pimd/pim_zlookup.c - quagga - Gitiles

 /*
   PIM for Quagga
   Copyright (C) 2008  Everton da Silva Marques

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; see the file COPYING; if not, write to the
   Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
   MA 02110-1301 USA

   $QuaggaId: $Format:%an, %ai, %h$ $
 */

 #include <zebra.h>
 #include "zebra/rib.h"

 #include "log.h"
 #include "prefix.h"
 #include "zclient.h"
 #include "stream.h"
 #include "network.h"
 #include "thread.h"

 #include "pimd.h"
 #include "pim_pim.h"
 #include "pim_str.h"
 #include "pim_zlookup.h"

 extern int zclient_debug;

 static void zclient_lookup_sched(struct zclient *zlookup, int delay);

 /* Connect to zebra for nexthop lookup. */
 static int zclient_lookup_connect(struct thread *t)
 {
   struct zclient *zlookup;

   zlookup = THREAD_ARG(t);
   zlookup->t_connect = NULL;

   if (zlookup->sock >= 0) {
     return 0;
   }

   if (zclient_socket_connect(zlookup) < 0) {
     ++zlookup->fail;
     zlog_warn("%s: failure connecting zclient socket: failures=%d",
 	      __PRETTY_FUNCTION__, zlookup->fail);
   }
   else {
     zlookup->fail = 0; /* reset counter on connection */
   }

   zassert(!zlookup->t_connect);
   if (zlookup->sock < 0) {
     /* Since last connect failed, retry within 10 secs */
     zclient_lookup_sched(zlookup, 10);
     return -1;
   }

   return 0;
 }

 /* Schedule connection with delay. */
 static void zclient_lookup_sched(struct zclient *zlookup, int delay)
 {
   zassert(!zlookup->t_connect);

   THREAD_TIMER_ON(master, zlookup->t_connect,
 		  zclient_lookup_connect,
 		  zlookup, delay);

   zlog_notice("%s: zclient lookup connection scheduled for %d seconds",
 	      __PRETTY_FUNCTION__, delay);
 }

 /* Schedule connection for now. */
 static void zclient_lookup_sched_now(struct zclient *zlookup)
 {
   zassert(!zlookup->t_connect);

   zlookup->t_connect = thread_add_event(master, zclient_lookup_connect,
 					zlookup, 0);

   zlog_notice("%s: zclient lookup immediate connection scheduled",
 	      __PRETTY_FUNCTION__);
 }

 /* Schedule reconnection, if needed. */
 static void zclient_lookup_reconnect(struct zclient *zlookup)
 {
   if (zlookup->t_connect) {
     return;
   }

   zclient_lookup_sched_now(zlookup);
 }

 static void zclient_lookup_failed(struct zclient *zlookup)
 {
   if (zlookup->sock >= 0) {
     if (close(zlookup->sock)) {
       zlog_warn("%s: closing fd=%d: errno=%d %s", __func__, zlookup->sock,
 		errno, safe_strerror(errno));
     }
     zlookup->sock = -1;
   }

   zclient_lookup_reconnect(zlookup);
 }

 struct zclient *zclient_lookup_new()
 {
   struct zclient *zlookup;

   zlookup = zclient_new (master);
   if (!zlookup) {
     zlog_err("%s: zclient_new() failure",
 	     __PRETTY_FUNCTION__);
     return 0;
   }

   zlookup->sock = -1;
   zlookup->ibuf = stream_new(ZEBRA_MAX_PACKET_SIZ);
   zlookup->obuf = stream_new(ZEBRA_MAX_PACKET_SIZ);
   zlookup->t_connect = 0;

   zclient_lookup_sched_now(zlookup);

   zlog_notice("%s: zclient lookup socket initialized",
 	      __PRETTY_FUNCTION__);

   return zlookup;
 }

 static int zclient_read_nexthop(struct zclient *zlookup,
 				struct pim_zlookup_nexthop nexthop_tab[],
 				const int tab_size,
 				struct in_addr addr)
 {
   int num_ifindex = 0;
   struct stream *s;
   const uint16_t MIN_LEN = 10; /* getipv4=4 getc=1 getl=4 getc=1 */
   uint16_t length;
   u_char marker;
   u_char version;
   uint16_t vrf_id;
   uint16_t command;
   struct in_addr raddr;
   uint8_t distance;
   uint32_t metric;
   int nexthop_num;
   int i, err;

   if (PIM_DEBUG_ZEBRA) {
     char addr_str[100];
     pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
     zlog_debug("%s: addr=%s",
 	       __PRETTY_FUNCTION__,
 	       addr_str);
   }

   s = zlookup->ibuf;
   stream_reset(s);

   err = zclient_read_header (s, zlookup->sock, &length, &marker, &version,
                              &vrf_id, &command);
   if (err < 0) {
     zlog_err("%s %s: zclient_read_header() failed",
 	     __FILE__, __PRETTY_FUNCTION__);
     zclient_lookup_failed(zlookup);
     return -1;
   }

   if (length < MIN_LEN) {
     zlog_err("%s %s: failure reading zclient lookup socket: len=%d < MIN_LEN=%d",
 	     __FILE__, __PRETTY_FUNCTION__, length, MIN_LEN);
     zclient_lookup_failed(zlookup);
     return -2;
   }

   if (command != ZEBRA_IPV4_NEXTHOP_LOOKUP_MRIB) {
     zlog_err("%s: socket %d command mismatch: %d",
             __func__, zlookup->sock, command);
     return -5;
   }

   raddr.s_addr = stream_get_ipv4(s);

   if (raddr.s_addr != addr.s_addr) {
     char addr_str[100];
     char raddr_str[100];
     pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
     pim_inet4_dump("<raddr?>", raddr, raddr_str, sizeof(raddr_str));
     zlog_warn("%s: address mismatch: addr=%s raddr=%s",
 	       __PRETTY_FUNCTION__,
 	       addr_str, raddr_str);
     /* warning only */
   }

   distance = stream_getc(s);
   metric = stream_getl(s);
   nexthop_num = stream_getc(s);

   if (nexthop_num < 1) {
     zlog_err("%s: socket %d bad nexthop_num=%d",
             __func__, zlookup->sock, nexthop_num);
     return -6;
   }

   length -= MIN_LEN;

   for (i = 0; i < nexthop_num; ++i) {
     enum nexthop_types_t nexthop_type;

     if (length < 1) {
       zlog_err("%s: socket %d empty input expecting nexthop_type: len=%d",
 	       __func__, zlookup->sock, length);
       return -7;
     }

     nexthop_type = stream_getc(s);
     --length;

     switch (nexthop_type) {
     case ZEBRA_NEXTHOP_IFINDEX:
     case ZEBRA_NEXTHOP_IFNAME:
     case ZEBRA_NEXTHOP_IPV4_IFINDEX:
       if (num_ifindex >= tab_size) {
 	char addr_str[100];
 	pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
 	zlog_warn("%s %s: found too many nexthop ifindexes (%d > %d) for address %s",
 		 __FILE__, __PRETTY_FUNCTION__,
 		 (num_ifindex + 1), tab_size, addr_str);
 	return num_ifindex;
       }
       if (nexthop_type == ZEBRA_NEXTHOP_IPV4_IFINDEX) {
 	if (length < 4) {
 	  zlog_err("%s: socket %d short input expecting nexthop IPv4-addr: len=%d",
 		   __func__, zlookup->sock, length);
 	  return -8;
 	}
 	nexthop_tab[num_ifindex].nexthop_addr.s_addr = stream_get_ipv4(s);
 	length -= 4;
       }
       else {
 	nexthop_tab[num_ifindex].nexthop_addr.s_addr = PIM_NET_INADDR_ANY;
       }
       nexthop_tab[num_ifindex].ifindex           = stream_getl(s);
       nexthop_tab[num_ifindex].protocol_distance = distance;
       nexthop_tab[num_ifindex].route_metric      = metric;
       ++num_ifindex;
       break;
     case ZEBRA_NEXTHOP_IPV4:
       if (num_ifindex >= tab_size) {
 	char addr_str[100];
 	pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
 	zlog_warn("%s %s: found too many nexthop ifindexes (%d > %d) for address %s",
 		 __FILE__, __PRETTY_FUNCTION__,
 		 (num_ifindex + 1), tab_size, addr_str);
 	return num_ifindex;
       }
       nexthop_tab[num_ifindex].nexthop_addr.s_addr = stream_get_ipv4(s);
       length -= 4;
       nexthop_tab[num_ifindex].ifindex             = 0;
       nexthop_tab[num_ifindex].protocol_distance   = distance;
       nexthop_tab[num_ifindex].route_metric        = metric;
       if (PIM_DEBUG_ZEBRA) {
 	char addr_str[100];
 	char nexthop_str[100];
 	pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
 	pim_inet4_dump("<nexthop?>", nexthop_tab[num_ifindex].nexthop_addr, nexthop_str, sizeof(nexthop_str));
 	zlog_debug("%s %s: zebra returned recursive nexthop %s for address %s",
 		   __FILE__, __PRETTY_FUNCTION__,
 		   nexthop_str, addr_str);
       }
       ++num_ifindex;
       break;
     default:
       /* do nothing */
       {
 	char addr_str[100];
 	pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
 	zlog_warn("%s %s: found non-ifindex nexthop type=%d for address %s",
 		 __FILE__, __PRETTY_FUNCTION__,
 		  nexthop_type, addr_str);
       }
       break;
     }
   }

   return num_ifindex;
 }

 static int zclient_lookup_nexthop_once(struct zclient *zlookup,
 				       struct pim_zlookup_nexthop nexthop_tab[],
 				       const int tab_size,
 				       struct in_addr addr)
 {
   struct stream *s;
   int ret;

   if (PIM_DEBUG_ZEBRA) {
     char addr_str[100];
     pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
     zlog_debug("%s: addr=%s",
 	       __PRETTY_FUNCTION__,
 	       addr_str);
   }

   /* Check socket. */
   if (zlookup->sock < 0) {
     zlog_err("%s %s: zclient lookup socket is not connected",
 	     __FILE__, __PRETTY_FUNCTION__);
     zclient_lookup_failed(zlookup);
     return -1;
   }

   s = zlookup->obuf;
   stream_reset(s);
   zclient_create_header(s, ZEBRA_IPV4_NEXTHOP_LOOKUP_MRIB, VRF_DEFAULT);
   stream_put_in_addr(s, &addr);
   stream_putw_at(s, 0, stream_get_endp(s));

   ret = writen(zlookup->sock, s->data, stream_get_endp(s));
   if (ret < 0) {
     zlog_err("%s %s: writen() failure writing to zclient lookup socket",
 	     __FILE__, __PRETTY_FUNCTION__);
     zclient_lookup_failed(zlookup);
     return -2;
   }
   if (ret == 0) {
     zlog_err("%s %s: connection closed on zclient lookup socket",
 	     __FILE__, __PRETTY_FUNCTION__);
     zclient_lookup_failed(zlookup);
     return -3;
   }

   return zclient_read_nexthop(zlookup, nexthop_tab,
 			      tab_size, addr);
 }

 int zclient_lookup_nexthop(struct zclient *zlookup,
 			   struct pim_zlookup_nexthop nexthop_tab[],
 			   const int tab_size,
 			   struct in_addr addr,
 			   int max_lookup)
 {
   int lookup;
   uint32_t route_metric = 0xFFFFFFFF;
   uint8_t  protocol_distance = 0xFF;

   for (lookup = 0; lookup < max_lookup; ++lookup) {
     int num_ifindex;
     int first_ifindex;
     struct in_addr nexthop_addr;

     num_ifindex = zclient_lookup_nexthop_once(qpim_zclient_lookup, nexthop_tab,
 					      PIM_NEXTHOP_IFINDEX_TAB_SIZE, addr);
     if ((num_ifindex < 1) && PIM_DEBUG_ZEBRA) {
       char addr_str[100];
       pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
       zlog_warn("%s %s: lookup=%d/%d: could not find nexthop ifindex for address %s",
 		__FILE__, __PRETTY_FUNCTION__,
 		lookup, max_lookup, addr_str);
       return -1;
     }

     if (lookup < 1) {
       /* this is the non-recursive lookup - save original metric/distance */
       route_metric = nexthop_tab[0].route_metric;
       protocol_distance = nexthop_tab[0].protocol_distance;
     }

     /*
       FIXME: Non-recursive nexthop ensured only for first ifindex.
       However, recursive route lookup should really be fixed in zebra daemon.
       See also TODO T24.
      */
     first_ifindex = nexthop_tab[0].ifindex;
     nexthop_addr = nexthop_tab[0].nexthop_addr;
     if (first_ifindex > 0) {
       /* found: first ifindex is non-recursive nexthop */

       if ((lookup > 0) && PIM_DEBUG_ZEBRA) {
 	/* Report non-recursive success after first lookup */
 	char addr_str[100];
 	pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
 	zlog_debug("%s %s: lookup=%d/%d: found non-recursive ifindex=%d for address %s dist=%d met=%d",
 		   __FILE__, __PRETTY_FUNCTION__,
 		   lookup, max_lookup, first_ifindex, addr_str,
 		   nexthop_tab[0].protocol_distance,
 		   nexthop_tab[0].route_metric);

 	/* use last address as nexthop address */
 	nexthop_tab[0].nexthop_addr = addr;

 	/* report original route metric/distance */
 	nexthop_tab[0].route_metric = route_metric;
 	nexthop_tab[0].protocol_distance = protocol_distance;
       }

       return num_ifindex;
     }

     if (PIM_DEBUG_ZEBRA) {
       char addr_str[100];
       char nexthop_str[100];
       pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
       pim_inet4_dump("<nexthop?>", nexthop_addr, nexthop_str, sizeof(nexthop_str));
       zlog_debug("%s %s: lookup=%d/%d: zebra returned recursive nexthop %s for address %s dist=%d met=%d",
 		__FILE__, __PRETTY_FUNCTION__,
 		lookup, max_lookup, nexthop_str, addr_str,
 		nexthop_tab[0].protocol_distance,
 		nexthop_tab[0].route_metric);
     }

     addr = nexthop_addr; /* use nexthop addr for recursive lookup */

   } /* for (max_lookup) */

   if (PIM_DEBUG_ZEBRA) {
     char addr_str[100];
     pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
     zlog_warn("%s %s: lookup=%d/%d: failure searching recursive nexthop ifindex for address %s",
 	      __FILE__, __PRETTY_FUNCTION__,
 	      lookup, max_lookup, addr_str);
   }

   return -2;
 }
	/*
	PIM for Quagga
	Copyright (C) 2008 Everton da Silva Marques

	This program is free software; you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation; either version 2 of the License, or
	(at your option) any later version.

	This program is distributed in the hope that it will be useful, but
	WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program; see the file COPYING; if not, write to the
	Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
	MA 02110-1301 USA

	$QuaggaId: $Format:%an, %ai, %h$ $
	*/

	#include <zebra.h>
	#include "zebra/rib.h"

	#include "log.h"
	#include "prefix.h"
	#include "zclient.h"
	#include "stream.h"
	#include "network.h"
	#include "thread.h"

	#include "pimd.h"
	#include "pim_pim.h"
	#include "pim_str.h"
	#include "pim_zlookup.h"

	extern int zclient_debug;

	static void zclient_lookup_sched(struct zclient *zlookup, int delay);

	/* Connect to zebra for nexthop lookup. */
	static int zclient_lookup_connect(struct thread *t)
	{
	struct zclient *zlookup;

	zlookup = THREAD_ARG(t);
	zlookup->t_connect = NULL;

	if (zlookup->sock >= 0) {
	return 0;
	}

	if (zclient_socket_connect(zlookup) < 0) {
	++zlookup->fail;
	zlog_warn("%s: failure connecting zclient socket: failures=%d",
	__PRETTY_FUNCTION__, zlookup->fail);
	}
	else {
	zlookup->fail = 0; /* reset counter on connection */
	}

	zassert(!zlookup->t_connect);
	if (zlookup->sock < 0) {
	/* Since last connect failed, retry within 10 secs */
	zclient_lookup_sched(zlookup, 10);
	return -1;
	}

	return 0;
	}

	/* Schedule connection with delay. */
	static void zclient_lookup_sched(struct zclient *zlookup, int delay)
	{
	zassert(!zlookup->t_connect);

	THREAD_TIMER_ON(master, zlookup->t_connect,
	zclient_lookup_connect,
	zlookup, delay);

	zlog_notice("%s: zclient lookup connection scheduled for %d seconds",
	__PRETTY_FUNCTION__, delay);
	}

	/* Schedule connection for now. */
	static void zclient_lookup_sched_now(struct zclient *zlookup)
	{
	zassert(!zlookup->t_connect);

	zlookup->t_connect = thread_add_event(master, zclient_lookup_connect,
	zlookup, 0);

	zlog_notice("%s: zclient lookup immediate connection scheduled",
	__PRETTY_FUNCTION__);
	}

	/* Schedule reconnection, if needed. */
	static void zclient_lookup_reconnect(struct zclient *zlookup)
	{
	if (zlookup->t_connect) {
	return;
	}

	zclient_lookup_sched_now(zlookup);
	}

	static void zclient_lookup_failed(struct zclient *zlookup)
	{
	if (zlookup->sock >= 0) {
	if (close(zlookup->sock)) {
	zlog_warn("%s: closing fd=%d: errno=%d %s", __func__, zlookup->sock,
	errno, safe_strerror(errno));
	}
	zlookup->sock = -1;
	}

	zclient_lookup_reconnect(zlookup);
	}

	struct zclient *zclient_lookup_new()
	{
	struct zclient *zlookup;

	zlookup = zclient_new (master);
	if (!zlookup) {
	zlog_err("%s: zclient_new() failure",
	__PRETTY_FUNCTION__);
	return 0;
	}

	zlookup->sock = -1;
	zlookup->ibuf = stream_new(ZEBRA_MAX_PACKET_SIZ);
	zlookup->obuf = stream_new(ZEBRA_MAX_PACKET_SIZ);
	zlookup->t_connect = 0;

	zclient_lookup_sched_now(zlookup);

	zlog_notice("%s: zclient lookup socket initialized",
	__PRETTY_FUNCTION__);

	return zlookup;
	}

	static int zclient_read_nexthop(struct zclient *zlookup,
	struct pim_zlookup_nexthop nexthop_tab[],
	const int tab_size,
	struct in_addr addr)
	{
	int num_ifindex = 0;
	struct stream *s;
	const uint16_t MIN_LEN = 10; /* getipv4=4 getc=1 getl=4 getc=1 */
	uint16_t length;
	u_char marker;
	u_char version;
	uint16_t vrf_id;
	uint16_t command;
	struct in_addr raddr;
	uint8_t distance;
	uint32_t metric;
	int nexthop_num;
	int i, err;

	if (PIM_DEBUG_ZEBRA) {
	char addr_str[100];
	pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
	zlog_debug("%s: addr=%s",
	__PRETTY_FUNCTION__,
	addr_str);
	}

	s = zlookup->ibuf;
	stream_reset(s);

	err = zclient_read_header (s, zlookup->sock, &length, &marker, &version,
	&vrf_id, &command);
	if (err < 0) {
	zlog_err("%s %s: zclient_read_header() failed",
	__FILE__, __PRETTY_FUNCTION__);
	zclient_lookup_failed(zlookup);
	return -1;
	}

	if (length < MIN_LEN) {
	zlog_err("%s %s: failure reading zclient lookup socket: len=%d < MIN_LEN=%d",
	__FILE__, __PRETTY_FUNCTION__, length, MIN_LEN);
	zclient_lookup_failed(zlookup);
	return -2;
	}

	if (command != ZEBRA_IPV4_NEXTHOP_LOOKUP_MRIB) {
	zlog_err("%s: socket %d command mismatch: %d",
	__func__, zlookup->sock, command);
	return -5;
	}

	raddr.s_addr = stream_get_ipv4(s);

	if (raddr.s_addr != addr.s_addr) {
	char addr_str[100];
	char raddr_str[100];
	pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
	pim_inet4_dump("<raddr?>", raddr, raddr_str, sizeof(raddr_str));
	zlog_warn("%s: address mismatch: addr=%s raddr=%s",
	__PRETTY_FUNCTION__,
	addr_str, raddr_str);
	/* warning only */
	}

	distance = stream_getc(s);
	metric = stream_getl(s);
	nexthop_num = stream_getc(s);

	if (nexthop_num < 1) {
	zlog_err("%s: socket %d bad nexthop_num=%d",
	__func__, zlookup->sock, nexthop_num);
	return -6;
	}

	length -= MIN_LEN;

	for (i = 0; i < nexthop_num; ++i) {
	enum nexthop_types_t nexthop_type;

	if (length < 1) {
	zlog_err("%s: socket %d empty input expecting nexthop_type: len=%d",
	__func__, zlookup->sock, length);
	return -7;
	}

	nexthop_type = stream_getc(s);
	--length;

	switch (nexthop_type) {
	case ZEBRA_NEXTHOP_IFINDEX:
	case ZEBRA_NEXTHOP_IFNAME:
	case ZEBRA_NEXTHOP_IPV4_IFINDEX:
	if (num_ifindex >= tab_size) {
	char addr_str[100];
	pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
	zlog_warn("%s %s: found too many nexthop ifindexes (%d > %d) for address %s",
	__FILE__, __PRETTY_FUNCTION__,
	(num_ifindex + 1), tab_size, addr_str);
	return num_ifindex;
	}
	if (nexthop_type == ZEBRA_NEXTHOP_IPV4_IFINDEX) {
	if (length < 4) {
	zlog_err("%s: socket %d short input expecting nexthop IPv4-addr: len=%d",
	__func__, zlookup->sock, length);
	return -8;
	}
	nexthop_tab[num_ifindex].nexthop_addr.s_addr = stream_get_ipv4(s);
	length -= 4;
	}
	else {
	nexthop_tab[num_ifindex].nexthop_addr.s_addr = PIM_NET_INADDR_ANY;
	}
	nexthop_tab[num_ifindex].ifindex = stream_getl(s);
	nexthop_tab[num_ifindex].protocol_distance = distance;
	nexthop_tab[num_ifindex].route_metric = metric;
	++num_ifindex;
	break;
	case ZEBRA_NEXTHOP_IPV4:
	if (num_ifindex >= tab_size) {
	char addr_str[100];
	pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
	zlog_warn("%s %s: found too many nexthop ifindexes (%d > %d) for address %s",
	__FILE__, __PRETTY_FUNCTION__,
	(num_ifindex + 1), tab_size, addr_str);
	return num_ifindex;
	}
	nexthop_tab[num_ifindex].nexthop_addr.s_addr = stream_get_ipv4(s);
	length -= 4;
	nexthop_tab[num_ifindex].ifindex = 0;
	nexthop_tab[num_ifindex].protocol_distance = distance;
	nexthop_tab[num_ifindex].route_metric = metric;
	if (PIM_DEBUG_ZEBRA) {
	char addr_str[100];
	char nexthop_str[100];
	pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
	pim_inet4_dump("<nexthop?>", nexthop_tab[num_ifindex].nexthop_addr, nexthop_str, sizeof(nexthop_str));
	zlog_debug("%s %s: zebra returned recursive nexthop %s for address %s",
	__FILE__, __PRETTY_FUNCTION__,
	nexthop_str, addr_str);
	}
	++num_ifindex;
	break;
	default:
	/* do nothing */
	{
	char addr_str[100];
	pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
	zlog_warn("%s %s: found non-ifindex nexthop type=%d for address %s",
	__FILE__, __PRETTY_FUNCTION__,
	nexthop_type, addr_str);
	}
	break;
	}
	}

	return num_ifindex;
	}

	static int zclient_lookup_nexthop_once(struct zclient *zlookup,
	struct pim_zlookup_nexthop nexthop_tab[],
	const int tab_size,
	struct in_addr addr)
	{
	struct stream *s;
	int ret;

	if (PIM_DEBUG_ZEBRA) {
	char addr_str[100];
	pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
	zlog_debug("%s: addr=%s",
	__PRETTY_FUNCTION__,
	addr_str);
	}

	/* Check socket. */
	if (zlookup->sock < 0) {
	zlog_err("%s %s: zclient lookup socket is not connected",
	__FILE__, __PRETTY_FUNCTION__);
	zclient_lookup_failed(zlookup);
	return -1;
	}

	s = zlookup->obuf;
	stream_reset(s);
	zclient_create_header(s, ZEBRA_IPV4_NEXTHOP_LOOKUP_MRIB, VRF_DEFAULT);
	stream_put_in_addr(s, &addr);
	stream_putw_at(s, 0, stream_get_endp(s));

	ret = writen(zlookup->sock, s->data, stream_get_endp(s));
	if (ret < 0) {
	zlog_err("%s %s: writen() failure writing to zclient lookup socket",
	__FILE__, __PRETTY_FUNCTION__);
	zclient_lookup_failed(zlookup);
	return -2;
	}
	if (ret == 0) {
	zlog_err("%s %s: connection closed on zclient lookup socket",
	__FILE__, __PRETTY_FUNCTION__);
	zclient_lookup_failed(zlookup);
	return -3;
	}

	return zclient_read_nexthop(zlookup, nexthop_tab,
	tab_size, addr);
	}

	int zclient_lookup_nexthop(struct zclient *zlookup,
	struct pim_zlookup_nexthop nexthop_tab[],
	const int tab_size,
	struct in_addr addr,
	int max_lookup)
	{
	int lookup;
	uint32_t route_metric = 0xFFFFFFFF;
	uint8_t protocol_distance = 0xFF;

	for (lookup = 0; lookup < max_lookup; ++lookup) {
	int num_ifindex;
	int first_ifindex;
	struct in_addr nexthop_addr;

	num_ifindex = zclient_lookup_nexthop_once(qpim_zclient_lookup, nexthop_tab,
	PIM_NEXTHOP_IFINDEX_TAB_SIZE, addr);
	if ((num_ifindex < 1) && PIM_DEBUG_ZEBRA) {
	char addr_str[100];
	pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
	zlog_warn("%s %s: lookup=%d/%d: could not find nexthop ifindex for address %s",
	__FILE__, __PRETTY_FUNCTION__,
	lookup, max_lookup, addr_str);
	return -1;
	}

	if (lookup < 1) {
	/* this is the non-recursive lookup - save original metric/distance */
	route_metric = nexthop_tab[0].route_metric;
	protocol_distance = nexthop_tab[0].protocol_distance;
	}

	/*
	FIXME: Non-recursive nexthop ensured only for first ifindex.
	However, recursive route lookup should really be fixed in zebra daemon.
	See also TODO T24.
	*/
	first_ifindex = nexthop_tab[0].ifindex;
	nexthop_addr = nexthop_tab[0].nexthop_addr;
	if (first_ifindex > 0) {
	/* found: first ifindex is non-recursive nexthop */

	if ((lookup > 0) && PIM_DEBUG_ZEBRA) {
	/* Report non-recursive success after first lookup */
	char addr_str[100];
	pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
	zlog_debug("%s %s: lookup=%d/%d: found non-recursive ifindex=%d for address %s dist=%d met=%d",
	__FILE__, __PRETTY_FUNCTION__,
	lookup, max_lookup, first_ifindex, addr_str,
	nexthop_tab[0].protocol_distance,
	nexthop_tab[0].route_metric);

	/* use last address as nexthop address */
	nexthop_tab[0].nexthop_addr = addr;

	/* report original route metric/distance */
	nexthop_tab[0].route_metric = route_metric;
	nexthop_tab[0].protocol_distance = protocol_distance;
	}

	return num_ifindex;
	}

	if (PIM_DEBUG_ZEBRA) {
	char addr_str[100];
	char nexthop_str[100];
	pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
	pim_inet4_dump("<nexthop?>", nexthop_addr, nexthop_str, sizeof(nexthop_str));
	zlog_debug("%s %s: lookup=%d/%d: zebra returned recursive nexthop %s for address %s dist=%d met=%d",
	__FILE__, __PRETTY_FUNCTION__,
	lookup, max_lookup, nexthop_str, addr_str,
	nexthop_tab[0].protocol_distance,
	nexthop_tab[0].route_metric);
	}

	addr = nexthop_addr; /* use nexthop addr for recursive lookup */

	} /* for (max_lookup) */

	if (PIM_DEBUG_ZEBRA) {
	char addr_str[100];
	pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
	zlog_warn("%s %s: lookup=%d/%d: failure searching recursive nexthop ifindex for address %s",
	__FILE__, __PRETTY_FUNCTION__,
	lookup, max_lookup, addr_str);
	}

	return -2;
	}