Merge pull request #9998 from pguibert6WIND/bgp_tcp_keepalive

[mirror_frr.git] / ospfd / ospf_interface.c

/*
 * OSPF Interface functions.
 * Copyright (C) 1999, 2000 Toshiaki Takada
 *
 * This file is part of GNU Zebra.
 *
 * GNU Zebra is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published
 * by the Free Software Foundation; either version 2, or (at your
 * option) any later version.
 *
 * GNU Zebra is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; see the file COPYING; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <zebra.h>

#include "thread.h"
#include "linklist.h"
#include "prefix.h"
#include "if.h"
#include "table.h"
#include "memory.h"
#include "command.h"
#include "stream.h"
#include "log.h"
#include "zclient.h"
#include "bfd.h"
#include "ldp_sync.h"

#include "ospfd/ospfd.h"
#include "ospfd/ospf_bfd.h"
#include "ospfd/ospf_spf.h"
#include "ospfd/ospf_interface.h"
#include "ospfd/ospf_ism.h"
#include "ospfd/ospf_asbr.h"
#include "ospfd/ospf_lsa.h"
#include "ospfd/ospf_lsdb.h"
#include "ospfd/ospf_neighbor.h"
#include "ospfd/ospf_nsm.h"
#include "ospfd/ospf_packet.h"
#include "ospfd/ospf_abr.h"
#include "ospfd/ospf_network.h"
#include "ospfd/ospf_dump.h"
#include "ospfd/ospf_ldp_sync.h"
#include "ospfd/ospf_route.h"
#include "ospfd/ospf_te.h"

DEFINE_QOBJ_TYPE(ospf_interface);
DEFINE_HOOK(ospf_vl_add, (struct ospf_vl_data * vd), (vd));
DEFINE_HOOK(ospf_vl_delete, (struct ospf_vl_data * vd), (vd));
DEFINE_HOOK(ospf_if_update, (struct interface * ifp), (ifp));
DEFINE_HOOK(ospf_if_delete, (struct interface * ifp), (ifp));

int ospf_interface_neighbor_count(struct ospf_interface *oi)
{
        int count = 0;
        struct route_node *rn;
        struct ospf_neighbor *nbr = NULL;

        for (rn = route_top(oi->nbrs); rn; rn = route_next(rn)) {
                nbr = rn->info;
                if (!nbr)
                        continue;

                /* Do not show myself. */
                if (nbr == oi->nbr_self)
                        continue;
                /* Down state is not shown. */
                if (nbr->state == NSM_Down)
                        continue;
                count++;
        }

        return count;
}

int ospf_if_get_output_cost(struct ospf_interface *oi)
{
        /* If all else fails, use default OSPF cost */
        uint32_t cost;
        uint32_t bw, refbw;

        /* if LDP-IGP Sync is running on interface set cost so interface
         * is used only as last resort
         */
        if (ldp_sync_if_is_enabled(IF_DEF_PARAMS(oi->ifp)->ldp_sync_info))
                return (LDP_OSPF_LSINFINITY);

        /* ifp speed and bw can be 0 in some platforms, use ospf default bw
           if bw is configured under interface it would be used.
         */
        if (!oi->ifp->bandwidth && oi->ifp->speed)
                bw = oi->ifp->speed;
        else
                bw = oi->ifp->bandwidth ? oi->ifp->bandwidth
                                        : OSPF_DEFAULT_BANDWIDTH;
        refbw = oi->ospf->ref_bandwidth;

        /* A specified ip ospf cost overrides a calculated one. */
        if (OSPF_IF_PARAM_CONFIGURED(IF_DEF_PARAMS(oi->ifp), output_cost_cmd)
            || OSPF_IF_PARAM_CONFIGURED(oi->params, output_cost_cmd))
                cost = OSPF_IF_PARAM(oi, output_cost_cmd);
        /* See if a cost can be calculated from the zebra processes
           interface bandwidth field. */
        else {
                cost = (uint32_t)((double)refbw / (double)bw + (double)0.5);
                if (cost < 1)
                        cost = 1;
                else if (cost > 65535)
                        cost = 65535;
        }

        return cost;
}

void ospf_if_recalculate_output_cost(struct interface *ifp)
{
        uint32_t newcost;
        struct route_node *rn;

        for (rn = route_top(IF_OIFS(ifp)); rn; rn = route_next(rn)) {
                struct ospf_interface *oi;

                if ((oi = rn->info) == NULL)
                        continue;

                newcost = ospf_if_get_output_cost(oi);

                /* Is actual output cost changed? */
                if (oi->output_cost != newcost) {
                        oi->output_cost = newcost;
                        ospf_router_lsa_update_area(oi->area);
                }
        }
}

/* Simulate down/up on the interface.  This is needed, for example, when
   the MTU changes. */
void ospf_if_reset(struct interface *ifp)
{
        struct route_node *rn;

        for (rn = route_top(IF_OIFS(ifp)); rn; rn = route_next(rn)) {
                struct ospf_interface *oi;

                if ((oi = rn->info) == NULL)
                        continue;

                ospf_if_down(oi);
                ospf_if_up(oi);
        }
}

void ospf_if_reset_variables(struct ospf_interface *oi)
{
        /* Set default values. */
        /* don't clear this flag.  oi->flag = OSPF_IF_DISABLE; */

        if (oi->vl_data)
                oi->type = OSPF_IFTYPE_VIRTUALLINK;
        else
                /* preserve network-type */
                if (oi->type != OSPF_IFTYPE_NBMA)
                oi->type = OSPF_IFTYPE_BROADCAST;

        oi->state = ISM_Down;

        oi->crypt_seqnum = 0;

        /* This must be short, (less than RxmtInterval)
           - RFC 2328 Section 13.5 para 3.  Set to 1 second to avoid Acks being
             held back for too long - MAG */
        oi->v_ls_ack = 1;
}

/* lookup oi for specified prefix/ifp */
struct ospf_interface *ospf_if_table_lookup(struct interface *ifp,
                                            struct prefix *prefix)
{
        struct prefix p;
        struct route_node *rn;
        struct ospf_interface *rninfo = NULL;

        p = *prefix;
        p.prefixlen = IPV4_MAX_BITLEN;

        /* route_node_get implicitely locks */
        if ((rn = route_node_lookup(IF_OIFS(ifp), &p))) {
                rninfo = (struct ospf_interface *)rn->info;
                route_unlock_node(rn);
        }

        return rninfo;
}

static void ospf_add_to_if(struct interface *ifp, struct ospf_interface *oi)
{
        struct route_node *rn;
        struct prefix p;

        p = *oi->address;
        p.prefixlen = IPV4_MAX_BITLEN;
        apply_mask(&p);

        rn = route_node_get(IF_OIFS(ifp), &p);
        /* rn->info should either be NULL or equal to this oi
         * as route_node_get may return an existing node
         */
        assert(!rn->info || rn->info == oi);
        rn->info = oi;
}

static void ospf_delete_from_if(struct interface *ifp,
                                struct ospf_interface *oi)
{
        struct route_node *rn;
        struct prefix p;

        p = *oi->address;
        p.prefixlen = IPV4_MAX_BITLEN;

        rn = route_node_lookup(IF_OIFS(oi->ifp), &p);
        assert(rn);
        assert(rn->info);
        rn->info = NULL;
        route_unlock_node(rn);
        route_unlock_node(rn);
}

struct ospf_interface *ospf_if_new(struct ospf *ospf, struct interface *ifp,
                                   struct prefix *p)
{
        struct ospf_interface *oi;

        oi = ospf_if_table_lookup(ifp, p);
        if (oi)
                return oi;

        oi = XCALLOC(MTYPE_OSPF_IF, sizeof(struct ospf_interface));

        oi->obuf = ospf_fifo_new();

        /* Set zebra interface pointer. */
        oi->ifp = ifp;
        oi->address = p;

        ospf_add_to_if(ifp, oi);
        listnode_add(ospf->oiflist, oi);

        /* Initialize neighbor list. */
        oi->nbrs = route_table_init();

        /* Initialize static neighbor list. */
        oi->nbr_nbma = list_new();

        /* Initialize Link State Acknowledgment list. */
        oi->ls_ack = list_new();
        oi->ls_ack_direct.ls_ack = list_new();

        /* Set default values. */
        ospf_if_reset_variables(oi);

        /* Set pseudo neighbor to Null */
        oi->nbr_self = NULL;

        oi->ls_upd_queue = route_table_init();
        oi->t_ls_upd_event = NULL;
        oi->t_ls_ack_direct = NULL;

        oi->crypt_seqnum = time(NULL);

        ospf_opaque_type9_lsa_init(oi);

        oi->ospf = ospf;

        QOBJ_REG(oi, ospf_interface);

        if (IS_DEBUG_OSPF_EVENT)
                zlog_debug("%s: ospf interface %s vrf %s id %u created",
                           __func__, ifp->name, ospf_get_name(ospf),
                           ospf->vrf_id);

        return oi;
}

/* Restore an interface to its pre UP state
   Used from ism_interface_down only */
void ospf_if_cleanup(struct ospf_interface *oi)
{
        struct route_node *rn;
        struct listnode *node, *nnode;
        struct ospf_neighbor *nbr;
        struct ospf_nbr_nbma *nbr_nbma;
        struct ospf_lsa *lsa;

        /* oi->nbrs and oi->nbr_nbma should be deleted on InterfaceDown event */
        /* delete all static neighbors attached to this interface */
        for (ALL_LIST_ELEMENTS(oi->nbr_nbma, node, nnode, nbr_nbma)) {
                THREAD_OFF(nbr_nbma->t_poll);

                if (nbr_nbma->nbr) {
                        nbr_nbma->nbr->nbr_nbma = NULL;
                        nbr_nbma->nbr = NULL;
                }

                nbr_nbma->oi = NULL;

                listnode_delete(oi->nbr_nbma, nbr_nbma);
        }

        /* send Neighbor event KillNbr to all associated neighbors. */
        for (rn = route_top(oi->nbrs); rn; rn = route_next(rn)) {
                if ((nbr = rn->info) != NULL)
                        if (nbr != oi->nbr_self)
                                OSPF_NSM_EVENT_EXECUTE(nbr, NSM_KillNbr);
        }

        /* Cleanup Link State Acknowlegdment list. */
        for (ALL_LIST_ELEMENTS(oi->ls_ack, node, nnode, lsa))
                ospf_lsa_unlock(&lsa); /* oi->ls_ack */
        list_delete_all_node(oi->ls_ack);

        oi->crypt_seqnum = 0;

        /* Empty link state update queue */
        ospf_ls_upd_queue_empty(oi);

        /* Reset pseudo neighbor. */
        ospf_nbr_self_reset(oi, oi->ospf->router_id);
}

void ospf_if_free(struct ospf_interface *oi)
{
        ospf_if_down(oi);

        ospf_fifo_free(oi->obuf);

        assert(oi->state == ISM_Down);

        ospf_opaque_type9_lsa_term(oi);

        QOBJ_UNREG(oi);

        /* Free Pseudo Neighbour */
        ospf_nbr_delete(oi->nbr_self);

        route_table_finish(oi->nbrs);
        route_table_finish(oi->ls_upd_queue);

        /* Free any lists that should be freed */
        list_delete(&oi->nbr_nbma);

        list_delete(&oi->ls_ack);
        list_delete(&oi->ls_ack_direct.ls_ack);

        if (IS_DEBUG_OSPF_EVENT)
                zlog_debug("%s: ospf interface %s vrf %s id %u deleted",
                           __func__, oi->ifp->name, oi->ifp->vrf->name,
                           oi->ifp->vrf->vrf_id);

        ospf_delete_from_if(oi->ifp, oi);

        listnode_delete(oi->ospf->oiflist, oi);
        listnode_delete(oi->area->oiflist, oi);

        thread_cancel_event(master, oi);

        memset(oi, 0, sizeof(*oi));
        XFREE(MTYPE_OSPF_IF, oi);
}

int ospf_if_is_up(struct ospf_interface *oi)
{
        return if_is_up(oi->ifp);
}

struct ospf_interface *ospf_if_exists(struct ospf_interface *oic)
{
        struct listnode *node;
        struct ospf *ospf;
        struct ospf_interface *oi;

        if (!oic)
                return NULL;

        ospf = oic->ospf;
        if (ospf == NULL)
                return NULL;

        for (ALL_LIST_ELEMENTS_RO(ospf->oiflist, node, oi))
                if (oi == oic)
                        return oi;

        return NULL;
}

/* Lookup OSPF interface by router LSA posistion */
struct ospf_interface *ospf_if_lookup_by_lsa_pos(struct ospf_area *area,
                                                 int lsa_pos)
{
        struct listnode *node;
        struct ospf_interface *oi;

        for (ALL_LIST_ELEMENTS_RO(area->oiflist, node, oi)) {
                if (lsa_pos >= oi->lsa_pos_beg && lsa_pos < oi->lsa_pos_end)
                        return oi;
        }
        return NULL;
}

struct ospf_interface *ospf_if_lookup_by_local_addr(struct ospf *ospf,
                                                    struct interface *ifp,
                                                    struct in_addr address)
{
        struct listnode *node;
        struct ospf_interface *oi;

        for (ALL_LIST_ELEMENTS_RO(ospf->oiflist, node, oi))
                if (oi->type != OSPF_IFTYPE_VIRTUALLINK) {
                        if (ifp && oi->ifp != ifp)
                                continue;

                        if (IPV4_ADDR_SAME(&address, &oi->address->u.prefix4))
                                return oi;
                }

        return NULL;
}

struct ospf_interface *ospf_if_lookup_by_prefix(struct ospf *ospf,
                                                struct prefix_ipv4 *p)
{
        struct listnode *node;
        struct ospf_interface *oi;

        /* Check each Interface. */
        for (ALL_LIST_ELEMENTS_RO(ospf->oiflist, node, oi)) {
                if (oi->type != OSPF_IFTYPE_VIRTUALLINK) {
                        struct prefix ptmp;

                        prefix_copy(&ptmp, CONNECTED_PREFIX(oi->connected));
                        apply_mask(&ptmp);
                        if (prefix_same(&ptmp, (struct prefix *)p))
                                return oi;
                }
        }
        return NULL;
}

/* determine receiving interface by ifp and source address */
struct ospf_interface *ospf_if_lookup_recv_if(struct ospf *ospf,
                                              struct in_addr src,
                                              struct interface *ifp)
{
        struct route_node *rn;
        struct prefix_ipv4 addr;
        struct ospf_interface *oi, *match;

        addr.family = AF_INET;
        addr.prefix = src;
        addr.prefixlen = IPV4_MAX_BITLEN;

        match = NULL;

        for (rn = route_top(IF_OIFS(ifp)); rn; rn = route_next(rn)) {
                oi = rn->info;

                if (!oi) /* oi can be NULL for PtP aliases */
                        continue;

                if (oi->type == OSPF_IFTYPE_VIRTUALLINK)
                        continue;

                if (if_is_loopback(oi->ifp))
                        continue;

                if (CHECK_FLAG(oi->connected->flags, ZEBRA_IFA_UNNUMBERED))
                        match = oi;
                else if (prefix_match(CONNECTED_PREFIX(oi->connected),
                                      (struct prefix *)&addr)) {
                        if ((match == NULL) || (match->address->prefixlen
                                                < oi->address->prefixlen))
                                match = oi;
                }
        }

        return match;
}

void ospf_interface_fifo_flush(struct ospf_interface *oi)
{
        struct ospf *ospf = oi->ospf;

        ospf_fifo_flush(oi->obuf);

        if (oi->on_write_q) {
                listnode_delete(ospf->oi_write_q, oi);
                if (list_isempty(ospf->oi_write_q))
                        THREAD_OFF(ospf->t_write);
                oi->on_write_q = 0;
        }
}

static void ospf_if_reset_stats(struct ospf_interface *oi)
{
        oi->hello_in = oi->hello_out = 0;
        oi->db_desc_in = oi->db_desc_out = 0;
        oi->ls_req_in = oi->ls_req_out = 0;
        oi->ls_upd_in = oi->ls_upd_out = 0;
        oi->ls_ack_in = oi->ls_ack_out = 0;
}

void ospf_if_stream_unset(struct ospf_interface *oi)
{
        /* flush the interface packet queue */
        ospf_interface_fifo_flush(oi);
        /*reset protocol stats */
        ospf_if_reset_stats(oi);
}


static struct ospf_if_params *ospf_new_if_params(void)
{
        struct ospf_if_params *oip;

        oip = XCALLOC(MTYPE_OSPF_IF_PARAMS, sizeof(struct ospf_if_params));

        UNSET_IF_PARAM(oip, output_cost_cmd);
        UNSET_IF_PARAM(oip, transmit_delay);
        UNSET_IF_PARAM(oip, retransmit_interval);
        UNSET_IF_PARAM(oip, passive_interface);
        UNSET_IF_PARAM(oip, v_hello);
        UNSET_IF_PARAM(oip, fast_hello);
        UNSET_IF_PARAM(oip, v_wait);
        UNSET_IF_PARAM(oip, priority);
        UNSET_IF_PARAM(oip, type);
        UNSET_IF_PARAM(oip, auth_simple);
        UNSET_IF_PARAM(oip, auth_crypt);
        UNSET_IF_PARAM(oip, auth_type);
        UNSET_IF_PARAM(oip, if_area);

        oip->auth_crypt = list_new();

        oip->network_lsa_seqnum = htonl(OSPF_INITIAL_SEQUENCE_NUMBER);
        oip->is_v_wait_set = false;

        oip->ptp_dmvpn = 0;

        return oip;
}

static void ospf_del_if_params(struct interface *ifp,
                               struct ospf_if_params *oip)
{
        list_delete(&oip->auth_crypt);
        ospf_interface_disable_bfd(ifp, oip);
        ldp_sync_info_free(&(oip->ldp_sync_info));
        XFREE(MTYPE_OSPF_IF_PARAMS, oip);
}

void ospf_free_if_params(struct interface *ifp, struct in_addr addr)
{
        struct ospf_if_params *oip;
        struct prefix_ipv4 p;
        struct route_node *rn;

        p.family = AF_INET;
        p.prefixlen = IPV4_MAX_BITLEN;
        p.prefix = addr;
        rn = route_node_lookup(IF_OIFS_PARAMS(ifp), (struct prefix *)&p);
        if (!rn || !rn->info)
                return;

        oip = rn->info;
        route_unlock_node(rn);

        if (!OSPF_IF_PARAM_CONFIGURED(oip, output_cost_cmd)
            && !OSPF_IF_PARAM_CONFIGURED(oip, transmit_delay)
            && !OSPF_IF_PARAM_CONFIGURED(oip, retransmit_interval)
            && !OSPF_IF_PARAM_CONFIGURED(oip, passive_interface)
            && !OSPF_IF_PARAM_CONFIGURED(oip, v_hello)
            && !OSPF_IF_PARAM_CONFIGURED(oip, fast_hello)
            && !OSPF_IF_PARAM_CONFIGURED(oip, v_wait)
            && !OSPF_IF_PARAM_CONFIGURED(oip, priority)
            && !OSPF_IF_PARAM_CONFIGURED(oip, type)
            && !OSPF_IF_PARAM_CONFIGURED(oip, auth_simple)
            && !OSPF_IF_PARAM_CONFIGURED(oip, auth_type)
            && !OSPF_IF_PARAM_CONFIGURED(oip, if_area)
            && listcount(oip->auth_crypt) == 0) {
                ospf_del_if_params(ifp, oip);
                rn->info = NULL;
                route_unlock_node(rn);
        }
}

struct ospf_if_params *ospf_lookup_if_params(struct interface *ifp,
                                             struct in_addr addr)
{
        struct prefix_ipv4 p;
        struct route_node *rn;

        p.family = AF_INET;
        p.prefixlen = IPV4_MAX_BITLEN;
        p.prefix = addr;

        rn = route_node_lookup(IF_OIFS_PARAMS(ifp), (struct prefix *)&p);

        if (rn) {
                route_unlock_node(rn);
                return rn->info;
        }

        return NULL;
}

struct ospf_if_params *ospf_get_if_params(struct interface *ifp,
                                          struct in_addr addr)
{
        struct prefix_ipv4 p;
        struct route_node *rn;

        p.family = AF_INET;
        p.prefixlen = IPV4_MAX_BITLEN;
        p.prefix = addr;
        apply_mask_ipv4(&p);

        rn = route_node_get(IF_OIFS_PARAMS(ifp), (struct prefix *)&p);

        if (rn->info == NULL)
                rn->info = ospf_new_if_params();
        else
                route_unlock_node(rn);

        return rn->info;
}

void ospf_if_update_params(struct interface *ifp, struct in_addr addr)
{
        struct route_node *rn;
        struct ospf_interface *oi;

        for (rn = route_top(IF_OIFS(ifp)); rn; rn = route_next(rn)) {
                if ((oi = rn->info) == NULL)
                        continue;

                if (IPV4_ADDR_SAME(&oi->address->u.prefix4, &addr))
                        oi->params = ospf_lookup_if_params(
                                ifp, oi->address->u.prefix4);
        }
}

int ospf_if_new_hook(struct interface *ifp)
{
        int rc = 0;

        ifp->info = XCALLOC(MTYPE_OSPF_IF_INFO, sizeof(struct ospf_if_info));

        IF_OIFS(ifp) = route_table_init();
        IF_OIFS_PARAMS(ifp) = route_table_init();

        IF_DEF_PARAMS(ifp) = ospf_new_if_params();

        SET_IF_PARAM(IF_DEF_PARAMS(ifp), transmit_delay);
        IF_DEF_PARAMS(ifp)->transmit_delay = OSPF_TRANSMIT_DELAY_DEFAULT;

        SET_IF_PARAM(IF_DEF_PARAMS(ifp), retransmit_interval);
        IF_DEF_PARAMS(ifp)->retransmit_interval =
                OSPF_RETRANSMIT_INTERVAL_DEFAULT;

        SET_IF_PARAM(IF_DEF_PARAMS(ifp), priority);
        IF_DEF_PARAMS(ifp)->priority = OSPF_ROUTER_PRIORITY_DEFAULT;

        IF_DEF_PARAMS(ifp)->mtu_ignore = OSPF_MTU_IGNORE_DEFAULT;

        SET_IF_PARAM(IF_DEF_PARAMS(ifp), v_hello);
        IF_DEF_PARAMS(ifp)->v_hello = OSPF_HELLO_INTERVAL_DEFAULT;

        SET_IF_PARAM(IF_DEF_PARAMS(ifp), fast_hello);
        IF_DEF_PARAMS(ifp)->fast_hello = OSPF_FAST_HELLO_DEFAULT;

        SET_IF_PARAM(IF_DEF_PARAMS(ifp), v_wait);
        IF_DEF_PARAMS(ifp)->v_wait = OSPF_ROUTER_DEAD_INTERVAL_DEFAULT;

        SET_IF_PARAM(IF_DEF_PARAMS(ifp), auth_simple);
        memset(IF_DEF_PARAMS(ifp)->auth_simple, 0, OSPF_AUTH_SIMPLE_SIZE);

        SET_IF_PARAM(IF_DEF_PARAMS(ifp), auth_type);
        IF_DEF_PARAMS(ifp)->auth_type = OSPF_AUTH_NOTSET;

        rc = ospf_opaque_new_if(ifp);
        return rc;
}

static int ospf_if_delete_hook(struct interface *ifp)
{
        int rc = 0;
        struct route_node *rn;
        rc = ospf_opaque_del_if(ifp);

        /*
         * This function must be called before `route_table_finish` due to
         * BFD integration need to iterate over the interface neighbors to
         * remove all registrations.
         */
        ospf_del_if_params(ifp, IF_DEF_PARAMS(ifp));

        for (rn = route_top(IF_OIFS_PARAMS(ifp)); rn; rn = route_next(rn))
                if (rn->info)
                        ospf_del_if_params(ifp, rn->info);

        route_table_finish(IF_OIFS(ifp));
        route_table_finish(IF_OIFS_PARAMS(ifp));

        XFREE(MTYPE_OSPF_IF_INFO, ifp->info);

        return rc;
}

int ospf_if_is_enable(struct ospf_interface *oi)
{
        if (!(if_is_loopback(oi->ifp)))
                if (if_is_up(oi->ifp))
                        return 1;

        return 0;
}

void ospf_if_set_multicast(struct ospf_interface *oi)
{
        if ((oi->state > ISM_Loopback) && (oi->type != OSPF_IFTYPE_LOOPBACK)
            && (oi->type != OSPF_IFTYPE_VIRTUALLINK)
            && (OSPF_IF_PASSIVE_STATUS(oi) == OSPF_IF_ACTIVE)) {
                /* The interface should belong to the OSPF-all-routers group. */
                if (!OI_MEMBER_CHECK(oi, MEMBER_ALLROUTERS)
                    && (ospf_if_add_allspfrouters(oi->ospf, oi->address,
                                                  oi->ifp->ifindex)
                        >= 0))
                        /* Set the flag only if the system call to join
                         * succeeded. */
                        OI_MEMBER_JOINED(oi, MEMBER_ALLROUTERS);
        } else {
                /* The interface should NOT belong to the OSPF-all-routers
                 * group. */
                if (OI_MEMBER_CHECK(oi, MEMBER_ALLROUTERS)) {
                        /* Only actually drop if this is the last reference */
                        if (OI_MEMBER_COUNT(oi, MEMBER_ALLROUTERS) == 1)
                                ospf_if_drop_allspfrouters(oi->ospf,
                                                           oi->address,
                                                           oi->ifp->ifindex);
                        /* Unset the flag regardless of whether the system call
                           to leave
                           the group succeeded, since it's much safer to assume
                           that
                           we are not a member. */
                        OI_MEMBER_LEFT(oi, MEMBER_ALLROUTERS);
                }
        }

        if (((oi->type == OSPF_IFTYPE_BROADCAST)
             || (oi->type == OSPF_IFTYPE_POINTOPOINT))
            && ((oi->state == ISM_DR) || (oi->state == ISM_Backup))
            && (OSPF_IF_PASSIVE_STATUS(oi) == OSPF_IF_ACTIVE)) {
                /* The interface should belong to the OSPF-designated-routers
                 * group. */
                if (!OI_MEMBER_CHECK(oi, MEMBER_DROUTERS)
                    && (ospf_if_add_alldrouters(oi->ospf, oi->address,
                                                oi->ifp->ifindex)
                        >= 0))
                        /* Set the flag only if the system call to join
                         * succeeded. */
                        OI_MEMBER_JOINED(oi, MEMBER_DROUTERS);
        } else {
                /* The interface should NOT belong to the
                 * OSPF-designated-routers group */
                if (OI_MEMBER_CHECK(oi, MEMBER_DROUTERS)) {
                        /* drop only if last reference */
                        if (OI_MEMBER_COUNT(oi, MEMBER_DROUTERS) == 1)
                                ospf_if_drop_alldrouters(oi->ospf, oi->address,
                                                         oi->ifp->ifindex);

                        /* Unset the flag regardless of whether the system call
                           to leave
                           the group succeeded, since it's much safer to assume
                           that
                           we are not a member. */
                        OI_MEMBER_LEFT(oi, MEMBER_DROUTERS);
                }
        }
}

int ospf_if_up(struct ospf_interface *oi)
{
        if (oi == NULL)
                return 0;

        if (oi->type == OSPF_IFTYPE_LOOPBACK)
                OSPF_ISM_EVENT_SCHEDULE(oi, ISM_LoopInd);
        else {
                OSPF_ISM_EVENT_SCHEDULE(oi, ISM_InterfaceUp);
        }

        return 1;
}

int ospf_if_down(struct ospf_interface *oi)
{
        struct ospf *ospf;
        struct route_node *rn;
        struct ospf_route *or;
        struct listnode *nh;
        struct ospf_path *op;

        if (oi == NULL)
                return 0;

        ospf = oi->ospf;

        /* Cease the HELPER role for all the neighbours
         * of this interface.
         */
        if (ospf->is_helper_supported) {
                struct route_node *rn = NULL;

                if (ospf_interface_neighbor_count(oi)) {
                        for (rn = route_top(oi->nbrs); rn;
                             rn = route_next(rn)) {
                                struct ospf_neighbor *nbr = NULL;

                                if (!rn->info)
                                        continue;

                                nbr = rn->info;

                                if (OSPF_GR_IS_ACTIVE_HELPER(nbr))
                                        ospf_gr_helper_exit(
                                                nbr, OSPF_GR_HELPER_TOPO_CHG);
                        }
                }
        }

        OSPF_ISM_EVENT_EXECUTE(oi, ISM_InterfaceDown);
        /* delete position in router LSA */
        oi->lsa_pos_beg = 0;
        oi->lsa_pos_end = 0;
        /* Shutdown packet reception and sending */
        ospf_if_stream_unset(oi);

        if (!ospf->new_table)
                return 1;
        for (rn = route_top(ospf->new_table); rn; rn = route_next(rn)) {
                or = rn->info;

                if (!or)
                        continue;

                for (nh = listhead(or->paths); nh;
                     nh = listnextnode_unchecked(nh)) {
                        op = listgetdata(nh);
                        if (op->ifindex == oi->ifp->ifindex) {
                                or->changed = true;
                                break;
                        }
                }
        }

        return 1;
}


/* Virtual Link related functions. */

struct ospf_vl_data *ospf_vl_data_new(struct ospf_area *area,
                                      struct in_addr vl_peer)
{
        struct ospf_vl_data *vl_data;

        vl_data = XCALLOC(MTYPE_OSPF_VL_DATA, sizeof(struct ospf_vl_data));

        vl_data->vl_peer.s_addr = vl_peer.s_addr;
        vl_data->vl_area_id = area->area_id;
        vl_data->vl_area_id_fmt = area->area_id_fmt;

        return vl_data;
}

void ospf_vl_data_free(struct ospf_vl_data *vl_data)
{
        XFREE(MTYPE_OSPF_VL_DATA, vl_data);
}

unsigned int vlink_count = 0;

struct ospf_interface *ospf_vl_new(struct ospf *ospf,
                                   struct ospf_vl_data *vl_data)
{
        struct ospf_interface *voi;
        struct interface *vi;
        char ifname[INTERFACE_NAMSIZ];
        struct ospf_area *area;
        struct in_addr area_id;
        struct connected *co;
        struct prefix_ipv4 *p;

        if (IS_DEBUG_OSPF_EVENT)
                zlog_debug("%s: (%s): Start", __func__, ospf_get_name(ospf));
        if (vlink_count == OSPF_VL_MAX_COUNT) {
                if (IS_DEBUG_OSPF_EVENT)
                        zlog_debug(
                                "%s: Alarm: cannot create more than OSPF_MAX_VL_COUNT virtual links",
                                __func__);

                return NULL;
        }

        if (IS_DEBUG_OSPF_EVENT)
                zlog_debug("%s: creating pseudo zebra interface vrf id %u",
                           __func__, ospf->vrf_id);

        snprintf(ifname, sizeof(ifname), "VLINK%u", vlink_count);
        vi = if_get_by_name(ifname, ospf->vrf_id, ospf->name);
        /*
         * if_get_by_name sets ZEBRA_INTERFACE_LINKDETECTION
         * virtual links don't need this.
         */
        UNSET_FLAG(vi->status, ZEBRA_INTERFACE_LINKDETECTION);
        co = connected_new();
        co->ifp = vi;
        listnode_add(vi->connected, co);

        p = prefix_ipv4_new();
        p->family = AF_INET;
        p->prefix.s_addr = INADDR_ANY;
        p->prefixlen = 0;

        co->address = (struct prefix *)p;

        voi = ospf_if_new(ospf, vi, co->address);
        if (voi == NULL) {
                if (IS_DEBUG_OSPF_EVENT)
                        zlog_debug(
                                "%s: Alarm: OSPF int structure is not created",
                                __func__);

                return NULL;
        }
        voi->connected = co;
        voi->vl_data = vl_data;
        voi->ifp->mtu = OSPF_VL_MTU;
        voi->type = OSPF_IFTYPE_VIRTUALLINK;

        vlink_count++;
        if (IS_DEBUG_OSPF_EVENT)
                zlog_debug("%s: Created name: %s set if->name to %s", __func__,
                           ifname, vi->name);

        area_id.s_addr = INADDR_ANY;
        area = ospf_area_get(ospf, area_id);
        voi->area = area;

        if (IS_DEBUG_OSPF_EVENT)
                zlog_debug("%s: set associated area to the backbone", __func__);

        /* Add pseudo neighbor. */
        ospf_nbr_self_reset(voi, voi->ospf->router_id);

        ospf_area_add_if(voi->area, voi);

        if (IS_DEBUG_OSPF_EVENT)
                zlog_debug("%s: Stop", __func__);
        return voi;
}

static void ospf_vl_if_delete(struct ospf_vl_data *vl_data)
{
        struct interface *ifp = vl_data->vl_oi->ifp;
        struct vrf *vrf = ifp->vrf;

        vl_data->vl_oi->address->u.prefix4.s_addr = INADDR_ANY;
        vl_data->vl_oi->address->prefixlen = 0;
        ospf_if_free(vl_data->vl_oi);
        if_delete(&ifp);
        if (!vrf_is_enabled(vrf))
                vrf_delete(vrf);
        vlink_count--;
}

/* for a defined area, count the number of configured vl
 */
int ospf_vl_count(struct ospf *ospf, struct ospf_area *area)
{
        int count = 0;
        struct ospf_vl_data *vl_data;
        struct listnode *node;

        for (ALL_LIST_ELEMENTS_RO(ospf->vlinks, node, vl_data)) {
                if (area
                    && !IPV4_ADDR_SAME(&vl_data->vl_area_id, &area->area_id))
                        continue;
                count++;
        }
        return count;
}

/* Look up vl_data for given peer, optionally qualified to be in the
 * specified area. NULL area returns first found..
 */
struct ospf_vl_data *ospf_vl_lookup(struct ospf *ospf, struct ospf_area *area,
                                    struct in_addr vl_peer)
{
        struct ospf_vl_data *vl_data;
        struct listnode *node;

        if (IS_DEBUG_OSPF_EVENT) {
                zlog_debug("%s: Looking for %pI4", __func__, &vl_peer);
                if (area)
                        zlog_debug("%s: in area %pI4", __func__,
                                   &area->area_id);
        }

        for (ALL_LIST_ELEMENTS_RO(ospf->vlinks, node, vl_data)) {
                if (IS_DEBUG_OSPF_EVENT)
                        zlog_debug("%s: VL %s, peer %pI4", __func__,
                                   vl_data->vl_oi->ifp->name,
                                   &vl_data->vl_peer);

                if (area
                    && !IPV4_ADDR_SAME(&vl_data->vl_area_id, &area->area_id))
                        continue;

                if (IPV4_ADDR_SAME(&vl_data->vl_peer, &vl_peer))
                        return vl_data;
        }

        return NULL;
}

static void ospf_vl_shutdown(struct ospf_vl_data *vl_data)
{
        struct ospf_interface *oi;

        if ((oi = vl_data->vl_oi) == NULL)
                return;

        oi->address->u.prefix4.s_addr = INADDR_ANY;
        oi->address->prefixlen = 0;

        UNSET_FLAG(oi->ifp->flags, IFF_UP);
        /* OSPF_ISM_EVENT_SCHEDULE (oi, ISM_InterfaceDown); */
        OSPF_ISM_EVENT_EXECUTE(oi, ISM_InterfaceDown);
}

void ospf_vl_add(struct ospf *ospf, struct ospf_vl_data *vl_data)
{
        listnode_add(ospf->vlinks, vl_data);
        hook_call(ospf_vl_add, vl_data);
}

void ospf_vl_delete(struct ospf *ospf, struct ospf_vl_data *vl_data)
{
        ospf_vl_shutdown(vl_data);
        ospf_vl_if_delete(vl_data);

        hook_call(ospf_vl_delete, vl_data);
        listnode_delete(ospf->vlinks, vl_data);

        ospf_vl_data_free(vl_data);
}

static int ospf_vl_set_params(struct ospf_area *area,
                              struct ospf_vl_data *vl_data, struct vertex *v)
{
        int changed = 0;
        struct ospf_interface *voi;
        struct listnode *node;
        struct vertex_parent *vp = NULL;
        unsigned int i;
        struct router_lsa *rl;
        struct ospf_interface *oi;

        voi = vl_data->vl_oi;

        if (voi->output_cost != v->distance) {

                voi->output_cost = v->distance;
                changed = 1;
        }

        for (ALL_LIST_ELEMENTS_RO(v->parents, node, vp)) {
                vl_data->nexthop.lsa_pos = vp->nexthop->lsa_pos;
                vl_data->nexthop.router = vp->nexthop->router;

                /*
                 * Only deal with interface data when the local
                 * (calculating) node is the SPF root node
                 */
                if (!area->spf_dry_run) {
                        oi = ospf_if_lookup_by_lsa_pos(
                                area, vl_data->nexthop.lsa_pos);

                        if (!IPV4_ADDR_SAME(&voi->address->u.prefix4,
                                            &oi->address->u.prefix4))
                                changed = 1;

                        voi->address->u.prefix4 = oi->address->u.prefix4;
                        voi->address->prefixlen = oi->address->prefixlen;
                }

                break; /* We take the first interface. */
        }

        rl = (struct router_lsa *)v->lsa;

        /* use SPF determined backlink index in struct vertex
         * for virtual link destination address
         */
        if (vp && vp->backlink >= 0) {
                if (!IPV4_ADDR_SAME(&vl_data->peer_addr,
                                    &rl->link[vp->backlink].link_data))
                        changed = 1;
                vl_data->peer_addr = rl->link[vp->backlink].link_data;
        } else {
                /* This is highly odd, there is no backlink index
                 * there should be due to the ospf_spf_has_link() check
                 * in SPF. Lets warn and try pick a link anyway.
                 */
                zlog_info("ospf_vl_set_params: No backlink for %s!",
                          vl_data->vl_oi->ifp->name);
                for (i = 0; i < ntohs(rl->links); i++) {
                        switch (rl->link[i].type) {
                        case LSA_LINK_TYPE_VIRTUALLINK:
                                if (IS_DEBUG_OSPF_EVENT)
                                        zlog_debug(
                                                "found back link through VL");
                        /* fallthru */
                        case LSA_LINK_TYPE_TRANSIT:
                        case LSA_LINK_TYPE_POINTOPOINT:
                                if (!IPV4_ADDR_SAME(&vl_data->peer_addr,
                                                    &rl->link[i].link_data))
                                        changed = 1;
                                vl_data->peer_addr = rl->link[i].link_data;
                        }
                }
        }

        if (IS_DEBUG_OSPF_EVENT)
                zlog_debug("%s: %s peer address: %pI4, cost: %d,%schanged",
                           __func__, vl_data->vl_oi->ifp->name,
                           &vl_data->peer_addr, voi->output_cost,
                           (changed ? " " : " un"));

        return changed;
}


void ospf_vl_up_check(struct ospf_area *area, struct in_addr rid,
                      struct vertex *v)
{
        struct ospf *ospf = area->ospf;
        struct listnode *node;
        struct ospf_vl_data *vl_data;
        struct ospf_interface *oi;

        if (IS_DEBUG_OSPF_EVENT) {
                zlog_debug("%s: Start", __func__);
                zlog_debug("%s: Router ID is %pI4 Area is %pI4", __func__, &rid,
                           &area->area_id);
        }

        for (ALL_LIST_ELEMENTS_RO(ospf->vlinks, node, vl_data)) {
                if (IS_DEBUG_OSPF_EVENT) {
                        zlog_debug("%s: considering VL, %s in area %pI4",
                                   __func__, vl_data->vl_oi->ifp->name,
                                   &vl_data->vl_area_id);
                        zlog_debug("%s: peer ID: %pI4", __func__,
                                   &vl_data->vl_peer);
                }

                if (IPV4_ADDR_SAME(&vl_data->vl_peer, &rid)
                    && IPV4_ADDR_SAME(&vl_data->vl_area_id, &area->area_id)) {
                        oi = vl_data->vl_oi;
                        SET_FLAG(vl_data->flags, OSPF_VL_FLAG_APPROVED);

                        if (IS_DEBUG_OSPF_EVENT)
                                zlog_debug("%s: this VL matched", __func__);

                        if (oi->state == ISM_Down) {
                                if (IS_DEBUG_OSPF_EVENT)
                                        zlog_debug(
                                                "%s: VL is down, waking it up",
                                                __func__);
                                SET_FLAG(oi->ifp->flags, IFF_UP);
                                OSPF_ISM_EVENT_EXECUTE(oi, ISM_InterfaceUp);
                        }

                        if (ospf_vl_set_params(area, vl_data, v)) {
                                if (IS_DEBUG_OSPF(ism, ISM_EVENTS))
                                        zlog_debug(
                                                "%s: VL cost change, scheduling router lsa refresh",
                                                __func__);
                                if (ospf->backbone)
                                        ospf_router_lsa_update_area(
                                                ospf->backbone);
                                else if (IS_DEBUG_OSPF(ism, ISM_EVENTS))
                                        zlog_debug(
                                                "%s: VL cost change, no backbone!",
                                                __func__);
                        }
                }
        }
}

void ospf_vl_unapprove(struct ospf *ospf)
{
        struct listnode *node;
        struct ospf_vl_data *vl_data;

        for (ALL_LIST_ELEMENTS_RO(ospf->vlinks, node, vl_data))
                UNSET_FLAG(vl_data->flags, OSPF_VL_FLAG_APPROVED);
}

void ospf_vl_shut_unapproved(struct ospf *ospf)
{
        struct listnode *node, *nnode;
        struct ospf_vl_data *vl_data;

        for (ALL_LIST_ELEMENTS(ospf->vlinks, node, nnode, vl_data))
                if (!CHECK_FLAG(vl_data->flags, OSPF_VL_FLAG_APPROVED))
                        ospf_vl_shutdown(vl_data);
}

int ospf_full_virtual_nbrs(struct ospf_area *area)
{
        if (IS_DEBUG_OSPF_EVENT) {
                zlog_debug(
                        "counting fully adjacent virtual neighbors in area %pI4",
                        &area->area_id);
                zlog_debug("there are %d of them", area->full_vls);
        }

        return area->full_vls;
}

int ospf_vls_in_area(struct ospf_area *area)
{
        struct listnode *node;
        struct ospf_vl_data *vl_data;
        int c = 0;

        for (ALL_LIST_ELEMENTS_RO(area->ospf->vlinks, node, vl_data))
                if (IPV4_ADDR_SAME(&vl_data->vl_area_id, &area->area_id))
                        c++;

        return c;
}


struct crypt_key *ospf_crypt_key_new(void)
{
        return XCALLOC(MTYPE_OSPF_CRYPT_KEY, sizeof(struct crypt_key));
}

void ospf_crypt_key_add(struct list *crypt, struct crypt_key *ck)
{
        listnode_add(crypt, ck);
}

struct crypt_key *ospf_crypt_key_lookup(struct list *auth_crypt, uint8_t key_id)
{
        struct listnode *node;
        struct crypt_key *ck;

        for (ALL_LIST_ELEMENTS_RO(auth_crypt, node, ck))
                if (ck->key_id == key_id)
                        return ck;

        return NULL;
}

int ospf_crypt_key_delete(struct list *auth_crypt, uint8_t key_id)
{
        struct listnode *node, *nnode;
        struct crypt_key *ck;

        for (ALL_LIST_ELEMENTS(auth_crypt, node, nnode, ck)) {
                if (ck->key_id == key_id) {
                        listnode_delete(auth_crypt, ck);
                        XFREE(MTYPE_OSPF_CRYPT_KEY, ck);
                        return 1;
                }
        }

        return 0;
}

uint8_t ospf_default_iftype(struct interface *ifp)
{
        if (if_is_pointopoint(ifp))
                return OSPF_IFTYPE_POINTOPOINT;
        else if (if_is_loopback(ifp))
                return OSPF_IFTYPE_LOOPBACK;
        else
                return OSPF_IFTYPE_BROADCAST;
}

void ospf_if_interface(struct interface *ifp)
{
        hook_call(ospf_if_update, ifp);
}

uint32_t ospf_if_count_area_params(struct interface *ifp)
{
        struct ospf_if_params *params;
        struct route_node *rn;
        uint32_t count = 0;

        params = IF_DEF_PARAMS(ifp);
        if (OSPF_IF_PARAM_CONFIGURED(params, if_area))
                count++;

        for (rn = route_top(IF_OIFS_PARAMS(ifp)); rn; rn = route_next(rn))
                if ((params = rn->info)
                    && OSPF_IF_PARAM_CONFIGURED(params, if_area))
                        count++;

        return count;
}

static int ospf_ifp_create(struct interface *ifp)
{
        struct ospf *ospf = NULL;
        struct ospf_if_info *oii;

        if (IS_DEBUG_OSPF(zebra, ZEBRA_INTERFACE))
                zlog_debug(
                        "Zebra: interface add %s vrf %s[%u] index %d flags %llx metric %d mtu %d speed %u",
                        ifp->name, ifp->vrf->name, ifp->vrf->vrf_id,
                        ifp->ifindex, (unsigned long long)ifp->flags,
                        ifp->metric, ifp->mtu, ifp->speed);

        assert(ifp->info);

        oii = ifp->info;
        oii->curr_mtu = ifp->mtu;

        if (IF_DEF_PARAMS(ifp)
            && !OSPF_IF_PARAM_CONFIGURED(IF_DEF_PARAMS(ifp), type)) {
                SET_IF_PARAM(IF_DEF_PARAMS(ifp), type);
                IF_DEF_PARAMS(ifp)->type = ospf_default_iftype(ifp);
        }

        ospf = ifp->vrf->info;
        if (!ospf)
                return 0;

        if (ospf_if_count_area_params(ifp) > 0)
                ospf_interface_area_set(ospf, ifp);

        ospf_if_recalculate_output_cost(ifp);

        ospf_if_update(ospf, ifp);

        if (HAS_LINK_PARAMS(ifp))
                ospf_mpls_te_update_if(ifp);

        hook_call(ospf_if_update, ifp);

        return 0;
}

static int ospf_ifp_up(struct interface *ifp)
{
        struct ospf_interface *oi;
        struct route_node *rn;
        struct ospf_if_info *oii = ifp->info;

        ospf_if_recalculate_output_cost(ifp);

        if (oii && oii->curr_mtu != ifp->mtu) {
                if (IS_DEBUG_OSPF(zebra, ZEBRA_INTERFACE))
                        zlog_debug(
                                "Zebra: Interface[%s] MTU change %u -> %u.",
                                ifp->name, oii->curr_mtu, ifp->mtu);

                oii->curr_mtu = ifp->mtu;
                /* Must reset the interface (simulate down/up) when MTU
                 * changes. */
                ospf_if_reset(ifp);

                return 0;
        }

        if (IS_DEBUG_OSPF(zebra, ZEBRA_INTERFACE))
                zlog_debug("Zebra: Interface[%s] state change to up.",
                           ifp->name);

        for (rn = route_top(IF_OIFS(ifp)); rn; rn = route_next(rn)) {
                if ((oi = rn->info) == NULL)
                        continue;

                ospf_if_up(oi);
        }

        if (HAS_LINK_PARAMS(ifp))
                ospf_mpls_te_update_if(ifp);

        return 0;
}

static int ospf_ifp_down(struct interface *ifp)
{
        struct ospf_interface *oi;
        struct route_node *node;

        if (IS_DEBUG_OSPF(zebra, ZEBRA_INTERFACE))
                zlog_debug("Zebra: Interface[%s] state change to down.",
                           ifp->name);

        for (node = route_top(IF_OIFS(ifp)); node; node = route_next(node)) {
                if ((oi = node->info) == NULL)
                        continue;
                ospf_if_down(oi);
        }

        return 0;
}

static int ospf_ifp_destroy(struct interface *ifp)
{
        struct ospf *ospf;
        struct route_node *rn;

        if (IS_DEBUG_OSPF(zebra, ZEBRA_INTERFACE))
                zlog_debug(
                        "Zebra: interface delete %s vrf %s[%u] index %d flags %llx metric %d mtu %d",
                        ifp->name, ifp->vrf->name, ifp->vrf->vrf_id,
                        ifp->ifindex, (unsigned long long)ifp->flags,
                        ifp->metric, ifp->mtu);

        hook_call(ospf_if_delete, ifp);

        ospf = ifp->vrf->info;
        if (ospf) {
                if (ospf_if_count_area_params(ifp) > 0)
                        ospf_interface_area_unset(ospf, ifp);
        }

        for (rn = route_top(IF_OIFS(ifp)); rn; rn = route_next(rn))
                if (rn->info)
                        ospf_if_free((struct ospf_interface *)rn->info);

        return 0;
}

/* Resetting ospf hello timer */
void ospf_reset_hello_timer(struct interface *ifp, struct in_addr addr,
                            bool is_addr)
{
        struct route_node *rn;

        if (is_addr) {
                struct prefix p;
                struct ospf_interface *oi = NULL;

                p.u.prefix4 = addr;
                p.family = AF_INET;
                p.prefixlen = IPV4_MAX_BITLEN;

                oi = ospf_if_table_lookup(ifp, &p);

                if (oi) {
                        /* Send hello before restart the hello timer
                         * to avoid session flaps in case of bigger
                         * hello interval configurations.
                         */
                        ospf_hello_send(oi);

                        /* Restart hello timer for this interface */
                        THREAD_OFF(oi->t_hello);
                        OSPF_HELLO_TIMER_ON(oi);
                }

                return;
        }

        for (rn = route_top(IF_OIFS(ifp)); rn; rn = route_next(rn)) {
                struct ospf_interface *oi = rn->info;

                if (!oi)
                        continue;

                /* If hello interval configured on this oi, don't restart. */
                if (OSPF_IF_PARAM_CONFIGURED(oi->params, v_hello))
                        continue;

                /* Send hello before restart the hello timer
                 * to avoid session flaps in case of bigger
                 * hello interval configurations.
                 */
                ospf_hello_send(oi);

                /* Restart the hello timer. */
                THREAD_OFF(oi->t_hello);
                OSPF_HELLO_TIMER_ON(oi);
        }
}

void ospf_if_init(void)
{
        if_zapi_callbacks(ospf_ifp_create, ospf_ifp_up,
                          ospf_ifp_down, ospf_ifp_destroy);

        /* Initialize Zebra interface data structure. */
        hook_register_prio(if_add, 0, ospf_if_new_hook);
        hook_register_prio(if_del, 0, ospf_if_delete_hook);
}