Adding upstream version 1:9.18.19.upstream/1%9.18.19upstream

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

1 files changed, 2647 insertions, 0 deletions

diff --git a/lib/dns/keymgr.c b/lib/dns/keymgr.c
new file mode 100644
index 0000000..106b376
--- /dev/null
+++ b/lib/dns/keymgr.c
@@ -0,0 +1,2647 @@
+/*
+ * 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 <unistd.h>
+
+#include <isc/buffer.h>
+#include <isc/dir.h>
+#include <isc/mem.h>
+#include <isc/print.h>
+#include <isc/result.h>
+#include <isc/string.h>
+#include <isc/util.h>
+
+#include <dns/dnssec.h>
+#include <dns/kasp.h>
+#include <dns/keymgr.h>
+#include <dns/keyvalues.h>
+#include <dns/log.h>
+
+#include <dst/dst.h>
+
+#define RETERR(x)                            \
+	do {                                 \
+		result = (x);                \
+		if (result != ISC_R_SUCCESS) \
+			goto failure;        \
+	} while (0)
+
+/*
+ * Set key state to `target` state and change last changed
+ * to `time`, only if key state has not been set before.
+ */
+#define INITIALIZE_STATE(key, state, timing, target, time)                     \
+	do {                                                                   \
+		dst_key_state_t s;                                             \
+		char keystr[DST_KEY_FORMATSIZE];                               \
+		if (dst_key_getstate((key), (state), &s) == ISC_R_NOTFOUND) {  \
+			dst_key_setstate((key), (state), (target));            \
+			dst_key_settime((key), (timing), time);                \
+                                                                               \
+			if (isc_log_wouldlog(dns_lctx, ISC_LOG_DEBUG(1))) {    \
+				dst_key_format((key), keystr, sizeof(keystr)); \
+				isc_log_write(                                 \
+					dns_lctx, DNS_LOGCATEGORY_DNSSEC,      \
+					DNS_LOGMODULE_DNSSEC,                  \
+					ISC_LOG_DEBUG(3),                      \
+					"keymgr: DNSKEY %s (%s) initialize "   \
+					"%s state to %s (policy %s)",          \
+					keystr, keymgr_keyrole((key)),         \
+					keystatetags[state],                   \
+					keystatestrings[target],               \
+					dns_kasp_getname(kasp));               \
+			}                                                      \
+		}                                                              \
+	} while (0)
+
+/* Shorter keywords for better readability. */
+#define HIDDEN	    DST_KEY_STATE_HIDDEN
+#define RUMOURED    DST_KEY_STATE_RUMOURED
+#define OMNIPRESENT DST_KEY_STATE_OMNIPRESENT
+#define UNRETENTIVE DST_KEY_STATE_UNRETENTIVE
+#define NA	    DST_KEY_STATE_NA
+
+/* Quickly get key state timing metadata. */
+#define NUM_KEYSTATES (DST_MAX_KEYSTATES)
+static int keystatetimes[NUM_KEYSTATES] = { DST_TIME_DNSKEY, DST_TIME_ZRRSIG,
+					    DST_TIME_KRRSIG, DST_TIME_DS };
+/* Readable key state types and values. */
+static const char *keystatetags[NUM_KEYSTATES] = { "DNSKEY", "ZRRSIG", "KRRSIG",
+						   "DS" };
+static const char *keystatestrings[4] = { "HIDDEN", "RUMOURED", "OMNIPRESENT",
+					  "UNRETENTIVE" };
+
+/*
+ * Print key role.
+ *
+ */
+static const char *
+keymgr_keyrole(dst_key_t *key) {
+	bool ksk = false, zsk = false;
+	isc_result_t ret;
+	ret = dst_key_getbool(key, DST_BOOL_KSK, &ksk);
+	if (ret != ISC_R_SUCCESS) {
+		return ("UNKNOWN");
+	}
+	ret = dst_key_getbool(key, DST_BOOL_ZSK, &zsk);
+	if (ret != ISC_R_SUCCESS) {
+		return ("UNKNOWN");
+	}
+	if (ksk && zsk) {
+		return ("CSK");
+	} else if (ksk) {
+		return ("KSK");
+	} else if (zsk) {
+		return ("ZSK");
+	}
+	return ("NOSIGN");
+}
+
+/*
+ * Set the remove time on key given its retire time.
+ *
+ */
+static void
+keymgr_settime_remove(dns_dnsseckey_t *key, dns_kasp_t *kasp) {
+	isc_stdtime_t retire = 0, remove = 0, ksk_remove = 0, zsk_remove = 0;
+	bool zsk = false, ksk = false;
+	isc_result_t ret;
+
+	REQUIRE(key != NULL);
+	REQUIRE(key->key != NULL);
+
+	ret = dst_key_gettime(key->key, DST_TIME_INACTIVE, &retire);
+	if (ret != ISC_R_SUCCESS) {
+		return;
+	}
+
+	ret = dst_key_getbool(key->key, DST_BOOL_ZSK, &zsk);
+	if (ret == ISC_R_SUCCESS && zsk) {
+		dns_ttl_t ttlsig = dns_kasp_zonemaxttl(kasp, true);
+		/* ZSK: Iret = Dsgn + Dprp + TTLsig */
+		zsk_remove =
+			retire + ttlsig + dns_kasp_zonepropagationdelay(kasp) +
+			dns_kasp_retiresafety(kasp) + dns_kasp_signdelay(kasp);
+	}
+	ret = dst_key_getbool(key->key, DST_BOOL_KSK, &ksk);
+	if (ret == ISC_R_SUCCESS && ksk) {
+		/* KSK: Iret = DprpP + TTLds */
+		ksk_remove = retire + dns_kasp_dsttl(kasp) +
+			     dns_kasp_parentpropagationdelay(kasp) +
+			     dns_kasp_retiresafety(kasp);
+	}
+
+	remove = ISC_MAX(ksk_remove, zsk_remove);
+	dst_key_settime(key->key, DST_TIME_DELETE, remove);
+}
+
+/*
+ * Set the SyncPublish time (when the DS may be submitted to the parent).
+ *
+ */
+static void
+keymgr_settime_syncpublish(dns_dnsseckey_t *key, dns_kasp_t *kasp, bool first) {
+	isc_stdtime_t published, syncpublish;
+	bool ksk = false;
+	isc_result_t ret;
+
+	REQUIRE(key != NULL);
+	REQUIRE(key->key != NULL);
+
+	ret = dst_key_gettime(key->key, DST_TIME_PUBLISH, &published);
+	if (ret != ISC_R_SUCCESS) {
+		return;
+	}
+
+	ret = dst_key_getbool(key->key, DST_BOOL_KSK, &ksk);
+	if (ret != ISC_R_SUCCESS || !ksk) {
+		return;
+	}
+
+	syncpublish = published + dst_key_getttl(key->key) +
+		      dns_kasp_zonepropagationdelay(kasp) +
+		      dns_kasp_publishsafety(kasp);
+	if (first) {
+		/* Also need to wait until the signatures are omnipresent. */
+		isc_stdtime_t zrrsig_present;
+		dns_ttl_t ttlsig = dns_kasp_zonemaxttl(kasp, true);
+		zrrsig_present = published + ttlsig +
+				 dns_kasp_zonepropagationdelay(kasp) +
+				 dns_kasp_publishsafety(kasp);
+		if (zrrsig_present > syncpublish) {
+			syncpublish = zrrsig_present;
+		}
+	}
+	dst_key_settime(key->key, DST_TIME_SYNCPUBLISH, syncpublish);
+}
+
+/*
+ * Calculate prepublication time of a successor key of 'key'.
+ * This function can have side effects:
+ * 1. If there is no active time set, which would be super weird, set it now.
+ * 2. If there is no published time set, also super weird, set it now.
+ * 3. If there is no syncpublished time set, set it now.
+ * 4. If the lifetime is not set, it will be set now.
+ * 5. If there should be a retire time and it is not set, it will be set now.
+ * 6. The removed time is adjusted accordingly.
+ *
+ * This returns when the successor key needs to be published in the zone.
+ * A special value of 0 means there is no need for a successor.
+ *
+ */
+static isc_stdtime_t
+keymgr_prepublication_time(dns_dnsseckey_t *key, dns_kasp_t *kasp,
+			   uint32_t lifetime, isc_stdtime_t now) {
+	isc_result_t ret;
+	isc_stdtime_t active, retire, pub, prepub;
+	bool zsk = false, ksk = false;
+
+	REQUIRE(key != NULL);
+	REQUIRE(key->key != NULL);
+
+	active = 0;
+	pub = 0;
+	retire = 0;
+
+	/*
+	 * An active key must have publish and activate timing
+	 * metadata.
+	 */
+	ret = dst_key_gettime(key->key, DST_TIME_ACTIVATE, &active);
+	if (ret != ISC_R_SUCCESS) {
+		/* Super weird, but if it happens, set it to now. */
+		dst_key_settime(key->key, DST_TIME_ACTIVATE, now);
+		active = now;
+	}
+	ret = dst_key_gettime(key->key, DST_TIME_PUBLISH, &pub);
+	if (ret != ISC_R_SUCCESS) {
+		/* Super weird, but if it happens, set it to now. */
+		dst_key_settime(key->key, DST_TIME_PUBLISH, now);
+		pub = now;
+	}
+
+	/*
+	 * Calculate prepublication time.
+	 */
+	prepub = dst_key_getttl(key->key) + dns_kasp_publishsafety(kasp) +
+		 dns_kasp_zonepropagationdelay(kasp);
+	ret = dst_key_getbool(key->key, DST_BOOL_KSK, &ksk);
+	if (ret == ISC_R_SUCCESS && ksk) {
+		isc_stdtime_t syncpub;
+
+		/*
+		 * Set PublishCDS if not set.
+		 */
+		ret = dst_key_gettime(key->key, DST_TIME_SYNCPUBLISH, &syncpub);
+		if (ret != ISC_R_SUCCESS) {
+			uint32_t tag;
+			isc_stdtime_t syncpub1, syncpub2;
+
+			syncpub1 = pub + prepub;
+			syncpub2 = 0;
+			ret = dst_key_getnum(key->key, DST_NUM_PREDECESSOR,
+					     &tag);
+			if (ret != ISC_R_SUCCESS) {
+				/*
+				 * No predecessor, wait for zone to be
+				 * completely signed.
+				 */
+				dns_ttl_t ttlsig = dns_kasp_zonemaxttl(kasp,
+								       true);
+				syncpub2 = pub + ttlsig +
+					   dns_kasp_publishsafety(kasp) +
+					   dns_kasp_zonepropagationdelay(kasp);
+			}
+
+			syncpub = ISC_MAX(syncpub1, syncpub2);
+			dst_key_settime(key->key, DST_TIME_SYNCPUBLISH,
+					syncpub);
+		}
+	}
+
+	/*
+	 * Not sure what to do when dst_key_getbool() fails here.  Extending
+	 * the prepublication time anyway is arguably the safest thing to do,
+	 * so ignore the result code.
+	 */
+	(void)dst_key_getbool(key->key, DST_BOOL_ZSK, &zsk);
+
+	ret = dst_key_gettime(key->key, DST_TIME_INACTIVE, &retire);
+	if (ret != ISC_R_SUCCESS) {
+		uint32_t klifetime = 0;
+
+		ret = dst_key_getnum(key->key, DST_NUM_LIFETIME, &klifetime);
+		if (ret != ISC_R_SUCCESS) {
+			dst_key_setnum(key->key, DST_NUM_LIFETIME, lifetime);
+			klifetime = lifetime;
+		}
+		if (klifetime == 0) {
+			/*
+			 * No inactive time and no lifetime,
+			 * so no need to start a rollover.
+			 */
+			return (0);
+		}
+
+		retire = active + klifetime;
+		dst_key_settime(key->key, DST_TIME_INACTIVE, retire);
+	}
+
+	/*
+	 * Update remove time.
+	 */
+	keymgr_settime_remove(key, kasp);
+
+	/*
+	 * Publish successor 'prepub' time before the 'retire' time of 'key'.
+	 */
+	if (prepub > retire) {
+		/* We should have already prepublished the new key. */
+		return (now);
+	}
+	return (retire - prepub);
+}
+
+static void
+keymgr_key_retire(dns_dnsseckey_t *key, dns_kasp_t *kasp, isc_stdtime_t now) {
+	char keystr[DST_KEY_FORMATSIZE];
+	isc_result_t ret;
+	isc_stdtime_t retire;
+	dst_key_state_t s;
+	bool ksk = false, zsk = false;
+
+	REQUIRE(key != NULL);
+	REQUIRE(key->key != NULL);
+
+	/* This key wants to retire and hide in a corner. */
+	ret = dst_key_gettime(key->key, DST_TIME_INACTIVE, &retire);
+	if (ret != ISC_R_SUCCESS || (retire > now)) {
+		dst_key_settime(key->key, DST_TIME_INACTIVE, now);
+	}
+	dst_key_setstate(key->key, DST_KEY_GOAL, HIDDEN);
+	keymgr_settime_remove(key, kasp);
+
+	/* This key may not have key states set yet. Pretend as if they are
+	 * in the OMNIPRESENT state.
+	 */
+	if (dst_key_getstate(key->key, DST_KEY_DNSKEY, &s) != ISC_R_SUCCESS) {
+		dst_key_setstate(key->key, DST_KEY_DNSKEY, OMNIPRESENT);
+		dst_key_settime(key->key, DST_TIME_DNSKEY, now);
+	}
+
+	ret = dst_key_getbool(key->key, DST_BOOL_KSK, &ksk);
+	if (ret == ISC_R_SUCCESS && ksk) {
+		if (dst_key_getstate(key->key, DST_KEY_KRRSIG, &s) !=
+		    ISC_R_SUCCESS)
+		{
+			dst_key_setstate(key->key, DST_KEY_KRRSIG, OMNIPRESENT);
+			dst_key_settime(key->key, DST_TIME_KRRSIG, now);
+		}
+		if (dst_key_getstate(key->key, DST_KEY_DS, &s) != ISC_R_SUCCESS)
+		{
+			dst_key_setstate(key->key, DST_KEY_DS, OMNIPRESENT);
+			dst_key_settime(key->key, DST_TIME_DS, now);
+		}
+	}
+	ret = dst_key_getbool(key->key, DST_BOOL_ZSK, &zsk);
+	if (ret == ISC_R_SUCCESS && zsk) {
+		if (dst_key_getstate(key->key, DST_KEY_ZRRSIG, &s) !=
+		    ISC_R_SUCCESS)
+		{
+			dst_key_setstate(key->key, DST_KEY_ZRRSIG, OMNIPRESENT);
+			dst_key_settime(key->key, DST_TIME_ZRRSIG, now);
+		}
+	}
+
+	dst_key_format(key->key, keystr, sizeof(keystr));
+	isc_log_write(dns_lctx, DNS_LOGCATEGORY_DNSSEC, DNS_LOGMODULE_DNSSEC,
+		      ISC_LOG_INFO, "keymgr: retire DNSKEY %s (%s)", keystr,
+		      keymgr_keyrole(key->key));
+}
+
+/*
+ * Check if a dnsseckey matches kasp key configuration.  A dnsseckey matches
+ * if it has the same algorithm and size, and if it has the same role as the
+ * kasp key configuration.
+ *
+ */
+static bool
+keymgr_dnsseckey_kaspkey_match(dns_dnsseckey_t *dkey, dns_kasp_key_t *kkey) {
+	dst_key_t *key;
+	isc_result_t ret;
+	bool role = false;
+
+	REQUIRE(dkey != NULL);
+	REQUIRE(kkey != NULL);
+
+	key = dkey->key;
+
+	/* Matching algorithms? */
+	if (dst_key_alg(key) != dns_kasp_key_algorithm(kkey)) {
+		return (false);
+	}
+	/* Matching length? */
+	if (dst_key_size(key) != dns_kasp_key_size(kkey)) {
+		return (false);
+	}
+	/* Matching role? */
+	ret = dst_key_getbool(key, DST_BOOL_KSK, &role);
+	if (ret != ISC_R_SUCCESS || role != dns_kasp_key_ksk(kkey)) {
+		return (false);
+	}
+	ret = dst_key_getbool(key, DST_BOOL_ZSK, &role);
+	if (ret != ISC_R_SUCCESS || role != dns_kasp_key_zsk(kkey)) {
+		return (false);
+	}
+
+	/* Found a match. */
+	return (true);
+}
+
+static bool
+keymgr_keyid_conflict(dst_key_t *newkey, dns_dnsseckeylist_t *keys) {
+	uint16_t id = dst_key_id(newkey);
+	uint32_t rid = dst_key_rid(newkey);
+	uint32_t alg = dst_key_alg(newkey);
+
+	for (dns_dnsseckey_t *dkey = ISC_LIST_HEAD(*keys); dkey != NULL;
+	     dkey = ISC_LIST_NEXT(dkey, link))
+	{
+		if (dst_key_alg(dkey->key) != alg) {
+			continue;
+		}
+		if (dst_key_id(dkey->key) == id ||
+		    dst_key_rid(dkey->key) == id ||
+		    dst_key_id(dkey->key) == rid ||
+		    dst_key_rid(dkey->key) == rid)
+		{
+			return (true);
+		}
+	}
+	return (false);
+}
+
+/*
+ * Create a new key for 'origin' given the kasp key configuration 'kkey'.
+ * This will check for key id collisions with keys in 'keylist'.
+ * The created key will be stored in 'dst_key'.
+ *
+ */
+static isc_result_t
+keymgr_createkey(dns_kasp_key_t *kkey, const dns_name_t *origin,
+		 dns_rdataclass_t rdclass, isc_mem_t *mctx,
+		 dns_dnsseckeylist_t *keylist, dns_dnsseckeylist_t *newkeys,
+		 dst_key_t **dst_key) {
+	bool conflict = false;
+	int keyflags = DNS_KEYOWNER_ZONE;
+	isc_result_t result = ISC_R_SUCCESS;
+	dst_key_t *newkey = NULL;
+
+	do {
+		uint32_t algo = dns_kasp_key_algorithm(kkey);
+		int size = dns_kasp_key_size(kkey);
+
+		if (dns_kasp_key_ksk(kkey)) {
+			keyflags |= DNS_KEYFLAG_KSK;
+		}
+		RETERR(dst_key_generate(origin, algo, size, 0, keyflags,
+					DNS_KEYPROTO_DNSSEC, rdclass, mctx,
+					&newkey, NULL));
+
+		/* Key collision? */
+		conflict = keymgr_keyid_conflict(newkey, keylist);
+		if (!conflict) {
+			conflict = keymgr_keyid_conflict(newkey, newkeys);
+		}
+		if (conflict) {
+			/* Try again. */
+			isc_log_write(dns_lctx, DNS_LOGCATEGORY_DNSSEC,
+				      DNS_LOGMODULE_DNSSEC, ISC_LOG_WARNING,
+				      "keymgr: key collision id %d",
+				      dst_key_id(newkey));
+			dst_key_free(&newkey);
+		}
+	} while (conflict);
+
+	INSIST(!conflict);
+	dst_key_setnum(newkey, DST_NUM_LIFETIME, dns_kasp_key_lifetime(kkey));
+	dst_key_setbool(newkey, DST_BOOL_KSK, dns_kasp_key_ksk(kkey));
+	dst_key_setbool(newkey, DST_BOOL_ZSK, dns_kasp_key_zsk(kkey));
+	*dst_key = newkey;
+	return (ISC_R_SUCCESS);
+
+failure:
+	return (result);
+}
+
+/*
+ * Return the desired state for this record 'type'.  The desired state depends
+ * on whether the key wants to be active, or wants to retire.  This implements
+ * the edges of our state machine:
+ *
+ *            ---->  OMNIPRESENT  ----
+ *            |                      |
+ *            |                     \|/
+ *
+ *        RUMOURED     <---->   UNRETENTIVE
+ *
+ *           /|\                     |
+ *            |                      |
+ *            ----     HIDDEN    <----
+ *
+ * A key that wants to be active eventually wants to have its record types
+ * in the OMNIPRESENT state (that is, all resolvers that know about these
+ * type of records know about these records specifically).
+ *
+ * A key that wants to be retired eventually wants to have its record types
+ * in the HIDDEN state (that is, all resolvers that know about these type
+ * of records specifically don't know about these records).
+ *
+ */
+static dst_key_state_t
+keymgr_desiredstate(dns_dnsseckey_t *key, dst_key_state_t state) {
+	dst_key_state_t goal;
+
+	if (dst_key_getstate(key->key, DST_KEY_GOAL, &goal) != ISC_R_SUCCESS) {
+		/* No goal? No movement. */
+		return (state);
+	}
+
+	if (goal == HIDDEN) {
+		switch (state) {
+		case RUMOURED:
+		case OMNIPRESENT:
+			return (UNRETENTIVE);
+		case HIDDEN:
+		case UNRETENTIVE:
+			return (HIDDEN);
+		default:
+			return (state);
+		}
+	} else if (goal == OMNIPRESENT) {
+		switch (state) {
+		case RUMOURED:
+		case OMNIPRESENT:
+			return (OMNIPRESENT);
+		case HIDDEN:
+		case UNRETENTIVE:
+			return (RUMOURED);
+		default:
+			return (state);
+		}
+	}
+
+	/* Unknown goal. */
+	return (state);
+}
+
+/*
+ * Check if 'key' matches specific 'states'.
+ * A state in 'states' that is NA matches any state.
+ * A state in 'states' that is HIDDEN also matches if the state is not set.
+ * If 'next_state' is set (not NA), we are pretending as if record 'type' of
+ * 'subject' key already transitioned to the 'next state'.
+ *
+ */
+static bool
+keymgr_key_match_state(dst_key_t *key, dst_key_t *subject, int type,
+		       dst_key_state_t next_state,
+		       dst_key_state_t states[NUM_KEYSTATES]) {
+	REQUIRE(key != NULL);
+
+	for (int i = 0; i < NUM_KEYSTATES; i++) {
+		dst_key_state_t state;
+		if (states[i] == NA) {
+			continue;
+		}
+		if (next_state != NA && i == type &&
+		    dst_key_id(key) == dst_key_id(subject))
+		{
+			/* Check next state rather than current state. */
+			state = next_state;
+		} else if (dst_key_getstate(key, i, &state) != ISC_R_SUCCESS) {
+			/* This is fine only if expected state is HIDDEN. */
+			if (states[i] != HIDDEN) {
+				return (false);
+			}
+			continue;
+		}
+		if (state != states[i]) {
+			return (false);
+		}
+	}
+	/* Match. */
+	return (true);
+}
+
+/*
+ * Key d directly depends on k if d is the direct predecessor of k.
+ */
+static bool
+keymgr_direct_dep(dst_key_t *d, dst_key_t *k) {
+	uint32_t s, p;
+
+	if (dst_key_getnum(d, DST_NUM_SUCCESSOR, &s) != ISC_R_SUCCESS) {
+		return (false);
+	}
+	if (dst_key_getnum(k, DST_NUM_PREDECESSOR, &p) != ISC_R_SUCCESS) {
+		return (false);
+	}
+	return (dst_key_id(d) == p && dst_key_id(k) == s);
+}
+
+/*
+ * Determine which key (if any) has a dependency on k.
+ */
+static bool
+keymgr_dep(dst_key_t *k, dns_dnsseckeylist_t *keyring, uint32_t *dep) {
+	for (dns_dnsseckey_t *d = ISC_LIST_HEAD(*keyring); d != NULL;
+	     d = ISC_LIST_NEXT(d, link))
+	{
+		/*
+		 * Check if k is a direct successor of d, e.g. d depends on k.
+		 */
+		if (keymgr_direct_dep(d->key, k)) {
+			if (dep != NULL) {
+				*dep = dst_key_id(d->key);
+			}
+			return (true);
+		}
+	}
+	return (false);
+}
+
+/*
+ * Check if a 'z' is a successor of 'x'.
+ * This implements Equation(2) of "Flexible and Robust Key Rollover".
+ */
+static bool
+keymgr_key_is_successor(dst_key_t *x, dst_key_t *z, dst_key_t *key, int type,
+			dst_key_state_t next_state,
+			dns_dnsseckeylist_t *keyring) {
+	uint32_t dep_x;
+	uint32_t dep_z;
+
+	/*
+	 * The successor relation requires that the predecessor key must not
+	 * have any other keys relying on it. In other words, there must be
+	 * nothing depending on x.
+	 */
+	if (keymgr_dep(x, keyring, &dep_x)) {
+		return (false);
+	}
+
+	/*
+	 * If there is no keys relying on key z, then z is not a successor.
+	 */
+	if (!keymgr_dep(z, keyring, &dep_z)) {
+		return (false);
+	}
+
+	/*
+	 * x depends on z, thus key z is a direct successor of key x.
+	 */
+	if (dst_key_id(x) == dep_z) {
+		return (true);
+	}
+
+	/*
+	 * It is possible to roll keys faster than the time required to finish
+	 * the rollover procedure. For example, consider the keys x, y, z.
+	 * Key x is currently published and is going to be replaced by y. The
+	 * DNSKEY for x is removed from the zone and at the same moment the
+	 * DNSKEY for y is introduced. Key y is a direct dependency for key x
+	 * and is therefore the successor of x. However, before the new DNSKEY
+	 * has been propagated, key z will replace key y. The DNSKEY for y is
+	 * removed and moves into the same state as key x. Key y now directly
+	 * depends on key z, and key z will be a new successor key for x.
+	 */
+	dst_key_state_t zst[NUM_KEYSTATES] = { NA, NA, NA, NA };
+	for (int i = 0; i < NUM_KEYSTATES; i++) {
+		dst_key_state_t state;
+		if (dst_key_getstate(z, i, &state) != ISC_R_SUCCESS) {
+			continue;
+		}
+		zst[i] = state;
+	}
+
+	for (dns_dnsseckey_t *y = ISC_LIST_HEAD(*keyring); y != NULL;
+	     y = ISC_LIST_NEXT(y, link))
+	{
+		if (dst_key_id(y->key) == dst_key_id(z)) {
+			continue;
+		}
+
+		if (dst_key_id(y->key) != dep_z) {
+			continue;
+		}
+		/*
+		 * This is another key y, that depends on key z. It may be
+		 * part of the successor relation if the key states match
+		 * those of key z.
+		 */
+
+		if (keymgr_key_match_state(y->key, key, type, next_state, zst))
+		{
+			/*
+			 * If y is a successor of x, then z is also a
+			 * successor of x.
+			 */
+			return (keymgr_key_is_successor(x, y->key, key, type,
+							next_state, keyring));
+		}
+	}
+
+	return (false);
+}
+
+/*
+ * Check if a key exists in 'keyring' that matches 'states'.
+ *
+ * If 'match_algorithms', the key must also match the algorithm of 'key'.
+ * If 'next_state' is not NA, we are actually looking for a key as if
+ *   'key' already transitioned to the next state.
+ * If 'check_successor', we also want to make sure there is a successor
+ *   relationship with the found key that matches 'states2'.
+ */
+static bool
+keymgr_key_exists_with_state(dns_dnsseckeylist_t *keyring, dns_dnsseckey_t *key,
+			     int type, dst_key_state_t next_state,
+			     dst_key_state_t states[NUM_KEYSTATES],
+			     dst_key_state_t states2[NUM_KEYSTATES],
+			     bool check_successor, bool match_algorithms) {
+	for (dns_dnsseckey_t *dkey = ISC_LIST_HEAD(*keyring); dkey != NULL;
+	     dkey = ISC_LIST_NEXT(dkey, link))
+	{
+		if (match_algorithms &&
+		    (dst_key_alg(dkey->key) != dst_key_alg(key->key)))
+		{
+			continue;
+		}
+
+		if (!keymgr_key_match_state(dkey->key, key->key, type,
+					    next_state, states))
+		{
+			continue;
+		}
+
+		/* Found a match. */
+		if (!check_successor) {
+			return (true);
+		}
+
+		/*
+		 * We have to make sure that the key we are checking, also
+		 * has a successor relationship with another key.
+		 */
+		for (dns_dnsseckey_t *skey = ISC_LIST_HEAD(*keyring);
+		     skey != NULL; skey = ISC_LIST_NEXT(skey, link))
+		{
+			if (skey == dkey) {
+				continue;
+			}
+
+			if (!keymgr_key_match_state(skey->key, key->key, type,
+						    next_state, states2))
+			{
+				continue;
+			}
+
+			/*
+			 * Found a possible successor, check.
+			 */
+			if (keymgr_key_is_successor(dkey->key, skey->key,
+						    key->key, type, next_state,
+						    keyring))
+			{
+				return (true);
+			}
+		}
+	}
+	/* No match. */
+	return (false);
+}
+
+/*
+ * Check if a key has a successor.
+ */
+static bool
+keymgr_key_has_successor(dns_dnsseckey_t *predecessor,
+			 dns_dnsseckeylist_t *keyring) {
+	for (dns_dnsseckey_t *successor = ISC_LIST_HEAD(*keyring);
+	     successor != NULL; successor = ISC_LIST_NEXT(successor, link))
+	{
+		if (keymgr_direct_dep(predecessor->key, successor->key)) {
+			return (true);
+		}
+	}
+	return (false);
+}
+
+/*
+ * Check if all keys have their DS hidden.  If not, then there must be at
+ * least one key with an OMNIPRESENT DNSKEY.
+ *
+ * If 'next_state' is not NA, we are actually looking for a key as if
+ *   'key' already transitioned to the next state.
+ * If 'match_algorithms', only consider keys with same algorithm of 'key'.
+ *
+ */
+static bool
+keymgr_ds_hidden_or_chained(dns_dnsseckeylist_t *keyring, dns_dnsseckey_t *key,
+			    int type, dst_key_state_t next_state,
+			    bool match_algorithms, bool must_be_hidden) {
+	/* (3e) */
+	dst_key_state_t dnskey_chained[NUM_KEYSTATES] = { OMNIPRESENT, NA,
+							  OMNIPRESENT, NA };
+	dst_key_state_t ds_hidden[NUM_KEYSTATES] = { NA, NA, NA, HIDDEN };
+	/* successor n/a */
+	dst_key_state_t na[NUM_KEYSTATES] = { NA, NA, NA, NA };
+
+	for (dns_dnsseckey_t *dkey = ISC_LIST_HEAD(*keyring); dkey != NULL;
+	     dkey = ISC_LIST_NEXT(dkey, link))
+	{
+		if (match_algorithms &&
+		    (dst_key_alg(dkey->key) != dst_key_alg(key->key)))
+		{
+			continue;
+		}
+
+		if (keymgr_key_match_state(dkey->key, key->key, type,
+					   next_state, ds_hidden))
+		{
+			/* This key has its DS hidden. */
+			continue;
+		}
+
+		if (must_be_hidden) {
+			return (false);
+		}
+
+		/*
+		 * This key does not have its DS hidden. There must be at
+		 * least one key with the same algorithm that provides a
+		 * chain of trust (can be this key).
+		 */
+		if (keymgr_key_match_state(dkey->key, key->key, type,
+					   next_state, dnskey_chained))
+		{
+			/* This DNSKEY and KRRSIG are OMNIPRESENT. */
+			continue;
+		}
+
+		/*
+		 * Perhaps another key provides a chain of trust.
+		 */
+		dnskey_chained[DST_KEY_DS] = OMNIPRESENT;
+		if (!keymgr_key_exists_with_state(keyring, key, type,
+						  next_state, dnskey_chained,
+						  na, false, match_algorithms))
+		{
+			/* There is no chain of trust. */
+			return (false);
+		}
+	}
+	/* All good. */
+	return (true);
+}
+
+/*
+ * Check if all keys have their DNSKEY hidden.  If not, then there must be at
+ * least one key with an OMNIPRESENT ZRRSIG.
+ *
+ * If 'next_state' is not NA, we are actually looking for a key as if
+ *   'key' already transitioned to the next state.
+ * If 'match_algorithms', only consider keys with same algorithm of 'key'.
+ *
+ */
+static bool
+keymgr_dnskey_hidden_or_chained(dns_dnsseckeylist_t *keyring,
+				dns_dnsseckey_t *key, int type,
+				dst_key_state_t next_state,
+				bool match_algorithms) {
+	/* (3i) */
+	dst_key_state_t rrsig_chained[NUM_KEYSTATES] = { OMNIPRESENT,
+							 OMNIPRESENT, NA, NA };
+	dst_key_state_t dnskey_hidden[NUM_KEYSTATES] = { HIDDEN, NA, NA, NA };
+	/* successor n/a */
+	dst_key_state_t na[NUM_KEYSTATES] = { NA, NA, NA, NA };
+
+	for (dns_dnsseckey_t *dkey = ISC_LIST_HEAD(*keyring); dkey != NULL;
+	     dkey = ISC_LIST_NEXT(dkey, link))
+	{
+		if (match_algorithms &&
+		    (dst_key_alg(dkey->key) != dst_key_alg(key->key)))
+		{
+			continue;
+		}
+
+		if (keymgr_key_match_state(dkey->key, key->key, type,
+					   next_state, dnskey_hidden))
+		{
+			/* This key has its DNSKEY hidden. */
+			continue;
+		}
+
+		/*
+		 * This key does not have its DNSKEY hidden. There must be at
+		 * least one key with the same algorithm that has its RRSIG
+		 * records OMNIPRESENT.
+		 */
+		(void)dst_key_getstate(dkey->key, DST_KEY_DNSKEY,
+				       &rrsig_chained[DST_KEY_DNSKEY]);
+		if (!keymgr_key_exists_with_state(keyring, key, type,
+						  next_state, rrsig_chained, na,
+						  false, match_algorithms))
+		{
+			/* There is no chain of trust. */
+			return (false);
+		}
+	}
+	/* All good. */
+	return (true);
+}
+
+/*
+ * Check for existence of DS.
+ *
+ */
+static bool
+keymgr_have_ds(dns_dnsseckeylist_t *keyring, dns_dnsseckey_t *key, int type,
+	       dst_key_state_t next_state, bool secure_to_insecure) {
+	/* (3a) */
+	dst_key_state_t states[2][NUM_KEYSTATES] = {
+		/* DNSKEY, ZRRSIG, KRRSIG, DS */
+		{ NA, NA, NA, OMNIPRESENT }, /* DS present */
+		{ NA, NA, NA, RUMOURED }     /* DS introducing */
+	};
+	/* successor n/a */
+	dst_key_state_t na[NUM_KEYSTATES] = { NA, NA, NA, NA };
+
+	/*
+	 * Equation (3a):
+	 * There is a key with the DS in either RUMOURD or OMNIPRESENT state.
+	 */
+	return (keymgr_key_exists_with_state(keyring, key, type, next_state,
+					     states[0], na, false, false) ||
+		keymgr_key_exists_with_state(keyring, key, type, next_state,
+					     states[1], na, false, false) ||
+		(secure_to_insecure &&
+		 keymgr_key_exists_with_state(keyring, key, type, next_state,
+					      na, na, false, false)));
+}
+
+/*
+ * Check for existence of DNSKEY, or at least a good DNSKEY state.
+ * See equations what are good DNSKEY states.
+ *
+ */
+static bool
+keymgr_have_dnskey(dns_dnsseckeylist_t *keyring, dns_dnsseckey_t *key, int type,
+		   dst_key_state_t next_state) {
+	dst_key_state_t states[9][NUM_KEYSTATES] = {
+		/* DNSKEY,     ZRRSIG, KRRSIG,      DS */
+		{ OMNIPRESENT, NA, OMNIPRESENT, OMNIPRESENT }, /* (3b) */
+
+		{ OMNIPRESENT, NA, OMNIPRESENT, UNRETENTIVE }, /* (3c)p */
+		{ OMNIPRESENT, NA, OMNIPRESENT, RUMOURED },    /* (3c)s */
+
+		{ UNRETENTIVE, NA, UNRETENTIVE, OMNIPRESENT }, /* (3d)p */
+		{ OMNIPRESENT, NA, UNRETENTIVE, OMNIPRESENT }, /* (3d)p */
+		{ UNRETENTIVE, NA, OMNIPRESENT, OMNIPRESENT }, /* (3d)p */
+		{ RUMOURED, NA, RUMOURED, OMNIPRESENT },       /* (3d)s */
+		{ OMNIPRESENT, NA, RUMOURED, OMNIPRESENT },    /* (3d)s */
+		{ RUMOURED, NA, OMNIPRESENT, OMNIPRESENT },    /* (3d)s */
+	};
+	/* successor n/a */
+	dst_key_state_t na[NUM_KEYSTATES] = { NA, NA, NA, NA };
+
+	return (
+		/*
+		 * Equation (3b):
+		 * There is a key with the same algorithm with its DNSKEY,
+		 * KRRSIG and DS records in OMNIPRESENT state.
+		 */
+		keymgr_key_exists_with_state(keyring, key, type, next_state,
+					     states[0], na, false, true) ||
+		/*
+		 * Equation (3c):
+		 * There are two or more keys with an OMNIPRESENT DNSKEY and
+		 * the DS records get swapped.  These keys must be in a
+		 * successor relation.
+		 */
+		keymgr_key_exists_with_state(keyring, key, type, next_state,
+					     states[1], states[2], true,
+					     true) ||
+		/*
+		 * Equation (3d):
+		 * There are two or more keys with an OMNIPRESENT DS and
+		 * the DNSKEY records and its KRRSIG records get swapped.
+		 * These keys must be in a successor relation.  Since the
+		 * state for DNSKEY and KRRSIG move independently, we have
+		 * to check all combinations for DNSKEY and KRRSIG in
+		 * OMNIPRESENT/UNRETENTIVE state for the predecessor, and
+		 * OMNIPRESENT/RUMOURED state for the successor.
+		 */
+		keymgr_key_exists_with_state(keyring, key, type, next_state,
+					     states[3], states[6], true,
+					     true) ||
+		keymgr_key_exists_with_state(keyring, key, type, next_state,
+					     states[3], states[7], true,
+					     true) ||
+		keymgr_key_exists_with_state(keyring, key, type, next_state,
+					     states[3], states[8], true,
+					     true) ||
+		keymgr_key_exists_with_state(keyring, key, type, next_state,
+					     states[4], states[6], true,
+					     true) ||
+		keymgr_key_exists_with_state(keyring, key, type, next_state,
+					     states[4], states[7], true,
+					     true) ||
+		keymgr_key_exists_with_state(keyring, key, type, next_state,
+					     states[4], states[8], true,
+					     true) ||
+		keymgr_key_exists_with_state(keyring, key, type, next_state,
+					     states[5], states[6], true,
+					     true) ||
+		keymgr_key_exists_with_state(keyring, key, type, next_state,
+					     states[5], states[7], true,
+					     true) ||
+		keymgr_key_exists_with_state(keyring, key, type, next_state,
+					     states[5], states[8], true,
+					     true) ||
+		/*
+		 * Equation (3e):
+		 * The key may be in any state as long as all keys have their
+		 * DS HIDDEN, or when their DS is not HIDDEN, there must be a
+		 * key with its DS in the same state and its DNSKEY omnipresent.
+		 * In other words, if a DS record for the same algorithm is
+		 * is still available to some validators, there must be a
+		 * chain of trust for those validators.
+		 */
+		keymgr_ds_hidden_or_chained(keyring, key, type, next_state,
+					    true, false));
+}
+
+/*
+ * Check for existence of RRSIG (zsk), or a good RRSIG state.
+ * See equations what are good RRSIG states.
+ *
+ */
+static bool
+keymgr_have_rrsig(dns_dnsseckeylist_t *keyring, dns_dnsseckey_t *key, int type,
+		  dst_key_state_t next_state) {
+	dst_key_state_t states[11][NUM_KEYSTATES] = {
+		/* DNSKEY,     ZRRSIG,      KRRSIG, DS */
+		{ OMNIPRESENT, OMNIPRESENT, NA, NA }, /* (3f) */
+		{ UNRETENTIVE, OMNIPRESENT, NA, NA }, /* (3g)p */
+		{ RUMOURED, OMNIPRESENT, NA, NA },    /* (3g)s */
+		{ OMNIPRESENT, UNRETENTIVE, NA, NA }, /* (3h)p */
+		{ OMNIPRESENT, RUMOURED, NA, NA },    /* (3h)s */
+	};
+	/* successor n/a */
+	dst_key_state_t na[NUM_KEYSTATES] = { NA, NA, NA, NA };
+
+	return (
+		/*
+		 * If all DS records are hidden than this rule can be ignored.
+		 */
+		keymgr_ds_hidden_or_chained(keyring, key, type, next_state,
+					    true, true) ||
+		/*
+		 * Equation (3f):
+		 * There is a key with the same algorithm with its DNSKEY and
+		 * ZRRSIG records in OMNIPRESENT state.
+		 */
+		keymgr_key_exists_with_state(keyring, key, type, next_state,
+					     states[0], na, false, true) ||
+		/*
+		 * Equation (3g):
+		 * There are two or more keys with OMNIPRESENT ZRRSIG
+		 * records and the DNSKEY records get swapped.  These keys
+		 * must be in a successor relation.
+		 */
+		keymgr_key_exists_with_state(keyring, key, type, next_state,
+					     states[1], states[2], true,
+					     true) ||
+		/*
+		 * Equation (3h):
+		 * There are two or more keys with an OMNIPRESENT DNSKEY
+		 * and the ZRRSIG records get swapped.  These keys must be in
+		 * a successor relation.
+		 */
+		keymgr_key_exists_with_state(keyring, key, type, next_state,
+					     states[3], states[4], true,
+					     true) ||
+		/*
+		 * Equation (3i):
+		 * If no DNSKEYs are published, the state of the signatures is
+		 * irrelevant.  In case a DNSKEY is published however, there
+		 * must be a path that can be validated from there.
+		 */
+		keymgr_dnskey_hidden_or_chained(keyring, key, type, next_state,
+						true));
+}
+
+/*
+ * Check if a transition in the state machine is allowed by the policy.
+ * This means when we do rollovers, we want to follow the rules of the
+ * 1. Pre-publish rollover method (in case of a ZSK)
+ *    - First introduce the DNSKEY record.
+ *    - Only if the DNSKEY record is OMNIPRESENT, introduce ZRRSIG records.
+ *
+ * 2. Double-KSK rollover method (in case of a KSK)
+ *    - First introduce the DNSKEY record, as well as the KRRSIG records.
+ *    - Only if the DNSKEY record is OMNIPRESENT, suggest to introduce the DS.
+ */
+static bool
+keymgr_policy_approval(dns_dnsseckeylist_t *keyring, dns_dnsseckey_t *key,
+		       int type, dst_key_state_t next) {
+	dst_key_state_t dnskeystate = HIDDEN;
+	dst_key_state_t ksk_present[NUM_KEYSTATES] = { OMNIPRESENT, NA,
+						       OMNIPRESENT,
+						       OMNIPRESENT };
+	dst_key_state_t ds_rumoured[NUM_KEYSTATES] = { OMNIPRESENT, NA,
+						       OMNIPRESENT, RUMOURED };
+	dst_key_state_t ds_retired[NUM_KEYSTATES] = { OMNIPRESENT, NA,
+						      OMNIPRESENT,
+						      UNRETENTIVE };
+	dst_key_state_t ksk_rumoured[NUM_KEYSTATES] = { RUMOURED, NA, NA,
+							OMNIPRESENT };
+	dst_key_state_t ksk_retired[NUM_KEYSTATES] = { UNRETENTIVE, NA, NA,
+						       OMNIPRESENT };
+	/* successor n/a */
+	dst_key_state_t na[NUM_KEYSTATES] = { NA, NA, NA, NA };
+
+	if (next != RUMOURED) {
+		/*
+		 * Local policy only adds an extra barrier on transitions to
+		 * the RUMOURED state.
+		 */
+		return (true);
+	}
+
+	switch (type) {
+	case DST_KEY_DNSKEY:
+		/* No restrictions. */
+		return (true);
+	case DST_KEY_ZRRSIG:
+		/* Make sure the DNSKEY record is OMNIPRESENT. */
+		(void)dst_key_getstate(key->key, DST_KEY_DNSKEY, &dnskeystate);
+		if (dnskeystate == OMNIPRESENT) {
+			return (true);
+		}
+		/*
+		 * Or are we introducing a new key for this algorithm? Because
+		 * in that case allow publishing the RRSIG records before the
+		 * DNSKEY.
+		 */
+		return (!(keymgr_key_exists_with_state(keyring, key, type, next,
+						       ksk_present, na, false,
+						       true) ||
+			  keymgr_key_exists_with_state(keyring, key, type, next,
+						       ds_retired, ds_rumoured,
+						       true, true) ||
+			  keymgr_key_exists_with_state(
+				  keyring, key, type, next, ksk_retired,
+				  ksk_rumoured, true, true)));
+	case DST_KEY_KRRSIG:
+		/* Only introduce if the DNSKEY is also introduced. */
+		(void)dst_key_getstate(key->key, DST_KEY_DNSKEY, &dnskeystate);
+		return (dnskeystate != HIDDEN);
+	case DST_KEY_DS:
+		/* Make sure the DNSKEY record is OMNIPRESENT. */
+		(void)dst_key_getstate(key->key, DST_KEY_DNSKEY, &dnskeystate);
+		return (dnskeystate == OMNIPRESENT);
+	default:
+		return (false);
+	}
+}
+
+/*
+ * Check if a transition in the state machine is DNSSEC safe.
+ * This implements Equation(1) of "Flexible and Robust Key Rollover".
+ *
+ */
+static bool
+keymgr_transition_allowed(dns_dnsseckeylist_t *keyring, dns_dnsseckey_t *key,
+			  int type, dst_key_state_t next_state,
+			  bool secure_to_insecure) {
+	/* Debug logging. */
+	if (isc_log_wouldlog(dns_lctx, ISC_LOG_DEBUG(1))) {
+		bool rule1a, rule1b, rule2a, rule2b, rule3a, rule3b;
+		char keystr[DST_KEY_FORMATSIZE];
+		dst_key_format(key->key, keystr, sizeof(keystr));
+		rule1a = keymgr_have_ds(keyring, key, type, NA,
+					secure_to_insecure);
+		rule1b = keymgr_have_ds(keyring, key, type, next_state,
+					secure_to_insecure);
+		rule2a = keymgr_have_dnskey(keyring, key, type, NA);
+		rule2b = keymgr_have_dnskey(keyring, key, type, next_state);
+		rule3a = keymgr_have_rrsig(keyring, key, type, NA);
+		rule3b = keymgr_have_rrsig(keyring, key, type, next_state);
+		isc_log_write(
+			dns_lctx, DNS_LOGCATEGORY_DNSSEC, DNS_LOGMODULE_DNSSEC,
+			ISC_LOG_DEBUG(1),
+			"keymgr: dnssec evaluation of %s %s record %s: "
+			"rule1=(~%s or %s) rule2=(~%s or %s) "
+			"rule3=(~%s or %s)",
+			keymgr_keyrole(key->key), keystr, keystatetags[type],
+			rule1a ? "true" : "false", rule1b ? "true" : "false",
+			rule2a ? "true" : "false", rule2b ? "true" : "false",
+			rule3a ? "true" : "false", rule3b ? "true" : "false");
+	}
+
+	return (
+		/*
+		 * Rule 1: There must be a DS at all times.
+		 * First check the current situation: if the rule check fails,
+		 * we allow the transition to attempt to move us out of the
+		 * invalid state.  If the rule check passes, also check if
+		 * the next state is also still a valid situation.
+		 */
+		(!keymgr_have_ds(keyring, key, type, NA, secure_to_insecure) ||
+		 keymgr_have_ds(keyring, key, type, next_state,
+				secure_to_insecure)) &&
+		/*
+		 * Rule 2: There must be a DNSKEY at all times.  Again, first
+		 * check the current situation, then assess the next state.
+		 */
+		(!keymgr_have_dnskey(keyring, key, type, NA) ||
+		 keymgr_have_dnskey(keyring, key, type, next_state)) &&
+		/*
+		 * Rule 3: There must be RRSIG records at all times. Again,
+		 * first check the current situation, then assess the next
+		 * state.
+		 */
+		(!keymgr_have_rrsig(keyring, key, type, NA) ||
+		 keymgr_have_rrsig(keyring, key, type, next_state)));
+}
+
+/*
+ * Calculate the time when it is safe to do the next transition.
+ *
+ */
+static void
+keymgr_transition_time(dns_dnsseckey_t *key, int type,
+		       dst_key_state_t next_state, dns_kasp_t *kasp,
+		       isc_stdtime_t now, isc_stdtime_t *when) {
+	isc_result_t ret;
+	isc_stdtime_t lastchange, dstime, nexttime = now;
+	dns_ttl_t ttlsig = dns_kasp_zonemaxttl(kasp, true);
+
+	/*
+	 * No need to wait if we move things into an uncertain state.
+	 */
+	if (next_state == RUMOURED || next_state == UNRETENTIVE) {
+		*when = now;
+		return;
+	}
+
+	ret = dst_key_gettime(key->key, keystatetimes[type], &lastchange);
+	if (ret != ISC_R_SUCCESS) {
+		/* No last change, for safety purposes let's set it to now. */
+		dst_key_settime(key->key, keystatetimes[type], now);
+		lastchange = now;
+	}
+
+	switch (type) {
+	case DST_KEY_DNSKEY:
+	case DST_KEY_KRRSIG:
+		switch (next_state) {
+		case OMNIPRESENT:
+			/*
+			 * RFC 7583: The publication interval (Ipub) is the
+			 * amount of time that must elapse after the
+			 * publication of a DNSKEY (plus RRSIG (KSK)) before
+			 * it can be assumed that any resolvers that have the
+			 * relevant RRset cached have a copy of the new
+			 * information.  This is the sum of the propagation
+			 * delay (Dprp) and the DNSKEY TTL (TTLkey).  This
+			 * translates to zone-propagation-delay + dnskey-ttl.
+			 * We will also add the publish-safety interval.
+			 */
+			nexttime = lastchange + dst_key_getttl(key->key) +
+				   dns_kasp_zonepropagationdelay(kasp) +
+				   dns_kasp_publishsafety(kasp);
+			break;
+		case HIDDEN:
+			/*
+			 * Same as OMNIPRESENT but without the publish-safety
+			 * interval.
+			 */
+			nexttime = lastchange + dst_key_getttl(key->key) +
+				   dns_kasp_zonepropagationdelay(kasp);
+			break;
+		default:
+			nexttime = now;
+			break;
+		}
+		break;
+	case DST_KEY_ZRRSIG:
+		switch (next_state) {
+		case OMNIPRESENT:
+		case HIDDEN:
+			/*
+			 * RFC 7583: The retire interval (Iret) is the amount
+			 * of time that must elapse after a DNSKEY or
+			 * associated data enters the retire state for any
+			 * dependent information (RRSIG ZSK) to be purged from
+			 * validating resolver caches.  This is defined as:
+			 *
+			 *     Iret = Dsgn + Dprp + TTLsig
+			 *
+			 * Where Dsgn is the Dsgn is the delay needed to
+			 * ensure that all existing RRsets have been re-signed
+			 * with the new key, Dprp is the propagation delay and
+			 * TTLsig is the maximum TTL of all zone RRSIG
+			 * records.  This translates to:
+			 *
+			 *     Dsgn + zone-propagation-delay + max-zone-ttl.
+			 *
+			 * We will also add the retire-safety interval.
+			 */
+			nexttime = lastchange + ttlsig +
+				   dns_kasp_zonepropagationdelay(kasp) +
+				   dns_kasp_retiresafety(kasp);
+			/*
+			 * Only add the sign delay Dsgn if there is an actual
+			 * predecessor or successor key.
+			 */
+			uint32_t tag;
+			ret = dst_key_getnum(key->key, DST_NUM_PREDECESSOR,
+					     &tag);
+			if (ret != ISC_R_SUCCESS) {
+				ret = dst_key_getnum(key->key,
+						     DST_NUM_SUCCESSOR, &tag);
+			}
+			if (ret == ISC_R_SUCCESS) {
+				nexttime += dns_kasp_signdelay(kasp);
+			}
+			break;
+		default:
+			nexttime = now;
+			break;
+		}
+		break;
+	case DST_KEY_DS:
+		switch (next_state) {
+		/*
+		 * RFC 7583: The successor DS record is published in
+		 * the parent zone and after the registration delay
+		 * (Dreg), the time taken after the DS record has been
+		 * submitted to the parent zone manager for it to be
+		 * placed in the zone.  Key N (the predecessor) must
+		 * remain in the zone until any caches that contain a
+		 * copy of the DS RRset have a copy containing the new
+		 * DS record. This interval is the retire interval
+		 * (Iret), given by:
+		 *
+		 *      Iret = DprpP + TTLds
+		 *
+		 * This translates to:
+		 *
+		 *      parent-propagation-delay + parent-ds-ttl.
+		 *
+		 * We will also add the retire-safety interval.
+		 */
+		case OMNIPRESENT:
+			/* Make sure DS has been seen in the parent. */
+			ret = dst_key_gettime(key->key, DST_TIME_DSPUBLISH,
+					      &dstime);
+			if (ret != ISC_R_SUCCESS || dstime > now) {
+				/* Not yet, try again in an hour. */
+				nexttime = now + 3600;
+			} else {
+				nexttime =
+					dstime + dns_kasp_dsttl(kasp) +
+					dns_kasp_parentpropagationdelay(kasp) +
+					dns_kasp_retiresafety(kasp);
+			}
+			break;
+		case HIDDEN:
+			/* Make sure DS has been withdrawn from the parent. */
+			ret = dst_key_gettime(key->key, DST_TIME_DSDELETE,
+					      &dstime);
+			if (ret != ISC_R_SUCCESS || dstime > now) {
+				/* Not yet, try again in an hour. */
+				nexttime = now + 3600;
+			} else {
+				nexttime =
+					dstime + dns_kasp_dsttl(kasp) +
+					dns_kasp_parentpropagationdelay(kasp) +
+					dns_kasp_retiresafety(kasp);
+			}
+			break;
+		default:
+			nexttime = now;
+			break;
+		}
+		break;
+	default:
+		UNREACHABLE();
+		break;
+	}
+
+	*when = nexttime;
+}
+
+/*
+ * Update keys.
+ * This implements Algorithm (1) of "Flexible and Robust Key Rollover".
+ *
+ */
+static isc_result_t
+keymgr_update(dns_dnsseckeylist_t *keyring, dns_kasp_t *kasp, isc_stdtime_t now,
+	      isc_stdtime_t *nexttime, bool secure_to_insecure) {
+	bool changed;
+
+	/* Repeat until nothing changed. */
+transition:
+	changed = false;
+
+	/* For all keys in the zone. */
+	for (dns_dnsseckey_t *dkey = ISC_LIST_HEAD(*keyring); dkey != NULL;
+	     dkey = ISC_LIST_NEXT(dkey, link))
+	{
+		char keystr[DST_KEY_FORMATSIZE];
+		dst_key_format(dkey->key, keystr, sizeof(keystr));
+
+		/* For all records related to this key. */
+		for (int i = 0; i < NUM_KEYSTATES; i++) {
+			isc_result_t ret;
+			isc_stdtime_t when;
+			dst_key_state_t state, next_state;
+
+			ret = dst_key_getstate(dkey->key, i, &state);
+			if (ret == ISC_R_NOTFOUND) {
+				/*
+				 * This record type is not applicable for this
+				 * key, continue to the next record type.
+				 */
+				continue;
+			}
+
+			isc_log_write(dns_lctx, DNS_LOGCATEGORY_DNSSEC,
+				      DNS_LOGMODULE_DNSSEC, ISC_LOG_DEBUG(1),
+				      "keymgr: examine %s %s type %s "
+				      "in state %s",
+				      keymgr_keyrole(dkey->key), keystr,
+				      keystatetags[i], keystatestrings[state]);
+
+			/* Get the desired next state. */
+			next_state = keymgr_desiredstate(dkey, state);
+			if (state == next_state) {
+				/*
+				 * This record is in a stable state.
+				 * No change needed, continue with the next
+				 * record type.
+				 */
+				isc_log_write(dns_lctx, DNS_LOGCATEGORY_DNSSEC,
+					      DNS_LOGMODULE_DNSSEC,
+					      ISC_LOG_DEBUG(1),
+					      "keymgr: %s %s type %s in "
+					      "stable state %s",
+					      keymgr_keyrole(dkey->key), keystr,
+					      keystatetags[i],
+					      keystatestrings[state]);
+				continue;
+			}
+
+			isc_log_write(dns_lctx, DNS_LOGCATEGORY_DNSSEC,
+				      DNS_LOGMODULE_DNSSEC, ISC_LOG_DEBUG(1),
+				      "keymgr: can we transition %s %s type %s "
+				      "state %s to state %s?",
+				      keymgr_keyrole(dkey->key), keystr,
+				      keystatetags[i], keystatestrings[state],
+				      keystatestrings[next_state]);
+
+			/* Is the transition allowed according to policy? */
+			if (!keymgr_policy_approval(keyring, dkey, i,
+						    next_state))
+			{
+				/* No, please respect rollover methods. */
+				isc_log_write(
+					dns_lctx, DNS_LOGCATEGORY_DNSSEC,
+					DNS_LOGMODULE_DNSSEC, ISC_LOG_DEBUG(1),
+					"keymgr: policy says no to %s %s type "
+					"%s "
+					"state %s to state %s",
+					keymgr_keyrole(dkey->key), keystr,
+					keystatetags[i], keystatestrings[state],
+					keystatestrings[next_state]);
+
+				continue;
+			}
+
+			/* Is the transition DNSSEC safe? */
+			if (!keymgr_transition_allowed(keyring, dkey, i,
+						       next_state,
+						       secure_to_insecure))
+			{
+				/* No, this would make the zone bogus. */
+				isc_log_write(
+					dns_lctx, DNS_LOGCATEGORY_DNSSEC,
+					DNS_LOGMODULE_DNSSEC, ISC_LOG_DEBUG(1),
+					"keymgr: dnssec says no to %s %s type "
+					"%s "
+					"state %s to state %s",
+					keymgr_keyrole(dkey->key), keystr,
+					keystatetags[i], keystatestrings[state],
+					keystatestrings[next_state]);
+				continue;
+			}
+
+			/* Is it time to make the transition? */
+			when = now;
+			keymgr_transition_time(dkey, i, next_state, kasp, now,
+					       &when);
+			if (when > now) {
+				/* Not yet. */
+				isc_log_write(
+					dns_lctx, DNS_LOGCATEGORY_DNSSEC,
+					DNS_LOGMODULE_DNSSEC, ISC_LOG_DEBUG(1),
+					"keymgr: time says no to %s %s type %s "
+					"state %s to state %s (wait %u "
+					"seconds)",
+					keymgr_keyrole(dkey->key), keystr,
+					keystatetags[i], keystatestrings[state],
+					keystatestrings[next_state],
+					when - now);
+				if (*nexttime == 0 || *nexttime > when) {
+					*nexttime = when;
+				}
+				continue;
+			}
+
+			isc_log_write(dns_lctx, DNS_LOGCATEGORY_DNSSEC,
+				      DNS_LOGMODULE_DNSSEC, ISC_LOG_DEBUG(1),
+				      "keymgr: transition %s %s type %s "
+				      "state %s to state %s!",
+				      keymgr_keyrole(dkey->key), keystr,
+				      keystatetags[i], keystatestrings[state],
+				      keystatestrings[next_state]);
+
+			/* It is safe to make the transition. */
+			dst_key_setstate(dkey->key, i, next_state);
+			dst_key_settime(dkey->key, keystatetimes[i], now);
+			INSIST(dst_key_ismodified(dkey->key));
+			changed = true;
+		}
+	}
+
+	/* We changed something, continue processing. */
+	if (changed) {
+		goto transition;
+	}
+
+	return (ISC_R_SUCCESS);
+}
+
+/*
+ * See if this key needs to be initialized with properties.  A key created
+ * and derived from a dnssec-policy will have the required metadata available,
+ * otherwise these may be missing and need to be initialized.  The key states
+ * will be initialized according to existing timing metadata.
+ *
+ */
+static void
+keymgr_key_init(dns_dnsseckey_t *key, dns_kasp_t *kasp, isc_stdtime_t now,
+		bool csk) {
+	bool ksk, zsk;
+	isc_result_t ret;
+	isc_stdtime_t active = 0, pub = 0, syncpub = 0, retire = 0, remove = 0;
+	dst_key_state_t dnskey_state = HIDDEN;
+	dst_key_state_t ds_state = HIDDEN;
+	dst_key_state_t zrrsig_state = HIDDEN;
+	dst_key_state_t goal_state = HIDDEN;
+
+	REQUIRE(key != NULL);
+	REQUIRE(key->key != NULL);
+
+	/* Initialize role. */
+	ret = dst_key_getbool(key->key, DST_BOOL_KSK, &ksk);
+	if (ret != ISC_R_SUCCESS) {
+		ksk = ((dst_key_flags(key->key) & DNS_KEYFLAG_KSK) != 0);
+		dst_key_setbool(key->key, DST_BOOL_KSK, (ksk || csk));
+	}
+	ret = dst_key_getbool(key->key, DST_BOOL_ZSK, &zsk);
+	if (ret != ISC_R_SUCCESS) {
+		zsk = ((dst_key_flags(key->key) & DNS_KEYFLAG_KSK) == 0);
+		dst_key_setbool(key->key, DST_BOOL_ZSK, (zsk || csk));
+	}
+
+	/* Get time metadata. */
+	ret = dst_key_gettime(key->key, DST_TIME_ACTIVATE, &active);
+	if (active <= now && ret == ISC_R_SUCCESS) {
+		dns_ttl_t ttlsig = dns_kasp_zonemaxttl(kasp, true);
+		ttlsig += dns_kasp_zonepropagationdelay(kasp);
+		if ((active + ttlsig) <= now) {
+			zrrsig_state = OMNIPRESENT;
+		} else {
+			zrrsig_state = RUMOURED;
+		}
+		goal_state = OMNIPRESENT;
+	}
+	ret = dst_key_gettime(key->key, DST_TIME_PUBLISH, &pub);
+	if (pub <= now && ret == ISC_R_SUCCESS) {
+		dns_ttl_t key_ttl = dst_key_getttl(key->key);
+		key_ttl += dns_kasp_zonepropagationdelay(kasp);
+		if ((pub + key_ttl) <= now) {
+			dnskey_state = OMNIPRESENT;
+		} else {
+			dnskey_state = RUMOURED;
+		}
+		goal_state = OMNIPRESENT;
+	}
+	ret = dst_key_gettime(key->key, DST_TIME_SYNCPUBLISH, &syncpub);
+	if (syncpub <= now && ret == ISC_R_SUCCESS) {
+		dns_ttl_t ds_ttl = dns_kasp_dsttl(kasp);
+		ds_ttl += dns_kasp_parentpropagationdelay(kasp);
+		if ((syncpub + ds_ttl) <= now) {
+			ds_state = OMNIPRESENT;
+		} else {
+			ds_state = RUMOURED;
+		}
+		goal_state = OMNIPRESENT;
+	}
+	ret = dst_key_gettime(key->key, DST_TIME_INACTIVE, &retire);
+	if (retire <= now && ret == ISC_R_SUCCESS) {
+		dns_ttl_t ttlsig = dns_kasp_zonemaxttl(kasp, true);
+		ttlsig += dns_kasp_zonepropagationdelay(kasp);
+		if ((retire + ttlsig) <= now) {
+			zrrsig_state = HIDDEN;
+		} else {
+			zrrsig_state = UNRETENTIVE;
+		}
+		ds_state = UNRETENTIVE;
+		goal_state = HIDDEN;
+	}
+	ret = dst_key_gettime(key->key, DST_TIME_DELETE, &remove);
+	if (remove <= now && ret == ISC_R_SUCCESS) {
+		dns_ttl_t key_ttl = dst_key_getttl(key->key);
+		key_ttl += dns_kasp_zonepropagationdelay(kasp);
+		if ((remove + key_ttl) <= now) {
+			dnskey_state = HIDDEN;
+		} else {
+			dnskey_state = UNRETENTIVE;
+		}
+		zrrsig_state = HIDDEN;
+		ds_state = HIDDEN;
+		goal_state = HIDDEN;
+	}
+
+	/* Set goal if not already set. */
+	if (dst_key_getstate(key->key, DST_KEY_GOAL, &goal_state) !=
+	    ISC_R_SUCCESS)
+	{
+		dst_key_setstate(key->key, DST_KEY_GOAL, goal_state);
+	}
+
+	/* Set key states for all keys that do not have them. */
+	INITIALIZE_STATE(key->key, DST_KEY_DNSKEY, DST_TIME_DNSKEY,
+			 dnskey_state, now);
+	if (ksk || csk) {
+		INITIALIZE_STATE(key->key, DST_KEY_KRRSIG, DST_TIME_KRRSIG,
+				 dnskey_state, now);
+		INITIALIZE_STATE(key->key, DST_KEY_DS, DST_TIME_DS, ds_state,
+				 now);
+	}
+	if (zsk || csk) {
+		INITIALIZE_STATE(key->key, DST_KEY_ZRRSIG, DST_TIME_ZRRSIG,
+				 zrrsig_state, now);
+	}
+}
+
+static isc_result_t
+keymgr_key_rollover(dns_kasp_key_t *kaspkey, dns_dnsseckey_t *active_key,
+		    dns_dnsseckeylist_t *keyring, dns_dnsseckeylist_t *newkeys,
+		    const dns_name_t *origin, dns_rdataclass_t rdclass,
+		    dns_kasp_t *kasp, uint32_t lifetime, bool rollover,
+		    isc_stdtime_t now, isc_stdtime_t *nexttime,
+		    isc_mem_t *mctx) {
+	char keystr[DST_KEY_FORMATSIZE];
+	isc_stdtime_t retire = 0, active = 0, prepub = 0;
+	dns_dnsseckey_t *new_key = NULL;
+	dns_dnsseckey_t *candidate = NULL;
+	dst_key_t *dst_key = NULL;
+
+	/* Do we need to create a successor for the active key? */
+	if (active_key != NULL) {
+		if (isc_log_wouldlog(dns_lctx, ISC_LOG_DEBUG(1))) {
+			dst_key_format(active_key->key, keystr, sizeof(keystr));
+			isc_log_write(
+				dns_lctx, DNS_LOGCATEGORY_DNSSEC,
+				DNS_LOGMODULE_DNSSEC, ISC_LOG_DEBUG(1),
+				"keymgr: DNSKEY %s (%s) is active in policy %s",
+				keystr, keymgr_keyrole(active_key->key),
+				dns_kasp_getname(kasp));
+		}
+
+		/*
+		 * Calculate when the successor needs to be published
+		 * in the zone.
+		 */
+		prepub = keymgr_prepublication_time(active_key, kasp, lifetime,
+						    now);
+		if (prepub > now) {
+			if (isc_log_wouldlog(dns_lctx, ISC_LOG_DEBUG(1))) {
+				dst_key_format(active_key->key, keystr,
+					       sizeof(keystr));
+				isc_log_write(
+					dns_lctx, DNS_LOGCATEGORY_DNSSEC,
+					DNS_LOGMODULE_DNSSEC, ISC_LOG_DEBUG(1),
+					"keymgr: new successor needed for "
+					"DNSKEY %s (%s) (policy %s) in %u "
+					"seconds",
+					keystr, keymgr_keyrole(active_key->key),
+					dns_kasp_getname(kasp), (prepub - now));
+			}
+		}
+		if (prepub == 0 || prepub > now) {
+			/* No need to start rollover now. */
+			if (*nexttime == 0 || prepub < *nexttime) {
+				*nexttime = prepub;
+			}
+			return (ISC_R_SUCCESS);
+		}
+
+		if (keymgr_key_has_successor(active_key, keyring)) {
+			/* Key already has successor. */
+			if (isc_log_wouldlog(dns_lctx, ISC_LOG_DEBUG(1))) {
+				dst_key_format(active_key->key, keystr,
+					       sizeof(keystr));
+				isc_log_write(
+					dns_lctx, DNS_LOGCATEGORY_DNSSEC,
+					DNS_LOGMODULE_DNSSEC, ISC_LOG_DEBUG(1),
+					"keymgr: key DNSKEY %s (%s) (policy "
+					"%s) already has successor",
+					keystr, keymgr_keyrole(active_key->key),
+					dns_kasp_getname(kasp));
+			}
+			return (ISC_R_SUCCESS);
+		}
+
+		if (isc_log_wouldlog(dns_lctx, ISC_LOG_DEBUG(1))) {
+			dst_key_format(active_key->key, keystr, sizeof(keystr));
+			isc_log_write(dns_lctx, DNS_LOGCATEGORY_DNSSEC,
+				      DNS_LOGMODULE_DNSSEC, ISC_LOG_DEBUG(1),
+				      "keymgr: need successor for DNSKEY %s "
+				      "(%s) (policy %s)",
+				      keystr, keymgr_keyrole(active_key->key),
+				      dns_kasp_getname(kasp));
+		}
+
+		/*
+		 * If rollover is not allowed, warn.
+		 */
+		if (!rollover) {
+			dst_key_format(active_key->key, keystr, sizeof(keystr));
+			isc_log_write(dns_lctx, DNS_LOGCATEGORY_DNSSEC,
+				      DNS_LOGMODULE_DNSSEC, ISC_LOG_WARNING,
+				      "keymgr: DNSKEY %s (%s) is offline in "
+				      "policy %s, cannot start rollover",
+				      keystr, keymgr_keyrole(active_key->key),
+				      dns_kasp_getname(kasp));
+			return (ISC_R_SUCCESS);
+		}
+	} else if (isc_log_wouldlog(dns_lctx, ISC_LOG_DEBUG(1))) {
+		char namestr[DNS_NAME_FORMATSIZE];
+		dns_name_format(origin, namestr, sizeof(namestr));
+		isc_log_write(dns_lctx, DNS_LOGCATEGORY_DNSSEC,
+			      DNS_LOGMODULE_DNSSEC, ISC_LOG_DEBUG(1),
+			      "keymgr: no active key found for %s (policy %s)",
+			      namestr, dns_kasp_getname(kasp));
+	}
+
+	/* It is time to do key rollover, we need a new key. */
+
+	/*
+	 * Check if there is a key available in pool because keys
+	 * may have been pregenerated with dnssec-keygen.
+	 */
+	for (candidate = ISC_LIST_HEAD(*keyring); candidate != NULL;
+	     candidate = ISC_LIST_NEXT(candidate, link))
+	{
+		if (keymgr_dnsseckey_kaspkey_match(candidate, kaspkey) &&
+		    dst_key_is_unused(candidate->key))
+		{
+			/* Found a candidate in keyring. */
+			break;
+		}
+	}
+
+	if (candidate == NULL) {
+		/* No key available in keyring, create a new one. */
+		bool csk = (dns_kasp_key_ksk(kaspkey) &&
+			    dns_kasp_key_zsk(kaspkey));
+
+		isc_result_t result = keymgr_createkey(kaspkey, origin, rdclass,
+						       mctx, keyring, newkeys,
+						       &dst_key);
+		if (result != ISC_R_SUCCESS) {
+			return (result);
+		}
+		dst_key_setttl(dst_key, dns_kasp_dnskeyttl(kasp));
+		dst_key_settime(dst_key, DST_TIME_CREATED, now);
+		result = dns_dnsseckey_create(mctx, &dst_key, &new_key);
+		if (result != ISC_R_SUCCESS) {
+			return (result);
+		}
+		keymgr_key_init(new_key, kasp, now, csk);
+	} else {
+		new_key = candidate;
+	}
+	dst_key_setnum(new_key->key, DST_NUM_LIFETIME, lifetime);
+
+	/* Got a key. */
+	if (active_key == NULL) {
+		/*
+		 * If there is no active key found yet for this kasp
+		 * key configuration, immediately make this key active.
+		 */
+		dst_key_settime(new_key->key, DST_TIME_PUBLISH, now);
+		dst_key_settime(new_key->key, DST_TIME_ACTIVATE, now);
+		keymgr_settime_syncpublish(new_key, kasp, true);
+		active = now;
+	} else {
+		/*
+		 * This is a successor.  Mark the relationship.
+		 */
+		isc_stdtime_t created;
+		(void)dst_key_gettime(new_key->key, DST_TIME_CREATED, &created);
+
+		dst_key_setnum(new_key->key, DST_NUM_PREDECESSOR,
+			       dst_key_id(active_key->key));
+		dst_key_setnum(active_key->key, DST_NUM_SUCCESSOR,
+			       dst_key_id(new_key->key));
+		(void)dst_key_gettime(active_key->key, DST_TIME_INACTIVE,
+				      &retire);
+		active = retire;
+
+		/*
+		 * If prepublication time and/or retire time are
+		 * in the past (before the new key was created), use
+		 * creation time as published and active time,
+		 * effectively immediately making the key active.
+		 */
+		if (prepub < created) {
+			active += (created - prepub);
+			prepub = created;
+		}
+		if (active < created) {
+			active = created;
+		}
+		dst_key_settime(new_key->key, DST_TIME_PUBLISH, prepub);
+		dst_key_settime(new_key->key, DST_TIME_ACTIVATE, active);
+		keymgr_settime_syncpublish(new_key, kasp, false);
+
+		/*
+		 * Retire predecessor.
+		 */
+		dst_key_setstate(active_key->key, DST_KEY_GOAL, HIDDEN);
+	}
+
+	/* This key wants to be present. */
+	dst_key_setstate(new_key->key, DST_KEY_GOAL, OMNIPRESENT);
+
+	/* Do we need to set retire time? */
+	if (lifetime > 0) {
+		dst_key_settime(new_key->key, DST_TIME_INACTIVE,
+				(active + lifetime));
+		keymgr_settime_remove(new_key, kasp);
+	}
+
+	/* Append dnsseckey to list of new keys. */
+	dns_dnssec_get_hints(new_key, now);
+	new_key->source = dns_keysource_repository;
+	INSIST(!new_key->legacy);
+	if (candidate == NULL) {
+		ISC_LIST_APPEND(*newkeys, new_key, link);
+	}
+
+	/* Logging. */
+	dst_key_format(new_key->key, keystr, sizeof(keystr));
+	isc_log_write(dns_lctx, DNS_LOGCATEGORY_DNSSEC, DNS_LOGMODULE_DNSSEC,
+		      ISC_LOG_INFO, "keymgr: DNSKEY %s (%s) %s for policy %s",
+		      keystr, keymgr_keyrole(new_key->key),
+		      (candidate != NULL) ? "selected" : "created",
+		      dns_kasp_getname(kasp));
+	return (ISC_R_SUCCESS);
+}
+
+static bool
+keymgr_key_may_be_purged(dst_key_t *key, uint32_t after, isc_stdtime_t now) {
+	bool ksk = false;
+	bool zsk = false;
+	dst_key_state_t hidden[NUM_KEYSTATES] = { HIDDEN, NA, NA, NA };
+	isc_stdtime_t lastchange = 0;
+
+	char keystr[DST_KEY_FORMATSIZE];
+	dst_key_format(key, keystr, sizeof(keystr));
+
+	/* If 'purge-keys' is disabled, always retain keys. */
+	if (after == 0) {
+		return (false);
+	}
+
+	/* Don't purge keys with goal OMNIPRESENT */
+	if (dst_key_goal(key) == OMNIPRESENT) {
+		return (false);
+	}
+
+	/* Don't purge unused keys. */
+	if (dst_key_is_unused(key)) {
+		return (false);
+	}
+
+	/* If this key is completely HIDDEN it may be purged. */
+	(void)dst_key_getbool(key, DST_BOOL_KSK, &ksk);
+	(void)dst_key_getbool(key, DST_BOOL_ZSK, &zsk);
+	if (ksk) {
+		hidden[DST_KEY_KRRSIG] = HIDDEN;
+		hidden[DST_KEY_DS] = HIDDEN;
+	}
+	if (zsk) {
+		hidden[DST_KEY_ZRRSIG] = HIDDEN;
+	}
+	if (!keymgr_key_match_state(key, key, 0, NA, hidden)) {
+		return (false);
+	}
+
+	/*
+	 * Check 'purge-keys' interval. If the interval has passed since
+	 * the last key change, it may be purged.
+	 */
+	for (int i = 0; i < NUM_KEYSTATES; i++) {
+		isc_stdtime_t change = 0;
+		(void)dst_key_gettime(key, keystatetimes[i], &change);
+		if (change > lastchange) {
+			lastchange = change;
+		}
+	}
+
+	return ((lastchange + after) < now);
+}
+
+static void
+keymgr_purge_keyfile(dst_key_t *key, const char *dir, int type) {
+	isc_result_t ret;
+	isc_buffer_t fileb;
+	char filename[NAME_MAX];
+
+	/*
+	 * Make the filename.
+	 */
+	isc_buffer_init(&fileb, filename, sizeof(filename));
+	ret = dst_key_buildfilename(key, type, dir, &fileb);
+	if (ret != ISC_R_SUCCESS) {
+		char keystr[DST_KEY_FORMATSIZE];
+		dst_key_format(key, keystr, sizeof(keystr));
+		isc_log_write(dns_lctx, DNS_LOGCATEGORY_DNSSEC,
+			      DNS_LOGMODULE_DNSSEC, ISC_LOG_WARNING,
+			      "keymgr: failed to purge DNSKEY %s (%s): cannot "
+			      "build filename (%s)",
+			      keystr, keymgr_keyrole(key),
+			      isc_result_totext(ret));
+		return;
+	}
+
+	if (unlink(filename) < 0) {
+		char keystr[DST_KEY_FORMATSIZE];
+		dst_key_format(key, keystr, sizeof(keystr));
+		isc_log_write(dns_lctx, DNS_LOGCATEGORY_DNSSEC,
+			      DNS_LOGMODULE_DNSSEC, ISC_LOG_WARNING,
+			      "keymgr: failed to purge DNSKEY %s (%s): unlink "
+			      "'%s' failed",
+			      keystr, keymgr_keyrole(key), filename);
+	}
+}
+
+/*
+ * Examine 'keys' and match 'kasp' policy.
+ *
+ */
+isc_result_t
+dns_keymgr_run(const dns_name_t *origin, dns_rdataclass_t rdclass,
+	       const char *directory, isc_mem_t *mctx,
+	       dns_dnsseckeylist_t *keyring, dns_dnsseckeylist_t *dnskeys,
+	       dns_kasp_t *kasp, isc_stdtime_t now, isc_stdtime_t *nexttime) {
+	isc_result_t result = ISC_R_SUCCESS;
+	dns_dnsseckeylist_t newkeys;
+	dns_kasp_key_t *kkey;
+	dns_dnsseckey_t *newkey = NULL;
+	isc_dir_t dir;
+	bool dir_open = false;
+	bool secure_to_insecure = false;
+	int numkeys = 0;
+	int options = (DST_TYPE_PRIVATE | DST_TYPE_PUBLIC | DST_TYPE_STATE);
+	char keystr[DST_KEY_FORMATSIZE];
+
+	REQUIRE(DNS_KASP_VALID(kasp));
+	REQUIRE(keyring != NULL);
+
+	ISC_LIST_INIT(newkeys);
+
+	isc_dir_init(&dir);
+	if (directory == NULL) {
+		directory = ".";
+	}
+
+	RETERR(isc_dir_open(&dir, directory));
+	dir_open = true;
+
+	*nexttime = 0;
+
+	/* Debug logging: what keys are available in the keyring? */
+	if (isc_log_wouldlog(dns_lctx, ISC_LOG_DEBUG(1))) {
+		if (ISC_LIST_EMPTY(*keyring)) {
+			char namebuf[DNS_NAME_FORMATSIZE];
+			dns_name_format(origin, namebuf, sizeof(namebuf));
+			isc_log_write(dns_lctx, DNS_LOGCATEGORY_DNSSEC,
+				      DNS_LOGMODULE_DNSSEC, ISC_LOG_DEBUG(1),
+				      "keymgr: keyring empty (zone %s policy "
+				      "%s)",
+				      namebuf, dns_kasp_getname(kasp));
+		}
+
+		for (dns_dnsseckey_t *dkey = ISC_LIST_HEAD(*keyring);
+		     dkey != NULL; dkey = ISC_LIST_NEXT(dkey, link))
+		{
+			dst_key_format(dkey->key, keystr, sizeof(keystr));
+			isc_log_write(dns_lctx, DNS_LOGCATEGORY_DNSSEC,
+				      DNS_LOGMODULE_DNSSEC, ISC_LOG_DEBUG(1),
+				      "keymgr: keyring: %s (policy %s)", keystr,
+				      dns_kasp_getname(kasp));
+		}
+		for (dns_dnsseckey_t *dkey = ISC_LIST_HEAD(*dnskeys);
+		     dkey != NULL; dkey = ISC_LIST_NEXT(dkey, link))
+		{
+			dst_key_format(dkey->key, keystr, sizeof(keystr));
+			isc_log_write(dns_lctx, DNS_LOGCATEGORY_DNSSEC,
+				      DNS_LOGMODULE_DNSSEC, ISC_LOG_DEBUG(1),
+				      "keymgr: dnskeys: %s (policy %s)", keystr,
+				      dns_kasp_getname(kasp));
+		}
+	}
+
+	for (dns_dnsseckey_t *dkey = ISC_LIST_HEAD(*dnskeys); dkey != NULL;
+	     dkey = ISC_LIST_NEXT(dkey, link))
+	{
+		numkeys++;
+	}
+
+	/* Do we need to remove keys? */
+	for (dns_dnsseckey_t *dkey = ISC_LIST_HEAD(*keyring); dkey != NULL;
+	     dkey = ISC_LIST_NEXT(dkey, link))
+	{
+		bool found_match = false;
+
+		keymgr_key_init(dkey, kasp, now, (numkeys == 1));
+
+		for (kkey = ISC_LIST_HEAD(dns_kasp_keys(kasp)); kkey != NULL;
+		     kkey = ISC_LIST_NEXT(kkey, link))
+		{
+			if (keymgr_dnsseckey_kaspkey_match(dkey, kkey)) {
+				found_match = true;
+				break;
+			}
+		}
+
+		/* No match, so retire unwanted retire key. */
+		if (!found_match) {
+			keymgr_key_retire(dkey, kasp, now);
+		}
+
+		/* Check purge-keys interval. */
+		if (keymgr_key_may_be_purged(dkey->key,
+					     dns_kasp_purgekeys(kasp), now))
+		{
+			dst_key_format(dkey->key, keystr, sizeof(keystr));
+			isc_log_write(dns_lctx, DNS_LOGCATEGORY_DNSSEC,
+				      DNS_LOGMODULE_DNSSEC, ISC_LOG_INFO,
+				      "keymgr: purge DNSKEY %s (%s) according "
+				      "to policy %s",
+				      keystr, keymgr_keyrole(dkey->key),
+				      dns_kasp_getname(kasp));
+
+			keymgr_purge_keyfile(dkey->key, directory,
+					     DST_TYPE_PUBLIC);
+			keymgr_purge_keyfile(dkey->key, directory,
+					     DST_TYPE_PRIVATE);
+			keymgr_purge_keyfile(dkey->key, directory,
+					     DST_TYPE_STATE);
+
+			dkey->purge = true;
+		}
+	}
+
+	/* Create keys according to the policy, if come in short. */
+	for (kkey = ISC_LIST_HEAD(dns_kasp_keys(kasp)); kkey != NULL;
+	     kkey = ISC_LIST_NEXT(kkey, link))
+	{
+		uint32_t lifetime = dns_kasp_key_lifetime(kkey);
+		dns_dnsseckey_t *active_key = NULL;
+		bool rollover_allowed = true;
+
+		/* Do we have keys available for this kasp key? */
+		for (dns_dnsseckey_t *dkey = ISC_LIST_HEAD(*keyring);
+		     dkey != NULL; dkey = ISC_LIST_NEXT(dkey, link))
+		{
+			if (keymgr_dnsseckey_kaspkey_match(dkey, kkey)) {
+				/* Found a match. */
+				dst_key_format(dkey->key, keystr,
+					       sizeof(keystr));
+				isc_log_write(dns_lctx, DNS_LOGCATEGORY_DNSSEC,
+					      DNS_LOGMODULE_DNSSEC,
+					      ISC_LOG_DEBUG(1),
+					      "keymgr: DNSKEY %s (%s) matches "
+					      "policy %s",
+					      keystr, keymgr_keyrole(dkey->key),
+					      dns_kasp_getname(kasp));
+
+				/* Initialize lifetime if not set. */
+				uint32_t l;
+				if (dst_key_getnum(dkey->key, DST_NUM_LIFETIME,
+						   &l) != ISC_R_SUCCESS)
+				{
+					dst_key_setnum(dkey->key,
+						       DST_NUM_LIFETIME,
+						       lifetime);
+				}
+
+				if (active_key) {
+					/* We already have an active key that
+					 * matches the kasp policy.
+					 */
+					if (!dst_key_is_unused(dkey->key) &&
+					    (dst_key_goal(dkey->key) ==
+					     OMNIPRESENT) &&
+					    !keymgr_dep(dkey->key, keyring,
+							NULL) &&
+					    !keymgr_dep(active_key->key,
+							keyring, NULL))
+					{
+						/*
+						 * Multiple signing keys match
+						 * the kasp key configuration.
+						 * Retire excess keys in use.
+						 */
+						keymgr_key_retire(dkey, kasp,
+								  now);
+					}
+					continue;
+				}
+
+				/*
+				 * Save the matched key only if it is active
+				 * or desires to be active.
+				 */
+				if (dst_key_goal(dkey->key) == OMNIPRESENT ||
+				    dst_key_is_active(dkey->key, now))
+				{
+					active_key = dkey;
+				}
+			}
+		}
+
+		if (active_key == NULL) {
+			/*
+			 * We didn't found an active key, perhaps the .private
+			 * key file is offline. If so, we don't want to create
+			 * a successor key. Check if we have an appropriate
+			 * state file.
+			 */
+			for (dns_dnsseckey_t *dnskey = ISC_LIST_HEAD(*dnskeys);
+			     dnskey != NULL;
+			     dnskey = ISC_LIST_NEXT(dnskey, link))
+			{
+				if (keymgr_dnsseckey_kaspkey_match(dnskey,
+								   kkey))
+				{
+					/* Found a match. */
+					dst_key_format(dnskey->key, keystr,
+						       sizeof(keystr));
+					isc_log_write(
+						dns_lctx,
+						DNS_LOGCATEGORY_DNSSEC,
+						DNS_LOGMODULE_DNSSEC,
+						ISC_LOG_DEBUG(1),
+						"keymgr: DNSKEY %s (%s) "
+						"offline, policy %s",
+						keystr,
+						keymgr_keyrole(dnskey->key),
+						dns_kasp_getname(kasp));
+					rollover_allowed = false;
+					active_key = dnskey;
+					break;
+				}
+			}
+		}
+
+		/* See if this key requires a rollover. */
+		RETERR(keymgr_key_rollover(
+			kkey, active_key, keyring, &newkeys, origin, rdclass,
+			kasp, lifetime, rollover_allowed, now, nexttime, mctx));
+	}
+
+	/* Walked all kasp key configurations.  Append new keys. */
+	if (!ISC_LIST_EMPTY(newkeys)) {
+		ISC_LIST_APPENDLIST(*keyring, newkeys, link);
+	}
+
+	/*
+	 * If the policy has an empty key list, this means the zone is going
+	 * back to unsigned.
+	 */
+	secure_to_insecure = dns_kasp_keylist_empty(kasp);
+
+	/* Read to update key states. */
+	keymgr_update(keyring, kasp, now, nexttime, secure_to_insecure);
+
+	/* Store key states and update hints. */
+	for (dns_dnsseckey_t *dkey = ISC_LIST_HEAD(*keyring); dkey != NULL;
+	     dkey = ISC_LIST_NEXT(dkey, link))
+	{
+		if (dst_key_ismodified(dkey->key) && !dkey->purge) {
+			dns_dnssec_get_hints(dkey, now);
+			RETERR(dst_key_tofile(dkey->key, options, directory));
+			dst_key_setmodified(dkey->key, false);
+		}
+	}
+
+	result = ISC_R_SUCCESS;
+
+failure:
+	if (dir_open) {
+		isc_dir_close(&dir);
+	}
+
+	if (result != ISC_R_SUCCESS) {
+		while ((newkey = ISC_LIST_HEAD(newkeys)) != NULL) {
+			ISC_LIST_UNLINK(newkeys, newkey, link);
+			INSIST(newkey->key != NULL);
+			dst_key_free(&newkey->key);
+			dns_dnsseckey_destroy(mctx, &newkey);
+		}
+	}
+
+	if (isc_log_wouldlog(dns_lctx, ISC_LOG_DEBUG(3))) {
+		char namebuf[DNS_NAME_FORMATSIZE];
+		dns_name_format(origin, namebuf, sizeof(namebuf));
+		isc_log_write(dns_lctx, DNS_LOGCATEGORY_DNSSEC,
+			      DNS_LOGMODULE_DNSSEC, ISC_LOG_DEBUG(3),
+			      "keymgr: %s done", namebuf);
+	}
+	return (result);
+}
+
+static isc_result_t
+keymgr_checkds(dns_kasp_t *kasp, dns_dnsseckeylist_t *keyring,
+	       const char *directory, isc_stdtime_t now, isc_stdtime_t when,
+	       bool dspublish, dns_keytag_t id, unsigned int alg,
+	       bool check_id) {
+	int options = (DST_TYPE_PRIVATE | DST_TYPE_PUBLIC | DST_TYPE_STATE);
+	isc_dir_t dir;
+	isc_result_t result;
+	dns_dnsseckey_t *ksk_key = NULL;
+
+	REQUIRE(DNS_KASP_VALID(kasp));
+	REQUIRE(keyring != NULL);
+
+	for (dns_dnsseckey_t *dkey = ISC_LIST_HEAD(*keyring); dkey != NULL;
+	     dkey = ISC_LIST_NEXT(dkey, link))
+	{
+		isc_result_t ret;
+		bool ksk = false;
+
+		ret = dst_key_getbool(dkey->key, DST_BOOL_KSK, &ksk);
+		if (ret == ISC_R_SUCCESS && ksk) {
+			if (check_id && dst_key_id(dkey->key) != id) {
+				continue;
+			}
+			if (alg > 0 && dst_key_alg(dkey->key) != alg) {
+				continue;
+			}
+
+			if (ksk_key != NULL) {
+				/*
+				 * Only checkds for one key at a time.
+				 */
+				return (DNS_R_TOOMANYKEYS);
+			}
+
+			ksk_key = dkey;
+		}
+	}
+
+	if (ksk_key == NULL) {
+		return (DNS_R_NOKEYMATCH);
+	}
+
+	if (dspublish) {
+		dst_key_state_t s;
+		dst_key_settime(ksk_key->key, DST_TIME_DSPUBLISH, when);
+		result = dst_key_getstate(ksk_key->key, DST_KEY_DS, &s);
+		if (result != ISC_R_SUCCESS || s != RUMOURED) {
+			dst_key_setstate(ksk_key->key, DST_KEY_DS, RUMOURED);
+		}
+	} else {
+		dst_key_state_t s;
+		dst_key_settime(ksk_key->key, DST_TIME_DSDELETE, when);
+		result = dst_key_getstate(ksk_key->key, DST_KEY_DS, &s);
+		if (result != ISC_R_SUCCESS || s != UNRETENTIVE) {
+			dst_key_setstate(ksk_key->key, DST_KEY_DS, UNRETENTIVE);
+		}
+	}
+
+	if (isc_log_wouldlog(dns_lctx, ISC_LOG_NOTICE)) {
+		char keystr[DST_KEY_FORMATSIZE];
+		char timestr[26]; /* Minimal buf as per ctime_r() spec. */
+
+		dst_key_format(ksk_key->key, keystr, sizeof(keystr));
+		isc_stdtime_tostring(when, timestr, sizeof(timestr));
+		isc_log_write(dns_lctx, DNS_LOGCATEGORY_DNSSEC,
+			      DNS_LOGMODULE_DNSSEC, ISC_LOG_NOTICE,
+			      "keymgr: checkds DS for key %s seen %s at %s",
+			      keystr, dspublish ? "published" : "withdrawn",
+			      timestr);
+	}
+
+	/* Store key state and update hints. */
+	isc_dir_init(&dir);
+	if (directory == NULL) {
+		directory = ".";
+	}
+	result = isc_dir_open(&dir, directory);
+	if (result != ISC_R_SUCCESS) {
+		return (result);
+	}
+
+	dns_dnssec_get_hints(ksk_key, now);
+	result = dst_key_tofile(ksk_key->key, options, directory);
+	if (result == ISC_R_SUCCESS) {
+		dst_key_setmodified(ksk_key->key, false);
+	}
+	isc_dir_close(&dir);
+
+	return (result);
+}
+
+isc_result_t
+dns_keymgr_checkds(dns_kasp_t *kasp, dns_dnsseckeylist_t *keyring,
+		   const char *directory, isc_stdtime_t now, isc_stdtime_t when,
+		   bool dspublish) {
+	return (keymgr_checkds(kasp, keyring, directory, now, when, dspublish,
+			       0, 0, false));
+}
+
+isc_result_t
+dns_keymgr_checkds_id(dns_kasp_t *kasp, dns_dnsseckeylist_t *keyring,
+		      const char *directory, isc_stdtime_t now,
+		      isc_stdtime_t when, bool dspublish, dns_keytag_t id,
+		      unsigned int alg) {
+	return (keymgr_checkds(kasp, keyring, directory, now, when, dspublish,
+			       id, alg, true));
+}
+
+static void
+keytime_status(dst_key_t *key, isc_stdtime_t now, isc_buffer_t *buf,
+	       const char *pre, int ks, int kt) {
+	char timestr[26]; /* Minimal buf as per ctime_r() spec. */
+	isc_result_t ret;
+	isc_stdtime_t when = 0;
+	dst_key_state_t state = NA;
+
+	isc_buffer_printf(buf, "%s", pre);
+	(void)dst_key_getstate(key, ks, &state);
+	ret = dst_key_gettime(key, kt, &when);
+	if (state == RUMOURED || state == OMNIPRESENT) {
+		isc_buffer_printf(buf, "yes - since ");
+	} else if (now < when) {
+		isc_buffer_printf(buf, "no  - scheduled ");
+	} else {
+		isc_buffer_printf(buf, "no\n");
+		return;
+	}
+	if (ret == ISC_R_SUCCESS) {
+		isc_stdtime_tostring(when, timestr, sizeof(timestr));
+		isc_buffer_printf(buf, "%s\n", timestr);
+	}
+}
+
+static void
+rollover_status(dns_dnsseckey_t *dkey, dns_kasp_t *kasp, isc_stdtime_t now,
+		isc_buffer_t *buf, bool zsk) {
+	char timestr[26]; /* Minimal buf as per ctime_r() spec. */
+	isc_result_t ret = ISC_R_SUCCESS;
+	isc_stdtime_t active_time = 0;
+	dst_key_state_t state = NA, goal = NA;
+	int rrsig, active, retire;
+	dst_key_t *key = dkey->key;
+
+	if (zsk) {
+		rrsig = DST_KEY_ZRRSIG;
+		active = DST_TIME_ACTIVATE;
+		retire = DST_TIME_INACTIVE;
+	} else {
+		rrsig = DST_KEY_KRRSIG;
+		active = DST_TIME_PUBLISH;
+		retire = DST_TIME_DELETE;
+	}
+
+	isc_buffer_printf(buf, "\n");
+
+	(void)dst_key_getstate(key, DST_KEY_GOAL, &goal);
+	(void)dst_key_getstate(key, rrsig, &state);
+	(void)dst_key_gettime(key, active, &active_time);
+	if (active_time == 0) {
+		// only interested in keys that were once active.
+		return;
+	}
+
+	if (goal == HIDDEN && (state == UNRETENTIVE || state == HIDDEN)) {
+		isc_stdtime_t remove_time = 0;
+		// is the key removed yet?
+		state = NA;
+		(void)dst_key_getstate(key, DST_KEY_DNSKEY, &state);
+		if (state == RUMOURED || state == OMNIPRESENT) {
+			ret = dst_key_gettime(key, DST_TIME_DELETE,
+					      &remove_time);
+			if (ret == ISC_R_SUCCESS) {
+				isc_buffer_printf(buf, "  Key is retired, will "
+						       "be removed on ");
+				isc_stdtime_tostring(remove_time, timestr,
+						     sizeof(timestr));
+				isc_buffer_printf(buf, "%s", timestr);
+			}
+		} else {
+			isc_buffer_printf(
+				buf, "  Key has been removed from the zone");
+		}
+	} else {
+		isc_stdtime_t retire_time = 0;
+		uint32_t lifetime = 0;
+		(void)dst_key_getnum(key, DST_NUM_LIFETIME, &lifetime);
+		ret = dst_key_gettime(key, retire, &retire_time);
+		if (ret == ISC_R_SUCCESS) {
+			if (now < retire_time) {
+				if (goal == OMNIPRESENT) {
+					isc_buffer_printf(buf,
+							  "  Next rollover "
+							  "scheduled on ");
+					retire_time = keymgr_prepublication_time(
+						dkey, kasp, lifetime, now);
+				} else {
+					isc_buffer_printf(
+						buf, "  Key will retire on ");
+				}
+			} else {
+				isc_buffer_printf(buf,
+						  "  Rollover is due since ");
+			}
+			isc_stdtime_tostring(retire_time, timestr,
+					     sizeof(timestr));
+			isc_buffer_printf(buf, "%s", timestr);
+		} else {
+			isc_buffer_printf(buf, "  No rollover scheduled");
+		}
+	}
+	isc_buffer_printf(buf, "\n");
+}
+
+static void
+keystate_status(dst_key_t *key, isc_buffer_t *buf, const char *pre, int ks) {
+	dst_key_state_t state = NA;
+
+	(void)dst_key_getstate(key, ks, &state);
+	switch (state) {
+	case HIDDEN:
+		isc_buffer_printf(buf, "  - %shidden\n", pre);
+		break;
+	case RUMOURED:
+		isc_buffer_printf(buf, "  - %srumoured\n", pre);
+		break;
+	case OMNIPRESENT:
+		isc_buffer_printf(buf, "  - %somnipresent\n", pre);
+		break;
+	case UNRETENTIVE:
+		isc_buffer_printf(buf, "  - %sunretentive\n", pre);
+		break;
+	case NA:
+	default:
+		/* print nothing */
+		break;
+	}
+}
+
+void
+dns_keymgr_status(dns_kasp_t *kasp, dns_dnsseckeylist_t *keyring,
+		  isc_stdtime_t now, char *out, size_t out_len) {
+	isc_buffer_t buf;
+	char timestr[26]; /* Minimal buf as per ctime_r() spec. */
+
+	REQUIRE(DNS_KASP_VALID(kasp));
+	REQUIRE(keyring != NULL);
+	REQUIRE(out != NULL);
+
+	isc_buffer_init(&buf, out, out_len);
+
+	// policy name
+	isc_buffer_printf(&buf, "dnssec-policy: %s\n", dns_kasp_getname(kasp));
+	isc_buffer_printf(&buf, "current time:  ");
+	isc_stdtime_tostring(now, timestr, sizeof(timestr));
+	isc_buffer_printf(&buf, "%s\n", timestr);
+
+	for (dns_dnsseckey_t *dkey = ISC_LIST_HEAD(*keyring); dkey != NULL;
+	     dkey = ISC_LIST_NEXT(dkey, link))
+	{
+		char algstr[DNS_NAME_FORMATSIZE];
+		bool ksk = false, zsk = false;
+		isc_result_t ret;
+
+		if (dst_key_is_unused(dkey->key)) {
+			continue;
+		}
+
+		// key data
+		dns_secalg_format((dns_secalg_t)dst_key_alg(dkey->key), algstr,
+				  sizeof(algstr));
+		isc_buffer_printf(&buf, "\nkey: %d (%s), %s\n",
+				  dst_key_id(dkey->key), algstr,
+				  keymgr_keyrole(dkey->key));
+
+		// publish status
+		keytime_status(dkey->key, now, &buf,
+			       "  published:      ", DST_KEY_DNSKEY,
+			       DST_TIME_PUBLISH);
+
+		// signing status
+		ret = dst_key_getbool(dkey->key, DST_BOOL_KSK, &ksk);
+		if (ret == ISC_R_SUCCESS && ksk) {
+			keytime_status(dkey->key, now, &buf,
+				       "  key signing:    ", DST_KEY_KRRSIG,
+				       DST_TIME_PUBLISH);
+		}
+		ret = dst_key_getbool(dkey->key, DST_BOOL_ZSK, &zsk);
+		if (ret == ISC_R_SUCCESS && zsk) {
+			keytime_status(dkey->key, now, &buf,
+				       "  zone signing:   ", DST_KEY_ZRRSIG,
+				       DST_TIME_ACTIVATE);
+		}
+
+		// rollover status
+		rollover_status(dkey, kasp, now, &buf, zsk);
+
+		// key states
+		keystate_status(dkey->key, &buf,
+				"goal:           ", DST_KEY_GOAL);
+		keystate_status(dkey->key, &buf,
+				"dnskey:         ", DST_KEY_DNSKEY);
+		keystate_status(dkey->key, &buf,
+				"ds:             ", DST_KEY_DS);
+		keystate_status(dkey->key, &buf,
+				"zone rrsig:     ", DST_KEY_ZRRSIG);
+		keystate_status(dkey->key, &buf,
+				"key rrsig:      ", DST_KEY_KRRSIG);
+	}
+}
+
+isc_result_t
+dns_keymgr_rollover(dns_kasp_t *kasp, dns_dnsseckeylist_t *keyring,
+		    const char *directory, isc_stdtime_t now,
+		    isc_stdtime_t when, dns_keytag_t id,
+		    unsigned int algorithm) {
+	int options = (DST_TYPE_PRIVATE | DST_TYPE_PUBLIC | DST_TYPE_STATE);
+	isc_dir_t dir;
+	isc_result_t result;
+	dns_dnsseckey_t *key = NULL;
+	isc_stdtime_t active, retire, prepub;
+
+	REQUIRE(DNS_KASP_VALID(kasp));
+	REQUIRE(keyring != NULL);
+
+	for (dns_dnsseckey_t *dkey = ISC_LIST_HEAD(*keyring); dkey != NULL;
+	     dkey = ISC_LIST_NEXT(dkey, link))
+	{
+		if (dst_key_id(dkey->key) != id) {
+			continue;
+		}
+		if (algorithm > 0 && dst_key_alg(dkey->key) != algorithm) {
+			continue;
+		}
+		if (key != NULL) {
+			/*
+			 * Only rollover for one key at a time.
+			 */
+			return (DNS_R_TOOMANYKEYS);
+		}
+		key = dkey;
+	}
+
+	if (key == NULL) {
+		return (DNS_R_NOKEYMATCH);
+	}
+
+	result = dst_key_gettime(key->key, DST_TIME_ACTIVATE, &active);
+	if (result != ISC_R_SUCCESS || active > now) {
+		return (DNS_R_KEYNOTACTIVE);
+	}
+
+	result = dst_key_gettime(key->key, DST_TIME_INACTIVE, &retire);
+	if (result != ISC_R_SUCCESS) {
+		/**
+		 * Default to as if this key was not scheduled to
+		 * become retired, as if it had unlimited lifetime.
+		 */
+		retire = 0;
+	}
+
+	/**
+	 * Usually when is set to now, which is before the scheduled
+	 * prepublication time, meaning we reduce the lifetime of the
+	 * key. But in some cases, the lifetime can also be extended.
+	 * We accept it, but we can return an error here if that
+	 * turns out to be unintuitive behavior.
+	 */
+	prepub = dst_key_getttl(key->key) + dns_kasp_publishsafety(kasp) +
+		 dns_kasp_zonepropagationdelay(kasp);
+	retire = when + prepub;
+
+	dst_key_settime(key->key, DST_TIME_INACTIVE, retire);
+	dst_key_setnum(key->key, DST_NUM_LIFETIME, (retire - active));
+
+	/* Store key state and update hints. */
+	isc_dir_init(&dir);
+	if (directory == NULL) {
+		directory = ".";
+	}
+	result = isc_dir_open(&dir, directory);
+	if (result != ISC_R_SUCCESS) {
+		return (result);
+	}
+
+	dns_dnssec_get_hints(key, now);
+	result = dst_key_tofile(key->key, options, directory);
+	if (result == ISC_R_SUCCESS) {
+		dst_key_setmodified(key->key, false);
+	}
+	isc_dir_close(&dir);
+
+	return (result);
+}