query.c

来自「非常好的dns解析软件」· C语言 代码 · 共 2,425 行 · 第 1/5 页

	     section++) {
		result = dns_message_findname(client->message, section,
					      name, type, 0, &mname, NULL);
		if (result == ISC_R_SUCCESS) {
			/*
			 * We've already got this RRset in the response.
			 */
			CTRACE("query_isduplicate: true: done");
			return (ISC_TRUE);
		} else if (result == DNS_R_NXRRSET) {
			/*
			 * The name exists, but the rdataset does not.
			 */
			if (section == DNS_SECTION_ADDITIONAL)
				break;
		} else
			RUNTIME_CHECK(result == DNS_R_NXDOMAIN);
		mname = NULL;
	}

	/*
	 * If the dns_name_t we're looking up is already in the message,
	 * we don't want to trigger the caller's name replacement logic.
	 */
	if (name == mname)
		mname = NULL;

	*mnamep = mname;

	CTRACE("query_isduplicate: false: done");
	return (ISC_FALSE);
}

static isc_result_t
query_addadditional(void *arg, dns_name_t *name, dns_rdatatype_t qtype) {
	ns_client_t *client = arg;
	isc_result_t result, eresult;
	dns_dbnode_t *node;
	dns_db_t *db;
	dns_name_t *fname, *mname;
	dns_rdataset_t *rdataset, *sigrdataset, *trdataset;
	isc_buffer_t *dbuf;
	isc_buffer_t b;
	dns_dbversion_t *version;
	isc_boolean_t added_something, need_addname;
	dns_zone_t *zone;
	dns_rdatatype_t type;

	REQUIRE(NS_CLIENT_VALID(client));
	REQUIRE(qtype != dns_rdatatype_any);

	if (!WANTDNSSEC(client) && dns_rdatatype_isdnssec(qtype))
		return (ISC_R_SUCCESS);

	CTRACE("query_addadditional");

	/*
	 * Initialization.
	 */
	eresult = ISC_R_SUCCESS;
	fname = NULL;
	rdataset = NULL;
	sigrdataset = NULL;
	trdataset = NULL;
	db = NULL;
	version = NULL;
	node = NULL;
	added_something = ISC_FALSE;
	need_addname = ISC_FALSE;
	zone = NULL;

	/*
	 * We treat type A additional section processing as if it
	 * were "any address type" additional section processing.
	 * To avoid multiple lookups, we do an 'any' database
	 * lookup and iterate over the node.
	 */
	if (qtype == dns_rdatatype_a)
		type = dns_rdatatype_any;
	else
		type = qtype;

	/*
	 * Get some resources.
	 */
	dbuf = query_getnamebuf(client);
	if (dbuf == NULL)
		goto cleanup;
	fname = query_newname(client, dbuf, &b);
	rdataset = query_newrdataset(client);
	if (fname == NULL || rdataset == NULL)
		goto cleanup;
	if (WANTDNSSEC(client)) {
		sigrdataset = query_newrdataset(client);
		if (sigrdataset == NULL)
			goto cleanup;
	}

	/*
	 * Look for a zone database that might contain authoritative
	 * additional data.
	 */
	result = query_getzonedb(client, name, qtype, DNS_GETDB_NOLOG,
				 &zone, &db, &version);
	if (result != ISC_R_SUCCESS)
		goto try_cache;

	CTRACE("query_addadditional: db_find");

	/*
	 * Since we are looking for authoritative data, we do not set
	 * the GLUEOK flag.  Glue will be looked for later, but not
	 * necessarily in the same database.
	 */
	node = NULL;
	result = dns_db_find(db, name, version, type, client->query.dboptions,
			     client->now, &node, fname, rdataset,
			     sigrdataset);
	if (result == ISC_R_SUCCESS)
		goto found;

	if (dns_rdataset_isassociated(rdataset))
		dns_rdataset_disassociate(rdataset);
	if (sigrdataset != NULL && dns_rdataset_isassociated(sigrdataset))
		dns_rdataset_disassociate(sigrdataset);
	if (node != NULL)
		dns_db_detachnode(db, &node);
	version = NULL;
	dns_db_detach(&db);

	/*
	 * No authoritative data was found.  The cache is our next best bet.
	 */

 try_cache:
	result = query_getcachedb(client, name, qtype, &db, DNS_GETDB_NOLOG);
	if (result != ISC_R_SUCCESS)
		/*
		 * Most likely the client isn't allowed to query the cache.
		 */
		goto try_glue;
	/*
	 * Attempt to validate glue.
	 */
	if (sigrdataset == NULL) {
		sigrdataset = query_newrdataset(client);
		if (sigrdataset == NULL)
			goto cleanup;
	}
	result = dns_db_find(db, name, version, type,
			     client->query.dboptions | DNS_DBFIND_GLUEOK,
			     client->now, &node, fname, rdataset,
			     sigrdataset);
	if (result == DNS_R_GLUE &&
	    validate(client, db, fname, rdataset, sigrdataset))
		result = ISC_R_SUCCESS;
	if (!WANTDNSSEC(client))
		query_putrdataset(client, &sigrdataset);
	if (result == ISC_R_SUCCESS)
		goto found;

	if (dns_rdataset_isassociated(rdataset))
		dns_rdataset_disassociate(rdataset);
	if (sigrdataset != NULL && dns_rdataset_isassociated(sigrdataset))
		dns_rdataset_disassociate(sigrdataset);
	if (node != NULL)
		dns_db_detachnode(db, &node);
	dns_db_detach(&db);

 try_glue:
	/*
	 * No cached data was found.  Glue is our last chance.
	 * RFC1035 sayeth:
	 *
	 *	NS records cause both the usual additional section
	 *	processing to locate a type A record, and, when used
	 *	in a referral, a special search of the zone in which
	 *	they reside for glue information.
	 *
	 * This is the "special search".  Note that we must search
	 * the zone where the NS record resides, not the zone it
	 * points to, and that we only do the search in the delegation
	 * case (identified by client->query.gluedb being set).
	 */

	if (client->query.gluedb == NULL)
		goto cleanup;

	/*
	 * Don't poision caches using the bailiwick protection model.
	 */
	if (!dns_name_issubdomain(name, dns_db_origin(client->query.gluedb)))
		goto cleanup;

	dns_db_attach(client->query.gluedb, &db);
	result = dns_db_find(db, name, version, type,
			     client->query.dboptions | DNS_DBFIND_GLUEOK,
			     client->now, &node, fname, rdataset,
			     sigrdataset);
	if (!(result == ISC_R_SUCCESS ||
	      result == DNS_R_ZONECUT ||
	      result == DNS_R_GLUE))
		goto cleanup;

 found:
	/*
	 * We have found a potential additional data rdataset, or
	 * at least a node to iterate over.
	 */
	query_keepname(client, fname, dbuf);

	/*
	 * If we have an rdataset, add it to the additional data
	 * section.
	 */
	mname = NULL;
	if (dns_rdataset_isassociated(rdataset) &&
	    !query_isduplicate(client, fname, type, &mname)) {
		if (mname != NULL) {
			query_releasename(client, &fname);
			fname = mname;
		} else
			need_addname = ISC_TRUE;
		ISC_LIST_APPEND(fname->list, rdataset, link);
		trdataset = rdataset;
		rdataset = NULL;
		added_something = ISC_TRUE;
		/*
		 * Note: we only add SIGs if we've added the type they cover,
		 * so we do not need to check if the SIG rdataset is already
		 * in the response.
		 */
		if (sigrdataset != NULL &&
		    dns_rdataset_isassociated(sigrdataset))
		{
			ISC_LIST_APPEND(fname->list, sigrdataset, link);
			sigrdataset = NULL;
		}
	}

	if (qtype == dns_rdatatype_a) {
		/*
		 * We now go looking for A and AAAA records, along with
		 * their signatures.
		 *
		 * XXXRTH  This code could be more efficient.
		 */
		if (rdataset != NULL) {
			if (dns_rdataset_isassociated(rdataset))
				dns_rdataset_disassociate(rdataset);
		} else {
			rdataset = query_newrdataset(client);
			if (rdataset == NULL)
				goto addname;
		}
		if (sigrdataset != NULL) {
			if (dns_rdataset_isassociated(sigrdataset))
				dns_rdataset_disassociate(sigrdataset);
		} else if (WANTDNSSEC(client)) {
			sigrdataset = query_newrdataset(client);
			if (sigrdataset == NULL)
				goto addname;
		}
		result = dns_db_findrdataset(db, node, version,
					     dns_rdatatype_a, 0,
					     client->now, rdataset,
					     sigrdataset);
		if (result == DNS_R_NCACHENXDOMAIN)
			goto addname;
		if (result == DNS_R_NCACHENXRRSET) {
			dns_rdataset_disassociate(rdataset);
			/*
			 * Negative cache entries don't have sigrdatasets.
			 */
			INSIST(sigrdataset == NULL ||
			       ! dns_rdataset_isassociated(sigrdataset));
		}
		if (result == ISC_R_SUCCESS) {
			mname = NULL;
			if (!query_isduplicate(client, fname,
					       dns_rdatatype_a, &mname)) {
				if (mname != NULL) {
					query_releasename(client, &fname);
					fname = mname;
				} else
					need_addname = ISC_TRUE;
				ISC_LIST_APPEND(fname->list, rdataset, link);
				added_something = ISC_TRUE;
				if (sigrdataset != NULL &&
				    dns_rdataset_isassociated(sigrdataset))
				{
					ISC_LIST_APPEND(fname->list,
							sigrdataset, link);
					sigrdataset =
						query_newrdataset(client);
				}
				rdataset = query_newrdataset(client);
				if (rdataset == NULL)
					goto addname;
				if (WANTDNSSEC(client) && sigrdataset == NULL)
					goto addname;
			} else {
				dns_rdataset_disassociate(rdataset);
				if (sigrdataset != NULL &&
				    dns_rdataset_isassociated(sigrdataset))
					dns_rdataset_disassociate(sigrdataset);
			}
		}
		result = dns_db_findrdataset(db, node, version,
					     dns_rdatatype_aaaa, 0,
					     client->now, rdataset,
					     sigrdataset);
		if (result == DNS_R_NCACHENXDOMAIN)
			goto addname;
		if (result == DNS_R_NCACHENXRRSET) {
			dns_rdataset_disassociate(rdataset);
			INSIST(sigrdataset == NULL ||
			       ! dns_rdataset_isassociated(sigrdataset));
		}
		if (result == ISC_R_SUCCESS) {
			mname = NULL;
			if (!query_isduplicate(client, fname,
					       dns_rdatatype_aaaa, &mname)) {
				if (mname != NULL) {
					query_releasename(client, &fname);
					fname = mname;
				} else
					need_addname = ISC_TRUE;
				ISC_LIST_APPEND(fname->list, rdataset, link);
				added_something = ISC_TRUE;
				if (sigrdataset != NULL &&
				    dns_rdataset_isassociated(sigrdataset))
				{
					ISC_LIST_APPEND(fname->list,
							sigrdataset, link);
					sigrdataset = NULL;
				}
				rdataset = NULL;
			}
		}
	}

 addname:
	CTRACE("query_addadditional: addname");
	/*
	 * If we haven't added anything, then we're done.
	 */
	if (!added_something)
		goto cleanup;

	/*
	 * We may have added our rdatasets to an existing name, if so, then
	 * need_addname will be ISC_FALSE.  Whether we used an existing name
	 * or a new one, we must set fname to NULL to prevent cleanup.
	 */
	if (need_addname)
		dns_message_addname(client->message, fname,
				    DNS_SECTION_ADDITIONAL);
	fname = NULL;

	/*
	 * In a few cases, we want to add additional data for additional
	 * data.  It's simpler to just deal with special cases here than
	 * to try to create a general purpose mechanism and allow the
	 * rdata implementations to do it themselves.
	 *
	 * This involves recursion, but the depth is limited.  The
	 * most complex case is adding a SRV rdataset, which involves
	 * recursing to add address records, which in turn can cause
	 * recursion to add KEYs.
	 */
	if (type == dns_rdatatype_srv && trdataset != NULL) {
		/*
		 * If we're adding SRV records to the additional data
		 * section, it's helpful if we add the SRV additional data
		 * as well.
		 */
		eresult = dns_rdataset_additionaldata(trdataset,
						      query_addadditional,
						      client);
	}

 cleanup:
	CTRACE("query_addadditional: cleanup");
	query_putrdataset(client, &rdataset);
	if (sigrdataset != NULL)
		query_putrdataset(client, &sigrdataset);
	if (fname != NULL)
		query_releasename(client, &fname);
	if (node != NULL)
		dns_db_detachnode(db, &node);
	if (db != NULL)
		dns_db_detach(&db);
	if (zone != NULL)
		dns_zone_detach(&zone);

	CTRACE("query_addadditional: done");
	return (eresult);
}

static inline void
query_discardcache(ns_client_t *client, dns_rdataset_t *rdataset_base,
		   dns_rdatasetadditional_t additionaltype,
		   dns_rdatatype_t type, dns_zone_t **zonep, dns_db_t **dbp,
		   dns_dbversion_t **versionp, dns_dbnode_t **nodep,
		   dns_name_t *fname)
{
	dns_rdataset_t *rdataset;

	while  ((rdataset = ISC_LIST_HEAD(fname->list)) != NULL) {
		ISC_LIST_UNLINK(fname->list, rdataset, link);
		query_putrdataset(client, &rdataset);
	}
	if (*versionp != NULL)
		dns_db_closeversion(*dbp, versionp, ISC_FALSE);
	if (*nodep != NULL)
		dns_db_detachnode(*dbp, nodep);
	if (*dbp != NULL)
		dns_db_detach(dbp);
	if (*zonep != NULL)
		dns_zone_detach(zonep);
	(void)dns_rdataset_putadditional(client->view->acache, rdataset_base,
					 additionaltype, type);
}

static inline isc_result_t
query_iscachevalid(dns_zone_t *zone, dns_db_t *db, dns_db_t *db0,
		   dns_dbversion_t *version)
{
	isc_result_t result = ISC_R_SUCCESS;
	dns_dbversion_t *version_current = NULL;
	dns_db_t *db_current = db0;

	if (db_current == NULL) {
		result = dns_zone_getdb(zone, &db_current);
		if (result != ISC_R_SUCCESS)
			return (result);
	}
	dns_db_currentversion(db_current, &version_current);
	if (db_current != db || version_current != version) {
		result = ISC_R_FAILURE;
		goto cleanup;
	}

 cleanup:
	dns_db_closeversion(db_current, &version_current, ISC_FALSE);
	if (db0 == NULL && db_current != NULL)
		dns_db_detach(&db_current);

	return (result);
}

static isc_result_t
query_addadditional2(void *arg, dns_name_t *name, dns_rdatatype_t qtype) {
	client_additionalctx_t *additionalctx = arg;
	dns_rdataset_t *rdataset_base;
	ns_client_t *client;
	isc_result_t result, eresult;
	dns_dbnode_t *node, *cnode;
	dns_db_t *db, *cdb;
	dns_name_t *fname, *mname0, cfname;
	dns_rdataset_t *rdataset, *sigrdataset;
	dns_rdataset_t *crdataset, *crdataset_next;
	isc_buffer_t *dbuf;
	isc_buffer_t b;
	dns_dbversion_t *version, *cversion;
	isc_boolean_t added_something, need_addname, needadditionalcache;
	isc_boolean_t need_sigrrset;
	dns_zone_t *zone;
	dns_rdatatype_t type;
	dns_rdatasetadditional_t additionaltype;

	if (qtype != dns_rdatatype_a) {
		/*
		 * This function is optimized for "address" types.  For other
		 * types, use a generic routine.
		 * XXX: ideally, this function should be generic enough.
		 */
		return (query_addadditional(additionalctx->client,
					    name, qtype));
	}

	/*
	 * Initialization.
	 */