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

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

1 files changed, 1367 insertions, 0 deletions

diff --git a/lib/dns/rrl.c b/lib/dns/rrl.c
new file mode 100644
index 0000000..a8c2525
--- /dev/null
+++ b/lib/dns/rrl.c
@@ -0,0 +1,1367 @@
+/*
+ * 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 */
+
+/*
+ * Rate limit DNS responses.
+ */
+
+/* #define ISC_LIST_CHECKINIT */
+
+#include <inttypes.h>
+#include <stdbool.h>
+
+#include <isc/mem.h>
+#include <isc/net.h>
+#include <isc/netaddr.h>
+#include <isc/print.h>
+#include <isc/util.h>
+
+#include <dns/log.h>
+#include <dns/name.h>
+#include <dns/rcode.h>
+#include <dns/rdataclass.h>
+#include <dns/rdatatype.h>
+#include <dns/result.h>
+#include <dns/rrl.h>
+#include <dns/view.h>
+#include <dns/zone.h>
+
+static void
+log_end(dns_rrl_t *rrl, dns_rrl_entry_t *e, bool early, char *log_buf,
+	unsigned int log_buf_len);
+
+/*
+ * Get a modulus for a hash function that is tolerably likely to be
+ * relatively prime to most inputs.  Of course, we get a prime for for initial
+ * values not larger than the square of the last prime.  We often get a prime
+ * after that.
+ * This works well in practice for hash tables up to at least 100
+ * times the square of the last prime and better than a multiplicative hash.
+ */
+static int
+hash_divisor(unsigned int initial) {
+	static uint16_t primes[] = {
+		3,
+		5,
+		7,
+		11,
+		13,
+		17,
+		19,
+		23,
+		29,
+		31,
+		37,
+		41,
+		43,
+		47,
+		53,
+		59,
+		61,
+		67,
+		71,
+		73,
+		79,
+		83,
+		89,
+		97,
+#if 0
+		101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157,
+		163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227,
+		229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 283,
+		293, 307, 311, 313, 317, 331, 337, 347, 349, 353, 359, 367,
+		373, 379, 383, 389, 397, 401, 409, 419, 421, 431, 433, 439,
+		443, 449, 457, 461, 463, 467, 479, 487, 491, 499, 503, 509,
+		521, 523, 541, 547, 557, 563, 569, 571, 577, 587, 593, 599,
+		601, 607, 613, 617, 619, 631, 641, 643, 647, 653, 659, 661,
+		673, 677, 683, 691, 701, 709, 719, 727, 733, 739, 743, 751,
+		757, 761, 769, 773, 787, 797, 809, 811, 821, 823, 827, 829,
+		839, 853, 857, 859, 863, 877, 881, 883, 887, 907, 911, 919,
+		929, 937, 941, 947, 953, 967, 971, 977, 983, 991, 997, 1009,
+#endif /* if 0 */
+	};
+	int divisions, tries;
+	unsigned int result;
+	uint16_t *pp, p;
+
+	result = initial;
+
+	if (primes[sizeof(primes) / sizeof(primes[0]) - 1] >= result) {
+		pp = primes;
+		while (*pp < result) {
+			++pp;
+		}
+		return (*pp);
+	}
+
+	if ((result & 1) == 0) {
+		++result;
+	}
+
+	divisions = 0;
+	tries = 1;
+	pp = primes;
+	do {
+		p = *pp++;
+		++divisions;
+		if ((result % p) == 0) {
+			++tries;
+			result += 2;
+			pp = primes;
+		}
+	} while (pp < &primes[sizeof(primes) / sizeof(primes[0])]);
+
+	if (isc_log_wouldlog(dns_lctx, DNS_RRL_LOG_DEBUG3)) {
+		isc_log_write(dns_lctx, DNS_LOGCATEGORY_RRL,
+			      DNS_LOGMODULE_REQUEST, DNS_RRL_LOG_DEBUG3,
+			      "%d hash_divisor() divisions in %d tries"
+			      " to get %d from %d",
+			      divisions, tries, result, initial);
+	}
+
+	return (result);
+}
+
+/*
+ * Convert a timestamp to a number of seconds in the past.
+ */
+static int
+delta_rrl_time(isc_stdtime_t ts, isc_stdtime_t now) {
+	int delta;
+
+	delta = now - ts;
+	if (delta >= 0) {
+		return (delta);
+	}
+
+	/*
+	 * The timestamp is in the future.  That future might result from
+	 * re-ordered requests, because we use timestamps on requests
+	 * instead of consulting a clock.  Timestamps in the distant future are
+	 * assumed to result from clock changes.  When the clock changes to
+	 * the past, make existing timestamps appear to be in the past.
+	 */
+	if (delta < -DNS_RRL_MAX_TIME_TRAVEL) {
+		return (DNS_RRL_FOREVER);
+	}
+	return (0);
+}
+
+static int
+get_age(const dns_rrl_t *rrl, const dns_rrl_entry_t *e, isc_stdtime_t now) {
+	if (!e->ts_valid) {
+		return (DNS_RRL_FOREVER);
+	}
+	return (delta_rrl_time(e->ts + rrl->ts_bases[e->ts_gen], now));
+}
+
+static void
+set_age(dns_rrl_t *rrl, dns_rrl_entry_t *e, isc_stdtime_t now) {
+	dns_rrl_entry_t *e_old;
+	unsigned int ts_gen;
+	int i, ts;
+
+	ts_gen = rrl->ts_gen;
+	ts = now - rrl->ts_bases[ts_gen];
+	if (ts < 0) {
+		if (ts < -DNS_RRL_MAX_TIME_TRAVEL) {
+			ts = DNS_RRL_FOREVER;
+		} else {
+			ts = 0;
+		}
+	}
+
+	/*
+	 * Make a new timestamp base if the current base is too old.
+	 * All entries older than DNS_RRL_MAX_WINDOW seconds are ancient,
+	 * useless history.  Their timestamps can be treated as if they are
+	 * all the same.
+	 * We only do arithmetic on more recent timestamps, so bases for
+	 * older timestamps can be recycled provided the old timestamps are
+	 * marked as ancient history.
+	 * This loop is almost always very short because most entries are
+	 * recycled after one second and any entries that need to be marked
+	 * are older than (DNS_RRL_TS_BASES)*DNS_RRL_MAX_TS seconds.
+	 */
+	if (ts >= DNS_RRL_MAX_TS) {
+		ts_gen = (ts_gen + 1) % DNS_RRL_TS_BASES;
+		for (e_old = ISC_LIST_TAIL(rrl->lru), i = 0;
+		     e_old != NULL && (e_old->ts_gen == ts_gen ||
+				       !ISC_LINK_LINKED(e_old, hlink));
+		     e_old = ISC_LIST_PREV(e_old, lru), ++i)
+		{
+			e_old->ts_valid = false;
+		}
+		if (i != 0) {
+			isc_log_write(
+				dns_lctx, DNS_LOGCATEGORY_RRL,
+				DNS_LOGMODULE_REQUEST, DNS_RRL_LOG_DEBUG1,
+				"rrl new time base scanned %d entries"
+				" at %d for %d %d %d %d",
+				i, now, rrl->ts_bases[ts_gen],
+				rrl->ts_bases[(ts_gen + 1) % DNS_RRL_TS_BASES],
+				rrl->ts_bases[(ts_gen + 2) % DNS_RRL_TS_BASES],
+				rrl->ts_bases[(ts_gen + 3) % DNS_RRL_TS_BASES]);
+		}
+		rrl->ts_gen = ts_gen;
+		rrl->ts_bases[ts_gen] = now;
+		ts = 0;
+	}
+
+	e->ts_gen = ts_gen;
+	e->ts = ts;
+	e->ts_valid = true;
+}
+
+static isc_result_t
+expand_entries(dns_rrl_t *rrl, int newsize) {
+	unsigned int bsize;
+	dns_rrl_block_t *b;
+	dns_rrl_entry_t *e;
+	double rate;
+	int i;
+
+	if (rrl->num_entries + newsize >= rrl->max_entries &&
+	    rrl->max_entries != 0)
+	{
+		newsize = rrl->max_entries - rrl->num_entries;
+		if (newsize <= 0) {
+			return (ISC_R_SUCCESS);
+		}
+	}
+
+	/*
+	 * Log expansions so that the user can tune max-table-size
+	 * and min-table-size.
+	 */
+	if (isc_log_wouldlog(dns_lctx, DNS_RRL_LOG_DROP) && rrl->hash != NULL) {
+		rate = rrl->probes;
+		if (rrl->searches != 0) {
+			rate /= rrl->searches;
+		}
+		isc_log_write(dns_lctx, DNS_LOGCATEGORY_RRL,
+			      DNS_LOGMODULE_REQUEST, DNS_RRL_LOG_DROP,
+			      "increase from %d to %d RRL entries with"
+			      " %d bins; average search length %.1f",
+			      rrl->num_entries, rrl->num_entries + newsize,
+			      rrl->hash->length, rate);
+	}
+
+	bsize = sizeof(dns_rrl_block_t) +
+		(newsize - 1) * sizeof(dns_rrl_entry_t);
+	b = isc_mem_get(rrl->mctx, bsize);
+	memset(b, 0, bsize);
+	b->size = bsize;
+
+	e = b->entries;
+	for (i = 0; i < newsize; ++i, ++e) {
+		ISC_LINK_INIT(e, hlink);
+		ISC_LIST_INITANDAPPEND(rrl->lru, e, lru);
+	}
+	rrl->num_entries += newsize;
+	ISC_LIST_INITANDAPPEND(rrl->blocks, b, link);
+
+	return (ISC_R_SUCCESS);
+}
+
+static dns_rrl_bin_t *
+get_bin(dns_rrl_hash_t *hash, unsigned int hval) {
+	INSIST(hash != NULL);
+	return (&hash->bins[hval % hash->length]);
+}
+
+static void
+free_old_hash(dns_rrl_t *rrl) {
+	dns_rrl_hash_t *old_hash;
+	dns_rrl_bin_t *old_bin;
+	dns_rrl_entry_t *e, *e_next;
+
+	old_hash = rrl->old_hash;
+	for (old_bin = &old_hash->bins[0];
+	     old_bin < &old_hash->bins[old_hash->length]; ++old_bin)
+	{
+		for (e = ISC_LIST_HEAD(*old_bin); e != NULL; e = e_next) {
+			e_next = ISC_LIST_NEXT(e, hlink);
+			ISC_LINK_INIT(e, hlink);
+		}
+	}
+
+	isc_mem_put(rrl->mctx, old_hash,
+		    sizeof(*old_hash) +
+			    (old_hash->length - 1) * sizeof(old_hash->bins[0]));
+	rrl->old_hash = NULL;
+}
+
+static isc_result_t
+expand_rrl_hash(dns_rrl_t *rrl, isc_stdtime_t now) {
+	dns_rrl_hash_t *hash;
+	int old_bins, new_bins, hsize;
+	double rate;
+
+	if (rrl->old_hash != NULL) {
+		free_old_hash(rrl);
+	}
+
+	/*
+	 * Most searches fail and so go to the end of the chain.
+	 * Use a small hash table load factor.
+	 */
+	old_bins = (rrl->hash == NULL) ? 0 : rrl->hash->length;
+	new_bins = old_bins / 8 + old_bins;
+	if (new_bins < rrl->num_entries) {
+		new_bins = rrl->num_entries;
+	}
+	new_bins = hash_divisor(new_bins);
+
+	hsize = sizeof(dns_rrl_hash_t) + (new_bins - 1) * sizeof(hash->bins[0]);
+	hash = isc_mem_get(rrl->mctx, hsize);
+	memset(hash, 0, hsize);
+	hash->length = new_bins;
+	rrl->hash_gen ^= 1;
+	hash->gen = rrl->hash_gen;
+
+	if (isc_log_wouldlog(dns_lctx, DNS_RRL_LOG_DROP) && old_bins != 0) {
+		rate = rrl->probes;
+		if (rrl->searches != 0) {
+			rate /= rrl->searches;
+		}
+		isc_log_write(dns_lctx, DNS_LOGCATEGORY_RRL,
+			      DNS_LOGMODULE_REQUEST, DNS_RRL_LOG_DROP,
+			      "increase from %d to %d RRL bins for"
+			      " %d entries; average search length %.1f",
+			      old_bins, new_bins, rrl->num_entries, rate);
+	}
+
+	rrl->old_hash = rrl->hash;
+	if (rrl->old_hash != NULL) {
+		rrl->old_hash->check_time = now;
+	}
+	rrl->hash = hash;
+
+	return (ISC_R_SUCCESS);
+}
+
+static void
+ref_entry(dns_rrl_t *rrl, dns_rrl_entry_t *e, int probes, isc_stdtime_t now) {
+	/*
+	 * Make the entry most recently used.
+	 */
+	if (ISC_LIST_HEAD(rrl->lru) != e) {
+		if (e == rrl->last_logged) {
+			rrl->last_logged = ISC_LIST_PREV(e, lru);
+		}
+		ISC_LIST_UNLINK(rrl->lru, e, lru);
+		ISC_LIST_PREPEND(rrl->lru, e, lru);
+	}
+
+	/*
+	 * Expand the hash table if it is time and necessary.
+	 * This will leave the newly referenced entry in a chain in the
+	 * old hash table.  It will migrate to the new hash table the next
+	 * time it is used or be cut loose when the old hash table is destroyed.
+	 */
+	rrl->probes += probes;
+	++rrl->searches;
+	if (rrl->searches > 100 &&
+	    delta_rrl_time(rrl->hash->check_time, now) > 1)
+	{
+		if (rrl->probes / rrl->searches > 2) {
+			expand_rrl_hash(rrl, now);
+		}
+		rrl->hash->check_time = now;
+		rrl->probes = 0;
+		rrl->searches = 0;
+	}
+}
+
+static bool
+key_cmp(const dns_rrl_key_t *a, const dns_rrl_key_t *b) {
+	if (memcmp(a, b, sizeof(dns_rrl_key_t)) == 0) {
+		return (true);
+	}
+	return (false);
+}
+
+static uint32_t
+hash_key(const dns_rrl_key_t *key) {
+	uint32_t hval;
+	int i;
+
+	hval = key->w[0];
+	for (i = sizeof(key->w) / sizeof(key->w[0]) - 1; i >= 0; --i) {
+		hval = key->w[i] + (hval << 1);
+	}
+	return (hval);
+}
+
+/*
+ * Construct the hash table key.
+ * Use a hash of the DNS query name to save space in the database.
+ * Collisions result in legitimate rate limiting responses for one
+ * query name also limiting responses for other names to the
+ * same client.  This is rare and benign enough given the large
+ * space costs compared to keeping the entire name in the database
+ * entry or the time costs of dynamic allocation.
+ */
+static void
+make_key(const dns_rrl_t *rrl, dns_rrl_key_t *key,
+	 const isc_sockaddr_t *client_addr, dns_zone_t *zone,
+	 dns_rdatatype_t qtype, const dns_name_t *qname,
+	 dns_rdataclass_t qclass, dns_rrl_rtype_t rtype) {
+	int i;
+
+	memset(key, 0, sizeof(*key));
+
+	key->s.rtype = rtype;
+	if (rtype == DNS_RRL_RTYPE_QUERY) {
+		key->s.qtype = qtype;
+		key->s.qclass = qclass & 0xff;
+	} else if (rtype == DNS_RRL_RTYPE_REFERRAL ||
+		   rtype == DNS_RRL_RTYPE_NODATA)
+	{
+		/*
+		 * Because there is no qtype in the empty answer sections of
+		 * referral and NODATA responses, count them as the same.
+		 */
+		key->s.qclass = qclass & 0xff;
+	}
+
+	if (qname != NULL && qname->labels != 0) {
+		dns_name_t *origin = NULL;
+
+		if ((qname->attributes & DNS_NAMEATTR_WILDCARD) != 0 &&
+		    zone != NULL && (origin = dns_zone_getorigin(zone)) != NULL)
+		{
+			dns_fixedname_t fixed;
+			dns_name_t *wild;
+			isc_result_t result;
+
+			/*
+			 * Put all wildcard names in one bucket using the zone's
+			 * origin name concatenated to the "*" name.
+			 */
+			wild = dns_fixedname_initname(&fixed);
+			result = dns_name_concatenate(dns_wildcardname, origin,
+						      wild, NULL);
+			if (result != ISC_R_SUCCESS) {
+				/*
+				 * Fallback to use the zone's origin name
+				 * instead of the concatenated name.
+				 */
+				wild = origin;
+			}
+			key->s.qname_hash = dns_name_fullhash(wild, false);
+		} else {
+			key->s.qname_hash = dns_name_fullhash(qname, false);
+		}
+	}
+
+	switch (client_addr->type.sa.sa_family) {
+	case AF_INET:
+		key->s.ip[0] = (client_addr->type.sin.sin_addr.s_addr &
+				rrl->ipv4_mask);
+		break;
+	case AF_INET6:
+		key->s.ipv6 = true;
+		memmove(key->s.ip, &client_addr->type.sin6.sin6_addr,
+			sizeof(key->s.ip));
+		for (i = 0; i < DNS_RRL_MAX_PREFIX / 32; ++i) {
+			key->s.ip[i] &= rrl->ipv6_mask[i];
+		}
+		break;
+	}
+}
+
+static dns_rrl_rate_t *
+get_rate(dns_rrl_t *rrl, dns_rrl_rtype_t rtype) {
+	switch (rtype) {
+	case DNS_RRL_RTYPE_QUERY:
+		return (&rrl->responses_per_second);
+	case DNS_RRL_RTYPE_REFERRAL:
+		return (&rrl->referrals_per_second);
+	case DNS_RRL_RTYPE_NODATA:
+		return (&rrl->nodata_per_second);
+	case DNS_RRL_RTYPE_NXDOMAIN:
+		return (&rrl->nxdomains_per_second);
+	case DNS_RRL_RTYPE_ERROR:
+		return (&rrl->errors_per_second);
+	case DNS_RRL_RTYPE_ALL:
+		return (&rrl->all_per_second);
+	default:
+		UNREACHABLE();
+	}
+}
+
+static int
+response_balance(dns_rrl_t *rrl, const dns_rrl_entry_t *e, int age) {
+	dns_rrl_rate_t *ratep;
+	int balance, rate;
+
+	if (e->key.s.rtype == DNS_RRL_RTYPE_TCP) {
+		rate = 1;
+	} else {
+		ratep = get_rate(rrl, e->key.s.rtype);
+		rate = ratep->scaled;
+	}
+
+	balance = e->responses + age * rate;
+	if (balance > rate) {
+		balance = rate;
+	}
+	return (balance);
+}
+
+/*
+ * Search for an entry for a response and optionally create it.
+ */
+static dns_rrl_entry_t *
+get_entry(dns_rrl_t *rrl, const isc_sockaddr_t *client_addr, dns_zone_t *zone,
+	  dns_rdataclass_t qclass, dns_rdatatype_t qtype,
+	  const dns_name_t *qname, dns_rrl_rtype_t rtype, isc_stdtime_t now,
+	  bool create, char *log_buf, unsigned int log_buf_len) {
+	dns_rrl_key_t key;
+	uint32_t hval;
+	dns_rrl_entry_t *e;
+	dns_rrl_hash_t *hash;
+	dns_rrl_bin_t *new_bin, *old_bin;
+	int probes, age;
+
+	make_key(rrl, &key, client_addr, zone, qtype, qname, qclass, rtype);
+	hval = hash_key(&key);
+
+	/*
+	 * Look for the entry in the current hash table.
+	 */
+	new_bin = get_bin(rrl->hash, hval);
+	probes = 1;
+	e = ISC_LIST_HEAD(*new_bin);
+	while (e != NULL) {
+		if (key_cmp(&e->key, &key)) {
+			ref_entry(rrl, e, probes, now);
+			return (e);
+		}
+		++probes;
+		e = ISC_LIST_NEXT(e, hlink);
+	}
+
+	/*
+	 * Look in the old hash table.
+	 */
+	if (rrl->old_hash != NULL) {
+		old_bin = get_bin(rrl->old_hash, hval);
+		e = ISC_LIST_HEAD(*old_bin);
+		while (e != NULL) {
+			if (key_cmp(&e->key, &key)) {
+				ISC_LIST_UNLINK(*old_bin, e, hlink);
+				ISC_LIST_PREPEND(*new_bin, e, hlink);
+				e->hash_gen = rrl->hash_gen;
+				ref_entry(rrl, e, probes, now);
+				return (e);
+			}
+			e = ISC_LIST_NEXT(e, hlink);
+		}
+
+		/*
+		 * Discard previous hash table when all of its entries are old.
+		 */
+		age = delta_rrl_time(rrl->old_hash->check_time, now);
+		if (age > rrl->window) {
+			free_old_hash(rrl);
+		}
+	}
+
+	if (!create) {
+		return (NULL);
+	}
+
+	/*
+	 * The entry does not exist, so create it by finding a free entry.
+	 * Keep currently penalized and logged entries.
+	 * Try to make more entries if none are idle.
+	 * Steal the oldest entry if we cannot create more.
+	 */
+	for (e = ISC_LIST_TAIL(rrl->lru); e != NULL; e = ISC_LIST_PREV(e, lru))
+	{
+		if (!ISC_LINK_LINKED(e, hlink)) {
+			break;
+		}
+		age = get_age(rrl, e, now);
+		if (age <= 1) {
+			e = NULL;
+			break;
+		}
+		if (!e->logged && response_balance(rrl, e, age) > 0) {
+			break;
+		}
+	}
+	if (e == NULL) {
+		expand_entries(rrl, ISC_MIN((rrl->num_entries + 1) / 2, 1000));
+		e = ISC_LIST_TAIL(rrl->lru);
+	}
+	if (e->logged) {
+		log_end(rrl, e, true, log_buf, log_buf_len);
+	}
+	if (ISC_LINK_LINKED(e, hlink)) {
+		if (e->hash_gen == rrl->hash_gen) {
+			hash = rrl->hash;
+		} else {
+			hash = rrl->old_hash;
+		}
+		old_bin = get_bin(hash, hash_key(&e->key));
+		ISC_LIST_UNLINK(*old_bin, e, hlink);
+	}
+	ISC_LIST_PREPEND(*new_bin, e, hlink);
+	e->hash_gen = rrl->hash_gen;
+	e->key = key;
+	e->ts_valid = false;
+	ref_entry(rrl, e, probes, now);
+	return (e);
+}
+
+static void
+debit_log(const dns_rrl_entry_t *e, int age, const char *action) {
+	char buf[sizeof("age=2147483647")];
+	const char *age_str;
+
+	if (age == DNS_RRL_FOREVER) {
+		age_str = "";
+	} else {
+		snprintf(buf, sizeof(buf), "age=%d", age);
+		age_str = buf;
+	}
+	isc_log_write(dns_lctx, DNS_LOGCATEGORY_RRL, DNS_LOGMODULE_REQUEST,
+		      DNS_RRL_LOG_DEBUG3, "rrl %08x %6s  responses=%-3d %s",
+		      hash_key(&e->key), age_str, e->responses, action);
+}
+
+static dns_rrl_result_t
+debit_rrl_entry(dns_rrl_t *rrl, dns_rrl_entry_t *e, double qps, double scale,
+		const isc_sockaddr_t *client_addr, isc_stdtime_t now,
+		char *log_buf, unsigned int log_buf_len) {
+	int rate, new_rate, slip, new_slip, age, log_secs, min;
+	dns_rrl_rate_t *ratep;
+	dns_rrl_entry_t const *credit_e;
+
+	/*
+	 * Pick the rate counter.
+	 * Optionally adjust the rate by the estimated query/second rate.
+	 */
+	ratep = get_rate(rrl, e->key.s.rtype);
+	rate = ratep->r;
+	if (rate == 0) {
+		return (DNS_RRL_RESULT_OK);
+	}
+
+	if (scale < 1.0) {
+		/*
+		 * The limit for clients that have used TCP is not scaled.
+		 */
+		credit_e = get_entry(
+			rrl, client_addr, NULL, 0, dns_rdatatype_none, NULL,
+			DNS_RRL_RTYPE_TCP, now, false, log_buf, log_buf_len);
+		if (credit_e != NULL) {
+			age = get_age(rrl, e, now);
+			if (age < rrl->window) {
+				scale = 1.0;
+			}
+		}
+	}
+	if (scale < 1.0) {
+		new_rate = (int)(rate * scale);
+		if (new_rate < 1) {
+			new_rate = 1;
+		}
+		if (ratep->scaled != new_rate) {
+			isc_log_write(dns_lctx, DNS_LOGCATEGORY_RRL,
+				      DNS_LOGMODULE_REQUEST, DNS_RRL_LOG_DEBUG1,
+				      "%d qps scaled %s by %.2f"
+				      " from %d to %d",
+				      (int)qps, ratep->str, scale, rate,
+				      new_rate);
+			rate = new_rate;
+			ratep->scaled = rate;
+		}
+	}
+
+	min = -rrl->window * rate;
+
+	/*
+	 * Treat time jumps into the recent past as no time.
+	 * Treat entries older than the window as if they were just created
+	 * Credit other entries.
+	 */
+	age = get_age(rrl, e, now);
+	if (age > 0) {
+		/*
+		 * Credit tokens earned during elapsed time.
+		 */
+		if (age > rrl->window) {
+			e->responses = rate;
+			e->slip_cnt = 0;
+		} else {
+			e->responses += rate * age;
+			if (e->responses > rate) {
+				e->responses = rate;
+				e->slip_cnt = 0;
+			}
+		}
+		/*
+		 * Find the seconds since last log message without overflowing
+		 * small counter.  This counter is reset when an entry is
+		 * created.  It is not necessarily reset when some requests
+		 * are answered provided other requests continue to be dropped
+		 * or slipped.  This can happen when the request rate is just
+		 * at the limit.
+		 */
+		if (e->logged) {
+			log_secs = e->log_secs;
+			log_secs += age;
+			if (log_secs > DNS_RRL_MAX_LOG_SECS || log_secs < 0) {
+				log_secs = DNS_RRL_MAX_LOG_SECS;
+			}
+			e->log_secs = log_secs;
+		}
+	}
+	set_age(rrl, e, now);
+
+	/*
+	 * Debit the entry for this response.
+	 */
+	if (--e->responses >= 0) {
+		if (isc_log_wouldlog(dns_lctx, DNS_RRL_LOG_DEBUG3)) {
+			debit_log(e, age, "");
+		}
+		return (DNS_RRL_RESULT_OK);
+	}
+
+	if (e->responses < min) {
+		e->responses = min;
+	}
+
+	/*
+	 * Drop this response unless it should slip or leak.
+	 */
+	slip = rrl->slip.r;
+	if (slip > 2 && scale < 1.0) {
+		new_slip = (int)(slip * scale);
+		if (new_slip < 2) {
+			new_slip = 2;
+		}
+		if (rrl->slip.scaled != new_slip) {
+			isc_log_write(dns_lctx, DNS_LOGCATEGORY_RRL,
+				      DNS_LOGMODULE_REQUEST, DNS_RRL_LOG_DEBUG1,
+				      "%d qps scaled slip"
+				      " by %.2f from %d to %d",
+				      (int)qps, scale, slip, new_slip);
+			slip = new_slip;
+			rrl->slip.scaled = slip;
+		}
+	}
+	if (slip != 0 && e->key.s.rtype != DNS_RRL_RTYPE_ALL) {
+		if (e->slip_cnt++ == 0) {
+			if ((int)e->slip_cnt >= slip) {
+				e->slip_cnt = 0;
+			}
+			if (isc_log_wouldlog(dns_lctx, DNS_RRL_LOG_DEBUG3)) {
+				debit_log(e, age, "slip");
+			}
+			return (DNS_RRL_RESULT_SLIP);
+		} else if ((int)e->slip_cnt >= slip) {
+			e->slip_cnt = 0;
+		}
+	}
+
+	if (isc_log_wouldlog(dns_lctx, DNS_RRL_LOG_DEBUG3)) {
+		debit_log(e, age, "drop");
+	}
+	return (DNS_RRL_RESULT_DROP);
+}
+
+static dns_rrl_qname_buf_t *
+get_qname(dns_rrl_t *rrl, const dns_rrl_entry_t *e) {
+	dns_rrl_qname_buf_t *qbuf;
+
+	qbuf = rrl->qnames[e->log_qname];
+	if (qbuf == NULL || qbuf->e != e) {
+		return (NULL);
+	}
+	return (qbuf);
+}
+
+static void
+free_qname(dns_rrl_t *rrl, dns_rrl_entry_t *e) {
+	dns_rrl_qname_buf_t *qbuf;
+
+	qbuf = get_qname(rrl, e);
+	if (qbuf != NULL) {
+		qbuf->e = NULL;
+		ISC_LIST_APPEND(rrl->qname_free, qbuf, link);
+	}
+}
+
+static void
+add_log_str(isc_buffer_t *lb, const char *str, unsigned int str_len) {
+	isc_region_t region;
+
+	isc_buffer_availableregion(lb, &region);
+	if (str_len >= region.length) {
+		if (region.length == 0U) {
+			return;
+		}
+		str_len = region.length;
+	}
+	memmove(region.base, str, str_len);
+	isc_buffer_add(lb, str_len);
+}
+
+#define ADD_LOG_CSTR(eb, s) add_log_str(eb, s, sizeof(s) - 1)
+
+/*
+ * Build strings for the logs
+ */
+static void
+make_log_buf(dns_rrl_t *rrl, dns_rrl_entry_t *e, const char *str1,
+	     const char *str2, bool plural, const dns_name_t *qname,
+	     bool save_qname, dns_rrl_result_t rrl_result,
+	     isc_result_t resp_result, char *log_buf,
+	     unsigned int log_buf_len) {
+	isc_buffer_t lb;
+	dns_rrl_qname_buf_t *qbuf;
+	isc_netaddr_t cidr;
+	char strbuf[ISC_MAX(sizeof("/123"), sizeof("  (12345678)"))];
+	const char *rstr;
+	isc_result_t msg_result;
+
+	if (log_buf_len <= 1) {
+		if (log_buf_len == 1) {
+			log_buf[0] = '\0';
+		}
+		return;
+	}
+	isc_buffer_init(&lb, log_buf, log_buf_len - 1);
+
+	if (str1 != NULL) {
+		add_log_str(&lb, str1, strlen(str1));
+	}
+	if (str2 != NULL) {
+		add_log_str(&lb, str2, strlen(str2));
+	}
+
+	switch (rrl_result) {
+	case DNS_RRL_RESULT_OK:
+		break;
+	case DNS_RRL_RESULT_DROP:
+		ADD_LOG_CSTR(&lb, "drop ");
+		break;
+	case DNS_RRL_RESULT_SLIP:
+		ADD_LOG_CSTR(&lb, "slip ");
+		break;
+	default:
+		UNREACHABLE();
+	}
+
+	switch (e->key.s.rtype) {
+	case DNS_RRL_RTYPE_QUERY:
+		break;
+	case DNS_RRL_RTYPE_REFERRAL:
+		ADD_LOG_CSTR(&lb, "referral ");
+		break;
+	case DNS_RRL_RTYPE_NODATA:
+		ADD_LOG_CSTR(&lb, "NODATA ");
+		break;
+	case DNS_RRL_RTYPE_NXDOMAIN:
+		ADD_LOG_CSTR(&lb, "NXDOMAIN ");
+		break;
+	case DNS_RRL_RTYPE_ERROR:
+		if (resp_result == ISC_R_SUCCESS) {
+			ADD_LOG_CSTR(&lb, "error ");
+		} else {
+			rstr = isc_result_totext(resp_result);
+			add_log_str(&lb, rstr, strlen(rstr));
+			ADD_LOG_CSTR(&lb, " error ");
+		}
+		break;
+	case DNS_RRL_RTYPE_ALL:
+		ADD_LOG_CSTR(&lb, "all ");
+		break;
+	default:
+		UNREACHABLE();
+	}
+
+	if (plural) {
+		ADD_LOG_CSTR(&lb, "responses to ");
+	} else {
+		ADD_LOG_CSTR(&lb, "response to ");
+	}
+
+	memset(&cidr, 0, sizeof(cidr));
+	if (e->key.s.ipv6) {
+		snprintf(strbuf, sizeof(strbuf), "/%d", rrl->ipv6_prefixlen);
+		cidr.family = AF_INET6;
+		memset(&cidr.type.in6, 0, sizeof(cidr.type.in6));
+		memmove(&cidr.type.in6, e->key.s.ip, sizeof(e->key.s.ip));
+	} else {
+		snprintf(strbuf, sizeof(strbuf), "/%d", rrl->ipv4_prefixlen);
+		cidr.family = AF_INET;
+		cidr.type.in.s_addr = e->key.s.ip[0];
+	}
+	msg_result = isc_netaddr_totext(&cidr, &lb);
+	if (msg_result != ISC_R_SUCCESS) {
+		ADD_LOG_CSTR(&lb, "?");
+	}
+	add_log_str(&lb, strbuf, strlen(strbuf));
+
+	if (e->key.s.rtype == DNS_RRL_RTYPE_QUERY ||
+	    e->key.s.rtype == DNS_RRL_RTYPE_REFERRAL ||
+	    e->key.s.rtype == DNS_RRL_RTYPE_NODATA ||
+	    e->key.s.rtype == DNS_RRL_RTYPE_NXDOMAIN)
+	{
+		qbuf = get_qname(rrl, e);
+		if (save_qname && qbuf == NULL && qname != NULL &&
+		    dns_name_isabsolute(qname))
+		{
+			/*
+			 * Capture the qname for the "stop limiting" message.
+			 */
+			qbuf = ISC_LIST_TAIL(rrl->qname_free);
+			if (qbuf != NULL) {
+				ISC_LIST_UNLINK(rrl->qname_free, qbuf, link);
+			} else if (rrl->num_qnames < DNS_RRL_QNAMES) {
+				qbuf = isc_mem_get(rrl->mctx, sizeof(*qbuf));
+				{
+					memset(qbuf, 0, sizeof(*qbuf));
+					ISC_LINK_INIT(qbuf, link);
+					qbuf->index = rrl->num_qnames;
+					rrl->qnames[rrl->num_qnames++] = qbuf;
+				}
+			}
+			if (qbuf != NULL) {
+				e->log_qname = qbuf->index;
+				qbuf->e = e;
+				dns_fixedname_init(&qbuf->qname);
+				dns_name_copynf(qname, dns_fixedname_name(
+							       &qbuf->qname));
+			}
+		}
+		if (qbuf != NULL) {
+			qname = dns_fixedname_name(&qbuf->qname);
+		}
+		if (qname != NULL) {
+			ADD_LOG_CSTR(&lb, " for ");
+			(void)dns_name_totext(qname, true, &lb);
+		} else {
+			ADD_LOG_CSTR(&lb, " for (?)");
+		}
+		if (e->key.s.rtype != DNS_RRL_RTYPE_NXDOMAIN) {
+			ADD_LOG_CSTR(&lb, " ");
+			(void)dns_rdataclass_totext(e->key.s.qclass, &lb);
+			if (e->key.s.rtype == DNS_RRL_RTYPE_QUERY) {
+				ADD_LOG_CSTR(&lb, " ");
+				(void)dns_rdatatype_totext(e->key.s.qtype, &lb);
+			}
+		}
+		snprintf(strbuf, sizeof(strbuf), "  (%08" PRIx32 ")",
+			 e->key.s.qname_hash);
+		add_log_str(&lb, strbuf, strlen(strbuf));
+	}
+
+	/*
+	 * We saved room for '\0'.
+	 */
+	log_buf[isc_buffer_usedlength(&lb)] = '\0';
+}
+
+static void
+log_end(dns_rrl_t *rrl, dns_rrl_entry_t *e, bool early, char *log_buf,
+	unsigned int log_buf_len) {
+	if (e->logged) {
+		make_log_buf(rrl, e, early ? "*" : NULL,
+			     rrl->log_only ? "would stop limiting "
+					   : "stop limiting ",
+			     true, NULL, false, DNS_RRL_RESULT_OK,
+			     ISC_R_SUCCESS, log_buf, log_buf_len);
+		isc_log_write(dns_lctx, DNS_LOGCATEGORY_RRL,
+			      DNS_LOGMODULE_REQUEST, DNS_RRL_LOG_DROP, "%s",
+			      log_buf);
+		free_qname(rrl, e);
+		e->logged = false;
+		--rrl->num_logged;
+	}
+}
+
+/*
+ * Log messages for streams that have stopped being rate limited.
+ */
+static void
+log_stops(dns_rrl_t *rrl, isc_stdtime_t now, int limit, char *log_buf,
+	  unsigned int log_buf_len) {
+	dns_rrl_entry_t *e;
+	int age;
+
+	for (e = rrl->last_logged; e != NULL; e = ISC_LIST_PREV(e, lru)) {
+		if (!e->logged) {
+			continue;
+		}
+		if (now != 0) {
+			age = get_age(rrl, e, now);
+			if (age < DNS_RRL_STOP_LOG_SECS ||
+			    response_balance(rrl, e, age) < 0)
+			{
+				break;
+			}
+		}
+
+		log_end(rrl, e, now == 0, log_buf, log_buf_len);
+		if (rrl->num_logged <= 0) {
+			break;
+		}
+
+		/*
+		 * Too many messages could stall real work.
+		 */
+		if (--limit < 0) {
+			rrl->last_logged = ISC_LIST_PREV(e, lru);
+			return;
+		}
+	}
+	if (e == NULL) {
+		INSIST(rrl->num_logged == 0);
+		rrl->log_stops_time = now;
+	}
+	rrl->last_logged = e;
+}
+
+/*
+ * Main rate limit interface.
+ */
+dns_rrl_result_t
+dns_rrl(dns_view_t *view, dns_zone_t *zone, const isc_sockaddr_t *client_addr,
+	bool is_tcp, dns_rdataclass_t qclass, dns_rdatatype_t qtype,
+	const dns_name_t *qname, isc_result_t resp_result, isc_stdtime_t now,
+	bool wouldlog, char *log_buf, unsigned int log_buf_len) {
+	dns_rrl_t *rrl;
+	dns_rrl_rtype_t rtype;
+	dns_rrl_entry_t *e;
+	isc_netaddr_t netclient;
+	int secs;
+	double qps, scale;
+	int exempt_match;
+	isc_result_t result;
+	dns_rrl_result_t rrl_result;
+
+	INSIST(log_buf != NULL && log_buf_len > 0);
+
+	rrl = view->rrl;
+	if (rrl->exempt != NULL) {
+		isc_netaddr_fromsockaddr(&netclient, client_addr);
+		result = dns_acl_match(&netclient, NULL, rrl->exempt,
+				       &view->aclenv, &exempt_match, NULL);
+		if (result == ISC_R_SUCCESS && exempt_match > 0) {
+			return (DNS_RRL_RESULT_OK);
+		}
+	}
+
+	LOCK(&rrl->lock);
+
+	/*
+	 * Estimate total query per second rate when scaling by qps.
+	 */
+	if (rrl->qps_scale == 0) {
+		qps = 0.0;
+		scale = 1.0;
+	} else {
+		++rrl->qps_responses;
+		secs = delta_rrl_time(rrl->qps_time, now);
+		if (secs <= 0) {
+			qps = rrl->qps;
+		} else {
+			qps = (1.0 * rrl->qps_responses) / secs;
+			if (secs >= rrl->window) {
+				if (isc_log_wouldlog(dns_lctx,
+						     DNS_RRL_LOG_DEBUG3))
+				{
+					isc_log_write(dns_lctx,
+						      DNS_LOGCATEGORY_RRL,
+						      DNS_LOGMODULE_REQUEST,
+						      DNS_RRL_LOG_DEBUG3,
+						      "%d responses/%d seconds"
+						      " = %d qps",
+						      rrl->qps_responses, secs,
+						      (int)qps);
+				}
+				rrl->qps = qps;
+				rrl->qps_responses = 0;
+				rrl->qps_time = now;
+			} else if (qps < rrl->qps) {
+				qps = rrl->qps;
+			}
+		}
+		scale = rrl->qps_scale / qps;
+	}
+
+	/*
+	 * Do maintenance once per second.
+	 */
+	if (rrl->num_logged > 0 && rrl->log_stops_time != now) {
+		log_stops(rrl, now, 8, log_buf, log_buf_len);
+	}
+
+	/*
+	 * Notice TCP responses when scaling limits by qps.
+	 * Do not try to rate limit TCP responses.
+	 */
+	if (is_tcp) {
+		if (scale < 1.0) {
+			e = get_entry(rrl, client_addr, NULL, 0,
+				      dns_rdatatype_none, NULL,
+				      DNS_RRL_RTYPE_TCP, now, true, log_buf,
+				      log_buf_len);
+			if (e != NULL) {
+				e->responses = -(rrl->window + 1);
+				set_age(rrl, e, now);
+			}
+		}
+		UNLOCK(&rrl->lock);
+		return (ISC_R_SUCCESS);
+	}
+
+	/*
+	 * Find the right kind of entry, creating it if necessary.
+	 * If that is impossible, then nothing more can be done
+	 */
+	switch (resp_result) {
+	case ISC_R_SUCCESS:
+		rtype = DNS_RRL_RTYPE_QUERY;
+		break;
+	case DNS_R_DELEGATION:
+		rtype = DNS_RRL_RTYPE_REFERRAL;
+		break;
+	case DNS_R_NXRRSET:
+		rtype = DNS_RRL_RTYPE_NODATA;
+		break;
+	case DNS_R_NXDOMAIN:
+		rtype = DNS_RRL_RTYPE_NXDOMAIN;
+		break;
+	default:
+		rtype = DNS_RRL_RTYPE_ERROR;
+		break;
+	}
+	e = get_entry(rrl, client_addr, zone, qclass, qtype, qname, rtype, now,
+		      true, log_buf, log_buf_len);
+	if (e == NULL) {
+		UNLOCK(&rrl->lock);
+		return (DNS_RRL_RESULT_OK);
+	}
+
+	if (isc_log_wouldlog(dns_lctx, DNS_RRL_LOG_DEBUG1)) {
+		/*
+		 * Do not worry about speed or releasing the lock.
+		 * This message appears before messages from debit_rrl_entry().
+		 */
+		make_log_buf(rrl, e, "consider limiting ", NULL, false, qname,
+			     false, DNS_RRL_RESULT_OK, resp_result, log_buf,
+			     log_buf_len);
+		isc_log_write(dns_lctx, DNS_LOGCATEGORY_RRL,
+			      DNS_LOGMODULE_REQUEST, DNS_RRL_LOG_DEBUG1, "%s",
+			      log_buf);
+	}
+
+	rrl_result = debit_rrl_entry(rrl, e, qps, scale, client_addr, now,
+				     log_buf, log_buf_len);
+
+	if (rrl->all_per_second.r != 0) {
+		/*
+		 * We must debit the all-per-second token bucket if we have
+		 * an all-per-second limit for the IP address.
+		 * The all-per-second limit determines the log message
+		 * when both limits are hit.
+		 * The response limiting must continue if the
+		 * all-per-second limiting lapses.
+		 */
+		dns_rrl_entry_t *e_all;
+		dns_rrl_result_t rrl_all_result;
+
+		e_all = get_entry(rrl, client_addr, zone, 0, dns_rdatatype_none,
+				  NULL, DNS_RRL_RTYPE_ALL, now, true, log_buf,
+				  log_buf_len);
+		if (e_all == NULL) {
+			UNLOCK(&rrl->lock);
+			return (DNS_RRL_RESULT_OK);
+		}
+		rrl_all_result = debit_rrl_entry(rrl, e_all, qps, scale,
+						 client_addr, now, log_buf,
+						 log_buf_len);
+		if (rrl_all_result != DNS_RRL_RESULT_OK) {
+			e = e_all;
+			rrl_result = rrl_all_result;
+			if (isc_log_wouldlog(dns_lctx, DNS_RRL_LOG_DEBUG1)) {
+				make_log_buf(rrl, e,
+					     "prefer all-per-second limiting ",
+					     NULL, true, qname, false,
+					     DNS_RRL_RESULT_OK, resp_result,
+					     log_buf, log_buf_len);
+				isc_log_write(dns_lctx, DNS_LOGCATEGORY_RRL,
+					      DNS_LOGMODULE_REQUEST,
+					      DNS_RRL_LOG_DEBUG1, "%s",
+					      log_buf);
+			}
+		}
+	}
+
+	if (rrl_result == DNS_RRL_RESULT_OK) {
+		UNLOCK(&rrl->lock);
+		return (DNS_RRL_RESULT_OK);
+	}
+
+	/*
+	 * Log occasionally in the rate-limit category.
+	 */
+	if ((!e->logged || e->log_secs >= DNS_RRL_MAX_LOG_SECS) &&
+	    isc_log_wouldlog(dns_lctx, DNS_RRL_LOG_DROP))
+	{
+		make_log_buf(rrl, e, rrl->log_only ? "would " : NULL,
+			     e->logged ? "continue limiting " : "limit ", true,
+			     qname, true, DNS_RRL_RESULT_OK, resp_result,
+			     log_buf, log_buf_len);
+		if (!e->logged) {
+			e->logged = true;
+			if (++rrl->num_logged <= 1) {
+				rrl->last_logged = e;
+			}
+		}
+		e->log_secs = 0;
+
+		/*
+		 * Avoid holding the lock.
+		 */
+		if (!wouldlog) {
+			UNLOCK(&rrl->lock);
+			e = NULL;
+		}
+		isc_log_write(dns_lctx, DNS_LOGCATEGORY_RRL,
+			      DNS_LOGMODULE_REQUEST, DNS_RRL_LOG_DROP, "%s",
+			      log_buf);
+	}
+
+	/*
+	 * Make a log message for the caller.
+	 */
+	if (wouldlog) {
+		make_log_buf(rrl, e,
+			     rrl->log_only ? "would rate limit "
+					   : "rate limit ",
+			     NULL, false, qname, false, rrl_result, resp_result,
+			     log_buf, log_buf_len);
+	}
+
+	if (e != NULL) {
+		/*
+		 * Do not save the qname unless we might need it for
+		 * the ending log message.
+		 */
+		if (!e->logged) {
+			free_qname(rrl, e);
+		}
+		UNLOCK(&rrl->lock);
+	}
+
+	return (rrl_result);
+}
+
+void
+dns_rrl_view_destroy(dns_view_t *view) {
+	dns_rrl_t *rrl;
+	dns_rrl_block_t *b;
+	dns_rrl_hash_t *h;
+	char log_buf[DNS_RRL_LOG_BUF_LEN];
+	int i;
+
+	rrl = view->rrl;
+	if (rrl == NULL) {
+		return;
+	}
+	view->rrl = NULL;
+
+	/*
+	 * Assume the caller takes care of locking the view and anything else.
+	 */
+
+	if (rrl->num_logged > 0) {
+		log_stops(rrl, 0, INT32_MAX, log_buf, sizeof(log_buf));
+	}
+
+	for (i = 0; i < DNS_RRL_QNAMES; ++i) {
+		if (rrl->qnames[i] == NULL) {
+			break;
+		}
+		isc_mem_put(rrl->mctx, rrl->qnames[i], sizeof(*rrl->qnames[i]));
+	}
+
+	if (rrl->exempt != NULL) {
+		dns_acl_detach(&rrl->exempt);
+	}
+
+	isc_mutex_destroy(&rrl->lock);
+
+	while (!ISC_LIST_EMPTY(rrl->blocks)) {
+		b = ISC_LIST_HEAD(rrl->blocks);
+		ISC_LIST_UNLINK(rrl->blocks, b, link);
+		isc_mem_put(rrl->mctx, b, b->size);
+	}
+
+	h = rrl->hash;
+	if (h != NULL) {
+		isc_mem_put(rrl->mctx, h,
+			    sizeof(*h) + (h->length - 1) * sizeof(h->bins[0]));
+	}
+
+	h = rrl->old_hash;
+	if (h != NULL) {
+		isc_mem_put(rrl->mctx, h,
+			    sizeof(*h) + (h->length - 1) * sizeof(h->bins[0]));
+	}
+
+	isc_mem_putanddetach(&rrl->mctx, rrl, sizeof(*rrl));
+}
+
+isc_result_t
+dns_rrl_init(dns_rrl_t **rrlp, dns_view_t *view, int min_entries) {
+	dns_rrl_t *rrl;
+	isc_result_t result;
+
+	*rrlp = NULL;
+
+	rrl = isc_mem_get(view->mctx, sizeof(*rrl));
+	memset(rrl, 0, sizeof(*rrl));
+	isc_mem_attach(view->mctx, &rrl->mctx);
+	isc_mutex_init(&rrl->lock);
+	isc_stdtime_get(&rrl->ts_bases[0]);
+
+	view->rrl = rrl;
+
+	result = expand_entries(rrl, min_entries);
+	if (result != ISC_R_SUCCESS) {
+		dns_rrl_view_destroy(view);
+		return (result);
+	}
+	result = expand_rrl_hash(rrl, 0);
+	if (result != ISC_R_SUCCESS) {
+		dns_rrl_view_destroy(view);
+		return (result);
+	}
+
+	*rrlp = rrl;
+	return (ISC_R_SUCCESS);
+}