src/cache-ct.c - manifest_repos/conntrack-tools - Git at Google

 /*
  * (C) 2006-2011 by Pablo Neira Ayuso <pablo@netfilter.org>
  * (C) 2011 by Vyatta Inc. <http://www.vyatta.com>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */

 #include "cache.h"
 #include "hash.h"
 #include "log.h"
 #include "conntrackd.h"
 #include "netlink.h"
 #include "event.h"
 #include "jhash.h"
 #include "network.h"

 #include <errno.h>
 #include <string.h>
 #include <time.h>
 #include <libnetfilter_conntrack/libnetfilter_conntrack.h>

 static uint32_t
 cache_hash4_ct(const struct nf_conntrack *ct, const struct hashtable *table)
 {
 	uint32_t a[4] = {
 		[0]	= nfct_get_attr_u32(ct, ATTR_IPV4_SRC),
 		[1]	= nfct_get_attr_u32(ct, ATTR_IPV4_DST),
 		[2]	= nfct_get_attr_u8(ct, ATTR_L3PROTO) << 16 |
 			  nfct_get_attr_u8(ct, ATTR_L4PROTO),
 		[3]	= nfct_get_attr_u16(ct, ATTR_PORT_SRC) << 16 |
 			  nfct_get_attr_u16(ct, ATTR_PORT_DST),
 	};

 	/*
 	 * Instead of returning hash % table->hashsize (implying a divide)
 	 * we return the high 32 bits of the (hash * table->hashsize) that will
 	 * give results between [0 and hashsize-1] and same hash distribution,
 	 * but using a multiply, less expensive than a divide. See:
 	 * http://www.mail-archive.com/netdev@vger.kernel.org/msg56623.html
 	 */
 	return ((uint64_t)jhash2(a, 4, 0) * table->hashsize) >> 32;
 }

 static uint32_t
 cache_hash6_ct(const struct nf_conntrack *ct, const struct hashtable *table)
 {
 	uint32_t a[10];

 	memcpy(&a[0], nfct_get_attr(ct, ATTR_IPV6_SRC), sizeof(uint32_t)*4);
 	memcpy(&a[4], nfct_get_attr(ct, ATTR_IPV6_DST), sizeof(uint32_t)*4);
 	a[8] = nfct_get_attr_u8(ct, ATTR_ORIG_L3PROTO) << 16 |
 	       nfct_get_attr_u8(ct, ATTR_ORIG_L4PROTO);
 	a[9] = nfct_get_attr_u16(ct, ATTR_ORIG_PORT_SRC) << 16 |
 	       nfct_get_attr_u16(ct, ATTR_ORIG_PORT_DST);

 	return ((uint64_t)jhash2(a, 10, 0) * table->hashsize) >> 32;
 }

 static uint32_t
 cache_ct_hash(const void *data, const struct hashtable *table)
 {
 	int ret = 0;
 	const struct nf_conntrack *ct = data;

 	switch(nfct_get_attr_u8(ct, ATTR_L3PROTO)) {
 		case AF_INET:
 			ret = cache_hash4_ct(ct, table);
 			break;
 		case AF_INET6:
 			ret = cache_hash6_ct(ct, table);
 			break;
 		default:
 			dlog(LOG_ERR, "unknown layer 3 proto in hash");
 			break;
 	}
 	return ret;
 }

 /* master conntrack of expectations have no ID */
 static inline int
 cache_ct_cmp_id(const struct nf_conntrack *ct1, const struct nf_conntrack *ct2)
 {
 	return nfct_attr_is_set(ct2, ATTR_ID) ?
 	       nfct_get_attr_u32(ct1, ATTR_ID) == nfct_get_attr_u32(ct2, ATTR_ID) : 1;
 }

 static int cache_ct_cmp(const void *data1, const void *data2)
 {
 	const struct cache_object *obj = data1;
 	const struct nf_conntrack *ct = data2;

 	return nfct_cmp(obj->ptr, ct, NFCT_CMP_ORIG) &&
 	       cache_ct_cmp_id(obj->ptr, ct);
 }

 static void *cache_ct_alloc(void)
 {
 	return nfct_new();
 }

 static void cache_ct_free(void *ptr)
 {
 	nfct_destroy(ptr);
 }

 static void cache_ct_copy(void *dst, void *src, unsigned int flags)
 {
 	nfct_copy(dst, src, flags);
 }

 static int cache_ct_dump_step(void *data1, void *n)
 {
 	char buf[1024];
 	int size;
 	struct __dump_container *container = data1;
 	struct cache_object *obj = n;
 	char *data = obj->data;
 	unsigned i;

 	/*
 	 * XXX: Do not dump the entries that are scheduled to expire.
 	 * 	These entries talk about already destroyed connections
 	 * 	that we keep for some time just in case that we have to
 	 * 	resent some lost messages. We do not show them to the
 	 * 	user as he may think that the firewall replicas are not
 	 * 	in sync. The branch below is a hack as it is quite
 	 * 	specific and it breaks conntrackd modularity. Probably
 	 * 	there's a nicer way to do this but until I come up with it...
 	 */
 	if (CONFIG(flags) & CTD_SYNC_FTFW && obj->status == C_OBJ_DEAD)
 		return 0;

 	/* do not show cached timeout, this may confuse users */
 	if (nfct_attr_is_set(obj->ptr, ATTR_TIMEOUT))
 		nfct_attr_unset(obj->ptr, ATTR_TIMEOUT);

 	memset(buf, 0, sizeof(buf));
 	size = nfct_snprintf(buf,
 			     sizeof(buf),
 			     obj->ptr,
 			     NFCT_T_UNKNOWN,
 			     container->type,
 			     0);

 	for (i = 0; i < obj->cache->num_features; i++) {
 		if (obj->cache->features[i]->dump) {
 			size += obj->cache->features[i]->dump(obj,
 							      data,
 							      buf+size,
 							      container->type);
 			data += obj->cache->features[i]->size;
 		}
 	}
 	if (container->type != NFCT_O_XML) {
 		long tm = time(NULL);
 		size += sprintf(buf+size, " [active since %lds]",
 				tm - obj->lifetime);
 	}
 	size += sprintf(buf+size, "\n");
 	if (send(container->fd, buf, size, 0) == -1) {
 		if (errno != EPIPE)
 			return -1;
 	}

 	return 0;
 }

 static void
 cache_ct_commit_step(struct __commit_container *tmp, struct cache_object *obj)
 {
 	int ret, retry = 1, timeout;
 	struct nf_conntrack *ct = obj->ptr;

 	if (CONFIG(commit_timeout)) {
 		timeout = CONFIG(commit_timeout);
 	} else {
 		timeout = time(NULL) - obj->lastupdate;
 		if (timeout < 0) {
 			/* XXX: Arbitrarily set the timer to one minute, how
 			 * can this happen? For example, an adjustment due to
 			 * daylight-saving. Probably other situations can
 			 * trigger this. */
 			timeout = 60;
 		}
 		/* calculate an estimation of the current timeout */
 		timeout = nfct_get_attr_u32(ct, ATTR_TIMEOUT) - timeout;
 		if (timeout < 0) {
 			timeout = 60;
 		}
 	}

 retry:
 	if (nl_create_conntrack(tmp->h, ct, timeout) == -1) {
 		if (errno == EEXIST && retry == 1) {
 			ret = nl_destroy_conntrack(tmp->h, ct);
 			if (ret == 0 || (ret == -1 && errno == ENOENT)) {
 				if (retry) {
 					retry = 0;
 					goto retry;
 				}
 			}
 			dlog(LOG_ERR, "commit-destroy: %s", strerror(errno));
 			dlog_ct(STATE(log), ct, NFCT_O_PLAIN);
 			tmp->c->stats.commit_fail++;
 		} else {
 			dlog(LOG_ERR, "commit-create: %s", strerror(errno));
 			dlog_ct(STATE(log), ct, NFCT_O_PLAIN);
 			tmp->c->stats.commit_fail++;
 		}
 	} else {
 		tmp->c->stats.commit_ok++;
 	}
 }

 static int cache_ct_commit_related(void *data, void *n)
 {
 	struct cache_object *obj = n;

 	if (ct_is_related(obj->ptr))
 		cache_ct_commit_step(data, obj);

 	/* keep iterating even if we have found errors */
 	return 0;
 }

 static int cache_ct_commit_master(void *data, void *n)
 {
 	struct cache_object *obj = n;

 	if (ct_is_related(obj->ptr))
 		return 0;

 	cache_ct_commit_step(data, obj);
 	return 0;
 }

 static int cache_ct_commit(struct cache *c, struct nfct_handle *h, int clientfd)
 {
 	unsigned int commit_ok, commit_fail;
 	struct __commit_container tmp = {
 		.h = h,
 		.c = c,
 	};
 	struct timeval commit_stop, res;

 	/* we already have one commit in progress, skip this. The clientfd
 	 * descriptor has to be closed by the caller. */
 	if (clientfd && STATE_SYNC(commit).clientfd != -1)
 		return -1;

 	switch(STATE_SYNC(commit).state) {
 	case COMMIT_STATE_INACTIVE:
 		gettimeofday(&STATE_SYNC(commit).stats.start, NULL);
 		STATE_SYNC(commit).stats.ok = c->stats.commit_ok;
 		STATE_SYNC(commit).stats.fail = c->stats.commit_fail;
 		STATE_SYNC(commit).clientfd = clientfd;
 	case COMMIT_STATE_MASTER:
 		STATE_SYNC(commit).current =
 			hashtable_iterate_limit(c->h, &tmp,
 						STATE_SYNC(commit).current,
 						CONFIG(general).commit_steps,
 						cache_ct_commit_master);
 		if (STATE_SYNC(commit).current < CONFIG(hashsize)) {
 			STATE_SYNC(commit).state = COMMIT_STATE_MASTER;
 			/* give it another step as soon as possible */
 			write_evfd(STATE_SYNC(commit).evfd);
 			return 1;
 		}
 		STATE_SYNC(commit).current = 0;
 		STATE_SYNC(commit).state = COMMIT_STATE_RELATED;
 	case COMMIT_STATE_RELATED:
 		STATE_SYNC(commit).current =
 			hashtable_iterate_limit(c->h, &tmp,
 						STATE_SYNC(commit).current,
 						CONFIG(general).commit_steps,
 						cache_ct_commit_related);
 		if (STATE_SYNC(commit).current < CONFIG(hashsize)) {
 			STATE_SYNC(commit).state = COMMIT_STATE_RELATED;
 			/* give it another step as soon as possible */
 			write_evfd(STATE_SYNC(commit).evfd);
 			return 1;
 		}
 		/* calculate the time that commit has taken */
 		gettimeofday(&commit_stop, NULL);
 		timersub(&commit_stop, &STATE_SYNC(commit).stats.start, &res);

 		/* calculate new entries committed */
 		commit_ok = c->stats.commit_ok - STATE_SYNC(commit).stats.ok;
 		commit_fail =
 			c->stats.commit_fail - STATE_SYNC(commit).stats.fail;

 		/* log results */
 		dlog(LOG_NOTICE, "Committed %u new entries", commit_ok);

 		if (commit_fail)
 			dlog(LOG_NOTICE, "%u entries can't be "
 					 "committed", commit_fail);

 		dlog(LOG_NOTICE, "commit has taken %lu.%06lu seconds",
 				res.tv_sec, res.tv_usec);

 		/* prepare the state machine for new commits */
 		STATE_SYNC(commit).current = 0;
 		STATE_SYNC(commit).state = COMMIT_STATE_INACTIVE;

 		return 0;
 	}
 	return 1;
 }

 static struct nethdr *
 cache_ct_build_msg(const struct cache_object *obj, int type)
 {
 	return BUILD_NETMSG_FROM_CT(obj->ptr, type);
 }

 /* template to cache conntracks coming from the kernel. */
 struct cache_ops cache_sync_internal_ct_ops = {
 	.hash		= cache_ct_hash,
 	.cmp		= cache_ct_cmp,
 	.alloc		= cache_ct_alloc,
 	.free		= cache_ct_free,
 	.copy		= cache_ct_copy,
 	.dump_step	= cache_ct_dump_step,
 	.commit		= NULL,
 	.build_msg	= cache_ct_build_msg,
 };

 /* template to cache conntracks coming from the network. */
 struct cache_ops cache_sync_external_ct_ops = {
 	.hash		= cache_ct_hash,
 	.cmp		= cache_ct_cmp,
 	.alloc		= cache_ct_alloc,
 	.free		= cache_ct_free,
 	.copy		= cache_ct_copy,
 	.dump_step	= cache_ct_dump_step,
 	.commit		= cache_ct_commit,
 	.build_msg	= NULL,
 };

 /* template to cache conntracks for the statistics mode. */
 struct cache_ops cache_stats_ct_ops = {
 	.hash		= cache_ct_hash,
 	.cmp		= cache_ct_cmp,
 	.alloc		= cache_ct_alloc,
 	.free		= cache_ct_free,
 	.copy		= cache_ct_copy,
 	.dump_step	= cache_ct_dump_step,
 	.commit		= NULL,
 	.build_msg	= NULL,
 };
	/*
	* (C) 2006-2011 by Pablo Neira Ayuso <pablo@netfilter.org>
	* (C) 2011 by Vyatta Inc. <http://www.vyatta.com>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, write to the Free Software
	* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	*/

	#include "cache.h"
	#include "hash.h"
	#include "log.h"
	#include "conntrackd.h"
	#include "netlink.h"
	#include "event.h"
	#include "jhash.h"
	#include "network.h"

	#include <errno.h>
	#include <string.h>
	#include <time.h>
	#include <libnetfilter_conntrack/libnetfilter_conntrack.h>

	static uint32_t
	cache_hash4_ct(const struct nf_conntrack ct, const struct hashtable table)
	{
	uint32_t a[4] = {
	[0] = nfct_get_attr_u32(ct, ATTR_IPV4_SRC),
	[1] = nfct_get_attr_u32(ct, ATTR_IPV4_DST),
	[2] = nfct_get_attr_u8(ct, ATTR_L3PROTO) << 16 \|
	nfct_get_attr_u8(ct, ATTR_L4PROTO),
	[3] = nfct_get_attr_u16(ct, ATTR_PORT_SRC) << 16 \|
	nfct_get_attr_u16(ct, ATTR_PORT_DST),
	};

	/*
	* Instead of returning hash % table->hashsize (implying a divide)
	* we return the high 32 bits of the (hash * table->hashsize) that will
	* give results between [0 and hashsize-1] and same hash distribution,
	* but using a multiply, less expensive than a divide. See:
	* http://www.mail-archive.com/netdev@vger.kernel.org/msg56623.html
	*/
	return ((uint64_t)jhash2(a, 4, 0) * table->hashsize) >> 32;
	}

	static uint32_t
	cache_hash6_ct(const struct nf_conntrack ct, const struct hashtable table)
	{
	uint32_t a[10];

	memcpy(&a[0], nfct_get_attr(ct, ATTR_IPV6_SRC), sizeof(uint32_t)*4);
	memcpy(&a[4], nfct_get_attr(ct, ATTR_IPV6_DST), sizeof(uint32_t)*4);
	a[8] = nfct_get_attr_u8(ct, ATTR_ORIG_L3PROTO) << 16 \|
	nfct_get_attr_u8(ct, ATTR_ORIG_L4PROTO);
	a[9] = nfct_get_attr_u16(ct, ATTR_ORIG_PORT_SRC) << 16 \|
	nfct_get_attr_u16(ct, ATTR_ORIG_PORT_DST);

	return ((uint64_t)jhash2(a, 10, 0) * table->hashsize) >> 32;
	}

	static uint32_t
	cache_ct_hash(const void data, const struct hashtable table)
	{
	int ret = 0;
	const struct nf_conntrack *ct = data;

	switch(nfct_get_attr_u8(ct, ATTR_L3PROTO)) {
	case AF_INET:
	ret = cache_hash4_ct(ct, table);
	break;
	case AF_INET6:
	ret = cache_hash6_ct(ct, table);
	break;
	default:
	dlog(LOG_ERR, "unknown layer 3 proto in hash");
	break;
	}
	return ret;
	}

	/* master conntrack of expectations have no ID */
	static inline int
	cache_ct_cmp_id(const struct nf_conntrack ct1, const struct nf_conntrack ct2)
	{
	return nfct_attr_is_set(ct2, ATTR_ID) ?
	nfct_get_attr_u32(ct1, ATTR_ID) == nfct_get_attr_u32(ct2, ATTR_ID) : 1;
	}

	static int cache_ct_cmp(const void data1, const void data2)
	{
	const struct cache_object *obj = data1;
	const struct nf_conntrack *ct = data2;

	return nfct_cmp(obj->ptr, ct, NFCT_CMP_ORIG) &&
	cache_ct_cmp_id(obj->ptr, ct);
	}

	static void *cache_ct_alloc(void)
	{
	return nfct_new();
	}

	static void cache_ct_free(void *ptr)
	{
	nfct_destroy(ptr);
	}

	static void cache_ct_copy(void dst, void src, unsigned int flags)
	{
	nfct_copy(dst, src, flags);
	}

	static int cache_ct_dump_step(void data1, void n)
	{
	char buf[1024];
	int size;
	struct __dump_container *container = data1;
	struct cache_object *obj = n;
	char *data = obj->data;
	unsigned i;

	/*
	* XXX: Do not dump the entries that are scheduled to expire.
	* These entries talk about already destroyed connections
	* that we keep for some time just in case that we have to
	* resent some lost messages. We do not show them to the
	* user as he may think that the firewall replicas are not
	* in sync. The branch below is a hack as it is quite
	* specific and it breaks conntrackd modularity. Probably
	* there's a nicer way to do this but until I come up with it...
	*/
	if (CONFIG(flags) & CTD_SYNC_FTFW && obj->status == C_OBJ_DEAD)
	return 0;

	/* do not show cached timeout, this may confuse users */
	if (nfct_attr_is_set(obj->ptr, ATTR_TIMEOUT))
	nfct_attr_unset(obj->ptr, ATTR_TIMEOUT);

	memset(buf, 0, sizeof(buf));
	size = nfct_snprintf(buf,
	sizeof(buf),
	obj->ptr,
	NFCT_T_UNKNOWN,
	container->type,
	0);

	for (i = 0; i < obj->cache->num_features; i++) {
	if (obj->cache->features[i]->dump) {
	size += obj->cache->features[i]->dump(obj,
	data,
	buf+size,
	container->type);
	data += obj->cache->features[i]->size;
	}
	}
	if (container->type != NFCT_O_XML) {
	long tm = time(NULL);
	size += sprintf(buf+size, " [active since %lds]",
	tm - obj->lifetime);
	}
	size += sprintf(buf+size, "\n");
	if (send(container->fd, buf, size, 0) == -1) {
	if (errno != EPIPE)
	return -1;
	}

	return 0;
	}

	static void
	cache_ct_commit_step(struct __commit_container tmp, struct cache_object obj)
	{
	int ret, retry = 1, timeout;
	struct nf_conntrack *ct = obj->ptr;

	if (CONFIG(commit_timeout)) {
	timeout = CONFIG(commit_timeout);
	} else {
	timeout = time(NULL) - obj->lastupdate;
	if (timeout < 0) {
	/* XXX: Arbitrarily set the timer to one minute, how
	* can this happen? For example, an adjustment due to
	* daylight-saving. Probably other situations can
	* trigger this. */
	timeout = 60;
	}
	/* calculate an estimation of the current timeout */
	timeout = nfct_get_attr_u32(ct, ATTR_TIMEOUT) - timeout;
	if (timeout < 0) {
	timeout = 60;
	}
	}

	retry:
	if (nl_create_conntrack(tmp->h, ct, timeout) == -1) {
	if (errno == EEXIST && retry == 1) {
	ret = nl_destroy_conntrack(tmp->h, ct);
	if (ret == 0 \|\| (ret == -1 && errno == ENOENT)) {
	if (retry) {
	retry = 0;
	goto retry;
	}
	}
	dlog(LOG_ERR, "commit-destroy: %s", strerror(errno));
	dlog_ct(STATE(log), ct, NFCT_O_PLAIN);
	tmp->c->stats.commit_fail++;
	} else {
	dlog(LOG_ERR, "commit-create: %s", strerror(errno));
	dlog_ct(STATE(log), ct, NFCT_O_PLAIN);
	tmp->c->stats.commit_fail++;
	}
	} else {
	tmp->c->stats.commit_ok++;
	}
	}

	static int cache_ct_commit_related(void data, void n)
	{
	struct cache_object *obj = n;

	if (ct_is_related(obj->ptr))
	cache_ct_commit_step(data, obj);

	/* keep iterating even if we have found errors */
	return 0;
	}

	static int cache_ct_commit_master(void data, void n)
	{
	struct cache_object *obj = n;

	if (ct_is_related(obj->ptr))
	return 0;

	cache_ct_commit_step(data, obj);
	return 0;
	}

	static int cache_ct_commit(struct cache c, struct nfct_handle h, int clientfd)
	{
	unsigned int commit_ok, commit_fail;
	struct __commit_container tmp = {
	.h = h,
	.c = c,
	};
	struct timeval commit_stop, res;

	/* we already have one commit in progress, skip this. The clientfd
	* descriptor has to be closed by the caller. */
	if (clientfd && STATE_SYNC(commit).clientfd != -1)
	return -1;

	switch(STATE_SYNC(commit).state) {
	case COMMIT_STATE_INACTIVE:
	gettimeofday(&STATE_SYNC(commit).stats.start, NULL);
	STATE_SYNC(commit).stats.ok = c->stats.commit_ok;
	STATE_SYNC(commit).stats.fail = c->stats.commit_fail;
	STATE_SYNC(commit).clientfd = clientfd;
	case COMMIT_STATE_MASTER:
	STATE_SYNC(commit).current =
	hashtable_iterate_limit(c->h, &tmp,
	STATE_SYNC(commit).current,
	CONFIG(general).commit_steps,
	cache_ct_commit_master);
	if (STATE_SYNC(commit).current < CONFIG(hashsize)) {
	STATE_SYNC(commit).state = COMMIT_STATE_MASTER;
	/* give it another step as soon as possible */
	write_evfd(STATE_SYNC(commit).evfd);
	return 1;
	}
	STATE_SYNC(commit).current = 0;
	STATE_SYNC(commit).state = COMMIT_STATE_RELATED;
	case COMMIT_STATE_RELATED:
	STATE_SYNC(commit).current =
	hashtable_iterate_limit(c->h, &tmp,
	STATE_SYNC(commit).current,
	CONFIG(general).commit_steps,
	cache_ct_commit_related);
	if (STATE_SYNC(commit).current < CONFIG(hashsize)) {
	STATE_SYNC(commit).state = COMMIT_STATE_RELATED;
	/* give it another step as soon as possible */
	write_evfd(STATE_SYNC(commit).evfd);
	return 1;
	}
	/* calculate the time that commit has taken */
	gettimeofday(&commit_stop, NULL);
	timersub(&commit_stop, &STATE_SYNC(commit).stats.start, &res);

	/* calculate new entries committed */
	commit_ok = c->stats.commit_ok - STATE_SYNC(commit).stats.ok;
	commit_fail =
	c->stats.commit_fail - STATE_SYNC(commit).stats.fail;

	/* log results */
	dlog(LOG_NOTICE, "Committed %u new entries", commit_ok);

	if (commit_fail)
	dlog(LOG_NOTICE, "%u entries can't be "
	"committed", commit_fail);

	dlog(LOG_NOTICE, "commit has taken %lu.%06lu seconds",
	res.tv_sec, res.tv_usec);

	/* prepare the state machine for new commits */
	STATE_SYNC(commit).current = 0;
	STATE_SYNC(commit).state = COMMIT_STATE_INACTIVE;

	return 0;
	}
	return 1;
	}

	static struct nethdr *
	cache_ct_build_msg(const struct cache_object *obj, int type)
	{
	return BUILD_NETMSG_FROM_CT(obj->ptr, type);
	}

	/* template to cache conntracks coming from the kernel. */
	struct cache_ops cache_sync_internal_ct_ops = {
	.hash = cache_ct_hash,
	.cmp = cache_ct_cmp,
	.alloc = cache_ct_alloc,
	.free = cache_ct_free,
	.copy = cache_ct_copy,
	.dump_step = cache_ct_dump_step,
	.commit = NULL,
	.build_msg = cache_ct_build_msg,
	};

	/* template to cache conntracks coming from the network. */
	struct cache_ops cache_sync_external_ct_ops = {
	.hash = cache_ct_hash,
	.cmp = cache_ct_cmp,
	.alloc = cache_ct_alloc,
	.free = cache_ct_free,
	.copy = cache_ct_copy,
	.dump_step = cache_ct_dump_step,
	.commit = cache_ct_commit,
	.build_msg = NULL,
	};

	/* template to cache conntracks for the statistics mode. */
	struct cache_ops cache_stats_ct_ops = {
	.hash = cache_ct_hash,
	.cmp = cache_ct_cmp,
	.alloc = cache_ct_alloc,
	.free = cache_ct_free,
	.copy = cache_ct_copy,
	.dump_step = cache_ct_dump_step,
	.commit = NULL,
	.build_msg = NULL,
	};