1069. [func] Kill oldest recursive query when recursive query

quota is exhausted.

CHANGES

@@ -1,3 +1,5 @@
+1069.	[func]		Kill oldest recursive query when recursive query				quota is exhausted.
+
 1068.	[bug]		errno could be overwritten by catgets(). [RT #1921]
 
 1067.	[func]		Allow quotas to be soft, isc_quota_soft().

bin/named/client.c

@@ -15,7 +15,7 @@
  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: client.c,v 1.189 2001/10/13 01:10:26 gson Exp $ */
+/* $Id: client.c,v 1.190 2001/10/24 03:10:13 marka Exp $ */
 
 #include <config.h>
 
@@ -95,6 +95,7 @@ struct ns_clientmgr {
 	/* Locked by lock. */
 	isc_boolean_t			exiting;
 	client_list_t			active; 	/* Active clients */
+	client_list_t			recursing; 	/* Recursing clients */
 	client_list_t 			inactive;	/* To be recycled */
 };
 
@@ -173,6 +174,27 @@ static void client_start(isc_task_t *task, isc_event_t *event);
 static void client_request(isc_task_t *task, isc_event_t *event);
 static void ns_client_dumpmessage(ns_client_t *client, const char *reason);
 
+void
+ns_client_recursing(ns_client_t *client, isc_boolean_t killoldest) {
+	ns_client_t *oldest;
+	REQUIRE(NS_CLIENT_VALID(client));
+
+	LOCK(&client->manager->lock);
+	if (killoldest) {
+		oldest = ISC_LIST_HEAD(client->manager->recursing);
+		if (oldest != NULL) {
+			ns_query_cancel(oldest);
+			ISC_LIST_UNLINK(*oldest->list, oldest, link);
+			ISC_LIST_APPEND(client->manager->active, oldest, link);
+			oldest->list = &client->manager->active;
+		}
+	}
+	ISC_LIST_UNLINK(*client->list, client, link);
+	ISC_LIST_APPEND(client->manager->recursing, client, link);
+	client->list = &client->manager->recursing;
+	UNLOCK(&client->manager->lock);
+}
+
 /*
  * Enter the inactive state.
  *
@@ -201,7 +223,7 @@ client_deactivate(ns_client_t *client) {
 	client->mortal = ISC_FALSE;
 
 	LOCK(&client->manager->lock);
-	ISC_LIST_UNLINK(client->manager->active, client, link);
+	ISC_LIST_UNLINK(*client->list, client, link);
 	ISC_LIST_APPEND(client->manager->inactive, client, link);
 	client->list = &client->manager->inactive;
 	UNLOCK(&client->manager->lock);
@@ -251,7 +273,8 @@ client_free(ns_client_t *client) {
 		client->list = NULL;
 		if (manager->exiting &&
 		    ISC_LIST_EMPTY(manager->active) &&
-		    ISC_LIST_EMPTY(manager->inactive))
+		    ISC_LIST_EMPTY(manager->inactive) &&
+		    ISC_LIST_EMPTY(manager->recursing))
 			need_clientmgr_destroy = ISC_TRUE;
 		UNLOCK(&manager->lock);
 	}
@@ -506,7 +529,6 @@ client_shutdown(isc_task_t *task, isc_event_t *event) {
 	(void)exit_check(client);
 }
 
-
 static void
 ns_client_endrequest(ns_client_t *client) {
 	INSIST(client->naccepts == 0);
@@ -1860,6 +1882,7 @@ static void
 clientmgr_destroy(ns_clientmgr_t *manager) {
 	REQUIRE(ISC_LIST_EMPTY(manager->active));
 	REQUIRE(ISC_LIST_EMPTY(manager->inactive));
+	REQUIRE(ISC_LIST_EMPTY(manager->recursing));
 
 	MTRACE("clientmgr_destroy");
 
@@ -1889,6 +1912,7 @@ ns_clientmgr_create(isc_mem_t *mctx, isc_taskmgr_t *taskmgr,
 	manager->exiting = ISC_FALSE;
 	ISC_LIST_INIT(manager->active);
 	ISC_LIST_INIT(manager->inactive);
+	ISC_LIST_INIT(manager->recursing);
 	manager->magic = MANAGER_MAGIC;
 
 	MTRACE("create");
@@ -1919,6 +1943,11 @@ ns_clientmgr_destroy(ns_clientmgr_t **managerp) {
 
 	manager->exiting = ISC_TRUE;
 
+	for (client = ISC_LIST_HEAD(manager->recursing);
+	     client != NULL;
+	     client = ISC_LIST_NEXT(client, link))
+		isc_task_shutdown(client->task);
+
 	for (client = ISC_LIST_HEAD(manager->active);
 	     client != NULL;
 	     client = ISC_LIST_NEXT(client, link))
@@ -1930,7 +1959,8 @@ ns_clientmgr_destroy(ns_clientmgr_t **managerp) {
 		isc_task_shutdown(client->task);
 
 	if (ISC_LIST_EMPTY(manager->active) &&
-	    ISC_LIST_EMPTY(manager->inactive))
+	    ISC_LIST_EMPTY(manager->inactive) &&
+	    ISC_LIST_EMPTY(manager->recursing))
 		need_destroy = ISC_TRUE;
 
 	UNLOCK(&manager->lock);

bin/named/include/named/client.h

@@ -15,7 +15,7 @@
  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: client.h,v 1.61 2001/10/01 18:53:58 gson Exp $ */
+/* $Id: client.h,v 1.62 2001/10/24 03:10:17 marka Exp $ */
 
 #ifndef NAMED_CLIENT_H
 #define NAMED_CLIENT_H 1
@@ -306,4 +306,11 @@ void
 ns_client_aclmsg(const char *msg, dns_name_t *name, dns_rdataclass_t rdclass,
                  char *buf, size_t len);
 
+void
+ns_client_recursing(ns_client_t *client, isc_boolean_t killoldest);
+/*
+ * Add client to end of recursing list.  If 'killoldest' is true
+ * kill the oldest recursive client (list head). 
+ */
+
 #endif /* NAMED_CLIENT_H */

bin/named/include/named/query.h

@@ -15,7 +15,7 @@
  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: query.h,v 1.30 2001/09/21 19:08:06 gson Exp $ */
+/* $Id: query.h,v 1.31 2001/10/24 03:10:18 marka Exp $ */
 
 #ifndef NAMED_QUERY_H
 #define NAMED_QUERY_H 1
@@ -49,6 +49,7 @@ struct ns_query {
 	dns_zone_t *			authzone;
 	isc_boolean_t			authdbset;
 	isc_boolean_t			isreferral;
+	isc_mutex_t			fetchlock;
 	dns_fetch_t *			fetch;
 	dns_a6context_t			a6ctx;
 	isc_bufferlist_t		namebufs;
@@ -84,4 +85,7 @@ ns_query_free(ns_client_t *client);
 void
 ns_query_start(ns_client_t *client);
 
+void
+ns_query_cancel(ns_client_t *client);
+
 #endif /* NAMED_QUERY_H */

bin/named/query.c

@@ -15,7 +15,7 @@
  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: query.c,v 1.205 2001/10/23 06:04:37 marka Exp $ */
+/* $Id: query.c,v 1.206 2001/10/24 03:10:14 marka Exp $ */
 
 #include <config.h>
 
@@ -204,6 +204,17 @@ query_maybeputqname(ns_client_t *client) {
 	}
 }
 
+void
+ns_query_cancel(ns_client_t *client) {
+	LOCK(&client->query.fetchlock);
+	if (client->query.fetch != NULL) {
+		dns_resolver_cancelfetch(client->query.fetch);
+
+		client->query.fetch = NULL;
+	}
+	UNLOCK(&client->query.fetchlock);
+}
+
 static inline void
 query_reset(ns_client_t *client, isc_boolean_t everything) {
 	isc_buffer_t *dbuf, *dbuf_next;
@@ -217,11 +228,7 @@ query_reset(ns_client_t *client, isc_boolean_t everything) {
 	/*
 	 * Cancel the fetch if it's running.
 	 */
-	if (client->query.fetch != NULL) {
-		dns_resolver_cancelfetch(client->query.fetch);
-
-		client->query.fetch = NULL;
-	}
+	ns_query_cancel(client);
 
 	/*
 	 * Cleanup any active versions.
@@ -509,6 +516,9 @@ ns_query_init(ns_client_t *client) {
 	client->query.restarts = 0;
 	client->query.timerset = ISC_FALSE;
 	client->query.qname = NULL;
+	result = isc_mutex_init(&client->query.fetchlock);
+	if (result != ISC_R_SUCCESS)
+		return (result);
 	client->query.fetch = NULL;
 	client->query.authdb = NULL;
 	client->query.authzone = NULL;
@@ -516,13 +526,16 @@ ns_query_init(ns_client_t *client) {
 	client->query.isreferral = ISC_FALSE;	
 	query_reset(client, ISC_FALSE);
 	result = query_newdbversion(client, 3);
-	if (result != ISC_R_SUCCESS)
+	if (result != ISC_R_SUCCESS) {
+		DESTROYLOCK(&client->query.fetchlock);
 		return (result);
+	}
 	dns_a6_init(&client->query.a6ctx, query_simplefind, query_adda6rrset,
 		    NULL, NULL, client);
 	result = query_newnamebuf(client);
 	if (result != ISC_R_SUCCESS) {
 		ns_dbversion_t *dbversion;
+		DESTROYLOCK(&client->query.fetchlock);
 		for (dbversion = ISC_LIST_HEAD(client->query.freeversions);
 		     dbversion != NULL;
 		     dbversion = ISC_LIST_HEAD(client->query.freeversions)) {
@@ -2043,6 +2056,7 @@ query_resume(isc_task_t *task, isc_event_t *event) {
 	REQUIRE(task == client->task);
 	REQUIRE(RECURSING(client));
 
+	LOCK(&client->query.fetchlock);
 	if (client->query.fetch != NULL) {
 		/*
 		 * This is the fetch we've been waiting for.
@@ -2061,6 +2075,7 @@ query_resume(isc_task_t *task, isc_event_t *event) {
 		 */
 		fetch_cancelled = ISC_TRUE;
 	}
+	UNLOCK(&client->query.fetchlock);
 	INSIST(client->query.fetch == NULL);
 
 	client->query.attributes &= ~NS_QUERYATTR_RECURSING;
@@ -2080,7 +2095,10 @@ query_resume(isc_task_t *task, isc_event_t *event) {
 		if (devent->sigrdataset != NULL)
 			query_putrdataset(client, &devent->sigrdataset);
 		isc_event_free(&event);
-		query_next(client, ISC_R_CANCELED);
+		if (fetch_cancelled)
+			query_error(client, DNS_R_SERVFAIL);
+		else
+			query_next(client, ISC_R_CANCELED);
 		/*
 		 * This may destroy the client.
 		 */
@@ -2109,9 +2127,17 @@ query_recurse(ns_client_t *client, dns_rdatatype_t qtype, dns_name_t *qdomain,
 	 * response.
 	 */
 	if (! client->mortal) {
+		isc_boolean_t killoldest = ISC_FALSE;
 		result = isc_quota_attach(&ns_g_server->recursionquota,
 					  &client->recursionquota);
-		if (result == ISC_R_SUCCESS)
+		if (result == ISC_R_SOFTQUOTA) {
+			ns_client_log(client, NS_LOGCATEGORY_CLIENT,
+				      NS_LOGMODULE_QUERY, ISC_LOG_WARNING,
+				      "killing oldest recursive client: %s",
+				      isc_result_totext(result));
+			killoldest = ISC_TRUE;
+		}
+		if (result == ISC_R_SUCCESS || result == ISC_R_SOFTQUOTA)
 			result = ns_client_replace(client);
 		if (result != ISC_R_SUCCESS) {
 			ns_client_log(client, NS_LOGCATEGORY_CLIENT,
@@ -2120,6 +2146,7 @@ query_recurse(ns_client_t *client, dns_rdatatype_t qtype, dns_name_t *qdomain,
 				      isc_result_totext(result));
 			return (result);
 		}
+		ns_client_recursing(client, killoldest);
 	}
 
 	/*

bin/named/server.c

@@ -15,7 +15,7 @@
  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: server.c,v 1.352 2001/10/17 19:34:07 gson Exp $ */
+/* $Id: server.c,v 1.353 2001/10/24 03:10:15 marka Exp $ */
 
 #include <config.h>
 
@@ -2387,6 +2387,7 @@ ns_server_create(isc_mem_t *mctx, ns_server_t **serverp) {
 	RUNTIME_CHECK(result == ISC_R_SUCCESS);
 	result = isc_quota_init(&server->recursionquota, 100);
 	RUNTIME_CHECK(result == ISC_R_SUCCESS);
+	isc_quota_soft(&server->recursionquota, ISC_TRUE);
 
 	result = dns_aclenv_init(mctx, &server->aclenv);
 	RUNTIME_CHECK(result == ISC_R_SUCCESS);