client.c

bind 9.3结合mysql数据库

	}

 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;
	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;
	}