Adding upstream version 1:9.16.44.upstream/1%9.16.44upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 750 insertions, 0 deletions

diff --git a/lib/dns/rdataset.c b/lib/dns/rdataset.c
new file mode 100644
index 0000000..221d7f8
--- /dev/null
+++ b/lib/dns/rdataset.c
@@ -0,0 +1,750 @@
+/*
+ * 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.
+ */
+
+/*! \file */
+
+#include <inttypes.h>
+#include <stdbool.h>
+#include <stdlib.h>
+
+#include <isc/buffer.h>
+#include <isc/mem.h>
+#include <isc/random.h>
+#include <isc/serial.h>
+#include <isc/util.h>
+
+#include <dns/compress.h>
+#include <dns/fixedname.h>
+#include <dns/name.h>
+#include <dns/ncache.h>
+#include <dns/rdata.h>
+#include <dns/rdataset.h>
+
+static const char *trustnames[] = {
+	"none",		  "pending-additional",
+	"pending-answer", "additional",
+	"glue",		  "answer",
+	"authauthority",  "authanswer",
+	"secure",	  "local" /* aka ultimate */
+};
+
+const char *
+dns_trust_totext(dns_trust_t trust) {
+	if (trust >= sizeof(trustnames) / sizeof(*trustnames)) {
+		return ("bad");
+	}
+	return (trustnames[trust]);
+}
+
+#define DNS_RDATASET_COUNT_UNDEFINED UINT32_MAX
+
+void
+dns_rdataset_init(dns_rdataset_t *rdataset) {
+	/*
+	 * Make 'rdataset' a valid, disassociated rdataset.
+	 */
+
+	REQUIRE(rdataset != NULL);
+
+	rdataset->magic = DNS_RDATASET_MAGIC;
+	rdataset->methods = NULL;
+	ISC_LINK_INIT(rdataset, link);
+	rdataset->rdclass = 0;
+	rdataset->type = 0;
+	rdataset->ttl = 0;
+	rdataset->trust = 0;
+	rdataset->covers = 0;
+	rdataset->attributes = 0;
+	rdataset->count = DNS_RDATASET_COUNT_UNDEFINED;
+	rdataset->private1 = NULL;
+	rdataset->private2 = NULL;
+	rdataset->private3 = NULL;
+	rdataset->privateuint4 = 0;
+	rdataset->private5 = NULL;
+	rdataset->private6 = NULL;
+	rdataset->private7 = NULL;
+	rdataset->resign = 0;
+}
+
+void
+dns_rdataset_invalidate(dns_rdataset_t *rdataset) {
+	/*
+	 * Invalidate 'rdataset'.
+	 */
+
+	REQUIRE(DNS_RDATASET_VALID(rdataset));
+	REQUIRE(rdataset->methods == NULL);
+
+	rdataset->magic = 0;
+	ISC_LINK_INIT(rdataset, link);
+	rdataset->rdclass = 0;
+	rdataset->type = 0;
+	rdataset->ttl = 0;
+	rdataset->trust = 0;
+	rdataset->covers = 0;
+	rdataset->attributes = 0;
+	rdataset->count = DNS_RDATASET_COUNT_UNDEFINED;
+	rdataset->private1 = NULL;
+	rdataset->private2 = NULL;
+	rdataset->private3 = NULL;
+	rdataset->privateuint4 = 0;
+	rdataset->private5 = NULL;
+}
+
+void
+dns_rdataset_disassociate(dns_rdataset_t *rdataset) {
+	/*
+	 * Disassociate 'rdataset' from its rdata, allowing it to be reused.
+	 */
+
+	REQUIRE(DNS_RDATASET_VALID(rdataset));
+	REQUIRE(rdataset->methods != NULL);
+
+	(rdataset->methods->disassociate)(rdataset);
+	rdataset->methods = NULL;
+	ISC_LINK_INIT(rdataset, link);
+	rdataset->rdclass = 0;
+	rdataset->type = 0;
+	rdataset->ttl = 0;
+	rdataset->trust = 0;
+	rdataset->covers = 0;
+	rdataset->attributes = 0;
+	rdataset->count = DNS_RDATASET_COUNT_UNDEFINED;
+	rdataset->private1 = NULL;
+	rdataset->private2 = NULL;
+	rdataset->private3 = NULL;
+	rdataset->privateuint4 = 0;
+	rdataset->private5 = NULL;
+	rdataset->private6 = NULL;
+}
+
+bool
+dns_rdataset_isassociated(dns_rdataset_t *rdataset) {
+	/*
+	 * Is 'rdataset' associated?
+	 */
+
+	REQUIRE(DNS_RDATASET_VALID(rdataset));
+
+	if (rdataset->methods != NULL) {
+		return (true);
+	}
+
+	return (false);
+}
+
+static void
+question_disassociate(dns_rdataset_t *rdataset) {
+	UNUSED(rdataset);
+}
+
+static isc_result_t
+question_cursor(dns_rdataset_t *rdataset) {
+	UNUSED(rdataset);
+
+	return (ISC_R_NOMORE);
+}
+
+static void
+question_current(dns_rdataset_t *rdataset, dns_rdata_t *rdata) {
+	/*
+	 * This routine should never be called.
+	 */
+	UNUSED(rdataset);
+	UNUSED(rdata);
+
+	REQUIRE(0);
+}
+
+static void
+question_clone(dns_rdataset_t *source, dns_rdataset_t *target) {
+	*target = *source;
+}
+
+static unsigned int
+question_count(dns_rdataset_t *rdataset) {
+	/*
+	 * This routine should never be called.
+	 */
+	UNUSED(rdataset);
+	REQUIRE(0);
+
+	return (0);
+}
+
+static dns_rdatasetmethods_t question_methods = {
+	question_disassociate,
+	question_cursor,
+	question_cursor,
+	question_current,
+	question_clone,
+	question_count,
+	NULL, /* addnoqname */
+	NULL, /* getnoqname */
+	NULL, /* addclosest */
+	NULL, /* getclosest */
+	NULL, /* settrust */
+	NULL, /* expire */
+	NULL, /* clearprefetch */
+	NULL, /* setownercase */
+	NULL, /* getownercase */
+	NULL  /* addglue */
+};
+
+void
+dns_rdataset_makequestion(dns_rdataset_t *rdataset, dns_rdataclass_t rdclass,
+			  dns_rdatatype_t type) {
+	/*
+	 * Make 'rdataset' a valid, associated, question rdataset, with a
+	 * question class of 'rdclass' and type 'type'.
+	 */
+
+	REQUIRE(DNS_RDATASET_VALID(rdataset));
+	REQUIRE(rdataset->methods == NULL);
+
+	rdataset->methods = &question_methods;
+	rdataset->rdclass = rdclass;
+	rdataset->type = type;
+	rdataset->attributes |= DNS_RDATASETATTR_QUESTION;
+}
+
+unsigned int
+dns_rdataset_count(dns_rdataset_t *rdataset) {
+	/*
+	 * Return the number of records in 'rdataset'.
+	 */
+
+	REQUIRE(DNS_RDATASET_VALID(rdataset));
+	REQUIRE(rdataset->methods != NULL);
+
+	return ((rdataset->methods->count)(rdataset));
+}
+
+void
+dns_rdataset_clone(dns_rdataset_t *source, dns_rdataset_t *target) {
+	/*
+	 * Make 'target' refer to the same rdataset as 'source'.
+	 */
+
+	REQUIRE(DNS_RDATASET_VALID(source));
+	REQUIRE(source->methods != NULL);
+	REQUIRE(DNS_RDATASET_VALID(target));
+	REQUIRE(target->methods == NULL);
+
+	(source->methods->clone)(source, target);
+}
+
+isc_result_t
+dns_rdataset_first(dns_rdataset_t *rdataset) {
+	/*
+	 * Move the rdata cursor to the first rdata in the rdataset (if any).
+	 */
+
+	REQUIRE(DNS_RDATASET_VALID(rdataset));
+	REQUIRE(rdataset->methods != NULL);
+
+	return ((rdataset->methods->first)(rdataset));
+}
+
+isc_result_t
+dns_rdataset_next(dns_rdataset_t *rdataset) {
+	/*
+	 * Move the rdata cursor to the next rdata in the rdataset (if any).
+	 */
+
+	REQUIRE(DNS_RDATASET_VALID(rdataset));
+	REQUIRE(rdataset->methods != NULL);
+
+	return ((rdataset->methods->next)(rdataset));
+}
+
+void
+dns_rdataset_current(dns_rdataset_t *rdataset, dns_rdata_t *rdata) {
+	/*
+	 * Make 'rdata' refer to the current rdata.
+	 */
+
+	REQUIRE(DNS_RDATASET_VALID(rdataset));
+	REQUIRE(rdataset->methods != NULL);
+
+	(rdataset->methods->current)(rdataset, rdata);
+}
+
+#define MAX_SHUFFLE    32
+#define WANT_FIXED(r)  (((r)->attributes & DNS_RDATASETATTR_FIXEDORDER) != 0)
+#define WANT_RANDOM(r) (((r)->attributes & DNS_RDATASETATTR_RANDOMIZE) != 0)
+#define WANT_CYCLIC(r) (((r)->attributes & DNS_RDATASETATTR_CYCLIC) != 0)
+
+struct towire_sort {
+	int key;
+	dns_rdata_t *rdata;
+};
+
+static int
+towire_compare(const void *av, const void *bv) {
+	const struct towire_sort *a = (const struct towire_sort *)av;
+	const struct towire_sort *b = (const struct towire_sort *)bv;
+	return (a->key - b->key);
+}
+
+static void
+swap_rdata(dns_rdata_t *in, unsigned int a, unsigned int b) {
+	dns_rdata_t rdata = in[a];
+	in[a] = in[b];
+	in[b] = rdata;
+}
+
+static isc_result_t
+towiresorted(dns_rdataset_t *rdataset, const dns_name_t *owner_name,
+	     dns_compress_t *cctx, isc_buffer_t *target,
+	     dns_rdatasetorderfunc_t order, const void *order_arg, bool partial,
+	     unsigned int options, unsigned int *countp, void **state) {
+	isc_region_t r;
+	isc_result_t result;
+	unsigned int i, count = 0, added;
+	isc_buffer_t savedbuffer, rdlen, rrbuffer;
+	unsigned int headlen;
+	bool question = false;
+	bool shuffle = false, sort = false;
+	bool want_random, want_cyclic;
+	dns_rdata_t in_fixed[MAX_SHUFFLE];
+	dns_rdata_t *in = in_fixed;
+	struct towire_sort out_fixed[MAX_SHUFFLE];
+	struct towire_sort *out = out_fixed;
+	dns_fixedname_t fixed;
+	dns_name_t *name;
+	uint16_t offset;
+
+	UNUSED(state);
+
+	/*
+	 * Convert 'rdataset' to wire format, compressing names as specified
+	 * in cctx, and storing the result in 'target'.
+	 */
+
+	REQUIRE(DNS_RDATASET_VALID(rdataset));
+	REQUIRE(rdataset->methods != NULL);
+	REQUIRE(countp != NULL);
+	REQUIRE(cctx != NULL && cctx->mctx != NULL);
+
+	want_random = WANT_RANDOM(rdataset);
+	want_cyclic = WANT_CYCLIC(rdataset);
+
+	if ((rdataset->attributes & DNS_RDATASETATTR_QUESTION) != 0) {
+		question = true;
+		count = 1;
+		result = dns_rdataset_first(rdataset);
+		INSIST(result == ISC_R_NOMORE);
+	} else if ((rdataset->attributes & DNS_RDATASETATTR_NEGATIVE) != 0) {
+		/*
+		 * This is a negative caching rdataset.
+		 */
+		unsigned int ncache_opts = 0;
+		if ((options & DNS_RDATASETTOWIRE_OMITDNSSEC) != 0) {
+			ncache_opts |= DNS_NCACHETOWIRE_OMITDNSSEC;
+		}
+		return (dns_ncache_towire(rdataset, cctx, target, ncache_opts,
+					  countp));
+	} else {
+		count = (rdataset->methods->count)(rdataset);
+		result = dns_rdataset_first(rdataset);
+		if (result == ISC_R_NOMORE) {
+			return (ISC_R_SUCCESS);
+		}
+		if (result != ISC_R_SUCCESS) {
+			return (result);
+		}
+	}
+
+	/*
+	 * Do we want to sort and/or shuffle this answer?
+	 */
+	if (!question && count > 1 && rdataset->type != dns_rdatatype_rrsig) {
+		if (order != NULL) {
+			sort = true;
+		}
+		if (want_random || want_cyclic) {
+			shuffle = true;
+		}
+	}
+
+	if ((shuffle || sort)) {
+		if (count > MAX_SHUFFLE) {
+			in = isc_mem_get(cctx->mctx, count * sizeof(*in));
+			out = isc_mem_get(cctx->mctx, count * sizeof(*out));
+			if (in == NULL || out == NULL) {
+				shuffle = sort = false;
+			}
+		}
+	}
+
+	if ((shuffle || sort)) {
+		uint32_t seed = 0;
+		unsigned int j = 0;
+
+		/*
+		 * First we get handles to all of the rdata.
+		 */
+		i = 0;
+		do {
+			INSIST(i < count);
+			dns_rdata_init(&in[i]);
+			dns_rdataset_current(rdataset, &in[i]);
+			i++;
+			result = dns_rdataset_next(rdataset);
+		} while (result == ISC_R_SUCCESS);
+		if (result != ISC_R_NOMORE) {
+			goto cleanup;
+		}
+		INSIST(i == count);
+
+		if (ISC_LIKELY(want_random)) {
+			seed = isc_random32();
+		}
+
+		if (ISC_UNLIKELY(want_cyclic) &&
+		    (rdataset->count != DNS_RDATASET_COUNT_UNDEFINED))
+		{
+			j = rdataset->count % count;
+		}
+
+		for (i = 0; i < count; i++) {
+			if (ISC_LIKELY(want_random)) {
+				swap_rdata(in, j, j + seed % (count - j));
+			}
+
+			out[i].key = (sort) ? (*order)(&in[j], order_arg) : 0;
+			out[i].rdata = &in[j];
+			if (++j == count) {
+				j = 0;
+			}
+		}
+		/*
+		 * Sortlist order.
+		 */
+		if (sort) {
+			qsort(out, count, sizeof(out[0]), towire_compare);
+		}
+	}
+
+	savedbuffer = *target;
+	i = 0;
+	added = 0;
+
+	name = dns_fixedname_initname(&fixed);
+	dns_name_copynf(owner_name, name);
+	dns_rdataset_getownercase(rdataset, name);
+	offset = 0xffff;
+
+	name->attributes |= owner_name->attributes & DNS_NAMEATTR_NOCOMPRESS;
+
+	do {
+		/*
+		 * Copy out the name, type, class, ttl.
+		 */
+
+		rrbuffer = *target;
+		dns_compress_setmethods(cctx, DNS_COMPRESS_GLOBAL14);
+		result = dns_name_towire2(name, cctx, target, &offset);
+		if (result != ISC_R_SUCCESS) {
+			goto rollback;
+		}
+		headlen = sizeof(dns_rdataclass_t) + sizeof(dns_rdatatype_t);
+		if (!question) {
+			headlen += sizeof(dns_ttl_t) + 2;
+		} /* XXX 2 for rdata len
+		   */
+		isc_buffer_availableregion(target, &r);
+		if (r.length < headlen) {
+			result = ISC_R_NOSPACE;
+			goto rollback;
+		}
+		isc_buffer_putuint16(target, rdataset->type);
+		isc_buffer_putuint16(target, rdataset->rdclass);
+		if (!question) {
+			dns_rdata_t rdata = DNS_RDATA_INIT;
+
+			isc_buffer_putuint32(target, rdataset->ttl);
+
+			/*
+			 * Save space for rdlen.
+			 */
+			rdlen = *target;
+			isc_buffer_add(target, 2);
+
+			/*
+			 * Copy out the rdata
+			 */
+			if (shuffle || sort) {
+				rdata = *(out[i].rdata);
+			} else {
+				dns_rdata_reset(&rdata);
+				dns_rdataset_current(rdataset, &rdata);
+			}
+			result = dns_rdata_towire(&rdata, cctx, target);
+			if (result != ISC_R_SUCCESS) {
+				goto rollback;
+			}
+			INSIST((target->used >= rdlen.used + 2) &&
+			       (target->used - rdlen.used - 2 < 65536));
+			isc_buffer_putuint16(
+				&rdlen,
+				(uint16_t)(target->used - rdlen.used - 2));
+			added++;
+		}
+
+		if (shuffle || sort) {
+			i++;
+			if (i == count) {
+				result = ISC_R_NOMORE;
+			} else {
+				result = ISC_R_SUCCESS;
+			}
+		} else {
+			result = dns_rdataset_next(rdataset);
+		}
+	} while (result == ISC_R_SUCCESS);
+
+	if (result != ISC_R_NOMORE) {
+		goto rollback;
+	}
+
+	*countp += count;
+
+	result = ISC_R_SUCCESS;
+	goto cleanup;
+
+rollback:
+	if (partial && result == ISC_R_NOSPACE) {
+		INSIST(rrbuffer.used < 65536);
+		dns_compress_rollback(cctx, (uint16_t)rrbuffer.used);
+		*countp += added;
+		*target = rrbuffer;
+		goto cleanup;
+	}
+	INSIST(savedbuffer.used < 65536);
+	dns_compress_rollback(cctx, (uint16_t)savedbuffer.used);
+	*countp = 0;
+	*target = savedbuffer;
+
+cleanup:
+	if (out != NULL && out != out_fixed) {
+		isc_mem_put(cctx->mctx, out, count * sizeof(*out));
+	}
+	if (in != NULL && in != in_fixed) {
+		isc_mem_put(cctx->mctx, in, count * sizeof(*in));
+	}
+	return (result);
+}
+
+isc_result_t
+dns_rdataset_towiresorted(dns_rdataset_t *rdataset,
+			  const dns_name_t *owner_name, dns_compress_t *cctx,
+			  isc_buffer_t *target, dns_rdatasetorderfunc_t order,
+			  const void *order_arg, unsigned int options,
+			  unsigned int *countp) {
+	return (towiresorted(rdataset, owner_name, cctx, target, order,
+			     order_arg, false, options, countp, NULL));
+}
+
+isc_result_t
+dns_rdataset_towirepartial(dns_rdataset_t *rdataset,
+			   const dns_name_t *owner_name, dns_compress_t *cctx,
+			   isc_buffer_t *target, dns_rdatasetorderfunc_t order,
+			   const void *order_arg, unsigned int options,
+			   unsigned int *countp, void **state) {
+	REQUIRE(state == NULL); /* XXX remove when implemented */
+	return (towiresorted(rdataset, owner_name, cctx, target, order,
+			     order_arg, true, options, countp, state));
+}
+
+isc_result_t
+dns_rdataset_towire(dns_rdataset_t *rdataset, const dns_name_t *owner_name,
+		    dns_compress_t *cctx, isc_buffer_t *target,
+		    unsigned int options, unsigned int *countp) {
+	return (towiresorted(rdataset, owner_name, cctx, target, NULL, NULL,
+			     false, options, countp, NULL));
+}
+
+isc_result_t
+dns_rdataset_additionaldata(dns_rdataset_t *rdataset,
+			    dns_additionaldatafunc_t add, void *arg) {
+	dns_rdata_t rdata = DNS_RDATA_INIT;
+	isc_result_t result;
+
+	/*
+	 * For each rdata in rdataset, call 'add' for each name and type in the
+	 * rdata which is subject to additional section processing.
+	 */
+
+	REQUIRE(DNS_RDATASET_VALID(rdataset));
+	REQUIRE((rdataset->attributes & DNS_RDATASETATTR_QUESTION) == 0);
+
+	result = dns_rdataset_first(rdataset);
+	if (result != ISC_R_SUCCESS) {
+		return (result);
+	}
+
+	do {
+		dns_rdataset_current(rdataset, &rdata);
+		result = dns_rdata_additionaldata(&rdata, add, arg);
+		if (result == ISC_R_SUCCESS) {
+			result = dns_rdataset_next(rdataset);
+		}
+		dns_rdata_reset(&rdata);
+	} while (result == ISC_R_SUCCESS);
+
+	if (result != ISC_R_NOMORE) {
+		return (result);
+	}
+
+	return (ISC_R_SUCCESS);
+}
+
+isc_result_t
+dns_rdataset_addnoqname(dns_rdataset_t *rdataset, dns_name_t *name) {
+	REQUIRE(DNS_RDATASET_VALID(rdataset));
+	REQUIRE(rdataset->methods != NULL);
+	if (rdataset->methods->addnoqname == NULL) {
+		return (ISC_R_NOTIMPLEMENTED);
+	}
+	return ((rdataset->methods->addnoqname)(rdataset, name));
+}
+
+isc_result_t
+dns_rdataset_getnoqname(dns_rdataset_t *rdataset, dns_name_t *name,
+			dns_rdataset_t *neg, dns_rdataset_t *negsig) {
+	REQUIRE(DNS_RDATASET_VALID(rdataset));
+	REQUIRE(rdataset->methods != NULL);
+
+	if (rdataset->methods->getnoqname == NULL) {
+		return (ISC_R_NOTIMPLEMENTED);
+	}
+	return ((rdataset->methods->getnoqname)(rdataset, name, neg, negsig));
+}
+
+isc_result_t
+dns_rdataset_addclosest(dns_rdataset_t *rdataset, const dns_name_t *name) {
+	REQUIRE(DNS_RDATASET_VALID(rdataset));
+	REQUIRE(rdataset->methods != NULL);
+	if (rdataset->methods->addclosest == NULL) {
+		return (ISC_R_NOTIMPLEMENTED);
+	}
+	return ((rdataset->methods->addclosest)(rdataset, name));
+}
+
+isc_result_t
+dns_rdataset_getclosest(dns_rdataset_t *rdataset, dns_name_t *name,
+			dns_rdataset_t *neg, dns_rdataset_t *negsig) {
+	REQUIRE(DNS_RDATASET_VALID(rdataset));
+	REQUIRE(rdataset->methods != NULL);
+
+	if (rdataset->methods->getclosest == NULL) {
+		return (ISC_R_NOTIMPLEMENTED);
+	}
+	return ((rdataset->methods->getclosest)(rdataset, name, neg, negsig));
+}
+
+void
+dns_rdataset_settrust(dns_rdataset_t *rdataset, dns_trust_t trust) {
+	REQUIRE(DNS_RDATASET_VALID(rdataset));
+	REQUIRE(rdataset->methods != NULL);
+
+	if (rdataset->methods->settrust != NULL) {
+		(rdataset->methods->settrust)(rdataset, trust);
+	} else {
+		rdataset->trust = trust;
+	}
+}
+
+void
+dns_rdataset_expire(dns_rdataset_t *rdataset) {
+	REQUIRE(DNS_RDATASET_VALID(rdataset));
+	REQUIRE(rdataset->methods != NULL);
+
+	if (rdataset->methods->expire != NULL) {
+		(rdataset->methods->expire)(rdataset);
+	}
+}
+
+void
+dns_rdataset_clearprefetch(dns_rdataset_t *rdataset) {
+	REQUIRE(DNS_RDATASET_VALID(rdataset));
+	REQUIRE(rdataset->methods != NULL);
+
+	if (rdataset->methods->clearprefetch != NULL) {
+		(rdataset->methods->clearprefetch)(rdataset);
+	}
+}
+
+void
+dns_rdataset_setownercase(dns_rdataset_t *rdataset, const dns_name_t *name) {
+	REQUIRE(DNS_RDATASET_VALID(rdataset));
+	REQUIRE(rdataset->methods != NULL);
+
+	if (rdataset->methods->setownercase != NULL) {
+		(rdataset->methods->setownercase)(rdataset, name);
+	}
+}
+
+void
+dns_rdataset_getownercase(const dns_rdataset_t *rdataset, dns_name_t *name) {
+	REQUIRE(DNS_RDATASET_VALID(rdataset));
+	REQUIRE(rdataset->methods != NULL);
+
+	if (rdataset->methods->getownercase != NULL) {
+		(rdataset->methods->getownercase)(rdataset, name);
+	}
+}
+
+void
+dns_rdataset_trimttl(dns_rdataset_t *rdataset, dns_rdataset_t *sigrdataset,
+		     dns_rdata_rrsig_t *rrsig, isc_stdtime_t now,
+		     bool acceptexpired) {
+	uint32_t ttl = 0;
+
+	REQUIRE(DNS_RDATASET_VALID(rdataset));
+	REQUIRE(DNS_RDATASET_VALID(sigrdataset));
+	REQUIRE(rrsig != NULL);
+
+	/*
+	 * If we accept expired RRsets keep them for no more than 120 seconds.
+	 */
+	if (acceptexpired &&
+	    (isc_serial_le(rrsig->timeexpire, ((now + 120) & 0xffffffff)) ||
+	     isc_serial_le(rrsig->timeexpire, now)))
+	{
+		ttl = 120;
+	} else if (isc_serial_ge(rrsig->timeexpire, now)) {
+		ttl = rrsig->timeexpire - now;
+	}
+
+	ttl = ISC_MIN(ISC_MIN(rdataset->ttl, sigrdataset->ttl),
+		      ISC_MIN(rrsig->originalttl, ttl));
+	rdataset->ttl = ttl;
+	sigrdataset->ttl = ttl;
+}
+
+isc_result_t
+dns_rdataset_addglue(dns_rdataset_t *rdataset, dns_dbversion_t *version,
+		     dns_message_t *msg) {
+	REQUIRE(DNS_RDATASET_VALID(rdataset));
+	REQUIRE(rdataset->methods != NULL);
+	REQUIRE(rdataset->type == dns_rdatatype_ns);
+
+	if (rdataset->methods->addglue == NULL) {
+		return (ISC_R_NOTIMPLEMENTED);
+	}
+
+	return ((rdataset->methods->addglue)(rdataset, version, msg));
+}