request.c

bind-3.2.

/*
 * Copyright (C) 2000, 2001  Internet Software Consortium.
 *
 * Permission to use, copy, modify, and 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 INTERNET SOFTWARE CONSORTIUM
 * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
 * INTERNET SOFTWARE CONSORTIUM 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: request.c,v 1.64.2.1 2001/08/31 02:07:11 marka Exp $ */

#include <config.h>

#include <isc/magic.h>
#include <isc/mem.h>
#include <isc/task.h>
#include <isc/timer.h>
#include <isc/util.h>

#include <dns/acl.h>
#include <dns/compress.h>
#include <dns/dispatch.h>
#include <dns/events.h>
#include <dns/log.h>
#include <dns/message.h>
#include <dns/rdata.h>
#include <dns/rdatastruct.h>
#include <dns/request.h>
#include <dns/result.h>
#include <dns/tsig.h>

#define REQUESTMGR_MAGIC	ISC_MAGIC('R', 'q', 'u', 'M')
#define VALID_REQUESTMGR(mgr)	ISC_MAGIC_VALID(mgr, REQUESTMGR_MAGIC)

#define REQUEST_MAGIC		ISC_MAGIC('R', 'q', 'u', '!')
#define VALID_REQUEST(request)	ISC_MAGIC_VALID(request, REQUEST_MAGIC)

typedef ISC_LIST(dns_request_t) dns_requestlist_t;

#define DNS_REQUEST_NLOCKS 7

struct dns_requestmgr {
	unsigned int			magic;
	isc_mutex_t			lock;
	isc_mem_t		       *mctx;

	/* locked */
	isc_int32_t			eref;
	isc_int32_t			iref;
	isc_timermgr_t		       *timermgr;
	isc_socketmgr_t		       *socketmgr;
	isc_taskmgr_t		       *taskmgr;
	dns_dispatchmgr_t	       *dispatchmgr;
	dns_dispatch_t		       *dispatchv4;
	dns_dispatch_t		       *dispatchv6;
	isc_boolean_t			exiting;
	isc_eventlist_t			whenshutdown;
	unsigned int			hash;
	isc_mutex_t			locks[DNS_REQUEST_NLOCKS];
	dns_requestlist_t 		requests;
};

struct dns_request {
	unsigned int			magic;
	unsigned int			hash;
	isc_mem_t		       *mctx;
	isc_int32_t			flags;
	ISC_LINK(dns_request_t) 	link;
	isc_buffer_t		       *query;
	isc_buffer_t		       *answer;
	dns_requestevent_t	       *event;
	dns_dispatch_t		       *dispatch;
	dns_dispentry_t		       *dispentry;
	isc_timer_t		       *timer;
	dns_requestmgr_t	       *requestmgr;
	isc_buffer_t		       *tsig;
	dns_tsigkey_t		       *tsigkey;
	isc_event_t			ctlevent;
	isc_boolean_t			canceling; /* ctlevent outstanding */
};

#define DNS_REQUEST_F_CONNECTING 0x0001
#define DNS_REQUEST_F_SENDING 0x0002
#define DNS_REQUEST_F_CANCELED 0x0004	/* ctlevent received, or otherwise
					   synchronously canceled */
#define DNS_REQUEST_F_TIMEDOUT 0x0008	/* cancelled due to a timeout */
#define DNS_REQUEST_F_TCP 0x0010	/* This request used TCP */
#define DNS_REQUEST_CANCELED(r) \
	(((r)->flags & DNS_REQUEST_F_CANCELED) != 0)
#define DNS_REQUEST_CONNECTING(r) \
	(((r)->flags & DNS_REQUEST_F_CONNECTING) != 0)
#define DNS_REQUEST_SENDING(r) \
	(((r)->flags & DNS_REQUEST_F_SENDING) != 0)
#define DNS_REQUEST_TIMEDOUT(r) \
	(((r)->flags & DNS_REQUEST_F_TIMEDOUT) != 0)


/***
 *** Forward
 ***/

static void mgr_destroy(dns_requestmgr_t *requestmgr);
static void mgr_shutdown(dns_requestmgr_t *requestmgr);
static unsigned int mgr_gethash(dns_requestmgr_t *requestmgr);
static void send_shutdown_events(dns_requestmgr_t *requestmgr);

static isc_result_t req_render(dns_message_t *message, isc_buffer_t **buffer,
			       unsigned int options, isc_mem_t *mctx);
static void req_senddone(isc_task_t *task, isc_event_t *event);
static void req_response(isc_task_t *task, isc_event_t *event);
static void req_timeout(isc_task_t *task, isc_event_t *event);
static void req_connected(isc_task_t *task, isc_event_t *event);
static void req_sendevent(dns_request_t *request, isc_result_t result);
static void req_cancel(dns_request_t *request);
static void req_destroy(dns_request_t *request);
static void req_log(int level, const char *fmt, ...) ISC_FORMAT_PRINTF(2, 3);
static void do_cancel(isc_task_t *task, isc_event_t *event);

/***
 *** Public
 ***/

isc_result_t
dns_requestmgr_create(isc_mem_t *mctx,
		      isc_timermgr_t *timermgr,
		      isc_socketmgr_t *socketmgr,
		      isc_taskmgr_t *taskmgr,
		      dns_dispatchmgr_t *dispatchmgr,
		      dns_dispatch_t *dispatchv4,
		      dns_dispatch_t *dispatchv6,
		      dns_requestmgr_t **requestmgrp)
{
	dns_requestmgr_t *requestmgr;
	isc_socket_t *socket;
	isc_result_t result;
	int i;

	req_log(ISC_LOG_DEBUG(3), "dns_requestmgr_create");

	REQUIRE(requestmgrp != NULL && *requestmgrp == NULL);
	REQUIRE(timermgr != NULL);
	REQUIRE(socketmgr != NULL);
	REQUIRE(taskmgr != NULL);
	REQUIRE(dispatchmgr != NULL);
	if (dispatchv4 != NULL) {
		socket = dns_dispatch_getsocket(dispatchv4);
		REQUIRE(isc_socket_gettype(socket) == isc_sockettype_udp);
	}
	if (dispatchv6 != NULL) {
		socket = dns_dispatch_getsocket(dispatchv6);
		REQUIRE(isc_socket_gettype(socket) == isc_sockettype_udp);
	}

	requestmgr = isc_mem_get(mctx, sizeof(*requestmgr));
	if (requestmgr == NULL)
		return (ISC_R_NOMEMORY);

	result = isc_mutex_init(&requestmgr->lock);
	if (result != ISC_R_SUCCESS) {
		isc_mem_put(mctx, requestmgr, sizeof(*requestmgr));
		return (result);
	}
	for (i = 0; i < DNS_REQUEST_NLOCKS; i++) {
		result = isc_mutex_init(&requestmgr->locks[i]);
		if (result != ISC_R_SUCCESS) {
			while (--i >= 0)
				DESTROYLOCK(&requestmgr->locks[i]);
			DESTROYLOCK(&requestmgr->lock);
			isc_mem_put(mctx, requestmgr, sizeof(*requestmgr));
			return (result);
		}
	}
	requestmgr->timermgr = timermgr;
	requestmgr->socketmgr = socketmgr;
	requestmgr->taskmgr = taskmgr;
	requestmgr->dispatchmgr = dispatchmgr;
	requestmgr->dispatchv4 = NULL;
	if (dispatchv4 != NULL)
		dns_dispatch_attach(dispatchv4, &requestmgr->dispatchv4);
	requestmgr->dispatchv6 = NULL;
	if (dispatchv6 != NULL)
		dns_dispatch_attach(dispatchv6, &requestmgr->dispatchv6);
	requestmgr->mctx = NULL;
	isc_mem_attach(mctx, &requestmgr->mctx);
	requestmgr->eref = 1;	/* implict attach */
	requestmgr->iref = 0;
	ISC_LIST_INIT(requestmgr->whenshutdown);
	ISC_LIST_INIT(requestmgr->requests);
	requestmgr->exiting = ISC_FALSE;
	requestmgr->hash = 0;
	requestmgr->magic = REQUESTMGR_MAGIC;

	req_log(ISC_LOG_DEBUG(3), "dns_requestmgr_create: %p", requestmgr);

	*requestmgrp = requestmgr;
	return (ISC_R_SUCCESS);
}

void
dns_requestmgr_whenshutdown(dns_requestmgr_t *requestmgr, isc_task_t *task,
			    isc_event_t **eventp)
{
	isc_task_t *clone;
	isc_event_t *event;

	req_log(ISC_LOG_DEBUG(3), "dns_requestmgr_whenshutdown");

	REQUIRE(VALID_REQUESTMGR(requestmgr));
	REQUIRE(eventp != NULL);

	event = *eventp;
	*eventp = NULL;

	LOCK(&requestmgr->lock);

	if (requestmgr->exiting) {
		/*
		 * We're already shutdown.  Send the event.
		 */
		event->ev_sender = requestmgr;
		isc_task_send(task, &event);
	} else {
		clone = NULL;
		isc_task_attach(task, &clone);
		event->ev_sender = clone;
		ISC_LIST_APPEND(requestmgr->whenshutdown, event, ev_link);
	}
	UNLOCK(&requestmgr->lock);
}

void
dns_requestmgr_shutdown(dns_requestmgr_t *requestmgr) {

	REQUIRE(VALID_REQUESTMGR(requestmgr));

	req_log(ISC_LOG_DEBUG(3), "dns_requestmgr_shutdown: %p", requestmgr);

	LOCK(&requestmgr->lock);
	mgr_shutdown(requestmgr);
	UNLOCK(&requestmgr->lock);
}

static void
mgr_shutdown(dns_requestmgr_t *requestmgr) {
	dns_request_t *request;

	/*
	 * Caller holds lock.
	 */
	if (!requestmgr->exiting) {
		requestmgr->exiting = ISC_TRUE;
		for (request = ISC_LIST_HEAD(requestmgr->requests);
		     request != NULL;
		     request = ISC_LIST_NEXT(request, link)) {
			dns_request_cancel(request);
		}
		if (requestmgr->iref == 0) {
			INSIST(ISC_LIST_EMPTY(requestmgr->requests));
			send_shutdown_events(requestmgr);
		}
	}
}

static void
requestmgr_attach(dns_requestmgr_t *source, dns_requestmgr_t **targetp) {

	/*
	 * Locked by caller.
	 */

	REQUIRE(VALID_REQUESTMGR(source));
	REQUIRE(targetp != NULL && *targetp == NULL);

	REQUIRE(!source->exiting);

	source->iref++;
	*targetp = source;

	req_log(ISC_LOG_DEBUG(3), "requestmgr_attach: %p: eref %d iref %d",
		source, source->eref, source->iref);
}

static void
requestmgr_detach(dns_requestmgr_t **requestmgrp) {
	dns_requestmgr_t *requestmgr;
	isc_boolean_t need_destroy = ISC_FALSE;

	REQUIRE(requestmgrp != NULL);
	requestmgr = *requestmgrp;
	REQUIRE(VALID_REQUESTMGR(requestmgr));

	*requestmgrp = NULL;
	LOCK(&requestmgr->lock);
	INSIST(requestmgr->iref > 0);
	requestmgr->iref--;

	req_log(ISC_LOG_DEBUG(3), "requestmgr_detach: %p: eref %d iref %d",
		requestmgr, requestmgr->eref, requestmgr->iref);

	if (requestmgr->iref == 0 && requestmgr->exiting) {
		INSIST(ISC_LIST_HEAD(requestmgr->requests) == NULL);
		send_shutdown_events(requestmgr);
		if (requestmgr->eref == 0)
			need_destroy = ISC_TRUE;
	}
	UNLOCK(&requestmgr->lock);

	if (need_destroy)
		mgr_destroy(requestmgr);
}

void
dns_requestmgr_attach(dns_requestmgr_t *source, dns_requestmgr_t **targetp) {

	REQUIRE(VALID_REQUESTMGR(source));
	REQUIRE(targetp != NULL && *targetp == NULL);
	REQUIRE(!source->exiting);

	LOCK(&source->lock);
	source->eref++;
	*targetp = source;
	UNLOCK(&source->lock);

	req_log(ISC_LOG_DEBUG(3), "dns_requestmgr_attach: %p: eref %d iref %d",
		source, source->eref, source->iref);
}

void
dns_requestmgr_detach(dns_requestmgr_t **requestmgrp) {
	dns_requestmgr_t *requestmgr;
	isc_boolean_t need_destroy = ISC_FALSE;

	REQUIRE(requestmgrp != NULL);
	requestmgr = *requestmgrp;
	REQUIRE(VALID_REQUESTMGR(requestmgr));

	LOCK(&requestmgr->lock);
	INSIST(requestmgr->eref > 0);
	requestmgr->eref--;

	req_log(ISC_LOG_DEBUG(3), "dns_requestmgr_detach: %p: eref %d iref %d",
		requestmgr, requestmgr->eref, requestmgr->iref);

	if (requestmgr->eref == 0 && requestmgr->iref == 0) {
		INSIST(requestmgr->exiting &&
		       ISC_LIST_HEAD(requestmgr->requests) == NULL);
		need_destroy = ISC_TRUE;
	}
	UNLOCK(&requestmgr->lock);

	if (need_destroy)
		mgr_destroy(requestmgr);

	*requestmgrp = NULL;
}

static void
send_shutdown_events(dns_requestmgr_t *requestmgr) {
	isc_event_t *event, *next_event;
	isc_task_t *etask;

	req_log(ISC_LOG_DEBUG(3), "send_shutdown_events: %p", requestmgr);

	/*
	 * Caller must be holding the manager lock.
	 */
	for (event = ISC_LIST_HEAD(requestmgr->whenshutdown);
	     event != NULL;
	     event = next_event) {
		next_event = ISC_LIST_NEXT(event, ev_link);
		ISC_LIST_UNLINK(requestmgr->whenshutdown, event, ev_link);
		etask = event->ev_sender;
		event->ev_sender = requestmgr;
		isc_task_sendanddetach(&etask, &event);
	}
}

static void
mgr_destroy(dns_requestmgr_t *requestmgr) {
	int i;
	isc_mem_t *mctx;

	req_log(ISC_LOG_DEBUG(3), "mgr_destroy");

	REQUIRE(requestmgr->eref == 0);
	REQUIRE(requestmgr->iref == 0);

	DESTROYLOCK(&requestmgr->lock);
	for (i = 0; i < DNS_REQUEST_NLOCKS; i++)
		DESTROYLOCK(&requestmgr->locks[i]);
	if (requestmgr->dispatchv4 != NULL)
		dns_dispatch_detach(&requestmgr->dispatchv4);
	if (requestmgr->dispatchv6 != NULL)
		dns_dispatch_detach(&requestmgr->dispatchv6);
	requestmgr->magic = 0;
	mctx = requestmgr->mctx;
	isc_mem_put(mctx, requestmgr, sizeof *requestmgr);
	isc_mem_detach(&mctx);
}

static unsigned int
mgr_gethash(dns_requestmgr_t *requestmgr) {
	req_log(ISC_LOG_DEBUG(3), "mgr_gethash");
	/*
	 * Locked by caller.
	 */
	requestmgr->hash++;
	return (requestmgr->hash % DNS_REQUEST_NLOCKS);
}

static inline isc_result_t
req_send(dns_request_t *request, isc_task_t *task, isc_sockaddr_t *address) {
	isc_region_t r;
	isc_socket_t *socket;
	isc_result_t result;

	req_log(ISC_LOG_DEBUG(3), "req_send: request %p", request);

	REQUIRE(VALID_REQUEST(request));
	socket = dns_dispatch_getsocket(request->dispatch);
	isc_buffer_usedregion(request->query, &r);
	result = isc_socket_sendto(socket, &r, task, req_senddone,
				  request, address, NULL);
	if (result == ISC_R_SUCCESS)
		request->flags |= DNS_REQUEST_F_SENDING;
	return (result);
}

static isc_result_t
new_request(isc_mem_t *mctx, dns_request_t **requestp) {
	dns_request_t *request;

	request = isc_mem_get(mctx, sizeof(*request));
	if (request == NULL)
		return (ISC_R_NOMEMORY);

	/*
	 * Zero structure.
	 */
	request->magic = 0;
	request->mctx = NULL;
	request->flags = 0;
	ISC_LINK_INIT(request, link);
	request->query = NULL;