dispatch.c

bind 9.3结合mysql数据库

		disp->recv_pending = 0;
	}

	if (disp->shutting_down) {
		/*
		 * This dispatcher is shutting down.
		 */
		free_buffer(disp, ev->region.base, ev->region.length);

		isc_event_free(&ev_in);
		ev = NULL;

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

		return;
	}

	if (ev->result != ISC_R_SUCCESS) {
		free_buffer(disp, ev->region.base, ev->region.length);

		if (ev->result != ISC_R_CANCELED)
			dispatch_log(disp, ISC_LOG_ERROR,
				     "odd socket result in udp_recv(): %s",
				     isc_result_totext(ev->result));

		UNLOCK(&disp->lock);
		isc_event_free(&ev_in);
		return;
	}

	/*
	 * If this is from a blackholed address, drop it.
	 */
	isc_netaddr_fromsockaddr(&netaddr, &ev->address);
	if (disp->mgr->blackhole != NULL &&
	    dns_acl_match(&netaddr, NULL, disp->mgr->blackhole,
		    	  NULL, &match, NULL) == ISC_R_SUCCESS &&
	    match > 0)
	{
		if (isc_log_wouldlog(dns_lctx, LVL(10))) {
			char netaddrstr[ISC_NETADDR_FORMATSIZE];
			isc_netaddr_format(&netaddr, netaddrstr,
					   sizeof(netaddrstr));
			dispatch_log(disp, LVL(10),
				     "blackholed packet from %s",
				     netaddrstr);
		}
		free_buffer(disp, ev->region.base, ev->region.length);
		goto restart;
	}

	/*
	 * Peek into the buffer to see what we can see.
	 */
	isc_buffer_init(&source, ev->region.base, ev->region.length);
	isc_buffer_add(&source, ev->n);
	dres = dns_message_peekheader(&source, &id, &flags);
	if (dres != ISC_R_SUCCESS) {
		free_buffer(disp, ev->region.base, ev->region.length);
		dispatch_log(disp, LVL(10), "got garbage packet");
		goto restart;
	}

	dispatch_log(disp, LVL(92),
		     "got valid DNS message header, /QR %c, id %u",
		     ((flags & DNS_MESSAGEFLAG_QR) ? '1' : '0'), id);

	/*
	 * Look at flags.  If query, drop it. If response,
	 * look to see where it goes.
	 */
	queue_response = ISC_FALSE;
	if ((flags & DNS_MESSAGEFLAG_QR) == 0) {
		/* query */
		free_buffer(disp, ev->region.base, ev->region.length);
		goto restart;
	}

	/* response */
	bucket = dns_hash(qid, &ev->address, id);
	LOCK(&qid->lock);
	resp = bucket_search(qid, &ev->address, id, bucket);
	dispatch_log(disp, LVL(90),
		     "search for response in bucket %d: %s",
		     bucket, (resp == NULL ? "not found" : "found"));

	if (resp == NULL) {
		free_buffer(disp, ev->region.base, ev->region.length);
		goto unlock;
	} 
	queue_response = resp->item_out;
	rev = allocate_event(resp->disp);
	if (rev == NULL) {
		free_buffer(disp, ev->region.base, ev->region.length);
		goto unlock;
	}

	/*
	 * At this point, rev contains the event we want to fill in, and
	 * resp contains the information on the place to send it to.
	 * Send the event off.
	 */
	isc_buffer_init(&rev->buffer, ev->region.base, ev->region.length);
	isc_buffer_add(&rev->buffer, ev->n);
	rev->result = ISC_R_SUCCESS;
	rev->id = id;
	rev->addr = ev->address;
	rev->pktinfo = ev->pktinfo;
	rev->attributes = ev->attributes;
	if (queue_response) {
		ISC_LIST_APPEND(resp->items, rev, ev_link);
	} else {
		ISC_EVENT_INIT(rev, sizeof(*rev), 0, NULL,
			       DNS_EVENT_DISPATCH,
			       resp->action, resp->arg, resp, NULL, NULL);
		request_log(disp, resp, LVL(90),
			    "[a] Sent event %p buffer %p len %d to task %p",
			    rev, rev->buffer.base, rev->buffer.length,
			    resp->task);
		resp->item_out = ISC_TRUE;
		isc_task_send(resp->task, ISC_EVENT_PTR(&rev));
	}
 unlock:
	UNLOCK(&qid->lock);

	/*
	 * Restart recv() to get the next packet.
	 */
 restart:
	startrecv(disp);

	UNLOCK(&disp->lock);

	isc_event_free(&ev_in);
}

/*
 * General flow:
 *
 * If I/O result == CANCELED, EOF, or error, notify everyone as the
 * various queues drain.
 *
 * If query, restart.
 *
 * If response:
 *	Allocate event, fill in details.
 *		If cannot allocate, restart.
 *	find target.  If not found, restart.
 *	if event queue is not empty, queue.  else, send.
 *	restart.
 */
static void
tcp_recv(isc_task_t *task, isc_event_t *ev_in) {
	dns_dispatch_t *disp = ev_in->ev_arg;
	dns_tcpmsg_t *tcpmsg = &disp->tcpmsg;
	dns_messageid_t id;
	isc_result_t dres;
	unsigned int flags;
	dns_dispentry_t *resp;
	dns_dispatchevent_t *rev;
	unsigned int bucket;
	isc_boolean_t killit;
	isc_boolean_t queue_response;
	dns_qid_t *qid;
	int level;
	char buf[ISC_SOCKADDR_FORMATSIZE];

	UNUSED(task);

	REQUIRE(VALID_DISPATCH(disp));

	qid = disp->qid;

	dispatch_log(disp, LVL(90),
		     "got TCP packet: requests %d, buffers %d, recvs %d",
		     disp->requests, disp->tcpbuffers, disp->recv_pending);

	LOCK(&disp->lock);

	INSIST(disp->recv_pending != 0);
	disp->recv_pending = 0;

	if (disp->refcount == 0) {
		/*
		 * This dispatcher is shutting down.  Force cancelation.
		 */
		tcpmsg->result = ISC_R_CANCELED;
	}

	if (tcpmsg->result != ISC_R_SUCCESS) {
		switch (tcpmsg->result) {
		case ISC_R_CANCELED:
			break;
			
		case ISC_R_EOF:
			dispatch_log(disp, LVL(90), "shutting down on EOF");
			do_cancel(disp);
			break;

		case ISC_R_CONNECTIONRESET:
			level = ISC_LOG_INFO;
			goto logit;

		default:
			level = ISC_LOG_ERROR;
		logit:
			isc_sockaddr_format(&tcpmsg->address, buf, sizeof(buf));
			dispatch_log(disp, level, "shutting down due to TCP "
				     "receive error: %s: %s", buf,
				     isc_result_totext(tcpmsg->result));
			do_cancel(disp);
			break;
		}

		/*
		 * The event is statically allocated in the tcpmsg
		 * structure, and destroy_disp() frees the tcpmsg, so we must
		 * free the event *before* calling destroy_disp().
		 */
		isc_event_free(&ev_in);

		disp->shutting_down = 1;
		disp->shutdown_why = tcpmsg->result;

		/*
		 * If the recv() was canceled pass the word on.
		 */
		killit = destroy_disp_ok(disp);
		UNLOCK(&disp->lock);
		if (killit)
			isc_task_send(disp->task, &disp->ctlevent);
		return;
	}

	dispatch_log(disp, LVL(90), "result %d, length == %d, addr = %p",
		     tcpmsg->result,
		     tcpmsg->buffer.length, tcpmsg->buffer.base);

	/*
	 * Peek into the buffer to see what we can see.
	 */
	dres = dns_message_peekheader(&tcpmsg->buffer, &id, &flags);
	if (dres != ISC_R_SUCCESS) {
		dispatch_log(disp, LVL(10), "got garbage packet");
		goto restart;
	}

	dispatch_log(disp, LVL(92),
		     "got valid DNS message header, /QR %c, id %u",
		     ((flags & DNS_MESSAGEFLAG_QR) ? '1' : '0'), id);

	/*
	 * Allocate an event to send to the query or response client, and
	 * allocate a new buffer for our use.
	 */

	/*
	 * Look at flags.  If query, drop it. If response,
	 * look to see where it goes.
	 */
	queue_response = ISC_FALSE;
	if ((flags & DNS_MESSAGEFLAG_QR) == 0) {
		/*
		 * Query.
		 */
		goto restart;
	}

	/*
	 * Response.
	 */
	bucket = dns_hash(qid, &tcpmsg->address, id);
	LOCK(&qid->lock);
	resp = bucket_search(qid, &tcpmsg->address, id, bucket);
	dispatch_log(disp, LVL(90),
		     "search for response in bucket %d: %s",
		     bucket, (resp == NULL ? "not found" : "found"));

	if (resp == NULL)
		goto unlock;
	queue_response = resp->item_out;
	rev = allocate_event(disp);
	if (rev == NULL)
		goto unlock;

	/*
	 * At this point, rev contains the event we want to fill in, and
	 * resp contains the information on the place to send it to.
	 * Send the event off.
	 */
	dns_tcpmsg_keepbuffer(tcpmsg, &rev->buffer);
	disp->tcpbuffers++;
	rev->result = ISC_R_SUCCESS;
	rev->id = id;
	rev->addr = tcpmsg->address;
	if (queue_response) {
		ISC_LIST_APPEND(resp->items, rev, ev_link);
	} else {
		ISC_EVENT_INIT(rev, sizeof(*rev), 0, NULL, DNS_EVENT_DISPATCH,
			       resp->action, resp->arg, resp, NULL, NULL);
		request_log(disp, resp, LVL(90),
			    "[b] Sent event %p buffer %p len %d to task %p",
			    rev, rev->buffer.base, rev->buffer.length,
			    resp->task);
		resp->item_out = ISC_TRUE;
		isc_task_send(resp->task, ISC_EVENT_PTR(&rev));
	}
 unlock:
	UNLOCK(&qid->lock);

	/*
	 * Restart recv() to get the next packet.
	 */
 restart:
	startrecv(disp);

	UNLOCK(&disp->lock);

	isc_event_free(&ev_in);
}

/*
 * disp must be locked.
 */
static void
startrecv(dns_dispatch_t *disp) {
	isc_result_t res;
	isc_region_t region;

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

	if ((disp->attributes & DNS_DISPATCHATTR_NOLISTEN) != 0)
		return;

	if (disp->recv_pending != 0)
		return;

	if (disp->mgr->buffers >= disp->mgr->maxbuffers)
		return;

	switch (disp->socktype) {
		/*
		 * UDP reads are always maximal.
		 */
	case isc_sockettype_udp:
		region.length = disp->mgr->buffersize;
		region.base = allocate_udp_buffer(disp);
		if (region.base == NULL)
			return;
		res = isc_socket_recv(disp->socket, &region, 1,
				      disp->task, udp_recv, disp);
		if (res != ISC_R_SUCCESS) {
			free_buffer(disp, region.base, region.length);
			disp->shutdown_why = res;
			disp->shutting_down = 1;
			do_cancel(disp);
			return;
		}
		INSIST(disp->recv_pending == 0);
		disp->recv_pending = 1;
		break;

	case isc_sockettype_tcp:
		res = dns_tcpmsg_readmessage(&disp->tcpmsg, disp->task,
					     tcp_recv, disp);
		if (res != ISC_R_SUCCESS) {
			disp->shutdown_why = res;
			disp->shutting_down = 1;
			do_cancel(disp);
			return;
		}
		INSIST(disp->recv_pending == 0);
		disp->recv_pending = 1;
		break;
	}
}

/*
 * Mgr must be locked when calling this function.
 */
static isc_boolean_t
destroy_mgr_ok(dns_dispatchmgr_t *mgr) {
	mgr_log(mgr, LVL(90),
		"destroy_mgr_ok: shuttingdown=%d, listnonempty=%d, "
		"epool=%d, rpool=%d, dpool=%d",
		MGR_IS_SHUTTINGDOWN(mgr), !ISC_LIST_EMPTY(mgr->list),
		isc_mempool_getallocated(mgr->epool),
		isc_mempool_getallocated(mgr->rpool),
		isc_mempool_getallocated(mgr->dpool));
	if (!MGR_IS_SHUTTINGDOWN(mgr))
		return (ISC_FALSE);
	if (!ISC_LIST_EMPTY(mgr->list))
		return (ISC_FALSE);
	if (isc_mempool_getallocated(mgr->epool) != 0)
		return (ISC_FALSE);
	if (isc_mempool_getallocated(mgr->rpool) != 0)
		return (ISC_FALSE);
	if (isc_mempool_getallocated(mgr->dpool) != 0)
		return (ISC_FALSE);

	return (ISC_TRUE);
}

/*
 * Mgr must be unlocked when calling this function.
 */
static void
destroy_mgr(dns_dispatchmgr_t **mgrp) {
	isc_mem_t *mctx;
	dns_dispatchmgr_t *mgr;

	mgr = *mgrp;
	*mgrp = NULL;

	mctx = mgr->mctx;

	mgr->magic = 0;
	mgr->mctx = NULL;
	DESTROYLOCK(&mgr->lock);
	mgr->state = 0;

	isc_mempool_destroy(&mgr->epool);
	isc_mempool_destroy(&mgr->rpool);
	isc_mempool_destroy(&mgr->dpool);
	isc_mempool_destroy(&mgr->bpool);

	DESTROYLOCK(&mgr->pool_lock);

	if (mgr->entropy != NULL)
		isc_entropy_detach(&mgr->entropy);
	if (mgr->qid != NULL)
		qid_destroy(mctx, &mgr->qid);

	DESTROYLOCK(&mgr->buffer_lock);

	if (mgr->blackhole != NULL)
		dns_acl_detach(&mgr->blackhole);

	if (mgr->portlist != NULL)
		dns_portlist_detach(&mgr->portlist);

	isc_mem_put(mctx, mgr, sizeof(dns_dispatchmgr_t));
	isc_mem_detach(&mctx);
}

static isc_result_t
create_socket(isc_socketmgr_t *mgr, isc_sockaddr_t *local,
	      isc_socket_t **sockp)
{
	isc_socket_t *sock;
	isc_result_t result;

	sock = NULL;
	result = isc_socket_create(mgr, isc_sockaddr_pf(local),
				   isc_sockettype_udp, &sock);
	if (result != ISC_R_SUCCESS)
		return (result);

#ifndef ISC_ALLOW_MAPPED
	isc_socket_ipv6only(sock, ISC_TRUE);
#endif
	result = isc_socket_bind(sock, local);
	if (result != ISC_R_SUCCESS) {
		isc_socket_detach(&sock);
		return (result);
	}

	*sockp = sock;
	return (ISC_R_SUCCESS);
}

/*
 * Publics.
 */

isc_result_t
dns_dispatchmgr_create(isc_mem_t *mctx, isc_entropy_t *entropy,
		       dns_dispatchmgr_t **mgrp)
{
	dns_dispatchmgr_t *mgr;
	isc_result_t result;

	REQUIRE(mctx != NULL);
	REQUIRE(mgrp != NULL && *mgrp == NULL);

	mgr = isc_mem_get(mctx, sizeof(dns_dispatchmgr_t));
	if (mgr == NULL)
		return (ISC_R_NOMEMORY);

	mgr->mctx = NULL;
	isc_mem_attach(mctx, &mgr->mctx);

	mgr->blackhole = NULL;
	mgr->portlist = NULL;

	result = isc_mutex_init(&mgr->lock);
	if (result != ISC_R_SUCCESS)
		goto deallocate;

	result = isc_mutex_init(&mgr->buffer_lock);
	if (result != ISC_R_SUCCESS)
		goto kill_lock;

	result = isc_mutex_init(&mgr->pool_lock);
	if (result != ISC_R_SUCCESS)
		goto kill_buffer_lock;

	mgr->epool = NULL;
	if (isc_mempool_create(mgr->mctx, sizeof(dns_dispatchevent_t),
			       &mgr->epool) != ISC_R_SUCCESS) {
		result = ISC_R_NOMEMORY;
		goto kill_pool_lock;
	}

	mgr->rpool = NULL;
	if (isc_mempool_create(mgr->mctx, sizeof(dns_dispentry_t),
			       &mgr->rpool) != ISC_R_SUCCESS) {
		result = ISC_R_NOMEMORY;
		goto kill_epool;
	}

	mgr->dpool = NULL;
	if (isc_mempool_create(mgr->mctx, sizeof(dns_dispatch_t),
			       &mgr->dpool) != ISC_R_SUCCESS) {
		result = ISC_R_NOMEMORY;
		goto kill_rpool;
	}

	isc_mempool_setname(mgr->epool, "dispmgr_epool");
	isc_mempool_setfreemax(mgr->epool, 1024);
	isc_mempool_associatelock(mgr->epool, &mgr->pool_lock);

	isc_mempool_setname(mgr->rpool, "dispmgr_rpool");
	isc_mempool_setfreemax(mgr->rpool, 1024);
	isc_mempool_associatelock(mgr->rpool, &mgr->pool_lock);

	isc_mempool_setname(mgr->dpool, "dispmgr_dpool");
	isc_mempool_setfreemax(mgr->dpool, 1024);
	isc_mempool_associatelock(mgr->dpool, &mgr->pool_lock);

	mgr->buffers = 0;
	mgr->buffersize = 0;
	mgr->maxbuffers = 0;
	mgr->bpool = NULL;
	mgr->entropy = NULL;
	mgr->qid = NULL;