Merge pull request #767 from donaldsharp/if_update

[mirror_frr.git] / zebra / zebra_mpls.c

/* Zebra MPLS code
 * Copyright (C) 2013 Cumulus Networks, Inc.
 *
 * This file is part of GNU Zebra.
 *
 * GNU Zebra is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2, or (at your option) any
 * later version.
 *
 * GNU Zebra is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; see the file COPYING; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <zebra.h>

#include "prefix.h"
#include "table.h"
#include "memory.h"
#include "command.h"
#include "if.h"
#include "log.h"
#include "sockunion.h"
#include "linklist.h"
#include "thread.h"
#include "workqueue.h"
#include "prefix.h"
#include "routemap.h"
#include "stream.h"
#include "nexthop.h"
#include "lib/json.h"

#include "zebra/rib.h"
#include "zebra/rt.h"
#include "zebra/zserv.h"
#include "zebra/redistribute.h"
#include "zebra/debug.h"
#include "zebra/zebra_memory.h"
#include "zebra/zebra_vrf.h"
#include "zebra/zebra_mpls.h"

DEFINE_MTYPE_STATIC(ZEBRA, LSP,			"MPLS LSP object")
DEFINE_MTYPE_STATIC(ZEBRA, FEC,			"MPLS FEC object")
DEFINE_MTYPE_STATIC(ZEBRA, SLSP,		"MPLS static LSP config")
DEFINE_MTYPE_STATIC(ZEBRA, NHLFE,		"MPLS nexthop object")
DEFINE_MTYPE_STATIC(ZEBRA, SNHLFE,		"MPLS static nexthop object")
DEFINE_MTYPE_STATIC(ZEBRA, SNHLFE_IFNAME,	"MPLS static nexthop ifname")

int mpls_enabled;

/* Default rtm_table for all clients */
extern struct zebra_t zebrad;

/* static function declarations */

static void
fec_evaluate (struct zebra_vrf *zvrf);
static u_int32_t
fec_derive_label_from_index (struct zebra_vrf *vrf, zebra_fec_t *fec);
static int
lsp_install (struct zebra_vrf *zvrf, mpls_label_t label,
             struct route_node *rn, struct route_entry *re);
static int
lsp_uninstall (struct zebra_vrf *zvrf, mpls_label_t label);
static int
fec_change_update_lsp (struct zebra_vrf *zvrf, zebra_fec_t *fec, mpls_label_t old_label);
static int
fec_send (zebra_fec_t *fec, struct zserv *client);
static void
fec_update_clients (zebra_fec_t *fec);
static void
fec_print (zebra_fec_t *fec, struct vty *vty);
static zebra_fec_t *
fec_find (struct route_table *table, struct prefix *p);
static zebra_fec_t *
fec_add (struct route_table *table, struct prefix *p, mpls_label_t label,
         u_int32_t flags, u_int32_t label_index);
static int
fec_del (zebra_fec_t *fec);

static unsigned int
label_hash (void *p);
static int
label_cmp (const void *p1, const void *p2);
static int
nhlfe_nexthop_active_ipv4 (zebra_nhlfe_t *nhlfe, struct nexthop *nexthop);
static int
nhlfe_nexthop_active_ipv6 (zebra_nhlfe_t *nhlfe, struct nexthop *nexthop);
static int
nhlfe_nexthop_active (zebra_nhlfe_t *nhlfe);

static void
lsp_select_best_nhlfe (zebra_lsp_t *lsp);
static void
lsp_uninstall_from_kernel (struct hash_backet *backet, void *ctxt);
static void
lsp_schedule (struct hash_backet *backet, void *ctxt);
static wq_item_status
lsp_process (struct work_queue *wq, void *data);
static void
lsp_processq_del (struct work_queue *wq, void *data);
static void
lsp_processq_complete (struct work_queue *wq);
static int
lsp_processq_add (zebra_lsp_t *lsp);
static void *
lsp_alloc (void *p);

static char *
nhlfe2str (zebra_nhlfe_t *nhlfe, char *buf, int size);
static int
nhlfe_nhop_match (zebra_nhlfe_t *nhlfe, enum nexthop_types_t gtype,
                  union g_addr *gate, ifindex_t ifindex);
static zebra_nhlfe_t *
nhlfe_find (zebra_lsp_t *lsp, enum lsp_types_t lsp_type,
            enum nexthop_types_t gtype, union g_addr *gate,
            ifindex_t ifindex);
static zebra_nhlfe_t *
nhlfe_add (zebra_lsp_t *lsp, enum lsp_types_t lsp_type,
           enum nexthop_types_t gtype, union g_addr *gate,
           ifindex_t ifindex, mpls_label_t out_label);
static int
nhlfe_del (zebra_nhlfe_t *snhlfe);
static void
nhlfe_out_label_update (zebra_nhlfe_t *nhlfe, struct nexthop_label *nh_label);
static int
mpls_lsp_uninstall_all (struct hash *lsp_table, zebra_lsp_t *lsp,
			enum lsp_types_t type);
static int
mpls_static_lsp_uninstall_all (struct zebra_vrf *zvrf, mpls_label_t in_label);
static void
nhlfe_print (zebra_nhlfe_t *nhlfe, struct vty *vty);
static void
lsp_print (zebra_lsp_t *lsp, void *ctxt);
static void *
slsp_alloc (void *p);
static int
snhlfe_match (zebra_snhlfe_t *snhlfe, enum nexthop_types_t gtype,
              union g_addr *gate, ifindex_t ifindex);
static zebra_snhlfe_t *
snhlfe_find (zebra_slsp_t *slsp, enum nexthop_types_t gtype,
             union g_addr *gate, ifindex_t ifindex);
static zebra_snhlfe_t *
snhlfe_add (zebra_slsp_t *slsp, enum nexthop_types_t gtype,
            union g_addr *gate, ifindex_t ifindex, mpls_label_t out_label);
static int
snhlfe_del (zebra_snhlfe_t *snhlfe);
static int
snhlfe_del_all (zebra_slsp_t *slsp);
static char *
snhlfe2str (zebra_snhlfe_t *snhlfe, char *buf, int size);
static int
mpls_processq_init (struct zebra_t *zebra);




/* Static functions */

/*
 * Install label forwarding entry based on labeled-route entry.
 */
static int
lsp_install (struct zebra_vrf *zvrf, mpls_label_t label,
             struct route_node *rn, struct route_entry *re)
{
  struct hash *lsp_table;
  zebra_ile_t tmp_ile;
  zebra_lsp_t *lsp;
  zebra_nhlfe_t *nhlfe;
  struct nexthop *nexthop;
  enum lsp_types_t  lsp_type;
  char buf[BUFSIZ];
  int added, changed;

  /* Lookup table. */
  lsp_table = zvrf->lsp_table;
  if (!lsp_table)
    return -1;

  lsp_type = lsp_type_from_re_type (re->type);
  added = changed = 0;

  /* Locate or allocate LSP entry. */
  tmp_ile.in_label = label;
  lsp = hash_get (lsp_table, &tmp_ile, lsp_alloc);
  if (!lsp)
    return -1;

  /* For each active nexthop, create NHLFE. Note that we deliberately skip
   * recursive nexthops right now, because intermediate hops won't understand
   * the label advertised by the recursive nexthop (plus we don't have the
   * logic yet to push multiple labels).
   */
  for (nexthop = re->nexthop; nexthop; nexthop = nexthop->next)
    {
      /* Skip inactive and recursive entries. */
      if (!CHECK_FLAG (nexthop->flags, NEXTHOP_FLAG_ACTIVE))
        continue;
      if (CHECK_FLAG(nexthop->flags, NEXTHOP_FLAG_RECURSIVE))
        continue;

      nhlfe = nhlfe_find (lsp, lsp_type, nexthop->type, &nexthop->gate,
                          nexthop->ifindex);
      if (nhlfe)
        {
          /* Clear deleted flag (in case it was set) */
          UNSET_FLAG (nhlfe->flags, NHLFE_FLAG_DELETED);
          if (nexthop_labels_match (nhlfe->nexthop, nexthop))
            /* No change */
            continue;


          if (IS_ZEBRA_DEBUG_MPLS)
            {
              nhlfe2str (nhlfe, buf, BUFSIZ);
              zlog_debug ("LSP in-label %u type %d nexthop %s "
                          "out-label changed",
                          lsp->ile.in_label, lsp_type, buf);
            }

          /* Update out label, trigger processing. */
          nhlfe_out_label_update (nhlfe, nexthop->nh_label);
          SET_FLAG (nhlfe->flags, NHLFE_FLAG_CHANGED);
          changed++;
        }
      else
        {
          /* Add LSP entry to this nexthop */
          nhlfe = nhlfe_add (lsp, lsp_type, nexthop->type,
                             &nexthop->gate, nexthop->ifindex,
                             nexthop->nh_label->label[0]);
          if (!nhlfe)
            return -1;

          if (IS_ZEBRA_DEBUG_MPLS)
            {
              nhlfe2str (nhlfe, buf, BUFSIZ);
              zlog_debug ("Add LSP in-label %u type %d nexthop %s "
                          "out-label %u",
                          lsp->ile.in_label, lsp_type, buf,
                          nexthop->nh_label->label[0]);
            }

          lsp->addr_family = NHLFE_FAMILY (nhlfe);

          /* Mark NHLFE as changed. */
          SET_FLAG(nhlfe->flags, NHLFE_FLAG_CHANGED);
          added++;
        }
    }

  /* Queue LSP for processing if necessary. If no NHLFE got added (special
   * case), delete the LSP entry; this case results in somewhat ugly logging.
   */
  if (added || changed)
    {
      if (lsp_processq_add (lsp))
        return -1;
    }
  else if (!lsp->nhlfe_list &&
           !CHECK_FLAG (lsp->flags, LSP_FLAG_SCHEDULED))
    {
      if (IS_ZEBRA_DEBUG_MPLS)
        zlog_debug ("Free LSP in-label %u flags 0x%x",
                    lsp->ile.in_label, lsp->flags);

      lsp = hash_release(lsp_table, &lsp->ile);
      if (lsp)
        XFREE(MTYPE_LSP, lsp);
    }

  return 0;
}

/*
 * Uninstall all non-static NHLFEs of a label forwarding entry. If all
 * NHLFEs are removed, the entire entry is deleted.
 */
static int
lsp_uninstall (struct zebra_vrf *zvrf, mpls_label_t label)
{
  struct hash *lsp_table;
  zebra_ile_t tmp_ile;
  zebra_lsp_t *lsp;
  zebra_nhlfe_t *nhlfe, *nhlfe_next;
  char buf[BUFSIZ];

  /* Lookup table. */
  lsp_table = zvrf->lsp_table;
  if (!lsp_table)
    return -1;

  /* If entry is not present, exit. */
  tmp_ile.in_label = label;
  lsp = hash_lookup (lsp_table, &tmp_ile);
  if (!lsp || !lsp->nhlfe_list)
    return 0;

  /* Mark NHLFEs for delete or directly delete, as appropriate. */
  for (nhlfe = lsp->nhlfe_list; nhlfe; nhlfe = nhlfe_next)
    {
      nhlfe_next = nhlfe->next;

      /* Skip static NHLFEs */
      if (nhlfe->type == ZEBRA_LSP_STATIC)
        continue;

      if (IS_ZEBRA_DEBUG_MPLS)
        {
          nhlfe2str (nhlfe, buf, BUFSIZ);
          zlog_debug ("Del LSP in-label %u type %d nexthop %s flags 0x%x",
                      label, nhlfe->type, buf, nhlfe->flags);
        }

      if (CHECK_FLAG(nhlfe->flags, NHLFE_FLAG_SELECTED))
        {
          UNSET_FLAG (nhlfe->flags, NHLFE_FLAG_CHANGED);
          SET_FLAG (nhlfe->flags, NHLFE_FLAG_DELETED);
        }
      else
        {
          nhlfe_del (nhlfe);
        }
    }

  /* Queue LSP for processing, if needed, else delete. */
  if (CHECK_FLAG(lsp->flags, LSP_FLAG_INSTALLED))
    {
      if (lsp_processq_add (lsp))
        return -1;
    }
  else if (!lsp->nhlfe_list &&
           !CHECK_FLAG (lsp->flags, LSP_FLAG_SCHEDULED))
    {
      if (IS_ZEBRA_DEBUG_MPLS)
        zlog_debug ("Del LSP in-label %u flags 0x%x",
                    lsp->ile.in_label, lsp->flags);

      lsp = hash_release(lsp_table, &lsp->ile);
      if (lsp)
        XFREE(MTYPE_LSP, lsp);
    }

  return 0;
}

/*
 * This function is invoked upon change to label block configuration; it
 * will walk all registered FECs with label-index and appropriately update
 * their local labels and trigger client updates.
 */
static void
fec_evaluate (struct zebra_vrf *zvrf)
{
  struct route_node *rn;
  zebra_fec_t *fec;
  u_int32_t old_label, new_label;
  int af;
  char buf[BUFSIZ];

  for (af = AFI_IP; af < AFI_MAX; af++)
    {
      if (zvrf->fec_table[af] == NULL)
        continue;

      for (rn = route_top(zvrf->fec_table[af]); rn; rn = route_next(rn))
        {
          if ((fec = rn->info) == NULL)
            continue;

          /* Skip configured FECs and those without a label index. */
          if (fec->flags & FEC_FLAG_CONFIGURED ||
              fec->label_index == MPLS_INVALID_LABEL_INDEX)
            continue;

          if (IS_ZEBRA_DEBUG_MPLS)
            prefix2str(&rn->p, buf, BUFSIZ);

          /* Save old label, determine new label. */
          old_label = fec->label;
          new_label = zvrf->mpls_srgb.start_label + fec->label_index;
          if (new_label >= zvrf->mpls_srgb.end_label)
            new_label = MPLS_INVALID_LABEL;

          /* If label has changed, update FEC and clients. */
          if (new_label == old_label)
            continue;

          if (IS_ZEBRA_DEBUG_MPLS)
            zlog_debug ("Update fec %s new label %u upon label block",
                         buf, new_label);

          fec->label = new_label;
          fec_update_clients (fec);

          /* Update label forwarding entries appropriately */
          fec_change_update_lsp (zvrf, fec, old_label);
        }
    }
}

/*
 * Derive (if possible) and update the local label for the FEC based on
 * its label index. The index is "acceptable" if it falls within the
 * globally configured label block (SRGB).
 */
static u_int32_t
fec_derive_label_from_index (struct zebra_vrf *zvrf, zebra_fec_t *fec)
{
  u_int32_t label;

  if (fec->label_index != MPLS_INVALID_LABEL_INDEX &&
      zvrf->mpls_srgb.start_label &&
      ((label = zvrf->mpls_srgb.start_label + fec->label_index) <
       zvrf->mpls_srgb.end_label))
    fec->label = label;
  else
    fec->label = MPLS_INVALID_LABEL;

  return fec->label;
}

/*
 * There is a change for this FEC. Install or uninstall label forwarding
 * entries, as appropriate.
 */
static int
fec_change_update_lsp (struct zebra_vrf *zvrf, zebra_fec_t *fec, mpls_label_t old_label)
{
  struct route_table *table;
  struct route_node *rn;
  struct route_entry *re;
  afi_t afi;

  /* Uninstall label forwarding entry, if previously installed. */
  if (old_label != MPLS_INVALID_LABEL &&
      old_label != MPLS_IMP_NULL_LABEL)
    lsp_uninstall (zvrf, old_label);

  /* Install label forwarding entry corr. to new label, if needed. */
  if (fec->label == MPLS_INVALID_LABEL ||
      fec->label == MPLS_IMP_NULL_LABEL)
    return 0;

  afi = family2afi(PREFIX_FAMILY(&fec->rn->p));
  table = zebra_vrf_table (afi, SAFI_UNICAST, zvrf_id (zvrf));
  if (!table)
    return 0;

  /* See if labeled route exists. */
  rn = route_node_lookup (table, &fec->rn->p);
  if (!rn)
    return 0;

  RNODE_FOREACH_RE (rn, re)
    {
      if (CHECK_FLAG (re->flags, ZEBRA_FLAG_SELECTED))
        break;
    }

  if (!re || !zebra_rib_labeled_unicast (re))
    return 0;

  if (lsp_install (zvrf, fec->label, rn, re))
    return -1;

  return 0;
}

/*
 * Inform about FEC to a registered client.
 */
static int
fec_send (zebra_fec_t *fec, struct zserv *client)
{
  struct stream *s;
  struct route_node *rn;

  rn = fec->rn;

  /* Get output stream. */
  s = client->obuf;
  stream_reset (s);

  zserv_create_header (s, ZEBRA_FEC_UPDATE, VRF_DEFAULT);

  stream_putw(s, rn->p.family);
  stream_put_prefix (s, &rn->p);
  stream_putl(s, fec->label);
  stream_putw_at(s, 0, stream_get_endp(s));
  return zebra_server_send_message(client);
}

/*
 * Update all registered clients about this FEC. Caller should've updated
 * FEC and ensure no duplicate updates.
 */
static void
fec_update_clients (zebra_fec_t *fec)
{
  struct listnode *node;
  struct zserv *client;

  for (ALL_LIST_ELEMENTS_RO(fec->client_list, node, client))
    {
      if (IS_ZEBRA_DEBUG_MPLS)
        zlog_debug ("Update client %s", zebra_route_string(client->proto));
      fec_send(fec, client);
    }
}


/*
 * Print a FEC-label binding entry.
 */
static void
fec_print (zebra_fec_t *fec, struct vty *vty)
{
  struct route_node *rn;
  struct listnode *node;
  struct zserv *client;
  char buf[BUFSIZ];

  rn = fec->rn;
  prefix2str(&rn->p, buf, BUFSIZ);
  vty_outln (vty, "%s", buf);
  vty_out(vty, "  Label: %s", label2str(fec->label, buf, BUFSIZ));
  if (fec->label_index != MPLS_INVALID_LABEL_INDEX)
    vty_out(vty, ", Label Index: %u", fec->label_index);
  vty_out (vty, VTYNL);
  if (!list_isempty(fec->client_list))
    {
      vty_out(vty, "  Client list:");
      for (ALL_LIST_ELEMENTS_RO(fec->client_list, node, client))
        vty_out(vty, " %s(fd %d)",
                zebra_route_string(client->proto), client->sock);
      vty_out (vty, VTYNL);
    }
}

/*
 * Locate FEC-label binding that matches with passed info.
 */
static zebra_fec_t *
fec_find (struct route_table *table, struct prefix *p)
{
  struct route_node *rn;

  apply_mask (p);
  rn = route_node_lookup(table, p);
  if (!rn)
    return NULL;

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

/*
 * Add a FEC. This may be upon a client registering for a binding
 * or when a binding is configured.
 */
static zebra_fec_t *
fec_add (struct route_table *table, struct prefix *p,
         mpls_label_t label, u_int32_t flags, u_int32_t label_index)
{
  struct route_node *rn;
  zebra_fec_t *fec;

  apply_mask (p);

  /* Lookup (or add) route node.*/
  rn = route_node_get (table, p);
  if (!rn)
    return NULL;

  fec = rn->info;

  if (!fec)
    {
      fec = XCALLOC (MTYPE_FEC, sizeof(zebra_fec_t));
      if (!fec)
        return NULL;

      rn->info = fec;
      fec->rn = rn;
      fec->label = label;
      fec->client_list = list_new();
    }
  else
    route_unlock_node (rn); /* for the route_node_get */

  fec->label_index = label_index;
  fec->flags = flags;

  return fec;
}

/*
 * Delete a FEC. This may be upon the last client deregistering for
 * a FEC and no binding exists or when the binding is deleted and there
 * are no registered clients.
 */
static int
fec_del (zebra_fec_t *fec)
{
  list_free (fec->client_list);
  fec->rn->info = NULL;
  route_unlock_node (fec->rn);
  XFREE (MTYPE_FEC, fec);
  return 0;
}

/*
 * Hash function for label.
 */
static unsigned int
label_hash (void *p)
{
  const zebra_ile_t *ile = p;

  return (jhash_1word(ile->in_label, 0));
}

/*
 * Compare 2 LSP hash entries based on in-label.
 */
static int
label_cmp (const void *p1, const void *p2)
{
  const zebra_ile_t *ile1 = p1;
  const zebra_ile_t *ile2 = p2;

  return (ile1->in_label == ile2->in_label);
}

/*
 * Check if an IPv4 nexthop for a NHLFE is active. Update nexthop based on
 * the passed flag.
 * NOTE: Looking only for connected routes right now.
 */
static int
nhlfe_nexthop_active_ipv4 (zebra_nhlfe_t *nhlfe, struct nexthop *nexthop)
{
  struct route_table *table;
  struct prefix_ipv4 p;
  struct route_node *rn;
  struct route_entry *match;
  struct nexthop *match_nh;

  table = zebra_vrf_table (AFI_IP, SAFI_UNICAST, VRF_DEFAULT);
  if (!table)
    return 0;

  /* Lookup nexthop in IPv4 routing table. */
  memset (&p, 0, sizeof (struct prefix_ipv4));
  p.family = AF_INET;
  p.prefixlen = IPV4_MAX_PREFIXLEN;
  p.prefix = nexthop->gate.ipv4;

  rn = route_node_match (table, (struct prefix *) &p);
  if (!rn)
    return 0;

  route_unlock_node (rn);

  /* Locate a valid connected route. */
  RNODE_FOREACH_RE (rn, match)
    {
      if (CHECK_FLAG (match->status, ROUTE_ENTRY_REMOVED) ||
	  !CHECK_FLAG (match->flags, ZEBRA_FLAG_SELECTED))
	continue;

      for (match_nh = match->nexthop; match_nh; match_nh = match_nh->next)
	{
	  if (match->type == ZEBRA_ROUTE_CONNECT ||
	      nexthop->ifindex == match_nh->ifindex)
	    {
	      nexthop->ifindex = match_nh->ifindex;
	      return 1;
	    }
	}
    }

  return 0;
}


/*
 * Check if an IPv6 nexthop for a NHLFE is active. Update nexthop based on
 * the passed flag.
 * NOTE: Looking only for connected routes right now.
 */
static int
nhlfe_nexthop_active_ipv6 (zebra_nhlfe_t *nhlfe, struct nexthop *nexthop)
{
  struct route_table *table;
  struct prefix_ipv6 p;
  struct route_node *rn;
  struct route_entry *match;

  table = zebra_vrf_table (AFI_IP6, SAFI_UNICAST, VRF_DEFAULT);
  if (!table)
    return 0;

  /* Lookup nexthop in IPv6 routing table. */
  memset (&p, 0, sizeof (struct prefix_ipv6));
  p.family = AF_INET6;
  p.prefixlen = IPV6_MAX_PREFIXLEN;
  p.prefix = nexthop->gate.ipv6;

  rn = route_node_match (table, (struct prefix *) &p);
  if (!rn)
    return 0;

  route_unlock_node (rn);

  /* Locate a valid connected route. */
  RNODE_FOREACH_RE (rn, match)
    {
      if ((match->type == ZEBRA_ROUTE_CONNECT) &&
          !CHECK_FLAG (match->status, ROUTE_ENTRY_REMOVED) &&
          CHECK_FLAG (match->flags, ZEBRA_FLAG_SELECTED))
        break;
    }

  if (!match || !match->nexthop)
    return 0;

  nexthop->ifindex = match->nexthop->ifindex;
  return 1;
}


/*
 * Check the nexthop reachability for a NHLFE and return if valid (reachable)
 * or not.
 * NOTE: Each NHLFE points to only 1 nexthop.
 */
static int
nhlfe_nexthop_active (zebra_nhlfe_t *nhlfe)
{
  struct nexthop *nexthop;
  struct interface *ifp;

  nexthop = nhlfe->nexthop;
  if (!nexthop) // unexpected
    return 0;

  /* Check on nexthop based on type. */
  switch (nexthop->type)
    {
      case NEXTHOP_TYPE_IPV4:
      case NEXTHOP_TYPE_IPV4_IFINDEX:
        if (nhlfe_nexthop_active_ipv4 (nhlfe, nexthop))
          SET_FLAG (nexthop->flags, NEXTHOP_FLAG_ACTIVE);
        else
          UNSET_FLAG (nexthop->flags, NEXTHOP_FLAG_ACTIVE);
        break;

      case NEXTHOP_TYPE_IPV6:
        if (nhlfe_nexthop_active_ipv6 (nhlfe, nexthop))
          SET_FLAG (nexthop->flags, NEXTHOP_FLAG_ACTIVE);
        else
          UNSET_FLAG (nexthop->flags, NEXTHOP_FLAG_ACTIVE);
        break;

      case NEXTHOP_TYPE_IPV6_IFINDEX:
        if (IN6_IS_ADDR_LINKLOCAL (&nexthop->gate.ipv6))
          {
            ifp = if_lookup_by_index (nexthop->ifindex, VRF_DEFAULT);
            if (ifp && if_is_operative(ifp))
              SET_FLAG (nexthop->flags, NEXTHOP_FLAG_ACTIVE);
            else
              UNSET_FLAG (nexthop->flags, NEXTHOP_FLAG_ACTIVE);
          }
        else
          {
            if (nhlfe_nexthop_active_ipv6 (nhlfe, nexthop))
              SET_FLAG (nexthop->flags, NEXTHOP_FLAG_ACTIVE);
            else
              UNSET_FLAG (nexthop->flags, NEXTHOP_FLAG_ACTIVE);
          }
        break;

    default:
      break;
    }

  return CHECK_FLAG (nexthop->flags, NEXTHOP_FLAG_ACTIVE);
}

/*
 * Walk through NHLFEs for a LSP forwarding entry, verify nexthop
 * reachability and select the best. Multipath entries are also
 * marked. This is invoked when an LSP scheduled for processing (due
 * to some change) is examined.
 */
static void
lsp_select_best_nhlfe (zebra_lsp_t *lsp)
{
  zebra_nhlfe_t *nhlfe;
  zebra_nhlfe_t *best;
  struct nexthop *nexthop;
  int changed = 0;

  if (!lsp)
    return;

  best = NULL;
  lsp->num_ecmp = 0;
  UNSET_FLAG (lsp->flags, LSP_FLAG_CHANGED);

  /*
   * First compute the best path, after checking nexthop status. We are only
   * concerned with non-deleted NHLFEs.
   */
  for (nhlfe = lsp->nhlfe_list; nhlfe; nhlfe = nhlfe->next)
    {
      /* Clear selection flags. */
      UNSET_FLAG (nhlfe->flags,
                  (NHLFE_FLAG_SELECTED | NHLFE_FLAG_MULTIPATH));

      if (!CHECK_FLAG (nhlfe->flags, NHLFE_FLAG_DELETED) &&
          nhlfe_nexthop_active (nhlfe))
        {
          if (!best || (nhlfe->distance < best->distance))
            best = nhlfe;
        }
    }

  lsp->best_nhlfe = best;
  if (!lsp->best_nhlfe)
    return;

  /* Mark best NHLFE as selected. */
  SET_FLAG (lsp->best_nhlfe->flags, NHLFE_FLAG_SELECTED);

  /*
   * If best path exists, see if there is ECMP. While doing this, note if a
   * new (uninstalled) NHLFE has been selected, an installed entry that is
   * still selected has a change or an installed entry is to be removed.
   */
  for (nhlfe = lsp->nhlfe_list; nhlfe; nhlfe = nhlfe->next)
    {
      int nh_chg, nh_sel, nh_inst;

      nexthop = nhlfe->nexthop;
      if (!nexthop) // unexpected
        continue;

      if (!CHECK_FLAG (nhlfe->flags, NHLFE_FLAG_DELETED) &&
          CHECK_FLAG (nexthop->flags, NEXTHOP_FLAG_ACTIVE) &&
          (nhlfe->distance == lsp->best_nhlfe->distance))
        {
          SET_FLAG (nhlfe->flags, NHLFE_FLAG_SELECTED);
          SET_FLAG (nhlfe->flags, NHLFE_FLAG_MULTIPATH);
          lsp->num_ecmp++;
        }

      if (CHECK_FLAG (lsp->flags, LSP_FLAG_INSTALLED) &&
          !changed)
        {
          nh_chg = CHECK_FLAG (nhlfe->flags, NHLFE_FLAG_CHANGED);
          nh_sel = CHECK_FLAG (nhlfe->flags, NHLFE_FLAG_SELECTED);
          nh_inst = CHECK_FLAG (nhlfe->flags, NHLFE_FLAG_INSTALLED);

          if ((nh_sel && !nh_inst) ||
              (nh_sel && nh_inst && nh_chg) ||
              (nh_inst && !nh_sel))
            changed = 1;
        }

      /* We have finished examining, clear changed flag. */
      UNSET_FLAG (nhlfe->flags, NHLFE_FLAG_CHANGED);
    }

  if (changed)
    SET_FLAG (lsp->flags, LSP_FLAG_CHANGED);
}

/*
 * Delete LSP forwarding entry from kernel, if installed. Called upon
 * process exit.
 */
static void
lsp_uninstall_from_kernel (struct hash_backet *backet, void *ctxt)
{
  zebra_lsp_t *lsp;

  lsp = (zebra_lsp_t *) backet->data;
  if (CHECK_FLAG(lsp->flags, LSP_FLAG_INSTALLED))
    kernel_del_lsp (lsp);
}

/*
 * Schedule LSP forwarding entry for processing. Called upon changes
 * that may impact LSPs such as nexthop / connected route changes.
 */
static void
lsp_schedule (struct hash_backet *backet, void *ctxt)
{
  zebra_lsp_t *lsp;

  lsp = (zebra_lsp_t *) backet->data;
  lsp_processq_add (lsp);
}

/*
 * Process a LSP entry that is in the queue. Recalculate best NHLFE and
 * any multipaths and update or delete from the kernel, as needed.
 */
static wq_item_status
lsp_process (struct work_queue *wq, void *data)
{
  zebra_lsp_t *lsp;
  zebra_nhlfe_t *oldbest, *newbest;
  char buf[BUFSIZ], buf2[BUFSIZ];
  struct zebra_vrf *zvrf = vrf_info_lookup (VRF_DEFAULT);

  lsp = (zebra_lsp_t *)data;
  if (!lsp) // unexpected
    return WQ_SUCCESS;

  oldbest = lsp->best_nhlfe;

  /* Select best NHLFE(s) */
  lsp_select_best_nhlfe (lsp);

  newbest = lsp->best_nhlfe;

  if (IS_ZEBRA_DEBUG_MPLS)
    {
      if (oldbest)
        nhlfe2str (oldbest, buf, BUFSIZ);
      if (newbest)
        nhlfe2str (newbest, buf2, BUFSIZ);
      zlog_debug ("Process LSP in-label %u oldbest %s newbest %s "
                  "flags 0x%x ecmp# %d",
                  lsp->ile.in_label, oldbest ? buf : "NULL",
                  newbest ? buf2 : "NULL", lsp->flags, lsp->num_ecmp);
    }

  if (!CHECK_FLAG (lsp->flags, LSP_FLAG_INSTALLED))
    {
      /* Not already installed */
      if (newbest)
        {
          kernel_add_lsp (lsp);
          zvrf->lsp_installs++;
        }
    }
  else
    {
      /* Installed, may need an update and/or delete. */
      if (!newbest)
        {
          kernel_del_lsp (lsp);
          zvrf->lsp_removals++;
        }
      else if (CHECK_FLAG (lsp->flags, LSP_FLAG_CHANGED))
        {
          kernel_upd_lsp (lsp);
          zvrf->lsp_installs++;
        }
    }

  return WQ_SUCCESS;
}


/*
 * Callback upon processing completion of a LSP forwarding entry.
 */
static void
lsp_processq_del (struct work_queue *wq, void *data)
{
  struct zebra_vrf *zvrf;
  zebra_lsp_t *lsp;
  struct hash *lsp_table;
  zebra_nhlfe_t *nhlfe, *nhlfe_next;

  zvrf = vrf_info_lookup(VRF_DEFAULT);
  assert (zvrf);

  lsp_table = zvrf->lsp_table;
  if (!lsp_table) // unexpected
    return;

  lsp = (zebra_lsp_t *)data;
  if (!lsp) // unexpected
    return;

  /* Clear flag, remove any NHLFEs marked for deletion. If no NHLFEs exist,
   * delete LSP entry also.
   */
  UNSET_FLAG (lsp->flags, LSP_FLAG_SCHEDULED);

  for (nhlfe = lsp->nhlfe_list; nhlfe; nhlfe = nhlfe_next)
    {
      nhlfe_next = nhlfe->next;
      if (CHECK_FLAG(nhlfe->flags, NHLFE_FLAG_DELETED))
        nhlfe_del (nhlfe);
    }

  if (!lsp->nhlfe_list)
    {
      if (IS_ZEBRA_DEBUG_MPLS)
        zlog_debug ("Free LSP in-label %u flags 0x%x",
                    lsp->ile.in_label, lsp->flags);

      lsp = hash_release(lsp_table, &lsp->ile);
      if (lsp)
        XFREE(MTYPE_LSP, lsp);
    }
}

/*
 * Callback upon finishing the processing of all scheduled
 * LSP forwarding entries.
 */
static void
lsp_processq_complete (struct work_queue *wq)
{
  /* Nothing to do for now. */
}

/*
 * Add LSP forwarding entry to queue for subsequent processing.
 */
static int
lsp_processq_add (zebra_lsp_t *lsp)
{
  /* If already scheduled, exit. */
  if (CHECK_FLAG (lsp->flags, LSP_FLAG_SCHEDULED))
    return 0;

  if (zebrad.lsp_process_q == NULL)
    {
      zlog_err ("%s: work_queue does not exist!", __func__);
      return -1;
    }

  work_queue_add (zebrad.lsp_process_q, lsp);
  SET_FLAG (lsp->flags, LSP_FLAG_SCHEDULED);
  return 0;
}

/*
 * Callback to allocate LSP forwarding table entry.
 */
static void *
lsp_alloc (void *p)
{
  const zebra_ile_t *ile = p;
  zebra_lsp_t *lsp;

  lsp = XCALLOC (MTYPE_LSP, sizeof(zebra_lsp_t));
  lsp->ile = *ile;

  if (IS_ZEBRA_DEBUG_MPLS)
    zlog_debug ("Alloc LSP in-label %u", lsp->ile.in_label);

  return ((void *)lsp);
}

/*
 * Create printable string for NHLFE entry.
 */
static char *
nhlfe2str (zebra_nhlfe_t *nhlfe, char *buf, int size)
{
  struct nexthop *nexthop;

  buf[0] = '\0';
  nexthop = nhlfe->nexthop;
  switch (nexthop->type)
    {
      case NEXTHOP_TYPE_IPV4:
      case NEXTHOP_TYPE_IPV4_IFINDEX:
        inet_ntop (AF_INET, &nexthop->gate.ipv4, buf, size);
        break;
      case NEXTHOP_TYPE_IPV6:
        inet_ntop (AF_INET6, &nexthop->gate.ipv6, buf, size);
        break;
      default:
        break;
    }

  return buf;
}

/*
 * Check if NHLFE matches with search info passed.
 */
static int
nhlfe_nhop_match (zebra_nhlfe_t *nhlfe, enum nexthop_types_t gtype,
                  union g_addr *gate, ifindex_t ifindex)
{
  struct nexthop *nhop;
  int cmp = 1;

  nhop = nhlfe->nexthop;
  if (!nhop)
    return 1;

  if (nhop->type != gtype)
    return 1;

  switch (nhop->type)
    {
    case NEXTHOP_TYPE_IPV4:
    case NEXTHOP_TYPE_IPV4_IFINDEX:
      cmp = memcmp(&(nhop->gate.ipv4), &(gate->ipv4),
                   sizeof(struct in_addr));
      if (!cmp && nhop->type == NEXTHOP_TYPE_IPV4_IFINDEX)
        cmp = !(nhop->ifindex == ifindex);
      break;
    case NEXTHOP_TYPE_IPV6:
    case NEXTHOP_TYPE_IPV6_IFINDEX:
      cmp = memcmp(&(nhop->gate.ipv6), &(gate->ipv6),
		   sizeof(struct in6_addr));
      if (!cmp && nhop->type == NEXTHOP_TYPE_IPV6_IFINDEX)
        cmp = !(nhop->ifindex == ifindex);
      break;
    default:
      break;
    }

  return cmp;
}


/*
 * Locate NHLFE that matches with passed info.
 */
static zebra_nhlfe_t *
nhlfe_find (zebra_lsp_t *lsp, enum lsp_types_t lsp_type,
            enum nexthop_types_t gtype, union g_addr *gate,
            ifindex_t ifindex)
{
  zebra_nhlfe_t *nhlfe;

  if (!lsp)
    return NULL;

  for (nhlfe = lsp->nhlfe_list; nhlfe; nhlfe = nhlfe->next)
    {
      if (nhlfe->type != lsp_type)
        continue;
      if (!nhlfe_nhop_match (nhlfe, gtype, gate, ifindex))
        break;
    }

  return nhlfe;
}

/*
 * Add NHLFE. Base entry must have been created and duplicate
 * check done.
 */
static zebra_nhlfe_t *
nhlfe_add (zebra_lsp_t *lsp, enum lsp_types_t lsp_type,
           enum nexthop_types_t gtype, union g_addr *gate,
           ifindex_t ifindex, mpls_label_t out_label)
{
  zebra_nhlfe_t *nhlfe;
  struct nexthop *nexthop;

  if (!lsp)
    return NULL;

  nhlfe = XCALLOC(MTYPE_NHLFE, sizeof(zebra_nhlfe_t));
  if (!nhlfe)
    return NULL;

  nhlfe->lsp = lsp;
  nhlfe->type = lsp_type;
  nhlfe->distance = lsp_distance (lsp_type);

  nexthop = nexthop_new();
  if (!nexthop)
    {
      XFREE (MTYPE_NHLFE, nhlfe);
      return NULL;
    }
  nexthop_add_labels (nexthop, lsp_type, 1, &out_label);

  nexthop->type = gtype;
  switch (nexthop->type)
    {
    case NEXTHOP_TYPE_IPV4:
    case NEXTHOP_TYPE_IPV4_IFINDEX:
      nexthop->gate.ipv4 = gate->ipv4;
      if (ifindex)
        nexthop->ifindex = ifindex;
      break;
    case NEXTHOP_TYPE_IPV6:
    case NEXTHOP_TYPE_IPV6_IFINDEX:
      nexthop->gate.ipv6 = gate->ipv6;
      if (ifindex)
        nexthop->ifindex = ifindex;
      break;
    default:
      nexthop_free(nexthop);
      XFREE (MTYPE_NHLFE, nhlfe);
      return NULL;
      break;
    }

  nhlfe->nexthop = nexthop;
  if (lsp->nhlfe_list)
    lsp->nhlfe_list->prev = nhlfe;
  nhlfe->next = lsp->nhlfe_list;
  lsp->nhlfe_list = nhlfe;

  return nhlfe;
}

/*
 * Delete NHLFE. Entry must be present on list.
 */
static int
nhlfe_del (zebra_nhlfe_t *nhlfe)
{
  zebra_lsp_t *lsp;

  if (!nhlfe)
    return -1;

  lsp = nhlfe->lsp;
  if (!lsp)
    return -1;

  /* Free nexthop. */
  if (nhlfe->nexthop)
    nexthop_free(nhlfe->nexthop);

  /* Unlink from LSP */
  if (nhlfe->next)
    nhlfe->next->prev = nhlfe->prev;
  if (nhlfe->prev)
    nhlfe->prev->next = nhlfe->next;
  else
    lsp->nhlfe_list = nhlfe->next;

  if (nhlfe == lsp->best_nhlfe)
    lsp->best_nhlfe = NULL;

  XFREE (MTYPE_NHLFE, nhlfe);

  return 0;
}

/*
 * Update label for NHLFE entry.
 */
static void
nhlfe_out_label_update (zebra_nhlfe_t *nhlfe, struct nexthop_label *nh_label)
{
  nhlfe->nexthop->nh_label->label[0] = nh_label->label[0];
}

static int
mpls_lsp_uninstall_all (struct hash *lsp_table, zebra_lsp_t *lsp,
			enum lsp_types_t type)
{
  zebra_nhlfe_t *nhlfe, *nhlfe_next;
  int schedule_lsp = 0;
  char buf[BUFSIZ];

  /* Mark NHLFEs for delete or directly delete, as appropriate. */
  for (nhlfe = lsp->nhlfe_list; nhlfe; nhlfe = nhlfe_next)
    {
      nhlfe_next = nhlfe->next;

      /* Skip non-static NHLFEs */
      if (nhlfe->type != type)
        continue;

      if (IS_ZEBRA_DEBUG_MPLS)
        {
          nhlfe2str (nhlfe, buf, BUFSIZ);
          zlog_debug ("Del LSP in-label %u type %d nexthop %s flags 0x%x",
                      lsp->ile.in_label, type, buf, nhlfe->flags);
        }

      if (CHECK_FLAG(nhlfe->flags, NHLFE_FLAG_INSTALLED))
        {
          UNSET_FLAG (nhlfe->flags, NHLFE_FLAG_CHANGED);
          SET_FLAG (nhlfe->flags, NHLFE_FLAG_DELETED);
          schedule_lsp = 1;
        }
      else
        {
          nhlfe_del (nhlfe);
        }
    }

  /* Queue LSP for processing, if needed, else delete. */
  if (schedule_lsp)
    {
      if (lsp_processq_add (lsp))
        return -1;
    }
  else if (!lsp->nhlfe_list &&
           !CHECK_FLAG (lsp->flags, LSP_FLAG_SCHEDULED))
    {
      if (IS_ZEBRA_DEBUG_MPLS)
        zlog_debug ("Free LSP in-label %u flags 0x%x",
                    lsp->ile.in_label, lsp->flags);

      lsp = hash_release(lsp_table, &lsp->ile);
      if (lsp)
        XFREE(MTYPE_LSP, lsp);
    }

  return 0;
}

/*
 * Uninstall all static NHLFEs for a particular LSP forwarding entry.
 * If no other NHLFEs exist, the entry would be deleted.
 */
static int
mpls_static_lsp_uninstall_all (struct zebra_vrf *zvrf, mpls_label_t in_label)
{
  struct hash *lsp_table;
  zebra_ile_t tmp_ile;
  zebra_lsp_t *lsp;

  /* Lookup table. */
  lsp_table = zvrf->lsp_table;
  if (!lsp_table)
    return -1;

  /* If entry is not present, exit. */
  tmp_ile.in_label = in_label;
  lsp = hash_lookup (lsp_table, &tmp_ile);
  if (!lsp || !lsp->nhlfe_list)
    return 0;

  return mpls_lsp_uninstall_all (lsp_table, lsp, ZEBRA_LSP_STATIC);
}

static json_object *
nhlfe_json (zebra_nhlfe_t *nhlfe)
{
  char buf[BUFSIZ];
  json_object *json_nhlfe = NULL;
  struct nexthop *nexthop = nhlfe->nexthop;

  json_nhlfe = json_object_new_object();
  json_object_string_add(json_nhlfe, "type", nhlfe_type2str(nhlfe->type));
  json_object_int_add(json_nhlfe, "outLabel", nexthop->nh_label->label[0]);
  json_object_int_add(json_nhlfe, "distance", nhlfe->distance);

  if (CHECK_FLAG (nhlfe->flags, NHLFE_FLAG_INSTALLED))
    json_object_boolean_true_add(json_nhlfe, "installed");

  switch (nexthop->type)
    {
    case NEXTHOP_TYPE_IPV4:
    case NEXTHOP_TYPE_IPV4_IFINDEX:
      json_object_string_add(json_nhlfe, "nexthop",
                             inet_ntoa (nexthop->gate.ipv4));
      break;
    case NEXTHOP_TYPE_IPV6:
    case NEXTHOP_TYPE_IPV6_IFINDEX:
      json_object_string_add(json_nhlfe, "nexthop",
                             inet_ntop (AF_INET6, &nexthop->gate.ipv6, buf, BUFSIZ));

      if (nexthop->ifindex)
        json_object_string_add(json_nhlfe, "interface", ifindex2ifname (nexthop->ifindex, VRF_DEFAULT));
      break;
    default:
      break;
    }
  return json_nhlfe;
}

/*
 * Print the NHLFE for a LSP forwarding entry.
 */
static void
nhlfe_print (zebra_nhlfe_t *nhlfe, struct vty *vty)
{
  struct nexthop *nexthop;
  char buf[BUFSIZ];

  nexthop = nhlfe->nexthop;
  if (!nexthop || !nexthop->nh_label) // unexpected
    return;

  vty_outln (vty, " type: %s remote label: %s distance: %d",
          nhlfe_type2str(nhlfe->type),
          label2str(nexthop->nh_label->label[0], buf, BUFSIZ),
          nhlfe->distance);
  switch (nexthop->type)
    {
    case NEXTHOP_TYPE_IPV4:
    case NEXTHOP_TYPE_IPV4_IFINDEX:
      vty_out (vty, "  via %s", inet_ntoa (nexthop->gate.ipv4));
      if (nexthop->ifindex)
        vty_out (vty, " dev %s", ifindex2ifname (nexthop->ifindex, VRF_DEFAULT));
      break;
    case NEXTHOP_TYPE_IPV6:
    case NEXTHOP_TYPE_IPV6_IFINDEX:
      vty_out (vty, "  via %s",
               inet_ntop (AF_INET6, &nexthop->gate.ipv6, buf, BUFSIZ));
      if (nexthop->ifindex)
        vty_out (vty, " dev %s", ifindex2ifname (nexthop->ifindex, VRF_DEFAULT));
      break;
    default:
      break;
    }
  vty_out(vty, "%s", CHECK_FLAG (nhlfe->flags, NHLFE_FLAG_INSTALLED) ?
          " (installed)" : "");
  vty_out (vty, VTYNL);
}

/*
 * Print an LSP forwarding entry.
 */
static void
lsp_print (zebra_lsp_t *lsp, void *ctxt)
{
  zebra_nhlfe_t *nhlfe;
  struct vty *vty;

  vty = (struct vty *) ctxt;

  vty_outln (vty, "Local label: %u%s",
          lsp->ile.in_label,
          CHECK_FLAG(lsp->flags, LSP_FLAG_INSTALLED) ? " (installed)" : "");

  for (nhlfe = lsp->nhlfe_list; nhlfe; nhlfe = nhlfe->next)
    nhlfe_print (nhlfe, vty);
}

/*
 * JSON objects for an LSP forwarding entry.
 */
static json_object *
lsp_json (zebra_lsp_t *lsp)
{
  zebra_nhlfe_t *nhlfe = NULL;
  json_object *json = json_object_new_object();
  json_object *json_nhlfe_list = json_object_new_array();

  json_object_int_add(json, "inLabel", lsp->ile.in_label);

  if (CHECK_FLAG (lsp->flags, LSP_FLAG_INSTALLED))
    json_object_boolean_true_add(json, "installed");

  for (nhlfe = lsp->nhlfe_list; nhlfe; nhlfe = nhlfe->next)
    json_object_array_add(json_nhlfe_list, nhlfe_json(nhlfe));

  json_object_object_add(json, "nexthops", json_nhlfe_list);
  return json;
}


/* Return a sorted linked list of the hash contents */
static struct list *
hash_get_sorted_list (struct hash *hash, void *cmp)
{
  unsigned int i;
  struct hash_backet *hb;
  struct list *sorted_list = list_new();

  sorted_list->cmp = (int (*)(void *, void *)) cmp;

  for (i = 0; i < hash->size; i++)
    for (hb = hash->index[i]; hb; hb = hb->next)
        listnode_add_sort(sorted_list, hb->data);

  return sorted_list;
}

/*
 * Compare two LSPs based on their label values.
 */
static int
lsp_cmp (zebra_lsp_t *lsp1, zebra_lsp_t *lsp2)
{
  if (lsp1->ile.in_label < lsp2->ile.in_label)
    return -1;

  if (lsp1->ile.in_label > lsp2->ile.in_label)
    return 1;

  return 0;
}

/*
 * Callback to allocate static LSP.
 */
static void *
slsp_alloc (void *p)
{
  const zebra_ile_t *ile = p;
  zebra_slsp_t *slsp;

  slsp = XCALLOC (MTYPE_SLSP, sizeof(zebra_slsp_t));
  slsp->ile = *ile;
  return ((void *)slsp);
}

/*
 * Compare two static LSPs based on their label values.
 */
static int
slsp_cmp (zebra_slsp_t *slsp1, zebra_slsp_t *slsp2)
{
  if (slsp1->ile.in_label < slsp2->ile.in_label)
    return -1;

  if (slsp1->ile.in_label > slsp2->ile.in_label)
    return 1;

  return 0;
}

/*
 * Check if static NHLFE matches with search info passed.
 */
static int
snhlfe_match (zebra_snhlfe_t *snhlfe, enum nexthop_types_t gtype,
              union g_addr *gate, ifindex_t ifindex)
{
  int cmp = 1;

  if (snhlfe->gtype != gtype)
    return 1;

  switch (snhlfe->gtype)
    {
    case NEXTHOP_TYPE_IPV4:
      cmp = memcmp(&(snhlfe->gate.ipv4), &(gate->ipv4),
		   sizeof(struct in_addr));
      break;
    case NEXTHOP_TYPE_IPV6:
    case NEXTHOP_TYPE_IPV6_IFINDEX:
      cmp = memcmp(&(snhlfe->gate.ipv6), &(gate->ipv6),
		   sizeof(struct in6_addr));
      if (!cmp && snhlfe->gtype == NEXTHOP_TYPE_IPV6_IFINDEX)
        cmp = !(snhlfe->ifindex == ifindex);
      break;
    default:
      break;
    }

  return cmp;
}

/*
 * Locate static NHLFE that matches with passed info.
 */
static zebra_snhlfe_t *
snhlfe_find (zebra_slsp_t *slsp, enum nexthop_types_t gtype,
             union g_addr *gate, ifindex_t ifindex)
{
  zebra_snhlfe_t *snhlfe;

  if (!slsp)
    return NULL;

  for (snhlfe = slsp->snhlfe_list; snhlfe; snhlfe = snhlfe->next)
    {
      if (!snhlfe_match (snhlfe, gtype, gate, ifindex))
        break;
    }

  return snhlfe;
}


/*
 * Add static NHLFE. Base LSP config entry must have been created
 * and duplicate check done.
 */
static zebra_snhlfe_t *
snhlfe_add (zebra_slsp_t *slsp, enum nexthop_types_t gtype,
            union g_addr *gate, ifindex_t ifindex,
            mpls_label_t out_label)
{
  zebra_snhlfe_t *snhlfe;

  if (!slsp)
    return NULL;

  snhlfe = XCALLOC(MTYPE_SNHLFE, sizeof(zebra_snhlfe_t));
  snhlfe->slsp = slsp;
  snhlfe->out_label = out_label;
  snhlfe->gtype = gtype;
  switch (gtype)
    {
    case NEXTHOP_TYPE_IPV4:
      snhlfe->gate.ipv4 = gate->ipv4;
      break;
    case NEXTHOP_TYPE_IPV6:
    case NEXTHOP_TYPE_IPV6_IFINDEX:
      snhlfe->gate.ipv6 = gate->ipv6;
      if (ifindex)
        snhlfe->ifindex = ifindex;
      break;
    default:
      XFREE (MTYPE_SNHLFE, snhlfe);
      return NULL;
    }

  if (slsp->snhlfe_list)
    slsp->snhlfe_list->prev = snhlfe;
  snhlfe->next = slsp->snhlfe_list;
  slsp->snhlfe_list = snhlfe;

  return snhlfe;
}

/*
 * Delete static NHLFE. Entry must be present on list.
 */
static int
snhlfe_del (zebra_snhlfe_t *snhlfe)
{
  zebra_slsp_t *slsp;

  if (!snhlfe)
    return -1;

  slsp = snhlfe->slsp;
  if (!slsp)
    return -1;

  if (snhlfe->next)
    snhlfe->next->prev = snhlfe->prev;
  if (snhlfe->prev)
    snhlfe->prev->next = snhlfe->next;
  else
    slsp->snhlfe_list = snhlfe->next;

  snhlfe->prev = snhlfe->next = NULL;
  if (snhlfe->ifname)
    XFREE (MTYPE_SNHLFE_IFNAME, snhlfe->ifname);
  XFREE (MTYPE_SNHLFE, snhlfe);

  return 0;
}

/*
 * Delete all static NHLFE entries for this LSP (in label).
 */
static int
snhlfe_del_all (zebra_slsp_t *slsp)
{
  zebra_snhlfe_t *snhlfe, *snhlfe_next;

  if (!slsp)
    return -1;

  for (snhlfe = slsp->snhlfe_list; snhlfe; snhlfe = snhlfe_next)
    {
      snhlfe_next = snhlfe->next;
      snhlfe_del (snhlfe);
    }

  return 0;
}

/*
 * Create printable string for NHLFE configuration.
 */
static char *
snhlfe2str (zebra_snhlfe_t *snhlfe, char *buf, int size)
{
  buf[0] = '\0';
  switch (snhlfe->gtype)
    {
      case NEXTHOP_TYPE_IPV4:
        inet_ntop (AF_INET, &snhlfe->gate.ipv4, buf, size);
        break;
      case NEXTHOP_TYPE_IPV6:
      case NEXTHOP_TYPE_IPV6_IFINDEX:
        inet_ntop (AF_INET6, &snhlfe->gate.ipv6, buf, size);
        if (snhlfe->ifindex)
          strcat (buf, ifindex2ifname (snhlfe->ifindex, VRF_DEFAULT));
        break;
      default:
        break;
    }

  return buf;
}

/*
 * Initialize work queue for processing changed LSPs.
 */
static int
mpls_processq_init (struct zebra_t *zebra)
{
  zebra->lsp_process_q = work_queue_new (zebra->master, "LSP processing");
  if (!zebra->lsp_process_q)
    {
      zlog_err ("%s: could not initialise work queue!", __func__);
      return -1;
    }

  zebra->lsp_process_q->spec.workfunc = &lsp_process;
  zebra->lsp_process_q->spec.del_item_data = &lsp_processq_del;
  zebra->lsp_process_q->spec.errorfunc = NULL;
  zebra->lsp_process_q->spec.completion_func = &lsp_processq_complete;
  zebra->lsp_process_q->spec.max_retries = 0;
  zebra->lsp_process_q->spec.hold = 10;

  return 0;
}



/* Public functions */

/*
 * String to label conversion, labels separated by '/'.
 *
 * @param label_str labels separated by /
 * @param num_labels number of labels; zero if conversion was unsuccessful
 * @param labels preallocated mpls_label_t array of size MPLS_MAX_LABELS; only
 *               modified if the conversion succeeded
 * @return  0 on success
 *         -1 if the string could not be parsed as integers
 *         -2 if a label was inside the reserved range (0-15)
 *         -3 if the number of labels given exceeds MPLS_MAX_LABELS
 */
int
mpls_str2label (const char *label_str, u_int8_t *num_labels,
                mpls_label_t *labels)
{
  char *ostr;                           // copy of label string (start)
  char *lstr;                           // copy of label string
  char *nump;                           // pointer to next segment
  char *endp;                           // end pointer
  int i;                                // for iterating label_str
  int rc;                               // return code
  mpls_label_t pl[MPLS_MAX_LABELS];     // parsed labels

  /* labels to zero until we have a successful parse */
  ostr = lstr = XSTRDUP (MTYPE_TMP, label_str);
  *num_labels = 0;
  rc = 0;

  for (i = 0; i < MPLS_MAX_LABELS && lstr && !rc; i++)
    {
      nump = strsep (&lstr, "/");
      pl[i] = strtoul(nump, &endp, 10);

      /* format check */
      if (*endp != '\0')
        rc = -1;
      /* validity check */
      else if (!IS_MPLS_UNRESERVED_LABEL(pl[i]))
        rc = -2;
    }

  /* excess labels */
  if (!rc && i == MPLS_MAX_LABELS && lstr)
    rc = -3;

  if (!rc)
    {
      *num_labels = i + 1;
      memcpy (labels, pl, *num_labels * sizeof (mpls_label_t));
    }

  XFREE (MTYPE_TMP, ostr);

  return rc;
}

/*
 * Label to string conversion, labels in string separated by '/'.
 */
char *
mpls_label2str (u_int8_t num_labels, mpls_label_t *labels,
                char *buf, int len, int pretty)
{
  char *buf_ptr = buf;
  buf[0] = '\0';

  if (pretty) {
    if (num_labels == 1) {
      label2str(labels[0], buf, len);
    } else if (num_labels == 2) {
      label2str(labels[0], buf, len);
      buf_ptr += strlen(buf);

      snprintf (buf_ptr, len, "/");
      buf_ptr++;

      label2str(labels[1], buf_ptr, len);
   }
  } else {
    if (num_labels == 1)
      snprintf (buf, len, "%u", labels[0]);
    else if (num_labels == 2)
      snprintf (buf, len, "%u/%u", labels[0], labels[1]);
  }
  return buf;
}

/*
 * Install dynamic LSP entry.
 */
int
zebra_mpls_lsp_install (struct zebra_vrf *zvrf, struct route_node *rn, struct route_entry *re)
{
  struct route_table *table;
  zebra_fec_t *fec;

  table = zvrf->fec_table[family2afi(PREFIX_FAMILY(&rn->p))];
  if (!table)
    return -1;

  /* See if there is a configured label binding for this FEC. */
  fec = fec_find (table, &rn->p);
  if (!fec || fec->label == MPLS_INVALID_LABEL)
    return 0;

  /* We cannot install a label forwarding entry if local label is the
   * implicit-null label.
   */
  if (fec->label == MPLS_IMP_NULL_LABEL)
    return 0;

  if (lsp_install (zvrf, fec->label, rn, re))
    return -1;

  return 0;
}

/*
 * Uninstall dynamic LSP entry, if any.
 */
int
zebra_mpls_lsp_uninstall (struct zebra_vrf *zvrf, struct route_node *rn, struct route_entry *re)
{
  struct route_table *table;
  zebra_fec_t *fec;

  table = zvrf->fec_table[family2afi(PREFIX_FAMILY(&rn->p))];
  if (!table)
    return -1;

  /* See if there is a configured label binding for this FEC. */
  fec = fec_find (table, &rn->p);
  if (!fec || fec->label == MPLS_INVALID_LABEL)
    return 0;

  /* Uninstall always removes all dynamic NHLFEs. */
  return lsp_uninstall (zvrf, fec->label);
}

/*
 * Registration from a client for the label binding for a FEC. If a binding
 * already exists, it is informed to the client.
 * NOTE: If there is a manually configured label binding, that is used.
 * Otherwise, if aa label index is specified, it means we have to allocate the
 * label from a locally configured label block (SRGB), if one exists and index
 * is acceptable.
 */
int
zebra_mpls_fec_register (struct zebra_vrf *zvrf, struct prefix *p,
                         u_int32_t label_index, struct zserv *client)
{
  struct route_table *table;
  zebra_fec_t *fec;
  char buf[BUFSIZ];
  int new_client;
  int label_change = 0;
  u_int32_t old_label;

  table = zvrf->fec_table[family2afi(PREFIX_FAMILY(p))];
  if (!table)
    return -1;

  if (IS_ZEBRA_DEBUG_MPLS)
    prefix2str(p, buf, BUFSIZ);

  /* Locate FEC */
  fec = fec_find (table, p);
  if (!fec)
    {
      fec = fec_add (table, p, MPLS_INVALID_LABEL, 0, label_index);
      if (!fec)
        {
          prefix2str(p, buf, BUFSIZ);
          zlog_err("Failed to add FEC %s upon register, client %s",
                   buf, zebra_route_string(client->proto));
          return -1;
        }

      old_label = MPLS_INVALID_LABEL;
      new_client = 1;
    }
  else
    {
      /* Client may register same FEC with different label index. */
      new_client = (listnode_lookup(fec->client_list, client) == NULL);
      if (!new_client && fec->label_index == label_index)
        /* Duplicate register */
        return 0;

      /* Save current label, update label index */
      old_label = fec->label;
      fec->label_index = label_index;
    }

  if (new_client)
    listnode_add (fec->client_list, client);

  if (IS_ZEBRA_DEBUG_MPLS)
    zlog_debug("FEC %s Label Index %u %s by client %s",
                buf, label_index, new_client ? "registered" : "updated",
                zebra_route_string(client->proto));

  /* If not a configured FEC, derive the local label (from label index)
   * or reset it.
   */
  if (!(fec->flags & FEC_FLAG_CONFIGURED))
    {
      fec_derive_label_from_index (zvrf, fec);

      /* If no label change, exit. */
      if (fec->label == old_label)
        return 0;

      label_change = 1;
    }

  /* If new client or label change, update client and install or uninstall
   * label forwarding entry as needed.
   */
  /* Inform client of label, if needed. */
  if ((new_client && fec->label != MPLS_INVALID_LABEL) ||
      label_change)
    {
      if (IS_ZEBRA_DEBUG_MPLS)
        zlog_debug ("Update client label %u", fec->label);
      fec_send (fec, client);
    }

  if (new_client || label_change)
    return fec_change_update_lsp (zvrf, fec, old_label);

  return 0;
}

/*
 * Deregistration from a client for the label binding for a FEC. The FEC
 * itself is deleted if no other registered clients exist and there is no
 * label bound to the FEC.
 */
int
zebra_mpls_fec_unregister (struct zebra_vrf *zvrf, struct prefix *p,
                           struct zserv *client)
{
  struct route_table *table;
  zebra_fec_t *fec;
  char buf[BUFSIZ];

  table = zvrf->fec_table[family2afi(PREFIX_FAMILY(p))];
  if (!table)
    return -1;

  if (IS_ZEBRA_DEBUG_MPLS)
    prefix2str(p, buf, BUFSIZ);

  fec = fec_find (table, p);
  if (!fec)
    {
      prefix2str(p, buf, BUFSIZ);
      zlog_err("Failed to find FEC %s upon unregister, client %s",
               buf, zebra_route_string(client->proto));
      return -1;
    }

  listnode_delete(fec->client_list, client);

  if (IS_ZEBRA_DEBUG_MPLS)
    zlog_debug("FEC %s unregistered by client %s",
                buf, zebra_route_string(client->proto));

  /* If not a configured entry, delete the FEC if no other clients. Before
   * deleting, see if any LSP needs to be uninstalled.
   */
  if (!(fec->flags & FEC_FLAG_CONFIGURED) &&
      list_isempty(fec->client_list))
    {
      mpls_label_t old_label = fec->label;
      fec->label = MPLS_INVALID_LABEL; /* reset */
      fec_change_update_lsp (zvrf, fec, old_label);
      fec_del (fec);
    }

  return 0;
}

/*
 * Cleanup any FECs registered by this client.
 */
int
zebra_mpls_cleanup_fecs_for_client (struct zebra_vrf *zvrf, struct zserv *client)
{
  struct route_node *rn;
  zebra_fec_t *fec;
  struct listnode *node;
  struct zserv *fec_client;
  int af;

  for (af = AFI_IP; af < AFI_MAX; af++)
    {
      if (zvrf->fec_table[af] == NULL)
        continue;

      for (rn = route_top(zvrf->fec_table[af]); rn; rn = route_next(rn))
        {
          fec = rn->info;
          if (!fec || list_isempty(fec->client_list))
            continue;

          for (ALL_LIST_ELEMENTS_RO(fec->client_list, node, fec_client))
            {
              if (fec_client == client)
                {
                  listnode_delete(fec->client_list, fec_client);
                  if (!(fec->flags & FEC_FLAG_CONFIGURED) &&
                      list_isempty(fec->client_list))
                    fec_del (fec);
                  break;
                }
            }
        }
    }

  return 0;
}

/*
 * Return FEC (if any) to which this label is bound.
 * Note: Only works for per-prefix binding and when the label is not
 * implicit-null.
 * TODO: Currently walks entire table, can optimize later with another
 * hash..
 */
zebra_fec_t *
zebra_mpls_fec_for_label (struct zebra_vrf *zvrf, mpls_label_t label)
{
  struct route_node *rn;
  zebra_fec_t *fec;
  int af;

  for (af = AFI_IP; af < AFI_MAX; af++)
    {
      if (zvrf->fec_table[af] == NULL)
        continue;

      for (rn = route_top(zvrf->fec_table[af]); rn; rn = route_next(rn))
        {
          if (!rn->info)
            continue;
          fec = rn->info;
          if (fec->label == label)
            return fec;
        }
    }

  return NULL;
}

/*
 * Inform if specified label is currently bound to a FEC or not.
 */
int
zebra_mpls_label_already_bound (struct zebra_vrf *zvrf, mpls_label_t label)
{
  return (zebra_mpls_fec_for_label (zvrf, label) ? 1 : 0);
}

/*
 * Add static FEC to label binding. If there are clients registered for this
 * FEC, notify them. If there are labeled routes for this FEC, install the
 * label forwarding entry.
*/
int
zebra_mpls_static_fec_add (struct zebra_vrf *zvrf, struct prefix *p,
                           mpls_label_t in_label)
{
  struct route_table *table;
  zebra_fec_t *fec;
  char buf[BUFSIZ];
  mpls_label_t old_label;
  int ret = 0;

  table = zvrf->fec_table[family2afi(PREFIX_FAMILY(p))];
  if (!table)
    return -1;

  if (IS_ZEBRA_DEBUG_MPLS)
    prefix2str(p, buf, BUFSIZ);

  /* Update existing FEC or create a new one. */
  fec = fec_find (table, p);
  if (!fec)
    {
      fec = fec_add (table, p, in_label, FEC_FLAG_CONFIGURED,
                     MPLS_INVALID_LABEL_INDEX);
      if (!fec)
        {
          prefix2str(p, buf, BUFSIZ);
          zlog_err ("Failed to add FEC %s upon config", buf);
          return -1;
        }

      if (IS_ZEBRA_DEBUG_MPLS)
        zlog_debug ("Add fec %s label %u", buf, in_label);
    }
  else
    {
      fec->flags |= FEC_FLAG_CONFIGURED;
      if (fec->label == in_label)
        /* Duplicate config */
        return 0;

      /* Label change, update clients. */
      old_label = fec->label;
      if (IS_ZEBRA_DEBUG_MPLS)
        zlog_debug ("Update fec %s new label %u", buf, in_label);

      fec->label = in_label;
      fec_update_clients (fec);

      /* Update label forwarding entries appropriately */
      ret = fec_change_update_lsp (zvrf, fec, old_label);
    }

  return ret;
}

/*
 * Remove static FEC to label binding. If there are no clients registered
 * for this FEC, delete the FEC; else notify clients
 * Note: Upon delete of static binding, if label index exists for this FEC,
 * client may need to be updated with derived label.
 */
int
zebra_mpls_static_fec_del (struct zebra_vrf *zvrf, struct prefix *p)
{
  struct route_table *table;
  zebra_fec_t *fec;
  mpls_label_t old_label;
  char buf[BUFSIZ];

  table = zvrf->fec_table[family2afi(PREFIX_FAMILY(p))];
  if (!table)
    return -1;

  fec = fec_find (table, p);
  if (!fec)
    {
      prefix2str(p, buf, BUFSIZ);
      zlog_err("Failed to find FEC %s upon delete", buf);
      return -1;
    }

  if (IS_ZEBRA_DEBUG_MPLS)
    {
      prefix2str(p, buf, BUFSIZ);
      zlog_debug ("Delete fec %s label index %u",
                  buf, fec->label_index);
    }

  old_label = fec->label;
  fec->flags &= ~FEC_FLAG_CONFIGURED;
  fec->label = MPLS_INVALID_LABEL;

  /* If no client exists, just delete the FEC. */
  if (list_isempty(fec->client_list))
    {
      fec_del (fec);
      return 0;
    }

  /* Derive the local label (from label index) or reset it. */
  fec_derive_label_from_index (zvrf, fec);
 
  /* If there is a label change, update clients. */
  if (fec->label == old_label)
    return 0;
  fec_update_clients (fec);

  /* Update label forwarding entries appropriately */
  return fec_change_update_lsp (zvrf, fec, old_label);
}

/*
 * Display MPLS FEC to label binding configuration (VTY command handler).
 */
int
zebra_mpls_write_fec_config (struct vty *vty, struct zebra_vrf *zvrf)
{
  struct route_node *rn;
  int af;
  zebra_fec_t *fec;
  char buf[BUFSIZ];
  int write = 0;

  for (af = AFI_IP; af < AFI_MAX; af++)
    {
      if (zvrf->fec_table[af] == NULL)
        continue;

      for (rn = route_top(zvrf->fec_table[af]); rn; rn = route_next(rn))
        {
          if (!rn->info)
            continue;

          char lstr[BUFSIZ];
          fec = rn->info;

          if (!(fec->flags & FEC_FLAG_CONFIGURED))
            continue;

          write = 1;
          prefix2str(&rn->p, buf, BUFSIZ);
          vty_outln (vty, "mpls label bind %s %s", buf,
                  label2str(fec->label, lstr, BUFSIZ));
        }
    }

  return write;
}

/*
 * Display MPLS FEC to label binding (VTY command handler).
 */
void
zebra_mpls_print_fec_table (struct vty *vty, struct zebra_vrf *zvrf)
{
  struct route_node *rn;
  int af;

  for (af = AFI_IP; af < AFI_MAX; af++)
    {
      if (zvrf->fec_table[af] == NULL)
        continue;

      for (rn = route_top(zvrf->fec_table[af]); rn; rn = route_next(rn))
        {
          if (!rn->info)
            continue;
          fec_print (rn->info, vty);
        }
    }
}

/*
 * Display MPLS FEC to label binding for a specific FEC (VTY command handler).
 */
void
zebra_mpls_print_fec (struct vty *vty, struct zebra_vrf *zvrf, struct prefix *p)
{
  struct route_table *table;
  struct route_node *rn;

  table = zvrf->fec_table[family2afi(PREFIX_FAMILY(p))];
  if (!table)
    return;

  apply_mask (p);
  rn = route_node_lookup(table, p);
  if (!rn)
    return;

  route_unlock_node(rn);
  if (!rn->info)
    return;

  fec_print (rn->info, vty);
}

/*
 * Install/uninstall a FEC-To-NHLFE (FTN) binding.
 */
int
mpls_ftn_update (int add, struct zebra_vrf *zvrf, enum lsp_types_t type,
		 struct prefix *prefix, enum nexthop_types_t gtype,
		 union g_addr *gate, ifindex_t ifindex, u_int8_t distance,
		 mpls_label_t out_label)
{
  struct route_table *table;
  struct route_node *rn;
  struct route_entry *re;
  struct nexthop *nexthop;

  /* Lookup table.  */
  table = zebra_vrf_table (family2afi(prefix->family), SAFI_UNICAST, zvrf_id (zvrf));
  if (! table)
    return -1;

  /* Lookup existing route */
  rn = route_node_get (table, prefix);
  RNODE_FOREACH_RE (rn, re)
    {
       if (CHECK_FLAG (re->status, ROUTE_ENTRY_REMOVED))
         continue;
       if (re->distance == distance)
         break;
    }

  if (re == NULL)
    return -1;

  for (nexthop = re->nexthop; nexthop; nexthop = nexthop->next)
    {
      switch (nexthop->type)
	{
	case NEXTHOP_TYPE_IPV4:
	case NEXTHOP_TYPE_IPV4_IFINDEX:
	  if (gtype != NEXTHOP_TYPE_IPV4 && gtype != NEXTHOP_TYPE_IPV4_IFINDEX)
	    continue;
	  if (! IPV4_ADDR_SAME (&nexthop->gate.ipv4, &gate->ipv4))
	    continue;
	  if (nexthop->type == NEXTHOP_TYPE_IPV4_IFINDEX &&
	      nexthop->ifindex != ifindex)
	    continue;
	  goto found;
	case NEXTHOP_TYPE_IPV6:
	case NEXTHOP_TYPE_IPV6_IFINDEX:
	  if (gtype != NEXTHOP_TYPE_IPV6 && gtype != NEXTHOP_TYPE_IPV6_IFINDEX)
	    continue;
	  if (! IPV6_ADDR_SAME (&nexthop->gate.ipv6, &gate->ipv6))
	    continue;
	  if (nexthop->type == NEXTHOP_TYPE_IPV6_IFINDEX &&
	      nexthop->ifindex != ifindex)
	    continue;
	  goto found;
	default:
	  break;
	}
    }
  /* nexthop not found */
  return -1;

 found:
  if (add && nexthop->nh_label_type == ZEBRA_LSP_NONE)
    nexthop_add_labels (nexthop, type, 1, &out_label);
  else if (!add && nexthop->nh_label_type == type)
    nexthop_del_labels (nexthop);
  else
    return 0;

  SET_FLAG (re->status, ROUTE_ENTRY_CHANGED);
  SET_FLAG (re->status, ROUTE_ENTRY_NEXTHOPS_CHANGED);
  rib_queue_add (rn);

  return 0;
}

/*
 * Install/update a NHLFE for an LSP in the forwarding table. This may be
 * a new LSP entry or a new NHLFE for an existing in-label or an update of
 * the out-label for an existing NHLFE (update case).
 */
int
mpls_lsp_install (struct zebra_vrf *zvrf, enum lsp_types_t type,
		  mpls_label_t in_label, mpls_label_t out_label,
		  enum nexthop_types_t gtype, union g_addr *gate,
		  ifindex_t ifindex)
{
  struct hash *lsp_table;
  zebra_ile_t tmp_ile;
  zebra_lsp_t *lsp;
  zebra_nhlfe_t *nhlfe;
  char buf[BUFSIZ];

  /* Lookup table. */
  lsp_table = zvrf->lsp_table;
  if (!lsp_table)
    return -1;

  /* If entry is present, exit. */
  tmp_ile.in_label = in_label;
  lsp = hash_get (lsp_table, &tmp_ile, lsp_alloc);
  if (!lsp)
    return -1;
  nhlfe = nhlfe_find (lsp, type, gtype, gate, ifindex);
  if (nhlfe)
    {
      struct nexthop *nh = nhlfe->nexthop;

      assert (nh);
      assert (nh->nh_label);

      /* Clear deleted flag (in case it was set) */
      UNSET_FLAG (nhlfe->flags, NHLFE_FLAG_DELETED);
      if (nh->nh_label->label[0] == out_label)
        /* No change */
        return 0;

      if (IS_ZEBRA_DEBUG_MPLS)
        {
          nhlfe2str (nhlfe, buf, BUFSIZ);
          zlog_debug ("LSP in-label %u type %d nexthop %s "
                      "out-label changed to %u (old %u)",
                      in_label, type, buf,
                      out_label, nh->nh_label->label[0]);
        }

      /* Update out label, trigger processing. */
      nh->nh_label->label[0] = out_label;
    }
  else
    {
      /* Add LSP entry to this nexthop */
      nhlfe = nhlfe_add (lsp, type, gtype, gate, ifindex, out_label);
      if (!nhlfe)
        return -1;

      if (IS_ZEBRA_DEBUG_MPLS)
        {
          nhlfe2str (nhlfe, buf, BUFSIZ);
          zlog_debug ("Add LSP in-label %u type %d nexthop %s "
                      "out-label %u", in_label, type, buf, out_label);
        }

      lsp->addr_family = NHLFE_FAMILY (nhlfe);
    }

  /* Mark NHLFE, queue LSP for processing. */
  SET_FLAG(nhlfe->flags, NHLFE_FLAG_CHANGED);
  if (lsp_processq_add (lsp))
    return -1;

  return 0;
}

/*
 * Uninstall a particular NHLFE in the forwarding table. If this is
 * the only NHLFE, the entire LSP forwarding entry has to be deleted.
 */
int
mpls_lsp_uninstall (struct zebra_vrf *zvrf, enum lsp_types_t type,
		    mpls_label_t in_label, enum nexthop_types_t gtype,
		    union g_addr *gate, ifindex_t ifindex)
{
  struct hash *lsp_table;
  zebra_ile_t tmp_ile;
  zebra_lsp_t *lsp;
  zebra_nhlfe_t *nhlfe;
  char buf[BUFSIZ];

  /* Lookup table. */
  lsp_table = zvrf->lsp_table;
  if (!lsp_table)
    return -1;

  /* If entry is not present, exit. */
  tmp_ile.in_label = in_label;
  lsp = hash_lookup (lsp_table, &tmp_ile);
  if (!lsp)
    return 0;
  nhlfe = nhlfe_find (lsp, type, gtype, gate, ifindex);
  if (!nhlfe)
    return 0;

  if (IS_ZEBRA_DEBUG_MPLS)
    {
      nhlfe2str (nhlfe, buf, BUFSIZ);
      zlog_debug ("Del LSP in-label %u type %d nexthop %s flags 0x%x",
                  in_label, type, buf, nhlfe->flags);
    }

  /* Mark NHLFE for delete or directly delete, as appropriate. */
  if (CHECK_FLAG(nhlfe->flags, NHLFE_FLAG_INSTALLED))
    {
      UNSET_FLAG (nhlfe->flags, NHLFE_FLAG_CHANGED);
      SET_FLAG (nhlfe->flags, NHLFE_FLAG_DELETED);
      if (lsp_processq_add (lsp))
        return -1;
    }
  else
    {
      nhlfe_del (nhlfe);

      /* Free LSP entry if no other NHLFEs and not scheduled. */
      if (!lsp->nhlfe_list &&
          !CHECK_FLAG (lsp->flags, LSP_FLAG_SCHEDULED))
        {
          if (IS_ZEBRA_DEBUG_MPLS)
            zlog_debug ("Free LSP in-label %u flags 0x%x",
                        lsp->ile.in_label, lsp->flags);

          lsp = hash_release(lsp_table, &lsp->ile);
          if (lsp)
            XFREE(MTYPE_LSP, lsp);
        }
    }
  return 0;
}

/*
 * Uninstall all LDP NHLFEs for a particular LSP forwarding entry.
 * If no other NHLFEs exist, the entry would be deleted.
 */
void
mpls_ldp_lsp_uninstall_all (struct hash_backet *backet, void *ctxt)
{
  zebra_lsp_t *lsp;
  struct hash *lsp_table;

  lsp = (zebra_lsp_t *) backet->data;
  if (!lsp || !lsp->nhlfe_list)
    return;

  lsp_table = ctxt;
  if (!lsp_table)
    return;

  mpls_lsp_uninstall_all (lsp_table, lsp, ZEBRA_LSP_LDP);
}

/*
 * Uninstall all LDP FEC-To-NHLFE (FTN) bindings of the given address-family.
 */
void
mpls_ldp_ftn_uninstall_all (struct zebra_vrf *zvrf, int afi)
{
  struct route_table *table;
  struct route_node *rn;
  struct route_entry *re;
  struct nexthop *nexthop;
  int update;

  /* Process routes of interested address-families. */
  table = zebra_vrf_table (afi, SAFI_UNICAST, zvrf_id (zvrf));
  if (!table)
    return;

  for (rn = route_top (table); rn; rn = route_next (rn))
    {
      update = 0;
      RNODE_FOREACH_RE (rn, re)
	for (nexthop = re->nexthop; nexthop; nexthop = nexthop->next)
	  if (nexthop->nh_label_type == ZEBRA_LSP_LDP)
	    {
	      nexthop_del_labels (nexthop);
	      SET_FLAG (re->status, ROUTE_ENTRY_CHANGED);
	      SET_FLAG (re->status, ROUTE_ENTRY_NEXTHOPS_CHANGED);
	      update = 1;
	    }

      if (update)
	rib_queue_add (rn);
    }
}

#if defined(HAVE_CUMULUS)
/*
 * Check that the label values used in LSP creation are consistent. The
 * main criteria is that if there is ECMP, the label operation must still
 * be consistent - i.e., all paths either do a swap or do PHP. This is due
 * to current HW restrictions.
 */
int
zebra_mpls_lsp_label_consistent (struct zebra_vrf *zvrf, mpls_label_t in_label,
                     mpls_label_t out_label, enum nexthop_types_t gtype,
                     union g_addr *gate, ifindex_t ifindex)
{
  struct hash *slsp_table;
  zebra_ile_t tmp_ile;
  zebra_slsp_t *slsp;
  zebra_snhlfe_t *snhlfe;

  /* Lookup table. */
  slsp_table = zvrf->slsp_table;
  if (!slsp_table)
    return 0;

  /* If entry is not present, exit. */
  tmp_ile.in_label = in_label;
  slsp = hash_lookup (slsp_table, &tmp_ile);
  if (!slsp)
    return 1;

  snhlfe = snhlfe_find (slsp, gtype, gate, ifindex);
  if (snhlfe)
    {
      if (snhlfe->out_label == out_label)
        return 1;

      /* If not only NHLFE, cannot allow label change. */
      if (snhlfe != slsp->snhlfe_list ||
          snhlfe->next)
        return 0;
    }
  else
    {
      /* If other NHLFEs exist, label operation must match. */
      if (slsp->snhlfe_list)
        {
          int cur_op, new_op;

          cur_op = (slsp->snhlfe_list->out_label == MPLS_IMP_NULL_LABEL);
          new_op = (out_label == MPLS_IMP_NULL_LABEL);
          if (cur_op != new_op)
            return 0;
        }
    }

  /* Label values are good. */
  return 1;
}
#endif /* HAVE_CUMULUS */

/*
 * Add static LSP entry. This may be the first entry for this incoming label
 * or an additional nexthop; an existing entry may also have outgoing label
 * changed.
 * Note: The label operation (swap or PHP) is common for the LSP entry (all
 * NHLFEs).
 */
int
zebra_mpls_static_lsp_add (struct zebra_vrf *zvrf, mpls_label_t in_label,
                     mpls_label_t out_label, enum nexthop_types_t gtype,
                     union g_addr *gate, ifindex_t ifindex)
{
  struct hash *slsp_table;
  zebra_ile_t tmp_ile;
  zebra_slsp_t *slsp;
  zebra_snhlfe_t *snhlfe;
  char buf[BUFSIZ];

  /* Lookup table. */
  slsp_table = zvrf->slsp_table;
  if (!slsp_table)
    return -1;

  /* If entry is present, exit. */
  tmp_ile.in_label = in_label;
  slsp = hash_get (slsp_table, &tmp_ile, slsp_alloc);
  if (!slsp)
    return -1;
  snhlfe = snhlfe_find (slsp, gtype, gate, ifindex);
  if (snhlfe)
    {
      if (snhlfe->out_label == out_label)
        /* No change */
        return 0;

      if (IS_ZEBRA_DEBUG_MPLS)
        {
          snhlfe2str (snhlfe, buf, BUFSIZ);
          zlog_debug ("Upd static LSP in-label %u nexthop %s "
                      "out-label %u (old %u)",
                      in_label, buf, out_label, snhlfe->out_label);
        }
      snhlfe->out_label = out_label;
    }
  else
    {
      /* Add static LSP entry to this nexthop */
      snhlfe = snhlfe_add (slsp, gtype, gate, ifindex, out_label);
      if (!snhlfe)
        return -1;

      if (IS_ZEBRA_DEBUG_MPLS)
        {
          snhlfe2str (snhlfe, buf, BUFSIZ);
          zlog_debug ("Add static LSP in-label %u nexthop %s out-label %u",
                      in_label, buf, out_label);
        }
    }

  /* (Re)Install LSP in the main table. */
  if (mpls_lsp_install (zvrf, ZEBRA_LSP_STATIC, in_label, out_label, gtype,
      gate, ifindex))
    return -1;

  return 0;
}

/*
 * Delete static LSP entry. This may be the delete of one particular
 * NHLFE for this incoming label or the delete of the entire entry (i.e.,
 * all NHLFEs).
 * NOTE: Delete of the only NHLFE will also end up deleting the entire
 * LSP configuration.
 */
int
zebra_mpls_static_lsp_del (struct zebra_vrf *zvrf, mpls_label_t in_label,
                           enum nexthop_types_t gtype, union g_addr *gate,
                           ifindex_t ifindex)
{
  struct hash *slsp_table;
  zebra_ile_t tmp_ile;
  zebra_slsp_t *slsp;
  zebra_snhlfe_t *snhlfe;

  /* Lookup table. */
  slsp_table = zvrf->slsp_table;
  if (!slsp_table)
    return -1;

  /* If entry is not present, exit. */
  tmp_ile.in_label = in_label;
  slsp = hash_lookup (slsp_table, &tmp_ile);
  if (!slsp)
    return 0;

  /* Is it delete of entire LSP or a specific NHLFE? */
  if (gtype == NEXTHOP_TYPE_BLACKHOLE)
    {
      if (IS_ZEBRA_DEBUG_MPLS)
        zlog_debug ("Del static LSP in-label %u", in_label);

      /* Uninstall entire LSP from the main table. */
      mpls_static_lsp_uninstall_all (zvrf, in_label);

      /* Delete all static NHLFEs */
      snhlfe_del_all (slsp);
    }
  else
    {
      /* Find specific NHLFE, exit if not found. */
      snhlfe = snhlfe_find (slsp, gtype, gate, ifindex);
      if (!snhlfe)
        return 0;

      if (IS_ZEBRA_DEBUG_MPLS)
        {
          char buf[BUFSIZ];
          snhlfe2str (snhlfe, buf, BUFSIZ);
          zlog_debug ("Del static LSP in-label %u nexthop %s",
                      in_label, buf);
        }

      /* Uninstall LSP from the main table. */
      mpls_lsp_uninstall (zvrf, ZEBRA_LSP_STATIC, in_label, gtype, gate,
			  ifindex);

      /* Delete static LSP NHLFE */
      snhlfe_del (snhlfe);
    }

  /* Remove entire static LSP entry if no NHLFE - valid in either case above. */
  if (!slsp->snhlfe_list)
    {
      slsp = hash_release(slsp_table, &tmp_ile);
      if (slsp)
        XFREE(MTYPE_SLSP, slsp);
    }

  return 0;
}

/*
 * Schedule all MPLS label forwarding entries for processing.
 * Called upon changes that may affect one or more of them such as
 * interface or nexthop state changes.
 */
void
zebra_mpls_lsp_schedule (struct zebra_vrf *zvrf)
{
  if (!zvrf)
    return;
  hash_iterate(zvrf->lsp_table, lsp_schedule, NULL);
}

/*
 * Display MPLS label forwarding table for a specific LSP
 * (VTY command handler).
 */
void
zebra_mpls_print_lsp (struct vty *vty, struct zebra_vrf *zvrf, mpls_label_t label,
                      u_char use_json)
{
  struct hash *lsp_table;
  zebra_lsp_t *lsp;
  zebra_ile_t tmp_ile;
  json_object *json = NULL;

  /* Lookup table. */
  lsp_table = zvrf->lsp_table;
  if (!lsp_table)
    return;

  /* If entry is not present, exit. */
  tmp_ile.in_label = label;
  lsp = hash_lookup (lsp_table, &tmp_ile);
  if (!lsp)
    return;

  if (use_json)
    {
      json = lsp_json(lsp);
      vty_outln (vty, "%s",
                 json_object_to_json_string_ext(json, JSON_C_TO_STRING_PRETTY));
      json_object_free(json);
    }
  else
    lsp_print (lsp, (void *)vty);
}

/*
 * Display MPLS label forwarding table (VTY command handler).
 */
void
zebra_mpls_print_lsp_table (struct vty *vty, struct zebra_vrf *zvrf,
                            u_char use_json)
{
  char buf[BUFSIZ];
  json_object *json = NULL;
  zebra_lsp_t *lsp = NULL;
  zebra_nhlfe_t *nhlfe = NULL;
  struct nexthop *nexthop = NULL;
  struct listnode *node = NULL;
  struct list *lsp_list = hash_get_sorted_list(zvrf->lsp_table, lsp_cmp);

  if (use_json)
    {
      json  = json_object_new_object();

      for (ALL_LIST_ELEMENTS_RO(lsp_list, node, lsp))
        json_object_object_add(json, label2str(lsp->ile.in_label, buf, BUFSIZ),
                               lsp_json(lsp));

      vty_outln (vty, "%s",
                 json_object_to_json_string_ext(json, JSON_C_TO_STRING_PRETTY));
      json_object_free(json);
    }
  else
    {
      vty_outln (vty, " Inbound                            Outbound");
      vty_outln (vty, "   Label     Type          Nexthop     Label");
      vty_outln (vty, "--------  -------  ---------------  --------");

      for (ALL_LIST_ELEMENTS_RO(lsp_list, node, lsp))
        {
          for (nhlfe = lsp->nhlfe_list; nhlfe; nhlfe = nhlfe->next)
            {
              vty_out (vty, "%8d  %7s  ", lsp->ile.in_label, nhlfe_type2str(nhlfe->type));
              nexthop = nhlfe->nexthop;

              switch (nexthop->type)
                {
                case NEXTHOP_TYPE_IPV4:
                case NEXTHOP_TYPE_IPV4_IFINDEX:
                  vty_out (vty, "%15s", inet_ntoa (nexthop->gate.ipv4));
                  break;
                case NEXTHOP_TYPE_IPV6:
                case NEXTHOP_TYPE_IPV6_IFINDEX:
                  vty_out (vty, "%15s", inet_ntop (AF_INET6, &nexthop->gate.ipv6, buf, BUFSIZ));
                  break;
                default:
                  break;
                }

              vty_outln (vty, "  %8d", nexthop->nh_label->label[0]);
            }
        }

      vty_out (vty, VTYNL);
    }

  list_delete (lsp_list);
}

/*
 * Display MPLS LSP configuration of all static LSPs (VTY command handler).
 */
int
zebra_mpls_write_lsp_config (struct vty *vty, struct zebra_vrf *zvrf)
{
  zebra_slsp_t *slsp;
  zebra_snhlfe_t *snhlfe;
  struct listnode *node;
  struct list *slsp_list = hash_get_sorted_list(zvrf->slsp_table, slsp_cmp);

  for (ALL_LIST_ELEMENTS_RO(slsp_list, node, slsp))
      {
        for (snhlfe = slsp->snhlfe_list; snhlfe; snhlfe = snhlfe->next)
          {
	    char buf[INET6_ADDRSTRLEN];
            char lstr[30];

            snhlfe2str (snhlfe, buf, BUFSIZ);
	    switch (snhlfe->out_label) {
	      case MPLS_V4_EXP_NULL_LABEL:
	      case MPLS_V6_EXP_NULL_LABEL:
		strlcpy(lstr, "explicit-null", sizeof(lstr));
		break;
	      case MPLS_IMP_NULL_LABEL:
		strlcpy(lstr, "implicit-null", sizeof(lstr));
		break;
	      default:
		sprintf(lstr, "%u", snhlfe->out_label);
		break;
	    }

            vty_outln (vty, "mpls lsp %u %s %s",
                     slsp->ile.in_label, buf, lstr);
          }
      }

  list_delete (slsp_list);
  return (zvrf->slsp_table->count ? 1 : 0);
}

/*
 * Add/update global label block.
 */
int
zebra_mpls_label_block_add (struct zebra_vrf *zvrf, u_int32_t start_label,
                            u_int32_t end_label)
{
  zvrf->mpls_srgb.start_label = start_label;
  zvrf->mpls_srgb.end_label = end_label;

  /* Evaluate registered FECs to see if any get a label or not. */
  fec_evaluate (zvrf);
  return 0;
}

/*
 * Delete global label block.
 */
int
zebra_mpls_label_block_del (struct zebra_vrf *zvrf)
{
  zvrf->mpls_srgb.start_label = MPLS_DEFAULT_MIN_SRGB_LABEL;
  zvrf->mpls_srgb.end_label = MPLS_DEFAULT_MAX_SRGB_LABEL;

  /* Process registered FECs to clear their local label, if needed. */
  fec_evaluate (zvrf);
  return 0;
}

/*
 * Display MPLS global label block configuration (VTY command handler).
 */
int
zebra_mpls_write_label_block_config (struct vty *vty, struct zebra_vrf *zvrf)
{
  if (zvrf->mpls_srgb.start_label == 0)
    return 0;

  if ((zvrf->mpls_srgb.start_label != MPLS_DEFAULT_MIN_SRGB_LABEL) ||
      (zvrf->mpls_srgb.end_label != MPLS_DEFAULT_MAX_SRGB_LABEL))
    {
      vty_outln (vty, "mpls label global-block %u %u",
              zvrf->mpls_srgb.start_label,zvrf->mpls_srgb.end_label);
    }

  return 1;
}

/*
 * Called upon process exiting, need to delete LSP forwarding
 * entries from the kernel.
 * NOTE: Currently supported only for default VRF.
 */
void
zebra_mpls_close_tables (struct zebra_vrf *zvrf)
{
  hash_iterate(zvrf->lsp_table, lsp_uninstall_from_kernel, NULL);
  hash_clean(zvrf->lsp_table, NULL);
  hash_free(zvrf->lsp_table);
  hash_clean(zvrf->slsp_table, NULL);
  hash_free(zvrf->slsp_table);
}

/*
 * Allocate MPLS tables for this VRF and do other initialization.
 * NOTE: Currently supported only for default VRF.
 */
void
zebra_mpls_init_tables (struct zebra_vrf *zvrf)
{
  if (!zvrf)
    return;
  zvrf->slsp_table = hash_create(label_hash, label_cmp);
  zvrf->lsp_table = hash_create(label_hash, label_cmp);
  zvrf->fec_table[AFI_IP] = route_table_init();
  zvrf->fec_table[AFI_IP6] = route_table_init();
  zvrf->mpls_flags = 0;
  zvrf->mpls_srgb.start_label = MPLS_DEFAULT_MIN_SRGB_LABEL;
  zvrf->mpls_srgb.end_label = MPLS_DEFAULT_MAX_SRGB_LABEL;
}

/*
 * Global MPLS initialization.
 */
void
zebra_mpls_init (void)
{
  mpls_enabled = 0;

  if (mpls_kernel_init () < 0)
    {
      zlog_warn ("Disabling MPLS support (no kernel support)");
      return;
    }

  if (! mpls_processq_init (&zebrad))
    mpls_enabled = 1;
}