path: root/lib/dns/ecdb.c

/*
 * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
 *
 * SPDX-License-Identifier: MPL-2.0
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0.  If a copy of the MPL was not distributed with this
 * file, you can obtain one at https://mozilla.org/MPL/2.0/.
 *
 * See the COPYRIGHT file distributed with this work for additional
 * information regarding copyright ownership.
 */

#include <stdbool.h>

#include <isc/mem.h>
#include <isc/mutex.h>
#include <isc/refcount.h>
#include <isc/result.h>
#include <isc/util.h>

#include <dns/db.h>
#include <dns/ecdb.h>
#include <dns/rdata.h>
#include <dns/rdataset.h>
#include <dns/rdatasetiter.h>
#include <dns/rdataslab.h>

#define ECDB_MAGIC     ISC_MAGIC('E', 'C', 'D', 'B')
#define VALID_ECDB(db) ((db) != NULL && (db)->common.impmagic == ECDB_MAGIC)

#define ECDBNODE_MAGIC	      ISC_MAGIC('E', 'C', 'D', 'N')
#define VALID_ECDBNODE(ecdbn) ISC_MAGIC_VALID(ecdbn, ECDBNODE_MAGIC)

/*%
 * The 'ephemeral' cache DB (ecdb) implementation.  An ecdb just provides
 * temporary storage for ongoing name resolution with the common DB interfaces.
 * It actually doesn't cache anything.  The implementation expects any stored
 * data is released within a short period, and does not care about the
 * scalability in terms of the number of nodes.
 */

typedef struct dns_ecdb {
	/* Unlocked */
	dns_db_t common;
	isc_mutex_t lock;

	/* Protected by atomics */
	isc_refcount_t references;

	/* Locked */
	ISC_LIST(struct dns_ecdbnode) nodes;
} dns_ecdb_t;

typedef struct dns_ecdbnode {
	/* Unlocked */
	unsigned int magic;
	isc_mutex_t lock;
	dns_ecdb_t *ecdb;
	dns_name_t name;
	ISC_LINK(struct dns_ecdbnode) link;

	/* Locked */
	ISC_LIST(struct rdatasetheader) rdatasets;

	/* Protected by atomics */
	isc_refcount_t references;
} dns_ecdbnode_t;

typedef struct rdatasetheader {
	dns_rdatatype_t type;
	dns_ttl_t ttl;
	dns_trust_t trust;
	dns_rdatatype_t covers;
	unsigned int attributes;

	ISC_LINK(struct rdatasetheader) link;
} rdatasetheader_t;

/* Copied from rbtdb.c */
#define RDATASET_ATTR_NXDOMAIN 0x0010
#define RDATASET_ATTR_NEGATIVE 0x0100
#define NXDOMAIN(header)       (((header)->attributes & RDATASET_ATTR_NXDOMAIN) != 0)
#define NEGATIVE(header)       (((header)->attributes & RDATASET_ATTR_NEGATIVE) != 0)

static isc_result_t
dns_ecdb_create(isc_mem_t *mctx, const dns_name_t *origin, dns_dbtype_t type,
		dns_rdataclass_t rdclass, unsigned int argc, char *argv[],
		void *driverarg, dns_db_t **dbp);

static void
rdataset_disassociate(dns_rdataset_t *rdataset);
static isc_result_t
rdataset_first(dns_rdataset_t *rdataset);
static isc_result_t
rdataset_next(dns_rdataset_t *rdataset);
static void
rdataset_current(dns_rdataset_t *rdataset, dns_rdata_t *rdata);
static void
rdataset_clone(dns_rdataset_t *source, dns_rdataset_t *target);
static unsigned int
rdataset_count(dns_rdataset_t *rdataset);
static void
rdataset_settrust(dns_rdataset_t *rdataset, dns_trust_t trust);

static dns_rdatasetmethods_t rdataset_methods = {
	rdataset_disassociate,
	rdataset_first,
	rdataset_next,
	rdataset_current,
	rdataset_clone,
	rdataset_count,
	NULL,		   /* addnoqname */
	NULL,		   /* getnoqname */
	NULL,		   /* addclosest */
	NULL,		   /* getclosest */
	rdataset_settrust, /* settrust */
	NULL,		   /* expire */
	NULL,		   /* clearprefetch */
	NULL,		   /* setownercase */
	NULL,		   /* getownercase */
	NULL		   /* addglue */
};

typedef struct ecdb_rdatasetiter {
	dns_rdatasetiter_t common;
	rdatasetheader_t *current;
} ecdb_rdatasetiter_t;

static void
rdatasetiter_destroy(dns_rdatasetiter_t **iteratorp);
static isc_result_t
rdatasetiter_first(dns_rdatasetiter_t *iterator);
static isc_result_t
rdatasetiter_next(dns_rdatasetiter_t *iterator);
static void
rdatasetiter_current(dns_rdatasetiter_t *iterator, dns_rdataset_t *rdataset);

static dns_rdatasetitermethods_t rdatasetiter_methods = {
	rdatasetiter_destroy, rdatasetiter_first, rdatasetiter_next,
	rdatasetiter_current
};

isc_result_t
dns_ecdb_register(isc_mem_t *mctx, dns_dbimplementation_t **dbimp) {
	REQUIRE(mctx != NULL);
	REQUIRE(dbimp != NULL && *dbimp == NULL);

	return (dns_db_register("ecdb", dns_ecdb_create, NULL, mctx, dbimp));
}

void
dns_ecdb_unregister(dns_dbimplementation_t **dbimp) {
	REQUIRE(dbimp != NULL && *dbimp != NULL);

	dns_db_unregister(dbimp);
}

/*%
 * DB routines
 */

static void
attach(dns_db_t *source, dns_db_t **targetp) {
	dns_ecdb_t *ecdb = (dns_ecdb_t *)source;

	REQUIRE(VALID_ECDB(ecdb));
	REQUIRE(targetp != NULL && *targetp == NULL);

	isc_refcount_increment(&ecdb->references);

	*targetp = source;
}

static void
destroy_ecdb(dns_ecdb_t *ecdb) {
	if (isc_refcount_decrement(&ecdb->references) == 1) {
		isc_refcount_destroy(&ecdb->references);

		INSIST(ISC_LIST_EMPTY(ecdb->nodes));

		if (dns_name_dynamic(&ecdb->common.origin)) {
			dns_name_free(&ecdb->common.origin, ecdb->common.mctx);
		}

		isc_mutex_destroy(&ecdb->lock);

		ecdb->common.impmagic = 0;
		ecdb->common.magic = 0;

		isc_mem_putanddetach(&ecdb->common.mctx, ecdb, sizeof(*ecdb));
	}
}

static void
detach(dns_db_t **dbp) {
	dns_ecdb_t *ecdb;

	REQUIRE(dbp != NULL);
	ecdb = (dns_ecdb_t *)*dbp;
	REQUIRE(VALID_ECDB(ecdb));

	*dbp = NULL;

	destroy_ecdb(ecdb);
}

static void
attachnode(dns_db_t *db, dns_dbnode_t *source, dns_dbnode_t **targetp) {
	dns_ecdb_t *ecdb = (dns_ecdb_t *)db;
	dns_ecdbnode_t *node = (dns_ecdbnode_t *)source;

	REQUIRE(VALID_ECDB(ecdb));
	REQUIRE(VALID_ECDBNODE(node));
	REQUIRE(targetp != NULL && *targetp == NULL);

	isc_refcount_increment(&node->references);
	isc_refcount_increment(&node->references);

	*targetp = node;
}

static void
destroynode(dns_ecdbnode_t *node) {
	isc_mem_t *mctx;
	dns_ecdb_t *ecdb = node->ecdb;
	rdatasetheader_t *header;

	mctx = ecdb->common.mctx;

	LOCK(&ecdb->lock);
	ISC_LIST_UNLINK(ecdb->nodes, node, link);
	UNLOCK(&ecdb->lock);

	dns_name_free(&node->name, mctx);

	while ((header = ISC_LIST_HEAD(node->rdatasets)) != NULL) {
		unsigned int headersize;

		ISC_LIST_UNLINK(node->rdatasets, header, link);
		headersize = dns_rdataslab_size((unsigned char *)header,
						sizeof(*header));
		isc_mem_put(mctx, header, headersize);
	}

	isc_mutex_destroy(&node->lock);
	isc_refcount_destroy(&node->references);

	node->magic = 0;
	isc_mem_put(mctx, node, sizeof(*node));

	destroy_ecdb(ecdb);
}

static void
detachnode(dns_db_t *db, dns_dbnode_t **nodep) {
	dns_ecdb_t *ecdb = (dns_ecdb_t *)db;
	dns_ecdbnode_t *node;

	REQUIRE(VALID_ECDB(ecdb));
	REQUIRE(nodep != NULL);
	node = (dns_ecdbnode_t *)*nodep;
	REQUIRE(VALID_ECDBNODE(node));
	*nodep = NULL;

	if (isc_refcount_decrement(&node->references) == 1) {
		destroynode(node);
	}
}

static isc_result_t
find(dns_db_t *db, const 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_ecdb_t *ecdb = (dns_ecdb_t *)db;

	REQUIRE(VALID_ECDB(ecdb));

	UNUSED(name);
	UNUSED(version);
	UNUSED(type);
	UNUSED(options);
	UNUSED(now);
	UNUSED(nodep);
	UNUSED(foundname);
	UNUSED(rdataset);
	UNUSED(sigrdataset);

	return (ISC_R_NOTFOUND);
}

static isc_result_t
findzonecut(dns_db_t *db, const dns_name_t *name, unsigned int options,
	    isc_stdtime_t now, dns_dbnode_t **nodep, dns_name_t *foundname,
	    dns_name_t *dcname, dns_rdataset_t *rdataset,
	    dns_rdataset_t *sigrdataset) {
	dns_ecdb_t *ecdb = (dns_ecdb_t *)db;

	REQUIRE(VALID_ECDB(ecdb));

	UNUSED(name);
	UNUSED(options);
	UNUSED(now);
	UNUSED(nodep);
	UNUSED(foundname);
	UNUSED(dcname);
	UNUSED(rdataset);
	UNUSED(sigrdataset);

	return (ISC_R_NOTFOUND);
}

static isc_result_t
findnode(dns_db_t *db, const dns_name_t *name, bool create,
	 dns_dbnode_t **nodep) {
	dns_ecdb_t *ecdb = (dns_ecdb_t *)db;
	isc_mem_t *mctx;
	dns_ecdbnode_t *node;

	REQUIRE(VALID_ECDB(ecdb));
	REQUIRE(nodep != NULL && *nodep == NULL);

	UNUSED(name);

	if (create != true) {
		/* an 'ephemeral' node is never reused. */
		return (ISC_R_NOTFOUND);
	}

	mctx = ecdb->common.mctx;
	node = isc_mem_get(mctx, sizeof(*node));

	isc_mutex_init(&node->lock);

	dns_name_init(&node->name, NULL);
	dns_name_dup(name, mctx, &node->name);

	isc_refcount_init(&node->references, 1);
	ISC_LIST_INIT(node->rdatasets);

	ISC_LINK_INIT(node, link);

	isc_refcount_increment(&ecdb->references);
	node->ecdb = ecdb;

	LOCK(&ecdb->lock);
	ISC_LIST_APPEND(ecdb->nodes, node, link);
	UNLOCK(&ecdb->lock);

	node->magic = ECDBNODE_MAGIC;

	*nodep = node;

	return (ISC_R_SUCCESS);
}

static void
bind_rdataset(dns_ecdb_t *ecdb, dns_ecdbnode_t *node, rdatasetheader_t *header,
	      dns_rdataset_t *rdataset) {
	unsigned char *raw;

	/*
	 * Caller must be holding the node lock.
	 */

	REQUIRE(!dns_rdataset_isassociated(rdataset));

	rdataset->methods = &rdataset_methods;
	rdataset->rdclass = ecdb->common.rdclass;
	rdataset->type = header->type;
	rdataset->covers = header->covers;
	rdataset->ttl = header->ttl;
	rdataset->trust = header->trust;
	if (NXDOMAIN(header)) {
		rdataset->attributes |= DNS_RDATASETATTR_NXDOMAIN;
	}
	if (NEGATIVE(header)) {
		rdataset->attributes |= DNS_RDATASETATTR_NEGATIVE;
	}

	rdataset->private1 = ecdb;
	rdataset->private2 = node;
	raw = (unsigned char *)header + sizeof(*header);
	rdataset->private3 = raw;
	rdataset->count = 0;

	/*
	 * Reset iterator state.
	 */
	rdataset->privateuint4 = 0;
	rdataset->private5 = NULL;

	isc_refcount_increment(&node->references);
}

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) {
	dns_ecdb_t *ecdb = (dns_ecdb_t *)db;
	isc_region_t r;
	isc_result_t result = ISC_R_SUCCESS;
	isc_mem_t *mctx;
	dns_ecdbnode_t *ecdbnode = (dns_ecdbnode_t *)node;
	rdatasetheader_t *header;

	REQUIRE(VALID_ECDB(ecdb));
	REQUIRE(VALID_ECDBNODE(ecdbnode));

	UNUSED(version);
	UNUSED(now);
	UNUSED(options);

	mctx = ecdb->common.mctx;

	LOCK(&ecdbnode->lock);

	/*
	 * Sanity check: this implementation does not allow overriding an
	 * existing rdataset of the same type.
	 */
	for (header = ISC_LIST_HEAD(ecdbnode->rdatasets); header != NULL;
	     header = ISC_LIST_NEXT(header, link))
	{
		INSIST(header->type != rdataset->type ||
		       header->covers != rdataset->covers);
	}

	result = dns_rdataslab_fromrdataset(rdataset, mctx, &r,
					    sizeof(rdatasetheader_t));
	if (result != ISC_R_SUCCESS) {
		goto unlock;
	}

	header = (rdatasetheader_t *)r.base;
	header->type = rdataset->type;
	header->ttl = rdataset->ttl;
	header->trust = rdataset->trust;
	header->covers = rdataset->covers;
	header->attributes = 0;
	if ((rdataset->attributes & DNS_RDATASETATTR_NXDOMAIN) != 0) {
		header->attributes |= RDATASET_ATTR_NXDOMAIN;
	}
	if ((rdataset->attributes & DNS_RDATASETATTR_NEGATIVE) != 0) {
		header->attributes |= RDATASET_ATTR_NEGATIVE;
	}
	ISC_LINK_INIT(header, link);
	ISC_LIST_APPEND(ecdbnode->rdatasets, header, link);

	if (addedrdataset == NULL) {
		goto unlock;
	}

	bind_rdataset(ecdb, ecdbnode, header, addedrdataset);

unlock:
	UNLOCK(&ecdbnode->lock);

	return (result);
}

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_result_t
createiterator(dns_db_t *db, unsigned int options,
	       dns_dbiterator_t **iteratorp) {
	UNUSED(db);
	UNUSED(options);
	UNUSED(iteratorp);

	return (ISC_R_NOTIMPLEMENTED);
}

static isc_result_t
allrdatasets(dns_db_t *db, dns_dbnode_t *node, dns_dbversion_t *version,
	     unsigned int options, isc_stdtime_t now,
	     dns_rdatasetiter_t **iteratorp) {
	dns_ecdb_t *ecdb = (dns_ecdb_t *)db;
	dns_ecdbnode_t *ecdbnode = (dns_ecdbnode_t *)node;
	isc_mem_t *mctx;
	ecdb_rdatasetiter_t *iterator;

	REQUIRE(VALID_ECDB(ecdb));
	REQUIRE(VALID_ECDBNODE(ecdbnode));

	mctx = ecdb->common.mctx;

	iterator = isc_mem_get(mctx, sizeof(ecdb_rdatasetiter_t));

	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.options = options;
	iterator->common.now = now;

	*iteratorp = (dns_rdatasetiter_t *)iterator;

	return (ISC_R_SUCCESS);
}

static dns_dbmethods_t ecdb_methods = {
	attach,
	detach,
	NULL, /* beginload */
	NULL, /* endload */
	NULL, /* serialize */
	NULL, /* dump */
	NULL, /* currentversion */
	NULL, /* newversion */
	NULL, /* attachversion */
	NULL, /* closeversion */
	findnode,
	find,
	findzonecut,
	attachnode,
	detachnode,
	NULL,		/* expirenode */
	NULL,		/* printnode */
	createiterator, /* createiterator */
	NULL,		/* findrdataset */
	allrdatasets,
	addrdataset,
	NULL, /* subtractrdataset */
	deleterdataset,
	NULL, /* issecure */
	NULL, /* nodecount */
	NULL, /* ispersistent */
	NULL, /* overmem */
	NULL, /* settask */
	NULL, /* getoriginnode */
	NULL, /* transfernode */
	NULL, /* getnsec3parameters */
	NULL, /* findnsec3node */
	NULL, /* setsigningtime */
	NULL, /* getsigningtime */
	NULL, /* resigned */
	NULL, /* isdnssec */
	NULL, /* getrrsetstats */
	NULL, /* rpz_attach */
	NULL, /* rpz_ready */
	NULL, /* findnodeext */
	NULL, /* findext */
	NULL, /* setcachestats */
	NULL, /* hashsize */
	NULL, /* nodefullname */
	NULL, /* getsize */
	NULL, /* setservestalettl */
	NULL, /* getservestalettl */
	NULL  /* setgluecachestats */
};

static isc_result_t
dns_ecdb_create(isc_mem_t *mctx, const dns_name_t *origin, dns_dbtype_t type,
		dns_rdataclass_t rdclass, unsigned int argc, char *argv[],
		void *driverarg, dns_db_t **dbp) {
	dns_ecdb_t *ecdb;
	isc_result_t result;

	REQUIRE(mctx != NULL);
	REQUIRE(origin == dns_rootname);
	REQUIRE(type == dns_dbtype_cache);
	REQUIRE(dbp != NULL && *dbp == NULL);

	UNUSED(argc);
	UNUSED(argv);
	UNUSED(driverarg);

	ecdb = isc_mem_get(mctx, sizeof(*ecdb));

	ecdb->common.attributes = DNS_DBATTR_CACHE;
	ecdb->common.rdclass = rdclass;
	ecdb->common.methods = &ecdb_methods;
	dns_name_init(&ecdb->common.origin, NULL);
	result = dns_name_dupwithoffsets(origin, mctx, &ecdb->common.origin);
	if (result != ISC_R_SUCCESS) {
		isc_mem_put(mctx, ecdb, sizeof(*ecdb));
		return (result);
	}

	isc_mutex_init(&ecdb->lock);

	isc_refcount_init(&ecdb->references, 1);
	ISC_LIST_INIT(ecdb->nodes);

	ecdb->common.mctx = NULL;
	isc_mem_attach(mctx, &ecdb->common.mctx);
	ecdb->common.impmagic = ECDB_MAGIC;
	ecdb->common.magic = DNS_DB_MAGIC;

	*dbp = (dns_db_t *)ecdb;

	return (ISC_R_SUCCESS);
}

/*%
 * Rdataset Methods
 */

static void
rdataset_disassociate(dns_rdataset_t *rdataset) {
	dns_db_t *db = rdataset->private1;
	dns_dbnode_t *node = rdataset->private2;

	dns_db_detachnode(db, &node);
}

static isc_result_t
rdataset_first(dns_rdataset_t *rdataset) {
	unsigned char *raw = rdataset->private3;
	unsigned int count;

	count = raw[0] * 256 + raw[1];
	if (count == 0) {
		rdataset->private5 = NULL;
		return (ISC_R_NOMORE);
	}
#if DNS_RDATASET_FIXED
	raw += 2 + (4 * count);
#else  /* if DNS_RDATASET_FIXED */
	raw += 2;
#endif /* if DNS_RDATASET_FIXED */
	/*
	 * The privateuint4 field is the number of rdata beyond the cursor
	 * position, so we decrement the total count by one before storing
	 * it.
	 */
	count--;
	rdataset->privateuint4 = count;
	rdataset->private5 = raw;

	return (ISC_R_SUCCESS);
}

static isc_result_t
rdataset_next(dns_rdataset_t *rdataset) {
	unsigned int count;
	unsigned int length;
	unsigned char *raw;

	count = rdataset->privateuint4;
	if (count == 0) {
		return (ISC_R_NOMORE);
	}
	count--;
	rdataset->privateuint4 = count;
	raw = rdataset->private5;
	length = raw[0] * 256 + raw[1];
#if DNS_RDATASET_FIXED
	raw += length + 4;
#else  /* if DNS_RDATASET_FIXED */
	raw += length + 2;
#endif /* if DNS_RDATASET_FIXED */
	rdataset->private5 = raw;

	return (ISC_R_SUCCESS);
}

static void
rdataset_current(dns_rdataset_t *rdataset, dns_rdata_t *rdata) {
	unsigned char *raw = rdataset->private5;
	isc_region_t r;
	unsigned int length;
	unsigned int flags = 0;

	REQUIRE(raw != NULL);

	length = raw[0] * 256 + raw[1];
#if DNS_RDATASET_FIXED
	raw += 4;
#else  /* if DNS_RDATASET_FIXED */
	raw += 2;
#endif /* if DNS_RDATASET_FIXED */
	if (rdataset->type == dns_rdatatype_rrsig) {
		if ((*raw & DNS_RDATASLAB_OFFLINE) != 0) {
			flags |= DNS_RDATA_OFFLINE;
		}
		length--;
		raw++;
	}
	r.length = length;
	r.base = raw;
	dns_rdata_fromregion(rdata, rdataset->rdclass, rdataset->type, &r);
	rdata->flags |= flags;
}

static void
rdataset_clone(dns_rdataset_t *source, dns_rdataset_t *target) {
	dns_db_t *db = source->private1;
	dns_dbnode_t *node = source->private2;
	dns_dbnode_t *cloned_node = NULL;

	attachnode(db, node, &cloned_node);
	*target = *source;

	/*
	 * Reset iterator state.
	 */
	target->privateuint4 = 0;
	target->private5 = NULL;
}

static unsigned int
rdataset_count(dns_rdataset_t *rdataset) {
	unsigned char *raw = rdataset->private3;
	unsigned int count;

	count = raw[0] * 256 + raw[1];

	return (count);
}

static void
rdataset_settrust(dns_rdataset_t *rdataset, dns_trust_t trust) {
	rdatasetheader_t *header = rdataset->private3;

	header--;
	header->trust = rdataset->trust = trust;
}

/*
 * Rdataset Iterator Methods
 */

static void
rdatasetiter_destroy(dns_rdatasetiter_t **iteratorp) {
	isc_mem_t *mctx;
	union {
		dns_rdatasetiter_t *rdatasetiterator;
		ecdb_rdatasetiter_t *ecdbiterator;
	} u;

	REQUIRE(iteratorp != NULL);
	REQUIRE(DNS_RDATASETITER_VALID(*iteratorp));

	u.rdatasetiterator = *iteratorp;
	*iteratorp = NULL;

	mctx = u.ecdbiterator->common.db->mctx;
	u.ecdbiterator->common.magic = 0;

	dns_db_detachnode(u.ecdbiterator->common.db,
			  &u.ecdbiterator->common.node);
	isc_mem_put(mctx, u.ecdbiterator, sizeof(ecdb_rdatasetiter_t));
}

static isc_result_t
rdatasetiter_first(dns_rdatasetiter_t *iterator) {
	REQUIRE(DNS_RDATASETITER_VALID(iterator));

	ecdb_rdatasetiter_t *ecdbiterator = (ecdb_rdatasetiter_t *)iterator;
	dns_ecdbnode_t *ecdbnode = (dns_ecdbnode_t *)iterator->node;

	if (ISC_LIST_EMPTY(ecdbnode->rdatasets)) {
		return (ISC_R_NOMORE);
	}
	ecdbiterator->current = ISC_LIST_HEAD(ecdbnode->rdatasets);
	return (ISC_R_SUCCESS);
}

static isc_result_t
rdatasetiter_next(dns_rdatasetiter_t *iterator) {
	REQUIRE(DNS_RDATASETITER_VALID(iterator));

	ecdb_rdatasetiter_t *ecdbiterator = (ecdb_rdatasetiter_t *)iterator;

	ecdbiterator->current = ISC_LIST_NEXT(ecdbiterator->current, link);
	if (ecdbiterator->current == NULL) {
		return (ISC_R_NOMORE);
	} else {
		return (ISC_R_SUCCESS);
	}
}

static void
rdatasetiter_current(dns_rdatasetiter_t *iterator, dns_rdataset_t *rdataset) {
	ecdb_rdatasetiter_t *ecdbiterator = (ecdb_rdatasetiter_t *)iterator;
	dns_ecdb_t *ecdb;

	ecdb = (dns_ecdb_t *)iterator->db;
	REQUIRE(VALID_ECDB(ecdb));

	bind_rdataset(ecdb, iterator->node, ecdbiterator->current, rdataset);
}