Merge pull request #10838 from ton31337/feature/bgpd_callbacks_for_start_end_configur...

[mirror_frr.git] / bgpd / bgp_evpn_mh.c

/* EVPN Multihoming procedures
 *
 * Copyright (C) 2019 Cumulus Networks, Inc.
 * Anuradha Karuppiah
 *
 * This file is part of FRR.
 *
 * FRRouting 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.
 *
 * FRRouting 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.
 *
 */

#include <zebra.h>

#include "command.h"
#include "filter.h"
#include "prefix.h"
#include "log.h"
#include "memory.h"
#include "stream.h"
#include "hash.h"
#include "jhash.h"
#include "zclient.h"

#include "lib/printfrr.h"

#include "bgpd/bgp_attr_evpn.h"
#include "bgpd/bgpd.h"
#include "bgpd/bgp_table.h"
#include "bgpd/bgp_route.h"
#include "bgpd/bgp_attr.h"
#include "bgpd/bgp_mplsvpn.h"
#include "bgpd/bgp_evpn.h"
#include "bgpd/bgp_evpn_private.h"
#include "bgpd/bgp_evpn_mh.h"
#include "bgpd/bgp_ecommunity.h"
#include "bgpd/bgp_encap_types.h"
#include "bgpd/bgp_debug.h"
#include "bgpd/bgp_errors.h"
#include "bgpd/bgp_aspath.h"
#include "bgpd/bgp_zebra.h"
#include "bgpd/bgp_addpath.h"
#include "bgpd/bgp_label.h"
#include "bgpd/bgp_nht.h"
#include "bgpd/bgp_mpath.h"
#include "bgpd/bgp_trace.h"

static void bgp_evpn_local_es_down(struct bgp *bgp,
                struct bgp_evpn_es *es);
static void bgp_evpn_local_type1_evi_route_del(struct bgp *bgp,
                struct bgp_evpn_es *es);
static struct bgp_evpn_es_vtep *bgp_evpn_es_vtep_add(struct bgp *bgp,
                                                     struct bgp_evpn_es *es,
                                                     struct in_addr vtep_ip,
                                                     bool esr, uint8_t df_alg,
                                                     uint16_t df_pref);
static void bgp_evpn_es_vtep_del(struct bgp *bgp,
                struct bgp_evpn_es *es, struct in_addr vtep_ip, bool esr);
static void bgp_evpn_es_cons_checks_pend_add(struct bgp_evpn_es *es);
static void bgp_evpn_es_cons_checks_pend_del(struct bgp_evpn_es *es);
static struct bgp_evpn_es_evi *
bgp_evpn_local_es_evi_do_del(struct bgp_evpn_es_evi *es_evi);
static uint32_t bgp_evpn_es_get_active_vtep_cnt(struct bgp_evpn_es *es);
static void bgp_evpn_l3nhg_update_on_vtep_chg(struct bgp_evpn_es *es);
static struct bgp_evpn_es *bgp_evpn_es_new(struct bgp *bgp, const esi_t *esi);
static void bgp_evpn_es_free(struct bgp_evpn_es *es, const char *caller);
static void bgp_evpn_path_es_unlink(struct bgp_path_es_info *es_info);
static void bgp_evpn_mac_update_on_es_local_chg(struct bgp_evpn_es *es,
                                                bool is_local);

esi_t zero_esi_buf, *zero_esi = &zero_esi_buf;
static void bgp_evpn_run_consistency_checks(struct thread *t);
static void bgp_evpn_path_nh_info_free(struct bgp_path_evpn_nh_info *nh_info);
static void bgp_evpn_path_nh_unlink(struct bgp_path_evpn_nh_info *nh_info);

/******************************************************************************
 * per-ES (Ethernet Segment) routing table
 *
 * Following routes are added to the ES's routing table -
 * 1. Local and remote ESR (Type-4)
 * 2. Local EAD-per-ES (Type-1).
 *
 * Key for these routes is {ESI, VTEP-IP} so the path selection is practically
 * a no-op i.e. all paths lead to same VTEP-IP (i.e. result in the same VTEP
 * being added to same ES).
 *
 * Note the following routes go into the VNI routing table (instead of the
 * ES routing table) -
 * 1. Remote EAD-per-ES
 * 2. Local and remote EAD-per-EVI
 */

/* Calculate the best path for a multi-homing (Type-1 or Type-4) route
 * installed in the ES's routing table.
 */
static int bgp_evpn_es_route_select_install(struct bgp *bgp,
                                            struct bgp_evpn_es *es,
                                            struct bgp_dest *dest)
{
        int ret = 0;
        afi_t afi = AFI_L2VPN;
        safi_t safi = SAFI_EVPN;
        struct bgp_path_info *old_select; /* old best */
        struct bgp_path_info *new_select; /* new best */
        struct bgp_path_info_pair old_and_new;

        /* Compute the best path. */
        bgp_best_selection(bgp, dest, &bgp->maxpaths[afi][safi], &old_and_new,
                           afi, safi);
        old_select = old_and_new.old;
        new_select = old_and_new.new;

        /*
         * If the best path hasn't changed - see if something needs to be
         * updated
         */
        if (old_select && old_select == new_select
            && old_select->type == ZEBRA_ROUTE_BGP
            && old_select->sub_type == BGP_ROUTE_IMPORTED
            && !CHECK_FLAG(dest->flags, BGP_NODE_USER_CLEAR)
            && !CHECK_FLAG(old_select->flags, BGP_PATH_ATTR_CHANGED)
            && !bgp_addpath_is_addpath_used(&bgp->tx_addpath, afi, safi)) {
                if (bgp_zebra_has_route_changed(old_select)) {
                        bgp_evpn_es_vtep_add(bgp, es, old_select->attr->nexthop,
                                             true /*esr*/,
                                             old_select->attr->df_alg,
                                             old_select->attr->df_pref);
                }
                UNSET_FLAG(old_select->flags, BGP_PATH_MULTIPATH_CHG);
                bgp_zebra_clear_route_change_flags(dest);
                return ret;
        }

        /* If the user did a "clear" this flag will be set */
        UNSET_FLAG(dest->flags, BGP_NODE_USER_CLEAR);

        /* bestpath has changed; update relevant fields and install or uninstall
         * into the zebra RIB.
         */
        if (old_select || new_select)
                bgp_bump_version(dest);

        if (old_select)
                bgp_path_info_unset_flag(dest, old_select, BGP_PATH_SELECTED);
        if (new_select) {
                bgp_path_info_set_flag(dest, new_select, BGP_PATH_SELECTED);
                bgp_path_info_unset_flag(dest, new_select,
                                         BGP_PATH_ATTR_CHANGED);
                UNSET_FLAG(new_select->flags, BGP_PATH_MULTIPATH_CHG);
        }

        if (new_select && new_select->type == ZEBRA_ROUTE_BGP
                        && new_select->sub_type == BGP_ROUTE_IMPORTED) {
                bgp_evpn_es_vtep_add(bgp, es, new_select->attr->nexthop,
                                     true /*esr */, new_select->attr->df_alg,
                                     new_select->attr->df_pref);
        } else {
                if (old_select && old_select->type == ZEBRA_ROUTE_BGP
                                && old_select->sub_type == BGP_ROUTE_IMPORTED)
                        bgp_evpn_es_vtep_del(
                                        bgp, es, old_select->attr->nexthop,
                                        true /*esr*/);
        }

        /* Clear any route change flags. */
        bgp_zebra_clear_route_change_flags(dest);

        /* Reap old select bgp_path_info, if it has been removed */
        if (old_select && CHECK_FLAG(old_select->flags, BGP_PATH_REMOVED))
                bgp_path_info_reap(dest, old_select);

        return ret;
}

/* Install Type-1/Type-4 route entry in the per-ES routing table */
static int bgp_evpn_es_route_install(struct bgp *bgp,
                struct bgp_evpn_es *es, struct prefix_evpn *p,
                struct bgp_path_info *parent_pi)
{
        int ret = 0;
        struct bgp_dest *dest = NULL;
        struct bgp_path_info *pi = NULL;
        struct attr *attr_new = NULL;

        /* Create (or fetch) route within the VNI.
         * NOTE: There is no RD here.
         */
        dest = bgp_node_get(es->route_table, (struct prefix *)p);

        /* Check if route entry is already present. */
        for (pi = bgp_dest_get_bgp_path_info(dest); pi; pi = pi->next)
                if (pi->extra
                                && (struct bgp_path_info *)pi->extra->parent ==
                                parent_pi)
                        break;

        if (!pi) {
                /* Add (or update) attribute to hash. */
                attr_new = bgp_attr_intern(parent_pi->attr);

                /* Create new route with its attribute. */
                pi = info_make(parent_pi->type, BGP_ROUTE_IMPORTED, 0,
                               parent_pi->peer, attr_new, dest);
                SET_FLAG(pi->flags, BGP_PATH_VALID);
                bgp_path_info_extra_get(pi);
                pi->extra->parent = bgp_path_info_lock(parent_pi);
                bgp_dest_lock_node((struct bgp_dest *)parent_pi->net);
                bgp_path_info_add(dest, pi);
        } else {
                if (attrhash_cmp(pi->attr, parent_pi->attr)
                                && !CHECK_FLAG(pi->flags, BGP_PATH_REMOVED)) {
                        bgp_dest_unlock_node(dest);
                        return 0;
                }
                /* The attribute has changed. */
                /* Add (or update) attribute to hash. */
                attr_new = bgp_attr_intern(parent_pi->attr);

                /* Restore route, if needed. */
                if (CHECK_FLAG(pi->flags, BGP_PATH_REMOVED))
                        bgp_path_info_restore(dest, pi);

                /* Mark if nexthop has changed. */
                if (!IPV4_ADDR_SAME(&pi->attr->nexthop, &attr_new->nexthop))
                        SET_FLAG(pi->flags, BGP_PATH_IGP_CHANGED);

                /* Unintern existing, set to new. */
                bgp_attr_unintern(&pi->attr);
                pi->attr = attr_new;
                pi->uptime = bgp_clock();
        }

        /* Perform route selection and update zebra, if required. */
        ret = bgp_evpn_es_route_select_install(bgp, es, dest);

        bgp_dest_unlock_node(dest);

        return ret;
}

/* Uninstall Type-1/Type-4 route entry from the ES routing table */
static int bgp_evpn_es_route_uninstall(struct bgp *bgp, struct bgp_evpn_es *es,
                struct prefix_evpn *p, struct bgp_path_info *parent_pi)
{
        int ret;
        struct bgp_dest *dest;
        struct bgp_path_info *pi;

        if (!es->route_table)
                return 0;

        /* Locate route within the ESI.
         * NOTE: There is no RD here.
         */
        dest = bgp_node_lookup(es->route_table, (struct prefix *)p);
        if (!dest)
                return 0;

        /* Find matching route entry. */
        for (pi = bgp_dest_get_bgp_path_info(dest); pi; pi = pi->next)
                if (pi->extra
                                && (struct bgp_path_info *)pi->extra->parent ==
                                parent_pi)
                        break;

        if (!pi) {
                bgp_dest_unlock_node(dest);
                return 0;
        }

        /* Mark entry for deletion */
        bgp_path_info_delete(dest, pi);

        /* Perform route selection and update zebra, if required. */
        ret = bgp_evpn_es_route_select_install(bgp, es, dest);

        /* Unlock route node. */
        bgp_dest_unlock_node(dest);

        return ret;
}

/* Install or unistall a Tyoe-4 route in the per-ES routing table */
int bgp_evpn_es_route_install_uninstall(struct bgp *bgp, struct bgp_evpn_es *es,
                afi_t afi, safi_t safi, struct prefix_evpn *evp,
                struct bgp_path_info *pi, int install)
{
        int ret = 0;

        if (install)
                ret = bgp_evpn_es_route_install(bgp, es, evp, pi);
        else
                ret = bgp_evpn_es_route_uninstall(bgp, es, evp, pi);

        if (ret) {
                flog_err(
                                EC_BGP_EVPN_FAIL,
                                "%u: Failed to %s EVPN %s route in ESI %s",
                                bgp->vrf_id,
                                install ? "install" : "uninstall",
                                "ES", es->esi_str);
                return ret;
        }
        return 0;
}

/* Delete (and withdraw) local routes for specified ES from global and ES table.
 * Also remove all remote routes from the per ES table. Invoked when ES
 * is deleted.
 */
static void bgp_evpn_es_route_del_all(struct bgp *bgp, struct bgp_evpn_es *es)
{
        struct bgp_dest *dest;
        struct bgp_path_info *pi, *nextpi;

        /* de-activate the ES */
        bgp_evpn_local_es_down(bgp, es);
        bgp_evpn_local_type1_evi_route_del(bgp, es);

        /* Walk this ES's routing table and delete all routes. */
        for (dest = bgp_table_top(es->route_table); dest;
             dest = bgp_route_next(dest)) {
                for (pi = bgp_dest_get_bgp_path_info(dest);
                     (pi != NULL) && (nextpi = pi->next, 1); pi = nextpi) {
                        bgp_path_info_delete(dest, pi);
                        bgp_path_info_reap(dest, pi);
                }
        }
}

/*****************************************************************************
 * Base APIs for creating MH routes (Type-1 or Type-4) on local ethernet
 * segment updates.
 */

/* create or update local EVPN type1/type4 route entry.
 *
 * This could be in -
 *     the ES table if ESR/EAD-ES (or)
 *     the VNI table if EAD-EVI (or)
 *     the global table if ESR/EAD-ES/EAD-EVI
 *
 * Note: vpn is applicable only to EAD-EVI routes (NULL for EAD-ES and
 * ESR).
 */
int bgp_evpn_mh_route_update(struct bgp *bgp, struct bgp_evpn_es *es,
                             struct bgpevpn *vpn, afi_t afi, safi_t safi,
                             struct bgp_dest *dest, struct attr *attr, int add,
                             struct bgp_path_info **ri, int *route_changed)
{
        struct bgp_path_info *tmp_pi = NULL;
        struct bgp_path_info *local_pi = NULL;  /* local route entry if any */
        struct bgp_path_info *remote_pi = NULL; /* remote route entry if any */
        struct attr *attr_new = NULL;
        struct prefix_evpn *evp;

        *ri = NULL;
        evp = (struct prefix_evpn *)bgp_dest_get_prefix(dest);
        *route_changed = 1;

        /* locate the local and remote entries if any */
        for (tmp_pi = bgp_dest_get_bgp_path_info(dest); tmp_pi;
             tmp_pi = tmp_pi->next) {
                if (tmp_pi->peer == bgp->peer_self
                                && tmp_pi->type == ZEBRA_ROUTE_BGP
                                && tmp_pi->sub_type == BGP_ROUTE_STATIC)
                        local_pi = tmp_pi;
                if (tmp_pi->type == ZEBRA_ROUTE_BGP
                                && tmp_pi->sub_type == BGP_ROUTE_IMPORTED
                                && CHECK_FLAG(tmp_pi->flags, BGP_PATH_VALID))
                        remote_pi = tmp_pi;
        }

        /* we don't expect to see a remote_ri at this point as
         * an ES route has {esi, vtep_ip} as the key in the ES-rt-table
         * in the VNI-rt-table.
         */
        if (remote_pi) {
                flog_err(
                        EC_BGP_ES_INVALID,
                        "%u ERROR: local es route for ESI: %s Vtep %pI4 also learnt from remote",
                        bgp->vrf_id, es ? es->esi_str : "Null",
                        &es->originator_ip);
                return -1;
        }

        if (!local_pi && !add)
                return 0;

        /* create or update the entry */
        if (!local_pi) {

                /* Add or update attribute to hash */
                attr_new = bgp_attr_intern(attr);

                /* Create new route with its attribute. */
                tmp_pi = info_make(ZEBRA_ROUTE_BGP, BGP_ROUTE_STATIC, 0,
                                   bgp->peer_self, attr_new, dest);
                SET_FLAG(tmp_pi->flags, BGP_PATH_VALID);

                if (evp->prefix.route_type == BGP_EVPN_AD_ROUTE) {
                        bgp_path_info_extra_get(tmp_pi);
                        tmp_pi->extra->num_labels = 1;
                        if (vpn)
                                vni2label(vpn->vni, &tmp_pi->extra->label[0]);
                        else
                                tmp_pi->extra->label[0] = 0;
                }

                /* add the newly created path to the route-node */
                bgp_path_info_add(dest, tmp_pi);
        } else {
                tmp_pi = local_pi;
                if (attrhash_cmp(tmp_pi->attr, attr)
                                && !CHECK_FLAG(tmp_pi->flags, BGP_PATH_REMOVED))
                        *route_changed = 0;
                else {
                        /* The attribute has changed.
                         * Add (or update) attribute to hash.
                         */
                        attr_new = bgp_attr_intern(attr);
                        bgp_path_info_set_flag(dest, tmp_pi,
                                               BGP_PATH_ATTR_CHANGED);

                        /* Restore route, if needed. */
                        if (CHECK_FLAG(tmp_pi->flags, BGP_PATH_REMOVED))
                                bgp_path_info_restore(dest, tmp_pi);

                        /* Unintern existing, set to new. */
                        bgp_attr_unintern(&tmp_pi->attr);
                        tmp_pi->attr = attr_new;
                        tmp_pi->uptime = bgp_clock();
                }
        }

        if (*route_changed) {
                if (BGP_DEBUG(evpn_mh, EVPN_MH_RT))
                        zlog_debug(
                                "local ES %s vni %u route-type %s nexthop %pI4 updated",
                                es ? es->esi_str : "Null", vpn ? vpn->vni : 0,
                                evp->prefix.route_type == BGP_EVPN_ES_ROUTE
                                        ? "esr"
                                        : (vpn ? "ead-evi" : "ead-es"),
                                &attr->mp_nexthop_global_in);
        }

        /* Return back the route entry. */
        *ri = tmp_pi;
        return 0;
}

/* Delete local EVPN ESR (type-4) and EAD (type-1) route
 *
 * Note: vpn is applicable only to EAD-EVI routes (NULL for EAD-ES and
 * ESR).
 */
static int bgp_evpn_mh_route_delete(struct bgp *bgp, struct bgp_evpn_es *es,
                                    struct bgpevpn *vpn,
                                    struct bgp_evpn_es_frag *es_frag,
                                    struct prefix_evpn *p)
{
        afi_t afi = AFI_L2VPN;
        safi_t safi = SAFI_EVPN;
        struct bgp_path_info *pi;
        struct bgp_dest *dest = NULL;        /* dest in esi table */
        struct bgp_dest *global_dest = NULL; /* dest in global table */
        struct bgp_table *rt_table;
        struct prefix_rd *prd;

        if (vpn) {
                rt_table = vpn->route_table;
                prd = &vpn->prd;
        } else {
                rt_table = es->route_table;
                prd = &es_frag->prd;
        }

        /* First, locate the route node within the ESI or VNI.
         * If it doesn't exist, ther is nothing to do.
         * Note: there is no RD here.
         */
        dest = bgp_node_lookup(rt_table, (struct prefix *)p);
        if (!dest)
                return 0;

        if (BGP_DEBUG(evpn_mh, EVPN_MH_RT))
                zlog_debug(
                        "local ES %s vni %u route-type %s nexthop %pI4 delete",
                        es->esi_str, vpn ? vpn->vni : 0,
                        p->prefix.route_type == BGP_EVPN_ES_ROUTE
                                ? "esr"
                                : (vpn ? "ead-evi" : "ead-es"),
                        &es->originator_ip);

        /* Next, locate route node in the global EVPN routing table.
         * Note that this table is a 2-level tree (RD-level + Prefix-level)
         */
        global_dest =
                bgp_global_evpn_node_lookup(bgp->rib[afi][safi], afi, safi,
                                            (const struct prefix_evpn *)p, prd);
        if (global_dest) {

                /* Delete route entry in the global EVPN table. */
                delete_evpn_route_entry(bgp, afi, safi, global_dest, &pi);

                /* Schedule for processing - withdraws to peers happen from
                 * this table.
                 */
                if (pi)
                        bgp_process(bgp, global_dest, afi, safi);
                bgp_dest_unlock_node(global_dest);
        }

        /*
         * Delete route entry in the ESI or VNI routing table.
         * This can just be removed.
         */
        delete_evpn_route_entry(bgp, afi, safi, dest, &pi);
        if (pi)
                bgp_path_info_reap(dest, pi);
        bgp_dest_unlock_node(dest);
        return 0;
}

/*
 * This function is called when the VNI RD changes.
 * Delete all EAD/EVI local routes for this VNI from the global routing table.
 * These routes are scheduled for withdraw from peers.
 */
int delete_global_ead_evi_routes(struct bgp *bgp, struct bgpevpn *vpn)
{
        afi_t afi;
        safi_t safi;
        struct bgp_dest *rdrn, *rn;
        struct bgp_table *table;
        struct bgp_path_info *pi;

        afi = AFI_L2VPN;
        safi = SAFI_EVPN;

        /* Find the RD node for the VNI in the global table */
        rdrn = bgp_node_lookup(bgp->rib[afi][safi], (struct prefix *)&vpn->prd);
        if (rdrn && bgp_dest_has_bgp_path_info_data(rdrn)) {
                table = bgp_dest_get_bgp_table_info(rdrn);

                /*
                 * Iterate over all the routes in this table and delete EAD/EVI
                 * routes
                 */
                for (rn = bgp_table_top(table); rn; rn = bgp_route_next(rn)) {
                        struct prefix_evpn *evp = (struct prefix_evpn *)&rn->p;

                        if (evp->prefix.route_type != BGP_EVPN_AD_ROUTE)
                                continue;

                        delete_evpn_route_entry(bgp, afi, safi, rn, &pi);
                        if (pi)
                                bgp_process(bgp, rn, afi, safi);
                }
        }

        /* Unlock RD node. */
        if (rdrn)
                bgp_dest_unlock_node(rdrn);

        return 0;
}

/*****************************************************************************
 * Ethernet Segment (Type-4) Routes
 * ESRs are used for DF election. Currently service-carving described in
 * RFC 7432 is NOT supported. Instead preference based DF election is
 * used by default.
 * Reference: draft-ietf-bess-evpn-pref-df
 */
/* Build extended community for EVPN ES (type-4) route */
static void bgp_evpn_type4_route_extcomm_build(struct bgp_evpn_es *es,
                struct attr *attr)
{
        struct ecommunity ecom_encap;
        struct ecommunity ecom_es_rt;
        struct ecommunity ecom_df;
        struct ecommunity_val eval;
        struct ecommunity_val eval_es_rt;
        struct ecommunity_val eval_df;
        bgp_encap_types tnl_type;
        struct ethaddr mac;

        /* Encap */
        tnl_type = BGP_ENCAP_TYPE_VXLAN;
        memset(&ecom_encap, 0, sizeof(ecom_encap));
        encode_encap_extcomm(tnl_type, &eval);
        ecom_encap.size = 1;
        ecom_encap.unit_size = ECOMMUNITY_SIZE;
        ecom_encap.val = (uint8_t *)eval.val;
        bgp_attr_set_ecommunity(attr, ecommunity_dup(&ecom_encap));

        /* ES import RT */
        memset(&mac, 0, sizeof(struct ethaddr));
        memset(&ecom_es_rt, 0, sizeof(ecom_es_rt));
        es_get_system_mac(&es->esi, &mac);
        encode_es_rt_extcomm(&eval_es_rt, &mac);
        ecom_es_rt.size = 1;
        ecom_es_rt.unit_size = ECOMMUNITY_SIZE;
        ecom_es_rt.val = (uint8_t *)eval_es_rt.val;
        bgp_attr_set_ecommunity(
                attr,
                ecommunity_merge(bgp_attr_get_ecommunity(attr), &ecom_es_rt));

        /* DF election extended community */
        memset(&ecom_df, 0, sizeof(ecom_df));
        encode_df_elect_extcomm(&eval_df, es->df_pref);
        ecom_df.size = 1;
        ecom_df.val = (uint8_t *)eval_df.val;
        bgp_attr_set_ecommunity(
                attr,
                ecommunity_merge(bgp_attr_get_ecommunity(attr), &ecom_df));

        attr->flag |= ATTR_FLAG_BIT(BGP_ATTR_EXT_COMMUNITIES);
}

/* Create or update local type-4 route */
static int bgp_evpn_type4_route_update(struct bgp *bgp,
                struct bgp_evpn_es *es, struct prefix_evpn *p)
{
        int ret = 0;
        int route_changed = 0;
        afi_t afi = AFI_L2VPN;
        safi_t safi = SAFI_EVPN;
        struct attr attr;
        struct attr *attr_new = NULL;
        struct bgp_dest *dest = NULL;
        struct bgp_path_info *pi = NULL;

        memset(&attr, 0, sizeof(struct attr));

        /* Build path-attribute for this route. */
        bgp_attr_default_set(&attr, BGP_ORIGIN_IGP);
        attr.nexthop = es->originator_ip;
        attr.mp_nexthop_global_in = es->originator_ip;
        attr.mp_nexthop_len = BGP_ATTR_NHLEN_IPV4;

        /* Set up extended community. */
        bgp_evpn_type4_route_extcomm_build(es, &attr);

        /* First, create (or fetch) route node within the ESI. */
        /* NOTE: There is no RD here. */
        dest = bgp_node_get(es->route_table, (struct prefix *)p);

        /* Create or update route entry. */
        ret = bgp_evpn_mh_route_update(bgp, es, NULL, afi, safi, dest, &attr, 1,
                                       &pi, &route_changed);
        if (ret != 0)
                flog_err(
                        EC_BGP_ES_INVALID,
                        "%u ERROR: Failed to updated ES route ESI: %s VTEP %pI4",
                        bgp->vrf_id, es->esi_str, &es->originator_ip);

        assert(pi);
        attr_new = pi->attr;

        /* Perform route selection;
         * this is just to set the flags correctly
         * as local route in the ES always wins.
         */
        bgp_evpn_es_route_select_install(bgp, es, dest);
        bgp_dest_unlock_node(dest);

        /* If this is a new route or some attribute has changed, export the
         * route to the global table. The route will be advertised to peers
         * from there. Note that this table is a 2-level tree (RD-level +
         * Prefix-level) similar to L3VPN routes.
         */
        if (route_changed) {
                struct bgp_path_info *global_pi;

                dest = bgp_global_evpn_node_get(bgp->rib[afi][safi], afi, safi,
                                                p, &es->es_base_frag->prd);
                bgp_evpn_mh_route_update(bgp, es, NULL, afi, safi, dest,
                                         attr_new, 1, &global_pi,
                                         &route_changed);

                /* Schedule for processing and unlock node. */
                bgp_process(bgp, dest, afi, safi);
                bgp_dest_unlock_node(dest);
        }

        /* Unintern temporary. */
        aspath_unintern(&attr.aspath);
        return 0;
}

/* Delete local type-4 route */
static int bgp_evpn_type4_route_delete(struct bgp *bgp,
                struct bgp_evpn_es *es, struct prefix_evpn *p)
{
        if (!es->es_base_frag)
                return -1;

        return bgp_evpn_mh_route_delete(bgp, es, NULL /* l2vni */,
                                        es->es_base_frag, p);
}

/* Process remote/received EVPN type-4 route (advertise or withdraw)  */
int bgp_evpn_type4_route_process(struct peer *peer, afi_t afi, safi_t safi,
                struct attr *attr, uint8_t *pfx, int psize,
                uint32_t addpath_id)
{
        int ret;
        esi_t esi;
        uint8_t ipaddr_len;
        struct in_addr vtep_ip;
        struct prefix_rd prd;
        struct prefix_evpn p;

        /* Type-4 route should be either 23 or 35 bytes
         *  RD (8), ESI (10), ip-len (1), ip (4 or 16)
         */
        if (psize != BGP_EVPN_TYPE4_V4_PSIZE &&
                        psize != BGP_EVPN_TYPE4_V6_PSIZE) {
                flog_err(EC_BGP_EVPN_ROUTE_INVALID,
                                "%u:%s - Rx EVPN Type-4 NLRI with invalid length %d",
                                peer->bgp->vrf_id, peer->host, psize);
                return -1;
        }

        /* Make prefix_rd */
        prd.family = AF_UNSPEC;
        prd.prefixlen = 64;
        memcpy(&prd.val, pfx, RD_BYTES);
        pfx += RD_BYTES;

        /* get the ESI */
        memcpy(&esi, pfx, ESI_BYTES);
        pfx += ESI_BYTES;


        /* Get the IP. */
        ipaddr_len = *pfx++;
        if (ipaddr_len == IPV4_MAX_BITLEN) {
                memcpy(&vtep_ip, pfx, IPV4_MAX_BYTELEN);
        } else {
                flog_err(
                                EC_BGP_EVPN_ROUTE_INVALID,
                                "%u:%s - Rx EVPN Type-4 NLRI with unsupported IP address length %d",
                                peer->bgp->vrf_id, peer->host, ipaddr_len);
                return -1;
        }

        build_evpn_type4_prefix(&p, &esi, vtep_ip);
        /* Process the route. */
        if (attr) {
                ret = bgp_update(peer, (struct prefix *)&p, addpath_id, attr,
                                afi, safi, ZEBRA_ROUTE_BGP, BGP_ROUTE_NORMAL,
                                &prd, NULL, 0, 0, NULL);
        } else {
                ret = bgp_withdraw(peer, (struct prefix *)&p, addpath_id, attr,
                                afi, safi, ZEBRA_ROUTE_BGP, BGP_ROUTE_NORMAL,
                                &prd, NULL, 0, NULL);
        }
        return ret;
}

/* Check if a prefix belongs to the local ES */
static bool bgp_evpn_type4_prefix_match(struct prefix_evpn *p,
                struct bgp_evpn_es *es)
{
        return (p->prefix.route_type == BGP_EVPN_ES_ROUTE) &&
                !memcmp(&p->prefix.es_addr.esi, &es->esi, sizeof(esi_t));
}

/* Import remote ESRs on local ethernet segment add  */
static int bgp_evpn_type4_remote_routes_import(struct bgp *bgp,
                struct bgp_evpn_es *es, bool install)
{
        int ret;
        afi_t afi;
        safi_t safi;
        struct bgp_dest *rd_dest, *dest;
        struct bgp_table *table;
        struct bgp_path_info *pi;

        afi = AFI_L2VPN;
        safi = SAFI_EVPN;

        /* Walk entire global routing table and evaluate routes which could be
         * imported into this Ethernet Segment.
         */
        for (rd_dest = bgp_table_top(bgp->rib[afi][safi]); rd_dest;
             rd_dest = bgp_route_next(rd_dest)) {
                table = bgp_dest_get_bgp_table_info(rd_dest);
                if (!table)
                        continue;

                for (dest = bgp_table_top(table); dest;
                     dest = bgp_route_next(dest)) {
                        struct prefix_evpn *evp =
                                (struct prefix_evpn *)bgp_dest_get_prefix(dest);

                        for (pi = bgp_dest_get_bgp_path_info(dest); pi;
                             pi = pi->next) {
                                /*
                                 * Consider "valid" remote routes applicable for
                                 * this ES.
                                 */
                                if (!(CHECK_FLAG(pi->flags, BGP_PATH_VALID)
                                        && pi->type == ZEBRA_ROUTE_BGP
                                        && pi->sub_type == BGP_ROUTE_NORMAL))
                                        continue;

                                if (!bgp_evpn_type4_prefix_match(evp, es))
                                        continue;

                                if (install)
                                        ret = bgp_evpn_es_route_install(
                                                        bgp, es, evp, pi);
                                else
                                        ret = bgp_evpn_es_route_uninstall(
                                                        bgp, es, evp, pi);

                                if (ret) {
                                        flog_err(
                                                EC_BGP_EVPN_FAIL,
                                                "Failed to %s EVPN %pFX route in ESI %s",
                                                install ? "install"
                                                        : "uninstall",
                                                evp, es->esi_str);

                                        bgp_dest_unlock_node(rd_dest);
                                        bgp_dest_unlock_node(dest);
                                        return ret;
                                }
                        }
                }
        }
        return 0;
}

/*****************************************************************************
 * Ethernet Auto Discovery (EAD/Type-1) route handling
 * There are two types of EAD routes -
 * 1. EAD-per-ES - Key: {ESI, ET=0xffffffff}
 * 2. EAD-per-EVI - Key: {ESI, ET=0}
 */

/* Extended communities associated with EAD-per-ES */
static void
bgp_evpn_type1_es_route_extcomm_build(struct bgp_evpn_es_frag *es_frag,
                                      struct attr *attr)
{
        struct ecommunity ecom_encap;
        struct ecommunity ecom_esi_label;
        struct ecommunity_val eval;
        struct ecommunity_val eval_esi_label;
        bgp_encap_types tnl_type;
        struct listnode *evi_node, *rt_node;
        struct ecommunity *ecom;
        struct bgp_evpn_es_evi *es_evi;

        /* Encap */
        tnl_type = BGP_ENCAP_TYPE_VXLAN;
        memset(&ecom_encap, 0, sizeof(ecom_encap));
        encode_encap_extcomm(tnl_type, &eval);
        ecom_encap.size = 1;
        ecom_encap.unit_size = ECOMMUNITY_SIZE;
        ecom_encap.val = (uint8_t *)eval.val;
        bgp_attr_set_ecommunity(attr, ecommunity_dup(&ecom_encap));

        /* ESI label */
        encode_esi_label_extcomm(&eval_esi_label,
                        false /*single_active*/);
        ecom_esi_label.size = 1;
        ecom_esi_label.unit_size = ECOMMUNITY_SIZE;
        ecom_esi_label.val = (uint8_t *)eval_esi_label.val;
        bgp_attr_set_ecommunity(attr,
                                ecommunity_merge(bgp_attr_get_ecommunity(attr),
                                                 &ecom_esi_label));

        /* Add export RTs for all L2-VNIs associated with this ES */
        /* XXX - suppress EAD-ES advertisment if there are no EVIs associated
         * with it.
         */
        if (listcount(bgp_mh_info->ead_es_export_rtl)) {
                for (ALL_LIST_ELEMENTS_RO(bgp_mh_info->ead_es_export_rtl,
                                          rt_node, ecom))
                        bgp_attr_set_ecommunity(
                                attr, ecommunity_merge(attr->ecommunity, ecom));
        } else {
                for (ALL_LIST_ELEMENTS_RO(es_frag->es_evi_frag_list, evi_node,
                                          es_evi)) {
                        if (!CHECK_FLAG(es_evi->flags, BGP_EVPNES_EVI_LOCAL))
                                continue;
                        for (ALL_LIST_ELEMENTS_RO(es_evi->vpn->export_rtl,
                                                  rt_node, ecom))
                                bgp_attr_set_ecommunity(
                                        attr, ecommunity_merge(attr->ecommunity,
                                                               ecom));
                }
        }

        attr->flag |= ATTR_FLAG_BIT(BGP_ATTR_EXT_COMMUNITIES);
}

/* Extended communities associated with EAD-per-EVI */
static void bgp_evpn_type1_evi_route_extcomm_build(struct bgp_evpn_es *es,
                struct bgpevpn *vpn, struct attr *attr)
{
        struct ecommunity ecom_encap;
        struct ecommunity_val eval;
        bgp_encap_types tnl_type;
        struct listnode *rt_node;
        struct ecommunity *ecom;

        /* Encap */
        tnl_type = BGP_ENCAP_TYPE_VXLAN;
        memset(&ecom_encap, 0, sizeof(ecom_encap));
        encode_encap_extcomm(tnl_type, &eval);
        ecom_encap.size = 1;
        ecom_encap.unit_size = ECOMMUNITY_SIZE;
        ecom_encap.val = (uint8_t *)eval.val;
        bgp_attr_set_ecommunity(attr, ecommunity_dup(&ecom_encap));

        /* Add export RTs for the L2-VNI */
        for (ALL_LIST_ELEMENTS_RO(vpn->export_rtl, rt_node, ecom))
                bgp_attr_set_ecommunity(
                        attr,
                        ecommunity_merge(bgp_attr_get_ecommunity(attr), ecom));

        attr->flag |= ATTR_FLAG_BIT(BGP_ATTR_EXT_COMMUNITIES);
}

/* Update EVPN EAD (type-1) route -
 * vpn - valid for EAD-EVI routes and NULL for EAD-ES routes
 */
static int bgp_evpn_type1_route_update(struct bgp *bgp, struct bgp_evpn_es *es,
                                       struct bgpevpn *vpn,
                                       struct bgp_evpn_es_frag *es_frag,
                                       struct prefix_evpn *p)
{
        int ret = 0;
        afi_t afi = AFI_L2VPN;
        safi_t safi = SAFI_EVPN;
        struct attr attr;
        struct attr *attr_new = NULL;
        struct bgp_dest *dest = NULL;
        struct bgp_path_info *pi = NULL;
        int route_changed = 0;
        struct prefix_rd *global_rd;

        memset(&attr, 0, sizeof(struct attr));

        /* Build path-attribute for this route. */
        bgp_attr_default_set(&attr, BGP_ORIGIN_IGP);
        attr.nexthop = es->originator_ip;
        attr.mp_nexthop_global_in = es->originator_ip;
        attr.mp_nexthop_len = BGP_ATTR_NHLEN_IPV4;

        if (vpn) {
                /* EAD-EVI route update */
                /* MPLS label */
                vni2label(vpn->vni, &(attr.label));

                /* Set up extended community */
                bgp_evpn_type1_evi_route_extcomm_build(es, vpn, &attr);

                /* First, create (or fetch) route node within the VNI. */
                dest = bgp_node_get(vpn->route_table, (struct prefix *)p);

                /* Create or update route entry. */
                ret = bgp_evpn_mh_route_update(bgp, es, vpn, afi, safi, dest,
                                               &attr, 1, &pi, &route_changed);
                if (ret != 0)
                        flog_err(
                                EC_BGP_ES_INVALID,
                                "%u Failed to update EAD-EVI route ESI: %s VNI %u VTEP %pI4",
                                bgp->vrf_id, es->esi_str, vpn->vni,
                                &es->originator_ip);
                global_rd = &vpn->prd;
        } else {
                /* EAD-ES route update */
                /* MPLS label is 0 for EAD-ES route */

                /* Set up extended community */
                bgp_evpn_type1_es_route_extcomm_build(es_frag, &attr);

                /* First, create (or fetch) route node within the ES. */
                /* NOTE: There is no RD here. */
                /* XXX: fragment ID must be included as a part of the prefix. */
                dest = bgp_node_get(es->route_table, (struct prefix *)p);

                /* Create or update route entry. */
                ret = bgp_evpn_mh_route_update(bgp, es, vpn, afi, safi, dest,
                                               &attr, 1, &pi, &route_changed);
                if (ret != 0) {
                        flog_err(
                                EC_BGP_ES_INVALID,
                                "%u ERROR: Failed to updated EAD-EVI route ESI: %s VTEP %pI4",
                                bgp->vrf_id, es->esi_str, &es->originator_ip);
                }
                global_rd = &es_frag->prd;
        }


        assert(pi);
        attr_new = pi->attr;

        /* Perform route selection;
         * this is just to set the flags correctly as local route in
         * the ES always wins.
         */
        evpn_route_select_install(bgp, vpn, dest);
        bgp_dest_unlock_node(dest);

        /* If this is a new route or some attribute has changed, export the
         * route to the global table. The route will be advertised to peers
         * from there. Note that this table is a 2-level tree (RD-level +
         * Prefix-level) similar to L3VPN routes.
         */
        if (route_changed) {
                struct bgp_path_info *global_pi;

                dest = bgp_global_evpn_node_get(bgp->rib[afi][safi], afi, safi,
                                                p, global_rd);
                bgp_evpn_mh_route_update(bgp, es, vpn, afi, safi, dest,
                                         attr_new, 1, &global_pi,
                                         &route_changed);

                /* Schedule for processing and unlock node. */
                bgp_process(bgp, dest, afi, safi);
                bgp_dest_unlock_node(dest);
        }

        /* Unintern temporary. */
        aspath_unintern(&attr.aspath);
        return 0;
}

/*
 * This function is called when the export RT for a VNI changes.
 * Update all type-1 local routes for this VNI from VNI/ES tables and the global
 * table and advertise these routes to peers.
 */

static void bgp_evpn_ead_es_route_update(struct bgp *bgp,
                                         struct bgp_evpn_es *es)
{
        struct listnode *node;
        struct bgp_evpn_es_frag *es_frag;
        struct prefix_evpn p;

        build_evpn_type1_prefix(&p, BGP_EVPN_AD_ES_ETH_TAG, &es->esi,
                                es->originator_ip);
        for (ALL_LIST_ELEMENTS_RO(es->es_frag_list, node, es_frag)) {
                if (!listcount(es_frag->es_evi_frag_list))
                        continue;

                p.prefix.ead_addr.frag_id = es_frag->rd_id;
                if (bgp_evpn_type1_route_update(bgp, es, NULL, es_frag, &p))
                        flog_err(
                                EC_BGP_EVPN_ROUTE_CREATE,
                                "EAD-ES route creation failure for ESI %s frag %u",
                                es->esi_str, es_frag->rd_id);
        }
}

static void bgp_evpn_ead_evi_route_update(struct bgp *bgp,
                                          struct bgp_evpn_es *es,
                                          struct bgpevpn *vpn,
                                          struct prefix_evpn *p)
{
        if (bgp_evpn_type1_route_update(bgp, es, vpn, NULL, p))
                flog_err(EC_BGP_EVPN_ROUTE_CREATE,
                         "EAD-EVI route creation failure for ESI %s VNI %u",
                         es->esi_str, vpn->vni);
}

void update_type1_routes_for_evi(struct bgp *bgp, struct bgpevpn *vpn)
{
        struct prefix_evpn p;
        struct bgp_evpn_es *es;
        struct bgp_evpn_es_evi *es_evi;


        RB_FOREACH (es_evi, bgp_es_evi_rb_head, &vpn->es_evi_rb_tree) {
                es = es_evi->es;

                if (es_evi->vpn != vpn)
                        continue;

                /* Update EAD-ES */
                bgp_evpn_ead_es_route_update(bgp, es);

                /* Update EAD-EVI */
                if (CHECK_FLAG(es->flags, BGP_EVPNES_ADV_EVI)) {
                        build_evpn_type1_prefix(&p, BGP_EVPN_AD_EVI_ETH_TAG,
                                                &es->esi, es->originator_ip);
                        bgp_evpn_ead_evi_route_update(bgp, es, vpn, &p);
                }
        }
}

/* Delete local Type-1 route */
static void bgp_evpn_ead_es_route_delete(struct bgp *bgp,
                                         struct bgp_evpn_es *es)
{
        struct listnode *node;
        struct bgp_evpn_es_frag *es_frag;
        struct prefix_evpn p;

        build_evpn_type1_prefix(&p, BGP_EVPN_AD_ES_ETH_TAG, &es->esi,
                                es->originator_ip);
        for (ALL_LIST_ELEMENTS_RO(es->es_frag_list, node, es_frag)) {
                p.prefix.ead_addr.frag_id = es_frag->rd_id;
                bgp_evpn_mh_route_delete(bgp, es, NULL, es_frag, &p);
        }
}

static int bgp_evpn_ead_evi_route_delete(struct bgp *bgp,
                                         struct bgp_evpn_es *es,
                                         struct bgpevpn *vpn,
                                         struct prefix_evpn *p)
{
        return bgp_evpn_mh_route_delete(bgp, es, vpn, NULL, p);
}

/* Generate EAD-EVI for all VNIs */
static void bgp_evpn_local_type1_evi_route_add(struct bgp *bgp,
                struct bgp_evpn_es *es)
{
        struct listnode *evi_node;
        struct prefix_evpn p;
        struct bgp_evpn_es_evi *es_evi;

        /* EAD-per-EVI routes have been suppressed */
        if (!bgp_mh_info->ead_evi_tx)
                return;

        if (CHECK_FLAG(es->flags, BGP_EVPNES_ADV_EVI))
                /* EAD-EVI route add for this ES is already done */
                return;

        SET_FLAG(es->flags, BGP_EVPNES_ADV_EVI);
        build_evpn_type1_prefix(&p, BGP_EVPN_AD_EVI_ETH_TAG,
                        &es->esi, es->originator_ip);

        for (ALL_LIST_ELEMENTS_RO(es->es_evi_list, evi_node, es_evi)) {
                if (!CHECK_FLAG(es_evi->flags, BGP_EVPNES_EVI_LOCAL))
                        continue;
                bgp_evpn_ead_evi_route_update(bgp, es, es_evi->vpn, &p);
        }
}

/*
 * Withdraw EAD-EVI for all VNIs
 */
static void bgp_evpn_local_type1_evi_route_del(struct bgp *bgp,
                struct bgp_evpn_es *es)
{
        struct listnode *evi_node;
        struct prefix_evpn p;
        struct bgp_evpn_es_evi *es_evi;

        /* Delete and withdraw locally learnt EAD-EVI route */
        if (!CHECK_FLAG(es->flags, BGP_EVPNES_ADV_EVI))
                /* EAD-EVI route has not been advertised for this ES */
                return;

        UNSET_FLAG(es->flags, BGP_EVPNES_ADV_EVI);
        build_evpn_type1_prefix(&p, BGP_EVPN_AD_EVI_ETH_TAG,
                        &es->esi, es->originator_ip);
        for (ALL_LIST_ELEMENTS_RO(es->es_evi_list, evi_node, es_evi)) {
                if (!CHECK_FLAG(es_evi->flags, BGP_EVPNES_EVI_LOCAL))
                        continue;
                if (bgp_evpn_mh_route_delete(bgp, es, es_evi->vpn, NULL, &p))
                        flog_err(EC_BGP_EVPN_ROUTE_CREATE,
                                        "%u: Type4 route creation failure for ESI %s",
                                        bgp->vrf_id, es->esi_str);
        }
}

/*
 * Process received EVPN type-1 route (advertise or withdraw).
 */
int bgp_evpn_type1_route_process(struct peer *peer, afi_t afi, safi_t safi,
                struct attr *attr, uint8_t *pfx, int psize,
                uint32_t addpath_id)
{
        int ret;
        struct prefix_rd prd;
        esi_t esi;
        uint32_t eth_tag;
        mpls_label_t label;
        struct in_addr vtep_ip;
        struct prefix_evpn p;

        if (psize != BGP_EVPN_TYPE1_PSIZE) {
                flog_err(EC_BGP_EVPN_ROUTE_INVALID,
                                "%u:%s - Rx EVPN Type-1 NLRI with invalid length %d",
                                peer->bgp->vrf_id, peer->host, psize);
                return -1;
        }

        /* Make prefix_rd */
        prd.family = AF_UNSPEC;
        prd.prefixlen = 64;
        memcpy(&prd.val, pfx, RD_BYTES);
        pfx += RD_BYTES;

        /* get the ESI */
        memcpy(&esi, pfx, ESI_BYTES);
        pfx += ESI_BYTES;

        /* Copy Ethernet Tag */
        memcpy(&eth_tag, pfx, EVPN_ETH_TAG_BYTES);
        eth_tag = ntohl(eth_tag);
        pfx += EVPN_ETH_TAG_BYTES;

        memcpy(&label, pfx, BGP_LABEL_BYTES);

        /* EAD route prefix doesn't include the nexthop in the global
         * table
         */
        vtep_ip.s_addr = INADDR_ANY;
        build_evpn_type1_prefix(&p, eth_tag, &esi, vtep_ip);
        /* Process the route. */
        if (attr) {
                ret = bgp_update(peer, (struct prefix *)&p, addpath_id, attr,
                                afi, safi, ZEBRA_ROUTE_BGP, BGP_ROUTE_NORMAL,
                                &prd, NULL, 0, 0, NULL);
        } else {
                ret = bgp_withdraw(peer, (struct prefix *)&p, addpath_id, attr,
                                afi, safi, ZEBRA_ROUTE_BGP, BGP_ROUTE_NORMAL,
                                &prd, NULL, 0, NULL);
        }
        return ret;
}

void bgp_evpn_mh_config_ead_export_rt(struct bgp *bgp,
                                      struct ecommunity *ecomcfg, bool del)
{
        struct listnode *node, *nnode, *node_to_del;
        struct ecommunity *ecom;
        struct bgp_evpn_es *es;

        if (del) {
                if (ecomcfg == NULL) {
                        /* Reset to default and process all routes. */
                        for (ALL_LIST_ELEMENTS(bgp_mh_info->ead_es_export_rtl,
                                               node, nnode, ecom)) {
                                ecommunity_free(&ecom);
                                list_delete_node(bgp_mh_info->ead_es_export_rtl,
                                                 node);
                        }
                }

                /* Delete a specific export RT */
                else {
                        node_to_del = NULL;

                        for (ALL_LIST_ELEMENTS(bgp_mh_info->ead_es_export_rtl,
                                               node, nnode, ecom)) {
                                if (ecommunity_match(ecom, ecomcfg)) {
                                        ecommunity_free(&ecom);
                                        node_to_del = node;
                                        break;
                                }
                        }

                        if (node_to_del)
                                list_delete_node(bgp_mh_info->ead_es_export_rtl,
                                                 node_to_del);
                }
        } else {
                listnode_add_sort(bgp_mh_info->ead_es_export_rtl, ecomcfg);
        }

        if (BGP_DEBUG(evpn_mh, EVPN_MH_RT))
                zlog_debug("local ES del/re-add EAD route on export RT change");
        /*
         * walk through all active ESs withdraw the old EAD and
         * generate a new one
         */
        RB_FOREACH (es, bgp_es_rb_head, &bgp_mh_info->es_rb_tree) {
                if (!bgp_evpn_is_es_local(es) ||
                    !bgp_evpn_local_es_is_active(es))
                        continue;

                if (BGP_DEBUG(evpn_mh, EVPN_MH_RT))
                        zlog_debug(
                                "local ES %s del/re-add EAD route on export RT change",
                                es->esi_str);

                /*
                 * withdraw EAD-ES. XXX - this should technically not be
                 * needed; can be removed after testing
                 */
                bgp_evpn_ead_es_route_delete(bgp, es);

                /* generate EAD-ES */
                bgp_evpn_ead_es_route_update(bgp, es);
        }
}

/*****************************************************************************/
/* Ethernet Segment Management
 * 1. Ethernet Segment is a collection of links attached to the same
 *    server (MHD) or switch (MHN)
 * 2. An Ethernet Segment can span multiple PEs and is identified by the
 *    10-byte ES-ID.
 * 3. Local ESs are configured in zebra and sent to BGP
 * 4. Remote ESs are created by BGP when one or more ES-EVIs reference it i.e.
 *    created on first reference and release on last de-reference
 * 5. An ES can be both local and remote. Infact most local ESs are expected
 *    to have an ES peer.
 */

/* A list of remote VTEPs is maintained for each ES. This list includes -
 * 1. VTEPs for which we have imported the ESR i.e. ES-peers
 * 2. VTEPs that have an "active" ES-EVI VTEP i.e. EAD-per-ES and EAD-per-EVI
 *    have been imported into one or more VNIs
 */
static int bgp_evpn_es_vtep_cmp(void *p1, void *p2)
{
        const struct bgp_evpn_es_vtep *es_vtep1 = p1;
        const struct bgp_evpn_es_vtep *es_vtep2 = p2;

        return es_vtep1->vtep_ip.s_addr - es_vtep2->vtep_ip.s_addr;
}

static struct bgp_evpn_es_vtep *bgp_evpn_es_vtep_new(struct bgp_evpn_es *es,
                struct in_addr vtep_ip)
{
        struct bgp_evpn_es_vtep *es_vtep;

        es_vtep = XCALLOC(MTYPE_BGP_EVPN_ES_VTEP, sizeof(*es_vtep));

        es_vtep->es = es;
        es_vtep->vtep_ip.s_addr = vtep_ip.s_addr;
        inet_ntop(AF_INET, &es_vtep->vtep_ip, es_vtep->vtep_str,
                  sizeof(es_vtep->vtep_str));
        listnode_init(&es_vtep->es_listnode, es_vtep);
        listnode_add_sort(es->es_vtep_list, &es_vtep->es_listnode);

        return es_vtep;
}

static void bgp_evpn_es_vtep_free(struct bgp_evpn_es_vtep *es_vtep)
{
        struct bgp_evpn_es *es = es_vtep->es;

        if (CHECK_FLAG(es_vtep->flags, BGP_EVPNES_VTEP_ESR) ||
                        es_vtep->evi_cnt)
                /* as long as there is some reference we can't free it */
                return;

        list_delete_node(es->es_vtep_list, &es_vtep->es_listnode);
        XFREE(MTYPE_BGP_EVPN_ES_VTEP, es_vtep);
}

/* check if VTEP is already part of the list */
static struct bgp_evpn_es_vtep *bgp_evpn_es_vtep_find(struct bgp_evpn_es *es,
                struct in_addr vtep_ip)
{
        struct listnode *node = NULL;
        struct bgp_evpn_es_vtep *es_vtep;

        for (ALL_LIST_ELEMENTS_RO(es->es_vtep_list, node, es_vtep)) {
                if (es_vtep->vtep_ip.s_addr == vtep_ip.s_addr)
                        return es_vtep;
        }
        return NULL;
}

/* Send the remote ES to zebra for NHG programming */
static int bgp_zebra_send_remote_es_vtep(struct bgp *bgp,
                struct bgp_evpn_es_vtep *es_vtep, bool add)
{
        struct bgp_evpn_es *es = es_vtep->es;
        struct stream *s;
        uint32_t flags = 0;

        /* Check socket. */
        if (!zclient || zclient->sock < 0)
                return 0;

        /* Don't try to register if Zebra doesn't know of this instance. */
        if (!IS_BGP_INST_KNOWN_TO_ZEBRA(bgp)) {
                if (BGP_DEBUG(zebra, ZEBRA))
                        zlog_debug("No zebra instance, not installing remote es %s",
                                        es->esi_str);
                return 0;
        }

        if (es_vtep->flags & BGP_EVPNES_VTEP_ESR)
                flags |= ZAPI_ES_VTEP_FLAG_ESR_RXED;

        s = zclient->obuf;
        stream_reset(s);

        zclient_create_header(s,
                add ? ZEBRA_REMOTE_ES_VTEP_ADD : ZEBRA_REMOTE_ES_VTEP_DEL,
                bgp->vrf_id);
        stream_put(s, &es->esi, sizeof(esi_t));
        stream_put_ipv4(s, es_vtep->vtep_ip.s_addr);
        if (add) {
                stream_putl(s, flags);
                stream_putc(s, es_vtep->df_alg);
                stream_putw(s, es_vtep->df_pref);
        }

        stream_putw_at(s, 0, stream_get_endp(s));

        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug("Tx %s Remote ESI %s VTEP %pI4", add ? "ADD" : "DEL",
                           es->esi_str, &es_vtep->vtep_ip);

        frrtrace(3, frr_bgp, evpn_mh_vtep_zsend, add, es, es_vtep);

        return zclient_send_message(zclient);
}

static void bgp_evpn_es_vtep_re_eval_active(struct bgp *bgp,
                                            struct bgp_evpn_es_vtep *es_vtep,
                                            bool param_change)
{
        bool old_active;
        bool new_active;

        old_active = CHECK_FLAG(es_vtep->flags, BGP_EVPNES_VTEP_ACTIVE);
        /* currently we need an active EVI reference to use the VTEP as
         * a nexthop. this may change...
         */
        if (es_vtep->evi_cnt)
                SET_FLAG(es_vtep->flags, BGP_EVPNES_VTEP_ACTIVE);
        else
                UNSET_FLAG(es_vtep->flags, BGP_EVPNES_VTEP_ACTIVE);

        new_active = CHECK_FLAG(es_vtep->flags, BGP_EVPNES_VTEP_ACTIVE);

        if ((old_active != new_active) || (new_active && param_change)) {

                if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                        zlog_debug("es %s vtep %pI4 %s df %u/%u",
                                   es_vtep->es->esi_str, &es_vtep->vtep_ip,
                                   new_active ? "active" : "inactive",
                                   es_vtep->df_alg, es_vtep->df_pref);

                /* send remote ES to zebra */
                bgp_zebra_send_remote_es_vtep(bgp, es_vtep, new_active);

                /* The NHG is updated first for efficient failover handling.
                 * Note the NHG can be de-activated while there are bgp
                 * routes referencing it. Zebra is capable of handling that
                 * elegantly by holding the NHG till all routes using it are
                 * removed.
                 */
                bgp_evpn_l3nhg_update_on_vtep_chg(es_vtep->es);
                /* queue up the es for background consistency checks */
                bgp_evpn_es_cons_checks_pend_add(es_vtep->es);
        }
}

static struct bgp_evpn_es_vtep *bgp_evpn_es_vtep_add(struct bgp *bgp,
                                                     struct bgp_evpn_es *es,
                                                     struct in_addr vtep_ip,
                                                     bool esr, uint8_t df_alg,
                                                     uint16_t df_pref)
{
        struct bgp_evpn_es_vtep *es_vtep;
        bool param_change = false;

        es_vtep = bgp_evpn_es_vtep_find(es, vtep_ip);

        if (!es_vtep)
                es_vtep = bgp_evpn_es_vtep_new(es, vtep_ip);

        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug("es %s vtep %pI4 add %s df %u/%u",
                           es_vtep->es->esi_str, &es_vtep->vtep_ip,
                           esr ? "esr" : "ead", df_alg, df_pref);

        if (esr) {
                SET_FLAG(es_vtep->flags, BGP_EVPNES_VTEP_ESR);
                if ((es_vtep->df_pref != df_pref)
                    || (es_vtep->df_alg != df_alg)) {
                        param_change = true;
                        es_vtep->df_pref = df_pref;
                        es_vtep->df_alg = df_alg;
                }
        } else {
                ++es_vtep->evi_cnt;
        }

        bgp_evpn_es_vtep_re_eval_active(bgp, es_vtep, param_change);

        return es_vtep;
}

static void bgp_evpn_es_vtep_do_del(struct bgp *bgp,
                struct bgp_evpn_es_vtep *es_vtep, bool esr)
{
        bool param_change = false;

        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug("es %s vtep %pI4 del %s", es_vtep->es->esi_str,
                           &es_vtep->vtep_ip, esr ? "esr" : "ead");
        if (esr) {
                UNSET_FLAG(es_vtep->flags, BGP_EVPNES_VTEP_ESR);
                if (es_vtep->df_pref || es_vtep->df_alg) {
                        param_change = true;
                        es_vtep->df_pref = 0;
                        es_vtep->df_alg = 0;
                }
        } else {
                if (es_vtep->evi_cnt)
                        --es_vtep->evi_cnt;
        }

        bgp_evpn_es_vtep_re_eval_active(bgp, es_vtep, param_change);
        bgp_evpn_es_vtep_free(es_vtep);
}

static void bgp_evpn_es_vtep_del(struct bgp *bgp,
                struct bgp_evpn_es *es, struct in_addr vtep_ip, bool esr)
{
        struct bgp_evpn_es_vtep *es_vtep;

        es_vtep = bgp_evpn_es_vtep_find(es, vtep_ip);
        if (es_vtep)
                bgp_evpn_es_vtep_do_del(bgp, es_vtep, esr);
}

/********************** ES MAC-IP paths *************************************
 * 1. Local MAC-IP routes in the VNI routing table are linked to the
 * destination ES (macip_evi_path_list) for efficient updates on ES oper
 * state changes.
 * 2. Non-local MAC-IP routes in the global routing table are linked to
 * the detination for efficient updates on -
 * a. VTEP add/del - this results in a L3NHG update.
 * b. ES-VRF add/del - this may result in the host route being migrated to
 *    L3NHG or vice versa (flat multipath list).
 ****************************************************************************/
static void bgp_evpn_path_es_info_free(struct bgp_path_es_info *es_info)
{
        bgp_evpn_path_es_unlink(es_info);
        XFREE(MTYPE_BGP_EVPN_PATH_ES_INFO, es_info);
}

void bgp_evpn_path_mh_info_free(struct bgp_path_mh_info *mh_info)
{
        if (mh_info->es_info)
                bgp_evpn_path_es_info_free(mh_info->es_info);
        if (mh_info->nh_info)
                bgp_evpn_path_nh_info_free(mh_info->nh_info);
        XFREE(MTYPE_BGP_EVPN_PATH_MH_INFO, mh_info);
}

static struct bgp_path_es_info *
bgp_evpn_path_es_info_new(struct bgp_path_info *pi, vni_t vni)
{
        struct bgp_path_info_extra *e;
        struct bgp_path_mh_info *mh_info;
        struct bgp_path_es_info *es_info;

        e = bgp_path_info_extra_get(pi);

        /* If mh_info doesn't exist allocate it */
        mh_info = e->mh_info;
        if (!mh_info)
                e->mh_info = mh_info = XCALLOC(MTYPE_BGP_EVPN_PATH_MH_INFO,
                                               sizeof(struct bgp_path_mh_info));

        /* If es_info doesn't exist allocate it */
        es_info = mh_info->es_info;
        if (!es_info) {
                mh_info->es_info = es_info =
                        XCALLOC(MTYPE_BGP_EVPN_PATH_ES_INFO,
                                sizeof(struct bgp_path_es_info));
                es_info->vni = vni;
                es_info->pi = pi;
        }

        return es_info;
}

static void bgp_evpn_path_es_unlink(struct bgp_path_es_info *es_info)
{
        struct bgp_evpn_es *es = es_info->es;
        struct bgp_path_info *pi;

        if (!es)
                return;

        pi = es_info->pi;
        if (BGP_DEBUG(evpn_mh, EVPN_MH_RT))
                zlog_debug("vni %u path %pFX unlinked from es %s", es_info->vni,
                           &pi->net->p, es->esi_str);

        if (es_info->vni)
                list_delete_node(es->macip_evi_path_list,
                                 &es_info->es_listnode);
        else
                list_delete_node(es->macip_global_path_list,
                                 &es_info->es_listnode);

        es_info->es = NULL;

        /* if there are no other references against the ES it
         * needs to be freed
         */
        bgp_evpn_es_free(es, __func__);

        /* Note we don't free the path es_info on unlink; it will be freed up
         * along with the path.
         */
}

void bgp_evpn_path_es_link(struct bgp_path_info *pi, vni_t vni, esi_t *esi)
{
        struct bgp_path_es_info *es_info;
        struct bgp_evpn_es *es;
        struct bgp *bgp_evpn;

        es_info = (pi->extra && pi->extra->mh_info)
                          ? pi->extra->mh_info->es_info
                          : NULL;
        /* if the esi is zero just unlink the path from the old es */
        if (!esi || !memcmp(esi, zero_esi, sizeof(*esi))) {
                if (es_info)
                        bgp_evpn_path_es_unlink(es_info);
                return;
        }

        bgp_evpn = bgp_get_evpn();
        if (!bgp_evpn)
                return;

        /* setup es_info against the path if it doesn't aleady exist */
        if (!es_info)
                es_info = bgp_evpn_path_es_info_new(pi, vni);

        /* find-create ES */
        es = bgp_evpn_es_find(esi);
        if (!es)
                es = bgp_evpn_es_new(bgp_evpn, esi);

        /* dup check */
        if (es_info->es == es)
                return;

        /* unlink old ES if any */
        bgp_evpn_path_es_unlink(es_info);

        if (BGP_DEBUG(evpn_mh, EVPN_MH_RT))
                zlog_debug("vni %u path %pFX linked to es %s", vni, &pi->net->p,
                           es->esi_str);

        /* link mac-ip path to the new destination ES */
        es_info->es = es;
        listnode_init(&es_info->es_listnode, es_info);
        if (es_info->vni)
                listnode_add(es->macip_evi_path_list, &es_info->es_listnode);
        else
                listnode_add(es->macip_global_path_list, &es_info->es_listnode);
}

static bool bgp_evpn_is_macip_path(struct bgp_path_info *pi)
{
        struct prefix_evpn *evp;

        /* Only MAC-IP routes need to be linked (MAC-only routes can be
         * skipped) as these lists are maintained for managing
         * host routes in the tenant VRF
         */
        evp = (struct prefix_evpn *)&pi->net->p;
        return is_evpn_prefix_ipaddr_v4(evp) || is_evpn_prefix_ipaddr_v6(evp);
}

/* When a remote ES is added to a VRF, routes using that as
 * a destination need to be migrated to a L3NHG or viceversa.
 * This is done indirectly by re-attempting an install of the
 * route in the associated VRFs. As a part of the VRF install use
 * of l3 NHG is evaluated and this results in the
 * attr.es_flag ATTR_ES_USE_L3_NHG being set or cleared.
 */
static void
bgp_evpn_es_path_update_on_es_vrf_chg(struct bgp_evpn_es_vrf *es_vrf,
                                      const char *reason)
{
        struct listnode *node;
        struct bgp_path_es_info *es_info;
        struct bgp_path_info *pi;
        struct bgp_evpn_es *es = es_vrf->es;

        if (!bgp_mh_info->host_routes_use_l3nhg)
                return;

        if (BGP_DEBUG(evpn_mh, EVPN_MH_RT))
                zlog_debug("update paths linked to es %s on es-vrf %s %s",
                           es->esi_str, es_vrf->bgp_vrf->name, reason);

        for (ALL_LIST_ELEMENTS_RO(es->macip_global_path_list, node, es_info)) {
                pi = es_info->pi;

                if (!bgp_evpn_is_macip_path(pi))
                        continue;

                if (BGP_DEBUG(evpn_mh, EVPN_MH_RT))
                        zlog_debug(
                                "update path %pFX linked to es %s on vrf chg",
                                &pi->net->p, es->esi_str);
                bgp_evpn_route_entry_install_if_vrf_match(es_vrf->bgp_vrf, pi,
                                                          1);
        }
}

static void bgp_evpn_es_frag_free(struct bgp_evpn_es_frag *es_frag)
{
        struct bgp_evpn_es *es = es_frag->es;

        if (es->es_base_frag == es_frag)
                es->es_base_frag = NULL;

        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug("es %s frag %u free", es->esi_str, es_frag->rd_id);
        list_delete_node(es->es_frag_list, &es_frag->es_listnode);

        /* EVIs that are advertised using the info in this fragment */
        list_delete(&es_frag->es_evi_frag_list);

        bf_release_index(bm->rd_idspace, es_frag->rd_id);


        XFREE(MTYPE_BGP_EVPN_ES_FRAG, es_frag);
}

static void bgp_evpn_es_frag_free_unused(struct bgp_evpn_es_frag *es_frag)
{
        if ((es_frag->es->es_base_frag == es_frag) ||
            listcount(es_frag->es_evi_frag_list))
                return;

        bgp_evpn_es_frag_free(es_frag);
}

static void bgp_evpn_es_frag_free_all(struct bgp_evpn_es *es)
{
        struct listnode *node;
        struct listnode *nnode;
        struct bgp_evpn_es_frag *es_frag;

        for (ALL_LIST_ELEMENTS(es->es_frag_list, node, nnode, es_frag))
                bgp_evpn_es_frag_free(es_frag);
}

static struct bgp_evpn_es_frag *bgp_evpn_es_frag_new(struct bgp_evpn_es *es)
{
        struct bgp_evpn_es_frag *es_frag;
        char buf[BGP_EVPN_PREFIX_RD_LEN];
        struct bgp *bgp;

        es_frag = XCALLOC(MTYPE_BGP_EVPN_ES_FRAG, sizeof(*es_frag));
        bf_assign_index(bm->rd_idspace, es_frag->rd_id);
        es_frag->prd.family = AF_UNSPEC;
        es_frag->prd.prefixlen = 64;
        bgp = bgp_get_evpn();
        snprintfrr(buf, sizeof(buf), "%pI4:%hu", &bgp->router_id,
                   es_frag->rd_id);
        (void)str2prefix_rd(buf, &es_frag->prd);

        /* EVIs that are advertised using the info in this fragment */
        es_frag->es_evi_frag_list = list_new();
        listset_app_node_mem(es_frag->es_evi_frag_list);

        /* Link the fragment to the parent ES */
        es_frag->es = es;
        listnode_init(&es_frag->es_listnode, es_frag);
        listnode_add(es->es_frag_list, &es_frag->es_listnode);

        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug("es %s frag %u new", es->esi_str, es_frag->rd_id);
        return es_frag;
}

static struct bgp_evpn_es_frag *
bgp_evpn_es_find_frag_with_space(struct bgp_evpn_es *es)
{
        struct listnode *node;
        struct bgp_evpn_es_frag *es_frag;

        for (ALL_LIST_ELEMENTS_RO(es->es_frag_list, node, es_frag)) {
                if (listcount(es_frag->es_evi_frag_list) <
                    bgp_mh_info->evi_per_es_frag)
                        return es_frag;
        }

        /* No frags where found with space; allocate a new one */
        return bgp_evpn_es_frag_new(es);
}

/* Link the ES-EVI to one of the ES fragments */
static void bgp_evpn_es_frag_evi_add(struct bgp_evpn_es_evi *es_evi)
{
        struct bgp_evpn_es_frag *es_frag;
        struct bgp_evpn_es *es = es_evi->es;

        if (es_evi->es_frag ||
            !(CHECK_FLAG(es_evi->flags, BGP_EVPNES_EVI_LOCAL)))
                return;

        es_frag = bgp_evpn_es_find_frag_with_space(es);

        es_evi->es_frag = es_frag;
        listnode_init(&es_evi->es_frag_listnode, es_evi);
        listnode_add(es_frag->es_evi_frag_list, &es_evi->es_frag_listnode);

        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug("es %s vni %d linked to frag %u", es->esi_str,
                           es_evi->vpn->vni, es_frag->rd_id);
}

/* UnLink the ES-EVI from the ES fragment */
static void bgp_evpn_es_frag_evi_del(struct bgp_evpn_es_evi *es_evi,
                                     bool send_ead_del_if_empty)
{
        struct bgp_evpn_es_frag *es_frag = es_evi->es_frag;
        struct prefix_evpn p;
        struct bgp_evpn_es *es;
        struct bgp *bgp;

        if (!es_frag)
                return;

        es = es_frag->es;
        es_evi->es_frag = NULL;
        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug("es %s vni %d unlinked from frag %u", es->esi_str,
                           es_evi->vpn->vni, es_frag->rd_id);

        list_delete_node(es_frag->es_evi_frag_list, &es_evi->es_frag_listnode);

        /*
         * if there are no other EVIs on the fragment deleted the EAD-ES for
         * the fragment
         */
        if (send_ead_del_if_empty && !listcount(es_frag->es_evi_frag_list)) {
                bgp = bgp_get_evpn();

                if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                        zlog_debug("es %s frag %u ead-es route delete",
                                   es->esi_str, es_frag->rd_id);
                build_evpn_type1_prefix(&p, BGP_EVPN_AD_ES_ETH_TAG, &es->esi,
                                        es->originator_ip);
                p.prefix.ead_addr.frag_id = es_frag->rd_id;
                bgp_evpn_mh_route_delete(bgp, es, NULL, es_frag, &p);
        }

        /* We don't attempt to coalesce frags that may not be full. Instead we
         * only free up the frag when it is completely empty.
         */
        bgp_evpn_es_frag_free_unused(es_frag);
}

/* Link the ES-EVIs to one of the ES fragments */
static void bgp_evpn_es_frag_evi_update_all(struct bgp_evpn_es *es, bool add)
{
        struct listnode *node;
        struct bgp_evpn_es_evi *es_evi;

        for (ALL_LIST_ELEMENTS_RO(es->es_evi_list, node, es_evi)) {
                if (add)
                        bgp_evpn_es_frag_evi_add(es_evi);
                else
                        bgp_evpn_es_frag_evi_del(es_evi, false);
        }
}

/* compare ES-IDs for the global ES RB tree */
static int bgp_es_rb_cmp(const struct bgp_evpn_es *es1,
                const struct bgp_evpn_es *es2)
{
        return memcmp(&es1->esi, &es2->esi, ESI_BYTES);
}
RB_GENERATE(bgp_es_rb_head, bgp_evpn_es, rb_node, bgp_es_rb_cmp);

struct bgp_evpn_es *bgp_evpn_es_find(const esi_t *esi)
{
        struct bgp_evpn_es tmp;

        memcpy(&tmp.esi, esi, sizeof(esi_t));
        return RB_FIND(bgp_es_rb_head, &bgp_mh_info->es_rb_tree, &tmp);
}

static struct bgp_evpn_es *bgp_evpn_es_new(struct bgp *bgp, const esi_t *esi)
{
        struct bgp_evpn_es *es;

        if (!bgp)
                return NULL;

        es = XCALLOC(MTYPE_BGP_EVPN_ES, sizeof(struct bgp_evpn_es));

        /* set the ESI */
        memcpy(&es->esi, esi, sizeof(esi_t));

        /* Initialise the VTEP list */
        es->es_vtep_list = list_new();
        listset_app_node_mem(es->es_vtep_list);
        es->es_vtep_list->cmp = bgp_evpn_es_vtep_cmp;

        esi_to_str(&es->esi, es->esi_str, sizeof(es->esi_str));

        /* Initialize the ES routing table */
        es->route_table = bgp_table_init(bgp, AFI_L2VPN, SAFI_EVPN);

        /* Add to rb_tree */
        RB_INSERT(bgp_es_rb_head, &bgp_mh_info->es_rb_tree, es);

        /* Initialise the ES-EVI list */
        es->es_evi_list = list_new();
        listset_app_node_mem(es->es_evi_list);

        /* Initialise the ES-VRF list used for L3NHG management */
        es->es_vrf_list = list_new();
        listset_app_node_mem(es->es_vrf_list);

        /* Initialise the route list used for efficient event handling */
        es->macip_evi_path_list = list_new();
        listset_app_node_mem(es->macip_evi_path_list);
        es->macip_global_path_list = list_new();
        listset_app_node_mem(es->macip_global_path_list);
        es->es_frag_list = list_new();
        listset_app_node_mem(es->es_frag_list);

        QOBJ_REG(es, bgp_evpn_es);

        return es;
}

/* Free a given ES -
 * This just frees appropriate memory, caller should have taken other
 * needed actions.
 */
static void bgp_evpn_es_free(struct bgp_evpn_es *es, const char *caller)
{
        if ((es->flags & (BGP_EVPNES_LOCAL | BGP_EVPNES_REMOTE))
            || listcount(es->macip_evi_path_list)
            || listcount(es->macip_global_path_list))
                return;

        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug("%s: es %s free", caller, es->esi_str);

        /* cleanup resources maintained against the ES */
        list_delete(&es->es_evi_list);
        list_delete(&es->es_vrf_list);
        list_delete(&es->es_vtep_list);
        list_delete(&es->macip_evi_path_list);
        list_delete(&es->macip_global_path_list);
        list_delete(&es->es_frag_list);
        bgp_table_unlock(es->route_table);

        /* remove the entry from various databases */
        RB_REMOVE(bgp_es_rb_head, &bgp_mh_info->es_rb_tree, es);
        bgp_evpn_es_cons_checks_pend_del(es);

        QOBJ_UNREG(es);
        XFREE(MTYPE_BGP_EVPN_ES, es);
}

static inline bool bgp_evpn_is_es_local_and_non_bypass(struct bgp_evpn_es *es)
{
        return (es->flags & BGP_EVPNES_LOCAL)
               && !(es->flags & BGP_EVPNES_BYPASS);
}

/* init local info associated with the ES */
static void bgp_evpn_es_local_info_set(struct bgp *bgp, struct bgp_evpn_es *es)
{
        bool old_is_local;
        bool is_local;

        if (CHECK_FLAG(es->flags, BGP_EVPNES_LOCAL))
                return;

        old_is_local = bgp_evpn_is_es_local_and_non_bypass(es);
        SET_FLAG(es->flags, BGP_EVPNES_LOCAL);

        listnode_init(&es->es_listnode, es);
        listnode_add(bgp_mh_info->local_es_list, &es->es_listnode);

        /* setup the first ES fragment; more fragments may be allocated based
         * on the the number of EVI entries
         */
        es->es_base_frag = bgp_evpn_es_frag_new(es);
        /* distribute ES-EVIs to one or more ES fragments */
        bgp_evpn_es_frag_evi_update_all(es, true);

        is_local = bgp_evpn_is_es_local_and_non_bypass(es);
        if (old_is_local != is_local)
                bgp_evpn_mac_update_on_es_local_chg(es, is_local);
}

/* clear any local info associated with the ES */
static void bgp_evpn_es_local_info_clear(struct bgp_evpn_es *es, bool finish)
{
        bool old_is_local;
        bool is_local;

        if (!CHECK_FLAG(es->flags, BGP_EVPNES_LOCAL))
                return;

        /* clear the es frag references and free them up */
        bgp_evpn_es_frag_evi_update_all(es, false);
        es->es_base_frag = NULL;
        bgp_evpn_es_frag_free_all(es);

        old_is_local = bgp_evpn_is_es_local_and_non_bypass(es);
        UNSET_FLAG(es->flags, BGP_EVPNES_LOCAL);

        is_local = bgp_evpn_is_es_local_and_non_bypass(es);
        if (!finish && (old_is_local != is_local))
                bgp_evpn_mac_update_on_es_local_chg(es, is_local);

        /* remove from the ES local list */
        list_delete_node(bgp_mh_info->local_es_list, &es->es_listnode);

        bgp_evpn_es_free(es, __func__);
}

/* eval remote info associated with the ES */
static void bgp_evpn_es_remote_info_re_eval(struct bgp_evpn_es *es)
{
        if (es->remote_es_evi_cnt) {
                SET_FLAG(es->flags, BGP_EVPNES_REMOTE);
        } else {
                if (CHECK_FLAG(es->flags, BGP_EVPNES_REMOTE)) {
                        UNSET_FLAG(es->flags, BGP_EVPNES_REMOTE);
                        bgp_evpn_es_free(es, __func__);
                }
        }
}

/* If ES is present and local it needs to be active/oper-up for
 * including L3 EC
 */
bool bgp_evpn_es_add_l3_ecomm_ok(esi_t *esi)
{
        struct bgp_evpn_es *es;

        if (!esi || !bgp_mh_info->suppress_l3_ecomm_on_inactive_es)
                return true;

        es = bgp_evpn_es_find(esi);

        return (!es || !(es->flags & BGP_EVPNES_LOCAL)
                || bgp_evpn_local_es_is_active(es));
}

static bool bgp_evpn_is_valid_local_path(struct bgp_path_info *pi)
{
        return (CHECK_FLAG(pi->flags, BGP_PATH_VALID)
                && pi->type == ZEBRA_ROUTE_BGP
                && pi->sub_type == BGP_ROUTE_STATIC);
}

/* Update all local MAC-IP routes in the VNI routing table associated
 * with the ES. When the ES is down the routes are advertised without
 * the L3 extcomm
 */
static void bgp_evpn_mac_update_on_es_oper_chg(struct bgp_evpn_es *es)
{
        struct listnode *node;
        struct bgp_path_es_info *es_info;
        struct bgp_path_info *pi;
        struct bgp *bgp;
        struct bgpevpn *vpn;

        if (!bgp_mh_info->suppress_l3_ecomm_on_inactive_es)
                return;

        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug("update paths linked to es %s on oper chg",
                           es->esi_str);

        bgp = bgp_get_evpn();
        for (ALL_LIST_ELEMENTS_RO(es->macip_evi_path_list, node, es_info)) {
                pi = es_info->pi;

                if (!bgp_evpn_is_valid_local_path(pi))
                        continue;

                if (!bgp_evpn_is_macip_path(pi))
                        continue;

                vpn = bgp_evpn_lookup_vni(bgp, es_info->vni);
                if (!vpn)
                        continue;

                if (BGP_DEBUG(evpn_mh, EVPN_MH_RT))
                        zlog_debug(
                                "update path %d %pFX linked to es %s on oper chg",
                                es_info->vni, &pi->net->p, es->esi_str);

                bgp_evpn_update_type2_route_entry(bgp, vpn, pi->net, pi,
                                                  __func__);
        }
}

static bool bgp_evpn_is_valid_bgp_path(struct bgp_path_info *pi)
{
        return (CHECK_FLAG(pi->flags, BGP_PATH_VALID)
                && pi->type == ZEBRA_ROUTE_BGP
                && pi->sub_type == BGP_ROUTE_NORMAL);
}

/* If an ES is no longer local (or becomes local) we need to re-install
 * paths using that ES as destination. This is needed as the criteria
 * for best path selection has changed.
 */
static void bgp_evpn_mac_update_on_es_local_chg(struct bgp_evpn_es *es,
                                                bool is_local)
{
        struct listnode *node;
        struct bgp_path_es_info *es_info;
        struct bgp_path_info *pi;
        bool tmp_local;
        struct attr *attr_new;
        struct attr attr_tmp;

        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug("update paths linked to es %s on chg to %s",
                           es->esi_str, is_local ? "local" : "non-local");

        for (ALL_LIST_ELEMENTS_RO(es->macip_global_path_list, node, es_info)) {
                pi = es_info->pi;

                /* Consider "valid" remote routes */
                if (!bgp_evpn_is_valid_bgp_path(pi))
                        continue;

                if (!pi->attr)
                        continue;

                tmp_local = !!(pi->attr->es_flags & ATTR_ES_IS_LOCAL);
                if (tmp_local == is_local)
                        continue;

                if (BGP_DEBUG(evpn_mh, EVPN_MH_RT))
                        zlog_debug(
                                "update path %pFX linked to es %s on chg to %s",
                                &pi->net->p, es->esi_str,
                                is_local ? "local" : "non-local");

                attr_tmp = *pi->attr;
                if (is_local)
                        attr_tmp.es_flags |= ATTR_ES_IS_LOCAL;
                else
                        attr_tmp.es_flags &= ~ATTR_ES_IS_LOCAL;
                attr_new = bgp_attr_intern(&attr_tmp);
                bgp_attr_unintern(&pi->attr);
                pi->attr = attr_new;
                bgp_evpn_import_type2_route(pi, 1);
        }
}

static void bgp_evpn_local_es_deactivate(struct bgp *bgp,
                                         struct bgp_evpn_es *es)
{
        struct prefix_evpn p;
        int ret;

        /* withdraw ESR */
        /* Delete and withdraw locally learnt ES route */
        build_evpn_type4_prefix(&p, &es->esi, es->originator_ip);
        ret = bgp_evpn_type4_route_delete(bgp, es, &p);
        if (ret) {
                flog_err(EC_BGP_EVPN_ROUTE_DELETE,
                                "%u failed to delete type-4 route for ESI %s",
                                bgp->vrf_id, es->esi_str);
        }

        /* withdraw EAD-EVI */
        if (!bgp_mh_info->ead_evi_adv_for_down_links)
                bgp_evpn_local_type1_evi_route_del(bgp, es);

        /* withdraw EAD-ES */
        bgp_evpn_ead_es_route_delete(bgp, es);

        bgp_evpn_mac_update_on_es_oper_chg(es);
}

/* Process ES link oper-down by withdrawing ES-EAD and ESR */
static void bgp_evpn_local_es_down(struct bgp *bgp, struct bgp_evpn_es *es)
{
        bool old_active;

        if (!CHECK_FLAG(es->flags, BGP_EVPNES_OPER_UP))
                return;

        old_active = bgp_evpn_local_es_is_active(es);
        UNSET_FLAG(es->flags, BGP_EVPNES_OPER_UP);

        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug("local es %s down", es->esi_str);

        if (old_active)
                bgp_evpn_local_es_deactivate(bgp, es);
}

static void bgp_evpn_local_es_activate(struct bgp *bgp, struct bgp_evpn_es *es,
                                       bool regen_ead, bool regen_esr)
{
        struct prefix_evpn p;

        if (regen_esr) {
                if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                        zlog_debug("local es %s generate ESR", es->esi_str);
                /* generate ESR */
                build_evpn_type4_prefix(&p, &es->esi, es->originator_ip);
                if (bgp_evpn_type4_route_update(bgp, es, &p))
                        flog_err(EC_BGP_EVPN_ROUTE_CREATE,
                                 "%u: Type4 route creation failure for ESI %s",
                                 bgp->vrf_id, es->esi_str);
        }

        if (regen_ead) {
                if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                        zlog_debug("local es %s generate EAD", es->esi_str);
                /* generate EAD-EVI */
                bgp_evpn_local_type1_evi_route_add(bgp, es);

                /* generate EAD-ES */
                bgp_evpn_ead_es_route_update(bgp, es);
        }

        bgp_evpn_mac_update_on_es_oper_chg(es);
}

/* Process ES link oper-up by generating ES-EAD and ESR */
static void bgp_evpn_local_es_up(struct bgp *bgp, struct bgp_evpn_es *es,
                                 bool regen_esr)
{
        bool regen_ead = false;
        bool active = false;

        if (!CHECK_FLAG(es->flags, BGP_EVPNES_OPER_UP)) {
                if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                        zlog_debug("local es %s up", es->esi_str);

                SET_FLAG(es->flags, BGP_EVPNES_OPER_UP);
                regen_esr = true;
                regen_ead = true;
        }

        active = bgp_evpn_local_es_is_active(es);
        if (active && (regen_ead || regen_esr))
                bgp_evpn_local_es_activate(bgp, es, regen_ead, regen_esr);
}

/* If an ethernet segment is in LACP bypass we cannot advertise
 * reachability to it i.e. EAD-per-ES and ESR is not advertised in
 * bypass state.
 * PS: EAD-per-EVI will continue to be advertised
 */
static void bgp_evpn_local_es_bypass_update(struct bgp *bgp,
                                            struct bgp_evpn_es *es, bool bypass)
{
        bool old_bypass = !!(es->flags & BGP_EVPNES_BYPASS);
        bool old_active;
        bool new_active;
        bool old_is_local;
        bool is_local;

        if (bypass == old_bypass)
                return;

        old_active = bgp_evpn_local_es_is_active(es);
        old_is_local = bgp_evpn_is_es_local_and_non_bypass(es);
        if (bypass)
                SET_FLAG(es->flags, BGP_EVPNES_BYPASS);
        else
                UNSET_FLAG(es->flags, BGP_EVPNES_BYPASS);

        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug("local es %s bypass %s", es->esi_str,
                           bypass ? "set" : "clear");

        new_active = bgp_evpn_local_es_is_active(es);
        if (old_active != new_active) {
                if (new_active)
                        bgp_evpn_local_es_activate(bgp, es, true, true);
                else
                        bgp_evpn_local_es_deactivate(bgp, es);
        }

        is_local = bgp_evpn_is_es_local_and_non_bypass(es);
        if (old_is_local != is_local)
                bgp_evpn_mac_update_on_es_local_chg(es, is_local);
}

static void bgp_evpn_local_es_do_del(struct bgp *bgp, struct bgp_evpn_es *es)
{
        struct bgp_evpn_es_evi *es_evi;
        struct listnode *evi_node, *evi_next_node;

        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug("del local es %s", es->esi_str);

        /* Delete all local EVPN ES routes from ESI table
         * and schedule for processing (to withdraw from peers))
         */
        bgp_evpn_es_route_del_all(bgp, es);

        /* release all local ES EVIs associated with the ES */
        for (ALL_LIST_ELEMENTS(es->es_evi_list, evi_node,
                                evi_next_node, es_evi)) {
                bgp_evpn_local_es_evi_do_del(es_evi);
        }

        /* Clear local info associated with the ES and free it up if there is
         * no remote reference
         */
        bgp_evpn_es_local_info_clear(es, false);
}

bool bgp_evpn_is_esi_local_and_non_bypass(esi_t *esi)
{
        struct bgp_evpn_es *es = NULL;

        /* Lookup ESI hash - should exist. */
        es = bgp_evpn_es_find(esi);

        return es && bgp_evpn_is_es_local_and_non_bypass(es);
}

int bgp_evpn_local_es_del(struct bgp *bgp, esi_t *esi)
{
        struct bgp_evpn_es *es = NULL;

        /* Lookup ESI hash - should exist. */
        es = bgp_evpn_es_find(esi);
        if (!es) {
                flog_warn(EC_BGP_EVPN_ESI, "%u: ES missing at local ES DEL",
                          bgp->vrf_id);
                return -1;
        }

        bgp_evpn_local_es_do_del(bgp, es);
        return 0;
}

/* Handle device to ES id association. Results in the creation of a local
 * ES.
 */
int bgp_evpn_local_es_add(struct bgp *bgp, esi_t *esi,
                          struct in_addr originator_ip, bool oper_up,
                          uint16_t df_pref, bool bypass)
{
        char buf[ESI_STR_LEN];
        struct bgp_evpn_es *es;
        bool new_es = true;
        bool regen_esr = false;

        /* create the new es */
        es = bgp_evpn_es_find(esi);
        if (es) {
                if (CHECK_FLAG(es->flags, BGP_EVPNES_LOCAL))
                        new_es = false;
        } else {
                es = bgp_evpn_es_new(bgp, esi);
                if (!es) {
                        flog_err(EC_BGP_ES_CREATE,
                                "%u: Failed to allocate ES entry for ESI %s - at Local ES Add",
                                bgp->vrf_id, esi_to_str(esi, buf, sizeof(buf)));
                        return -1;
                }
        }

        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug("add local es %s orig-ip %pI4 df_pref %u %s",
                           es->esi_str, &originator_ip, df_pref,
                           bypass ? "bypass" : "");

        es->originator_ip = originator_ip;
        if (df_pref != es->df_pref) {
                es->df_pref = df_pref;
                regen_esr = true;
        }
        bgp_evpn_es_local_info_set(bgp, es);

        /* import all remote Type-4 routes in the ES table */
        if (new_es)
                bgp_evpn_type4_remote_routes_import(bgp, es,
                                true /* install */);

        /* create and advertise EAD-EVI routes for the ES -
         * XXX - till an ES-EVI reference is created there is really nothing to
         * advertise
         */
        if (bgp_mh_info->ead_evi_adv_for_down_links)
                bgp_evpn_local_type1_evi_route_add(bgp, es);

        bgp_evpn_local_es_bypass_update(bgp, es, bypass);

        /* If the ES link is operationally up generate EAD-ES. EAD-EVI
         * can be generated even if the link is inactive.
         */
        if (oper_up)
                bgp_evpn_local_es_up(bgp, es, regen_esr);
        else
                bgp_evpn_local_es_down(bgp, es);

        return 0;
}

static void bgp_evpn_es_json_frag_fill(json_object *json_frags,
                                       struct bgp_evpn_es *es)
{
        json_object *json_frag;
        char buf1[RD_ADDRSTRLEN];
        struct listnode *node;
        struct bgp_evpn_es_frag *es_frag;

        for (ALL_LIST_ELEMENTS_RO(es->es_frag_list, node, es_frag)) {
                json_frag = json_object_new_object();

                json_object_string_add(
                        json_frag, "rd",
                        prefix_rd2str(&es_frag->prd, buf1, sizeof(buf1)));
                json_object_int_add(json_frag, "eviCount",
                                    listcount(es_frag->es_evi_frag_list));

                json_object_array_add(json_frags, json_frag);
        }
}

static void bgp_evpn_es_frag_show_detail(struct vty *vty,
                                         struct bgp_evpn_es *es)
{
        struct listnode *node;
        char buf1[RD_ADDRSTRLEN];
        struct bgp_evpn_es_frag *es_frag;

        for (ALL_LIST_ELEMENTS_RO(es->es_frag_list, node, es_frag)) {
                vty_out(vty, "  %s EVIs: %d\n",
                        prefix_rd2str(&es_frag->prd, buf1, sizeof(buf1)),
                        listcount(es_frag->es_evi_frag_list));
        }
}

static char *bgp_evpn_es_vteps_str(char *vtep_str, struct bgp_evpn_es *es,
                                   uint8_t vtep_str_size)
{
        char vtep_flag_str[BGP_EVPN_FLAG_STR_SZ];
        struct listnode *node;
        struct bgp_evpn_es_vtep *es_vtep;
        bool first = true;
        char ip_buf[INET6_ADDRSTRLEN];

        vtep_str[0] = '\0';
        for (ALL_LIST_ELEMENTS_RO(es->es_vtep_list, node, es_vtep)) {
                vtep_flag_str[0] = '\0';

                if (es_vtep->flags & BGP_EVPNES_VTEP_ESR)
                        strlcat(vtep_flag_str, "E", sizeof(vtep_flag_str));
                if (es_vtep->flags & BGP_EVPNES_VTEP_ACTIVE)
                        strlcat(vtep_flag_str, "A", sizeof(vtep_flag_str));

                if (!strlen(vtep_flag_str))
                        strlcat(vtep_flag_str, "-", sizeof(vtep_flag_str));
                if (first)
                        first = false;
                else
                        strlcat(vtep_str, ",", vtep_str_size);
                strlcat(vtep_str,
                        inet_ntop(AF_INET, &es_vtep->vtep_ip, ip_buf,
                                  sizeof(ip_buf)),
                        vtep_str_size);
                strlcat(vtep_str, "(", vtep_str_size);
                strlcat(vtep_str, vtep_flag_str, vtep_str_size);
                strlcat(vtep_str, ")", vtep_str_size);
        }

        return vtep_str;
}

static void bgp_evpn_es_json_vtep_fill(json_object *json_vteps,
                struct bgp_evpn_es_vtep *es_vtep)
{
        json_object *json_vtep_entry;
        json_object *json_flags;

        json_vtep_entry = json_object_new_object();

        json_object_string_addf(json_vtep_entry, "vtep_ip", "%pI4",
                                &es_vtep->vtep_ip);
        if (es_vtep->flags & (BGP_EVPNES_VTEP_ESR |
                         BGP_EVPNES_VTEP_ACTIVE)) {
                json_flags = json_object_new_array();
                if (es_vtep->flags & BGP_EVPNES_VTEP_ESR)
                        json_array_string_add(json_flags, "esr");
                if (es_vtep->flags & BGP_EVPNES_VTEP_ACTIVE)
                        json_array_string_add(json_flags, "active");
                json_object_object_add(json_vtep_entry, "flags", json_flags);
                if (es_vtep->flags & BGP_EVPNES_VTEP_ESR) {
                        json_object_int_add(json_vtep_entry, "dfPreference",
                                            es_vtep->df_pref);
                        json_object_int_add(json_vtep_entry, "dfAlgorithm",
                                            es_vtep->df_pref);
                }
        }

        json_object_array_add(json_vteps,
                        json_vtep_entry);
}

static void bgp_evpn_es_vteps_show_detail(struct vty *vty,
                                          struct bgp_evpn_es *es)
{
        char vtep_flag_str[BGP_EVPN_FLAG_STR_SZ];
        struct listnode *node;
        struct bgp_evpn_es_vtep *es_vtep;
        char alg_buf[EVPN_DF_ALG_STR_LEN];

        for (ALL_LIST_ELEMENTS_RO(es->es_vtep_list, node, es_vtep)) {
                vtep_flag_str[0] = '\0';
                if (es_vtep->flags & BGP_EVPNES_VTEP_ESR)
                        strlcat(vtep_flag_str, "E", sizeof(vtep_flag_str));
                if (es_vtep->flags & BGP_EVPNES_VTEP_ACTIVE)
                        strlcat(vtep_flag_str, "A", sizeof(vtep_flag_str));

                if (!strlen(vtep_flag_str))
                        strlcat(vtep_flag_str, "-", sizeof(vtep_flag_str));

                vty_out(vty, "  %pI4 flags: %s", &es_vtep->vtep_ip,
                        vtep_flag_str);

                if (es_vtep->flags & BGP_EVPNES_VTEP_ESR)
                        vty_out(vty, " df_alg: %s df_pref: %u\n",
                                evpn_es_df_alg2str(es_vtep->df_alg, alg_buf,
                                                   sizeof(alg_buf)),
                                es_vtep->df_pref);
                else
                        vty_out(vty, "\n");
        }
}

static void bgp_evpn_es_show_entry(struct vty *vty,
                struct bgp_evpn_es *es, json_object *json)
{
        char buf1[RD_ADDRSTRLEN];
        struct listnode *node;
        struct bgp_evpn_es_vtep *es_vtep;

        if (json) {
                json_object *json_vteps;
                json_object *json_types;

                json_object_string_add(json, "esi", es->esi_str);
                if (es->es_base_frag)
                        json_object_string_add(
                                json, "rd",
                                prefix_rd2str(&es->es_base_frag->prd, buf1,
                                              sizeof(buf1)));

                if (es->flags & (BGP_EVPNES_LOCAL | BGP_EVPNES_REMOTE)) {
                        json_types = json_object_new_array();
                        if (es->flags & BGP_EVPNES_LOCAL)
                                json_array_string_add(json_types, "local");
                        if (es->flags & BGP_EVPNES_REMOTE)
                                json_array_string_add(json_types, "remote");
                        json_object_object_add(json, "type", json_types);
                }

                if (listcount(es->es_vtep_list)) {
                        json_vteps = json_object_new_array();
                        for (ALL_LIST_ELEMENTS_RO(es->es_vtep_list,
                                                node, es_vtep)) {
                                bgp_evpn_es_json_vtep_fill(json_vteps, es_vtep);
                        }
                        json_object_object_add(json, "vteps", json_vteps);
                }
                json_object_int_add(json, "vniCount",
                                listcount(es->es_evi_list));
        } else {
                char type_str[4];
                char vtep_str[ES_VTEP_LIST_STR_SZ + BGP_EVPN_VTEPS_FLAG_STR_SZ];

                type_str[0] = '\0';
                if (es->flags & BGP_EVPNES_BYPASS)
                        strlcat(type_str, "B", sizeof(type_str));
                if (es->flags & BGP_EVPNES_LOCAL)
                        strlcat(type_str, "L", sizeof(type_str));
                if (es->flags & BGP_EVPNES_REMOTE)
                        strlcat(type_str, "R", sizeof(type_str));
                if (es->inconsistencies)
                        strlcat(type_str, "I", sizeof(type_str));

                bgp_evpn_es_vteps_str(vtep_str, es, sizeof(vtep_str));

                if (es->es_base_frag)
                        prefix_rd2str(&es->es_base_frag->prd, buf1,
                                      sizeof(buf1));
                else
                        strlcpy(buf1, "-", sizeof(buf1));

                vty_out(vty, "%-30s %-5s %-21s %-8d %s\n",
                                es->esi_str, type_str, buf1,
                                listcount(es->es_evi_list), vtep_str);
        }
}

static void bgp_evpn_es_show_entry_detail(struct vty *vty,
                struct bgp_evpn_es *es, json_object *json)
{
        if (json) {
                json_object *json_flags;
                json_object *json_incons;
                json_object *json_vteps;
                json_object *json_frags;
                struct listnode *node;
                struct bgp_evpn_es_vtep *es_vtep;

                /* Add the "brief" info first */
                bgp_evpn_es_show_entry(vty, es, json);
                if (es->flags
                    & (BGP_EVPNES_OPER_UP | BGP_EVPNES_ADV_EVI
                       | BGP_EVPNES_BYPASS)) {
                        json_flags = json_object_new_array();
                        if (es->flags & BGP_EVPNES_OPER_UP)
                                json_array_string_add(json_flags, "up");
                        if (es->flags & BGP_EVPNES_ADV_EVI)
                                json_array_string_add(json_flags,
                                                "advertiseEVI");
                        if (es->flags & BGP_EVPNES_BYPASS)
                                json_array_string_add(json_flags, "bypass");
                        json_object_object_add(json, "flags", json_flags);
                }
                json_object_string_addf(json, "originator_ip", "%pI4",
                                        &es->originator_ip);
                json_object_int_add(json, "remoteVniCount",
                                es->remote_es_evi_cnt);
                json_object_int_add(json, "vrfCount",
                                    listcount(es->es_vrf_list));
                json_object_int_add(json, "macipPathCount",
                                    listcount(es->macip_evi_path_list));
                json_object_int_add(json, "macipGlobalPathCount",
                                    listcount(es->macip_global_path_list));
                json_object_int_add(json, "inconsistentVniVtepCount",
                                es->incons_evi_vtep_cnt);
                if (listcount(es->es_vtep_list)) {
                        json_vteps = json_object_new_array();
                        for (ALL_LIST_ELEMENTS_RO(es->es_vtep_list, node,
                                                  es_vtep)) {
                                bgp_evpn_es_json_vtep_fill(json_vteps, es_vtep);
                        }
                        json_object_object_add(json, "vteps", json_vteps);
                }
                if (listcount(es->es_frag_list)) {
                        json_frags = json_object_new_array();
                        bgp_evpn_es_json_frag_fill(json_frags, es);
                        json_object_object_add(json, "fragments", json_frags);
                }
                if (es->inconsistencies) {
                        json_incons = json_object_new_array();
                        if (es->inconsistencies & BGP_EVPNES_INCONS_VTEP_LIST)
                                json_array_string_add(json_incons,
                                                "vni-vtep-mismatch");
                        json_object_object_add(json, "inconsistencies",
                                        json_incons);
                }
        } else {
                char incons_str[BGP_EVPNES_INCONS_STR_SZ];
                char type_str[4];
                char buf1[RD_ADDRSTRLEN];

                type_str[0] = '\0';
                if (es->flags & BGP_EVPNES_LOCAL)
                        strlcat(type_str, "L", sizeof(type_str));
                if (es->flags & BGP_EVPNES_REMOTE)
                        strlcat(type_str, "R", sizeof(type_str));

                if (es->es_base_frag)
                        prefix_rd2str(&es->es_base_frag->prd, buf1,
                                      sizeof(buf1));
                else
                        strlcpy(buf1, "-", sizeof(buf1));

                vty_out(vty, "ESI: %s\n", es->esi_str);
                vty_out(vty, " Type: %s\n", type_str);
                vty_out(vty, " RD: %s\n", buf1);
                vty_out(vty, " Originator-IP: %pI4\n", &es->originator_ip);
                if (es->flags & BGP_EVPNES_LOCAL)
                        vty_out(vty, " Local ES DF preference: %u\n",
                                es->df_pref);
                if (es->flags & BGP_EVPNES_BYPASS)
                        vty_out(vty, " LACP bypass: on\n");
                vty_out(vty, " VNI Count: %d\n", listcount(es->es_evi_list));
                vty_out(vty, " Remote VNI Count: %d\n",
                                es->remote_es_evi_cnt);
                vty_out(vty, " VRF Count: %d\n", listcount(es->es_vrf_list));
                vty_out(vty, " MACIP EVI Path Count: %d\n",
                        listcount(es->macip_evi_path_list));
                vty_out(vty, " MACIP Global Path Count: %d\n",
                        listcount(es->macip_global_path_list));
                vty_out(vty, " Inconsistent VNI VTEP Count: %d\n",
                                es->incons_evi_vtep_cnt);
                if (es->inconsistencies) {
                        incons_str[0] = '\0';
                        if (es->inconsistencies & BGP_EVPNES_INCONS_VTEP_LIST)
                                strlcat(incons_str, "vni-vtep-mismatch",
                                        sizeof(incons_str));
                } else {
                        strlcpy(incons_str, "-", sizeof(incons_str));
                }
                vty_out(vty, " Inconsistencies: %s\n",
                                incons_str);
                if (listcount(es->es_frag_list)) {
                        vty_out(vty, " Fragments:\n");
                        bgp_evpn_es_frag_show_detail(vty, es);
                }
                if (listcount(es->es_vtep_list)) {
                        vty_out(vty, " VTEPs:\n");
                        bgp_evpn_es_vteps_show_detail(vty, es);
                }
                vty_out(vty, "\n");
        }
}

/* Display all ESs */
void bgp_evpn_es_show(struct vty *vty, bool uj, bool detail)
{
        struct bgp_evpn_es *es;
        json_object *json_array = NULL;
        json_object *json = NULL;

        if (uj) {
                /* create an array of ESs */
                json_array = json_object_new_array();
        } else {
                if (!detail) {
                        vty_out(vty,
                                "ES Flags: B - bypass, L local, R remote, I inconsistent\n");
                        vty_out(vty,
                                "VTEP Flags: E ESR/Type-4, A active nexthop\n");
                        vty_out(vty,
                                "%-30s %-5s %-21s %-8s %s\n",
                                "ESI", "Flags", "RD", "#VNIs", "VTEPs");
                }
        }

        RB_FOREACH(es, bgp_es_rb_head, &bgp_mh_info->es_rb_tree) {
                if (uj)
                        /* create a separate json object for each ES */
                        json = json_object_new_object();
                if (detail)
                        bgp_evpn_es_show_entry_detail(vty, es, json);
                else
                        bgp_evpn_es_show_entry(vty, es, json);
                /* add ES to the json array */
                if (uj)
                        json_object_array_add(json_array, json);
        }

        /* print the array of json-ESs */
        if (uj)
                vty_json(vty, json_array);
}

/* Display specific ES */
void bgp_evpn_es_show_esi(struct vty *vty, esi_t *esi, bool uj)
{
        struct bgp_evpn_es *es;
        json_object *json = NULL;

        if (uj)
                json = json_object_new_object();

        es = bgp_evpn_es_find(esi);
        if (es) {
                bgp_evpn_es_show_entry_detail(vty, es, json);
        } else {
                if (!uj)
                        vty_out(vty, "ESI not found\n");
        }

        if (uj)
                vty_json(vty, json);
}

/*****************************************************************************/
/* Ethernet Segment to VRF association -
 * 1. Each ES-EVI entry is associated with a tenant VRF. This associaton
 * triggers the creation of an ES-VRF entry.
 * 2. The ES-VRF entry is maintained for the purpose of L3-NHG creation
 * 3. Type-2/MAC-IP routes are imported into a tenant VRF and programmed as
 * a /32 or host route entry in the dataplane. If the destination of
 * the host route is a remote-ES the route is programmed with the
 * corresponding (keyed in by {vrf,ES-id}) L3-NHG.
 * 4. The reason for this indirection (route->L3-NHG, L3-NHG->list-of-VTEPs)
 * is to avoid route updates to the dplane when a remote-ES link flaps i.e.
 * instead of updating all the dependent routes the NHG's contents are updated.
 * This reduces the amount of datplane updates (nhg updates vs. route updates)
 * allowing for a faster failover.
 *
 * XXX - can the L3 SVI index change without change in vpn->bgp_vrf
 * association? If yes we need to handle that by updating all the L3 NHGs
 * in that VRF.
 */
/******************************** L3 NHG management *************************/
static void bgp_evpn_l3nhg_zebra_add_v4_or_v6(struct bgp_evpn_es_vrf *es_vrf,
                                              bool v4_nhg)
{
        uint32_t nhg_id = v4_nhg ? es_vrf->nhg_id : es_vrf->v6_nhg_id;
        struct bgp_evpn_es *es = es_vrf->es;
        struct listnode *node;
        struct bgp_evpn_es_vtep *es_vtep;
        struct nexthop nh;
        struct zapi_nexthop *api_nh;
        struct zapi_nhg api_nhg = {};

        /* Skip installation of L3-NHG if host routes used */
        if (!nhg_id)
                return;

        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug("es %s vrf %u %s nhg %u to zebra", es->esi_str,
                           es_vrf->bgp_vrf->vrf_id,
                           v4_nhg ? "v4_nhg" : "v6_nhg", nhg_id);

        frrtrace(4, frr_bgp, evpn_mh_nhg_zsend, true, v4_nhg, nhg_id, es_vrf);

        /* only the gateway ip changes for each NH. rest of the params
         * are constant
         */
        memset(&nh, 0, sizeof(nh));
        nh.vrf_id = es_vrf->bgp_vrf->vrf_id;
        nh.flags = NEXTHOP_FLAG_ONLINK;
        nh.ifindex = es_vrf->bgp_vrf->l3vni_svi_ifindex;
        nh.weight = 1;
        nh.type =
                v4_nhg ? NEXTHOP_TYPE_IPV4_IFINDEX : NEXTHOP_TYPE_IPV6_IFINDEX;

        api_nhg.id = nhg_id;
        for (ALL_LIST_ELEMENTS_RO(es->es_vtep_list, node, es_vtep)) {
                if (!CHECK_FLAG(es_vtep->flags, BGP_EVPNES_VTEP_ACTIVE))
                        continue;

                /* Don't overrun the zapi buffer. */
                if (api_nhg.nexthop_num == MULTIPATH_NUM)
                        break;

                /* overwrite the gw */
                if (v4_nhg)
                        nh.gate.ipv4 = es_vtep->vtep_ip;
                else
                        ipv4_to_ipv4_mapped_ipv6(&nh.gate.ipv6,
                                                 es_vtep->vtep_ip);

                /* convert to zapi format */
                api_nh = &api_nhg.nexthops[api_nhg.nexthop_num];
                zapi_nexthop_from_nexthop(api_nh, &nh);

                ++api_nhg.nexthop_num;
                if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                        zlog_debug("nhg %u vtep %pI4 l3-svi %d", api_nhg.id,
                                   &es_vtep->vtep_ip,
                                   es_vrf->bgp_vrf->l3vni_svi_ifindex);

                frrtrace(3, frr_bgp, evpn_mh_nh_zsend, nhg_id, es_vtep, es_vrf);
        }

        if (!api_nhg.nexthop_num)
                return;

        zclient_nhg_send(zclient, ZEBRA_NHG_ADD, &api_nhg);
}

static bool bgp_evpn_l3nhg_zebra_ok(struct bgp_evpn_es_vrf *es_vrf)
{
        if (!bgp_mh_info->host_routes_use_l3nhg && !bgp_mh_info->install_l3nhg)
                return false;

        /* Check socket. */
        if (!zclient || zclient->sock < 0)
                return false;

        return true;
}

static void bgp_evpn_l3nhg_zebra_add(struct bgp_evpn_es_vrf *es_vrf)
{
        if (!bgp_evpn_l3nhg_zebra_ok(es_vrf))
                return;

        bgp_evpn_l3nhg_zebra_add_v4_or_v6(es_vrf, true /*v4_nhg*/);
        bgp_evpn_l3nhg_zebra_add_v4_or_v6(es_vrf, false /*v4_nhg*/);
}

static void bgp_evpn_l3nhg_zebra_del_v4_or_v6(struct bgp_evpn_es_vrf *es_vrf,
                                              bool v4_nhg)
{
        struct zapi_nhg api_nhg = {};

        api_nhg.id = v4_nhg ? es_vrf->nhg_id : es_vrf->v6_nhg_id;

        /* Skip installation of L3-NHG if host routes used */
        if (!api_nhg.id)
                return;

        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug("es %s vrf %u %s nhg %u to zebra",
                           es_vrf->es->esi_str, es_vrf->bgp_vrf->vrf_id,
                           v4_nhg ? "v4_nhg" : "v6_nhg", api_nhg.id);


        frrtrace(4, frr_bgp, evpn_mh_nhg_zsend, false, v4_nhg, api_nhg.id,
                 es_vrf);

        zclient_nhg_send(zclient, ZEBRA_NHG_DEL, &api_nhg);
}

static void bgp_evpn_l3nhg_zebra_del(struct bgp_evpn_es_vrf *es_vrf)
{
        if (!bgp_evpn_l3nhg_zebra_ok(es_vrf))
                return;

        bgp_evpn_l3nhg_zebra_del_v4_or_v6(es_vrf, true /*v4_nhg*/);
        bgp_evpn_l3nhg_zebra_del_v4_or_v6(es_vrf, false /*v4_nhg*/);
}

static void bgp_evpn_l3nhg_deactivate(struct bgp_evpn_es_vrf *es_vrf)
{
        if (!(es_vrf->flags & BGP_EVPNES_VRF_NHG_ACTIVE))
                return;

        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug("es %s vrf %u nhg %u de-activate",
                           es_vrf->es->esi_str, es_vrf->bgp_vrf->vrf_id,
                           es_vrf->nhg_id);
        bgp_evpn_l3nhg_zebra_del(es_vrf);
        es_vrf->flags &= ~BGP_EVPNES_VRF_NHG_ACTIVE;
        /* MAC-IPs can now be installed via the L3NHG */
        bgp_evpn_es_path_update_on_es_vrf_chg(es_vrf, "l3nhg-deactivate");
}

static void bgp_evpn_l3nhg_activate(struct bgp_evpn_es_vrf *es_vrf, bool update)
{
        if (!bgp_evpn_es_get_active_vtep_cnt(es_vrf->es)) {
                bgp_evpn_l3nhg_deactivate(es_vrf);
                return;
        }

        if (es_vrf->flags & BGP_EVPNES_VRF_NHG_ACTIVE) {
                if (!update)
                        return;
        } else {
                if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                        zlog_debug("es %s vrf %u nhg %u activate",
                                   es_vrf->es->esi_str, es_vrf->bgp_vrf->vrf_id,
                                   es_vrf->nhg_id);
                es_vrf->flags |= BGP_EVPNES_VRF_NHG_ACTIVE;
                /* MAC-IPs can now be installed via the L3NHG */
                bgp_evpn_es_path_update_on_es_vrf_chg(es_vrf, "l3nhg_activate");
        }

        bgp_evpn_l3nhg_zebra_add(es_vrf);
}

/* when a VTEP is activated or de-activated against an ES associated
 * VRFs' NHG needs to be updated
 */
static void bgp_evpn_l3nhg_update_on_vtep_chg(struct bgp_evpn_es *es)
{
        struct bgp_evpn_es_vrf *es_vrf;
        struct listnode *es_vrf_node;

        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug("es %s nhg update on vtep chg", es->esi_str);

        for (ALL_LIST_ELEMENTS_RO(es->es_vrf_list, es_vrf_node, es_vrf))
                bgp_evpn_l3nhg_activate(es_vrf, true /* update */);
}

/* compare ES-IDs for the ES-VRF RB tree maintained per-VRF */
static int bgp_es_vrf_rb_cmp(const struct bgp_evpn_es_vrf *es_vrf1,
                             const struct bgp_evpn_es_vrf *es_vrf2)
{
        return memcmp(&es_vrf1->es->esi, &es_vrf2->es->esi, ESI_BYTES);
}
RB_GENERATE(bgp_es_vrf_rb_head, bgp_evpn_es_vrf, rb_node, bgp_es_vrf_rb_cmp);

/* Initialize the ES tables maintained per-tenant vrf */
void bgp_evpn_vrf_es_init(struct bgp *bgp_vrf)
{
        /* Initialize the ES-VRF RB tree */
        RB_INIT(bgp_es_vrf_rb_head, &bgp_vrf->es_vrf_rb_tree);
}

/* find the ES-VRF in the per-VRF RB tree */
static struct bgp_evpn_es_vrf *bgp_evpn_es_vrf_find(struct bgp_evpn_es *es,
                                                    struct bgp *bgp_vrf)
{
        struct bgp_evpn_es_vrf es_vrf;

        es_vrf.es = es;

        return RB_FIND(bgp_es_vrf_rb_head, &bgp_vrf->es_vrf_rb_tree, &es_vrf);
}

/* allocate a new ES-VRF and setup L3NHG for it */
static struct bgp_evpn_es_vrf *bgp_evpn_es_vrf_create(struct bgp_evpn_es *es,
                                                      struct bgp *bgp_vrf)
{
        struct bgp_evpn_es_vrf *es_vrf;

        es_vrf = XCALLOC(MTYPE_BGP_EVPN_ES_VRF, sizeof(*es_vrf));

        es_vrf->es = es;
        es_vrf->bgp_vrf = bgp_vrf;

        /* insert into the VRF-ESI rb tree */
        RB_INSERT(bgp_es_vrf_rb_head, &bgp_vrf->es_vrf_rb_tree, es_vrf);

        /* add to the ES's VRF list */
        listnode_init(&es_vrf->es_listnode, es_vrf);
        listnode_add(es->es_vrf_list, &es_vrf->es_listnode);

        /* setup the L3 NHG id for the ES */
        es_vrf->nhg_id = bgp_l3nhg_id_alloc();
        es_vrf->v6_nhg_id = bgp_l3nhg_id_alloc();

        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug("es %s vrf %u nhg %u v6_nhg %d create", es->esi_str,
                           bgp_vrf->vrf_id, es_vrf->nhg_id, es_vrf->v6_nhg_id);
        bgp_evpn_l3nhg_activate(es_vrf, false /* update */);

        /* update paths in the VRF that may already be associated with
         * this destination ES
         */
        bgp_evpn_es_path_update_on_es_vrf_chg(es_vrf, "es-vrf-create");

        return es_vrf;
}

/* remove the L3-NHG associated with the ES-VRF and free it */
static void bgp_evpn_es_vrf_delete(struct bgp_evpn_es_vrf *es_vrf)
{
        struct bgp_evpn_es *es = es_vrf->es;
        struct bgp *bgp_vrf = es_vrf->bgp_vrf;

        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug("es %s vrf %u nhg %u delete", es->esi_str,
                           bgp_vrf->vrf_id, es_vrf->nhg_id);

        /* Remove the NHG resources */
        bgp_evpn_l3nhg_deactivate(es_vrf);
        if (es_vrf->nhg_id)
                bgp_l3nhg_id_free(es_vrf->nhg_id);
        es_vrf->nhg_id = 0;
        if (es_vrf->v6_nhg_id)
                bgp_l3nhg_id_free(es_vrf->v6_nhg_id);
        es_vrf->v6_nhg_id = 0;

        /* remove from the ES's VRF list */
        list_delete_node(es->es_vrf_list, &es_vrf->es_listnode);

        /* remove from the VRF-ESI rb tree */
        RB_REMOVE(bgp_es_vrf_rb_head, &bgp_vrf->es_vrf_rb_tree, es_vrf);

        /* update paths in the VRF that may already be associated with
         * this destination ES
         */
        bgp_evpn_es_path_update_on_es_vrf_chg(es_vrf, "es-vrf-delete");

        XFREE(MTYPE_BGP_EVPN_ES_VRF, es_vrf);
}

/* deref and delete if there are no references */
void bgp_evpn_es_vrf_deref(struct bgp_evpn_es_evi *es_evi)
{
        struct bgp_evpn_es_vrf *es_vrf = es_evi->es_vrf;

        if (!es_vrf)
                return;

        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug("es-evi %s vni %u vrf %u de-ref",
                           es_evi->es->esi_str, es_evi->vpn->vni,
                           es_vrf->bgp_vrf->vrf_id);

        es_evi->es_vrf = NULL;
        if (es_vrf->ref_cnt)
                --es_vrf->ref_cnt;

        if (!es_vrf->ref_cnt)
                bgp_evpn_es_vrf_delete(es_vrf);
}

/* find or create and reference */
void bgp_evpn_es_vrf_ref(struct bgp_evpn_es_evi *es_evi, struct bgp *bgp_vrf)
{
        struct bgp_evpn_es *es = es_evi->es;
        struct bgp_evpn_es_vrf *es_vrf = es_evi->es_vrf;
        struct bgp *old_bgp_vrf = NULL;

        if (es_vrf)
                old_bgp_vrf = es_vrf->bgp_vrf;

        if (old_bgp_vrf == bgp_vrf)
                return;

        /* deref the old ES-VRF */
        bgp_evpn_es_vrf_deref(es_evi);

        if (!bgp_vrf)
                return;

        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug("es-evi %s vni %u vrf %u ref", es_evi->es->esi_str,
                           es_evi->vpn->vni, bgp_vrf->vrf_id);

        /* find-create the new ES-VRF */
        es_vrf = bgp_evpn_es_vrf_find(es, bgp_vrf);
        if (!es_vrf)
                es_vrf = bgp_evpn_es_vrf_create(es, bgp_vrf);

        es_evi->es_vrf = es_vrf;
        ++es_vrf->ref_cnt;
}

/* When the L2-VNI is associated with a L3-VNI/VRF update all the
 * associated ES-EVI entries
 */
void bgp_evpn_es_evi_vrf_deref(struct bgpevpn *vpn)
{
        struct bgp_evpn_es_evi *es_evi;

        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug("es-vrf de-ref for vni %u", vpn->vni);

        RB_FOREACH (es_evi, bgp_es_evi_rb_head, &vpn->es_evi_rb_tree)
                bgp_evpn_es_vrf_deref(es_evi);
}
void bgp_evpn_es_evi_vrf_ref(struct bgpevpn *vpn)
{
        struct bgp_evpn_es_evi *es_evi;

        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug("es-vrf ref for vni %u", vpn->vni);

        RB_FOREACH (es_evi, bgp_es_evi_rb_head, &vpn->es_evi_rb_tree)
                bgp_evpn_es_vrf_ref(es_evi, vpn->bgp_vrf);
}

/* 1. If ES-VRF is not present install the host route with the exploded/flat
 * multi-path list.
 * 2. If ES-VRF is present -
 * - if L3NHG has not been activated for the ES-VRF (this could be because
 *   all the PEs attached to the VRF are down) do not install the route
 *   in zebra.
 * - if L3NHG has been activated install the route via that L3NHG
 */
void bgp_evpn_es_vrf_use_nhg(struct bgp *bgp_vrf, esi_t *esi, bool *use_l3nhg,
                             bool *is_l3nhg_active,
                             struct bgp_evpn_es_vrf **es_vrf_p)
{
        struct bgp_evpn_es *es;
        struct bgp_evpn_es_vrf *es_vrf;

        if (!bgp_mh_info->host_routes_use_l3nhg)
                return;

        es = bgp_evpn_es_find(esi);
        if (!es)
                return;

        es_vrf = bgp_evpn_es_vrf_find(es, bgp_vrf);
        if (!es_vrf)
                return;

        *use_l3nhg = true;
        if (es_vrf->flags & BGP_EVPNES_VRF_NHG_ACTIVE)
                *is_l3nhg_active = true;
        if (es_vrf_p)
                *es_vrf_p = es_vrf;
}

/* returns false if legacy-exploded mp needs to be used for route install */
bool bgp_evpn_path_es_use_nhg(struct bgp *bgp_vrf, struct bgp_path_info *pi,
                              uint32_t *nhg_p)
{
        esi_t *esi;
        struct bgp_evpn_es_vrf *es_vrf = NULL;
        struct bgp_path_info *parent_pi;
        struct bgp_node *rn;
        struct prefix_evpn *evp;
        struct bgp_path_info *mpinfo;
        bool use_l3nhg = false;
        bool is_l3nhg_active = false;

        *nhg_p = 0;

        /* we don't support NHG for routes leaked from another VRF yet */
        if (pi->extra && pi->extra->bgp_orig)
                return false;

        parent_pi = get_route_parent_evpn(pi);
        if (!parent_pi)
                return false;

        rn = parent_pi->net;
        if (!rn)
                return false;

        evp = (struct prefix_evpn *)&rn->p;
        if (evp->prefix.route_type != BGP_EVPN_MAC_IP_ROUTE)
                return false;

        /* non-es path, use legacy-exploded multipath */
        esi = bgp_evpn_attr_get_esi(parent_pi->attr);
        if (!memcmp(esi, zero_esi, sizeof(*esi)))
                return false;

        bgp_evpn_es_vrf_use_nhg(bgp_vrf, esi, &use_l3nhg, &is_l3nhg_active,
                                &es_vrf);

        /* L3NHG support is disabled, use legacy-exploded multipath */
        if (!use_l3nhg)
                return false;

        /* if the NHG has not been installed we cannot install the route yet,
         * return a 0-NHG to indicate that
         */
        if (!is_l3nhg_active)
                return true;

        /* this needs to be set the v6NHG if v6route */
        if (is_evpn_prefix_ipaddr_v6(evp))
                *nhg_p = es_vrf->v6_nhg_id;
        else
                *nhg_p = es_vrf->nhg_id;

        for (mpinfo = bgp_path_info_mpath_next(pi); mpinfo;
             mpinfo = bgp_path_info_mpath_next(mpinfo)) {
                /* if any of the paths have a different ESI we can't use
                 * the NHG associated with the ES. fallback to legacy-exploded
                 * multipath
                 */
                if (memcmp(esi, bgp_evpn_attr_get_esi(mpinfo->attr),
                           sizeof(*esi)))
                        return false;
        }

        return true;
}

static void bgp_evpn_es_vrf_show_entry(struct vty *vty,
                                       struct bgp_evpn_es_vrf *es_vrf,
                                       json_object *json)
{
        struct bgp_evpn_es *es = es_vrf->es;
        struct bgp *bgp_vrf = es_vrf->bgp_vrf;

        if (json) {
                json_object *json_types;

                json_object_string_add(json, "esi", es->esi_str);
                json_object_string_add(json, "vrf", bgp_vrf->name);

                if (es_vrf->flags & (BGP_EVPNES_VRF_NHG_ACTIVE)) {
                        json_types = json_object_new_array();
                        if (es_vrf->flags & BGP_EVPNES_VRF_NHG_ACTIVE)
                                json_array_string_add(json_types, "active");
                        json_object_object_add(json, "flags", json_types);
                }

                json_object_int_add(json, "ipv4NHG", es_vrf->nhg_id);
                json_object_int_add(json, "ipv6NHG", es_vrf->v6_nhg_id);
                json_object_int_add(json, "refCount", es_vrf->ref_cnt);
        } else {
                char flags_str[4];

                flags_str[0] = '\0';
                if (es_vrf->flags & BGP_EVPNES_VRF_NHG_ACTIVE)
                        strlcat(flags_str, "A", sizeof(flags_str));

                vty_out(vty, "%-30s %-15s %-5s %-8u %-8u %u\n", es->esi_str,
                        bgp_vrf->name, flags_str, es_vrf->nhg_id,
                        es_vrf->v6_nhg_id, es_vrf->ref_cnt);
        }
}

static void bgp_evpn_es_vrf_show_es(struct vty *vty, json_object *json_array,
                                    struct bgp_evpn_es *es)
{
        json_object *json = NULL;
        struct listnode *es_vrf_node;
        struct bgp_evpn_es_vrf *es_vrf;

        for (ALL_LIST_ELEMENTS_RO(es->es_vrf_list, es_vrf_node, es_vrf)) {
                /* create a separate json object for each ES-VRF */
                if (json_array)
                        json = json_object_new_object();
                bgp_evpn_es_vrf_show_entry(vty, es_vrf, json);
                /* add ES-VRF to the json array */
                if (json_array)
                        json_object_array_add(json_array, json);
        }
}

/* Display all ES VRFs */
void bgp_evpn_es_vrf_show(struct vty *vty, bool uj, struct bgp_evpn_es *es)
{
        json_object *json_array = NULL;

        if (uj) {
                /* create an array of ESs */
                json_array = json_object_new_array();
        } else {
                vty_out(vty, "ES-VRF Flags: A Active\n");
                vty_out(vty, "%-30s %-15s %-5s %-8s %-8s %s\n", "ESI", "VRF",
                        "Flags", "IPv4-NHG", "IPv6-NHG", "Ref");
        }

        if (es) {
                bgp_evpn_es_vrf_show_es(vty, json_array, es);
        } else {
                RB_FOREACH (es, bgp_es_rb_head, &bgp_mh_info->es_rb_tree)
                        bgp_evpn_es_vrf_show_es(vty, json_array, es);
        }

        /* print the array of json-ESs */
        if (uj)
                vty_json(vty, json_array);
}

/* Display specific ES VRF */
void bgp_evpn_es_vrf_show_esi(struct vty *vty, esi_t *esi, bool uj)
{
        struct bgp_evpn_es *es;

        es = bgp_evpn_es_find(esi);
        if (es) {
                bgp_evpn_es_vrf_show(vty, uj, es);
        } else {
                if (!uj)
                        vty_out(vty, "ESI not found\n");
        }
}

/*****************************************************************************/
/* Ethernet Segment to EVI association -
 * 1. The ES-EVI entry is maintained as a RB tree per L2-VNI
 * (bgpevpn->es_evi_rb_tree).
 * 2. Each local ES-EVI entry is rxed from zebra and then used by BGP to
 * advertises an EAD-EVI (Type-1 EVPN) route
 * 3. The remote ES-EVI is created when a bgp_evpn_es_evi_vtep references
 * it.
 */

/* A list of remote VTEPs is maintained for each ES-EVI. This list includes -
 * 1. VTEPs for which we have imported the EAD-per-ES Type1 route
 * 2. VTEPs for which we have imported the EAD-per-EVI Type1 route
 * VTEPs for which both routes have been rxed are activated. Activation
 * creates a NHG in the parent ES.
 */
static int bgp_evpn_es_evi_vtep_cmp(void *p1, void *p2)
{
        const struct bgp_evpn_es_evi_vtep *evi_vtep1 = p1;
        const struct bgp_evpn_es_evi_vtep *evi_vtep2 = p2;

        return evi_vtep1->vtep_ip.s_addr - evi_vtep2->vtep_ip.s_addr;
}

static struct bgp_evpn_es_evi_vtep *bgp_evpn_es_evi_vtep_new(
                struct bgp_evpn_es_evi *es_evi, struct in_addr vtep_ip)
{
        struct bgp_evpn_es_evi_vtep *evi_vtep;

        evi_vtep = XCALLOC(MTYPE_BGP_EVPN_ES_EVI_VTEP, sizeof(*evi_vtep));

        evi_vtep->es_evi = es_evi;
        evi_vtep->vtep_ip.s_addr = vtep_ip.s_addr;
        listnode_init(&evi_vtep->es_evi_listnode, evi_vtep);
        listnode_add_sort(es_evi->es_evi_vtep_list, &evi_vtep->es_evi_listnode);

        return evi_vtep;
}

static void bgp_evpn_es_evi_vtep_free(struct bgp_evpn_es_evi_vtep *evi_vtep)
{
        struct bgp_evpn_es_evi *es_evi = evi_vtep->es_evi;

        if (evi_vtep->flags & (BGP_EVPN_EVI_VTEP_EAD))
                /* as long as there is some reference we can't free it */
                return;

        list_delete_node(es_evi->es_evi_vtep_list, &evi_vtep->es_evi_listnode);
        XFREE(MTYPE_BGP_EVPN_ES_EVI_VTEP, evi_vtep);
}

/* check if VTEP is already part of the list */
static struct bgp_evpn_es_evi_vtep *bgp_evpn_es_evi_vtep_find(
                struct bgp_evpn_es_evi *es_evi, struct in_addr vtep_ip)
{
        struct listnode *node = NULL;
        struct bgp_evpn_es_evi_vtep *evi_vtep;

        for (ALL_LIST_ELEMENTS_RO(es_evi->es_evi_vtep_list, node, evi_vtep)) {
                if (evi_vtep->vtep_ip.s_addr == vtep_ip.s_addr)
                        return evi_vtep;
        }
        return NULL;
}

/* A VTEP can be added as "active" attach to an ES if EAD-per-ES and
 * EAD-per-EVI routes are rxed from it.
 */
static void bgp_evpn_es_evi_vtep_re_eval_active(struct bgp *bgp,
                struct bgp_evpn_es_evi_vtep *evi_vtep)
{
        bool old_active;
        bool new_active;
        uint32_t ead_activity_flags;

        old_active = CHECK_FLAG(evi_vtep->flags, BGP_EVPN_EVI_VTEP_ACTIVE);

        if (bgp_mh_info->ead_evi_rx)
                /* Both EAD-per-ES and EAD-per-EVI routes must be rxed from a PE
                 * before it can be activated.
                 */
                ead_activity_flags = BGP_EVPN_EVI_VTEP_EAD;
        else
                /* EAD-per-ES is sufficent to activate the PE */
                ead_activity_flags = BGP_EVPN_EVI_VTEP_EAD_PER_ES;

        if ((evi_vtep->flags & ead_activity_flags) == ead_activity_flags)
                SET_FLAG(evi_vtep->flags, BGP_EVPN_EVI_VTEP_ACTIVE);
        else
                UNSET_FLAG(evi_vtep->flags, BGP_EVPN_EVI_VTEP_ACTIVE);

        new_active = CHECK_FLAG(evi_vtep->flags, BGP_EVPN_EVI_VTEP_ACTIVE);

        if (old_active == new_active)
                return;

        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug("es %s evi %u vtep %pI4 %s",
                           evi_vtep->es_evi->es->esi_str,
                           evi_vtep->es_evi->vpn->vni, &evi_vtep->vtep_ip,
                           new_active ? "active" : "inactive");

        /* add VTEP to parent es */
        if (new_active) {
                struct bgp_evpn_es_vtep *es_vtep;

                es_vtep = bgp_evpn_es_vtep_add(bgp, evi_vtep->es_evi->es,
                                               evi_vtep->vtep_ip, false /*esr*/,
                                               0, 0);
                evi_vtep->es_vtep = es_vtep;
        } else {
                if (evi_vtep->es_vtep) {
                        bgp_evpn_es_vtep_do_del(bgp, evi_vtep->es_vtep,
                                        false /*esr*/);
                        evi_vtep->es_vtep = NULL;
                }
        }
        /* queue up the parent es for background consistency checks */
        bgp_evpn_es_cons_checks_pend_add(evi_vtep->es_evi->es);
}

static void bgp_evpn_es_evi_vtep_add(struct bgp *bgp,
                struct bgp_evpn_es_evi *es_evi, struct in_addr vtep_ip,
                bool ead_es)
{
        struct bgp_evpn_es_evi_vtep *evi_vtep;

        evi_vtep = bgp_evpn_es_evi_vtep_find(es_evi, vtep_ip);

        if (!evi_vtep)
                evi_vtep = bgp_evpn_es_evi_vtep_new(es_evi, vtep_ip);

        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug("add es %s evi %u vtep %pI4 %s",
                           evi_vtep->es_evi->es->esi_str,
                           evi_vtep->es_evi->vpn->vni, &evi_vtep->vtep_ip,
                           ead_es ? "ead_es" : "ead_evi");

        if (ead_es)
                SET_FLAG(evi_vtep->flags, BGP_EVPN_EVI_VTEP_EAD_PER_ES);
        else
                SET_FLAG(evi_vtep->flags, BGP_EVPN_EVI_VTEP_EAD_PER_EVI);

        bgp_evpn_es_evi_vtep_re_eval_active(bgp, evi_vtep);
}

static void bgp_evpn_es_evi_vtep_del(struct bgp *bgp,
                struct bgp_evpn_es_evi *es_evi, struct in_addr vtep_ip,
                bool ead_es)
{
        struct bgp_evpn_es_evi_vtep *evi_vtep;

        evi_vtep = bgp_evpn_es_evi_vtep_find(es_evi, vtep_ip);
        if (!evi_vtep)
                return;

        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug("del es %s evi %u vtep %pI4 %s",
                           evi_vtep->es_evi->es->esi_str,
                           evi_vtep->es_evi->vpn->vni, &evi_vtep->vtep_ip,
                           ead_es ? "ead_es" : "ead_evi");

        if (ead_es)
                UNSET_FLAG(evi_vtep->flags, BGP_EVPN_EVI_VTEP_EAD_PER_ES);
        else
                UNSET_FLAG(evi_vtep->flags, BGP_EVPN_EVI_VTEP_EAD_PER_EVI);

        bgp_evpn_es_evi_vtep_re_eval_active(bgp, evi_vtep);
        bgp_evpn_es_evi_vtep_free(evi_vtep);
}

/* compare ES-IDs for the ES-EVI RB tree maintained per-VNI */
static int bgp_es_evi_rb_cmp(const struct bgp_evpn_es_evi *es_evi1,
                const struct bgp_evpn_es_evi *es_evi2)
{
        return memcmp(&es_evi1->es->esi, &es_evi2->es->esi, ESI_BYTES);
}
RB_GENERATE(bgp_es_evi_rb_head, bgp_evpn_es_evi, rb_node, bgp_es_evi_rb_cmp);

/* find the ES-EVI in the per-L2-VNI RB tree */
static struct bgp_evpn_es_evi *bgp_evpn_es_evi_find(struct bgp_evpn_es *es,
                struct bgpevpn *vpn)
{
        struct bgp_evpn_es_evi es_evi;

        es_evi.es = es;

        return RB_FIND(bgp_es_evi_rb_head, &vpn->es_evi_rb_tree, &es_evi);
}

/* allocate a new ES-EVI and insert it into the per-L2-VNI and per-ES
 * tables.
 */
static struct bgp_evpn_es_evi *bgp_evpn_es_evi_new(struct bgp_evpn_es *es,
                struct bgpevpn *vpn)
{
        struct bgp_evpn_es_evi *es_evi;

        es_evi = XCALLOC(MTYPE_BGP_EVPN_ES_EVI, sizeof(*es_evi));

        es_evi->es = es;
        es_evi->vpn = vpn;

        /* Initialise the VTEP list */
        es_evi->es_evi_vtep_list = list_new();
        listset_app_node_mem(es_evi->es_evi_vtep_list);
        es_evi->es_evi_vtep_list->cmp = bgp_evpn_es_evi_vtep_cmp;

        /* insert into the VNI-ESI rb tree */
        RB_INSERT(bgp_es_evi_rb_head, &vpn->es_evi_rb_tree, es_evi);

        /* add to the ES's VNI list */
        listnode_init(&es_evi->es_listnode, es_evi);
        listnode_add(es->es_evi_list, &es_evi->es_listnode);

        bgp_evpn_es_vrf_ref(es_evi, vpn->bgp_vrf);

        return es_evi;
}

/* remove the ES-EVI from the per-L2-VNI and per-ES tables and free
 * up the memory.
 */
static struct bgp_evpn_es_evi *
bgp_evpn_es_evi_free(struct bgp_evpn_es_evi *es_evi)
{
        struct bgp_evpn_es *es = es_evi->es;
        struct bgpevpn *vpn = es_evi->vpn;

        /* cannot free the element as long as there is a local or remote
         * reference
         */
        if (es_evi->flags & (BGP_EVPNES_EVI_LOCAL | BGP_EVPNES_EVI_REMOTE))
                return es_evi;
        bgp_evpn_es_frag_evi_del(es_evi, false);
        bgp_evpn_es_vrf_deref(es_evi);

        /* remove from the ES's VNI list */
        list_delete_node(es->es_evi_list, &es_evi->es_listnode);

        /* remove from the VNI-ESI rb tree */
        RB_REMOVE(bgp_es_evi_rb_head, &vpn->es_evi_rb_tree, es_evi);

        /* free the VTEP list */
        list_delete(&es_evi->es_evi_vtep_list);

        /* remove from the VNI-ESI rb tree */
        XFREE(MTYPE_BGP_EVPN_ES_EVI, es_evi);

        return NULL;
}

/* init local info associated with the ES-EVI */
static void bgp_evpn_es_evi_local_info_set(struct bgp_evpn_es_evi *es_evi)
{
        struct bgpevpn *vpn = es_evi->vpn;

        if (CHECK_FLAG(es_evi->flags, BGP_EVPNES_EVI_LOCAL))
                return;

        SET_FLAG(es_evi->flags, BGP_EVPNES_EVI_LOCAL);
        listnode_init(&es_evi->l2vni_listnode, es_evi);
        listnode_add(vpn->local_es_evi_list, &es_evi->l2vni_listnode);
        bgp_evpn_es_frag_evi_add(es_evi);
}

/* clear any local info associated with the ES-EVI */
static struct bgp_evpn_es_evi *
bgp_evpn_es_evi_local_info_clear(struct bgp_evpn_es_evi *es_evi)
{
        struct bgpevpn *vpn = es_evi->vpn;

        UNSET_FLAG(es_evi->flags, BGP_EVPNES_EVI_LOCAL);
        list_delete_node(vpn->local_es_evi_list, &es_evi->l2vni_listnode);

        return bgp_evpn_es_evi_free(es_evi);
}

/* eval remote info associated with the ES */
static void bgp_evpn_es_evi_remote_info_re_eval(struct bgp_evpn_es_evi *es_evi)
{
        struct bgp_evpn_es *es = es_evi->es;

        /* if there are remote VTEPs the ES-EVI is classified as "remote" */
        if (listcount(es_evi->es_evi_vtep_list)) {
                if (!CHECK_FLAG(es_evi->flags, BGP_EVPNES_EVI_REMOTE)) {
                        SET_FLAG(es_evi->flags, BGP_EVPNES_EVI_REMOTE);
                        ++es->remote_es_evi_cnt;
                        /* set remote on the parent es */
                        bgp_evpn_es_remote_info_re_eval(es);
                }
        } else {
                if (CHECK_FLAG(es_evi->flags, BGP_EVPNES_EVI_REMOTE)) {
                        UNSET_FLAG(es_evi->flags, BGP_EVPNES_EVI_REMOTE);
                        if (es->remote_es_evi_cnt)
                                --es->remote_es_evi_cnt;
                        bgp_evpn_es_evi_free(es_evi);
                        /* check if "remote" can be cleared from the
                         * parent es.
                         */
                        bgp_evpn_es_remote_info_re_eval(es);
                }
        }
}

static struct bgp_evpn_es_evi *
bgp_evpn_local_es_evi_do_del(struct bgp_evpn_es_evi *es_evi)
{
        struct prefix_evpn p;
        struct bgp_evpn_es *es = es_evi->es;
        struct bgp *bgp;

        if (!CHECK_FLAG(es_evi->flags, BGP_EVPNES_EVI_LOCAL))
                return es_evi;

        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug("del local es %s evi %u",
                                es_evi->es->esi_str,
                                es_evi->vpn->vni);

        bgp = bgp_get_evpn();

        /* remove the es_evi from the es_frag before sending the update */
        bgp_evpn_es_frag_evi_del(es_evi, true);
        if (bgp) {
                /* update EAD-ES with new list of VNIs */
                if (bgp_evpn_local_es_is_active(es))
                        bgp_evpn_ead_es_route_update(bgp, es);

                /* withdraw and delete EAD-EVI */
                if (CHECK_FLAG(es->flags, BGP_EVPNES_ADV_EVI)) {
                        build_evpn_type1_prefix(&p, BGP_EVPN_AD_EVI_ETH_TAG,
                                        &es->esi, es->originator_ip);
                        if (bgp_evpn_ead_evi_route_delete(bgp, es, es_evi->vpn,
                                                          &p))
                                flog_err(EC_BGP_EVPN_ROUTE_DELETE,
                                        "%u: EAD-EVI route deletion failure for ESI %s VNI %u",
                                        bgp->vrf_id, es->esi_str,
                                        es_evi->vpn->vni);
                }
        }

        return bgp_evpn_es_evi_local_info_clear(es_evi);
}

int bgp_evpn_local_es_evi_del(struct bgp *bgp, esi_t *esi, vni_t vni)
{
        struct bgpevpn *vpn;
        struct bgp_evpn_es *es;
        struct bgp_evpn_es_evi *es_evi;
        char buf[ESI_STR_LEN];

        es = bgp_evpn_es_find(esi);
        if (!es) {
                flog_err(
                                EC_BGP_ES_CREATE,
                                "%u: Failed to deref VNI %d from ESI %s; ES not present",
                                bgp->vrf_id, vni,
                                esi_to_str(esi, buf, sizeof(buf)));
                return -1;
        }

        vpn = bgp_evpn_lookup_vni(bgp, vni);
        if (!vpn) {
                flog_err(
                                EC_BGP_ES_CREATE,
                                "%u: Failed to deref VNI %d from ESI %s; VNI not present",
                                bgp->vrf_id, vni, es->esi_str);
                return -1;
        }

        es_evi = bgp_evpn_es_evi_find(es, vpn);
        if (!es_evi) {
                flog_err(
                                EC_BGP_ES_CREATE,
                                "%u: Failed to deref VNI %d from ESI %s; ES-VNI not present",
                                bgp->vrf_id, vni, es->esi_str);
                return -1;
        }

        bgp_evpn_local_es_evi_do_del(es_evi);
        return 0;
}

/* Create ES-EVI and advertise the corresponding EAD routes */
int bgp_evpn_local_es_evi_add(struct bgp *bgp, esi_t *esi, vni_t vni)
{
        struct bgpevpn *vpn;
        struct prefix_evpn p;
        struct bgp_evpn_es *es;
        struct bgp_evpn_es_evi *es_evi;
        char buf[ESI_STR_LEN];

        es = bgp_evpn_es_find(esi);
        if (!es) {
                flog_err(
                                EC_BGP_ES_CREATE,
                                "%u: Failed to associate VNI %d with ESI %s; ES not present",
                                bgp->vrf_id, vni,
                                esi_to_str(esi, buf, sizeof(buf)));
                return -1;
        }

        vpn = bgp_evpn_lookup_vni(bgp, vni);
        if (!vpn) {
                flog_err(
                                EC_BGP_ES_CREATE,
                                "%u: Failed to associate VNI %d with ESI %s; VNI not present",
                                bgp->vrf_id, vni, es->esi_str);
                return -1;
        }

        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug("add local es %s evi %u",
                                es->esi_str, vni);

        es_evi = bgp_evpn_es_evi_find(es, vpn);

        if (es_evi) {
                if (CHECK_FLAG(es_evi->flags, BGP_EVPNES_EVI_LOCAL))
                        /* dup */
                        return 0;
        } else
                es_evi = bgp_evpn_es_evi_new(es, vpn);

        bgp_evpn_es_evi_local_info_set(es_evi);

        /* generate an EAD-EVI for this new VNI */
        if (CHECK_FLAG(es->flags, BGP_EVPNES_ADV_EVI)) {
                build_evpn_type1_prefix(&p, BGP_EVPN_AD_EVI_ETH_TAG, &es->esi,
                                        es->originator_ip);
                bgp_evpn_ead_evi_route_update(bgp, es, vpn, &p);
        }

        /* update EAD-ES */
        if (bgp_evpn_local_es_is_active(es))
                bgp_evpn_ead_es_route_update(bgp, es);

        return 0;
}

/* Add remote ES-EVI entry. This is actually the remote VTEP add and the
 * ES-EVI is implicity created on first VTEP's reference.
 */
int bgp_evpn_remote_es_evi_add(struct bgp *bgp, struct bgpevpn *vpn,
                const struct prefix_evpn *p)
{
        char buf[ESI_STR_LEN];
        struct bgp_evpn_es *es;
        struct bgp_evpn_es_evi *es_evi;
        bool ead_es;
        const esi_t *esi = &p->prefix.ead_addr.esi;

        if (!vpn)
                /* local EAD-ES need not be sent back to zebra */
                return 0;

        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug("add remote %s es %s evi %u vtep %pI4",
                           p->prefix.ead_addr.eth_tag ? "ead-es" : "ead-evi",
                           esi_to_str(esi, buf, sizeof(buf)), vpn->vni,
                           &p->prefix.ead_addr.ip.ipaddr_v4);

        es = bgp_evpn_es_find(esi);
        if (!es) {
                es = bgp_evpn_es_new(bgp, esi);
                if (!es) {
                        flog_err(EC_BGP_ES_CREATE,
                                "%u: Failed to allocate ES entry for ESI %s - at remote ES Add",
                                bgp->vrf_id, esi_to_str(esi, buf, sizeof(buf)));
                        return -1;
                }
        }

        es_evi = bgp_evpn_es_evi_find(es, vpn);
        if (!es_evi)
                es_evi = bgp_evpn_es_evi_new(es, vpn);

        ead_es = !!p->prefix.ead_addr.eth_tag;
        bgp_evpn_es_evi_vtep_add(bgp, es_evi, p->prefix.ead_addr.ip.ipaddr_v4,
                        ead_es);

        bgp_evpn_es_evi_remote_info_re_eval(es_evi);
        return 0;
}

/* A remote VTEP has withdrawn. The es-evi-vtep will be deleted and the
 * parent es-evi freed up implicitly in last VTEP's deref.
 */
int bgp_evpn_remote_es_evi_del(struct bgp *bgp, struct bgpevpn *vpn,
                const struct prefix_evpn *p)
{
        char buf[ESI_STR_LEN];
        struct bgp_evpn_es *es;
        struct bgp_evpn_es_evi *es_evi;
        bool ead_es;

        if (!vpn)
                /* local EAD-ES need not be sent back to zebra */
                return 0;

        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug(
                        "del remote %s es %s evi %u vtep %pI4",
                        p->prefix.ead_addr.eth_tag ? "ead-es" : "ead-evi",
                        esi_to_str(&p->prefix.ead_addr.esi, buf, sizeof(buf)),
                        vpn->vni, &p->prefix.ead_addr.ip.ipaddr_v4);

        es = bgp_evpn_es_find(&p->prefix.ead_addr.esi);
        if (!es) {
                if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                        zlog_debug("del remote %s es %s evi %u vtep %pI4, NO es",
                                   p->prefix.ead_addr.eth_tag ? "ead-es"
                                                              : "ead-evi",
                                   esi_to_str(&p->prefix.ead_addr.esi, buf,
                                              sizeof(buf)),
                                   vpn->vni,
                           &p->prefix.ead_addr.ip.ipaddr_v4);
                return 0;
        }
        es_evi = bgp_evpn_es_evi_find(es, vpn);
        if (!es_evi) {
                if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                        zlog_debug(
                                "del remote %s es %s evi %u vtep %pI4, NO es-evi",
                                p->prefix.ead_addr.eth_tag ? "ead-es"
                                                           : "ead-evi",
                                esi_to_str(&p->prefix.ead_addr.esi, buf,
                                           sizeof(buf)),
                                vpn->vni,
                                &p->prefix.ead_addr.ip.ipaddr_v4);
                return 0;
        }

        ead_es = !!p->prefix.ead_addr.eth_tag;
        bgp_evpn_es_evi_vtep_del(bgp, es_evi, p->prefix.ead_addr.ip.ipaddr_v4,
                        ead_es);
        bgp_evpn_es_evi_remote_info_re_eval(es_evi);
        return 0;
}

/* If a VNI is being deleted we need to force del all remote VTEPs */
static void bgp_evpn_remote_es_evi_flush(struct bgp_evpn_es_evi *es_evi)
{
        struct listnode *node = NULL;
        struct listnode *nnode = NULL;
        struct bgp_evpn_es_evi_vtep *evi_vtep;
        struct bgp *bgp;

        bgp = bgp_get_evpn();
        if (!bgp)
                return;

        /* delete all VTEPs */
        for (ALL_LIST_ELEMENTS(es_evi->es_evi_vtep_list, node, nnode,
                               evi_vtep)) {
                evi_vtep->flags &= ~(BGP_EVPN_EVI_VTEP_EAD_PER_ES
                                     | BGP_EVPN_EVI_VTEP_EAD_PER_EVI);
                bgp_evpn_es_evi_vtep_re_eval_active(bgp, evi_vtep);
                bgp_evpn_es_evi_vtep_free(evi_vtep);
        }
        /* delete the EVI */
        bgp_evpn_es_evi_remote_info_re_eval(es_evi);
}

/* Initialize the ES tables maintained per-L2_VNI */
void bgp_evpn_vni_es_init(struct bgpevpn *vpn)
{
        /* Initialize the ES-EVI RB tree */
        RB_INIT(bgp_es_evi_rb_head, &vpn->es_evi_rb_tree);

        /* Initialize the local list maintained for quick walks by type */
        vpn->local_es_evi_list = list_new();
        listset_app_node_mem(vpn->local_es_evi_list);
}

/* Cleanup the ES info maintained per-L2_VNI */
void bgp_evpn_vni_es_cleanup(struct bgpevpn *vpn)
{
        struct bgp_evpn_es_evi *es_evi;
        struct bgp_evpn_es_evi *es_evi_next;

        RB_FOREACH_SAFE(es_evi, bgp_es_evi_rb_head,
                        &vpn->es_evi_rb_tree, es_evi_next) {
                es_evi = bgp_evpn_local_es_evi_do_del(es_evi);
                if (es_evi)
                        bgp_evpn_remote_es_evi_flush(es_evi);
        }

        list_delete(&vpn->local_es_evi_list);
}

static char *bgp_evpn_es_evi_vteps_str(char *vtep_str,
                                       struct bgp_evpn_es_evi *es_evi,
                                       uint8_t vtep_str_size)
{
        char vtep_flag_str[BGP_EVPN_FLAG_STR_SZ];
        struct listnode *node;
        struct bgp_evpn_es_evi_vtep *evi_vtep;
        bool first = true;
        char ip_buf[INET6_ADDRSTRLEN];

        vtep_str[0] = '\0';
        for (ALL_LIST_ELEMENTS_RO(es_evi->es_evi_vtep_list, node, evi_vtep)) {
                vtep_flag_str[0] = '\0';
                if (evi_vtep->flags & BGP_EVPN_EVI_VTEP_EAD_PER_ES)
                        strlcat(vtep_flag_str, "E", sizeof(vtep_flag_str));
                if (evi_vtep->flags & BGP_EVPN_EVI_VTEP_EAD_PER_EVI)
                        strlcat(vtep_flag_str, "V", sizeof(vtep_flag_str));

                if (!strnlen(vtep_flag_str, sizeof(vtep_flag_str)))
                        strlcpy(vtep_flag_str, "-", sizeof(vtep_flag_str));
                if (first)
                        first = false;
                else
                        strlcat(vtep_str, ",", vtep_str_size);
                strlcat(vtep_str,
                        inet_ntop(AF_INET, &evi_vtep->vtep_ip, ip_buf,
                                  sizeof(ip_buf)),
                        vtep_str_size);
                strlcat(vtep_str, "(", vtep_str_size);
                strlcat(vtep_str, vtep_flag_str, vtep_str_size);
                strlcat(vtep_str, ")", vtep_str_size);
        }

        return vtep_str;
}

static void bgp_evpn_es_evi_json_vtep_fill(json_object *json_vteps,
                struct bgp_evpn_es_evi_vtep *evi_vtep)
{
        json_object *json_vtep_entry;
        json_object *json_flags;

        json_vtep_entry = json_object_new_object();

        json_object_string_addf(json_vtep_entry, "vtep_ip", "%pI4",
                                &evi_vtep->vtep_ip);
        if (evi_vtep->flags & (BGP_EVPN_EVI_VTEP_EAD_PER_ES |
                         BGP_EVPN_EVI_VTEP_EAD_PER_EVI)) {
                json_flags = json_object_new_array();
                if (evi_vtep->flags & BGP_EVPN_EVI_VTEP_EAD_PER_ES)
                        json_array_string_add(json_flags, "ead-per-es");
                if (evi_vtep->flags & BGP_EVPN_EVI_VTEP_EAD_PER_EVI)
                        json_array_string_add(json_flags, "ead-per-evi");
                json_object_object_add(json_vtep_entry,
                                "flags", json_flags);
        }

        json_object_array_add(json_vteps,
                        json_vtep_entry);
}

static void bgp_evpn_es_evi_show_entry(struct vty *vty,
                struct bgp_evpn_es_evi *es_evi, json_object *json)
{
        struct listnode *node;
        struct bgp_evpn_es_evi_vtep *evi_vtep;

        if (json) {
                json_object *json_vteps;
                json_object *json_types;

                json_object_string_add(json, "esi", es_evi->es->esi_str);
                json_object_int_add(json, "vni", es_evi->vpn->vni);

                if (es_evi->flags & (BGP_EVPNES_EVI_LOCAL |
                                        BGP_EVPNES_EVI_REMOTE)) {
                        json_types = json_object_new_array();
                        if (es_evi->flags & BGP_EVPNES_EVI_LOCAL)
                                json_array_string_add(json_types, "local");
                        if (es_evi->flags & BGP_EVPNES_EVI_REMOTE)
                                json_array_string_add(json_types, "remote");
                        json_object_object_add(json, "type", json_types);
                }

                if (listcount(es_evi->es_evi_vtep_list)) {
                        json_vteps = json_object_new_array();
                        for (ALL_LIST_ELEMENTS_RO(es_evi->es_evi_vtep_list,
                                                node, evi_vtep)) {
                                bgp_evpn_es_evi_json_vtep_fill(json_vteps,
                                                evi_vtep);
                        }
                        json_object_object_add(json, "vteps", json_vteps);
                }
        } else {
                char type_str[4];
                char vtep_str[ES_VTEP_LIST_STR_SZ + BGP_EVPN_VTEPS_FLAG_STR_SZ];

                type_str[0] = '\0';
                if (es_evi->flags & BGP_EVPNES_EVI_LOCAL)
                        strlcat(type_str, "L", sizeof(type_str));
                if (es_evi->flags & BGP_EVPNES_EVI_REMOTE)
                        strlcat(type_str, "R", sizeof(type_str));
                if (es_evi->flags & BGP_EVPNES_EVI_INCONS_VTEP_LIST)
                        strlcat(type_str, "I", sizeof(type_str));

                bgp_evpn_es_evi_vteps_str(vtep_str, es_evi, sizeof(vtep_str));

                vty_out(vty, "%-8d %-30s %-5s %s\n",
                                es_evi->vpn->vni, es_evi->es->esi_str,
                                type_str, vtep_str);
        }
}

static void bgp_evpn_es_evi_show_entry_detail(struct vty *vty,
                struct bgp_evpn_es_evi *es_evi, json_object *json)
{
        char buf1[RD_ADDRSTRLEN];

        if (json) {
                json_object *json_flags;

                /* Add the "brief" info first */
                bgp_evpn_es_evi_show_entry(vty, es_evi, json);
                if (es_evi->es_frag)
                        json_object_string_add(
                                json, "esFragmentRd",
                                prefix_rd2str(&es_evi->es_frag->prd, buf1,
                                              sizeof(buf1)));
                if (es_evi->flags & BGP_EVPNES_EVI_INCONS_VTEP_LIST) {
                        json_flags = json_object_new_array();
                        json_array_string_add(json_flags, "es-vtep-mismatch");
                        json_object_object_add(json, "flags", json_flags);
                }
        } else {
                char vtep_str[ES_VTEP_LIST_STR_SZ + BGP_EVPN_VTEPS_FLAG_STR_SZ];
                char type_str[4];

                type_str[0] = '\0';
                if (es_evi->flags & BGP_EVPNES_EVI_LOCAL)
                        strlcat(type_str, "L", sizeof(type_str));
                if (es_evi->flags & BGP_EVPNES_EVI_REMOTE)
                        strlcat(type_str, "R", sizeof(type_str));

                bgp_evpn_es_evi_vteps_str(vtep_str, es_evi, sizeof(vtep_str));
                if (!strlen(vtep_str))
                        strlcpy(vtep_str, "-", sizeof(type_str));

                vty_out(vty, "VNI: %d ESI: %s\n",
                                es_evi->vpn->vni, es_evi->es->esi_str);
                vty_out(vty, " Type: %s\n", type_str);
                if (es_evi->es_frag)
                        vty_out(vty, " ES fragment RD: %s\n",
                                prefix_rd2str(&es_evi->es_frag->prd, buf1,
                                              sizeof(buf1)));
                vty_out(vty, " Inconsistencies: %s\n",
                        (es_evi->flags & BGP_EVPNES_EVI_INCONS_VTEP_LIST) ?
                        "es-vtep-mismatch":"-");
                vty_out(vty, " VTEPs: %s\n", vtep_str);
                vty_out(vty, "\n");
        }
}

static void bgp_evpn_es_evi_show_one_vni(struct bgpevpn *vpn, struct vty *vty,
                json_object *json_array, bool detail)
{
        struct bgp_evpn_es_evi *es_evi;
        json_object *json = NULL;

        RB_FOREACH(es_evi, bgp_es_evi_rb_head, &vpn->es_evi_rb_tree) {
                if (json_array)
                        /* create a separate json object for each ES */
                        json = json_object_new_object();
                if (detail)
                        bgp_evpn_es_evi_show_entry_detail(vty, es_evi, json);
                else
                        bgp_evpn_es_evi_show_entry(vty, es_evi, json);
                /* add ES to the json array */
                if (json_array)
                        json_object_array_add(json_array, json);
        }
}

struct es_evi_show_ctx {
        struct vty *vty;
        json_object *json;
        int detail;
};

static void bgp_evpn_es_evi_show_one_vni_hash_cb(struct hash_bucket *bucket,
                void *ctxt)
{
        struct bgpevpn *vpn = (struct bgpevpn *)bucket->data;
        struct es_evi_show_ctx *wctx = (struct es_evi_show_ctx *)ctxt;

        bgp_evpn_es_evi_show_one_vni(vpn, wctx->vty, wctx->json, wctx->detail);
}

/* Display all ES EVIs */
void bgp_evpn_es_evi_show(struct vty *vty, bool uj, bool detail)
{
        json_object *json_array = NULL;
        struct es_evi_show_ctx wctx;
        struct bgp *bgp;

        if (uj) {
                /* create an array of ES-EVIs */
                json_array = json_object_new_array();
        }

        wctx.vty = vty;
        wctx.json = json_array;
        wctx.detail = detail;

        bgp = bgp_get_evpn();

        if (!json_array && !detail) {
                vty_out(vty, "Flags: L local, R remote, I inconsistent\n");
                vty_out(vty, "VTEP-Flags: E EAD-per-ES, V EAD-per-EVI\n");
                vty_out(vty, "%-8s %-30s %-5s %s\n",
                                "VNI", "ESI", "Flags", "VTEPs");
        }

        if (bgp)
                hash_iterate(bgp->vnihash,
                                (void (*)(struct hash_bucket *,
                                  void *))bgp_evpn_es_evi_show_one_vni_hash_cb,
                                &wctx);
        if (uj)
                vty_json(vty, json_array);
}

/* Display specific ES EVI */
void bgp_evpn_es_evi_show_vni(struct vty *vty, vni_t vni,
                bool uj, bool detail)
{
        struct bgpevpn *vpn = NULL;
        json_object *json_array = NULL;
        struct bgp *bgp;

        if (uj) {
                /* create an array of ES-EVIs */
                json_array = json_object_new_array();
        }

        bgp = bgp_get_evpn();
        if (bgp)
                vpn = bgp_evpn_lookup_vni(bgp, vni);

        if (vpn) {
                if (!json_array && !detail) {
                        vty_out(vty, "Flags: L local, R remote, I inconsistent\n");
                        vty_out(vty, "VTEP-Flags: E EAD-per-ES, V EAD-per-EVI\n");
                        vty_out(vty, "%-8s %-30s %-5s %s\n",
                                        "VNI", "ESI", "Flags", "VTEPs");
                }

                bgp_evpn_es_evi_show_one_vni(vpn, vty, json_array, detail);
        } else {
                if (!uj)
                        vty_out(vty, "VNI not found\n");
        }

        if (uj)
                vty_json(vty, json_array);
}

/*****************************************************************************
 * Ethernet Segment Consistency checks
 *     Consistency checking is done to detect misconfig or mis-cabling. When
 * an inconsistency is detected it is simply logged (and displayed via
 * show commands) at this point. A more drastic action can be executed (based
 * on user config) in the future.
 */
static void bgp_evpn_es_cons_checks_timer_start(void)
{
        if (!bgp_mh_info->consistency_checking || bgp_mh_info->t_cons_check)
                return;

        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug("periodic consistency checking started");

        thread_add_timer(bm->master, bgp_evpn_run_consistency_checks, NULL,
                         BGP_EVPN_CONS_CHECK_INTERVAL,
                         &bgp_mh_info->t_cons_check);
}

/* queue up the es for background consistency checks */
static void bgp_evpn_es_cons_checks_pend_add(struct bgp_evpn_es *es)
{
        if (!bgp_mh_info->consistency_checking)
                /* consistency checking is not enabled */
                return;

        if (CHECK_FLAG(es->flags, BGP_EVPNES_CONS_CHECK_PEND))
                /* already queued for consistency checking */
                return;

        /* start the periodic timer for consistency checks if it is not
         * already running */
        bgp_evpn_es_cons_checks_timer_start();

        SET_FLAG(es->flags, BGP_EVPNES_CONS_CHECK_PEND);
        listnode_init(&es->pend_es_listnode, es);
        listnode_add_after(bgp_mh_info->pend_es_list,
                        listtail_unchecked(bgp_mh_info->pend_es_list),
                        &es->pend_es_listnode);
}

/* pull the ES from the consistency check list */
static void bgp_evpn_es_cons_checks_pend_del(struct bgp_evpn_es *es)
{
        if (!CHECK_FLAG(es->flags, BGP_EVPNES_CONS_CHECK_PEND))
                return;

        UNSET_FLAG(es->flags, BGP_EVPNES_CONS_CHECK_PEND);
        list_delete_node(bgp_mh_info->pend_es_list,
                        &es->pend_es_listnode);
}

/* Number of active VTEPs associated with the ES-per-EVI */
static uint32_t bgp_evpn_es_evi_get_active_vtep_cnt(
                struct bgp_evpn_es_evi *es_evi)
{
        struct bgp_evpn_es_evi_vtep *evi_vtep;
        struct listnode *node;
        uint32_t vtep_cnt = 0;

        for (ALL_LIST_ELEMENTS_RO(es_evi->es_evi_vtep_list, node, evi_vtep)) {
                if (CHECK_FLAG(evi_vtep->flags, BGP_EVPN_EVI_VTEP_ACTIVE))
                        ++vtep_cnt;
        }

        return vtep_cnt;
}

/* Number of active VTEPs associated with the ES */
static uint32_t bgp_evpn_es_get_active_vtep_cnt(struct bgp_evpn_es *es)
{
        struct listnode *node;
        uint32_t vtep_cnt = 0;
        struct bgp_evpn_es_vtep *es_vtep;

        for (ALL_LIST_ELEMENTS_RO(es->es_vtep_list, node, es_vtep)) {
                if (CHECK_FLAG(es_vtep->flags, BGP_EVPNES_VTEP_ACTIVE))
                        ++vtep_cnt;
        }

        return vtep_cnt;
}

static struct bgp_evpn_es_vtep *bgp_evpn_es_get_next_active_vtep(
                struct bgp_evpn_es *es, struct bgp_evpn_es_vtep *es_vtep)
{
        struct listnode *node;
        struct bgp_evpn_es_vtep *next_es_vtep;

        if (es_vtep)
                node = listnextnode_unchecked(&es_vtep->es_listnode);
        else
                node = listhead(es->es_vtep_list);

        for (; node; node = listnextnode_unchecked(node)) {
                next_es_vtep = listgetdata(node);
                if (CHECK_FLAG(next_es_vtep->flags, BGP_EVPNES_VTEP_ACTIVE))
                        return next_es_vtep;
        }

        return NULL;
}

static struct bgp_evpn_es_evi_vtep *bgp_evpn_es_evi_get_next_active_vtep(
        struct bgp_evpn_es_evi *es_evi,
        struct bgp_evpn_es_evi_vtep *evi_vtep)
{
        struct listnode *node;
        struct bgp_evpn_es_evi_vtep *next_evi_vtep;

        if (evi_vtep)
                node = listnextnode_unchecked(&evi_vtep->es_evi_listnode);
        else
                node = listhead(es_evi->es_evi_vtep_list);

        for (; node; node = listnextnode_unchecked(node)) {
                next_evi_vtep = listgetdata(node);
                if (CHECK_FLAG(next_evi_vtep->flags, BGP_EVPN_EVI_VTEP_ACTIVE))
                        return next_evi_vtep;
        }

        return NULL;
}

static void bgp_evpn_es_evi_set_inconsistent(struct bgp_evpn_es_evi *es_evi)
{
        if (!CHECK_FLAG(es_evi->flags, BGP_EVPNES_EVI_INCONS_VTEP_LIST)) {
                if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                        zlog_debug("inconsistency detected - es %s evi %u vtep list mismatch",
                                        es_evi->es->esi_str,
                                        es_evi->vpn->vni);
                SET_FLAG(es_evi->flags, BGP_EVPNES_EVI_INCONS_VTEP_LIST);

                /* update parent ES with the incosistency setting */
                if (!es_evi->es->incons_evi_vtep_cnt &&
                                BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                        zlog_debug("inconsistency detected - es %s vtep list mismatch",
                                        es_evi->es->esi_str);
                ++es_evi->es->incons_evi_vtep_cnt;
                SET_FLAG(es_evi->es->inconsistencies,
                                BGP_EVPNES_INCONS_VTEP_LIST);
        }
}

static uint32_t bgp_evpn_es_run_consistency_checks(struct bgp_evpn_es *es)
{
        int proc_cnt = 0;
        int es_active_vtep_cnt;
        int evi_active_vtep_cnt;
        struct bgp_evpn_es_evi *es_evi;
        struct listnode *evi_node;
        struct bgp_evpn_es_vtep *es_vtep;
        struct bgp_evpn_es_evi_vtep *evi_vtep;

        /* reset the inconsistencies and re-evaluate */
        es->incons_evi_vtep_cnt = 0;
        es->inconsistencies = 0;

        es_active_vtep_cnt = bgp_evpn_es_get_active_vtep_cnt(es);
        for (ALL_LIST_ELEMENTS_RO(es->es_evi_list,
                                evi_node, es_evi)) {
                ++proc_cnt;

                /* reset the inconsistencies on the EVI and re-evaluate*/
                UNSET_FLAG(es_evi->flags, BGP_EVPNES_EVI_INCONS_VTEP_LIST);

                evi_active_vtep_cnt =
                        bgp_evpn_es_evi_get_active_vtep_cnt(es_evi);
                if (es_active_vtep_cnt != evi_active_vtep_cnt) {
                        bgp_evpn_es_evi_set_inconsistent(es_evi);
                        continue;
                }

                if (!es_active_vtep_cnt)
                        continue;

                es_vtep = NULL;
                evi_vtep = NULL;
                while ((es_vtep = bgp_evpn_es_get_next_active_vtep(
                                                es, es_vtep))) {
                        evi_vtep = bgp_evpn_es_evi_get_next_active_vtep(es_evi,
                                        evi_vtep);
                        if (!evi_vtep) {
                                bgp_evpn_es_evi_set_inconsistent(es_evi);
                                break;
                        }
                        if (es_vtep->vtep_ip.s_addr !=
                                        evi_vtep->vtep_ip.s_addr) {
                                /* inconsistency detected; set it and move
                                 * to the next evi
                                 */
                                bgp_evpn_es_evi_set_inconsistent(es_evi);
                                break;
                        }
                }
        }

        return proc_cnt;
}

static void bgp_evpn_run_consistency_checks(struct thread *t)
{
        int proc_cnt = 0;
        int es_cnt = 0;
        struct listnode *node;
        struct listnode *nextnode;
        struct bgp_evpn_es *es;

        for (ALL_LIST_ELEMENTS(bgp_mh_info->pend_es_list,
                                node, nextnode, es)) {
                ++es_cnt;
                ++proc_cnt;
                /* run consistency checks on the ES and remove it from the
                 * pending list
                 */
                proc_cnt += bgp_evpn_es_run_consistency_checks(es);
                bgp_evpn_es_cons_checks_pend_del(es);
                if (proc_cnt > 500)
                        break;
        }

        /* restart the timer */
        thread_add_timer(bm->master, bgp_evpn_run_consistency_checks, NULL,
                        BGP_EVPN_CONS_CHECK_INTERVAL,
                        &bgp_mh_info->t_cons_check);
}

/*****************************************************************************
 * EVPN-Nexthop and RMAC management: nexthops associated with Type-2 routes
 * that have an ES as destination are consolidated by BGP into a per-VRF
 * nh->rmac mapping which is sent to zebra. Zebra installs the nexthop
 * as a remote neigh/fdb entry with a dummy (type-1) prefix referencing it.
 *
 * This handling is needed because Type-2 routes with ES as dest use NHG
 * that is setup using EAD routes (i.e. such NHGs do not include the
 * RMAC info).
 ****************************************************************************/
static void bgp_evpn_nh_zebra_update_send(struct bgp_evpn_nh *nh, bool add)
{
        struct stream *s;
        struct bgp *bgp_vrf = nh->bgp_vrf;

        /* Check socket. */
        if (!zclient || zclient->sock < 0)
                return;

        /* Don't try to register if Zebra doesn't know of this instance. */
        if (!IS_BGP_INST_KNOWN_TO_ZEBRA(bgp_vrf)) {
                if (BGP_DEBUG(zebra, ZEBRA))
                        zlog_debug("No zebra instance, not %s remote nh %s",
                                   add ? "adding" : "deleting", nh->nh_str);
                return;
        }

        s = zclient->obuf;
        stream_reset(s);

        zclient_create_header(
                s, add ? ZEBRA_EVPN_REMOTE_NH_ADD : ZEBRA_EVPN_REMOTE_NH_DEL,
                bgp_vrf->vrf_id);
        stream_putl(s, bgp_vrf->vrf_id);
        stream_put(s, &nh->ip, sizeof(nh->ip));
        if (add)
                stream_put(s, &nh->rmac, sizeof(nh->rmac));

        stream_putw_at(s, 0, stream_get_endp(s));

        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES)) {
                if (add)
                        zlog_debug("evpn vrf %s nh %s rmac %pEA add to zebra",
                                   nh->bgp_vrf->name, nh->nh_str, &nh->rmac);
                else if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                        zlog_debug("evpn vrf %s nh %s del to zebra",
                                   nh->bgp_vrf->name, nh->nh_str);
        }

        frrtrace(2, frr_bgp, evpn_mh_nh_rmac_zsend, add, nh);

        zclient_send_message(zclient);
}

static void bgp_evpn_nh_zebra_update(struct bgp_evpn_nh *nh, bool add)
{
        if (add && !is_zero_mac(&nh->rmac)) {
                nh->flags |= BGP_EVPN_NH_READY_FOR_ZEBRA;
                bgp_evpn_nh_zebra_update_send(nh, true);
        } else {
                if (!(nh->flags & BGP_EVPN_NH_READY_FOR_ZEBRA))
                        return;
                nh->flags &= ~BGP_EVPN_NH_READY_FOR_ZEBRA;
                bgp_evpn_nh_zebra_update_send(nh, false);
        }
}

static void *bgp_evpn_nh_alloc(void *p)
{
        struct bgp_evpn_nh *tmp_n = p;
        struct bgp_evpn_nh *n;

        n = XCALLOC(MTYPE_BGP_EVPN_NH, sizeof(struct bgp_evpn_nh));
        *n = *tmp_n;

        return ((void *)n);
}

static struct bgp_evpn_nh *bgp_evpn_nh_find(struct bgp *bgp_vrf,
                                            struct ipaddr *ip)
{
        struct bgp_evpn_nh tmp;
        struct bgp_evpn_nh *n;

        memset(&tmp, 0, sizeof(tmp));
        memcpy(&tmp.ip, ip, sizeof(struct ipaddr));
        n = hash_lookup(bgp_vrf->evpn_nh_table, &tmp);

        return n;
}

/* Add nexthop entry - implicitly created on first path reference */
static struct bgp_evpn_nh *bgp_evpn_nh_add(struct bgp *bgp_vrf,
                                           struct ipaddr *ip,
                                           struct bgp_path_info *pi)
{
        struct bgp_evpn_nh tmp_n;
        struct bgp_evpn_nh *n = NULL;

        memset(&tmp_n, 0, sizeof(struct bgp_evpn_nh));
        memcpy(&tmp_n.ip, ip, sizeof(struct ipaddr));
        n = hash_get(bgp_vrf->evpn_nh_table, &tmp_n, bgp_evpn_nh_alloc);
        ipaddr2str(ip, n->nh_str, sizeof(n->nh_str));
        n->bgp_vrf = bgp_vrf;

        n->pi_list = list_new();
        listset_app_node_mem(n->pi_list);

        /* Setup ref_pi when the nh is created */
        if (CHECK_FLAG(pi->flags, BGP_PATH_VALID) && pi->attr) {
                n->ref_pi = pi;
                memcpy(&n->rmac, &pi->attr->rmac, ETH_ALEN);
        }

        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug("evpn vrf %s nh %s rmac %pEA add", n->bgp_vrf->name,
                           n->nh_str, &n->rmac);
        bgp_evpn_nh_zebra_update(n, true);
        return n;
}

/* Delete nexthop entry if there are no paths referencing it */
static void bgp_evpn_nh_del(struct bgp_evpn_nh *n)
{
        struct bgp_evpn_nh *tmp_n;
        struct bgp *bgp_vrf = n->bgp_vrf;

        if (listcount(n->pi_list))
                return;

        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug("evpn vrf %s nh %s del to zebra", bgp_vrf->name,
                           n->nh_str);

        bgp_evpn_nh_zebra_update(n, false);
        list_delete(&n->pi_list);
        tmp_n = hash_release(bgp_vrf->evpn_nh_table, n);
        XFREE(MTYPE_BGP_EVPN_NH, tmp_n);
}

static unsigned int bgp_evpn_nh_hash_keymake(const void *p)
{
        const struct bgp_evpn_nh *n = p;
        const struct ipaddr *ip = &n->ip;

        if (IS_IPADDR_V4(ip))
                return jhash_1word(ip->ipaddr_v4.s_addr, 0);

        return jhash2(ip->ipaddr_v6.s6_addr32,
                      array_size(ip->ipaddr_v6.s6_addr32), 0);
}

static bool bgp_evpn_nh_cmp(const void *p1, const void *p2)
{
        const struct bgp_evpn_nh *n1 = p1;
        const struct bgp_evpn_nh *n2 = p2;

        if (n1 == NULL && n2 == NULL)
                return true;

        if (n1 == NULL || n2 == NULL)
                return false;

        return (ipaddr_cmp(&n1->ip, &n2->ip) == 0);
}

void bgp_evpn_nh_init(struct bgp *bgp_vrf)
{
        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug("evpn vrf %s nh init", bgp_vrf->name);
        bgp_vrf->evpn_nh_table = hash_create(
                bgp_evpn_nh_hash_keymake, bgp_evpn_nh_cmp, "BGP EVPN NH table");
}

static void bgp_evpn_nh_flush_entry(struct bgp_evpn_nh *nh)
{
        struct listnode *node;
        struct listnode *nnode;
        struct bgp_path_evpn_nh_info *nh_info;

        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug("evpn vrf %s nh %s flush", nh->bgp_vrf->name,
                           nh->nh_str);

        /* force flush paths */
        for (ALL_LIST_ELEMENTS(nh->pi_list, node, nnode, nh_info))
                bgp_evpn_path_nh_del(nh->bgp_vrf, nh_info->pi);
}

static void bgp_evpn_nh_flush_cb(struct hash_bucket *bucket, void *ctxt)
{
        struct bgp_evpn_nh *nh = (struct bgp_evpn_nh *)bucket->data;

        bgp_evpn_nh_flush_entry(nh);
}

void bgp_evpn_nh_finish(struct bgp *bgp_vrf)
{
        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug("evpn vrf %s nh finish", bgp_vrf->name);
        hash_iterate(
                bgp_vrf->evpn_nh_table,
                (void (*)(struct hash_bucket *, void *))bgp_evpn_nh_flush_cb,
                NULL);
        hash_free(bgp_vrf->evpn_nh_table);
        bgp_vrf->evpn_nh_table = NULL;
}

static void bgp_evpn_nh_update_ref_pi(struct bgp_evpn_nh *nh)
{
        struct listnode *node;
        struct bgp_path_info *pi;
        struct bgp_path_evpn_nh_info *nh_info;

        if (nh->ref_pi)
                return;

        for (ALL_LIST_ELEMENTS_RO(nh->pi_list, node, nh_info)) {
                pi = nh_info->pi;
                if (!CHECK_FLAG(pi->flags, BGP_PATH_VALID) || !pi->attr)
                        continue;

                if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                        zlog_debug("evpn vrf %s nh %s ref_pi update",
                                   nh->bgp_vrf->name, nh->nh_str);
                nh->ref_pi = pi;
                /* If we have a new pi copy rmac from it and update
                 * zebra if the new rmac is different
                 */
                if (memcmp(&nh->rmac, &nh->ref_pi->attr->rmac, ETH_ALEN)) {
                        memcpy(&nh->rmac, &nh->ref_pi->attr->rmac, ETH_ALEN);
                        bgp_evpn_nh_zebra_update(nh, true);
                }
                break;
        }
}

static void bgp_evpn_nh_clear_ref_pi(struct bgp_evpn_nh *nh,
                                     struct bgp_path_info *pi)
{
        if (nh->ref_pi != pi)
                return;

        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES))
                zlog_debug("evpn vrf %s nh %s ref_pi clear", nh->bgp_vrf->name,
                           nh->nh_str);
        nh->ref_pi = NULL;
        /* try to find another ref_pi */
        bgp_evpn_nh_update_ref_pi(nh);
        /* couldn't find one - clear the old rmac and notify zebra */
        if (!nh->ref_pi) {
                memset(&nh->rmac, 0, ETH_ALEN);
                bgp_evpn_nh_zebra_update(nh, true);
        }
}

static void bgp_evpn_path_nh_info_free(struct bgp_path_evpn_nh_info *nh_info)
{
        bgp_evpn_path_nh_unlink(nh_info);
        XFREE(MTYPE_BGP_EVPN_PATH_NH_INFO, nh_info);
}

static struct bgp_path_evpn_nh_info *
bgp_evpn_path_nh_info_new(struct bgp_path_info *pi)
{
        struct bgp_path_info_extra *e;
        struct bgp_path_mh_info *mh_info;
        struct bgp_path_evpn_nh_info *nh_info;

        e = bgp_path_info_extra_get(pi);

        /* If mh_info doesn't exist allocate it */
        mh_info = e->mh_info;
        if (!mh_info)
                e->mh_info = mh_info = XCALLOC(MTYPE_BGP_EVPN_PATH_MH_INFO,
                                               sizeof(struct bgp_path_mh_info));

        /* If nh_info doesn't exist allocate it */
        nh_info = mh_info->nh_info;
        if (!nh_info) {
                mh_info->nh_info = nh_info =
                        XCALLOC(MTYPE_BGP_EVPN_PATH_NH_INFO,
                                sizeof(struct bgp_path_evpn_nh_info));
                nh_info->pi = pi;
        }

        return nh_info;
}

static void bgp_evpn_path_nh_unlink(struct bgp_path_evpn_nh_info *nh_info)
{
        struct bgp_evpn_nh *nh = nh_info->nh;
        struct bgp_path_info *pi;
        char prefix_buf[PREFIX_STRLEN];

        if (!nh)
                return;

        pi = nh_info->pi;
        if (BGP_DEBUG(evpn_mh, EVPN_MH_RT))
                zlog_debug("path %s unlinked from nh %s %s",
                           pi->net ? prefix2str(&pi->net->p, prefix_buf,
                                                sizeof(prefix_buf))
                                   : "",
                           nh->bgp_vrf->name, nh->nh_str);

        list_delete_node(nh->pi_list, &nh_info->nh_listnode);

        nh_info->nh = NULL;

        /* check if the ref_pi need to be updated */
        bgp_evpn_nh_clear_ref_pi(nh, pi);

        /* if there are no other references against the nh it
         * needs to be freed
         */
        bgp_evpn_nh_del(nh);

        /* Note we don't free the path nh_info on unlink; it will be freed up
         * along with the path.
         */
}

static void bgp_evpn_path_nh_link(struct bgp *bgp_vrf, struct bgp_path_info *pi)
{
        struct bgp_path_evpn_nh_info *nh_info;
        struct bgp_evpn_nh *nh;
        struct ipaddr ip;

        /* EVPN nexthop setup in bgp has been turned off */
        if (!bgp_mh_info->bgp_evpn_nh_setup)
                return;

        if (!bgp_vrf->evpn_nh_table) {
                if (BGP_DEBUG(evpn_mh, EVPN_MH_RT))
                        zlog_debug("path %pFX linked to vrf %s failed",
                                   &pi->net->p, bgp_vrf->name);
                return;
        }

        nh_info = (pi->extra && pi->extra->mh_info)
                          ? pi->extra->mh_info->nh_info
                          : NULL;

        /* if NHG is not being used for this path we don't need to manage the
         * nexthops in bgp (they are managed by zebra instead)
         */
        if (!(pi->attr->es_flags & ATTR_ES_L3_NHG_USE)) {
                if (nh_info)
                        bgp_evpn_path_nh_unlink(nh_info);
                return;
        }

        /* setup nh_info against the path if it doesn't aleady exist */
        if (!nh_info)
                nh_info = bgp_evpn_path_nh_info_new(pi);

        /* find-create nh */
        memset(&ip, 0, sizeof(ip));
        if (pi->net->p.family == AF_INET6) {
                SET_IPADDR_V6(&ip);
                memcpy(&ip.ipaddr_v6, &pi->attr->mp_nexthop_global,
                       sizeof(ip.ipaddr_v6));
        } else {
                SET_IPADDR_V4(&ip);
                memcpy(&ip.ipaddr_v4, &pi->attr->nexthop, sizeof(ip.ipaddr_v4));
        }

        nh = bgp_evpn_nh_find(bgp_vrf, &ip);
        if (!nh)
                nh = bgp_evpn_nh_add(bgp_vrf, &ip, pi);

        /* dup check */
        if (nh_info->nh == nh) {
                /* Check if any of the paths are now valid */
                bgp_evpn_nh_update_ref_pi(nh);
                return;
        }

        /* unlink old nh if any */
        bgp_evpn_path_nh_unlink(nh_info);

        if (BGP_DEBUG(evpn_mh, EVPN_MH_RT))
                zlog_debug("path %pFX linked to nh %s %s", &pi->net->p,
                           nh->bgp_vrf->name, nh->nh_str);

        /* link mac-ip path to the new nh */
        nh_info->nh = nh;
        listnode_init(&nh_info->nh_listnode, nh_info);
        listnode_add(nh->pi_list, &nh_info->nh_listnode);
        /* If a new valid path got linked to the nh see if can get the rmac
         * from it
         */
        bgp_evpn_nh_update_ref_pi(nh);
        if (BGP_DEBUG(evpn_mh, EVPN_MH_ES)) {
                if (!nh->ref_pi)
                        zlog_debug(
                                "path %pFX linked to nh %s %s with no valid pi",
                                &pi->net->p, nh->bgp_vrf->name, nh->nh_str);
        }
}

void bgp_evpn_path_nh_del(struct bgp *bgp_vrf, struct bgp_path_info *pi)
{
        struct bgp_path_evpn_nh_info *nh_info;

        nh_info = (pi->extra && pi->extra->mh_info)
                          ? pi->extra->mh_info->nh_info
                          : NULL;

        if (!nh_info)
                return;

        bgp_evpn_path_nh_unlink(nh_info);
}

void bgp_evpn_path_nh_add(struct bgp *bgp_vrf, struct bgp_path_info *pi)
{
        bgp_evpn_path_nh_link(bgp_vrf, pi);
}

static void bgp_evpn_nh_show_entry(struct bgp_evpn_nh *nh, struct vty *vty,
                                   json_object *json_array)
{
        json_object *json = NULL;
        char mac_buf[ETHER_ADDR_STRLEN];
        char prefix_buf[PREFIX_STRLEN];

        if (json_array)
                /* create a separate json object for each ES */
                json = json_object_new_object();

        prefix_mac2str(&nh->rmac, mac_buf, sizeof(mac_buf));
        if (nh->ref_pi && nh->ref_pi->net)
                prefix2str(&nh->ref_pi->net->p, prefix_buf, sizeof(prefix_buf));
        else
                prefix_buf[0] = '\0';
        if (json) {
                json_object_string_add(json, "vrf", nh->bgp_vrf->name);
                json_object_string_add(json, "ip", nh->nh_str);
                json_object_string_add(json, "rmac", mac_buf);
                json_object_string_add(json, "basePath", prefix_buf);
                json_object_int_add(json, "pathCount", listcount(nh->pi_list));
        } else {
                vty_out(vty, "%-15s %-15s %-17s %-10d %s\n", nh->bgp_vrf->name,
                        nh->nh_str, mac_buf, listcount(nh->pi_list),
                        prefix_buf);
        }

        /* add ES to the json array */
        if (json_array)
                json_object_array_add(json_array, json);
}

struct nh_show_ctx {
        struct vty *vty;
        json_object *json;
};

static void bgp_evpn_nh_show_hash_cb(struct hash_bucket *bucket, void *ctxt)
{
        struct bgp_evpn_nh *nh = (struct bgp_evpn_nh *)bucket->data;
        struct nh_show_ctx *wctx = (struct nh_show_ctx *)ctxt;

        bgp_evpn_nh_show_entry(nh, wctx->vty, wctx->json);
}

/* Display all evpn nexthops */
void bgp_evpn_nh_show(struct vty *vty, bool uj)
{
        json_object *json_array = NULL;
        struct bgp *bgp_vrf;
        struct listnode *node;
        struct nh_show_ctx wctx;

        if (uj) {
                /* create an array of nexthops */
                json_array = json_object_new_array();
        } else {
                vty_out(vty, "%-15s %-15s %-17s %-10s %s\n", "VRF", "IP",
                        "RMAC", "#Paths", "Base Path");
        }

        wctx.vty = vty;
        wctx.json = json_array;

        /* walk through all vrfs */
        for (ALL_LIST_ELEMENTS_RO(bm->bgp, node, bgp_vrf)) {
                hash_iterate(bgp_vrf->evpn_nh_table,
                             (void (*)(struct hash_bucket *,
                                       void *))bgp_evpn_nh_show_hash_cb,
                             &wctx);
        }

        /* print the array of json-ESs */
        if (uj)
                vty_json(vty, json_array);
}

/*****************************************************************************/
void bgp_evpn_mh_init(void)
{
        bm->mh_info = XCALLOC(MTYPE_BGP_EVPN_MH_INFO, sizeof(*bm->mh_info));

        /* setup ES tables */
        RB_INIT(bgp_es_rb_head, &bgp_mh_info->es_rb_tree);
        /* local ES list */
        bgp_mh_info->local_es_list = list_new();
        listset_app_node_mem(bgp_mh_info->local_es_list);
        /* list of ESs with pending processing */
        bgp_mh_info->pend_es_list = list_new();
        listset_app_node_mem(bgp_mh_info->pend_es_list);

        bgp_mh_info->ead_evi_rx = BGP_EVPN_MH_EAD_EVI_RX_DEF;
        bgp_mh_info->ead_evi_tx = BGP_EVPN_MH_EAD_EVI_TX_DEF;
        bgp_mh_info->ead_es_export_rtl = list_new();
        bgp_mh_info->ead_es_export_rtl->cmp =
                (int (*)(void *, void *))bgp_evpn_route_target_cmp;
        bgp_mh_info->ead_es_export_rtl->del = bgp_evpn_xxport_delete_ecomm;

        /* config knobs - XXX add cli to control it */
        bgp_mh_info->ead_evi_adv_for_down_links = true;
        bgp_mh_info->consistency_checking = true;
        bgp_mh_info->install_l3nhg = false;
        bgp_mh_info->host_routes_use_l3nhg = BGP_EVPN_MH_USE_ES_L3NHG_DEF;
        bgp_mh_info->suppress_l3_ecomm_on_inactive_es = true;
        bgp_mh_info->bgp_evpn_nh_setup = true;
        bgp_mh_info->evi_per_es_frag = BGP_EVPN_MAX_EVI_PER_ES_FRAG;

        memset(&zero_esi_buf, 0, sizeof(esi_t));
}

void bgp_evpn_mh_finish(void)
{
        struct bgp_evpn_es *es;
        struct bgp_evpn_es *es_next;

        if (BGP_DEBUG(evpn_mh, EVPN_MH_RT))
                zlog_debug("evpn mh finish");

        RB_FOREACH_SAFE (es, bgp_es_rb_head, &bgp_mh_info->es_rb_tree,
                         es_next) {
                bgp_evpn_es_local_info_clear(es, true);
        }
        if (bgp_mh_info->t_cons_check)
                thread_cancel(&bgp_mh_info->t_cons_check);
        list_delete(&bgp_mh_info->local_es_list);
        list_delete(&bgp_mh_info->pend_es_list);
        list_delete(&bgp_mh_info->ead_es_export_rtl);

        XFREE(MTYPE_BGP_EVPN_MH_INFO, bgp_mh_info);
}

/* This function is called when disable-ead-evi-rx knob flaps */
void bgp_evpn_switch_ead_evi_rx(void)
{
        struct bgp *bgp;
        struct bgp_evpn_es *es;
        struct bgp_evpn_es_evi *es_evi;
        struct listnode *evi_node = NULL;
        struct listnode *evi_next = NULL;
        struct bgp_evpn_es_evi_vtep *vtep;
        struct listnode *vtep_node = NULL;
        struct listnode *vtep_next = NULL;

        bgp = bgp_get_evpn();
        if (!bgp)
                return;

        /*
         * Process all the remote es_evi_vteps and reevaluate if the es_evi_vtep
         * is active.
         */
        RB_FOREACH(es, bgp_es_rb_head, &bgp_mh_info->es_rb_tree) {
                if (!CHECK_FLAG(es->flags, BGP_EVPNES_REMOTE))
                        continue;

                for (ALL_LIST_ELEMENTS(es->es_evi_list, evi_node, evi_next,
                                       es_evi)) {
                        if (!CHECK_FLAG(es_evi->flags, BGP_EVPNES_EVI_REMOTE))
                                continue;

                        for (ALL_LIST_ELEMENTS(es_evi->es_evi_vtep_list,
                                               vtep_node, vtep_next, vtep))
                                bgp_evpn_es_evi_vtep_re_eval_active(bgp, vtep);
                }
        }
}