rbtdb.c

非常好的dns解析软件

				cleanup_nondirty(version, &cleanup_list);
			}
			/*
			 * If the (soon to be former) current version
			 * isn't being used by anyone, we can clean
			 * it up.
			 */
			if (cur_ref == 0) {
				cleanup_version = cur_version;
				APPENDLIST(version->changed_list,
					   cleanup_version->changed_list,
					   link);
			}
			/*
			 * Become the current version.
			 */
			version->writer = ISC_FALSE;
			rbtdb->current_version = version;
			rbtdb->current_serial = version->serial;
			rbtdb->future_version = NULL;

			/*
			 * Keep the current version in the open list, and
			 * gain a reference for the DB itself (see the DB
			 * creation function below).  This must be the only
			 * case where we need to increment the counter from
			 * zero and need to use isc_refcount_increment0().
			 */
			isc_refcount_increment0(&version->references,
						&cur_ref);
			INSIST(cur_ref == 1);
			PREPEND(rbtdb->open_versions,
				rbtdb->current_version, link);
		} else {
			/*
			 * We're rolling back this transaction.
			 */
			cleanup_list = version->changed_list;
			ISC_LIST_INIT(version->changed_list);
			rollback = ISC_TRUE;
			cleanup_version = version;
			rbtdb->future_version = NULL;
		}
	} else {
		if (version != rbtdb->current_version) {
			/*
			 * There are no external or internal references
			 * to this version and it can be cleaned up.
			 */
			cleanup_version = version;

			/*
			 * Find the version with the least serial
			 * number greater than ours.
			 */
			least_greater = PREV(version, link);
			if (least_greater == NULL)
				least_greater = rbtdb->current_version;

			INSIST(version->serial < least_greater->serial);
			/*
			 * Is this the least open version?
			 */
			if (version->serial == rbtdb->least_serial) {
				/*
				 * Yes.  Install the new least open
				 * version.
				 */
				make_least_version(rbtdb,
						   least_greater,
						   &cleanup_list);
			} else {
				/*
				 * Add any unexecuted cleanups to
				 * those of the least greater version.
				 */
				APPENDLIST(least_greater->changed_list,
					   version->changed_list,
					   link);
			}
		} else if (version->serial == rbtdb->least_serial)
			INSIST(EMPTY(version->changed_list));
		UNLINK(rbtdb->open_versions, version, link);
	}
	least_serial = rbtdb->least_serial;
	RBTDB_UNLOCK(&rbtdb->lock, isc_rwlocktype_write);

	/*
	 * Update the zone's secure status.
	 */
	if (version->writer && commit && !IS_CACHE(rbtdb))
		rbtdb->secure = iszonesecure(db, rbtdb->origin_node);

	if (cleanup_version != NULL) {
		INSIST(EMPTY(cleanup_version->changed_list));
		isc_mem_put(rbtdb->common.mctx, cleanup_version,
			    sizeof(*cleanup_version));
	}

	if (!EMPTY(cleanup_list)) {
		for (changed = HEAD(cleanup_list);
		     changed != NULL;
		     changed = next_changed) {
			nodelock_t *lock;

			next_changed = NEXT(changed, link);
			rbtnode = changed->node;
			lock = &rbtdb->node_locks[rbtnode->locknum].lock;

			NODE_LOCK(lock, isc_rwlocktype_write);
			if (rollback)
				rollback_node(rbtnode, serial);
			decrement_reference(rbtdb, rbtnode, least_serial,
					    isc_rwlocktype_write,
					    isc_rwlocktype_none);
			NODE_UNLOCK(lock, isc_rwlocktype_write);

			isc_mem_put(rbtdb->common.mctx, changed,
				    sizeof(*changed));
		}
	}

  end:
	*versionp = NULL;
}

/*
 * Add the necessary magic for the wildcard name 'name'
 * to be found in 'rbtdb'.
 *
 * In order for wildcard matching to work correctly in
 * zone_find(), we must ensure that a node for the wildcarding
 * level exists in the database, and has its 'find_callback'
 * and 'wild' bits set.
 *
 * E.g. if the wildcard name is "*.sub.example." then we
 * must ensure that "sub.example." exists and is marked as
 * a wildcard level.
 */
static isc_result_t
add_wildcard_magic(dns_rbtdb_t *rbtdb, dns_name_t *name) {
	isc_result_t result;
	dns_name_t foundname;
	dns_offsets_t offsets;
	unsigned int n;
	dns_rbtnode_t *node = NULL;

	dns_name_init(&foundname, offsets);
	n = dns_name_countlabels(name);
	INSIST(n >= 2);
	n--;
	dns_name_getlabelsequence(name, 1, n, &foundname);
	result = dns_rbt_addnode(rbtdb->tree, &foundname, &node);
	if (result != ISC_R_SUCCESS && result != ISC_R_EXISTS)
		return (result);
	node->find_callback = 1;
	node->wild = 1;
	return (ISC_R_SUCCESS);
}

static isc_result_t
add_empty_wildcards(dns_rbtdb_t *rbtdb, dns_name_t *name) {
	isc_result_t result;
	dns_name_t foundname;
	dns_offsets_t offsets;
	unsigned int n, l, i;

	dns_name_init(&foundname, offsets);
	n = dns_name_countlabels(name);
	l = dns_name_countlabels(&rbtdb->common.origin);
	i = l + 1;
	while (i < n) {
		dns_rbtnode_t *node = NULL;	/* dummy */
		dns_name_getlabelsequence(name, n - i, i, &foundname);
		if (dns_name_iswildcard(&foundname)) {
			result = add_wildcard_magic(rbtdb, &foundname);
			if (result != ISC_R_SUCCESS)
				return (result);
			result = dns_rbt_addnode(rbtdb->tree, &foundname,
						 &node);
			if (result != ISC_R_SUCCESS && result != ISC_R_EXISTS)
				return (result);
		}
		i++;
	}
	return (ISC_R_SUCCESS);
}

static isc_result_t
findnode(dns_db_t *db, dns_name_t *name, isc_boolean_t create,
	 dns_dbnode_t **nodep)
{
	dns_rbtdb_t *rbtdb = (dns_rbtdb_t *)db;
	dns_rbtnode_t *node = NULL;
	dns_name_t nodename;
	isc_result_t result;
	isc_rwlocktype_t locktype = isc_rwlocktype_read;

	REQUIRE(VALID_RBTDB(rbtdb));

	dns_name_init(&nodename, NULL);
	RWLOCK(&rbtdb->tree_lock, locktype);
	result = dns_rbt_findnode(rbtdb->tree, name, NULL, &node, NULL,
				  DNS_RBTFIND_EMPTYDATA, NULL, NULL);
	if (result != ISC_R_SUCCESS) {
		RWUNLOCK(&rbtdb->tree_lock, locktype);
		if (!create) {
			if (result == DNS_R_PARTIALMATCH)
				result = ISC_R_NOTFOUND;
			return (result);
		}
		/*
		 * It would be nice to try to upgrade the lock instead of
		 * unlocking then relocking.
		 */
		locktype = isc_rwlocktype_write;
		RWLOCK(&rbtdb->tree_lock, locktype);
		node = NULL;
		result = dns_rbt_addnode(rbtdb->tree, name, &node);
		if (result == ISC_R_SUCCESS) {
			dns_rbt_namefromnode(node, &nodename);
#ifdef DNS_RBT_USEHASH
			node->locknum = node->hashval % rbtdb->node_lock_count;
#else
			node->locknum = dns_name_hash(&nodename, ISC_TRUE) %
				rbtdb->node_lock_count;
#endif
			add_empty_wildcards(rbtdb, name);

			if (dns_name_iswildcard(name)) {
				result = add_wildcard_magic(rbtdb, name);
				if (result != ISC_R_SUCCESS) {
					RWUNLOCK(&rbtdb->tree_lock, locktype);
					return (result);
				}
			}
		} else if (result != ISC_R_EXISTS) {
			RWUNLOCK(&rbtdb->tree_lock, locktype);
			return (result);
		}
	}
	NODE_STRONGLOCK(&rbtdb->node_locks[node->locknum].lock);
	new_reference(rbtdb, node);
	NODE_STRONGUNLOCK(&rbtdb->node_locks[node->locknum].lock);
	RWUNLOCK(&rbtdb->tree_lock, locktype);

	*nodep = (dns_dbnode_t *)node;

	return (ISC_R_SUCCESS);
}

static isc_result_t
zone_zonecut_callback(dns_rbtnode_t *node, dns_name_t *name, void *arg) {
	rbtdb_search_t *search = arg;
	rdatasetheader_t *header, *header_next;
	rdatasetheader_t *dname_header, *sigdname_header, *ns_header;
	rdatasetheader_t *found;
	isc_result_t result;
	dns_rbtnode_t *onode;

	/*
	 * We only want to remember the topmost zone cut, since it's the one
	 * that counts, so we'll just continue if we've already found a
	 * zonecut.
	 */
	if (search->zonecut != NULL)
		return (DNS_R_CONTINUE);

	found = NULL;
	result = DNS_R_CONTINUE;
	onode = search->rbtdb->origin_node;

	NODE_LOCK(&(search->rbtdb->node_locks[node->locknum].lock),
		  isc_rwlocktype_read);

	/*
	 * Look for an NS or DNAME rdataset active in our version.
	 */
	ns_header = NULL;
	dname_header = NULL;
	sigdname_header = NULL;
	for (header = node->data; header != NULL; header = header_next) {
		header_next = header->next;
		if (header->type == dns_rdatatype_ns ||
		    header->type == dns_rdatatype_dname ||
		    header->type == RBTDB_RDATATYPE_SIGDNAME) {
			do {
				if (header->serial <= search->serial &&
				    !IGNORE(header)) {
					/*
					 * Is this a "this rdataset doesn't
					 * exist" record?
					 */
					if (NONEXISTENT(header))
						header = NULL;
					break;
				} else
					header = header->down;
			} while (header != NULL);
			if (header != NULL) {
				if (header->type == dns_rdatatype_dname)
					dname_header = header;
				else if (header->type == 
					   RBTDB_RDATATYPE_SIGDNAME)
					sigdname_header = header;
				else if (node != onode ||
					 IS_STUB(search->rbtdb)) {
					/*
					 * We've found an NS rdataset that
					 * isn't at the origin node.  We check
					 * that they're not at the origin node,
					 * because otherwise we'd erroneously
					 * treat the zone top as if it were
					 * a delegation.
					 */
					ns_header = header;
				}
			}
		}
	}

	/*
	 * Did we find anything?
	 */
	if (dname_header != NULL) {
		/*
		 * Note that DNAME has precedence over NS if both exist.
		 */
		found = dname_header;
		search->zonecut_sigrdataset = sigdname_header;
	} else if (ns_header != NULL) {
		found = ns_header;
		search->zonecut_sigrdataset = NULL;
	}

	if (found != NULL) {
		/*
		 * We increment the reference count on node to ensure that
		 * search->zonecut_rdataset will still be valid later.
		 */
		new_reference(search->rbtdb, node);
		search->zonecut = node;
		search->zonecut_rdataset = found;
		search->need_cleanup = ISC_TRUE;
		/*
		 * Since we've found a zonecut, anything beneath it is
		 * glue and is not subject to wildcard matching, so we
		 * may clear search->wild.
		 */
		search->wild = ISC_FALSE;
		if ((search->options & DNS_DBFIND_GLUEOK) == 0) {
			/*
			 * If the caller does not want to find glue, then
			 * this is the best answer and the search should
			 * stop now.
			 */
			result = DNS_R_PARTIALMATCH;
		} else {
			dns_name_t *zcname;

			/*
			 * The search will continue beneath the zone cut.
			 * This may or may not be the best match.  In case it
			 * is, we need to remember the node name.
			 */
			zcname = dns_fixedname_name(&search->zonecut_name);
			RUNTIME_CHECK(dns_name_copy(name, zcname, NULL) ==
				      ISC_R_SUCCESS);
			search->copy_name = ISC_TRUE;
		}
	} else {
		/*
		 * There is no zonecut at this node which is active in this
		 * version.
		 *
		 * If this is a "wild" node and the caller hasn't disabled
		 * wildcard matching, remember that we've seen a wild node
		 * in case we need to go searching for wildcard matches
		 * later on.
		 */
		if (node->wild && (search->options & DNS_DBFIND_NOWILD) == 0)
			search->wild = ISC_TRUE;
	}

	NODE_UNLOCK(&(search->rbtdb->node_locks[node->locknum].lock),
		    isc_rwlocktype_read);

	return (result);
}

static inline void
bind_rdataset(dns_rbtdb_t *rbtdb, dns_rbtnode_t *node,
	      rdatasetheader_t *header, isc_stdtime_t now,
	      dns_rdataset_t *rdataset)
{
	unsigned char *raw;	/* RDATASLAB */

	/*
	 * Caller must be holding the node reader lock.
	 * XXXJT: technically, we need a writer lock, since we'll increment
	 * the header count below.  However, since the actual counter value
	 * doesn't matter, we prioritize performance here.  (We may want to
	 * use atomic increment when available).
	 */

	if (rdataset == NULL)
		return;

	new_reference(rbtdb, node);

	INSIST(rdataset->methods == NULL);	/* We must be disassociated. */

	rdataset->methods = &rdataset_methods;
	rdataset->rdclass = rbtdb->common.rdclass;
	rdataset->type = RBTDB_RDATATYPE_BASE(header->type);
	rdataset->covers = RBTDB_RDATATYPE_EXT(header->type);
	rdataset->ttl = header->ttl - now;
	rdataset->trust = header->trust;
	if (NXDOMAIN(header))
		rdataset->attributes |= DNS_RDATASETATTR_NXDOMAIN;
	rdataset->private1 = rbtdb;
	rdataset->private2 = node;
	raw = (unsigned char *)header + sizeof(*header);
	rdataset->private3 = raw;
	rdataset->count = header->count++;
	if (header->count == ISC_UINT32_MAX)
		header->count = 0;

	/*
	 * Reset iterator state.
	 */
	rdataset->privateuint4 = 0;
	rdataset->private5 = NULL;

	/*
	 * Add noqname proof.
	 */
	rdataset->private6 = header->noqname;
	if (rdataset->private6 != NULL)
		rdataset->attributes |=  DNS_RDATASETATTR_NOQNAME;
}

static inline isc_result_t
setup_delegation(rbtdb_search_t *search, dns_dbnode_t **nodep,
		 dns_name_t *foundname, dns_rdataset_t *rdataset,
		 dns_rdataset_t *sigrdataset)
{
	isc_result_t result;
	dns_name_t *zcname;
	rbtdb_rdatatype_t type;
	dns_rbtnode_t *node;

	/*
	 * The caller MUST NOT be holding any node locks.
	 */

	node = search->zonecut;
	type = search->zonecut_rdataset->type;

	/*
	 * If we have to set foundname, we do it before anything else.
	 * If we were to set foundname after we had set nodep or bound the
	 * rdataset, then we'd have to undo that work if dns_name_copy()
	 * failed.  By setting foundname first, there's nothing to undo if
	 * we have trouble.
	 */
	if (foundname != NULL && search->copy_name) {
		zcname = dns_fixedname_name(&search->zonecut_name);
		result = dns_name_copy(zcname, foundname, NULL);
		if (result != ISC_R_SUCCESS)
			return (result);
	}
	if (nodep != NULL) {
		/*
		 * Note that we don't have to increment the node's reference
		 * count here because we're going to use the reference we
		 * already have in the search block.
		 */