*: use an ifindex_t type, defined in lib/if.h, for ifindex values

[mirror_frr.git] / zebra / zserv.c

/* Zebra daemon server routine.
 * Copyright (C) 1997, 98, 99 Kunihiro Ishiguro
 *
 * This file is part of GNU Zebra.
 *
 * GNU Zebra is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2, or (at your option) any
 * later version.
 *
 * GNU Zebra is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with GNU Zebra; see the file COPYING.  If not, write to the 
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330, 
 * Boston, MA 02111-1307, USA.  
 */

#include <zebra.h>

#include "prefix.h"
#include "command.h"
#include "if.h"
#include "thread.h"
#include "stream.h"
#include "memory.h"
#include "table.h"
#include "rib.h"
#include "network.h"
#include "sockunion.h"
#include "log.h"
#include "zclient.h"
#include "privs.h"
#include "network.h"
#include "buffer.h"
#include "nexthop.h"
#include "vrf.h"

#include "zebra/zserv.h"
#include "zebra/zebra_ns.h"
#include "zebra/zebra_vrf.h"
#include "zebra/router-id.h"
#include "zebra/redistribute.h"
#include "zebra/debug.h"
#include "zebra/ipforward.h"
#include "zebra/zebra_rnh.h"
#include "zebra/rt_netlink.h"
#include "zebra/interface.h"
#include "zebra/zebra_ptm.h"
#include "zebra/rtadv.h"

/* Event list of zebra. */
enum event { ZEBRA_SERV, ZEBRA_READ, ZEBRA_WRITE };

static void zebra_event (enum event event, int sock, struct zserv *client);

extern struct zebra_privs_t zserv_privs;

static void zebra_client_close (struct zserv *client);

static int
zserv_delayed_close(struct thread *thread)
{
  struct zserv *client = THREAD_ARG(thread);

  client->t_suicide = NULL;
  zebra_client_close(client);
  return 0;
}

static int
zserv_flush_data(struct thread *thread)
{
  struct zserv *client = THREAD_ARG(thread);

  client->t_write = NULL;
  if (client->t_suicide)
    {
      zebra_client_close(client);
      return -1;
    }
  switch (buffer_flush_available(client->wb, client->sock))
    {
    case BUFFER_ERROR:
      zlog_warn("%s: buffer_flush_available failed on zserv client fd %d, "
                "closing", __func__, client->sock);
      zebra_client_close(client);
      break;
    case BUFFER_PENDING:
      client->t_write = thread_add_write(zebrad.master, zserv_flush_data,
                                         client, client->sock);
      break;
    case BUFFER_EMPTY:
      break;
    }

  client->last_write_time = quagga_monotime();
  return 0;
}

int
zebra_server_send_message(struct zserv *client)
{
  if (client->t_suicide)
    return -1;

  stream_set_getp(client->obuf, 0);
  client->last_write_cmd = stream_getw_from(client->obuf, 6);
  switch (buffer_write(client->wb, client->sock, STREAM_DATA(client->obuf),
                       stream_get_endp(client->obuf)))
    {
    case BUFFER_ERROR:
      zlog_warn("%s: buffer_write failed to zserv client fd %d, closing",
                 __func__, client->sock);
      /* Schedule a delayed close since many of the functions that call this
         one do not check the return code.  They do not allow for the
         possibility that an I/O error may have caused the client to be
         deleted. */
      client->t_suicide = thread_add_event(zebrad.master, zserv_delayed_close,
                                           client, 0);
      return -1;
    case BUFFER_EMPTY:
      THREAD_OFF(client->t_write);
      break;
    case BUFFER_PENDING:
      THREAD_WRITE_ON(zebrad.master, client->t_write,
                      zserv_flush_data, client, client->sock);
      break;
    }

  client->last_write_time = quagga_monotime();
  return 0;
}

void
zserv_create_header (struct stream *s, uint16_t cmd, vrf_id_t vrf_id)
{
  /* length placeholder, caller can update */
  stream_putw (s, ZEBRA_HEADER_SIZE);
  stream_putc (s, ZEBRA_HEADER_MARKER);
  stream_putc (s, ZSERV_VERSION);
  stream_putw (s, vrf_id);
  stream_putw (s, cmd);
}

static void
zserv_encode_interface (struct stream *s, struct interface *ifp)
{
  /* Interface information. */
  stream_put (s, ifp->name, INTERFACE_NAMSIZ);
  stream_putl (s, ifp->ifindex);
  stream_putc (s, ifp->status);
  stream_putq (s, ifp->flags);
  stream_putc (s, ifp->ptm_enable);
  stream_putc (s, ifp->ptm_status);
  stream_putl (s, ifp->metric);
  stream_putl (s, ifp->mtu);
  stream_putl (s, ifp->mtu6);
  stream_putl (s, ifp->bandwidth);
#ifdef HAVE_STRUCT_SOCKADDR_DL
  stream_put (s, &ifp->sdl, sizeof (ifp->sdl_storage));
#else
  stream_putl (s, ifp->hw_addr_len);
  if (ifp->hw_addr_len)
    stream_put (s, ifp->hw_addr, ifp->hw_addr_len);
#endif /* HAVE_STRUCT_SOCKADDR_DL */

  /* Write packet size. */
  stream_putw_at (s, 0, stream_get_endp (s));
}

static void
zserv_encode_vrf (struct stream *s, struct zebra_vrf *zvrf)
{
  /* Interface information. */
  stream_put (s, zvrf->name, VRF_NAMSIZ);

  /* Write packet size. */
  stream_putw_at (s, 0, stream_get_endp (s));
}

/* Interface is added. Send ZEBRA_INTERFACE_ADD to client. */
/*
 * This function is called in the following situations:
 * - in response to a 3-byte ZEBRA_INTERFACE_ADD request
 *   from the client.
 * - at startup, when zebra figures out the available interfaces
 * - when an interface is added (where support for
 *   RTM_IFANNOUNCE or AF_NETLINK sockets is available), or when
 *   an interface is marked IFF_UP (i.e., an RTM_IFINFO message is
 *   received)
 */
int
zsend_interface_add (struct zserv *client, struct interface *ifp)
{
  struct stream *s;

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

  zserv_create_header (s, ZEBRA_INTERFACE_ADD, ifp->vrf_id);
  zserv_encode_interface (s, ifp);

  client->ifadd_cnt++;
  return zebra_server_send_message(client);
}

/* Interface deletion from zebra daemon. */
int
zsend_interface_delete (struct zserv *client, struct interface *ifp)
{
  struct stream *s;

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

  zserv_create_header (s, ZEBRA_INTERFACE_DELETE, ifp->vrf_id);
  zserv_encode_interface (s, ifp);

  client->ifdel_cnt++;
  return zebra_server_send_message (client);
}

int
zsend_vrf_add (struct zserv *client, struct zebra_vrf *zvrf)
{
  struct stream *s;

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

  zserv_create_header (s, ZEBRA_VRF_ADD, zvrf->vrf_id);
  zserv_encode_vrf (s, zvrf);

  client->vrfadd_cnt++;
  return zebra_server_send_message(client);
}

/* VRF deletion from zebra daemon. */
int
zsend_vrf_delete (struct zserv *client, struct zebra_vrf *zvrf)
{
  struct stream *s;

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

  zserv_create_header (s, ZEBRA_VRF_DELETE, zvrf->vrf_id);
  zserv_encode_vrf (s, zvrf);

  client->vrfdel_cnt++;
  return zebra_server_send_message (client);
}

/* Interface address is added/deleted. Send ZEBRA_INTERFACE_ADDRESS_ADD or
 * ZEBRA_INTERFACE_ADDRESS_DELETE to the client. 
 *
 * A ZEBRA_INTERFACE_ADDRESS_ADD is sent in the following situations:
 * - in response to a 3-byte ZEBRA_INTERFACE_ADD request
 *   from the client, after the ZEBRA_INTERFACE_ADD has been
 *   sent from zebra to the client
 * - redistribute new address info to all clients in the following situations
 *    - at startup, when zebra figures out the available interfaces
 *    - when an interface is added (where support for
 *      RTM_IFANNOUNCE or AF_NETLINK sockets is available), or when
 *      an interface is marked IFF_UP (i.e., an RTM_IFINFO message is
 *      received)
 *    - for the vty commands "ip address A.B.C.D/M [<secondary>|<label LINE>]"
 *      and "no bandwidth <1-10000000>", "ipv6 address X:X::X:X/M"
 *    - when an RTM_NEWADDR message is received from the kernel,
 * 
 * The call tree that triggers ZEBRA_INTERFACE_ADDRESS_DELETE: 
 *
 *                   zsend_interface_address(DELETE)
 *                           ^                         
 *                           |                        
 *          zebra_interface_address_delete_update    
 *             ^                        ^      ^
 *             |                        |      if_delete_update
 *             |                        |
 *         ip_address_uninstall        connected_delete_ipv4
 *         [ipv6_addresss_uninstall]   [connected_delete_ipv6]
 *             ^                        ^
 *             |                        |
 *             |                  RTM_NEWADDR on routing/netlink socket
 *             |
 *         vty commands:
 *     "no ip address A.B.C.D/M [label LINE]"
 *     "no ip address A.B.C.D/M secondary"
 *     ["no ipv6 address X:X::X:X/M"]
 *
 */
int
zsend_interface_address (int cmd, struct zserv *client, 
                         struct interface *ifp, struct connected *ifc)
{
  int blen;
  struct stream *s;
  struct prefix *p;

  s = client->obuf;
  stream_reset (s);
  
  zserv_create_header (s, cmd, ifp->vrf_id);
  stream_putl (s, ifp->ifindex);

  /* Interface address flag. */
  stream_putc (s, ifc->flags);

  /* Prefix information. */
  p = ifc->address;
  stream_putc (s, p->family);
  blen = prefix_blen (p);
  stream_put (s, &p->u.prefix, blen);

  /* 
   * XXX gnu version does not send prefixlen for ZEBRA_INTERFACE_ADDRESS_DELETE
   * but zebra_interface_address_delete_read() in the gnu version 
   * expects to find it
   */
  stream_putc (s, p->prefixlen);

  /* Destination. */
  p = ifc->destination;
  if (p)
    stream_put (s, &p->u.prefix, blen);
  else
    stream_put (s, NULL, blen);

  /* Write packet size. */
  stream_putw_at (s, 0, stream_get_endp (s));

  client->connected_rt_add_cnt++;
  return zebra_server_send_message(client);
}

static int
zsend_interface_nbr_address (int cmd, struct zserv *client,
                             struct interface *ifp, struct nbr_connected *ifc)
{
  int blen;
  struct stream *s;
  struct prefix *p;

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

  zserv_create_header (s, cmd, ifp->vrf_id);
  stream_putl (s, ifp->ifindex);

  /* Prefix information. */
  p = ifc->address;
  stream_putc (s, p->family);
  blen = prefix_blen (p);
  stream_put (s, &p->u.prefix, blen);

  /*
   * XXX gnu version does not send prefixlen for ZEBRA_INTERFACE_ADDRESS_DELETE
   * but zebra_interface_address_delete_read() in the gnu version
   * expects to find it
   */
  stream_putc (s, p->prefixlen);

  /* Write packet size. */
  stream_putw_at (s, 0, stream_get_endp (s));

  return zebra_server_send_message(client);
}

/* Interface address addition. */
static void
zebra_interface_nbr_address_add_update (struct interface *ifp,
                                        struct nbr_connected *ifc)
{
  struct listnode *node, *nnode;
  struct zserv *client;
  struct prefix *p;

  if (IS_ZEBRA_DEBUG_EVENT)
    {
      char buf[INET6_ADDRSTRLEN];

      p = ifc->address;
      zlog_debug ("MESSAGE: ZEBRA_INTERFACE_NBR_ADDRESS_ADD %s/%d on %s",
      inet_ntop (p->family, &p->u.prefix, buf, INET6_ADDRSTRLEN),
      p->prefixlen, ifc->ifp->name);
    }

  for (ALL_LIST_ELEMENTS (zebrad.client_list, node, nnode, client))
    zsend_interface_nbr_address (ZEBRA_INTERFACE_NBR_ADDRESS_ADD, client, ifp, ifc);
}

/* Interface address deletion. */
static void
zebra_interface_nbr_address_delete_update (struct interface *ifp,
                                           struct nbr_connected *ifc)
{
  struct listnode *node, *nnode;
  struct zserv *client;
  struct prefix *p;

  if (IS_ZEBRA_DEBUG_EVENT)
    {
      char buf[INET6_ADDRSTRLEN];

      p = ifc->address;
      zlog_debug ("MESSAGE: ZEBRA_INTERFACE_NBR_ADDRESS_DELETE %s/%d on %s",
                  inet_ntop (p->family, &p->u.prefix, buf, INET6_ADDRSTRLEN),
                 p->prefixlen, ifc->ifp->name);
    }

  for (ALL_LIST_ELEMENTS (zebrad.client_list, node, nnode, client))
    zsend_interface_nbr_address (ZEBRA_INTERFACE_NBR_ADDRESS_DELETE, client, ifp, ifc);
}

/* Send addresses on interface to client */
int
zsend_interface_addresses (struct zserv *client, struct interface *ifp)
{
  struct listnode *cnode, *cnnode;
  struct connected *c;
  struct nbr_connected *nc;

  /* Send interface addresses. */
  for (ALL_LIST_ELEMENTS (ifp->connected, cnode, cnnode, c))
    {
      if (!CHECK_FLAG (c->conf, ZEBRA_IFC_REAL))
        continue;

      if (zsend_interface_address (ZEBRA_INTERFACE_ADDRESS_ADD, client,
                                   ifp, c) < 0)
        return -1;
    }

  /* Send interface neighbors. */
  for (ALL_LIST_ELEMENTS (ifp->nbr_connected, cnode, cnnode, nc))
    {
      if (zsend_interface_nbr_address (ZEBRA_INTERFACE_NBR_ADDRESS_ADD,
                                       client, ifp, nc) < 0)
        return -1;
    }

  return 0;
}

/* Notify client about interface moving from one VRF to another.
 * Whether client is interested in old and new VRF is checked by caller.
 */
int
zsend_interface_vrf_update (struct zserv *client, struct interface *ifp,
                            vrf_id_t vrf_id)
{
  struct stream *s;

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

  zserv_create_header (s, ZEBRA_INTERFACE_VRF_UPDATE, ifp->vrf_id);

  /* Fill in the ifIndex of the interface and its new VRF (id) */
  stream_putl (s, ifp->ifindex);
  stream_putw (s, vrf_id);

  /* Write packet size. */
  stream_putw_at (s, 0, stream_get_endp (s));

  client->if_vrfchg_cnt++;
  return zebra_server_send_message(client);
}

/* Add new nbr connected IPv6 address */
void
nbr_connected_add_ipv6 (struct interface *ifp, struct in6_addr *address)
{
  struct nbr_connected *ifc;
  struct prefix p;

  p.family = AF_INET6;
  IPV6_ADDR_COPY (&p.u.prefix, address);
  p.prefixlen = IPV6_MAX_PREFIXLEN;

  if (!(ifc = listnode_head(ifp->nbr_connected)))
    {
      /* new addition */
      ifc = nbr_connected_new ();
      ifc->address = prefix_new();
      ifc->ifp = ifp;
      listnode_add (ifp->nbr_connected, ifc);
    }

  prefix_copy(ifc->address, &p);

  zebra_interface_nbr_address_add_update (ifp, ifc);

  if_nbr_ipv6ll_to_ipv4ll_neigh_update (ifp, address, 1);
}

void
nbr_connected_delete_ipv6 (struct interface *ifp, struct in6_addr *address)
{
  struct nbr_connected *ifc;
  struct prefix p;

  p.family = AF_INET6;
  IPV6_ADDR_COPY (&p.u.prefix, address);
  p.prefixlen = IPV6_MAX_PREFIXLEN;

  ifc = nbr_connected_check(ifp, &p);
  if (!ifc)
    return;

  listnode_delete (ifp->nbr_connected, ifc);

  zebra_interface_nbr_address_delete_update (ifp, ifc);

  if_nbr_ipv6ll_to_ipv4ll_neigh_update (ifp, address, 0);

  nbr_connected_free (ifc);
}

/*
 * The cmd passed to zsend_interface_update  may be ZEBRA_INTERFACE_UP or
 * ZEBRA_INTERFACE_DOWN.
 *
 * The ZEBRA_INTERFACE_UP message is sent from the zebra server to
 * the clients in one of 2 situations:
 *   - an if_up is detected e.g., as a result of an RTM_IFINFO message
 *   - a vty command modifying the bandwidth of an interface is received.
 * The ZEBRA_INTERFACE_DOWN message is sent when an if_down is detected.
 */
int
zsend_interface_update (int cmd, struct zserv *client, struct interface *ifp)
{
  struct stream *s;

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

  zserv_create_header (s, cmd, ifp->vrf_id);
  zserv_encode_interface (s, ifp);

  if (cmd == ZEBRA_INTERFACE_UP)
    client->ifup_cnt++;
  else
    client->ifdown_cnt++;

  return zebra_server_send_message(client);
}

/*
 * This is the new function to announce and withdraw redistributed routes, used
 * by Zebra. This is the old zsend_route_multipath() function. That function
 * was duplicating code to send a lot of information that was essentially thrown
 * away or ignored by the receiver. This is the leaner function that is not a
 * duplicate of the zapi_ipv4_route_add/del.
 *
 * The primary difference is that this function merely sends a single NH instead of
 * all the nexthops.
 */
int
zsend_redistribute_route (int cmd, struct zserv *client, struct prefix *p,
                          struct rib *rib)
{
  int psize;
  struct stream *s;
  struct nexthop *nexthop;
  unsigned long nhnummark = 0, messmark = 0;
  int nhnum = 0;
  u_char zapi_flags = 0;
  struct nexthop dummy_nh;

  /* Came from VRF lib patch, is this really needed? callers of this routine
     do check for redist.., so may be its not needed.
     Check this client need this route.
  if (!vrf_bitmap_check (client->redist[family2afi(p->family)][rib->type],
                         rib->vrf_id) &&
      !(is_default (p) &&
        vrf_bitmap_check (client->redist_default, rib->vrf_id)))
    return 0;
  */

  s = client->obuf;
  stream_reset (s);
  memset(&dummy_nh, 0, sizeof(struct nexthop));

  zserv_create_header (s, cmd, rib->vrf_id);
  
  /* Put type and nexthop. */
  stream_putc (s, rib->type);
  stream_putw (s, rib->instance);
  stream_putc (s, rib->flags);

  /* marker for message flags field */
  messmark = stream_get_endp (s);
  stream_putc (s, 0);

  /* Prefix. */
  psize = PSIZE (p->prefixlen);
  stream_putc (s, p->prefixlen);
  stream_write (s, (u_char *) & p->u.prefix, psize);

  for (nexthop = rib->nexthop; nexthop; nexthop = nexthop->next)
    {
      /* We don't send any nexthops when there's a multipath */
      if (rib->nexthop_active_num > 1)
        {
          SET_FLAG (zapi_flags, ZAPI_MESSAGE_NEXTHOP);
          SET_FLAG (zapi_flags, ZAPI_MESSAGE_IFINDEX);

          stream_putc(s, 1);
          if (p->family == AF_INET)
            {
              stream_put_in_addr (s, &dummy_nh.gate.ipv4);
            }
          else if (p->family == AF_INET6)
            {
                stream_write (s, (u_char *) &dummy_nh.gate.ipv6, 16);
            }
          else
            {
              /* We don't handle anything else now, abort */
              zlog_err("%s: Unable to redistribute route of unknown family, %d\n",
                       __func__, p->family);
              return -1;
            }
          stream_putc (s, 1);
          stream_putl (s, 0);   /* dummy ifindex */
          break;
        }

      if (CHECK_FLAG(nexthop->flags, NEXTHOP_FLAG_FIB)
          || nexthop_has_fib_child(nexthop))
        {
          SET_FLAG (zapi_flags, ZAPI_MESSAGE_NEXTHOP);
          SET_FLAG (zapi_flags, ZAPI_MESSAGE_IFINDEX);
          if (nhnummark == 0)
            {
              nhnummark = stream_get_endp (s);
              stream_putc (s, 1); /* placeholder */
            }
          nhnum++;

          switch(nexthop->type) 
            {
              case NEXTHOP_TYPE_IPV4:
              case NEXTHOP_TYPE_IPV4_IFINDEX:
                stream_put_in_addr (s, &nexthop->gate.ipv4);
                break;
              case NEXTHOP_TYPE_IPV6:
              case NEXTHOP_TYPE_IPV6_IFINDEX:
                /* Only BGP supports IPv4 prefix with IPv6 NH, so kill this */
                if (p->family == AF_INET)
                  stream_put_in_addr(s, &dummy_nh.gate.ipv4);
                else
                  stream_write (s, (u_char *) &nexthop->gate.ipv6, 16);
                break;
              default:
                if (cmd == ZEBRA_REDISTRIBUTE_IPV4_ADD
                    || cmd == ZEBRA_REDISTRIBUTE_IPV4_DEL)
                  {
                    struct in_addr empty;
                    memset (&empty, 0, sizeof (struct in_addr));
                    stream_write (s, (u_char *) &empty, IPV4_MAX_BYTELEN);
                  }
                else
                  {
                    struct in6_addr empty;
                    memset (&empty, 0, sizeof (struct in6_addr));
                    stream_write (s, (u_char *) &empty, IPV6_MAX_BYTELEN);
                  }
              }

          /* Interface index. */
          stream_putc (s, 1);
          stream_putl (s, nexthop->ifindex);

          break;
        }
    }

  /* Metric */
  if (cmd == ZEBRA_REDISTRIBUTE_IPV4_ADD || cmd == ZEBRA_REDISTRIBUTE_IPV6_ADD)
    {
      SET_FLAG (zapi_flags, ZAPI_MESSAGE_DISTANCE);
      stream_putc (s, rib->distance);
      SET_FLAG (zapi_flags, ZAPI_MESSAGE_METRIC);
      stream_putl (s, rib->metric);

      /* tag */
      if (rib->tag)
        {
          SET_FLAG(zapi_flags, ZAPI_MESSAGE_TAG);
          stream_putw(s, rib->tag);
        }
    }

  /* write real message flags value */
  stream_putc_at (s, messmark, zapi_flags);

  /* Write next-hop number */
  if (nhnummark)
    stream_putc_at (s, nhnummark, nhnum);

  /* Write packet size. */
  stream_putw_at (s, 0, stream_get_endp (s));

  return zebra_server_send_message(client);
}

#ifdef HAVE_IPV6
static int
zsend_ipv6_nexthop_lookup (struct zserv *client, struct in6_addr *addr,
    vrf_id_t vrf_id)
{
  struct stream *s;
  struct rib *rib;
  unsigned long nump;
  u_char num;
  struct nexthop *nexthop;

  /* Lookup nexthop. */
  rib = rib_match_ipv6 (addr, vrf_id);

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

  /* Fill in result. */
  zserv_create_header (s, ZEBRA_IPV6_NEXTHOP_LOOKUP, vrf_id);
  stream_put (s, addr, 16);

  if (rib)
    {
      stream_putl (s, rib->metric);
      num = 0;
      nump = stream_get_endp(s);
      stream_putc (s, 0);
      /* Only non-recursive routes are elegible to resolve nexthop we
       * are looking up. Therefore, we will just iterate over the top
       * chain of nexthops. */
      for (nexthop = rib->nexthop; nexthop; nexthop = nexthop->next)
        if (CHECK_FLAG (nexthop->flags, NEXTHOP_FLAG_FIB))
          {
            stream_putc (s, nexthop->type);
            switch (nexthop->type)
              {
              case ZEBRA_NEXTHOP_IPV6:
                stream_put (s, &nexthop->gate.ipv6, 16);
                break;
              case ZEBRA_NEXTHOP_IPV6_IFINDEX:
                stream_put (s, &nexthop->gate.ipv6, 16);
                stream_putl (s, nexthop->ifindex);
                break;
              case ZEBRA_NEXTHOP_IFINDEX:
                stream_putl (s, nexthop->ifindex);
                break;
              default:
                /* do nothing */
                break;
              }
            num++;
          }
      stream_putc_at (s, nump, num);
    }
  else
    {
      stream_putl (s, 0);
      stream_putc (s, 0);
    }

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

  return zebra_server_send_message(client);
}
#endif /* HAVE_IPV6 */

static int
zsend_ipv4_nexthop_lookup (struct zserv *client, struct in_addr addr,
    vrf_id_t vrf_id)
{
  struct stream *s;
  struct rib *rib;
  unsigned long nump;
  u_char num;
  struct nexthop *nexthop;

  /* Lookup nexthop. */
  rib = rib_match_ipv4 (addr, SAFI_UNICAST, vrf_id, NULL);

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

  /* Fill in result. */
  zserv_create_header (s, ZEBRA_IPV4_NEXTHOP_LOOKUP, vrf_id);
  stream_put_in_addr (s, &addr);

  if (rib)
    {
      if (IS_ZEBRA_DEBUG_PACKET && IS_ZEBRA_DEBUG_RECV)
        zlog_debug("%s: Matching rib entry found.", __func__);
      stream_putl (s, rib->metric);
      num = 0;
      nump = stream_get_endp(s);
      stream_putc (s, 0);
      /* Only non-recursive routes are elegible to resolve the nexthop we
       * are looking up. Therefore, we will just iterate over the top
       * chain of nexthops. */
      for (nexthop = rib->nexthop; nexthop; nexthop = nexthop->next)
        if (CHECK_FLAG (nexthop->flags, NEXTHOP_FLAG_FIB))
          {
            stream_putc (s, nexthop->type);
            switch (nexthop->type)
              {
              case ZEBRA_NEXTHOP_IPV4:
                stream_put_in_addr (s, &nexthop->gate.ipv4);
                break;
              case ZEBRA_NEXTHOP_IPV4_IFINDEX:
                stream_put_in_addr (s, &nexthop->gate.ipv4);
                stream_putl (s, nexthop->ifindex);
                break;
              case ZEBRA_NEXTHOP_IFINDEX:
                stream_putl (s, nexthop->ifindex);
                break;
              default:
                /* do nothing */
                break;
              }
            num++;
          }
      stream_putc_at (s, nump, num);
    }
  else
    {
      if (IS_ZEBRA_DEBUG_PACKET && IS_ZEBRA_DEBUG_RECV)
        zlog_debug("%s: No matching rib entry found.", __func__);
      stream_putl (s, 0);
      stream_putc (s, 0);
    }

  stream_putw_at (s, 0, stream_get_endp (s));
  
  return zebra_server_send_message(client);
}

/* Nexthop register */
static int
zserv_rnh_register (struct zserv *client, int sock, u_short length,
                    rnh_type_t type, struct zebra_vrf *zvrf)
{
  struct rnh *rnh;
  struct stream *s;
  struct prefix p;
  u_short l = 0;
  u_char flags = 0;

  if (IS_ZEBRA_DEBUG_NHT)
    zlog_debug("rnh_register msg from client %s: length=%d, type=%s\n",
               zebra_route_string(client->proto), length,
               (type == RNH_NEXTHOP_TYPE) ? "nexthop" : "route");

  s = client->ibuf;

  client->nh_reg_time = quagga_monotime();

  while (l < length)
    {
      flags = stream_getc(s);
      p.family = stream_getw(s);
      p.prefixlen = stream_getc(s);
      l += 4;
      if (p.family == AF_INET)
        {
          p.u.prefix4.s_addr = stream_get_ipv4(s);
          l += IPV4_MAX_BYTELEN;
        }
      else if (p.family == AF_INET6)
        {
          stream_get(&p.u.prefix6, s, IPV6_MAX_BYTELEN);
          l += IPV6_MAX_BYTELEN;
        }
      else
        {
          zlog_err("rnh_register: Received unknown family type %d\n",
                   p.family);
          return -1;
        }
      rnh = zebra_add_rnh(&p, zvrf->vrf_id, type);
      if (type == RNH_NEXTHOP_TYPE)
        {
          if (flags && !CHECK_FLAG(rnh->flags, ZEBRA_NHT_CONNECTED))
            SET_FLAG(rnh->flags, ZEBRA_NHT_CONNECTED);
          else if (!flags && CHECK_FLAG(rnh->flags, ZEBRA_NHT_CONNECTED))
            UNSET_FLAG(rnh->flags, ZEBRA_NHT_CONNECTED);
        }
      else if (type == RNH_IMPORT_CHECK_TYPE)
        {
          if (flags && !CHECK_FLAG(rnh->flags, ZEBRA_NHT_EXACT_MATCH))
            SET_FLAG(rnh->flags, ZEBRA_NHT_EXACT_MATCH);
          else if (!flags && CHECK_FLAG(rnh->flags, ZEBRA_NHT_EXACT_MATCH))
            UNSET_FLAG(rnh->flags, ZEBRA_NHT_EXACT_MATCH);
        }

      zebra_add_rnh_client(rnh, client, type, zvrf->vrf_id);
      /* Anything not AF_INET/INET6 has been filtered out above */
      zebra_evaluate_rnh(zvrf->vrf_id, p.family, 1, type, &p);
    }
  return 0;
}

/* Nexthop register */
static int
zserv_rnh_unregister (struct zserv *client, int sock, u_short length,
                      rnh_type_t type, struct zebra_vrf *zvrf)
{
  struct rnh *rnh;
  struct stream *s;
  struct prefix p;
  u_short l = 0;

  if (IS_ZEBRA_DEBUG_NHT)
    zlog_debug("rnh_unregister msg from client %s: length=%d\n",
               zebra_route_string(client->proto), length);

  s = client->ibuf;

  while (l < length)
    {
      (void)stream_getc(s); //Connected or not.  Not used in this function
      p.family = stream_getw(s);
      p.prefixlen = stream_getc(s);
      l += 4;
      if (p.family == AF_INET)
        {
          p.u.prefix4.s_addr = stream_get_ipv4(s);
          l += IPV4_MAX_BYTELEN;
        }
      else if (p.family == AF_INET6)
        {
          stream_get(&p.u.prefix6, s, IPV6_MAX_BYTELEN);
          l += IPV6_MAX_BYTELEN;
        }
      else
        {
          zlog_err("rnh_register: Received unknown family type %d\n",
                   p.family);
          return -1;
        }
      rnh = zebra_lookup_rnh(&p, zvrf->vrf_id, type);
      if (rnh)
        {
          client->nh_dereg_time = quagga_monotime();
          zebra_remove_rnh_client(rnh, client, type);
        }
    }
  return 0;
}

/*
  Modified version of zsend_ipv4_nexthop_lookup():
  Query unicast rib if nexthop is not found on mrib.
  Returns both route metric and protocol distance.
*/
static int
zsend_ipv4_nexthop_lookup_mrib (struct zserv *client, struct in_addr addr, struct rib *rib, struct zebra_vrf *zvrf)
{
  struct stream *s;
  unsigned long nump;
  u_char num;
  struct nexthop *nexthop;

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

  /* Fill in result. */
  zserv_create_header (s, ZEBRA_IPV4_NEXTHOP_LOOKUP_MRIB, zvrf->vrf_id);
  stream_put_in_addr (s, &addr);

  if (rib)
    {
      stream_putc (s, rib->distance);
      stream_putl (s, rib->metric);
      num = 0;
      nump = stream_get_endp(s); /* remember position for nexthop_num */
      stream_putc (s, 0);        /* reserve room for nexthop_num */
      /* Only non-recursive routes are elegible to resolve the nexthop we
       * are looking up. Therefore, we will just iterate over the top
       * chain of nexthops. */
      for (nexthop = rib->nexthop; nexthop; nexthop = nexthop->next)
        if (CHECK_FLAG (nexthop->flags, NEXTHOP_FLAG_FIB))
          {
            stream_putc (s, nexthop->type);
            switch (nexthop->type)
              {
              case ZEBRA_NEXTHOP_IPV4:
                stream_put_in_addr (s, &nexthop->gate.ipv4);
                break;
              case ZEBRA_NEXTHOP_IPV4_IFINDEX:
                stream_put_in_addr (s, &nexthop->gate.ipv4);
                stream_putl (s, nexthop->ifindex);
                break;
              case ZEBRA_NEXTHOP_IFINDEX:
                stream_putl (s, nexthop->ifindex);
                break;
              default:
                /* do nothing */
                break;
              }
            num++;
          }
    
      stream_putc_at (s, nump, num); /* store nexthop_num */
    }
  else
    {
      stream_putc (s, 0); /* distance */
      stream_putl (s, 0); /* metric */
      stream_putc (s, 0); /* nexthop_num */
    }

  stream_putw_at (s, 0, stream_get_endp (s));
  
  return zebra_server_send_message(client);
}

static int
zsend_ipv4_import_lookup (struct zserv *client, struct prefix_ipv4 *p,
    vrf_id_t vrf_id)
{
  struct stream *s;
  struct rib *rib;
  unsigned long nump;
  u_char num;
  struct nexthop *nexthop;

  /* Lookup nexthop. */
  rib = rib_lookup_ipv4 (p, vrf_id);

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

  /* Fill in result. */
  zserv_create_header (s, ZEBRA_IPV4_IMPORT_LOOKUP, vrf_id);
  stream_put_in_addr (s, &p->prefix);

  if (rib)
    {
      stream_putl (s, rib->metric);
      num = 0;
      nump = stream_get_endp(s);
      stream_putc (s, 0);
      for (nexthop = rib->nexthop; nexthop; nexthop = nexthop->next)
        if (CHECK_FLAG(nexthop->flags, NEXTHOP_FLAG_FIB)
            || nexthop_has_fib_child(nexthop))
          {
            stream_putc (s, nexthop->type);
            switch (nexthop->type)
              {
              case ZEBRA_NEXTHOP_IPV4:
                stream_put_in_addr (s, &nexthop->gate.ipv4);
                break;
              case ZEBRA_NEXTHOP_IPV4_IFINDEX:
                stream_put_in_addr (s, &nexthop->gate.ipv4);
                stream_putl (s, nexthop->ifindex);
                break;
              case ZEBRA_NEXTHOP_IFINDEX:
                stream_putl (s, nexthop->ifindex);
                break;
              default:
                /* do nothing */
                break;
              }
            num++;
          }
      stream_putc_at (s, nump, num);
    }
  else
    {
      stream_putl (s, 0);
      stream_putc (s, 0);
    }

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

  return zebra_server_send_message(client);
}

/* Router-id is updated. Send ZEBRA_ROUTER_ID_ADD to client. */
int
zsend_router_id_update (struct zserv *client, struct prefix *p,
    vrf_id_t vrf_id)
{
  struct stream *s;
  int blen;

  /* Check this client need interface information. */
  if (! vrf_bitmap_check (client->ridinfo, vrf_id))
    return 0;

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

  /* Message type. */
  zserv_create_header (s, ZEBRA_ROUTER_ID_UPDATE, vrf_id);

  /* Prefix information. */
  stream_putc (s, p->family);
  blen = prefix_blen (p);
  stream_put (s, &p->u.prefix, blen);
  stream_putc (s, p->prefixlen);

  /* Write packet size. */
  stream_putw_at (s, 0, stream_get_endp (s));

  return zebra_server_send_message(client);
}

/* Register zebra server interface information.  Send current all
   interface and address information. */
static int
zread_interface_add (struct zserv *client, u_short length, struct zebra_vrf *zvrf)
{
  struct listnode *ifnode, *ifnnode;
  vrf_iter_t iter;
  struct interface *ifp;
  struct zebra_vrf *zvrf_iter;

  /* Interface information is needed. */
  vrf_bitmap_set (client->ifinfo, zvrf->vrf_id);

  for (iter = vrf_first (); iter != VRF_ITER_INVALID; iter = vrf_next (iter))
    {
      zvrf_iter = vrf_iter2info (iter);
      for (ALL_LIST_ELEMENTS (vrf_iflist (zvrf_iter->vrf_id), ifnode, ifnnode, ifp))
        {
          /* Skip pseudo interface. */
          if (! CHECK_FLAG (ifp->status, ZEBRA_INTERFACE_ACTIVE))
            continue;

          if (zsend_interface_add (client, ifp) < 0)
            return -1;

          if (zsend_interface_addresses (client, ifp) < 0)
            return -1;
        }
    }
  return 0;
}

/* Unregister zebra server interface information. */
static int
zread_interface_delete (struct zserv *client, u_short length, struct zebra_vrf *zvrf)
{
  vrf_bitmap_unset (client->ifinfo, zvrf->vrf_id);
  return 0;
}

void
zserv_nexthop_num_warn (const char *caller, const struct prefix *p, const unsigned int nexthop_num)
{
  if (nexthop_num > MULTIPATH_NUM)
    {
      char buff[PREFIX2STR_BUFFER];
      prefix2str(p, buff, sizeof (buff));
      zlog_warn("%s: Prefix %s has %d nexthops, but we can only use the first %d",
                caller, buff, nexthop_num, MULTIPATH_NUM);
    }
}

/* This function support multiple nexthop. */
/* 
 * Parse the ZEBRA_IPV4_ROUTE_ADD sent from client. Update rib and
 * add kernel route. 
 */
static int
zread_ipv4_add (struct zserv *client, u_short length, struct zebra_vrf *zvrf)
{
  int i;
  struct rib *rib;
  struct prefix_ipv4 p;
  u_char message;
  struct in_addr nexthop;
  u_char nexthop_num;
  u_char nexthop_type;
  struct stream *s;
  ifindex_t ifindex;
  safi_t safi;
  int ret;

  /* Get input stream.  */
  s = client->ibuf;

  /* Allocate new rib. */
  rib = XCALLOC (MTYPE_RIB, sizeof (struct rib));
  
  /* Type, flags, message. */
  rib->type = stream_getc (s);
  rib->instance = stream_getw (s);
  rib->flags = stream_getc (s);
  message = stream_getc (s); 
  safi = stream_getw (s);
  rib->uptime = time (NULL);

  /* IPv4 prefix. */
  memset (&p, 0, sizeof (struct prefix_ipv4));
  p.family = AF_INET;
  p.prefixlen = stream_getc (s);
  stream_get (&p.prefix, s, PSIZE (p.prefixlen));

  /* VRF ID */
  rib->vrf_id = zvrf->vrf_id;

  /* Nexthop parse. */
  if (CHECK_FLAG (message, ZAPI_MESSAGE_NEXTHOP))
    {
      nexthop_num = stream_getc (s);
      zserv_nexthop_num_warn(__func__, (const struct prefix *)&p, nexthop_num);

      for (i = 0; i < nexthop_num; i++)
        {
          nexthop_type = stream_getc (s);

          switch (nexthop_type)
            {
            case ZEBRA_NEXTHOP_IFINDEX:
              ifindex = stream_getl (s);
              rib_nexthop_ifindex_add (rib, ifindex);
              break;
            case ZEBRA_NEXTHOP_IPV4:
              nexthop.s_addr = stream_get_ipv4 (s);
              rib_nexthop_ipv4_add (rib, &nexthop, NULL);
              break;
            case ZEBRA_NEXTHOP_IPV4_IFINDEX:
              nexthop.s_addr = stream_get_ipv4 (s);
              ifindex = stream_getl (s);
              rib_nexthop_ipv4_ifindex_add (rib, &nexthop, NULL, ifindex);
              break;
            case ZEBRA_NEXTHOP_IPV6:
              stream_forward_getp (s, IPV6_MAX_BYTELEN);
              break;
            case ZEBRA_NEXTHOP_BLACKHOLE:
              rib_nexthop_blackhole_add (rib);
              break;
            }
        }
    }

  /* Distance. */
  if (CHECK_FLAG (message, ZAPI_MESSAGE_DISTANCE))
    rib->distance = stream_getc (s);

  /* Metric. */
  if (CHECK_FLAG (message, ZAPI_MESSAGE_METRIC))
    rib->metric = stream_getl (s);
    
  /* Tag */
  if (CHECK_FLAG (message, ZAPI_MESSAGE_TAG))
    rib->tag = stream_getw (s);
  else
    rib->tag = 0;

  /* Table */
  rib->table = zvrf->table_id;

  ret = rib_add_ipv4_multipath (&p, rib, safi);

  /* Stats */
  if (ret > 0)
    client->v4_route_add_cnt++;
  else if (ret < 0)
    client->v4_route_upd8_cnt++;
  return 0;
}

/* Zebra server IPv4 prefix delete function. */
static int
zread_ipv4_delete (struct zserv *client, u_short length, struct zebra_vrf *zvrf)
{
  int i;
  struct stream *s;
  struct zapi_ipv4 api;
  struct in_addr nexthop, *nexthop_p;
  unsigned long ifindex;
  struct prefix_ipv4 p;
  u_char nexthop_num;
  u_char nexthop_type;
  u_int32_t table_id;

  s = client->ibuf;
  ifindex = 0;
  nexthop.s_addr = 0;
  nexthop_p = NULL;

  /* Type, flags, message. */
  api.type = stream_getc (s);
  api.instance = stream_getw (s);
  api.flags = stream_getc (s);
  api.message = stream_getc (s);
  api.safi = stream_getw (s);

  /* IPv4 prefix. */
  memset (&p, 0, sizeof (struct prefix_ipv4));
  p.family = AF_INET;
  p.prefixlen = stream_getc (s);
  stream_get (&p.prefix, s, PSIZE (p.prefixlen));

  /* Nexthop, ifindex, distance, metric. */
  if (CHECK_FLAG (api.message, ZAPI_MESSAGE_NEXTHOP))
    {
      nexthop_num = stream_getc (s);

      for (i = 0; i < nexthop_num; i++)
        {
          nexthop_type = stream_getc (s);

          switch (nexthop_type)
            {
            case ZEBRA_NEXTHOP_IFINDEX:
              ifindex = stream_getl (s);
              break;
            case ZEBRA_NEXTHOP_IPV4:
              nexthop.s_addr = stream_get_ipv4 (s);
              nexthop_p = &nexthop;
              break;
            case ZEBRA_NEXTHOP_IPV4_IFINDEX:
              nexthop.s_addr = stream_get_ipv4 (s);
              nexthop_p = &nexthop;
              ifindex = stream_getl (s);
              break;
            case ZEBRA_NEXTHOP_IPV6:
              stream_forward_getp (s, IPV6_MAX_BYTELEN);
              break;
            }
        }
    }

  /* Distance. */
  if (CHECK_FLAG (api.message, ZAPI_MESSAGE_DISTANCE))
    api.distance = stream_getc (s);
  else
    api.distance = 0;

  /* Metric. */
  if (CHECK_FLAG (api.message, ZAPI_MESSAGE_METRIC))
    api.metric = stream_getl (s);
  else
    api.metric = 0;
    
  /* tag */
  if (CHECK_FLAG (api.message, ZAPI_MESSAGE_TAG))
    api.tag = stream_getw (s);
  else
    api.tag = 0;

  table_id = zvrf->table_id;

  rib_delete_ipv4 (api.type, api.instance, api.flags, &p, nexthop_p, ifindex,
                   zvrf->vrf_id, table_id, api.safi);
  client->v4_route_del_cnt++;
  return 0;
}

/* Nexthop lookup for IPv4. */
static int
zread_ipv4_nexthop_lookup (struct zserv *client, u_short length,
                           struct zebra_vrf *zvrf)
{
  struct in_addr addr;
  char buf[BUFSIZ];

  addr.s_addr = stream_get_ipv4 (client->ibuf);
  if (IS_ZEBRA_DEBUG_PACKET && IS_ZEBRA_DEBUG_RECV)
    zlog_debug("%s: looking up %s", __func__,
               inet_ntop (AF_INET, &addr, buf, BUFSIZ));
  return zsend_ipv4_nexthop_lookup (client, addr, zvrf->vrf_id);
}

/* MRIB Nexthop lookup for IPv4. */
static int
zread_ipv4_nexthop_lookup_mrib (struct zserv *client, u_short length, struct zebra_vrf *zvrf)
{
  struct in_addr addr;
  struct rib *rib;

  addr.s_addr = stream_get_ipv4 (client->ibuf);
  rib = rib_match_ipv4_multicast (addr, NULL);
  return zsend_ipv4_nexthop_lookup_mrib (client, addr, rib, zvrf);
}

/* Nexthop lookup for IPv4. */
static int
zread_ipv4_import_lookup (struct zserv *client, u_short length,
                          struct zebra_vrf *zvrf)
{
  struct prefix_ipv4 p;

  p.family = AF_INET;
  p.prefixlen = stream_getc (client->ibuf);
  p.prefix.s_addr = stream_get_ipv4 (client->ibuf);

  return zsend_ipv4_import_lookup (client, &p, zvrf->vrf_id);
}

/* Zebra server IPv6 prefix add function. */
static int
zread_ipv4_route_ipv6_nexthop_add (struct zserv *client, u_short length, struct zebra_vrf *zvrf)
{
  int i;
  struct stream *s;
  struct in6_addr nexthop;
  struct rib *rib;
  u_char message;
  u_char nexthop_num;
  u_char nexthop_type;
  unsigned long ifindex;
  struct prefix_ipv4 p;
  safi_t safi;
  static struct in6_addr nexthops[MULTIPATH_NUM];
  static unsigned int ifindices[MULTIPATH_NUM];
  int ret;

  /* Get input stream.  */
  s = client->ibuf;

  ifindex = 0;
  memset (&nexthop, 0, sizeof (struct in6_addr));

  /* Allocate new rib. */
  rib = XCALLOC (MTYPE_RIB, sizeof (struct rib));

  /* Type, flags, message. */
  rib->type = stream_getc (s);
  rib->instance = stream_getw (s);
  rib->flags = stream_getc (s);
  message = stream_getc (s);
  safi = stream_getw (s);
  rib->uptime = time (NULL);

  /* IPv4 prefix. */
  memset (&p, 0, sizeof (struct prefix_ipv4));
  p.family = AF_INET;
  p.prefixlen = stream_getc (s);
  stream_get (&p.prefix, s, PSIZE (p.prefixlen));

  /* VRF ID */
  rib->vrf_id = zvrf->vrf_id;

  /* We need to give nh-addr, nh-ifindex with the same next-hop object
   * to the rib to ensure that IPv6 multipathing works; need to coalesce
   * these. Clients should send the same number of paired set of
   * next-hop-addr/next-hop-ifindices. */
  if (CHECK_FLAG (message, ZAPI_MESSAGE_NEXTHOP))
    {
      int nh_count = 0;
      int if_count = 0;
      int max_nh_if = 0;

      nexthop_num = stream_getc (s);
      zserv_nexthop_num_warn(__func__, (const struct prefix *)&p, nexthop_num);
      for (i = 0; i < nexthop_num; i++)
        {
          nexthop_type = stream_getc (s);

          switch (nexthop_type)
            {
            case ZEBRA_NEXTHOP_IPV6:
              stream_get (&nexthop, s, 16);
              if (nh_count < MULTIPATH_NUM) {
                nexthops[nh_count++] = nexthop;
              }
              break;
            case ZEBRA_NEXTHOP_IFINDEX:
              if (if_count < MULTIPATH_NUM) {
                ifindices[if_count++] = stream_getl (s);
              }
              break;
            case ZEBRA_NEXTHOP_BLACKHOLE:
              rib_nexthop_blackhole_add (rib);
              break;
            }
        }

      max_nh_if = (nh_count > if_count) ? nh_count : if_count;
      for (i = 0; i < max_nh_if; i++)
        {
          if ((i < nh_count) && !IN6_IS_ADDR_UNSPECIFIED (&nexthops[i])) {
            if ((i < if_count) && ifindices[i]) {
              rib_nexthop_ipv6_ifindex_add (rib, &nexthops[i], ifindices[i]);
            }
            else {
              rib_nexthop_ipv6_add (rib, &nexthops[i]);
            }
          }
          else {
            if ((i < if_count) && ifindices[i]) {
              rib_nexthop_ifindex_add (rib, ifindices[i]);
            }
          }
        }
    }

  /* Distance. */
  if (CHECK_FLAG (message, ZAPI_MESSAGE_DISTANCE))
    rib->distance = stream_getc (s);

  /* Metric. */
  if (CHECK_FLAG (message, ZAPI_MESSAGE_METRIC))
    rib->metric = stream_getl (s);

  /* Tag */
  if (CHECK_FLAG (message, ZAPI_MESSAGE_TAG))
    rib->tag = stream_getw (s);
  else
    rib->tag = 0;

  /* Table */
  rib->table = zvrf->table_id;

  ret = rib_add_ipv6_multipath ((struct prefix *)&p, rib, safi, ifindex);
  /* Stats */
  if (ret > 0)
    client->v4_route_add_cnt++;
  else if (ret < 0)
    client->v4_route_upd8_cnt++;

  return 0;
}

static int
zread_ipv6_add (struct zserv *client, u_short length, struct zebra_vrf *zvrf)
{
  int i;
  struct stream *s;
  struct in6_addr nexthop;
  struct rib *rib;
  u_char message;
  u_char nexthop_num;
  u_char nexthop_type;
  unsigned long ifindex;
  struct prefix_ipv6 p;
  safi_t safi;
  static struct in6_addr nexthops[MULTIPATH_NUM];
  static unsigned int ifindices[MULTIPATH_NUM];
  int ret;

  /* Get input stream.  */
  s = client->ibuf;

  ifindex = 0;
  memset (&nexthop, 0, sizeof (struct in6_addr));

  /* Allocate new rib. */
  rib = XCALLOC (MTYPE_RIB, sizeof (struct rib));

  /* Type, flags, message. */
  rib->type = stream_getc (s);
  rib->instance = stream_getw (s);
  rib->flags = stream_getc (s);
  message = stream_getc (s);
  safi = stream_getw (s);
  rib->uptime = time (NULL);

  /* IPv6 prefix. */
  memset (&p, 0, sizeof (struct prefix_ipv6));
  p.family = AF_INET6;
  p.prefixlen = stream_getc (s);
  stream_get (&p.prefix, s, PSIZE (p.prefixlen));

  /* We need to give nh-addr, nh-ifindex with the same next-hop object
   * to the rib to ensure that IPv6 multipathing works; need to coalesce
   * these. Clients should send the same number of paired set of
   * next-hop-addr/next-hop-ifindices. */
  if (CHECK_FLAG (message, ZAPI_MESSAGE_NEXTHOP))
    {
      int nh_count = 0;
      int if_count = 0;
      int max_nh_if = 0;

      nexthop_num = stream_getc (s);
      zserv_nexthop_num_warn(__func__, (const struct prefix *)&p, nexthop_num);
      for (i = 0; i < nexthop_num; i++) 
        {
          nexthop_type = stream_getc (s);

          switch (nexthop_type)
            {
            case ZEBRA_NEXTHOP_IPV6:
              stream_get (&nexthop, s, 16);
              if (nh_count < MULTIPATH_NUM) {
                nexthops[nh_count++] = nexthop;
              }
              break;
            case ZEBRA_NEXTHOP_IFINDEX:
              if (if_count < MULTIPATH_NUM) {
                ifindices[if_count++] = stream_getl (s);
              }
              break;
            case ZEBRA_NEXTHOP_BLACKHOLE:
              rib_nexthop_blackhole_add (rib);
              break;
            }
        }

      max_nh_if = (nh_count > if_count) ? nh_count : if_count;
      for (i = 0; i < max_nh_if; i++)
        {
          if ((i < nh_count) && !IN6_IS_ADDR_UNSPECIFIED (&nexthops[i])) {
            if ((i < if_count) && ifindices[i])
              rib_nexthop_ipv6_ifindex_add (rib, &nexthops[i], ifindices[i]);
            else
              rib_nexthop_ipv6_add (rib, &nexthops[i]);
          }
          else {
            if ((i < if_count) && ifindices[i])
              rib_nexthop_ifindex_add (rib, ifindices[i]);
          }
        }
    }

  /* Distance. */
  if (CHECK_FLAG (message, ZAPI_MESSAGE_DISTANCE))
    rib->distance = stream_getc (s);

  /* Metric. */
  if (CHECK_FLAG (message, ZAPI_MESSAGE_METRIC))
    rib->metric = stream_getl (s);
    
  /* Tag */
  if (CHECK_FLAG (message, ZAPI_MESSAGE_TAG))
    rib->tag = stream_getw (s);
  else
    rib->tag = 0;

  /* VRF ID */
  rib->vrf_id = zvrf->vrf_id;
  rib->table = zvrf->table_id;

  ret = rib_add_ipv6_multipath ((struct prefix *)&p, rib, safi, ifindex);
  /* Stats */
  if (ret > 0)
    client->v6_route_add_cnt++;
  else if (ret < 0)
    client->v6_route_upd8_cnt++;

  return 0;
}

/* Zebra server IPv6 prefix delete function. */
static int
zread_ipv6_delete (struct zserv *client, u_short length, struct zebra_vrf *zvrf)
{
  int i;
  struct stream *s;
  struct zapi_ipv6 api;
  struct in6_addr nexthop;
  unsigned long ifindex;
  struct prefix_ipv6 p;
  
  s = client->ibuf;
  ifindex = 0;
  memset (&nexthop, 0, sizeof (struct in6_addr));

  /* Type, flags, message. */
  api.type = stream_getc (s);
  api.instance = stream_getw (s);
  api.flags = stream_getc (s);
  api.message = stream_getc (s);
  api.safi = stream_getw (s);

  /* IPv4 prefix. */
  memset (&p, 0, sizeof (struct prefix_ipv6));
  p.family = AF_INET6;
  p.prefixlen = stream_getc (s);
  stream_get (&p.prefix, s, PSIZE (p.prefixlen));

  /* Nexthop, ifindex, distance, metric. */
  if (CHECK_FLAG (api.message, ZAPI_MESSAGE_NEXTHOP))
    {
      u_char nexthop_type;

      api.nexthop_num = stream_getc (s);
      for (i = 0; i < api.nexthop_num; i++)
        {
          nexthop_type = stream_getc (s);

          switch (nexthop_type)
            {
            case ZEBRA_NEXTHOP_IPV6:
              stream_get (&nexthop, s, 16);
              break;
            case ZEBRA_NEXTHOP_IFINDEX:
              ifindex = stream_getl (s);
              break;
            }
        }
    }

  /* Distance. */
  if (CHECK_FLAG (api.message, ZAPI_MESSAGE_DISTANCE))
    api.distance = stream_getc (s);
  else
    api.distance = 0;

  /* Metric. */
  if (CHECK_FLAG (api.message, ZAPI_MESSAGE_METRIC))
    api.metric = stream_getl (s);
  else
    api.metric = 0;
    
  /* tag */
  if (CHECK_FLAG (api.message, ZAPI_MESSAGE_TAG))
    api.tag = stream_getw (s);
  else
    api.tag = 0;

  if (IN6_IS_ADDR_UNSPECIFIED (&nexthop))
    rib_delete_ipv6 (api.type, api.instance, api.flags, &p, NULL, ifindex,
                     zvrf->vrf_id, client->rtm_table, api.safi);
  else
    rib_delete_ipv6 (api.type, api.instance, api.flags, &p, &nexthop, ifindex,
                     zvrf->vrf_id, client->rtm_table, api.safi);

  client->v6_route_del_cnt++;
  return 0;
}

static int
zread_ipv6_nexthop_lookup (struct zserv *client, u_short length,
                           struct zebra_vrf *zvrf)
{
  struct in6_addr addr;
  char buf[BUFSIZ];

  stream_get (&addr, client->ibuf, 16);
  if (IS_ZEBRA_DEBUG_PACKET && IS_ZEBRA_DEBUG_RECV)
    zlog_debug("%s: looking up %s", __func__,
               inet_ntop (AF_INET6, &addr, buf, BUFSIZ));

  return zsend_ipv6_nexthop_lookup (client, &addr, zvrf->vrf_id);
}

/* Register zebra server router-id information.  Send current router-id */
static int
zread_router_id_add (struct zserv *client, u_short length, struct zebra_vrf *zvrf)
{
  struct prefix p;

  /* Router-id information is needed. */
  vrf_bitmap_set (client->ridinfo, zvrf->vrf_id);

  router_id_get (&p, zvrf->vrf_id);

  return zsend_router_id_update (client, &p, zvrf->vrf_id);
}

/* Unregister zebra server router-id information. */
static int
zread_router_id_delete (struct zserv *client, u_short length, struct zebra_vrf *zvrf)
{
  vrf_bitmap_unset (client->ridinfo, zvrf->vrf_id);
  return 0;
}

/* Tie up route-type and client->sock */
static void
zread_hello (struct zserv *client)
{
  /* type of protocol (lib/zebra.h) */
  u_char proto;
  u_short instance;

  proto = stream_getc (client->ibuf);
  instance = stream_getw (client->ibuf);

  /* accept only dynamic routing protocols */
  if ((proto < ZEBRA_ROUTE_MAX)
  &&  (proto > ZEBRA_ROUTE_STATIC))
    {
      zlog_notice ("client %d says hello and bids fair to announce only %s routes",
                    client->sock, zebra_route_string(proto));
      if (instance)
        zlog_notice ("client protocol instance %d", instance);

      client->proto = proto;
      client->instance = instance;
    }
}

/* Unregister all information in a VRF. */
static int
zread_vrf_unregister (struct zserv *client, u_short length, struct zebra_vrf *zvrf)
{
  int i;
  afi_t afi;

  for (afi = AFI_IP; afi < AFI_MAX; afi++)
    for (i = 0; i < ZEBRA_ROUTE_MAX; i++)
      vrf_bitmap_unset (client->redist[afi][i], zvrf->vrf_id);
  vrf_bitmap_unset (client->redist_default, zvrf->vrf_id);
  vrf_bitmap_unset (client->ifinfo, zvrf->vrf_id);
  vrf_bitmap_unset (client->ridinfo, zvrf->vrf_id);

  return 0;
}

/* Cleanup registered nexthops (across VRFs) upon client disconnect. */
static void
zebra_client_close_cleanup_rnh (struct zserv *client)
{
  vrf_iter_t iter;
  struct zebra_vrf *zvrf;

  for (iter = vrf_first (); iter != VRF_ITER_INVALID; iter = vrf_next (iter))
    {
      if ((zvrf = vrf_iter2info (iter)) != NULL)
        {
          zebra_cleanup_rnh_client(zvrf->vrf_id, AF_INET, client, RNH_NEXTHOP_TYPE);
          zebra_cleanup_rnh_client(zvrf->vrf_id, AF_INET6, client, RNH_NEXTHOP_TYPE);
          zebra_cleanup_rnh_client(zvrf->vrf_id, AF_INET, client, RNH_IMPORT_CHECK_TYPE);
          zebra_cleanup_rnh_client(zvrf->vrf_id, AF_INET6, client, RNH_IMPORT_CHECK_TYPE);
        }
    }
}

/* Close zebra client. */
static void
zebra_client_close (struct zserv *client)
{
  /* Send client de-registration to BFD */
  zebra_ptm_bfd_client_deregister(client->proto);

  /* Cleanup any registered nexthops - across all VRFs. */
  zebra_client_close_cleanup_rnh (client);

  /* Close file descriptor. */
  if (client->sock)
    {
      unsigned long nroutes;

      close (client->sock);
      nroutes = rib_score_proto (client->proto, client->instance);
      zlog_notice ("client %d disconnected. %lu %s routes removed from the rib",
                   client->sock, nroutes, zebra_route_string (client->proto));
      client->sock = -1;
    }

  /* Free stream buffers. */
  if (client->ibuf)
    stream_free (client->ibuf);
  if (client->obuf)
    stream_free (client->obuf);
  if (client->wb)
    buffer_free(client->wb);

  /* Release threads. */
  if (client->t_read)
    thread_cancel (client->t_read);
  if (client->t_write)
    thread_cancel (client->t_write);
  if (client->t_suicide)
    thread_cancel (client->t_suicide);

  /* Free client structure. */
  listnode_delete (zebrad.client_list, client);
  XFREE (MTYPE_TMP, client);
}

/* Make new client. */
static void
zebra_client_create (int sock)
{
  struct zserv *client;
  int i;
  afi_t afi;

  client = XCALLOC (MTYPE_TMP, sizeof (struct zserv));

  /* Make client input/output buffer. */
  client->sock = sock;
  client->ibuf = stream_new (ZEBRA_MAX_PACKET_SIZ);
  client->obuf = stream_new (ZEBRA_MAX_PACKET_SIZ);
  client->wb = buffer_new(0);

  /* Set table number. */
  client->rtm_table = zebrad.rtm_table_default;

  client->connect_time = quagga_monotime();
  /* Initialize flags */
  for (afi = AFI_IP; afi < AFI_MAX; afi++)
    for (i = 0; i < ZEBRA_ROUTE_MAX; i++)
      client->redist[afi][i] = vrf_bitmap_init ();
  client->redist_default = vrf_bitmap_init ();
  client->ifinfo = vrf_bitmap_init ();
  client->ridinfo = vrf_bitmap_init ();

  /* Add this client to linked list. */
  listnode_add (zebrad.client_list, client);
  
  /* Make new read thread. */
  zebra_event (ZEBRA_READ, sock, client);

  zebra_vrf_update_all (client);
}

/* Handler of zebra service request. */
static int
zebra_client_read (struct thread *thread)
{
  int sock;
  struct zserv *client;
  size_t already;
  uint16_t length, command;
  uint8_t marker, version;
  vrf_id_t vrf_id;
  struct zebra_vrf *zvrf;

  /* Get thread data.  Reset reading thread because I'm running. */
  sock = THREAD_FD (thread);
  client = THREAD_ARG (thread);
  client->t_read = NULL;

  if (client->t_suicide)
    {
      zebra_client_close(client);
      return -1;
    }

  /* Read length and command (if we don't have it already). */
  if ((already = stream_get_endp(client->ibuf)) < ZEBRA_HEADER_SIZE)
    {
      ssize_t nbyte;
      if (((nbyte = stream_read_try (client->ibuf, sock,
                                     ZEBRA_HEADER_SIZE-already)) == 0) ||
          (nbyte == -1))
        {
          if (IS_ZEBRA_DEBUG_EVENT)
            zlog_debug ("connection closed socket [%d]", sock);
          zebra_client_close (client);
          return -1;
        }
      if (nbyte != (ssize_t)(ZEBRA_HEADER_SIZE-already))
        {
          /* Try again later. */
          zebra_event (ZEBRA_READ, sock, client);
          return 0;
        }
      already = ZEBRA_HEADER_SIZE;
    }

  /* Reset to read from the beginning of the incoming packet. */
  stream_set_getp(client->ibuf, 0);

  /* Fetch header values */
  length = stream_getw (client->ibuf);
  marker = stream_getc (client->ibuf);
  version = stream_getc (client->ibuf);
  vrf_id = stream_getw (client->ibuf);
  command = stream_getw (client->ibuf);

  if (marker != ZEBRA_HEADER_MARKER || version != ZSERV_VERSION)
    {
      zlog_err("%s: socket %d version mismatch, marker %d, version %d",
               __func__, sock, marker, version);
      zebra_client_close (client);
      return -1;
    }
  if (length < ZEBRA_HEADER_SIZE) 
    {
      zlog_warn("%s: socket %d message length %u is less than header size %d",
                __func__, sock, length, ZEBRA_HEADER_SIZE);
      zebra_client_close (client);
      return -1;
    }
  if (length > STREAM_SIZE(client->ibuf))
    {
      zlog_warn("%s: socket %d message length %u exceeds buffer size %lu",
                __func__, sock, length, (u_long)STREAM_SIZE(client->ibuf));
      zebra_client_close (client);
      return -1;
    }

  /* Read rest of data. */
  if (already < length)
    {
      ssize_t nbyte;
      if (((nbyte = stream_read_try (client->ibuf, sock,
                                     length-already)) == 0) ||
          (nbyte == -1))
        {
          if (IS_ZEBRA_DEBUG_EVENT)
            zlog_debug ("connection closed [%d] when reading zebra data", sock);
          zebra_client_close (client);
          return -1;
        }
      if (nbyte != (ssize_t)(length-already))
        {
          /* Try again later. */
          zebra_event (ZEBRA_READ, sock, client);
          return 0;
        }
    }

  length -= ZEBRA_HEADER_SIZE;

  /* Debug packet information. */
  if (IS_ZEBRA_DEBUG_EVENT)
    zlog_debug ("zebra message comes from socket [%d]", sock);

  if (IS_ZEBRA_DEBUG_PACKET && IS_ZEBRA_DEBUG_RECV)
    zlog_debug ("zebra message received [%s] %d in VRF %u",
               zserv_command_string (command), length, vrf_id);

  client->last_read_time = quagga_monotime();
  client->last_read_cmd = command;

  zvrf = zebra_vrf_lookup (vrf_id);
  if (!zvrf)
    {
      if (IS_ZEBRA_DEBUG_PACKET && IS_ZEBRA_DEBUG_RECV)
        zlog_debug ("zebra received unknown VRF[%u]", vrf_id);
      goto zclient_read_out;
    }

  switch (command) 
    {
    case ZEBRA_ROUTER_ID_ADD:
      zread_router_id_add (client, length, zvrf);
      break;
    case ZEBRA_ROUTER_ID_DELETE:
      zread_router_id_delete (client, length, zvrf);
      break;
    case ZEBRA_INTERFACE_ADD:
      zread_interface_add (client, length, zvrf);
      break;
    case ZEBRA_INTERFACE_DELETE:
      zread_interface_delete (client, length, zvrf);
      break;
    case ZEBRA_IPV4_ROUTE_ADD:
      zread_ipv4_add (client, length, zvrf);
      break;
    case ZEBRA_IPV4_ROUTE_DELETE:
      zread_ipv4_delete (client, length, zvrf);
      break;
    case ZEBRA_IPV4_ROUTE_IPV6_NEXTHOP_ADD:
      zread_ipv4_route_ipv6_nexthop_add (client, length, zvrf);
      break;
    case ZEBRA_IPV6_ROUTE_ADD:
      zread_ipv6_add (client, length, zvrf);
      break;
    case ZEBRA_IPV6_ROUTE_DELETE:
      zread_ipv6_delete (client, length, zvrf);
      break;
    case ZEBRA_REDISTRIBUTE_ADD:
      zebra_redistribute_add (command, client, length, zvrf);
      break;
    case ZEBRA_REDISTRIBUTE_DELETE:
      zebra_redistribute_delete (command, client, length, zvrf);
      break;
    case ZEBRA_REDISTRIBUTE_DEFAULT_ADD:
      zebra_redistribute_default_add (command, client, length, zvrf);
      break;
    case ZEBRA_REDISTRIBUTE_DEFAULT_DELETE:
      zebra_redistribute_default_delete (command, client, length, zvrf);
      break;
    case ZEBRA_IPV4_NEXTHOP_LOOKUP:
      zread_ipv4_nexthop_lookup (client, length, zvrf);
      break;
    case ZEBRA_IPV4_NEXTHOP_LOOKUP_MRIB:
      zread_ipv4_nexthop_lookup_mrib (client, length, zvrf);
      break;
    case ZEBRA_IPV6_NEXTHOP_LOOKUP:
      zread_ipv6_nexthop_lookup (client, length, zvrf);
      break;
    case ZEBRA_IPV4_IMPORT_LOOKUP:
      zread_ipv4_import_lookup (client, length, zvrf);
      break;
    case ZEBRA_HELLO:
      zread_hello (client);
      break;
    case ZEBRA_NEXTHOP_REGISTER:
      zserv_rnh_register(client, sock, length, RNH_NEXTHOP_TYPE, zvrf);
      break;
    case ZEBRA_NEXTHOP_UNREGISTER:
      zserv_rnh_unregister(client, sock, length, RNH_NEXTHOP_TYPE, zvrf);
      break;
    case ZEBRA_IMPORT_ROUTE_REGISTER:
      zserv_rnh_register(client, sock, length, RNH_IMPORT_CHECK_TYPE, zvrf);
      break;
    case ZEBRA_IMPORT_ROUTE_UNREGISTER:
      zserv_rnh_unregister(client, sock, length, RNH_IMPORT_CHECK_TYPE, zvrf);
      break;
    case ZEBRA_BFD_DEST_UPDATE:
    case ZEBRA_BFD_DEST_REGISTER:
      zebra_ptm_bfd_dst_register(client, sock, length, command, zvrf);
      break;
    case ZEBRA_BFD_DEST_DEREGISTER:
      zebra_ptm_bfd_dst_deregister(client, sock, length, zvrf);
      break;
    case ZEBRA_VRF_UNREGISTER:
      zread_vrf_unregister (client, length, zvrf);
      break;
    case ZEBRA_BFD_CLIENT_REGISTER:
      zebra_ptm_bfd_client_register(client, sock, length);
      break;
    case ZEBRA_INTERFACE_ENABLE_RADV:
      zebra_interface_radv_set (client, sock, length, zvrf, 1);
      break;
    case ZEBRA_INTERFACE_DISABLE_RADV:
      zebra_interface_radv_set (client, sock, length, zvrf, 0);
      break;
    default:
      zlog_info ("Zebra received unknown command %d", command);
      break;
    }

  if (client->t_suicide)
    {
      /* No need to wait for thread callback, just kill immediately. */
      zebra_client_close(client);
      return -1;
    }

 zclient_read_out:
  stream_reset (client->ibuf);
  zebra_event (ZEBRA_READ, sock, client);
  return 0;
}


/* Accept code of zebra server socket. */
static int
zebra_accept (struct thread *thread)
{
  int accept_sock;
  int client_sock;
  struct sockaddr_in client;
  socklen_t len;

  accept_sock = THREAD_FD (thread);

  /* Reregister myself. */
  zebra_event (ZEBRA_SERV, accept_sock, NULL);

  len = sizeof (struct sockaddr_in);
  client_sock = accept (accept_sock, (struct sockaddr *) &client, &len);

  if (client_sock < 0)
    {
      zlog_warn ("Can't accept zebra socket: %s", safe_strerror (errno));
      return -1;
    }

  /* Make client socket non-blocking.  */
  set_nonblocking(client_sock);
  
  /* Create new zebra client. */
  zebra_client_create (client_sock);

  return 0;
}

#ifdef HAVE_TCP_ZEBRA
/* Make zebra's server socket. */
static void
zebra_serv ()
{
  int ret;
  int accept_sock;
  struct sockaddr_in addr;

  accept_sock = socket (AF_INET, SOCK_STREAM, 0);

  if (accept_sock < 0) 
    {
      zlog_warn ("Can't create zserv stream socket: %s", 
                 safe_strerror (errno));
      zlog_warn ("zebra can't provice full functionality due to above error");
      return;
    }

  memset (&addr, 0, sizeof (struct sockaddr_in));
  addr.sin_family = AF_INET;
  addr.sin_port = htons (ZEBRA_PORT);
#ifdef HAVE_STRUCT_SOCKADDR_IN_SIN_LEN
  addr.sin_len = sizeof (struct sockaddr_in);
#endif /* HAVE_STRUCT_SOCKADDR_IN_SIN_LEN */
  addr.sin_addr.s_addr = htonl (INADDR_LOOPBACK);

  sockopt_reuseaddr (accept_sock);
  sockopt_reuseport (accept_sock);

  if ( zserv_privs.change(ZPRIVS_RAISE) )
    zlog (NULL, LOG_ERR, "Can't raise privileges");
    
  ret  = bind (accept_sock, (struct sockaddr *)&addr, 
               sizeof (struct sockaddr_in));
  if (ret < 0)
    {
      zlog_warn ("Can't bind to stream socket: %s", 
                 safe_strerror (errno));
      zlog_warn ("zebra can't provice full functionality due to above error");
      close (accept_sock);      /* Avoid sd leak. */
      return;
    }
    
  if ( zserv_privs.change(ZPRIVS_LOWER) )
    zlog (NULL, LOG_ERR, "Can't lower privileges");

  ret = listen (accept_sock, 1);
  if (ret < 0)
    {
      zlog_warn ("Can't listen to stream socket: %s", 
                 safe_strerror (errno));
      zlog_warn ("zebra can't provice full functionality due to above error");
      close (accept_sock);      /* Avoid sd leak. */
      return;
    }

  zebra_event (ZEBRA_SERV, accept_sock, NULL);
}
#else /* HAVE_TCP_ZEBRA */

/* For sockaddr_un. */
#include <sys/un.h>

/* zebra server UNIX domain socket. */
static void
zebra_serv_un (const char *path)
{
  int ret;
  int sock, len;
  struct sockaddr_un serv;
  mode_t old_mask;

  /* First of all, unlink existing socket */
  unlink (path);

  /* Set umask */
  old_mask = umask (0077);

  /* Make UNIX domain socket. */
  sock = socket (AF_UNIX, SOCK_STREAM, 0);
  if (sock < 0)
    {
      zlog_warn ("Can't create zserv unix socket: %s", 
                 safe_strerror (errno));
      zlog_warn ("zebra can't provide full functionality due to above error");
      return;
    }

  /* Make server socket. */
  memset (&serv, 0, sizeof (struct sockaddr_un));
  serv.sun_family = AF_UNIX;
  strncpy (serv.sun_path, path, strlen (path));
#ifdef HAVE_STRUCT_SOCKADDR_UN_SUN_LEN
  len = serv.sun_len = SUN_LEN(&serv);
#else
  len = sizeof (serv.sun_family) + strlen (serv.sun_path);
#endif /* HAVE_STRUCT_SOCKADDR_UN_SUN_LEN */

  ret = bind (sock, (struct sockaddr *) &serv, len);
  if (ret < 0)
    {
      zlog_warn ("Can't bind to unix socket %s: %s", 
                 path, safe_strerror (errno));
      zlog_warn ("zebra can't provide full functionality due to above error");
      close (sock);
      return;
    }

  ret = listen (sock, 5);
  if (ret < 0)
    {
      zlog_warn ("Can't listen to unix socket %s: %s", 
                 path, safe_strerror (errno));
      zlog_warn ("zebra can't provide full functionality due to above error");
      close (sock);
      return;
    }

  umask (old_mask);

  zebra_event (ZEBRA_SERV, sock, NULL);
}
#endif /* HAVE_TCP_ZEBRA */


static void
zebra_event (enum event event, int sock, struct zserv *client)
{
  switch (event)
    {
    case ZEBRA_SERV:
      thread_add_read (zebrad.master, zebra_accept, client, sock);
      break;
    case ZEBRA_READ:
      client->t_read = 
        thread_add_read (zebrad.master, zebra_client_read, client, sock);
      break;
    case ZEBRA_WRITE:
      /**/
      break;
    }
}

#define ZEBRA_TIME_BUF 32
static char *
zserv_time_buf(time_t *time1, char *buf, int buflen)
{
  struct tm *tm;
  time_t now;

  assert (buf != NULL);
  assert (buflen >= ZEBRA_TIME_BUF);
  assert (time1 != NULL);

  if (!*time1)
    {
      snprintf(buf, buflen, "never   ");
      return (buf);
    }

  now = quagga_monotime();
  now -= *time1;
  tm = gmtime(&now);

  /* Making formatted timer strings. */
#define ONE_DAY_SECOND 60*60*24
#define ONE_WEEK_SECOND 60*60*24*7

  if (now < ONE_DAY_SECOND)
    snprintf (buf, buflen, "%02d:%02d:%02d",
              tm->tm_hour, tm->tm_min, tm->tm_sec);
  else if (now < ONE_WEEK_SECOND)
    snprintf (buf, buflen, "%dd%02dh%02dm",
              tm->tm_yday, tm->tm_hour, tm->tm_min);
  else
    snprintf (buf, buflen, "%02dw%dd%02dh",
              tm->tm_yday/7, tm->tm_yday - ((tm->tm_yday/7) * 7), tm->tm_hour);
  return buf;
}

static void
zebra_show_client_detail (struct vty *vty, struct zserv *client)
{
  char cbuf[ZEBRA_TIME_BUF], rbuf[ZEBRA_TIME_BUF];
  char wbuf[ZEBRA_TIME_BUF], nhbuf[ZEBRA_TIME_BUF], mbuf[ZEBRA_TIME_BUF];

  vty_out (vty, "Client: %s", zebra_route_string(client->proto));
  if (client->instance)
    vty_out (vty, " Instance: %d", client->instance);
  vty_out (vty, "%s", VTY_NEWLINE);

  vty_out (vty, "------------------------ %s", VTY_NEWLINE);
  vty_out (vty, "FD: %d %s", client->sock, VTY_NEWLINE);
  vty_out (vty, "Route Table ID: %d %s", client->rtm_table, VTY_NEWLINE);

  vty_out (vty, "Connect Time: %s %s",
           zserv_time_buf(&client->connect_time, cbuf, ZEBRA_TIME_BUF),
           VTY_NEWLINE);
  if (client->nh_reg_time)
    {
      vty_out (vty, "Nexthop Registry Time: %s %s",
               zserv_time_buf(&client->nh_reg_time, nhbuf, ZEBRA_TIME_BUF),
               VTY_NEWLINE);
      if (client->nh_last_upd_time)
        vty_out (vty, "Nexthop Last Update Time: %s %s",
                 zserv_time_buf(&client->nh_last_upd_time, mbuf, ZEBRA_TIME_BUF),
                 VTY_NEWLINE);
      else
        vty_out (vty, "No Nexthop Update sent%s", VTY_NEWLINE);
    }
  else
    vty_out (vty, "Not registered for Nexthop Updates%s", VTY_NEWLINE);

  vty_out (vty, "Last Msg Rx Time: %s %s",
           zserv_time_buf(&client->last_read_time, rbuf, ZEBRA_TIME_BUF),
           VTY_NEWLINE);
  vty_out (vty, "Last Msg Tx Time: %s %s",
           zserv_time_buf(&client->last_write_time, wbuf, ZEBRA_TIME_BUF),
           VTY_NEWLINE);
  if (client->last_read_time)
    vty_out (vty, "Last Rcvd Cmd: %s %s",
             zserv_command_string(client->last_read_cmd), VTY_NEWLINE);
  if (client->last_write_time)
    vty_out (vty, "Last Sent Cmd: %s %s",
             zserv_command_string(client->last_write_cmd), VTY_NEWLINE);
  vty_out (vty, "%s", VTY_NEWLINE);

  vty_out (vty, "Type        Add        Update     Del %s", VTY_NEWLINE);
  vty_out (vty, "================================================== %s", VTY_NEWLINE);
  vty_out (vty, "IPv4        %-12d%-12d%-12d%s", client->v4_route_add_cnt,
           client->v4_route_upd8_cnt, client->v4_route_del_cnt, VTY_NEWLINE);
  vty_out (vty, "IPv6        %-12d%-12d%-12d%s", client->v6_route_add_cnt,
           client->v6_route_upd8_cnt, client->v6_route_del_cnt, VTY_NEWLINE);
  vty_out (vty, "Redist:v4   %-12d%-12d%-12d%s", client->redist_v4_add_cnt, 0,
           client->redist_v4_del_cnt, VTY_NEWLINE);
  vty_out (vty, "Redist:v6   %-12d%-12d%-12d%s", client->redist_v6_add_cnt, 0,
           client->redist_v6_del_cnt, VTY_NEWLINE);
  vty_out (vty, "Connected   %-12d%-12d%-12d%s", client->ifadd_cnt, 0,
           client->ifdel_cnt, VTY_NEWLINE);
  vty_out (vty, "BFD peer    %-12d%-12d%-12d%s", client->bfd_peer_add_cnt,
       client->bfd_peer_upd8_cnt, client->bfd_peer_del_cnt, VTY_NEWLINE);
  vty_out (vty, "Interface Up Notifications: %d%s", client->ifup_cnt,
           VTY_NEWLINE);
  vty_out (vty, "Interface Down Notifications: %d%s", client->ifdown_cnt,
           VTY_NEWLINE);

  vty_out (vty, "%s", VTY_NEWLINE);
  return;
}

static void
zebra_show_client_brief (struct vty *vty, struct zserv *client)
{
  char cbuf[ZEBRA_TIME_BUF], rbuf[ZEBRA_TIME_BUF];
  char wbuf[ZEBRA_TIME_BUF];

  vty_out (vty, "%-8s%12s %12s%12s%8d/%-8d%8d/%-8d%s",
           zebra_route_string(client->proto),
           zserv_time_buf(&client->connect_time, cbuf, ZEBRA_TIME_BUF),
           zserv_time_buf(&client->last_read_time, rbuf, ZEBRA_TIME_BUF),
           zserv_time_buf(&client->last_write_time, wbuf, ZEBRA_TIME_BUF),
           client->v4_route_add_cnt+client->v4_route_upd8_cnt,
           client->v4_route_del_cnt,
           client->v6_route_add_cnt+client->v6_route_upd8_cnt,
           client->v6_route_del_cnt, VTY_NEWLINE);

}


/* Display default rtm_table for all clients. */
DEFUN (show_table,
       show_table_cmd,
       "show table",
       SHOW_STR
       "default routing table to use for all clients\n")
{
  vty_out (vty, "table %d%s", zebrad.rtm_table_default,
           VTY_NEWLINE);
  return CMD_SUCCESS;
}

DEFUN (config_table, 
       config_table_cmd,
       "table TABLENO",
       "Configure target kernel routing table\n"
       "TABLE integer\n")
{
  zebrad.rtm_table_default = strtol (argv[0], (char**)0, 10);
  return CMD_SUCCESS;
}

DEFUN (no_config_table,
       no_config_table_cmd,
       "no table TABLENO",
       NO_STR
       "Configure target kernel routing table\n"
       "TABLE integer\n")
{
  zebrad.rtm_table_default = 0;
  return CMD_SUCCESS;
}

DEFUN (ip_forwarding,
       ip_forwarding_cmd,
       "ip forwarding",
       IP_STR
       "Turn on IP forwarding")
{
  int ret;

  ret = ipforward ();
  if (ret == 0)
    ret = ipforward_on ();

  if (ret == 0)
    {
      vty_out (vty, "Can't turn on IP forwarding%s", VTY_NEWLINE);
      return CMD_WARNING;
    }

  return CMD_SUCCESS;
}

DEFUN (no_ip_forwarding,
       no_ip_forwarding_cmd,
       "no ip forwarding",
       NO_STR
       IP_STR
       "Turn off IP forwarding")
{
  int ret;

  ret = ipforward ();
  if (ret != 0)
    ret = ipforward_off ();

  if (ret != 0)
    {
      vty_out (vty, "Can't turn off IP forwarding%s", VTY_NEWLINE);
      return CMD_WARNING;
    }

  return CMD_SUCCESS;
}

/* This command is for debugging purpose. */
DEFUN (show_zebra_client,
       show_zebra_client_cmd,
       "show zebra client",
       SHOW_STR
       "Zebra information"
       "Client information")
{
  struct listnode *node;
  struct zserv *client;

  for (ALL_LIST_ELEMENTS_RO (zebrad.client_list, node, client))
    zebra_show_client_detail(vty, client);

  return CMD_SUCCESS;
}

/* This command is for debugging purpose. */
DEFUN (show_zebra_client_summary,
       show_zebra_client_summary_cmd,
       "show zebra client summary",
       SHOW_STR
       "Zebra information brief"
       "Client information brief")
{
  struct listnode *node;
  struct zserv *client;

  vty_out (vty, "Name    Connect Time    Last Read  Last Write  IPv4 Routes       IPv6 Routes    %s",
           VTY_NEWLINE);
  vty_out (vty,"--------------------------------------------------------------------------------%s",
           VTY_NEWLINE);

  for (ALL_LIST_ELEMENTS_RO (zebrad.client_list, node, client))
    zebra_show_client_brief(vty, client);

  vty_out (vty, "Routes column shows (added+updated)/deleted%s", VTY_NEWLINE);
  return CMD_SUCCESS;
}

/* Table configuration write function. */
static int
config_write_table (struct vty *vty)
{
  if (zebrad.rtm_table_default)
    vty_out (vty, "table %d%s", zebrad.rtm_table_default,
             VTY_NEWLINE);
  return 0;
}

/* table node for routing tables. */
static struct cmd_node table_node =
{
  TABLE_NODE,
  "",                           /* This node has no interface. */
  1
};

/* Only display ip forwarding is enabled or not. */
DEFUN (show_ip_forwarding,
       show_ip_forwarding_cmd,
       "show ip forwarding",
       SHOW_STR
       IP_STR
       "IP forwarding status\n")
{
  int ret;

  ret = ipforward ();

  if (ret == 0)
    vty_out (vty, "IP forwarding is off%s", VTY_NEWLINE);
  else
    vty_out (vty, "IP forwarding is on%s", VTY_NEWLINE);
  return CMD_SUCCESS;
}

#ifdef HAVE_IPV6
/* Only display ipv6 forwarding is enabled or not. */
DEFUN (show_ipv6_forwarding,
       show_ipv6_forwarding_cmd,
       "show ipv6 forwarding",
       SHOW_STR
       "IPv6 information\n"
       "Forwarding status\n")
{
  int ret;

  ret = ipforward_ipv6 ();

  switch (ret)
    {
    case -1:
      vty_out (vty, "ipv6 forwarding is unknown%s", VTY_NEWLINE);
      break;
    case 0:
      vty_out (vty, "ipv6 forwarding is %s%s", "off", VTY_NEWLINE);
      break;
    case 1:
      vty_out (vty, "ipv6 forwarding is %s%s", "on", VTY_NEWLINE);
      break;
    default:
      vty_out (vty, "ipv6 forwarding is %s%s", "off", VTY_NEWLINE);
      break;
    }
  return CMD_SUCCESS;
}

DEFUN (ipv6_forwarding,
       ipv6_forwarding_cmd,
       "ipv6 forwarding",
       IPV6_STR
       "Turn on IPv6 forwarding")
{
  int ret;

  ret = ipforward_ipv6 ();
  if (ret == 0)
    ret = ipforward_ipv6_on ();

  if (ret == 0)
    {
      vty_out (vty, "Can't turn on IPv6 forwarding%s", VTY_NEWLINE);
      return CMD_WARNING;
    }

  return CMD_SUCCESS;
}

DEFUN (no_ipv6_forwarding,
       no_ipv6_forwarding_cmd,
       "no ipv6 forwarding",
       NO_STR
       IPV6_STR
       "Turn off IPv6 forwarding")
{
  int ret;

  ret = ipforward_ipv6 ();
  if (ret != 0)
    ret = ipforward_ipv6_off ();

  if (ret != 0)
    {
      vty_out (vty, "Can't turn off IPv6 forwarding%s", VTY_NEWLINE);
      return CMD_WARNING;
    }

  return CMD_SUCCESS;
}

#endif /* HAVE_IPV6 */

/* IPForwarding configuration write function. */
static int
config_write_forwarding (struct vty *vty)
{
  /* FIXME: Find better place for that. */
  router_id_write (vty);

  if (!ipforward ())
    vty_out (vty, "no ip forwarding%s", VTY_NEWLINE);
#ifdef HAVE_IPV6
  if (!ipforward_ipv6 ())
    vty_out (vty, "no ipv6 forwarding%s", VTY_NEWLINE);
#endif /* HAVE_IPV6 */
  vty_out (vty, "!%s", VTY_NEWLINE);
  return 0;
}

/* table node for routing tables. */
static struct cmd_node forwarding_node =
{
  FORWARDING_NODE,
  "",                           /* This node has no interface. */
  1
};


/* Initialisation of zebra and installation of commands. */
void
zebra_init (void)
{
  /* Client list init. */
  zebrad.client_list = list_new ();

  /* Install configuration write function. */
  install_node (&table_node, config_write_table);
  install_node (&forwarding_node, config_write_forwarding);

  install_element (VIEW_NODE, &show_ip_forwarding_cmd);
  install_element (ENABLE_NODE, &show_ip_forwarding_cmd);
  install_element (CONFIG_NODE, &ip_forwarding_cmd);
  install_element (CONFIG_NODE, &no_ip_forwarding_cmd);
  install_element (ENABLE_NODE, &show_zebra_client_cmd);
  install_element (ENABLE_NODE, &show_zebra_client_summary_cmd);

#ifdef HAVE_NETLINK
  install_element (VIEW_NODE, &show_table_cmd);
  install_element (ENABLE_NODE, &show_table_cmd);
  install_element (CONFIG_NODE, &config_table_cmd);
  install_element (CONFIG_NODE, &no_config_table_cmd);
#endif /* HAVE_NETLINK */

#ifdef HAVE_IPV6
  install_element (VIEW_NODE, &show_ipv6_forwarding_cmd);
  install_element (ENABLE_NODE, &show_ipv6_forwarding_cmd);
  install_element (CONFIG_NODE, &ipv6_forwarding_cmd);
  install_element (CONFIG_NODE, &no_ipv6_forwarding_cmd);
#endif /* HAVE_IPV6 */

  /* Route-map */
  zebra_route_map_init ();
}

/* Make zebra server socket, wiping any existing one (see bug #403). */
void
zebra_zserv_socket_init (char *path)
{
#ifdef HAVE_TCP_ZEBRA
  zebra_serv ();
#else
  zebra_serv_un (path ? path : ZEBRA_SERV_PATH);
#endif /* HAVE_TCP_ZEBRA */
}