3911. [func] Implement EDNS EXPIRE option client side. [RT #35925]

CHANGES

+3911.	[func]		Implement EDNS EXPIRE option client side. [RT #35925]
+
 3910.	[bug]		Fix races to free event during shutdown. [RT#36720]
 
 3909.	[bug]		When computing the number of elements required for a

bin/named/config.c

@@ -143,6 +143,7 @@ options {\n\
 	recursion true;\n\
 	provide-ixfr true;\n\
 	request-ixfr true;\n\
+	request-expire true;\n\
 	fetch-glue no;\n\
 	rfc2308-type1 no;\n\
 	additional-from-auth true;\n\

bin/named/server.c

@@ -1177,6 +1177,11 @@ configure_peer(const cfg_obj_t *cpeer, isc_mem_t *mctx, dns_peer_t **peerp) {
 	if (obj != NULL)
 		CHECK(dns_peer_setprovideixfr(peer, cfg_obj_asboolean(obj)));
 
+	obj = NULL;
+	(void)cfg_map_get(cpeer, "request-expire", &obj);
+	if (obj != NULL)
+		CHECK(dns_peer_setrequestexpire(peer, cfg_obj_asboolean(obj)));
+
 	obj = NULL;
 	(void)cfg_map_get(cpeer, "request-ixfr", &obj);
 	if (obj != NULL)

bin/named/zoneconf.c

@@ -1256,6 +1256,11 @@ ns_zone_configure(const cfg_obj_t *config, const cfg_obj_t *vconfig,
 			dns_zone_setoption(zone, DNS_ZONEOPT_IXFRFROMDIFFS,
 					   ixfrdiff);
 
+		obj = NULL;
+		result = ns_config_get(maps, "request-expire", &obj);
+		INSIST(result == ISC_R_SUCCESS);
+		dns_zone_setrequestexpire(zone, cfg_obj_asboolean(obj));
+
 		obj = NULL;
 		result = ns_config_get(maps, "request-ixfr", &obj);
 		INSIST(result == ISC_R_SUCCESS);

bin/tests/system/xfer/clean.sh

@@ -26,6 +26,7 @@ rm -f dig.out.ns5 dig.out.ns6 dig.out.ns7
 rm -f dig.out.soa.ns3
 rm -f axfr.out
 rm -f ns1/slave.db ns2/slave.db
+rm -f ns1/edns-expire.db
 rm -f ns2/example.db ns2/tsigzone.db ns2/example.db.jnl
 rm -f ns3/example.bk ns3/tsigzone.bk ns3/example.bk.jnl
 rm -f ns3/master.bk ns3/master.bk.jnl

bin/tests/system/xfer/ns1/named.conf

@@ -44,3 +44,8 @@ zone "slave" {
 	type master;
 	file "slave.db";
 };
+
+zone "edns-expire" {
+	type master;
+	file "edns-expire.db";
+};

bin/tests/system/xfer/ns6/named.conf

@@ -19,7 +19,7 @@
 include "../../common/rndc.key";
 
 controls {
-        inet 10.53.0.6 port 9953 allow { any; } keys { rndc_key; };
+	inet 10.53.0.6 port 9953 allow { any; } keys { rndc_key; };
 };
 
 options {
@@ -52,3 +52,9 @@ zone "slave" {
 	masters { 10.53.0.1; };
 	file "slave.bk";
 };
+
+zone "edns-expire" {
+	type slave;
+	masters { 10.53.0.1; };
+	file "edns-expire.bk";
+};

bin/tests/system/xfer/ns7/named.conf

@@ -51,3 +51,9 @@ zone "slave" {
 	masters { 10.53.0.1; };
 	file "slave.bk";
 };
+
+zone "edns-expire" {
+        type slave;
+        masters { 10.53.0.6; };
+        file "edns-expire.bk";
+};

bin/tests/system/xfer/setup.sh

@@ -21,6 +21,7 @@ SYSTEMTESTTOP=..
 $SHELL clean.sh
 
 $SHELL ../genzone.sh 1 6 7 >ns1/slave.db
+$SHELL ../genzone.sh 1 6 7 >ns1/edns-expire.db
 $SHELL ../genzone.sh 2 3 >ns2/example.db
 $SHELL ../genzone.sh 2 3 >ns2/tsigzone.db
 $SHELL ../genzone.sh 6 3 >ns6/master.db

bin/tests/system/xfer/tests.sh

@@ -331,5 +331,17 @@ $DIGCMD nil. TXT | grep 'incorrect key AXFR' >/dev/null && {
     status=1
 }
 
+echo "I:check that we ask for and get a EDNS EXPIRE response"
+# force a refresh query
+$RNDC -s 10.53.0.7 -p 9953 -c ../common/rndc.conf refresh edns-expire 2>&1 | sed 's/^/I:ns7 /'
+sleep 10
+
+# there may be multiple log entries so get the last one.
+expire=`awk '/edns-expire\/IN: got EDNS EXPIRE of/ { x=$9 } END { print x }' ns7/named.run`
+test ${expire:-0} -gt 0 -a ${expire:-0} -lt 1814400 || {
+    echo "I:failed (expire=${expire:-0})"
+    status=1
+}
+
 echo "I:exit status: $status"
 exit $status

doc/arm/Bv9ARM-book.xml

@@ -4934,6 +4934,7 @@ badresp:1,adberr:0,findfail:0,valfail:0]
     <optional> use-ixfr <replaceable>yes_or_no</replaceable> ; </optional>
     <optional> provide-ixfr <replaceable>yes_or_no</replaceable>; </optional>
     <optional> request-ixfr <replaceable>yes_or_no</replaceable>; </optional>
+    <optional> request-expire <replaceable>yes_or_no</replaceable>; </optional>
     <optional> treat-cr-as-space <replaceable>yes_or_no</replaceable> ; </optional>
     <optional> min-refresh-time <replaceable>number</replaceable> ; </optional>
     <optional> max-refresh-time <replaceable>number</replaceable> ; </optional>
@@ -6476,6 +6477,17 @@ options {
 	      </listitem>
 	    </varlistentry>
 
+	    <varlistentry>
+	      <term><command>request-expire</command></term>
+	      <listitem>
+		<para>
+		  See the description of
+		  <command>request-expire</command> in
+		  <xref linkend="server_statement_definition_and_usage"/>.
+		</para>
+	      </listitem>
+	    </varlistentry>
+
 	    <varlistentry>
 	      <term><command>treat-cr-as-space</command></term>
 	      <listitem>
@@ -10390,6 +10402,7 @@ rate-limit {
     <optional> bogus <replaceable>yes_or_no</replaceable> ; </optional>
     <optional> provide-ixfr <replaceable>yes_or_no</replaceable> ; </optional>
     <optional> request-ixfr <replaceable>yes_or_no</replaceable> ; </optional>
+    <optional> request-expire <replaceable>yes_or_no</replaceable> ; </optional>
     <optional> request-nsid <replaceable>yes_or_no</replaceable> ; </optional>
     <optional> request-sit <replaceable>yes_or_no</replaceable> ; </optional>
     <optional> edns <replaceable>yes_or_no</replaceable> ; </optional>
@@ -10494,6 +10507,12 @@ rate-limit {
 	    is buggy and crashes or corrupts data when IXFR is used.
 	  </para>
 
+	  <para>
+	    The <command>request-expire</command> clause determines
+	    whether the local server, acting as a slave, will request
+	    the EDNS EXPIRE value.
+	  </para>
+
 	  <para>
 	    The <command>edns</command> clause determines whether
 	    the local server will attempt to use EDNS when communicating

lib/bind9/check.c

@@ -1513,6 +1513,7 @@ check_zoneconf(const cfg_obj_t *zconfig, const cfg_obj_t *voptions,
 	{ "notify-source", MASTERZONE | SLAVEZONE },
 	{ "notify-source-v6", MASTERZONE | SLAVEZONE },
 	{ "pubkey", MASTERZONE | SLAVEZONE | STUBZONE },
+	{ "request-expire", SLAVEZONE | REDIRECTZONE },
 	{ "request-ixfr", SLAVEZONE | REDIRECTZONE },
 	{ "server-addresses", STATICSTUBZONE },
 	{ "server-names", STATICSTUBZONE },
@@ -1534,8 +1535,8 @@ check_zoneconf(const cfg_obj_t *zconfig, const cfg_obj_t *voptions,
 	static optionstable dialups[] = {
 	{ "notify", MASTERZONE | SLAVEZONE | STREDIRECTZONE },
 	{ "notify-passive", SLAVEZONE | STREDIRECTZONE },
-	{ "refresh", SLAVEZONE | STUBZONE | STREDIRECTZONE },
 	{ "passive", SLAVEZONE | STUBZONE | STREDIRECTZONE },
+	{ "refresh", SLAVEZONE | STUBZONE | STREDIRECTZONE },
 	};
 
 	znamestr = cfg_obj_asstring(cfg_tuple_get(zconfig, "name"));

lib/dns/include/dns/peer.h

@@ -75,6 +75,7 @@ struct dns_peer {
 	isc_boolean_t		support_edns;
 	isc_boolean_t		request_nsid;
 	isc_boolean_t		request_sit;
+	isc_boolean_t		request_expire;
 	dns_name_t	       *key;
 	isc_sockaddr_t	       *transfer_source;
 	isc_dscp_t		transfer_dscp;
@@ -166,6 +167,12 @@ dns_peer_setrequestsit(dns_peer_t *peer, isc_boolean_t newval);
 isc_result_t
 dns_peer_getrequestsit(dns_peer_t *peer, isc_boolean_t *retval);
 
+isc_result_t
+dns_peer_setrequestexpire(dns_peer_t *peer, isc_boolean_t newval);
+
+isc_result_t
+dns_peer_getrequestexpire(dns_peer_t *peer, isc_boolean_t *retval);
+
 isc_result_t
 dns_peer_setsupportedns(dns_peer_t *peer, isc_boolean_t newval);
 

lib/dns/include/dns/zone.h

@@ -2184,6 +2184,26 @@ dns_zone_setrefreshkeyinterval(dns_zone_t *zone, isc_uint32_t interval);
  * \li	'zone' to be valid.
  */
 
+isc_boolean_t
+dns_zone_getrequestexpire(dns_zone_t *zone);
+/*%
+ * Returns the true/false value of the request-expire option in the zone.
+ *
+ * Requires:
+ * \li	'zone' to be valid.
+ */
+
+void
+dns_zone_setrequestexpire(dns_zone_t *zone, isc_boolean_t flag);
+/*%
+ * Sets the request-expire option for the zone. Either true or false. The
+ * default value is determined by the setting of this option in the view.
+ *
+ * Requires:
+ * \li	'zone' to be valid.
+ */
+
+
 isc_boolean_t
 dns_zone_getrequestixfr(dns_zone_t *zone);
 /*%

lib/dns/peer.c

@@ -47,6 +47,7 @@
 #define NOTIFY_DSCP_BIT                 10
 #define TRANSFER_DSCP_BIT               11
 #define QUERY_DSCP_BIT                 	12
+#define REQUEST_EXPIRE_BIT              13
 
 static void
 peerlist_delete(dns_peerlist_t **list);
@@ -477,6 +478,32 @@ dns_peer_getrequestsit(dns_peer_t *peer, isc_boolean_t *retval) {
 		return (ISC_R_NOTFOUND);
 }
 
+isc_result_t
+dns_peer_setrequestexpire(dns_peer_t *peer, isc_boolean_t newval) {
+	isc_boolean_t existed;
+
+	REQUIRE(DNS_PEER_VALID(peer));
+
+	existed = DNS_BIT_CHECK(REQUEST_EXPIRE_BIT, &peer->bitflags);
+
+	peer->request_expire = newval;
+	DNS_BIT_SET(REQUEST_EXPIRE_BIT, &peer->bitflags);
+
+	return (existed ? ISC_R_EXISTS : ISC_R_SUCCESS);
+}
+
+isc_result_t
+dns_peer_getrequestexpire(dns_peer_t *peer, isc_boolean_t *retval) {
+	REQUIRE(DNS_PEER_VALID(peer));
+	REQUIRE(retval != NULL);
+
+	if (DNS_BIT_CHECK(REQUEST_EXPIRE_BIT, &peer->bitflags)) {
+		*retval = peer->request_expire;
+		return (ISC_R_SUCCESS);
+	} else
+		return (ISC_R_NOTFOUND);
+}
+
 isc_result_t
 dns_peer_settransfers(dns_peer_t *peer, isc_uint32_t newval) {
 	isc_boolean_t existed;

lib/dns/zone.c

@@ -392,6 +392,11 @@ struct dns_zone {
 	 */
 	isc_boolean_t		requestixfr;
 
+	/*%
+	 * whether EDNS EXPIRE is requested
+	 */
+	isc_boolean_t		requestexpire;
+
 	/*%
 	 * Outstanding forwarded UPDATE requests.
 	 */
@@ -999,6 +1004,8 @@ dns_zone_create(dns_zone_t **zonep, isc_mem_t *mctx) {
 	zone->secure = NULL;
 	zone->sourceserial = 0;
 	zone->sourceserialset = ISC_FALSE;
+	zone->requestixfr = ISC_TRUE;
+	zone->requestexpire = ISC_TRUE;
 
 	zone->magic = ZONE_MAGIC;
 
@@ -10934,6 +10941,90 @@ stub_callback(isc_task_t *task, isc_event_t *event) {
 	return;
 }
 
+/*
+ * Get the EDNS EXPIRE option from the response and if it exists trim
+ * expire to be not more than it.
+ */
+static void
+get_edns_expire(dns_zone_t * zone, dns_message_t *message,
+		isc_uint32_t *expirep)
+{
+	isc_result_t result;
+	isc_uint32_t expire;
+	dns_rdata_t rdata = DNS_RDATA_INIT;
+	isc_buffer_t optbuf;
+	isc_uint16_t optcode;
+	isc_uint16_t optlen;
+
+	REQUIRE(expirep != NULL);
+	REQUIRE(message != NULL);
+
+	if (message->opt == NULL)
+		return;
+
+	result = dns_rdataset_first(message->opt);
+	if (result == ISC_R_SUCCESS) {
+		dns_rdataset_current(message->opt, &rdata);
+		isc_buffer_init(&optbuf, rdata.data, rdata.length);
+		isc_buffer_add(&optbuf, rdata.length);
+		while (isc_buffer_remaininglength(&optbuf) >= 4) {
+			optcode = isc_buffer_getuint16(&optbuf);
+			optlen = isc_buffer_getuint16(&optbuf);
+			/*
+			 * A EDNS EXPIRE response has a length of 4.
+			 */
+			if (optcode != DNS_OPT_EXPIRE || optlen != 4) {
+				isc_buffer_forward(&optbuf, optlen);
+				continue;
+			}
+			expire = isc_buffer_getuint32(&optbuf);
+			dns_zone_log(zone, ISC_LOG_DEBUG(1),
+				     "got EDNS EXPIRE of %u\n", expire);
+			/*
+			 * Trim *expirep?
+			 */
+			if (expire < *expirep)
+				*expirep = expire;
+			break;
+		}
+	}
+}
+
+/*
+ * Set the file modification time zone->expire seconds before expiretime.
+ */
+static void
+setmodtime(dns_zone_t *zone, isc_time_t *expiretime) {
+	isc_result_t result;
+	isc_time_t when;
+	isc_interval_t i;
+
+	isc_interval_set(&i, zone->expire, 0);
+	result = isc_time_subtract(expiretime, &i, &when);
+	if (result != ISC_R_SUCCESS)
+		return;
+
+	result = ISC_R_FAILURE;
+	if (zone->journal != NULL)
+		result = isc_file_settime(zone->journal, &when);
+	if (result == ISC_R_SUCCESS &&
+	    !DNS_ZONE_FLAG(zone, DNS_ZONEFLG_NEEDDUMP) &&
+	    !DNS_ZONE_FLAG(zone, DNS_ZONEFLG_NEEDDUMP))
+		result = isc_file_settime(zone->masterfile, &when);
+	else if (result != ISC_R_SUCCESS)
+		result = isc_file_settime(zone->masterfile, &when);
+
+	/*
+	 * Someone removed the file from underneath us!
+	 */
+	if (result == ISC_R_FILENOTFOUND) {
+		zone_needdump(zone, DNS_DUMP_DELAY);
+	} else if (result != ISC_R_SUCCESS)
+		dns_zone_log(zone, ISC_LOG_ERROR, "refresh: could not set "
+			     "file modification time of '%s': %s",
+			     zone->masterfile, dns_result_totext(result));
+}
+
 /*
  * An SOA query has finished (successfully or not).
  */
@@ -11054,6 +11145,15 @@ refresh_callback(isc_task_t *task, isc_event_t *event) {
 			DNS_ZONE_SETFLAG(zone, DNS_ZONEFLG_NOEDNS);
 			goto same_master;
 		}
+		if (!DNS_ZONE_FLAG(zone, DNS_ZONEFLG_NOEDNS) &&
+		    msg->rcode == dns_rcode_badvers) {
+			dns_zone_log(zone, ISC_LOG_DEBUG(1),
+				     "refresh: rcode (%.*s) retrying without "
+				     "EDNS EXPIRE OPTION master %s (source %s)",
+				     (int)rb.used, rcode, master, source);
+			DNS_ZONE_SETFLAG(zone, DNS_ZONEFLG_NOEDNS);
+			goto same_master;
+		}
 		dns_zone_log(zone, ISC_LOG_INFO,
 			     "refresh: unexpected rcode (%.*s) from "
 			     "master %s (source %s)", (int)rb.used, rcode,
@@ -11219,30 +11319,26 @@ refresh_callback(isc_task_t *task, isc_event_t *event) {
 		if (msg != NULL)
 			dns_message_destroy(&msg);
 	} else if (isc_serial_eq(soa.serial, oldserial)) {
-		if (zone->masterfile != NULL) {
-			result = ISC_R_FAILURE;
-			if (zone->journal != NULL)
-				result = isc_file_settime(zone->journal, &now);
-			if (result == ISC_R_SUCCESS &&
-			    !DNS_ZONE_FLAG(zone, DNS_ZONEFLG_NEEDDUMP) &&
-			    !DNS_ZONE_FLAG(zone, DNS_ZONEFLG_DUMPING)) {
-				result = isc_file_settime(zone->masterfile,
-							  &now);
-			} else if (result != ISC_R_SUCCESS)
-				result = isc_file_settime(zone->masterfile,
-							  &now);
-			/* Someone removed the file from underneath us! */
-			if (result == ISC_R_FILENOTFOUND) {
-				zone_needdump(zone, DNS_DUMP_DELAY);
-			} else if (result != ISC_R_SUCCESS)
-				dns_zone_log(zone, ISC_LOG_ERROR,
-					     "refresh: could not set file "
-					     "modification time of '%s': %s",
-					     zone->masterfile,
-					     dns_result_totext(result));
+		isc_time_t expiretime;
+		isc_uint32_t expire;
+
+		/*
+		 * Compute the new expire time based on this response.
+		 */
+		expire = zone->expire;
+		get_edns_expire(zone, msg, &expire);
+		DNS_ZONE_TIME_ADD(&now, expire, &expiretime);
+
+		/*
+		 * Has the expire time improved?
+		 */
+		if (isc_time_compare(&expiretime, &zone->expiretime) > 0) {
+			zone->expiretime = expiretime;
+			if (zone->masterfile != NULL)
+				setmodtime(zone, &expiretime);
 		}
+
 		DNS_ZONE_JITTER_ADD(&now, zone->refresh, &zone->refreshtime);
-		DNS_ZONE_TIME_ADD(&now, zone->expire, &zone->expiretime);
 		zone->mastersok[zone->curmaster] = ISC_TRUE;
 		goto next_master;
 	} else {
@@ -11416,7 +11512,9 @@ create_query(dns_zone_t *zone, dns_rdatatype_t rdtype,
 }
 
 static isc_result_t
-add_opt(dns_message_t *message, isc_uint16_t udpsize, isc_boolean_t reqnsid) {
+add_opt(dns_message_t *message, isc_uint16_t udpsize, isc_boolean_t reqnsid,
+	isc_boolean_t reqexpire)
+{
 	isc_result_t result;
 	dns_rdataset_t *rdataset = NULL;
 	dns_ednsopt_t ednsopts[DNS_EDNSOPTIONS];
@@ -11430,6 +11528,13 @@ add_opt(dns_message_t *message, isc_uint16_t udpsize, isc_boolean_t reqnsid) {
 		ednsopts[count].value = NULL;
 		count++;
 	}
+	if (reqexpire) {
+		INSIST(count < DNS_EDNSOPTIONS);
+		ednsopts[count].code = DNS_OPT_EXPIRE;
+		ednsopts[count].length = 0;
+		ednsopts[count].value = NULL;
+		count++;
+	}
 	result = dns_message_buildopt(message, &rdataset, 0, udpsize, 0,
 				      ednsopts, count);
 	if (result != ISC_R_SUCCESS)
@@ -11450,7 +11555,7 @@ soa_query(isc_task_t *task, isc_event_t *event) {
 	isc_uint32_t options;
 	isc_boolean_t cancel = ISC_TRUE;
 	int timeout;
-	isc_boolean_t have_xfrsource, have_xfrdscp, reqnsid;
+	isc_boolean_t have_xfrsource, have_xfrdscp, reqnsid, reqexpire;
 	isc_uint16_t udpsize = SEND_BUFFER_SIZE;
 	isc_dscp_t dscp = -1;
 
@@ -11513,6 +11618,7 @@ soa_query(isc_task_t *task, isc_event_t *event) {
 
 	have_xfrsource = have_xfrdscp = ISC_FALSE;
 	reqnsid = zone->view->requestnsid;
+	reqexpire = zone->requestexpire;
 	if (zone->view->peers != NULL) {
 		dns_peer_t *peer = NULL;
 		isc_boolean_t edns;
@@ -11534,6 +11640,7 @@ soa_query(isc_task_t *task, isc_event_t *event) {
 				  dns_resolver_getudpsize(zone->view->resolver);
 			(void)dns_peer_getudpsize(peer, &udpsize);
 			(void)dns_peer_getrequestnsid(peer, &reqnsid);
+			(void)dns_peer_getrequestexpire(peer, &reqexpire);
 		}
 	}
 
@@ -11575,7 +11682,7 @@ soa_query(isc_task_t *task, isc_event_t *event) {
 		  DNS_REQUESTOPT_TCP : 0;
 
 	if (!DNS_ZONE_FLAG(zone, DNS_ZONEFLG_NOEDNS)) {
-		result = add_opt(message, udpsize, reqnsid);
+		result = add_opt(message, udpsize, reqnsid, reqexpire);
 		if (result != ISC_R_SUCCESS)
 			zone_debuglog(zone, me, 1,
 				      "unable to add opt record: %s",
@@ -11790,7 +11897,7 @@ ns_query(dns_zone_t *zone, dns_rdataset_t *soardataset, dns_stub_t *stub) {
 
 	}
 	if (!DNS_ZONE_FLAG(zone, DNS_ZONEFLG_NOEDNS)) {
-		result = add_opt(message, udpsize, reqnsid);
+		result = add_opt(message, udpsize, reqnsid, ISC_FALSE);
 		if (result != ISC_R_SUCCESS)
 			zone_debuglog(zone, me, 1,
 				      "unable to add opt record: %s",
@@ -17308,6 +17415,18 @@ dns_zone_getrequestixfr(dns_zone_t *zone) {
 	return (zone->requestixfr);
 }
 
+void
+dns_zone_setrequestexpire(dns_zone_t *zone, isc_boolean_t flag) {
+	REQUIRE(DNS_ZONE_VALID(zone));
+	zone->requestexpire = flag;
+}
+
+isc_boolean_t
+dns_zone_getrequestexpire(dns_zone_t *zone) {
+	REQUIRE(DNS_ZONE_VALID(zone));
+	return (zone->requestexpire);
+}
+
 void
 dns_zone_setserialupdatemethod(dns_zone_t *zone, dns_updatemethod_t method) {
 	REQUIRE(DNS_ZONE_VALID(zone));

lib/isccfg/namedconf.c

@@ -1675,6 +1675,7 @@ zone_clauses[] = {
 	{ "notify-to-soa", &cfg_type_boolean, 0 },
 	{ "nsec3-test-zone", &cfg_type_boolean, CFG_CLAUSEFLAG_TESTONLY },
 	{ "serial-update-method", &cfg_type_updatemethod, 0 },
+	{ "request-expire", &cfg_type_boolean, 0 },
 	{ "request-ixfr", &cfg_type_boolean, 0 },
 	{ "sig-signing-nodes", &cfg_type_uint32, 0 },
 	{ "sig-signing-signatures", &cfg_type_uint32, 0 },
@@ -1851,6 +1852,7 @@ server_clauses[] = {
 	{ "provide-ixfr", &cfg_type_boolean, 0 },
 	{ "query-source", &cfg_type_querysource4, 0 },
 	{ "query-source-v6", &cfg_type_querysource6, 0 },
+	{ "request-expire", &cfg_type_boolean, 0 },
 	{ "request-ixfr", &cfg_type_boolean, 0 },
 	{ "request-nsid", &cfg_type_boolean, 0 },
 #ifdef ISC_PLATFORM_USESIT