dispatch.c

bind 9.3结合mysql数据库

		if (disp->maxrequests < maxrequests)
			disp->maxrequests = maxrequests;

		if ((disp->attributes & DNS_DISPATCHATTR_NOLISTEN) == 0 &&
		    (attributes & DNS_DISPATCHATTR_NOLISTEN) != 0)
		{
			disp->attributes |= DNS_DISPATCHATTR_NOLISTEN;
			if (disp->recv_pending != 0)
				isc_socket_cancel(disp->socket, disp->task,
						  ISC_SOCKCANCEL_RECV);
		}

		UNLOCK(&disp->lock);
		UNLOCK(&mgr->lock);

		*dispp = disp;

		return (ISC_R_SUCCESS);
	}

	/*
	 * Nope, create one.
	 */
	result = dispatch_createudp(mgr, sockmgr, taskmgr, localaddr,
				    maxrequests, attributes, &disp);
	if (result != ISC_R_SUCCESS) {
		UNLOCK(&mgr->lock);
		return (result);
	}

	UNLOCK(&mgr->lock);
	*dispp = disp;
	return (ISC_R_SUCCESS);
}

/*
 * mgr should be locked.
 */
static isc_result_t
dispatch_createudp(dns_dispatchmgr_t *mgr, isc_socketmgr_t *sockmgr,
		   isc_taskmgr_t *taskmgr,
		   isc_sockaddr_t *localaddr,
		   unsigned int maxrequests,
		   unsigned int attributes,
		   dns_dispatch_t **dispp)
{
	isc_result_t result;
	dns_dispatch_t *disp;
	isc_socket_t *sock;

	/*
	 * dispatch_allocate() checks mgr for us.
	 */
	disp = NULL;
	result = dispatch_allocate(mgr, maxrequests, &disp);
	if (result != ISC_R_SUCCESS)
		return (result);

	/*
	 * This assumes that the IP stack will *not* quickly reallocate
	 * the same port.  If it does continually reallocate the same port
	 * then we need a mechanism to hold all the blacklisted sockets
	 * until we find a usable socket.
	 */
 getsocket:
	result = create_socket(sockmgr, localaddr, &sock);
	if (result != ISC_R_SUCCESS)
		goto deallocate_dispatch;
	if (isc_sockaddr_getport(localaddr) == 0 && blacklisted(mgr, sock)) {
		isc_socket_detach(&sock);
		goto getsocket;
	}

	disp->socktype = isc_sockettype_udp;
	disp->socket = sock;
	disp->local = *localaddr;

	disp->task = NULL;
	result = isc_task_create(taskmgr, 0, &disp->task);
	if (result != ISC_R_SUCCESS)
		goto kill_socket;

	disp->ctlevent = isc_event_allocate(mgr->mctx, disp,
					    DNS_EVENT_DISPATCHCONTROL,
					    destroy_disp, disp,
					    sizeof(isc_event_t));
	if (disp->ctlevent == NULL)
		goto kill_task;

	isc_task_setname(disp->task, "udpdispatch", disp);

	attributes &= ~DNS_DISPATCHATTR_TCP;
	attributes |= DNS_DISPATCHATTR_UDP;
	disp->attributes = attributes;

	/*
	 * Append it to the dispatcher list.
	 */
	ISC_LIST_APPEND(mgr->list, disp, link);

	mgr_log(mgr, LVL(90), "created UDP dispatcher %p", disp);
	dispatch_log(disp, LVL(90), "created task %p", disp->task);
	dispatch_log(disp, LVL(90), "created socket %p", disp->socket);

	*dispp = disp;

	return (ISC_R_SUCCESS);

	/*
	 * Error returns.
	 */
 kill_task:
	isc_task_detach(&disp->task);
 kill_socket:
	isc_socket_detach(&disp->socket);
 deallocate_dispatch:
	dispatch_free(&disp);

	return (result);
}

void
dns_dispatch_attach(dns_dispatch_t *disp, dns_dispatch_t **dispp) {
	REQUIRE(VALID_DISPATCH(disp));
	REQUIRE(dispp != NULL && *dispp == NULL);

	LOCK(&disp->lock);
	disp->refcount++;
	UNLOCK(&disp->lock);

	*dispp = disp;
}

/*
 * It is important to lock the manager while we are deleting the dispatch,
 * since dns_dispatch_getudp will call dispatch_find, which returns to
 * the caller a dispatch but does not attach to it until later.  _getudp
 * locks the manager, however, so locking it here will keep us from attaching
 * to a dispatcher that is in the process of going away.
 */
void
dns_dispatch_detach(dns_dispatch_t **dispp) {
	dns_dispatch_t *disp;
	isc_boolean_t killit;

	REQUIRE(dispp != NULL && VALID_DISPATCH(*dispp));

	disp = *dispp;
	*dispp = NULL;

	LOCK(&disp->lock);

	INSIST(disp->refcount > 0);
	disp->refcount--;
	killit = ISC_FALSE;
	if (disp->refcount == 0) {
		if (disp->recv_pending > 0)
			isc_socket_cancel(disp->socket, disp->task,
					  ISC_SOCKCANCEL_RECV);
		disp->shutting_down = 1;
	}

	dispatch_log(disp, LVL(90), "detach: refcount %d", disp->refcount);

	killit = destroy_disp_ok(disp);
	UNLOCK(&disp->lock);
	if (killit)
		isc_task_send(disp->task, &disp->ctlevent);
}

isc_result_t
dns_dispatch_addresponse(dns_dispatch_t *disp, isc_sockaddr_t *dest,
			 isc_task_t *task, isc_taskaction_t action, void *arg,
			 dns_messageid_t *idp, dns_dispentry_t **resp)
{
	dns_dispentry_t *res;
	unsigned int bucket;
	dns_messageid_t id;
	int i;
	isc_boolean_t ok;
	dns_qid_t *qid;

	REQUIRE(VALID_DISPATCH(disp));
	REQUIRE(task != NULL);
	REQUIRE(dest != NULL);
	REQUIRE(resp != NULL && *resp == NULL);
	REQUIRE(idp != NULL);

	LOCK(&disp->lock);

	if (disp->shutting_down == 1) {
		UNLOCK(&disp->lock);
		return (ISC_R_SHUTTINGDOWN);
	}

	if (disp->requests >= disp->maxrequests) {
		UNLOCK(&disp->lock);
		return (ISC_R_QUOTA);
	}

	/*
	 * Try somewhat hard to find an unique ID.
	 */
	qid = DNS_QID(disp);
	LOCK(&qid->lock);
	id = dns_randomid(qid);
	bucket = dns_hash(qid, dest, id);
	ok = ISC_FALSE;
	for (i = 0; i < 64; i++) {
		if (bucket_search(qid, dest, id, bucket) == NULL) {
			ok = ISC_TRUE;
			break;
		}
		id += qid->qid_increment;
		id &= 0x0000ffff;
		bucket = dns_hash(qid, dest, id);
	}

	if (!ok) {
		UNLOCK(&qid->lock);
		UNLOCK(&disp->lock);
		return (ISC_R_NOMORE);
	}

	res = isc_mempool_get(disp->mgr->rpool);
	if (res == NULL) {
		UNLOCK(&qid->lock);
		UNLOCK(&disp->lock);
		return (ISC_R_NOMEMORY);
	}

	disp->refcount++;
	disp->requests++;
	res->task = NULL;
	isc_task_attach(task, &res->task);
	res->disp = disp;
	res->id = id;
	res->bucket = bucket;
	res->host = *dest;
	res->action = action;
	res->arg = arg;
	res->item_out = ISC_FALSE;
	ISC_LIST_INIT(res->items);
	ISC_LINK_INIT(res, link);
	res->magic = RESPONSE_MAGIC;
	ISC_LIST_APPEND(qid->qid_table[bucket], res, link);
	UNLOCK(&qid->lock);

	request_log(disp, res, LVL(90),
		    "attached to task %p", res->task);

	if (((disp->attributes & DNS_DISPATCHATTR_UDP) != 0) ||
	    ((disp->attributes & DNS_DISPATCHATTR_CONNECTED) != 0))
		startrecv(disp);

	UNLOCK(&disp->lock);

	*idp = id;
	*resp = res;

	return (ISC_R_SUCCESS);
}

void
dns_dispatch_starttcp(dns_dispatch_t *disp) {

	REQUIRE(VALID_DISPATCH(disp));

	dispatch_log(disp, LVL(90), "starttcp %p", disp->task);

	LOCK(&disp->lock);
	disp->attributes |= DNS_DISPATCHATTR_CONNECTED;
	startrecv(disp);
	UNLOCK(&disp->lock);
}

void
dns_dispatch_removeresponse(dns_dispentry_t **resp,
			    dns_dispatchevent_t **sockevent)
{
	dns_dispatchmgr_t *mgr;
	dns_dispatch_t *disp;
	dns_dispentry_t *res;
	dns_dispatchevent_t *ev;
	unsigned int bucket;
	isc_boolean_t killit;
	unsigned int n;
	isc_eventlist_t events;
	dns_qid_t *qid;

	REQUIRE(resp != NULL);
	REQUIRE(VALID_RESPONSE(*resp));

	res = *resp;
	*resp = NULL;

	disp = res->disp;
	REQUIRE(VALID_DISPATCH(disp));
	mgr = disp->mgr;
	REQUIRE(VALID_DISPATCHMGR(mgr));

	qid = DNS_QID(disp);

	if (sockevent != NULL) {
		REQUIRE(*sockevent != NULL);
		ev = *sockevent;
		*sockevent = NULL;
	} else {
		ev = NULL;
	}

	LOCK(&disp->lock);

	INSIST(disp->requests > 0);
	disp->requests--;
	INSIST(disp->refcount > 0);
	disp->refcount--;
	killit = ISC_FALSE;
	if (disp->refcount == 0) {
		if (disp->recv_pending > 0)
			isc_socket_cancel(disp->socket, disp->task,
					  ISC_SOCKCANCEL_RECV);
		disp->shutting_down = 1;
	}

	bucket = res->bucket;

	LOCK(&qid->lock);
	ISC_LIST_UNLINK(qid->qid_table[bucket], res, link);
	UNLOCK(&qid->lock);

	if (ev == NULL && res->item_out) {
		/*
		 * We've posted our event, but the caller hasn't gotten it
		 * yet.  Take it back.
		 */
		ISC_LIST_INIT(events);
		n = isc_task_unsend(res->task, res, DNS_EVENT_DISPATCH,
				    NULL, &events);
		/*
		 * We had better have gotten it back.
		 */
		INSIST(n == 1);
		ev = (dns_dispatchevent_t *)ISC_LIST_HEAD(events);
	}

	if (ev != NULL) {
		REQUIRE(res->item_out == ISC_TRUE);
		res->item_out = ISC_FALSE;
		if (ev->buffer.base != NULL)
			free_buffer(disp, ev->buffer.base, ev->buffer.length);
		free_event(disp, ev);
	}

	request_log(disp, res, LVL(90), "detaching from task %p", res->task);
	isc_task_detach(&res->task);

	/*
	 * Free any buffered requests as well
	 */
	ev = ISC_LIST_HEAD(res->items);
	while (ev != NULL) {
		ISC_LIST_UNLINK(res->items, ev, ev_link);
		if (ev->buffer.base != NULL)
			free_buffer(disp, ev->buffer.base, ev->buffer.length);
		free_event(disp, ev);
		ev = ISC_LIST_HEAD(res->items);
	}
	res->magic = 0;
	isc_mempool_put(disp->mgr->rpool, res);
	if (disp->shutting_down == 1)
		do_cancel(disp);
	else
		startrecv(disp);

	killit = destroy_disp_ok(disp);
	UNLOCK(&disp->lock);
	if (killit)
		isc_task_send(disp->task, &disp->ctlevent);
}

static void
do_cancel(dns_dispatch_t *disp) {
	dns_dispatchevent_t *ev;
	dns_dispentry_t *resp;
	dns_qid_t *qid;

	if (disp->shutdown_out == 1)
		return;

	qid = DNS_QID(disp);

	/*
	 * Search for the first response handler without packets outstanding.
	 */
	LOCK(&qid->lock);
	for (resp = linear_first(qid);
	     resp != NULL && resp->item_out != ISC_FALSE;
	     /* Empty. */)
		resp = linear_next(qid, resp);
	/*
	 * No one to send the cancel event to, so nothing to do.
	 */
	if (resp == NULL)
		goto unlock;

	/*
	 * Send the shutdown failsafe event to this resp.
	 */
	ev = disp->failsafe_ev;
	ISC_EVENT_INIT(ev, sizeof(*ev), 0, NULL, DNS_EVENT_DISPATCH,
		       resp->action, resp->arg, resp, NULL, NULL);
	ev->result = disp->shutdown_why;
	ev->buffer.base = NULL;
	ev->buffer.length = 0;
	disp->shutdown_out = 1;
	request_log(disp, resp, LVL(10),
		    "cancel: failsafe event %p -> task %p",
		    ev, resp->task);
	resp->item_out = ISC_TRUE;
	isc_task_send(resp->task, ISC_EVENT_PTR(&ev));
 unlock:
	UNLOCK(&qid->lock);
}

isc_socket_t *
dns_dispatch_getsocket(dns_dispatch_t *disp) {
	REQUIRE(VALID_DISPATCH(disp));

	return (disp->socket);
}

isc_result_t
dns_dispatch_getlocaladdress(dns_dispatch_t *disp, isc_sockaddr_t *addrp) {

	REQUIRE(VALID_DISPATCH(disp));
	REQUIRE(addrp != NULL);

	if (disp->socktype == isc_sockettype_udp) {
		*addrp = disp->local;
		return (ISC_R_SUCCESS);
	}
	return (ISC_R_NOTIMPLEMENTED);
}

void
dns_dispatch_cancel(dns_dispatch_t *disp) {
	REQUIRE(VALID_DISPATCH(disp));

	LOCK(&disp->lock);

	if (disp->shutting_down == 1) {
		UNLOCK(&disp->lock);
		return;
	}

	disp->shutdown_why = ISC_R_CANCELED;
	disp->shutting_down = 1;
	do_cancel(disp);

	UNLOCK(&disp->lock);

	return;
}

void
dns_dispatch_changeattributes(dns_dispatch_t *disp,
			      unsigned int attributes, unsigned int mask)
{
	REQUIRE(VALID_DISPATCH(disp));

	/* XXXMLG
	 * Should check for valid attributes here!
	 */

	LOCK(&disp->lock);

	if ((mask & DNS_DISPATCHATTR_NOLISTEN) != 0) {
		if ((disp->attributes & DNS_DISPATCHATTR_NOLISTEN) != 0 &&
		    (attributes & DNS_DISPATCHATTR_NOLISTEN) == 0) {
			disp->attributes &= ~DNS_DISPATCHATTR_NOLISTEN;
			startrecv(disp);
		} else if ((disp->attributes & DNS_DISPATCHATTR_NOLISTEN)
			   == 0 &&
			   (attributes & DNS_DISPATCHATTR_NOLISTEN) != 0) {
			disp->attributes |= DNS_DISPATCHATTR_NOLISTEN;
			if (disp->recv_pending != 0)
				isc_socket_cancel(disp->socket, disp->task,
						  ISC_SOCKCANCEL_RECV);
		}
	}

	disp->attributes &= ~mask;
	disp->attributes |= (attributes & mask);
	UNLOCK(&disp->lock);
}

void
dns_dispatch_importrecv(dns_dispatch_t *disp, isc_event_t *event) {
	void *buf;
	isc_socketevent_t *sevent, *newsevent;

	REQUIRE(VALID_DISPATCH(disp));
	REQUIRE((disp->attributes & DNS_DISPATCHATTR_NOLISTEN) != 0);
	REQUIRE(event != NULL);

	sevent = (isc_socketevent_t *)event;

	INSIST(sevent->n <= disp->mgr->buffersize);
	newsevent = (isc_socketevent_t *)
		    isc_event_allocate(disp->mgr->mctx, NULL,
				      DNS_EVENT_IMPORTRECVDONE, udp_recv,
				      disp, sizeof(isc_socketevent_t));
	if (newsevent == NULL)
		return;

	buf = allocate_udp_buffer(disp);
	if (buf == NULL) {
		isc_event_free(ISC_EVENT_PTR(&newsevent));
		return;
	}
	memcpy(buf, sevent->region.base, sevent->n);
	newsevent->region.base = buf;
	newsevent->region.length = disp->mgr->buffersize;
	newsevent->n = sevent->n;
	newsevent->result = sevent->result;
	newsevent->address = sevent->address;
	newsevent->timestamp = sevent->timestamp;
	newsevent->pktinfo = sevent->pktinfo;
	newsevent->attributes = sevent->attributes;
	
	isc_task_send(disp->task, ISC_EVENT_PTR(&newsevent));
}

#if 0
void
dns_dispatchmgr_dump(dns_dispatchmgr_t *mgr) {
	dns_dispatch_t *disp;
	char foo[1024];

	disp = ISC_LIST_HEAD(mgr->list);
	while (disp != NULL) {
		isc_sockaddr_format(&disp->local, foo, sizeof(foo));
		printf("\tdispatch %p, addr %s\n", disp, foo);
		disp = ISC_LIST_NEXT(disp, link);
	}
}
#endif