the install succeeds, cleanup flags for prior route, if
		 * different from
		 * newly selected.
		 */
		if (nh_active) {
			if (IS_ZEBRA_DEBUG_RIB) {
				char buf[SRCDEST2STR_BUFFER];
				srcdest_rnode2str(rn, buf, sizeof(buf));
				if (new != old)
					zlog_debug(
						"%u:%s: Updating route rn %p, re %p (type %d) "
						"old %p (type %d)",
						zvrf_id(zvrf), buf, rn, new,
						new->type, old, old->type);
				else
					zlog_debug(
						"%u:%s: Updating route rn %p, re %p (type %d)",
						zvrf_id(zvrf), buf, rn, new,
						new->type);
			}

			/* If labeled-unicast route, uninstall transit LSP. */
			if (zebra_rib_labeled_unicast(old))
				zebra_mpls_lsp_uninstall(zvrf, rn, old);

			/* Non-system route should be installed. */
			if (!RIB_SYSTEM_ROUTE(new)) {
				/* If labeled-unicast route, install transit
				 * LSP. */
				if (zebra_rib_labeled_unicast(new))
					zebra_mpls_lsp_install(zvrf, rn, new);

				rib_install_kernel(rn, new, old);
			} else {
				/*
				 * We do not need to install the
				 * selected route because it
				 * is already isntalled by
				 * the system( ie not us )
				 * so just mark it as winning
				 * we do need to ensure that
				 * if we uninstall a route
				 * from ourselves we don't
				 * over write this pointer
				 */
				dest->selected_fib = NULL;
			}
			/* If install succeeded or system route, cleanup flags
			 * for prior route. */
			if (new != old) {
				if (RIB_SYSTEM_ROUTE(new)) {
					if (!RIB_SYSTEM_ROUTE(old))
						rib_uninstall_kernel(rn, old);
				} else {
					for (nexthop = old->ng.nexthop; nexthop;
					     nexthop = nexthop->next)
						UNSET_FLAG(nexthop->flags,
							   NEXTHOP_FLAG_FIB);
				}
			}
		}

		/*
		 * If nexthop for selected route is not active or install
		 * failed, we
		 * may need to uninstall and delete for redistribution.
		 */
		if (!nh_active) {
			if (IS_ZEBRA_DEBUG_RIB) {
				char buf[SRCDEST2STR_BUFFER];
				srcdest_rnode2str(rn, buf, sizeof(buf));
				if (new != old)
					zlog_debug(
						"%u:%s: Deleting route rn %p, re %p (type %d) "
						"old %p (type %d) - nexthop inactive",
						zvrf_id(zvrf), buf, rn, new,
						new->type, old, old->type);
				else
					zlog_debug(
						"%u:%s: Deleting route rn %p, re %p (type %d) - nexthop inactive",
						zvrf_id(zvrf), buf, rn, new,
						new->type);
			}

			/* If labeled-unicast route, uninstall transit LSP. */
			if (zebra_rib_labeled_unicast(old))
				zebra_mpls_lsp_uninstall(zvrf, rn, old);

			if (!RIB_SYSTEM_ROUTE(old))
				rib_uninstall_kernel(rn, old);
			else
				dest->selected_fib = NULL;
		}
	} else {
		/*
		 * Same route selected; check if in the FIB and if not,
		 * re-install. This
		 * is housekeeping code to deal with race conditions in kernel
		 * with linux
		 * netlink reporting interface up before IPv4 or IPv6 protocol
		 * is ready
		 * to add routes.
		 */
		if (!RIB_SYSTEM_ROUTE(new)) {
			bool in_fib = false;

			for (ALL_NEXTHOPS(new->ng, nexthop))
				if (CHECK_FLAG(nexthop->flags,
					       NEXTHOP_FLAG_FIB)) {
					in_fib = true;
					break;
				}
			if (!in_fib)
				rib_install_kernel(rn, new, NULL);
		}
	}

	/* Update prior route. */
	if (new != old) {
		/* Set real nexthop. */
		nexthop_active_update(rn, old, 1);
		UNSET_FLAG(old->status, ROUTE_ENTRY_CHANGED);
	}

	/* Clear changed flag. */
	UNSET_FLAG(new->status, ROUTE_ENTRY_CHANGED);
}

/* Check if 'alternate' RIB entry is better than 'current'. */
static struct route_entry *rib_choose_best(struct route_entry *current,
					   struct route_entry *alternate)
{
	if (current == NULL)
		return alternate;

	/* filter route selection in following order:
	 * - connected beats other types
	 * - if both connected, loopback or vrf wins
	 * - lower distance beats higher
	 * - lower metric beats higher for equal distance
	 * - last, hence oldest, route wins tie break.
	 */

	/* Connected routes. Check to see if either are a vrf
	 * or loopback interface.  If not, pick the last connected
	 * route of the set of lowest metric connected routes.
	 */
	if (alternate->type == ZEBRA_ROUTE_CONNECT) {
		if (current->type != ZEBRA_ROUTE_CONNECT)
			return alternate;

		/* both are connected.  are either loop or vrf? */
		struct nexthop *nexthop = NULL;

		for (ALL_NEXTHOPS(alternate->ng, nexthop)) {
			if (if_is_loopback_or_vrf(if_lookup_by_index(
				    nexthop->ifindex, alternate->vrf_id)))
				return alternate;
		}

		for (ALL_NEXTHOPS(current->ng, nexthop)) {
			if (if_is_loopback_or_vrf(if_lookup_by_index(
				    nexthop->ifindex, current->vrf_id)))
				return current;
		}

		/* Neither are loop or vrf so pick best metric  */
		if (alternate->metric <= current->metric)
			return alternate;

		return current;
	}

	if (current->type == ZEBRA_ROUTE_CONNECT)
		return current;

	/* higher distance loses */
	if (alternate->distance < current->distance)
		return alternate;
	if (current->distance < alternate->distance)
		return current;

	/* metric tie-breaks equal distance */
	if (alternate->metric <= current->metric)
		return alternate;

	return current;
}

/* Core function for processing routing information base. */
static void rib_process(struct route_node *rn)
{
	struct route_entry *re;
	struct route_entry *next;
	struct route_entry *old_selected = NULL;
	struct route_entry *new_selected = NULL;
	struct route_entry *old_fib = NULL;
	struct route_entry *new_fib = NULL;
	struct route_entry *best = NULL;
	char buf[SRCDEST2STR_BUFFER];
	rib_dest_t *dest;
	struct zebra_vrf *zvrf = NULL;
	const struct prefix *p, *src_p;

	srcdest_rnode_prefixes(rn, &p, &src_p);
	vrf_id_t vrf_id = VRF_UNKNOWN;

	assert(rn);

	dest = rib_dest_from_rnode(rn);
	if (dest) {
		zvrf = rib_dest_vrf(dest);
		vrf_id = zvrf_id(zvrf);
	}

	if (IS_ZEBRA_DEBUG_RIB)
		srcdest_rnode2str(rn, buf, sizeof(buf));

	if (IS_ZEBRA_DEBUG_RIB_DETAILED)
		zlog_debug("%u:%s: Processing rn %p", vrf_id, buf, rn);

	/*
	 * we can have rn's that have a NULL info pointer
	 * (dest).  As such let's not let the deref happen
	 * additionally we know RNODE_FOREACH_RE_SAFE
	 * will not iterate so we are ok.
	 */
	if (dest)
		old_fib = dest->selected_fib;

	RNODE_FOREACH_RE_SAFE (rn, re, next) {
		if (IS_ZEBRA_DEBUG_RIB_DETAILED)
			zlog_debug(
				"%u:%s: Examine re %p (type %d) status %x flags %x "
				"dist %d metric %d",
				vrf_id, buf, re, re->type, re->status,
				re->flags, re->distance, re->metric);

		UNSET_FLAG(re->status, ROUTE_ENTRY_NEXTHOPS_CHANGED);

		/* Currently selected re. */
		if (CHECK_FLAG(re->flags, ZEBRA_FLAG_SELECTED)) {
			assert(old_selected == NULL);
			old_selected = re;
		}

		/* Skip deleted entries from selection */
		if (CHECK_FLAG(re->status, ROUTE_ENTRY_REMOVED))
			continue;

		/* Skip unreachable nexthop. */
		/* This first call to nexthop_active_update is merely to
		 * determine if
		 * there's any change to nexthops associated with this RIB
		 * entry. Now,
		 * rib_process() can be invoked due to an external event such as
		 * link
		 * down or due to next-hop-tracking evaluation. In the latter
		 * case,
		 * a decision has already been made that the NHs have changed.
		 * So, no
		 * need to invoke a potentially expensive call again. Further,
		 * since
		 * the change might be in a recursive NH which is not caught in
		 * the nexthop_active_update() code. Thus, we might miss changes
		 * to
		 * recursive NHs.
		 */
		if (!CHECK_FLAG(re->status, ROUTE_ENTRY_CHANGED)
		    && !nexthop_active_update(rn, re, 0)) {
			if (re->type == ZEBRA_ROUTE_TABLE) {
				/* XXX: HERE BE DRAGONS!!!!!
				 * In all honesty, I have not yet figured out
				 * what this part
				 * does or why the ROUTE_ENTRY_CHANGED test
				 * above is correct
				 * or why we need to delete a route here, and
				 * also not whether
				 * this concerns both selected and fib route, or
				 * only selected
				 * or only fib */
				/* This entry was denied by the 'ip protocol
				 * table' route-map, we
				 * need to delete it */
				if (re != old_selected) {
					if (IS_ZEBRA_DEBUG_RIB)
						zlog_debug(
							"%s: %u:%s: imported via import-table but denied "
							"by the ip protocol table route-map",
							__func__, vrf_id, buf);
					rib_unlink(rn, re);
				} else
					SET_FLAG(re->status,
						 ROUTE_ENTRY_REMOVED);
			}

			continue;
		}

		/* Infinite distance. */
		if (re->distance == DISTANCE_INFINITY) {
			UNSET_FLAG(re->status, ROUTE_ENTRY_CHANGED);
			continue;
		}

		if (CHECK_FLAG(re->flags, ZEBRA_FLAG_FIB_OVERRIDE)) {
			best = rib_choose_best(new_fib, re);
			if (new_fib && best != new_fib)
				UNSET_FLAG(new_fib->status,
					   ROUTE_ENTRY_CHANGED);
			new_fib = best;
		} else {
			best = rib_choose_best(new_selected, re);
			if (new_selected && best != new_selected)
				UNSET_FLAG(new_selected->status,
					   ROUTE_ENTRY_CHANGED);
			new_selected = best;
		}
		if (best != re)
			UNSET_FLAG(re->status, ROUTE_ENTRY_CHANGED);
	} /* RNODE_FOREACH_RE */

	/* If no FIB override route, use the selected route also for FIB */
	if (new_fib == NULL)
		new_fib = new_selected;

	/* After the cycle is finished, the following pointers will be set:
	 * old_selected --- RE entry currently having SELECTED
	 * new_selected --- RE entry that is newly SELECTED
	 * old_fib      --- RE entry currently in kernel FIB
	 * new_fib      --- RE entry that is newly to be in kernel FIB
	 *
	 * new_selected will get SELECTED flag, and is going to be redistributed
	 * the zclients. new_fib (which can be new_selected) will be installed
	 * in kernel.
	 */

	if (IS_ZEBRA_DEBUG_RIB_DETAILED) {
		zlog_debug(
			"%u:%s: After processing: old_selected %p new_selected %p old_fib %p new_fib %p",
			vrf_id, buf, (void *)old_selected, (void *)new_selected,
			(void *)old_fib, (void *)new_fib);
	}

	/* Buffer ROUTE_ENTRY_CHANGED here, because it will get cleared if
	 * fib == selected */
	bool selected_changed = new_selected && CHECK_FLAG(new_selected->status,
							   ROUTE_ENTRY_CHANGED);

	/* Update fib according to selection results */
	if (new_fib && old_fib)
		rib_process_update_fib(zvrf, rn, old_fib, new_fib);
	else if (new_fib)
		rib_process_add_fib(zvrf, rn, new_fib);
	else if (old_fib)
		rib_process_del_fib(zvrf, rn, old_fib);

	/* Update SELECTED entry */
	if (old_selected != new_selected || selected_changed) {

		if (new_selected && new_selected != new_fib) {
			nexthop_active_update(rn, new_selected, 1);
			UNSET_FLAG(new_selected->status, ROUTE_ENTRY_CHANGED);
		}

		if (new_selected) {
			SET_FLAG(new_selected->flags, ZEBRA_FLAG_SELECTED);

			/* Special case: new route is system route, so
			 * dataplane update will not be done - ensure we
			 * redistribute the route.
			 */
			if (RIB_SYSTEM_ROUTE(new_selected))
				redistribute_update(p, src_p, new_selected,
						    old_selected);
		}

		if (old_selected) {
			if (!new_selected)
				redistribute_delete(p, src_p, old_selected);
			if (old_selected != new_selected)
				UNSET_FLAG(old_selected->flags,
					   ZEBRA_FLAG_SELECTED);
		}
	}

	/* Remove all RE entries queued for removal */
	RNODE_FOREACH_RE_SAFE (rn, re, next) {
		if (CHECK_FLAG(re->status, ROUTE_ENTRY_REMOVED)) {
			if (IS_ZEBRA_DEBUG_RIB) {
				rnode_debug(rn, vrf_id, "rn %p, removing re %p",
					    (void *)rn, (void *)re);
			}
			rib_unlink(rn, re);
		}
	}

	/*
	 * Check if the dest can be deleted now.
	 */
	rib_gc_dest(rn);
}

/*
 * Utility to match route with dplane context data
 */
static bool rib_route_match_ctx(const struct route_entry *re,
				const struct zebra_dplane_ctx *ctx,
				bool is_update)
{
	bool result = false;

	if (is_update) {
		/*
		 * In 'update' case, we test info about the 'previous' or
		 * 'old' route
		 */
		if ((re->type == dplane_ctx_get_old_type(ctx)) &&
		    (re->instance == dplane_ctx_get_old_instance(ctx))) {
			result = true;

			/* TODO -- we're using this extra test, but it's not
			 * exactly clear why.
			 */
			if (re->type == ZEBRA_ROUTE_STATIC &&
			    (re->distance != dplane_ctx_get_old_distance(ctx) ||
			     re->tag != dplane_ctx_get_old_tag(ctx))) {
				result = false;
			}
		}

	} else {
		/*
		 * Ordinary, single-route case using primary context info
		 */
		if ((dplane_ctx_get_op(ctx) != DPLANE_OP_ROUTE_DELETE) &&
		    CHECK_FLAG(re->status, ROUTE_ENTRY_REMOVED)) {
			/* Skip route that's been deleted */
			goto done;
		}

		if ((re->type == dplane_ctx_get_type(ctx)) &&
		    (re->instance == dplane_ctx_get_instance(ctx))) {
			result = true;

			/* TODO -- we're using this extra test, but it's not
			 * exactly clear why.
			 */
			if (re->type == ZEBRA_ROUTE_STATIC &&
			    (re->distance != dplane_ctx_get_distance(ctx) ||
			     re->tag != dplane_ctx_get_tag(ctx))) {
				result = false;
			}
		}
	}

done:

	return (result);
}

/*
 * Route-update results processing after async dataplane update.
 */
static void rib_process_after(struct zebra_dplane_ctx *ctx)
{
	struct route_table *table = NULL;
	struct zebra_vrf *zvrf = NULL;
	struct route_node *rn = NULL;
	struct route_entry *re = NULL, *old_re = NULL, *rib;
	bool is_update = false;
	struct nexthop *nexthop, *ctx_nexthop;
	char dest_str[PREFIX_STRLEN] = "";
	enum dplane_op_e op;
	enum zebra_dplane_result status;
	const struct prefix *dest_pfx, *src_pfx;

	/* Locate rn and re(s) from ctx */

	table = zebra_vrf_table_with_table_id(dplane_ctx_get_afi(ctx),
					      dplane_ctx_get_safi(ctx),
					      dplane_ctx_get_vrf(ctx),
					      dplane_ctx_get_table(ctx));
	if (table == NULL) {
		if (IS_ZEBRA_DEBUG_DPLANE) {
			zlog_debug("Failed to process dplane results: no table for afi %d, safi %d, vrf %u",
				   dplane_ctx_get_afi(ctx),
				   dplane_ctx_get_safi(ctx),
				   dplane_ctx_get_vrf(ctx));
		}
		goto done;
	}

	zvrf = vrf_info_lookup(dplane_ctx_get_vrf(ctx));

	dest_pfx = dplane_ctx_get_dest(ctx);

	/* Note well: only capturing the prefix string if debug is enabled here;
	 * unconditional log messages will have to generate the string.
	 */
	if (IS_ZEBRA_DEBUG_DPLANE)
		prefix2str(dest_pfx, dest_str, sizeof(dest_str));

	src_pfx = dplane_ctx_get_src(ctx);
	rn = srcdest_rnode_get(table, dplane_ctx_get_dest(ctx),
			       src_pfx ? (struct prefix_ipv6 *)src_pfx : NULL);
	if (rn == NULL) {
		if (IS_ZEBRA_DEBUG_DPLANE) {
			zlog_debug("Failed to process dplane results: no route for %u:%s",
				   dplane_ctx_get_vrf(ctx), dest_str);
		}
		goto done;
	}

	srcdest_rnode_prefixes(rn, &dest_pfx, &src_pfx);

	op = dplane_ctx_get_op(ctx);
	status = dplane_ctx_get_status(ctx);

	if (IS_ZEBRA_DEBUG_DPLANE_DETAIL)
		zlog_debug("%u:%s Processing dplane ctx %p, op %s result %s",
			   dplane_ctx_get_vrf(ctx), dest_str, ctx,
			   dplane_op2str(op), dplane_res2str(status));

	if (op == DPLANE_OP_ROUTE_DELETE) {
		/*
		 * In the delete case, the zebra core datastructs were
		 * updated (or removed) at the time the delete was issued,
		 * so we're just notifying the route owner.
		 */
		if (status == ZEBRA_DPLANE_REQUEST_SUCCESS) {
			zsend_route_notify_owner_ctx(ctx, ZAPI_ROUTE_REMOVED);

			if (zvrf)
				zvrf->removals++;
		} else {
			zsend_route_notify_owner_ctx(ctx,
						     ZAPI_ROUTE_FAIL_INSTALL);

			zlog_warn("%u:%s: Route Deletion failure",
				  dplane_ctx_get_vrf(ctx),
				  prefix2str(dest_pfx,
					     dest_str, sizeof(dest_str)));
		}

		/* Nothing more to do in delete case */
		goto done;
	}

	/*
	 * Update is a bit of a special case, where we may have both old and new
	 * routes to post-process.
	 */
	is_update = dplane_ctx_is_update(ctx);

	/*
	 * Take a pass through the routes, look for matches with the context
	 * info.
	 */
	RNODE_FOREACH_RE(rn, rib) {

		if (re == NULL) {
			if (rib_route_match_ctx(rib, ctx, false))
				re = rib;
		}

		/* Check for old route match */
		if (is_update && (old_re == NULL)) {
			if (rib_route_match_ctx(rib, ctx, true /*is_update*/))
				old_re = rib;
		}

		/* Have we found the routes we need to work on? */
		if (re && ((!is_update || old_re)))
			break;
	}

	/*
	 * Check sequence number(s) to detect stale results before continuing
	 */
	if (re && (re->dplane_sequence != dplane_ctx_get_seq(ctx))) {
		if (IS_ZEBRA_DEBUG_DPLANE_DETAIL) {
			zlog_debug("%u:%s Stale dplane result for re %p",
				   dplane_ctx_get_vrf(ctx), dest_str, re);
		}
		re = NULL;
	}

	if (old_re &&
	    (old_re->dplane_sequence != dplane_ctx_get_old_seq(ctx))) {
		if (IS_ZEBRA_DEBUG_DPLANE_DETAIL) {
			zlog_debug("%u:%s Stale dplane result for old_re %p",
				   dplane_ctx_get_vrf(ctx), dest_str, old_re);
		}
		old_re = NULL;
	}

	/*
	 * Here's sort of a tough one: the route update result is stale.
	 * Is it better to use the context block info to generate
	 * redist and owner notification, or is it better to wait
	 * for the up-to-date result to arrive?
	 */
	if (re == NULL) {
		/* TODO -- for now, only expose up-to-date results */
		goto done;
	}

	if (status == ZEBRA_DPLANE_REQUEST_SUCCESS) {
		/* Update zebra nexthop FIB flag for each
		 * nexthop that was installed.
		 */
		for (ALL_NEXTHOPS_PTR(dplane_ctx_get_ng(ctx), ctx_nexthop)) {

			for (ALL_NEXTHOPS(re->ng, nexthop)) {
				if (nexthop_same(ctx_nexthop, nexthop))
					break;
			}

			if (nexthop == NULL)
				continue;

			if (CHECK_FLAG(nexthop->flags, NEXTHOP_FLAG_RECURSIVE))
				continue;

			if (CHECK_FLAG(ctx_nexthop->flags,
				       NEXTHOP_FLAG_FIB))
				SET_FLAG(nexthop->flags, NEXTHOP_FLAG_FIB);
			else
				UNSET_FLAG(nexthop->flags, NEXTHOP_FLAG_FIB);
		}

		if (zvrf) {
			zvrf->installs++;
			/* Set flag for nexthop tracking processing */
			zvrf->flags |= ZEBRA_VRF_RIB_SCHEDULED;
		}

		/* Redistribute */
		/* TODO -- still calling the redist api using the route_entries,
		 * and there's a corner-case here: if there's no client
		 * for the 'new' route, a redist deleting the 'old' route
		 * will be sent. But if the 'old' context info was stale,
		 * 'old_re' will be NULL here and that delete will not be sent.
		 */
		redistribute_update(dest_pfx, src_pfx, re, old_re);

		/* Notify route owner */
		zsend_route_notify_owner(re,
					 dest_pfx, ZAPI_ROUTE_INSTALLED);

	} else {
		zsend_route_notify_owner(re, dest_pfx,
					 ZAPI_ROUTE_FAIL_INSTALL);

		zlog_warn("%u:%s: Route install failed",
			  dplane_ctx_get_vrf(ctx),
			  prefix2str(dest_pfx,
				     dest_str, sizeof(dest_str)));
	}

done:

	/* Return context to dataplane module */
	dplane_ctx_fini(&ctx);
}

/* Take a list of route_node structs and return 1, if there was a record
 * picked from it and processed by rib_process(). Don't process more,
 * than one RN record; operate only in the specified sub-queue.
 */
static unsigned int process_subq(struct list *subq, uint8_t qindex)
{
	struct listnode *lnode = listhead(subq);
	struct route_node *rnode;
	rib_dest_t *dest;
	struct zebra_vrf *zvrf = NULL;

	if (!lnode)
		return 0;

	rnode = listgetdata(lnode);
	dest = rib_dest_from_rnode(rnode);
	if (dest)
		zvrf = rib_dest_vrf(dest);

	rib_process(rnode);

	if (IS_ZEBRA_DEBUG_RIB_DETAILED) {
		char buf[SRCDEST2STR_BUFFER];
		srcdest_rnode2str(rnode, buf, sizeof(buf));
		zlog_debug("%u:%s: rn %p dequeued from sub-queue %u",
			   zvrf ? zvrf_id(zvrf) : 0, buf, rnode, qindex);
	}

	if (rnode->info)
		UNSET_FLAG(rib_dest_from_rnode(rnode)->flags,
			   RIB_ROUTE_QUEUED(qindex));

#if 0
  else
    {
      zlog_debug ("%s: called for route_node (%p, %d) with no ribs",
                  __func__, rnode, rnode->lock);
      zlog_backtrace(LOG_DEBUG);
    }
#endif
	route_unlock_node(rnode);
	list_delete_node(subq, lnode);
	return 1;
}

/*
 * Perform next-hop tracking processing after RIB updates.
 */
static void do_nht_processing(void)
{
	struct vrf *vrf;
	struct zebra_vrf *zvrf;

	/* Evaluate nexthops for those VRFs which underwent route processing.
	 * This
	 * should limit the evaluation to the necessary VRFs in most common
	 * situations.
	 */
	RB_FOREACH (vrf, vrf_id_head, &vrfs_by_id) {
		zvrf = vrf->info;
		if (zvrf == NULL || !(zvrf->flags & ZEBRA_VRF_RIB_SCHEDULED))
			continue;

		if (IS_ZEBRA_DEBUG_RIB_DETAILED || IS_ZEBRA_DEBUG_NHT)
			zlog_debug("NHT processing check for zvrf %s",
				   zvrf_name(zvrf));

		zvrf->flags &= ~ZEBRA_VRF_RIB_SCHEDULED;
		zebra_evaluate_rnh(zvrf, AF_INET, 0, RNH_NEXTHOP_TYPE, NULL);
		zebra_evaluate_rnh(zvrf, AF_INET, 0, RNH_IMPORT_CHECK_TYPE,
				   NULL);
		zebra_evaluate_rnh(zvrf, AF_INET6, 0, RNH_NEXTHOP_TYPE, NULL);
		zebra_evaluate_rnh(zvrf, AF_INET6, 0, RNH_IMPORT_CHECK_TYPE,
				   NULL);
	}

	/* Schedule LSPs for processing, if needed. */
	zvrf = vrf_info_lookup(VRF_DEFAULT);
	if (mpls_should_lsps_be_processed(zvrf)) {
		if (IS_ZEBRA_DEBUG_MPLS)
			zlog_debug(
				"%u: Scheduling all LSPs upon RIB completion",
				zvrf_id(zvrf));
		zebra_mpls_lsp_schedule(zvrf);
		mpls_unmark_lsps_for_processing(zvrf);
	}
}

/*
 * All meta queues have been processed. Trigger next-hop evaluation.
 */
static void meta_queue_process_complete(struct work_queue *dummy)
{
	do_nht_processing();
}

/* Dispatch the meta queue by picking, processing and unlocking the next RN from
 * a non-empty sub-queue with lowest priority. wq is equal to zebra->ribq and
 * data
 * is pointed to the meta queue structure.
 */
static wq_item_status meta_queue_process(struct work_queue *dummy, void *data)
{
	struct meta_queue *mq = data;
	unsigned i;
	uint32_t queue_len, queue_limit;

	/* Ensure there's room for more dataplane updates */
	queue_limit = dplane_get_in_queue_limit();
	queue_len = dplane_get_in_queue_len();
	if (queue_len > queue_limit) {
		if (IS_ZEBRA_DEBUG_RIB_DETAILED)
			zlog_debug("rib queue: dplane queue len %u, limit %u, retrying",
				   queue_len, queue_limit);

		/* Ensure that the meta-queue is actually enqueued */
		if (work_queue_empty(zebrad.ribq))
			work_queue_add(zebrad.ribq, zebrad.mq);

		return WQ_QUEUE_BLOCKED;
	}

	for (i = 0; i < MQ_SIZE; i++)
		if (process_subq(mq->subq[i], i)) {
			mq->size--;
			break;
		}
	return mq->size ? WQ_REQUEUE : WQ_SUCCESS;
}

/*
 * Map from rib types to queue type (priority) in meta queue
 */
static const uint8_t meta_queue_map[ZEBRA_ROUTE_MAX] = {
	[ZEBRA_ROUTE_SYSTEM] = 4,
	[ZEBRA_ROUTE_KERNEL] = 0,
	[ZEBRA_ROUTE_CONNECT] = 0,
	[ZEBRA_ROUTE_STATIC] = 1,
	[ZEBRA_ROUTE_RIP] = 2,
	[ZEBRA_ROUTE_RIPNG] = 2,
	[ZEBRA_ROUTE_OSPF] = 2,
	[ZEBRA_ROUTE_OSPF6] = 2,
	[ZEBRA_ROUTE_ISIS] = 2,
	[ZEBRA_ROUTE_BGP] = 3,
	[ZEBRA_ROUTE_PIM] = 4, // Shouldn't happen but for safety
	[ZEBRA_ROUTE_EIGRP] = 2,
	[ZEBRA_ROUTE_NHRP] = 2,
	[ZEBRA_ROUTE_HSLS] = 4,
	[ZEBRA_ROUTE_OLSR] = 4,
	[ZEBRA_ROUTE_TABLE] = 1,
	[ZEBRA_ROUTE_LDP] = 4,
	[ZEBRA_ROUTE_VNC] = 3,
	[ZEBRA_ROUTE_VNC_DIRECT] = 3,
	[ZEBRA_ROUTE_VNC_DIRECT_RH] = 3,
	[ZEBRA_ROUTE_BGP_DIRECT] = 3,
	[ZEBRA_ROUTE_BGP_DIRECT_EXT] = 3,
	[ZEBRA_ROUTE_BABEL] = 2,
	[ZEBRA_ROUTE_ALL] = 4, // Shouldn't happen but for safety
};

/* Look into the RN and queue it into one or more priority queues,
 * increasing the size for each data push done.
 */
static void rib_meta_queue_add(struct meta_queue *mq, struct route_node *rn)
{
	struct route_entry *re;

	RNODE_FOREACH_RE (rn, re) {
		uint8_t qindex = meta_queue_map[re->type];
		struct zebra_vrf *zvrf;

		/* Invariant: at this point we always have rn->info set. */
		if (CHECK_FLAG(rib_dest_from_rnode(rn)->flags,
			       RIB_ROUTE_QUEUED(qindex))) {
			if (IS_ZEBRA_DEBUG_RIB_DETAILED)
				rnode_debug(
					rn, re->vrf_id,
					"rn %p is already queued in sub-queue %u",
					(void *)rn, qindex);
			continue;
		}

		SET_FLAG(rib_dest_from_rnode(rn)->flags,
			 RIB_ROUTE_QUEUED(qindex));
		listnode_add(mq->subq[qindex], rn);
		route_lock_node(rn);
		mq->size++;

		if (IS_ZEBRA_DEBUG_RIB_DETAILED)
			rnode_debug(rn, re->vrf_id,
				    "queued rn %p into sub-queue %u",
				    (void *)rn, qindex);

		zvrf = zebra_vrf_lookup_by_id(re->vrf_id);
		if (zvrf)
			zvrf->flags |= ZEBRA_VRF_RIB_SCHEDULED;
	}
}

/* Add route_node to work queue and schedule processing */
void rib_queue_add(struct route_node *rn)
{
	assert(rn);

	/* Pointless to queue a route_node with no RIB entries to add or remove
	 */
	if (!rnode_to_ribs(rn)) {
		zlog_debug("%s: called for route_node (%p, %d) with no ribs",
			   __func__, (void *)rn, rn->lock);
		zlog_backtrace(LOG_DEBUG);
		return;
	}

	if (zebrad.ribq == NULL) {
		flog_err(EC_ZEBRA_WQ_NONEXISTENT,
			 "%s: work_queue does not exist!", __func__);
		return;
	}

	/*
	 * The RIB queue should normally be either empty or holding the only
	 * work_queue_item element. In the latter case this element would
	 * hold a pointer to the meta queue structure, which must be used to
	 * actually queue the route nodes to process. So create the MQ
	 * holder, if necessary, then push the work into it in any case.
	 * This semantics was introduced after 0.99.9 release.
	 */
	if (work_queue_empty(zebrad.ribq))
		work_queue_add(zebrad.ribq, zebrad.mq);

	rib_meta_queue_add(zebrad.mq, rn);

	return;
}

/* Create new meta queue.
   A destructor function doesn't seem to be necessary here.
 */
static struct meta_queue *meta_queue_new(void)
{
	struct meta_queue *new;
	unsigned i;

	new = XCALLOC(MTYPE_WORK_QUEUE, sizeof(struct meta_queue));

	for (i = 0; i < MQ_SIZE; i++) {
		new->subq[i] = list_new();
		assert(new->subq[i]);
	}

	return new;
}

void meta_queue_free(struct meta_queue *mq)
{
	unsigned i;

	for (i = 0; i < MQ_SIZE; i++)
		list_delete(&mq->subq[i]);

	XFREE(MTYPE_WORK_QUEUE, mq);
}

/* initialise zebra rib work queue */
static void rib_queue_init(struct zebra_t *zebra)
{
	assert(zebra);

	if (!(zebra->ribq =
		      work_queue_new(zebra->master, "route_node processing"))) {
		flog_err(EC_ZEBRA_WQ_NONEXISTENT,
			 "%s: could not initialise work queue!", __func__);
		return;
	}

	/* fill in the work queue spec */
	zebra->ribq->spec.workfunc = &meta_queue_process;
	zebra->ribq->spec.errorfunc = NULL;
	zebra->ribq->spec.completion_func = &meta_queue_process_complete;
	/* XXX: TODO: These should be runtime configurable via vty */
	zebra->ribq->spec.max_retries = 3;
	zebra->ribq->spec.hold = ZEBRA_RIB_PROCESS_HOLD_TIME;

	if (!(zebra->mq = meta_queue_new())) {
		flog_err(EC_ZEBRA_WQ_NONEXISTENT,
			 "%s: could not initialise meta queue!", __func__);
		return;
	}
	return;
}

/* RIB updates are processed via a queue of pointers to route_nodes.
 *
 * The queue length is bounded by the maximal size of the routing table,
 * as a route_node will not be requeued, if already queued.
 *
 * REs are submitted via rib_addnode or rib_delnode which set minimal
 * state, or static_install_route (when an existing RE is updated)
 * and then submit route_node to queue for best-path selection later.
 * Order of add/delete state changes are preserved for any given RE.
 *
 * Deleted REs are reaped during best-path selection.
 *
 * rib_addnode
 * |-> rib_link or unset ROUTE_ENTRY_REMOVE      |->Update kernel with
 *       |-------->|                             |  best RE, if required
 *                 |                             |
 * static_install->|->rib_addqueue...... -> rib_process
 *                 |                             |
 *       |-------->|                             |-> rib_unlink
 *       |-> set ROUTE_ENTRY_REMOVE              |
 * rib_delnode                                  (RE freed)
 *
 * The 'info' pointer of a route_node points to a rib_dest_t
 * ('dest'). Queueing state for a route_node is kept on the dest. The
 * dest is created on-demand by rib_link() and is kept around at least
 * as long as there are ribs hanging off it (@see rib_gc_dest()).
 *
 * Refcounting (aka "locking" throughout the GNU Zebra and Quagga code):
 *
 * - route_nodes: refcounted by:
 *   - dest attached to route_node:
 *     - managed by: rib_link/rib_gc_dest
 *   - route_node processing queue
 *     - managed by: rib_addqueue, rib_process.
 *
 */

/* Add RE to head of the route node. */
static void rib_link(struct route_node *rn, struct route_entry *re, int process)
{
	struct route_entry *head;
	rib_dest_t *dest;
	afi_t afi;
	const char *rmap_name;

	assert(re && rn);

	dest = rib_dest_from_rnode(rn);
	if (!dest) {
		if (IS_ZEBRA_DEBUG_RIB_DETAILED)
			rnode_debug(rn, re->vrf_id, "rn %p adding dest", rn);

		dest = XCALLOC(MTYPE_RIB_DEST, sizeof(rib_dest_t));
		route_lock_node(rn); /* rn route table reference */
		rn->info = dest;
		dest->rnode = rn;
	}

	head = dest->routes;
	if (head) {
		head->prev = re;
	}
	re->next = head;
	dest->routes = re;

	afi = (rn->p.family == AF_INET)
		      ? AFI_IP
		      : (rn->p.family == AF_INET6) ? AFI_IP6 : AFI_MAX;
	if (is_zebra_import_table_enabled(afi, re->table)) {
		rmap_name = zebra_get_import_table_route_map(afi, re->table);
		zebra_add_import_table_entry(rn, re, rmap_name);
	} else if (process)
		rib_queue_add(rn);
}

static void rib_addnode(struct route_node *rn,
			struct route_entry *re, int process)
{
	/* RE node has been un-removed before route-node is processed.
	 * route_node must hence already be on the queue for processing..
	 */
	if (CHECK_FLAG(re->status, ROUTE_ENTRY_REMOVED)) {
		if (IS_ZEBRA_DEBUG_RIB)
			rnode_debug(rn, re->vrf_id, "rn %p, un-removed re %p",
				    (void *)rn, (void *)re);

		UNSET_FLAG(re->status, ROUTE_ENTRY_REMOVED);
		return;
	}
	rib_link(rn, re, process);
}

/*
 * rib_unlink
 *
 * Detach a rib structure from a route_node.
 *
 * Note that a call to rib_unlink() should be followed by a call to
 * rib_gc_dest() at some point. This allows a rib_dest_t that is no
 * longer required to be deleted.
 */
void rib_unlink(struct route_node *rn, struct route_entry *re)
{
	rib_dest_t *dest;

	assert(rn && re);

	if (IS_ZEBRA_DEBUG_RIB)
		rnode_debug(rn, re->vrf_id, "rn %p, re %p", (void *)rn,
			    (void *)re);

	dest = rib_dest_from_rnode(rn);

	if (re->next)
		re->next->prev = re->prev;

	if (re->prev)
		re->prev->next = re->next;
	else {
		dest->routes = re->next;
	}

	if (dest->selected_fib == re)
		dest->selected_fib = NULL;

	nexthops_free(re->ng.nexthop);
	XFREE(MTYPE_RE, re);
}

void rib_delnode(struct route_node *rn, struct route_entry *re)
{
	afi_t afi;

	if (IS_ZEBRA_DEBUG_RIB)
		rnode_debug(rn, re->vrf_id, "rn %p, re %p, removing",
			    (void *)rn, (void *)re);
	SET_FLAG(re->status, ROUTE_ENTRY_REMOVED);

	afi = (rn->p.family == AF_INET)
		      ? AFI_IP
		      : (rn->p.family == AF_INET6) ? AFI_IP6 : AFI_MAX;
	if (is_zebra_import_table_enabled(afi, re->table)) {
		zebra_del_import_table_entry(rn, re);
		/* Just clean up if non main table */
		if (IS_ZEBRA_DEBUG_RIB) {
			char buf[SRCDEST2STR_BUFFER];
			srcdest_rnode2str(rn, buf, sizeof(buf));
			zlog_debug(
				"%u:%s: Freeing route rn %p, re %p (type %d)",
				re->vrf_id, buf, rn, re, re->type);
		}

		rib_unlink(rn, re);
	} else {
		rib_queue_add(rn);
	}
}

/* This function dumps the contents of a given RE entry into
 * standard debug log. Calling function name and IP prefix in
 * question are passed as 1st and 2nd arguments.
 */

void _route_entry_dump(const char *func, union prefixconstptr pp,
		       union prefixconstptr src_pp,
		       const struct route_entry *re)
{
	const struct prefix *src_p = src_pp.p;
	bool is_srcdst = src_p && src_p->prefixlen;
	char straddr[PREFIX_STRLEN];
	char srcaddr[PREFIX_STRLEN];
	struct nexthop *nexthop;

	zlog_debug("%s: dumping RE entry %p for %s%s%s vrf %u", func,
		   (const void *)re, prefix2str(pp, straddr, sizeof(straddr)),
		   is_srcdst ? " from " : "",
		   is_srcdst ? prefix2str(src_pp, srcaddr, sizeof(srcaddr))
			     : "",
		   re->vrf_id);
	zlog_debug("%s: uptime == %lu, type == %u, instance == %d, table == %d",
		   func, (unsigned long)re->uptime, re->type, re->instance,
		   re->table);
	zlog_debug(
		"%s: metric == %u, mtu == %u, distance == %u, flags == %u, status == %u",
		func, re->metric, re->mtu, re->distance, re->flags, re->status);
	zlog_debug("%s: nexthop_num == %u, nexthop_active_num == %u", func,
		   re->nexthop_num, re->nexthop_active_num);

	for (ALL_NEXTHOPS(re->ng, nexthop)) {
		struct interface *ifp;
		struct vrf *vrf = vrf_lookup_by_id(nexthop->vrf_id);

		switch (nexthop->type) {
		case NEXTHOP_TYPE_BLACKHOLE:
			sprintf(straddr, "Blackhole");
			break;
		case NEXTHOP_TYPE_IFINDEX:
			ifp = if_lookup_by_index(nexthop->ifindex,
						 nexthop->vrf_id);
			sprintf(straddr, "%s", ifp ? ifp->name : "Unknown");
			break;
		case NEXTHOP_TYPE_IPV4:
			/* fallthrough */
		case NEXTHOP_TYPE_IPV4_IFINDEX:
			inet_ntop(AF_INET, &nexthop->gate, straddr,
				  INET6_ADDRSTRLEN);
			break;
		case NEXTHOP_TYPE_IPV6:
		case NEXTHOP_TYPE_IPV6_IFINDEX:
			inet_ntop(AF_INET6, &nexthop->gate, straddr,
				  INET6_ADDRSTRLEN);
			break;
		}
		zlog_debug("%s: %s %s[%u] vrf %s(%u) with flags %s%s%s", func,
			   (nexthop->rparent ? "  NH" : "NH"), straddr,
			   nexthop->ifindex, vrf ? vrf->name : "Unknown",
			   nexthop->vrf_id,
			   (CHECK_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE)
				    ? "ACTIVE "
				    : ""),
			   (CHECK_FLAG(nexthop->flags, NEXTHOP_FLAG_FIB)
				    ? "FIB "
				    : ""),
			   (CHECK_FLAG(nexthop->flags, NEXTHOP_FLAG_RECURSIVE)
				    ? "RECURSIVE"
				    : ""));
	}
	zlog_debug("%s: dump complete", func);
}

/* This is an exported helper to rtm_read() to dump the strange
 * RE entry found by rib_lookup_ipv4_route()
 */

void rib_lookup_and_dump(struct prefix_ipv4 *p, vrf_id_t vrf_id)
{
	struct route_table *table;
	struct route_node *rn;
	struct route_entry *re;
	char prefix_buf[INET_ADDRSTRLEN];

	/* Lookup table.  */
	table = zebra_vrf_table(AFI_IP, SAFI_UNICAST, vrf_id);
	if (!table) {
		flog_err(EC_ZEBRA_TABLE_LOOKUP_FAILED,
			 "%s:%u zebra_vrf_table() returned NULL", __func__,
			 vrf_id);
		return;
	}

	/* Scan the RIB table for exactly matching RE entry. */
	rn = route_node_lookup(table, (struct prefix *)p);

	/* No route for this prefix. */
	if (!rn) {
		zlog_debug("%s:%u lookup failed for %s", __func__, vrf_id,
			   prefix2str((struct prefix *)p, prefix_buf,
				      sizeof(prefix_buf)));
		return;
	}

	/* Unlock node. */
	route_unlock_node(rn);

	/* let's go */
	RNODE_FOREACH_RE (rn, re) {
		zlog_debug("%s:%u rn %p, re %p: %s, %s",
			   __func__, vrf_id,
			   (void *)rn, (void *)re,
			   (CHECK_FLAG(re->status, ROUTE_ENTRY_REMOVED)
				    ? "removed"
				    : "NOT removed"),
			   (CHECK_FLAG(re->flags, ZEBRA_FLAG_SELECTED)
				    ? "selected"
				    : "NOT selected"));
		route_entry_dump(p, NULL, re);
	}
}

/* Check if requested address assignment will fail due to another
 * route being installed by zebra in FIB already. Take necessary
 * actions, if needed: remove such a route from FIB and deSELECT
 * corresponding RE entry. Then put affected RN into RIBQ head.
 */
void rib_lookup_and_pushup(struct prefix_ipv4 *p, vrf_id_t vrf_id)
{
	struct route_table *table;
	struct route_node *rn;
	unsigned changed = 0;
	rib_dest_t *dest;

	if (NULL == (table = zebra_vrf_table(AFI_IP, SAFI_UNICAST, vrf_id))) {
		flog_err(EC_ZEBRA_TABLE_LOOKUP_FAILED,
			 "%s:%u zebra_vrf_table() returned NULL", __func__,
			 vrf_id);
		return;
	}

	/* No matches would be the simplest case. */
	if (NULL == (rn = route_node_lookup(table, (struct prefix *)p)))
		return;

	/* Unlock node. */
	route_unlock_node(rn);

	dest = rib_dest_from_rnode(rn);
	/* Check all RE entries. In case any changes have to be done, requeue
	 * the RN into RIBQ head. If the routing message about the new connected
	 * route (generated by the IP address we are going to assign very soon)
	 * comes before the RIBQ is processed, the new RE entry will join
	 * RIBQ record already on head. This is necessary for proper
	 * revalidation
	 * of the rest of the RE.
	 */
	if (dest->selected_fib && !RIB_SYSTEM_ROUTE(dest->selected_fib)) {
		changed = 1;
		if (IS_ZEBRA_DEBUG_RIB) {
			char buf[PREFIX_STRLEN];

			zlog_debug("%u:%s: freeing way for connected prefix",
				   dest->selected_fib->vrf_id,
				   prefix2str(&rn->p, buf, sizeof(buf)));
			route_entry_dump(&rn->p, NULL, dest->selected_fib);
		}
		rib_uninstall(rn, dest->selected_fib);
	}
	if (changed)
		rib_queue_add(rn);
}

int rib_add_multipath(afi_t afi, safi_t safi, struct prefix *p,
		      struct prefix_ipv6 *src_p, struct route_entry *re)
{
	struct route_table *table;
	struct route_node *rn;
	struct route_entry *same = NULL;
	struct nexthop *nexthop;
	int ret = 0;

	if (!re)
		return 0;

	assert(!src_p || !src_p->prefixlen || afi == AFI_IP6);

	/* Lookup table.  */
	table = zebra_vrf_table_with_table_id(afi, safi, re->vrf_id, re->table);
	if (!table) {
		XFREE(MTYPE_RE, re);
		return 0;
	}

	/* Make it sure prefixlen is applied to the prefix. */
	apply_mask(p);
	if (src_p)
		apply_mask_ipv6(src_p);

	/* Set default distance by route type. */
	if (re->distance == 0) {
		re->distance = route_distance(re->type);

		/* iBGP distance is 200. */
		if (re->type == ZEBRA_ROUTE_BGP
		    && CHECK_FLAG(re->flags, ZEBRA_FLAG_IBGP))
			re->distance = 200;
	}

	/* Lookup route node.*/
	rn = srcdest_rnode_get(table, p, src_p);

	/*
	 * If same type of route are installed, treat it as a implicit
	 * withdraw.
	 * If the user has specified the No route replace semantics
	 * for the install don't do a route replace.
	 */
	RNODE_FOREACH_RE (rn, same) {
		if (CHECK_FLAG(same->status, ROUTE_ENTRY_REMOVED))
			continue;

		if (same->type != re->type)
			continue;
		if (same->instance != re->instance)
			continue;
		if (same->type == ZEBRA_ROUTE_KERNEL
		    && same->metric != re->metric)
			continue;

		if (CHECK_FLAG(re->flags, ZEBRA_FLAG_RR_USE_DISTANCE) &&
		    same->distance != re->distance)
			continue;

		/*
		 * We should allow duplicate connected routes
		 * because of IPv6 link-local routes and unnumbered
		 * interfaces on Linux.
		 */
		if (same->type != ZEBRA_ROUTE_CONNECT)
			break;
	}

	/* If this route is kernel route, set FIB flag to the route. */
	if (RIB_SYSTEM_ROUTE(re))
		for (nexthop = re->ng.nexthop; nexthop; nexthop = nexthop->next)
			SET_FLAG(nexthop->flags, NEXTHOP_FLAG_FIB);

	/* Link new re to node.*/
	if (IS_ZEBRA_DEBUG_RIB) {
		rnode_debug(
			rn, re->vrf_id,
			"Inserting route rn %p, re %p (type %d) existing %p",
			(void *)rn, (void *)re, re->type, (void *)same);

		if (IS_ZEBRA_DEBUG_RIB_DETAILED)
			route_entry_dump(p, src_p, re);
	}
	rib_addnode(rn, re, 1);
	ret = 1;

	/* Free implicit route.*/
	if (same) {
		rib_delnode(rn, same);
		ret = -1;
	}

	route_unlock_node(rn);
	return ret;
}

void rib_delete(afi_t afi, safi_t safi, vrf_id_t vrf_id, int type,
		unsigned short instance, int flags, struct prefix *p,
		struct prefix_ipv6 *src_p, const struct nexthop *nh,
		uint32_t table_id, uint32_t metric, uint8_t distance,
		bool fromkernel)
{
	struct route_table *table;
	struct route_node *rn;
	struct route_entry *re;
	struct route_entry *fib = NULL;
	struct route_entry *same = NULL;
	struct nexthop *rtnh;
	char buf2[INET6_ADDRSTRLEN];
	rib_dest_t *dest;

	assert(!src_p || !src_p->prefixlen || afi == AFI_IP6);

	/* Lookup table.  */
	table = zebra_vrf_table_with_table_id(afi, safi, vrf_id, table_id);
	if (!table)
		return;

	/* Apply mask. */
	apply_mask(p);
	if (src_p)
		apply_mask_ipv6(src_p);

	/* Lookup route node. */
	rn = srcdest_rnode_lookup(table, p, src_p);
	if (!rn) {
		char dst_buf[PREFIX_STRLEN], src_buf[PREFIX_STRLEN];

		prefix2str(p, dst_buf, sizeof(dst_buf));
		if (src_p && src_p->prefixlen)
			prefix2str(src_p, src_buf, sizeof(src_buf));
		else
			src_buf[0] = '\0';

		if (IS_ZEBRA_DEBUG_RIB)
			zlog_debug("%u:%s%s%s doesn't exist in rib", vrf_id,
				   dst_buf,
				   (src_buf[0] != '\0') ? " from " : "",
				   src_buf);
		return;
	}

	dest = rib_dest_from_rnode(rn);
	fib = dest->selected_fib;

	/* Lookup same type route. */
	RNODE_FOREACH_RE (rn, re) {
		if (CHECK_FLAG(re->status, ROUTE_ENTRY_REMOVED))
			continue;

		if (re->type != type)
			continue;
		if (re->instance != instance)
			continue;
		if (CHECK_FLAG(re->flags, ZEBRA_FLAG_RR_USE_DISTANCE) &&
		    distance != re->distance)
			continue;

		if (re->type == ZEBRA_ROUTE_KERNEL && re->metric != metric)
			continue;
		if (re->type == ZEBRA_ROUTE_CONNECT && (rtnh = re->ng.nexthop)
		    && rtnh->type == NEXTHOP_TYPE_IFINDEX && nh) {
			if (rtnh->ifindex != nh->ifindex)
				continue;
			same = re;
			break;
		}
		/* Make sure that the route found has the same gateway. */
		else {
			if (nh == NULL) {
				same = re;
				break;
			}
			for (ALL_NEXTHOPS(re->ng, rtnh))
				if (nexthop_same_no_recurse(rtnh, nh)) {
					same = re;
					break;
				}
			if (same)
				break;
		}
	}
	/* If same type of route can't be found and this message is from
	   kernel. */
	if (!same) {
		/*
		 * In the past(HA!) we could get here because
		 * we were receiving a route delete from the
		 * kernel and we're not marking the proto
		 * as coming from it's appropriate originator.
		 * Now that we are properly noticing the fact
		 * that the kernel has deleted our route we
		 * are not going to get called in this path
		 * I am going to leave this here because
		 * this might still work this way on non-linux
		 * platforms as well as some weird state I have
		 * not properly thought of yet.
		 * If we can show that this code path is
		 * dead then we can remove it.
		 */
		if (fib && CHECK_FLAG(flags, ZEBRA_FLAG_SELFROUTE)) {
			if (IS_ZEBRA_DEBUG_RIB) {
				rnode_debug(
					rn, vrf_id,
					"rn %p, re %p (type %d) was deleted from kernel, adding",
					rn, fib, fib->type);
			}
			if (allow_delete) {
				/* Unset flags. */
				for (rtnh = fib->ng.nexthop; rtnh;
				     rtnh = rtnh->next)
					UNSET_FLAG(rtnh->flags,
						   NEXTHOP_FLAG_FIB);

				/*
				 * This is a non FRR route
				 * as such we should mark
				 * it as deleted
				 */
				dest->selected_fib = NULL;
			} else {
				/* This means someone else, other than Zebra,
				 * has deleted
				 * a Zebra router from the kernel. We will add
				 * it back */
				rib_install_kernel(rn, fib, NULL);
			}
		} else {
			if (IS_ZEBRA_DEBUG_RIB) {
				if (nh)
					rnode_debug(
						rn, vrf_id,
						"via %s ifindex %d type %d "
						"doesn't exist in rib",
						inet_ntop(afi2family(afi),
							  &nh->gate, buf2,
							  sizeof(buf2)),
							  nh->ifindex, type);
				else
					rnode_debug(
						rn, vrf_id,
						"type %d doesn't exist in rib",
						type);
			}
			route_unlock_node(rn);
			return;
		}
	}

	if (same) {
		if (fromkernel && CHECK_FLAG(flags, ZEBRA_FLAG_SELFROUTE)
		    && !allow_delete) {
			rib_install_kernel(rn, same, NULL);
			route_unlock_node(rn);

			return;
		}

		if (CHECK_FLAG(flags, ZEBRA_FLAG_EVPN_ROUTE)) {
			struct nexthop *tmp_nh;

			for (ALL_NEXTHOPS(re->ng, tmp_nh)) {
				struct ipaddr vtep_ip;

				memset(&vtep_ip, 0, sizeof(struct ipaddr));
				if (afi == AFI_IP) {
					vtep_ip.ipa_type = IPADDR_V4;
					memcpy(&(vtep_ip.ipaddr_v4),
					       &(tmp_nh->gate.ipv4),
					       sizeof(struct in_addr));
				} else {
					vtep_ip.ipa_type = IPADDR_V6;
					memcpy(&(vtep_ip.ipaddr_v6),
					       &(tmp_nh->gate.ipv6),
					       sizeof(struct in6_addr));
				}
				zebra_vxlan_evpn_vrf_route_del(re->vrf_id,
							       &vtep_ip, p);
			}
		}
		rib_delnode(rn, same);
	}

	route_unlock_node(rn);
	return;
}


int rib_add(afi_t afi, safi_t safi, vrf_id_t vrf_id, int type,
	    unsigned short instance, int flags, struct prefix *p,
	    struct prefix_ipv6 *src_p, const struct nexthop *nh,
	    uint32_t table_id, uint32_t metric, uint32_t mtu, uint8_t distance,
	    route_tag_t tag)
{
	struct route_entry *re;
	struct nexthop *nexthop;

	/* Allocate new route_entry structure. */
	re = XCALLOC(MTYPE_RE, sizeof(struct route_entry));
	re->type = type;
	re->instance = instance;
	re->distance = distance;
	re->flags = flags;
	re->metric = metric;
	re->mtu = mtu;
	re->table = table_id;
	re->vrf_id = vrf_id;
	re->nexthop_num = 0;
	re->uptime = time(NULL);
	re->tag = tag;

	/* Add nexthop. */
	nexthop = nexthop_new();
	*nexthop = *nh;
	route_entry_nexthop_add(re, nexthop);

	return rib_add_multipath(afi, safi, p, src_p, re);
}

/* Schedule routes of a particular table (address-family) based on event. */
void rib_update_table(struct route_table *table, rib_update_event_t event)
{
	struct route_node *rn;
	struct route_entry *re, *next;

	/* Walk all routes and queue for processing, if appropriate for
	 * the trigger event.
	 */
	for (rn = route_top(table); rn; rn = srcdest_route_next(rn)) {
		/*
		 * If we are looking at a route node and the node
		 * has already been queued  we don't
		 * need to queue it up again
		 */
		if (rn->info && CHECK_FLAG(rib_dest_from_rnode(rn)->flags,
					   RIB_ROUTE_ANY_QUEUED))
			continue;
		switch (event) {
		case RIB_UPDATE_IF_CHANGE:
			/* Examine all routes that won't get processed by the
			 * protocol or
			 * triggered by nexthop evaluation (NHT). This would be
			 * system,
			 * kernel and certain static routes. Note that NHT will
			 * get
			 * triggered upon an interface event as connected routes
			 * always
			 * get queued for processing.
			 */
			RNODE_FOREACH_RE_SAFE (rn, re, next) {
				struct nexthop *nh;

				if (re->type != ZEBRA_ROUTE_SYSTEM
				    && re->type != ZEBRA_ROUTE_KERNEL
				    && re->type != ZEBRA_ROUTE_CONNECT
				    && re->type != ZEBRA_ROUTE_STATIC)
					continue;

				if (re->type != ZEBRA_ROUTE_STATIC) {
					rib_queue_add(rn);
					continue;
				}

				for (nh = re->ng.nexthop; nh; nh = nh->next)
					if (!(nh->type == NEXTHOP_TYPE_IPV4
					      || nh->type == NEXTHOP_TYPE_IPV6))
						break;

				/* If we only have nexthops to a
				 * gateway, NHT will
				 * take care.
				 */
				if (nh)
					rib_queue_add(rn);
			}
			break;

		case RIB_UPDATE_RMAP_CHANGE:
		case RIB_UPDATE_OTHER:
			/* Right now, examine all routes. Can restrict to a
			 * protocol in
			 * some cases (TODO).
			 */
			if (rnode_to_ribs(rn))
				rib_queue_add(rn);
			break;

		default:
			break;
		}
	}
}

/* RIB update function. */
void rib_update(vrf_id_t vrf_id, rib_update_event_t event)
{
	struct route_table *table;

	/* Process routes of interested address-families. */
	table = zebra_vrf_table(AFI_IP, SAFI_UNICAST, vrf_id);
	if (table) {
		if (IS_ZEBRA_DEBUG_EVENT)
			zlog_debug("%s : AFI_IP event %d", __func__, event);
		rib_update_table(table, event);
	}

	table = zebra_vrf_table(AFI_IP6, SAFI_UNICAST, vrf_id);
	if (table) {
		if (IS_ZEBRA_DEBUG_EVENT)
			zlog_debug("%s : AFI_IP6 event %d", __func__, event);
		rib_update_table(table, event);
	}
}

/* Delete self installed routes after zebra is relaunched.  */
void rib_sweep_table(struct route_table *table)
{
	struct route_node *rn;
	struct route_entry *re;
	struct route_entry *next;
	struct nexthop *nexthop;

	if (!table)
		return;

	for (rn = route_top(table); rn; rn = srcdest_route_next(rn)) {
		RNODE_FOREACH_RE_SAFE (rn, re, next) {
			if (IS_ZEBRA_DEBUG_RIB)
				route_entry_dump(&rn->p, NULL, re);

			if (CHECK_FLAG(re->status, ROUTE_ENTRY_REMOVED))
				continue;

			if (!CHECK_FLAG(re->flags, ZEBRA_FLAG_SELFROUTE))
				continue;

			/*
			 * So we are starting up and have received
			 * routes from the kernel that we have installed
			 * from a previous run of zebra but not cleaned
			 * up ( say a kill -9 )
			 * But since we haven't actually installed
			 * them yet( we received them from the kernel )
			 * we don't think they are active.
			 * So let's pretend they are active to actually
			 * remove them.
			 * In all honesty I'm not sure if we should
			 * mark them as active when we receive them
			 * This is startup only so probably ok.
			 *
			 * If we ever decide to move rib_sweep_table
			 * to a different spot (ie startup )
			 * this decision needs to be revisited
			 */
			for (ALL_NEXTHOPS(re->ng, nexthop))
				SET_FLAG(nexthop->flags, NEXTHOP_FLAG_FIB);

			rib_uninstall_kernel(rn, re);
			rib_delnode(rn, re);
		}
	}
}

/* Sweep all RIB tables.  */
void rib_sweep_route(void)
{
	struct vrf *vrf;
	struct zebra_vrf *zvrf;

	RB_FOREACH (vrf, vrf_id_head, &vrfs_by_id) {
		if ((zvrf = vrf->info) == NULL)
			continue;

		rib_sweep_table(zvrf->table[AFI_IP][SAFI_UNICAST]);
		rib_sweep_table(zvrf->table[AFI_IP6][SAFI_UNICAST]);
	}

	zebra_router_sweep_route();
}

/* Remove specific by protocol routes from 'table'. */
unsigned long rib_score_proto_table(uint8_t proto, unsigned short instance,
				    struct route_table *table)
{
	struct route_node *rn;
	struct route_entry *re;
	struct route_entry *next;
	unsigned long n = 0;

	if (table)
		for (rn = route_top(table); rn; rn = srcdest_route_next(rn))
			RNODE_FOREACH_RE_SAFE (rn, re, next) {
				if (CHECK_FLAG(re->status, ROUTE_ENTRY_REMOVED))
					continue;
				if (re->type == proto
				    && re->instance == instance) {
					rib_delnode(rn, re);
					n++;
				}
			}
	return n;
}

/* Remove specific by protocol routes. */
unsigned long rib_score_proto(uint8_t proto, unsigned short instance)
{
	struct vrf *vrf;
	struct zebra_vrf *zvrf;
	unsigned long cnt = 0;

	RB_FOREACH (vrf, vrf_id_head, &vrfs_by_id)
		if ((zvrf = vrf->info) != NULL)
			cnt += rib_score_proto_table(
				       proto, instance,
				       zvrf->table[AFI_IP][SAFI_UNICAST])
			       + rib_score_proto_table(
					 proto, instance,
					 zvrf->table[AFI_IP6][SAFI_UNICAST]);

	cnt += zebra_router_score_proto(proto, instance);

	return cnt;
}

/* Close RIB and clean up kernel routes. */
void rib_close_table(struct route_table *table)
{
	struct route_node *rn;
	rib_table_info_t *info;
	rib_dest_t *dest;

	if (!table)
		return;

	info = route_table_get_info(table);

	for (rn = route_top(table); rn; rn = srcdest_route_next(rn)) {
		dest = rib_dest_from_rnode(rn);

		if (dest && dest->selected_fib) {
			if (info->safi == SAFI_UNICAST)
				hook_call(rib_update, rn, NULL);

			if (!RIB_SYSTEM_ROUTE(dest->selected_fib)) {
				rib_uninstall_kernel(rn, dest->selected_fib);
				dest->selected_fib = NULL;
			}
		}
	}
}

/*
 *
 */
static int rib_process_dplane_results(struct thread *thread)
{
	struct zebra_dplane_ctx *ctx;

	do {
		/* Take lock controlling queue of results */
		pthread_mutex_lock(&dplane_mutex);
		{
			/* Dequeue context block */
			ctx = dplane_ctx_dequeue(&rib_dplane_q);
		}
		pthread_mutex_unlock(&dplane_mutex);

		if (ctx)
			rib_process_after(ctx);
		else
			break;

	} while (1);

	/* Check for nexthop tracking processing after finishing with results */
	do_nht_processing();

	return 0;
}

/*
 * Results are returned from the dataplane subsystem, in the context of
 * the dataplane pthread. We enqueue the results here for processing by
 * the main thread later.
 */
static int rib_dplane_results(struct zebra_dplane_ctx *ctx)
{
	/* Take lock controlling queue of results */
	pthread_mutex_lock(&dplane_mutex);
	{
		/* Enqueue context block */
		dplane_ctx_enqueue_tail(&rib_dplane_q, ctx);
	}
	pthread_mutex_unlock(&dplane_mutex);

	/* Ensure event is signalled to zebra main thread */
	thread_add_event(zebrad.master, rib_process_dplane_results, NULL, 0,
			 &t_dplane);

	return 0;
}

/* Routing information base initialize. */
void rib_init(void)
{
	rib_queue_init(&zebrad);

	/* Init dataplane, and register for results */
	pthread_mutex_init(&dplane_mutex, NULL);
	TAILQ_INIT(&rib_dplane_q);
	zebra_dplane_init();
	dplane_results_register(rib_dplane_results);
}

/*
 * vrf_id_get_next
 *
 * Get the first vrf id that is greater than the given vrf id if any.
 *
 * Returns TRUE if a vrf id was found, FALSE otherwise.
 */
static inline int vrf_id_get_next(vrf_id_t vrf_id, vrf_id_t *next_id_p)
{
	struct vrf *vrf;

	vrf = vrf_lookup_by_id(vrf_id);
	if (vrf) {
		vrf = RB_NEXT(vrf_id_head, vrf);
		if (vrf) {
			*next_id_p = vrf->vrf_id;
			return 1;
		}
	}

	return 0;
}

/*
 * rib_tables_iter_next
 *
 * Returns the next table in the iteration.
 */
struct route_table *rib_tables_iter_next(rib_tables_iter_t *iter)
{
	struct route_table *table;

	/*
	 * Array that helps us go over all AFI/SAFI combinations via one
	 * index.
	 */
	static struct {
		afi_t afi;
		safi_t safi;
	} afi_safis[] = {
		{AFI_IP, SAFI_UNICAST},		{AFI_IP, SAFI_MULTICAST},
		{AFI_IP, SAFI_LABELED_UNICAST}, {AFI_IP6, SAFI_UNICAST},
		{AFI_IP6, SAFI_MULTICAST},      {AFI_IP6, SAFI_LABELED_UNICAST},
	};

	table = NULL;

	switch (iter->state) {

	case RIB_TABLES_ITER_S_INIT:
		iter->vrf_id = VRF_DEFAULT;
		iter->afi_safi_ix = -1;

	/* Fall through */

	case RIB_TABLES_ITER_S_ITERATING:
		iter->afi_safi_ix++;
		while (1) {

			while (iter->afi_safi_ix
			       < (int)ZEBRA_NUM_OF(afi_safis)) {
				table = zebra_vrf_table(
					afi_safis[iter->afi_safi_ix].afi,
					afi_safis[iter->afi_safi_ix].safi,
					iter->vrf_id);
				if (table)
					break;

				iter->afi_safi_ix++;
			}

			/*
			 * Found another table in this vrf.
			 */
			if (table)
				break;

			/*
			 * Done with all tables in the current vrf, go to the
			 * next
			 * one.
			 */
			if (!vrf_id_get_next(iter->vrf_id, &iter->vrf_id))
				break;

			iter->afi_safi_ix = 0;
		}

		break;

	case RIB_TABLES_ITER_S_DONE:
		return NULL;
	}

	if (table)
		iter->state = RIB_TABLES_ITER_S_ITERATING;
	else
		iter->state = RIB_TABLES_ITER_S_DONE;

	return table;
}