1 files changed, 1781 insertions, 0 deletions

diff --git a/contrib/bind9/lib/dns/sdlz.c b/contrib/bind9/lib/dns/sdlz.c
new file mode 100644
index 000000000000..2c6ba8d60de5
--- /dev/null
+++ b/contrib/bind9/lib/dns/sdlz.c
@@ -0,0 +1,1781 @@
+/*
+ * Portions Copyright (C) 2005-2007  Internet Systems Consortium, Inc. ("ISC")
+ * Portions Copyright (C) 1999-2001  Internet Software Consortium.
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
+ * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+ * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
+ * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+ * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
+ * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+ * PERFORMANCE OF THIS SOFTWARE.
+ */
+
+/*
+ * Copyright (C) 2002 Stichting NLnet, Netherlands, stichting@nlnet.nl.
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the
+ * above copyright notice and this permission notice appear in all
+ * copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND STICHTING NLNET
+ * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
+ * STICHTING NLNET BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
+ * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
+ * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE
+ * USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ * The development of Dynamically Loadable Zones (DLZ) for Bind 9 was
+ * conceived and contributed by Rob Butler.
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the
+ * above copyright notice and this permission notice appear in all
+ * copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND ROB BUTLER
+ * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
+ * ROB BUTLER BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
+ * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
+ * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE
+ * USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+/* $Id: sdlz.c,v 1.2.2.9 2007/02/14 23:45:43 marka Exp $ */
+
+/*! \file */
+
+#include <config.h>
+#include <string.h>
+
+#include <isc/buffer.h>
+#include <isc/lex.h>
+#include <isc/log.h>
+#include <isc/rwlock.h>
+#include <isc/string.h>
+#include <isc/util.h>
+#include <isc/magic.h>
+#include <isc/mem.h>
+#include <isc/once.h>
+#include <isc/print.h>
+#include <isc/region.h>
+
+#include <dns/callbacks.h>
+#include <dns/db.h>
+#include <dns/dbiterator.h>
+#include <dns/dlz.h>
+#include <dns/fixedname.h>
+#include <dns/log.h>
+#include <dns/rdata.h>
+#include <dns/rdatalist.h>
+#include <dns/rdataset.h>
+#include <dns/rdatasetiter.h>
+#include <dns/rdatatype.h>
+#include <dns/result.h>
+#include <dns/master.h>
+#include <dns/sdlz.h>
+#include <dns/types.h>
+
+#include "rdatalist_p.h"
+
+/*
+ * Private Types
+ */
+
+struct dns_sdlzimplementation {
+	const dns_sdlzmethods_t		*methods;
+	isc_mem_t			*mctx;
+	void				*driverarg;
+	unsigned int			flags;
+	isc_mutex_t			driverlock;
+	dns_dlzimplementation_t		*dlz_imp;
+};
+
+struct dns_sdlz_db {
+	/* Unlocked */
+	dns_db_t			common;
+	void				*dbdata;
+	dns_sdlzimplementation_t	*dlzimp;
+	isc_mutex_t			refcnt_lock;
+	/* Locked */
+	unsigned int			references;
+};
+
+struct dns_sdlzlookup {
+	/* Unlocked */
+	unsigned int			magic;
+	dns_sdlz_db_t			*sdlz;
+	ISC_LIST(dns_rdatalist_t)	lists;
+	ISC_LIST(isc_buffer_t)		buffers;
+	dns_name_t			*name;
+	ISC_LINK(dns_sdlzlookup_t)	link;
+	isc_mutex_t			lock;
+	dns_rdatacallbacks_t		callbacks;
+	/* Locked */
+	unsigned int			references;
+};
+
+typedef struct dns_sdlzlookup dns_sdlznode_t;
+
+struct dns_sdlzallnodes {
+	dns_dbiterator_t		common;
+	ISC_LIST(dns_sdlznode_t)	nodelist;
+	dns_sdlznode_t			*current;
+	dns_sdlznode_t			*origin;
+};
+
+typedef dns_sdlzallnodes_t sdlz_dbiterator_t;
+
+typedef struct sdlz_rdatasetiter {
+	dns_rdatasetiter_t		common;
+	dns_rdatalist_t			*current;
+} sdlz_rdatasetiter_t;
+
+
+#define SDLZDB_MAGIC		ISC_MAGIC('D', 'L', 'Z', 'S')
+
+/*
+ * Note that "impmagic" is not the first four bytes of the struct, so
+ * ISC_MAGIC_VALID cannot be used.
+ */
+
+#define VALID_SDLZDB(sdlzdb)	((sdlzdb) != NULL && \
+				 (sdlzdb)->common.impmagic == SDLZDB_MAGIC)
+
+#define SDLZLOOKUP_MAGIC	ISC_MAGIC('D','L','Z','L')
+#define VALID_SDLZLOOKUP(sdlzl)	ISC_MAGIC_VALID(sdlzl, SDLZLOOKUP_MAGIC)
+#define VALID_SDLZNODE(sdlzn)	VALID_SDLZLOOKUP(sdlzn)
+
+/* These values are taken from RFC 1537 */
+#define SDLZ_DEFAULT_REFRESH	(60 * 60 * 8)
+#define SDLZ_DEFAULT_RETRY	(60 * 60 * 2)
+#define SDLZ_DEFAULT_EXPIRE	(60 * 60 * 24 * 7)
+#define SDLZ_DEFAULT_MINIMUM	(60 * 60 * 24)
+
+/* This is a reasonable value */
+#define SDLZ_DEFAULT_TTL	(60 * 60 * 24)
+
+static int dummy;
+
+#define MAYBE_LOCK(imp) \
+	do { \
+		unsigned int flags = imp->flags; \
+		if ((flags & DNS_SDLZFLAG_THREADSAFE) == 0) \
+			LOCK(&imp->driverlock); \
+	} while (0)
+
+#define MAYBE_UNLOCK(imp) \
+	do { \
+		unsigned int flags = imp->flags; \
+		if ((flags & DNS_SDLZFLAG_THREADSAFE) == 0) \
+			UNLOCK(&imp->driverlock); \
+	} while (0)
+
+/*
+ * Forward references.  Try to keep these to a minimum.
+ */
+
+static void list_tordataset(dns_rdatalist_t *rdatalist,
+			    dns_db_t *db, dns_dbnode_t *node,
+			    dns_rdataset_t *rdataset);
+
+static void detachnode(dns_db_t *db, dns_dbnode_t **targetp);
+
+static void		dbiterator_destroy(dns_dbiterator_t **iteratorp);
+static isc_result_t	dbiterator_first(dns_dbiterator_t *iterator);
+static isc_result_t	dbiterator_last(dns_dbiterator_t *iterator);
+static isc_result_t	dbiterator_seek(dns_dbiterator_t *iterator,
+					dns_name_t *name);
+static isc_result_t	dbiterator_prev(dns_dbiterator_t *iterator);
+static isc_result_t	dbiterator_next(dns_dbiterator_t *iterator);
+static isc_result_t	dbiterator_current(dns_dbiterator_t *iterator,
+					   dns_dbnode_t **nodep,
+					   dns_name_t *name);
+static isc_result_t	dbiterator_pause(dns_dbiterator_t *iterator);
+static isc_result_t	dbiterator_origin(dns_dbiterator_t *iterator,
+					  dns_name_t *name);
+
+static dns_dbiteratormethods_t dbiterator_methods = {
+	dbiterator_destroy,
+	dbiterator_first,
+	dbiterator_last,
+	dbiterator_seek,
+	dbiterator_prev,
+	dbiterator_next,
+	dbiterator_current,
+	dbiterator_pause,
+	dbiterator_origin
+};
+
+/*
+ * Utility functions
+ */
+
+/*% Converts the input string to lowercase, in place. */
+
+static void
+dns_sdlz_tolower(char *str) {
+
+	unsigned int len = strlen(str);
+	unsigned int i;
+
+	for (i = 0; i < len; i++) {
+		if (str[i] >= 'A' && str[i] <= 'Z')
+			str[i] += 32;
+	}
+
+}
+
+static inline unsigned int
+initial_size(const char *data) {
+	unsigned int len = (strlen(data) / 64) + 1;
+	return (len * 64 + 64);
+}
+
+/*
+ * Rdataset Iterator Methods. These methods were "borrowed" from the SDB
+ * driver interface.  See the SDB driver interface documentation for more info.
+ */
+
+static void
+rdatasetiter_destroy(dns_rdatasetiter_t **iteratorp) {
+	sdlz_rdatasetiter_t *sdlziterator =
+		(sdlz_rdatasetiter_t *)(*iteratorp);
+
+	detachnode(sdlziterator->common.db, &sdlziterator->common.node);
+	isc_mem_put(sdlziterator->common.db->mctx, sdlziterator,
+		    sizeof(sdlz_rdatasetiter_t));
+	*iteratorp = NULL;
+}
+
+static isc_result_t
+rdatasetiter_first(dns_rdatasetiter_t *iterator) {
+	sdlz_rdatasetiter_t *sdlziterator = (sdlz_rdatasetiter_t *)iterator;
+	dns_sdlznode_t *sdlznode = (dns_sdlznode_t *)iterator->node;
+
+	if (ISC_LIST_EMPTY(sdlznode->lists))
+		return (ISC_R_NOMORE);
+	sdlziterator->current = ISC_LIST_HEAD(sdlznode->lists);
+	return (ISC_R_SUCCESS);
+}
+
+static isc_result_t
+rdatasetiter_next(dns_rdatasetiter_t *iterator) {
+	sdlz_rdatasetiter_t *sdlziterator = (sdlz_rdatasetiter_t *)iterator;
+
+	sdlziterator->current = ISC_LIST_NEXT(sdlziterator->current, link);
+	if (sdlziterator->current == NULL)
+		return (ISC_R_NOMORE);
+	else
+		return (ISC_R_SUCCESS);
+}
+
+static void
+rdatasetiter_current(dns_rdatasetiter_t *iterator, dns_rdataset_t *rdataset) {
+	sdlz_rdatasetiter_t *sdlziterator = (sdlz_rdatasetiter_t *)iterator;
+
+	list_tordataset(sdlziterator->current, iterator->db, iterator->node,
+			rdataset);
+}
+
+static dns_rdatasetitermethods_t rdatasetiter_methods = {
+	rdatasetiter_destroy,
+	rdatasetiter_first,
+	rdatasetiter_next,
+	rdatasetiter_current
+};
+
+/*
+ * DB routines. These methods were "borrowed" from the SDB driver interface.
+ * See the SDB driver interface documentation for more info.
+ */
+
+static void
+attach(dns_db_t *source, dns_db_t **targetp) {
+	dns_sdlz_db_t *sdlz = (dns_sdlz_db_t *) source;
+
+	REQUIRE(VALID_SDLZDB(sdlz));
+
+	LOCK(&sdlz->refcnt_lock);
+	REQUIRE(sdlz->references > 0);
+	sdlz->references++;
+	UNLOCK(&sdlz->refcnt_lock);
+
+	*targetp = source;
+}
+
+static void
+destroy(dns_sdlz_db_t *sdlz) {
+	isc_mem_t *mctx;
+	mctx = sdlz->common.mctx;
+
+	sdlz->common.magic = 0;
+	sdlz->common.impmagic = 0;
+
+	isc_mutex_destroy(&sdlz->refcnt_lock);
+
+	dns_name_free(&sdlz->common.origin, mctx);
+
+	isc_mem_put(mctx, sdlz, sizeof(dns_sdlz_db_t));
+	isc_mem_detach(&mctx);
+}
+
+static void
+detach(dns_db_t **dbp) {
+	dns_sdlz_db_t *sdlz = (dns_sdlz_db_t *)(*dbp);
+	isc_boolean_t need_destroy = ISC_FALSE;
+
+	REQUIRE(VALID_SDLZDB(sdlz));
+	LOCK(&sdlz->refcnt_lock);
+	REQUIRE(sdlz->references > 0);
+	sdlz->references--;
+	if (sdlz->references == 0)
+		need_destroy = ISC_TRUE;
+	UNLOCK(&sdlz->refcnt_lock);
+
+	if (need_destroy)
+		destroy(sdlz);
+
+	*dbp = NULL;
+}
+
+static isc_result_t
+beginload(dns_db_t *db, dns_addrdatasetfunc_t *addp, dns_dbload_t **dbloadp) {
+	UNUSED(db);
+	UNUSED(addp);
+	UNUSED(dbloadp);
+	return (ISC_R_NOTIMPLEMENTED);
+}
+
+static isc_result_t
+endload(dns_db_t *db, dns_dbload_t **dbloadp) {
+	UNUSED(db);
+	UNUSED(dbloadp);
+	return (ISC_R_NOTIMPLEMENTED);
+}
+
+static isc_result_t
+dump(dns_db_t *db, dns_dbversion_t *version, const char *filename,
+     dns_masterformat_t masterformat)
+{
+	UNUSED(db);
+	UNUSED(version);
+	UNUSED(filename);
+	UNUSED(masterformat);
+	return (ISC_R_NOTIMPLEMENTED);
+}
+
+static void
+currentversion(dns_db_t *db, dns_dbversion_t **versionp) {
+	REQUIRE(versionp != NULL && *versionp == NULL);
+
+	UNUSED(db);
+
+	*versionp = (void *) &dummy;
+	return;
+}
+
+static isc_result_t
+newversion(dns_db_t *db, dns_dbversion_t **versionp) {
+	UNUSED(db);
+	UNUSED(versionp);
+
+	return (ISC_R_NOTIMPLEMENTED);
+}
+
+static void
+attachversion(dns_db_t *db, dns_dbversion_t *source,
+	      dns_dbversion_t **targetp)
+{
+	REQUIRE(source != NULL && source == (void *) &dummy);
+
+	UNUSED(db);
+	UNUSED(source);
+	UNUSED(targetp);
+	*targetp = source;
+}
+
+static void
+closeversion(dns_db_t *db, dns_dbversion_t **versionp, isc_boolean_t commit) {
+	REQUIRE(versionp != NULL && *versionp == (void *) &dummy);
+	REQUIRE(commit == ISC_FALSE);
+
+	UNUSED(db);
+	UNUSED(commit);
+
+	*versionp = NULL;
+}
+
+static isc_result_t
+createnode(dns_sdlz_db_t *sdlz, dns_sdlznode_t **nodep) {
+	dns_sdlznode_t *node;
+	isc_result_t result;
+
+	node = isc_mem_get(sdlz->common.mctx, sizeof(dns_sdlznode_t));
+	if (node == NULL)
+		return (ISC_R_NOMEMORY);
+
+	node->sdlz = NULL;
+	attach((dns_db_t *)sdlz, (dns_db_t **)&node->sdlz);
+	ISC_LIST_INIT(node->lists);
+	ISC_LIST_INIT(node->buffers);
+	ISC_LINK_INIT(node, link);
+	node->name = NULL;
+	result = isc_mutex_init(&node->lock);
+	if (result != ISC_R_SUCCESS) {
+		UNEXPECTED_ERROR(__FILE__, __LINE__,
+				 "isc_mutex_init() failed: %s",
+				 isc_result_totext(result));
+		isc_mem_put(sdlz->common.mctx, node, sizeof(dns_sdlznode_t));
+		return (ISC_R_UNEXPECTED);
+	}
+	dns_rdatacallbacks_init(&node->callbacks);
+	node->references = 1;
+	node->magic = SDLZLOOKUP_MAGIC;
+
+	*nodep = node;
+	return (ISC_R_SUCCESS);
+}
+
+static void
+destroynode(dns_sdlznode_t *node) {
+	dns_rdatalist_t *list;
+	dns_rdata_t *rdata;
+	isc_buffer_t *b;
+	dns_sdlz_db_t *sdlz;
+	dns_db_t *db;
+	isc_mem_t *mctx;
+
+	sdlz = node->sdlz;
+	mctx = sdlz->common.mctx;
+
+	while (!ISC_LIST_EMPTY(node->lists)) {
+		list = ISC_LIST_HEAD(node->lists);
+		while (!ISC_LIST_EMPTY(list->rdata)) {
+			rdata = ISC_LIST_HEAD(list->rdata);
+			ISC_LIST_UNLINK(list->rdata, rdata, link);
+			isc_mem_put(mctx, rdata, sizeof(dns_rdata_t));
+		}
+		ISC_LIST_UNLINK(node->lists, list, link);
+		isc_mem_put(mctx, list, sizeof(dns_rdatalist_t));
+	}
+
+	while (!ISC_LIST_EMPTY(node->buffers)) {
+		b = ISC_LIST_HEAD(node->buffers);
+		ISC_LIST_UNLINK(node->buffers, b, link);
+		isc_buffer_free(&b);
+	}
+
+	if (node->name != NULL) {
+		dns_name_free(node->name, mctx);
+		isc_mem_put(mctx, node->name, sizeof(dns_name_t));
+	}
+	DESTROYLOCK(&node->lock);
+	node->magic = 0;
+	isc_mem_put(mctx, node, sizeof(dns_sdlznode_t));
+	db = &sdlz->common;
+	detach(&db);
+}
+
+static isc_result_t
+findnode(dns_db_t *db, dns_name_t *name, isc_boolean_t create,
+	 dns_dbnode_t **nodep)
+{
+	dns_sdlz_db_t *sdlz = (dns_sdlz_db_t *)db;
+	dns_sdlznode_t *node = NULL;
+	isc_result_t result;
+	isc_buffer_t b;
+	char namestr[DNS_NAME_MAXTEXT + 1];
+	isc_buffer_t b2;
+	char zonestr[DNS_NAME_MAXTEXT + 1];
+	isc_boolean_t isorigin;
+	dns_sdlzauthorityfunc_t authority;
+
+	REQUIRE(VALID_SDLZDB(sdlz));
+	REQUIRE(create == ISC_FALSE);
+	REQUIRE(nodep != NULL && *nodep == NULL);
+
+	UNUSED(name);
+	UNUSED(create);
+
+	isc_buffer_init(&b, namestr, sizeof(namestr));
+	if ((sdlz->dlzimp->flags & DNS_SDLZFLAG_RELATIVEOWNER) != 0) {
+		dns_name_t relname;
+		unsigned int labels;
+
+		labels = dns_name_countlabels(name) -
+			 dns_name_countlabels(&db->origin);
+		dns_name_init(&relname, NULL);
+		dns_name_getlabelsequence(name, 0, labels, &relname);
+		result = dns_name_totext(&relname, ISC_TRUE, &b);
+		if (result != ISC_R_SUCCESS)
+			return (result);
+	} else {
+		result = dns_name_totext(name, ISC_TRUE, &b);
+		if (result != ISC_R_SUCCESS)
+			return (result);
+	}
+	isc_buffer_putuint8(&b, 0);
+
+	isc_buffer_init(&b2, zonestr, sizeof(zonestr));
+	result = dns_name_totext(&sdlz->common.origin, ISC_TRUE, &b2);
+	if (result != ISC_R_SUCCESS)
+		return (result);
+	isc_buffer_putuint8(&b2, 0);
+
+	result = createnode(sdlz, &node);
+	if (result != ISC_R_SUCCESS)
+		return (result);
+
+	isorigin = dns_name_equal(name, &sdlz->common.origin);
+
+	/* make sure strings are always lowercase */
+	dns_sdlz_tolower(zonestr);
+	dns_sdlz_tolower(namestr);
+
+	MAYBE_LOCK(sdlz->dlzimp);
+
+	/* try to lookup the host (namestr) */
+	result = sdlz->dlzimp->methods->lookup(zonestr, namestr,
+					       sdlz->dlzimp->driverarg,
+					       sdlz->dbdata, node);
+
+	/*
+	 * if the host (namestr) was not found, try to lookup a
+	 * "wildcard" host.
+	 */
+	if (result != ISC_R_SUCCESS) {
+		result = sdlz->dlzimp->methods->lookup(zonestr, "*",
+						       sdlz->dlzimp->driverarg,
+						       sdlz->dbdata, node);
+	}
+
+	MAYBE_UNLOCK(sdlz->dlzimp);
+
+	if (result != ISC_R_SUCCESS && !isorigin) {
+		destroynode(node);
+		return (result);
+	}
+
+	if (isorigin && sdlz->dlzimp->methods->authority != NULL) {
+		MAYBE_LOCK(sdlz->dlzimp);
+		authority = sdlz->dlzimp->methods->authority;
+		result = (*authority)(zonestr, sdlz->dlzimp->driverarg,
+				      sdlz->dbdata, node);
+		MAYBE_UNLOCK(sdlz->dlzimp);
+		if (result != ISC_R_SUCCESS &&
+		    result != ISC_R_NOTIMPLEMENTED) {
+			destroynode(node);
+			return (result);
+		}
+	}
+
+	*nodep = node;
+	return (ISC_R_SUCCESS);
+}
+
+static isc_result_t
+findzonecut(dns_db_t *db, dns_name_t *name, unsigned int options,
+	    isc_stdtime_t now, dns_dbnode_t **nodep, dns_name_t *foundname,
+	    dns_rdataset_t *rdataset, dns_rdataset_t *sigrdataset)
+{
+	UNUSED(db);
+	UNUSED(name);
+	UNUSED(options);
+	UNUSED(now);
+	UNUSED(nodep);
+	UNUSED(foundname);
+	UNUSED(rdataset);
+	UNUSED(sigrdataset);
+
+	return (ISC_R_NOTIMPLEMENTED);
+}
+
+static void
+attachnode(dns_db_t *db, dns_dbnode_t *source, dns_dbnode_t **targetp) {
+	dns_sdlz_db_t *sdlz = (dns_sdlz_db_t *)db;
+	dns_sdlznode_t *node = (dns_sdlznode_t *)source;
+
+	REQUIRE(VALID_SDLZDB(sdlz));
+
+	UNUSED(sdlz);
+
+	LOCK(&node->lock);
+	INSIST(node->references > 0);
+	node->references++;
+	INSIST(node->references != 0);		/* Catch overflow. */
+	UNLOCK(&node->lock);
+
+	*targetp = source;
+}
+
+static void
+detachnode(dns_db_t *db, dns_dbnode_t **targetp) {
+	dns_sdlz_db_t *sdlz = (dns_sdlz_db_t *)db;
+	dns_sdlznode_t *node;
+	isc_boolean_t need_destroy = ISC_FALSE;
+
+	REQUIRE(VALID_SDLZDB(sdlz));
+	REQUIRE(targetp != NULL && *targetp != NULL);
+
+	UNUSED(sdlz);
+
+	node = (dns_sdlznode_t *)(*targetp);
+
+	LOCK(&node->lock);
+	INSIST(node->references > 0);
+	node->references--;
+	if (node->references == 0)
+		need_destroy = ISC_TRUE;
+	UNLOCK(&node->lock);
+
+	if (need_destroy)
+		destroynode(node);
+
+	*targetp = NULL;
+}
+
+static isc_result_t
+expirenode(dns_db_t *db, dns_dbnode_t *node, isc_stdtime_t now) {
+	UNUSED(db);
+	UNUSED(node);
+	UNUSED(now);
+	INSIST(0);
+	return (ISC_R_UNEXPECTED);
+}
+
+static void
+printnode(dns_db_t *db, dns_dbnode_t *node, FILE *out) {
+	UNUSED(db);
+	UNUSED(node);
+	UNUSED(out);
+	return;
+}
+
+static isc_result_t
+createiterator(dns_db_t *db, isc_boolean_t relative_names,
+	       dns_dbiterator_t **iteratorp)
+{
+	dns_sdlz_db_t *sdlz = (dns_sdlz_db_t *)db;
+	sdlz_dbiterator_t *sdlziter;
+	isc_result_t result;
+	isc_buffer_t b;
+	char zonestr[DNS_NAME_MAXTEXT + 1];
+
+	REQUIRE(VALID_SDLZDB(sdlz));
+
+	if (sdlz->dlzimp->methods->allnodes == NULL)
+		return (ISC_R_NOTIMPLEMENTED);
+
+	isc_buffer_init(&b, zonestr, sizeof(zonestr));
+	result = dns_name_totext(&sdlz->common.origin, ISC_TRUE, &b);
+	if (result != ISC_R_SUCCESS)
+		return (result);
+	isc_buffer_putuint8(&b, 0);
+
+	sdlziter = isc_mem_get(sdlz->common.mctx, sizeof(sdlz_dbiterator_t));
+	if (sdlziter == NULL)
+		return (ISC_R_NOMEMORY);
+
+	sdlziter->common.methods = &dbiterator_methods;
+	sdlziter->common.db = NULL;
+	dns_db_attach(db, &sdlziter->common.db);
+	sdlziter->common.relative_names = relative_names;
+	sdlziter->common.magic = DNS_DBITERATOR_MAGIC;
+	ISC_LIST_INIT(sdlziter->nodelist);
+	sdlziter->current = NULL;
+	sdlziter->origin = NULL;
+
+	/* make sure strings are always lowercase */
+	dns_sdlz_tolower(zonestr);
+
+	MAYBE_LOCK(sdlz->dlzimp);
+	result = sdlz->dlzimp->methods->allnodes(zonestr,
+						 sdlz->dlzimp->driverarg,
+						 sdlz->dbdata, sdlziter);
+	MAYBE_UNLOCK(sdlz->dlzimp);
+	if (result != ISC_R_SUCCESS) {
+		dns_dbiterator_t *iter = &sdlziter->common;
+		dbiterator_destroy(&iter);
+		return (result);
+	}
+
+	if (sdlziter->origin != NULL) {
+		ISC_LIST_UNLINK(sdlziter->nodelist, sdlziter->origin, link);
+		ISC_LIST_PREPEND(sdlziter->nodelist, sdlziter->origin, link);
+	}
+
+	*iteratorp = (dns_dbiterator_t *)sdlziter;
+
+	return (ISC_R_SUCCESS);
+}
+
+static isc_result_t
+findrdataset(dns_db_t *db, dns_dbnode_t *node, dns_dbversion_t *version,
+	     dns_rdatatype_t type, dns_rdatatype_t covers,
+	     isc_stdtime_t now, dns_rdataset_t *rdataset,
+	     dns_rdataset_t *sigrdataset)
+{
+	dns_rdatalist_t *list;
+	dns_sdlznode_t *sdlznode = (dns_sdlznode_t *)node;
+
+	REQUIRE(VALID_SDLZNODE(node));
+
+	UNUSED(db);
+	UNUSED(version);
+	UNUSED(covers);
+	UNUSED(now);
+	UNUSED(sigrdataset);
+
+	if (type == dns_rdatatype_sig || type == dns_rdatatype_rrsig)
+		return (ISC_R_NOTIMPLEMENTED);
+
+	list = ISC_LIST_HEAD(sdlznode->lists);
+	while (list != NULL) {
+		if (list->type == type)
+			break;
+		list = ISC_LIST_NEXT(list, link);
+	}
+	if (list == NULL)
+		return (ISC_R_NOTFOUND);
+
+	list_tordataset(list, db, node, rdataset);
+
+	return (ISC_R_SUCCESS);
+}
+
+static isc_result_t
+find(dns_db_t *db, dns_name_t *name, dns_dbversion_t *version,
+     dns_rdatatype_t type, unsigned int options, isc_stdtime_t now,
+     dns_dbnode_t **nodep, dns_name_t *foundname,
+     dns_rdataset_t *rdataset, dns_rdataset_t *sigrdataset)
+{
+	dns_sdlz_db_t *sdlz = (dns_sdlz_db_t *)db;
+	dns_dbnode_t *node = NULL;
+	dns_fixedname_t fname;
+	dns_rdataset_t xrdataset;
+	dns_name_t *xname;
+	unsigned int nlabels, olabels;
+	isc_result_t result;
+	unsigned int i;
+
+	REQUIRE(VALID_SDLZDB(sdlz));
+	REQUIRE(nodep == NULL || *nodep == NULL);
+	REQUIRE(version == NULL || version == (void *) &dummy);
+
+	UNUSED(options);
+	UNUSED(sdlz);
+
+	if (!dns_name_issubdomain(name, &db->origin))
+		return (DNS_R_NXDOMAIN);
+
+	olabels = dns_name_countlabels(&db->origin);
+	nlabels = dns_name_countlabels(name);
+
+	dns_fixedname_init(&fname);
+	xname = dns_fixedname_name(&fname);
+
+	if (rdataset == NULL) {
+		dns_rdataset_init(&xrdataset);
+		rdataset = &xrdataset;
+	}
+
+	result = DNS_R_NXDOMAIN;
+
+	for (i = olabels; i <= nlabels; i++) {
+		/*
+		 * Unless this is an explicit lookup at the origin, don't
+		 * look at the origin.
+		 */
+		if (i == olabels && i != nlabels)
+			continue;
+
+		/*
+		 * Look up the next label.
+		 */
+		dns_name_getlabelsequence(name, nlabels - i, i, xname);
+		result = findnode(db, xname, ISC_FALSE, &node);
+		if (result != ISC_R_SUCCESS) {
+			result = DNS_R_NXDOMAIN;
+			continue;
+		}
+
+		/*
+		 * Look for a DNAME at the current label, unless this is
+		 * the qname.
+		 */
+		if (i < nlabels) {
+			result = findrdataset(db, node, version,
+					      dns_rdatatype_dname,
+					      0, now, rdataset, sigrdataset);
+			if (result == ISC_R_SUCCESS) {
+				result = DNS_R_DNAME;
+				break;
+			}
+		}
+
+		/*
+		 * Look for an NS at the current label, unless this is the
+		 * origin or glue is ok.
+		 */
+		if (i != olabels && (options & DNS_DBFIND_GLUEOK) == 0) {
+			result = findrdataset(db, node, version,
+					      dns_rdatatype_ns,
+					      0, now, rdataset, sigrdataset);
+			if (result == ISC_R_SUCCESS) {
+				if (i == nlabels && type == dns_rdatatype_any)
+				{
+					result = DNS_R_ZONECUT;
+					dns_rdataset_disassociate(rdataset);
+					if (sigrdataset != NULL)
+						dns_rdataset_disassociate
+							(sigrdataset);
+				} else
+					result = DNS_R_DELEGATION;
+				break;
+			}
+		}
+
+		/*
+		 * If the current name is not the qname, add another label
+		 * and try again.
+		 */
+		if (i < nlabels) {
+			destroynode(node);
+			node = NULL;
+			continue;
+		}
+
+		/*
+		 * If we're looking for ANY, we're done.
+		 */
+		if (type == dns_rdatatype_any) {
+			result = ISC_R_SUCCESS;
+			break;
+		}
+
+		/*
+		 * Look for the qtype.
+		 */
+		result = findrdataset(db, node, version, type,
+				      0, now, rdataset, sigrdataset);
+		if (result == ISC_R_SUCCESS)
+			break;
+
+		/*
+		 * Look for a CNAME
+		 */
+		if (type != dns_rdatatype_cname) {
+			result = findrdataset(db, node, version,
+					      dns_rdatatype_cname,
+					      0, now, rdataset, sigrdataset);
+			if (result == ISC_R_SUCCESS) {
+				result = DNS_R_CNAME;
+				break;
+			}
+		}
+
+		result = DNS_R_NXRRSET;
+		break;
+	}
+
+	if (rdataset == &xrdataset && dns_rdataset_isassociated(rdataset))
+		dns_rdataset_disassociate(rdataset);
+
+	if (foundname != NULL) {
+		isc_result_t xresult;
+
+		xresult = dns_name_copy(xname, foundname, NULL);
+		if (xresult != ISC_R_SUCCESS) {
+			if (node != NULL)
+				destroynode(node);
+			if (dns_rdataset_isassociated(rdataset))
+				dns_rdataset_disassociate(rdataset);
+			return (DNS_R_BADDB);
+		}
+	}
+
+	if (nodep != NULL)
+		*nodep = node;
+	else if (node != NULL)
+		detachnode(db, &node);
+
+	return (result);
+}
+
+static isc_result_t
+allrdatasets(dns_db_t *db, dns_dbnode_t *node, dns_dbversion_t *version,
+	     isc_stdtime_t now, dns_rdatasetiter_t **iteratorp)
+{
+	sdlz_rdatasetiter_t *iterator;
+
+	REQUIRE(version == NULL || version == &dummy);
+
+	UNUSED(version);
+	UNUSED(now);
+
+	iterator = isc_mem_get(db->mctx, sizeof(sdlz_rdatasetiter_t));
+	if (iterator == NULL)
+		return (ISC_R_NOMEMORY);
+
+	iterator->common.magic = DNS_RDATASETITER_MAGIC;
+	iterator->common.methods = &rdatasetiter_methods;
+	iterator->common.db = db;
+	iterator->common.node = NULL;
+	attachnode(db, node, &iterator->common.node);
+	iterator->common.version = version;
+	iterator->common.now = now;
+
+	*iteratorp = (dns_rdatasetiter_t *)iterator;
+
+	return (ISC_R_SUCCESS);
+}
+
+static isc_result_t
+addrdataset(dns_db_t *db, dns_dbnode_t *node, dns_dbversion_t *version,
+	    isc_stdtime_t now, dns_rdataset_t *rdataset, unsigned int options,
+	    dns_rdataset_t *addedrdataset)
+{
+	UNUSED(db);
+	UNUSED(node);
+	UNUSED(version);
+	UNUSED(now);
+	UNUSED(rdataset);
+	UNUSED(options);
+	UNUSED(addedrdataset);
+
+	return (ISC_R_NOTIMPLEMENTED);
+}
+
+static isc_result_t
+subtractrdataset(dns_db_t *db, dns_dbnode_t *node, dns_dbversion_t *version,
+		 dns_rdataset_t *rdataset, unsigned int options,
+		 dns_rdataset_t *newrdataset)
+{
+	UNUSED(db);
+	UNUSED(node);
+	UNUSED(version);
+	UNUSED(rdataset);
+	UNUSED(options);
+	UNUSED(newrdataset);
+
+	return (ISC_R_NOTIMPLEMENTED);
+}
+
+static isc_result_t
+deleterdataset(dns_db_t *db, dns_dbnode_t *node, dns_dbversion_t *version,
+	       dns_rdatatype_t type, dns_rdatatype_t covers)
+{
+	UNUSED(db);
+	UNUSED(node);
+	UNUSED(version);
+	UNUSED(type);
+	UNUSED(covers);
+
+	return (ISC_R_NOTIMPLEMENTED);
+}
+
+static isc_boolean_t
+issecure(dns_db_t *db) {
+	UNUSED(db);
+
+	return (ISC_FALSE);
+}
+
+static unsigned int
+nodecount(dns_db_t *db) {
+	UNUSED(db);
+
+	return (0);
+}
+
+static isc_boolean_t
+ispersistent(dns_db_t *db) {
+	UNUSED(db);
+	return (ISC_TRUE);
+}
+
+static void
+overmem(dns_db_t *db, isc_boolean_t overmem) {
+	UNUSED(db);
+	UNUSED(overmem);
+}
+
+static void
+settask(dns_db_t *db, isc_task_t *task) {
+	UNUSED(db);
+	UNUSED(task);
+}
+
+
+static dns_dbmethods_t sdlzdb_methods = {
+	attach,
+	detach,
+	beginload,
+	endload,
+	dump,
+	currentversion,
+	newversion,
+	attachversion,
+	closeversion,
+	findnode,
+	find,
+	findzonecut,
+	attachnode,
+	detachnode,
+	expirenode,
+	printnode,
+	createiterator,
+	findrdataset,
+	allrdatasets,
+	addrdataset,
+	subtractrdataset,
+	deleterdataset,
+	issecure,
+	nodecount,
+	ispersistent,
+	overmem,
+	settask,
+	NULL,
+};
+
+/*
+ * Database Iterator Methods.  These methods were "borrowed" from the SDB
+ * driver interface.  See the SDB driver interface documentation for more info.
+ */
+
+static void
+dbiterator_destroy(dns_dbiterator_t **iteratorp) {
+	sdlz_dbiterator_t *sdlziter = (sdlz_dbiterator_t *)(*iteratorp);
+	dns_sdlz_db_t *sdlz = (dns_sdlz_db_t *)sdlziter->common.db;
+
+	while (!ISC_LIST_EMPTY(sdlziter->nodelist)) {
+		dns_sdlznode_t *node;
+		node = ISC_LIST_HEAD(sdlziter->nodelist);
+		ISC_LIST_UNLINK(sdlziter->nodelist, node, link);
+		destroynode(node);
+	}
+
+	dns_db_detach(&sdlziter->common.db);
+	isc_mem_put(sdlz->common.mctx, sdlziter, sizeof(sdlz_dbiterator_t));
+
+	*iteratorp = NULL;
+}
+
+static isc_result_t
+dbiterator_first(dns_dbiterator_t *iterator) {
+	sdlz_dbiterator_t *sdlziter = (sdlz_dbiterator_t *)iterator;
+
+	sdlziter->current = ISC_LIST_HEAD(sdlziter->nodelist);
+	if (sdlziter->current == NULL)
+		return (ISC_R_NOMORE);
+	else
+		return (ISC_R_SUCCESS);
+}
+
+static isc_result_t
+dbiterator_last(dns_dbiterator_t *iterator) {
+	sdlz_dbiterator_t *sdlziter = (sdlz_dbiterator_t *)iterator;
+
+	sdlziter->current = ISC_LIST_TAIL(sdlziter->nodelist);
+	if (sdlziter->current == NULL)
+		return (ISC_R_NOMORE);
+	else
+		return (ISC_R_SUCCESS);
+}
+
+static isc_result_t
+dbiterator_seek(dns_dbiterator_t *iterator, dns_name_t *name) {
+	sdlz_dbiterator_t *sdlziter = (sdlz_dbiterator_t *)iterator;
+
+	sdlziter->current = ISC_LIST_HEAD(sdlziter->nodelist);
+	while (sdlziter->current != NULL)
+		if (dns_name_equal(sdlziter->current->name, name))
+			return (ISC_R_SUCCESS);
+	return (ISC_R_NOTFOUND);
+}
+
+static isc_result_t
+dbiterator_prev(dns_dbiterator_t *iterator) {
+	sdlz_dbiterator_t *sdlziter = (sdlz_dbiterator_t *)iterator;
+
+	sdlziter->current = ISC_LIST_PREV(sdlziter->current, link);
+	if (sdlziter->current == NULL)
+		return (ISC_R_NOMORE);
+	else
+		return (ISC_R_SUCCESS);
+}
+
+static isc_result_t
+dbiterator_next(dns_dbiterator_t *iterator) {
+	sdlz_dbiterator_t *sdlziter = (sdlz_dbiterator_t *)iterator;
+
+	sdlziter->current = ISC_LIST_NEXT(sdlziter->current, link);
+	if (sdlziter->current == NULL)
+		return (ISC_R_NOMORE);
+	else
+		return (ISC_R_SUCCESS);
+}
+
+static isc_result_t
+dbiterator_current(dns_dbiterator_t *iterator, dns_dbnode_t **nodep,
+		   dns_name_t *name)
+{
+	sdlz_dbiterator_t *sdlziter = (sdlz_dbiterator_t *)iterator;
+
+	attachnode(iterator->db, sdlziter->current, nodep);
+	if (name != NULL)
+		return (dns_name_copy(sdlziter->current->name, name, NULL));
+	return (ISC_R_SUCCESS);
+}
+
+static isc_result_t
+dbiterator_pause(dns_dbiterator_t *iterator) {
+	UNUSED(iterator);
+	return (ISC_R_SUCCESS);
+}
+
+static isc_result_t
+dbiterator_origin(dns_dbiterator_t *iterator, dns_name_t *name) {
+	UNUSED(iterator);
+	return (dns_name_copy(dns_rootname, name, NULL));
+}
+
+/*
+ * Rdataset Methods. These methods were "borrowed" from the SDB driver
+ * interface.  See the SDB driver interface documentation for more info.
+ */
+
+static void
+disassociate(dns_rdataset_t *rdataset) {
+	dns_dbnode_t *node = rdataset->private5;
+	dns_sdlznode_t *sdlznode = (dns_sdlznode_t *) node;
+	dns_db_t *db = (dns_db_t *) sdlznode->sdlz;
+
+	detachnode(db, &node);
+	isc__rdatalist_disassociate(rdataset);
+}
+
+static void
+rdataset_clone(dns_rdataset_t *source, dns_rdataset_t *target) {
+	dns_dbnode_t *node = source->private5;
+	dns_sdlznode_t *sdlznode = (dns_sdlznode_t *) node;
+	dns_db_t *db = (dns_db_t *) sdlznode->sdlz;
+	dns_dbnode_t *tempdb = NULL;
+
+	isc__rdatalist_clone(source, target);
+	attachnode(db, node, &tempdb);
+	source->private5 = tempdb;
+}
+
+static dns_rdatasetmethods_t rdataset_methods = {
+	disassociate,
+	isc__rdatalist_first,
+	isc__rdatalist_next,
+	isc__rdatalist_current,
+	rdataset_clone,
+	isc__rdatalist_count,
+	isc__rdatalist_addnoqname,
+	isc__rdatalist_getnoqname,
+	NULL,
+	NULL,
+	NULL
+};
+
+static void
+list_tordataset(dns_rdatalist_t *rdatalist,
+		dns_db_t *db, dns_dbnode_t *node,
+		dns_rdataset_t *rdataset)
+{
+	/*
+	 * The sdlz rdataset is an rdatalist with some additions.
+	 *	- private1 & private2 are used by the rdatalist.
+	 *	- private3 & private 4 are unused.
+	 *	- private5 is the node.
+	 */
+
+	/* This should never fail. */
+	RUNTIME_CHECK(dns_rdatalist_tordataset(rdatalist, rdataset) ==
+		      ISC_R_SUCCESS);
+
+	rdataset->methods = &rdataset_methods;
+	dns_db_attachnode(db, node, &rdataset->private5);
+}
+
+/*
+ * SDLZ core methods. This is the core of the new DLZ functionality.
+ */
+
+/*%
+ * Build a 'bind' database driver structure to be returned by
+ * either the find zone or the allow zone transfer method.
+ * This method is only available in this source file, it is
+ * not made available anywhere else.
+ */
+
+static isc_result_t
+dns_sdlzcreateDBP(isc_mem_t *mctx, void *driverarg, void *dbdata,
+		  dns_name_t *name, dns_rdataclass_t rdclass, dns_db_t **dbp)
+{
+	isc_result_t result;
+	dns_sdlz_db_t *sdlzdb;
+	dns_sdlzimplementation_t *imp;
+
+	/* check that things are as we expect */
+	REQUIRE(dbp != NULL && *dbp == NULL);
+	REQUIRE(name != NULL);
+
+	imp = (dns_sdlzimplementation_t *) driverarg;
+
+	/* allocate and zero memory for driver structure */
+	sdlzdb = isc_mem_get(mctx, sizeof(dns_sdlz_db_t));
+	if (sdlzdb == NULL)
+		return (ISC_R_NOMEMORY);
+	memset(sdlzdb, 0, sizeof(dns_sdlz_db_t));
+
+	/* initialize and set origin */
+	dns_name_init(&sdlzdb->common.origin, NULL);
+	result = dns_name_dupwithoffsets(name, mctx, &sdlzdb->common.origin);
+	if (result != ISC_R_SUCCESS)
+		goto mem_cleanup;
+
+	/* initialize the reference count mutex */
+	result = isc_mutex_init(&sdlzdb->refcnt_lock);
+	if (result != ISC_R_SUCCESS)
+		goto name_cleanup;
+
+	/* set the rest of the database structure attributes */
+	sdlzdb->dlzimp = imp;
+	sdlzdb->common.methods = &sdlzdb_methods;
+	sdlzdb->common.attributes = 0;
+	sdlzdb->common.rdclass = rdclass;
+	sdlzdb->common.mctx = NULL;
+	sdlzdb->dbdata = dbdata;
+	sdlzdb->references = 1;
+
+	/* attach to the memory context */
+	isc_mem_attach(mctx, &sdlzdb->common.mctx);
+
+	/* mark structure as valid */
+	sdlzdb->common.magic = DNS_DB_MAGIC;
+	sdlzdb->common.impmagic = SDLZDB_MAGIC;
+	*dbp = (dns_db_t *) sdlzdb;
+
+	return (result);
+
+	/*
+	 * reference count mutex could not be initialized, clean up
+	 * name memory
+	 */
+ name_cleanup:
+	dns_name_free(&sdlzdb->common.origin, mctx);
+ mem_cleanup:
+	isc_mem_put(mctx, sdlzdb, sizeof(dns_sdlz_db_t));
+	return (result);
+}
+
+static isc_result_t
+dns_sdlzallowzonexfr(void *driverarg, void *dbdata, isc_mem_t *mctx,
+		     dns_rdataclass_t rdclass, dns_name_t *name,
+		     isc_sockaddr_t *clientaddr, dns_db_t **dbp)
+{
+	isc_buffer_t b;
+	isc_buffer_t b2;
+	char namestr[DNS_NAME_MAXTEXT + 1];
+	char clientstr[(sizeof "xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255")
+		       + 1];
+	isc_netaddr_t netaddr;
+	isc_result_t result;
+	dns_sdlzimplementation_t *imp;
+
+	/*
+	 * Perform checks to make sure data is as we expect it to be.
+	 */
+	REQUIRE(driverarg != NULL);
+	REQUIRE(name != NULL);
+	REQUIRE(clientaddr != NULL);
+	REQUIRE(dbp != NULL && *dbp == NULL);
+
+	imp = (dns_sdlzimplementation_t *) driverarg;
+
+	/* Convert DNS name to ascii text */
+	isc_buffer_init(&b, namestr, sizeof(namestr));
+	result = dns_name_totext(name, ISC_TRUE, &b);
+	if (result != ISC_R_SUCCESS)
+		return (result);
+	isc_buffer_putuint8(&b, 0);
+
+	/* convert client address to ascii text */
+	isc_buffer_init(&b2, clientstr, sizeof(clientstr));
+	isc_netaddr_fromsockaddr(&netaddr, clientaddr);
+	result = isc_netaddr_totext(&netaddr, &b2);
+	if (result != ISC_R_SUCCESS)
+		return (result);
+	isc_buffer_putuint8(&b2, 0);
+
+        /* make sure strings are always lowercase */
+	dns_sdlz_tolower(namestr);
+	dns_sdlz_tolower(clientstr);
+
+	/* Call SDLZ driver's find zone method */
+	if (imp->methods->allowzonexfr != NULL) {
+		MAYBE_LOCK(imp);
+		result = imp->methods->allowzonexfr(imp->driverarg, dbdata,
+						    namestr, clientstr);
+		MAYBE_UNLOCK(imp);
+		/*
+		 * if zone is supported and transfers allowed build a 'bind'
+		 * database driver
+		 */
+		if (result == ISC_R_SUCCESS)
+			result = dns_sdlzcreateDBP(mctx, driverarg, dbdata,
+						   name, rdclass, dbp);
+		return (result);
+	}
+
+	return (ISC_R_NOTIMPLEMENTED);
+}
+
+static isc_result_t
+dns_sdlzcreate(isc_mem_t *mctx, const char *dlzname, unsigned int argc,
+	       char *argv[], void *driverarg, void **dbdata)
+{
+	dns_sdlzimplementation_t *imp;
+	isc_result_t result = ISC_R_NOTFOUND;
+
+	/* Write debugging message to log */
+	isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+		      DNS_LOGMODULE_DLZ, ISC_LOG_DEBUG(2),
+		      "Loading SDLZ driver.");
+
+	/*
+	 * Performs checks to make sure data is as we expect it to be.
+	 */
+	REQUIRE(driverarg != NULL);
+	REQUIRE(dlzname != NULL);
+	REQUIRE(dbdata != NULL);
+	UNUSED(mctx);
+
+	imp = driverarg;
+
+	/* If the create method exists, call it. */
+	if (imp->methods->create != NULL) {
+		MAYBE_LOCK(imp);
+		result = imp->methods->create(dlzname, argc, argv,
+					      imp->driverarg, dbdata);
+		MAYBE_UNLOCK(imp);
+	}
+
+	/* Write debugging message to log */
+	if (result == ISC_R_SUCCESS) {
+		isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+			      DNS_LOGMODULE_DLZ, ISC_LOG_DEBUG(2),
+			      "SDLZ driver loaded successfully.");
+	} else {
+		isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+			      DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
+			      "SDLZ driver failed to load.");
+	}
+
+	return (result);
+}
+
+static void
+dns_sdlzdestroy(void *driverdata, void **dbdata)
+{
+
+	dns_sdlzimplementation_t *imp;
+
+	/* Write debugging message to log */
+	isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+		      DNS_LOGMODULE_DLZ, ISC_LOG_DEBUG(2),
+		      "Unloading SDLZ driver.");
+
+	imp = driverdata;
+
+	/* If the destroy method exists, call it. */
+	if (imp->methods->destroy != NULL) {
+		MAYBE_LOCK(imp);
+		imp->methods->destroy(imp->driverarg, dbdata);
+		MAYBE_UNLOCK(imp);
+	}
+}
+
+static isc_result_t
+dns_sdlzfindzone(void *driverarg, void *dbdata, isc_mem_t *mctx,
+		 dns_rdataclass_t rdclass, dns_name_t *name, dns_db_t **dbp)
+{
+	isc_buffer_t b;
+	char namestr[DNS_NAME_MAXTEXT + 1];
+	isc_result_t result;
+	dns_sdlzimplementation_t *imp;
+
+	/*
+	 * Perform checks to make sure data is as we expect it to be.
+	 */
+	REQUIRE(driverarg != NULL);
+	REQUIRE(name != NULL);
+	REQUIRE(dbp != NULL && *dbp == NULL);
+
+	imp = (dns_sdlzimplementation_t *) driverarg;
+
+	/* Convert DNS name to ascii text */
+	isc_buffer_init(&b, namestr, sizeof(namestr));
+	result = dns_name_totext(name, ISC_TRUE, &b);
+	if (result != ISC_R_SUCCESS)
+		return (result);
+	isc_buffer_putuint8(&b, 0);
+
+        /* make sure strings are always lowercase */
+	dns_sdlz_tolower(namestr);
+
+	/* Call SDLZ driver's find zone method */
+	MAYBE_LOCK(imp);
+	result = imp->methods->findzone(imp->driverarg, dbdata, namestr);
+	MAYBE_UNLOCK(imp);
+
+	/*
+	 * if zone is supported build a 'bind' database driver
+	 * structure to return
+	 */
+	if (result == ISC_R_SUCCESS)
+		result = dns_sdlzcreateDBP(mctx, driverarg, dbdata, name,
+					   rdclass, dbp);
+
+	return (result);
+}
+
+static dns_dlzmethods_t sdlzmethods = {
+	dns_sdlzcreate,
+	dns_sdlzdestroy,
+	dns_sdlzfindzone,
+	dns_sdlzallowzonexfr
+};
+
+/*
+ * Public functions.
+ */
+
+isc_result_t
+dns_sdlz_putrr(dns_sdlzlookup_t *lookup, const char *type, dns_ttl_t ttl,
+	       const char *data)
+{
+	dns_rdatalist_t *rdatalist;
+	dns_rdata_t *rdata;
+	dns_rdatatype_t typeval;
+	isc_consttextregion_t r;
+	isc_buffer_t b;
+	isc_buffer_t *rdatabuf = NULL;
+	isc_lex_t *lex;
+	isc_result_t result;
+	unsigned int size;
+	isc_mem_t *mctx;
+	dns_name_t *origin;
+
+	REQUIRE(VALID_SDLZLOOKUP(lookup));
+	REQUIRE(type != NULL);
+	REQUIRE(data != NULL);
+
+	mctx = lookup->sdlz->common.mctx;
+
+	r.base = type;
+	r.length = strlen(type);
+	result = dns_rdatatype_fromtext(&typeval, (void *) &r);
+	if (result != ISC_R_SUCCESS)
+		return (result);
+
+	rdatalist = ISC_LIST_HEAD(lookup->lists);
+	while (rdatalist != NULL) {
+		if (rdatalist->type == typeval)
+			break;
+		rdatalist = ISC_LIST_NEXT(rdatalist, link);
+	}
+
+	if (rdatalist == NULL) {
+		rdatalist = isc_mem_get(mctx, sizeof(dns_rdatalist_t));
+		if (rdatalist == NULL)
+			return (ISC_R_NOMEMORY);
+		rdatalist->rdclass = lookup->sdlz->common.rdclass;
+		rdatalist->type = typeval;
+		rdatalist->covers = 0;
+		rdatalist->ttl = ttl;
+		ISC_LIST_INIT(rdatalist->rdata);
+		ISC_LINK_INIT(rdatalist, link);
+		ISC_LIST_APPEND(lookup->lists, rdatalist, link);
+	} else
+		if (rdatalist->ttl != ttl)
+			return (DNS_R_BADTTL);
+
+	rdata = isc_mem_get(mctx, sizeof(dns_rdata_t));
+	if (rdata == NULL)
+		return (ISC_R_NOMEMORY);
+	dns_rdata_init(rdata);
+
+	if ((lookup->sdlz->dlzimp->flags & DNS_SDLZFLAG_RELATIVERDATA) != 0)
+		origin = &lookup->sdlz->common.origin;
+	else
+		origin = dns_rootname;
+
+	lex = NULL;
+	result = isc_lex_create(mctx, 64, &lex);
+	if (result != ISC_R_SUCCESS)
+		goto failure;
+
+	size = initial_size(data);
+	do {
+		isc_buffer_init(&b, data, strlen(data));
+		isc_buffer_add(&b, strlen(data));
+
+		result = isc_lex_openbuffer(lex, &b);
+		if (result != ISC_R_SUCCESS)
+			goto failure;
+
+		rdatabuf = NULL;
+		result = isc_buffer_allocate(mctx, &rdatabuf, size);
+		if (result != ISC_R_SUCCESS)
+			goto failure;
+
+		result = dns_rdata_fromtext(rdata, rdatalist->rdclass,
+					    rdatalist->type, lex,
+					    origin, ISC_FALSE,
+					    mctx, rdatabuf,
+					    &lookup->callbacks);
+		if (result != ISC_R_SUCCESS)
+			isc_buffer_free(&rdatabuf);
+		size *= 2;
+	} while (result == ISC_R_NOSPACE);
+
+	if (result != ISC_R_SUCCESS)
+		goto failure;
+
+	ISC_LIST_APPEND(rdatalist->rdata, rdata, link);
+	ISC_LIST_APPEND(lookup->buffers, rdatabuf, link);
+
+	if (lex != NULL)
+		isc_lex_destroy(&lex);
+
+	return (ISC_R_SUCCESS);
+
+ failure:
+ 	if (rdatabuf != NULL)
+		isc_buffer_free(&rdatabuf);
+	if (lex != NULL)
+		isc_lex_destroy(&lex);
+	isc_mem_put(mctx, rdata, sizeof(dns_rdata_t));
+
+	return (result);
+}
+
+isc_result_t
+dns_sdlz_putnamedrr(dns_sdlzallnodes_t *allnodes, const char *name,
+		    const char *type, dns_ttl_t ttl, const char *data)
+{
+	dns_name_t *newname, *origin;
+	dns_fixedname_t fnewname;
+	dns_sdlz_db_t *sdlz = (dns_sdlz_db_t *)allnodes->common.db;
+	dns_sdlznode_t *sdlznode;
+	isc_mem_t *mctx = sdlz->common.mctx;
+	isc_buffer_t b;
+	isc_result_t result;
+
+	dns_fixedname_init(&fnewname);
+	newname = dns_fixedname_name(&fnewname);
+
+	if ((sdlz->dlzimp->flags & DNS_SDLZFLAG_RELATIVERDATA) != 0)
+		origin = &sdlz->common.origin;
+	else
+		origin = dns_rootname;
+	isc_buffer_init(&b, name, strlen(name));
+	isc_buffer_add(&b, strlen(name));
+
+	result = dns_name_fromtext(newname, &b, origin, ISC_FALSE, NULL);
+	if (result != ISC_R_SUCCESS)
+		return (result);
+
+	if (allnodes->common.relative_names) {
+		/* All names are relative to the root */
+		unsigned int nlabels = dns_name_countlabels(newname);
+		dns_name_getlabelsequence(newname, 0, nlabels - 1, newname);
+	}
+
+	sdlznode = ISC_LIST_HEAD(allnodes->nodelist);
+	if (sdlznode == NULL || !dns_name_equal(sdlznode->name, newname)) {
+		sdlznode = NULL;
+		result = createnode(sdlz, &sdlznode);
+		if (result != ISC_R_SUCCESS)
+			return (result);
+		sdlznode->name = isc_mem_get(mctx, sizeof(dns_name_t));
+		if (sdlznode->name == NULL) {
+			destroynode(sdlznode);
+			return (ISC_R_NOMEMORY);
+		}
+		dns_name_init(sdlznode->name, NULL);
+		result = dns_name_dup(newname, mctx, sdlznode->name);
+		if (result != ISC_R_SUCCESS) {
+			isc_mem_put(mctx, sdlznode->name, sizeof(dns_name_t));
+			destroynode(sdlznode);
+			return (result);
+		}
+		ISC_LIST_PREPEND(allnodes->nodelist, sdlznode, link);
+		if (allnodes->origin == NULL &&
+		    dns_name_equal(newname, &sdlz->common.origin))
+			allnodes->origin = sdlznode;
+	}
+	return (dns_sdlz_putrr(sdlznode, type, ttl, data));
+
+}
+
+isc_result_t
+dns_sdlz_putsoa(dns_sdlzlookup_t *lookup, const char *mname, const char *rname,
+		isc_uint32_t serial)
+{
+	char str[2 * DNS_NAME_MAXTEXT + 5 * (sizeof("2147483647")) + 7];
+	int n;
+
+	REQUIRE(mname != NULL);
+	REQUIRE(rname != NULL);
+
+	n = snprintf(str, sizeof str, "%s %s %u %u %u %u %u",
+		     mname, rname, serial,
+		     SDLZ_DEFAULT_REFRESH, SDLZ_DEFAULT_RETRY,
+		     SDLZ_DEFAULT_EXPIRE, SDLZ_DEFAULT_MINIMUM);
+	if (n >= (int)sizeof(str) || n < 0)
+		return (ISC_R_NOSPACE);
+	return (dns_sdlz_putrr(lookup, "SOA", SDLZ_DEFAULT_TTL, str));
+}
+
+isc_result_t
+dns_sdlzregister(const char *drivername, const dns_sdlzmethods_t *methods,
+		 void *driverarg, unsigned int flags, isc_mem_t *mctx,
+		 dns_sdlzimplementation_t **sdlzimp)
+{
+
+	dns_sdlzimplementation_t *imp;
+	isc_result_t result;
+
+	/*
+	 * Performs checks to make sure data is as we expect it to be.
+	 */
+	REQUIRE(drivername != NULL);
+	REQUIRE(methods != NULL);
+	REQUIRE(methods->findzone != NULL);
+	REQUIRE(methods->lookup != NULL);
+	REQUIRE(mctx != NULL);
+	REQUIRE(sdlzimp != NULL && *sdlzimp == NULL);
+	REQUIRE((flags & ~(DNS_SDLZFLAG_RELATIVEOWNER |
+			   DNS_SDLZFLAG_RELATIVERDATA |
+			   DNS_SDLZFLAG_THREADSAFE)) == 0);
+
+	/* Write debugging message to log */
+	isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+		      DNS_LOGMODULE_DLZ, ISC_LOG_DEBUG(2),
+		      "Registering SDLZ driver '%s'", drivername);
+
+	/*
+	 * Allocate memory for a sdlz_implementation object.  Error if
+	 * we cannot.
+	 */
+	imp = isc_mem_get(mctx, sizeof(dns_sdlzimplementation_t));
+	if (imp == NULL)
+		return (ISC_R_NOMEMORY);
+
+	/* Make sure memory region is set to all 0's */
+	memset(imp, 0, sizeof(dns_sdlzimplementation_t));
+
+	/* Store the data passed into this method */
+	imp->methods = methods;
+	imp->driverarg = driverarg;
+	imp->flags = flags;
+	imp->mctx = NULL;
+
+	/* attach the new sdlz_implementation object to a memory context */
+	isc_mem_attach(mctx, &imp->mctx);
+
+	/*
+	 * initialize the driver lock, error if we cannot
+	 * (used if a driver does not support multiple threads)
+	 */
+	result = isc_mutex_init(&imp->driverlock);
+	if (result != ISC_R_SUCCESS) {
+		UNEXPECTED_ERROR(__FILE__, __LINE__,
+				 "isc_mutex_init() failed: %s",
+				 isc_result_totext(result));
+		goto cleanup_mctx;
+	}
+
+	imp->dlz_imp = NULL;
+
+	/*
+	 * register the DLZ driver.  Pass in our "extra" sdlz information as
+	 * a driverarg.  (that's why we stored the passed in driver arg in our
+	 * sdlz_implementation structure)  Also, store the dlz_implementation
+	 * structure in our sdlz_implementation.
+	 */
+	result = dns_dlzregister(drivername, &sdlzmethods, imp, mctx,
+				 &imp->dlz_imp);
+
+	/* if registration fails, cleanup and get outta here. */
+	if (result != ISC_R_SUCCESS)
+		goto cleanup_mutex;
+
+	*sdlzimp = imp;
+
+	return (ISC_R_SUCCESS);
+
+ cleanup_mutex:
+	/* destroy the driver lock, we don't need it anymore */
+	DESTROYLOCK(&imp->driverlock);
+
+ cleanup_mctx:
+	/*
+	 * return the memory back to the available memory pool and
+	 * remove it from the memory context.
+	 */
+	isc_mem_put(mctx, imp, sizeof(dns_sdlzimplementation_t));
+	isc_mem_detach(&mctx);
+	return (result);
+}
+
+void
+dns_sdlzunregister(dns_sdlzimplementation_t **sdlzimp) {
+	dns_sdlzimplementation_t *imp;
+	isc_mem_t *mctx;
+
+	/* Write debugging message to log */
+	isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+		      DNS_LOGMODULE_DLZ, ISC_LOG_DEBUG(2),
+		      "Unregistering SDLZ driver.");
+
+	/*
+	 * Performs checks to make sure data is as we expect it to be.
+	 */
+	REQUIRE(sdlzimp != NULL && *sdlzimp != NULL);
+
+	imp = *sdlzimp;
+
+	/* Unregister the DLZ driver implementation */
+	dns_dlzunregister(&imp->dlz_imp);
+
+	/* destroy the driver lock, we don't need it anymore */
+	DESTROYLOCK(&imp->driverlock);
+
+	mctx = imp->mctx;
+
+	/*
+	 * return the memory back to the available memory pool and
+	 * remove it from the memory context.
+	 */
+	isc_mem_put(mctx, imp, sizeof(dns_sdlzimplementation_t));
+	isc_mem_detach(&mctx);
+
+	*sdlzimp = NULL;
+}