Merge pull request #10928 from anlancs/zebra-cleanup-1

[mirror_frr.git] / ospfd / ospf_sr.c

/*
 * This is an implementation of Segment Routing
 * as per RFC 8665 - OSPF Extensions for Segment Routing
 * and RFC 8476 - Signaling Maximum SID Depth (MSD) Using OSPF
 *
 * Module name: Segment Routing
 *
 * Author: Olivier Dugeon <olivier.dugeon@orange.com>
 * Author: Anselme Sawadogo <anselmesawadogo@gmail.com>
 *
 * Copyright (C) 2016 - 2020 Orange Labs http://www.orange.com
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; see the file COPYING; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <zebra.h>

#include "printfrr.h"
#include "command.h"
#include "hash.h"
#include "if.h"
#include "if.h"
#include "jhash.h"
#include "libospf.h" /* for ospf interface types */
#include "linklist.h"
#include "log.h"
#include "memory.h"
#include "monotime.h"
#include "network.h"
#include "prefix.h"
#include "sockunion.h" /* for inet_aton() */
#include "stream.h"
#include "table.h"
#include "thread.h"
#include "vty.h"
#include "zclient.h"
#include "sbuf.h"
#include <lib/json.h>
#include "ospf_errors.h"

#include "ospfd/ospfd.h"
#include "ospfd/ospf_interface.h"
#include "ospfd/ospf_ism.h"
#include "ospfd/ospf_asbr.h"
#include "ospfd/ospf_lsa.h"
#include "ospfd/ospf_lsdb.h"
#include "ospfd/ospf_neighbor.h"
#include "ospfd/ospf_nsm.h"
#include "ospfd/ospf_flood.h"
#include "ospfd/ospf_packet.h"
#include "ospfd/ospf_spf.h"
#include "ospfd/ospf_dump.h"
#include "ospfd/ospf_route.h"
#include "ospfd/ospf_ase.h"
#include "ospfd/ospf_sr.h"
#include "ospfd/ospf_ri.h"
#include "ospfd/ospf_ext.h"
#include "ospfd/ospf_zebra.h"

/*
 * Global variable to manage Segment Routing on this node.
 * Note that all parameter values are stored in network byte order.
 */
static struct ospf_sr_db OspfSR;
static void ospf_sr_register_vty(void);
static inline void del_adj_sid(struct sr_nhlfe nhlfe);
static int ospf_sr_start(struct ospf *ospf);

/*
 * Segment Routing Data Base functions
 */

/* Hash function for Segment Routing entry */
static unsigned int sr_hash(const void *p)
{
        const struct in_addr *rid = p;

        return jhash_1word(rid->s_addr, 0);
}

/* Compare 2 Router ID hash entries based on SR Node */
static bool sr_cmp(const void *p1, const void *p2)
{
        const struct sr_node *srn = p1;
        const struct in_addr *rid = p2;

        return IPV4_ADDR_SAME(&srn->adv_router, rid);
}

/* Functions to remove an SR Link */
static void del_sr_link(void *val)
{
        struct sr_link *srl = (struct sr_link *)val;

        del_adj_sid(srl->nhlfe[0]);
        del_adj_sid(srl->nhlfe[1]);
        XFREE(MTYPE_OSPF_SR_PARAMS, val);
}

/* Functions to remove an SR Prefix */
static void del_sr_pref(void *val)
{
        struct sr_prefix *srp = (struct sr_prefix *)val;

        ospf_zebra_delete_prefix_sid(srp);
        XFREE(MTYPE_OSPF_SR_PARAMS, val);
}

/* Allocate new Segment Routine node */
static struct sr_node *sr_node_new(struct in_addr *rid)
{

        if (rid == NULL)
                return NULL;

        struct sr_node *new;

        /* Allocate Segment Routing node memory */
        new = XCALLOC(MTYPE_OSPF_SR_PARAMS, sizeof(struct sr_node));

        /* Default Algorithm, SRGB and MSD */
        for (int i = 0; i < ALGORITHM_COUNT; i++)
                new->algo[i] = SR_ALGORITHM_UNSET;

        new->srgb.range_size = 0;
        new->srgb.lower_bound = 0;
        new->msd = 0;

        /* Create Link, Prefix and Range TLVs list */
        new->ext_link = list_new();
        new->ext_prefix = list_new();
        new->ext_link->del = del_sr_link;
        new->ext_prefix->del = del_sr_pref;

        IPV4_ADDR_COPY(&new->adv_router, rid);
        new->neighbor = NULL;
        new->instance = 0;

        osr_debug("  |-  Created new SR node for %pI4", &new->adv_router);
        return new;
}

/* Supposed to be used for testing */
struct sr_node *ospf_sr_node_create(struct in_addr *rid)
{
        struct sr_node *srn;

        srn = hash_get(OspfSR.neighbors, (void *)rid, (void *)sr_node_new);

        return srn;
}

/* Delete Segment Routing node */
static void sr_node_del(struct sr_node *srn)
{
        /* Sanity Check */
        if (srn == NULL)
                return;

        osr_debug("  |- Delete SR node for %pI4", &srn->adv_router);

        /* Clean Extended Link */
        list_delete(&srn->ext_link);

        /* Clean Prefix List */
        list_delete(&srn->ext_prefix);

        XFREE(MTYPE_OSPF_SR_PARAMS, srn);
}

/* Get SR Node for a given nexthop */
static struct sr_node *get_sr_node_by_nexthop(struct ospf *ospf,
                                              struct in_addr nexthop)
{
        struct ospf_interface *oi = NULL;
        struct ospf_neighbor *nbr = NULL;
        struct listnode *node;
        struct route_node *rn;
        struct sr_node *srn;
        bool found;

        /* Sanity check */
        if (OspfSR.neighbors == NULL)
                return NULL;

        osr_debug("      |-  Search SR-Node for nexthop %pI4", &nexthop);

        /* First, search neighbor Router ID for this nexthop */
        found = false;
        for (ALL_LIST_ELEMENTS_RO(ospf->oiflist, node, oi)) {
                for (rn = route_top(oi->nbrs); rn; rn = route_next(rn)) {
                        nbr = rn->info;
                        if ((nbr) && (IPV4_ADDR_SAME(&nexthop, &nbr->src))) {
                                found = true;
                                break;
                        }
                }
                if (found)
                        break;
        }

        if (!found)
                return NULL;

        osr_debug("      |-  Found nexthop Router ID %pI4", &nbr->router_id);

        /* Then, search SR Node */
        srn = (struct sr_node *)hash_lookup(OspfSR.neighbors, &nbr->router_id);

        return srn;
}

/*
 * Segment Routing Local Block management functions
 */

/**
 * It is necessary to known which label is already allocated to manage the range
 * of SRLB. This is particular useful when an interface flap (goes up / down
 * frequently). Here, SR will release and then allocate label for the Adjacency
 * for each concerned interface. If we don't care, there is a risk to run out of
 * label.
 *
 * For that purpose, a similar principle as already provided to manage chunk of
 * label is proposed. But, here, the label chunk has not a fix range of 64
 * labels that could be easily manage with a single variable of 64 bits size.
 * So, used_mark is used as a bit wise to mark label reserved (bit set) or not
 * (bit unset). Its size is equal to the number of label of the SRLB range round
 * up to 64 bits.
 *
 *  - sr__local_block_init() computes the number of 64 bits variables that are
 *    needed to manage the SRLB range and allocates this number.
 *  - ospf_sr_local_block_request_label() pick up the first available label and
 *    set corresponding bit
 *  - ospf_sr_local_block_release_label() release label by reseting the
 *    corresponding bit and set the next label to the first free position
 */

/**
 * Initialize Segment Routing Local Block from SRDB configuration and reserve
 * block of bits to manage label allocation.
 *
 * @param lower_bound   The lower bound of the SRLB range
 * @param upper_bound   The upper bound of the SRLB range
 *
 * @return              0 on success, -1 otherwise
 */
static int sr_local_block_init(uint32_t lower_bound, uint32_t upper_bound)
{
        struct sr_local_block *srlb = &OspfSR.srlb;
        uint32_t size;

        /* Check if SRLB is not already configured */
        if (srlb->reserved)
                return 0;

        /*
         * Request SRLB to the label manager. If the allocation fails, return
         * an error to disable SR until a new SRLB is successfully allocated.
         */
        size = upper_bound - lower_bound + 1;
        if (ospf_zebra_request_label_range(lower_bound, size)) {
                zlog_err("SR: Error reserving SRLB [%u/%u] %u labels",
                         lower_bound, upper_bound, size);
                return -1;
        }

        osr_debug("SR: Got new SRLB [%u/%u], %u labels", lower_bound,
                  upper_bound, size);

        /* Initialize the SRLB */
        srlb->start = lower_bound;
        srlb->end = upper_bound;
        srlb->current = 0;

        /* Compute the needed Used Mark number and allocate them */
        srlb->max_block = size / SRLB_BLOCK_SIZE;
        if ((size % SRLB_BLOCK_SIZE) != 0)
                srlb->max_block++;
        srlb->used_mark = XCALLOC(MTYPE_OSPF_SR_PARAMS,
                                  srlb->max_block * SRLB_BLOCK_SIZE);
        srlb->reserved = true;

        return 0;
}

static int sr_global_block_init(uint32_t start, uint32_t size)
{
        struct sr_global_block *srgb = &OspfSR.srgb;

        /* Check if already configured */
        if (srgb->reserved)
                return 0;

        /* request chunk */
        uint32_t end = start + size - 1;
        if (ospf_zebra_request_label_range(start, size) < 0) {
                zlog_err("SR: Error reserving SRGB [%u/%u], %u labels", start,
                         end, size);
                return -1;
        }

        osr_debug("SR: Got new SRGB [%u/%u], %u labels", start, end, size);

        /* success */
        srgb->start = start;
        srgb->size = size;
        srgb->reserved = true;
        return 0;
}

/**
 * Remove Segment Routing Local Block.
 *
 */
static void sr_local_block_delete(void)
{
        struct sr_local_block *srlb = &OspfSR.srlb;

        /* Check if SRLB is not already delete */
        if (!srlb->reserved)
                return;

        osr_debug("SR (%s): Remove SRLB [%u/%u]", __func__, srlb->start,
                  srlb->end);

        /* First release the label block */
        ospf_zebra_release_label_range(srlb->start, srlb->end);

        /* Then reset SRLB structure */
        if (srlb->used_mark != NULL)
                XFREE(MTYPE_OSPF_SR_PARAMS, srlb->used_mark);

        srlb->reserved = false;
}

/**
 * Remove Segment Routing Global block
 */
static void sr_global_block_delete(void)
{
        struct sr_global_block *srgb = &OspfSR.srgb;

        if (!srgb->reserved)
                return;

        osr_debug("SR (%s): Remove SRGB [%u/%u]", __func__, srgb->start,
                  srgb->start + srgb->size - 1);

        ospf_zebra_release_label_range(srgb->start,
                                       srgb->start + srgb->size - 1);

        srgb->reserved = false;
}


/**
 * Request a label from the Segment Routing Local Block.
 *
 * @return      First available label on success or MPLS_INVALID_LABEL if the
 *              block of labels is full
 */
mpls_label_t ospf_sr_local_block_request_label(void)
{
        struct sr_local_block *srlb = &OspfSR.srlb;
        mpls_label_t label;
        uint32_t index;
        uint32_t pos;
        uint32_t size = srlb->end - srlb->start + 1;

        /* Check if we ran out of available labels */
        if (srlb->current >= size)
                return MPLS_INVALID_LABEL;

        /* Get first available label and mark it used */
        label = srlb->current + srlb->start;
        index = srlb->current / SRLB_BLOCK_SIZE;
        pos = 1ULL << (srlb->current % SRLB_BLOCK_SIZE);
        srlb->used_mark[index] |= pos;

        /* Jump to the next free position */
        srlb->current++;
        pos = srlb->current % SRLB_BLOCK_SIZE;
        while (srlb->current < size) {
                if (pos == 0)
                        index++;
                if (!((1ULL << pos) & srlb->used_mark[index]))
                        break;
                else {
                        srlb->current++;
                        pos = srlb->current % SRLB_BLOCK_SIZE;
                }
        }

        if (srlb->current == size)
                zlog_warn(
                        "SR: Warning, SRLB is depleted and next label request will fail");

        return label;
}

/**
 * Release label in the Segment Routing Local Block.
 *
 * @param label Label to be release
 *
 * @return      0 on success or -1 if label falls outside SRLB
 */
int ospf_sr_local_block_release_label(mpls_label_t label)
{
        struct sr_local_block *srlb = &OspfSR.srlb;
        uint32_t index;
        uint32_t pos;

        /* Check that label falls inside the SRLB */
        if ((label < srlb->start) || (label > srlb->end)) {
                flog_warn(EC_OSPF_SR_SID_OVERFLOW,
                          "%s: Returning label %u is outside SRLB [%u/%u]",
                          __func__, label, srlb->start, srlb->end);
                return -1;
        }

        index = (label - srlb->start) / SRLB_BLOCK_SIZE;
        pos = 1ULL << ((label - srlb->start) % SRLB_BLOCK_SIZE);
        srlb->used_mark[index] &= ~pos;
        /* Reset current to the first available position */
        for (index = 0; index < srlb->max_block; index++) {
                if (srlb->used_mark[index] != 0xFFFFFFFFFFFFFFFF) {
                        for (pos = 0; pos < SRLB_BLOCK_SIZE; pos++)
                                if (!((1ULL << pos) & srlb->used_mark[index])) {
                                        srlb->current =
                                                index * SRLB_BLOCK_SIZE + pos;
                                        break;
                                }
                        break;
                }
        }

        return 0;
}

/*
 * Segment Routing Initialization functions
 */

/**
 * Thread function to re-attempt connection to the Label Manager and thus be
 * able to start Segment Routing.
 *
 * @param start         Thread structure that contains area as argument
 *
 * @return              1 on success
 */
static void sr_start_label_manager(struct thread *start)
{
        struct ospf *ospf;

        ospf = THREAD_ARG(start);

        /* re-attempt to start SR & Label Manager connection */
        ospf_sr_start(ospf);
}

/* Segment Routing starter function */
static int ospf_sr_start(struct ospf *ospf)
{
        struct route_node *rn;
        struct ospf_lsa *lsa;
        struct sr_node *srn;
        int rc = 0;

        osr_debug("SR (%s): Start Segment Routing", __func__);

        /* Initialize self SR Node if not already done */
        if (OspfSR.self == NULL) {
                srn = hash_get(OspfSR.neighbors, (void *)&(ospf->router_id),
                               (void *)sr_node_new);

                /* Complete & Store self SR Node */
                srn->srgb.range_size = OspfSR.srgb.size;
                srn->srgb.lower_bound = OspfSR.srgb.start;
                srn->srlb.lower_bound = OspfSR.srlb.start;
                srn->srlb.range_size = OspfSR.srlb.end - OspfSR.srlb.start + 1;
                srn->algo[0] = OspfSR.algo[0];
                srn->msd = OspfSR.msd;
                OspfSR.self = srn;
        }

        /* Then, start Label Manager if not ready */
        if (!ospf_zebra_label_manager_ready())
                if (ospf_zebra_label_manager_connect() < 0) {
                        /* Re-attempt to connect to Label Manager in 1 sec. */
                        thread_add_timer(master, sr_start_label_manager, ospf,
                                         1, &OspfSR.t_start_lm);
                        osr_debug("  |- Failed to start the Label Manager");
                        return -1;
                }

        /*
         * Request SRLB & SGRB to the label manager if not already reserved.
         * If the allocation fails, return an error to disable SR until a new
         * SRLB and/or SRGB are successfully allocated.
         */
        if (sr_local_block_init(OspfSR.srlb.start, OspfSR.srlb.end) < 0)
                return -1;

        if (sr_global_block_init(OspfSR.srgb.start, OspfSR.srgb.size) < 0)
                return -1;

        /* SR is UP and ready to flood LSA */
        OspfSR.status = SR_UP;

        /* Set Router Information SR parameters */
        osr_debug("SR: Activate SR for Router Information LSA");

        ospf_router_info_update_sr(true, OspfSR.self);

        /* Update Ext LSA */
        osr_debug("SR: Activate SR for Extended Link/Prefix LSA");

        ospf_ext_update_sr(true);

        osr_debug("SR (%s): Update SR-DB from LSDB", __func__);

        /* Start by looking to Router Info & Extended LSA in lsdb */
        if ((ospf != NULL) && (ospf->backbone != NULL)) {
                LSDB_LOOP (OPAQUE_AREA_LSDB(ospf->backbone), rn, lsa) {
                        if (IS_LSA_MAXAGE(lsa) || IS_LSA_SELF(lsa))
                                continue;
                        int lsa_id =
                                GET_OPAQUE_TYPE(ntohl(lsa->data->id.s_addr));
                        switch (lsa_id) {
                        case OPAQUE_TYPE_ROUTER_INFORMATION_LSA:
                                ospf_sr_ri_lsa_update(lsa);
                                break;
                        case OPAQUE_TYPE_EXTENDED_PREFIX_LSA:
                                ospf_sr_ext_prefix_lsa_update(lsa);
                                break;
                        case OPAQUE_TYPE_EXTENDED_LINK_LSA:
                                ospf_sr_ext_link_lsa_update(lsa);
                                break;
                        default:
                                break;
                        }
                }
        }

        rc = 1;
        return rc;
}

/* Stop Segment Routing */
static void ospf_sr_stop(void)
{

        if (OspfSR.status == SR_OFF)
                return;

        osr_debug("SR (%s): Stop Segment Routing", __func__);

        /* Disable any re-attempt to connect to Label Manager */
        THREAD_OFF(OspfSR.t_start_lm);

        /* Release SRGB if active */
        sr_global_block_delete();

        /* Release SRLB if active */
        sr_local_block_delete();

        /*
         * Remove all SR Nodes from the Hash table. Prefix and Link SID will
         * be remove though list_delete() call. See sr_node_del()
         */
        hash_clean(OspfSR.neighbors, (void *)sr_node_del);
        OspfSR.self = NULL;
        OspfSR.status = SR_OFF;
}

/*
 * Segment Routing initialize function
 *
 * @param - nothing
 *
 * @return 0 if OK, -1 otherwise
 */
int ospf_sr_init(void)
{
        int rc = -1;

        osr_debug("SR (%s): Initialize SR Data Base", __func__);

        memset(&OspfSR, 0, sizeof(struct ospf_sr_db));
        OspfSR.status = SR_OFF;
        /* Only AREA flooding is supported in this release */
        OspfSR.scope = OSPF_OPAQUE_AREA_LSA;

        /* Initialize Algorithms, SRGB, SRLB and MSD TLVs */
        /* Only Algorithm SPF is supported */
        OspfSR.algo[0] = SR_ALGORITHM_SPF;
        for (int i = 1; i < ALGORITHM_COUNT; i++)
                OspfSR.algo[i] = SR_ALGORITHM_UNSET;

        OspfSR.srgb.size = DEFAULT_SRGB_SIZE;
        OspfSR.srgb.start = DEFAULT_SRGB_LABEL;
        OspfSR.srgb.reserved = false;

        OspfSR.srlb.start = DEFAULT_SRLB_LABEL;
        OspfSR.srlb.end = DEFAULT_SRLB_END;
        OspfSR.srlb.reserved = false;
        OspfSR.msd = 0;

        /* Initialize Hash table for neighbor SR nodes */
        OspfSR.neighbors = hash_create(sr_hash, sr_cmp, "OSPF_SR");
        if (OspfSR.neighbors == NULL)
                return rc;

        /* Register Segment Routing VTY command */
        ospf_sr_register_vty();

        rc = 0;
        return rc;
}

/*
 * Segment Routing termination function
 *
 * @param - nothing
 * @return - nothing
 */
void ospf_sr_term(void)
{

        /* Stop Segment Routing */
        ospf_sr_stop();

        /* Clear SR Node Table */
        if (OspfSR.neighbors)
                hash_free(OspfSR.neighbors);

}

/*
 * Segment Routing finish function
 *
 * @param - nothing
 * @return - nothing
 */
void ospf_sr_finish(void)
{
        /* Stop Segment Routing */
        ospf_sr_stop();
}

/*
 * Following functions are used to manipulate the
 * Next Hop Label Forwarding entry (NHLFE)
 */

/* Compute label from index */
static mpls_label_t index2label(uint32_t index, struct sr_block srgb)
{
        mpls_label_t label;

        label = srgb.lower_bound + index;
        if (label > (srgb.lower_bound + srgb.range_size)) {
                flog_warn(EC_OSPF_SR_SID_OVERFLOW,
                          "%s: SID index %u falls outside SRGB range",
                          __func__, index);
                return MPLS_INVALID_LABEL;
        } else
                return label;
}

/* Get the prefix sid for a specific router id */
mpls_label_t ospf_sr_get_prefix_sid_by_id(struct in_addr *id)
{
        struct sr_node *srn;
        struct sr_prefix *srp;
        mpls_label_t label;

        srn = (struct sr_node *)hash_lookup(OspfSR.neighbors, id);

        if (srn) {
                /*
                 * TODO: Here we assume that the SRGBs are the same,
                 * and that the node's prefix SID is at the head of
                 * the list, probably needs tweaking.
                 */
                srp = listnode_head(srn->ext_prefix);
                label = index2label(srp->sid, srn->srgb);
        } else {
                label = MPLS_INVALID_LABEL;
        }

        return label;
}

/* Get the adjacency sid for a specific 'root' id and 'neighbor' id */
mpls_label_t ospf_sr_get_adj_sid_by_id(struct in_addr *root_id,
                                       struct in_addr *neighbor_id)
{
        struct sr_node *srn;
        struct sr_link *srl;
        mpls_label_t label;
        struct listnode *node;

        srn = (struct sr_node *)hash_lookup(OspfSR.neighbors, root_id);

        label = MPLS_INVALID_LABEL;

        if (srn) {
                for (ALL_LIST_ELEMENTS_RO(srn->ext_link, node, srl)) {
                        if (srl->type == ADJ_SID
                            && srl->remote_id.s_addr == neighbor_id->s_addr) {
                                label = srl->sid[0];
                                break;
                        }
                }
        }

        return label;
}

/* Get neighbor full structure from address */
static struct ospf_neighbor *get_neighbor_by_addr(struct ospf *top,
                                                  struct in_addr addr)
{
        struct ospf_neighbor *nbr;
        struct ospf_interface *oi;
        struct listnode *node;
        struct route_node *rn;

        /* Sanity Check */
        if (top == NULL)
                return NULL;

        for (ALL_LIST_ELEMENTS_RO(top->oiflist, node, oi))
                for (rn = route_top(oi->nbrs); rn; rn = route_next(rn)) {
                        nbr = rn->info;
                        if (nbr)
                                if (IPV4_ADDR_SAME(&nbr->address.u.prefix4,
                                                   &addr)
                                    || IPV4_ADDR_SAME(&nbr->router_id, &addr)) {
                                        route_unlock_node(rn);
                                        return nbr;
                                }
                }
        return NULL;
}

/* Get OSPF Path from address */
static struct ospf_route *get_nexthop_by_addr(struct ospf *top,
                                              struct prefix_ipv4 p)
{
        struct route_node *rn;

        /* Sanity Check */
        if (top == NULL)
                return NULL;

        osr_debug("      |-  Search Nexthop for prefix %pFX",
                  (struct prefix *)&p);

        rn = route_node_lookup(top->new_table, (struct prefix *)&p);

        /*
         * Check if we found an OSPF route. May be NULL if SPF has not
         * yet populate routing table for this prefix.
         */
        if (rn == NULL)
                return NULL;

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

/* Compute NHLFE entry for Extended Link */
static int compute_link_nhlfe(struct sr_link *srl)
{
        struct ospf *top = ospf_lookup_by_vrf_id(VRF_DEFAULT);
        struct ospf_neighbor *nh;
        int rc = 0;

        osr_debug("    |-  Compute NHLFE for link %pI4", &srl->itf_addr);

        /* First determine the OSPF Neighbor */
        nh = get_neighbor_by_addr(top, srl->nhlfe[0].nexthop);

        /* Neighbor could be not found when OSPF Adjacency just fire up
         * because SPF don't yet populate routing table. This NHLFE will
         * be fixed later when SR SPF schedule will be called.
         */
        if (nh == NULL)
                return rc;

        osr_debug("    |-  Found nexthop %pI4", &nh->router_id);

        /* Set ifindex for this neighbor */
        srl->nhlfe[0].ifindex = nh->oi->ifp->ifindex;
        srl->nhlfe[1].ifindex = nh->oi->ifp->ifindex;

        /* Update neighbor address for LAN_ADJ_SID */
        if (srl->type == LAN_ADJ_SID) {
                IPV4_ADDR_COPY(&srl->nhlfe[0].nexthop, &nh->src);
                IPV4_ADDR_COPY(&srl->nhlfe[1].nexthop, &nh->src);
        }

        /* Set Input & Output Label */
        if (CHECK_FLAG(srl->flags[0], EXT_SUBTLV_LINK_ADJ_SID_VFLG))
                srl->nhlfe[0].label_in = srl->sid[0];
        else
                srl->nhlfe[0].label_in =
                        index2label(srl->sid[0], srl->srn->srgb);
        if (CHECK_FLAG(srl->flags[1], EXT_SUBTLV_LINK_ADJ_SID_VFLG))
                srl->nhlfe[1].label_in = srl->sid[1];
        else
                srl->nhlfe[1].label_in =
                        index2label(srl->sid[1], srl->srn->srgb);

        srl->nhlfe[0].label_out = MPLS_LABEL_IMPLICIT_NULL;
        srl->nhlfe[1].label_out = MPLS_LABEL_IMPLICIT_NULL;

        rc = 1;
        return rc;
}

/**
 * Compute output label for the given Prefix-SID.
 *
 * @param srp           Segment Routing Prefix
 * @param srnext        Segment Routing nexthop node
 *
 * @return              MPLS label or MPLS_INVALID_LABEL in case of error
 */
static mpls_label_t sr_prefix_out_label(const struct sr_prefix *srp,
                                        const struct sr_node *srnext)
{
        /* Check if the nexthop SR Node is the last hop? */
        if (srnext == srp->srn) {
                /* SR-Node doesn't request NO-PHP. Return Implicit NULL label */
                if (!CHECK_FLAG(srp->flags, EXT_SUBTLV_PREFIX_SID_NPFLG))
                        return MPLS_LABEL_IMPLICIT_NULL;

                /* SR-Node requests Explicit NULL Label */
                if (CHECK_FLAG(srp->flags, EXT_SUBTLV_PREFIX_SID_EFLG))
                        return MPLS_LABEL_IPV4_EXPLICIT_NULL;
                /* Fallthrough */
        }

        /* Return SID value as MPLS label if it is an Absolute SID */
        if (CHECK_FLAG(srp->flags, EXT_SUBTLV_PREFIX_SID_VFLG
                                           | EXT_SUBTLV_PREFIX_SID_LFLG)) {
                /*
                 * V/L SIDs have local significance, so only adjacent routers
                 * can use them (RFC8665 section #5)
                 */
                if (srp->srn != srnext)
                        return MPLS_INVALID_LABEL;
                return srp->sid;
        }

        /* Return MPLS label as SRGB lower bound + SID index as per RFC 8665 */
        return (index2label(srp->sid, srnext->srgb));
}

/*
 * Compute NHLFE entry for Extended Prefix
 *
 * @param srp - Segment Routing Prefix
 *
 * @return -1 if no route is found, 0 if there is no SR route ready
 *         and 1 if success or update
 */
static int compute_prefix_nhlfe(struct sr_prefix *srp)
{
        struct ospf *top = ospf_lookup_by_vrf_id(VRF_DEFAULT);
        struct ospf_path *path;
        struct listnode *node;
        struct sr_node *srnext;
        int rc = -1;

        osr_debug("    |-  Compute NHLFE for prefix %pFX",
                  (struct prefix *)&srp->prefv4);


        /* First determine the nexthop */
        srp->route = get_nexthop_by_addr(top, srp->prefv4);

        /* Nexthop could be not found when OSPF Adjacency just fire up
         * because SPF don't yet populate routing table. This NHLFE will
         * be fixed later when SR SPF schedule will be called.
         */
        if (srp->route == NULL)
                return rc;

        /* Compute Input Label with self SRGB */
        srp->label_in = index2label(srp->sid, OspfSR.self->srgb);

        rc = 0;
        for (ALL_LIST_ELEMENTS_RO(srp->route->paths, node, path)) {

                osr_debug("    |-  Process new route via %pI4 for this prefix",
                          &path->nexthop);

                /*
                 * Get SR-Node for this nexthop. Could be not yet available
                 * as Extended Link / Prefix and Router Information are flooded
                 * after LSA Type 1 & 2 which populate the OSPF Route Table
                 */
                srnext = get_sr_node_by_nexthop(top, path->nexthop);
                if (srnext == NULL)
                        continue;

                /* And store this information for later update */
                srnext->neighbor = OspfSR.self;
                path->srni.nexthop = srnext;

                /*
                 * SR Node could be known, but SRGB could be not initialize
                 * This is due to the fact that Extended Link / Prefix could
                 * be received before corresponding Router Information LSA
                 */
                if (srnext == NULL || srnext->srgb.lower_bound == 0
                    || srnext->srgb.range_size == 0) {
                        osr_debug(
                                "    |-  SR-Node %pI4 not ready. Stop process",
                                &srnext->adv_router);
                        path->srni.label_out = MPLS_INVALID_LABEL;
                        continue;
                }

                osr_debug("    |-  Found SRGB %u/%u for next hop SR-Node %pI4",
                          srnext->srgb.range_size, srnext->srgb.lower_bound,
                          &srnext->adv_router);

                /* Compute Output Label with Nexthop SR Node SRGB */
                path->srni.label_out = sr_prefix_out_label(srp, srnext);

                osr_debug("    |-  Computed new labels in: %u out: %u",
                          srp->label_in, path->srni.label_out);
                rc = 1;
        }
        return rc;
}

/* Add new NHLFE entry for Adjacency SID */
static inline void add_adj_sid(struct sr_nhlfe nhlfe)
{
        if (nhlfe.label_in != 0)
                ospf_zebra_send_adjacency_sid(ZEBRA_MPLS_LABELS_ADD, nhlfe);
}

/* Remove NHLFE entry for Adjacency SID */
static inline void del_adj_sid(struct sr_nhlfe nhlfe)
{
        if (nhlfe.label_in != 0)
                ospf_zebra_send_adjacency_sid(ZEBRA_MPLS_LABELS_DELETE, nhlfe);
}

/* Update NHLFE entry for Adjacency SID */
static inline void update_adj_sid(struct sr_nhlfe n1, struct sr_nhlfe n2)
{
        del_adj_sid(n1);
        add_adj_sid(n2);
}

/*
 * Functions to parse and get Extended Link / Prefix
 * TLVs and SubTLVs
 */

/* Extended Link SubTLVs Getter */
static struct sr_link *get_ext_link_sid(struct tlv_header *tlvh, size_t size)
{

        struct sr_link *srl;
        struct ext_tlv_link *link = (struct ext_tlv_link *)tlvh;
        struct ext_subtlv_adj_sid *adj_sid;
        struct ext_subtlv_lan_adj_sid *lan_sid;
        struct ext_subtlv_rmt_itf_addr *rmt_itf;

        struct tlv_header *sub_tlvh;
        uint16_t length = 0, sum = 0, i = 0;

        /* Check TLV size */
        if ((ntohs(tlvh->length) > size)
            || ntohs(tlvh->length) < EXT_TLV_LINK_SIZE) {
                zlog_warn("Wrong Extended Link TLV size. Abort!");
                return NULL;
        }

        srl = XCALLOC(MTYPE_OSPF_SR_PARAMS, sizeof(struct sr_link));

        /* Initialize TLV browsing */
        length = ntohs(tlvh->length) - EXT_TLV_LINK_SIZE;
        sub_tlvh = (struct tlv_header *)((char *)(tlvh) + TLV_HDR_SIZE
                                         + EXT_TLV_LINK_SIZE);
        for (; sum < length && sub_tlvh; sub_tlvh = TLV_HDR_NEXT(sub_tlvh)) {
                switch (ntohs(sub_tlvh->type)) {
                case EXT_SUBTLV_ADJ_SID:
                        adj_sid = (struct ext_subtlv_adj_sid *)sub_tlvh;
                        srl->type = ADJ_SID;
                        i = CHECK_FLAG(adj_sid->flags,
                                       EXT_SUBTLV_LINK_ADJ_SID_BFLG)
                                    ? 1
                                    : 0;
                        srl->flags[i] = adj_sid->flags;
                        if (CHECK_FLAG(adj_sid->flags,
                                       EXT_SUBTLV_LINK_ADJ_SID_VFLG))
                                srl->sid[i] = GET_LABEL(ntohl(adj_sid->value));
                        else
                                srl->sid[i] = ntohl(adj_sid->value);
                        IPV4_ADDR_COPY(&srl->nhlfe[i].nexthop, &link->link_id);
                        break;
                case EXT_SUBTLV_LAN_ADJ_SID:
                        lan_sid = (struct ext_subtlv_lan_adj_sid *)sub_tlvh;
                        srl->type = LAN_ADJ_SID;
                        i = CHECK_FLAG(lan_sid->flags,
                                       EXT_SUBTLV_LINK_ADJ_SID_BFLG)
                                    ? 1
                                    : 0;
                        srl->flags[i] = lan_sid->flags;
                        if (CHECK_FLAG(lan_sid->flags,
                                       EXT_SUBTLV_LINK_ADJ_SID_VFLG))
                                srl->sid[i] = GET_LABEL(ntohl(lan_sid->value));
                        else
                                srl->sid[i] = ntohl(lan_sid->value);
                        IPV4_ADDR_COPY(&srl->nhlfe[i].nexthop,
                                       &lan_sid->neighbor_id);
                        break;
                case EXT_SUBTLV_RMT_ITF_ADDR:
                        rmt_itf = (struct ext_subtlv_rmt_itf_addr *)sub_tlvh;
                        IPV4_ADDR_COPY(&srl->nhlfe[0].nexthop, &rmt_itf->value);
                        IPV4_ADDR_COPY(&srl->nhlfe[1].nexthop, &rmt_itf->value);
                        break;
                default:
                        break;
                }
                sum += TLV_SIZE(sub_tlvh);
        }

        IPV4_ADDR_COPY(&srl->itf_addr, &link->link_data);

        osr_debug("  |-  Found primary %u and backup %u Adj/Lan Sid for %pI4",
                  srl->sid[0], srl->sid[1], &srl->itf_addr);

        return srl;
}

/* Extended Prefix SubTLVs Getter */
static struct sr_prefix *get_ext_prefix_sid(struct tlv_header *tlvh,
                                            size_t size)
{

        struct sr_prefix *srp;
        struct ext_tlv_prefix *pref = (struct ext_tlv_prefix *)tlvh;
        struct ext_subtlv_prefix_sid *psid;

        struct tlv_header *sub_tlvh;
        uint16_t length = 0, sum = 0;

        /* Check TLV size */
        if ((ntohs(tlvh->length) > size)
            || ntohs(tlvh->length) < EXT_TLV_PREFIX_SIZE) {
                zlog_warn("Wrong Extended Link TLV size. Abort!");
                return NULL;
        }

        srp = XCALLOC(MTYPE_OSPF_SR_PARAMS, sizeof(struct sr_prefix));

        /* Initialize TLV browsing */
        length = ntohs(tlvh->length) - EXT_TLV_PREFIX_SIZE;
        sub_tlvh = (struct tlv_header *)((char *)(tlvh) + TLV_HDR_SIZE
                                         + EXT_TLV_PREFIX_SIZE);
        for (; sum < length && sub_tlvh; sub_tlvh = TLV_HDR_NEXT(sub_tlvh)) {
                switch (ntohs(sub_tlvh->type)) {
                case EXT_SUBTLV_PREFIX_SID:
                        psid = (struct ext_subtlv_prefix_sid *)sub_tlvh;
                        if (psid->algorithm != SR_ALGORITHM_SPF) {
                                flog_err(EC_OSPF_INVALID_ALGORITHM,
                                         "SR (%s): Unsupported Algorithm",
                                         __func__);
                                XFREE(MTYPE_OSPF_SR_PARAMS, srp);
                                return NULL;
                        }
                        srp->type = PREF_SID;
                        srp->flags = psid->flags;
                        if (CHECK_FLAG(psid->flags, EXT_SUBTLV_PREFIX_SID_VFLG))
                                srp->sid = GET_LABEL(ntohl(psid->value));
                        else
                                srp->sid = ntohl(psid->value);
                        IPV4_ADDR_COPY(&srp->prefv4.prefix, &pref->address);
                        srp->prefv4.prefixlen = pref->pref_length;
                        srp->prefv4.family = AF_INET;
                        apply_mask_ipv4(&srp->prefv4);
                        break;
                default:
                        break;
                }
                sum += TLV_SIZE(sub_tlvh);
        }

        osr_debug("  |-  Found SID %u for prefix %pFX", srp->sid,
                  (struct prefix *)&srp->prefv4);

        return srp;
}

/*
 * Functions to manipulate Segment Routing Link & Prefix structures
 */

/* Compare two Segment Link: return 0 if equal, 1 otherwise */
static inline int sr_link_cmp(struct sr_link *srl1, struct sr_link *srl2)
{
        if ((srl1->sid[0] == srl2->sid[0]) && (srl1->sid[1] == srl2->sid[1])
            && (srl1->type == srl2->type) && (srl1->flags[0] == srl2->flags[0])
            && (srl1->flags[1] == srl2->flags[1]))
                return 0;
        else
                return 1;
}

/* Compare two Segment Prefix: return 0 if equal, 1 otherwise */
static inline int sr_prefix_cmp(struct sr_prefix *srp1, struct sr_prefix *srp2)
{
        if ((srp1->sid == srp2->sid) && (srp1->flags == srp2->flags))
                return 0;
        else
                return 1;
}

/* Update Segment Link of given Segment Routing Node */
static void update_ext_link_sid(struct sr_node *srn, struct sr_link *srl,
                                uint8_t lsa_flags)
{
        struct listnode *node;
        struct sr_link *lk;
        bool found = false;
        bool config = true;

        /* Sanity check */
        if ((srn == NULL) || (srl == NULL))
                return;

        osr_debug("  |-  Process Extended Link Adj/Lan-SID");

        /* Detect if Adj/Lan_Adj SID must be configured */
        if (!CHECK_FLAG(lsa_flags, OSPF_LSA_SELF)
            && (CHECK_FLAG(srl->flags[0], EXT_SUBTLV_LINK_ADJ_SID_LFLG)
                || CHECK_FLAG(srl->flags[1], EXT_SUBTLV_LINK_ADJ_SID_LFLG)))
                config = false;

        /* Search for existing Segment Link */
        for (ALL_LIST_ELEMENTS_RO(srn->ext_link, node, lk))
                if (lk->instance == srl->instance) {
                        found = true;
                        break;
                }

        osr_debug("  |-  %s SR Link 8.0.0.%u for SR node %pI4",
                  found ? "Update" : "Add", GET_OPAQUE_ID(srl->instance),
                  &srn->adv_router);

        /* if not found, add new Segment Link and install NHLFE */
        if (!found) {
                /* Complete SR-Link and add it to SR-Node list */
                srl->srn = srn;
                IPV4_ADDR_COPY(&srl->adv_router, &srn->adv_router);
                listnode_add(srn->ext_link, srl);
                /* Try to set MPLS table */
                if (config && compute_link_nhlfe(srl)) {
                        add_adj_sid(srl->nhlfe[0]);
                        add_adj_sid(srl->nhlfe[1]);
                }
        } else {
                /* Update SR-Link if they are different */
                if (sr_link_cmp(lk, srl)) {
                        /* Try to set MPLS table */
                        if (config) {
                                if (compute_link_nhlfe(srl)) {
                                        update_adj_sid(lk->nhlfe[0],
                                                       srl->nhlfe[0]);
                                        update_adj_sid(lk->nhlfe[1],
                                                       srl->nhlfe[1]);
                                } else {
                                        del_adj_sid(lk->nhlfe[0]);
                                        del_adj_sid(lk->nhlfe[1]);
                                }
                        }
                        /* Replace SR-Link in SR-Node Adjacency List */
                        listnode_delete(srn->ext_link, lk);
                        XFREE(MTYPE_OSPF_SR_PARAMS, lk);
                        srl->srn = srn;
                        IPV4_ADDR_COPY(&srl->adv_router, &srn->adv_router);
                        listnode_add(srn->ext_link, srl);
                } else {
                        /*
                         * This is just an LSA refresh.
                         * Stop processing and free SR Link
                         */
                        XFREE(MTYPE_OSPF_SR_PARAMS, srl);
                }
        }
}

/* Update Segment Prefix of given Segment Routing Node */
static void update_ext_prefix_sid(struct sr_node *srn, struct sr_prefix *srp)
{

        struct listnode *node;
        struct sr_prefix *pref;
        bool found = false;

        /* Sanity check */
        if (srn == NULL || srp == NULL)
                return;

        osr_debug("  |-  Process Extended Prefix SID %u", srp->sid);

        /* Process only Global Prefix SID */
        if (CHECK_FLAG(srp->flags, EXT_SUBTLV_PREFIX_SID_LFLG))
                return;

        /* Search for existing Segment Prefix */
        for (ALL_LIST_ELEMENTS_RO(srn->ext_prefix, node, pref))
                if (pref->instance == srp->instance
                    && prefix_same((struct prefix *)&srp->prefv4,
                                   &pref->prefv4)) {
                        found = true;
                        break;
                }

        osr_debug("  |-  %s SR LSA ID 7.0.0.%u for SR node %pI4",
                  found ? "Update" : "Add", GET_OPAQUE_ID(srp->instance),
                  &srn->adv_router);

        /* Complete SR-Prefix */
        srp->srn = srn;
        IPV4_ADDR_COPY(&srp->adv_router, &srn->adv_router);

        /* if not found, add new Segment Prefix and install NHLFE */
        if (!found) {
                /* Add it to SR-Node list ... */
                listnode_add(srn->ext_prefix, srp);
                /* ... and try to set MPLS table */
                if (compute_prefix_nhlfe(srp) == 1)
                        ospf_zebra_update_prefix_sid(srp);
        } else {
                /*
                 * An old SR prefix exist. Check if something changes or if it
                 * is just a refresh.
                 */
                if (sr_prefix_cmp(pref, srp)) {
                        if (compute_prefix_nhlfe(srp) == 1) {
                                ospf_zebra_delete_prefix_sid(pref);
                                /* Replace Segment Prefix */
                                listnode_delete(srn->ext_prefix, pref);
                                XFREE(MTYPE_OSPF_SR_PARAMS, pref);
                                listnode_add(srn->ext_prefix, srp);
                                ospf_zebra_update_prefix_sid(srp);
                        } else {
                                /* New NHLFE was not found.
                                 * Just free the SR Prefix
                                 */
                                XFREE(MTYPE_OSPF_SR_PARAMS, srp);
                        }
                } else {
                        /* This is just an LSA refresh.
                         * Stop processing and free SR Prefix
                         */
                        XFREE(MTYPE_OSPF_SR_PARAMS, srp);
                }
        }
}

/*
 * When change the FRR Self SRGB, update the NHLFE Input Label
 * for all Extended Prefix with SID index through hash_iterate()
 */
static void update_in_nhlfe(struct hash_bucket *bucket, void *args)
{
        struct listnode *node;
        struct sr_node *srn = (struct sr_node *)bucket->data;
        struct sr_prefix *srp;

        /* Process Every Extended Prefix for this SR-Node */
        for (ALL_LIST_ELEMENTS_RO(srn->ext_prefix, node, srp)) {
                /* Process Self SRN only if NO-PHP is requested */
                if ((srn == OspfSR.self)
                    && !CHECK_FLAG(srp->flags, EXT_SUBTLV_PREFIX_SID_NPFLG))
                        continue;

                /* Process only SID Index */
                if (CHECK_FLAG(srp->flags, EXT_SUBTLV_PREFIX_SID_VFLG))
                        continue;

                /* First, remove old MPLS table entries ... */
                ospf_zebra_delete_prefix_sid(srp);
                /* ... then compute new input label ... */
                srp->label_in = index2label(srp->sid, OspfSR.self->srgb);
                /* ... and install new MPLS LFIB */
                ospf_zebra_update_prefix_sid(srp);
        }
}

/*
 * When SRGB has changed, update NHLFE Output Label for all Extended Prefix
 * with SID index which use the given SR-Node as nexthop through hash_iterate()
 */
static void update_out_nhlfe(struct hash_bucket *bucket, void *args)
{
        struct listnode *node, *pnode;
        struct sr_node *srn = (struct sr_node *)bucket->data;
        struct sr_node *srnext = (struct sr_node *)args;
        struct sr_prefix *srp;
        struct ospf_path *path;

        /* Skip Self SR-Node */
        if (srn == OspfSR.self)
                return;

        osr_debug("SR (%s): Update Out NHLFE for neighbor SR-Node %pI4",
                  __func__, &srn->adv_router);

        for (ALL_LIST_ELEMENTS_RO(srn->ext_prefix, node, srp)) {
                /* Skip Prefix that has not yet a valid route */
                if (srp->route == NULL)
                        continue;

                for (ALL_LIST_ELEMENTS_RO(srp->route->paths, pnode, path)) {
                        /* Skip path that has not next SR-Node as nexthop */
                        if (path->srni.nexthop != srnext)
                                continue;

                        /* Compute new Output Label */
                        path->srni.label_out = sr_prefix_out_label(srp, srnext);
                }

                /* Finally update MPLS table */
                ospf_zebra_update_prefix_sid(srp);
        }
}

/*
 * Following functions are call when new Segment Routing LSA are received
 *  - Router Information: ospf_sr_ri_lsa_update() & ospf_sr_ri_lsa_delete()
 *  - Extended Link: ospf_sr_ext_link_update() & ospf_sr_ext_link_delete()
 *  - Extended Prefix: ospf_ext_prefix_update() & ospf_sr_ext_prefix_delete()
 */

/* Update Segment Routing from Router Information LSA */
void ospf_sr_ri_lsa_update(struct ospf_lsa *lsa)
{
        struct sr_node *srn;
        struct tlv_header *tlvh;
        struct lsa_header *lsah = lsa->data;
        struct ri_sr_tlv_sid_label_range *ri_srgb = NULL;
        struct ri_sr_tlv_sid_label_range *ri_srlb = NULL;
        struct ri_sr_tlv_sr_algorithm *algo = NULL;
        struct sr_block srgb;
        uint16_t length = 0, sum = 0;
        uint8_t msd = 0;

        osr_debug("SR (%s): Process Router Information LSA 4.0.0.%u from %pI4",
                  __func__, GET_OPAQUE_ID(ntohl(lsah->id.s_addr)),
                  &lsah->adv_router);

        /* Sanity check */
        if (IS_LSA_SELF(lsa))
                return;

        if (OspfSR.neighbors == NULL) {
                flog_err(EC_OSPF_SR_INVALID_DB,
                         "SR (%s): Abort! no valid SR DataBase", __func__);
                return;
        }

        /* Search SR Node in hash table from Router ID */
        srn = (struct sr_node *)hash_lookup(OspfSR.neighbors,
                                            &lsah->adv_router);


        /* Collect Router Information Sub TLVs */
        /* Initialize TLV browsing */
        length = lsa->size - OSPF_LSA_HEADER_SIZE;
        srgb.range_size = 0;
        srgb.lower_bound = 0;

        for (tlvh = TLV_HDR_TOP(lsah); (sum < length) && (tlvh != NULL);
             tlvh = TLV_HDR_NEXT(tlvh)) {
                switch (ntohs(tlvh->type)) {
                case RI_SR_TLV_SR_ALGORITHM:
                        algo = (struct ri_sr_tlv_sr_algorithm *)tlvh;
                        break;
                case RI_SR_TLV_SRGB_LABEL_RANGE:
                        ri_srgb = (struct ri_sr_tlv_sid_label_range *)tlvh;
                        break;
                case RI_SR_TLV_SRLB_LABEL_RANGE:
                        ri_srlb = (struct ri_sr_tlv_sid_label_range *)tlvh;
                        break;
                case RI_SR_TLV_NODE_MSD:
                        msd = ((struct ri_sr_tlv_node_msd *)(tlvh))->value;
                        break;
                default:
                        break;
                }
                sum += TLV_SIZE(tlvh);
        }

        /* Check if Segment Routing Capabilities has been found */
        if (ri_srgb == NULL) {
                /* Skip Router Information without SR capabilities
                 * advertise by a non SR Node */
                if (srn == NULL) {
                        return;
                } else {
                        /* Remove SR Node that advertise Router Information
                         * without SR capabilities. This could correspond to a
                         * Node stopping Segment Routing */
                        hash_release(OspfSR.neighbors, &(srn->adv_router));
                        sr_node_del(srn);
                        return;
                }
        }

        /* Check that RI LSA belongs to the correct SR Node */
        if ((srn != NULL) && (srn->instance != 0)
            && (srn->instance != ntohl(lsah->id.s_addr))) {
                flog_err(EC_OSPF_SR_INVALID_LSA_ID,
                         "SR (%s): Abort! Wrong LSA ID 4.0.0.%u for SR node %pI4/%u",
                         __func__, GET_OPAQUE_ID(ntohl(lsah->id.s_addr)),
                         &lsah->adv_router, srn->instance);
                return;
        }

        /* OK. All things look good. Get SRGB */
        srgb.range_size = GET_RANGE_SIZE(ntohl(ri_srgb->size));
        srgb.lower_bound = GET_LABEL(ntohl(ri_srgb->lower.value));

        /* Check if it is a new SR Node or not */
        if (srn == NULL) {
                /* Get a new SR Node in hash table from Router ID */
                srn = (struct sr_node *)hash_get(OspfSR.neighbors,
                                                 &lsah->adv_router,
                                                 (void *)sr_node_new);
                /* Sanity check */
                if (srn == NULL) {
                        flog_err(
                                EC_OSPF_SR_NODE_CREATE,
                                "SR (%s): Abort! can't create SR node in hash table",
                                __func__);
                        return;
                }
                /* update LSA ID */
                srn->instance = ntohl(lsah->id.s_addr);
                /* Copy SRGB */
                srn->srgb.range_size = srgb.range_size;
                srn->srgb.lower_bound = srgb.lower_bound;
        }

        /* Update Algorithm, SRLB and MSD if present */
        if (algo != NULL) {
                int i;
                for (i = 0; i < ntohs(algo->header.length); i++)
                        srn->algo[i] = algo->value[0];
                for (; i < ALGORITHM_COUNT; i++)
                        srn->algo[i] = SR_ALGORITHM_UNSET;
        } else {
                srn->algo[0] = SR_ALGORITHM_SPF;
        }
        srn->msd = msd;
        if (ri_srlb != NULL) {
                srn->srlb.range_size = GET_RANGE_SIZE(ntohl(ri_srlb->size));
                srn->srlb.lower_bound = GET_LABEL(ntohl(ri_srlb->lower.value));
        }

        /* Check if SRGB has changed */
        if ((srn->srgb.range_size == srgb.range_size)
            && (srn->srgb.lower_bound == srgb.lower_bound))
                return;

        /* Copy SRGB */
        srn->srgb.range_size = srgb.range_size;
        srn->srgb.lower_bound = srgb.lower_bound;

        osr_debug("  |- Update SR-Node[%pI4], SRGB[%u/%u], SRLB[%u/%u], Algo[%u], MSD[%u]",
                  &srn->adv_router, srn->srgb.lower_bound, srn->srgb.range_size,
                  srn->srlb.lower_bound, srn->srlb.range_size, srn->algo[0],
                  srn->msd);

        /* ... and NHLFE if it is a neighbor SR node */
        if (srn->neighbor == OspfSR.self)
                hash_iterate(OspfSR.neighbors, update_out_nhlfe, srn);
}

/*
 * Delete SR Node entry in hash table information corresponding to an expired
 * Router Information LSA
 */
void ospf_sr_ri_lsa_delete(struct ospf_lsa *lsa)
{
        struct sr_node *srn;
        struct lsa_header *lsah = lsa->data;

        osr_debug("SR (%s): Remove SR node %pI4 from lsa_id 4.0.0.%u", __func__,
                  &lsah->adv_router, GET_OPAQUE_ID(ntohl(lsah->id.s_addr)));

        /* Sanity check */
        if (OspfSR.neighbors == NULL) {
                flog_err(EC_OSPF_SR_INVALID_DB,
                         "SR (%s): Abort! no valid SR Data Base", __func__);
                return;
        }

        /* Release Router ID entry in SRDB hash table */
        srn = hash_release(OspfSR.neighbors, &(lsah->adv_router));

        /* Sanity check */
        if (srn == NULL) {
                flog_err(EC_OSPF_SR_NODE_CREATE,
                         "SR (%s): Abort! no entry in SRDB for SR Node %pI4",
                         __func__, &lsah->adv_router);
                return;
        }

        if ((srn->instance != 0) && (srn->instance != ntohl(lsah->id.s_addr))) {
                flog_err(
                        EC_OSPF_SR_INVALID_LSA_ID,
                        "SR (%s): Abort! Wrong LSA ID 4.0.0.%u for SR node %pI4",
                        __func__, GET_OPAQUE_ID(ntohl(lsah->id.s_addr)),
                        &lsah->adv_router);
                return;
        }

        /* Remove SR node */
        sr_node_del(srn);
}

/* Update Segment Routing from Extended Link LSA */
void ospf_sr_ext_link_lsa_update(struct ospf_lsa *lsa)
{
        struct sr_node *srn;
        struct tlv_header *tlvh;
        struct lsa_header *lsah = lsa->data;
        struct sr_link *srl;

        int length;

        osr_debug("SR (%s): Process Extended Link LSA 8.0.0.%u from %pI4",
                  __func__, GET_OPAQUE_ID(ntohl(lsah->id.s_addr)),
                  &lsah->adv_router);

        /* Sanity check */
        if (OspfSR.neighbors == NULL) {
                flog_err(EC_OSPF_SR_INVALID_DB,
                         "SR (%s): Abort! no valid SR DataBase", __func__);
                return;
        }

        /* Get SR Node in hash table from Router ID */
        srn = (struct sr_node *)hash_get(OspfSR.neighbors,
                                         (void *)&(lsah->adv_router),
                                         (void *)sr_node_new);

        /* Sanity check */
        if (srn == NULL) {
                flog_err(EC_OSPF_SR_NODE_CREATE,
                         "SR (%s): Abort! can't create SR node in hash table",
                         __func__);
                return;
        }

        /* Initialize TLV browsing */
        length = lsa->size - OSPF_LSA_HEADER_SIZE;
        for (tlvh = TLV_HDR_TOP(lsah); length > 0 && tlvh;
             tlvh = TLV_HDR_NEXT(tlvh)) {
                if (ntohs(tlvh->type) == EXT_TLV_LINK) {
                        /* Got Extended Link information */
                        srl = get_ext_link_sid(tlvh, length);
                        /* Update SID if not null */
                        if (srl != NULL) {
                                srl->instance = ntohl(lsah->id.s_addr);
                                update_ext_link_sid(srn, srl, lsa->flags);
                        }
                }
                length -= TLV_SIZE(tlvh);
        }
}

/* Delete Segment Routing from Extended Link LSA */
void ospf_sr_ext_link_lsa_delete(struct ospf_lsa *lsa)
{
        struct listnode *node;
        struct sr_link *srl;
        struct sr_node *srn;
        struct lsa_header *lsah = lsa->data;
        uint32_t instance = ntohl(lsah->id.s_addr);

        osr_debug("SR (%s): Remove Extended Link LSA 8.0.0.%u from %pI4",
                  __func__, GET_OPAQUE_ID(ntohl(lsah->id.s_addr)),
                  &lsah->adv_router);

        /* Sanity check */
        if (OspfSR.neighbors == NULL) {
                flog_err(EC_OSPF_SR_INVALID_DB,
                         "SR (%s): Abort! no valid SR DataBase", __func__);
                return;
        }

        /* Search SR Node in hash table from Router ID */
        srn = (struct sr_node *)hash_lookup(OspfSR.neighbors,
                                            (void *)&(lsah->adv_router));

        /*
         * SR-Node may be NULL if it has been remove previously when
         * processing Router Information LSA deletion
         */
        if (srn == NULL) {
                flog_err(EC_OSPF_SR_INVALID_DB,
                         "SR (%s): Stop! no entry in SRDB for SR Node %pI4",
                         __func__, &lsah->adv_router);
                return;
        }

        /* Search for corresponding Segment Link */
        for (ALL_LIST_ELEMENTS_RO(srn->ext_link, node, srl))
                if (srl->instance == instance)
                        break;

        /* Remove Segment Link if found. Note that for Neighbors, only Global
         * Adj/Lan-Adj SID are stored in the SR-DB */
        if ((srl != NULL) && (srl->instance == instance)) {
                del_adj_sid(srl->nhlfe[0]);
                del_adj_sid(srl->nhlfe[1]);
                listnode_delete(srn->ext_link, srl);
                XFREE(MTYPE_OSPF_SR_PARAMS, srl);
        }
}

/* Add (LAN)Adjacency-SID from Extended Link Information */
void ospf_sr_ext_itf_add(struct ext_itf *exti)
{
        struct sr_node *srn = OspfSR.self;
        struct sr_link *srl;

        osr_debug("SR (%s): Add Extended Link LSA 8.0.0.%u from self", __func__,
                  exti->instance);

        /* Sanity check */
        if (srn == NULL)
                return;

        /* Initialize new Segment Routing Link */
        srl = XCALLOC(MTYPE_OSPF_SR_PARAMS, sizeof(struct sr_link));
        srl->srn = srn;
        srl->adv_router = srn->adv_router;
        srl->itf_addr = exti->link.link_data;
        srl->instance =
                SET_OPAQUE_LSID(OPAQUE_TYPE_EXTENDED_LINK_LSA, exti->instance);
        srl->remote_id = exti->link.link_id;
        switch (exti->stype) {
        case ADJ_SID:
                srl->type = ADJ_SID;
                /* Primary information */
                srl->flags[0] = exti->adj_sid[0].flags;
                if (CHECK_FLAG(exti->adj_sid[0].flags,
                               EXT_SUBTLV_LINK_ADJ_SID_VFLG))
                        srl->sid[0] = GET_LABEL(ntohl(exti->adj_sid[0].value));
                else
                        srl->sid[0] = ntohl(exti->adj_sid[0].value);
                if (exti->rmt_itf_addr.header.type == 0)
                        srl->nhlfe[0].nexthop = exti->link.link_id;
                else
                        srl->nhlfe[0].nexthop = exti->rmt_itf_addr.value;
                /* Backup Information if set */
                if (exti->adj_sid[1].header.type == 0)
                        break;
                srl->flags[1] = exti->adj_sid[1].flags;
                if (CHECK_FLAG(exti->adj_sid[1].flags,
                               EXT_SUBTLV_LINK_ADJ_SID_VFLG))
                        srl->sid[1] = GET_LABEL(ntohl(exti->adj_sid[1].value));
                else
                        srl->sid[1] = ntohl(exti->adj_sid[1].value);
                if (exti->rmt_itf_addr.header.type == 0)
                        srl->nhlfe[1].nexthop = exti->link.link_id;
                else
                        srl->nhlfe[1].nexthop = exti->rmt_itf_addr.value;
                break;
        case LAN_ADJ_SID:
                srl->type = LAN_ADJ_SID;
                /* Primary information */
                srl->flags[0] = exti->lan_sid[0].flags;
                if (CHECK_FLAG(exti->lan_sid[0].flags,
                               EXT_SUBTLV_LINK_ADJ_SID_VFLG))
                        srl->sid[0] = GET_LABEL(ntohl(exti->lan_sid[0].value));
                else
                        srl->sid[0] = ntohl(exti->lan_sid[0].value);
                if (exti->rmt_itf_addr.header.type == 0)
                        srl->nhlfe[0].nexthop = exti->lan_sid[0].neighbor_id;
                else
                        srl->nhlfe[0].nexthop = exti->rmt_itf_addr.value;
                /* Backup Information if set */
                if (exti->lan_sid[1].header.type == 0)
                        break;
                srl->flags[1] = exti->lan_sid[1].flags;
                if (CHECK_FLAG(exti->lan_sid[1].flags,
                               EXT_SUBTLV_LINK_ADJ_SID_VFLG))
                        srl->sid[1] = GET_LABEL(ntohl(exti->lan_sid[1].value));
                else
                        srl->sid[1] = ntohl(exti->lan_sid[1].value);
                if (exti->rmt_itf_addr.header.type == 0)
                        srl->nhlfe[1].nexthop = exti->lan_sid[1].neighbor_id;
                else
                        srl->nhlfe[1].nexthop = exti->rmt_itf_addr.value;
                break;
        case PREF_SID:
        case LOCAL_SID:
                /* Wrong SID Type. Abort! */
                XFREE(MTYPE_OSPF_SR_PARAMS, srl);
                return;
        }

        /* Segment Routing Link is ready, update it */
        update_ext_link_sid(srn, srl, OSPF_LSA_SELF);
}

/* Delete Prefix or (LAN)Adjacency-SID from Extended Link Information */
void ospf_sr_ext_itf_delete(struct ext_itf *exti)
{
        struct listnode *node;
        struct sr_node *srn = OspfSR.self;
        struct sr_prefix *srp = NULL;
        struct sr_link *srl = NULL;
        uint32_t instance;

        osr_debug("SR (%s): Remove Extended LSA %u.0.0.%u from self",
                  __func__, exti->stype == PREF_SID ? 7 : 8, exti->instance);

        /* Sanity check: SR-Node and Extended Prefix/Link list may have been
         * removed earlier when stopping OSPF or OSPF-SR */
        if (srn == NULL || srn->ext_prefix == NULL || srn->ext_link == NULL)
                return;

        if (exti->stype == PREF_SID) {
                instance = SET_OPAQUE_LSID(OPAQUE_TYPE_EXTENDED_PREFIX_LSA,
                                           exti->instance);
                for (ALL_LIST_ELEMENTS_RO(srn->ext_prefix, node, srp))
                        if (srp->instance == instance)
                                break;

                /* Uninstall Segment Prefix SID if found */
                if ((srp != NULL) && (srp->instance == instance))
                        ospf_zebra_delete_prefix_sid(srp);
        } else {
                /* Search for corresponding Segment Link for self SR-Node */
                instance = SET_OPAQUE_LSID(OPAQUE_TYPE_EXTENDED_LINK_LSA,
                                           exti->instance);
                for (ALL_LIST_ELEMENTS_RO(srn->ext_link, node, srl))
                        if (srl->instance == instance)
                                break;

                /* Remove Segment Link if found */
                if ((srl != NULL) && (srl->instance == instance)) {
                        del_adj_sid(srl->nhlfe[0]);
                        del_adj_sid(srl->nhlfe[1]);
                        listnode_delete(srn->ext_link, srl);
                        XFREE(MTYPE_OSPF_SR_PARAMS, srl);
                }
        }
}

/* Update Segment Routing from Extended Prefix LSA */
void ospf_sr_ext_prefix_lsa_update(struct ospf_lsa *lsa)
{
        struct sr_node *srn;
        struct tlv_header *tlvh;
        struct lsa_header *lsah = (struct lsa_header *)lsa->data;
        struct sr_prefix *srp;

        int length;

        osr_debug("SR (%s): Process Extended Prefix LSA 7.0.0.%u from %pI4",
                  __func__, GET_OPAQUE_ID(ntohl(lsah->id.s_addr)),
                  &lsah->adv_router);

        /* Sanity check */
        if (OspfSR.neighbors == NULL) {
                flog_err(EC_OSPF_SR_INVALID_DB,
                         "SR (%s): Abort! no valid SR DataBase", __func__);
                return;
        }

        /* Get SR Node in hash table from Router ID */
        srn = (struct sr_node *)hash_get(OspfSR.neighbors,
                                         (void *)&(lsah->adv_router),
                                         (void *)sr_node_new);

        /* Sanity check */
        if (srn == NULL) {
                flog_err(EC_OSPF_SR_NODE_CREATE,
                         "SR (%s): Abort! can't create SR node in hash table",
                         __func__);
                return;
        }

        /* Initialize TLV browsing */
        length = lsa->size - OSPF_LSA_HEADER_SIZE;
        for (tlvh = TLV_HDR_TOP(lsah); length > 0 && tlvh;
             tlvh = TLV_HDR_NEXT(tlvh)) {
                if (ntohs(tlvh->type) == EXT_TLV_LINK) {
                        /* Got Extended Link information */
                        srp = get_ext_prefix_sid(tlvh, length);
                        /* Update SID if not null */
                        if (srp != NULL) {
                                srp->instance = ntohl(lsah->id.s_addr);
                                update_ext_prefix_sid(srn, srp);
                        }
                }
                length -= TLV_SIZE(tlvh);
        }
}

/* Delete Segment Routing from Extended Prefix LSA */
void ospf_sr_ext_prefix_lsa_delete(struct ospf_lsa *lsa)
{
        struct listnode *node;
        struct sr_prefix *srp;
        struct sr_node *srn;
        struct lsa_header *lsah = (struct lsa_header *)lsa->data;
        uint32_t instance = ntohl(lsah->id.s_addr);

        osr_debug("SR (%s): Remove Extended Prefix LSA 7.0.0.%u from %pI4",
                  __func__, GET_OPAQUE_ID(ntohl(lsah->id.s_addr)),
                  &lsah->adv_router);

        /* Sanity check */
        if (OspfSR.neighbors == NULL) {
                flog_err(EC_OSPF_SR_INVALID_DB,
                         "SR (%s): Abort! no valid SR DataBase", __func__);
                return;
        }

        /* Search SR Node in hash table from Router ID */
        srn = (struct sr_node *)hash_lookup(OspfSR.neighbors,
                                            (void *)&(lsah->adv_router));

        /*
         * SR-Node may be NULL if it has been remove previously when
         * processing Router Information LSA deletion
         */
        if (srn == NULL) {
                flog_err(EC_OSPF_SR_INVALID_DB,
                         "SR (%s):  Stop! no entry in SRDB for SR Node %pI4",
                         __func__, &lsah->adv_router);
                return;
        }

        /* Search for corresponding Segment Prefix */
        for (ALL_LIST_ELEMENTS_RO(srn->ext_prefix, node, srp))
                if (srp->instance == instance)
                        break;

        /* Remove Prefix if found */
        if ((srp != NULL) && (srp->instance == instance)) {
                ospf_zebra_delete_prefix_sid(srp);
                listnode_delete(srn->ext_prefix, srp);
                XFREE(MTYPE_OSPF_SR_PARAMS, srp);
        } else {
                flog_err(
                        EC_OSPF_SR_INVALID_DB,
                        "SR (%s): Didn't found corresponding SR Prefix 7.0.0.%u for SR Node %pI4",
                        __func__, GET_OPAQUE_ID(ntohl(lsah->id.s_addr)),
                        &lsah->adv_router);
        }
}

/*
 * Update Prefix SID. Call by ospf_ext_pref_ism_change to
 * complete initial CLI command at startup.
 *
 * @param ifp - Loopback interface
 * @param pref - Prefix address of this interface
 *
 * @return - void
 */
void ospf_sr_update_local_prefix(struct interface *ifp, struct prefix *p)
{
        struct listnode *node;
        struct sr_prefix *srp;

        /* Sanity Check */
        if ((ifp == NULL) || (p == NULL))
                return;

        /*
         * Search if there is a Segment Prefix that correspond to this
         * interface or prefix, and update it if found
         */
        for (ALL_LIST_ELEMENTS_RO(OspfSR.self->ext_prefix, node, srp)) {
                if ((srp->nhlfe.ifindex == ifp->ifindex)
                    || ((IPV4_ADDR_SAME(&srp->prefv4.prefix, &p->u.prefix4))
                        && (srp->prefv4.prefixlen == p->prefixlen))) {

                        /* Update Interface & Prefix info */
                        srp->nhlfe.ifindex = ifp->ifindex;
                        IPV4_ADDR_COPY(&srp->prefv4.prefix, &p->u.prefix4);
                        srp->prefv4.prefixlen = p->prefixlen;
                        srp->prefv4.family = p->family;
                        IPV4_ADDR_COPY(&srp->nhlfe.nexthop, &p->u.prefix4);

                        /* OK. Let's Schedule Extended Prefix LSA */
                        srp->instance = ospf_ext_schedule_prefix_index(
                                ifp, srp->sid, &srp->prefv4, srp->flags);

                        osr_debug(
                                "  |-  Update Node SID %pFX - %u for self SR Node",
                                (struct prefix *)&srp->prefv4, srp->sid);

                        /* Install SID if NO-PHP is set and not EXPLICIT-NULL */
                        if (CHECK_FLAG(srp->flags, EXT_SUBTLV_PREFIX_SID_NPFLG)
                            && !CHECK_FLAG(srp->flags,
                                           EXT_SUBTLV_PREFIX_SID_EFLG)) {
                                srp->label_in = index2label(srp->sid,
                                                            OspfSR.self->srgb);
                                srp->nhlfe.label_out = MPLS_LABEL_IMPLICIT_NULL;
                                ospf_zebra_update_prefix_sid(srp);
                        }
                }
        }
}

/*
 * Following functions are used to update MPLS LFIB after a SPF run
 */

static void ospf_sr_nhlfe_update(struct hash_bucket *bucket, void *args)
{

        struct sr_node *srn = (struct sr_node *)bucket->data;
        struct listnode *node;
        struct sr_prefix *srp;
        bool old;
        int rc;

        osr_debug("  |-  Update Prefix for SR Node %pI4", &srn->adv_router);

        /* Skip Self SR Node */
        if (srn == OspfSR.self)
                return;

        /* Update Extended Prefix */
        for (ALL_LIST_ELEMENTS_RO(srn->ext_prefix, node, srp)) {

                /* Keep track of valid route */
                old = srp->route != NULL;

                /* Compute the new NHLFE */
                rc = compute_prefix_nhlfe(srp);

                /* Check computation result */
                switch (rc) {
                /* Routes are not know, remove old NHLFE if any to avoid loop */
                case -1:
                        if (old)
                                ospf_zebra_delete_prefix_sid(srp);
                        break;
                /* Routes exist but are not ready, skip it */
                case 0:
                        break;
                /* There is at least one route, update NHLFE */
                case 1:
                        ospf_zebra_update_prefix_sid(srp);
                        break;
                default:
                        break;
                }
        }
}

void ospf_sr_update_task(struct ospf *ospf)
{

        struct timeval start_time, stop_time;

        /* Check ospf and SR status */
        if ((ospf == NULL) || (OspfSR.status != SR_UP))
                return;

        monotime(&start_time);

        osr_debug("SR (%s): Start SPF update", __func__);

        hash_iterate(OspfSR.neighbors, (void (*)(struct hash_bucket *,
                                                 void *))ospf_sr_nhlfe_update,
                     NULL);

        monotime(&stop_time);

        osr_debug("SR (%s): SPF Processing Time(usecs): %lld", __func__,
                  (stop_time.tv_sec - start_time.tv_sec) * 1000000LL
                          + (stop_time.tv_usec - start_time.tv_usec));
}

/*
 * --------------------------------------
 * Following are vty command functions.
 * --------------------------------------
 */

/*
 * Segment Routing Router configuration
 *
 * Must be centralize as it concerns both Extended Link/Prefix LSA
 * and Router Information LSA. Choose to call it from Extended Prefix
 * write_config() call back.
 *
 * @param vty VTY output
 *
 * @return none
 */
void ospf_sr_config_write_router(struct vty *vty)
{
        struct listnode *node;
        struct sr_prefix *srp;
        uint32_t upper;

        if (OspfSR.status == SR_UP)
                vty_out(vty, " segment-routing on\n");

        upper = OspfSR.srgb.start + OspfSR.srgb.size - 1;
        if ((OspfSR.srgb.start != DEFAULT_SRGB_LABEL)
            || (OspfSR.srgb.size != DEFAULT_SRGB_SIZE))
                vty_out(vty, " segment-routing global-block %u %u",
                        OspfSR.srgb.start, upper);

        if ((OspfSR.srlb.start != DEFAULT_SRLB_LABEL) ||
            (OspfSR.srlb.end != DEFAULT_SRLB_END)) {
                if ((OspfSR.srgb.start == DEFAULT_SRGB_LABEL) &&
                    (OspfSR.srgb.size == DEFAULT_SRGB_SIZE))
                        vty_out(vty, " segment-routing global-block %u %u",
                                OspfSR.srgb.start, upper);
                vty_out(vty, " local-block %u %u\n", OspfSR.srlb.start,
                        OspfSR.srlb.end);
        } else
                vty_out(vty, "\n");

        if (OspfSR.msd != 0)
                vty_out(vty, " segment-routing node-msd %u\n", OspfSR.msd);

        if (OspfSR.self != NULL) {
                for (ALL_LIST_ELEMENTS_RO(OspfSR.self->ext_prefix, node, srp)) {
                        vty_out(vty, " segment-routing prefix %pFX index %u",
                                &srp->prefv4, srp->sid);
                        if (CHECK_FLAG(srp->flags, EXT_SUBTLV_PREFIX_SID_EFLG))
                                vty_out(vty, " explicit-null\n");
                        else if (CHECK_FLAG(srp->flags,
                                            EXT_SUBTLV_PREFIX_SID_NPFLG))
                                vty_out(vty, " no-php-flag\n");
                        else
                                vty_out(vty, "\n");
                }
        }
}

DEFUN(ospf_sr_enable,
       ospf_sr_enable_cmd,
       "segment-routing on",
       SR_STR
       "Enable Segment Routing\n")
{

        VTY_DECLVAR_INSTANCE_CONTEXT(ospf, ospf);

        if (OspfSR.status != SR_OFF)
                return CMD_SUCCESS;

        if (ospf->vrf_id != VRF_DEFAULT) {
                vty_out(vty,
                        "Segment Routing is only supported in default VRF\n");
                return CMD_WARNING_CONFIG_FAILED;
        }

        osr_debug("SR: Segment Routing: OFF -> ON");

        /* Start Segment Routing */
        OspfSR.status = SR_ON;
        ospf_sr_start(ospf);

        return CMD_SUCCESS;
}

DEFUN (no_ospf_sr_enable,
       no_ospf_sr_enable_cmd,
       "no segment-routing [on]",
       NO_STR
       SR_STR
       "Disable Segment Routing\n")
{

        if (OspfSR.status == SR_OFF)
                return CMD_SUCCESS;

        osr_debug("SR: Segment Routing: ON -> OFF");

        /* Start by Disabling Extended Link & Prefix LSA */
        ospf_ext_update_sr(false);

        /* then, disable Router Information SR parameters */
        ospf_router_info_update_sr(false, OspfSR.self);

        /* Finally, stop Segment Routing */
        ospf_sr_stop();

        return CMD_SUCCESS;
}

static int ospf_sr_enabled(struct vty *vty)
{
        if (OspfSR.status != SR_OFF)
                return 1;

        if (vty)
                vty_out(vty, "%% OSPF SR is not turned on\n");

        return 0;
}

/* tell if two ranges [r1_lower, r1_upper] and [r2_lower,r2_upper] overlap */
static bool ranges_overlap(uint32_t r1_lower, uint32_t r1_upper,
                           uint32_t r2_lower, uint32_t r2_upper)
{
        return !((r1_upper < r2_lower) || (r1_lower > r2_upper));
}


/* tell if a range is valid */
static bool sr_range_is_valid(uint32_t lower, uint32_t upper, uint32_t min_size)
{
        return (upper >= lower + min_size);
}

/**
 * Update SRGB and/or SRLB using new CLI values.
 *
 * @param gb_lower  Lower bound of the SRGB
 * @param gb_upper  Upper bound of the SRGB
 * @param lb_lower  Lower bound of the SRLB
 * @param lb_upper  Upper bound of the SRLB
 *
 * @return          0 on success, -1 otherwise
 */
static int update_sr_blocks(uint32_t gb_lower, uint32_t gb_upper,
                            uint32_t lb_lower, uint32_t lb_upper)
{

        /* Check if values have changed */
        bool gb_changed, lb_changed;
        uint32_t gb_size = gb_upper - gb_lower + 1;
        uint32_t lb_size = lb_upper - lb_lower + 1;

        gb_changed =
                (OspfSR.srgb.size != gb_size || OspfSR.srgb.start != gb_lower);
        lb_changed =
                (OspfSR.srlb.end != lb_upper || OspfSR.srlb.start != lb_lower);
        if (!gb_changed && !lb_changed)
                return 0;

        /* Check if SR is correctly started i.e. Label Manager connected */
        if (OspfSR.status != SR_UP) {
                OspfSR.srgb.size = gb_size;
                OspfSR.srgb.start = gb_lower;
                OspfSR.srlb.end = lb_upper;
                OspfSR.srlb.start = lb_lower;
                return 0;
        }

        /* Release old SRGB if it has changed and is active. */
        if (gb_changed) {

                sr_global_block_delete();

                /* Set new SRGB values - but do not reserve yet (we need to
                 * release the SRLB too) */
                OspfSR.srgb.size = gb_size;
                OspfSR.srgb.start = gb_lower;
                if (OspfSR.self != NULL) {
                        OspfSR.self->srgb.range_size = gb_size;
                        OspfSR.self->srgb.lower_bound = gb_lower;
                }
        }
        /* Release old SRLB if it has changed and reserve new block as needed.
         */
        if (lb_changed) {

                sr_local_block_delete();

                /* Set new SRLB values */
                if (sr_local_block_init(lb_lower, lb_upper) < 0) {
                        ospf_sr_stop();
                        return -1;
                }
                if (OspfSR.self != NULL) {
                        OspfSR.self->srlb.lower_bound = lb_lower;
                        OspfSR.self->srlb.range_size = lb_size;
                }
        }

        /*
         * Try to reserve the new SRGB from the Label Manger. If the
         * allocation fails, disable SR until new blocks are successfully
         * allocated.
         */
        if (gb_changed) {
                if (sr_global_block_init(OspfSR.srgb.start, OspfSR.srgb.size)
                    < 0) {
                        ospf_sr_stop();
                        return -1;
                }
        }

        /* Update Self SR-Node */
        if (OspfSR.self != NULL) {
                /* SRGB is reserved, set Router Information parameters */
                ospf_router_info_update_sr(true, OspfSR.self);

                /* and update NHLFE entries */
                if (gb_changed)
                        hash_iterate(OspfSR.neighbors,
                                     (void (*)(struct hash_bucket *,
                                               void *))update_in_nhlfe,
                                     NULL);

                /* and update (LAN)-Adjacency SID */
                if (lb_changed)
                        ospf_ext_link_srlb_update();
        }

        return 0;
}

DEFUN(sr_global_label_range, sr_global_label_range_cmd,
      "segment-routing global-block (16-1048575) (16-1048575) [local-block (16-1048575) (16-1048575)]",
      SR_STR
      "Segment Routing Global Block label range\n"
      "Lower-bound range in decimal (16-1048575)\n"
      "Upper-bound range in decimal (16-1048575)\n"
      "Segment Routing Local Block label range\n"
      "Lower-bound range in decimal (16-1048575)\n"
      "Upper-bound range in decimal (16-1048575)\n")
{
        uint32_t lb_upper, lb_lower;
        uint32_t gb_upper, gb_lower;
        int idx_gb_low = 2, idx_gb_up = 3;
        int idx_lb_low = 5, idx_lb_up = 6;

        /* Get lower and upper bound for mandatory global-block */
        gb_lower = strtoul(argv[idx_gb_low]->arg, NULL, 10);
        gb_upper = strtoul(argv[idx_gb_up]->arg, NULL, 10);

        /* SRLB values are taken from vtysh if there, else use the known ones */
        lb_upper = argc > idx_lb_up ? strtoul(argv[idx_lb_up]->arg, NULL, 10)
                                    : OspfSR.srlb.end;
        lb_lower = argc > idx_lb_low ? strtoul(argv[idx_lb_low]->arg, NULL, 10)
                                     : OspfSR.srlb.start;

        /* check correctness of input SRGB */
        if (!sr_range_is_valid(gb_lower, gb_upper, MIN_SRGB_SIZE)) {
                vty_out(vty, "Invalid SRGB range\n");
                return CMD_WARNING_CONFIG_FAILED;
        }

        /* check correctness of SRLB */
        if (!sr_range_is_valid(lb_lower, lb_upper, MIN_SRLB_SIZE)) {
                vty_out(vty, "Invalid SRLB range\n");
                return CMD_WARNING_CONFIG_FAILED;
        }

        /* Validate SRGB against SRLB */
        if (ranges_overlap(gb_lower, gb_upper, lb_lower, lb_upper)) {
                vty_out(vty,
                        "New SR Global Block (%u/%u) conflicts with Local Block (%u/%u)\n",
                        gb_lower, gb_upper, lb_lower, lb_upper);
                return CMD_WARNING_CONFIG_FAILED;
        }

        if (update_sr_blocks(gb_lower, gb_upper, lb_lower, lb_upper) < 0)
                return CMD_WARNING_CONFIG_FAILED;
        else
                return CMD_SUCCESS;
}

DEFUN(no_sr_global_label_range, no_sr_global_label_range_cmd,
      "no segment-routing global-block [(16-1048575) (16-1048575) local-block (16-1048575) (16-1048575)]",
      NO_STR SR_STR
      "Segment Routing Global Block label range\n"
      "Lower-bound range in decimal (16-1048575)\n"
      "Upper-bound range in decimal (16-1048575)\n"
      "Segment Routing Local Block label range\n"
      "Lower-bound range in decimal (16-1048575)\n"
      "Upper-bound range in decimal (16-1048575)\n")
{
        if (update_sr_blocks(DEFAULT_SRGB_LABEL, DEFAULT_SRGB_END,
                             DEFAULT_SRLB_LABEL, DEFAULT_SRLB_END)
            < 0)
                return CMD_WARNING_CONFIG_FAILED;
        else
                return CMD_SUCCESS;
}

#if CONFDATE > 20220528
CPP_NOTICE(
        "Use of the segment-routing local-block command is deprecated, use the combined global-block command instead")
#endif

DEFUN_HIDDEN(sr_local_label_range, sr_local_label_range_cmd,
             "segment-routing local-block (16-1048575) (16-1048575)",
             SR_STR
             "Segment Routing Local Block label range\n"
             "Lower-bound range in decimal (16-1048575)\n"
             "Upper-bound range in decimal (16-1048575)\n")
{
        uint32_t upper;
        uint32_t lower;
        uint32_t srgb_upper;
        int idx_low = 2;
        int idx_up = 3;

        /* Get lower and upper bound */
        lower = strtoul(argv[idx_low]->arg, NULL, 10);
        upper = strtoul(argv[idx_up]->arg, NULL, 10);

        /* check correctness of SRLB */
        if (!sr_range_is_valid(lower, upper, MIN_SRLB_SIZE)) {
                vty_out(vty, "Invalid SRLB range\n");
                return CMD_WARNING_CONFIG_FAILED;
        }

        /* Check if values have changed */
        if ((OspfSR.srlb.start == lower)
            && (OspfSR.srlb.end == upper))
                return CMD_SUCCESS;

        /* Validate SRLB against SRGB */
        srgb_upper = OspfSR.srgb.start + OspfSR.srgb.size - 1;

        if (ranges_overlap(OspfSR.srgb.start, srgb_upper, lower, upper)) {
                vty_out(vty,
                        "New SR Local Block (%u/%u) conflicts with Global Block (%u/%u)\n",
                        lower, upper, OspfSR.srgb.start, srgb_upper);
                return CMD_WARNING_CONFIG_FAILED;
        }

        if (update_sr_blocks(OspfSR.srgb.start, srgb_upper, lower, upper) < 0)
                return CMD_WARNING_CONFIG_FAILED;
        else
                return CMD_SUCCESS;
}

DEFUN_HIDDEN(no_sr_local_label_range, no_sr_local_label_range_cmd,
             "no segment-routing local-block [(16-1048575) (16-1048575)]",
             NO_STR SR_STR
             "Segment Routing Local Block label range\n"
             "Lower-bound range in decimal (16-1048575)\n"
             "Upper-bound range in decimal (16-1048575)\n")
{

        uint32_t srgb_end;

        /* Validate SRLB against SRGB */
        srgb_end = OspfSR.srgb.start + OspfSR.srgb.size - 1;
        if (ranges_overlap(OspfSR.srgb.start, srgb_end, DEFAULT_SRLB_LABEL,
                           DEFAULT_SRLB_END)) {
                vty_out(vty,
                        "New SR Local Block (%u/%u) conflicts with Global Block (%u/%u)\n",
                        DEFAULT_SRLB_LABEL, DEFAULT_SRLB_END, OspfSR.srgb.start,
                        srgb_end);
                return CMD_WARNING_CONFIG_FAILED;
        }

        if (update_sr_blocks(OspfSR.srgb.start, srgb_end, DEFAULT_SRLB_LABEL,
                             DEFAULT_SRLB_END)
            < 0)
                return CMD_WARNING_CONFIG_FAILED;
        else
                return CMD_SUCCESS;
}

DEFUN (sr_node_msd,
       sr_node_msd_cmd,
       "segment-routing node-msd (1-16)",
       SR_STR
       "Maximum Stack Depth for this router\n"
       "Maximum number of label that could be stack (1-16)\n")
{
        uint32_t msd;
        int idx = 1;

        if (!ospf_sr_enabled(vty))
                return CMD_WARNING_CONFIG_FAILED;

        /* Get MSD */
        argv_find(argv, argc, "(1-16)", &idx);
        msd = strtoul(argv[idx]->arg, NULL, 10);
        if (msd < 1 || msd > MPLS_MAX_LABELS) {
                vty_out(vty, "MSD must be comprise between 1 and %u\n",
                        MPLS_MAX_LABELS);
                return CMD_WARNING_CONFIG_FAILED;
        }

        /* Check if value has changed */
        if (OspfSR.msd == msd)
                return CMD_SUCCESS;

        /* Set this router MSD */
        OspfSR.msd = msd;
        if (OspfSR.self != NULL) {
                OspfSR.self->msd = msd;

                /* Set Router Information parameters if SR is UP */
                if (OspfSR.status == SR_UP)
                        ospf_router_info_update_sr(true, OspfSR.self);
        }

        return CMD_SUCCESS;
}

DEFUN (no_sr_node_msd,
        no_sr_node_msd_cmd,
        "no segment-routing node-msd [(1-16)]",
        NO_STR
        SR_STR
        "Maximum Stack Depth for this router\n"
        "Maximum number of label that could be stack (1-16)\n")
{

        if (!ospf_sr_enabled(vty))
                return CMD_WARNING_CONFIG_FAILED;

        /* unset this router MSD */
        OspfSR.msd = 0;
        if (OspfSR.self != NULL) {
                OspfSR.self->msd = 0;

                /* Set Router Information parameters if SR is UP */
                if (OspfSR.status == SR_UP)
                        ospf_router_info_update_sr(true, OspfSR.self);
        }

        return CMD_SUCCESS;
}

DEFUN (sr_prefix_sid,
       sr_prefix_sid_cmd,
       "segment-routing prefix A.B.C.D/M index (0-65535) [no-php-flag|explicit-null]",
       SR_STR
       "Prefix SID\n"
       "IPv4 Prefix as A.B.C.D/M\n"
       "SID index for this prefix in decimal (0-65535)\n"
       "Index value inside SRGB (lower_bound < index < upper_bound)\n"
       "Don't request Penultimate Hop Popping (PHP)\n"
       "Upstream neighbor must replace prefix-sid with explicit null label\n")
{
        int idx = 0;
        struct prefix p, pexist;
        uint32_t index;
        struct listnode *node;
        struct sr_prefix *srp, *exist = NULL;
        struct interface *ifp;
        bool no_php_flag = false;
        bool exp_null = false;
        bool index_in_use = false;
        uint8_t desired_flags = 0;

        if (!ospf_sr_enabled(vty))
                return CMD_WARNING_CONFIG_FAILED;

        /* Get network prefix */
        argv_find(argv, argc, "A.B.C.D/M", &idx);
        if (!str2prefix(argv[idx]->arg, &p)) {
                vty_out(vty, "Invalid prefix format %s\n", argv[idx]->arg);
                return CMD_WARNING_CONFIG_FAILED;
        }

        /* Get & verify index value */
        argv_find(argv, argc, "(0-65535)", &idx);
        index = strtoul(argv[idx]->arg, NULL, 10);
        if (index > OspfSR.srgb.size - 1) {
                vty_out(vty, "Index %u must be lower than range size %u\n",
                        index, OspfSR.srgb.size);
                return CMD_WARNING_CONFIG_FAILED;
        }

        /* Get options */
        no_php_flag = argv_find(argv, argc, "no-php-flag", &idx);
        exp_null = argv_find(argv, argc, "explicit-null", &idx);

        desired_flags |= no_php_flag ? EXT_SUBTLV_PREFIX_SID_NPFLG : 0;
        desired_flags |= exp_null ? EXT_SUBTLV_PREFIX_SID_NPFLG : 0;
        desired_flags |= exp_null ? EXT_SUBTLV_PREFIX_SID_EFLG : 0;

        /* Search for an existing Prefix-SID */
        for (ALL_LIST_ELEMENTS_RO(OspfSR.self->ext_prefix, node, srp)) {
                if (prefix_same((struct prefix *)&srp->prefv4, &p))
                        exist = srp;
                if (srp->sid == index) {
                        index_in_use = true;
                        pexist = p;
                }
        }

        /* done if prefix segment already there with same index and flags */
        if (exist && exist->sid == index && exist->flags == desired_flags)
                return CMD_SUCCESS;

        /* deny if index is already in use by a distinct prefix */
        if (!exist && index_in_use) {
                vty_out(vty, "Index %u is already used by %pFX\n", index,
                        &pexist);
                return CMD_WARNING_CONFIG_FAILED;
        }

        /* First, remove old NHLFE if installed */
        if (exist && CHECK_FLAG(exist->flags, EXT_SUBTLV_PREFIX_SID_NPFLG)
            && !CHECK_FLAG(exist->flags, EXT_SUBTLV_PREFIX_SID_EFLG))
                ospf_zebra_delete_prefix_sid(exist);

        /* Create new Extended Prefix to SRDB if not found */
        if (exist == NULL) {
                srp = XCALLOC(MTYPE_OSPF_SR_PARAMS, sizeof(struct sr_prefix));
                IPV4_ADDR_COPY(&srp->prefv4.prefix, &p.u.prefix4);
                srp->prefv4.prefixlen = p.prefixlen;
                srp->prefv4.family = p.family;
                srp->sid = index;
                srp->type = LOCAL_SID;
        } else {
                /* we work on the existing SR prefix */
                srp = exist;
        }

        /* Reset labels to handle flag update */
        srp->label_in = 0;
        srp->nhlfe.label_out = 0;
        srp->sid = index;
        srp->flags = desired_flags;

        /* If NO PHP flag is present, compute NHLFE and set label */
        if (no_php_flag) {
                srp->label_in = index2label(srp->sid, OspfSR.self->srgb);
                srp->nhlfe.label_out = MPLS_LABEL_IMPLICIT_NULL;
        }

        osr_debug("SR (%s): Add new index %u to Prefix %pFX", __func__, index,
                  (struct prefix *)&srp->prefv4);

        /* Get Interface and check if it is a Loopback */
        ifp = if_lookup_prefix(&p, VRF_DEFAULT);
        if (ifp == NULL) {
                /*
                 * Interface could be not yet available i.e. when this
                 * command is in the configuration file, OSPF is not yet
                 * ready. In this case, store the prefix SID for latter
                 * update of this Extended Prefix
                 */
                if (exist == NULL)
                        listnode_add(OspfSR.self->ext_prefix, srp);
                zlog_info(
                        "Interface for prefix %pFX not found. Deferred LSA flooding",
                        &p);
                return CMD_SUCCESS;
        }

        if (!if_is_loopback(ifp)) {
                vty_out(vty, "interface %s is not a Loopback\n", ifp->name);
                XFREE(MTYPE_OSPF_SR_PARAMS, srp);
                return CMD_WARNING_CONFIG_FAILED;
        }
        srp->nhlfe.ifindex = ifp->ifindex;

        /* Add SR Prefix if new */
        if (!exist)
                listnode_add(OspfSR.self->ext_prefix, srp);

        /* Update Prefix SID if SR is UP */
        if (OspfSR.status == SR_UP) {
                if (no_php_flag && !exp_null)
                        ospf_zebra_update_prefix_sid(srp);
        } else
                return CMD_SUCCESS;

        /* Finally, update Extended Prefix LSA id SR is UP */
        srp->instance = ospf_ext_schedule_prefix_index(
                ifp, srp->sid, &srp->prefv4, srp->flags);
        if (srp->instance == 0) {
                vty_out(vty, "Unable to set index %u for prefix %pFX\n",
                        index, &p);
                return CMD_WARNING;
        }

        return CMD_SUCCESS;
}

DEFUN (no_sr_prefix_sid,
       no_sr_prefix_sid_cmd,
       "no segment-routing prefix A.B.C.D/M [index (0-65535)|no-php-flag|explicit-null]",
       NO_STR
       SR_STR
       "Prefix SID\n"
       "IPv4 Prefix as A.B.C.D/M\n"
       "SID index for this prefix in decimal (0-65535)\n"
       "Index value inside SRGB (lower_bound < index < upper_bound)\n"
       "Don't request Penultimate Hop Popping (PHP)\n"
       "Upstream neighbor must replace prefix-sid with explicit null label\n")
{
        int idx = 0;
        struct prefix p;
        struct listnode *node;
        struct sr_prefix *srp;
        struct interface *ifp;
        bool found = false;
        int rc;

        if (!ospf_sr_enabled(vty))
                return CMD_WARNING_CONFIG_FAILED;

        if (OspfSR.status != SR_UP)
                return CMD_SUCCESS;

        /* Get network prefix */
        argv_find(argv, argc, "A.B.C.D/M", &idx);
        rc = str2prefix(argv[idx]->arg, &p);
        if (!rc) {
                vty_out(vty, "Invalid prefix format %s\n", argv[idx]->arg);
                return CMD_WARNING_CONFIG_FAILED;
        }

        /* check that the prefix is already set */
        for (ALL_LIST_ELEMENTS_RO(OspfSR.self->ext_prefix, node, srp))
                if (IPV4_ADDR_SAME(&srp->prefv4.prefix, &p.u.prefix4)
                    && (srp->prefv4.prefixlen == p.prefixlen)) {
                        found = true;
                        break;
                }

        if (!found) {
                vty_out(vty, "Prefix %s is not found. Abort!\n",
                        argv[idx]->arg);
                return CMD_WARNING_CONFIG_FAILED;
        }

        osr_debug("SR (%s): Remove Prefix %pFX with index %u", __func__,
                  (struct prefix *)&srp->prefv4, srp->sid);

        /* Get Interface */
        ifp = if_lookup_by_index(srp->nhlfe.ifindex, VRF_DEFAULT);
        if (ifp == NULL) {
                vty_out(vty, "interface for prefix %s not found.\n",
                        argv[idx]->arg);
                /* silently remove from list */
                listnode_delete(OspfSR.self->ext_prefix, srp);
                XFREE(MTYPE_OSPF_SR_PARAMS, srp);
                return CMD_SUCCESS;
        }

        /* Update Extended Prefix LSA */
        if (!ospf_ext_schedule_prefix_index(ifp, 0, NULL, 0)) {
                vty_out(vty, "No corresponding loopback interface. Abort!\n");
                return CMD_WARNING;
        }

        /* Delete NHLFE if NO-PHP is set and EXPLICIT NULL not set */
        if (CHECK_FLAG(srp->flags, EXT_SUBTLV_PREFIX_SID_NPFLG)
            && !CHECK_FLAG(srp->flags, EXT_SUBTLV_PREFIX_SID_EFLG))
                ospf_zebra_delete_prefix_sid(srp);

        /* OK, all is clean, remove SRP from SRDB */
        listnode_delete(OspfSR.self->ext_prefix, srp);
        XFREE(MTYPE_OSPF_SR_PARAMS, srp);

        return CMD_SUCCESS;
}


static char *sr_op2str(char *buf, size_t size, mpls_label_t label_in,
                       mpls_label_t label_out)
{
        if (size < 24)
                return NULL;

        switch (label_out) {
        case MPLS_LABEL_IMPLICIT_NULL:
                snprintf(buf, size, "Pop(%u)", label_in);
                break;
        case MPLS_LABEL_IPV4_EXPLICIT_NULL:
                if (label_in == MPLS_LABEL_IPV4_EXPLICIT_NULL)
                        snprintf(buf, size, "no-op.");
                else
                        snprintf(buf, size, "Swap(%u, null)", label_in);
                break;
        case MPLS_INVALID_LABEL:
                snprintf(buf, size, "no-op.");
                break;
        default:
                snprintf(buf, size, "Swap(%u, %u)", label_in, label_out);
                break;
        }
        return buf;
}

static void show_sr_prefix(struct sbuf *sbuf, struct json_object *json,
                           struct sr_prefix *srp)
{

        struct listnode *node;
        struct ospf_path *path;
        struct interface *itf;
        json_object *json_route = NULL, *json_obj;
        char pref[19];
        char sid[22];
        char op[32];
        char buf[PREFIX_STRLEN];
        int indent = 0;

        snprintfrr(pref, 19, "%pFX", (struct prefix *)&srp->prefv4);
        snprintf(sid, 22, "SR Pfx (idx %u)", srp->sid);
        if (json) {
                json_object_string_add(json, "prefix", pref);
                json_object_int_add(json, "sid", srp->sid);
                json_object_int_add(json, "inputLabel", srp->label_in);
        } else {
                sbuf_push(sbuf, 0, "%18s  %21s  ", pref, sid);
        }

        /* Check if it is a Local Node SID */
        if (srp->type == LOCAL_SID) {
                itf = if_lookup_by_index(srp->nhlfe.ifindex, VRF_DEFAULT);
                if (json) {
                        if (!json_route) {
                                json_route = json_object_new_array();
                                json_object_object_add(json, "prefixRoute",
                                                       json_route);
                        }
                        json_obj = json_object_new_object();
                        json_object_int_add(json_obj, "outputLabel",
                                            srp->nhlfe.label_out);
                        json_object_string_add(json_obj, "interface",
                                               itf ? itf->name : "-");
                        json_object_string_addf(json_obj, "nexthop", "%pI4",
                                                &srp->nhlfe.nexthop);
                        json_object_array_add(json_route, json_obj);
                } else {
                        sbuf_push(sbuf, 0, "%20s  %9s  %15s\n",
                                  sr_op2str(op, 32, srp->label_in,
                                            srp->nhlfe.label_out),
                                  itf ? itf->name : "-",
                                  inet_ntop(AF_INET, &srp->nhlfe.nexthop,
                                            buf, sizeof(buf)));
                }
                return;
        }

        /* Check if we have a valid path for this prefix */
        if (srp->route == NULL) {
                if (!json) {
                        sbuf_push(sbuf, 0, "\n");
                }
                return;
        }

        /* Process list of OSPF paths */
        for (ALL_LIST_ELEMENTS_RO(srp->route->paths, node, path)) {
                itf = if_lookup_by_index(path->ifindex, VRF_DEFAULT);
                if (json) {
                        if (!json_route) {
                                json_route = json_object_new_array();
                                json_object_object_add(json, "prefixRoute",
                                                       json_route);
                        }
                        json_obj = json_object_new_object();
                        json_object_int_add(json_obj, "outputLabel",
                                            path->srni.label_out);
                        json_object_string_add(json_obj, "interface",
                                               itf ? itf->name : "-");
                        json_object_string_addf(json_obj, "nexthop", "%pI4",
                                                &path->nexthop);
                        json_object_array_add(json_route, json_obj);
                } else {
                        sbuf_push(sbuf, indent, "%20s  %9s  %15s\n",
                                  sr_op2str(op, 32, srp->label_in,
                                            path->srni.label_out),
                                  itf ? itf->name : "-",
                                  inet_ntop(AF_INET, &path->nexthop, buf,
                                            sizeof(buf)));
                        /* Offset to align information for ECMP */
                        indent = 43;
                }
        }
}

static void show_sr_node(struct vty *vty, struct json_object *json,
                         struct sr_node *srn)
{

        struct listnode *node;
        struct sr_link *srl;
        struct sr_prefix *srp;
        struct interface *itf;
        struct sbuf sbuf;
        char pref[19];
        char sid[22];
        char op[32];
        char buf[PREFIX_STRLEN];
        uint32_t upper;
        json_object *json_node = NULL, *json_algo, *json_obj;
        json_object *json_prefix = NULL, *json_link = NULL;

        /* Sanity Check */
        if (srn == NULL)
                return;

        sbuf_init(&sbuf, NULL, 0);

        if (json) {
                json_node = json_object_new_object();
                json_object_string_addf(json_node, "routerID", "%pI4",
                                        &srn->adv_router);
                json_object_int_add(json_node, "srgbSize",
                                    srn->srgb.range_size);
                json_object_int_add(json_node, "srgbLabel",
                                    srn->srgb.lower_bound);
                json_object_int_add(json_node, "srlbSize",
                                    srn->srlb.range_size);
                json_object_int_add(json_node, "srlbLabel",
                                    srn->srlb.lower_bound);
                json_algo = json_object_new_array();
                json_object_object_add(json_node, "algorithms", json_algo);
                for (int i = 0; i < ALGORITHM_COUNT; i++) {
                        if (srn->algo[i] == SR_ALGORITHM_UNSET)
                                continue;
                        json_obj = json_object_new_object();
                        char tmp[2];

                        snprintf(tmp, sizeof(tmp), "%u", i);
                        json_object_string_add(json_obj, tmp,
                                               srn->algo[i] == SR_ALGORITHM_SPF
                                                       ? "SPF"
                                                       : "S-SPF");
                        json_object_array_add(json_algo, json_obj);
                }
                if (srn->msd != 0)
                        json_object_int_add(json_node, "nodeMsd", srn->msd);
        } else {
                sbuf_push(&sbuf, 0, "SR-Node: %pI4", &srn->adv_router);
                upper = srn->srgb.lower_bound + srn->srgb.range_size - 1;
                sbuf_push(&sbuf, 0, "\tSRGB: [%u/%u]",
                          srn->srgb.lower_bound, upper);
                upper = srn->srlb.lower_bound + srn->srlb.range_size - 1;
                sbuf_push(&sbuf, 0, "\tSRLB: [%u/%u]",
                          srn->srlb.lower_bound, upper);
                sbuf_push(&sbuf, 0, "\tAlgo.(s): %s",
                          srn->algo[0] == SR_ALGORITHM_SPF ? "SPF" : "S-SPF");
                for (int i = 1; i < ALGORITHM_COUNT; i++) {
                        if (srn->algo[i] == SR_ALGORITHM_UNSET)
                                continue;
                        sbuf_push(&sbuf, 0, "/%s",
                                  srn->algo[i] == SR_ALGORITHM_SPF ? "SPF"
                                                                   : "S-SPF");
                }
                if (srn->msd != 0)
                        sbuf_push(&sbuf, 0, "\tMSD: %u", srn->msd);
        }

        if (!json) {
                sbuf_push(&sbuf, 0,
                          "\n\n    Prefix or Link       Node or Adj. SID       Label Operation  Interface          Nexthop\n");
                sbuf_push(&sbuf, 0,
                          "------------------  ---------------------  --------------------  ---------  ---------------\n");
        }
        for (ALL_LIST_ELEMENTS_RO(srn->ext_prefix, node, srp)) {
                if (json) {
                        if (!json_prefix) {
                                json_prefix = json_object_new_array();
                                json_object_object_add(json_node,
                                                       "extendedPrefix",
                                                       json_prefix);
                        }
                        json_obj = json_object_new_object();
                        show_sr_prefix(NULL, json_obj, srp);
                        json_object_array_add(json_prefix, json_obj);
                } else {
                        show_sr_prefix(&sbuf, NULL, srp);
                }
        }

        for (ALL_LIST_ELEMENTS_RO(srn->ext_link, node, srl)) {
                snprintfrr(pref, 19, "%pI4/32", &srl->itf_addr);
                snprintf(sid, 22, "SR Adj. (lbl %u)", srl->sid[0]);
                itf = if_lookup_by_index(srl->nhlfe[0].ifindex, VRF_DEFAULT);
                if (json) {
                        if (!json_link) {
                                json_link = json_object_new_array();
                                json_object_object_add(
                                        json_node, "extendedLink", json_link);
                        }
                        /* Primary Link */
                        json_obj = json_object_new_object();
                        json_object_string_add(json_obj, "prefix", pref);
                        json_object_int_add(json_obj, "sid", srl->sid[0]);
                        json_object_int_add(json_obj, "inputLabel",
                                            srl->nhlfe[0].label_in);
                        json_object_int_add(json_obj, "outputLabel",
                                            srl->nhlfe[0].label_out);
                        json_object_string_add(json_obj, "interface",
                                               itf ? itf->name : "-");
                        json_object_string_addf(json_obj, "nexthop", "%pI4",
                                                &srl->nhlfe[0].nexthop);
                        json_object_array_add(json_link, json_obj);
                        /* Backup Link */
                        json_obj = json_object_new_object();
                        snprintf(sid, 22, "SR Adj. (lbl %u)", srl->sid[1]);
                        json_object_string_add(json_obj, "prefix", pref);
                        json_object_int_add(json_obj, "sid", srl->sid[1]);
                        json_object_int_add(json_obj, "inputLabel",
                                            srl->nhlfe[1].label_in);
                        json_object_int_add(json_obj, "outputLabel",
                                            srl->nhlfe[1].label_out);
                        json_object_string_add(json_obj, "interface",
                                               itf ? itf->name : "-");
                        json_object_string_addf(json_obj, "nexthop", "%pI4",
                                                &srl->nhlfe[1].nexthop);
                        json_object_array_add(json_link, json_obj);
                } else {
                        sbuf_push(&sbuf, 0, "%18s  %21s  %20s  %9s  %15s\n",
                                  pref, sid,
                                  sr_op2str(op, 32, srl->nhlfe[0].label_in,
                                            srl->nhlfe[0].label_out),
                                  itf ? itf->name : "-",
                                  inet_ntop(AF_INET, &srl->nhlfe[0].nexthop,
                                            buf, sizeof(buf)));
                        snprintf(sid, 22, "SR Adj. (lbl %u)", srl->sid[1]);
                        sbuf_push(&sbuf, 0, "%18s  %21s  %20s  %9s  %15s\n",
                                  pref, sid,
                                  sr_op2str(op, 32, srl->nhlfe[1].label_in,
                                            srl->nhlfe[1].label_out),
                                  itf ? itf->name : "-",
                                  inet_ntop(AF_INET, &srl->nhlfe[1].nexthop,
                                          buf, sizeof(buf)));
                }
        }
        if (json)
                json_object_array_add(json, json_node);
        else
                vty_out(vty, "%s\n", sbuf_buf(&sbuf));

        sbuf_free(&sbuf);
}

static void show_vty_srdb(struct hash_bucket *bucket, void *args)
{
        struct vty *vty = (struct vty *)args;
        struct sr_node *srn = (struct sr_node *)bucket->data;

        show_sr_node(vty, NULL, srn);
}

static void show_json_srdb(struct hash_bucket *bucket, void *args)
{
        struct json_object *json = (struct json_object *)args;
        struct sr_node *srn = (struct sr_node *)bucket->data;

        show_sr_node(NULL, json, srn);
}

DEFUN (show_ip_opsf_srdb,
       show_ip_ospf_srdb_cmd,
       "show ip ospf database segment-routing [adv-router A.B.C.D|self-originate] [json]",
       SHOW_STR
       IP_STR
       OSPF_STR
       "Database summary\n"
       "Show Segment Routing Data Base\n"
       "Advertising SR node\n"
       "Advertising SR node ID (as an IP address)\n"
       "Self-originated SR node\n"
       JSON_STR)
{
        int idx = 0;
        struct in_addr rid;
        struct sr_node *srn;
        bool uj = use_json(argc, argv);
        json_object *json = NULL, *json_node_array = NULL;

        if (OspfSR.status == SR_OFF) {
                vty_out(vty, "Segment Routing is disabled on this router\n");
                return CMD_WARNING;
        }

        if (uj) {
                json = json_object_new_object();
                json_node_array = json_object_new_array();
                json_object_string_addf(json, "srdbID", "%pI4",
                                        &OspfSR.self->adv_router);
                json_object_object_add(json, "srNodes", json_node_array);
        } else {
                vty_out(vty,
                        "\n\t\tOSPF Segment Routing database for ID %pI4\n\n",
                        &OspfSR.self->adv_router);
        }

        if (argv_find(argv, argc, "self-originate", &idx)) {
                srn = OspfSR.self;
                show_sr_node(vty, json_node_array, srn);
                if (uj)
                        vty_json(vty, json);
                return CMD_SUCCESS;
        }

        if (argv_find(argv, argc, "A.B.C.D", &idx)) {
                if (!inet_aton(argv[idx]->arg, &rid)) {
                        vty_out(vty, "Specified Router ID %s is invalid\n",
                                argv[idx]->arg);
                        return CMD_WARNING_CONFIG_FAILED;
                }
                /* Get the SR Node from the SRDB */
                srn = (struct sr_node *)hash_lookup(OspfSR.neighbors,
                                                    (void *)&rid);
                show_sr_node(vty, json_node_array, srn);
                if (uj)
                        vty_json(vty, json);
                return CMD_SUCCESS;
        }

        /* No parameters have been provided, Iterate through all the SRDB */
        if (uj) {
                hash_iterate(OspfSR.neighbors, (void (*)(struct hash_bucket *,
                                                         void *))show_json_srdb,
                             (void *)json_node_array);
                vty_json(vty, json);
        } else {
                hash_iterate(OspfSR.neighbors, (void (*)(struct hash_bucket *,
                                                         void *))show_vty_srdb,
                             (void *)vty);
        }
        return CMD_SUCCESS;
}

/* Install new CLI commands */
void ospf_sr_register_vty(void)
{
        install_element(VIEW_NODE, &show_ip_ospf_srdb_cmd);

        install_element(OSPF_NODE, &ospf_sr_enable_cmd);
        install_element(OSPF_NODE, &no_ospf_sr_enable_cmd);
        install_element(OSPF_NODE, &sr_global_label_range_cmd);
        install_element(OSPF_NODE, &no_sr_global_label_range_cmd);
        install_element(OSPF_NODE, &sr_local_label_range_cmd);
        install_element(OSPF_NODE, &no_sr_local_label_range_cmd);
        install_element(OSPF_NODE, &sr_node_msd_cmd);
        install_element(OSPF_NODE, &no_sr_node_msd_cmd);
        install_element(OSPF_NODE, &sr_prefix_sid_cmd);
        install_element(OSPF_NODE, &no_sr_prefix_sid_cmd);
}