Flatten bind9 vendor work area

1 files changed, 2643 insertions, 0 deletions

diff --git a/bin/named/client.c b/bin/named/client.c
new file mode 100644
index 0000000..b0e9cdd
--- /dev/null
+++ b/bin/named/client.c
@@ -0,0 +1,2643 @@
+/*
+ * Copyright (C) 2004-2007  Internet Systems Consortium, Inc. ("ISC")
+ * Copyright (C) 1999-2003  Internet Software Consortium.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
+ * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+ * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
+ * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+ * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
+ * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+ * PERFORMANCE OF THIS SOFTWARE.
+ */
+
+/* $Id: client.c,v 1.219.18.28 2007/08/28 07:20:00 tbox Exp $ */
+
+#include <config.h>
+
+#include <isc/formatcheck.h>
+#include <isc/mutex.h>
+#include <isc/once.h>
+#include <isc/platform.h>
+#include <isc/print.h>
+#include <isc/stdio.h>
+#include <isc/string.h>
+#include <isc/task.h>
+#include <isc/timer.h>
+#include <isc/util.h>
+
+#include <dns/db.h>
+#include <dns/dispatch.h>
+#include <dns/events.h>
+#include <dns/message.h>
+#include <dns/peer.h>
+#include <dns/rcode.h>
+#include <dns/rdata.h>
+#include <dns/rdataclass.h>
+#include <dns/rdatalist.h>
+#include <dns/rdataset.h>
+#include <dns/resolver.h>
+#include <dns/tsig.h>
+#include <dns/view.h>
+#include <dns/zone.h>
+
+#include <named/interfacemgr.h>
+#include <named/log.h>
+#include <named/notify.h>
+#include <named/server.h>
+#include <named/update.h>
+
+/***
+ *** Client
+ ***/
+
+/*! \file
+ * Client Routines
+ *
+ * Important note!
+ *
+ * All client state changes, other than that from idle to listening, occur
+ * as a result of events.  This guarantees serialization and avoids the
+ * need for locking.
+ *
+ * If a routine is ever created that allows someone other than the client's
+ * task to change the client, then the client will have to be locked.
+ */
+
+#define NS_CLIENT_TRACE
+#ifdef NS_CLIENT_TRACE
+#define CTRACE(m)	ns_client_log(client, \
+				      NS_LOGCATEGORY_CLIENT, \
+				      NS_LOGMODULE_CLIENT, \
+				      ISC_LOG_DEBUG(3), \
+				      "%s", (m))
+#define MTRACE(m)	isc_log_write(ns_g_lctx, \
+				      NS_LOGCATEGORY_GENERAL, \
+				      NS_LOGMODULE_CLIENT, \
+				      ISC_LOG_DEBUG(3), \
+				      "clientmgr @%p: %s", manager, (m))
+#else
+#define CTRACE(m)	((void)(m))
+#define MTRACE(m)	((void)(m))
+#endif
+
+#define TCP_CLIENT(c)	(((c)->attributes & NS_CLIENTATTR_TCP) != 0)
+
+#define TCP_BUFFER_SIZE			(65535 + 2)
+#define SEND_BUFFER_SIZE		4096
+#define RECV_BUFFER_SIZE		4096
+
+#ifdef ISC_PLATFORM_USETHREADS
+#define NMCTXS				100
+/*%<
+ * Number of 'mctx pools' for clients. (Should this be configurable?)
+ * When enabling threads, we use a pool of memory contexts shared by
+ * client objects, since concurrent access to a shared context would cause
+ * heavy contentions.  The above constant is expected to be enough for
+ * completely avoiding contentions among threads for an authoritative-only
+ * server.
+ */
+#else
+#define NMCTXS				0
+/*%<
+ * If named with built without thread, simply share manager's context.  Using
+ * a separate context in this case would simply waste memory.
+ */
+#endif
+
+/*% nameserver client manager structure */
+struct ns_clientmgr {
+	/* Unlocked. */
+	unsigned int			magic;
+	isc_mem_t *			mctx;
+	isc_taskmgr_t *			taskmgr;
+	isc_timermgr_t *		timermgr;
+	isc_mutex_t			lock;
+	/* 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 */
+#if NMCTXS > 0
+	/*%< mctx pool for clients. */
+	unsigned int			nextmctx;
+	isc_mem_t *			mctxpool[NMCTXS];
+#endif
+};
+
+#define MANAGER_MAGIC			ISC_MAGIC('N', 'S', 'C', 'm')
+#define VALID_MANAGER(m)		ISC_MAGIC_VALID(m, MANAGER_MAGIC)
+
+/*! 
+ * Client object states.  Ordering is significant: higher-numbered
+ * states are generally "more active", meaning that the client can
+ * have more dynamically allocated data, outstanding events, etc.
+ * In the list below, any such properties listed for state N
+ * also apply to any state > N.
+ *
+ * To force the client into a less active state, set client->newstate
+ * to that state and call exit_check().  This will cause any
+ * activities defined for higher-numbered states to be aborted.
+ */
+
+#define NS_CLIENTSTATE_FREED    0
+/*%<
+ * The client object no longer exists.
+ */
+
+#define NS_CLIENTSTATE_INACTIVE 1
+/*%<
+ * The client object exists and has a task and timer.
+ * Its "query" struct and sendbuf are initialized.
+ * It is on the client manager's list of inactive clients.
+ * It has a message and OPT, both in the reset state.
+ */
+
+#define NS_CLIENTSTATE_READY    2
+/*%<
+ * The client object is either a TCP or a UDP one, and
+ * it is associated with a network interface.  It is on the
+ * client manager's list of active clients.
+ *
+ * If it is a TCP client object, it has a TCP listener socket
+ * and an outstanding TCP listen request.
+ *
+ * If it is a UDP client object, it has a UDP listener socket
+ * and an outstanding UDP receive request.
+ */
+
+#define NS_CLIENTSTATE_READING  3
+/*%<
+ * The client object is a TCP client object that has received
+ * a connection.  It has a tcpsocket, tcpmsg, TCP quota, and an
+ * outstanding TCP read request.  This state is not used for
+ * UDP client objects.
+ */
+
+#define NS_CLIENTSTATE_WORKING  4
+/*%<
+ * The client object has received a request and is working
+ * on it.  It has a view, and it may have any of a non-reset OPT,
+ * recursion quota, and an outstanding write request.
+ */
+
+#define NS_CLIENTSTATE_MAX      9
+/*%<
+ * Sentinel value used to indicate "no state".  When client->newstate
+ * has this value, we are not attempting to exit the current state.
+ * Must be greater than any valid state.
+ */
+
+/*
+ * Enable ns_client_dropport() by default.
+ */
+#ifndef NS_CLIENT_DROPPORT
+#define NS_CLIENT_DROPPORT 1
+#endif
+
+unsigned int ns_client_requests;
+
+static void client_read(ns_client_t *client);
+static void client_accept(ns_client_t *client);
+static void client_udprecv(ns_client_t *client);
+static void clientmgr_destroy(ns_clientmgr_t *manager);
+static isc_boolean_t exit_check(ns_client_t *client);
+static void ns_client_endrequest(ns_client_t *client);
+static void ns_client_checkactive(ns_client_t *client);
+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) {
+	REQUIRE(NS_CLIENT_VALID(client));
+
+	LOCK(&client->manager->lock);
+	ISC_LIST_UNLINK(*client->list, client, link);
+	ISC_LIST_APPEND(client->manager->recursing, client, link);
+	client->list = &client->manager->recursing;
+	UNLOCK(&client->manager->lock);
+}
+
+void
+ns_client_killoldestquery(ns_client_t *client) {
+	ns_client_t *oldest;
+	REQUIRE(NS_CLIENT_VALID(client));
+
+	LOCK(&client->manager->lock);
+	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;
+	}
+	UNLOCK(&client->manager->lock);
+}
+
+void
+ns_client_settimeout(ns_client_t *client, unsigned int seconds) {
+	isc_result_t result;
+	isc_interval_t interval;
+
+	isc_interval_set(&interval, seconds, 0);
+	result = isc_timer_reset(client->timer, isc_timertype_once, NULL,
+				 &interval, ISC_FALSE);
+	client->timerset = ISC_TRUE;
+	if (result != ISC_R_SUCCESS) {
+		ns_client_log(client, NS_LOGCATEGORY_CLIENT,
+			      NS_LOGMODULE_CLIENT, ISC_LOG_ERROR,
+			      "setting timeout: %s",
+			      isc_result_totext(result));
+		/* Continue anyway. */
+	}
+}
+
+/*%
+ * Check for a deactivation or shutdown request and take appropriate
+ * action.  Returns ISC_TRUE if either is in progress; in this case
+ * the caller must no longer use the client object as it may have been
+ * freed.
+ */
+static isc_boolean_t
+exit_check(ns_client_t *client) {
+	ns_clientmgr_t *locked_manager = NULL;
+	ns_clientmgr_t *destroy_manager = NULL;
+
+	REQUIRE(NS_CLIENT_VALID(client));
+
+	if (client->state <= client->newstate)
+		return (ISC_FALSE); /* Business as usual. */
+
+	INSIST(client->newstate < NS_CLIENTSTATE_WORKING);
+
+	/*
+	 * We need to detach from the view early when shutting down
+	 * the server to break the following vicious circle:
+	 *
+	 *  - The resolver will not shut down until the view refcount is zero
+	 *  - The view refcount does not go to zero until all clients detach
+	 *  - The client does not detach from the view until references is zero
+	 *  - references does not go to zero until the resolver has shut down
+	 *
+	 * Keep the view attached until any outstanding updates complete.
+	 */
+	if (client->nupdates == 0 && 
+	    client->newstate == NS_CLIENTSTATE_FREED && client->view != NULL)
+		dns_view_detach(&client->view);
+
+	if (client->state == NS_CLIENTSTATE_WORKING) {
+		INSIST(client->newstate <= NS_CLIENTSTATE_READING);
+		/*
+		 * Let the update processing complete.
+		 */
+		if (client->nupdates > 0)
+			return (ISC_TRUE);
+		/*
+		 * We are trying to abort request processing.
+		 */
+		if (client->nsends > 0) {
+			isc_socket_t *socket;
+			if (TCP_CLIENT(client))
+				socket = client->tcpsocket;
+			else
+				socket = client->udpsocket;
+			isc_socket_cancel(socket, client->task,
+					  ISC_SOCKCANCEL_SEND);
+		}
+
+		if (! (client->nsends == 0 && client->nrecvs == 0 &&
+		       client->references == 0))
+		{
+			/*
+			 * Still waiting for I/O cancel completion.
+			 * or lingering references.
+			 */
+			return (ISC_TRUE);
+		}
+		/*
+		 * I/O cancel is complete.  Burn down all state
+		 * related to the current request.  Ensure that
+		 * the client is on the active list and not the
+		 * recursing list.
+		 */
+		LOCK(&client->manager->lock);
+		if (client->list == &client->manager->recursing) {
+			ISC_LIST_UNLINK(*client->list, client, link);
+			ISC_LIST_APPEND(client->manager->active, client, link);
+			client->list = &client->manager->active;
+		}
+		UNLOCK(&client->manager->lock);
+		ns_client_endrequest(client);
+
+		client->state = NS_CLIENTSTATE_READING;
+		INSIST(client->recursionquota == NULL);
+		if (NS_CLIENTSTATE_READING == client->newstate) {
+			client_read(client);
+			client->newstate = NS_CLIENTSTATE_MAX;
+			return (ISC_TRUE); /* We're done. */
+		}
+	}
+
+	if (client->state == NS_CLIENTSTATE_READING) {
+		/*
+		 * We are trying to abort the current TCP connection,
+		 * if any.
+		 */
+		INSIST(client->recursionquota == NULL);
+		INSIST(client->newstate <= NS_CLIENTSTATE_READY);
+		if (client->nreads > 0)
+			dns_tcpmsg_cancelread(&client->tcpmsg);
+		if (! client->nreads == 0) {
+			/* Still waiting for read cancel completion. */
+			return (ISC_TRUE);
+		}
+
+		if (client->tcpmsg_valid) {
+			dns_tcpmsg_invalidate(&client->tcpmsg);
+			client->tcpmsg_valid = ISC_FALSE;
+		}
+		if (client->tcpsocket != NULL) {
+			CTRACE("closetcp");
+			isc_socket_detach(&client->tcpsocket);
+		}
+
+		if (client->tcpquota != NULL)
+			isc_quota_detach(&client->tcpquota);
+
+		if (client->timerset) {
+			(void)isc_timer_reset(client->timer,
+					      isc_timertype_inactive,
+					      NULL, NULL, ISC_TRUE);
+			client->timerset = ISC_FALSE;
+		}
+
+		client->peeraddr_valid = ISC_FALSE;
+
+		client->state = NS_CLIENTSTATE_READY;
+		INSIST(client->recursionquota == NULL);
+
+		/*
+		 * Now the client is ready to accept a new TCP connection
+		 * or UDP request, but we may have enough clients doing
+		 * that already.  Check whether this client needs to remain
+		 * active and force it to go inactive if not.
+		 */
+		ns_client_checkactive(client);
+
+		if (NS_CLIENTSTATE_READY == client->newstate) {
+			if (TCP_CLIENT(client)) {
+				client_accept(client);
+			} else
+				client_udprecv(client);
+			client->newstate = NS_CLIENTSTATE_MAX;
+			return (ISC_TRUE);
+		}
+	}
+
+	if (client->state == NS_CLIENTSTATE_READY) {
+		INSIST(client->newstate <= NS_CLIENTSTATE_INACTIVE);
+		/*
+		 * We are trying to enter the inactive state.
+		 */
+		if (client->naccepts > 0)
+			isc_socket_cancel(client->tcplistener, client->task,
+					  ISC_SOCKCANCEL_ACCEPT);
+
+		if (! (client->naccepts == 0)) {
+			/* Still waiting for accept cancel completion. */
+			return (ISC_TRUE);
+		}
+		/* Accept cancel is complete. */
+
+		if (client->nrecvs > 0)
+			isc_socket_cancel(client->udpsocket, client->task,
+					  ISC_SOCKCANCEL_RECV);
+		if (! (client->nrecvs == 0)) {
+			/* Still waiting for recv cancel completion. */
+			return (ISC_TRUE);
+		}
+		/* Recv cancel is complete. */
+
+		if (client->nctls > 0) {
+			/* Still waiting for control event to be delivered */
+			return (ISC_TRUE);
+		}
+
+		/* Deactivate the client. */
+		if (client->interface)
+			ns_interface_detach(&client->interface);
+
+		INSIST(client->naccepts == 0);
+		INSIST(client->recursionquota == NULL);
+		if (client->tcplistener != NULL)
+			isc_socket_detach(&client->tcplistener);
+
+		if (client->udpsocket != NULL)
+			isc_socket_detach(&client->udpsocket);
+
+		if (client->dispatch != NULL)
+			dns_dispatch_detach(&client->dispatch);
+
+		client->attributes = 0;
+		client->mortal = ISC_FALSE;
+
+		LOCK(&client->manager->lock);
+		/*
+		 * Put the client on the inactive list.  If we are aiming for
+		 * the "freed" state, it will be removed from the inactive
+		 * list shortly, and we need to keep the manager locked until
+		 * that has been done, lest the manager decide to reactivate
+		 * the dying client inbetween.
+		 */
+		locked_manager = client->manager;
+		ISC_LIST_UNLINK(*client->list, client, link);
+		ISC_LIST_APPEND(client->manager->inactive, client, link);
+		client->list = &client->manager->inactive;
+		client->state = NS_CLIENTSTATE_INACTIVE;
+		INSIST(client->recursionquota == NULL);
+
+		if (client->state == client->newstate) {
+			client->newstate = NS_CLIENTSTATE_MAX;
+			goto unlock;
+		}
+	}
+
+	if (client->state == NS_CLIENTSTATE_INACTIVE) {
+		INSIST(client->newstate == NS_CLIENTSTATE_FREED);
+		/*
+		 * We are trying to free the client.
+		 *
+		 * When "shuttingdown" is true, either the task has received
+		 * its shutdown event or no shutdown event has ever been
+		 * set up.  Thus, we have no outstanding shutdown
+		 * event at this point.
+		 */
+		REQUIRE(client->state == NS_CLIENTSTATE_INACTIVE);
+
+		INSIST(client->recursionquota == NULL);
+
+		ns_query_free(client);
+		isc_mem_put(client->mctx, client->recvbuf, RECV_BUFFER_SIZE);
+		isc_event_free((isc_event_t **)&client->sendevent);
+		isc_event_free((isc_event_t **)&client->recvevent);
+		isc_timer_detach(&client->timer);
+
+		if (client->tcpbuf != NULL)
+			isc_mem_put(client->mctx, client->tcpbuf, TCP_BUFFER_SIZE);
+		if (client->opt != NULL) {
+			INSIST(dns_rdataset_isassociated(client->opt));
+			dns_rdataset_disassociate(client->opt);
+			dns_message_puttemprdataset(client->message, &client->opt);
+		}
+		dns_message_destroy(&client->message);
+		if (client->manager != NULL) {
+			ns_clientmgr_t *manager = client->manager;
+			if (locked_manager == NULL) {
+				LOCK(&manager->lock);
+				locked_manager = manager;
+			}
+			ISC_LIST_UNLINK(*client->list, client, link);
+			client->list = NULL;
+			if (manager->exiting &&
+			    ISC_LIST_EMPTY(manager->active) &&
+			    ISC_LIST_EMPTY(manager->inactive) &&
+			    ISC_LIST_EMPTY(manager->recursing))
+				destroy_manager = manager;
+		}
+		/*
+		 * Detaching the task must be done after unlinking from
+		 * the manager's lists because the manager accesses
+		 * client->task.
+		 */
+		if (client->task != NULL)
+			isc_task_detach(&client->task);
+
+		CTRACE("free");
+		client->magic = 0;
+		isc_mem_putanddetach(&client->mctx, client, sizeof(*client));
+
+		goto unlock;
+	}
+
+ unlock:
+	if (locked_manager != NULL) {
+		UNLOCK(&locked_manager->lock);
+		locked_manager = NULL;
+	}
+
+	/*
+	 * Only now is it safe to destroy the client manager (if needed),
+	 * because we have accessed its lock for the last time.
+	 */
+	if (destroy_manager != NULL)
+		clientmgr_destroy(destroy_manager);
+
+	return (ISC_TRUE);
+}
+
+/*%
+ * The client's task has received the client's control event
+ * as part of the startup process.
+ */
+static void
+client_start(isc_task_t *task, isc_event_t *event) {
+	ns_client_t *client = (ns_client_t *) event->ev_arg;
+
+	INSIST(task == client->task);
+
+	UNUSED(task);
+
+	INSIST(client->nctls == 1);
+	client->nctls--;
+
+	if (exit_check(client))
+		return;
+
+	if (TCP_CLIENT(client)) {
+		client_accept(client);
+	} else {
+		client_udprecv(client);
+	}
+}
+
+
+/*%
+ * The client's task has received a shutdown event.
+ */
+static void
+client_shutdown(isc_task_t *task, isc_event_t *event) {
+	ns_client_t *client;
+
+	REQUIRE(event != NULL);
+	REQUIRE(event->ev_type == ISC_TASKEVENT_SHUTDOWN);
+	client = event->ev_arg;
+	REQUIRE(NS_CLIENT_VALID(client));
+	REQUIRE(task == client->task);
+
+	UNUSED(task);
+
+	CTRACE("shutdown");
+
+	isc_event_free(&event);
+
+	if (client->shutdown != NULL) {
+		(client->shutdown)(client->shutdown_arg, ISC_R_SHUTTINGDOWN);
+		client->shutdown = NULL;
+		client->shutdown_arg = NULL;
+	}
+
+	client->newstate = NS_CLIENTSTATE_FREED;
+	(void)exit_check(client);
+}
+
+static void
+ns_client_endrequest(ns_client_t *client) {
+	INSIST(client->naccepts == 0);
+	INSIST(client->nreads == 0);
+	INSIST(client->nsends == 0);
+	INSIST(client->nrecvs == 0);
+	INSIST(client->nupdates == 0);
+	INSIST(client->state == NS_CLIENTSTATE_WORKING);
+
+	CTRACE("endrequest");
+
+	if (client->next != NULL) {
+		(client->next)(client);
+		client->next = NULL;
+	}
+
+	if (client->view != NULL)
+		dns_view_detach(&client->view);
+	if (client->opt != NULL) {
+		INSIST(dns_rdataset_isassociated(client->opt));
+		dns_rdataset_disassociate(client->opt);
+		dns_message_puttemprdataset(client->message, &client->opt);
+	}
+
+	client->udpsize = 512;
+	client->extflags = 0;
+	client->ednsversion = -1;
+	dns_message_reset(client->message, DNS_MESSAGE_INTENTPARSE);
+
+	if (client->recursionquota != NULL)
+		isc_quota_detach(&client->recursionquota);
+
+	/*
+	 * Clear all client attributes that are specific to
+	 * the request; that's all except the TCP flag.
+	 */
+	client->attributes &= NS_CLIENTATTR_TCP;
+}
+
+static void
+ns_client_checkactive(ns_client_t *client) {
+	if (client->mortal) {
+		/*
+		 * This client object should normally go inactive
+		 * at this point, but if we have fewer active client
+		 * objects than  desired due to earlier quota exhaustion,
+		 * keep it active to make up for the shortage.
+		 */
+		isc_boolean_t need_another_client = ISC_FALSE;
+		if (TCP_CLIENT(client)) {
+			LOCK(&client->interface->lock);
+			if (client->interface->ntcpcurrent <
+			    client->interface->ntcptarget)
+				need_another_client = ISC_TRUE;
+			UNLOCK(&client->interface->lock);
+		} else {
+			/*
+			 * The UDP client quota is enforced by making
+			 * requests fail rather than by not listening
+			 * for new ones.  Therefore, there is always a
+			 * full set of UDP clients listening.
+			 */
+		}
+		if (! need_another_client) {
+			/*
+			 * We don't need this client object.  Recycle it.
+			 */
+			if (client->newstate >= NS_CLIENTSTATE_INACTIVE)
+				client->newstate = NS_CLIENTSTATE_INACTIVE;
+		}
+	}
+}
+
+void
+ns_client_next(ns_client_t *client, isc_result_t result) {
+	int newstate;
+
+	REQUIRE(NS_CLIENT_VALID(client));
+	REQUIRE(client->state == NS_CLIENTSTATE_WORKING ||
+		client->state == NS_CLIENTSTATE_READING);
+
+	CTRACE("next");
+
+	if (result != ISC_R_SUCCESS)
+		ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
+			      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(3),
+			      "request failed: %s", isc_result_totext(result));
+
+	/*
+	 * An error processing a TCP request may have left
+	 * the connection out of sync.  To be safe, we always
+	 * sever the connection when result != ISC_R_SUCCESS.
+	 */
+	if (result == ISC_R_SUCCESS && TCP_CLIENT(client))
+		newstate = NS_CLIENTSTATE_READING;
+	else
+		newstate = NS_CLIENTSTATE_READY;
+
+	if (client->newstate > newstate)
+		client->newstate = newstate;
+	(void)exit_check(client);
+}
+
+
+static void
+client_senddone(isc_task_t *task, isc_event_t *event) {
+	ns_client_t *client;
+	isc_socketevent_t *sevent = (isc_socketevent_t *) event;
+
+	REQUIRE(sevent != NULL);
+	REQUIRE(sevent->ev_type == ISC_SOCKEVENT_SENDDONE);
+	client = sevent->ev_arg;
+	REQUIRE(NS_CLIENT_VALID(client));
+	REQUIRE(task == client->task);
+	REQUIRE(sevent == client->sendevent);
+
+	UNUSED(task);
+
+	CTRACE("senddone");
+
+	if (sevent->result != ISC_R_SUCCESS)
+		ns_client_log(client, NS_LOGCATEGORY_CLIENT,
+			      NS_LOGMODULE_CLIENT, ISC_LOG_WARNING,
+			      "error sending response: %s",
+			      isc_result_totext(sevent->result));
+
+	INSIST(client->nsends > 0);
+	client->nsends--;
+
+	if (client->tcpbuf != NULL) {
+		INSIST(TCP_CLIENT(client));
+		isc_mem_put(client->mctx, client->tcpbuf, TCP_BUFFER_SIZE);
+		client->tcpbuf = NULL;
+	}
+
+	if (exit_check(client))
+		return;
+
+	ns_client_next(client, ISC_R_SUCCESS);
+}
+
+/*%
+ * We only want to fail with ISC_R_NOSPACE when called from
+ * ns_client_sendraw() and not when called from ns_client_send(),
+ * tcpbuffer is NULL when called from ns_client_sendraw() and
+ * length != 0.  tcpbuffer != NULL when called from ns_client_send()
+ * and length == 0.
+ */
+
+static isc_result_t
+client_allocsendbuf(ns_client_t *client, isc_buffer_t *buffer,
+		    isc_buffer_t *tcpbuffer, isc_uint32_t length,
+		    unsigned char *sendbuf, unsigned char **datap)
+{
+	unsigned char *data;
+	isc_uint32_t bufsize;
+	isc_result_t result;
+
+	INSIST(datap != NULL);
+	INSIST((tcpbuffer == NULL && length != 0) ||
+	       (tcpbuffer != NULL && length == 0));
+
+	if (TCP_CLIENT(client)) {
+		INSIST(client->tcpbuf == NULL);
+		if (length + 2 > TCP_BUFFER_SIZE) {
+			result = ISC_R_NOSPACE;
+			goto done;
+		}
+		client->tcpbuf = isc_mem_get(client->mctx, TCP_BUFFER_SIZE);
+		if (client->tcpbuf == NULL) {
+			result = ISC_R_NOMEMORY;
+			goto done;
+		}
+		data = client->tcpbuf;
+		if (tcpbuffer != NULL) {
+			isc_buffer_init(tcpbuffer, data, TCP_BUFFER_SIZE);
+			isc_buffer_init(buffer, data + 2, TCP_BUFFER_SIZE - 2);
+		} else {
+			isc_buffer_init(buffer, data, TCP_BUFFER_SIZE);
+			INSIST(length <= 0xffff);
+			isc_buffer_putuint16(buffer, (isc_uint16_t)length);
+		}
+	} else {
+		data = sendbuf;
+		if (client->udpsize < SEND_BUFFER_SIZE)
+			bufsize = client->udpsize;
+		else
+			bufsize = SEND_BUFFER_SIZE;
+		if (length > bufsize) {
+			result = ISC_R_NOSPACE;
+			goto done;
+		}
+		isc_buffer_init(buffer, data, bufsize);
+	}
+	*datap = data;
+	result = ISC_R_SUCCESS;
+
+ done:
+	return (result);
+}
+
+static isc_result_t
+client_sendpkg(ns_client_t *client, isc_buffer_t *buffer) {
+	struct in6_pktinfo *pktinfo;
+	isc_result_t result;
+	isc_region_t r;
+	isc_sockaddr_t *address;
+	isc_socket_t *socket;
+	isc_netaddr_t netaddr;
+	int match;
+	unsigned int sockflags = ISC_SOCKFLAG_IMMEDIATE;
+
+	if (TCP_CLIENT(client)) {
+		socket = client->tcpsocket;
+		address = NULL;
+	} else {
+		socket = client->udpsocket;
+		address = &client->peeraddr;
+
+		isc_netaddr_fromsockaddr(&netaddr, &client->peeraddr);
+		if (ns_g_server->blackholeacl != NULL &&
+		    dns_acl_match(&netaddr, NULL,
+			    	  ns_g_server->blackholeacl,
+				  &ns_g_server->aclenv,
+				  &match, NULL) == ISC_R_SUCCESS &&
+		    match > 0)
+			return (DNS_R_BLACKHOLED);
+		sockflags |= ISC_SOCKFLAG_NORETRY;
+	}
+
+	if ((client->attributes & NS_CLIENTATTR_PKTINFO) != 0 &&
+	    (client->attributes & NS_CLIENTATTR_MULTICAST) == 0)
+		pktinfo = &client->pktinfo;
+	else
+		pktinfo = NULL;
+
+	isc_buffer_usedregion(buffer, &r);
+
+	CTRACE("sendto");
+	
+	result = isc_socket_sendto2(socket, &r, client->task,
+				    address, pktinfo,
+				    client->sendevent, sockflags);
+	if (result == ISC_R_SUCCESS || result == ISC_R_INPROGRESS) {
+		client->nsends++;
+		if (result == ISC_R_SUCCESS)
+			client_senddone(client->task,
+					(isc_event_t *)client->sendevent);
+		result = ISC_R_SUCCESS;
+	}
+	return (result);
+}
+
+void
+ns_client_sendraw(ns_client_t *client, dns_message_t *message) {
+	isc_result_t result;
+	unsigned char *data;
+	isc_buffer_t buffer;
+	isc_region_t r;
+	isc_region_t *mr;
+	unsigned char sendbuf[SEND_BUFFER_SIZE];
+
+	REQUIRE(NS_CLIENT_VALID(client));
+
+	CTRACE("sendraw");
+
+	mr = dns_message_getrawmessage(message);
+	if (mr == NULL) {
+		result = ISC_R_UNEXPECTEDEND;
+		goto done;
+	}
+
+	result = client_allocsendbuf(client, &buffer, NULL, mr->length,
+				     sendbuf, &data);
+	if (result != ISC_R_SUCCESS)
+		goto done;
+
+	/*
+	 * Copy message to buffer and fixup id.
+	 */
+	isc_buffer_availableregion(&buffer, &r);
+	result = isc_buffer_copyregion(&buffer, mr);
+	if (result != ISC_R_SUCCESS)
+		goto done;
+	r.base[0] = (client->message->id >> 8) & 0xff;
+	r.base[1] = client->message->id & 0xff;
+
+	result = client_sendpkg(client, &buffer);
+	if (result == ISC_R_SUCCESS)
+		return;
+
+ done:
+	if (client->tcpbuf != NULL) {
+		isc_mem_put(client->mctx, client->tcpbuf, TCP_BUFFER_SIZE);
+		client->tcpbuf = NULL;
+	}
+	ns_client_next(client, result);
+}
+
+void
+ns_client_send(ns_client_t *client) {
+	isc_result_t result;
+	unsigned char *data;
+	isc_buffer_t buffer;
+	isc_buffer_t tcpbuffer;
+	isc_region_t r;
+	dns_compress_t cctx;
+	isc_boolean_t cleanup_cctx = ISC_FALSE;
+	unsigned char sendbuf[SEND_BUFFER_SIZE];
+	unsigned int dnssec_opts;
+	unsigned int preferred_glue;
+
+	REQUIRE(NS_CLIENT_VALID(client));
+
+	CTRACE("send");
+
+	if ((client->attributes & NS_CLIENTATTR_RA) != 0)
+		client->message->flags |= DNS_MESSAGEFLAG_RA;
+
+	if ((client->attributes & NS_CLIENTATTR_WANTDNSSEC) != 0)
+		dnssec_opts = 0;
+	else
+		dnssec_opts = DNS_MESSAGERENDER_OMITDNSSEC;
+
+	preferred_glue = 0;
+	if (client->view != NULL) {
+		if (client->view->preferred_glue == dns_rdatatype_a)
+			preferred_glue = DNS_MESSAGERENDER_PREFER_A;
+		else if (client->view->preferred_glue == dns_rdatatype_aaaa)
+			preferred_glue = DNS_MESSAGERENDER_PREFER_AAAA;
+	}
+
+	/*
+	 * XXXRTH  The following doesn't deal with TCP buffer resizing.
+	 */
+	result = client_allocsendbuf(client, &buffer, &tcpbuffer, 0,
+				     sendbuf, &data);
+	if (result != ISC_R_SUCCESS)
+		goto done;
+
+	result = dns_compress_init(&cctx, -1, client->mctx);
+	if (result != ISC_R_SUCCESS)
+		goto done;
+	cleanup_cctx = ISC_TRUE;
+
+	result = dns_message_renderbegin(client->message, &cctx, &buffer);
+	if (result != ISC_R_SUCCESS)
+		goto done;
+	if (client->opt != NULL) {
+		result = dns_message_setopt(client->message, client->opt);
+		/*
+		 * XXXRTH dns_message_setopt() should probably do this...
+		 */
+		client->opt = NULL;
+		if (result != ISC_R_SUCCESS)
+			goto done;
+	}
+	result = dns_message_rendersection(client->message,
+					   DNS_SECTION_QUESTION, 0);
+	if (result == ISC_R_NOSPACE) {
+		client->message->flags |= DNS_MESSAGEFLAG_TC;
+		goto renderend;
+	}
+	if (result != ISC_R_SUCCESS)
+		goto done;
+	result = dns_message_rendersection(client->message,
+					   DNS_SECTION_ANSWER,
+					   DNS_MESSAGERENDER_PARTIAL |
+					   dnssec_opts);
+	if (result == ISC_R_NOSPACE) {
+		client->message->flags |= DNS_MESSAGEFLAG_TC;
+		goto renderend;
+	}
+	if (result != ISC_R_SUCCESS)
+		goto done;
+	result = dns_message_rendersection(client->message,
+					   DNS_SECTION_AUTHORITY,
+					   DNS_MESSAGERENDER_PARTIAL |
+					   dnssec_opts);
+	if (result == ISC_R_NOSPACE) {
+		client->message->flags |= DNS_MESSAGEFLAG_TC;
+		goto renderend;
+	}
+	if (result != ISC_R_SUCCESS)
+		goto done;
+	result = dns_message_rendersection(client->message,
+					   DNS_SECTION_ADDITIONAL,
+					   preferred_glue | dnssec_opts);
+	if (result != ISC_R_SUCCESS && result != ISC_R_NOSPACE)
+		goto done;
+ renderend:
+	result = dns_message_renderend(client->message);
+
+	if (result != ISC_R_SUCCESS)
+		goto done;
+
+	if (cleanup_cctx) {
+		dns_compress_invalidate(&cctx);
+		cleanup_cctx = ISC_FALSE;
+	}
+
+	if (TCP_CLIENT(client)) {
+		isc_buffer_usedregion(&buffer, &r);
+		isc_buffer_putuint16(&tcpbuffer, (isc_uint16_t) r.length);
+		isc_buffer_add(&tcpbuffer, r.length);
+		result = client_sendpkg(client, &tcpbuffer);
+	} else
+		result = client_sendpkg(client, &buffer);
+	if (result == ISC_R_SUCCESS)
+		return;
+
+ done:
+	if (client->tcpbuf != NULL) {
+		isc_mem_put(client->mctx, client->tcpbuf, TCP_BUFFER_SIZE);
+		client->tcpbuf = NULL;
+	}
+
+	if (cleanup_cctx)
+		dns_compress_invalidate(&cctx);
+
+	ns_client_next(client, result);
+}
+
+#if NS_CLIENT_DROPPORT
+#define DROPPORT_NO		0
+#define DROPPORT_REQUEST	1
+#define DROPPORT_RESPONSE	2
+/*%
+ * ns_client_dropport determines if certain requests / responses
+ * should be dropped based on the port number.
+ *
+ * Returns:
+ * \li	0:	Don't drop.
+ * \li	1:	Drop request.
+ * \li	2:	Drop (error) response.
+ */
+static int
+ns_client_dropport(in_port_t port) {
+	switch (port) {
+	case 7: /* echo */
+	case 13: /* daytime */
+	case 19: /* chargen */
+	case 37: /* time */
+		return (DROPPORT_REQUEST);
+	case 464: /* kpasswd */
+		return (DROPPORT_RESPONSE);
+	}
+	return (DROPPORT_NO);
+}
+#endif
+
+void
+ns_client_error(ns_client_t *client, isc_result_t result) {
+	dns_rcode_t rcode;
+	dns_message_t *message;
+
+	REQUIRE(NS_CLIENT_VALID(client));
+
+	CTRACE("error");
+
+	message = client->message;
+	rcode = dns_result_torcode(result);
+
+#if NS_CLIENT_DROPPORT
+	/*
+	 * Don't send FORMERR to ports on the drop port list.
+	 */
+	if (rcode == dns_rcode_formerr &&
+	    ns_client_dropport(isc_sockaddr_getport(&client->peeraddr)) !=
+	    DROPPORT_NO) {
+		char buf[64];
+		isc_buffer_t b;
+
+		isc_buffer_init(&b, buf, sizeof(buf) - 1);
+		if (dns_rcode_totext(rcode, &b) != ISC_R_SUCCESS)
+			isc_buffer_putstr(&b, "UNKNOWN RCODE");
+		ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
+			      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(10),
+			      "dropped error (%.*s) response: suspicious port",
+			      (int)isc_buffer_usedlength(&b), buf);
+		ns_client_next(client, ISC_R_SUCCESS);
+		return;
+	}
+#endif
+
+	/*
+	 * Message may be an in-progress reply that we had trouble
+	 * with, in which case QR will be set.  We need to clear QR before
+	 * calling dns_message_reply() to avoid triggering an assertion.
+	 */
+	message->flags &= ~DNS_MESSAGEFLAG_QR;
+	/*
+	 * AA and AD shouldn't be set.
+	 */
+	message->flags &= ~(DNS_MESSAGEFLAG_AA | DNS_MESSAGEFLAG_AD);
+	result = dns_message_reply(message, ISC_TRUE);
+	if (result != ISC_R_SUCCESS) {
+		/*
+		 * It could be that we've got a query with a good header,
+		 * but a bad question section, so we try again with
+		 * want_question_section set to ISC_FALSE.
+		 */
+		result = dns_message_reply(message, ISC_FALSE);
+		if (result != ISC_R_SUCCESS) {
+			ns_client_next(client, result);
+			return;
+		}
+	}
+	message->rcode = rcode;
+
+	/*
+	 * FORMERR loop avoidance:  If we sent a FORMERR message
+	 * with the same ID to the same client less than two
+	 * seconds ago, assume that we are in an infinite error 
+	 * packet dialog with a server for some protocol whose 
+	 * error responses look enough like DNS queries to
+	 * elicit a FORMERR response.  Drop a packet to break
+	 * the loop.
+	 */
+	if (rcode == dns_rcode_formerr) {
+		if (isc_sockaddr_equal(&client->peeraddr,
+				       &client->formerrcache.addr) &&
+		    message->id == client->formerrcache.id &&
+		    client->requesttime - client->formerrcache.time < 2) {
+			/* Drop packet. */
+			ns_client_log(client, NS_LOGCATEGORY_CLIENT,
+				      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(1),
+				      "possible error packet loop, "
+				      "FORMERR dropped");
+			ns_client_next(client, result);
+			return;
+		}
+		client->formerrcache.addr = client->peeraddr;
+		client->formerrcache.time = client->requesttime;
+		client->formerrcache.id = message->id;
+	}
+	ns_client_send(client);
+}
+
+static inline isc_result_t
+client_addopt(ns_client_t *client) {
+	dns_rdataset_t *rdataset;
+	dns_rdatalist_t *rdatalist;
+	dns_rdata_t *rdata;
+	isc_result_t result;
+	dns_view_t *view;
+	dns_resolver_t *resolver;
+	isc_uint16_t udpsize;
+
+	REQUIRE(client->opt == NULL);	/* XXXRTH free old. */
+
+	rdatalist = NULL;
+	result = dns_message_gettemprdatalist(client->message, &rdatalist);
+	if (result != ISC_R_SUCCESS)
+		return (result);
+	rdata = NULL;
+	result = dns_message_gettemprdata(client->message, &rdata);
+	if (result != ISC_R_SUCCESS)
+		return (result);
+	rdataset = NULL;
+	result = dns_message_gettemprdataset(client->message, &rdataset);
+	if (result != ISC_R_SUCCESS)
+		return (result);
+	dns_rdataset_init(rdataset);
+
+	rdatalist->type = dns_rdatatype_opt;
+	rdatalist->covers = 0;
+
+	/*
+	 * Set the maximum UDP buffer size.
+	 */
+	view = client->view;
+	resolver = (view != NULL) ? view->resolver : NULL;
+	if (resolver != NULL)
+		udpsize = dns_resolver_getudpsize(resolver);
+	else
+		udpsize = ns_g_udpsize;
+	rdatalist->rdclass = udpsize;
+
+	/*
+	 * Set EXTENDED-RCODE, VERSION and Z to 0.
+	 */
+	rdatalist->ttl = (client->extflags & DNS_MESSAGEEXTFLAG_REPLYPRESERVE);
+
+	/*
+	 * No EDNS options in the default case.
+	 */
+	rdata->data = NULL;
+	rdata->length = 0;
+	rdata->rdclass = rdatalist->rdclass;
+	rdata->type = rdatalist->type;
+	rdata->flags = 0;
+
+	ISC_LIST_INIT(rdatalist->rdata);
+	ISC_LIST_APPEND(rdatalist->rdata, rdata, link);
+	RUNTIME_CHECK(dns_rdatalist_tordataset(rdatalist, rdataset)
+		      == ISC_R_SUCCESS);
+
+	client->opt = rdataset;
+
+	return (ISC_R_SUCCESS);
+}
+
+static inline isc_boolean_t
+allowed(isc_netaddr_t *addr, dns_name_t *signer, dns_acl_t *acl) {
+	int match;
+	isc_result_t result;
+
+	if (acl == NULL)
+		return (ISC_TRUE);
+	result = dns_acl_match(addr, signer, acl, &ns_g_server->aclenv,
+			       &match, NULL);
+	if (result == ISC_R_SUCCESS && match > 0)
+		return (ISC_TRUE);
+	return (ISC_FALSE);
+}
+
+/*
+ * Callback to see if a non-recursive query coming from 'srcaddr' to
+ * 'destaddr', with optional key 'mykey' for class 'rdclass' would be
+ * delivered to 'myview'.
+ *
+ * We run this unlocked as both the view list and the interface list
+ * are updated when the approprite task has exclusivity.
+ */
+isc_boolean_t
+ns_client_isself(dns_view_t *myview, dns_tsigkey_t *mykey,
+		 isc_sockaddr_t *srcaddr, isc_sockaddr_t *dstaddr,
+		 dns_rdataclass_t rdclass, void *arg)
+{
+	dns_view_t *view;
+	dns_tsigkey_t *key = NULL;
+	dns_name_t *tsig = NULL;
+	isc_netaddr_t netsrc;
+	isc_netaddr_t netdst;
+
+	UNUSED(arg);
+
+	if (!ns_interfacemgr_listeningon(ns_g_server->interfacemgr, dstaddr))
+		return (ISC_FALSE);
+
+	isc_netaddr_fromsockaddr(&netsrc, srcaddr);
+	isc_netaddr_fromsockaddr(&netdst, dstaddr);
+
+	for (view = ISC_LIST_HEAD(ns_g_server->viewlist);
+	     view != NULL;
+	     view = ISC_LIST_NEXT(view, link)) {
+
+		if (view->matchrecursiveonly)
+			continue;
+
+		if (rdclass != view->rdclass)
+			continue;
+
+		if (mykey != NULL) {
+			isc_boolean_t match;
+			isc_result_t result;
+
+			tsig = &mykey->name;
+			result = dns_view_gettsig(view, tsig, &key);
+			if (result != ISC_R_SUCCESS)
+				continue;
+			match = dst_key_compare(mykey->key, key->key);
+			dns_tsigkey_detach(&key);
+			if (!match)
+				continue;
+		}
+
+		if (allowed(&netsrc, tsig, view->matchclients) &&
+		    allowed(&netdst, tsig, view->matchdestinations))
+			break;
+	}
+	return (ISC_TF(view == myview));
+}
+
+/*
+ * Handle an incoming request event from the socket (UDP case)
+ * or tcpmsg (TCP case).
+ */
+static void
+client_request(isc_task_t *task, isc_event_t *event) {
+	ns_client_t *client;
+	isc_socketevent_t *sevent;
+	isc_result_t result;
+	isc_result_t sigresult = ISC_R_SUCCESS;
+	isc_buffer_t *buffer;
+	isc_buffer_t tbuffer;
+	dns_view_t *view;
+	dns_rdataset_t *opt;
+	isc_boolean_t ra; 	/* Recursion available. */
+	isc_netaddr_t netaddr;
+	isc_netaddr_t destaddr;
+	int match;
+	dns_messageid_t id;
+	unsigned int flags;
+	isc_boolean_t notimp;
+
+	REQUIRE(event != NULL);
+	client = event->ev_arg;
+	REQUIRE(NS_CLIENT_VALID(client));
+	REQUIRE(task == client->task);
+
+	INSIST(client->recursionquota == NULL);
+
+	INSIST(client->state ==
+	       TCP_CLIENT(client) ?
+	       NS_CLIENTSTATE_READING :
+	       NS_CLIENTSTATE_READY);
+
+	ns_client_requests++;
+
+	if (event->ev_type == ISC_SOCKEVENT_RECVDONE) {
+		INSIST(!TCP_CLIENT(client));
+		sevent = (isc_socketevent_t *)event;
+		REQUIRE(sevent == client->recvevent);
+		isc_buffer_init(&tbuffer, sevent->region.base, sevent->n);
+		isc_buffer_add(&tbuffer, sevent->n);
+		buffer = &tbuffer;
+		result = sevent->result;
+		if (result == ISC_R_SUCCESS) {
+			client->peeraddr = sevent->address;
+			client->peeraddr_valid = ISC_TRUE;
+		}
+		if ((sevent->attributes & ISC_SOCKEVENTATTR_PKTINFO) != 0) {
+			client->attributes |= NS_CLIENTATTR_PKTINFO;
+			client->pktinfo = sevent->pktinfo;
+		}
+		if ((sevent->attributes & ISC_SOCKEVENTATTR_MULTICAST) != 0)
+			client->attributes |= NS_CLIENTATTR_MULTICAST;
+		client->nrecvs--;
+	} else {
+		INSIST(TCP_CLIENT(client));
+		REQUIRE(event->ev_type == DNS_EVENT_TCPMSG);
+		REQUIRE(event->ev_sender == &client->tcpmsg);
+		buffer = &client->tcpmsg.buffer;
+		result = client->tcpmsg.result;
+		INSIST(client->nreads == 1);
+		/*
+		 * client->peeraddr was set when the connection was accepted.
+		 */
+		client->nreads--;
+	}
+
+	if (exit_check(client))
+		goto cleanup;
+	client->state = client->newstate = NS_CLIENTSTATE_WORKING;
+
+	isc_task_getcurrenttime(task, &client->requesttime);
+	client->now = client->requesttime;
+
+	if (result != ISC_R_SUCCESS) {
+		if (TCP_CLIENT(client)) {
+			ns_client_next(client, result);
+		} else {
+			if  (result != ISC_R_CANCELED)
+				isc_log_write(ns_g_lctx, NS_LOGCATEGORY_CLIENT,
+					      NS_LOGMODULE_CLIENT,
+					      ISC_LOG_ERROR,
+					      "UDP client handler shutting "
+					      "down due to fatal receive "
+					      "error: %s",
+					      isc_result_totext(result));
+			isc_task_shutdown(client->task);
+		}
+		goto cleanup;
+	}
+
+	isc_netaddr_fromsockaddr(&netaddr, &client->peeraddr);
+
+#if NS_CLIENT_DROPPORT
+	if (ns_client_dropport(isc_sockaddr_getport(&client->peeraddr)) ==
+	    DROPPORT_REQUEST) {
+		ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
+			      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(10),
+			      "dropped request: suspicious port");
+		ns_client_next(client, ISC_R_SUCCESS);
+		goto cleanup;
+	}
+#endif
+
+	ns_client_log(client, NS_LOGCATEGORY_CLIENT,
+		      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(3),
+		      "%s request",
+		      TCP_CLIENT(client) ? "TCP" : "UDP");
+
+	/*
+	 * Check the blackhole ACL for UDP only, since TCP is done in
+	 * client_newconn.
+	 */
+	if (!TCP_CLIENT(client)) {
+
+		if (ns_g_server->blackholeacl != NULL &&
+		    dns_acl_match(&netaddr, NULL, ns_g_server->blackholeacl,
+				  &ns_g_server->aclenv,
+				  &match, NULL) == ISC_R_SUCCESS &&
+		    match > 0)
+		{
+			ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
+				      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(10),
+				      "blackholed UDP datagram");
+			ns_client_next(client, ISC_R_SUCCESS);
+			goto cleanup;
+		}
+	}
+
+	/*
+	 * Silently drop multicast requests for the present.
+	 * XXXMPA look at when/if mDNS spec stabilizes.
+	 */
+	if ((client->attributes & NS_CLIENTATTR_MULTICAST) != 0) {
+		ns_client_log(client, NS_LOGCATEGORY_CLIENT,
+			      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(2),
+			      "dropping multicast request");
+		ns_client_next(client, DNS_R_REFUSED);
+		goto cleanup;
+	}
+
+	result = dns_message_peekheader(buffer, &id, &flags);
+	if (result != ISC_R_SUCCESS) {
+		/*
+		 * There isn't enough header to determine whether
+		 * this was a request or a response.  Drop it.
+		 */
+		ns_client_next(client, result);
+		goto cleanup;
+	}
+
+	/*
+	 * The client object handles requests, not responses.
+	 * If this is a UDP response, forward it to the dispatcher.
+	 * If it's a TCP response, discard it here.
+	 */
+	if ((flags & DNS_MESSAGEFLAG_QR) != 0) {
+		if (TCP_CLIENT(client)) {
+			CTRACE("unexpected response");
+			ns_client_next(client, DNS_R_FORMERR);
+			goto cleanup;
+		} else {
+			dns_dispatch_importrecv(client->dispatch, event);
+			ns_client_next(client, ISC_R_SUCCESS);
+			goto cleanup;
+		}
+	}
+
+	/*
+	 * Hash the incoming request here as it is after
+	 * dns_dispatch_importrecv().
+	 */
+	dns_dispatch_hash(&client->now, sizeof(client->now));
+	dns_dispatch_hash(isc_buffer_base(buffer),
+			  isc_buffer_usedlength(buffer));
+
+	/*
+	 * It's a request.  Parse it.
+	 */
+	result = dns_message_parse(client->message, buffer, 0);
+	if (result != ISC_R_SUCCESS) {
+		/*
+		 * Parsing the request failed.  Send a response
+		 * (typically FORMERR or SERVFAIL).
+		 */
+		ns_client_error(client, result);
+		goto cleanup;
+	}
+
+	switch (client->message->opcode) {
+	case dns_opcode_query:
+	case dns_opcode_update:
+	case dns_opcode_notify:
+		notimp = ISC_FALSE;
+		break;
+	case dns_opcode_iquery:
+	default:
+		notimp = ISC_TRUE;
+		break;
+	}
+
+	client->message->rcode = dns_rcode_noerror;
+
+	/* RFC1123 section 6.1.3.2 */
+	if ((client->attributes & NS_CLIENTATTR_MULTICAST) != 0)
+		client->message->flags &= ~DNS_MESSAGEFLAG_RD;
+
+	/*
+	 * Deal with EDNS.
+	 */
+	opt = dns_message_getopt(client->message);
+	if (opt != NULL) {
+		/*
+		 * Set the client's UDP buffer size.
+		 */
+		client->udpsize = opt->rdclass;
+
+		/*
+		 * If the requested UDP buffer size is less than 512,
+		 * ignore it and use 512.
+		 */
+		if (client->udpsize < 512)
+			client->udpsize = 512;
+
+		/*
+		 * Get the flags out of the OPT record.
+		 */
+		client->extflags = (isc_uint16_t)(opt->ttl & 0xFFFF);
+
+		/*
+		 * Do we understand this version of EDNS?
+		 *
+		 * XXXRTH need library support for this!
+		 */
+		client->ednsversion = (opt->ttl & 0x00FF0000) >> 16;
+		if (client->ednsversion > 0) {
+			result = client_addopt(client);
+			if (result == ISC_R_SUCCESS)
+				result = DNS_R_BADVERS;
+			ns_client_error(client, result);
+			goto cleanup;
+		}
+		/*
+		 * Create an OPT for our reply.
+		 */
+		result = client_addopt(client);
+		if (result != ISC_R_SUCCESS) {
+			ns_client_error(client, result);
+			goto cleanup;
+		}
+	}
+
+	if (client->message->rdclass == 0) {
+		ns_client_log(client, NS_LOGCATEGORY_CLIENT,
+			      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(1),
+			      "message class could not be determined");
+		ns_client_dumpmessage(client,
+				      "message class could not be determined");
+		ns_client_error(client, notimp ? DNS_R_NOTIMP : DNS_R_FORMERR);
+		goto cleanup;
+	}
+
+	/*
+	 * Determine the destination address.  If the receiving interface is
+	 * bound to a specific address, we simply use it regardless of the
+	 * address family.  All IPv4 queries should fall into this case.
+	 * Otherwise, if this is a TCP query, get the address from the
+	 * receiving socket (this needs a system call and can be heavy).
+	 * For IPv6 UDP queries, we get this from the pktinfo structure (if
+	 * supported).
+	 * If all the attempts fail (this can happen due to memory shortage,
+	 * etc), we regard this as an error for safety. 
+	 */
+	if ((client->interface->flags & NS_INTERFACEFLAG_ANYADDR) == 0)
+		isc_netaddr_fromsockaddr(&destaddr, &client->interface->addr);
+	else {
+		result = ISC_R_FAILURE;
+
+		if (TCP_CLIENT(client)) {
+			isc_sockaddr_t destsockaddr;
+
+			result = isc_socket_getsockname(client->tcpsocket,
+							&destsockaddr);
+			if (result == ISC_R_SUCCESS)
+				isc_netaddr_fromsockaddr(&destaddr,
+							 &destsockaddr);
+		}
+		if (result != ISC_R_SUCCESS &&
+		    client->interface->addr.type.sa.sa_family == AF_INET6 &&
+		    (client->attributes & NS_CLIENTATTR_PKTINFO) != 0) {
+			isc_uint32_t zone = 0;
+
+			/*
+			 * XXXJT technically, we should convert the receiving
+			 * interface ID to a proper scope zone ID.  However,
+			 * due to the fact there is no standard API for this,
+			 * we only handle link-local addresses and use the
+			 * interface index as link ID.  Despite the assumption,
+			 * it should cover most typical cases.
+			 */
+			if (IN6_IS_ADDR_LINKLOCAL(&client->pktinfo.ipi6_addr))
+				zone = (isc_uint32_t)client->pktinfo.ipi6_ifindex;
+
+			isc_netaddr_fromin6(&destaddr,
+					    &client->pktinfo.ipi6_addr);
+			isc_netaddr_setzone(&destaddr, zone);
+			result = ISC_R_SUCCESS;
+		}
+		if (result != ISC_R_SUCCESS) {
+			UNEXPECTED_ERROR(__FILE__, __LINE__,
+					 "failed to get request's "
+					 "destination: %s",
+					 isc_result_totext(result));
+			ns_client_next(client, ISC_R_SUCCESS);
+			goto cleanup;
+		}
+	}
+
+	/*
+	 * Find a view that matches the client's source address.
+	 */
+	for (view = ISC_LIST_HEAD(ns_g_server->viewlist);
+	     view != NULL;
+	     view = ISC_LIST_NEXT(view, link)) {
+		if (client->message->rdclass == view->rdclass ||
+		    client->message->rdclass == dns_rdataclass_any)
+		{
+			dns_name_t *tsig = NULL;
+			sigresult = dns_message_rechecksig(client->message,
+							   view);
+			if (sigresult == ISC_R_SUCCESS)
+				tsig = client->message->tsigname;
+				
+			if (allowed(&netaddr, tsig, view->matchclients) &&
+			    allowed(&destaddr, tsig, view->matchdestinations) &&
+			    !((client->message->flags & DNS_MESSAGEFLAG_RD)
+			      == 0 && view->matchrecursiveonly))
+			{
+				dns_view_attach(view, &client->view);
+				break;
+			}
+		}
+	}
+
+	if (view == NULL) {
+		char classname[DNS_RDATACLASS_FORMATSIZE];
+
+		/*
+		 * Do a dummy TSIG verification attempt so that the
+		 * response will have a TSIG if the query did, as
+		 * required by RFC2845.
+		 */
+		isc_buffer_t b;
+		isc_region_t *r;
+
+		dns_message_resetsig(client->message);
+
+		r = dns_message_getrawmessage(client->message);
+		isc_buffer_init(&b, r->base, r->length);
+		isc_buffer_add(&b, r->length);
+		(void)dns_tsig_verify(&b, client->message, NULL, NULL);
+
+		dns_rdataclass_format(client->message->rdclass, classname,
+				      sizeof(classname));
+		ns_client_log(client, NS_LOGCATEGORY_CLIENT,
+			      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(1),
+			      "no matching view in class '%s'", classname);
+		ns_client_dumpmessage(client, "no matching view in class");
+		ns_client_error(client, notimp ? DNS_R_NOTIMP : DNS_R_REFUSED);
+		goto cleanup;
+	}
+
+	ns_client_log(client, NS_LOGCATEGORY_CLIENT,
+		      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(5),
+		      "using view '%s'", view->name);
+
+	/*
+	 * Check for a signature.  We log bad signatures regardless of
+	 * whether they ultimately cause the request to be rejected or
+	 * not.  We do not log the lack of a signature unless we are
+	 * debugging.
+	 */
+	client->signer = NULL;
+	dns_name_init(&client->signername, NULL);
+	result = dns_message_signer(client->message, &client->signername);
+	if (result == ISC_R_SUCCESS) {
+		ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
+			      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(3),
+			      "request has valid signature");
+		client->signer = &client->signername;
+	} else if (result == ISC_R_NOTFOUND) {
+		ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
+			      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(3),
+			      "request is not signed");
+	} else if (result == DNS_R_NOIDENTITY) {
+		ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
+			      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(3),
+			      "request is signed by a nonauthoritative key");
+	} else {
+		char tsigrcode[64];
+		isc_buffer_t b;
+		dns_name_t *name = NULL;
+		dns_rcode_t status;
+		isc_result_t tresult;
+
+		/* There is a signature, but it is bad. */
+		if (dns_message_gettsig(client->message, &name) != NULL) {
+			char namebuf[DNS_NAME_FORMATSIZE];
+			dns_name_format(name, namebuf, sizeof(namebuf));
+			status = client->message->tsigstatus;
+			isc_buffer_init(&b, tsigrcode, sizeof(tsigrcode) - 1);
+			tresult = dns_tsigrcode_totext(status, &b);
+			INSIST(tresult == ISC_R_SUCCESS);
+			tsigrcode[isc_buffer_usedlength(&b)] = '\0';
+			ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
+				      NS_LOGMODULE_CLIENT, ISC_LOG_ERROR,
+				      "request has invalid signature: "
+				      "TSIG %s: %s (%s)", namebuf,
+				      isc_result_totext(result), tsigrcode);
+		} else {
+			status = client->message->sig0status;
+			isc_buffer_init(&b, tsigrcode, sizeof(tsigrcode) - 1);
+			tresult = dns_tsigrcode_totext(status, &b);
+			INSIST(tresult == ISC_R_SUCCESS);
+			tsigrcode[isc_buffer_usedlength(&b)] = '\0';
+			ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
+				      NS_LOGMODULE_CLIENT, ISC_LOG_ERROR,
+				      "request has invalid signature: %s (%s)",
+				      isc_result_totext(result), tsigrcode);
+		}
+		/*
+		 * Accept update messages signed by unknown keys so that
+		 * update forwarding works transparently through slaves
+		 * that don't have all the same keys as the master.
+		 */
+		if (!(client->message->tsigstatus == dns_tsigerror_badkey &&
+		      client->message->opcode == dns_opcode_update)) {
+			ns_client_error(client, sigresult);
+			goto cleanup;
+		}
+	}
+
+	/*
+	 * Decide whether recursive service is available to this client.
+	 * We do this here rather than in the query code so that we can
+	 * set the RA bit correctly on all kinds of responses, not just
+	 * responses to ordinary queries.  Note if you can't query the
+	 * cache there is no point in setting RA.
+	 */
+	ra = ISC_FALSE;
+	if (client->view->resolver != NULL &&
+	    client->view->recursion == ISC_TRUE &&
+	    ns_client_checkaclsilent(client, client->view->recursionacl,
+				     ISC_TRUE) == ISC_R_SUCCESS &&
+	    ns_client_checkaclsilent(client, client->view->queryacl,
+				     ISC_TRUE) == ISC_R_SUCCESS)
+		ra = ISC_TRUE;
+
+	if (ra == ISC_TRUE)
+		client->attributes |= NS_CLIENTATTR_RA;
+
+	ns_client_log(client, DNS_LOGCATEGORY_SECURITY, NS_LOGMODULE_CLIENT,
+		      ISC_LOG_DEBUG(3), ra ? "recursion available" :
+		      			     "recursion not available");
+
+	/*
+	 * Adjust maximum UDP response size for this client.
+	 */
+	if (client->udpsize > 512) {
+		dns_peer_t *peer = NULL;
+		isc_uint16_t udpsize = view->maxudp;
+		(void) dns_peerlist_peerbyaddr(view->peers, &netaddr, &peer);
+		if (peer != NULL)
+			dns_peer_getmaxudp(peer, &udpsize);
+		if (client->udpsize > udpsize)
+			client->udpsize = udpsize;
+	}
+
+	/*
+	 * Dispatch the request.
+	 */
+	switch (client->message->opcode) {
+	case dns_opcode_query:
+		CTRACE("query");
+		ns_query_start(client);
+		break;
+	case dns_opcode_update:
+		CTRACE("update");
+		ns_client_settimeout(client, 60);
+		ns_update_start(client, sigresult);
+		break;
+	case dns_opcode_notify:
+		CTRACE("notify");
+		ns_client_settimeout(client, 60);
+		ns_notify_start(client);
+		break;
+	case dns_opcode_iquery:
+		CTRACE("iquery");
+		ns_client_error(client, DNS_R_NOTIMP);
+		break;
+	default:
+		CTRACE("unknown opcode");
+		ns_client_error(client, DNS_R_NOTIMP);
+	}
+
+ cleanup:
+	return;
+}
+
+static void
+client_timeout(isc_task_t *task, isc_event_t *event) {
+	ns_client_t *client;
+
+	REQUIRE(event != NULL);
+	REQUIRE(event->ev_type == ISC_TIMEREVENT_LIFE ||
+		event->ev_type == ISC_TIMEREVENT_IDLE);
+	client = event->ev_arg;
+	REQUIRE(NS_CLIENT_VALID(client));
+	REQUIRE(task == client->task);
+	REQUIRE(client->timer != NULL);
+
+	UNUSED(task);
+
+	CTRACE("timeout");
+
+	isc_event_free(&event);
+
+	if (client->shutdown != NULL) {
+		(client->shutdown)(client->shutdown_arg, ISC_R_TIMEDOUT);
+		client->shutdown = NULL;
+		client->shutdown_arg = NULL;
+	}
+
+	if (client->newstate > NS_CLIENTSTATE_READY)
+		client->newstate = NS_CLIENTSTATE_READY;
+	(void)exit_check(client);
+}
+
+static isc_result_t
+get_clientmctx(ns_clientmgr_t *manager, isc_mem_t **mctxp) {
+	isc_mem_t *clientmctx;
+#if NMCTXS > 0
+	isc_result_t result;
+#endif
+
+	/*
+	 * Caller must be holding the manager lock.
+	 */
+#if NMCTXS > 0
+	INSIST(manager->nextmctx < NMCTXS);
+	clientmctx = manager->mctxpool[manager->nextmctx];
+	if (clientmctx == NULL) {
+		result = isc_mem_create(0, 0, &clientmctx);
+		if (result != ISC_R_SUCCESS)
+			return (result);
+
+		manager->mctxpool[manager->nextmctx] = clientmctx;
+		manager->nextmctx++;
+		if (manager->nextmctx == NMCTXS)
+			manager->nextmctx = 0;
+	}
+#else
+	clientmctx = manager->mctx;
+#endif
+
+	isc_mem_attach(clientmctx, mctxp);
+
+	return (ISC_R_SUCCESS);
+}
+
+static isc_result_t
+client_create(ns_clientmgr_t *manager, ns_client_t **clientp) {
+	ns_client_t *client;
+	isc_result_t result;
+	isc_mem_t *mctx = NULL;
+
+	/*
+	 * Caller must be holding the manager lock.
+	 *
+	 * Note: creating a client does not add the client to the
+	 * manager's client list or set the client's manager pointer.
+	 * The caller is responsible for that.
+	 */
+
+	REQUIRE(clientp != NULL && *clientp == NULL);
+
+	result = get_clientmctx(manager, &mctx);
+	if (result != ISC_R_SUCCESS)
+		return (result);
+
+	client = isc_mem_get(mctx, sizeof(*client));
+	if (client == NULL) {
+		isc_mem_detach(&mctx);
+		return (ISC_R_NOMEMORY);
+	}
+	client->mctx = mctx;
+
+	client->task = NULL;
+	result = isc_task_create(manager->taskmgr, 0, &client->task);
+	if (result != ISC_R_SUCCESS)
+		goto cleanup_client;
+	isc_task_setname(client->task, "client", client);
+
+	client->timer = NULL;
+	result = isc_timer_create(manager->timermgr, isc_timertype_inactive,
+				  NULL, NULL, client->task, client_timeout,
+				  client, &client->timer);
+	if (result != ISC_R_SUCCESS)
+		goto cleanup_task;
+	client->timerset = ISC_FALSE;
+
+	client->message = NULL;
+	result = dns_message_create(client->mctx, DNS_MESSAGE_INTENTPARSE,
+				    &client->message);
+	if (result != ISC_R_SUCCESS)
+		goto cleanup_timer;
+
+	/* XXXRTH  Hardwired constants */
+
+	client->sendevent = (isc_socketevent_t *)
+			    isc_event_allocate(client->mctx, client,
+					       ISC_SOCKEVENT_SENDDONE,
+					       client_senddone, client,
+					       sizeof(isc_socketevent_t));
+	if (client->sendevent == NULL) {
+		result = ISC_R_NOMEMORY;
+		goto cleanup_message;
+	}
+
+	client->recvbuf = isc_mem_get(client->mctx, RECV_BUFFER_SIZE);
+	if  (client->recvbuf == NULL) {
+		result = ISC_R_NOMEMORY;
+		goto cleanup_sendevent;
+	}
+
+	client->recvevent = (isc_socketevent_t *)
+			    isc_event_allocate(client->mctx, client,
+					       ISC_SOCKEVENT_RECVDONE,
+					       client_request, client,
+					       sizeof(isc_socketevent_t));
+	if (client->recvevent == NULL) {
+		result = ISC_R_NOMEMORY;
+		goto cleanup_recvbuf;
+	}
+
+	client->magic = NS_CLIENT_MAGIC;
+	client->manager = NULL;
+	client->state = NS_CLIENTSTATE_INACTIVE;
+	client->newstate = NS_CLIENTSTATE_MAX;
+	client->naccepts = 0;
+	client->nreads = 0;
+	client->nsends = 0;
+	client->nrecvs = 0;
+	client->nupdates = 0;
+	client->nctls = 0;
+	client->references = 0;
+	client->attributes = 0;
+	client->view = NULL;
+	client->dispatch = NULL;
+	client->udpsocket = NULL;
+	client->tcplistener = NULL;
+	client->tcpsocket = NULL;
+	client->tcpmsg_valid = ISC_FALSE;
+	client->tcpbuf = NULL;
+	client->opt = NULL;
+	client->udpsize = 512;
+	client->extflags = 0;
+	client->ednsversion = -1;
+	client->next = NULL;
+	client->shutdown = NULL;
+	client->shutdown_arg = NULL;
+	dns_name_init(&client->signername, NULL);
+	client->mortal = ISC_FALSE;
+	client->tcpquota = NULL;
+	client->recursionquota = NULL;
+	client->interface = NULL;
+	client->peeraddr_valid = ISC_FALSE;
+	ISC_EVENT_INIT(&client->ctlevent, sizeof(client->ctlevent), 0, NULL,
+		       NS_EVENT_CLIENTCONTROL, client_start, client, client,
+		       NULL, NULL);
+	/*
+	 * Initialize FORMERR cache to sentinel value that will not match
+	 * any actual FORMERR response.
+	 */
+	isc_sockaddr_any(&client->formerrcache.addr);
+	client->formerrcache.time = 0;
+	client->formerrcache.id = 0;
+	ISC_LINK_INIT(client, link);
+	client->list = NULL;
+
+	/*
+	 * We call the init routines for the various kinds of client here,
+	 * after we have created an otherwise valid client, because some
+	 * of them call routines that REQUIRE(NS_CLIENT_VALID(client)).
+	 */
+	result = ns_query_init(client);
+	if (result != ISC_R_SUCCESS)
+		goto cleanup_recvevent;
+
+	result = isc_task_onshutdown(client->task, client_shutdown, client);
+	if (result != ISC_R_SUCCESS)
+		goto cleanup_query;
+
+	CTRACE("create");
+
+	*clientp = client;
+
+	return (ISC_R_SUCCESS);
+
+ cleanup_query:
+	ns_query_free(client);
+
+ cleanup_recvevent:
+	isc_event_free((isc_event_t **)&client->recvevent);
+
+ cleanup_recvbuf:
+	isc_mem_put(client->mctx, client->recvbuf, RECV_BUFFER_SIZE);
+
+ cleanup_sendevent:
+	isc_event_free((isc_event_t **)&client->sendevent);
+
+	client->magic = 0;
+
+ cleanup_message:
+	dns_message_destroy(&client->message);
+
+ cleanup_timer:
+	isc_timer_detach(&client->timer);
+
+ cleanup_task:
+	isc_task_detach(&client->task);
+
+ cleanup_client:
+	isc_mem_putanddetach(&client->mctx, client, sizeof(*client));
+
+	return (result);
+}
+
+static void
+client_read(ns_client_t *client) {
+	isc_result_t result;
+
+	CTRACE("read");
+
+	result = dns_tcpmsg_readmessage(&client->tcpmsg, client->task,
+					client_request, client);
+	if (result != ISC_R_SUCCESS)
+		goto fail;
+
+	/*
+	 * Set a timeout to limit the amount of time we will wait
+	 * for a request on this TCP connection.
+	 */
+	ns_client_settimeout(client, 30);
+
+	client->state = client->newstate = NS_CLIENTSTATE_READING;
+	INSIST(client->nreads == 0);
+	INSIST(client->recursionquota == NULL);
+	client->nreads++;
+
+	return;
+ fail:
+	ns_client_next(client, result);
+}
+
+static void
+client_newconn(isc_task_t *task, isc_event_t *event) {
+	ns_client_t *client = event->ev_arg;
+	isc_socket_newconnev_t *nevent = (isc_socket_newconnev_t *)event;
+	isc_result_t result;
+
+	REQUIRE(event->ev_type == ISC_SOCKEVENT_NEWCONN);
+	REQUIRE(NS_CLIENT_VALID(client));
+	REQUIRE(client->task == task);
+
+	UNUSED(task);
+
+	INSIST(client->state == NS_CLIENTSTATE_READY);
+
+	INSIST(client->naccepts == 1);
+	client->naccepts--;
+
+	LOCK(&client->interface->lock);
+	INSIST(client->interface->ntcpcurrent > 0);
+	client->interface->ntcpcurrent--;
+	UNLOCK(&client->interface->lock);
+
+	/*
+	 * We must take ownership of the new socket before the exit
+	 * check to make sure it gets destroyed if we decide to exit.
+	 */
+	if (nevent->result == ISC_R_SUCCESS) {
+		client->tcpsocket = nevent->newsocket;
+		client->state = NS_CLIENTSTATE_READING;
+		INSIST(client->recursionquota == NULL);
+
+		(void)isc_socket_getpeername(client->tcpsocket,
+					     &client->peeraddr);
+		client->peeraddr_valid = ISC_TRUE;
+		ns_client_log(client, NS_LOGCATEGORY_CLIENT,
+			   NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(3),
+			   "new TCP connection");
+	} else {
+		/*
+		 * XXXRTH  What should we do?  We're trying to accept but
+		 *         it didn't work.  If we just give up, then TCP
+		 *	   service may eventually stop.
+		 *
+		 *	   For now, we just go idle.
+		 *
+		 *	   Going idle is probably the right thing if the
+		 *	   I/O was canceled.
+		 */
+		ns_client_log(client, NS_LOGCATEGORY_CLIENT,
+			      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(3),
+			      "accept failed: %s",
+			      isc_result_totext(nevent->result));
+	}
+
+	if (exit_check(client))
+		goto freeevent;
+
+	if (nevent->result == ISC_R_SUCCESS) {
+		int match;
+		isc_netaddr_t netaddr;
+
+		isc_netaddr_fromsockaddr(&netaddr, &client->peeraddr);
+
+		if (ns_g_server->blackholeacl != NULL &&
+		    dns_acl_match(&netaddr, NULL,
+			    	  ns_g_server->blackholeacl,
+				  &ns_g_server->aclenv,
+				  &match, NULL) == ISC_R_SUCCESS &&
+		    match > 0)
+		{
+			ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
+				      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(10),
+				      "blackholed connection attempt");
+			client->newstate = NS_CLIENTSTATE_READY;
+			(void)exit_check(client);
+			goto freeevent;
+		}
+
+		INSIST(client->tcpmsg_valid == ISC_FALSE);
+		dns_tcpmsg_init(client->mctx, client->tcpsocket,
+				&client->tcpmsg);
+		client->tcpmsg_valid = ISC_TRUE;
+
+		/*
+		 * Let a new client take our place immediately, before
+		 * we wait for a request packet.  If we don't,
+		 * telnetting to port 53 (once per CPU) will
+		 * deny service to legititmate TCP clients.
+		 */
+		result = isc_quota_attach(&ns_g_server->tcpquota,
+					  &client->tcpquota);
+		if (result == ISC_R_SUCCESS)
+			result = ns_client_replace(client);
+		if (result != ISC_R_SUCCESS) {
+			ns_client_log(client, NS_LOGCATEGORY_CLIENT,
+				      NS_LOGMODULE_CLIENT, ISC_LOG_WARNING,
+				      "no more TCP clients: %s",
+				      isc_result_totext(result));
+		}
+
+		client_read(client);
+	}
+
+ freeevent:
+	isc_event_free(&event);
+}
+
+static void
+client_accept(ns_client_t *client) {
+	isc_result_t result;
+
+	CTRACE("accept");
+
+	result = isc_socket_accept(client->tcplistener, client->task,
+				   client_newconn, client);
+	if (result != ISC_R_SUCCESS) {
+		UNEXPECTED_ERROR(__FILE__, __LINE__,
+				 "isc_socket_accept() failed: %s",
+				 isc_result_totext(result));
+		/*
+		 * XXXRTH  What should we do?  We're trying to accept but
+		 *         it didn't work.  If we just give up, then TCP
+		 *	   service may eventually stop.
+		 *
+		 *	   For now, we just go idle.
+		 */
+		return;
+	}
+	INSIST(client->naccepts == 0);
+	client->naccepts++;
+	LOCK(&client->interface->lock);
+	client->interface->ntcpcurrent++;
+	UNLOCK(&client->interface->lock);
+}
+
+static void
+client_udprecv(ns_client_t *client) {
+	isc_result_t result;
+	isc_region_t r;
+
+	CTRACE("udprecv");
+
+	r.base = client->recvbuf;
+	r.length = RECV_BUFFER_SIZE;
+	result = isc_socket_recv2(client->udpsocket, &r, 1,
+				  client->task, client->recvevent, 0);
+	if (result != ISC_R_SUCCESS) {
+		UNEXPECTED_ERROR(__FILE__, __LINE__,
+				 "isc_socket_recv2() failed: %s",
+				 isc_result_totext(result));
+		/*
+		 * This cannot happen in the current implementation, since
+		 * isc_socket_recv2() cannot fail if flags == 0.
+		 *
+		 * If this does fail, we just go idle.
+		 */
+		return;
+	}
+	INSIST(client->nrecvs == 0);
+	client->nrecvs++;
+}
+
+void
+ns_client_attach(ns_client_t *source, ns_client_t **targetp) {
+	REQUIRE(NS_CLIENT_VALID(source));
+	REQUIRE(targetp != NULL && *targetp == NULL);
+
+	source->references++;
+	ns_client_log(source, NS_LOGCATEGORY_CLIENT,
+		      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(10),
+		      "ns_client_attach: ref = %d", source->references);
+	*targetp = source;
+}
+
+void
+ns_client_detach(ns_client_t **clientp) {
+	ns_client_t *client = *clientp;
+
+	client->references--;
+	INSIST(client->references >= 0);
+	*clientp = NULL;
+	ns_client_log(client, NS_LOGCATEGORY_CLIENT,
+		      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(10),
+		      "ns_client_detach: ref = %d", client->references);
+	(void)exit_check(client);
+}
+
+isc_boolean_t
+ns_client_shuttingdown(ns_client_t *client) {
+	return (ISC_TF(client->newstate == NS_CLIENTSTATE_FREED));
+}
+
+isc_result_t
+ns_client_replace(ns_client_t *client) {
+	isc_result_t result;
+
+	CTRACE("replace");
+
+	result = ns_clientmgr_createclients(client->manager,
+					    1, client->interface,
+					    (TCP_CLIENT(client) ?
+					     ISC_TRUE : ISC_FALSE));
+	if (result != ISC_R_SUCCESS)
+		return (result);
+
+	/*
+	 * The responsibility for listening for new requests is hereby
+	 * transferred to the new client.  Therefore, the old client
+	 * should refrain from listening for any more requests.
+	 */
+	client->mortal = ISC_TRUE;
+
+	return (ISC_R_SUCCESS);
+}
+
+/***
+ *** Client Manager
+ ***/
+
+static void
+clientmgr_destroy(ns_clientmgr_t *manager) {
+#if NMCTXS > 0
+	int i;
+#endif
+
+	REQUIRE(ISC_LIST_EMPTY(manager->active));
+	REQUIRE(ISC_LIST_EMPTY(manager->inactive));
+	REQUIRE(ISC_LIST_EMPTY(manager->recursing));
+
+	MTRACE("clientmgr_destroy");
+
+#if NMCTXS > 0
+	for (i = 0; i < NMCTXS; i++) {
+		if (manager->mctxpool[i] != NULL)
+			isc_mem_detach(&manager->mctxpool[i]);
+	}
+#endif
+
+	DESTROYLOCK(&manager->lock);
+	manager->magic = 0;
+	isc_mem_put(manager->mctx, manager, sizeof(*manager));
+}
+
+isc_result_t
+ns_clientmgr_create(isc_mem_t *mctx, isc_taskmgr_t *taskmgr,
+		    isc_timermgr_t *timermgr, ns_clientmgr_t **managerp)
+{
+	ns_clientmgr_t *manager;
+	isc_result_t result;
+#if NMCTXS > 0
+	int i;
+#endif
+
+	manager = isc_mem_get(mctx, sizeof(*manager));
+	if (manager == NULL)
+		return (ISC_R_NOMEMORY);
+
+	result = isc_mutex_init(&manager->lock);
+	if (result != ISC_R_SUCCESS)
+		goto cleanup_manager;
+
+	manager->mctx = mctx;
+	manager->taskmgr = taskmgr;
+	manager->timermgr = timermgr;
+	manager->exiting = ISC_FALSE;
+	ISC_LIST_INIT(manager->active);
+	ISC_LIST_INIT(manager->inactive);
+	ISC_LIST_INIT(manager->recursing);
+#if NMCTXS > 0
+	manager->nextmctx = 0;
+	for (i = 0; i < NMCTXS; i++)
+		manager->mctxpool[i] = NULL; /* will be created on-demand */
+#endif
+	manager->magic = MANAGER_MAGIC;
+
+	MTRACE("create");
+
+	*managerp = manager;
+
+	return (ISC_R_SUCCESS);
+
+ cleanup_manager:
+	isc_mem_put(manager->mctx, manager, sizeof(*manager));
+
+	return (result);
+}
+
+void
+ns_clientmgr_destroy(ns_clientmgr_t **managerp) {
+	ns_clientmgr_t *manager;
+	ns_client_t *client;
+	isc_boolean_t need_destroy = ISC_FALSE;
+
+	REQUIRE(managerp != NULL);
+	manager = *managerp;
+	REQUIRE(VALID_MANAGER(manager));
+
+	MTRACE("destroy");
+
+	LOCK(&manager->lock);
+
+	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))
+		isc_task_shutdown(client->task);
+
+	for (client = ISC_LIST_HEAD(manager->inactive);
+	     client != NULL;
+	     client = ISC_LIST_NEXT(client, link))
+		isc_task_shutdown(client->task);
+
+	if (ISC_LIST_EMPTY(manager->active) &&
+	    ISC_LIST_EMPTY(manager->inactive) &&
+	    ISC_LIST_EMPTY(manager->recursing))
+		need_destroy = ISC_TRUE;
+
+	UNLOCK(&manager->lock);
+
+	if (need_destroy)
+		clientmgr_destroy(manager);
+
+	*managerp = NULL;
+}
+
+isc_result_t
+ns_clientmgr_createclients(ns_clientmgr_t *manager, unsigned int n,
+			   ns_interface_t *ifp, isc_boolean_t tcp)
+{
+	isc_result_t result = ISC_R_SUCCESS;
+	unsigned int i;
+	ns_client_t *client;
+
+	REQUIRE(VALID_MANAGER(manager));
+	REQUIRE(n > 0);
+
+	MTRACE("createclients");
+
+	/*
+	 * We MUST lock the manager lock for the entire client creation
+	 * process.  If we didn't do this, then a client could get a
+	 * shutdown event and disappear out from under us.
+	 */
+
+	LOCK(&manager->lock);
+
+	for (i = 0; i < n; i++) {
+		isc_event_t *ev;
+		/*
+		 * Allocate a client.  First try to get a recycled one;
+		 * if that fails, make a new one.
+		 */
+		client = ISC_LIST_HEAD(manager->inactive);
+		if (client != NULL) {
+			MTRACE("recycle");
+			ISC_LIST_UNLINK(manager->inactive, client, link);
+			client->list = NULL;
+		} else {
+			MTRACE("create new");
+			result = client_create(manager, &client);
+			if (result != ISC_R_SUCCESS)
+				break;
+		}
+
+		ns_interface_attach(ifp, &client->interface);
+		client->state = NS_CLIENTSTATE_READY;
+		INSIST(client->recursionquota == NULL);
+
+		if (tcp) {
+			client->attributes |= NS_CLIENTATTR_TCP;
+			isc_socket_attach(ifp->tcpsocket,
+					  &client->tcplistener);
+		} else {
+			isc_socket_t *sock;
+
+			dns_dispatch_attach(ifp->udpdispatch,
+					    &client->dispatch);
+			sock = dns_dispatch_getsocket(client->dispatch);
+			isc_socket_attach(sock, &client->udpsocket);
+		}
+		client->manager = manager;
+		ISC_LIST_APPEND(manager->active, client, link);
+		client->list = &manager->active;
+
+		INSIST(client->nctls == 0);
+		client->nctls++;
+		ev = &client->ctlevent;
+		isc_task_send(client->task, &ev);
+	}
+	if (i != 0) {
+		/*
+		 * We managed to create at least one client, so we
+		 * declare victory.
+		 */
+		result = ISC_R_SUCCESS;
+	}
+
+	UNLOCK(&manager->lock);
+
+	return (result);
+}
+
+isc_sockaddr_t *
+ns_client_getsockaddr(ns_client_t *client) {
+	return (&client->peeraddr);
+}
+
+isc_result_t
+ns_client_checkaclsilent(ns_client_t *client, dns_acl_t *acl,
+			 isc_boolean_t default_allow)
+{
+	isc_result_t result;
+	int match;
+	isc_netaddr_t netaddr;
+
+	if (acl == NULL) {
+		if (default_allow)
+			goto allow;
+		else
+			goto deny;
+	}
+
+	isc_netaddr_fromsockaddr(&netaddr, &client->peeraddr);
+
+	result = dns_acl_match(&netaddr, client->signer, acl,
+			       &ns_g_server->aclenv,
+			       &match, NULL);
+	if (result != ISC_R_SUCCESS)
+		goto deny; /* Internal error, already logged. */
+	if (match > 0)
+		goto allow;
+	goto deny; /* Negative match or no match. */
+
+ allow:
+	return (ISC_R_SUCCESS);
+
+ deny:
+	return (DNS_R_REFUSED);
+}
+
+isc_result_t
+ns_client_checkacl(ns_client_t *client,
+		   const char *opname, dns_acl_t *acl,
+		   isc_boolean_t default_allow, int log_level)
+{
+	isc_result_t result =
+		ns_client_checkaclsilent(client, acl, default_allow);
+
+	if (result == ISC_R_SUCCESS) 
+		ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
+			      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(3),
+			      "%s approved", opname);
+	else
+		ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
+			      NS_LOGMODULE_CLIENT,
+			      log_level, "%s denied", opname);
+	return (result);
+}
+
+static void
+ns_client_name(ns_client_t *client, char *peerbuf, size_t len) {
+	if (client->peeraddr_valid)
+		isc_sockaddr_format(&client->peeraddr, peerbuf, len);
+	else
+		snprintf(peerbuf, len, "@%p", client);
+}
+
+void
+ns_client_logv(ns_client_t *client, isc_logcategory_t *category,
+	   isc_logmodule_t *module, int level, const char *fmt, va_list ap)
+{
+	char msgbuf[2048];
+	char peerbuf[ISC_SOCKADDR_FORMATSIZE];
+	const char *name = "";
+	const char *sep = "";
+
+	vsnprintf(msgbuf, sizeof(msgbuf), fmt, ap);
+	ns_client_name(client, peerbuf, sizeof(peerbuf));
+	if (client->view != NULL && strcmp(client->view->name, "_bind") != 0 &&
+	    strcmp(client->view->name, "_default") != 0) {
+		name = client->view->name;
+		sep = ": view ";
+	}
+
+	isc_log_write(ns_g_lctx, category, module, level,
+		      "client %s%s%s: %s", peerbuf, sep, name, msgbuf);
+}
+
+void
+ns_client_log(ns_client_t *client, isc_logcategory_t *category,
+	   isc_logmodule_t *module, int level, const char *fmt, ...)
+{
+	va_list ap;
+
+	if (! isc_log_wouldlog(ns_g_lctx, level))
+		return;
+
+	va_start(ap, fmt);
+	ns_client_logv(client, category, module, level, fmt, ap);
+	va_end(ap);
+}
+
+void
+ns_client_aclmsg(const char *msg, dns_name_t *name, dns_rdatatype_t type,
+		 dns_rdataclass_t rdclass, char *buf, size_t len) 
+{
+        char namebuf[DNS_NAME_FORMATSIZE];
+        char typebuf[DNS_RDATATYPE_FORMATSIZE];
+        char classbuf[DNS_RDATACLASS_FORMATSIZE];
+
+        dns_name_format(name, namebuf, sizeof(namebuf));
+        dns_rdatatype_format(type, typebuf, sizeof(typebuf));
+        dns_rdataclass_format(rdclass, classbuf, sizeof(classbuf));
+        (void)snprintf(buf, len, "%s '%s/%s/%s'", msg, namebuf, typebuf,
+		       classbuf);
+}
+
+static void
+ns_client_dumpmessage(ns_client_t *client, const char *reason) {
+	isc_buffer_t buffer;
+	char *buf = NULL;
+	int len = 1024;
+	isc_result_t result;
+
+	/*
+	 * Note that these are multiline debug messages.  We want a newline
+	 * to appear in the log after each message.
+	 */
+
+	do {
+		buf = isc_mem_get(client->mctx, len);
+		if (buf == NULL)
+			break;
+		isc_buffer_init(&buffer, buf, len);
+		result = dns_message_totext(client->message,
+					    &dns_master_style_debug,
+					    0, &buffer);
+		if (result == ISC_R_NOSPACE) {
+			isc_mem_put(client->mctx, buf, len);
+			len += 1024;
+		} else if (result == ISC_R_SUCCESS)
+		        ns_client_log(client, NS_LOGCATEGORY_UNMATCHED,
+				      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(1),
+				      "%s\n%.*s", reason,
+				       (int)isc_buffer_usedlength(&buffer),
+				       buf);
+	} while (result == ISC_R_NOSPACE);
+
+	if (buf != NULL)
+		isc_mem_put(client->mctx, buf, len);
+}
+
+void
+ns_client_dumprecursing(FILE *f, ns_clientmgr_t *manager) {
+	ns_client_t *client;
+	char namebuf[DNS_NAME_FORMATSIZE];
+	char peerbuf[ISC_SOCKADDR_FORMATSIZE];
+	const char *name;
+	const char *sep;
+
+	REQUIRE(VALID_MANAGER(manager));
+	      
+	LOCK(&manager->lock);
+	client = ISC_LIST_HEAD(manager->recursing);
+	while (client != NULL) {
+		ns_client_name(client, peerbuf, sizeof(peerbuf));
+		if (client->view != NULL &&
+		    strcmp(client->view->name, "_bind") != 0 &&
+		    strcmp(client->view->name, "_default") != 0) {
+			name = client->view->name;
+			sep = ": view ";
+		} else {
+			name = "";
+			sep = "";
+		}
+		dns_name_format(client->query.qname, namebuf, sizeof(namebuf));
+		fprintf(f, "; client %s%s%s: '%s' requesttime %d\n",
+			peerbuf, sep, name, namebuf, client->requesttime);
+		client = ISC_LIST_NEXT(client, link);
+	}
+	UNLOCK(&manager->lock);
+}
+
+void
+ns_client_qnamereplace(ns_client_t *client, dns_name_t *name) {
+
+	if (client->manager != NULL)
+		LOCK(&client->manager->lock);
+	if (client->query.restarts > 0) {
+		/*
+		 * client->query.qname was dynamically allocated.
+		 */
+		dns_message_puttempname(client->message,
+					&client->query.qname);
+	}
+	client->query.qname = name;
+	if (client->manager != NULL)
+		UNLOCK(&client->manager->lock);
+}